Abb Research Ltd.

Los Gatos Research, Inc.

Susan Lauren Fortson

Manish P Gupta

Douglas Steven Baer

David A Wagner

Elena S F Berman

Daniel L Bolt

John R Speakman

Elena Simone Franklin Berman

Edward L Melanson, Jr

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 theH andO isotope levels in the water relative to reference standards.

Method for isotopic analysis of water in bodily fluids

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) measuringH/H,O/O andO/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 measuredO/O over time, (2) a value of flux of body water alone from a change in measuredH/H over time, and (3) a reference value of isotopic background fluctuation from a change in measuredO/O over time. UsingO measurements to estimate background fluctuations of theH andO decreases the required isotope dosing of subjects or decreases uncertainty at current dosing levels.

Triple isotope method and analyzer for total energy expenditure measurements

Growing community of inventors

Mountain View, CA, United States of America

Susan Lauren Fortson