SV2A基因真核表达质粒构建及其在HEK293T细胞中的表达

目的构建鼠突触囊泡蛋白2A(SV2A)基因的真核表达质粒,并瞬时转染至人胚肾细胞(HEK293T)中,对其表达进行鉴定。方法以APP/PS1双转基因小鼠海马组织的cDNA为模板,扩增得到长2239 bp的SV2A基因编码序列,将此序列插入到真核表达载体p3×Flag-CMV-10多克隆位点区域中,得到真核表达质粒p3×Flag-CMV-10-SV2A,转化后挑取单克隆菌落经双酶切鉴定后送公司测序,将构建成功的重组质粒转染至HEK293T细胞中,利用蛋白质印迹法(Western blot)检测SV2A基因的表达情况。结果成功构建p3×Flag-CMV-10-SV2A重组质粒,并在转染至HEK293T细胞后,验证了相应蛋白表达。结论利用分子克隆技术成功构建了p3×Flag-CMV-10-SV2A真核表达质粒并在HEK293T细胞中正确表达,为后续实验奠定了基础。     

重组分泌型人类免疫缺陷病毒Tat蛋白在真核细胞中的表达及活性检测

目的 构建人类免疫缺陷病毒病毒 tat基因的重组分泌型真核表达载体并在真核细胞中表达,检测表达的重组蛋白活性。方法 聚合酶链反应（PCR）从重组质粒pcDNA3．1（＋）/Tat中扩增tat基因,利用 HindⅢ和Bam HⅠ酶切位点分别将tat基因正向、反向插入分泌型载体pSecT ag ,获得正向插入克隆（pSecT at ）和反向插入克隆（pSecTat-AS）,经双酶切鉴定连接成功后,利用测序鉴定其序列和插入方向。将构建的重组质粒转染293细胞,利用Western blot法检测Tat蛋白的表达。进而将重组质粒与LTR-CAT报告质粒共转染293细胞和BCBL-1细胞,CAT-酶联免疫吸附试验（ELISA）检测其细胞内CAT表达,从而检测Tat蛋白的活性。最后将转染重组质粒的293细胞与转染LTR-CAT报告质粒的BCBL-1细胞用Transwell培养系统共培养,CAT-ELISA检测分泌型Tat蛋白的旁分泌调控活性。结果 PCR扩增产物在10 g/L琼脂糖凝胶上约300 bp位置出现条带,与预期的324 bp大小相符;经HindⅢ和BamHⅠ分别酶切鉴定,获得2个正向克隆;正向克隆经测序,克隆的 tat基因序列与Gen-Bank中登记的HIV-1 tat基因100％同源。正向克隆质粒转染293细胞后,Western blot法检测观察到约19×10^3蛋白条带。正向克隆质粒与LTR-CAT报告质粒共转染293细胞和BCBL-1细胞CAT 表达量高于反向克隆质粒转染细胞（P＜0．05）。与反向克隆对照相比,与正向克隆转染的293细胞共培养的BCBL-1细胞CAT表达量更高（P＜0．05）。结论 成功构建 HIV-1 tat基因基因分泌型真核表达载体,该载体不但可在真核细胞内表达具有调控活性的T at蛋白,表达的Tat蛋白还可分泌至细胞外并具有调控活性。     

人上皮细胞黏附分子的真核表达及鉴定

目的构建人上皮细胞黏附分子(EpCAM)全基因的真核表达质粒,研究其在HepG2细胞中的表达。方法将EpCAM基因克隆入真核表达载体pcDNA3.1(+),构建真核表达质粒pcDNA3.1(+)-EpCAM,转染人肝癌HepG2细胞。通过免疫荧光、Western Blotting及流式细胞检测对转染后细胞内EpCAM蛋白的表达进行鉴定。结果双酶切鉴定结果表明重组质粒构建成功。免疫荧光、Western Blotting及流式细胞检测结果一致表明,转染后EpCAM基因在HepG2细胞中表达成功。结论成功构建了人EpCAM的真核表达载体,并在HepG2细胞中表达,为研究高表达人EpCAM的肝癌细胞的功能打下基础。     

