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Objective:To evaluate the effect of reactivated ultrasound contrast agent on prevention of ischemia-reperfusion (IR) injury in rat hindlimb ischemia model.Methods:Microbubbles were compressed into nanodroplets (NDs) and the particle size range was determined.In vitro experiments were carried out to observe the acoustic phase transition of nanodroplets in the ultrasound field and the change of dissolved oxygen (DO) concentration in the surrounding solution. Forty-one male Sprague Dawley rats were divided into 5 groups: acoustic nanodroplet vaporization treatment group (NDs+ US group, n=9), saline+ ultrasound treatment group (Saline+ US group, n=8), nanodroplet without ultrasound treatment group (NDs group, n=8), ischemia/reperfusion injury group (IRI group, n=8) and sham operation group (Sham group, n=8). Ultrasound imaging was performed before operation and 12 hours after reperfusion to evaluate the improvement of hemodynamics of criminal artery under different treatments. Tissue injury were evaluated by analyzing immunohistochemistry staining results. Results:The formed NDs ranged in size from approximately 68.0-295.4 nm and the highest concentration in the 100 nm range. In vitro studies, a decrease in DO was measured during the phase transition.In the animal experiment, after ischemia/reperfusion, NDs+ US, Saline+ US, NDs and IRI groups demonstrated a significantly higher resistance index (RI) and pualsatility index (PI) of the right common iliac artery compared with before operation (NDs+ US group: PI 1.79±0.17 vs 1.57±0.23, P=0.014; RI 0.80±0.02 vs 0.75±0.04, P=0.002. Saline+ US group: PI 2.29±0.16 vs 1.57±0.16, P<0.001; RI 0.90±0.06 vs 0.74±0.03, P<0.001. NDs group: PI 2.17±0.14 vs 1.53±0.15, P<0.001; RI 0.91±0.04 vs 0.75±0.04, P<0.001. IRI group: PI 2.12±0.22 vs 1.58±0.20, P<0.001; RI 0.88±0.04 vs 0.75±0.04, P<0.001). The increases of PI and RI (ΔPI, ΔRI) in NDs+ US group were higher than those in sham group (all P<0.05), but significantly lower than those in saline+ US group, NDS group and IRI group (all P<0.05). Immunohistochemical results indicated the percentages malondialdehyde (MDA) positive cells in Saline+ US, NDs and IRI groups were higher than those in NDs+ US and sham groups (all P<0.05). Conclusions:The acoustic phase transition of nanodroplets in the ultrasound field can reduce ischemia/reperfusion injury and improve hemodynamics abnormality after reperfusion.
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Objective: To test the feasibility of drag-reducing polymers (DRP) for improving coronary microcirculation in a canine model in order to provide the experimental basis for treating myocardial microcirculation dysfunction. Methods: A total of 8 dogs received open-chest surgery and they had intravenous injections, in turn, with adenosine (ADN), DRP 250 mg/L and DRP+ADN. The function y=A × (1-e-βt) was used to calculate the myocardium capillary volume (A value), capillary velocity (β value) and myocardial blood lfow (A ? β value) by myocardial contrast echocardiography. Results: With DRP infusion, the A value in experimental canine was similar to the baseline condition,P>0.05; while theβ value and A ? β value were signiifcantly increased as (0.57 ± 0.10) 1/s vs (0.23 ± 0.03) 1/s,P0.05. Conclusion: DRP improved coronary microcirculation primarily by modulating the β value in experimental canine model, and hopefully, this unique hemodynamics could provide a new approach for treating myocardial microcirculation dysfunction.
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Objective To evaluate the accuracy of the new and old electrocardiographic algorithms for differentiating the origins of outflow tract ventricular arrhythmias. Methods The clinical data of 202 patients treated between 2010 and 2013 were retrospectively reviewed for the investigations of the four algorithms including the transitional zone index, the V2 transition ratio, V2 R-wave duration and R/S-wave amplitude indices and the Sv2/Rv3 index. Results Regardless of rotation, the V2 transition ratio had the highest sensitivity (93.5%), while the Sv2/Rv3 index had the highest specificity (93.8). The maximal area under the ROC curve of four was more than 0.8, while the transitional zone index had the minimal area (0.804) with statistical significance (P 0.05). Conclusion Regardless of rotation, the Sv2/Rv3 index has the highest specificity and equal diagnostic value, with equal diagnostic value of the V2 transition ratio and V2 R-wave duration and R/S-wave amplitude indices. Compared with other algorithms, the Sv2/Rv3 index is simple and can be a complement as well for the direction of ablation therapy.
