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  • 1995-1999  (3)
  • 1990-1994  (1)
  • 1880-1889
  • Arabidopsis  (2)
  • Scopolamine  (2)
Materialart
Erscheinungszeitraum
  • 1995-1999  (3)
  • 1990-1994  (1)
  • 1880-1889
Jahr
  • 1
    ISSN: 1432-1106
    Schlagwort(e): Key words Grasping ; Friction ; Sweat ; Scopolamine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The aim of this study was to determine whether relatively long-term changes in skin friction induced by a pharmacological blockade of sweat excretion would alter the grip forces applied to objects of a variety of different surface textures and frictions. Five men and three women were asked to lift the vertically mounted armature of a linear motor between the thumb and index finger and to hold it against an opposing force for 2 s. A 1.0-kHz tone indicated to the subject that the manipulandum had been correctly positioned between the upper and lower position limits. The linear motor generated a 2.5-N force tangential to the skin surface simulating an object weighing approximately 250 g. Three different polyamide plastic surfaces (either smooth or etched with 1.0 mm high Braille beads evenly spaced at 2- or 3-mm intervals) contacted the fingers in these experiments. Subjects lifted and held in a precision grip one of the three surfaces for blocks of ten consecutive trials, but the order of presentation of the three different textures was varied to offset the effect of expectancy. On a second block of ten trials the subjects were requested to release the object slowly to measure the ratio of the grip force normal to the grasped surface to the tangential load force at the moment of slip. This ratio or its inverse provided the coefficient of friction or the slip ratio for a particular subject and surface condition. Twelve hours prior to a second recording session all subjects placed transdermal patches of 1.5 mg scopolamine behind each ear to reduce palmar sweating by blocking the muscarinic receptors of exocrine sweat glands. The subjects were re-tested following procedures that were identical to the first session. Scopolamine significantly reduced the friction of the skin on the smooth and 2-mm beaded surfaces, but the friction of the 3-mm beaded texture was unaffected. Scopolamine also caused subjects to increase both the peak and static grip forces for all the textures including the 3-mm beaded surface, suggesting that for two of the three surfaces they were responding to the increased slipperiness of the skin due to reduced sweat production.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Psychopharmacology 102 (1990), S. 535-543 
    ISSN: 1432-2072
    Schlagwort(e): Alzheimer's disease ; Aging ; Scopolamine ; Transient visual evoked potentials
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Transient visual evoked potentials elicited by the onset of a patterned stimulus were recorded in patients suffering from Alzheimer's disease (AD), in healthy elderly controls and in healthy young individual. The latencies and amplitudes of both the components studied were adversely affected by normal aging and one of the components, CI, but not the other, CII, showed further deterioration in AD. These changes occurred over a range of stimulus contrast levels. The changes found in AD, but not those seen in normal aging, could be mimicked by administration of the cholinergic antagonist scopolamine to young volunteers.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Plant growth regulation 18 (1996), S. 71-77 
    ISSN: 1573-5087
    Schlagwort(e): Arabidopsis ; ethylene ; ethylene binding protein ; signal transduction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A review of work carried out on ethylene binding in higher plants is presented. The use of radio-labelled displacement assays has identified specific 14C-ethylene binding in all tissues so far studied. virtually all higher plants studied contain at least two classes of ethylene binding site, one of which fully associates and dissociates in about 2 h and a class of sites that takes up to 20 h to become fully saturated. Although the types of site differ in their rate constants of association they have similar and high affinities for ethylene. A series of Arabidopsis thaliana mutants shown to vary in sensitivity to ethylene have been analysed for 14C-ethylene binding. One mutant, eti 5, which was shown to be unaffected by ethylene concentrations of up to 10,000 μL L−1 was also shown to exhibit reduced binding. In vivo and in vitro studies on pea have shown that ethylene binding can be detected in this tissue. In vitro studies have shown that both membrane and cytosolic fractions contain measurable amounts of ethylene binding. Interestingly, cytosolic ethylene binding consisted only of the fast associating/dissociating type. Developing cotyledons of Phaseolus vulgaris contain a higher concentration of ethylene binding sites that other tissues and only contain the slow dissociating component. These facets have allowed the purification of ethylene binding protein(s) (EBP) from this tissue. The proteins which bind ethylene can be resolved into two bands of 26 and 28 kDa on semi-denaturing PAGE and the proteins appear to be single entities on a 2-D gels. Data will be presented which indicate a possible role for heterotrimetric G-proteins in the early stages of the ethylene signal transduction pathway.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    ISSN: 1573-5087
    Schlagwort(e): Arabidopsis ; EBP ; ethylene ; phosphorylation ; receptors ; signal transduction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Previous work in our laboratory has demonstrated the existence of high affinity binding sites for the plant growth regulator ethylene. The ethylene binding protein (EBP), from Phaseolus cotyledons, shows many of the characteristics of a functional receptor for ethylene, has been purified on SDS-PAGE and polyclonal antibodies raised in rabbits. Current work involves the investigation of the ethylene transduction signal in a number of ethylene-responsive tissues. In peas, it has been shown that ethylene promotes the phosphorylation of specific proteins of similar molecular weight to the EBP from Phaseolus. Such ethylene-induced phosphorylation can be inhibited by the ethylene antagonist, 2,5-NBD. The antibodies raised to the EBP from Phaseolus have been shown to immunoprecipitate 32P-labelled proteins from membrane protein preparations obtained from pea tissue. Studies on ethylene binding in pea have also shown that the binding of ethylene may be regulated by phosphorylation. Thus, under conditions which promote phosphorylation, binding is inhibited, whereas the reverse is true under conditions which enhance dephosphorylation. Further work is described which examines the effect of protein kinase, protein phosphatase and calcium channel inhibitors on ethylene-induced phosphorylation in peas, together with wild-type (WT) and ethylene insensitive (eti) mutants of Arabidopsis thaliana. The effects of these treatments can be monitored in vivo using the ethylene-induced triple response as a screen. Furthermore, the protein profiles of such treated seedlings can then be compared by labelling protein extracts with 32P and subjecting the samples to SDS-PAGE followed by autoradiography.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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