Doppler tissue imaging of the heart in secondary amyloidosis

Secondary amyloidosis (SA) affects cardiac texture and function by interstitial fibrosis. Doppler tissue imaging (DTI) may quantify heart function through the assessment of myocardial velocities. Echocardiographic findings of early cardiac amyloidosis (CA) without heart failure (HF) caused by SA were determined both by standard methods and DTI. It was then determined whether DTI is superior to conventional echocardiography in documenting early CA due to SA. Twenty-five patients with SA who had CA without HF (group 1) were compared with 25 healthy control subjects (group 2). After standard echocardiography, systolic (s), early (e) and late diastolic (a) velocities of interventricular septum, anterolateral, and anterior and inferior walls were measured from mitral annulus by DTI. The averages were called (s_mean), (e_mean), and (a_mean), respectively. Fractional shortening (FS) and ejection fraction (EF) values of groups 1 and 2 were similar. Standard Doppler echocardiographic values were not typical for a specific diastolic abnormality. The (s_mean) and (e_mean) for group 1 were lower but (a_mean) was higher compared with group 2 (all P < .05). The group 1 (e_mean/a_mean) was lower (P < .0001) and (E/e_mean) was higher (P=.003) than in group 2 (both P < .05). (E/e_mean) and (E/e_{lateral wall}) ratios were positively correlated (r=0.74, P < .05). In patients with early CA due to SA without HF, by DTI, (s_mean) and (e_mean) velocities decrease and (a_mean) velocity increases. These may be markers of subclinical CA of SA when standard echocardiography is not informative. (E/e_mean) ratio may be an alternative index to (E/_{elateral wall}).     

肺缺血后适应对兔急性心肌缺血再灌注损伤的作用

目的通过在体兔心肌缺血再灌注模型，探讨肺缺血后适应是否具有减轻心肌缺血再灌注（I／R）损伤的作用及其可能的作用机制。方法将30只兔随机分成3组，每组10只。对照组：结扎冠状动脉左前降支（LAD）30min，再灌注3h。缺血后适应组：结扎LAD20min时阻断左肺动脉5min，然后松开5min，继而心肌再灌注至3h。药物＋缺血后适应组：于结扎LAD25min后经耳缘静脉注射一氧化氮合酶（eNOS）抑制剂L-NAME10mg／kg，余同缺血后适应组。分别于缺血前、再灌注开始前、再灌注3h末取兔血，测定各组血清肌酸激酶（CK）、丙二醛（MDA）、及超氧化物歧化酶（SOD）的水平。结果再灌注3h末，CK活性后适应组低于对照组和药物＋缺血后适应组，MDA活性后适应组低于对照组和药物＋后适应组，SOD活性后适应组高于对照组和药物＋后适应组。药物＋后适应组与对照组比较，CK活性、MDA活性和SOD活性均无统计学意义。结论肺缺血后适应对急性心肌缺血再灌注损伤具有保护作用；减少氧自由基的产生和释放NO是肺缺血后适应的作用机制。     

16例心肌致密化不全的临床特征

目的 分析16例心肌致密化不全(NVM)患者的临床特征和心脏彩超特点.方法 分析来自4个家系的9例NVM患者以及7例散发性NVM患者的临床表现、心电图、超声心动图等资料.结果 16例NVM患者,男12例,发病年龄17-74岁.7例患者有心悸症状;7例散发性NVM患者和2例家族性NVM患者有不同程度的心力衰竭;6例家族性NVM患者无明显症状.心电图异常者12例:室性期前收缩5例,非持续性室性心动过速3例,持续性房颤2例,阵发性房扑房颤1例,ST段压低伴T波改变9例.所有患者均通过心脏超声检查确诊,患者病变均局限于左心室;其中,累及心尖部14例,左心室扩大10例,左心室射血分数减低8例,左心室内见多发血栓1例.结论 NVM男性患者多见,有家族遗传倾向;其临床表现主要为心力衰竭、心律失常,超声心动图是确诊的主要方法.     

Optimal preservation of porcine cardiac tissue prior to diffusion tensor magnetic resonance imaging

The effects of ex vivo preservation techniques on the quality of diffusion tensor magnetic resonance imaging in hearts are poorly understood, and the optimal handling procedure prior to investigation remains to be determined. Therefore, 24 porcine hearts were examined in six groups treated with different preservation techniques, including chemical fixation and freezing. Diffusion properties of each heart were assessed with diffusion tensor imaging in terms of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (Da) and radial diffusivity (Dr). Tractography was performed to visualize the course of the cardiomyocytes, assuming greater diffusivity in the longitudinal than the transverse axis of individual cardiomyocytes. Significant differences in MD, Da and Dr were found, as well as in FA between groups (P < 0.001). Freezing of specimens resulted in the lowest mean FA of 0.21 (0.06) and highest Dr of 8.92 (1.5) mm² s⁻¹. The highest mean FA was found to be 0.43 (0.11) in hearts perfusion-fixed with formalin. Calculated tractographies were indistinguishable among groups except in frozen specimens, where no fibres could be tracked. Perfusion fixation with formalin provided the best tractography, but immersion fixation yielded diffusion data most similar to fresh hearts. These findings suggest that parameters derived from diffusion tensor imaging in ex vivo hearts are sensitive to fixation and storage methods. In particular, freezing of specimens should be avoided prior to diffusion tensor imaging investigation due to significant changes in diffusion parameters and subsequent image deteriorations.     

