Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0019158 (hepatitis)
 30,205 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sera of 40 patients with posttransfusion non-A, non-B hepatitis were tested for hepatitis C and B viral genomes by polymerase chain reaction and for hepatitis C antibodies by synthetic peptide immunoassays. Five were then considered to have chronic hepatitis before transfusion. Six patients without hepatitis C markers and hepatitis B virus DNA recovered. In 29 recipients who became positive for hepatitis C virus RNA, posttransfusion hepatitis C was diagnosed. Of them, 5 were hepatitis B surface antigen carriers. Synthetic peptide immunoassays detected 28 whereas anti-C100 assay detected 23 of the 29 acute hepatitis C patients. Anticapsid antibody appeared earlier than the antinonstructural antibody in 10 seroconverters. They appeared simultaneously in 15 seroconverters but anticapsid antibody appeared later then the antinonstructural antibody in 3 hepatitis B carriers. Transient suppression of hepatitis B surface antigenemia was found in 2, whereas elevated hepatitis B virus DNA was found in 3 carriers during acute hepatitis C superinfection. In 2 carriers whose hepatitis C became chronic, both hepatitis B and C viral genomes persisted throughout 2 years of followup. Therefore these assays define posttransfusion hepatitis C more precisely, and there seems no significant interference between chronic hepatitis B and C virus infections.
 ...
PMID:Posttransfusion hepatitis revisited by hepatitis C antibody assays and polymerase chain reaction. 132 74

In persistent hepadnavirus infections, a distinctive feature of woodchuck hepatitis virus (WHV) is the coupling of frequent viral integrations into myc family genes with the rapid onset of primary liver tumors. We have investigated the patterns of WHV DNA insertion into N-myc2, a newly identified retroposed oncogene, in woodchuck hepatomas resulting from either natural or experimental infections. In both cases, integrated viral sequences were preferentially associated with the N-myc2 locus. In more than 40% of the woodchuck tumors analyzed, viral insertion sites were clustered in a 3-kb region upstream of N-myc2 or in the 3' noncoding region. Insertion of WHV sequences homologous to the human hepatitis B virus enhancers, either upstream or downstream of the N-myc2 coding domain, was associated with the production of normal N-myc2 mRNA or hybrid N-myc2-WHV transcripts, initiated at the normal N-myc2 transcriptional start site. Transient-transfection assays with different N-myc2-WHV constructs in HepG2 cells demonstrated that the viral enhancers could efficiently activate the N-myc2 promoter. These results, showing that cis activation of preferred cellular targets through enhancer insertion is a common strategy for tumor induction by WHV, emphasize the previously noted similarities between hepadnaviruses and nonacute oncogenic retroviruses.
 ...
PMID:Hepadnavirus integration: mechanisms of activation of the N-myc2 retrotransposon in woodchuck liver tumors. 132 93

Human hepatitis B virus (HBV) carriers run an increased risk of hepatocellular carcinoma (HCC), where the expression of HBV genes play the most important role in the initial stage of hepatocarcinogenesis. As the integration of HBV DNA into the cellular DNA of HCC as well as chronic hepatitis was demonstrated very frequently, the virus-cell fusion gene was considered to be most essential for hepatocarcinogenesis. Among the virus-cell fusion genes, the X gene is known to function as a transactivator for viral and cellular genes at the time of chronic infection. One mechanism for hepatocarcinogenesis that appears particularly reasonable is transactivation of cellular oncogenes by the X-cell fusion protein. In 1990, we found a part of the amino acid sequences in the X protein to be highly homologous to functionally essential sequences in the Kunitz domain, characteristic of Kunitz-type serine protease inhibitors. It has been recently demonstrated that X protein expressed in E. coli or from the in vitro translation system binds to a specific serine protease from the liver cells. These results indicate that transactivation function of X protein may be exerted by acting as a protease inhibitor analogue to control the proteolytic pathway of cellular transcription factor(s). On the other hand, viral hepatitis resulting from viruses other than hepatitis A virus and HBV has been referred to as non-A, non-B hepatitis. In 1989, the viral genome was molecularly cloned as a positive-strand RNA having about 10 kb in size and named as hepatitis C virus (HCV). Details of genetic structure and mechanism of expression are currently under investigation at molecular level.
 ...
PMID:[Gene expression of hepatitis viruses in the liver and hepatocarcinogenesis]. 132 91

