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

Several different hepatic parenchymal lesions, including chronic hepatitis and cirrhosis, have been increasingly reported in children with schistosomal hepatic fibrosis (SHF) despite the known mesenchymal nature of the disease. The prevalence of persistent hepatitis (B) surface (HBs) antigenaemia and some hepatic functions have been determined in 52 children with SHF as well as in 100 age-matched healthy children. High prevalence of chronic HBs antigenaemia (58 per cent) has been demonstrated in children with SHF, but only in 2 per cent of the normal children. This denotes that children with SHF represent a dangerous reservoir for hepatitis B infection to the community. Serum alanine transferase (ALT) was higher than normal in 58 per cent of HBS seropositive patients and in none of the seronegative patients. This points to the risk of continual hepatic parenchymal injury to the HBs seropositive patients with schistosomiasis.
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PMID:Study on some hepatic functions and prevalence of hepatitis B surface antigenaemia in Egyptian children with schistosomal hepatic fibrosis. 236 12

Hepatitis B surface antigen possesses the group-specific determinant called a and one or another member from each of two pairs of allelic determinants, d and y as well as w and r, thereby creating the four major subtypes, adw, adr, ayw and ayr. In the sequence of major surface antigen polypeptides made of 226 amino acid residues, lysine or arginine at amino acid position 122 specifies d or y determinant, and lysine or arginine at position 160 specifies w or r determinant, respectively. By means of site-directed mutagenesis and expression of mutant genes in cultured cells, the mechanism for the loss of subtypic determinants on surface antigens was investigated at the molecular level. A rare sample of surface antigen of subtype ad, devoid of w or r determinant, had asparagine at position 160. When it was converted to lysine, the surface antigen of subtype adw was obtained. Two samples of surface antigen were subtyped as ar. They lacked d determinant, despite having lysine at position 122 which usually specified it. They differed from all reported sequences of surface antigen in amino acid 144 or 145. They displayed d determinant when amino acid 144 was converted from glutamic acid to aspartic acid, or when amino acid 145 was changed from alanine to glycine. These results indicate that the key amino acid residue at position 122 or 160 is indispensable for the expression of subtypic determinants and that some distant residues are also crucially involved in conforming them.
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PMID:The loss of subtypic determinants in alleles, d/y or w/r, on hepatitis B surface antigen. 246 92

Residues 120-131 within the hepatitis B core Ag (HBcAg) represent a dominant T cell recognition site for mice of the H-2S haplotype. This study was undertaken in order to identify residues within the p120-131 sequence which either interact with the TCR termed epitopic residues or interact with MHC class II molecules termed agretopic residues. For this purpose a panel of analogs of p120-131 composed of peptides containing single alanine substitutions for each residue was synthesized. These peptides were analyzed functionally for their ability to stimulate p120-131 or HBcAg-primed T cells and for their immunogenicity in B10.S or [B10.S X B10 (nonresponder)]F1 mice. Furthermore, analogs of p120-131 were used as stimulators and inhibitors of T cell activation in competitive inhibition experiments. Cumulatively these functional studies allowed us to identify residue 125 as a dominant epitopic residue and residues 127 and 129 as dominant agretopic residues. Furthermore, a p120-131 analog containing an alanine substitution for the dominant agretopic residue was immunogenic in B10.S mice, but was nonimmunogenic in (B10.S X B10)F1 mice indicating that T cell responsiveness is influenced by MHC class II gene dosage effects and can be inherited in an apparent recessive manner. In this study, critical residues involved in the immunogenicity of this dominant T cell determinant of HBcAg were defined, in a companion study, the influence of these residues on tolerogenicity was examined.
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PMID:Functional identification of agretopic and epitopic residues within an HBcAg T cell determinant. 247 18

