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 serum concentrations of CA19-9 and carcinoembryonic antigen (CEA) were measured in 150 consecutive patients with histologically proven liver disease admitted to a liver unit for transplant assessment. A significant proportion of the cases studied had a CA19-9 above the upper limit of the reference range (35 kU/L): alcoholic liver disease (73%), primary sclerosing cholangitis (61%), primary biliary cirrhosis (60%), chronic hepatitis B (71%), chronic hepatitis C (84%), autoimmune hepatitis (36%) and hepatocellular carcinoma (54%). CEA was only elevated in a small proportion of the patients with benign liver disease and the degree of elevation was small (15-37 micrograms/L). Significantly raised CEA was observed in two patients (15%) with hepatocellular carcinoma. Statistically significant correlations were observed between the serum CA19-9 concentration and standard parameters of liver dysfunction: positive correlations with aspartate aminotransferase, alkaline phosphatase and bilirubin and negative correlations with albumin and gamma-glutamyltransferase. Positive relationships were also observed between CA19-9 and both CEA and creatinine. Both increased production of CA19-9 from biliary epithelial cells and decreased clearance due to cholestasis may be contributing to the elevation of CA19-9 in the bloodstream. Our data indicate that caution is needed in the interpretation of CA19-9 results in the presence of liver dysfunction.
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PMID:The effect of benign and malignant liver disease on the tumour markers CA19-9 and CEA. 946 46

To explain the increased plasma mitochondrial aspartate aminotransferase (mAspAT) observed in alcoholics, we cultured HepG2 hepatoma cells in ethanol. Acute (24 hour) exposure to 0, 20, 40, or 80 mmol/L ethanol produced a dose-dependent (r = .98) increase in mAspAT messenger RNA (mRNA) of < or = thirteen-fold, with no significant change in the cellular content of mAspAT or of several other enzymes. The recovery of mAspAT in the medium over 24 hours of ethanol exposure correlated with both ethanol concentration and with mAspAT mRNA (r = .90), reaching 808% of cellular enzyme content/24 hours at 80 mmol/L. Recovery of all other enzymes studied was < or = 20% of cellular content and unaffected by ethanol. Plasma membrane mAspAT content also correlated with mAspAT mRNA (r = .96) and mitochondrial levels were unchanged. No mitochondrial morphologic abnormalities were observed at any ethanol concentration studied. In cells cultured chronically at 0 to 80 mmol/L ethanol, fatty acid uptake Vmax increased in parallel with plasma membrane expression of mAspAT (r = .98). Cellular triglyceride content was highly correlated with Vmax. Thus, the data suggest that: 1) the increased plasma mAspAT observed in alcoholics may reflect pharmacologic upregulation of mAspAT mRNA and of mAspAT synthesis by ethanol; and 2) increased mAspAT-mediated fatty acid uptake may contribute to alcoholic fatty liver.
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PMID:Ethanol up-regulates fatty acid uptake and plasma membrane expression and export of mitochondrial aspartate aminotransferase in HepG2 cells. 953 59

Regulation of gene expression of three putative long-chain fatty acid transport proteins, fatty acid translocase (FAT), mitochondrial aspartate aminotransferase (mAspAT), and fatty acid transport protein (FATP), by drugs that activate peroxisome proliferator-activated receptor (PPAR) alpha and gamma were studied using normal and obese mice and rat hepatoma cells. FAT mRNA was induced in liver and intestine of normal mice and in hepatoma cells to various extents only by PPARalpha-activating drugs. FATP mRNA was similarly induced in liver, but to a lesser extent in intestine. The induction time course in the liver was slower for FAT and FATP mRNA than that of an mRNA encoding a peroxisomal enzyme. An obligatory role of PPARalpha in hepatic FAT and FATP induction was demonstrated, since an increase in these mRNAs was not observed in PPARalpha-null mice. Levels of mAspAT mRNA were higher in liver and intestine of mice treated with peroxisome proliferators, while levels in hepatoma cells were similar regardless of treatment. In white adipose tissue of KKAy obese mice, thiazolidinedione PPARgamma activators (pioglitazone and troglitazone) induced FAT and FATP more efficiently than the PPARalpha activator, clofibrate. This effect was absent in brown adipose tissue. Under the same conditions, levels of mAspAT mRNA did not change significantly in these tissues. In conclusion, tissue-specific expression of FAT and FATP genes involves both PPARalpha and -gamma. Our data suggest that among the three putative long-chain fatty acid transporters, FAT and FATP appear to have physiological roles. Thus, peroxisome proliferators not only influence the metabolism of intracellular fatty acids but also cellular uptake, which is likely to be an important regulatory step in lipid homeostasis.
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PMID:Expression of putative fatty acid transporter genes are regulated by peroxisome proliferator-activated receptor alpha and gamma activators in a tissue- and inducer-specific manner. 964 25

