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ADVENTURES IN RADIOISOTOPE RESEARCH 



Among the numerous Jensen sarcomata obtained by grafting, there 

 were found occasionally those, which showed a spontaneous regression. 

 It seemed to be of interest to investigate if the enzyme cycle leading to 

 the formation of new desoxyribosenucleic acid molecules is undisturbed 

 in such regressive sarcomata, i. e. if the percentage renewal of the des- 

 oxyribosenucleic acid molecules present in the regressive sarcoma 

 deviates from the figure obtained in the growing sarcoma, or not. 



EXPERIMENTAL RESULTS 



In Table 1 the date of inoculation, the weight of the rat and the volume 

 of the sarcoma at different dates is given, thus demonstrating the rate 

 of regression of the sarcomata. Furthermore, the ratio of the activity 

 of 1 mgm desoxyribosenucleic acid P to that of 1 mgm inorganic P from 

 the sarcoma, the plasma and the liver respectively, is stated. 



Table 1 

 Experiraent 176: I to III 

 Male rat born ^^9 1944, inoculated with Jensen sarcoma 22/^, 



Experiment 177: I to IX. 

 Male rat born October 1944 inoculated 2-/12 



