Detection of circulating hepatocellular carcinoma cells in peripheral venous blood by reverse transcription-polymerase chain reaction

Objective: To detect circulating hepatocellular carcino-ma by demonstrating hepatocellular carcinoma cells orhepatocyte-associated mRNA in the nuclear cell com-ponent of peripheral blood (PBL).Methods: Peripheral blood (5 ml) samples were ob-tained from 93 patients with hepatocellular carcinoma(HCC) and from 33 control subjects (9 with liver cir-rhosis after hepatitis B,14 with chronic hepatitis B,10with normal liver function). To identify HCC cells inperipheral blood, liver-specific human alpha-fetopro-tein (AFP) mRNA was amplified from total RNA ex-tracted from whole blood by reverse transcription-polymerase chain reaction.Results: AFPmRNA was detected in 50 blood samplesfrom the HCC patients (50/93, 53.8%). In contrast,there were no clinical control patients whose samplesshowed detectable AFPmRNA in PBL. The presence ofAFPmRNA in blood seemed to be correlated with thestage (by TNM classification) of HCC, the serum AFPvalue, and the presence of intrahepatic metastasis,portal vein thrombosis, tumor diameter and/or distantmetastasis. In addition, AFPmRNA was detected in theblood of 21 patients with metastasis at extrahepaticorgans (100%) in contrast to 29 (40.3%)of 72 pa-tients without metastasis.Conclusion: The presence of AFPmRNA in peripheralblood may be an indicator of malignant hepatocytes,which might predict hematogenous spreading metasta-sis of tumor cells in patients with HCC.

Detection of the Pandemic H1N1/2009 Influenza A Virus by a Highly Sensitive Quantitative Real-time Reverse-transcription Polymerase Chain Reaction Assay

A quantitative real time reverse-transcription polymerase chain reaction (qRT-PCR) assay with specific primers recommended by the World Health Organization (WHO) has been widely used successfully for detection and monitoring of the pandemic H1N1/2009 influenza A virus. In this study, we report the design and characterization of a novel set of primers to be used in a qRT-PCR assay for detecting the pandemic H1N1/2009 virus. The newly designed primers target three regions that are highly conserved among the hemagglutinin (HA) genes of the pandemic H1N1/2009 viruses and are different from those targeted by the WHO-recommended primers. The qRT-PCR assays with the newly designed primers are highly specific, and as specific as the WHO-recommended primers for detecting pandemic H1N1/2009 viruses and other influenza viruses including influenza B viruses and influenza A viruses of human, swine, and raccoon dog origin. Furthermore, the qRT-PCR assays with the newly designed primers appeared to be at least 10-fold more sensitive than those with the WHO-recommended primers as the detection limits of the assays with our primers and the WHO-recommended primers were 2.5 and 25 copies of target RNA per reaction, respectively. When tested with 83 clinical samples, 32 were detected to be positive using the qRT-PCR assays with our designed primers, while only 25 were positive by the assays with the WHO-recommended primers. These results suggest that the qRT-PCR system with the newly designed primers represent a highly sensitive assay for diagnosis of the pandemic H1N1/2009 virus infection.

Quantification of Porcine Follicle-stimulating Hormone Receptor Messenger Ribonucleic Acid by Reverse Transcription competitive Polymerase Chain Reaction

An easy and reliable method was developed for construction and quantification of competitive templates, which shared the same sequence as the amplified target DNA except for a 20 bp insertion in the middle by recombinant polymerase chain reaction (PCR). Among the advantages of competitive PCR is that any predictable or unpredictable variable that affects amplification has the same effect on both target and competitor species and that the final ratio of amplified products reflects exactly the initial targets. The utilization of a thermostable reverse transcriptase in the RT step was proposed to overcome the problem of the efficiency of target cDNA synthesis. In addition, to obtain reliable measurements, it was recommended to perform four PCR with amounts of competitive template flanking the concentration of the target mRNA.

