GastritisGastric MucosaGastritis, AtrophicHelicobacter pyloriHelicobacter InfectionsMetaplasiaPyloric AntrumStomach NeoplasmsStomach UlcerStomachChronic DiseasePeptic UlcerPepsinogen AGastroscopyStomach DiseasesAchlorhydriaBiopsyGastric JuiceGastrinsDuodenal UlcerDyspepsiaBile RefluxPepsinogen CDuodenitisHelicobacterGastritis, HypertrophicHelicobacter heilmanniiUreaseIntestinal MucosaHelicobacter felisPrecancerous ConditionsParietal Cells, GastricCampylobacterAtrophyEndoscopy, GastrointestinalAnti-Ulcer AgentsAntigens, BacterialPepsinogensBacterial ProteinsAmoxicillinGastric AcidLymphoma, B-Cell, Marginal ZoneOmeprazoleMouth MucosaAntibodies, BacterialAnemia, PerniciousImmunohistochemistryDuodenumCampylobacter InfectionsH(+)-K(+)-Exchanging ATPaseLewis Blood-Group SystemPolymerase Chain ReactionClarithromycinPostgastrectomy SyndromesGastric FundusAdenocarcinomaCytotoxinsEndoscopyNasal MucosaChoristomaIntestinesGenotypeGastric MucinsHyperplasiaDuodenogastric RefluxEndoscopy, Digestive SystemMucous MembraneIntrinsic FactorImmunoglobulin GAcinonyxGastric Acidity DeterminationDNA, BacterialImmunoglobulin AAutoimmune DiseasesAnti-Bacterial AgentsCase-Control StudiesEpithelial CellsPathology Department, HospitalMicroscopy, ElectronDrug Therapy, CombinationDisease Models, AnimalPrevalenceEnzyme-Linked Immunosorbent AssayBismuthMexicoGastrin-Secreting CellsRisk FactorsRetrospective StudiesHistocytochemistryGerbillinaeSensitivity and SpecificityGene Rearrangement, B-Lymphocyte, Heavy ChainPentagastrin