Growth of the chick area vasculosa in ovo and in shell-less culture.

The rates of growth and cell proliferation of the chick area vasculosa (Days 2-5 of incubation) were examined in windowed eggs and in shell-less culture preparations. For embryos of developmental Stages 15 to 23, the area vasculosa in shell-less cultures was significantly smaller than in corresponding eggs; however there was no significant difference in the radial growth between these groups. The cultivation of embryos in shell-less culture did not affect the normal macroscopic or histological appearance of the membrane, or the rate of proliferation of its constituent cells, as assessed by tritiated thymidine incorporation. These results indicate that the area vasculosa in shell-less culture provides a suitable assay of factors which regulate angiogenesis.