Free radical can be defined as a molecule or molecular fragments containing unpaired electron in the outer orbital, which react with nearby molecules to get stability. There are two types of them in the body: oxygen free radicals and nitrogen free radicals. Our body has an antioxidant defense system which prevents accumulation of these radicals. There is a balance between free radical produc...

Nitrofurazone is shown to undergo an initial 1-electron (oxygen-sensitive) or 2- or more electron (oxygen-insensitive) reduction by partially purified nitroreductases from Escherichia coli. Nitrofurazone (50 micronM) is reduced by the oxygen-sensitive reductase to a nitro anion free radical as indicated by ESR and visible spectroscopy. The visible spectrum of the nitro anion free radical is cha...

It has been hypothesized that hyperthermia promotes oxygen-centered free radical formation in cells; however, to date there is no direct evidence of this heat-induced increase in oxygen free radical flux. Using electron paramagnetic resonance (EPR) spin trapping, we sought direct evidence for free radical generation during hyperthermia in intact, functioning cells. Rat intestinal epithelial cel...

Free Radicals and Ocular Disease p. 73 Active Oxygen Mechanisms of UV Inflammation p. 87 Oxygen-Free Radicals at Myocardial Level: Effects of Ischaemia and Reperfusion p. 99 Mechanisms of Atherosclerosis: Role of LDL Oxidation p. 113 Tissue Iron Overload and Mechanisms of Iron-Catalyzed Oxidative Injury p. 129 Free Radicals in the Pathophysiology of Pulmonary Injury and Disease p. 147 Lipid Per...

The potential role of oxygen free radicals in hCG-induced ovulation was investigated using the free radical scavenging enzymes superoxide dismutase (SOD) and/or catalase with the in-vitro perfused rabbit ovary preparation. SOD (25 \g=m\g/ml) and SOD + catalase (25 \g=m\g/ml)significantly reduced the % of large follicles that ovulated during perfusion (P < 0\m=.\005).Neither maturity nor degener...

Phenolphthalein, a widely used laxative, is the active ingredient in more than a dozen commercial nonprescription formulations. Fast-flow EPR studies of the reaction of phenolphthalein with horseradish peroxidase (HRP) and hydrogen peroxide permit the direct detection of two free radicals. One has EPR parameters characteristic of phenoxyl radicals. The other has a broad unresolved spectrum, pos...

Free oxygen radicals are an irrefutable component of life, underlying important biochemical and physiological phenomena in animals. Here it is shown that free oxygen radicals activate plasma membrane Ca(2+)- and K(+)-permeable conductances in Arabidopsis root cell protoplasts, mediating Ca(2+) influx and K(+) efflux, respectively. Free oxygen radicals generate increases in cytosolic Ca(2+) medi...

Astaxanthin is a coloring agent which is used as a feed additive in aquaculture nutrition. Recently, potential health benefits of astaxanthin have been discussed which may be partly related to its free radical scavenging and antioxidant properties. Our electron spin resonance (ESR) and spin trapping data suggest that synthetic astaxanthin is a potent free radical scavenger in terms of diphenylp...

It has been proposed that oxygen free radicals mediate damage that occurs during postischemic reperfusion. Recombinant human superoxide dismutase (r-h-SOD) has been shown to be effective at reducing reperfusion injury, but it is not known if this infused enzyme actually reduces oxygen free radical concentrations in the myocardial tissue. Electron paramagnetic resonance spectroscopy was used to ...

BACKGROUND Airway inflammation represents the basis of respiratory allergic disease and is generally associated with increased oxidative stress. As a consequence of successful treatment leading to hyposenzibilization and remission of symptoms, decrease of reactive oxygen formation is expected. MATERIAL/METHODS This preliminary study evaluates the production of oxygen free radicals in white bl...