L’infection par Helicobacter pylori touche environ la moitié de la population mondiale et est responsable de plusieurs pathologies gastrointestinales incluant l’adénocarcinome gastrique. Le développement récent d’un modèle d’étude chez l’animal a permis d’identifier la nature des cellules à l’origine de la transformation cancéreuse en réponse à l’infection chronique par Hélicobacter. Les cellules souches mésenchymateuses de la moelle osseuse (MSC) seraient recrutées au niveau de la muqueuse gastrique afin de reconstituer, par un mécanisme de différenciation épithéliale, les glandes lésées par l’infection. L’adénocarcinome gastrique se développerait à partir des glandes reconstituées par les MSC. Les objectifs de ces travaux ont été d’analyser, in vitro par une approche séquentielle, les différentes étapes responsables de l’initiation tumorale incluant le recrutement des MSC au niveau gastrique, leur différenciation en cellules épithéliales et leur transformation tumorale lors de l’infection par H. pylori. Ces travaux ont tout d’abord démontré que les cellules épithéliales infectées par H. pylori peuvent recruter les MSC après sécrétion de certaines chimiokines. Nous avons ensuite montré que les MSC sont capables de fusionner avec les cellules épithéliales gastriques aboutissant à l’obtention de cellules épithéliales dérivées des MSC. Finalement, les interactions entre H. pylori et les MSC ont été étudiées et ont fourni des premiers éléments de compréhension des mécanismes de l’initiation tumorale. Nos résultats permettent de mieux comprendre le mécanisme physiopathologique de l’adénocarcinome gastrique et seront utiles à la compréhension d’autres cancers dans lesquels le rôle des MSC comme cellules initiatrices de tumeur est suggéré. / Helicobacter pylori infection is found in about half of the world population and can induce several gastrointestinal pathologies including gastric adenocarcinoma. An animal model recently led to the hypothesis of a cellular origin for the cancer initiating cells after Helicobacter infection. Bone marrow-derived mesenchymal stem cells (MSC) are believed to be recruited in the gastric mucosa in order to repair the damages due to infection, by an epithelial differentiation. Gastric carcinoma may rise from MSC reconstituted gastric glands. This study aimed to analyze, by sequential in vitro approaches, the different steps allowing tumor initiation including MSC recruitment by infected epithelial cells, epithelial differentiation of MSC, and cancer marker appearance after H. pylori infection. We first demonstrated that H. pylori infected epithelial cells may recruit MSC by a secretion of cytokines. We then showed that MSC fuse with gastric epithelial cells leading to MSC-derived epithelial cells. Finally, we studied the interaction between H. pylori and epithelial cells providing a preliminary explanation for cancer initiation. Our results allow a better understanding of gastric adenocarcinoma pathophysiology and will be helpful for the understanding of other cancers in which the role of MSC as cancer initiating cells is suspected.

L’infection à Helicobacter pylori est responsable d’une inflammation gastrique chronique qui pourrait contribuer à l’apparition ou l’aggravation de pathologies extradigestives comme la maladie d’Alzheimer (MA). A partir des données de la cohorte PAQUID explorant les facteurs de risque de démence dans une population de patients de plus de 65 ans, nous avons montré que la prévalence de la démence augmentait chez les sujets infectés. Après 20 ans de suivi, l’infection à H. pylori était associée à une augmentation de l’incidence de démence après ajustement aux facteurs de risque connus de MA. Dans une deuxième étude incluant 53 patients atteints de MA, l’infection à H. pylori était associée à des performances cognitives plus sévères et le taux d’homocystéine était positivement corrélé aux lésions cérébrovasculaires et au taux d’anticorps anti-­‐H. pylori. Pour s’affranchir de possibles biais confondant comme le niveau socio-­‐économique, nous avons ensuite évalué l’impact de l’infection à H pylori sur le cerveau de souris sauvages (C57BL/6J) non prédisposées à la MA. Après 18 mois d’infection, alors que l’infection était associée à une inflammation gastrique importante, il n’a pas été retrouvé de plaque amyloïde ou de majoration de la neuroinflammation. Pour aller plus loin, nous avons étudié l’impact de l’infection à H. pylori sur le comportement et les lésions cérébrales de souris transgéniques prédisposées à la MA (APPswe/PS1dE9). Après 6 mois d’infection, les souris transgéniques présentaient plus de plaques amyloïdes sans majoration de la neuroinflammation ni des troubles du comportement.Bien que les études épidémiologiques apportent de nouveaux éléments en faveur d’une association entre la MA et l’infection à H. pylori, les études sur modèle animal ne mettent pas en évidence de majoration des troubles cognitifs ni de la