Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P30044 (antioxidant enzyme)
 8,037 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Impaired antioxidant defense mechanisms and oxidative stress are implicated in the pathogenesis of arsenic toxicity. Our study was designed to determine whether alpha-lipoic acid, which has been shown to have substantial antioxidant properties, when administered (70 mg/kg body weight) once daily for 60 days along with arsenic (100 ppm sodium arsenite mixed in drinking water) would prevent arsenic-induced changes in antioxidant defense system, superoxide dismutase (SOD-total SOD, Mn SOD, Cu/Zn SOD), catalase (CAT) and glutathione peroxidase (GSH-PX) in rat brain regions such as cortex, hypothalamus, striatum, cerebellum and hippocampus. The present study also examined the effect of alpha-lipoic acid over arsenic-induced oxidant production and lipid peroxidation level (LPO) in discrete brain regions of rats. The cortex, striatum and hippocampus showed greater decreases in GSH-Px enzyme activity than cerebellum and hypothalamus with arsenic exposure. Striatum had the greatest percentage of decreased activities of total SOD and Mn SOD, whereas cortex had the greatest percentage decrease in the activity of Cu/Zn SOD in arsenic-alone treated rats. Hypothalamus and cerebellum exhibited the lowest catalase activity among all tested regions in arsenic-only treated rats. Rate of dichlorofluorescin oxidation, an indication of reactive oxygen species and other intracellular oxidants production was increased with arsenic exposure in all brain regions studied. Cortex, hippocampus and striatum exhibited greater increase of LPO levels than cerebellum and hypothalamus. SOD, CAT, GSH-Px activities were upregulated in arsenic plus lipoic acid treated versus arsenic-only treated rats. Also, simultaneous lipoic acid treatment along with arsenic proved to be sufficient in reducing oxidant production and LPO level in all rat brain regions. Our results demonstrate that arsenic-induced deficits in antioxidant enzyme activities and increase in oxidant production and lipid peroxidation level in brain regions can be overcome through simultaneous treatment with lipoic acid.
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PMID:Brain regional responses in antioxidant system to alpha-lipoic acid in arsenic intoxicated rat. 1580 55

This study examined the ameliorative effect of a Du-zhong (Eucommia ulmoides Oliv.) cortex water extract (DzCw) on heme biosynthesis and erythrocyte antioxidant enzyme activities in lead (Pb)-administered rats. Male rats were divided into three groups: normal control group, Pb control group (Pb), and DzCw-administered Pb group (Pb + DzCw). The Pb (25 mg/kg of body weight) was administered orally once a week for 4 weeks, while the DzCw was administered orally at a dosage of 0.139 g of DzCw/kg of body weight/day. DzCw administration significantly lowered plasma Pb concentration compared with the Pb group. Furthermore, the blood hematocrit and hemoglobin levels were significantly higher in the Pb + DzCw group than in the Pb group. Although the blood and hepatic delta-aminolevulinic acid dehydratase (ALAD) activities were significantly lower in the Pb group compared with the normal control group, both ALAD activities was normalized with the administration of DzCw. The erythrocyte superoxide dismutase and catalase activities were significantly higher in the Pb group than in the normal control group, whereas the glutathione peroxidase activity and glutathione level were lowered by Pb administration compared with the normal group. However, the administration of DzCw was found to enhance the antioxidant defense system and significantly lower lipid peroxidation levels in erythrocytes compared with the Pb group. These results indicate that the DzCw administration alleviated the Pb-induced oxidative stress in the erythrocytes through elevating the blood and hepatic ALAD activity and enhancing the antioxidant enzyme activities.
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PMID:Du-zhong (Eucommia ulmoides Oliv.) cortex water extract alters heme biosynthesis and erythrocyte antioxidant defense system in lead-administered rats. 1585 15

