[Study on tissue culture of human chorionic tissue from early gestation: identification and observation of human trophoblast grown by a new culture method (author's transl)].

Fixed gelatin film was devised as culture matrix to establish a culture method by which the behavior of human trophoblast can be directly observed from early culture time for its cell-biological investigation. Through cultures of 90 immature placentas, it has proved to be an excellent matrix in regard to sureness, rapidity and predominance of the growth of cytotrophoblast. The grown cells were identified by light and electron microscopy of vertical sections, which histologically demonstrated that dominantly grown cells had originated from Langhans' cells and multinucleated giant cells from the syncytiotrophoblast or fused Langhans' cells. The observations of the cytotrophoblast from early culture time revealed great variety of its shape and size, and behaviors suggestive of its tumor cell-like properties; active migration and criss-cross overlapping. On the surface of the cytotrophoblast, very characteristic circular lamellar structure was observed. It was considered to be a representation of endocytotic function of the cytotrophoblast or its rapid and effective response mechanism to environmental changes. The multinucleated giant cells from fused Langhans' cells could be expected as an in vitro model of syncytiotrophoblast, which is, in vitro, susceptible to degenerative changes. Immunofluorescent staining for hCG and histochemistry for alkaline and acid phosphatases were also performed.