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Title: Measurement of /sup 2/H/sub 2/O by IR absorbance in doubly labeled H/sub 2/O studies of energy expenditure

Abstract

The energy expenditure of animals in their natural surroundings can be determined by measuring the turnover in body water of isotopes of oxygen and hydrogen. We evaluated the use of infrared spectrophotometry for measuring /sup 2/H/sub 2/O in small (20-microliters) water samples also labeled with 18O. For /sup 2/H/sub 2/O over the enrichment range of 0.1-1 atom%, there was a linear relationship between infrared absorbance and /sup 2/H/sub 2/O enrichment. /sup 2/H/sub 2/O enrichments could be measured with a precision and accuracy of less than or equal to 1%, using this relationship. The presence of /sup 18/O in water samples in enrichments of up to 1 atom% had no significant effect on measurement of /sup 2/H/sub 2/O by infrared absorbance. We measured the simultaneous turnover rates of /sup 2/H/sub 2/O and /sup 3/H in mice and turtles also labeled with 18O. Our results validated the use of infrared absorbance in doubly labeled water measures of energy expenditure and indicated that the fractionation factors in vivo for /sup 2/H/sub 2/O and /sup 3/H do not differ.

Authors:
; ;
Publication Date:
Research Org.:
Univ. of Wisconsin, Madison (USA)
OSTI Identifier:
6902005
Alternate Identifier(s):
OSTI ID: 6902005
Resource Type:
Journal Article
Resource Relation:
Journal Name: Am. J. Physiol.; (United States); Journal Volume: 255
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; BODY FLUIDS; INFRARED SPECTRA; METABOLISM; MEASURING METHODS; ACCURACY; ALGORITHMS; DEUTERIUM; DOUBLE LABELLING; MICE; OXYGEN 18; TRACER TECHNIQUES; TRITIUM COMPOUNDS; TURTLES; WATER; ANIMALS; BIOLOGICAL MATERIALS; EVEN-EVEN NUCLEI; HYDROGEN COMPOUNDS; HYDROGEN ISOTOPES; ISOTOPE APPLICATIONS; ISOTOPES; LABELLED COMPOUNDS; LABELLING; LIGHT NUCLEI; MAMMALS; MATERIALS; MATHEMATICAL LOGIC; NUCLEI; ODD-ODD NUCLEI; OXYGEN COMPOUNDS; OXYGEN ISOTOPES; REPTILES; RODENTS; SPECTRA; STABLE ISOTOPES; VERTEBRATES 550501* -- Metabolism-- Tracer Techniques

