一种甚高频超声仿血液流速测量系统的实验研究

目的设计并实现一种甚高频超声仿血液流速测量系统,用来完成模拟人体浅表器官血流信息实时检测的实验研究。方法笔者自制了血液仿体,该仿体由尼龙颗粒、纯净水、甘油、葡聚糖和非离子表面活性剂组成。该系统实验平台包含控制流速的医用注射泵、医用硅胶管和模拟血液仿体所组成的模拟血液循环系统;工作频率为50 MHz的单脉冲、机械、线性扫描探头;下位机超声回波信号采集电路和上位机模块构成的甚高频超声血流成像系统。将换能器置于模拟血管上方9 mm左右处,血液流动方向与探头扫查方向相向,调整注射泵的推动速度,得到焦点区域附近的模拟血液成像。结果笔者自制的血液仿体的声学特性在150 d内几乎没有改变,符合实验研究要求。由不同流速仿血流成像结果图可见,当流速较低时,红细胞成像颗粒较大,数量较少;当流速较高时,红细胞成像颗粒较小,数量较多。结论设计的甚高频超声仿血液流速测量系统可以初步得出模拟血流红细胞成像颗粒数值与模拟血流流速成正比,并由此判定血流流速的快慢。     

微血管内红细胞的流速及白细胞对血流的调节作用

血流速度的测量是微循环研究最主要的参数之一。本实验采用30-1000幅/秒超高速显微摄像录像技术,记录及测量了正常大鼠肠系膜微循环申细动脉、毛细血管、细静脉的血流速度。8只大鼠微血管的内径从4μm—40μm的血管120根,细动脉直径最大25μm,血流速度平均5.86±0.76mm/秒。随着血管直径的减小,血流速度明显减慢,在4—6μm的毛细血管内红细胞的流速平均2.29±0.9mm/秒。在40μm直径的细静脉血流平均2.8±0.8mm/秒,比毛细血管的流速快。白细胞在微血管内流动时其流速和红细胞相同,白细胞贴附在血管壁上滚动时。速度从0.16-0.74mm/秒。白细胞贴壁不再滚动时,有的会穿过血管壁而游走到血管周围的组织,白细胞贴壁数量增多时,可使管腔变小。     

小鼠脑微循环研究的方法——封闭式颅窗法

目的 :介绍一种新的观察脑微循环的技术。方法 :在猫、鼠脑封闭式颅窗的技术基础上 ,试用小鼠安装脑颅窗 ,在显微镜下观察微循环的变化。根据观察目的不同 ,可利用其生理特点选择不同型的小鼠。实验中严格控制动脉血PaO2 和PaCO2 ,同时利用荧光标记的方法 ,将血管管径及红细胞流速做图像定量分析。结果 :利用此方法可以得到清晰的血管及血流图像。操作步骤简单 ,减少生理上的损伤。结论 :选择小鼠安装脑颅窗 ,并以此达到观察微循环的目的 ,是可选择的方法。操作上的难易程度对有经验的研究人员是完全可以胜任的     

大鼠动脉螺旋血流的荧光成像

目的 建立大鼠动脉螺旋血流的实时荧光成像法。方法 随机将SD大鼠分为静脉造影组(股静脉注射,1 mL/kg)与小剂量动脉造影组(腹主动脉注射,0.1 mL/kg),其中小剂量动脉造影组又分为荧光素钠组、罗丹明B组、FITC-dextran组和量子点组(每组n=7)。通过体式荧光显微镜实时观察大鼠股动脉血液流动现象,用高速摄像机拍摄动态图像,通过图像阈值分割算法及形态学后处理算法标定荧光区域,测算大鼠股动脉螺旋血流的轴向速度与切向速度,并计算其螺距和壁剪切应力。结果 与静脉造影组相比,小剂量动脉造影组可以清晰显示大鼠股动脉的血流呈顺时针螺旋样流动,在FITC-dextran造影剂组可计算出大鼠螺旋血流的轴向速度为(198.4±112.7)mm/s,切向速度为(3.3±0.8)mm/s,螺距为(126.1±76.3)mm,壁剪切应力为(9.5±5.6)Pa。每只大鼠重复3次注射,测得的轴向、切向速度结果无差异。结论 实时荧光成像法可以用于在体观察大鼠动脉螺旋血流并对螺旋血流的血流动力学特征进行定量分析。     

