WILBERT

Wildauer Bücher+E-Medien Recherche-Tool

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 188 (1907), S. 65-87 
    ISSN: 1432-2307
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 363 (1993), S. 166-169 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] We previously reported that fos-lacZ was expressed, apparently continuously, in cell populations undergoing ter-minal differentiation culminating in death in skin, hair follicle and bone6. These and other results7'10 prompted us to examine other sites of naturally occurring cell death. In the ...
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 197 (1997), S. 9-29 
    ISSN: 1432-0568
    Keywords: Key words Cerebellum ; Dendritogenesis ; Filopodia ; Growth cone ; L7 ; Polarization ; Purkinje neuron ; Synaptogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Cerebellar Purkinje cells (PC) display a highly distinctive form of polarity. We have cultured murine PCs from dissociated E16 cerebellar anlagen for 1 week to investigate the early stages of neuronal compartmentalization and synaptic interactions, features which are important for the establishment of neuronal polarity. To unequivocally identify the PCs we utilized light and electron microscopic immunocytochemistry with an antiserum to the cell class-specific marker L7/pcp2 gene product. The PCs typically show a single, long axon, numerous short appendages classified as filopodia and protospines, and a small number of protodendrites. The nucleus is positioned asymmetrically in both the horizontal and vertical axes of the soma. The Golgi apparatus, coated and uncoated vesicles, and mitochondria are prominent ultrastructural features, while the endoplasmic reticulum is highly fragmented. The cell body receives rudimentary synapses on its smooth surfaces and appendages and no consistent morphological differences were detected between these elementary contacts. The axon is clearly identifiable; it emanates from either the cell body or a protodendrite, bifurcates at predominantly right angles, forms beaded collaterals, and terminates with relatively large growth cones. The varicosities of the PC axon contain pleomorphic synaptic vesicles and form rudimentary synapses primarily with the dendritic shafts of immunonegative neurons. The protodendrites are short, quickly tapering and sparsely branched; they emit numerous filopodia and immature spines and terminate with small growth cones. Rudimentary synapses are received on the proximal dendritic shafts and filopodia, and more mature synapses occur frequently on protospines. With few exceptions, PCs lie atop an astrocytic bed layer and glial processes are apposed to the various aspects of the PC body left free by the afferent axons. By contrast, PC processes are largely free of glial sheaths. We conclude that the ”stellate stage” of PC development in situ is replicated rather faithfully in culture and that PCs have established polarity and have begun to form intercellular contacts by 1 week in vitro. Moreover, the PCs are already morphologically distinct from other cell types in the 1-week cultures, although they have yet to develop the differentiated features that distinguish mature PCs.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 197 (1997), S. 31-50 
    ISSN: 1432-0568
    Keywords: Key words Purkinje neuron ; Synaptogenesis ; Dendritogenesis ; L7 ; Cerebellum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The morphological differentiation of E16 murine Purkinje cells (PCs) in dissociated cerebellar cultures was analyzed by light and electron microscopic immunocytochemistry after 2–5 weeks in vitro (wiv), with particular emphasis on dendritic differentiation, synaptic maturation, and formation of stereotypical fine structural features. This study complements a companion paper on the features of PCs after 1 wiv. After 2 wiv, the PCs have an eccentric nucleus and the cytoplasmic organelles appear immature; the axon has a distinct initial segment and beaded axon collaterals but its boutons still contain sparse synaptic vesicles; dendrites show few bifurcations and tufts of spiny branchlets. After 3 wiv, the PCs display a centered nucleus, an extensive hypolemmal cisternal system, and stacks of up to four cisterns of granular endoplasmic reticulum; there is an increased number of dendritic bifurcations, spiny branchlets, mature spines, and axonal branches; dendritic tips still contain vesicle clusters, suggesting growth, and many synapses and afferent boutons continue to display immature features. After 4 wiv, elaborate perinucleolar coiled body rosettes, subsurface cistern-mitochondrion complexes and large