幽门螺杆菌相关受体的研究进展

幽门螺杆菌(Hp)不仅可以引起胃炎和消化性溃疡，而且是胃癌的危险因素。但Hp如何致病尚未阐明，因此Hp与宿主之间如何相互作用是目前研究的热点之一，已受到人们的广泛重视。     

幽门螺杆菌致病因子研究进展

本文从粘附、定植、毒力等三个方面简述了幽门螺杆菌的致病因子,对于理解幽门螺杆菌的致病性和致病机理具有重要意义。     

头花蓼对幽门螺杆菌粘附定植的影响

目的观察头花蓼水提物对幽门螺杆菌(Helicobacter pylori,H. pylori)粘附定植的影响。方法采用尿素酶活性比色法定量检测头花蓼水提物作用前后幽门螺杆菌尿素酶活性的影响;运用半固体布氏琼脂平板法检测不同浓度头花蓼对幽门螺杆菌鞭毛运动的影响;利用细胞爬片革兰染色观察不同浓度头花蓼作用后幽门螺杆菌在GES-1细胞表面粘附的变化并计算各组抑制率;采用Real-time PCR 技术检测头花蓼作用前后相关基因ureB、ureE、ureF、flaA、flaB、babA、alpA、alpB的mRNA转录水平。结果头花蓼水提物对幽门螺杆菌尿素酶活性具有抑制作用,抑制率为44.90±0.289。头花蓼浓度为1/2MIC、1/4MIC、1/8MIC分别作用后幽门螺杆菌菌膜晕圈直径显著小于对照组, 分别为(5.67±0.55)mm ,(8.5±0.50)mm ,(11.67±1.53)mm,差异有统计学意义(P<0.05);不同浓度头花蓼水提物均能抑制细菌粘附胃上皮细胞,各浓度组与对照组比较,差异有统计学意义(P<0.05)。头花蓼作用后,与对照组比较,下调了尿素酶结构基因ureB,尿素酶活性基因ureE、ureF、鞭毛相关基因flaB、flaA以及粘附素基因babA、alpA、alpB mRNA的转录水平,差异均具有统计学意义(P<0.05)。结论头花蓼对幽门螺杆菌具有明显的抑制作用,是通过抑制幽门螺杆菌尿素酶活性,减缓幽门螺杆菌的鞭毛动力,影响幽门螺杆菌对胃粘膜上皮细胞的粘附等方面发挥其抑菌作用。     

幽门螺杆菌致病机制的研究进展

幽门螺杆菌(Hp)在我国的感染率较高,是引起胃肠疾病的重要因素[1],除了会引发宿主一系列的胃肠道症状和组织损伤以外,还会致使肿瘤细胞生长,是一种不可小觑的致癌因素。为此,我们有必要明确Hp的致病机制,为预防和治疗Hp感染提供理论依据和更为广泛的治疗思路。Hp致病机制大致可以分为黏附机制、引起症状和胃黏膜损伤的机制、免疫机制和致癌机制几大类,现分别进行综述。1 黏附、定植机制鞭毛是Hp的重要结构,分为鞭毛细丝和钩子.     

幽门螺杆菌研究进展

自1982 年澳大利亚学者Warren 和Marshall 首先从人胃黏膜中培养出幽门螺杆菌(Helicobacter pylori,H.p) 以来的20余年,随着对H.p的不断深入研究,已将其确定为慢性活动性胃炎和消化性溃疡的重要致病菌,并与胃腺癌和胃粘膜相关性淋巴组织(MALT)淋巴瘤关系密切.世界卫生组织癌症研究委员会早在1994 年就将H.p列为Ⅰ类致癌原,两位发现者则于2005 年荣获了诺贝尔医学奖.本文谨对其最新研究进展综述如下.     

