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Comparison of electrical impedance and anthropometric measurement of upper arm muscle and fat area
p.60
A SENSITIVE METHOD FOR MEASURING NUTRIENT OXIDATION BY COMBINED INDIRECT CALORIMETRY AND STABLE ISOTOPIC LABELLING. P.J.Garlick, K.C.McHardy, M.A.McNurlan, A.G.Calder, J.D.Digweed, L.M.Fearns, J.Broom (The Rowett Research Institute and Aberdeen University Medical School, Aberdeen, Scotland) The nature of the substrates being oxidised by the body can, in theory, be determined if the respiratory gas exchange is measured. The calculations, however, require an independent estimate of the rate of protein oxidation. In chronic experiments it has been considered satisfactory to estimate the rate of protein oxidation from the urinary nitrogen excretion, but this is not suitable when rapid15hanges in oxidation occur, as when postabsorptive subjects are refed. We have used ( C)leucine to measure the rapid reflected by increase in amino acid oxidation on feeding, which is not nitrogen excretion. Five overnight-fasted Respiratory gases were monitored continuously oj?Sieucine oxidation were derived from the enrichment of plasma keto-isocaproate at occurred with feeding on cant731 days when no substantial rise in CO enrichment tiz the recovery of infused ( C)bicarbonate isotope was given. was found to be 72% fasted and 89% fed. Leucine was taken to be 8% of protein oxidation in both fed and fasted states and rates were calculated from data collected during the last 2 h of the fasted and fed periods. Protein oxidation rose rapidly from 33 + 6 mg/kg/h (mean _+SD) during fasting to 49 _+ 10 during feeding. There was a rise in carbohydrate appropriate for evaluating acute changes in nutrient oxidation rates, such as occur after feeding, and it will be of value in the factors that control such changes.
P.61
COMPARISON OF ELECTRICAL IMPEDANCE AND ANTHROPOMETRIC MEASUREMENT AND FAT AREA. Karatzas T., Brown B.H., Clark R.G. (Departments Physics, (Jniversity of Sheffield, Sheffield. U.K.)
OF UPPER ARM MUSCLE of Surgery and Medical
Methods alternative to anthropometry which measure body muscle mass and fat content such as ultrasound, C.T.scanning, neutron activation analysis and isotope dilution tend to be costly in staff and equipment and unavailable at the bedside (1‘. Ue have developed a simple, safe and inexpensive bedside technique which measures cross sectional arm muscle and fat area by electrical impedance. The method entails measuring the drop in voltage ai the mid upper arm of a lm amp current passed through the arm. The calculation of muscle and fat area is based on a resistivity of muscle of 135R cm and fat of 1600R cm and an assumed bone area of 4.5 cm2. Impedance results are compared with those derived from anthropometric measurement of skinfold thickness CSFT) and arm muscle circumference 'MAC' where arm muscle area (AMA) and fat area (AFA) are calculated as follows: MAC - II X SFT2 MAC' - AMA AMA q AFA = _p-_ 4i; 4; Reproducibility was assessed in 49 measurements in 7 patients over a period OF 6-10 days by one observer. Intra observer variation for anthropometry was 1.8 cm* AMA and 1.1 cm2 AFA and electrical impedance 1.7 cm2 AMA and 1.9 cm2 AFA. In 71 patients '48rnale and 43 female, weight range 41.2 - 125.0 Kg) the mean anthropometric AMA and AFA vlas 47.09 ? 1.1 cm2 and 15.00 2 1.0 cm2 respectively in men and 33.12 ? 0.Ycm2 nd 24.64 + 1.5 cm2 in females. Mean electrical impedance APIA and AFA were 37.72 + 0.9 cm ?! and 14.4 + 1.2 cm2 in males and 25.71 + 0.6 cm2 and 23.75 ? 1.6 cm2 in females. 0 er the whole study the range of AMA was 24.9 cm2 - 53.4 cm2 and AFA 10.4 cm2 - 46.9 cm ? . Correlation of the results of the two methods gave a coefficient r E 0.956 ~pcCJ.OOl> for AMA and I‘ = 0.9iC 'p
HAGGMARIC T., JANSSON E., SVANE B. (1778) Cross sectional by computed tomoqraphy. Stand. J. Clin. Lab. Invest. 38
