Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.7 (DNA polymerase)
 17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A study of the e determinant of hepatitis B surface antigen in an area of hepatitis B hyperendemicity revealed that the presence of e antigen or of antibody to e in the sera of individuals was specifically related to evidence of past or present infection with hepatitis B virus. Among asymptomatic long-term carriers of hepatitis B surface antigen, presence of the e antigen was associated with elevated levels of aspartate and alanine aminotransferases in serum; this observation suggested that the e antigen might be a marker for persisting hepatic dysfunction. Higher levels of DNA polymerase found in carriers of the surface antigen with e antigen suggested that these individuals might have a higher level of circulating Dane particles and thus, perhaps, a higher level of hepatitis B virus infectivity.
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PMID:Relation of e antigen to hepatitis B virus infection in an area of hyperendemicity. 5 11

The e determinant of hepatitis B surface antigen (HBS Ag) was found in 23 of 42 patients with chronic hepatitis B virus (HBV) infection. Presence of e antigen was associated with increases in DNA polymerase activity and in the number of circulating Dane particles. In the group with detectable e antigen, the average DNA polymerase activity was 367+/-78 counts per minute (cpm; mean+/-standard error [SE]), and the average number of Dane particles counted in electron micrographs was 4.4% of the total HBS Ag. In contrast, e antigen-negative patients had an average DNA polymerase activity of 40+/-6.9 cpm (P less than 0.1) and an average Dane particle count equal to 0.6% of the HBS Ag. The e antigen was detected in 68% of patients who were HBS Ag carriers or had persistent viral hepatitis and 40% of those with chronic active type B hepatitis. Thus, the presence of e antigen correlated with both the chronicity and presence of infectious HBV. However, it did not correlate with the type or severity of liver disease after HBV infection, since e antigen was present in both chronic benign and chronic aggressive hepatitis B infections.
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PMID:Correlation of e antigen, DNA polymerase activity, and Dane particles in chronic benign and chronic active type B hepatitis infections. 6 88

A study was undertaken to assess the state of hepatitis B virus infection in a group of asymptomatic hepatitis B surface antigen (HBsAg) carriers. This study confirmed that the presence of hepatitis B e antigen (HBeAg) in serum was closely associated with serum HBsAg-specific deoxyribonucleic acid polymerase activity, hepatitis B core antigen (HBcAg) in serum and liver cell nuclei, and a histological picture of chronic hepatitis. No HBsAg-specific deoxyribonucleic acid polymerase activity or HBcAg was detected in highly concentrated anti-HBe-positive sera. In addition, liver biopsy specimens from carriers with anti-HBe were negative for HbcAg by immunofluorescence, and the liver histology was either normal or revealed only fatty changes. These data indicate that the anti-HBe-positive sera contained either no Dane particles or, if present, at least a 500-fold-lower concentration of Dane particles than that found in HBeAg-positive sera.
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PMID:Expression of hepatitis B virus-specific markers in asymptomatic hepatitis B surface antigen carriers. 7 Dec 67

Twelve infants, born to mothers with hepatitis B virus infection, were inoculated within 7 days of birth with immune serum globulin containing antibody to hepatitis B surface antigen (HBsAg) titers of 1:32 to 1:64 as measured by passive hemagglutination. Six of nine infants (66.7%) born to HBsAg-positive carrier mothers became HBsAg-positive within 3 mo of age. In addition, two of three treated infants born to mothers with acute hepatitis B during the delivery period also developed HBsAg. The hepatitis e antigen was detected in four of five carrier mothers and in two mothers with acute hepatitis, whose infants subsequently became HBsAg positive. In addition, hepatitis B-specific DNA polymerase activity was detected in the seven HBsAg-positive mothers who transmitted the virus to their infants. All eight infants have remained persistently HBsAg positive. Thus, the immune serum globulin containing low-titer antibody to HBsAg is not protective when given to infants born to HBsAg carrier mothers or to mothers with acute hepatitis B during the delivery period.
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PMID:Failure of immune serum globulin to prevent hepatitis B virus infection in infants born to HBsAg-positive mothers. 8 62

Partially purified hepatitis B e antigen (HBeAG) was prepared by ultracentrifugation, ammonium sulfate precipitation, and molecular sieve chromatography of sera obtained from asymptomatic carriers of hepatitis B surface antigen. The antigenic specificity of the HBeAG preparations was investigated further with affinity chromatography. The results indicated that HBeAG is distinct and separable from DNA polymerase activity. Columns coupled with either goat IgG prepared from antiserum to human IgG or antibody to HBeAg bound all detectable HBeAg and bound 31% and 100% of the IgG, respectively, from a partially purified HBeAg preparation. Rate zonal sucrose sedimentation and molecular sieve and ion-exchange chromatography indicated a variability in molecular weight and charge; this finding suggested a heterogenous population of immunoreactivities containing HBeAg. Our preliminary results suggest the existence of an HBeAg-IgG complex.
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PMID:A partial characterization of hepatitis B e antigen. 8 89

