Orhan Bas

Effects of prenatal exposure to a 900 MHz electromagnetic field on the dentate gyrus of rats: a stereological and histopathological study.

Electromagnetic fields (EMFs) inhibit the formation and differentiation of neural stem cells during embryonic development. In this study, the effects of prenatal exposure to EMF on the number of granule cells in the dentate gyrus of 4-week-old rats were investigated. This experiment used a control (Cont) group and an EMF exposed (EMF) group (three pregnant rats each group). The EMF group consisted of six offspring (n=6) of pregnant rats that were exposed to an EMF of up to 900 megahertz (MHz) for 60 min/day between the first and last days of gestation. The control group consisted of five offspring (n=5) of pregnant rats that were not treated at all. The offspring were sacrificed when they were 4 weeks old. The numbers of granule cells in the dentate gyrus were analyzed using the optical fractionator technique. The results showed that prenatal EMF exposure caused a decrease in the number of granule cells in the dentate gyrus of the rats (P<0.01). This suggests that prenatal exposure to a 900 MHz EMF affects the development of the dentate gyrus granule cells in the rat hippocampus. Cell loss might be caused by an inhibition of granule cell neurogenesis in the dentate gyrus.

The protective effect of fish n-3 fatty acids on cerebral ischemia in rat hippocampus

Reactive oxygen species (ROS) have been implicated in the pathogenesis of cerebral injury after ischemia-reperfusion (I/R). Fish n-3 essential fatty acids (EFA), contain eicosapentaenoic acids (EPA) and docosahexoenoic acids (DHA), exhibit antioxidant properties. DHA is an important component of brain membrane phospholipids and is necessary for the continuity of neuronal functions. EPA prevents platelet aggregation and inhibits the conversion of arachidonic acid into thromboxane A(2) and prostaglandins. They have been suggested to be protective agents against neurological and neuropsychiatric disorders. In this study, the neuroprotective effects of fish n-3 EFA on oxidant-antioxidant systems and number of apoptotic neurons of the hippocampal formation (HF) subjected to cerebral I/R injury was investigated in Sprague-Dawley rats. Six rats were used as control (Group I). Cerebral ischemia was produced by occlusion of both the common carotid arteries combined with hypotension for 45 min, followed by reperfusion for 30 min, in rats either on a standard diet (Group II) or a standard diet plus fish n-3 EFA (Marincap((R)), 0.4 g/kg/day, by gavage) for 14 days (Group III). At the end of procedures, the rats were sacrificed and their brains were removed immediately. The levels of malonedialdehyde (MDA) and nitric oxide (NO) and activities of superoxide dismutase (SOD) and catalase (CAT) were measured in left HF. In addition, the number of apoptotic neurons was counted by terminal transferase dUTP nick end labelling (TUNEL) assay in histological samples of the right HF. We found that SOD activities and MDA levels increased in Group III rats compared with Group II rats. On the other hand, CAT activities and NO levels were found to be decreased in Group III rats compared with Group II rats. Additionally, the number of apoptotic neurons was lower in Group III in comparison with Group II rats. The present findings suggest that fish n-3 EFA could decrease the oxidative status and apoptotic changes in ischemic rat hippocampal formation. Dietary supplementation of n-3 EFA may be beneficial to preserve or ameliorate ischemic cerebral vascular disease.

Comparison of Three Methods for the Estimation of Total Intracranial Volume Stereologic, Planimetric, and Anthropometric Approaches

There is a well-known close relationship between the total intracranial volume (TIV) and the brain size. Several studies in different countries have estimated the cranial capacity, which indirectly reflects the brain volume. However, we have not seen a study evaluating the results of the methodologies for the assessment of TIV. This study was carried out on 30 normal subjects whose ages ranged between 19 and 77 years old (males, 18; females, 12). Three different methods were used to assess the TIV. The mean (±SD) estimated TIV using linear dimensions method in males and females were 1416.8 ± 64 cm3 and 1291.9 ± 152 cm3, respectively. The mean estimated TIV using point counting method in males and females was 1474 ± 93 cm3 and 1252 ± 72 cm3, respectively. By using the planimetric method of the mean and SD of TIV, male and females were 1492.1 ± 74 cm3 and 1319.6 ± 100 cm3, respectively. There were no statistical difference between TIV measurements obtained using the optimized stereologic technique and planimetry (P > 0.05). TIV between males and females was statistically significant (P < 0.001). This study showed that there are minor differences among the given 3 distinct methods. With the disadvantage of requiring more time to apply, the planimetry and point counting methods provide more assumption-free results than the anthropometric approach. However, the anthropometric method can be applied to assess TIV without needing sophisticated tools.

