Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.6.1.2 (alanine aminotransferase)
 26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In order to evaluate the pathogenetic role of iron in Porphyria cutanea tarda (PCT), the metabolism of iron was studied in 440 patient with PCT and associated chronic liver disease (CLD) and in 91 nonporphyric CLD patients (used as a control group). The parameters considered were the following: serum iron, ferritin, Total Iron Binding Capacity (TIBC) and percent saturation of transferrin. The statistical analysis showed that the differences between the means, in the two groups, were not significant in any of the parameters examined. To investigate the possible relationships between iron metabolism and other chemico-clinical parameters concerning the porphyric disease, the associated hepatic disease and hemometry, we studied the correlations between iron parameters and total urinary and serum porphyrins, serum copper, serum albumin, hemoglobin, red blood cells, ALT, AST, CHE and GLDH. This investigation was only possible in the last 99 cases. In addition to the obvious correlations between the parameters concerning iron metabolism, the highly significant (p < 0.001) correlation between ferritin and enzyme activities which indicate cytolysis (ALT, AST, GLDH) is extremely interesting. The results seem to point to the tentative conclusion that the alterations of iron metabolism are more related to the hepatocellular necrosis than to the metabolism of porphyrins.
Cell Mol Biol (Noisy-le-grand) 1997 Feb
PMID:Iron and porphyria cutanea tarda. 907 91

According to the telomere hypothesis of senescence, the progressive shortening of telomeres that occurs upon division of normal somatic cells eventually leads to cellular senescence. The immortalisation of human cells is associated with the acquisition of a telomere maintenance mechanism which is usually dependent upon expression of the enzyme telomerase. About one third of in vitro immortalised human cell lines, however, have no detectable telomerase but contain telomeres that are abnormally long. The nature of the alternative telomere maintenance mechanism (referred to as ALT, for Alternative Lengthening of Telomeres) that must exist in these telomerase-negative cells has not been elucidated. It has previously been shown that abnormal lengthening of yeast telomeres may occur due to mutations in the yeast telomerase RNA gene. That this is not the mechanism of the abnormally long telomeres in ALT cell lines was demonstrated by the finding that seven of seven ALT lines have wild-type human telomerase RNA (hTR) sequence, including a novel polymorphism that is present in 30% of normal individuals. We found that two ALT cell lines have no detectable expression of the hTR gene. This shows that the ALT mechanism in these cell lines is not dependent on hTR. Expression of exogenous hTR via infection of these cells with a recombinant hTR-adenovirus vector did not result in telomerase activity, indicating that their lack of telomerase activity is not due to absence of hTR expression. We conclude that the ALT mechanism is not dependent on the expression of hTR, and does not involve mutations in the hTR sequence.
Hum Mol Genet 1997 Jun
PMID:The telomere lengthening mechanism in telomerase-negative immortal human cells does not involve the telomerase RNA subunit. 917 40

Effects of acute physical exercise on the acetaminophen-induced hepatotoxicity were examined in adult female rats. Rats were forced to move at a speed of 10 m/min for 2 hr in a rotating cage. Immediately following the exercise bout rats were treated with acetaminophen (APAP; 700 mg/kg, i.p.). The physical exercise enhanced the hepatotoxicity of APAP as shown by increases in alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities measured 24 hr following the treatment. A significant decrease in hepatic glutathione (GSH) was observed in the rats forced to exercise suggesting that the enhancement of APAP hepatotoxicity was associated with the depression of this endogenous tripeptide. The role of adrenergic stimulation in the exercise-induced hepatic GSH depression was examined by pretreating the animals with a receptor specific adrenergic antagonist, such as prazosin HCl (15 mg/kg, i.p.), propranolol HCl (15 mg/kg, i.p.), and yohimbine HCl (15 mg/kg, i.p.) 15 min prior to the exercise bout, but neither of the antagonists prevented the GSH depression. Administration of alpha-tocopherol acetate (450 mg/kg/day for 3 days and 150 mg/kg on day 4, i.p.) did not affect the exercise-induced GSH depression or lipid peroxidation in liver homogenates as determined by increases in malondialdehyde formation. These results suggest that neither adrenergic stimulation nor oxidative stress plays a significant role in the enhancement of APAP hepatotoxicity and hepatic GSH depression induced by acute physical exercise.
Res Commun Mol Pathol Pharmacol 1997 Apr
PMID:Potentiation of acetaminophen hepatotoxicity by acute physical exercise in rats. 917 66

