实时荧光定量RT-PCR法定量检测手足口病病原体的探讨

目的了解北京市门头沟区手足口病患儿感染病毒的型别,探索用荧光定量RT—PCR法对手足口病患者咽拭子标本中肠道病毒71型（EV71）、柯萨奇病毒A16（CoxA16）型病毒载量进行定量检测的可行性。方法采用实时荧光RT—PCR体外扩增法对81例手足口病患儿咽拭子标本提取的RNA进行检测。结果28例手足口病患者体内CoxA16病毒载量〉10^3 copies·ml-1。实时荧光定量RT—PCR法构建的标准曲线显示,样本阈值环数（Ct）值与病毒拷贝数的对数（10g10）之间的相关系数为0．9998,相关性良好。4例手足口病患者咽拭子标本中EV71型病毒载量〉10^3 copies·ml-1。实时荧光定量RT-PCR法标准曲线显示,Ct值与病毒拷贝数的对数之间的相关系数为0．9996,相关性较好。结论门头沟区手足口病病原谱以CoxA16型为主,34．6％的手足口病患儿CoxA16型病毒载量〉10^3 copies·ml-1,4．9％的患儿EV71型〉10^3 copies·ml-1。实时荧光定量RT-PCR法对咽拭子标本中CoxA16、EV71核酸定量检测比较简便快速、结果直观、稳定性强,为进一步探讨患者体内病毒载量与临床症状的关系打下了良好的基础。     

实时定量PCR检测马传染性贫血病毒载量方法的建立和应用

目的建立实时定量PCR检测血浆病毒载量的方法，对马传染性贫血病毒（equine infectious anemia virus，EIAV）强毒株攻毒马和疫苗免疫攻毒马血浆中病毒载量进行了跟踪检测，探讨病毒载量和临床疾病状态的相关性。方法以EIAV强毒株LN40序列为标准，在gag保守区设计1对引物和Taqman探针，用于实时定量PCR扩增，用含扩增目的基因的体外转录RNA作标准品，获得标准曲线，对扩增样品进行准确定量。强毒株LN40直接攻毒，或者疫苗株DLV免疫马6个月后用强毒株LN40进行攻毒，跟踪检测攻毒马及免疫攻毒马血浆中EIAV载量情况。结果反应在10^1～10^9copies／ml之间具有良好的线性关系，反应的检出下限为10copies／ml。强毒攻毒马出现发热并最终死亡，发热期间马血浆中EIAV载量与体温呈正相关，载量最高达10^7copies／ml。免疫攻毒马未出现发热，其血浆EIAV载量的总体水平低于强毒攻毒马，攻毒后3个月低至10copies／ml以下。结论成功建立了实时定量PCR检测血浆EIAV载量的方法，并证实了用实时荧光定量PER检测EIAV病毒载量的方法来监测动物感染状态具有可行性，为EIAV致病机制研究和弱毒疫苗免疫保护机制的研究提供良好的技术平台。     

阿瓦朗病毒和休斯病毒实时荧光RT-PCR检测方法研究

目的建立可以检测阿瓦朗病毒(Avalon virus,AVAV)和休斯病毒(Hughes virus,HUGV)两种内罗病毒的实时荧光定量RT-PCR检测方法,并进行初步的评价。方法收集、整理、比对、分析在公共数据库发布的两种病毒基因组核苷酸序列,确定检测靶标,设计特异性引物、探针,优化检测程序,建立实时荧光定量RT-PCR检测方法。利用体外转录技术制备的模拟样本、其他病毒感染标本、病毒株和正常人血标本比较评价所建方法的检测限、特异性、重复性特征。结果所建实时荧光定量RT-PCR检测方法可有效扩增检测AVAV和HUGA靶标RNA,检测限分别约为20拷贝/μl和70拷贝/μl,检测科萨努尔森林病毒、乙型流感病毒BV和BY型、甲型流感病毒H3N2、黄热病毒、乙型脑炎病毒、克里米亚-刚果出血热病毒、发热伴血小板减少综合征、内罗毕羊病毒和塔西那病毒样本无非特异性扩增,两种内罗病毒相互间无交叉反应,重复性比较分析显示变异系数小于2%。结论本研究建立的检测AVAV和HUGV的实时荧光定量RT-PCR方法,可用于临床样本检测和媒介生物、宿主动物标本筛查,便于病原的快速识别和疾病诊断。     

