Abstract: BACKGROUND: Medicine is evolving on the whole, so laboratory medicine does. Great emphasis is currently presently placed on personalized medicine, particularly by many of the most influential healthcare-linked institutions, communities, organisations and companies. METHODS: Personalized medicine is an appealing terminology, meaning an individualised approach to patients for either diagnosis or treatment using the most advanced and proper scientific and technological tools, which has its basis on a consolidate literature regarding the main ways for drawing more useful information by laboratory tests. RESULTS: A novel approach tailored around personalized medicine would allow construction of a revolutionary healthcare framework, where a list of laboratory tests adopted for each individual should be descriptive enough of the personal metabolic characteristics, as to be useful in a lifelong perspective, with the needed adjustments due to peculiar genetic variations and/or diseases. CONCLUSIONS: By a "personalized" approach, supported by informatics and computer science, each individual would benefit of an "in progress" assessment and the variations from the steady state timely evidenced and acknowledged.
Abstract: OBJECTIVES: To investigate the relationship between fasting plasma glucose (FPG) and shortened activated partial thromboplastin time (APTT), an independent risk factor for thrombosis. DESIGN AND METHODS: We analyzed outpatients' results of coagulation tests and FPG. RESULTS: When compared with euglycemic subjects, those with impaired fasting glucose and diabetes displayed significantly shortened APTTs. CONCLUSIONS: This previously unreported association deserves scrutiny, because APTT is relatively inexpensive and it might identify diabetic patients at major risk of thrombosis.
Abstract: Severity assessment of patients with haemophilia A (HA) is traditionally based on FVIII activity (FVIII:C). Clinical phenotype of HA patients often differs between individuals with the same FVIII:C determined with clotting and chromogenic assays. The aim of this study was to assess the influence of the FVIII:C on thrombin generation (TG) assay parameters both in vitro and ex-vivo postinfusion plasma. For in-vitro approach, influence of FVIII:C was evaluated on TG parameters in several dilutions of a normal plasma pool with commercial FVIII-depleted-plasma (FVIIIDP) and in others experiments, adding increasing amounts of different commercial FVIII concentrates (Fanhdi, Haemate-P, Hemofil-M and Kogenate Bayer) to FVIIIDP. In a series of 50 postinfusion samples, from HA patients of different severity, we assayed TG and FVIII:C (chromogenic and clotting). In vitro experiments, the 50% of maximum TG peak (TGMP) was achieved using only 5% FVIII:C and the TGMP was obtained with 40% of normal VIII:C. Impaired response compared with normal plasma was found in FVIIIDP using addition of increasing amounts of different commercial FVIII concentrates. An overall good correlation between the two FVIII assays was observed (y = 0.9115x - 0.273, r = 0.975, P < 0.001); TGMP and the Lag-Phase-Time (LPT) provided some discrepant results when compared with the total range of FVIII:C measurements. In contrast, correlations for TGMP, LPT and endogenous thrombin potential were improved in samples restricted to FVIII:C <5%. We conclude that TG parameters tentatively could be a tool to tailor the global haemostatic capacity in haemophilic patients.
Abstract: INTRODUCTION: Since ancient times, competitive athletes have been familiar with the use of ergogenic aids and they will probably continue to use unfair and harmful substances in future, because their inclination to victory, along with the mirage of glory and money, will probably overcome health and legal risks. SOURCES OF DATA: We searched PubMed using the term doping over the period 1990 to the present day. We also included non-English journals. AREAS OF AGREEMENT: By literature searching, it emerges that the phenomenon of doping is complex and multifaceted. It involves a number of causes and factors that do not originate solely in the athletic field, making universality its main feature. It is in fact observed in all ages and levels of competition, and it concerns all sports, even the most unpredictable. AREAS OF CONTROVERSY: The high number of athletes testing positive for anti-doping controls attests that the current strategy might be analytically adequate to unmask most (but not all) doping practices, but it is probably ineffective to prevent athletes to dope and modify this upsetting trend. Growing points As doping parallels the use of medications, food supplements, alcohol and social drugs, a reinforced preventive policy is advisable. EMERGING AREAS FOR DEVELOPING RESEARCH: The current anti-doping policy should be replaced with a more efficient and practical strategy to identify and monitor abnormal and harmful deviations of the biochemical and haematological profiles.
Abstract: Laboratory diagnostics has undergone relevant changes in organization and complexity, providing new opportunities and risks. The skill and expertise required for laboratory professionals to fulfil the need of a continuously evolving scenario in diagnostics embrace now a variety of scientific, managerial and organizational issues. Translating into clinical practice new insights from basic science, particularly regarding omics, requires construction of a new and complex core curriculum for laboratory professionals. In addition, the integration of different areas of diagnostics within the same laboratory service is expected to improve efficiency and effectiveness.
Abstract: BACKGROUND: Pre-eclampsia is a heterogeneous syndrome ranging from mild hypertension and proteinuria to severe pre-eclampsia with complications, which can also be associated with an enhanced maternal inflammatory response. METHODS: Tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1), interleukin-6 (IL-6) and interferon-gamma (IFN-gamma) were evaluated by multiplexed sandwich enzyme-linked immunosorbent assay in 14 pre-eclamptic women, 57 normotensive pregnant women (20 in the first, 20 in the second and 17 in the third trimester) and 21 non-pregnant women. RESULTS: The concentration of serum TNF-alpha was lower than the sensitivity limit of the assay in all groups. The prevalence of measurable IL-1 and IL-6 values, but not that of IFN-gamma, increased significantly in the second and third trimesters of pregnancy. However, the percentage of subjects with higher or detectable values of pro-inflammatory cytokines was statistically different between pre-eclamptic women and those in the second and third trimester of physiological pregnancy. CONCLUSIONS: Results of this study do not support standard screening for pro-inflammatory cytokines (TNF-alpha, IL-1, IL-6 and IFN-gamma) in pre-eclampsia.
Abstract: RATIONALE, AIMS AND OBJECTIVES: Total quality in coagulation testing is a necessary requisite to achieve clinically reliable results. Evidence was provided that poor standardization in the extra-analytical phases of the testing process has the greatest influence on test results, though little information is available so far on prevalence and type of pre-analytical variability in coagulation testing. METHODS: The present study was designed to describe all pre-analytical problems on inpatients routine and stat samples recorded in our coagulation laboratory over a 2-year period and clustered according to their source (hospital departments). RESULTS: Overall, pre-analytic problems were identified in 5.5% of the specimens. Although the highest frequency was observed for paediatric departments, in no case was the comparison of the prevalence among the different hospital departments statistically significant. The more frequent problems could be referred to samples not received in the laboratory following a doctor's order (49.3%), haemolysis (19.5%), clotting (14.2%) and inappropriate volume (13.7%). Specimens not received prevailed in the intensive care unit, surgical and clinical departments, whereas clotted and haemolysed specimens were those most frequently recorded from paediatric and emergency departments, respectively. The present investigation demonstrates a high prevalence of pre-analytical problems affecting samples for coagulation testing. CONCLUSIONS: Full implementation of a total quality system, encompassing a systematic error tracking system, is a valuable tool to achieve meaningful information on the local pre-analytic processes most susceptible to errors, enabling considerations on specific responsibilities and providing the ideal basis for an efficient feedback within the hospital departments.
Abstract: The accurate standardization of the preanalytical phase is of pivotal importance for achieving reliable results of coagulation tests. Because information on the suitable storage conditions for coagulation testing is controversial, we aimed at investigating the sample stability with regard to the temperature and time before centrifugation. The activated partial thromboplastin time (aPTT), prothrombin time (PT), fibrinogen and D-dimer were assayed in specimens collected from 26 consecutive patients on antivitamin K therapy on the ACL TOP analyzer. Three primary 3.6-ml siliconized evacuated tubes containing 0.109 mol/l buffered trisodium citrate were sequentially collected from each patient. These three tubes were mixed, pooled and divided into seven identical aliquots. The first aliquot was immediately centrifuged according to the standard protocol [1500 g for 15 min at room temperature (RT)] and analyzed. The other aliquots were left for 3, 6 and 24 h, respectively, at RT or 4 degrees C, and then centrifuged and analyzed. Test results were compared with those obtained on the reference specimen. Statistically significant prolongations were observed for aPTT in all the samples. Such differences exceeded the analytical quality specifications for desirable bias in the samples stored for 24 h. A significant reduction, yet comprised within the desirable bias, was observed for PT and fibrinogen in uncentrifuged specimens stored at RT for 3 and 6 h. No significant biases could be recorded in D-dimer. In conclusion, a 6-h storage of uncentrifuged specimens at either RT or 4 degrees C may still be suitable to achieve results of routine coagulation testing comprised within the analytical quality specifications for desirable bias.
Abstract: The Beijing Olympics will begin in August 2008 and athletes will face an unpredictable challenge. Based on present data, Beijing is one of the most polluted megacities in the world; the air concentrations of carbon monoxide (CO), ozone, nitrogen oxides (NO and NO2), sulphur dioxide (SO2) and particulate matter approach or exceed the current limits established by U. S. Environmental Protection Agency (EPA). Although the athletes who will be competing in Beijing are physiologically very different to the participants in most published studies, and it is therefore difficult to predict individual responses, there is little doubt that the presence of these air pollutants might be detrimental to athletic performance due to the marked increase (up to 20-fold) in ventilatory rate and concomitant nasal and oral breathing. Moreover, mouth breathing often bypasses the noise during strenuous exercise, increasing the deleterious effects of pollutants on health and athletic performance. Although limited, each decrement in athletic performance would have a potentially deleterious impact on top-class athletes competing in the next Olympics in China. Several Olympic records are regularly broken during the Olympics. Will this be the case for Beijing?
Abstract: OBJECTIVE: The interpretation of biochemical testing in sportsmen requires caution. Although creatinine-based estimates of glomerular filtration rate (GFR) overcome some shortcomings of serum creatinine, there is scarce information on their use in endurance athletes. DESIGN: We evaluated GFR, estimated by the recommended Modification of Diet in Renal Disease (MDRD) equation in athletes. PARTICIPANTS: Seventy-six professional male cyclists, 71 amateur male cyclists, and 65 healthy sedentary matched controls were included in the study. RESULTS: The mean serum creatinine level was significantly higher in the sedentary subjects (81 microM) than in amateur (75 microM; P < 0.001) and professional cyclists (72 microM; P < 0.001), and it was also marginally higher in amateur than in professional cyclists (P = 0.049). The mean estimated GFR value increased throughout the three subgroups, being significantly lower in the sedentary population (98 mL.min.[1.73 m]) than in the subgroups of amateur (109 mL.min.[1.73 m]; P < 0.001) and professional cyclists (113 mL.min.[1.73 m]; P < 0.001), but it did not differ between amateur and professional cyclists (P = 0.116). The average intensity of daily physical exercise, but not the body mass index, was inversely associated with serum creatinine and positively associated with the estimated GFR. CONCLUSIONS: The MDRD equation should be used with caution in athletes, and it should consider intensity and type of physical exercise.
Abstract: This article addresses sources of error in the pre- and postanalytic phases of the testing cycle, using the collection of blood specimens as a paradigm for quality improvement in these phases of testing. The article focuses on appropriateness of the test request, patient and sample identification, criteria for acceptance and rejection of specimens, and the communication and interpretation of results.
Abstract: The graduation of medicine is a title necessary but not sufficient to practice the medical profession. In Italy, as in other countries, Laboratory Medicine teaching is an educational area integrated with relevant pre-clinical disciplines, supporting the main medical processes of patient diagnosis, prognosis, treatment monitoring, evolution following-up, risk screening and hidden/latent condition finding. In the modern concept of core curriculum of medical students, some cardinal aspects of Laboratory Medicine should be included and precisely: test ordering, preanalytical and analytical issues, test interpreting. Such learning objectives would ultimately contribute, by a procedural/methodological approach, to the process of either correctly diagnosing or proper decision making, at the patient's benefit. The present article provides an overview of Laboratory Medicine teaching in the core curriculum of medical students in Italy, and highlights specific tasks of laboratory competencies and skills required to optimize the learning abilities of the students.
Abstract: OBJECTIVE: To investigate the relationship between thyroid and kidney function. DESIGN AND METHODS: 13,383 results of serum creatinine and thyroid stimulating hormone (TSH) were retrieved from the database of our Laboratory. RESULTS: When compared with euthyroid subjects, those with TSH <0.2 mIU/L and >2.5 mIU/L had increased and decreased estimated glomerular filtration rate (e-GFR), respectively. TSH levels were an independent predictor of e-GFR. CONCLUSIONS: A mutual relationship was observed between kidney and thyroid status.
Abstract: BACKGROUND: The accurate identification of patients with acute myocardial infarction (AMI) remains one of the most difficult challenges facing emergency physicians. The introduction of early and reliable biomarkers of AMI should hence be acknowledged, since they would increase the efficiency of the diagnostic process. METHODS: A total of 2,276 consecutive patients referred to the emergency department for clinical symptoms suggestive for AMI underwent cardiac troponin T (cTnT) and D-dimer testing between January and December 2006. Patients sample were eligible for inclusion in this investigation if they had been collected prior to medication or intervention and 12-24 h after the time of patient's arrival to the emergency department, when the diagnostic efficiency of cTnT is the highest. cTnT was assayed on the Elecsys 2010 and test results were stratified according to the decisional threshold corresponding to the lowest TnT concentration associated with a 10% total imprecision in the assay (>0.03 microg/l). Plasma D-dimer was measured employing Vidas DD. RESULTS: The results of 741 patient's samples fulfilled the above criteria and were included in the study, 252 (34%) of whom had cTnT values>0.03 microg/l. The D-dimer value distribution (median and 95% C.I.) was significantly different in patients with cTnT values>0.03 microg/l than in those with cTnT values<0.03 microg/l (2,227 microg/l, 431-10,000 microg/l versus 1,039 microg/l, 143-6,338 microg/l; P<0.001). The area under the receiver operating characteristic (ROC) curve, was 0.734 (95% confidence interval: 0.715-0.753; P<0.001). At the 500 microg/l diagnostic threshold estimated by the ROC curve analysis, corresponding to the cut-off for the diagnosis of VTE, sensitivity and specificity of Vidas D-dimer were 95% and 27%, respectively. The positive and negative predictive values were estimated as 92% and 41%, respectively. In linear regression analysis, no significant association (r=0.090; P=0.077) was observed between D-dimer and cTnT in patients with cTnT levels exceeding the decisional threshold of the assay. CONCLUSIONS: Results of the present investigation on patients with AMI established by accepted diagnostic criteria (cTnT values above the decisional threshold of the assay associated with suggestive clinical symptoms), testify that D-dimer testing would not add clinically meaningful information to the sole determination of the cardiospecific troponins 12-24 h after patient's admission at the emergency department, when the cumulative data indicate that the diagnostic efficiency of cTnT is the highest.
Abstract: Inherited platelet disorders are a rare, but probably underdiagnosed, cause of symptomatic bleeding. They are characterized by abnormalities of platelet number (inherited thrombocytopenias), function (inherited disorders of platelet function) or both. This review briefly discusses the inherited platelet disorders with respect to molecular defects, diagnostic evaluation and treatment strategies.
Abstract: BACKGROUND: The laboratory diagnosis of von Willebrand Factor (VWF) deficiencies includes qualitative and quantitative measurements of VWF and clotting factor VIII (FVIII). Since the FVIII activity is frequently normal in patients with mild type 1 or 2 von Willebrand disease (VWD), there is controversy whether FVIII testing should accompany VWF Antigen (VWF:Ag) assay. METHODS: The aim of this study was to explore the correlation between VWF:Ag, VWF ristocetin cofactor activity (VWF:RCo) and FVIII in 213 consecutive patients undergoing screening for VWD. RESULTS: Forty-six patients were identified with VWF:Ag levels lower than the diagnostic threshold (54 IU/dl). A significant correlation was observed between VWF:Ag and VWF:RCo (r = 0.892; p < 0.001), VWF:Ag and FVIII (r = 0.834; p < 0.001), VWF:RCo and FVIII (r = 0.758; p < 0.001). Receiver operating characteristic curve analysis of the VWF:Ag assay revealed an area under the curve of 0.978 and 0.957 for detecting life-threatening values of FVIII (<30 IU/dl) and VWF:RCo (<40 IU/dl), respectively. The negative and positive predictive values at the VWF:Ag threshold value of 54 IU/dl were 100% and 33% for detecting life-threatening FVIII deficiencies, 94% and 80% for identifying abnormal values of VWF:RCo. CONCLUSIONS: Due to the excellent correlation between VWF:Ag and FVIII and to the diagnostic efficiency of VWF:Ag for identifying abnormal FVIII levels in patients with VWF deficiency, routine measurement of FVIII may not be necessary in the initial screening of patients with suspected VWD. However, the limited negative predictive value of VWF:Ag for identifying type 2 VWD does not allow to eliminate VWF:RCo or VWF:FVIIIB assays from the diagnostic workout.
Abstract: BACKGROUND: There is emerging evidence that serum cortisol might be independently associated with prothrombotic activity, suggesting that increased cortisol levels might finally contribute to the pathogenesis of atherosclerotic disorders. Since hypercoagulability is principally sustained by either defective naturally occurring anticoagulant mechanisms or to heightened coagulation factors, most of which are cumulatively explored by the activated partial thromboplastin time (APTT), the present investigation was designed to asses the potential relationship between morning serum cortisol, APTT and fibrinogen in a general population of healthy outpatients. METHODS: We performed a retrospective analysis on the database of our Laboratory Information System to retrieve results of morning serum cortisol, APTT and fibrinogen, which were performed on consecutive outpatients referred by general practitioners for routine blood testing over the previous 2 years. RESULTS: Cumulative results for morning serum cortisol, APTT and fibrinogen were retrieved for 302 adults >35 years old (M/F = 61/90; age 49 +/- 13 years; range 35-79). A statistically significant increased concentration of fibrinogen was observed in subject with morning serum cortisol values above the upper limit of the reference range (P < 0.001), whereas the concentration of APTT was not significantly different between the two subgroups of subjects with normal and increased morning serum cortisol (P = 0.432). This difference remained statistically significant even after adjusting for age and sex. In multivariable linear regression analysis, the concentration of fibrinogen, but not the value of the APTT, was significantly associated with morning serum cortisol. CONCLUSIONS: The results of this retrospective investigation confirm that baseline cortisol levels might predict higher fibrinogen in the general population. This potential biological interrelationship deserves further scrutiny for the potential implications on prediction and prevention of the cardiovascular risk.
Abstract: Physical activity is essential for weight control, for limiting onset and complications of chronic disorders and for preventing impaired insulin sensitivity. Little is known about the glycaemic adaptations of physically active subjects, especially elite and professional athletes. Thus, we evaluated the glycaemic control in elite and professional cyclists by assessing fasting plasma glucose (FPG) and glycated haemoglobin (HbA1c). The study population consisted of 47 male professional road cyclists, 72 male elite road cyclists and 58 male sedentary blood donors. A significant difference was observed for FPG between sedentary controls (96 +/- 8 mg/dL) and either elite (91 +/- 8 mg/dL; p < 0.001) or professional cyclists (89 +/- 8 mg/dl; p < 0.001). Athletes showed a consistent trend towards higher HbA1c values, reaching statistical significance between sedentary individuals and professional cyclists (5.2 +/- 0.3% versus 5.4 +/- 0.2%; p = 0.017). In multiple linear regression analysis, the intensity of physical exercise is inversely correlated with FPG (r = - 0.320; p < 0.001) and directly correlated with HbA1c (r = 0.190; p = 0.006). These results demonstrate a significant association between intensity of the training regimen and both FPG and HbA1c, highlighting the need for establishing the appropriate critical difference for the measurement of FPG and HbA1c according to the training and exercise workload.
Abstract: Recombinant activated factor VII (rFVIIa) was originally developed for the treatment of spontaneous and surgical bleeding of hemophiliacs with inhibitors. Along with the elucidation of its molecular mechanism of action, rFVIIa has been successfully used over the last few years in a wide range of non-hemophilic bleeding conditions. The aim of this review is to summarize the current clinical experience on the use of rFVIIa in the management of bleeding associated with congenital or acquired platelet disorders.
Abstract: Abstract Background: Due to the increasing migration flows mostly concerning Western countries, the problem of reference ranges and cut-off values is a living matter. In particular, the influence of ethnic origin on traditional and novel biochemical markers of cardiac damage, including cardiac troponin T (cTnT), ischemia modified albumin (IMA) and N-terminal prohormone brain natriuretic peptide (NT-proBNP), has not been investigated, to the best of our knowledge. Methods: CTnT, NT-proBNP and IMA were assayed by a Modular System in 34 apparently healthy black Africans originating mainly from Central Africa and in 34 apparently healthy white, non-immigrant Italians, matched for age and sex. Results: All the subjects investigated displayed cTnT values <0.01 ng/mL. Black Africans displayed significantly increased concentrations of serum IMA (107 vs. 92 kU/L, p<0.0001), but not of NT-proBNP (4.9 vs. 3.8 pmol/L, p=0.4), as compared to the white, non-immigrant Italians. Conclusions: The results of our investigation indicate that the reference ranges and the thresholds values of IMA, but not those of cTnT and NT-proBNP, may be different according to the ethnic origin of the population. Therefore, although the current decisional thresholds of both cTnT and NT-proBNP may be appropriate for diagnosing cardiac damage and dysfunction in the black African population, that of IMA may require a revision toward higher values. Clin Chem Lab Med 2008;46.
Abstract: Doping in sports is commonplace. The prevention of harm to the athlete, the guarantee of fair play, and a level playing field for all competitors are the basis of the current anti-doping strategies. As healthcare systems are forced to allocate increasing resources to prevent and treat the prevailing pathologies worldwide, funding for anti-doping campaigns will necessarily be restricted. Ideally, additional resources should be devoted to increasing the number of athletes tested, the panels of tests used, and the frequency of out-of-competition controls. Since doping prevention cannot be considered a priority for most healthcare systems, such an approach is unaffordable and an alternative framework should be devised, focused primarily on harm reduction rather than fair play. The identification of abnormal deviations from reference values, regardless of pathological or artificial causes, would allow the athlete to be followed and tested using conventional laboratory tests, which are affordable to governments and healthcare systems and available to clinical laboratories. Although this strategy would not detect cheating, it would safeguard athletes' health.
Abstract: Ischemic stroke in childhood is a rare but serious disorder, which is associated with significant morbidity and mortality. The lack of causal homogeneity in the aetiology of this disorder presents problems for predicting and preventing it, making the ischemic stroke in childhood a real dilemma for the clinician. Although a variety of potential inherited and acquired causes have been now identified, including cardiac pathologies, infections, prothrombotic, metabolic and vascular disorders, the aetiology of ischemic stroke in the young remains still unknown in more than one third of the patients. Presently, an appropriate evaluation of some hypercoagulable conditions seems justified in adults with stroke. However, the etiologic contribution of several thrombophilic conditions to initial and recurrent stroke in affected children has not been definitely clarified, since more powerful and influential non-thrombophilic risk factors are usually present, making the thrombophilia screening in such circumstance a matter of debate. In particular, the diagnostic yield of the screening is reportedly lower in children, the role of several prothrombotic abnormalities is uncertain, especially in recurrent stroke, and there is no evidence-based guidance to stroke prevention and therapy in children carrying a hypercoagulable state. Additional studies are needed to quantify the risk for a cerebrovascular event in children with a prothrombotic disorder and to determine which combination of endogenous and exogenous risk factors leads to greater rates of initial and recurrent stroke.
Abstract: CONTEXT: The measurement of cardiac troponin I (TnI) and T (TnT) is essential to diagnose, guide therapy, and predict outcomes of the acute coronary syndrome. Increased levels of troponins, especially TnT, are frequently observed in patients on chronic hemodialysis (HD), reflecting ongoing and subclinical myocardial damage. OBJECTIVE: Because these markers are increasingly used for stratification of cardiac risk in these patients, their behavior during HD should be acknowledged to optimize their clinical usefulness. DESIGN: TnI and TnT were measured in 34 patients pre-HD and post-HD by either high- or low-flux membranes. The post-HD concentrations were corrected for hemoconcentration. RESULTS: Pre-HD levels above the 99th percentile reference limits of the general population of TnI (>0.06 ng/ mL) and TnT (>0.01 ng/mL) were observed in 9% (13% high-flux, 6% low-flux membranes) and 88% (94% high-flux; 83% low-flux membranes) of the patients, respectively. No significant difference was observed in mean pre-HD values between patients dialyzed by low- and high-flux membranes. The overall decrease post-HD of both troponins (-21% and -17% for TnI and TnT, respectively) only reached statistical significance in patients dialyzed by low-flux membranes (-27% and -37% for TnI and TnT, respectively). A significant correlation was observed between absolute variations of TnI and TnT pre-HD to post-HD. CONCLUSIONS: Results of our investigation attest that high-flux membranes clear both troponins more efficiently from circulation than low-flux membranes. Therefore, sampling time and ultrafiltration coefficient of the HD membrane should be regarded as potential sources of variability in the clinical interpretation of troponin measurement in HD patients.