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Objective To evaluate left ventricular diastolic and systolic function of the dogs during different status of acute myocardial ischemia with velocity vector imaging (VVI). Methods Six healthy mongrel dogs were enrolled. Home-made artery constrictor was placed in the proximal coronary artery after opening the chest of dogs to produced different grades of coronary artery stenosis. Mean of peak diastolic velocity (Em), peak strain rate of diastole (Esr), mean of peak systolic velocity (Sm), peak strain rate of systole (Ssr), ejection fraction (EF) and left ventricular pressure were measured. Results There was good linear correlation between Em and Esr by VVI and left ventricular end diastolic pressure (LVEDP) (r=-0.834, P＜0.001 and r=-0.703, P＜0.001, respectively). Em and LVEDP had better correlation than that between Esr and LVEDP (P=0.032). Sm, Ssr or EF had significant correlation with +dp/dt_(max) (r=0.883, P＜0.001, r=0.772, P＜0.001 and r=0.647, P＜0.001, respectively). Significant difference was observed for correlation coefficient between Em and Esr and EF (P＜0.001). Conclusion Em and Sm are sensitive echocardiography indexes to evaluate left ventricular diastolic and systolic function, and are better than EF, Esr and Ssr.
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Objective To investigate whether non-critical coronary stenosis can be detected by coherent contrast imaging(CCI) at rest without stress.Methods Three degrees of stenosis were made in left anterior descending of 12 dogs.Myocardial contrast echocardiography(MCE) was performed with CCI and the correlation among the variables of MCE curve and the degrees of stenosis were analyzed by cubic regression.Results The time to peak was significantly prolonged with progressive coronary stenosis (P＜0.01) and related to the degree of stenosis (R~2=0.991,P＜0.001).Conclusions CCI could be used to detected non-critical coronary stenosis at rest without stress.
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BACKGROUND:By using ultrasound examination, renal function was conventionally assessed through measuring the blood flow parameters of large renal arteries in all levels and the rate of the color flow area in arter ies on the cross section of kidneys, in which method great errors have been induced.OBJECTIVE: This study was designed to assess the renal blood perfusion with use of the image analysis software package in the color Doppler system.DESIGN: It was an experimental study on animals.SETTING: This study was conducted in the Department of Functional Examination of Guangzhou First People' s Hospital.MATERIALS: The study had been accomplished at the Animal Laboratory of the General Hospital of Guangzhou Military Area Command of Chinese PLA from January 1999 to Aprial 2000. Eight healthy New Zealand rabbits were selected, 4 females and 4 males and weighing 2.5-3.5 kg.Sixteen kidneys of them were examined. A self-made contrast medium, with prevailing ingredient of albumin shelled and CsF8 gas-filled microbubbles,was used in this study.METHODS: After intravenous bolus injection of a fluorocarbon contrast medium, a color Doppler energy mapping, a color flow mapping and a power Doppler harmonic imaging of renal blood flow were collected successively and a time-density curve were created with system's standard software.MAIN OUTCOME MEASURES: The time-density curve of renal blood perfusion with contrast-enhanced color Doppler was a main outcome measurement in the study.RESULTS: All of the 8 rabbits entered the analysis procedure. The contrast-enhanced time-density curve of renal blood perfusion was singlepeaked, with a rapid incline and a subsequent slow decline. Quantitative analysis of interested sections could be performed by replaying the corresponding contrast-enhanced color Doppler images at a certain time after injection.CONCLUSION: The time-density curve of color flow mapping and color Doppler energy mapping is capable of reflecting the features of renal blood perfusion effectively. It can display not only the general renal perfusion but also the segmental regions with low perfusion, and thus to delineate the functional lesions in the kidneys.
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This paper introduces a programming cardiac trigger apparatus used for the study of quantitative measurement of myocardial blood flow with myocardial contrast echocardiography.The design of hardware circuit based on MCU and the scheme of software based on Keil C51 are mainly discussed.With stable and reliable working,this apparatus provides a kind of technical support for the study of quantitative measurement of myocardial blood flow with continuous intravenous injection of sonicated microbubbles.
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AIM:To explore the protective effect of ischemic preconditioning on myocardial capillary bed. METHODS: Anesthetized open-chest dogs in ischemic preconditioning (IP) group ( n =6) were subjected to 5 min ischemia and 5 min reperfusion for 4 times in left descending coronary artery (LDA) while the dogs in sham-operated (SO) group ( n =6) were observed for 40 min without any stimulating. Myocardial contrast echocardiography (MCE) was performed before the surgery, at the end of the first and the fourth ischemia and reperfusion period, respectively. Myocardial samples in ischemic area were obtained for capillaries ultrastructure examination and their quantitative analysis was conducted by corresponding imagine analyzing system, then compared within group and between control group. RESULTS: (1) Comparing fourth 5 min ischemia with first one, the percents of area defect in minimum (AD min%) by MCE decreased from 32.6%?5.7% to 21.8%?5.2%( P