Abstract: Impaired fetal development has been linked with deficits in behavioural and emotional development during postnatal life. In order to investigate the mechanisms underlying this relationship, we studied the effect of acute stress at two different critical phases of pregnancy on cognitive function in adult guinea pig offspring. Pregnant guinea pigs were exposed to a psychological stressor (2h/day) on gestational days (gd) 50, 51, and 52 (PS50) or 60, 61, and 62 (PS60). Male offspring were grown to adulthood and tested in the Morris water maze (MWM) to assess spatial learning and memory. Latency, path length, swim speed and the strategy used to find the platform in each session of the MWM were measured. A reverse learning trial was performed where the platform was moved to a different area of the pool and the ability of the guinea pigs to learn a new platform position was assessed. There was no effect of stress at gd50 on latency to find the platform during any of the sessions in the MWM. PS60 male offspring exhibited enhanced development of a spatial strategy during sessions 3 and 4 of the MWM, but this was not associated with decreased latency. In the reversal task PS50 male offspring demonstrated use of non-spatial strategies to find the platform during the reversal task. This would suggest decreased retention of spatial memory in these animals. In contrast, control and PS60 male offspring demonstrated no bias to a particular strategy type. In conclusion, there are subtle effects of prenatal stress on spatial learning. PS60 offspring appear to exhibit enhanced spatial learning, while PS50 male offspring exhibit impaired spatial learning. These findings are consistent with those in humans, which indicate a strong effect of maternal anxiety during pregnancy on cognition in children, and that the timing of the maternal stress is critical to determining outcome. This model will allow us to determine the mechanisms that underlie the association between prenatal stress and altered learning strategy and ability.
Abstract: BACKGROUND: Analysis of hospital mortality helps to assess the standards of health-care delivery. METHODS: This is a retrospective cohort study evaluating the causes of deaths which occurred during the years 1995-1999 in a single hospital. The causes of death were classified according to the International Statistical Classification of Diseases (ICD-10). RESULTS: Of the 149,896 patients who were discharged the 5836 (3.4%) died. Males constituted 55% and females 45%. The median age was 75.1 years (1 day - 100 years). The seven most common ICD-10 chapters IX, II, IV, XI, XX, X, XIV included 92% of the total 5836 deaths. The most common contributors of non-neoplasmatic causes of death were cerebrovascular diseases (I60-I69) at 15.8%, ischemic heart disease (I20-I25) at 10.3%, cardiac failure (I50.0-I50.9) at 7.9%, diseases of the digestive system (K00-K93) at 6.7%, diabetes mellitus (E10-E14) at 6.6%, external causes of morbidity and mortality (V01-Y98) at 6.2%, renal failure (N17-N19) at 4.5%, influenza and pneumonia (J10-J18) at 4.1% and certain infectious and parasitic diseases (A00-B99) at 3.2%, accounting for 65.3% of the total 5836 deaths. Neoplasms (C00-D48) caused 17.7% (n = 1027) of the total 5836 deaths, with leading forms being the malignant neoplasms of bronchus and lung (C34) at 3.5% and the malignant neoplasms of large intestine (C18-21.2) at 1.5%. The highest death rates occurred in the intensive care unit (23.3%), general medicine (10.7%), cardiology (6.5%) and nephrology (5.5%). Key problems related to certification of death were identified. Nearly half of the deaths (49.3%: n = 2879) occurred by the completion of the third day, which indicates the time limits for investigation and treatment. On the other hand, 6% (n = 356) died between the 29th and 262nd days after admission. Inadequacies of the emergency care service, infection control, medical oncology, rehabilitation, chronic and terminal care facilities, as well as lack of regional targets for reducing mortality related to diabetes, recruitment of organ donors, provision for the aging population and lack of prevention programs were substantiated. CONCLUSION: Several important issues were raised. Disease specific characteristics, as well as functional and infrastructural inadequacies were identified and provided evidence for defining priorities and strategies for improving the standards of care. Effective transformation can promise better prospects.