Abstract: The diagnostic approach to acute coronary syndrome (ACS) is challenging in patients with impaired renal function since most serum biomarkers are commonly increased in this clinical setting. Cardiac troponin T (cTnT), creatine kinase isoenzyme MB (CK MB), myoglobin, and ischemia modified albumin (IMA), were assayed in 45 patients prehemodialysis (pre-HD) and posthemodialysis (post-HD), and results were adjusted for hemoconcentration. The pre-HD values of serum IMA and cTnT were above the respective diagnostic thresholds (IMA<85 K units/L; cTnT <0.03 ng/mL) in six (13%) and 27 (60%) patients undergoing chronic HD, respectively. A significant (105.0 vs. 79.0 K units/L, P<0.0001) and variable (+38%; 95% confidence interval [CI], 12-65%) increase of serum IMA was observed post-HD, whereas the other biomarkers significantly decreased (cTnT: 0.029 vs. 0.044 ng/mL, P=0.016; CK-MB: 2.33 vs. 2.50 microg/L, P<0.0001; myoglobin: 128.1 vs. 148.7 microg/L, P<0.0001). Biomarkers of myocardial injury, especially cTnT and IMA, might be used in HD patients, provided that an appropriate diagnostic interpretation is guarantee, according to individual baseine value, metabolism, and time of sampling. Moreover, IMA might be reliably applied to stratify the long-term risk of these patients, but not for diagnosing an ACS during or immediately post-HD.
Abstract: OBJECTIVE: To evaluate the association between gamma-glutamyl transferase (GGT) and homocysteine in plasma. METHODS: Combined results of GGT, total homocysteine, vitamin B12, folate and creatinine levels were analyzed in outpatients referred for laboratory testing over the past 5 years. RESULTS: Cumulative results for homocysteine, GGT, B12, creatinine, folate could be retrieved for 449 outpatients > 35 years old over the study period. The concentration of homocysteine significantly increased among tertiles of GGT activity. In multivariable linear regression analysis, GGT activity was independently associated with homocysteine concentration, independent of age, gender, folate, vitamin B12 and serum creatinine levels. DISCUSSION: Plasma GGT activity might be a useful means to predict homocysteine concentration in the general population.
Abstract: High-pressure liquid chromatography instruments specifically devised for separating haemoglobin (Hb) fractions have been increasingly employed by the hospital laboratories over the recent years since they allow easy and fast screening for several Hb variants. Although such instruments may be proposed as sensitive, specific and reliable alternatives to the classic electrophoretic techniques, a major drawback of this screening strategy is the almost identical retention time of several Hb variants. In particular, at least 18 Hb variants have been reported in the same retention window as HbA(2), including HbE, the second most common beta-chain variant in humans after sickle cell trait. Recently, we evaluated the performance characteristics of an improved buffer formulation originally conceived for Hb variants separation procedures on the fully automated high-pressure liquid chromatography instrument Tosoh G7. At variance with other fully automated high-pressure liquid chromatography analyzers, the elution pattern on the G7 in subjects heterozygous for HbE is characterized by the presence of four suggestive peaks (HbF, HbA, HbA(2) and HbE), confirming the effective separation of HbE from HbA(2). Because of its potential value in the diagnosis of the thalassaemia syndromes, the effective separation of HbA(2) from HbE can provide clinical laboratories with a valuable information for the diagnostic reasoning.
Abstract: BACKGROUND AND AIMS: Flow mediated dilation (FMD) of peripheral conduit arteries is a well-established tool to evaluate endothelial function. The aims of this study are to apply the FMD model to cerebral circulation by using acetazolamide (ACZ)-induced intracranial vasodilation as a stimulus to increase common carotid artery (CCA) diameter in response to a local increase of blood flow velocity (BFV). METHODS AND RESULTS: In 15 healthy subjects, CCA end-diastolic diameter and BFV, middle cerebral artery (MCA) BFV and mean arterial blood pressure (MBP) were measured at basal conditions, after an intravenous bolus of 1g ACZ, and after placebo (saline) sublingual administration at the 15th and 20th minute. In a separate session, the same parameters were evaluated after placebo (saline) infusion instead of ACZ and after 10mug/m(2) bs and 300mug of glyceryl trinitrate (GTN), administered sublingually, at the 15th and 20th minute, respectively. After ACZ bolus, there was a 35% maximal MCA mean BFV increment (14th minute), together with a 22% increase of mean CCA end-diastolic BFV and a CCA diameter increment of 3.9% at the 3rd minute (p=0.024). There were no MBP significant variations up to the 15th minute (p=0.35). After GTN administration, there was a significant increment in CCA diameter (p<0.00001). CONCLUSIONS: ACZ causes a detectable CCA dilation in healthy individuals concomitantly with an increase in BFV. Upon demonstration that this phenomenon is endothelium dependent, this experimental model might become a valuable tool to assess endothelial function in the carotid artery.
Abstract: CONTEXT: Lipoprotein(a) (Lp(a)) is receiving major emphasis as an independent risk factor for cardiovascular disease. Results of studies on Lp(a) in patients with impaired renal function are contradictory, and no information is available on the association between Lp(a) and estimated glomerular filtration rate and cystatin C. OBJECTIVE: To evaluate the potential relationships among the biochemical markers creatinine, estimated glomerular filtration rate, and cystatin C and their association with Lp(a) in patients with impaired renal function. DESIGN: We performed a retrospective analysis using the database of our laboratory to retrieve results of Lp(a), creatinine, and cystatin C tests performed on consecutive outpatients referred by general practitioners for routine blood testing during the last year. RESULTS: Cumulative results for all of the above-mentioned variables were retrieved for 150 adults older than 35 years. After stratifying Lp(a) values according to thresholds of creatinine, estimated glomerular filtration rate, and cystatin C, no significant differences in Lp(a) concentration were observed in subjects with abnormal values of these biochemical markers. The prevalence of Lp(a) values greater than or equal to 300 mg/L was not significantly different in subjects with biochemical markers suggestive of impaired renal function, as compared with those without such markers. In multivariable linear regression analysis, none of the parameters tested was significantly associated with Lp(a). CONCLUSIONS: We suggest that unless renal function is completely compromised, measurement of biochemical markers of renal function might be relatively unimportant to improve clinical usefulness of Lp(a) testing.
Abstract: Although clinical evidence supports a plausible association between thyroid disorders and venous thrombosis, reliable evidence is so far lacking on the potential biological mechanisms and neither temporary nor permanent thromboembolic risk factors were constantly identified. We performed a 2-years retrospective analysis to retrieve combined results of activated partial thromboplastin time (APTT), prothrombin time (PT), fibrinogen, and thyroid stimulating hormone (TSH), performed on outpatients over 15 years of age and referred by general practitioners for routine blood testing. Cumulative results were retrieved for 1,329 such outpatients. Patients with hyperthyroidism had shortened APTT (28.4 vs. 29.4 s; P = 0.043) and higher fibrinogen (4.1 vs. 3.8 g/l; P = 0.028) values when compared with euthyroid patients, whereas no significant differences were observed between euthyroid patients and those with hypothyroidism. Hyperthyroid patients had also an increased prevalence of shortened APTTs (<25.5 s) and higher values of fibrinogen (>4.0 g/l) than those with normal thyroid function. This study confirms that hyperthyroidism might be associated with hypercoagulability due to shortened APTT and increased fibrinogen values. Should these findings be confirmed, consideration should be given to prevent thrombotic complications in patients with hyperthyroidism.
Abstract: BACKGROUND: Clinical chemistry testing is influenced by a variety of preanalytical variables, including sample preparation. The presence of a diluted plasma layer at the top of primary tubes containing plasma citrate has recently been reported. However, no indication is available so far on the potential non-homogeneous distribution of clinical chemistry analytes during centrifugation of primary tubes containing lithium-heparin as an additive. METHODS: A total of 40 lithium-heparin plasma samples were collected from volunteers and immediately centrifuged. An aliquot was obtained from the upper 0.4 mL of plasma (upper aliquot), 1.0 mL of plasma was discarded, and a second aliquot (lower aliquot) was obtained from the remaining plasma. The concentrations of alanine aminotransferase, albumin, alkaline phosphatase, amylase, amylase pancreatic, aspartate aminotransferase, direct bilirubin, total bilirubin, blood urea nitrogen, calcium, chloride, cholesterol, C-reactive protein (CRP), creatinine, creatine kinase, gamma-glutamyltransferase (GGT), glucose, high-density lipoprotein-cholesterol, iron, lactate dehydrogenase (LDH), magnesium, phosphate, potassium, total protein, sodium, triglycerides and uric acid were assayed on a Roche/Hitachi Modular System P according to the manufacturer's specifications and using proprietary reagents. Sodium, chloride and potassium were measured on a Roche/Hitachi Modular System using indirect ion-selective electrode methods. RESULTS: We observed a statistically significant difference between the upper and lower aliquots for CRP (3.88+/-0.67 vs. 3.94+/-0.68 mg/L; p=0.025), GGT (32.1+/-8.0 vs. 31.8+/-8.0 U/L; p=0.013), LDH (395+/-19 vs. 386+/-20 U/L; p=0.010) and triglycerides (1.29+/-0.09 vs. 1.27+/-0.09 mmol/L; p=0.001); results for the other analytes were not significantly different. In no case did the mean percentage bias recorded between aliquots exceed the current analytical quality specifications for desirable bias. CONCLUSIONS: The results of our investigation show that plasma layer stratification might occur in primary lithium-heparin tubes for a limited number of routine clinical chemistry tests, introducing a statistically significant bias in the measurement of GGT, LDH, triglycerides and CRP in the upper vs. the bottom section. When delayed testing is necessary for these parameters, we suggest that plasma should be separated after centrifugation and appropriately mixed before delayed/repeated analysis or aliquoting.
Abstract: Traditional chocolate is derived from the cocoa bean, which is one of the most concentrated sources of flavanols, a subgroup of the natural antioxidant plant compounds called flavonoids. Accumulating evidence from the past 10 years demonstrates that moderate consumption of chocolate, especially dark chocolate, may exert protective effects against the development of cardiovascular disease. Several mechanisms have been proposed to explain this positive influence, including metabolic, antihypertensive, anti-inflammatory, and anti-thrombotic effects, as well as effects on insulin sensitivity and vascular endothelial function. Should these results be confirmed in randomised, controlled, cross-over, multi-dose trials, then the pleasure associated with chocolate consumption might also be justified from health and psychological perspectives. However, since dark chocolate has substantially higher levels of flavonoids than milk chocolate, and milk proteins may inhibit absorption of flavonoids, it might be preferable to consume dark chocolate than the white (milk) variety.
Abstract: Phenobarbital, a long-acting barbiturate, is generally considered to be a fairly safe and effective drug; however, hepatotoxicity is an infrequent but potentially fatal adverse effect and there is little information on the serum activity of liver enzymes in patients on stable, long-term monotherapy. The serum activity of alanine aminotransferase (ALT) and gamma-glutamyltransferase (GGT) are measured along with phenobarbital as part of the routine biochemical measurement in 128 consecutive adult out-patients on stable, long-term phenobarbital treatment. The control population consists of 2468 consecutive outpatients matched for age and gender. The patients on long-term phenobarbital therapy had significantly higher serum activities of ALT (27 IU/L versus 23 IU/L, P < 0.001) and GGT (79 IU/L versus 24 IU /L, P < 0.001). The prevalence of subjects with abnormal GGT values, but not ALT, was significantly higher than that in the control population. No significant differences were observed in either the mean activity or the prevalence of abnormal values of ALT or GGT between patients with suboptimal and therapeutic concentrations of the drug. These results suggest that chronic phenobarbital therapy may be associated with a clinically significant elevation of serum GGT activity. If confirmed, a specific GGT reference range should be adopted. Moreover, in those patients presenting with high serum GGT activity, it would not be necessary to reduce the dosage, discontinue the drug or change to a different anti-epileptic medication.
Abstract: BACKGROUND: A caveat to strenuous and medium term physical exercise is the potential cardiovascular damage it may cause. In particular, there is still controversy regarding the behaviour of biochemical markers of heart damage and dysfunction following medium term endurance training. METHODS: Troponin T (TnT) and the N-terminal proB-type natriuretic peptide (NT-proBNP) were assessed before a 21-km half-marathon, at the end, and 3, 6, 24 h thereafter on 17 trained, middle-aged males. Results were corrected for plasma volume changes. RESULTS: All athletes finished the half-marathon run successfully and without any symptoms. Most of them were able to fulfill their personal expectations. The % PVC increased significantly immediately after the run, returned to values not significantly different from the baseline at 3 and 6 h, and showed a significant decrease of 4.4% on the following day. None of the cases showed an increase in the concentration of TnT the > 0.03 ng/ml threshold. Although the level of NT-proBNP increased significantly at the end of the run and remained statistically higher than the pre-half marathon value for the following 24 h, no athlete displayed values exceeding the cut-off concentration of 125 pg/mL. At any time point the delta increments of NT-proBNP from the pre-run values did not significantly correlate with the corresponding % PVC. CONCLUSIONS: Taken together, our results in healthy, middle-aged, trained individuals are consistent with the hypothesis that medium term aerobic exercise significantly influences NT-proBNP values for up to 24 h though no biochemical signs of myocardial necrosis can be detected.
Abstract: BACKGROUND: Due to the increasing migration flows mostly concerning Western countries, the problem of reference ranges and cut-off values is a living matter. In particular, the influence of ethnic origin on traditional and novel biochemical markers of cardiac damage, including cardiac troponin T (cTnT), ischemia modified albumin (IMA) and N-terminal prohormone brain natriuretic peptide (NT-proBNP), has not been investigated, to the best of our knowledge. METHODS: CTnT, NT-proBNP and IMA were assayed by a Modular System in 34 apparently healthy black Africans originating mainly from Central Africa and in 34 apparently healthy white, non-immigrant Italians, matched for age and sex. RESULTS: All the subjects investigated displayed cTnT values < 0.01 ng/mL. Black Africans displayed significantly increased concentrations of serum IMA (107 vs. 92 kU/L, p < 0.0001), but not of NT-proBNP (4.9 vs. 3.8 pmol/L, p = 0.4), as compared to the white, nonimmigrant Italians. CONCLUSIONS: The results of our investigation indicate that the reference ranges and the thresholds values of IMA, but not those of cTnT and NT-proBNP, may be different according to the ethnic origin of the population. Therefore, although the current decisional thresholds of both cTnT and NT-proBNP may be appropriate for diagnosing cardiac damage and dysfunction in the black African population, that of IMA may require a revision toward higher values.
Abstract: We evaluated the analytical performance of the new commercial HemosIL D-Dimer HS, a latex-enhanced turbidimetric immunoassay, from Instrumentation Laboratory for D-dimer measurement on the ACL TOP automated analyzer. The recommended cut-off for this immunoassay is 243 ng/ml. The within-run and between-run coefficients of variations of D-Dimer HS for low, intermediate and high D-dimer concentrations were: 3.3-6.6%, 2.3-2.6%, 2.4-3.2%, respectively. The assay was proven linear in a range of D-dimer concentrations comprised between 319 and 2274 ng/ml. Results of 171 citrated plasma samples were compared with those of the reference commercial immunoassay VIDAS D-Dimer. Although the nonparametric regression according to the method of Passing and Bablok and the relative Spearman's correlation coefficient were excellent (HemosIL D-Dimer HS = 1.30 x VIDAS - 384; r = 0.964, P < 0.001), some discrepancies could be observed in Bland-Altman plots analysis. On the basis of the present evaluation, we conclude that the analytical performance and the main technical features of new HemosIL D-Dimer HS assay make it a suitable method for the rapid quantification of D-dimer in clinical laboratories. Further studies are however needed to confirm the safety of the assay and to determine the most optimal cutoff level in patients with venous thromboembolism.
Abstract: BACKGROUND: Controversial data are available on the relationship between magnesium metabolism and glucose homeostasis. METHODS: We performed a retrospective analysis to retrieve results of serum magnesium and fasting plasma glucose (FPG) tests (7,659 outpatients >35 years old). RESULTS: Subjects with FPG value > 7.0 mmol/L were more likely to had hypomagnesemia. The frequency of hypomagnesemia was also significantly higher among those with high FPG values > 7.0 mmol/L. In multivariable linear regression analysis, magnesium was significantly associated with FPG only in patients with FPG > 7.0 mmol/L. CONCLUSIONS: Magnesium metabolism could be implicated in the glucose homeostasis, especially in patients with FPG values suggestive for diabetes.
Abstract: Authors are usually invited to follow the instructions to authors in scientific journals, because this section is likely to contain unique requirements, such as the references style requested. Authors not only must accurately check the instructions, but are also expected to verify references against the original documents before submitting the article, consuming a considerable amount of time. This aspect may contribute to the large number of references errors in scientific manuscripts, some of which would be prevented by introducing a more homogeneous and uniformed style. A variety of international, peer-reviewed journals currently requires a rather different style, especially for the numbers of authors to be cited, the placing of the year of publication, the style of the journal title. A broad implementation of reasonable standards of practice and consensus guidelines for the format of manuscript references should be promoted for an advantageous process for both the journals and the authors.
Abstract: The accurate estimation of glomerular filtration rate (GFR) is pivotal in sports medicine. However, there is controversial information on the acute influence of physical exercise on kidney function in healthy athletes. The estimated GFR (EGFR) was assessed by the recommended Modification of Diet in Renal Disease (MDRD) equation before a 21-km half-marathon, at the end, and 3, 6, 24 hrs thereafter on 17 trained, middle-aged males. Results were corrected for plasma volume changes. The mean EGFR at the baseline was 76 mL/min/1.73 m (2); it decreased at the end of the run (62 mL/min/1.73 m (2)) and for the following 3 hrs (68 mL/min/1.73 m (2)) and 6 hrs (70 mL/min/1.73 m (2)), though statistical significance was only achieved immediately after the run (mean decrease 16 %, p < 0.01). The frequency of athletes with EGFR below the normal threshold was higher than the baseline immediately after the race and for the following 6 hrs. Twenty-four hours after the run, the EGFR had returned to values similar and nonsignificantly different from those recorded at the baseline. These results attest that medium to high strains of running in healthy, middle-aged, trained individuals do not cause renal damage, but a limited and temporary decline in renal function.
Abstract: The prevalence of atherosclerotic cardiovascular disorders is constantly increasing worldwide, and the aging of the population will make this trend rather unlikely to be reversed. It is a diffuse, systemic, chronic disorder that starts early in childhood and progresses asymptomatically throughout the adult life. Later in life, it is clinically manifested as coronary artery disease, stroke, transient ischemic attack and peripheral occlusive arterial disease. The notions on the pathogenesis have been almost revolutionized over the past decades and over 300 risk factors have been associated with genesis, progression and complication of this challenging disorder. Particularly, biochemical risk factors and markers play a crucial role in all steps of atherosclerosis process, and entail a great relevance in risk stratification and early prevention.
Abstract: Preanalytical and biological variability both have strong influences on test results of coagulation. Beyond age and gender, increasing emphasis is now being given to a variety of demographic and lifestyle variables, including ethnicity, smoking, diet, and exercise, which should be taken into account when interpreting laboratory data. However, there is strong emerging evidence that additional environmental influences, such as pollutants and environmental chemicals, might contribute in a major way to biological variability. A large body of epidemiological evidence now exists to support the view that air pollutants are responsible for shortened prothrombin time, and decreased factor VII, tissue plasminogen activator and platelet count; on the other hand, evidence also suggests that air pollutants may significantly increase fibrinogen, factor VIII, von Willebrand factor and platelet hyperactivity. Although it is impractical to develop reference ranges specific to the daily concentration of air pollutants, the potential influence of air pollution on results of coagulation testing should be recognised when interpreting laboratory findings.
Abstract: OBJECTIVE: It is widely acknowledged that identification and treatment of gestational diabetes mellitus (GDM) results in better maternal and neonatal outcomes. However, the utility of the glucose challenge test (GCT) remains controversial regarding the diagnostic approach and decision making. METHODS: We performed a retrospective analysis on the database of our Laboratory Information System to retrieve results of GCT and oral glucose tolerance test (OGTT), which were performed on consecutive female outpatients referred by the gynecologists over the last 3 years. RESULTS: Cumulative results for GCT and OGTT were retrieved for 724 female outpatients and screening test was abnormal in 114 of them. This group was classified in terms of normal glucose tolerance (NGT), one abnormal value for the 100-g-3h OGTT (OAV) and GDM. GDM was diagnosed only in 34 subjects (4.7%). No statistically significant differences were observed in the basal plasma glucose and 1-h GCT values among groups. Multivariable logistic regression analysis demonstrated that age, OGTT values >or=180 mg/dL at 1 hour and OGTT values >or=155 mg/dL at 2 hours, but not GCT values, were independent predictors for GDM (p=0.048, p=0.012 and p<0.001, respectively). CONCLUSIONS: Results of our retrospective analysis on an unselected population are consistent with the hypothesis that GCT is not predictive of GDM and its diagnostic significance remains questionable.
Abstract: Objective. Although there is information on biochemical markers of muscle and cardiac damage following strenuous exercise, little is known about the kinetics of these markers in athletes performing sub-maximal exercise. Material and methods. Fifteen healthy, trained, Caucasian males took part in a 21-km run. Blood samples were collected before the run, immediately after (post), and 3 h, 6 h and 24 h thereafter. Biochemical markers of muscle and cardiac damage were evaluated on the Modular System, employing proprietary reagents. In no case did the concentration of troponin T increase by >0.03 ng/mL. The values of aspartate aminotransferase (AST), creatine kinase (CK), CK MB, lactate dehydrogenase (LDH) and myoglobin increased significantly immediately after the run and remained elevated 24 h thereafter. Results. The number of subjects with values above the upper limit of the relative reference ranges did not vary throughout the study period for AST and LDH, while it increased significantly for CK, CK MB and myoglobin. The major variation over the pre-run value was recorded for myoglobin (3-fold increment), whereas AST and LDH increased 1.1 and 1.3-fold, respectively. Conclusions. The results suggest the hypothesis that sub-maximal exercise influences the concentration of several biomarkers of muscle damage for up to 24 h with no biochemical signs of myocardial damage.
Abstract: Although macrocytosis might occur with frequency in patients with thyroid disorders, there is controversial information on the metabolic relationship between thyroid stimulating hormone (TSH), folic acid and B12 in the general population. We performed a retrospective analysis to retrieve results of serum folic acid, B12, and TSH performed on consecutive outpatients referred by general practitioners for routine blood testing over the last 2 years. A positive, significant trend towards increased values of folic acid, but not of B12, could be observed across the spectrum of TSH values suggestive for hypo- and hyperthyroidism. However, the prevalence of subjects with folic acid or B12 deficiency did not differ significantly among the subgroups of subjects. In multivariable linear regression analysis folic acid, but not B12, was associated with TSH levels. These results do not support the routine screening for either B12 or folic acid deficiency in subjects with subclinical disturbances of thyroid function, though we can not rule out that it might still be useful in patients with overt thyroid dysfunction.
Abstract: Although regular aerobic physical activity increases exercise capacity and plays a role in both primary and secondary prevention of a variety of chronic disorders, competitive physical exercise is associated with a significant increase of risk of sudden death in athletes, especially adolescents and young adults. Several pathogenetic mechanisms have been speculated, including silent cardiovascular conditions, mostly cardiomyopathy, premature coronary artery disease and congenital coronary anomalies. Uneventful events, especially commotio cordis, and abuse of unfair and dangerous performance-enhancing drugs, are also claimed as potential causes. Although identification of athletes at major risk and prevention of adverse events seems the more pervasive strategy, guidelines for screening athletes differ widely on international basis and even among the different Sport federations. The aim of this review was to compile the current knowledge on the prevalence and the most common causes of sudden death in sportsmen, providing an overview of the guidelines for pre-participation screening.
