Poly（A）加尾-RNase H消化-RT-PCR法分析应激诱导生成5′端tRNA半分子

目的：建立一种简便、快速检测应激诱导细胞生成的5′端转移RNA（ tRNA）半分子的方法。方法提取应激诱导细胞RNA,用poly（ A）加尾酶在RNA分子3′端加尾后,加入与待测tRNA的3′端部分序列互补的简并DNA探针杂交,经RNase H消化与DNA探针互补的tRNA序列,再由oligo（ dT） n锚定引物进行逆转录获得互补DNA（ cDNA）,以5′端tRNA半分子和锚定引物的序列为PCR反应的上下游引物,PCR扩增检测5′端tRNA半分子。结果经poly（ A）加尾-RNaseH消化-RT-PCR-电泳等步骤,可以实现对5′端tRNA半分子的检测分析。结论 poly （ A）加尾-RNaseH消化-RT-PCR法的建立实现了5′端tRNA半分子的简便、快速检测分析,为tRNA半分子生物学功能研究和检测分析提供了工具。     

谷氨酰-脯氨酰-tRNA合成酶(EPRS)结构与功能的新认识

氨基酰-tRNA合成酶（ARS）催化特异的氨基酸结合到对应tRNA上,确保mRNA高精度地翻译为蛋白质.最近陆续报道ARS同时也在细胞基本生命活动如RNA运输、转录、翻译、免疫反应以及血管生成中充当重要的调节分子和活性成分.目前报道谷氨酰-脯氨酰-tRNA合成酶（EPRS）在具有催化谷氨酸和脯氨酸分别结合到不同tRNA上的功能之外,还可通过基因选择性沉默机制阻遏血浆铜蓝蛋白的表达,从而终止炎症反应等.本文就该酶结构与功能的研究新进展进行综述,并对其进行分子进化分析.     

大肠杆菌基因组水平蛋白质-RNA相互作用初步研究

目的初步研究大肠杆菌中基因组水平的蛋白质-RNA相互作用（protein-RNA interactions,PRI）。方法通过RNA酶消化细菌裂解液,提取与蛋白质相互作用的RNA片段,构建cDNA文库,进行高通量测序,并通过生物信息学分析获得与蛋白质结合的转录本。结果获得了与蛋白质结合的3193条转录本,涉及2234个mRNA、47个sRNA（small regulatory RNAs）、39个tRNA、11个rRNA以及862个基因间区（intergenic region,IGR）。结论初步获得大肠杆菌中与蛋白质相互作用的转录本信息,为进一步开展PRI研究提供了支持。     

前列腺癌中非编码RNA与雄激素受体信号间调控的研究进展

雄激素受体（androgen receptor,AR）及其下游信号在前列腺癌的发生发展中发挥着关键性的作用。微小RNA（microRNA,miRNA）和长链非编码RNA（long non-coding RNA,lncRNA）等非编码RNA不仅影响AR信号的调控网络,而且参与前列腺癌的发展进程。作者重点就前列腺癌中miRNA、lncRNA与AR信号间调控网络的研究进展进行综述。     

RNA干扰在组织特异性靶向性基因治疗中的研究进展

RNA干扰（RNA interference,RNAI）技术是一种有效的基因沉默技术,由于其高度特异性、高效性以及稳定性等特点,RNA干扰技术在肿瘤基因治疗研究中得到了广泛的应用。靶向性基因治疗是肿瘤生物治疗的一个重要研究方向。本文以RNA干扰技术在靶向性基因治疗中的研究进展进行综述。     

