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)

We determined the molar ratio of branched-chain amino acids to tyrosine (BTR) in plasma and in serum by enzymatic method and compared it with Fischer ratio (the molar ratio of branched-chain amino acids to tyrosine and phenylalanine) in plasma obtained by conventional HPLC method. BTR in plasma and in serum was well correlated with plasma Fischer ratio. The normal range (mean +/- 2SD) of BTR was determined to be 4.41-10.05 in 210 normal subjects. In addition, we investigated the distribution of BTR values in patients with various liver diseases. BTR value decreased according to the severity of liver disease. We evaluated the clinical usefulness of BTR in patients with chronic liver diseases by cumulative distribution analysis (CDA) graph and receiver operating characteristic curve (ROC) analysis. The area under the curve for BTR analyzed by ROC for CH versus LC.HCC group was the highest (86.3%) of any for various concurrently-measured liver function tests, and was significantly higher than AST/ALT, ALT, AST, gamma-GT (each, p less than 0.001) and ALB (p less than 0.05). These diagnostic results showed that BTR is a superior indicator in discriminating between liver cirrhosis and chronic hepatitis.
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PMID:[The clinical usefulness of the molar ratio of branched-chain amino acids to tyrosine (BTR) in discriminating stage of chronic liver diseases]. 151 41

Rat liver N-hydroxy-2-acetylaminofluorene (N-OH-2AAF) sulfotransferase activity is mediated by aryl sulfotransferase IV (AST IV) and causes the bioactivation of N-OH-2AAF to a highly reactive sulfuric acid ester form putatively capable of inducing liver cancer. Dietary administration of 2-acetylaminofluorene (2AAF) to induce hepatocarcinogenesis in rats has been shown to cause a rapid loss in N-OH-2AAF sulfotransferase activity. A possible mechanism for the in vivo loss in sulfotransferase activity may be the PAPS-dependent, sulfotransferase-catalyzed, reaction product inactivation of the enzyme by covalent reaction with the N-OH-2AAF sulfuric acid ester. In vitro studies to evaluate this possibility utilized a highly purified form of AST IV and measured the extent of PAPS-dependent interaction between the enzyme and N-OH-2[9-14C]AAF. The results showed the presence of a adenosine-3'-phospho-5'-phosphosulfate (PAPS)-dependent 14C-labeling of AST IV. The labeling could be blocked if the sulfotransferase inhibitor pentachlorophenol was present. Analysis of 14C-labeled AST IV following alkaline digestion and chromatography of digestion products indicated that AST IV cysteine and methionine residues were primary sites of 2[9-14C]AAF adduction. Studies involving the pretreatment of AST IV with PAPS and N-OH-2AAF prior to the measurement of N-OH-2AAF sulfotransferase activity showed a close parallel between formation of the AST IV cysteine-2AAF adduct and loss of activity. Similar studies showed that enzyme inactivation and cysteine-2AAF adduct formation could be blocked when excessive amounts of a competing nucleophile, methionine, were present during the pretreatment step, suggesting that inactivation does not proceed by a mechanism-based process. Finally, experiments involving prior reaction of AST IV with the thiol-blocking agent, N-ethylmaleimide, before measurement of enzyme activity showed essentially full loss of sulfotransferase activity and suggested that formation of AST IV cysteine-2AAF adducts could be a mechanism for enzyme inactivation. These results indicate that the in vitro inactivation of AST IV by the reactive N-OH-2AAF sulfuric acid ester is accompanied by covalent binding to AST IV, possibly through the formation of cysteine-2AAF adducts, and suggests that this mechanism merits further consideration as a basis for the loss of N-OH-2AAF sulfotransferase activity in vivo.
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PMID:Reaction product inactivation of aryl sulfotransferase IV following electrophilic substitution by the sulfuric acid ester of N-hydroxy-2-acetylaminofluorene. 173 62

