pgcs were isolated from circulating blood of stage 13 embryos ( hamburger and hamilton , 1951 ) , placed between the gr and other embryonic tissues ( neural tube , heart , allantois , liver ) as controls separated by a distance of 170 microns on collagen-coated substrate , and cultured with modified medium 199 ( kuwana and fujimoto , anat .
C0231044
pgcs
C0920502
embryonic tissues