To determine the influence of concurrent human immunodeficiency virus (HIV) infection on chronic hepatitis B virus (HBV) infection, 150 male homosexual chronic hepatitis B surface antigen (HBsAg) carriers were studied. Of these, 82 subjects (55%) tested positive for antibodies to HIV. They were more likely to express hepatitis B "e" antigen (HBeAg) (P less than .001) and HBV-DNA (P less than .0005) in serum than were HIV-seronegative individuals. However, the degree of immune suppression did not influence HBeAg-HBV-DNA expression. In HBeAg-seropositive subjects, concurrent HIV infection was associated with lower serum alanine transferase levels (P less than .001). This effect increased with the degree of immune suppression as determined by CD4+ lymphocyte counts. Conversely, in patients negative for HBeAg, there was a weak trend towards higher alanine transferase levels with concurrent HIV. This study suggests that chronic hepatitis B may be less severe when accompanied by HIV infection; however, greater viral replication may make it more contagious and resistant to antiviral therapy. These data support an immune-mediated pathogenesis for hepatitis B and have implications for its control.
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PMID:The effect of concurrent human immunodeficiency virus infection on chronic hepatitis B: a study of 150 homosexual men. 257 46

Forty four patients with various forms of pulmonary tuberculosis in association with virus hepatitis B (21) and toxic-allergic hepatitis (23) were followed up in the time course of the diseases. There was a marked clinical similarity between toxic-allergic hepatitis and virus hepatitis B which differed in their qualitative indices and duration. Differential diagnosis of virus hepatitis B and toxic-allergic hepatitis was possible on the basis of the clinical signs and routine tests: determination of bilirubin and its fractions in blood, estimation of activity of alanine and aspartate aminotransferases and case follow-up with an account of the epidemiological situation.
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PMID:[Toxic-allergic and viral hepatitis in patients with pulmonary tuberculosis]. 262 75

The incidence of post-transfusion hepatitis (PTH) in recipients of blood products is reviewed. PTH was observed in 10%-12% of recipients of blood products in the United States, 2%-4% in northern Europe and 15%-20% in southern Europe. All studies indicate that 80%-90% of all PTH cases are attributed to non-A/non-B. At least 40% of the patients with PTH non-A/non-B will develop chronic hepatitis or cirrhosis. No specific tests for the detection of the non-A/non-B agent(s) exist. However, several independent studies indicate that part of the donors carrying the infectious non-A/non-B agent have increased levels of alanine amino transferase (ALT). When donors are excluded with elevated ALT values, it is estimated that about 30% of the PTH non-A/non-B cases would be prevented. Some studies indicate that anti-hepatitis B core (anti-HBc) positive donors may carry an increased risk to transmit the non-A/non-B agent, but more recent studies do not confirm this. There is hope that a specific non-A/non-B test will be developed soon.
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PMID:Blood transfusion and hepatitis: still a threat? 264 93

The hepatitis B virus (HBV) C gene directs the synthesis of two major gene products: HBV core antigen (HBcAg[p21c]), which forms the nucleocapsid, and HBV e antigen (HBeAg [p17e]), a secreted antigen that is produced by several processing events during its maturation. These proteins contain an amino acid sequence similar to the active-site residues of aspartic acid and retroviral proteases. On the basis of this sequence similarity, which is highly conserved among mammalian hepadnaviruses, a model has been put forward according to which processing to HBeAg is due to self-cleavage of p21c involving the proteaselike sequence. Using site-directed mutagenesis in conjunction with transient expression of HBV proteins in the human hepatoma cell line HepG2, we tested this hypothesis. Our results with HBV mutants in which one or two of the conserved amino acids have been replaced by others suggest strongly that processing to HBeAg does not depend on the presence of an intact proteaselike sequence in the core protein. Attempts to detect an influence of this sequence on the processing of HBV P gene products into enzymatically active viral polymerase also gave no conclusive evidence for the existence of an HBV protease. Mutations replacing the putatively essential aspartic acid showed little effect on polymerase activity. Additional substitution of the likewise conserved threonine residue by alanine, in contrast, almost abolished the activity of the polymerase. We conclude that an HBV protease, if it exists, is functionally different from aspartic acid and retroviral proteases.
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PMID:Proteaselike sequence in hepatitis B virus core antigen is not required for e antigen generation and may not be part of an aspartic acid-type protease. 265 1

