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Respiratory Airways (respiratory + airway)

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Medical Sciences75%

Selected Abstracts

Tryptophan catabolites regulate mucosal sensitization to ovalbumin in respiratory airways

ALLERGY, Issue 3 2009
S. O. Odemuyiwa
Background:, Indoleamine 2,3 dioxygenase (IDO), the rate-limiting enzyme in tryptophan catabolism, is important in generating tolerance at the foetal,maternal interface. Studies using 1-methyl-tryptophan (1-MT), the specific inhibitor of IDO, showed that this enzyme is important in interferon-gamma (IFN-,)-dependent inhibition of allergic inflammation in the respiratory airway during immunotherapy. Aims of study:, We investigated the role of IDO in the development of allergic sensitization, leading to allergic inflammation and airway hyper-responsiveness (AHR). Methods:, We used a mouse model to generate mucosal tolerance to lipopolysaccharide-free ovalbumin (OVA) following repeated intranasal inoculation of OVA over a 3-day period. We tested the successful induction of tolerance by subsequent intraperitoneal (i.p.) sensitization followed by intranasal challenge with OVA. A slow-release pellet of 1-MT implanted into mice was used to block IDO activity prior to repeated intranasal inoculation of OVA. We measured T-cell proliferation in response to OVA, determined airway inflammation, and measured AHR to intranasal methacholine to investigate the role of IDO in sensitization to OVA. Results:, Repeated intranasal administration of OVA generated tolerance and prevented a subsequent sensitization to OVA via the i.p. route. This response was inhibited in mice receiving a slow-release pellet of 1-MT. However, we successfully reconstituted tolerance in mice receiving 1-MT following intra-peritoneal injection of a mixture of kynurenine and hydroxyanthranilic acid. Conclusion:, Our data suggest that, in addition to their role in IFN-,-mediated inhibition of allergic airway inflammation, products of tryptophan catabolism play an important role in the prevention of sensitization to potential allergens in the respiratory airway. [source]

Phase-contrast velocimetry with hyperpolarized 3He for in vitro and in vivo characterization of airflow

MAGNETIC RESONANCE IN MEDICINE, Issue 6 2006
Ludovic de Rochefort
Abstract This paper describes a technique that combines radial MRI and phase contrast (PC) to map the velocities of hyperpolarized gases (3He) in respiratory airways. The method was evaluated on well known geometries (straight and U-shaped pipes) before it was applied in vivo. Dynamic 2D maps of the three velocity components were obtained from a 10-mm slice with an in-plane spatial resolution of 1.6 mm within 1 s. Integration of the in vitro through-plane velocity over the slice matched the input flow within a relative precision of 6.4%. As expected for the given Reynolds number, a parabolic velocity profile was obtained in the straight pipe. In the U-shaped pipe the three velocity components were measured and compared to a fluid-dynamics simulation so the precision was evaluated as fine as 0.025 m s,1. The technique also demonstrated its ability to visualize vortices and localize characteristic points, such as the maximum velocity and vortex-center positions. Finally, in vivo feasibility was demonstrated in the human trachea during inhalation. Magn Reson Med, 2006. © 2006 Wiley-Liss, Inc. [source]

Tryptophan catabolites regulate mucosal sensitization to ovalbumin in respiratory airways

ALLERGY, Issue 3 2009
S. O. Odemuyiwa
Background:, Indoleamine 2,3 dioxygenase (IDO), the rate-limiting enzyme in tryptophan catabolism, is important in generating tolerance at the foetal,maternal interface. Studies using 1-methyl-tryptophan (1-MT), the specific inhibitor of IDO, showed that this enzyme is important in interferon-gamma (IFN-,)-dependent inhibition of allergic inflammation in the respiratory airway during immunotherapy. Aims of study:, We investigated the role of IDO in the development of allergic sensitization, leading to allergic inflammation and airway hyper-responsiveness (AHR). Methods:, We used a mouse model to generate mucosal tolerance to lipopolysaccharide-free ovalbumin (OVA) following repeated intranasal inoculation of OVA over a 3-day period. We tested the successful induction of tolerance by subsequent intraperitoneal (i.p.) sensitization followed by intranasal challenge with OVA. A slow-release pellet of 1-MT implanted into mice was used to block IDO activity prior to repeated intranasal inoculation of OVA. We measured T-cell proliferation in response to OVA, determined airway inflammation, and measured AHR to intranasal methacholine to investigate the role of IDO in sensitization to OVA. Results:, Repeated intranasal administration of OVA generated tolerance and prevented a subsequent sensitization to OVA via the i.p. route. This response was inhibited in mice receiving a slow-release pellet of 1-MT. However, we successfully reconstituted tolerance in mice receiving 1-MT following intra-peritoneal injection of a mixture of kynurenine and hydroxyanthranilic acid. Conclusion:, Our data suggest that, in addition to their role in IFN-,-mediated inhibition of allergic airway inflammation, products of tryptophan catabolism play an important role in the prevention of sensitization to potential allergens in the respiratory airway. [source]

Stochastic Morphometric Model of the Balb/c Mouse Lung

THE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 10 2010
Pierre Madl
Abstract The laboratory mouse is often used as a human surrogate in aerosol inhalation studies. Morphometric data on the tracheobronchial geometry of three in situ lung casts of the Balb/c mouse lung produced by the Air Pollution Health Effects Laboratory were analyzed in terms of probability density functions and correlations among the different airway parameters. The results of this statistical analysis reveal significant differences in diameters and branching angles between major and minor progeny branching off from the same parent airway at a given airway bifurcation. Number of bronchial airways generations along a given path, expressed by the termination probability, branching angles, and daughter-to-parent diameter ratios indicate that the location of an airway with defined linear airway dimensions within the lung is more appropriately identified by its diameter (or its parent diameter) than by an assigned generation number. We, therefore, recommend classifying the mouse lung airways by their diameters and not by generation numbers, consistent with our previous analysis of the rather monopodial structure of the rat lung (Koblinger et al., J Aerosol Med 1995;8:7,19; Koblinger and Hofmann, J Aerosol Med 1995;8:21,32). Because of lack of corresponding information on respiratory airways, a partly stochastic symmetric acinar airway model was attached to the tracheobronchial model, in which the number of acinar airways along a given path was randomly selected from a measured acinar volume distribution. The computed distributions of the geometric airway parameters and their correlations will be used for random pathway selection of inhaled particles in subsequent Monte Carlo deposition calculations. Anat Rec 293:1766,1786, 2010. © 2010 Wiley-Liss, Inc. [source]