We previously developed a method of detecting drug-resistant mutation of hepatitis B virus (tyrosine (Y)-methionine (M)-aspartic acid (D)-aspartic acid (D) (YMDD) mutation) caused by the antiviral agent lamivudine. Using this method, we also reported that YMDD mutation is present in asymptomatic carriers that had not been administered antiviral agents. Thus, we investigated the clinical charact...

BACKGROUND We recently reported complex hepatitis B virus (HBV) drug resistant and concomitant vaccine escape hepatitis B surface antigen (HBsAg) variants during human immunodeficiency virus (HIV) co-infection and antiretroviral therapy (ART) exposure in Ethiopia. As a continuation of this report using the HBV positive sera from the same study participants, the current study further analyzed th...

AIM To look for a rapid low-cost technique for the detection of HBV variants. METHODS Two patients who underwent orthotopic liver transplantation (OLT) for HBV infection were treated with lamivudine (100 mg daily) and HBV infection recurred in the grafted livers. The patients were monitored intensively for liver enzymes, hepatitis B surface antigen (HBsAg) and HBV DNA in serum. Liver biopsy w...

YMDD variants of hepatitis B virus (HBV) emerge in some patients with chronic hepatitis B who receive lamivudine. YMDD variants were examined in 794 patients in 4 controlled studies of 1 year's duration. The long-term effects of YMDD variants were examined in a subset of patients treated up to 4 years. YMDD variants were detected by polymerase chain reaction (PCR) and restriction fragment-lengt...

AIM To develop a simple and rapid detection of HBV gene variants and prediction of lamivudine-resistance in patients. METHODS Initially, plasmids harboring the wild-type or mutant HBV DNA fragments were used in a model system. The technique was then applied to clinical samples for an analysis of YMDD mutations. The sera were extracted from chronic hepatitis patients who had received lamivudin...

BACKGROUND Several recent reports have demonstrated that tyrosine (Y)-methionine (M)-aspartic acid (D)-aspartic acid (D) (YMDD) motif mutations can naturally occur in chronic HBV patients without antiviral treatment such as lamivudine therapy. This paper aims to assess the overall spontaneous incidence and related risk factors of YMDD-motif mutations among lamivudine-naïve chronic HBV carriers,...

amivudine (LAM), a nucleoside analog, was the first anti-HBV rug approved for antiviral therapy in China. Long-term antivial therapy with LAM may lead to drug resistance, which is ssociated with a mutation in tyrosine-methionine-aspartic cid-aspartic acid (YMDD) motif of the reverse transcripase in HBV-DNA genome. Several previous studies showed hat YMDD mutations were also present in treatment...

BACKGROUND Lamivudine is used for the treatment of chronic hepatitis B patients. Recent studies show that the YMDD motif mutants (resistant hepatitis B virus) occur as natural genome variability in lamivudine-untreated chronic hepatitis B patients. In this study we aimed to determine the rate of YMDD motif mutants in lamivudine-untreated chronic hepatitis B patients in Iran. PATIENTS AND METH...

Oxymatrine (OMTR) is widely used for the treatment of chronic hepatitis B (CHB) in China. Several reports revealed that combination of OMTR and lamivudine reduced the incidence of tyrosine- (Y-) methionine- (M-) aspartic acid- (D-) aspartic acid (D) (YMDD) mutations in CHB patients. The aim of this study was to evaluate the clinical value of oxymatrine in preventing lamivudine induced YMDD muta...

BACKGROUND/AIMS To study the outcome and the virologic profiles of severe hepatitis exacerbations due to YMDD mutants in lamivudine-treated patients. METHODS Eighteen lamivudine-treated patients with severe hepatitis exacerbations due to YMDD mutants were recruited. Laboratory and clinical parameters were monitored. Viral genotypes and YMDD mutations were determined. RESULTS None of the 18 ...