neuroinflammation des souris infectées malgré une majoration du nombre de plaques amyloïdes. D’autres études sont nécessaires pour conclure à une association. / Helicobacter pylori infection seems to play a critical role in extra-­‐gastric diseases including Alzheimer’s dementia (AD). Chronic H. pylori infection could worsen AD lesions via atherosclerosis and inflammation.In a cohort study with 603 non-­‐institutionalized individuals aged 65 and older followed from 1989 to 2008, dementia was more prevalent in the H. pylori-­‐positive group at baseline compared to non-­‐infected group. After 20 years of follow-­‐up, H. pylori infection was determined to be a risk factor for developing dementia after controlling for AD risk factors. In a second study, including 53 AD patients, H. pylori infection was associated with a more pronounced cognitive impairment. Homocysteine levels were positively correlated to cerebrovascular lesions and to H. pylori immunoglobulin levels. To bypass possible confounding biases concerning socio-­‐economic conditions for instance, we evaluated the impact of H. pylori infection on the brain of non-­‐AD predisposed C57BL/6J mice. After an 18-­‐month infection, H. pylori SS1 and H. felis induced a significant gastric inflammation but no brain Aβ deposit was observed in their brain and the infection did not lead to neuroinflammation. To go further, we studied the impact of Helicobacter species infection on cerebral lesions and behaviour of AD transgenic (APPswe/PS1dE9) mice and their wild type littermates. H. pylori infection was associated with an increased number of brain amyloid plaques, but not with an increased neuroinflammation nor a worsening behaviour at 6 and 10 months of age.Although epidemiological studies provided new elements for an association between AD and H. pylori infection, animal model studies did not display a worsening behaviour or an increased neuroinflammation despite an increased number of amyloid plaques. More studies are needed to firmly conclude that there is an association between H. pylori infection and AD.

Reaction of BiPh3 or Bi(OtBu)3 with benzohydroxamic acid (H2-BHA) results in formation of novel mono- and di-anionic hydroxamato complexes; [Bi2(BHA)3]∞1, [Bi(H-BHA)3] 2, [Bi(BHA)(H-BHA)] 3, all of which display nM activity against Helicobacter pylori. Subsequent dissolution of [Bi2(BHA)3]∞ in DMSO/toluene results in hydrolysis to the first structurally authenticated {Bi34} oxido-cluster [Bi34O22(BHA)22(H-BHA)14(DMSO)6] 4. / Dieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Helicobacter pylori ist ein humanpathogenes Bakterium, das den Magen kolonisiert und dadurch eine Immunantwort des Wirts induziert. Statt eine vollständige Eradikation von H. pylori durch die Immunreaktion zu erreichen, kommt es normalerweise zu einer lebenslangen Persistenz des Bakteriums und einer chronischen Infektion. Interessanterweise kommt es infolge einer Infektion zu einer Hochregulation der induzierbaren Stickstoffmonoxid-Synthase (iNOS), aber die zellulären Quellen und zugrundeliegenden Mechanismen von iNOS sind noch nicht vollständig verstanden. Der iNOS-abhängigen Produktion von Stickstoffmonoxid (NO) können sowohl antimikrobielle als auch pathologische Eigenschaften zugeschrieben werden. Daher wurden in der vorliegenden Arbeit iNOS-exprimierende Plasmazellen (PZ) aus der Magenmukosa H. pylori-infizierter Patienten isoliert und phänotypisch, vor allem mittels Durchflusszytometrie und molekularbiologisch hinsichtlich ihres Immunglobulin-Repertoires untersucht. Es wurde erstmals gezeigt, dass mukosale IgA-sezernierende PZ eine der wesentlichen iNOS+ Zelltypen während einer H. pylori-Infektion im Menschen darstellen und zusätzlich wurde ihre intrazelluläre NO-Produktion nachgewiesen. Da iNOS+ PZ in weiteren gastrointestinalen Infektionskrankheiten fehlten, scheint dies kein genereller Phänotyp von PZ der mukosalen Immunabwehr zu sein. Die Analyse der intrazellulären Zytokin-Expression der mukosalen B-Zellpopulationen in H. pylori-Patienten ergab eine Ko-Expression von IFN-γ und TNF-α in iNOS+ memory B-Zellen und eine TNF-α-Expression in iNOS+ PZ, aber nicht in den iNOS− Zellen. Die molekularbiologische Charakterisierung des Immunglobulin-Repertoires von iNOS+ und iNOS− PZ hinsichtlich der VHDJH-Regionen ergab keinen signifikanten Unterschied hinsichtlich der Isotyp-Verteilungen, der Nutzung der VH- und JH-Segmente, CDRH3-Längen sowie somatischen Mutationen und alle Antikörper zeigten typische Charakteristika einer T-zellabhängigen Affinitätsreifung. / Helicobacter pylori is a human-pathogenic bacterium that colonizes the stomach and thereby initiates host immune response. Instead of a complete eradication of H. pylori by the induced immune response, a lifelong bacterial persistence leads to chronic infections. Interestingly, up-regulation of inducible nitric oxide synthase (iNOS) has been observed in gastric mucosal tissue during the course of