CHROMOSOMES IN MURINE PRE-LEUKAEMIA 



91 



mole: Did you ever try transplanting into the region of the mediastinum? That is quite 

 an efficient place, and it presumably provides a sUghtly higher environmental temperature. 

 ilbery: No. although we had considered the possible advantage of so-caUed isotopic 

 placement we did not use the mediastinum. The inability of the pre-leukaemic cells to 

 transplant was being compared to a background of subcutaneous inoculation of estab- 

 Ushed leukaemia. 



UPTON: What proportion of primary mouse leukaemias were perfectly normal m terms of 

 chromosome number of morphology? There has been much accumulated experience 

 now, and obviously the mere fact that you don't find an abnormaUty after a good study 

 doesn't mean that aU the chromosomes, are in fact, normal. In what proportion, after an 

 adequate examination, will you fail to find these chromosomal abnormalities? 

 ilbeby: a very small proportion of thymuses in primary murine radiation-mduced 

 leukaemias in tliis stram and its cross with the T6 would apparently seem normal. I say 

 "apparently" advisedly as perhaps one cannot pick up in this system all the structural 

 changes that may be present. In our experience about 85% show chromosome change in 

 number and /or form. 



koller: What about spontaneous mouse leukaemias? 



ilbery: As regards the findings in spontaneous leukaemia, our results in the few we 

 have examined are given in Table III. Except for the Ehrlich's, the tissues were from the 

 propositi. The AK were from Metcalf at the Walter and Eliza Hall Institute in Australia, 

 the C58 from Bar Harbour and the ascites from the Royal North Shore Hospital, Sydney. 



Table III. Metaphase chromosomes from mice with spontaneous leukaemia 



Cytogenetic data 



Thymus Bone marrow Spleen Lymph gland 



Mouse Passage y^^^^ g^^_ ^^^^^ g^^^, ^j^^^ g^l^. lyj^^g g^^b. 



mode(s) (mode(s) (mode(s) (modes) 



MOLE: I don't think Prof. KoUer wiU mind my saying that he has looked at quite a number 

 of spontaneous leukaemias in AK mice which were obtained from the Chester Beatty 



