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aristidis tsatsakis


tsatsaka@uoc.gr

Journal articles

2010
Alexandros Zafiropoulos, Manolis Linardakis, Eugene H J M Jansen, Aristidis M Tsatsakis, Antonis Kafatos, George N Tzanakakis (2010)  Paraoxonase 1 R/Q alleles are associated with differential accumulation of saturated versus 20:5n3 fatty acid in human adipose tissue.   J Lipid Res 51: 7. 1991-2000 Jul  
Abstract: Serum paraoxonase 1 (PON1) function has been associated with human cardiovascular disease. The projected mechanism postulates interaction of PON1 with lipoproteins and insulin signaling resulting in alterations in lipid homeostasis. Recently, PON2 was shown to directly regulate triglyceride accumulation in macrophages and PON1 was detected in the interstitial space of adipocytes. The aims of the present study were a) to examine the relationship of the PON1 function with serum parameters related to lipid homeostasis, and b) to examine a possible role of PON1 in the regulation of lipid composition in the human adipose tissue. Two important genetic variations with functional impact on PON1 activity in humans are the Q192R and the L55M. The present study evaluated the impact of the Q192R and the L55M polymorphisms in a cross-section of the population on the island of Crete, as regards to PON1 activity, plasma lipids/lipoproteins, parameters of the metabolic syndrome, and the fatty acid composition of the adipose tissue. We detected a significant association of the polymorphisms with blood pressure, fasting blood glucose, triglycerides, apolipoprotein B, serum iron, and homocysteine. Furthermore, a novel function is suggested for PON1 on the fatty acid composition in the adipose tissue through the positive association of the R allele with saturated fatty acid and of the Q allele with 20:5n3 fatty acid deposition.
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Vasilis P Androutsopoulos, Athanasios Papakyriakou, Dionisios Vourloumis, Aristidis M Tsatsakis, Demetrios A Spandidos (2010)  Dietary flavonoids in cancer therapy and prevention: substrates and inhibitors of cytochrome P450 CYP1 enzymes.   Pharmacol Ther 126: 1. 9-20 Apr  
Abstract: Flavonoids are polyphenolic compounds that have attracted the attention of the scientific community as the hallmark molecules responsible for cancer prevention by a plethora of different mechanisms. One of their most important characteristics, responsible for their cancer preventive properties, is their interaction with cytochrome P450 CYP1 enzymes. Flavonoids have traditionally been described as CYP1 inhibitors due to the inhibition of carcinogenic product formation and consequent blockage of the initiation stage of carcinogenesis. However, mounting evidence indicate that flavonoids are also capable of acting as CYP1 substrates, undergoing bioactivation to more antiproliferative agents within cancer cells. In this review, a comprehensive summary of the two models is presented. Structural features responsible for CYP1 inhibition or substrate turnover are discussed and limitations as well as discrepancies between procarcinogen-activating and 7-ethoxyresorufin-inhibition assay systems are further explored in vitro and in vivo. Moreover, a thorough investigation of the substrate specificity of flavonoids for the active site of CYP1 enzymes is undertaken. Finally, issues concerning the bioavailability and metabolic fate of these compounds in vivo are addressed. Ultimately, the mode of flavonoid action, in terms of CYP1 inhibition or CYP1-mediated bioactivation, is dependent on the lipophilicity or hydrophilicity of each compound. The degree of hydroxylation or methoxylation of the A and B rings is the major factor which determines the accessibility to the tumor site, in terms of hepatic and intestinal metabolism, and the introduction of the molecules to the CYP1 active site, respectively.
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Aikaterini Berdiaki, Georgios A Datsis, Dragana Nikitovic, Aristidis Tsatsakis, Pavlos Katonis, Nikos K Karamanos, George N Tzanakakis (2010)  Parathyroid hormone (PTH) peptides through the regulation of hyaluronan metabolism affect osteosarcoma cell migration.   IUBMB Life 62: 5. 377-386 May  
Abstract: Parathyroid hormone (PTH) strongly stimulates hyaluronan (HA) synthesis and secretion of both normal and carcinogenic cells of the osteoblastic lineage and improves skeletal microarchitecture. HA, a glycosaminoglycan component of the extracellular matrix (ECM), is capable of transmitting ECM-derived signals to regulate cellular function. In this study, we investigated whether the changes of HA metabolism induced by PTH (1-34) and PTH (7-84) peptides in moderately MG-63 and well-differentiated Saos 2 osteosarcoma cell lines, are correlated to their migration capabilities. Our results demonstrate that intermittent PTH (1-34) treatment significantly (P < or = 0.01) supported the migration of MG-63 cells, increased their HA-synthase-2 (HAS2) expression (P < or = 0.001), and enhanced their high-molecular size HA deposition in the pericellular matrix. Both increased endogenous HA production (P < or = 0.01) and treatment with exogenous high-molecular weight HA (P < or = 0.05) correlated to a significant increase of MG-63 cell migration capacity. Transfection with siHAS2 showed that PTH (1-34), mainly through HAS2, enhanced HA and regulated MG-63 cell motility. Interestingly, continuous PTH (1-34) treatment stimulated both Saos 2 cell HAS2 (P < or = 0.001) and HAS1 (P < or = 0.001) isoform expression inhibited their HYAL2 expression (P < or = 0.001) and modestly (P < or = 0.05) enhanced their migration. Therefore, the PTH (1-34) administration mode appears to distinctly modulate the migratory responses of the MG-63 moderately and Saos 2 well-differentiated osteosarcoma cell lines. Conclusively, the obtained data suggest that there is a regulatory effect of PTH (1-34), in an administration mode-dependent manner, on HA metabolism that is essential for osteosarcoma cell migration.
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C I Vardavas, M N Tzatzarakis, M Plada, A M Tsatsakis, A Papadaki, W H Saris, L A Moreno, A G Kafatos (2010)  Biomarker evaluation of Greek adolescents' exposure to secondhand smoke.   Hum Exp Toxicol 29: 6. 459-466 Jun  
Abstract: Exposure to secondhand smoke (SHS) is a significant threat to public health, and represents a danger for both the development and health status of children and adolescents. Taking the above into account, our aim was to quantify Greek adolescents' exposure to SHS using serum cotinine levels. During 2006, 341 adolescents aged 13-17 were randomly selected from high schools in Heraklion and agreed to participate as part of the European Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study. Blood samples were drawn from a random sample of 106 adolescents, while serum cotinine/nicotine concentrations were measured by Gas Chromatography-Mass Spectrometry (GC-MS). The mean levels of serum cotinine and nicotine were calculated at 1.60 +/- 2.18 ng/mL and 4.48 +/- 4.00 ng/mL, respectively, while 97.7% of the non-smoker adolescents were found to have measureable levels of serum cotinine indicating exposure to SHS. The analysis revealed that their paternal (p = .001) and maternal smoking habits (p = .018) as also the existence of a younger brother or sister (p = .008) were the main modifiers of SHS exposure during adolescence. Conclusively, almost all of the measured Greek adolescents were exposed to SHS, even when their parents were non-smokers. This finding indicates the need for both community and school-based educational programmes as also the implementation of a comprehensive ban on smoking in public places.
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Andreas D Flouris, Constantine I Vardavas, Giorgos S Metsios, Aristidis M Tsatsakis, Yiannis Koutedakis (2010)  Biological evidence for the acute health effects of secondhand smoke exposure.   Am J Physiol Lung Cell Mol Physiol 298: 1. L3-L12 Jan  
Abstract: A vast number of studies on the unfavorable effects of secondhand smoke (SHS) exist within the international literature, the majority of which evaluate longitudinal epidemiological data. Although limited, the experimental studies that assess the acute and short-term effects of exposure to SHS are also increasing in number. They include cellular, animal, and human studies that indicate a number of pathophysiological mechanisms through which the deleterious effects of SHS may arise. This current review evaluates the existing biological evidence regarding the acute health effects of SHS exposure. Analyses on the inhaled toxicants and the carcinogenicity of SHS are included as well as in-depth discussions on the evidence for acute SHS-induced respiratory, cardiovascular, metabolic, endocrine and immune effects, and SHS-induced influences on oxygen delivery and exercise. The influence of the length of exposure and the duration of the observed effects is also described. Moreover, recent findings regarding the underlying pathophysiological mechanisms related to SHS are depicted so as to generate models that describe the SHS-induced effects on different systems within the human body. Based on the presented biological evidence, it is concluded that brief, acute, transient exposures to SHS may cause significant adverse effects on several systems of the human body and represent a significant and acute health hazard. Future research directions in this area include research on the concentrations of tobacco smoke constituents in the alveolar milieu following SHS exposure, individual susceptibility to SHS, as well as the effects of SHS on neurobehavioral activity, brain cell development, synaptic development, and function.
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Maria Karabela, Constantine I Vardavas, Manolis Tzatzarakis, Aristeidis Tsatsakis, Douglas Dockery, Gregory N Connolly, Panagiotis Behrakis (2010)  The Relationship between Venue Indoor Air Quality and Urinary Cotinine Levels among Semiopen-Air Café Employees: What Factors Determine the Level of Exposure?   J Aerosol Med Pulm Drug Deliv Oct  
Abstract: Abstract Background: Exposure to second-hand smoke (SHS) is increasingly recognized as an occupational hazard to workers in the service industry. In areas of the world with moderate climates, open windows and doors are assumed to provide a work environment with only marginally increased exposures to SHS. Methods: We measured indoor fine particulate matter (PM2.5) in 50 semiopen air venues in Greece during the summer. Cotinine levels from a nonsmoking employee of each of these venues were measured from a postshift urine sample. Results: In these semiopen-air venues, the mean level of indoor PM 2.5 levels were 113.5 ± 72.3 μg/m(3). The mean postshift urinary cotinine levels of nonworking workers in these venues was 15 ng/mL. PM2.5 levels were strongly correlated with urinary cotinine concentrations (spearman's r = 0.914). Linear regression analyses indicated that when taking into account the time of the measurement, the day of the week, for each 1 cigarette/100 m(3) the indoor PM2.5 concentrations increased by 26.6 μg/m(3) [95% confidence interval (CI): 7.6-45.7 μg/m(3), p = 0.007) and urinary cotinine levels of nonsmoking workers increased by 5.0 ng/mL (95% CI: 0.4 to 9.6, p = 0.034). Conclusions: In a sample of bars and restaurants with windows and doors open, indoor PM2.5 concentrations were elevated and increased proportionately to the density of smoking. Cotinine levels of nonsmoking employees increased with indoor PM2.5 concentrations, and also with the density of smoking. Open windows and doors do not protect workers from exposure to second-hand smoke.
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A M Tsatsakis, M G Barbounis, M Kavalakis, M Kokkinakis, I Terzi, M N Tzatzarakis (2010)  Determination of dialkyl phosphates in human hair for the biomonitoring of exposure to organophosphate pesticides.   J Chromatogr B Analyt Technol Biomed Life Sci 878: 17-18. 1246-1252 May  
Abstract: A new, simple, fast and sensitive method that enables the measurement of four dialkyl phosphates (DAPs) in human head hair is presented in the current study. The dialkyl phosphates, dimethyl phosphate (DMP), diethyl phosphate (DEP), diethyl thiophosphate (DETP) and diethyl dithiophosphate (DEDTP) are non-selective metabolites of the organophosphate pesticides (OPs). The extraction of DAPs from hair matrix was achieved by one step methanolic extraction. Head hair samples from general population and population occupationally exposed to OPs were analysed using gas chromatography-mass spectrometry (GC-MS) after derivatization with pentafluorobenzylbromide. The recovery of the target compounds was estimated at 84.3% for DMP, 116.1% for DEP, 109.0% for DETP and 91.5% for DEDTP. The limit of quantitation (LOQ) and detection (LOD) was 20 and 6 pg/mg for DMP, 10 and 5 pg/mg for DEP and DETP and 5 and 3 pg/mg for DEDTP, respectively. With-run and between-run precision as well as accuracy was estimated. The percentage of positive hair samples for DMP, DEP, DETP and DEDTP for the group of general population was 63.0%, 96.3%, 66.7%, and 70.4% respectively. The samples from the group with occupational exposure were positive for all dialkyl phosphates analysed. The median concentrations for DMP were 165.0 and 181.7 pg/mg, for DEP were 51.2 and 812.9 pg/mg, for DETP were 54.0 and 660.1 pg/mg, and for DEDTP were 40.0 and 60.6 pg/mg for the general population group and the group with occupational exposure respectively. Significant differences in the levels of the total dialkyl phosphates amongst exposed and not exposed groups were observed (p<0.001). More specifically, the total ethyl phosphate (DEPs) and DAPs median concentrations were 119.5 and 301.5 pg/mg for the general population group and 1498.8 and 1694.4 pg/mg for the group with occupational exposure.
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Andrey N Kuskov, Anna A Voskresenskaya, Anastasiya V Goryachaya, Alexander A Artyukhov, Mikhail I Shtilman, Aristidis M Tsatsakis (2010)  Preparation and characterization of amphiphilic poly-N-vinylpyrrolidone nanoparticles containing indomethacin.   J Mater Sci Mater Med 21: 5. 1521-1530 May  
Abstract: Amphiphilic poly-N-vinylpyrrolidone derivatives (Amph-PVP) with different molecular weight of hydrophilic PVP fragment and one terminal hydrophobic n-alkyl fragment of different length were synthesized for preparation of nano-scaled particles in aqueous media. To estimate novel polymer efficiency and perspective as basis for drug delivery systems, the polymeric micelle-like particles were prepared by dialysis and solvent evaporation methods. Indomethacin was incorporated into hydrophobic inner core of these nanoparticles as a typical model drug. From the dynamic light-scattering measurements, the size of particles formed was less than 200 nm with narrow monodisperse size distribution and nanoparticles size slightly increased with the amount of indomethacin encapsulated into inner core of Amph-PVP particles. The critical aggregation concentration values for prepared polymer samples determined by fluorescence spectroscopy were in micromole range which is lower than it is for common low molecular weight surfactants. As the hydrophobic fragment of amphiphilic polymer increased, the critical aggregation concentration values decreased. An increase of polymer hydrophilic fragment molecular weight produced larger nanoaggregates. In vitro release experiments using indomethacin-loaded Amph-PVP nanoparticles exhibited the sustained release behavior without any burst effect for most polymer samples.
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A Tsakirakis, K M Kasiotis, N Arapaki, A Charistou, A Tsatsakis, C R Glass, K Machera (2010)  Determination of operator exposure levels to insecticide during bait applications in olive trees: Study of coverall performance and duration of application.   Int J Hyg Environ Health Sep  
Abstract: In this study the operator exposure levels during bait applications of an insecticide in olive groves were determined using a whole body dosimetry method for dermal exposure. The study design allowed the roles of application task duration and coverall type to be evaluated as factors influencing operator exposure. Twenty applications were carried out with knapsack sprayers in the Tanagra region of Viotia, Greece, ten of which were for a 1h and ten for a 3h duration. An in-house GC-NPD analytical method was developed and validated for the determination of malathion, the active substance (a.s.) of the insecticide formulation used in field trials. The mean recovery of field-fortified samples was 84% (%RSD=3.0). Field trial results generally indicated lower operator exposure levels than indicated by the most relevant operator exposure predictive model. Residues of malathion on internal dosimeters were compared to those measured on the respective outer coveralls (potential dermal exposure) to evaluate the protective factor of each one of the two coverall types used. Both coverall types provided satisfactory levels of protection and can be considered as suitable protection for the conditions of the application scenario studied. Furthermore, the results indicated that there is not a strong correlation between exposure levels and duration of application.
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Kostas Tsarouhas, Giannoula Soufla, Stavros Apostolakis, Apostolos Zaravinos, Matthew Panagiotou, Mazen Khoury, Joannis A Hassoulas, Aristides M Tsatsakis, Demetrios A Spandidos (2010)  Transcriptional regulation of TIMPs in ascending aorta aneurysms.   Thromb Res Sep  
Abstract: The events that result in the establishment and progression of aortic aneurysms are complex and multifactorial. However, degradation of the extracellular matrix (ECM) of aortic tunica media appears to be a consistent histopathological and biochemical feature. An increased local expression of matrix metalloproteinases (MMPs) as well as an imbalance between MMP expression and the expression of their natural tissue inhibitors (TIMPs) have been demonstrated in dilated aortic wall. We hypothesized that a distinct MMP and TIMP expression pattern underlies the development of ascending aorta dilation. To test our hypothesis, expression levels of 10 MMPs and 4 TIMPs were assessed by real-time PCR in dilated and normal aortic tissue derived from patients that underwent elective surgical repair of ascending aorta aneurysm (AAA) and coronary artery by-pass grafting, respectively. We found no statistically significant up- or down-regulation of any individual MMP. Surprisingly, the tissue inhibitor of metalloproteinases (TIMP)-3 was significantly more expressed in dilated aortic tissue compared to control tissue, thereby reflecting an effort to counteract MMP activity. Finally, when we evaluated the MMP and TIMP co-expression pattern in normal and dilated aortic tissue, we observed that in aortic aneurysms activation of the MMP system was characterised by the co-expression of more than one proteinase and the down-regulation of TIMP-1 and -2. The latter observation is the key regulatory point that leads to ECM degradation and, subsequently, to AAA formation.
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Constantine I Vardavas, Maria Plada, Manolis Tzatzarakis, Ascension Marcos, Julia Warnberg, Sonia Gomez-Martinez, Christina Breidenassel, Marcela Gonzalez-Gross, Aristeidis M Tsatsakis, Wim H Saris, Luis A Moreno, Anthony G Kafatos (2010)  Passive smoking alters circulating naïve/memory lymphocyte T-cell subpopulations in children.   Pediatr Allergy Immunol Jun  
Abstract: Vardavas CI, Plada M, Tzatzarakis M, Marcos A, Warnberg J, Gomez-Martinez S, Breidenassel C, Gonzalez-Gross M, Tsatsakis AM, Saris WH., Moreno LA, Kafatos AG. Passive smoking alters circulating naïve/memory lymphocyte T-cell subpopulations in children. Pediatr Allergy Immunol 2010. (c) 2010 John Wiley & Sons A/S While it has been indicated that exposure to second-hand smoke (SHS) can cause a local in vivo response, limited evidence exists on its possible systemic effects from population-based levels of exposure. We investigated into a possible systemic response in the immune parameters and lymphocyte subsets, i.e. B cell (CD19+), T cell (CD4+CD45RO+, CD4+CD45RA+, CD3+CD45RO+, CD3+CD45RA+) and natural killer (CD3+CD16CD56+) lymphocyte subsets relative to exposure to SHS. Blood was drawn from healthy, verified non-smoker, adolescent subjects (n = 68, mean age 14.2) and analysed for cotinine, antioxidants and lymphocyte immunophenotyping. SHS exposure was assessed using serum cotinine. Biomarker quantified exposure to SHS was correlated with a linear dose-response reduction in the percentages of memory CD4+CD45RO+ (p = 0.005) and CD3+CD45RO+ T-cell subsets (p = 0.005 and p = 0.003, respectively) and a linear increase in the percentage of naïve CD4+CD45RA+ and CD3+CD45RA+ T-cell subsets (p = 0.006 and p = 0.003, respectively). Additionally, higher exposure to SHS was associated with a higher CD4+CD45RA+ count (532 vs. 409 cells/ml, p = 0.017). Moreover, after controlling for age, gender, body mass index and plasma antioxidants, SHS exposure was found to be associated with the percentage of circulating naïve and memory CD4+ and CD3+ T-cell subpopulations, as revealed through a linear regression analysis. These findings indicate a systemic immunological response in healthy adolescents exposed to population-based levels of SHS exposure and imply an additional biological pathway for the interaction between exposure to SHS and its adverse effects on human health.
