一种体外贴壁细胞应变加载装置的研制

目的开发一套新型的应变加载装置,用于贴壁细胞力学生物学研究。方法该装置基于基底形变加载技术,采用可控制编程器驱动步进器,引起硅橡胶小室变形,实现多单元大应变的细胞加载;研制该装置,检测机械性能;建立硅橡胶小室的三维模型,利用有限元技术对硅橡胶小室进行仿真,分析该小室的应变场均匀性问题;采用该装置对骨髓间充质干细胞(bone marrow stromal cells,BMSCs)加载5%机械应变,频率0.5 Hz,2 h/d,持续5 d,并在倒置显微镜下观察细胞形态的变化。结果所研制的适用于体外细胞加载装置可对3组细胞加载基底实现最大至50%机械单向应变;在10%应变范围内,硅橡胶小室底部的均匀应变场面积占比保持在50%以上,保证了细胞受力均匀; BMSCs形态发生明显变化,排列方向趋于垂直主应变加载方向。结论该装置运行可靠,应变范围宽,频率可调,操作方便,可同时对多组细胞培养基底进行应变加载,为细胞力学生物学研究提供了便利条件。     

一种血管张应力体外加载装置的实验研究

目的研制一种血管张应力体外加载装置,研究弹性基底(硅胶片)上的张应力、张应变分布。方法基于基底形变加载技术,研制一种接近人体血液动力学环境的血管张应力体外加载装置。利用装置中的摄像机拍摄硅胶片拉伸前后硅胶片网格点的图像并转化为数字图像,使用Matlab软件对网格点的位置特征进行计算,从而得到硅胶片的应变分布。利用万能材料试验机对硅胶片进行实验和计算得到硅胶片的力学参数,根据力学参数建立有限元模型,并对硅胶片的张应力、张应变分布进行模拟计算。将实验结果和模拟结果进行比较。结果有限元结果和实验结果基本一致,张应力、张应变的最大值均出现在加载点处,中间区域应力、应变较为均匀。硅胶片中间60%面积区域可视为均匀应变场。结论研究结果可为后期血管壁内皮细胞的动态培养以及细胞力学研究提供实验技术。     

一种改进型动态应变三维细胞培养装置的研制

介绍了一种用于组织工程研究的改进型动态应变细胞培养装置,针对原有的旧设备,分别从控制单元的硬件和软件设计、机械单元结构及细胞培养单元的结构三方面进行改进和升级,新装置使用范围广、可控精度高、操作简单。     

多通道细胞牵张应变加载系统的建立及应用

本研究自行开发了单片机控制的多通道细胞牵张应力加载仪,控制与真空室相连的真空泵,使真空室内的负压产生周期性变化,使置于真空室上的弹性膜培养板底壁的弹性膜发生变形,对培养于弹性膜上的细胞施加牵张应变,实现对细胞施加周期性拉伸变形的作用。控制系统可以同时进行三通道不同形变率的对比实验,而且体积小,便于携带,形变率、频率可以精确调节,操作简单,可以提供1%～21%范围的形变率,应变频率可在0～0.5Hz范围内可调。系统运行稳定,达到了设计要求,提供了对贴壁生长细胞施加基底膜牵张应力的体外实验方法。     

血管张应力体外加载装置的研制

背景：国内外已经研制出多种体外细胞张应力加载装置,主要拉伸方法有矩形基底拉伸法、圆形基底变形法和4点弯曲梁加载法3种,其中圆形基底变形法虽能够很好的反映体内如肺泡的扩张、血管的脉动等真实情况,但该种加载过程中膜的应变是辐射对称的;4点弯曲梁加载法能够提供的应变范围很小,加载时间有限,应变调节比较困难。 目的：采用矩形基底拉伸法研制血管张应力体外加载装置。 方法：采用机电一体化设计研制血管张应力体外加载装置,由电源模块、控制模块、传动模块和数据采集模块4个部分组成,以硅胶片为基底材料,通过对电机旋转角度和转动速度的高精度控制,实现对硅胶膜片上的拉伸控制。 结果与结论：通过测试和试验,该装置可以满足试验所需的参数范围,能够在体外模拟出人体张应力环境,初步认为该张应力加载装置的研制是成功的,实现了：①装置有两种工作模式：应力模式和应变模式,解决了基底加载装置的硅胶片材还没有实现标准化的问题。②能实现张应力在0-5×105 Pa范围内的调节。③能实现张应变在0-40%范围内的调节。④能实现0-80次/min的拉伸频率的变化,并能控制拉伸时间。中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

