The effect of the selenium-containing compounds selenomethionine, selenocystine and ebselen [2-phenyl-1,2-benzisoselenazol-3(2H)-one] on the oxidation of dihydrorhodamine 123 caused by peroxynitrite and on the nitration of 4-hydroxyphenylacetate by peroxynitrite was studied in comparison with their sulphur analogues methionine, cystine and ebsulfur [2-phenyl-1,2-benzisothiazol-3(2H)-one]. The s...

Oxidation of dihydrorhodamine 123 (DHR) to rhodamine 123 (RH) by oxoperoxonitrite (ONOO(-)), formed through recombination of NO and O(2)(·-) radicals resulting from thermal decomposition of 3-morpholinosydnonimine (SIN-1) in buffered aerated aqueous solution at pH 7.6, represents a kinetic model system of the reactivity of NO and O(2)(·-) in biochemical systems. A magnetic-field effect (MFE) on...

Peroxynitrite (ONOO(((-)))/ONOOH) is expected in vivo to react predominantly with CO(2), thereby yielding NO(2)(.) and CO(3) radicals. We studied the inhibitory effects of ascorbate on both NADH and dihydrorhodamine 123 (DHR) oxidation by peroxynitrite generated in situ from 3-morpholinosydnonimine N-ethylcarbamide (SIN-1). SIN-1 (150 micrometer)-mediated oxidation of NADH (200 micrometer) was ...

Upon activation, neutrophils release reactive oxygen species that are believed to contribute to the widespread manifestation of preeclampsia. Neutrophils have an NADPH oxidase enzyme that catalyzes the production of reactive oxygen species. Little is known about the manifestations of the activated response and the upstream signaling pathways that regulate this process in preeclampsia. It is hyp...

Increasing evidence suggests that glutamate neurotoxicity is partly mediated by reactive oxygen species, formed as a consequence of several processes, including arachidonic acid metabolism and nitric oxide production. Here we used an oxidation-sensitive indicator, dihydrorhodamine 123, in combination with confocal microscopy, to examine the hypothesis that electron transport by neuronal mitocho...

Death of oligodendrocyte (OL) precursors can be triggered in vitro by cystine deprivation, a form of oxidative stress that involves depletion of intracellular glutathione. We report here that OLs demonstrate maturation-dependent differences in survival when subjected to free radical-mediated injury induced by glutathione depletion. Using immunopanning to isolate rat preoligodendrocytes (preOLs)...

A tissue-equivalent three-dimensional dosimeter is being developed to verify dose distributions for radiotherapy. Recently, we have reported a nanocomposite fluorescent gel (NC-RFG) that enables readout by the fluorometry, which more sensitive than absorption method in principle. However, irradiating an excitation light information also produces dyes and not negligible low-dose irradiation rang...