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 clinical significance of the high prevalence of antibodies to hepatitis C virus (HCV) in dialysis patients remains undefined. In order to assess the relationship between seropositivity and potential infectivity, 63 patients undergoing maintenance hemodialysis were evaluated between April and May 1990. The mean duration of maintenance hemodialysis was 45 mo (range, 13 to 144). Eighty-two percent (52 of 63) had received blood transfusions, and 16% (10 of 63) had a history of iv drug abuse. Serum samples were analyzed by HCV-cDNA polymerase chain reaction; antibodies to HCV structural (core) and nonstructural regions NS3 and NS4 were determined by enzyme immunoassay. Specimens repeatedly reactive for anti-HCV and HCV-RNA-positive samples were tested by HCV MATRIX dot immunoblot assay and HBV-DNA PCR. Twenty-five percent (16 of 63) were anti-HCV-positive. Of the 16 anti-HCV-positive patients, HCV-RNA was detected in 5 (31%) with the NS3 primers and in 12 (75%) with 5'-noncoding primers. Among the anti-HCV-negative patients, HCV-RNA was detected in 2 (4.3%) of 47 patients. Eleven of the 18 patients with HCV infection (anti-HCV and/or HCV-RNA-positive) had evidence of additional present or past viral infections (human immunodeficiency virus and/or hepatitis B virus). In summary, HCV-RNA is present in at least 75% of anti-HCV-positive patients, suggesting that they may be infectious. The detection of HCV-RNA in anti-HCV-negative patients may indicate early or chronic HCV infection not detected by current antibody assays or the inability of these patients to mount or sustain a significant antibody response.
 ...
PMID:Detection of hepatitis C virus RNA in hemodialysis patients. 751 32

We assessed the correlation between hepatitis C virus replication and antibody responses toward hepatitis C virus core (C22-3), NS3 (C33C), NS4 (5-1-1 and C100-3) and NS5 proteins in 59 virus carriers. The concentration of serum hepatitis C virus RNA was determined by a competitive reverse transcription-polymerase chain reaction assay. All 50 patients with high viremic levels of > or = 10(6) copies/mL had antibodies to C22-3 and C33C. Antibodies to 5-1-1, C100-3 and NS5 proteins were detected less frequently (p < 0.01) in 72% (36 of 50), 78% (39 of 50) and 84% (32 of 38) of such patients, respectively. As for the nine patients with low viremic levels of < 10(6) copies/mL, antibodies to C22-3, C33C, 5-1-1 and NS5 proteins were detected in only one patient (11%), which was significantly less than the frequency for highly viremic patients (p < 0.01). Antibody to C100-3 was also found less frequently in only four patients (44%) (p < 0.05). Thus, only four (44%) of the nine low viremic patients tested positive for any antibody compared with all 50 highly viremic patients (p < 0.01). These results indicate that highly viremic carriers can be detected by the presence of hepatitis C virus antibodies, but a considerable proportion of low viremic carriers may not show any serological evidence of hepatitis C virus infection.
 ...
PMID:Hepatitis C virus replication and antibody responses toward specific hepatitis C virus proteins. 751 60

The role of hepatitis C virus (HCV) infection in fulminant hepatic failure is controversial. The frequency of serum HCV RNA positivity in previously reported patients with fulminant hepatic failure (FHF) of indeterminate cause ranged from 0 to 12% in the United States and Europe and from 43% to 59% in Asia. We assessed serum HCV RNA using polymerase chain reaction (PCR) and oligoprimers from the 5'UTR of the HCV genome in 26 consecutive patients with FHF. Another laboratory independently performed PCR on 21 of the serum samples using different oligoprimers from the 5'UTR and NS3 region of the HCV genome. Serum HCV RNA was detected in two of seven (28%) patients with hepatitis B, 9 of 15 (60%) with an indeterminate cause, and in none with hepatitis A (n = 2) or drug-induced hepatotoxicity (n = 2). HCV RNA PCR results were concordant between both laboratories in 17 of 21 (81%) of samples. In patients with an indeterminate cause, HCV RNA positivity was significantly associated with the transmission risk factor of low socioeconomic status and Hispanic ethnicity. Eighteen patients underwent liver transplantation (LT) and 15 (83%) survived. Among patients with FHF of indeterminate cause, recurrent or acquired HCV infection after transplantation occurred in three of five (60%) and one of four (25%) patients, respectively. Three of four (75%) patients with hepatitis C virus infection post-LT also developed histologic hepatitis. HCV appears to be the causative agent of a substantial number of cases of FHF classified as indeterminate in the Los Angeles area. Differences in patient populations or risk factors may explain the discordant incidences of HCV infection in FHF observed among different programs.
 ...
PMID:Detection of hepatitis C virus with RNA polymerase chain reaction in fulminant hepatic failure. 759 Jun 51

