极化心脏停搏液对离体大鼠心脏的保护作用

目的探讨Na+通道阻滞剂河豚毒素(tetraodontoxin,TTX)在极化状态下对离体大鼠心脏的保护作用. 方法将20只Wistar大鼠按体重均衡原则随机分成两组,每组10只.取出心脏建立Langendorff灌注模型和左心工作灌注模型,分别用去极化心脏停搏液(St.Thomas 2号液,STH-2组)和极化心脏停搏液(22 μmol/L TTX + K-H缓冲液,TTX组)停搏,低温保存5小时后再灌注心脏.观察两组心脏缺血前、后在心功能、心肌酶漏出量、三磷酸腺苷酶(ATPase)活性、再灌注后心肌胞浆游离Ca2+浓度和心肌超微结构等方面的改变. 结果恢复灌注后,TTX组心功能恢复明显优于STH-2组(P＜0.01),心肌酶漏出量较少(P＜0.05),各种ATPase维持较高的活性(P＜0.01),胞浆游离Ca2+浓度明显低于STH-2组(P＜0.01),心肌超微结构得到很好的保护. 结论以TTX阻断Na+通道为特点的极化心脏停搏液对大鼠心肌缺血-再灌注损伤的保护作用优于去极化心脏停搏液,有希望成为新型、有效的心脏停搏液和供者心脏保存液.     

老年糖尿病合并陈旧性心肌梗死患者新近发生冠状动脉事件的相关因素分析

目的 探讨老年糖尿病合并陈旧性心脲梗死(MI)患者新近发生冠状动脉事件的相关因素。方法 按照治疗方法，将346例老年糖尿病合并陈旧性心脲梗死患者分为磺脲类组，胰岛素组，二甲双胍类组，单纯饮食疗法组，分析各组治疗后新近冠状动脉事件的发生率及其影响因素。结果 新近冠状动脉事件的重要独立危险因素为：年龄(增加1岁危险率1．02)、吸烟(危险率1.36)、高血压病(危险率1．05)、LDL增高(危险率1.53)、HDL降低(危险率1.72)、使用磺脲类药物(危险率1．35)。结论 老年糖尿病合并陈旧性MI患者在饮食控制的基础上应选择胰岛素或二甲双胍类药物治疗，严格控制血压，积极降低LDL，提高HDL，避免单纯使用磺脲类药物。     

VEGF165cDNA治疗缺血心肌的实验研究

目的：观察VEGFl65cDNA治疗缺血心肌后心功能、血流动力学、心肌灌注和代谢的变化。方法：健康杂种犬36只，随机分为VEGFl65cDNA和空质粒(pcDNA3：1)组(n＝12)，心肌梗塞组为对照组。Amroid环致慢性心肌缺血模型。VEGFl65基因转染采用直接心肌注射法。结果：基因转染后4周、8周时VEGF165基因组LVEF和CO及前壁、前侧壁、前间壁心肌灌注量、代谢和FDG摄入量明显高于同期心肌梗塞组。结论：VEGFl65基因治疗后4周和8周时心功能显著改善；成活心肌的数量显著增加和/或称成活心肌功能显著恢复。     

介入法和无创法评价急性心肌梗死溶栓后心肌再灌注的一致性研究

目的 探讨急性心肌梗死（AMI）溶栓治疗后无创法评价心肌再灌注的可行性。方法选择AMI溶栓治疗后行冠状动脉造影的患者，溶栓后90min血浆肌红蛋白（Mb）浓度与溶栓前血浆Mb浓度比值≥2．4或心电图ST段回落≥50％定义为成功再灌注（阳性）。上述两项指标均阳性为完全再灌注，仅一项阳性为部分再灌注，两项均阴性为无再灌注。再根据冠状动脉造影结果将患者分为完全再灌注（TIMI3级）、部分再灌注（TIMI2级）、无再灌注（TIMI0～1级）。对无创法和介入法进行一致性检验。共入选45例患者。结果无创法和介入法评价心肌再灌注经一致性检验，符合率为84．4％，Kappa=0．75（P〈0．01）。结论．心电图ST段回落和血浆Mb浓度变化两项指标合用可提高评价心肌再灌注准确性，和介入法有很高的符合率，简便易行，且结果可靠。     