小鼠CXCR4基因慢病毒载体构建与真核表达

本研究旨在克隆小鼠CXC型趋化因子受体4（CXCR4）基因,构建携带增强型绿色荧光蛋白（EGFP）的CXCR4重组慢病毒载体并在真核细胞中表达。采用逆转录-聚合酶链式反应（RT-PCR）以C57BL／6小鼠骨髓细胞为模板克隆全长型CXCR4基因,连接至克隆载体pCR-Blunt,经限制性内切酶酶切后亚克隆至慢病毒转移载体,构建携带EGFP及CXCR4双顺反子结构的自身失活型重组慢病毒表达质粒;同时构建LV-IRES-EGFP作为对照质粒;通过脂质体转染法与包装质粒及包膜蛋白质粒共转染包装细胞293FT,超速离心浓缩病毒颗粒后转染293FT细胞,采用荧光显微镜和流式细胞术（FCM）检测EGFP的表达,Western blot鉴定CXCR4蛋白表达。结果表明,成功克隆小鼠CXCR4基因,构建重组慢病毒转移质粒LV-IRES-EGFP-CXCR4及对照质粒LV-IRES-EGFP,三质粒系统共转染293FT细胞后获得病毒滴度可达到10^8TU／ml。以重组慢病毒颗粒感染293Fr细胞后第3天,在荧光显微镜下观察到较强绿色荧光表达,FCM检测显示感染效率可达95％,FCM及Western blot结果显示感染后293Fr细胞表达CXCR4蛋白。结论：成功构建自身失活型慢病毒载体LV-IRES-EGFP-CXCR4,并在真核细胞中获得表达。     

截短型小鼠成纤维细胞生长因子受体-1基因慢病毒载体构建及在真核细胞中的表达

本研究旨在克隆小鼠成纤维细胞生长因子受体1(fibroblast growth factor receptor 1,fgfr1)基因,构建携带增强型绿色荧光蛋白(EGFP)的截短型fgfr1(△fgfr1)重组慢病毒载体并在真核细胞中表达。采用逆转录-聚合酶链反应(RT-PCR)以BALB/c胎鼠脑组织为模板克隆全长型fgfr1基因,连接至克隆载体pCR-Blunt,通过反向PCR技术删除胞内磷酸化区域获得△fgfr1,限制性内切酶酶切后亚克隆至慢病毒转移质粒,构建携带EGFP及△fgfr1双顺反子自身失活型重组慢病毒表达质粒,通过脂质体转染法与包装质粒及包膜蛋白质粒共转染包装细胞293FT,超速离心浓缩病毒颗粒后转染293FT细胞,用荧光显微镜及流式细胞术(FCM)检测EGFP的表达,免疫印迹法(Western blot)鉴定截短型FGFR1蛋白表达。结果表明,成功克隆小鼠fgfr1基因,构建重组慢病毒转移载体LV-IRES-EGFP-△fgfr1及对照载体LV-IRES-EGFP,三质粒系统共转染293FT细胞后获得病毒滴度达到108 TU/ml。以重组病毒载体转染293FT细胞后第4天在荧光显微镜下观察到较强绿色荧光表达,FCM检测转染效率可达95%,Western blot检测显示,转染后293FT细胞表达截短型FGFR1蛋白。结论:成功构建了自身失活型慢病毒载体LV-IRES-EGFP-△fgfr1,并在真核细胞中获得表达。     

小鼠Cdc14A基因真核表达载体的构建

目的构建小鼠pcDNA3.1-MYC-细胞分裂周期14A(Cdc14A)真核表达载体,并观察和验证其在真核细胞中的表达。方法将化学合成的目的基因Cdc14A定向克隆至真核表达载体pcDNA3.1(+)中,经酶切和测序鉴定正确后,采用脂质体法转染HEK293细胞,通过Western blot检测细胞内Cdc14A的表达,并检测Cdc14A基因序列。结果 pcDNA3.1-MYC-Cdc14A真核表达载体构建成功,将其转染HEK293细胞48h,提取细胞蛋白,采用Western blot检测到细胞内Cdc14A的表达,并且测序结果与预期结果一致。结论成功构建了真核表达载体pcDNA3.1-MYC-Cdc14A,为研究Cdc14A在小鼠一细胞期受精卵G2/M期转换中的作用奠定了基础。     

大鼠组织因子基因克隆及其在C6细胞系中的表达

目的:克隆大鼠组织因子(tissue factor,TF)基因,构建真核表达载体pEGFP-N1-TF,转染C6大鼠神经胶质瘤细胞并检测转染细胞内TF表达水平.方法:采用RT-PCR法从Wistar大鼠肺组织中扩增TF基因,克隆到真核表达载体pEGFP-N1上.通过测序鉴定重组质粒中插入TF的完整性和可靠性.应用脂质体法将鉴定正确的重组质粒转入C6细胞中,荧光显微镜下观察EGFP报告基因的表达强度和转染效率,并对转染细胞的TF-eGFP融合蛋白进行Western blot检测.结果:成功构建pEGFP-N1-TF真核表达载体,转染C6细胞24 h后,在荧光显微镜下可以观测到荧光,并通过Western blot技术检测到TF-eGFP融合蛋白的表达.结论:重组真核表达载体pEGFP-N1-TF构建成功,转染C6细胞后获得了良好的瞬时表达.     

