Objective　To studythe degeneration and regeneration of skeletal muscle after denervation.Methods　Denervation was carried out in gastrocnemius muscles in 30 adult BALB/C mice by cutting the sciatic nerve. The gastrocnemius muscles were removed at 1,2,4,8,12,16 weeks after denervation, respectively. Specimens were processed for histological study and immuno- histochemical technique.Results　Muscle fiber atrophy followed by degerneration and regenerationwas observed in the early peri- od of denervation. Fusion of the regenerated muscle cellswith each other followed by degeneration of the cells and growth of fibro- connective tissue were observed in the later stage. The expression of myoglobin and actin decreased in 1~4 weeks after denerva- tion. The postive expression of the proteins was observed in some 8 weeks′cells and in many degenerated 12~14 weeks′muscle cells.Conclusion　Degeneration and regeneration may coexisted in the denervated muscles. The regenerated muscle cells can′t fully develop due to the deficit of nerve regulation and degenerate again. The regenerated muscle cells will melt each other and can′t develop to mature muscle fiber in the later stage.

Objective　The micronucleus test was applied to evaluate the genotoxicity of a new nanocomplex HA-PA66 root filling materialin vitro.Methods　The dulbecco′s modified eagle media(DMEM) extracts of the powder part and the mixture of the new nanomaterial were prepared separately. The V79 cellwas used as the test cell and the mitomycin C(MMC) as the positive control. The MTT assay was employed in our study to evaluate the cytotoxic effect while the number of micronucleus was used as the criteria forthe detection of genotoxocity.Results　TheMTTvalues in test groups and negative groupwere not significantly dif- ferent at different times (P>0.05). The number of micronucleus in test groups (powder group: 6.1±1.1/1 000; complex group: 5.7±0.6/1 000) was similar to the negative control(5.3±0.8/1 000,P>0.05), while theywere significantly different to the positive control(123.9±8/1 000,P<0.05).Conclusion　The newnanocomplexHA-PA66 root fillingmaterial showed no detectable cytotoxic and genotoxic effects in this study and was proved to be biocompatible.

Objective　The purpose of this studywas to establishtransfergeneicTca8113 cell and evaluate the expression of hu- man endostatin (hES) gene in the cell colonein vitro.Methods　To transfect hES gene into Tca8113 cells, lipofectamin was complexed with plasmid encoding hES gene, and blasticidin S antibiotic was adopted to selectTca8113-hES cell clone. Immuno- histochemistry S-P method was adopted to detect the expression of hES in the transfergenic Tca8113 cellin vitro.Results　Trans- fected by hES, the transfergenic Tca8113 cells could grow and proliferate in RPMI-1640 culture medium containing blasticidin S antibiotic. The expression rate of hES reached 100%.Conclusion　hES gene can express in hES-transfected Tca8113 cellin vitro.

Objective　To study the gene expression changes in extracelluar matrix of condylar cartilage following disc anterior displacement of rabbit TMJ.Methods　The right sides of 28 joints in 40 rabbits were subjected to surgical operation of disc dis- placement. The condylar CollagenⅡand Aggrecan mRNA expression were detected byin situhybridization.Results　Collagen II and Aggrecan mRNAmainly expressed in the lower zone of condylar chondrocyte. Aggrecan mRNA decreased faster than colla- gen II following disc displacement, and adjusted to normal later.Conclusion　Anterior disc displacement leads to alteration of ex- tracellurar matrix gene expression in the condylar chondrocyte, which means the start of remodeling.