Exogenous reference gene normalization for real-time reverse transcription-polymerase chain reaction analysis under dynamic endogenous transcription

Quantitative real-time reverse transcription-polymerase chain reaction （qPCR） is widely used to investigate transcriptional changes following experimental manipulations to the nervous system. Despite the widespread utilization of qPCR, the interpretation of results is marred by the lack of a suitable reference gene due to the dynamic nature of endogenous transcription. To address this inherent deficiency, we investigated the use of an exogenous spike-in mRNA, luciferase, as an internal reference gene for the 2ct normalization method. To induce dynamic transcription, we systemically administered capsaicin, a neurotoxJn selective for C-type sensory neurons expressing the TRPV-1 receptor, to adult male Sprague-Dawley rats. We later isolated nodose ganglia for qPCR analysis with the reference being either exogenous luciferase mRNA or the commonly used endogenous reference 13-111 tubulin. The exogenous luciferase mRNA reference clearly demonstrated the dynamic expression of the endogenous reference. Furthermore, variability of the endogenous reference would lead to misinterpretation of other genes of interest. In conclusion, traditional reference genes are often unstable under physiologically normal situations, and certainly unstable following the damage to the nervous system. The use of exogenous spike-in reference provides a consistent and easily implemented alternative for the analysis of qPCR data.

Small Amplicons Mutation Library for Vaccine Screening by Error-Prone Polymerase Chain Reaction

Library construction is a common method used to screen target genes in molecular biology.Most library constructions are not suitable for a small DNA library(<100 base pair(bp))and low RNA library output.To maximize the library’s complexity,error-prone polymerase chain reaction(PCR)was used to increase the base mutation rate.After introducing the DNA fragments into the competent cell,the library complexity could reach 109.Library mutation rate increased exponentially with the dilution and amplification of error-prone PCR.The error-prone PCR conditions were optimized including deoxyribonucleotide triphosphate(dNTP)concentration,Mn^(2+)concentration,Mg^(2+)concentration,PCR cycle number,and primer length.Then,a RNA library with high complexity can be obtained by in vitro transcription to meet most molecular biological screening requirements,and can also be used for mRNA vaccine screening.

Detection of hepatocellular carcinoma cells in the peripheral blood with reverse--transcription polymerase chain reaction

In order to detect circulating cells of hepatocellular carcinoma(HCC) in the peripheral blood with reverse transcripition polymerase chain reaction (RT-PCR ), alpha-fetoprotein (AFP ) mRNA was tested in the blood samples of 113 cases of HCC and 69 controls (including 30 cases of liver cirrhosis, 9 cases of metastatic liver cancer and 30 normal subjects). 20/43 (46. 5% ) cases of HCC and 2/30 (6. 7% ) cases of liver cirrhosis are positive and the cases of nletastatic liver cancer and normal controls were negative for human AFP(hAFP) rnRNA. The presence of hAFP mRNA in the peripheral blood seems to be correlated with intrahepatic and distant nletastasls of HCC and portal vein thrombosis. It is concluded that the presence of hAFP mRNA in the peripheral hloocl is an indicator of circulating HCC cells and can be used to diagnose the rnetastasisof HCC through henlatogenous route and RT-PCR amplification of hAFP mRNA is a sensitive and specificprocedure for detecting circulating cells of HCC.

复合探针实时荧光RT-PCR法检测小儿上呼吸道感染甲型流感病毒的价值

目的 分析小儿上呼吸道感染甲型流感病毒应用复合探针实时荧光反转录聚合酶链反应(RT-PCR)法检测的临床价值。方法选择2023年1月至2023年12月流感监测信息系统两家监测点上呼吸道感染甲型流感病毒感染的患儿80例监测标本进行回顾性分析,均开展复合探针实时荧光RT-PCR法检测,分析其诊断价值。结果 根据监测标本最终诊断结果显示,阳性标本68例、阴性标本12例。经复合探针实时荧光RT-PCR法检出67例,检出率为83.75%,敏感度为95.59%、特异度为83.33%、准确度为93.75%、阳性结果预测值为97.01%、阴性结果预测值为76.92%;批间批内变异系数均小于5%。结论 小儿上呼吸道感染甲型流感病毒应用复合探针实时荧光RT-PCR技术具有较高的敏感度、特异度及准确度,且检查结果快速,可为小儿上呼吸道感染甲型流感病变提供可靠的诊断,有利于制订合理的治疗方案。