CLIP相关技术的研究进展

在真核生物基因表达的转录后调节中,RNA结合蛋白（ RBP）起着关键作用,很多RBP的异常与人类疾病的发生密切相关。自2000年的RNA免疫沉淀和芯片分析方法（ RNA immunoprecipitation with differential display or microarray analysis , RIP-ChIP）出现以来,人们开始就RBP与RNA相互作用进行了系统而广泛的研究。经过改良和发展,基于体内实时紫外交联免疫沉淀法（ ultraviolet crosslinking and immunoprecipitation , CLIP ）、交联免疫沉淀cDNA文库高通量测序法（ high-throughput sequencing of CLIP cDNA library , HITS-CLIP）、光催化核糖核苷增强交联和免疫沉淀法（ photoactivatable-ribonucleoside-enhanced crosslinking and immunprecipitation , PAR-CLIP）以及提高个别核苷酸分辨率交联和免疫共沉淀法（ individual nucleotide resolution CLIP , iCLIP）等RIP-ChIP衍生方法相继产生,使用这些方法,可以解析RBP的RNA识别特异性,而且通过与高通量测序技术结合,可以实现转录组尺度的RBP的靶序列的鉴定,分辨率也得到极大提高。该文就RNA与蛋白的相互作用的基本原理及其研究进展、相关技术存在的问题以及发展趋势进行简要综述。     

肾综合征出血热流行病学研究进展

汉坦病毒（Hantavimses,HV）属布尼亚病毒科（Bunyaviriclae）汉坦病毒属（Hantavirus）,为分节段的单股负链RNA病毒,基因组有大（L）、中（M）、小（S）3个片段组成,分别编码病毒RNA依赖的RNA多聚酶、病毒Gn、Gc糖蛋白以及核衣壳蛋白（NP）。在临床上主要引起欧亚地区的肾综合征出血热（Hemorrhagic Fever with Renal Syndrome,HFRS）和美洲的汉坦病毒肺综合征（Hantavirus Pulmonary Syndrome, HPS）。     

顺铂诱导肺腺癌A549细胞线粒体基因组及凋亡相关基因的差异表达

目的　探讨顺铂诱导肺腺癌A5 4 9细胞线粒体基因组及核凋亡相关基因的差异表达情况。方法　实验组A5 4 9细胞给予0 5 μg/ml顺铂作用 2 0h,同时设立空白对照组 ,用人线粒体基因组寡核苷酸芯片检测 2 6个靶基因的差异表达。用流式细胞技术分析细胞凋亡比例。结果　实验组A5 4 9细胞的细胞色素氧化酶亚单位Ⅰ(CoxⅠ)、12SrRNA以及半胱氨酸转运RNA(tRNA Cys)、天冬酰胺转运RNA(tRNA Asn)基因表达显著上调 ,促凋亡基因bax和另外 3个编码多肽基因、4个tRNA基因表达也有一定程度上调。实验组A5 4 9细胞凋亡率为 8 5 %± 0 78% ,显著高于对照组的 1 3%± 0 5 6 % (n=5 ,P <0 0 5 )。结论　顺铂诱导能使残存的A5 4 9细胞mtDNA编码的部分基因表达增强 ,并可能通过对bax基因表达的上调促进细胞凋亡。     

丙型肝炎病毒抗体联合核酸定量检测对HCV早期诊断的价值

目的探讨丙型肝炎病毒（ HCV）抗体联合病毒核酸（ HCV RNA）定量检测在丙型肝炎患者早期诊断中的价值。方法对我院收治的106例丙型肝炎病毒感染者血样分别测定HCV抗体、HCV RNA及丙氨酸氨基转移酶（ ALT）。结果106份血样检测中,酶联免疫吸附试验HCV抗体检测阳性87例（82.1%）,HCV金标法检测阳性69例（65.1%）,HCV RNA检测阳性80例（75.5%）,ALT阳性62例（58.5%）。HCV抗体检测阳性率明显高于HCV金标检测法（χ^27.863,P〈0.01）和ALT检测法（χ^214.115,P〈0.01）;HCV抗体联合HCV RNA检测总阳性率为100.0%,明显高于HCV抗体联合金标法检测（83.0%）和HCV抗体联合ALT检测（90.6%）（χ^219.670,P〈0.01;χ^210.495,P〈0.01）。结论 HCV抗体联合HCV RNA检测可显著提高HCV的早期诊断率,减少漏诊,有利于HCV的早期诊断。     