Effects of formaldehyde exposure on granule cell number and volume of dentate gyrus: a histopathological and stereological study.

The hippocampal formation is a complex region of the brain related to memory and learning. The purpose of the present study was to determine whether exposure of neonatal rats to formaldehyde (FA) had either early or delayed effects on the numbers of granule cells in the dentate gyrus (DG). After birth, the neonatal male Wistar rats were exposed throughout a 30-day period to various concentrations of FA: 0 (control group), 6 ppm (low concentration group) and 12 ppm (high concentration group). This was done by placing them for 6 h/day and 5 days per week in a glass chamber containing FA vapor. Then, five animals from each group were anesthetized and decapitated on postnatal day (PND) 30, and the remaining five animals were sacrificed on PND 90 by intracardiac perfusion using 10% neutral buffered FA solution. The Cavalieri principle of stereological approaches was used to determine the volume of the DG in these sections. The optical fractionator counting method was used to estimate the total number of granule cells in the DG. The appearance of granule cells was normal under light microscopy in all PND 30 and PND 90 groups. There were significant age-related reductions in the volume of the DG at PND 90 irrespective of which group was examined. Significant age-related neuron loss was also determined at PND 90 compared to that at PND 30. Rats treated with a high concentration FA were found to have fewer granule cells than either the animals treated with a low concentration FA or the control group (p<0.01 and p<0.01, respectively) at PND 90 but not at PND 30. These findings clearly indicate that granule cells in the DG may be vulnerable to stress and the concentration of FA to which they are exposed during early postnatal life, and also that a neurotoxic effect of high dose FA on cell number is only seen after a long time period. These results may explain why some disorders do not appear until later life.

Effect of prenatal exposure to an anti-inflammatory drug on neuron number in cornu ammonis and dentate gyrus of the rat hippocampus: A stereological study

Prenatal exposed to an anti-inflammatory drug is a major problem for the developing central nervous system. It is not well known the effect of prenatal exposed to a non-steroidal anti-inflammatory drug on the hippocampus. Total neuron number in one side of the cornu ammonis (CA) and gyrus dentatus (GD) of the hippocampal formation in control and drug-treated (diclofenac sodium, DS) groups of male rats was estimated using the optical fractionator technique. Each main group has also two subgroups that are 4 weeks old (4W-old) and 20 weeks old (20W-old). In CA, no significant difference between 4W-old DS-treated and their control was found, but a significant difference was observed between 20W-old DS-treated and their controls. A decreasing of neuron number was 12% for 20W-old DS-treated group. In GD, a decreasing of the granule cell number in 4W-old of DS-treated group was seen but an increasing of granule cell number was found in the 20W-old drug-treated rats in comparison to its control group, 7% and 9%, respectively. Although an increasing of neuron number in CA at the control group was seen with age, from 4th week to 20th week (10%), age-dependent substantial granule cell decline (17%) was observed in GD. No age effect on the total cell numbers of CA and GD of the drug-treated groups was seen in comparison to 4W-old week and 20W-old. A pronounced neuron loss observed in the drug-treated group may be attributed to the neurotoxicity of diclofenac sodium (DS) on the developing hippocampal formation. Age-dependent neuron increase in the CA of 20W-old and neuron decline in GD of 20W-old control groups may be a result of a dual effect of saline injection during the fetal life, since these animals were exposed to a stress of 15-day-period of saline injection, prenatal stress. The reason of no age effect on CA and GD cell number in the drug-treated groups may be attributed to the depletion of the progenitor cells due to neurotoxicity of DS in the fetal life of these animals.

