IRRADI.VI I().\ AM) RKPLACI-Ml-M OF lU).\i: MARROW, USING •""Au 



chromic acid and subjected to radiometric assay by y-counting with a 

 scintillation counter. Figures for specific activity of ^"^Au obtained from 

 this assay were used to estimate roentgen doses to the respective tissues. 



Biopsy sections were prepared from liver, sternum and spleen. All sections 

 were of 5 ij. thickness, routine parallin-emljeddcd and stained with hacma- 

 to.\>lin-eosin. Duplicates were prepared for detection of gold aggregates 

 by a two-hour saturation in alcoholic picric acid. Sternum specimens were 

 decalcified in 10 per cent versene. 



The total number of rabbits used was 44, grouped in five series: a, b, c, d, 

 e. The rabbits of any one scries were used simultaneously and numbered 

 with the series letter as sulTix. 



In each series a number of rabbits, referred to as controls, received doses 

 of the isotope without receiving transfusions. Those which received both are 

 referred to as 'treated'. 



Series a and b were used to determine a suitable dose level, the range of 

 specific dose for these series being 0-8 to 9-4 mC/kg. In series c, d and e, 

 a dose of 3-0 and, finally, 2-5 mC/kg was settled on. 



Series a, b, c, and d rabbits had intact spleens. Series e rabbits were 

 splenectomized eight to ten days before irradiation. 



RESULTS 



Distribution of ^^^Au 



While radiometric assays were made of liver, bone marrow and spleen 

 from each rabbit which died, occasional specimens of other organs and of 

 excreta were also assayed. In general, the uptake of ^^^Au in lung, kidney, 

 stomach, mesentery, brain, adipose tissue, the injected ear, faeces, urine and 

 whole-blood was so low that we can assume that all but an amount of the 

 order of 2 per cent of the administered dose of ^^^Au was taken up and 

 retained in liver, bone marrow and spleen. Thus, since the total uptake 

 for liver, spleen and bone marrow was about 98 per cent and that for liver 

 and spleen could be estimated from the known weights of these organs, the 

 total uptake for bone marrow was readily estimated by subtraction. 



Table 1 shows the range, mean and standard deviation for percentage 



58 



