应佩青;靳刚;陶祖莱
An important goal of cardiac revascularization is to improve the left ventricular ejection fraction ( LVEF), which is an important long - term prognostic clinical indicator for patients with coronary artery disease. Prediction of cardiac function improvement after revascularization would be very helpful for patients with severe left ventricular dysfunction who are at high surgical risk. Our objective is to develop a quantitative method to estimate post -revascularization LVEF prior to revascularization.
作者:Haichao HAN;Stamatios LERAKIS 刊期: 2003年第z1期
切应力可调节细胞的增殖和凋亡,从而影响血管的重建.研究低切应力对完整血管平滑肌细胞原癌基因蛋白c-Fos和c-Myc表达的影响,可以初步探讨切应力引起血管平滑肌细胞增殖和调亡的机制.本文应用血管体外应力培养系统,将一段完整的猪颈总动脉在体外进行培养,控制定常流和血管腔内压力100mmHg,在中(20dyn/cm2)、低(5dyn/cm2)切应力条件下体外培养1、6、24h,采用免疫组化和计算机图象分析方法观察血管壁平滑肌细胞c-Fos和c-Myc表达的情况.
作者:姜宗来;刘艳春;刘波;张峰;张炎 刊期: 2003年第z1期
目的探讨用可降解外套管束缚移植静脉(VG)一段时间,防止VG再狭窄及其生物力学机制.方法以18条犬的股静脉和颈外静脉调转按相同伸长比端-端吻合至同侧股动脉和颈总动脉,其中一侧股动脉和颈总动脉的移植静脉外加可降解外套管为实验组,不加外套管侧为对照组.可降解外套管采用聚乳酸-聚乙醇酸(PL-GA),降解速度6周.
作者:纪广玉;邹良建;张宝仁;韩林;龚克勤;孙辉;柳兆荣 刊期: 2003年第z1期
心脏建模不但具有理论和方法学意义,也具有重要的临床意义,例如,某些临床指标离开了心脏的几何模型将无法计算.在心脏建模中至少存在四个问题:(1)在心脏的几何模型的临床应用中存在着个体化的困难,例如,把具体病人心脏的影象检测数据与理想的几何形状拟合所报告的射血分数值所带来的误差;同时,心脏超声检查心腔体积定量计算研究报告中缺少金标准的选择和对照;(2)在心脏的力学模型方面,心肌收缩能力概念本身至少存在两个严重缺陷,即缺乏能在原位检测而又无可非议的有力指标,特别是缺少可接受的无创性指标,不能区别心肌收缩能力改变与负荷和心率改变在细胞层次上机制,这限制了心脏力学模型的实用性;(3)对不同层次上的心脏模型作生物医学上现实的整合亟待进行,以期对临床心脏病学作出更大支撑;(4)缺少心脏储备建模的研究,而作为心脏病的严重后果的心力衰竭的基本问题正是心脏储备的降低.
作者:肖守中;郭兴明 刊期: 2003年第z1期
非线性动力学的很多指标都曾尝试用于心率变异性(HRV)的分析,如DFA(Peng,1995)、多分维数(Ivanov,1999)、非线性自回归模型(Poon,1997)和同步化(Schafer,1998;Glass,2001)等,而且被证明能用于临床诊断(Gold-berger,1996;2000).但是,关于HRV的混沌特征的机理探讨所见报道甚少,甚至还有相反意见存在(Kanters,1994;Le Pape,1997).而且有一个长期争论的问题是,心率变异性是确定性混沌吗?由于传统的指标如Lyapunov指数、相关维和近似熵等对非平稳性和噪声过于敏感,并不适宜于鉴别HRV是否确定性混沌(Poon,1999).
作者:吴国强;Chi-Sang Poon 刊期: 2003年第z1期
Objective Bone cells, particularly osteoblasts and osteocytes, can detect fluid flow as mechanical signal in situ, transduce the physical stimuli into biochemical signals and integrate these signals into appropriate changes in the architecture of bone. This process, termed mechanotransduction, is the essential cellular mechanism for the bone adaptation. Exposure to weightlessness during space flight may lead to a lower load state of stress, which can induce the osteopenia in crewmembers skeleton system. This study was aimed to explore the effects of weightlessness on mechanotransduction in osteoblasts.
