Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.6.1.1 (aspartate aminotransferase)
21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Glutatione peroxidase activity (EC 1.11.1.9) and erythrocyte stability were measured in Friesian bull calves which were given for 36 weeks semi-purified diets either adequate or low in selenium or vitamin E or both. 2. Dietary Se or vitamin E content had no effect on growth rate and haematlogical values. None of the calves exhibited clinical deficiency symptoms and serum aspartate amino transferase (EC 2.6.1.1) and creatine phosphokinase (EC 2.7.3.2) activities remained normal. Heart and skeletal muscles of all calves appeared macroscopically and microscopically normal ato autopsy. 3. Glutathione peroxidase activity in plasma, blood and other tissues, except the testis, was significantly lower in calves receiving low dietary Se but was independent of dietary vitamin E content. 4. Plasma vitamin E levels decreased rapidly and to very low levels in calves given low vitamin E diets irrespective of the Se content of the diet. 5. A low dietary vitamin E intake increased the susceptibility of erythrocytes to auto- and peroxidative haemolysis whereas a low Se intake in the presence of adequate vitamin E did not. However, erythrocytes from calves receiving low Se and low vitamin E were more susceptible to peroxidative haemolysis than erythrocytes from calves receiving low vitamin E and adequate Se. The effect of dietary vitamin E content on osmotic haemolysis induced by hypotonic saline was variable. 6. The results suggest that measurement of blood glutathione peroxidase activity and the susceptibility of erythrocytes to auto- or peroxidative haemolysis could be used for the differential diagnosis of subclinical Se and vitamin E deficiency in ruminants.
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PMID:Glutathione peroxidase activity and erythrocyte stability in calves differing in selenium and vitamin E status. 728

Acute and chronic effects of Se as sodium selenite given as a supplement in the drinking water of Sprague-Dawley rats for 35 d, 1 yr, and 2 yr are compared. For the 35-d study the experimental groups were untreated controls and rats supplemented with 1, 4, 8, 16, and 64 ppm Se. Survival was 100% in the control and 1 and 4 ppm groups, decreased in the 8 and 16 ppm groups, and was zero in the 64 ppm group. Body weights increased and were equivalent in the control and 1 and 4 ppm groups and substantially decreased in the 16 and 64 ppm groups., Serum alkaline phosphatase and glutamic-oxaloacetic transaminase (SGOT) increased with 16 ppm Se and higher supplements. Se toxicity was apparent in microscopic pathology showing liver congestion, fatty degeneration of parenchymal cells, and necrosis. In the chronic studies untreated controls are compared with rate receiving 4 ppm Se in the drinking water. In general, the weight gains throughout were equivalent for both groups. The 1-yr survival in each was above 90% and the 2-yr survival above 50%. With increased age there was a slight reduction in hemoglobin and white blood cells. The latter effect was greater in Se-treated then in control rats. Several serum components were equivalent in both groups, including alkaline and acid phosphatase, SGOT, protein, glucose, and sialic acid. Liver glutathione peroxidase was half and Se levels in the Se-treated rats were twice those in the controls. Data are presented for male rats in the chronic study with occasional reference to data on females. The parameters measured in the chronic study are highly dependent on the age of the rat when Se-supplemented drinking water is initiated.
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PMID:Toxicological effects of sodium selenite in Sprague-Dawley rats. 733 30

Se as sodium selenite was administered by gavage (three consecutive times) and as drinking water supplements for 46 d to male and female Swiss mice. With respect to survival in 7-wk-old mice, Se was less toxic in males than in females when gavaged. Drinking water supplements of 1-64 ppm Se resulted in 1 male and 1 female death in mice first given Se at 7 wk of age. Se supplements to the drinking water of adult (18-wk-old) mice was less toxic in females. All young (7-wk-old) and adult (18-wk-old) mice provided 1-16 ppm Se in the drinking water survived the 46-d treatment, but in adult mice 64 ppm Se significantly reduced survival. Only 64 ppm Se supplements caused a sharp reduction in body weight in young and adult mice of both sexes. Supplements of 1-8 ppm Se in all mice elicited growth responses similar to those of untreated controls. Occasional liver and kidney congestion, liver necrosis, parenchymal cell degeneration, and bile duct proliferation were observed in control and treatment groups. Serum alkaline phosphatase and glutamic-oxaloacetic transaminase (SGOT) increased with 32 ppm Se and higher supplements. Survival, growth, serum enzymes, and pathology were normal in untreated controls and in mice of growth ages and sexes give 1, 4, and 8 ppm Se supplements. A chronic toxicity study was conducted in female Swiss mice given 1, 4, and 8 ppm Se supplements for 50 wk. The survival of Se-treated groups was more than 90% and that of controls was only 72% after 50 wk. All mice gained weight, but the group treated with 8 ppm Se gained half as much as other groups. Both liver Se and glutathione peroxidase activity increased in Se-treated mice compared to controls at 25 and 50 wk. A reduced white blood cell count and increased alkaline phosphatase and SGOT suggested a mild toxic effect of the 8 ppm Se supplement in the chronic study.
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PMID:Toxicological effects of sodium selenite in Swiss mice. 733 31

