| This study was composed of three parts: I . Detection of HBV YMDD motif mutation with direct sequencing of PCR products and its clinical application; II. A new method of genotyping hepatitis B virus on the basis of restriction fragment length polymorphism of polymerase chain reaction products of the viral pres/s gene; III. Evaluation of foscarnet sodium in the treatment of chronic hepatitis B.I . Detection of HBV YMDD Motif Mutation with Direct Sequencing of PCR Products and Its Clinical ApplicationObjective To increase the positive rate of polymerase chain reaction(PCR) in the detection of hepatitis B virus(HBV) P gene and to investigate the clinical implication of HBV YMDD motif mutation. Methods To reduce the blight of the mismatch between primers and the primer binding sites in template, some methods were applied such as choosing primers, amending primers, optimizing PCR condition, decreasing the anneal temperature, etc. The YMDD mutation was detected in sixteen patients with untreated chronic hepatitis B. The YI/VDD mutation were found in twenty-two patients treated with lamivudine, and liver functions and HBV DNA quantity were determined. Results The methods we developed significantly increased the positive rate of PCR in the detection of HBV P gene. Sixteen patients with untreated chronic hepatitis B had no YMDD variation. Seven of 22 patients with YMDD mutation had their liver function exacerbated. Among the patients with YIDD and YVDD variation, liver function exacerbated by 40.0% and 14.3% respectively. Among the patients with YIDD and YVDD variation, HBV DNA marked breakthrough by 70.0% and 25.0% respectively. Conclusion Comprehensive methods should be applied to increase the positive rate of PCR in the detection of variable region. Patients who were treated with lamivudine can induce HBV YMDD motif mutation, had their liver function deteriorated and HBV DNA breakthrough obviously.[Key Words] HBV DNA; quantification; polymerase chain reaction(PCR);liver function; breakthroughII. A new method of genotyping hepatitis B virus on the basis of restriction fragment length polymorphism of polymerase chain reaction products of the viral pres/s geneObjective To establish a new genotyping method for hepatitis B virus (HBV) on the basis of the pre-s gene. Method Based on the analysis of the restriction sites in the pre-s gene fragments of the 132 full-genomic sequences registered in the NCBI database, which had been classified into all known genotypes (A to G), BamH I, Ear I, Hpa II and Xho I were selected from the commercial restriction enzymes by the software of LaserGene 99. The polymerase chain reaction (PCR) products of the pre-s gene from 30 HBV DNA positive chronic hepatitis patients in Shanghai, China, were digested by the selected restriction enzymes. Result From the 30 subjects, 3, 25, 2 patients were classified as genotype B, genotype C and mixed genotypes of B and C respectively. Thirteen subjects of the total 30 ones were sequenced by direct sequencing of PCR products, which confirmed the PCR-RFLP genotyping method to be correct. Conclusion The HBV genotyping method developed by us is simple, accurate and economical. It is useful for large-scan epidemiological investigations and for studying the potential influence of genotype on the natural course of infection, prognosis of the disease and the outcomes of different therapeutic strategies. Genotype C of HBV is prevalent in the chronic hepatitis patients in Shanghai, China.[Key words] hepatitis B virus; genotyping; restriction fragment length polymorphism; pres/s geneHI. Evaluation of foscarnet sodium in the treatment of chronic hepatitis B Objective To investigate the effectiveness of foscarnet sodium in the treatment of patients with various types of chronic hepatitis B. Methods Forty-seven patients with different types of chronic hepatitis B were assigned to receive foscarnet sodium twice daily, 3.0g , given by intravenous infusion in addition to general therapy for 15 days. General therapy was given to twenty patients w...
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