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)

Cyclophosphamide causes lung injury in rats through its ability to generate free radicals with subsequent endothelial and epithelial cell damage. In order to observe the protective effects of a potent anti-inflammatory antioxidant, curcumin (diferuloyl methane) on cyclophosphamide-induced early lung injury, healthy, pathogen free male Wistar rats were exposed to 20 mg/100 g body weight of cyclophosphamide, intraperitoneally as a single injection. Prior to cyclophosphamide intoxication oral administration of curcumin was performed daily for 7 days. At various time intervals (2, 3, 5 and 7 days post insult) serum and lung samples were analyzed for angiotensin converting enzyme, lipid peroxidation, reduced glutathione and ascorbic acid. Bronchoalveolar lavage fluid was analyzed for biochemical constituents. The lavage cells were examined for lipid peroxidation and glutathione content. Excised lungs were analyzed for antioxidant enzyme levels. Biochemical analyses revealed time course increases in lavage fluid total protein, albumin, angiotensin converting enzyme (ACE), lactate dehydrogenase, N-acetyl-beta-D-glucosaminidase, alkaline phosphatase, acid phosphatase, lipid peroxide levels and decreased levels of glutathione (GSH) and ascorbic acid 2, 3, 5 and 7 days after cyclophosphamide intoxication. Increased levels of lipid peroxidation and decreased levels of glutathione and ascorbic acid were seen in serum, lung tissue and lavage cells of cyclophosphamide groups. Serum angiotensin converting enzyme activity increased which coincided with the decrease in lung tissue levels. Activities of antioxidant enzymes were reduced with time in the lungs of cyclophosphamide groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Modulation of cyclophosphamide-induced early lung injury by curcumin, an anti-inflammatory antioxidant. 775 45

Reactive oxygen species have been implicated in neuronal injury associated with various neuropathological disorders. However, little is known regarding the relationship between antioxidant enzyme capacity and resultant toxicity. The antioxidant pathways of primary cerebrocortical cultures were directly examined using a novel technique that measures pentose phosphate pathway (PPP) activity, which is enzymatically coupled to glutathione peroxidase (GPx) detoxification of hydrogen peroxide (H2O2). PPP activity was quantified from data obtained by gas chromatography/mass spectrometry analysis of released labeled lactate following metabolic degradation of [1,6-(13)C2, 6,6-(2)H2] glucose by cerebrocortical cultures. The antioxidant capacity of these cultures was systematically evaluated using H2O2, and the resultant toxicity was quantified by lactate dehydrogenase release. Exposure of primary mixed and purified astrocytic cultures to H2O2 caused stimulation of PPP activity in a concentration-dependent fashion from 0.25 to 22.2% and from 6.9 to 66.7% of glucose metabolized to lactate through the PPP, respectively. In the mixed cultures, chelation of iron before H2O2 exposure was protective and resulted in a correlation between PPP saturation and toxicity. Conversely, addition of iron, inhibition of GPx, or depletion of glutathione decreased H2O2-induced PPP stimulation and increased toxicity. These results implicate the Fenton reaction, reflect the pivotal role of GPx in H2O2 detoxification, and contribute to our understanding of the etiological role of free radicals in neuropathological conditions.
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PMID:Assessment of the role of the glutathione and pentose phosphate pathways in the protection of primary cerebrocortical cultures from oxidative stress. 863 55

