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  • Electron microscopy  (4)
  • Thalidomide  (3)
  • 1
    ISSN: 1432-0533
    Keywords: Thalidomide ; Wallerian degeneration ; Schwann cell proliferation ; Immune inhibition ; Endoneurial edema
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In addition to the well-known teratogenic effect of thalidomide, previous studies have revealed mild immunosuppressive properties and, more recently, and antiangiogenic activity. To find out more about the specificity of these effects we studied the influence of orally administered thalidomide on Wallerian degeneration in rats. Wallerian degeneration is a potent experimental model for studying reproducible cell proliferation in vivo. Examination of distal nerve segments of transected sciatic nerves from rats that had been treated with thalidomide (2×250 mg/kg per day) revealed a significant reduction of endoneurial cell counts at 10–15 days after surgery compared to that seen in controls. This effect was not statistically significant, at a very early stage of Wallerian degeneration, i.e., at 5 days after transection of the nerve. Subperineurial edema and phagocytosis was also reduced, although this was not statistically significant. This apparently nonspecific inhibitory effect of thalidomide during early Wallerian degeneration shown in the present study should be investigated further for its possible relationship to other previously established inhibitory activities of thalidomide, especially its immunosuppressive effect in man.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 99 (2000), S. 39-47 
    ISSN: 1432-0533
    Keywords: Key words Sural nerve ; Muscle fiber diameter ; Morphometry ; Electron microscopy ; Myotonic ¶dystrophy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We compared peripheral nerve fibers and muscle fibers in myotonic dystrophy (MD) using a computer-assisted device for morphometry. In the 17 cases with MD studied, the sural nerves of 14 cases (82%) showed various degrees of reduction of the myelin sheath area (MSA) per endoneurial area. Of these, 8 cases (47%) presented with a mild reduction of the MSA, 5 cases (29.4%) with moderate reduction, and one case (6%) with severe reduction. The number of myelinated nerve fibers was not significantly reduced in MD when compared with control nerves, due to clusters of small regenerated nerve fibers. The mean diameter of the muscle fibers in 6 of the 17 cases was less than 40 μm. Of these 6 severely affected cases, ¶5 revealed a considerable reduction of the MSA. Other cases, which appeared to be normal in respect to the diameter of muscle fibers, showed various degrees of reduction of the MSA. Thus, there is usually, but not always a morphometric correlation of the severity of changes between peripheral nerves and muscle. The severity of the peripheral neuropathy appears to depend largely on the patient’s age, the stage of the disorder, and the time of progression. Electron microscopic examination of sural nerves showed significant, though non-specific pathological changes.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 10 (1968), S. 218-241 
    ISSN: 1432-0533
    Keywords: Myotonic dystrophy ; Sarcoplasmic masses ; Striated annulets (Ringbinden) ; Muscle fiber ; Electron microscopy ; Phase microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Das Biopsiematerial von drei Patienten mit unterschiedlichen klinischen und pathologischen Stadien der myotonischen Dystrophie wurde phasenkontrast-und elektronenmikroskopisch untersucht. Beim 1. und 2. Fall waren “sarkoplasmatische Massen” und “Ringbinden” besonders zahlreich, während sie beim 3. Fall mit klinisch erheblich fortgeschrittener Muskelatrophie nur ausnahmsweise vorkamen. Elektronenmikroskopisch erschienen fast alle Elemente der Muskelfasern, zumindest an einigen Stellen, von dem atrophischen oder dystrophischen Prozeß betroffen: Myofilamente, Z-Streifen, Triaden, Kerne, Mitochondrien und Sarkolemm. Außerdem fanden sich cytoplasmatische Cysten, multilamellierte Körperchen, zahlreiche Lipofuscingranula und verschiedene andere abnorme Strukturen. Besonders kennzeichnend für die Erkrankung waren die “sarkoplasmatischen Massen”, die mit variablen Mengen von fehlorientierten Myofilamenten, aber auch von anderen Komponenten der Muskelzelle ausgefüllt waren. Die Ringbinden wurden von fehlorientierten Myofibrillen gebildet, indem sie meist kreisförmig die im Zentrum normal ausgerichteten Myofibrillen umschlossen. Einzelne Veränderungen, die bisher weder bei der myotonischen Dystrophie noch in irgendeiner anderen Muskelkrankheit nachgewiesen worden sind, konnten in leicht dystrophischen wie auch in hochgradig atrophischen Fasern nachgewiesen und identifiziert werden: Große homogene Lacunen, die sich vom sarkoplasmatischen Reticulum herleiten und eigenartige geometrische Anordnungen der terminalen Cisternen. Der Ursprung bestimmter anderer Strukturen blieb unklar. In unserem Material fanden sich keine segmentalen Nekrosen, so daß sich die Relation des dystrophischen Prozesses zur Zenkerschen Degeneration und zur Atrophie, den nach histologischen Untersuchungen wesentlichsten Befunden bei der Steinertschen Erkrankung, nicht eindeutig bestimmen ließ.
    Notes: Summary Biopsies from three patients with different clinical and pathological stages of myotonic dystrophy were studied by phase and electron microscopy. Large sarcoplasmic masses and spiral annulets were prominent in Cases 1 and 2 while in Case 3, featured clinically by atrophic weakness, they were infrequent. In the latter the residual fibers were either large and dystrophic or small and atrophic. Electron microscopically, nearly all components of the muscle cell, in places, were involved in the dystrophic or atrophic process, such as myofilaments, Z discs, triads, nucleic, mitochondria, and the sarcolemma. In addition, cytoplasmic cysts, multilammellated bodies, and lipofuscin granules were observed. The most characteristic feature of the disease were sarcoplasmic masses, filled with varying amounts of disoriented myofilaments and other sarcoplasmic components. Disoriented myofibrils often encircled the remaining core of normal myofibrils, thus forming the striated annulets (Ringbinden). Several other abnormalities, not previously reported in myotonic dystrophy or any other myopathy, were identified in slightly dystrophic as well as in severaly atrophic fibers. These were large, homogenous lacunes derived from the sarcoplasmic reticulum and peculiar geometric arrangements of terminal cisternae. The origin of some other structures remains obscure. The relation of the dystrophic process to segmental degeneration and atrophy, the principal histologic findings in Steinert's disease, is unsettled since segmental necrosis was not observed in our samples for phase and electron microscopy.
