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  • 1
    Electronic Resource
    Electronic Resource
    Freeze-fracture observations on normal and abnormal human perineurial tight junctions: alterations in diabetic polyneuropathy (1991)
    Springer
    Acta neuropathologica 81 (1991), S. 269-279 
    Details
    ISSN: 1432-0533
    Keywords: Peripheral nerve ; Human diabetic polyneuropathy ; Perineurium ; Tight junctions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Perineurial cells in the human sural nerve possess tight junctions which in freeze-fracture replicas are seen to be composed of networks of branching and anastomosing P face strands and E face grooves. Isolated circular tight junctions (maculae occludentes) may represent attachment devices between adjacent perineurial lamellae. At the overlapping margins of the cells, a beltlike tight junction (zonula occludens) encircles the cells and is believed to comprise a paracellular diffusion barrier. As the permeability of the perineurium has been found to be altered in diabetic polyneuropathy, the zonulae occludentes have been studied. In freeze-fracture replicas from cases of diabetic polyneuropathy a mixed population of structurally normal and abnormal junctions was observed. In some, the strands were abnormally curved with reduced numbers of intersections, the intervening plasma membrane displaying prominent P face concavities and E face convexities. At other sites, the junctions were severely disorganized and represented by fragmented and isolated strands with few intersections and numerous free ends. These abnormalities resemble changes that have been produced experimentally in epithelial tight junctions by osmotic damage. The possibility is considered that similar mechanisms could result in the alterations of the perineurial tight junctions in diabetic polyneuropathy and account for its impaired permeability barrier properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00305868
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Comparative ultrastructural observations on peripheral nerve abnormalities in the late infantile, juvenile and late onset forms of metachromatic leukodystrophy (1977)
    Springer
    Acta neuropathologica 39 (1977), S. 237-245 
    Details
    ISSN: 1432-0533
    Keywords: Metachromatic leukodystrophy ; Peripheral nerve ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructural findings in nerve biopsies from two cases of late onset metachromatic leukodystrophy were compared with those in cases of late infantile and juvenile onset. Hypertrophic changes and regenerating clusters were more evident in the late onset cases, in which macrophages were less frequent, presumably reflecting the chronicity of the disorder in this form. Inclusions within Schwann cells and endoneurial macrophages were similar in all four cases. Myelin figures, in which the periodicity of major dense lines was 8 nm, were present in Schwann cells associated with myelinated axons. The electron lucent zones between the major dense lines were bisected by lines of lesser electron density. These inclusions were probably related to myelin breakdown. All other inclusions displayed a periodicity of 5.8 nm and consisted of zebra bodies, vacuoles containing irregularly orientated lamellar material and stacks of flattened discs. These inclusions represented the metachromatic sulphatide deposits. Occasional inclusion bodies were observed within axons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00691703
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Peripheral nerve intramembranous particle density and distribution in chronic streptozotocin-induced diabetes in rats (1986)
    Springer
    Acta neuropathologica 72 (1986), S. 62-68 
    Details
    ISSN: 1432-0533
    Keywords: Peripheral nerve ; Experimental diabetes ; Intramembranous particles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Freeze-fracture studies have been made on the sciatic nerve of rats with chronic streptozotocin-induced diabetes mellitus. The density of intramembranous particles was reduced in both the P and E faces of the axolemma of myelinated and unmyelinated axons, in myelin and in the perineurial cells. This may reflect a general reduction in protein synthesis, or excessive protein degradation, related to the diabetic state. The perineurial cells also showed gap junctions which are not normally present in adult rat peripheral nerve. These may represent a reaction to changes in perineurial activity consequent to alterations in the endoneurial tissue fluid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687948
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Relative growth and maturation of axin size and myelin thickness in the tibial nerve of the rat (1990)
    Springer
    Acta neuropathologica 79 (1990), S. 375-386 
    Details
    ISSN: 1432-0533
    Keywords: Peripheral nerve ; Morphometry ; Diabetes mellitus ; Hypomyelination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The relative changes in the growth and maturation of axon size and myelin thickness were studied in the medial plantar division of the tibial nerve in the lower leg and in the motor branches of the tibial nerve to the calf muscles in rats in which diabetes mellitus had been induced with streptozotocin at the time of weaning. Observations were made at 6 weeks and 3, 6, 9 and 12 months of diabetes for comparison with age-matched controls. Similar changes were observed in both nerves. Growth in body weight and skeletal growth was severely retarded from the time of induction of diabetes but at the 6-week stage axon size was not reduced, suggesting that neural growth may initially be relatively protected. At later stages axon size was consistently reduced in the diabetic animals as compared with the controls and showed an absolute reduction at 12 months, as compared with 9 months, that was greater than in the controls. Myelin thickness became reduced earlier and was more severely affected than axon size so that the fibers were relatively hypomyelinated. The myelin changes were greater in larger than in smaller fibers. The index of circularity of axons was reduced in the diabetic nerves. These results show that induction of diabetes in prepubertal rats produces effects on peripheral nerve fibers which differ from those resulting from diabetes induced in adult animals. The effects also differ between large and small nerve fibres. These observations may explain some of the disparate findings obstained in previous studies on experimental diabetes in rats.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00308713
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    Paper (German National Licenses)
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