The mechanisms by which pX, the transactivator of the hepatitis B virus (HBV), exerts its effects on transcription of viral and cellular genes and affects cell-growth regulation have not yet been fully defined. Previous reports suggested the possibility of a direct interaction of pX, which lacks intrinsic DNA-binding activity, with components of the cellular transcription machinery. More recent investigations support the hypothesis that pX might activate cellular kinases involved in transcriptional regulation and growth control. We characterized the mechanisms of AP-1 transcription factor activation by pX and, in particular, the role of cellular proteins involved in the intracellular signal transduction of growth-factor receptors. The observation that the overexpression of c-fos and c-jun in the cells results in a clear augmentation of the effects of pX on TRE-directed transcription and the induction of the DNA-binding activity of c-jun/c-fos heterodimers by AP1-depleted nuclear extracts from pX-expressing cells strongly supports the involvement of post-translational modifications. In both HeLa and undifferentiated F9 cells, pX was able to increase the activity of exogenous transfected c-jun but not of c-jun mutants bearing mutations in the serine residues located in the amino-terminal transcriptional activation domain. Moreover, by use of Ha-ras and Raf-1 dominant negative mutants, we show that both Ha-ras and Raf-1 are required for pX-induced activation of c-jun transcriptional activity.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Modulation of intracellular signal transduction pathways by the hepatitis B virus transactivator pX. 760 67

The detection of antibody to the hepatitis C virus C100-3 antigen from the nonstructural region (NS3/NS4) of the viral genome was the first useful marker developed to detect past or potentially active infection with the hepatitis C virus. A systematic epitope survey of the nonstructural region has uncovered other immunogenic antigens. In order to assess the possible diagnostic utility of these antigens, their reactivity against a limited panel of sera from patients with chronic liver disease due to hepatitis C virus and other etiologies was tested. Antibody assays were performed using an immunoblot plaque assay and an enzyme-linked immunosorbent assay (ELISA). In a study of 16 C100-3-reactive individuals, all 16 patients were reactive using the plaque assay for the NS3 3' (409-1-1) and NS3 5' (C33u). In this same group of patients, antibodies by ELISA were reactive to NS3 3' in 12 of 16 patients (75%), NS3 5' in 15 of 16 patients (93%), and a capsid antigen (NC450) in 14 of 16 patients. In a group of five patients who were diagnosed with cryptogenic liver disease (C100-3 negative), 4 of 5 patients were reactive for antibody to all of the above epitopes. In a survey of 23 patients with other forms of chronic liver disease (nonviral liver disease, hepatitis B, alcoholic liver disease, cholestatic liver disease, and autoimmune hepatitis), only 1 of 23 patients was reactive for antibody to the C100-3 and 4 of 23 patients were reactive for antibodies to structural and nonstructural regions of the virus.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Variation in antibody reactivity to the hepatitis C virus by comparative immunoscreening and enzyme immunoassay. 768 14

Hepatitis C virus (HCV) antigen expression was examined by immunohistochemical staining in liver tissue taken at biopsy from 8 anti-HCV positive patients. Frozen liver sections were stained by indirect immunofluorescence for capsid, E2/NS1, NS3, NS4 and NS5 using polyclonal antibodies raised to synthetic peptides from these regions. The antigens E2 and NS3 were localised in scattered hepatocytes and also in cells within and around areas of inflammation. A weaker signal was observed for NS4 and NS5 and no signal was seen for capsid antigen. No staining was seen in liver tissue from 9 individuals, including 3 hepatitis B virus-positive and 2 hepatitis delta virus/positive patients, who were negative for serological markers of HCV. The specificity of the staining reaction was also confirmed by the lack of staining in HCV-positive liver samples, after the antisera was pre-adsorbed against the specific peptide. Collectively, the data suggests that HCV may not only be hepatotropic but also lymphotropic, and this may be an important factor in the pathogenesis of HCV infection.
 ...
PMID:Localisation of hepatitis C virus proteins in infected liver tissue by immunofluorescence. 768 8

The serodiagnosis of hepatitis C virus (HCV) infection was analyzed by a recombinant immunoblot assay (RIBA) with recombinant proteins encoded by the viral RNA isolated from our patients in Hamburg, Germany. The HCV RNA was amplified by PCR, and proteins encoded by the viral core and the NS3, NS4, and NS5 regions were expressed subsequently in Escherichia coli. The results obtained with our UKE RIBA were compared with the results of the Abbott HCV second-generation enzyme immunoassay (EIA). Serum samples from 270 patients, which were sent to us on the suspicion of HCV hepatitis and which were negative for hepatitis A virus and hepatitis B virus antibodies, were examined. In 227 cases (84.1%), there were identical positive (204 cases, 75.6%) or negative (23 cases, 8.5%) results in both tests. In 32 cases (11.9%), the reactive Abbott second-generation HCV EIA results could not be confirmed by the UKE RIBA and the HCV PCR. In follow-up studies conducted over 1 year, these results did not change. In three cases (1.1%), the UKE RIBA presented a positive result while the Abbott second-generation HCV EIA was negative. All three cases were positive in the HCV PCR and showed seroconversion in an HCV EIA 4 to 6 weeks later. In addition, 33 patient serum samples were examined by UKE RIBA in parallel with the Ortho RIBA 2.0. In three cases (9.1%), a positive Ortho RIBA 2.0 result could not be confirmed by the UKE RIBA and the HCV PCR. All three patients were free of complaints. The UKE RIBA showed also a smaller number of indeterminate results (3.0%) than the Ortho RIBA 2.0 (24.2%). This comparison study demonstrates that the commercially available HCV antibody tests should be further improved.
 ...
PMID:Study on reliability of commercially available hepatitis C virus antibody tests. 775 66