作者:Shu ZHANG;Bing WANG;Xingyu WU 刊期: 2003年第z1期
目的了解骨髓干细胞诱导分化成内皮细胞及在生物材料进行种植的可行性,为血管组织工程提供资料.方法取正常健康人(2~50岁)骨髓,加淋巴细胞分离液,经密度梯度离心后获得单核细胞,再运用微磁珠和单抗选择出CD45和GlyA都为阳性的细胞.用60%低糖DMEM,40%MCDB-201(Sigma),1×胰岛素铁传递蛋白硒,1×linoleic acid bovine serum albumin(BSA),10-9M地塞米松(Sigma),和10-4 M 2-磷酸盐维生素C(Sigma),100 U青霉素,和1000 U链霉素(Gibco).培养.用无血清、EGF or PDGF,含20ng/mL VEGF-B骨髓干细胞培养液培养,分化的细胞通过免疫荧光激光共聚焦检测KDR,vWF,CD34,的表达,以确定是否已分化成内皮细胞.
作者:朱楚洪;应大君;糜建红;董世武;张伟;孙建森 刊期: 2003年第z1期
Leukocytes roll along the endothelium of postcapillary venules in response to inflammatory and thrombotic processes. The rolling under hydrodynamic shear forces is a first step in directing leukocytes out of the blood stream into sites of inflammation and is mediated by the selectins, a family of extended, modular, and calcium -dependent lectin receptors[1,2]. The interactions between P - , E - or L - selectins and their counter ligand P - selectin glycoprotein ligand - 1 ( PSGL - 1 ) play important a crucial role in the processes.
作者:Zhiyi YE;Baoxia LI;Mian LONG 刊期: 2003年第z1期
在大动脉中,动脉粥样硬化疾病首先在腹主动脉处出现,并且在腹主动脉处更为普遍.由于腹主动脉在其横膈膜附近具有很多分支,这些分支将血液输送到腹部的各个器官,因此,这些状况使得腹主动脉的脉动流的研究变得非常复杂.随着医学成像技术的发展,在体模型的血流动力学研究取得了大量的成果,但是该研究方法也有其自身的局限性,即只能在轴向位置上得到相对较少的速度量,然而在整个腹主动脉中,随时间与空间变化的速度场和剪切应力场并不能通过该方法获得.目前,在脉动流的研究中,大量的研究集中于颈动脉分支的研究,而对于腹主动脉而言,数值上的研究相对较少,因此,为了在更加真实的情况下研究腹主动脉的血流动力学参数,我们建立了一个具有解剖真实的理想化几何模型,并且通过数值模拟的方法来定量的描述脉动流的血流动力学.
作者:黄伟;刘有军;主海文;刁越;高松 刊期: 2003年第z1期
Introduction It is well known that the deformation of an adherent leukocyte plays a critical role in response to external mechanical forces, but it remains to be elucidated that if it's nucleus deforms with cell deformation. Studies using parallel flow chambers, radial flow assays show that the stiffness of leukocyte increases when cells are allowed to spread or after adaptation to flow,both conditions being associated with a remodeling of the cytoskeleton ( Dong and Lei, 2000). However, most of these models are based on the hypothesis that the leukocyte is a solid sphere.
作者:Xiaoheng LIU;Xiong WANG;Hua HUANG 刊期: 2003年第z1期
We studied the role of p53 gene in the biorheologiy and biology in murine erythroleukemia cell line ( MEL), with the goal of understanding the influence of this tumor suppressor gene on the deformability and metastasis of tumor cells,. Experiments were performed on MEL - M and MEL - W, which expressed a mutant p53 gene and over - expressed the wild - type p53 gene, respectively, as well as the MEL cells transfected with an empty plasmid.
作者:Zongyao WEN;Weijuan YAO;Li GU;Chien SHU 刊期: 2003年第z1期
Platelet-derived growth factor beta - receptors ( PDGF beta - R) undergo directed movements in living cells, a process mediating cell migration. Motile actin filaments possibly contribute to such movements. We investigate here the interaction of PDGF beta - R with actin filaments, and a possible role for focal adhesion kinase (FAK) , an actin - associated protein, in the regulation of such a process by magnetic manipulations of the PDGF beta - R and genetic modulations of the FAK gene in cultured mouse embryonic fibroblasts.
作者:Shu Q. LIU;Christopher TIECHE;Yan - chun LI;Paul K. ALKEMA 刊期: 2003年第z1期
前言在体动脉的内皮细胞暴露于血流中,同时承受着血流产生的壁切应力(WSS)和血压导致的周向应力(CS)的作用.在体或离体的研究表明,血流切应力和周向应力与内皮细胞的结构和功能密切相关.但绝大部分研究都是研究血流切应力或周向应力对内皮细胞的单独作用.由于在体动脉中血流和血压不是孤立存在的,它们之间存在着联系,因之产生的血流切应力和血管周向应力不是孤立地对内皮细胞起作用,而是联合地起作用.已有的在体实验结果表明,低流体切应力和高周向应力的联合作用与动脉粥样硬化紧密相关.