Cytosolic aspartate aminotransferase (cAspAT) participates in gluconeogenesis in the liver and is expected to exert a glyceroneogenic function in the adipose tissue when the supply of glucose is limited. Here we demonstrate that adipose cAspAT messenger RNA (mRNA) is increased when rats are fed a low carbohydrate diet. In the 3T3-F442A, BFC-1 adipocyte cell lines and differentiated adipocytes in primary culture, a 24 h glucose deprivation induces approximately a 4-fold increase in cytosolic AspAT (cAspAT) mRNA, whereas mitochondrial AspAT mRNA remains unchanged. cAspAT activity is also increased in a weaker but reproducible manner. Addition of glucose within a physiological range of concentrations reverses the increase of cAspAT mRNA in 8 h (EC50 = 1.25 g/liter). Such a regulation requires protein synthesis and is specific for adipocytes differentiated in culture. It does not occur in Fao or H4IIE hepatoma cells, in C2 muscle cells, or in 293 kidney cells. 2-deoxyglucose mimicks glucose, while 3-orthomethyl-glucose has no effect, suggesting that glucose-6-phosphate is the effector. cAspAT mRNA stability is not affected by glucose deprivation. To ascertain the transcriptional nature of the glucose effect, we have stably transfected 3T3-F442A adipoblasts with constructs containing the chloramphenicol acetyltransferase reporter gene under the control of either 5'-deletions of the cAspAT gene promoter or internal fragments in an heterologous context. We demonstrate that a glucose response element(s) is present in the region between -1838 and -1702 bp relative to the translation start site. In this region, three DNA sequences bind nuclear proteins from adipocytes as shown by footprinting experiments. Our results indicate that cAspAT gene transcription is repressed by glucose selectively in adipocytes.
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PMID:Identification of an adipocyte-specific negative glucose response region in the cytosolic aspartate aminotransferase gene. 983 31

Percutaneous transhepatic portal vein embolization (PTPE) produces regenerative hypertrophy in the nonembolized part of the liver, but the regenerative capacity after PTPE in patients with chronic hepatitis is unknown. We studied 34 patients with hepatocellular carcinoma and chronic hepatitis who underwent PTPE at the right portal vein. Hepatic lobular volumes were calculated by computed tomography before and 2 weeks after PTPE. The increase in left lobular volume was analyzed using a stepwise multiple regression method incorporating 11 factors: age; portal venous pressure; proportional volume of the right lobe; indocyanine green retention test; platelet count; serum levels of aspartate transaminase, alanine transaminase, total bilirubin, and albumin; and histological inflammatory grade and stage of fibrosis, according to the criteria of the International Association for the Study of the Liver recommended at their 1994 meeting. The median volume of the left lobe had increased from 405 to 554 cm3 (P < 0.0001) by 2 weeks after PTPE. Inflammatory grade was the only independent factor predicting regenerative hypertrophy (regeneration ratio (%) = 80.3 - 20.1 x grade; standard correlation coefficient = -0.566; P = 0.0014). Histological inflammatory activity was the essential factor regulating liver regeneration after PTPE in patients with chronic hepatitis.
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PMID:Influence of histological inflammatory activity on regenerative capacity of liver after percutaneous transhepatic portal vein embolization. 1020 30

