介绍一种获取胎儿细胞的方法

对于那些有遗传病家族史或生育过患儿的孕妇来说，如何能在孕早期确诊胎儿是否异常有十分重要的意义。目前孕早期产前诊断急待解决的问题是取样技术的突破。我们采用套管拭子法在早孕妇子宫腔下部采集脱落细胞，进一步确定胎儿细胞在女性生殖道的存在。     

基于统计独立性度量方法的大肠杆菌基因调控网络结构辨识

生物学探究的基因关联是类似于因果关系的本质联系,要解决的关键问题是寻找一种可以描述本质联系的方法.针对Dialogue for Reverse Engineering Assessments and Methods第3次竞赛项目(DREAM3)中的大肠杆菌(E.coli)基因调控网络结构辨识问题,提出一种基于再生核希尔伯特空间(RKHS)的统计独立性度量方法——Hilbert-Schmidt独立性准则(HSIC).此方法是一种基于分布的非参数独立性度量方法,并不要求数据符合某种特定分布,不以分类率、模型简单度等外部条件作为约束条件,同时非参数定量地描述变量之间的联系程度.对大肠杆菌基因表达数据的实验结果显示,尽管数据集中的时间序列数据样本很小,并且只提供了较弱的和类型复杂的调控信息,但HSIC方法仍能较好地辨识出这种较为隐含且复杂的调控关系.对比计算显示,在3种数据规模下,采用HSIC方法辨识结果的AUROC值高于Granger Causality(GC)方法23个百分点,高于参与此竞赛的第1名3.9个百分点,而且在计算效率上亦高出其所使用的微分方程法3个数量级.     

细胞形态与功能的一种工程化控制方法

将一种含有定义在微米量级水下上的特征图形的橡胶模压印在全表面特殊类型的烷硫醇自组装单分子层上，从而形成许多具有确定形状与尺寸的岛，这些岛可以供作胞外基质吸附与细胞贴附的“抛锚地”。通过这项技术，有可能将目标细胞放置到一个预定的位置上并它们排成相隔距离一定的阵列，从而有可能规约它们的形状，对细胞延展程度的限制给人们提供了控制细胞生长与蛋白质分泌的一种机会。这种方法在个是很简单的并且有很灵活的可适应性     

一种改良的羊水细胞染色体制备方法

目的 为了探索一种快速,简便,稳定的羊水细胞染色体制备方法,提高产前诊断成功率。方法 对50例15.3-29.5孕周有产前诊断指征的孕妇,抽取羊水,经细胞原位培养,加入秋水仙素3-4h后,摇动培养瓶,收获羊水细胞。结果50例羊水细胞培养成功率为100％,细胞染色体形态质量好。结论 本方法具有简便、快速、染色体带型稳定等优点,有实用价值。     

两种体外细胞毒性检测方法的比较研究

目的比较两种常用的细胞毒性检测方法在医疗器械生物学评价中的相关性.方法分别采用MTT比色法和细胞增殖度法,在37℃条件下,将五种医疗器械/生物材料的浸提液分别与小鼠成纤维细胞(L-929)接触2天和2,4,7天,比较材料对细胞的毒性影响.结果 5种不同的材料浸提液分别表现出不同程度的细胞毒性反应(0～2级).将MTT比色法与细胞增殖度法(2天)的实验数据进行相关性分析,显示两者之间具有良好的相关性(R=0.977).结论 MTT比色法由于其检测所需的细胞量相对较少,试验步骤相对简便、检测周期短,因此具有一定的优越性,是个值得推荐的细胞毒性检测方法.     

一种新的人活化T细胞抗原p140的分布及其功能的研究

目的 观察一种新的活化T细胞膜分子p140的分布、相对分子质量（Mr)和功能。方法 用免疫芝光染色和流式细胞术观察p140分子的分布;采用重导向杀伤实验观察其对杀伤功能的调节;应用生物素标记细胞膜分子、免疫沉淀及化学发光测定p140的Mr。结果 p140分子可选择性地表达于混合淋巴细胞培养（MLC）所产生的活化T细胞表面,而在抗CD3 mAb、PHA、PMA或PMA＋A23187几种刺激剂活化的人外周血单个核细胞（PBMC）上未见表达。p140还分布于一些人急性T细胞性白血病细胞系。在重导向杀伤实验中,p140与CD3分子有协同作用。p140M,为140000。结论 p140可能为一种新的移植抗原诱导的T细胞活化分子,同CD3分子具有协同刺激作用。     

介绍一种定量检测细胞凋亡的方法

Ｆｏｒｓｋｏｌｉｎ（毛喉萜）为二萜类有机化合物。已证实它能直接激活腺苷酸环化酶。使胞内ｃＡＭＰ浓度升高,导致胞内ＤＮＡ断裂,细胞呈现凋亡［１］。本文采用Ｆｏｒｓｋｏｌｉｎ介导小鼠胸腺细胞凋亡,并采用新的一种定量检测细胞凋亡的方法,呈现与流式细胞术（Ｆ...     

