经静脉心肌声学造影剂的研制

目的 :制备可经静脉注射产生心肌对比增强效果的声学对比造影剂 ,观察其心肌显影效果。方法 :1按不同比例将 5 0 g· L- 1 葡萄糖或 9g· L- 1 Na Cl,C3 F8气体与人血白蛋白混合后进行超声振荡。 Coulter’ s计数器对造影剂进行质量分析。 2经犬股静脉注射自制对比造影剂 0 .2 ml,经胸壁扫查犬左室乳头肌水平短轴切面。结果 :1造影剂微泡液的相对浓度为 4 .2 3 9× 10 9/m l,微泡平均直径 3 .789μm,小于 9.89μm微泡占 99.5 %。 2经静脉注射后 ,均产生不同程度的心肌对比增强效果 ,心肌显影持续时间 1～ 3 min。注射前后犬血流动力学无显著性改变。结论 :自制经静脉注射对比造影剂符合心肌声学造影的要求 ;初步动物实验表明经静脉注射可产生肉眼可辨的心肌显影 ;反复注射无明显血流动力学改变     

经静脉途径注射自制声振白蛋白左心声学造影的实验研究

观察了经犬股静脉注入自制声振白蛋白左心显影效果．结果：本研究造影剂微泡直径４．２±２．４μｍ，浓度１６５±０６９×１０８／ｍｌ．经股静脉注射该造影剂共１０次，均见右室显影．５～８个心动周期后，左左室相继显影（显影率１００％）．持续约１１～３０个心动周期后左室造影作用消失．结论：声振５％人体白蛋白微泡直径小于红细胞，经犬股静脉注射后可实现满意的左室腔声学显影．如能应用到临床，将为超声心动图在冠心病室壁运动、心功能准确定量等方面提供帮助．     

经静脉心肌造影超声心动图的临床研究进展

近年来,超声造影剂的改进及显像技术的发展,使经静脉心肌造影超声心动图从基础研究逐步走向临床应用,在急性心肌梗塞的早期确诊、再灌注治疗措施的疗效评价、存活心肌的识别、冠心病的早期无创诊断及冠状动脉血流储备的评估等方面具有重要价值,且实时、简便、安全、无创。     

心肌对比超声心动图的临床应用

心肌对比超声心动图是心脏超声领域的新技术,可通过心肌灌注图像对冠状动脉微循环的完整性进行评价,因而常用于心肌缺血的诊断及缺血后心肌水平再灌注的疗效评价.     

经静脉左心室腔声学造影剂的研究——与Albunex对比分析

目的：用自制１％糖蛋白声学造影剂进行经静脉左心声学造影，观察左心室显影效果，并与国外同类造影剂Ａｌｂｕｎｅｘ对比分析。方法：对６０例经常规超声心动图检查无心内分流、瓣膜反流及明显狭窄的住院病人，从右上肢肘静脉以０．０８ｍｌ／ｋｇ浓度注入１％自制糖蛋白声学造影剂。如左心室显影效果在２＋以下，则于１５分钟后以０．２２ｍｌ／ｋｇ浓度重复造影１次。结果：自制造影剂的微泡浓度为（８．１±１．３）×１０８／ｍｌ，直径：３．８±１．４μｍ，９０％小于１０μｍ，稳定性在１０个月以上（２～８°Ｃ）。与Ａｌｂｕｎｅｘ各项指标相仿，但浓度较高。６０例左心室腔全部显影，成功率１００％，其中达２＋以上者５６例，占９３％；内膜边界增强者５７例，占９５％；心室壁运动可信性增强者５２例，占８７％，高于Ａｌｂｕｎｅｘ临床使用报告的相应结果。结论：用自制的声学造影剂经静脉注射取得良好的左心室显影效果，质量和性能与Ａｌｂｕｎｅｘ相仿，可在临床安全使用。     

心肌缺血再灌注前后心脏舒张功能的动态演变

为了评估心肌缺血再灌注前后的心脏功能转归，本文用脉冲式多普勒超声心动图，研究了３３例施行经皮穿刺窥状动脉或形术前后的左室舒张功能和收缩功能。分别测量了患者于ＰＴＶＡ术前和术后１，３，７，３０天的经二尖瓣血流频谱的舒张早期血流速度峰值和心房收缩期血流速度峰值，以及ＰＡ／ＰＥ值。     