Abstract: Maternal stress during pregnancy, particularly that combined with low socioeconomic status (SES), has been linked to an increased risk for impaired behavioural and emotional development and affective disorders in children. In animal models, acute periods of prenatal stress have profound effects on hypothalamo-pituitary-adrenal (HPA) function and behaviour. However, few studies have determined the impact of chronic exposure to stress in animal models. The objective of this study was to determine the effects of chronic maternal stress (CMS) during the 2nd half of pregnancy and nursing on growth, locomotor behaviour and HPA axis function in juvenile guinea pig offspring. Pregnant guinea pigs were exposed to a random combination of variable stressors every other day over the 2nd half of gestation and from postnatal day (pnd) 1 until weaning (pnd25). CMS mothers displayed increased basal salivary cortisol levels in the later stages of pregnancy compared to control mothers (p<0.05). The male offspring of CMS mothers had a lower bodyweight, which was maintained to weaning (p<0.01). In open-field testing, CMS male offspring showed a decrease in activity compared to controls (p<0.05). There was no effect of CMS on bodyweight or activity in female offspring. In contrast, both male and female offspring born to CMS mothers displayed increased (p<0.05) basal salivary cortisol at pnd25, but a blunted adrenocortical response to exposure to the novel open-field enclosure. In conclusion, CMS leads to modification of growth trajectory, locomotor activity and adrenocortical responses to stress in juvenile offspring. Further, males appear considerably more vulnerable to these effects than females.
Abstract: Prenatal stress (PS) and maternal exposure to exogenous glucocorticoids can lead to permanent modification of hypothalamo-pituitary-adrenal (HPA) function and stress-related behaviour. Both of these manipulations lead to increased fetal exposure to glucocorticoids. Glucocorticoids are essential for many aspects of normal brain development, but exposure of the fetal brain to an excess of glucocorticoids can have life-long effects on neuroendocrine function. Both endogenous glucocorticoid and synthetic glucocorticoid exposure have a number of rapid effects in the fetal brain, including modification of neurotransmitter systems and transcriptional machinery. Such fetal exposure permanently alters HPA function in prepubertal, postpubertal and ageing offspring, in a sex-dependent manner. Prenatal stress and exogenous glucocorticoid manipulation also lead to the modification of behaviour, brain and organ morphology, as well as altered regulation of other endocrine systems. It is also becoming increasingly apparent that the timing of exposure to PS or synthetic glucocorticoids has tremendous effects on the nature of the phenotypic outcome. Permanent changes in endocrine function will ultimately impact on health in both human and animal populations.
Abstract: BACKGROUND: For early melanoma diagnosis, experienced dermatologists have an accuracy of 64-80% using clinical diagnostic criteria, usually the ABCD rule, while automated melanoma diagnosis systems are still considered to be experimental and serve as adjuncts to the naked-eye expert prediction. In an attempt to aid in early melanoma diagnosis, we developed an image processing program with the aim to discriminate melanoma from melanocytic nevi, establishing a mathematical model to come up with a melanoma probability. METHODS: Digital images of 132 melanocytic skin lesions (23 melanomas and 109 melanocytic nevi) were studied in features of geometry, color, and color texture. A total of 43 variables were studied for all lesions, e.g., geometry, color texture, sharpness of border, and color variables. Univariate logistic regression analysis followed by "-2 log likelihood" test and Spearman's rank correlation coefficient were used to eliminate inappropriate variables, as the presence of multi-collinearity among variables could cause severe problems in any stepwise variable selection method. Initially, "-2 log likelihood" and nonparametric Spearman's rho picked five variables to be included in a multivariate model of prediction. The five-variable model was then reduced to three variables and the performance of each model was tested. The "jackknife" method was performed in order to validate the model with the three variables and its accuracy was weighed vs. the five-variable model by receiver-operating characteristics (ROC) curve plotting. It was concluded that the reduced model did not compromise discriminatory power. RESULTS: Not all variables contributed much to the model, therefore they were progressively eliminated and the model was finally reduced to three covariates of significance. A predictive equation was calculated, incorporating parameters of geometry, color, and color texture as independent covariates for the prediction of melanoma. The proposed model provides melanoma probability with a 60.9% sensitivity and 95.4% specificity of prediction, an overall accuracy of 89.4% (probability level 0.5), and 8% false-negative results. CONCLUSIONS: Through a digital image processing system and the development of a mathematical model of prediction, discrimination between melanomas and melanocytic nevi seems feasible with a high rate of accuracy using multivariate logistic regression analysis. The proposed model is an alternative method to aid in early melanoma diagnosis. Expensive and sophisticated equipment is not required and it can be easily implemented in a reasonably priced portable programmable computer, in order to predict previously undiagnosed skin melanoma before histopathology results confirm diagnosis.
