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.

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.

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.

Hepatitis C virus in human B lymphocytes transformed by Epstein-Barr virus in vitro by in situ reverse transcriptase-polymerase chain reaction

AIM To study persistence and replication ofheltitis C virus (HCV) in patients' peripheralblood mononuclear cells (PBMC) cultured invitro.METHODS Epstein-Barr virus (EBV) was usedto transform the hepatitis C virus from a HCVpositive patient to permanent lymphoblastoidcell lines (LCL). Positive and negative HCV RNAstrands of the cultured cells and growth mediawere detected by reverse transcriptase-polymerase chain reaction ( RT-PCR ) eachmonth. Core and NS5 proteins of HCV werefurther tested using immunohistochemical SPmethod and in situ RT-PCR.RESULTS HCV RNA positive strands wereconsistently detected the cultured cells for oneyear. The negative-strand RNA in LCL cells andthe positive-strand RNA in supernatants wereobserved intermittently. Immunohistochemicalresults medicated expression of HCV NS3 and Cproteins in LCL cytoplasm mostly. The positivesignal of PCR product was dark blue and mainlylocalized to the LCL cytoplasm. The RT-PCRsignal was eliminated by overnight RNasedigestion but not DNase digestion.CONCLUSION HCV may exist and remainfunctional in a cultured cell line for a longperiod.

Detection of Human Parvovirus B19 Nonstrutural Protein DNA by Nested-Polymerase Chain Reaction in Gravida Serum and Pregnant Tissues

A new nested-polymerase chain reaction （nested-PCR） assay was developed to detect human parvovirus B19 DNA corresponding to the nonstructural protein in clinical specimens in a routine diagnostic laboratory. The sensitivity of this highly specific assay was up to 0. 005 fg of B19 DNA. Parvovirus B19 was identified in sera of 20 pregnant women with abnormal pregnant outcome. Among these 20 cases, intrauterine parvovirus infection did exist in 7 pregnant women because parvovirus B19 DNA was detected in the pregnant tissues of them such as placenta tissues, chorionic villi, amniotic fluid, fetal spleen, liver and abdominal fluids.

Detection and amplification of Helicobacter pylori urease gene A in gastric biopsies by using nested polymerase (?)hain reaction

A nested polymerase chain reaction(N-PCR)for the spegific detection of Helicobacterpylori(H.pylori)was developed with two primer pairs(nested primers)derived from ureasegene A of H.pylori.The N-PCR was used to detect 21 different samples of H.pylori including20 clinical isolates and 1 reference strain NCTC 14126,but it was negative for other bacterialspecies,showing the N-PCR assay to be 100% specific.Tenfold serial dilution experiments re-vealed the detection of as little as 0.1 fg of H.pylori DNA by N-PCR.To evaluate the PCR as-say for clinical samples,gastric biopsies were tested with N-PCR,and the results were comparedwith those of culture,urease test and histologic examination(reference standard,RS).In 30biopsy specimens,H.pylori DNA sequences were detected by PCR in all of 20(100%)positivetissue and none of the 10 negative tissues.PCR is a specific and sensitive method that can detectthe presence of H.pylori without the need for culture and would have significant importance di-agnostically and epidemiologically.

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.

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。

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。

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。

进口锦鲤暴发病病原的nested-PCR鉴定

为了查明锦鲤暴发性疾病的病因 ,将患病锦鲤的脑、肝、脾和肾等组织悬液接种到CO、CK和EPC等鱼类细胞系中培养 ,均未发现细胞病变 ;从病灶中取样进行病原菌的分离和培养 ,证明锦鲤有副溶血弧菌和嗜水气单胞菌的感染。制备锦鲤疱疹病毒 (KHV)的 2对引物KHV9/ 5F和KHV9/ 5R ,KHV1和KHV2 ,用嵌套式聚合酶链式反应 (nested -PCR)在脑和脾脏组织的抽提物中扩增出长度为 4 12bp的特异性的DNA片段。将该片段的nested -PCR扩增产物纯化后 ,克隆、测序。用NCBI -Blast软件将测序结果在Genebank中进行搜寻、比较 ,结果发现与注册号为AF4 1180 3的KHV基因序列的一部分片段有 99%的同源性。因此初步判断这次锦鲤暴发性疾病是由KHV引起的 。

