PCR-SSCP法检测结核分枝杆菌耐药性

目的：探讨耐多药结核分枝杆菌耐药基因突变与耐药性的关系以及聚合酶链反应-单链构象多态性分析(poly merase chain reaction-single strand cinfomlation polymorphism，PCR-SSCP)方法的临床应用价值。方法：用PCR-SSCP方法检测58株结核分枝杆菌临床分离株katG，rpoB，rpsL基因突变并与常规药敏试验检测结果进行对比。结果：经常规药敏试验检测，58株结核分枝杆菌临床分离株中共有41株耐药，其中，耐异烟肼(INH)为35株，高耐药株27株；耐利福平(RFP)为31株，高耐药株24株；耐链霉素(SM)有31株，高耐药株26株。同时耐3种药物的有21株(51．2％)，耐2种药物的14株(34．1％)，单耐药株6株(14．6％)．PCR-SSCP方法对58株临床分离株katG，rpoB，rpsL基因突变的检测率为40％(23／58)，45％(26／58)，38％(22／58)，其中检出3个基因同时突变的有13株(32％)，2种基因突变的12株(29％)，1种基因突变的有10株(23．8％)．常规药敏试验与PCR-SSCP法检出结核分枝杆菌同时耐3种药物的符合率为61．9％(13／21)，检出耐2种药物的符合率为85．70k，(12／14)，检出耐1种药物的符合率为50％(3／6)．高耐药株中突变率为80．5％(62／77)，低耐药株中突变率为60％(12／20)．结论：PCR-SS-CP方法对耐2种以上药物的结核杆菌检出率较高，且耐药基因突变率随着耐药浓度增高而增高。将PCR-SSCP法与药敏试验联合应用可互相弥补，已成为临床指导用药的好方法。     

Tau isoform expression in frontotemporal dementia without tau deposition

In many cases of sporadic frontotemporal dementia (FTD) and in FTD caused by tau mutations (FTDP-17) there is disruption of the normal splicing of tau leading to the aberrant expression of tau isoforms and neurodegeneration. This suggests a central role for tau in the pathogenesis of FTD. However, more than half the cases of sporadic FTD show no tau deposition. We question whether altered expression is also involved in the pathogenesis of tau-negative FTD. Real-time polymerase chain reaction was used to investigate tau isoform expression in tau-negative FTD and age-matched controls. There were no differences in total tau mRNA or 4R versus 3R isoform expression. Our study suggests that perturbed tau mRNA expression is unlikely to be involved in the pathogenesis of tau-negative FTD.     

高转移小鼠肺癌株细胞导入人基因组DNA后的转移表型抑制

目的 探讨从正常人细胞基因组ＤＮＡ中寻找、分离并鉴定肿瘤转移抑制基因或相应ＤＮＡ序列的新途径。方法 采用体内转移灶体外再培养再硬琼脂集落克隆化筛选，获体内９０％以上高转移率小鼠肺腺癌ＬＭ２细胞株；使用磷酸钙共沉淀ＤＮＡ转染技术，将正常细胞人基因组ＤＮＡ随机片段，导入高转移小鼠肺癌细胞株ＬＭ２后，使用有限稀释法克隆化其中形态扁平的回复突变株。为证实细胞确实含有外源人ＤＮＡ序列，设计人特异性Ａｌｕ引物     

Rapid determination of trisomy 18 parental origin using fluorescent PCR and small tandem repeat markers: case reports

Trisomy 18 is the second most common genetic defect after trisomy 21, almost 90% of which are due to additional chromosome from the mother. The parental origin of the additional chromosome can, if required, be determined by two methods: karyotyping, which takes several weeks; or, more recently, by polymerase chain reaction (PCR) which is often problematic. Fluorescent PCR of small tandem repeats (STRs) can determine the parental origin in the majority of cases within 5 h. Although the incidence of paternal origin is known for both trisomy 21 and trisomy 18, this technique can rapidly determine the parental origin in cases where there is insufficient samples to perform conventional tests. Determining parental origin by these methods may also have clinical significance in the diagnosis of chromosomal translocations or in the diagnosis of genetic disease using linkage analysis.     

