Lipid peroxidation, free radical

O] = oxidizing moiety, e.g., hydrogen peroxide, free radical, lipid peroxide... 

In our attempts to determine the possible role of free radical lipid peroxidation in smoke induced injury, the levels of lipid peroxidation products - thiobarbituric acid reactants, mainly malondialdehyde - wereQmeasured in lung homogenates with or without prior incubation at 37 C for one hour, contrary to our expectation, the levels of thiobarbituric acid reactants were found to be decreased, rather than increased, in the lungs of cigarette-smoke-exposed rats (Table III). Such a depression effect, however, was observed only when animals were exposed to whole smoke, and not to the gaseous phase of smoke. 

Lipid peroxidation is a free radical-mediated, chain reaction resulting in the oxidative deterioration of polyunsaturated fatty acids (PUFAs) defined for this purpose as fatty acids that contain more than two double covalent carbon-carbon bonds. Singlet oxygen can produce lipid hydroperoxides in unsaturated lipids by non-radical processes (Pryor and Castle, 1984), but the reaction usually requires a radical mechanism (Porter, 1984). Polyunsaturated fatty acids are particularly susceptible to attack by free radicals. Lipid peroxidation is a complex process, and three distinct phases are recognized (a) initiation, (b) propagation and (c) termination (see Fig. 2.10). 

Esterbauer, H. Free Radicals, Lipid Peroxidation and Cancer McBrlen, D.C.H. and Slater, T.F. Eds. Academic Press, London, 1982, pp. 101-122. 

The Enzymatic Systems in the Regulation of Free Radical Lipid Peroxidation... 

There are three initiation mechanisms for the free radical lipid peroxidation in the living cells. At the first lipoperoxidation in the body can be induced by non-enzymatic mechanism. In this processes different physical factors such as ionizating irradiation or UV radiation as well as action of some chemical toxicants including air pollutants, pesticides and herbicides from food and drinking water may act as a initiating factors. 

V.Z.Lankin, Lipid peroxides and atherosclerosis. Hypothesis the role of cholesterol and free radical lipid peroxidation in altering cell membrane properties during hyprecholesterolemia and atherosclerosis, Kardiologiia (Cardiology) 20 (1980) 42-48. [Article in Russian]... 

Slater, T. F. In Free Radicals, Lipid Peroxidation and Cancer (McBrien, D. C. H. ... 

Parkes and co-workers have also conducted H NMR studies on s5movial fluid from patients with rheumatoid arthritis. Tbe nature of the nontransferrin-bound iron in the synovial fluid of patients with inflammatory joint disease was investigated. Transferrin is an iron ion transport protein. In these patients the synovial fluid contains non-transferrin-bound iron which appears to be in low-molecular-mass, redox-active complexes of unknown type. This form of iron has the adverse effect of stimulating free-radical lipid peroxidations involving oxygen. 500 MHz spin-echo H NMR spectroscopy was used to show that the incubation of patient synovial fluid with the powerful Fe(III)... 

Influx of Free Radicals, Lipid Peroxidation, ATP Depletion... 

Ability to trap hydroxyl free radicals, lipid peroxides and free radicals... 

Tappel, A.L. Free-radical lipid peroxidation damage and its inhibition by vitamin E and selenium. Fed. Proc. 24, 73-78 (1965)... 

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