Oxidative stress due to enhanced production of free radicals has been incriminated as one of the several mechanisms involved in arsenic-induced toxic effects in different organs. In the present study, ameliorative potential of certain amino acids like cysteine, methionine and vitamins like ascorbic acid and thiamine on some of the parameters indicative of oxidative stress in liver, kidney and blood and of hepatic and renal infliction was investigated in arsenic exposed rats. Rats were given 0 ppm (group I healthy controls) or 10 ppm arsenic in drinking water ad lib for a period of 12 weeks. During oral exposure to arsenic rats of different groups received daily oral dose of placebo, cysteine, methionine, ascorbic acid or thiamine at 25mg/kg body weight. After the end of the experimental period, animals were sacrificed under light anesthesia and blood, liver and kidney were collected. Samples were processed for estimation of arsenic, biochemical parameters indicative of oxidative stress and hepatic and renal function. Arsenic exposure resulted in significantly (P<0.05) higher accumulation of arsenic in blood, liver and kidney. It was associated with significant (P<0.05) rise in lipid peroxide level and decrease in superoxide dismutase and catalase activities in liver and kidneys. However, alterations in biochemical parameters did not reach statistical (P>0.05) significance. Treatment with vitamins and amino acids resulted in reversal of oxidative stress with significant (P<0.05) decline in tissue arsenic burden. All the treatment produced tissue specific changes in lipid peroxide level, antioxidant enzyme activities and tissue arsenic burden.
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PMID:Effect of cysteine, methionine, ascorbic acid and thiamine on arsenic-induced oxidative stress and biochemical alterations in rats. 1586 45

Caddisfly larvae of Hydropsyche exocellata were sampled from seven locations receiving increasing levels of urban and industrial waste water discharges along the Llobregat river system (NE Spain) during spring and summer 2003. Locations were selected to include aquatic communities in poor and good ecological state according to measured physicochemical water parameters and the analysis of benthic macroinvertebtrate communities. Whole body residues of selected metals (Fe, Al, Zn, Cu, Co, Ni, Pb, Cd) were determined in conjunction with antioxidant enzyme activities (superoxide dismutase, SOD; catalase, CAT; glutathione peroxidase activity of GST, GSTPX), a phase II enzyme (glutathione-S-transferase, GST) and lipid peroxide levels measured as thiobarbituric reactive species (TBARs) with the aim of investigating whether resident macroinvertebrate benthic species were responsive to changes in water quality. Caddisfly larvae inhabiting those rivers were exposed to increasing levels of metal pollution. Enhanced activities of two (CAT and GST) out of the four tested enzymes, coupled with increased levels of TBARs, indicated increasing levels of stress in the studied species towards downstream reaches or locations near industrial and urban areas. These results indicate that combination of chemical and biochemical responses can be used to assess and diagnose pollution in high stressed river ecosystems.
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PMID:Trace metal concentration, antioxidant enzyme activities and susceptibility to oxidative stress in the tricoptera larvae Hydropsyche exocellata from the Llobregat river basin (NE Spain). 1591 18

It is reported that the water extract of tea as well as tea polyphenols and tea pigments have strong antioxidant properties, which are considered as the major mechanism of the protective effects of tea on cancer and cardiovascular diseases. It has been shown that tea (including tea polyphenols and tea pigments) could induce the antioxidant enzyme activities, regulate phase I and II metabolic enzymes, inhibit the metabolic activation of carcinogens, reduce the formation of carcinogen DNA adducts, inhibit the expression and replication of oncogenes, directly affect the activity of transcription factors, and block the initiation of carcinogenesis, so as to eliminate and alleviate the damage to cellular communication caused by oxidative stress, and eventually prevent the abnormal proliferation of tumor cells. The mechanisms of the protective effects of tea on cardiovascular diseases are possibly related to its effects on the inhibition of lipid oxidation and quenching oxygen and hydroxy free radicals. It was demonstrated that tea pigments could inhibit the oxidation of LDL cholesterol and the adhesion of blood vessel endothelium cells, lower endothelin levels, enhance GSH-PX activities, prevent from blood coagulation and platelet aggregation, and facilitate fibrinogen dissolution, so as to prevent atherosclerosis of coronary arteries.
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PMID:[Studies on the antioxidant properties of tea]. 1595 73

