Search results for " radicals"
showing 10 items of 192 documents
Effect of xanthine oxidase-generated extracellular superoxide on skeletal muscle force generation
2009
Skeletal muscle contractions increase superoxide anion in skeletal muscle extracellular space. We tested the hypotheses that 1) after an isometric contraction protocol, xanthine oxidase (XO) activity is a source of superoxide anion in the extracellular space of skeletal muscle and 2) the increase in XO-derived extracellular superoxide anion during contractions affects skeletal muscle contractile function. Superoxide anion was monitored in the extracellular space of mouse gastrocnemius muscles by following the reduction of cytochrome c in muscle microdialysates. A 15-min protocol of nondamaging isometric contractions increased the reduction of cytochrome c in microdialysates, indicating an …
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…
The Free Oxygen Radicals Test (FORT) to assess circulating oxidative stress in patients with acute myocardial infarction
2010
International audience; Background and aim: Reactive oxygen species (ROS) play an important role in the pathogenesis of many diseases including cardiovascular diseases. Several methods have been developed for the direct or indirect measurement of oxygen free radical and its by-products. The current study was designed to validate the new Free Oxygen Radicals Test (FORT) and to investigate the potential relationships between ROS and clinical or biological factors in male patients with acute myocardial infarction (AMI). Methods: We analysed FORT values in samples from 66 patients with AMI. Results: FORT values ranged from 324 to 1198 FORT units, with a median value of 581 (494-754) FORT units.…
Effect of ischaemic preconditioning, cardiopulmonary bypass and myocardial ischaemic/reperfusion on free radical generation in CABG patients.
2001
Abstract Objective: To investigate the free radicals (FR) generation after ischaemic preconditioning and cardiopulmonary bypass and during reperfusion in CABG patients, and the role of ischaemic preconditioning. Methods: Forty-three CABG patients were randomised into an ischaemic preconditioning and a control group. The protocol for ischaemic preconditioning was two cycles of 2-min ischaemia followed by 3-min reperfusion. Free radicals were measured using electron spin resonance spectroscopy. Global and right heart functions were collected. Results: The free radicals generation in coronary sinus blood in the ischaemic preconditioning group was 9.7 and 16.6% after the ischaemic preconditioni…
Decreased plasma soluble RAGE in patients with hypercholesterolemia: Effects of statins
2007
The receptor for advanced glycation endproducts (RAGE) is overexpressed at sites of vascular pathology. A soluble RAGE isoform (sRAGE) neutralizes the ligand-mediated damage by acting as a decoy. We hypothesized that in hypercholesterolemia up-regulation of the ligand-RAGE axis may bridge impairment of nitric oxide biosynthesis with oxidative stress. We measured in 60 hypercholesterolemic patients and 20 controls plasma total sRAGE levels, urinary 8-iso-prostaglandin (PG) F(2alpha) excretion, and plasma levels of asymmetric dimethylarginine (ADMA). The effects of two structurally different statins (pravastatin and atorvastatin) on these parameters were analyzed in 20 hypercholesterolemic su…
Abnormalities of mitochondrial functioning can partly explain the metabolic disorders encountered in sarcopenic gastrocnemius.
2007
International audience; Aging triggers several abnormalities in muscle glycolytic fibers including increased proteolysis, reactive oxygen species (ROS) production and apoptosis. Since the mitochondria are the main site of substrate oxidation, ROS production and programmed cell death, we tried to know whether the cellular disorders encountered in sarcopenia are due to abnormal mitochondrial functioning. Gastrocnemius mitochondria were extracted from adult (6 months) and aged (21 months) male Wistar rats. Respiration parameters, opening of the permeability transition pore and ROS production, with either glutamate (amino acid metabolism) or pyruvate (glucose metabolism) as a respiration substr…
Response charactterization of ammonium tartrate solid state pellets for ESR dosimetry with radiotherapeutic photon and electron beams.
2001
Solid state pellets (1 mm thick) for electron spin resonance (ESR) dosimetry were made using ammonium tartrate as the radiation-sensitive substance. Their behaviour was experimentally investigated as a function of dose with 60Co gamma rays. The calibration function obtained permits measurements of absorbed dose in the 2-50 Gy range, with a combined uncertainty of +/-4%. The lowest detectable dose was about 0.5 Gy. These properties are comparable with or even better than those of ESR dosimeters made from other materials. The time stability of the ESR signal of ammonium tartrate dosimeters at different storage conditions after irradiation was studied. A rather complex behaviour was observed, …
RADICAL DISTRIBUTIONS IN AMMONIUM TARTRATE SINGLE CRYSTALS EXPOSED TO PHOTON AND NEUTRON BEAMS
2014
The radiation therapy carried out by means of heavy charged particles (such as carbon ions) and neutrons is rapidly becoming widespread worldwide. The success of these radiation therapies relies on the high density of energy released by these particles or by secondary particles produced after primary interaction with matter. The biological damages produced by ionising radiations in tissues and cells depend more properly on the energy released per unit pathlength, which is the linear energy transfer and which determines the radiation quality. To improve the therapy effectiveness, it is necessary to grasp the mechanisms of free radical production and distribution after irradiation with these …
Electron spin resonance as a tool to monitor the influence of novel processing technologies on food properties
2020
Abstract Background Nowadays, electron spin resonance (ESR) is widely used as a powerful, non-destructive and very sensitive technique for the detection of free radicals in food systems. It can be applied for the direct identification of highly reactive oxygen species, organic and inorganic paramagnetic species and screening of food for potential toxicity. Its applications cover investigating food oxidative stability and properties of irradiated foods including fruits and vegetables, meats and fishes, spices, cereal grains, and oil seeds. Scope and approach This review aims at providing specialists in food science and industry with the fundamentals of ESR spectroscopy, typical radicals pres…