We compared oxidant-induced intracellular adenine nucleotide catabolism and cell membrane injury in 4 different human cell types. Responses to oxidant exposure were correlated with endogenous antioxidant enzyme activities in these cells. Blood monocytes, amniotic fibroblasts, umbilical vein endothelial cells in primary culture, and transformed bronchial epithelial cells (BEAS 2B) were exposed to 0.1-5 mM hydrogen peroxide (H2O2) for 4 h. Some experiments were conducted in cells pretreated with 3-amino 1:2,4-triazole (ATZ) to inactivate catalase or with 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) to inactivate glutathione (GSH) reductase. Depletion of adenine nucleotides and accumulation of their catabolic products (hypoxanthine, xanthine and uric acid) occurred to varying extent, monocytes being the most resistant. There was a mutual relationship between catalase and GSH reductase activities and maintenance of cellular adenine nucleotide levels during H2O2 exposure. GSH reductase inhibition rendered BEAS 2B cells susceptible to lytic injury by H2O2, assessed by release of lactate dehydrogenase and intact nucleotides into the medium, there was no correlation between these markers of such injury and endogenous antioxidant enzymes. We conclude that adenine nucleotide depletion and nucleotide catabolite accumulation relate closely with the antioxidant enzyme activities, whereas the lack of a similar correlation between the enzyme levels and markers of lytic cell injury suggest that intracellular antioxidant enzymes do not protect cells from membrane damage due to extracellular oxidants.
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PMID:Intracellular high energy metabolite depletion and cell membrane injury with antioxidant enzymes during oxidant exposure in vitro. 865 Jun 98

The effects of nitric oxide (NO) produced by cardiac inducible NO synthase (iNOS) on myocardial injury after oxidative stress were examined: Interleukin-1 beta induced cultured rat neonatal cardiac myocytes to express iNOS. After induction of iNOS, L-arginine enhanced NO production in a concentration-dependent manner. Glutathione peroxidase (GPX) activity in myocytes was attenuated by elevated iNOS activity and by an NO donor, S-nitroso-N-acetyl-penicillamine (SNAP). Although NO production by iNOS did not induce myocardial injury, NO augmented release of lactate dehydrogenase from myocyte cultures after addition of H2O2 (0.1 mM, 1 h). Inhibition of iNOS with N omega-nitro-L-arginine methyl ester ameliorated the effects of NO-enhancing treatments on myocardial injury and GPX activity. SNAP augmented the myocardial injury induced by H2O2. Inhibition of GPX activity with antisense oligodeoxyribonucleotide for GPX mRNA increased myocardial injury by H2O2. Results suggest that the induction of cardiac iNOS promotes myocardial injury due to oxidative stress via inactivation of the intrinsic antioxidant enzyme, GPX.
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PMID:Inducible nitric oxide synthase augments injury elicited by oxidative stress in rat cardiac myocytes. 945 34

This work examines the hypothesis that beetle bioluminescent reactions may primarily have evolved to provide an auxiliary O2 detoxifying mechanism. The activities of antioxidant enzymes and of luciferase in the prothorax (bright) and abdomen (dim) of luminous larval Pyrearinus termitilluminans (Coleoptera: Elateridae) were measured after previous challenge with either hyperoxia, hypoxia, or the firefly luciferase inhibitor luciferin 6'-methyl ether (LME). Upon exposure to pure O2 for 72 h, the prothorax activities of total superoxide dismutase (SOD) and catalase were found to increase by 85% and 50%, respectively. Concomitantly, levels of luciferase and luciferin increased 80% and 50%. Assays of thiobarbituric acid reactive substances (TBARS) showed significantly augmented lipid peroxidation only in the abdomen (30%) where levels of antioxidant enzymes and especially luciferase are low. In contrast, exposure to hypoxia (2% O2) led to significant increases in prothorax citrate synthase (85%), succinate dehydrogenase (25%), and lactate dehydrogenase (30%) activities, but not in luciferase or antioxidant enzyme levels. LME administration alone decreased luciferase activities 20% but did not alter prothorax SOD activity. Prothorax SOD activity was increased by concomitant LME and hyperoxia treatments (30%), along with higher levels of TBARS (25%) and protein reactive carbonyl groups (50%). Altogether these data suggest that in elaterids, bioluminescence and reactions catalyzed by antioxidant enzymes may cooperate to minimize oxidative stress.
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PMID:Bioluminescence as a possible auxiliary oxygen detoxifying mechanism in elaterid larvae. 958 7

