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  • 1
    Electronic Resource
    Electronic Resource
    A new histo-and cytochemical method for demonstration of cyclic 3′, 5′-nucleotide phosphodiesterase activity in retinal rod photoreceptor cells of the rat (1984)
    Springer
    Histochemistry and cell biology 81 (1984), S. 445-451 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cyclic 3′, 5′-mononucleotide phosphodiesterase (cyclic nucleotide PDEase) activity was studied histo-and cytochemically in the retinal rod photoreceptor cells of the rat by means of a newly developed technique utilizing the intrinsic 5′ nucleotidase activity instead of an exogenous 5′ nucleotidase source (snake venom). Cyclic GMP and cyclic AMP were used as substrates. When cyclic GMP was used as a substrate, the intense activity of phosphodiesterase (PDEase) was distributed over the entire rod outer segments; reaction product was observed on the plasmalemma and on the disk membranes of the outer segments. A slight reaction was also observed on the plasmalemma of the inner segments. However, no precipitate was found in the perinuclear and synaptic regions of the rod photoreceptors. In contrast, when cyclic AMP was utilized as a substrate, a moderate reaction was seen in the synaptic region of the plexiform layer. The intensity of the reaction in the outer segments was much reduced in comparison to the results with cyclic GMP. The enzyme activity was almost completely inhibited by 2 mM 3-isobutyl-1-methylxanthine (IBMX) or 2 mM theophylline, which were potent inhibitors of PDEase. To confirm the propriety of our new cytochemical method, the localization of 5′ nucleotidase was also studied utilizing 5′ AMP or 5′ GMP as substrates. In contrast to the activity of cyclic nucleotide PDEase, the activity of 5′ nucleotidase was distributed on all membranes of the photoreceptors from the synaptic outer plexiform layer to the tip of outer segments. After inhibition of the intrinsic 5′ nucleotidase activity with the use of 1 mM Ni-ions or 10 mM NaF no demonstration of cyclic nucleotide PDEase activity was possible; the existence of intrinsic 5′ nucleotidase activity is necessary for the release of free phosphateions from 5′ AMP (5′ GMP), which are a prerequisite for the histochemical reaction. For comparison, some sections were incubated with the conventional cyclic nucleotide PDEase incubation medium containing snake venom from Ophiophagus hannah. With this conventional method, morphological preservation was extremely poor, and moreover, the reaction itself was weaker than that with the presently described method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00489748
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    The Guillain-Barré syndrome: clinical and electroneuromyographic studies (1984)
    Springer
    Journal of neurology 231 (1984), S. 6-10 
    Details
    ISSN: 1432-1459
    Keywords: Guillain-Barré syndrome ; Nerve conduction velocity ; Prognosis ; Motor paralysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Klinisch-elektrophysiologische Untersuchungen wurden bei 39 Patienten mit Guillain-Barré Syndrom durchgeführt. Es ging um die Frage, welche Elemente in der akuten Phase eine prognostische Beurteilung zulassen. Bei 16 der Patienten, was 52% des Krankengutes entspricht, wurden residuelle Symptome wie motorische Schwäche, fehlende Patellarsehnenreflexe und so weiter nachgewiesen. Das Zurückbleiben von residuellen Symptomen korrelierte mit dem Alter bei Krankheitsbeginn, das Ausmaß der Tetraparese und das Ausmaß der Sensibilitätsstörungen in der akuten Phase. Acht der zehn Patienten, die eine Verminderung der motorischen Nervenleitgeschwindigkeit in einer frühen Krankheitsphase aufwiesen, zeigten später nennenswerte Restsymptome. Tendenzmäßig schienen Restsymptome häufiger bei jenen Patienten zu sein, welche eine Verlangsamung der Leitgeschwindigkeit gemischter Nerven und eine verlängerte Latenz der H-Welle sowie der Residuallatenz aufwiesen. Elektroneurographische Untersuchungen, im besonderen die Bestimmung der motorischen Leitgeschwindigkeit, erlauben zuverlässige Rückschlüsse auf die Prognose dieses Krankheitsbildes.
