左旋氨氯地平对急性心梗犬心肌细胞线粒体的影响

左旋氨氯地平是消旋体苯磺酸氨氯地平的左旋异构体,属于钙拮抗剂,具有用量小、血浆半衰期长、生物利用度高及药理作用广泛的特点。本实验观察了左旋氨氯地平对急性心肌梗死犬心肌细胞线粒体超微结构和形态计量学的影响,旨在探讨左旋氨氯地平是否存在对心肌细胞线粒体的保护作用。     

刺五加冻干粉针剂(ASHFI)对实验性心肌梗死犬心肌的影响

目的：观察刺五加冻千粉针剂(Acanthopanax senticosus harms freeze-dry injection ASHFI)对心肌三酶、心肌梗死面积、心肌细胞超微结构的影响。方法：采用麻醉开胸结扎犬的冠状动脉左前降支制备急性心肌梗死模型，取血测心肌三酶(AST、CPK、LDH)；组织学切片染色法和落点求积法测量心肌梗死区面积和非梗死区面积；采用透射电镜观察心肌细胞超微结构。结果：刺五加冻千粉针剂可以减少心肌三酶的释放，降低缺血造成的心肌细胞损伤，减少缺血心肌的梗死范围，对缺血心肌具有保护作用。     

心内膜心肌活检组织的超微结构研究—106例分析

近年,心内膜心肌活检技术在医学临床诊断上的应用日益广泛,为了探讨由不同病因引起的心肌超微结构形态变化,以及其对临床诊断的意义,我室从1986年开始累积了106例资料。透射电镜观察的结果表明:不同病因的心肌组织其超微结构病变部位主要在心肌细胞和心肌间质。一心肌细胞损伤根据损伤程度分为:(一)重度损伤;心肌细胞正常结构丧失,显示细胞坏死的特征。含此种变化的有15例。(二)轻度损伤:心肌细胞的结构存在,损害程度不一,主要改变有1.细胞器变性,其中较显著和普遍的是线粒体和内质网。2.局部肌原纤维、肌丝排列紊乱,灶性肌丝溶解。Z线形态和位置异常往往与肌丝紊     

米酵菌酸对小鼠肝和心肌细胞毒性作用的超微结构研究

目的：观察米酵菌酸对小鼠肝、心肌细胞毒性作用的超微结构改变，探讨米酵菌酸中毒的机理，方法：小鼠腹腔注射不同剂量的米酵菌酸，2h后取其肝和心肌组织，通过电镜观察其细胞超微结构的改变，结果：电镜下可见肝细胞和心肌细胞的线粒肿胀，内嵴断裂，模糊或消失，基质局部或全部空亮，呈囊泡样变，偶见其中含髓样小体，上述线粒体内嵴和膜结构的病变随米酵菌酸剂量的增加而加重，结论：米酵菌酸对小鼠肝、心肌细胞毒性作用以线粒体的损伤较为突出，因此我们认为，线粒体内膜的破坏造成线粒体的功能障碍，影响细胞呼吸，使细胞缺氧导致小鼠中毒死亡。     

酒精对心肌细胞超微结构及细胞色素C 氧化酶活性的影响

目的：通过给小鼠腹腔内注射不同浓度酒精,建立大量饮酒的动物模型,探讨酒精对心脏毒性作用的机理。方法：应用电镜技术观察心肌细胞的超微结构变化,以及酶细胞化学染色方法观察细胞色素C氧化酶(cytochrom C oxidase,Cox)活性的变化。结果：透射电镜下,实验各组心肌细胞肌原纤维排列紊乱,出现空泡,肌丝溶解,线粒体肿胀,嵴断裂甚至消失,细胞核形状不规则,部分染色质浓缩,边集于核膜下,呈斑块状;定位于线粒体内膜和嵴上的Cox活性减弱,电子密度降低。结论：酒精可以使心肌细胞超微结构发生异常改变,并且使线粒体上Cox活性减弱,从而导致心肌细胞结构和功能的改变。     

先天性胆道闭锁患儿心肌组织的电镜观察

利用透射电镜观察一例先天性胆道闭锁(biliary atresia,BA)患儿心肌组织的超微结构,发现心肌细胞内肌原纤维萎缩,排列紊乱,部位肌原纤维断裂.线粒体明显增生,空泡化现象或基质水肿并出现羊毛样致密物(wooly densities)常见.闰盘少又残缺.此结果说明,BA引起的高胆红素血症及高胆汁酸血症可严重损伤心肌细胞.     

大鼠心肌偶联的电镜及酶细胞化学研究

大鼠心肌偶联的电镜及酶细胞化学研究王仁鹏，吕银慧，陈希炜（第三军医大学中心实验室，重庆６３００３８）本文应用常规电镜和葡萄糖－６－磷酸酶（Ｇ６Ｐ酶）细胞化学技术对大鼠心房及心室心肌细胞的心肌偶联进行了超微结构观察，以期为心肌细胞的兴奋－收缩偶联功能提...     

