Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0019163 (hepatitis B)
 38,309 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The etiologic relationship of parasitic liver disease to primary liver cancer has long been debated. For this reason, a review of 4611 necropsies was carried out to determine the frequency with which hepatocellular carcinoma occurred in association with schistosomiasis. Of 227 cases of hepatocellular carcinoma, 24 (10.6%) were associated with schistosomiasis japonica. This was significantly higher than the incidence of this carcinoma without schistosomiasis (2.78%). The majority of the 24 cases exhibited the features of a mixed macronodular and micronodular cirrhosis (Gall's posthepatitic cirrhosis); this was super-imposed upon and caused a masking of schistosomiasis fibrosis. By radioimmunoassay hepatitis B antigen was positive in 27% of these cases. A review of the literature indicated that chronic schistosomiasis, on its own, is unlikely to be the cause of primary liver cell carcinoma. Histologic features resembling post-hepatitic cirrhosis combined with a high frequency of hepatitis B antigen suggest that viral hepatitis rather than S. japonicum is the more likely etiologic factor involved, or has a synergistic effect on carcinogenesis.
 ...
PMID:Primary liver cancer coincident with Schistosomiasis japonica. A study of 24 necropsies. 16 89

Liver-cell dysplasia is a well known histological entity with preneoplastic significance in experimental hepatic carcinogenesis. However, while the association of liver-cell dysplasia with hepatitis B virus can be considered as established, it is still controversial whether this lesion represents a premalignant condition in cirrhotic patients. Efforts have been made to render its morphological assessment more reliable, but no firm conclusions can be drawn from the available clinical studies, which are mainly retrospective or based on autopsy series. Preliminary results from a prospective study argue that liver-cell dysplasia is associated with an increased risk to hepatocellular carcinoma. The emergence of liver-cell dysplasia as a preneoplastic lesion in cirrhotic patients will have some impact in the future on their management, including selection for closer monitoring in early detection of hepatocellular carcinoma and for liver transplantation.
 ...
PMID:Liver-cell dysplasia and hepatocellular carcinoma. 131 75

Immunohistochemical evaluation of Cu, Zn- and Mn-superoxide dismutase (SOD) activity in various viral liver diseases was performed by the peroxidase-conjugated antibody indirect method. Anti-human Cu, Zn-SOD (rabbit) and anti-human Mn-SOD (guinea-pig) derived and purified from SOD of human erythrocytes and placentas were used to determine SOD distribution in liver tissues. SOD in the liver tissues was detected in 68 inpatients of our unit. They consisted of 23 cases with chronic hepatitis caused by hepatitis B virus (13) and hepatitis C virus (10), 24 with liver cirrhosis caused by hepatitis B virus (5) and hepatitis C virus (19) (15: compensatory, 9: decompensatory) and 21 with hepatocellular carcinoma caused by hepatitis B virus (2) and hepatitis C virus (18) complicated of liver cirrhosis. In viral liver diseases, SODs in the liver tissues were distributed to hepatocytes mainly in the pattern of cytoplasmic diffusion. The incidence of immunohistochemical Cu, Zn-SOD and Mn-SOD were 47.8% and 56.5% in chronic hepatitis, 93.3% and 86.7% in compensated liver cirrhosis, 11.1% and 22.2% in decompensated liver cirrhosis, respectively. The aggression of viral liver disease was accompanied with the decrease of SOD concentration in the liver tissues. Hepatocellular carcinoma cells were negative for Mn-SOD in all cases, and weakly positive for Cu, Zn-SOD in 2 out of 21 cases. Comparatively strongly positive SOD findings were obtained from normal regions neighboring carcinomas. A close relationship between the depletion of SOD in liver tissues and carcinogenesis in viral liver diseases was observed.
 ...
PMID:Relationship between superoxide dismutase (SOD) and viral liver diseases. 132 May 79

Although epidemiologic studies have clearly demonstrated the importance of the hepatitis B virus in the genesis of hepatocellular carcinoma, the molecular basis for this tumorigenic effect is still under debate. The finding of hepatitis B virus DNA integration into human liver DNA in many cases of hepatocellular carcinoma suggested that these integrated viral sequences may be involved in liver carcinogenesis. In an attempt to clarify this point, we studied 9 tumors which developed in non cirrhotic livers. All tumors contained viral integrations (ranging from 1 to 6 different integrants) and 4 showed abnormal hepatitis B virus mRNA (2.3 to 7.5 kilobases long). The analysis of the corresponding cDNAs revealed the existence of hybrid transcripts containing both genomic and viral sequences. In 2 cases, the viral-host junctions were mapped within the cohesive-end region of the hepatitis B virus genome leading to the production of a transcript encoding a 3' truncated X protein. In another case, the cellular sequences present in the co-transcript were located in 5' with respect to the hepatitis B virus sequences. This observation strongly suggests that, in this patient, integration took place near a cellular gene. Further analysis of this integrant should help in identifying the putative gene and its application in the development of the tumor. We conclude that the study of abnormal hepatitis B virus transcripts in liver tumors provides a positive approach to study the direct role of HBV in carcinogenesis as an insertional mutagen.
 ...
PMID:[Abnormal expression of hepatitis B virus sequences integrated in human hepatocellular carcinomas]. 132 60

