尾加压素II与糖尿病

尾加压素II(urotensin II，UII)最早是从鱼尾部下垂体中分离出的调节肽，近来已从人体中克隆出来，并发现体内一种孤立的G蛋白偶联受体GPR14是其特异性受体。UII与GPR14结合后，参与许多生物学效应，如调节内分泌，调节渗透压平衡，调节胃肠道平滑肌及心血管收缩功能等，是迄今体内最强的缩血管活性肽。UII不仅与许多人类心血管疾病如高血压，充血性心力衰竭（CHF），冠心病和动脉粥样硬化有关，而且研究发现，糖尿病患者血液中UII含量升高。初步研究表明,UII的基因多态性和2型糖尿病的发生有关；尾加压素II还可抑制胰岛素的释放。     

Opa相互作用蛋白5在胰腺癌中的表达及其对PANC-1细胞增殖的影响

目的探索Opa相互作用蛋白5(OIP5)在胰腺癌中的表达及其对PANC-1细胞增殖的影响。方法通过数据库分析OIP5在胰腺癌组织及癌旁组织中的表达;用实时定量PCR(RT-qPCR)和蛋白印迹法(Western blot)分别检测人胰腺癌细胞系MIAPaCa-2、PANC-1、KP-3、BxPC-3细胞中OIP5 mRNA和蛋白表达;构建OIP5基因沉默质粒的慢病毒(pGCSIL-shOIP5)和对照质粒慢病毒(pGCSIL-shCtrl),分别感染PANC-1细胞,分为OIP5基因沉默组和shCtrl对照组,5 d后采用RT-qPCR和Western blot测定慢病毒敲低效率,流式细胞计量术检测细胞凋亡;OIP5基因沉默组和shCtrl对照组连续5 d进行MTT检测和细胞计数;OIP5基因沉默组和shCtrl对照组孵育10 d形成集落,Giemsa染色分别集落总数。结果胰腺癌中OIP5 mRNA表达显著高于正常胰腺组织(P<0.05),OIP5高表达患者的总存活率显著低于OIP5低表达患者(P<0.05),且其无病生存率也显著降低(P<0.05);OIP5在MIAPaCa-2、PANC-1和KP-3中表达较高,而在BxPC-3细胞系中的表达较低;MTT检测结果显示OIP5沉默在第4和第5天显著降低了PANC-1细胞的增殖速率(P<0.01);OIP5沉默后细胞集落数(平均为9个)显著低于shCtrl对照组中的数量(平均为40个)(P<0.01);OIP5沉默后PANC-1细胞凋亡比例为8.3%显著高于shCtrl的4.5%(P<0.01)。结论OIP5在胰腺癌细胞系中异常高表达,OIP5基因可调控胰腺癌PANC-1细胞的增殖、凋亡以及集落形成,提示OIP5可能在胰腺癌发病机制中作为癌基因发挥作用,从而为胰腺癌的靶向治疗提供了潜在的生物标志物。     

SSAHA: a fast search method for large DNA databases

We describe an algorithm, SSAHA (Sequence Search and Alignment by Hashing Algorithm), for performing fast searches on databases containing multiple gigabases of DNA. Sequences in the database are preprocessed by breaking them into consecutive k-tuples of k contiguous bases and then using a hash table to store the position of each occurrence of each k-tuple. Searching for a query sequence in the database is done by obtaining from the hash table the "hits" for each k-tuple in the query sequence and then performing a sort on the results. We discuss the effect of the tuple length k on the search speed, memory usage, and sensitivity of the algorithm and present the results of computational experiments which show that SSAHA can be three to four orders of magnitude faster than BLAST or FASTA, while requiring less memory than suffix tree methods. The SSAHA algorithm is used for high-throughput single nucleotide polymorphism (SNP) detection and very large scale sequence assembly. Also, it provides Web-based sequence search facilities for Ensembl projects.     