Variations in the intracranial vertebrobasilar system

AimThe aim of our study was to demonstrate some possible variations in the vertebrobasilar system (VBS) in the Turkish population and to compare our results with the literature.Materials and methodsThe VBS samples were taken from 109 fresh forensic autopsies and one anatomic cadaver. The widths of the vertebral artery (VA), the basilar artery (BA) and their branches were measured; dominancy and hypoplastic arteries, as well as the types of variations and their locations, were determined.ResultsHypoplastic VA was observed at rates of 20.2% on the right, 14.4% on the left and 4.8% bilaterally. The vertebrobasilar junction was found to be either at the level of bulbopontine sulcus (20%), below the sulcus (67%) or above the sulcus (12%). BA variations were observed as duplications of the proximal (0.9%) and distal segments (1.8%). Anterior spinal artery (ASA) originated as a single trunk in 12.5% of the cases. ASA arose from a transverse anastomosis connecting VAs in 6.3% of the cases. Furthermore, 15.6% of ASAs were double. The observed variations in the superior cerebellar artery were early bifurcation (7.2% on the right, 12.7% on the left), fenestration (4.5% on the right, 7.2% on the left), duplication (14.5% on the right, 12.7% on the left) and origin as a common trunk (6.3% on the right, 10% on the left).ConclusionOur results show that a high percentage of variations can be seen even in a small number of cases. We believe that our data are clinically important because, for example, variations are a factor which increases the incidence of aneurism and thrombus. We also think our results will contribute to the demography of our country and to clinical medicine.

Body fat composition and distribution in women with polycystic ovary syndrome.

Objectives. The aims of the present study were to compare the distribution and accumulation of body fat in women with polycystic ovary syndrome (PCOS) and healthy controls matched for age and body mass index (BMI), and to investigate the association between androgen levels, insulin resistance and fat distribution. Materials and methods. Thirty-one PCOS women and 29 age- and BMI-matched healthy control women were evaluated in terms of subcutaneous adipose tissue thickness determined with a skinfold caliper and body composition analyzed by bioelectrical impedance analysis. Blood samples were obtained for determination of follicle-stimulating hormone, luteinizing hormone, 17β-estradiol, 17-hydroxyprogesterone, basal prolactin, testosterone, dehydroepiandrosterone sulfate, sex hormone-binding globulin (SHBG), androstenedione, insulin and glucose levels. Insulin sensitivity was estimated by fasting glucose/insulin ratio and free androgen index (FAI) was calculated as 100 × testosterone/SHBG. Differences between means were analyzed by Students t test or the Mann–Whitney U test according to distribution of the data. Correlation analysis was performed between the body fat distribution and parameters concerning insulin resistance and androgens. Results. FAI was significantly higher in patients with PCOS compared with the control group (p = 0.001). Fasting insulin was significantly higher and fasting glucose/insulin ratio was significantly lower in the PCOS group vs. controls (p = 0.03 and 0.001, respectively). There was significantly less subcutaneous adipose tissue in the controls than the PCOS women at the triceps (p = 0.04) and subscapular region (p = 0.04). Waist-to-hip ratio of PCOS women was significantly higher than that of control subjects (p = 0.04). Conclusion. Upper-half type body fat distribution is linked with PCOS, high free testosterone levels and insulin resistance.

Effects of postnatal formaldehyde exposure on pyramidal cell number, volume of cell layer in hippocampus and hemisphere in the rat : A stereological study

