Fate of Nickel Subsulfide during Carcinogenesis Studied by Autoradiography and X-Ray Powder Diffraction1

Sarcomas In mice were induced by i.m. and s.c. administra tion of 63Niand 36S-labeled nickel subsuifide (Ni3S2), and the fate of the Ni3S2 was studied in tumors and normal tissues during carcinogenesis. Whole-body autoradiography showed a gradual loss of solubilized 63Ni and 35S radioactivity from the site of injection. There was also a loss of nonsolubilized dust particles which appeared to be phagocytized by reticuloendothelial cells in the liver, spleen, and regional lymph nodes. Microautoradiography showed that the totally dominating ra dioactivity within both the 63Ni3S2and the Ni335S2-induced tumors was associated with dust particles. There was no spe cific or excessive localization of solubilized radioactivity in the tumors or in métastases (when present). Two patterns of lo calization of dust particles within the tumors were observed: one with particles concentrated in a central part of the tumor and one with the particles present in the periphery of the tumor. X-ray powder diffraction of the insoluble crystalline material in the tumors indicated that a conversion of the aNi3S2 to aNi7S6 and /JNiS had occurred.