犬心肌缺血后脂质过氧化损伤及绞股蓝总皂甙的干预效应

目的 观察绞股蓝总皂甙对犬冠脉结扎急性心肌缺血后脂质过氧化和超微结构的影响.方法 采用麻醉开胸犬结扎左冠状动脉前降支(LAD)制备急性心肌缺血模型,观察绞股蓝总皂甙对磷酸肌酸激酶(CK)、乳酸脱氢酶(LDH)、游离脂肪酸(FFA)、过氧化脂质(LPO)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物(GSH-Px)的影响.用JEM-1200EX型透射电子显微镜观察心肌细胞超微结构的变化.结果 绞股蓝总皂甙降低血清CK、LDH的活性,降低血清FFA、LPO含量,提高SOD、GSH-Px活性.改善缺血心肌电镜下的细胞损伤.结论 绞股蓝总皂甙对实验性心肌缺血犬脂质过氧化损伤具有保护作用.     

巴戟天醇提物对实验性心肌缺血及缺氧再给氧损伤的影响

目的 研究巴戟天醇提物对实验性心肌缺血及缺氧再给氧损伤的影响.方法 取杂种犬30只,随机分为模型组、阳性药对照组(刺五加注射液,10.0 mg/kg)、巴戟天醇提物(2.5、5.0、10.0 mg/kg)组每组6只.结扎犬左冠状动脉前降支,制备急性心肌梗死模型,观察巴戟天醇提物对磷酸肌酸激酶(CK)、乳酸脱氢酶(LDH)、天门冬氨酸氨基转移酶(AST)、游离脂肪酸(FFA)、过氧化脂质(LPO)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物(GSH-Px)的影响.新生大鼠随机分为正常组,损伤组,阳性药对照组(刺五加注射液),巴戟天醇提物1000、500、250 μg/ml组,每组8只.观察巴戟天醇提物对缺氧缺糖新生大鼠心肌细胞LDH的影响.结果 巴戟天醇提物降低血清中CK、LDH、AST的活性,降低血清中FFA、LPO含量,提高SOD、GSH-Px活性,减少新生大鼠心肌细胞LDH的释放.结论 巴戟天醇提物对实验性心肌缺血引起的脂质过氧化损伤具有保护作用.     

熊果酸对急性心肌梗死小鼠氧化应激和脂质代谢的影响

目的观察熊果酸对急性心肌梗死小鼠心肌的保护作用机制。方法 30只C57小鼠随机均分为假手术组、急性心肌梗死模型组和熊果酸组。熊果酸组和急性心肌梗死模型组结扎冠状动脉左前降支6 h,收集各组小鼠心脏和血清。硝基四氮唑(NBT)染色检测心肌梗死面积,HE染色检测心肌病理形态,全自动生化分析仪检测血清乳酸脱氢酶(LDH)、磷酸肌酸激酶(CPK)、心肌肌钙蛋白I(cTnⅠ)、甘油三酯(TG)、总胆固醇(TC)、低密度脂蛋白胆固醇(LDLC)、高密度脂蛋白胆固醇(HDLC)水平,硫代巴比妥酸(TBA)法检测心肌丙二醛(MDA)、脂质过氧化物(LPO)和游离脂肪酸(FFA)含量,黄嘌呤氧化酶法检测心肌过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GPx)和超氧化物歧化酶(SOD)活性,放射免疫法检测血浆6-酮-前列腺素F1α(6-Keto-PGF1α)及血栓素A2(TXA2)含量。结果与假手术组相比,急性心肌梗死模型组心肌梗死面积、血清LDH、cTnⅠ、CPK、TC、TG及LDLC水平、心肌LPO和MDA含量、血浆TXA2、心肌梗死区和非梗死区FFA含量以及心肌病理形态改变均明显增加,但血清CAT、GPx和SOD活性以及HDLC和6-Keto-PGF1α含量均明显减少。与急性心肌梗死模型组相比,熊果酸组心肌梗死面积、血清LDH、cTnⅠ、CPK、TC、TG和LDLC水平、心肌LPO和MDA含量、血浆中TXA2、心肌梗死区和非梗死区FFA含量以及心肌病理形态改变均明显减少,而血清CAT、GPx和SOD活性以及HDLC和6-Keto-PGF1α含量均明显增加。结论熊果酸对急性心肌梗死有明显的保护作用,其作用机制与抑制氧化应激损伤和改善脂质代谢紊乱相关。     

