Browsing by Author "Öztürk, HS"

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Aspirin Enhances Myocardial Inducible Nitric Oxide Synthase Activity in Guinea Pigs
(Elsevier Science Bv, 1999) Durak, I; Karaayvaz, M; Öztürk, HS
Cisplatin Induces Acute Renal Failure by Impairing Antioxidant System in Guinea Pigs
(Taylor & Francis Ltd, 2002) Durak, I; Özbek, H; Karaayvaz, M; Öztürk, HS
This study aims to investigate the role of oxidants in cisplatin-induced nephrotoxicity. Cisplatin was administered intraperitoneally (i.p.) in a single dose (5mg/kg) and guinea pigs were killed either after 24h or 7 days. The same experiment was performed using animals treated with vitamins C and E combination and a natural antioxidant extract (SARMEX((R))). The kidneys were then removed to be used in the analyses. Blood samples were also obtained from the animals to be used in routine biochemical assays. Twenty-four hours after treatment there was a significant decrease in the renal activities of total superoxide scavenger activity (TSSA), superoxide dismutase (SOD) and catalase (CAT) accompanied by a rise in malondialdehyde (MDA) levels. After 7 days, the fall in kidney enzymatic activities was far greater, while the increase in blood urea (BUN) and creatinine (CRE) was marked. Treatment with antioxidants causes significant increases in renal TSSA (7 day), non-enzymatic superoxide scavenger activity (NSSA) (24h and 7 day) and SOD (7 day) activities, does not change glutathione peroxidase (GSH-Px) activity and decreases renal MDA (24h and 7 day), blood BUN (7 day) and CRE (7 day) levels. Our results suggest that cisplatin treatment impairs both enzymatic and non-enzymatic antioxidant systems and causes peroxidation in the renal tissue, which leads to kidney failure. Antioxidant supplementation strengthens the renal antioxidant system, eliminates oxidation reactions, and prevents cisplatin-induced kidney failure.
Effects of Garlic Extract Consumption on Blood Lipid and Oxidant/Antioxidant Parameters in Humans With High Blood Cholesterol
(Elsevier Science inc, 2004) Durak, I; Kavutcu, M; Aytaç, B; Avci, A; Devrim, E; Özbek, H; Öztürk, HS
Effects of garlic extract supplementation on blood lipid profile and oxidant/antioxidant status were investigated in volunteer subjects with high blood cholesterol. A total of 23 volunteer subjects with high blood cholesterol (>5.98 mmol/L) participated in the study. Of them, 13 patients were evaluated as a hypertensive group and the others a normotensive group. Before (first sample) and after (second sample) garlic extract consumption for 4 months, routine blood analyses including lipid parameters and liver and kidney function tests were performed. Additionally, blood oxidant (malondialdehyde [MDA], oxidation resistance [OR]), and antioxidant (antioxidant potential [AOP], nonenzymatic superoxide radical scavenger activity [NSSA]) parameters were measured. Serum total cholesterol, low-density lipoprotein (LDL) and very-low-density lipoprotein (VLDL) cholesterols, and triglyceride levels were found to be significantly lowered, but HDL high-density lipoprotein cholesterol level increased after the extract use. The total:HDL cholesterol ratio was also found to be significantly decreased after the extract use. There were no meaningful differences with regard to other routine biochemical parameters. Additionally, blood AOP, OR, and NSSA values were found increased and MDA level decreased in the second samples relative to the first ones. Systolic and diastolic blood pressure values were also found to be significantly lowered after extract supplementation in the hypertensive group, but no similar changes were observed in the normotensive group. We conclude that garlic extract supplementation improves blood lipid profile, strengthens blood antioxidant potential, and causes significant reductions in systolic and diastolic blood pressures. It also leads to a decrease in the level of oxidation product (MDA) in the blood samples, which demonstrates reduced oxidation reactions in the body. (C) 2004 Elsevier Inc. All rights reserved.