ToxSci Advance Access published online on April 15, 2003
Toxicological Sciences, doi:10.1093/toxsci/kfg075
Toxicological Sciences © Society of Toxicology 2003; all rights reserved
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Institute of Physics and Biophysics, University of Salzburg, Hellbrunner Str. 34, A-5020 Salzburg, Austria
* To whom correspondence should be addressed. E-mail: Werner.Hofmann{at}sbg.ac.at.
Mucociliary clearance velocities in human and rat bronchial airways were calculated in asymmetric, multiple-path models of the bronchial tree by solving mass transport equations based on the assumption of conservation of mucus volume and normalized to measured tracheal mucus velocities of 5.5 mm min-1 for humans and 1.9 mm min-1 for rats. Mucus velocities in single airways of the rat lung exhibited a significant statistical relationship with airway diameters but not with generation numbers, while both parameters provided equally suitable relationships for the human lung. Retention curves reflecting the combined effects of deposition and clearance were computed for unit density particles of 0.1, 1, 2, and 7µm for resting breathing conditions. About 10 to 15% of the particles initially deposited in the human bronchial tree were still retained after 24 h, while most of the particles deposited in the rat bronchial tree were cleared after about 6 to 8 h. Snapshots of the distributions of mass retained among human bronchial airways at different times after the end of exposure indicated that the observed slow bronchial clearance may partly be attributed to delayed mucociliary clearance from particles initially deposited in the most peripheral conductive airways. If plotted as functions of airway diameter, human and rat bronchial retention patterns exhibit very similar shapes, in contrast to their dependence on airway generation number. Thus extrapolation of toxicologic response, based on local retention patterns, from rat to human exposures should be based on airway diameter rather than on generation number.
© 2003 Society of Toxicology
Respiratory Toxicology
The Effect of Lung Structure on Mucociliary Clearance and Particle Retention in Human and Rat Lungs
2 CIIT Centers for Health Research, P.O. Box 12137, Research Triangle Park, NC 27709-2137, USA
Abstract 
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  J. Xi, P. W. Longest, and T. B. Martonen Effects of the laryngeal jet on nano- and microparticle transport and deposition in an approximate model of the upper tracheobronchial airways J Appl Physiol, June 1, 2008; 104(6): 1761 - 1777. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. G. Wallenborn, J. K. McGee, M. C. Schladweiler, A. D. Ledbetter, and U. P. Kodavanti Systemic Translocation of Particulate Matter-Associated Metals Following a Single Intratracheal Instillation in Rats Toxicol. Sci., July 1, 2007; 98(1): 231 - 239. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. B. Wichers, W. H. Rowan III, J. P. Nolan, A. D. Ledbetter, J. K. McGee, D. L. Costa, and W. P. Watkinson Particle Deposition in Spontaneously Hypertensive Rats Exposed via Whole-Body Inhalation: Measured and Estimated Dose Toxicol. Sci., October 1, 2006; 93(2): 400 - 410. [Abstract] [Full Text] [PDF]
|
|