Intracerebral distribution of albumin after transient cerebral ischemia: light and electron microscopic immunocytochemical investigation

Summary The blood-brain barrier breaks down following cerebral ischemia, but the exact sequence of events for extravasation of serum proteins and their parenchymal distribution remain uncertain. We studied the distribution of serum albumin in the hippocampus of the gerbil brain using light and electron microscopic immunocytochemical techniques. With light microscopy, there was no reaction for albumin for the first 12 h after unilateral common carotid artery occlusion for 10 min and reperfusion. At 12 h, the reaction was weak and limited to the neuropil in the subiculum-CA1 region (between the subiculum and the medial CA1 region). After 24 h, the reaction became intense in the neuropil and neuronal perikarya in the subiculum-CA1 and medial CA1 regions. The electron microscopic immunocytochemical study of the subiculum-CA1 and medial CA1 regions revealed electron-dense immunoprecipitates in the extracellular space and the peripheral part of the apical dendrites as early as 30 min after reperfusion and in the astrocytic cytoplasm after reperfusion for 1 h. However, immunoprecipitates were not found in the neuronal perikarya until after reperfusion for 24 h. The present study demonstrated prompt appearance of albumin in the extracellular space of the brain parenchyma after re-establishment of cerebral circulation and prompt accumulation in the peripheral part of the dendrites with spreading to neuronal perikarya, likely in the process of degeneration and death.Supported by the grant NS-06663 from the National Institutes of Health, U. S. Public Health Service     

Inhibition of glutamate release in rat hippocampus by kynurenic acid does not protect CA1 cells from forebrain ischemia

We assessed the effect of a broad spectrum glutamatergic receptor antagonist, kynurenic acid (500 mg/kg) on ischemia-induced hippocampal glutamate release and neuronal damage. Kynurenic acid significantly decreased glutamate release during ischemia but had no effect on the hippocampal lesion. Some protection was observed in the cortex and in the striatum. These data suggested that the extracellular accumulation of glutamate during forebrain ischemia does not play a major role in the hippocampus.     

小鼠低温游泳脑缺血模型的建立及在注射液量效关系上的应用

目的:建立一种新的脑缺血小鼠模型,用标准的注射液验证模型的可靠性。方法:小鼠分成3组:生理盐水组,尼莫地平组(1.0 mg/kg)和三七总皂苷组(120 mg/kg)。静脉注射25m in后,动物负重5%体重,在10~10.5℃的水中游泳5m in,取出,断头,记录断头的喘气持续时间。小鼠分别注射尼莫地平0.3、0.7、1.0、1.5 mg/kg或三七总皂苷60、80、120、160 mg/kg,同上法操作,探讨两种药物的量效关系。结果:和生理盐水组比较,两个药物能显著延长小鼠断头的喘气持续时间(P<0.01)。尼莫地平的量效关系方程式为:y=27.74919x 18.79446;三七总皂苷的量效关系方程式为:y=0.13347x 20.51017,二者的量效关系均显著(P<0.05,P<0.01)。结论:新的方法能够用于评价药物的抗脑缺血作用。     

