By using three-dimensional finite element analysis method, the necessity of tail joints in the establishment of finite model specifically for the widely used tail-suspended rat experiments in weightlessness simulation was explored. A weightlessness tail-suspended three-dimensional finite element rat model was established using CT scan and Abaqus software, and the computation and analysis were conducted using the same model. The stress distribution and displacement in tail, lumbar spine, pelvis and femur of a tail-suspended rat both with and without cartilage were simulated and calculated.The results showed that stress distribution and displacement of tail-suspended rat were quite different between rats with cartilage and without cartilage, which affected the calculation precision of the model. Accordingly the consideration of articular cartilage in establishing the tail-suspended three-dimension finite element rat model is quite necessary,In addition, the asymmetry of pelvis stress distribution of tail-suspended rat suggests that the degree of balance of tail-suspended rat will affect the stress distribution in rats.

[Objective]To examine the difference of proliferation and ?-smooth muscle actin(?-SMA) expression between healing and normal medial collateral ligament(MCL) fibroblasts.[Method]Ten adult,male,Sprague-Dawley rats weighing between 350 and 375 g were used in this study.Normal and healing MCL were cut into small pieces in aseptic conditions,and then placed and cultured in culture chamber.Fibroblasts were passaged with 0.25% trypsin.After 24 and 48 hours incubation,MTT was used to measure the cell proliferation.The production of ?-SMA was measured by Western Blot.[Result]After 24 and 48 hours incubation,healing fib roblasts showed absorbency values of 0.49?0.080 and 0.53?0.07 respectively.II was found that healing fibroblasts proliferated faster than normal fibroblasts(P

[Objective]To examine the effects of TGF-?1 on the production of ?-SMA and extracellular matrix in flexor tendon sheath fibroblasts. [Methods]Sheath fibroblasts were obtained from rabbit flexor tendons.Cell culture was supplemented with 5ng/ml of TGF-?1.After 48 hours incubation,the production of a-SMA was assayed by Western-Blot.The productions of collagen I and fibronectin in supernatants culture were examined using ELISA.[Results]Treatment with TGF-?1 significantly stimulated a-SMA production in flexor tendon sheath fibroblasts (P

Objective To provide theoretical basis for clinical treatment of all-ceramic crown prosthodontics,the influence of cement thickness on the stress distribution in all-ceramic crowns under load was studied numerically.Methods The finite element analysis(FEA) model of a standard mandibular first molar was established using spiral CT and CAD software,and then it was applied to analyze the stress distribution of all-ceramic crowns under vertical loading using FEA software.Results Stress concentration was found in mesial and distal cement;the stress distribution at the cement upper and lower interface was found to be similar,and the stress magnitude discrepancy between the two interfaces was small;the stress of the model with 0.15 mm cement in the cervix was lower about 30% than the one of the 0.05 mm model.Conclusions The cement thickness plays an important role in the stress distribution of all-ceramic restoration system.The model with 0.15 mm cement shows a better resistance to destruction among the three models investigated.

Objective To study the stability of micro-implant orthodontic anchorage(MA)with different pitch in the case of immediate loading.Method Employing 3D finite element analysis method,the stress and dis-placement distribution on the bone interface of MIA with different pitch(0.3 mm、0.5 mm、0.7 mm and 1.0 mm,respectively),which was 1.47 N loaded vertically in the major axis direction,were analyzed.Result The pitch affected the stress distribution significantly,because the maximum stress increased with the pitch decreasing and the impact of pitch on stress distribution on neck and central locations of MIA were different;to decrease the pitch could reduce the max displacement of the jaw,but the impact of pitch on displacement distribution of MIA was not significant.Condusions In the case of immediate loading.MIA with pitch 0.5 mm-0.7 mm is suggested to be selected as orthodontic anchorage in the clinic.

BACKGROUND:Currently, there are large numbers of studies related to the association between colagen type I alpha1 (COL1A1) Sp1 polymorphism and bone mineral density and fracture risk, but the results are inconsistent. OBJECTIVE:To evaluate the impact of the COL1A1 Sp1 polymorphism on bone mineral density and fracture by using the Meta-analysis. METHODS:We comprehensively searched the eligible studies for the present meta-analysis through MEDLINE, PubMed, EMBASE databases. Pooled odds ratios and 95% confidence intervals of Sp1 polymorphisms for bone mineral density and fracture risk were obtained, with attention to study quality and publication bias. RESULTS AND CONCLUSION:A total of 32 studies met the inclusion criteria, among which, 22 studies evaluated the Sp1 polymorphism and fracture risk. Significant associations were found in five genetic models. In the stratified analysis by region, the same results were found in the Europeans but not Americans and Asians. Thirteen studies evaluated the Sp1 polymorphism and low bone mineral density risk. A similar result was obtained. However, the analysis of bone mineral density data showed an increased relation between Sp1 polymorphism and low bone mineral density in Europeans and Americans but not in Asians. Overal, the current meta-analysis concludes that the COL1A1 Sp1 polymorphism is associated with low bone mineral density and fracture risk, especialy in Europeans. However, susceptibility to them varies markedly among populations from different regions.

