[Study on antimicrobial effect of the mixture of Chinese medicine-chitosan to Candida albicans and the possibility as denture adhesive].

PURPOSE: To observe the antimicrobial effect and the tensile bond strength of water-soluble chitosan after adding different Chinese medicines to Candida albicans. METHODS: The extract of 6 kinds of Chinese medicine by decoction in different concentrations were mixed with chitosan, and the most effective mixture inhibiting Candida albicans and the minimal inhibitory concentration (MIC) were explored; Then the tensile bond strength of the mixture was tested and compared with Protefix denture adhesive. The data was analyzed with SPSS17.0 software package. RESULTS: The antibacterial effect of polyphylla-chitosan mixture was the best among the 6 kinds of Chinese medicine- chitosan mixture, and its MIC was 1.563 mg/mL. The tensile bond strength of polyphylla-chitosan mixture at 0 h and 12 h when immersed in artificial saliva were significantly larger than Protefix denture adhesive. The average value and the maximum value was significantly greater than the Protefix denture adhesive (P<0.05). CONCLUSIONS: Polyphylla-chitosan mixture has good antibacterial effect on Candida albicans and large tensile bond strength.

[Correlation analysis of VEGF and PTEN expression in gingival carcinoma].

PURPOSE: To study the expression of vascular endothelial growth factor (VEGF) and phosphatase and tensin homolog (PTEN) in gingival carcinoma and their correlation in order to provide reference for clinical treatment. METHODS: Sixty-six gingival cancer patients were determined by pathological examination, among which 31 were well-differentiated, 20 were moderately differentiated and 15 were poorly differentiated. 15 adjacent normal tissues were chosen as control group. The expression of VEGF and PTEN was examined by immunohistochemical method. Correlation analysis was performed with SPSS13.0 software package. RESULTS: The positive rate of PTEN in control group was significantly higher than other groups (P<0.05). The expression of VEGF in poorly differentiated group was significantly higher than other groups (P<0.05). Correlation analysis showed that the expression of VEGF was positively correlated to recurrence and lymph node metastasis (P<0.05); PTEN was negatively correlated to recurrence and lymph node metastasis (P<0.05); VEGF and PTEN in gingival carcinoma was negatively correlated (P<0.05). CONCLUSIONS: The increased expression of VEGF and decreased expression of PTEN in gingival carcinoma may play a mutual role in the development of gingival cancer.

[Structure and function of 3'- untranslated region in picornavirus].

Both sides of the picornavirus genome have 5'-untranslated region (5'UTR) and 3'- untranslated region (3'UTR). This study demontrated that both the 5'-and 3'-UTR can form complex structures, such as stem-loop, clover and pseudoknot structure, These structures play an important role in the regulaton of the replication and translation of the viruses. This article reviewed the progress of research on the structure and function of picornavirus' 3'-UTR over recent years.

[Effect of three dental alloys on cytotoxicity and apoptosis related gene expression in L929 cells].

PURPOSE: To investigate the effect of the liching liquids of 3 different kinds of dental alloys on L929 cells both at cell level and molecular level. METHODS: The fibroblast L929 cells of mouse were treated in vitro with leaching liquids of 3 different kinds of dental alloys which were Au alloy, Ti and Ni-Cr alloy, respectively. The RPMI 1640 cell medium containing 10% fetal calf serum was served as a negative control and the Cu alloy was served as a positive control. The cytotoxicities of 3 dental alloys were evaluated by means of MTT and the effects of these alloys on the expression of caspase-3, caspase-8 and caspase-9 of L929 cells were examined by RT-PCR method and immunohistochemistry. The data was analyzed with SPSS13.0 software package. RESULTS: The cytotoxicity of three groups were all in grade 0 after 48 hours of cultures. Caspase-8 had no change in all groups at mRNA level.The expression of caspase-3 and caspase-9 in Ni-Gr alloy group was significantly different from other groups. CONCLUSIONS: It is suggested from the results that the leaching liquids of Ni-Cr alloy may induce cell apoptosis through mitochondrion pathway.

[Application of custom casting separate post-and-core crown restorations of titanium in molar defects with low occlusogingival distance].

PURPOSE: To evaluate the clinical effect of custom casting separate post-and-core crown restorations of titanium in residual molar roots and crows with low occlusogingival distance. METHODS: Twenty-two residual roots and crowns with low occlusogingival distance were involved in the study. The root canals were prepared according to their natural directions without concerning about the common path of insertion and then the preparation of abutment teeth were made following the routine clinical procedure. Accurate impression was taken with silicone to fabricate the custom casting separate post-and-core crown restorations of Ti. The two parts were cemented together with resin cement. RESULTS: All the 22 fixed restorations were found to be with good retention and without looseness, falling off or breaking off of the roots.They all used normally for 6-30 months. CONCLUSIONS: Custom casting separate post-and-core crown of Ti is a better prosthetic restoration for molar residual root and crown with low occlusogingival distance.

