Introdução: Helicobacter pylori é uma bactéria que infecta aproximadamente metade da população mundial e é considerada uma importante causa de câncer gástrico. A terapia de erradicação nem sempre é eficaz, pois pode ocorrer a resistência aos antimicrobianos. Objetivo: Determinar o perfil de sensibilidade de isolados de H. pylori frente aos antibióticos amoxicilina, claritromicina e ciprofloxacina na população do Rio Grande do Sul empregando distintas padronizações. Material e Métodos: Estudo transversal. Avaliaram-se 54 amostras de H. pylori obtidas através de cultivo de biópsias gástricas em Agar Belo Horizonte e incubação a 37°C em microaerofilia, durante cinco dias. A sensibilidade aos antibióticos foi determinada segundo as orientações das padronizações britânica (BSAC) e australiana (CDS Method) (quantitativas), além da francesa (CA-SFM) (qualitativa). Resultados e discussão: Sete (13%) isolados de H. pylori foram resistentes à claritromicina, um (1,9%) à amoxicilina e três (5,5%) à ciprofloxacina. Estes índices de resistência são considerados satisfatórios e demonstram que todos esses antibióticos podem ser utilizados na terapia empírica na população local, sobretudo a amoxicilina e a claritromicina como primeira linha de tratamento. As metodologias quantitativas BSAC e CDS Method revelaram concordância muito semelhante nos resultados de sensibilidade, sendo a interpretação mais facilitada na técnica CDS Method. A padronização CA-SFM parece ser mais atrativa sob o aspecto econômico, mas fornece resultados apenas qualitativos. Conclusão: Os antibióticos amoxicilina e claritromicina ainda são uma boa opção no tratamento anti-H. pylori na população do Rio Grande do Sul. / Introduction: Helicobacter pylori is a bacteria which infects nearly half the world population and it is considered an important cause of gastric cancer. The eradication therapy is not always effective because resistance to antimicrobials may occur. Objective: To determine the susceptibility profile of H. pylori isolates to the antibiotics amoxicillin, clarithromycin and ciprofloxacin in the population of Rio Grande do Sul using different standardizations. Material and Methods: Transversal study. Were evaluated 54 samples of H. pylori obtained by gastric biopsies which were cultured on Belo Horizonte agar and incubated at 37°C in a microaerophilic environment for five days. The antibiotics susceptibility was determined according to the guidelines of the British Society for Antimicrobial Chemotherapy (BSAC), the Australian (CDS Method) (quantitative) and the French (CA-SFM) (qualitative). Results and discussion: Seven (13%) H. pylori isolates were resistant to clarithromycin, one (1,9%) to amoxicillin and three (5,5%) to ciprofloxacin. These indices of resistance are considered satisfactory and show that all of these antibiotics can be used in the empirical therapy of the local population, especially amoxicillin and clarithromycin as a first line treatment. The quantitative methodologies BSAC and CDS Method revealed very similar agreement in the susceptibility results. Moreover, the CDS method had an easier interpretation technique. The CA-SFM standards seem to be more attractive on the economic aspect but they only provide qualitative results. Conclusion: The antibiotics amoxicillin and clarithromycin are still a good option for anti-H. pylori treatment in the population of Rio Grande do Sul.

