Search results for "Disulfide"
showing 10 items of 171 documents
Xanthine oxidase is involved in exercise-induced oxidative stress in chronic obstructive pulmonary disease
1999
In the present study, we hypothesized that exhaustive exercise in patients with chronic obstructive pulmonary disease (COPD) results in glutathione oxidation and lipid peroxidation and that xanthine oxidase (XO) contributes to free radical generation during exercise. COPD patients performed incremental cycle ergometry until exhaustion with (n = 8) or without (n = 8) prior treatment with allopurinol, an XO inhibitor. Reduced (GSH) and oxidized glutathione (GSSG) and lipid peroxides [malondialdehyde (MDA)] were measured in arterial blood. In nontreated COPD patients, maximal exercise (approximately 75 W) resulted in a significant increase in the GSSG-to-GSH ratio (4. 6 +/- 0.9% at rest vs. 9.…
Blood Glutathione as an Index of Radiation-Induced Oxidative Stress in Mice and Humans
1997
Abstract The effect of x-rays on GSH and GSSG levels in blood was studied in mice and humans. An HPLC method that we recently developed was applied to accurately determine GSSG levels in blood. The glutathione redox status (GSH/GSSG) decreases after irradiation. This effect is mainly due to an increase in GSSG levels. Mice received single fraction radiotherapy, at total doses of 1.0 to 7.0 Gy. Changes in GSSG in mouse blood can be detected 10 min after irradiation and last for 6 h within a range of 2.0–7.0 Gy. The highest levels of GSSG (20.1 ± 2.9 μ M), a 4.7-fold increase as compared with controls) in mouse blood are found 2 h after radiation exposure (5 Gy). Breast and lung cancer patien…
Alpha-adrenergic modulation of glutathione metabolism in isolated rat hepatocytes.
1988
Glutathione metabolism was studied in isolated hepatocytes from 48-h starved rats. Phenylephrine (10 microM, final concentration) was incubated in the presence of a mixture of L-glutamine, glycine, L-serine, and L-methionine (at 10 times their normal plasma concentration). Alpha-adrenergic stimulation provoked a decrease in glutathione (GSH) synthesis. This effect was accompanied by an enhanced efflux of glutathione from the cells. Phenylephrine stimulated the rate of glutathione disulfide (GSSG) formation; however, this effect was clearly insufficient to explain the disappearance of GSH. Our results suggest that the decrease in cellular GSH levels observed under conditions of shock, stress…
Effect of aging on metabolic zonation in rat liver: acinar distribution of GSH metabolism.
1992
The effect of age on the glutathione antioxidant system and its acinar distribution in rat liver was studied. GSH/GSSG ratio in blood and liver was lower in old than in young rats. Hepatic glutathione peroxidase and glutathione S-transferase activities were higher in old than in young rats, whereas hepatic gamma-glutamyl transpeptidase activity was lower in old than in young rats. Glutathione reductase and glucose-6-phosphate dehydrogenase activities did not change with age in rat liver. Total glutathione levels and glutathione peroxidase activity were higher in periportal than in perivenous areas of young rats, but this heterogeneous distribution did not occur in old rats. No change with a…
Retinol, at concentrations greater than the physiological limit, induces oxidative stress and apoptosis in human dermal fibroblasts
2004
We have investigated the dose (in the range of microM) and time-dependent effects of four different retinoids (retinol, retinal, retinoic acid and retinol palmitate) on human dermal fibroblasts cultivated in vitro. Retinol and retinal, at a concentration of 20 microM, caused cell damage as evaluated by lactate dehydrogenase activity released into the culture medium. The oxidised glutathione (GSSG)/reduced glutathione (GSH) ratio and malondialdehyde production indicated that 20 microM of retinol provoked oxidative stress in the cultivated human fibroblasts. In the first 8 h after retinol treatment the levels of p53 and Bax proteins as well as caspase 3 activity increased, suggesting apoptoti…