Left ventricle haemodynamics and vaso-active hormones during graded supine exercise in healthy male subjects

Left ventricle systolic and diastolic functional parameters were measured by gated equilibrium radionuclide cardiography in 12 healthy men (age 33–51 years) at rest and during graded supine exercise. The leftventricle end-diastolic volume showed an initial small (11%) increase during low submaximal exercise [from mean 163 (SD 40) at rest to mean 181 (SD 48) ml], while left ventricle end-systolic volume decreased successively [from mean 59 (SD 19) to mean 39 (SD 21) ml] with increasing exercise. Stroke volume was therefore elevated at all exercise levels compared with rest [mean 104 (SD 23) ml], and the peak value [mean 128 (SD 33) ml] was found at the lowest exercise level, contributing 40% to the initial increase in cardiac output. Cardiac output increased from mean 6.2 (SD 1.4) at rest to mean 20.2 (SD 5.0) 1 · min^–1 at maximum. Left ventricle peak ejection and peak filling rates increased from mean 449 (SD 89) and mean 442 (SD 85) ml · s^–1 at rest to mean 996 (SD 227) and mean 1255 (SD 333) ml · s^–1, respectively, at maximum. The myocardium oxygen consumption, assumed to be proportional to the sum of the stroke work and the potential energy, increased fourfold, but absolute values were twice as high as expected, indicating that extrapolation from data obtained in dog hearts (as we have done) cannot be directly applied to humans. Selected vaso-active hormones were measured at all exercise intensities. Noradrenaline (NA), adrenaline (A) and angiotensin II (AII) concentrations showed a very pronounced increase at maximal exercise compared with the preceding lower intensites, while atrial natriuretic factor (ANF) and cyclic guanosinemonophosphate (cGMP) concentrations showed a more continuous increase, and dopamine (DA) remained almost unchanged. This speaks in favour of a crucial role for NA, A and AII in preserving blood pressure at maximum exercise, while DA probably has no importance for the cardiovascular homeostasis during exercise. Increases in concentrations of ANF and cGMP were highly correlated (r = 0.86). Our data supported the opinion that there is a cardiac limitation to maximal performance connected to the cardiac pumping capacity.     

Short and long term effects of exercise training on the tonic autonomic modulation of heart rate variability after myocardial infarction

We studied the effects of cardiac rehabilitation on the sympathovagalcontrol of heart rate variability in 30 patients after a first,uncomplicated myocardial infarction. Twenty-two patients completed8 weeks of endurance training (trained), while eight decidednot to engage in the rehabilitation programme for logisticalreasons, and were taken as untrained controls. Age, site ofinfarction, ejection fraction, ventricular diameter and stresstest duration were similar in the two groups at baseline. Heartrate variability was evaluated 4 weeks after infarction beforestarting rehabilitation, and repeated 8 weeks and one year laterin both trained and untrained patients. Measures of heart ratevariability, obtained from both time- and frequency- domainanalysis of a 15 min ECG recording in resting conditions, wereas follows: mean RR interval and its standard deviation (RRSD),the mean square successive differences (MSSD), the percent ofRR intervals differing >50 ms from the preceding RR (pNTN50),the low and high frequency components of the autoregressivepower spectrum of the RR intervals and their ratio (LF/HF).At baseline, heart rate variability was similar in trained anduntrained patients. In the short term (8 weeks after infarction),training increased RRSD by 25% (P<0·01), MSSD by 69%(P<0·01), pNN50 by 120% (P<0·01), and reducedLF/HF ratio by 30% (P<0·01). The effects persistedafter one year in trained patients. In untrained patients, theautonomic control of heart rate variability did not change 8weeks after myocardial infarction and was only slightly modifiedby time. Thus, exercise training, performed for 8 weeks aftera myocardial infarction, modifies the sympathovagal controlof heart rate variability toward a persistent increase in parasympathetictone, known to be associated with a better prognosis. This maypartly account for the favourable outcome of patients who undergorehabilitation.     