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Emmanouil K Symvoulakis, Constantine I Vardavas, Popi Fountouli, Aimilia Stavroulaki, Katerina M Antoniou, George Duijker, Manolis N Tzatzarakis, Katerina Sfiridaki, Eirini Bolonaki, Thanasis Alegakis, Aristidis M Tsatsakis (2010)  Time interval from cigarette smoke exposure to blood donation and markers of inflammation: should a smoking cut-off be designated?   Xenobiotica 40: 9. 613-620 Sep  
Abstract: Allogeneic blood transfusion leads to the infusion into the recipient of large amounts of antigens that may create conditions which are related to immune system modulation. The aim of this study was to determine the effects of smoking habit on vascular endothelial growth factor (VEGF) and interleukin 6 (IL-6) levels in the plasma of blood donors. Blood samples from 170 consecutive blood donors was collected and analyzed for serum markers, while questionnaire data was collected. Serum cotinine levels were calculated for non-smokers, while serum cytokine IL-6 and VEGF concentrations were also calculated among 88 randomly selected subjects. Controlling for the donors age and gender, a strong tendency was found for smoking within 24 h of the blood donation to be associated with a higher VEGF concentration of the donated blood (ß = 141.13, p = 0.06), while the donor age was independently related to VEGF levels (p = 0.001). Additionally the IL-6 levels in the transfused blood were independently associated with the donors age (p = 0.001) and gender (p = 0.002) but not with their smoking status. Further research is needed so as to assess the need of updating blood donation guide lines to regulate the time intervals between the time from the last cigarette and blood donation.
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A N Kuskov, A A Voskresenskaya, A V Goryachaya, M I Shtilman, D A Spandidos, A K Rizos, A M Tsatsakis (2010)  Amphiphilic poly-N-vinylpyrrolidone nanoparticles as carriers for non-steroidal anti-inflammatory drugs: characterization and in vitro controlled release of indomethacin.   Int J Mol Med 26: 1. 85-94 Jul  
Abstract: Novel amphiphilic poly-N-vinylpyrrolidone derivatives with different molecular weight of hydrophilic PVP fragment and one secondary di-n-alkyl terminal hydrophobic fragment of different length were synthesized to compare their inclination for formation of nano-scaled micelle-like aggregates in aqueous media with previously studied primary n-alkyl terminated poly-N-vinylpyrrolidones. The behavior of amphiphilies in water solutions was studied and critical aggregation concentration values for prepared polymer samples were determined by fluorescence spectroscopy and compared with those for primary n-alkyl derivatives. Polymeric micelle-like particles with or without encapsulated drug were prepared using dialysis or solvent evaporation techniques. Indomethacin was incorporated into hydrophobic inner core of these nanoparticles as a typical model drug. Dynamic light-scattering studies determined that the average size of particles formed was from 90 nm up to 600 nm with monodisperse size distribution and the nanoparticle size slightly increased with the amount of indomethacin encapsulated into inner core of the particles. In vitro release experiments carried out at different medium pH values using indomethacin-loaded nanoparticles exhibited slow and steady drug release into the medium.
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Maria Saroglou, Stavros Tryfon, Georgios Ismailos, Ioannis Liapakis, Manolis Tzatzarakis, Aristidis Tsatsakis, Apostolos Papalois, Demosthenes Bouros (2010)  Pharmacokinetics of Linezolid and Ertapenem in experimental parapneumonic pleural effusion.   J Inflamm (Lond) 7: 05  
Abstract: ABSTRACT: OBJECTIVE: To determine the extent of linezolid and ertapenem penetration into the empyemic fluid using a rabbit model of empyema. METHODS: An empyema was created via the intrapleural injection of Escherichia coli bacteria (ATCC 35218) into the pleural space of New Zealand white rabbits. After an empyema was verified by thoracocentesis, 24 hours post inoculation, linezolid (10 mg/kg) and ertapenem (60 mg/kg) were administered intravenously into 10 and 8 infected empyemic rabbits, respectively. Antibiotic levels were determined in samples of pleural fluid and blood serum, collected serially at 1, 2, 4, 6 and 8 hours, after administration each of the two antibiotics. RESULTS: Linezolid as well as ertapenem penetrate well into the empyemic pleural fluid, exhibiting a slower onset and decline compared to the corresponding blood serum levels. Equilibration between blood serum and pleural fluid compartments seems to occur at 1.5 hours for both linezolid and ertapenem, with peak pleural fluid levels (Cmaxpf of 2.02 +/- 0.73 <<mu>>g/ml and Cmaxpf of 3.74 +/- 1.39 <<mu>>g/ml, correspondingly) occurring 2 hours post antibiotics administration and decreasing very slowly thereafter. The serum concentrations for both antibiotics were significantly lower from the corresponding pleural fluid ones during the 8 hours collecting data, with the exception of samples collected at the 1st hour (Cmaxserum of 2.1 +/- 1.2 <<mu>>g/ml for linezolid and Cmaxserum of 6.26 +/- 2.98 <<mu>>g/ml for ertapenem). CONCLUSION: Pleural fluid levels of both antibiotics are inhibitory for common specified pathogens causing empyema.
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2009
A M Tsatsakis, M N Tzatzarakis, D Koutroulakis, M Toutoudaki, S Sifakis (2009)  Dialkyl phosphates in meconium as a biomarker of prenatal exposure to organophosphate pesticides: a study on pregnant women of rural areas in Crete, Greece.   Xenobiotica 39: 5. 364-373 May  
Abstract: The authors developed a sensitive analytical method for the determination of dialkyl phosphates (DAPs) in meconium. This method was applied to determine the DAPs, which are non-specific metabolites of the organophosphate pesticides (OPs), in meconium of newborns by mothers who live in rural areas in Crete, Greece. DAPs are considered as biomarkers of exposure to OPs. Meconium is produced in the foetus at approximately 16 weeks of gestation and it acts as a repository of many xenobiotics. The determined organophosphate metabolites were dimethylphosphate (DMP), diethylphosphate (DEP), dimethylthiophosphate (DMTP), diethylthiophosphate (DETP), and diethyldithiophosphate (DEDTP). The DAPs were extracted from meconium by liquid-solid extraction, derivatized, and analysed by gas chromatography-mass spectrometry (GC-MS). The mean percentile recoveries were 76.9%, 65.2%, 94.1%, 109.4%, and 107.2% for DMP, DEP, DMTP, DETP, and DEDTP, respectively. The percentage of positive samples was 92.1% for DMP, 36.8% for DEP, 60.5% for DMTP, 63.2% for DETP, and 57.9% for DEDTP. Mean (+/- standard deviation) and the range concentrations of the positive samples (ng g(-1)) were 126.74 +/- 142.73 (10.64-739.45), 11.46 +/- 20.43 (1.50-79.14), 215.05 +/- 187.34 (8.54-662.16), 4.92 +/- 5.09 (1.25-19.04), and 1.84 +/- 2.07 (0.5-8.04) for DMP, DEP, DMTP, DETP, and DEDTP, respectively. Statistical analysis revealed no significant difference in meconium levels between high- and low-risk groups of exposure of pregnant women. However, the results of this study demonstrate that DAPs in meconium may be considered as a potential biomarker for the assessment of foetal exposure to organophosphate pesticides.
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Konstantin Krasagakis, Sabine Kruger-Krasagakis, Jürgen Eberle, Aristidis Tsatsakis, Androniki D Tosca, Efstathios N Stathopoulos (2009)  Co-expression of KIT receptor and its ligand stem cell factor in Merkel cell carcinoma.   Dermatology 218: 1. 37-43 11  
Abstract: BACKGROUND/AIMS: KIT receptor has been implicated in the pathogenesis of cancer, either by mutation or autocrine activation. Merkel cell carcinoma (MCC) is a rare KIT-positive cutaneous tumor. We investigated the co-expression of KIT and its ligand stem cell factor (SCF) in MCC. METHODS: Sixteen specimens from 13 MCC patients of various tumor stages were examined by immunohistochemistry for SCF, KIT, Ki67/MIB-1 and cleaved caspase 3 expression, and for apoptosis by TUNEL. RESULTS: KIT was expressed in 13 of 16 tumors, and SCF in 15 of 16 specimens. Co-expression of KIT and SCF was detected in 12 of 16 tumors. KIT and SCF immunoreactivity scores were independent of tumor stage. Ki67/MIB-1 proliferation rates were high, whereas apoptosis rates were low, and did not depend on KIT or SCF expression. CONCLUSION: Co-expression of KIT and SCF in a high percentage of MCC tumors hints to an autocrine mechanism. KIT and SCF expression in primary tumors and in metastases suggests an early event in Merkel cell transformation.
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Maria G Margariti, Aristidis M Tsatsakis (2009)  Analysis of dialkyl phosphate metabolites in hair using gas chromatography-mass spectrometry: a biomarker of chronic exposure to organophosphate pesticides.   Biomarkers 14: 3. 137-147 May  
Abstract: The aim of our study was to develop and validate an analytical approach for the quantitative determination of three dialkyl phosphate (DAP) metabolites, dimethyl phosphate (DMP), dimethyl thiophosphate (DMTP) and diethyl phosphate (DEP), of organophosphate pesticides (OPs) in hair samples. The proposed methodology comprises a decontamination step, solid-liquid extraction, followed by liquid-liquid extraction, pentafluorobenzyl bromide derivatization, clean-up on Florisil/PSA column and analysis by gas chromatography-mass spectrometry (GC-MS). Extraction recovery, obtained from 50 mg hair samples spiked at two concentration levels, ranged from 56.1 to 107.9% and the within-day precision ranged from 13.5 to 17.5%. Limits of detection (LODs) ranged from 0.02 to 0.10 ng mg(-1). The results obtained from the analysis of hair samples of 30 agricultural workers show the suitability of the proposed method for monitoring people occupationally exposed to OPs. The most frequently detected compound was DEP followed by DMP. This is the first report on the detection of dialkyl phosphates in human hair which reflects the ability of hair testing to assess chronic exposure to OPs.
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A M Tsatsakis, A Zafiropoulos, M N Tzatzarakis, G N Tzanakakis, A Kafatos (2009)  Relation of PON1 and CYP1A1 genetic polymorphisms to clinical findings in a cross-sectional study of a Greek rural population professionally exposed to pesticides.   Toxicol Lett 186: 1. 66-72 Apr  
Abstract: Allelic variants of CYP1A1 and PON1 have been extensively studied as susceptibility factors in toxic response, although little is known about the role of these variants as risk factors for the plethora of diseases appearing in the human population. In this study we investigated the hypothesis of correlation of CYP1A1 and PON1 enzymes with the incidence of various medical examination findings in a Greek rural population professionally exposed to a variety of pesticides. The medical history of 492 individuals, randomly selected for the total population of 42,000, was acquired by interviews and their genotype determined for the CYP1A1*2A, PON1 M/L and PON1 Q/R polymorphisms. The assessment of exposure to pesticides of the population was verified by analytical methods. Analysis of the genetic data revealed that the allele frequencies of PON1 R, M and CYP1A1*2A alleles were 0.243, 0.39 and 0.107 respectively. The CYP1A1*2A polymorphism was found to have significant association with chronic obstructive pneumonopathy (p=0.045), peripheral circulatory problems (trend p=0.042), arteritis (p=0.022), allergies (trend p=0.046), hemorrhoids (trend p=0.026), allergic dermatitis (p=0.0016) and miscarriages (p=0.012). The PON1 Q/R polymorphism was found to have significant association with hypertension (p=0.046) and chronic constipation (p=0.028) whereas, the L/M polymorphism, with diabetes (p=0.036), arteritis (trend p=0.022) and hemorrhoids (trend p=0.027). Our results demonstrated an association between the CYP1A1/PON1 polymorphisms and several medical examination findings, thus indicating the possible involvement of the human detoxification system to health effects in a rural population exposed professionally to pesticides.
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Andreas D Flouris, Giorgos S Metsios, Andres E Carrillo, Athanasios Z Jamurtas, Konstantinos Gourgoulianis, Theodoros Kiropoulos, Manolis N Tzatzarakis, Aristidis M Tsatsakis, Yiannis Koutedakis (2009)  Acute and short-term effects of secondhand smoke on lung function and cytokine production.   Am J Respir Crit Care Med 179: 11. 1029-1033 Jun  
Abstract: RATIONALE: The acute effect of secondhand smoke (SHS) on lung function and the duration of system disruption remain unknown. OBJECTIVES: To assess the SHS effects and their duration on lung function and inflammatory markers. METHODS: In a randomized single-blind crossover experiment data were obtained from 16 (8 women) nonsmoking adults at baseline and at 0, 1, and 3 hours after a 1-hour SHS exposure set at bar/restaurant SHS levels. MEASUREMENTS AND MAIN RESULTS: Serum and urine cotinine, lung function, and cytokines IL-4, IL-5, IL-6, tumor necrosis factor (TNF)-alpha, and IFN-gamma. At 0 hours most lung function parameters were significantly reduced (indicative: FEV(1), 4.3 +/- 0.4 vs. 3.8 +/- 0.3 L; FEV(1)/FVC, 0.9 +/- 0.1 vs. 0.8 +/- 0.1; P < 0.05) but at 3 hours they were at baseline levels. In contrast, cotinine (serum, 8.9 +/- 3.2 vs. 35.5 +/- 10.2 ng x ml(-1)), IL-4 (41.3 +/- 5.8 vs. 44.2 +/- 4.5 pg x ml(-1)), IL-5 (36.1 +/- 3.2 vs. 60.1 +/- 7.0 pg x ml(-1)), IL-6 (2.5 +/- 0.3 vs. 7.6 +/- 1.4 pg x ml(-1)) and IFN-gamma (0.3 +/- 0.2 vs. 0.6 +/- 0.2 IU x ml(-1)) at 3 hours were higher than at baseline (P < 0.05). IL-4 and TNF-alpha increased only in men, whereas IL-5, IL-6, and IFN-gamma were different between sexes after exposure (P < 0.05). Regression analyses revealed inverse associations of FEV(1) and FEV(1)/FVC ratio with IL-5 (P < 0.05) in men and with IL-5 (P = 0.01), IL-6 (P < 0.001), IFN-gamma (P = 0.034) and serum cotinine (P < 0.001) in women. CONCLUSIONS: We conclude that 1 hour of SHS exposure at bar/restaurant levels is accompanied by significant decrements on lung function and marked increases in inflammatory cytokines, particularly in men. More importantly, whereas most smoke-induced effects on lung function appear to recede within 60 minutes, inflammatory cytokines remain elevated for at least 3 hours after exposure to SHS.
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Vasilis P Androutsopoulos, Ketan Ruparelia, Randolph R J Arroo, Aristidis M Tsatsakis, Demetrios A Spandidos (2009)  CYP1-mediated antiproliferative activity of dietary flavonoids in MDA-MB-468 breast cancer cells.   Toxicology 264: 3. 162-170 Oct  
Abstract: Among the different mechanisms proposed to explain the cancer-protecting effect of dietary flavonoids, substrate-like interactions with cytochrome P450 CYP1 enzymes have recently been explored. In the present study, the metabolism of the flavonoids chrysin, baicalein, scutellarein, sinensetin and genkwanin by recombinant CYP1A1, CYP1B1 and CYP1A2 enzymes, as well as their antiproliferative activity in MDA-MB-468 human breast adenocarcinoma and MCF-10A normal breast cell lines, were investigated. Baicalein and 6-hydroxyluteolin were the only conversion products of chrysin and scutellarein metabolism by CYP1 family enzymes, respectively, while baicalein itself was not metabolized further. Sinensetin and genkwanin produced a greater number of metabolites and were shown to inhibit strongly in vitro proliferation of MDA-MB-468 cells at submicromolar and micromolar concentrations, respectively, without essentially affecting the viability of MCF-10A cells. Cotreatment of the CYP1 family inhibitor acacetin reversed the antiproliferative activity noticed for the two flavones in MDA-MB-468 cells to 13 and 14 microM respectively. In contrast chrysin, baicalein and scutellarein inhibited proliferation of MDA-MB-468 cells to a lesser extent than sinensetin and genkwanin. The metabolism of genkwanin to apigenin and of chrysin to baicalein was favored by CYP1B1 and CYP1A1, respectively. Taken together the data suggests that CYP1 family enzymes enhance the antiproliferative activity of dietary flavonoids in breast cancer cells, through bioconversion to more active products.
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Maria G Margariti, Aristidis M Tsatsakis (2009)  Assessment of long-term subacute exposure to dimethoate by hair analysis of dialkyl phosphates DMP and DMTP in exposed rabbits: The effects of dose, dose duration and hair colour.   Environ Res 109: 7. 821-829 Oct  
Abstract: Hair analysis for dialkyl phosphates' (DAPs) residues could provide a measure of chronic exposure to organophosphate pesticides (OPs). The aim of this study was to determine whether these metabolites can be internally incorporated into the hair of rabbits exposed to dimethoate and also to investigate the influence of dose and dose duration of this OP, as well as the effect of hair colour on the concentrations of its DAPs in hair. Two-coloured rabbits were daily exposed to dimethoate (0, 12 or 24mgkg(-1) body weight) via their drinking water. Hair samples of both colours were obtained 4 and 6 months after the beginning of exposure from the back of all treated rabbits, and each hair colour sample was analyzed for dimethyl phosphate (DMP) and dimethyl thiophosphate (DMTP) by gas chromatography-mass spectrometry (GC-MS). Analysis revealed the incorporation of these metabolites into the rabbit hair in a dose-dependent manner. The mean concentrations found ranged from 0.18 to 0.77ngmg(-1) for DMP and from 0.43 to 1.53ngmg(-1) for DMTP. Mixed results for the significance of the relationship between dose duration and the levels of the two DAPs in hair are observed. Hair pigmentation does not appear to affect the concentration values of DMTP, whereas it seems to be a critical factor in the incorporation of DMP into hair. These data confirm the ability of hair testing to assess chronic OP exposure by the detection of DAPs.
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George D Kymionis, Vasilios F Diakonis, Sophia I Panagopoulou, Michael A Grentzelos, Dimitris C Kazakos, Manolis N Tzatzarakis, Aristidis M Tsatsakis, Aristophanis I Pallikaris (2009)  Mitomycin C aqueous humor concentration after photorefractive keratectomy: an experimental study.   Eur J Ophthalmol 19: 5. 738-742 Sep/Oct  
Abstract: PURPOSE: To evaluate mitomycin C (MMC) aqueous humor concentration after photorefractive keratectomy (PRK). METHODS: In this experimental study, twenty-four eyes of 12 male pigmented rabbits were divided into 4 groups and studied at the Institute of Vision and Optics, Department of Medicine, University of Crete, Greece. Eyes in groups 1 and 2 underwent PRK to correct -5 diopters (D) in a 6-mm optical zone, while sponges soaked with 0.02% MMC were applied on the exposed corneal stroma for 60 and 120 seconds, respectively. Similarly, eyes in groups 3 and 4 underwent PRK to correct -10 D in a 6-mm optical zone, while sponges soaked with 0.02% MMC were applied on the exposed corneal stroma for 60 and 120 seconds, respectively. Aqueous humor was extracted from all rabbit eyes 10 minutes after MMC application and high-performance liquid chromatography was performed immediately to detect and quantify MMC levels. RESULTS: The mean aqueous humor concentration of MMC was 0.23+/-0.03 microg/mL, 0.39+/-0.05 microg/mL, 0.28+/-0.04 microg/mL, and 0.52+/-0.16 microg/mL in groups 1, 2, 3, and 4, respectively. The effect of application time and correction on aqueous humor MMC concentration was significant (p<0.0001 and p=0.019), while the exposure time had a greater impact on aqueous humor MMC concentration when compared with the attempted correction. CONCLUSIONS: Both exposure time of MMC on the corneal stroma and the attempted correction was correlated with MMC aqueous humor concentrations.
