M. A. GEREBTZOFF AND Z. M. BACQ^ 



{4) Liver 



In this organ, the lesions are predominantly cytoplasmic. Their intensity 

 seems to be related to the mode of fixation of the tissue. When the liver is 

 fixed in formalin, there is no difference between treated and untreated 

 mice : 6 hours after irradiation, the cytoplasm of hepatic cells shows a few 

 small vacuoles ; 4 days later, the vacuolar state is very pronounced. When 

 it is fixed in formalin and picric acid, there are marked differences between 

 treated animals and controls : in these, the vacuolar state is evident 6 hours 

 after irradiation and very pronounced 4 days later ; in cysteamine injected 

 mice, the hepatic cells seem to remain normal. 



The vacuolar state of the cytoplasm suggested lipidic degeneration. But 

 a histochemical study showed that, if some lipids were present at the begin- 

 ning of the degeneration, they disappeared later on. The lack of vacuolar 

 degeneration in cysteamine-injected animals when the liver is fixed in a liquid 

 containing picric acid may be related to the fact that this acid is an excellent 

 fixation medium for glycogen. It is possible that the linkage between gly- 

 cogen (and other polysaccharids) and proteins is fragile in the liver of 

 irradiated animals. But this fragility is greater in controls than in cysteamine- 

 treated mice : in these, picric fixation is sufficient to maintain the poly- 

 saccharids in the cytoplasm. This observation connects our study with 

 some biochemical researches, particularly those of Fischer. 



CONCLUSION 



The injection of cysteamine before irradiation eflfects a direct protection of . 

 liver and spleen. It has a strong accelerating action on regeneration in 

 spleen, intestine and probably thymus. Our observations favour the hypo- 

 thesis that protection by cysteamine is eflfective at the level of some factors 

 concerned with glycogen metabolism. 



REFERENCE 



1 Gerebtzoff, M. a. and Bacq. Z. M. Experientia, 1954, 10 341. 



291 



