Metabolic Solutions offers project
design assistance and an analytical service to provide
direct measurement of extracellular water using sodium
bromide (NaBr) dilution space. Knowledge of extracellular
water provides a more complete understanding of body
composition as it relates to nutritional and health
status.
Alterations of body composition can often reveal adequacy
of nutritional support and the presence or progression
of disease. Total body water is often used to determine
body composition but is further divided into independently
varying compartments, intracellular water and extracellular
water. Variations in extracellular water can occur due
to poor nutrition, growth or disease and may not effect
changes in total body water.
Unlike most methods that employ radiolabels or require
expensive instrumentation, bromide offers a safe, inexpensive,
and accurate means to determine extracellular water.
Estimates of extracellular water using bromide dilution
space are easily adapted to determinations in human
infants, experimental animals, field studies, and applications
involving patients receiving critical care.
Bromide estimations of extracellular water do not alter
body composition and can be easily incorporated into
existing studies. For example, bromide sampling protocols
are compatible with the oxygen-18 or deuterium oxide
body composition technique thus determination of extracellular
water is easily accommodated.
Typical Extracellular Water Protocol
Orally administered bromide requires minimal preparation
and is inexpensive even for dosing of adults or large
animals. Experiments require collection of two blood
samples. Measurement of baseline is conducted prior
to dose administration and a second blood sample is
drawn after the dose has equilibrated. MSI's bromide
analysis service includes consultation for experimental
design and sample analysis.
Protocol for Estimating Extracellular Water Using
Sodium Bromide(NaBr)
- Draw 0.5-1ml baseline blood sample.
- Administer 30-60 mg/kg sodium bromide as a 5% solution
orally, intravenously, or subcutaneously.
- Wait for equilibration.
Equilibration requires 2 hours for IV, 4 hours for oral,
and 24 hours for subcutaneous administration.
- After equilibration draw second 0.5-1ml blood sample.
- Ship samples to MSI via an overnight service packaged with dry
ice.
Repeat measurements can be performed after 3-4 days.
Published Body Composition Studies Analyzed By Metabolic Solutions
1. Andrews, F.M., Nadeau, J.A., Saabye, L., Saxton, A.M. Measurement
of total body water in horses using deuterium oxide dilution. Am J Vet
Res 58(10):1060-1064, 1997.
"Deuterium oxide appears
safe and efficacious for determining total body water
content in horses and may be helpful for determining
changes in total body water content during exercise
and disease."
2. Armstrong, L.E., Kenefick, R.W., Castellani, J.W., Riebe, D., Kavouras,
S.A., Kuznicki, J.T., Maresh, C.M., Bioimpedance spectroscopy technique:
intra-, extracellular, and total body water., Medicine & Science
in Sports and Excerise, 29(12):1657-1663, 1997.
"The purpose of this
study was to test the validity of a multiple frequency
bioimpedance spectroscopy (BIS) technique that estimates
extracellular fluid volume (ECV), intracellular fluid
volume (ICV), and total body water (TBW)."
3. Cincotta, A.H., MacEachern, T.A., Meier, A.H. Bromocriptine redirects metabolism
and prevents seasonal onset of obese hyperinsulinemic state in Syrian hamsters.
Am. J. Physiol. 264(27):E285-E293, 1993.
"Metabolic and hormonal
effects of bromocriptine were studied in seasonally
obese female Syrian hamsters."
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