Plasma free radicals

G. Scorza, D. Pietraforte, M. Minetti, Role of Ascorbate and Protein Thiols in the Release of Nitric Oxide from 5-Nitroso-Albumin and 5-Nitroso-Glutathione in Human Plasma , Free Radical Biol. Med. 1997, 22,633-642. 

Polidori, M.C., Stahl, W., Eichler, O., Niestroj, I., and Sies, H. 2001. Profiles of antioxidants in human plasma. Free Radic. Biol. Med 30, 456 462. 

L8. Lee, A., Thurnham, D. I., and Chopra, M., Consumption of tomato products with olive oil but not sunflower oil increases the antioxidant activity of plasma. Free Radic. Biol. Med. 29,1051-1055 (2000). 

I 13 Aejmelaeus RT, Holm P Kaukine U, etal, Age-related changes in the peroxyl radical scavenging capacity of human plasma. Free Radic Biol Med 1997 23 69-75,... 

Morand, C., Manach, C., Crespy, V., and Remesy, C., Quercetin 3-O-P-glucoside is better absorbed than other quercetin forms and is not present in rat plasma, Free Radic. Res., 33, 667, 2000. 

Holloway DE, Yang M, Paganga G, Rice-Evans CA, Bramley PM. Isomerization of dietary lycopene during assimilation and transport in plasma. Free Radic Res 2000 32 93-102. 

Park, Y.K. et al.. Daily grape juice consumption reduces oxidative DNA damage and plasma free radical levels in healthy Koreans, Res., 529, 77,2003. 

Griffiths, W.J., Crick, P.J., Wang, Y., Ogundare, M., Tuschl, K., Morris, A.A., Bigger, B.W. and Clayton, P.T. (2013) Analytical strategies for characterization of oxysterol lipidomes Liver X receptor ligands in plasma. Free Radic. Biol. Med. 59, 69-84. 

The reaction mechanisms of plasma polymerization processes are not understood in detail. Poll et al [34] (figure C2.13.6) proposed a possible generic reaction sequence. Plasma-initiated polymerization can lead to the polymerization of a suitable monomer directly at the surface. The reaction is probably triggered by collisions of energetic ions or electrons, energetic photons or interactions of metastables or free radicals produced in the plasma with the surface. Activation processes in the plasma and the film fonnation at the surface may also result in the fonnation of non-reactive products. 

At 70—140°C, peroxide is vaporised. Peroxide vapor has been reported to rapidly inactivate pathogenic bacteria, yeast, and bacterial spores in very low concentrations (133). Experiments using peroxide vapor for space decontamination of rooms and biologic safety cabinets hold promise (134). The use of peroxide vapor and a plasma generated by radio frequency energy releasing free radicals, ions, excited atoms, and excited molecules in a sterilising chamber has been patented (135). 

Gas plasma treatment operates at low pressure and relatively low temperature. While the corona treatment is applicable to substrates in sheet or film form, the gas plasma process can treat objects of virtually any shape. The gases most widely used to generate plasma by free-radical reactions include air, argon, helium, nitrogen, and oxygen. All these, with the exception of oxygen. 

Flames are also plasmas, characterized by electron densities of about 10 /cm and electron energies of about 0.5 eV. Many excited species are present in the flame, namely free radicals, ions, excited atoms and molecules, and electrons [43]. Excited species that have been observed include O, OH, NH, NO, and CH [44]. 

Although iron deficiency is a common problem, about 10% of the population are genetically at risk of iron overload (hemochromatosis), and elemental iron can lead to nonen2ymic generation of free radicals. Absorption of iron is stricdy regulated. Inorganic iron is accumulated in intestinal mucosal cells bound to an intracellular protein, ferritin. Once the ferritin in the cell is saturated with iron, no more can enter. Iron can only leave the mucosal cell if there is transferrin in plasma to bind to. Once transferrin is saturated with iron, any that has accumulated in the mucosal cells will be lost when the cells are shed. As a result of this mucosal barrier, only about 10% of dietary iron is normally absorbed and only 1-5% from many plant foods. 

