Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Among 262 inpatients with hematologic diseases who were referred for chemotherapy or immunosuppressive therapy between January, 1985, and December, 1989, nine (3.4%) patients, including two with Hodgkin's disease (HD), three with acute myeloblastic leukemia, one with chronic myelogenous leukemia, two with multiple myeloma and one with aplastic anemia, were found to be hepatitis B virus (HBV) carriers before their chemotherapy began. All six HBV carriers who received chemotherapy containing glucocorticoid showed mild-to-moderate elevations in serum transaminase levels after the chemotherapy. Five showed a rise in titer of the hepatitis B surface antigen, HBsAg. In contrast, three HBV carriers not receiving glucocorticoid showed no change in serum transaminase after chemotherapy. One HBV carrier with HD suffered from severe icteric hepatitis after the withdrawal of multiagent chemotherapy containing glucocorticoid. The HBV-DNA polymerase rose markedly and was accompanied by a marked rise in titer of HBsAg. The results warn us to keep in mind the possibility of glucocorticoid inducing an activation of HBV infection, which may result in severe hepatitis in some HBV carriers. Although further investigation is required, it is recommended that HBsAg-positive patients with hematologic malignancies should, if possible, be treated without glucocorticoid.
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PMID:Activation of hepatitis B virus infection by chemotherapy containing glucocorticoid in hepatitis B virus carriers with hematologic malignancies. 175 16

Seventeen patients with chronic hepatitis B were treated with a 4-week administration of glycyrrhizin followed by a 4-week treatment with human lymphoblastoid interferon, then followed for 6 months after the end of treatment. All were positive for hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), and hepatitis B virus-associated DNA polymerase (DNA-p) for at least 6 months before entry. All patients were Japanese and none of them were homosexuals. Eleven patients lost DNA-p activity and 10 of them lost HBeAg. Three of these 10 patients had antibody to HBeAg. In 10 patients who became HBeAg-negative, alanine aminotransferase levels after glycyrrhizin administration were higher and initial DNA-p activities relatively lower than the levels found in seven patients who remained HBeAg-positive. The immunomodulator provided by a short course of glycyrrhizin before administration of human lymphoblastoid interferon may be an effective treatment for patients with chronic hepatitis B.
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PMID:Glycyrrhizin withdrawal followed by human lymphoblastoid interferon in the treatment of chronic hepatitis B. 176 47

Twenty-one adult patients with chronic hepatitis B and active viral replication as indicated by positivity for hepatitis B e antigen and hepatitis B virus DNA, with increased DNA polymerase levels for more than 6 months, were entered into a prospective trial of low-dose recombinant human alpha-interferon therapy. All patients were treated with 5 million units of recombinant interferon alfa-2b given subcutaneously every other day for 12 weeks. During treatment, 18 patients (86%) showed a significant reduction of DNA polymerase levels (p less than or equal to 0.001), which reached normal values in ten (48%). After 10 months' mean follow up, seven patients (33%) were hepatitis B e antigen negative and five (24%) subsequently became positive for antibodies to e antigen. By 27 months, nine patients (43%) were both hepatitis B e antigen negative and e antibody positive. Only one patient became permanently negative for hepatitis B surface antigen. One patient relapsed during the second year of follow up. Side effects necessitated withdrawal of therapy in two patients: one due to worsening thrombocytopenia after two doses of interferon (data omitted from the study results) and one due to a local reaction at the injection sites. Our data indicate that small doses of recombinant interferon alfa-2b given during a 12-week period induce a significant reduction in viral replication and approximately triple the spontaneous seroconversion rate observed in patients with chronic hepatitis B.
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PMID:Prospective trial of recombinant leucocyte interferon in chronic hepatitis B: a long-term follow-up study. 207 69

