Hepatitis B virus(HBV) is a double-strand hepadnavirus.HBV genomics have unique properties:(1) Viral polymerase/reverse transcriptase(RT) is lacking in proofreading activity,leading to higher mutation occurrence than other DNA viruses.(2) Overlapping open reading frames in viral genomics may produce the possibility of mutation of two viral proteins mutation as a result of one-site genetic change.(3) A stable covalently closed circular DNA(cccDNA) form exists as an important intermediate in the life cycle.(4) Viral gene fragments may be integrated into host cellular genomic DNA.(5) Viral proteins could be a trans-regulator for certain host cellular protein expression.The virological characteristics of HBV are closely related with the chronicity and disease course of hepatitis B.Multi-site detection of HBV RT-gene mutations is very important for monitoring drug resistance and rational administration of anti-HBV therapy in clinic.Analysis of viral genomic variation and detection of cccDNA are highly valuable in better understanding virological pathogenesis and evaluate therapeutic efficacy.Methodological innovation and improvement is the basis for the study of virological characteristics of HBV.

Nucleoside analogs (NA) are currently the major anti-hepatitis B virus (HBV) agents in clinic. However,long-term use of NA may initiate a state of drug resistance due to HBV mutation. The genotyping and phenotyping are two basic methods for analysis of HBV drug resistance. Genotyping is done mainly by DNA sequencing and reverse hybridization line probe to detect the well-known drug-resistant mutations. Phenotyping is an essential tool used to identify "novel" and complex resistant mutations,and it is based on the comparison of HBV replication capacities of variants and wild-type counterparts by cell-transfer of individual viral genomes followed by quantitation of HBV replication intermediates in the presence of antivirals in different concentrations. Clinical choice of HBV resistance detection assays relies on their sensitivity,specificity and cost-effectiveness. In our recent studies,some novel HBV resistant features have been found,including multidrug-resistant strain with mutations due to the use of both entecavir and adefovir,association of HBV genotype/subgenotype with the resistant mutational patterns,transmission of the resistant HBV to cause acute hepatitis,replication compensation of rt229 variants,etc. These findings are important for better understanding the clinical features of HBV drug-resistant mutations and strengthening the management of HBV drug resistance in clinic.

Objective To compare the efficiency of detecting YMDD mutations by direct DNA sequencing and real time fluerescence PCR, and to explore the significance of the mutations of drug-resistance gene other than YMDD mutation. Methods 92 serum samples from 89 patients with chronic hepatitis B were collected and all the samples were detected by real-time PCR for YMDD mutation. HBV DNA was extracted from serum and was amplified by nest PCR to achieve HBV P gene RT region sequence. The PCR products were sequenced at both directions, and the sequencing results were contrasted through NTI program. The other 11 known drug-resistance mutation sites at the HBV RT region were also analyzed. Results Among the 37 samples with no YMDD mutation detected by real-time PCR, 33 samples were with M204M (without mutation), 1 sample with M204I and 3 samples with M204V by direct sequencing. Mutation and wild-type standard sequences were all coexisted in the 4 positive samples. There were 7 samples detected with ADV resistant mutation, accounting for 18.9% (7/37). Among the 55 samples with YMDD mutation detected by real-time PCR, 52 samples were detected by DNA sequencing, the accordance rate was 94.5% (52/55); 5 samples with ADV or ETV resistant mutation were detected, accounting for 9.1% (5/55). Conclusions Direct DNA sequencing is a high sensitive, repeatable method to detect drug-resistance mutation at RT region of HBV P gene. The result is well consistent with that attained by real-time PCR. Direct DNA sequencing can also detect various drug-resistance mutations as well as YMDD mutation, which is helpful to generally understand the nucleoside analogue resistant mutation and adopt more reasonable therapy projects against HBV.

