Histological aspects of arterial abnormalities produced by X-irradiation of the aortic and branchial arches in the chick embryo.

Low dose X irradiations centred on one or two aortic and branchial arches of 3-day check embryos result in teratogenic effects on the arteries (21-92%) and in low mortality (4-12%). Histological studies of abnormal arteries show different structural malformations of the arterial wall: inorganized arterial fibres, abnormal intima, newly formed arterial tissue in arterial lumen, coalescence of two arteries. It is suggested that a disturbance at the aortic differentiation level results under our experimental conditions in the observed arterial abnormalities.