[Gene therapy for tongue carcinoma mediated by oral administration of attenuated Salmonella harboring tip30 and IFN-γ genes in nude mouse model].

PURPOSE: To observe the effect of gene therapy mediated by oral administration of attenuated Salmonella carrying tip30 and IFN-γ genes in human tongue carcinoma nude mouse model. METHODS: 25 four-week-old BALB/C male nude mice were divided randomly into 5 groups based on the differently harboring genes in the recombinant attenuated Salmonella typhimuriums SL7207, which included blank group (PBS), control group (SL7207), IFN treatments group (SL7207-pCI-IFN), tip30 treatment group (SL7207-pCI-tip30) and the combination of IFN and tip30 treatment group (SL7207-pCI-tip30/IFN). On 10d after submandibular subcutaneous injection of Tca8113 cells into the mice, the recombinant attenuated Salmonella typhimuriums were orally administrated 3 times at 1 week interval. The treatment effect indicators included the growth curve, the tumor inhabitation rate, the survival rate, the apoptosis typical DNA ladder and the protein expressions of tip30 and IFN-γ in tumor cells. Statistical analysis was performed with SPSS15.0 software package. RESULTS: The growth curve, the tumor inhabitation rate and the survival rate indicated that the tumor in the PBS group constantly grew up and induced the animal death in earlier time, while the SL7207 treatment had a slight inhibiting effect compared with PBS group. However, the SL7207-pCI-IFN group and the SL7207-pCI-tip30 had a moderate inhibiting effect compared with the SL7207 group, while the combination of IFN and tip30 had the strongest inhibiting effect. The protein expressions of tip30 and IFN-γ were detected in tumor cells while the typical DNA ladders of apoptosis were observed only in the tip30 gene transfer groups (SL7207-pCI-tip30 and SL7207-pCI-tip30/IFN). CONCLUSIONS: The recombinant attenuated Salmonella typhimurium possesses a capacity of gene transfer in vivo through oral administration. The combination of the harboring tip30 and IFN-γ genes have synergistic inhibiting tumor effect for tongue carcinoma.

[Clinical evaluation of two light cured pit and fissure sealants for preventing pit and fissure caries in children].

PURPOSE: To evaluate the clinical effect of two light cured pit and fissure sealants for preventing pit and fissure caries. METHODS: 416 health permanent teeth in 162 children aged 6 to 8 years old children were divided into two groups, enameloplasty sealant technique (EST) and cup-shaped brush sealant technique (CST) were used in two groups, respeitively. 90 and 112 contralateral healthy teeth were used as self controls respectively. The rate of the sealant reservation and the incidence of caries were compared in the two groups, and the clinical effect of the two groups was compared using SPSS10.0 software package for Chi-square test. RESULTS: After 3 years, the rate of the sealant reservation and the incidence of caries of EST were 85.4% and 0.9% respectively, the rate of the sealant reservation and the incidence of caries of CST were 63.8% and 6.7% respectively. Statistical analysis revealed a significant difference (P<0.05) between the two groups. CONCLUSION: EST and CST both have good clinical effects, While EST is superior to CST in preventing pit and fissure caries.

[Primary culture and identification of mouse odontoblast-like cells].

PURPOSE: To culture primary mouse odontoblast and to provide a base for study on inducing ES cells to odontoblast. METHODS: Lower incisor germs were removed from 1-week-old mouse. The dental papillae were isolated in microscope, and the dental papillae cells were dispersed using 0.25% collagenase and 0.25% trypsin. The cell clones, which had similar morphology to odontoblasts, were selected for further culturing. The primary cultured cells were identified by light and electron microscopes and mRNA expression of mouse dentin sialophoprotein. RESULTS: The cultured cells had the same morphology and ultrastructure. They were rich in Golgi's complex, ribosome and rough endoplasmic reticulum. These cells expressed DSPP at mRNA levels. CONCLUSION: The cultured cells were mouse odontoblast-like cells. The method could be used for the study of odontal cells in vitro.

[A three-year clinical evaluation of ceramic optimized polymer posterior inlays].

PURPOSE: To evaluate the clinical results of ceramic optimized polymer (Targis) posterior inlays. METHODS: 345 type I cavities were divided into two groups: 170 in Targis inlays group (42 premolars and 128 molars) and 175 in control group (composite resin inlays, 45 premolars and 130 molars). The clinical effects of Targis inlays and composite resin inlays in posterior teeth were compared in marginal discoloration, marginal adaption, secondary caries, anatomic shape integrity, fractures of tooth and color match 3 years later. The data were analyzed using Chi-square test. RESULTS: 3 years after treatment, 166 Targis inlays were followed up, 2 had marginal discoloration, 158 had good marginal adaption, 162 had anatomic shape integrity, 1 had secondary caries, 161 had color match, and 5 had fractures of teeth. 169 composite resin inlays were followed up, 27 had marginal discoloration, 134 had good marginal adaption, 150 had anatomic shape integrity, 20 had secondary caries, 164 had color match,5 had fractures of teeth. The marginal discoloration, marginal adaption, secondary caries, anatomic shape integrity of Targis inlays were better than that of composite resin inlays (P < 0.05), but fractures of teeth was not different between inlays in the two group (P > 0.05). CONCLUSION: Targis posterior inlays is a good newly developed prosthesis.

[Induction of mouse embryonic stem cells forming odontoblast-like cells by co-culture with pulp fibroblast].

PURPOSE: To investigate the methods of induction of mouse embryonic stem cells to differentiate into odontoblast-like cells by co-culture with pulp fibroblast. METHODS: By suspension culture, embryonic stem cells were induced to form embryoid bodies. Then the cells from embryoid bodies were co-cultured with pulp fibroblast in Transwell system for differentiation toward odontoblast-like cells. RESULTS: By RT-PCR analysis, embryoid body cells gave rise to the cell population expressing DSPP, a specific odontoblast cell marker, after 10 days of co-culture with pulp fibroblast and the expression of DSPP was enhanced after 15 days of co-culture. On the other hand, the expression of DSPP was not detected in the isolately cultured embryoid body cells. CONCLUSIONS: Embryonic stem cells can be induced into odontoblast-like cells by co-culture with pulp fibroblast. Supported by Science and Technology Development Fund of Shanghai Municipality (Grant No. 03ZR14027).