幽门螺杆菌对胃粘膜损伤机制的实验研究

实验采用ＨＰ 活菌悬液,制成大鼠ＨＰ 损伤性胃炎模型,以便观察ＨＰ 对胃粘膜的损伤机制。结果表明：实验组与对照组比较,胃粘膜损伤指数增高（Ｐ＜ ０．０５） ,胃壁结合粘液量明显降低（Ｐ＜ ０．０１） ,胃粘膜ＰＧＥ２ 和ＳＳ 的含量降低（Ｐ＜ ０．０１） 。说明幽门螺杆菌对胃粘膜防御系统有明显的损伤作用。     

动物胃内螺旋菌的分类与鉴定

本文对猪、狗和猫胃内的螺旋样细菌进行了调查,用常规病理学技术发现这些动物胃内主要有三种类型的是螺旋菌：幽门螺杆菌样、人胃螺旋菌样和弯曲菌样微生物,在三只猫胃培养出ＨＰ样细菌,用螺杆菌属细菌特异探针杂交发现ＧＨＬＯｓ帮ＨＰＬＯｓ属于螺杆菌属细菌,而用ＨＰＴ特异物ＰＣＲ扩增发现狸和猫胃内存在ＨＰＤＮＡ,猫胃内ＨＰ样培养菌也扩增阳性,从而提出人胃内ＨＰ和ＧＨ感染可能来自动物传播论断。     

幽门螺杆菌分离培养的研究

采用细菌培养法及快速尿素酶法分别检测了１６９例消化道疾病患者幽门螺杆菌（Ｈｅｌｉ－ｃｏｂａｃｔｅｒｐｙｌｏｒｉ,ＨＰ）感染情况。标本经２０％葡萄糖运送培养基运送后,分别涂布于选择性培养基和本室改良的选择性培养基,３７℃微氧环境（５％Ｏ２,１０％ＣＯ２,８５％Ｎ２）培养８天。标本同时采用快速尿毒酶法进行检测。结果表明,细菌培养法与尿素酶法检测阳性率接近,分别为４６％和５５％;细菌培养第６天与第８天其阳性检出率相同;选择性培养基与本室改良选择性培养基对幽门螺杆菌的检出率差别明显,分别为３４％（１７／４９）和５１％（６１／１２０）,同时其杂菌生长率分别为５４％（２９／４９）和２５％（３０／１２０）。     

丹参撮物F对幽门螺杆菌致敏小鼠的免疫调理作用研究

研究丹参提取物Ｆ（Ｄａｎ Ｓｈｅｎ ｅｘｔｒａｃｔ Ｆ,ＤＳＥ－Ｆ）对幽门螺杆菌（Ｈｅｌｉｃｏｂａｃｔｅｒ ｐｙｌｏｒｉ,ＨＰ）致敏胃粘膜固有层淋巴细胞有无免疫调理作用。经口给予小鼠ＨＰ全菌破碎抗原与ＤＳＥ－Ｆ２周后,提取脾淋巴细胞和胃粘膜固有层Ｔ淋巴细胞（ＬＰＬ）,检测对肿瘤细胞的细胞毒活性和ＩＬ－２诱生能力的改变,结果显示ＤＳＥ－Ｆ与ＨＰ抗原协同能增强脾淋巴细胞和胃ＬＰＬ细胞的抗细胞的细胞毒性     

幽门螺杆菌的分子指纹法研究进展

分子指纹法包括：细菌全细胞蛋白ＳＤＳ－ＰＡＧＥ图谱分析法,染色体ＤＮＡ限制酶酶切图谱分析法,ｒＲＮＡ基因限制酶酶切图谱分析法。分子指纹法能敏感表达幽门螺杆菌（ＨＰ）基因变异,从菌株水平准确鉴定ＨＰ,并应用于ＨＰ感染复发,耐药性,致病机理和分子流行病学等重要问题的研究中。     

