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  • 1
    Electronic Resource
    Electronic Resource
    Diffusion barrier properties of the perineurium: an in vivo ionic lanthanum tracer study (1989)
    Springer
    Anatomy and embryology 180 (1989), S. 237-242 
    Details
    ISSN: 1432-0568
    Keywords: Perineurium ; Lanthanum ; Diffusion barriers ; In vivo ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary While the perineurium as a diffusion barrier has been extensively investigated by light and electron microscopy, copy, such studies have been largely restricted to the use of protein tracers. In the present study the permeability of the perineurium to a physiologically more relevant ionic tracer has been assessed. In vivo the rat sural or tibial nerve was either microinjected with lanthanum nitrate solution for endoneurial application or bathed in the lanthanum solution for epineurial application. The findings generally demonstrated an effective barrier to the tracer which failed to penetrate the inner layers of the perineurium. Only at the highest lanthanum concentration and longest time intervals employed did trace quantities occasionally penetrate the barrier and then only in the presence of some cytopathological changes to the outermost perineurial cells. The usefulness of the microinjection method was limited by the slight but unavoidable trauma to the perineurium. The findings are related to those of other studies which have used electron dense tracers, also to studies using physiological including electrophysiological techniques and morphological including freeze-fracture methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00315882
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  • 2
    Electronic Resource
    Electronic Resource
    Cerebral and pial microvessels: differential expression of γ-glutamyl transpeptidase and alkaline phosphatase (1999)
    Springer
    Anatomy and embryology 199 (1999), S. 29-34 
    Details
    ISSN: 1432-0568
    Keywords: Key words γ-Glutamyl transpeptidase ; Alkaline phosphatase ; Blood-brain barrier ; Pial microvessels ; Astrocytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Pial microvessels have several important blood-brain barrier (BBB) characteristics in common with cerebral microvessels, despite lacking their astrocytic ensheathment. We have therefore determined whether they have the same distribution of two enzymes, γ-glutamyl transpeptidase (GGTP) and alkaline phosphatase, both of which are known to be astrocyte-dependent. GGTP was absent from all rat pial microvessels but strongly present in brain cortical capillaries. Alkaline phosphatase was heterogeneously expressed in pial microvessels, including capillaries, but strongly positive in brain cortical capillaries. Diffusible, inductive factors produced by astrocytes could account for these differences in enzyme distribution between the two vessel types. Furthermore, differences in expression between the two markers may reflect their differing sensitivities to the astrocytic factors. Caution is urged in the common usage of the pial microvessel as a model system in BBB studies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004290050206
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  • 3
    Electronic Resource
    Electronic Resource
    Axonal microtubules: a computer-linked quantitative analysis (1985)
    Springer
    Anatomy and embryology 171 (1985), S. 339-344 
    Details
    ISSN: 1432-0568
    Keywords: Microtubules ; Myelinated axons ; Morphometry ; Computer analysis ; Literature review
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Employing current computer-aided morphometric techniques, axonal microtubule density was determined for the rat sural nerve. Analysis of extensive data showed that while microtubule number increases with axon size, the increase is not directly proportional. Thus the relationship between microtubule density and axonal size is inversely related, so that microtubule density is greater in smaller axons than in larger axons. When a proximal and distal site, separated by 2 cm, were compared for microtubule density there was no significant difference, using pooled data for all fibre diameters. The results are interpreted in terms of our present knowledge of axonal-microtubule quantitative relationships, which is reviewed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00347022
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  • 4
    Electronic Resource
    Electronic Resource
    A comparison of blood-brain barrier and blood-nerve barrier endothelial cell markers (1999)
    Springer
    Anatomy and embryology 199 (1999), S. 509-517 
    Details
    ISSN: 1432-0568
    Keywords: Key words Blood-brain barrier ; Blood-nerve barrier ; Endothelial cell ; Membrane markers ; Inductive mechanisms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  A number of major properties of endothelial cells (EC) at the blood-brain barrier (BBB) have been shown to be astrocyte-dependent. Whether analogous properties at the blood-nerve barrier (BNB) are induced and maintained by Schwann cells has not been investigated. As a preliminary investigation we have undertaken a comparative study of six EC membrane markers at the BBB and BNB and perineurium. Employing immunoblotting and immunocytochemistry the relative distribution between rat brain cortex and sciatic nerve was determined for the glucose transporter (GLUT-1), the transferin receptor (OX-26), the endothelial barrier antigen (EBA) and the OX-47 antigen. Using enzyme cytochemistry the same comparison was made for γ-glutamyl transpeptidase (GGTP) and alkaline phosphatase. By immunocytochemistry GLUT-1 was uniformly strongly represented in brain EC, nerve EC and perineurium. OX-26 was strongly positive in brain EC but present only in trace quantities in nerve EC and perineurium. EBA similarly showed strong positivity in brain EC and trace amounts in nerve EC but was absent from perineurium. OX-47 was present moderately in brain EC and perineurium but absent from nerve EC. Quantitative immunoblotting of brain and sciatic nerve homogenates showed statistically significant differences in the level of expression of EBA and OX-26 between the two tissues. Enzyme cytochemistry showed that GGTP was strongly positive in brain EC but absent from nerve EC and perineurium. Alkaline phosphatase stained strongly in brain and nerve EC and was absent from perineurium. In summary the six membrane markers were heterogeneously represented in nerve compared with brain. This pattern of distribution in the nerve cannot simply be accounted for by the absence of astrocytes and their inductive influences. Any inductive influences of Schwann cells require investigation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004290050248
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  • 5
    Electronic Resource
    Electronic Resource
    A study of the capacity of myelinated and unmyelinated nerves to induce experimental allergic neuritis (1972)
    Springer
    Acta neuropathologica 21 (1972), S. 99-108 