Introdução: Helicobacter pylori é uma bactéria que infecta aproximadamente metade da população mundial e é considerada uma importante causa de câncer gástrico. A terapia de erradicação nem sempre é eficaz, pois pode ocorrer a resistência aos antimicrobianos. Objetivo: Determinar o perfil de sensibilidade de isolados de H. pylori frente aos antibióticos amoxicilina, claritromicina e ciprofloxacina na população do Rio Grande do Sul empregando distintas padronizações. Material e Métodos: Estudo transversal. Avaliaram-se 54 amostras de H. pylori obtidas através de cultivo de biópsias gástricas em Agar Belo Horizonte e incubação a 37°C em microaerofilia, durante cinco dias. A sensibilidade aos antibióticos foi determinada segundo as orientações das padronizações britânica (BSAC) e australiana (CDS Method) (quantitativas), além da francesa (CA-SFM) (qualitativa). Resultados e discussão: Sete (13%) isolados de H. pylori foram resistentes à claritromicina, um (1,9%) à amoxicilina e três (5,5%) à ciprofloxacina. Estes índices de resistência são considerados satisfatórios e demonstram que todos esses antibióticos podem ser utilizados na terapia empírica na população local, sobretudo a amoxicilina e a claritromicina como primeira linha de tratamento. As metodologias quantitativas BSAC e CDS Method revelaram concordância muito semelhante nos resultados de sensibilidade, sendo a interpretação mais facilitada na técnica CDS Method. A padronização CA-SFM parece ser mais atrativa sob o aspecto econômico, mas fornece resultados apenas qualitativos. Conclusão: Os antibióticos amoxicilina e claritromicina ainda são uma boa opção no tratamento anti-H. pylori na população do Rio Grande do Sul. / Introduction: Helicobacter pylori is a bacteria which infects nearly half the world population and it is considered an important cause of gastric cancer. The eradication therapy is not always effective because resistance to antimicrobials may occur. Objective: To determine the susceptibility profile of H. pylori isolates to the antibiotics amoxicillin, clarithromycin and ciprofloxacin in the population of Rio Grande do Sul using different standardizations. Material and Methods: Transversal study. Were evaluated 54 samples of H. pylori obtained by gastric biopsies which were cultured on Belo Horizonte agar and incubated at 37°C in a microaerophilic environment for five days. The antibiotics susceptibility was determined according to the guidelines of the British Society for Antimicrobial Chemotherapy (BSAC), the Australian (CDS Method) (quantitative) and the French (CA-SFM) (qualitative). Results and discussion: Seven (13%) H. pylori isolates were resistant to clarithromycin, one (1,9%) to amoxicillin and three (5,5%) to ciprofloxacin. These indices of resistance are considered satisfactory and show that all of these antibiotics can be used in the empirical therapy of the local population, especially amoxicillin and clarithromycin as a first line treatment. The quantitative methodologies BSAC and CDS Method revealed very similar agreement in the susceptibility results. Moreover, the CDS method had an easier interpretation technique. The CA-SFM standards seem to be more attractive on the economic aspect but they only provide qualitative results. Conclusion: The antibiotics amoxicillin and clarithromycin are still a good option for anti-H. pylori treatment in the population of Rio Grande do Sul.

Introdução: Helicobacter pylori é uma bactéria que infecta aproximadamente metade da população mundial e é considerada uma importante causa de câncer gástrico. A terapia de erradicação nem sempre é eficaz, pois pode ocorrer a resistência aos antimicrobianos. Objetivo: Determinar o perfil de sensibilidade de isolados de H. pylori frente aos antibióticos amoxicilina, claritromicina e ciprofloxacina na população do Rio Grande do Sul empregando distintas padronizações. Material e Métodos: Estudo transversal. Avaliaram-se 54 amostras de H. pylori obtidas através de cultivo de biópsias gástricas em Agar Belo Horizonte e incubação a 37°C em microaerofilia, durante cinco dias. A sensibilidade aos antibióticos foi determinada segundo as orientações das padronizações britânica (BSAC) e australiana (CDS Method) (quantitativas), além da francesa (CA-SFM) (qualitativa). Resultados e discussão: Sete (13%) isolados de H. pylori foram resistentes à claritromicina, um (1,9%) à amoxicilina e três (5,5%) à ciprofloxacina. Estes índices de resistência são considerados satisfatórios e demonstram que todos esses antibióticos podem ser utilizados na terapia empírica na população local, sobretudo a amoxicilina e a claritromicina como primeira linha de tratamento. As metodologias quantitativas BSAC e CDS Method revelaram concordância muito semelhante nos resultados de sensibilidade, sendo a interpretação mais facilitada na técnica