A COMPARATIVE STUDY OF THE LATE EFFECTS OF 

 CERTAIN RADIOMIMETIC DRUGS AND X-RAYS 



L. N^METH 



State Oncological Institute, Budapest, Hungary 



In preliminary experiments using, first rabbits and then mice, it had been 

 established haematologically that 25 r TBR corresponded to 5 mg of Degranol 

 or 50 mg of Mannitol-myleran. 



Groups of 50 male and 50 female mice, 2 months old and weighing 15 g, 

 of a susceptible strain and of one not susceptible to spontaneous leukaemia, 

 were given for 1 year, weekly intraperitoneal injections of 5 mg/kg of 

 Degranol, 50 mg/kg of Mannitol-myleran, and physiological saline, respec- 

 tively. Another group of the same number and composition was X-irradiated 

 with 25 r. An additional 1,000 untreated and unhandled animals were ear- 

 marked for observation as controls throughout the experiment. Once a week, 

 quantitiative and qualitative white blood cell counts were taken of every 

 experimental animal, including those given saline, but only of random 

 samples from among the controls. All animals were weighed systematically, 

 initially twice and later once a week. After the third month a proportion of 

 the mice was paired. Following the 52nd week aU surviving mice were killed 

 and subjected to histology. 



KESULTS 



AU treatments raised the percentage incidence of lymphatic leukaemias 

 (stem-cell leukaemias) in the mice of the susceptible strain. The increase 

 in the rate was the lowest in the saline-treated and the highest in the 

 Degranol-treated animals (in the latter it was to 23% from the 8% seen in 

 the controls). 



All treatments increased the incidence-rate of lymph-node tumours in 

 the susceptible strain, to the greatest extent on treatment with Mannitol- 

 myleran (to 53% from 19% in the controls). Only a small proportion of these 

 tumours displayed malignancy (lymphosarcoma, reticulosarcoma, etc.). 



All treatments, particularly treatment with mannitol-myleran, shortened 

 the average life-span of the animals and impaired their resistance to infections 

 in both susceptible and non-susceptible strains. 



In addition, all treatments except that with saline produced profound 

 histological changes, namely: 



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