In peroxisomes isolated from pea leaves (Pisum sativum L.) the production of superoxide free radicals (O(2) (-)) by xanthine and NADH was investigated. In peroxisomal membranes, 100 micromolar NADH induced the production of O(2) (-) radicals. In the soluble fractions of peroxisomes, no generation of O(2) (-) radicals was observed by incubation with either NADH or xanthine, although xanthine oxi...

Refractory peptic ulceration refers to ulcers which are slow to heal despite active treatment for at least three months. Oxygen-derived free radicals are cytotoxic and promote tissue injury. Twelve consecutive patients with refractory peptic ulceration (eight with duodenal ulcers and four with solitary pre-pyloric gastric ulcers) were treated using the radical scavengers allopurinol or dimethyl...

Inflammation is a complex localized response to foreign substances. In many inflammatory disorders there is excessive activation of phagocytes, production of O 2 , OH radicals as well as non-free radical species [H 2 O 2 ]. These free radicals are the main culprits in lipid peroxidation resulting in membrane destruction followed by production of mediators and chemotactic factors. Hence the agen...

The aim of this study was to investigate the roles of oxygen free radicals and mitochondrial signaling in semen disorders, in particular, how this induces low concentrations and reduced motility of sperm. Ejaculate samples were obtained from 120 young adult males (mean age, 28.7±5.3 years) with normal semen (n=30), oligospermia (n=30), asthenospermia (n=30) and oligoasthenozoospermia (n=30). Th...

A free radical is defined as any atom or molecule that contains unpaired electrons and has independent existence (hence, the term free). A dot is used to represent a free radical species. The abstraction or gain of one electron by a nonradical molecule may (or may not) convert it to a radical species. Free radicals can have positive, negative, or neutral charges [reactions (12.1.1) and (12.1.2)].

N-acetyl cysteine (NAC), as a nutritional supplement, is a greatly applied antioxidant in vivo and in vitro. NAC is a precursor of L-cysteine that results in glutathione elevation biosynthesis. It acts directly as a scavenger of free radicals, especially oxygen radicals. NAC is a powerful antioxidant. It is also recommended as a potential treatment option for different disorders resulted from g...

The processes of oxidation are intrinsic in the management of energy of all living organisms and are, therefore, kept under strict control by several cellular mechanisms (Halliwell and Gutteridge, 2007). However, reactive oxygen species (ROS), generated during metabolism, are very unstable and highly reactive, due to the presence of unpaired electrons, which include superoxide anion radicals, h...

1. Oxygen radicals in biological systems and the importance of iron Oxygen radicals can be either organic or inorganic. The organic radicals such as the peroxy (ROO') and alkoxy (RO') are those derived from complex molecules like the polyunsaturated fatty acids. The inorganic oxygen radicals are the superoxide radical (O,-*) and the hydroxyl radical (OH'). Formation of the highly reactive hydro...