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Aikaterini Berdiaki, Dragana Nikitovic, Aristeidis Tsatsakis, Pavlos Katonis, Nikos K Karamanos, George N Tzanakakis (2009)  bFGF induces changes in hyaluronan synthase and hyaluronidase isoform expression and modulates the migration capacity of fibrosarcoma cells.   Biochim Biophys Acta 1790: 10. 1258-1265 Oct  
Abstract: BACKGROUND: Hyaluronan (HA) a glycosaminoglycan, is capable of transmitting extracellular matrix derived signals to regulate cellular functions. In this study, we investigated whether the changes in HT1080 and B6FS fibrosarcoma cell lines HA metabolism induced by basic fibroblast growth factor (bFGF) are correlated to their migration. METHODS: Real-time PCR, in vitro wound healing assay, siRNA transfection, enzyme digestions, western blotting and immunofluorescence were utilized. RESULTS: bFGF inhibited the degradation of HA by decreasing hyaluronidase-2 expression in HT1080 cells (p=0.0028), increased HA-synthase-1 and -2 expression as we previously found and enhanced high molecular weight HA deposition in the pericellular matrix. Increased endogenous HA production (p=0.0022) and treatment with exogenous high molecular weight HA (p=0.0268) correlated with a significant decrease of HT1080 cell migration capacity. Transfection with siHAS2 and siHAS1 showed that mainly HAS1 synthesized high molecular weight HA regulates HT1080 cell motility. Induced degradation of the HA content by hyaluronidase treatment and addition of low molecular weight HA, resulted in a significant stimulation of HT1080 cells' motility (p<0.01). In contrast, no effects on B6FS fibrosarcoma cell motility were observed. CONCLUSIONS: bFGF regulates, in a cell-specific manner the migration capability of fibrosarcoma cells by modulating their HA metabolism. HA metabolism is suggested to be a potential therapeutic target in fibrosarcoma.
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Ioannis Stiakakis, Stamatis D Belivanis, Manolis N Tzatzarakis, Manolis Fragoulis, Aristidis M Tsatsakis (2009)  Disputed case of homicide by smothering due to severe amitriptyline intoxication of the victim.   J Forensic Leg Med 16: 5. 280-283 Jul  
Abstract: We report a fatal case of a female for whom the forensic autopsy revealed injuries to the external respiratory orifices indicating smothering. Subsequent postmortem toxicological analysis confirmed heavy amitriptyline acute intoxication. The victim had serious psychological problems, was under long-term treatment with antidepressants and was a systematic alcohol abuser. Forensic autopsy determined damage to the external airways, along with multiple formal petechial hemorrhages (Tardieu) in various parts of the body. The presence of amitriptyline, nortriptyline and 10-hydroxynortriptyline was confirmed by GC-MS and quantified by HPLC in blood (7.0 microg/ml amitriptyline and 7.4 microg/ml nortriptyline). The cause of death was disputed between severe intoxication (poisoning or suicide attempt) and smothering due to controversial evidence.
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Vasilis P Androutsopoulos, Aristidis M Tsatsakis, Demetrios A Spandidos (2009)  Cytochrome P450 CYP1A1: wider roles in cancer progression and prevention.   BMC Cancer 9: 06  
Abstract: CYP1A1 is one of the main cytochrome P450 enzymes, examined extensively for its capacity to activate compounds with carcinogenic properties. Continuous exposure to inhalation chemicals and environmental carcinogens is thought to increase the level of CYP1A1 expression in extrahepatic tissues, through the aryl hydrocarbon receptor (AhR). Although the latter has long been recognized as a ligand-induced transcription factor, which is responsible for the xenobiotic activating pathway of several phase I and phase II metabolizing enzymes, recent evidence suggests that the AhR is involved in various cell signaling pathways critical to cell cycle regulation and normal homeostasis. Disregulation of these pathways is implicated in tumor progression. In addition, it is becoming increasingly evident that CYP1A1 plays an important role in the detoxication of environmental carcinogens, as well as in the metabolic activation of dietary compounds with cancer preventative activity. Ultimately the contribution of CYP1A1 to cancer progression or prevention may depend on the balance of procarcinogen activation/detoxication and dietary natural product extrahepatic metabolism.
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2008
A M Tsatsakis, M N Tzatzarakis, M Tutudaki (2008)  Pesticide levels in head hair samples of Cretan population as an indicator of present and past exposure.   Forensic Sci Int 176: 1. 67-71 Mar  
Abstract: In the present work we assessed chronic exposure of different working population groups of Messara and Sitia districts, Crete, Greece, to common currently used pesticides (diazinon, fenthion, methyl parathion and malathion) and two banned pesticides hexachlorocyclohexane (HCH) and DDT. The study population (211 persons, 110 females and 101 males) was divided to three groups; people working in greenhouses, animal breeders and people working in open cultivations. Methanolic extraction of pulverized hair was used for organophosphate pesticides extraction, followed by liquid-liquid extraction with water-ethyl acetate as a clean up step. The extraction of organochlorine pollutants was performed by acidic hydrolysis of the hair matrix followed by liquid-liquid and solid phase extraction. The levels of the aforementioned pesticides were measured by GC-ECD and gas chromatography-mass spectrometry (GC-MS). The median concentrations of a-HCH, HCB, lindane, opDDE, ppDDE, opDDD, ppDDD + opDDT and ppDDT were determined at 7.2, 2.2, 70.2, 2.7, 5.7, 3.1, 2.6 and 23.2 pg/mg. The median concentration of total HCHs and DDTs detected in the three working groups were: 95.0 and 8.9 pg/mg for the greenhouse workers, 38.2 and 3.3 pg/mg for the animal breeders and 24.1 and 5.2 pg/mg for the open cultivation group. Ten head hair samples were positive for diazinon at a mean concentration of 2.8 pg/mg. Fenthion, methyl parathion and malathion were not detected. Our results demonstrated the ability to assess chronic human past pesticides exposure, offering valuable information to epidemiological clinical studies.
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A Berdiaki, A Zafiropoulos, E Fthenou, P Katonis, A Tsatsakis, N K Karamanos, G N Tzanakakis (2008)  Regulation of hyaluronan and versican deposition by growth factors in fibrosarcoma cell lines.   Biochim Biophys Acta 1780: 2. 194-202 Feb  
Abstract: Versican, a large chondroitin sulphate proteoglycan and hyaluronan (HA), a non-sulphated glycosaminoglycan are major constituents of the pericellular matrix. In many neoplastic tissues, changes in the expression of versican and HA affect tumour progression. Here, we analyse the synthesis of versican and hyaluronan by fibrosarcoma cells, and document how the latter is affected by PDGF-BB, bFGF and TGFB2, growth factors endogenously produced by these cells. Fibrosarcoma cell lines B6FS and HT1080 were utilised and compared with normal lung fibroblasts (DLF). The major versican isoforms expressed by DLF and B6FS cells were V0 and V1. Treatment of B6FS cells with TGFB2 showed a significant increase of V0 and V1 mRNAs. Versican expression in HT1080 cells was not significantly affected by any of the growth factors. In addition, TGFB2 treatment increased versican protein in DLF cells. HA, showed approximately a 2-fold and a 9-fold higher production in DLF cells compared to B6FS and HT1080 cells, respectively. In HT1080 cells, HA biosynthesis was significantly increased by bFGF, whereas, in B6FS cells it was increased by TGFB2 and PDGF-BB. Furthermore, analysis of HA synthases (HAS) expression indicated that HT1080 expressed similar levels of all three HAS isoforms in the following order: HAS2> HAS3> HAS1. bFGF shifted that balance by increasing the abundance of HAS1. The major HAS isoform expressed by B6FS cells was HAS2. PDGF-BB and TGFB2 showed the most prominent effects by increasing both HAS2 and HAS1 isoforms. In conclusion, these growth factors modulated, through upregulation of specific HAS isoforms, HA synthesis, secretion and net deposition to the pericellular matrix.
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E Fthenou, A Zafiropoulos, P Katonis, A Tsatsakis, N K Karamanos, G N Tzanakakis (2008)  Chondroitin sulfate prevents platelet derived growth factor-mediated phosphorylation of PDGF-Rbeta in normal human fibroblasts severely impairing mitogenic responses.   J Cell Biochem 103: 6. 1866-1876 Apr  
Abstract: Platelet-derived growth factor (PDGF) is a major polypeptide mitogen for cells of mesenchymal origin such as fibroblasts. Chondroitin sulfate chains (CS), which are abundant in the extracellular matrix have been shown to physically interact with PDGF-BB modulating its biological function. The aim of the present study was to examine the involvement of CS on PDGF-BB induced proliferative responses and receptor activation in human lung fibroblasts. The addition of exogenous free CS chains caused a significant downregulation of the PDGF-BB mediated mitogenic and chemotactic responses. Similar results were obtained by the increase of endogenous CS biosynthesis after beta-D-xyloside treatment. Furthermore, removal of the membrane-bound CS chains by selective enzymatic treatment significantly increased the proliferative capacity of human fibroblasts. Analysis of PDGF-R phosphorylation in the presence of CS or beta-D-xyloside, revealed a reduction of PDGF-Rbeta phosphorylation in the tyrosine residue 1021. These results demonstrate, for the first time, that CS either soluble or surface bound downregulates the mitogenic responses of PDGF-BB in normal human lung fibroblasts through the reduction of PDGF-Rbeta phosphorylation.
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Dragana Nikitovic, Aikaterini Berdiaki, Alexandros Zafiropoulos, Pavlos Katonis, Aristidis Tsatsakis, Nikos K Karamanos, George N Tzanakakis (2008)  Lumican expression is positively correlated with the differentiation and negatively with the growth of human osteosarcoma cells.   FEBS J 275: 2. 350-361 Jan  
Abstract: Osteosarcoma is the most common primary bone tumour associated with childhood and adolescence. The possible role of the small leucine-rich proteoglycan, lumican, in the growth and metastasis of various cancer types has recently been investigated. In this study, the expression of lumican was examined in moderately differentiated (MG-63) and well-differentiated (Saos 2) human osteosarcoma cell lines of high and low metastatic capability, respectively. Real-time PCR, western blotting with antibodies against the protein core and keratan sulfate, and specific enzymatic digestions were the methods employed. The two human osteosarcoma cell lines were found to express and secrete lumican partly substituted with keratan sulfate glycosaminoglycans. Importantly, the non-metastatic, well-differentiated Saos 2 cells produced lumican at rates that were up to sevenfold higher than those of highly metastatic MG-63 cells. The utilization of short interfering RNA specific for the lumican gene resulted in efficient down-regulation of its mRNA levels in both cell lines. The growth of Saos 2 cells was inhibited by lumican, whereas their migration and chemotactic response to fibronectin were found to be promoted. Lumican expression was negatively correlated with the basal level of Smad 2 activation in these cells, suggesting that lumican may affect the bioavailability of Smad 2 activators. By contrast, these cellular functions of highly aggressive MG-63 cells were demonstrated not to be sensitive to a decrease in their low endogenous lumican levels. These results suggest that lumican expression may be positively correlated with the differentiation and negatively correlated with the progression of osteosarcoma.
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Dragana Nikitovic, Paulos Katonis, Aristidis Tsatsakis, Nikos K Karamanos, George N Tzanakakis (2008)  Lumican, a small leucine-rich proteoglycan.   IUBMB Life 60: 12. 818-823 Dec  
Abstract: Lumican belongs to the family of small leucine-rich repeat proteoglycans. Recent studies have shown that lumican participates in the maintenance of tissue homeostasis and modulates cellular functions including cell proliferation, migration, and differentiation. The expression of lumican has been correlated to the growth and metastasis of various malignancies; however, its exact role in tumorogenesis remains elusive. This review focuses upon the role of lumican in cell biology, providing insights into molecular mechanisms that lumican likely utilizes to control processes relevant to tumorogenesis.
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A M Tsatsakis, M N Tzatzarakis, M Tutudaki, F Babatsikou, A K Alegakis, C Koutis (2008)  Assessment of levels of organochlorine pesticides and their metabolites in the hair of a Greek rural human population.   Hum Exp Toxicol 27: 12. 933-940 Dec  
Abstract: We present the assessment of chronic exposure of the rural population of Helia Peloponnesus, Greece to banned organochlorine pesticides, hexachlorocyclohexane (HCH), and 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT), using hair analysis. A total of 222 head hair samples were collected and analyzed for the presence of those organochlorine pesticides and their metabolites or isomers. Gas chromatography coupled to mass spectrometry was used to measure the levels of the pollutants. The median concentrations of alpha-HCH, hexachlorobenzene, lindane, ortho para 1,1-dichloro-2,2-bis-(4-chlorophenyl)ethylene (opDDE), para para 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (ppDDE), ortho para 1,1-dichloro-2,2-bis(4-chlorophenyl)ethane (opDDD), para para 1,1-dichloro-2,2-bis(4-chlorophenyl)ethane (ppDDD) + ortho para 1,1,1-trichloro-2,2-bis(4-chlorophenyl)-ethane, and para para 1,1,1-trichloro-2,2-bis(4-chlorophenyl)-ethane were determined at 40.4, 19.7, 124.2, 6.2, 7.8, 73.1, 8.0, and 5.7 pg/mg. The median concentration of total HCHs and DDTs were 117.8 pg/mg and 9.4 pg/mg, respectively. The levels of total HCHs were much higher than the levels of DDTs in the hair samples of the studied population. This may be attributed to the presence of lindane, a pesticide officially banned in 2002. It is interesting to see that DDTs are still traced in samples despite their use being banned for more than three decades. There was no difference in the levels of the detected pesticides in hair sampled from men or women. The concentration of HCHs remains high and relatively stable across the age groups, suggesting constant exposure until very recently. The concentration of the total DDTs and the parent compound, pp-DDT presents a statistically significant decreasing trend across the age groups.
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Alexandros Zafiropoulos, Dragana Nikitovic, Pavlos Katonis, Aristidis Tsatsakis, Nikos K Karamanos, George N Tzanakakis (2008)  Decorin-induced growth inhibition is overcome through protracted expression and activation of epidermal growth factor receptors in osteosarcoma cells.   Mol Cancer Res 6: 5. 785-794 May  
Abstract: Decorin is an established natural oncosuppressive factor whose action is being studied in detail. Recently, decorin gene therapy formulations using adenoviral vectors have been shown in several animal models with very promising results. The present study describes the first exception to the established oncosuppression model using human osteosarcoma cells. MG-63 osteosarcoma cells were found to constitutively produce decorin, and furthermore, to be resistant to decorin-induced growth arrest. On the contrary, decorin seemed to be beneficial to osteosarcoma cells because it was necessary for MG-63 cell migration and acted as a mediator, counteracting the transforming growth factor-beta2-induced cytostatic function. Efforts to determine how MG-63 cells could overcome the decorin-induced cytostatic effect established that decorin in MG-63 cells does not induce p21 expression nor does it cause protracted retraction and inactivation of the epidermal growth factor receptor. Conversely, epidermal growth factor receptor seemed to be overexpressed and continuously phosphorylated. In view of the proposed design of decorin-based anticancer therapeutic strategies, our study provides new data on pathways that cancer cells might employ to overcome the established decorin-induced growth suppression.
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Georgia Chatzinikolaou, Dragana Nikitovic, Athanasia Asimakopoulou, Aristidis Tsatsakis, Nikos K Karamanos, George N Tzanakakis (2008)  Heparin--a unique stimulator of human colon cancer cells' growth.   IUBMB Life 60: 5. 333-340 May  
Abstract: The cancer microenvironment and the interactions between cancer and surrounding tissue cells are thought to play a pivotal role in tumor development and progression. Glycosaminoglycans (GAGs)/proteoglycans (PGs) are major constituents of the extracellular matrix, the composition of which may affect various cellular functions. In the present study, the effects of GAGs on the proliferation of HT29, SW1116, and HCT116 human colon cancer cell lines were examined using exogenously added GAGs, an inhibitor of endogenous GAG sulfation and specific glycosidase digestions. Our results demonstrate that colon cancer cell growth was exclusively stimulated by exogenously added heparin and insensitive to endogenous GAGs/PGs production, in a sulfation pattern-related manner. Treatment of the tested cell lines with the FGF-2 neutralizing antibody showed that the stimulatory effect of heparin on the cells' growth was not FGF-2-dependent. Responsiveness of colon cancer cell lines to exogenous heparin/heparan sulfate may play a role in their growth and metastasis.
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2007
Giorgos S Metsios, Andreas D Flouris, Athanasios Z Jamurtas, Andres E Carrillo, Demetrios Kouretas, Anastasios E Germenis, Konstantinos Gourgoulianis, Theodoros Kiropoulos, Manolis N Tzatzarakis, Aristeidis M Tsatsakis, Yiannis Koutedakis (2007)  A brief exposure to moderate passive smoke increases metabolism and thyroid hormone secretion.   J Clin Endocrinol Metab 92: 1. 208-211 Jan  
Abstract: CONTEXT: Active smoking influences normal metabolic status and thyroid function. OBJECTIVE: The objective was to assess experimentally the effects of 1 h of moderate passive smoking in a controlled simulated bar/restaurant environment on the metabolism and thyroid hormone levels in healthy nonsmokers. PARTICIPANTS: Eighteen (nine females, nine males) healthy individuals (mean +/- sd: age, 25.3 +/- 3.1 yr; height, 174.0 +/- 10.1 cm; weight, 65.2 +/- 13.7 kg) participated in the study. DESIGN: In repeated-measures randomized blocks, participants visited the laboratory on 2 consecutive days. In the experimental condition, they were exposed to 1 h of moderate passive smoking at a carbon monoxide concentration of 23 +/- 1 ppm in an environmental chamber, whereas in the control condition participants remained in the same chamber for 1 h breathing normal atmospheric air. MAIN OUTCOME MEASURES: In both conditions, cotinine serum and urine levels, resting energy expenditure (REE), as well as concentration of T3, free T4, and TSH were assessed before participants entered the chamber and immediately after their exit. Heart rate and blood pressure were tested in 10-min intervals during all REE assessments. RESULTS: The mean +/- sd difference of serum and urine cotinine levels (-0.27 +/- 3.94 vs. 14.01 +/- 6.54 and 0.05 +/- 2.07 vs. 7.23 +/- 3.75, respectively), REE (6.73 +/- 98.06 vs. 80.58 +/- 120.91) as well as T3 and free T4 (0.05 +/- 0.11 vs. 0.13 +/- 0.12 and 0.02 +/- 0.15 vs. 0.22 +/- 0.20) were increased in the experimental compared with the control condition at baseline and follow-up (P < 0.05). No statistically significant variation was observed in the mean difference of the remaining parameters (P > 0.05). Serum and urine cotinine values were linearly associated with REE (P < 0.05). CONCLUSION: One hour of passive smoking at bar/restaurant levels is accompanied by significant increases in metabolism and thyroid hormone levels.
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Maria G Margariti, Andreas K Tsakalof, Aristidis M Tsatsakis (2007)  Analytical methods of biological monitoring for exposure to pesticides: recent update.   Ther Drug Monit 29: 2. 150-163 Apr  
Abstract: Extensive use of synthetic pesticides for agricultural and nonagricultural purposes began in the past 50 years. As a result of their wide and extensive application, exposure to hazardous pesticides is a concern to the general population and occupationally exposed persons. Robust methods are therefore needed for measuring markers of pesticide exposure. This article presents a review of the most recently published analytical methodologies and instrumentations developed for and applied to biological monitoring of exposure to pesticides of various classes. Most of the methods reviewed here are based on chromatography combined with mass spectrometry detection. This work clearly demonstrates that although gas chromatography still appears to be the most widely employed technique for pesticide analysis in various biological samples, recently a trend has been observed toward the use of liquid chromatography coupled with tandem mass spectrometry.