CDS Method. A padronização CA-SFM parece ser mais atrativa sob o aspecto econômico, mas fornece resultados apenas qualitativos. Conclusão: Os antibióticos amoxicilina e claritromicina ainda são uma boa opção no tratamento anti-H. pylori na população do Rio Grande do Sul. / Introduction: Helicobacter pylori is a bacteria which infects nearly half the world population and it is considered an important cause of gastric cancer. The eradication therapy is not always effective because resistance to antimicrobials may occur. Objective: To determine the susceptibility profile of H. pylori isolates to the antibiotics amoxicillin, clarithromycin and ciprofloxacin in the population of Rio Grande do Sul using different standardizations. Material and Methods: Transversal study. Were evaluated 54 samples of H. pylori obtained by gastric biopsies which were cultured on Belo Horizonte agar and incubated at 37°C in a microaerophilic environment for five days. The antibiotics susceptibility was determined according to the guidelines of the British Society for Antimicrobial Chemotherapy (BSAC), the Australian (CDS Method) (quantitative) and the French (CA-SFM) (qualitative). Results and discussion: Seven (13%) H. pylori isolates were resistant to clarithromycin, one (1,9%) to amoxicillin and three (5,5%) to ciprofloxacin. These indices of resistance are considered satisfactory and show that all of these antibiotics can be used in the empirical therapy of the local population, especially amoxicillin and clarithromycin as a first line treatment. The quantitative methodologies BSAC and CDS Method revealed very similar agreement in the susceptibility results. Moreover, the CDS method had an easier interpretation technique. The CA-SFM standards seem to be more attractive on the economic aspect but they only provide qualitative results. Conclusion: The antibiotics amoxicillin and clarithromycin are still a good option for anti-H. pylori treatment in the population of Rio Grande do Sul.

Les systèmes Toxine Antitoxine (TA) sont présents chez la plupart des génomes bactériens. Nous rapportons dans cette étude la présence de tels systèmes chez la bactérie pathogène Helicobacter pylori. Ce nouveau système TA de type I, de la même manière que les autres systèmes de type I décrits, est composé d’une toxine peptidique membranaire (AapA) dont la traduction est inhibée par un ARNnc (IsoA) suivant une interaction côté 5’ non traduit de l’ARNm. La structuration particuliere de l’ARNm a permit l’identification d’orthologue de ce système dans les chromosomes des genres Helicobacter et Campylobacter mais aussi sur leur patrimoine génétique mobiles, tels les plasmides. Ceci impliquant leur potentielle acquisition dans le génome par transfert génétique horizontal. La deuxième partie de l’étude se focalise sur la résolution par RMN du liquide de la structure atomique de la toxine AapA1 dans un environnement pseudo-membranaire. Une approche par mutation révèle les determinants structuraux de la toxicité, pointant la présence d’une empreinte de charge dans la partie helicoidale transmenbranaire de la toxine présente aussi chez d’autres toxines de Type I. La dernière partie de l’étude se centre sur l’expression et la purification de la toxine afin d’en étudier la structure en environnement membranaire complexe par RMN du solide. Les résultats prometteurs ouvrent la voie à une caractérisation de la toxine par l’expérience de PISEMA. / Toxin-antitoxin (TA) systems are present in almost all bacterial genomes. Here we report that the genome of the major human gastric pathogen, Helicobacter pylori, is hosting several copies of a new family of type I TA systems. Similarly to other type I TA systems, the toxin (AapA) is a small membrane protein whose expression is controlled by a small antisense RNA (IsoA, antitoxin) that binds to the 5’ untranslated region (UTR) of the mRNA. In addition we used the strong conservation of the mRNA folding to identify homologs of this TA system not only in other Helicobacter and Campylobacter chromosomes but also on plasmids, indicating that this new TA system might have been spread over different genomes via horizontal gene transfer.The second part of the study take account of the AapA toxin itself. We acutely determine the structure of AapA1 by liquid state NMR in membrane mimicking environment. We then probe first structural insight on atomic structural determinants of its toxicity following a mutation studies.These results reveal a particular charge pattern on the transmembrane α helix domain of AapA toxin similary to other Type I toxin. A third part of the studies is based on expression and purification of the toxin in order to determine the structure in complex membrane environment by solid state NMR. The promosisng result open the way to characterize the toxin by PISEMA experiment.