一种与N-Back诱发脑力疲劳相关的特异性脑电网络结构

探究脑力疲劳引起的静息态脑电网络结构的改变,以及体力疲劳的引入对脑力疲劳相关脑电网络的影响。分别以2-back实验和功率自行车诱发脑力、体力疲劳,采集10名被试脑力疲劳前后以及体脑疲劳前后4种状态下20个导联的静息脑电信号(EEG),进行偏定向相干因果性分析。对被试的脑电网络连接逐个进行威尔科克森符号秩检验,选择PDC值显著性大于阈值的连接赋为1,构建出二值化脑电网络。通过对疲劳前后脑电网络的比较与拆分计算,提取出一个N-back实验下与脑力疲劳相关的特异性脑电网络结构,该网络以额区的FP2导联为中枢节点,呈现出由全脑所有导联指向FP2的规律。在脑力疲劳和体脑疲劳两种疲劳状态下,该网络的连接形式基本保持一致,连接系数分别是4.060 3和4.142 1,没有发生显著改变,所以是一种相对独立、稳定并与脑力疲劳密切相关的功能网络。该方法和结果有望为研究脑力疲劳和探索体脑疲劳交互影响机制提供一个新的视角。     

一种改进的大鼠大脑皮质星形胶质细胞的培养方法

目的:改进大鼠大脑皮质星形胶质细胞的培养方法,从而获取高纯度星形胶质细胞用于神经科学研究。方法:新生大鼠(2~3日龄),75%酒精消毒后断头,于冰上取大脑皮质置于冰冷的D-Hanks液中,去除脑膜和血管,剪碎后用0.25%胰酶消化并分离细胞,以1×10~5/ml的密度接种于预铺0.015%多聚赖氨酸的细胞瓶中培养。细胞纯化采用"差速贴壁法"、"梯度血清法"和"十字手摇法",以获取高纯度星形胶质细胞。通过星形胶质细胞特异性表达蛋白即胶质原纤维酸性蛋白(GFAP)行免疫细胞荧光染色来鉴定细胞纯度。结果:星形胶质细胞纯度大于98%,可多次传代,细胞增殖快,且生长良好。结论:改进的原代星形胶质细胞培养方法,操作简单,细胞纯度高,能满足各种神经科学研究中对高纯度星形胶质细胞培养的实验要求,适宜推广。     

基于氨基酸疏水性与PSSM构建ANN预测蛋白质二级结构

目的 预测蛋白质二级结构是预测其空间结构的基础,提高蛋白质二级结构的预测率非常重要.方法在本研究中,结合氨基酸的疏水性与含有进化信息的位置特异性得分矩阵(PSSM),构建BP神经网络.本文的数据来源于蛋白质数据集合CB513,在此集合中去除氨基酸个数小于30及含有X、B的序列,共492条蛋白序列作为数据集.通过4-交互验证预测准确率.在本研究中,将蛋白质二级结构预测的结果与仅用PSSM作为输入的神经网络预测相比较.结果 采用疏水性与进化信息相结合作为输入所构建的神经网络对α螺旋的预测准确率有了较大的提高,达到近79%,敏感性及特异性分别达到79%及91%.同时对二级结构总体预测准确率达到75.96%.结论 此种方法构建的BP网络能提高蛋白质二级结构,尤其是α螺旋的预测准确率.     

A fuzzy clustering neural network architecture for classification of ECG arrhythmias

Accurate and computationally efficient means of classifying electrocardiography (ECG) arrhythmias has been the subject of considerable research effort in recent years. This study presents a comparative study of the classification accuracy of ECG signals using a well-known neural network architecture named multi-layered perceptron (MLP) with backpropagation training algorithm, and a new fuzzy clustering NN architecture (FCNN) for early diagnosis. The ECG signals are taken from MIT-BIH ECG database, which are used to classify 10 different arrhythmias for training. These are normal sinus rhythm, sinus bradycardia, ventricular tachycardia, sinus arrhythmia, atrial premature contraction, paced beat, right bundle branch block, left bundle branch block, atrial fibrillation and atrial flutter. For testing, the proposed structures were trained by backpropagation algorithm. Both of them tested using experimental ECG records of 92 patients (40 male and 52 female, average age is 39.75 +/- 19.06). The test results suggest that a new proposed FCNN architecture can generalize better than ordinary MLP architecture and also learn better and faster. The advantage of proposed structure is a result of decreasing the number of segments by grouping similar segments in training data with fuzzy c-means clustering.     

