Development of immunofiltration assay by light addressable potentiometric sensor with genetically biotinylated recombinant antibody for rapid identification of Venezuelan equine encephalitis virus

A genetically biotinylated single chain fragment variable antibody (scFv) against Venezuelan equine encephalitis virus (VEE) was applied in a system consisting of an immunofiltration enzyme assay (IFA) with a light addressable potentiometric sensor (LAPS) for the rapid identification of VEE. The IFA involved formation of an immunocomplex sandwich consisting of VEE, biotinylated antibody, fluoresceinated antibody and streptavidin, capture of the sandwich by filtration on biotinylated membrane, and labeling of the sandwich by anti-fluorescein urease conjugate. The concentration ratio of biotinylated to fluoresceinated antibodies was investigated and optimized. By the IFA/LAPS assay, the limit of detection (LOD) of VEE was approximately 30 ng/ml, similar to that achieved when chemically biotinylated monoclonal antibody (mAb) was applied. Total assay variance of the IFA/LAPS assay for both intra- and inter-assay precision was less than 20%. Assay accuracy was measured by comparing VEE concentrations estimated by IFA/LAPS standard curve to those obtained by conventional protein assay. VEE concentrations were found to differ by no more than 10%. The IFA/LAPS assay sensitivity was approximately equal to that of a conventional enzyme-linked immunosorbent assay (ELISA) utilizing polystyrene plates and a chromogenic substrate; however, less time and effort were required for performance of the IFA/LAPS assay. More importantly, use of genetically biotinylated scFv in the IFA/LAPS assay obviates the need for chemical biotinylation of antibody with resultant possible impairment of the antigen-binding site. Furthermore, the potential for batch-to-batch variability resulting from inequality in the number of biotin molecules labeled per antibody molecule is eliminated.     

脑血流断层显像Bullseye显示

为了探讨用Bullseye显示脑血流灌注显像数据的可能性,对8例典型脑梗塞病例及15例脑血流断层显像常规分析可疑病例的脑血流断层显像的横断面数据进行Bullscye显示,结果8例典型病人病灶用普通Bullseye即显示良好;常规分析可疑病例病变用普通Bullseye 8例显示良好,变黑Bullseye 13例显示出病灶;结果提示利用Bullseye显示脑血流灌注显像数据的可能。     

Protection from pathogenic SIV challenge using multigenic DNA vaccines

To assess DNA immunization as a strategy for protecting against HIV infection in humans, we utilized SIVmne infection of Macaca fascicularis as a vaccine challenge model with moderate pathogenic potential. We compared the efficacy of DNA immunization alone and in combination with subunit protein boosts. All of the structural and regulatory genes of SIVmne clone 8 were cloned into mammalian expression vectors under the control of the CMV IE-1 promoter. Eight M. fascicularis were immunized twice with 3 mg of plasmid DNA divided between two sites; intramuscular and intradermal. Four primed macaques received a further two DNA immunizations at weeks 16-36, while the second group of four were boosted with 250 microg recombinant gp160 plus 250 microg recombinant Gag-Pol particles formulated in MF-59 adjuvant. Half of the controls received four immunizations of vector DNA; half received two vector DNA and two adjuvant immunizations. As expected, humoral immune responses were stronger in the macaques receiving subunit boosts, but responses were sustained in both groups. Significant neutralizing antibody titers to SIVmne were detected in one of the subunit-boosted animals and in none of the DNA-only animals prior to challenge. T-cell proliferative responses to gp160 and to Gag were detected in all immunized animals after three immunizations, and these responses increased after four immunizations. Cytokine profiles in PHA-stimulated PBMC taken on the day of challenge showed trends toward Thl responses in 2/4 macaques in the DNA vaccinated group and in 1/4 of the DNA plus subunit vaccinated macaques; Th2 responses in 3/4 DNA plus subunit-immunized macaques; and Th0 responses in 4/4 controls. In bulk CTL culture, SIV specific lysis was low or undetectable, even after four immunizations. However, stable SIV Gag-Pol- and env-specific T-cell clones (CD3+ CD8+) were isolated after only two DNA immunizations, and Gag-Pol- and Nef-specific CTL lines were isolated on the day of challenge. All animals were challenged at week 38 with SIVmne uncloned stock by the intrarectal route. Based on antibody anamnestic responses (western, ELISA, and neutralizing antibodies) and virus detection methods (co-culture of PBMC and LNMC, nested set PCR- of DNA from PBMC and LNMC, and plasma QC-PCR), there were major differences between the groups in the challenge outcome. Surprisingly, sustained low virus loads were observed only in the DNA group, suggesting that four immunizations with DNA only elicited more effective immune responses than two DNA primes combined with two protein boosts. Multigenic DNA vaccines such as these, bearing all structural and regulatory genes, show significant promise and may be a safe alternative to live-attenuated vaccines.     

