title: A novel stable isotope breath test: 13C-labeled glycosyl ureides used as noninvasive markers of intestinal transit time.
abstract: OBJECTIVE
  Breath tests are widely used for diagnosis and control of treatment efficacy. There is a need for breath test substrates that reflect intestinal transit times under various conditions.
  
  
  METHODS
  We synthesized a new class of breath test substrates, 13C-labeled glycosyl ureides, which are specific markers for the action of colonic microbial flora. We then investigated their usefulness as markers of intestinal transit time.
  
  
  RESULTS
  Bolus ingestion of 1 g lactose or cellobiose 13C-ureide resulted in bacterial cleavage of the N-glycosyl bond and subsequent urea hydrolysis. 13CO2 appeared in breath and was determined by gas-isotope-ratio-mass spectrometry. Label first appeared after 5-6 h, peak excretion occurred between 8-14 h, and the signal returned to baseline after 18-24 h. Metoclopramide (10 mg) administered 1 h before the substrate advanced the onset of the signal by 2.4 +/- 1.95 h (mean +/- SD; n = 7; p < 0.05) and the time of peak response by 0.8 +/- 1.44 h. Loperamide (16 mg) broadened the peak and delayed the time of breath signal onset by 1.0 +/- 2.78 h and peak excretion by 4.0 +/- 3.7 h (p < 0.05).
  
  
  CONCLUSIONS
  The glycosyl ureide breath test reflected intestinal transit time and rapid changes in gastrointestinal motility. This test should be useful in the diagnosis of a variety of gastrointestinal motility disorders and in the development of drugs that affect gastrointestinal motility.
authors: USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas.
authors: W E
authors: WE
authors: Heine
authors: H K
authors: HK
authors: Berthold
authors: P D
authors: PD
authors: Klein
mesh_terms: D000293:Adolescent; D000328:Adult; D001944:Breath Tests / Q000379:methods*; D002245:Carbon Dioxide / Q000032:analysis*; D002250:Carbon Radioisotopes / Q000032:analysis / Q000652:urine; D005240:Feasibility Studies; D005260:Female; D005772:Gastrointestinal Transit / Q000187:drug effects / Q000502:physiology*; D006031:Glycosylation; D006801:Humans; D008139:Loperamide / Q000494:pharmacology; D008297:Male; D013058:Mass Spectrometry; D008787:Metoclopramide / Q000494:pharmacology; D008875:Middle Aged; D014508:Urea / Q000032:analysis*
chemical_list: D002250:Carbon Radioisotopes; D002245:Carbon Dioxide; D008139:Loperamide; D014508:Urea; D008787:Metoclopramide