Differentiation of Helicobacter pylori isolates by polymerase chain reaction—restriction fragment length polymorphism

Objective: To investigate the association between the diversity of urease gene and urease activity of clinical isolates of Helicobacter pylori (H. pylori). Methods: Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of urease gene and rapid urease activity test were used to study the urease activity of different clinical isolates of H. pylori. Results: H. pylori clinical isolates were divided into 4 types according to their PCR-RFLP results of urease gene and urease activity. Type Ⅰ , possessing strong urease activity (0. 11) and presented 1 fragment of 1. 7 kb by PCR-RFLP, had close relations with gastric ulcer; type Ⅱ , with the weakest urease activity (0. 07) and 2 fragments (1. 3 and 0. 4 kb respectively) , was associated with duodenal bulb ulcer; type Ⅲ , with the strongest urease activity (0. 12) and 2 fragments (0. 4 and 0. 17 kb) with or without 1 fragment (0. 23 or 0. 37 kb) , was responsible for gastritis; type Ⅳ , with weak urease activity (0. 09) and 2 fragments     

Helicobacter pylori

Helicobacter pylori infection is a major cause of peptic ulcer disease, and its detection and eradication are now an important part of gastroenterology. Effective regimes are available which will eliminate the organism in about 90% of cases in developed countries.     

幽门螺杆菌cagA基因片段原核表达载体的构建及其cagA基因和CagA蛋白及感染者血清抗体的检测

目的:构建幽门螺杆菌(Helicobacter pylori,Hp)cagA基因片段的原核表达系统,建立ELISA检测CagA及其抗体,了解表达CagA的Hp菌株(CagA Hp)感染与所致疾病种类的关系.方法:从快速尿素酶试验阳性的156例患者胃黏膜活检标本中分离Hp.采用PCR检测109株Hp cagA基因,并从临床菌株Y06中扩增2 148 bp的cagA基因片段(cagA1).构建cagA1原核表达系统,用SDS-PAGE检查目的重组蛋白(rCagA1)的表达情况,用Western blot和免疫双扩散试验鉴定rCagA1的免疫反应性和抗原性.建立ELISA,检测109株Hp CagA表达和相应患者血清中CagA抗体.分析CagA Hp感染与胃炎和消化性溃疡的关系.结果:80.8%胃黏膜活检标本中分离出Hp(126/156),97.2%的Hp菌株(106/109)cagA基因阳性.与文献报道比较,所克隆的cagA1片段核苷酸和氨基酸序列同源性分别为94.83%和93.30%.所构建的原核表达系统表达的rCagA1量约为细菌总蛋白的30.0%.rCagA1能与Hp全菌抗体发生结合反应,免疫家兔产生双扩散效价为1∶4的抗体.92.6%菌株(101/109)可表达CagA,88.1% 患者(96/109)血清CagA抗体阳性.消化性溃疡标本中CagA Hp菌株分离阳性率(97.9%)高于胃炎标本(88.5%),但无统计学差异(χ2=3.48,P>0.05).结论:本实验构建的原核表达系统表达的rCagA1有良好的免疫反应性和抗原性,建立的ELISA可用于Hp CagA及其抗体的检测,分离的Hp菌株cagA基因携带率和CagA表达率均很高.消化性溃疡和胃炎与其感染的Hp是否表达CagA无明显关系.     

Transmission of Helicobacter pylori

Helicobacter pylori is found predominantly in human gastric mucosa. Transfer of the bacterium remains an open topic, but it is likely that infection is usually acquired at a young age, particularly where lower socio-economic conditions prevail. Transmission via an external source such as water supply is a possibility but, in general, infection is probably passed from person to person. Arguments for and against faecal-oral, oral-oral and gastric-oral transmission have been presented, but the dominance of one of these routes is still to be determined.     