127
area
of thiqh
: 355-360
mlJSC.Ie
A SENSITIVE METHOD FOR MEASURING NUTRIENT OXIDATION BY COMBINED INDIRECT CALORIMETRY AND STABLE ISOTOPIC LABELLING. P.J.Garlick, K.C.McHardy, M.A.McNurlan, A.G.Calder, J.D.Digweed, L.M.Fearns, J.Broom (The Rowett Research Institute and Aberdeen University Medical School, Aberdeen, Scotland) The nature of the substrates being oxidised by the body can, in theory, be determined if the respiratory gas exchange is measured. The calculations, however, require an independent estimate of the rate of protein oxidation. In chronic experiments it has been considered satisfactory to estimate the rate of protein oxidation from the urinary nitrogen excretion, but this is not suitable when rapid15hanges in oxidation occur, as when postabsorptive subjects are refed. We have used ( C)leucine to measure the rapid reflected by increase in amino acid oxidation on feeding, which is not nitrogen excretion. Five overnight-fasted Respiratory gases were monitored continuously oj?Sieucine oxidation were derived from the enrichment of plasma keto-isocaproate at occurred with feeding on cant731 days when no substantial rise in CO enrichment tiz the recovery of infused ( C)bicarbonate isotope was given. was found to be 72% fasted and 89% fed. Leucine was taken to be 8% of protein oxidation in both fed and fasted states and rates were calculated from data collected during the last 2 h of the fasted and fed periods. Protein oxidation rose rapidly from 33 + 6 mg/kg/h (mean _+SD) during fasting to 49 _+ 10 during feeding. There was a rise in carbohydrate appropriate for evaluating acute changes in nutrient oxidation rates, such as occur after feeding, and it will be of value in the factors that control such changes.
P.61
COMPARISON OF ELECTRICAL IMPEDANCE AND ANTHROPOMETRIC MEASUREMENT AND FAT AREA. Karatzas T., Brown B.H., Clark R.G. (Departments Physics, (Jniversity of Sheffield, Sheffield. U.K.)
OF UPPER ARM MUSCLE of Surgery and Medical
Methods alternative to anthropometry which measure body muscle mass and fat content such as ultrasound, C.T.scanning, neutron activation analysis and isotope dilution tend to be costly in staff and equipment and unavailable at the bedside (1‘. Ue have developed a simple, safe and inexpensive bedside technique which measures cross sectional arm muscle and fat area by electrical impedance. The method entails measuring the drop in voltage ai the mid upper arm of a lm amp current passed through the arm. The calculation of muscle and fat area is based on a resistivity of muscle of 135R cm and fat of 1600R cm and an assumed bone area of 4.5 cm2. Impedance results are compared with those derived from anthropometric measurement of skinfold thickness CSFT) and arm muscle circumference 'MAC' where arm muscle area (AMA) and fat area (AFA) are calculated as follows: MAC - II X SFT2 MAC' - AMA AMA q AFA = _p-_ 4i; 4; Reproducibility was assessed in 49 measurements in 7 patients over a period OF 6-10 days by one observer. Intra observer variation for anthropometry was 1.8 cm* AMA and 1.1 cm2 AFA and electrical impedance 1.7 cm2 AMA and 1.9 cm2 AFA. In 71 patients '48rnale and 43 female, weight range 41.2 - 125.0 Kg) the mean anthropometric AMA and AFA vlas 47.09 ? 1.1 cm2 and 15.00 2 1.0 cm2 respectively in men and 33.12 ? 0.Ycm2 nd 24.64 + 1.5 cm2 in females. Mean electrical impedance APIA and AFA were 37.72 + 0.9 cm ?! and 14.4 + 1.2 cm2 in males and 25.71 + 0.6 cm2 and 23.75 ? 1.6 cm2 in females. 0 er the whole study the range of AMA was 24.9 cm2 - 53.4 cm2 and AFA 10.4 cm2 - 46.9 cm ? . Correlation of the results of the two methods gave a coefficient r E 0.956 ~pcCJ.OOl> for AMA and I‘ = 0.9iC 'p
HAGGMARIC T., JANSSON E., SVANE B. (1778) Cross sectional by computed tomoqraphy. Stand. J. Clin. Lab. Invest. 38
127
area
of thiqh
: 355-360
mlJSC.Ie