?Objective: To study the stress distribution of one segment type mono dowel implant with various length and diameter in alveolar bone. Methods: The thickness of cortical bone is 1～2 mm, implant was in close contact with alveolar bone directly. Implants with root length of 10,12,13 and 14 mm, cast diameter of 3.6, 3.7, 3.8, 3.9 and 4.0 mm, corona tall 4 and 9 mm were put into a bone model with alveolar bone. 200 N force was loaded in vertical, 45? oblique and 45? oblique of non center. CT and 3D FEM were used to study the stress distribution and selected the morphology of alveolar bone from first molar of lower jaw and an incisor of maxillary. Results: There was an area of stress in the boundary of the cortical and cancellous bony tissue,horizontal hole. The main region of stress was at the cancellous. Thickness and shape of alveolar bone could affect the distribution of stress. The maximal Von Mises Stress was always in the boundary of cortical and bone that contacted with implant. Higher elastic modulus of bone around the implant had higher stress in cortical stress . Conclusion: The stress of cortical and cancellous bone can be depressed to rise elastic modulus of implant.

Objective To investigate the morphology and the distributon of thymus dendritic cells (TDCs) in mouse. Methods TDCs in mouse were observed and analyzed by the electron microscopy and the immunohistochemistry with DCs marker (including CD205, CD1a and MIDC 8). Results There were the most TDCs in the boundary area of thymus cortex and medulla, lesser TDCs in the cortex, and the least in the medulla. TDCs made up to 2 per cent of all cells in thymus. On TDCs surface there were many processes which extended into diastema surrounding lymphocytes. The nucleus was irregular in shape and there were intentations. The cytoplasm was electron lucent and there were few organelles without any lysosme. Conclusion It may effectively count TDCs and display their morphological character that TDC be jointly labeled by the diversiform markers and its ultrastructure observed.

AIM: To study forms of cell death following cerebral ischemia/reperfusion in diabetic rats. METHODS: Based on the modles of diabetes and middle cerebral artery occlusion(MCAO), characteristics of cell death after ischemia/reperfusion were evaluated synthetically by the pathological, flow cytometry(FCM), TUNEL and the DNA agarose electrophoresis.RESULTS: The occurrence of cerebral injury after ischemia/reperfusion were accompanied by cell necrosis and cell apoptosis. And cell apoptosis was mainly located in ischeamic penumbra(IP) zone around the densely ischemic focus. Ischemic centre(IC)was characterized by cell necrosis. At the same time, the results showed that the process of ischemic cerebral injury worsen by diabetes mellitus was related to inducing cell apoptosis in IP and Mid zone.CONCLUSION: Neuronal damage following focal cerebral ischemia/reperfusion included cell necrosis and apoptosis, IC zone was mainly characterized by the former, however IP zone by the latter, and there had close internal relationship between them. Brain damage following cerebral ischemia/reperfusion was worsen instinctly under diabetic condition.

Objective To study the molecular mechanism of apoptosis of cells in egg granuloma induced by anti-idiotypic antibody NP30 of Schistosoma japonicum.Methods BALB/c mice were randomly divided into two groups. The mice of the experimental group were immunized by injecting NP30 intraperitoneally for three times, while the mice of control group were injected normal saline intraperitoneally. The mice were sacrificed respectively on the 39th, 49th, 64th, 108th, 112nd day after challenge with schistosome cercariae. The expressions of apoptosis-related gene Bax, Bcl-2, death receptor Fas, FasL (Fas ligand) and c-Fos were examined by the S-P method of immunohistochemistry,and Bax, mRNA and Fas mRNA investigated by the in-situ hybridization. Results The expressions of Bax, Fas, FasL and c-Fos were positive in granuloma cells of both groups. The expressions of Bax and FasL in experimental group were higher than those in control group (P