microRNA-胶质细胞调控网络在放射性脑损伤中的研究现状与展望

放射性脑损伤（radiation-induced brain injury,RBI）是头颈部肿瘤放射治疗后最为严重的并发症,发病机制复杂,临床病程不可逆且缺乏有效的治疗手段。胶质细胞激活是RBI的主要学说之一,靶向胶质细胞防治RBI是当前研究的热点。microRNA（miRNA）作为一种转录后调控因子,已被证实参与调节胶质细胞辐射敏感性,炎症类型转化,自噬,外泌体,长链非编码RNA（long non-coding RNA,lncRNA）、环状RNA（circular RNA,circRNA）等相关通路,从而介导中枢神经系统（central nervous system,CNS）疾病炎症级联损伤及神经功能修复的发生发展。因此,本文以RBI与miRNA-胶质细胞调控网络的联系为基点,概述了当前可用于防治RBI潜在的通路与方法。     

X射线诱导人肺腺癌A549细胞凋亡及线粒体DNA基因表达下调

目的 研究不同剂量X线对人肺腺癌A549细胞增殖及凋亡的影响，并检测其线粒体DNA（mtDNA）基因的差异表达。方法 以同步培养的未受照细胞为对照，8MVX线分别以2、4、6和8Gy的吸收剂量照射A549细胞，MTT比色法分析细胞增殖曲线；并于照射后24h，流式细胞仪测定细胞周期分布和凋亡率，电镜观察细胞超微结构，人mtDNA基因表达谱芯片检测靶基因的表达变化。结果X射线抑制A549细胞增殖，以4Gv为显著；随着照射剂量的增加，细胞凋亡率增加，G2／M期细胞比率增加，6和8Gy组表现出G2／M期阻滞，透射电镜下4Gy组可见凋亡的形态改变，8Gy组细胞近碎裂；X射线照射后mtDNA编码基因呈普遍下调表达，包括2Gy组的3种tRNA基因、4Gy组的2种tRNA基因和4种mRNA基因、6Gy组的6种tRNA基因和1种rRNA基因，8Gy组的2种tRNA基因。结论X射线可抑制A549细胞增殖，诱导细胞凋亡及mtDNA编码基因的普遍下调表达。随着辐射剂量的增加，剂量依赖性效应逐步减弱而解除。4Gy为体外研究的相对高效、安全剂量。     

X射线对人肺腺癌A549细胞增殖及线粒体DNA基因表达的影响

目的 研究X射线辐射对人肺腺癌A549细胞增殖及线粒体DNA(mtDNA)基因表达的影响。方法 8 MV X射线以4 Gy的吸收剂量照射A549细胞,照射后不同时间检测细胞周期分布和凋亡率,电镜下观察细胞超微结构,人mtDNA基因表达谱芯片检测靶基因的表达变化。结果 照射后12 h即出现G₂/M期的阻滞,凋亡率在照射后48 h达到峰值,透射电镜下可见凋亡的形态改变。X射线照射后mtDNA编码基因表达呈普遍下调,包括12 h组的1种tRNA和4种mRNA基因、24 h组的2种tRNA和4种mRNA基因、48 h组的13种mRNA和2种rRNA及4种tRNA基因、72 h组的11种mRNA和2种rRNA基因。结论 X射线辐射可导致A549细胞G₂/M期阻滞,mtDNA编码基因的普遍低表达可能和辐射诱导凋亡相关。     

一例肿瘤病人经6Gy γ线一次照射后尿中核苷的高效液相色谱分析

本文用高效液相色谱法对一例何杰金氏病病人全淋巴区~(60)Coγ线6Gy一次性照射后尿中核苷的变化进行了分析。照后尿中5种核苷(脱氧胞苷、脱氧尿苷、7-甲基鸟苷、肌苷、假尿苷)和一种游离的碱基(胸腺嘧啶)大幅度增加,随后在一周内逐渐减少。本文将这些结果联系辐射对核酸,特别是DNA,mRNA及tRNA的中间代谢的影响进行了讨论,并与一例急性放射病事故病人的尿中核苷变化作了比较。     