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2006
Ekatherina Charvalos, Manolis N Tzatzarakis, Françoise Van Bambeke, Paul M Tulkens, Aristidis M Tsatsakis, George N Tzanakakis, Marie-Paule Mingeot-Leclercq (2006)  Water-soluble amphotericin B-polyvinylpyrrolidone complexes with maintained antifungal activity against Candida spp. and Aspergillus spp. and reduced haemolytic and cytotoxic effects.   J Antimicrob Chemother 57: 2. 236-244 Feb  
Abstract: OBJECTIVES: Poor solubility and toxicity severely hinder the clinical use of amphotericin B (AmB), in spite of its attractive chemotherapeutic properties. Water-soluble complexes of AmB and polyvinylpyrrolidone (AmB-PVP) could display lower cytotoxicity while maintaining antifungal activity. METHODS: AmB-PVP [with PVP of 10, 24 and 40 kDa (AC1, AC2 and AC4)] were compared with free AmB for (i) activity against Candida spp. (five albicans; nine non-albicans) and Aspergillus spp. (four strains), (ii) haemolysis of sheep red blood cells, and (iii) release of lactate dehydrogenase from J774 macrophages [with further comparison with free PVP and a liposomal formulation of amphotericin (AmBisome)]. RESULTS: MICs and MFCs of AC1, AC2 and AC4 against Candida spp. and of AC2 and AC4 against Aspergillus spp. were similar to those of AmB (and even lower for some Candida strains). Killing kinetics (24 h) were also similar. Haemolytic activity of AC2 and AC4 was 2-fold lower than that of free AmB. Cytotoxicity of AC2 towards J774 macrophages was 8-fold lower, and that of AC4 5-fold lower than that of AmB and not significantly different from that of AmBisome. The lower cytotoxicity of AC2, AC4 was correlated with a lower cellular accumulation of amphotericin. Spectroscopic analysis shows that the lower toxicity of AmB-PVP was not owing to significant change in the monomeric/polymeric forms ratio of the drug. CONCLUSIONS: AmB-PVP complexes compared favourably with AmB for antifungal activity, were less haemolytic and cytotoxic than AmB, and show a similar cytotoxicity profile to AmBisome.
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Zaxarenia Vlata, Filippos Porichis, George Tzanakakis, Aristidis Tsatsakis, Elias Krambovitis (2006)  A study of zearalenone cytotoxicity on human peripheral blood mononuclear cells.   Toxicol Lett 165: 3. 274-281 Sep  
Abstract: The mycotoxin zearalenone (ZEA) is a common contaminant of all major cereal grains worldwide with estrogenic and anabolic activity. We investigated the in vitro cytopathic effects of ZEA on freshly isolated human peripheral blood mononuclear cells (PBMC) in relation to proliferation and cell death patterns of untreated and mitogen-activated cells. The higher concentration of 30microg/ml ZEA was found to totally inhibit T and B lymphocyte proliferation from the stimulation with phytohemagglutinin and pokeweed mitogen. The inhibitory effects of ZEA were further related to cell necrosis/apoptosis. Flow cytometry analysis showed a distinct necrotic effect on PBMC, irrespective of mitogen stimulation, whereas apoptotic activity was less evident. Necrosis was observed in both the lymphocyte and monocyte/granulocyte gates. Measurements of ZEA-induced intracellular calcium ion (Ca(2+)) mobilization showed an increase of both Ca(2+) levels and the number of cells with high Ca(2+) only in the monocyte/granulocyte gated cells. Using phenylmethyl sulfonyl fluoride (PMSF), a serine protease inhibitor, and ammonium chloride (NH(4)Cl), a lysosomal inhibitor, both associated with cell necrosis inhibition, we showed that PMSF at 0.05mM and NH(4)Cl at 1 and 10mM reduced the cytopathic effects induced by 30microg/ml ZEA, whereas apoptosis was less affected. Expose of PBMC to 1microg/ml ZEA did not alter the viability of the cells. Our results suggest that high ZEA concentrations in the blood may well exert cytotoxic effects that merit further investigation.
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D Nikitovic, A Zafiropoulos, P Katonis, A Tsatsakis, A D Theocharis, N K Karamanos, G N Tzanakakis (2006)  Transforming growth factor-beta as a key molecule triggering the expression of versican isoforms v0 and v1, hyaluronan synthase-2 and synthesis of hyaluronan in malignant osteosarcoma cells.   IUBMB Life 58: 1. 47-53 Jan  
Abstract: Versican, a large sized chondroitin-sulphate proteoglycan (PG), and its binding partner, hyaluronan (HA), are extracellular matrix (ECM) components that play an essential role in transformed cell behavior. Expression of certain versican isoforms has been implicated in cell migration and proliferation of cancer cells and, on the other hand, disruption of HA synthesis by inhibiting hyaluronan synthase-2 (HAS2) expression in osteosarcoma cells by suppressing cell proliferation, invasiveness and motility. Considering that growth factors, such as TGF-beta, bFGF and PDGF-BB, are important regulators for the expression of the ECM macromolecules, in this study we examined the effect of these growth factors on the expression of the various versican isoforms, HA synthases as well as HA synthesis by MG-63 osteosarcoma cells and normal human osteoblastic periodontal ligament cells (hPDL). Real-time PCR and metabolic labelling followed by fine HPLC analysis coupled to radiochemical detection were the methods utilized. It was found that, contrary to normal hPDL cells, osteosarcoma MG-63 cells do not constitutively express the versican isoforms V0 and V1. Exogenous addition of TGF-beta2 stimulated the versican transcript levels mainly by forcing osteosarcoma cells to express V1 and V0 isoforms. PDGF-BB and bFGF had only minor effects in these cells. In hPDL cells a strong stimulation of the V3 transcript by all growth factors was observed. TGF-beta2 was also the major stimulator of HAS2 isoform expression as well as hyaluronan synthesis in osteosarcoma cells, while PDGF-BB exerted dominant influence on HAS2 isoform expression and hyaluronan biosynthesis by osteoblasts. The obtained results show for the first time that TGF-beta2 triggers the malignant phenotype pattern of versican and hyaluronan expression in human osteosarcoma cells and indicate that this growth factor may account for the metastatic potential of these cells.
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Constantine I Vardavas, Manolis N Tzatzarakis, Aristeidis M Tsatsakis, Dimitrios Athanasopoulos, Evaggelia Balomenaki, Manolis K Linardakis, Anthony G Kafatos (2006)  Biomarkers of passive smoking among Greek preschool children.   Eur J Pediatr 165: 12. 891-896 Dec  
Abstract: BACKGROUND: Greece has the highest adult smoking prevalence in the European Union, affecting not only those who smoke but also threatening the health of those who are involuntarily exposed to passive smoke, especially young Greek children. OBJECTIVE: The aim of this study was to quantify passive smoking biomarkers (serum nicotine and cotinine levels) among preschool children in Crete in relation to parental smoking habits. METHODS: All children enrolled in kindergarten in western Crete (1,757 preschool children and 2,809 parents) were interviewed during the 2004-2005 Cretan health promotion programme out of which a sample of 81 children was randomly selected according to parental smoking status and blood samples for cotinine and nicotine assay were taken. RESULTS: The geometric means of serum nicotine values in children with both parents current smokers and in those with both parents non-smokers were 0.71 ng/ml (95%CI 0.62, 0.80) and 0.59 ng/ml (95%CI 0.49, 0.69), respectively, (p=0.073). Cotinine geometric mean values were found at 1.69 ng/ml (95%CI 0.93, 3.06) and 0.15 ng/ml (95%CI 0.09, 0.28), respectively, (p<0.001). Girls with smoker parents had also greater cotinine geometric mean values than boys (3.35 versus 0.85 ng/ml, respectively, p=0.018). CONCLUSION: Our findings prove that Greek preschool children, especially young girls, are exposed to substantial levels of passive smoke which therefore stresses the need for immediate action so as to prevent the predisposition and early addiction of Greek preschool children to tobacco.
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E Fthenou, A Zafiropoulos, A Tsatsakis, A Stathopoulos, N K Karamanos, G N Tzanakakis (2006)  Chondroitin sulfate A chains enhance platelet derived growth factor-mediated signalling in fibrosarcoma cells.   Int J Biochem Cell Biol 38: 12. 2141-2150 07  
Abstract: Platelet derived growth factor is involved in the autocrine growth stimulation of malignant cells, the stimulation of angiogenesis and the recruitment and regulation of tumor fibroblasts. PDGF has been shown to physically interact with glycosaminoglycans which are abundant in the fibrosarcoma cell microenvironment. Aim of the present study was to examine the effects of glycosaminoglycans on the mitogenic function of platelet derived growth factor in two human fibrosarcoma cell lines (B6FS, HT1080). For this purpose exogenously added glycosaminoglycans, regulators of endogenous glycosaminoglycan synthesis (sodium chlorate as selective inhibitor and beta-D-xyloside as a stimulator) and specific glycosidases to cleave cell-associated glycosaminoglycans, were utilized. Platelet derived growth factor demonstrated a growth stimulating effect on B6FS, whereas no effect was evident on HT1080 fibrosarcoma cells. Beta-D-xyloside had no effect on the basal level or the platelet derived growth factor-induced cell proliferation, whereas sodium chlorate severely reduced the basal level of proliferation in both cell lines. Significant co-stimulatory effects of chondroitin sulfate A in combination with platelet derived growth factor BB on the growth of HT1080 and B6FS cells were found. The co-stimulatory effect of chondroitin sulfate A was not due to transcriptional up regulation of platelet derived growth factor receptors genes, but rather to more efficient signalling of tyrosine kinase receptors. In conclusion, this study shows that chondroitin sulfate A can enhance the mitogenic activity of platelet-derived growth factor in fibrosarcoma cells utilizing a pathway which involves tyrosine kinases. This result introduces a new modulating role for chondroitin sulfate in signalling pathways critical for cancer growth.
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2005
M A Savvopoulos, E Pallis, M N Tzatzarakis, I A Dialyna, G N Tzanakakis, A M Tsatsakis (2005)  Legal issues of addiction assessment: the experience with hair testing in Greece.   J Appl Toxicol 25: 2. 143-152 Mar/Apr  
Abstract: The purpose of this paper is to present Greek law and legislation for crimes and felonies regarding drugs of abuse and the interpretation of hair testing results with respect to Greek law. Details (such as the process, the decision and the competence of the Court, the police record, the indictment, the expert reports, the defendant's individuality, the crimes and the penal confrontal and many others) from legal cases related to toxicomany and its judicial verification were collected and analysed. Laboratory data of cases concerning the laboratory evaluation of toxicomany in addicts and also occasionally the legal course of cases with addict defendants are presented. In four representative cases segmental hair analysis proved that, for as long as the individuals were imprisoned, findings with drug substances corresponding to that period were lesser or practically absent compared with samples corresponding to the time out of prison, which showed increased drug abuse. Hair analysis provides information on chronic exposure rather than acute poisoning. Its detection window varies from some days to months or even years. The procedure that the law lays down in many cases is insufficient and in most cases impossible to abide by. When the medical examiner is not able to decide if the claim of toxicomany is real, segmental hair analysis may be the only way to prove it. In other cases where the medical examiner is able to diagnose the addiction, a segmental hair analysis is necessary because it can show long-term drug abuse.
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Stavros Sifakis, Emmanuel Angelakis, Antonis Makrigiannakis, Irene Orfanoudaki, Maria Christakis-Hampsas, Pavlos Katonis, Aristidis Tsatsakis, Eugenios Koumantakis (2005)  Chemoprophylactic and bactericidal efficacy of 80 mg gentamicin in a single and once-daily dosing.   Arch Gynecol Obstet 272: 3. 201-206 Sep  
Abstract: OBJECTIVE: The objective was to examine the biodistribution, the chemoprophylactic, and the bactericide efficacy of 80-mg gentamicin single or once-daily dosing. STUDY DESIGN: Ninety-six patients who had had cesarean section or gynecological surgery received 80 mg gentamicin for chemoprophylaxis. A second group of 92 patients with Gram-negative infection received once-daily 80-mg gentamicin intramuscularly, combined with cefoxitin or ceforanide, for 5 days. Gentamicin serum and tissue concentration was determined 1 h after the first administration. RESULTS: The chemoprophylactic efficacy of gentamicin was 93.7%. The treatment efficacy was high in patients with chorioamnionitis and endometritis (92.9%), moderate in those with wound infection (69.5%), and less effective in those with septicemia (55.6%). Twenty-six percent of patients continued with antibiotics for infection control. The mean serum level was 4.48+/-0.49 and 5.56+/-0.66 microg/ml in obstetrical and gynecological patients respectively (p>0.05). Serum levels >4 microg/ml were achieved in 91% of patients. CONCLUSIONS: A single dose of 80 mg gentamicin offers chemoprophylaxis and achieves therapeutic serum-concentrations 1 h after administration. The 5-day combination of once-daily 80 mg gentamicin with a second-generation cephalosporin is effective in patients with chorioamnionitis and endometritis, but only moderately effective in those with wound infections and septicemia.
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Zaharenia Vlata, Filippos Porichis, George Tzanakakis, Aristidis Tsatsakis, Elias Krambovitis (2005)  In vitro cytopathic effects of mycotoxin T-2 on human peripheral blood T lymphocytes.   Toxicol Lett 160: 1. 60-68 Dec  
Abstract: The trichothecene mycotoxin T-2 is reported to exhibit immunotoxic activity. The potential presence of T-2 in foods renders it as public health hazard and its toxicity needs to be better understood. We investigated the in vitro effects of T-2 at sub-toxic (0.1 ng/ml) and toxic (10 ng/ml) levels on freshly isolated human peripheral blood lymphocytes (PBLs). We observed no direct influence on untreated PBLs. The toxic dose of T-2, however, totally inhibited phytohemagglutinin-induced T lymphocyte proliferation and caused early apoptosis that peaked after 8h of exposure. Both major T lymphocyte subsets (CD4+ and CD8+) were affected as they appeared to show a positive response to T-2 at 8h followed by their sharp reduction after 96 h. Further investigation on the naïve (CD45RA+) and memory (CD45RO+) subpopulations confirmed these observations and indicated that T-2 affected equally all the subpopulations studied, although PHA preferentially stimulated CD45RO+ T lymphocytes. Sub-toxic T-2 appeared to exhibit co stimulatory properties to PHA-stimulated cells. These results support the hypothesis that T-2 affects the activation-induced cell death mechanism of T lymphocytes.
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Maria Tutudaki, Aristidis M Tsatsakis (2005)  Pesticide hair analysis: development of a GC-NCI-MS method to assess chronic exposure to diazinon in rats.   J Anal Toxicol 29: 8. 805-809 Nov/Dec  
Abstract: The present study aimed to improve the gas chromatography-mass spectrometry (GC-MS) method, already developed in our laboratory, for trace analysis of diazinon in hair. Furthermore, it aimed to compare the disposition of the pesticide in the hair of two different animal species, one susceptible to diazinon toxicity and one resistant, under identical experimental conditions. Sprague Dawley rats were systemically exposed to two dose levels (6 mg/kg/day and 3 mg/kg/day) of the pesticide, through their drinking water, for a period of one and a half months. Hair samples from the back of the rats were removed before commencing the experiment and at the end of the dosing period. Diazinon was selectively isolated from pulverized hair, sample or spiked, by stepwise consequent extractions with methanol and ethyl acetate and quantified by GC-negative chemical ionization-MS. It was found that the concentration of diazinon in the hair of exposed animals was dose dependent and was found to be 0.24 +/- 0.01 ng/mg (n = 5) and 0.53 +/- 0.05 ng/mg (n = 5) for the low and high dosage, respectively. The concentration in both dose groups was much higher than the corresponding rabbit hair (rabbits were exposed to the pesticide under similar experimental conditions) as previously reported. Our results strongly point to the possibility of using hair analysis for low-level exposure monitoring of diazinon.
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D Nikitovic, A Zafiropoulos, G N Tzanakakis, N K Karamanos, A M Tsatsakis (2005)  Effects of glycosaminoglycans on cell proliferation of normal osteoblasts and human osteosarcoma cells depend on their type and fine chemical compositions.   Anticancer Res 25: 4. 2851-2856 Jul/Aug  
Abstract: Osteoblastic cells produce a complex extracellular matrix (ECM) composed of a mixture of proteoglycans (PGs), collagens and non-collagenous proteins. The interaction of proteoglycans with matrix effector macromolecules via either their glycosaminoglycan (GAG) chains or their protein core is critical in regulating a variety of cellular events. Alterations in the structural composition of the GAG/PG component of the ECM may have important consequences on cell proliferation and/or differentiation. Human osteoblasts and two osteosarcoma cell lines, able to produce galactosaminoglycan (GalAGs) and heparan sulphate (HS)-containing proteoglycans, were treated with their main GAG chain types, and the effects on cell growth were examined. Chondroitin sulphate (CSA) and dermatan sulphate (DS) inhibited cell proliferation of all osteoblastic cell lines at high concentration (100 microg/ml). DS showed the stronger inhibitory effect, probably due to the presence of flexible IdoA residues that provide a greater variety in conformation to these macromolecules. Heparin strongly inhibited the proliferation rates of both normal osteoblasts and transformed osteoblastic cells at concentrations > or = 1 microg/ml. The presence of large amounts of IdoA-derived trisulphated disaccharides, responsible for the overall negative charge of heparin, should be considered as a critical factor for the inhibition of cell proliferation. The obtained results suggest that matrix GAGs are factors which affect cell growth of both malignant and normal cells of the osteoblastic lineage in a concentration-dependent manner. This effect is closely related to the fine chemical structure of GAGs, i.e. the presence of L-iduronic acid and the degree of sulphation.
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Nikolas C Papanikolaou, Eleftheria G Hatzidaki, Stamatis Belivanis, George N Tzanakakis, Aristidis M Tsatsakis (2005)  Lead toxicity update. A brief review.   Med Sci Monit 11: 10. RA329-RA336 Oct  
Abstract: Lead is a metal which has been associated with human activities for the last 6000 years. In ancient civilizations, uses of lead included the manufacture of kitchen utensils, trays, and other decorative articles. However, lead is also toxic to humans, with the most deleterious effects on the hemopoietic, nervous, reproductive systems and the urinary tract. The main sources of lead exposure are paints, water, food, dust, soil, kitchen utensils, and leaded gasoline. The majority of cases of lead poisoning are due to oral ingestion and absorption through the gut. Lead poisoning in adults occurs more frequently during exposure in the workplace and primarily involves the central nervous system. Symptoms of hemopoietic system involvement include microcytic, hypochromic anemia with basophilic stippling of the erythrocytes. Hyperactivity, anorexia, decreased play activity, low intelligence quotient, and poor school performance have been observed in children with high lead levels. Lead crosses the placenta during pregnancy and has been associated with intrauterine death, prematurity, and low birth weight. In 1991, the Centers for Disease Control and Prevention in the USA redefined elevated blood lead levels as those > or = 10 microg/dl and recommended a new set of guidelines for the treatment of lead levels > or =15 microg/dl.
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2004
Evangelia C Mantzouranis, George K Bertsias, Eleftherios G Pallis, Aristidis M Tsatsakis (2004)  Hair analysis differentiates chronic from acute carbamazepine intoxication.   Pediatr Neurol 31: 1. 73-75 Jul  
Abstract: This is a report of a 12-year-old epileptic child undergoing chronic treatment with carbamazepine who was found comatose. He was considered to have acute severe drug toxicity. Measurement of carbamazepine concentration in the patient's hair segments together with the carbamazepine blood levels were both important in determining the chronic nature of the patient's intoxication.