帕利亚姆病毒实时荧光定量RT-PCR检测方法的建立与应用

本研究拟建立帕利亚姆病毒(Palyam virus,PALV)血清型特异性实时荧光定量RT-PCR(qRT-PCR)方法用于临床样本或媒介中PALV血清型鉴定。根据我国流行PALV毒株的基因节段2序列,设计扩增引物和TaqMan探针,建立PALV血清型特异型qRT-PCR方法,对方法的特异性、灵敏性与重复性进行评估;以我国分离的28株PALV和90份核酸阳性血液样本评估检测方法的可靠性;利用建立的方法对采集库蠓样本中携带的PALV进行血清型鉴定。结果显示,建立的PALV血清型qRT-PCR检测方法具有良好的特异性与灵敏性,可检出核酸拷贝数下限在22至28 copies·μL^(-1)。对28株PALV的qRT-PCR检测结果与病毒测序鉴定结果一致;对PALV不同感染阶段哨兵动物血液(90份)中的qRT-PCR鉴定结果与分离病毒的血清型鉴定结果一致;建立的方法可准确鉴定库蠓中携带PALV的血清型。本研究建立的PALV血清型qRT-PCR定型方法具有良好的特异强、敏感性与重复性,可用于PALV感染动物与媒介中PALV血清型的鉴定,具有良好的应用价值。

基于直扩RT-PCR技术的寨卡病毒快速检测方法的建立

目的建立基于直扩实时荧光定量逆转录聚合酶链反应(RT-PCR)技术的寨卡病毒快速检测方法。方法采用特殊功能的DNA聚合酶,以及优选PCR增强剂,以此建立直扩RT-PCR技术的寨卡病毒快速检测5种样本(全血、血清、唾液、咽拭子和尿)的方法。结果5种样本检测限分别为血清103 PFU/mL,尿、咽拭子和唾液102 PFU/mL,全血104 PFU/mL,标准曲线的拟合优度的可决系数均在0.98以上,扩增效率均在90%~110%;寨卡病毒核酸成功扩增,非寨卡病毒核酸均未能扩增;尿、全血和唾液样本的重复性实验中106 PFU/mL和102 PFU/mL两个浓度的6个重复Ct值的变异系数均<5%。该研究建立的直扩RT-PCR技术的寨卡病毒检测方法与常规RT-PCR技术的检测结果一致,8个寨卡病毒样本,均只检测出2个血清样本,其余62个非寨卡病毒样本及12个阴性样本均未得到扩增。结论成功建立基于直扩RT-PCR技术的寨卡病毒快速检测方法,该方法简便快捷且灵敏度高、特异度强。

RT-PCR法在沙门菌检测及血清分型鉴定中的应用价值研究

目的:探讨反转录-聚合酶链反应(RT-PCR)法在沙门菌检测及血清分型鉴定中的应用价值。方法:选择2022年8月至2024年1月本疾控中心收治的456例腹泻患者的粪便标本,均行细菌培养和RT-PCR检测,记录RT-PCR鉴定沙门菌血清分型结果,以细菌培养结果作为金标准,分析RT-PCR鉴定沙门菌的价值及其与细菌培养的一致性,对比细菌培养、RT-PCR鉴定沙门菌的费用及操作时间。结果:456例腹泻中经细菌培养共检出沙门菌78株,RT-PCR检出85株,RT-PCR检测敏感度为97.44%(76/78),特异度为96.83%(366/378),准确度为96.93%(442/456),阳性预测值为89.41%(76/85),阴性预测值为99.46%(366/368);RT-PCR鉴定沙门菌结果与细菌培养一致性较高(kappa值=0.897,P<0.001);RT-PCR鉴定结果与细菌培养完全一致有73株,符合率为93.59%,其中里森沙门菌、鼠伤寒沙门菌、德尔卑沙门菌、姆班达卡沙门菌4种优势血清型结果完全一致,而与细菌培养鉴定不一致菌株5株;RT-PCR鉴定沙门菌操作时间为(0.30±0.07)天,费用(100.22±6.52)元,细菌培养鉴定沙门菌的操作时间为(2.82±0.25)天,费用为(300.52±12.16)元,RT-PCR鉴定沙门菌的费用及操作时间均低于细菌培养,差异有统计学意义(P<0.001)。结论:RT-PCR法可准确检出沙门菌,判断沙门菌血清分型,与细菌培养结果具有较高的一致性,且操作用时短、所需费用低,可应用于沙门菌检测。