球形幽门螺杆菌分子生物学研究

为研究幽门螺杆菌（ＨＰ）球形变异本质,作者通过延期培养和采用亚抑菌浓度抗生素,使３株ＨＰ发生球形变异,对弯曲形和球形ＨＰ作了ＳＤＳ－ＰＡＧＥ、免疫印迹及４个毒力基因片段ＰＣＲ和ＰＣＲ－ＳＳＣＰ分析。ＳＤＳ－ＰＡＧＥ图谱显示球形ＨＰ分子量在７４×１０４以上的蛋白含量减少,免疫印迹显示球形ＨＰ１２５×１０４蛋白条带反应减弱,而抗生素诱变的球形ＨＰ分子量为１１×１０４和６３×１０４的蛋白条带反应增强。ＰＣＲ及ＰＣＲ－ＳＳＣＰ结果表明球形ＨＰ的ｈｐａＡ,ＶａｃＡ,ＣａｇＡ和ＵｒｅＡ４个毒力基因片段未发生缺失,但在ｈｐａＡ或ＶａｃＡ基因中存在点突变     

幽门螺杆菌的基因分型方法及其应用

近几年,有关幽门螺杆菌（ＨＰ）基因分型方法及其应用的研究取得了很大进展。基因分型方法包括：质粒分型、限制性内切酶分型（ＲＥＡ）、核糖分型、染色体ＤＮＡ脉冲场凝胶电泳（ＰＦＧＥ）分型、多聚酶链反应限制性内切酶消化（ＰＣＲ－ＲＦＬＰ）分型、任意引物ＰＣＲ（ＡＰ－ＰＣＲ）分型、ＰＣＲ单链构型多态性（ＰＣＲ－ＳＳＣＰ）分型和核苷酸序列分析等。基因分型方法广泛用于ＨＰ的研究,如基因图的构建、感染复发、耐药机     

氧氟沙星抗生素对幽门螺杆菌的敏感性试验

为了测定氧氟沙星等抗生素对幽门螺杆菌的敏感性,采用纸片扩散法和测定最低抑菌浓度（ｍｉｎｉｍａｌｉｎｈｉｂｉｔｏｒｙｃｏｎｃｅｎｔｒａｔｉｏｎ,ＭＩＣ）相结合对临床分离幽门螺杆菌（ＨＰ）及标准菌株进行了测验。结果氧氟沙星对ＨＰ的敏感性最高,是治疗Ｈｐ的有效药物。     

幽门螺杆菌感染的诊断和治疗

本文阐述幽门螺杆菌（ＨＰ）在消化性溃疡病中的作用以及ＨＰ感染的诊断和治疗,着重介绍清除ＨＰ的一些药物及治疗方案。     

幽门螺杆菌疫苗的研究现状

幽门螺杆菌（ＨＨ）是慢性胃炎和消化性溃疡的主要病因,并与胃癌的发生密切相关,其相关致病因子主要包括尿素酶、细胞粘附素、过氧化氢酶、脂酶、蛋白酶、细菌毒素和能导致炎症反应的物质。ＨＰ的致病机理与ＨＰ的致病性和宿主免疫应答有关,尤以细菌的毒性占主导地位。近年来国内外均关注ＨＰ的免疫预防和治疗。由于ＨＰ减毒活疫苗的研究条件尚不成熟,目前正重点进行全菌体死疫苗、组分疫苗及基因工程疫苗的研究,ＨＰ动物模型、疫苗的免疫途径、免疫佐剂的研究已取得了令人满意的进展,ＨＰ疫苗的治疗作用更引起了人们的关注。本文对ＨＰ的致病机理、疫苗的研究进展等做一综述。     

Immunological aspects of Helicobacter pylori infection.

