砄bjective: To study the rule of the degradation of HA artificial bone(HAB). Methods: The samples of HAB were immersed in PBS or distilled water (DW),the changes of the shape, weight, compressive strength of the samples and pH value of the immersion solutions were measred at the intervals of 2 or 4 weeks until 28 weeks. Results: At 4 weeks, HAB began to be degraded, 8 weeks later, the speed of the degradation slowed down. From 4 to 12 weeks, the compressive strength decreased rapidly. The pH value of the immersion solutions decreased from 2 to 12 weeks,but increased from 12 to 28 weeks when it was close to the neutral value. Conclusion: HA artificial bone can be degraded in PBS solution, and the degradation can cause noticeable changes of the compressive strength of the material and pH value of the immersion solution.

7;there were 32 b ands in tumor group. ③SDS PAGE showed that the number of protein bands with relative molecular mass of 77 000,50 000-52 000,38 000-30 000 increased in the tumour group. Conclusion: In the saliva of periodontitis indivauals there are more basic proteins,the relative molecular mass of the prot ein in the saliva of patients with tumor is different from that of health contro ls.

Objective To investigate the effect of 17?-Estradiol(E 2)on the proliferation cycle of human mucoepidermoid carcinoma Mc3 cells. Methods Mc3 cells were processed with various concentrations of E 2 for various durations. Then, cell proliferation and cell cycle distribution were examined by MTT assay and flow cytometry; CyclinD1 and P27 Kip1 expressions were assessed with immunohistochemistry. Results After being exposed to E 2 in concentrations of 10 -9,10 -8 or 10 -7mol/L for 5 days, the proliferation of the Mc3 cells was enhanced by 29%,54% and 59% respectively, CyclinD1 expression was increased by 16%,19% and 24%, And P27 Kip1 expression was decreased by 33%,30% and 55%, respectively. Compared with the control group, the number of cells in S phase increased by 11.3%,6.6% and 46.7% after the Mc3 cells were exposed to E 2 in the concentration of 10 -7mol/L for 12h,18h or 24h, and the proliferation index(PI) was also increased by 6.0%,3.6% and 205.0% respectively. Conclusion Physiological concentration of E 2 may promote Mc3 proliferation by increasing the expression of CyclinD1 and decreasing the expression of P27 Kip1, thereby stimulate the growth and development of the tumor.

砄bjective: To establish PTEN gene transfected mucoepidermoid carcinoma cell line. Methods: Wild type PTEN gene was transducted into a highly metastatic mucoepidermoid carcinoma cell line by using lipofectamine. The positively transfected cell clones were selected with puromycin. The expression of PTEN protein in the cells was determined by western blot and immunohistochemical methods. Results: An anti puromycin cell clone was obtained and expanded in culture. Western blot and immunohistochemical staining revealed that the PTEN protien was expressed in the transfected cells. The cells were named M 3SP 2 PTEN. Conclusion: M 3SP 2 PTEN is a cell line expressing exogenous PTEN protein.

砄bjective: To establish an immortalized chondrocyte cell line derived from rabbit mandibular condyle without loss of chondrocyte phenotype. Methods: SV 40 large T antigen gene was conducted into primarily cultured mandibualr condylar chondrocytes (MCCs) of 1-2 week old New Zealand rabbits using an recombinant retroviral vector's transfecting method. After cultured in selective medium containing 400 ?g/ml G418 for 3 weeks, colonies were isolated and expanded for further study. Slot blot analysis was used to detect the transcript of type I and type II collagen of the transgenic cells. Results: One of the positive clones had been maintained for 100 passages for nearly one and half year, without any sign of senescence, and termed immortalized mandibular condylar chondrocyte (IMCC). Transcripts of pro ?1 ( I ) and ?1 ( II ) collagen was observed in IMCCs and MCCs by RNA blot. Conclusion: IMCC is an immortalized chondrocyte cell line derived from rabbit mandibular condyle and might be a good model for studying the biological character of MCC.

