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)

Twenty patients with HBe antigen positive, chronic active hepatitis receiving interferon-beta (HuIFN-beta) for 4 weeks were studied. Within the follow-up period (12.3 +/- 2.0 months; mean +/- SD), nine patients were seroconverted to anti-HBe positive and/or HBe antigen negative. In vitro synthesis of interleukin-1 (IL-1), interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) were determined from supernatants of peripheral blood mononuclear cells (PBMCs) cultured in the presence of lipopolysaccharide or concanavalin-A. PBMCs from patients before IFN-beta treatment secreted markedly reduced levels of IL-1 (p less than 0.01) and IFN-gamma (p less than 0.01) as compared with healthy controls. However, IFN-gamma synthesis in the patients was significantly increased (p less than 0.05) along with the IFN-beta treatment. IL-2 synthesis was similar in chronic active hepatitis B patients before and during IFN-beta treatment when compared to normal controls, but after the therapy, the elevation of IL-2 synthesis was observed in accordance with the elevation of serum AST in two cases. Nine patients who seroconverted to anti-HBe positive and/or HBe antigen negative showed the significantly lower levels of DNA polymerase before IFN-beta treatment than non-responder group. There were no other differences in sex, age, serum AST, histologic activities and cytokine production in vitro between two groups. These results indicate the presence of immunologic deficiencies in patients with HBe antigen positive chronic active hepatitis and give the rationales for the use of interferon treatment on immunologic basis.
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PMID:[In vitro cytokine production in patients with HBe antigen positive chronic active hepatitis receiving interferon-beta]. 250 83

Interferon-alpha induces remission in 30% to 40% of patients with chronic hepatitis B, but its effect on hepatic connective tissue turnover has not been well documented. We studied the changes in serum procollagen III propeptide and laminin-P1 peptide (Lam-P1) in 33 patients with chronic hepatitis B (11 nontreated controls and 22 treated patients) during a 4-mo randomized trial of interferon-alpha. Liver biopsy specimens were obtained at the start of treatment and 12 mo later. Liver biochemical tests, procollagen III propeptide, laminin-P1 peptide and hepatitis B virus DNA polymerase were determined before treatment with interferon was begun (mo -3), at the initiation (0 time) and completion of treatment (mo 4) and also at 8, 12 and 18 mo. Treated patients were classified as "responders" and "nonresponders" on the basis of clearance of HBV e antigen from serum. There were no significant changes in the control group, whereas the responders had persistent decreases in ALT, AST, hepatitis B virus dna polymerase, procollagen III propeptide and laminin-P1 peptide. The nonresponders had transient ALT, AST and hepatitis B virus dna polymerase reductions that returned toward baseline levels during follow-up, but procollagen III propeptide and laminin-P1 peptide persisted below the baseline at mo 18. Significant correlations between procollagen III propeptide and laminin-P1 peptide with ALT, AST and liver histologic specimens were noted at baseline but not after 12 mo. Changes in procollagen III propeptide levels also correlated with changes in AST, ALT and liver histologic specimens.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Decrease in serum levels of markers of hepatic connective tissue turnover during and after treatment of chronic hepatitis B with interferon-alpha. 813 56

