Objective　To construct recombinant plasmid pEGFP-BMP7 and determine its expression in rat bone marrow mes- enchymal stem cells (MSCs)in vitro.Methods　cDNA of target gene was obtained from neonatal rat kidney by RT-PCR. After sequencing the target gene, the cDNAwas subcloned into a eukaryote plasmid pEGFP-N1 by directed cloning and then digested with two restrictive endonucleases to verify the correctiveness of the recombinant plasmid pEGFP-BMP7. Rat bone marrow MSCs were transiently transfected with the pEGFP-BMP7 and transfection efficiency of the Green Fluorescent Protein (GFP) was deter- mined. RT-PCR and immunocytochemical analysiswere also performed to detectthe expression of BMP7 in ratMSCs.Results　A 1 311 bp cDNA fragment was obtained by RT-PCR and sequence analysis showed it matched perfectly with that of rat BMP7 gene except a single nucleotide change at 756 bp from T to A. Digestion of the recombinant plasmid showed two 1·3 kb and 4·7 kb fragments and their size were same as those of BMP7 and pEGFP. This indicated that BMP7 cDNAwas successfully subcloned into pEGFP. Transient transfection showed an efficiency of 33% at day 2 in rat MSCs. After transfection, transcription of BMP7 was detected in MSCs and expression of BMP7 protein was also verified.Conclusion　Recombinant eukaryote plasmid pEGFP-BMP7 was successfully constructed and expressed in rat bone marrowMSCs. This procedure may provide a unique method for stimulation of callus formation in distraction osteogenesis and reconstruction of craniofacial bone defects.

Objective　To evaluate the effect of the pulsed Nd:YAG laser irradiation on the survival rate of human periodontal ligament fibroblast (PDLF) at different power and irradiation time settings, and to compare the morphological change of cells before and after irradiation.Methods　The cells were cultured and placed into the 96-well tissue culture plates. Cells were divided into groups according to the irradiation time (10 s,20 s,40 s,60 s) and the output energy (0·5 W,1·0 W,1·5 W,2·0 W,2·5 W). After the irradiation, the cell numberwere counted and the survival rateswere calculated. The correlation between the survival rate and irradiation time as well as power output was analyzed.Results　No significant reduction of survival rates were found in 10 s group, as well as in 20 s group with 0·5 W, 1.0 W setting·The increase of the power output and increase of the irradiation time caused significant reduction of cell survival rate (P<0·05). The irradiation time was more relevant to this reduction than the power output.Conclusion　It indicates that the laser irradiation may cause damage to PDLF and decrease the cell survival rate. The irradiation time is more related to this effect than the power output.

Objective　To investigate the feasibility of plasmid nm23-h1 transfection on high metastatic potential adnoid cystic carcinoma(ACC-M) cell line mediated by cationic lipid.Methods　ACC-M cell were implanted in the maxillofacial region in each of 40 BALB/c nude mice. After the tumor growth to 1 cm in diameter,0.1 ml Lipofctamine-nm23-h1 plasmid complexwere injected intratumorally in 10 mice, 3 days after the first injection,10 mices injected for twice, 10 mice as plamid-blank control, another 10 mice were injected 0.2 ml complex, 2,3,7days after the injection, the mice were killed and the specimen forHE and immunohistological chemistry study.Results　nm23-h1 expression initiated in the tumor cells 3 days after the complex injection, 7 days later, the expression level increased accompanying with extracellular matrix increase, twice injection and multiple channel injection would gain better nm23-h1 expression than once injection and single-channel injection respectively.Conclusion　Cation- ic lipid mediated nm23-h1 plamid transfecting adnoid cystic carcinoma can gain small range positive expression, but the results give little prospect for further clinical treatment in such a manner.

Objective　To explore the effects of applying force during the different stages of estrous cycle on orthodontic tooth movement of rats, so as to offer an experimental princinple forwomen′s orthodontic treatment.Methods　80 female 3-month-old Wistar rats, which had a stable and five-day estrous cycle, were used. Theywere randomly divided into control groups and load- ing-force groups. Each group was divided again into 4 sub-groups according to the different stages of the estrous cycle. The load- ing-force groups received repeated intermittent orthodontic force forfourtimes seperately duringthe same stage of the estrous cycle. The distance between upper incisor and the first molar on the left was measured. The data were analyzed by One-way ANOVA, S-N-K.Results　Therewere significant variations in the amount of toothmovement amongthe groupswhich received the mechani- cal force duringthe different stages of the estrous cycle (P<0·01). Therewere significant variations in the amount of toothmove- ment between the groups received force during pre-estrus and estrus (P<0·05). There were not significant variations between the groups received force during metestrus and diestrus (P>0·05). The largest amount of tooth movement was in estrus group and smallest in pre-estrus one.Conclusion　The effect of tooth movement depended on which stage of estrous cycle was chosen to be the time of applying orthodontic force.

Objective　To study effective operation method of congenital velopharyngeal insufficiency by reviewing clinical data of 29 patients with pharyngoplasties.Methods　29 patients (9 male and 20 female, ranged from 4 to 25 years old, mean age was 13·5) with congenital velopharyngeal insufficiency were available for this study. All cases received Chinese speech intelligibility test and blowing test before and after the pharyngeal flap surgery.Results　Chinese speech intelligibility of 29 cases who under- went pharyngoplasties was improved from 33·86% to 43·13%, and the blowing time was increased from 4·60 to 17·72 seconds, the degree of abnormal speech was reduced.Conclusion　The pharyngeal flap surgery is an effective method for congenital velo- pharyngeal insufficiency, which reduces hypernasality and increases oral pressure, improves the velopharyngeal function.

Objective　To investigate the association of estrogen receptor(ER) gene polymorphism and primary trigeminal neu- ralgia.Methods　By polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), ER gene polymorphism was analyzed in 20 trigeminal neuralgia(TR) patients and 20 control individuals, and the distribution of ER genotype was com- pared in TR group and control group.Results　Therewas no significant difference in frequencies of allele and genotype in XbaI or PvuII polymorphism or XbaI with PvuII polymorphisms together between TR group and control group (P>0·05). The genotypic distribution of Xx or PpXx in TR group was higher than control group, and it was contrary to xx, ppxx or Ppxx in TR group and control group.Conclusion　XbaI or PvuII polymorphism may be related toTR. Women with PpXx genotype may be a dangerous factor to primary trigeminal neuralgia.

Objective　To study a population of rheumatoid arthritis patients and determine the extent of periodontal disease in these patients, in orderto investigate the relationship between periodontal disease and rheumatoid arthritis.Methods　The experi- mental group was composed of 70 patients with rheumatoid arthritis and the control group consisted of 70 age- and gender-matched individualswithout rheumatoid arthritis. The relationship between periodontal status in rheumatoid arthritis and control groups as well as the relationship between periodontal status and rheumatological findings in patients were analyzed.Results　The percent- age of periodontal disease was statistically significant between experimental and control group (P<0·01). The difference of aver- age number of missing teeth and bleeding on probing in the experimental group and control group were not statistically significant (P>0·05). There were more number of periodontal disease index 5 or 6 in experimental group than in control group (P< 0·05). Rheumatoid arthritis patients with moderate to severe bone loss had deeper degree of morning stiffness, erythrocyte sedi- mentation rate levels and serum C-reactive protein levels than patients with no or mild bone loss.Conclusion　Individuals with rheumatoid arthritis are more likelyto experience periodontal disease compares to healthy subjects. They are also very likelyto suf- fer from moderate to severe periodontitis.