虹膜组织力学特性的实验研究

目的 模拟眼内前后房压强差，对人眼和兔眼虹膜整体加压，研究其力学特性。方法将瞳孔水密缝合，不破坏其几何形态，对虹膜整体加压。结果 首次实现了对虹膜整体力学特性的认识，人眼和兔眼虹膜力学特性相似，虹膜是典型的粘弹性物质，面积模量与前后房压强差之间基本呈线性关系，并且在相同的前后房压强差下人眼虹膜的面积模量比兔眼虹模的略小。结论 实验结果可为青光眼致盲机理解释和瞳孔阻滞力的估算提供参考；同时，经适当修正后，兔虹膜可作为人虹膜力学特性的研究样本，大大降低研究成本。     

兔眼虹膜组织力学特性的实验研究

利用我们创建的将兔眼蝉孔水密缝合后，模拟眼内前后房压强差，对虹膜整体进行加压的实验方法，对兔眼虹膜的力学特性进行了实验研究。结果表明：兔眼虹膜是典型的粘弹性物质；面积模量与前后方压强差之间基本成线性关系。实验结果可为青光眼致盲机制解释和瞳孔阻滞力的估算提供参考。     

虹膜组织力学特性研究的实验方法探索

创建了将眼瞳孔水密缝合后,在不破坏其正常功能作用的几何形态条件下,模拟眼内前后房压强差,对虹膜整体进行加压的实验方法。首次使眼虹膜整体力学特性的认识成为可能,本方法的实验结果将另文报道。     

猪眼虹膜力学特性的实验研究

研究猪眼虹膜的生物力学特性.通过模拟闭角型青光眼发生时眼睛前后房的力学环境,设计了一种实验方法并建立了闭角型青光眼的动物模型,在不破坏虹膜组织的完整性并尽量保持其活性的前提下,对猪眼虹珑膜的力学特性进行测试,得到了猪眼虹膜的面应变与前后房压强差之间的关系,可表示为δ=b0 b1ln△P,它具有黏弹性性质.实验结果还可为解释青光眼致盲机理和临床分析青光眼的病理状况提供理论和实验基础.     

膝关节制动对髌韧带力学特性影响的实验研究

探讨膝关节制动对髌韧带力学特性和影响。我们将兔膝关节伸直位制动６周。然后对制动前后髌韧带的本构方程、极限强度、弹性模量、极限载荷等力学性进行研究．结果显示：正常组与制动组间髌韧带的应力－应变关系理论曲线有明显不同,其材料常数亦有显著差异;制动组髌韧带的极限强度张弹性模校正常组均有明显下降,其极限载荷下降不明显。上述结果表明膝关节制动使得髌韧带所受应力下降,为适应这种改变,组织将进行重塑,从而导致其     

人体肺部组织介电特性实验研究

研究人体肺癌组织与正常组织介电特性差异,建立人体肺部组织介电参数频率谱图,为基础医学和临床诊断提供理论依据和数据参考.以肺癌手术中切下的患者癌变组织和癌周正常组织为样本,控制测试舱的温度和湿度,采用Agilent公司的4294A阻抗分析仪,在100 Hz～ 100 MHz频率范围内测量样本组织的介电特性.基于Cole-Cole模型利用最小二乘曲线拟合方法,提取两种组织的特征参数.在所测频率范围内,肺癌组织的相对介电常数为正常组织的3～5倍,电导率为正常组织的1.6～3.3倍,肺癌组织的介电谱明显地向低阻抗方向移动.在提取的特征参数R0、R∞、α、Υ和fc中,低频电阻R0的差异具有统计学意义(P＜0.05).人体肺癌组织与正常组织的相对介电常数、电导率及低频电阻R0存在明显差异,可为人体肺组织介电特性研究和EIT测量提供基础数据.     

