Mucociliary clearance of insoluble particles from the tracheobronchial airways of the human lung

Mucociliary clearance of deposited particles in the conducting airways of the human lung was investigated using various symmetric and stochastically generated asymmetric models of the conducting tree. Mucous velocities in all airways of the conducting airways were calculated from the principle of mass balance for the mucus. These velocities were used to calculate particle residence time in all the airways of the conducting tree. Equations for the transport of particles by the mucous escalator were developed and solved numerically. The retained mass in the tracheobronchial region was calculated for a scenario of 1 h exposure followed by 2 days of post exposure. Initial deposition pattern of particles in the conducting airways was found to be crucial for the analysis of retention curves. Particles deposited in peripheral bronchiolar airways of asymmetric stochastic lungs cleared more slowly than those in more central airways. Consequently, the retention curves of the stochastic lungs with a greater number of bronchial generations exhibited longer tails than those of symmetric lungs. The results indicated that the asymmetric stochastic lung models may predict significant lung burdens even after 24 h. The extent of the difference in inter-subject variability in retained particle mass may partially explain the observation of investigators regarding greater than expected retained mass in the TB region after 24 h, without invoking any additional slow bronchial clearance mechanisms.

[1]  W. J. Bair,et al.  Plutonium inhalation studies. III. Effect of particle size and total dose on deposition, retention and translocation. , 1963, Health physics.

[2]  B. Asgharian,et al.  A multiple-path model of particle deposition in the rat lung. , 1995, Fundamental and applied toxicology : official journal of the Society of Toxicology.

[3]  D. Bohning,et al.  Bronchial deposition and clearance of aerosols. , 1973, Archives of internal medicine.

[4]  C. Garrard,et al.  Characteristics of tracheobronchial deposition and clearance in man. , 1982, The Annals of occupational hygiene.

[5]  C. Garrard,et al.  The effect of inhaled histamine on human tracheal mucus velocity and bronchial mucociliary clearance. , 1988, The American review of respiratory disease.

[6]  R. Wolff.  Effects of airborne pollutants on mucociliary clearance. , 1986, Environmental health perspectives.

[7]  D. Pavia,et al.  Radioaerosol assessment of mucociliary clearance: towards definition of a normal range. , 1986, The British journal of radiology.

[8]  G. Patrick.  The retention of uranium dioxide particles in the trachea of the rat. , 1979, International journal of radiation biology and related studies in physics, chemistry, and medicine.

[9]  J. Brain,et al.  Respiratory Defense Mechanisms , 1977 .

[10]  Icrp.  Human Respiratory Tract Model for Radiological Protection , 1994 .

[11]  Otto G. Raabe,et al.  Tracheobronchial Geometry: Human, Dog, Rat, Hamster - A Compilation of Selected Data from the Project Respiratory Tract Deposition Models , 1976 .

[12]  M. Bailey,et al.  Deposition, Retention and Dosimetry of Inhaled Radioactive Substances , 1998 .

[13]  C. Stirling,et al.  The retention of particles in large airways of the respiratory tract , 1977, Proceedings of the Royal Society of London. Series B. Biological Sciences.

[14]  A. van As,et al.  Mucus transport in the tracheobronchial tree of normal and bronchitic rats , 1972, The Journal of pathology.

[15]  Donald L. Dungworth,et al.  Inhalation toxicology : the design and interpretation of inhalation studies and their use in risk assessment , 1988 .

[16]  W. Hofmann,et al.  Monte Carlo modeling of aerosol deposition in human lungs. Part I: Simulation of particle transport in a stochastic lung structure , 1990 .

[17]  H C Yeh,et al.  Anatomic Models of the tracheobronchial and pulmonary regions of the rat , 1979, The Anatomical record.

[18]  W. Hofmann,et al.  Particle Deposition in a Multiple-Path Model of the Human Lung , 2001 .

