Mehmet Birey

Antioxidant Defense Potential of Rabbit Renal Tissues after ESWL: Protective Effects of Antioxidant Vitamins

Antioxidant defense potential, malondialdehyde (MDA) levels, and relative hydroxyl radical (OH·) concentrations were measured in order to establish the effects of extracorporeal shock wave lithotripsy (ESWL) on free radical production and antioxidant defense potential of the rabbit kidney tissues. Electron microscopic examination was also performed to observe ultrastructural changes. The antioxidant defense potential of the ESWL-treated tissues was found to be reduced, and the MDA levels increased as compared with controls. Vitamin (vitamin E plus C combination) pretreatment ameliorated antioxidant defense potential in part, prevented increases in MDA levels in the ESWL-treated tissues, and increased the antioxidant defense potential in the control kidney tissues. After ESWL, a significant amount of OH· radical was measured in the affected tissue. This revealed the source of oxidant stress and peroxidation reactions in the ESWL-treated kidney tissue. Vitamin pretreatment caused significant reduction in the OH· radical concentration. In the electron microscopic investigation, some significant subcellular changes, such as endothelial injury, loss of foot processes, damage of glomerular basal membrane, etc., were observed in the ESWL-treated renal tissue slices. Vitamin pretreatment to a great extent prevented formation of these subcellular changes. Our results suggest that the antioxidant capacity of the kidney tissue was reduced after ESWL treatment and that the tissue was exposed to oxidant stress. Vitamin pretreatment exerted significant protection against the radical damage.

EPR of gamma irradiated single crystals of cholesteryl benzoate

The cholesteryl benzoate compound has been irradiated with 60Co-γ rays at room temperature. The irradiated samples have been examined for paramagnetic resonance, and in several cases the observed spectra could be identified with specific radicals. In each case the results have been considered in relation to the present knowledge of the radiation chemistry of the compound. The single crystals have been investigated between 123 and 300 K. The spectrum parameters are found to be temperature independent. Radiation damage centers are attributed to ĊHCH2 and ĊHCH2CH2 radicals. The g values and the hyperfine coupling constants of the unpaired electron with the protons were determined.

EPR study of γ-irradiated three-furancarboxylic acid

The electron paramagnetic resonance of γ-irradiated single crystals of three-furancarboxylic acid has been studied for different orientations of the crystals in a magnetic field. The radicals produced by γ-irradiation have been investigated between 123 and 350 K. The spectra were found to be temperature dependent, and radiation damage centers were attributed to the radical. The principal values of the g-tensor were determined. The results were found to be in good agreement with the existing literature data and theoretical predictions.

Impaired antioxidant defence in guinea pig heart tissues treated with halothane

PurposeTo investigate the effects of halothane and halothane plus vitamin E treatment on myocardial free radical metabolism in guinea pigs.MethodsFour groups of seven animals were studied; control, halothane, halothane plus vitamin E and vitamin E groups. In the halothane group, halothane 1.5% in oxygen was given for 90 min over three days. In the halothane plus vitamin E group, 300 rng · kg−1 · day−1 vitamin Eim was started three days before the first halothane treatment and continued for three days. Following sacrifice, the hearts were assayed for superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) and malondialdehyde (MDA) level was determined. Electron spin resonance (ESR) analysis and electron microscopy (EM) were also performed.ResultsIn the halothane group, SOD activities and MDA concentrations were increased compared with control and GSH-Px and CAT activities were decreased. In the halothane plus vitamin E group, there were no differences in enzyme activity compared with halothane alone but the MDA level was decreased. In the vitamin E group, enzyme activities were increased compared with control. Mainly the CF3CHCl radical was identified by ESR analysis in heart tissues exposed to halothane and the concentration of this radical was reduced by vitamin E. Electron microscopy showed cytoplasmic vacuolisation and dilation in sarcoplasmic reticulum in the heart tissues exposed to halothane: both were prevented by vitamin E.ConclusionAlthough halothane causes impairment in enzymatic antioxidant defence potential, due to lowered GSH-Px and CAT activity, and accelerates peroxidative reactions in the tissues affected, no subcellular damage occurred. Vitamin E may protect tissues against free radical attack by scavenging toxic free radicals formed in heart tissue during halothane anaesthesia.RésuméObjectifÉtudier les effets de l’halothane et de l’association halothane-vitamine E sur la production myocardique de radicaux libres.MéthodesL’étude portait sur quatre groupes de sept animaux: contrôle, halothane, halothane+vitamine E, et vitamine E. Le groupe halothane a reçu de l’halothane 1,5% en oxygène pendant 90 min pour 3 jours. Le groupe halothane+vitamine E a reçu une doseim de 300 mg · kg−1 · j−1 de vitamine E pendant trois jours avant un premier traitement a l’halothane. Une fois l’animal sacrifié, la superoxyde dismutase (SOD), la glutathion peroxydase (GSH-Px) et catalase (CAT), et la malondialdéhyde (MDA) ont été titrées dans le tissu cardiaque. La résonance paramagnétique électronique (RPÉ) et la microscopie électronique ont complété ces analyses.RésultatsDans le groupe halothane, l’activité de la SOD et la concentration de MDA augmentaient comparativement au contrôle et l’activité de la GSH-Px et de la CAT diminuait. Dans le groupe halothane+vitamine E, l’activité enzymatique ne changeait pas comparativement à l’halothane seul mais le niveau de MDA diminuait. Dans le groupe vitamine E, l’activité enzymatique augmentait comparativement au contrôle. Le radical CF3CHCl était principalement identifié par l’analyse RPÉ dans le tissu cardiaque exposé à l’halothane alors que la vitamine E diminuait la concentration de ce radical. La microscopie électronique révélait une vacuolisation et une dilatation cytoplasmiques du réticulum sarcoplasmique du tissu cardiaque exposé à l’halothane; la vitamine E prévenait ces effets.ConclusionMalgré l’altération par l’halothane de la capacité de protection enzymatique contre l’oxydation, due à la baisse de l’activité de la GSH-Px et de la CAT et l’accélération des réactions peroxydatives dans les tissus affectés, il n’y a pas eu de dommages infracellulaires. La vitamine E protège les tissus contre l’agression des radicaux libres en épurant les radicaux toxiques libérés dans le tissu cardiaque pendant l’anesthésie à l’halothane.