Serum DNA polymerase activity (DNA-P) was detected in 27.6 per cent of non-A, non-B (NANB) hepatitis patients, 8.7 per cent of patients with alcoholic liver disease (ALD), 8.6 per cent of hepatitis B surface antigen (HBsAg)-positive patients and 19.0 per cent of HBsAg-negative blood donors with elevated serum glutamic-pyruvic transaminase (SGPT) concentrations. In contrast, none of the patients with hepatitis A, drug-induced liver injury or non-alcoholic fatty liver had DNA-P in their sera in the acute phase of the illness. All HBsAg-positive samples with detectable DNA-P were strongly positive for hepatitis B virus (HBV) DNA, but the samples from patients with NANB hepatitis and ALD and HBsAg-negative blood donors had no HBV DNA. Sensitivity to actinomycin D showed the heterogeneity of DNA-Ps in HBsAg-negative blood donors; the enzyme activity of one type was inhibited by 100 micrograms/ml of actinomycin D, whereas the other was not. The preference for exogenous template primers of these DNA-Ps was different to those of HBV and human retroviruses. The results reveal the prevalence of serum DNA-P in NANB hepatitis patients and suggest that two distinct agents are relevant to the aetiology of NANB hepatitis.
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PMID:Prevalence and heterogeneity of serum DNA polymerase activity in patients with non-A, non-B hepatitis and HBsAg-negative blood donors with elevated SGPT. 212 73

An in vitro system for production of hepatitis B virus (HBV) was established by infection of human hepatoma (HepG2) cells. HBV particles obtained from the serum of a chronic hepatitis B surface antigen (subtype ad) carrier were used to inoculate HepG2 cells. HBV envelope and core proteins were synthesized de novo by the infected cells and secreted into the medium 3 to 6 days postinfection. Viral covalently closed circular DNA, the putative template for viral RNA transcription, accumulated in the cells with increasing time postinfection. The HBV-infected HepG2 cells were maintained for several months (HepG2-BV cell line) and continued producing viral antigens. Both HBV DNA replicative intermediates and major HBV transcripts were identified in HepG2-BV cells. Complete HBV particles, which contain HBV DNA and DNA polymerase activity and express the three antigenic specificities of the envelope (hepatitis B surface antigen, pre-S2, and pre-S1), were released into the culture supernatant. Thus, successful in vitro infection of transformed human hepatocytes raising stable HBV-producing cells was achieved for the first time. This strongly suggests that HepG2 cells have a receptor(s) for virus attachment and penetration. Such a system represents a significant advance for the study of HBV-target cell interactions as the early events of HBV infection.
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PMID:In vitro infection of human hepatoma (HepG2) cells with hepatitis B virus. 215 60

Since 1965, when Blumberg discovered the Australia antigen, the hepatitis B surface antigen (HBsAg), the research on viral hepatitis has rapidly progressed. The identification of specific hepatitis B associated antigens and antibodies in blood, and liver tissue, together with the improvement of detection systems, have enhanced our knowledge about the mechanism of liver injury and the natural history of hepatitis B virus (HBV) infection. Now it has been recognized that HBV has no direct cytopathic effect on hepatocytes and that hepatocyte necrosis is associated with the virus induced immunological reaction of the host. From the reaction, there are two types of HBV infection, i.e., transient (acute) and persistent (chronic) infection. In addition to the conventional measurements, such as HBsAg, anti-HBs, anti-HBc, HBeAg, anti-HBe and anti-IgM HBc, recently pre S1, pre S2 antigen/antibody systems and polymerized human albumin receptor and antibody have been developed. The significance of the detection of these antigen/antibody systems was discussed. On the other hand, to determine the presence of HBV, the state of HBV replication or the infectivity directly, HBV associated DNA polymerase and HBVDNA should have been detected. (Very recently, the polymerase chain reaction method has been introduced to detect very small amounts of HBVDNA). In this presentation, the change of these viral markers in various cases was shown, and especially emphasized was anti-IgM HBc in acute hepatitis and HBeAg/Ab status in chronic liver disease. Lastly, the present state of Interferon therapy for type B chronic hepatitis was mentioned.
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PMID:[Diagnosis of type B hepatitis]. 219 6

