SARS病毒中S蛋白的hAPN受体接合功能域分析(英文)

目的:获得SARS冠状病毒S蛋白与CD13相互作用的信息,发现其可能的配体-受体作用区域和结合位点,为SARS蛋白功能研究以及设计抗SARS药物和疫苗提供线索。方法:在比较基因组学的基础上,通过运用多序列比对、同源性分析和进化分析等手段预测并确定SARS冠状病毒S蛋白与CD13相互作用的区域和结合位点,并用分子模拟和分子对接分析的方法模建S蛋白与CD13在预测区域的相互作用。结果:获得了SARS冠状病毒S蛋白与CD13相互作用的信息,发现了一个冠状病毒S蛋白与CD13相互作用的功能域,以及位于此功能域中的4个可能的相互作用的位点。分子模拟验证了其中一个可能的相互作用的位点。结论:CD13可能是SARS冠状病毒S蛋白结合的一个靶点,它们之间的相互作用可能是SARS病毒感染的途径之一。同时,本研究也为运用生物信息方法寻找蛋白质作用靶点的线索提供了一种策略。     

Identification of probable genomic packaging signal sequence from SARS—CoV genome by bioinformatics analysis

AIM:To predict the probable genomic packaging signal of SARS-CoV by bioinformatics analysis. The derived packaging signal may be used to design antisense RNA and RNA interfere (RANi) drugs treating SARS. methods: Based on the studies about the genomic packaging signals of MHV and BCoV, especially the information about primary and secondary structures, the putative genomic packaging signal of SARS_CoV were analyzed by using bioinformatic tools. Multi-alignment for the genomic sequences was performed among SARS-CoV,MHV,BCoV, PEDV and HCoV 229E. Secondary structures of RNA sequences were also predicted for the identification fo the possible genomic packaging signals. Meanwhile, the N and M proteins of all five viruses were analyzed to study the evolutionary relationship with genomic packaging signals. RESULTS: The putative genomic packaging signal of SARS-CoV locates at the 3′ end of ORF1b near that of MHV and BCoV, where is the most variable region of this gene. The RNA secondary structure of SARS-CoV genomic packaging signal is very similar to that of MHV and BCoV. The same result was also obtained in studying the genomic packaging signals of PEDV and HCoV 229E. Further more, the genomic sequence multi-alignment indicated that the locations of packaging signals of SARS-CoV, PEDV, and HCoV overlaped each other. It seems that the mutation rate of packaging signal sequences is much higher than the N protein, while only subtle variations for the M protein. CONCLUSIONS: The probable genomic packaging signal of SARS-CoV is analogous to that of MHV and BCoV, with the corresponding secondary RNA structure locating at the similar region of ORF1b. The positions where genomic packaging signals exist have suffered rounds of mutations, which may influence the primary structures of the N and M proteins consequently.     

Expression of malaria transmission-blocking vaccine antigen Pfs25 in Pichia pastoris for use in human clinical trials

In previously published studies, Saccharomyces cerevisiae recombinant protein expression systems have been employed to express the malaria parasite antigen Pfs25, a candidate transmission-blocking vaccine antigen against Plasmodium falciparum malaria. However, despite having been in two Phase 1 trials, the recombinant Pfs25 so produced (previously called TBV25H) exists as a mixture of two monomeric protein conformational forms, Pfs25H-A and Pfs25H-B. In this study, we optimized the expression and purification of the two Pfs25H conformers in S. cerevisiae, and characterized their biochemical and antigenic properties, immunogenicities, and transmission-blocking activities. Pfs25H-A is apparently homogeneous, and has the correct conformation as measured by monoclonal antibody recognition. It is, however, expressed at a low yield of only 0.19mg/l. By contrast, Pfs25H-B is produced as a heterogeneous population of molecules that do not seem to have the correct conformation. Nonetheless, both forms appear equally effective in their ability to produce transmission-blocking antibodies in mice. To address the low yield seen with S. cerevisiae, we also expressed Pfs25 in Pichia pastoris. P. pastoris is apparently superior to S. cerevisiae in producing higher yield, immunologically more potent, biologically more active Pfs25H-A.     

