Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P17174 (aspartate aminotransferase)
 14,872 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The 7 day-long intragastric administration of ethanol and ethyleneglycol in a dose of 1/3 DL50 was studied for its effect on the circadian variations of the aspartate aminotransferase activity (AST, EC 2.6, 1.1) in the liver, brain, myocardium and kidney of male rats. The ethanol and ethylene glycol administration reduced the mean circadian enzymic activity in the above organs. Moreover, ethanol significantly reduced the amplitude of circadian variations of the AST activity in the liver, brain and kidney, while ethylene glycol--in the liver, myocardium and kidney.
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PMID:[The effect of alcohols on daily variations in aspartate amino- transferase activity in rat organs]. 258 42

Aqueous solutions of dextran and of poly(ethylene glycol) when mixed give rise to two-phase systems useful in separating cells, on the basis of their surface properties, by partitioning. Depending on whether salts with unequal or equal affinity for the two phases are chosen, phases with or without an electrostatic potential difference between the phases are obtained. At appropriate polymer concentrations the former yield cell partition coefficients (i.e., the quantity of cells in the top phase as a percentage of total cells added) based on charge-associated surface properties while the latter reflect membrane lipid-related parameters. With increasing cell age, rat erythrocytes have diminishing partition coefficients in both charged and uncharged phases. Using the elevated aspartate aminotransferase levels of younger red cells as a marker, we have not found that young mature erythrocytes of human do not have the highest partition coefficient in the red cell population as they do in rat. Experiments with isotopically labeled dog red cells yield results similar to those found with human erythrocytes. Furthermore, density-separated young and old red cells from human give overlapping countercurrent distribution curves. Finally, countercurrent distribution of human red blood cells followed by pooling of cells from the left and right ends of the distribution and subjection of these cells to a redistribution gives curves that overlap with each other and with the original countercurrent distribution. This indicates that not only are human red cells not subfractionated based on possible age-related surface alterations, but also that they are not subfractionated by partitioning based on any surface parameter. These results are consistent with our previous findings that membrane sialic acid/hemoglobin absorbance is essentially constant through the extraction train after countercurrent distribution of human erythrocytes in a charged phase system; and with the recent reports of others that there is no difference in electrophoretic mobility between human young and old red cells.
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PMID:Aging of erythrocytes results in altered red cell surface properties in the rat, but not in the human. Studies by partitioning in two-polymer aqueous phase systems. 616 60

Polyethylene glycol-6000 (PEG) was evaluated as a clearing agent for lipemic serum from dogs. Effects of PEG-treatment in lipemic and non-lipemic samples were determined for 13 chemical and enzymatic assays (glucose, BUN, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, amylase, total protein, albumin, sodium, potassium, chloride, phosphorus, and calcium). Control samples for lipemic sera were prepared by ultracentrifugation. Treatment with PEG cleared all lipemic samples. Regression lines for all lipemic samples were highly significant (P less than 0.0001) and the SD of the control values around the regression lines were small compared with the mean value for an assay. The technique was simple, quick, and inexpensive. With proper validation, reliable predictions of true serum values could be calculated for lipemic serum samples for all assays studied.
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PMID:Polyethylene glycol-6000 as a clearing agent for lipemic serum samples from dogs and the effects on 13 serum assays. 649 14

The molar activity of crystalline mitochondrial aspartate aminotransferase is decreased to 10% of that of the enzyme in solution. The activity was measured in suspensions of non-cross-linked microcrystals (average dimensions 22 microns X 5 microns X 0.8 microns) in 30% (w/v) poly(ethylene glycol). Kinetic tests ruled out the possibility that diffusion of the substrate in the crystals is rate-limiting. The observed decrease in catalytic efficiency can be attributed exclusively to crystal-packing effects. A direct inhibition by poly(ethylene glycol) is excluded because poly(ethylene glycol), with average Mr 6000, cannot penetrate the liquid channels of the crystals, owing to its large Stokes radius. The crystals examined were triclinic and of the same habit as those used for high-resolution X-ray-crystallographic analysis [Ford, Eichele & Jansonius (1980) Proc. Natl. Acad. Sci. U.S.A. 77, 2559-2563]. The catalytic competence of crystalline aspartate aminotransferase confirms the relevance of the spatial model of this protein for the elucidation of its mechanism of action.
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PMID:Catalytic activity of non-cross-linked microcrystals of aspartate aminotransferase in poly(ethylene glycol). 687 Aug 40

