[Inhibition of hepatitis C virus replication by mycophenolic acid in hepatocytes].

OBJECTIVE: It is well known that cyclosporine A (CsA), a widely used immunosuppressant for clinical organ transplantation, has the ability to inhibit HCV replication. In this study, the effects of several other immunosuppressants, including mycophenolic acid (MPA), rapamycin and FK-506, on HCV replication were examined in human hepatocytes. METHODS: HCV JFH-l-infected hepatocytes were treated with immunosuppressants or with control vehicles. The levels of viral RNA and the expression of HCV core protein were determined by quantitative real-time RT-PCR and Western Blot assay, respectively. RESULTS: MPA-treated cells showed significant decreases in both viral RNA and HCV Core protein expression compared with the control cells. Moreover, MPA treatments of hepatocytes before, during or after HCV infection could significantly inhibit viral replication. In contrast, rapamycin and FK-506 had little effect on HCV replication. Mechanism research disclosed that the inhibition of HCV replication by MPA was mainly due to its depletion of guanosine, a purine nucleoside crucial for synthesis of guanosine triphosphate (GTP), which is required for initiation of HCV RNA replication. The supplement of exogenous guanosine could reverse most of anti-HCV effect of MPA. CONCLUSION: These results indicate that MPA, through the depletion of guanosine, inhibits HCV JFH-1 replication in hepatocytes, suggesting that MPA may be beneficial for HCV-infected transplant recipients.

[Establishment and evaluation of a Chinese rhesus model of tuberculosis].

OBJECTIVE: To establish and evaluate the Chinese rhesus model of tuberculosis. METHODS: Twelve Chinese rhesus macaques, randomly divided into 3 groups, were inoculated with 2 different doses of Mycobacterium tuberculosis H(37) Rv strain via both bronchoscopic and intratracheal instillation into the lungs. Clinical observation and laboratory examinations were performed, including erythrocyte sedimentation rate, C-reactive protein, tuberculin skin test and X-ray examination. Histopathological assessments were performed in the 24th week postinfection. Statistical analysis was performed by ANOVA in the 3 groups. RESULTS: After infection all the animals manifested fever, weight lose, lack of appetite, coughing and other symptoms of tuberculosis. The temperature gradually increased and reached a peak [(40.1 ± 0.2)°C] at the 8th week postinfection. The weight decreased significantly at 24th week postinfection (-5.5 ± 5.6)%. Erythrocyte sedimentation rate elevated significantly at the 6th to 8th week postinfection (36 ± 40) mm/1 h. C-reactive protein was significantly increased at the 6th to 24th week after infection (75.8 ± 49.8) mg/L. The positive rate of tuberculin skin test was 100%. In Group I (bronchoscopic instillation, 20 CFU) the disease developed slowly, and the main manifestation of chest X-ray was patchy shadows. In group II (bronchoscopic instillation, 100 CFU) and group III (intratracheal instillation, 100 CFU) the disease developed rapidly, and the main manifestation of chest X-ray was patchy and nodular lesions during the 4th to the 12th week postinfection, but became large patchy and consolidation lesions during the 12th to the 24th week postinfection. Tuberculosis granuloma and caseous necrosis, similar to the pathological changes of human tuberculosis, were found in the lungs, mediastinal lymph nodes, kidney and spleen. The results of acid-fast stain were positive. The most serious pathological manifestations were observed in group II, followed by group III and group I. The highest bacterial load of the right lung was seen in group II, followed by group I and group III. CONCLUSIONS: A chinese rhesus model of tuberculosis was successfully developed via both bronchoscopic and intratracheal instillation. Their clinical manifestations, disease progression and pathological changes were similar to human primary tuberculosis and hematogenous disseminated tuberculosis.

[Study on the distribution of hepatitis C virus genotypes in patients visiting one methadone maintenance clinic in Wuhan].

OBJECTIVE: To study the prevalence of hepatitis C virus (HCV) infection and characteristics on molecular biology related to HCV among patients who were enrolled in a Methadone maintenance clinic in Wuhan. METHODS: Serum samples from 332 injection drug users (IDUs) were obtained and anti-HCV IgG was detected by enzyme linked immunosorbrent assay(ELISA), together with 86 anti-HCV positive specimens genotyped. A reverse transcriptase-polymerase chain reaction (RT-nPCR) assay using conserved primers deduced from the core-envelopel (C-E1) region of the HCV genome was employed to amplify a 474 bp fragment. Phylogenetic analysis of the C-E1 sequences was conducted by direct sequencing of the RT-nPCR products and alignment with determined by nucleotide sequencing followed by composition of a phylogenetic tree. RESULTS: There were 313 cases (94.3%) appeared positive anti-HCV IgG in the 332 patients from a Methadone maintenance clinic in Wuhan. It was demonstrated that there were four different subtypes of HCV in that clinic in Wuhan, including 6a--71 cases (82.5%), 3b--7 cases (8.2%), 1a--5 cases (5.8%) and 1b--3 cases (3.5%). CONCLUSION: Infection of 6a genotype HCV was predominant in patients from the Methadone maintenance clinic in Wuhan, followed by HCV 3b, 1a and 1b.