Mutations in the YMDD motif of the hepatitis B virus (HBV) DNA polymerase result in reduced susceptibility of HBV to inhibition by lamivudine, at a cost in replication fitness. The mechanisms underlying the effects of YMDD mutations on replication fitness were investigated using both a cell-based viral replication system and an in vitro enzyme assay to examine wild-type (wt) and YMDD-mutant pol...

 Abstract Background: Investigators were suspicious of tyrosine-methionine-aspartate-aspartate (YMDD) mutations occurred only in patients who were treated by lamivudine. However, YMDD mutations of hepatitis B virus gene (HBV DNA) in patients with chronic hepatitis B (CHB) untreated with antiviral medicines was reported in some studies. The aim of this study was to evaluate YMDD mutations in Ira...

abstract background: investigators were suspicious of tyrosine-methionine-aspartate-aspartate (ymdd) mutations occurred only in patients who were treated by lamivudine. however, ymdd mutations of hepatitis b virus gene (hbv dna) in patients with chronic hepatitis b (chb) untreated with antiviral medicines was reported in some studies. the aim of this study was to evaluate ymdd mutations in iran...

conclusions this study showed that the presence of mutation at codons rtl80v, rtl180m and rtm204v in a, b and c domains is associated with higher viral load and resistance to lamivudine (3tc) respectively. results about 6% (3 of 50) of samples were hbeag positive and 94% (47 of 50) of patients were hbeag negative by elisa method. the patients' alt level was between 16 and 95 iu/l with the mean ...

BACKGROUND Many determinants for a sustained response to lamivudine therapy have been reported but the role of T cell responsiveness remains unclear. The finding that tyrosine-methionine-aspartate-aspartate (YMDD) motif of the reverse transcriptase domain of hepatitis B virus (HBV) DNA polymerase carries a HLA-A2 restricted cytotoxic T lymphocyte (CTL) epitope makes quantitative measurement of ...

Lamivudine is a major drug approved for treatment of chronic hepatitis B virus (HBV) infection. Emergence of drug-resistant mutants with amino acid substitutions in the YMDD motif is a well-documented problem during long-term lamivudine therapy. Here we report a novel lamivudine-resistant strain of HBV with an intact YMDD motif, which included an amino acid substitution, rtA181T, in the reverse...

AIM To polymerase P region (YMDD) mutations of hepatitis B virus gene (HBV DNA) in patients with chronic hepatitis B (CHB) untreated with antiviral medicines and to explore its correlation with pre-c-zone mutations, HBV genotypes and HBV DNA level, and to observe its curative effect. METHODS A total of 104 cases (38 cases in group of familial aggregation and 66 cases in group of non-familial ...

The emergence of compensatory mutations in the polymerase gene of drug resistant hepatitis B virus (HBV) is associated with treatment failure. We previously identified a multi-drug resistant HBV mutant, which displayed resistance towards lamivudine (LMV), clevudine (CLV), and entecavir (ETV), along with a strong replication capacity. The aim of this study was to identify the previously unknown ...

A high incidence of HBV-related hepatitis is associated with the use of HBsAg-positive marrow for transplantation, and the high viral load in the donor appears to predispose recipients to the development of HBV-related hepatitis postransplant. Preemptive use of lamivudine has proved to reduce hepatitis B exacerbation in HBsAgpositive recipients of allogeneic HCT. Since 2000, the policy in our m...

The objective of this research was to determine the relationship between YMDD mutations and the genotypes of hepatitis B virus (HBV) during lamivudine treatment. HBV genotypes were determined by nested PCR with 6 pairs of HBV genotype-specific primers (A to F) in serum specimens from 142 hepatitis B patients receiving lamivudine antiviral therapy. YMDD mutations were detected by fluorescent hyb...