Non-invasive testing for Helicobacter pylori

Confirmed and potential benefits of eradicating Helicobacter pylori have led to the development of a range of diagnostic tests. As well as techniques using biopsy tissue obtained during endoscopy, a number of non-invasive tests are now available. These may be appropriate for pre-endoscopy screening of younger dyspeptics, for use in research, particularly epidemiological surveys, to confirm successful eradication after treatment, and possibly in the future for screening in asymptomatic populations. Serology requiring laboratory analysis is likely to be the least expensive option, particularly suitable for testing large numbers, while urea breath tests should yield the most accurate results and are appropriate for confirming successful eradication since only current infection is detected. The performance of near-patient tests can lack consistency, but these may be useful for small numbers and where other non-invasive testing is unavailable. Tests should be used with an awareness of their potential limitations in terms of accuracy.


     

人类线粒体tRNAs基因在CagA阳性Hp培养滤液诱导转化的胃上皮细胞中表达

目的 研究CagA阳性Hp培养滤液对人胃粘膜上皮细胞（GES－1）作用的机制。方法 将CagA阳性Hp培养滤液诱导恶性转化的GES－1细胞与CagA阴性Hp培养滤液处理的GES－1细胞进行mRNA差异显示,以寻找Hp致胃癌发病的相关基因。结果 mRNA差异显示片断之一命名为PFN2,仅在Hp(CagA^ )培养滤液处理的GES－1细胞中表达,斑点杂交结果与之一致。与Gene Bank资料序列同源性比较分析提示PFN2与人类线粒体tRNAs同源性100％,即为人类线粒体tRNAs基因的一部分。结论 人类线粒体tRNAs基因可能参与了Hp的CagA诱导的胃上皮细胞恶性转化过程。     

U_（937）细胞c──fos癌基因限制性多态性分析

本文分别用ＥｃｏＲＩ、ＨｉｎｄⅢ、ＢａｍＨⅠ、ＨａｅⅢ限制性内切酶对Ｕ９３７细胞基因组ＤＮＡ和正常人基因组ＤＮＡ进行Ｓｏｕｔｈｅｒｎｂｌｏｔ分析，结果表明Ｕ９３７细胞存在Ｃ──ｆｏｓ基因限制性多态性改变，并伴随着基因扩增。     

幽门螺杆菌cagA基因全长克隆及序列分析

目的探索扩增cagA基因全长的PCR方法,克隆中国2株胃癌幽门螺杆菌(Helicobacter pylori,Hp)分离株和1株十二指肠溃疡分离株及国际标准株SS1的cagA基因,初步探讨cagA序列和磷酸化位点变异及其临床意义.方法针对已知cagA基因两侧及cag致病岛右侧反转重复序列设计PCR引物,扩增cagA基因并克隆测序,分析已知cagA序列同源性及其酪氨酸磷酸化位点.结果3株中国Hp分离株cagA氨基酸序列的同源性约为94%(93.9%、94%、94.5%),并都有pY117/118/122和EPIYA-A、B、D 4个酪氨酸磷酸化位点.SS1株cagA与西方菌株同源性大于85%,而与中国菌株的同源性小于80%,具有pY117/118/122和EPIYA-A、B、C 4个酪氨酸磷酸化位点.结论建立的PCR方法可扩增cagA基因全长.CagA序列变异和磷酸化位点具有地区聚类特征,但与Hp感染临床结局无特殊关联.     

Carrier detection of Glanzmann's thrombasthenia by Taq I restriction fragment length polymorphism of GPIIIa gene]

Glanzmann's thrombasthenia (GT) is an autosomal recessive bleeding disorder in which platelets fail to aggregate in second hemostasis due to qualitative and/or quantitative defect in their GPIIb/IIIa complex. In the present study, both phenotypic and genotypic assays were performed by Western blot and Southern blot techniques in 13 members of 3 GT families. 2 GT carriers of 3 probable carriers whose clinical features and GPIIb/IIIa protein were essentially normal were determined by Taq I/5' GPIIIa RFLP. There were no major deletion or insertion in GPIIIa gene in 4 patients with GT. Thus, the genetic defects in these patients is most likely due to a small change or point mutation in the nucleotide sequence of GPIIIa coding region.     

