Elena S.F. Berman - Mountain View CA, US John R. Speakman - Stonehaven, GB Manish Gupta - Mountain View CA, US Susan L. Fortson - Mountain View CA, US Douglas S. Baer - Menlo Park CA, US
Assignee:
LOS GATOS RESEARCH - Mountain View CA
International Classification:
G01J 3/42
US Classification:
356402
Abstract:
A method of measuring energy expenditure in a living subject comprises: (a) administering a specified dose of doubly-labeled water (HO) to a living subject; (b) obtaining samples at three or more times of body water from the living subject; (c) measuring H/H, O/O and O/O ratios in each of the obtained samples using optical spectroscopy; and (d) determining (1) a combined value of flux of body water and exhaled carbon dioxide from a change in measured O/O over time, (2) a value of flux of body water alone from a change in measured H/H over time, and (3) a reference value of isotopic background fluctuation from a change in measured O/O over time. Using O measurements to estimate background fluctuations of the H and O decreases the required isotope dosing of subjects or decreases uncertainty at current dosing levels.
Douglas Steven Baer - Menlo Park CA, US Elena Simone Franklin Berman - Mountain View CA, US Manish Gupta - Mountain View CA, US David A. Wagner - Nashua NH, US Daniel L. Bolt - Medford MA, US Susan Lauren Fortson - Mountain View CA, US
Assignee:
LOS GATOS RESEARCH - Mountain View CA
International Classification:
G01N 21/17 G01N 21/35 G01N 21/59
US Classification:
436127
Abstract:
Biological fluid samples containing proteins (e.g., blood plasma or saliva) are prepared for isotopic analysis by precipitating the proteins while leaving the isotopic ratio unaffected. This precipitation can involve adding metal ions, salts, organic solvents, or organic polymers. The sample is then centrifuged to allow transfer of the supernatant for isotopic analysis, e.g. by tunable diode laser absorption spectrometry to obtain a quantitative measure of the H and O isotope levels in the water relative to reference standards.
Montecito Elementary School Lafayette CA 1970-1977, Fairview Intermediate School Lafayette CA 1978-1979, Stanley Junior High School Lafayette CA 1978-1979