    Details
    ISSN: 1432-0533
    Keywords: Experimental Allergic Neuritis ; Unmyelinated “Antigen” ; Schwann Cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The capacity of myelin-free Schwann cells to induce EAN was investigated. Human foetal peripheral nerve and human adult abdominal vagus nerve, both containing little or no myelin, failed to induce EAN when injected intradermally (together with Freund's adjuvant) into rabbits. In contrast, human adult sciatic nerve, which is heavily myelinated, induced characteristic signs and histopathology of EAN. Thus in the “myelin-free” “antigens” Schwann cell plasma membrane, from which myelin is apparently derived, failed to induce EAN. Reasons for this paradox are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687564
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  • 6
    Electronic Resource
    Electronic Resource
    A study of the perineurium in peripheral nerve pathology (1975)
    Springer
    Acta neuropathologica 33 (1975), S. 257-270 
    Details
    ISSN: 1432-0533
    Keywords: Perineurium ; Pathology ; Electron microscopy ; Homeostasis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The response of the perineurium to the following experimental systems was investigated by light and electron microscopy: nerve crush, cold lesion and microinjection of (a) histamine liberator, (b) potassium cyanide, (c) lysophosphatidyl choline (LPC). Where myelin breakdown occurred, lipid globules were seen within Schwann cells, macrophages and also perineurial cells. Where increased vascular permeability occurred, proteinaceous material leaked from endoneurial vessels into the endoneurial space and later appeared between perineurial laminae. It is suggested that the normal homeostatic function of the perineurium is extended in pathology to the removal of protein and lipid debris. In this way the perineurium contributes to the restoration of the normal microenvironment of peripheral nerve fibres.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00688398
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  • 7
    Electronic Resource
    Electronic Resource
    Regeneration of the node of Ranvier: a light and electron microscope study (1977)
    Springer
    Acta neuropathologica 37 (1977), S. 153-163 
    Details
    ISSN: 1432-0533
    Keywords: Node of Ranvier ; Microscopy ; Wallerian degeneration ; Internodal lengths
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Regeneration of the node of Ranvier was investigated in the rat peroneal nerve 10–60 days after nerve crush, by light and electron microscopy. At 10 and 20 days after crush nodes of Ranvier were clearly identifiable by electron microscopy but had a relatively simple structure. At 40 days after crush however nodes were highly differentiated showing specialised features such as paranodal bulbs, nodal constriction of the axon, paranodal Schwann cell mitochondria, nodal Schwann cell microvilli, and nodal gap substance. By light microscopy some nodes were identifiable as early as 20 days after crush. At both 30 and 60 days after crush regenerated internodes were uniformly short (means of 275 μm and 339 μm respectively).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00692061
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  • 8
    Electronic Resource
    Electronic Resource
    The node of ranvier in early wallerian degeneration: A freeze-fracture study (1981)
    Springer
    Acta neuropathologica 54 (1981), S. 95-100 
    Details
    ISSN: 1432-0533
    Keywords: Ranvier node ; Wallerian degeneration ; Freeze fracture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Using the freeze-freeze-fracture technique, the sciatic nerve of the rat and rabbit was examined distally at 24 h after crush, with particular reference to the node of Ranvier and paranode. The paranodes, in the majority of myelinated fibres, showed a loss of the cytoplasmic circumferential bands and longitudinal columns and their associated membrane pores which characterise the normal Schwann cell surface. Axonal changes consisting of accumulations of axoplasmic organelles occurred at both the node and paranode. At the nodes large intramembraneous partiles in the axolemma (E face) appeared unchanged. Nodal Schwann cell microvilli and paranodal myelin terminal loops were generally unaffected. The findings are discussed in terms of the decrease in amplitude of the action potential which occurs in early Wallerian degeneration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00689401
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  • 9
    Electronic Resource
    Electronic Resource
    Filipin-sterol complexes at Schmidt-Lanterman incisures (1987)
    Springer
    Acta neuropathologica 72 (1987), S. 355-361 
    Details
    ISSN: 1432-0533
    Keywords: Filipin ; Cholesterol ; Schmidt-Lanterman incisures ; Myelin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Employing the freeze-fracture technique, the distribution of filipin-sterol complexes was determined for membranes of peripheral nerve myelin. A heterogeneous distribution of complexes was observed with the greatest abundance on membranes associated with the cytoplasmic channels of Schmidt-Lanterman and longitudinal incisures. In addition there was an irregular network of well-labelled membrane bands in compact myelin. The results are related to a possible role for these channels and bands in the biochemical turnover of cholesterol in myelin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687267
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  • 10
    Electronic Resource
    Electronic Resource
    Schmidt-Lanterman incisures (1980)
    Springer
    Acta neuropathologica 52 (1980), S. 97-104 
    Details
    ISSN: 1432-0533
    Keywords: Schmidt-Lanterman incisures ; Sural nerve ; Remyelination ; Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A mechanism has been proposed previously for the formation of Schmidt-Lanterman incisures during ontogeny as myelinated nerve fibres increase in diameter. In this study, the mode of formation of incisures and their development were examined by light and electron microscopy in remyelinating fibres (16–200 d) of the sural nerve of rats following lysophosphatidyl choline (LPC)-induced segmental demyelination. In remyelination, a basic number of incisures is incorporated into the myelin sheath ab initio. Apparently these incisures which are at first circumferentially incomplete, being localised to the region of the mesaxons, progressively extend around the whole circumference of the myelin sheath. As fibre diameter increases, additional incisures are added, seemingly, by the intrusion of Schwann cell cytoplasm between the compact myelin lamellae, from the abaxonal side of the myelin sheath. The progressive differentiation of incisures is described in terms of their complement of organelles. The results are discussed with reference to the possible functions of incisures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00688006
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