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

Ling, Eng‐Ang; Gopalakrishnakone, P.; Voon, F. C. T.

doi:10.1679/aohc.48.355

Cited by 5 publications

(5 citation statements)

References 9 publications

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“…In this connection, Allen (1975) had drawn attention to the extreme polymorphic nature of the epiplexus cells in dog. In our studies in turtle (Ling et al, 1985a), rat (Ling et al, 1985b), cat (Ling et al, 1988), and monkey (Ling, 1983), the epiplexus cells displayed diverse morphological forms: round, stellate, and bipolar (Fig. 3).…”

Section: Scanning Electron Microscopymentioning

confidence: 82%

Origin, nature, and some functional considerations of intraventricular macrophages, with special reference to the epiplexus cells

Ling

Kaur

1998

Microsc. Res. Tech.

103

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Intraventricular macrophages encompass the supraependymal, free‐floating, and epiplexus (Kolmer) cells; the supraependymal cells lie in close apposition to the ventricular ependyma, the epiplexus cells are closely associated with the choroid plexus epithelium, and the free‐floating cells are at a variable distance from the epithelial surface. Although the three cell types are regarded as one cellular entity, the epiplexus cells preponderate. On scanning electron microscopy, the epiplexus cells display diverse morphological forms, ranging from round to bipolar to stellate, and bear a variable number of cytoplasmic processes. Transmission electron microscopy shows the presence of large numbers of lysosomes. The phagocytic nature of epiplexus cells is shown by their intense staining for nonspecific esterase and active uptake of tracers, e.g., horseradish peroxidase and rhodamine isothiocynate, administered intravenously or intraperitoneally. The mode of entry of these tracers in the cerebral ventricles is by way of transepithelial transport. In rats, the population of intraventricular macrophages increases steadily after birth until 17 days of age; thereafter, their cell population remains relatively unchanged. The early upsurge is attributed to proliferation of residential cells and/or influx of circulating monocytes/stromal macrophages through the process of “emperipolesis.” The immunophenotypic features of intraventricular macrophages are consistent with other mononuclear phagocytes being immunoreactive for OX‐42, OX‐18, OX‐6, and OX‐1 and ED1 for the detection of CR3 receptors, MHC class I and II antigens, leucocyte common antigen, and macrophage antigen, respectively. The expression of these antigens is noticeably enhanced following the injection of lipopolysaccharide (LPS) into postnatal rats. Remarkably, the intraventricular macrophages are induced to express MHC class II (Ia) antigen after LPS or interferon‐γ injections. Furthermore, the expression of transferrin receptors as detected with OX‐26 is also upregulated after these treatments. Epiplexus cells are also elicited to display a de novo expression of nitric oxide synthase‐like immunoreactivity following intracerebral injection of LPS. They also respond vigorously to a single nonpenetrative blast. Results of our series of studies suggest that, besides their primary function as scavenger cells, the intraventricular macrophages partake in possible immunological responses and iron regulation in the ventricular system or the brain as a whole. Microsc. Res. Tech. 41:43–56, 1998. © 1998 Wiley‐Liss, Inc.

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Section: Scanning Electron Microscopymentioning

confidence: 82%

Origin, nature, and some functional considerations of intraventricular macrophages, with special reference to the epiplexus cells

Ling

Kaur

1998

Microsc. Res. Tech.

103

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“…Supraependymal cells, epiplexus cells, and free cells in the ventricles (Kolmer, 1921) are mainly phagocytic cells (Bleier, 1977a;Bleier et al, 1975;Carpenter et al, 1970;Ling et al, 1985a), with the exception of some supraependymal cells located in discrete areas of the third ventricle which have been identified as neurons (Card and Mitchell, 1978). Supraependymal phagocytic cells are thought to derive from mononuclear phagocytes or circulating monocytes (Bleier, 1977b) and perhaps also from ependymal cells or from microglia-like cells within the brain (Mestres and Breipohl, 1976;Sturrock, 1978).…”

Section: Relationship Between Supraependymal Cells and Microgliamentioning

confidence: 99%

Transitory disappearance of microglia during the regeneration of the lizard medial cortex

López‐García

Nácher

Castellano

et al. 1994

Glia

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In normal lizards, microglial cells populate the medial cortex (a zone homologous to the hippocampal fascia dentata), with a preferential distribution along the border between the granular cell layer and the plexiform layers. Intraperitoneal injection of the neurotoxin 3-acetylpyridine (3AP) induces a selective lesion in the medial cortex with a rapid degeneration of the granular layer and its zinc-enriched axonal projection. Within 6-8 weeks, the granular layer is, however, repopulated by a new set of neurons generated in the subjacent ependyma and the cell debris is removed. The aim of this study was to determine to what extent microglia were involved in the scavenging processes during the regeneration process. To this end we studied the brains of regenerating lizards at different times after 3AP lesion, visualising microglial cells by the nucleoside diphosphatase (NDPase) histochemical reaction. Surprisingly, we found that stained microglial cells disappeared 6-8 hours after 3AP injection and remained absent until 10-15 days after injection. One month postlesion an increased population of microglial cells was found scattered throughout all plexiform layers of the cortex. Thorough examination of semithin and ultrathin sections confirmed the absence of microglia in the medial cortex of recent lesioned animals but the presence of an exuberant population after 1 month postlesion. In the tissue, phagocytotic scavenging was carried out by radial ependymocytes, not by microglia.

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“…Some prominent attributes of trionychids have never been used in an embryonic staging series (e.g., lips along the upper and lower jaws), but there are few published studies involving embryonic trionychids. Ling et al (1985) did not stage embryos of the Asian trionychid Pelodiscus sinensis in their study of epiplexus cells; embryonic age (in days) was used in place of a staging scheme. Cherepanov (1995) referred to ranges of Yntema stages (e.g.,[18][19][20][21] in a study of shell development in the same species.…”

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confidence: 99%

Staging criteria for embryos of the spiny softshell turtle,Apalone spinifera(testudines: Trionychidae)

Greenbaum

Carr

2002

Journal of Morphology

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Previous work describing the embryonic stages of turtle development has not included members of the highly derived trionychid turtles. Staging criteria are described for the spiny softshell turtle (Apalone spinifera) to facilitate comparisons between phylogenetically distant taxa of turtles. Embryonic development in A. spinifera is placed in the context of the widely used sequence of Yntema stages. Novel features are included in the descriptions of staging criteria for Stages 13-26. Comparisons of the development of specific features are made between A. spinifera and other taxa of turtles. Data on the duration of developmental stages at different temperatures and embryo dimensions support the conclusion that morphology-based staging criteria are superior to developmental rate temperature coefficients.

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

Cited by 5 publications

References 9 publications

Origin, nature, and some functional considerations of intraventricular macrophages, with special reference to the epiplexus cells

Origin, nature, and some functional considerations of intraventricular macrophages, with special reference to the epiplexus cells

Transitory disappearance of microglia during the regeneration of the lizard medial cortex

Staging criteria for embryos of the spiny softshell turtle,Apalone spinifera(testudines: Trionychidae)

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