多重PCR技术检测沙门菌两种四环素耐药基因

应用两对特异性引物同时检测四环素耐药基因tetB和tetC通过对35株沙门菌分离株的四环素耐药性检测，表明所有沙门菌分离株均含tetC基因，与药敏试验结果阳性符合率65．7％，8株同时含有tetB基因，与药敏试验结果阳性符合率100％，tetB基因和tetC基因双阳性的菌株与药敏试验结果阳性符合率也为100％。取其中部分菌株扩增出tetB和tetC基因片段进行序列分析，5株菌的tetB基因扩增产物序列完全相同，与质粒pRT11相应序列同源性达99．7％；14株菌的tetC基因扩增产物与质粒pBR322中的相应序列同源性为100％。证实沙门菌耐药基因普遍存在，且同时含有tetB和tetC基因的菌株表现耐药。多重PCR技术同时检测两种四环素耐药基因，适合大量样本的检测，对开展沙门菌四环素多种耐药基因的分子流行病学监测提供了有效途径。     

多重聚合酶链反应快速鉴别葡萄球菌及mecA基因检测

目的：建立快速鉴定葡萄球菌及检测mecA基因的多重聚合酶链反应（PCR）诊断方法。方法：以葡萄球菌16SrRNA、金黄色葡萄球菌的nuc基因以及耐甲氧西林葡萄球菌（MRS）的mecA基因合成3对引物，采用多重PCR扩增法，快速鉴定葡萄球菌，同时判断MRS菌株。结果：107株葡萄球菌的16SrRNA基因扩增片段全部为阳性．与常规鉴定结果符合率为100％；nuc基因阳性48株。阴性59株，与金黄色葡萄球菌核酸酶试验一致；以PBP2a乳胶凝集试验结果为金标准，苯唑西林（含2％NaClMHA）及头孢西丁纸片扩散法的敏感性为98．7％和100％，特异性分别为75．0％和82．1％：PCR扩增法的敏感性和特异性均为100％。结论：多重PCR法能快速准确地从临床分离菌株中鉴别葡萄球菌，并可同步对mecA基因进行准确检测。     

多黏菌素联合替加环素对多重耐药鲍曼不动杆菌的作用

目的 探讨多黏菌素联合替加环素（tigecyclin）对多重耐药鲍曼不动杆菌体外抗菌的效果。方法 收集临床分离的50株多重耐药鲍曼不动杆菌,采用微量肉汤稀释法、棋盘法分别检测替加环素、多黏菌素单独及联合使用的最低抑菌浓度（MIC）,并计算药物联合使用抑菌浓度（FIC）指数,利用FIC指数判定替加环素和多黏菌素联用时对多重耐药鲍曼不动杆菌体外抗菌的效果。荧光定量PCR检测外排泵基因表达水平。结果 替加环素联合多黏菌素能显著降低各自MIC值,表现为协同作用的菌株占70%,表现为相加作用的占14%,表现为无关作用的占6%,拮抗作用则为10%。对联合用药不敏感的菌株,其外排泵基因（abeB,abeJ,abeG,abeM）表达水平显著高于敏感型（P<0.05）。结论 替加环素联合多黏菌素可对多重耐药鲍曼不动杆菌的感染进行治疗。     

Development, validation, and implementation of a multiplex immunoassay for the simultaneous determination of five cytokines in human serum

Quantification of biomarkers can provide important information about the safety and efficacy of candidate drugs. Unfortunately, limited sample volume and excess costs often limit analysis of multiple biomarkers. We developed, optimized, validated, and implemented a multiplex immunoassay for simultaneous measurement of multiple circulating cytokines: IL-1β, TNF, IL-6, IL-8, and IL-10.

Multiplex immuoassays were performed using the Luminex LabMAP instrument. Capture antibodies for each cytokine were covalently bound to distinct microsphere subsets distinguished by differing dye ratios. The concentration of each individual cytokine determined by measuring orange fluorescence produced by a complex of a biotinylated cytokine-specific antibody and streptavidin-phycoerythrin.

