Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The objective of this study was to find predictive factors of lopinavir/ritonavir (LPV/r) discontinuation for drug-related toxicities in highly pre-treated human immunodeficiency virus (HIV)-infected subjects. The study was an observational study of HIV patients starting LPV/r with HIV RNA > 3log10 copies/mL and a follow-up > or = 6 months. Parameters studied were HIV RNA, CD4+ cell counts, metabolic parameters and drug-related adverse events. Acquired immune deficiency syndrome (AIDS) events and deaths were recorded. The Kaplan-Meier (KM) model was used to estimate time-dependent probability, and the multivariable Cox model to identify predictors of LPV/r discontinuation for adverse events. The study evaluated 416 HIV-infected patients. Seventy-seven patients (18.5%) discontinued LPV/r for toxicities. Adverse events leading to LPV/r discontinuation were gastrointestinal symptoms in 40 cases, hyperlipidaemia in 27 and increase of aspartate aminotransferase (AST)/alanine aminotransferase (ALT) in 10 patients. Nineteen patients (4.6%) developed an AIDS event during observation and 15 (3.6%) died. The KM probability of LPV/r discontinuation for toxicities was 5.3% (range 3.1-7.5%) at month 12 and 15.7% (range 12.1-19.3%) at month 24. Subjects with hepatitis C virus (HCV)-HIV co-infection (odds ratio (OR) 7.40; 95% confidence interval (CI) 3.73-14.66 versus HCV-negative; P = 0.001) and receiving LPV/r plus nucleoside reverse transcriptase inhibitors (NRTIs) and protease inhibitor (PI)/non-nucleoside reverse transcriptase inhibitor (NNRTI) (OR 1.74; 95% CI 1.04-2.91 versus LPV/r plus only NRTIs; P = 0.04) showed a higher risk of LPV/r discontinuation by a Cox analysis, whereas non-intravenous drug abusers (IVDUs) (OR 0.40; 95% CI 0.24-0.67 versus IVDUs; P = 0.001) had a lower risk. The rate of discontinuation for toxicity decreased by 17% for each additional month of LPV/r exposure (OR 0.83; 95% CI 0.80-0.86 for each additional month; P < 0.001). LPV/r was substantially well tolerated. Diarrhoea was the most frequent adverse event leading to discontinuation. HCV-HIV co-infected patients and patients with a short exposure to LPV/r have a higher risk of discontinuing LPV/r and should be strictly monitored.
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PMID:Predictive factors of lopinavir/ritonavir discontinuation for drug-related toxicity: results from a cohort of 416 multi-experienced HIV-infected individuals. 1587 62

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

Liver enzyme elevations are frequently seen in patients treated with nevirapine (NVP). Both elevated NVP plasma levels and hepatitis C virus (HCV) infection seem to favor the development of NVP-related liver toxicity. We have examined variation on NVP C(trough) over time, as well as the impact of NVP C(trough) concentrations and the role of chronic hepatitis C on the incidence of liver enzyme elevations over a 48-week study period in HIV-infected patients on NVP therapy. Thirty-seven patients who initiated a triple regimen of NVP (200 mg bid) plus two nucleoside reverse transcriptase inhibitors (NRTI) were analyzed. A significant increase in serum transaminase levels occurred progressively over time. However, no significant variations in NVP plasma C(trough) were noticed in 48 weeks. In total population, maximum fold increase (MFI) in serum AST, ALT, and GGT was correlated with 24 week NVP C(trough). In HCV+ subjects, 12-week NVP C(trough) was closely correlated with maximum transaminase elevations, whereas in HCV- patients, 24-week concentrations were correlated with maximum transaminase increase. However, no differences in either NVP plasma C(trough) or in MFI in transaminase levels could be determined when comparing patients with and without hepatitis C at any time point.
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PMID:Changes in nevirapine plasma concentrations over time and its relationship with liver enzyme elevations. 1598 60

In the Asia Pacific region Human Immunodeficiency virus (HIV) is often acquired in individuals already infected with hepatitis B virus (HBV). The immune suppression caused by HIV infection reduces cellular immune response against HBV and liver inflammation may improve, but the risk of developing cirrhosis is not. HBV infection does not affect the progression of HIV disease. Anti-retroviral agents may be directly hepatotoxic and cause ALT elevations in patients with chronic hepatitis. Highly active anti-retroviral therapy (HAART) improves immunity and as cytotoxic lymphocyte responses improve, hepatitis flares can occur, usually r within 3 months of initiation of HAART. These hepatitis flares may be followed by normalization of ALT and clearance of HBVDNA. If lamivudine is included in the HAART regime, hepatitis flares may not occur till late and these late flares signal the development of lamivudine resistant HBV strains (90% of HBV/HIV co-infection). Treatment options for chronic HBV infection include interferon (IFN), and nucleoside analogues. Lamivudine, adefovir dipivoxil, tenofovir disoproxil fumarate (DF) are nucleoside analogues with activity against both HBVDNA polymerase and HIV reverse transcriptase. The latter two compounds have added activity against lamivudine resistant HBVDNA. Lamivudine should be avoided in the initial treatment of both hepatitis B as well as HIV because of the high incidence of resistance. Interferon should be considered first for treatment of HBV in HIV co-infected individuals and is usually unsuccessful in the later stages of HIV infection when immune suppression is extreme. As new and improved agents in HAART continue to prolong survival, the use of liver transplantation for cirrhotic patients co-infected with HIV and HBV may increase.
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PMID:Treatment of chronic hepatitis B in HIV co-infected patients. 1610 74

