The nitroxyl anion (NO-) is a highly reactive molecule that may be involved in pathophysiological actions associated with increased formation of reactive nitrogen oxide species. Angeli's salt (Na2N2O3; AS) is a NO- donor that has been shown to exert marked cytotoxicity. However, its decomposition intermediates have not been well characterized. In this study, the chemical reactivity of AS was ex...

BACKGROUND The interaction of circulating microparticles (MPs) with immune cells in systemic lupus erythematosus (SLE) is sparsely investigated. We examined the ability of MPs from SLE patients to induce production of reactive oxygen species (ROS) and degranulation of polymorphonuclear leukocytes (PMNs). METHODS Plasma MPs, leukocytes and sera isolated from 20 SLE patients and 10 healthy cont...

Cr(VI) genotoxicity is caused by products of its reductive metabolism inside the cells. Reactive oxygen species (ROS) and Cr(V,IV) intermediates are potential sources of oxidative damage by Cr(VI). Here, we investigated seven fluorescent probes for the detection of ROS and non-ROS oxidants in Cr(VI) reactions with its main reducers. We found that Cr(V)-skipping metabolism of Cr(VI) by ascorbate...

The oxidative burst is frequently evaluated by the conversion of dihydrorhodamine 123 (DHR) to rhodamine 123 (R123) and hydroethidium (HE) to ethidium with the use of flow cytometry (FCM). Added R123 accumulates in mitochondria, but during phagocytosis R123 originating from DHR has been observed in neutrophil granules. The present study was designed to identify the site of reactive oxygen speci...

S-Nitrosothiols (RSNO) occur in vivo and have been proposed as nitric oxide (.NO) storage and transport biomolecules. Still, the biochemical mechanisms by which RSNO release .NO in biological systems are not well defined, and in particular, the interactions between reactive oxygen species and RSNO have not been studied. In this work, we show that xanthine oxidase (XO), in the presence of purine...

Chronic granulomatous disease (CGD) is characterized by recurrent infections, and is usually associated with a complete inability of phagocytic cells to generate superoxide anion (O2-). Rarely, variant forms of CGD have been reported in which there is reduced, but detectable, O2- production by phagocytic cells. We describe three adult males in two kindreds with a unique form of X-linked cytochr...

Malignant mesothelioma (MMe) is a highly aggressive, lethal tumour requiring the development of more effective therapies. The green tea polyphenol epigallocathechin-3-gallate (EGCG) inhibits the growth of many types of cancer cells. We found that EGCG is selectively cytotoxic to MMe cells with respect to normal mesothelial cells. MMe cell viability was inhibited by predominant induction of apop...

Carcinogenesis is a multistep process that is frequently associated with p53 inactivation. The class 1 carcinogen cadmium (Cd(2+)) causes renal cancer and is known to inactivate p53. G(2)/mitosis (M) arrest contributes to stabilization of p53-deficient mutated cells, but its role and regulation in Cd(2+)-exposed p53-deficient renal cells are unknown. In p53-inactivated kidney proximal tubule (P...

BACKGROUND Failure to generate phagocyte-derived superoxide and related reactive oxygen intermediates (ROIs) is the major defect in chronic granulomatous disease, causing recurrent infections and granulomatous complications. Chronic granulomatous disease is caused by missense, nonsense, frameshift, splice, or deletion mutations in the genes for p22(phox), p40(phox), p47(phox), p67(phox) (autoso...

Tumor necrosis factor-alpha (TNF-alpha) causes oxidative stress and apoptosis in a variety of cell types. Heme oxygenase (HO) degrades heme to bilirubin, an antioxidant, and carbon monoxide (CO), a cell cycle modulator, and a vasodilator. Newborn pig cerebral microvascular endothelial cells (CMVEC) highly express constitutive HO-2. We investigated the role of HO-2 in protection against TNF-alph...