| Autor: |
FOSTER, W. M., LANGENBACK, E. G., BERGOFSKY, E. H. |
| Zdroj: |
Annals of Occupational Hygiene; 06/01/1982, Vol. 26 Issue 2, p227-244, 18p |
| Abstrakt: |
Mucociliary function at various generations of the tracheo-bronchial tree was studied in man after inhalation and deposition of radioactive particles by gamma camera imaging. Quantitative values for linear velocities of mucus movement in trachea and large bronchi could be compared with the clearance rates from the whole lung. Mucus transport velocity in normal subjects averaged 5.5 mm min for the trachea and 2.4 mm min for main bronchi, and these velocities were associated with average lung clearance rates of 0.51% min for particles deposited on the ciliated airways. Only two of six bronchial asthma patients had measurable large airway velocities; the remainder exhibited mucus stasis in hilar regions with failure of transport through major bronchi and trachea, which correlated with lung clearance of only 0.26% min. Beta-adrenergic aerosols enhanced mucociliary function in the normal subjects by increasing both central airway mucus transport (bronchial and tracheal velocities were raised 156 and 37% respectively) and lung clearance (by at least 50%). In the patients, beta-adrenergic aerosol increased mucus transport velocities to 2.5 and 3.7 mm min for the main bronchi and trachea, respectively, and lung clearance rate to 140% over control rate. The marked delay in mucus transport in bronchial asthma occurred despite central particle deposition, almost wholly on the ciliated airway, which should have produced rapid lung clearance of particles. These data indicate that the ratio of tracheal to bronchial mucus transport velocities is equal to 2.7 in the normal lung; that tracheal velocities are normally close to maximum stimulated by beta-adrenergic agonists; that large bronchi have velocities only 40% of maximum. Bronchial asthma patients combine depression of mucus transport in peripheral, bronchial and tracheal airways, and all transport values are susceptible to marked increases with beta-adrenergic agent. [ABSTRACT FROM PUBLISHER] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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