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Calcium kinetics with microgram stable isotope doses and saliva sampling
S M Smith1, M E Wastney, L E Nyquist
1Biomedical Operations and Research Branch, NASA/Johnson Space Center, Houston, TX 77058, USA.
Journal of Mass Spectrometry : JMS
|November 1, 1996
Summary
This study demonstrates that calcium kinetics can be accurately assessed using microgram doses of stable isotopes and saliva samples. This approach reduces costs and minimizes the need for blood collection in calcium studies.
Area of Science:
- Biochemistry
- Physiology
- Analytical Chemistry
Background:
- Calcium kinetics studies traditionally use large tracer doses (mg) and frequent blood sampling.
- These methods can be costly and invasive, potentially perturbing the physiological system.
Purpose of the Study:
- To develop methods for estimating calcium kinetics using microgram (µg) stable isotope doses.
- To evaluate saliva as a non-invasive alternative to blood sampling for calcium kinetic analysis.
Main Methods:
- Administered oral 43Ca (133 µg) and intravenous 46Ca (7.7 µg) to subjects.
- Measured isotopic enrichment in blood, urine, saliva, and feces using thermal ionization mass spectrometry.
- Applied compartmental modeling to analyze kinetic parameters.
Main Results:
- Sufficient isotopic enrichment was detected up to 170 hours post-dosing.
- Fractional calcium absorptions derived from blood, urine, and saliva were comparable.
- Kinetic parameters estimated from serum and saliva data showed similarity.
Conclusions:
- Calcium kinetics can be reliably assessed using microgram stable isotope doses, reducing costs.
- Saliva sampling is a viable alternative to blood sampling, minimizing patient invasiveness.
