PGD血小板细菌污染检测系统效果的评价

目的评价PGD检测系统用于混合血小板制品细菌污染检测的效果。方法分别将配制后经浓缩血小板稀释为101、103和105CFU/ml的大肠埃希菌和表皮葡萄球菌菌悬液进行PGD检测限的评估;将上述菌株分别接种于浓缩血小板中制成菌液浓度为101、103CFU/ml的模拟细菌污染浓缩血小板,经22℃振荡保存24、72、120 h后分别用PGD法和Bact/ALERT法进行细菌检测,比较2种方法的细菌污染检测限和阳性反应时间。结果 PGD法对大肠埃希菌的检测限为105CFU/ml,表皮葡萄球菌为103CFU/ml;将103CFU/ml的大肠埃希菌和表皮葡萄球菌分别接种到浓缩血小板,24 h后PGD检测均为阴性,72 h后均为阳性,而Bact/ALERT法检测在10 h均呈阳性反应;将105CFU/ml的大肠埃希菌和表皮葡萄球菌接种浓缩血小板4 h后PGD检测均为阳性,Bact/ALERT法在3—6 h内均呈阳性反应。结论 PGD检测系统对血小板细菌污染的检测限为(103—105)CFU/ml,适用于医院输血部门在血小板输血前的快速细菌检测。     

PCR检测血小板细菌的引物设计与筛选

目的设计PCR检测血小板细菌的通用引物,评价其在血小板检测中的应用效果。方法在美国国家生物技术信息中心(NCBI)中找到不同细菌中同一片段基因16Sr DNA序列,对其做多序列比对,确定合适的保守区域;使用Primer 5.0设计3对引物探针,采用荧光定量PCR对不同浓度[(101—107)CFU/m L]的标准菌株扩增,通过分析扩增曲线来判断扩增效果。分别将配制后经血小板稀释为101、102、103、104、105、106、107CFU/m L的菌悬液在22℃震荡培养24 h,以荧光定量PCR检测细菌;筛选出灵敏度和特异性最好的引物作为最终引物。结果血小板常见菌做荧光定量PCR检测[对(101—107)CFU/m L的细菌重复检测3次]后,通过对检测灵敏度和特异性的比较,发现第3号组引物(16S-F3:CAACGCG■AACCTTAC,16S-R3:AACC■CATTTCACAACA)不但能避免背景和非特异物的产生,而且能识别低含量的目标DNA,检测的细菌浓度范围含量为(102—108)CFU/m L。结论细菌通用引物的设计与筛选为血小板细菌的核酸检测方法的建立起到了关键的作用。     

核酸扩增法检测细菌的方法研究及其在浓缩血小板制品细菌检测中的初步应用

目的建立符合自动化检测要求的核酸扩增法检测细菌的方法,并初步应用于手工浓缩血小板制品的细菌检测。方法对细菌DNA提取方法进行自动化改造,使用不同菌株评估改良后的方法的灵敏度和特异性,并将该方法应用于100例手工浓缩血小板的检测。结果对细菌DNA提取方法进行改造,满足了自动化检测的要求,该方法对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌和铜绿假单胞菌的灵敏度分别可达10、150、65、15 CFU/m L。使用灭菌水检测50次,均未发现非特异性检测产物。该方法和细菌培养方法同时能从100例手工浓缩血小板中检出1例细菌阳性标本。结论细菌基因组16S DNA检测方法能快速灵敏地检出血小板制品中常见的污染细菌,应用于手工浓缩血小板检测能获得与细菌培养相同的效果。     

