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Öğe Association between mental stress & some antioxidant enzymes of seminal plasma(Wolters Kluwer Medknow Publications, 2005) Eskiocak, S; Gozen, AS; Kilic, AS; Mollat, SBackground & objectives: Mental stress, which is responsible for various disorders, is one of the most important medical and social problems. It is reported that mental stress causes abnormality in sperm quality. Most of the previous investigations done to study the association between mental stress and infertility were carried out with infertile men. Infertility itself and/or its therapy may lead to stress. Further, most studies investigating the association between psychological stress and semen quality have lacked information on biochemical parameters. In the present study, we investigated the effect of mental stress due to final exams on two important antioxidant enzymes of the seminal plasma, superoxide dismutase (SOD) and catalase in normal healthy medical students. Methods: Semen samples were collected from 27 healthy male volunteers, who were third semester students of a medical school, just before (stress period) and 10.19 +/- 0.83 wk after (non-stress period) the final examinations. Psychological stress of participants was measured by the State Trait Anxiety Inventory. After standard semen analysis, semen samples were centrifuged at 10,000 x g for 15 min. Superoxide dismutase (SOD) and catalase activities were measured in the seminal plasma. Results: During stress period, stress scores and SOD activities increased significantly compared to the non-stress period. Catalase activities showed no change. Spermatozoa concentrations, motility index and percentage of rapid progressive motility decreased tinder stress. Interpretation & conclusion: Our results indicated that mental stress negatively affected semen quality. Increase in SOD activities led to poor quality of semen parameters.Öğe The effects of taking chronic nitrate by drinking water on thyroid functions and morphology(Springer, 2005) Eskiocak, S; Dundar, C; Basoglu, T; Altaner, SNitrate incorporation in humans takes place via drinking water and food. The water used for drinking and cooking in the goitrous areas is high in nitrate content. The aim of the present study was to evaluate both chronic effects and the dose-response relationship of nitrate on thyroid functions. A total of rats were divided into 5 work groups and sodium nitrate was added to their drinking water in different concentrations (0, 50, 100, 250 and 500 mg/l) over a 30-week period. The radioiodine uptake of thyroid was decreased in the 50 mg/l nitrate group, whereas it was increased in the 250 and 500 mg/l nitrate groups as compared to control. All hormones of thyroid gland except total thyroxine and thyroid-stimulating hormone were decreased in the 50, 250 and 500 mg/l nitrate groups. However, the level of total thyroxin was increased in the 100 mg/l nitrate group. Thyroid gland weights were increased in all experimental groups. Histomorphological changes were observed in the 250 and 500 mg/l nitrate groups. These findings suggest that nitrate impairs thyroid function involving the hypothalamo-hypophysio-thyroid axis. This observation could contribute to the current discussion about the acceptable daily intake of nitrate, as well as drinking water nitrate standard safety margins.Öğe Glutathione and free sulphydryl content of seminal plasma in healthy medical students during and after exam stress(Oxford Univ Press, 2005) Eskiocak, S; Gozen, AS; Yapar, SB; Tavas, F; Kilic, AS; Eskiocak, MBACKGROUND: It has been reported that there is a relationship between stress and infertility. The mechanisms of stress-related semen quality alterations have not been fully elucidated. In the present study, we investigated the effect of examination stress on seminal glutathione and free sulphydryl content and sperm quality. METHODS: Semen samples were collected from 34 healthy volunteers who were students of medical school in the fourth semester just before (stress period) and 3 months after (non-stress period) their final examinations. Their psychological examination stress was measured by the State Trait Anxiety Inventory (STAI) questionnaire. After standard semen analysis, semen samples were centrifuged at 10 000g for 15 min. Glutathione and free sulphydryl concentration of seminal plasma were measured. RESULTS: During the period of examination stress, the glutathione and free sulphydryl content of seminal plasma and the motility index of spermatozoa were significantly lower, whereas the percentage of morphologically abnormal spermatozoa was higher, than during the non-stress period (P < 0.001, for all). An association between seminal plasma glutathione and motility index was observed at both periods (P < 0.05 and P < 0.01, respectively). CONCLUSIONS: This study demonstrated that glutathione and free sulphydryl levels in seminal plasma decreased in subjects undergoing examination stress. Furthermore, poor sperm quality may be due to loss of glutathione and free sulphydryl content of seminal plasma.