Showing papers on "Oxidative stress published in 1982"

The effect of diabetes on the activities of the peroxide metabolism enzymes.

Abstract: The lipid peroxidation and (of the peroxide metabolism enzymes) the catalase, superoxide dismutase and glutathione peroxidase activities were determined in red blood cell haemolysates from 20-35-year-old human diabetics of both sexes. The results were compared with the values for normal controls from the same age group. The diabetic haemolysates displayed significantly higher glutathione peroxidase and significantly lower superoxide dismutase activities. The lipid peroxidation too was significantly higher in the diabetic haemolysates. Diabetes was induced with alloxan or streptozotocin in rats, and the enzyme activities of the blood and organ homogenates were similarly compared; in these cases the total peroxidase activity. In experimental diabetes the previously-observed phenomenon of oxidative stress was confirmed; this may serve as a logical explanation for the occurrence of the later diabetic damage.

A possible role of xanthine oxidase in producing oxidative stress in the heart of chronically ethanol treated rats.

Abstract: Examination of hearts and livers of rats fed ethanol for 25-30 weeks showed significant increases in catalase and glutathione peroxidase activity. Further examination revealed that the xanthine dehydrogenase/oxidase activity ratio in both tissues were decreased, suggesting that an interconversion of the dehydrogenase into oxidase might have occurred. Such an interconversion would be expected to enhance the formation of superoxide anions during acetaldehyde metabolism by xanthine oxidase. Since a role of oxidative or free radical damage in the etiology of ethanol-induced liver pathology is becoming increasingly apparent, the observation that the biochemical changes in the heart and liver are comparable suggests that oxidative damage is involved in alcoholic pathology of the heart as well as liver.

Active oxygen metabolites and their action in the hepatocyte. Studies on chemiluminescence responses and alkane production.

Abstract: "Oxidative stress" takes place in animal tissues when the balance between the cellular defense mechanisms (glutathione cycle, superoxide dismutase, catalase, vitamin E, etc.) and conditions capable of triggering oxidative reactions is altered. The oxidative reactions which occur under a variety of conditions were assessed by two non-invasive methods, low-level chemiluminescence and volatile hydrocarbon production. Oxidative stress induced by hyperoxia or organic hydroperoxides in isolated hepatocytes or the perfused liver, respectively, is accompanied by low-level chemiluminescence, the intensity of which is enhanced upon perturbation of the glutathione cycle system, i.e., glutathione depletion and/or selenium deficiency. Oxidative stress during redox cycling of paraquat, when infused into the perfused liver, is not accompanied by light emission, whereas menadione, a substance also capable of redox cycling, was found to elicit photoemission under similar conditions. The basal rates of ethane release by the perfused liver are enhanced during oxidative conditions such as metabolism of hydroperoxides, paraquat redox cycling, and ethanol oxidation. Alkane release during the latter involves the participation of alcohol dehydrogenase and further products of ethanol oxidation, i.e., acetaldehyde, as well as free radicals in some stage of the process. In vivo ethane release by animals with adjuvant arthritis was found higher than in controls, presumably due to a systemic response of liver to inflammation.