13 results match your criteria: "Centre de Recherche Claude Delorme[Affiliation]"

A physiologically based model for denitrogenation kinetics.

Med Gas Res

January 2018

Medical R&D, Air Liquide Santé International, Centre de Recherche Claude-Delorme, Jouy-en-Josas, France.

Under normal conditions we continuously breathe 78% nitrogen (N) such that the body tissues and fluids are saturated with dissolved N. For normobaric medical gas administration at high concentrations, the N concentration must be less than that in the ambient atmosphere; therefore, nitrogen will begin to be released by the body tissues. There is a need to estimate the time needed for denitrogenation in the planning of surgical procedures.

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Argon blocks the expression of locomotor sensitization to amphetamine through antagonism at the vesicular monoamine transporter-2 and mu-opioid receptor in the nucleus accumbens.

Transl Psychiatry

July 2015

1] Département d'Anesthésiologie, Université Laval, Québec, QC, Canada [2] Faculté de Médecine, Université de Caen Basse-Normandie, Normandie-Université, Caen, France [3] Institut de Recherche Biomédicale des Armées, Toulon, France.

We investigated the effects of the noble gas argon on the expression of locomotor sensitization to amphetamine and amphetamine-induced changes in dopamine release and mu-opioid neurotransmission in the nucleus accumbens. We found (1) argon blocked the increase in carrier-mediated dopamine release induced by amphetamine in brain slices, but, in contrast, potentiated the decrease in KCl-evoked dopamine release induced by amphetamine, thereby suggesting that argon inhibited the vesicular monoamine transporter-2; (2) argon blocked the expression of locomotor and mu-opioid neurotransmission sensitization induced by repeated amphetamine administration in a short-term model of sensitization in rats; (3) argon decreased the maximal number of binding sites and increased the dissociation constant of mu-receptors in membrane preparations, thereby indicating that argon is a mu-receptor antagonist; (4) argon blocked the expression of locomotor sensitization and context-dependent locomotor activity induced by repeated administration of amphetamine in a long-term model of sensitization. Taken together, these data indicate that argon could be of potential interest for treating drug addiction and dependence.

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Argon prevents the development of locomotor sensitization to amphetamine and amphetamine-induced changes in mu opioid receptor in the nucleus accumbens.

Med Gas Res

January 2015

Département d'Anesthésiologie, Université Laval, Québec, QC Canada ; Université de Caen - Basse Normandie, Normandie-Université, Caen, France ; Institut de Recherche Biomédicale des Armées, Toulon, France.

Systemic administration of γ-amino-butyric acid type A (GABA-A) and benzodiazepine receptor agonists has been reported to block the development of locomotor sensitization to amphetamine. Here, we investigated whether the non-anesthetic noble gas argon, shown to possess agonistic properties at these receptors, may block the acquisition of amphetamine-induced locomotor sensitization and mu opioid receptor activation in the nucleus accumbens. Rats were pretreated with saline solution or amphetamine (1 mg/kg) from day 1 to day 3 and then exposed, immediately after injection of amphetamine, to medicinal air or argon at 75 vol% (with the remainder being oxygen).

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Inhalation pressure distributions for medical gas mixtures calculated in an infant airway morphology model.

Comput Methods Biomech Biomed Engin

January 2016

a Medical Gases Group, Air Liquide Santé International, Centre de Recherche Claude Delorme, 1 Chemin de la Porte des Loges, B.P. 126, Les Loges-en-Josas 78354 , France.

A numerical pressure loss model previously used for adult human airways has been modified to simulate the inhalation pressure distribution in a healthy 9-month-old infant lung morphology model. Pressure distributions are calculated for air as well as helium and xenon mixtures with oxygen to investigate the effects of gas density and viscosity variations for this age group. The results indicate that there are significant pressure losses in infant extrathoracic airways due to inertial effects leading to much higher pressures to drive nominal flows in the infant airway model than for an adult airway model.

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Background: To provide a validation dataset for aerosol deposition modeling, a clinical trial was performed in which the inhalation parameters and the inhaled aerosol were controlled or characterized.

Methods: Eleven, healthy, never-smokers, male participants completed the study. Each participant performed two inhalations of (99m)Tc-labeled aerosol from a vibrating mesh nebulizer, which differed by a single controlled parameter (aerosol particle size: "small" or "large"; inhalation: "deep" or "shallow"; carrier gas: air or a helium-oxygen mix).

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Models of the human respiratory tract developed in the past were based on measurements made on human tracheobronchial airways of healthy subjects. With the exception of a few morphometric characteristics such as the bronchial wall thickness (WT), very little has been published concerning the effects of disease on the tree structure and geometrical features. In this study, a commercial software package was used to segment the airway tree of seven healthy and six moderately persistent asthmatic patients from high resolution computed tomography images.

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Background: Inhalation of helium-oxygen (He/O2) mixtures has been explored as a means to lower the work of breathing of patients with obstructive lung disease. Non-invasive ventilation (NIV) with positive pressure support is also used for this purpose. The bench experiments presented herein were conducted in order to compare simulated patient inspiratory effort breathing He/O2 with that breathing medical air, with or without pressure support, across a range of adult, obstructive disease patterns.

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Background: The property values of therapeutic gas mixtures are important in designing devices, defining delivery parameters, and in understanding the therapeutic effects. In the medical related literature the vast majority of articles related to gas mixtures report property values only for the pure substances or estimates based on concentration weighted averages. However, if the molecular size or structures of the component gases are very different a more accurate estimate should be considered.

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Background: The bench experiments presented herein were conducted in order to investigate the influence of carrier gas, either medical air or a helium-oxygen mixture (78% He, 22% O2), on the droplet size distribution and aerosol mass delivered from a vibrating mesh nebulizer through a patient breathing circuit.

Methods: Droplet size distributions at the exit of the nebulizer T-piece and at the patient end of the breathing circuit were determined by laser diffraction. Additional experiments were performed to determine the effects on measured size distributions of gas humidity and of the droplet residence time during transport from the nebulizer to the laser diffraction measurement volume.

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The regional distribution of inhaled gas within the lung is affected in part by normal variations in airway geometry or by obstructions resulting from disease. In the present work, the effects of heterogeneous airway obstructions on the distribution of air and helium-oxygen were examined using an in vitro model, the two compartments of a dual adult test lung. Breathing helium-oxygen resulted in a consistently more uniform distribution, with the gas volume delivered to a severely obstructed compartment increased by almost 80%.

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Unlabelled: Using the rat chronic constriction injury (CCI) pain model, we evaluated whether nitrous oxide (N2O), a gas shown to have potent anti-hyperalgesic properties, may alleviate neuropathic pain. Mechanical nociceptive threshold was estimated using the paw pressure vocalization test. Thermal allodynia was challenged by measuring the struggle latency by immersion of the hind paw in a 10 degrees C water bath.

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Numerical modelling of conductive and convective heat transfers in retinal laser applications.

J Biophotonics

March 2008

Centre de recherche Claude Delorme, Air Liquide, Medical Gases, 1 chemin de la porte des Loges, 78354 Jouy-en-Josas, France.

The control of the temperature increase is an important issue in retinal laser treatments. Within the fundus of the eye heat, generated by absorption of light, is transmitted by diffusion in the retinal pigment epithelium and in the choroid and lost by convection due to the choroidal blood flow. The temperature can be spatially and temporally determined by solving the heat equation.

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A new physical model simulating the pharmacokinetics of volatile anaesthetics is presented. It consists in a ventilator connected to a water manometer. Gas is removed from the gaseous part of this manometer with a constant rate pump.

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