| pubmed-article:1236158 | pubmed:abstractText | A group of 12 beagle dogs was given weekly, individual, 10-min inhalation exposures to aerosols of 137Cs-labelled, fused aluminosilicate particles (AMAD approximately equal to 1.8 micron, sigmag approximately equal to 1.6). Whole-body counting was used to assess the pulmonary deposition associated with each exposure and the long-term retention after exposures. Groups of four dogs were removed from further exposures at the end of 10, 20 and 40 exposures, respectively. Two dogs in each group were sacrificed and the other two maintained for long-term retention measurements. The inhaled material was relatively insoluble in body fluids. In each of the sacrificed dogs, approximately equal to 96% of the body burden was in the lung and approximately equal to 1% in the tracheobronchial lymph nodes. The average pulmonary deposition was approximately equal to 20% of the inhaled aerosol for 10, 20 or 30 exposures, a value which was in agreement with previously reported single exposure data. Lower values observed for exposures 31 to 40 were apparently related to differences in respiratory patterns. The long-term, whole-body retentions appear to have effective half-lives ranging from 1200-1800 days in contrast to approximately equal to 400 days seen in singly exposed dogs. Possible reasons are discussed. | lld:pubmed |
