Scanning electron microscopy of epiplexus macrophages (Kolmer cells) in the dog

Abstract

Young dogs (6-14 weeks) were perfused with buffered aldehydes by standard techniques. The inferior medullary velum and tela choroidea were removed intact from the fourth ventricle, post-osmicated, dehydrated, critical point dried, coated with palladium-gold and examined in a Cambridge Stereoscan S4 scanning electron microscope. Selected samples after thorough scanning were routinely prepared for transmission electron microscopy (TEM). This study depicts numerous epiplexus (Kolmer cell) macrophages that exhibit extreme polymorphism. Because of the pleomorphic nature of these cells and their processes, classification based on external morphology is not practical. TEM shows their internal structure to be that of a macrophage. Bleb-like structures and bulbous projections appear to emerge from certain ependymal cell surfaces which seem to be completely or partially devoid of cilia.

The Plexus Chorioideus in the Adult Goat: A Scanning Electron Microscope Study

“…The convex apical membranes of the PCH in the goats studied are covered with dense microvilli or thick, microvillus-like structures such as for example in dogs reported by Allen (1975), in rats by Yamadori (1972) and Chamberlain (1974). Masuzawa and Sato (1983) divided microvilli on the PCH into 1) symmetrically digitated and 2) short, round, almost club-like ones.…”

“…The presence of epiplexal (Kolmer's) cells as well as supraependymal cells in the ventricular system of the brain in foetuses or in the postnatal period of some species of mammals has been reported by more authors (Scott et al 1972(Scott et al , 1974Kit amura 1972;Hosoya and Fujita 1974;Chamberlain 1974;Bleier et al 1975;Allen 1975;Mestres and Breipohl 1976;Coates 1977;Ling 1983;Otani and Tanaka 1988). The outer morphology of these macrophage-like cells is polymorphous; this follows from the study of the above-mentioned authors as well as from our results and not only in sheep and goat foetuses (R ajtová 1997) but also in the adult goats studied.…”

“…The spherical protrusions on the PCH surface have been recorded by more authors (e.g. Santolaya and Rodriguez Echandia 1968;Clementi and Marini 1972;Peters 1974;Scott et al 1974;Allen 1975;Coates 1977;Rajtová 1997) and all the authors consider them as a manifestation of the secretory activity of PCH.…”

“…The outer morphology of these macrophage-like cells is polymorphous; this follows from the study of the above-mentioned authors as well as from our results and not only in sheep and goat foetuses (R ajtová 1997) but also in the adult goats studied. Clementi and Marini (1972) in the cat, Hosoya and Fujita (1973) in the rat or Allen (1975) in the dog described two types of epiplexal cells: those with fibrous processes and those with pseudopodia. These data correspond to those in adult goats where EPC with pseudopodia prevailed.…”

Epiplexus cells in the embryos of the turtle, Trionyx sinensis.

“…Much of the information on epiplexus cells in the cerebral ventricles has been derived from the observations made on the materials of mammalian species using transmission and scanning electron microscopy (CARPENTER, MCCARTHY and BORISON, 1970;HOSOYA and FUJITA,1973;CHAMBERLAIN, 1974;PETERS, 1974;ALLEN, 1975;STURROCK, 1978STURROCK, ,1979ZING, 1979ZING, , 1981ZING, , 1983), yet the first description of these cells was by KoLMER (1921) and subsequently by ARIENS-KAPPERS (1953) in lower vertebrates mainly in amphibians especially in salamanders.…”