PROGRESS OF THE ISOTOPIC METHODOLOGY 



loo: 



was higher than to be expected in view of the comparatively high plasma 

 iron figures. This result strongly suggests the explanation that the life- 

 cycle of the red corpuscles of these patients was shorter than normal. 

 That the life-span of the red corpuscles of these patients was markedly 

 shortened could be shown by Dal Santo by labelling these with ^iCr 

 in vitro, reinjecting the labelled erythrocytes and following the rate 

 of loss of their ^^Cr content. The label was lost more rapidly by the red 

 corpuscles of most patients investigated than by the red corpuscles of 

 normals, as seen in Fig. 8, indicating a shorter life-cycle of the red cor- 

 puscles of the cancer patients. A similar observation was made in other 



k?- 



60 80 100 120 140 

 /4q iron In 100 ml. plasmo 



160 180 2C0 



Fig. 7. T Y2 of the extrusion rate of labelled iron atoms from 

 the plasma plotted against the plasma iron level. 



investigations as well. A shortened life-span of erythrocytes in leukemia 

 patients was in several cases observed by Berlin and his associates'^. 

 Miller et al.ii investigated patients with leukemia and malignant lym- 

 phoma and found 2/3 of these to show an increased red cell destruction. 

 In 15 out of 19 patients in a progressive cancerous state Hyman and 

 Harvey(i6) found a shortened life- cycle of the erythrocytes. 



In many cases the shortened life-cycle of the red corpuscles does not 

 lead to a corresponding anaemia, as it is partly or wholly compensated 

 by an increased formation rate of red corpuscles. This fact is con- 

 spicuously demonstrated by the results of animal experiments. In our 

 laboratory G. v. Ehrenstein injected several hundred mice with 

 glycine-i4C-2 and compared the effect of inoculation of ascites cancer 

 cells 5 days later on the life-span of red corpuscles which were formed, 

 thus labelled, in a non-cancerous milieu. Groups of mice were killed at 



