Objective:To observe influence of up‐regulated expression of myocardial heat shock protein (HSP) 70 in‐duced by heat stress on myocardial calcium‐activated potassium channel (KCa ) 3.1 expression in rabbits with atrial fibrillation (AF) caused by rapid atrial pacing (RAP) .Methods :A total of 24 New Zealand white rabbits were ran‐domly divided into sham operation group (n=8 ,only implant electrode without pacing ) ,pacing group (n=8 ,right atrium (RA) received RAP at 600 times/min for 6h) and heat stress pacing group (heat stress group ,n=8 ,received heat stress preconditioning ,then the same RAP as pacing group ) .Results:Compared with sham operation group and pacing group ,there were significant up‐regulation of HSP70 mRNA and protein expression in different sites of heart [HSP70 protein ,left atrium (LA):(39.00 ± 3.21) vs .(39.75 ± 2.82) vs .(69.75 ± 3.45) ,RA: (38.38 ± 2.92) vs .(39.50 ± 3.89) vs .(69.00 ± 2.93) ,left atrial appendage (LAA):(37.75 ± 3.28) vs .(39.00 ± 3.89) vs . (68.63 ± 3.23) ,right atrial appendage (RAA): (37.00 ± 3.85) vs .(38.38 ± 3.74) vs .(68.75 ± 2.82)] in heat stress group , P<0. 01 all ,but there were no significant difference between pacing group and sham operation group , P>0.05 ;compared with pacing group with down‐regulation of KCa3.1 mRNA and protein expressions ,there were significant up‐regulation of KCa3.1 mRNA and protein expressions in different sites of heart [KCa3.1 protein ,LA:(21.25 ± 1.67) vs .(24.00 ± 2.62) ,RA :(21.13 ± 1.96) vs .(23.75 ± 1.83) ,LAA :(21.00 ± 2.07) vs .(23.75 ± 1.67) ,RAA:(20.88 ± 2.03) vs .(23.50 ± 2.45)] in heat stress group ,P<0.05 all ,and there were no significant difference between heat stress group and sham operation group , P>0. 05. Conclusion:Heat stress may induce up‐regulated expression of myocardial HSP 70 of myocardium ,and HSP 70 may inhibit down‐regulation of KCa 3. 1 mR‐NA and protein expressions in rabbits with atrial fibrillation.

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 influence of thrombus aspiration combined bivalirudin during emergency PCI on my- ocardial tissue perfusion and clinical prognosis in patients with acute ST elevation myocardial infarction (STEMI). Methods:A total of 102 patients with acute STEMI,who were confirmed with thrombus burden by CAG in our hos- pital from Jan 2012 to Jun 2014,were selected.According to random number table,they were randomly divided into thrombus aspiration + bivalirudin group (n=52,thrombus aspiration group)and heparin group (n=50,routine PCI group).TIMI blood flow grade 3 rate,TIMI myocardial perfusion grade (TMPG)after PCI,ST segment re- gression rate 2h after PCI,peak value and peak time of cTnI after PCI,LVEF,LVEDd,incidence rates of bleeding and major adverse cardiovascular events (MACE)on one week and one month after PCI were compared between two groups.Results:Compared with routine PCI group,there were significant rise in postoperative TMPG grade 3 rate (56.00% vs.88.46%),TIMI grade 3 rate (58.00% vs.88.46%)and ST segment regression rate (52.00% vs. 76.92%)in thrombus aspiration group,P<0.05 or <0.01. Compared with routine PCI group one month after PCI,there was significant rise in LVEF [(53.76±5.24)% vs.(57.95±5.51)%],and significant reductions in LVEDd [(53.70±3.39)mm vs.(50.63±1.24)mm],peak value [(16.00±4.28)μg/L vs.(13.81±4.00)μg/L]and peak time [(14.00±2.80)h vs.(13.00±2.23)h]of cTnI in thrombus aspiration group,P<0.05 or <0.01. Incidence rate of mild bleeding in thrombus aspiration group was significantly lower than that of routine PCI group (1.9% vs.16.0%),P<0.05,but there was no significant difference in incidence rate of MACE between two groups,P>0.05. Conclusion:Thrombus aspiration combined bivalirudin during emergency PCI is safe and fea- sible for acute STEMI patients,it can effectively reduce incidence rate of bleeding,remove coronary thrombus,im- prove myocardial tissue perfusion and doesn't increase incidence rate of MACE.