Short-term effects of continuous positive airway pressure on oxidative stress in severe sleep apnea

Sleep and Breathing - Obstructive sleep apnea (OSA) is associated with oxidative stress that is involved in the pathogenesis of cardiovascular and metabolic complications. The concentrations of...     

Effects of testosterone and estradiol on anxiety and depressive-like behavior via a non-genomic pathway

Besides their known slow genomic effects, testosterone and estradiol have rapid effects in the brain. However, their impact on mood-related behavior is not clear. The aim of this study was to investigate the non-genomic pathway of testosterone and estradiol in the amygdala in relation to anxiety and depressive-like behavior. Sham-operated and gonadectomized male rats(GDX) supplemented with testosterone propionate, estradiol, or olive oil were used. Five minutes after administration, anxiety and depression-like behavior were tested. Estradiol increased anxiolytic behavior in the open-field test compared to the GDX group, but administration of testosterone had no significant effect. Besides, c-Fos expression in the medial nucleus of the amygdala significantly increased after testosterone treatment compared to the GDX group, while no significant difference was observed in the central and the basolateral nuclei of the amygdala in the testosterone-treated group compared to the GDX group. In conclusion, estradiol had an anxiolytic effect via a rapid pathway, but no rapid effect of testosterone on anxiety was found. Further studies elucidating whether the rapid effect is mediated by a non-genomic pathway are needed.     

Short‐term effects of continuous positive airway pressure on sex hormones in men and women with sleep apnoea syndrome

Patients with sleep apnoea syndrome (SAS) suffer from symptoms of hypogonadism. Besides surgical interventions, in some cases, the standard care of SAS for most patients is continuous positive airway pressure (CPAP). Studies focusing on the long‐term effects of CPAP on testosterone levels revealed conflicting results. None of the studies included female patients with SAS. The aim of our study was to analyse and compare sex hormone levels in saliva before and after a night without and with CPAP in women and men with SAS. The results were negative. One night with CPAP did not affect the dynamics of sex hormones, neither in men nor in women. Future studies should focus on long‐term effects of CPAP in both genders.     

Physical activity induces depression-like behavior in intact male rats

Testosterone affects behavior. Whether regular physical training does influence these effects is unknown. The assumption that testosterone induces muscular hypertrophy if combined with physical training has not been confirmed experimentally. The aim of this study was to evaluate whether activity and/or testosterone treatment affects depression-like behavior and to observe the effects of activity and testosterone on muscle fiber diameter.Forty-three male rats were divided into 4 groups: two groups (TST act and TST lazy) were treated with testosterone (5 mg/kg) and two groups were used as control (CTRL act and CTRL lazy). Two of the groups (CTRL act and TST act) underwent 2 weeks of exercise. The forced swim test was used as a test of depression-like behavior. Sex steroids were measured and the diameter of skeletal muscle fibers was evaluated.Testosterone was significantly higher in both testosterone-treated groups (p < 0.001). Physically active groups had higher immobility times in the forced swim test than inactive groups. Groups CTRL act and TST lazy showed significantly larger diameter of muscle fibers in comparison to the TST act group.Our results suggest that physical activity induces depression-like behavior in rats. Controversial antagonistic effects of testosterone and physical activity on muscle fiber diameter were found.     

Increased one week soybean consumption affects spatial abilities but not sex hormone status in men

BACKGROUND: Increased soybean intake is often recommended for the prevention of hormone-dependent cancer, cardiovascular diseases and age-related cognitive decline. Although isolated phytoestrogens have shown these positive effects, the evidence for such influence of increased consumption of soybeans is lacking. AIM: To prove the effects of short-term increased soybean intake on sex hormone levels and spatial cognitive parameters in men. SUBJECTS AND METHODS: Seven young healthy men were asked to eat 900 g soybeans during 1 week. Sex hormone levels were determined in saliva and plasma, and mental rotation and spatial visualization were quantified by standard psychometric tests. All parameters were assessed before and after the study. RESULTS: Plasma estradiol, total and free testosterone, as well as salivary testosterone and estradiol remained unchained. Spatial cognitive performance was improved after increased soybean intake when considering spatial visualization (P=0.03). The results for mental rotation showed similar dynamics, but the changes were not significant. CONCLUSION: Short-term increased soybean intake does not affect sex hormone status, but improves spatial cognitive performance in young healthy men.     

