LEUKAEMIA TREATED BY RADIATION 



Table •/. Survivors of W>.\ mice, injcrtrd subcutaneously (S.C.) 



or iiitra\ciiously (lA.) with 10" ceils leukaemia 151 2, treated 



after seven days with 1()2() rad X-rays and restored with normal 



isologous bone marrow 



Even in this relatively early generation it, too, was showing some acceleration 

 of growth; and at the time the mice were irradiated after 1 1 days, they were 

 clinically ill, and one had already died of leukaemia. There were no long- 

 term survivors of this experiment. 



In Experiment X, leukaemia 138/2 of the C57BL strain was used and was 

 in its third generation of passage. Out of the 20 animals fully treated with 

 X radiation and subsequent injection of bone marrow, three given 1310 rad 

 and isologous bone marrow, two given 1 125 rad and isologous bone marrow, 

 and one given 1 125 rad and homologous bone marrow lived for well over a 

 year. The doses given to C57BL mice were smaller than for CBA, as with 

 our substrains the C57BL mice are in general more radio-sensitive. 



Experiment XII was another attempt, after a couple of previous failures, 

 to treat leukaemia 151/1, then in its 24th generation. In one group the 

 radiotherapy was given after five days and in another after the standard 

 seven days. Some mice were given 1620 rad; for others, the dose was raised 

 to 1750 rad. Neither of these variations ensured a cure, and all the animals 

 died of leukaemia. 



In Experiment XIII, since leukaemia 151/1 seemed to have become more 

 malignant with the increasing number of generations, leukaemia 137/1, 

 which was in its second passage, was used. Animals were treated seven days 

 after the intravenous injection of the leukaemic cells with 1620 or 1750 rad. 

 Nevertheless, in spite of this being a recently isolated leukaemia, all the 

 treated animals died. 



Experiment XIV was similar in plan. The other newly arisen leukaemia 

 251, which was in its fifth passage, was used. Treatment was given after 

 seven days to three groups of 10 animals; the doses of X-rays were 1620, 

 1750 or 2000 rad. There was but one survivor which had received 2000 rad 

 of X-rays and, of course, was injected with isologous bone marrow. 



This record of success and failure merely points to some of the com- 

 plexities of the problem. There are a large number of variables, only some 

 of which can be controlled. 



Thus we have kept the size of the original inoculum of leukaemic cells 

 in each case to lO*'. In the early stages we did vary the route of transmission 



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