Abstract: The multidrug resistance phosphoglycoprotein ATP-binding cassette subfamily B (ABCB1) actively extrudes a range of structurally and functionally diverse xenobiotics as well as glucocorticoids. ABCB1 is present in many cancer cell types as well as in normal tissues. Although it has been localized within the mouse placenta, virtually nothing is known about its regulation. In the mouse, two genes, Abcb1a and Abcb1b, encode ABCB1. We hypothesized that there are changes in placental Abcb1a and Abcb1b gene expression and ABCB1 protein levels during pregnancy. Using in situ hybridization, we demonstrated that Abcb1b mRNA is the predominant placental isoform and that there are profound gestational changes in the expression of both Abcb1a and Abcb1b mRNA. Placentas from pregnant mice were analyzed between Embryonic Days (E) 9.5 and 19 (term approximately 19.5d). Abcb1b mRNA was detected in invading trophoblast cells by E9.5, peaked within the placental labyrinth at E12.5, and then progressively decreased toward term (P < 0.0001). Abcb1a mRNA, although lower than that of Abcb1b at midgestation, paralleled changes in Abcb1b mRNA. Changes in Abcb1 mRNA were reflected by a significant decrease in ABCB1 protein (P < 0.05). A strong correlation existed between placental Abcb1b mRNA and maternal progesterone concentrations, indicating a potential role of progesterone in regulation of placental Abcb1b mRNA. In conclusion, there are dramatic decreases in Abcb1a and Abcb1b mRNA and in ABCB1 at the maternal-fetal interface over the second half of gestation, suggesting that the fetus may become increasingly susceptible to the influences of xenobiotics and natural steroids in the maternal circulation.
Abstract: Fetal exposure to excess glucocorticoids (GCs) programs the developing hypothalamo-pituitary-adrenal (HPA) axis, and may predispose offspring to adult-onset disease. During development, serotonin (5-HT) influences transcription of hippocampal GR mRNA via the 5-HT7 receptor. The effect of 5-HT on GR involves the transcription factor NGFI-A. Given the developmental changes which we have previously reported in hippocampal GR mRNA expression, we hypothesized that (1) there are progressive developmental changes in 5-HT7 receptor and NGFI-A mRNA expression in the fetal guinea-pig limbic system, and (2) repeated exposure to synthetic GC treatment will significantly modify developmental expression of these genes. 5-HT7 receptor mRNA was highly expressed in the hippocampus and thalamus at gestational day (gd) 40 (term approximately 70 days), and significantly decreased (P < 0.05) with advancing gestation. Conversely, NGFI-A mRNA expression in the hippocampus and frontal cortex was almost undetectable at gd40, but was dramatically elevated (P < 0.05; 8-fold) near term. Changes in mRNA were refelected by NGFI-A protein levels. These changes were significantly correlated to hippocampal GR expression and fetal plasma cortisol concentrations. Synthetic GC treatment increased NGFI-A mRNA levels in CA1 and the cingulate cortex, but had no effect on 5-HT7 receptor expression. In conclusion our results suggest that (1) limbic 5-HT7 receptor expression is not directly linked to maturation of hippocampal GR in late gestation; (2) the up-regulation of NGFI-A expression near term is driven by glucocorticoid; and (3) premature exposure to synthetic glucocorticoid significantly increases NGFI-A-related transcriptional activity in the fetal limbic system.