实时定量RT-PCR的原理及方法

实时定量RT-PCR广泛应用于定量检测mRAN表达水平,为基础研究、分子药物学和生物技术研究提供了一种有力的方法。该法具有易操作、高通量、敏感性高和特异性强的特点,随着新酶、新探针和新仪器的发展而得到快速的发展。本文将对实时定量RT-PCR的定量原理、仪器应用、探针种类的研究进展以及细胞因子mRNA表达水平检测上的应用作一综述。     

盖塔病毒TaqMan RT-qPCR检测方法的建立与评价

目的:建立一种灵敏且特异的实时荧光定量RT-PCR方法,用于快速检测盖塔病毒(getah virus, GETV)。方法:从GenBank数据库下载GETV基因序列,使用Clustal X完成序列比对,针对高保守区段设计特异性引物和探针;以GETV核酸为标准品建立标准曲线,分别对检测反应的灵敏度、特异性和稳定性进行评价...     

发热伴血小板减少综合征布尼亚病毒实时荧光RT-PCR检测方法的建立

目的 建立新型发热伴血小板减少综合征布尼亚病毒的TaqMan探针实时荧光RTPCR检测方法并进行评估,为发热伴血小板减少综合征监测中新型布尼亚病毒感染的排查提供实验室检测依据.方法 利用新型布尼亚病毒S片段基因的特异性序列设计引物和探针,探针5'端标记FAM,3'端标记TAMRA,优化反应体系与反应条件,并对不同浓度含...     

SFTS病毒、登革病毒、汉滩病毒快速荧光定量RT-PCR检测方法的建立及评价

目的:建立针对发热伴血小板减少综合征病毒(severe fever with thrombocytopenia syndrome virus,SFTSV)、登革病毒(dengue virus, DENV)、汉滩病毒(hantaan virus,HTNV)三种常见病毒性出血热病毒的现场应急快速检测方法。方法:基于传统的T...     

实时荧光定量RT-PCR检测胃癌患者外周血hTERT mRNA表达水平

目的:检测胃癌患者外周血中端粒酶催化亚基hTRT mRNA的表达水平,探讨其作为胃癌早诊标志物的可行性.方法:应用实时荧光定量RT-PCR技术检测108例原发性胃癌、100例良性胃溃疡和120例健康献血员血清hTRT mRNA表达水平.结果:胃癌组hTRT mRNA表达水平(13.48±0.83 copies/ml)显...     

CCR5 mRNA的实时RT-PCR定量检测

CCR5是位于人细胞表面与β 趋化因子MIP 1α、MIP 1β、RANTES结合的受体 ,属于七跨膜区受体超家族的G蛋白偶联受体[1] 。它不仅在HIV的感染过程中作为HIV的辅助受体 ,介导HIV进入宿主细胞 ,而且趋化因子作为功能性的小蛋白分子 ,与淋巴细胞的体内迁移和归巢、造血细胞的生成、胚胎的正常发育、炎症性疾病、肿瘤的生长等功能密切相关[2 ] 。因此精确检测CCR5的表达 ,不仅对临床医学而且对基础医学研究都具有重要意义。通常采用流式细胞法检测CCR5的表达 ,这种方法需要专门的设备及试剂 :流式细胞仪、荧光标记的特异抗体等 ,操…     

SYBR green and TaqMan real-time PCR assays are equivalent for the diagnosis of dengue virus type 3 infections