Citation Formats

Karasov, W.H., Han, L.R., and Munger, J.C. Measurement of /sup 2/H/sub 2/O by IR absorbance in doubly labeled H/sub 2/O studies of energy expenditure. United States: N. p., 1988. Web.
Karasov, W.H., Han, L.R., & Munger, J.C. Measurement of /sup 2/H/sub 2/O by IR absorbance in doubly labeled H/sub 2/O studies of energy expenditure. United States.
Karasov, W.H., Han, L.R., and Munger, J.C. Fri . "Measurement of /sup 2/H/sub 2/O by IR absorbance in doubly labeled H/sub 2/O studies of energy expenditure". United States. doi:.
@article{osti_6902005,
title = {Measurement of /sup 2/H/sub 2/O by IR absorbance in doubly labeled H/sub 2/O studies of energy expenditure},
author = {Karasov, W.H. and Han, L.R. and Munger, J.C.},
abstractNote = {The energy expenditure of animals in their natural surroundings can be determined by measuring the turnover in body water of isotopes of oxygen and hydrogen. We evaluated the use of infrared spectrophotometry for measuring /sup 2/H/sub 2/O in small (20-microliters) water samples also labeled with 18O. For /sup 2/H/sub 2/O over the enrichment range of 0.1-1 atom%, there was a linear relationship between infrared absorbance and /sup 2/H/sub 2/O enrichment. /sup 2/H/sub 2/O enrichments could be measured with a precision and accuracy of less than or equal to 1%, using this relationship. The presence of /sup 18/O in water samples in enrichments of up to 1 atom% had no significant effect on measurement of /sup 2/H/sub 2/O by infrared absorbance. We measured the simultaneous turnover rates of /sup 2/H/sub 2/O and /sup 3/H in mice and turtles also labeled with 18O. Our results validated the use of infrared absorbance in doubly labeled water measures of energy expenditure and indicated that the fractionation factors in vivo for /sup 2/H/sub 2/O and /sup 3/H do not differ.},
doi = {},
journal = {Am. J. Physiol.; (United States)},
number = ,
volume = 255,
place = {United States},
year = {Fri Jul 01 00:00:00 EDT 1988},
month = {Fri Jul 01 00:00:00 EDT 1988}
}
  • Energy expenditure before and after surgery was determined in seven patients by the doubly labeled water (/sup 2/H/sub 2//sup 18/O) method (DLW). The values were compared with values obtained by respiratory gas exchange by means of a metabolic measuring cart (MMC). Patients were maintained on total parenteral nutrition before and after trauma. The principal finding was an increase in the rate of CO/sub 2/ production of 11.9 +/- 5.0% after surgery. This corresponds to a 267 +/- increase in energy expenditure (p less than 0.05). No trauma-associated change in energy expenditure was found with the MMC. The correlation of preoperativemore » values from MMC and DLW was not statistically significant (r = 0.25), nor was the correlation of MMC and the Harris-Benedict equation, but the correlation of DLW with Harris-Benedict equation was statistically significant (r = 0.73, p less than 0.05). We suggest that the discrepancy is because the DLW method measures the cumulative energy expenditure over a period, whereas the MMC gives a spot measurement.« less
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  • A novel technique using a flowing afterglow-Langmuir probe apparatus for measurement of temperature dependences of rate constants for dissociative recombination (DR) is presented. Low ({approx}10{sup 11} cm{sup -3}) concentrations of a neutral precursor are added to a noble gas/electron afterglow plasma thermalized at 300-500 K. Charge exchange yields one or many cation species, each of which may undergo DR. Relative ion concentrations are monitored at a fixed reaction time while the initial plasma density is varied between 10{sup 9} and 10{sup 10} cm{sup -3}. Modeling of the decrease in concentration of each cation relative to the non-recombining noble gas cationmore » yields the rate constant for DR. The technique is applied to several species (O{sub 2}{sup +}, CO{sub 2}{sup +}, CF{sub 3}{sup +}, N{sub 2}O{sup +}) with previously determined 300 K values, showing excellent agreement. The measurements of those species are extended to 500 K, with good agreement to literature values where they exist. Measurements are also made for a range of C{sub n}H{sub m}{sup +} (C{sub 7}H{sub 7}{sup +}, C{sub 7}H{sub 8}{sup +}, C{sub 5}H{sub 6}{sup +}, C{sub 4}H{sub 4}{sup +}, C{sub 6}H{sub 5}{sup +}, C{sub 3}H{sub 3}{sup +}, and C{sub 6}H{sub 6}{sup +}) derived from benzene and toluene neutral precursors. C{sub n}H{sub m}{sup +} DR rate constants vary from 8-12 Multiplication-Sign 10{sup -7} cm{sup 3} s{sup -1} at 300 K with temperature dependences of approximately T{sup -0.7}. Where prior measurements exist these results are in agreement, with the exception of C{sub 3}H{sub 3}{sup +} where the present results disagree with a previously reported flat temperature dependence.« less
  • Reactions of water with M(CO){sub 3}(PR{sub 3}){sub 2} and M(CO){sub 3}(PR{sub 3}){sub 2}({eta}{sup 2}-H{sub 2}) (M = Mo, W; R= Cy (cyclohexyl), i-pr) have been studied in various organic solvents. The products contained reversibly bound H{sub 2}O, and infrared studies showed v(OH) modes at widely varying positions. IR of {sup 18}O-labeled complexes and {sup 1}H NMR gave no evidence for hydride or hydroxide ligands, indicating that oxidative addition of water did not occur. NMR of the aquo complexes showed rapid exchange between free and coordinated water at 298 K. The aquo complex W(C){sub 3}(P-i-Pr{sub 3}){sub 2}(H{sub 2}O){lg_bullet}THF was isolated frommore » THF and structurally characterized. A long W-O distance of 2.320 (5) A was observed for the reversibly bound H{sub 2}O ligand, which also undergoes hydrogen-bonding interactions with both lattice THF and a CO on an adjacent molecule. Water was found to instantaneously displace the dihydrogen ligand in W(CO){sub 3}(PR{sub 3}){sub 2}({eta}{sup 2}-H{sub 2}) in THF solution to give aquo complexes, but in hexane H{sub 2} remained bound under a H{sub 2} atmosphere. Thermodymanic measurements of the equilibrium W(CO){sub 3}(PR{sub 3}){sub 2}(H{sub 2}) + H{sub 2}O W(CO){sub 3}(PR{sub 3}){sub 2}(H{sub 2}O) + H{sub 2} in THF showed that the {Delta}H value for binding was 3-4 kcal/mol higher for H{sub 2}O. However, a higher entropy change related to hydrogen-bonding interactions between H{sub 2}O and solvent resulted in {Delta}G favoring H{sub 2} coordination at 25{degrees}C by 1-2 kcal/mol. Isotopic exchange of W(CO){sub 3}(P-i-Pr{sub 3}){sub 2}({eta}{sup 2}dD{sub 2}) with H{sub 2}O under a D{sub 2} atmosphere took place in THF, giving W(CO){sub 3}(P-i-Pr{sub 3}){sub 2}(D{sub 2}O). Both the favored binding of H{sub 2} versus H{sub 2}O and the latter exchange are relevant to the function of H{sub 2}-activating enzymes such as hydrogenase. 41 refs., 11 figs., 7 tabs.« less