Radiation Effects on Lymphocytes 137 



or clumped chromosomes. Henshaw 17 described multinucleated giant cells 

 from 4 to 72 hours after irradiation of mice with 50 r. Abnormal cells or 

 mitoses in lymphoid tissue of irradiated animals were also described by 

 Murray 3 ' and Nettleship. 39 In irradiated tissue cultures of (hick fibroblasts, 

 Lasnitzki 28 observed two transient increases in the numbers of abnormal 

 mitoses (Fig. 10-12). The maximum numbers occurred at 1 and 15 hours 

 after irradiation with 100 r. In 48 hours the cultures showed normal mitotic 

 activity and recovery. 



en 



LU 

 (/> 

 O 



cr 



00 



=> 



2 



CHICK FIBROBLASTS 



0-J-. 



T 



TiT" "TT" ~"&" ""£>"" '""56 " "~42 48 



HOURS AFTER IRRADIATION 



Fig. 10-12. Effect of irradiation with 100 r of x-rays on the number of abnormal mitoses 

 in tissue cultures of chick fibroblasts. (Data from Lasnitzki. 28 ) 



If abnormal mitoses are a criterion, irradiated human lymphoid tissues 

 undergo a stage of abortive recovery. In two individuals that died 10 and 

 24 days after accidental irradiation, the medium-sized lymphocytes in lymph 

 nodes had many abnormal mitoses with chromosomal aberrations. 10 Further- 

 more, many of the daughter lymphocytes were abnormal and many dividing- 

 cells died in mitosis. Many of the daughter lymphocytes had large hyper- 

 chromatic or multiple nuclei with the formation of some giant cells. Many 

 of the small lymphocytes had double nuclei or an unusually large amount 

 of basophilic cytoplasm. In Japanese men and women who died from 3 to 

 II days following the atomic bomb attacks, the spleen and lymph nodes 



