Biomedical subjects

Müjdat Uysal

Publications and source records attributed to Müjdat Uysal.

25 records · Page 2Linked to original sources

PubMed2002

Increased lipid peroxidation in serum and low-density lipoproteins associated with aging in humans.

This study was carried out in 140 healthy subjects who were divided into three subgroups of age: young (21-40 years), mature (41-60 years), and elderly (61-85 years) to investigate lipid peroxides and the antioxidant system in serum and low-density lipoproteins (LDL). Serum levels of cholesterol and LDL-cholesterol increased with age. The elderly group was found to have higher polyunsaturated fatty acid (PUFA) levels, thiobarbituric acid reactive substances (TBARS), diene conjugates, and lower cholesterol-adjusted vitamin E levels and antioxidant activity (AOA) as compared to the young group. No age-related difference was detected in serum vitamin C levels. Age correlated positively with serum cholesterol, LDL-cholesterol, PUFA, TBARS, diene conjugates, and negatively with cholesterol-adjusted vitamin E levels and AOA. In addition, endogenous LDL diene conjugate levels and the susceptibility of LDL to copper-induced lipid peroxidation increased in elderly subjects as compared with young subjects. In addition, positive correlations were detected between age and LDL endogenous diene conjugate levels and TBARS formation after copper incubation. However, the susceptibility of whole serum to copper-induced lipid peroxidation did not change in young and elderly subjects. Our results show that endogenous lipid peroxide levels in serum and LDL, and the susceptibility of LDL to copper-induced oxidation, increased with aging in humans.

Adult↗

PubMed2002

Taurine treatment reduces hepatic lipids and oxidative stress in chronically ethanol-treated rats.

In this study, we evaluated whether taurine treatment has a protective effect on the prooxidant-antioxidant state following chronic ethanol treatment in rats. Rats were given water containing 20% ethanol (v/v) as drinking water for 3 months. Chronic ethanol treatment in drinking water resulted in increased oxidative stress in the liver of rats. Taurine treatment was performed by adding 1% taurine (w/v) to the drinking water plus injection (400 mg/kg body weight) intraperitoneally 3 times/week for 28 d after ethanol cessation in chronically ethanol-treatad rats. This treatment starting after ethanol cessation caused a significant decreases in serum transaminase activities and hepatic total lipid, triglyceride, malondialdehyde, and diene conjugate levels and significant increases in hepatic glutathione, vitamin E, and vitamin C levels, but did not alter the activities of superoxide dismutase, glutathione peroxidase, and glutathione transferase in the liver as compared with chronically ethanol-treated rats. Accordingly, we propose that taurine has a restorative effect on ethanol-induced hepatic damage by decreasing oxidative stress.

Animals↗

PubMed2002

Hepatic mitochondrial prooxidant and antioxidant status in ethanol-induced liver injury in rats.

In this study, prooxidant and antioxidant status in liver homogenates and their mitochondrial fractions were investigated in both chronic and chronic plus acute ethanol-treated rats. Increases in serum transaminase activities, as well as increases in total lipid, triglyceride, malondialdehyde (MDA) and diene conjugate (DC) levels and decreases in glutathione (GSH), vitamin E and vitamin C levels, have been observed in liver homogenates following chronic ethanol treatment (20% ethanol, v/v as drinking water for 3 months), but CuZn-superoxide dismutase (CuZnSOD), glutathione peroxidase (GSH-Px) and glutathione transferase (GST) activities remained unchanged in postmitochondrial fractions. When an acute dose of ethanol (5 g/kg, i.p.) was given rats which had received ethanol chronically, serum transaminase activities and hepatic lipid and MDA and DC levels increased further, but GSH levels and antioxidant enzymes decreased more compared to the chronic ethanol-treated rats. There were no significant differences in the levels of MDA, DC and protein carbonyl and the activities of GSH-Px and GST in the hepatic mitochondrial fraction of rats following both chronic and chronic plus acute treatments. Mn-superoxide dismutase (MnSOD) activities increased in both groups, but mitochondrial GSH levels decreased only after chronic plus acute treatment. Therefore, we suggest that the increase in MnSOD activity may play an important role in the regulation of mitochondrial susceptibility against ethanol-induced oxidative stress.

Animals↗

PubMed2002

Improving effect of dietary taurine supplementation on the oxidative stress and lipid levels in the plasma, liver and aorta of rabbits fed on a high-cholesterol diet.

