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The copolymers of N-methyl-2-azanorbornene-5 (MAN), N-benzyl-2-azanorbornene-5 (BAN), N-allyl-2- azanorbornene-5 (AAN) and N-(2-azanorbornene-5)methylacetate (MAAN) with N-vinylpyrrolidone (VP) have been obtained by free radical polymerization. New copolymers were evaluated for their antioxidant properties in lipid peroxidation induced by iron/ascorbate and in erythrocyte hemolysis by H2O2. The copolymer of BAN-VP has found to inhibit lipid peroxidation in liver homogenate. [ABSTRACT FROM AUTHOR]

Malonic dialdehyde (MDA) is a product of lipid peroxidation, its accumulation reflects the degree of oxidative stress in an organism. Assessment of the MDA level is used to reveal pathologic processes in an organism. It is difficult to assess the MDA level in blood, plasma and serum using traditional approaches. The paper proposes the method based on the derivative spectrophotometry, which allows high resolution and ensures exact determination of the location of the optical density maximum for a sample under test. The analyzer implementing the chosen analysis method is presented here, together with its technical specifications. [ABSTRACT FROM AUTHOR]

Membrane fouling due to foulants existing in the membrane feed water is an inevitable problem for ultrafiltration (UF) applied to water treatment. A bench-scale study was undertaken to evaluate the anti-fouling effect of different oxidants preoxidation on the dead-end, constant flux UF of surface water. Furthermore, the mechanisms of membrane fouling by natural organic matter (NOM) were examined. The concept of UMFI (unified membrane fouling index) was applied to assess hydraulically reversible and irreversible fouling potential of UF membrane in the bench-scale fouling studies. It was found that preoxidation greatly impacted the membrane fouling potential, which might be the result of changes of NOM characteristics. The transmembrane pressure (TMP) increased slightly and slowly with increasing dosage. The membrane fouled by preoxidation water was more amenable to chlorine-induced permeability recovery, but it was contrary for hydraulically irreversible fouling. Therefore, preoxidation is a promising pretreatment method for UF systems, and needed further determining. [ABSTRACT FROM AUTHOR]

We studied mathematical modeling of lipid peroxidation using a biochemical model system of iron (II)-ascorbate-dependent lipid peroxidation of rat hepatocyte mitochondrial fractions. We found that antioxidants extracted from plants demonstrate a high intensity of peroxidation inhibition. We simplified the system of differential equations that describes the kinetics of the mathematical model to a first order equation, which can be solved analytically. Moreover, we endeavor to algorithmically and heuristically recreate the processes and construct an environment that closely resembles the corresponding natural system. Our results demonstrate that it is possible to theoretically predict both the kinetics of oxidation and the intensity of inhibition without resorting to analytical and biochemical research, which is important for cost-effective discovery and development of medical agents with antioxidant action from the medicinal plants. [ABSTRACT FROM AUTHOR]

Introduction: Despite the cardiovascular benefits provided by polyunsaturated fatty acids (PUFA), there has been concern that these fatty acids exhibit the highest sensitiveness to peroxidation, which in turn could enhance production of reactive oxygen species. Here, we investigated the effects of different amounts of fish oil on oxidative status in red blood cells (RBC) from mice fed a high fat diet. Methods: C57BL/6 male mice were divided into six groups based on the diet offered; the control group was fed with a standard diet (10% lipids) and the others groups were fed with isoenergetic high fat diets (50% lipids) containing 0%, 10%, 20%, 30%, or 40% of fish oil. The high fat diets were composed of a mixture of lard and fish oil, with a gradual replacement of lard by fish oil. At the end of the experimental period (12 weeks), the animals were anaesthetized with intraperitoneal sodium pentobarbital (0.42 mg/g). Blood samples obtained by cardiac puncture were collected into a tube containing heparin and RBC were isolated by centrifugation. Oxidative damage in RBC was evaluated by determination of carbonyl groups and by the concentration of malondialdehyde (MDA). The activity of catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD) enzymes was analysed to evaluate the antioxidant status. The experimental protocols were approved by the local Ethics Committee (CEUA/033/2011). Comparisons among groups were done by one-way ANOVA followed by a Holm-Sidak post-hoc test. Significance level was set at 5%. Results: Table 1 shows the results of the oxidative stress parameters. Diets absent (F0) or with high concentrations of fish oil (F20, F30, F40) induced an increased RBC lipid peroxidation than standard chow diet. F0 mice also showed an increased protein oxidative damage, assessed by the quantification of carbonyl groups, compared to control, F20, F30, and F40 mice. No significant difference in protein oxidation was observed among none of the fish-oil fed mice. The antioxidant enzyme analysis showed that SOD activity in RBC from F0 and F10 groups was decreased compared to control group. The activity of the other antioxidant enzymes, CAT and GPx, did not differ among groups, except for a reduction in GPx levels from the F40 group compared to the F20 group. Conclusion: Lipid peroxidation of RBC rises linearly with increasing amounts of fish oil in the diet, however this increased susceptibility was not reflected in protein damage. The use of antioxidant products during dietary fish oil supplementation could be an alternative to ensure that their consumption does not result in detrimental secondary effects. Table 1. Oxidative stress parameters. Where applicable, the authors confirm that the experiments described here conform with The Physiological Society ethical requirements. [ABSTRACT FROM AUTHOR]

Cadmium performs its effect on living organisms by accumulating in various tissues and effects tissue antioxidant enzyme systems. The testes are critical target organ following cadmium exposure. The present study was planned to determine the possible protective roles of selenium and +(-) catechin against the toxic effects of cadmium. The study has been performed in Wistar Albino rats which divided into four groups as control, cadmium, cadmium+selenium and cadmium+ catechin received groups. Each experimental group consisted of ten rats. The experimental group rats have received cadmium sulphate, sodium selenite and +(-) catechin via there drinking water for thirty days. Cadmium concentration, lipid peroxidation and glutathione were measured in the homogenate of testes and blood. As a result of the study it may be said that: The cadmium accumulates in testes and its concentration increases in blood and possibly selenium administration is helpful against cadmium but not +(-)catechin. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]