GastritisGastritis, AtrophicHelicobacter pyloriGastric MucosaHelicobacter InfectionsMetaplasiaChronic DiseasePyloric AntrumStomach NeoplasmsStomachStomach UlcerPepsinogen APeptic UlcerGastroscopyAchlorhydriaDyspepsiaDuodenal UlcerPepsinogen CDuodenitisGastritis, HypertrophicBiopsyGastrinsBile RefluxStomach DiseasesHelicobacter heilmanniiHelicobacterGastric JuiceUreaseHelicobacter felisPrecancerous ConditionsCampylobacterAtrophyEndoscopy, GastrointestinalAntigens, BacterialAnti-Ulcer AgentsBacterial ProteinsAmoxicillinLymphoma, B-Cell, Marginal ZoneAntibodies, BacterialCampylobacter InfectionsOmeprazoleParietal Cells, GastricAnemia, PerniciousClarithromycinCytotoxinsPepsinogensLewis Blood-Group SystemPostgastrectomy SyndromesPolymerase Chain ReactionGenotypeDuodenumImmunohistochemistryAdenocarcinomaAcinonyxEndoscopyIntestinesGastric AcidH(+)-K(+)-Exchanging ATPaseImmunoglobulin GAutoimmune DiseasesDuodenogastric RefluxDNA, BacterialMexicoGastric FundusHyperplasiaAnti-Bacterial AgentsImmunoglobulin AGene Rearrangement, B-Lymphocyte, Heavy ChainEndoscopy, Digestive SystemGastroenterostomy