Macroenzymes are enzymes in plasma that have a higher molecular mass than the corresponding enzyme normally present under (patho) physiological conditions. Macro species have been described for most routinely measured enzymes, but with only a few reports of macro species with aspartate aminotransferase (AST), and in particular very few reports in children and adolescents. Routine biochemical analysis in a 15-year-old girl presenting with lower back pain revealed an isolated raised AST as part of a liver function test profile. Polyethylene glycol precipitation and gel filtration chromatography showed this to be a macro species.
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PMID:A paediatric case of macro aspartate aminotransferase. 1848 8

Previous studies identified amino acid (aa) substitutions of the hepatitis C virus core region of genotype 1b (HCV-1b core region) and elevated serum alpha-fetoprotein (AFP) levels as predictors of poor virologic response to pegylated interferon (PEG-IFN) plus ribavirin (RBV), and also as risk factors for hepatocarcinogenesis. The present study evaluated the impact of aa substitutions of HCV-1b core region on AFP, as a surrogate marker of hepatocarcinogenesis, on AFP levels in 569 Japanese patients with HCV-1b but without HCC, and investigated the predictive factors of elevated AFP (> or =11 microg/L). High AFP levels were detected in 27.4% of the patients. The rate of hepatocarcinogenesis in a group of 109 patients who received IFN monotherapy and followed-up for 15 years, was significantly higher in patients with abnormal than normal AFP. Multivariate analysis of 569 patients identified fibrosis stage (F3,4), aspartate aminotransferase (> or =76 IU/L), substitution of aa 70 (glutamine or histidine), and platelet count (<15.0 x 10(4)/microl) as significant determinants of elevated AFP. In 49 patients with abnormal AFP levels and substitutions at aa 70 who were treated with PEG-IFN + RBV, the rate of normalization of AFP was significantly lower in non-virological responders (28.6%) than in transient (71.4%) and sustained (100%) virological responders. The results indicated that substitution of aa 70 of HCV-1b core region is an important predictor of elevated AFP in non-HCC patients, and that eradication of the mutant virus normalizes AFP. The results highlight the importance of eradication of mutant type virus of aa 70 for reducing the risk of hepatocarcinogenesis.
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PMID:Substitution of amino acid 70 in the hepatitis C virus core region of genotype 1b is an important predictor of elevated alpha-fetoprotein in patients without hepatocellular carcinoma. 1855 9

This study is to investigate the long-term effects of nanodimension PEG-PLA artificial red blood cells containing hemoglobin and red blood cell enzymes on the liver and spleen after 1/3 blood volume top loading in rats. The experimental rats received one of the following infusions: Nano artificial red blood cells in Ringer lactate, Ringer lactate, stroma-free hemoglobin, polyhemoglobin, and autologous rat whole blood. Blood samples were taken before infusions and on days 1, 7, and 21 after infusions for analysis. Nano artificial red blood cells, polyhemoglobin, Ringer lactate and rat red blood cells did not have any significant adverse effects on alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, creatine kinase, amylase and creatine kinase. On the other hand, stroma-free hemoglobin induced significant adverse effects on liver as shown by elevation in alanine aminotransferase and aspartate aminotransferase throughout the 21 days. On day 21 after infusions rats were sacrificed and livers and spleens were excised for histological examination. Nano artificial red blood cells, polyhemoglobin, Ringer lactate and rat red blood cells did not cause any abnormalities in the microscopic histology of the livers and spleens. In the stroma-free hemoglobin group the livers showed accumulation of hemoglobin in central veins and sinusoids, and hepatic steatosis. In conclusion, injected nano artificial red blood cells can be efficiently metabolized and removed by the reticuloendothelial system, and do not have any biochemical or histological adverse effects on the livers or the spleens.
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PMID:Long-term effects on the histology and function of livers and spleens in rats after 33% toploading of PEG-PLA-nano artificial red blood cells. 1904 18

