Figure 1.

Production of hCG in the culture medium of placental histocultures. Chorionic villi were placed on 1.5 cm² collagen sponge gels at medium-air interface into the wells of 6-well plates, 9 blocks per collagen sponge and per well. Production of hCG was measured in histoculture supernatants every 3 to 4 days from day 1 to day 18 or 21 by the chemiluminescence method. Placental histocultures were maintained in 5% CO₂ atmosphere/95% air at 37°C. Results represent mean ± SD of duplicates and are representative of 3 independent experiments.