[Effects of lyophilized on the biological activities of lentiviral vector of bone morphogenetic protein 2].

PURPOSE: To investigate the influence of lyophilization on the biological activity of recombinant lentiviral vectors of bone morphogenetic protein 2(BMP-2). METHODS: Recombinant lenti-BMP-2 was constructed. lenti-BMP-2 was transfected with rat bone marrow stromal cells (BMSCs) by multiplicity infection (MOI) of 10, 25, 50, 100, 200. The infection efficiency was observed by X-gal staining. Under suitable conditions, the lenti-BMP-2 and 10% trehalose ratio of lyophilized protective agent was mixed into the lyophilization form. Before and after lyophilization, the effect of lenti-BMP-2 on the proliferation of BMSCs was evaluated by MTS assay. The expression of BMP-2 protein in the cells of lyophilized lenti-BMP-2 was detected by ELISA method. The expression of Runx-2, OCN, Col1 and OPN in BMSCs was detected by real-time PCR after transfection of lyophilized lenti-BMP-2. SPSS13.0 software package was used for statistical analysis. RESULTS: X-gal staining showed an MOI of 100 pfu/cell, and stable transfection efficiency. Before and after lyophilization, no significant change was observed in regard to the effect of lyophilized lenti-BMP-2 on BMSCs proliferation (P>0.05). ELISA method showed that BMSCs transfected by lyophilized lenti-BMP-2 could express BMP-2 protein continuously and stably at a high level. Before and after lyophilization, the result of real-time PCR showed that no significant difference in the expression of OPN,Col1,OCN and Runx-2 in BMSCs (P>0.05). CONCLUSIONS: Lyophilized lenti-BMP-2 with trehalose can maintain high activity for a long time as an effective and reliable storage method.

[The influence of drilling pulling ways and cooling systems on dental implant surgery].

PURPOSE: To study the effect of different ways of pulling the drilling burs and cooling systems on alveolar bone temperature of the surgical area, and explore the changes of temperature field in dental implants. METHODS: Forty-eight unified standard artificial (nylon) bone blocks were fabricated and divided into 6 groups according to different drilling pulling ways and cooling systems. The changes of bone temperature field were detected in 6 groups, and the highest temperature in temperature field was measured and recorded. The date was analyzed with SPSS 12.0 software package for ANOVA. RESULTS: The temperature in the surgical area using internal cooling systems under the same drilling pulling was lower than using external cooling systems. The temperature in the surgical area using secondary drilling pulling way was lower than using direct drilling methods under the same cooling systems. The temperature in the surgical area using secondary drilling pulling way was the lowest when internal cooling systems was adopted(P<0.05). CONCLUSIONS: Drilling pulling way and internal cooling systems can effectively reduce the temperature in the surgical area, lessen heat production and improve the success rate of dental implants.