250 J. LEJEUNE AND M.-O. RETHORE 



The study of the frequency of cancers and leukaemias is in i)rogress, as 

 well as the statistical screening of the 87 other physical particularities recorded. 



EEFERENCE 



Lejeune, J., TuRPiN, R., Rethore, M.-O., and Mayer, M. (1960). Rev. frmv;. Etudes 

 Clin. Biol. 5, 982. 



DISCUSSION 



mole: I would just like to ask a few questions about details. I understand that the 

 children were all ii-radiated in utero, you have the records because they were irradiated in 

 hospital, and from the hospital records you were able to deduce the dose. There are two 

 questions here. What about other kinds of radiation exposure? I'm told that in France, 

 pregnant women are fiuoroscoped under the National Health legislation, as presumably 

 happens with all the mothers; I don't know at what period in pregnancy. Secondly, you 

 have lumped all the irradiated people together under one dose. Is it possible to get any 

 kind of a dose reponse? 



lejeune: WeU, I can answer the two questions. Every cluld has a personal file and every 

 examination is recorded there as exactly as possible. The chest fluoroscopy of the mother 

 is effectively systematic but is probably not relevant in this respect. First the dose to the 

 foetus is likely to be smaU and randomly spread among the whole sample of mothers. 

 ROTBLAT: You said the average dose is 2 r. 

 LEJEUNE: Yes, of this order. 



ROTBLAT: Obviously there must be some spread. Do you know what the actual doses 

 were in the cases wliich you mentioned? 



LEJEUNE: Yes, in three cases, one had two pictures, the other had five and the other had a 

 urography — which means six. So one has received around two roentgens, and two of them 

 around five. The differences are not much greater than that. We do not have in such a 

 sample a relationship between the number of roentgens and the somatic efi"ects. 

 drasil: Have you calculated how many cells must be changed or damaged in order to 

 obtain this changed segment of the iris? 



LEJEUNE: I do not have any idea because of the possibility of a different selection value 

 for the mutant cells, but it is possible that the number is very small because a primary 

 ceU can have a big progeny. 



RUSSELL: I tliink that m this case calculation could be made in the same way as was made 

 in the case of white segments of Drosophila eyes that had been irradiated as young or 

 embryos. I'm thinking of course of just what you said, what portion this segment forms 

 of the total and suppose it forms in the average one-tenth of the total it would mean that 

 there were on the average 10 cells there. 



zeleny: Do you find any differences in the size of the segment and are they related to the 

 time of exposure? 



lejeune: Yes, we did, and it was one of the best hopes we had that the earUer the 

 irradiation the bigger should be the segment. And the only thing I can tell you is that 

 the earliest foetus — around 3 months old when it was irradiated in utero had quite a 

 large segment of one eye and that the smallest one was irradiated at 7 months, but in- 

 between the relation is linear. I am sorry, but there are variations. But then of course this 

 was expected. 



