UMLS:C0432222 - FACTA Search

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Query: UMLS:C0432222 (SEM)
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This is the first experiment to investigate the effect of heat and cold stress on glutathione metabolism in human erythrocytes. We immersed men at three different water temperatures for 10 min. At 39 degrees C, no remarkable changes were observed. Levels of glutathione (GSH) decreased from 2.44 (0.14) to 1.80 (0.10) mumol.ml red blood cells-1 [mumol.ml RBC-1; mean (SEM); P < 0.0005] and those of lipid peroxides increased from 1.87 (0.03) to 2.06 (0.04) nmol.ml RBC-1 (P < 0.01) after the immersion at 42 degrees C. In contrast, levels of GSH increased from 2.46 (0.17) to 2.91 (0.17) mumol.ml RBC-1 (P < 0.05) and those of lipid peroxides did not change after the immersion at 25 degrees C. The activities of glutathione peroxidase decreased from 35.90 (1.83) to 34.33 (1.66) IU.g Hb-1 (P < 0.01) after the immersion at 42 degrees C; however, these activities did not change after the immersion at 25 degrees C. The activities of glutathione reductase (both active and inactive forms) showed no changes at any temperatures. These changes indicate that heat stress causes oxidative stress in the human body; however, cold stress is thought to augment the activity of the antioxidative defence system. It is suggested that body exposure to hot environmental conditions should not be recommended for patients suffering from a damaged antioxidative defence system.
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PMID:Effect of thermal stress on glutathione metabolism in human erythrocytes. 816 28

The effects of hypoxia (95% N2/5% CO2) followed by hyperoxia (95% O2/5% CO2) were determined in isolated lungs of premature (gestational age 128 to 135 d) and full-term (postnatal age 0 to 5 d) lambs perfused with autologous blood (100 mL.min-1.kg body weight-1). In full-term lungs, hypoxia-hyperoxia compared with hypoxia alone decreased pulmonary artery pressure and increased weight gain and extravascular lung water. In premature lungs, the increase in weight gain was greater and was associated with hemorrhage and increased pulmonary arterial and peak airway pressures. Papaverine eliminated reoxygenation-induced differences in pulmonary artery pressure, peak airway pressure, and weight gain in both age groups. Osmotic reflection coefficients for total protein and albumin, measured by a modification of the filtered volume technique, averaged 0.591 +/- 0.054 (SEM) and 0.465 +/- 0.054 (SEM), respectively, and were not altered by reoxygenation or age. Catalase activity in lung tissue and erythrocytes was lower in premature lambs, but there were no age-related differences in superoxide dismutase or glutathione peroxidase activities. These results demonstrate that hypoxia-hyperoxia in isolated lamb lungs increased lung weight due to edema formation in full-term lamb lungs and hemorrhage in premature lamb lungs and that this increase was greater in premature lamb lungs. We speculate that the weight gain caused by reoxygenation was due to a vasodilation-induced increase in surface area in full-term lamb lungs and a vasoconstriction-induced increase in vascular pressure in premature lamb lungs.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Developmental differences in catalase activity and hypoxic-hyperoxic effects on fluid balance in isolated lamb lungs. 851 Oct 27

An increase in antioxidant enzyme activity after acute exercise and exercise training have been reported by many investigators including our laboratory. This study was undertaken in order to determine whether an increase in activity of superoxide dismutase (MnSOD and CuZnSOD), catalase (CAT) and glutathione peroxidase (GSH-Px) during exercise training was associated with the increased levels of respective mRNAs. Male Fisher-344 rats (age 77 weeks) were given exercise training for 9 weeks on the treadmill. Enzyme activity and mRNA's were measured in the heart tissue 23 hr after stopping exercise training. The heart tissues of exercised and sedentary control rats were used to isolate mRNAs encoding MnSOD, CuZnSOD, CAT and GSH-Px by northern blotting experiments. The intensities of mRNA bands were measured by densitometric scanning of the autoradiograms. Northern blot for tubulin was used to normalize the respective intensities. Compared to sedentary controls, the level of mRNAs of enzymes MnSOD, CAT and GSH-Px were found to increase by 126 +/- 5, 133 +/- 6, and 138 +/- 5 percent of sedentary control (mean +/- SEM) respectively, due to exercise training. Corresponding values for these enzyme activity were 153 +/- 19%, 255 +/- 7%, 133 +/- 2% of sedentary control. These results suggest that post-translational modification of these enzyme activity increased in response to exercise training more than increased transcription in aged rats.
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PMID:Comparative effects of exercise training on transcription of antioxidant enzyme and the activity in old rat heart. 895 Jan 34