Objective　To elucidate the functional status of dendritic cells (DC) in the tissue of oral squamous cell carcinoma by analyzing characteristic phenotype of them.Methods　34 specimens from oral squamous cell carcinoma cases primarily treated with surgery were selected as test group.In addition, 30 specimens of normal mucosa from oral mucocele cases were used as con- trol. Distribution of DC expressing CD1a+, HLA-DR+and CD83+in tumortissue and normal mucous membrane was observed by immunohistochemistry. The number of DC expressingthe antigens, which represented the density of DC infiltrating intotissue, was counted by microscope. The density of DC and the rate of DC expressingHLA-DR in oral carcinoma group and controlwere statis- tically compared.Results　There was no CD83+DC in all cases, but CD1a+DC was found in all samples. The density of CD1a+DC in tumortissue was significantly lowerthan that in normal mucous membrane (P<0.05). HLA-DR antigen expressed on the surface of DC in tumoral epithelium of 27-case carcinoma specimens and in normal mucous epithelium of 23 cases. The rate of HLA-DR positive expression of TIDC had no statistic significance between the two groups.Conclusion　The lower density of DC infiltrating in tumor tissue might reflect the microenviromental immunodeficiency of hosts with oral squamous cell carcinoma, and the functional mature of DC might be inhibited by the immunosuppressive action of oral squamous cell carcinoma.

Objective　To explore the correlation between neck lymph node metastasis and matrix metalloproteinase-2 expres- sion at the invasive tumor front of oral squamous cell carcinomas(OSCC).Methods　Immunohistochemistry LsAB technique was used to observe the expression of MMP-2 at the invasive tumor front and center of OSCC, and the correlation between the expres- sion ofMMP-2 in OSCC and neck lymph node metastasiswere respectively analyzed by statistics.Results　The results demonstrat- ed thatMMP-2 existed in all 71 cases, which the expression ofMMP-2 at the OSCC frontwas more significant than that ofMMP-2 at the OSCC center (P<0.01), and related to neck lymph node metastasis (P<0.05).Conclusion　The expression ofMMP- 2 at the OSCC front could be considered as an index of judging the present of neck lymph node metastasis of OSCC.

Objective　To study the effect of nm23-h1 transfection on proliferation characteristics of adnoid carcinoma cell linesin vitroandin vivo.Methods　In vitroACC-M cell lines were incubated after putative anti-metastatic gene nm23-h1 was introduced into the cells with the help of G418 selective incubation base. The ACC-M cells were transplanted into 10 BALB/C nude mices subcutaneously and non-transfected cell lines were taken as control. Immunohisto chemistry and Ki67 antibody were employed to study the proliferation character of cell crawling pieces and paraffin-bedded slice, meanwhile, the solid tumor of both groups were prepared for flow cytometry(FCM).Results　Transfected cells grew slower than non-transfected cells and this trend became more obvious as passages passed on.In vitrothe expression of Ki67 of transfected cells was little stronger than non-trans- fected cells, while the expression of Ki67 in solid slices was almost negative in both groups. Transfected cells presented slower growth than non-transfected cells in the early stage(2 weeks) and 2 weeks later there was no obvious difference in size(P> 0·05). FCMvalue accordedwellwith the result.Conclusion　Introduction of nm23-h1 into the ACC-M cell lines may have tran- sient inhibitory effects on its proliferation.

Objective　To studythe effect of phosphorothioate antisense Bcl-xLoligodeoxynucleotides on apoptosis and thermo- sensitivity of BcaCD885 cells.Methods　After phosphorothioate antisense Bcl-xL oligodeoxynucleotides were tranfected into BcaCD885 cells. The characteristics of apoptotic cellswere evaluated bymorphological observation andTUNELstaining. Apoptotic rate and Bcl-xL protein expression were analyzed with flow cytometry. The influence of phosphorothioate antisense Bcl-xL oligode- oxynucleotides on apoptotic rate of BcaCD885 cells induced by hyperthermiawith 43℃40 minwas also examined through flow cy- tometry.Results　The BcaCD885 cells transfected with phosphorothioate antisense Bcl-xL oligodeoxynucleotides displayed apop- totic morphological features. The Bcl-xL protein expression level of these cells was down-regulated significantly compared with the controlled group (P<0.05). The apoptotic rate of these cells induced by hyperthermia was increased significantly compared with the controlled group (P<0.05).Conclusion　Phosphorothioate antisense Bcl-xL oligodeoxynucleotides can induce apoptosis and improve thermosensitivity of BcaCD885 cells.

