微机矩阵算法程序在屈光学计算中的应用

本文介绍了一种应用微机BASIC语言的屈光学矩阵算法程序,可方便、迅速地解决许多眼科屈光学计算问题,如共轴球面折射系统、共轴球面反射、折射系统、球、柱镜偏心棱镜效应计算和散光柱镜系统的斜交球、柱镜组合计算等等。     

牛去细胞骨基质的生物相容性研究

目的 研究新型骨修复材料牛去细胞基质骨的生物相容性,为其在骨缺损修复领域中的临床应用提供实验依据.方法 对牛去细胞骨基质进行急性毒性实验、热源实验、溶血实验、兔肌肉内种植实验和兔桡骨骨缺损修复实验研究.结果 牛去细胞骨基质无毒性、无热源性、不引起溶血反应,植入兔肌肉后逐渐发生生物降解并被纤维组织取代,兔骨缺损区植入后可被骨组织取代.结论 牛去细胞骨基质具有良好的生物相容性,是理想的骨支架材料.     

脱钙骨基质与左旋聚乳酸/聚磷酸钙纤维对骨髓间充质干细胞黏附作用的比较

目的探讨左旋聚乳酸／聚磷酸钙纤维（PLLA／CPPf）与同种异体的脱钙骨基质（DBM）对BMSCs黏附作用的差异，为构建组织工程骨提供理想的支架材料。方法用扫描电镜观察两种支架材料的孔径；通过测吸水率比较其亲水性。将普通培养瓶培养的第3代BMSCs分别成骨诱导培养1周后，在体外分别与PLLA／CPPf和同种异体的DBM复合构建组织工程骨，于构建后10h计算细胞黏附率，并用扫描电镜观察比较两种支架材料对BMSCs黏附作用的差异。构建后每天在相差显微镜下观察BMSCs在两种支架材料上的生长情况，构建后第10天再行扫描电镜观察BMSCs在两种支架材料上的生长情况。结果DBM的孔径明显较PLLA／CPPf的大，孔隙率高，体外构建后10hDBM组的细胞黏附率为（91．3±8．2）％，PLLA/CPPf组为（82．2±7．7）％，两者之间差异具有统计学意义（P〈0．05）。DBM组于术后第3天网孔间出现细胞外基质，且随着时间的推移，基质变得稠密，而PLLA／CPPf的细胞外基质鲜见；第10天的扫描电镜也证实DBM组的细胞在支架材料上数量多，且细胞外的基质分泌较多。结论DBM较PLLA／CPPf更适于BMSCs的黏附生长，是理想的组织工程支架材料。     

金属蛋白酶2、血管内皮生长因子和肿瘤抑制因子在人脑胶质瘤中的表达和临床意义

目的:探讨人脑胶质瘤中的金属蛋白酶2(MMP-2)、血管内皮生长因子(VEGF)和肿瘤抑制因子(P16)的表达。方法:应用免疫组化法检测55例胶质瘤组织中的MMP-2、VEGF和P16蛋白的表达,通过原位杂交检测MMP-2 mRNA的表达。结果:胶质瘤的恶性程度与MMP-2、VEGF表达和P16的缺失表达呈正相关,随着胶质瘤的恶性程度的增高而增加。结论:胶质瘤的恶性程度由多种因素决定。胶质瘤中MMP-2含量越高,肿瘤细胞在浸润的过程中突破血脑屏障的能力越强;VEGF的表达增加,肿瘤的血液供应越丰富,恶性程度越高。P16蛋白缺失率高,组织学分化程度低,在一定程度上反映了胶质瘤细胞的恶性生物学行为。     

Broncho-alveolar Lavage Matrix Metalloproteases as a Sensitive Measure of Bronchiolitis Obliterans

Bronchiolitis obliterans (BO) is a survival-limiting factor in lung transplantation. There are no common BO markers in use. Since BO is associated with extracellular matrix remodeling, we asked whether matrix metalloproteases (MMPs) and their tissue inhibitors (TIMPs) could serve as BO markers. In 72 lung transplant patients (34 BO syndrome (BOS) 0, 15 BOS 0-p, and 23 BOS 1) serum and broncho-alveolar lavage (BAL) MMP and TIMP levels were examined by ELISA. The BAL cell counts were additionally analyzed. The serum MMP-2, MMP-8, MMP-9 and TIMP-2 levels were not different in all groups. In contrast, the BAL MMP-8, -9 and TIMP-1 levels were significantly elevated in BOS 0-p (p = 0.003; p = 0.007; p = 0.0003, respectively) and BOS 1 (p = 0.003; p = 0.001; p = 0.0004, respectively) as compared to BOS 0 patients. The BAL MMP-8, -9 and TIMP-1 levels were significant predictors of BOS 0-p (p = 0.01; p = 0.01; p = 0.01, respectively) and BOS-1 (p = 0.007; p = 0.01; p = 0.006, respectively) in receiver operating characteristic analysis. Except for BAL macrophages that were significantly decreased in BOS 0-p versus BOS 0 patients; other cell counts were not different between the groups. BAL MMP-8, -9 and TIMP-1 might be useful markers to detect BO in lung transplant patients.     

