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)

Calcium stimulated efflux of four enzymes from human rectus abdominis muscle was studied in vitro. The ratio of efflux of creatine kinase (EC2.7.3.2) increased with increasing calcium concentrations reaching a maximum level with 5mM calcium of 1.9 times that in the absence of calcium. Lactate dehydrogenase (EC 1.1.1.27) efflux at this calcium concentration increased to 2.6 times that in the absence of calcium. However, alanine aminotransferase (EC 2.6.1.2) and aspartate aminotransferase (EC 2.6.1.1) showed a slower increase in the rate of efflux in the presence of 5OmM calcium reaching levels of only 1.3 and 1.5 times respectively that in the absence of calcium. These observations suggest that calcium may be involved in augmenting enzyme efflux from human muscle and may therefore be of relevance in the pathogenesis of Duchenne muscular dystrophy.
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PMID:Calcium stimulated enzyme efflux from human skeletal muscle. 740 66

Holstein bull calves were used to determine the influence of degradable nitrogen and ration physical form on rumen epithelial transport and enzymic activity. Rations contained 30, 45 and 60% ruminal degradable nitrogen (RDN), each with three forms (ground hay, GR; chopped hay, CH; and all concentrate, CONC). Rumen tissue samples were obtained by biopsy (8 weeks) and at slaughter (20 weeks). Acetate transport across rumen epithelium increased between 8 and 20 weeks in calves fed GR and CH, but not in calves fed CONC. Propionate transport was highest in calves fed GR and lowest in calves fed CONC at both 8 and 20 weeks. Transport of acetate and propionate was incresed with increasing RDN at 20 weeks. There were no differences in ruminal tissue lactate production. Rumen papillae of calves fed CONC were abnormal in morphology and at 20 weeks dry mucosal weights (mg/cm2) were highest. Lactate dehydrogenase and NADP-malic dehydrogenase activities were not different. Propionyl CoA synthetase activity was higher in 20-week calves fed CONC, compared to GR to CH. Glutamate dehydrogenase and aspartate aminotransferase activities were highest in 20-week calves fed 60% RDN rations, regardless of physical form.
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PMID:Influence of ration physical form, ruminal degradable nitrogen and age on rumen epithelial propionate and acetate transport and some enzymatic activities. 744 67

Lactate dehydrogenase (LDH), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) concentrations and platelet counts were measured in 26 normal pregnant women and 51 preeclamptic women. In the normal-pregnancy group, no significant changes were found in the results of these tests. In the preeclampsia group, ALT and AST concentrations were not significantly higher than those in normal pregnancy, but the LDH concentrations increased and the platelet counts decreased significantly through the pregnancy. The increases in LDH did not correlate with changes in ALT or AST. Preeclamptic women with small-for-gestational-age (SGA) infants had significantly higher LDH concentrations than those in the appropriate-for-gestational-age (AGA) group, but ALT and AST concentrations did not increase significantly. As reasons for the LDH increase in our subjects, liver damage was excluded and more active glycolysis in addition to severe cell damage due to chronic anoxemia were inferred. It is suggested that an increase in LDH is predictive of SGA infants in preeclamptic pregnancy, especially in those with normal liver function.
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PMID:Increased concentrations of lactate dehydrogenase in pregnancy with preeclampsia: a predictor for the birth of small-for-gestational-age infants. 763 66

Soluble and membrane-bound aminopeptidase activities in 11 regions of the rat brain were assayed using L-Leucine-2-naphthylamide as a substrate. In addition, two metabolic enzymatic activities were compared: lactate dehydrogenase and aspartate aminotransferase. All enzymatic activities showed significant regional differences when the data were analyzed statistically. Soluble aminopeptidase and aspartate aminotransferase activities were significantly lower in cortical than in subcortical areas. Membrane-bound aminopeptidase activity levels were higher in cortical areas. Lactate dehydrogenase activities did not differ between cortical areas and the rest of the zones studied. However, although no wide regional differences were found for the other enzymatic activities, membrane-bound aminopeptidase varied markedly across brain regions: a fivefold difference was observed between zones such as parietotemporal cortex and medulla. The differential distribution of this enzymatic activity is consistent with the hypothesis that it could be responsible for the enzymatic inactivation of some neuroactive peptides.
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PMID:Regional distribution of soluble and membrane-bound aminopeptidase activities in rat brain. 849 Jul 37