The usefulness of the serum aspartate aminotransferase (AST): serum alanine aminotransferase (ALT) ratio as a guide to the presence of alcoholism was evaluated in four groups of patients. In alcoholics with elevated transaminases the mean AST:ALT ratio was found to be 1.50 (95% confidence interval (CI): 1.49-1.51), in hepatitis B infection 0.51 (95% CI: 0.50-0.52), in liver cancer 1.25 (95% CI: 1.20-1.29), and in nonmalignant obstructive jaundice 0.59 (95% CI: 0.57-0.61). In alcoholics with normal transaminases the AST:ALT ratio was 1.64 (95% CI: 1.61-1.67). The combination of an AST:ALT ratio of greater than 1.00 with an erythrocyte mean cell volume (MCV) above 90.0 fL resulted in a sensitivity of 97.3% and a specificity of 88.9% for detecting alcoholism in these four groups of patients.
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PMID:A combination of raised serum AST:ALT ratio and erythrocyte mean cell volume level detects excessive alcohol consumption. 238 15

Rat liver cytosolic sulfotransferase activity forms the highly reactive sulfuric acid ester of N-hydroxy-2-acetylaminofluorene (N-OH-2AAF), an ultimate carcinogen in 2-acetylaminofluorene (2AAF) hepatocarcinogenesis. A previous report demonstrated that 2AAF-induced liver hyperplastic nodules displayed a persistent loss of cytosolic N-OH-2AAF sulfotransferase activity following a hepatocarcinogenesis-producing regimen of 2AAF administration. As an initial step in examining the mechanism responsible for lowering N-OH-2AAF sulfotransferase activity, a monospecific polyclonal antibody to aryl sulfotransferase IV (AST IV) was produced and used in the assessment of AST IV as a candidate enzyme for liver cytosolic N-OH-2AAF sulfotransferase activity. Studies comparing the levels of N-OH-2AAF sulfotransferase activity of highly purified AST IV and rat liver cytosols with corresponding immunochemical analysis of AST IV contents demonstrated that there was sufficient AST IV activity in liver cytosols to indicate that it was the primary enzyme catalyzing cytosolic N-OH-2AAF sulfation. A subsequent immunochemical survey of nine extrahepatic tissues showed no detectable AST IV content and indicated that AST IV expression may be tissue specific. An immunochemical comparison of AST IV levels in control liver cytosols (high in sulfotransferase activity) with cytosols from 2AAF-derived hyperplastic nodules (low in sulfotransferase activity) or liver tumors (no sulfotransferase activity) showed low or no detectable levels, respectively, of AST IV. In addition, an immunochemical analysis of four rat hepatoma cell lines showed they contained no detectable levels of AST IV. These results suggested a strong correlation existed between a decrease in AST IV expression and tumor development. When the liver cytosols of rats taken from early, intermediate, and late stages of 2AAF carcinogenesis were analyzed for the development of a persistent loss of N-OH-2AAF sulfotransferase activity, a parallel loss of cytosolic N-OH-2AAF sulfotransferase activity and AST IV content was observed in rats which had proceeded from a stage of low risk to high risk for liver cancer. These findings indicated that (a) AST IV, a liver-specific enzyme, was the principle enzyme comprising cytosolic N-OH-2AAF sulfotransferase activity and (b) the decrease in sulfotransferase activity in nodules and tumors resulted from a decrease in the level of AST IV expression. Furthermore, it is suggested that a persistent decrease in AST IV expression may reflect a role for AST IV as part of a resistance phenotype in which transforming liver cells are able to escape the cytotoxic effects of highly reactive 2AAF metabolites and progress to cancer.
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PMID:2-Acetylaminofluorene-mediated alteration in the level of liver arylsulfotransferase IV during rat hepatocarcinogenesis. 238 38

