Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019204 (hepatocellular carcinoma)
 71,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Infection with hepadnaviruses and exposure to dietary aflatoxin are considered major risk factors in the development of hepatocellular carcinoma (HCC) both in humans and in animals. Recently, a broad range of mutations in the p53 tumor suppressor gene has been reported in human HCCs, predominantly from hepatitis B virus carriers in areas with either high or low levels of exposure to dietary aflatoxin. To determine whether p53 mutations are common to HCCs of hosts infected with related hepadnaviruses with and without treatment with aflatoxin, we studied the occurrence of mutations in the p53 gene in HCCs of ground squirrels and woodchucks with history of infection with ground squirrel hepatitis virus (GSHV) and woodchuck hepatitis virus, respectively. Sequencing of wild type p53 genes from ground squirrels and woodchucks revealed remarkable homology between the two species with only a few amino acid differences in exons 4, 8, and 9. Using direct polymerase chain reaction sequencing, we analyzed the state of the p53 gene (exons 4-9) in 20 HCCs from ground squirrels (2 uninfected, 7 with past, and 11 with ongoing infection with GSHV) and in 11 HCCs from woodchucks persistently infected with woodchuck hepatitis virus. Five GSHV carrier and two uninfected ground squirrels received i.p. administration of aflatoxin B1. We detected only one mutation in the p53 gene of the tested animals. This mutation was located in codon 176 of exon 5 in the HCC of a GSHV-positive ground squirrel treated with aflatoxin. Mutation was caused by a G to T transversion in the second position of the codon, resulting in the replacement of cysteine with phenylalanine, and was accompanied by a tumor-specific loss of heterozygosity. p53 allelic amino acid variation with sequences coding for aspartic acid or asparagine was present in codon 61 in the variable region of exon 4 in both HCCs and nonneoplastic tissues of ground squirrels. In view of the considerably lower apparent rate of mutations in comparison to human HCCs, we suggest a less important role for aflatoxin in the induction of p53 mutations in HCCs of ground squirrels. Alternatively, etiological factors other than p53 mutations may be of greater significance in the development of HCC in ground squirrels and woodchucks.
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PMID:State of the p53 gene in hepatocellular carcinomas of ground squirrels and woodchucks with past and ongoing infection with hepadnaviruses. 792 76

To evaluate whether neutrophil bactericidal function, the ability to produce oxygen-derived free radicals, is altered in patients with chronic liver disease, we measured chemiluminescence amplified by a luciferin analog (Cypridina luciferin analog-dependent chemiluminescence) and luminol (luminol-dependent chemiluminescence) in response to N-formyl-Met-Lue-Phe by neutrophils from patients with chronic liver diseases due to C and/or B type hepatitis: chronic active hepatitis, cirrhosis and hepatocellular carcinoma. Both Cypridina luciferin analog-dependent chemiluminescence and luminol-dependent chemiluminescence were significantly decreased in neutrophils from patients with chronic liver disease (hepatocellular carcinoma < cirrhosis < chronic active hepatitis) when they were compared with normal healthy subjects. The reduction of Cypridina luciferin analog-dependent chemiluminescence in chronic active hepatitis and cirrhosis was more sensitive than Cypridina luciferin analog-dependent chemiluminescence; however, in hepatocellular carcinoma, luminol-dependent chemiluminescence was more reduced than luminol-dependent chemiluminescence. Although there were not significant correlations between glutamic pyruvic transaminase and Cypridina luciferin analog-dependent chemiluminescence/luminol-dependent chemiluminescence, there were significant negative correlations between total bilirubin and Cypridina luciferin analog-dependent chemiluminescence/luminol-dependent chemiluminescence. Furthermore, there were significant positive correlations between albumin/prothrombin time and Cypridina luciferin analog-dependent chemiluminescence/luminol-dependent chemiluminescence. These data suggest that an impaired ability to produce oxygen-derived free radicals may contribute to the susceptibility to infection in patients with chronic liver disease.
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PMID:Impaired ability of neutrophils to produce oxygen-derived free radicals in patients with chronic liver disease and hepatocellular carcinoma. 804 92

