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  • 1
    ISSN: 1432-0878
    Keywords: Subcommissural organ ; Reissner's fiber ; Ependyma ; Secretory process ; Comparative analysis ; Immunocytochemistry ; Vertebrates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The subcommissural organs (SCO) of 76 specimens belonging to 25 vertebrate species (amphibians, reptiles, birds, mammals) were studied by use of the immunoperoxidase procedure. The primary antiserum was obtained by immunizing rabbits with bovine Reissner's fiber (RF) extracted in a medium containing EDTA, DTT and urea. Antiserum against an aqueous extract of RF was also produced. The presence of immunoreactive material in cell processes and endings was regarded as an indication of a possible route of passage. Special attention was paid to the relative development of the ventricular, leptomeningeal and vascular pathways established by immunoreactive structures. The SCO of submammalian species is characterized by (i) a conspicuous leptomeningeal connection established by ependymal cells, (ii) scarce or missing hypendymal cells, and (iii) a population of ependymal cells establishing close spatial contacts with blood vessels. The SCO of most mammalian species displays the following features: (i) ependymal cells lacking immunoreactive long basal processes, (ii) hypendymal secretory cells occurring either in a scattered arrangement or forming clusters, (iii) an occasional leptomeningeal connection provided by hypendymal cells, and (iv) in certain species numerous contacts of secretory cells with blood vessels. In the hedgehog immunoreactive material was missing in the ependymal formation of the SCO, but present in hypendymal cells and in the choroid plexuses. The SCO of several species of New-and Old-World monkeys displayed immunoreactive material, whereas that of anthropoid apes (chimpanzee, orangutan) and man was completely negative with the antisera used.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0878
    Keywords: Subcommissural organ ; Ependyma ; Comparative aspects ; Immunocytochemistry ; Secretory process ; Blood vessels
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In 76 specimens (amphibians, reptilians, mammals) belonging to 25 different vertebrate species, the region of the subcommissural organ (SCO) was investigated with the use of a primary antiserum raised against an extract of bovine Reissner's fiber+the immunoperoxidase procedure according to Sternberger et al. (1970). In the SCO of a toad (Bufo arenarum) and several species of reptiles (lacertilians, ophidians, crocodilians), the ependymal cells were the only type of secretory cell displaying vascular contacts, whereas in mammals ependymal and hypendymal cells established intimate spatial contacts with blood vessels. In Bufo arenarum, but especially in the reptilian species examined, the ependymo-vascular relationship was exerted by a population of ependymal cells having a rather constant location within the SCO and projecting to capillaries that showed a remarkably constant pattern of anatomical distribution. In the SCO of mammals the modality and degree of the structural relationships between secretory cells and blood vessels varied greatly from species to species. In the SCO of the armadillo and dog the secretory tissue was organized as a thick, highly vascularized layer with most of the cells oriented toward the capillaries. A rather opposite situation was found in the SCO of New-and Old-World monkeys, where vascular contacts were restricted to a few ependymal cells.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0878
    Keywords: Reissner's fiber ; Massa caudalis ; Subcommissural organ ; Spinal cord ; Central canal ; Immunocytochemistry ; Lectin histochemistry ; Lamprey ; Geotria australis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The subcommissural organ (SCO), Reissner's fiber (RF) and its massa caudalis of lamprey larvae (Geotria australis) were investigated immunocytochemically by use of an antiserum raised against bovine RF as primary antibody. The affinities of RF and massa caudalis for Ricinus communis agglutinin I (RCA) with and without previous acid hydrolysis, concanavalin A (Con A), wheat-germ agglutinin (WGA), aldehyde fuchsin, and PAS reaction were also studied. SCO and massa caudalis were strongly immunoreactive, whereas RF proper was distinctly negative. RF did not react with Con A and RCA. Only the periphery of RF was WGA-positive. RCA showed affinity for RF only after acid hydrolysis. RF was homogeneously stained by the aldehyde-fuchsin