Search results for "Choline"
showing 10 items of 1138 documents
Aspirin and COX-2 Inhibitor Nimesulide Potentiate Adrenergic Contractions of Human Gastroepiploic Artery
2007
Background The aim of the present study was to evaluate the intervention of COX-1- and COX-2-derived prostaglandins in the responses of human gastroepiploic artery to sympathetic stimulation and norepinephrine. Methods Rings of human gastroepiploic artery were obtained from 45 patients (26 men and 19 women) undergoing gastrectomy. The rings were suspended in organ baths for isometric recording of tension. We studied the responses to electrical field stimulation, norepinephrine, and acetylcholine, in the absence and presence of COX-1 or COX-2 inhibition. Results The COX-1 and COX-2 inhibitor aspirin at high concentrations (10 −6 to 10 −5 mol/L) and the COX-2 inhibitor nimesulide (10 −6 mol/L…
Isolation of Cholinergic Synaptic Vesicles from the Myenteric Plexus of Guinea-Pig Small Intestine
1980
The acetylcholine-rich myenteric plexus-longitudinal muscle preparation of the guinea-pig small intestine has been subjected to subcellular fractionation using modifications of both classical methods and that originally devised for bulk isolation of cholinergic synaptic vesicles from the electromotor nerve terminals of Torpedo marmorata by means of density gradient centrifugation in a zonal rotor. The latter method gave a vesicle fraction with the highest acetylcholine content so far recorded for a mammalian particulate fraction, 30.9 +/- S.E.M. 1.8 (5) nmol of acetylcholine . mg of protein-1. Electron-microscopical examination showed that it consisted of a homogeneous preparation of vesicl…
Stimulatory and inhibitory effects of ethanol on hippocampal acetylcholine release
1998
Using the microdialysis technique and sensitive HPLC procedures for the determination of acetylcholine (ACh) and ethanol, we investigated the release of ACh in rat hippocampus after acute ethanol administration. Systemic administration of ethanol (0.8 and 2.4 g/kg i.p.) led to peak ethanol concentrations of 21 and 42 mM in the hippocampus, respectively. The high dose caused a long-lasting inhibition of basal ACh release by up to 33%. Local infusion of scopolamine (1 microM) enhanced hippocampal ACh release up to eightfold in the presence of neostigmine (10 microM), and this stimulated release was also inhibited after systemic ethanol administration (by up to 45%). The low dose of ethanol (0…
Maximal degree of airway narrowing induced by methacholine and adenosine monophosphate: relationship with the decrease in forced vital capacity.
2010
Background Changes in forced vital capacity (FVC) may represent an indirect method for the detection of plateau in response to inhaled bronchoconstrictor agents. Objective To determine the relationship between the level of plateau obtained with either methacholine or adenosine monophosphate (AMP) and the decrease in FVC induced by each bronchoconstrictor agent. Methods Airway responsiveness to high concentrations of methacholine and AMP was determined in patients with intermittent asthma (n = 41) or allergic rhinitis (n = 26). Furthermore, allergen-induced changes in the response to each bronchoconstrictor agent were investigated in 18 pollen-sensitive patients. Concentration-response curve…
Efficient alkali iodide promoted 18F-fluoroethylations with 2-[18F]fluoroethyl tosylate and 1-bromo-2-[18F]fluoroethane
2003
Abstract Radiochemical 18 F-fluorination yields of several compounds using the secondary labelling precursors 2-[ 18 F]fluoroethyl tosylate ([ 18 F]FETos) and 1-bromo-2-[ 18 F]fluoroethane ([ 18 F]BFE) could be considerably enhanced by the addition of an alkali iodide. The radiochemical yield of [ 18 F]fluoroethyl choline for example could be doubled with [ 18 F]BFE and increased from 13% to ≈80% with [ 18 F]FETos. By addition of alkali iodide to the precursor, the 18 F-fluoroethylation yields of established radiopharmaceuticals, especially in the case of automated syntheses, could be significantly increased without major changes of the reaction conditions.