Decreased plasma selenium (Se) levels are common in critically ill patients. Oxidative stress is regarded as one possible cause of the Se deficiency. We investigated in 20 critically ill patients with decreased plasma selenium concentrations the antioxidant metabolism during parenteral selenium supplementation (week 1: 2 x 500 micrograms; week 2:1 x 500 micrograms, week 3:3 x 100 micrograms sodium selenite). As marker of oxidative stress we measured the plasma malondialdehyde levels on days 0, 1, 3, 7, 14, and 21. The content of reduced and oxidized glutathione as well as the leucocyte activity marker elastase were estimated on the same days. Initial plasma Se levels were considerably decreased (0.44 +/- 0.1 mumol/l, mean +/- SEM). After one day of supplementation Se concentrations were in the reference range. Plasma malondialdehyde levels and the ratio of oxidized and reduced glutathione were initially elevated and decreased beginning on day 3 of supplementation. The mean elastase level was 113 +/- 10 micrograms/l on day 0. On day 3 elastase values decreased significantly (85 +/- 13 micrograms/l, p < 0.05; day 21, 19 +/- 7 micrograms/l, p < 0.001). Antioxidant metabolism showed significant changes beginning after 72 hours of therapy. This latency may be explained with the induction of the enzyme glutathione peroxidase. The lowered plasma Se concentrations measured in the critically ill patients and the significant effects on antioxidant metabolism during supplementation emphasized the importance of selenium administration in these patients.
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PMID:Parenteral selenium supplementation in critically ill patients--effects on antioxidant metabolism. 955 39

The possible cardioprotective effects of preconditioning by ischaemia (IPC) or a low dose of H2O2 (HPC) prior to a high dose of H2O2 was investigated. Langendorff-perfused rat hearts (n = 10 in each group) were subjected to 10 min of 140 micromol/L H2O2 and 30 min recovery after either (1) control perfusion, (2) 20 micromol/L H2O2 for 10 min, recovery 10 min, or (3) 2 x 2 min global ischaemia and 5 min reperfusion. 140 micromol/L H2O2 increased left ventricular end-diastolic pressure from 0 to 68+/-8 mmHg in controls (mean+/-SEM), which was attenuated by IPC (46+/-9 mmHg, p<0.001) and HPC (18+/-4 mmHg, p < 0.001 compared to controls, p < 0.01 compared to IPC). HPC, but not IPC, improved coronary flow (p < 0.02) and left ventricular developed pressure (p < 0.001) during recovery. Troponin T release was similar in all groups. Tissue thiobarbituric acid reactive substances, antioxidant capacity, catalase, and glutathione peroxidase were not influenced by 140 micromol/L H2O2. H2O2 decreased the level of tissue glutathione. This reduction was augmented by HPC (p <0.02) and attenuated by IPC (p < 0.02). H2O2 increased superoxide dismutase (p < 0.04). The increase was attenuated by IPC (p < 0.05), but not influenced by HPC. HPC efficiently protected cardiac function in H2O2-induced cardiac injury, while IPC had only a small protective effect. The functional protection cannot be explained by reduction of irreversible injury, attenuation of lipid peroxidation, or modification of tissue antioxidant parameters.
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PMID:Preconditioning with hydrogen peroxide (H2O2) or ischemia in H2O2-induced cardiac dysfunction. 980 55