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I E Liapakis, I Kottakis, M N Tzatzarakis, A M Tsatsakis, M S Pitiakoudis, P Ypsilantis, R W Light, C E Simopoulos, D E Bouros (2004)  Penetration of newer quinolones in the empyema fluid.   Eur Respir J 24: 3. 466-470 Sep  
Abstract: The degree of penetration of newer quinolones into the pleural fluid has not been studied. The objective of the present study was to determine the degree to which moxifloxacin and levofloxacin penetrate into empyemic pleural fluid using a new rabbit model of empyema. An empyema was created via the intrapleural injection of turpentine (1 mL), followed 24 h later by instillation of 2 mL (1 x 10(10)) Escherichia coli bacteria (ATCC 35218) into the pleural space of New Zealand white rabbits. After an empyema was verified by thoracentesis and pleural fluid analysis, moxifloxacin and levofloxacin (25 mg.kg(-1) for both, i.v.) were administered. Antibiotic levels were determined in samples of pleural fluid and in blood collected serially over 12 h. Antibiotic levels were measured using HPLC. Each of the antibiotics penetrated well into the empyemic pleural fluid. Antibiotic penetration was the greatest for moxifloxacin (area under the curve (AUC) for pleural fluid/blood (AUCPF/AUCblood) ratio=1.37) followed by levofloxacin (ratio=1.13). The time to equilibration between the pleural fluid and blood antibiotic levels was more rapid for moxifloxacin (3.9 h) than for levofloxacin (4.4 h). With moxifloxacin, the peak pleural fluid concentration (Cmax,PF) was 2.77 microg.mL(-1) and occurred at a time to maximum pleural fluid concentration (Tmax,PF) of 6 h after infusion and decreased thereafter. The peak blood concentration (Cmax,blood) was 4.81 microg.mL(-1) at 1 h after administration. With levofloxacin, the peak pleural fluid level (Cmax,PF=1.39 microg.mL(-1)) occurred at 6 h (Tmax,PF=6 h) after infusion. The Cmax,blood was 1.88 microg.mL(-1) at 1 h after administration. In conclusion, differences were found in the degree of penetration of the two quinolones into infected pleural fluid in rabbits. The clinical significance of these differences is unknown. More studies are needed to evaluate the pharmacokinetic parameters in the pleural space in humans.
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Ioanna Dialyna, George Tzanakakis, George Dolapsakis, Aristidis Tsatsakis (2004)  A tetranucleotide repeat polymorphism in the CYP19 gene and breast cancer susceptibility in a Greek population exposed and not exposed to pesticides.   Toxicol Lett 151: 1. 267-271 Jun  
Abstract: Epidemiological studies have suggested that hormones, genetic factors, and environmental agents are significant risk factors in breast carcinogenesis. Some pesticides have the ability to act as xenoestrogens in vivo. The CYP19 gene encodes the aromatase enzyme which is involved in the estrogens biosynthetic pathways. We have assessed the frequency alleles of a (TTTA)(n) repeat of CYP19 gene in breast cancer patients which were either exposed or not exposed to specific pesticides. No differences were observed in the distribution of the alleles between the two groups showing that the polymorphism does not have a significant functional role on the aromatase activity. When compared to healthy control Greek women group, only the (TTTA)(10) repeat variant presented a non-significant increased risk in breast cancer susceptibility [odds ratio (OR): 2.46, P>0.05 ]. Lack of strong association suggests that the polymorphic TTTA short tandem repeat of CYP19 gene may have not a functional effect on the enzyme's activity and thus its role in the development of breast cancer remains unclear.
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George K Bertsias, Pavlos Katonis, George Tzanakakis, Aristidis M Tsatsakis (2004)  Review of clinical and toxicological features of acute pesticide poisonings in Crete (Greece) during the period 1991-2001.   Med Sci Monit 10: 11. CR622-CR627 Nov  
Abstract: BACKGROUND: In Crete, the largest island of Greece, many pesticide formulations are increasingly used in agriculture in order to raise crop production. This study reviews a number of pesticide poisoning cases registered at the Center of Toxicology and Forensic Sciences Research at the University of Crete between 1991 and 2001. MATERIAL/METHODS: The medical records and toxicological data of the pesticide poisonings are presented. The analyzed samples were mainly blood and/or urine, but also gastric fluids and other tissues. Analysis involved a variety of techniques. RESULTS: Eleven poisonings caused by paraquat (7 men, 4 women, aged 15-58 years) are reported, five of which had fatal outcome. Initial paraquat plasma levels ranged between 0.4-165 pg/ml. Thirteen intoxications due to various organophosphorous agents are presented (11 men, 2 women, aged 13-69 years). Pesticide blood levels upon admission ranged from 1.0-108 pg/ml and there were six fatalities. Carbamate poisonings (4 men, 2 women, aged 32-60 years) were caused by methomyl (initial blood levels 1.6-57 mg/l) and resulted in death. A case of methyl bromide intoxication is also presented. CONCLUSIONS: The results of the study highlight the toxic and potentially lethal effects of pesticide formulations used in agriculture. Special seminars should be run to educate farmers on the proper use of these agents and the supply of pesticides should be restricted to those who follow all safety measures. Physicians should be trained to promptly identify and treat pesticide intoxications.
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I N Tsakiris, T G Danis, I A Stratis, D Nikitovic, I A Dialyna, A K Alegakis, A M Tsatsakis (2004)  Monitoring of pesticide residues in fresh peaches produced under conventional and integrated crop management cultivation.   Food Addit Contam 21: 7. 670-677 Jul  
Abstract: The frequency and severity of crop protection product (pesticide) contamination of peaches grown conventionally were compared with those of peaches grown by integrated crop management (ICM). The peach samples (n = 150) were collected preharvest (June-August 2001) from both conventional (n = 55) and ICM (n = 95) cultivations from the Pella and Imathia districts of Macedonia, Northern Greece. The residue levels of selected insecticides, fungicides and acaricides in peach samples were determined by gas chromatography-mass spectrometry following solid-phase extraction. The concentrations of all detected pesticides were lower than the maximum residue limits (MRLs) in all peach samples grown with the ICM system (p<0.001). However, chlorpyrifos residues at levels higher than the MRLs were detected in four peach samples (i.e. 7% of the total samples) grown by the conventional system. Comparing the results for both cultivation methods with the reported average percentage (3.6%) of fruit samples with pesticide residues above the MRLs (European Union report for Greece in 2001), it was concluded that the initial implementation of the ICM in Greece was successful. The present study indicates that ICM cultivation has a higher efficiency in terms of product safety and quality. Furthermore, the results suggest that the application of conventional cultivation requires continuous monitoring of various crop protection product levels.
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Aristidis Tsatsakis, Maria Tutudaki (2004)  Progress in pesticide and POPs hair analysis for the assessment of exposure.   Forensic Sci Int 145: 2-3. 195-199 Oct  
Abstract: The present paper reviews the work that has been done in the field of pesticide and persistent organic pollutants (POPs) hair analysis during the last 15 years. It summarizes the compounds of interest, the methods of analyte extraction from the hair matrix, the analytical techniques employed and the results obtained. The most widely studied POPs are the polychlorinated dibenzodioxins (PCDDs), the dibenzofurans (PCDFs) the co-planar biphenyls (co-PCBs) and total biphenyls (PCBs). The most widely studied pesticides are the organochlorine ones, like the hexachlorocyclohexanes and the DDTs, which nowadays are only found as environmental pollutants, some organophosphates, selected pyrethroids and the carbamate methomyl. The most widely applied technique was gas chromatography (GC) coupled to mass spectrometry (MS). Other detectors like the ECD in the case of organochlorine analysis and the NPD in the case of organophosphate analysis were also used. The presented data concern human and animal studies. The levels of DDTs detected in hair were between 19 and 400 ng/g, of co-PCBs 0.27 and 0.45 ng/g, of total PCBs 5-13 ng/g of PCDDs and PCDFs 0.1-10 pg/g of lindane 20-400 ng/g of HCHs 14-40 ng/g of diazinon 110-520 ng/g and of methomyl 900-1800 ng/g. These results strongly support the possibility of using hair as a suitable indicator for the assessment of long-term exposure to POPs and pesticides.
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2003
A M Tsatsakis, I N Tsakiris, M N Tzatzarakis, Z B Agourakis, M Tutudaki, A K Alegakis (2003)  Three-year study of fenthion and dimethoate pesticides in olive oil from organic and conventional cultivation.   Food Addit Contam 20: 6. 553-559 Jun  
Abstract: Residues of fenthion and dimethoate pesticides were determined in organic and conventional olive oils by liquid-liquid and solid-phase extractions with subsequent gas chromatography and mass spectrometric analysis. The olive oil samples were collected from Crete during 1997-99. The average concentrations of fenthion in conventional olive oils were 0.1222, 0.145 and 0.1702 mg x kg(-1), and for dimethoate were 0.0226, 0.0264 and 0.0271 mg x kg(-1) for 1997, 1998 and 1999, respectively. The average concentrations of fenthion in organic olive oils were 0.0215, 0.0099 and 0.0035 mg x kg(-1) for 1997, 1998 and 1999, while for dimethoate they were 0.0098, 0.0038 and 0.0010 mg x kg(-1), respectively. All the olive oils contained residue levels lower than the maximum residue levels according to the FAO/WHO Codex Alimentarius. The organic olive oil contained significantly lower concentrations of the two pesticides. The levels of fenthion and dimethoate in organic olive oils exhibited a decreasing trend following the implementation of the new cultivation method. We propose procedures that should be established in the organic cultivation in order to maximize its effectiveness.
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Dragana Nikitovic, Aristidis M Tsatsakis, Nikos K Karamanos, George N Tzanakakis (2003)  The effects of genistein on the synthesis and distribution of glycosaminoglycans/proteoglycans by two osteosarcoma cell lines depends on tyrosine kinase and the estrogen receptor density.   Anticancer Res 23: 1A. 459-464 Jan/Feb  
Abstract: The soy isoflavone genistein is a phytochemical which can affect the proliferation of both normal and cancer cells. The specific inhibition of protein tyrosine kinase (PTK) by which it effects the proliferation of cancer cells is a well-known mechanism of its action. Glycosaminoglycans (GAGs)/proteoglycans (PGs) are considered to be of great importance in the development and progression of cancer. The synthesis of GAGs by two osteosarcoma cell lines, MG-63 and SAOS-2, which differ in the density of estrogen receptors (ER) they express, and the effects of genistein on their synthesis and distribution among culture medium and cell membrane were studied. The obtained results showed that both cell lines synthesized extracellular hyaluronan (HA) and both extracellular and cell-associated galactosaminoglycans (GalAGs) and heparan sulfate (HS). Even though both cell lines synthesized considerable amounts of PGs, the SAOS-2 cells produced HA, GalAGs and HS at considerably lower rates than the MG-63 cells. The inhibitory effect of genistein on the synthesis of both extracellularly secreted and cell-associated GAGs/PGs in SAOS-2 2 cells was found to be dose-dependent and mediated most probably by a PTK mechanism. The synthesis of GAGs/PGs by the MG-63 cells in the presence of genistein was dependent on their type and localization, suggesting that a more complex mechanism regulates the PG synthesis. This may well involve the effect of genistein via the estrogen receptors, which are present in much higher density in MG-63 cells as compared to SAOS-2 cells.
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Maria Tutudaki, Andreas K Tsakalof, Aristidis M Tsatsakis (2003)  Hair analysis used to assess chronic exposure to the organophosphate diazinon: a model study with rabbits.   Hum Exp Toxicol 22: 3. 159-164 Mar  
Abstract: The main purpose of the present study was to determine whether hair analysis would be a suitable method to assess chronic exposure of rabbits to the pesticide diazinon. A controlled study was designed, in which white rabbits of the New Zealand variety were systemically exposed to two dosage levels (15 mg/kg per day and 8 mg/kg per day) of the pesticide, through their drinking water, for a period of 4 months. Hair samples from the back of the rabbits were removed before commencing the experiment and at the end of the dosing period. Parallel experiments with spiked hair were carried out in order to design a simple and efficient method of extraction of diazinon from hair. The hair was pulverized in a ball mill homogenizer, incubated in methanol at 37 degrees C overnight, liquid-liquid extracted with ethyl acetate and measured by chromatography techniques (GC-NPD and GC-MS) for confirmation. The concentration of the diazinon in the hair of the exposed animals ranged from 0.11 to 0.26 ng/mg hair. It was concluded that there is a relationship between the administered dose and the detected pesticide concentration in hair. Finally, it seems that hair analysis may be used to investigate chronic exposure to the pesticide.
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George N Tzanakakis, Andrew N Margioris, Aristidis M Tsatsakis, Michael P Vezeridis (2003)  The metastatic potential of human pancreatic cell lines in the liver of nude mice correlates well with cathepsin B activity.   Int J Gastrointest Cancer 34: 1. 27-38  
Abstract: BACKGROUND: Cathepsin B, a lysosomal cysteine protease, has a major role in the mechanisms of tumor metastasis. The aim of the present work was to examine the correlation between cathepsin B activity and the metastatic potential of human pancreatic cancer. METHODS: The primary cell line COLO 357 and the derivative tumor cell lines FG, L3.1, L3.2, L3.3, L3.4, and L3.5, which are characterized by progressively increasing metastatic potential, were injected intrasplenically in the athymic mice. Cathepsin B activity, metastasis, and ultrastructural characteristics were assessed. RESULTS: An increased number of liver tumor nodules was observed with each subsequent intrasplenic inoculation (p = 0.001), associated with lymph node, splenic, and pancreatic involvement. Cathepsin B activity progressively increased (p = 0.001) and was strongly positively correlated with the metastatic potential. However, no correlation was found between the metastatic potential and ultrastructural characteristics. CONCLUSIONS: These findings further support the central role of cathepsin B in metastasis in a combined in vitro/in vivo model.
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2002
George I Hatzidakis, Aristidis M Tsatsakis, Elias K Krambovitis, Apostolos Spyros, Sergei A Eremin (2002)  Use of L-lysine fluorescence derivatives as tracers to enhance the performance of polarization fluoroimmunoassays. A study using two herbicides as model antigens.   Anal Chem 74: 11. 2513-2521 Jun  
Abstract: Fluorescence polarization immunoassay (FPIA) is a convenient homogeneous assay, the use of which is restricted in environmental analysis by low sensitivity and matrix effects. We selected the herbicides 2,4D and 2,4,5T to synthesize new L-lysine-based fluorescent tracers using solid-phase chemistry. In addition, three different immunogens of 2,4,5T were prepared for immunization and antibody production. The new tracers and antibodies were adapted to FPIA. Tracers with the hapten attached to the alpha-aminogroup of L-lysine and fluorescein to the e-amino group exhibited at least a 5-fold increased sensitivity when compared to the previously reported ethylenediamine-based tracer (2,4D-EDA-F). The isomeric structure (hapten attached to the e-amino and fluorescein to the alpha-amino group) appeared 7.6 times less sensitive, and all other alternative structures exhibited even lower sensitivities. This observation was confirmed against the monoclonal anti-2,4D antibody E2/G2 and polyclonal anti-2,4,5T antibodies. The affinity constant of 2,4D-EDA-F with E2/G2 was 8.1 times higher when compared with the new tracer, suggesting the more specific nature of the L-lysine-based tracer, the use of which leads to a more sensitive assay. This type of tracer could improve performance and lower substantially the detection limits of FPIAs.
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Adrian Covaci, Maria Tutudaki, Aristidis M Tsatsakis, Paul Schepens (2002)  Hair analysis: another approach for the assessment of human exposure to selected persistent organochlorine pollutants.   Chemosphere 46: 3. 413-418 Jan  
Abstract: Hair analysis was used for the assessment of exposure to organochlorine pollutants in specimens from Greece, Romania and Belgium. A simple method (using 3 N HCI as incubation reagent, liquid-liquid extraction with hexane/ dichloromethane (DCM), alumina/acid silica clean-up and GC-ECD/GC-MS analysis) was used for screening of specimens. The highest organochlorine load (up to 148 ng/g hair for the sum of PCB, DDT and hexachlorocyclohexane (HCH) isomers) was found in samples from a group of Greek women with past occupational exposure to pesticides. DDTs were the main organochlorine pollutants in Greek samples (up to 70%), while in Belgian hair samples their contribution was reduced to 40%. PCB mean concentration was higher in Belgian specimens (up to 14 ng/g hair). Lindane (y-HCH) was the main HCH isomer found in the samples (up to 82% in the Greek samples). Contribution of p,p'-DDT to the sum of DDTs was higher in Greek samples and indicates recent exposure to technical DDT. Similar PCB 153/sum PCBs ratios were found for each of the three countries suggesting similar sources of pollution with PCBs (mainly dietary). Artificially coloured hair samples were found to have lower, but not statistically significant concentrations of organochlorine pollutants than the non-coloured hair.
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Ekatherina Charvalos, Aristeidis Tsatsakis, Manolis Tzatzarakis, George Dolapsakis, John Stiakakis (2002)  New nystatin polymeric complexes and their in vitro antifungal evaluation in a model study with Fusarium oxysporum.   Mycopathologia 153: 1. 15-19  
Abstract: Six water-soluble nystatin-polyvilnylpyrrolidone complexes with respective MW of 10 kDa (NC1), 25 kDa (NC2), 30 kDa (NC3), 40 kda (NC4), 90 kDa (NC5), 360 kDa (NC6) were synthesized. The activity of the complexes was compared with that of nystatin against growth and spore germination of Fusarium oxysporum f.sp. radiciscucumerinum. The ED50 value (effective dose) of free nystatin in aqueous solution on growth inhibition on solid medium was determined at 35.7 ppm. The ED50 of the complexes NC3, NC4, NC5, and NC6 ranged from 2.2 to 4 times lower than that of nystatin. The NC6 complex exhibited the highest activity, followed by NC5, NC4, and NC3. The activities of NC1 and NC2 were about 3 and 1.7 times higher than nystatin respectively in the same in vitro model. The complexes NC6. NC1 and NC4 were 25.4, 13.6 and 6.9 times more active respectively than nystatin against spore germination of E oxysporum. The activity of the nystatin complexes was dependent on the molecular weight of the polymeric carrier.
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Stavroula Baritaki, George N Tzanakakis, John Alifragis, Alexis Zafiropoulos, Ravshan I Tashmukhamedov, Aristidis Tsatsakis, Mikhail I Shtilman, Apostolos K Rizos, Elias Krambovitis (2002)  Light scattering and in vitro biocompatibility studies of poly (vinyl pyrrolidone) derivatives with amino-acid-dependent groups.   J Biomed Mater Res 63: 6. 830-837  
Abstract: Two poly (vinyl pyrrolidone) (PVP) families with amino-acid residues (glycine, beta-alanine, gamma-aminobutiric acid and epsilon-aminocaproic acid) on the base of the co-polymer N-vinyl pyrrolidone and allyl-glycidyl ether (VP-AGE) and on the base of epoxidized PVP (EPVP) were synthesized. Static and dynamic light scattering measurements of these PVP derivatives in water showed that their structure/ behavior were similar to that of PVP. The bioreactivity was also similar to that of PVP. Further investigation of the immunoreactive properties of the derivatives in in vitro proliferation assays with fresh normal human peripheral blood lymphocytes and monocytes led to the determination of a costimulatory profile for each derivative in terms of polyclonal stimulation, specific antigen presentation, and immunoglobulin secretion. This profile allows the selection of an appropriate derivative as a carrier that would suit the immunoreactivity needs of the immobilized ligand.
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A M Tsatsakis, G K Bertsias, V Liakou, I N Mammas, I Stiakakis, G N Tzanakakis (2002)  Severe fenthion intoxications due to ingestion and inhalation with survival outcome.   Hum Exp Toxicol 21: 1. 49-54 Jan  
Abstract: Two cases of severe fenthion intoxication are presented. The first is a case of a psychiatric patient who attempted suicide with ingestion of the compound, and the second case was of a child exposed to the chemical agent by air spraying. Both patients were treated in the intensive care unit with atropine and pralidoxime and finally survived. Fenthion blood levels on admission were 2.7 and 0.95 microg/mL, respectively. Different concentrations of pralidoxime were added to the first patient's poisoned serum in order to assess in vitro the effect of pralidoxime on cholinesterase reactivation. The clinical and toxicological data of the poisonings are discussed, as well as the potential therapeutic use of pralidoxime in organophosphate intoxication.