and PAS-methods. At variance with RF proper, the periphery of the massa caudalis reacted with RCA without previous acid hydrolysis, but its core was WGA-positive and reacted with RCA only after hydrolysis. It is suggested that (i) RF has a coat of glycoproteins containing sialic acid as terminal residue, whereas the massa caudalis possesses a coat with galactose as terminal residue; (ii) in RF proper and the massa caudalis the spatial arrangement of glycoproteins might be different. Routine transmission electron-microscopic observations indicate that in larvae of Geotria australis an open communication exists between the ampulla caudalis and blood capillaries via large cavities or lacunae.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0878
    Keywords: Subcommissural organ ; Glycoproteins ; Secretory process ; Immunocytochemistry ; Lectin histochemistry ; Rat ; Vertebrates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The subcommissural organ (SCO) of the rat was investigated by use of histochemical and immunocytochemical methods at the light and electron-microscopic levels. Consecutive thin methacrylate sections were stained with the pseudoisocyanin (Psi), immunoperoxidase (IMC; employing an antiserum against Reissner's fiber, AFRU), periodic acid-Schiff (PAS) and periodic acid-silver methenamine (SM) techniques, and reacted with six types of lectins. Psi, SM, concanavalin A (Con A) and IMC were also used for double and triple sequential staining of the same section. Increasing dilutions of AFRU (from 1∶1000 to 1∶200 000) were used for immunostaining of serial paraffin sections. In addition, ultrastructural localization of (i) Con A-binding sites and (ii) immunoreactive secretory material was performed. Some of these procedures were also applied to the ophidian and canine SCO. Con A-positive, Psi-positive and immunoreactive materials coexisted within the same cisternae of the rough endoplasmic reticulum. The Golgi apparatus lacked Con A-positive and immunoreactive substances. Apical secretory granules and secreted material lying on the surface of the SCO showed (i) the highest affinity for AFRU, but were (ii) Con A-negative, and (iii) wheat-germ agglutinin-, PAS and SM-positive. Reissner's fiber displayed a low affinity for AFRU. It is suggested that the SCO secretes N-linked glycoproteins, the carbohydrate and protein moeities of which undergo (i) a maturation process before being released, and (ii) some kind of modification(s) after their release into the ventricle. The perivascular secretory cells of the dog SCO might secrete a material different from that secreted by the ependymal cells.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 262 (1990), S. 105-113 
    ISSN: 1432-0878
    Keywords: Subcommissural organ ; Lectin histochemistry ; Immunocytochemistry ; Glycoproteins ; Human fetuses ; Bovine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The subcommissural organ (SCO) of 7 human fetuses, 3 to 6.5 months old, was investigated by means of: (i) immunocytochemistry employing three different antisera against secretory products extracted from the bovine SCO and Reissner's fiber; (ii) lectin binding using concanavalin A (Con A; affinity: mannose, glucose), wheat-germ agglutinin (WGA; affinity: N-acetyl-glucosamine, sialic acid), and Limax flavus agglutinin (LFA; affinity: sialic acid). Sections of bovine SCO were processed simultaneously and examined for comparative purposes. The human fetal SCO displayed lectin-binding properties identical to those in the SCO of other mammals. Thus, Con-A-binding sites were restricted to abundant supranuclear structures that most likely corresponded to the rough endoplasmic reticulum, but were missing from granules located in the apical cytoplasm. The latter secretory material was strongly WGA- and LFA-positive and formed a distinct zone in the most apical portion of the ependymal cells. In contrast, this type of reactivity was missing in the adjacent cells of ependyma proper. In the bovine SCO, LFA-positive granules were also aggregated in an apical layer. The secretory material in the bovine SCO, especially its apical granular component, was strongly immunoreactive with the three antisera used; the human fetal SCO, however, lacked this immunoreactivity. It is postulated that the SCO of human fetuses secretes glycoproteins with a carbohydrate chain similar to-and a protein backbone different from-the secretions elaborated by the SCO of other vertebrate species.
    Type of Medium: Electronic Resource
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