Formaldehyde-induced gene expression in F344 rat nasal respiratory epithelium

Formaldehyde (FA), an occupational and environmental toxicant used extensively in the manufacturing of many household and personal use products, is known to induce squamous cell carcinomas in the nasal turbinates of rats and mice and squamous metaplasia in monkey noses. Tissue responses to FA include a dose dependent epithelial degeneration, respiratory cell hypertrophy, and squamous metaplasia. The primary target for FA-induced toxicity in both rodents and monkeys is the respiratory nasal epithelium. FA increases nasal epithelial cell proliferation and DNA-protein crosslinks (DPX) that are associated with subsequent nasal cancer development. To address the acute effects of FA exposure that might contribute to known pathological changes, cDNA gene expression analysis was used. Two groups of male F344 rats received either 40 ul of distilled water or FA (400 mM) instilled into each nostril. Twenty-four hours following treatment, nasal epithelium was recovered from which total RNA was used to generate cDNA probes. Significance analysis of microarrays (SAM) hybridization data using Clontech Rat Atlas 1.2 arrays revealed that 24 of the 1185 genes queried were significantly up-regulated and 22 genes were significantly downregulated. Results for ten of the differentially expressed genes were confirmed by quantitative real time RT PCR. The identified genes with FA-induced change in expression belong to the functional gene categories xenobiotic metabolism, cell cycle, apoptosis, and DNA repair. These data suggest that multiple pathways are dysregulated by FA exposure, including those involved in DNA synthesis/repair and regulation of cell proliferation. Differential gene expression profiles may provide clues that could be used to define mechanisms involved in FA-induced nasal cancer.     

Correlation and simple linear regression

In this tutorial article, the concepts of correlation and regression are reviewed and demonstrated. The authors review and compare two correlation coefficients, the Pearson correlation coefficient and the Spearman rho, for measuring linear and nonlinear relationships between two continuous variables. In the case of measuring the linear relationship between a predictor and an outcome variable, simple linear regression analysis is conducted. These statistical concepts are illustrated by using a data set from published literature to assess a computed tomography-guided interventional technique. These statistical methods are important for exploring the relationships between variables and can be applied to many radiologic studies.     

Statistical validation based on parametric receiver operating characteristic analysis of continuous classification data

Rationale and Objectives. The accuracy of diagnostic test and imaging segmentation is important in clinical practice because it has a direct impact on therapeutic planning. Statistical validations of classification accuracy was conducted based on parametric receiver operating characteristic analysis, illustrated on three radiologic examples.

Materials and Methods. Two parametric models were developed for diagnostic or imaging data. Example 1: A semi-automated fractional segmentation algorithm was applied to magnetic resonance imaging of nine cases of brain tumors. The tumor and background pixel data were assumed to have bi-beta distributions. Fractional segmentation was validated against an estimated composite pixel-wise gold standard based on multi-reader manual segmentations. Example 2: The predictive value of 100 cases of spiral computed tomography of ureteral stone sizes, distributed as bi-normal after a nonlinear transformation, under two treatment options received. Example 3: One hundred eighty cases had prostate-specific antigen levels measured in a prospective clinical trial. Radical prostatectomy was performed in all to provide a binary gold standard of local and advanced cancer stages. Prostate-specific antigen level was transformed and modeled by bi-normal distributions. In all examples, areas under the receiver operating characteristic curves were computed.

Results. The areas under the receiver operating characteristic curves were: Example 1: Fractional segmentation of magnetic resonance imaging of brain tumors: meningiomas (0.924–0.984); astrocytomas (0.786–0.986); and other low-grade gliomas (0.896–0.983). Example 3: Ureteral stone size for treatment planning (0.813). Example 2: Prostate-specific antigen for staging prostate cancer (0.768).

Conclusion. All clinical examples yielded fair to excellent accuracy. The validation metric area under the receiver operating characteristic curves may be generalized to evaluating the performances of several continuous classifiers related to imaging.     

温阳利水强心颗粒剂治疗慢性充血性心力衰竭60例临床疗效观察

"温阳利水强心颗粒剂"系我所在真武汤基础上,结合云南著名中医学家吴佩衡先生运用附子的经验,采用现代制剂工艺研制而成.具有温阳利水、强心益肾、通脉宁心之功,治疗慢性充血性心力衰竭(阳虚型).将100例符合要求病例随机分为治疗组60例,西药对照组40例进行对比观察,结果治疗组总有效率96.67%.对照组总有效率95%,治疗组与对照组P＞0.05,无显著性差异.中医舌脉总改善率治疗组53.33%,对照组32.5%,P＜0.05,有显著差异,说明温阳利水强心颗粒剂突出中医定性指标及辨证论治特色,不仅心功能得到有效改善,中医宏观疗效指标也得到明显改善,提高病人生存质量,减少心衰发作次数,显示了中药复方多环节、多靶点的整体调节优势.     