Fcγ-Der f2载体构建及融合蛋白表达

目的构建人IgG Fcγ1片段Fcγ与粉尘螨Ⅱ类抗原Der f2嵌合基因真核表达载体pDisplay-Fcγ-Der f2,并转染入HEK293T细胞系瞬时表达,获得Fcγ-Der f2融合蛋白。方法以pMD19-T-Der f2载体为模板,设计引物并加入linker序列,经PCR扩增得到linker-Der f2 DNA片段。经限制性内切酶酶切后,先后将人Fcγ及linker-Der f2基因片段接入pDisplay真核表达载体。用Attractene转染试剂将其转染至HEK293T细胞使之表达融合蛋白。免疫荧光检测转染后γ2 h的HEK293T细胞并裂解细胞进行Western Blot检测。结果 pDisplay-Fcγ-Der f2质粒经双酶切鉴定及DNA测序鉴定证实序列完全正确,真核表达载体构建成功。免疫荧光鉴定转染细胞可见明显红色荧光。Western Blot检测证明融合蛋白相对分子质量为40×10~3,与理论预期值相符合,并证明了Fcγ与Der f2双功能特性。结论构建的融合蛋白Fcγ-Der f2符合目的要求。     

携带小鼠RORγt基因慢病毒载体的构建及其在293FT细胞中的表达

本研究构建携带小鼠ROFγt和glp基因的重组慢病毒载体,检测RORγt蛋白在293FT细胞中的表达。用RT-PCR扩增小鼠RORγt基因,将其克隆至PCR2.1T载体,酶切制备RORγtDNA片段,插入MigR1质粒后将RORγt-IRES-GFP定向连入慢病毒转移质粒pTK208,生成pXZ9-RORγt。用脂质体介导三质粒共转染法转染293FT细胞,荧光显微镜下观察GFP表达情况,以Western blot鉴定RORγt的表达。结果表明,RT-PCR扩增出RORγt基因并克隆入PCR2.1T载体;经亚克隆构建了慢病毒转移质粒XZ9-RORγt。质粒经脂质体转染293FT细胞获慢病毒颗粒,慢病毒颗粒体外高效感染293FT细胞,感染后Western blot检测到RORγt蛋白表达。结论：成功构建慢病毒载体pXZ9-RORγt,并在293细胞内获得表达。     

SEA和喉癌MAGE-A3基因重组真核共表达载体的构建和鉴定

目的构建超抗原SEA和喉癌来源的MAGE-A3基因共表达的真核表达载体,检测、鉴定其在293T细胞中的表达。方法分别用RT-PCR方法及人工化学合成法获得MAGE-A3和SEA基因片段,然后依次将MAGE-A3和SEA基因克隆至含内部核糖体进入位点的真核表达载体IRES序列的上、下游,构建成重组质粒pMAGEA3-IRES-SEA。经脂质体转染至293T细胞以后,用荧光定量PCR、蛋白免疫印迹分别鉴定SEA、MAGE-A3基因的表达。结果限制性内切酶酶切分析证实MAGE-A3基因和SEA基因均正确地克隆在pMAGEA3-IRES-SEA中,基因测序结果与GenBank公布的MAGE-A3、SEA序列完全一致,实现了双基因的正确重组。重组质粒转染293T细胞后能检测到MAGE-A3、SEA基因的高水平表达。结论成功地构建了pMAGEA3-IRES-SEA真核表达质粒,并能在293T细胞中有效表达MAGE-A3和SEA蛋白,由此奠定了其作为抗喉癌DNA疫苗应用的基础。     

Determination of creatine kinase isoenzyme MB activity in serum using immunological inhibition of creatine kinase M subunit activity. Activity kinetics and diagnostic significance in myocardial infarction.