Oxidative stress imposed by reactive oxygen species is now believed to contribute to hypertension, atherosclerosis and ageing of the vasculature all involving a loss of relaxation. The antioxidant enzymes glutathione peroxidase, superoxide dismutase and catalase play a crucial role in defending against the ravages of oxidative stress. Our purpose was to characterize age-related changes in glutathione peroxidase, superoxide dismutase and catalase in the rat aorta. Aortas were extracted from seven young (4 months), seven middle aged (18 months) and seven old (24 months) animals. Analysis of variance was used with Fisher-LSD post hoc to determine mean differences among glutathione peroxidase, superoxide dismutase and catalase. Aortic glutathione peroxidase activities rose steadily with age expressed in micromol mg protein-1 min-1 +/- SEM (young: 141 +/- 22; middle aged: 198 +/- 18; old: 229 +/- 26) reaching significance between young and old. Superoxide dismutase activities significantly decreased in middle aged when compared with young (young: 22 +/- 2 vs. middle aged: 15 +/- 2 U mg protein-1) before trending upward again in old age (19 +/- 2). Catalase activities dropped significantly between young and old when expressed in mU mg protein-1 (young: 230 +/- 30; middle aged: 173 +/- 18; old: 144 +/- 23). Ratios for the various enzymes indicate a shrinking contribution of catalase with ageing, with an enhanced role for glutathione peroxidase in the antioxidant defence. These data in aortas of ageing rats show a complex alteration of the antioxidant profile.
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PMID:Ageing alters aortic antioxidant enzyme activities in Fischer-344 rats. 1046 56

An in vivo sulfur mustard (HD) vapor exposure model followed by bronchoalveolar lavage was developed previously in this laboratory to study biochemical indicators of HD-induced lung injury. This model was used to test two treatment compounds--niacinamide (NIA) and N-acetyl cysteine (NAC)--for their ability to ameliorate HD-induced biochemical changes. Anesthetized rats were intratracheally intubated and exposed to 0.35 mg of HD in 0.1 ml of ethanol or ethanol alone for 50 min. At the beginning of the exposure (t = 0), the rats were treated with either NIA (750 mg kg(-1)) or NAC (816 mg kg(-1)), i.p. At 24 h post-exposure, rats were euthanized and the lungs were lavaged with saline (three 5-ml washes). One milliliter of the recovered lavage fluid was analyzed for cellular components. The remaining fluid was centrifuged (10 min at 300 g) and the supernatant was assayed on a Cobas FARA clinical analyzer for lactate dehydrogenase (LDH), gamma-glutamyltransferase (GGT), albumin (ALB), total protein (TP) and glutathione peroxidase (GP). The HD alone and HD+NIA treatment caused significant increases in all of the biochemical parameters compared with control levels. The NAC treatment yielded LDH, ALB and TP values that, although elevated, were not significantly different from the control. The GP levels were significantly higher than the control but significantly lower than the HD alone levels, indicating some protection compared with the HD alone group. The GGT levels were unaffected by NAC compared with HD alone. Cytological analysis of lavage fluid showed that the percentages of neutrophils were 5.3 +/- 1.0 (mean +/- SEM) for control, 46.6 +/- 4.5 for HD, 31.4 +/- 4.7 for HD + NIA and 21.6 +/- 4.7 for HD + NAC, respectively. The neutrophil counts were significantly higher for the three HD-exposed groups vs controls; however, the NAC-treated group had neutrophil counts lower than HD alone, indicating decreased inflammatory response. These results show that NAC may be useful as a potential treatment compound for HD-induced lung injury.
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PMID:Treatment of sulfur mustard (HD)-induced lung injury. 1142 23

