栝蒌对家兔急性心肌缺血再灌的保护作用

以脂质过氧化物含量(MAD),超氧物歧化酶(SOD)活性及心肌出血为指标观察栝萎对家兔心肌缺血再灌注损伤的保护作用。结果表明枯萎能减轻缺血再灌注区心肌 MAD 的升高反应,提高 SOD 活性,降低再灌后缺血心肌的出血率。     

实验性雷公藤中毒的超微病理学研究

本文对实验性急性雷公藤中毒进行了电子显微镜观察,发现明显的心肌病变,其主要特征为多发性微小肌溶灶的形成;肾脏主要病变为肾小管细胞的变性及坏死;脾脏的突出损伤为淋巴细胞的广泛崩解;肝脏损伤则较轻微。本文对各脏器病变进行了分析,认为心肌对雷公藤具有较高的敏感性,中毒剂量雷公藤对重要免疫器官脾脏有明显的损伤作用。     

大白鼠心脏缺血后再灌流的心肌收缩性能变化和心律失常

健康雄性Wistar犬鼠40只,全麻,开胸后结扎左冠状动脉主支5分钟,然后将动物随机分为两组,缺血—再灌注组(n=24)解除结扎后再继续观察10分钟,持续缺血组(n=16)连续观察15分钟,在冠脉结扎前后及解除结扎后,动态观察有关心功能指标和心电图。 结果发现:结扎左冠状动脉主支后,LVSP和±dp/dtmax立即显著降低,LVEDP立即显著升高,与结扎前各数值比较有显著性差异,但在以后持续结扎的5和15分钟内,未发生进一步变化;解除结扎的动物,上述各项指标突然显著恶化,多数动物发生严重心律失常,与持续结扎的动物比较有显著性差异。 上述结果提示:大白鼠心脏缺血后冠脉血流再通时,可发生严重的心肌损害,心肌收缩性能指标和心律失常能较好地反映这种损害的发生。     

Effects of myocardial revascularization on regional thallium-201 uptake and systolic function in regions with reverse redistribution on tomographic thallium-201 imaging at rest in patients with chronic coronary artery disease

Objectives  There is growing evidence that myocardial segments with reverse redistribution are viable in patients with chronic coronary artery disease. The aim of this study was to assess the effects of myocardial revascularization on systolic function and thallium-201 uptake in such segments. Methods  Rest-redistribution thallium-201 tomography before and after myocardial revascularization was performed in 47 patients with chronic coronary artery disease. Regional function was evaluated by two-dimensional echocardiography before and after revascularization according to a 3-point scale (1=normal, 2=hypokinetic, 3=a/dyskinetic). Improvement of dysfunctional segments was defined when systolic function score decreased ≥1 after revascularization. Reverse redistribution was defined as ≥8% decrease in relative thallium-201 uptake between rest and redistribution images. Results  Reverse redistribution was found in 27 (57%) of 47 patients, corresponding to 60 (11%) of 564 myocardial segments. Of such segments, 24 (40%) had normal systolic function, 19 (32%) were hypokinetic, and 17 (28%) were a/dyskinetic. Thirty-six segments underwent myocardial revascularization, and reverse redistribution was no longer present in 86% of them subsequent to the procedure. Of 26 dyssynergic segments with reverse redistribution subjected to revascularization, 18 (69%) improved at follow-up. Conclusions  The findings of the present study indicate that reverse redistribution is a reversible phenomenon and is often associated with improvement of systolic function following revascularization in patients with chronic coronary artery disease.     

Dynamic changes of myocardial nitric oxide formation and cGMP content in the early stage after radiation, burn and combined radiation-burn injuries in rats

Nitricchide(NO)ispresentinmanyhssuesandactSasap~crineautocoidandintracellularchemicalmessenger.NOiss}vithesizedfromL--argininebynitricoxidesynthase(NOS).TwOmaintYPesofNOShavebeenidentified:aconstitutiveCab -calmedulindependentNOS(cNOS)andaCab independentNOS(iNOS)whichareexpressedafterthestimulationofendotoxinandceTtaincytoki...[IJ.RecentstudiesdemonstratedthatNOalightplayaroleinthemaculationofmyocdriialcontractility.TheactivityofbathcNOSandiNOSisidentifiedinisolatedeardialmyocy…     

Improved coverage in dynamic contrast-enhanced cardiac MRI using interleaved gradient-echo EPI

An interleaved gradient-echo echo-planar imaging (IGEPI) sequence was modified for and applied to dynamic contrast-enhanced imaging of the heart. Using IGEPI, images with 3.0 × 3.9 mm nominal in-plane resolution are acquired in 100 ms, enabling eight slices per heartbeat for a heart rate of 60 beats/min. The acquisition speed and use of saturation pre-pulses allows acquisition of short- and long-axis images during the same contrast bolus. IGEPI maintains the acquisition characteristics required for performing a quantitative first-pass perfusion analysis as well as providing improved coverage compared with conventional fast gradient echo.     