糖尿病大鼠红细胞对脑组织损伤的影响

研究糖尿病时红细胞的变化对脑组织损伤的影响。方法：用链脲佐菌素（ＳＴＺ,５０ｍｇ／ｋｇ）诱发大鼠糖尿病,分离红细胞,输注给正常大鼠（８×１０９个红细胞／只）,测定脑组织ＭＤＡ和亚硝酸盐含量,同时将分离红细胞在体外用异硫氰酸荧光黄（ＦＩＴＣ）标记,荧光显微镜观察输入的红细胞在脑微血管中的流动。结果：ＳＴＺ大鼠血糖持续高于正常,病程达一年的大鼠糖基化血红蛋白（％）明显高于正常大鼠（Ｐ<０．０１）。将糖尿病１年大鼠红细胞输给正常大鼠,４ｈ后,糖尿病红细胞组大鼠脑组织ＭＤＡ和亚硝酸盐含量明显高于对照红细胞组（ＭＤＡＰ＝０．０３２;亚硝酸盐Ｐ＝０．０２７）。软脑膜微循环的活体观察发现有ＦＩＴＣ标记的糖尿病红细胞粘附于微血管壁。结论：糖尿病的红细胞可以直接引起正常脑组织自由基代谢产物的变化,其作用可能与红细胞对内皮细胞的粘附有关。     

脂肪肝对小鼠肝血窦内血流状况的影响

目的 由于脂肪肝状态下肝细胞的体积变化可能导致肝内血液流动特征改变,本研究拟通过观测肝内的形态学、血流速度和迂曲度的变化,为脂肪肝的诊治提供帮助。 方法 小鼠背部皮下注射四氯化碳或橄榄油溶液建立脂肪肝模型,取小鼠肝组织进行HE与油红O染色;采用激光多普勒仪测量肝左叶浅表血管内的血流速度;小鼠尾静脉注射德克萨斯红荧光染料,双光子荧光显微镜下观察及测量小鼠肝血窦内红细胞的流动速度及血管内径状况,并进行肝血窦迂曲度检测。 结果 给予小鼠四氯化碳注射2周（n=16）和4周（n=16）后,油红O染色可见肝细胞内出现不同程度的红色脂滴沉积,且主要集中在中央静脉周围,肝血窦存在明显的变形和缩窄,且4周组更加明显。随着模型制作时间的延长,肝左叶的的浅表区域和肝血窦内的血流速度逐渐降低,且肝血窦的内径变小,迂曲度增加。 结论 脂肪肝状态下,肝血窦内径减小,血窦内血流速度下降,迂曲度增加,为脂肪肝早期诊断和治疗提供了可视化的形态学实验依据。     

基于体外实验和数值仿真的冠脉介入手术中球囊去充盈瞬间的血流动力学研究

目的研究冠脉介入手术中血流参数在球囊去充盈瞬间发生的动态变化,探讨球囊去充盈对术后无复流发生风险的潜在影响。方法搭建体外实验装置,利用高速摄像机拍摄球囊变形过程和由染色剂标记的流场(流体介质为水),使用图像分析技术提取球囊变形参数,并估测球囊下游的流体流动速度;构建计算机仿真模型,导入实测的球囊变形数据,在多种灌注压和流体介质条件下模拟球囊去充盈过程。结果球囊在去充盈过程中呈现显著的非线性变形特征。球囊下游流速的数值计算结果与实测数据吻合良好,两者均显示流速随去充盈后的时间增长和灌注压升高而增大。数值计算进一步揭示,球囊下游流速在接近冠脉血流速度生理值时,球囊-管壁间隙流速和壁面剪应力分别达到其生理值的8~10倍和60~70倍。结论球囊去充盈引起球囊-管壁间隙流体急剧加速和壁面剪应力异常升高,从而增大斑块、血栓碎屑剥离的风险。鉴于壁面剪应力的升高程度随灌注压升高而增大,在冠脉介入手术中采取术前降压或选择舒张期去充盈等措施可能有助于降低无复流的发生风险。     

