Absorption and Elimination of 15N After Administration of Isotopically Labelled Yeast Protein and Yeast Protein Hydrolysate to Adult Patients with Coeliac Disease

Effect of alcohol consumption on whole-body protein turnover in healthy adults

“…We did not observe a significantly different protein supply between both study phases, either without or with red wine consumption ( Table 1). The relatively low faecal 15 N-losses, measured after both trial periods, clearly indicate the good digestibility of the 15 N-YP and were comparable with data of other studies (Table 2) [14,22,33]. The protein flux rates, defined as the total amount of protein synthesised and broken down per kilogram body weight per day, are displayed in Table 3.…”

“…Thereafter, the 15 N-YP was extracted in a slightly alkaline solution and separated from the nucleic acids by hot trichloracetic acid precipitation at pH 1.5 and 80 • C. The yeast fat was removed by washing with ethanol (96 vol%, Merck), and the remaining white wet 15 N-YP was finally air-dried at 50 • C. The 15 N-enrichment, the total nitrogen-, and the 15 N-content amounted to 88.76 at%, 13.3, and 11.84 mg/100 mg dry 15 N-YP, respectively. The complete procedure, including the composition of the yeast medium, has been described previously in detail [10][11][12][13][14].…”

Absorption and malabsorption of glycine and glycine peptides in man.

“…The advent of rapid colorimetric ninhydrin methods for plasma alpha-amino nitrogen (a-NH2N), which are nearly as specific as the gasometric determination, and of a more convenient method for specific glycine estimation, combined with recent advances in our knowledge of the physiology of absorption of protein digestion products (Crane, 1961;Matthews and Laster, 1965a), which have radically altered older views, suggested a reinvestigation of the glycine tolerance test. The object of the present work was to do this, to investigate the absorption of glycylglycine (diglycine) and glycylglycylglycine (triglycine) under similar conditions, and to apply tests of free and peptide glycine absorption in various gastrointestinal disorders.…”

On the use of tritium-labelled albumin for studies of intestinal absorption

“…In these patients most of the radioactivity was excreted in the second three-day period. Crane and Neuberger (1960) observed a similar pattern of excretion in studying the faecal elimination of 15N-labelled proteins after oral dosage in patients with intestinal malabsorption and suggested that this might represent an excretion from endogenous sources. It has long been suspected that faecal nitrogen may be largely of endogeneous origin (Voit, 1884;McCrudden and Fales, 1912) and the nitrogen balances performed on two of these patients (cases 7 and 10) on varying dietary intakes, which show that the raised faecal nitrogen was not influenced by the dietary nitrogen (Table V, Fig.…”

“…Although studies in vitro have demonstrated that the radioactive label may remain bound to protein or to protein residues during digestion Parkins, Dimitriadou, and Booth, 1960), the use of this material in vivo is unsatisfactory, for the 1311 label may become detached in the lumen of the gut (Jeejeebhoy, 1963). Apart from conventional nitrogen balance techniques, protein absorption in man can therefore only be studied using 15N-labelled proteins (Crane and Neuberger, 1960). This method provides the most physiological technique but it has the disadvantage that measurements must be made in a mass spectrometer.…”