H. pylori infection in humans, however the cellular sources and underlying mechanisms of iNOS induction are not fully understood. iNOS-dependent production of nitric oxide (NO) is one of the factors commonly linked to both, anti-microbial immunity and pathology. Therefore, in this thesis iNOS-expressing plasma cells (PCs) in the stomach mucosa of H. pylori-infected patients were isolated and phenotypically analyzed by flow cytometry, as well as screened using molecular techniques regarding their immunoglobuline (Ig) repertoires. For the first time, we identified mucosal IgA-producing PCs as a major iNOS+ cell population during H. pylori infection in humans, and additionally confirmed their intracellular nitric oxide production. Since iNOS+ PCs were not detectable in other gastrointestinal infectious diseases, this reaction does not seem to be a general feature of mucosal PCs under conditions of infection. Additionally, intracellular cytokine expression analyses of mucosal B-lineage cells isolated from H. pylori patients revealed a co-expression of IFN-γ and TNF-α in iNOS+ memory B cells and the expression of TNF-α in iNOS+ PCs, but not in iNOS− cells. Molecular analysis of the Ig repertoire of iNOS+ and iNOS− PCs of the VHDJH regions revealed no significant differences regarding the Ig isotype composition, VH and JH gene family usage, CDRH3 length, and frequency of somatic mutations and all antibodies were characterized by typical properties of T cell-dependent affinity maturation.

Bakgrund: Infektion med Helicobacter pylori är vanligt förekommande världen över. Forskning pekar på att låg socioekonomisk status, trångboddhet och dålig hygien tycks gynna smitta med Helicobacter pylori. Helicobacter pylori infekterar magsäckens och/eller tolvfingertarmens slemhinna, vilket kan resultera i magsår och gastrit. Därmed bör behandling sättas in efter påvisad infektion med Helicobacter pylori, för att förebygga risken att magsäckscancer utvecklas. Behandling vid infektion orsakad av Helicobacter pylori innefattar oftast trippelterapibehandling bestående av protonpumpshämmare samt två olika antibiotikum. Forskning pekar på att probiotika har positiva effekter i behandling mot Helicobacter pylori. Syfte: Uppsatsen syftar till att undersöka och redogöra för om trippelterapibehandling i kombination med probiotika är en effektivare behandling hos patienter infekterade med Helicobacter pylori, än enbart trippelterapibehandling. Metod: Studien är designad som en litteraturstudie. I studien granskades sex stycken vetenskapliga, randomiserade, kliniskt prövade originalartiklar. Litteratursökningen genomfördes i databasen PubMed. Resultat: Fyra av studierna visade en signifikant skillnad mellan interventionsgruppen som tilldelats probiotika + trippelterapibehandling, och kontrollgruppen som enbart tilldelats trippelterapibehandling. Slutsats: Slutsatsen är att probiotika kombinerat med trippelterapibehandling är något effektivare än enbart trippelterapibehandling. För- och efterbehandling med probiotika i samband med en trippelterapibehandling gav störst effekt. Ytterligare studier krävs för att säkerställa effekten av probiotika vid en trippelterapibehandling. / Background: Being infected by Helicobacter pylori is very common all around the world. Research indicates that low socioeconomic status, overcrowding and bad hygiene most likely increases the risk of being infected by Helicobacter pylori. Helicobacter pylori infects the stomach and/or duodenal mucosa, which can result in a gastric ulcer and gastritis. Therefore, treatment should be instituted directly after Helicobacter pylori has been detected, to reduce the risk of developing gastric cancer. Treatment for a infection caused by Helicobacter pylori often involves a triple therapy treatment consisting of a proton-pump inhibitor and two different types of antibiotics. Research indicates that probiotics could have positive effects regarding treatment against Helicobacter pylori. Aim: The aim of this study is to examine if triple therapy treatment in combination with probiotics is a more effective treatment for patients infected by Helicobacter pylori, than with triple therapy treatment alone. Method: This study is designed as a literature study. Six different scientific, randomized, clinically tested original articles were examined. The literature search was conducted in the database PubMed. Result: There was a significant difference in four studies between the intervention group, which was assigned probiotics + triple therapy, and the control group, which was assigned only triple therapy treatment. Conclusion: The conclusion is that probiotics combined with triple therapy treatment is somewhat more effective than triple therapy treatment alone. A treatment with probiotics before and after a treatment with triple therapy treatment gave the largest effect. Further studies are needed to ensure the effect of probiotics with a triple therapy treatment.

