In vivo isotope-fractionation factors and the measurement of deuterium- and oxygen-18-dilution spaces from plasma, urine, saliva, respiratory water vapor, and carbon dioxide
In vivo isotope-fractionation factors were determined for hydrogen and oxygen between plasma water samples and samples of urine, saliva, respiratory water vapor, and carbon dioxide in 20 normal adults. The isotope-fractionation factors ranged from 0.944 to 1.039 for /sup 2/H in breath water vapor and for /sup 18/O in breath CO/sub 2/, respectively. When corrected for isotope fractionation, the /sup 2/H- and /sup 18/O-dilution spaces determined from urine, saliva, respiratory water, and CO/sub 2/ were within -0.10 +/- 1.09 kg (mean +/- SD, n = 60) and 0.04 +/- 0.68 kg (n = 80), respectively, of the values determined from plasma. In the absence of these corrections, we observed a 6% overestimation of /sup 2/H-dilution space and a 1% overestimation of /sup 18/O-dilution space from the use of respiratory water values. A 4% underestimation of the /sup 18/O-dilution space was observed for breath CO/sub 2/ without correction for isotope fractionation.
- Research Organization:
- Baylor College of Medicine, Houston, TX
- OSTI ID:
- 5471646
- Journal Information:
- Am. J. Clin. Nutr.; (United States), Vol. 47:1
- Country of Publication:
- United States
- Language:
- English
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BODY FLUIDS
ISOTOPE RATIO
CARBON DIOXIDE
DEUTERIUM
IN VIVO
ISOTOPE DILUTION
OXYGEN 18
PLASMA
SALIVA
URINE
BIOLOGICAL MATERIALS
BIOLOGICAL WASTES
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
EVEN-EVEN NUCLEI
HYDROGEN ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MATERIALS
NUCLEI
ODD-ODD NUCLEI
OXIDES
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
STABLE ISOTOPES
TRACER TECHNIQUES
WASTES
550201* - Biochemistry- Tracer Techniques