The prevalence of hepatitis C virus (HCV) in Libya has been investigated by seeking evidence of HCV infection in 266 healthy Libyan subjects (147 females, 119 males; age range 1-78 years), 76 of whom were registered blood donors. None had any history of blood transfusions, surgery, homosexuality, drug misuse or other risk factor for viral hepatitis. Sera from all subjects were tested for anti-HCV antibodies by enzyme-linked immunosorbent assay against synthetic structural and non-structural HCV peptides from the HCV core, envelope, NS1, NS3/NS4 and NS5 regions. Eighteen (6.8%), all of whom were seronegative for hepatitis B surface antigen (HBsAg), were found to be anti-HCV positive (including 5 blood donors). The patterns of reactivity against the individual peptides varied between subjects as follows: core (14 subjects), envelope (11), NS1 (9), NS3/NS4 (10), and NS5 (6). Fourteen of the 18 had elevated serum aminotransferase activities (AST/ALT) but so also did 9 other subjects who were seronegative for both HBsAg and anti-HCV. Twelve of the 18 anti-HCV positive subjects, including 3 of the 5 anti-HCV positive blood donors, had circulating HCV RNA detected by the polymerase chain reaction. HCV RNA was also detected in 3 of the 9 anti-HCV negative cases with elevated AST/ALT. The finding that 21 (7.9%) of the 266 subjects had evidence of HCV infection indicates that there is a very high frequency of 'community-acquired' HCV in the normal Libyan population, and this has major implications for blood transfusion in that country.
 ...
PMID:High prevalence of hepatitis C virus in the normal Libyan population. 797 63

Chronic infection with hepatitis B virus (HBV) is accompanied by an increasing risk of developing hepatocellular carcinoma. There are indications that the HBx protein of HBV is involved in the process of tumour formation. HBx also transactivates several transcription factor binding sites. Recently, we reported that HBx can use a tumour promotor pathway for transactivation. In particular, we found that transactivation of the binding motif for transcription factor AP-1 (JUN/FOS) by HBx is dependent on functional protein kinase C (PKC), as indicated by abolition of the transcriptional stimulation following downregulation or inhibition of the enzyme. Moreover, HBx activates PKC, probably via increasing the endogenous PKC activator sn-1,2-diacylglycerol (DAG). Here we extend these data and report on the time course of PKC activation. We found that activation of PKC by HBx is transient and differs from activation of PKC by the ras oncogene product or phorbol ester in that it does not lead to rapid downregulation of the enzyme subsequent to the activation. Moreover, we provide evidence that an increase in cellular DAG is observable not only as an early event in response to HBx but also in cell lines transformed after transfection with HBV DNA and stably expressing HBx. Besides its important role in the regulation of cellular genes, PKC is also the intracellular receptor for tumour-promoting agents and an activator of proto-oncogenes, suggesting that our observations might provide an explanation for the oncogenic properties of HBx.
 ...
PMID:The hepatitis B virus transactivator HBx causes elevation of diacylglycerol and activation of protein kinase C. 821 Jul 15

Insertional mutagenesis of growth related genes by hepatitis B virus (HBV) DNA is presumed to play a role in hepatocarcinogenesis. Here, we report on insertional activation of the mevalonate kinase (MK) gene in the human hepatoma cell line PLC/PRF/5. Integration of HBV DNA dissociated the promoter and upstream regulatory elements of the gene from its coding sequences. This led to the over-expression of hybrid transcripts arising from an HBV promoter and the consequent over-production of functionally active mevalonate kinase. MK phosphorylates mevalonate, a major intermediate in the branched cholesterol/isoprenoid biosynthetic pathway. Isoprenylation is crucial to the functions of cellular proteins related to growth control, including the proto-oncogene ras. As the enzymes of these biosynthetic pathways are regulated at multiple points by negative feedback, both transcriptionally and at the protein level, the results discussed here support the idea that aberrant growth could result from deregulated overexpression of MK and, perhaps, other enzymes in the cholesterol pathway. These results invoke novel mechanisms by which cell transformation might occur.
 ...
PMID:Insertional activation of mevalonate kinase by hepatitis B virus DNA in a human hepatoma cell line. 830 6


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