The lower limit of quantification for all assays was 20 pg/mL with the exception of IL-8 which was 100 pg/mL. The inter-assay precision was less than 25%CV for all analytes at all control levels both pre-study and in-study. The percent recovery ranged from 83 to 108% pre-study and 90 to 125% in-study. In a linearity assessment, a 15,000 pg/mL multi-analyte control could be diluted 1:50 and maintain expected accuracy.

We measured the cytokine concentrations in more than 2000 serum samples from patients with sepsis. Multiplex results for IL-6 were compared to a conventional commercially available ELISA kit. The degree of agreement between the two methods as measured by the concordance correlation coefficient was 84.5%. Multiplex results were 2.36-fold higher than ELISA values on the average. After adjusting for this mean difference, the 95% empirical limits of agreement for the ratio of individual sample values were 0.33, 2.65.

This multiplex immunoassay provided simultaneous measurement of circulating cytokines using 80% less patient specimen compared to traditional approaches and at a significantly decreased cost. Efficient use of this platform requires process improvements to fully maximize the positive impact of multiplex assays in clinical drug development.     

Designing a biochip following multiplex polymerase chain reaction for the detection of Salmonella serovars Typhimurium,Enteritidis, Infantis,Hadar, and Virchow in poultry products

Salmonella-contaminated foods, especially poultry-derived foods (eggs, chicken meat), are the major source of salmonellosis. Not only in the European Union (EU), but also in the United States, Japan, and other countries, has salmonellosis been an issue of concern for food safety control agencies. In 2005, EU regulation 1003/2005 set a target for the control and reduction of five target Salmonella enterica serovars—S. Typhimurium, S. Enteritidis, S. Infantis, S. Hadar, and S. Virchow—in breeding flocks. Thus, a simple biochip for the rapid detection of any of these five Salmonella serovars in poultry products may be required. The objectives of this study were to design S. Virchow-specific primers and to develop a biochip for the simultaneous identification of all or any of these five Salmonella serovars in poultry and poultry products. Experimentally, we designed novel polymerase chain reaction (PCR) primers for the specific detection of S. Virchow, S. Infantis, and S. Hadar. The specificity of all these primers and two known primer sets for S. Typhimurium and S. Enteritidis was then confirmed under the same PCR conditions using 57 target strains and 112 nontarget Salmonella strains as well as 103 non-Salmonella strains. Following multiplex PCR, strains of any of these five Salmonella serovars could be detected by a chromogenic biochip deployed with DNA probes specific to these five Salmonella serovars. In comparison with the multiplex PCR methods, the biochip assay could improve the detection limit of each of the Salmonella serovars from N × 10³ cfu/mL to N × 10² cfu/mL sample in either the pure culture or the chicken meat samples. With an 8-hour enrichment step, the detection limit could reach up to N × 10⁰ cfu/mL.     

荧光定量PCR和外周血白细胞pp65抗原血症实验对肾移植术后巨细胞病毒感染的检测

目的 探讨肾移植术后3个月巨细胞病毒(CMV)的感染状况，比较荧光定量PCR和外周血白细胞pp65抗原血症实验两种方法对肾移植术后巨细胞病毒感染的检测情况和使用价值。方法 分别用荧光定量PCR、外周血白细胞pp65抗原血症实验和ELISA法对我院2001年1月～2002年12月56例肾移植患肾移植术后3个月的外周血进行巨细胞病毒的检测。结果 56例肾移植患中CMVpp56抗原血症阳性9例(16．1％)，PCR阳性11例(19．6％)，12例(21．4％)诊断为CMV感染，其中7例为症状性感染，5例为无症状性感染。荧光定量PCR和外周血白细胞pp65抗原血症实验的一致性为92％，阳性符合率67％，阴性符合率92％。CMVpp65抗原、CMV DNA PCR、CMV—IgM的敏感性、特异性分别为72％、92％；100％、92％；43％、88％。结论 荧光定量PCR和外周血白细胞pp65抗原血症实验的联合应用，对监测CMV活动性感染、临床疗效及预后更加客观、准确。     

