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  • 1970-1974  (3)
  • Node of Ranvier  (2)
  • Cerebral amyloidosis  (1)
  • Ethanol
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of neurology 206 (1973), S. 39-59 
    ISSN: 1432-1459
    Keywords: Congophilic angiopathy ; Cerebral amyloidosis ; Atypical Alzheimer's disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung An Hand von 5 Fällen einer kongophilen Angiopathie (3 Männer im Alter von 58, 58 und 66 Jahren, 2 Frauen im Alter von 52 und 74 Jahren) wird zur Nosologie und Ätiologie der Erkrankung Stellung genommen. Die klinische Symptomatologie war uneinheitlich. Sie entsprach in 1 Fall einem Morbus Alzheimer, in 1 weiteren Fall einem „atypischen Alzheimer“, in 2 Fällen standen Symptome vasculärer Genese im Vordergrund, in 1 Fall mit „Wurzelreizsyndrom“ und Tod durch Lungenembolie bestanden weder neurologisch noch psychisch irgendwelche Auffälligkeiten. Histopathologisch waren zusätzlich zur kongophilen Angiopathie in allen Fällen senile Plaques gegeben. Alzheimersche Fibrillenveränderungen konnten nur in den 2 Fällen mit Alzheimer-Symptomatik nachgewiesen werden. In je 3 Fällen fanden sich zusätzlich kreislaufbedingte Schäden in Form fokaler Nervenzellverödungen der Rinde sowie in Form von Massenblutungen in verschiedenen Großhirnlappen. Bei diesen Blutungen handelte es sich zweimal um frische tödliche Blutungen, in 1 Fall war die Blutung nach operativer Entleerung knapp 1 Jahr überlebt worden. Für eine Hypertonie als Ursache der Blutungen ergaben sich keine Hinweise. Die Regelmäßigkeit des Vorkommens der kongophilen Angiopathie zusammen mit senilen Plaques und die durch elektronenoptische Untersuchungen gesicherte Tatsache der Amyloidnatur beider Prozesse weisen darauf hin, daß es sich bei ihnen um die morphologischen Ausdrucksformen einer cerebralen Amyloidose handelt (bei der kongophilen Angiopathie um deren Gefäßform, bei den senilen Plaques um die Parenchymform). Es liegt damit morphologisch ein eigenständiger Krankheitsprozeß vor. Er ist gegenüber dem Morbus Alzheimer abzugrenzen, dessen kennzeichnendes morphologisches Substrat, die Alzheimerschen Fibrillenveränderungen, nach elektronenoptischen Untersuchungen nicht mit Amyloid identisch sind. Da die cerebrale Amyloidose in ursächlicher Hinsicht vorrangig als Altersamyloidose anzusehen ist, wird angenommen, daß Alternskrankheiten wie der präsenile Alternsprozeß des Morbus Alzheimer die Entstehung einer cerebralen Amyloidose entscheidend begünstigen. Die häufige Kombination der Erkrankung mit klinischen und histopathologischen Symptomen des Morbus Alzheimer dürfte sich am ehesten durch diese ursächlichen Beziehungen erklären lassen. Die cerebrale Amyloidose kann aber nicht ausschließlich als Altersamyloidose angesehen werden. Es ist derzeit noch ungeklärt, welche anderen Faktoren eine Rolle bei der Entstehung der Erkrankung spielen können. Die ursächliche Bedeutung von Erkrankungen des rheumatischen Formenkreises und erblicher Faktoren wird diskutiert.