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  • 4
    ISSN: 1432-0533
    Keywords: Unmyelinated axons ; Sensory neuropathy ; Thalidomide ; Aging ; Senile peripheral nerves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Sural nerve biopsies of four patients, aged 54–76 years, with a predominantly sensory type of neuropathy following high dosages of thalidomide were examined by light and electron microscopy. The present study includes a qualitative and quantitative evaluation of unmyelinated nerve fibers. Despite severe neuropathy, increased numbers of small unmyelinated axons per endoncurial area were noted in all patients. This numerical increase appeared to be independent of aging, since it was not seen in two senile controls, studied at the age of 83 and 88 years. The increase in the endoneurial density of unmyelinated axons, especially of small sized fibers, is likely to be related to regeneration following degeneration of unmyelinated axons although endoneurial shrinkage secondary to loss of large myelinated fibers could have caused an additional increase in the number of axons per endoneurial area. Axonal sprouting, despite degeneration of large numbers of myelinated and unmyelinated fibers, appears to be consistent with some of the characteristic clinical features of thalidomide neuropathy such as paresthesias, hyperesthesia for pain and temperature, and disturbances of autonomic functions. On the other hand, a variable number of empty Schwann cells (bands of Büngner) and pockets at the surface of many Schwann cells noted in the four patients with neuropathy were also seen in both senile controls with no signs of neuropathy. Thus, it is obvious that pockets and empty Schwann cells may be related to aging or other causes of slow axonal wasting with Schwann cell proliferation and are not necessarily associated with clinically manifest neuropathy.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 65 (1985), S. 285-292 
    ISSN: 1432-0533
    Keywords: Thalidomide ; Neuropathy ; Conduction velocity ; Myelin sheath
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Morphological studies of experimental thalidomide neuropathy have thus far failed to show any significant structural changes. The present investigation was performed on sural nerves of female New Zealand white rabbits showing a reduction of sensory conduction velocity after oral treatment with thalidomide (100 mg/kg b.wt. per day) for a period of 33 weeks. Rabbits of the same strain and equal sex, weight, and number served as controls. Very few nerve fibers were undergoing Wallerian degeneration in both groups, experimental animals and controls. Morphometry, however, revealed a statistically significant reduction of the mean myelin thickness of sural nerve fibers in the thalidomide group of rabbits as compared to controls. The mean myelin thickness of the largest nerve fibers was also significantly smaller than in the control group. On the other hand, axonal diameters were not significantly altered. The association between the decrease of the sensory conduction velocity, the reduction of the myelin sheath thickness, and the chronic thalidomide application is discussed.
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  • 6
    ISSN: 1432-1459
    Keywords: Ethylene oxide ; Peripheral neuropathy ; Morphometry ; Electron microscopy ; Demyelination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case is reported of ethylene oxide polyneuropathy after 5 months of exposure. There was symmetrical distal weakness of both lower extremities and transitory reduced nerve conduction velocities with increased latencies. Sural nerve biopsy revealed nerve fibre degeneration of the Wallerian type, associated with reduction of axonal cross-sectional areas and some degree of nerve fibre regeneration that could be confirmed morphometrically. In addition, there was conspicuous paranodal vesicular disintegration of individual myelin lamellae. Unusual cisternae with introverted hemidesmosomes were noted in endoneurial fibroblasts.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 128 (1972), S. 393-405 
    ISSN: 1432-0878
    Keywords: Peripheral nerve ; Polyamines ; Autoradiography ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Mit Hilfe der Autoradiographie von Semi- und Ultradünnschnitten wurde die Verteilung der Radioaktivität nach Applikation von 3H-Putrescin im intakten und im degenerierenden N. ischiadicus der Ratte sowie in Spinalganglien untersucht. Im intakten und im geschädigten Nerven war die Radioaktivität, die zum weit überwiegenden Anteil als Spermidin und Putrescin vorkam, in allen zellulären Bestandteilen des Nerven, im Cytoplasma, in den Kernen und sehr deutlich auch in den Markscheiden, lokalisiert. Im extrazellulären Raum und über den Kollagenfibrillen war demgegenüber nur eine sehr geringe Radioaktivität festzustellen. Die physiologische Funktion von Spermidin und Putrescin im Myelin und den anderen Zellbestandteilen wird in erster Linie im Zusammenhang mit der in diesen Strukturen ebenfalls lokalisierten RNA diskutiert, da zahlreiche Hinweise für eine Rolle der Polyamine in der RNA- und Proteinsynthese vorliegen.
    Notes: Summary The distribution of radioactivity from 3H-putrescine was studied in intact and degenerated sciatic nerves, and spinal ganglia of rats by means of high resolution autoradiography. During the first three days after the administration of the labeled putrescine, the main proportion of radioactive material in the nerves was represented by spermidine and putrescine. Both, in intact and degenerating nerves, developed silver grains were deposited in all cellular components of the nervous tissue, the myelin sheath being markedly tagged. Perineural tissue was also labeled considerably, however, there was no significant amount of label in the extracellular space and in the collagen fibrils. The possible physiological significance of putrescine and spermidine in myelin and in other cellular components of nerves is discussed.
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