?Objective:To study the effects of Docetaxel on the proliferation and metastatic potential of mucoepidermoid carcinoma M 3SP 4 cells in vitro and in vivo . Methods:Inhibitory effects of Docetaxel on the proliferation and metastatic potential of mucoepidermoid carcinoma M 3SP 4 cells were investigated with cell counting,cloning assay flow cytometry, tail vein injection and submandibular gland injection of the cells into nude mice. Results:Docetaxel inhibited M 3SP 4 cells growth in a dose and time dependent way. The IC 30 and IC 50 (with 72 h exposure) of Docetaxel were 0.34 nmol/L and 0.63 nmol/L, respectively; the doubling time(h) of the cells treated with the drug at IC 30 for 7 days and of the control were 32.7 h, 43 h, respectively; the clonogenesity(%) of the control and of the cells treated with Docetaxel ( 0.05 nmol/Lor 0.1 nmol/L)were (29.2?1.4)% and (20.2?0.8)% and (2.8?0.4)%, respectively; the number of metastatic foci on lung surface in the nude mice treated with the drug at 30 mg/kg?week and in the controls were 0 and 11?3.4; the weight(g) of submandibular gland in the two groups were 0.31?0.05 and 1.20?0.23 respectively. Conclusion:Docetaxel may inhibit the proliferation and metastatic potential of mucoepidermoid carcinoma M 3SP 4 cells.

Objective: To establish a metastatic cell line from distant organ metastasis using Mc3 cell line in nude mice. Methods: Tail vein injection of Mc3 cells and cell culture technic were employed to induce metastasis in distant organ . Cell counting and flow cytometry were used to study the cell growth. Karyotype analysis and histopathological observation were used to study the morphological features with light and electron microscopy. Results: Paralized nude mouse was observed in 1 out of 50 experimental nude mice. The cells derived from the spinal cord were cultured and transferred for more than 50 passages. The cells were proved to be of mucoepidermoid carcinoma from human being by the morphology, histopathology and karyotype of the cells. The population doubling time and S-phase cell of the cells were 43 h and 22.7% respectively. The cell line was named Ms. Conclusion: Ms is a metastatic cell line of spinal cord metastasis in nude mouse derived from human mucoepidermoid cacinoma cells.

Objeact:To evaluate the effects of the exogenous PTEN gene on morphology of the highly metastatic mucoepidermoid carcinoma cell line M3SP2. Methods: Morphological observation of vehicle transfected M3SP2-pBp cells and PTEN transfected M3SP2-PTEN cells was performed with inverted microscope, HE staining and optical microscope, scanning electronic microscope and transmisson electronic microscope. Results: Compared with the control cells of M3SP2-pBp, the exogenous PTEN expressing cells M3SP2-PTEN showed morphological changes, such as vacuole denaturalization, shrinkage, less microvillus, chondriosome swelling, lysosome amalgamation, and chromatin agglutination. Conclusion: The exogenous PTEN gene may induce denaturalization, necrosis, and apoptosis of the highly metastatic mucoepidermoid carcinoma cells.

Objective:To evaluate the effect of gtfB specific antisense phosphorothioate-modified oligodeoxyribonucleotides(PS-ODNs) on S.mutans sucrose-dependent adherence.Methods:Antisense oligodeoxyribonucleotide targeted to gtfB sequence 709~726 bp(PS-ODN1) and 3 479~3 497 bp(PS-ODN2) were synthesized.Natural genetic transformation of S.mutans with PS-ODN1 and PS-ODN2 was respectively performed.Adhesion of S.mutans to saliva coated hydroxyapatite was examined by crystal violet staining and destain with absolute ethanol.The absorbance at 620 nm was measured by plate reader(the absorbance value derived from the wells without sucrose was used as background and was subtracted).Results:The adhesion ability of the strains treated with antisense PS-ODN was significantly lower than that of the control(P

0.05).Conclusion:Secnidazole is effective and safe in the treatment of pericoronitis.