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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Rheologica acta 10 (1971), S. 61-66 
    ISSN: 1435-1528
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Zusammenfassung Steifheit ist ein Problem, das dem Kliniker bekannt ist. Steifheit am Morgen ist ein Hauptgesichtspunkt für die Diagnose von rheumatischer Arthritis und ist ein äußerst wichtiges Merkmal für die Diagnose von Wirbelsäulenversteifungs (“pocker back”). Diese ist ein wichtiges Merkmal in Fällen von Patienten mit Osteoarthrosis, die unter Gelenkschwellung leiden, und die Gelenke daher nach einer Ruheperiode viel steifer sind. Therapeutisch hat sie Bedeutung für das Symptomenbild des Patienten und sie ist ein Maßstab für die Wirksamkeit der Behandlung von rheumatischer Arthritis. Arthrographen wurden angefertigt, um die Steifheit des Metacarpophalangealgelenks des Fingers und des Kniegelenkes zu messen. Tierexperimente haben gezeigt, daß 50% der Gelenksteifheit von passiver Muskelstrek-kung und 50% von Geweben im Gelenk selbst und außerhalb herrühren. Reflexbedingte Muskelaktivität spielt keine Rolle, mit Ausnahme von Fällen mit neuro-muskulären Erkrankungen wieParkinsonismus und Myotonia Congenita. Um ein charakteristisches Spannungs-Dehnungsdiagramm zu erhalten, wird das Gelenk in eine sinusartige Bewegung gebracht. Untersuchungen der Spannungsrelaxation haben einige Hinweise auf die Komponenten der physischen Steifheit gegeben. Zunehmende Steifheit ist physiologisch altersbedingt. Eine Temperaturerhöhung auf 45 °C vermindert die Steifheit um etwa 25%, und eine Temperaturerniedrigung erhöht, im Gegensatz dazu, die Steifheit um etwa denselben Betrag. Erhöhte Steifheit ist pathologisch in Fällen mit rheumatischer Arthritis, Systemsklerose und Osteoarthrose. Das Auftreten von Gelenkschwellungen bei Osteoarthrose ist, wie die Analyse von Überlagerungsdiagrammen andeutet, mehr eine Erscheinung, die von Veränderungen der umhüllenden Gewebe herrührt, als von Veränderungen zwischen den Gelenkflächen. Mit diesem Gerät wurden einige künstliche Schmiermittel geprüft.
    Notes: Summary Stiffness is an important subjective phenomenon diagnostically and therapeutically in rheumatic diseases such as rheumatoid arthritis and osteoarthrosis. A quantitative and qualitative assessment of these phenomena have been made by arthrographs which impose a sinusoidal motion on the metacarpo-phalangeal and knee joints respectively and record the torque in relation to the displacement. The reproducibility with the joint in situ and moved is satisfactory. A hysteresis torque/ displacement plot is obtained with both joints. Reflex muscle activity may be measured at the joint, as in myotonia congenita and Parkinsonism. In patients without neuromuscular disorders electromyographic studies have shown that the muscles are electrically silent during sinusoidal motion and that active contraction distorts the tracing. The latter fact may be useful in the evaluation of patients with psychological factors producing muscle tension, which may be decreased with diazepam. Using the cat's wrist joint it has been shown that the passive stretching of muscles accounts for 41 per cent of the stiffness recorded at the joint and the capsule 47 per cent, a finding in keeping with work on the distal interphalangeal joint of the human finger. Stiffness increases with advancing age and decreased temperature. Conversely, warming the joint reduces its stiffness. Articular gelling in patients with osteoarthrosis may be demonstrated after periods of rest and the results suggest that such changes are due to alterations in the periarticular and muscle tissues. The rapid diminution in torque after rest in one position was not detected in normal joints even after longer periods of immobilisation.