P53基因突变与宫颈癌关系的研究

目的：通过对宫颈癌Ｐ５３基因７－８外显子突变的研究，探讨该基因的突变与宫颈癌的发生、发展之间的关系。方法：本文运用聚合酶链式反应（ＰＣＲ）方法，对宫颈癌组织Ｐ５３的７－８外显子是突变进行了试验，并与非肿瘤的慢性宫颈炎（宫颈糜烂、宫颈息肉）组织作了对照。结果：１０例宫颈癌标本中有７例出现了Ｐ５３７－８外显子的突变，阳性率高；而８例作为对照的宫颈炎标本仅有１例出现可疑的阳性结果。结果：试验结果说明，宫     

PCR检测结核分枝杆菌DNA中不同细菌裂解方法结果观察

目的：寻找适合于临床ＰＣＲ检测结核杆菌ＤＮＡ简单、快速、有效、经济的细菌裂解方法。方法：采用１１种细菌裂解剂对相同数量的结核分枝杆菌进行裂解，裂解上清液直接用于ＰＣＲ扩增，结果：１％ＴｒｉｔｏｎＸ－１００，１％ＮＰ４０，１％Ｔｅｗｅｅｎ２０、和１％ＯＰ四种裂解剂的裂解液可直接扩增出结核分枝杆菌ＤＮＡ；ＳＤＳ，ＮａＯＨ，十二烷基肌酸钠等裂解剂的裂解液直接用于ＰＣＲ扩增均为阴性。结论：１％的Ｔｒｉｔｏｎｘ－１００，ＮＰ４０、Ｔｅｗｅｅｎ２０和乳化剂ＯＰ裂解细菌效果好，又不抑制ＰＣＲ反应，适合于作为临床ＰＣＲ检测结核杆菌的裂解剂。     

聚合酶链反应在鼠疫菌检测中的应用 研究

本文采用聚合酶链反应（ＰＣＲ）技术，通过扩增鼠疫菌９．５ｋｂ质粒ｐｌａ基础上一个４７８ｂｌ片段，用于鼠疫菌检测，被试的４５株鼠疫菌扩增产物经琼脂糖凝胶电泳分析均呈现单一ＤＮＡ带，其分子量大小与预期结果符合。而假结核菌和一株缺６ＭＤ质粒鼠疫菌未见扩增带，洽部实验可在４ｈ内完成。本法具有快速、特异、敏感等优点，可用于不同生态型鼠疫菌的快速诊断和流行病学研究．     

Using the polymerase chain reaction to maintain DNA probe inventories in clinical and diagnostic laboratories

Clinical and diagnostic DNA laboratories must maintain a large inventory of DNA probes for use in hybridization studies. The preparation of plasmid DNA and isolation of DNA fragments for use as probes in both expensive and time consuming. We present here a rapid and relatively inexpensive method of producing large amounts of DNA fragments from stocks, using the polymerase chain reaction (PCR). Our experience over the past year using this technique has been very positive and we believe many laboratories could benefit by employing such a labor-saving approach to maintaining DNA probes. The technique uses the bacteriophage M13 DNA sequencing primers to amplify cloned inserts contained in commonly used plasmid vectors. As examples, we illustrate the use of DNA produced in this manner as probes for linkage analysis of the fragile X syndrome and for detection of deletions in the Duchenne muscular dystrophy gene. We have also found that at least two probes can be amplified in the same PCR reaction, allowing the detection of two different restriction fragment length polymorphisms (RFLP) simultaneously. It should be possible for laboratories to devise strategies particular to their individual needs using more than one DNA probe produced in the same PCR reaction to detect RFLP's. Such strategies would need only to consider that the predicted alleles of the multiple polymorphisms do not migrate to the same position during electrophoresis. Stocks of single or multiple probes produced by the PCR could then be maintained for more rapid Southern analyses.