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George N Tzanakakis, Elias Krambovitis, Aristidis M Tsatsakis, Michael P Vezeridis (2002)  The preventive effect of ketoconazole on experimental metastasis from a human pancreatic carcinoma may be related to its effect on prostaglandin synthesis.   Int J Gastrointest Cancer 32: 1. 23-30  
Abstract: BACKGROUND: Arachidonic acid metabolites known to affect platelet function also interfere with tumor growth and metastases. The purpose of this study was to evaluate the anti-metastatic potential of ketoconazole, a thromboxane synthetase and 5-lipoxygenase inhibitor, on hepatic metastasis from a human pancreatic adenocarcinoma in nude mice and its effect on serum prostaglandin levels. METHODS: The human pancreatic tumor cells (RWP-2) were injected intrasplenically in nude mice grouped into control, ketoconazole (270 microg), ketoconazole (360 microg), and ketoconazole (540 microg). The agent was administered intraperitoneally 30 min before and every 24 h after the tumor cell inoculation for 8 days. In a separate experiment thromboxane B2 (TxB2), prostaglandin D2 (PGD2), prostaglandin E2 (PGE2) and 6-Keto-F1a (stable prostacyclin derivative) were measured on blood from controls, tumor bearing animals and animals bearing tumors treated with 270 microg of ketoconazole. RESULTS: Statistically significant differences were observed between the control and three-treatment groups on the reduction of liver tumor nodules (p < 0.001), and in the liver surface areas occupied by tumor (p < 0.001). The TxB2 levels decreased from 150.6 ng/mL in the tumor bearing to 104.8 ng/mL in the ketoconazole treated animals (p < 0.05). PGD2, PGE2 and 6-keto-F1a levels increased to 7.1 ng/mL, 8.3 ng/mL, and 13.6 ng/mL from 3 ng/mL, 5.8 ng/mL, and 0.02 ng/mL respectively (p < 0.001). CONCLUSIONS: These results indicate that ketoconazole significantly reduced hepatic metastases from the human pancreatic carcinoma RWP-2 in the nude mouse model, and inhibited thromboxane B2 formation, potentiating a concomitant redirection of platelet endoperoxide metabolism into PGD2, PGE2, and 6-keto-F1a. It is hypothesized that the changes in the arachidonic acid metabolism mediate the ameliorating effect of ketoconazole on experimental hepatic metastasis.
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Theoni N Mitropoulou, George N Tzanakakis, Dragana Nikitovic, Aristidis Tsatsakis, Nikos K Karamanos (2002)  In vitro effects of genistein on the synthesis and distribution of glycosaminoglycans/proteoglycans by estrogen receptor-positive and -negative human breast cancer epithelial cells.   Anticancer Res 22: 5. 2841-2846 Sep/Oct  
Abstract: Genistein, a soy isoflavone, affects the proliferation of both estrogen receptor (ER)-positive and ER-negative cancer cells. Glycosaminoglycans (GAGs)/proteoglycans (PGs) are considered to be of great importance in the treatment of cancer. The synthesis of GAGs by two human breast cancer epithelial cell lines, the ER-positive MCF-7 and the ER-negative BT-20, was studied under the effects of genistein, and their distribution in the culture medium and the cell membranes was determined. The results obtained show that both cell lines synthesize extracellular hyaluronic acid (HA) and both extracellular and cell-associated galactosaminoglycans (GalAGs) and heparan sulphate (HS). The MCF-7 cell line synthesizes HA, GalAGs and HS at considerably lower rates than the BT-20 cell line. The effect of genistein on the synthesis of extracellularly secreted GAGs/PGs by ER-positive MCF-7 cells is dose-dependent and follows two mechanisms; one at low concentrations (< or = 35 microM) mediated via the estrogen receptor and the other at higher concentrations via protein tyrosine kinase (PTK). The synthesis of cell-associated GAGs/PGs by ER-positive MCF-7 cells and of both secreted and associated with the cell membrane GAGs/PGs by ER-negative BT-20 cells is mediated by a PTK mechanism. It is concluded that genistein affects the synthesis of GAGs/PGs, by breast cancer epithelial cells depending on the presence or absence of estrogen receptor and the localisation of PGs.
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2001
E N Michalodimitrakis, D D Tsiftsis, A M Tsatsakis, I Stiakakis (2001)  Sudden cardiac death and right ventricular dysplasia.   Am J Forensic Med Pathol 22: 1. 19-22 Mar  
Abstract: Right ventricular cardiomyopathy dysplasia, now a well-established clinical and morphologic entity, was first reported in the medical literature in 1982. The cases of sudden death of two young men are here reported, with macroscopic and histologic findings. The anatomical explanation of such death was a fibrotic, lipomatous, or fibrolipomatous replacement and infiltration of the myocardium of the right ventricle. It is suggested that death due to right ventricular cardiomyopathy seems to be the result of electrical instability of right ventricular myocardium. There were no congenital malformations such as septal defect or valvular deformity. The subjects' heart weights were normal. Signs of myocardial degeneration and necrosis with or without inflammatory infiltrates were not identified.
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A M Tsatsakis, M N Tzatzarakis, D Psaroulis, C Levkidis, M Michalodimitrakis (2001)  Evaluation of the addiction history of a dead woman after exhumation and sectional hair testing.   Am J Forensic Med Pathol 22: 1. 73-77 Mar  
Abstract: In Greece, sectional hair analysis, in addition to clinical examination, has been used as a valuable tool for the confirmation of a person's history of drug use. The present report concerns the toxicologic analysis of the exhumed remains and hair samples of an 18-year-old woman. Postmortem toxicologic analysis of blood and urine confirmed recent opiate and cannabis use and indicated that death was associated with heroin abuse. Several months later, the woman's family asked for exhumation and reexamination of the body, insisting that the cause of death was homicide. The investigating judge ordered exhumation and new medicolegal examination of the body. The investigation of the drug profile along the hair shaft was undertaken by analyzing hair sections 1 cm from the hair root for morphine, 6-monoacetylmorphine, heroin, and cannabinoids. The total lengths of the hair samples ranged from 8 to 11 cm. The total morphine levels in the hair sections corresponding to the 3-month period before death were significantly lower (1.5-2.85 ng/mg) than those of the 4- to 10-month period before death (7.4-14.8 ng/mg). An interpretation of these results may be occasional drug use (with considerable attenuation of use during the last 3 months before death). Decrease of tolerance to heroin caused by abstinence and relapse in use could have been the cause of death.
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T Mieczkowski, A M Tsatsakis, M Kruger, T Psillakis (2001)  The concentration of three anti-seizure medications in hair: the effects of hair color, controlling for dose and age.   BMC Clin Pharmacol 1: 04  
Abstract: BACKGROUND: This paper assess the relationship between the quantity of three anti-seizure medications in hair and the color of the analyzed hair, while controlling for the effects of dose, dose duration, and patient age for 140 clinical patients undergoing anti-seizure therapy. Three drugs are assessed: carbamazepine (40 patients), valproic acid (40 patients), and phenytoin (60 patients). The relationship between hair assay results, hair color, dose, dose duration, and age is modeled using an analysis of covariance. The covariance model posits the hair assay results as the dependent variable, the hair color as the qualitative categorical independent variable, and dose, dose duration, and age as covariates. The null hypothesis assessed is that there is a no relationship between hair color and the quantity of analyte determined by hair assay such that darker colored hair will demonstrate higher concentrations of analyte than lighter colored hair. RESULTS: The analysis reveals that there is a significant relationship between dose and concentration for all hair color categories independent of the other covariates or the categorical independent variable. CONCLUSION: There does not appear to be any relationship between carbamazepine concentration and hair color. There is a weak relationship between hair color and valproic acid concentration, which the data suggest may be mediated by age. There is a significant, moderate relationship between phenytoin concentration and hair color such that darker colored hair has greater concentration values than lighter colored hair.
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M Plataki, N Anatoliotakis, N Tzanakis, P Assithianakis, A M Tsatsakis, D Bouros (2001)  Availability of antidotes in hospital pharmacies in Greece.   Vet Hum Toxicol 43: 2. 103-105 Apr  
Abstract: We determined the availability of poisoning antidotes in the pharmacies of state hospitals in Greece and in Health Centers of the island of Crete. A questionnaire survey was sent to all pharmacy directors of hospitals with emergency departments, asking them to report anonymously the amount currently in stock of each of 12 common antidotes. Questionnaires were sent to 100 pharmacy directors and 68 (68%) of them replied. Only 2 (3%) of the 68 hospitals stocked all 12 antidotes. The percentage of sufficient stocking for individual antidotes ranged from 6% (for digoxin immune fab) to 91% (for methylene blue). Recent circulation of government guidelines for antidote stocking and hospital type had no significant effect on antidote stocking. In a multiple regression analysis, hospital type (prefectural, regional, university hospital) and smaller hospital size were not predictors of the number of antidotes sufficiently stocked. Storing of key poisoning antidotes is inadequate in regional as well as in prefectural hospitals in Greece. Antidotes, including those which should be used without delay to be effective, are often not available, even for the commoner poisons in Greece such as pesticides.
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G Dolapsakis, I G Vlachonikolis, C Varveris, A M Tsatsakis (2001)  Mammographic findings and occupational exposure to pesticides currently in use on Crete.   Eur J Cancer 37: 12. 1531-1536 Aug  
Abstract: This is a preliminary report of an outreach mammographic-screening programme on Crete. The screening is part of a study to test if occupational exposure to pesticides in greenhouses (mainly organophosphates and organocarbamates), may increase the risk of malignant or premalignant findings in mammographic examination. A total of 1062 women (aged 40--75 years) were recruited between 1988 and 1993 and followed-up until 1998: 522 worked for at least 10 years in greenhouses for more than 4 h daily (exposed), and 540 never worked in agriculture (non-exposed). Statistics include detection rates and relative risks of mammographic findings. 'Exposed' women had a significantly (P<0.05) higher risk than 'non-exposed' for fibroadenoma, ductal hyperplasia, sclerotic adenosis, fibrohyperplastic disease, cystic disease and inflammatory mastitis. There were no significant differences in the detection rates of fibrocystic changes, lipoma and malignant changes or malignant tumours. Compared with older women (aged 50--75 years), younger women (aged 40--49 years), particularly in the 'exposed' group, had a higher detection rate of malignant tumours. These preliminary results indicate that 'exposed' women may have higher risks of incidence for a number of lesions, which are risk markers for subsequent invasive breast cancers. They confirm also that early screening for breast cancer is effective and provides an opportunity for a reduction in breast cancer mortality.
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M N Tzatzarakis, A M Tsatsakis, E Charvalos, D Vakalounakis (2001)  Comparison of in vitro activities of amphotericin, clotrimazole, econazole, miconazole, and nystatin against Fusarium oxysporum.   J Environ Sci Health B 36: 3. 331-340 May  
Abstract: The inhibitory activity of amphotericin B, clotrimazole, econazole, miconazole and nystatin was compared against Fusarium oxysporum f.sp. radicis-cucumerinum. The most efficient antifungal agent against the growth of Fusarium oxysporum was econazole, followed by clotrimazole, miconazole, amphotericin and nystatin. The ED50 and ED90 values were 0.053 and 1.002 ppm for econazole, 0.088 and 1.100 ppm for clotrimazole, 0.173 and 3.210 ppm for miconazole, 0.713 and greater than 48 ppm for amphotericin and 3.860 and 16.702 ppm for nystatin. The ED50 values of nystatin and amphotericin against spore germination of Fusarium oxysporum were determined at 3.1427 ppm and 8.3990 ppm respectively, nystatin was 2.76 times more effective than amphotericin, while no effect was observed after the addition of econazole, clotrimazole and miconazole. The tested azoles were more effective than amphotericin and nystatin on growth inhibition of Fusarium oxysporum but amphotericin and nystatin acted significantly better on spore germination of Fusarium.
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V P Torchilin, T S Levchenko, K R Whiteman, A A Yaroslavov, A M Tsatsakis, A K Rizos, E V Michailova, M I Shtilman (2001)  Amphiphilic poly-N-vinylpyrrolidones: synthesis, properties and liposome surface modification.   Biomaterials 22: 22. 3035-3044 Nov  
Abstract: Certain amphiphilic water-soluble polymers including amphiphilic derivatives of polyvinyl pyrrolidone (PVP) were found to be efficient steric protectors for liposomes in vivo. In this study, we have tried to develop synthetic pathways for preparing amphiphilic PVP and to investigate the influence of the hydrophilic/hydrophobic blocks on some properties of resulting polymers and polymer-coated liposomes. To prepare amphiphilic PVP with the end stearyl (S) or palmityl (P) residues, amino- and carboxy-terminated PVP derivatives were first synthesized by the free-radical polymerization of vinyl pyrrolidone in the presence of amino- or carboxy-mercaptans as chain transfer agents, and then modified by interaction of amino-PVP with stearoyl chloride or palmitoyl chloride, or by dicyclohexyl carbodiimide coupling of stearylamine with carboxy-PVP. ESR-spectra of the hydrophobic spin-probe, nitroxyl radical N-oxyl-2-hexyl-2-(10-methoxycarbonyl)decyl-4,4'-dimethyl oxazoline, in the presence of amphiphilic PVP demonstrated good accessibility of terminal P- and S-groups for the interaction with other hydrophobic ligands. Spontaneous micellization and low CMC values (in a low micromolar range) were found for amphiphilic PVP derivatives using the pyrene method. In general, S-PVP forms more stable micelles than P-PVP (at similar MW, CMC values for S-PVP are lower than for P-PVP). It was found that amphiphilic PVP incorporated into negatively charged liposomes effectively prevents polycation(poly-ethylpyridinium-4-vinylchloride)-induced liposome aggregation, completely abolishing it at ca. 10 mol% polymer content in liposomes. Additionally, the liposome-incorporated PVP prevents the fluorescence quenching of the membrane-incorporated hydrophobic fluorescent label [N-(4-fluoresceinthiocarbamoyl)dipalmitoyl-PE] by the free polycation. PVP-modified liposomes were loaded with a self-quenching concentration of carboxyfluorescein, and their destabilization in the presence of mouse serum was investigated following the release of free dye. Amphiphilic PVP with MW between 1,500 and 8,000 provides good steric protection for liposomes. The degree of this protection depends on both polymer concentration and molecular size of the PVP block.
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N Papanikolaou, G Paspatis, A Dermitzakis, E Tzortzakakis, E Charalambous, A M Tsatsakis (2001)  Neutropenia induced by paraquat poisoning.   Hum Exp Toxicol 20: 11. 597-599 Nov  
Abstract: Paraquat is a synthetic, nonselective, contact herbicide, which causes injury to tissues following contact. When ingested in sufficient amounts, paraquat has life-threatening effects on the gastrointestinal tract, lungs, kidney, liver, heart and other organs. This is a case report of a 15-year-old girl from an agricultural area who was admitted to hospital for treatment. She presented with discomfort, nausea and vomiting. She had drunk a small wine glass full of paraquat. After 18 days in the hospital, the girl developed neutropenia. This is the first reported case of paraquat poisoning-induced neutropenia.
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E Charvalos, M Tzatzarakis, A Tsatsakis, G Petrikkos (2001)  Controlled release of water-soluble polymeric complexes of sorbic acid with antifungal activities.   Appl Microbiol Biotechnol 57: 5-6. 770-775 Dec  
Abstract: We synthesized six water-soluble polymeric complexes of sorbic acid with polyvinylpyrrolidone of different molecular weight (mol wt). As shown by infrared absorption spectrum analysis, the complexes were formed by hydrogen bonding. The complexes (SC1, with mol wt=10 kDa, SC2 with mol wt=25 kDa, SC3 with mol wt=30 kDa, SC4 with mol wt=40 kDa, SC5 with mol wt=90 kDa, and SC6 with mol wt=360 kDa) were characterized as low mol wt (SC1, SC2, and SC3) and high mol wt (SC4, SC5, and SC6). The antifungal potencies of the complexes were tested by the macrodilution susceptibility method against environmental and clinically important fungi. Sorbic acid as well as the complexes exhibited minimum inhibitory concentrations (MICs) lower than potassium sorbate against all the strains tested. MICs of SC1, SC2, and SC3 were shown to be 2- to 4-fold lower for yeast and 1.5- to 3-fold lower than those of sorbic acid for moulds, respectively. The MICs of SC4 and SC5 against both of the Candida species tested ranged from 500 to 800 microg/ml, whereas for SC6 and sorbic acid they were about 1 mg/ml. The potencies of the high mol wt complexes against moulds were decreased by increasing the mol wt. For both of the moulds tested, the MICs of SC4 were slightly lower than those of sorbate. The MICs of sorbic acid and SC5 were equal to 300 microg/ml and 500 microg/ml respectively for Aspergillus parasiticus and for Penicillum viridicatum. The susceptibility to SC6 of all of the hyphomycetes tested was higher than that to sorbic acid. The low mol wt complexes and the sorbic acid exhibited minimal fungicidal concentrations (MFCs) 2 and 3 times higher respectively than the MICs. Sorbic acid and SC3 at a concentration of 2.5 mg/ml in an in vitro time kill curve study of Candida tropicalis were shown to be fungistatic, whereas SC1 and SC2 were fungicidal at the same concentrations. For Aspergillus parasiticus sorbic acid at 2.5 mg/ml was fungistatic for a 24-h period, whereas SC1, SC2, and SC3 were fungicidal.
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K Psaroudakis, M N Tzatzarakis, A M Tsatsakis, M N Michalodimitrakis (2001)  The application of histochemical methods to the age evaluation of skin wounds: experimental study in rabbits.   Am J Forensic Med Pathol 22: 4. 341-345 Dec  
Abstract: Enzyme histochemical methods allow determination of wound age, especially in the range of a few hours, and are used to distinguish between postmortem and antemortem skin wounds. The methods are based on the determination of the presence and changes of the enzyme reaction in the wound area. Increased activity of nonspecific esterases was observed approximately 1 hour after wounding and was followed by an increase in adenosine triphosphatase at approximately 2 hours and alkaline phosphatase at approximately 3.5 hours. Maximum enzyme activity was reached for nonspecific esterases at 24 hours, for adenosine triphosphatase at 20 hours, and for alkaline phosphatase at 32 hours after wounding.
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2000
A M Tsatsakis, M Tutudaki, I Stiakakis, M Dimopoulou, M Tzatzarakis, M Michalodimitrakis (2000)  Characterisation of cannabis plants phenotypes from illegal cultivations in Crete.   Boll Chim Farm 139: 3. 140-145 May/Jun  
Abstract: In the present study samples of cannabis plants presented to us by the Drug Enforcement Units were characterised, based on the analysis of active substances. The fresh samples were dried in a dark room were they were kept until analysis. The samples included leaves, flowers roots and trunks. The analysis was performed by High Performance Liquid Chromatography (HPLC) and Gas Chromatography (GC) using standard solutions of cannabidiol, D-9 tetrahydrocannabinol, D-8 tetrahydrocannabinol and cannabinol. Chemical analysis of the flowers revealed that 80% of the plants were classified as resinous phenotype while the remaining 20% were found to be of the textile phenotype (low concentration of active cannabinoids). The concentration of D-9 tetrahydrocannabinol in the flowers and leaves ranged from 0.014 to 21.06 mg/g, of cannabinol from 0.0002 to 0.350 mg/g and of cannabidiol from 0.03 to 29.6 mg/g. Roots and trunks contained very small quantities of active substances and should not be used for phenotype identification. No delta-8 THC was detected in any sample. Leaves gave less resinous phenotypes than flowers. The use of either mathematical formula, A or B produced the same phenotype character for each separate part of the plant.
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I A Ramoutsaki, Y A Ramoutsakis, S Haniotakis, A M Tsatsakis (2000)  Remedies used in Hellenic history.   Vet Hum Toxicol 42: 4. 238-241 Aug  
Abstract: A large number of remedies known as "pharmaca" in Greek used for treating a disease or for other problems in medical practice have been traced back to the Hellenic period of history. Archeological data as well as literary and scientific texts suggest that the ancient Greek physicians knew how to use many remedies from herbs and plants, metals and minerals, and animals. These remedies were given per os, in liquid form (katapotia in Greek), in poultice form, or in the form of ointments and eye-drops (collyria). The main problem of ancient pharmacology was that chemistry had not yet become a science to help physicians individually distinguish each of the substances used as remedies and to estimate the exact effect they could cause to the human organism. However, especially during the classical period (Sth-4th century BC) and from the end of the Hellenic period and thereafter, remedies would be the combinations of substances presented clearly and in detail in prescriptions, giving medicine a more scientific profile of their workings.
