GastritisGastric MucosaHelicobacter pyloriHelicobacter InfectionsGastritis, AtrophicHelicobacterMetaplasiaStomach NeoplasmsStomachPyloric AntrumStomach UlcerChronic DiseasePeptic UlcerStomach DiseasesGastroscopyPepsinogen AUreaseHelicobacter heilmanniiDyspepsiaAchlorhydriaGastrinsGastric JuiceBiopsyDuodenitisPepsinogen CDuodenal UlcerAnti-Ulcer AgentsBile RefluxGastritis, HypertrophicAntigens, BacterialAmoxicillinIntestinal MucosaBacterial ProteinsPrecancerous ConditionsOmeprazoleEndoscopy, GastrointestinalParietal Cells, GastricHelicobacter felisCampylobacterClarithromycinAtrophyHelicobacter hepaticusAntibodies, BacterialPepsinogensGastric AcidLymphoma, B-Cell, Marginal ZoneLewis Blood-Group SystemPolymerase Chain ReactionMetronidazoleMouth MucosaDuodenumCampylobacter InfectionsAnemia, PerniciousBismuthH(+)-K(+)-Exchanging ATPaseCytotoxinsAnti-Bacterial AgentsImmunohistochemistryDNA, BacterialGastric FundusGastric Mucins2-PyridinylmethylsulfinylbenzimidazolesAdenocarcinomaPostgastrectomy SyndromesEndoscopyDrug Therapy, CombinationGenotypeLansoprazoleEndoscopy, Digestive SystemGerbillinaeImmunoglobulin GBreath TestsProton Pump InhibitorsIntestinesGastric Acidity DeterminationAcinonyxNasal MucosaEpithelial CellsChoristomaDuodenogastric RefluxHyperplasiaMolecular Sequence DataImmunoglobulin AEnzyme-Linked Immunosorbent AssayPrevalenceIntrinsic FactorCase-Control StudiesGastrointestinal DiseasesMucous MembraneAntacidsRanitidineRisk FactorsGastrin-Secreting CellsGastroesophageal RefluxMicroscopy, ElectronAutoimmune DiseasesTinidazoleEsophagitisProspective StudiesMexico