迷走神经刺激对家兔高血钾时心室肌单相动作电位及心室肌细胞跨膜电位的影响

本文观察了电刺激迷走神经对家兔商血钾时心室肌单相动作电位(MAP)及单个心室肌细胞跨膜电位(TMP)的影响。结果表明,迷走神经刺激可以改善高血钾引起的心室内传导阻滞,使单相动作电位振幅(MAPA)、单相动作电位0相最大上升速率(MVmax)增加,单相动作电位时程(MAPD)延长,亦使单个心室肌细胞静息电位(RP)、动作电位振幅(APA)和0相最大上升速率(Vmax)增加,动作电位时程(APD)延长。另外,两种记录方法在同一部位的MAPD与APD完全一致。     

应用微阵列初步分析髓母细胞瘤的基因表达谱

目的　应用微阵列技术研究髓母细胞瘤的分子发病机理。方法　收集新鲜髓母细胞瘤 4例及正常脑组织 1份的组织标本 ,提取总 RNA,逆转录成 32 P标记的 c DNA探针 ,与 Atlas人肿瘤芯片杂交 ,通过放射自显影获得基因谱 ,应用 Atlas Image TM1.0 1a分析。结果　与正常脑组织相比 ,髓母细胞瘤下调基因 6个 ,上调基因 35个 ;逆转录 -聚合酶链反应技术验证结果与芯片检测结果相符。除少数基因外 ,大部分基因的表达趋势与肿瘤生物学特性相符。结论　髓母细胞瘤是与星形细胞起源胶质瘤具有不同分子发病机理的多基因病变 ,不同基因之间可能存在复杂的相互作用和联系 ,值得进一步研究。     

基于线性调频信号的高帧率超声成像系统

基于有限衍射波束的高帧率超声成像系统能实现快速成像，但由于仅通过一次发射事件成像，信噪比较低，本研究针对该问题提出一种改进方案。它采用合成孔径雷达中所使用的线性调频信号作为激励信号，在接收端则利用线性调频信号的脉冲压缩比等于信号的时间带宽积的特征，将接收信号通过匹配滤波器处理。结果表明该方案不仅能显著提高成像系统的信噪比，改善重构图像的质量，增加成像深度，而且不损失分辨率。     

内痔粘膜及血管上皮细胞VEGF/FGF2的表达与内痔分期的相关性分析

目的 通过观察人体内痔不同分期粘膜及血管内皮细胞生长因子（VEGF）及碱性成纤维细胞生长因子（FGF2）的表达，探讨内痔的发生及发展机制。 方法 收集南方医院肛肠科门诊手术切除的Ⅰ、Ⅱ、Ⅲ期内痔标本134例（Ⅰ期42例，Ⅱ期45例，Ⅲ期47例），内痔周围正常肠壁组织40例作为对照，采用HE染色观察组织的病理学变化，采用免疫组织化学方法检测血管内皮细胞VEGF及FGF2的表达。 结果 正常组及Ⅰ期内痔黏膜层被覆上皮完整，未见扩张血管；Ⅱ期内痔黏膜层被覆上皮破坏，黏膜肌层破坏，黏膜层内见新生血管；Ⅲ期内痔黏膜层被覆上皮破坏，见血管管壁增厚迂曲，管腔扩张；与正常粘膜成纤维细胞相比VEGF在粘膜层成纤维细胞表达水平明显升高，并随分期增高而增高（F=883.961，P<0.01），FGF2也存在相同表达（F=656.013，P<0.01）；与正常组相比VEGF在血管内皮细胞表达水平明显升高，并随分期增高而增高（F=776.561，P<0.01），FGF2在血管内皮细胞的表达水平存在相同趋势（F=1066.458，P＜0.01）。 结论 VEGF及FGF2在内痔的形成过程中具有促进血管内皮细胞和粘膜下成纤维细胞增生的作用，同时可作为内痔发生发展的分子标志物。     

电化学共沉积制备有机高聚物/钙磷复合陶瓷膜层--Ⅱ XPS、SIMS表征及力学性能研究

通过电化学共沉积方法制备具有生物活性的有机高聚物／钙磷陶瓷复合膜层。用XPS、SIMS等对复合膜层的化学组分进行表征，证明少量有机高聚物可能在分子层次上掺杂形成有机高聚物／羟基磷灰石复合膜层。对电沉积HAP陶瓷膜层进行微刮痕实验表明，陶瓷膜层与金属基体的结合力得到显著改善。