The aim of this work was to evaluate the potential utility of several biochemical parameters as indicators of the toxic effects of cadmium in the freshwater clam Corbicula fluminea under two levels of oxygenation (normoxia 21 kPa and hypoxia 4 kPa). These variations in oxygenation are representative of the natural environments of bivalves living at the bottom of the water column, where hypoxic episodes may occur regularly. Cadmium accumulation, metallothionein synthesis, MXR protein induction, lipoperoxidation and antioxidant enzyme activities (catalase, glutathione reductase and total and selenium-dependent glutathione peroxidases) were assessed in the gills of C. fluminea in four experimental conditions: normoxia, hypoxia, normoxia with cadmium and hypoxia with cadmium ([Cd]=30 microg l(-1)) over a 14-day period. Behavioural reactions were also followed for the duration of the experiment by monitoring clam activity and valve movements. This study is a first report on biochemical responses under cadmium contamination and hypoxia and will enable us to determine better biomarkers for C. fluminea as they were measured simultaneously. In metal-exposed animals, we found an increasing accumulation of cadmium in the gills with time, and this was more severe in hypoxic conditions. Metallothionein synthesis occurred in contaminated clams and was precocious in hypoxic conditions. MXR protein induction appeared promising due to its quick and significant response to metal with a strong impact from hypoxic contamination. On the other hand, in our experimental conditions, antioxidant parameters did not show decisive responses to contamination and hypoxia, except glutathione peroxidases which decreased systematically with time in a cadmium-independent manner. Lipid peroxidation, expressed as malondialdehyde content, was not stimulated by normoxic contamination, as has been shown in other studies, but was stimulated under hypoxic cadmium contamination. Our study confirms the importance of a multi-biomarker approach in environmental studies as some are not appropriate to all organisms.
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PMID:Impact of cadmium contamination and oxygenation levels on biochemical responses in the Asiatic clam Corbicula fluminea. 1604 Jan 39

Catalase is a highly conserved heme-containing antioxidant enzyme known for its ability to degrade hydrogen peroxide into water and oxygen. In low concentrations of hydrogen peroxide, the enzyme also exhibits peroxidase activity. We report that mammalian catalase also possesses oxidase activity. This activity, which is detected in purified catalases, cell lysates, and intact cells, requires oxygen and utilizes electron donor substrates in the absence of hydrogen peroxide or any added cofactors. Using purified bovine catalase and 10-acetyl-3,7-dihydroxyphenoxazine as the substrate, the oxidase activity was found to be temperature-dependent and displays a pH optimum of 7-9. The Km for the substrate is 2.4 x 10(-4) m, and Vmax is 4.7 x 10(-5) m/s. Endogenous substrates, including the tryptophan precursor indole, the neurotransmitter precursor beta-phenylethylamine, and a variety of peroxidase and laccase substrates, as well as carcinogenic benzidines, were found to be oxidized by catalase or to inhibit this activity. Several dietary plant micronutrients that inhibit carcinogenesis, including indole-3-carbinol, indole-3-carboxaldehyde, ferulic acid, vanillic acid, and epigallocatechin-3-gallate, were effective inhibitors of the activity of catalase oxidase. Difference spectroscopy revealed that catalase oxidase/substrate interactions involve the heme-iron; the resulting spectra show time-dependent decreases in the ferric heme of the enzyme with corresponding increases in the formation of an oxyferryl intermediate, potentially reflecting a compound II-like intermediate. These data suggest a mechanism of oxidase activity involving the formation of an oxygen-bound, substrate-facilitated reductive intermediate. Our results describe a novel function for catalase potentially important in metabolism of endogenous substrates and in the action of carcinogens and chemopreventative agents.
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PMID:Characterization of the oxidase activity in mammalian catalase. 1607 30