Das Gen für die Expression von Helicobacter pylori Urease wurde in das Genom von Salmonella typhi Ty21a (Typhoral() integriert. Der resultierende Stamm erhielt die Bezeichnung Salmonella typhi Ty21a(pDB1). Neun gesunden Probanden wurde Salmonella typhi Ty21a(pDB1) verabreicht. In der Kontrollgruppe erhielten drei gesunde Probanden Salmonella typhi Ty21a. Schwerwiegende Nebenwirkungen wurden bei keinem der Probanden beobachtet. Zehn von 12 Probanden zeigten eine humorale Immunantwort gegen Antigene von Salmonella typhi, nachgewiesen über die Detektion spezifischer Antikörper produzierender Zellen, aber bei nur zwei Probanden ließ sich eine Serokonversion nachweisen. Eine zelluläre Immunantwort gegen das H-Antigen von Salmonella typhi konnte bei insgesamt fünf Probanden nachgewiesen werden. Insgesamt sechs Probanden zeigten eine zelluläre Immunantwort gegen Urease von Helicobacter pylori in zumindest einem von drei der zur Anwendung gebrachten Testsysteme (Proliferation, T-cell-Elispot, IFN-gamma Elisa). Eine humorale Immunantwort gegen Urease von Helicobacter pylori konnte bei keinem der Probanden nachgewiesen werden. Ty21a(pDB1) ist somit ein geeigneter Prototyp zur Optimierung einer Salmonella basierte Impfung zur Induktion einer zellulären Immunantwort, die zu einer protektiven Immunität gegenüber Helicobacter pylori führen könnte. / Helicobacter pylori urease was expressed in the common live typhoid vaccine Salmonella typhi Ty21a (Typhoral() yielding Salmonella typhi Ty21a(pDB1). Nine volunteers received Salmonella typhi Ty21a(pDB1) and three control volunteers received Salmonella typhi Ty21a. No serious adverse effects were observed in any of the volunteers. Ten out of 12 volunteers developed humoral immune responses to the Salmonella carrier as detected by antigen-specific antibody-secreting cells but only two volunteers seroconverted. A total of five volunteers showed cellular responses to the carrier. Six out of nine volunteers that had received Salmonella typhi Ty21a(pDB1) showed a T-cell response to Helicobacter urease in at least one of the three assays for detection of cellular response (Proliferation, T-cell-Elispot, IFN-gamma Elisa). No volunteer had detectable humoral responses to urease. Salmonella typhi Ty21a(pDB1) is a suitable prototype to optimize Salmonella-based vaccination for efficient cellular responses that could mediate protective immunity against Helicobacter.