Abstract: BACKGROUND: Although there is comprehensive information on traditional biomarkers of muscle and cardiac damage following exercise, less is known on the kinetics of innovative markers, including ischemia modified albumin (IMA), glycogen phosphorylase isoenzyme BB (GPBB), carbonic anhydrase III (CAIII) and heart-type fatty acid-binding protein (H-FABP) in athletes performing a sub-maximal exercise. METHODS: A total of 10 healthy trained Caucasian males performed a 21-km run. Blood samples were collected before the run, immediately after (post), 3, 6 and 24 h thereafter. Cardiac troponin I (cTnI), myoglobin, creatine kinase isoenzyme MB (CK-MB), GPBB, CAIII and H-FABP were assayed using a new diagnostic system based on protein biochip array technology. IMA was measured by a commercial colorimetric assay on a Roche Modular system P. RESULTS: Significant variations by one-way analysis of variance were observed for CK-MB (p=0.013), myoglobin (p<0.001), GPBB (p=0.029), H-FABP (p<0.001), CAIII (p=0.006), but not for cTnI (p=1.00) and IMA (p=0.881). In particular, values of all the biomarkers tested, but cTnI and IMA, increased significantly immediately after the run. GPBB and H-FABP values returned to baseline 6 and 3 h thereafter, those of CAIII, CK-MB and myoglobin remained significantly elevated from the pre-run value up to 24 h after the run. The major variation over pre-run values was recorded for myoglobin (nearly 4-fold increment), whereas CAIII, CK-MB, GPBB and H-FABP increased by 2.9-, 1.8-, 1.4- and 1.2-fold, respectively. CONCLUSIONS: We conclude that a sub-maximal aerobic exercise influences the concentration of several markers of muscle damage. Except for IMA, not one of the emerging biomarkers tested can be safely used to rule out myocardial damage as well as cardiospecific troponins in patients who had undergone recent physical activity.
Abstract: OBJECTIVE: A strong, independent, association has recently been shown between higher red blood cell distribution width (RDW) and the risk of all-cause death and cardiovascular events. However, the mechanism(s) underlying this association remains unclear. Since impaired kidney function is a well-known risk factor for cardiovascular disease, we assessed whether RDW is associated with decreased kidney function. MATERIAL AND METHODS: We cross-sectionally assessed results of RDW, haemoglobin, main corpuscular volume (MCV) and serum creatinine levels in a large cohort of unselected adult outpatients consecutively referred by general practitioners for routine medical check-up. Glomerular filtration rate (GFR) was estimated using the abbreviated Modification of Diet in Renal Disease (MDRD) equation. RESULTS: Cumulative results of RDW, creatinine and other variables were retrieved from the database of our Laboratory Information System for 8,585 adult outpatients over a 3-year period. When participants were grouped according to RDW quartiles, there was a strong, graded, decrease in estimated GFR levels (ranging from 87+/-18 to 81+/-32 mL/min/1.73 m(2); p<0.0001). Accordingly, the percentage of participants with estimated GFR<60 mL/min/1.73 m(2) increased steadily across RDW quartiles (from 5 % to 19 %; p<0.0001). In logistic regression analysis, lower estimated GFR strongly predicted higher RDW levels (p<0.0001) independently of age, gender, MCV and haemoglobin values. CONCLUSIONS: Our findings suggest that there is an inverse, graded, association between RDW and kidney function tests in a large cohort of unselected adult outpatients.
Abstract: Although eosinophilia (eosinophil count >0.60 x 10(9)/l), is a prothrombotic condition, little is known on the association between eosinophil count in blood and first-line coagulations tests, including fibrinogen, activated partial thromboplastin time (APTT), prothrombin time (PT) and platelet count. Cumulative results of APTT, PT, fibrinogen, platelet and eosinophil counts were retrieved from 6,944 outpatients >15 years old referred to our laboratory for routine blood testing over the previous 3 years. The median value and the percentage of patients with abnormal values of platelet count and fibrinogen but not APTT and PT, were significantly higher in patients with eosinophilia. This epidemiological association in a large subset of patients provides an additional potential mechanism to explain the link between eosinophilia and thrombosis and is consistent with the hypothesis that platelet count and fibrinogen might be worthwhile assessing in the presence of an abnormal eosinophil count.
Abstract: OBJECTIVE: Paraoxonase-1 (PON1) is an esterase with antioxidant properties. Low PON1 enzyme activity or specific allelic polymorphisms seem to be associated with the risk of developing coronary artery disease or acute ischemic stroke (AIS). Our objective was to determine the distribution of both PON1 enzyme activity and its genotype in a group of patients with AIS. MATERIALS AND METHODS: PON1 activity and the relative Q192R and L55M polymorphisms in the PON1 gene were assessed on 126 survivors of a first AIS and in 92 healthy subjects. RESULTS: The genotype distribution for PON1 Q192R and L55M polymorphisms was similar in AIS patients and healthy subjects, but patients carrying the QRLL or RRLL genotype combination had lower PON1 enzyme activity compared with healthy subjects with the same genotype. CONCLUSION: We postulate that lower than expected PON1 enzyme activity within specific genotypes might explain the reported association between R and L alleles and the risk of developing AIS.
Abstract: Fibrin formation and removal occurs continuously during the development of malignancy. Accordingly, hemostatic disorders in cancer patients are a rather frequent observation and range from asymptomatic laboratory changes to massive thromboembolism or haemorrhage. We document the case of an asymptomatic women, who was enrolled as a healthy control in a study and showed up with a substantially increased D- dimer value. After ruling out the most probable sources of D-dimer elevation, such as thrombosis, inflammation and trauma, she underwent laboratory and radiological investigations for malignancy, which were consistent with a colorectal metastatic adenocarcinoma. This case allow us to hypothesize that screening for occult malignancy in the presence of apparently inexplicable elevated D-dimer values may be taken into consideration.
Abstract: The clinical laboratory is no longer its own limited ecosystem, as it is increasingly integrated with patient care, assisting diagnosis, monitoring therapies and predicting clinical outcomes. Although efforts and resources are continuously focused to achieve a satisfactory degree of analytical quality, there is clear evidence that the preanalytical phase is much more vulnerable to uncertainties and accidents, which can substantially influence patient care. Most errors within the preanalytical phase result from system flaws and insufficient audit of the operators involved in specimen collection and handling responsibilities, leading to an unacceptable number of unsuitable specimens due to in vitro hemolysis, clotting, insufficient volume, wrong container, contamination and misidentification. A reliable approach to overcome this problem entails prediction of accidental events (exhaustive process analysis, reassessment and rearrangement of quality requirements, dissemination of operating guidelines and best-practice recommendations, reduction of complexity and error-prone activities, introduction of error-tracking systems and continuous monitoring of performances), an increase in and diversification of defenses (application of multiple and heterogeneous systems to identify non-conformities), and a decrease in vulnerability (implementation of reliable and objective detection systems and causal relation charts, education and training). This policy, which requires integration between requirements and design, full commitment and interdepartmental cooperation, should make laboratory activity more compliant to the inalienable paradigm of total quality in the testing process.
Abstract: Preparation of blood specimens is a major bottleneck in the laboratory throughput. Reliable strategies for reducing the time required for specimen processing without affecting quality should be acknowledged, especially for laboratories performing stat analyses. The present investigation was planned to establish a minimal suitable centrifuge time for primary samples collected for routine coagulation testing. Five sequential primary vacuum tubes containing 0.109 mol/l buffered trisodium citrate were collected from 10 volunteers and were immediately centrifuged on a conventional centrifuge at 1500 x g, at room temperature for 1, 2, 5, 10 and 15 min, respectively. Hematological and routine coagulation testing, including prothrombin time, activated partial thromboplastin time and fibrinogen, were performed. The centrifugation time was inversely associated with residual blood cell elements in plasma, especially platelets. Statistically significant variations from the reference 15-min centrifuge specimens were observed for fibrinogen in samples centrifuged for 5 min at most and for the activated partial thromboplastin time in samples centrifuged for 2 min at most. Meaningful biases related to the desirable bias were observed for fibrinogen in samples centrifuged for 2 min at most, and for the activated partial thromboplastin time in samples centrifuged for 1 min at most. According to our experimental conditions, a 5-10 min centrifuge time at 1500 x g may be suitable for primary tubes collected for routine coagulation testing.
Abstract: BACKGROUND: Population-based epidemiological studies have shown a convincing association between increased gamma-glutamyltransferase (GGT) activity and components of the metabolic syndrome, type 2 diabetes, hypertension, ischaemic stroke and myocardial infarction. However, little information is available on the interaction between GGT activity and traditional or emerging markers of cardiovascular risk. METHODS: We performed a retrospective analysis to retrieve results of serum GGT, fasting plasma glucose (FPG), creatinine, LDL-cholesterol, HDL-cholesterol, triglycerides and lipoprotein(a) tests performed on outpatients referred by the general practitioners to our laboratory for routine blood testing during the last 5 years. RESULTS: The concentrations of most lipid parameters varied with increasing GGT activities. There were graded, positive, associations of GGT concentrations with LDL-cholesterol, triglycerides, atherogenic index of plasma (AIP) and the total to HDL-cholesterol ratio, whereas a negative association was observed with HDL-cholesterol. Lipoprotein(a) concentrations increased in parallel with GGT activity, though such trend did not reach statistical significance. The frequencies of subjects with undesirable values according to the NCEP-ATP III and AHA/ACC thresholds increased across the spectrum of GGT thresholds for all lipids parameters but lipoprotein(a). These associations remained statistically significant even after adjustment for gender, age, FPG and creatinine concentrations. In multiple linear regression analyses GGT activity predicted plasma concentrations of LDL-cholesterol, triglycerides, HDL-cholesterol (negatively), AIP and the total to HDL-cholesterol ratio independently of age, gender, impaired fasting glucose/diabetes and creatinine levels. CONCLUSIONS: The results of this large retrospective study indicate that increased GGT activities are independently associated with a more atherogenic lipid profile in general population.
Abstract: Prenatal diagnosis is aimed to provide reliable clinical information to parents and physician on the risk of having babies affected by inherited anomalies or genetic disorders. Placenta is not a barrier between the pregnant woman and her genetically different fetus, but it is the centre of a complex bidirectional transfer. The discovery of circulating fetal DNA in maternal blood has disclosed new strategies to perform noninvasive testing for prenatal diagnosis, without any harm for the fetus. The possibility to measure rapidly and reproducibly fetal cell-free DNA with noninvasive techniques has warranted many clinical applications: gender detection, diagnosis of fetal aneuploidy such as 13, 18 and 21 trisomies, complications of pregnancy, X-linked diseases, cystic fibrosis, and several others.
Abstract: The appropriate development of hemostasis encompasses a delicate equilibrium between anti- and prothrombotic forces developing during three distinct phases (primary hemostasis, coagulation and fibrinolysis) that are closely linked to each other and precisely regulated to close vessel wounds, promote vascular healing and maintain vessel patency. Imbalance in each of these systems produces either hemorrhagic or thrombotic disorders. Inherited bleeding disorders, caused by quantitative or qualitative alterations of either platelets or plasma proteins involved in blood coagulation and fibrinolysis, may lead to serious and lifelong bleeding conditions, the severity of which is inversely associated with the degree of the underlying defect. Rapid and reliable identification of these pathologies is worthy of focus to allow the adoption of appropriate substitutive or supportive antihemorrhagic therapies. Evaluation of the hemorrhage-prone patient requires careful recording of the medical history, attention to pertinent physical findings and the discretionary use of laboratory resources. Owing to the low diagnostic efficiency of clinical history and examination, an appropriate and reliable laboratory approach, encompassing first- and second-line testing, is essential to screen, diagnose and monitor patients with bleeding diatheses. As both the analytical sensitivity and responsiveness of traditional coagulation assays to different abnormalities differ widely, each laboratory should establish individual guidelines based on field experience and on reagent and instrument characteristics. Emerging evidence indicates that the implementation of global coagulation tests, such as the thrombin generation assay and clot waveform analysis, would provide additional information for clinical decision-making for patients with inherited bleeding disorders.
Abstract: Although there is comprehensive information on several parameters related to acute changes of the oxygen transport system in athletes, little information is available on chronic adaptations of the respiratory system at rest, as reflected by the out-of-competition venous blood-gas status. Such changes may represent markers of a more efficient oxygen metabolism at rest, associated with a superior physical recovery. Venous blood-gas status was investigated in two subpopulations of competitive athletes (47 male professional road cyclists, 72 male elite road cyclists) who had observed an 18-24-h resting period from the last training session, and 58 male sedentary blood donors. Significant differences were observed for the p50 values (the oxygen tension at which the haemoglobin is 50% saturated) between sedentary controls (25+/-1 mmHg) and either elite (26+/-1 mmHg; p<0.01) or professional athletes (27+/-0.8; p<0.01), whereas other conventional parameters of the venous blood-gas status (pH, P(O2), P(CO2) and saturation) did not differ significantly between the three study populations. Results of the present investigation suggest that intensive training may be associated with a right-shift of the standard oxygen dissociation curve, as attested by the increased p50. This rightward shift is usually considered a helpful adaptation, enabling a relatively more efficiently mechanism of oxygen delivery to the peripheral tissues, enabling physiological advantages during exercise and improved recovery.
Abstract: OBJECTIVE: A common threonine481serine polymorphism (T481S) has been shown in vitro to strongly activate the chloride channel Kb (CLC-Kb) expressed in the kidney, and the 481S allele has been associated with human hypertension. The study aim was to evaluate the association of the T481S polymorphism with blood pressure (BP) levels and the BP progression rate in Swedes. DESIGN AND METHODS: The cardiovascular cohort of the Malmö Diet and Cancer (MDC) study is a population surveyed in 1991-1996 (n=6103, DNA available on n=6055), 53% of whom had also been examined 11 +/- 4.4 years earlier in the Malmö Preventive Project (MPP). Hypertension was defined as having BP above 140/90 mmHg or being on antihypertensive therapy (AHT). Carriers of one or two copies of the 481S allele were compared with T481T homozygotes (noncarriers). RESULTS: Among individuals without AHT in the MDC study (n=4988) there was no difference between carriers (n=1164, 23%) and noncarriers (n=3824, 77%) in systolic BP (139.3 +/- 8.3 vs 139.2 +/- 8.3 mmHg, P = 0.82) or diastolic BP (86.0 +/- 9.1 vs 86.0 +/- 9.2 mmHg, P = 0.95). In subjects free from AHT at the MPP and MDC studies (n=2627) there was no difference between carriers (n=607, 23%) and noncarriers (n=2020, 77%) in progression of systolic BP (2.1 +/- 2.6 vs 2.0 +/- 2.8 mmHg/year, P = 0.72) or diastolic BP (0.57 +/- 1.4 vs 0.58 +/- 1.6 mmHg/year, P = 0.85) from MPP to MDC. Multivariate analysis gave no support of interaction between the CLC-Kb T481S polymorphism, gender, age or body mass index regarding their effect on BP. CONCLUSION: Our data do not support a role of the CLC-Kb T481S polymorphism in BP regulation in Swedes.
Abstract: OBJECTIVE: There is controversial evidence on a matrix influence on the measurement of NT-proBNP. DESIGN AND METHODS: We compared results of Elecsys NT-proBNP measurement on serum, K2 EDTA plasma and lithium heparin plasma. RESULTS: Samples collected in K2 EDTA showed a marginally significant underestimation when compared to serum and heparin, whereas no significant difference was observed between serum and heparin plasma. CONCLUSIONS: Serum, heparin and K2 EDTA plasma may be suitable for NT-proBNP measurement.
Abstract: BACKGROUND: The appropriate clinical interpretation of Von Willebrand factor (VWF) measurements is crucial since inherited or acquired deficiencies are responsible for a potentially life threatening bleeding disorder, whereas increased plasma concentrations may be associated with an increased thrombotic risk. Besides age and blood group, the variability introduced by the presence of an acute phase response might contribute to decrease the clinical usefulness of this measurement. METHODS: To investigate the relationship between conventional inflammatory markers and VWF, 387 consecutive unselected patients undergoing surgical procedures at our University Hospital were systematically investigated for routine laboratory testing, including also VWF Antigen (VWF:Ag), C-reactive protein (CRP) and the erythrocyte sedimentation rate (ESR) as parts of a routine preoperative screening program. RESULTS: After stratifying the study population according to the upper limit of the reference range of the two inflammatory markers, a significantly increased median VWF:Ag plasma concentration was observed for subjects with increased value of both CRP (CRP>5 mg/L=VWF:Ag>120 UI/dL; CRP<5 mg/L=VWF:Ag 98 UI/dL, p=0.003) and ESR (ESR>30 mm/hg=VWF:Ag>120 UI/dL; ESR<30 mm/hg=VWF:Ag 96 UI/dL, p<0.001). A significantly different frequency distribution of VWF:Ag concentrations was also observed in subjects with values of inflammatory markers above the upper limits of the reference ranges when compared to those with normal values. In particular, the prevalence of subjects with VWF:Ag levels>120 UI/dL was six- and nearly three-times higher in subjects with abnormal values of CRP (55.8% versus 9.3%, p<0.001) and ESR (54.5% versus 18.7%, p<0.001), respectively. CONCLUSIONS: Results of this investigation demonstrate that the evaluation of conventional inflammatory markers would represent a valuable tool to enhance the clinical usefulness of VWF measurements, especially in patients with transitory and subclinical inflammation. Since VWF and factor VIII are likely to increase in parallel, we suggest that their measurements should be repeated at least after 6 months to one year in the presence of concomitantly increased values of inflammatory markers, such as ESR and/or CRP.
Abstract: OBJECTIVE: Systemic sclerosis (SSc) is a connective tissue disease characterized by tissue fibrosis that reflects an imbalance between collagen production and degradation. Matrix metalloproteinases (MMPs) are a family of endopeptidases involved in the remodelling of extracellular matrix (ECM). This activity is controlled by tissue inhibitors of MMP (TIMPs). Aim of this study was the evaluation of MMP-9/TIMP-1 and MMP-2/TIMP-2 systems in patients with SSc. DESIGN AND METHODS: SearchLight Human MMP Array 1 was used to measure MMPs and TIMPs in 32 SSc patients and 32 matched healthy controls. RESULTS: SSc patients showed higher values of both MMP-9 and TIMP-1 in comparison with controls. The patients with anticentromere antibodies (ACA) positivity showed higher values of MMPs and TIMPs in comparison with either controls or the patients with anti-Scl70-positive antibodies. CONCLUSION: Results of this investigation suggest that SSc patients with ACA positivity, after a primary fibrogenetic noxa, react with a more abundant release of MMP/TIMP, whereas patients with anti-Scl70 antibody show a normal response.
Abstract: The diagnostic approach to von Willebrand factor deficiencies is challenging and requires discretionary use of laboratory resources. Although extensive preoperative testing is not recommended, the activated partial thromboplastin time may be useful, especially in selected categories of patients. To establish the diagnostic sensitivity of this test to identify isolate von Willebrand factor deficiencies, 204 consecutive patients underwent a routine preoperative screening consisting of activated partial thromboplastin time, von Willebrand factor antigen, intrinsic pathway clotting factors activity, lupus anticoagulants and thrombin time. Thirty-seven patients were diagnosed with haemostasis disturbances other than von Willebrand factor deficiencies and were excluded from the evaluation. Isolated von Willebrand factor deficiency was diagnosed in 11 of the remaining 167 patients. A significant correlation was observed between von Willebrand factor antigen and activated partial thromboplastin time. Receiver operating characteristic curve analysis showed an area under the curve of 0.982 (95% confidence interval: 0.972-0.992; P < 0.001). At the 1.17 upper limit of the activated partial thromboplastin time, sensitivity and specificity were 100 and 85%, respectively, with negative and positive predictive values of 100 and 31%, respectively. These results demonstrate that activated partial thromboplastin time has an excellent diagnostic sensitivity and a satisfactory specificity for identifying isolated von Willebrand factor deficiencies.
Abstract: Physiologic pregnancy is associated with a broad series of metabolic adaptations which may also influence the metabolism of lipids and lipoproteins. Although the modification of serum lipids and lipoproteins has been exhaustively investigated during and after pregnancy, the relative changes recorded vary widely among the different studies. A comprehensive lipid and lipoprotein profile was evaluated in 57 women with uncomplicated pregnancies at different gestational ages (20 in the first, 20 in the second, and 17 in the third trimester of pregnancy) and compared to that of 21 non-pregnant women. Conventional lipid parameters, including total cholesterol, high-density lipoprotein cholesterol and triglycerides, were evaluated on the Modular System P. Low-density lipoprotein cholesterol was quantified by the formula of Friedewald, the atherogenic index of plasma was quantified by the formula log (triglycerides/high-density lipoprotein cholesterol), whereas lipoprotein(a) was assayed on the BN II nephelometric analyzer. We observed that all the lipid parameters tested were significantly modified by the gestational age; in particular, women in the second and third trimester displayed significantly increased total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, total to high-density lipoprotein cholesterol ratio, lipoprotein(a) and atherogenic index of plasma (third trimester only) when compared to either the control population or the subgroup of women in the first trimester of pregnancy. The value distributions and the relative percentage of women with undesirable or abnormal values according to the current NCEP or AHA/ACC goals were comparable between controls and women in the first trimester. However, when compared with either controls or women in the first trimester, advanced pregnancy was associated with an increased prevalence of undesirable or abnormal values for total cholesterol, low-density lipoprotein cholesterol and triglycerides in the second trimester, and total cholesterol, low-density lipoprotein cholesterol, triglycerides, total to high-density lipoprotein cholesterol ratio and lipoprotein(a) (only from non-pregnant women) in the third trimester. The results of this case-control study demonstrate that physiological pregnancy is associated with a substantial modification of the lipid and lipoprotein metabolism from the second trimester, providing reference ranges for traditional and emerging cardiovascular risk predictors throughout the gestational period.
Abstract: While the death rate from cancer has substantially decreased over the past decade, the search for effective and tolerable therapies is a great challenge as yet. The evidence that malignant cells cannot grow to a clinically detectable tumor mass and spread in the absence of an adequate vascular support, has opened a new area of research towards the selective inhibition or even destruction of tumor vessels. Angiostatin and angiostatin-related proteins are a family of specific angiogenesis inhibitors produced by tumors from a family of naturally occurring proteins, which also includes plasminogen and lipoprotein[a]. The anti-angiogenic activity of these proteins resides in cryptic and highly-repetitive molecular domains hidden within the protein moiety, called kringles. Lipoprotein[a] is an intriguing molecule consisting of a low-density lipoprotein core in addition to the covalently bound apolipoprotein[a]. Apolipoprotein[a] is characterized by an inactive protease domain, a single copy of the plasminogen kringle V and multiple repeats of domains homologous to the plasminogen kringle IV. Reliable studies on animal models indicate that the proteolytic break-down products of apolipoprotein[a] would posses anti-angiogenic and anti-tumoral properties both in vitro and in vivo, a premise to develop novel therapeutic modalities which may efficiently suppress tumor growth and metastasis. This review is focused on the biochemical structure, metabolism and the anti-angiogenic activity of this unique and elusive kringle-containing lipoprotein.
Abstract: BACKGROUND: The diagnostic approach to haemostatic defects in the newborn is challenging and requires appropriate interpretation of coagulation tests according to reference values dependent on the postnatal age. METHODS: This investigation was designed to study the postnatal development of the human coagulation system in newborn infants and to develop appropriate reference ranges for prothrombin time (PT), activated partial thromboplastin time (APTT) and fibrinogen (FBG) according at the day of birth and for the following postnatal period (days 1, 2, 3, 4, 5, 6, from 7 to 10 and from 11 to 44). RESULTS: The mean FBG value was already within the adult reference range in newborns at birth, the mean PT value fell within the adult reference range in infants aged 4 days or more, whereas the mean APTT value was still higher than the upper limit of the adult reference range in infants aged between 11 and 20 days. The prevalence of infants with pathological values according to the actual adult reference ranges was limited for FBG (from 24 to 7%), decreased from 92 to 8% in infants aged 0 and 11-20 days for PT, but remained elevated throughout the observational period for APTT (from 94 to 71%). CONCLUSIONS: The results of the present investigation demonstrate that the actual adult reference ranges for coagulation screening tests, especially PT and APTT, cannot be applied to newborns and young infants.
