GastritisGastritis, AtrophicHelicobacter pyloriGastric MucosaHelicobacter InfectionsMetaplasiaChronic DiseaseStomach NeoplasmsPyloric AntrumStomach UlcerStomachPeptic UlcerPepsinogen AAchlorhydriaGastroscopyDyspepsiaDuodenitisDuodenal UlcerBiopsyPepsinogen CStomach DiseasesGastrinsHelicobacter heilmanniiBile RefluxHelicobacterGastric JuiceUreaseCampylobacterAtrophyHelicobacter felisPrecancerous ConditionsAntigens, BacterialEndoscopy, GastrointestinalGastritis, HypertrophicBacterial ProteinsLymphoma, B-Cell, Marginal ZoneAmoxicillinAnti-Ulcer AgentsCampylobacter InfectionsAntibodies, BacterialOmeprazoleClarithromycinLewis Blood-Group SystemCytotoxinsPolymerase Chain ReactionGenotypeDuodenumImmunohistochemistryAdenocarcinomaParietal Cells, GastricAnemia, PerniciousIntestinesGene Rearrangement, B-Lymphocyte, Heavy ChainMexicoDNA, BacterialImmunoglobulin GPepsinogensPostgastrectomy SyndromesHyperplasiaImmunoglobulin AAnti-Bacterial AgentsCase-Control StudiesInterleukin-1betaPrevalencePolymorphism, GeneticRisk FactorsDrug Therapy, CombinationEnzyme-Linked Immunosorbent AssayAcinonyx