Urea metabolism in the digestive tract of the pig ; preliminary quantitative and qualitative data

La méthode directe d’étude des échanges de nutriments entre le sang et les contenus digestifs, déjà exposée ici (Rerat, 1977) a été appliquée à l'étude du passage de l’urée sanguine vers la lumière intestinale et de sa métabolisation en ammoniac chez le porc au cours de cinq répétitions à niveaux alimentaires différents permettant de comparer chez un même animal des régimes à 12 p. 100 de protéines contenant ou non de l’urée (3 p. 100). Il se produit une sécrétion brute permanente d urée en provenance du sang vers le tube digestif qui s’élève à près d’un gramme par heure au cours de la digestion de repas équilibrés chez des sujets en bonne santé. L’urée sécrétée n’est que partiellement dégradée (moins de 50 p. 100) en ammoniac. L’urée fournie par voie alimentaire est rapi dement absorbée (en cinq heures environ), et son addition au régime ne se traduit pas par une élévation significative des quantités d’ammoniac produites au cours de la période d’étude postprandiale (8 h) chez des animaux non adaptés à cette addition d urée.The previously reported direct method of determination of the exchanges of nutriments between blood and digestive contents (Rerat, 1977) was applied to the study of the passage of blood urea towards the intestinal lumen and its meta- bolization into ammonia in the pig. Using five replications at different feeding levels it was possible to compare in one and the same animal diets containing 12 p. 100 protein and either no urea or 3 p. 100. The amount of blood urea permanently secreted in the gut during digestion of a balanced meal in healthy animals ranged around 1 gramme per hour. The urea secreted was only partially degraded ( less than 50 p. 100) into ammonia. Dietary urea was rapidly absorbed (within about 5 hours) and its addition to the diet did not lead to a significant elevation in the amounts of ammonia produced during the postprandial period (8 h) in animals non adapted to this addition of urea

Quotient Categories and Phases

We study properties of a category after quotienting out a suitable chosen group of isomorphisms on each object. Coproducts in the original category are described in its quotient by our new weaker notion of a 'phased coproduct'. We examine these and show that any suitable category with them arises as such a quotient of a category with coproducts. Motivation comes from projective geometry, and also quantum theory where they describe superpositions in the category of Hilbert spaces and continuous linear maps up to global phase. The quotients we consider also generalise those induced by categorical isotropy in the sense of Funk et al.Comment: Fixed typos, added discussion of isotropy, expanded introductio

Analysis of new biodegradable amphiphilic water-soluble copolymers with various hydrophobe content by multi-angle light scattering on line with flow field flow fractionation

Flow field flow fractionation (F4) with an on-line multi-angle laser light scattering detector was used to characterize amphiphilic biodegradable water-soluble copolymers poly(methyl glyoxylate -co- potassium glyoxylate). These new products are prepared from hydrophobic poly(methyl glyoxylate) by partial and statistical saponification of methyl ester functions. Conformational shape and degradability of polymers in dilute aqueous solution were investigated as a function of saponification rate (y) ranged from 10 to 100%. Derivatives with high hydrophobe content (y=10%) forms compact intermolecular aggregates. In contrast, macromolecules of poly(potassium glyoxylate) (y = 100%) are molecularly dispersed in solution because of the presence of numerous electrostatic repulsions. For intermediate compounds(15 less than or equal to y less than or equal to 81%), the major part of the sample is represented by a population of single polymer molecules dispersed in solution. The kinetics of degradation of these different copolymers in aqueous solution was found to be a direct function of the macromolecular conformation and the percentage of methyl ester groups on the polymer chains

Absorption intestinale en présence de glucides, des acides aminés provenant de solutions de petits peptides ou d'acides aminés libres infusées dans le duodénum chez le porc éveillé

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Absorption intestinale et métabolisme hépatique, chez le porc éveillé, soumis à perfusion duodénale d'une solution glucidique contenant un hydrolysat ménagé de protéines laitières ou un mélange d'acides aminés libres de même composition. I. Glucose et azote aminé

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Progesterone freeze-dried systems in sublingual dosage form

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