technique for introducing localized long lasting implants in the chick embryo

A technique is described for making chronic, localized implants of drug-impregnated Silastic in early chick embryos. This silicone material has been shown to gradually and uniformly release its impregnated contents under such conditions. Following implantation of pieces of Silastic treated with the metaphase-blocking drugs colchicine and vinblastine into the wing-buds of 4½–5 day chick embryos, 53·75% survived 4–5 days, at which time they were sacrificed. Non-impregnated (control) Silastic was also implanted in a group of embryos. In this group, 90% survived 4–5 days. The antimitotic effects of the drugs were very well localized to implanted wings, which were reduced in size by approximately 55 % at the time of sacrifice (day 8–9 of incubation). In control embryos, the implanted wings were normal in size and general morphology. It is suggested that the technique could have numerous applications for the study of neuroembryology or other aspects of embryogenesis.