Objective　The aim of this studywas to investigate the mechanism(MDR) ofmultidrug resistance(MDR) ofmucoe- pidermoid carcinoma in salivary gland.Methods　40 cases of mucoepidermoid carcinoma in salivary gland were examined the MDR gene product P-glycoprotein using a monoclonal antibody JSB-1. And 10 of themwere also investigated by detecting the ex- pression of GST-π. All the cases had not been accepted any therapy before the samples were collected.Results　①Positive ex- pression of JSB-1 was observed in 27 of the 40 specimens. The positive expressionwas related not onlywith clinical stage, but also with differentiation degree.②The GST-πpositive expressionwas found in 9 of 10 cases. Therewas no significant different between the positive expression of JSB-1 and GST-π.Conclusion　JSB-1 and GST-πplay an important role in MDR of mucoepidermoid carcinoma.

Objective　The purpose of this study was to evaluate the advantages and disadvantages of vascularized free pero- neal flap as a newmethod for reconstruction of oral and maxillofacial defects.Methods　Twenty-one cases received reconstruction of oral and maxillofacial defectswith free vascularized peroneal flaps in our hospitalwere studied retrospectively. All of the relevant data of operation, such as the cause of the defect, design of the flaps, the recipient vessels of the recipient and the complications were investigated.Results　Twenty cases survived, the average size of the vascularized free peroneal flapwas 8·5 cm×5·25 cm. Conclusion　It is safe and reliable to use free peroneal flap to reconstruct the oral maxillofacial defects.

Objective　To analyze the clinical feature and prognosis of primary branchial carcinoma.Methods　The main method of this studywas reviewing the clinical feature, diagnosis, treatment methods and prognosis of 5 patients suffered from pri- mary branchial carcinoma.Results　All of the tumors were excised extensively. All of the patients received radical neck dissec- tion and post-operative radiotherapy. 3 patients had pathologic evident of metastasis in lymph nodes of cervical region. 2 patients died of local recurrence of tumor and metastasis to lung. 1 patient died after post-operative 2 years. 2 patientswere still alive after 5 years′follow-up.Conclusion　Primary branchial carcinoma has the very similar clinical featurewith branchial cyst. The diag- nosis should be considered if painless mass and swollen lymph nodes were found in upper neck region of patients. Rapid frozen pathologic section should be made regularly to make the diagnosis clear. The treatment should include extensive excision of tumor and radical neck dissection to improve the cure rate and survival rate.

Objective　Curved canal preparation is much difficult in root canal therapy(RCT). Step back technique and rou- tine technique are still regularmethods in curved canal preparation. The purpose of this studywas to introduce a newmethod—re- verse flaring technique, and to investigate its preparation efficiency in intermediate-curvature canals.Methods　48 cases of lower first molars RCTwere collected, whichwere firsttreated because of pulpitis or apical periodontitis inWest China College of Stoma- tology, Sichuan University from Nov. 2001 to Aug. 2003, mesial canal curvature was intermediate (30°~60°), determined by Schineider method. Caseswere divided intotwo groups, in reverse flaringtechnique group, canal preparation in 27 caseswere fin- ished by reverse flaring technique, 21 cases by step back technique as control. In working length determination and fitting master cone stages, cases in two groupswhich fit full working lengthwere recorded, determined by radiogragh, and analyzed byχ2test. Results　Inworking length determination stage, caseswhich fit full working length in reverse flaring technique groupwere signifi- cantly more than that of step back technique group (P<0·05), in fittingmaster cone stage, caseswhich fit fullworking length in reverse flaring technique group were also significantly more than that of step back technique group(P<0·05).Conclusion　In working length determination stage, cases which fit full working length in reverse flaring technique group were significantly more than that of step backtechnique group (P<0·05), in fittingmaster cone stage, caseswhich fit fullworking length in reverse flar- ing technique group were also significantly more than that of step back technique group(P<0·05).