幽门螺杆菌CagA基因的原核表达及抗原性测定

目的：合成胃癌相关幽门螺杆菌(Helicobacter pylori,H.pylori)的 CagA基因片段,建立原核表达系统,鉴定重组表达产物的抗原性。方法：选取前期研究确定的与胃癌相关的H.pylori CagA基因片段,优化设计并合成CagA基因,将合成的CagA基因从pUC57-CagA质粒中切出,用表达载体pET32a携带该基因转化宿主菌BL21(DE3),通过氨苄青霉素抗性筛选和菌落PCR挑选出阳性克隆pET32a-CagA;以IPTG诱导含pET32a-CagA的宿主菌表达融合蛋白,经SDS-PAGE凝胶电泳分析CagA蛋白表达情况,用Western印迹鉴定融合蛋白的抗原性。结果：设计并人工合成了CagA基因片段,序列测定结果显示,合成的CagA基因序列与设计的序列（AF289435）基本一致;成功构建pET32a-CagA原核表达质粒,对应蛋白序列与AAG09884同源性为100%;含pET32a-CagA的BL21(DE3)宿主菌经IPTG诱导后能表达CagA融合蛋白,经SDS-PAGE凝胶电泳分析结果表明,融合蛋白相对分子质量大小与预期一致(45 kD);Western印迹检测结果显示该融合蛋白可与抗H.pylori全菌抗体结合反应。结论：本实验构建的原核表达系统表达的CagA融合蛋白具有良好的抗原性,为临床胃癌相关H.pylori菌株的筛选和针对性治疗奠定了基础。     

Possible association of Helicobacter pylori infection with laryngeal cancer risk: an evidence-based meta-analysis

BACKGROUND: Infection with Helicobacter pylori (H. pylori) is a major cause of various gastric diseases and has been reported to play a role in the process of tumorigenesis and progression of gastric carcinoma. However, whether H. pylori infection increases susceptibilities to other cancers is not fully understood. Several studies have been devoted to the relationship between H. pylori infection and laryngeal cancer risk and have yielded conflicting results. In this study, we aimed to evaluate the possible association of H. pylori infection with laryngeal cancer risk. METHODS: The associated literature was acquired through deliberate searching and selected based on the established inclusion criteria for publications. Extracted data were further analyzed by a systematic meta-analysis. RESULTS: A total of 15 papers were identified. Of these, five case-control studies were selected. Laryngeal cancer risk for H. pylori infection was 2.03-fold (95% CI=1.28-3.23) (Z=3.00, p<0.01) compared with the controls. CONCLUSIONS: The pooled data suggest infection with H. pylori as a possible risk factor for laryngeal cancer.     

Evaluation of the one-minute ultra-rapid urease test for diagnosing Helicobacter pylori

To determine the diagnostic accuracy of the one-minute ultra-rapid urease test for diagnosing Helicobacter pylori infection, two biopsies were taken from both the gastric corpus and antrum from 1000 patients undergoing upper gastrointestinal endoscopy. All the biopsies were subjected to the one-minute ultra-rapid urease test before imprint smears were prepared from them. Thereafter, the biopsies were fixed in 10% formalin and histological sections were examined for the presence of H pylori by a pathologist who was not aware of the clinical details or the results of the urease test. The prevalence of H pylori in the gastric antrum and corpus was 86.7% and 53.3%, respectively. The sensitivity, specificity, positive and negative predictive value and the overall diagnostic accuracy of the ultra-rapid urease test to diagnose H pylori infection in the gastric antrum were 92%, 100%, 100%, 66%, and 93%, respectively. The corresponding figures for the gastric corpus were 83%, 100%, 100%, 85%, and 91%, respectively. It is concluded that the one-minute ultra-rapid urease test has a high sensitivity and specificity and may be used as a rapid and cheap method to diagnose H pylori infection.


