Objective:To investigate the biological characteristics of dental epithelial cells derived from cervical-loop epithelium in rat lower incisor. Methods:The apical end of the lower incisor was dissected from two-day-old Sprague-Dawley rats by visual microscopy, and dental epithelial cells were obtained by culture of the apical end explants of the lower incisor. The biological characteristics of dental epithelial cells were determined by morphology and immunocytochemistry fluorescence. Results:Dental epithelial cells emigrated from the cervical loop of rat lower incisor, and epithelium-like morphologies with round-shape or square-shape was observed. Dental epithelial cells had a striking proliferation potential with a high level of BurdU labeling. As a marker of epithelium stem cells, P63 expression was observed in most early cultured cells. However, as cells were subcultured, dental epithelial cells,with the lower level of BurdU labeling,decreasing expression of P63 and increasing expression of alkaline phosphatase, were inclined to terminal differentiation.Conclusion:Stem cells or dental epithelial progenitor cells might reside in the cervical loop of the apical end of the rat lower incisor. The present study may provide an excellent cell source for study on the differentiation of dental epithelial cells and tooth regeneration.

Objective:To understand the roles of PTHrP in the pathogenesis of temporomandibular joint after over mechanical loading. Methods:Fifteen adult New Zealand rabbits were subjected to traction between the mandibular ramus and zygomatic arch in the postero-superior direction unilaterally using elastic force. The rabbits were killed respectively at 2, 4 and 6 weeks and the histologic changes were observed by Hematoxylin & Eosin staining. The expression of PTHrP in the condyle of TMJ was observed by immunohistochemistry. Results:Stronger expression of PTHrP could be found in proliferation cell layers and upper hypertrophy cell layers in the early stage after operation, and weaker expression in mid stage, but stronger near the chondrocyte clusters. Conclusion:It is suggested that PTHrP might relate to the regeneration of condyle cartilage.

BACKGROUND:Low concentration of nicotine promotes the angiogenesis and facilitates the healing of skin wounds. However, the role of low concentration of nicotine on the repair of maxil ofacial soft tissue trauma especial y oral mucosa stil remains unclear
OBJECTIVE:To evaluate the effect of low concentration of nicotine on mucosa defect repair of rat hard palate.
METHODS:A circular soft tissue defect at 3 mm diameter was produced in the centre of hard palate of 65 Wistar rats. After the operation, animals were randomly divided into low concentration of nicotine with gel group, gel group and control group. Rats were sacrificed at 3, 7, 10 and 14 days post-surgery. The wound healing was detected with hematoxylin-eosin staining and the difference of wound healing in different groups was compared with gross observation and image measurement.
RESULTS AND CONCLUSION:There was no significant difference in the wound healing in different groups on day 3 post-surgery. On days 7 and 10, the group of low concentrations of nicotine with gel was faster than gel group and control group (P<0.05);the wounds were completely healed on day 14, with no significant difference among the groups. Low concentrations of nicotine may promote the mucosa defects repair of rat hard palate.

Objective; To investigate the remodeling mechanism of the retrodiscal tissues of temporomandibular joint after mechanical loading. Methods; 15 adult New Zealand rabbits were subjected to traction between the mandibular ramus and zygomatic arch in the postero-superior direction unilaterally using elastic force. The animals were killed respectively at 2, 4 and 6 weeks. The histologic features were observed by Hematoxylin & Eosin and Alcian blue staining. The expressions of aggre can and collagen II antigen in the articular disc of temporomandibular joint were observed by immunohistochemical staining. Results: The articular disc of the traction side in temporomandibular joint was characterized by an early phase (2 weeks postoperatively) with partial anterior disc displacement and disc deformity and subsequently in deposition of fibrous material in the matrix of the retrodiscal tissues. With time going on, fibroblasts significantly decreased and connective tissues increased. A small quantity of cartilage-like cells were also investigated in that area. However, no obvious histological change was observed in the control group. Compared with the control group, glycosaminoglycan, ag-grecan and collagen II were weakly positive in the intermediate zone of articular disc in experimental group. Aggrecan was stronger positive in the intermediate zone of articular disc after two weeks in experimental group. When traction period prolonged, glycosaminoglycan, aggrecan and collagen II were strong positive in the retrodiscal tissue of articular disc in experimental group. Conclusion; These investigations reveal that distracting mandibule towards rear and top through ansa capitis, the synthesis of cartilage matrix increase and a small quantity of cartilage cells appear to adjust to its functions.