Öğe Importance of internal mammary artery perfusion in cardiac ischemia and reperfusion(Sage Publications Ltd, 2003) Ege, T; Eskiocak, S; Yuksel, V; Taskiran, A; Duran, EPurpose: Our purpose was to investigate the changes in antioxidant defense systems due to internal mammary artery (IMA) perfusion during coronary artery bypass graft (CABG) operations in which proximal anastomoses were completed under partial bypass with the aid of a side-biting clamp. Material and Method: Twenty-five patients to be studied were divided into two groups according to the criterion of whether during proximal anastomoses left internal mammary artery (LIMA) perfusion was applied (n = 15, LIMA group) or not (n = 10, non-LIMA group). The erythrocyte catalase (CAT), superoxide dismutase (SOD), serum lipid peroxidation (LPO) products and whole blood reduced glutathione (GSH) levels were measured in the blood samples taken from the coronary sinus before cardiopulmonary bypass (CPB) (t(1)), before declamping (t(2)), at the 5th min after declamping (t(3)) at the 5th (t(4)) and 15th (t(5)) min after removing the side-biting clamp. Results: While erythrocyte CAT enzyme activity decreases in both groups after the basal measurements, no significant difference was detected between the groups. Although the GSH levels did not differ at t(1), t(2) and t(3), they were found to be higher in the LIMA group at t(4) (p = 0.006) and t(5) (p = 0.021). The erythrocyte SOD enzyme activity decreased after the basal measurements in both groups, but this reduction was less in the LIMA group at t(4) (p = 0.034) and t(5) (p = 0.018) compared to the other group. LPO products rose in both groups when reperfusion started after declamping. The levels of LPO products were significantly higher at t(4) and t(5) in the non-LIMA group than the other group (p = 0.011 and p = 0.008). Conclusion: If proximal anastomoses of coronary grafts are completed under partial bypass, permitting LIMA perfusion during this procedure will be beneficial to antioxidant defense systems.Öğe Inhibition of iNOS with S-methylisothiourea was impaired in wound heating in caustic esophageal burn(Elsevier Ireland Ltd, 2005) Basaran, UN; Eskiocak, S; Altaner, S; Ture, M; Yapar, SBObjective: Stricture formation is a late complication of caustic esophageal burn, which is a common problem in childhood. For this reason, this experimental study was designed to observe the possible effect of nitric oxide on heating and fibrosis formation in caustic esophageal burns. Materials and methods: The rats were divided into five groups. Group A (n = 12) received sham burn and treatment with saline injection. Group B (n = 34) received caustic burn. Rats in group C (n = 31), were given water supplement with 10 g/L L-arginine that was started 24 In preoperatively and continued until postoperative day 4. In group D (n = 21), S-methylisothiourea (SMT, specific inducible nitric oxide synthase (iNOS) inhibitor), was injected at a dose of 3 mg/kg i.p. at 30 min before caustic burn, and similar dose was reinjected immediatety after caustic burn. SMT 6 mg/kg/day injections continued for 4 days Long. In group E (n = 22), N omega-nitro-L-arginine (L-NNA, nonspecific nitric oxide synthase (NOS) inhibitor) was injected at a dose of 15 mg/kg i.p. at 30 min before caustic burn, and similar dose was reinjected immediately after caustic burn. L-NNA 30 mg/kg/day continues for 4 days. Results: Dead rates were significantly higher in group Ethan in groups A-D. The mean hydroxyproline levels in esophageal. tissue were significantly lower in groups A and B than in group D. Histopathologically, tissue damage scores in the esophageal tissue were higher in group D than in groups A-C. Conclusions: Inhibition of iNOS with SMT was impaired in wound heating due to caustic esophageal burn and provoked collagen accumulation at a later period. Those effects may due to inhibition of antioxidant, immunomodulatory and antifibrotic effects of NO. (c) 2004 Elsevier Ireland Ltd. All rights reserved.Öğe The protective role of melatonin in experimental hypoxic brain damage(Blackwell Publishing, 2005) Tütüncüler, F; Eskiocak, S; Basaran, ÜN; Ekuklu, G; Ayvaz, S; Vatansever, ÜBackground: It is known that oxygen-derived free radicals play an important role in the pathogenesis of brain injury. Melatonin is a powerful scavenger of the oxygen free radicals. In this study, the protective effect of melatonin against the damage inflicted by reactive oxygen species during brain hypoxia was investigated in newborn rats using biochemical parameters. Methods: For biochemical analyses, the levels of lipid peroxidation product (malondialdehyde ([MDA]), levels of reduced glutathione (GSH) and the activities of superoxide dismutase (SOD) and catalase (CAT) were estimated. Results: After the third day of brain hypoxia, the brain levels of MDA increased. Pretreatment of animals with melatonin abolished the rise in MDA induced by hypoxia. GSH concentration did not increase by pretreatment with melatonin. Additonally, the activities of two antioxidative enzymes (SOD and CAT) decreased after the experimental period with melatonin only preventing the change of CAT. The activity of SOD was not influenced by melatonin administration as expected. Conclusion: In this experimental study, exogenously administered melatonin effectively protected against brain injury by oxidative stress. This protective effect of melatonin may be due to its direct scavenger activity and activation of CAT. Thus, melatonin may potentially be useful in the treatment of neurodegenerative conditions that may involve free radical production, such as perinatal hypoxia.
