ABSTRACT
Objective To investigate the effect of C-erbB-2 shRNA on chemosensitivity of mouse lung adenocarcinoma cells and its mechanism,and to find new therapy method for non-small cell lung cancer,especial lung adenocarcinoma.Methods The mouse lung adenocarcinoma Lewis cells were cultured regularly and divided into non-transfected group, pGPU6/RFP/Neo-shNC group and pGPU6/RFP/Neo-erbB-2 group. The plasmids were synthesized and transfected into Lewis cells in each group by Lipofectamine 2000.The expression levels of C-erbB-2 mRNA and protein in the cells in various groups were tested by RT-PCR and Western blotting method, respectively. The Lewis cells were divided into non- transfected group, pGPU6/RFP/Neo-shNC group, carboplatin group, pGPU6/RFP/Neo-erbB-2 group, pGPU6/RFP/Neo-shNC+carboplatin group and pGPU6/RFP/Neo-erbB-2+ carboplatin group. The apoptotic rates of the cells in each group were detected by flow cytometry;the expression levels of Bcl-2 and Bax proteins in each group were determined by Western blotting method.Results The expression levels of C-erbB-2 mRNA and protein in pGPU6/RFP/Neo-erbB-2 group were lower than those in non-transfected group and pGPU6/RFP/Neo-shNC.The apoptotic rate of the cells in pGPU6/RFP/Neo-erbB-2+carboplatin group was the highest in all of the groups (P<0.01);compared with the others, the expression of Bax protein in pGPU6/RFP/Neo-erbB-2+carboplatin group was increased, while the expression level of Bcl-2 protein was decreased.Conclusion C-erbB-2 shRNA can increase the Lewis cells’sensitivity to carboplatin.The mechanism may be that it can enhance the Lewis cells’apoptosis induced by carboplatin through increasing the expression of Bax protein and decreasing the expression of Bcl-2 protein.
ABSTRACT
Objective Clutching internal fixtor(CIF)loose and the fixed part weakly heal up are often found in orthopedic clinic.In the present paper,biomechanics methods were used to try to explain and analyze these issues,providing a helpful suggestion for the application of CIF in clinic.Method Commerical finite element models(FEM)Program ANSYS was applied to set up the finite element models of orthopedic CIF and bone tissue to analyze and evaluate the biomechanical performances of the NiTi shape memory alloy CIF.Results There is an interaction force between embracing force of CIF and resistant force of bone tissue during the orthopedic clinical treatment.The embracing force along two semi-circular arms of CIF is increasing from the open position and reached the maximum value at the open symmetry position where the deformation of the bone occurred.Conclusion It is the key to choose the force loading position during the practical treatment,as the concentration force is the main force when there is an interactive force between the bone and the CIF.
ABSTRACT
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.