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)

To determine whether natural human interferon administered under the usual therapeutic dosing scheme would inhibit the hepatic drug metabolism, we performed an antipyrine test in eight patients with chronic B or non-A, non-B hepatitis before and after a subchronic interferon therapy (6 megaunits/day for 17 +/- 4 days, mean +/- SD). Six patients received interferon-beta and 2 received interferon-alpha. To circumvent a possible influence of interferon-induced fever on the hepatic drug metabolism, the antipyrine test during the interferon therapy was performed at least 14 days after the interferon-induced fever disappeared. The kinetic parameters of antipyrine were obtained from seven saliva samples over 32 hours postdose. There were no significant differences in any kinetic parameters of antipyrine observed before and during the interferon therapy. With the sample size of the study, there was only a 20% chance (i.e., beta-power = 0.8 at alpha = 0.05) that we might have missed a 17% reduction in antipyrine clearance by the interferon therapy (type II error). On the other hand, the subchronic interferon therapy lowered serum aminotransferases and DNA polymerase activity significantly (P less than .05) compared with the respective baseline values. Our results suggest that the subchronic therapeutic dosing scheme of interferon as conducted in the present study does not cause the inhibitory effect on the oxidative drug metabolism to a statistically significant or clinically relevant degree in patients with chronic hepatitis, while it improves their liver function. Further studies are required for determining if different types of interferons administered under the different dosing schemes would alter the hepatic drug metabolism and the inhibitory effect would be time-dependent.
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PMID:Effects of subchronic treatment with natural human interferons on antipyrine clearance and liver function in patients with chronic hepatitis. 211 64

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

Anti-idiotypic antibodies (anti-Id) against anti-HBs were found in the sera of patients with chronic hepatitis type B. Anti-idiotypic antibodies were detected by an enzyme-linked immunosorbent assay using horseradish peroxidase conjugated mouse monoclonal anti-HBs. Ten of 72 HBsAg positive sera contained anti-Id (13.9%). The prevalence of anti-Id did not appear to correlate with HBeAg/anti-HBe system. However, HB virus specific DNA polymerase activity was significantly higher in anti-Id positive sera. In the sera obtained from the patients treated with predonisolone before, anti-Id positive rate was higher than that in the patients without a history of predonisolone therapy. These results suggest that anti-Id may be related to the immunoregulatory mechanism of HB virus replication.
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PMID:Anti-idiotypic antibodies directed against anti-HBs among the patients with chronic hepatitis B. 225

Sera from four patients with acute hepatitis B and 87 patients with chronic hepatitis B were examined quantitatively for pre-S1 and pre-S2 antigens by solid-phase enzyme immunoassays. Pre-S1 and pre-S2 antigens were detected in HBsAg-positive sera irrespective of the presence of viral replicative markers, and their titers correlated with those of HBsAg (r = 0.74, p less than 0.01; r = 0.74, p less than 0.01, respectively). Sera positive for HBeAg showed higher titers of pre-S1 (p less than 0.01) and pre-S2 (p less than 0.01) antigens than sera negative for HBeAg. The titers of pre-S1 and pre-S2 antigens also correlated with the levels of HBV-associated DNA polymerase activity (r = 0.51, p less than 0.01; r = 0.59, p less than 0.01, respectively) and HBV-DNA (r = 0.50, p less than 0.01; r = 0.46, p less than 0.01, respectively). However, the ratios between the titers of pre-S antigens and HBsAg had no significant relationships with those viral replicative markers. These findings suggest that the expression of pre-S antigens is intimately related to the expression of HBsAg and that they are not useful as markers of viral replication. The ratios between the titers of pre-S antigens and HBsAg tended to be high in patients with chronic active hepatitis and high aminotransferase levels. This finding may have been due to the hepatic release of pre-S antigens, over-production of which may have some relationship to liver injury.
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PMID:Quantitative analysis of pre-S1 and pre-S2 in relation to HBsAg expression. 229 69

Sera from 20 Chinese patients with chronic hepatitis B were examined for hepatitis B e antigen and hepatitis B virus (HBV) DNA. There was considerable discordance with HBV DNA not being detectable in 10 out of 13 (77%) patients who were hepatitis B e antigen positive. Further testing for anti-HBe and HBV-DNA polymerase activity confirmed the results. Possible reasons for this discordance are discussed but neither hepatitis D (delta) infection nor the acquired immunodeficiency syndrome (AIDS) could be implicated.
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PMID:The absence of hepatitis B virus DNA in hepatitis B e antigen positive sera from chronic hepatitis B surface antigen carriers in China. 231 71