新型冠状病毒亚基因组RNA检测方法的建立及性能评估

目的建立检测新型冠状病毒(新冠病毒)亚基因组RNA(subgenomic RNA,sgRNA)的方法,并对所建立的方法进行性能评估。方法根据新型冠状病毒sgRNA序列设计引物和探针,建立检测sgRNA的实时荧光逆转录PCR(reverse transcription polymerase chain reaction,RT-PCR)方法,对所建立的方法进行优化,包括引物、探针的浓度及比例、延伸温度、反应体积和模板量。并对所建立的方法进行性能评估,包括最低检测限、灵敏度、特异性和重复性。对临床样本进行新冠病毒sgRNA和基因组RNA(genomic RNA,gRNA)检测,并对检测结果进行分析。结果建立了检测新冠病毒sgRNA的RT-PCR方法。所建方法的最低检测限为100 copies/mL,对常见病原体的检测结果均为阴性。对高、中、低浓度样本sgRNA进行检测,CV均<5%。115例疑似新冠病毒感染者的咽拭子样本sgRNA为阳性(115/330,阳性率为34.85%)。gRNA-N Ct值<30时,sgRNA-N的阳性率为100.00%;gRNA-N的Ct值介于30~32时,sgRNA-N的阳性率为68.75%;gRNA-N的Ct值介于32~35时,sgRNA-N的阳性率为44.44%;gRNA-N的Ct值>35时,sgRNA-N均为阴性。结论建立了新冠病毒sgRNA的RT-PCR检测方法,方法灵敏、特异、重复性好。

新型冠状病毒Omicron I1566V突变位点MS2噬菌体病毒样颗粒的构建

目的构建新型冠状病毒Omicron I1566V突变位点MS2噬菌体病毒样颗粒。方法选取并合成带有6×His标签的MS2噬菌体的衣壳蛋白(CP)、成熟蛋白(A蛋白)及Omicron I1566V突变基因序列,插入pACYCDuet-1质粒构建重组载体,通过原核系统诱导表达目的蛋白,纯化重组蛋白后利用透射电镜对蛋白质进行物理表征,最后通过反转录聚合酶链反应(RT-PCR)检测病毒样颗粒的热稳定性及耐核酸酶水解能力。结果成功构建包含有6×His标签的CP、A蛋白和Omicron I1566V突变基因序列的重组载体,经限制性内切酶BamHⅠ和KpnⅠ酶切鉴定和测序验证,结果均与预期相符。经诱导并纯化后,通过电镜观察到了大小均匀、直径为23~28 nm的病毒样颗粒,该病毒样颗粒经核酸酶消化后可在37℃条件下稳定储存20 d以上。结论该研究成功利用MS2噬菌体的CP和A蛋白构建了Omicron I1566V突变位点病毒样颗粒,为该突变位点的RT-PCR检测体系提供了可靠的质量保障。

Nested PCR检测微量隐孢子虫卵囊

根据隐孢子虫 18S r DNA序列 ,设计出隐孢子虫属和鼠隐孢子虫种的特异性引物 ,进行 PCR和 Nested PCR反应 ,先后分别扩增出 1条 5 4 0 bp和 1条 2 5 0 bp的条带。研究表明 ,Nested PCR具有高度的特异性和敏感性。应用Nested PCR可检测 1～ 10个鼠隐孢子虫卵囊 ,其敏感性是饱和蔗糖漂浮法的 10 5倍以上。