心肌缺血大鼠血浆8-异前列腺素F2α水平及N-乙酰半胱氨酸干预作用

目的分析实验性心肌缺血大鼠血浆与心肌8-异前列腺素F2α(8-iso-PGF2α)水平相关性,以及抗氧化剂N-乙酰半胱氨酸(NAC)的治疗效果,探讨血浆8-iso-PGF2α反映心肌氧自由基损伤程度和干预效果的可能性。方法45只Wistar大鼠分为三组:缺血组、缺血 NAC组和对照组。使用垂体后叶素建立大鼠急性心肌缺血模型,以心电图上ST段的抬高作为心肌缺血指标。在缺血 NAC组,预先用NAC 0.1 g/kg·d灌胃3周。应用ELISA方法测定心肌缺血及正常大鼠血浆及心肌组织8-iso-PGF2α含量。结果(1)急性心肌缺血组大鼠的血浆和心肌组织8-iso-PGF2α含量分别为(187.1±45.8)pg/ml和(259.3±47.5)pg/g,明显高于正常对照组的(60.4±13.7)pg/ml和(88.6±16.9)pg/g(P<0.01);(2)急性心肌缺血前应用NAC组的血浆和心肌组织8-iso-PGF2α含量分别为(88.2±16.4)pg/ml和(109.4±24.7)pg/g,明显低于缺血组(P<0.01);(3)血浆与心肌8-iso-PGF2α水平间存在正相关(r=0.856,P<0.01);(4)与正常组比较,缺血组的心电图ST段明显抬高[心肌缺血45 min时抬高最为明显,达(0.34±0.05)mV](P<0.05),心肌缺血前使用NAC,可使心肌缺血得以改善[心肌缺血45 min时心电图ST段仅达(0.18±0.05)mV]。结论急性心肌缺血时8-iso-PGF2α含量产生增加;血浆8-iso-PGF2α可反映心     

红花注射液治疗冠心病心绞痛、心肌缺血临床观察

目的:观察红花注射液治疗冠心病心绞痛、心肌缺血的临床疗效。方法:选择126例冠心病心绞痛、心肌缺血的病例,分红花组及丹参组,疗程两周,详细记录治疗前后的临床表现、心电图、血糖、血脂、血液流变学检查的变化。结果:红花、丹参均可明显改善冠心病心肌缺血相应的临床症状和心电图改变,以红花较显著。红花还有降血糖、血脂作用,显著改善血液流变指标。结论:红花注射液是治疗冠心病心绞痛、心肌缺血的理想药物。     

Imaging of acute mesenteric ischemia using multidetector CT and CT angiography in a porcine model

Acute mesenteric ischemia, a frequently lethal disease, requires prompt diagnosis and intervention for favorable clinical outcomes. This goal remains elusive due, in part, to lack of a noninvasive and accurate imaging study. Traditional angiography is the diagnostic gold standard but is invasive and costly. Computed tomography (CT) is readily available and noninvasive but has shown variable success in diagnosing this disease. The faster scanning time of multidetector row CT (M.D.CT) greatly facilitates the use of CT angiography (CTA) in the clinical setting. We sought to determine whether M.D.CT-CTA could accurately demonstrate vascular anatomy and capture the earliest stages of mesenteric ischemia in a porcine model. Pigs underwent embolization of branches of the superior mesenteric artery, then imaging by M.D.CT-CTA with three-dimensional reconstruction protocols. After scanning, diseased bowel segments were surgically resected and pathologically examined. Multidetector row CT and CT angiography reliably defined normal and occluded mesenteric vessels in the pig. It detected early changes of ischemia including poor arterial enhancement and venous dilatation, which were seen in all ischemic animals. The radiographic findingsd—compared with pathologic diagnosesd—predicted ischemia, with a positive predictive value of 92%. These results indicate that M.D.CT-CTA holds great promise for the early detection necessary for successful treatment of acute mesenteric ischemia. Presented at the Forty-Sixth Annual Meeting of The Society for Surgery of the Alimentary Tract, Chicago, Illinois, May 14–18, 2005 (oral presentation). Supported by the Karin Grunebaum Research Fellowship, Harvard Medical School (D.E.R.), the German Research Fellowship, German Research Foundation STR 690/1-1 (O.S.), and the Phillip H. Meyers Grant from the Society of Gastrointestinal Radiologists (S.P.T.).     