In vivo studies have shown that chronic alcohol consumption sensitizes the liver to endotoxemic shock, leading to liver microcirculation disruption. In the present study, we investigated the molecular mechanisms involved, focusing on endothelial nitric oxide synthase (eNOS) activity and regulation, which represents one of the major vasodilatory pathways. Male Sprague-Dawley rats were fed an alcohol liquid diet or a control isocaloric diet for 5 weeks. Priming effects of ethanol were studied in a model with or without a 24-h LPS treatment (1 mg/kg body weight). At the end of the diet, liver tissue was harvested for western blot, reverse transcriptase-PCR, histological analysis, and immunostaining and blood for serum alanine aminotransferase analysis. Chronic ethanol and LPS alone induced a mild hepatitis and infiltration, respectively. Combined, LPS and chronic ethanol feeding showed a synergistic effect on the liver, leading to extensive steatohepatitis with extensive focal necrosis associated with significantly higher levels of serum ALT. Chronic ethanol and LPS significantly inhibited eNOS activity, but exerted their effects through different mechanisms. Caveolin-1, an eNOS inhibitory protein, was upregulated after LPS and chronic alcohol consumption. Additionally, chronic alcohol consumption down-regulated endothelin B receptor, eNOS protein levels, and eNOS phosphorylation. In conclusion, chronic ethanol consumption and LPS share a similar pathophysiology and both lead to the impairment of eNOS activity, but through distinct molecular mechanisms. The presence of focal necrosis in a mild stress model could provide a good animal study to investigate the advanced stages of alcoholic liver diseases.
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PMID:Chronic ethanol sensitizes the liver to endotoxin via effects on endothelial nitric oxide synthase regulation. 1624 31

Patients who develop YMDD mutant during lamivudine therapy for hepatitis B virus (HBV) infection exhibit various clinical courses. Some patients show normal ALT levels, whereas others develop severe hepatitis exacerbations (SHEs) due to YMDD mutants. We studied 136 patients with YMDD mutant among 362 Japanese adult patients on lamivudine therapy. Clinical and virological features of patients without elevated HBV DNA after emergence of YMDD mutant (non-elevated group) were investigated. Moreover, virological analysis was also performed in patients with SHE due to YMDD mutants. Patients in the non-elevated group were characterized by HBeAg-negative pretreatment, HBeAg loss during therapy, a longer duration from commencement of therapy until emergence of YMDD mutant, and no mixed-type YMDD mutants. Patients with SHE had more substitutions in the reverse transcriptase (rt) region within the polymerase gene at the time of exacerbation than those without SHE, although no specific substitutions were noted. Sequence analysis of full-length HBV genome showed more substitutions in X, rt, and surface proteins in patients with SHE than in those without elevated HBV DNA level. In conclusion, negativity for HBeAg at commencement of therapy or before emergence of YMDD mutant was an important factor among non-elevated group. More substitutions in the rt region and the other proteins may be related to the emergence of severe hepatitis caused by lamivudine-resistant virus.
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PMID:Clinical and virological features of non-breakthrough and severe exacerbation due to lamivudine-resistant hepatitis B virus mutants. 1641 16

Lamivudine and adefovir have potent inhibitory effects on hepatitis B virus (HBV) replication. Although short-term therapy is feasible in a selected subgroup of patients, prolonged therapy is required for sustained suppression in the majority of patients. However, HBV species with mutations in the tyrosine-methionine-aspartate-aspartate (YMDD) locus of the HBV RNA-dependent DNA polymerase (rtM204 I/V) conferring resistance to lamivudine may emerge after 9-10 months therapy. The incidence increases with duration of therapy up to 70% after 5 years lamivudine therapy. Serum alanine aminotransferase (ALT) elevation and HBV DNA rebound ( I log) occur in >90% of the patients with rtM204 I/V during continued lamivudine therapy. Marked flare of serum ALT may occur, sometimes severe, and may be complicated with decompensation or even fatality. The initial clinical and histologic improvement may also reverse after emergence of rtM204 IN Studies do suggest that stopping seems better than continuing lamivudine therapy. Limited data show that interferon therapy seems ineffective. Add-on adefovir therapy is effective in suppressing rtM204 I/V in both compensated and decompensated patients. Switching to adefovir monotherapy is effective and safe even in cirrhotic patients with decompensation. The overall incidence of adefovirresistant rtN236T and A181V is low, being 0 after one year and 5.9% after 3 years' therapy. The impact of adefovir resistance is less clear but is responsive to lamivudine therapy. In conclusion, monitoring of viral breakthrough to start effective intervention is mandatory during direct antiviral therapy.
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PMID:The current management of HBV drug resistance. 1646 Dec 16

