放疗增强对转染pAdKDR／CD／TK自杀基因系统的SW480大肠癌细胞的杀伤作用

目的研究γ射线照射对含KDR启动子双自杀基因大肠癌细胞SW480的杀伤协同作用,和自杀基因及前药的放射增敏作用。方法重组腺病毒pAdKDR—TK、pAdKDR-CD和pAdKDR—TK／CD转染SW480细胞,观察7射线对SW480细胞基因转染率的增强作用和对前药GCV、5-FC、GCV＋5-FC杀伤SW480细胞的放射增敏效应,以及前药GCV、5-FC、GCV＋5-FC对γ射线杀伤SW480细胞的协同增效作用。结果转染双自杀基因的大肠癌细胞射线组比对照组转染率有明显升高（P〈O．01）,7射线对转染KDR—TK／CD基因的SW480细胞比未转染基因的对照组SW480细胞具有更强的杀伤作用（P〈0．001）。结论γ射线照射能明显提高双自杀基因的转染效率,强化了基因治疗的“旁观者效应”,自杀基因对γ射线的增敏作用。     

以KDR为启动子的双自杀基因系统诱导结肠癌细胞凋亡的实验研究

目的研究以KDR为启动子的双自杀基因系统CDglyTK诱导结肠癌细胞凋亡的实验研究。方法用联合基因AdKDR-CDglyTK腺病毒转染表达KDR不同的人结肠癌细胞HCT116和LS174T,检测转染效率;RT-PCR检测双自杀基因CDglyTK的表达;用梯度浓度的前药5-FC及GCV处理,MTT法检测双自杀基因系统对HCT116和LS174T的细胞毒性作用;流式细胞术观察细胞凋亡变化;免疫组织化学法检测caspase-3蛋白的表达。结果携带双自杀基因的重组腺病毒载体成功转染结肠癌细胞。RT-PCR结果显示：表达KDR的HCT116细胞能表达目的基因,而不表达KDR的LS174T细胞不表达目的基因。5-FC和GCV对转染腺病毒的HCT116有明显的细胞毒作用而对LS174T细胞不敏感。流式细胞仪结果显示：给予5-FC和GCV后HCT116细胞出现凋亡峰,G0/G1升高、S期下降。Caspase-3表达增强（P〈0.01）。结论 KDR启动子驱动的双自杀基因系统CDglyTK能特异性杀伤结肠癌HCT116细胞,KDR可作为结肠癌基因治疗的靶点,并通过增强caspase-3途径诱导细胞凋亡。     

pAdKDR/CD/TK自杀基因系统对大肠癌SW480细胞体外杀伤作用的实验研究

目的研究腺病毒介导的KDR/CD/TK双自杀基因系统对大肠癌SW480细胞的杀伤作用。方法构建pAdKDR/CD/TK重组腺病毒,采用不同感染复数(MOI)的重组腺病毒感染大肠癌SW480细胞、ECV304细胞及LS174T细胞,再加入不同浓度前药(GCV、5-FC)培养后,以MTT法检测细胞生长抑制率,观察重组腺病毒联合GCV和5-FC对大肠癌SW480细胞、ECV304细胞和LS174T细胞的杀伤作用,了解前药GCV、5-FC、GCV/5-FC对3种细胞的杀伤作用及KDR启动子的靶向杀伤作用。结果 pAdKDR/CD/TK重组腺病毒对3种细胞具有相似的感染率,感染腺病毒的3种细胞中除LS174T细胞外,均检测到目的基因的表达。当转基因细胞的比率为50%时,SW480和ECV304细胞分别有(31.3±5.64)%、(33.5±5.4)%的存活,而LS174T细胞存活率仍为(98.1±0.95)%(P均<0.01)。单用GCV浓度为80μg/ml时,SW480细胞、ECV304细胞、LS174T细胞的生存率分别为(45.6±6.5)%、(45.9±5.4)%、(99.5±4.7)%,单用5-FC浓度为1000μg/ml时,三者生存率分别为(40.4±5.8)%、(45.3±4.7)%、(97.0±6.2)%,联合用药(80μg/ml+1000μg/ml)时,三者生存率分别为(20.5±0.46)%、(25.6±1.33)%、(97.3±3.96)%。联合用药分别与GCV及5-FC单独用药生存率比较,差异均有统计学意义(P均<0.05)。提示单独应用GCV及5-FC对SW480细胞、ECV304细胞有较强的杀伤作用,联合用药效果更佳。结论含KDR启动子的融合基因,具有选择性杀伤作用。前药GCV、5-FC对转染融合基因的大肠癌SW480细胞具有体外抑制作用,且有较强的旁观者效应。     