雷米普利对实验性心衰大鼠的抗氧化作用

目的 研究雷米普利通过抗氧化作用改善大鼠心衰的作用机制.方法 结扎大鼠左冠状动脉前降支造模成功并饲养6 w的16只存活大鼠随机分为模型组及雷米普利组,每组8只,另随机选9只作为假手术组(麻醉开胸后只穿刺不结扎,1只死于麻醉意外),连续灌胃给药4 w后测定全血黏度,检测血清超氧化物歧化酶(SOD)活性,血清丙二醛(MDA)、脂质过氧化物(LPO)、游离脂肪酸(FFA)含量,并通过HE染色观察梗死区心肌组织形态学变化.结果 雷米普利可明显降低MDA、LPO及FFA含量,提高SOD活性,并能减轻梗死区心肌细胞肥大及间质纤维化.结论 雷米普利改善左室重构的作用机制可能与其增强抗氧化酶活性,减少自由基对心肌的氧化损伤有关.     

龙芽葱木皂苷对犬急性心肌缺血的保护作用

目的观察龙芽葱木皂苷(AS)对犬急性心肌缺血的保护作用。方法取杂种犬24只,随机分为4组(每组6只),分别为空白对照组、阳性对照药物(地奥心血康胶囊)组,AS30.0和60.0 mg.kg-1剂量组;采用结扎麻醉开胸犬左冠状动脉前降支(LAD)产生急性心肌缺血模型,观察AS对心肌梗死面积(M IS)、血清中磷酸肌酸激酶(CPK)、乳酸脱氢酶(LDH)、超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)活性及血清中游离脂肪酸(FFA)和过氧化脂质(LPO)含量和无机元素含量的影响。结果AS各剂量组与空白对照组比较,显著缩小心肌M IS(P<0.05,P<0.01),降低血清中CPK和LDH的活性(P<0.05,P<0.01),提高SOD和GSH-Px活性(P<0.05,P<0.01)。降低血清中FFA和LPO含量(P<0.05,P<0.01),无机元素铜(Cu)含量显著减少(P<0.05,P<0.01)、锌(Zn)和钙(Ca)含量显著增加(P<0.05,P<0.01)。结论AS对犬急性心肌缺血具有一定的保护作用。     

黄杨宁缓释片对犬急性心肌缺血的保护作用

目的比较黄杨宁缓释片和黄杨宁片对犬急性心肌缺血的保护作用。方法采用结扎麻醉开胸犬左冠状动脉前降支(LAD)产生急性心肌缺血模型,观察黄杨宁缓释片对心外膜电图(EECG)、心肌梗死面积(MIS)和血清心肌酶的影响。结果黄杨宁缓释片和黄杨宁片均可减少缺血程度(∑-ST),降低缺血范围(NST),缩小缺血心肌的MIS,降低血清中磷酸肌酸激酶(CPK)、乳酸脱氢酶(LDH)、谷草转氨酶(AST)的活性,降低血清中游离脂肪酸(FFA)、过氧化脂质(LPO)含量,提高超氧化物歧化酶(SOD)、谷胱甘肽过氧化物(GSH-Px)活性。结论黄杨宁缓释片和黄杨宁片均能够减轻心肌缺血性损伤;黄杨宁缓释片具有作用时间长的特点,可以取代黄杨宁片。     

龙眼参黄酮对急性心肌梗死犬心肌超微结构的影响

目的 观察龙眼参黄酮对急性心肌梗死犬心肌超微结构的影响.方法 取杂种犬24只,随机分为4组(每组6只),分别为模型组、阳性药(地奥心血康胶囊)组,龙眼参黄酮30.0 mg/kg和60.0 mg/kg剂量组;结扎麻醉开胸犬左冠状动脉前降支建立急性心肌缺血模型,采用JEM-1200EX型透射电子显微镜观察龙眼参黄酮对心肌细胞超微结构的影响.HE染色,OLYMPUS BX50显微镜观察龙眼参黄酮对心肌纤维结构的影响.结果 与模型组比较,龙眼参黄酮能够明显改善急性心肌缺血所致的心肌光镜及电镜下细胞结构的损伤程度.结论 龙眼参黄酮对犬急性心肌缺血损伤时的心肌细胞具有明显的保护作用.     

急性心肌缺血犬心肌超微结构的变化及龙牙葱木皂苷的保护作用

目的 观察犬急性心肌缺血时心肌超微结构的变化及龙牙葱木皂苷的保护作用.方法 取杂种犬24只,随机分为模型组、阳性药(地奥心血康胶囊)组,龙牙葱木皂苷30.0和60.0 mg/kg剂量组;结扎麻醉开胸犬左冠状动脉前降支(LAD)建立急性心肌缺血模型,观察龙牙葱木皂苷对心肌细胞结构的影响.结果 与模型组比较,龙牙葱木皂苷能够明显改善急性心肌缺血所致的心肌光镜及电镜下细胞结构的损伤程度.结论 龙牙葱木皂苷对犬急性心肌缺血损伤时的心肌细胞具有明显的保护作用.     