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  • 2
    ISSN: 1432-2048
    Keywords: Actin ; Calmodulin ; Ernodesmis ; Microfilament ; Microtubule ; Tubulin ; Wound healing (alga)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The involvement of calmodulin (CaM) in wound-induced cytoplasmic contractions in E. verticillata was investigated. Indirect immunofluorescence of CaM in intact cells showed a faint, reticulate pattern of fluorescence in the cortical cytoplasm. Diffuse fluorescence was evident deeper within the cytoplasm. In contracted cells, CaM co-localizes with actin in the cortical cytoplasm in extensive, longitudinal bundles of microfilaments (MFs), and in an actin-containing reticulum. No association of CaM with tubulin was ever observed in the cortical cytoplasm at any stage of wound-healing. When contraction rates in wounded cells are measured, a lag period of 2 min is followed by a rapid, steady rate of movement over the subsequent 10 min. The delay in the initiation of longitudinal contraction corresponds to the time necessary for the assembly of the longitudinal MF bundles. Cytoplasmic motility was inhibited in a dose-dependent manner by CaM antagonists. In these inhibited cells, MF bundles did not assemble, or were poorly formed. In the latter case, CaM was always found associated with MFs. These results indicate a direct spatial and temporal correlation between CaM and actin, and a potential role for CaM in regulating the formation of functional MF bundles during wound-induced cytoplasmic contraction in Ernodesmis.
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  • 3
    ISSN: 1432-2048
    Keywords: Actin ; Calmodulin ; Ernodesmis ; Membrane skeleton ; Microfilaments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ultrastructural changes in the cortical cytoskeleton during wound-induced cytoplasmic contraction were examined in the coenocytic green alga Ernodesmis verticillata. Both calmodulin (CaM) and actin were localized in intact and contracting cells by immunogold labeling. Within 5 min after wounding, compact microfilament (MF) bundles were observed which increase in diameter as cytoplasmic contraction proceeds. Calmodulin labeling is associated with amorphous material studding the MF bundles, whereas actin labeling occurs along the individual MFs. No MF bundles were ever observed during contraction that were not also labeled with anti-CaM antibodies. In cells treated with the CaM antagonist W-7 (N-[6-aminohexyl]-5-chloro-1-naphtha-lenesulfonamide), MF bundles do not form, and the formation of loosely arranged MFs (similar to nascent bundles in untreated cells) is greatly retarded. We propose that CaM binds indirectly to actin by activating an actin-binding regulatory protein which functions in early stages of the transduction sequence leading to functional MF bundles. Additionally, ultrastructural evidence is presented for a plasma-membrane skeleton or undercoating in this alga.
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  • 4
    ISSN: 1615-6102
    Keywords: Alga ; Actin ; Calmodulin ; Ernodesmis ; Membrane recycling ; Microfilaments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Changes in the plasma membrane surface and in the cortical cytoplasm during wound healing in giant green algal cells ofErnodesmis verticillata (Kützing) Bφrgesen were followed using scanning and transmission electron microscopy. Microvillus-like structures that contain cytoplasmic and cytoskeletal constituents were observed emanating from the surface of the plasma membrane at the retracting/cut end of wounded cells. These delicate structures seem to be remnants of cell wall-plasmalemma connections that draw out the plasma membrane and cortical components from the contracting cytoplasm as it pulls away from the cell wall. Most of these connections break during wound healing and, when contraction stops, the microvillus-like protrusions become progressively shorter. In cells treated with a calmodulin antagonist (W-7), a number of distinctive bodies accumulate that are of unknown composition, are oblong in shape, and have a diameter slightly smaller than the protoplasmic protrusions. Ultrastructural and other data indicate that these bodies result from retrieved constituents of the plasma-membrane protrusions, as they do not accumulate in unwounded drugtreated cells or in cells treated in W-5. These findings suggest that the protoplasmic protrusions accumulate membrane and cytoplasmic components that are retrieved and recycled during wound healing inErnodesmis by a novel mechanism. The combined plasma membrane surfaces of the microvillus-like protrusions may help to account for the drastic decrease in surface area that occurs during wound healing.
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  • 5
    Publication Date: 1991-12-01
    Print ISSN: 0032-0935
    Electronic ISSN: 1432-2048
    Topics: Biology
    Published by Springer
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  • 6
    Publication Date: 1991-01-01
    Print ISSN: 0032-0935
    Electronic ISSN: 1432-2048
    Topics: Biology
    Published by Springer
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