复合PCR-膜芯片技术对结核分枝杆菌链霉素耐药性的快速检测

目的　应用复合聚合酶链反应 (复合 PCR) -膜芯片技术快速检测结核分枝杆菌对链霉素 ( SM)的耐药性。方法　设计与合成用于检测结核分枝杆菌耐 SM基因 rps L和 rrs的寡核苷酸探针制作膜芯片 ,与结核分枝杆菌分离株生物素标记的 rps L和 rrs基因复合 PCR产物进行反向斑点杂交 ,并与 PCR-单链构象多态性 ( PCR- SSCP)和 PCR-直接测序 ( PCR- DS)结果比较。结果　 5 2株结核分枝杆菌临床分离株中 ,9株敏感株rps L和 rrs基因的 SSCP图谱、膜芯片杂交结果与标准株完全相同 ;4 3株耐 SM菌株中 ,33株存在 rps L 基因4 3位密码子 AAG→ AGG突变 ,5株有 rrs基因 5 13位 A→C突变 ,1株有 rrs基因 5 13位 A→ T突变 ,突变率为 90 .7%。结论　膜芯片技术检测结核分枝杆菌耐 SM基因型灵敏度高、特异性强、简便、快速 ,可用于临床耐药性检测     

Managing invasive aspergillosis in haematological patients in the era of resistance polymerase chain reaction and increasing triazole resistance: A modelling study of different strategies

Objectives

Triazole resistance in Aspergillus spp. is emerging and complicates prophylaxis and treatment of invasive aspergillosis (IA) worldwide. New polymerase chain reaction (PCR) tests on broncho-alveolar lavage (BAL) fluid allow for detection of triazole resistance at a genetic level, which has opened up new possibilities for targeted therapy. In the absence of clinical trials, a modelling study delivers estimates of the added value of resistance detection with PCR, and which empiric therapy would be optimal when local resistance rates are known.

聚合酶链反应检测肺孢子菌的实验研究

目的探讨应用改良传统三步聚合酶链反应(PCR)方法检测肺孢子菌DNA的意义。方法选择Wistar大鼠40只,随机分成实验组和对照组各20只。实验组每周2次皮下注射地塞米松,诱导产生肺孢子菌;对照组注射等剂量的生理盐水。8周后,收集大鼠肺组织和支气管肺泡灌洗液(BALF),分别用三步法与两步法PCR技术检测肺孢子菌DNA,并与Giemsa染色法比较。结果 PCR方法检测肺泡灌洗液中肺孢子菌DNA的方法敏感性(70%)明显高于常规染色法(30%)(P<0.05),且敏感度93%、特异度100%、阳性预测值100%、阴性预测值83%。实验组中PCR检测肺组织和支气管肺泡灌洗液的肺孢子菌DNA阴性者,Giemsa病原染色法亦为阴性。实验组大鼠的肺组织与支气管肺泡灌洗液分别行传统三步法与二步法PCR检测,2种检测方法阳性率相同,分别为80%和70%,差异无统计学意义(P>0.05)。对照组大鼠各种方法检测均为阴性。结论两步法PCR可作为早期诊断肺孢子菌肺炎(PCP)的方法,可用于BALF中检测肺孢子菌DNA,其敏感度、特异度、阳性预测值和阴性预测值均很高,易于临床推广应用。     

Development of a miniaturised microarray-based assay for the rapid identification of antimicrobial resistance genes in Gram-negative bacteria

We describe the development of a miniaturised microarray for the detection of antimicrobial resistance genes in Gram-negative bacteria. Included on the array are genes encoding resistance to aminoglycosides, trimethoprim, sulphonamides, tetracyclines and β-lactams, including extended-spectrum β-lactamases. Validation of the array with control strains demonstrated a 99% correlation between polymerase chain reaction and array results. There was also good correlation between phenotypic and genotypic results for a large panel of Escherichia coli and Salmonella isolates. Some differences were also seen in the number and type of resistance genes harboured by E. coli and Salmonella strains. The array provides an effective, fast and simple method for detection of resistance genes in clinical isolates suitable for use in diagnostic laboratories, which in future will help to understand the epidemiology of isolates and to detect gene linkage in bacterial populations.     