     

应用错配PCR和限制性片段长度多态性分析技术检测HBV YMDD变异株

目的：建立简便易行的检测乙型肝炎病毒（HBV）多聚酶基因（P基因）上YMDD变异株的方法，评价运用拉米夫定治疗慢性乙型肝炎患对此变异的影响，方法：采用套式／错配聚合酶链反应（PCR）结合限制性片段长度多态性（RFLP）分析技术对108例治疗前HBV DNA（PCR）阳性正在拉米夫定治疗中的慢性乙型肝炎患者的HBV YMDD变异情况进行检测。结果：运用上述技术能有效区分HBV YMDD野生株和变异株，上述108例患者经拉米夫定治疗后，HBV DNA阴转者63例（58．3％），HBV YMDD野生株和变异株分别为23例（21．3％）和22例（20．4％），结论：建立的套式／错配PCR－RFLP分析技术可用于HBV YMDD变异株的临床监测，拉米夫定治疗慢性乙型肝炎患者可导致部分患者的HBV多聚酶基因上YMDD发生变异。     

耐拉米夫定乙肝病毒变异株的人工构建及其限制性片段长度多态性分析

目的　建立简便易行的筛检常见的耐拉米夫定乙肝病毒变异株的方法。方法通过PCR定向点突变 ,构建最常见的耐拉米夫定乙肝病毒变异株 (YMDD变异株 ) ,并建立相应的错配PCR结合限制性片段长度多态性分析 (RFLP)检测此变异株。结果PCR成功引入点突变 ,构建了YMDD变异株的克隆 ,同时错配PCR结合限制性片段长度多态性分析可有效区分YMDD变异株和HBV野毒株。结论采用PCR的方法可诱导定向点突变 ,错配PCR结合限制性片段长度多态性分析可用于筛检临床常见的耐拉米夫定乙肝病毒变异株 (YMDD变异株 ) ,为临床监测提供了一种很好的模式。     

多重PCR检测唾液标本中的幽门螺杆菌16S rRNA及cagA基因

目的 检测唾液标本幽门螺杆菌（Hp）的16S rRNA基因及cagA基因,了解消化道疾病患者口腔中Hp存在情况及致病情况。方法 利用生物学信息技术,设计Hp 16S rRNA、cagA基因特异性引物,建立检测Hp 16S rRNA、cagA基因的多重PCR方法;重组克隆质粒构建标准阳性对照品;收集156例消化道疾病患者的唾液标本,提取唾液标本中细菌DNA,应用建立的多重PCR方法,检测Hp 16S rRNA基因及cagA基因,并对结果进行分析。结果 建立的检测Hp 16S rRNA基因及cagA基因的多重PCR方法特异性强,灵敏性较高,最低检测线为103 copies· μL-1;重组质粒pGMT-16s和pGMT-cagA,可作为鉴定Hp的标准阳性对照品;检测Hp感染的消化道疾病患者的唾液标本,口腔携带Hp 16S rRNA基因的阳性率为87.2%,cagA基因阳性率为23.1%。结论 Hp感染的消化道疾病患者口腔唾液标本中存在Hp,口腔中存在Hp可能是诱发消化道Hp感染及治疗后复发的一个重要原因。     

成都地区幽门螺杆菌感染现状及相关影响因素分析

目的 了解成都地区人群幽门螺杆菌 （Helicobacler pylori, Hp）感染现状及相关影响因素,为制定本地区Hp防治方案提供依据。方法 以在四川大学华西医院健康体检中心行常规体检的成都籍常住居民为研究对象,通过¹⁴C尿素呼气试验 （¹⁴C-urea breath test,¹⁴C-UBT）检测Hp感染状况;随机抽取部分个体进行问卷调查,了解Hp感染的相关影响因素。结果 共纳入体检者8 365例,500份问卷中共收集合格问卷497份。受检人群的Hp总感染率为53.1%,男性高于女性〔54.1% （2 673/4 941）vs. 51.7%（1 771/3 424）, P<0.05〕;30岁及30岁以上各年龄段的Hp感染率均达到或超过50%。藏族人群的Hp感染率高于汉族〔74.2% (23/31) vs. 48.6%(216/444),P<0.05〕;生吃大蒜者Hp感染率低于不食用者〔52.6% (231/439) vs. 67.9%(38/56),P<0.05〕;有呕吐症状者的Hp感染率高于无症状者〔63.4%(59/93) vs. 52.2%(211/404), P<0.05〕。男性〔标准偏回归系数(β)=0.155 9〕、藏族(β=0.148 9)、有呕吐症状(β=0.146 9)是Hp感染的危险因素,生吃大蒜(β=-0.149 0)是防止Hp感染的保护因素。结论 成都地区人群具有较高的Hp感染率。男性、藏族、有呕吐症状是Hp感染的独立危险因素;而经常生吃大蒜则对Hp感染有一定的保护作用。     