幽门螺杆菌的致病机制

幽门螺杆菌(Hp)已发现15年，经研究Hp感染与人B型胃炎和消化性溃疡密切相关，如不治疗，感染可持续多年，而且对胃癌的发生是个重要的危险因素，造成这种反应的差异有细菌毒力和宿主免疫应答两方面的原因。Hp的致病机制有赖于毒力(定居)因素和致病因素，Hp具有适应性酶和蛋白以及牯附于细胞的能力，使其在胃腔不利的环境中得以生存；其分泌的毒素和诱导的炎性介质，直接破坏胃粘膜屏障或引起胃酸和消化活性的改变而导致胃牯膜损伤，本文将重点讨论几个与Hp致病机制有关的因素。     

cag致病岛与幽门螺杆菌致病作用的关系

幽门螺杆菌（Ｈ．Ｐｙｌｏｒｉ）诱导疾病发生的分子机制目前尚不清楚,针对Ｈ． ｐｙｌｏｒｉ致病相关因素的研究仍在继续深人。１９９６年Ｃｅｎｓｉｎｉ等［１］在ｃａｇＡ阳性Ｈ ｐｙｌｏｒｉ菌株中发现的新的ＤＮＡ片段──ｃａａ致病岛,被认为是Ｈ． ｐｙｌｏｒｉ中的又一致病相关因素。本文就ｃａｇ致病岛与Ｈ．ｐｙｌｏｒｉ相关致病因子的关系作一简要综述。 一、致病岛的概念 致病菌中编码毒素、粘附因子、侵袭因子或其他毒力因子的致病基因存在于细菌染色体特定区域中,并出现于诸如转座子、质粒、噬菌体等可转染的遗传学元件中…     

幽门螺杆菌尿素酶试剂的比较

幽门螺杆菌尿素酶试剂的比较肖清水自从１９８３年澳大利亚学者Ｍａｒｓｈａｌ和Ｗａｒｒｅｎ首先报道从人胃粘膜活体标本中成功地分离出幽门螺杆菌（ｈｅｌｉｃｏｂａｃｔｅｒｐｙｌｏｒｉ，Ｈｐ）以来，国内外学者对此进行了广泛深入地研究。在临床上对患者进行胃镜检查...     

阿司匹林对幽门螺杆菌定植的影响

目的:探讨阿司匹林体外培养条件下对H pylori定植相关因子的影响及其机制.方法:阿司匹林与H pylori共同培养,电镜观察其形态结构,3 g/L的琼脂穿刺培养观察细菌动力,酶联免疫吸附试验(ELISA)检测不同浓度阿司匹林对H pylori黏附性的影响.SYBRgreen Ⅰ实时定量PCR测定编码H pylori鞭毛蛋白基因(flaA、flaB)、尿素酶基因(ureA、ureB)以及黏附素基因(babA、sabA、alpA、alpB、hpaA、hopZ)的表达.结果:体外培养条件下,阿司匹林导致H pylori形态发生改变,细菌胞壁不完整,且发生不同程度的凹陷变形,细菌细胞壁和细胞膜间出现空隙,胞质分布不均匀,出现高电子密度颗粒,并有溶菌样改变.阿司匹林显著降低H pylori的鞭毛动力,并剂量依赖性的抑制Hpylori对AGS细胞的黏附.阿司匹林降低H pylori鞭毛蛋白基因(flaA、flaB)mRNA水平的表达,增加尿素酶基因(ureA、ureB)及黏附素基因(babA,sabA、alpA,alpa,hpaA,hopZ)mRNA水平的表达(均P<0.05).结论:阿司匹林通过破坏H Pylori的正常结构,降低细茵的动力及黏附性,从而降低细菌的定植能力.     

幽门螺杆菌毒力致病因子研究进展

幽门螺杆菌( Helicobacter pylori, H pylori)感染是一种世界范围内常见的慢性感染, 可致多种疾病, 如: 慢性胃炎, 十二指肠溃疡, 胃黏膜相关的淋巴样组织淋巴瘤及胃腺癌. 不同疾病是由H pylori和宿主之间复杂的致病机制导致. 近年来, 学者们对H pylori毒力致病因子的研究取得了长足进展, 为揭开H pylori感染的致病机制奠定了基础. 本文就H pylori毒力致病因子CagA、VacA、BabA、SabA、OipA、DupA等的最新研究进展进行了综述.     