Dengue is the most important arthropod-borne viral disease in the world. A rapid diagnostic test for dengue is warranted, and real-time polymerase chain reaction may improve diagnosis. TaqMan and Sybr Green systems were evaluated for the diagnosis of dengue virus type 3 (DENV-3) infections. Out of 77 patients with clinical suspicion of dengue infection, specific IgM antibodies were detected in 40 patients. DENV-3 was detected and quantitated in 17 IgM-positive samples by both systems. These assays were shown to be rapid, and specific for detection of DENV-3, and that for diagnostic purposes, there is no difference between these two assays.     

耐甲氧西林葡萄球菌荧光定量PCR检测方法的实验研究

目的建立一种简便、特异的mecA基因荧光定量PCR检测方法，用于耐甲氧西林葡萄球菌（MRS）的快速鉴定。方法以煮沸法快速制备DNA模板，采用SYBRGreenI随机参入法，建立mecA基因的实时荧光定量PCR检测体系。并对检测体系的敏感性、特异性和灵敏度进行评价。结果本法对纯菌落的检测敏感性和特异性分别为98．5％和96．9％，检测灵敏度可达10^1CFU／ml，最小检菌量约为3个菌／反应体系。结论本实验所设计的荧光定量PCR方法用于MRS的检测具有快捷、高敏感性、高特异性和高灵敏度的特点。适用于MRS的快速检测。     

固相酶联免疫测定法检测NS1抗原在登革病毒感染早期诊断中的应用

目的探讨固相酶联免疫测定（ELISA）法检测NS1抗原在登革病毒感染早期诊断中的应用价值。方法选取登革病毒感染早期患者血清171份,非登革病毒感染发热患者血清11份,正常人血清10份,采用ELISA法检测全部192份血清的登革病毒NS1抗原和IgM抗体;采用逆转录-聚合酶链反应-限制性内切酶酶切片段长度多态性分析（RT-PCR-RFLP）技术对发病5 d内的125份血清进行扩增和鉴定分型;并采用C6/36细胞微量培养法对发病第1、2天的41份血清进行登革病毒分离培养。结果登革病毒感染患者发病2 d内、3～5 d以及6～10 d血清NS1抗原的检出率分别是92.7%（38/41）、83.3%（70/84）、10.9%（5/46）;IgM抗体的检出率分别是2.4%（1/41）、51.2%（43/84）、97.8%（45/46）;非登革病毒感染的发热患者及正常人血清中,有1例疟疾患者血清登革病毒IgM抗体呈阳性,NS1抗原无一例阳性。RT-PCR在登革病毒感染患者发病第1、2天和3～5天的检出率分别是85.4%（35/41）、83.3%（70/84）;登革病毒感染患者发病第1、2天血清的病毒分离培养阳性率分别是80.0%（16/20）、38.1%（8/21）,总分离率58.5%（24/41）;RT-PCR-RFLP分型鉴定技术及间接免疫荧光法（IFA）均证实2006年广州流行株为登革Ⅰ型病毒。结论ELISA法检测登革病毒NS1抗原操作技术成熟,且具有敏感性高、特异性好的特点,对登革病毒感染的早期诊断和疫情的早期控制具有重要意义,适合于基层医疗机构常规应用。     

