Reactive oxygen species (ROS) are important mediators of the cytotoxicity induced by the direct reaction of ionising radiation (IR) with all critical cellular components, such as proteins, lipids, and nucleic acids. The derived oxidative damage may propagate in exposed tissues in a dose- and spatiotemporal dependent manner to other cell compartments, affecting intracellular signalling, and cell fate. To understand how cell damage is induced, we studied the oxidative events occurring immediately after cell irradiation by analysing the fate of IR-derived ROS, the intracellular oxidative damage, and the modification of redox environment accumulating in Chinese hamster ovary (CHO) within 1 h after cell irradiation (dose range 0-10 Gy).
View Article and Find Full Text PDFIn this work we investigated the genotoxicity of zinc oxide and titanium dioxide nanoparticles (ZnO NPs; TiO2 NPs) induced by oxidative stress on human colon carcinoma cells (Caco-2 cells). We measured free radical production in acellular conditions by Electron Paramagnetic Resonance technique and genotoxicity by micronucleus and Comet assays. Oxidative DNA damage was assessed by modified Comet assay and by measuring 8-oxodG steady state levels.
View Article and Find Full Text PDFAims: The biochemistry underlying the physiological, adaptive, and toxic effects of carbon monoxide (CO) is linked to its affinity for reduced transition metals. We investigated CO signaling in the vasculature, where hemoglobin (Hb), the CO most important metal-containing carrier is highly concentrated inside red blood cells (RBCs).
Results: By combining NMR, MS, and spectrophotometric techniques, we found that CO treatment of whole blood increases the concentration of reduced glutathione (GSH) in RBC cytosol, which is linked to a significant Hb deglutathionylation.
CO(2) changes the biochemistry of peroxynitrite basically in two ways: (i) nitrating species is the CO(3)(-) / ()NO(2) radical pair, and (ii) peroxynitrite diffusion distance is significantly reduced. For peroxynitrite generated extracellularly this last effect is particularly dramatic at low cell density because CO(3)(-) and ()NO(2) are short-lived and decay mostly in the extracellular space or at the cell surface/membrane. This study was aimed to distinguish between peroxynitrite-induced extra- and intracellular modifications of red blood cells (RBC).
View Article and Find Full Text PDFA complex antioxidant system is present in human saliva, with uric acid being the most concentrated component. Ascorbic acid, present at low concentrations in saliva, is actively secreted into the gastric lumen. We report that ascorbic acid added to human saliva at pH 2 was consumed within a few minutes, regenerating HNO(2), whereas uric acid was consumed relatively slowly in a nitrite-dependent manner.
View Article and Find Full Text PDFDietary inorganic nitrate is secreted in saliva and reduced to nitrite by bacterial flora. At the acidic pH of the stomach nitrite is present as nitrous acid in equilibrium with nitric oxide (*NO), and other nitrogen oxides with nitrating and nitrosating activity. *NO in the stomach exerts several beneficial effects, but nitrosating/nitrating species have been implicated as a possible cause of epithelial neoplasia at the gastroesophageal junction.
View Article and Find Full Text PDFThe reaction of *NO and NO2- with hemoglobin (Hb) is of pivotal importance to blood vessel function. Both species show at least two different reactions with Fe2+ Hb: one with deoxygenated Hb, in which the biological properties of *NO are preserved, and another with oxygenated hemoglobin (oxyHb), in which both species are oxidizes to NO3-. In this study we compared the oxidative reactions of *NO and NO2- and, in particular, the radical intermediates formed during transformation to NO3-.
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