GastritisGefarnateMetaplasiaStomach UlcerGastritis, AtrophicGastrointestinal HemorrhageHelicobacter pyloriGastric MucosaHelicobacter InfectionsPyloric AntrumGastritis, HypertrophicStomachGastroscopyPepsinogen AStomach NeoplasmsAchlorhydriaBile RefluxGastrinsPeptic UlcerPepsinogen CStomach DiseasesHigh-Throughput Nucleotide SequencingDuodenal UlcerHelicobacter felisHelicobacter heilmanniiChronic DiseaseParietal Cells, GastricDuodenitisAnemia, PerniciousDyspepsiaHelicobacterSequence Analysis, DNABiopsyUreasePepsinogensPostgastrectomy SyndromesGastric JuicePrecancerous ConditionsEndoscopy, Gastrointestinal