Objective To investigate the effect of GABAB receptor in spinal cord by detecting semi-quantitatively the mRNA for isoforms of GABAB receptor in a chronic neuropathic pain model. Methods Twenty-four male SD rats weighing 200-250g were anesthetized with intraperitoneal pentobarbital. Lamina of L5 vertebra and superior articular process of L6 were removed and posterior root of left L5 spinal nerve was exposed and tightly ligated with 7/0 atraumatic suture. The animals were randomly divided into 4 groups of 6 animals in each group: group A in which animals were observed for 7 days after sham operation; group B in which animals were observed for 7 days after ligation of posterior root of L5 spinal nerve; in group C animals were observed for 14 days after sham operation and in group D animals were observed for 14 days after ligation. Pain threshold was measured by heat stimulation of bilateral hindlimbs before and on the 1st , 3rd , 7th , 10th and 14th day after operation. Lumbar spinal cord was removed on the 7th or 14th day after operation and mRNA for isoforms of GABAB receptor in the spinal cord was detected semi-quantitatively by digoxin hybridization in situ.Results Pain threshold of left hindlimb (ligated side) was significantly lower than that of right hindlimb on the 7th, 10th and 14th day after operation as measured by heat stimulation. There were less mRNA for three isoforms of GABAB receptor in group B and D as compared with group A and C respectively. Conclusion The gene expression of three isoforms of GABAB receptor in the spinal cord has plasticity and is reduced during chronic neuropathic pain.

To compare the clinical effect and side-effect of intravenous PCA(PCIA) with epidural PCA (PCEA). Method: One hundred and eighty postoperative patients, who were randomly divided into three groups: group PCIA, group PCEA and control, were observed for 3 days after operation. Result: Overall patients in two PCA groups were satisfied with the postoperative analgesia. The incidence of urinary retention in group PCIA were significantly lower than that in group PCEA (P0.05). 10% in group PCIA were in medium sedation whereas no eases in group PCEA were in sedation. At 6th hour after operation,serum cortisol level of control patients was much higher than that of PCA patients. Conclusion=Both PCIA and PCEA have excellent analgesia and reduce stress response after operation. PClA has lower incidence of urinary retention and is performed easily,but inhibits gastrointestinal motility much more and has higher sedative incidence compared with PCEA.

Objective To screen the down-regulated genes in HepG2 cells transfected by pcDNA3.1(-)-IFN-? to further investigate the biological mechanism of IFN-?. Methods pcDNA3.1(-)-IFN-? was transfected into HepG2 cells as treatment group and the pcDNA3.1(-) transfected cells as the control to perform suppression subtractive hybridization (SSH). The subtractive library for down-regulated genes was obtained when pcDNA3.1(-) transfected HepG2 as tester and pcDNA3.1(-)-IFN-? transfected cells as driver. A housekeeping gene, G3PDH, was used to estimate the subtractive efficiency. Genes with lower expressions in IFN-? transfected HepG2 cells were obtained from the library after being randomly sequenced and analyzed. Among the obtained genes, regulation of IFN-? on heat shock 90kD (Hsp90) mRNA was further investigated by RT-PCR. Results G3PDH was subtracted efficiently indicating that the subtractive library was constructed successfully. 50 positive clones were randomly isolated for PCR identification. Results showed that most of the plasmids in the clones contained 200-1 000bp inserts. The down-regulated genes obtained were as follows: eukaryotic translation elongation factor 1 beta, ferritin, RAD23 homolog B, signal sequence receptor 2 (SSR2), tissue factor pathway inhibitor, heat shock 90kD protein 1, and adenosylmethionine decarboxylase 1. RT-PCR showed that hsp90 mRNA had a reduced expression in pcDNA3.1 (-)-IFN-? transfected HepG2 cells. Conclusion The down-regulated cDNA subtractive library in HepG2 cells after pcDNA3.1 (-)-IFN-? transfection was constructed successfully. IFN-? could down-regulate the hsp90 mRNA expression.

