[Proliferative zones of the epithelium of human embryonic brain choroid plexuses].

The study performed in 7-13 wks old human embryos by using immunocytochemical detection of PCNA, the proliferation marker, has demonstrated that in choroid plexus of telencephalon proliferative zone is located in the area of the base of the plexus--at the border with the ventricular zone of brain cortex anlage and in choroid plexus of rhombencephalon--in the zone of the angle formed by the tectum in choroid plexus and fundus of the IV ventricle. Comparison with the immunocytochemical study data with the mean number of nucleoli in epitheliocyte nuclei indicates that cells of choroid plexus epithelium leaving stage G of mitotic cycle and starting to differentiate have lower number of nucleoli than proliferating cells.