Search results for "Inhibition"
showing 10 items of 590 documents
Evidence of competitive inhibition for the intestinal absorption of baclofen by phenylalanine
1996
Abstract Previous studies showed that the absorption of the antispastic drug baclofen, in the rat middle intestine, is inhibited by β-alanine, γ-aminobutyric acid (GABA) and leucine. It was concluded that baclofen intestinal transport was mediated, at least in part, by the β-, γ- and α-amino acid carriers. We therefore focused our next studies on the analysis of the possible inhibition of drug absorption by an aromatic α-amino acid model compound, phenylalanine. An in situ study in the rat small intestine was undertaken in order to evaluate the effect of phenylalanine on baclofen absorption and to establish the inhibition model. Assays using isotonic perfusion solutions of 0.5 mM baclofen w…
Purification and characterization of the catabolic ?-acetolactate synthase from Leuconostoc mesenteroides subsp. cremoris
1995
The α-acetolactate synthase from Leuconostoc mesenteroides subsp. cremoris was purified to homogeneity in SDS-PAGE. The enzyme is a trimer of 3×55,000 Da. It was unstable but could be preserved by addition of pyruvate and thiamine pyrophosphate in the buffer. The enzyme exhibits Michaelis-Menten kinetics, and Km for pyruvate is 10 mM. Three intermediates in glucose metabolism (ATP, 3-phosphoglycerate, and phosphoenolpyruvate) exhibit a noncompetitive inhibition towards the enzyme. This enzyme does not require any divalent metal ion for activity. The α-acetolactate synthase from Leuconostoc mesenteroides subsp. cremoris is not inhibited by the branched-chain amino acids (valine, leucine, and…
The relation between neuronal chloride transporter activities, GABA inhibition, and neuronal activity
2020
Abstract The intracellular chloride concentration [Cl−]i in neurons is regulated by a set of transmembrane transporters, with the Cl−-loader NKCC1 and the Cl−-extruder KCC2 as most relevant members. The expression of these transporters is tightly regulated, with the general trend that KCC2 expression is low in immature neurons, which are thus characterized by a high [Cl−]i. As [Cl−]i is the main factor determining the polarity of GABAergic responses, such a high [Cl−]i is related to depolarizing GABAergic responses. However, depolarizing GABAergic responses are not per se excitatory, but can also contribute to shunting inhibition. The excitatory/inhibitory action of GABAergic responses is m…
Leukocyte migration test (LMT) in patients with thyroid disease: the response to human thyroid subcellular fractions.
1981
The response of circulating leukocytes to thyroid subcellular fractions was investigated in 19 patients with Graves' disease, 15 patients with Hashimoto's thyroiditis, 7 patients with toxic adenoma, 19 patients with nontoxic goiter and in 10 healthy students as control subjects. For this purpose, the leukocyte migration test of Soborg and Bendixen was performed against human crude thyroid extract (CTE), cell plasma membranes, nuclei, ribosomes, mitochondria and microsomes. Our results show positive LMT against: 1) CTE in patients with Graves' disease (61 +/- 13, p less than 0.001) and Hashimoto's thyroiditis (65 +/- 11, p less than 0.001) compared to controls (90 +/- 11); 2) cell plasma mem…
A computational model of postprandial adipose tissue lipid metabolism derived using human arteriovenous stable isotope tracer data
2019
Given the association of disturbances in non-esterified fatty acid (NEFA) metabolism with the development of Type 2 Diabetes and Non-Alcoholic Fatty Liver Disease, computational models of glucose-insulin dynamics have been extended to account for the interplay with NEFA. In this study, we use arteriovenous measurement across the subcutaneous adipose tissue during a mixed meal challenge test to evaluate the performance and underlying assumptions of three existing models of adipose tissue metabolism and construct a new, refined model of adipose tissue metabolism. Our model introduces new terms, explicitly accounting for the conversion of glucose to glyceraldehye-3-phosphate, the postprandial …
Evidence of a contralateral motor influence on reciprocal inhibition in man
1992
The role of contralateral movement on both H reflex and reciprocal inhibition was studied. In normal men H reflex was induced by median nerve stimulation. Reciprocal inhibition was achieved through stimulation of the antagonist radial nerve. On this basis the effects of contralateral arm movement were analized. Furthermore the putative influence of exteroceptive origin was also verified by means of digit stimulation. Results showed that contralateral arm movement did not affect H reflex amplitude; on the contrary, it was able to enhance reciprocal inhibition induced by extensors on flexors. Study of cutaneous afferents demonstrated that contralateral digit stimulation failed to elicit modif…
The influence of temporal factors on automatic priming and conscious expectancy in a simple reaction time task.
2009
In a previous study, we reported a dissociation between subjective expectancy and motor behaviour in a simple associative learning task (Perruchet, Cleeremans, & Destrebecqz, 2006). According to previous conditioning studies (Clark, Manns, & Squire, 2001), this dissociation is observed when the to-be-associated events coterminate and thus overlap in time (a training regimen called delay conditioning), but not when they are separated by a temporal delay (trace conditioning). In this latter situation indeed, there tends to be a direct relationship between subjective expectancy and behaviour. In this study, we further investigated this issue in a series of experiments where conscious …
Inhibitory control pathway to disinhibited eating: A matter of perspective?
2018
Abstract Recent studies highlight the importance of disinhibited eating and underlying inhibitory control deficits in the maintenance of obesity. So far, inhibition facets have been examined in isolation and findings are inconsistent due to different measures. This study illustrates the multifaceted nature of inhibitory control by comparing different inhibition stages in outpatients with chronic overweight (with binge eating disorder, BED, n = 24; Non-BED, n = 47) and healthy controls (HC, n = 30). Besides reporting impulsive patterns (UPPS), participants performed the Food Stroop (FST), Door Opening (DOT) and Stop Signal (SST) task with food and generic stimuli. The results showed a signif…
Secondary tactile hypoesthesia: a novel type of pain-induced somatosensory plasticity in human subjects
2004
Quantitative sensory testing revealed that pain induced by intracutaneous capsaicin injection elicited secondary hyperalgesia coexisting with secondary tactile hypoesthesia. Mapping the areas of altered mechanical sensations adjacent to the capsaicin injection disclosed that the area of secondary hyperalgesia was always nested in a larger area of secondary hypoesthesia easily detected as numbness by most subjects. Psychometric functions revealed a twofold rightward shift of tactile detection (hypoesthesia), which coexisted with a more than fourfold leftward shift of pricking pain detection (hyperalgesia) in the same skin area. As a mechanism we propose a functional switch at the spinal leve…
An assessment of prime‐boost vaccination schedules with AS03A‐adjuvanted prepandemic H5N1 vaccines: a randomized study in European adults
2012
Please cite this paper as: Gillard et al. (2012) An assessment of prime‐boost vaccination schedules with AS03A‐adjuvanted prepandemic H5N1 vaccines: a randomized study in European adults. Influenza and Other Respiratory Viruses DOI: 10.1111/j.1750‐2659.2012.00349.x. Background Long‐term persistence of immune response and safety of an H5N1 prepandemic influenza vaccine adjuvanted with AS03 (an α‐tocopherol oil‐in‐water emulsion‐based adjuvant system) was evaluated using various prime‐boost schedules that mimicked potential pandemic scenarios (NCT00430521). Methods Five hundred and twelve healthy adults aged 18–60 years received primary vaccination with one or two doses (0, 21 days schedule…