It has recently been proposed that a depletion of glutathione (GSH) may be a contributing factor to viral persistence and resistance to interferon-alpha (IFN-alpha) therapy in chronic hepatitis C virus (HC) infection. The aim of this study was: (1) to compare plasma GSH levels in patients with chronic HCV infection and normal healthy controls; and (2) to correlate GSH levels with liver histology and serum HCV RNA levels. Twenty-four patients with compensated chronic hepatitis C and 27 healthy subjects were studied. Serum and heparinized plasma were prospectively prepared and frozen within 1 h of collection. Plasma glutathione and glutathione peroxidase (GP) levels were measured spectrophotometrically. The serum HCV RNA level was quantitated by the branched chain DNA signal-amplification assay. Plasma GSH levels were not decreased in patients with chronic HCV infection but were actually greater than in controls (control 1.27 +/- 0.12 micrograms ml-1, HCV 1.62 +/- 0.11 micrograms ml-1, P < 0.05). There was also no difference in plasma GP activity between these two groups (control 0.233 +/- 0.007 U ml-1, HCV 0.230 +/- 0.007 U ml-1). Among the patients with chronic HCV infection, there was no correlation between either plasma GSH or GP levels and the serum alanine aminotransferase (ALT) or aspartate aminotransferase (AST), serum HCV RNA level, or liver histology. This study demonstrates that chronic HCV infection does not decrease the plasma GSH and GP levels.
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PMID:Plasma glutathione concentration in patients with chronic hepatitis C virus infection. 748 49

The kidney is probably the major site of production of the plasma enzyme glutathione peroxidase (GSHPx-P). For this study, GSHPx-P activity was determined in 40 healthy people, in 34 patients with differing degrees of renal impairment, and in hemodialysis patients from whom blood samples were withdrawn either before or after each session (18 patients) or throughout the dialysis session (27 patients). Hemodialysis patients were treated by means of different techniques (bicarbonate hemodialysis, hemodiafiltration, and acetate free biofiltration), and different membranes (cuprophane, polyacrylonitrite, and polymethylmethacrylate). The following results were obtained: 1) GSHPx-P activity was significantly decreased in renal impairment patients; 2) GSHPx-P activity negatively correlated with serum creatinine values in renal impairment patients (r = -0.55; p < 0.001); and 3) the enzyme activity slightly increased after the session in hemodialysis patients. The following conclusions can be drawn: GSHPx-P activity could be new index of renal function, because it was decreased in patients with renal failure; the decrease in GSHPx-P activity paralleled the severity of renal impairment, and was maximal in hemodialysis patients; GSHPx-P activity was slightly raised at the end of the hemodialysis session, concomitant with other enzyme activities (aspartate transaminase, alanine transaminase, and alkaline phosphatase) and total protein concentration. This seems to be attributable to the process of water loss rather than other hypothetical mechanisms, such as A) enzyme activation by either peroxide generation during blood-membrane contact, or by the removal of a hypothetical inhibitor; and B) de novo synthesis in the residual renal mass or in other sites of production.
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PMID:The plasma glutathione peroxidase enzyme in hemodialyzed subjects. 785 33

The subacute oral toxicity of selenocystine and chemical form of selenium in the liver following exposure to this compound were assessed in ICR male mice. Animals were dosed 6 days/week for 30, 60 or 90 days with 0, 5, 10 or 15 mg/kg per day. Body weight gain decreased with dosage. The activities of aspartate aminotransferase and alanine aminotransferase in plasma were significantly elevated at the highest dose level after 60 days and at the two higher dose levels after 90 days of exposure. However, the level of selenium content in the liver was the same at the two higher dosages at both 60 and 90 days of exposure. The subcellular distribution of selenium in the liver from mice treated with selenocystine showed that the major part of the total selenium content, 68.3-72.1%, existed in the cytosolic fraction. Sephadex G-150 chromatograms of liver cytosol of the animals administered selenocystine revealed three selenium-containing fractions which involve glutathione peroxidase (molecular weight 80,000) high molecular (molecular weight 55,000-60,000) and low molecular (molecular weight < 10,000) substances. Selenium content and acid-volatile selenium content in the high molecular weight fraction increased with exposure time to selenocystine. Thus, in a subacute toxicity study selenocystine given for 90 days caused hepatic damage in mice, depending on the acid-volatile selenium content in the liver cytosol.
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PMID:Toxicity and chemical form of selenium in the liver of mice orally administered selenocystine for 90 days. 817 87