人参皂苷Rg2对急性心源性休克犬心肌细胞线粒体的保护作用

研究表明人参皂苷能够增强心肌收缩力,增加心输出量,同时增强缺血心肌的血流量。本文通过对缺血心肌细胞线粒体超微结构的观察和形态计量分析,旨在探讨人参皂苷Rg2对缺血心肌细胞线粒体是否具有保护作用。     

透射电镜观察实验性心肌缺血再灌注时超微结构改变以及硝苯吡啶（心痛定）的保护作用

本文建立家兔心肌缺血再灌注模型，用透射电镜观察心肌细胞超微结构的变化以及应用硝苯吡啶（心痛定）的影响，结果对照组显示超微结构明显破坏，尤其是线粒体和细胞膜系统破坏严重。而用药组心肌细胞改变轻微，表明钙拮抗药能减轻心肌缺血再灌注时细胞超微结构的损伤。     

透射电镜观察实验性心肌缺血再灌注时超微结构改变以及硝苯吡…

本文建立家兔心肌缺血再灌注模型，用透射电镜观察心肌细胞超微结构的变化以及应用硝苯吡啶的影响，结果对照组显示超微结构明显破坏，尤其是线粒体和细胞膜系统破坏严重。而用药组心肌细胞改变轻微，表明钙拮抗药能减轻心肌缺血再灌注时细胞超微结构的损伤。     

KTP激光心肌血运重建术对急性心肌梗死犬心肌血运的影响

目的:观察:KTP激光心肌重建术(TMLR)对实验性心肌梗死中期血运动的影响。方法:家犬12只,结扎左前降支中段造成急性心肌梗死模型,随机分为TMLR组和对照组,TMLR激光在梗死区行TMLR,对照组则否。2一3月后,行~(99m)Tc一MIBI门挖断层心肌灌注显像,重建左室短轴、水平长轴、垂直长轴图象,将左室心肌分为20个心肌节段,按~(99m)Tc—MIBI摄取量分别为0—4分,比较其积分来评价两组动物心肌血运。结果:~(99m)Tc—MI-BI SPECT心肌灌注显象显示,实验组和对照组在左室水平长轴、垂直长轴和短轴上显示大部分左室前壁、部分间壁及心尖部~(99m)Tc—MIBI摄取明显减低或无摄取,与实验梗死部位相一致,两组心肌显像的总积分分别为20.0±8.9,23.6±4.7,两组之间比较无明显统计学差异(P>0.05)结论:KTP激光TMLR对急性心迹梗死犬2—3月后心肌运有改善的倾向,但效果不显著。     

A method for quantitative display of three-dimensional regional myocardial function

The DSR (dynamic spatial reconstructor), a multiple X-ray source scanner that generates stop action three-dimensional (3-D) images of a cylindrical volume, was used for quantitative imaging of left ventricular 3-D wall geometry and function in experimentally induced canine left ventricular myocardial infarction. Impaired regional myocardial function was induced by myocardial ischemia or infarction in four mongrel dogs by closed-chest occlusion of the proximal left anterior descending (LAD) coronary artery. At intervals of 6-14 weeks post occlusion, the dogs were scanned with the DSR during biatrial contrast injection. The 3-D shape, extent, and function of hypokinetic myocardium was measured from the DSR images utilizing measurement of the rate of local systolic wall thickening to detect regions of normal, ischemic, or scarred myocardium. The results were compared to scar size and anatomic distribution measured at postmortem examination. The anatomic extent and relationship of hypocontractile to normally contracting muscle was visualized by computer generated, pseudo 3-D shaded surface displays of the left ventricular chamber and by topographic projections of regional wall thickening rates onto a map of the left ventricular endocardial surface. The location of myocardial infarction and the surrounding zone of impaired function is clearly defined by this 3-D CT scanning procedure. The display method presented here provides both localization and quantification of the volume of ischemic and infarcted myocardium.     

Ho:YAG激光心肌血管重建术的实验研究

建立狗急性心肌梗塞实验模型,以SPECT观察钬激光心肌血管重建术后心肌缺血的改善情况及激光孔道的组织学变化,确定钬激光心肌血管重建术的有效性及适宜的激光参数,为钬激光心肌血管重建术的临床应用提供资料.     