The objective of this review is to provide an overview of the use of biochemical markers for the detection of Central Nervous System (CNS) complications after cardiac surgery and extracorporeal circulation (ECC). A computerized literature search in MEDLINE from 1966 onward was the basis for the references. The literature covering the following biochemical markers is reviewed: adenylkinase, creatine phosphokinase isoenzyme BB (CK-BB), lactate, neuron-specific enolase (NSE), S-100 protein, myelin basic protein, lactate dehydrogenase, aspartate aminotransferase, glutathione, vasointestinal neuropeptide, and 7B2-specific neuropeptide. For clinical purposes, it is necessary to have a biochemical marker that can be measured in blood. Lactate, although a primary marker of anaerobic metabolism, and CK-BB values, calculated from the arterio-internal jugular venous difference, appear to correlate with periods of ischemia during ECC. S-100 protein levels have been shown to correlate with duration of ECC, and when combined with NSE values, could be used to identify patients with CNS dysfunction after cardiac surgery. The use of NSE may be limited by its presence in erythrocytes and platelets because the high levels that can result from hemolysis can render it less specific. Although recently introduced, S-100 protein may have the potential to be a valuable marker for CNS dysfunction after ECC.
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PMID:Markers of cerebral ischemia after cardiac surgery. 863 77

In a randomised, double-blind placebo-controlled trial, the effects of the administration of oral L-carnitine (2 g/day) for 28 days were compared in the management of 51 (carnitine group) and 50 (placebo group) patients with suspected acute myocardial infarction. At study entry, the extent of cardiac disease, cardiac enzymes and lipid peroxides were comparable between the groups, although both groups showed an increase in cardiac enzymes and lipid peroxides. At the end of the 28-day treatment period, the mean infarct size assessed by cardiac enzymes showed a significant reduction in the carnitine group compared to placebo. Electrocardiographic assessment of infarct size revealed that the QRS-score was significantly less in the carnitine group compared to placebo (7.4 +/- 1.2 vs 10.7 +/- 2.0), while serum aspartate transaminase and lipid peroxides showed significant reduction in the carnitine group. Lactate dehydrogenase measured on the sixth or seventh day following infarction showed a smaller rise in the carnitine group compared to placebo. Angina pectoris (17.6 vs 36.0%), New York Heart Association class III and IV heart failure plus left ventricular enlargement (23.4 vs 36.0%) and total arrhythmias (13.7 vs 28.0%) were significantly less in the carnitine group compared to placebo. Total cardiac events including cardiac deaths and nonfatal infarction were 15.6% in the carnitine group vs 26.0% in the placebo group. It is possible that L-carnitine supplementation in patients with suspected acute myocardial infarction may be protective against cardiac necrosis and complications during the first 28 days.
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PMID:A randomised, double-blind, placebo-controlled trial of L-carnitine in suspected acute myocardial infarction. 874 85

The cyanobacterial hepatotoxin, microcystin-LR (MCLR), is a potent protein phosphatase inhibitor that disrupts actin microfilament, cytokeratin intermediate filament, and microtubule networks in hepatocytes. To determine ultrastructural and biochemical changes that develop concurrently with microcystin-induced cytoskeletal disorganization, isolated rat livers were perfused with MCLR at 0.1 to 5.0 micrograms/ml for 5 to 40 min. Lactate dehydrogenase, alanine aminotransferase, and aspartate aminotransferase changed over time, but trends for toxin-treated and control livers did not differ. The earliest toxin-induced ultrastructural changes, observed in livers perfused at 0.1 microgram/ml for 15-20 min or at 0.3 microgram/ml for 5-10 min, were loss of hepatocyte microvilli in the space of Disse, widening of sinusoidal fenestrae, disruption of sinusoidal endothelium, dilation of bile canaliculi with loss of microvilli, and widening of hepatocyte intercellular spaces. Lesions progressed with increasing toxin concentrations and exposure times. In livers perfused with MCLR at 0.5 microgram/ml for 10-20 min, hepatocytes had plasma membrane blebs and concentric whorls of rough endoplasmic reticulum, and there was marked disassociation of hepatocytes resulting in disrupted hepatic cords. At toxin concentrations of 2.0 or 5.0 micrograms/ml for 10-20 min, there was mild dilation of mitochondrial cristae, cytoplasmic vacuolization or invagination of plasma membranes, redistribution of organelles, and sometimes nuclear degenerative change. Some hepatocytes exhibited clusters of plasma membrane blebs radiating from round cytoplasmic structures, which may be composed primarily of condensed microfilaments.
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PMID:Sequential ultrastructural and biochemical changes induced by microcystin-LR in isolated perfused rat livers. 894 94