Experimentally induced salinomycin toxicosis in weanling pigs showed typical clinical signs of an intoxication with a polyether antibiotic. Severe ataxia and recumbency were the most prominent symptoms, which could be attributed to acute skeletal muscle necrosis by estimation of muscle enzyme activities (creatine kinase, aspartate aminotransferase) and histopathological examination. Intoxication had neither influence on concentrations of vitamin E and selenium-dependent glutathione peroxidase in plasma and different organs nor on contents of fatty acids in skeletal muscles. No signs of increased lipid peroxidation in muscle tissue could be found. Prophylactic application of vitamin E or selenium one day before administration of salinomycin as well as treatment on the following days produced no protective effects. The treated pigs showed equal clinical and pathomorphological alterations as the untreated animals, although applications caused a significant increase of alpha-tocopherol and glutathione peroxidase concentrations in blood and different organs.
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PMID:[The effect of treatment with vitamin E or selenium on the course of salinomycin poisoning in swine]. 820 64

The in vivo effects of human placental extract (1-4 ml/kg) on hepatic lipid peroxidation, blood and liver glutathione (GSH) levels and several enzymes associated with the antioxidant defence mechanism; i.e., catalase, glutathione peroxidase, glutathione reductase and glutathione S-transferase, together with some blood biochemical responses were investigated in rats. At an optimal dose level (4 ml/kg), a single acute intraperitoneal administration of the extract caused a significant enhancement (49.9%; p < 0.001) of lipid peroxidation with a decline in GSH level both in blood (45.1%; p < 0.001) and liver (61.0%; p < 0.001) in comparison to control animals. Activities of catalase, glutathione peroxidase and glutathione reductase were inhibited in a dose-responsive way by the treatment with the extract which also increased the activity of glutathione S-transferase in a dose-dependent manner. The extract was found to be hepatotoxic in terms of elevation of serum glutamate oxaloacetate transaminase, serum glutamate pyruvate transaminase, serum lactate dehydrogenase and blood methemoglobin concentration. Results of this study suggest the adverse consequences of the administration of the extract due to its substantial ability to alter normal cellular processes.
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PMID:Elevated lipid peroxidation, decreased glutathione levels and changes in glutathione-related enzymes in rats treated with human placental extract. 821 15

Chloroform (CHCl3) is widely used in the manufacture of drugs, cosmetics, plastics and cleaning agents. It is also found in chlorinated drinking water. This study was designed to investigate the toxic effect of CHCl3 on isolated male rat hepatocytes using several toxicity parameters. The hepatocytes were isolated by a collagenase perfusion technique and the cell viability was determined by Trypan blue exclusion. The leakage of cytosolic enzymes such as aspartate transaminase (AST) and alanine transaminase (ALT) after treatment with CHCl3 was measured. Reduced glutathione content (GSH) and its related enzymes, glutathione reductase (GSH-Rx) and glutathione peroxidase (GSH-Px), were also evaluated to study the effect of CHCl3 on hepatocytes. Exposure to 100 and 1000 ppm CHCl3 results in a significant decrease in cell after 30 min incubation. However, the effect of 1 and 10 ppm concentrations was observed at 60 min incubation. AST leakage was significantly increased in all treatment groups, while ALT was significantly increased at 100 and 1000 ppm CHCl3 after 60 and 30 min, respectively. As early as 15 min, GSH was decreased significantly at 1000 ppm, but at 100 and 10 ppm CHCl3 the decrease in GSH began after 30 and 120 min, respectively. GSH-Px activity did not changed. However, the activity of GSH-Rx was significantly decreased at 1000 ppm CHCl3 and at the same time GSH content was decreased. The data indicate that the toxic effect of CHCl3 was dose- and time-dependent. The degree of GSH depletion correlated with increased cytotoxicity and decreased GSH-Rx activity due to CHCl3.
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PMID:The mechanism of chloroform toxicity in isolated rat hepatocytes. 835 69

Mercury is the major component of dental amalgam restorative material, which typically has 50% pure elemental mercury. It is also used in some skin creams, and in the manufacturing of plastic, drugs and fungicides. The present study was designed to investigate the toxicity of methyl mercury (MeHg+) on isolated rat hepatocytes using several toxicity parameters. The hepatocytes were isolated by a collagenase perfusion technique and were incubated with different concentrations of MeHg+ (0.1-100 ppm) for 2 h. Through the incubation period the viability was determined by Trypan blue exclusion. Reduced glutathione (GSH) content and its enzymes, glutathione peroxidase (GSH-PX) and glutathione reductase (GSH-RX) were measured. Leakage of enzymes such as aspartate transaminase (AST), and alanine transaminase (ALT) were determined. The cell viability was reduced significantly after 1 h incubation when 0.1 and 1 ppm MeHg+ were applied. The decrease in the cell viability was dose- and time-dependent. A depletion of GSH content was observed with 100 ppm MeHg+ after 30 min of incubation. A significant decrease in GSH-RX was observed with 100 ppm during 15 and 30 min of incubation, while 10 ppm of MeHg+ significantly increased ALT leakage after 60 min. However, there was a significant increase in AST leakage with 100 ppm only. The present investigation indicates that the toxic effect of MeHg+ is most likely cytosolic enzyme related.
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PMID:The mechanism of methyl mercury toxicity in isolated rat hepatocytes. 835 70


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