Vancomycin-resistant enterococcal bacteremia: comparison of clinical features and outcome between Enterococcus faecium and Enterococcus faecalis.

BACKGROUND AND PURPOSE: Vancomycin-resistant enterococci (VRE) have emerged as important nosocomial pathogens. This study was conducted to clarify the clinical features and outcome of patients with vancomycin-resistant enterococcal bacteremia. METHODS: Patients with vancomycin-resistant enterococcal bacteremia treated at a medical center in northern Taiwan between November 1998 and July 2006 were reviewed. Clinical and bacteriological characteristics of Enterococcus faecium and Enterococcus faecalis were compared. RESULTS: Twelve patients (6 males and 6 females) were included for analyses. The mean age was 69.3 years (range, 40 to 86 years), and 8 cases (66.7%) were older than 65 years. All patients had underlying disease. Two patients received total hip replacement before development of VRE bacteremia. Twelve patients had prior exposure to broad-spectrum antimicrobial therapy. Ten patients had prior intensive care unit stay and prior mechanical ventilation before VRE bacteremia. All of the patients (n = 12) had an intravascular catheter in place. Bacteremia was caused by E. faecalis in 4 patients and by E. faecium in eight. The portals of entry included urinary tract (8.3%), skin, soft tissue and bone (41.7%) and unknown sources (50.0%). E. faecium showed a higher rate of resistance to ampicillin and teicoplanin than E. faecalis (87.5% vs 0.0%, p=0.01). The 60-day mortality rate was higher in patients with E. faecium bacteremia than E. faecalis bacteremia (62.5% vs 0.0%), although statistical significance was not obtained (p=0.08). CONCLUSIONS: VRE bacteremia may have an impact on the mortality and morbidity of hospitalized patients. Patients with bacteremia caused by vancomycin-resistant E. faecium had a grave prognosis, especially immunosuppressed patients. The prudent use of antibiotics and strict enforcement of infection control may prevent further emergence and spread of VRE.     

不同给药途径的腺苷预处理对大鼠缺血再灌注心肌的保护

Objective To evaluate the effect on myocardial protection of adenosine preconditioning in different route of administration through right jugular vein and left ventricle.Methods 48 SD rats were randomly divided into ischemia reperfusion group(blank control),ischemic preconditioning group(IP,positive control),adenosine venous infusion group,adenosine in ventricular group,normal saline(NS)venous infusion group(negative control I)and NS in ventricular group(negative control Ⅱ).The ischemia reperfusion rats model were established in vivo,and then changes of heart function,serum cardiac troponin T (cTnT),superoxide dismutase(SOD),malondialdehyde(MDA)and expression of nuclear factor KB(NF-kB) were observed.Results SOD in IP[(208.63±23.88)U/ml],adenosine venous infusion group [(178.27±11.56) U/ml]and adenosine in ventricular group[(191.31±28.14)U/ml]were significantly higher than that in the ischemia reperfusion group[(145.05±23.18)U/ml](P<0.05),cTnT,MDA and expression of NF-kB were lower than that in the ischemia reperfusion group (P<0.05).Heart function was significantly better than that in the ischemia reperfusion group(P<0.05);SOD in adenosine in ventricular group was significantly higher than that in adenosine venous infusion group(P<0.05).cTnT,MDA and expression of NF-kB were lower than that in adenosine venous infusion group (P<0.05).Conclusion Adenosine preconditioning may mimic protective effect of ischemic preconditioning. The effect on myocardial protection of adenosine in ventricular group was better than that of adenosine venous infusion group.     