Abstract: In order to describe the haemostatic role of a variation in inhibitor reactivity with different factor VIII (FVIII) concentrates, we have compared inhibitor titres against a panel of FVIII concentrates and correlated titre with the capacity to inhibit thrombin generation. Three plasma-derived concentrates were tested in vitro in mixing experiments with inhibitor plasmas from 11 patients with severe haemophilia A: Fanhdi, which contains von Willebrand factor (VWF) with a final ratio of approximately 1:1 (VWF IU per IU FVIII:C); Haemate-P with a ratio of 2.5:1 and Hemofil-M containing only trace amounts of VWF. In addition, the recombinant FVIII concentrate Kogenate Bayer containing no VWF was included. Inhibitor titres and the capacity to generate thrombin were measured. A statistically significant difference in measured titres was found with the highest titres recorded against Hemofil-M. The inhibitor titres needed to inhibit 50% maximum thrombin generation were the lowest for Kogenate Bayer and the highest and similar for Fanhdi and Haemate-P with intermediate titres needed for inhibition of Hemofil-M. In this study, the thrombin generation assay provides additional indications for the role of VWF in the treatment of patients with inhibitors. The VWF-containing concentrates Fanhdi and Haemate-P, added to FVIII-deficient plasma with the presence of inhibitor, generate more thrombin than do the purified concentrates Hemofil-M and Kogenate Bayer.
Abstract: Motor racing is a dangerous sport and an inherently risky activity. The organisers of top-class motor sports championships, Formula One and MotoGP, have agreed on a set of regulations to reduce speed and improve safety over the last 10 years. These changes include limitations in weight, fuel and engine capacity. Nevertheless, there is evidence that most of the restrictions that have been introduced over the past 10 years have failed slow down vehicles, since the lap times have decreased almost linearly from 1995 to 2006 and drivers continue to die or to sustain serious injuries that keep them away from competition. Therefore, new and efficient measures should be adopted, such as lowering the cornering speed, having heavier and safer vehicles, having barriers surrounding the track to protect both spectators and competitors better, and having innovative clothing and protective devices to defend key anatomical structures while minimising the hindrance to the rider.
Abstract: BACKGROUND: Critical values' reporting is an essential requisite for clinical laboratories. Local policies were investigated within an indicative cohort of Italian laboratories to monitor the situation and establish a performance benchmark. METHODS: A five-point questionnaire was administered to 150 laboratory specialists attending the SIMEL (Italian Society of Laboratory Medicine) National Meeting in June 2006. RESULTS: A total of 107 questionnaires (71.3%) were returned with a 100% individual question response rate. Only 55% of the participants acknowledge critical values reporting as an essential practice, 80% admit that a comprehensive list of critical values is unavailable in the laboratory and 4% do not promptly communicate critical values. The list of critical values is variable among laboratories, ranging from none to 20 analytes included. The requesting physician or his/her office staff receives the great majority (97%) of notifications by telephone for outpatients. Critical values for inpatients are notified directly by telephone (81%) and in a minority of cases by either fax or computer (19%). In the inpatient setting, the information is notified to physicians (77%), nurses (15%) or other healthcare staff in the clinic (8%). It was found that 49% of the participants adopt a standard (digital or written) policy for routine recording of notifications; in 32% of the cases the registration is left to individual attitudes, whereas in 20% of the cases the notification is not recorded. No laboratory has yet adopted a read-back verification of the complete test result by the person receiving the information. CONCLUSIONS: The importance of critical value reporting is still poorly recognized in Italy and uniform or internationally accredited practices for communication and recording are not currently implemented.
Abstract: Background Evidence has been provided that lipoprotein(a) (Lp(a)) may be an important cardiovascular risk factor. Recognition of potential Lp(a) variability associated with common diseases, such as diabetes, chronic renal dysfunction, impaired liver function and acute/chronic inflammation, is important to optimize the clinical usefulness of this measurement. Methods We performed a retrospective analysis on our Laboratory Information System to retrieve results of fasting plasma glucose (FPG), creatinine, albumin, high sensitivity-C reactive protein (Hs-CRP) and Lp(a) tests, which were performed on all outpatients referred by general practitioners for routine blood testing during the last 5 years. Results Cumulative results for all of the above parameters were retrieved for 1,195 adults. After stratifying Lp(a) results according to the respective threshold values of albumin, estimated glomerular filtration rate (e-GFR), FPG and Hs-CRP, a significant difference was observed only among subjects with increased Hs-CRP levels (170 mg/l vs. 125 mg/l; P < 0.001). The frequency of Lp(a) values >/=300 mg/l was greater in those with increased Hs-CRP levels (36 vs. 26%; P = 0.037)-but not in those with abnormal values of albumin, e-GFR or FPG-compared with their counterparts with normal values of these parameters. In multiple regression analysis, age (r = 0.112; P < 0.001), Hs-CRP (r = 0.102; P = 0.001) and e-GFR (r = 0.106; P = 0.003) were independent predictors of Lp(a). Conclusions The evaluation of laboratory markers of glucose homeostasis and liver function seems unnecessary when measuring Lp(a) for cardiovascular risk assessment. Conversely, Hs-CRP and probably GFR might be of clinical value to identify individuals whose serum Lp(a) levels can be transiently or chronically increased.
Abstract: During the past few decades, great progress has been made toward a better understanding of the development of the hemostatic system. It is now clear that the physiology of hemostasis in pediatric patients differs widely from that in adults, supporting the hypothesis that children might have natural protective mechanisms that justify such variations. However, the correct interpretation of hemostasis test results in young patients, along with a deep understanding of the normal postnatal development in the human coagulation system, are essential prerequisites to the proper investigation of thrombotic and hemorrhagic problems in pediatric patients. Because the hemostatic system is not fully mature by 3 to 6 months of age, it is important to recognize that interpretation of laboratory data in pediatric patients must be accompanied by appropriate age-dependent reference ranges, which should also be specific for the testing system used, to prevent misclassification of children as having defects of factors and inhibitors of the coagulation system.
Abstract: PURPOSE: Gitelman's syndrome (GS) is an inherited autosomal recessive disorder due to loss of function mutations in the SLC12A3 gene encoding the Na-Cl co-transporter (NCCT), the target of thiazide diuretics. The defective function of the NCCT, which normally is expressed in the apical membrane of the distal convolute tubule in the kidney, leads to mild hypotension, hypokalemia, hyperreninemic hyperaldosteronism, mild metabolic alkalosis, hypomagnesemia and hypocalciuria. Up to now, more than 100 mutations of the SLC12A3 gene have been described in GS patients. METHODS: We have collected 30 patients from Sweden with a clinical diagnosis of GS and undertaken a mutation screening by SSCP and successive sequencing of the 26 exons and intronic boundaries. Both mutations were identified in most (n = 28, 93%) and at least one mutation was identified in all patients. RESULTS: We found 22 different mutations evenly distributed throughout the gene, 11 of which have not been described previously. The new variants include 8 missense mutations (Glu68Lys, His69Asn, Argl45His, Vall53Met, Gly230Asp, Gly342Ala, Val677Leu and Gly867Ser), 1 insertion (c.834_835insG on exon 6) and 2 splice-site mutations (c.2667 + lT>G substitution in splicing donor site after exon 22, c.1569-1G>A substitution in the splicing acceptor site before exon 13). CONCLUSION: In Swedish patients with the clinical features of GS, disease-causing mutations in the SLC12A3 gene were identified in most patients. The spectrum of GS mutations is wide making full mutation screening of the SLC12A3 gene necessary to confirm the diagnosis.
Abstract: Venous thromboembolism is a major health care problem worldwide and is sustained by a multifactorial pathogenesis where both congenital and acquired causes contribute. It is increasingly being highlighted that a reliable approach based on genomics and proteomics might be effective to construct a rational personalized medicine framework that can be applied in the preclinical, clinical, and therapeutic settings of venous thrombosis. The aim of this review is to provide a concise description of the current and future applications of genomics and proteomics in this challenging pathology.
Abstract: There is actual debate on a recent position of the World Anti-Doping Agency (WADA), which has cautiously refrained from banning hypoxic tents and intends to monitor their health risk. Regardless of teleological and deontological concepts, we highlight that the health risks inherent to the widespread use of these artificial performance-enhancing devices would make them as unsafe as other forms of blood doping.
Abstract: We evaluated the analytical performances of a new commercial chemiluminescent enzyme immunometric assay for d-dimer measurement on the Immulite 2000 automated analyser. The within- and between-run coefficients of variations for low, intermediate and high d-dimer concentrations ranged from 2.2% to 5.1% and from 2.9% to 6.0% respectively. The assay was proven linear in a range of d-dimer concentrations comprised between 324 and 7602 ng/ml. Comparison of samples collected in either 0.109 mol/l sodium citrate or lithium-heparin tubes by Bland-Altman plots and nonparametric regression analysis (y = 0.858x - 39, r = 0.997; P < 0.0001) revealed a minimum bias, almost completely attributable to the dilution effect of the anticoagulant. Results of 56 outpatients' citrated plasma samples analysed with the Immulite 2000 d-dimer assay were compared with those of the current reference commercial immunoassay on the Mini Vidas Immunoanalyser. Although the nonparametric regression according to the method of Passing and Bablok and the relative Spearman's correlation coefficient was satisfactory (Immulite = 1.001 x Vidas - 181; r = 0.937, P < 0.001), some random discrepancies could be observed in Bland-Altman plots analysis. The analytical accuracy, calculated as the area under the Receiver Operating Characteristic (ROC) curve (AUC), was 0.961 (P < 0.0001). On the basis of the results of the present evaluation, we conclude that the analytical performances and the main technical features of new Immulite 2000 d-dimer assay make it a suitable method for the rapid quantification of d-dimer in clinical laboratories.
Abstract: The measurement of beta-C-telopeptides of type I collagen (beta-CTX) reflects the rate of bone resorption in a variety of metabolic bone disorders and it is increasingly used to assist diagnosis and follow-up of these pathologies. Since preanalytical biases in the results of this marker can decrease its clinical usefulness, specific stability studies should be developed to prevent that inconsistent results of laboratory testing might affect patient health and waste economical resources. Three blood samples were simultaneously collected without venous stasis into evacuated tubes containing no additives, K2 EDTA or lithium heparin, from 23 out-patients referred to our phlebotomy service for routine laboratory testing. After centrifugation and separation of the specimens, a first aliquot was immediately analyzed, whereas a second and third aliquot was processed after a 24- and 48-hour storage at room temperature (21 degrees C). Beta-CTX was assayed on the automated electrochemiluminescence analyzer E170. A modest and clinically irrelevant underestimation was observed in lithium heparin plasma when compared with either K2 EDTA (-7.1%; 95% C.I. -2.0 to -12.3%; p < 0.001) or serum (-7.8%; 95% C.I. -3.2 to -12.4%; p < 0.001), but not between serum and K2 EDTA (+0.8%, 95% C.I. -5.3 to +6.9%; p = 0.260). Storage at room temperature in K2 EDTA plasma introduced a modest and clinically negligible decay in immunoreactivity (-4.4% and -5.7% at 24 and 48 hours, respectively), whereas storage at room temperature in both serum (-17.6% and -28.6% at 24 and 48 hours, respectively) and lithium heparin plasma (-29.1% and -44.0% at 24 and 48 hours, respectively) was associated with a substantial decay and a larger inter-individual variability in the measurable concentration of the analyte. In conclusion, the results of our investigation demonstrate that EDTA plasma is the most suitable sample matrix for the storage of beta-CTX at room temperature after centrifugation.
Abstract: BACKGROUND: The W allele of the G460W polymorphism in the adducin-1 gene has been occasionally associated with increased blood pressure (BP). The aim of this study was to test whether the G460W variant is associated with BP levels and BP progression rate and whether G460W associations with BP are affected by sex, body mass index (BMI), or age. METHODS: The G460W polymorphism was genotyped in the population-based Malmö Diet and Cancer-cardiovascular arm (MDC-CVA; n = 6103), of whom 53% had also been examined 11 +/- 4.4 years earlier in the Malmö Preventive Project (MPP). RESULTS: Among subjects without antihypertensive treatment (AHT) in the MDC-CVA (n = 5009), there was no difference between carriers (38%) and noncarriers (62%) of the W allele in systolic BP (139.2 +/- 18.2 v 139.2 +/- 18.5 mm Hg; P = .99) or diastolic BP (85.9 +/- 9.1 v 86.1 +/- 9.2 mm Hg; P = .49). In subjects free from AHT in the MPP and MDC (n = 2637) there was no difference between carriers (38%) and noncarriers (62%) in progression of systolic BP (2.0 +/- 2.5 v 2.0 +/- 2.7 mm Hg/year; P = .45) or diastolic BP (0.59 +/- 1.6 v 0.56 +/- 1.5 mm Hg/year; P = .66) from MPP to MDC. At MDC-CVA BP was influenced by interaction between the G460W and BMI (P = .02 for systolic BP and P = .002 for diastolic BP) and by interaction between G460W and sex (P = .03 for systolic BP and P = .02 for diastolic BP), a result further confirmed by stratified analysis showing that female carriers of the W allele belonging to the upper tertile of BMI had increased systolic BP (146.1 +/- 18.6 v 141.2 +/- 18.6 mm Hg; P < .001), diastolic BP (88.7 +/- 8.7 v 86.1 +/- 8.7 mm Hg; P < .001), and prevalence of hypertension (72.5% v 61.8 %; P = .001). CONCLUSIONS: Our data suggest that the G460W polymorphism influences BP when BMI and sex are taken into account.
Abstract: Plasma B-type natriuretic peptide (BNP) concentration was evaluated in end-stage renal disease patients to verify if measurements before or after the session could furnish different information. BNP levels in plasma from 52 hemodialysis (HD) patients were measured both before and after the first session of the week. Echocardiographic studies were also performed and patients were followed over a period of 28 months. BNP removal from plasma was influenced by equilibrated Kt/V and patient characteristics. Initial plasma BNP concentration was correlated both with cardiac systolic function (LVEF) and mortality rate, independent of blood sample timing (before or after HD). A relative risk of death of 2.67 was found for plasma BNP levels above 335 pg/mL or 232 pg/mL, before and after HD, respectively. Higher BNP levels were observed in patients with higher burden of comorbidity, as measured by the Charlson Comorbidity Index; however, statistical significance was obtained only for BNP measured before HD. In conclusion, measurement of plasma BNP could give a valuable risk stratification of HD patients while cutting costs, by confining echocardiographic studies only to cases with BNP levels above the established cutoff values.
Abstract: OBJECTIVES: There is debate on the influence of haemodialysis (HD) on lipoprotein(a). DESIGN AND METHODS: Lp(a), apo A, apo B and high-sensitivity C-reactive protein (hs-CRP) were measured in 46 patients pre- and post-HD. RESULTS: The median Lp(a) concentration significantly decreased post-HD (106 vs. 145 mg/L, p<0.001). No significant variations were observed for apo A, apo B and hs-CRP. Comparable results were observed with high- and low-flux membranes. CONCLUSION: HD is effective in lowering Lp(a).
Abstract: BACKGROUND: Regardless of the available recommendations to perform glycated haemoglobin testing at a 2- to 3-month frequency, there is increasing evidence of an inappropriate laboratory use of this test in clinical practice. METHODS: Data from our Laboratory Information System were analysed for glycated haemoglobin test orders over a 3-year period using Microsoft Excel to calculate the order intervals and the test frequency for each patient. To assess the appropriateness of repeat testing, only data for patients who had at least two separate glycated haemoglobin test results were included in the analysis. Inappropriate test orders were defined as any order for a given patient taking place within a 29- or 89-day period following the previous order. RESULTS: The results of our investigation demonstrate that inappropriate laboratory utilisation of this test is commonplace (26% of total repeat orders within 90 days), especially for inpatients (63.7% of inpatient repeat orders in less than 90 days). When stratifying glycated haemoglobin test results according to the >7% threshold, the frequency of inappropriate laboratory use (>90 days) was surprisingly greater among inpatients with a previous value of <7% than among those with a previous value of >7% (57.6% vs. 42.4%). The frequency of inappropriate glycated haemoglobin repeat test orders was lower among outpatients with a previous value of <7% than in outpatients with a previous value of >7% (64.8% vs. 35.2%). CONCLUSIONS: We conclude that more accurate application of the current recommendations would be advisable to decrease unnecessary testing and prevent avoidable health expenditure.
Abstract: The assessment and management of congestive heart failure relies increasingly on the measurement of B-type natriuretic peptide (BNP). However, the effective contribution of this biochemical test in the clinical decision making is influenced by reliability of the measure, which also depends on several preanalytical issues. Since there is controversy on the influence of the matrix and the storage conditions on BNP measurement, we compared results of BNP in serum, K2 ethylene diamine tetra-acetic acid (EDTA) plasma and lithium heparin plasma fresh samples and in matching samples stored at -20 and -80 degrees C for 1 week. BNP measured on the Bayer Advia Centaur was systematically underestimated in heparin plasma (-47%) and serum (-62%) when compared to K2 EDTA plasma. According to the established 100 ng/L cutoff value, 25% and 37% of the fresh samples collected in heparin plasma or serum were misclassified from the reference K2 EDTA fresh specimen, respectively. When compared to the fresh specimens, the mean and interindividual bias observed for samples stored at either -20 degrees C or -80 degrees C was, overall, modest for K2 EDTA plasma (-2%) and heparin plasma (+6% and -4%, respectively), though it appeared clinically meaningful in serum (+47% and +28%, respectively). Although we can not rule out that other BNP assays using different antibodies may be not affected from degradation during storage to the same extent, results of our investigation demonstrate that K2 EDTA plasma is the most suitable specimens for BNP testing on fresh and frozen samples stored at either -20 degrees C or -80 degrees C for up to 1 week.
Abstract: Oral anticoagulant therapy has been widely employed to prevent and treat a variety of thrombotic disorders, although a new generation of antithrombotic drugs, which offer inhibition of clot-bound as well as fluid-phase thrombin, has been developed and tested in several clinical trials. Although most anticoagulant responses to hydroxycoumarin compounds are well established, there are controversial evidences on their influence on activated factor VII (FVIIa). After analyzing the prothrombin time (PT) (International Normalized Ratio reference range, 0.92-1.08), factor VII clotting activity (FVII:C) (reference range, 75-130 U/dl) and activated factor VII clotting activity (FVIIa:C) (reference range, 30-110 U/l) in 46 consecutive patients on stable warfarin therapy for atrial fibrillation, a consistent trend towards decreased values of both FVII:C and FVIIa:C was observed as PT values increased. At moderate-intensity anticoagulation, with international normalized ratios between 2 and 3, the mean activities of FVII:C and FVIIa:C dropped to 28 U/dl (range, 9-61 U/dl) and 5.8 U/l (range, 1-18 U/l), respectively. Results of our investigations indicate that warfarin therapy decreases FVIIa:C, highlighting the potential benefits of oral anticoagulants in thrombotic disorders and other clinical conditions characterized by increased levels of FVIIa. Owing to the good correlation with FVIIa:C, we also hypothesize that the PT and/or FVII:C might be employed for monitoring recombinant FVIIa therapy.
Abstract: The number of circulating newly produced platelets depends on the thrombopoietic capacity of bone marrow as well as platelet removal from the bloodstream. Flow cytometric analysis with thiazole orange (TO), a fluorescent dye that crosses platelet membranes and binds intracellular RNA, has been used to measure circulating reticulated platelets (RPs) with high RNA content as an index of platelet turnover. We first assessed the specificity of TO flow cytometry and then applied this method in the diagnosis of thrombocytopenia caused by impaired platelet production or increased destruction. We also explored the utility of TO flow cytometry to predict thrombocytopoiesis after chemotherapy-induced bone marrow aplasia. Venous blood, anticoagulated with K(2)EDTA, was incubated with 0.6 microg/ml TO plus an anti-GPIIIa monoclonal antibody. The mean percentage of RPs in control subjects (n = 23) was 6.13 +/- 3.09%. RPs were 10.41 +/- 9.02% in patients (n = 10) with hematological malignancies during aplasia induced by chemotherapy and a significant increase in RPs (35.45 +/- 6.11%) was seen in the recovery phase. In 10 patients with idiopathic thrombocytopenic purpura, the percentage of TO positive platelets was 67.81 +/- 18.79 (P < 0.001 vs. controls). In patients with thrombocytopenia associated with hepatic cirrhosis (n = 21; 21.04 +/- 16.21%, P < 0.001 vs. controls) or systemic lupus erythematosus (n = 6, 29.08 +/- 15.57%; P < 0.001 vs. controls) increases in TO-stained platelets were also observed. Measurement of TO positive platelets may be a reliable tool for the laboratory identification of platelet disorders, with a higher sensitivity than measurement of platelet volume. Measurement of RPs may also prove useful to recognize the underlying pathogenetic mechanisms in thrombocytopenia.
Abstract: Remarkable advances in instrument technology, automation and computer science have greatly simplified many aspects of previously tedious tasks in laboratory diagnostics, creating a greater volume of routine work, and significantly improving the quality of results of laboratory testing. Following the development and successful implementation of high-quality analytical standards, analytical errors are no longer the main factor influencing the reliability and clinical utilization of laboratory diagnostics. Therefore, additional sources of variation in the entire laboratory testing process should become the focus for further and necessary quality improvements. Errors occurring within the extra-analytical phases are still the prevailing source of concern. Accordingly, lack of standardized procedures for sample collection, including patient preparation, specimen acquisition, handling and storage, account for up to 93% of the errors currently encountered within the entire diagnostic process. The profound awareness that complete elimination of laboratory testing errors is unrealistic, especially those relating to extra-analytical phases that are harder to control, highlights the importance of good laboratory practice and compliance with the new accreditation standards, which encompass the adoption of suitable strategies for error prevention, tracking and reduction, including process redesign, the use of extra-analytical specifications and improved communication among caregivers.
Abstract: Competition is a natural part of human nature. Techniques and substances employed to enhance athletic performance and to achieve unfair success in sport have a long history, and there has been little knowledge or acceptance of potential harmful effects. Among doping practices, blood doping has become an integral part of endurance sport disciplines over the past decade. The definition of blood doping includes methods or substances administered for non-medical reasons to healthy athletes for improving aerobic performance. It includes all means aimed at producing an increased or more efficient mechanism of oxygen transport and delivery to peripheral tissues and muscles. The aim of this review is to discuss the biochemistry, physiology, and complications of blood doping and to provide an update on current antidoping policies.
Abstract: Hematological manipulation to optimize aerobic performances is a serious problem in elite and professional sports and the approach to identify blood doping is as yet challenging. In most cases, the current strategy contemplates a first stage of analysis, based on the application of arbitrary threshold for hemoglobin or hematocrit, followed by second-generation blood tests, or the adoption of an individual hematological passport. To establish the influence of preanalytical variables on the athletes' hematological profile, we compared hemoglobin, hematocrit, and reticulocytes count in 27 male professional cyclists after a mean time of 2.30 +/- 0.12 tourniquet holding. Statistically significant differences were observed for hematocrit (+ 2.4 %; p < 0.001) and hemoglobin measurements (+ 1.4 %; p < 0.001), but not for the reticulocytes count (- 1.9 %; p = 0.170). In 4 out of 27 cases (15 %), the variability of the hematocrit measurement exceeded the 4.1 % desirable analytical quality specification for total error. Results of the present investigation further highlight the risk that unfulfillment of rigorous and standardized procedures for collection of blood specimens might increase the number of false positive testing and might lead to inappropriate sanctioning of a minority of clean athletes with hematocrit or hemoglobin values naturally elevated. Owing to the minor biological variability and the lesser susceptibility to variation of the preanalytical phase, the hemoglobin concentration might be a more suitable parameter than hematocrit for inclusion within laboratory testing to identify blood doping.
Abstract: BACKGROUND: Systemic sclerosis (SSc) is an autoimmune disorder of the connective tissue characterized by widespread vascular lesions and fibrosis. Little is known so far on the activation of the hemostatic and fibrinolytic systems in SSc, and most preliminary evidences are discordant. METHODS: To verify whether SSc patients might display a prothrombotic condition, plasma D-dimer was assessed in 28 consecutive SSc patients and in 33 control subjects, matched for age, sex and environmental habit. RESULTS AND DISCUSSION: When compared to healthy controls, geometric mean and 95% confidence interval (IC95%) of plasma D-dimer were significantly increased in SSc patients (362 ng/mL, IC 95%: 361-363 ng/mL vs 229 ng/mL, IC95%: 228-231 ng/mL, p = 0.005). After stratifying SSc patients according to disease subset, no significant differences were observed between those with limited cutaneous pattern and controls, whereas patients with diffuse cutaneous pattern displayed substantially increased values. No correlation was found between plasma D-dimer concentration and age, sex, autoantibody pattern, serum creatinine, erythrosedimentation rate, nailfold videocapillaroscopic pattern and pulmonary involvement. CONCLUSION: We demonstrated that SSc patients with diffuse subset are characterized by increased plasma D-dimer values, reflecting a potential activation of both the hemostatic and fibrinolytic cascades, which might finally predispose these patients to thrombotic complications.