肺癌相关基因HLCDG1的克隆和表达分析

背景与目的：比较基因组杂交和微卫星多态性位点全基因组扫描结果显示肺癌患者在染色体3p、5q、6q、9p、10q、llp、13q、17p、19p等区域存在高频率的杂合性缺失,提示可能有多个未知的易感基因或抑癌基因与肺癌的发生、发展相关。本研究选用在mRNA差异显示研究中获得的在肺癌组织中表达下调且代表新基因的表达序列标签(expressed sequence tag,EST)LXDDl为进一步研究对象,克隆其全长cDNA。方法：采用Northern杂交验证LXDDl在肺癌中的表达差异。并用MTN(Multiple Tissue Northern Blots^TM)膜检测其在正常组织中的表达及其所代表基因的转录本大小;克隆其全长cDNA,并利用生物信息学对该序列进行初步分析;用差异RT-PCR检测新基因在肺癌组织、配对癌旁非癌组织、肺癌细胞系和其它肿瘤细胞系中的表达。结果：成功地克隆了一个在肺癌中表达下调的新基因。HLCDGl(human lung carcinoma deleted gene 1),GenBank登录号为AF447582,全长cDNA为3．113kb,预测其开放阅读框编码一个含166个氨基酸的跨膜蛋白质。通过电子-聚合酶链反应(electric-polymerase chain reaction,e-PCR)将该基因定位于5q33。结论：HLCDGl基因是一个在肺癌中表达下调的新基因。这提示HLCDGl可能与肺癌的发生、发展相关。     

Role of placental tissues in the intrauterine transmission of hepatitis B virus

OBJECTIVE: The purpose of this study was to determine the mechanism of intrauterine transmission of hepatitis B virus. STUDY DESIGN: Placental tissues from 158 pregnant women who tested positive for hepatitis B surface antigen were examined for hepatitis B virus markers, Fc gamma receptors, and hepatitis B surface antigen-anti-hepatitis B surface antigen in different layers of cells. RESULTS: It was shown that the hepatitis B virus infection rate among different layers of placental cells gradually decreased from the maternal side to the fetal side. Furthermore, the closer the infected cell layer was to the fetal side, the higher the risk of intrauterine hepatitis B virus infection. Fc gamma receptors were found on cells of both hepatitis B surface antigen positive and negative placentas; Fc gamma receptors III were found on trophoblastic cells and villous mesenchymal cells, and Fc gamma receptors II were found on only villous mesenchymal cells. Hepatitis B surface antigen-antibodies to hepatitis B surface antigen was detected in the cytoplasm and on the membrane of trophoblastic cells and villous mesenchymal cells in 2 hepatitis B surface antigen-positive placentas. CONCLUSION: The results support the hypothesis that intrauterine hepatitis B virus transmission could be caused through "cellular transfer" in the placenta. One of the means of cellular transfer could be through Fc gamma receptor III-mediated entry of hepatitis B surface antigen-antibodies to hepatitis B surface antigen into cells.     

主要组织相容性复合物Ⅱ类分子转录激活因子核酶的克隆及其活性

目的探讨主要组织相容性复合物(MHC)Ⅱ类分子转录激活因子(CⅡTA)核酶抑制MHCⅡ类分子的表达。方法设计并合成针对人类CⅡTA的一组核酶,通过体外制备和活性鉴定,筛选出活性较高的核酶一Rz464。将Rz464克隆到真核表达载体pIRES2-EGFP,简称为pRz464,并稳定转染Daudi细胞株(pRzA64一D),流式细胞术检测经典的MHCⅡ(HLA-DR、-DP、-DQ)类抗原表达,RT—PCR检测CⅡTA mRNA水平。结果 pRz464-D与无关核酶组比较,HLA—DR、-DP、-DQ抗原表达分别降低了88．4％、83．5％、93．4％;同时CⅡTA的mRNA含量明显减少。结论提示抗CⅡTA锤头状核酶抑制了自身mRNA含量,从而阻止了其调控的MHCⅡ类分子的相应表达。