解脲脲原体套式（Nested）PCR检测研究

本文报告解脲脲原体（ＵＵ）的套式（ＮＥＳＴＥＤ）ＰＣＲ检测方法。经方法学考核表明，本法的特异性、灵敏度以及试剂的稳定性和对临检标本的顺应性均较好。９３份各种生殖道炎症患者之宫颈拭子标本套式ＰＣＲ检出２１份阳性（阳性率２２．６％），而市售ＰＣＲ试剂盒仅检出１份阳性（阳性率１．１％）。前者阳性检出率明显高于后者（Ｐ＜０．０１）。

Identifying the stability of housekeeping genes to be used for the quantitative real-time PCR normalization in retinal tissue of streptozotocin-induced diabetic rats

AIM:To investigate the stability of the seven housekeeping genes:beta-actin(ActB),glyceraldehyde-3-phosphate dehydrogenase(GAPDH),18s ribosomal unit 5(18s),cyclophilin A(CycA),hypoxanthine-guanine phosphoribosyl transferase(HPRT),ribosomal protein large P0(36B4)and terminal uridylyl transferase 1(U6)in the diabetic retinal tissue of rat model.METHODS:The expression of these seven genes in rat retinal tissues was determined using real-time quantitative reverse transcription polymerase chain reaction(RT-qPCR)in two groups;normal control rats and streptozotocininduced diabetic rats.The stability analysis of gene expression was investigated using geNorm,NormFinder,BestKeeper,and comparative delta-Ct(ΔCt)algorithms.RESULTS:The 36B4 gene was stably expressed in the retinal tissues of normal control animals;however,it was less stable in diabetic retinas.The 18s gene was expressed consistently in both normal control and diabetic rats’retinal tissue.That this gene was the best reference for data normalisation in RT-qPCR studies that used the retinal tissue of streptozotocin-induced diabetic rats.Furthermore,there was no ideal gene stably expressed for use in all experimental settings.CONCLUSION:Identifying relevant genes is a need for achieving RT-qPCR validity and reliability and must be appropriately achieved based on a specific experimental setting.

双重荧光逆转录-聚合酶链式反应与荧光逆转录-重组酶介导等温扩增快速检测食源性GⅠ型、GⅡ型诺如病毒

目的建立双重荧光逆转录-聚合酶链式反应(reverse transcription polymerase chain reaction,RT-PCR)与荧光逆转录-重组酶介导等温扩增(reverse transcription recombinase-aided amplification,RT-RAA)快速有效地检测食品中食源性GⅠ型和GⅡ型诺如病毒的方法。方法根据GⅠ型、GⅡ型诺如病毒基因组保守序列设计引探,经过一系列引探浓度筛选,建立了双重荧光RT-PCR和恒温荧光RT-RAA两种检测方法,分别从敏感性、特异性、稳定性、重复性等方面进行了比较研究;同时将这两种方法应用于实际临床样本检测中,并与GB4789.42—2016《食品安全国家标准食品微生物学检验诺如病毒检验》进行比对验证。结果建立的两种方法特异性良好,敏感性均可达10 copies/μL;双重荧光RT-PCR方法质粒梯度变异系数(coefficient of variation,CV)值在0.1%~1.5%区间,恒温荧光RT-RAA方法CV值在1.0%~10.0%区间,稳定性和重复性显示双重荧光RT-PCR优于恒温荧光RT-RAA检测方法;31份诺如病毒阳性食品核酸样本均能检出,且50份食品盲样检测结果与国标一致。结论本研究成功建立了双重荧光RT-PCR与恒温荧光RT-RAA快速检测食源性GⅠ型、GⅡ型诺如病毒方法,两种方法各有优缺点,双重荧光RT-PCR稳定性和重复性好,恒温荧光RT-RAA检测时间短,仅20 min就能完成扩增,可根据不同需求选择一种或两种作为食源性GⅠ型、GⅡ型诺如病毒的检测方法。