Peter Moldéus

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The oxidation of 2′,7′-dichlorofluorescin (DCFH) to a fluorescent product is currently used to evaluate oxidant stress in cells. However, there is considerable uncertainty as to the enzymatic and nonenzymatic pathways that may result in DCFH oxidation. Iron/hydrogen peroxide-induced DCFH oxidation was inhibited by catalase or by the hydroxyl radical(More)
N-Acetyl-p-benzoquinone imine (NAPQI), a reactive metabolite of acetaminophen, rapidly reacts at physiological pH with glutathione (GSH) forming an acetaminophen-glutathione conjugate and stoichiometric amounts of acetaminophen and glutathione disulfide (GSSG). The same reaction products are formed in isolated hepatocytes incubated with NAPQI. In(More)
N-acetylcysteine (NAC) is a thiol-containing compound which nonenzymatically interacts and detoxifies reactive electrophiles and free radicals. NAC was shown to effectively protect human bronchial fibroblasts against the toxic effects of tobacco smoke condensates and the isolated perfused lung against the glutathione (GSH)-depleting effect of tobacco smoke.(More)
In the present study freshly isolated rat hepatocytes treated with the glutathione reductase inhibitor BCNU (1,3-bis(2-chloroethyl)-1-nitrosourea) were used to investigate the metabolism of tert-butyl hydroperoxide and of hydrogen peroxide formed in different intracellular compartments. Glycolate, benzylamine and hexobarbital were used to stimulate H2O2(More)
Exposure of human umbilical vein endothelial cells to oxidants such as hydrogen peroxide, tertbutyl hydroperoxide and diamide has been shown to induce oxidant-specific S-thiolation of cellular proteins. In this study one of the main S-thiolated proteins in hydrogen-peroxide-treated cells was identified as the glycolytic enzyme glyceraldehyde-3-phosphate(More)
The relationship between the metabolism and the cytotoxic effects of the alkyl esters of p-hydroxybenzoic acid (parabens) has been studied in freshly isolated rat hepatocytes. Incubation of hepatocytes with propyl-paraben (0.5 to 2.0 mM) elicited a concentration- and time-dependent cell death that was enhanced when enzymatic hydrolysis of propyl-paraben to(More)
In order to clarify the role of oxidative processes in cytotoxicity we have studied the metabolism and toxicity of 2-methyl-1,4-naphthoquinone (menadione) and its 2,3 dimethyl (DMNQ) and 2,3 diethyl (DENQ) analogs in isolated rat hepatocytes. The two analogs, unlike menadione, cannot alkylate nucleophiles directly and were considerably less toxic than(More)
A series of simple methodologies for the determination of the redox status of low molecular weight and protein thiols in biological systems is described. Based centrally upon the use of monobromobimane, we describe a standard in situ derivatisation procedure simultaneously resulting in maximal recovery of both free, reduced low molecular weight and(More)