Abstract: BACKGROUND: The diagnostic approach and the clinical management of patients presenting with suspected acute coronary syndrome or cardiac dysfunction are as yet challenging. Although ischemia modified albumin (IMA) and natriuretic peptides were recently proposed for detection of myocardial ischemia and cardiac dysfunction, little information is available on preanalytical and metabolic sources of variability of these markers. METHODS: To establish the influence of a regular endurance training and the relationship with conventional biochemical variables, NT-pro-brain natriuretic peptide (NT-proBNP) and IMA were assayed, along with cardiac troponin T (cTnT), lactate dehydrogenase (LDH), creatine kinase (CK), creatinine and albumin, in 35 sedentary healthy individuals and 50 male professional road cyclists, 12-24 h following the last demanding training session. RESULTS: Athletes displayed higher values of both LDH (299+/-61 vs. 257+/-36 U/l, P=0.002) and CK (184+/-123 vs. 115+/-74 U/l, P=0.011), and slightly lower concentrations of creatinine (82+/-12 vs. 87+/-9 micromol/l, P=0.044). No athlete or sedentary control displayed cTnT concentrations exceeding the lower sensitivity limit of the assay. As compared to the sedentary controls, main IMA concentration was increased in athletes (100+/-13 vs. 94+/-6 KU/l, P=0.035), whereas that of NT-proBNP appeared significantly decreased (2.8+/-1.6 vs. 4.3+/-34, P=0.005). The percentage of subjects displaying values exceeding the upper reference limit for the IMA assay was significantly different between athletes and sedentary controls (50% vs. 7%; P<0.001). Pearson correlation analysis revealed an inverse association between IMA and albumin in both athletes (r=-0.640; P<0.001) and sedentary controls (r=-0.583; P=0.001). CONCLUSIONS: Results of our investigation indicate that a demanding and regular aerobic training regimen, though able to trigger skeletal muscle sufferance, is not associated with any biochemical sign of severe and irreversible chronic cardiac involvement. Moreover, we suggest the adoption of specific IMA diagnostic thresholds following patients' stratification according to serum albumin concentration and physical activity.
Abstract: BACKGROUND: Systemic sclerosis (SSc) is an autoimmune disorder of the connective tissue characterized by widespread vascular lesions and fibrosis, associated with endothelial dysfunction, that might finally promote occlusive vascular complications. Little is known so far on the lipid profile of these patients. METHODS: To investigate the potential contribution of lipid abnormalities in genesis and progression of vascular occlusive complications, an extensive lipid profile, including total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, total cholesterol to HDL-C ratio, the atherogenic index of plasma, lipoprotein[a] (Lp[a]) and high-sensitive C Reactive Protein (Hs-CRP), was assessed in 31 consecutive female SSc patients and 33 matched healthy controls. RESULTS: When compared to healthy matched controls, SSc patients displayed statistically significant differences in median and 25-75th percentile distribution of Lp[a] (110 mg/l, 51-389 mg/l vs. 79 mg/l, 29-149 mg/l; P =0.005) and in the mean concentration of Hs-CRP (4.49 +/- 5.06 mg/l vs. 1.36 +/- 1.19 mg/l; P =0.001), but not in the other lipid parameters. When compared to the current NCEP or AHA/ACC goals, the values distributions and the relative percentage of patients with undesirable or abnormal vales were statistically different for Lp[a] (29% versus 3%) and Hs-CRP (42% vs. 12%) (both P <0.001). CONCLUSIONS: If further studies will strengthen these preliminary findings, owing to the growing evidence that Lp[a] might act in synergy with other defined prothrombotic conditions in the pathogenesis of a variety of vascular disorders, we hypothesize that Lp[a] measurement might be useful in SSc to identify and eventually treat subsets of patients more predisposed to develop thrombotic complications.
Abstract: CONTEXT: Preanalytical factors influencing the reliability of laboratory testing are commonplace. It is traditionally accepted that hemolytic samples are unsuitable for coagulation assays because of the release of hemoglobin, intracellular components, and thromboplastic substances from damaged blood cells. OBJECTIVE: To evaluate the influence of blood cell lysis on routine coagulation testing. DESIGN: Twelve aliquots prepared by serial dilutions of homologous lysated samples collected from 10 different subjects, and displaying a final percentage of lysis ranging from 0% to 9.1%, were tested for prothrombin time, activated partial thromboplastin time, fibrinogen, and dimerized plasmin fragment D. Lysis was achieved by subjecting citrated whole blood to a freeze-thaw cycle. OUTCOME MEASURES: Interference from blood cell lysis on routine coagulation testing. RESULTS: Statistically significant increases in prothrombin time and dimerized plasmin fragment D were observed in samples containing final lysate concentrations of 0.5% and 2.7% respectively, whereas significant decreases were observed in activated partial thromboplastin time and fibrinogen in samples containing a final lysate concentration of 0.9%. The current analytical quality specifications for desirable bias are +/-2.0% for prothrombin time, +/-2.3% for activated partial thromboplastin time, and +/-4.8% for fibrinogen. Percent variations from the baseline values exceeding the current analytical quality specifications for desirable bias were achieved for lysate concentrations of 0.9% (prothrombin time and activated partial thromboplastin time) and 1.8% (fibrinogen), corresponding to average free plasma hemoglobin concentrations of 1.7 and 3.4 g/L, respectively. CONCLUSION: Our results confirm that, although slightly hemolyzed specimens might still be analyzable, a moderate blood cell lysis, as low as 0.9%, influences the reliability of routine coagulation testing. Because the interference in coagulation assays has a wide interindividual bias, we do not recommend lysis correction and we suggest that the most appropriate corrective measure should be free hemoglobin quantification and sample recollection.
Abstract: BACKGROUND: Preanalytical factors are the main source of variation in clinical chemistry testing and among the major determinants of preanalytical variability, sample hemolysis can exert a strong influence on result reliability. Hemolytic samples are a rather common and unfavorable occurrence in laboratory practice, as they are often considered unsuitable for routine testing due to biological and analytical interference. However, definitive indications on the analytical and clinical management of hemolyzed specimens are currently lacking. Therefore, the present investigation evaluated the influence of in vitro blood cell lysis on routine clinical chemistry testing. METHODS: Nine aliquots, prepared by serial dilutions of homologous hemolyzed samples collected from 12 different subjects and containing a final concentration of serum hemoglobin ranging from 0 to 20.6 g/L, were tested for the most common clinical chemistry analytes. Lysis was achieved by subjecting whole blood to an overnight freeze-thaw cycle. RESULTS: Hemolysis interference appeared to be approximately linearly dependent on the final concentration of blood-cell lysate in the specimen. This generated a consistent trend towards overestimation of alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine, creatine kinase (CK), iron, lactate dehydrogenase (LDH), lipase, magnesium, phosphorus, potassium and urea, whereas mean values of albumin, alkaline phosphatase (ALP), chloride, gamma-glutamyltransferase (GGT), glucose and sodium were substantially decreased. Clinically meaningful variations of AST, chloride, LDH, potassium and sodium were observed in specimens displaying mild or almost undetectable hemolysis by visual inspection (serum hemoglobin < 0.6 g/L). The rather heterogeneous and unpredictable response to hemolysis observed for several parameters prevented the adoption of reliable statistic corrective measures for results on the basis of the degree of hemolysis. CONCLUSION: If hemolysis and blood cell lysis result from an in vitro cause, we suggest that the most convenient corrective solution might be quantification of free hemoglobin, alerting the clinicians and sample recollection.
Abstract: Laboratory testing is an integral part of the decision-making process, and results of laboratory testing often strongly influence medical diagnoses and therapies. There is a long history of quality requirements in laboratory medicine, which have mainly concerned the analytic phase of this process. Owing to the substantial advances in technology, laboratory automation and analytic quality, there is increasing evidence that further quality improvements should be targeted to extra-analytic phases of laboratory testing. Objective difficulties to monitor most of the preanalytic variables which lie outside the direct control or supervision of the laboratory personnel, such as phlebotomy, call for effective educational and preventive policies. Owing to high personnel turnover rates, lack of understanding about good laboratory practices, and inadequate training, there are several opportunities for making errors during phlebotomy, which mainly concern patient misidentification and collection of unsuitable specimens for testing due to unsuited venous accesses, venous stasis, inappropriate collection devices and containers. Improved standardization of phlebotomy techniques, along with operative guidelines dissemination, continuous education, certification, and training of health care professionals involved in blood drawing responsibilities would enhance the chance of obtaining specimens of consistent quality, with favorable revenues for the health care system and the patient's outcome.
Abstract: BACKGROUND: There is consolidated evidence that physical activity exerts beneficial effects on several chronic conditions and longevity, on the basis of its proposed biological effects, especially on lipid profiles. However, debate continues regarding the intensity of activity required for good health, as vigorous physical activity might overwhelm advantageous changes. In addition, little is known so far on the effect of a vigorous and regular aerobic training regimen on emerging markers of cardiovascular risk, such as lipoprotein(a), total/high-density lipoprotein cholesterol ratio and the atherogenic index of plasma. METHODS: To further investigate this topic, an extensive lipid profile, in accordance with the most recent guidelines issued by the American Heart Association (AHA)/American College of Cardiology (ACC) and the National Cholesterol Education Program (NCEP), was evaluated in 60 healthy male sedentary controls and in a wide population of professional endurance athletes, including 40 male professional cross-country skiers and 102 male professional road cyclists. RESULTS: Total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), triglycerides, TC low-density lipoprotein cholesterol (LDL-C) ratio and the atherogenic index of plasma were significantly lower in both categories of professional athletes, whereas the mean HDL-C concentration was significantly higher. The concentration of lipoprotein(a) did not differ significantly between the groups. When compared to current NCEP or AHA/ACC goals, the percentage of patients with undesirable values was statistically different for all parameters tested, apart from lipoprotein(a). According to multiple stepwise logistic regression analysis, lower TC/HDL-C ratio in professional skiers and lower TC/HDL-C ratio and TC in professional cyclists were significantly associated with increased aerobic physical activity. CONCLUSIONS: Results of this case-control study confirm that elevated aerobic energy expenditure might be associated with a highly favorable stabilization of most traditional and emerging cardiovascular risk predictors. Therefore, a substantial increase in aerobic physical activity within the population might be recommended to reverse adverse lipid abnormalities, especially in subjects with a higher cardiovascular risk.
Abstract: Laboratory diagnosis is traditionally a three-part process that develops within the preanalytic, analytic and post-analytic phases. There is consolidated evidence that lack of standardization and monitoring of preanalytic variables, including procedures for patient identification, sample collection, handling and processing has an adverse influence on the reliability of test results, consuming valuable healthcare resources and compromising the patient's outcome. The preanalytic phase enfolds the greatest potential for quality improvement, once reliable strategies are identified and applied. A comprehensive quality program should outstrip the traditional confines of clinical laboratories, encompassing reliable monitoring policies of the state of quality across the entire process. Such an approach requires the adoption of a reliable global quality monitoring system based on a core set of broad, evidence-based preanalytic performance measures. The present article synthesizes current evidence on this topic, defining a tentative approach for implementation of a preanalytic quality monitoring system in clinical laboratories.
Abstract: Self-monitoring of blood glucose (SMBG) is a cornerstone of diabetes care. However, the effectiveness of any glucose-monitoring programme depends on the ability to integrate SMBG into a program of self-care and therapeutic decision-making. Because the accuracy of SMBG is instrument dependent, we analysed 45 heparinized whole blood specimens using four marketed portable glucose meters to evaluate whether their precision and accuracy would be efficient and safe for clinical use. All measurements were standardized and performed by a single expert health-care professional at the same clinical chemistry laboratory. Results were compared with those obtained on the same plasma samples by the hexokinase method on a secondary reference analyser and further analysed according to the error tolerance criteria and the current American Diabetes Association (ADA), Clinical Laboratory Improvement Amendments (CLIA), and National Committee for Clinical Laboratory Standards (NCCLS) guidelines. The within-run imprecision ranged from 2.2% to 3.2%. Passing and Bablok regression analysis yielded slope values from 0.93 to 1.07 and correlation coefficients between 0.994 and 0.998. When compared with the secondary reference analyser, mean variations were between -4.9% and 14.1%, fulfilling in three out of four cases the 5.5% current desirable analytical quality specifications for total error. Nevertheless, when considering the two standard deviations level of this bias, several results exceeded this limit. Although three out of four devices tested achieved or came closer to the NCCLS C30-A2, CLIA and error tolerance targets, none of them met the current analytical ADA thresholds. Despite the acceptable analytical performances, we demonstrated that standardization and harmonization of results in SMBG have not been fully achieved.
Abstract: Considerable attention has been focused on definition and enhancement of the analytical quality in laboratory testing over the past decades. Advances in laboratory technology and computer informatics have allowed a major sense of confidence with the analytical phase and more efforts should now be focused on extra-analytical areas of improvement, that should further strengthen the link between cost effectiveness and clinical outcome. Deduction and implementation of common reference intervals, to be possibly shared by a regional network of clinical laboratories, appear so far a crucial step to increase efficiency and harmonization. With the experience gained from External Quality Control exercises and with the consensus of several contributory laboratories, this process is underway in Italy. Quality performances resulting from widespread implementation of common reference intervals and longitudinal comparison of patient's data, will allow clinical laboratories to accomplish with a major transferability, amplifying health benefits and meeting increasing health systems demand.
Abstract: BACKGROUND: Cardiovascular morbidity is frequent after non-cardiac surgery and the early recognition of cardiac involvement is an essential tool for clinical risk stratification and management. The aim of this study was to investigate the behavior of traditional and emerging cardiac markers, including NT-prohormone-brain natriuretic peptide (NT-proBNP) and ischemia-modified albumin (IMA), in the perioperative period in patients undergoing major uncomplicated orthopedic surgery. METHODS: A total of 37 patients undergoing major orthopedic surgery were longitudinally evaluated for NT-proBNP, IMA, cardiac troponin T (cTnT), creatine kinase isoenzyme MB and myoglobin 3 h before surgery and 4 and 72 h thereafter. RESULTS: NT-proBNP values were significantly increased at 72 h postoperative compared to both 3 h preoperative and 4 h postoperative (NT-proBNP: 20 vs. 4.5 pmol/L, p<0.001 and 20 vs. 5.9 pmol/L, p<0.001). IMA levels were significantly increased at 4 and 72 h postoperative vs. 3 h preoperative (132 vs. 113 kU/L, p=0.02 and 151 vs. 113 kU/L, p<0.001). In a stepwise regression model, the perioperative liquid amount and degree of modification in postoperative creatinine levels (delta-creatinine) were independently related to the NT-proBNP increase. CONCLUSIONS: The significant increase observed in NT-proBNP suggests that patients undergoing major uncomplicated orthopedic surgery may develop subclinical cardiac stress, presumably attributable to the considerable infusion of liquids. The clinical significance of this finding deserves further investigation, especially in patients at higher risk of heart failure.
Abstract: The diagnostic approach to acute coronary syndromes (ACS) remains one of the most difficult and controversial challenges facing emergency physicians. In recent years, cardiac troponins have emerged as the biochemical "gold standard" for diagnosis of patients with acute chest pain, enhancing our ability to recognize ACS. Early diagnosis and treatment of myocardial ischemia improve patient outcomes, but conventional markers are often nondiagnostic at the time of arrival at the emergency department. Promising new biomarkers, which appear earlier after the onset of ischemia, are being studied and integrated into clinical practice. Some are markers of myocyte necrosis, but others, including ischemia-modified albumin and natriuretic peptides, detect myocardial ischemia and myocardial dysfunction. The aim of the present article is to review the diagnostic approach to ACS, focusing on recent literature describing novel biochemical markers. If ongoing and future studies confirm their role in probability-based models risk assessment, a new era in the diagnostic approach to ACS may be dawning.
Abstract: Prolonged venous stasis, as generated by a long tourniquet placement, produces spurious variations in several measurable analytes. To verify to what extent venous stasis influences routine hematologic testing, we assessed routine hematologic parameters, including hemoglobin, hematocrit, red blood cell count (RBC), main cell hemoglobin (MHC), main cell volume (MCV), platelet count (PLT), main platelet volume (MPV), white blood cell count (WBC) and WBC differential on the Advia 120 automated hematology analyzer in 30 healthy volunteers, either without venous stasis (no stasis) or after application of a 60 mmHg standardized external pressure by a sphygmomanometer, for 1 (1-min stasis) and 3 min (3-min stasis). Although the overall correlation between measures was globally acceptable, the mean values for paired samples were significantly different in all parameters tested, except MCV, MHC, PLT, MPV, eosinophils, basophils and large unstained cells after 1-min stasis and all parameters except MCV, MHC, MPV and basophils after 3-min venous stasis. As expected RBC, hemoglobin and hematocrit displayed a significant trend towards increase, whereas WBC and the WBC subpopulations were decreased. Difference between measurements by Bland and Altman plots exceeded the current analytical quality specifications for desirable bias for WBC, RBC, hemoglobin, hematocrit, lymphocytes and monocytes in samples collected after either 1- and 3-min stasis. These results provide clear evidence that venous stasis during venipuncture might produce spurious and clinically meaningful biases in the measurement of several hematologic parameters, prompting further considerations on the usefulness of adopting appropriate preventive measures for minimizing such influences.
Abstract: INTRODUCTION: Recent investigations show that activated factor VII, the primary enzyme in the extrinsic pathway of blood coagulation, exerts additional extra-coagulant functions, such as apoptosis and angiogenesis. On the basis of these recent acquisitions, the present study was aimed to evaluate activated factor VII in patients with systemic sclerosis and to establish a potential association with pathogenesis and complications of this severe autoimmune disorder. MATERIALS AND METHODS: Activated factor VII level was measured in twenty-eight consecutive scleroderma patients (2 men and 26 women, mean age 49.7 +/- 14.8 years). The main clinical correlates of disease, such as disease activity, renal function, skin, vascular and lung involvement, were evaluated by clinical and instrumental investigations. Activated factor VII level was also evaluated in 28 sex and age matched controls. RESULTS: Systemic sclerosis patients exhibited plasma activated factor VII activities significantly lower than those of healthy matched controls (15.2 versus 37.7 U/l, respectively; p < 0.001). No correlation was observed between plasma activated factor VII concentration and age, disease duration, disease subset, disease activity, renal, lung, skin and microvascular involvement. CONCLUSIONS: Results of our investigation provide first evidence of low activated factor VII activity in patients with systemic sclerosis. Reduced activated factor VII activity might be involved in the pathogenesis of the ischemic complications, by modulating apoptotic and angiogenetic processes.
Abstract: BACKGROUND: There are controversial evidences on the effect of different types and workloads of physical exercise on primary hemostasis. In particular, little is known on the chronic influence of a strenuous and regular aerobic training regimen on platelet function. METHODS: The aim of this investigation was to compare platelet function between sedentary controls and trained athletes at rest and to evaluate whether a greater amount of exercise performed in professional cyclists may contribute to increased platelet chronic responsiveness compared to both elite cyclists and sedentary individuals. Platelet's ability to adhere and aggregate was assayed following a 12-24 h resting period in 49 active professional male road cyclists, 40 elite male cyclists and 43 matched sedentary healthy male volunteers, by the platelet function analyzer 100 (PFA-100). RESULTS AND DISCUSSION: Mean values of the collagen-epinephrine test did not differ between controls and athletes (sedentary controls: 111 +/- 33 s; elite athletes: 113 +/- 26 s, p = 0.93; professional athletes: 120 +/- 33 s; p = 0.33), whereas mean values of the collagen-ADP test displayed a slightly but significant trend towards decreased values when comparing sedentary controls (83 +/- 21 s) with either elite (77 +/- 11 s, p < 0.01) or professional (75 +/- 16 s, p < 0.01) athletes. CONCLUSION: The trend towards slightly lower collagen-ADP values are suggestive for a modest but significant chronic activation of primary hemostasis, highlighting the need to set appropriate reference ranges for the PFA-100 when evaluating primary hemostasis in physically active subjects.
Abstract: The phlebotomy technique, particularly the use of small-bore needles, may influence the reliability of coagulation testing and platelet count. Routine coagulation tests were assayed in blood specimens collected from 22 consecutive patients in three separate, sequential phlebotomies, using butterfly devices with different needle sizes. Test results of samples collected with 23 and 25 G needles were compared with those obtained with the currently recommended 21 G needle. Although both the prothrombin time and activated partial thromboplastin time displayed a trend towards lower values employing the smaller 23 and 25 G needles, results did not differ significantly from the reference 21 G needle specimen, with the exceptions of D-dimer (25 G versus 21 G needle, 186 +/- 70 versus 178 +/- 66/ml, P < 0.01) and platelet count (23 G versus 21 G needle, 246 +/- 55 versus 254 +/- 56 x 10(-3)/l, P < 0.01; 25 G versus 21 G needle, 240 +/- 55 versus 254 +/- 56 x 10(-3)/l, P < 0.01). None of the mean biases recorded for the parameters was clinically meaningful, nor did they exceed the current desirable analytical quality specifications for desirable bias. Results of the present investigation suggest that, when a proper technique is used and within certain limitations, butterfly devices with small-bore needles may be a reliable alternative to draw venous blood for platelet count and coagulation testing.
Abstract: BACKGROUND: Blood doping is commonplace in competitive athletes who seek to enhance their aerobic performances through illicit techniques. PRESENTATION OF THE HYPOTHESIS: Cobalt, a naturally-occurring element with properties similar to those of iron and nickel, induces a marked and stable polycythemic response through a more efficient transcription of the erythropoietin gene. TESTING THE HYPOTHESIS: Although little information is available so far on cobalt metabolism, reference value ranges or supplementation in athletes, there is emerging evidence that cobalt is used as a supplement and increased serum concentrations are occasionally observed in athletes. Therefore, given the athlete's connatural inclination to experiment with innovative, unfair and potentially unhealthy doping techniques, cobalt administration might soon become the most suited complement or surrogate for erythropoiesis-stimulating substances. Nevertheless, cobalt administration is not free from unsafe consequences, which involve toxic effects on heart, liver, kidney, thyroid and cancer promotion. IMPLICATIONS OF THE HYPOTHESIS: Cobalt is easily purchasable, inexpensive and not currently comprehended within the World Anti-Doping Agency prohibited list. Moreover, available techniques for measuring whole blood, serum, plasma or urinary cobalt involve analytic approaches which are currently not practical for antidoping laboratories. Thus more research on cobalt metabolism in athletes is compelling, along with implementation of effective strategies to unmask this potentially deleterious doping practice.
Abstract: Changes have occurred in the organization, complexity and role of medical laboratories in healthcare, requiring a great increase in global productivity and diagnostic efficiency by enrolled professionals to withstand new challenges. Such a radical evolution, which should be very attractive for new generations of professionals, is counterbalanced by an increasing shortage of laboratory vocations worldwide, particularly in community hospital and large reference laboratories, which may lead to a serious crisis in the field of laboratory medicine in the very near future. Some reasons can be highlighted, including the decreased interaction between clinicians and laboratory professionals, centralized testing, and the development of innovative, minimally invasive techniques that can easily be handled without direct control or supervision by laboratory staff. The prospect of a professional decline in laboratory medicine can be offset by increased awareness of the radical changes occurring within clinical laboratories and re-professionalization of laboratory scientists. This will require new resources to attract young professionals, and should include reaffirmation of the role of laboratory consultants and active participation in the development, implementation and monitoring of innovative diagnostic systems. The "patient" appears to be in a serious condition; it is in our hands to let him be reborn.
Abstract: Poor standardization of preanalytic variables exerts a strong influence on the reliability of coagulation testing, consuming valuable health care resources and compromising patient outcome. Most uncertainties emerge from patient misidentification and the procedures for specimen collection and handling. Location of unsuitable venous access or problematic phlebotomies may produce spurious activation of the hemostatic system and hemolytic specimens. Prolonged venous stasis is associated with hemoconcentration and spurious variations of most coagulation assays. Additional pitfalls can be introduced by inappropriate phlebotomy tools and small-gauge needles. Inappropriate filling and mixing of the tube, unsuitable procedures for centrifugation and storage of the specimens are additional aspects that need accurate standardization. Besides traditional preanalytic variables affecting routine coagulation testing, thrombin-generation assays require specific criteria to be accurately fulfilled. These aspects include the type of specimen (platelet-poor plasma, platelet-rich plasma or whole blood), blood collection tubes, storage conditions and the presence of residual platelets. Compliance with new international quality assessment programs, which will also involve coagulation laboratories, encompasses the adoption of suitable strategies for reducing undue variability throughout the whole testing process. Such strategies would not entail extraordinary costs and are affordable with a structured outlay of existing resources, educational policies and compliance with reliable guidelines.