丙酮酸对顿抑心肌功能及能量代谢的作用

目的　了解丙酮酸对顿抑心肌功能及能量代谢的影响 ,并分析其可能机制。方法　结扎家兔左冠状动脉前降支 2 0min后 ,再灌注 6h造成短暂缺血 再灌注心肌顿抑模型 ,观察血流动力学、抗氧化酶、脂质过氧化物、血清游离脂肪酸 (FFA)、乳酸 (LD)以及心肌组织的ATP含量和超微结构变化。结果　与顿抑组比较 ,丙酮酸可明显缓解缺血及再灌后心肌功能的损害 ,抑制血清FFA、LD水平的升高 ,降低MDA含量 ,提高SOD活性 ,抑制心肌组织ATP含量降低 ;电镜所见心肌损伤明显比顿抑组轻。丙酮酸组与对照组比较 ,各指标均为显著性差异。结论　丙酮酸可以减少心肌细胞能量消耗 ,保护线粒体的结构和功能 ,对顿抑心肌具有一定保护作用     

西洋参茎叶总皂苷对心室重构大鼠的保护作用

目的 研究西洋参茎叶总皂苷(PQS)对急性心梗后心室重构大鼠的保护作用.方法 结扎大鼠左冠状动脉前降支制备心室重构模型,将Wistar大鼠随机分为假手术组、模型组及PQS小剂量组(75 mg/kg)、大剂量组(150 mg/kg),连续灌胃给药6 w后测量心肌形态学,测定血清MDA、NO含量及SOD活性,放射免疫分析法测定血浆ET水平.结果 西洋参茎叶总皂苷组连续给药6 w后能明显降低脏器指数、血清MDA含量及血浆ET水平,升高血清SOD活性及NO的含量.结论 PQS可能通过对抗自由基的氧化损伤,改善心肌代谢对心室重构的大鼠发挥保护作用.     

Assessment of myocardial viability using myocardial contrast echocardiography

Myocardial contrast echocardiography (MCE) is a technique that uses microbubbles as a tracer during simultaneous ultrasound of the heart. The microbubbles can be used to provide quantitative information regarding the adequacy of myocardial blood flow (MBF), as well as the spatial extent of microvascular integrity. In acute myocardial infarction, MCE can identify the presence of collateral flow within the risk area, and can therefore predict preservation of myocardial viability and ultimate infarct size even prior to reperfusion. After reperfusion, the extent of microvascular no-reflow can be determined, and has significant implications for recovery of left ventricular function. In chronic ischemic heart disease, MCE has also been shown to successfully differentiate viable from necrotic myocardium. This technique can accurately predict recovery of function after revascularization. More importantly, MCE can be used to identify viable segments that may help to prevent infarct expansion and remodeling, and thus improve patient outcomes.     

Assessment of myocardial viability with myocardial contrast echocardiography

The application of noninvasive imaging techniques to assess myocardial viability has become an important part of routine management of patients with acute myocardial infarction and chronic coronary artery disease. Information regarding the presence and extent of viability may help identify patients likely to benefit from revascularization or therapy directed at attenuating left ventricular remodeling. Myocardial contrast echocardiography (MCE) is capable of defining the presence and extent of viability by providing an accurate assessment of microvascular integrity needed to maintain myocellular viability. It is especially suited for the spatial assessment of perfusion, even when myocardial blood flow is reduced substantially in the presence of severe epicardial stenoses or in a bed dependent on collateral perfusion. The routine use of MCE to evaluate viability in patients with acute and chronic coronary artery disease is now feasible with the advent of new imaging technologies and microbubble agents capable of myocardial opacification from venous injections. The utility of this technique for determining treatment strategies has not been established but is forthcoming.     

Anaerobic myocardial abscess following myocardial infarction

An anaerobic myocardial abscess due to Bacteroides fragilis developed in a 60-year-old man when he had an acute myocardial infarction while recuperating from surgery for a paracolonic abscess. Anaerobic bacteremia is a common event and may lead to infection in areas of low oxygen tension far removed from the original portal of entry.     