    Notes: Summary The nosology and etiology of angiopathy are considered with reference to five cases (3 men aged 58, 58, and 66 and 2 women aged 52 and 74). The clinical symptomatology was not uniform. In one case it was similar to that of Alzheimer's disease, while in another it was similar to that of “atypical Alzheimer's disease”; in two cases vascular symptoms were predominant. One patient with a radicular syndrome died of a pulmonary embolism; neither neurological nor psychological examination revealed any unusual features. Histopathological study revealed senile plaques as well as the congophilic angiopathy. Neurofibrillar tangles were seen only in the two cases with symptom complexes reminiscent of Alzheimer's disease. In three cases there was vascular damage in the form of focal erosion of nerve cells in the cortex and massive hemorrhage in various cerebral lobes. In two cases the hemorrhage was fresh and proved fatal while the other patient survived for just one year after surgical evacuation. There was no evidence for hypertonia as the cause of hemorrhage. The regular occurrence of congophilic angiopathy together with senile plaques and the amyloid nature of both processes (demonstrated by means of electron microscopy) indicate that each of the two conditions is a morphological form of cerebral amyloidosis (the vascular form in cases with congophilic angiopathy and the parenchymal form in cases with senile plaques). Thus, morphologically this is a separate condition which should be differentiated from Alzheimer's disease; examination by electron microscopy reveals that Alzheimer's baskets are not identical with the neurofibrillar changes seen in amyloidosis. As cerebral amyloidosis can be regarded primarily as amyloidosis of old age from the etiological point of view, it is assumed that illnesses due to advancing age, such as Alzheimer's disease, predispose the patient to the development of cerebral amyloidosis. The frequent association of amyloidosis with clinical and histopathologic signs of Alzheimer's disease is most probably due to this causal relationship. Cerebral amyloidosis cannot be regarded exclusively as disease of old age, however. It is still not known what other factors are involved in the illness. The etiological significance of rheumatoid illnesses and genetic factors is discussed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Pflügers Archiv 349 (1974), S. 133-148 
    ISSN: 1432-2013
    Keywords: Node of Ranvier ; Sodium Permeability ; Aconitine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of aconitine (10−5–10−6 g/ml) on membrane potentials and membrane currents of myelinated nerve fibres of Xenopus laevis was investigated. The following observations were made: a) Current clamp conditions: Slow depolarization (10–15 mV), decrease of amplitude and maximum rate of rise of action potential, finally inexcitability. With inward current pulses ‘hyperpolarizing responses’ could be elicited at membrane potentials more negative than the resting potential (E r ). Neither spontaneous activity nor repetitive responses to electrical stimuli were observed. No effects of aconitine were found in Na-free solutions or in the presence of tetrodotoxin. b) Voltage clamp conditions: Development of steady inward current at normal resting potential due to formation of a non-inactivating sodium permeability; heavily poisoned nodes therefore exhibit an N-shaped steady-state current voltage relation with negative slope at membrane potentials more negative thanE r . These non-inactivating sodium channels open more slowly than normal sodium channels, and can only be closed by hyperpolarizing the membrane by about 50 mV. The majority of sodium channels have almost normalτ m; theirm ∞ andh ∞-V relations are shifted by 10–15 mV towardsE r . It is concluded that these changes of the sodium permeability account for the changes of electrical activity observed after treatment with aconitine.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Pflügers Archiv 333 (1972), S. 51-61 
    ISSN: 1432-2013
    Keywords: Node of Ranvier ; Ionic Currents ; Scorpion Venom ; Calcium Ions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Voltage clamp experiments were done on myelinated nerve fibres of Xenopus laevis to study the effect of calcium on the ionic currents of the nodal membrane treated with scorpion venom. Increasing the calcium concentration of the medium from 1.8 to 7.2 mM produced the following changes of the sodium and potassium permeabilities,P Na andP K: a) The incomplete sodium inactivation, which is typical for nodes of Ranvier treated with scorpion venom, is abolished. The curves relatingm ∞ and τ m to membrane potential are shifted by 8–10 mV towards larger depolarizations.P Na and the time constants of the fast and slow components of the sodium inactivation remain practically unchanged. b) The maximum potassium permeability,P K, which is reduced by scorpion venom to 45% of the value observed in the normal node, increases to 68% by addition of calcium ions; τ n is unchanged. These effects of calcium ions on the ionic permeabilities explain the shortening of the extremely prolonged action potential and the inhibition of spontaneous activity observed in nodes of Ranvier poisoned with scorpion venom.
    Type of Medium: Electronic Resource
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