The inbred mutant strains of Long-Evans Cinnamon (LEC) rats spontaneously develops acute hepatitis as a result of abnormal copper accumulation, followed by chronic hepatitis, cholangiofibrosis and hepatocellular carcinoma. To shed some light on the role of macrophages in the liver failure, immunohistochemical methods were used to investigate the kinetics of macrophage populations in the liver of male LEC rats, in relation to the appearance of myofibroblastic cells and hepatocyte apoptosis. Rats examined at 24 weeks of age and moribund rats killed at 22-25 weeks of age had increased serum concentrations of aspartate aminotransferase and alanine aminotransferase, with jaundice and histological changes indicative of hepatic failure, whereas rats examined at 8, 12, 16 or 20 weeks old showed no such abnormal findings. Immunolabelling with ED1 (a monoclonal antibody recognizing rat macrophages) and ED2 (a monoclonal antibody specific for rat resident macrophages) revealed that numbers of blood monocyte-derived macrophages and Kupffer cells began to increase markedly at 16 weeks of age (before the onset of hepatitis). However, alpha-smooth muscle actin (SMA)-positive myofibroblastic cells (modulated perisinusoidal cells) and hepatocyte apoptosis, demonstrable by the TUNEL method, were rarely seen at 8, 12, 16, 20 or 24 weeks. There was no close relationship between macrophage expansion and the appearance of myofibroblastic cells or hepatocyte apoptosis. In moribund rats, only a few SMA-positive cells were seen in the periportal zones; hepatocytes undergoing apoptosis increased in number, and macrophages engulfing apoptotic bodies were observed occasionally, suggesting that apoptosis was related to hepatic failure as an early event. In addition, immunohistochemical examination demonstrated abnormal deposits of laminin along the sinusoids from 20 weeks, as an initial extracellular matrix protein in LEC rat livers.
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PMID:Macrophage populations and apoptotic cells in the liver before spontaneous hepatitis in Long-Evans Cinnamon (LEC) rats. 1020 30

Aflatoxin B1 is an important consideration in the aetiology of human and animal hepatocellular carcinoma. The influence of the drug, Semecarpus anacardium Linn. nut extract, on hepatocarcinogenicity of aflatoxin B1 was evaluated in adult albino male Wistar rats. Aflatoxin B1 was administered intraperitoneally to induce hepatocellular carcinoma. These cancer bearing animals were treated with Semecarpus anacardium Linn. nut extract (200 mg/kg body weight/day) in sunflower oil orally for 14 days. The plasma and the liver tumour tissue were investigated biochemically for lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and gamma-glutamyl transpeptidase. The elevation of plasma concentration of these enzymes were indicative of the persistent deteriorating effect of aflatoxin B1 in cancer bearing animals. Lactate dehydrogenase and aminotransferases levels were decreased in liver, whereas alkaline phosphatase and gamma-glutamyl transpeptidase were increased in cancer conditions. These enzyme levels were reversed to near normal control values in drug treated animals. The analysis of marker enzyme activities clearly indicates the antitumour efficacy of Semecarpus anacardium Linn. nut extract on aflatoxin B1 induced hepatocellular carcinoma.
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PMID:Anticancer potency of the milk extract of Semecarpus anacardium Linn. nuts against aflatoxin B1 mediated hepatocellular carcinoma bearing Wistar rats with reference to tumour marker enzymes. 1035 53

