[Effect of polishing method and time on the fitness of CAD/CAM zirconia ceramic crown].

PURPOSE: To compare the effect of different polishing methods and time treatment on the fitness of CAD/CAM zirconia ceramic crowns. METHODS: Sixteen intact maxillary premolars were randomly divided into two groups, group A was treated with silicon carbide burs, while group B was treated with tungsten steel burs. At different polishing time points of the same tooth, digital impressions of each group were obtained, which were used to manufacture CAD/CAM zirconium ceramic crowns. After trial fitting, the gap impressions were obtained by using silicone rubber replication method, and the marginal and internal discrepancies were assessed. The data were statistically analyzed with SPSS 21.0 software package. RESULTS: The difference between the gap values of the marginal and internal markers of group A and group B was not statistically significant(P＞0.05). Compared with the no-polishing process, the differences of the marginal gap (39.67±8.35) µm and internal gap (45.18±7.16) µm of group A polished for 4 min, and the marginal gap (51.25±14.73) µm, and internal gap (48.56±6.45) µm of group B polished for 3 min, as well as the marginal gap (48.87±8.90) µm, and internal gap (45.99±7.12) µm of group B polished for 4 min, were all significant(P＜0.05). CONCLUSIONS: CAD/CAM zirconia ceramic crowns treated with silicon carbide bur for polishing 4 min and tungsten steel for 3 min has the best fitness.

Investigation and analysis of antibody levels of hepatitis A among children before and after implementing the Expanded National Immunization Program in China.

OBJECTIVE: To analyze changes of hepatitis A antibody levels and immunization coverage of HAV vaccine among children before and after implementing the Expanded National Immunization Program in five counties of China, and to provide evidence for developing hepatitis A vaccine immunization strategies. METHODS: 449 children born in 2001, 2005 and 2009 were selected from five counties for an immunization coverage and a sero-prevalence survey of hepatitis A. The chemiluminescence microparticle immunoassays (CMIA) were used to detect hepatitis A IgG antibody and analyzed the factors which influenced the immunization coverage and positive rates. RESULTS: Among 449 subjects of children born in 2001, 2005 and 2009, the immunization coverage were 53.02%, 78.52% and 99.34% (χ2 = 91.285, P < 0.001). The positivity rates of hepatitis A IgG antibody were 61.07%, 81.21%, 95.36% (χ2 = 54.198, P < 0.001), respectively. The immunization coverage and positivity rate significantly increased with the delay of birth year. Children accepting different doses of HA vaccines are significantly different in positive rates of HA antibody, while there are no significant differences of different genders, years of birth, residence types, or types of registered permanent residence in different regions. The positivity rate increased significantly with administration of hepatitis A vaccine and shorter intervals between sample collection and HAV immunization. CONCLUSIONS: After the Expanded National Immunization Program was implemented, hepatitis A antibody levels were significantly increased in five counties, which indicates a successful result of EPI.

Involvement of de novo ceramide synthesis in pro-inflammatory adipokine secretion and adipocyte-macrophage interaction.

Interaction between adipocytes and macrophages has been suggested to play a central role in the pathogenesis of obesity. Ceramide, a sphingolipid de novo synthesized from palmitate, is known to stimulate pro-inflammatory cytokine secretion from multiple types of cells. To clarify whether de novo synthesized ceramide contributes to cytokine dysregulation in adipocytes and macrophages, we observed cytokine secretion in mature 3T3-L1 adipocytes (L1) and RAW264.7 macrophages (RAW) cultured alone or co-cultured under the suppression of de novo ceramide synthesis. Palmitate enhanced ceramide accumulation and stimulated the expression and secretion of interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1) in L1. The suppression of serine-palmitoyl transferase, a rate-limiting enzyme of de novo ceramide synthesis, by myriocin or siRNA attenuated those palmitate-induced alterations, and a ceramide synthase inhibitor fumonisin B1 showed similar results. In contrast, the inhibitor of sphingosine kinase or a membrane-permeable ceramide analogue augmented the cytokine secretion. Myriocin effects on the palmitate-induced changes were not abrogated by toll-like receptor-4 blockade. Although palmitate stimulated RAW to secrete tumor necrosis factor-α (TNF-α), it did not significantly increase ceramide content, and neither myriocin nor fumonisin B1 attenuated the TNF-α hypersecretion. The co-culture of L1 with RAW markedly augmented IL-6 and MCP-1 levels in media. Myriocin or fumonisin B1 significantly lowered these cytokine levels and suppressed the gene expression of TNF-α and MCP-1 in RAW and of IL-6 and MCP-1 in L1. In conclusion, de novo synthesized ceramide partially mediates the palmitate effects on pro-inflammatory adipokines and is possibly involved in the interaction with macrophages.

