504 BIOLOGICAL EFFECTS OF RADIATION 



KIDNEY 



There is considerable controversy over changes which might occur in 

 the kidney following irradiation. In general, the experimental results 

 with animals indicate that there is no definite kidney damage to be noted 

 histologically following doses of the order of human epilation doses in 

 the animals (reviewed by Warren, 381; and Desjardins, 72, 74). What 

 changes are found after such dosage are usually functional and transient 

 (147, 224). Experimental animals, especially dogs, often show spontane- 

 ous changes in the kidney which might mask incipient changes due to 

 radiation (111). Other workers (136, 137, 255, 256, 388, 389, 404) 

 have studied changes produced in the kidney by irradiation after trans- 

 plantation or some other method of delivery of the kidney directly into 

 the field of irradiation. These experiments allow of a great increase 

 in dosage to the kidney without the probability of damage to nearby 

 structures, especially the intestines, as well as the skin, for if the kidney 

 is left in situ, very large doses, depending upon the size of the animal 

 (3000 to 5000 r or more), are necessary to damage its substance. Large 

 doses cause acute and chronic changes of various degrees with destruction 

 of blood vessels, glomeruli, and tubules, with generalized sclerosis of the 

 kidney, a condition which gradually results in secondary changes such as 

 hypertension and cardiac hypertrophy and functional disturbances such 

 as acidosis, nitrogen retention, polyuria, edema, and all the changes 

 secondary to such dysfunction which might be expected to accompany the 

 histological picture of extensive damage and resultant fibrosis. 



Alterations in the vessel walls in the kidney are found resembling in 

 all gradations those in the capillaries of the skin (111). The vessels may 

 become sclerotic and thickened and even closed. In the glomeruli they 

 are often hyalinized and atrophic, though occasional vessels seem to 

 escape damage. 



Swelling of the renal epithelium, particularly in the tubules, and 

 occasionally hemorrhage into the interstitial tissues, occur immediately 

 after the irradiation (80). Separation from the basement membrane is 

 then noted, and later cell destruction or atrophy occurs (with casts in the 

 urine). There is finally complete necrosis of the tubules, followed by 

 inflammatory cell infiltration and fibrosis and later shrinkage of the kid- 

 ney. In this stage the glomeruli may be surrounded by scar tissue and 

 very well preserved, but the tubules do not regenerate (388, 389) and 

 are replaced by scar tissue (136, 137). Radioactive materials (thorium 

 X) placed in the kidney substance produce local damage to all nearby 

 structures because of the high dosage (246). 



In general, the kidney as a whole is probably as resistant as the blood 

 vessels in the kidney or elsewhere in the body. Specific damage to 

 renal epithelium is of the same dosage level as that to blood vessels. It 

 is hardly likely that sufficient radiation may reach the kidney in situ 