The complex between manganese (Mn) porphyrins and catalase-poly(ethylene glycol) (PEG) conjugates has been designed for the protective effect against hepatic ischemia/reperfusion injury in vivo. The resulting Mn-porphyrin/catalase-PEG complex with dual enzymatic activity of superoxide dismutase (SOD) and catalase enhanced the blood circulation. The spin reduction rate in the rats treated with the Mn-porphyrin/catalase-PEG complex was significantly higher than that in the untreated rats and almost equal to that in the sham group rats. Furthermore, the Mn-porphyrin/catalase-PEG complex significantly decreased the serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels. These results suggest that the Mn-porphyrin/catalase-PEG complex exhibited the antioxidative activity to protect hepatic ischemia/reperfusion injury in vivo.
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PMID:Protective effects of the complex between manganese porphyrins and catalase-poly(ethylene glycol) conjugates against hepatic ischemia/reperfusion injury in vivo. 1916 2

It is not known whether iron depletion before pegylated IFN or combination treatment improves sustained virological response (SVR) rate in patients with chronic hepatitis C, despite its use in clinical practice in this setting. We aimed to investigate whether blood letting improves the efficacy (SVR) and tolerability of PEG-IFNalpha2b + Ribavirin in chronic hepatitis C patients. Patients with chronic hepatitis C and ferritin >100 ng/mL were randomized to: (1) repeated phlebotomies to obtain a ferritin level <50 ng/mL followed by pegylated-Interferon alpha2b + ribavirin (active arm); or (2) pegylated-Interferon alpha2b + ribavirin (control arm). Primary endpoint was SVR rate, secondary endpoint was frequency of clinical and laboratory grade 3-4 adverse events. Thirty-three patients were enrolled in the study (19 in active arm, 14 in control arm). The 19 patients in the active arm underwent a median of 5 phlebotomies (range: 1-9) to achieve the targeted ferritin (<50 ng/mL). Phlebotomies significantly reduced ferritin, iron, transferrin saturation, aspartate aminotransferase, alanine aminotransferase, and hemoglobin levels. Platelet count significantly increased, whereas HCV-RNA levels remained unchanged. After antiviral therapy overall SVR was 31.6% in active arm and 21.4% in control arm (P = 0.698). Considering only the 18 patients who were naive to antiviral therapy, SVR was 60% in active arm versus 25% in control arm (P = 0.188). Tolerability, drug dose reduction or withdrawal were similar in the two arms. In conclusion phlebotomies do not increase the overall efficacy of antiviral therapy. However, the strong trend to higher SVR in naive patients undergoing phlebotomies warrants further investigation.
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PMID:Iron depletion before HCV antiviral therapy: a pilot, randomized, controlled trial. 1976 Jul 53

The disruption of intracellular Ca(2+) homoeostasis is involved in cisplatin-induced nephrotoxicity. The role of Ca(2+) in cisplatin toxicity was studied by use of rat renal cortical slices. Cisplatin (2 mm) increased the leakage of aspartate aminotransferase (AST) from 1.4 +/- 0.5 units/g wet weight (mean +/- SE) with control slices to 3.4 +/- 0.5 units/g wet weight. The leakage of lactate dehydrogenase (LDH) was increased from 3.8 +/- 1.1 units/g wet weight to 13.7 +/- 1.0 units/g wet weight. Pretreatment of slices with ethylene glycol-bis(beta-aminoethylether)N,N,N'N'-tetraacetic acid (1 mm) to buffer intracellular Ca(2+) significantly decreased the cisplatin-induced leakage of these two enzymes to 65% and 53%, respectively, of levels with cisplatin alone. An increase in extracellular Ca(2+), or omission of Ca(2+) from the medium, had no effect on cisplatin-induced slice toxicity. Furthermore, the Ca(2+) channel blockers nifedipine and diltiazem did not protect against cytotoxicity by cisplatin, although verapamil gave mild protection and decreased the cisplatin-induced release of AST and LDH to 78% and 75%, respectively, of that caused by cisplatin alone. The results suggest that intracellular Ca(2+) is important in cisplatin-induced nephrotoxicity but that disruption of cytosolic Ca(2+) is not caused by opening of Ca(2+) channels of the plasma membrane or even by leakage through the injured membrane.
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PMID:Role of calcium in cisplatin-induced cell toxicity in rat renal cortical slices. 2065 Jan 98


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