SYBR Green Ⅰ联合TaqMan荧光定量PCR检测HBV-DNA的意义

目的探索SYBR GreenⅠ联合TaqMan荧光定量PCR检测HBV-DNA的意义。方法选择浓度为10^8.48、10^5.70和10^3.70copies/ml的3种HBV-DNA阳性血清和〈1×10^3.0copies/ml的阴性血清各1份,在TaqMan-PCR混合反应体系中加入SYBR Green Ⅰ组成双荧光PCR（TaqMan＋SYBR Green Ⅰ组）,同时进行TaqMan和SYBR Green Ⅰ的单荧光PCR（分别为TaqMan组和SYBR Green Ⅰ组）,设置同一PCR和熔解曲线的循环参数,检测HBV-DNA含量及其Tm,每种方法一次检测每份血清5次。结果TaqMan＋SYBR Green Ⅰ组检测的HBV-DNA阳性血清均为阳性,其平均含量为10^8.55±0.32、10^5.79±0.29、10^3.81±0.30,与TaqMan组的10^8.49±0.31、10^5.69±0.34、10^3.72±0.26copies/ml0.320.290.300.310.300.25对应浓度值取10对数比较,无统计学意义（t=0.31、0.54和0.27,P〉0.05）;与SYBR Green I组的10^8.41±0.35,10^5.21±0.34和10^3.26±0.26copies/ml（不含未检出的两次血清）比较,除高浓度外,中低浓度有统计学意义（t=2.90和0.340.262.62,P〈0.05）。TaqMan＋SYBR Green I组和SYBR Green Ⅰ组阳性血清均出现明显熔解曲线,熔解温度（Tm）分别为71.8℃、72℃和79.8℃,阴性血清未出现扩增曲线和Tm值。结论SYBR Green Ⅰ联合TaqMan-PCR检测HBV-DNA时,具有能维持TaqMan-PCR的高灵敏度、特异性更强,并能同时检测HBV-DNATm的特点,为HBV的DNA多态性分析,尤其是在HBV基因分型方面提供了新的检测思路。     

人3型腺病毒荧光定量PCR检测方法的建立

目的通过建立人3型腺病毒荧光定量PCR检测方法,快速鉴定人3型腺病毒感染,为早期诊断提供依据。方法以人3型腺病毒感染的细胞和常见的呼吸道消化道感染的病原体为研究对象,根据病毒六邻体高度保守的序列,设计荧光定量PCR反应体系,并分析实验的敏感性和特异性。结果人3型腺病毒TCID50细胞培养液中病毒核酸最低检出稀释度是10^-6,对应的拷贝数分别是5．802×10^3copies／mL和6．968×10^2copies／mL．呼吸道和消化道感染常见的病原体未出现交叉反应。结论荧光定量PCR的应用,可有效缩短检测时间,提高检测的敏感度。     

Detection of Gallibacterium anatis by TaqMan fluorescent quantitative PCR

To better understand the prevalence of Gallibacterium anatis in different poultry species, a rapid and accurate method was developed to detect G. anatis using a TaqMan fluorescent quantitative polymerase chain reaction (qPCR). Specific primers and a TaqMan probe were designed based on the reference gtxA gene sequence. The qPCR standard curve showed a good linear relationship, and the method showed good reproducibility, sensitivity, and specificity, indicating its suitability for G. anatis identification and quantitative analysis. A comparison of the detection results in 160 clinical swab samples showed that the detection rate (54.4%) of the qPCR for G. anatis was better than that of two conventional methods: gyrB gene-based qPCR for G. anatis (51.9%) and culture-based identification (34.4%). G. anatis was detected in layer chicken (77.3%), Silkie chicken (72.7%), and duck (27.1%) with relatively high detection rates, whereas dove (8.8%) and quail (3.0%) showed lower detection rates, indicating the different prevalence of G. anatis in different fowl species.     

Parvovirus B19 infection in pregnancy: quantitative viral DNA analysis using a kinetic fluorescence detection system (TaqMan PCR)

