[Cytophotometric determination of DNA concentration in the nuclei of the human placental trophoblast in late toxemias of pregnancy].

The distribution of trophoblast nuclei of the human placenta by their ploidy was studied in normal pregnancy and in late pregnancy toxemias by the monowave emthod of cytophotometry in visible light. In the plasmodiotrophoblast a pronounced increase in the amount of nuclei in the S-phase (up to 40%) was noted in late toxemias which suggests a considerable activation of the DNA synthesis. The placenta cytotrophoblast in late toxemias is substantially different from that in normality. The Langhans cells disappear almost completely while in normality they are present in young terminal villi till the very end of pregnancy. The amount of the island cytotrophoblasts is much greater, the distribution of nuclei according t the DNA content being of absolutely different character than in normality. A great amount of hypodiploid nuclei (up to 36%) was observed which are absent in normal conditions as well as much greater fluctuations in the amount of diploid nuclei (from 4% to 37%) as compared with the normal amount (25.9%). These data show a high amitotic activity in the island cytotrophoblast in late toxemias. The above changes in the plasmodiotrophoblast and cytotrophoblast might be considered as a compensatory reaction of the placenta to a considerably increased vacuolization and deep atrophic processes in degenerating villi.