The presence and distribution of AFP, AAT and HBsAg in peritumoral non-neoplastic hepatocytes (NNH) of 27 cases and, at the same time, in the neoplastic tissue of 37 liver cell carcinoma (HCC) were studied; AFP and HBsAg were more frequently found in NNH than in HCC cells; no differences were found for AAT. The presence of HBsAg also in normal liver without cirrhosis is probably best explained by its possible role in neoplastic transformation and by the inhibition of replication of the viruses AFP, considered to be expression of dedifferentiated cells, may possible be taken up by NNH for catabolic purposes.
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PMID:Immunohistochemical study of the appearance of some markers in liver adjoining hepatocellular carcinoma. 242 60

Increased AFP levels in patients with hepatocellular carcinoma are mainly related to tumor size and in a lesser degree, to AST levels. Abnormal and/or diagnostic AFP levels will be observed in a reduced proportion of patients with small HCC (less than 5 cm). Therefore, AFP measurement is of little value in the early detection of HCC.
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PMID:Alpha-fetoprotein in the early diagnosis of hepatocellular carcinoma. 248 Apr 20

Between December 1973 and September 1987, 21 patients with primary liver cancer and 41 patients with metastatic liver cancer were treated with external irradiation, intra-arterial infusion chemotherapy and/or transarterial embolization (TAE) at the National Medical Center Hospital, the National South Kyushu Central Hospital and the National Kure Hospital. Of the patients with primary liver cancer, 13 cases were treated with intra-arterial infusion chemotherapy (30-40 mg adriamycin or 10 mg mitomycin C) and hepatic irradiation. Eight cases were treated by TAE and hepatic irradiation. In the Child A group, the survival period of the chemotherapy + hepatic irradiation cases (mean: 608 days) was longer than that of the TAE + hepatic irradiation cases (mean: 216 days). The median survival period of all the cases was 7.0 months (mean: 10.9 months). For 16 of the 21 patients (who had absorbed over 40 Gy), the median survival period was 11.9 months (mean: 11.7 months). For 5 of the 21 patients (who had absorbed below 40 Gy), the median survival period was 4.3 months (mean: 7.9 months). Of the patients with metastatic liver cancer, the median survival period was 7.2 months (mean: 8.0 months). For 22 of the 41 patients (who had absorbed over 40 Gy), the median survival was 7.9 months (mean: 12.6 months). For 19 of the 41 patients (who had absorbed below 40 Gy), the median survival period was 1.7 months (mean: 2.6 months). The pretreatment serum GOT (glutamate oxaloacetate transaminase) levels and the pretreatment Karnofsky performance status index were the factors governing the prognosis of the cases with metastatic liver cancer, while toxicity was generally mild.
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PMID:Hepatic irradiation in primary and metastatic liver cancer. 292 86

3',5'-Dioctanoyl-5-fluoro-2'-deoxyuridine (FdUrd-C8), one of the lipophilic prodrugs of 5-fluoro-2'-deoxyuridine (FdUrd) was dissolved in an oily lymphographic agent (Lipiodol Ultra-Fluid), which had been studied as a carrier of the anticancer drug for hepatic cancer. The prodrug was administered into the left proper hepatic artery of rabbits bearing VX-2 tumor in the liver in order to examine the anticancer effects and possible adverse effects on nontumorous hepatic cells. Lipiodol or FdUrd-C8*Lipiodol selectively remained in the hepatic cancer area but disappeared from nontumorous parts of the liver 7 days after injection. Tumor growth rates in 1 week of the untreated group, a group given injections of 0.2 ml of Lipiodol alone, and groups given injections of 0.2 ml of Lipiodol containing 30, 50, 70, and 100 mg of FdUrd-C8 were 636, 436, 34.8, 14.9, -2.4, and -10.4% of the size at the time of treatment, respectively. Pathological observation also showed that FdUrd-C8 had a strong anticancer effect on VX-2 tumor growing in the liver of the rabbits. In contrast to the effect on the cancerous cells, that on nontumorous hepatic cells was very slight. In pathological observation, necrosis or degeneration of nontumorous hepatic cells was hardly observed. Plasma glutamic-oxaloacetic transaminase and glutamic-pyruvic transaminase levels temporarily rose 1 day after injection but returned to the initial levels within 7 days in all groups.
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PMID:Selective anticancer effects of 3',5'-dioctanoyl-5-fluoro-2'-deoxyuridine, a lipophilic prodrug of 5-fluoro-2'-deoxyuridine, dissolved in an oily lymphographic agent on hepatic cancer of rabbits bearing VX-2 tumor. 302 18

