[Teratogenic effect of dicrotophos on the embryonic chick tibia ; histological and cytological studies (author's transl)].

The organophosphorus insecticide dicrotophos injected at 4 days of incubation into the yolk sac of hen'eggs determined achondroplasia with tibiotarsus deformities. These malformations were studied at different stages of embryogenesis using different histological methods. After injecting 0,5 mg per egg, the size of the hindlimbs was decreased by 50% and the growth was much less (from 20 to 30% of the normal) When giving the toxic et the level of 1 mg per egg. Light and electron microscopical observations showed a reduction or a lack of the proliferative zones and a decrease in the secretory activity of the chondrocytes which may possibly be related to the growth retardation. Using adaptated techniques for mineralized tissue examination and scanning microscope, a disorganized and an asymmetrical deposition of the periosteal osseous lamellae was observed.