mdr1启动子驱动的CD-TK双自杀基因载体对耐药K562细胞的体外靶向杀伤作用

目的构建多药耐药基因（mdrl）启动子控制的胸苷激酶一胞嘧啶脱氨酶（CD—TK）双自杀基因真核表达载体，研究其对耐药白血病细胞K562／A02的靶向杀伤作用。方法利用分子克隆技术构建pcDNA3-mdr1P．CD—TK真核表达载体，脂质体介导法转染K562、K562／A02细胞，通过G418筛选获得稳定转染的细胞株。用PCR、RT—PCR鉴定TK、CD基因的稳定转染与表达，加用不同浓度的丙氧鸟苷（GCV）、5-氟胞嘧啶（5-FC）培养4d，用四甲基偶氮唑蓝（MTr）法测定细胞存活率，用流式细胞术检测细胞凋亡率。结果成功构建了mdrl启动子控制的CD-TK双自杀基因真核表达载体，脂质体成功转染细胞后，经G418筛选获得稳定转染细胞株。PCR结果显示，CD、TK基因均稳定存在于K562、K562／A02细胞中，RT—PCR结果显示K562／A02-CD—TK细胞有CD、TK基因特异性条带表达，而K562一CD—TK细胞无特异性条带。加入GCV、5-FC后，与K562-CD—TK细胞相比，K562／A02-CD—TK细胞存活率明显降低（在60μg／，mlGCV和600μg／ml5-FC联合作用后两种细胞存活率分别为85．04％和41．13％）（P〈0．05），凋亡率明显升高（同样浓度下分别为2．93％，10．27％）。结论mdrl启动子驱动的CD—TK双自杀基因系统可以靶向杀伤多药耐药的白血病细胞。     

CDglyTK自杀基因系统治疗小鼠慢性粒细胞白血病皮下移植瘤的研究

为了探讨逆转录病毒介导的CDglyTK自杀基因系统时K562细胞的体内外杀伤作用，将逆转录病毒介导的CDglyTK自杀基因转染入K562细胞，体外实验用MTT法观察5-氟胞嘧彰丙氧鸟苷（5-fluorocytosine／ganciclovir，5-FC／GCV）时K562／CDglyTK细胞的生长抑制率。体内实验时将K562／CDglyTK细胞和K562细胞接种于裸鼠皮下，使用GCV和5-FC后，观察裸鼠肿瘤体积的变化及裸鼠的生存率。体外实验表明，GCV联合5-FC时K562／CDglyTK细胞具有明显的杀伤作用；体内实验结果显示，皮下注射K562细胞和K562／CDglyTK细胞后小鼠成瘤率无明显区别；使用5-FC／GCV可明显抑制裸鼠体内的肿瘤形成；经5-FC／GCV治疗后K562／CDglyTK组的肿瘤体积较对照组明显缩小，裸鼠生存率也较时照组明显提高。结论：双自杀基因在体内外对K562细胞均有杀伤作用。     

pAdKDR/CD/TK双自杀基因系统对肝癌细胞的杀伤作用的试验研究

目的探讨含KDR启动子的双自杀基因CD/TK对肝癌HepG2细胞的杀伤作用。方法观察不同前药对HepG2细胞、血管内皮细胞ECV304和LST174细胞的杀伤作用,评估KDR启动子的靶向杀伤作用。观察不同前药对转染不同自杀基因的HepG2细胞的杀伤作用,及旁观者效应。结果转染腺病毒的HepG2细胞及血管内皮ECV304细胞对前药具有较高的敏感性,而感染腺病毒的LST174细胞对前药不敏感(P0.05)。当转染细胞混合比例为50%时,应用前药后,转染CD/TK,CD,TK的HepG2细胞生存率分别为11.8±1.2%、41.3±3.7%、43.1±2.3%(P0.05)。结论含KDR启动子的双自杀基因CD/TK对肝癌HepG2细胞具有高度靶向杀伤作用;联合用药对转染双自杀基因的肝癌HepG2细胞具有协调增强杀伤作用。     

双自杀基因慢病毒转移载体系统的构建及其对K562细胞的杀伤作用

为了探讨双自杀基因慢病毒转移载体系统对K562细胞的杀伤作用,采用分子生物学方法构建了含大肠杆菌胞嘧啶脱氨酶(E.coli CD)和单纯疱疹病毒胸苷激酶(HSV-TK)的双自杀基因慢病毒转移载体,将慢病毒基因转移系统中的3种成分质粒(目的基因转移载体、包装结构及包膜结构质粒)用脂质体分为2组(实验组、对照组)共转染入病毒包装细胞293T,在荧光显微镜下观察转染效果,在透射电镜下观察上清中的病毒颗粒.大量收集病毒上清,浓缩后感染K562细胞,荧光显微镜下观察感染效果,RT-PCR鉴定目的基因在K562细胞中的整合转录.给予前体药物5-氟胞嘧啶(5-FC)和(或)无环鸟苷(GCV)后,用MTT法测定体外杀伤效应,扫描电镜下观察使用前体药物后K562细胞的变化.结果表明成功构建了双自杀基因慢病毒转移载体,脂质体法可有效将上述慢病毒表达质粒转入293T细胞.荧光显微镜下观察到对照组大量绿色荧光蛋白(green fluorescenceprotein,GFP)表达.透射电镜下观察到大量浓缩后病毒颗粒.荧光显微镜下观察到此基因转移载体系统对293T细胞及K562细胞的感染率均很高,单独使用GCV或5-FC对转染自杀基因的K562细胞的生长抑制率(growth inhibition ration,GIR)分别为48.73%、50.16%,与未转染K562细胞比较明显升高,有显著性差异(P＜0.01),联合使用5-FC和GCV时K562细胞的GIR为87.69%,比单独使用5-FC或GCV时明显升高,有显著性差异(P＜0.01).结论双自杀基因慢病毒基因转移载体系统可将双自杀基因高效转移至K562细胞,是一种有效的基因转移载体系统.     

