Biomedical subjects
E Bascó
Publications and source records attributed to E Bascó.
Transport of horseradish peroxidase by processes of radial glia from the pial surface into the mouse brain.
The transport of horseradish peroxidase (HRP) applied to exposed pial surfaces of the brain was studied in newborn, 4-, 7- and 12-day-old, and adult mice. In the telencephalon the cell bodies of radial glia were found to accumulate the tracer. Labeled cells occurred in the subventricular zone of the lateral ventricle during the first postnatal week; they became gradually restricted to an area around the stria terminalis (ventrolateral ventricular corner) by day 12. At later stages no HRP transport could be traced from the surface of the telencephalon. In the cerebellum, HRP was transported from the surface to the cell bodies of Bergmann glia in all age groups studied including adult animals. It is concluded that radial glia and their derivatives share the capacity of transporting material between various cerebrospinal fluid compartments.
Immunocytochemical demonstration of glial fibrillary acidic protein in mouse tanycytes.
Immunohistochemical techniques were used to stain for the astrocytespecific glial fibrillary acidic protein (GFAP) in the cells lining the third ventricle of the developing and mature mouse brain. Before birth immunoreactive tanycytes were only observed in the infundibular recess of the median eminence, where they could first be seen at embryonic day 17. They possessed long processes running towards the ventral surface on the brain. During the early postnatal period GFAP-positive tanycytes gradually appeared throughout the third ventricle, although the ependymal cells themselves remained unstained. The tanycytes retained thier immunoreactivity for anti-GFAP serum in the adult, and were also evident in the adult rat third ventricle indicates that they, the transient radial glia of the developing cerebral cortex, the persistent Bergmann glia of the cerebellum, similar astrocytes with radial processes in the hippocampal dentate gyrus and conventional astroglia are all closely related cell types.
Radial glia in the developing mouse cerebral cortex and hippocampus.
The regional distribution of radial glia in the developing cerebral cortex and the hippocampus of the mouse was studied using silver impregnation and immunocytochemical staining for glial fibrillary acidic protein (GFAP). Whilst the former technique revealed radial fibres at a slightly earlier age, immunocytochemistry gave a better picture of their general distribution and enabled systematic study of the appearance and disappearance of GFAP-positive radial glia throughout the cortex. Although a clear association between migrating neurones and radial glia was evident in the later stages of cortical plate formation, this relationship was not apparent in all cortical regions nor at the very early stages of the formation of the cortical plate. Even after allowing for a delayed appearance of GFAP immunoreactivity in relatively mature radial glia, the uneven distribution of these cells, their appearance after the cortical plate has already been formed, and their regional development in a pattern dissynchronous with that of the cortical plate argue against a general role of these structures in neuronal migration in the mouse, although there are notable phylogenetic differences.
The types of proliferating glioblasts in the immature mouse neocortex and dentate gyrus as revealed by electron microscopic autoradiography.
Proliferating glial elements of 3 to 12-day-old mouse parietal cortex and dentate gyrus were investigated by the electron microscopic autoradiography of 3H-thymidine. The presence in these regions of three types of proliferating glial precursors was verified and related to astrocyte development. Comparing the two areas studied it was concluded that postnatal glial proliferation is independent from neurogenesis and that astroglia is capable of proliferation even in advanced stages of differentiation.
Proliferation of astroglia in the embryonic mouse forebrain as revealed by simultaneous immunocytochemistry and autoradiography.
Proliferating glial precursors of the embryonic mouse forebrain were labelled with [3H] thymidine autoradiography and immunostained in the same preparation by using antibodies raised against astroglia-specific protein (GFAP). Results indicate that mature fibrous forms of astroglia are capable of proliferation.
Regional distribution and time course of mitotic activity of astroglia in the immature mouse forebrain.
The regional distribution of mitotic figures in the immature mouse forebrain was mapped at various early postnatal periods up to P12, to determine the regional time courses of early postnatal cell proliferation. Mitotic figures seen outside the germinal layers appeared to be astroglial precursors; their postnatal proliferation was found to follow a well-defined regional programme.
Identification of early glial elements as the precursors of Bergmann-glia: a Golgi-analysis of the developing rat cerebellar cortex.
The developing rat cerebellar cortex was studied by the rapid Golgi procedure in 200 mu thick slices and in 1--2 mu thick semithin sections poststained with toluidine-blue. Glial cells having radial fibres directed towards the pial surface were found to be present continuously in the internal granular layer during cerebellar maturation. This cell type was identified as the developing Bergmann-glia.
The effect of thyroid hormone on the formation of rat cerebellar Bergmann-glia.
H3-thymidine incorporating cells were demonstrated by autoradiography in the developing cortex. Before the 7-8th days labelled cells were distributed throughout the full width of the internal granular layer. Between days 8 to 14 they were found exclusively in the ganglionic layer and were identified as Bergmann-glia. Thyroid hormone treatment brought about an earlier shift of the label to the ganglionic layer indicating an acceleration of Bergmann-glia formation. Since the acceleration coincided with the known accelerating effect of thyroid hormone on granule cell migration, a causal relationship is assumed between Bergmann-glia formation and granula cell migration.
Proliferation of Bergmann-glia in the developing rat cerebellum.
Mitotic cells in the ganglionic layer of the infant rat cerebellum were studied between 3 to 12 postnatal days. The connection of these cells with the radial glial fibers of the primitive molecular layer could be established. On this basis it was assumed that the mitotic cells studied were immature Bergmann-glial cells whose proliferative activity seemed to continue even after the formation of their characteristic radial fibers. This phenomenon might offer an explanation for the divergent views on the generation time of Bergmann-glia.