失血性休克时白细胞附壁粘着机理

用高倍显微放大技术,从细胞流变学变化研究了失血性休克时白细胞粘着于细静脉的机理。20只SD大鼠分为盐水对照组和虎杖治疗组(n=10),制备脊斜肌活体微循环观察标本。用Hitachi牌显微电视录像系统进行观察。用红细胞跟踪相关仪测量血流速度,用电视测微仪测量血管口径,从放大4000倍电视图像上计数60微米     

考虑频谱展宽校正的最大血流速度估计方法

在超声多普勒血流测量中，接收信号的频谱宽度与许多因素有关。除血流的流动特性引起的谱展宽外，测量系统的声学特性的非理想性也会引起附加的频谱展宽。因此，常规的多普勒血流速度估计方法将不可避免地导致最大流速的高估。本文提出了一种考虑固有频谱展宽效应的峰值血流速度估计的校正方法，介绍了该方法的基本原理及校正公式，并且给出了在体实验结果。     

老年大鼠模型视网膜血管改变及视网膜中央动脉血流变化的高分辨率超声图像检测

背景：视网膜对缺血非常敏感,所以眼部血流动力学的改变可直接影响眼的功能,目前评估眼部血液循环可借助多种仪器设备。 目的：应用高分辨率小动物超声影像系统检测视网膜中央动脉的血流动力学变化,结合视网膜血管消化铺片技术检测视网膜血管结构变化,以明确老年大鼠视网膜中央动脉血流动力学的变化规律。 方法：使用高分辨率小动物超声影像系统测量老年大鼠和青年大鼠及视网膜中央动脉的血流参数,包括收缩期峰值血流速度、舒张末期血流速度,计算搏动指数、阻力指数和收缩期舒张期血流速度比值。同时使用视网膜血管消化铺片技术检测视网膜血管形态学改变。 结果与结论：与青年大鼠组相比,老年组大鼠视网膜血管内皮细胞增生,排列紊乱,管径增粗,血管壁不光滑;视网膜中央动脉血流速度、舒张末期血流速度均降低(P < 0.01),计算搏动指数、阻力指数及收缩期峰值与舒张末期血流速度比值则升高(P < 0.01)。说明使用高分辨率小动物超声影像系统检测视网膜中央动脉收缩期和舒张期峰值速度及阻力指数能较敏感地反映血管的老化过程。     

Detection of pulsatile blood flow cycle in frog microvessels by image velocimetry

The detection of pulsatile blood flow velocity through one section of a curved branching frog mesenteric microvessel during a flow cycle, by analysis of a sequence of videomicroscopic images recorded at a frame rate 25 frames s⁻¹, is presented. From these data, 64 sequential digitised frames of 128×128 pixels and 256 grey level were selected. By processing sequential pairs of frames by image velocimetry, the corresponding displacement vector was calculated. Dividing this by the frame rate gave the vector velocity. The same procedure was repeated for all frames, and the corresponding maximum (0.36–0.38 mm s⁻¹), minimum (0.0–0.025 mm s⁻¹) and other velocity values were obtained and plotted. The preliminary data analysis showed that the separation between two velocity maxima was about 20 video frames, which corresponded to one cardiac cycle of time interval 0.8 s.     

32例脑性瘫痪患儿甲襞与耳廓微循环观察

对32例脑性瘫痪患儿甲襞与耳廓微循环进行观察。结果显示:脑性瘫痪患儿甲襞微循环在形态、流态积分值及综合积分值上均高于健康儿;耳廓微循环中微血管畸形发生率及细静脉RBC聚集发生率,脑瘫组均高于健康组,而细静脉流速则脑瘫组明显较健康组减慢;脑瘫患儿耳廓与甲襞微循环中RBC聚集发生率及粒流、粒缓流出现率,耳廓均较甲襞为高,而脑瘫患儿微血管畸形发生率在甲襞与耳廓无显著差异。     

Computerised visualisation from images of blood flow through frog mesenteric microvessels with multiple complexities