The Non-neuronal Cholinergic System
2001
An increasing body of knowledge indicates that the cholinergic system is not confined to the nervous system, but is practically ubiquitous. The present paper will address the question of the non-neuronal cholinergic system in vascular endothelial cells (EC). In tissue sections of human skin, immunohistochemical studies using confocal laser scanning microscopy showed ChAT (choline acetyltransferase) activity in the EC of dermal blood vessels. Positive ChAT immunoreactivity was also demonstrated in monolayer cultures of human umbilical vein EC (HUVEC) and a human angiosarcoma EC line (HAEND). That the synthesizing enzyme is not only present in EC, but also active was shown by measuring ChAT a…
Self-assembly mechanism of nanoparticles of Ni-based Prussian Blue analogues at the air/liquid interface: a synchrotron X-ray reflectivity study.
2015
Prussian Blue analogue (PBA) nanoparticles can be self-assembled at air/liquid interfaces to build novel materials with interesting magnetic features. Herein, we study the influence of the size of PBA Cs0.4 Ni[Cr(CN)6 ]0.9 and K0.25 Ni[Fe(CN)6 ]0.75 nanoparticles on the self-assembly behavior by synchrotron X-ray reflectivity. Both nanoparticles show similar Z-potential values. The phospholipid dipalmitoylphosphatidylcholine and the amino surfactant dimethyldioctadecylammonium have been used as Langmuir monolayers to anchor the PBA nanoparticles and study the interplay of forces directing the self-assembly of the nanoparticles at the surfactant/liquid interface. Whereas Cs0.4 Ni[Cr(CN)6 ]0.…
Studies on erythrocyte acetylcholinesterase in essential hypertension.
1982
There is accumulating evidence that acetylcholinesterase (AChE might be involved in the transport of sodium across biological membranes. Consequently, because in primary hypertension abnormalities in the transport of sodium by red blood cells have been documented. AChE activities were measured in hemoglobin-free red-blood-cell membranes of patients with essential hypertension. In the absence of any effectors, the Michaelis constant of AChE for acetylcholine (Km) was 1.57 . 10(-5) mol/l, both in normotensives and in hypertensives. Sodium inhibited AChE at low substrate concentrations, whereas the enzyme was activated by sodium at moderate and high substrate levels. With increasing sodium, th…
Predicting the in vivo release from a liposomal formulation by IVIVC and non-invasive positron emission tomography imaging
2010
This study aimed to predict the in vivo performance from the in vitro release of a low-molecular weight model compound, [(18)F]-2-fluoro-2-deoxy-d-glucose ([(18)F]FDG), from liposomes and by means of positron emission tomography (PET). Liposomes composed of hydrogenated phosphatidylcholine (HPC) were prepared by a freeze-thaw method. Particle size distribution was measured by dynamic light scattering (DLS). In vitro release was examined with a dispersion method detecting the radioactivity of [(18)F]FDG. In vivo release of [(18)F]FDG, following i.p. injection of the liposomes in rats, was determined by using a Micro-PET scanner. Convolution was performed to predict the in vivo profiles from …
ESR study of the liposome membrane physical parameters in the heating-cooling cycles.
1998
Abstract Changes of dynamic and structural parameters of egg yolk lecithin (EYL) liposome membranes in the heating-cooling cycles have been studied using the E S R spin probe method. The investigations were conducted in the range of temperatures from -18 °C to +60 °C. It has been found that in the range of temperatures -15 °C to +45 °C in both the heating and the cooling run the spectroscopic parameters changed practically along the same curve (reversible changes). However, after exceeding this range of temperatures one of the parameters (partition coefficient of the spin probe 2,2,6,6 -tetramethylpiperidine -1-oxyl; TEMPO) changed along a closed curve, showing the phenomenon of thermal h…