应用实时荧光定量PCR方法检测血小板制品细菌污染

目的应用实时荧光定量PCR方法检测血小板制品中细菌的探讨。方法选取金黄色葡萄球菌及大肠埃希氏杆菌,用改良的Chelex-100法抽提细菌基因组DNA,进行荧光定量PCR检测。并应用过滤法去除反应体系中潜在的细菌及其基因组DNA污染。结果针对16srRNA基因保守序列进行扩增的荧光定量PCR方法具有较高的特异性和灵敏度,与人类淋巴细胞及病毒等的基因组无交叉反应。在金黄色葡萄球菌检测中,应用过滤法后最低含菌量组与阴性对照组Ct值有极显著差异(P<0.001)。该方法对金黄色葡萄球菌的最低检出量为0.3CFUs/PCR,与阴性对照Ct值有显著差异(P<0.01),在大肠埃希氏杆菌中该法可检测出0.1CFUs/PCR,与阴性对照Ct值有显著性差异(P<0.01)。结论改良Chelex-100法抽提细菌基因组及后续的荧光定量PCR分析用于检测血小板制品中的细菌污染,检测实验缩短到3-4h,操作简单,灵敏性高,特异性好,为在临床标本大规模检测中的应用提供理论基础和实验数据。     

16S rDNA实时荧光定量PCR法与全自动培养法在血小板细菌污染检测中的应用比较

目的比较16S rDNA实时荧光定量PCR法与全自动培养法在血小板制品细菌污染检测中的灵敏度和特异性,评价2种方法的应用前景。方法将血小板制品污染中常见的6种细菌用浓缩血小板悬液进行稀释,并选取浓度为102、101、100的菌悬液,分别用实时荧光定量PCR法和全自动培养法进行检测。结果用16S rDNA实时荧光定量PCR法对6株细菌检测,其灵敏度和特异性均为100%,Κ=1.000。用全自动培养仪对6株细菌检测,其特异性均为100%;灵敏度分别为:金黄色葡萄球菌需氧瓶95.5%,Κ=0.886,厌氧瓶90.9%,Κ=0.787;表皮葡萄球菌及大肠杆菌2种培养瓶均为83.3%,Κ=0.667;蜡样芽孢杆菌2种培养瓶均为86.7%,Κ=0.684;铜绿假单胞杆菌需氧瓶度为100%,Κ=1.000,厌氧瓶为44.4%,Κ=0.286;痤疮丙酸杆菌需氧瓶为16.7%,Κ=0.105,厌氧瓶为91.7%,Κ=0.886。结论实时荧光定量PCR法检测血小板制品中的细菌污染,灵敏度高,特异性好,且省时、经济,能应用于临床上血液样本的大规模筛查。     

TaqMan探针法荧光定量PCR检测脑脊液细菌方法的建立及应用

目的 建立TaqMan探针法荧光定量PCR检测方法,用于脑脊液标本细菌的快速检测.方法 针对细菌的16S rRNA基因,设计合成细菌的通用引物和革兰阳性菌、革兰阴性菌分型探针,通过构建质粒和制作脑脊液模拟标本来研究引物和探针的检测特异度和敏感度.结果 两种革兰分型探针只对相应的细菌可以检测到荧光信号,乙肝病毒DNA、白色念珠菌及人基因组DNA检测结果均为阴性,此方法最低可以检测到10个拷贝的质粒DNA以及102CFU/ml的金黄色葡萄球菌和大肠埃希菌.结论 TaqMan探针法荧光定量PCR检测细菌的特异度和敏感度高,检测快速,对脑脊液细菌的早期诊断有重要意义.     

常规保存条件下血小板中污染细菌生长动力学研究

为探讨细菌和真菌在常规保存条件下的浓缩血小板中生长繁殖状况,为血小板细菌污染检测与灭活方法提供依据,在实验室采取血小板中人工污染菌和活菌计数方法进行了试验观察。结果,污染后血小板在常规保存条件下(22±2)℃,最长保存期7d内每日含菌量变化,金黄色葡萄球菌和大肠杆菌均在第2、3d表现出迅猛的增殖高峰,第4d以后增殖趋于平缓。白色念珠菌增殖速度较为平缓,但亦呈持续增殖趋势。结论,细菌与真菌均可在常规保存条件下的血小板中持续生长,保存时间越长,发生输血后并发症的可能性越大。     