Chronic infection by hepatitis B and C viruses is frequently associated to the development of primary liver cancer. Liver cirrhosis, induced by these viral infection, plays an important role in the liver carcinogenesis. In addition, HBV has a direct role in liver cell transformation by a transactivating effect of some viral proteins as well as insertional mutagenesis. The role of hepatitis C virus is not known. The strong association, even in France, of primary liver cancer to these viral infections underline the importance of their prevention by vaccination.
 ...
PMID:[Liver cancer and hepatitis B and C virus]. 133 32

To study the oncogenesis of human esophageal carcinoma, the presence of DNA sequences homologous to several DNA tumor viruses and the expression of oncogenes and growth factor genes were examined in two esophageal carcinoma cell lines of Chinese origin, CE48T/VGH and CE81T/VGH. Southern blot analyses failed to detect sequences homologous to hepatitis B virus (HBV), Epstein-Barr virus (EBV), herpes simplex virus type 2 (HSV-2), cytomegalovirus (CMV) or human papilloma virus (HPV) genomes. Northern blot analyses revealed that c-myc, c-src, c-H-ras, c-abl, c-sis, and p53 genes were expressed. In addition, transcripts of transforming growth factor alpha (TGF alpha), TGF beta, and platelet derived growth factor A (PDGF A) genes were detected. These studies suggest that DNA tumor viruses may not be involved in the carcinogenesis of esophageal carcinoma. However, cooperation among different oncogenes and the production of growth factors may play an important role in that carcinogenesis.
 ...
PMID:Absence of genomes of DNA tumor viruses and expression of oncogenes and growth factors in two esophageal carcinoma cell lines of Chinese origin. 147 73

Persistent infection with hepatitis B virus (HBV) is a major cause of hepatocellular carcinoma (HCC) in humans. HCC has also been observed in animals chronically infected with two other hepadnaviruses: ground squirrel hepatitis virus (GSHV) and woodchuck hepatitis virus (WHV). A distinctive feature of WHV is the early onset of woodchuck tumors, which may be correlated with a direct role of the virus as an insertional mutagen of myc genes: c-myc, N-myc, and predominantly the woodchuck N-myc2 retroposon. In the present study, we searched for integrated GSHV DNA and genetic alterations of myc genes in ground squirrel HCCs. Viral integration into host DNA was detected in only 3/14 squirrel tumors and did not result in insertional activation of myc genes, despite the presence of a squirrel locus homologous to the woodchuck N-myc2 gene. This suggests that GSHV may differ from WHV in its reduced ability to induce mutagenic integration events. However, the high frequency of c-myc amplification (6/14) observed in ground squirrel HCCs indicates that myc genes might be preferential effectors in the tumorigenic processes associated with rodent hepadnaviruses, a feature not reported so far in HBV-induced carcinogenesis. Together with previous observations, our results suggest that hepadnaviruses, despite close genetic and biological properties, may use different pathways in the genesis of liver cancer.
 ...
PMID:Frequent amplification of c-myc in ground squirrel liver tumors associated with past or ongoing infection with a hepadnavirus. 157 Mar 7

Hepatocellular carcinomas in woodchuck were characterized for woodchuck hepatitis virus integration near c-myc oncogene. In one tumor, viral integration resulted in overexpression of a c-myc viral cotranscript. In a second tumor, viral insertion, 600 bp upstream of c-myc exon 1, was associated with increased levels of normal c-myc mRNA. These results demonstrate that integration of woodchuck hepatitis virus near a proto-oncogene can contribute to the genesis of liver tumors. From a comparison of a single hepatitis B virus (HBV) integration site in a human hepatoma with the corresponding unoccupied site have shown HBV DNA insertion in a putative cellular exon. This exon presented striking similarity to the DNA-binding domain of the thyroid/steroid hormones receptors. The corresponding cDNA has been isolated (hap gene) a shown to encode the retinoic acid receptor. It is most probable that consequent to HBV insertion, has became inappropriately expressed as an altered chimaeric gene retinoic acid receptor, thus contributing to the cell transformation. As for woodchuck these results strongly support the possibility that HBV may play a direct role in liver carcinogenesis by insertional mutagenesis.
 ...
PMID:[Hepatitis B virus and hepatocellular carcinoma]. 165 Jun 25

The multistep aspects of carcinogenesis including initiation and promotion problems in both human and experimental hepatocarcinogenesis are discussed, especially in terms of oncogene and antioncogene changes. It is shown that the H-ras activation may be an event occurring in relatively late phase of carcinogenesis in the mouse systems, and that hepatitis B integration frequently causes host chromosomal rearrangement possibly leading to inactivation of cancer suppressor genes. In addition, significance of endogenously-produced nitrosamines in hepatocarcinogenesis is pointed out.
 ...
PMID:[Pathogenesis of human cancer]. 165 95

Cytogenetic analysis of metaphase chromosome spreads from peripheral blood cells of hepatitis B virus (HBV) chronic carriers and HBV-negative individuals of the same ethnic origin revealed a significantly higher incidence of chromosome breaks and other mitotic aberrations in the HBV chronic carriers. The highest incidence of chromosome breaks was found in chronic carriers who evidenced circulating HBV. Such an association between HBV and these genetic lesions assumes importance in light of the known correlation between HBV chronic carrier status and the high risk of hepatocellular carcinogenesis, where a mutagenic effect of HBV cannot be excluded.
 ...
PMID:Chromosome abnormalities in peripheral blood cells of hepatitis B virus chronic carriers. 165 81


1 2 3 4 5 6 7 8 9 10 Next >>