Abstract: Steroid receptor coactivator (SRC) proteins interact with glucocorticoid receptors in a ligand-dependent manner to enhance transcription. Although glucocorticoids are essential for normal brain maturation, little is known about the presence or regulation of SRC proteins in the developing central nervous system. In the current study we demonstrated that SRC-1 was highly expressed in the fetal limbic system (hippocampal CA3>CA1/2>CA4>dentate gyrus) at gestational d (gd) 40 (term, approximately 70 d), whereas SRC-2 was undetectable at all time points. Hippocampal SRC-1 mRNA and protein expression were reduced in male and female fetuses with advancing gestation. In contrast, SRC-1 mRNA levels increased significantly in the dentate gyrus near term. Repeated maternal injection (1 or 10 mg/kg on gd 40, 41, 50, 51, 60, and 61) with synthetic glucocorticoid had no effect on fetal limbic SRC-1 expression at gd 62 in either sex. SRC-1 and SRC-2 mRNA expression in the anterior pituitary did not change over the second half of gestation and was unaffected by prenatal exposure to synthetic glucocorticoid. In conclusion, SRC-1 expression undergoes spatial, temporal, and region-specific regulation during development, and limbic and pituitary SRC-1 and SRC-2 are not regulated by glucocorticoids in late gestation. Developmental changes in limbic SRC-1 expression probably have important consequences on steroid receptor signaling, which is known to be critical for brain maturation in late gestation.
Abstract: The developmental changes in 5-HT1A receptor mRNA expression associated with advancing gestational age were examined in the fetal guinea pig hippocampus and dentate gyrus (DG) by in situ hybridization. We found that 5-HT1A receptor mRNA was present in the hippocampal CA1 subfield and dentate gyrus (DG), and was significantly (P < 0.05) elevated in the DG during the period of rapid brain growth [gestational day (gd) 50; term = 70 days]. Glucocorticoids have been shown to alter 5-HT1A receptor mRNA expression in the adult, but nothing is known about their impact on the developing fetal brain. Expression of 5-HT1A receptor mRNA in the fetal hippocampus was measured following repeated maternal administration (gd40, 41, 50, 51, 60 and 61) of synthetic glucocorticoid (dexamethasone; 1 and 10 mg/kg). Levels of 5-HT1A receptor mRNA were significantly (P < 0.005) elevated in CA1 and DG following repeated exposure to high-dose glucocorticoid (10 mg/kg) in male, but not in female fetuses. Because fetal exposure to glucocorticoids programs hypothalamo-pituitary-adrenal (HPA) function, and hippocampal serotonin is known to influence glucocorticoid receptor (GR) expression, the glucocorticoid-mediated changes in 5-HT1A receptor mRNA may play a role in the programming of HPA function.
Abstract: A histological study of both recipient and flap vessels was performed in 30 patients with head and neck cancer, and relevant preoperative risk factors were assessed. A total of 35 free flaps were transferred in 30 patients; 16 patients had preoperative radiotherapy, 13 were smokers, eight had hypertension and six had peripheral vascular disease. No significant venous pathology was found in either the flap or the neck veins. However, over two-thirds of the neck arteries and one-half of the flap arteries were found to have microscopic arterial pathology. The only pre-existing factor significantly influencing vessel pathology was hypertension (P=0.007). All flaps survived, although in two there was some loss of the skin paddle. This study reveals that the majority of patients undergoing microsurgery in the head and neck region have pre-existing arterial damage in both the flap and the recipient arteries, but this does not have a significant effect on the overall patency of the microvascular anastomoses.