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P E Vardas, G E Kochiadakis, N E Igoumenidis, A M Tsatsakis, E N Simantirakis, G I Chlouverakis (2000)  Amiodarone as a first-choice drug for restoring sinus rhythm in patients with atrial fibrillation: a randomized, controlled study.   Chest 117: 6. 1538-1545 Jun  
Abstract: STUDY OBJECTIVES: To investigate the efficacy and safety of amiodarone administered as the drug of first choice in the conversion of atrial fibrillation, regardless of its duration. DESIGN:: Prospective, randomized, controlled clinical study. SETTING:: Tertiary cardiac referral center. PATIENTS: Two-hundred eight consecutive patients (102 men; mean [+/- SD] age, 65 +/- 10 years) with atrial fibrillation. INTERVENTIONS: One-hundred eight patients received amiodarone, and 100 patients received placebo treatment. Patients randomized to amiodarone received 300 mg IV for 1 h, and then 20 mg/kg for 24 h. They were also given 600 mg/d orally, divided into three doses, for 1 week, and thereafter 400 mg/d for 3 weeks. Patients randomized to placebo treatment received an identical amount of saline solution IV over 24 h, and oral placebo treatment for 1 month. MEASUREMENTS AND RESULTS: Baseline clinical characteristics were similar in the two groups. Conversion to sinus rhythm was achieved in 87 of 108 patients (80.05%) who received amiodarone, and in 40 of 100 patients (40%) in the placebo group (p < 0.0001). Statistical analysis showed that the duration of the arrhythmia and the size of the left atrium affected both the likelihood of conversion to sinus rhythm and the time to conversion in both groups. No side effects requiring discontinuation of treatment were observed in either group. CONCLUSIONS: Amiodarone appears to be safe and effective in the termination of atrial fibrillation. However, extreme cases with a large left atrium and long-lasting arrhythmia need long-term therapy.
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I A Ramoutsaki, Y A Ramoutsakis, M D Tsikritzis, A M Tsatsakis (2000)  The roots of toxicology: an etymology approach.   Vet Hum Toxicol 42: 2. Apr  
Abstract: We investigated the roots of toxicology and showed the Greek origin of the word. A number of selected ancient Greek and Byzantine works show the etymology and meaning of the adjective "toxic" or "toxical" as the first composition of "toxicology". Even from early antiquity "toxic" or "toxical" have been connected with substances which cause death, a meaning which has prevailed through the ages.
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M Tzatzarakis, A M Tsatsakis, A Liakou, D J Vakalounakis (2000)  Effect of common food preservatives on mycelial growth and spore germination of Fusarium oxysporum.   J Environ Sci Health B 35: 4. 527-537 Jul  
Abstract: The growth and spore germination inhibition of Fusarium oxysporum f.sp. radicis-cucumerinum by the common food additives: acetic acid, formic acid potassium sorbate, propionic acid, sorbic acid, and the fungistatic agent sec-butylamine was examined in vitro. The inhibitory efficacy of these chemicals decreased in the following order: sorbic acid, potassium sorbate, propionic acid, acetic acid, sec-butylamine and formic acid. At pH 6.4, the ED50 value for mycelium growth was: 976 ppm for sorbic acid, 1292 ppm for potassium sorbate, 2435 ppm for propionic acid, 3805 ppm for acetic acid, 3962 ppm for sec butylamine and 4668 ppm for formic acid. The ED50 value for spore germination was: 225 ppm for potassium sorbate, 1201 ppm for sorbic acid, 1402 ppm for propionic acid, 1600 ppm for sec-butylamine, 1957 ppm for acetic acid and 2485 ppm for formic acid.
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A K Alegakis, M N Tzatzarakis, A M Tsatsakis, I G Vlachonikolis, V Liakou (2000)  In vitro study of oxytetracycline adsorption on activated charcoal.   J Environ Sci Health B 35: 5. 559-569 Sep  
Abstract: In vitro adsorption experiments simulating pH in gastric environment and using Langmuir isotherm, showed that 408 mg of oxytetracycline was adsorbed per gram of activated charcoal. Langmuir isotherm fitted adsorption data better than a Freundlich isotherm. Freundlich isotherm showed a specific adsorption capacity of 518 mg/g for activated charcoal. Both isotherm parameters indicated a strong oxytetracycline adsorption on activated charcoal in terms of quantity and binding strength. The results demonstrate that the concomitant use of oxytetracyline and activated charcoal should be avoided.
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M N Tzatzarakis, A M Tsatsakis, M M Lotter, M I Shtilman, D J Vakalounakis (2000)  Effect of novel water-soluble polymeric forms of sorbic acid against Fusarium oxysporum f.sp. radicis-cucumerinum.   Food Addit Contam 17: 12. 965-971 Dec  
Abstract: New controlled release water-soluble formulations of sorbic (2,4-hexadienoic) acid were prepared and their inhibitory activity on mycelium growth of Fusarium oxysporum f.sp. radicis-cucumerinum was evaluated. The new products are epoxidized polymers of polyvinylpyrrolidone (PVP) containing covalently bonded sorbic acid (polymeric esters of sorbic acid) and complexes of PVP with hydrogen bonded sorbic acid, characterized by controlled release of sorbic acid. It was shown that the polymeric complexes of sorbic acid with PVP were more effective fungicidal agents than sorbic acid polymeric esters. In all cases the activity of polymeric derivatives (esters and complexes) was increased by lowering the molecular weight of the polymeric carriers. Controlled release formulations of these polymeric derivatives are new promising products due to their low toxicity, wide range of efficient concentrations for application and ability to regulate lyophilicity. Our data contribute to the understanding of the action mechanism of various polymeric sorbic acid formulations and can result in products which are particularly suitable for food and feed protection applications.
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I A Ramoutsaki, S Haniotakis, A M Tsatsakis (2000)  The snake as the symbol of medicine, toxicology and toxinology.   Vet Hum Toxicol 42: 5. 306-308 Oct  
Abstract: We investigated the meaning and the roots of the snake's usage as a symbol of medicine, the medical profession, toxicology and toxinology by examining mythological, archeological data and a variety of texts from the ancient Greek world. The snake figure was associated with Asclepios, the ancient Greek God of medicine, and possessed benevolent properties. It was believed to be able to cure a patient or a wounded person just by touch. The snake is also connected with pharmacology and antisepsis, as snakes possess an antivenom against their own poison. The snake is related to sciences associated with poison and death, such as toxicology and toxinology, and it also implies a metaphysical idea. It is connected with the underworld, not only because it crawls on the ground, but because it can bring death, connecting the upper with the underground world. The ability of the snake to shed its skin has been associated with the circle of life, and the renaissance spirit also, ever since early Hellenic antiquity. Consequently, as a symbol of the modern medical profession, toxicology and toxinology, the snake twisted around a stick or the snake beside a pharmapeutic cup, which also implies the use of medicines or even poison, has its roots in the ancient Mediterranean area as proven by the archeological data combined with literary references. Its benevolent as well as its poisonous properties could be paralleled by the similar properties of medicines.
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A M Tsatsakis, T Psillakis, N Paritsis (2000)  Phenytoin concentration in head hair sections: a method to evaluate the history of drug use.   J Clin Psychopharmacol 20: 5. 560-573 Oct  
Abstract: Phenytoin (PHT) levels were determined in sections of head hair taken from 60 patients (34 males and 26 females), aged 5 to 69 years, who were regularly receiving the drug. The hair sectional analysis included dissolution, liquid phase extraction procedures, and immunoassay (Abbott TDx) or high-pressure liquid chromatography (HPLC) analytical techniques. The values of PHT levels in the hair from the first section (close to the hair root) to the fifth section for female patients were 18.0, 15.2, 13.1, 11.6, and 10.7 microg/g, respectively, according to HPLC measurements. There were no significantly different results obtained using the immunoassay technique, according to which the mean values of PHT in the hair sections were 17.9, 15.2, 13.1, 11.9, and 10.9 microg/g, respectively, from the first to the fifth sections. The corresponding mean values for male patients by HPLC and immunoassay techniques, respectively, were 17.9, 15.0, 12.5, 12.1, and 12.3 microg/g and 17.8, 14.9, 12.2, 11.9, and 121 microg/g. Generally, a reduction of drug concentrations in hair from the first to the subsequent segments was observed. The hair PHT concentrations were found to be dependent on the dosage (by fluorescence polarization immunoassay: r = 0.987, p < or = 0.02; by HPLC: r = 0.988, p < or = 0.02). Mean dose and assay outcome values by hair color and correlation between hair PHT mean values, daily mean doses of the drug, and patients' age are presented. The differences among doses according to hair color were significant. PHT hair profiles from female and male patients compared with the mean +/- SD concentrations of the hair sections are discussed. The data indicate the possible use of hair section testing as a marker of the dosage history and the compliance of patients receiving long-term treatment with PHT.
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1999
H Kokori, C H Giannakopoulou, E Hatzidaki, S Athanaselis, A Tsatsakis, S Sbyrakis (1999)  An unusual case of lead poisoning in an infant: nursing-associated plumbism.   J Lab Clin Med 134: 5. 522-525 Nov  
Abstract: Lead poisoning remains a common environmental threat for children today. The majority of cases of lead poisoning are caused by oral intake of lead dust or lead-containing paint flakes and thus occur during the second and third years of life. An unusual case of severe lead poisoning in a breast-feeding infant girl is here presented; the source proved to be a nipple shield made of a lead-containing metal. Despite the severity of the intoxication, by the end of treatment and for a year afterwards the infant has been well and her psychokinetic development has been normal.
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M Michalodimitrakis, P Christodoulou, A M Tsatsakis, I Askoxilakis, I Stiakakis, I Mouzas (1999)  Death related to midazolam overdose during endoscopic retrograde cholangiopancreatography.   Am J Forensic Med Pathol 20: 1. 93-97 Mar  
Abstract: We report a midazolam-related death that occurred during endoscopic retrograde cholangiopancreatography (ERCP). The acute intoxication due to midazolam overdose was confirmed by high-pressure liquid chromatography (HPLC) analysis of the blood samples taken from the patient in the intensive care unit (2.8 microg/ml) and postmortem (2.4 microg/ml). The case strongly emphasizes the necessity of the precautions that should be taken when midazolam is intravenously administered.
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I Petrakis, C Gonianakis, N Vrachassotakis, A Tsatsakis, I S Vallilakis, G Chalkiadakis (1999)  Prospective study of preincisional intraparietal single-dose ceftriaxone in reducing postoperative wound infection in type I and II diabetic patients.   Acta Diabetol 36: 3. 159-162 Sep  
Abstract: The risk of wound contamination in diabetic patients after abdominal operations is well known. Preincisional intraparietal injection of antibiotics is used for the prophylaxis of postoperative surgical infections. Whether topically injected antibiotics remain primarily in the surgical wound or are systematically absorbed is uncertain, however. The pharmacokinetics of a preincisional, intraparietal injection of 2 g ceftriaxone was studied in 50 consecutive diabetic (type I and II) patients undergoing abdominal surgery, with determination of serum, wound tissue, and wound fluid antibiotic concentrations. Preincisional intraparietal injection of ceftriaxone resulted in high antibiotic concentrations in the wound fluid. The highest plasma concentrations were achieved at 1.5 h (98.45 microg/ml, SD = 14.54). Plasma concentrations exceeded the minimal inhibitory concentrations of most aerobic gram positive and gram negative organisms with the exception of Pseudomonas aeruginosa, Acinetobacter species, and Streptococcus faecalis for 24 h (10.35 microg/ml, SD = 4.10). No long-lasting or general complications arose in any of the diabetic patients. Our results suggest that preincisional intraparietal administration of ceftriaxone for prophylaxis of wound sepsis in diabetic patients with high risk of infection is effective.
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A K Alegakis, A M Tsatsakis, M I Shtilman, D L Lysovenko, I G Vlachonikolis (1999)  Deactivation of mycotoxins. I. An in vitro study of zearalenone adsorption on new polymeric adsorbents.   J Environ Sci Health B 34: 4. 633-644 Jul  
Abstract: This study describes the elimination of zearalenone concentrations in vitro using two new polymeric forms of cross-linked polyvinylpyrrolidone (cryogels of cross-linked PVP). Adsorption of zearalenone was studied under isothermal conditions and simulating pH of intestinal environment. A Freundlich isotherm was used to describe the adsorption data obtained. The results showed significant decrease of zearalenone concentrations, ranging from 33.5-66.2% per 25 mg of polymer. Adsorption capacity (k) was estimated to be higher than that of previously tested adsorbents, including crospovidone. The data indicate the need to investigate structure peculiarities in order to improve mycotoxin deactivation procedures using PVP derivatives.
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K Relakis, S Sifakis, G Froudarakis, E Papadopoulou, E N Michalodimitrakis, E Koumantakis, A Tsatsakis (1999)  Disposition of pesticides and toxicants in the human reproductive system in cases of acute poisoning.   Clin Exp Obstet Gynecol 26: 3-4. 207-210  
Abstract: The aim of this study was to estimate the penetration of some of the pesticides and toxicant substances in the human reproductive system. This knowledge is valuable because of the possible adverse influence of these substances on the human reproduction system and the development of the foetus during pregnancy. The existing data is mainly concerned with the results of experimental studies on animals or epidemiological studies. Here we report data concerning the disposition of several toxic xenobiotics (pesticides and solvents) in the tissues of the human reproductive system as well as in other organs and glands. Data was collected from cases of acute poisonings and derived mostly from autopsy materials. Xenobiotics were found to penetrate sampled tissues such as the testes, ovaries, epididymis, uterus, thyroid gland, as well as other human tissues. Further studies will clarify and confirm peculiarities of the penetration of a wide range of substances in various body tissues and will be the base of the estimation of the role of these toxicants in human reproductive ability and the outcome of pregnancy in humans.
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T Psillakis, A M Tsatsakis, P Christodoulou, M Michalodimitrakis, N Paritsis, E Helidonis (1999)  Carbamazepine levels in head hair of patients under long-term treatment: a method to evaluate the history of drug use.   J Clin Pharmacol 39: 1. 55-67 Jan  
Abstract: Carbamazepine (CBZ) concentrations were determined in the sections of head hair from 40 patients (22 males and 18 females), ages 5 to 81, who were receiving this drug systemically. Hair treatment included dissolution, liquid phase extraction procedures, and immunoassay (Abbott TDx) or high-pressure liquid chromatography (HPLC) analytical techniques. The mean values of CBZ levels in the hair from the 1st section (close to hair root) to the 5th section for female patients were 26.82, 19.18, 17.28, 15.09, and 14.62 micrograms/g according to HPLC measurements. Immunoassay gave generally slightly higher results. The mean values of CBZ in the hair sections according to the immunoassay technique were 30.53, 21.90, 19.83, 17.45, and 16.99 micrograms/g, respectively, from the 1st to the 5th sections. The corresponding mean values for male patients by HPLC and immunoassay techniques were 21.97, 17.30, 15.03, 13.02, and 11.21 micrograms/g and 25.98, 20.52, 17.15, 14.87, and 12.31 micrograms/g. Generally, a reduction of drug concentrations in hair from the first to the subsequent segments was observed. Higher amounts of CBZ were deposited in black, untreated hair (e.g., not dyed or permed). CBZ concentrations in hair sections were found to be dependent on the dosage (r = 0.979, p < or = 0.001) but not on the gender. The data indicate the possible use of hair section testing as a marker of the dosage history and the compliance of patients under long-term treatment with CBZ.
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1998
A M Tsatsakis, A Manousakis, M Anastasaki, M Tzatzarakis, K Katsanoulas, C Delaki, P Agouridakis (1998)  Clinical and toxicological data in fenthion and omethoate acute poisoning.   J Environ Sci Health B 33: 6. 657-670 Nov  
Abstract: This study paper reports on two cases of poisoning with the organophosphorus insecticides, fenthion and omethoate. The two victims were admitted in the Intensive Care Unit (ICU) a few hours after ingestion of the two insecticides. They received appropriate treatment for organophosphorous poisoning (gastric lavage, activated charcoal, atropine and pralidoxime) and supportive care. Both patients survived. Organophosphate blood levels were determined on admission (fenthion 2.9 micrograms/ml, omethoate 1.6 micrograms/ml) and during the hospitalisation and proved to be considerably high. Slow elimination rate of the poison already distributed in the body was indicated for both pesticides. The patient with omethoate poisoning remained clinically well (Glasgow Coma Scale: 15) and was discharged three days later. The patient with fenthion poisoning, who had also ingested 30 mg of bromazepam and 720 mg of oxetoron, developed cholinergic crisis six hours after admission and was intubated for 24 days, with concomitant complications.
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M Michalodimitrakis, A Tsatsakis (1998)  Massive pulmonary embolism by liver tissue.   Med Sci Law 38: 1. 85-87 Jan  
Abstract: An unusual accidental death due to acute massive occlusion of the right pulmonary arteries by liver tissue is reported. A 17-year-old motorcyclist was run over by a heavy truck, resulting in multiple injuries. Multiple lacerations of the liver and tears in the wall of the inferior vena cava resulted in the complete occlusion of the right pulmonary artery by liver tissue. Although the victim sustained other potentially lethal injuries, the final mechanism of death is attributed to pulmonary embolism.
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A M Tsatsakis, M I Tutudaki, M N Tzatzarakis, K Psaroudakis, G P Dolapsakis, M N Michalodimitrakis (1998)  Pesticide deposition in hair: preliminary results of a model study of methomyl incorporation into rabbit hair.   Vet Hum Toxicol 40: 4. 200-203 Aug  
Abstract: This work studied the incorporation of methomyl, a carbamate insecticide, into the hair of New Zealand white rabbits. A total of 600 mg methomyl was administered by drinking water over 4 mo, and acetylcholinesterase activity in serum was monitored. At the end of the dosing period, hair from the back of the rabbits was cut off, and the methomyl concentration was measured using ELISA and HPLC. A decrease of serum acetylcholinesterase occurred. The top cm of hair contained no methomyl, the second cm contained 0.9 ng/mg and the 3rd cm of hair contained 3 ng methomyl/mg. Methomyl was incorporated into the rabbit hair in a process independent of gender but dependent on the hair growth rate.
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M Christakis-Hampsas, M Tutudakis, A M Tsatsakis, P Assithianakis, A Alegakis, P G Katonis, E N Michalodimitrakis (1998)  Acute poisonings and sudden deaths in Crete: a five-year review (1991-1996).   Vet Hum Toxicol 40: 4. 228-230 Aug  
Abstract: Fatal and non-fatal acute poisonings and other sudden deaths examined in the Toxicology Laboratory of University Hospital of Iraklion, Crete, from 1991 to 1996 mainly involved the abuse of drugs (heroin, flunitrazepam and other psychoactive substances), accidental poisonings or suicide attempts with pesticides (carbamates, organophosphates, paraquat), other chemicals (cyanide salts, paint thinner, chlorine), traffic accidents, drownings and violent deaths (gunshots). Many of the cases were related to poisonous gases or volatiles (carbon monoxide, methylbromide). Fatalities due to alcohol and methylene-dioxy-ethyl amphetamine were also examined. Amphetamine and alcohol-related deaths due to drowning were more recent. A significant number of cases were related to the accidental ingestion of alcohol, drugs or suicide attempts by children. Some of the cases were treated successfully in various Cretan hospitals, while others had fatal outcomes due to late hospital admission.