Evaluation of Postinfarction Viable Myocardium at Jeopardy by Dobutamine Echocardiography and Myocardial Contrast Echocardiography

Both myocardial contrast echocardiography (MCE), obtained by intracoronary injection of sonicated Ioxaglate, and dobutamine echocardiography (DE) were performed before and after percutaneous transluminal coronary angioplasty (PTCA) in a patient with recent myocardial infarction, an occluded infarct related artery (IRA) and collateral flow. An opposite response to low and high dose dobutamine (increase and decrease in regional contractility, respectively) suggested the presence of viable myocardium at jeopardy in the infarcted area. This myocardial area was exclusively perfused by collateral circulation (demonstrated by MCE) supplied by an angiographically normal left coronary artery. After PTCA, right coronary artery flow was re-established and angiographically demonstrated collateral flow disappeared. MCE showed a normal right coronary artery perfusion bed and relevant overlap areas after left coronary MCE injection. Dobutamine echocardiography performed after PTCA demonstrated persistence of viability, but disappearence of myocardial ischemia.     

乳猪心肺转流模型的实验研究

在新生乳猪上复制了心肺转流模型，并应用微机软件ＭＢＰ１１多道生理分析系统比较２种未成熟心肌保护方案。结果证明，氨基酸强化温血诱导／再灌注保护方案在维护乳猪心肌收缩功能、心肌细胞膜完整和冠状动脉内皮功能及抗氧自由基损伤方面均优于冷晶体保护方案，表明微机辅助乳猪心肺转流模型是研究未成熟心肌保护的有效工具。     

Detection of viable myocardium with p-iodophenyl-9-(R,S)-methylpentadecanoic acid in ischemic rat myocardium

BACKGROUND: The methyl-branched free fatty acid analog 15-(p-iodophenyl)-9-(R,S)-methylpentadecanoic acid (9MPA) is metabolized more rapidly than 15-(p-iodophenyl)-3(beta)-(R,S)-methylpentadecanoic acid. This study investigates whether myocardial ischemic injury to beta-oxidation and viable myocardium can be detected with the use of 9MPA in a rat myocardial ischemia model. METHODS AND RESULTS: In the acute study the left coronary arteries were occluded for 15 or 45 minutes and then reperfused; the rats were killed after 2 hours. Iodine 125 and iodine 123 9MPA was injected 60 minutes (delayed images) and 3 minutes (early images), respectively, before the rats were killed. In the subacute study the left coronary arteries were either occluded for 45 minutes and then reperfused or occluded and not reperfused. One week later, I-125 and I-123 9MPA was injected 60 minutes and 3 minutes, respectively, before the rats were killed. The distribution of 9MPA was examined with the use of dual-tracer autoradiography. In the acute study the delayed images showed a higher uptake in viable regions at risk than in normal areas and nonviable regions. In the subacute study a difference in uptake between viable regions at risk and normal areas was visible on the early images, but this difference disappeared on the delayed images. CONCLUSIONS: 9MPA is a useful tracer for detecting viable regions of ischemic myocardium during acute and subacute disease stages.     

急性重度低压缺氧对大鼠心肌脂质过氧化与心肌酶活性的影响

为了观察急性重度低压缺氧对心肌脂质过氧化及心肌酶学的影响，对３９只成年健康Ｗｉｓｔａｒ大鼠急性低压缺氧实验。结果发现，急性缺氧后心肌组织中硒谷胱甘肽过氧化物酶（ＳｅＧＳＨｐｘ）活性明显降低，丙二醛（ＭＤＡ）含量减少，ＳｅＧＳＨｐｘ／ＭＤＡ比值下降。结果提示，急性低压缺氧后，心肌组织中的脂质过氧化反应并无明显增强，仅有心肌的潜在抗氧化能力降低。另外，急性低压缺氧后，心肌酶活力显著增高，说明急性低压缺氧对心肌有一定损伤作用。鉴于心肌脂质过氧化反应无明显增强，提示心肌损伤与脂质过氧化无明显相关。心肌酶活力增高的原因，可能是急性缺氧对心肌细胞直接作用的结果。