Hepatitis B virus genome-transfected HepG2 cells (2.2.15 cells) inoculated into nude mice produced tumors within 2-8 wk. Dane particles, hepatitis B virus deoxyribonucleic acid polymerase activity, hepatitis B surface antigen, and hepatitis B e antigen were detected in the serum, and 36% of mice developed antibodies to hepatitis B core antigen. In the tumors, hepatitis B surface, core, and e antigens were observed by electron microscopy and immunoenzymatic techniques. In-situ hybridization and Southern blot analysis showed hepatitis B virus deoxyribonucleic acid in the tumor. Tumors could be propagated by injection of minced tumor tissue or of a tumor-derived cell line. Liver of tumor-bearing mice as well as sera and tissues of mice inoculated with control cell lines did not show hepatitis B virus genome or viral markers. Tumors induced by both 2.2.15 and nontransfected HepG2 cells exhibited myc oncogene protein and various hepatoma-associated antigens (alpha-fetoprotein, alpha-1-antitrypsin, alpha-1-antichymotrypsin, carcinoembryonic antigen, cytokeratin), suggesting that viral formation does not interfere with expression of these antigens. This experimental model will be helpful to study the effect of drugs on in-vivo hepatitis B virus replication and viral antigen expression.
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PMID:A nude mouse model for the in vivo production of hepatitis B virus. 229 3

Twenty-six patients, positive for hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), hepatitis B virus (HBV)-deoxyribonucleic acid (DNA), and DNA polymerase activity, were treated with human lymphoblastoid interferon (IFN-alpha) or human fibroblast interferon (IFN-beta) after enoxolone glycoside (glycyrrhizinic acid), given for four weeks and then withdrawn. The interferons were given continuously for four weeks. Four months after the treatment, six of 12 patients treated with IFN-alpha were both HBeAg-negative and HBV-DNA-negative while three of 14 patients treated with IFN-beta were HBV-DNA-negative and one was HBeAg-negative. None of the ten untreated control patients became negative for either HBeAg or HBV-DNA. All patients studied remained HBsAg-positive. Both interferons were generally well tolerated. A persistent low-grade fever was reported by more patients in the IFN-beta group and hair and weight loss were more common in the IFN-alpha group. The results indicate that the combination of enoxolone glycoside withdrawal and IFN-alpha treatment reduces HBV replication more effectively than does interferon alone.
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PMID:Human lymphoblastoid and fibroblast interferon in the treatment of chronic hepatitis B. 232 24

Because the risk factors for human immunodeficiency virus (HIV) infection and hepatitis B (HBV) are similar and therefore coinfection is not uncommon, a detailed histological and immunohistochemical study of chronic hepatitis B infection in a group of 20 HIV positive Caucasian males (who did not have AIDS) and 30 HIV negative controls were undertaken. Using both the conventional histological classification and the Knodell histological activity index it was shown that HIV negative patients were more likely to have active disease and also more scarring than HIV positive patients. Hepatitis B surface antigen (HBsAg) expression was not significantly different between the two groups but expression of hepatitis Be antigen (HBeAg) and HBV-DNA polymerase was greater in those who were HIV positive. HIV positive patients are therefore more likely to have immunohistochemical markers of active viral replication, although histologically, liver disease is less severe. These findings have important implications for assessing the biopsy specimens in this group of patients and for treatment strategies aimed at improving their immune function.
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PMID:Histological and immunohistochemical study of hepatitis B virus in human immunodeficiency virus infection. 233 17

To identify factors predicting response to antiviral therapy, we reviewed the clinical features of 38 male hepatitis B surface antigen (HBsAg) carriers who received adenine arabinoside or lymphoblastoid interferon. All patients were followed for one year or longer. Response was defined as loss of hepatitis B e antigen, hepatitis B virus DNA and DNA polymerase from the serum. Only 2 of 19 (11%) homosexual men responded, compared with 10 of 19 (53%) heterosexual men (P less than 0.02). Both responders in the homosexual group had received lymphoblastoid interferon. None of the 13 homosexual men, but 8 of 16 heterosexual men, responded to adenine arabinoside or its monophosphate (P less than 0.01). Responders to antiviral therapy had higher (P less than 0.05) serum levels of aspartate aminotransferase (median 115, range 51-344) than did non-responders (median 83, range 32-181). The decreased responsiveness of homosexual men to antiviral therapy may be a result of more severe immunologic abnormalities in homosexual than in heterosexual men with HBsAg-positive chronic liver disease.
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PMID:Diminished responsiveness of homosexual men to antiviral therapy for HBsAg-positive chronic liver disease. 241 58


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