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)

Radioactive DNA was prepared in extensive (4 h) Dane particle DNA polymerase reactions. In different experiments the amount of new DNA, determined by the amount of nucleotide incorporation into an acid-insoluble form, was between 29 and 45% of the total circular DNA isolated from Dane particle preparations after the reaction. DNA reassociation kinetics were used to determine the complexity of the newly synthesized DNA. In different experiments COt1/2 values, corresponding to between 625 and 1,250 nucleotide pairs, were obtained for the radioactive Dane particle DNA. These results suggest that a unique region (or regions), corresponsing to approximately one-fourth to one-half of the circular Dane particle DNA template, was copied one time during the reaction. DNA and RNA extracted from hepatitis B virus-infected liver but not from uninfected liver accelerated the rate of reassociation of radioactive DNA from Dane particles. These Dane particle DNA base sequences were found in alkali-stable, rapidly sedimenting DNA from infected liver as well as in DNA sedimenting at a rate similar to the DNA extracted from Dane particles. These findings are consistent with Dane particle DNA being hepatitis B virus DNA that is integrated into high-molecular-weight cellular DNA and transcribed into RNA in infected liver.
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PMID:DNA synthesized in the hepatitis B Dane particle DNA polymerase reaction. 83 33

DNA isolated from the hepatitis B antigen form known as the Dane particle was examined by electron microscopy before and after the endogenous Dane particle DNA polymerase reaction. The most frequently occurring form was an untwisted circular double-stranded DNA molecule approximately 1 mum in length. Less frequently occurring forms included circular DNA of approximately unit length and having one or more small single-stranded regions, similar circular molecules with one or more tails either shorter or longer than 1 mum in length, and very small circular molecules with tails. There was no increase in frequency or length of tails after a DNA polymerase reaction, suggesting that tails were not formed during this reaction. The mean length of circular molecules increased by 23% when DNA was spread in formamide compared with aqueous spreading, suggesting that single-stranded regions are present in most of the molecules. The mean length of circular molecules obtained from aqueous spreading increased by 27% after a Dane particle DNA polymerase reaction. This indicates that single-stranded regions were converted to double-stranded DNA during the reaction.
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PMID:Structure of hepatitis B Dane particle DNA before and after the Dane particle DNA polymerase reaction. 83 42

We have studied prospectively 178 subjects exposed to hepatitis B and 120 haemodialysed patients for the presence of HGs antigen, e antigen and DNA polymerase as well as for anti-HBs and anti-HBc antibodies. The results suggest that the DNA polymerase assay enables us to diagnose hepatitis B earlier than the radioimmunoassay for HGs and that DNA polymerase might be present in the blood in the absence of HBs in cases of confirmed hepatitis B. A posititive correlation between e antigen and DNA polymerase was observed in 83% of the patients on haemodialysis who developed hepatitis B but only in 9% of normal patients developing the same disease.
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PMID:Early diagnosis of Hepatitis B by Dane particle associated DNA polymerase assay. 88 1

Hepatitis B core antigen (HBcAg) was purified from Dane particles and from infected hepatocytes. An identical isoelectric pH of 4.0 was determined for labeled preparations of both Dane-derived and liver-derived HBcAg. Unlabeled liver-derived HBcAg demonstrated a lower isoelectric pH of 3.7. Molecular weight determinations by Sepharose 4B column chromatogrpahy revealed that liver-derived HBcAg had a molecular weight of 8.5-9.0 X 10(6) daltons. The sedimentation coeficient of both Dane- and liver-derived HBcAg was found to be 124S. PAGE revealed that iodinated HBcAg derived from Dane particles was very similar in polypeptide structure to HBcAg derived from infected liver tissue. Twelve polypeptides were resolved from Dane core particles, and seven to nine were resolved from liver core particles. Several of the polypeptides in both preparations co-migrated with iodinated hepatitis B surface antigen (HBsAg). However, three polypeptides (mol. wt. 88,000, 79,000 and 59,000) were found in both Dane- and liver-derived HBcAg but not in HBsAg, which suggests that these polypeptides are HBcAg-specific. Endogenous DNA polymerase activity was observed in both Dane- and liver-derived core particles.
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PMID:Biochemical and biophysical properties of hepatitis B core particles derived from Dane particles and infected hepatocytes. 89 38

A high positive correlation was found between e antigen (HBe Ag) and DNA polymerase in hemodialyzed patients with acute hepatitis B, chronic carriers of hepatitis B surface antigen undergoing hemodialysis, and patients with chronic hepatitis. In contrast, the correlation was poor in nonhemodialyzed patients with acute hepatitis. Among the patients with chronic hepatitis, HBe Ag and DNA polymerase were were found mostly in those with aggressive hepatitis and rarely in those with persistent hepatitis. This difference was significant (P less than 0.01) and suggests that the persistence of these antigens may be a factor in the progression of the disease. Our data also indicate that the development of antibodies to HBe Ag (anti-HBe) might be a sign of a favorable prognosis, since 50% of the patients with persistent hepatitis vs. 6% of the patients with aggressive hepatitis were anti-HBe-positive. Inhibitors of DNA polymerase, which are possibly antibodies, appeared regularly after acute hepatitis and were transient. Their presence may be associated with viral replication.
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PMID:e antigen and antibody, DNA polymerase, and inhibitors of DNA polymerase in acute and chronic hepatitis. 91 41