The hepatitis B virus (HBV), the causal agent of serum hepatitis, has a diameter of 42 nm and is comprised of an outer surface coat and a 27 nm core. A unique DNA-dependent DNA polymerase is associated with the core of the virus. The core also houses a circular DNA that contains both double-stranded and single-stranded regions. In the endogenous reaction, the DNA polymerase repairs the single-stranded gaps of the viral DNA. The surface protein of the virus, called hepatitis B surface antigen, contains both lipid and carbohydrate, and is often present in particulate form in the blood of infected patients. In Asia and Africa HBV infection is associated with subsequent development of primary hepatocellular carcinoma. Although most patients recover completely from acute illness, the hepatitis B virus may cause chronic infection. Recently, a virus similar to human HBV was discovered in woodchucks. HBV has not yet been propagated in a cell culture system and the mode of replication of this unusual virus in hepatocytes is still moot. Although reliable therapy has not yet been provided, the problem of this world-wide infection has led to many interesting approaches to both vaccine production and anti-viral chemotherapy.
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PMID:The hepatitis B virus and its DNA polymerase: the prototype three-D virus. 9 Oct 92

Six patients with hepatitis B surface antigen, hepatitis B 'e' antigen positive chronic active hepatitis, and elevated hepatitis B specific DNA polymerase activity were treated sequentially with fibroblast and leucocyte interferon. Fibroblast interferon induced a fall in serum transaminase activities in all patients, whereas a consistent decline in DNA polymerase activity was observed during leucocyte interferon administration only. After treatment one patient remained persistently DNA polymerase and hepatitis B 'e' antigen negative, whereas relapse to initial values occurred in others. Side effects included severe but reversible granulocytopenia, and chills responding to promethazine treatment. The differential biologies with their non-identity in in vitro studies.
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PMID:Differential effects of fibroblast and leucocyte interferon in HBsAg positive chronic active hepatitis. 11 47

Hepatitis B virus-like particles (including DANE particles) with DNA polymerase activity but negative for HBs Ag have been identified in NON-A, NON-B hepatitis sera positive for HC Ag. Although specifically associated with the particles, HC Ag is not a surface antigen of the hepatitis C virus identified here for the first time. The relationship of this agent with HBV seems obvious, and deserves further study.
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PMID:[Identification of a virus similar to hepatitis B virus in non-A non-B hepatitis]. 12 Jul 82

Resulting directly from the discovery of virus-related antigens, rapid progress has marked the last decade of viral hepatitis research. The hepatitis B virion has been tentatively identified as a DNA virus with an endogenous DNA polymerase, and new serological markers for type B hepatitis have been discovered. Hepatitis A antigen has been identified on a virus-like particle thought to be the hepatitis A virion. Progressively more sophisticated assays for hepatitis antigens and antibodies have been applied to the study of viral hepatitis epidemiology and biochemical-biophysical characterization of the agents. Most recently, knowledge learned from such studies has been exploited to develop a prototype non-infectious but immunogenic hepatitis B vaccine using hepatitis B surface antigen (HBsAg) purified in large quantities from chronic HBsAg carriers. Especially exciting is the prospect, suggested by serological studies of viral hepatitis, that hepatitis viruses besides hepatitis A and B viruses will be identified.
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PMID:Recent advances in the identification of hepatitis viruses. 19 74

DNA of hepatitis B virus (HBV) of hepatitis B surface antigen (HBsAg) subtype adw2 made fully double stranded by the virion DNA polymerase and radiolabeled either by the virion DNA polymerase reaction or by nick-translation with 32P-labeled deoxynucleoside triphosphates was used to establish a map of restriction endonuclease cleavage sites by the method double and triple enzyme digestion and to determine the relative positions of several unique physical features of this DNA. The five restriction sites for enzyme HincII, the two sites each for BamHI, Ava I, and Bgl II, and the single sites for EcoRI, Pst I, Hpa I, and Taq I were positioned relative to each other. Within this map, the single-stranded region in HBV DNA has been localized and the locations of nicks in each strand (a and b) have been determined with respect to restriction sites on the circular map. Comparison of restriction endonuclease cleavage patterns of DNAs of HBV of HBsAg subtypes adw2, ayw3, and adrq+ revealed consistent differences among subtypes and occasional differences within subtypes.
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PMID:Restriction endonuclease cleavage map and location of unique features of the DNA of hepatitis B virus, subtype adw2. 29 95


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