Search results for "Peroxidation"

Reaction of melatonin with lipoperoxyl radicals in phospholipid bilayers.

1997

Melatonin, at 5 to 500 microM was incorporated in unilamellar soybean phosphatidylcholine (PC) liposomes, the peroxidation of which was induced by 2,2'-azobis (2-amidinopropane-hydrochloride) (AAPH), and measured as production of conjugated diene lipid hydroperoxides. Concentration as low as 5 and 10 microM were poorly effective in reducing lipid peroxidation. Melatonin at 30 to 500 microM caused short inhibition periods, increasing with, but not linearly related to concentration, with a concurrent net decrease of the propagation rate. The time course of melatonin oxidation, measured as loss of fluorescence, was studied during the AAPH-stimulated peroxidation of soybean PC liposomes, or whe…

The use of cultured hepatocytes to investigate the metabolism of drugs and mechanisms of drug hepatotoxicity.

2001

Hepatotoxins can be classified as intrinsic when they exert their effects on all individuals in a dose-dependent manner, and as idiosyncratic when their effects are the consequence of an abnormal metabolism of the drug by susceptible individuals (metabolic idiosyncrasy) or of an immune-mediated injury to hepatocytes (allergic hepatitis). Some xenobiotics are electrophilic, and others are biotransformed by the liver into highly reactive metabolites that are usually more toxic than the parent compound. This activation process is the key to many hepatotoxic phenomena. Mitochondria are a frequent target of hepatotoxic drugs, and the alteration of their function has immediate effects on the ene…

A Polyunsaturated Fatty Acid Diet Lowers Blood Pressure and Improves Antioxidant Status in Spontaneously Hypertensive Rats

2001

gamma-Linolenic acid [GLA, 18:3(n-6)], eicosapentaenoic acid [EPA, 20:5(n-3)] and docosahexaenoic acid [DHA, 22:6(n-3)] have been reported to prevent cardiovascular diseases. However, they are highly unsaturated and therefore more sensitive to oxidation damage. We investigated the effects of a diet rich in these polyunsaturated fatty acids (PUFA) on blood pressure, plasma and lipoprotein lipid concentrations, total antioxidant status, lipid peroxidation and platelet function in spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY). Five-week-old SHR and WKY rats were fed for 10 wk either a diet containing Isio 4 oil or a diet rich in GLA, EPA and DHA (5.65, 6.39 and…

Purification and Characterization of Acidic Glutathione S-Transferases (EC 2.5.1.18) from Rat Kidney

1988

Glutathione S-transferases (EC 2.5.1.18) (GSTs) are present in almost every mammalian tissue and catalyze the conjugation of glutathione (GSH) with different electrophilic substrates (Habig et al. 1974). In contrast to this deactivation function of GSTs, they also appear to be involved in the activation of certain chemicals, and particularly halogenated compounds, in either the liver or extra-hepatic tissues (even the kidney) to nephrotoxic and potentially nephrocarcin-ogenic products (Anders et al. 1987, Dekant et al. 1986, Elfarra and Anders 1984, Igwe 1986). These previous results confirm the necessity of a deeper insight into the GSH conjugation system of the kidney: firstly, because of…

Effects of carbamates as oxidative stressors on glutathione levels and lipid peroxidation in CHO-K1 cells

2006

Hepatitis C virus eradication by direct antiviral agents abates oxidative stress in patients with advanced liver fibrosis

2020

Background and aims: HCV eradication improves non-hepatic outcomes such as cardiovascular diseases, although without clearly defined mechanisms. In this study we aimed to assess whether improvement of carotid atherosclerosis may be linked to a reduction in systemic oxidative stress after viral clearance. Methods: We studied a retrospective cohort of 105 patients (age 62.4 ± 11.2 years; 62 men) with F3/F4 fibrosis, characterized by carotid ultrasonography at baseline and at sustained virologic response (SVR) follow-up. Levels of 8-iso-prostaglandin F2α (F2-isoprostanes) and other oxidative stress markers were measured on frozen sera. Association between change (denoted as Δ) in oxidative str…

Fibroblast Growth Factor 21 Limits Lipotoxicity by Promoting Hepatic Fatty Acid Activation in Mice on Methionine and Choline-Deficient Diets

2014

Background & Aims Nonalcoholic fatty liver disease is a common consequence of human and rodent obesity. Disruptions in lipid metabolism lead to accumulation of triglycerides and fatty acids, which can promote inflammation and fibrosis and lead to nonalcoholic steatohepatitis. Circulating levels of fibroblast growth factor (FGF)21 increase in patients with nonalcoholic fatty liver disease or nonalcoholic steatohepatitis; therefore, we assessed the role of FGF21 in the progression of murine fatty liver disease, independent of obesity, caused by methionine and choline deficiency. Methods C57BL/6 wild-type and FGF21-knockout (FGF21-KO) mice were placed on methionine- and choline-deficient (MCD)…

Allopurinol prevents cardiac and skeletal muscle damage in professional soccer players

2014

Xanthine oxidase (XO), a free radical-generating enzyme, is involved in tissue damage produced during exhaustive exercise. Our aim was to test whether allopurinol, a powerful inhibitor of XO, may be effective in preventing exercise-induced tissue damage in soccer players. Twelve soccer players were randomized into two experimental groups. One received allopurinol, before a match of the premier Spanish Football League, and the other placebo. Allopurinol prevented the exercise-induced increase in all the markers of skeletal muscle damage analyzed: creatine kinase, lactate dehydrogenase, aspartate aminotransferase, and myoglobin. Creatine kinase-MB isoenzyme and highly sensitive troponin T, sp…

F-2-isoprostanes: review of analytical methods

2006

International audience; F2-isoprostanes (F2-isoPs) represent a new family of biomarkers for oxidative stress generated by free radical attack of membrane-bounded arachidonic acid. Esterified F2-isoPs can be found in tissue or plasma lipids whereas the free form F2-isoPs, hydrolyzed by phospholipase, is mainly present in body fluids. The extent of systematic damage due to oxidative stress within the body can be assessed by the determination of plasma or urine F2-isoPs. The determination of F2-isoPs in clinical practice is not often used due to the complexity to extract the compounds from their biologic matrixes before the analysis step. In most of published protocols, extraction procedure is…

Allopurinol Protective Effect of Renal Ischemia by Downregulating TNF-α, IL-1β, and IL-6 Response

2016

Allopurinol is a well-known antioxidant that protects tissue against ischemia and reperfusion injury, blocking purine catabolism, and possibly reducing TNF-α and other cytokines. It also plays a significant role in reducing the inflammatory processes by inhibiting chemotaxis and other inflammatory mediators. The objective of this study was to define the role of allopurinol regarding kidney ischemic injury particularly as to its effect on inflammatory molecules such as TNF-α, IL-1β, and IL-6 response. One hundred and twenty five rats were subjected to warm renal ischemia. Five more animals were included as sham. Animal survival and plasma levels of lipid peroxidation, myeloperoxidase, lactat…