Les microARN sont de petits ARN non codant régulant post-transcriptionnellement l’expression de certains gènes. Du fait de leur fort potentiel régulateur, une modification de leur expression peut conduire à l’apparition de pathologies telles que le cancer ou l’inhibition des mécanismes de défense contre des pathogènes. Notre objectif est de caractériser le rôle de certains miARN dans la formation de cancer gastrique dû à Helicobacter pylori. En effet, cette bactérie peut conduire à l’apparition d’adénocarcinome gastrique et de lymphome du MALT. Sa virulence est essentiellement due à la protéine CagA, injectée dans les cellules de la muqueuse gastrique. Par séquençage à haut débit du contenu en miARN d’une lignée épithéliale gastrique humaine, co-cultivée ou non avec H. pylori, nous avons observé que les niveaux de miR-200b/c sont augmentés par l’infection. Ces miARN sont des inhibiteurs puissants de la transition épithélio-mésenchymateurse (TEM), modification morphologique promotrice d’invasion. Ils ciblent les facteurs de transcription ZEB1/2 avec lesquels ils sont impliqués dans une boucle de rétro-action mutuellement répressive. Le niveau basal élevé de miR-200b/c dans ces cellules réprime totalement ZEB1, tandis que l’infection par H. pylori, sous la dépendance de CagA, promeut une TEM en induisant ZEB1. Paradoxalement, les miR-200b/c sont aussi augmentés lors de l’infection transcriptionnellement. Nous avons pu démontrer que l’augmentation des miR-200b/c dans les cellules infectées a pour rôle de modérer l’induction de ZEB1 via l’activation de NF-kB, constituant ainsi un mécanisme de défense des cellules hôte contre la perte de leur identité épithéliale. / MicroRNA are small noncoding RNA that post-transcriptionally regulate gene expression. Due to their high regulator potential, a change in their expression may lead to the emergence of diseases such as cancer or inhibition of defense mechanisms against pathogens. Our aim is to characterize the role of miRNA in the response of gastric eptithelial cells to Helicobacter pylori (H. pylori). Indeed, H. pylori promote gastric adenocarcinoma and MALT lymphoma. Its virulence is essentially mediated by CagA, injected into cells of the gastric mucosa. Thanks to high throughput sequencing of miRNA content of a gastric epithelial cell line, infected or not with H. pylori: miR-200b and -200c appeared up-regulated upon infection. These miRNA are potent inhibitors of the “epithelial-to-mesenchymal transition” (EMT), a process that drastically alters cell morphology and promotes cell invasion. MiR-200b/c target the transcription factors ZEB1 and ZEB2, with which they are involved in a mutually repressive feedback loop. In basal conditions, the high levels miR-200b/c in gastric epithelial cells totally silence ZEB1 mRNA whereas H. pylori promotes EMT via ZEB1 expression, on the dependence of CagA translocation into host cells. But, paradoxically, miR-200b/c levels were also up-regulated upon infection. The increased miR-200b/c levels in infected cells moderate ZEB1 induction thanks to NF-kB activation and constitute a self-defense mechanism to thwart the loss of their epithelial phenotype upon infection.

