CHEMICAL CHANGES IN IRRADIATED NER\ E CELLS 433 



The frozen sections were counter-stained with a variety of methods, such as 

 Oil Red "0"\ Nuclear Fast Red. or azocarmine, or were impregnated with 

 siKer carbonate, and moimted. 



Results 



Althou2,h extreme care was exercised in processing the sections, radiogenic 

 lesions were discovered and adequately demonstrated in only 5 brains. A 

 variety of factors, such as the minute size of the lesions, the tremendous 

 number of sections i over 2.500 i. and possible errors in the placing of the 

 lesions, probably accoimts for the high rate of failure. Nonetheless, the 

 material available for studv yielded interesting results. 



Animal No. 4 was subjected to 4 irradiations with 0.250 mm beams and 

 was sacrificed 5 horns later. Only the lesions produced with 120.000 and 

 240.000 rad. respectively, were found histologically. The irradiated nerve 

 cells appeared shrunken and hypcrchromatic in silver-carbonate impregna- 

 tions. No abnormal enzyme activity was noted. 



Animal No. 5 received 4 irradiations with 0.250 mm beams and was per- 

 mitted to survive 10 hours. The lesions produced with 120,000 and 240,000 

 rad. respectively, were foimd in the visual cortex. The nerve cells were 

 shrunken and hypcrchromatic. They did not show anv enzyme activity. On 

 the other hand, the vascular endothelial cells exhibited considerable activity 

 in the form of densely packed blue granules in the cytoplasm. 



Animal No. 6 received 4 irradiations with 0.250 mm beams and was sacri- 

 ficed after .31 hoius. Only the lesions in the visual cortex, produced with 

 60.000 and 240.000 rad. respectively, were foimd. The nerve cells were 

 shrunken, and a few of them contained blue granules in the cytoplasm. In the 

 dentate ligament of the Amnion's horn, the enzyme appeared to be located 

 predominantly in endothelial and proliferating microglia cells and in astro- 

 cytes. The nerve fibers of the callosal radiation were imaltered. while those 

 ot the cortical radiation exhibited retraction bulbs. 



Animal No. 8 received 8 irradiations with 0.075 mm beams and was sacri- 

 ficed after 10 hours. Only one lesion in the visual cortex, produced with 

 540,000 rad. was foimd. .\11 nerve cells in the beam path exhibited consider- 

 able enzyme activity in their cytoplasm. The nuclei were shrunken and 

 stained a deep red with azocarmine. 



Animal No. 9 received 8 irradiations with 0.075 mm beams and was killed 

 30 hours later. Six lesions were identified, produced with 180.000, 270,000, 

 and 540,000 rad. respectively. By sheer chance, in one section of the cere- 

 bellum. 3 lesions were cut on the same plane i Fig. 3 ) . In these lesions, the 

 enzvTOe activity was almost e.xclusively restricted to the Purkinje and granu- 

 lar cell lavers. In contrast, the white matter showed no activity at all, and 