超声心肌声学造影评价冠状动脉狭窄程度对心肌灌注的影响

目的经冠状动脉超声心肌声学造影(MCE)检测基础状态下不同狭窄程度冠状动脉所供应心肌组织灌注状况。方法30例患者行选择性冠状动脉造影,按有无冠状动脉病变及病变血管狭窄程度,将所涉及的共93个心肌节段分为对照组(18个)和病变组(75个),其中病变组又分为轻度狭窄组(12个)、中度狭窄组(28个)、重度狭窄组(35个);超声声学造影剂由冠状动脉直接注入,完成MCE。对心肌灌注进行定性分析,并由心肌灌注时间强度曲线进行定量分析。结果112个心肌节段中有93个(83.0%)获得较满意图像,经视觉判断,病变组共75个心肌节段中,正常灌注的为58个(77.3%),低灌注为17个(22.7%),其中,轻度狭窄组均为正常心肌灌注。定量分析显示,重度狭窄组反映心肌灌注的3个参数值与对照组均存在明显差异(P<0.05);而轻、中度狭窄组各参数值与对照组无明显差异。结论基础状态下,狭窄程度>90%的冠状动脉病变,其心肌组织灌注水平较正常偏低;而当血管狭窄程度≤90%时,心肌灌注水平与正常相似。     

静脉心肌声学造影在心肌梗死再灌注治疗及血管成形术中的应用

目的 :探讨静脉心肌声学造影 (MCE)评估急性心肌梗死再灌注治疗效果、冠状动脉介入治疗疗效以及预测存活心肌的价值。方法 :采用HP 5 5 0 0型超声心动仪 ,综合应用二次谐波、间歇成像和能量多普勒成像并采用高能量的超声波发射 ,对3 5例患者静脉注射利声显行MCE ,并行冠状动脉造影进行对比研究。结果 :3 5例患者完成MCE。 17例急性心肌梗死 (AMI)患者中 ,再灌注治疗患者MCE图象评分与保守治疗患者之间差异有显著性 (P <0 0 5 ) ;19例心肌梗死患者行介入治疗 ,共 63个血管重建术相关的心肌节段 ,在心肌梗死急性期 ,介入治疗前MCE显示心肌有灌注 ( 1分或 0 5分 )的心肌节段存活性及术后灌注改善的可能性显著高于MCE无灌注 ( 0分 )的心肌节段 (P <0 0 5 ) ,在心肌梗死陈旧期 ,介入治疗前MCE显示心肌灌注良好 ( 1分 )的心肌节段的存活性及术后灌注改善的可能性显著高于MCE灌注不佳 ( 0分或 0 5分 )的心肌节段 (P <0 0 5 )。结论 :结合多种成像技术 ,利声显可行静脉MCE。MCE可以评估AMI再灌注治疗的疗效 ,评估介入治疗的疗效并判断心肌存活性。     

GIK对缺血/再灌注犬心肌超微结构的影响

目的:观察葡萄糖-胰岛素-钾液（GIK）、葡萄糖-钾液（GK）对急性心肌缺血/再灌注（MI/R）犬心肌缺血区内心肌细胞改变的影响,分析GIK中的胰岛素对MI/R心肌细胞的保护作用。 方法: 将犬心肌定量缺血(左前降支血流量降低80%) 50 min,再灌注4 h,建立犬MI/R模型。24只杂种犬随机分为GIK组、GK组和盐水对照组(n=8),于再灌注前5 min,分别输注GIK、GK和生理盐水。再灌注4 h后,计算梗死区占缺血区重量的百分比,并制作电镜切片于透射电镜下观察。 结果: GIK可显著减少心肌梗死(MI)的范围［GIK组（5.2±0.8）% vs. 盐水对照组（9.4±0.8）%,P<0.05］;而GK组MI的范围（8.5±0.9）%则与盐水对照组无明显差异。与盐水对照组相比,GIK组对非缺血心肌的超微结构无影响,对缺血心肌有一定的保护作用。GK对缺血心肌无保护作用。结论: 再灌注时,静脉输注GIK可减轻心肌超微结构的损伤,其中的胰岛素是GIK上述作用的关键成分。     

银杏黄酮对急性心肌缺血/再灌注的药理作用

目的本研究通过观察银杏黄酮对家兔心肌缺血/再灌注的作用,为其临床应用寻找新的证据。方法家兔随机分为2组,对照组和银杏黄酮组,每组5只,口服给药,连续7d。以常规方法制备兔心肌缺血/再灌注模型。记录心率、血压、左心室内压、左心室内压微分变化。同时观察银杏黄酮对家兔急性心肌缺血/再灌注治疗后减轻心肌梗死的情况。结果心肌缺血及再灌注后心率、血压、左心室内压等在银杏黄酮治疗组与正常对照组无显著差异。左心室内压微分在心肌缺血和缺血/再灌注中,银杏黄酮组与对照组有显著差异（P<0.05）。银杏黄酮治疗后对家兔急性心肌缺血/再灌注可减轻心肌梗死,银杏黄酮组与对照组有显著差异（P<0.01）。结论银杏黄酮对急性心肌缺血/再灌注后心率、血压、心左室内压无明显影响,但却非常明显地减少由于缺血所造成的心肌组织的梗死面积。     

