No systemic study to induce leukemia in the experimental animals with the internal irradiation with radioactive isotopes has ever been attempted. We set about experiments with this object in 1953 and succeeded in the induction of experimental leukemia in dt, ddF and ddN uniform strain mice treated with small frequent doses of P
32, Sr
89 and Ce
144.
Single dosis of the isotopes ranged from 0.03 to 0.5 μc per gram body weight twice a week was administrated to mice with the methods of intravenous injection, intraperitoneal injection, intratracheal administration and intraesophageal dripping. The total administrations of the isotopes were 7-16 times.
The development of leukemia was confirmed in higher frequencies among mice which were administered with small frequent doses of P
32. The highest incidence of leukemia throughout our experiments was about 42% in the experiment with P
32 at 0.3-0.5 μc level.
The development of leukemia remains in lower frequencies among mice which were given small frequent doses of Sr
89 or Ce
144. In the former cases we confirmed the higher incidence of osteogenic sarcoma. In the latter cases the aplasia of the bone marrow were easily resulted.
Among the Beta-emitting radioisotopes the one which has the shorter halflife and more intensive energy such as P
32 is more suitable to induce leukemia in mice so far we had experienced.
The excessive and at the same time partially abnormal regeneration preceed the development of leukemia after the administrations of small frequent doses of the radioisotopes.
The order of the intensity of the radioactivity in the bone after the administration of the radioisotope change from time to time. Such effect will also contribute to enforce the abnormal regeneration of the bone marrow.
For the development of leukemia in mice after the administration of the frequent small doses of the radioisotope we should not overlook the most intensive regenerative hematopoietic activity in the bone marrow corresponding middle portion of the long bone such as the femur.
抄録全体を表示