This paper is a study to identify the clinical significance of high-molecular-mass alkaline phosphatase (ALP:E:C..3.1.3.1.), ALP-lipoprotein-X complex (LP-X) and intestinal variant ALP. We used cellulose acetate and agarose gels and techniques including wheat germ lectin, cetavlon-diethyl ether, thermostatability, neuraminidase and L-phenylalanine to improve the electrophoretic separation of the alkaline phosphatase isoenzymes. Patients' serum samples were electrophoresed from a diverse group of individuals ill with cholestasis, neoplastic disease metastatic to the liver, hepatocellular carcinoma, cirrhosis, diabetes mellitus, and chronic renal disease. Agarose gels provided better separation of ALP isoenzymes than cellulose acetate gels. The results also indicated that high-molecular mass ALP is present in patient's serum in conditions associated with cholestasis especially caused by hepatic malignancy. High-molecular mass ALP was frequently found to co-exist with the liver isoenzyme and LP-XALP complex. The intestinal variant was identified in patients with malignancy, cirrhosis, chronic renal disease and diabetes mellitus. Intestinal ALP coexisted concomitantly with a variant intestinal ALP. Intestinal variant ALP is most likely composed of intestinal ALP attached to a cellular membrane-binding domain, or may be an artifact produced by neuraminidase incubation.
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PMID:Clinical significance of serum high-molecular-mass alkaline phosphatase, alkaline phosphatase-lipoprotein-X complex, and intestinal variant alkaline phosphatase. 804 46

We showed previously that the abundance of serum albumin mRNA is decreased in H4-II-E rat hepatoma cells limited for a single essential amino acid (phenylalanine, methionine, leucine, or tryptophan). To define the specificity of this phenomenon, we examined the effect of amino acid limitation on the abundance of mRNAs for 19 genes in the H4-II-E cells. These genes included six genes whose expression is either completely liver-specific or highly enriched in the liver compared with other tissues [albumin, transthyretin (TTR), transferrin, carbamyl phosphate synthetase-I, urate oxidase, class I alcohol dehydrogenase], as well as a number of ubiquitously expressed "housekeeping" genes. The results indicated that the 19 genes could be divided into three classes based on their response to amino acid limitation. Class I genes (the six liver-specific genes and alpha-tubulin) exhibit decreased expression in response to amino acid limitation. The expression of class II genes [beta 2-microglobulin, hypoxanthine-guanine phosphoribosyl transferase (HPRT), H-ferritin, ubiquitin (UbB), insulin-like growth factor binding protein-4, HNF-1 alpha] is not significantly affected by amino acid limitation. Class III genes [gadd153, beta-actin, ubiquitin (UbC), phosphoglycerate kinase-1, C/EBP alpha, C/EBP beta] exhibit increased expression in response to amino acid limitation. Thus, specific inductive as well as repressive effects on gene expression are quite common in amino acid-limited cells. The observation that all six genes whose expression is liver-specific exhibited decreased expression in amino acid-limited cells suggests a common mode of regulation of these genes by amino acid availability. The strong induction by amino acid limitation of the C/EBP inhibitor gadd153 is of interest in this regard, as increased levels of gadd153 could interfere with C/EBP, which is required for high expression of most liver-specific genes. To investigate further the molecular mechanism for the decrease in albumin mRNA abundance, albumin nuclear transcript levels were quantified in control and tryptophan-limited cells. Tryptophan limitation caused a decrease in albumin nuclear transcript abundance, and this decrease preceded the decrease in albumin mRNA, suggesting that the decrease in albumin mRNA was caused at least partly by a decrease in albumin gene transcription. Additional experiments with actinomycin D indicated that albumin mRNA was also destabilized in the tryptophan-limited cells. Thus, the overall results indicate that the decrease in albumin mRNA in the tryptophan-limited cells is caused by a specific decrease in albumin nuclear transcript abundance and destabilization of albumin mRNA.
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PMID:Effect of amino acid limitation on the expression of 19 genes in rat hepatoma cells. 818 73