Abnormal expression of VEGF and its gene transcription status as diagnostic indicators in patients with non-small cell lung cancer

Objective Angiogenesis is known to be essential for the survival,growth,invasion,and metastasis of lung cancer cells. Vascular endothelial growth factor(VEGF) is an important factor regulating angiogenesis of non-small cell lung cancer(NSCLC); however,its pathologic features and significance are unclear. In this study,the tissue VEGF expression levels and its gene transcriptional status,as well as circulating VEGF levels,were investigated in patients with lung disease. Methods VEGF protein and m RNA expression levels in 38 lung tissue samples were analyzed by immunohistochemistry and reverse transcription-polymerase chain reaction(RT-PCR),respectively. Circulating VEGF levels were detected quantitatively by an enzyme linked immuno-sorbent assay. Results The level of VEGF expression was significantly higher in lung cancer tissue than in the corresponding paracancerous or non-cancerous tissues. The average level of VEGF-positive staining was 76% in tissue samples from NSCLC patients; the levels were 89% in tissue samples from stage III patients and 92% in stage IV patients. High VEGF expression was also evident in cases with lymph node metastasis(84%),distant metastasis(90%),and lower differentiation degree(89%). VEGF m RNA in cancerous tissues was represented predominantly by the VEGF121 and VEGF165 isoforms. Circulating VEGF levels were significantly higher in NSCLC patients [(840 ± 324) pg/m L] than in patients with benign lung diseases [(308 ± 96) pg/m L] or in healthy individuals serving as controls [(252 ± 108) pg/m L]. Conclusion The over-expression of lung VEGF and its gene transcription status should be useful molecular indicators for NSCLC diagnosis.

柯萨奇病毒A组5型实时荧光RT-PCR检测方法的建立与评价

目的建立柯萨奇病毒A组5型(CVA5)特异的一步法实时荧光反转录聚合酶链反应(RT-PCR)核酸检测方法。方法以流行于遵义地区的CVA5病毒株和NCBI基因库中随机下载的CVA5 VP1基因序列作为参考序列,分析这些序列的保守区域,在其保守区设计特异性的引物与Taqman探针,建立检测CVA5的一步法实时荧光RT-PCR。通过构建含CVA5 VP1保守区域的重组质粒,绘制标准曲线,并对检测方法的灵敏度、特异性、重复性及临床样本检出限进行评价。利用该方法对遵义地区273份未明确分型的肠道病毒阳性样本进行检测,将检出的部分CVA5阳性产物进行测序。结果成功建立一种基于实时荧光RT-PCR的CVA5检测方法,该方法在10^(4)~10^(9)copy/mL范围内具有良好的线性关系(R 2>0.999),平均扩增效率为102.26%。灵敏度高,对临床样本的检出限为103copy/mL。该方法的特异性强,与柯萨奇病毒A组2型(CVA2)、柯萨奇病毒A组4型(CVA4)、柯萨奇病毒A组6型(CVA6)、丙型肝炎病毒、呼吸道合胞病毒和鼻病毒等均不发生交叉反应。重复性实验的变异系数低于1.5%。273份未明确分型肠道病毒阳性样本中共检出25份CVA5,占未明确分型阳性样本的9.16%。结论该研究建立的一步法CVA5RT-PCR检测方法灵敏度高、特异性强、重复性好,可用于CVA5的检测。