The main function of vitamin E is as a chain-breaking, free radical trapping antioxidant in cell membranes and plasma lipoproteins. It reacts with the lipid peroxide radicals formed by peroxidation of polyunsaturated fatty acids before they can establish a chain reaction. The tocopheroxyl free radical product is relatively unreactive and ultimately forms nonradical compounds. Commonly, the tocopheroxyl radical is... 

Attention has been given to the possibility that some of the above motor effects may arise from a metabolite of levodopa. The prime suspect is OMD which has a half-life of some 20 hours and reaches plasma concentrations three- to fourfold those of dopa. Suggestions that it may compete with dopa for entry across the blood-brain barrier or act as a partial agonist (effective antagonist) have not been substantiated experimentally although it does reduce DA release from rat striatal slices. Also if free radical production through deamination of DA is neurotoxic (see below) then this would be increased by levodopa. 

LOTiTO s B, FRAGA c G (1998) (+)-Catechin prevents human plasma oxidation, Free Radical Biology and Medicine, 24, 435-41. 

Dianzani, M.U., Paradisi, L., Barrera, G., Rossi, M.A. and Parola, M. (1989). The action of 4-hydroxynonenal on the plasma membrane enzymes from rat hepatocytes. In Free Radicals, Metal Ions and Biopolymers (eds. P.C. Neaumont, D.J. Deeble, B.J. Parsons and C. Rice-Evans) pp. 329-346. RicheUeu Press, London. 

Ungemach, F.R. (1985). Plasma membrane damage of hepato-cytes following lipid peroxidation involvement of phospholipase A2. In Free Radicals in Liver Injury (eds. G. Poli, K.H. Cheeseman, M.U. Dianzani and T.F. Slater) pp. 127-134. IRL Press, Oxford. 

Ascorbate has multiple antioxidant capacities and may be the most important water-soluble defence against free-radical damage in human plasma. At millimolar concentrations, ascorbate scavenges O2, OH and HOCl (Blake et al., 1983). The latter reaction protects plasma lipids against degradation by activated PMNs. 

Pippenger, C.E., Meng, X., Stolfi, V, McGonagle, B. and Fazio, V.W. (1991). Free radical scavenging activities and trace element concentrations in erythrocytes and plasma of adult patients with inflammatory bowel disease. In Inflammatory Bowel Diseases. Progress in Basic Research and Clinical Implications (eds. H. Gocbell, K. Ewe, H. Malchow and Ch. Koelbel) p. 33. Kluwer Academic Publishers, Lancaster. 

Collier et al. (1990) extended their studies relating to oxidative stress and diabetes by demonstrating that the levels of several free-radical scavengers (red cell superoxide dismutase, plasma thiols) were significantly reduced in 22 type 2 diabetic patients (mean age 53 years) in comparison with 15 control subjects (mean age 51 years). No significant diflFerences in red cell lysate thiols or... 

Essential hypertension, whose prevalence is increased nearly two-fold in the diabetic population, may be another source of free-radical activity. The vascular lesions of hypertension can be produced by free-radical reactions (Selwign, 1983). In the recent Kuopio Ischaemic Heart Risk Factor Study in Finnish men, a marked elevation of blood pressure was associated with low levels of both plasma ascorbate and serum selenium (Salonen etal., 1988). A few studies report a hypotensive effect of supplementary ascorbate in patients with hypertension, but the actual changes in both systolic and diastolic pressure after ascorbate were not statistically significant in comparison with placebo (Trout, 1991). 

Thompson, S. and Smith, M.T. (1985). Measurement of the diene conjugated from of linoleic acid in plasma by high performance liquid chromatography. A questionable non-invasive assay of free radical activity. Chem. Biol. Interactions 55, 357-366. 

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