Tritium ((3)H) may enter the environment from human activities, particularly at production, processing, or waste storage sites such as the Department of Energy's Savannah River Site, a former nuclear production facility in South Carolina. Understanding the dynamics and potential adverse effects of tritium in exposed organisms is critical to evaluating risks of tritium releases at such sites. Previous studies estimated the biological half-life of tritium in mice to be approximately 1.13 d; however, these laboratory studies were not conducted under environmentally realistic conditions. In this study, designed to be more representative of environmental exposure, mice were allowed to drink water containing tritium (activity about 300 Bq/ml) for a period of 2 wk. The induction of oxidative stress from tritium exposure was evaluated by comparing the activities of antioxidant enzymes (catalase, glutathione peroxidase, and superoxide dismutase) in exposed and control mice. From this experiment, the biological half-life of tritium was determined to be 2.26 +/- 0.04 d, almost double previous estimates. While positive controls (x-ray irradiated mice) showed responses in antioxidant enzyme activity, there was no indication of oxidative stress induction in mice exposed to tritium at this concentration.
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PMID:Biological half-life and oxidative stress effects in mice with low-level, oral exposure to tritium. 1626 91

This study was carried out to investigate effects of developmental Pb-exposure on antioxidant enzyme activities of mice brain. BALB dams were exposed to 600 p.p.m. of Pb-acetate in drinking water during pregnancy and lactation. Pb-exposure presented significant increase of plasma and brain Pb and 5-aminolevulinic acid (ALA) concentrations of weaned pups. In Pb-exposed 21-day-old pups, activities of superoxide dismutase, glutathione peroxidase (GSH-Px) and glutathione reductase (GSH-Re) decreased significantly in hypothalamus, corpora quadrigemina and corpus striatum compared with Na-exposed pups. Regarding 70-day-old pups, Pb-exposure had different effects on antioxidant enzymes of the three brain regions. The activities of GSH-Px and GSH-Re in corpora quadrigemina and GSH-Re in hypothalamus of Pb-exposure group did not decrease significantly. That meant that the lead employed might make occurrence of long-term effect on the antioxidant enzymes possible. The result also implied a correlation between ALA and oxidative stress in mice brain. Based on these results, it seemed that oxidative stress because of decreased antioxidant function, induced by significant accumulation of ALA, might be the main mechanism involved in mice brain neurotoxicity induced by developmental Pb-exposure.
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PMID:Oxidative stress in mouse brain exposed to lead. 1644 4

We studied the effects of high-light exposure (500 micromol m(-2) s(-1) of photosynthetic active radiation) on the cyanobacteria Nostoc spongiaeforme Agardh, a fresh-water alga, and Phormidium corium Agardh (Gomont), a marine alga, with respect to photosynthesis, pigments, sugar content, lipid peroxidation, fatty acids composition, antioxidant enzymes activity and DNA. It was seen that the ratio of variable fluorescence (Fv) to maximum fluorescence (Fm), which is indicative of photosynthetic efficiency, decreased because of the light treatment. The damage to photosynthesis occurred in the antenna system and the photosynthetic II reaction center. Photobleaching of photosynthetic pigments was also observed. High-light treatment also resulted in decreased sugar content, which was probably due to the effect on photosynthesis. Peroxidation of membrane lipids, indicating oxidative damage to lipids and a high level of unsaturation in the cell membrane, was also observed. The activity of antioxidant enzyme superoxide dismutase and ascorbate peroxidase was increased, probably as a result of oxidative damage observed in the form of lipid peroxidation. Quantitative decreases in phospholipid and glycolipid levels were also observed. The level of unsaturated fatty acids in total lipids and glycolipids remained unchanged in both species; however, the level of saturated fatty acids decreased, which slightly changed the ratio in favor of unsaturated fatty acids. Degradation of DNA was also observed in both species. There was a transient plateau 2-4 h after exposure to high-light treatment in the Fv/Fm ratio and in levels of phycobilisome pigments, sugars and antioxidant enzymes after an initial decrease 1 h after the treatment. These findings may indicate a period of partial adaptation to high light that is due to the efficiency of protective processes operational in the two species, which subsequently failed after a longer exposure duration of 4-6 h.
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PMID:High-light-induced changes on photosynthesis, pigments, sugars, lipids and antioxidant enzymes in freshwater (Nostoc spongiaeforme) and marine (Phormidium corium) cyanobacteria. 1646 27


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