Nutritional assessment by isotope dilution analysis of body composition
The three components of body mass, body cell mass (BCM), extracellular fluid (ECF), and fat + extracellular solids (ECS: bone, tendon, etc) can be quantified using established isotope dilution techniques. With these techniques, total body water (TBW) and ECF are measured using 3H/sub 2/O and /sup 82/Bromine, respectively, as tracers. BCM is calculated from intracellular fluid (ICF) where ICF . TBW - ECF. Fat + ECS is estimated as: body weight - (BCM + ECF). TBW and ECF can be determined by either of two calculation methods, one requiring several timed plasma samples (extrapolation method) and one requiring a single plasma sample and a 4-h urine collection (urine-corrected method). The comparability of the two calculation methods was evaluated in 20 studies in 12 bone marrow transplant recipients. We found that for determination of TBW and ECF there was a very strong linear relationship (r2 greater than 0.98) between the calculation methods. Further comparisons (by t test, 2-sided) indicated that for the determination of ECF, the methods were not significantly (p greater than 0.90) different; however, TBW determined by the urine-corrected method was slightly (0.1 to 6%), but significantly (p less than 0.01) greater than that determined by the extrapolation method. Therefore, relative to the extrapolation method, the urine-corrected method ''over-estimates'' BCM and ''under-estimates'' fat + ECS since determination of these compartment sizes depends on measurement of TBW. We currently use serial isotope dilution studies to monitor the body composition changes of patients receiving therapeutic nutritional support.
- Research Organization:
- Cornell Univ., Ithaca, NY
- OSTI ID:
- 6136811
- Journal Information:
- Am. J. Clin. Nutr.; (United States), Vol. 40:4
- Country of Publication:
- United States
- Language:
- English
Similar Records
Nutritional assessment with body composition measurements
Measurement of total body water in human infants using deuterium isotope dilution and nuclear magnetic resonance spectroscopy
Related Subjects
BODY COMPOSITION
CHEMICAL ANALYSIS
NUTRITION
MONITORING
ADIPOSE TISSUE
BLOOD PLASMA
BODY FLUIDS
BROMINE 82
FAT CELLS
ISOTOPE DILUTION
PATIENTS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
URINE
ANIMAL CELLS
ANIMAL TISSUES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BIOLOGICAL WASTES
BLOOD
BODY
BROMINE ISOTOPES
CONNECTIVE TISSUE
CONNECTIVE TISSUE CELLS
DAYS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
MATERIALS
NUCLEI
ODD-ODD NUCLEI
RADIOISOTOPES
SOMATIC CELLS
TISSUES
WASTES
550601* - Medicine- Unsealed Radionuclides in Diagnostics