Esophageal pH MonitoringGastroesophageal RefluxEsophagusGastric Acidity DeterminationHydrogen-Ion ConcentrationProton Pump InhibitorsManometryEsophagoscopyDuodenogastric RefluxCapsule EndoscopyGastric AcidMonitoring, PhysiologicMonitoring, AmbulatoryBile RefluxAntacidsGastric JuiceVesico-Ureteral RefluxAnti-Ulcer AgentsRanitidineOmeprazoleStomach2-PyridinylmethylsulfinylbenzimidazolesFamotidineHistamine H2 AntagonistsEsophagitis, PepticLansoprazoleMagnesium HydroxideLaryngopharyngeal RefluxTechnetium Tc 99m DisofeninPneumonia, AspirationRabeprazoleGastrinsGastric MucosaCimetidineGastrointestinal ContentsGastric EmptyingImino AcidsCross-Over StudiesHeartburnEsophagitisVenous Insufficiency