Transplantable Chloromyeloid Leukemia in Sprague-Dawley Rats Following Injection of Actinium-227

Abstract

Chloroleukemia in the Sprague-Dawley rat presumably initiated by actinium-227 (actinium-equilibrium mixture) has been successfully transplanted in suckling rats over a period of 4 years. The morphologic and anatomic characteristics are described and found to be similar to those induced by methylcholanthrene. The successful transfer of the chloroleukemia in suckling rats was accomplished with an intraperitoneal injection of 0.1 to 0.2 ml. of leukemic whole blood without any detectable changes, after 4 years of transplantation, in either morphologic and anatomic properties or the lifespan of the leukemic animal. The chloroleukemia was also successfully transplanted in suckling rats by injection of tissue homogenates obtained from leukemic rats. The longevity of the animals injected with successful transplants appears to be a function of the number of myelocytes injected. This fact plus our inability to obtain successful transplants of the chloroleukemia with cell-free extracts leads us to conclude that leukemogenesis occurs most likely through a process of Colonization.