Experimental determination of the anisotropy function for the model 200 103Pd "light seed" and derivation of the anisotropy constant based upon the linear quadratic model

Since the publication of the AAPM Task Group 43 report in 1995, Model 200 103Pd seed, which has been widely used in prostate seed implants and other brachytherapy procedures, has undergone some changes in its internal geometry resulting from the manufacturer's transition from lower specific activity reactor-produced 103Pd ("heavy seeds") to higher specific activity accelerator-produced radioactive material ("light seeds"). Based on previously reported theoretical calculations and measurements, the dose rate constants and the radial dose functions of the two types of seeds are nearly the same and have already been reported. In this work, the anisotropy function of the "light seed" was experimentally measured and an averaging method for the determination of the anisotropy constant from distance-dependent values of anisotropy factors is presented based upon the continuous low dose rate irradiation linear quadratic model for cell killing. The anisotropy function of Model 200 103Pd "light seeds" was measured in a Solid Water phantom using 1 X 1 x 1 mm micro LiF TLD chips at radial distances of 1, 2, 3, 4, 5, and 6 cm and at angles from 0 to 90 degrees with respect to the longitudinal axis of the seeds. At a radial distance of 1 cm, the measured anisotropy function of the 103Pd "light seed" is considerably lower than that of the 103Pd "heavy seed" reported in the TG 43 report. Our measured values at all radial distances are in excellent agreement with the results of a Monte Carlo simulation reported by Weaver, except for points along and near the seed longitudinal axis. The anisotropy constant of the 103Pd "light seed" was calculated using the linear quadratic biological model for cell killing in 30 clinical implants. For the model 200 "light seed," it has a value of 0.865. However, our biological model calculations lead us to conclude that if the anisotropy factors of an interstitial brachytherapy seed vary significantly over radial distances anisotropy constant should not be used as an approximation for anisotropy characteristics of a brachytherapy seed.     

模拟退火算法在图像配准中的应用

近年来 ,脑功能成像技术发展迅速 ,已在脑科学研究中占有重要地位。研究中通常需要将同一被试的多种模式成像结果或同一模式的时间序列结果结合起来分析 ,首先要解决的问题就是几幅图像的严格对齐问题 ,即所谓的图像配准。在模拟退火算法和其它工作的基础之上 ,较好的解决了图像配准中的连续变量全局优化问题 ,通过基于点的配准方法 ,实现了时间序列脑功能图像的高精度配准。     

以傅立叶频谱滤波为手段的振荡电位波形分离方法

为克服传统方法(Calliper-square)和带通放大器在测量振荡电位(OPs)中的不足,应用计算机傅立叶频谱滤波技术,从ERG中分离出振荡电位波形。分离出的OPs能够摆脱a-波,b-波对它的影响而独立地表现出来,使得对OPs的测量变得直观、方便、准确,并把对ERG、OPs的研究,从时域分析扩展到频域分析。     

路氏乳杆菌JCM1081黏附相关蛋白的初步鉴定

目的研究路氏乳杆菌(Lactobacillus reuteri,也称罗伊氏乳杆菌)JCM1081菌体表面蛋白对其黏附HT-29细胞的影响。方法将路氏乳杆菌JCM1081菌体进行胰蛋白酶、蛋白酶K处理;用氯化锂和盐酸胍对乳杆菌表面的蛋白进行抽提,进行SDS-PAGE后与黏蛋白受体进行Western blot,并对杂交阳性蛋白进行质谱分析鉴定。结果路氏乳杆菌JCM1081菌体经胰蛋白酶、蛋白酶K处理后,其对HT-29细胞的黏附力显著下降(P<0．01);用氯化锂去除路氏乳杆菌JCM1081菌体外表面的S层蛋白后,路氏乳杆菌JCM1081对HT-29细胞的黏附力无显著变化;Western blot结果显示相对分子质量(Mr)为29×103和14×103的两种菌体表面蛋白与黏蛋白受体杂交中出现了强阳性;质谱分析结果显示29×103蛋白与路氏乳杆菌ATCC55730的h0793蛋白相似性高达71．1％。结论路氏乳杆菌JCM1081菌体表面的蛋白参与了乳杆菌的黏附,其中29×103和14×103的两种胞壁表面蛋白能够特异地识别黏蛋白受体并与之结合,29×103蛋白属ABC转运蛋白家族。