This is a new method for the determination of creatine kinase isoenzyme MB activity in serum. The method uses direct activity measurement of creatine kinase B subunit activity after blocking of CK-M subunit activity by inhibiting antibodies. The test takes no longer than 15 min. The method yields an intra-serial C.V. of 2.0-12.9%, and a C.V. from day to day of 5.5%. The detection limit is 3.4 U/l creatine kinase MB. In the 95 cases with proven myocardial infarction several types of creatine kinase MB activity kinetics could be determined. The percentage of creatine kinase MB of peak CK-total is 6-25%, with a mean of 11.1%. The amount of creatine kinase MB with respect to total CK activity after reinfarction is higher than the amount after initial infarction.     

Dissociable correlates of two classes of retrieval processing in prefrontal cortex

Although substantial evidence suggests that the prefrontal cortex (PFC) implements processes that are critical for accurate episodic memory judgments, the specific roles of different PFC subregions remain unclear. Here, we used event-related functional magnetic resonance imaging to distinguish between prefrontal activity related to operations that (1) influence processing of retrieval cues based on current task demands, or (2) are involved in monitoring the outputs of retrieval. Fourteen participants studied auditory words spoken by a male or female speaker and completed memory tests in which the stimuli were unstudied foil words and studied words spoken by either the same speaker at study, or the alternate speaker. On "general" test trials, participants were to determine whether each word was studied, regardless of the voice of the speaker, whereas on "specific" test trials, participants were to additionally distinguish between studied words that were spoken in the same voice or a different voice at study. Thus, on specific test trials, participants were explicitly required to attend to voice information in order to evaluate each test item. Anterior (right BA 10), dorsolateral prefrontal (right BA 46), and inferior frontal (bilateral BA 47/12) regions were more active during specific than during general trials. Activation in anterior and dorsolateral PFC was enhanced during specific test trials even in response to unstudied items, suggesting that activation in these regions was related to the differential processing of retrieval cues in the two tasks. In contrast, differences between specific and general test trials in inferior frontal regions (bilateral BA 47/12) were seen only for studied items, suggesting a role for these regions in post-retrieval monitoring processes. Results from this study are consistent with the idea that different PFC subregions implement distinct, but complementary processes that collectively support accurate episodic memory judgments.     

俯卧位通气对高海拔地区肺复张治疗无效急性呼吸窘迫综合征患者氧合的影响

目的 探讨俯卧位通气对高海拔地区肺复张术(RM)治疗无效急性呼吸窘迫综合征(ARDS)患者的治疗作用.方法 从海拔2260m的地区医院筛选RM治疗无效的41例ARDS患者[平均氧合指数( PaO2/FiO2)较RM前升高＜20％视为RM无效],依不同病因分为肺内源性ARDS组(ARDSp组)和肺外源性ARDS组(ARDSexp组),每组再按信封法随机分为俯卧位组和仰卧位组,即ARDSp俯卧位组(11例)、ARDSp仰卧位组(9例)、ARDSexp俯卧位组(10例)、ARDSexp仰卧位组(11例).在通气前及通气1、2、3、4h监测动脉血氧分压( PaO2)、PaO2/FiO2、静态顺应性(Cst)、气道阻力(Raw)的变化.结果 通气lh时,ARDSexp俯卧位组PaO2/FiO2( mm Hg,l mm Hg=0.133 kPa)即较通气前显著升高(157.4±40.6比129.3±48.7,P＜0.05),并随通气时间延长呈持续增高趋势,4h达峰值(219.1 ±41.1);且ARDSexp俯卧位组通气3h内PaO2/FiO2较其他3组显著增高,另3组间则差异无统计学意义.ARDSp俯卧位组、ARDSexp俯卧位组通气4h时PaO2/FiO2均较相应仰卧位组显著增高(208.8±39.7比127.4±47.1,219.1±41.1比124.9±50.8,均P＜0.05).4组通气前后Cst无显著改变,各组间差异也无统计学意义.ARDSp俯卧位组通气4h时Raw(cmH2O·L-1·s-1)较通气前显著降低(6.8±1.7比10.7±1.8,P＜0.05),且明显低于其他3组;其他3组各时间点Raw组内及组间比较差异均无统计学意义.结论 俯卧位通气作为ARDS机械通气重要策略之一,可以改善RM无效高原ARDS患者的氧合,为抢救患者赢得宝贵的时间.     