基质金属蛋白酶及其抑制物对葡萄胎恶变的预测价值研究

目的　探讨基质金属蛋白酶 (MMPs)及其抑制物TIMPs在葡萄胎恶变预测中的价值。方法　采用免疫组化SP法测定 39例葡萄胎 (其中 11例发生恶变 )和 17例正常相同孕周的绒毛组织中MMP 2、MMP 9、TIMP 1、TIMP 2的表达及分布。结果　正常绒毛组织、葡萄胎组织的滋养细胞胞浆中MMP 2、MMP 9、TIMP 1、TIMP 2均有表达。MMP 2、MMP 9在葡萄胎发生恶变组的表达明显强于正常绒毛组和葡萄胎未发生恶变组 ,而TIMP 1,TIMP 2在正常绒毛组和葡萄胎组之间表达无显著性差异。MMP 2 /TIMP 2、MMP 9/TIMP 1在葡萄胎恶变组织中的表达强于在正常绒毛组织的表达。结论　在葡萄胎清宫组织中进行MMP 2、MMP 9的检测 ,有望成为判断葡萄胎日后恶变的一项预测指标     

RF refocused echoes of J-coupled spin systems: effects on RARE-based spectroscopic imaging.

A numerical simulation tool was developed to calculate the echo amplitudes of J-coupled resonances within a series of radiofrequency (RF) refocused echoes. The signal modulation due to J-coupling in rapid acquisition with relaxation enhancement (RARE) is suppressed only when the inverse of the pulse interval (tau) is large compared to both the chemical shift (CS) difference (Deltadelta) of the coupled spins and the coupling constant. In contrast, the echo amplitudes in ultrafast low-flip-angle RARE (U-FLARE) oscillate around a quasi-steady-state value that is greater than zero (neglecting relaxation and diffusion) even when Deltadelta > 1/tau. The flip-angle distribution over the measured slice caused by the use of Gaussian-shape slice-selective refocusing pulses further reduces the echo oscillations. When the pulse interval falls short of the fast pulse rate regime, spectroscopic U-FLARE provides an improved spatial impulse response in the phase-encoding (PE) direction compared to spectroscopic RARE.     

Performance in population models for count data,part II: A new SAEM algorithm

Analysis of count data from clinical trials using mixed effect analysis has recently become widely used. However, algorithms available for the parameter estimation, including LAPLACE and Gaussian quadrature (GQ), are associated with certain limitations, including bias in parameter estimates and the long analysis runtime. The stochastic approximation expectation maximization (SAEM) algorithm has proven to be a very efficient and powerful tool in the analysis of continuous data. The aim of this study was to implement and investigate the performance of a new SAEM algorithm for application to count data. A new SAEM algorithm was implemented in MATLAB for estimation of both, parameters and the Fisher information matrix. Stochastic Monte Carlo simulations followed by re-estimation were performed according to scenarios used in previous studies (part I) to investigate properties of alternative algorithms (Plan et al., 2008, Abstr 1372 []). A single scenario was used to explore six probability distribution models. For parameter estimation, the relative bias was less than 0.92% and 4.13% for fixed and random effects, for all models studied including ones accounting for over- or under-dispersion. Empirical and estimated relative standard errors were similar, with distance between them being <1.7% for all explored scenarios. The longest CPU time was 95 s for parameter estimation and 56 s for SE estimation. The SAEM algorithm was extended for analysis of count data. It provides accurate estimates of both, parameters and standard errors. The estimation is significantly faster compared to LAPLACE and GQ. The algorithm is implemented in Monolix 3.1, (beta-version available in July 2009).     

胶原凝胶复合骨胶原基质(BCM)负载关节软骨细胞的实验研究

目的 探讨胶原凝胶包埋软骨细胞接种BCM支架的三维培养对软骨细胞生长及功能的影响.方法 将胶原凝胶包埋的关节软骨细胞接种BCM支架并在体外培养,应用倒置相差显微镜和扫描电镜观察软骨细胞的粘附、生长和增殖情况,培养14d,行苏木精-伊红、甲苯胺蓝染色观察软骨组织形成情况.结果 软骨细胞在支架上粘附、生长和增殖良好,体外培养14d能形成较成熟的软骨组织.结论 胶原凝胶复合BCM支架具有良好的细胞相容性,可作为负载生长因子的载体.     

Parallel imaging reconstruction for arbitrary trajectories using k-space sparse matrices (kSPA).

Although the concept of receiving MR signal using multiple coils simultaneously has been known for over two decades, the technique has only recently become clinically available as a result of the development of several effective parallel imaging reconstruction algorithms. Despite the success of these algorithms, it remains a challenge in many applications to rapidly and reliably reconstruct an image from partially-acquired general non-Cartesian k-space data. Such applications include, for example, three-dimensional (3D) imaging, functional MRI (fMRI), perfusion-weighted imaging, and diffusion tensor imaging (DTI), in which a large number of images have to be reconstructed. In this work, a systematic k-space-based reconstruction algorithm based on k-space sparse matrices (kSPA) is introduced. This algorithm formulates the image reconstruction problem as a system of sparse linear equations in k-space. The inversion of this system of equations is achieved by computing a sparse approximate inverse matrix. The algorithm is demonstrated using both simulated and in vivo data, and the resulting image quality is comparable to that of the iterative sensitivity encoding (SENSE) algorithm. The kSPA algorithm is noniterative and the computed sparse approximate inverse can be applied repetitively to reconstruct all subsequent images. This algorithm, therefore, is particularly suitable for the aforementioned applications.