stacks of granular endoplasmic reticulum finally appear within the soma; dendrites show a further increase in the numbers of bifurcations, segments and spines; most spines are synaptic and show mature features; afferent synapses are differentially distributed; PC boutons consistently display mature features and show a considerable degree of target specificity, although naked spines and reduced glial sheaths persist. After 5 wiv, PCs do not show further maturation and some dystrophic features appear. We conclude that under standard conditions and despite the disruption of normal tissue organization, PCs in dissociated cultures differentiate maximally after 4 wiv, at which stage they display many of the light and electron microscopic features that characterize mature PCs in situ. This prolonged developmental time-frame resembles that in the normal cerebellum. In view of the increasing usage of dissociated cerebellar cultures to study aspects of neuronal differentiation, synaptic activation and neuronal-glial interactions, an elucidation of the neurocytology of dissociated cerebellar cultures as presented in this study provides important clues for the interpretation of experimental data.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Mice deficient for the chemokine receptor CXCR4 show premature translocation of granule cell neuroblasts from their germinal zone into the nascent cerebellum [Y.-R. Zuo et al. (1998)Nature, 393, 595–599]. Here, we used CXCR4-null mice to analyse the early development of cerebellar cortical inhibitory interneurons and pontine neurons which, in the adult, are synaptically integrated with granule cells. Cortical inhibitory interneuronal precursors normally invade the cerebellar anlage of CXCR4-deficient mice, but their dispersal is impeded by dislocated foci of proliferating granule cells, from which they are excluded. This is reminiscent of the strict exclusion of inhibitory interneuronal precursors from the superficial external granule cell layer. As inhibitory interneuronal precursors readily mingle with post-mitotic granule cells both in wild-type and CXCR4-null mice, these findings indicate that the developmentally regulated interactions between granule and inhibitory interneuronal precursors are independent of SDF-1/CXCR4 signalling. In contrast, the transit of pontine neurons from the rhombic lip through the anterior extramural stream to the basilar pons is disrupted in CXCR4-deficient animals. Migrating pontine neurons express CXCR4, and in CXCR4-null animals these cells are found displaced deep into the brainstem. Consequently, nascent pontine nuclei in CXCR4-deficient animals are hypoplastic. Moreover, they fail to express plexin D1, suggesting that SDF-1/CXCR4 signalling may also impinge on axon guidance critical to the orderly formation of granule cell mossy fibre afferents.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Vasopressin and oxytocin genes are expressed in mutually exclusive sets of magnocellular neurons in the hypothalamus. Cell specificity and regulation are probably controlled by extra- and intracellular signals acting on one or the other gene. In order to identify factors that regulate peptide expression, we have used primary dissociated cultures derived from 14-day old foetal rats. Vasopressin expression was monitored by combined immunocytochemistry and in situ hybridization. Treatment of cultures with forskolin and/or the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX), both of which result in elevated intracellular cyclic AMP levels, increased the numbers of vasopressin-expressing cells up to 10-fold. The specific Vasopressin messenger ribonucleic acid accumulation was verified quantitatively by ribonuclease protection assays. Forskolin and IBMX did not change the levels of the general neuronal markers, neuron-specific enolase and synaptophysin, suggesting that the effect of these drugs was specific for vasopressin-expressing cells. The drugs were not mitogenic for magnocellular neurons. Furthermore, their effect was not mediated trans-synaptically, as the drugs were also effective in cultures grown in low Ca2+/high Mg2+ medium, as well as in cultures treated with either tetanus toxin or tetrodotoxin. The presence of putative response elements for the transcription factor AP-2 in the 5’promoter regions of all vasopressin genes sequenced so far may provide the molecular basis of the observed cyclic AMP effect. No such elements are present in the genes for oxytocin, the messenger ribonucleic acid levels of which were not measurably affected by forskolin and IBMX in our cultures.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...