Neil R Gibson

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Ten adult men were infused with L-[1-13C]leucine for 9 h commencing in the postabsorptive state (PA, 0-3 h), during the half-hourly feeding of low-protein meals (LP, protein = 2% calories, 3-6 h), and during feeding isoenergetic high-protein meals (HP, protein = 14% calories, 6-9 h). Leucine oxidation and turnover (protein synthesis and degradation) were(More)
1. The variability between normal individuals in the efficiency of postprandial protein utilization (PPU), a determinant of the apparent protein requirement, was examined in relation to the relative responses of protein synthesis and proteolysis to protein feeding by means of [1-13C]leucine turnover and balance studies.2. Twenty-five healthy adults were(More)
Current protein requirements for the elderly derive from 1985 FAO/WHO/UNU recommendations of no change with age in adults: i.e., 0.6 g/kg average and 0.75 g/kg safe allowance. Although concern has been expressed that protein requirements for the elderly may be greater, a review of nitrogen balance data, none of which are entirely satisfactory, indicates(More)
BACKGROUND The adequacy of indispensable amino acid supplies has received much attention in studies of protein requirements, but the availability of nitrogen for synthesis and maintenance of the supply of dispensable amino acids has been overlooked. OBJECTIVE We aimed to determine whether nitrogen balance and the endogenous supply of the dispensable amino(More)
The study was designed to evaluate the range of body composition in elite heavyweight oarswomen as well as the level of agreement between various methods used to measure this variable. Percent body fat was determined at the start of the competitive season by densitometry, taken to represent the reference standard, and measurement of total body potassium,(More)
BACKGROUND The finding that plasma glutathione turnover decreases as dietary protein intake decreases suggests that the safe amount of dietary protein, although sufficient for maintenance of nitrogen balance, may be insufficient for maintenance of cellular glutathione. OBJECTIVE Our objective was to determine the effect of the safe protein intake on the(More)
Current post-prandial studies of amino acid metabolism and utilization are consistent with a feeding mechanism mediated primarily by insulin and amino acids, with the balance between protein conservation and net deposition dependent on the amino acid supply [1-13C]leucine post-prandial kinetic tracer studies of leucine oxidation, non-oxidative disappearance(More)
The plasma concentrations of albumin, HDL apolipoprotein A1 (apoA1), retinol-binding protein (RBP), transthyretin (TTR), haptoglobulin, and fibrinogen were measured, and a stable isotope infusion protocol was used to determine the fractional and absolute synthesis rates of RBP, TTR, and fibrinogen in 12 young adults on three occasions during a reduction of(More)
To explore the nutritional significance of urea hydrolysis for human subjects, male infants being treated for severe undernutrition were given oral doses of 10 mg [15N15N]urea every 3 h for 36 h, on admission, during rapid growth and after repletion with either moderate or generous intakes of protein. Urea hydrolysis was calculated from the 15N enrichment(More)
The protein requirements of the elderly were investigated with [13C]leucine balance studies of metabolic demand, the efficiency of postprandial protein utilization (PPU) and the consequent apparent protein requirement. Ten elderly subjects aged 68-91 years (five men and five women) and ten young adult subjects aged 21-31 years (five men and five women) were(More)