Objective　To observe the dynamic changes of oral microflora early colonized in infants.Methods　The oral swab samples forthe studywere taken in 1day, 1, 3, 6, 9, 12 months after birth from 12 healthy neonates. By choosing suitable dilut- ed concentration, the samples were incubated aerobically, facultative anaerobically and anaerobically. The strains were identified by observing colony characteristics, Gram staining and biochemical tests.Results　S.salivariuswas the most frequentmicroflora, followed byS.mitis,S.sanguis,S.gordoniiandS.mutansoccurred in oral cavity after tooth eruption.Veillonella spp. can be detected in oral cavity of 1-month-old babies,A.odontolyticuswas isolated from8.3% infants ofmore than 3 months old.L.aci- dophilusmaintained the lower prevalence in oral cavity of babies.Leptotrichia buccalisandCapnocytophaga spp. occurred in oral cavity of some dentate infants.Conclusion　S.salivariusandS.mitisare predominant species in oral cavity of the infants,Veil- lonella spp. is the first and the most anaerobic species appeared in oral cavity of healthy babies.A.odontolyticusis the first actino- myces detected in oral cavity. With the increasing months, kind and amount of microflora increase dramatically.

Objective　To study the treatment outcome of rhabdomysarcoma(RMS).Methods　74 cases of RMS with defi- nite pathologic diagnosis treated in our department during the past 20 yearswere investigated. The relationship between the therapy and prognosis was analyzed.Results　52 cases among the 74 patients received different surgical treatment and post-operative ra- diotherapy. 22 cases received radiotherapy or chemoradiotherapy without surgical treatment. The survival rates demonstrated great differences depending on the different clinical stages and therapy.Conclusion　The combined therapy including radiotherapy after surgical treatment may increase 5-year survival rate.

Objective　To investigate the feasibility and clinical results of applying poly-DL-lactic acid (PDLLA) biomem- branes in cleft palate repair.Methods　68 cleft palate patients were divided into study group and control group. The traditional surgical method was used to control group to close the soft cleft palate, and the PDLLAbiomembrane was used to study group and implanted into the surgical gap between the periosteum and bone at the hard palate, and fixed with suture. The duration, blood loss at operation, post-operative complication, wound healing and recoverywere recorded and compared to conventional cleft palate repair.Results　Operationswere successfully completed on all 34 patients. Wound healing of soft palate and uvulawas uneventful with no incidence of fistula or dehiscence. The primary healing on tissue defect of hard palate occurred in 29 patients, secondary healing occurred in 3 patients, permanent fistula between the oral cavity and the nasal cavity occurred in only one patients, and 3 patients left over fistula on alveolar process. Compared totraditional cleft palate repair, blood loss and incidence of fistula on alve- olar process were decreased; the average surgical time was 89·25 minutes and was not prolonged; and there was no significant in- crease in post-operative complication.Conclusion　Hard cleft palate repairwith PDLLAbiomembranes is safe, simple and practi- cal with good clinical results and is beneficial to minimize the bad influences towards the development and growth for maxilla of cleft palate patients.

Objective　To analyze the treatment outcome of the two methods of intra-capsular injection of temporomandibular joints, the upper capsule alone and both the upper and lower capsules, for different subtypes of temporomandibular disorders. Methods　Aretrospective cohort studywas designed, based on the outpatients and the datawhichwere obtained fromWest China Stomatological Hospital, SichuanUniversity. SPSS10.0 software was used to analyze the data, whichwere collected before the op- eration and one week after the operation.Results　294 patients were followed up. The group of double capsules injection gained better prospect, not only on the mouth-opening but alsothe pain-cured, especially in two subgroups such as the anterior dislocation of disc without reduction and the osteoarthritis ofTMJ.Conclusion　It seems that the double capsules injection of sodium hyalur- onate forTMD can gain better outcome than the upper capsule injection, but a clinical randomized controlled test and a long-term follow-up study of the two methods are needed to verify this finding.