Abstract: Preanalytical variability is a common source of errors in coagulation testing, as clotting assays are particularly susceptible to poor standardization of the whole analytical process. To investigate the effect of a short-term venous stasis on routine coagulation testing, we measured activated partial thromboplastin time, prothrombin time, fibrinogen and D-dimer in plasma specimens collected either without venous stasis or following the application of a 60 mmHg constant, standardized external pressure by a sphygmomanometer, for 1 (1-min stasis) and 3 min (3-min stasis). When compared with blood specimens collected without stasis, the Pearson's correlation coefficients and the corresponding slopes of the Passing and Bablok regression line of samples collected following 1 and 3-min stasis were acceptable. However, statistically significant differences by paired Student's t-test could be observed for all parameters tests following 3-min stasis, and for all but the activated partial thromboplastin time after 1-min stasis. Significant difference between specimens collected after 1- and 3-min stasis was also achieved for prothrombin time (P < 0.01), fibrinogen (P < 0.01) and D-dimer (P < 0.05). The agreement between measurements was yet acceptable after 1-min stasis, but achieved clinical significance for prothrombin time, fibrinogen and D-dimer after 3-min stasis. Taken together, results of the present investigation confirm that the effects of venous stasis during venipuncture are clinically meaningful. As hematocrit values and activities of clotting factors VII, VIII and XII significantly increased, whereas that of activated factor VII remained unchanged, we hypothesize that a short-term venous stasis, as induced by up to 3-min tourniquet placing, might not be sufficient to produce additional procoagulant responses besides hemoconcentration.
Abstract: Vigorous and prolonged physical exercise and mechanical involvement of the perineal region might influence prostatic function and measurement of both total (PSA) and free prostate specific antigen (fPSA), decreasing the diagnostic efficiency of the laboratory screening for either benign or neoplastic prostate disorders in athletes. To investigate the effects of regular and strenuous physical exercise with or without bicycle riding on integrity and biochemical function of prostatic tissue, we measured serum PSA and fPSA in 69 elite and professional cyclists, 31 members of the Italian national cross-country ski team, and in 43 sedentary healthy controls. The concentration of both PSA and fPSA did not differ significantly between sedentary individuals and physically active cross-country skiers (PSA 0.43 +/- 0.30 vs. 0.36+/-0.25, ns; fPSA 0.16+/-0.12 vs. 0.12+/-0.12, ns) or cyclists (PSA 0.43 +/- 0.30 vs. 0.36 +/- 0.23, ns; fPSA 0.16 +/- 0.12 vs. 0.13 +/- 0.08, ns), and the relative distribution of values appeared almost overlapping. We hypothesize that neither a heavy and regular physical exercise nor the extensive and prolonged mechanical involvement of the prostate region by the bicycle riding have significant influence on release of both PSA and fPSA.
Abstract: Cardiovascular disorders and acute coronary syndrome represent the leading pathologies in western countries. Over 30 years from the first diagnostic criteria issued by the World Health Organization, the diagnostic approach to patients with non-traumatic chest pain is as yet challenging. Investigators have attempted various diagnostic strategies, such as clinical decision algorithms, cardiac biomarkers, echocardiography, and myocardial perfusion imaging to avoid missing patients with myocardial ischemia or unstable angina. Although the pivotal role of cardiac troponins has now been widely recognized in the clinical management of myocardial ischemia, several patients with acute coronary syndrome might present with nondiagnostic concentrations on admission. The appropriate utilization of economical and therapeutical resources largely depends on early risk stratification, to either rule out or diagnose acute coronary syndromes, and early markers of myocardial ischemia and reliable prognostic indicators should now support investigative strategies. The ischemia-modified albumin and the brain natriuretic peptides have been recently proposed as promising markers for the early stratification of risk and prognosis. If reliable studies will confirm their suitability for evaluating patients presenting with acute coronary syndrome, a novel diagnostic approach might issue.
Abstract: OBJECTIVES: Beyond hematological manipulation, iron supplementation therapy is commonplace in athletes to counterbalance physiological or pathologic anemia and to prevent physiologic dysfunction. However, misuse of iron therapy, occasionally resulting in iron overload, is not free from metabolic risks. DESIGN: We planned to measure baseline serum ferritin concentration in sedentary individual and athletes. SETTING: The Institute of Clinical Biochemistry of the Verona University. PARTICIPANTS Serum ferritin was measured in 60 male healthy sedentary controls, 80 amateur road cyclists, 42 male professional cross-country skiers, and 88 professional male road cyclists. ASSESSMENT OF RISK FACTORS: The biochemical iron overload was ascertained by measuring baseline serum ferritin concentration as a reliable approach that mirrors the total body iron content. MAIN OUTCOME MEASUREMENTS: The concentration of serum ferritin in healthy controls was 112 +/- 78 ng/mL, whereas that of amateur cyclists, professional skiers, and professional cyclists was 127 +/- 76 ng/mL (P = 0.185), 183 +/- 130 ng/mL (P = 0.001), and 332 +/- 218 ng/mL (P < 0.001), respectively. RESULTS: Both categories of professional athletes showed significantly increased concentrations of serum ferritin, whereas the concentration of amateur cyclists was comparable to that of healthy sedentary controls. CONCLUSIONS: Professional endurance athletes have serum ferritin concentrations that are 2-fold to 3-fold higher than those of matched sedentary individuals and amateur athletes, exceeding the threshold for the diagnosis of biochemical iron overload and unveiling potential metabolic risks.
Abstract: The predominant technique used to draw blood for laboratory testing is a conventional straight needle attached to an evacuated tube system. However, alternative tools might be advantageous in exceptional circumstances. The use of butterfly devices has been traditionally discouraged for reasons of costs and due to the high risk of obtaining unsuitable samples, but there is no convincing evidence to support the latter indication. The purpose of this study was to compare results of hematological and clinical chemistry testing, after drawing blood into evacuated tubes, employing either a traditional 21-gauge straight needle or a 21-gauge butterfly device with 300-mm-grade polyvinyl chloride tubing. Blood samples and complete sets of data were successfully obtained for 30 consecutive outpatients. Of the 43 hematological and clinical chemistry parameters measured, means for paired samples collected by the two alternative drawing techniques did not differ significantly, except for serum sodium, white blood cells and platelets counts. Bland-Altman plots and limits-of-agreement analysis showed mean bias of between -7.2% and 1.7% and relative coefficients of variation ranging from 0.2% to 21.2%. The 95% agreement interval in the set of differences was acceptable and was mostly within the current analytical quality specifications for desirable bias. The rate of hemolysis in plasma was not statistically different between the two collection techniques. Taken together, the results of the present investigation suggest that, when a proper technique is used and within certain limitations, the butterfly device may be a reliable alternative to the conventional straight needle to draw blood for laboratory testing.
Abstract: Delayed sample analysis is not a rare circumstance in clinical and laboratory practice, especially when blood samples are shipped to distant centralized laboratories, when the analysis can not be readily performed, or when retesting is appropriate. In this study we sought to evaluate the stability of conventional and new hematologic parameters in blood specimens stored for as long as 24 hours at 4 degrees C. Of the 21 hematologic parameters tested with the use of the Advia 120 hematologic analyzer (Bayer Diagnostics), means for paired samples of specimens differed significantly over the 24-hour storage period for hematocrit, main corpuscular volume, percentage of macrocytes, platelet count, main platelet volume, reticulocyte count and percentage, and reticulocyte hemoglobin content (all P < .01). We noted no significant changes in the other parameters tested or in the white blood cell differential. The overall distribution of the immature reticulocytes fractions remained substantially unchanged, though the high staining-intensity fraction showed a considerable shift from the baseline measure. Bland-Altman plots and limits-of-agreement analysis showed mean biases between -4.8% and 37.2% and relative coefficients of variations ranging from 0.4% to 32.7%. The 95% agreement interval in the set of differences was satisfactory and almost within the current analytic-quality specifications for desirable bias. The results of this investigation suggest that, within certain limitations for parameters derived or calculated from cellular volumes, blood specimens stored for as long as 24 hours at 4 degrees C may be suitable for hematologic testing.
Abstract: The preoperative laboratory screening is commonplace in clinical practice and is traditionally defined as the practice of prescribing laboratory testing before surgery on patients undergoing a given procedure. The wide heterogeneity of the solutions prospected over the past decades emphasizes the objective difficulty at issuing definitive guidelines and recommendations. Despite its widespread use, a systematic evaluation of the clinical and cost-effectiveness of routine laboratory testing demonstrates that several approaches are as yet unsuitable, as inappropriate investigations may lead to evaluation of borderline or false-positive laboratory abnormalities. Three major difficulties can be identified when issuing reliable recommendations: articulation and appropriateness of diagnostic protocols, contestualization, in terms of surgical procedures and suitable clinical contests that might achieve the greatest advantages from results of laboratory testing, and impact of these tests on clinical management and outcome. This article aims to provide a comprehensive review of the current literature on this topic, attempting to suggest a suitable approach to the puzzling issue of preoperative laboratory testing.
Abstract: The measurement of cardiac troponins has emerged as the biochemical "gold standard" for the diagnosis and management of patients with acute chest pain. However, earlier markers should support investigation strategies, as several patients with acute coronary syndrome might present with non-diagnostic concentrations. Ischemia-modified albumin (IMA), measured by the albumin cobalt binding (ACB) assay, was recently proposed for early detection of myocardial ischemia. To establish the potential influence of endurance training on the diagnostic approach to patients with suspected myocardial injury, cardiac troponin T (cTnT), creatine kinase isoenzyme MB (CK-MB), myoglobin and IMA were evaluated in healthy individuals subjected to different aerobic workloads. The concentrations of both IMA and CK-MB were significantly increased in athletes subjected to high-workload endurance training, whereas the concentration of cTnT and myoglobin was not influenced by physical exercise in the medium term. Taken together, our results demonstrate that demanding aerobic physical activity might influence the generation of IMA, which might be increased in the medium term following high-workload endurance training, while the concentration of other conventional markers of myocardial injury remains non-diagnostic.
Abstract: Control and standardization of preanalytical variability is a critical factor for achieving accuracy and precision in laboratory testing. Although venous stasis from tourniquet placement during venepuncture should be minimized, as it has been claimed to account for spurious and significant variations for several analytes in plasma, there is controversy surrounding its real impact on laboratory testing. The aim of the present study was the investigation of the influence of short-term venous stasis on routine biochemical testing, by measuring the plasma concentration of 12 common analytes, including proteins, protein-bound substances, enzymes and electrolytes, in plasma specimens collected either without venous stasis or following the application of standardized external pressure of 60 mm Hg using a sphygmomanometer for 1 and 3 min. Although the overall correlation between measures was acceptable, the pattern of change was mostly dependent on the length of stasis, size and protein-binding characteristics of the analytes, achieving clinical significance for albumin, calcium and potassium after 1-min stasis, and alanine aminotransferase, albumin, calcium, chloride, total cholesterol, glucose and potassium after 3-min stasis. Statistically significant differences could be observed in seven (alanine aminotransferase, albumin, calcium, total cholesterol, creatine kinase, iron and potassium) and ten (alanine aminotransferase, albumin, calcium, chloride, total cholesterol, creatine kinase, creatinine, glucose, iron and potassium) out of the 12 analytes tested, after 1- and 3-min venous stasis, respectively. The most clinically significant changes from standard venepuncture, when compared to the current analytical quality specifications for desirable bias, occurred for potassium (1-min stasis, -2.8%; 3-min stasis, -4.8%, both p<0.001), calcium (1-min stasis, +1.6%, p<0.05; 3-min stasis, +3.6%, p<0.001) and albumin (1-min stasis, +3.5%; 3-min stasis, +8.6%, both p<0.001). As most of these effects are dependent on the stasis time during venepuncture and biochemical or physiological characteristics of the analyte, these variations could likely be anticipated, allowing the most appropriate preventive measures to be adopted.
Abstract: Blood doping is an illegal and unfair way of enhancing athletic performance by increasing the oxygen carrying capacity of the blood. Currently used methods usually involve stimulation of erythropoiesis. Gene therapy targeting the hypoxia inducible factor pathway may be an attractive alternative to traditional blood doping techniques. Hypoxia activates a large number of genes with essential roles in cell and tissue adaptation to low oxygen. Cobalt chloride is a well established chemical inducer of hypoxia-like responses such as erythropoiesis. Cobalt supplementation is not banned and therefore would not be detected by current anti-doping testing. Although there is as yet no direct or anecdotal evidence of cobalt chloride administration to athletes, its use should be warned against as being not only unfair but potentially dangerous.
Abstract: Owing to a widespread diffusion, the consumption of banned and potentially harmful substances in sports has become a problem for the public health. Current estimations of the prevalence of doping in sports are rather uncertain, as most investigative tools do not reflect an absolute statistical power. However, the emerging scenario reflects a concerning underestimation by Structures and Institutions that should establish definitive rules and set reliable controls. Owing to restricted resources, prevention and fight against doping must be supported by meditated and rational strategies, with the aim to identify suitable contests and accurate procedures, considering carefully ethical issues that may arise from the positivity of the athletes to antidoping controls.
Abstract: Owing to considerable physical, endocrinological and metabolic adaptations, the analysis of biochemical data in elite and top-class athletes requires caution. With the aim to identify metabolic and biochemical adaptations to particular lifestyle conditions, such as regular and strenuous physical exercise, we measured the concentration of serum albumin, creatinine, uric acid and glucose in 80 male professional cyclists, 37 male members of the Italian national cross-country ski team and 60 male healthy sedentary controls at rest. At variance with earlier investigations, endurance athletes showed significantly decreased concentrations of serum creatinine (controls: 83.1+/-11.0 micromol/l; skiers: 78.0+/-8.4 micromol/l; p<0.05; cyclists: 73.8+/-10.4 micromol/l; p<0.01), uric acid (controls: 362+/-69 micromol/l; skiers: 331 +/-70 micromol/l; p<0.05; cyclists: 312+/-61 micromol/l; p<0.01) and glucose (controls: 5.35+/-0.54 mmol/l; skiers: 4.94+/-0.41 mmol/l; p<0.01; cyclists: 4.94+/-0.42 mmol/l; p<0.01). The concentration of serum albumin was also decreased in athletes, but the difference did not reach statistical significance (controls: 4.76+/-0.26 g/l; skiers: 4.71+/-0.22 g/l; p=0.384; cyclists: 4.68+/-0.22 g/l; p=0.393). Results of the present investigation demonstrate that values of laboratory testing lying outside conventional reference limits calculated on sedentary populations might express physiological adaptations to regular and demanding physical aerobic activity, emphasizing the need for the estimation of reliable reference limits in elite and professional athletes, to avoid equivocal interpretation of results within clinical and anti-doping contests.
Abstract: Lipoprotein(a) is a cholesterol-enriched lipoprotein, consisting of a covalent linkage joining the unique and highly polymorphic apolipoprotein(a) to apolipoprotein B100, the main protein moiety of low-density lipoproteins. Although the concentration of lipoprotein(a) in humans is mostly genetically determined, acquired disorders might influence synthesis and catabolism of the particle. Raised concentration of lipoprotein(a) has been acknowledged as a leading inherited risk factor for both premature and advanced atherosclerosis at different vascular sites. The strong structural homologies with plasminogen and low-density lipoproteins suggest that lipoprotein(a) might represent the ideal bridge between the fields of atherosclerosis and thrombosis in the pathogenesis of vascular occlusive disorders. Unfortunately, the exact mechanisms by which lipoprotein(a) promotes, accelerates, and complicates atherosclerosis are only partially understood. In some clinical settings, such as in patients at exceptionally low risk for cardiovascular disease, the potential regenerative and antineoplastic properties of lipoprotein(a) might paradoxically counterbalance its athero-thrombogenicity, as attested by the compatibility between raised plasma lipoprotein(a) levels and longevity.
Abstract: Although the use of oral contraceptives has been frequently associated with an increased risk of thromboembolic events, definitive prothrombotic mechanisms have not so far been fully elucidated. The aim of our investigation was the evaluation of the activities of antithrombin, protein C, protein S and the resistance to activated protein C in 137 healthy users of third-generation oral contraceptives and in 170 healthy women who were not consuming oral contraceptives. Women on oral contraceptives showed a marked prothrombotic pattern, characterized by reduced activities of antithrombin and protein S, and increased resistance to activated protein C. Nearby 50% of oral contraceptive users displayed activities of protein S below the lower value of the reference range (controls, 10%; P < 0.001). No significant differences were observed between two progestagens (desogestrel or gestodene) on the coagulation parameters tested. We believe that, due to the adverse effect on haemostasis, the administration of third-generation oral contraceptives should be carefully considered in women carrying prothrombotic abnormalities.
Abstract: BACKGROUND: Patients with chronic renal failure on maintenance haemodialysis (HD) are at high risk of atherothrombotic events; an enhanced oxidant stress might have a major role. The decrease of human paraoxonase (PON1), an anti-oxidant high-density lipoprotein (HDL)-linked enzyme, is a possible mechanism for developing cardiovascular disease. To ascertain the causes of low PON1 in such patients, we investigated the contribution of both PON1 gene polymorphism and individual pattern of HDL. METHODS: On 74 HD patients (47 M and 27 F) and on 92 healthy individuals (HS, 48 M and 44 F), we studied PON1 activity, PON1 genotype (55 and 192 PON1 allelic polymorphisms) and the lipid profile, including the HDL subfractions. RESULTS: We observed in HD patients the following significant differences: (1) decreased median PON1 activity (73.5 vs. 110 U/l); (2) decreased mean HDL concentration (1.05 +/- 0.18 vs. 1.55 +/- 0.41 mmol/l); (3) decreased mean HDL3 concentration (0.79 +/- 0.21 vs. 1.28 +/- 0.24 mmol/l). Total HDL retained about 70% of serum activity, almost completely carried (95%) by the HDL3. Finally, PON1 activity remained significantly low in HD vs. HS after matching for the allelic polymorphism. CONCLUSIONS: The reduction of the HDL3, not the genetic PON1 polymorphism, seems the most important determinant of PON1 activity reduction in HD.
Abstract: The progressive increase of deaths and morbidity from cardiovascular disease (CVD) in most developed societies has led to the formulation of preventive strategies and application of several diagnostic guidelines. However, there is emerging evidence that most panels and algorithms are inadequate and require urgent revision and updating. Therefore, the aim of this study was the evaluation of a wide cardiovascular risk profile in elderly male patients with acute myocardial infarction (AMI) or peripheral occlusive disease (POD). The risk profile was assessed by measuring conventional serum lipid and lipoprotein levels and emerging parameters: lipoprotein(a) (Lp[a]), homocysteine (Hcy), and C-reactive protein (CRP). The concentration of triglycerides, Lp(a), Hcy and the total cholesterol/high-density lipoprotein (TC/HDL) ratio were significantly higher in both classes of patients than in a population of matched healthy controls and, similarly, patients with CVD displayed lower plasma values of HDL. No significant differences were observed for TC, low-density lipoprotein (LDL), and CRP. Patients with POD exhibited a marked atherogenic profile, as attested by substantially increased values of Hcy, Lp(a), triglycerides, and TC/HDL ratio. The frequency distributions of Lp(a) and Hcy concentrations were markedly shifted toward upper values in both classes of patients than in controls. In multivariate regression analysis, Lp(a) and Hcy were the best predictors for AMI, whereas Lp(a), Hcy, and the TC/HDL ratio were the best predictors for POD. Taken together, these data suggest that Lp(a) and Hcy excesses might exert a central role in the development of atherosclerotic disease in elderly male patients. Thereby, the inclusion of those tests, along with the TC/HDL ratio and other more conventional analyses in panels for the evaluation of the cardiovascular risk might be profitable in terms of effectual prevention.
Abstract: The prognosis of venous thromboembolism is considerably influenced by an accurate and fast diagnosis. Although the role of D-dimer testing in the diagnosis of suspected venous thromboembolism is well established for outpatients, there is controversial evidence on the clinical usefulness of its measurement in surgical patients. In order to recognize patterns of variation of D-dimer following surgery and identify potential pitfalls in prediction of venous thromboembolic complications, plasma D-dimer was assayed in 30 patients undergoing major elective hip surgery and 20 patients undergoing laparoscopic cholecystectomy for acute cholecystitis. The postoperative variation of plasma D-dimer differed widely between the two subgroups. Patients undergoing laparoscopic cholecystectomy showed D-dimer concentrations persistently increased from the baseline to the 15th postoperative day, whereas patients undergoing hip surgery were characterized by a double peak, on the 1st and 7th postoperative days. Mean inter-individual daily coefficient of variations of plasma D-dimer throughout the postoperative period were 49% (range 39%-61%) for laparoscopic cholecystectomy and 101% (range 72%-156%) for orthopedic surgery. The markedly heterogeneous fluctuation of plasma D-dimer suggests that the postoperative activation of the hemostatic system depends on the type and time since surgery, thus limiting the clinical usefulness of D-dimer testing in the diagnostic approach to postoperative venous thromboembolism.
Abstract: We review current concepts regarding the genetic, structural and metabolic features of lipoprotein(a), a major inherited cardiovascular pathogen. Although lipoprotein(a) is almost completely confined to a subset of primates, the hedgehog produces a lipoprotein(a)-like complex, which appears to have evolved independently from that of humans. The physiological role of lipoprotein(a) in humans is still unclear, and individuals with low or null concentrations of plasma lipoprotein(a) manifest no deficiency syndrome or disease. The integration of recent discoveries about the structure and metabolism of this unique lipoprotein particle has allowed the formulation of some hypotheses concerning the evolutionary advantages of synthesizing lipoprotein(a)-like particles.
Abstract: Nowadays, bisphosphonates are considered the drugs of choice for the treatment of several bone disorders. Their exact mechanism of action is not clear but recently it has been reported that the aminobisphosphonates inhibit cholesterol biosynthesis and that this might be relevant for their actions on bone osteoclasts. The study includes 87 postmenopausal women with moderate to severe osteoporosis. The patients were randomly assigned to intravenous (iv) infusion of 50 mg of the aminobisphosphonate Neridronate dissolved in 100 ml of saline solution every 2 months for a year (44 patients). The remaining 43 served as controls. At the time of each infusion blood samples were obtained for the evaluation of total cholesterol, triglycerides, high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C), apolipoprotein A-I (Apo A-I), apolipoprotein B (Apo B), and total and bone alkaline phosphatase (AP). Free deoxypyridinoline (f-DPD) was measured in fasting urine specimens. In the control group no significant changes were observed throughout the study period for any of the biochemical variables. In the Neridronate-treated patients both bone AP and f-DPD excretion fell significantly by 15-20%. In these patients serum total cholesterol and serum triglycerides showed marginal decreases, which were occasionally significant. LDL-C and Apo B fell by 5-6% and these changes were statistically significant at most time points. Apo A-I and HDL-C rose progressively with time. At the 12th month, HDL-C rose 17-18% (p < 0.0001) above the baseline values. Similar findings were obtained in four postmenopausal women given high iv doses of Pamidronate or Alendronate. In conclusion aminobisphophonates, at least when given iv, induce remarkable and unexpected effects on lipid metabolism with a final profile that might be clinically relevant.
Abstract: The growing diffusion of banned practice to improve the athletic performances is forcing clinical laboratories to identify and standardize reliable assays to detect potential unfairness. Among the doping practices, the use of recombinant human erythropoietin is becoming fairly popular, due to simplicity and safeties of administration and troublesome detection. The heterogeneous response rate, the presence of a little but significant amount of naturally occurring hormone, the short half-life exhibited by recombinant human erythropoietin and the lack of standardization of commercial assays appear the main problems to overcome. Aim of the present article is to provide a critical review of some of the more widespread laboratory techniques currently available for the screening for erythropoietin abuse in sport.