Hepatocarcinogenesis is deterministic in transgenic mice expressing in the liver gene construct Alb-DS4 that encodes autocrine growth factor IgEGF (D Stern et al. (1987), Science 235: 321-324), causing their death within 7.1 months. Hepatic expression of construct AAT-myc encoding murine c-myc causes liver cancer in 44% of the mice at 14.8 months. Cooperation of these genes was evident in CD2F1 transgenics bearing Alb-DS4 plus AAT-myc, in which accelerated hepatocellular carcinoma (HCC) formation caused death of all mice within 4.4 months. Alb-DS4 also cooperates with the Hcs locus, which in C3H/HeJ mice mediates high susceptibility to spontaneous hepatocarcinogenesis, causing accelerated formation of HCC to which mice succumbed at 5.1 months. Thus, genes that predispose to HCC formation cooperate in transgenic mice and their interaction is a key to understand mechanisms that cause liver cancer.
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PMID:Autocrine mitogen IgEGF cooperates with c-myc or with the Hcs locus during hepatocarcinogenesis in transgenic mice. 786 54

Plachitin formed of both poly-N-acetyl-D-glucosamine (chitin) and cis-diamminedichloroplatinum (CDDP), was used as an arterial chemoembolization therapy against unresectable liver cancer. One gram of Plachitin contained 300 mg of CDDP. The Plachitin particle was 50-100 microns in diameter. Plachitin particles (50-100 mg) were injected via hepatic artery once or twice every week, and the total amount of 300 mg was considered one course of this therapy. The size and number of tumors were measured by computer tomography (CT). Pharmacokinetics of this drug was also assessed by serum and urine platinum (Pt) concentration. Three patients underwent the chemoembolization therapy using plachitin particles. Case 1 had multiple hepatocellular carcinomas. The tumor regression rate was 39% after two courses of this therapy. Serum alpha-fetoprotein (AFP) level decreased from 1,182 ng/ml to 300 ng/ml. Case 2 suffered from bile duct cystadenocarcinoma. After three courses of the therapy, the tumor regression rate was 84.4%. Serum carbohydrate antigen 19-9 (CA19-9) decreased from 731 U/ml to 75 U/ml. Case 3 had synchronous multiple liver metastases from sigmoid colon cancer. The tumor regression rate was 77% after one course of the therapy. Carcinoembryonic antigen (CEA) and CA19-9 decreased from 406 ng/ml to 65 ng/ml and from 4,800 U/ml to 790 ng/ml, respectively. The response rate of the 3 cases was 66.7%. The peak levels of the serum Pt concentration of three patients were 0-0.4 microgram/g throughout the therapy, but peak urine Pt concentrations were observed during one course of the therapy of three patients ranging from 0.5 microgram/g to 3.2 micrograms/g, and decreased gradually for three weeks after the first course. Adverse effects of Plachitin particles for arterial chemoembolization were epigastralgia, nausea, fever, and elevation of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels. These adverse effects were observed in all patients, but were transient. Catheter obstruction occurred in one patient (case 2). Cholecystitis, pancreatic pseudocyst, and duodenal ulcer were noticed in case 3. No renal hypofunction was observed. Plachitin might be a useful agent for arterial chemoembolization therapy for primary and secondary liver cancer.
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PMID:[Intraarterial chemoembolization therapy for unresectable liver cancer using plachitin particles]. 794 46


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