The possibility that postmortem biochemical changes in blood might parallel drug redistribution and thus serve as markers was explored in a detailed case study. Eighteen blood and 14 tissue and fluid samples were taken at autopsy 16 h after the death of a 34-year-old female from amitriptyline overdose. Ranges of drug concentrations in blood were amitriptyline 1.8 to 20.2 micrograms/mL, nortriptyline 0.6 to 7.3 micrograms/mL, levels were lowest in femoral vein and highest in pulmonary vein blood. Corresponding levels of 17 amino acids showed markedly different patterns of site-to-site variability. There was a strong positive correlation between individual amino acid and drug concentrations in pulmonary blood samples (n = 5), particularly for glycine, leucine, methionine, serine, and valine. In blood samples from the great veins and right heart (n = 10), the correlation was less strong (r = 0.6 to 0.7). Methionine showed a strong positive correlation in pulmonary samples (r = 0.93), and negative correlation in great veing samples (r = -0.68). Lactic acid showed a strong negative correlation in pulmonary samples (r = -0.93) but a positive correlation in great vein samples (r = 0.71). Alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, gamma-glutamyl transferase, glucose, and bilirubin had a weak positive correlation with drug levels in great vein samples but not pulmonary samples. The results suggest that hepatic enzymes are relatively poor markers for postmortem hepatic drug shifts but that amino acids, particularly methionine, may be useful markers for pulmonary drug shifts.
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PMID:Possible markers for postmortem drug redistribution. 898 78

Lactate dehydrogenase (LDH) and aspartate aminotransferase (AST) activities and total protein concentrations were examined in the postrinsing solutions from rat lungs preserved in phosphate-buffered saline (PBS), Euro-Collins (E-C) solution, or low-potassium E-C solution for 8 h at 4 degrees C, 10 degrees C, or 20 degrees C. The LDH and AST activities were higher when the organs were preserved in PBS for 8 h at 20 degrees C than at 4 degrees C or 10 degrees C, while the total protein concentration did not differ according to the temperature or solution. The activities were also higher when the lungs were preserved in Euro-Collins (E-C) solution than in PBS or the low-potassium E-C solution. On examining pulmonary functions utilizing an ex vivo reperfusion model, the lungs preserved at 20 degrees C showed poorer gas exchange than those preserved at 4 degrees C or 10 degrees C. Moreover, the organs preserved in E-C solution showed poorer function than those preserved in any other solution. These findings suggest that some enzymatic activities in the postrinsing solution could be indicators of lung viability after preservation.
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PMID:Functional and biochemical evaluation of the preserved lung in a rat model. 901 70

Medium osmolarity sensitively regulates Kupffer cell functions like phagocytosis and prostaglandin (PG) and cytokine production. Betaine and taurine, recently identified as osmolytes in liver cells, interfere with these effects. Because Kupffer cell activation is an important pathogenic mechanism in ischemia-reoxygenation injury, the influence of osmolarity and osmolytes was investigated in a rat liver perfusion model of warm ischemia. Livers were perfused with different medium osmolarities for 60 to 90 minutes in the absence of oxygen, followed by another 90 minutes of reoxygenation. Lactate dehydrogenase (LDH) leakage into the effluent perfusate during the hypoxic and the reoxygenation period was eight- to 10-fold higher with a medium osmolarity of 385 mosmol/L than in normo-osmolarity, and further decreased with hypo-osmolar perfusion buffer. Betaine and taurine addition to the perfusate in near physiological concentrations decreased hypoxia-reoxygenation-induced LDH leakage, aspartate transaminase (AST) leakage, and perfusion pressure increase in hyperosmolar and normo-osmolar perfusions. Stimulation of PGD2, PGE2, thromboxane B2 (TXB2), and tumor necrosis factor alpha (TNF-alpha) release, as well as induction of carbon uptake by the liver during reoxygenation, were suppressed by betaine and taurine, pointing to an interference of these osmolytes with Kupffer cell function. In contrast, endothelial cell function as assessed by hyaluronic acid (HA) uptake was not influenced. It is concluded that warm ischemia-reoxygenation injury in rat liver is aggravated by hyperosmolarity and attenuated by hypo-osmolarity. The osmolytes betaine and taurine have a protective effect, presumably by inhibition of Kupffer cell activation.
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PMID:Cytoprotection by the osmolytes betaine and taurine in ischemia-reoxygenation injury in the perfused rat liver. 939 98


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