Browsing by Author "Duman C."

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    Effects of defibrotide on aorta and brain malondialdehyde and antioxidants in cholesterol-induced atherosclerotic rabbits
    (2000) Aydemir E.O.; Duman C.; Çelik H.A.; Turgan N.; Uysal A.; Mutaf I.; Habif S.; Özmen D.; Nişli N.; Bayındır O.
    The effects of a high-cholesterol diet in the presence and absence of defibrotide, a single-stranded polydeoxyribonucleotide compound, on the lipid peroxidation product malondialdehyde, endogenous antioxidant enzymes catalase, glutathione peroxidase, and the antioxidant thiol compound GSH were investigated. Forty male New Zeland white rabbits were divided into four groups each consisting of 10 rabbits. Group I received a regular rabbit chow diet and group II 1% cholesterol plus regular chow, group III was given defibrotide (60 mg/kg per day p.o. in water) and was fed with regular chow, and group IV received defibrotide plus 1% cholesterol for 9 weeks. Blood cholesterol and malondialdehyde, catalase, glutathione peroxidase, and GSH were determined before starting the experimental diet regimen (basal). After 9 weeks, the same parameters were determined in blood, aorta, and brain tissues (end -experiment). Aortic tissue was examined under a light microscope for morphological alterations indicative of atherosclerosis. The increase in serum total cholesterol was greater in group II than group IV. Plasma malondialdehyde in group II was higher than in group III. Brain malondialdehyde in group II was higher than all other groups, and aortic malondialdehyde in this group was higher than group I and III. Serum catalase activity decreased in group II and increased in group III, compared with basal values. Brain catalase activity in group I was higher than group II, and aorta catalase in group IV was higher than in group I and III. Blood glutathione peroxidase activity in group III and IV was higher than basal. GSH concentrations decreased significantly in the cholesterol-fed groups (group II and IV). Histological alterations in the cholesterol-fed groups were more pronounced in group II. The increased levels of malondialdehyde in plasma, aorta, and brain tissue of group II suggest a role of oxygen free radicals in the pathogenesis of cholesterol-induced atherosclerosis. The higher malondialdehyde values in the brain tissues of animals in group II compared with group IV suggest a protective role of defibrotide in the brain against lipid peroxidation in the oxidant stress of cholesterol-induced atherosclerosis. Increased catalase activities in the blood and aortic tissues and increased glutathione peroxidase activities in the blood of rabbits receiving defibrotide suggest an induction of these antioxidant enzyme activities by defibrotide. These results imply that anti-atherosclerotic, anti-ischemic effects of this drug may be due to the beneficial effects on the oxidant-antioxidant balance of various tissues.
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    Age and gender dependent alterations in the activities of glutathione related enzymes in healthy subjects
    (2001) Habif S.; Mutaf I.; Turgan N.; Onur E.; Duman C.; Özmen D.; Bayindir O.
    Objectives: Oxidative stress as a result of increased free radical production is implicated in the pathogenesis of several diseases. Specific antioxidant enzymes have a crucial role in the prevention of these deleterious effects. Since the activities of these enzymes differ significantly in different populations and seem to be affected by various environmental factors, in this study we aimed to determine the reference values of glutathione related antioxidant enzyme activities in the erythrocytes of healthy subjects and to investigate the possible variations as a function of age and gender in a healthy Turkish Mediterranean population. Design and methods: 130 healthy subjects (12-90 yr, 82 females, 48 males) were divided into six different age groups. Erythrocyte glutathione peroxidase (GSH-PX), glutathione reductase (GR) and glutathione-s-transferase (GST) activities were measured on a Hitachi 704 autoanalyser by the modification of previously described manual UV spectrophotometric methods. Results: No significant differences were observed in erythrocyte GSH-PX, GR and GST activities between different age groups. Overall, GST activities were significantly higher in females compared with males (8.08 ± 1.39, 6.88 ± 1.51 U/g Hb respectively, mean ± SD, p < 0.001). A significant positive correlation between GSH-PX and GR activities was observed (r = 0.49, p < 0.001). Conclusion: The results of this study suggested that the activities of GSH-PX, GR and GST did not depend. GST activities overall were higher in females. The reference values that we obtained were different than the previous reports. This situation implies that each population should determine its own reference values and should investigate the influence of environmental factors and life style habits on the activities of these enzymes that constitute a major part of the antioxidant defense system in the human organism. © 2002 The Canadian Society of Clinical Chemists. All rights reserved.