Chronic hepatitis B is a common disease and approximately 20% of infected patients with compensated cirrhosis will decompensate over 5 years. If untreated, the survival of decompensated cirrhosis is poor (15% at 5 years). The extent of hepatitis B virus (HBV) replication, as assessed by serum HBV-DNA level, is a strong predictor of the risk of disease progression and hepatocellular carcinoma. This provides a rationale for antiviral therapy to arrest progression of liver disease. Lamivudine is a pyrimidine analogue that inhibits HBV-DNA reverse transcriptase. It decreases HBV replication, normalises alanine aminotransferase levels and reduces hepatic inflammation and fibrosis in patients with chronic hepatitis B. This article will focus on the use of lamivudine in patients with HBV-cirrhosis. In patients with compensated HBV-cirrhosis, a randomised, placebo-controlled trial has shown that lamivudine significantly reduced the rate of disease progression and hepatocellular carcinoma development over a 3-year period. In patients with decompensated cirrhosis, treatment with lamivudine can produce spectacular improvements of liver function, but the improvement is slow and a clinical benefit is usually not observed until after at least 3-6 months of treatment. A major drawback of lamivudine treatment is the development of resistance, observed in 15-20% of patients after 1 year and up to 70% after 5 years of continued treatment. Thus, patients with HBV-cirrhosis treated with lamivudine should have regular monitoring of serum HBV-DNA levels and prompt institution of additional antiviral therapy if viral breakthrough is observed. Adefovir, tenofovir and entecavir have demonstrated efficacy in patients with lamivudine resistance. In patients with decompensated cirrhosis, in whom the development of resistance can be fatal, combination therapy (such as lamivudine plus adefovir) may prove more effective than monotherapy and this issue needs further study.
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PMID:Lamivudine treatment in patients with chronic hepatitis B and cirrhosis. 1692 9

Ginkgo biloba extract has been shown to be hepatoprotective. However, its benefits when used in alcoholic liver injury have not been demonstrated. This study investigated the effects of Ginkgo biloba extract on alcohol-induced liver injury in a chronic alcohol plus fish oil gavage model in rats. Liver injury was evaluated histologically and by serum alanine aminotransferase (ALT). Liver tumor necrosis factor-alpha (TNF-alpha) protein levels, malondialdehyde (MDA) and glutathione (GSH) contents were determined. TNF-alpha mRNA expression in the liver was analysed by reverse transcriptase-polymerase chain reaction (RT-PCR). Rats given fish oil plus alcohol developed macrovesicular and microvesicular steatosis, spotty necrosis and mild inflammation in the liver and elevated serum ALT levels, which were accompanied by increased MDA contents, reduced GSH contents and elevated TNF-alpha protein and mRNA expressions in the liver. Supplementation with Ginkgo biloba extract (200 mg/kg, orally) improved the liver injury, blunted the rises of MDA contents and TNF-alpha expression, and restored the GSH content in the liver. Ginkgo biloba extract protects against alcohol-induced liver injury, and the mechanism may involve a reduction of lipid peroxidation, prevention of GSH depletion and inhibition of TNF-alpha expression in the liver.
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PMID:Ginkgo biloba extract protects against alcohol-induced liver injury in rats. 1715 34

Although hepatitis B virus (HBV) RNA splicing has been reported by many researchers, the clinical significance of this event remains illusive. The present study was designed to investigate the clinical roles of singly spliced HBV-RNA. Liver biopsy tissues obtained from 32 consecutive patients were subjected to reverse transcriptase-polymerase chain reaction for the detection of singly spliced and unspliced HBV-RNA. Stepwise linear regression model was used to estimate the ratio of singly spliced to unspliced (S/US) HBV-RNA in the presence of the following variables: age, gender, aspartate aminotransferase, alanine aminotransferase, total bilirubin, alpha-foetoprotein, status of HBV e antigen (HBeAg), status of antibody to HBeAg, HBV-DNA, histology activity index (HAI), fibrotic score, grade of cytoplasmic HBV core antigen (HBcAg), grade of nuclear HBcAg, genotype, status of precore-stop-mutation, basal core promoter mutation, previous lamivudine therapy and superinfection by other hepatitis viruses. The results showed that HAI (beta = -0.2616; P = 0.011) and grade of nuclear HBcAg expression (beta = 0.5599; P =0.0067) were two independent predictors for the expression of singly spliced HBV-RNA. Further categorical analysis showed that patients with HAI score <or=6 and grading of nuclear HBcAg >or=2 have significantly higher S/US ratios. In conclusion, nuclear HBcAg and HAI are two independent predictors for the expression of singly spliced HBV-RNA.
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PMID:Nuclear HBcAg and histology activity index as independent predictors of the expression of singly spliced HBV-RNA. 1721 47


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