一种用于骨组织工程研究的加载装置

力学环境对骨内细胞的生物学行为有重要影响。无论是体内还是体外培养,骨组织的生长、发育都依赖力学环境。根据骨组织生理调节中的力学感知、传导、传质机理,研制一种用于骨组织工程研究的加载装置。该装置可为体外骨组织培养提供生理范围内不同大小、频率的应变及不同的应变波形,特别是对有一定强度的硬支架(与松质骨、密质骨强度相当)也能满足生理应变的要求。采用弹性较优的合成塑料作为参考支架进行有效性检测,结果表明在支架材料上此装置产生正常的生理应变,且重复精度高。装置使用智能材料-压电陶瓷作为动力来源,通过计算机控制实现了骨支架材料骨生理水平应变的精确控制。此装置将为工程化骨组织构建中载荷影响的研究提供方便。     

拉伸基底加载成骨类细胞内应变张量分析

根据黏附在基底材料膜上成骨类细胞的形态学特征，从细胞固体模型和细胞液滴模型讨论了细胞应变张量的均匀性，导出了反映单、双轴拉伸加载下细胞的应变特征张量。引入标量场参数λ描述细胞应变的非均匀性，给出了非均匀范围与细胞黏附形态几何参数的定量关系。结果有一定的理论和实验意义。     

可对细胞施加双向应变的体外培养系统

为考察体外培养细胞在动应变作用下的响应，参考Winston等人的方法，我们制作了一套细胞体外培养系统，培养皿用有机玻璃作成，培养皿底为硅橡胶膜，下面有一封闭压力腔，通过对硅橡胶管和挤压轮间隙的调整，压力腔内的液压使硅橡胶膜产生设计应变，其应变范围可从0～4％调整，改变步进电机的转动方式，加载频率可从0．1～5Hz变化。     

具有较大均匀应变区域贴壁细胞力学加载培养室的研制

目前研究力学因素对细胞行为的影响很大程度上依赖于离体实验,基于此本文研制了一种具有较大均匀应变区域的培养室,其中含有以直线电机为动力,频率高达20 Hz的细胞拉伸加载装置,可对细胞施加力学作用。本文以应变均匀为目标,基底厚度为变量,利用有限元技术对传统培养室的基板底部进行优化,最后构建了切面为“M”型结构的新型培养室三维模型,并采用三维数字图像相关法(3D-DIC)检测应变场和位移场的分布,以验证数值模拟结果。实验结果表明,新型细胞培养室增大了应变加载的准确性和均匀区域,较优化前提高了49.13%~52.45%。另外,利用该新型培养室初步研究了在同一应变、不同加载时间下舌鳞癌细胞的形态变化。综上,本文构建的新型细胞培养室结合了以往技术的优点,可传递均匀精准的应变,以便用于广泛的细胞机械生物学研究。     

周期性拉伸应力与人永生化角质形成细胞的黏附和铺展

背景：皮肤组织所处的力学环境以及上皮细胞的铺展状态与伤口愈合和瘢痕形成过程关系密切。 目的：分析胞外力学刺激对细胞铺展的作用,并检测细胞的增殖状态进一步分析铺展形态对细胞增殖等生理活动的影响。 方法：通过FX-4000柔性基底加载系统对人永生化角质形成细胞(HaCaT)进行周期性拉伸应力正弦波加载,加载程式0.2 Hz,10%拉伸幅度。在0,24,48 h对细胞的铺展形态进行对比,利用流式细胞仪检测分析细胞的增殖,并利用免疫荧光染色方法对比分析纽蛋白在细胞内的分布。 结果与结论：HaCaT细胞在加载24 h后分裂期细胞较多,铺展形态无明显变化;加载48 h后HaCaT细胞形态发生较为明显的变化,分裂期细胞较静态对照组略有减少;拉伸应力作用下纽蛋白的分布由细胞核周围的膜区域向细胞边缘集中。结果表明：适度的力学加载能够在保持细胞铺展和黏附状态下,促进细胞增殖;周期性持续拉伸应力的作用时间是HaCaT细胞铺展形态和与基底黏附位点的重要影响因素。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

应用静态进展性牵伸方法治疗膝关节挛缩

目的报道应用等速测力仪静态进展性牵伸治疗膝关节挛缩的方法及疗效。方法选取因骨折术后造成膝关节挛缩的患者16例,其中股骨干骨折2例,股骨远端骨折5例,髌骨骨折4例,胫骨平台骨折5例。术后平均病程13.7周。在等速测力计上实施静态进展性牵伸。每次关节活动在一个方向上牵伸,每次分5组牵伸,每组治疗时间5 min,组间休息1 min,下一组关节角度渐增。患者每日接受SPS治疗2次,每次治疗时间30 min,每周5 d,治疗疗程2月。分别在治疗前、治疗后、治疗后6月使用角度计测量伸膝角度E、屈膝角度F和关节活动度R。结果治疗后以及治疗后6个月,膝关节E、F、R 3个指标较治疗前均有明显改善(P<0.05)。结论应用等速测力仪静态进展性牵伸可以治疗膝关节挛缩。     