Helicobacter pylori colonization of the human gastric epithelium: A bug's first step is a novel target for us

After Helicobacter pylori enters the stomach, three steps are vital for infection: (i) establishing colonization; (ii) evading host immunity; and (iii) invading gastric mucosa; the last step is what is associated with diverse outcomes. Urease activity and motility mediated by the flagella of H. pylori are important in harboring colonies beneath the gastric mucus in niches adjacent to the epithelium. Several putative adhesins attach the organism to the gastric epithelium and prompt the succeeding processes for evading host immunity and invading the mucosa. Successful colonization is thus the leading and critical step. From another point of view, this can be a novel target to control this common and important infection. This review summarizes the putative adhesins that influence the evasion of host immunity, and how these could determine different clinico‐pathologic outcomes. The putative adhesins include the interplay between bacterial and host Lewis antigens (type I: Le^a and Le^b; type II: Le^x and Le^y), the dominant pathway between BabA and Le^b, the SabA adhesin binding to sialylated Le^x that is upregulated in inflamed gastric tissue or those with weak‐Le^b, the CagL apparatus to adapt with the α5β1 integrin to mediate a type IV secretory system for CagA translocation into the epithelium; and other outer membrane proteins as HopZ, AlpA/AlpB, or OipA, without known corresponding receptors. This review implicates the adhesins vital for bugs that could be alternatively provided as novel targets for us to overcome the colonization.     

Immunological rapid urease test using monoclonal antibody for Helicobacter pylori

BACKGROUND AND AIM: The current diagnostic methods for detecting Helicobacter pylori infection include rapid urease test (RUT), urea breath test (UBT), histology, culture, and serum antibody detection. The present study evaluated the efficacy of a novel highly specific test, an immunological RUT (IRUT), that uses a monoclonal antibody against H. pylori urease. METHODS: The clinical evaluation of the IRUT was performed in 100 subjects. Each gastric mucus sample obtained during endoscopic examination was incubated for 15 min with a solid tip coated with monoclonal antibody for H. pylori urease, and then the tip was introduced into a pH-monitoring cell containing urea solution. The change in pH of the solution after the enzymatic reaction (delta pH) was measured. The performance of the IRUT was compared with culture, histology, RUT, and UBT. RESULTS: Of the 47 H. pylori-positive subjects, 43 were IRUT positive (sensitivity, 91.5%), and of the 53 H. pylori-negative subjects, 52 were negative (specificity, 98.1%). Compared with the usual diagnostic methods, IRUT had high sensitivity and specificity for the detection of H. pylori and was no less efficient. CONCLUSIONS: IRUT is a sensitive, specific and very rapid (within 20 min) method of detecting H. pylori infection.     

Modified rapid urease test for Helicobacter pylori detection in relation to an immunohistochemical stain

BACKGROUND: The rapid urease test and touch cytology have been used for the rapid detection of Helicobacter pylori infection. Recently, a modified rapid urease (MRU) test, which provides results in 20 min has been available on a commercial basis. To date, few reports have evaluated the accuracy of this test. This study evaluated the sensitivity, specificity, and accuracy of the MRU test and touch cytology to detect H. pylori in relation to the density of H. pylori infection determined semi-quantitatively by using immunohistochemical stains. METHODS: Biopsy specimens obtained from a total of 60 patients who underwent endoscopy for evaluation of gastroduodenal diseases were studied by using the MRU test, Giemsa stain for touch smear tissue and histological methods. An immunohistochemical stain was used as a standard, and the density of H. pylori infection was graded according to the number of individual bacteria seen as follows: grade 0 = 0; grade 1+ = 1-9; grade 2+ = 10-29; grade 3+ = 30-99; grade 4+ > or = 100. The severity of gastritis was evaluated histologically in each specimen and compared with the density of H. pylori infection. RESULTS: The MRU test had an overall sensitivity of 73%, specificity of 100% and accuracy of 85%. The Giemsa stain had a sensitivity of 91%, specificity of 100% and accuracy of 95%.The sensitivities of the MRU test and Giemsa stain decreased in mild H. pylori infection. In the MRU test, the sensitivity was 47% when the density of H. pylori infection was 1+, while 80-100% sensitivities were obtained when the densities of infection were > or = 2+. With the Giemsa stain, the sensitivity was 80% when the density was 1+, while the sensitivity increased to 100% when the densities were > or = 2+. The severity of gastritis determined by the Rauws scores showed a positive correlation with the density of H. pylori infection as evaluated by immunohistochemical staining. CONCLUSIONS: The MRU test had high sensitivity and specificity for moderate to severe H. pylori infection, but it may result in false-negative results in tests for mild infection. As the MRU test has the advantages of shorter incubation times and low cost, a combination of the MRU test and the Giemsa stain for touch cytology may be the most time- and cost-efficient tests in a clinical setting for the diagnosis of H. pylori infection.     

