Radiation Effects on Lymphocytes 1)5 



about 0.2 per cent of the lymphocytes were Eound to be pyknotic in blood 

 smears. It is of interest that the pyknotie cells were present only during 

 the first few hours after irradiation in the rats but were found for many 

 days in irradiated men. 



Stage of Abortive Recovery 



Blood Lymphocytes. Taylor, Witherbee, and Murphy 58 observed that 

 irradiation of a monkey, a cat, and a pony caused a minimal lymphocyte 



6000n 



5000 



4000H 



ft 3000-1 

 o 



Q. 



1 2000- 



lOOO-i 



12 RABBITS 



14 



DAYS OF IRRADIATION 



Fig. 10-10. Effects of total body irradiation with 300 r of x-rays on the number 

 of lymphocytes in the blood of rabbits. (Data from Sacher and Pearlman. 40 ) 



count in 48 hours and then a primary rise in 3 to 9 days followed by 

 a secondary fall from 5 to 12 days after the irradiation. Jacobson and asso- 

 ciates-- observed a transient rise in the lymphocyte count following the 

 initial lymphopenia in rabbits given a total body exposure of 200 r or 

 more (Fig. 10-10). The rise occurred from 4 to 1 1 days after irradiation 

 and was followed by a decline of the lymphocyte count in a few days even 

 though the animal received no additional irradiation. The temporary rise in 

 blood lymphocytes was called by Jacobson "abortive rise" or "recovery," and 

 he has reviewed its occurrence in several species.- 1 Ross, Furth, and Bigelow 

 observed an abortive rise in the number of lymphocytes in the thoracic 



