AUGMENTATION DE LA SYNTHESE DE l'hEMOGLOBINE Ul VltVO 



Figure 1 shows the result of such an experiment. Here a dose of 1,000 r was 

 given in 3 mins. and the culture continued for 17 hours. The only change observed 

 is that of a marked shift in the differential count of the normoblasts. There are 

 72 per cent early normoblasts (E.N. — pro, baso, and early polychromatic normoblasts) 

 and 28 per cent late normoblasts (L.N. — late polychromatic and orthochromatic 

 normoblasts) in the control culture while the irradiated specimen contained only 

 10 per cent E.N. but had 90 per cent L.N. The upper average grain count and the 

 per cent positivity did not alter appreciably. These changes were not considered 

 significant in any of the 12 marrows examined with doses varying from 300-5,000 r. 



100- 



90- 



80 



70 



\ 60 



I 50 



t 

 •^ H-0 



30 



20 



10 



EN 





m 



LN 



■■2M:-:10y. 



LN 



FN 



y-30-: 



■■'■10 



Control 



Figure 1 



Irradiated 



These data have suggested to us that those cells which had not received damage 

 due to the in vitro radiation which was lethal by the time we observed them, had 

 been able to take up iron at an essentially normal rate. We did not evaluate changes 

 in reticulocytes properly and therefore cannot comment on them. However, we 

 found nothing to indicate that iron uptake in vitro by human normoblasts was either 

 accelerated or depressed by the rather large doses of radiation used. It seems, 

 therefore, that the observed depression of marrow turnover rate in vivo following 

 total body radiation may result from a mitotic inhibition or delayed maturation or 

 some other factor than an interference with the actual uptake of iron. 



200 