幽门螺杆菌根除效果的影响因素分析

幽门螺杆菌(Helicobacter pylori,H.pylori)感染是最常见的细菌感染之一,影响着世界约50%的人口,被世界卫生组织定义为胃癌致病因子。H.pylori根除治疗可以降低消化性溃疡、胃癌等疾病的发病风险。目前H.pylori根除率呈逐渐下降的趋势。加深对其根除率影响因素的了解,可能有助于制定更为有效的根除治疗或预防感染的方案。本文结合国内外相关研究,对影响H.pylori根除率的因素作一概述。     

Celecoxib inhibits Helicobacter pylori colonization-related factors

AIM:To investigate the effect of celecoxib,a selective COX-2 inhibitor,on Helicobacter pylori(H.pylori) colonization-related factors and its mechanism.METHODS:After co-incubation with celecoxib,morphology of H.pylori strain 26695 was observed under a transmission electron microscope.Flagella motility was assessed by stab agar motility test.Adherence of H.pylori to AGS cells was determined by enzyme linked immunosorbent assay.Levels of mRNA expression in flagellar genes(flaA,flaB),urease genes(ureA,ureB)and ...     

幽门螺杆菌检测方法研究新进展

本文就近年来幽门螺杆菌检测方法新进展作一简要的概述,主要从细菌培养、快速尿素酶实验、组织学检查、尿素呼气实验、抗体检测、粪便抗原检测和分子生物学检测等几个方面展开。     

幽门螺杆菌豚鼠模型的构建

目的利用豚鼠构建幽门螺杆菌(Helicobacter pylori,H.pylori)定植模型。方法模型组豚鼠以1×107CFU/只H.pyloriSS1菌株灌胃,隔天1次,共2次。H.pylori攻击前,动物禁食水12 h,灌胃后4 h恢复食水供给。对照组每次灌胃100μl/只布氏培养基,2周后处死动物,取胃组织进行尿素酶活性检查、细菌分离培养、组织学检查。结果模型组动物尿素酶检测及细菌分离培养均呈阳性,组织学检查表明豚鼠胃组织在H.pylori定植2周后可见炎症反应。结论豚鼠对H.pylori敏感可以作为H.pylori定植的模型动物。     

幽门螺杆菌根除治疗前后快速尿素酶试验诊断的准确性

目的 评价快速尿素酶试验(RUT)在根除治疗前后诊断幽门螺杆菌(Hp)感染的准确性。方法 选择250例接受胃镜检查的患者，123例无Hp根除治疗史，127例为Hp根除治疗后复查患者。每例患者取胃窦和胃体活检标本各3块，分别用于RUT、细菌培养和病理组织学检查。以细菌培养及病理组织学检查结果作为“金标准”，即培养和(或)组织学检查结果阳性者为Hp阳性，而培养和组织学检查结果同时阴性者为HP阴性或HP根除。结果 末行Hp根除治疗的患者RUT正确的诊断了86例Hp阳性中的84例和37例Hp阴性中的34例，其敏感性和特异性分别为97．7％和91.9％。根除治疗后RUT敏感性和特异性分别为64.3％和99.0％。然而，根除治疗后6个月以上复查胃镜，RUT敏感性和特异性均达100％。结论 根除治疗前和根除治疗后6个月以上复查，RUT诊断Hp感染准确性高。     

幽门螺杆菌疫苗研究的现状和展望

幽门螺杆菌感染与慢性胃炎、消化性溃疡、胃癌及胃粘膜相关性淋巴瘤有关。疫苗是防治幽门螺杆菌感染切实可行的方法。近年来新的防治和根除幽门螺杆菌感染的疫苗正在开发并取得了很大的进展。本文对新近研制的蛋白组分疫苗、活菌疫苗、DNA疫苗、缓释微球疫苗及表位疫苗等幽门螺杆菌疫苗的进展作一综述。     

喹诺酮类抗生素一线根除幽门螺杆菌研究现状

幽门螺杆菌(Hp)对甲硝唑或克拉霉素耐药率的不断升高是导致根除失败的主要原因。目前喹诺酮类在根除Hp治疗中的作用已受到重视。本文拟就第三代和第四代喹诺酮类药物左氧氟沙星和莫西沙星在一线根除Hp中的作用作一综述。