摘要:Because inhalation and intratracheal instillation deposit particles throughout the respiratory tract, these methods of administration give little information on the movement of particles within the lung and no direct information on the clearance kinetics from locally defined sites within alveolar tissue. Approximately 0.05 microL of 195Au-labeled gold colloid was administered to 32 rats by microinjection into a small volume of subpleural alveoli. Its fate was studied by whole-body counting and serial sacrifice over 15 months. The kinetics of clearance from the subpleural deposition site showed that there was no rapid removal of particles, and the main clearance process was defined by an exponential term with a half-time averaging 583 days. There was a wide variation between individual animals. The distribution of 195Au at sacrifice showed that the gold colloid was nearly all retained within the respiratory tract. The particles were not appreciably redistributed throughout the lung volume, so most of the material not cleared from the lung remained close to the deposition site. At the later times after microinjection, much of the gold colloid was associated with thickened pleura and adjoining septae. Full text Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (1.7M), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References . 47 48 49 50 51