Search results for "ATS"
showing 10 items of 6881 documents
Partially competitive inhibition of intestinal baclofen absorption by beta-alanine, a nonessential dietary aminoacid.
1991
In situ intestinal absorption of baclofen in the rat in the presence of beta-alanine has been investigated. Through the perfusion of 0.50 mM baclofen solutions containing variable concentrations of the aminoacid (from 5 to 100 mM), a partially competitive inhibition of baclofen absorption was characterized: absorption rate pseudoconstants of the spasmolytic drug decrease as beta-alanine concentration increases, until a limiting value is obtained (36.8 per cent of that found for baclofen alone). A computer method was developed in order to calculate parameters governing baclofen absorption in the presence of beta-aminoacid, with the following results: Vm = 11.22 mM h-1; Km = 7.42 mM; Ki = 2.4…
Digestion and absorption rates of [3H]-oleic acid and [14C]-triolein do not differ in rats fed heated (-) and (+) gossypol cottonseed and soybean flo…
1998
This study was conducted to compare in vivo the acute effects of heated (+) and (-) gossypol cottonseed flours with those of soybean flour on lipid digestion and absorption in growing rats. Rats were fed by gastric intubation mixed [ 3 H]-oleic acid and [ 14 C]-triolein with heated flours or without flour (control). Lipid digestion and absorption were determined for 6 h after meal intubation. Both radioactivities recovered in gastrointestinal tract were significantly higher in rats fed (+) gossypol cottonseed flour than in all other groups. The majority of both recovered radioactivities was found in stomach contents, then in stomach wall and finally in intestinal wall. The distribution of b…
Kinetics of the intestinal uptake of zinc acexamate in normal and zinc-depleted rats.
1990
Abstract The uptake of zinc as acexamic acid salt in the small intestine of the anaesthetized rat was shown to be a two-phase process in normal animals. The first phase is rapid mucosal binding which satisfies the Freundlich isotherm equation and which involves about 30 per cent of the initially perfused zinc. The second phase was characterized as an apparent absorption step which obeys Michaelis-Menten and first-order combined kinetics, with the following parameters: Vm = 6.51 mg h−1; Km = 2.96 mg; ka = 0.306 h−1. In largely non-saturated conditions, an apparent global rate constant of about 2.50 h−1 was calculated. No significant interference due to endogenous zinc excretion into the smal…
Intestinal absorption pathway of gamma-aminobutyric acid in rat small intestine.
1994
Intestinal absorption of gamma-aminobutyric acid (GABA), as a model compound for gamma-aminoacids, has not been extensively studied from the kinetic viewpoint. Since data from our laboratory suggested that some competition arises between intestinal absorption of beta-alanine and GABA and since our intent was to maintain the aqueous stagnant diffusion layer in order to approach absorption tests to in vivo physiological conditions, a rat jejunum in situ study was undertaken in order to gain an insight into the mechanism of GABA absorption. In the present paper, results from assays using isotonic perfusion solutions with starting GABA concentrations ranging from 1 to 50 mM are reported. They s…
Rat proximal tubule D-glucose transport as a function of concentration, flow, and radius
1972
From earlier microperfusion studies ofD-glucose and water reabsorption in the proximal surface nephron of the rat,D-glucose was found to be removed by a saturable carrier and by an apparent coupling with net fluid reabsorption. Equations appropriate to describe this system were developed. They incorporated carrier-mediatedD-glucose transport, net water transport, and water-coupled solute transport. Water reabsorption was assumed to be constant either per unit surface area, or per unit volume of the nephron, and the rate of carrier-transportedD-glucose was assumed constant per unit length, per unit surface area, or per unit volume of the tubule. The possibility thatD-glucose could be reabsor…
Les élections professionnelles, autre visage de la société abstentionniste
2021
International audience; Les élections départementales et régionales de 2021 ont été marquées par une abstention massive que les commentateurs ont expliquée par l’absence d’enjeux clairs, les inégalités sociales ou le désintérêt des jeunes, la crise sanitaire... En revanche, on a généralement ignoré l’anomie – soit le déclin des formes de régulation et des valeurs collectives – qui frappe la société française. Les élections professionnelles en apportent une illustration. Le même phénomène abstentionniste s’y manifestait déjà avant la crise sanitaire. Une analyse détaillée en est proposée dans "Anatomie du syndicalisme" (PUG). Différents éléments sont repris dans cet article, soulignant la mo…
Políticas de acceso abierto a la ciencia en las universidades españolas
2013
El objetivo del artículo es analizar el estado de la cuestión de las políticas en favor del acceso abierto (OA) a la ciencia en las universidades españolas. Para ello se han establecido cinco grandes mecanismos de intervención (la creación de infraestructuras y prestación de servicios, la comunicación y difusión, la incentivación económica, la coordinación institucional así como la reglamentación u obligación) que permiten llevar a cabo políticas a favor del acceso abierto y que hemos utilizado para el análisis y la valoración de la situación. La recogida de datos se ha basado en un cuestionario enviado a los vice-rectores de investigación y se ha complementado con la consulta de directorio…
Il contratto collettivo aziendale in una prospettiva comparata. Italia, Francia, Spagna e Stati Uniti a confronto
2014
Sulla scorta del metodo comparato, la tesi analizza le recenti modifiche alla disciplina del contratto collettivo aziendale in Italia, Francia e Spagna, introdotte dalla legge e dagli accordi interconfederali; l'obiettivo è dimostrare un tendenziale avvicinamento degli stati europei analizzati al sistema nord-americano di relazioni industriali, in cui il rapporto di lavoro è regolato non tanto dalla legge o dall'accordo di categoria, ma dal contratto aziendale.Vengono inoltre analizzati i recenti accordi collettivi firmati alla Fiat ed alla Chrysler a partire dal processo di integrazione iniziato nel 2009. According to the comparative method, the thesis analyses the recent changes to the di…
Effects of electrical stimulation of the superior cervical ganglia on the number of ?synaptic? ribbons and the activity of melatonin-forming enzymes …
1989
Melatonin metabolism in the mammalian pineal gland is under the clear influence of sympathetic fibers originating in the superior cervical ganglia (SCG). Previous studies suggested that pineal "synaptic" ribbons (SR) as well are regulated by the gland's sympathetic innervation. To gain more insight into the mechanisms involved, we examined the effects of sympathetic stimulation on SR number and on the activity of melatonin forming enzymes, serotonin N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT). The SCG in adult male rats were stimulated electrically during daytime for either 15 or 120 min. Immediately following stimulation, the glands were removed and processed fo…
The pineal complex in Roman high avoidance and Roman low avoidance rats.
1990
Previous studies have shown that the pineal gland of Roman high avoidance (RHA/Verh) rats is larger than that of Roman low avoidance rats (RLA/Verh). In the present study measurement of enzyme activities (serotonin-N-acetyl-transferase, hydroxyindole-O-methyltransferase) revealed that pineals of RHA/Verh rats are twice as active in melatonin production than pineals of RLA/Verh rats. Indoleamine content was also higher in RHA/Verh rats, whereas noradrenaline content was the same in both lines. When values were expressed per mg protein, these differences disappeared except for N-acetyl-serotonin and noradrenaline which were higher or lower in RHA/Verh rats, respectively. Both lines had higher…