Search results for "Redox"
showing 10 items of 619 documents
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…
Kidney donors and kidney transplants have abnormal aminothiol redox status, and are at increased risk of oxidative stress and reduced redox buffer ca…
2013
Abstract Objective Living kidney donors have been part of a successful kidney transplant programme in Norway for almost 50 years. Glomerular filtration rates (GFRs) have tended to remain stable at about 70% of pre-donation levels. Plasma total homocysteine (Hcy) has an inverse relationship to kidney function, and previous reports indicate elevated levels of Hcy in kidney donors. We wanted to examine the most important plasma aminothiols in kidney donors, i.e. Hcy, cysteine (Cys) and cysteinylglycine (CG) with their redox species. The aminothiol redox-system appears to be an integral part of the extracellular antioxidant defence system in the body. Design and methods Plasma concentrations of…
Exhaustive physical exercise causes oxidation of glutathione status in blood: Prevention by antioxidant administration
1992
We have studied the effect of exhaustive concentric physical exercise on glutathione redox status and the possible relationship between blood glutathione oxidation and blood lactate and pyruvate levels. Levels of oxidized glutathione (GSSG) in blood increase after exhaustive concentric physical exercise in trained humans. GSSG levels were 72% higher immediately after exercise than at rest. They returned to normal values 1 h after exercise. Blood reduced glutathione (GSH) levels did not change significantly after the exercise. We have found a linear relationship between GSSG-to-GSH and lactate-to-pyruvate ratios in human blood before, during, and after exhaustive exercise. In rats, physical…
Decreased cell proliferation and higher oxidative stress in fibroblasts from Down Syndrome fetuses. Preliminary study
2013
Abstract Down Syndrome is the most common chromosomal disease and is also known for its decreased incidence of solid tumors and its progeroid phenotype. Cellular and systemic oxidative stress has been considered as one of the Down Syndrome phenotype causes. We correlated, in a preliminary study, the fibroblast proliferation rate and different cell proliferation key regulators, like Rcan1 and the telomere length from Down Syndrome fetuses, with their oxidative stress profile and the Ribonucleic acid and protein expression of the main antioxidant enzymes together with their activity. Increased oxidized glutathione/glutathione ratio and high peroxide production were found in our cell model. Th…
The aminothiol redox status in haemodialysis patients does not improve with folate therapy.
2008
Patients on haemodialysis suffer from high cardiovascular morbidity and mortality, and oxidative stress may play a role in the pathophysiology of cardiovascular disease in these patients. Hyperhomocysteinemia is common in dialysis patients and may have pro-oxidant effects. Moreover, the redox status of the major plasma aminothiols (homocysteine [Hcy], cysteine and cysteinylglycine) may be regarded as a biomarker of oxidative stress. In the present study, we investigated the aminothiol redox status during a period of homocysteine-lowering therapy with folinic acid.In the first part of the study, 32 stable patients receiving maintenance haemodialysis were compared with 32 reference subjects. …
Late onset administration of oral antioxidants prevents age-related loss of motor co-ordination and brain mitochondrial DNA damage.
1999
We have studied the effect of aging on brain glutathione redox ratio, on brain mitochondrial DNA damage and on motor co-ordination in mice and the possible protective role of late onset administration of sulphur-containing antioxidants. Glutathione redox ratios change to a more oxidized state in whole brain with aging but the changes are much more pronounced when this ratio is measured in brain mitochondria. The levels of 8-oxo-7,8-dihydro-2 '-deoxyguanosine in mitochondrial DNA are much higher in the brain of old animals than in those of young ones. Late onset oral administration of sulphur-containing antioxidants partially prevents oxidation of mitochondrial glutathione and DNA. There is …
Action of metyrapone on the redox state of free nicotinamide-adenine dinucleotide and on oxygen consumption of perfused rat livers and isolated mitoc…
1971
Metyrapone [2-methyl-1,2-bis-(3-pyridyl)-1-propanone] in a concentration of 5 mM increased the lactate/pyruvate ratio and theΒ-hydroxybutyrate/ acetoacetate ratio in the perfusion fluid of the isolated rat liver by a factor of 6 indicating a considerable shift in the ratio of free [NAD]/[NADH] in both the cytoplasmic and the mitochondrial compartment. Oxygen uptake of the isolated liver was decreased to about one half. The onset of the inhibitory effect on the respiration of the isolated organ was immediate. The inhibition lasted for at least 1 h.
Oxidation of carboxylic acids in water at IrO2-Ta2O5 and Boron Doped Diamond anodes
2011
Abstract A detailed study was dedicated to the anodic oxidation of three carboxylic acids (namely, oxalic, formic and maleic acid) with the objective to evaluate in a systematic way the effect on the oxidation of carboxylic acids of numerous relevant parameters, including the nature and the concentration of the carboxylic acid, the alimentation regime (potentiostatic vs. amperostatic), the current density and the working potential values, the flowdynamic regime, the temperature and the nature of the electrode material. It was observed that the effect of some operative parameters strongly depends on the nature of the electrode and of the carboxylic acid. As an example, the efficacy of abatem…
Electrochemistry and Spectroelectrochemistry of Bismanganese Porphyrin-Corrole Dyads
2011
A series of homobimetallic manganese cofacial porphyrin-corrole dyads were synthesized and investigated as to their electrochemistry, spectroelectrochemistry, and ligand binding properties in nonaqueous media. Four dyads were investigated, each of which contained a Mn(III) corrole linked in a face-to-face arrangement with a Mn(III) porphyrin. The main difference between compounds in the series is the type of spacer, 9,9-dimethylxanthene, anthracene, dibenzofuran, or diphenylether, which determines the distance and interaction between the metallomacrocycles. Each redox process of the porphyrin-corrole dyads was assigned on the basis of spectroscopic and electrochemical data and by comparison…
A Raman calibration for the quantification of SO42-groups dissolved in silicate glasses: Application to natural melt inclusions
2017
Sulfur is an important volatile element involved in magmatic systems. Its quantification in silicate glasses relies on state-of-the-art techniques such as electronprobe microanalyses (EPMA) or X-ray absorption spectroscopy but is often complicated by the fact that S dissolved in silicate glasses can adopt several oxidation states (S6+for sulfates or S2-for sulfides). In the present work, we use micro-Raman spectroscopy on a series of silicate glasses to quantify the S content. The database is constituted by 47 silicate glasses of various compositions (natural and synthetic) with S content ranging from 1179 to 13 180 ppm. Most of the investigated glasses have been synthesized at high pressur…