Control and Modification of Methods for Determination of 15N in Biological Material.

Fürst, Peter; Jonsson, Anita

doi:10.3891/acta.chem.scand.25-0930

Cited by 15 publications

(3 citation statements)

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“…In the present study L-lysine was used because of its availability, its high free concentration in plasma and thus the relatively small volume of plasma (15 ml) required for I5N analysis of free lysine, and its relatively high percentage contribution to the total nitrogen of mixed muscle proteins (Furst & Jonsson, 1971). Muscle biopsies were obtained at 14 and 30 h, when plasma concentrations of [15N]lysine had reached a plateau.…”

Section: Discussionmentioning

confidence: 99%

Measurement of Muscle Protein Synthetic Rate from Serial Muscle Biopsies and Total Body Protein Turnover in Man by Continuous Intravenous Infusion of l-[α-15N]lysine

Halliday¹,

McKeran²

1975

Clinical Science

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1. Five healthy male subjects were studied by continuous infusion of L-[alpha-15N]lysine over 20-30 h with timed blood and urine samples, and two or three percutaneous needle biopsies of vastus lateralis muscle. 2. A standard creatine-free diet, quantitatively related to body surface area, was given for 5 days before the infusion. The [15N]lysine was administered at a constant rate in an amino acid solution with a nitrogen content of 0-96 mol/l, which constituted the sole source of exogenous nitrogen during the infusion. 3. A plateau level of plasma free [15N]lysine enrichment was achieved after infusion for 14 h. The total plasma lysine flux calculated from the plateau was 7-3 mmol/h (range 4-8-9-6). Total body protein turnover calculated from the lysine flux was 3-5 g day-1 kg body wt.-1 (range 2-5-5-0). 4. Muscle sarcoplasmic and myofibrillar fractions were separated, purified and the 15N enrichment was measured. The sarcoplasmic protein fractional synthetic rate was calculated as 3-8%/day (range 2-2-5-1). The myofibrillar protein synthetic rate was 1-46%/day (range 1-09-2-44). 5. Muscle mass, calculated from 24 h creatinine excretion, was 33-7 kg (range 28-8-37-4), which represented 50-0% of body weight (range 38-9-58-1). Total muscle protein synthesis was calculated to account for 53-2% (range 39-5-62-1) of total body protein syntehsis. 6. The advantages and limitations of using continuous infusion of [15N]lysine in human subjects are discussed.

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Section: Discussionmentioning

confidence: 99%

Measurement of Muscle Protein Synthetic Rate from Serial Muscle Biopsies and Total Body Protein Turnover in Man by Continuous Intravenous Infusion of l-[α-15N]lysine

Halliday¹,

McKeran²

1975

Clinical Science

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“…A liver sample was homogenized in physiological saline (8.5 g sodium chloride/L). The homogenized liver sample, and samples of the contents of the small intestine, cecum, colon and serum were treated with one‐fifth of their volume of trichloroacetic acid (TCA) solution (500 g/L), centrifuged (12 000 × g for 20 min at 4°C) and washed twice with TCA solution (50 g/L) (Fürst & Jonsson ). The TCA precipitates were analyzed for total N and protein N using a CN analyzer (Yanaco CN Corder, MT‐700, J‐Science, Kyoto, Japan).…”

Section: Methodsmentioning

confidence: 99%

Transfer of blood urea nitrogen to cecal microbes and nitrogen retention in mature rabbits are increased by dietary fructooligosaccharides

Xiao

Kawasaki

et al. 2014

Animal Science Journal

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To estimate the effect of fructooligosaccharides (FOS) on N utilization, seven mature rabbits were fed a diet containing 5% glucose or FOS for 8 days. During the last 5 days, total feces and urine were collected to measure N levels (Experiment 1). To examine N transfer from the blood to cecal microbes, eight rabbits were fed the same diets as in Experiment 1. After 9 days of feeding, 2 g of glucose or FOS was given orally. Two hours later 20 mg of (15) N-urea was administered via the ear vein, and 1 h later cecal and blood samples were collected (Experiment 2). Urinary N excretion was lowered by FOS feeding (P < 0.05). Total bacterial N and (15) N in the cecum was significantly higher in FOS-fed animals (P < 0.05). Urea N in the cecum was lower in FOS-fed rabbits (P < 0.05). Similarly, (15) N atom % excess of cecal urea N was also lower in FOS-fed rabbits than in glucose-fed rabbits. These results suggest that FOS in the diet increases the transfer of blood urea N to the cecum for bacterial synthesis, thereby increasing N utilization.

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“…8 The same general technique of adminis-tering a labeled compound and determining the stable isotope abundance in an isolated product is, with refinements, still in use today. 3 In more recent development of the technique, isotope mixtures are administered and the artificially created mass spectral isotope cluster is used as a qualitative label. Such isotopes may also be useful as internal standards for quantitative measurements with mass spectrometry or gas chromatography-mass spectrometry.…”

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confidence: 99%

Use of stable isotopes in pharmacology‐clinical pharmacology

Knapp

Gaffney

1972

Clin Pharma and Therapeutics

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The greatest advantages offered by stable isotopes over their radioactive counterparts is the absence of problems associated with radiation. Absence of possible radiation damage to living systems is very important in human studies, especially in the case of children or pregnant women. Absence of radiation hazard also makes the synthesis and handling of stable isotope‐labeled compounds much simpler.

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Control and Modification of Methods for Determination of 15N in Biological Material.

Cited by 15 publications

References 0 publications

Measurement of Muscle Protein Synthetic Rate from Serial Muscle Biopsies and Total Body Protein Turnover in Man by Continuous Intravenous Infusion of l-[α-15N]lysine

Measurement of Muscle Protein Synthetic Rate from Serial Muscle Biopsies and Total Body Protein Turnover in Man by Continuous Intravenous Infusion of l-[α-15N]lysine

Transfer of blood urea nitrogen to cecal microbes and nitrogen retention in mature rabbits are increased by dietary fructooligosaccharides

Use of stable isotopes in pharmacology‐clinical pharmacology

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