Thirty-nine carriers of hepatitis B surface antigen (HBs Ag) were studied with respect to e antigen and Dane particle-associated DNA polymerase activity and their relation to chronic hepatitis. Most of these individuals were followed for four or five years. A strong correlation between e antigen and DNA polymerase activity was found. Of the 22 e antigen-positive patients, 21 showed polymerase activity; none of the 13 e antigen-negative patients (one of whom had antibody to e antigen) had such activity. Three of four patients who became e antigen-negative after being e antigen-positive showed loss of polymerase activity. An independent clinical evaluation showed a strong correlation between chronic hepatitis and positive reactions in the tests for e antigen and DNA polymerase. The results emphasize the possibility of differentiating between groups of chronic carriers of HBs Ag by testing for e antigen and Dane particle-associated DNA polymerase activity. The differentiation may have important clinical implications.
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PMID:Dane particle-associated DNA polymerase and e antigen: relation to chronic hepatitis among carriers of hepatitis B surface antigen. 93 24

Four patients with chronic hepatitis B infection and chronic active hepatitis were treated with human leukocyte interferon. Three of them had consistently elevated levels of circulating Dane-particle markers, including Dane-particle-associated DNA polymerase activity, hepatitis B core antigen and Dane-particle-associated DNA. Parenteral interferon administration at a dosage between 6.0 X 10(3) and 17 X 10(4) U per kilogram per day was associated with a rapid and reproducible fall in all Dane-particle markers in the three patients. The suppressive effect was transient when the interferon was given for 10 days or less but appeared to be more permanent when administration was prolonged for a month or more. In addition, long-term interferon therapy was associated with a marked fall in hepatitis B surface antigen in two of three patients and a disappearance of e antigen in two of two patients. Interferon may be useful in limiting carrier infectivity or eradicating chronic infection.
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PMID:Effect of human leukocyte interferon on hepatitis B virus infection in patients with chronic active hepatitis. 95 Sep 57

Sera from patients with acute hepatitis, cirrhosis or chronic hepatitis, as well as sera from healthy carriers and controls were examined for HBS antigen, DNA polymerase activity and for antibodies to HBS, HBC and DNA polymerase. The data presented suggest that in acute hepatitis the DNA polymerase test enabled us to diagnose at least 20% more cases of hepatitis B than with the RIA but that the DNA polymerase test is of little value for the screening of blood donors since all the healthy carriers gave negative results. As concerns the antibodies to DNA polymerase they appeared in at least 50% of the patients with acute hepatitis, they were transient and only detectable at the early beginning of the disease. These antibodies were also found to be different from the anti-HBS and anti-HBC antibodies.
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PMID:Transient antibodies to DNA polymerase in acute hepatitis B and related diseases. 96 84

Serum samples of 403 asymptomatic blood donors carrying hepatitis B surface antigen (HB5Ag) were concentrated threefold and tested for e antigen and antibody to e antigen (anti-e) by immunodiffusion. Hepatitis B antigen (HBAg)-associated deoxyribonucleic acid (DNA) polymerase activity was specifically determined by the difference in incorporation of [methyl-3H]thymidine 5' -triphosphate into DNA by an aliquot of centrifuged serum samples after it had been treated either with normal rabbit serum or with rabbit antibody to HBSAg. All of 58 serum samples containing e antigen revealed HBAg-associated DNA polymerase activity, whereas none of 96 samples containing anti-e did. In the remaining 249 samples in which neither e antigen nor anti-e was found, 62 showed specific DNA polymerase activity, although at lower levels than the samples containing e antigen.
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PMID:Hepatitis B antigen-associated deoxyribonucleic acid polymerase activity and e antigen/anti-e system. 96 88

To determine the relation between the presence of donor DNA polymerase and e antigen, and recipient hepatitis, we tested, under code, serums from a controlled trial of hepatitis B immune globulin used to treat individuals accidentally inoculated with HBs Ag-positive blood. All recipients lacked antibody to HBs Ag. In 29 of 31 donors, both polymerase and e were in perfect agreement; both demonstrated a highly significant correlation with recipient hepatitis (P less than 0.001). DNA polymerase/e-negative blood did not cause hepatitis. Blood containing polymerase or e antigen did not cause hepatitis in six of 31 and four of 18 recipients, respectively. Hepatitis did not correlate with transaminase or duration of antigenemia in the donor. Polymerase and e appear to be indicators of the relative infectivity of HBs Ag-positive serum, particularly after small-volume exposure. They may be important determinants in assessing infectivity of chronic carriers of HBs Ag and in evaluating efficacy of hepatitis B immune globulin and hepatitis B vaccines.
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PMID:Type B hepatitis: the infectivity of blood positive for e antigen and DNA polymerase after accidental needlestick exposure. 96


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