Objective To evaluate the difference of myocardium strain between myocadial infarction and ventricular aneurysm (VA) by two-dimensional speckle-tracking imaging in rabbits.Methods 26 healthy New Zealand white rabbits were enrolled in this study,6 were put into the control group and 20 in the experimental group.models of myocardial infarction concomitant with VA were prepared by the ligation of the middle segment of left anterior descending artery and left circumflex artery.At 4 weeks after the procedure,according to the pathological inspect and echocardiography for whether VA formed,the experimental animals were divided into the VA group and the myocadial infarction group.Echocardiography was performed to measure the LV cavity size and cardiac function.Radial strain rate (SrR) and circumferential strain rate(SrC) indexes were measured by 2D-STI software for each animal at the level of apex in left ventricular short-axis view,and then calculated the strain rate decrease percentage in each segment.Results 1)Compared with the control group,SrR-S,SrR-E,SrR A,SrC-S,SrC-E,SrC-A in all segments were reduced significantly in the VA group and the myocadial infarction group (P ＜ 0.05),the VA group was the most significant.2)Compared with the myocadial infarction group,the strain rate decrease percentage of SrR-S,SrR-E,SrR-A,SrC-S,SrC-E,SrC-A in all segment had significant in the VA group.Comparison between the each section,the strain rate decrease percentage of SrR-Santerior wall,SrR-Sateral wall,SrC-Santerior wall,SrC-Slateral wall were the most significant.3)There were the tighter relationship between the strain rate decrease percentage of SrR-Santerior wall,SrC-Santerior wall,SrR-Slateral wall,SrC-Slateral wall and left ventricular ejection fraction (r =0.82,0.72,0.75,0.71,repectively,all P ＜ 0.05).4) The ROC curve analysis showed that when the strain rate decrease percentage was 60％ as the critical point,the strain rate decrease percentage of SrC-Santerior wall,SrC-Slateral wall,SrR-Santerior wall,SrR-Slateral wall had a sensitivity of 83.30 ％,84.40％,83.30％,67.70％％ and a specificity was 73.60％,78.20％％,69.70％,83.30％ for prognosis ventricular aneurysm,repectively.Conclusions After ventricular aneurysm formation,anterior and lateral wall myocardial strain were give priority to the myocardial mechanics reconstruction,thus systolic myocardial strain rate decrease percentage can be important indicator of infarction myocardial developing into ventricular aneurysm.

Objective To explore the correlation between matrix metalloproteinase‐9(MMP‐9) and cardiac function ,aneu‐rysm volume in the process of left ventricular aneurysm (LVA) formation .Methods Rabbit models of LVA were established in 20 New Zealand rabbits by lighting left anterior descending artery and left circumflex artery .Two‐dimensional echocardiography were performed at preoperative and postoperative 1 d ,2 d ,3 d ,1 w ,2 w ,3 w ,4 w .The survived animals which had LVA formed were en‐rolled .Real time three‐dimensional echocardiography was performed to obtain left ventricular volume ,LVEF and LVA volume ,The MMP‐9 serum concentration was measured by ELISA .Results (1)There were a significant increase in the serum concentration of MMP‐9 from postoperative 1 d and arrived at the peak at postoperative 3 d ,there were higher than preoperative at postoperative 4 w (P<0 .05) .(2)Compared with preoperative ,the LVEDV ,LVESV and LVAV volume at postoperative showed an increase trend (P<0 .05) ,while there was a decreasing trend in LVEF(P<0 .05) .(3)The MMP‐9 had the better relationship with LVEF at post‐operative 1 d ,2 d ,3 d ,1 w ,2 w ,3 w ,4 w ,in which MMP‐9 had the tightest relationship with LVEF at postoperative 3 d (r=0 .731 , P<0 .05) .MMP‐9 had the better relationship with LVA volume at postoperative 2 d ,3 d ,1 w ,2 w ,3 w ,4 w ,in which MMP‐9 had the tightest relationship with LVA volume at postoperative 3 d (r=0 .636 ,P<0 .05) .Conclusion The MMP‐9 had an effect on cardiac function and LVA volume in the process of LVA formation .

Objective To study the change of thrombosis in rabbits arteries by electron microscope after thromb was lyses by urokinase targeted microbubbles.Methods A total of 24 rabbits with plateletrich thrombi in the femoral artery were randomized into 4 treatment groups (n = 6) :(1) ultrasound alone (US) ; (2) urokinase alone (UK); (3) ultrasound, non-targeted microbubble and urokinase (US + M + UK) ;(4) ultrasound, platelet-targeted microbubble and urokinase (US + R + UK).Urokinase targeted microbubbles were in conjunction with the surface of commercial microbubbles (SonoVue) by direct conjugation method.US was simultaneously applied transcutaneously over the thrombus up to 30 min.The thrombolytic effect was based on ultrasound, blood flow and histological observations at 120 min post treatment.Results US + R + UK group was completed recanalization (P ＜ 0.001).Scanning electron microscope examination showed thrombosis of the fiber network structure damage.Conclusions The main electron microscope change of RGDS urokinase targeted microbubbles dissolve thromb is thrombus fibrin network structure damage and fibrin dissolution.