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 further clarify whether hepatitis B virus is cytopathic, the degree of hepatic histological activity was assessed and compared with levels of replicating virus in serum and liver of 74 untreated patients with chronic hepatitis B. Male homosexuals (n = 35) had significantly greater levels of DNA polymerase (P less than 0.05) and a trend toward higher hepatitis B virus DNA levels than heterosexuals (n = 39). Significantly greater DNA polymerase and hepatitis B virus DNA levels were observed in homosexuals infected with human immunodeficiency virus than in heterosexuals (P less than 0.005 and P less than 0.01, respectively) or human immunodeficiency virus-negative homosexuals (P less than 0.03 for both). Moreover, a trend was observed for higher grades of hepatitis B core antigen staining in the human immunodeficiency virus-infected population than in the human immunodeficiency virus-negative cohort. Hepatitis B virus DNA and DNA polymerase levels in the 74 patients were inversely related to total histological scores, and the degree of portal infiltrate and periportal necrosis bore an inverse relationship to peripheral markers of viral replication in human immunodeficiency virus-negative homosexuals and heterosexuals. Taken together, the data support the view that hepatitis B virus is not cytopathic because the amount of replicating virus does not directly correlate with the degree of histological activity.
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PMID:Relationship between histology, aminotransferase levels, and viral replication in chronic hepatitis B. 236 97

Twenty patients with hepatitis B e antigen (HBeAg) -positive chronic hepatitis, who received 40 mg of prednisolone per day for three weeks followed by withdrawal, were studied for changes in alanine aminotransferase (ALT), triiodothyronine (T3), thyroxine (T4), and hepatitis B virus DNA polymerase (HBV-DNAp) levels determined before and during prednisolone treatment and after its withdrawal. A decreased HBV-DNAp level of less than 100 cpm/ml three to five weeks after withdrawal was considered a sign of efficacy and was shown in 10 patients (50%). Significant differences were found between ALT levels, between T3 levels, and between the T3/T4 ratios assayed in the third and fourth weeks in total (P less than 0.02) and in the group in which efficacy was demonstrated (P less than 0.01). The T3/T4 ratio in the third week in the effectively treated group was significantly less than that in the noneffectively treated group (P less than 0.05). Prednisolone withdrawal effective for HBV-DNAp was shown in the patients with a decreased T3 level and the T3/T4 ratio at the third week and an increase in the ATL level after the withdrawal. The ALT level increased after the T3 level decreased. Changes in the T3 level or the T3/T4 ratio represent a marker for effectiveness of prednisolone withdrawal and for determination of combination therapy after steroid withdrawal.
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PMID:Triiodothyronine level and triiodothyronine/thyroxine ratio in HBeAg-positive chronic hepatitis patients treated with prednisolone withdrawal. 239 Sep 25

We have studied antibodies (anti-pol antibody) against the polymerase gene product of hepatitis B virus by solid-phase enzyme immunoassay using synthetic peptides coded for by this gene. Sera from six patients with acute hepatitis B, 112 chronic hepatitis B virus carriers and six healthy individuals with naturally acquired immunity to hepatitis B virus were tested for anti-pol antibody. In acute hepatitis B virus infection, anti-pol antibody was detected in three of six patients. In chronic hepatitis B virus infection, anti-pol antibody was detected in 17 of 29 (59%), in 23 of 33 (70%) of cirrhotic patients and in 18 of 24 (75%) patients with cirrhosis complicated by hepatocellular carcinoma, compared with 4 of 19 (21%) asymptomatic carriers and 2 of 7 (29%) patients with chronic persistent hepatitis. Titers of anti-pol antibody were higher in cirrhotic patients with and without hepatocellular carcinoma than in patients with chronic active hepatitis. The presence of anti-pol antibody, however, had no relationship with hepatitis B virus-associated DNA polymerase activities and other viral replicative markers. As for sera from six healthy individuals with naturally acquired immunity to hepatitis B virus, two (33%) were positive for anti-pol antibody. These results indicate that the immune response toward the polymerase gene product is induced during acute and chronic hepatitis B virus infection. In chronic hepatitis B virus infection, anti-pol antibody may serve as a new marker indicative of a long period of hepatitis B virus-induced hepatitis.
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PMID:Detection of antibodies against the polymerase gene product in hepatitis B virus infection. 239 Oct 62


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