热预处理对超负荷训练大鼠心肌蛋白激酶C表达的影响

目的观察热预处理(HP)对超负荷训练大鼠心肌蛋白激酶C(PKC)δ、PKCε表达的影响。方法 3月龄雄性Sprague-Dawley大鼠25只分为对照组(n=5)、训练组(n=10)和HP组(n=10)。超负荷训练8周后应用免疫组化法、Real-time PCR和Western blotting检测心肌组织PKCδ、PKCε表达。结果三种检测方法均显示,训练组大鼠心肌PKCδ表达较对照组和HP组增高(P0.05)。Real-time PCR与免疫组化检测结果显示,训练组PKCε表达低于对照组和HP组(P0.05);Western blotting结果显示三组PKCε表达无显著性差异(P0.05)。结论在热预处理心肌保护效应中,PKC可能发挥了重要的作用。     

心脏端粒酶的研究概况

端粒长度、端粒酶活性在心血管疾病发生发展过程中的变化引起了心血管界的关注。现就端粒酶在正常心脏中的表达及活性的变化,端粒酶与心肌细胞损伤、冠状动脉粥样硬化、心力衰竭等心血管疾病之间的关系和检测心脏端粒长度和端粒酶活性的技术和方法作一综述。     

Nitric oxide: not just a negative inotrope

Nitric oxide (NO) appears to play a role in modulating cardiac function in both health and disease. Early studies in isolated rodent cardiac myocytes demonstrated a depressant effect of NO supplied by NO donors (exogenous) as well as NO generated within myocytes (endogenous). There is increasing evidence for a functional NO generating system within the human myocardium, which appears upregulated in certain disease states. Induction of the high output nitric oxide synthase isoform (iNOS) has been demonstrated in the failing myocardium, though its functional significance remains unproven. More recently published data have contradicted the notion that NO acts solely as a negative inotrope demonstrating positive inotropy in both isolated rodent and human ventricular myocytes in response to a range of NO donors. Different NO donors have different NO release kinetics and generate a range of NO species (NO., NO+ and NO-) which may interact at a number of subcellular targets. The observed response of any cardiac preparation to an NO donor represents the net effect of activation of different effector targets and may explain the contradictory reported effects of NO. To realise the therapeutic potential of NO will require specific targeting at a subcellular level.     

P-ERK、P-p38及iNOS、GLUT4在冠心病患者冬眠心肌中表达及意义

目的探讨冬眠心肌（HM）细胞内磷酸化ERK（P-ERK）、磷酸化p38（P-p38）、葡萄糖转运因子4（GLUT4）、诱导型一氧化氮合酶（iNOS）的变化和意义，探讨P-ERK、P-p38与GLUT4、iNOS的关系。方法选择行冠脉搭桥手术的冠心病患者10例，术前1周用多巴酚丁胺超声负荷试验结合多普勒组织成像确定HM及正常心肌（NM）的存在部位，术中根据检测结果取材，用免疫印迹法检测P-ERK、P-p38、iNOS、GLUT4的表达情况，分析HM与NM的P-ERK、P-p38、iNOS、GLUT4含量；分析四者之间的相关性。结果HM细胞内P-ERK、P-p38、GLUT4、iNOS水平较正常心肌高；P-ERK与GLUT4呈正相关（r=0.665，P〈0.05），P-p38与GLUT4、iNOS呈正相关（r=0.708、0.676，P〈0.05）。结论心肌缺血缺氧可触发ERK、p38活化，活化的ERK、p38促使心肌细胞增加GLUT4及iNOS表达，促进HM形成。     

不同类型干细胞在心肌组织工程中的应用及进展

慢性缺血性心脏病多由冠状动脉粥样硬化引起,目前治疗上较为棘手.近年来,心肌组织工程的发展为此疾病的治疗带来了曙光.心肌组织工程主要包括种子细胞的获取、支架材料的研制、以及心肌组织的构建三部分.种子细胞的来源和种类则是心肌组织工程中的关键环节.我们总结近年来干细胞研究的进展,对研究较多的几种干细胞在心肌组织工程中的应用作一综述,这些干细胞包括:心脏祖细胞,胚胎干细胞,间充质干细胞,诱导多能干细胞,以及用于构建心肌再生的内皮祖细胞等,并对未来干细胞的发展作一展望.