Fig. 7. (A-C) Skeletal alterations after treatments with FGFs in specimens stained with Alcian Green showing the formation of extra cartilaginous elements after implantation of FGF-beads at stage 20 in the anterior margin mesoderm (A), posterior margin mesoderm (B) and in the progress zone (C). Arrows indicate the position of the induced extra cartilaginous elements. (D-H) Changes in the pattern of cell death after treatments with FGFs in specimens vital stained with neutral red. (D-F) Control (D) and experimental wing buds showing the inhibition of apoptosis in the PNZ (E) and in the ANZ (F) 12 hours after the implantation of FGF-beads (*). (G,H) Control and experimental limbs showing the normal pattern of ANZ (G) and the increased apoptosis 24 hours after implantation of an FGF-bead (*, H) in the anterior margin mesoderm. (I) Limb bud vital stained for cell death 24 hours after implantation in the anterior margin mesoderm of an FGF-bead (*) and a Noggin-bead (arrow). Note the intense inhibition of apoptosis in the zone of influence of the Noggin-bead (compare with H).