Digital imaging among medical facilities

The Department of Veterans Affairs (VA) in the USA operates a network of 172 medical centres which all utilize a hospital information system (HIS) which has been developed and is currently maintained by the VA. During the past several years, an image management and communication module has been developed, installed and clinically utilized at the Washington DC and Maryland VA Medical Centres. This image management and communication system, referred to as the decentralized hospital computer program (DHCP) imaging system, is fully integrated with a commercial picture archiving and communication system (PACS). The system is utilized to capture, archive, and display all images generated within the hospital including radiology, nuclear medicine, pathology, endoscopy, bronchoscopy, and dermatology, intraoperative photographs, ECG data, and a limited number of paper documents. The ultimate goal of the project is to have all patient text and image data available at any clinical workstation to any authorized user anywhere within the network of medical centres. Clinical requirements for an imaging workstation include ease of use, rapid and reliable access to the complete set of patient information, and images which are of acceptable quality to meet the requirements of the user and the subspecialty. Patient confidentiality and data security must be safeguarded at all times. Integration of the images with the remainder of the patient's database was found to be critical to the success of the project. The experience at the Washington and Maryland facilities suggests that an imaging system that is successfully integrated with a hospital information system can provide substantial clinical and economic benefits both within and among medical centres. Clinical acceptance and utilization of the system has been excellent, particularly in diagnostic radiology where DHCP Imaging has been interfaced to a commercial PAC system. Based upon this initial experience, the VA has begun to deploy the system throughout its large network of medical centres.     

Myocardial elastography at both high temporal and spatial resolution for the detection of infarcts

Myocardial elastography is a novel method for noninvasively assessing regional myocardial function, with the advantages of high spatial and temporal resolution and high signal-to-noise ratio (SNR). In this paper, in-vivo experiments were performed in anesthetized normal and infarcted mice (one day after left anterior descending coronary artery [LAD] ligation) using a high-resolution (30 MHz) ultrasound system (Vevo 770, VisualSonics Inc., Toronto, ON, Canada). Radiofrequency (RF) signals of the left ventricle (LV) in longitudinal (long-axis) view and the associated electrocardiogram (ECG) were simultaneously acquired. Using a retrospective ECG gating technique, 2-D full field-of-view RF frames were acquired at an extremely high frame rate (8 kHz) that resulted in high-quality incremental displacement and strain estimation of the myocardium. The incremental results were further accumulated to obtain the cumulative displacements and strains. Two-dimensional and M-mode displacement images and strain images (elastograms), as well as displacement and strain profiles as a function of time, were compared between normal and infarcted mice. Incremental results clearly depicted cardiac events including LV contraction, LV relaxation and isovolumetric phases in both normal and infarcted mice, and also evidently indicated reduced motion and deformation in the infarcted myocardium. The elastograms indicated that the infarcted regions underwent thinning during systole rather than thickening, as in the normal case. The cumulative elastograms were found to have higher elastographic SNR (SNR(e)) than the incremental elastograms (e.g., 10.6 vs. 4.7 in a normal myocardium, and 6.0 vs. 2.4 in an infarcted myocardium). Finally, preliminary statistical results from nine normal (m = 9) and seven infarcted (n = 7) mice indicated the capability of the cumulative strain in differentiating infracted from normal myocardia. In conclusion, myocardial elastography could provide regional strain information at simultaneously high temporal (>/=0.125 ms) and spatial ( approximately 55 microm) resolution as well as high precision ( approximately 0.05 microm displacement). This technique was thus capable of accurately characterizing normal myocardial function throughout an entire cardiac cycle, at the same high resolution, and detecting and localizing myocardial infarction in vivo.     

Clinical Pharmacokinetics of Morphine

Morphine, the most widely used mu-opioid analgesic for acute and chronic pain, is the standard against which new analgesics are measured. A thorough understanding of the pharmacokinetics of morphine is required in order to safely and effectively use this analgesic in a wide variety of patients with different levels of organ function. A MEDLINE search was conducted to identify literature published between 1966 and January 2002 relevant to the pharmacokinetics of morphine. These publications were reviewed and the literature summarized regarding unique and clinically important elements of morphine disposition relative to its parenteral administration (including intravenous, intramuscular, subcutaneous, epidural and intrathecal administration), absorption profile (immediate release, controlled release, and sublingual/buccal, and rectal administration), distribution, and its metabolism/ excretion. Special populations, including infants, elderly, and those with renal/liver failure, have a unique morphine pharmacokinetic profile that must be taken into account in order to maximize analgesic efficacy and reduce the risk of adverse events.