The comet assay (single cell gel electrophoresis) is a novel method to assess DNA strand breaks in single cells. We studied the oxidant sensitivity of cultured primary and transformed (MeT-5A) human pleural mesothelial cells, as well as primary and transformed (BEAS 2B) human bronchial epithelial cells, and compared the results obtained with the Comet assay to other markers of oxidant effects on cells, such as depletion of intracellular high-energy nucleotides (ATP, ADP, AMP), accumulation of products of nucleotide catabolism (xanthine, hypoxanthine, uric acid), and release of lactate dehydrogenase (LDH). The cells were exposed for 5 min to 4 h to 50-500 microM H2O2 or to 5-50 microM menadione. Significant tail moment increase, which is a marker of DNA strand breaks in the Comet assay, and intracellular nucleotide depletion occurred simultaneously in MeT-5A and BEAS 2B cells during the first 30-60 min of exposure to H2O2 and menadione. In the Comet assay variation between the individual cells could be detected. LDH release, a marker of cell injury, showed that mesothelial cells were far more sensitive than epithelial cells to oxidant-induced lytic cell injury. MeT-5A and BEAS 2B cells contained similar intracellular antioxidant enzyme activities, which may explain their similar oxidant sensitivity in the Comet assay. A significant increase (164%) in the tail moment was detectable in MeT-5A cells exposed to 50 microM H2O2 for 30 min. This returned to control level during the 4 h of continuing exposure. A 30 min exposure of 25 microM menadione caused a 61% increase in the mean tail moment but, unlike with H2O2, the change was irreversible during the following 4 h incubation. We conclude that human pleural mesothelial cells and bronchial epithelial cells show similar oxidant sensitivity when assessed by the Comet assay, but various oxidants differ in their potency in causing DNA breaks in these cells.
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PMID:DNA single strand breaks and adenine nucleotide depletion as indices of oxidant effects on human lung cells. 962 62

Short term hypoxia induced endothelial cells (ECs) injury, as manifested in increasing lactate dehydrogenase (LDH) release and malondialdehyde (MDA) content, decreasing nitric oxide (NO) production and antioxidant enzyme glutathione peroxidase (GSH-Px) activity and increased intracellular calcium concentration, which were further exaggerated by reoxygenation. Administration of 200 U/ml superoxide dismutase (SOD) before hypoxia could partially prevent EC from such injuries, suggesting that the presence of oxygen free radicals may be one of the main factors involved in hypoxia-reoxygenation injury. The ameliorative effect of SOD in case is obviously due to elimination of oxygen free radicals.
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PMID:[Protection of superoxide dismutase on hypoxia-reoxygenation injury to endothelial cell]. 986 86

During both mild and severe ischemia, vascular endothelial cells lining large and small vessels of the ischemic organ are exposed to oxygen-derived free radicals resulting in oxidative damage to the organ. Heat shock has been shown to induce thermotolerance and also protect against ischemic injury, possibly via increased synthesis of heat shock proteins (HSPs). We hypothesized that heat shock preconditioning may protect human endothelial cells against oxidative damage. Cultured human umbilical vein endothelial cells (HUVEC) were subjected to heat shock (42 degrees C, 1 h) and allowed to recover for 2 or 20 h, at which times the cells were oxidatively stressed for 1 h by exposing them to 100-200 mumol/l of hydrogen peroxide (H2O2). Cellular damage was assessed immediately and 18 h later by morphology and release of lactate dehydrogenase (LDH). No protection of HUVEC was seen using the 2-hour recovery interval, but a significant protection (P < 0.05) was observed after the 20-hour delay. Northern blot analysis at 1 and 2 h after heating showed induction of HSP-70 mRNA. Western blot analysis demonstrated a significant increase in HSP-72 protein after 2 as well as 20 h of recovery from heat shock, although the amounts of protein at the two times were not significantly different. Furthermore, no differences in the activity of the antioxidant enzyme catalase were observed between heated and unheated HUVEC at 2 and 20 h after heat preconditioning. Thus, heat shock preconditioning induces delayed protection against oxidative injury in HUVEC, and the mechanism of protection appears to involve more than the expression of HSP-72 or activity of catalase.
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PMID:Heat shock provides delayed protection against oxidative injury in cultured human umbilical vein endothelial cells. 999 May 44

