Figure 8. Identification of proliferating cell types with TEM.

Autoradiography on animals sacrificed 1 hour after [³H]thymidine injection. Labeled cells were identified on toluidine blue-stained semithin sections (A-D, arrows), serial ultrathin sectioned and analyzed under the TEM (E–T). Electronmicrographs of cells pointed with an arrow and depicted in orange are shown. A) Labeled Ecc cell (E and I), showing apically two large and electron-dense basal bodies (M). In a different section, the 9+2 microtubule structure of the cilium can be observed (Q, arrowhead). B) A different biciliated Ecc cell identified on a longitudinal section (F and J). It shows a radial expansion (J, arrow) and two cilia cut longitudinally (N). Other sections of the reconstruction showed dense particles close to the basal bodies (R, arrowheads). C) Uniciliated Ecc cell labeled on a longitudinal section (G and K). The cell showed apically a cilium with a large electron-dense basal body (O) and 9+2 microtubule structure (S, arrowhead). D) Frequently, labeled ependymal cells (H and L) contained apically basal body portions and electron-dense particles (P and T, arrowheads). Scale bar in A (A–H), 10 µm; I (I–L), 5 µm; M (M–O and Q–S), 500 nm; P (P and T), 1 µm.