A sub-space greedy search method for efficient Bayesian Network inference

Bayesian network (BN) has been successfully used to infer the regulatory relationships of genes from microarray dataset. However, one major limitation of BN approach is the computational cost because the calculation time grows more than exponentially with the dimension of the dataset. In this paper, we propose a sub-space greedy search method for efficient Bayesian Network inference. Particularly, this method limits the greedy search space by only selecting gene pairs with higher partial correlation coefficients. Using both synthetic and real data, we demonstrate that the proposed method achieved comparable results with standard greedy search method yet saved ∼50% of the computational time. We believe that sub-space search method can be widely used for efficient BN inference in systems biology.     

A method for determination of antibody-dependent cellular cytotoxicity (ADCC) of human peripheral mononuclear cells

A method is described for measuring antibody-dependent cellular cytotoxicity (ADCC) of mononuclear cells from human peripheral blood using an established murine cell line and commercially prepared antisera. The test utilizes a standard 51Cr release technique. The ADCC activity of mononuclear cells obtained from 10 healthy human volunteers was measured at 4 different effector: target cell ratios. A linear relationship between %51Cr release (ADCC) and the number of effector cells was observed.     

STON: A novel method for protein three-dimensional structure comparison

Protein structure comparison is an important problem in bioinformatics and has many applications in the study of structural and functional genomics. During the last decades, various heuristic methods have been developed to solve the protein structure comparison problem. Most of the protein structure comparison methods give the alignment based on the minimum RMSD (root mean square deviation) and ignore many significant local alignments that may be important for evolutional or functional studies. We have developed a new algorithm to find aligned residues in two proteins with desired RMSD value. The parameterized distance and rotation in this program enable us to search for strongly or weakly similar aligned fragments in two proteins.     

A novel reticular stromal structure in lymph node cortex: an immuno-platform for interactions among dendritic cells, T cells and B cells

For efficient adaptive immunity, the lymph nodes (LNs) are equipped with a strategically organized microarchitecture, which is largely supported by the reticular network (RN). The RN can be clearly visualized by fluorescence immunohistochemistry coupled with confocal imaging using a monoclonal antibody, ER-TR7, and can be subdivided into four structurally distinct regions, each of which correlates well with the location of distinct immune cell subsets. In addition, we noticed a characteristic reticular structure designated the 'cortical ridge' at the boundary of the T and B zone, in which dendritic cells are preferentially accumulated. In vitro adhesion assays of frozen sections demonstrated a preference of dendritic cells for the cortical ridge rather than the deeper cortex. Adoptive transfer experiments also demonstrated that antigen-bearing dendritic cells migrated to this region from peripheral tissues, especially in the vicinity of the high endothelial venules, and were anchored on the reticular fibers waiting to interact with the antigen-specific T cells. Taken together, the findings obtained in this study provide new insights into how the LN stromal reticulum works as a specialized 'immuno-platform' for tissue compartmentalization and the immune response.     

A human pericardium biopolymeric scaffold for autologous heart valve tissue engineering: cellular and extracellular matrix structure and biomechanical properties in comparison with a normal aortic heart valve

The objective of our study was to compare the cellular and extracellular matrix (ECM) structure and the biomechanical properties of human pericardium (HP) with the normal human aortic heart valve (NAV). HP tissues (from 12 patients) and NAV samples (from 5 patients) were harvested during heart surgery. The main cells in HP were pericardial interstitial cells, which are fibroblast-like cells of mesenchymal origin similar to the valvular interstitial cells in NAV tissue. The ECM of HP had a statistically significantly (p < 0.001) higher collagen I content, a lower collagen III and elastin content, and a similar glycosaminoglycans (GAGs) content, in comparison with the NAV, as measured by ECM integrated density. However, the relative thickness of the main load-bearing structures of the two tissues, the dense part of fibrous HP (49 ± 2%) and the lamina fibrosa of NAV (47 ± 4%), was similar. In both tissues, the secant elastic modulus (Es) was significantly lower in the transversal direction (p < 0.05) than in the longitudinal direction. This proved that both tissues were anisotropic. No statistically significant differences in UTS (ultimate tensile strength) values and in calculated bending stiffness values in the longitudinal or transversal direction were found between HP and NAV. Our study confirms that HP has an advantageous ECM biopolymeric structure and has the biomechanical properties required for a tissue from which an autologous heart valve replacement may be constructed.     

A method for quantitative determination of average masses and concentrations of circulating immune complexes in human sera

A method for rapid determination of average masses and concentrations of circulating immune complexes in human sera is suggested. It is based on the dissimilarity in solubilities of immune complexes with different masses in the presence of polyethyleneglycol. Light-scattering intensities are measured by a laser nephelometer after adding to the serum of PEG in two different concentrations. The experimental values of the average masses and concentrations are calculated using calibration curves. The calibration curves are plotted for model immune complexes with different average masses obtained by heat-aggregation of IgG at various concentrations. This technique has been employed for determination of the average masses and concentrations of circulating immune complexes in 17 patients suffering from systemic lupus erythematosus and in 8 control individuals.