FIG. 4.

Placental anomalies in mGCMa-deficient conceptus. Transverse sections (6 μm) of Technovit-embedded placentas. At 9.5 d.p.c. (A and B), few fetal blood vessels (arrowheads) were found within the prospective labyrinth of the mutant placenta (A) compared to the wild-type placenta (B). Maternal blood sinuses (arrows) were present in normal numbers but were never close to embryonal vessels at any time during development as observed for the wild type (B and D). At 10.5 d.p.c. (C to E), fetal blood vessels (arrowheads) were present in the labyrinth of normal placentas (D) but absent from the mutant (C) and were detected only outside the placenta (E). Amorphous material (am) was frequently deposited within the labyrinth layer of mutant placentas (12.5 d.p.c. in panel F). Giant cells (gl) are indistinguishable between mutant (G) and wild type (H) at 10.5 d.p.c. and later stages of development.