PCR检测实验恒河猴和食蟹猴群体中幽门螺杆菌和“猕猴螺杆菌”的感染

目的调查国内实验恒河猴和食蟹猴中幽门螺杆菌和"猕猴螺杆菌"的感染情况。方法参考文献中的螺杆菌属16S rRNA和幽门螺杆菌16S rRNA的引物序列,和新设计的"猕猴螺杆菌"16S rRNA特异性引物,在人工养殖的45只成年恒河猴和90只成年食蟹猴粪便样本中,通过q PCR或常规PCR检测来初步调查这两种猕猴中两种螺杆菌的感染情况。结果在恒河猴中幽门螺杆菌和"猕猴螺杆菌"的感染率均为100%,在食蟹猴中幽门螺杆菌和"猕猴螺杆菌"的感染率分别为100%和97.8%。结论证实我国人工繁育饲养的恒河猴和食蟹猴普遍存在"猕猴螺杆菌"感染。幽门螺杆菌和"猕猴螺杆菌"几乎同时存在于所有人工繁育的实验猴个体中,可能会对这两种猕猴的健康以及相关动物实验结果的准确性存在不利影响。     

巢氏PCR—RFLP和多重PCR检测HBV基因型、基因亚型方法的比较

目的:建立HBV基因型和亚型的分型方法,并分析相关的两种方法特异性和敏感性。方法:采用型特异性引物的巢氏PCR-RFLP和六种主要的HBV型特异性引物和亚型特异性引物的多重PCR方法,分别检测了100例患者标本。结果:两法不一致率为50%(27/54)。型特异性引物巢氏PCR-RFLP法检测出B基因型41例(41%),C基因型25例(25%),B C基因型34例(34%),B j亚型3例(7.3%),Ba亚型为38例(92.7%),Cs亚型为21例(84%),Ce亚型为3例(12%),1例C型未分出亚型(4%)。多重PCR法检出B型18例(33.3%),C型7例(13%),B C混和型5例(9.3%),B2亚型2例(11%),C1亚型2例(28.5%)。巢氏PCR-RFLP法型检出率100%亚型检出率98.5%,多重PCR法型检出率55.6%,亚型检出率仅为16%,前者高于后者(P<0.05)。结论:巢氏PCR-RFLP鉴定HBV基因型、基因亚型较多重PCR敏感性高,重复性好,但耗时长,费用高。     

幽门螺杆菌多表位重组原核表达工程菌的构建及表达特性研究

目的 构建含有幽门螺杆菌尿素酶（UreI、UreB）及粘附素（HpaA）的多表位原核表达质粒pET28a(+)/ureI-ureB-hpaA〔pET28a(+)/IBA〕及相应的原核表达工程菌,研究其表达特性。 方法 通过生物信息学方法从ureI 、ureB和 hpaA基因中筛选T细胞和B细胞优势表位基因序列,人工合成并构建原核重组表达质粒pET28a(+)/IBA。经限制性内切酶（Nde Ⅰ,Xho Ⅰ）酶切鉴定及DNA测序鉴定后导入大肠杆菌BL21 (DE3) 。该工程菌经IPTG诱导后,用SDS-PAGE检测重组蛋白（rIBA）的表达情况,以抗幽门螺杆菌悉尼株（SS1株）特异卵黄抗体采用Western blot检测rIBA的抗原性。 结果 构建的多表位原核表达质粒pET28a(+)/IBA双酶切和测序鉴定与设计序列100%一致。工程菌经 IPTG 诱导后SDS-PAGE电泳显示在相对分子质量40×10 ³左右有一条明显蛋白条带,Western blot显示有相应位置特异反应条带。 结论 成功构建幽门螺杆菌多表位重组原核表达质粒pET28a(+)/IBA及相应原核表达工程菌,该工程菌表达的rIBA具有抗原性,表明该重组蛋白与幽门螺杆菌有高度相关性。