Host defence against Helicobacter pylori infection is a complex system of both specific and non-specific reactions. Among the non-specific defense mechanisms acting on bacteria before they reach the mucus layer in the stomach are digestive enzymes, lyzozyme, lactoferrin and other components with antimicrobal activity. The mucus layer is the final non-specific barrier against the bacteria reaching the gastric mucosa cells. On reaching the gastric mucosa Helicobacter pylori adheres to epithelial cells and bacterial antigens, chemotaxins and other components are liberated. Helicobacter pylori antigens are presented to immunate B lymphocytes, which interact with T-helper lymphocytes to become mature IgA-, IgD-, IgE-, IgG and Ig-M producing plasma cells. IgA dimers of secretory IgA are secreted through the gastric epithelium. IgE antibodies bind to basophils, which mature to histamine-producing mast cells. Histamine activates the acid production in the stomach and contributes to the chronic inflammation and tissue destruction. In addition, T lymphocytes are possible activated by Helicobacter pylori and contribute to the chronic inflammation.     

Demonstration of a pH gradient in the gastric gland of the acid-secreting guinea pig mucosa

The gastric mucosa is covered by a continuous layer of mucus. Although important for understanding the mechanism of this protective function, only scarce information exists about the pH inside the gastric gland and its outlet. pH in the lumen of the gastric glands, in the outlet of gastric crypts, and in the adjacent cells was measured in the isolated acid-secreting mucosa of the guinea pig. Ultrafine double-barreled pH microelectrodes were advanced at high acceleration rates through the gastric mucus and the tissue to ensure precise intracellular and gland lumen pH measurements. A pH gradient was found to exist along the gastric gland, where the pH is 3.0 at parietal cells, i.e., in the deepest regions, and increases to 4.6 at the crypt outlet. Intracellular pH (pH(i)) of epithelial cells bordering a crypt outlet, and of neck cells bordering a gland, was acidic, averaging 6.0 and 6.5, respectively. pH(i) of deep cells bordering a gland was nearly neutral, averaging 7.1, and the secreting parietal cells were characterized by a slightly alkaline pH(i) of 7.5. This gland pH gradient is in general agreement with a model that we recently proposed for proton transport in the gastric mucus, in which protons secreted by the parietal cells are buffered to and transported with the simultaneously secreted mucus toward the gastric lumen, where they are liberated from the degraded mucus.     

The lipoprotein HP1454 of Helicobacter pylori regulates T‐cell response by shaping T‐cell receptor signalling

Helicobacter pylori (HP) is a Gram‐negative bacterium that chronically infects the stomach of more than 50% of human population and represents a major cause of gastric cancer, gastric lymphoma, gastric autoimmunity, and peptic ulcer. It still remains to be elucidated, which HP virulence factors are important in the development of gastric disorders. Here, we analysed the role of the HP protein HP1454 in the host–pathogen interaction. We found that a significant proportion of T cells isolated from HP patients with chronic gastritis and gastric adenocarcinoma proliferated in response to HP1454. Moreover, we demonstrated in vivo that HP1454 protein drives Th1/Th17 inflammatory responses. We further analysed the in vitro response of human T cells exposed either to an HP wild‐type strain or to a strain with a deletion of the hp1454 gene, and we revealed that HP1454 triggers the T‐cell antigen receptor‐dependent signalling and lymphocyte proliferation, as well as the CXCL12‐dependent cell adhesion and migration. Our study findings prove that HP1454 is a crucial bacterial factor that exerts its proinflammatory activity by directly modulating the T‐cell response. The relevance of these results can be appreciated by considering that compelling evidence suggest that chronic gastric inflammation, a condition that paves the way to HP‐associated diseases, is dependent on T cells.     