Prevalence of occult hepatitis B virus infection among hepatopathy patients and healthy people in China.

OBJECTIVE: To investigate the prevalence of occult hepatitis B virus (HBV) infection among hepatopathy patients and healthy people in China. METHODS: The HBV DNA in 653 sera samples collected from cryptogenic chronic liver disease patients (159), hepatitis B surface antigen (HBsAg) negative hepatocellular carcinoma (HCC) patients (135) and HBsAg-negative healthy people (359) were tested by nested PCR using specific primers of the X region of the HBV genome. We performed real-time PCR to determine the levels of serum HBV-DNA. RESULTS: Prevalence of occult HBV infection was 28.3% (45/159), 70.4% (95/135) and 10.6% (38/359) in cryptogenic chronic liver disease patients, HBsAg-negative HCC patients and HBsAg-negative healthy people, respectively. The prevalence of occult HBV infection in IgG anti-HBc-positive subjects was 100% (45/45), 86.7% (85/98) and 33.3% (14/42) in cryptogenic chronic liver disease patients, HBsAg-negative HCC patients and HBsAg-negative healthy people, respectively. In all cases, viral loads were low (<10(4)viral copies/mL). CONCLUSION: The prevalence of occult HBV infection was significantly high among hepatopathy patients and healthy people in China. Thus, more meticulous attention should be given to prevent HBV transmission by blood transfusion or organ transplantation in endemic areas, and further studies on clinical implication and mechanism of occult HBV infection are required.

Construction and expression of eukaryotic plasmids containing lamivudine-resistant or wild-type strains of Hepatitis B Virus genotype C.

AIM: To construct eukaryotic expression plasmids of full-length Hepatitis B Virus (HBV) genotype C genome, which contain lamivudine-resistant mutants (YIDD, YVDD) or wild-type strain (YMDD), and to observe the expression of HBV DNA and antigens [hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg)] of the recombinant plasmids in HepG2 cells. METHODS: Three HBV full-length genomes were amplified from the plasmids pMD18T-HBV/YIDD, pMD18T-HBV/YVDD and pMD18T-HBV/YMDD, using PCR. Three recombinant plasmids were generated by inserting each of the PCR products into the eukaryotic expression vector pcDNA3.1 (+), between the EcoRI and HindIII sites. After being characterized by restriction endonuclease digestion, and DNA sequence analysis, the recombinant plasmids were transfected into HepG2 cells. At 48 and 72 h post-transfection, the levels of intracellular viral DNA replication were detected by real-time PCR, and the expression of HBsAg and HBeAg in the cell culture supernatant was determined by ELISA. RESULTS: Restriction endonuclease digestion and DNA sequence analysis confirmed that the three recombinant plasmids were correctly constructed. After transfecting the plasmids into HepG2 cells, high levels of intracellular viral DNA replication were observed, and HBsAg and HBeAg were secreted into the cell culture supernatant. CONCLUSION: Eukaryotic expression plasmids pcDNA3.1 (+)-HBV/YIDD, pcDNA3.1 (+)-HBV/YVDD or pcDNA3.1 (+)-HBV/YMDD, which contained HBV genotype C full-length genome, were successfully constructed. After transfection into HepG2 cells, the recombinant plasmids efficiently expressed HBV DNA, HBsAg and HBeAg. Our results provide an experimental basis for the further study of HBV lamivudine-resistant mutants.