兔子宫壁组织力学特性的实验研究

目的 研究兔子宫壁组织的生物力学特性,并对分娩与未分娩组兔子宫壁力学特性进行比较.方法 以14只新西兰雌性大白兔为研究对象,取其子宫壁组织为拉伸试样,分娩与未分娩分组对照,用WDW4100微机控制电子万能实验机进行拉伸实验,测定其极限强度、应力应变关系;蠕变实验和应力松弛实验测定其黏弹性特征.结果 兔子宫壁组织表现出明显的黏弹性特征,应力应变呈指数关系;分娩组的平均极限应力为0.119MPa,未分娩组的平均极限应力为0.444MPa;分娩组的蠕变和松弛实验均明显比未分娩组低.结论 分娩与未分娩的兔子宫壁组织生物力学特性有明显的差别,对临床上研究人类子宫壁组织有一定的参考价值,有助于妇产科学的发展.     

虹膜组织力学特性及瞳孔阻滞力定量研究的方法学探索

目的:寻找一种能对虹膜本构关系以及原发性闭角型青光眼瞳孔阻滞力进行定量研究的方法,为闭角型青光眼的早期诊断及治疗方法的选择和治疗效果的评价提供一种定量标准.方法:根据瞳孔阻滞产生机制,设计瞳孔阻滞力仿真方法;依据力学原理和自定义的虹膜面应变、面积模量等建立虹膜的本构关系.结果:设计了一种不破坏虹膜正常功能和形态学结构,对虹膜组织力学特性及瞳孔阻滞力进行定量研究的方法.     

血液粘弹特性的力学模型

本文提出一个由弹性模量为Ｇ的胡克弹簧和粘度为ηＣ（Ｃａｓｓｏｎ粘度）的阻尼器相串联的粘弹体力学模型，并讨论这一模型的粘弹特性：应力松驰、蠕变和动粘弹性。结果表明，这些特性与具有屈服应力的血液的粘弹行为相一致（除蠕变外）。由此现模型可视为血液粘弹特性一个简化的力学模型。本文还探讨了屈服应力与粘弹特性的相互关系。     

工程化组织动物体内植入的生物力学测试

工程化组织逐渐成为修复病损组织最具挑战性的新型替代材料。这种材料具有生命活性,植入体内后被降解吸收的同时,可再生组织,从而修复组织缺损,达到牢固的自体组织愈合并重建功能。在研究工程化组织植入体内愈合的过程中,检测植入的工程化组织的生物力学特性是考察其愈合和修复效果的重要方面。本文介绍了工程化组织植入动物体内生物力学检测的样本制备及保存、基本试验方法、近似试验方法和有关对实验结果的影响因素,为工程化组织的体内检测提供重要参考。     

兔眼角膜生物力学特性的实验研究

目的：了解兔眼角膜的力学特性，得出以面应变γ与角膜内外压强差p′表达的本构方程。方法：模拟眼内压．测量了20只免眼角膜。结果：获得了本构关系γ=γ0exp(c／p′)和面积模量E=A Bp′。结论：角膜是不易发生较大变形的粘弹性材料。     

门静脉高压症猪肺血管的生物力学特性

目的：探讨门静脉高压症猪肺血管的生物力学特性及为临床晚期肝硬化患者实施肝肺联合移植提供理论依据。方法：采用健康2月龄湖北白种猪4头作为正常对照组，四氯化碳诱导的门静脉高压组湖北白种猪10头，分别取其肺动脉、肺叶动脉、肺段动脉及肺静脉，在软组织生物力学试验机上测定压力一直径关系数据，推导出其弹性模量和顺应性。结果：与正常对照组相比，门静脉高压组（PHT）猪肺动静脉血管的弹性模量随血管内压力的升高而增大；顺应性则随血管内压力的增大而下降。结论：与人类相似，PHT猪可伴有肺血管生物力学特性的改变，且生物力学特性变化的幅度可能与病情变化有关。肝肺联合移植时，移植材料间的生物力学特性也应引起关注。     

Importance of a distal centralizer in experimental malpositioning of cemented stems. A biomechanical study on human femora

Introduction

Femoral centralizers in total hip arthroplasty (THA) are designed to improve the neutral implant position and ensure a homogeneous cement mantle without implant-bone impingement. To date there are no data about the cement mantle configuration and implant position after malinsertion, as seen in mini-open approaches or adipose patients with a limited view. The present biomechanical study was performed to investigate whether a distal centralizer may correct and optimize the position of a malinserted femoral stem.