利用步态分析研究楔形鞋垫对膝关节载荷的影响

目的研究足底不同位置的楔形鞋垫对膝关节承载及运动特征的影响。方法利用三维动捕捉系统与测力台对10名健康成年女性受试者步态中的关节动力学变化特点进行分析研究。实验状态分为对照组和6组楔形鞋垫测试组。利用单因素方差分析评价楔形足底支撑对膝关节动力学参数的影响。结果相对于对照组,前内侧楔形鞋垫组显著减小了膝内翻力矩第1峰值(P<0.05);使用前外侧楔形鞋垫和外侧全长楔形鞋垫的两组显著减小了膝内翻力矩第2峰值(P<0.05,P<0.05)。结论使用楔形鞋垫可有效地减小站立相的膝关节内翻力矩,这将有助于设计适合的鞋垫以减轻由骨性关节炎所带来的疼痛。     

Release of cardiac troponin I from viable cardiomyocytes is mediated by integrin stimulation

Elevated cardiac troponin-I (cTnI) levels have been demonstrated in serum of patients without acute coronary syndromes, potentially via a stretch-related process. We hypothesize that this cTnI release from viable cardiomyocytes is mediated by stimulation of stretch-responsive integrins. Cultured cardiomyocytes were treated with (1) Gly–Arg–Gly–Asp–Ser (GRGDS, n = 22) to stimulate integrins, (2) Ser–Asp–Gly–Arg–Gly (SDGRG, n = 8) that does not stimulate integrins, or (3) phosphate-buffered saline (control, n = 38). Cells and media were analyzed for intact cTnI, cTnI degradation products, and matrix metalloproteinase (MMP)-2. Cell viability was examined by assay of lactate dehydrogenase (LDH) activity and by nuclear staining with propidium iodide. GRGDS-induced integrin stimulation caused increased release of intact cTnI (9.6 ± 3.0%) as compared to SDGRG-treated cardiomyocytes (4.5 ± 0.8%, p < 0.001) and control (3.0 ± 3.4%, p < 0.001). LDH release from GRGDS-treated cardiomyocytes (15.9 ± 3.8%) equalled that from controls (15.2 ± 2.3%, p = n.s.), indicating that the GRGDS-induced release of cTnI is not due to cell necrosis. This result was confirmed by nuclear staining with propidium iodide. Integrin stimulation increased the intracellular and extracellular MMP2 activity as compared to controls (both p < 0.05). However, despite the ability of active MMP2 to degrade cTnI in vitro, integrin stimulation in cardiomyocytes was not associated with cTnI degradation. The present study demonstrates that intact cTnI can be released from viable cardiomyocytes by stimulation of stretch-responsive integrins.     

体外心肌细胞牵张刺激装置的建立

目的：设计一套实用的体外培养心肌细胞牵张刺激模拟装置，为探讨心肌细胞机械刺激转导机制提供研究方法。方法：应用自行设计制作的离心力牵张装置模型和传统膜牵张模型刺激培养的乳鼠心肌细胞，通过细胞体积、数量，培养液中血管紧张素Ⅱ（Ang Ⅱ）水平和乳酸脱氢酶活性和同位素标记亮氨酸掺入法评价心肌细胞受损和肥大情况。结果：离心力牵张装置提供180 r/min的离心力和传统的20%的膜牵张力均可使培养心肌细胞体积明显增大，但对培养的心肌细胞的数量无显著影响。牵张刺激对培养液中乳酸脱氢酶活性影响无显著差异。[³H]-亮氨酸掺入在离心力牵张组（12 h为1295.17±51.19，24 h为1447.50±35.96，P<0.05）和膜牵张组（12 h为2015.50±79.06，24 h为1870.00±45.91，P<0.01）均显著高于对照组（12 h为1122.67±51.63，24 h为1210.67±90.92）。Ang Ⅱ在离心力牵张组[ 12 h为(22.6±3.2) ng·g^-1，24 h为(52.7±3.4) ng·g^-1 ]和膜牵张组[ 12 h为(28.3±6.3) ng·g^-1，24 h为(65.1±6.4) ng·g^-1 ]均明显高于同期未牵张组[ 12 h为(17.7±1.9) ng·g^-1，24 h为(37.8±2.3) ng·g^-1 ]。结论：离心力牵张装置可刺激培养心肌细胞发生肥大反应，与传统装置比较对其形态和代谢的影响小，应用更广泛和方便。     