An 82-year-old male patient was admitted for liver dysfunction. Laboratory test showed the following data; aspartate aminotransferase (AST) 79 IU/l, alanine aminotransferase (ALT) 28 IU/l, total bilirubin (T. Bil) 0.9 U, zinc sulfate turbidity test (ZTT) 48.9 U, gamma-globulin 4.9 g/dl, immunoglobulin G (IgG) 5,046 mg/dl, anti-nuclear antibodies x 320, anti-mitochondrial antibodies (-), hepatitis B virus surface antigen (HBsAg) (-), HBcAb (-), anti-hepatitis C virus (anti-HCV) (-), hepatitis C virus (HCV-RNA) (-), anti-hepatitis G virus (anti-HGV) (-), alpha-fetoprotein 306.8 ng/ml, carcinoembryonic antigen (CEA) 2.3 ng/ml, carbohydrate antigen (CA) 19-9 77.2 U/ml. Abdominal ultrasonography and computed tomography showed a large mass occupying most of the right lobe and portal thrombosis in the liver. Liver biopsy revealed cirrhosis with inactive hepatitis in the nontumorous lesion and well-differentiated hepatocellular carcinoma in the tumorous lesion. We report a rare case of an aged male patient with autoimmune hepatitis complicated by hepatocellular carcinoma.
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PMID:An aged male patient with autoimmune hepatitis complicated by hepatocellular carcinoma. 1039 80

Expression of the rat cytosolic aspartate aminotransferase gene is stimulated by glucocorticoids and repressed by insulin in the liver. The regulation by insulin and part of the glucocorticoid effect are mediated by a distal region in the promoter. A 142 bp fragment (-1844 to -1702) confers hormonal sensitivity to the heterologous thymidine kinase promoter in transient-transfection assays in H4IIEC3 hepatoma cells. Footprinting and gel-shift assays showed that several nuclear proteins bind to this region at conserved CCAAT-enhancer binding protein (C/EBP), activator protein (AP-1) and E-box sequences. Hepatocyte nuclear factor-3alpha (HNF-3)alpha and beta bind to sequences upstream of a glucocorticoid-responsive element (GRE) half-site as demonstrated by supershift experiments. Nuclear factor I (NFI)-like proteins bind downstream of the GRE half-site. These sites around the GRE motif overlap with five insulin responsive element (IRE) -like sequences (TG/ATTT). The effect of insulin was not prevented by any single mutation in the IRE-like sites. However, mutation of two IRE sites (namely IREc and d) prevented the insulin effect although only marginally affecting the glucocorticoid effect. The results suggest that the effect of insulin is due to a complex interplay of factors requiring the synergistic contribution of at least two sites and underline the contribution of HNF-3 and NFI-like proteins.
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PMID:Delineation of the insulin-responsive sequence in the rat cytosolic aspartate aminotransferase gene: binding sites for hepatocyte nuclear factor-3 and nuclear factor I. 1052 50

Elevated serum transaminase levels of dengue patients indicate the possible impact of dengue virus infection on liver function. To elucidate the action of dengue virus infection in liver cells, an in vitro cell line system was established that mimicked the liver status of diverse clinical patients. Briefly, four hepatoma cell lines (HA22T, Huh7, Hep3B, and PLC) and one nonmalignant hepatocyte cell line (Chang liver) were included, representing various levels of tumorigenicity and differentiation. Our data showed that in these five cell lines, dengue-2 virus attached to each cell type equally well; however, this virus had higher replication rates and levels of virion production in differentiated Huh7, PLC, Hep3B, and Chang liver cells. Likewise, a lower replication rate was observed in the de-differentiated HA22T cells. Differentiation-related factors seem to play an important role in dengue virus replication. Further study showed that sodium butyrate (NaB, a differentiation inducer) treatment enhanced dengue virus replication in HA22T cells. Moreover, we found that the severity of morphologic aberration and the increase in aspartate aminotransferase (AST) levels correlated with the virus replication rate in the four infected hepatoma cells. In conclusion, we showed that dengue virus can infect diverse liver cells with differing replication efficiency, which causes cytopathic effects (CPEs) of diverse severity. Among the CPEs, the increased AST levels correlated with the clinical results from 24 dengue fever patients, who showed increased AST levels at the onset of fever. In summary, we find that dengue-2 virus replicates actively and causes severe CPEs in differentiated hepatoma cells. Factors related to differentiation as well as tumorigenicity seem to play critical roles, though the mechanisms of action remain unclear.
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PMID:Infection of five human liver cell lines by dengue-2 virus. 1068 26


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