Isolation and cloning of abundant reverse transcriptase-polymerase chain reaction (RT-PCR) products from the filarial nematode Brugia malayi using the conserved nematode spliced leader sequence and poly A as amplification targets has allowed us to identify abundant, stage specific transcripts from infective and post-infective larvae. The predicted protein products of the most prominent full-length transcripts from mosquito-derived L3 parasites are: (i) Bm-ALT-1, a homologue of a Dirofilaria immitis abundant larval protein: (ii) Bm-CPI-1, a cystatin-type cysteine protease inhibitor; (iii) Bm-ALT-3, a novel predicted 6 kDa glycine/tyrosine-rich protein; and (iv) Bm-TPH-1, a homologue of a mammalian translationally-controlled tumour protein. Some transcripts were not full-length but had mis-primed at A-rich stretches of coding sequence: the most abundant of these was Bm-col-3, a which encodes a collagen homologous to Bp-COL-1 of Brugia pahangi. Similar analysis of abundant spliced leader (SL)/oligo-dT products from fourth-stage larvae 9 days post-infection yielded two dominant transcripts: (i) Bm-cdd-1, which encodes a protein with homology to cytidine deaminase, differing at only one amino acid position from its homologue described in Brugia pahangi; and (ii) the same truncated form of Bm-col-3 found in L3 preparations. Expression of the major transcripts was assessed by PCR amplification of cDNA libraries derived from each stage of the life cycle. alt1, alt-3 and cpi-1 were all found to be specific to the L3 stage, while cdd-1 was found only in the L4 cDNA library. Expression of these larval-specific transcripts was not detected in either microfilarial or adult libraries.
Mol Biochem Parasitol 1997 Jul
PMID:Differentially expressed, abundant trans-spliced cDNAs from larval Brugia malayi. 923 76

The regulation of phosphoinositide hydrolysis by the type 1alpha metabotropic glutamate receptor (mGluR1alpha) was investigated in stably transfected baby hamster kidney (BHK) cells. Incubation of the cells with L-glutamate, quisqualate, and 1-aminocyclopentane-1S, 3R-dicarboxylic acid resulted in a marked accumulation of [3H]inositol monophosphate (InsP1) and inositol-1,4,5-trisphosphate [Ins(1,4,5)P3] mass in a time- and concentration-dependent manner. Pretreatment of BHK-mGluR1alpha cells with pertussis toxin [ 100 ng/ml, 24 hr] led to a dramatic 12-16-fold increase in the accumulation of [3H]InsP1 and a 2-fold increase in Ins(1,4,5)P3 in the absence of added agonist. Although only very low levels (</=1 microM) of L-glutamate could be detected in medium taken from control and PTX-treated cell monolayers, the PTX-elicited effect on basal [3H]InsP1 was fully reversed by preincubation of cells in the presence of glutamic-pyruvic transaminase and pyruvate, suggesting that an increased sensitivity to endogenous glutamate was responsible for the apparent agonist-independent activation of phosphoinositidase C (PIC) after PTX treatment. Consistent with this hypothesis, in the presence of glutamic-pyruvic transaminase/pyruvate, the maximal [3H]InsP1 response to quisqualate was increased by >/=75%, and the EC50 shifted leftward by 65-fold [-log EC50 values (molar), 7.26 +/- 0.23 versus 5.45 +/- 0.07; n = 4) in PTX-treated compared with control cells. In contrast, antagonist effects on agonist-stimulated [3H]InsP1 responses were similar in control and PTX-treated BHK-mGluR1alpha cells. These changes in the concentration-effect curves for mGluR agonists are consistent with a model in which the receptor associates with PTX-sensitive inhibitory (Gi/o) and PTX-insensitive stimulatory (Gq/11) G proteins that can each influence PIC activity. The present observations are consistent with a dual regulation of mGluR1alpha-mediated PIC activity that could be fundamental in controlling the output of phosphoinositide-derived messengers.
Mol Pharmacol 1997 Sep
PMID:Enhanced type 1alpha metabotropic glutamate receptor-stimulated phosphoinositide signaling after pertussis toxin treatment. 928 2

Isolated perfused livers from rats fasted 16 h before surgery showed a strong decrease in oxygen consumption as well as hepatotoxic responses when subjected to 30 min of hypoxia (95%, N2/5% CO2) followed by 90 min of reoxygenation (95% O2/5% CO2). Toxicity was evident by a release of enzymes (LDH, GPT, GLDH) into the perfusate and by a nearly complete suppression of bile flow. Hepatic reduced gluthathione dropped to about 20% and hepatic ATP to about 50% of the initial values. Furthermore, the concentrations of thiobarbituric acid reactive (TBA) material increased eightfold in the perfusate and by 70% of the control values in the livers. Glycine added to the perfusate at concentrations of 3, 6 and 12 mmol/l prevented dose-dependently all measures of hepatotoxicity as well as the indices of lipid peroxidation induced by hypoxia/reoxygenation. A maximal and nearly complete protection was obtained with 12 mmol/l glycine. Glycine increased the bile flow of perfused livers not subjected to hypoxia and attenuated the drop of bile flow induced by hypoxia-reoxygenation. Ligation of the bile duct, however, did not influence the cytoprotective effects of glycine in hypoxia-reoxygenation induced hepatic injury. In conclusion, glycine is an effective antidote against hypoxia-regoxygenation induced injury of the isolated rat liver.
Res Commun Mol Pathol Pharmacol 1997 Aug
PMID:Protection by glycine against hypoxia-reoxygenation induced hepatic injury. 934 32