Digital radiofrequency echocardiography in the detection of myocardial contrast following intravenous administration of Albunex(R)

Conventional contrast echo techniques have proved inadequatefor the detection of myocardial perfusion using intravenouslyinjected echo contrast agents because of the limitations andrelative insensitivity of standard echocardiographic equipment.In order to avoid these problems, we have obtained pure digitalradiofrequency ultrasound data from the left ventricle and myocardiumduring i.v. contrast myocardial perfusion echo studies. In 30 patients, following coronary arteriography, i.v. injectionsof the echo contrast agent Albunex (sonicated human serum albumin)in two doses of 0.08 and 0.22ml . kg^–1 were administeredduring digital radiofrequency echocardiography sampling of datafrom the myocardium and left ventricular cavity. Analysis ofmean integrated backscatter (MIB, a measure of the total ultrasoundenergy) was performed before, during and after Albunex injection.The data were also analysed for a shift in frequency spectrumwhich could be caused by resonance of the Albunex contrast microspheresin the heart, a phenomenon which has been previously demonstratedin vitro. Digital radiofrequency ultrasound data were successfully obtainedand analysed in 23 patients. In 31 segments where reasonableresting perfusion was expected, there was a significant increasein MIB from 0.644 to 1.245, P<0.001 and time intensity curvescould be constructed showing wash-in and wash-out of contrastfrom the myocardium. In 10 segments supplied by significantlydiseased vessels, MIB intensity increased from 1.044 to 1.874,P=0.054. In myocardial segments supplied by non-diseased vessels,microsphere resonance also caused a drop in mean frequency of140 KHz, P<0.001 and permitted similar temporal analysisof myocardial perfusion. Frequency changes preceded intensitychanges in both the LV and myocardium by 2.3 beats and may representfaster pulmonary transmit of smaller contrast microspheres. In conclusion, digital radiofrequency ultrasound echocardiographicanalysis provides a method of detecting myocardial perfusionfollowing i.v. Albunex. It should provide the basis for futuremethods enabling study of organ tissue perfusion by ultrasoundfollowing i.v. injection of ultrasonic contrast agents.     

缺血期急性高血糖加重大鼠心肌缺血/再灌注损伤

目的探讨急性高血糖对大鼠心肌缺血/再灌注损伤（RMMI）缺血期和再灌注期的影响,并分析不同时期的高血糖与心肌损伤之间的关系。方法制备急性大鼠RMMI模型（缺血30 min,再灌注6 h）,静脉输注高浓度的葡萄糖液,造成急性高血糖动物模型。将SD大鼠随机分为4组:假手术组（SHAM）,生理盐水对照组（CON）,缺血期高糖组（HGI）和再灌注期高糖组（HGR）。术中监测血糖水平,再灌注结束后检测心肌酶谱（CK,LDH）水平和心肌梗死（MI）面积。结果静脉输注高糖后大鼠血糖水平迅速而显著升高,造成缺血期和再灌注期急性高血糖。与CON组相比较,HGI组心肌酶谱水平显著升高,MI面积显著扩大[（46±9）%vs（38±6）%,P<0.05];而HGR组的心肌酶谱水平和MI面积与CON组相比无显著差异[（39±6）%vs（38±6）%]。结论缺血期急性高血糖可加重大鼠RMMI。     

白细胞介素-17在心肌缺血再灌注损伤中的作用

目的:通过大鼠心肌缺血再灌注损伤(IRI)模型,分析白细胞介素-17(IL-17)在IRI中的作用。方法:用阻断大鼠冠状动脉左前降支的方法制作IRI模型。Realtime-PCR及Western blot方法动态观察IRI后不同时间点心肌组织IL-17的表达水平,流式细胞术进一步检测IL-17的来源。应用抗IL-17抗体体内干预,观察其对IRI的作用。结果:IRI后1h就有IL-17的表达,并且在24h的观察期内持续存在,未有峰值出现。流式细胞术检测结果显示心肌组织中IL-17的主要来源是CD4+T细胞。用抗IL-17的抗体体内干预后,血清肌钙蛋白T的水平降低,心肌梗死面积也明显减小。结论:IL-17参与大鼠IRI过程,中和IL-17能明显减轻心肌IRI。     

