Objective To investigate the stress in the periodontal tissues using three-dimansional finite element method when Richtts Arch was used.Methods Three-dimensional finite element models of the lower left central incisor and first molar were set up by means of CT.Stress distribution in root,PDL and alveolar bone,and the tendency of the tooth movement were obtained by calculation under Richtts Arch.Results The value of the force at the left lower incisor was -0.34 Newton and the value of the force at the left lower molar was 0.65 Newton.The molar model revealed that the tensile stress concentration was at the mesial root cervix and the compressive stress was at the distal root cervix.The incisor model showed that the tensile stress was concentrated at the lingual cervix and the compressive stress was concentrated at the apical tip.The arch wire exerted intruding force,lingual force and the incisor tended to lingual movement and intruding movement.The molar had the tendency of lingual movement and distal tipping movement.Conclusion The anchorage molar will incline mesially when Richtts Arch is used in treatment of deep overbite,the additional torque must be used in the anchorage molar.

Objective To observe the effects of human EP cells (hEPCs)transplantation on the function recovery of rats with spinal cord injury.Methods 24 SD rats (5 ones died in the process of operation)were firstly completed transection of T10 segment of spinal cord by using quick knife slices to complete animal model.19 rats after spinal cord transection were randomly divided into:the experimental group (10 cases)and the control group (9 cases). The experimental group with spinal cord injury was injected 7.5μL suspension of hEPCs (human Endothelial Progeni-tor Cells).Adjacent area of spinal cord injury in control group was injected equal amount DMEM(Dulbecco minimum essential medium.Postoperative intraperitoneal injection of cyclosporine A,an immunosuppressant,was administrated daily.At postoperative 1,2,4,6,8 weeks Basso Beatlie Bresnahan (BBB)score were administrated to record the neural function recovery of lower limbs in SCI rats.The transection spinal cord were removed from rats 8 weeks after operation to detect transplanted survival hEPCs in transection spinal cord of ratsby immunohistochemical and hybridization technique. Results 2 weeks after SCI model established,the BBB scores in the experimental group and the control group showed no statistically significant difference(t =0.61,0.69,all P >0.05).4 weeks postoperatively,the BBB score of the experimental group (1.67 -0.71)points was more than that in the control group (1.11 -0.60),the difference was statistically significant(t =3.16,P <0.05).Untill 8 weeks scores were respectively the (4.00 -1.41)of the experimental group and the (1.44 -0.89)of the control group,the difference was statistically significant(t =5.384,P <0.05). Finally it was concluded that 4,6,8 weeks after SCI,hind limbs function of the experimental group was significantly better than that of the control group,the difference had statistical significance (P <0.05).Hybridization and immuno-histochemical detection showed that the transplanted hEPCs not only live in the host but in partial hEPCs chimeric to SCI in rats of spinal cord and its vascular system.Conclusion After transplantation,hEPCs can survive,differentiate into vascular endothelial cell,and improvement spinal cord function recovery as compared with control group.

BACKGROUND:Studies have shown that human cartilage glycoprotein-39 has a certain relationship to articular cartilage degeneration and repair, but the mechanism of action is not very clear. OBJECTIVE:To investigate the effect of human cartilage glycoprotein-39 on chondrogenesis of precartilaginous stem cels. METHODS: Precartilaginous stem cels were isolated from the adult articular cartilage. Cels which could express CD105 and CD166 were detected using flow cytometry folowed by isolation and purification. Isolated precartilaginous stem cels werecultured using monolayer method, and then, passage 2 cels were cultured in the medium containing human cartilage glycoprotein-39 and normal chondrogenic medium for 14 days, respectively. Immunohistochemical staining was used to observe expression of type II colagen and gross observation was done for evaluation of cartilage formation. RESULTS AND CONCLUSION:The precartilaginous stem cels isolated from the adult articular cartilage could express CD105 and CD166. After induction, differentiated precartilaginous stem cels gradualy gathered and formed nudes. The induced cels were positive for type II colagen; after induction by human cartilage glycoprotein-39, the nodules became larger and the expression of type II colagen was increased. These findings indicate that precartilaginous stem cels with chondrogenic ability can be isolated from the adult articular cartilage, and can be induced to differentiate into chondrocytes, in which human cartilage glycoprotein-39 plays an important role.