Typing ofLegionella pneumophilaserogroup 1 isolates by degenerate (D-)RAPD fingerprinting

A new method to identify clonal strains of pathogenic bacteria has been developed recently in this laboratory. The method utilizes degenerate random amplified polymorphic DNA primers (D-RAPD) to amplify random fragments in crude bacterial lysates, generating reproducible DNA banding profiles or fingerprints. We use this method to type outbreak and non-outbreak isolates ofLegionella pneumophilaserogroup 1 from four hospitals near to, and affiliated with the University of Pittsburgh Medical Center. Patient isolates from a large outbreak, and nearly half of the contemporaneous environmental isolates showed the same DNA profile. Other isolates derived from non-outbreak patients showed easily distinguishable profiles. OtherLegionellaisolates collected between 1984 and 1994 were also analysed by this method. Our studies demonstrate that four strains were common among patient and environmental isolates at the four hospitals. These strains were also found to be different from a limited number of isolates from outside the Pittsburgh area. Because of its speed, simplicity and powerful discriminating ability, we believe that the D-RAPD approach provides epidemiologists and hospital infection control teams with a powerful tool in their efforts in analysing and terminating infection outbreaks.     

应用PCR-RFLP进行申克孢子丝菌的分子生物学鉴定

目的　探索一种简单、快速的申克孢子丝菌的鉴定方法。方法　应用真菌通用引物ITS1和ITS4对来源于不同地区及不同临床型别孢子丝菌病的 2 8株申克孢子丝菌以及 9种其他临床上重要的真菌进行PCR扩增 ,利用限制性内切酶HaeⅢ对PCR产物进行酶切分析鉴定。结果　所有 2 8株申克孢子丝菌和其他 9种真菌均扩增出一条约 3 5 0bp的片段 ,其中 2 8株申克孢子丝菌RFLP带型一致 ,与 9种其他临床上重要的真菌RFLP带型差异较明显。 结论　PCR RFLP可以为建立一种简单、快速鉴定申克孢子丝菌的方法提供依据。     

双重式PCR检测鼠疫流行现场动物脏器的结果分析

目的探讨双重式聚合酶链反应(Pla-FI-PCR)技术在鼠疫流行现场检测动物脏器的应用。方法应用双重式PCR技术，采用简单的加热法处理模板，对罗平县的50份动物脏器进行检测。结果检出阳性22份，阳性率为44％，其中活鼠脏器阳性11份。结论提示双重式PCR检测活鼠材料作为早期发现疫情具有一定的应用价值。     

PCR as a rapid and sensitive tool in the diagnosis of human and canine leishmaniasis using Leishmania donovani s.l.-specific kinetoplastid primers

This study was performed in order to test the efficacy of a new polymerase chain reaction (PCR) assay for the diagnosis of both human and canine leishmaniasis caused by Leishmania infantum. The new primers were developed on the basis of a complete DNA sequence of the L. infantum kinetoplast minicircle. Specificity and sensitivity were evaluated by testing bone marrow spots on filter paper and skin biopsy samples, and the PCR results were compared to data from in vitro cultures. Leishmania strains from different foci, as well as other trypanosomatids and opportunistic pathogenic micro-organisms, were also included in this study. The results show that the primers are highly specific, detecting only L. donovani s.l. DNA, and sensitive for the detection of parasite DNA in biological samples from three different geographical regions of Portugal (north, centre and south) and from Brazil.     

致病性大肠埃希菌O2、O（78）及融合双价弱毒菌株O（2,78）（Chl^rNor^r）ompA基因的克隆及序列分析

目的 应用PCR扩增大肠埃希菌O2、O78及融合双价弱毒菌株O2,78的外膜蛋白A（ompA）基因,并进行克隆。方法 根据GenBank中人源大肠埃希菌K-12的ompA核苷酸序列设计特异引物,应用PCR对大肠埃希菌O2、O78及融合双价弱毒菌株O2,78的ompA基因进行体外扩增、克隆和序列分析。结果 O2、O78和O2,78经PCR获得的ompA基因片段大小为1 041 bp,与理论值相符;经过克隆和测序分析,该基因的核苷酸序列均由2 271 nt组成,编码1个由346个氨基酸组成的前外膜蛋白A,三菌株ompA基因核苷酸序列与GenBank提供的已知基因序列比较,同源性均为100%。结论 本研究成功克隆了大肠埃希菌ompA基因全长。     

HLA-DQA1、-DRB1等位基因与子宫内膜异位症和子宫腺肌病的比较性研究

目的 从免疫遗传学角度比较子宫内膜异位症和子宫腺肌症的异同。方法 采用顺序特异引物聚合酶链反应技术检测51例子宫内膜异位症和45例子宫腺肌病患者的HLA－DQA1和HLA－DRB1等位基因频率，并与44名正常人比较。结果 两患者组HLA－DQA1＊0301等位基因频率（8.8%,5.6%）均明显低于正常对照组，差异有显著性（Pc=0.00,Pc=0.00），而两患者组的HLA－DQA1＊0.0401等位基因频率（7.8％,10.0%）均明显高于对照组，差异有显著性（Pc=0.03,Pc=0.01）；两患者组之间HLA－DQA1、－DRB1各等位基因频率比较，差异无显著性。结论 子宫内膜异位症及子宫腺肌病均与HLA－DQA1＊0301、＊0401相关联，从HLA－DQA1、－DRB1角度分析，子宫内膜异位症与子宫腺肌病的发病机理可能有共同之处。     