Abstract: Lipoprotein(a) (Lp(a)) is a genetic variant of low density lipoproteins and consists of the covalent association of the unique and enigmatic apolipoprotein(a) to apoliprotein B100. Despite the high degree of homology with low density lipoproteins, Lp(a) displays distinctive physico-chemical properties, function and metabolism. The present article reviews the main biological and clinical evidences about the association between raised concentration of Lp(a) and atherothrombotic diseases and provides tentative guidelines to improve the clinical usefulness of Lp(a) measurements.
Abstract: Doping is widely known as the use of banned substances and practices by athletes in an attempt to improve sporting performances. The term doping likely derives from "dope", an ancient expression referred to a primitive alcoholic drink that was used as a stimulant in South African ceremonial dances; gradually, the term was extended and finally adopted his current significance. There are at least two essential reasons to support the fight against doping: the potential harmful effects on athletes and the depth corruption of the fair competition. An exhaustive list of banned substances and methods has been drawn by the International Olympic Committee and further accepted by other International Sport Authorities and Federations. This list, regularly updated, is basically divided into doping substances (stimulants, narcotic analgesics, anabolic agents, diuretics, peptide and glycoprotein hormones and analogues), doping methods (blood doping, pharmacological, chemical and physical manipulation) and drugs subjected to certain restrictions (alcohol, marijuana, local anesthetics, corticosteroids and beta-blockers). Although there might be some medical conditions, which could legitimate the need of these substances or methods, there is no place for their use in sport. Thus, an athlete's consume of any of these substances or methods will result in disqualification. Aim of the present review is to provide a synthetic description of both the desirable effects and the potentially harmful consequences of the use of some of the major doping substances and methods.
Abstract: Selenium is an essential component of glutathione peroxidase enzymes, which protect cells against peroxidation and control concentrations of intracellular proxides. Since selenium deficiency is associated with an increased incidence of arterial thrombosis, we studied the effect of selenium on in vitro interactions between platelets and endothelial cells. Platelets from normal volunteers on a diet with (PLTSe+) or without (PLTSe-) selenium supplementation and human umbilical vein endothelial cells cultured in medium alone (ECSe-) or supplemented with Se (ECSe+) were used. The effect of in vivo administration or in vitro supplementation of selenium on platelet function was investigated in an aggregometry model designed for studying the interactions between platelets and endothelial cells using ADP and arachidonic acid as agonists. We observed that: (1) selenium-dependent glutathione peroxidase enzyme activity increased in both PLTSe+ and ECSe+, being about fivefold higher in the former; (2) platelet aggregation was inhibited by Se+ cells; (3) Se+ cells released less thromboxane B(2) (PLTSe+) and more 6-keto-prostaglandin F(1alpha) (ECSe+) than Se- cells; (4) when ECSe+ were treated with acetylsalicylic acid, the inhibitory effect of selenium on platelet aggregation disappeared; (5) the concentration of nitric oxide metabolites in Se+ culture media did not differ from that in Se- media. We suggest that an antithrombotic effect on the interactions between platelets and endothelial cells can be induced by stimulating glutathione peroxidase enzymes with selenium via a mechanism that is blocked by acetylsalicylic acid and is apparently unrelated to the biosynthesis of nitric oxide metabolites.
Abstract: BACKGROUND AND OBJECTIVE: Lipoprotein(a) is an LDL-like particle displaying strong athero-thrombotic properties. Although Lp(a) plays a pivotal role in the genesis and progression of thrombosis in the arterial district, its role in promoting thrombosis in the venous district is still unclear. DESIGN AND METHODS: To give further insight into the thrombotic potential of Lp(a), 100 potentially eligible consecutive outpatients who had suffered from previous episodes of venous thrombosis (deep vein thrombosis with or without pulmonary embolism) were enrolled into the study. Thirty-six of these patients who did not fulfil the entry criteria were then excluded from the study. The concentration of Lp(a) was thus measured in 64 patients, and compared to that of 64 control subjects, matched for sex (p=0.46), age (p=0.25) and pharmacological treatment; no subject belonging to the control group had a familial or personal history of venous thromboembolism. Exclusion criteria for both groups included: diabetes mellitus, liver or kidney diseases and malignancy, as established by both laboratory analysis and physical examination. To rule out false elevations of Lp(a) due to the presence of a concurrent acute phase response, C reactive protein (CRP) was measured in both groups using a commercial immunonephelometric assay. RESULTS: No statistically significant differences were observed in the median Lp(a) concentration between patients and controls (median: 69 vs 83 mg/L, respectively; p=0.34). Neither were any significant differences found between patients who had suffered from deep venous thrombosis with (n=18) or without (n=46) pulmonary embolism (median: 73 vs 69 mg/L, respectively; p=0. 83). The concentration of CRP did not differ significantly between cases and controls (median: 1.8 vs 2.3 g/L, respectively; p=0.37). INTERPRETATION AND CONCLUSIONS: Although there are several plausible biological mechanisms to explain the strong thrombogenicity of Lp(a) in vitro, we failed to demonstrate a convincing association between Lp(a) and thrombosis in the venous district. Besides the proven prothrombotic role of Lp(a) in some selected clinical settings, it is thus conceivable that the contribution of Lp(a) to genesis and progression of the venous thrombosis might be marginal or efficiently counterbalanced in vivo. The clinical usefulness of including the measurement of Lp(a) among the screening tests for thrombophilic patients, therefore, remains questionable.
Abstract: The present article proposes personal suggestions to improve determinations and clinical interpretation of results of lipoprotein(a) assays. Methods and procedures for sampling and quantification of the various isoforms of lipoprotein(a) in serum, plasma and urine are reviewed with the aim of improving the reliability and reproducibility of results and reinforcing the clinical utility of lipoprotein(a) measurements.
Abstract: Lipoprotein(a) (Lp(a)) is a low density lipoprotein-like particle displaying strong atherothrombotic properties. Although the concentration of Lp(a) in plasma is under strong genetic regulation, there are emerging evidences that several other factors, such as hormonal disorders, acute phase, liver and renal failure may affect its metabolism. The aim of the present study was to investigate whether bisphosphonates, an effectual drug in the treatment of malignant hypercalcemia and Paget's disease of bone, known to induce a concomitant acute phase, may have a significant influence on Lp(a) concentrations. Nine subjects (four men and five women), with plasma Lp(a) concentrations in the range between 6.4 and 17.7 mg/dl, were subjected to a single intravenous infusion of bisphosphonates (7.5 mg of aminohydroxybutylidene and 5.0 mg of aminohydroxylidene), previously dissolved in 250 ml of saline. Lp(a), apo A-I, apo B, C reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were measured at the baseline and after days one, two, four and seven. CRP, ESR and Lp(a) started to increase after two days from the treatment, reaching statistical significance after day two, four and seven, respectively. Apo B and apo A-I decreased significantly after days one and two, respectively. Although patterns and relative amounts of the increase of CRP were substantially different among the subjects studied, the increase of Lp(a) was more homogeneous; the peak of Lp(a) concentrations was reached only seven days after treatment in the group as a whole, in agreement with previous observations. In univariate regression analysis, significant correlations were found only between apo A-I and ESR, and apo A-I and Lp(a). The present study suggest that Lp(a) behaves as an acute phase protein. Besides, we observed a slight but significant decrease of apo A-I and apo B after administration of bisphosphonates.
Abstract: BACKGROUND: Immunocytochemistry has been proven able to identify tumor cells in bone marrow aspirate (BMA) of patients with SCLC. However, few data exist about the clinical significance of the procedure. PATIENTS AND METHODS: 108 BMA taken from 60 patients were incubated with the MoAb MLuC1 (cluster 6) and stained by the APAAP (alkaline phosphatase-antialkaline phosphatase) method. The serum levels of LDH, TPA, NSE and CEA were also studied in relation to bone marrow involvement by means of discriminant analysis. RESULTS: Immunocytochemistry of the aspirate with MLuC1 detected positive cells in 23 patients (38%) (38 of 108 samples) vs. 13% of the conventional biopsies studied without MLuC1 (P < 0.001). With respect to bone marrow positivity, three groups of patients were identified: those with no positive cells in the aspirate and negative biopsy (group A); those with less than 10 positive cells in the aspirate and negative biopsy (group B); and those with more than 10 positive cells or clumps in the aspirate or positive biopsy (group C). Group C patients had poorer median survivals than those in the other two groups (5.5 vs. 11 months, respectively, P = 0.01). Discriminant analysis showed that the four serum markers were poor discriminators of the degree of bone marrow involvement, with only 55% of grouped cases being correctly classified. CONCLUSIONS: These results show that detection of bone marrow involvement i) can be improved by the use of MLuC1 ii) is not predictable by conventional tumor markers, and iii) is related to poor outcome.
Abstract: The effect of pyridoxal 5'-phosphate (PP) on human polymorphonuclear leukocytes respiratory burst and on cellular adhesion on serum coated microplates was investigated. No dose-response effect was observed after 10 min pre-treatment at 37 degrees C of human neutrophils with increasing doses of PP, ranging from 0.05 mM/L to 0.5 mM/L. The production of superoxide anion (O2-), after challenging cells with 0.5 pM/L formyl-methyonyl-leucyl-phenylalanine, 50 ng/mL phorbol myristate acetate or 50 pg/mL concanavalin A was comparable to that observed by pre-treating cells with phosphate buffered saline only (control, no PP), therefore indicating that PP did not affect neutrophil respiratory burst in our assay conditions. Evaluation of the effect on cellular adhesion onto fetal bovine serum pre-coated microplates produced the same results. As previous results showed that PP in the range of 0.01 mM/L to 0.6 mM/L proved to be an efficient inhibitor of neutrophil aggregation, the evidence reported here might contribute to establish PP as a good in vitro leukocyte anti-aggregant which does not affect other functional parameters.
Abstract: The study was designed to establish the usefulness of measuring lipoprotein(a) [Lp(a)], total cholesterol, triglycerides, low-density lipoprotein [LDL]-cholesterol, high-density lipoprotein [HDL]-cholesterol, total-to-HDL-cholesterol ratio and fibrinogen in identifying subjects at risk of occlusive complications following vascular and endovascular surgery, including primary successful ileofemoral percutaneous transluminal angioplasty, infrainguinal and aortic bypass graft and carotid endarterectomy. A total of 68 volunteers subjected to vascular and endovascular surgery were recruited to the study. Six months after successful interventions, no occlusive complications verified by angiography were observed in 45 patients (66%; No-restenosis group), whereas significant restenosis or reocclusion occurred in 23 patients (34%; Restenosis group). Significant lower concentrations of Lp(a) (p=0.032), total cholesterol (p<0.0001), LDL-cholesterol (p=0.001) and total-to-HDL-cholesterol ratio (p<0.0001) and higher concentrations of HDL-cholesterol (p=0.048) were observed in the No-restenosis group compared to the Restenosis group. The concentrations of triglycerides (p=0.080) and fibrinogen (p=0.510) did not differ significantly between groups. In multivariate discriminant analysis, the best predictors of restenosis or reocclusion were in decreasing order: LDL-cholesterol, Lp(a), total-to-HDL-cholesterol ratio, HDL-cholesterol and total cholesterol. A statistical difference of particular interest was observed in the overall distribution of Lp(a) concentrations between groups (p<0.0001), occlusive complications being unlikely to occur in patients with Lp(a) concentrations below 50 mg L(-1). The potential interference from a concurrent acute phase response, the most common source of elevation of Lp(a) in humans, was less likely in view of the absence of differences in erythrocyte sedimentation rate between the No-restenosis and Restenosis groups (p=0.463). In conclusion, the results of the present investigation point to a definite role of the combined measurements LDL-cholesterol, Lp(a), total-to-HDL-cholesterol ratio, HDL-cholesterol and total cholesterol in the identification of subjects at risk of occlusive events following vascular and endovascular surgical procedures.
Abstract: Several commercial methods have been proposed for lipoprotein(a) (Lp(a)) measurements over the past decades. However, only a few of them appear completely suitable in terms of analytical performance, costs and practicability. We evaluated the analytical performance of a new commercial fully automated immunonephelometric assay for Lp(a) measurements on the IMMAGE Immunochemistry System. Mean within- and between-run coefficients of variation were 2.7% (range 1.2-4.7%) and 3.8% (range 1.8-7.9%), respectively. The linearity of the assay was confirmed up to 102 mg/dl and the deviation from the expected values did not exceed 4% (mean deviation: 1.9%). Moreover, the relative non-linearity was acceptable, ranging from 1.4% to 1.6% and hence constantly lower than the 2.5% upper limit. Since there is no reference method for Lp(a) measurements, 100 routine random serum samples measured by the IMMAGE Immunochemistry System immunonephelometric assay were further compared with two other commercial immunonephelometric assays (Array LPA immunonephelometric assay and BNA Latex-Enhanced Lp(a) nephelometric assay). Non-parametric regression and relative Spearman's correlation coefficients were satisfactory, (y=1.009x - 1.38; r=0.998 IMMAGE Immunochemistry System vs. Array LPA and y=0.922x - 0.40; r=0.989 IMMAGE Immunochemistry System vs. Behring Nephelometer Analyzer (BNA) Latex Lp(a) assay). On the basis of the results of the present evaluation we conclude that the analytical performance and the main technical features of the IMMAGE Immunochemistry System immunonephelometric assay make it a suitable method for Lp(a) measurement in clinical laboratories.
Abstract: The Roche Cobas Vega is a five-part differential haematological analyzer evolving from the former Cobas Helios, Argos and Micros. As the leukocyte differential of Cobas Vega displays several interesting features, we analyzed its clinical performance and compared it either to three other commercial haematological analyzers (Technicon-Bayer H*2, Coulter STKS and Abbott CD-3500) or to the manual reference method, as described in the National Committee for Clinical Laboratory Standards (NCCLS) H20-A protocol. Within- and between-batch coefficients of variations (CVs) of the white blood cell differential were satisfactory and close, or even better than the ones reported for the other instruments: 0.81% (neutrophils), 1.87% (lymphocytes), 6.76% (monocytes), 7.73% (eosinophils) and 22.55% (basophils). The identification of abnormalities in the white blood cell differential was obtained either on the basis of the instrument-specific ranges or on the generation of one or more flags by comparison with results of the manual reference method. The Vega demonstrated remarkable performance in terms of specificity (90.0%), sensitivity (91.6%) and both positive (97.7%) and negative (69.1%) predictive values; likewise, the global efficiency was the best (90.3%) among the analyzers we evaluated. The flags generated in the presence of morphological abnormalities of the samples displayed excellent sensitivity (from 88.9% to 100%), specificity (from 93.5% to 98.3%) and satisfactory positive (from 51.1% to 66.7%) and negative (from 98.3% to 100%) predictive values. We conclude that the analytical performance of the new Cobas Vega haematological analyzer can significantly improve the identification of various haematological abnormalities as an important contribution to the accuracy is provided by the new staining for granulocytes.
Abstract: Although lipoprotein(a) (Lp(a)) concentrations are mainly regulated genetically, it has been reported that variations in sex hormone concentrations may have effects on serum Lp(a). We evaluated the effect of nandrolone decanoate, a testosterone-derived synthetic anabolic steroid, on serum Lp(a), lipids and lipoproteins in 19 postmenopausal women who were given parenteral nandrolone decanoate (Decadurabolin) once a week for 3 weeks. At the 4th week, a significant decrease was observed for total cholesterol (p = 0.003), Lp(a) (p = 0.0003), apolipoprotein A-I (apo A-I) (p < 0.0001), and high density lipoprotein-cholesterol (HDL-C) (p < 0.0001). Moreover, a significant decrease in serum albumin concentration (p = 0.002) was concomitantly observed. We conclude that the administration of nandrolone decanoate significantly affects the lipid profile of postmenopausal women, showing controversial effects in terms of cardiovascular risk.
Abstract: In the present study the analytical performances of five new liquid applications on the Roche Cobas Integra were evaluated: urea and high density lipoprotein (HDL) cholesterol in serum and glucose, creatinine and inorganic phosphorus in urine. The analytical evaluation consisted of imprecision, linearity and method comparison performed against either the actual Cobas Integra granulate applications or the corresponding methods on a Hitachi 704, according to the National Committee for Clinical Laboratory Standards protocols. Over 3700 results were obtained within 3 months. Average values of within-run and between-day coefficients of variation (CVs) were 1.15% and 1.48%, respectively, holding to a mean total CV of 2.17%. The linearity was excellent for all the five applications evaluated as the relative non-linearity was always within 1.53%, thus completely fulfilling the 2.5% upper limit. A strict correlation was observed by comparing results of 120 samples with either the corresponding granulate applications on Cobas Integra or the Hitachi reagents. Linear regression analysis of the results yielded correlation coefficients always above 0.987 and the slopes of the Passing & Bablok regression lines did not deviate by more than 7% from unity. No drift was observed over 4 hours of operations. In conclusion, the performance of these new Cobas Integra liquid applications, as demonstrated by the present study, proved them to be highly suitable for routine use in clinical laboratories.
Abstract: Paraoxonase is a high-density lipoprotein (HDL)-associated enzyme capable of hydrolysing lipid peroxides. We measured the activity of serum paraoxonase together with serum concentrations of a variety of lipid constituents--total cholesterol, high-density lipoprotein (HDL) and low-density lipoprotein (LDL), cholesterol, triglycerides, apolipoproteins A-I and B--in 60 hemodialyzed (HD) patients. We found that the paraoxonase activity was significantly reduced in HD patients compared with 64 healthy controls (mean median and interquartile values: 93, 63, 87 IU/l in HD patients and 151, 120 and 135 IU/l in controls). In patients, the trimodal frequency of distribution of paraoxonase activity showed a shift toward lower levels. The effect of NaCl on enzyme activation was more pronounced in the patient group, as compared with controls, suggesting a higher frequency of the B allozyme (more responsive to NaCl) in this population. We suggest that altered HDL subfraction, present in HD patients, may be the main cause of the widespread depression of paraoxonase. Furthermore, the higher frequency of allozyme B among HD patients might increase the risk of coronary artery disease. In conclusion, paraoxonase activity may be an adjunctive index of altered lipoprotein metabolism with important repercussions on atherosclerosis.
Abstract: Lipoprotein(a) levels in plasma are considered an independent risk factor for atherosclerosis at different sites. Although Lp(a) measurements have recently gained interest in clinical laboratories, several problems are still unresolved. A potential source of pre-analytical variability lies in the treatment of the specimens, since it has been reported that values of several lipid quantities are lower when measured in plasma instead of serum. Lp(a) was measured in serum and in EDTA-treated, heparinised and citrated plasma from 15 healthy volunteers. Four analytical methods were used: two enzyme linked immunosorbent assays [ELISA] based on a polyclonal anti-apolipoprotein(a) antibody and a polyclonal anti-apolipoprotein B antibody, respectively; and two immunonephelo-metric assays [INA] based on a N antiserum to Lp(a) and on three monoclonal antibodies adsorbed on latex particles, respectively. Our measured Lp(a) values in plasma were lower than those found in serum, in particular for EDTA-treated (anti-apolipoprotein(a) ELISA: p < 0.01, anti-apolipoprotein B ELISA: p < 0.001 and Latex enhanced INA: p < 0.001) and citrated plasma (anti-apolipoprotein(a) ELISA: p < 0.05, anti-apolipoprotein B ELISA: p < 0.001 and INA: p < 0.001). Lp(a) values measured in heparinised plasma were also lower than those found in serum, but the difference was not statistically significant.
Abstract: Lipoprotein(a) [Lp(a)] is a low-density lipoprotein-like particle displaying strong athero-thrombotic properties. Highly purified Lp(a) is increasingly requested for standardization of Lp(a) measurements and for biological studies. Several procedures have been described for Lp(a) separation and purification but none of them appear completely suitable. We present here a procedure for Lp(a) purification based on sequential elutions after lysine-Sepharose affinity chromatography. We were able to identify four distinct subspecies of Lp(a) showing different affinity to epsilon-amino groups of lysine-Sepharose, simply by modifying molarity and pH of the eluents; the fraction obtained in highly purified state represented the major form and could be eluted with 0.5 M sodium phosphate buffer (pH 4.4). Advantages of this procedure are represented by simplicity, rapidity and final yield.
Abstract: The abnormal proliferation of mesangial cells with IgA deposition in the glomeruli characterizes primitive mesangial glomerulonephritis (IgA nephropathy, IgAN); this disease reduces the normal renal parenchyma while renal function becomes progressively impaired. The possible role of selenium has never been considered in evaluating factors involved in the pathogenesis of IgAN. In this work we compared the Se status of 14 IgAN patients (8 with normal renal function, IgAN NRF; 6 with impaired renal function, IgAN IRF) to that of 14 normal individuals (CG NRF) before and after an oral supplementation with selenite (0.13 mol Se/kg b.w./day for 60 days). The following indices of Se status were measured: Se in plasma and urine samples by PIXE; glutathione peroxidase activity in the cytosol of platelets (PLTs-GSH-Px) and of erythrocytes (RBCs-GSH-Px). Both concentrations and activities of plasma glutathione peroxidase (pl-GPx), a selenoenzyme mainly synthesized in and secreted by the kidney, were measured in plasma samples and results compared among groups. IgAN patients showed lower pl-Se and lower activities of selenoenzymes than normal controls before Se supplementation (p < 0.001). These findings suggest that an impaired Se status coexisted with the proliferation of mesangial cells in patients. Selenite induced PLTs-GSH-Px activity in all individuals (p < 0.001), but no variation was observed in RBCs-GSH-Px activity or in the concentration of pl-GPx in the plasma. On the other hand, selenium induced pl-GPx activity in CG NRF (p < 0.001) and in IgAN NRF (p < 0.01), but poorly stimulated pl-GPx activity in IgAN IRF (p = n.s.). However, only 17% and 25% of the pl-GPx activity of normal controls was measured in the plasma of IgAN IRF and IgAN NRF patients, respectively (p < 0.001). In conclusion, selenite only partially restored a normal Se status in patients whose low pl-GPx activity probably reflects an impaired synthesis of this protein as a consequence of reduced normal functioning of the parenchyma in kidneys affected by IgA nephropathy.
Abstract: Despite the increasing interest in the measurements of lipoprotein(a) (Lp(a) in serum or plasma, at present there is no effective standardization for Lp(a) assays; the main problems to solve are represented either by the lack of a suitable primary standard or by the absence of a reliable and widely available reference method. A first step is hence the uniformity of calibration of different immunoassays. We calibrated three commercial immunoassays for Lp(a) (enzyme linked immunosorbent assay (ELISA), latex-enhanced immunonephelometric assay (LINA), and immunonephelometric assay (INA) with either proprietary standards or purified Lp(a) material obtained with a rapid and simple procedure. Final results of purified Lp(a) calibration were reported in terms of protein Lp(a) mass whereas we were able to quantify the exact protein concentration of our purified lipoprotein. The uniformity of the calibration of the different assays led to a significant improvement of regression slopes (from 1.88 to 0.90 ELISA vs. LINA, from 1.45 to 0.95 ELISA vs. INA and from 1.27 to 0.96 INA vs. LINA) and correlation coefficients (from 0.990 to 0.994 ELISA vs. LINA, from 0.987 to 0.990 ELISA vs. INA and from 0.985 to 0.987 INA vs. LINA). Furthermore, the significant differences among Lp(a) values obtained after calibration with proprietary standards were minimized, becoming non-significant in two out of three cases. In conclusion, we demonstrated that a better agreement of Lp(a) values obtained with different commercial assays could be simply reached by uniformity of calibration and by employing standards with values accurately measured.
Abstract: Lipoprotein(a) is considered an independent risk factor for atherosclerosis. A variety of analytical methods have been proposed for lipoprotein(a) measurement, the majority of which require dedicated instruments and are costly to perform, particularly when the aim is to screen for high lipoprotein(a) concentrations in large populations. We evaluated the sensitivity and specificity of a newly developed semi-quantitative latex method to assess its suitability for identifying subjects with high lipoprotein(a) levels. Based on clinical data, a sensitivity limit of 20 mg/dl of total lipoprotein(a) particle was selected for the latex method. Results obtained by the latex method on 204 subjects were compared with two enzyme immunoassays using two anti-apo(a) monoclonal antibodies with different specificities. In one assay, the detecting monoclonal antibody (MAb a-5) is directed against an epitope present in a variable number depending on the apo(a) size isoforms in lipoprotein(a), while the other assay the detecting monoclonal antibody (MAb a-40) is directed against an epitope present only once in lipoprotein(a) particles, irrespective of their apo(a) size. Both the latex method and the MAb a-5 assay demonstrated a 100% sensitivity, in that no false-negative results were found using the MAb a-40 assay as the gold standard. Eleven subjects (5.4%) were misclassified as false positive by MAb a-5 assay and 23 (11.3%) were misclassified by the latex method. Based on its 100% sensitivity and 89% specificity, we conclude that the lipoprotein(a) latex method is a cost-effective rapid approach for screening large populations.