Human parvovirus B19 infections are common in the general population, and infection during pregnancy may cause hydrops fetalis and fetal death. To initiate adequate treatment, accurate laboratory diagnosis is essential. The most sensitive tests are nested PCR systems, but these assays provide semiquantitative results at best. A parvovirus B19 DNA assay was developed based on the real time TaqMan PCR. This method was calibrated on the basis of serial plasmid dilutions and tested with an international parvovirus B19 standard. The assay was capable of quantifying parvovirus B19 DNA from one to about 5 x 10(7) genome equivalents per reaction (corresponding to 100 to 5 x 10(9) genome equivalents per ml serum). Samples from 51 pregnant women with suspected acute parvovirus B19 infection were tested, and positive PCR results were obtained in at least one of the materials investigated in 41 cases. The median viral DNA load in maternal blood samples was 1.3 x 10(4) copies/ml (range 7.2 x 10(2)-2.6 x 10(7)). Maternal virus DNA concentration was not associated with the presence of maternal symptoms and/or fetal complications. As the stage of infection was not known in the majority of cases, our data do not exclude an association between peak levels of parvovirus B19 DNA and the development of complications. Maternal sera and corresponding fetal material were available for concurrent testing from 15 DNA-positive cases: in most fetal samples, viral DNA concentrations were several orders of magnitude higher (up to 2.1 x 10(12) copies/ml) compared to the corresponding maternal blood samples.     

Quantification of Epstein-Barr virus load in peripheral blood of human immunodeficiency virus-infected patients using real-time PCR

Epstein-Barr virus (EBV) reactivation is more likely to occur in immunocompromised patients with subsequent higher susceptibility to EBV-associated lymphoproliferations. In contrast to transplant recipients, limited data are available concerning the EBV load in HIV-infected patients, with or without AIDS-related non-Hodgkin's lymphomas. We developed a TaqMan real-time PCR assay, allowing both the EBV genome and a cellular gene to be quantified in order to obtain a reliable normalized measurement of the EBV load in peripheral blood mononuclear cells (PBMCs). With a wide 6-log(10) quantification range and inter-assay variations of less than 24%, this quantitative PCR was sufficiently accurate and reproducible for routine follow-up. The EBV load was determined in PBMCs from 113 HIV-infected patients, 11 patients with primary HIV infection and 24 HIV-seronegative healthy controls. The rates of EBV detection were similar in the three groups. However, EBV loads were higher in the HIV-infected group (P < 0.00001) except for the patients with primary HIV infection. Unexpectedly, EBV loads were not correlated with the clinical stages of HIV infection or HIV replication, and did not depend on the degree of immunodepression, as judged by CD4+ counts. This study contributes towards the definition of the baseline EBV load during HIV infection and stresses the broad inter-individual variability of the EBV load in HIV-infected patients. Real-time PCR provides a useful tool that can be used in further longitudinal studies to assess the relevance of the EBV load to identify HIV-infected patients with a high risk of EBV-associated lymphoproliferations.     

Clinical evaluation of multiplex real-time PCR panels for rapid detection of respiratory viral infections

Respiratory viral infections are one of the leading causes of morbidity and mortality, particularly in children, the elderly and immunocompromised persons. Rapid identification of viral etiology is critical in ruling out non-viral infections, initiating antiviral treatment and limiting the spread of the infection. Multiplex assays of more than one viral gene target in a single tube have the advantage of rapid screening of a large number of potential viral pathogens in a short time. A multiplex real-time PCR assay was used in this study for detection of respiratory RNA and DNA viral infections in 728 specimens received from 585 adult and pediatric patients comprised of symptomatic and asymptomatic organ transplant recipients and non-recipients for diagnosis of respiratory illnesses and for routine clinical monitoring. Multiplex PCR was more sensitive than the multiplex immunofluoresence culture assay (R-mix) and also detected additional respiratory viruses that were not covered by the R-mix panel. The number of respiratory viruses detected in symptomatic patients was significantly higher than asymptomatic patients in both adult and pediatric patients. Herpesviral infections were the predominant cause of lower respiratory tract infection in the organ transplant recipients, whereas respiratory syncytial virus was the most common pathogen in non-transplant patients particularly children. Multiplex real-time PCR for detection of respiratory viruses has the potential for rapid identification of viral pathogens. In this era of emerging viral infections, addition of newer viral targets to the multiplex PCR panels will be beneficial in determining both patient management and public health epidemiology.