ELECTRON PARAMAGNETIC RESONANCE STUDY OF IRRADIATED TETRAMETHYL-4-PIPERIDION

The electron paramagnetic resonance of single crystals of tetramethyl-4-piperidion (TMP; C9H19NO) has been observed and analysed for different orientations of the crystal in the magnetic field, after being damaged at 300 K by γ-irradiation. The crystals have been investigated between 100 and 450 K. The spectra were found to be temperature dependent. The irradiation of TMP by γ-rays produces radicals at the nitrogen atoms in the molecule. The principal values of the hyperfine coupling tensor of the unpaired electron and the principal values of the g-tensor were determined. The results were found to be in good agreement with the existing literature data and theoretical predictions.

EPR study of γ-irradiated tetra-N-butylammonium iodide

The electron paramagnetic resonance of γ -irradiated single crystal of tetra-N-butylammonium iodide has been studied for different orientations of the crystals in a magnetic field. The radical produced by gamma irradiation has been investigated at 300 K. The spectra were found to be magnetic field dependent and radiation damage centers were attributed to the (C α H 2 C β H 2 C γ H 2 CH 3) radical. The principal values of the hyperfine coupling tensor of the unpaired electron with these atoms and the principal values of the g tensor were determined and the hyperfine coupling constants were verified by computer simulation. The results were found to be in good agreement with the existing literature data and theoretical predictions.

Electron paramagnetic resonance analysis of gamma irradiated 4-nitropyridine N-oxide single crystal

A free radical produced by 60Co- γ irradiation in single crystals of 4-nitropyridine N-oxide, C5H4N2O3, has been observed and analyzed for different orientations of the crystal in the magnetic field at the temperature between 120 and 450 K, using an Electron Paramagnetic Resonance (EPR) technique. The spectra were found to be temperature independent and the resonance form of the radical was attributed to the 4-nitropyridinium cation radical. The isotropic average value of the g-factor and the hyperfine splitting constants are obtained as g av = 2.01077, , , and . The measurements indicate that 70% of the unpaired electrons are localized on the N(1).

ESR of gamma irradiated single crystals of cholesteryl acetate and cholesteryl chloroformate

Cholesteryl acetate and cholesteryl chloroformate compounds have been irradiated with 60Co-γ rays at room temperatures. The irradiated samples have been examined for paramagnetic resonance, and the observed spectra in several cases have been identified with specific radicals. The results in each case have been considered in relation to the present knowledge of the radiation chemistry of the compound. The single crystals have been investigated between 120 and 300 K. The spectra are found to be temperature independent and radiation damage centers are attributed to ĊHCH2 radical for cholesteryl acetate and ĊH3 and ĊHCH2 CH2 CH2 radicals for cholesteryl chloroformate.

Electron paramagnetic resonance of γ-irradiation damage centers in fumaric acid dipotassium salt dihydrate

Electron paramagnetic resonance spectra of γ-irradiated single crystals of fumaric acid dipotassium salt dihydrate have been studied for different orientations of the crystal in a magnetic field. The radicals produced by γ-irradiation have been investigated between 123 and 300 K. The spectra were found to be temperature-independent, and radiation damage centers were attributed to the and radicals. The g factor and hyperfine coupling constants were found to be and ρ=0.76.

ESR of Gamma Irradiation Damage Centers in Single Crystals of Some Glutamic Acid Derivatives

Abstract We have observed four radicals in the ESR spectra of y-irradiated single crystals of some glutamic acid derivatives. These radicals, produced by gamma-irradiation, in single crystals of N-Acetyl-L-Glutamic acid, L-Glutamic acid and DL-Glutamic acid hydrochloride were identified as CH3CONH, -C3H5 , -CH, and -NH2 radicals respectively.