Exhaled NH3 and excreted Nh4+ in children in unpolluted or urban environments.
Exhaled ammonia (NH3ex) was measured by chemiluminescence in a group of healthy children (n = 20) and in two groups of asthmatic children, one (Group 1) residing in a National Park in the mountains (n = 68) and other (Group 2) in an urban area (n = 52). We also determined urinary ammonia, nitrates, urea, sodium and potassium normalized to osmolarity. Unlike exhaled nitric oxide (NOex), NH3ex was not specific to asthma as the children in Group 2 and the controls exhaled more ammonia that did the children in Group 1 (14.3 +/- 10.2 and 14.8 +/- 10.3 vs. 5.6 +/- 4.7 ppb; P < .001, respectively). In the urban environment, all children, including the healthy controls, excreted more ammonia (P < .001) and potassium (P < .001) but less urea (P < .02) than did the children residing in the National Park. These manifestations of moderate metabolic acidosis would favor excretion of ammonia at the expense of urea. In the children residing in the National Park, positive correlations were observed between NH3ex and urinary ammonia, and nitrates, age and morphological parameters. The relationship with the morphological parameters is a reflection of the normal physiological formation of NH3ex. In the children residing in the urban area, the other endogenous source of NH3ex was attributed to a slight disturbance in acid-base balance. In conclusion, the measurement of NH3ex appeared of limited interest, although the higher urinary urea/NH4+ ratio in Group 1 (P < .0001), especially in the treated children, appeared to be linked to the lack of atmospheric pollutants in the National Park. Further experimentation is in progress to confirm these findings.
Giroux
M
M
INSERM Unité 558 Epidémiologie el Analyses en Santé Publique: Risques, Maladies Chroniques et Handicaps, Hĵpital La Grave, Toulouse, France.
Brémont
F
F
Salles
J P
JP
Rey
E
E
Della Massa
J P
JP
Ferrières
J
J
D000393:Air Pollutants / Q000378:metabolism*; D000641:Ammonia / Q000378:metabolism*; D001249:Asthma / Q000378:metabolism*; D001944:Breath Tests; D016022:Case-Control Studies; D002648:Child; D004784:Environmental Monitoring / Q000379:methods; D005260:Female; D005602:France; D006801:Humans; D008163:Luminescent Measurements; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D009994:Osmolar Concentration; D011188:Potassium / Q000652:urine; D000644:Quaternary Ammonium Compounds / Q000652:urine*; D012423:Rural Health; D012964:Sodium / Q000652:urine; D013147:Spirometry; D014504:Urban Health; D014508:Urea / Q000652:urine
D000393:Air Pollutants; D000644:Quaternary Ammonium Compounds; D009569:Nitric Oxide; D000641:Ammonia; D014508:Urea; D012964:Sodium; D011188:Potassium