The present study was designed to investigate whether cocaine modifies the production of reactive oxygen species, affects cellular enzyme-mediated antioxidant defense systems and, subsequently, promotes apoptosis and/or necrosis of hepatocytes. Primary cultures of hepatocytes isolated from phenobarbital-induced rats were exposed to cocaine (0-1000 microM) for 24 hr, and cell death (apoptosis or necrosis), antioxidant enzyme activities and mRNA levels, and peroxide generation were determined. Cocaine cytotoxicity by apoptosis was observed by detecting apoptotic nuclei using optic microscopy and by measurement of the hypodiploid peak (<2C) in DNA histograms obtained by flow cytometry. Necrosis was evidenced by lactate dehydrogenase (LDH) leakage, and peroxide production was quantified with 2',7'-dichlorodihydrofluorescein diacetate. Low concentrations of cocaine (less than 100 microM) resulted in an increase in dichlorofluorescein fluorescence, associated with an enhancement in apoptotic cell death and sharp decreases in the enzyme activities and RNAs of catalase and manganese-superoxide dismutase (Mn-SOD). The progressive decrease in peroxide production in cell cultures detected in the range of 250-1000 microM cocaine was associated with increases in LDH leakage and decreases in the percentage of apoptotic cells, accompanied by low levels in catalase and Mn-SOD enzyme activities and mRNAs, without apparent changes in apoptosis. These data indicate that oxygen radicals may contribute directly or indirectly to cocaine-induced apoptosis in cultured hepatocytes. We conclude that, in primary hepatocyte cultures, cocaine-induced cell death by necrosis was dependent on cocaine concentration, while cell death by apoptosis was parallel to peroxide concentration. The down-regulation of the gene expression of antioxidant enzyme systems should be one of the mechanisms involved in cocaine toxicity.
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PMID:Cocaine cytotoxicity in hepatocyte cultures from phenobarbital-induced rats: involvement of reactive oxygen species and expression of antioxidant defense systems. 1044 89

Short-term effects of physiological concentrations of conjugated linoleic acid (CLA) on membrane integrity, metabolic function, cellular lipid composition, lipid peroxidation, and antioxidant enzymes were examined using rat hepatocyte suspension cultures. Incubation with CLA (5-20 ppm) for 3 h decreased the ability of hepatocyte plasma membranes to exclude trypan blue by approximately 25%, and caused leakage of cytosolic lactate dehydrogenase (LDH) into the medium. The significant decrease (P< 0.02) in hepatocyte viability as measured by LDH leakage during cell incubation with 10 and 20 ppm CLA was not associated with significant changes in cellular ATP content. Protein synthesis in hepatocytes was elevated (P < 0.05) in the presence of 5 and 10 ppm CLA, but at a higher concentration (20 ppm), protein synthesis was similar to that of control cells. Gluconeogenesis was maintained in cells incubated with lower concentrations of CLA (5 and 10 ppm) but was decreased (P < 0.02) at the higher concentration. Incubation with 20 ppm CLA for 3 h did not affect the specific activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase, the rate-limiting enzyme of cholesterol synthesis. Both cis-9,trans-11/trans-9,cis-11, and cis-10,trans-12/trans-10,cis-12 isomers of CLA were incorporated to a similar level into hepatocytes. Levels ranged from 3.9 to 4.1%, respectively, of total fatty acids in neutral lipids, and from 0.7 to 0.8%, respectively, of total fatty acids in phospholipids. Cellular lipid peroxidation remained unchanged in the presence of CLA (5-20 ppm), despite significant inhibition (P < 0.05) of superoxide dismutase. Catalase activity was maintained near control levels in the presence of 5 and 10 ppm CLA but was significantly decreased in the presence of 20 ppm CLA. Glutathione peroxidase activity was significantly decreased in the presence of 10 ppm CLA. The apparent sensitivity of the antioxidant enzyme defense system of liver cells to CLA, coupled with the lack of effect of CLA on lipid peroxidation in cells, suggests that cytotoxic effects of CLA as described by LDH leakage and decreased gluconeogenesis were not mediated by a prooxidant action in hepatocytes.
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PMID:The effect of conjugated linoleic acid on the antioxidant enzyme defense system in rat hepatocytes. 1052 94


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