cagA+ Helicobacter pylori induces greater levels of prostaglandin E2 than cagA- strains

cagA+ Helicobacter pylori (HP) infection is associated with an increased risk of distal gastric cancer. Previous studies investigating the effect of HP infection on prostaglandin E2 (PGE2) levels have not differentiated between cagA+ and cagA- strains and consequently have produced contradictory results. The aim was to investigate the effect of cagA+ strains on PGE2 and enhance the understanding of the mechanisms leading to gastric diseases. Hundred patients without peptic ulcers and not on medication were recruited (one later excluded) from endoscopy clinics: six biopsies were obtained from each patient. PGE2, colonization density and histology were determined. In addition, HP status was assessed by histology, CLOtest and culture with cagA+ being determined by PCR. Sixty-nine patients were HP- and 30 HP+ (10 cagA+, 18 cagA-, 2 undetermined). In age and sex-matched patients, PGE2 was significantly greater (P = 0.04) in HP+ (37.2 +/- 1.2 pg/mg per 20 min) than in HP- (22.6 +/- 1.2). In patients without atrophy, those infected with cagA+ had significantly higher (P = 0.03) PGE2 levels (53 +/- 1.1) than HP- patients (22.6 +/- 1.1) and greater levels (P = 0.29) than cagA- patients (35 +/- 1.3). In conclusion, the increased levels of PGE2 in the presence of cagA+ infection could be an important factor by which cagA+ strains enhance the gastric mucus layer protective functions leading to established colonization, gastritis and increased risk of gastric cancer. However, further evaluation with a large-scale multi-centre study is required to substantiate this hypothesis.     

The gastric mucus layers: constituents and regulation of accumulation

The mucus layer continuously covering the gastric mucosa consists of a loosely adherent layer that can be easily removed by suction, leaving a firmly adherent mucus layer attached to the epithelium. These two layers exhibit different gastroprotective roles; therefore, individual regulation of thickness and mucin composition were studied. Mucus thickness was measured in vivo with micropipettes in anesthetized mice [isoflurane; C57BL/6, Muc1-/-, inducible nitric oxide synthase (iNOS)-/-, and neuronal NOS (nNOS)-/-] and rats (inactin) after surgical exposure of the gastric mucosa. The two mucus layers covering the gastric mucosa were differently regulated. Luminal administration of PGE(2) increased the thickness of both layers, whereas luminal NO stimulated only firmly adherent mucus accumulation. A new gastroprotective role for iNOS was indicated since iNOS-deficient mice had thinner firmly adherent mucus layers and a lower mucus accumulation rate, whereas nNOS did not appear to be involved in mucus secretion. Downregulation of gastric mucus accumulation was observed in Muc1-/- mice. Both the firmly and loosely adherent mucus layers consisted of Muc5ac mucins. In conclusion, this study showed that, even though both the two mucus layers covering the gastric mucosa consist of Muc5ac, they are differently regulated by luminal PGE(2) and NO. A new gastroprotective role for iNOS was indicated since iNOS-/- mice had a thinner firmly adherent mucus layer. In addition, a regulatory role of Muc1 was demonstrated since downregulation of gastric mucus accumulation was observed in Muc1-/- mice.     

慢性胃病患者胃蛋白酶原I、II水平与幽门螺旋杆菌感染的关系研究

目的:探讨慢性胃病患者胃蛋白酶原(PG)Ⅰ、PG Ⅱ水平与幽门螺旋杆菌(HP)感染的关系。方法:选取2012年12月-2016年12月期间我院收治的慢性胃病患者64例作为研究对象,根据疾病类型分为慢性胃炎组23例、胃溃疡组22例以及胃癌组19例。另取同期于我院接受体检的健康志愿者30例作为对照组,应用免疫比浊法测定各组血清PG Ⅰ与PG Ⅱ水平,采用快速尿激酶法测定各组HP感染情况,分别对比各组研究对象HP感染发生情况,血清PG Ⅰ、PG Ⅱ、PG Ⅰ/PG Ⅱ水平,HP感染情况与血清PG Ⅰ、PG Ⅱ、PG Ⅰ/PG Ⅱ水平关系。结果:慢性胃炎组、胃溃疡组以及胃癌组患者HP阳性率分别为60.87%、63.64%、78.95%,均明显高于对照组的13.33%(P0.05)。慢性胃炎组、胃溃疡组以及胃癌组患者血清PG Ⅰ、PG Ⅰ/PG Ⅱ水平均低于对照组,且胃癌组低于慢性胃炎组与胃溃疡组(P0.05),慢性胃炎组和胃溃疡组血清PG Ⅰ、PG Ⅰ/PG Ⅱ水平比较差异无统计学意义(P0.05),各组血清PG Ⅱ比较无统计学差异(P0.05)。各组研究对象HP阳性血清PG Ⅰ、PG Ⅰ/PG Ⅱ水平均低于HP阴性(P0.05),而PG Ⅱ水平比较无统计学差异(P0.05),慢性胃炎组、胃溃疡组、胃癌组HP阳性血清PG Ⅰ水平低于对照组,且胃癌组低于慢性胃炎组、胃溃疡组(P0.05),胃溃疡组、胃癌组HP阳性血清PG Ⅰ/PG Ⅱ水平低于对照组,且胃癌组低于慢性胃炎组(P0.05)。结论:慢性胃病患者PG Ⅰ、PG Ⅱ水平异常降低,HP阳性患者PG Ⅰ、PG Ⅱ水平降低更为明显,随病变的程度增加,血清PG Ⅰ、PG Ⅰ/PG Ⅱ水平也呈现出下降的趋势。     