Abstract: High lipoprotein(a) [Lp(a)] has been observed in patients with ischemic heart disease and cerebrovascular disease. Lp(a) is actually thought to be an independent risk factor for coronary disease. We therefore carried out a case-control study, evaluating plasma Lp(a) in 61 patients with angiographically documented peripheral arterial disease (PAD) and in 61 age- and sex-matched patients with no cardiovascular disease. General risk factors for vascular disease were also taken into account. Lp(a) was significantly higher in patients than controls (257.0 +/- 34.8 vs 146.5 +/- 23.5 mg/l p < 0.05), as were cigarette smoking, diabetes, cholesterolemia, fibrinogenemia and the waist-to-hip circumference ratio. Stepwise logistic regression analysis showed that, in addition to cigarette smoking, diabetes, cholesterol and fibrinogen, Lp(a) is a significant independent risk indicator for PAD. This result suggests that high plasma Lp(a) is associated with enhanced risk of PAD and must therefore be evaluated alongside traditional risk factors.
Abstract: The kidney is a major source of the plasma enzyme glutathione peroxidase. We measured plasma glutathione peroxidase activity in 130 patients affected with different renal diseases at various stages, and compared it with the following indices of kidney function: serum creatinine, creatinine clearance, and urinary excretion of alpha 1-microglobulin, beta 2-microglobulin, albumin and N-acetyl-beta-D-glucosaminidase. Plasma glutathione peroxidase activity appeared significantly reduced in most of the renal diseases considered, and showed a significant correlation with most of the renal function indices. Linear discriminant analysis showed that the set of indices composed of plasma glutathione peroxidase activity, serum creatinine and creatinine clearance allowed the best classification of renal diseases. During treatment with the nephrotoxic aminoglycoside, tobramycin, plasma glutathione peroxidase activity showed an early and progressive decrease. We suggest the measurement of plasma glutathione peroxidase activity as an adjunctive index for the assessment of kidney alterations.
Abstract: The kidney is probably the major site of production of the plasma enzyme glutathione peroxidase (GSHPx-P). For this study, GSHPx-P activity was determined in 40 healthy people, in 34 patients with differing degrees of renal impairment, and in hemodialysis patients from whom blood samples were withdrawn either before or after each session (18 patients) or throughout the dialysis session (27 patients). Hemodialysis patients were treated by means of different techniques (bicarbonate hemodialysis, hemodiafiltration, and acetate free biofiltration), and different membranes (cuprophane, polyacrylonitrite, and polymethylmethacrylate). The following results were obtained: 1) GSHPx-P activity was significantly decreased in renal impairment patients; 2) GSHPx-P activity negatively correlated with serum creatinine values in renal impairment patients (r = -0.55; p < 0.001); and 3) the enzyme activity slightly increased after the session in hemodialysis patients. The following conclusions can be drawn: GSHPx-P activity could be new index of renal function, because it was decreased in patients with renal failure; the decrease in GSHPx-P activity paralleled the severity of renal impairment, and was maximal in hemodialysis patients; GSHPx-P activity was slightly raised at the end of the hemodialysis session, concomitant with other enzyme activities (aspartate transaminase, alanine transaminase, and alkaline phosphatase) and total protein concentration. This seems to be attributable to the process of water loss rather than other hypothetical mechanisms, such as A) enzyme activation by either peroxide generation during blood-membrane contact, or by the removal of a hypothetical inhibitor; and B) de novo synthesis in the residual renal mass or in other sites of production.
Abstract: Selenium (Se) is an essential component of glutathione peroxidase (GSH-Px), an enzyme that protects cells by reducing intracellular peroxides. Impaired Se status and GSH-Px activity seem associated with increased risk of atherosclerotic vascular diseases. This study reports the effects of Se supplementation on GSH-Px activity, on prostacyclin (PGI2) production, on 12-hydroxy-eicosatetraenoic acid (12-HETE) levels, and on GSH-Px mRNA expression in cultured human umbilical vein endothelial cells (HUVEC). Se-enriched HUVEC showed significant increase of both GSH-Px activity and thrombin-stimulated production of PGI2 in the presence of stable concentrations of 12-HETE. On the other hand, an inverse correlation between Se concentrations in culture media and GSH-Px mRNA levels in Northern blot analysis was shown; this suggests that a major degree of regulation for GSH-Px expression by Se is most likely exerted at the posttranscriptional level. These observations may help to explain the increased incidence of atherosclerosis described in Se-deficient individuals.
Abstract: In order to assess the Se status in individuals living in the Veneto region, a series of related measurements was performed. These included plasma selenium by PIXE and glutathione-peroxidase (GSH-Px) activities in plasma, red blood cells and platelets. Individuals were either normals or people suffering from various liver diseases. Moreover, an oral supplement of sodium selenite was given to 13 patients suffering from stable chronic renal failure (CRF) in parallel to 26 normals: data on plasma GSH-Px and on serum creatinine and creatinine clearance were collected either before or after supplementation. Results were in support of a relatively low selenium status: mean +/- SD plasma Se values of normals (0.82 +/- 0.17mumol/L, n = 82) were comparable to data observed in European regions where Se deficiency was already known. Even lower values were observed in those with liver diseases. Among enzyme activities, the distribution of the data of platelet GSH-Px was in further support of low Se status in the evaluated individuals. After Se supplementation, both normals and CRF patients showed a significant increase in the creatinine clearance, reflecting an improvement of the glomerular filtration rate. We suggest that more extensive surveys of the Se status should be carried out in Italy; moreover, Se supplementation may be advisable in individuals affected with moderate impairment of renal function.
Abstract: HC II functional assays are generally preferred with respect to immunochemical assays. Nevertheless functional assays can be biased by the antithrombin III (AT III)-heparin complex activity; in fact trace amounts of heparin generally contaminate dermatan sulfate (DS) commercial preparations used as HC II reaction activators. We have employed a purified DS preparation showing these features: DS concentration 94.4%, chondroitin sulfate 5.6%, M.W. 21.4 kDa. The absence of any interference due to AT III-heparin complexes was verified in a kinetic HC II assay of some human plasma pools. The immunological inhibition of AT III by anti-AT III caused a minimal decrease (6-8%) of the reaction slope, attributable to AT III activity. Progressive increase of heparin concentration in the assay was effective only starting from 30 U/ml (the assay was carried out in the presence of polybrene to prevent any AT III activation). The reference interval (mean +/- SD) obtained from 157 normal subjects was 100.8 +/- 20.2%; there was a good correlation with immunoreactive HC II. The purified DS we have used seems suitable for routinary assays of HC II where a minimal interference due to AT III-heparin is required.
Abstract: Chemical methods of measuring nitrogen in stools are complex, unpleasant, and therefore rarely performed. Recently, near infrared reflectance (NIRA) has been suggested for stool analysis. The aim of this study was to evaluate the possible application of this method in routine faecal nitrogen measurement. Nitrogen concentration and daily output were measured in the stools of 83 patients using NIRA and, for comparison, the Kjeldahl method. Nitrogen concentration and output ranged between 0.4-2.72 g% and 0.45-8.96 g/day respectively. Correlation coefficients (r), of 0.89 and 0.97 were found between the two methods for concentration and output respectively, and similar values were found in patients on enteral nutrition. Repeated measurements from the same stool collection, requiring only a few minutes, allowed homogenisation to be avoided. NIRA seems to be an easy, fast, and reliable alternative to chemical assays of nitrogen measurement in the management of patients with digestive disorders.
Abstract: Serum and erythrocyte selenium, erythrocyte and platelet glutathione-peroxidase (GSH-Px) activities, and erythrocyte reduced glutathione (GSH) content were measured in 25 healthy adult individuals before and after daily supplementation with 20 ml of fish oil for 10 weeks. Serum-Se decreased from 0.83 +/- 0.01 mumol/l to 0.75 +/- 0.02 mumol/l (mean +/- S.E.M.) (P less than 0.01); erythrocyte-Se decreased from 4.39 +/- 0.17 nmol/g hemoglobin (Hb) to 2.83 +/- 0.15 nmol/g (P less than 0.001). GSH-Px activities increased both in erythrocytes (6.93 +/- 0.24 iu/g vs 8.18 +/- 0.27 iu/g Hb, P less than 0.01) and in platelets (69.2 +/- 2.8 iu/g vs 90.9 +/- 3.6 iu/g protein, P less than 0.001). The concentration of GSH in erythrocytes fell from 9.56 +/- 0.29 mumol/g Hb to 5.90 +/- 0.30 mumol/g Hb (P less than 0.001). The effects on plasma lipids were evident only for triglycerides (before 1.96 +/- 0.16 mmol/l, after 1.75 +/- 0.14 mmol/l, P less than 0.001). We hypothesise the enrichment of erythrocyte and platelet membranes with polyunsaturated fatty acids (PUFAs), following fish oil intake, can generate increased amounts of lipid peroxides and thus allosterically activate GSH-Px: with time this is harmful for the integrity of the enzyme molecule and Se release may result. We suggest that the Se status of individuals given PUFAs is assessed before and during intake; Se supplements should only be given when serum and/or erythrocyte Se are reduced.
Abstract: We have studied the variations induced in iron status parameters by four endurance races of different lengths. A comprehensive group of 48 healthy, non-iron deficient, endurance athletes were evaluated before and after four different cross-country and roller ski races: I = Skirollonga, roller ski race for individuals (n = 10), mean duration (MD) = 1 h 48 min; II = Marcialonga, cross-country ski race for individuals (n = 9) MD = 3 h 10 min; III = 12-h of Caldonazzo (Trento-Italy) roller ski relay race (n = 13) MD = 12 h; IV = 24-h of Pinzolo (Trento-Italy) cross-country ski relay race (n = 16) MD = 24 h. In the relays the MD includes both exercise and recovery times. Blood samples were taken before and after every race for the determination of the following haematological parameters: red blood count, haemoglobin, and packed cell volume, serum iron concentration [SI], serum ferritin concentration [FERR] and total iron binding capacity (TIBC). The results showed a constant significant increase of [FERR] after the races (+44.9% in I, +50.5% in II, +51.2% in III and +36.5% in IV, P less than 0.01) while [SI] increased only in the first two races (+28.2% in I and +19.7% in II, P less than 0.01) and showed a remarkable decrease in the longer races (-46.1% in III and -39% in IV, P less than 0.01). The TIBC increased in all the races (except II) to the same extent (range 10%-12%).(ABSTRACT TRUNCATED AT 250 WORDS)
Abstract: In human platelets the selenoenzyme glutathione peroxidase (GSH-Px) acts as a scavenger of the peroxides generated during the burst of arachidonic acid (AA) metabolism. Such a mechanism inhibits the biosynthesis of both thromboxane A2 (TXA2) and lipoxygenase products. The same mechanism is not effective on the prostacyclin (PGI2) biosynthesis from cultured endothelial cells. In order to evaluate this effect in vivo, besides in vitro, we activated the enzyme in eight normal volunteers by increasing their daily Se intake for 8 weeks, monitoring: platelet GSH-Px activity, platelet aggregation induced by AA and U 44069, and concurrent malondialdehyde (MDA) and thromboxane B2 (TXB2) production, urinary excretion of renal and systemic TXA2 and PGI2 metabolites, platelet enzyme activities of the hexose monophosphate pathway and glutathione content, platelet adenine nucleotides, bleeding time, plasma Se concentration. We found: a) progressive platelet GSH-Px activation by Se paralleling an enhancement of platelet aggregation threshold values for AA, but not for U 44069; b) concurrent inhibition of platelet biosynthesis of TXA2 both in vitro and in vivo while the biosynthesis of systemic prostacyclin was unaffected; c) a progressive increase in the bleeding time, unmodified by aspirin. In conclusion, we believe that Se-dependent GSH-Px represents a physiological mechanism regulating the biosynthesis of prostanoids with implications in platelet function and that a Se dietary supplement might be considered in the prevention of arterial thrombosis.
Abstract: This investigation was aimed at comparing a new method for measuring faecal fat excretion, carried out with a semi-automated instrument by using near infrared analysis (NIRA), with the traditional titrimetric (Van de Kamer) and gravimetric (Sobel) methods. Near infrared analysis faecal fat was assayed on the three day stool collection from 118 patients (68 chronic pancreatitis, 19 organic diseases of the gastrointestinal tract, 19 alcoholic liver disease, 12 functional gastrointestinal disorders). A strict linear correlation was found between NIRA and both the titrimetric (r = 0.928, p less than 0.0001) and the gravimetric (r = 0.971, p less than 0.0001) methods. On homogenised faeces, a mean coefficient of variation of 2.1 (SD 1.71)% was found. Before homogenisation (where a mean coefficient of variation of 7% was found) accurate results were obtained when the mean of five measurements was considered. In conclusion, the assay of faecal fat excretion by the near infrared reflessometry appears a simple, rapid and reliable method for measuring steatorrhoea.
Abstract: An automated procedure to help general practitioners in clinical diagnosis and decision making is presented. The computer-based program is conceived to process results from laboratory tests performed on outpatients, providing general practitioners with possible causes of abnormal results. When only one or two abnormal tests are observed, a series of suggestions pertinent to each abnormality is printed. When there are more abnormal test results, the program performs a more complex procedure ending with the output of some diagnostic hypotheses. Messages are also printed to focus the physician's attention to particular aspects of patient pathology that were sometimes missed or disregarded and to suggest new investigations the laboratory can perform to improve diagnostic efficiency. Moreover some advice is supplied to allow a better evaluation of particular risk conditions, as those associated with the development of coronary heart disease. The program has been recently extended with the calculation of intraindividual reference intervals. The system described has been working since 1976 and appears particularly useful when the general practitioner is faced with a number of pathological results of difficult interpretation.
Abstract: Maltose is a disaccharide consisting of 2 molecules of d-glucose which at 10% solution is isotonic with plasma but provides a caloric supply double than glucose. Its possible use in total parenteral nutrition was investigated. Two homogeneous groups of patients were infused during a 2-hour period with a 10% maltose solution at 0.2 g/kg/h and at 0.4 g/kg/h flow rate. The data collected during and at the end of infusion demonstrate that: 1) the major metabolic parameters do not undergo significant alterations after maltose infusion; 2) the infusion at 0.4/kg/h causes an osmotic diuresis that does not significantly affect the water-electrolyte balance of the patients. Nevertheless it is not possible to exclude that this condition may lead to negative side-effects in critical patients; 3) the urinary excretion of maltose and glucose is significantly higher in the group of patients with 0.4 g/kg/h infusion rate.
Abstract: Adenine nucleotides (ATP and ADP) and enzyme activities of Adenylate Kinase (AK) and Phosphoglycerate Kinase (PGK) were assayed on semen samples from normal and infertile men. In accordance with the values obtained, samples could be classified into two groups: one group with levels of either adenine nucleotides and enzymes assumed as normal; a second group with high levels of all the parameters. The latter group comprised the samples with low sperm density (less than 40 million/ml). When the samples were subdivided according to sperm motility, the above distinction into two groups appeared less evident. Moreover, comparing biochemical parameters with morphological findings some contrasts were seen. Nevertheless, we suggest comparing both biochemical and morphological data for a more detailed classification of human semen abnormalities.
Abstract: Platelet glutathione peroxidase (GSH-Px) activity was measured in 25 healthy individuals and in 25 patients affected with well-documented coronary artery stenosis. In parallel, malondialdehyde (MDA) production was assayed on platelets following stimulation with sodium arachidonate. Mean platelet GSH-Px activity was significantly reduced and mean platelet MDA production was significantly increased in the patient group. The difference observed in the GSH-Px activity might be a consequence of different nutritional habits, suggesting an impaired intake of selenium, the inorganic moiety of GSH-Px. As low GSH-Px activities in human platelets may be associated with increased MDA and thromboxane production, we hypothesize that a low enzyme activity may be a risk factor for the development of coronary artery disease.
Abstract: Catalase (CAT), glutathione-peroxidase (GSH-Px) activity and reduced glutathione content (GSH) were measured in patients who had hepatocellular carcinoma, and values compared with those of normal liver and liver adjacent to neoplastic tissue. The results showed a remarkable reduction of CAT in tumor and corresponding tumor-free tissue (P less than 0.001 and P less than 0.02, respectively). All neoplastic samples had a significant lower activity of CAT than the corresponding adjacent tumor-free tissue (P less than 0.05). The GSH-Px activity of tumor tissue also was lower than normal (P less than 0.001) but similar to that of adjacent tissue. No correlation was noted between the two enzyme activities. Glutathione content was extremely low in tumor (P less than 0.001) and even in tumor-free tissue (P less than 0.05) when compared with normal liver. In all cases the content of GSH in neoplastic tissue was lower than that of the corresponding tumor-free tissue (P less than 0.05). Whereas in normal liver the activity of GSH-Px was positively correlated with the content of GSH, in the neoplastic tissue such a relationship disappeared. All these findings suggest that the antioxidant system of hepatocellular carcinoma cell is severely impaired.
Abstract: 42 different samples of human erythrocytes were tested for glutathione-peroxidase activity (GSH-Px) in an attempt to study the inhibitory effect of Bromsulphalein (BSP). The mean activity of the enzyme was 11.90 +/- 3.61 U/g Hb, with no significant difference between males and females. BSP was used at different concentrations from 1 to 45 mM and inhibited GSH-Px activity; the inhibition curve showed a sinusoidal pattern. The major effect was obtained at 30 mM BSP when almost 65% of the initial activity was inhibited. The inhibition of GSH-Px by BSP has also been confirmed using partially purified GSH-Px obtained from human erythrocytes, as well as purified bovine GSH-Px. Some difference was noted between males and females: females may be divided into two subgroups, one with a lower and a second with a higher level of GSH-Px. 1 mM BSP increased the activity in the first group, whereas it reduced the activity in the second group. The inhibition by BSP was positively correlated with the basal value of GSH-Px and this effect was particularly evident in females (r = 0.865; p less than 0.001). The possibility that GSH-Px may be inhibited by BSP would be of some importance considering the strategic role of GSH-Px in protecting the cell from oxidative attack.
Abstract: Selenium added to the culture medium of confluent pig aortic endothelial cells caused a time-related elevation in the activity of the hydroperoxide scavenging enzyme: glutathione peroxidase. This increased activity was associated with an enhanced ability to produce prostacyclin irregardless of whether the agonist was arachidonic acid or thrombin. Since prostacyclin synthetase is believed to be irreversibly inhibited by alkyl hydroperoxides, we feel that the greater production of prostacyclin by selenium-treated cells as compared with control cells may reflect a protective effect of GSH.Px towards the synthetase enzyme. The results from this study may explain the observations made on a group of human volunteers ingesting selenium as a dietary supplement. After six weeks treatment with selenium, bleeding time in this group was prolonged suggesting an improved ability to synthesize prostacyclin as a result of selenium-dependent glutathione peroxidase activation in the vessel wall.
Abstract: We investigated the possible regulatory role of glutathione peroxidase on thromboxane formation by reducing peroxides in platelets. Experiments carried out in platelet lysates demonstrated that the burst of the arachidonate metabolism was accompanied by a simultaneous burst of hydrogen transfer from glutathione to peroxides, catalyzed by endogenous glutathione peroxidase. The burst of hydrogen transfer was partially inhibited by acetylsalicylate concurrently with the complete inhibition of malondialdehyde formation, thus suggesting that the hydrogen acceptor peroxides were derived in part from the cyclooxygenase pathway. Moreover, increasing glutathione peroxidase activity by adding purified enzyme to the incubation media decreases thromboxane formation. Intact platelets, stimulated with arachidonic acid or thrombin, produced malondialdehyde and thromboxane in amounts roughly inversely related to the endogenous glutathione peroxidase activity. In contrast, no correlation was observed between glutathione peroxidase activity and agonist-induced platelet aggregation. Our experiments suggest that in normal platelets, glutathione peroxidase controls thromboxane formation.
Abstract: A 67-year-old woman investigated because of 'myelodysplastic syndrome' was found to have a 4-fold increase in G-6-PD activity in her erythrocytes. The enzyme was partially purified and characterized. On grounds of: (a) reduced electrophoretic mobility, (b) abnormal cathodic band(s) in isoelectrofocusing, (c) increased Michaelis constant for glucose 6-phosphate, (d) abnormal thermostability, and (e) abnormal interaction with the ligand NADPH, we conclude that this is a new structural variant which we designate G-6-PD Verona. G-6-PD Verona was the sole apparent source of G-6-PD activity in the patient's erythrocytes; by contrast, the patient's fibroblasts had only normal G-6-PH (type B). The patient's haematological course terminated into acute myeloid leukaemia. We believe G-6-PD Verona was the result of a somatic mutation in an X-chromosome which took place in a haemopoietic cell clone which subsequently underwent neoplastic transformation.
Abstract: The red blood cell (RBC) glutathione peroxidase (GSH-Px) activity and routine haematological parameters were measured in 38 healthy north Italian full-term pregnant women and in their newborn infants. In 31 pairs the serum selenium concentration was also measured. Data were compared with those of 20 normal adult controls (10 males and 10 females). Newborn infants exhibited significantly lower RBC GSH-Px activity and serum selenium concentrations than adult controls. Pregnant women had serum selenium values intermediate between those of adult female controls and their newborn infants. In both the pregnant women and newborns the RBC GSH-Px activity correlated with the level of selenium in serum which suggests that the neonatal RBC GSH-Px deficiency may be partially due to insufficient availability of selenium during pregancy. Factors other than selenium concentration, e.g. hormonal and genetic, might also affect the RBC GSH-Px activity as suggested by sex differences and mother/child concordances in enzyme activity found in our cases.
Abstract: Cases showing erythrocyte glutathione peroxidase (GSH-Px) defects have been previously described. Our experiments demonstrate that a number of non genetic factors may influence the GSH-Px activity in human erythrocytes. Selenium administration in vivo was followed in four subjects by elevation in erythrocyte GSH-Px activity ranging from 30% to 1400%. Selenium operates mainly in the bone marrow erythroblasts by facilitating the synthesis of active GSH-Px molecules; experiments in vivo demonstrate that, in the youngest erythrocytes, selenium can raise the enzyme activity, but by a different mechanism. The reticulocyte GSH-Px activity appears to depend on selenium availability and may vary over a wide range. In some normal and iron deficient subjects the GSH-Px activity in the youngest erythrocyte fraction was equal or lower than that previously found in whole erythrocytes of patients affected by haemolytic anaemia. During erythrocyte life, GSH-Px activity may either diminish or increase, and these variations are inversely related to the initial GSH-Px activity in youngest cells. In vitro experiments with the addition of acetyl-phynyl-hydrazine strongly suggest that elevation of GSH-Px activity may be due to allosteric enzyme activation by activated oxygen.
Abstract: Erythrocytic glutathione-peroxidase (GSH-Px) activity and plasma selenium concentrations were measured in 14 patients: 7 with iron deficiency and 7 with raised serum iron levels. The decreased enzymatic activity in iron deficiency was confirmed. Plasma selenium was significantly lower in patients with lower serum iron; furthermore there is a significant correlation between serum iron and plasma selenium concentrations. Another correlation even more significant was found between plasma selenium and enzyme activity in all the cases we studied. These data suggests that the importance of iron for GSH-Px activity may be merely due to its relationship with selenium and that plasma selenium concentration may be of critical importance for enzyme activity.
Abstract: The red cell glutathione-peroxidase (GSH-Px) activity of 9 normal subjects is compared with that of 15 cases of iron deficiency anaemia and with 13 cases of heterozygous beta-thalassemia with the same degree of anaemia and hypochromia. 2 cases of sideroblastic anaemia with high serum iron levels were also examined. Enzymatic activity was found to be significantly decreased in iron deficiency anaemia (about 55% of normal range), while it was not affected in heterozygous beta thalassaemia and it was increased in the 2 cases of sideroblastic anaemia. Moreover, GSH-Px activity exhibited a significant correlation with serum iron levels in all the patients studied. The observed modifications in GSH-Px activity are not correlated with erythrocyte ageing because reticulocyte-poor fractions exhibited GSH-Px activity which was not significantly reduced in respect of the reticulocyte-rich ones. These data seem to suggest that iron has a crucial connection with erythrocyte GSH-Px and that the enzyme deficiency may be of some importance in explaining the decreased red cell survival observed in severe iron-deficiency anaemias.