Objective To investigate the expression of ERBB3 protein,which encoded by ERBB3 gene,in gastric cancer(intestinal type and diffuse type)as well as the normal tissue,and to elucidate the possible role of ERBB3 gene in the progress of gastric cancer.Methods 65 samples of gastric cancer tissue(of which 43 samples were intestinal type and 22 were diffuse type,classified according to the Lauren patho-classification)and 65 samples of normal tissue(control group)were investigated immunohistochemically.The expression of ERBB3 in both control group and gastric cancer group was determined.Comparisons were made according to different pathological types and TNM clinical stages within and between groups.Results 7 of 65 samples(10.8%)in gastric cancer group were found to over-express the ERBB3 protein,while only 1 of 65 samples(1.6%)in control group was found to over-express the ERBB3 protein.Statistical differences(P

Objective To serially examine virus carrying condition of clinical specimens collected from SARS patients, in order to evaluate the dynamic changes of virus in the bady and its clinical significance. Methods A total of 494 samples, including plasma, urine, feces, sputum and throat swab, obtained from 84 cases of clinically diagnesed SARS patients at different time-points were examined for the study. Nested RT-PCR was employed for the detection of SARS-CoV using 2 pairs of primers targeting P and N region of the viral genome. The amplified viral genomic fragments were confirmed by DNA sequence analysis. Results Specific bands for SARS-CoV were amplified from various specimens of some SARS patients. Highest positive rate was found in sputum compared with the others. However, simultaneous examination of more than two specimens increased detectable rate of the virus. Moreover, dynamic examination revealed that the highest positive rate occurred in the 2nd week after the onset of the disease and next to the highest during the 3rd to 4th week. However, dynamic detectable rates for different specimens were not identical. Conclusion Nested RT-PCR is a practicable method for the detection of SARS-CoV and helpful for the early diagnosis or confirmation of the disease. Dynamic examinations for SARS-CoV by combined employment of the N and P primers and by involving multiple specimens may significantly increase the positive detectable rate, therefore would be helpful in diagnosis and eratuation of therapeutic effect of SARS.

Objective To observe dynamic responsive regularity of specific IgM and IgG antibodies in SARS patients. Methods 145 specimens of plasma from 25 cases of clinically diagnosed SARS patients were examined in the study. ELISA was employed to detect IgM and IgG antibodies against SARS coronaviral antigens. Nested RT-PCR was used to qualitatively determine SARS coronavirus (SARS-CoV). Results 49.0% (71/145) and 54.5% (79/145) of the samples were positive for IgM and IgG antibodies, respectively. Both antibodies were found to be detected in 84.0% of the patients. The antibodies were found to be detectable from the 2nd to 4th week after the onset of disease in most patients, and there was a fendeney of sising in positive rate until the 5th week after the onset. Thereafter, the detectable rate of IgM antibody began to decline, while that of IgG antibody remained to rise. Positive rate for serum SARS-CoV was 15.8% (18/114) for all samples or 40.0% (10/25) of patients. Most virus-positive samples were those which were collected within 4 weeks after disease onset. Conclusions Anti-SARS-CoV IgM/IgG antibody and detection of virus in plasma could serve as practical diagnostic indicators for SARS. In most cases, when the serum was pasitive for antibody the serum virus positive rate would soon declined. However, concomitant existence of antibody and viral sequence in plasma was observed in a few patients.

Objective To investigate forkhead/winged helix transcription factor (FoxP3) expression in peripheral blood and liver-infiltrating lymphocytes (LIL) of patients with hepatitis B. Methods Flow cytometry, immunohistochemistry and real-time RT-PCR were employed for Fox P3 analysis of blood or live tissue obtained from patients with acute hepatitis B (AHB), chronic hepatitis B (CHB) and chronic severe hepatitis B (CSHB), as well as health controls. Results Fox P3 mRNA and protein expressions were specifically identified in CD4+CD25+ regulatory T cells. The level of Fox P3 mRNA in CD4+ T cells was identical with that in CD4+CD25+ regulatory T cell in peripheral blood. In CSHB patients a significant increase of Fox P3 mRNA expression was found in peripheral blood. The mean relative FoxP3 mRNA levels of CD4+ T cells in CSHB patients, AHB patients, CHB patients, and healthy controls were 0.199?0.174, 0.053?0.017, 0.059?0.053, and 0.056?0.021, respectively (CSHB group vs. other groups, P all