Association of fasting breath nitrous oxide concentration with gastric juice nitrate and nitrite concentrations and Helicobacter pylori infection.

Fasting breath nitrous oxide (N2O) concentration was determined in relation to pH, nitrate (NO3-) and nitrite (NO2-) concentrations in gastric juice, and Helicobacter pylori infection in 86 successive patients. N2O was measured with an infrared-photoacoustic analyzer. NO3- and NO2- were measured using the Griess reaction. Fasting breath N2O concentration in controls (87 +/- 21 ppb) was not significantly different from that in patients with gastric ulcer or other gastric lesions. Breath N2O was significantly correlated with gastric NO3- (P < 0.01) and was higher in patients with elevated gastric NO2- (246 +/- 87 ppb) than in patients without NO2- (75 +/- 13 ppb). Breath N2O did not differ significantly between subjects who were positive or negative for H. pylori. In conclusion, fasting breath N2O concentration is in some manner related to intragastric NO3- and NO2- concentrations. The possible use of measuring breath N2O as predictors of cancer needs further research.