胃癌患者胃粘膜微生物群改变的初步研究

对１０２例具有消化不良症状的患者做胃镜检查,并取胃粘膜组织进行细菌的分离培养。结果表明,不同的消化道疾病,胃粘膜微生物群均发生不同的改变。其中胃癌患者改变最明显,胃内微生物检出率最高,幽门螺杆菌检出率为５２９４％（１８／３４）,无芽胞厌氧菌检出率为８８２４％（３０／３４）,其中产亚硝酸优杆菌检出率为５５８８％（１９／３４）,硝酸盐还原试验阳性菌株占７０５９％（２４／３４）。     

Interactions of EGF and ornithine decarboxylase activity in the regulation of gastric mucus synthesis in cigarette smoke exposed rats

Cigarette smoking has been shown to aggravate ulceration and delay ulcer healing. Smokers had a lower level of mucus in their stomachs. In the present study, we examined whether cigarette smoke or its extract reduced mucus production through the suppression of epidermal growth factor (EGF) associated with the reduction of polyamine biosynthesis both in vivo and in vitro. Ornithine decarboxylase (ODC) activities and mucus synthesis were determined in rat gastric mucosa and in human MKN-28 cells. Incubation of MKN-28 cells with EGF (0.01-1.00 ng/mL) significantly increased mucus synthesis in vitro, which was accompanied by an increase of ODC activity. Removal of salivary glands decreased the circulated EGF level and induced a significant reduction of mucus-secreting layer thickness in the gastric mucosa. Cigarette smoke or its extract markedly decreased mucus synthesis in vivo and in vitro, both of which could be completely reversed by intravenous administration of EGF (20 microg/kg) in rats or co-incubation with EGF (1 and 2 ng/mL) in MKN-28 cells. However, ODC activities, which were suppressed by cigarette smoke or its extract, were unaffected by intravenous administration of EGF in rats, or only partially reversed by co-incubation with EGF in MKN-28 cells. These findings indicate that both EGF and ODC activity represent two different entities in the modulation of cigarette smoking on gastric mucus synthesis. The action of EGF on mucus synthesis may only be partially if not dependent on ODC activity in the stomach.     

Peptic erosion of gastric mucus in the rat

1. The effect of pepsin on the loss of mucus glycoprotein from the gastric epithelial mucus layer was studied in the rat. 2. Pepsin was instilled into the gastric lumen, and luminal contents were subsequently assayed. 3. Glycoprotein loss increased with luminal pepsin, up to a concentration of 1 mg pepsin/ml. 4. Luminal glycoprotein had a molecular size distribution intermediate between subunit, and native mucus glycoprotein of the epithelial mucus layer. 5. Incubation of gastric epithelial scrapings with pepsin demonstrated that insoluble, native mucus glycoprotein was rapidly degraded to soluble glycoprotein of similar molecular size distribution to that found in vivo in the lumen.