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G E Kochiadakis, N E Igoumenidis, M C Solomou, F I Parthenakis, M G Christakis-Hampsas, G I Chlouverakis, A M Tsatsakis, P E Vardas (1998)  Conversion of atrial fibrillation to sinus rhythm using acute intravenous procainamide infusion.   Cardiovasc Drugs Ther 12: 1. 75-81 Mar  
Abstract: The efficacy and safety of intravenous procainamide in the conversion of atrial fibrillation was investigated. A total of 114 patients without severe heart failure were randomized to receive either intravenous procainamide (1 g over 30 minutes, followed by an infusion of 2 mg/min over 1 hour) or placebo in a double-blind trial. Digoxin (0.5 mg intravenously) was administered to all patients who had not previously been receiving digoxin. Treatment was considered successful if sinus rhythm was restored within 1 hour after starting the infusion. Conversion to sinus rhythm was achieved in 29 (50.9%) of the 57 patients treated with procainamide and in 16 (28.1%) of the 57 who received placebo (P approximately 0.012). When the duration of the atrial fibrillation was < or = 48 hours, conversion to sinus rhythm was achieved in 29 (69%) of the 42 patients receiving procainamide and in 16 (38.1%) of those receiving placebo (P approximately 0.004). None of the patients with atrial fibrillation lasting > or = 48 hours converted to sinus rhythm in either group. Another factor that played a role in the restoration of sinus rhythm was the size of the left atrium: the smaller the left atrium, the larger the success rate. The results of the study suggest that intravenous procainamide is an effective and safe means for the rapid termination of atrial fibrillation of recent onset and that its success rate is inversely related to the size of the left atrium. However, the drug is ineffective in the conversion of atrial fibrillation lasting more than 48 hours.
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A M Tsatsakis, T Psillakis, A Stefis, P Assithianakis, I G Vlahonikolis, M N Michalodimitrakis, E Helidonis (1998)  Determination of phenytoin in sections of head hair: a preliminary study to evaluate the history of drug use.   Boll Chim Farm 137: 11. 459-466 Dec  
Abstract: Phenytoin (PH) levels were determined in the head hair of twenty five patients (fourteen males and eleven females, aged from five to seventy seven years old) who were receiving this drug chronically. The assay method involved sectional hair analysis by dissolution and liquid phase extraction procedures, using both high pressure liquid chromatography (HPLC) and immunoassay (Abbott TDx) techniques. Five sections were studied, the first being the one closet to the root. The phenytoin levels of the hair sections ranged: a) 1st: 0.68 to 39.56 micrograms/g (mean 16.12 micrograms/g), b) 2nd: 0.85 to 34.15 micrograms/g (mean 9.45 micrograms/g), c) 3rd: 1.33 to 27.90 micrograms/g (mean 3.72 micrograms/g), d) 4th: 1.10 to 10.96 micrograms/g (mean 3.04 micrograms/g) and e) 5th: 1.05 to 7.00 micrograms/g (mean 2.84 micrograms/g) according to the HPLC analysis. The immunoassay technique gave similar results. The mean values of phenytoin in the hair sections according to the immunoassay technique were: 16.28; 9.47; 3.77; 3.22; 2.97 micrograms/g, respectively from the 1st to the 5th section. A reduction of drug concentrations in hair from the first to the consecutive segments was observed. Higher amounts of phenytoin were deposited in black, untreated hair in comparison to blond brown or grey hair. Phenytoin concentrations in hair sections correlated with the oral daily dosage of the drug. Our data indicate to the use of hair testing as a marker of the dosage history and evaluation of the compliance of patients under long treatment with phenytoin.
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A M Tsatsakis (1998)  Judicial applications of hair testing for addicts in Crete: sectional hair analysis of heavy heroin abusers.   J Clin Forensic Med 5: 3. 109-113 Sep  
Abstract: Laboratory examination of hair from drug users has been employed for the last 5 years in Crete, in addition to the psychiatric or other forensic clinical examinations necessary for the confirmation of a person's use of drugs. The present study reports results of total and sectional head, axillary and pubic hair analysis of imprisoned abusers under interrogation and awaiting presentation at the Crime Court. Morphine levels in total head hair samples 1, 2 and 4 months after preliminary imprisonment ranged from 1.2 to 38.2, 0.5 to 22.5 and 0.1 to 4.9 ng/mg of hair respectively, while the maximum morphine levels amongst all studied groups of those arrested were found in the sections of axillary and pubic hair. Notably high morphine levels in head, axillary and pubic hair sections (13.7, 8.4 and 18.1) ng/mg respectively) were measured, even in abusers who had been imprisoned between 2 and 4 months. Hair tests may considerably assist to evaluate the systematic present and past abuse of heroin and other drugs. Consequently, it may be used as valuable expertise evidence during questioning and in court.
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I Petrakis, N Vrachassotakis, A Tsatsakis, G Chalkiadakis (1998)  Prospective study of preincisional single-dose ceftriaxone in reducing postoperative wound infection in high risk of infection patients.   Eur Rev Med Pharmacol Sci 2: 3-4. 141-145 May/Aug  
Abstract: BACKGROUND-AIMS: The risk of wound contamination in high risk of infection patients after abdominal operations is well recognised. Preincisional intraparietal injection of antibiotics is used for the prophylaxis of postoperative surgical infections. Whether topically injected antibiotics remain primarily in the surgical wound or are systematically absorbed is uncertain, however. PATIENTS AND METHODS: The pharmacokinetic of preincisional injection of 2 g Ceftriaxone were studied in 50 high risk of infection patients (diabetic, oncologic, immunocompromised and obese) who have undergone abdominal surgery, with determination of serum, wound tissue, and wound fluid antibiotic concentrations. RESULTS: Preincisional injection of Ceftriaxone resulted in high antibiotic concentrations in the wound fluid. The highest plasma concentrations were achieved at 1 1/2 hours (98.30 SD 14.10 micrograms/ml). Plasma concentrations exceeded the minimal inhibitory concentrations of most aerobic gram positive and gram negative organisms with the exception of Pseudomonas aeruginosa, Acinobacter species, and Streptococcus faecalis for 24 hours (10.10 SD 4.00 micrograms/ml). No longer of general complications were arose in any of the patients. CONCLUSION: Our results suggest that preincisional administration of ceftriaxone for prophylaxis of the wound sepsis in high risk of infection patients is very effective.
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1997
G Troulakis, A M Tsatsakis, M Tzatzarakis, A Astrakianakis, G Dolapsakis, R Kostas (1997)  Acute intoxication and recovery following massive turpentine ingestion: clinical and toxicological data.   Vet Hum Toxicol 39: 3. 155-157 Jun  
Abstract: Reports of acute turpentine intoxication, particularly containing toxicological data, are poorly verified in the literature. This report regards the intentional massive ingestion of turpentine solution in an elderly woman who developed mainly central nervous system manifestations, then had an impressive and quick total recovery although the initial prognosis was very bad. Blood and urine levels of turpentine were monitored using gas chromatography and at the early toxicogenic stage were 28 micrograms/mL and 15 micrograms/mL respectively. Gastric fluid analysis on admission to the hospital revealed the presence of approximately 200 mL turpentine in the intestine. A review of earlier reports is given.
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A M Tsatsakis, T K Psillakis, M Tzatzarakis, H Kourtopoulos, N Paritsis (1997)  Carbamazepine levels in the hair of patients under long-term treatment: a preliminary study.   Clin Chim Acta 263: 2. 187-195 Jul  
Abstract: Carbamazepine (CBZ) levels in the scalp hair of seventeen patients (ten male and seven female), aged from five to forty years old, receiving the drug systematically were determined after hair dissolution and solid-phase extraction procedures using both immunoassay (Abbott TDx) and gas chromatographic (GC) techniques. Carbamazepine levels in hair ranged from 13.9 to 66.3 micrograms/g (mean 26.6 micrograms/g, median 20.9 micrograms/g) according to GC measurements. The immunoassay technique gave slightly higher results (mean 28.0 micrograms/g, median 22.1 micrograms/g). The blood concentrations of carbamazepine, using immunoassay (Abbott TDx) technique, ranged from 2.9 to 10.7 micrograms/ml (mean 6.2 micrograms/ml, median 5.7 micrograms/ml). Our data indicate the possible use of hair testing as a marker of the dosage history of patients under long-term treatment with CBZ.
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M N Michalodimitrakis, A M Tsatsakis, M G Christakis-Hampsas, N Trikilis, P Christodoulou (1997)  Death following intentional methyl bromide poisoning: toxicological data and literature review.   Vet Hum Toxicol 39: 1. 30-34 Feb  
Abstract: A case of fatal poisoning due to ingestion-inhalation of methyl bromide (MeBr) is presented. In previously reported fatalities due to MeBr inhalation, only inorganic bromide levels in biological specimens were reported. Intact MeBr has not been isolated from human tissues following exposure. In the present case, MeBr was detected, confirmed and quantitated in various biological samples by headspace gas chromatography, and the clinical manifestations and autopsy findings are described. Postmortem MeBr peripheral blood concentration was 3.3 micrograms/mL and in subclavian blood was 3.8 micrograms/mL. Lung, brain, adrenal gland, kidney, liver and testis MeBr was 2.9, 3.5, 3.4, 2.6, 1.9 and 2.8 micrograms/g respectively; MeBr in bile was 1.2 micrograms/mL. Inorganic bromide concentrations were 530, 30, 310 and 130 micrograms/g in blood, brain, kidney and adrenal gland respectively.
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M N Michalodimitrakis, R La Grange, A M Tsatsakis (1997)  Suicide by alcohol overdose.   J Clin Forensic Med 4: 2. 91-94 Jun  
Abstract: Alcohol is the most often detected substance in the body of a person who has committed suicide. It may be used to reduce the last instinctive hestitations to taking one's own life. Suicide is common in cancer patients. People with cancer-related depression often use alcohol as a means of coping but they very rarely use it in order to kill themselves through acute intoxication. However, a case of a cancer patient who committed suicide consuming two bottles of spirit was recently investigated and the conclusions are presented. The post-mortem cardiac blood and vitreous humor alcohol level was found to be 9.0 and 6.2 mg/ml respectively.
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A M Tsatsakis, M N Michalodimitrakis, A N Patsalis (1997)  MDEA related death in Crete: a case report and literature review.   Vet Hum Toxicol 39: 4. 241-244 Aug  
Abstract: "Designer drugs" are derivatives of approved drugs abused for recreational effect and created by underground laboratories to circumvent legal restriction. By far the most controversial drug has been MDMA (3,4-methylenedioxymethamphetamine) and the newer derivative MDEA (3,4-methylenedioxymethamphetamine) often called "Eve". MDEA-related deaths have not been reported in the US, but there have been a death of MDMA and MDEA severe poisonings. Convulsions, collapse, hyperpyrexia, disseminated intravascular coagulation rhabdomyolysis, and acute liver and renal damage result from the ingestion of the drug. Complications may occur and severity and death possibly result. The case of a 31-y-old male, the first victim of MDEA in Greece, is reported. Blood MDEA was 3.1 micrograms/mL; MDEA concentrations in liver, lung and kidney were 4.8, 5.2, and 4.8 micrograms/g respectively.
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A M Tsatsakis, G Dolapsakis, G Troulakis, P Christodoulou, K Relakis, N Trikilis, M N Michalodimitrakis (1997)  Fatal and non-fatal outcome by accidental intoxication with paint thinner.   J Clin Forensic Med 4: 3. 133-137 Sep  
Abstract: Although poisonings (fatal and non-fatal) due to intentional or accidental acute exposure to toluene or toluene mixture fumes have been previously reported in the literature, several issues concerning lethal doses or lasting post-exposure neuropathological impairments still remain unclear. Two male painters (18 and 30 years old) were accidentally exposed to toxic concentrations of paint diluent fumes containing toluene (TL), acetone (ACT) and methyl ethyl ketone (MEK) (60:15:15 w/w/w respectively) during their work in an underground reservoir. Both workers were found unresponsive by colleagues and were immediately transferred to the regional hospital. On admission, the younger man was pronounced dead, while the other remained in the intensive care unit for 3 days and then 4 days in the internal medicine ward. TL, ACT and MEK concentrations in blood samples taken from the survivor on admission were 6.3, 30.6 and 40.5 microg/mL. Postmortem toxicology of the dead worker revealed TL, ACT and MEK blood levels of 12.4, 90.8 and 80.4 microg/mL respectively. The solvent levels in the liver, kidney, lung, brain, testis and gland were also quantified and showed a somewhat similar distribution of the chemicals among these tissues with the highest levels found in the brain and the liver. The fatal and the non-fatal outcome that resulted despite similar intoxication conditions, most probably demonstrates the interindividual tolerance among the painters who also had similar body weights. The surviving painter did not develop any neuropsychological impairment in post-exposure time. The reported case strongly emphasizes the necessity to take precautions when using paint diluents in enclosed spaces.
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M Michalodimitrakis, A Tsatsakis (1997)  The changing status of forensic medicine in Greece.   J Clin Forensic Med 4: 4. 159-162 Dec  
Abstract: The practice of forensic medicine in Greece is similar to that in other European countries. That is Greece follows the continental model of sudden death investigations, whose norms govern the exercise of forensic medicine through Greek criminal procedure law. In Greece, a university and Government system of forensic medicine exist and occasionally work side-by-side. University departments are strategically placed in all districts of the country. State forensic medicine services are located in Athens, Piraeus and Crete and function in parallel with the local University departments of forensic medicine. Forensic examinations on the living are also exclusively performed by the University and State Legal Medicine services. The cases are simply divided according to the countries of these areas. A recent regulation by the Supreme Court eliminated the overlapping of jurisdictions emphasizing the role of the University departments, and finally establishing a new University-oriented medico-legal system throughout Greece.
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E N Michalodimitrakis, A M Tsatsakis (1997)  Vehicular accidents and cardiac concussion. A traumatic connection.   Am J Forensic Med Pathol 18: 3. 282-284 Sep  
Abstract: Concussion of the heart (commotio cordis) occurs in traffic accidents in which blunt force impact over the precordial area occurs, even in the absence of multiple blunt force injuries. The functional dynamics of the heart, with ventricular arrythmias and conduction disturbances, serve as the pathophysiological basis of this condition. As a cause of death in vehicular accidents, it is less common than other causes. However, it should be considered in the differential diagnosis, especially in cases with minor or no apparent injuries.
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1996
A M Tsatsakis, A K Tsakalof, Y Siatitsas, E N Michalodimitrakis (1996)  Acute poisoning with carbamate pesticides: the Cretan experience.   Sci Justice 36: 1. 35-39 Jan/Mar  
Abstract: In Crete, in southern Greece, a number of fatal carbamate poisonings were investigated over a period of 2 years, from 1991 to 1993. Five cases are reported, involving the fatal ingestion of methomyl (Lannate), a cholinesterase-inhibiting carbamate insecticide. Analysis of samples of blood plasma and serum showed more than 90% inhibition of cholinesterase. The blood methomyl concentrations had a mean value of 26.7 mg/l, and a range of 5.6-57.0 mg/l. These values are much higher than those previously reporter in similar cases (0.57-1.4 mg/l). Methomyl concentrations in organs and tissues were found to be significantly lower than those in blood and vitreous humour.
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A M Tsatsakis, A K Tsakalof, E N Michalodimitrakis (1996)  The analysis of methomyl, a carbamate pesticide, in post-mortem samples.   Sci Justice 36: 1. 41-45 Jan/Mar  
Abstract: Extraction procedures and analytical methods are described for the quantitation of methomyl, a carbamate insecticide, in autopsy tissue and fluid samples. The analytical results from case work demonstrate the rapid metabolism of methomyl in the body.
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A M Tsatsakis, K Perakis, E Koumantakis (1996)  Experience with acute paraquat poisoning in Crete.   Vet Hum Toxicol 38: 2. 113-117 Apr  
Abstract: Ten cases of acute paraquat poisonings with lethal (n = 5) and non-lethal (n = 5) outcomes are presented. Paraquat plasma and urine levels of the patients on admission (from 2 to 41 h after ingestion) at the peripheral hospitals varied from 0.4 to 6.0 and 0.5 to 12.8 micrograms/ml, respectively. Besides standard supportive treatment, hemoperfusion/hemodialysis and/or plasmapheresis were performed for therapy, which in 1 case lasted for 28 d. The pharmacokinetic data from patient paraquat elimination confirmed considerable paraquat rebound from tissues to blood circulation and marked the need for continued therapy even with undetectable paraquat plasma levels. Postmortem analysis showed that while paraquat was mainly distributed in kidney (807 micrograms/g), lung (479 micrograms/g) and liver (206 micrograms/g), amounts were also detected in thyroid (64 micrograms/g), testis (21 micrograms/g), vitreous humor (45 micrograms/ml) and cerebrospinal fluid (7.4 micrograms/ml). Paraquat crossed the placenta and concentrated there to higher levels than in the mother's blood. The fetus seemed to tolerate the mother's paraquat intoxication while dependent on placental circulation.
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A M Tsatsakis, P Aguridakis, M N Michalodimitrakis, A K Tsakalov, A K Alegakis, E Koumantakis, G Troulakis (1996)  Experiences with acute organophosphate poisonings in Crete.   Vet Hum Toxicol 38: 2. 101-107 Apr  
Abstract: Nine human acute poisonings due to intentional ingestion of organophosphorous pesticides are presented. Six of the victims died. Six patients were treated in the Intensive Care Unit (ICU) from 34 h to 45 d, while 3 were found dead by relatives. Two of the patients treated in the ICU fully recovered after 15 and 24 d while the third survivor developed delayed neuropathy. Organophosphate blood levels were determined on admission and during therapy, and in 1 case atropine and pralidoxime levels were also detected. Significant fluctuations of the plasma cholinesterase activity were observed during therapy. Postmortem analysis revealed higher levels of pesticides in organs (eg 23.1 micrograms fenthion/g kidney) and in fat (135.2 micrograms fenthion/g) than in blood (eg 4.8 micrograms fenthion/ml) and vitreous humor. Considerable pesticide was measured in testis (eg 5.8 micrograms fenthion/g, 0.8 micrograms methidathion/g) and uterus (170.5 micrograms malathion/g). Extracorporeal decontamination to enhance pesticide elimination is a therapeutic challenge.
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1995
D Bouros, P Agouridakis, A Tsatsakis, E Askitopoulou, N M Siafakas (1995)  Orthodeoxia and platypnoea after acute organophosphorus poisoning reversed by CPAP: a newly described cause and review of the literature.   Respir Med 89: 9. 625-628 Oct  
Abstract: The case of a 60-year-old male patient, who survived severe organophosphorus poisoning, and subsequently developed platypnoea and orthodeoxia is described. The patient was mechanically ventilated for a long period of time in the intensive care unit. During the weaning trial, he developed platypnoea and orthodeoxia (PaO2 85 mmHg in recumbency, and 40 mmHg in upright position). Interestingly, the patient's orthodeoxia was alleviated on continuous positive airway pressure (CPAP) treatment. This is a newly described cause of the platypnoea-orthodeoxia syndrome. The possible pathophysiological mechanisms are discussed and a review of the reported abnormal states associated with this condition is presented.
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G E Chalkiadakis, C Gonnianakis, A Tsatsakis, A Tsakalof, M Michalodimitrakis (1995)  Preincisional single-dose ceftriaxone for the prophylaxis of surgical wound infection.   Am J Surg 170: 4. 353-355 Oct  
Abstract: BACKGROUND: Preincisional intraparietal injection of antibiotics is used for the prophylaxis of postoperative surgical infections. Whether topically injected antibiotics remain primarily in the surgical wound or are systematically absorbed is uncertain, however. PATIENTS AND METHODS: The pharmacokinetics of preincisional injection of 2 g ceftriaxone were studied in 20 patients who have undergone abdominal surgery, with determination of serum, wound tissue, and wound fluid antibiotic concentrations. RESULTS: Preincisional injection of ceftriaxone resulted in high antibiotic concentrations in the wound tissue and wound fluid. The highest plasma concentrations were achieved at 1.50 hours (99.47 +/- 14.67 micrograms/mL). Plasma concentrations exceeded the minimal inhibitory concentrations of most aerobic gram-positive and gram-negative organisms with the exception of Pseudomonas aeruginosa, Acinetobacter species, and Streptococcus faecalis for 24 hours (10.42 +/- 4.12). No local or general complications arose in any of the patients. CONCLUSIONS: Our results suggest that preincisional administration of ceftriaxone for prophylaxis is very effective.
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