To clarify the relationship between the pre-S antigens and other serological markers of hepatitis B virus (HBV) replication, we followed up 27 patients: 21 presented with symptoms of acute hepatitis (two progressed to chronicity) and six suffered from chronic hepatitis. Pre-S1, pre-S2, HBV DNA, IgM antihepatitis core antigen (HBc), hepatitis B e antigen (HBeAg), and anti-HBe were detected in about 200 sera serially collected at different times for at least 6-12 months from the onset of clinical observation. In the early symptomatic phase of acute hepatitis, the pre-S1 and pre-S2 antigens were present in 95% of the cases and correlated well with high levels of alanine-transferase (ALT) and IgM anti-HBc, while HBV DNA was present in the sera of only six (28.6%) patients (P less than 0.0001). This was the first marker to disappear (1 month after the initial stage). All of the HBV DNA-positive patients were also HBeAg positive, whereas no HBeAg-negative subjects were found with serum HBV DNA. In the six chronic patients, pre-S antigens were always present independently of the HBeAg/anti-HBe status; HBV DNA was detected in three of them, even if transiently, and in two of these it reappeared together with pre-S2 epitope. The follow-up data suggest that, in acute hepatitis, the clearance of pre-S antigens can be considered as a prognostic index of clinical resolution and that, in chronic hepatitis, the persistence of pre-S antigens seems to indicate progression of the disease. In particular, pre-S2, in patients in whom it is intermittent, can be considered as an index of reactivation.
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PMID:Clearance of hepatitis B virus DNA and pre-S surface antigens in patients with markers of acute viral replication. 275 27

Conventional HBV serological markers, as well as serum alanine amino transferase and hepatitis B virus DNA (HBV DNA) were studied in a population of 667 institutionalized mentally handicapped males and females and in 676 staff members. The role of Down's syndrome (DS), sex and age-related factors with respect to the prevalence of these markers was analyzed. A young age at admission was found as one of the important factors in the development of the chronic HBsAg carrier state in females. The well-known higher prevalence of HBsAg carriership in DS patients appeared to be restricted to males. Markers indicative of viral replication, HBeAg and HBV DNA, were also more prevalent in male than in female DS residents, or OMR residents. These findings indicate that the phase of active viral replication is prolonged in male HBsAg carriers with DS. However, only 66.7 per cent of HBV DNA-positive and 26.2 per cent of HBsAg-positive residents had abnormal serum alanine aminotransferase (ALT) values. In addition, more than 50 per cent of residents with elevated serum alanine amino transferase values were negative for HBV serological markers. We conclude that male DS residents are the main source of HBV infection in institutions for the mentally handicapped and that determination of ALT values is not very useful in identifying those HBsAg carriers capable of transmission the infection.
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PMID:The prevalence of serological markers, hepatitis B virus DNA and elevated serum amino transferase values in institutionalized mentally handicapped males and females: an epidemiological study of HBV infection in residents with Down's syndrome or other forms of mental deficiency. 297 57

A community survey was undertaken in order to determine the seroepidemiologic pattern of acute viral hepatitis in Auckland. As hospital records and Health Department notifications underestimate the problem, all patients with a serum alanine transpeptidase (ALT) level of greater than 200 mu/l (X 5 normal) were investigated for viral liver disease. Over a four month period a total of 303 cases of acute viral hepatitis were identified, 49 (16.2%) were hepatitis A, 11 with coincident hepatitis B, 88 (29%) were hepatitis B, 80 (26.4%) nonA nonB hepatitis, 81 (26.7%) Epstein Barr virus hepatitis and 5 (1.6%) cytomegalovirus hepatitis. Hepatitis A and hepatitis B occurred with increased frequency among Maoris and Polynesians, while Epstein Barr virus, cytomegalovirus and nonA nonB hepatitis occurred more frequently among Europeans. The incidence of acute symptomatic viral hepatitis (excluding cytomegalovirus and Epstein Barr virus infections) was 78 cases/10(5)/per year for the Auckland region in this survey.
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PMID:Acute viral hepatitis in Auckland. 303 65


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