HISTOLOGICAL CHANGES AFTER IRRADIATION 1127 



With 80 r of total-body X irradiation per day to mice there is a slight 

 degree of acquired radioresistance so that nuclear debris in the crypts of 

 Lieberkiihn, although prominent during the first week, is rarely found 

 from 15 to 35 days (Pierce, 1948). No changes are observed in the 

 intestines of mice exposed daily to 8.8 r of y rays from radium when 

 examined at from two to sixteen months. 



With larger doses (2000 to 2500 r) over the abdomen of dogs much more 

 drastic changes are produced (Stafford L. Warren and Whipple, 1922). 

 Within a few days the entire epithelium of crypts and villi is destroyed 

 and sloughed off. The intestine is inflamed and hemorrhages are exten- 

 sive. There is bloody diarrhea and the animals soon die. Rats and 

 guinea pigs are slightly more sensitive than dogs, cats, or rabbits (Stafford 

 L. Warren, 1936). It has also been found that ulceration of the small 

 intestine may result after two or three weeks (Martin and Rogers, 1924). 



Internally administered radioactive isotopes affect the gastrointestinal 

 epithelium in the same way as do X rays, although some differences are 

 notable (Pierce, 1948). Radium and plutonium seem to cause more 

 nuclear swelling than the /3 and 7 emitters. With most of the parenter- 

 al^ administered isotopes there is no massive destruction of the epi- 

 thelium, as after a single 800-r dose of X rays. However, Zr 93 -Cb 93 , 

 injected intracardially, causes marked destructive lesions throughout the 

 small intestine, resulting in extensive areas of sloughed epithelium. 

 Parenterally administered Na 24 and Ba 14n -La 140 also cause severe damage 

 to the gastrointestinal mucosa, notably during the first two weeks 

 following treatment, while P 32 (2.5 /xc/g) produces moderate damage, 

 Y 91 (2.0 Mc/g) produces less, and Sr 89 (3.6 juc/g) still less. Changes in 

 the gastrointestinal tract following administration of the a emitters occur 

 at later intervals and with lower doses than with the (3 emitters. 



The effects of Y 91 , Sr 89 , and fission-products mixture, administered by 

 gavage, vary with the dose level and length of interval during which 

 the agent may act. Large doses (23 to 33 /xc/g) of fission-products mix- 

 ture cause extreme necrosis of the mucosa in rats, most marked in the 

 lower ileum and colon. Smaller single doses of fission-products mixture 

 or of Y 91 or daily doses of Y 91 as high as 2 /xc/g for three months cause 

 minimal changes. 



Salivary Glands. Damage to salivary glands has resulted from thera- 

 peutic irradiation of surrounding tissues. Functionally this is manifested 

 by a marked decrease in secretion of saliva (Bergonie and Speder, 1911; 

 Ivy et al., 1923). Histologically it has been found that the serous cells 

 are more sensitive than the mucous (although the reverse is held by 

 Lazarus-Barlow to be the case after exposure to radium) and both of 

 these more sensitive than duct epithelium (Salis, 1924). After severe 

 irradiation there is interstitial fibrosis of the organs. Desjardins, 1928, 

 reviewing the literature, states that the salivary glands are exceptionally 