    Notes: Summary Clinical and electrophysiological studies were carried out on 39 patients with the Guillain-Barré syndrome to evaluate which elements were of prognostic value during the acute phase. Residual clinical signs such as motor weakness and absent patellar tendon reflexes were found in 16 (52%) of those patients who had had a preceding illness. Persistence of deficit was significantly correlated to age at onset, the degree of quadriparesis and loss of deep sensation in the acute phase. Of the 10 patients who showed a reduction in motor nerve conduction velocity (MCV) in the early stage, 8 (80%) revealed significantly residual clinical symptoms at follow-up. There was a tendency for the incidence of residual signs to be more common in the patients with slowing of mixed nerve conduction velocity, and prolonged latency of H-wave and the residual latency. Nerve conduction studies, especially measurement of MCV, were of value as a reliable prognostic indicator in this syndrome.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00313644
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  • 3
    Electronic Resource
    Electronic Resource
    Ultracytochemical study of Ca++-ATPase and K+-NPPase activities in retinal photoreceptors of the guinea pig (1984)
    Springer
    Cell & tissue research 237 (1984), S. 479-489 
    Details
    ISSN: 1432-0878
    Keywords: Ca++-ATPase ; K+-NPPase ; Na+-K+ATPase ; Ultracytochemistry ; Photoreceptor cells, retinal ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ca++-ATPase activity was demonstrated histochemically at light- and electron-microscopic levels in inner and outer segments of retinal photoreceptor cells of the guinea pig with the use of a newly developed one-step lead-citrate method (Ando et al. 1981). The localization of ouabain-sensitive, K+-dependent p-nitrophenylphosphatase (K+-NPPase) activity, which represents the second dephosphorylative step of the Na+-K+-ATPase system, was studied by use of the one-step method newly adapted for ultracytochemistry (Mayahara et al. 1980). In retinal photoreceptor cells fixed for 15 min in 2% paraformaldehyde the electron-dense Ca++-ATPase reaction product accumulated significantly on the inner membranes of the mitochondria but not on the plasmalemma or other cytoplasmic elements of the inner segments. The membranes of the outer segments remained unstained except the membrane arrays in close apposition to the retinal pigment epithelium. The cytochemical reaction was Ca++- and substrate-dependent and showed sensitivity to oligomycin. When Mg++-ions were used instead of Ca++-ions, a distinct reaction was also found on mitochondrial inner membranes. In contrast to the localization of the Ca++ -ATPase activity, the K+-NPPase activity was demonstrated only on the plasmalemma of the inner segments, but not on the mitochondria, other cytoplasmic elements or the outer segment membranes. This reaction was almost completely abolished by ouabain or by elimination of K+ from the incubation medium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228432
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  • 4
    Electronic Resource
    Electronic Resource
    Ultracytochemical localization of Ca++-ATPase activity in pituicytes of the neurohypophysis of the guinea pig (1984)
    Springer
    Cell & tissue research 237 (1984), S. 491-497 
    Details
    ISSN: 1432-0878
    Keywords: CA++-ATPase ; Pituitary gland, pars nervosa ; Pituicytes ; Neurosecretion ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ca++-ATPase activity (cf. Ando et al. 1981) was examined both light- and electron-microscopically in the neurohypophysis of the guinea pig. Apart from a strong activity within the walls of the blood vessels, in the parenchyma of the neurohypophysis the reaction product of the Ca++-ATPase activity was restricted to the plasmalemma of the pituicytes. This reaction was completely dependent upon Ca++ and the substrate, ATP; the reaction was inhibited by 0.1 mM quercetin, an inhibitor of Ca++-ATPase. A reduction of the enzyme activity occurred by 1) adding Mg++ to the standard incubation medium, and 2) substituting Ca++ with Mg++ at varing concentrations. In all experiments the neurosecretory fibers were devoid of Ca++-ATPase activity. The function of the Ca++-ATPase activity in the plasmalemma of the pituicytes is discussed in connection with the regulation of the extracellular Ca++ concentration, which seems to be important with respect to the discharge of secretory material from the neurosecretory fibers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228433
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    Paper (German National Licenses)
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