BACKGROUND:Intertrochanteric fracture is one of the common fracture, and accompanied by osteoporosis and high energy injury. The fracture line often descended, and induced A3 intertrochanteric fracture. This type of fracture is difficult to treat. Common intramedulary fixation includes proximal femoral nail anti-rotation and InterTan, which have high stability, are minimaly invasive, and have been extensively used. OBJECTIVE: To compare the biomechanical stability of A3 intertrochanteric fracture fixed with proximal femoral nail anti-rotation and InterTan by finite element analysis. METHODS:Three three-dimensional finite element models of the AO3.1, AO3.2 and AO3.3 intertrochanteric fracture fixed with proximal femoral nail anti-rotation and InterTan were established. Fixation was completed according to the requirement of Department of Orthopedics. Stress distribution of femur and fixator of different models was observed. Stress peak at different areas was compared in femur and fixation models. Biomechanical stability was analyzed. RESULTS AND CONCLUSION: The maximum pressure concentration area in AO3.1 intertrochanteric fracture with proximal femoral nail anti-rotation was located in the lateral proximal femur, and with Intertan was located in the medial proximal femur. The AO3.2 had little differences between two types of nails. The AO3.3 intertrochanteric fracture with proximal femoral nail anti-rotation was located in the medial proximal femur and the medial distal implant. There was no significant pressure concentration with InterTan. The von Mises pressure of six models was concentrated in the medial distal implant, and higher maximum von Mises pressure was found in the proximal femoral nail anti-rotation. There was significant difference of von Mises distribution between the lateral and medial implant with proximal femoral nail anti-rotation. Except the AO3.3 intertrochanteric fracture with proximal femoral nail anti-rotation, the maximum pressures of remaining models were located in the main nail and interlocking nail infal. These results concluded that the fracture fixed with InterTan exhibited fine fixation stability in the AO3.1 and AO3.3 intertrochanteric fracture. There was no significant difference of fixation stability between proximal femoral nail anti-rotation and InterTan in AO3.2. The von Mises distribution of InterTan for intertrochanteric fracture is more reasonable.

Objective To explore the construction method and physicochemical properties of disulfide?bonded hyaluronic acid?functionalized sodium?meter probe for hepatocellular carcinoma, and its biological evaluation in vitro and feasibility of MRI. Methods Synthesis of hyaluronic acid?disulfide?bonded?poly ε?caprolactone (HA?SS?PCL) by disulfide?bonded alkynyl?terminated polycaprolacton (alkyne?SS?PCL) and azido?terminated hyaluronic acid (HA?N3) by clicking chemical reaction, then doxorubicin (DOX) and superparamagnetic iron oxide (SPIO) were encapsulated in HA?SS?PCL core by dialysis method.HA?SS?PCL@DOX/SPIO was prepared and its particle size,DOX and SPIO loading rate were measured. With PBS as control group, the safety of HA?SS?PCL on human hepatocellular carcinoma cells HepG2 and normal liver cells LO2 was evaluated by the methylthiazolyl tetrazolium (MTT) assay, and the cytotoxicity of HA?PCL@DOX/SPIO and HA?SS?PCL@DOX/SPIO on human hepatocellular carcinoma cells HepG2 was evaluated. Immunofluorescence and flow cytometry were used to observe the expression of CD44 receptor on the surface of HepG2 cells in HA?PCL@DOX/SPIO and HA?SS?PCL@DOX/SPIO groups. Through in vitro MRI, PBS was used as the control group to observe the changes of T2 signal intensity of HA?PCL@DOX/SPIO and HA?SS?PCL@DOX/SPIO groups when SPIO concentration was 10, 20, 40, 80 μg / ml. One way ANOVA test and t test were used. Results HA?SS?PCL@DOX / SPIO sodium?meter probes were successfully constructed. The particle size of HA?SS?PCL@DOX/SPIO was (126.9±6.3) nm,and they were spherical with uniform size. The loading rates of DOX and SPIO were 61.4% and 58.7%. MTT assay showed that the survival rate of HepG2 and LO2 cells was more than 80% even at 500 μg/ml of HA?SS?PCL, 66.6% in HA?PCL@DOX/SPIO group and 55.2% in HA?SS?PCL@DOX/SPIO group. Immunofluorescence and flow cytometry showed that HA?PCL@DOX/SPIO and HA?SS?PCL@DOX/SPIO groups all have strong fluorescence, and the latter has stronger fluorescence intensity the former fluorescence intensity was 139.70±8.52,less than the latter 245.06±13.21. In vitro MRI showed that the T2 signal intensity of HA?PCL@DOX/SPIO and HA?SS?PCL@DOX/SPIO was significantly lower than that of the control group (F values were 613.591 and 569.234,P=0.000), the latter decline rate was more significant. Conclusion The disulfide?bonded hyaluronic acid?functionalized sodium?meter probe for hepatocellular carcinoma has excellent physicochemical properties, good targeting and MRI functions on human hepatoma cell HepG2 at the cellular level in vitro.

Objective To preliminarily explore the anti?cancer efficiency of disulfide?bonded hyaluronic acid?functionalized targeted sodium?meter probe for hepatocellular carcinoma and the feasibility of MRI. Methods Twenty?one nude mice models of subcutaneous liver cancer transplantation were randomly divided into saline, hyaluronic acid?poly ε?caprolactone@ doxorubicin/superparamagnetic iron oxide (HA?PCL@DOX/SPIO) and HA?disulfide?bonded?PCL@DOX/SPIO (HA?SS?PCL@DOX/SPIO) groups, with 7 mice in each group. The experimental groups were injected with micelles at a dose of Fe 5 mg/kg through the tail vein, and the control group was injected with the same amount of saline via the tail vein. MRI was performed before and after injection (2 h, 4 h, 8 h). The T2 value of the region of interest (tumor) was measured and its decline rate was calculated. Twenty?one nude mice models of orthotopic liver cancer transplantation were randomly divided into saline group,HA?PCL@DOX/SPIO and HA?SS?PCL@DOX/SPIO groups, with 7 mice in each group. The experimental groups were injected with micelles at a dose of DOX 2 mg/kg through the tail vein by three consecutive times a day apart, and the control group was injected with the same amount of saline through the tail vein. Continuous observation for 15 days to calculate tumor inhibition rate. One way ANOVA test was used. Results The T2 value of HA?SS?PCL@DOX/SPIO group decreased significantly after 2, 4 and 8 hours (P<0.05) than initial time, which was distinct compared with HA?PCL@DOX/SPIO group. The growth rate of tumor in HA?SS?PCL@DOX/SPIO and HA?PCL@DOX/SPIO groups was significantly lower than that in the control group (F=21.513,P<0.05). The former had the most obvious inhibitory effect on orthotopic liver cancer (47.7% and 28.2%). Conclusion Disulfide?bonded hyaluronic acid?functionalized targeted sodium?meter probe for hepatocellular carcinoma(HA?SS?PCL@DOX/SPIO) has high anti?cancer efficiency and imaging function at the animal level in vivo, and can be used to monitor the early therapeutic effect of tumor at the molecular imaging level.