[19]  G. Patrick,et al.  The distribution and clearance of inhaled UO2 particles on the first bifurcation and trachea of rats. , 1978, Physics in medicine and biology.

[20]  M Lippmann,et al.  Deposition, retention, and clearance of inhaled particles. , 1980, British journal of industrial medicine.

[21]  C. Gerrard,et al.  The relationships of aerosol deposition, lung size, and the rate of mucociliary clearance. , 1986, Archives of environmental health.

[22]  W. Hofmann,et al.  Biological variability influencing lung dosimetry for inhaled 222Rn and 220Rn decay products. , 1986, Health physics.

[23]  R. V. Lourenço,et al.  A, Model for Tracheobronchial Clearance of Inhaled Particles in Man and a Comparison with Data , 1979, IEEE Transactions on Biomedical Engineering.

[24]  J. Sturgess,et al.  The mucous lining of major bronchi in the rabbit lung. , 1977, The American review of respiratory disease.

[25]  Gerhard Scheuch,et al.  Measurement of lung clearance with pulses of radioactively-labelled aerosols , 1986 .

[26]  Günter Oberdörster,et al.  Lung Clearance of Inhaled Insoluble and Soluble Particles , 1988 .

[27]  Marianne Geiser,et al.  Assessment of particle retention and clearance in the intrapulmonary conducting airways of hamster lungs with the fractionator 1 , 1990, Journal of microscopy.

[28]  M Lippmann,et al.  Interspecies comparisons of particle deposition and mucociliary clearance in tracheobronchial airways. , 1984, Journal of toxicology and environmental health.

[29]  M. Lippmann,et al.  The characteristics of bronchial clearance in humans and the effects of cigarette smoking. , 1969, Archives of environmental health.

[30]  H. Yeh,et al.  Models of human lung airways and their application to inhaled particle deposition , 1980 .

[31]  G. Rudolf,et al.  Short-term and long-term clearance of particles from the upper human respiratory tract as function of particle size , 1990 .

[32]  M. R. Bailey,et al.  Measurement of the Tracheobronchial Clearance of Particles after Aerosol Bolus Inhalation , 1994 .

[33]  W. Foster,et al.  Measurement of tracheal and bronchial mucus velocities in man: relation to lung clearance. , 1980, Journal of applied physiology: respiratory, environmental and exercise physiology.

[34]  W. Hulbert,et al.  An improved method for fixation of the respiratory epithelial surface with the mucous and surfactant layers. , 1982, Laboratory investigation; a journal of technical methods and pathology.

[35]  M Lippmann,et al.  The effect of particle size on the regional deposition of inhaled aerosols in the human respiratory tract. , 1969, American Industrial Hygiene Association journal.

[36]  D. Pavia,et al.  Drug effects on mucociliary function. , 1983, European journal of respiratory diseases. Supplement.

[37]  R. G. Cuddihy,et al.  Respiratory Tract Clearance of Particles and Substances Dissociated from Particles , 1988 .

[38]  T. Hatch,et al.  Pulmonary Deposition and Retention of Inhaled Aerosols , 1964 .

[39]  L. Cruz-Orive,et al.  Histological and Stereological Analysis of Particle Retention in the Conducting Airways of Hamster Lungs , 1990 .

[40]  Albert Re,et al.  Clearance of radioactive dust from the human lung. , 1955 .

[41]  A. Wanner.  Clinical aspects of mucociliary transport. , 1977, The American review of respiratory disease.

[42]  M B Snipes,et al.  Long-term retention and clearance of particles inhaled by mammalian species. , 1989, Critical reviews in toxicology.

[43]  A. Podǵorski,et al.  Mathematical model of dust retention in the human respiratory system , 1992 .

[44]  H. Doerfel,et al.  Inhalation of U aerosols from UO2 fuel element fabrication. , 1985, Health physics.

[45]  R. Kavet,et al.  Airway macrophages. The importance of the fixation method. , 1984, The American review of respiratory disease.