Objective　The purpose of this study was to investigate the center height of clinical crowns and the difference among individuals, togetherwiththe regularity of the Spee curve inmandible and compensating curve inmaxilla forthe peoplewith normal occlusion in Chengdu area.Methods　The datawere derived from systematically collected people with normal occlusion in Chengdu area, including 36 males and 39 females (ranged from18 to 35 years ). The values of center height of clinical crowns, the depths of Spee curve and curve formed by the center of clinical crowns in mandible were obtained by measurement. After- wards, the distribution of the center height of clinical crowns was analyzed, as well as the depth of curve formed by the center of clinical crowns in mandible and its correlation with depth of Spee.Results　(1) The distribution of the center height of clinical crowns accord with normal distribution and the standard deviation was minor(<0.5 mm); (2)There was no statistical difference between male and female for the center height of clinical crowns;(3)The depth of curve formed by the center of clinical crowns in mandible and the depths of Spee curve showed highly correlation(γ=0.986,P<0.000 1).Conclusion　(1) The difference of the center height in clinical crowns among individualswith normal occlusion in Chengdu areawasminor; (2) Therewas no signifi- cant difference on the center height in clinical crowns between male and female; (3) Provide a recommended bracket placement chart suitable for people of Chengdu area in clinical practice; (4) The brackets of the pre-adjusted appliance should be placed in the center of clinical crowns, despite some adjustment are needed in some special circumstances.

Objective　The purpose of this studywas to clone the soluble form of the mouse BlyS (msBlyS) and insert it into a eukaryotic expression vector pSecTag2B in order to further elucidat the antitumor activity induced by msBlyS expressed by the recombined plasmid pSecTag2B-msBlyS.Methods　Full length cDNA of mouse soluble BlyS (msBlyS ) was amplified by reverse transcription-PCR from total RNA of mouse spleen. The PCR product was ligated directly with linearized vector pCR2.1 supplied inthe TA cloning kit. The recombined plasmid pCR2.1-msBlyS which was selected and identified using blue-white screening method and restriction map analysis and the purified original plasmid pSecTag2B were both cut byHindⅢandEcoRⅠ. The di- gested fragments were extracted and purified from low-melting temperature agarose and ligated by T4DNA ligase. The recombined plasmid pSecTag2B-msBlyS were isolated and identified by restricted endonuclease cutting and Sanger dideoxy DNA sequencing. Results　The sequencing data indicated that inserted msBlyS gene had correct DNA sequence and orientation.Conclusion　Eu- karyotic expression vector pSecTag2B. Expressingmouse BlyS have sucessfully been cloned. Thiswill provide us an opportunity to do further research work on BlyS.

Objective　To study the effect of Para-aminobenzonic acid on cell-surface hydrophobicity ofStreptococcus mutans. Methods　Microbial adhesion to hydrocarbons (MATH) was used to measure the cell-surface hydrophobicity ofStreptococcus mu- tanswhich grew in modified Carlsson mediumwith different dilutions of PABA.Results　The cell-surface hydrophobicity ofStrep- tococcus mutansincreased when Carlsson medium contained low dilution of PABA. But following the increase of PABA, the cell- surface hydrophobicity decreased.Conclusion　Para-aminobenzonic acid could inhibit the adherence ofStreptococcus mutans through changing its cell-surface hydrophobicity.

Objective　This study was to compare the retention of posts fabricated by differentmethods and cementedwith var- ious cements in order to provide a guidance for clinical choice of post fabrication methods and luting cements.Methods　Ninety human maxillary anteriorteethwere sectioned by the cementoenamel junction and post-holeswere prepared. All rootswere embed- ded in the center of plastic cylinders and paralleled with the cylinder. All sampleswere divided into 9 groups randomly and equal- ly. Posts fabricated with different methods were then cemented with different luting cements. Each sample was placed into a spe- cialized jig and mounted on a tensile testing machine with crosshead speed of 5 mm/min. Constant tensile force was applied until the post was dislodged, and the tensile force required to dislodge the cemented post was recorded.Results　The mean retention force of parapost and direct post demonstrated significantly higher than that of indirect post did (P<0·05), but there was no sig- nificant difference between parapost and direct post(P>0·05). The mean retention of parapost cement demonstrated significantly higher than that of ZPC andHY-Bond cement did (P<0·05), but there was no significant difference between ZPC andHY-Bond cement(P>0·05).Conclusion　Different fabrication methods and luting cements significantly affect the retention of posts; and there exists an interaction between different fabricating methods and luting cements.