[Study of Ag-containing on casting cobalt chromium alloy on the surface structure and the cell toxicity in vitro].

OBJECTIVE: To detect cobalt chromium alloy antimicrobial coating silver of the surface structure and the cell toxicity in order to provide a theoretical basis for clinical application. METHODS: Plasma spraying technique was adopted to prepare cobalt chromium alloy antimicrobial coating silver. Scanning electron microscopy, energy dispersive analysis and X-ray diffraction analysis were used to evaluate the surface properties. The methyl thiazolyl tetrazolium and flow cytometry method was adopted to test the L929 cell proliferation and the influence of the cell cycle. RESULTS: The surface of the coating was uniform and compact, combined perfectly with substrate material. The content of the surface was mainly Ag, Cr and a small amount of Ag(2)O, Cr(2)O(3). After cobalt chromium alloy was cultured in leach liquor for 1, 2 and 3 days, the statistical result showed that there was no significant different between the three groups. The cytotoxic level of negative control group was level 0 at each time point and that of other groups was level 1 at each time point. There was no significant difference between cobalt chromium alloy and cobalt chromium alloy antimicrobial coating silver in cell toxicity (P > 0.05). There was no statistical significance of the influence on cell cycle between cobalt chromium alloy with Ag coating [the G2's rate of cell cycle was (8.23 ± 0.39)%] and cobalt chromium alloy group [the G2's rate of cell cycle was (8.70 ± 0.46)%] (P > 0.05). CONCLUSIONS: The surface of the coating was stable and there was no significant difference between cobalt chromium alloy widely used in clinic and cobalt chromium alloy with Ag coating of the influence on proliferation of L929 cell and cell cycle, the cell compatibility of cobalt chromium with Ag coating is well.

[Study on the current status of spontaneous abortion of primigravid women in Jiaxing of Zhejiang province, China].

OBJECTIVE: To study the current status of spontaneous abortion of primigravid women in Jiaxing areas of Zhejiang province of China. METHODS: We analyzed the data from both perinatal healthcare surveillance program and spontaneous abortion, collected in Jiaxing areas by the Institute of Reproductive and Child Health, Peking University. The study population consisted of 14 769 primigravid women (excluding induced abortion, ectopic pregnancy and molar pregnancy as outcomes) attempting to become pregnant who registered between 1993 and 1995. RESULTS: 1454 spontaneous abortion cases were identified, with the spontaneous abortion rate as 9.8% (95%CI: 9.3% - 10.3%). The mean gestational weeks at pregnancy diagnosis were 7.6 ± 2.1 weeks, the mean gestational weeks at miscarriage were (10.1 ± 3.1) weeks and the incidence of first-trimester (≤ 12 weeks) spontaneous abortion was 7.3% (95%CI: 6.8% - 7.7%), accounting for 73.7% of all the spontaneous abortion cases. A peak for risk of miscarriage was around 8 - 13 weeks, accounting for 37.7% of all spontaneous abortion. The observed multiple Cox regression model showed that increased spontaneous abortion rates were observed in women with age at pregnancy ≥ 30, being peasants and with higher education level. CONCLUSION: The spontaneous abortion rate of primigravid women in Jiaxing areas was higher than in other areas of China. The maximum occurrence of spontaneous abortions was during period of 8-13 gestation weeks.

[Effect of different heat treatment on mechanical properties and microstructure of laser welding CoCr-NiCr dissimilar alloys].

OBJECTIVE: To evaluate the effect of heat treatment and porcelain-fused-to-metal (PFM) processing on mechanical properties and microstructure of laser welding CoCr-NiCr dissimilar alloys. METHODS: Samples of CoCr-NiCr dissimilar alloys with 0.5 mm thickness were laser-welded single-side under the setting parameters of 280 V, 10 ms pulse duration. After being welded, samples were randomly assigned to three groups, 10 each. Group1 and 2 received heat treatment and PFM processing, respectively. Group 3 was control group without any treatment. Tensile strength, microstructure and element distribution of samples in the three groups were tested and observed using tensile test, metallographic examinations, scanning electron microscope (SEM), and energy dispersive spectroscopy (EDS) analysis. RESULTS: After heat treatment and PFM processing, tensile strength of the samples were (537.15 +/- 43.91) MPa and (534.58 +/- 48.47) MPa respectively, and elongation rates in Group 1 and 2 were (7.65 +/- 0.73)% and (7.40 +/- 0.45)%. Ductile structure can be found on tensile fracture surface of samples and it was more obvious in heat treatment group than in PFM group. The results of EDS analysis indicated that certain CoCr alloy diffused towards fusion zone and NiCr side after heat treatment and PFM processing. Compared with PFM processing group, the diffusion in the heat treatment group was more obvious. CONCLUSIONS: Heat treatment and PFM processing can improve the mechanical properties and microstructure of welded CoCr-NiCr dissimilar alloy to a certain degree. The improvements are more obvious with heat treatment than with porcelain treatment.