经静脉心肌声学造影评价心肌梗死后存活心肌的价值

目的　探讨经静脉心肌声学造影 (MCE)对心肌梗死后存活心肌的诊断价值。方法　 2 4例心肌梗死患者用二维超声评价室壁运动情况 ,同时经静脉进行MCE ,以 3个月后静态超声心动图左室心肌节段性运动改善为依据评价MCE对心肌梗死后存活心肌的诊断价值。结果　在 2 4例病人的 384个心肌节段中 ,运动异常节段 184个。在运动异常的 184个节段中 ,MCE1分 39段 ,0 5分 5 0段 ,0分 95段。 3个月复查 79个节段有运动改善 ,其中 39段来自MCE1分的心肌 ,4 0段来自MCE0 5分的心肌。MCE对预测心肌梗死后室壁运动改善的敏感性、特异性、阳性预测值、阴性预测值及准确率分别为 :10 0 %、89 7%、84 8%、10 0 %和 94 6 %。结论　MCE能比较准确地预测心肌梗死后心肌的存活性     

Differentiation of aborted myocardial infarction from masquerading myocardial infarction

We read with great interest the article by Verheugt et al.¹dealing with aborted myocardial infarction (MI) as a new targetfor reperfusion     

Assessment of fetal myocardial performance using myocardial deformation analysis

Conventional techniques for the assessment of cardiac function on the basis of M-mode or 2-dimensional modalities are technically difficult, load dependent, and provide information on global ventricular function only. Newer techniques, which analyze myocardial performance, such as tissue velocity, strain, and especially the less load dependent strain rate, may provide more appropriate information. Myocardial systolic and diastolic motion and performance were calculated using tissue velocity, strain, and strain rate imaging on a large cohort of normal fetuses. The assessment of myocardial performance was feasible in all 98 normal fetuses. Normal systolic and diastolic values for tissue velocity, strain, and strain rate were established. All data were highly reproducible. Tissue velocity was age dependent, whereas strain and strain rate were stable throughout gestation. All parameters were heart rate independent. In conclusion, fetal myocardial velocity, strain, and strain rate measurements are easy to obtain and reproducible, and therefore, may serve as reference data. Increases in tissue velocity throughout gestation probably reflect the growth of the fetal heart, whereas intrinsic myocardial properties as measured by strain rate do not change. In comparison with recently published myocardial performance values in children, these strain rate data suggest that fetal myocontractile properties that are already established during the second half of pregnancy remain constant throughout gestation and after birth.     

Effects of myocardial hypoxia and ischemia on myocardial scintigraphy

The effect of regional myocardial ischemia and hypoxia on myocardial scintigraphy was studied in patients and dogs after intravenous administration of cesium-129. Seven men with angiographically proved ischemic heart disease underwent exercise testing and ¹²⁹Cs was given immediately when ischemia was manifested in the electrocardiogram. Defects were not evident in the scintigrams of any patient. Failure to visualize a defect might be related to delayed uptake of ¹²⁹Cs by the myocardium (maximal uptake in 45 minutes). The ischemic state was dissipated before the disparity in uptake between normal and ischemic myocardium could be visualized. Cesium-129 is useful for identifying acute myocardial infarcts but should not be used to visualize transient exercise-induced regional ischemia.Six dogs were given ¹²⁹Cs after induction of regional myocardial hypoxia by perfusion of the anterior descending coronary artery with venous blood. In each, scintigraphy revealed a defect that resolved after reperfusion with arterial blood. Two other dogs were given ¹²⁹Cs before perfusion with hypoxemic blood; neither dog manifested a defect. Since perfusion was maintained by a pump these results suggest that the major cause of the scintigraphically observed defect was inadequate cellular uptake of ¹²⁹Cs rather than excessive cellular loss. Since regional myocardial hypoxia produced a reversible defect, scintigraphic studies might overestimate the size of an acute myocardial infarct in man by including the ischemic zone surrounding the infarct.     

心肌缺血预适应对急性心肌梗死影响的观察

目的:探讨心肌缺血预适应对急性心肌梗死(AMI)临床表现及其预后的影响。方法:根据AMI前有无心绞痛发作分为预缺血组和无预缺血组,分组观察AMI患者血清肌酸磷酸激酶(CPK)峰值,住院期间并发症(心衰、心源性休克、严重心律失常),以及住院期间心性病死率。结果:预缺血组血清CPK峰值明显低于无预缺血组(P<0.05),住院期间心源性休克及严重心律失常发生率明显低于无预缺血组(P<0.05)。结论:心肌缺血预适应可减轻心肌坏死程度,缩小梗死面积,并减少AMI并发症的产生。