Protection effect of endurance training against reoxygenation-induced injuries in rat heart
1990
Endurance training by swimming (219-229 h) resulted in a significant protection against hypoxia/reoxygenation-induced injuries in Langendorff-perfused rat hearts. The protection was manifested as improved flow characteristics and a smaller release of creatine kinase into the perfusate. The concentration of thiobarbituric acid reactive substances (TBARS) was lower in the trained than in the respective control hearts. The trained hearts also showed a lower reoxygenation-induced increase in TBARS. The myocardium of the right ventricle and that of the left subepimyocardium were the most affected by reoxygenation. The swimming program induced a decrease in the activities of catalase and glutath…
Mitochondrial glutathione oxidation correlates with age-associated oxidative damage to mitochondrial DNA
1996
Mitochondria may be primary targets of free radical damage associated with aging. We have found that mitochondrial glutathione is markedly oxidized with aging in rats and mice. The oxidized to reduced glutathione ratio rises with aging in the liver, kidney, and brain. The magnitude of these changes is much higher than that previously found in whole cells of any species previously studied. In the liver, this ratio (expressing GSSG as a percent of GSH) changed from 0.77 +/- 0.19% (n=5) in young rats to 2.47 +/- 1.25% (n=5) in old ones, i.e., 320% of the controls. In the brain and kidney, values for old rats were, respectively, 600 and 540% higher than those of young rats. A marked oxidation o…
Murine tissue factor disulfide mutation causes a bleeding phenotype with sex specific organ pathology and lethality.
2019
Tissue factor is highly expressed in sub-endothelial tissue. The extracellular allosteric disulfide bond Cys186-Cys209 of human tissue factor shows high evolutionary conservation and in vitro evidence suggests that it significantly contributes to tissue factor procoagulant activity. To investigate the role of this allosteric disulfide bond in vivo, we generated a C213G mutant tissue factor mouse by replacing Cys213 of the corresponding disulfide Cys190-Cys213 in murine tissue factor. A bleeding phenotype was prominent in homozygous C213G tissue factor mice. Pre-natal lethality of 1/3rd of homozygous offspring was observed between E9.5 and E14.5 associated with placental hemorrhages. After b…
Preterm Resuscitation With Low Oxygen Causes Less Oxidative Stress, Inflammation, and Chronic Lung Disease
2009
OBJECTIVE: The goal was to reduce adverse pulmonary adverse outcomes, oxidative stress, and inflammation in neonates of 24 to 28 weeks of gestation initially resuscitated with fractions of inspired oxygen of 30% or 90%. METHODS: Randomized assignment to receive 30% (N = 37) or 90% (N = 41) oxygen was performed. Targeted oxygen saturation values were 75% at 5 minutes and 85% at 10 minutes. Blood oxidized glutathione (GSSG)/reduced glutathione ratio and urinary o-tyrosine, 8-oxo-dihydroxyguanosine, and isoprostane levels, isofuran elimination, and plasma interleukin 8 and tumor necrosis factor α levels were determined. RESULTS: The low-oxygen group needed fewer days of oxygen supplementation …
Human leukocyte/endothelial cell interactions and mitochondrial dysfunction in type 2 diabetic patients and their association with silent myocardial …
2013
OBJECTIVE Diabetes is associated with oxidative stress and increased mortality, but a possible correlation between leukocyte-endothelium interactions, oxidative stress, and silent myocardial ischemia (SMI) is yet to be confirmed. RESEARCH DESIGN AND METHODS Mitochondrial dysfunction and interactions between leukocytes and human umbilical vein endothelial cells were evaluated in 200 type 2 diabetic patients (25 with SMI) and 60 body composition– and age-matched control subjects. A possible correlation between these parameters and the onset of SMI was explored, and anthropometric and metabolic parameters were also analyzed. RESULTS Waist, levels of triglycerides, proinflammatory cytokines (i…