LUNG CLEARANCE OF 4-MU-M PARTICLES COATED WITH SILVER, CARBON, OR BERYLLIUM

Lung clearance in rabbits during the 1st wk after inhalation of 4-.mu.m teflon particles tagged with Cr-51 and coated with Ag, C or Be was studied by external measurements of the radioactivity in the lungs. Ten rabbits were exposed to Ag- and C-coated particles on 2 separate occasions within 3 wk. Clearances of the 2 types of particles were quite similar. Clearance in 8 other rabbits that had inhaled Ag-coated particles was quite similar to clearance in 8 rabbits that had inhaled Be-coated particles. The result is regarded as evidence that alveolar macrophages do not play an active role in removing intact particles from the lung the 1st wk after inhalation.