EFFECTS OF HEAVY HIGH ENERGY CHARGED PARTICLES. IV. THE FATE OF GIANT CELLS PRODUCED IN A NEOPLASM BY 20-Mev DEUTERON BOMBARDMENT

Experiments were designed to bombard transplantable mouse Sarcoma 37 with a beam of 20-Mev deuterons from the Brookhaven 60-in. cyclotron. In the first studies, 1-mm cube of tumor was irradiated in vitro and immediately transplanted so that if giant cells developed they could be recognized clearly as not having arisen from the host, and their subsequent capacity to reproduce could be determined. In the second study, tumor was transplanted before being irradiated in vivo. In both experiments giant tumor cells developed as a result of bombardment with deuterons, and their microscopic appearance and biological behavior were studied. In both experiments certain changes common to each were noted. At the lowest dose (400 rad) no giant tumor cells were found. At the other extreme, exposures of 10,000 and 50,000 rad proved to be very rapidly cytocidal to the neoplastic cells. Profound alterations occurred in the neoplastic tissue at doses of 2500 to 3000 rad with formation of giant cells and death of most of the neoplastic cells by 72 to 96 hr. By then most of the residualtumor cells were enlarged up to about 10 times normal size; nuclei increased in size and chromatic content, with prominent nucleoli. By the 7thmore » to 10th days after irradiation, giant neoplastic cells were no longer found and all traces of neoplastic cells had disappeared, whereas in the nonirradiated transplanted neoplasms at these periods growth was profuse. (BBB)« less