Glial fibrillary acidic protein in radial glia of early human fetal cerebrum: a light and electron microscopic immunoperoxidase study.

In order to assess the nature of glial fibrillary acidic protein (GFAP) immunoreactivity in the radial glia of early human fetal cerebrum, full thickness blocks from the midconvexity of the frontoparietal region of the cerebrum of 25 human fetuses ranging from ten to 20 weeks of ovulation age were studied by light and electron microscopic (EM) immunoperoxidase methods. The presence of GFAP within radial glia was demonstrated in vibratome sections, in de-eponized 1 micron sections and in paraffin-embedded sections both at light and EM levels in suitably fixed human fetal cerebral tissue. The results indicate that the pattern of GFAP immunoreactivity observed in "routinely" processed autopsy brains, in which fixation is suboptimal, must be interpreted with care.