Objective To investigate the value of X-ray Knife in the stereotaxis radiotherapy of lung cancer.Methods 52 cases with pulmonary carcinoma were treated with X-ray knife,before and after that,general radiotherapy was applied.After whole radiotherapy,2 or 3 months later,all patients were followed by CT scan.The changes of tumor and clinical appearances were compared before and after therapy.The curative effect was estimated according to clinical appearances and CT findings.Results 6 patients were complete response(11.5%) ,29 patients were partial response(55.8%) and 13 patients were no changes or reduced less than 50%.The total responsive rate was 92.3%.Conclusion The treatment of lung cancer with X-ray Knife can give tumor accuracy high dosage irradiation.The short term therapeutic effectiveness is significant and safe on clinical.

Objective To examine the effectiveness of HGF in blocking TGF-β1 induced α-SMA and extracellular matrix production in fibroblasts of the flexor tendon sheath. Methods Seven adult male New Zealand white rabbits (3.75-4.00 kg) were used for this study. Both of their front feet were sterilised and the middle digit flexor digitorum profundus tendon equivalents were identified and isolated. These specimens were used to establish primary cell cultures. Sheath fibroblasts were obtained from rabbit flexor tendons. After the cells reached confluence, cells were detached with trypsin/ethylenediamine tetra-acetic acid. All experiments were performed using the cells at the third passage. At 70% confluence the medium was supplemented with 5 ng/ml of TGF-β1 along with increasing doses of HGF (10-40 ng/ml). After 72 hours incubation, the productions of α-SMA were assayed by Western-Blot. The productions of collagen Ⅰ and fibronectin in supernatants culture were examined using ELISA. Results Evaluation of protein expression revealed that TGF-β1 markedly induced α-SMA expression in cultured rabbit flexor tendon sheath fibroblasts. TGF-β1 treated fibroblasts expressed 1.8-fold more protein compared to non-treated fibroblasts (P ＜ 0.05). However, simultaneous incubation of HGF significantly abrogated TGF-β1 induced α-SMA expression in a dose-dependent manner (P＜ 0.05). Treatment with TGF-β1 significantly stimulated collagen Ⅰ and fibronectin production in flexor tendon sheath fibroblasts (P ＜ 0.01). Remarkably, the addition of HGF reduced productions of all components induced by TGF-β1 in a dose-dependent manner (P ＜ 0.05). Conclusion HGF antagonizes TGF-β1 induced α-SMA, collagen Ⅰ, and fibronectin production in flexor tendon sheath fibroblasts. The findings provide a cellular and molecular basis for HGF's acting as a therapeutic agent for adhesions in flexor tendons.

In this study, a 3D model of a transtibial monolimb and residual limb was constructed. The stresses on all nodes of the model under the simulus of the load at the Mid-Stance were computed through 3D finite element analysis (FEA). The stress distribution on the internal and external surfaces of the model was obtained. The results indicate that the stresses on socket are lower than those on prosthetic shank; high stress regions are located on the underneath of prosthetic shank and the border section of socket and prosthetic shank. These data will be useful for CAD\CAM system of monolimb designing.
Artificial Limbs ; Finite Element Analysis ; Stress, Mechanical

AIM: Humanized-NOD/SCID(hu-NOD/SCID) mouse model was established and the level of immune reconstitution was assessed in this model. METHODS: Mononuclear cells (MNC) and CD34+ cells were isolated or sorted from cord blood(CB). Human CD45, CD19, CD3 markers on cells from NOD/SCID murine peripheral blood(PB), bone marrow(BM), thymus were detected by FCM from 4 to 10 weeks after hematopoietic stem cell transplantation. After 10 weeks, the gene expressions of the human ?2M and RAG2 were detected by RT-PCR in PB or bone marrow of mice model. RESULTS: Human CD45, CD19, CD3 cells populations in PB and BM were found by flow cytometry in mice model transplanted with CD34+ cells or CB MNC from 4 to 10 weeks. The highest positivity of human lymphocytes was at 8 week after transplantation. The levels of human cell engraftment in mice transplanted with CD34+ cells were higher than those in mice transplanted with CB MNC. The mRNA of human ?2M and RAG2 were found by RT-PCR in BM.CONCLUSION: The higher level of human lymphocyte engraftment is established in NOD/SCID mouse model transplanted with CD34+ compared with CB MNC. The maturation of T lymphocytes could be happened in bone marrow of mice model.