Transcranial Doppler and Microemboli Detection: Relationships to Symptomatic Status and Histopathology Findings

The purpose of this study was to determine the relationship between symptomatic status, transcranial Doppler (TCD) microemboli presence and plaque histopathology findings. TCD was performed on 60 patients (37 symptomatic, 23 asymptomatic) before undergoing clinically indicated carotid endarterectomy. The frequency of microemboli signals was not significantly different between symptomatic and asymptomatic subject groups (p = 0.88) and there were no differences observed in the macroscopic or histopathology scoring of these plaques (p-values all > 0.05). The presence of microemboli was associated with an ulceration score (regardless of symptomatic or asymptomatic status, p = 0.034), with a one-level increase in ulceration rating associated with an odds ratio of 5.86 (95% [CI] 1.55, 43.4). These findings suggest that both symptomatic and asymptomatic patients may have plaque with similar features of instability and ability to create emboli. Thus, identifying new ways to measure plaque instability may provide important information for optimizing treatment to prevent future stroke.     

脑动脉微栓子对APP／PS1双转基因小鼠脑星形胶质细胞活化和神经元凋亡的影响

目的建立APP／PS1双转基因叠加脑梗死阈值下脑动脉微栓子的小鼠模型,进一步探讨脑梗死阈值下脑动脉微栓子对阿尔茨海默病的神经损伤叠加机制。方法将实验动物分为野生型小鼠对照组（n=12）,APP／PS1双转基因小鼠假手术组（n=12）和APP／PS1双转基因小鼠叠加微栓子组（n=12）,微栓子组经左侧颈内动脉注入25-50μm大小的全血凝块微栓子100个／300μL,假手术组和对照组注入等量的生理盐水,造模后3d和7d,HE染色观察有无梗死灶,TUNEL染色检测神经细胞的凋亡,GFAP免疫组化检测星形胶质细胞的激活。结果3组小鼠HE染色均未发现缺血梗死灶,脑梗死阈值下微栓子模型造模成功。凋亡细胞阳性率和GFAP表达阳性细胞数,对照组〈假手术组〈微栓子组,3组两两比较有统计学意义（P〈0．001）;并且在微栓子组,凋亡细胞和GFAP阳性表达随着时间的延长而增加,7d组较3d表达更多,差异有统计学意义（P〈0．001）。结论脑梗死闯值下的微栓子,虽未导致脑梗死,但可以促进APP／PS1双转基因小鼠脑胶质细胞的激活,诱发并加重AD的炎症反应进程,促进神经细胞凋亡。     

The Positions of the Patients in the Diagnosis of Patent Foramen Ovale by Transcranial Doppler

BACKGROUND AND PURPOSE: There is no information about the optimal position of a patient for the performance of a transcranial Doppler (TCD) examination to detect patent foramen ovale (PFO). Such information is important to improving the sensitivity of the test in comparison to the gold standard of transesophageal echocardiography (TEE). METHODS: Thirty-four patients with TEE-proved PFO were examined by contrast TCD. Examinations were done in both the sitting and supine positions in random order. RESULTS: Eight hundred ninety-two microemboli were recorded. Patients' positions and the sequence of testing did not affect the number of microemboli detected. Yet for each individual, 1 of the 2 positions was more sensitive. CONCLUSIONS: To improve the sensitivity of TCD in the detection of PFO, it is recommended, in the case of a first negative test, to change the patient's position for a repeated TCD examination.     

Magnevad--the world's smallest magnetic-bearing turbo pump

The first animal implant of our Magnevad LVAD is scheduled for the fourth quarter of 2003. This is being performed by the George E. Reed Heart Center of Westchester Medical Center and by New York Medical College; both are in Valhalla, NY. This article summarizes 3 years of development of the miniature axial flow LVAD. Our LVAD has new innovations not found in any other turbo pump to minimize thrombus, blood turbulence, flow separation, and the generation of microemboli. The Magnevad is only 25 mL in volume, similar in size to the Micromed & Jarvik 2000 axial flow turbo pumps that have contacting bearings. US Patent 6 527 699 was issued to Gold Medical on March 4, 2003 and World Wide PCT patents are pending. The discussed improvements (patents pending) are designed to minimize flow separation and turbulence, the precursors of microemboli that lodge in end organs. This problem has been largely ignored in the published literature. A new long-term stable miniature ultrasonic position sensor is used for bearing control. It measures the axial position of the rotor to obtain LVAD differential pressure. Differential pressure is used to obtain pulsating flow and automatic physiologic control. The term "fourth generation pump" is being coined for the Magnevad because in addition to being noncontacting, it inherently measures pump differential pressure on which physiologic control can be based.     