DNA analyses of the remains of the Prince Branciforte Barresi family

The five skeletons found buried in the church of Militello di Catania, Sicily, were tentatively identified by morphological analysis and historical reports as the remains of Prince Branciforte Barresi, two of his children, his brother and another juvenile member of the family (sixteenth and seventeenth centuries). In order to attempt to clarify the degree of relationships of the five skeletons, sex testing and mitochondrial DNA (mtDNA) sequence analysis of the hypervariable segments I and II (HV1 and HV2) of control region were performed. Moreover, the 9 bp-deletion marker of region V (COII/tRNA ^lys) was examined. Molecular genetic analyses were consistent with historical expectations, although they did not directly demonstrate that these are in fact the remains of the Prince and his relatives, due to the impossibility of obtaining DNA from living maternal relatives of the Prince. Received: 6 April 1999 / Accepted: 27 September 1999     

Mupirocin resistance screening of methicillin-resistant Staphylococcus aureus isolates at Madigan Army Medical Center

Mupirocin is an antibiotic used for eradication and infection control of methicillin-resistant Staphylococcus aureus (MRSA). Mupirocin binds to the bacterial isoleucyl tRNA synthetase, thus disrupting bacterial protein synthesis. Four hundred nine MRSA clinical isolates collected in 2006 and 2007 at Madigan Army Medical Center were screened for mupirocin resistance by E test and polymerase chain reaction; 7 MRSA isolates (1.7%) were found to be fully resistant to mupirocin (minimum inhibitory concentration [MIC] by E test: > 1,024 microg/mL), 10 isolates (2.4%) had MIC values of 1 to 32 microg/mL, while 392 MRSA isolates (95.9%) had MIC values of < 1 microg/mL. No trend of increased mupirocin resistance was found when compared with subsequent years. These results show that mupirocin remains a valid infection control measure due to its unique mechanism of action and the high susceptibility rate of MRSA isolates. In addition, rapid screening by polymerase chain reaction of MRSA shows promise in assessing the fully resistant mupirocin phenotype.     

Mitochondrial DNA sequence polymorphism, VO2max, and response to endurance training.

Mitochondrial DNA sequence variation was determined in 46 sedentary young adult males who took part in ergocycle endurance training programs in two laboratories to assess whether mitochondrial DNA variants were associated with individual differences in maximal oxygen uptake (VO2max) and its response to training. VO2max was obtained from a progressive ergocycle test to exhaustion. White blood cell mitochondrial DNA was characterized with the restriction fragment length polymorphism (RFLP) technique using 22 restriction enzymes and human mitochondrial DNA as a probe for hybridization. Multiple mitochondrial DNA variants were detected with 15 of the enzymes. Some subjects exhibited many RFLPs, while others showed no variation. These RFLPs (morphs) were generated by base substitutions located in gene regions coding for mitochondrial proteins as well as in the noncoding regions. Carriers of three mitochondrial DNA morphs, two in the subunit 5 of the NADH dehydrogenase gene and one in the tRNA for threonine, had a VO2max (ml.kg-1.min-1) in the untrained state significantly higher than noncarriers, while carriers of one mitochondrial DNA morph in subunit 2 of NADH dehydrogenase had a lower initial VO2max. Endurance training increased VO2max by a mean of 0.51 of O2, with individual differences ranging from gains of 0.06 to 1.03. After adjustment for training site and initial VO2max, a lower response was observed for three carriers of a variant in subunit 5 of the NADH dehydrogenase detected with HincII (mean gain of 0.28 I; P less than 0.05). These results suggest that sequence variation in mitochondrial DNA may contribute to individual difference in VO2max and its response to training.     