Salivary thiobarbituric acid reacting substances and malondialdehyde--their relationship to reported smoking and to parodontal status described by the papillary bleeding index

Background. Thiobarbituric reacting substances (TBARS) are markers of lipoperoxidation. The best-known specific TBARS is malondialdehyde (MDA). Results from our previous studies have shown that TBARS can be measured in saliva and are increased in patients with gingivitis. Whether MDA is the main TBARS in saliva from patients with altered parodontal status is unknown. Aim. To observe the relationship between the parodontal status and TBARS, MDA and the number of epithelial cells in saliva. Subjects & Methods. In Study I saliva and plasma samples of 15 patients (8F, 7M) suffering from inflammatory periodontal diseases were gathered and TBARS levels were measured in these samples. In Study II saliva samples from 217 consecutive stomatologic patients were collected and analysed for TBARS spectrofluorometrically, MDA by high-performance liquid chromatography and epithelial cell count by light microscopy. Papillary bleeding index (PBI) was determined in standard stomatologic examination. Results. In Study I results from our previous studies showing no correlation between salivary and plasma TBARS levels were confirmed. This indicates that the local salivary level of TBARS is unlikely to be directly affected by systemic oxidative stress. In Study II higher PBI was associated independently (adjusted for age and sex) tightly with higher TBARS (p < 0.001) and with lower number of epithelial cells in saliva (p < 0.05). Smokers had higher salivary MDA levels (p < 0.003) and lower number of epithelial cells in saliva (p < 0.01). Conclusion. Salivary TBARS are a simple parameter that partially reflects the parodontal status with a potential usefulness in the clinical stomatology. We show herein that salivary MDA is dependent on age and smoking, but there is no correlation between MDA and PBI. Further studies should uncover the main salivary TBARS compound in patients with altered parodontal status and trace the origin of these salivary lipoperoxidation markers.     

Student scientific activity at the Bratislava medical faculty 2000–2004. A scientometric study

Students at the Bratislava medical faculty interested in research can participate voluntarily in a student scientific activity (SSA). Currently, the scientific activity is measured by the quantity and quality of publications and these scientometric parameters are important for grant evaluations as well as for individual careers. In this study, we evaluate the publication successes of SSA papers presented at the SSA conference (SSAC) of Faculty of medicine in Bratislava during the last five years. Names of the first authors of works presented at the SSAC in 2000–2004 were searched in PubMed/Medline and in Thomson ISI Web of Science/Current Contents (CC) in January 2005. Only titles of full text publications (not abstracts) similar to those presented at the SSAC were counted and further analyzed. Publication points were counted according to the currently valid PhD credit system at the Faculty of Natural Sciences, Comenius University, Bratislava. A total of 141 students scientific activity works were presented during a five-year period, with a total of 4 domestic non-CC, 11 foreign non-CC and 9 foreign CC publications, with cumulative impact factor 10,6 and total publication points of 641,2. Publication points gradually increased during the years 2000–2003. In conclusion, medical student research activity can significantly influence the publication output of our medical faculty and should, thus, be further supported. The SSA will probably gain even more importance after the introduction of a mandatory diploma thesis, moreover, if we take into account the increasing significance of evaluations based on scientometric parameters.     

The age-dependent effect of pre-pubertal castration on anxiety-like behaviour in male rats

Adolescence is considered to be a critical period of sex hormone action (re)organising the brain and determining the behavioural phenotype. Such organisational effects in the brain might be the cause of sex differences in some behavioural features. In this experiment, we aimed to examine the role of pubertal sex hormones in development of anxiety in male rats. Male rats underwent gonadectomy prior to puberty onset, and were tested for explorative and anxiety-like behaviour in adolescence as well as in young adulthood. In adolescence, but not in adulthood, gonadectomised rats spend by 50% more time (p < .05) in the centre zone of the open-field than sham-operated counterparts. Young adult gonadectomised rats showed approximately 1.5-fold greater exploratory activity, in both open field (p < .001) and elevated plus maze (p < .01), in comparison with young adult control rats. Our results indicate that pre-pubertal castration may have test-specific anxiolytic effect in adolescent male rats, and it may attenuate the decline in explorative behaviour in young adult males. These differences in short- and long-term effects of gonadectomy could explain some contradictory results of previous studies on the role of testosterone in anxiety-like behaviour of male rodents. Thus, the age-specific consequences of pre-pubertal hormone deprivation should be considered.