A comparison of placental Thy-1 expression (PL in vivo: Thy-1) in normal (PT1, A) and abnormal placentae (PT4, D) and the extent of trophoblast differentiation (dashed lines) in early (EC) and late PT1 and PT4 trophoblast cultures (LC). Note that late culture from normal placenta shows a large syncytium aggregates (~300 μm in diameter). Abortive formation of syncytium clusters (~50 μm) is apparent in late cultures from abnormal placenta. Inserts show ERα (top) and actin bands (bottom) from western blots performed from the same cultures. [G] Quantitative evaluation of ERα expression in immunoblots shown in top inserts [A-F]. Different column superscripts indicate significant difference. Each column represents 6 measurements. Error bars = SD. Details in text.