流式微球分析技术联合检测血清MMP-9、MPO CD40L和t-PA的方法学建立及评价

目的 建立流式微球分析技术联合检测人血清中基质金属蛋白酶-9 (MMP-9)、髓过氧化物酶(MPO)、CD40配体(CD40L)、血浆纤溶酶原激活物(t-PA)的方法并对其进行系统性评价.方法 分别将四种选择好一定浓度的捕获抗体(MMP-9、MPO、CD40L和t-PA鼠抗人单克隆抗体)包被在四种已激活的不同荧光强度编码的羧基化聚苯乙烯微球上,用棋盘法对试验条件进行优化选择,并应用CLSI的有关规则进行方法学评价.结果 反应体系中四种鼠抗人单克隆抗体最佳加入量为10 μg,最佳生物素标记抗体浓度为1∶4000倍稀释,最佳反应时间为2h,亲和素最适孵育时间为1h.MMP-9线性范围是0.20～333.33 ng/mL,批内变异系数为4.60％～8.80％,批间变异系数为8.80％～9.60％,准确度相对偏倚为2.80％～3.18％,回收率是94.8～102.50％,灵敏度为0.20 ng/mL;MPO线性范围是0.26～111.11ng/mL,批内变异系数为5.90％～7.70％,批间变异系数为9.10％～11.40％,准确度相对偏倚为1.44％～4.12％,回收率是97.8～103.2％,灵敏度为0.26 ng/mL;CD40L线性范围是0.32～111.11g/mL,批内变异系数为5.40％～6.50％,批间变异系数为8.90％～12.40％,准确度相对偏倚为2.72％～5.95％,回收率是97.20～105.30％,灵敏度为0.32 ng/mL;t-PA线性范围是1.21～111.11 ng/mL,批内变异系数为2.20％～2.90％,批间变异系数为6.30％～12.20％,准确度相对偏倚为1.23％～4.60％,回收率是97.20～101.30％,灵敏度为1.21 ng/mL.高浓度的甘油三酯、胆固醇和胆红素对四种因子有一定的干扰率,低浓度的甘油三酯、胆固醇和胆红素对三种因子干扰较小.分别与ELISA方法比较无显著差异.结论 自建的MMP-9、MPO、CD40L和t-PA1流式微球联合检测技术,可拓展流式细胞分析技术,值得临床推广使用.     

Development and validation of a new assay for assessing clot integrity

IntroductionResearch and routine laboratory assessment of clot integrity can be time consuming, expensive, and cannot be batched as it is generally performed in real time. To address these issues, we developed and validated a micro-titre based assay to quantify thrombogenesis and fibrinolysis, the purpose being to assess patients at risk of cardiovascular events by virtue of hypercoagulability. In further validation, thrombogenesis results were compared to similar indices from the thrombelastograph (TEG).MethodsOur assay determines three indices of thrombogenesis (lag time to the start of thrombus formation (LT), rate of clot formation (RCF), and maximum clot density (MCD)) and two of fibrinolysis (rate of clot dissolution (RCD) and time for 50% of the clot to lyse (T50)). Plasma was tested fresh and again after being frozen at − 70 °C. Some samples were tested immediately, others after being left at room temperature for up to 24 h.ResultsThe intra-assay coefficients of variation (CVs) of the three thrombogenesis measures (LT, RCF, MCD) and two fibrinolysis measures (RCD, T50) varied between 2.7 and 12.0% in fresh plasma and between 1.3% and 10.8% in frozen plasma respectively. Similarly, the inter-assay coefficients of variation of the thrombogenesis and fibrinolysis measures were 4.9–10.8% in fresh plasma and 2.2–6.5% in frozen plasma respectively. TEG assays intra- and inter assay CVs were around 25%. There were no significant differences in all plate assay indices up to 6 h at room temperature. Certain plate assay thrombogenesis data were comparable to TEG indices after analysis by Pearson's correlation. The reagent processing cost per sample is £15 for TEG and £2 for the plate assays.ConclusionOur micro-titre based assay assessing plasma thrombogenesis and fibrinolysis has good intra- and inter-assay CVs, can assess plasma up to 6 h after venepuncture, is more efficient (in terms of throughput) and is more economical than that of the TEG.     