Identification of Static and Dynamic Components of Reflex Sensitivity in Spastic Elbow Flexors Using a Muscle Activation Model

Static and dynamic components of the stretch reflex were studied in elbow flexors of 13 hemiparetic brain-injured individuals. Constant-velocity joint rotations were applied to the elbow, and the resulting stretch reflex torque and electromyographic responses were recorded in the biceps brachii and brachioradialis muscles. Ten elbow extension velocities between 6 and 150 ° s^-1 were applied in random order. The resulting reflex torque response was plotted as a function of elbow angle and fitted with a mathematical model designed to depict elbow flexor activation. We found that four of the six model parameters were essentially independent of test velocity. Conversely, 73% (19/26) of cases involving the other two model parameters were dependent on velocity of joint extension (p<0.05). We conclude from these results that four of the model parameters reflect the static reflex response while the two remaining velocity-dependent parameters reflect the dynamic reflex response. To describe overall velocity dependence of stretch reflexes in spastic elbow muscles, the two dynamic reflex parameters were fitted to a fractional exponential function of velocity, similar to a model previously used to describe spindle firing rate in the cat hindlimb. We found that the mean velocity exponent of the dynamic reflex parameters was 0.24 + 0.17 (s.d.) (N = 13), a value similar to that for muscle spindle velocity sensitivity in reduced animal preparations. We conclude that both static and dynamic reflex sensitivities can be measured by examining different aspects of the torque/angle relation associated with the reflex response to a large-amplitude ramp stretch of the elbow. © 2001 Biomedical Engineering Society. PAC01: 8719St, 8719Ff, 8710+e     

A versatile stretch sensor for measuring physiological movement using a centre loaded,end-supported load cell

Acquisition of movement of some body parts can provide important physiological information. In clinical practice as well as for research purposes different types of sensors such as piezoelectric crystals, conductive rubber and optical displacement sensors are used for such measurements. Each of these sensors is associated with its problems. This paper discusses the use of a stretch sensor constructed using a small metal bar, approximately the size of a zipper slider that can be sewn into a fabric in the form of a belt. A combination of elastic, and Velcro material attached to the metal bar, provides a sensor that is capable of linear, steady state measurement as well as rapid response detecting slow and fast movement of the target. Incorporating the sensor in an elastic belt, allows measurement of physiological movements such as respiratory chest movements, abdominal and limb movements. This paper also discusses the potential use of the novel stretch sensor in measuring change in calf circumference during different manoeuvres, making it a useful assessment tool for calf venous function.     

脊柱三维运动测试实验装置的研制

目的研制一套模拟人体脊柱在体运动的离体加载装置,进行脊柱生物力学实验研究。方法利用轴承原理,在加载盘上设计安装旋转锁定装置,加载时旋转于所需测试位置后用螺栓锁定状态,再通过万能材料试验机提供自动加载动力源,在脊柱标本上施加前屈/后伸、左/右侧弯和左/右轴向旋转6个方向的纯力矩,模拟脊柱的在体运动,并用三维扫描仪对脊柱标本加载前后位置进行扫描测量。利用该加载装置对6具1岁龄猪颈椎(C2-C6)在6种加载状态下进行运动范围测量,并对该加载装置进行精度验证和误差分析。结果建立了一套人体脊柱三维运动实验装置,6具猪颈椎标本经加载测量得到6个方向的中性区和活动范围数据,总测量误差值小于3.5%。结论该装置巧妙的设计较好地模拟了脊柱在体运动,可实现人体脊柱的快速加载,费用低、方法简单实用,能大大提高实验的效率,在脊柱的离体加载方面具有较大的推广应用价值。     

Development of insect cell lines: Virus susceptibility and applicability to prawn cell culture

Insect cells have been successfully cultured in vitro as continuous cell lines for over 35 years. The media, culture methodology and conditions have been well resolved such that, for many insects, new cells lines can be routinely developed. Factors that are considered important for developing insect cell cultures are described as well as some of the history that led to the success. One of the major rationales for developing insect cell lines was for the study of insect viruses. This was particularly true for species of Lepidoptera from which over 900 viruses have been reported. Since many species of Lepidoptera are serious agricultural and forestry pests, effects have been made to utilize some of these pathogens as biological pesticides. Cell cultures are important in this endeavor since viruses require a living cell to reproduce. Of the known insect viruses, the most intensely studied have been the baculoviruses. In addition to their potential for controlling insect pests, they also have been used as expression vectors for producing recombinant proteins. Details of some of these experiments are described. Finally, experiences with insect cells are considered in relation to efforts to develop prawn cell cultures.