Objective To evaluate the therapeutic effects of rAAV2-SERCA2a gene targeted to myocardium by the ultrasound mediated microbubbles in rats with myocardial infarction(MI) using speckle tracking echocardiography (STE). Methods Thirty-five male SD rats were divided into Sham group, MI group and gene therapy group. rAAV2-SERCA2a was attached to the surface of SonoVue, sulphur hexafluoride-filled microbubbles. Therapy group animals were infused with those mixed fluids through tail vein. The other two groups were infused with SonoVue microbubbles. These bubbles were infused with simultaneous echocardiography. Four weeks after ultrasound microbubbles destructed,Circumferential strain rate(SRcir), radial strain rate(SRrad) and left ventricular torsion (LVtor) of regional myocardium were measured in short-axis view using speckle tracking imaging software for each animal. Results Compared with the M1 group,there were significant increase in SRcir-S,SRcir-E, SRrad-S,SRrad-E and LVtor in rats of gene therapy group( P ＜0. 01 ). There was no significant difference between gene therapy group and sham group. Conclusions rAAV2-SERCA2a gene targeted to myocardium by the ultrasound mediated microbubbles could enhance cardiac function of rats with MI.

Objective To determine the effect of the combined use of urokinase and glycoprotein Ⅱb/Ⅲa-targeted microbubbles prepared by direct conjugation method to dissolve the thromb in vivo and analyse the velocity tracing change of blood flow and explore the possible mechanism. Methods A total of 42 rabbits with platelet-rich thrombi in the femoral artery were randomized into 7 treatment groups ( n = 6 in each group): 1) ultrasound alone (US); 2) ultrasound plus non-targeted microbubbles ( US + M); 3) urokinase alone (UK) ;4) ultrasound, non-targeted microbubble and urokinase (US + M + UK); 5) ultrasound plus platelet-targeted microbubble ( US + R); 6) platelet-targeted microbubble plus urokinase (R + UK); 7)ultrasound, platelet-targeted microbubble and urokinase (US + R + UK). A total of 6 ml of infusion liquor of Urokinase,RGDS and microbubbles (SonoVue) were mixed by 1 ∶ 1 ∶ 1 ratio by the direct conjugation method, infusion via vein within 20 min. Ultrasound was conducted to lyse the clot for 30 min. The recanalization and the velocity tracing change of blood flow in thrombolytic process were evaluated at 120 min post treatment. Results For US, UK, US + M, US + R and US + M + UK groups, recanalization was failed. The R + UK and US + R + UK was recanalizated ( P ＜0.001 ). The blood flow velocity tracing was small and low width in US,UK, US + M, US + R and US + M + UK groups. The wave was high width and disorderly under the thrombolysis therapy in the R + UK and US + R + UK. The thrombolytic effect was demonstrated by the high-width and disorderly resonance changes in the blood flow spectrum during the thrombolytic therapy of US + R + UK. Conclusions The blood flow spectrum of groups had different characteristics in vivo when thrombus was issolved,ultrasonic resonance might be the possible mechanism.

Objective To investigate the value of ultrasonography in evaluating the femoral artery thrombosis in rabbit. Methods Thrombosis was induced by external application with 10% ferric chloride and transient femoral artery-occlusion with bulldog clamp in twenty New-Zealand rabbits. The thrombosis was monitored by both Doppler flowmeter and ultrasonography. The histopathological result was used as the golden standard. The consistency of the above two results with the golden standard was analyzed. Results Thirty-two femoral arteries thrombosis were produced successfully. There was high consistency between the results of ultrasonic evaluation and histopathological examination (Kappa = 0. 720, P ＜ 0. 001 ), and moderate consistency between the results of Doppler flowmeter evaluation and histopathological examination (Kappa = 0. 546, P ＜0. 001 ). Within the thirty-two femoral arteries thrombosis, there were nineteen arteries with occlusive thrombus examined by histopathological means. Both the results of Doppler flowmeter and ultrasonography were highly consistent with the results of histopathological examination (Kappa = 0. 800 and 0.798 respectively, P ＜ 0. 001 ). Conclusions There is high consistency between the results of ultrasonic evaluation and histopathological examination for the common femoral artery thrombosis in rabbit.In the non-occlusive thrombus diagnosing,ultrasonography is better than Doppler flowmeter.