The possible relation of the increase in the concentration of copper (Cu) in the bloodstream with the increased supply of Cu to ceruloplasmin in the liver was examined in relation to the onset of jaundice in Long-Evans rats with a cinnamon-like coat color (LEC rats), an animal model of Wilson disease. The Cu concentration in serum and that in liver, and then that in kidneys of LEC rats were correlated, and then the relationship between the Cu concentration in serum and the malondialdehyde (MDA) concentration in the liver, a marker for lipid peroxidation, and also the activities of alanine aminotransferase and lactate dehydrogenase, marker enzymes for liver damage, were examined. An increase in the Cu concentration in liver induced significant increases in the Cu concentrations in serum and kidneys, and their relationship was different before and after the onset of jaundice, as reflected by the concentration of Cu in serum (lower than 1.5 and higher than 2.7 micrograms/ml, respectively). The relationship between the MDA concentration in liver and the Cu concentration in serum showed a characteristic change between before and after the onset of jaundice. The marker enzymes for liver damage increased significantly with age, and showed distinct responses at the Cu concentration of 1.5-2.7 micrograms/ml in serum. The results suggest that the Cu concentration in plasma reflects the on-going biological and toxicological actions of non-MT-bound Cu in the livers of LEC rats.
Res Commun Mol Pathol Pharmacol 1997 Dec
PMID:Copper in plasma reflects its status and subsequent toxicity in the liver of LEC rats. 948 27

The protective effects of alpha-Hederin on carbon tetrachloride-induced hepatotoxicities were investigated in mice. Pretreatment with alpha-Hederin prior to the administration of carbon tetrachloride significantly prevented the increase in serum alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) activity and lipid peroxidation in a dose dependent manner. Hepatic glutathione levels and glutathione-S-transferase activities were not affected by pretreatment with alpha-Hederin alone but pretreatment with alpha-Hederin protects carbon tetrachloride-induced depletion of hepatic glutathione levels. The effects of alpha-Hederin on the cytochrome P450 (P450) 2E1, the major isozyme involved in carbon tetrachloride bioactivation were investigated. alpha-Hederin markedly decreased the P450 2E1-specific activities of p-nitrophenol and aniline hydroxylation in a dose-dependent manner. Consistent with these observations, the P450 2E1 expressions were also decreased, as determined by immunoblot analysis. These results demonstrate that treatment of mice with alpha-Hederin decreases the expression and activities of P450 2E1 enzyme, and reduces biotransformation of carbon tetrachloride, and diminished carbon tetrachloride-induced liver injury.
Biochem Mol Biol Int 1998 Jun
PMID:The prevention of carbon tetrachloride-induced hepatotoxicity in mice by alpha-hederin: inhibiton of cytochrome P450 2E1 expression. 963 40

Male albino rats were intramuscularly administered a single dose of lead acetate (100 micromol/kg b.wt). Another group of rats were injected with sodium selenite (10 micromol/kg b.wt) before lead intoxication. After 3 and 24 hours, lead treatment resulted in significant increases in acid and alkaline phosphatases, GOT and GPT, total proteins, and cholesterol in serum. The total triglycerides in serum was decreased after 24 hours of intoxication. Lead treatment also produced significant elevation of lipid peroxidation in liver and kidney. The antioxidant capacity of hepatic and renal cells in terms of the activities of superoxide dismutase, glutathione reductase, and glutathione content was diminished. It appears from these results that lead may exert its toxic effect via peroxidative damage to renal and hepatic cell membranes after 24 hours. Selenium administration prior to lead injection produced pronounced prophylactic action against lead effects, and it is observed that selenium enhances the endogenous antioxidant capacity of the cells by increasing the activities of the superoxide dismutase and glutathione reductase and the glutathione content. As a result, the lipid peroxidation was decreased in both liver and kidney.
J Biochem Mol Toxicol 1998
PMID:Role of selenium against lead toxicity in male rats. 973 83

The Fas ligand (FasL), a member of the tumor necrosis factor family, induces apoptosis in Fas-expressing cells. A matrix metalloproteinase-like enzyme cleaves the membrane-bound FasL to produce the soluble FasL (sFasL). Since FasL has been reported to play a pivotal role in the development of hepatitis, we evaluated clinical significance of serum sFasL in acute liver injury including acute self-limited and fulminant hepatitis. Serum sFasL in 19 patients including 12 with acute self-limited hepatitis and 7 with fulminant hepatitis was measured by an enzyme-linked immunosorbent assay (ELISA). The clinical data consisted of 18 indices including age, sex, liver function tests, hepatocyte growth factor (HGF), outcome and sFasL. Serum sFasL in fulminant hepatitis is 0.06+/-0.01 ng/ml, being identical to that in acute self-limited hepatitis, Serum sFasL is positively correlated with AST and ALT (p<0.0001 and p<0.0001). The factors associated with outcome of the patients were HGF, albumin, prothrombin time, platelet count, cholinesterase and leukocyte count in this order. Serum sFasL serves as an indicator of liver injury in acute self-limited and fulminant hepatitis.
Res Commun Mol Pathol Pharmacol 1998 Jul
PMID:Clinical significance of serum soluble Fas ligand in patients with acute self-limited and fulminant hepatitis. 975 39


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