Injection of ROS-Responsive Hydrogel Loaded with Basic Fibroblast Growth Factor into the Pericardial Cavity for Heart Repair

Myocardial infarction, among other ischemic heart diseases, is the major cause of mortality and morbidity for patients who have heart diseases. Timely reperfusion of the ischemic myocardium is the most effective way to treat myocardial infarction. However, blood reperfusion to the ischemic tissues leads to an overproduction of toxic reactive oxygen species (ROS), which can further exacerbate myocardial damage on top of ischemic injury. ROS has been used as a diagnostic marker and therapeutic target for ischemia-reperfusion (I/R) injury and as an environmental stimulus to trigger drug release. In this study, a ROS-sensitive cross-linked poly(vinyl alcohol) (PVA) hydrogel is synthesized to deliver basic fibroblast growth factor (bFGF) for myocardial repair. The therapeutic gel is injected into the pericardial cavity. Upon delivery, the hydrogel spread on the surface of the heart and form an epicardiac patch in situ. In a rat model of I/R injury, bFGF released from the gel could penetrate the myocardium. Such intervention protects cardiac function and reduces fibrosis in the post-I/R heart, with enhanced angiomyogenesis. Furthermore, the safety and feasibility of minimally invasive injection and access into the pericardial cavity in both pigs and human patients are demonstrated.     

An ultrasonic method for measuring tissue displacement: technicaldetails and validation for measuring myocardial thickening

We have developed a method for measuring myocardial thickening from a single ultrasonic transducer attached to the epicardium. Displacement of the underlying myocardial tissue is measured by following the phase of the echoes within a sample volume range-gated across the myocardium. The output is in the form of an analog signal. To verify the accuracy, resolution, and limitations of the system, we derived the equations relating the position of a reflector to the phase of its echo and compared the system output in vitro to a known input using a single moving target and a random distribution of scatterers, and in vivo to that of an ultrasonic transit-time dimension gauge. The results demonstrate that the 10 MHz system can accurately follow the motion of single or multiple targets with a resolution of 0.02 mm. In 25 dogs myocardial thickening measured with the displacement system compared favorably in both waveform and magnitude with thickening measured by the two-crystal transit-time method. Applications for the displacement method include: quantification of regional ventricular function in animal models of cardiovascular diseases, measurement of endocardial to epicardial differences in the deformation of regional myocardium during the cardiac cycle, and evaluation of regional cardiac function in patients during and after corrective cardiac surgery.     

Classification of Heart Tissue from Bipolar and Unipolar Intramural Potentials

The purpose of this study is to evaluate how well bipolar and intramural potentials are able to classify the state of the myocardium (normal or infarcted) proximal to the electrode recording sites. Nine mongrel dogs with anterior myocardial infarcts were used to generate a database for the study. Classification of the myocardium as normal or infarcted was attempted from potentials recorded in and around the infarcted region using electrodes within plunge needles. In addition to the potentials, the database contains the locations of the plunge needles, the grossly visible borders of the infarcts, and the epicardium and endocardium of both ventricles.     

Mussel‐Inspired Conductive Cryogel as Cardiac Tissue Patch to Repair Myocardial Infarction by Migration of Conductive Nanoparticles

The engineered cardiac patch (ECP) is a promising strategy to repair infarct myocardium and restore the cardiac function. An ideal ECP should be able to mimic the primary attributes of native myocardium, which includes a high resilience, good cardiomyocyte adhesion, and synchronous contraction. Here, a mussel‐inspired dopamine crosslinker is used to integrate polypyrrole (Ppy) nanoparticles, gelatin‐methyacrylate, and poly(ethylene glycol) diacrylate into a cryogel form. The dopamine crosslinker and Ppy nanoparticles are coordinated to obtain optimal mechanical and superelastic properties for the ECP. The dopamine facilitates the uniform distribution of the Ppy nanoparticles, which migrate and fuse from the scaffold to the surface of the cardiomyocytes, revealing a potential mechanism for restoring infarct myocardium. The incorporated Ppy nanoparticles thus significantly enhance the functionalization of the cardiomyocytes, resulting in excellent synchronous contraction by increasing the expression of α‐actinin and CX‐43. Cardiomyocytes‐loaded ECP can improve the cardiac function in myocardial‐infarction (MI) affected rat models. The results show that the fractional shortening and ejection fraction are elevated by about 50% and that the infarct size is reduced by 42.6%. Collectively, this study highlights an effective cardiac patch based on mussel‐inspired conductive particle adhesion and a superelastic cryogel promising for the restoration of infarcted myocardium.     

Estimation of Regional Myocardial Blood Flow Using Computed Tomography: A Stochastic Formulation

Previously, we have presented a deterministic formulation for estimation of regional myocardial blood flow (RMBF) using X-ray computed tomography (CT) [1]. Quantitation of RMBF with the deterministic theory requires computing the zeroth and first moments of extrapolated myocardial contrast enhancement (CT numbers versus time) curves. This extrapolation is a potential source of error in the presence of recirculation, especially in myocardial regions with reduced flows. In the present paper, a stochastic approach for parameter estimation is undertaken, which renders an optimal RMBF estimate based upon the least squares error criteria. Random measurement errors are minimized, curve extrapolation is avoided, and the accuracy of RMBF estimates is predicted. The advantages of the stochastic versus the deterministic approach are demonstrated in the results obtained from the in vivo estimation of RMBF in normal and acutely ischemic myocardium of dogs.