We previously showed that cryopreservation of bull spermatozoa in egg yolk Tris extender (EYTG) significantly reduced the intracellular level of thiols. Other studies showed the beneficial effects of adding antioxidants to cryopreserved bull spermatozoa. These studies led us to investigate the effects of various thiols, an important class of antioxidants, on sperm motility of cryopreserved bull semen in a commonly used extender, EYTG. Sperm motility was analyzed by computer-assisted semen analysis (CASA). After thawing, a diluted pool of bull semen was incubated at 38.5 degrees C in airtight tubes with the following thiols for 6 hours: glutathione (GSH/GSSG), cysteine, N-acetyl-L-cysteine (NAC) and 2-mercaptoethanol in the presence or absence of oxidative stress. The oxidative stress was caused by adding H2O2 (100 microM) to diluted semen. Incubation of diluted bull semen in EYTG at 38.5 degrees C over a period of 6 h decreased sperm motility by approximately 9 fold from the start (72 +/- 3, mean +/- SEM, n=4) to the end (9 +/- 4, n=4) of the incubation. We found that all thiols to a concentration above 0.5 mM maintained high sperm motility for 6 h in the absence of an external source of oxidative stress (52 +/- 4, for 4 thiols). However, one mM of each thiol was required to efficiently protect sperm motility in the presence of 100 microM of H2O2 for 6 h. We also found that the GSH concentration in diluted semen was too low (microM) to adequately supply exogenous addition of 72 U/mL of glutathione peroxidase (GPx), an enzyme that detoxifies H2O2 and hydroperoxides using GSH as a cofactor. In fact, a better protection of sperm motility could be achieved with only 5 U/mL of GPx and 0.1 mM of GSH added to diluted semen. Our results also demonstrated that added GSSG (0.5 mM) in diluted semen was not regenerated efficiently to GSH over 6 h. The latter result indicated in the extender that the glutathione redox-cycle was deficient. Therefore, deleterious effects sperm motility after cryopreservation in EYTG can be counteracted by adding various thiols at mM concentration.
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PMID:Thiols prevent H2O2-mediated loss of sperm motility in cryopreserved bull semen. 1148 Jun 19

Long-duration or damaging exercise initiates reactions that resemble the acute phase response to infection and induces neutrophil priming for oxidative activity. Our objective was to establish the status of the antioxidant defences and of the oxidative equilibrium in the neutrophils of sportsmen prior to and after intense physical exercise. Nine voluntary male professional cyclists participated in this study. The exercise was a cycling mountain stage (171 km) and the cyclists took a mean +/- SEM of 270 +/- 12 min to complete it. We determined the activities of catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx), the levels and activity of superoxide dismutase (SOD), the concentrations of ascorbate, glutathione and glutathione disulphide (GSSG) and DNA levels in neutrophils. The cycling stage decreased enzyme activities expressed per DNA units: CAT (33%), SOD (38%), GPx (65%); increased ascorbate concentration in neutrophils and decreased the GSH/GSSG ratio and the enzyme activities expressed per DNA units. Neutrophils could contribute to plasma antioxidant defences against oxidative stress induced by exercise because they probably provide antioxidant enzymes and ascorbate.
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PMID:Acute phase immune response to exercise coexists with decreased neutrophil antioxidant enzyme defences. 1251 82

Cigarette smoking leads to uptake of a multitude of reactive chemicals including many electrophiles and may also give rise to oxidative stress. Human red blood cells are important targets for electrophilic and oxidant foreign compounds. We investigated the oxidative stress in erythrocytes upon cigarette smoking, and the response of antioxidant defense system against it. With this aim, simultaneous determination of erythrocyte superoxide dismutase (SOD), selenium dependent glutathione peroxidase (Se-GPx), catalase (CAT), glutathione S-transferase (GST) activities and plasma levels of thiobarbituric acid reactive substances (TBARS), and the degree of erythrocyte membrane lipid peroxidation (EMLP) were carried out in blood samples of smokers and their controls. Plasma TBARS levels and EMLP in smokers were significantly higher than the control levels (p < 0.01 and p < 0.005, respectively). SOD activity was diminished in smokers compared to nonsmoker controls (p < 0.005). Erythrocyte Se-GPx activity was also found significantly diminished in smokers (p < 0.005), while plasma Se-GPx activity was not changed. We observed that erythrocyte CAT activity was not different in smokers compared to nonsmoker controls. We found that the erythrocyte GST activity is significantly lower in young adult smokers (3.03 +/- 0.18 U/mg protein; mean +/- SEM; n = 46) than in nonsmoking contemporaries (3.98 +/- 0.26 U/mg protein; mean +/- SEM; n = 41). Together with previously reported data, it can be concluded that the decrease in GST activity leads to extra GST synthesis during erythrocyte proliferation. The same data were also analyzed for the sex differences. The statistically significant differences remained the same between nonsmoker and smoker females. Only EMLP degree and SOD activity were significantly different between nonsmoker and smoker males; however, when compared the parameters between male and female nonsmokers, GST activity was found to be significantly higher in females than that of males.
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PMID:Erythrocyte antioxidant defense response against cigarette smoking in humans--the glutathione S-transferase vulnerability. 1617 57

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