Quantification of mRNA Levels by Fluorescently Labelled Reverse Transcription Competitive PCR

A reproducible,quantitative,non-radioactive method for the analysis of mRNA expression is described.After RNA preparation and cDNA synthesis,the cDNA was co-amplified with an internal standard in the same PCR system.The PCR products containing both targen and internal standard amplificates were electrophoresed and detected on an ABI 377 DNA Sequencer.For each sample,β-actin was also quantified by an identical procedure to compensate for relative differences between samples in the integrity of the individual RNA samples and for variations in reverse transcription.Due to the linear relationship between cDNA content and PCR product ratio of target cDNA template and competitive standard,a single PCR reaction was sufficient for quantification of a sample.The experimental results showed that the method is a mRNA quantitative RT-PCR method with high sensitivity and good reproducibility.It can be used in large-scale accurate quantitative analyses of mRNA expression of any gene.

荧光定量RT-PCR法在病原微生物检验中的应用价值

目的:分析荧光定量逆转录聚合酶链式反应(RT-PCR)法在病原微生物检验中的应用价值。方法:选取2019年4月-2021年1月在长沙市中心医院进行病原微生物检测的46例疑似微生物感染患者作为研究对象,均实施常规RT-PCR法、荧光定量RT-PCR法检测,统计两种方法的检验结果;以特殊染色镜检结果作为“金标准”,比较两种检验方法检测微生物感染的准确度、灵敏度、特异度以及对各类病原微生物的检出率,统计受试者对两种检验方法的满意度。结果:特殊染色镜检结果显示,46例受试者病原微生物感染阳性43例,阴性3例。两种检验方法检测微生物感染的准确度、特异度比较,差异无统计学意义(P>0.05);荧光定量RT-PCR法检测灵敏度高于RT-PCR法,差异有统计学意义(P<0.05)。特殊染色镜检结果显示,43例病原微生物感染患者中,衣原体感染7例,支原体感染8例,寄生虫感染9例,细菌感染7例,真菌感染5例,病毒感染7例,两种检验方法对各类病原微生物的检出率及总检出率比较,差异无统计学意义(P>0.05)。受试者对荧光定量RT-PCR法检验总满意度高于RT-PCR法,差异有统计学意义(P=0.026)。结论:荧光定量RT-PCR法在病原微生物检验中的应用价值较好,能够提高检测灵敏度,受试者满意度高。

RT-PCR技术在新型冠状病毒核酸检测的应用及质量评价分析

在新型冠状病毒感染患者的诊断中,采取有效检测方式进行及早诊断尤为重要。逆转录-聚合酶链式反应(RT-PCR)技术有较高灵敏度和特异度。本文分析临床应用RT-PCR技术检测新型冠状病毒的常见问题和应对策略,旨在为疫情防控常态化形势下临床实验室正确、高效开展新型冠状病毒检测提供参考意见。

饮食习惯与肥胖患儿性早熟的相关性分析

目的探讨饮食习惯与肥胖患儿性早熟的相关性分析。方法选取苏州市吴中人民医院2019年3月至2022年3月期间收治的72例性早熟肥胖患儿作为观察组,另选取同期体检的健康肥胖儿童71例作为常规组。采用实时-逆转录荧光定量聚合酶链反应(RT-qPCR)检测两组外周血miR-125b水平,分析患儿饮食习惯。通过比较两组肥胖儿童的外周血miR-125b、饮食习惯,采用Logistic回归分析法分析外周血miR-125b、饮食习惯与肥胖患儿性早熟的关系。结果观察组外周血miR-125b表达水平高于常规组,差异有统计学意义(P<0.05)。观察组饮食没规律、荤多素少、高添加剂食品占比均高于常规组,差异有统计学意义(P<0.05)。观察组女性患儿、不良饮食习惯占比高于常规组,且经多因素分析显示外周血miR-125b表达水平、女性、不良饮食习惯是肥胖患儿性早熟的独立危险因素,差异有统计学意义(P<0.05)。结论肥胖患儿性早熟外周血miR-125b表达水平高于健康肥胖儿童,不良饮食习惯高于健康肥胖儿童,外周血miR-125b表达水平偏高、不良饮食习惯偏低均为肥胖患儿性早熟的影响因素。