Introdução: O envolvimento gastroduodenal pode ocorrer na doença de Crohn (DC). Seu diagnóstico histológico definitivo é habitualmente realizado através da demonstração do granuloma não caseoso. O achado de gastrite focal H. pylori negativa em biopsias gástricas de pacientes com DC ileal e/ou colônica, apesar de não ser específico, também sugere o envolvimento da doença neste segmento. Objetivos: avaliar a frequência da gastrite focal em pacientes com DC comparada à de pacientes com retocolite ulcerativa (RCU) e controles, assim como as frequências da infecção pelo H. pylori nessas populações e correlacioná-las com a presença de gastrite focal; avaliar a capacidade da imunohistoquímica em diferenciar a gastrite focal nos três grupos; avaliar as associações entre dados demográficos, aspectos clínicos, laboratoriais, uso de medicamentos, presença de sintomas do trato gastrintestinal (TGI) superior e achados endoscópicos com presença de gastrite focal em pacientes com doença inflamatória intestinal (DII); e avaliar a associação entre uso de medicamentos nesses pacientes e infecção pelo H. pylori. Métodos: Foram estudados 62 pacientes com DC, 35 pacientes com RCU e 40 pacientes controles. Todos foram submetidos à endoscopia digestiva alta (EDA) com biopsias para o teste da urease, exame histológico e imunohistoquímico. Resultados: Dos 137 pacientes estudados foram excluídos dois pacientes com DC e um com RCU. Não houve diferença estatisticamente significante entre os grupos com relação à idade (p=0,921) e sexo (p=0,192). A maioria dos pacientes com DC estava em remissão clínica (75%). Cerca de 80% dos pacientes com DC faziam uso de azatioprina. H. pylori foi positivo em 18/60 (30%) pacientes com DC, 12/34 (35%) na RCU e 20/40 (50%) no grupo controle sem diferença estatisticamente significante entre os grupos (p=0,131). Não foram observadas associações estatisticamente significantes entre uso de medicamentos e infecção pelo H. pylori nos pacientes com DII. A gastrite focal H. pylori negativa foi diagnosticada em 7/42 (16,7%) na DC, 3/22 (13,6%) na RCU e 2/20 (10%) no grupo controle, sem diferença estatisticamente significante entre eles (p=0,919). A gastrite focal H. pylori positiva foi diagnosticada em 2/18 (11%) na DC, 3/12 (25%) na RCU e 7/20 (35%) no grupo controle, sem diferença estatisticamente significante (p=0,213). Não foram observadas associações estatisticamente significantes entre características clínicas, laboratoriais, uso de medicamentos, sintomas do TGI superior, achados endoscópicos e gastrite focal. No entanto, foi observado que o uso de azatioprina nos pacientes com DC H. pylori negativos apresentou uma tendência a reduzir a gastrite focal. A imunohistoquímica da gastrite focal dos pacientes com DC e RCU H. pylori negativos foi semelhante e diferiu do grupo controle por este apresentar um maior acúmulo de linfócitos B (CD20). Já a imunohistoquímica da gastrite focal dos pacientes com DC, RCU e controles H. pylori positivos foi indistinguível. Conclusões: Pacientes com DII tendem a ser menos infectados pela bactéria H. pylori. A frequência de gastrite focal H. pylori negativa diagnosticada em nosso estudo foi menor do que a descrita na literatura. O uso de imunossupressor (azatioprina) pode estar relacionado com tal achado / Introduction: Gastroduodenal involvement may occur in Crohns disease (CD). Definitive histological diagnosis of CD in the upper gastrointestinal (GI) tract normally relies on the demonstration of epitheloid granuloma which is considered the histological hallmark of gastric CD. If granulomas are absent, the description of focally enhanced gastritis (FEG) or focal active gastritis in gastric biopsies of patients with known ileal and/or colonic CD, although not exclusive to CD, suggests the involvement of the disease at this site. Objectives: To access the prevalence of FEG in CD patients compared with a group of ulcerative colitis (UC) and CD/UC-free controls, as well as the frequencies of H. pylori infection in those population and correlate them to the presence of FEG; evaluate the capacity of immunohistochemistry in differentiating FEG in the three groups; evaluate the correlation with demographic and clinical characteristics, laboratory findings, current medical therapy as well as the presence of forgut symptoms and mucosal lesions at endoscopy with the presence or absence of FEG in patients with inflammatory bowel disease (IBD) and evaluate the association between medical therapy and H. pylori infection in IBD patients. Methods: We studied 62 patients with CD, 35 patients with UC and 40 patients from control group. All underwent upper GI endoscopy. Biopsy specimens taken from angulus, antrum and gastric body were evaluated by urease test, histology and immunohistochemistry. Results: Of the 137 patients studied we excluded 2 patients with CD and 1 with UC. There was no statistically significant difference among the groups in terms of age (p=0.921) and gender (p=0.192). The majority of CD patients were in clinical remission (75%). Around 80% of CD patients were taking azathioprine. H. pylori was positive in 18/60 (30%) CD patients, in 12/34 (35%) UC and in 20/40 (50%) controls with no statistically significance difference among the groups (p=0.131). No association was found between use of medications and H. pylori infection in IBD patients. In H. pylori negative patients, FEG was diagnosed in 16.7% cases (7/42) of CD, compared with 13.6% (3/22) of UC patients and 10% (2/20) of controls, with no statistically significance difference among them (p=0.919). In H.pylori positive patients, FEG was diagnosed in 11% cases (2/18) of DC, 25% (3/12) in UC and 35% (7/20) of controls with no significant difference among them (p=0.213). There was no statistical interrelationship between FEG and demographic and clinical characteristics, laboratory findings, use of medications, upper GI symptoms and endoscopic findings. However, it was observed that use of azathioprine in H. pylori negative CD patients presented a tendency to reduce FEG. In H. pylori negative patients, immunohistochemistry of FEG of CD and UC was similar and differed from controls as it presented a higher accumulation of B lymphocytes (CD20). On the other hand in H. pylori positive IBD patients, immunohistochemistry of FEG was indistinguishable from controls. Conclusions: IBD patients tend to be less infected by H. pylori. The frequency of H. pylori negative FEG diagnosed in our study was lower than described in literature. The use of immunossupressants (azathioprine) may be related to such findings

No Brasil, cerca de 65% da população é infectada por H. pylori, bactéria associada à patogênese de gastrite, úlcera péptica e considerada fator de risco de câncer gástrico. A transmissão da bactéria parece ocorrer de pessoa para pessoa, nas formas oral-oral, gástrica-oral e fecal-oral, e a cavidade bucal pode ser importante neste processo de transmissão. Os objetivos deste estudo foram: pesquisar a presença de H. pylori na cavidade bucal de pacientes dispépticos e identificar as possíveis cepas existentes. Para tanto, 43 pacientes com dispepsia funcional do Ambulatório de Estômago do Departamento de Gastroenterologia, Disciplina de Gastroenterologia Clínica FMUSP foram selecionados para o estudo. Todos realizaram exame de endoscopia digestiva alta e coleta de fragmento da mucosa gástrica para pesquisa de H. pylori através de teste da urease. A presença de H. pylori no estômago foi também evidenciada pelo teste respiratório com 14C ou sorologia, e em 30 pacientes foi identificado H. pylori no estômago. Foram coletadas 144 amostras da cavidade bucal: 43 de saliva, 43 de dorso de língua, 43 de placa supra-gengival e 15 de placa sub-gengival. A detecção de H. pylori das amostras bucais realizou-se através de PCR utilizando os primers espécie-específicos: P1/P2, Urease A/B e primers para investigar os genótipos cagA e vacA (m1, m2, s1a, s1b, s2). Não foi possível detectar o microorganismo em nenhuma amostra da cavidade bucal. Esse estudo mostrou que a cavidade bucal de pacientes dispépticos não representa reservatório para a bactéria. / Helicobacter pylori (H. pylori) infection is very prevalent in Brazil, infecting almost 65% of our population, being associated with peptic ulcer disease, gastric cancer, lymphoma and functional dyspepsia. The aim of this study was to evaluate the presence of this bacterium in the oral cavity of epigastric pain syndrome (functional dyspepsia) patients and assess the frequency of cagA and vacA genotypes of oral H. pylori. All 43 epigastric pain syndrome outpatients, who entered the study, were submitted to upper gastrointestinal endoscopy to rule out organic diseases. H. pylori infection was confirmed by rapid urease test, urea breath test and sorology, and thirty patients harbored H. pylori in the stomach. 144 samples of the oral cavity were collected: 43 samples of saliva, 43 of the tongue dorsum and 43 of supragingival dental plaque and 15 of sub-gingival dental plaque which were collected from the patients with periodontitis; H. pylori infection was verified by polymerase chain reaction (PCR) using primers (P1 and P2) that amplify the DNA sequence of a species-specific antigen present in all H. pylori strains, primers Urease A/B and primers for cagA and vacA (m1, m2, s1a, s1b, s2) genotyping. It was not possible to detect H. pylori in any oral samples using P1/P2 and Urease A/B. The genotype cagA was also negative in all samples and vacA genotype could not be characterized (s-m-). In this study, the oral cavity seemed not to be a reservoir for H. pylori in patients with epigastric pain syndrome being detected exclusively in the stomach.

published_or_final_version / Medicine / Master / Doctor of Medicine

Thesis (Ph. D.)--University of Texas Health Science Center at Houston, School of Public Health, 2007. / "May 2007" Includes bibliographical references (leaves 181-192).