A G:C-->T:A mutational hotspot at codon 249 of the p53 tumor suppressor gene has previously been identified in hepatocellular carcinoma (HCC) of patients from Qidong, China and southern Africa in which aflatoxin B1 (AFB1) and hepatitis B virus (HBV) are known synergistic risk factors. We have examined p53 mutation patterns of HCC from geographic areas in which the risk factors vary. Nine HCC lines and four hepatoblastoma lines (HB) were examined for p53 gene mutations and the relationship with HBV infection. Five of the nine HCC lines had homozygous mutation or deletion randomly distributed in exons 6-8, whereas none of the four HB cell lines had p53 mutations. One of the four HB lines (HepG2) had an N-ras mutation at codon 61 position 2. The p53 point mutations in the three HCC cell lines from Japan resulted in the amino acid changes of cysteine for tyrosine in cell line HuH 7 at codon 220 (A:T-->G:C), alanine for glycine in cell line HLF at codon 244 (G:C-->C:G), and serine for arginine in cell line HLE at codon 249 (G:C-->C:G). In addition, the deletion of 18 base pairs from codon 264 position 3 to codon 270 position 1 has resulted in the deletion of Leu-Gly-Arg-Asn-Ser-Phe from the amino acids sequences 256-270 in the Japanese cell line HuH 4. The cell line PLC/PRF/5 that showed p53 mutation at codon 249 (G:C-->T:A) with substitution of serine for arginine was derived from a South African patient. Our results indicate that whereas the p53 gene is not mutated in the HB cell lines, the HCC cell lines frequently contain an abnormal p53 gene. In addition, p53 point mutations were not detected in the four Japanese HCC cell lines that were positive for genomic integration of HBV X-gene and surface antigen gene. The three Japanese HCC cell lines with p53 mutations did not contain HBV sequences, indicating that hepatocarcinogenesis associated with p53 mutation does not require the genomic integration of HBV sequences.
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PMID:p53 gene mutation and integrated hepatitis B viral DNA sequences in human liver cancer cell lines. 838 56

The effect has been studied of various media, hormones and of amino acids on the membrane potential of rat hepatoma cells in culture measured by microelectrode impalement. Cells in Eagle's minimal essential medium plus 5% serum had a value which varied daily from about 5-8 mV, inside negative. The membrane potential of rat hepatocytes was measured to be 8.7 +/- 0.2 mV, inside negative. The membrane potential of the hepatoma cells was decreased by insulin and increased by glucagon. Membrane potential was unaffected by change of medium to Hanks' or Earle's balanced salt solutions or deprivation of serum. It was, however, reduced in cells in phosphate-buffered saline and by reduction of pH. The former effect was shown to be due to the higher [Na+] of phosphate-buffered saline as opposed to the other media. Addition of alanine, glycine, serine, proline and methylaminoisobutyrate all reduced membrane potential by 2-3 mV. Smaller decreases were seen with methionine, leucine and phenylalanine, but none with glutamine, threonine, BCH (2-aminonorborane-2-carboxylic acid) and D-alanine. The results are compared with the effects of similar conditions on aminoisobutyrate uptake. Whilst there was a correlation under some conditions there was not under others. It is concluded that for the hepatoma cells factors additional to the membrane potential must exert some influence on the capacity for amino acid transport.
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PMID:Membrane potential of rat hepatoma cells in culture: influence of factors affecting amino acid transport. 856 68

We have developed a useful strategy for identifying amino acid spin systems and side-chain carbon resonance assignments in small 15N-, 13C-enriched proteins. Multidimensional constant-time pulsed field gradient (PFG) HCC(CO)NH-TOCSY experiments provide side-chain resonance frequency information and establish connectivities between sequential amino acid spin systems. In PFG HCC(CO)NH-TOCSY experiments recorded with a properly tuned constant-time period for frequency labeling of aliphatic 13C resonances, phases of cross peaks provide information that is useful for identifying spin system types. When combined with 13C chemical shift information, these patterns allow identification of the following spin system types: Gly, Ala, Thr, Val, Leu, Ile, Lys, Arg, Pro, long-type (i.e., Gln, Glu and Met), Ser, and AMX-type (i.e., Asp, Asn, Cys, His, Phe, Trp and Tyr).
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PMID:Classification of amino acid spin systems using PFG HCC(CO)NH-TOCSY with constant-time aliphatic 13C frequency labeling. 858 9

