Toxocity of inhaled 144Ce fused aluminosilicate particles in BALB/C mice. II

Three hundred twelve BALB/C mice were exposed by inhalation to aerosols of 144Ce fused aluminosilicate particles to achieve graded initial lung burdens between 0.03 μCi to 1.6 μCi 144Ce and are being observed for their life span. An additional 120 mice were exposed to 144Ce in the same form to achieve lung burdens of 0.36 +- 0.14 μCi 144Ce and were sacrificed at intervals to determine the pulmonary retention of 144Ce and to document nonlethal disease in the mice. The survival of the mice and lung tumor incidence will be compared to similar data from BALB/C mice with whole-body and thoracic gamma irradiation and C57BL/6J mice exposed to aerosols of 144CeO2. To date, with nearly 50 percent of the mice dead, there have been no significant differences in survival or tumor incidences which can be related to dose