Development and validation of a quantitative assay for raloxifene by capillary electrophoresis

The migration behavior of raloxifene was investigated by capillary electrophoresis (CE). The influence of different parameters (nature and concentration of the running buffer, pH and applied voltage) on migration time, peak symmetry and efficiency was systematically investigated. A buffer consisting of 20 mM acetate buffer of pH 4.5 was found to provide a very efficient and stable electrophoretic system for the analysis of raloxifene. The optimized method was validated with respect to precision, linearity, limits of detection and quantification, accuracy and robustness. The applicability of the assay was demonstrated by analyzing this drug in human plasma and pharmaceutical preparations.     

Optimization of differential display polymerase chain reaction as a bioindicator for the cladoceran Daphnia magna

Research on toxicant-responsive genes is providing new and important bioindicators for environmental biologists. Identifying genes whose expression is modulated by toxicant exposure provides important clues into the mechanisms underlying toxicity. In addition, toxicant-responsive genes can be developed as molecular end points that are likely to be sensitive tools for environmental assessment. Differential display polymerase chain reaction (ddPCR) is a useful approach for screening and analyzing the expression of genes. A ddPCR protocol was optimized to investigate gene expression in the cladoceran Daphnia magna. The modified protocol requires submicrogram quantities of total RNA (from <10 animals) and utilizes a sensitive fluorescent tagging system. By reverse-transcribing total RNA with arbitrary 18-nucleotide primers and PCR-amplifying the cDNA using the same arbitrary primers under low-stringency conditions, reproducible and consistent ddPCR profiles were generated. Minimal variability was introduced by reaction differences or biological variability. A trial stress (starvation) was found to generate modest differences in the ddPCR profiles. This technique promises to significantly advance knowledge regarding gene expression during toxicant insult. Furthermore, this represents the first step in the development of a novel gene fingerprinting technique that can be applied to any compound and organism of interest.     

重组酶介导扩增技术与传统聚合酶链反应技术在甲状腺癌DNA甲基化检测中的应用比较

目的 建立重组酶介导的核酸扩增(RAA)技术特异性检测DNA甲基化的新方法并与传统的DNA甲基化特异性PCR(MSP)方法进行比较.方法 选取OXTR基因作为目的基因,提取样品外周血基因组DNA,经亚硫酸氢盐修饰后分别以MSP和RAA技术进行特异性检测DNA甲基化实验.结果 2种技术皆能扩增出OXTR非甲基化条带,而RAA技术成功扩增OXTR甲基化条带.结论 RAA是一种新型的等温体外核酸扩增技术,实现了在37℃恒温下的核酸快速扩增,可成为替代MSP乃至其他PCR实验的新方法.     

Development and validation of an assay for iodide in serum using ion chromatography with pulsed amperometric detection

We developed and validated an ion chromatography method to assay iodide in serum sampled from rats and rabbits that had been exposed to iodomethane.

Iodomethane is of interest because it is a volatile liquid pre-plant soil crop protection fumigant that has been proposed as a non-ozone-depleting alternative to methyl bromide. Serum was prepared from whole blood collected on wet ice at the time of sacrifice and kept frozen at less than ?65°C. For analysis, serum samples were thawed unassisted at ambient temperature. Proteins were separated from the serum samples by ultrafiltration. A 100-μl filtered serum sample was then injected into the ion chromatograph without additional sample preparation. Iodide was separated in <20 min by anion-exchange chromatography using a 25-mM nitric acid eluent. The analyte of interest was detected by pulsed amperometry using a silver working electrode. The method showed linear response over the concentration range of 100 to 5000 ng/ml iodide (r²?>?.998) with a lower limit of quantitation of 100 ng/ml iodide. The accuracy of the procedure, determined by spiked recovery measurements at 100 ng/ml iodide, was between 90 and 110%. A method detection limit of 20 ng/ml for iodide in serum samples was demonstrated using the method of standard additions.     