Blood flow through a frog mesenteric microvessel, consisting of one loop and two successive bends, was recorded by a video-microscopic system and analysed by a PC-based image processing system. After preprocessing, these images were analysed by the image velocimetry, axial tomography and image processing procedures. The blood flow in the microvessel had a Reynolds number of 0.033, and the Dean number varied from 0.004 in the loop to 0.007 in the bend, showing an increase in secondary flow in the bend region. These changes led to outward shifts in the peaks of velocity and concentration profiles, with an increase in the thickness of the outer walls (of about three times) compared with that of the inner walls. The mean velocity and mean cellular concentration showed a similar pattern. The variation in the cellular concentration in the microvessel was visualised by concentration contours and grey-scale images of the cellular distribution. At the inner wall of the complex geometry, the velocity reduced to zero, whereas the cellular concentration varied from 2 to 5%. In the high shear stress regions in the complex geometry, the vessel wall thickness was two-three times more than that in low shear stress regions.     

新生儿缺氧缺血性脑病的耳廓微循环观察

新生儿缺氧缺血性脑病的耳廓微循环观察阴怀清＊杨彩凤＊王阿琚＊缺氧缺血性脑病（ＨＩＥ）是围产期新生儿最常见的中枢神经系统病变，是由各种原因造成缺氧缺血引起的脑损害。它是导致小儿时期发生脑性瘫痪或智力低下等神经系统后遗症的主要新生儿疾病之一。为探讨ＨＩＥ...     

光化学法致栓模型中血小板血栓生长速度的研究

本文应用光化学方法在大鼠肠系膜微血管内定位建立活体血小板血栓生成模型,通过生物荧光显微电视系统对整个实验过程进行观察和记录。利用视频多媒体系统和自行开发的计算机图象处理系统,对血栓生长的动态过程进行图象的采样、处理和分析,定量测量了血栓开始形成时间、血栓完全栓塞时间,以及归一化后的血栓长度、血栓高度、血管狭窄截面面积、血栓表面积和血栓体积等指标的时变曲线,并对光化学法致栓模型中血小板血栓的生长速度进行了讨论。本文提出的方法使定量描述血栓的动态生长过程成为可能,为客观评价各类病理条件或药物作用条件下的血栓生长情况提供了定量指标和比较依据     

葛根素、川芎嗪、丹参注射液对家兔软脑膜微循环的影响

目的 :探讨葛根素、川芎嗪、丹参注射液治疗脑血管疾病的疗效机制。方法 :采用闭合式颅骨开窗法 ,应用多部位微循环观察仪及微循环计算机图像处理系统 ,观察用药前后家兔软脑膜微血管管径及血流速度的变化。结果 :正常家兔静脉注射葛根素 ( 5 0 mg/kg) ,对微血管的管径及血流速度的影响较小 ;静脉注射丹参注射液 ( 1ml/ kg)、川芎嗪 ( 2 0 ml/ kg)、维脑路通 ( 1ml/ kg)均有扩张微动脉、增加微动脉血流速度的作用 ,对微静脉作用较小。其中丹参注射液作用最为明显。结论 :静脉注射丹参注射液、川芎嗪、维脑路通系通过扩张软脑膜微动脉、增加微动脉血流速度而达到治疗目的。     

Cathodoluminescence imaging for identifying uptaken fluorescence materials in Kupffer cells using scanning electron microscopy

Cathodoluminescence (CL) is the light that is emitted from a material irradiated by an electron beam. The present study was undertaken to show the applicability to biological studies of a scanning electron microscope (SEM) equipped with a high-sensitive cathodoluminescence detection system. For this purpose, we injected inorganic fluorescent powders (P43) suspended in phosphate buffered saline into rat blood circulation, fixed the animals with glutaraldehyde within a day, and observed the hepatic tissues with a SEM. Our instrument enabled the simultaneous collection of both secondary electron (SE) and CL images of these tissues. Backscattered electron (BSE) images of the same portion were also able to be obtained with this microscope. SE and BSE images clearly showed the three-dimensional structure of the hepatic tissues including hepatocytes, Kupffer cells, Ito cells, and sinusoidal epithelial cells, while CL images visualized cathodoluminescence signals emitted from P43 as bright spots. We observed non-coated tissues under a low-vacuum condition and metal-coated tissues under a high-vacuum condition, and found that the high-vacuum observation of metal-coated tissues provided high quality CL images of P43 in the Kupffer cells. The superimposition of the CL images onto the corresponding SE or BSE images revealed that bright spots in the CL images were produced by the fluorescent powders uptaken by Kupffer cells. These findings indicate that the detection of CL as well as SE or BSE signals by SEM all provide us with useful information on the distribution of fluorescent tracers in tissues and cells in three-dimensional images.     

