[Teratogenic effects of localized x-irradiation of branchial and aortic arches of chick embryos (author's transl)].

X-irradiation of branchial and aortic arches of 3 day old chick embryos is lethal in only a small number of cases (3-12,5%), but results in a high proportion (30-96%) of arterial malformations. The production of arterial anomalies is not random, but is related to the experimental method used and the function of the aortic arch with respect to the dynamics of circulation. Numerical and statistical studes, together with histological examination of the irradiated branchial and aortic arches, have revealed the importance of: the immediate environment of the aortic arch on its morphogenesis, the moment at which the teratogenic aggression occurs and the role of haemodynamics in the fate of the aortic arches. To explain aortic teratogenesis, we propose a hypothesis according to which all arterial anomalies are of morphogenetic origin. These anomalies can result in circulatory modifications which, in turn, cause new malformations.