HSV-TK和IL-12联合基因对宫颈癌的杀伤作用

目的观察单纯疱疹病毒胸苷激酶(HSV-TK)丙氧鸟苷(GCV)自杀基因系统联合IL-12基因对人宫颈癌hela细胞系体外杀伤作用。方法采用脂质体转染法将HSV-TK及IL-12联合基因转染hela细胞,并将其用于体外实验,观察GCV对转染联合基因的Hela的杀伤作用及旁观者效应等。结果加入GCV后体外培养联合基因转染的Hela细胞,24 h后细胞明显发生形态上改变,正常对照组细胞生长旺盛;随着GCV剂量的加大,转染联合基因的Hela细胞的存活率呈逐渐下降的趋势,GCV对转染细胞的杀伤作用较对正常细胞的杀伤作用明显增强。并观察到自杀基因系统具有明显的旁观者效应。结论脂质体可介导HSV-TK及IL-12联合基因转入人宫颈癌hela细胞并获得稳定表达,GCV对HSV-TK及IL-12联合基因转染的hela细胞具有明显的杀伤作用。     

自杀基因抑制K562细胞成瘤的动物实验研究

目的探讨自杀基因胞嘧啶脱氨酶（CD）和胸苷激酶（TK）在小鼠体内对K562细胞的抑制作用。方法将在慢病毒介导下已转染CDglyTK的K562细胞种植于裸鼠皮下，观察其成瘤情况和对前体药物[环氧鸟苷（GCV）、5-氟胞嘧啶（5-FC）3的敏感性。结果种植K562细胞和K562／CDglyTK细胞的裸鼠分别在（7．0土1．2）和（7．1土0．9）d后长出肉眼可见的瘤块。两组裸鼠生存期分别是（52．2土5．3）和（54．2±3．7）d，差异无统计学意义（P〉O．05）；接种K562／CDglyTK细胞的小鼠经GCV和5-FC处理后，其裸鼠分别在（26．9土I．7）、（25．7土I．9）d后肉眼可见肿瘤生长，对照组接种K562细胞后（6．9±I．7）d生长出肉眼可见肿瘤，两者差异有统计学意义（P〈0．01）。结论自杀基因在体内对K562细胞有明显的抑制作用，能增强前体药物GCV和5-FC对肿瘤细胞的药物作用。     

腺病毒介导的CDglyTK基因影响胃癌细胞形态学及生长特性的效应

目的：观察已转染双自杀基因的胃癌细胞和未转染双自杀基因的胃癌细胞在形态学及生长特性方面的差异性。 方法：实验于2005—03／2006—03在南方医科大学肿瘤研究所完成。质粒pAdEasy-KDR-CDglyTK为南方医科大学珠江医院普外科保存。用感染复数为100时，将启动子融合基因腺病毒（Ad-KDR—CDglyTK）体外感染SCG7901细胞株。通过倒置荧光相差显微镜、光镜、透射电镜等技术观察转染基因的胃癌细胞的形态学变化。通过流式细胞仪检测细胞周期的变化．同时用四甲基偶氮唑盐方法进行生长曲线的测定。 结果：①腺病毒介导的KDR启动子驱动的双自杀基因对胃癌细胞体外培养的形态无明显影响。②已转基因的SCG7901细胞和未转基因的SCG7901细胞处于G1期，比率分别为（49．00&;#177;0．58）％，（51．02&;#177;0．91）％（t=1．862，P=1．12），处于S期比率分别为（16．20&;#177;0．36）％，（14．00&;#177;0．99）％（t=2．07，P=0．84），处于G2期比率分别为（34．60&;#177;0．96）％，（34．31&;#177;0.86）％（t=0．223，P=0．831）。（3）已转基因SCG7901细胞和未转基因SCG7901细胞具有类似的生长状态（F=0．042,P=0．838〉0．05）。 结论：已转染KDR启动子融合基因的胃癌细胞和未转染的胃癌细胞在形态及生长特性方面无显著性差异。     

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.