Objective　To study the expression of p16 and nm23 genes in salivary gland tumors and the relation of P16 and nm23 proteins with tumorigenesis of salivary gland tumors.Methods　Expression of P16 and nm23 proteins was examined by SABC immunohistochemical method in 39 cases of paraffin blocks of normal salivary gland tissues and salivary gland tumors.Re- sults　P16 and nm23 protein positive stainingwere mainly found in the cytoplasm and cytoblast of all salivary gland tissues. Posi- tive rate of P16 protein expressionwas 76·9%(10/13) and 40·9%(9/22) in benign and malignant salivary gland tumors, respec- tively. There was signioficant difference between P16 protein expression of benign and malignant tumors byχ2test (P<0·05). nm23 protein positive stainingwas found in 84·6%(11/13) and 45·5%(10/22) of benign and malignant tumors respectively. The expression of nm23 protein in benign and malignant tumorswas significantly different (P<0·05). There was no correlation of the expression of P16 and nm23 in salivary gland tumors was found (P>0·05).Conclusion　p16 and nm23 genes may play an im- portant role in different sides in salivary gland tumorigenesis and the reduce of the expression of p16 and nm23 genes may contrib- ute to the generation of malignant salivary gland tumors.

Objective　To investigate the association between FcγreceptorⅡAgene polymorphism and susceptibility to chron- ic periodontitis in ChineseHan nationality.Methods　DNAsampleswere collectedwith buccal swabs from63 patientswith severe chronic periodontitis(CP), 103 patients with mild to moderate CP and 80 healthy individuals as control. Polymorphism in Fcγre- ceptorⅡA gene cluster was analyzed with PCR-SSP. The genotype distribution and allele frequency among different groups were compared.Results　It was found that the frequency of FcγRIIA-R/R131 genotype was significantly higher in patients with severe CP (19·05%) compared to that of the healthy controls (P<0·012 5).Conclusion　The FcγRIIA-R/R131 genotype may be one of the contributors for the increased susceptibility to severe CP in Chinese Han nationality.

Objective　The purpose of this study was to evaluate thein vitrocytotoxicity of novel Comfort denture adhesive (Comfort-DA), whichwas developed by the authors, to human oral fibroblasts (HOFs).Methods　Asample of Comfort-DAwas prepared and extracted in culturing medium to prepare the eluate. Then the eluate was diluted by culturing medium to 50% and 75% concentration for the assessment of cytotoxicity by tetrazolium bromide (MTT) colorimetric assay. Wells containing freshme- dium alone were served as control. Cell viability was recorded by optical density after culturing in an atmosphere of 5% CO2and 95% air at 37℃for2, 3 and 4 days, respectively. The viability ofHOF cellswas evaluated byMTTassayto investigate cell pro- liferation. Optical density (OD) was measured by a spectrophotometer at 490 nm. Then evaluating the cytotoxicity grade in test groups according to the means of cell proliferation. ANOVAwas used to test the statistical significance.Results　The statistical analysis of the results ofMTT cytological assay indicated significant difference (P<0·05) in OD (indicate cell viability) between all concentrations of Comfort-DA and the control at all incubation times. The results of cell proliferation percentage also showed that the cytotoxicity grade of tested material only displayed“0~2”.Conclusion　The generally favorablein vitrocytotoxicity of the Comfort-DA formulations indicates that this product may be an efficacious denture adhesive.