MRI – From basic knowledge to advanced strategies: Hardware

There have been remarkable advances in the hardware used for nuclear magnetic resonance imaging scanners. These advances have enabled an extraordinary range of sophisticated magnetic resonance MR sequences to be performed routinely. This paper focuses on the following particular aspects: (a) Magnet system. Advances in magnet technology have allowed superconducting magnets which are low maintenance and have excellent homogeneity and very small stray field footprints. (b) Gradient system. Optimisation of gradient design has allowed gradient coils which provide excellent field for spatial encoding, have reduced diameter and have technology to minimise the effects of eddy currents. These coils can now routinely provide the strength and switching rate required by modern imaging methods. (c) Radio-frequency (RF) system. The advances in digital electronics can now provide RF electronics which have low noise characteristics, high accuracy and improved stability, which are all essential to the formation of excellent images. The use of surface coils has increased with the availability of phased-array systems, which are ideal for spinal work. (d) Computer system. The largest advance in technology has been in the supporting computer hardware which is now affordable, reliable and with performance to match the processing requirements demanded by present imaging sequences.     

Non-contrast enhanced MR angiography: physical principles

Noncontrast-enhanced magnetic resonance angiography (NCE-MRA) methods have been demonstrated in anatomies throughout the body. Previously established NCE-MRA techniques suffered from long scan times or low sensitivity. Advances in hardware and software have made NCE-MRA scan times clinically feasible. Recent concerns over the safety of gadolinium-based contrast material combined with the expense of the material and its administration have generated a demand for NCE-MRA. In response, several new NCE-MRA methods have been developed. The physical mechanisms underlying five general classes of NCE-MRA methods (inflow effect, flow-dependency on cardiac phase, flow-encoding, spin labeling, and relaxation) are explained. The original techniques of time-of-flight (TOF) and phase contrast MRA (PC-MRA) are briefly introduced. New developments in NCE-MRA, including hybrid of opposite-contrast (HOP-MRA), four dimensional PC-MRA (4D Flow), cardiac-gated 3D fast-spin-echo, flow-sensitive dephasing (FSD), arterial spin labeling (ASL), and balanced steady-state free-precession (bSSFP) are highlighted. The primary applications, advantages, and limitations of established and emerging NCE-MRA techniques are discussed.     

ARRONAX,a high-energy and high-intensity cyclotron for nuclear medicine

PURPOSE: This study was aimed at establishing a list of radionuclides of interest for nuclear medicine that can be produced in a high-intensity and high-energy cyclotron. METHODS: We have considered both therapeutic and positron emission tomography radionuclides that can be produced using a high-energy and a high-intensity cyclotron such as ARRONAX, which will be operating in Nantes (France) by the end of 2008. Novel radionuclides or radionuclides of current limited availability have been selected according to the following criteria: emission of positrons, low-energy beta or alpha particles, stable or short half-life daughters, half-life between 3 h and 10 days or generator-produced, favourable dosimetry, production from stable isotopes with reasonable cross sections. RESULTS: Three radionuclides appear well suited to targeted radionuclide therapy using beta ((67)Cu, (47)Sc) or alpha ((211)At) particles. Positron emitters allowing dosimetry studies prior to radionuclide therapy ((64)Cu, (124)I, (44)Sc), or that can be generator-produced ((82)Rb, (68)Ga) or providing the opportunity of a new imaging modality ((44)Sc) are considered to have a great interest at short term whereas (86)Y, (52)Fe, (55)Co, (76)Br or (89)Zr are considered to have a potential interest at middle term. CONCLUSIONS: Several radionuclides not currently used in routine nuclear medicine or not available in sufficient amount for clinical research have been selected for future production. High-energy, high-intensity cyclotrons are necessary to produce some of the selected radionuclides and make possible future clinical developments in nuclear medicine. Associated with appropriate carriers, these radionuclides will respond to a maximum of unmet clinical needs.