The radical anion of dioxygen superoxide (O2.-) is a physiological free radical formed in various enzymatic processes. On the one hand superoxide is a precursor of reactive oxygen and nitrogen species (hydroxyl radicals, peroxy radicals, hydrogen peroxide, peroxynitrite, etc.), -the initiators of cellular damage; on the other hand it is a signaling molecule regulating numerous physiological pro...

1. Superoxide and hydrogen peroxide are formed by activated phagocytes and react together in the presence of iron salts to form the hydroxyl radical, which attacks hyaluronic acid. Ascorbic acid also interacts with hydrogen peroxide and iron salts to form hydroxyl radical in a reaction independent of superoxide. Since iron salts, ascorbate and activated phagocytes are present in the rheumatoid ...

Oxygen-centered radicals, particularly the hydroxyl and superoxide radicals, have been postulated in many biochemical reactions and have been implicated in many adverse reactions in vivo. This article begins with a review of spin-trapping detection of oxygen-centered radicals in vitro and concludes with a presentation of our approach to the detection of the hydroxyl radicals in models of acute ...

An ultrasonic-assisted extraction of Chlorella pyrenoidosa polysaccharides (CPP) was carried out using different concentrations of ethanol for precipitation, and named as CPP60, CPP70 and CPP85, respectively. The monosaccharide composition of each polysaccharide (CPP) was determined using gas chromatography (GC) and the antioxidant activity of each was investigated via the reducing power and sc...

Phagocytosis of quartz particles by rabbit alveolar macrophages and monocytes and human granulocytes and monocytes was accompanied by stimulation of substrate free reduction of nitroblue tetrazolium to formazan. This reflects activation of an oxygen dependent bactericidal system of phagocytes and total (exogenic and endogenic) generation of active oxygen species. Low fibrogenic and cytotoxic al...

It has been more than 25 years since it was first reported that nifurtimox and benznidazole promote superoxide production in trypanosomes. However, there has been no direct evidence of an association between the drug-induced free radicals and trypanocidal activity. Here, we identify a superoxide dismutase required to protect Trypanosoma brucei from drug-generated superoxide.

Iron bound to certain chelators is known to promote the conversion of superoxide radicals (O2-) to hydroxyl radicals (HO.) by the superoxide-driven Fenton reaction. The production of HO. by various iron chelates was studied using the reaction of dimethyl sulfoxide and HO. to produce methane sulphinic acid. Methane sulphinic acid was quantified by use of a simple colorimetric assay and used to d...

High performance liquid chromatography with TSK 5000 PW or TSK 6000 PW size exclusion columns combined with a 125I labelled hyaluronic acid binding protein assay was used to study the effects of oxygen derived free radicals on synovial fluid hyaluronate. A continuous flux of free radicals was generated by the xanthine oxidase/hypoxanthine system. When the free radical flux was generated with xa...