Orientadores: José Murilo Robilotta Zeitune, Sandra Cecília Botelho Costa / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-18T12:37:01Z (GMT). No. of bitstreams: 1 Roesler_BrunaMaria_D.pdf: 2549394 bytes, checksum: 8534c8dd497e83d0a6b58932dcf0c4cf (MD5) Previous issue date: 2011 / Resumo: O entendimento acerca da carcinogênese gástrica, que é um processo multifatorial, avançou consideravelmente nas últimas décadas, especialmente no que diz respeito ao papel do Helicobacter pylori no desenvolvimento das lesões pré-cancerosas e na neoplasia propriamente dita, tanto em seu estágio precoce quanto avançado. O H. pylori é uma bactéria gram-negativa, classificada como carcinógeno tipo I pela IARC e que possui um alto grau de diversidade genética, assim como importantes fatores de virulência, o que pode ser verificado através das diferentes cepas encontradas nas doenças do trato gastrointestinal. A determinação, portanto, das cepas mais virulentas, responsáveis, pelo menos teoricamente, pelo desenvolvimento das doenças gástricas mais graves, é de vital importância tanto para estudos epidemiológicos quanto para a determinação de quais são os pacientes com maior probabilidade de desenvolvimento do câncer gástrico, que permanece como um grave problema de saúde pública. No presente estudo foram comparadas cepas da bactéria prevalentes em amostras de tecido gástrico provenientes de pacientes com diagnóstico de adenocarcinoma gástrico distal do tipo intestinal precoce e avançado através do uso de técnicas de biologia molecular para avaliar diferentes regiões genômicas da bactéria: genes ureaseC, vacA (regiões s e m), cagA, cagT e dupA (regiões jhp0917 e jhp0918). Os resultados obtidos foram semelhantes tanto para os casos precoces quanto avançados da doença, porém, uma relação estatisticamente significativa foi encontrada entre o gene cagA e o adenocarcinoma avançado. Em geral, as cepas foram classificadas como vacA s1m1, cagA positivas, cagT positivas e dupA negativas, concluindo-se que cepas com o genótipo vacA s1m1 cagA positivo e cagT positivas podem ser consideradas mais virulentas. Além disso, conclui-se que o gene dupA, apesar de pouco presente nas amostras de câncer gástrico estudadas, não pode ser considerado um marcador exclusivo da úlcera duodenal, como descrito inicialmente / Abstract: The understanding of gastric carcinogenesis, that is a multifactorial process, has advanced considerably in recent decades, especially with regard to the role of Helicobacter pylori in the development of precancerous lesions and cancer, both in its early or advanced stage. H. pylori is a gram-negative bacteria, classified as a group I carcinogen by the IARC and it has a high degree of genetic diversity, as well as important virulence factors, which can be verified through the different strains present in gastrointestinal diseases. Therefore, determination of the most virulent strains, responsible, at least theoretically, for the development of the most severe diseases, as gastric adenocarcinoma, is of fundamental importance for epidemiological studies and for determination of the patients with high probability for development of the disease, which remains as a serious public health problem. In the present study they were compared strains of the bacteria prevalent in early and advanced gastric distal type intestinal adenocarcinoma through molecular biology techniques to evaluate different regions of bacterium genoma: urease C, vacA (regions s and m), cagA, cagT and dupA (jhp0917 and jhp0918 regions) genes. The results were similar for both early and advanced cases of the disease, however, a statistically significant relationship was found between the cagA gene and advanced adenocarcinoma. In general, the strains were classified as vacA s1m1, cagA positive, cagT positive and dupA negative, conducting that strains with the genotype vacA s1m1, cagA positive and cagT positive may be considered more virulent. Moreover, it is concluded that the dupA gene, although found in a little proportion of the gastric cancer H. pylori strains, can not be considered an exclusive marker for duodenal ulcer, as described earlier / Doutorado / Ciencias Basicas / Doutor em Clínica Médica

No description available.