Objective:To construct the siRNA expression vector of focal adhesion kinase(FAK) gene and inhibit the expression of FAK gene in tongue cancer cell line Tca8113 by RNA interfering technique. Methods:According to the encoding sequence of FAK mRNA, two pieces of oligonucleotide sequences were designed and synthesized. The annealed oligonucleotide fragments were subcloned into pGCSilencerTM-U6/Neo siRNA expression vector. After being identified by restriction enzyme method, the recombinant pSilencer-FAK plasmids were transfected into Tca8113 cells. The transfected cells were selected by G418 method. Immuocytochemistry and Western blotting were used to evaluate FAK gene silencing efficiency. Results:The oligonucleotide fragments were correctly inserted into pGCSilencerTM-U6/Neo vector. FAK expression of the transfected cells was significantly down-regulated by pSilencer-FAK. Conclusion:The siRNA expression vector of FAK is successfully constructed and FAK expression of Tca8113 cells can be inhibited by RNA interfering technique.

Objective Studies have shown that low concentrations of nicotine can promote neovascularization and promote wound healing.This article aimed to investigate the influence of low concentration collagen membrane slow-release system on the hard palate trauma of rats.Methods Using poly(lactic acid-co-glycolic acid) (PLGA) copolymer as carrier materials, low concentration nicotine sustained-release particles were prepared by emulsion evaporation method (w/o/w), using collagen membrane as the brace and establish a low concentration collagen membrane system.48 Wistar rats were divided into experimental group and blank group, 3 mm diameter circular wound was made in the forepart palate.Low concentration of nicotine collagen membrane sustained-release particle system and blank collagen membrane (control) were sutured on the wound with 6-0 absorbable thread.Then, observed the wound healing of 0, 3, 7, 10 days and compared the healing differences between each groups.Results Under the electron microscope, the nicotine sustained-release particles were circular, similar size with rough surface, the average diameter were 3.0±0.2μm, the encapsulation efficiency and drug loading rate was 50.2% and 4.12% respectively.In vitro, nicotine sustained-release particles released much more nicotine on the first day, less on the second day, tends to stable and fluctuate within a certain range from the third day on, and declined sharply after about 10 days, nicotine concentration from 3rd to 10th day was fluctuate within 10-5-10-4mol/L.Postoperative wound healing, no significant difference in 3 days(P>0.05), after 7 days, the wound healing of experimental group significantly greater compared with the control (P=0.015).The wound was healed in 10 days after operative, there was no significant difference between two groups(P>0.05).The epithelial proliferation in the experimental group was significantly greater than that in the blank group, there were many fibroblasts, inflammatory cells and new capillaries, the epithelial process is short, the submucosa is loose, and a large number of collagen fibers are produced.The lamina propria is closely connected with the periosteum, and the wound is healed Conclusion Low concentration of nicotine sustained-release particles collagen membrane system may promote wound healing in the hard palate mucosa of rats.

Objective:To investigate whether chitosan-polyelectrolyte complex (CS-PEC) can be used as scaffold for chondrocyte culture and for cartilage regeneration in vivo.Methods:Condylar chondrocytes of fetal mouse were seeded onto the three-dimension gel scaffolds of CS-PEC and cultured.The cultured chondrocytes/CS-PEC complex samples were transplanted subcutaneously into nude mice and the CS-PEC scaffold without chondrocyte was used as the control.The animals were sacrificed 4 and 8 weeks after operation respectively.Cartilage formulation was observed by histological and immunohistochemical methods.Results:In the in vitro culture the majority of cells attached to the CS-PEC surface and expanded rapidly. 4 weeks after transplantation,in the chondrocytes/CS-PEC complex the scaffold maintained mostly the original structure. Hypertrophic chondrocytes appeared in scaffold materials. CollagenⅡwas positive in the new cartilage. 8 weeks after transplantation the scaffold degraded almost completely and new cartilage could be observed. CollagenⅡ and cartilage matrix was positive in the new cartilage and the collagen I was positive in the surrounding fibroblast-like cells. In control transplants,8 week after transplantation some fibre-like tissue formed in the circumference, but there was no new cartilage formation and the collagen II and the cartilage matrix was negative.Conclusions:CS-PEC may be used as scaffold for fibre-cartilage regeneration.

