Esophageal pH MonitoringGastroesophageal RefluxEsophagusGastric Acidity DeterminationHydrogen-Ion ConcentrationProton Pump InhibitorsManometryCapsule EndoscopyGastric AcidEsophagoscopyStomachMonitoring, PhysiologicDuodenumPeptic UlcerMonitoring, AmbulatoryDuodenal DiseasesStomach DiseasesGastric MucosaGastric JuiceAntacidsAnti-Ulcer AgentsStomach UlcerDuodenal UlcerFamotidineHelicobacter pyloriRanitidineOmeprazoleHelicobacter InfectionsHistamine H2 AntagonistsDuodenogastric Reflux2-PyridinylmethylsulfinylbenzimidazolesGastritisPylorusDuodenitisLansoprazoleGastric EmptyingMagnesium HydroxideGastrinsGastric Outlet ObstructionEndoscopy, GastrointestinalDuodenoscopyPeptic Ulcer HemorrhageGastrointestinal MotilityPeptic Ulcer PerforationTechnetium Tc 99m DisofeninPyloric AntrumDuodenal ObstructionCimetidinePneumonia, AspirationGastrointestinal DiseasesGastrointestinal ContentsAnti-Inflammatory Agents, Non-SteroidalNaproxenDyspepsiaCross-Over StudiesRabeprazoleSucralfateGastrointestinal HemorrhagePreanesthetic MedicationVagotomy, TruncalStomach Neoplasms