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。

逆转录-聚合酶链反应(RT-PCR)检测轮状病毒

为了给轮状病毒感染的诊断和流行病学研究提供更为敏感和可靠的手段，选取Ａ组轮状病毒ＶＰ７基因上的２段高度保守序列作为引物，在优化逆转录－聚合酶链反应（ＲＴ－ＰＣＲ）条件的基础上，建立了检测轮状病毒的ＲＴ－ＰＣＲ方法。通过对比试验，确定了ＰＣＲ的最优模式：９４℃变性１ｍｉｎ→５５℃退火１ｍｉｎ→７２℃延伸２ｍｉｎ，３０个循环后再在７２℃下延伸１０ｍｉｎ。用此模式进行了ＲＴ－ＰＣＲ的特异性和敏感性试验。检测的６株轮状病毒分离株（牛ＨＮ－７、ＢＲＶ００７、ＢＲＶ０１４、ＢＲＶ６５５５、猪Ｌｉ９９、Ｎａｎ８６）及２株参考株（牛ＮＣＤＶ、猴ＳＡ１１），都能扩增出唯一的３４２ｂｐ的目的条带；对猪流行性腹泻病毒（ＰＥＤＶ）及传染性胃肠炎病毒（ＴＧＥＶ）感染猪的粪样、正常ＭＡ１０４细胞检测结果均呈阴性；检测的敏感度可达１ｐｇ水平。对４０份猪、牛、兔的腹泻粪样检测，３０份呈阳性，而用作平行对照的夹心ＥＬＩＳＡ法检测，有２５份呈阳性，两者符合率为８７．５％。两法检测不符的５份粪样的ＰＣＲ扩增产物，用地高辛标记探针进行了斑点杂交，结果均呈阳性，表明ＲＴ－ＰＣＲ法比ＥＬＩＳＡ法敏感性高。

RT-PCR检测猪瘟病毒初探

本研究建立了反转录聚合酶链反应 ( RT PCR)技术检测猪瘟病毒 ( Hog Cholera Virus,HCV)方法。合成的二对引物 HCV 1 / HCV 2和 HCV A1 / HCV A2成功地扩增兔化弱毒株、法国株和石门株的核酸 ,并对采自博白县 3个、贵港市 1个和武宣县 1个猪场共 1 3份病料进行检测。结果从博白县和贵港市的 1 1份材料中检测到 HCV的核酸。

半定量RT-PCR检测细胞因子表达的研究

目的 :建立一种客观、敏感的检测IL 2 /IL 4细胞因子基因表达变化的方法。 方法 :采用TRIzol试剂提取免疫排斥 /免疫耐受大鼠脾脏组织总RNA ,分光光度计法定量。取 2 μg总RNA ,采用RT PCR法逆转录 扩增IL 2、IL 4和内参照 β actincDNA ,扩增产物经电泳分离后 ,用凝胶图像分析仪照相和扫描分析 ,检测其相对表达量。 结果 :RT PCR产物经电泳后 ,β actin、IL 2和IL 4分别在 2 2 6bp、342bp和 332bp处出现明显条带 ,与预定条带大小相一致 ;免疫耐受组IL 4与免疫排斥组IL 2的表达有明显差异 ,在免疫耐受组中IL 4表达增高 ,而在免疫排斥组中IL 2表达增高 ,内参照 β actin扩增条带亮度在两组中相同 ,PCR产物量与扩增初始模板量之间存在良好的对应关系。 结论 :半定量RT PCR检测是一种从少量细胞中快速、简便。