急性脑梗死合并2型糖尿病患者微栓子与血清脂蛋白相关磷脂酶A2的关系

目的探讨急性脑梗死合并2型糖尿病患者微栓子与血清脂蛋白相关磷脂酶A2(LpPLA2)的关系。方法选择2017年9月至2019年5月我院收治的120例急性脑梗死患者,根据有无糖尿病分为有2型糖尿病的DACI组(50例)和无2型糖尿病的NDACI组(70例)。对所有患者完善相关临床检查,比较两组的血清LpPLA2水平和微栓子信号阳性率。结果DACI组的血清LpPLA2水平为(442.2±67.4)μg/L,高于NDACI组的(324.1±54.9)μg/L,差异有统计学意义(P<0.05)。DACI组的微栓子信号阳性率为92.00%,高于NDACI组的68.57%(P<0.05)。结论急性脑梗死合并2型糖尿病患者的血清LpPLA2水平及微栓子信号阳性率均较高,表明血清LpPLA2与微栓子信号阳性是引起急性脑梗死合并2型糖尿病的危险因素。     

大脑中动脉近端支架成形术中的微栓子监测

目的 应用经颅多普勒超声（TCD）监测大脑中动脉（MCA）近端狭窄支架成形术中的微栓子信号。方法 2006年1～12月成功进行MCA近端狭窄支架成形术的8例（女3例,男5例,平均年龄45.5±10.5岁）。将手术过程分为4个阶段：（1）导引导管置放阶段;（2）微导丝置放阶段;（3）支架输送阶段;（4）球囊扩张阶段。同步记录手术中各阶段TCD监测到的MCA远端微栓子数目,记录支架成形术前和术后即刻狭窄处收缩期峰值血流速度（Vs）。结果 本组病例无手术相关并发症。术前狭窄率为79.4％±7.8％,术后降至9.4％±8.2％,P＜0.01。MCA近端狭窄处Vs术前305.3±61.5 cm/s,术后即刻为201.1±40.5 cm/s,P＜0.01。4个阶段均可监测到微栓子信号,分别为3.5±4.2、8.9±7.2、4.6±5.8及14.5±7.0（P＜0.01）,以第4阶段为著。结论 支架成形术可以改善动脉粥样硬化性MCA狭窄,增加狭窄远端脑组织血流供应。术中各个阶段都能监测到微栓子信号,但术中微栓子脱落与术后缺血性卒中事件的相关性有待于进一步研究。     

伴有颈动脉斑块的急性前循环脑梗死患者的微栓子研究

目的 探讨颈动脉斑块、微栓子和急性前循环脑梗死的关系。方法 选择住院的急性前循环脑梗死患者65例,经颈动脉超声检查分为伴有颈动脉斑块组45例和不伴有颈动脉斑块组20例,2组均行微栓子监测。结果 伴有颈动脉斑块组与不伴有颈动脉斑块组吸烟、高血压病、糖尿病、高脂血症相比无明显差异(P>0.05); 伴有颈动脉斑块患者的微栓子阳性率为38%,不伴有颈动脉斑块患者为13%,2组相比有明显差异(P<0.05); 软斑组微栓子阳性率为45%,硬斑组微栓子阳性率为18%,2组相比有明显差异(P<0.05)。结论 急性前循环脑梗死患者多有颈动脉斑块,软斑块是微栓子的主要来源,微栓子是急性脑梗死发病的重要危险因素,对二者早期干预是防治脑卒中的重要措施之一。     

脑动脉微栓子诱发非梗死性脑损伤大鼠模型的建立

目的为探讨脑动脉微栓子的神经损伤机制,建立脑梗死阈值下脑动脉微栓子诱发脑损伤的大鼠模型。方法24只SD大鼠随机分为微栓子组和假手术组。造模后,每组又分为3d和7d组,每组6只大鼠。经左侧颈内动脉分别注入25～50μm大小的全血凝块微栓子100个／300μl或等量的等渗盐水。于造模后3d和7d,采用HE染色观察有无梗死灶、TUNEL染色和Caspase-3蛋白免疫组化染色定量分析神经细胞凋亡的变化。结果微栓子组和假手术组所有大鼠HE染色未发现缺血梗死灶。TUNEL染色显示假手术组仅见少量凋亡细胞,而微栓子组凋亡细胞数量明显增多（P〈0．001）,并且随时间的延长而明显增加,7d组较3d组更明显（P〈0．001）。蛋白免疫组化染色显示,假手术组仅见零星Caspase-3蛋白阳性表达,而微栓子组明显增加（P〈0．001）,并且7d组比3d组更明显（P〈0．001）。结论25～50μm的全血凝块微栓子以100个／300μl的浓度缓慢注入到大鼠颈内动脉,不一定能造成脑梗死,但可以导致神经细胞凋亡。     

微栓子与缺血性卒中的研究进展

微栓子是在血流中通过的除正常血细胞外的其他异常成分,这些异常物质可以被经颅多普勒（transcranial doppler sonography,TCD）实时监测到。微栓子的出现极大提示存在不稳定的动脉粥样硬化斑块,会导致颅内远端小血管动脉到动脉的栓塞。本文就微栓子与缺血性卒中的病因、神经系统功能的损害、血液内相关成分的关系、斑块的性状、治疗及预后相关问题的最新知识进行了总结,另外还关注了微栓子的新特点与监测新方法、微栓子与其他疾病的关系。