GastritisGastritis, AtrophicHelicobacter pyloriGastric MucosaHelicobacter InfectionsPyloric AntrumGastritis, HypertrophicMetaplasiaStomachGastroscopyPepsinogen AStomach NeoplasmsAchlorhydriaBile RefluxStomach UlcerGastrinsPeptic UlcerPepsinogen CStomach DiseasesDuodenal UlcerHelicobacter felisHelicobacter heilmanniiChronic DiseaseParietal Cells, GastricDuodenitisAnemia, PerniciousDyspepsiaBiopsyHelicobacterUreasePepsinogensPostgastrectomy SyndromesGastric JuicePrecancerous ConditionsEndoscopy, GastrointestinalCampylobacterAtrophyAcinonyxEndoscopyAnti-Ulcer AgentsAntigens, BacterialGastric AcidH(+)-K(+)-Exchanging ATPaseAmoxicillinAutoimmune DiseasesOmeprazoleDuodenogastric RefluxGastric FundusAntibodies, BacterialEndoscopy, Digestive SystemGastroenterostomyIntrinsic FactorGastric Acidity DeterminationBacterial ProteinsBismuthThymectomyCampylobacter InfectionsEsophagitisAntacidsLymphocytosisGastrointestinal DiseasesGastroesophageal RefluxGastrin-Secreting Cells