title: Paradox of gastric cardia: it becomes more acidic following meals while the rest of stomach becomes less acidic.
abstract: BACKGROUND
  The proximal cardia region of the stomach has a high incidence of inflammation, metaplasia and neoplasia. It demonstrates less acid buffering following meals than the more distal stomach. Novel high definition pHmetry was employed to investigate acidity at the cardia under fasting conditions and in response to a meal.
  
  
  METHODS
  15 healthy subjects were studied. A custom-made 12-electrode pH catheter was clipped at the squamocolumnar junction with four electrodes recording proximal to and eight distal to the squamocolumnar junction. The most distal pH electrode was located at the catheter tip, and nine electrodes in the region of the squamocolumnar junction were 11 mm apart.
  
  
  RESULTS
  The electrode situated in the cardia 5.5 mm distal to the squamocolumnar junction differed from all other intragastric electrodes during fasting in recording minimal acidity (pH <4 = 2.2%) while all other intragastric electrodes recorded high intragastric acidity (pH <4 =or>39%) (p<0.05). The cardia also differed from the rest of the stomach, showing a marked increase in acidity in response to the meal (from 2.2% fasting to 58.4% at 60-70 min after the meal; p<0.05) while the electrodes distal to the cardia all showed a marked decrease in acidity (p<0.05). These changes in acidity at the cardia following the meal caused the gastric acidity to extend 10 mm closer to the squamocolumnar junction.
  
  
  CONCLUSIONS
  Whereas the rest of the stomach shows a marked fall in acidity on ingesting a meal, the cardia paradoxically increases in acidity to become the most acidic region throughout the postprandial period.
authors.affiliation: Division of Cardiovascular and Medical Sciences, University of Glasgow, 44 Church Street, Western Infirmary, Glasgow G11 6NT, UK.
authors.forename: A T
authors.initials: AT
authors.lastname: Clarke
authors.forename: A A
authors.initials: AA
authors.lastname: Wirz
authors.forename: J P
authors.initials: JP
authors.lastname: Seenan
authors.forename: J J
authors.initials: JJ
authors.lastname: Manning
authors.forename: D
authors.initials: D
authors.lastname: Gillen
authors.forename: K E L
authors.initials: KE
authors.lastname: McColl
mesh_terms: D000328:Adult; D002299:Cardia / Q000378:metabolism / Q000502:physiology*; D004435:Eating / Q000502:physiology*; D016099:Endoscopy, Gastrointestinal; D050782:Esophageal pH Monitoring; D005215:Fasting / Q000502:physiology; D005260:Female; D005744:Gastric Acid / Q000378:metabolism / Q000502:physiology*; D005745:Gastric Acidity Determination / Q000295:instrumentation; D006801:Humans; D008297:Male; D008875:Middle Aged; D019518:Postprandial Period / Q000502:physiology*; D013272:Stomach Diseases / Q000378:metabolism / Q000503:physiopathology*; D055815:Young Adult