Interferon-alpha (IFN-alpha) is known to inhibit both DNA and RNA viruses, including hepatitis B virus (HBV). In humans the antiviral effect, if any, of IFN-alpha on hepatitis delta virus (HDV) is complicated by the fact that HDV is spread only to patients already infected with HBV. An in vitro model system was used to assay for an antiviral effect of IFN-alpha on HDV genome replication. Hep G2 cells were transfected with a plasmid containing a trimer of HDV and treated with IFN (20 or 100 units/mL) starting 1-7 days after transfection. RNA extracted from treated and nontreated cells was assayed by both slot blot and Northern analyses. The IFN-alpha treatment as expected increased the 2'-5' oligo A synthetase RNA activity, but it did not affect HDV genome replication. Thus, in the absence of HBV, it appears that HDV is resistant to IFN-alpha.
 ...
PMID:Resistance of hepatitis delta virus replication to interferon-alpha treatment in transfected human cells. 132 4

Complementary DNA clones corresponding to one of the putative structural regions of the hepatitis C virus (HCV) genome were obtained from sera of non-A non-B hepatitis patients. The putative envelope gene was expressed by using a recombinant vaccinia virus carrying this region of the HCV genome. In cells infected with the recombinant vaccinia virus, a glycosylated protein with an M(r) of about 35K (gp35) was specifically detected by convalescent sera from hepatitis C patients. The sera from rabbits immunized with this recombinant vaccinia virus reacted to the gp35 produced in insect cells and also to gp35 which was translated in vitro in the glycosylated and processed form. The gp35 was used to detect antibodies in sera of only 7 to 23% of HCV patients at various stages of HCV disease. These results suggest that the gp35 of HCV may not have high antigenicity in humans.
 ...
PMID:Expression and characterization of glycoprotein gp35 of hepatitis C virus using recombinant vaccinia virus. 132 87

The identification of hepatitis C virus, based on DNA amplification, gives a precise estimation of the prevalence of the most frequent agent of NANB hepatitis. The first ELISA allowing the detection of anti-HCV antibodies, had too many false positive results and required the development of more sensitive and specific assays to confirm its results. PCR, allowing the hepatitis C virus diagnosis by showing directly HCV RNA sequences, offers a complementary approach to immunoserological tests. In blood donors with anti-HCV antibodies and with indeterminate or negative confirmatory tests, the finding of HCV RNA sequences reveals serum infectivity. During acute hepatitis, the delay in the appearance of anti HCV hampers acute phase diagnosis. The early detection of HCV RNA in peripheral blood, confirms the diagnosis and opens up therapeutic possibilities. In chronic hepatitis, the diagnosis of seronegative forms may only be resolved by PCR. Moreover, the presence of HCV RNA in peripheral blood represents the only marker of on-going viral replication and coincides with the severity of liver damage. During treatment with interferon, the follow up of HCV RNA sequences makes it possible to monitor its efficacy. The search for HCV RNA sequences directly in liver tissue shows that HCV may replicate in the liver in the absence of viremia. The presence of HCV RNA in the liver and the serum of liver transplanted patients is essential for the etiological diagnosis and management of hepatitis and bone marrow failure occurring after transplantation. Epidemiological study using PCR is a major tool in documenting vertical transmission between mother and child. Finally, PCR is important for the analysis of the HCV genome. Thus, in France there are at least three main strains, one close to the US prototype, the other close to the Japanese strain, possibly responsible for a more severe illness and a third one distinct from the previous two. However, its limits and constraints imply that PCR must not be considered as a routine assay. This emphasizes the need for more simple and rapid diagnostic tests, allowing the detection of HCV antigens and, as in hepatitis B, the progressive unravelling of the life cycle of HCV.
 ...
PMID:[Importance of PCR in the diagnosis of hepatitis C]. 132 94

In 1974, Prince et al. reported the existence of posttransfusion hepatitis with a long incubation period which was not related to hepatitis B virus (HBV). These cases were named "non-A, non-B" (NANB) hepatitis. The genome of NANB hepatitis virus was discovered recently using a recombinant complementary DNA (cDNA) approach. It was termed the hepatitis C virus (HCV), and a specific diagnostic tool for the circulating HCV antibody (anti-HCV) was developed using a purified viral polypeptide derived from recombinant yeast expressing a small part of the HCV genome. HCV is believed to be the main cause of blood-borne non-A, non-B hepatitis worldwide, which frequently evolves to chronic hepatitis and cirrhosis, and which may also be involved in the development of hepatocellular carcinoma. HCV is classified as part of the flaviviridae family and contains a positive-stranded RNA molecule by approximately 10 kb nucleotides. The HCV genome encodes a large polyprotein precursor, which is processed in structural nucleocapsid and envelope proteins and in non-structural proteins (NS1-NS5). Nucleotide sequence comparisons of distinct HCV isolates have shown a significant genetic variability between the different HCV strains. At present the diagnosis of HCV infection depends on various anti-HCV tests including second generation HCV Ab. Antigenic markers for HCV are being developed but the concentrations of HCV antigens in serum are at the lower limit of detectability by existing immunoassay technology. A polymerase chain reaction has been used to detect HCV RNA in the serum and liver. Serum HCV RNA disappears from serum after effective IFN treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:[Fundamental studies of hepatitis C virus: a review]. 133 74

