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Diagnostic en médecine généraleBen Cheikh M'Hamed, Laurence. De Korwin, Jean-Dominique January 2003 (has links) (PDF)
Reproduction de : Thèse d'exercice : Médecine : Nancy 1 : 2003. / Titre provenant de l'écran-titre.
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Helicobacter pylori : molecular insights into regulation of adhesion propertiesGideonsson, Pär January 2016 (has links)
Helicobacter pylori infects the human stomach and triggers an inflammatory response that damages the gastric tissue. This host-pathogen interplay has dire consequences as up to 20 % of infected individuals develop peptic ulcer disease or gastric cancer. Given that half of the world’s population is infected, the number of afflicted humans is staggering and also tells that H. pylori is extremely efficient in spreading and maintaining infection. To enable persistent infection many factors play a role, but one important feature of H. pylori is its impressive ability to adhere to the slimy gastric mucus layer and the underlying epithelial cells. This occurs mainly via the BabA and SabA proteins that bind ABO/Leb- and sLex/sLea-antigens. I have in my thesis studied how these two proteins are utilized and regulated. H. pylori transcription is in part controlled by two-component systems (TCSs) that use a sensor protein and a DNA-binding response regulator. We have studied how these systems control sabA and to some extent babA and indeed found a better map of how sabA and babA is regulated at the transcriptional level. We also found that variations in a polynucleotide T-tract located in the sabA promotor could fine-tune SabA expression/ sLex-binding. Thus we have exposed how strict regulation by TCSs combined with stochastic processes together shapes attachment in the bacterial population. As the buffering mucus layer is constantly exfoliated, placing H. pylori in bactericidal acid, we hypothesized that low pH should abrogate adhesion. SabA expression was indeed repressed in low pH, however BabA expression remained unaffected. The BabA/ Leb-binding was instead directly reversibly hampered by low pH and the degree of pH sensitivity was strain dependent and encoded in the BabA sequence. We believe that the pH dependent loss of binding is one key factor H. pylori utilizes to maintain persistent infection. BabA is divided in generalists that bind ABO antigens and specialists that only bind blood group (bg) O. We co-crystalized BabA bound to these receptors and established the structural basis for generalist vs. specialist discrimination. We furthermore found a disulfide-clasped loop (CL2) in the center of the binding domain crucial for binding. Breaking CL2 with N-Acetylcysteine (NAC) disrupted binding and H. pylori infection mice experiments revealed inflammatory reduction upon NAC-treatment. In sum, I have in my thesis dissected how H. pylori controls its adhesive abilities and how intrinsic properties in binding can be exploited for therapeutic purposes.
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Comparative proteomic analyses of Helicobacter speciesFowsantear, Winita January 2013 (has links)
Helicobacter pylori infects and colonises in the human gastric where the infection can lead to gastric diseases. There are also a number of other Helicobacter species referred to as non-pylori Helicobacters that colonise other parts of the gastrointestinal tract. To understand those characteristics of the non-pylori Helicobacters that allow them to colonise different sites in the body resulting in different patterns of infection, the analysis of Helicobacter pylori and non-pylori Helicobacter proteomes was initiated. Total cellular proteins were extracted and compared using 2-DE. The Helicobacter proteome showed a high level of variability between different H. pylori strains as well as between the eight Helicobacter species analysed. It was proposed that some of the proteomic variation related to the pathogenic potential of the bacteria. Differential syntheses of specific proteins were found to be associated with H. pylori isolates associated with two different disease outcomes. Differential patterns of protein synthesis were also observed to discriminate between the Helicobacter isolates according to their site of colonisation defined as gastric and enterohepatic Helicobacter groups. Significant protein spots were identified by peptide fragment fingerprinting and LC-MS/MS. To provide additional functional information on the bacterial proteins, the Helicobacter hydrophobic proteins, which are typically located in the bacterial membrane and may be involved in bacterial host interactions, were analysed. Triton X-114 was used to enrich the bacterial hydrophilic and hydrophobic proteins which were analysed by 2-DE. There was significant enrichment of specific proteins to both the hydrophobic or hydrophilic fractions. Some of the enriched hydrophobic proteins which discriminated the Helicobacter species were identified. The Helicobacter species that colonise at different sites in the gastrointestinal tract are exposed to different acidic environments. The ability of the bacteria to survive the different levels of acid stress may contribute towards the observed proteomic variation. Quantitative differences in protein abundance were demonstrated between bacteria grown under neutral and acidic conditions. The differential patterns of protein synthesis were most clearly detected when the sub-cellular hydrophobic and hydrophilic fractions were analysed by 2-DE.
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Clinical aspects in Helicobacter pylori infectionsHouben, Martinus Henricus Maria Gerardus, January 2000 (has links)
Proefschrift Universiteit van Amsterdam. / Met lit. opg.
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Helicobacter pylori : bacterial diversity and human disease : microbiological and epidemiological studies with special reference to gastric cancer /Enroth, Helena, January 1900 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 6 uppsatser.
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The detection and characterisation of Helicobacter species in Australian marsupials /Coldham, Thosaporn. January 2004 (has links)
Thesis (Ph. D.)--University of New South Wales, 2004. / Also available online.
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Untersuchungen zur Regulation Motilitäts-assoziierter Gene in Helicobacter pyloriNiehus, Eike. January 2004 (has links)
Würzburg, Universiẗat, Diss., 2004. / Dateien im PDF-Format.
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TraG-like transporter proteins of type IV secretion systemsSchröder, Gunnar. January 2003 (has links)
Berlin, Freie University, Diss., 2003. / Dateiformat: zip, Dateien im PDF-Format.
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The role of DNA supercoiling in the coordinated regulation of gene expression in Helicobacter pyloriYe, Fang. January 2004 (has links) (PDF)
Würzburg, University, Diss., 2004.
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Helicobacter pylori colonization of the mouse gastric mucosa the Entner-Doudoroff pathway and development of a promoter-trapping system /Wanken, Amy Elizabeth, January 2004 (has links)
Thesis (Ph. D.)--Ohio State University, 2003. / Title from first page of PDF file. Document formatted into pages; contains xiii, 145 p.; also includes graphics (some col.). Includes abstract and vita. Advisor: Kathryn Eaton, Dept. of Veterinary Biosciences. Includes bibliographical references (p. 130-145).
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