DISCUSSION 

 CONCLUSIONS ET RESUME 



(1) La synthese de riiemoglobine in vitro par les reticulocytes de chien 

 irradie est augmentee par rapport au sang preleve avant I'irradiation de 

 ranimal. 



{2) La synthese de rhemoglobine est egalement augmentee dans les 

 reticulocytes normaux mis en presence de plasma d'animal irradie. 



{3) Cette meme synthese est acceleree dans le sang irradie in vitro. 



(4) Le plasma irradie seul, in vitro, jouit egalement de proprietes stimula- 

 trices de la synthese. 



(5) L'intervention d"un facteur humoral accelerant la synthese de 

 rhemoglobine apres irradiation est de la sorte demontree. 



REFERENCES 



1 Anson, M. L. et Mirsky, A. E. J. Gen. Physiol. 1930, 13 469. 



2 Back, A. et Bloch-Frankenthal, L. Proc. Sac. Exper. Biol. a. Med. 1947, 66 366. 



3 Borsook, H., Deasy, C. L., Haagen-Smit, A. S., Keighley, G. et Lowy, P. H. 

 J. Biol. Chem. 1952, 196 669. 



* Chanutin, a. et Ludewig, G. Amer. J. Physiol. 1951, 166 381. 



5 Forssberg, a. et Hevesy, G. Arkiv for Kemi, 1952, 5 93. 



6 Lambert, S. Arch. Intern. Physiol. 1953, 61 462. 



■^ London, L M., Shemin, D., West, R. et Rittenberg, D. J. Biol. Chem. 1948, 173 

 797 ; 1949, 179 463 ; 1950, 183 749. 



* Ludewtg, S. et Chanutin, A. Amer. J. Physiol. 1951, 166 384. 



^ Lybeck, H., Lambert, S., Nizet, A. et Bar.\c, G. Arch. Intern. Physiol. 1954. 62 



304. 

 i« Muir, H. M. et Neuberger, A. Biochem. J. 1949, 45 163 ; 1950, 47 97. 

 " Nencki, M. et Z.\LESKi, J. Z- Physiol. Chem. 1900, 30 384. 



12 Nizet, A. Recherches sur la Nutrition et la Regeneration des Hematies, Liege, 

 Vaillant-Carmanne, 1951. 



13 Nizet, A. Rev. Med. Liige, 1953, 8 506. 



1* Nizet, A., Bacq, Z. M. et Herve, A. Arch. Intern. Physiol. 1952, 60 449. 



15 Nizet, A. et Lambert, S. ibid, 1953, 61 120. 



16 Nizet, A. et Lambert, S. Bull. Soc. Fr. Chim. Biol. 1953, 35 771. 

 1^ Nizet, A. et Lambert, S. ibid, 1954, 36 307. 



18 Nizet, A. et Robscheit-Robbins, F. S. Blood, 1950, 5 648. 



13 Richmond, J. E., Altman, K. L et Salomon, K. J. Biol. Chem. 1951, 190 817. 



DISCUSSION 



H. Suit : I would like to mention in connection with Nizet's report and the well- 

 known depression of the marrow iron turnover rate following low dose (25 r) total 

 body radiation in the rat, that we have examined the effect of 300-5,000 r in vitro 

 on the ability of normoblasts of human bone marrow in culture to take up iron. 



For the culture of the human bone marrow we used the technique of Lajtha of 

 our laboratory. Irradiation was given at the beginning of the culture period (0 hr.). 

 ^®Fe-globulin was added at the third hour of culture in the amount of 1 jjLc/ml culture 

 medium. After 17-20 hours the culture was opened and autoradiographs prepared, 

 which were developed and stained after a period of 4 weeks' exposure. This per- 

 mitted a differential count on the erythroid series, a count of grains over individual 

 cells, and the determination of the percentage of the cells of any group that showed a 

 positive autoradiograph. 



199 



