Effect of $sup 144$Ce inhaled in fused-clay particles on the tracheobronchial lymph nodes
Tracheobronchial lymph node changes and lymphopenia are sequelae of inhalation of relatively insoluble radioactive aerosols by beagle dogs. The tracheobronchial lymph nodes from dogs that inhaled $sup 144$Ce in fused-clay particles were examined at intervals from 2 to 730 days after exposure to assess the development of these lesions. Initial lung burdens in the dogs studied ranged from 33 to 63 $mu$Ci/kg of body weight. The concentration of radioisotope in the tracheobronchial lymph nodes increased during the first year after exposure and exceeded that in the lung about 100 days after exposure. Autoradiographs of the lymph nodes showed that $sup 144$Ce particles were present in macrophages in the paracortical zone two days after exposure and that concentrations continued to increase in the paracortical zone and medullary cords. Histologic changes in the nodes included atrophy of the germinal centers and lymphocytic follicles, loss of lymphocytes and accumulation of macrophages in the paracortical zone, accumulation of pigment and isotope-laden macrophages in the medullary cords, occasional infiltrates of neutrophils in the medullary cords, and at later time periods focal fibrosis of the medullary cords. Tracheobronchial lymph node weights of the dogs exposed to $sup 144$Ce in fused clay were not decreased until 512 days after exposure. These findings indicate that tracheobronchial lymph nodes accumulate relatively high burdens of $sup 144$Ce after $sup 144$Ce is inhaled in a relatively insoluble form and that the pathologic changes resulting from these burdens are basically atrophy of the nodes. Primary neoplasms in lymph nodes were not observed in dogs with initial lung burdens of 0.0024 to more than 30 $mu$Ci/kg of body weight followed for up to 2000 days after exposure. At the higher levels, however, a high incidence of primary pulmonary neoplasia was observed. (auth)
- Research Organization:
- Lovelace Foundation for Medical Education and Research, Albuquerque, NM; Battelle Pacific Northwest Labs., Richland, Wash. (USA); USAEC Division of Biomedical and Environmental Research, Washington, D.C.
- NSA Number:
- NSA-33-023567
- OSTI ID:
- 4052535
- Report Number(s):
- CONF-740930--
- Country of Publication:
- United States
- Language:
- English
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