The effect of tumor resection on protein metabolism in cancer-bearing subjects is poorly documented. We explored changes in nitrogen (N) and protein metabolism after excision of tumors both at the whole body level (N balance) and at the tissue level, including skeletal muscle, small intestine, and liver. Sixteen male Sprague-Dawley rats (approximately 375 g) bearing subcutaneous Morris hepatoma 7777 for 6 weeks were either operated for tumor excision and studied for 10 days postoperatively (n = 10) or sacrificed on the day of surgery as tumor-bearing controls; operated and unoperated tumor-bearing rats were compared with healthy rats (n = 16). Tumors, which grew to a mass of 74 +/- 7 g (mean +/- SEM), induced significant loss of body mass (-27 +/- 13 g) and protein depletion in epitrochlearis muscle (EPI) (-38%) and small intestine (-42%) vs healthy rats. Tumor significantly decreased muscle protein synthesis vs healthy rats (7.14 +/- 0.5 vs 10.7 +/- 0.5 nmol phenylalanine (Phe)/EPI/3 hr), net degradation (21.7 +/- 2.9 vs 30.6 +/- 2.5 nmol Phe/EPI/3 hr) and degradation (28.8 +/- 2.7 vs 41.4 +/- 2.5 nmol Phe/EPI/3 hr). In 50% of operated rats, tumor removal was followed immediately by increased food intake, body weight, and N balance; in other rats, this was delayed by 2-4 days. By 6 days postoperative, all rats were gaining weight and had normal food intake; wasting was abolished in small intestine, but not in skeletal muscle (protein mass -43% vs healthy rats, P < 0.05). Postoperative rats maintained lower muscle protein degradation (28.2 +/- 2.0 vs 41.4 +/- 2.5 nmol Phe/EPI/3 hr, P < 0.05) than healthy rats; protein synthesis was no longer reduced. In skeletal muscle, protein synthesis and protein deposition were related to levels of postoperative food intake (r = 0.91 and 0.98, respectively; P < 0.05). Following tumor excision, reversal of cancer cachexia appeared to be highly dependent on the level of postoperative food intake.
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PMID:Protein metabolism in cachectic tumor-bearing rats: effect of tumor excision. 859 16

Hereditary tyrosinemia type I (HTI) (MIM 276700) is an autosomal recessive disorder caused by deficiency of fumarylacetoacetase (EC 3.7.1.2), which is the last enzyme in the tyrosine degradation pathway. The enzyme block causes accumulation of toxic metabolites in the liver and kidneys, which are the organs where tyrosine is mainly degraded. The disorder is characterized by severe liver disease, which either causes liver failure in infancy or may take a more protracted course, with death often occurring during childhood or adolescence because of hepatoma development. Treatment with a diet restricted in phenylalanine nd tyrosine does not prevent progression of the liver disease and development of hepatocellular carcinoma. Liver transplantation was previously the only option for these patients. Important achievements from metabolic and molecular biology studies of the disease include a new treatment for patients with HTI using an enzyme inhibitor, detection of self-induced correction of the genetic defect in regenerative liver nodules in HTI patients, identification and development of useful animal models for HTI, and studies of the molecular genetics of HTI. These advances will have great implications for our understanding of pathogenetic mechanisms, which is the basis for improved diagnostic methods and improved treatment of patients with HTI.
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PMID:Diagnosis and management of tyrosinemia type I. 877 26

Aberrations of the p53 and Rb tumour suppressor genes were examined in 12 human hepatocellular carcinoma (HCC)-derived cell lines from different geographic areas and 9 local HCCs by restriction fragment length polymorphisms (RFLP), polymerase chain reaction-single-strand conformation polymorphisms (PCR-SSCP) and DNA sequencing. The relationships between genetic changes and hepatitis B virus (HBV) DNA integration in samples were compared. None of the cell lines and tumours showed structural changes in the Rb gene, while 6 cell lines and 2 tumours had mutation or deletion in exons 5 to 8 of p53. Mutations include an AGG --> AGT (Arg --> Ser) transversion at codon 249 in PLC/PRF/5 and Mahlavu, an AAT --> AAA (Asn --> Cys) transversion at codon 200 in TONG/HCC, an AAG --> GAG (Lys --> Glu) transition at codon 139 in HCC-T, a CAT --> CGT (His --> Arg) transition at codon 214 in SC4, and a CCC --> CTC (Pro --> Leu) transition at codon 250 in SC8. In Huh4, an 18-bp deletion from codon 264 to 270 resulted in loss of Leu-Gly-Arg-Asn-Ser-Phe from the amino acid sequences 265 to 270, whereas Hep3B had a 7-kb deletion after exon 7 of p53. Our data indicate that whereas Rb may not have pleiotropic effects on HCC, p53 aberrations are frequently involved in hepatocarcinogenesis. Further, HBV infection appears to be unrelated to the micro-genetic changes of p53. The G to T codon-249-mutation is consistent with HCCs arising from areas at high risk for both aflatoxin B1 (AFB1) exposure and HBV infection.
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PMID:Tumour suppressor p53 and Rb genes in human hepatocellular carcinoma. 877 41


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