Development and validation of a stability-indicating high performance liquid chromatographic assay for benoxinate

Benoxinate is a local anaesthetic used for ophthalmic applications. The aim of this study was to develop a rapid and simple stability-indicating method for the determination of benoxinate formulated for ophthalmic use, evaluate its long-term stability and identify its major degradation product. Benoxinate was eluted on a 10 microm Spherisorb phenyl column, 250 x 3.2 mm, with a mobile phase consisting of acetonitrile-buffer (pH 3.5) (35:65, v/v), pumped at 0.8 ml min(-1) flow rate. The buffer was composed of sodium dihydrogen phosphate (50 mM), sodium hydrogen sulfate (2.5 mM) and 1-heptanesulfonic acid sodium salt (5 mM). The analyte was quantified spectrophotometrically at 308 nm. The chromatograms of benoxinate formulations obtained by this method showed benoxinate (t = 4.5 min) well resolved from its degradation product (t = 2.3 min), which was separately identified by means of HPLC-MS as 4-amino-3-butoxybenzoic acid. The assay was demonstrated to have high accuracy, precision and linearity. The method was implemented in investigating the long-term stability of benoxinate 0.4% ophthalmic solutions. The method was found to be simple, quick and selective in determining benoxinate concentrations in fresh and aged preparations.     

Development and validation of a cell-based assay for the nuclear receptor retinoid-related orphan receptor gamma

The nuclear receptor retinoid-related orphan receptor gamma (RORγ) has become an attractive target for drug discovery due to its important role in the development and differentiation of Th17 cells, a subset of T cells that produce interleukin-17 and are involved in the pathogenesis of human inflammatory and autoimmune diseases. To facilitate the drug discovery efforts in this area, we have developed a cellular assay for screening for RORγ inverse agonists. We stably engineered a tetracycline-inducible Gal4 DNA-binding domain/RORγ ligand-binding domain fusion protein into an upstream activation sequence driven-beta-lactamase reporter gene cell line. Due to its constitutive activity, the induced Gal4-RORγ expression leads to increased reporter activity, which can be knocked down using RORγ ligand-binding domain-specific RNA interference oligos. Using this assay, we tested several recently reported ligands for RORγ and observed varying levels of partial inverse agonist activity at μM concentrations. Additionally, we screened a small library of biologically active compounds with this assay and demonstrated its robustness and usefulness in high-throughput screening and follow-up studies for this emerging drug target.     

噬菌体生物扩增法快速测定结核分枝杆菌对异烟肼和利福平的药物敏感性应用价值

目的探讨噬菌体生物扩增法（PhaB）快速测定结核分枝杆菌对异烟肼（INH）和利福平（褂甲）的药物敏感性在临床应用价值。方法选择初治肺结核病患者留痰后培养获得的结核分枝杆菌菌株69株和复治患者留痰后培养获得的结核分枝杆菌菌株98株。均经改良罗氏培养基培养并进行菌型鉴定,证实为结核分枝杆菌（MTB）。分别采用PhaB法和改良罗氏比例法检测其对INH和RFP的耐药性,将2种方法的结果进行敏感度、特异度和符合率比较。结果（1）初治结核分枝杆菌69株中,与改良罗氏比例法比较,PhaB法检测INH的敏感度、特异度和符合率分别为80％（4／5）、90．6％（58／64）和89．9％（62／69）;PhaB法检测趾11P的敏感度、特异度和符合率分别为100％（3／3）、95．5％（63／66）和95．7％（66／69）。（2）复治结核分枝杆菌98株中,与改良罗氏比例法比较,PhaB法检测INH的敏感度、特异度和符合率分别为89．7％（35／39）、88．1％（52／59）和88．7％（87／98）;PhaB法检测肿的敏感度、特异度和符合率分别为97．1％（34／35）、93．7％（59／63）和94．9％（93／98）。结论噬菌体生物扩增法同改良罗氏比例法比较有较高的敏感度、特异度和符合率,可快速、准确地检测结核分枝杆菌对INH和RFP的耐药性。