[Abstract ] Objective More and more researches demonstrate that epithelial-mesenchymal transition(EMT) is highly rele-vant to cancer metastasis , tissue fibrosis and skin wound healing , but its role in the wound healing of oral mucosa still needs further ex-ploration.This study was designed to discuss the effects of EMT on the wound healing of lingual mucous membrane in rats . Methods A 3mm-diameter circular defect was made on the mucosa of lingual dorsum in 8-week-old Wistar rats.The rats were put to death at day 0, 1, 2, 3, 4 and 8 after operation.We observed tissue healing process by HE staining and used immunohistochemical fluorescence to detect the expressions of EMT-related protein E-cadherin(E-cad), Vimentin and Fibroblast specific proteins (FSP1) in lingual mucous membrane during wound healing . Results The expressions of E-cad at the edge of the wound in the lingual mucous membrane of rats at day 2 and 4 after operation were less than those at day 0 and 1 after operation , while interstitial cell specific protein Vimentin and FSP1 were positively expressed in the epidermal basal layer .The wound of lingual mucous membrane healed completely at day 8 after operation , and E-cad expression was close to that at day 0 after operation .A small amount of Vimentin and FSP 1 expressed in the epi-thelial basal layer . Conclusion E-cad, Vimentin, FSP1 are involved in the wound healing process of lingual mucous membrane . During the wound healing in the tongue mucous membrane of rats , some epithelial cells gain the feature of mesenchymal cells in the process of migration to wound centre .EMT has played an important role during wound healing of lingual mucous membrane in rats .

OBJECTIVEThe aim of this study is to study genotype, transmission, clinical and pathological characteristics, and prognosis of oral condyloma acuminate (CA) in children.

METHODSThe authors retrospected the clinical characteristics and slices of HE staining of six cases which have been diagnosed as oral CA and, performed inmunohistochemistry (IHC) and in situ hybridization (ISH) analysis to detect the DNA of human papilloma virus in 5 cases.

RESULTSOral CA often happened in the hard or soft plates of children of two-year-old. Most of them came from the families had been infected by human papilloma virus (HPV). Histological examination demonstrated that koilocytes were common in the upper spinous and corneal layers. HPV was detected in all cases. HPV16/18-E6 antigen was positive in 4 of 5 cases examined. The result of ISH only show one case was HPV6- and HPV11-positive, and the other case was HPV-positive, but HPV could not be detected when recurring.

CONCLUSIONThe pathogen leading to oral condyloma acuminate (CA) and the transmission way of children may be different from that of adults.

Child, Preschool ; Condylomata Acuminata ; diagnosis ; virology ; DNA, Viral ; analysis ; Female ; Humans ; In Situ Hybridization ; Infant ; Male ; Oncogene Proteins, Viral ; analysis ; Papillomaviridae ; isolation & purification ; Papillomavirus Infections ; diagnosis ; virology ; Recurrence ; Repressor Proteins ; Retrospective Studies ; Stomatitis ; diagnosis ; virology

Objective: To evaluate the effects of sevoflurane on the dose-response relationship and on the timecourse of recovery of rocuronium. Method: Sixty patients,ASA grade Ⅰ,aged 18 to 52 years, undergoing elective plastic surgery,were included in this study. Patients were equally allocated randomly to either the control or the sevoflurane group. Anesthesia was maintained with 60％ N_2O-O_2-thiopental in the control group,and with 1 MAC sevofurane-N_2O-O_2 in the sevoflurane group. The dose-response relationship of rocuronium was established with a cumulative dosing regimen. Result: The dose response curve of rocuronium in the sevoflurane group was shifted to the left. The ED_(50),ED_(90) and ED_95 of rocuronium were decreased by 31％, 27％ and 25％, respectively in sevoflurane group as compared with those of the control group. Following an intravenous administration of rocuronium 400ug/kg,the duration of peak effect,duration of clinical relaxation,recovery index,and the total duration of action in the sevoflurane group were significantly prolonged vs. the control group. Conclusion: Sevoflurane can significantly enhance the neuromuscular blockade effect of rocuronium and prolong its duration of action.