HEMATOLOGIC EFFECTS OF RADIATION 1059 



cyte and hemoglobin values followed by a severe anemia that reached 

 its maximum at 20 days. A 75 per cent reduction in lymphocyte values 

 occurred within 3 days with a return to normal values by 35 days. A dose 

 of 10 fic/g of body weight produced a temporary lymphopenia, whereas 

 no hematologic effect was observed after single doses of less than 10 /xc/g 

 of body weight. Daily ingestion of 0.3-2.0 /xc/g of body weight of 

 yttrium produced a lymphopenia that reached a maximum at 90 days. 

 There was prompt return to normal values upon discontinuation of the 

 yttrium (Jacobson and Simmons, 1946b). 



STRONTIUM (Sr 89 ) 



Hematologic studies of the peripheral blood of rabbits, rats, and mice 

 after intraperitoneal or stomach-tube administration of strontium (Sr 89 ) 

 as a chloride in doses from 0.015-14.5 /xc/g of body weight indicated that 

 reduction in heterophil and lymphocyte values was about equal and that 

 these cells were sensitive indicators of acute and subacute effects. No 

 anemia occurred in mice following doses of 0.034 /xc/g of body weight or 

 lower, but moderate anemia was produced with a dose of 2.0 /xc/g of 

 body weight in this species. The minimal dose exerting a detectable 

 reduction in heterophil values in rats and mice was 0.22 and 0.25 /xc/g of 

 body weight. In rabbits an intraperitoneal dose of 1.0 /xc/g of body 

 weight produced a significant reduction of heterophil values, and 3.0 /xc/g 

 of body weight produced a significant reduction in hemoglobin and 

 erythrocyte values (Simmons and Jacobson, 1946). 



Of interest in connection with strontium (Sr 89 ) toxicity is the fact that, 

 in mice injected with a dose of 2.0 /xc/g of body weight, only a leukopenia 

 became apparent even though the bone marrow was markedly depleted 

 or aplastic (Jacobson, Simmons, and Block, 1949). Concomitant with 

 the development of aplasia in the marrow a myeloid metaplasia developed 

 in the spleen, which was sufficient to compensate for the lack of erythro- 

 cyte production in the marrow. In splenectomized mice a severe 

 anemia developed since compensatory blood formation in the spleen was 

 not possible (Fig. 16-15). 



RADIUM 



Hematologic studies on the peripheral blood of rats, mice, and rabbits 

 after intraperitoneal, intravenous, or intracardial injections of radium 

 chloride indicate that a macrocytic anemia develops following parenteral 

 administration of radium chloride in doses between 0.1 and 0.2 /xg. 

 Although doses below this range produced an anemia in rats and mice, no 

 anemia was produced in the rabbits with this dose. A reduction in 

 leukocyte values occurred with doses in the 0.1-/xg range in the rabbit, 

 whereas doses as high as 0.02-0.03 /xg resulted in leukocyte reductions in 

 rats and mice (Jacobson and Simmons, 1946c). 