Interferon-alpha therapy leads to HBeAg seroconversion in only one third of patients with chronic hepatitis B. In an attempt to increase the seroconversion rate, we investigated the combination of interferon-alpha and zidovudine in a subset of patients with presumably low response rates for interferon-alpha monotherapy. In a double-blind, controlled trial, 24 HBeAg-positive patients were randomized to receive lymphoblastoid interferon-alpha in subcutaneous doses increasing to 5 MU daily, combined with zidovudine given orally in doses increasing from 500 to 1,000 mg/day or with placebo for 16 wk. Treatment effects were monitored by quantitative assessment of HBV DNA, HBeAg and HBV DNA polymerase. Six months after termination of therapy, 1 of 12 (8%; 95% confidence interval = 2% to 39%) patients treated with interferon-alpha plus zidovudine and 2 of 12 (17%; 95% confidence interval 2% to 48%) patients from the control group exhibited responses (HBeAg seroconversion). All patients remained HBsAg positive. The only responder of the interferon-alpha-zidovudine group relapsed after cessation of therapy, so none of the zidovudine-treated patients were HBeAg negative at the end of follow-up. No significant difference in AST level or in any of the virological markers was observed between the two groups during the course of the study. Adverse effects (anemia, leukopenia) necessitated reduction in the dose of zidovudine in 50% and of interferon-alpha in 42% of the patients treated with interferon-alpha plus zidovudine; in the control group these rates were 0% for placebo and 8% for interferon-alpha. In conclusion, the antiviral effect of interferon-alpha in chronic hepatitis B was not enhanced by additional zidovudine treatment. The combination therapy induced considerable side effects leading to dose reduction for both zidovudine and interferon-alpha. For combination therapy with interferon-alpha, oral nucleoside analogs with more potent antiviral effects and less toxicity than zidovudine should be developed.
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PMID:Interferon-alpha and zidovudine combination therapy for chronic hepatitis B: results of a randomized, placebo-controlled trial. 844 11

Patients who will receive chemotherapy require careful assessment of liver function prior to treatment to determine which drugs are not appropriate, and which drugs need dose modification. However, if the hepatic parenchymal abnormalities are caused by an underlying neoplasm and the neoplasm is sensitive to the drugs, it may not be necessary to reduce the dose. Clearly, this is an area where clinical judgment must be used to assess the risk/benefit ratio. Treatment of chronic hepatitis B virus (HBV) involves either the nucleoside analogue lamivudine or interferon alpha. The advantage of lamivudine includes limited adverse effects and the fact that histological improvement has been documented in the majority of patients. Primary prophylaxis with lamivudine may be a well tolerated and effective method to reduce the frequency of chemotherapy-induced HBV reactivation in chronic HbsAg carriers. HbsAg screening is necessary before beginning chemotherapy for non Hodgkin's lymphoma patients. However, the main problem with long-term lamivudine therapy is the emergence of genotypic resistance because of base pair substitution at specific sites within the YMDD locus of the DNA polymerase gene. Significant hepatic dysfunction is uncommon among hepatitis C virus (HCV) infected patients treated with chemotherapy for hematological malignancies. However, infection with elevated AST levels is a significant risk factor for veno-occlusive disease after hematopoietic stem cell transplantation. Clinical judgment and a high index of suspicion remain critical tools in preventing and treating hepatic manifestations of cancer chemotherapy.
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PMID:[Hepatotoxicity of chemotherapy]. 1285 43

Adefovir is classified as a nucleotide reverse transcriptase inhibitor because it acts by inhibiting hepatitis B virus DNA polymerase (reverse transcriptase) and causing DNA chain termination after its incorporation into the viral DNA. Adefovir dipivoxil is indicated for the treatment of chronic hepatitis B in adults with evidence of active viral replication and either evidence of persistent elevations in serum aminotransferases (alanine [ALT] or aspartate [AST]) or histologically active disease. It is useful in the treatment of patients with either hepatitis B e antigen-positive or -negative chronic hepatitis B. The recommended adefovir dipivoxil dose in the treatment of chronic hepatitis B in patients with adequate renal function is 10 mg once daily. Adefovir dipivoxil therapy can reduce viral load, improve ALT, and produce histologic improvement in patients with chronic hepatitis B. Improvements are generally seen within the first few weeks of therapy and have shown persistence up to at least 3 years with continued therapy. Therapy with adefovir dipivoxil is generally well tolerated. However, nephrotoxicity is a risk with adefovir therapy, especially in patients receiving higher doses (30-120 mg/d). Patients should have their renal function monitored closely throughout therapy and may require an adjustment in dose relative to changes in the creatinine clearance. Lactic acidosis and severe hepatomegaly with steatosis may also occur during therapy.
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PMID:Adefovir dipivoxil: focus on its use in the treatment of chronic hepatitis B. 1597 40