Objective To analyze the guidance demands of different levels of nursing students in initial stage of clinical practice,and implement student-development-centered and targeted teaching philosophy.Methods Scales and a home-made questionnaire were used to investigate 178 nursing students at different levels and the results underwent statistical analysis.Results In the early internships,guidance needs of psychology and basic knowledge were of consistency in undergraduate and college nursing students.There were some differences in guidance needs between secondary school students and undergraduate and college nursing students.The total average score of stress and all the subscale scores were at low and middle levels.The total average score of communication skills and all the subscale scores were above 2.5 points.The was statistically significant difference in joint participation dimension and verifying dimension.Conclusions Different levels of nursing students at the beginning of practice had different needs of guidance.Teachers should guide nursing students to face and deal with problems,relieve stress,improve communication skills,and handle interpersonal relationships well.Targeted guidance,management and meeting the specific needs of students can improve the effectiveness of teaching.

Objective To evaluate the value of peak time(PT) and corrected peak time(PTc) in the assessment of left ventricular long axis systolic function in patients with dilated cardiomyopathy(DCM).Methods Thirty-one DCM cases and thirty-six healthy cases were investigated using echocardiography.To obtain image of apical four-chamber view and apical two-chamber view, PT was measured by the technique of tissue motion annular displacement.The value of PTc was corrected by R-R interval.The critical value of PT and PTc was obtained by ROC curves.Results Compared with the PT of control group, the PT of DCM group at the site of septal and lateral were significantly increased ( P ＜0.05), but the PT at the site of anterior and inferior were no significantly increased ( P ＞0.05).The PTc at the four sites were significantly increased compared with control group ( P ＜0.05).The areas of under the ROC curve of PTc was 0.849 (95 % CI 0.699～0.929, P = 0.000), sensitivity and specificity of diagnosis cardiac dysfunction were 80.6 % and 66.7% respectively.Conclusions The PTc was significantly increased in patients with DCM.PTc was useful to evaluate left ventricular dysfunction in DCM patients.

ObjectiveTo evaluate the influence on left ventricular(LV) twist,and the relationship between LV twist and function in the rabbits with ventricular aneurysm formed after myocardial infarction by two-dimensional ultrasound speckle tracking imaging.MethodsTwenty-six healthy rabbits were divided into two groups,six as control group,twenty as experimental group.The model of myocardial infarction and ventricular aneurysm were established by ligaturing left anterior descending coronary artery and left circumflex artery.After four weeks,according to the pathological examination of whether ventricular aneurysm formed or not,the experimental group was divided into myocardial infarct group and ventricular aneurysm group.Echocardiography was performed to measure rotations (at the levels of mitral annulus and apex in LV short-axis view),LV twist,left ventricular cavity size and function.ResultsCompared with the myocardial infarct group,LV end-diastolic diameter(LVEDD) and LV end-diastolic volume(LVEDV) were larger in the ventricular aneurysm group,but LV ejection fraction (LVEF),LV fractional shortening (LVFS),apical rotation and LV twist were lower in the ventricular aneurysm group than the myocardial infarct group.Both apical rotation and LV twist had shown a great correlation with LVEF.The conclusion was also shown in the ROC curve that sensitivity and specificity of diagnosis cardiac dysfunction were 76.9％ and 80.0％ respectively when the apical rotation was 1.21°.Conclusions There was a closely relationship between the change of apical rotation and the LV systolic function.When the apical rotation dropped to 1.21°,an apparent decline of LV systolic function was implied.

BACKGROUND:Due to the different transplantation time after myocardial infarction, the homing ability of bone marrow mesenchymal stem cels to damaged tissues as wel as the repairing role wil be very different. OBJECTIVE:To explore the optimal window time for the homing of bone marrow mesenchymal stem cels to the myocardial tissue after myocardial infarction. METHODS: Eighteen Chinese miniature pigs were modeled by the ligation of left anterior descending coronary artery. BrdU-labeled bone marrow mesenchymal stem cels were injectedvia the coronary artery at 1 day, 3 days, 1 week, 2 weeks, 3 weeks, 4 weeks after modeling, respectively. Then, the animals were kiled at 3 days after cel transplantation to detect the home of bone marrow mesenchymal stem cels in the infarct zone. RESULTS AND CONCLUSION:BrdU-labeled positive cels with brown nuclei were visible at 1 day, 3 days, 1 week, 2 weeks, 3 weeks, and 4 weeks after myocardial infarction, especialy at 1 week after myocardial infarction (P < 0.05). It indicates that the best homing window for bone marrow mesenchymal stem cels was at week after myocardial infarction, when the stem cel transplantation is given to be able to promote myocardial repair.