Infection with the gut-pathogen Helicobacter pylori is the single, most important risk factor in the development of gastric cancer. Although there is a rising incidence in mortality resulting from this malignancy, the exact mechanism underlying the initiation and progression of bacterial-induced gastric tumorigenesis is still not completely understood. Several studies implicate the activation of the Signal Transducer and Activator of Transcription 3 (STAT3) signaling pathway as a cellular trigger for promoting carcinogenes. In this thesis, I studied the role of the STAT3 signaling pathway in H. pylori mediated tumorigenesis, and attempted to delineate mechanisms involved. I have found that H. pylori activates the STAT3 signaling pathway both in vitro and in vivo, to promote carcinogenesis. Pivotal for H. pylori mediated STAT3 activation are the bacterial effector protein CagA and host receptor components, the gp130 and the IL-6αR subunits. Further investigation into the mechanism of STAT3 induction identified a key role for cholesterol-enriched membrane lipid rafts. Bacterial invasion and CagA injection into host cells was also dependent on lipid raft integrity. Co-fractionation via the use of sucrose gradients, which permits the isolation of lipid rafts, identified H. pylori CagA to be associated with these membrane microdomains. CagA, once injected into the cell, appears to interact with the inner leaflet of the host plasma membrane via a charge association that either directly or indirectly anchors it to the negatively charged anionic lipids in the cytoplasmic membrane. In addition, janus kinases were recruited to rafts upon H. pylori infection. In this thesis, I present a dynamic model of STAT3 activation, which requires the interaction of lipid raft associated proteins, H. pylori CagA and recruited JAKs with non-lipid raft receptor components to support STAT3 signaling. This study is significant since it provides insight into the possible mechanisms by which H. pylori induces gastric cancer and furthermore, it facilitates the development of novel therapeutic targets directed against bacterial induced carcinogenesis.

OBJETIVO: Presentar un estudio donde se buscará al Helicobacter pylori como factor asociado en la aparición de ulceras pépticas. FINALIDAD: Se busca con el presente estudio contar con una base de datos actual para poder tomar medidas sanitarias en el distrito de Vitarte. MÉTODO: Estudio analítico de tipo caso-control, con una muestra de 264 donde 132 casos y de 132 controles. MATERIALES: Se realiza una revisión de historias clínicas, mediante una ficha se recolecta la información y se procesa en la basas de datos SPSS y EXCEL. RESULTADOS: El Helicobacter pylori tuvo un OR 4.3 (IC 95 % 2,29 -8,11) y una prevalencia de 81%. La prevalencia del sexo femenino fue de 61%. La prevalencia de los casados fue de 42% y la prevalecía de pacientes sin Helicobacter pylori y con una cruz fue de 39%. CONCLUSIONES: El Helicobacter pylori es una factor asociado a la presencia de ulceras pépticas.

Diverse extracellular stimuli, including ultraviolet light, irradiation, heat shock, proinflammatory cytokines, trigger activation of MAPK pathway through phosphorylation on a TGY motif within the kinase activation loop. Protein MAPK appears to play a major role in apoptosis. It has been causally implicated in sepsis and arthritis. The translational small ubiquitin related modifier (SUMO) modification of proteins has been shown to play multiple functional roles in several cellular processes, including signal transduction, protein targeting, stabilization, transcriptional activation and apoptosis. Our previous study demonstrated that the expression levels of SUMO-1 rnRNA and proteins were enhanced in Helicobacter pylori infected human gastric epithelial cells. The activation of MAPK pathway and cellular apoptosis of AGS cell lines were increased during Helicobacter pylori infection. It was hypothesized that Helicobacter pylori functioning as a biological stress that induced MAPK mediated apoptosis which may be regulated by sumoylation. Results showed that MAPK phosphorylation and cellular apoptosis were enhanced in RFP-SUMOs or GFP-MAPK expressing cells, especially during Helicobacter pylori infection. It was inhibited by pretreatment of MAPK inhibitor. The enhanced phosphorylation and apoptosis were observed during GFP-MAPK overexpression. It¡¦s suggested that MAPK is a target protein for SUMOs.