99mTc-NOET心肌灌注显像的初步临床应用

目的 :观察 99m Tc- NOET心肌灌注显像剂在心肌组织中的再分布特性及其对心脏缺血性疾病的诊断价值。方法 :对 5 2例冠心病心绞痛患者进行了运动负荷试验 ,静脉注射 99m Tc- NOET后 30 m in行心肌断层显像 ,3～ 4h行再分布显像。常规心肌断层显像采集和图像重建后观察放射性分布现象并评价其诊断价值。结果 :5 2例中 40例运动心肌灌注断层显像 1个以上节段出现放射性稀疏 -缺损区 ,38例出现明显放射性再分布。其中 5例同期做冠状动脉造影对照 ,4例与 99m Tc- NOET结论吻合。结论 :99m Tc- NOET是一种良好的新型心肌灌注显像示踪剂 ,它具有明显心肌再分布特性 ,对心肌缺血性病变的临床评价有价值     

Assessment of myocardial perfusion with intravenous contrast echocardiography: comparison with (99) Tc-tetrofosmin single photon emission computed tomography and dobutamine echocardiography

The aim of the study was to evaluate the accuracy of intermittent, harmonic power Doppler (HPD) during intravenous Levovist infusion in identifying myocardial perfusion abnormalities in patients with recent infarction. Fifty-five patients with first acute myocardial infarction, successfully treated by primary PTCA, were studied after 1 month by myocardial contrast echocardiography (MCE), 99mTc tetrofosmin single photon emission computed tomography (SPECT), and low dose dobutamine echocardiography (DE). Scoring myocardial perfusion as normal, moderately, or severely reduced; MCE and SPECT were in agreement in 71% of segments(k = 0.414). Discordance was mainly due to ventricular walls with normal enhancement by MCE and moderate perfusion abnormalities by SPECT. Scoring perfusion as present or absent, the agreement significantly improved up to 86% (k = 0.59). Sensitivity and specificity of HPD for identifying SPECT perfusion defects were 63% and 93%, respectively. The agreement between MCE and SPECT was higher(85%, k = 0.627)in patients with anterior infarction. An improvement in regional contractile function was noted after dobutamine in 79 dysfunctional segments. A normal perfusion or a moderate perfusion defect by MCE were detected in 71 of 79 of these segments, while a severe perfusion defect was observed in 59 of 85 ventricular segments without dobutamine-induced wall-motion improvement. Sensitivity and specificity by HPD in detecting segments with contractile reserve were 90% and 69%, respectively. Thus, intermittent HPD during Levovist infusion allows myocardial perfusion abnormalities to be detected in patients with recent infarction. This method has a limited sensitivity but a high specificity in detecting SPECT perfusion defects, and a good sensitivity but a limited specificity in detecting contractile reserve.     

微小RNA对缺血再灌注损伤心肌线粒体作用的研究进展

心肌缺血再灌注损伤是造成心肌结构损伤、功能障碍的一种病理生理过程,进一步发展会导致级联的多器官功能障碍。线粒体是一种结构功能复杂且对外界环境反应敏感的细胞器,其稳态的维持依赖于正常形态、功能及数量的相对稳定状态。线粒体质量与代谢异常和心血管疾病尤其是心肌缺血再灌注损伤的发生密切相关。微小RNA是近年来研究较多的在缺血再灌注损伤心肌线粒体保护中具有重要作用的调控因子。本文通过微小RNA对心肌缺血再灌注损伤时线粒体形态、功能、线粒体自噬和线粒体DNA几个方面的调控机制与相关前沿进展进行综述,为微小RNA参与缺血再灌注心肌线粒体损伤的后续研究提供一定的理论依据。     

Lymphatic diversion prevents myocardial edema following mesenteric ischemia/reperfusion

OBJECTIVE: Mesenteric ischemia/reperfusion (I/R) is associated with cardiac dysfunction. Mesenteric lymph primes polymorphonuclear leukocytes (PMNs) for increased superoxide release following I/R. We hypothesized that mesenteric I/R causes myocardial edema resulting in myocardial dysfunction, and that diverting mesenteric lymph would preserve myocardial function. METHODS: Two canine groups were studied: lymphatic diversion (LD) and no lymphatic diversion (No LD). Preload recruitable stroke work, +/-dp/dt(max), isovolumic relaxation (tau), cardiac output, and myocardial water content (MWC) were determined. I/R consisted of 60 min of ischemia followed by 180 min of reperfusion. Myocardial myeloperoxidase (MPO) was measured as an index of PMN leukosequestration. In addition, mesenteric lymph harvested after I/R was infused into normal canines and all variables measured. RESULTS: MWC increased from baseline in No LD. Tau and -dp/dt(max) were significantly affected in No LD, but not in LD. After mesenteric I/R, mesenteric lymph primed PMNs for increased superoxide production. Lymph diversion resulted in significantly lower myocardial MPO. With reinfusion of I/R lymph, MWC and tau increased. MPO was also increased post I/R mesenteric lymph reinfusion. CONCLUSIONS: Our data indicate that myocardial dysfunction after mesenteric I/R is due to lymph-induced, PMN-mediated microvascular alterations and myocardial edema.