~(99m)Tc-MIBI心肌灌注显像结合门电路心血池显像对高血压患者心肌缺血诊断的评价

本文对40例住院高血压患者作了静息相及负荷相99mTc－MIBI心肌单光子发射计算机断层（SPECT）显像并采用门电路心血池显像（MGBP）评价室壁运动。结果显示：本组病例心肌灌注显像放射性稀疏缺损（MPD）发生率高达87．5％（35／40），其中可逆性（RPD）57．1％；有MPD者在MPD节段室壁运动异常发生率91．4％（32／35），但RPD组与非RPD组间无显著差异。文中对高血压患者心肌缺血及其导致MPD的机制进行了探讨，认为99mTc－MIBI心肌SPECT显像出现MPD是反映高血压患者心肌缺血的敏感方法，MGBP多指标评价室壁运动可揭示绝大多数MPD节段的室壁运动异常。     

血管内支架成形术治疗颅内动脉狭窄

目的:探讨颅内动脉狭窄血管内球囊支架成形术的可行性、安全性及其疗效。方法:17例患者术前3天给予阿司匹林300mg/天和噻氯吡啶250mg/天,6F(Envoy)导引导管放置到颈内动脉远段或椎动脉近颅底段,造影获得工作位,评价血管狭窄程度:狭窄率=(1-狭窄处管径/狭窄远端管径)×100%,微导丝在路途导引下通过颅内动脉狭窄段,向远端直至P2或M2段,确保足够的支撑力。选择支架大小的依据为狭窄远端正常血管的直径,导丝引导下支架通过狭窄部位,造影确定支架位置正确,充盈球囊至5～6大气压,支架释放后造影确认展开良好,回撤球囊,无并发症,操作完毕。随访3～10月。结果:17例患者颅内动脉狭窄处植入支架,技术成功100%,造影显示狭窄由术前(78.3±12.9)%降至术后(6.8±7.3)%,狭窄的动脉管径恢复,短期随访(3～10个月)显示很好临床效果。术中出现一例蛛网膜下腔少量出血(SAH),对症治疗痊愈。6例随访造影未见血管再狭窄。结论:颅内动脉狭窄支架植入增加血管内径,改善血流量,减轻临床症状,是一种安全、可行有效的治疗方法。     

Mental stress-induced myocardial ischemia in coronary artery disease patients with left ventricular dysfunction

Background  Reduced left ventricular ejection fraction (LVEF) is a risk factor for poor outcomes in patients with coronary artery disease (CAD). Mental stress-induced myocardial ischemia (MSIMI) also identifies a subset of CAD patients at increased risk for future cardiovascular events. Susceptibility to MSIMI in patients with CAD and reduced LVEF is unknown. Methods and Results  We enrolled 182 patients (67 women) with a mean age of 64 years and a documented history of CAD in this study. Baseline resting ejection fraction was determined by use of technetium 99m sestamibi gated single photon emission computed tomography. Abnormal LVEF was defined as less than 45% for men and less than 50% for women (based on published norms for our software [Cedars-Sinai Medical Center]). All participants underwent mental stress testing with a public speaking task. Rest/stress myocardial perfusion single photon emission computed tomography was performed via conventional methodology. Images were visually compared for number and severity of perfusion defects by use of a scoring method from 0 to 4. A summed difference score was calculated as the difference between summed stress and rest scores. A score of greater than 3 was considered abnormal. MSIMI developed in 19% of patients with normal LVEF and 31% of those with reduced LVEF. There is no statistically significant difference between the two groups (P=.11). Conclusions  CAD patients with left ventricular dysfunction are equally susceptible to MSIMI as those with normal LVEF. This study was supported by grants HL 070265 and HL 072059 from the National Heart. Lung, and Blood Institute. This material is also the result of work supported by resources and with the use of facilities at the Department of Veterans. Affairs Medical Center, Gainesville, Fla.     

大鼠脑干缺血模型制备及早期超微结构观察

目的:制备脑干缺血动物模型并观察大鼠脑干缺血后早期组织学病理的超微结构。方法:应用两点电凝基底动脉的方法制作鼠脑干缺血动物模型。结果:病理学观察发现脑干缺血2小时即可出现超早期病理变化,并随时间的延长缺血性损害逐渐加重。结论:两点电凝基底动脉后可以造成稳定的脑干缺血,对急性脑干缺血的病理学研究有一定的价值。