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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 56 (1991), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: We describe a simple, rapid, and efficient method, based on separation on a Percoll centrifugation gradient, to purify glial progenitor cells from newborn rat brains. Cytofluorimetry analysis of the isolated cell population showed that 75 ± 8 and 86 ± 7% of the cells were A2B5- and R24-positive, respectively. Transmission electron microscopy examination of the purified cell population confirmed their homogeneity and illustrated their typical morphology, as previously described in situ. Assay of UDP-galactose-ceramide galactosyltransferase, 3′-phosphoadenosine 5′-phosphosulfate galactosylceramide sulfotransferase, and 2′,3′-cyclic nucleotide 3′-phosphohydrolase activities showed that the levels of these enzymes were 446, 76, and 11 times lower, respectively, than the levels measured in mature oligodendrocytes. Low levels of mRNA coding for 2′,3′-cyclic nucleotide 3′-phosphohydrolase and myelin proteolipid protein, but not for myelin basic protein, were present in the glial progenitor cells. At the time of isolation, 40% of the cells in the population were dividing, and the cells could easily be expanded in culture. After 3 weeks of culture in the presence of 1% fetal calf serum, 75% of the cells had differentiated into galactosylceramide-positive oligodendrocytes. When the culture took place in the presence of 10% fetal calf serum, only 2% of the cells expressed galactosylceramide, and 60% were glial fibrillary acidic protein-positive astrocytes; half of them were also A2B5 positive.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: To characterize regulatory DNA sequences involved in oligodendroglial expression of myelin basic protein (MBP), transgenic mice carrying a 256 bp fragment of the mouse MBP promoter fused to an Escherichia coli lacZ gene were generated. Of four transgenic families, two (lines 2 and 4) expressed β-galactosidase activity in the nervous system but not in most other tissues. Histochemical and immunohistochemical analysis of adult brain from these two lines showed oligodendroglial-specific expression of the transgene. In line 2, only a small proportion of oligodendrocytes expressed the transgene, and in labelled cells the product of the enzymatic reaction with β-galactosidase was confined to a small round vesicle in the vicinity of the nucleus. In contrast, in tissue sections from line 4 adult brain and spinal cord β-galactosidase activity was much more intense and at least 80 – 90% of oligodendrocytes expressed the transgene. Detection of the MBP-lacZ transcript by in situ hybridization showed that the transgene mRNA was confined to the oligodendrocyte cell body. These results suggest that cis-acting regulatory elements, specifying oligodendrocytes identity, are located within 256 bp upstream from the MBP gene.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The dye Hoechst 33342 was combined with an immunodetectable transgene product (chloramphenicol acetyltransferase, CAT) expressed in differentiated oligodendrocytes to trace their fate after transplantation in the normal and the shiverer mouse brain. In the shiverer brain, the technique allowed us to visualize grafted cells inside myelin basic protein-positive myelin patches. Most of these cells were CAT-positive/Hoechst 33342-negative, reinforcing our hypothesis that cell division probably follows migration of grafted oligodendrocytes. Correlation of their morphology and distribution with their location in the host CNS suggested a local effect on the cell division and morphogenesis of the grafted material. When compared with transplantation of fragments of normal newborn donor tissue into the newborn shiverer brain, no difference could be seen between the behaviour of normal and transgenic oligodendrocytes. In the normal brain, transgenic oligodendrocytes survived at least 150 days and successfully myelinated the host axons. The timing of differentiation of grafted cells was similar in both types of recipient brains. Migration occurred rostrally and caudally. Although migrating cells could be observed along the meninges and the blood vessels, migration occurred preferentially along white matter tracts. The extent of migration was influenced by the site of implantation, and grafted cells could be found up to 6 mm from the grafting point. No differences in the timing of differentiation or the pattern or extent of migration could thus be demonstrated when transgenic oligodendrocytes were transplanted in the normal or the shiverer brain. This validates our previous studies using the newborn shiverer mouse as recipient.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0533
    Keywords: Key words Myelin basic protein ; Oligodendroglia ; Transplantation ; Freezing ; Cell storage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Human and mouse oligodendrocytes were transplanted, after a long period of cryostorage, into newborn mouse brain. Tissue fragments were obtained from brain and spinal cord of 10-week-old human fetuses and from the periventricular zone of embryonic and newborn mouse brains. Samples were stored at –180°C for periods of 3 days to over 5 years. Frozen or fresh fragments were transplanted into the brains of newborn shiverer mutant mice, which are deficient in myelin basic protein (MBP). Normal myelin, produced by grafted oligodendrocytes, was detected by immunohistochemistry with an anti-MBP antiserum. The best results were obtained with isospecific grafts. The timing of myelin appearance did not depend significantly on the species or age of the donor. Myelination obtained with mouse grafts was more profuse when the donor was younger (embryonic versus newborn). Cryopreservation over 5 years did not impede the graft's ability to produce myelin and can be considered for long-term storage of oligodendrocytes in view of cell therapy.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-0878
    Keywords: Lymphocytes ; Phytohemagglutinin stimulation ; Nucleolar organizer region ; Three-dimensional reconstruction ; Ultrastructure ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural changes in the spatial organization of nucleolar DNA in lymphocytes during phytohemagglutinin (PHA) stimulation was studied in guinea pigs by means of oxidized diaminobenzidine (DAB) at low pH as a differentially contrasting stain for nucleic acids and by the use of reconstruction of serial sections. The extended DNA filaments situated inside the fibrillar area originate from a large aggregation of heterochromatin, which is closely associated with the nucleolus, and from the perinucleolar shell of condensed chromatin. It is suggested that these two distinct regions of chromatin might be associated with different functions.
    Type of Medium: Electronic Resource
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