荧光标记复合扩增短串联重复序列基因分析骨髓移植物的植入

目的 为了准确地识别骨髓移植物的植入状态,探讨PCR扩增短串联重复序列（short tandem repeat,RCR－STR）在亲缘或无关供者骨髓移植的预后及白血病复发中的预警作用。方法 建立荧光标记PCR－STR等位基因分析技术,采用单克隆磁珠提取DNA,四色荧光标记,于移植前、移植后7天－6个月不等,采集供、受者血液（2例回顾性研究患者刮取口腔粘膜脱落细胞作为术前样本）DNA作PCR－STR分析。结果 ①12例患者骨髓移植后10例为完全供者型,其中同胞损髓8例,HLA全相合77例,半相合1例;无关供者损髓1例,HLA全相合,母亲供髓1例,HLA-Ⅰ全相合,HLA－Ⅱ半相合。10例受者术后出现Ⅰ度移植物抗宿主病（GVHD）,STR均完全和持续表达供者基因型,追求观察3－25个月,预后良好。②12例中1例由嵌合型转变为完全供者型,系同胞损髓,HLA－Ⅰ半相合,HLA－Ⅱ全相合;术后第30天PCR－STR表达供、受者双方基因型,第60天完全转变为供者基因型,而自身的基因在外周血中消失,预后良好。③12例中1例为持续未植入,HLA半相合同胞捐髓,术后虽然有血液学和临床情况的改善,但移植后7,14,21天STR分析始终仅显示受者基因型,移植后4个月死亡。结论 基于分子水平的移位点PCR－STR分析是骨髓移植后供者植入的精确标志。研究表明,PCR－STR植入分析的准确性优于任何传统技术,对移植效果有预警作用。     

随机引物引导的乙型肝炎病毒DNA探针标记和重复杂交

随机引物引导的探针标记足一种比切中移位更为有效的探针标记方法,作者应用这种方法制备~(32)P标记的乙型肝炎病毒(HBV)DNA探针。经液闪测定,探什比放射性为lxl0~(9)cpm/ug,(32)P掺入率为71.43％,均比切口移位有关参数上限高出数倍。将这种探针用于尼龙膜载样杂交,在每100cm~(2)的样膜所加探针放射性强度为5 x10~(6)cpm、浓度为20ug/L条件下,放射自显影24小时即可出示清晰结果。并且检出HBV DNA灵敏度达0.1Pg,检测HBSAg和HBCAg双阳性血清,HBVDNA阳性率达87％(26/30)。用这种方法还制备地高辛素标记的HBV DNA探针,并在探针浓度为20 ug/L条件下,对~(32)p探针杂交过的样膜重复杂交。结束检出HBV DNA灵敏度为0.05 Pg,检测HBsAg和HBeAg双阳性血清,HBV DNA阳性率为73％(22/30)。上述结果表明随机引物引导标记可用于制备高比放同位素探针和高敏感性非同位索探针。前者对研究微量基因必不可少,后者对基层单位常规开展检测非常重要。     

FcγRIIIB polymorphism: evidence that NA1/NA2 and SH are located in two closely linked loci and that the SH allele is linked to the NA1 allele in the Danish population

BACKGROUND: The neutrophil-specific antigens NA1, NA2, and SH are well-recognized allotypic forms of FcgammaRIIIB. Individuals carrying all three FcgammaRIIIB genes were recently described. STUDY DESIGN AND METHODS: A Danish population (n = 200) was typed for NA1, NA2, and SH by polymerase chain reaction with sequence-specific primers (PCR-SSP). Twelve individuals with three FcgammaRIIIB genes were further genotyped by PCR-based restriction fragment length polymorphism and by DNA sequencing. Family studies were performed on three individuals who carry three FcgammaRIIIB genes. RESULTS: The gene frequencies for NA1, NA2, and SH were 0.365, 0.635, and 0.030, respectively. In eight individuals (4%), all three FcgammaRIIIB genes were identified. All 12 SH+ individuals were NA1+. CONCLUSION: The NA1, NA2, and SH gene frequencies observed in Danes are similar to those in other white populations. The distribution of FcgammaFIIIB genotypes in the Danish population strongly indicates that the NA and the SH systems are located in two closely linked loci and that SH is closely linked to NA1. Finally, a new PCR-SSP was developed to distinguish NA2 from SH.     

An in-vitro investigation into the use of a single component self-etching primer adhesive system for orthodontic bonding: a pilot study

Abstract

Objective: This pilot study assessed force to debond (N); time, and site of bond failure of a single component self-etching primer (SEP) and adhesive system, Ideal 1 (GAC International Inc., USA) and compared it with the conventional acid etch and rinse regimen using 37% o-phosphoric acid solution and either Transbond^TM XT (3M Unitek) or Ideal 1 adhesive.

Design: In vitro laboratory study

Setting: Bristol Dental Hospital, UK. Sept 2003-Sept 2004

Material and Methods: Nine groups of 20 premolars were bonded using metal orthodontic brackets using three protocols: (1) 37% o-phosphoric acid etch and Transbond^TM XT adhesive; (2) 37% o-phosphoric acid and Ideal 1 adhesive; (3) Ideal 1 SEP and Ideal 1 adhesive. Force to debond and locus of bond failure were determined at three time intervals.

Results: Enamel pre-treatment prior to bonding, namely SEP versus conventional etching had no significant effect on the median force to debond with the Ideal 1 adhesive. Similarly, when the enamel was conventionally etched, the adhesive type, namely Ideal 1 or Transbond^TM XT, had no significant effect on the measured force to debond. However, there appeared to be differences in the locus of bond failure: failure predominated at the enamel/adhesive interface for the Transbond^TM XT conventional etch group and at adhesive/bracket interface for the Ideal 1 SEP and adhesive group and the Ideal 1 adhesive conventional etch group.

Conclusion: These results suggested that the complete Ideal 1 SEP and adhesive system might be successful in vivo leading therefore to a clinical trial. However, implications for clean up time are discussed and improvements to in vitro study designs are advised.