title: A study of the upper gastrointestinal pH.
mesh_terms: D000368:Aged; D004386:Duodenum; D004566:Electrodes; D004947:Esophagus; D005260:Female; D005756:Gastritis / Q000378:metabolism; D005767:Gastrointestinal Diseases / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008722:Methods; D008875:Middle Aged; D010437:Peptic Ulcer / Q000378:metabolism; D013270:Stomach; D013272:Stomach Diseases / Q000378:metabolism; D013274:Stomach Neoplasms / Q000378:metabolism; D013686:Telemetry