The purpose of the present study was to determine whether exposure of neonatal rats to formaldehyde (FA) had either early or delayed effects on the numbers of pyramidal cells in the cornu ammonis (CA) of the hippocampus. Neonatal Wistar rats were exposed to 0 ppm (control group), 6 ppm and 12 ppm (high concentration group) of FA concentrations throughout the 30-day period following the birth by placing them for 6 h/day in a glass chamber containing FA vapor. Then, some of the animals from each FA-treated group were anesthetized and decapitated at the day 30, and the remaining ones were killed at the day 90. The brains were removed immediately and fixed in 10% neutral-buffered FA solution. The Cavalieri principle was used to determine the volumes of the CA and the entire cerebral hemisphere. The optical fractionator counting method was used to estimate the total number of pyramidal cells in the CA. The appearance of pyramidal cells was normal under light microscopy at both postnatal day (PND) 30 and PND 90 in all groups. There were concentration-related volume changes of CA at PND 30 and PND 90; low concentration of FA significantly increased, whereas high concentration decreased the volume of CA in comparison of the control at PND 30. Importantly, high concentration of FA at PND 90 increased the volume of CA in comparison of the low concentration but not with the control. Furthermore, low and high concentrations of FA decreased the volume of hemisphere at PND 30, whereas a reverse effect of these concentrations was observed at the hemisphere of PND 90 in comparison of the control. In both CA and cerebral hemisphere, an age-related volume decrease in both control and low/high concentration groups were found. On the other hand, there were significant age-related reductions in the total number of pyramidal cells at 90 days of age irrespective of the groups examined. Rats treated with high concentration FA were seen to have significantly fewer pyramidal cell neurons than either the animals treated with low concentration FA or control groups (p<0.01). These observations indicate that pyramidal cells in the hippocampus may be vulnerable to FA exposure during the early period of life.

Novel approach for the prevention of contrast nephropathy

OBJECTIVE To date, there is no effective treatment of contrast medium (CM)-induced nephropathy. Multiple studies documented a protective role of hydration and N-acetylcystein (NAC) as prophylactic agents against CM-induced nephropathy in a high-risk population. In the present study, we investigated a new antioxidant agent, caffeic acid phenethyl ester (CAPE), and compare with NAC against contrast nephropathy. METHODS Forty-two adult male rats were divided into six experimental groups, which were control, injected with intravenous (i.v.) CM, injected with i.p. CAPE, injected with i.p. NAC, injected with i.v. CM pretreated with i.p. CAPE, injected with i.v. CM pretreated with i.p. NAC. CAPE and NAC were given daily throughout the study. All rats were deprived of water for 24h at the third day of the study and then contrast medium was administered to CM, CAPECM and NACCM groups. The rats were sacrificed at the fifth day. Oxidant-antioxidant status was determined in renal tissues. The severity of injury was scored with a light microscope in renal tissue. Plasma creatinine levels were measured. RESULTS Renal injury scores were higher in CAPECM and NACCM groups than in control, CAPE and NAC groups, but lower than the CM group. Likewise, creatinine levels of CAPECM and NACCM groups were higher than the control groups but they were significantly lower than the level of the CM group. Creatinine levels of the NACCM group were significantly higher than the CAPECM group. Malondialdehyde levels were significantly lower in CAPECM and NACCM groups than the CM group. CONCLUSION CAPE might protect renal structure and functions as well as NAC against CM injury.

Should Forensic Autopsies Be a Source for Medical Education? A Preliminary Study

Background: Practical anatomy sessions including dissection of cadavers are essential for anatomy courses. There are many difficulties in obtaining cadavers. In addition, hardened and discolored cadavers that are fixed with formaldehyde look unrealistic and generate apathy among students. Purpose: We considered that forensic autopsies may be used as ancillary and supportive practice in anatomy education. Methods: We invited the participation of Year 2 medical students in suitable forensic autopsy cases during the course of one year. Specialists of forensic medicine and anatomy provided theoretical support through talks in their specialized fields during the autopsy. At the end of the semester, feedback questionnaire forms were prepared and the students were asked to evaluate these sessions. Results: Forty students participated in the evaluation by completing the questionnaire. Students made positive statements about adequacy of the time of the application, consistency of the structures with theoretical and practical issues shown in anatomy lectures, and necessary explanations of the lecturers during and after the application. Conclusion: We think that forensic autopsies are an attractive supplementary educational model, and we have decided to continue the forensic autopsy practices. We believe that further studies on the evaluation of the sessions using a larger student population will lead to more conclusive results.