We have recently developed a new colorimetric method, DNA enzyme immunoassay (DEIA), for detecting specific hybrids of complementary nucleic acids. This technology is based on an antibody that selectively recognizes double, but not single-stranded DNA. The molecule does not react with a specific probe immobilized on microwells through an avidin-biotin bridge, nor with non-specific amplified sequences, since they are removed by washing. The antibody reveals the hybridization event, independently of the DNA sequences and, for this reason, the method is broadly applicable and extremely versatile. Although we chose a format based on the immobilization of the probe through an avidin-biotin interaction, DEIA assay can also be applied to other analytical schemes that do not require any modification of the probe. Most importantly, the test has an ELISA format and is rapid and convenient for processing large numbers of samples. This technology has been applied, in our laboratory, to different areas, including virology, genetic and basic immunology. The DEIA assay has been successfully used to detect the presence of hepatitis B (HBV), hepatitis C (HCV) and hepatitis delta virus (HDV) sequences in serum of patients, to discriminate different HLA alleles, to identify mutations in the Cystic Fibrosis gene, and to investigate the role of the T cell receptor in some immunological diseases. The results obtained in all our experiments demonstrated that the advantages offered by the assay do not penalize its analytical performance as compared to conventional Southern blot.
 ...
PMID:Non-radioisotopic methods for DNA probes. 133 35

The sera of 36 French patients with post-transfusional and sporadic non-A, non-B chronic hepatitis were investigated, for HBV and HCV infections using a combination of serological and polymerase chain reaction (PCR) assays. Anti-HCV was detected in 75% (27/36) of the patients by ELISA1 and/or RIBA2 tests. HCV-RNA sequences were found in 75% (27/36) of the sera by a single step PCR, using a set of primers located in the 5' non-coding region. Altogether, 89% (32/36) of the patients were found positive with serological and/or molecular tests. Among the positive patients, 68% (22/32) were found positive for both anti-HCV and HCV-RNA, 16% (5/32) and 16% (5/32) were found positive for either anti-HCV or HCV-RNA, respectively. HBV-DNA sequences were detected in two patients associated to the HCV viraemia. This study confirms the extremely high prevalence of HCV infection in NANB chronic hepatitis in France. It also shows possible co-infection by HCV and HBV in hepatitis.
 ...
PMID:Serum hepatitis C virus RNA and hepatitis B virus DNA in non-A, non-B post-transfusional and sporadic chronic hepatitis. 133 7

Chronic infections with hepatitis B virus (HBV) of humans and animal hepadnavirus infections in their natural hosts are strongly associated with primary hepatocellular carcinoma (HCC). Although viral integrations are found in cells of many HCC, no general viral-specific hepatocarcinogenic mechanism for hepadnaviruses has been identified. In approximately one half of HCC in woodchuck hepatitis virus (WHV) infected woodchucks, viral integrations near the c-myc or N-myc genes have been reported which result in enhanced expression of the respective gene. Such host gene-specific insertional mutagenesis has not been found in HCC of other hepadnavirus infected hosts. Thus in humans, ground squirrels and ducks hepadnaviral integrations appear to be at different host chromosomal DNA sites in each HCC and few integrations have been found within or near any cellular gene. Other possible hepadnavirus-specific carcinogenic mechanisms that are being investigated include transactivation of cellular gene expression by an hepadnavirus gene product (e.g. the X-gene), and mutation of host genes by unknown hepadnavirus-specific mechanisms. It should be noted, however, that chronic hepadnavirus infection is associated with chronic necroinflammatory liver disease with hepatocellular necrosis and regeneration (sometimes leading to cirrhosis in humans), a pathological process that is common to numerous other risk factors for HCC. This suggests the possibility that this pathological process is hepatocarcinogenic irrespective of the inciting agent and the role of hepadnavirus infection is no different from that of other risk factors in causing chronic necroinflammatory liver disease.
 ...
PMID:The role of hepatitis B virus in the development of primary hepatocellular carcinoma: Part I. 133 78


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