作者:覃开蓉;柳兆荣;Akira KAMIYA;Joji ANDO 刊期: 2003年第z1期
采用异种动物血管制作组织工程血管的支架,再种植宿主自体平滑肌细胞和内皮细胞,是目前较理想的构建组织工程血管的模型.然而,胶原纤维、弹力纤维、细胞外基质和脱细胞后残留的细胞碎片都具有抗原性,尤其是细胞膜上的MHC是一种强烈的移植抗原,如何处理生物支架的抗原性是构建全生物化组织工程血管的一个关键问题之一.同时,在支架种植细胞前检测其抗原性的强弱也是必须的基础技术之一.本文选择血管壁组织细胞高表达的MHC I作为检测指标,观察血管支架处理前后MHC I的变化情况.
作者:刘太华;张炎;李玉泉;刘波;张秀花;姜宗来 刊期: 2003年第z1期
心血管系统中,由于心脏有节律的收缩和舒张引起动脉管壁周期性运动,血管平滑肌细胞(Vascular Smooth Muscle Cells)受到脉动式交变张应力作用.长期以来,人们认识到张应力/应变对细胞的生长、增殖及重建起着重要的作用.本文利用自行研制的脉动膜式张应力施加装置,对成年雄性SD大鼠胸主动脉血管平滑肌细胞加载,研究弹性基底膜周期性应变对血管平滑肌细胞生长与增殖的影响,并初步探讨细胞骨架重建过程中的力学响应机制.
作者:何辉;樊瑜波;邹远文;宋锦璘;陈道运;蒋文涛;郭欣 刊期: 2003年第z1期
Introduction The silk fibers of silkworm have extraordinary mechanical properties. People commonly recognize that the ?- sheet structure in it mainly contributes that. So the formation of silk fiber from fibroin gel should be studied. Fibroin is primarily synthesized in the posterior division of silk gland of fifth - instar silkworm larva and from the posterior part to the anterior part of silk gland, the concentration of solution increases as well as a conformational transition, ? - helix to ? - sheet transition, occurs simultaneously. But little is known about the detailed process of the conformational transition under the influence of the concentration of fibroin gel. The present work studies the conformational transition of fibroin solution when it is diluted.
作者:Bo HUO;Xuan ZHU;Yong ZHAI 刊期: 2003年第z1期
越来越多的研究证据表明,血流动力学因素在动脉粥样硬化的发生和发展过程中起着关键的作用.但时至今日血流动力学因素确切的作用还需要进一步了解,因此,更深入地研究动脉粥样硬化的生物力学机理对于掌握动脉粥样硬化的病理和发病规律有着巨大的研究价值.
作者:王家权;于晓军;曾衍钧;伍时桂;徐小虎 刊期: 2003年第z1期
Limitations in the size and amount of bone tissue produced in vitro via tissue engineering are mainly due to the lack of nutrient and oxygen supply to the cells some distance away from the surface. Our laboratory has investigated possibilities for growing bulky bone tissue using novel hollow fibre bioreactors. The hollow fibre membranes embedded in the three dimensional scaffold are porous and semi permeable, which can serve the function of arteries and veins.
作者:Hua YE;Zhidao XIA;David J. P. FERGUSON;James T. TRIFFITT;Zhangfeng CUI 刊期: 2003年第z1期
自在20世纪70年代初,随着与生物医学工程、生物力学相关的法医鉴定的增多,法医学与生物医学工程、生物力学相互交叉逐渐形成了法医生物医学工程、法医生物力学等新的分支学科.
作者:许燕;樊瑜波 刊期: 2003年第z1期
植物的次生代谢是植物在长期进化中与环境(生物的和非生物的)相互作用的结果,次生代谢产物在植物提高自身保护和生存竞争能力、协调与环境关系上充当着重要的角色,其产生和变化比初生代谢产物与环境有着更强的相关性和对应性.因此,有必要从次生代谢角度去探讨植物与环境的关系.在各种不同的环境条件下,植物次生代谢的发生(环境诱导)和调控、次生代谢产物的产出效率以及次生代谢与初生代谢的平衡关系是近年来植物生理学家们极感兴趣的研究内容,从动态发展的角度看,植物与环境的关系就是植物对环境的适应与进化的过程.
作者:段传人;王伯初 刊期: 2003年第z1期