Can marital selection explain the differences in health between married and divorced people? From a longitudinal study of a British birth cohort

In view of the rising divorce rates, the impact of divorce on health has an increasing importance in public health. The differentials in health between the married and the divorced may be explained by ‘marital selection’ and ‘marital protection’. Using longitudinal data from a study of the 1958 British birth cohort, factors that select people into divorce were identified from the areas of socio-economic status, health, and attractiveness, which included physical attractiveness, health-related behaviour and temperament. Evidence for both positive and adverse selection is found. The different sets of selection factors for females and males appear to be in line with gender role expectations. The health differentials between married and divorced men were weak and can be explained away by the selection factors. Having controlled for the selection effects, there were still significant associations between divorce and physical and psychological health in women. Though these unexplained differentials cannot be definitely interpreted as the consequences of marital dissolution, this interpretation remains plausible.     

Effects of calcium in continuous cardioplegia on myocardial protection

The effects of calcium (Ca) on a hyperkalemic cardioplegic solution for continuous cardioplegia were examined in an isolated perfused working rat heart model. The coronary arteries were perfused with a modified Krebs-Henseleit bicarbonate buffer (K-H) solution, containing various concentrations of Ca(0.1, 0.6, 1.2, and 2.5 mmol/l) and a high concentration of potassium (20 mmol/l), for 180 min, after which cardiac arrest was induced at 37°C for 180 min. Cardiac function and creatine kinase (CK) were measured. In the control group, K-H solution was infused in place of the cardioplegic solution, and cardiac arrest was not induced. No significant differences were observed between the groups infused with the K-H solution containing Ca concentrations of 0.6, 1.2, and 2.5 mmol/l in the percent recovery of aortic flow (82.1±2.9%, 80.6±2.0%, and 71.5±3.7% (mean±SEM) respectively) or in the recovery of other indices of cardiac function, or in CK leakage. There were also no significant differences in the recovery of cardiac function and CK leakage between these groups and the control group. In the Ca 0.1 mmol/l group, however, the characteristic Ca paradox was observed. These findings suggest that if the Ca concentration in a cardioplegic solution is higher than 0.6 mmol/l during continuous cardioplegia, excellent cardioprotective effects will be achieved.     

准分子激光心肌血管重建的实验研究

为研究心肌血管重建的机理,在15只鼠心、12只免心,用308nm的XeCl准分子激光在活体上照射左心室壁,形成边缘清楚而光滑的圆筒状心肌管道。在活体心室壁的激光管道周围,心肌细胞的损伤很轻微,无炭化焦痂层,未见碎片和凝固坏死层,只有薄层嗜伊红性变和肌浆凝聚两个断续的条形变化带。当心室壁由激光穿透时,血液从心腔进入激光管道,并与周围扩张的血管相通。实验结果提示,由于准分子激光不造成明显的热损伤,因而可能适合于心肌血管的重建。     

Myocardial scintigraphy — 25 years after start

The development of myocardial scintigraphy (MS) reflects the clinical success of a representative procedure in nuclear medicine. Radiopharmaceuticals for visualizing vital and damaged myocardium and techniques (planar-qualitative, planar-quantitative, SPECT-qualitative — quantitative with comparative sensitivities) are briefly reviewed with the main focus on their clinical application in coronary (CHD) and noncoronary heart disease, where recent literature from the United States and Europe is considered. The limited value of MS for screening of CHD is outlined and its present and future role in detecting asymptomatic (silent) ischemia/infarction and asymptomatic patients at professional risk is stressed. The present state of MS in coronary heart disease is discussed for single and multivessel disease, previous infarction, and risk stratification (myocardial washout, pulmonary uptake, ischemic dilation, absent heart sign), reflecting the importance of the procedure in exercise-induced ischemia as well as in ischemia at rest for prognostication of the natural and therapeutic course, i.e., therapy control (angioplasty, bypass, lysis, cardiac drugs). More marginal but upcoming clinical indications are mentioned, such as progressive systemic sclerosis, cardiac transplantation, pediatric cardiology, and problems of nephrology/urology. The normal values and the impact of digital radiology and of contrast cardiography are touched upon. Preliminary cases with ¹¹¹In-antimyosin and ^99mTc-Isonitriles are presented including correlative results between global ejection fraction determination according to gated ^99mTc-isonitrile and conventional ^99mTc-erythrocyte ventriculogram (r=0,75; n=10).Dedicated to Prof. Heinz Hundeshagen on the occasion of his 60th birthday