The effect of a high-cholesterol diet with or without taurine on lipids and oxidative stress in the plasma, liver and aorta of rabbits was investigated. The animals were maintained on a basal diet (control), a high-cholesterol diet (HC, 1% w/w), or a high- cholesterol diet supplemented with taurine (HCHT, 2.5% w/w) for two months. Taurine has an ameliorating effect on atherosclerosis together with a decreasing effect on the cholesterol and triglyceride levels in rabbits fed on an HC diet. The HCHT diet caused a significant decrease in the malondialdehyde (MDA) and diene conjugate (DC) levels in the plasma, liver and aorta of rabbits as compared to the HC group. This treatment did not alter the antioxidant system in the liver of rabbits in the HC group. Our findings indicate that taurine ameliorated oxidative stress and cholesterol accumulation in the aorta of rabbits fed on the HC diet and that this effect may be related to its antioxidative potential as well as its reducing effect on serum lipids.

Animals↗

PubMed2002

Effects of added dietary taurine on erythrocyte lipids and oxidative stress in rabbits fed a high cholesterol diet.

Lipid peroxidation leads to damage of polyunsaturated fatty acids of membrane phospholipids. The contribution of oxidative stress to hypercholesterolemia-induced hemolytic anemia and the effects of addition of taurine on erythrocyte lipid composition, oxidative stress, and hematological data were studied in rabbits fed on a high cholesterol (HC) diet (1%, w/w) for 2 months. The effects of taurine on erythrocyte hemolysis and H2O2-induced lipid peroxidation were investigated in normal rabbit erythrocytes in vitro. The HC diet resulted in increases in plasma lipids and lipid peroxide levels as well as increases in cholesterol levels and the cholesterol:phospholipid ratio in the erythrocytes. This diet caused a hemolytic anemia, but lipid peroxide levels remained unchanged in the erythrocytes of the rabbits. Taurine (2.5%, w/w) added to the food has an ameliorating effect on plasma lipids and lipid peroxide levels in rabbits fed on a HC diet. This treatment also caused decreases in elevated erythrocyte cholesterol levels and cholesterol:phospholipid ratio due to the HC diet, but it did not prevent the hemolytic anemia and did not change erythrocyte lipid peroxide levels. In addition, in an in vitro study, taurine did not protect erythrocytes against H2O2-induced hemolysis or lipid peroxidation. These results show that the HC diet causes hemolytic anemia without any changes in erythrocyte lipid peroxidation, and taurine treatment was not effective against hemolytic anemia caused by the HC diet.

Anemia, Hemolytic↗

PubMed2002

The investigation of prooxidant-antioxidant balance in serum of children with family histories of essential hypertension.

It has been accepted that essential hypertension is associated with a loss of the balance between prooxidation and antioxidation. Thus, excessive oxygen free radical production may be an early event in the pathogenesis of hypertension. To compare lipid peroxidation and antioxidant system in serum of children of essential hypertensive and normotensive parents. Serum malondialdehyde (MDA) levels were measured spectrofluorometrically. Antioxidant activity, glutathione peroxidase, selenium levels in serum were measured as indices of antioxidant power. The peroxidation of apo B containing lipoproteins (VLDL+LDL) was measured as the susceptibility to oxidation in vitro. Serum MDA levels increased, but no marked differences in total antioxidant activity, glutathione peroxidase activity, selenium levels and VLDL+LDL oxidation were found in serum of children with family histories of essential hypertension as compared to children of normotensive parents.

Adolescent↗

PubMedDate not supplied

Resistance of erythrocytes to lipid peroxidation in cirrhotic rats.

BACKGROUND: The aim of the present study was to investigate erythrocyte prooxidant-antioxidant balance in relation to liver and plasma lipid peroxidation in thioacetamide (TAA)-induced liver cirrhosis in rats. METHODS: Liver cirrhosis was produced by the administration of TAA (0.3 g/L of tap water) for a period of 3 months in rats. Serum, liver and erythrocyte lipid peroxide levels as well as liver glutathione (GSH) levels and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were determined in cirrhotic rats. RESULTS: Hepatic cirrhosis was assessed by biochemical and histopathological findings. Serum alanine transaminase (ALT) and aspartate transaminase (AST) activities and malondialdehyde (MDA) levels increased in cirrhotic rats. This treatment caused increased MDA and diene conjugate (DC) levels as well as decreased GSH levels and GSH-Px activities in the liver of cirrhotic rats. In these conditions, no significant changes in erythrocyte cholesterol, phospholipid levels as well as endogenous DC, and GSH levels and spontaneous hemolysis values were observed in erythrocytes of rats with TAA-induced liver cirrhosis. However, H(2)O(2)-induced MDA levels were detected to decrease significantly in erythrocytes of cirrhotic rats. CONCLUSIONS: Our results indicate that erythrocytes of TAA-induced cirrhotic rats have a resistance against peroxidative stress in contrast to the findings in plasma and liver.

Animals↗