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SECONDARY RADIATION DISEASE FOLLOWING 



HETEROGRAFTING 



Peter Ilbery 



Radiobiology Research Unit, Department of Preventive Aledicine, 



University of Sydney 



Mice can be made to survive thirty days following lethal whole-body 

 irradiation (the conventional time taken to assess radiation recovery as 

 control irradiated untreated animals are all dead by this time), by haemo- 

 poietic grafting. However, at about six weeks post-irradiation and treat- 

 ment mice receiving haemopoietic homografts commence to suffer from 

 secondary radiation disease, the severity, extent and mortality of which 

 being dependent upon their degree of genetic disparity^. Barnes et al.^ 

 showed that secondary radiation disease could be avoided in the hitherto 

 invariably lethal chimaerical combination CBA/C57 in mice by the use of 

 spleen cells from donors less than twelve hours old. In this work an explora- 

 tory probe has been made into the possibility of using this technique for 

 across-species grafting, heterografting, notoriously unpredictable and largely 

 unsuccessful. 



Materials 



Pure strain CBA, C57 and DBA mice maintained by this unit and Wistar 

 rats, at least eight generations inbred by the McMaster Laboratory, were 

 used. The radiation source was the Theratron ^"Co Unit at the Royal 

 Prince Alfred Hospital which gave a dosage rate of 40 rad/min y-rays (1-3 

 MeV), having a 2 per cent isodose fall off from centre to edge of the 10 cm 

 diameter irradiation cage. 



Experimental 



Thirty-four DBA mice received 950 rad *'"Co lethal whole-body y 

 irradiation. An eighth generation inbred pregnant Wistar rat was the 

 source of the donor material. Ten DBA mice received 8x 10'' each of its 

 bone-marrow cells. Nine mice received 8x10*' each of foetal spleen cells 

 and five, 8 x 10** each of foetal liver cells (five and an half foetal spleens were 

 required to give this dosage ; the embryos were of greater than two weeks 

 gestation, six embryos weighing 37 -8 g). Ten irradiated control DBA mice 

 were all dead within twelve days. 



Thirty- two CBA mice received 1050 rad ^"Co lethal whole-body y 

 irradiation. A ninth inbred generation Wistar rat which had littered less 

 than fifteen hours previously was the source of donor material. Nine mice 

 received 12 x 10^ each of adult bone-marrow cells. Fourteen mice received 



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