Severe acute respiratory syndrome (SARS) is a newly discovered infectious disease that greatly threatens human health in the 21st centry. In this article the author elucidates the current status and problems and difficulties encountered in the specialty of lemology as experienced in personal practices in an epidemic of SARS in China, and ventures to present several personal opinions in this regard.

Chronic hepatitis B virus infection is a great threat to public health around the world.National,Asian-Pacific,or global clinical research collaborative network plays an important role in exploring new therapeutic strategies and biological markers and preventing mother-to-child transmission of hepatitis B.We believe that such network may help to realize a future without hepatitis B.

Molecular biological methods were used to construct the eukaryotic expression vectors of precore and core gene named EBO PreC/C. Then T1862, A1896, A1899 and A1896+A1899 variants were constructed by site mutagenesis in vitro. By PCR RFLP and sequencing ,T1862,A1896,A1899 and A1896+A1899 variants were obtained. Wild type and variants were transfected to HepG2 cells, and HBeAg was tested to observe the difference of HBeAg expression between wild type and variants. After stable expression in HepG2 cells, HBeAg was detected to be positive in cells transfected wild type and A1899 variants, and negative in cells transfected with T1862, A1896,A1896+A1899 variants. The construction of these variants will play an important pole in studying the relation of PreC/C mutations and HBV expression and replication of HBV genome.

Objective A method was established for genotyping of hepatitis B virus (HBV),based on the restriction fragment length polymorphism(RFLP)created by BsrI, StyI,DpnI and HpaII action on an amplified segment of the S region. Methods 223 full-genomic sequences were analyzed and the aligned nucleotide and amino acid sequences of S gene, genotype specific regions were identified by the restriction enzymes, BsrI, StyI,DpnI and HpaII. Pre S PCR-RFLP genotyping method was applied to a number of serum samples from hepatitis B e antigen (HBeAg) positive and negative Chinese chronic HBV carriers. And in 90 samples the following genotypes were observed: 30B, 30 C, 30D. The method using S gene PCR-RFLP was confirmed to be correct by these 90 samples. Three samples of each genotype B, C and D were randomly selected and directly sequenced their S gene to confirm that HBV S gene PCR-RFLP genotyping method was correct disectly. Results The results of two PCR-RFLP HBV genotyping methods were coincide with that of S gene sequence. Conclusions The method for genotyping of hepatitis B virus (HBV), based on S gene RFLP is established to be highly sensitive, differential and accurate. The RFLP patterns are easy to be recognized because of its simplicity and singleness.

Objective In order to further study the influence of a mutant on viral replication and transfection, a eukaryotic vector with mutation of 20/21 bp deletion (1748/ 1747 to nt 1767) in core promoter region and precore stop mutation (nt.1896) was constructed. Methods A linearized genome containing the entire HBV 3.5kb mRNA transcriptional units (P3.8Ⅰ vector) and initiating from the basic core promoter upstream sequences was used as a tool, the objective eukaryotic vectors were constructed by the molecular cloning and PCR based site directed mutagenesis in vitro. The capability of progeny virus production and transcription were examined with Southern blot and Northern blot analysis respectively, after transfection of the recombinant HBV plasmids into HepG2 cells by using liposome. Results The eukaryotic vectors were constructed successfully and their sequences were confirmed by clone sequencing. Both Southern and Northern blotting of DNA and RNA extracted from the transfected cells showed markedly reduced mutant activity to produce progeny virus, to transcript both 3.5kb precore/pregenome mRNA and 2.1kb preS/S mRNA. Conclusions The levels of replication and transcription are markedly reduced in the mutant compared with those in wild type HBV.

Objective To explore the information on the clinical features of the severe acute respiratory syndrome (SARS) prevalent recently. Methods We collected and analyzed clinical date from the 85 inpatients suffered from SARS in Nanfang Hospital, Guangzhou. Results The patients ranged from 4 to 87 years old (mean age 38.2?16.7 years). The incubation period ranged form 2 to 16 days (mean periods 7.4? 3.8 days). The most common symptoms included fever (in 97.8 percent of the patients), cough (81.2%), malaise (74.1%), headache (63.5%), myalgia (41.2%). Peripheral vein blood test showed normal leukocytes and leukopenia in 82.4 percent of the patients. Other common findings were lymphopenia (in 27.1 percent of the patients), elevated alanine aminotransferase (44.7%), elevated aspartate aminotransferase (57.6%), elevated lactase dehydrogenase (49.4%) and elevated creatinine kinase (20.0%). Chest radiographs predominately showed air-space shadowing, such as ground-glass opacities, focal consolidation or patchy consolidation. The air-space shadowing was mostly in the lower lung zones (in 88.3 percent of the patients, bilateral and unilateral for 51.8% and 36.5% respectively). The mean period of complete resolution of the air-space shadowing was 20.3?8.4 days and 13.1?6.9 days after onset of illness and absent fever respectively. Empirical therapy most commonly included ribavirin, antibiotics. Conclusions SARS appears to be infectious. Fever followed by rapidly progressive respiratory compromise is the key complex of signs and symptoms from which the syndrome derives its name.

Objective To explore the relationship between hepatitis B virus (HBV) genotype and outcome of HBV infection. Methods PCR amplification of HBV small S gene in combination with a restriction fragment length polymorphism (RFLP) analysis was applied to identify HBV genotype in the serum samples of 80 asymptomatic HBV carriers (AsC group) and 120 liver cirrhosis patients with HBV infection (LC group) in Gangdong province of China. Results The frequency of HBV genotypes B, C and D in AsC group was 45% (37/80), 33.75%(26/80) and 21.25%(17/80)respectively, and that of HBV genotypes B, C and D in LC group was 32.5%(39/120), 65.8%(79/120) and 1.6%(2/120) respectively. There is no HBV genotypes A, E and F in this series. The distribution of HBV genotypes in the two groups was not significant correlation with the state of HBeAg. There was a significant difference in the distribution of HBV genotypes between the two groups (P

Objective To compare the occurrence of YMDD mutations in patients with HBeAg positve and HBeAg negative chronic hepatitis. Methods Two hundred and forty seven chronic hepatitis B patients who received lamivudine treatment were followed up.Liver function tests and hepatitis B virological tests including YMDD mutant analysis,HBV DNA quantitation and HBV serological marker analysis were performed regularly. Results YMDD mutants were detected in forty two patients.The cumulative rate of occurrence of YMDD mutation increased with the duration of lamivudine treatment.The mutation rate was significantly higher in pretreatment HBeAg positive patients than that in HBeAg negative patients.The ALT flare was more evident after emergence of YMDD mutants in pretreatment HBeAg positive patients than that in HBeAg negative patients.Conclusions The cumulative rate of occurrence of YMDD mutation was higher in pretreatment HBeAg positive patients than that in pretreatment HBeAg negative patients.

Humans ; Liver Cirrhosis