Material and methods

Thirteen MS 30 stems with and without a distal centralizer each were implanted in paired fresh human femora. Malinsertion was performed using a 3D guiding device with 10° deviation to the femoral axis in the sagittal plane. The thickness of the cement mantle was measured on the anterior, posterior, medial and lateral side of the implanted stem at a distance of 1 cm each. For each side data were taken at 13 points.

Results

Digital evaluation of the cement mantle thickness revealed compareable values in frontal plane when a centralizer was used (p > 0.4). In contrast the cement mantle thicknesses without a centralizing device varied in the distal region between 3.38 mm and 5.09 mm (p ≤ 0.001) and in the central region between 3.52 mm and 4.19 mm (p ≤ 0.009).

Conclusions

A distal centralizer allows a more uniform cement mantle and neutral alignment even with a malinsertion of the femoral stem. This could reduce the failure rate and early loosening in complex THA.     

人类组织因子途径抑制因子的研究进展

人类组织因子途径抑制因子属于库尼(Kunitz)型丝氨酸蛋白酶抑制剂家族蛋白,分为组织因子途径抑制因子-1(tissuefactorpathwayinhibitor-1,TFPI-1)和组织因子途径抑制因子-2(tissuefactorpathwayinhibitor-2,TFPI-2)。TFPI-1以抗凝血作用为主,而TFPI-2是广谱丝氨酸蛋白酶抑制剂。二者在结构上有部分同源性,均由3个重复的Kunitz结构域组成。但二者在基因序列、组织来源、分布和作用机理上的很大差异,导致二者在多种生理和病理过程中发挥的作用也大不相同。就有关研究进展做一综述。     

Calretinin expression in human normal and neoplastic tissues: a tissue microarray analysis on 5233 tissue samples

Calretinin is a calcium-binding protein expressed in different normal and neoplastic tissues. Early studies suggested that calretinin is a useful marker to differentiate adenocarcinomas from malignant mesotheliomas of the lung, but subsequent work has shown that calretinin can be expressed in several other tumor types. To systematically investigate the epidemiology of calretinin expression in normal and neoplastic tissues, we used tissue microarrays (TMAs) to analyze the immunohistochemically detectable expression of calretinin in 5233 tissue samples from 128 different tumor categories and 76 different normal tissue types. At least 1 case with weak expression could be found in 74 of 128 (58%) different tumor types and 46 entities (36%) had at least 1 tumor with strong positivity. In normal tissues, a particularly strong expression was found in Leydig cells of the testis, neurons of the brain, theca-lutein and theca interna cells of the ovary, and mesothelium. In tumors, strong calretinin expression was most frequently found in malignant mesotheliomas (6 of 7), Leydig cell tumors of the testis (5 of 5), adenomas of adrenal gland (5 of 9), and adenomatoid tumors (4 of 9). In summary, calretinin is frequently expressed in many different tumor types. Metastases of various different origins must be included in the differential diagnosis of calretinin-positive pleura tumors.     

Micro-CT-based screening of biomechanical and structural properties of bone tissue engineering scaffolds

The development of successful scaffolds for bone tissue engineering requires a concurrent engineering approach that combines different research fields. In order to limit in vivo experiments and reduce trial and error research, a scaffold screening technique has been developed. In this protocol seven structural and three biomechanical properties of potential scaffold materials are quantified and compared to the desired values. The property assessment is done on computer models of the scaffolds, and these models are based on micro-CT images. As a proof of principle, three porous scaffolds were evaluated with this protocol: stainless steel, hydroxyapatite, and titanium. These examples demonstrate that the modelling technique is able to quantify important scaffold properties. Thus, a powerful technique for automated screening of bone tissue engineering scaffolds has been developed that in a later stage may be used to tailor the scaffold properties to specific requirements.