大鼠嗅球乙酰胆碱酯酶阳性传入纤维起源的实验研究

本文应用荧光素逆行标记与乙酰胆碱酯酶(AchE)组织化学相结合技术,探索了嗅球AchE阳性传入纤维的起源。经观察在注射区同侧的下列核(区)可发现荧酶双标记细胞:嗅前核后部、斜角带核、屏状核、中缝背核、中央上核和蓝斑。     

Determination of Red Blood Cell Velocity by Video Shuttering and Image Analysis

A novel modification of conventional video imaging techniques has been developed to determine the velocity of red blood cells (RBCs), which offers compatibility with existing video-based methods for determining blood oxygenation and hemoglobin concentration. Traditional frame-by-frame analysis of video recordings limits the maximum velocity that can be measured for individual cells in vivo to about 2 mm/s. We have extended this range to about 20 mm/s, by electronic shuttering of an intensified charge-coupled device camera to produce multiple images of a single RBC in the same video frame. RBCs were labeled with fluorescein isothiocyanate and the labeled cells (FRBCs) were used as probes to determine RBC velocities in microvessels of the hamster retractor muscle. Velocity was computed as the product of the distance between centroids of two consecutive image positions of a FRBC and the shuttering frequency of the camera intensifier. In vitro calibrations of the system using FRBC and Sephadex beads coated onto a rotating disk yielded an average coefficient of variation of about 6%. Flow conservation studies at bifurcations indicated that the maximum diameter of microvessels below which all the FRBCs in the lumen could be detected was 50 m. The technique was used to estimate mean-FRBC velocity distributions in vessels with diameters ranging from 8 to 50 m. The mean-FRBC velocity profiles were found to be blunter than would be expected for Poiseuille flow. Single FRBCs tracked along an unbranched arteriole exhibited significant temporal variations in velocity. © 1999 Biomedical Engineering Society. PAC99: 8719Tt, 8717Jj, 4279Pw, 8780Tq, 8719Ff, 4230Va, 0705Pj     

CM-Dil标记大鼠骨髓间充质干细胞的生物学特性探讨

BACKGROUND:Existing evidence has shown that CM-Dil-labeled mesenchymal stem cells have delivered better results in experiments in vivo and in vitro. OBJECTIVE:To investigate the effect of in vitro CM-Dil labeling on biological characteristics and directed migration of rat bone marrow mesenchymal stem cells. METHODS:Mesenchymal stem cells were isolated and cultured from the bone marrow of Sprague-Dawley rats. The specific surface antigens, CD29, CD44, CD11b, CD45, were detected by flow cytometry. The rat bone marrow mesenchymal stem cells were labeled with CM-Dil, and then were cultured and passed continually. Thereafter the morphology and proliferation ability of labeled cells were assessed. The strength and duration of fluorescence after CM-Dil labeling were detected. Transwell chambers were used to investigate the migration ability of labeled cells towards the homogenate of the gastrocnemius muscles of mdx mice. RESULTS AND CONCLUSION:The cultured cells were markedly positive for CD29 and CD44, but negative for CD11b and CD45, which were in accordance with the features of bone marrow mesenchymal stem cells. CM-Dil-labeled cells were not different from unlabeled cells in the aspect of morphology and proliferation. Fluorescence was still visible after passage; however, a reduction in fluorescent intensity was observed under an inverted fluorescent contrast phase microscope after labeling. The labeled cells showed no different migration ability from the unlabeled cells (P > 0.05). In conclusion, the procedure of CM-Dil labeling is safe, simple and effective. CM-Dil could be a good choice for labeling and tracing rat bone marrow mesenchymal stem cells.