建立实时荧光LAMPA法检测肺炎支原体

目的:建立实时荧光环介导等温扩增(LAMP)法检测肺炎支原体。方法:在LAMP体系中添加适量荧光染料SYTO-9,通过实时定量PCR仪监测LAMP反应结果。以肺炎支原体P1基因重组质粒制备一系列浓度标准品,分别使用实时荧光LAMP法和SYBR GreenⅠ染料LAMP法检测,比较2种方法的检出限。肺炎支原体M129标准株菌液以10倍梯度稀释,分别以实时荧光LAMP法和肺炎支原体荧光PCR试剂盒检测,比较2种方法灵敏度。以实时荧光LAMP法检测常见呼吸道感染病原体肺炎链球菌、金黄色葡萄球菌、表皮葡萄球菌、肺炎克雷伯菌、鲍曼不动杆菌、铜绿假单胞菌和大肠埃希菌基因组DNA,评估该方法特异性。采集疑似肺炎支原体感染患儿咽拭子标本,分别以实时荧光LAMP法和荧光PCR法检测,比较2种方法检出率差异。结果:实时荧光LAMP法可以检出P1基因最低限为103 copies/μL,当基因拷贝数大于104 copies/μL时,反应30 min样本组即可出现明显荧光信号。SYBR GreenⅠ染料LAMP法可以检出P1基因最低限为104 copies/μL,反应需1 h才可获得足够产物用于显色。实时荧光LAMP法灵敏度高于实时定量PCR法100倍,且对常见呼吸道病原体DNA无扩增。实时荧光LAMP法和荧光PCR法检测疑似肺炎支原体感染咽拭子标本的阳性率差异无统计学意义(P>0.05)。结论:实时荧光LAMP法可以有效避免因开盖检测造成的气溶胶污染,反应时间短,灵敏度高,适于在基层医院中推广使用。     

建立实时荧光LAMP法检测肺炎支原体

目的建立实时荧光环介导等温扩增(LAMP)法检测肺炎支原体。方法在LAMP体系中添加适量荧光染料SYTO-9,通过实时定量PCR仪监测LAMP反应结果。以肺炎支原体P1基因重组质粒制备一系列浓度标准品,分别使用实时荧光LAMP法和SYBR GreenⅠ染料LAMP法检测,比较2种方法的检出限。肺炎支原体M129标准株菌液以10倍梯度稀释,分别以实时荧光LAMP法和肺炎支原体荧光PCR试剂盒检测,比较2种方法灵敏度。以实时荧光LAMP法检测常见呼吸道感染病原体肺炎链球菌、金黄色葡萄球菌、表皮葡萄球菌、肺炎克雷伯菌、鲍曼不动杆菌、铜绿假单胞菌和大肠埃希菌基因组DNA,评估该方法特异性。采集疑似肺炎支原体感染患儿咽拭子标本,分别以实时荧光LAMP法和荧光PCR法检测,比较2种方法检出率差异。结果实时荧光LAMP法可以检出P1基因最低限为10~3 copies/μL,当基因拷贝数大于10~4 copies/μL时,反应30 min样本组即可出现明显荧光信号。SYBR GreenⅠ染料LAMP法可以检出P1基因最低限为10~4 copies/μL,反应需1 h才可获得足够产物用于显色。实时荧光LAMP法灵敏度高于实时定量PCR法100倍,且对常见呼吸道病原体DNA无扩增。实时荧光LAMP法和荧光PCR法检测疑似肺炎支原体感染咽拭子标本的阳性率差异无统计学意义(P0.05)。结论实时荧光LAMP法可以有效避免因开盖检测造成的气溶胶污染,反应时间短,灵敏度高,适于在基层医院中推广使用。     

保存前白细胞过滤对添加剂红细胞中细菌增殖的影响

目的探讨白细胞过滤对添加剂红细胞中细菌增殖的影响。方法3个单位添加剂红细胞以100 CFU/m l的浓度人为接种金黄色葡萄球菌、大肠埃希氏菌及铜绿假单胞菌,然后等分为二,一份经白细胞过滤,另一份作为对照,置4℃保存14 d,每周取样作细菌培养计数。结果添加剂红细胞经白细胞过滤后,经2 w保存未见有金黄色葡萄球菌与铜绿假单胞菌生长,残留的大肠埃希氏菌有显著增殖,但其增殖数量要明显低于对照组。结论保存前过滤白细胞能有效地减少或消除细菌的增殖,对预防细菌污染所致的输血反应有一定意义。     

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.