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  • 1
    ISSN: 1432-0584
    Keywords: LeukÄmie ; Erythrozyten-Membran ; ESR ; Atomabsorption ; AscorbinsÄure ; Leukemia ; Erythrocyte ghosts ; ESR ; Atomic absorption ; Ascorbic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The effect of ascorbic acid on white ghosts of erythrocytes and plasma has been investigated by means of ESR spectroscopy. Since the spectra obtained are identical to the one obtained with leukemic blood, it is concluded that the receptor for vitamin C has to be searched for in membrane and plasma as well. Determination of Cu and Fe by means of atomic absorption spectroscopy revealed that both of the metals are also present in the membrane. In the case of copper, it must exist there as a protein which has not been identified yet. Oxidizing substances, such as KMnO4, reverse the effect produced by ascorbic acid.
    Notes: Zusammenfassung Die Wirkung von AscorbinsÄure auf Erythrozyten-Membran (white ghosts) und Plasma ist mittels der ESR-Spektroskopie untersucht worden. Da die erhaltenen Spektren identisch mit denen sind, die von leukÄmischem Blut erhalten wurden, wird angenommen, da\ der Rezeptor für Vitamin C sowohl in der Membran als auch im Plasma vorhanden sein mu\. Cu- und Fe-Bestimmungen mittels der Atomabsorptionsspektroskopie ergaben, da\ beide Metalle auch in der Membran vorhanden sind. Im Falle des Kupfers mu\ es dort als ein Protein vorliegen, das noch nicht identifiziert wurde. Oxidierende Substanzen, wie z. B. KMnO4, bewirken eine Umkehr des durch die AscorbinsÄure erzeugten Effektes.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0584
    Keywords: ESR ; LeukÄmie ; AscorbinsÄure ; Antioxidanzien ; oxidierende Substanzen ; ESR ; Leukemia ; Ascorbic acid ; Antioxidants ; Oxidizing agents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Addition of ascorbic acid to native blood or to erythrocytes and leukocytes of healthy persons results in an ESR spectrum which is identical to the one obtained with blood or its fractions of leukemic patients. After an initial increase the spin concentration decreases at higher (〉 100 mM) concentrations of ascorbic acid. These findings confirm observations made thus far that cancerous tissue, finally, exhibits a lower spin concentration and a higher concentration of antioxidants than its corresponding healthy tissue. Application of oxidizing substances, such as KMnO4 or CuCl2, to erythrocytes either before or after administration of vitamin C compensates the effect of the latter substance depending, of course, on the concentration used. The effect produced by ascorbic acid on blood and its fractions seems to be unique since neither vitamin E or vitamin A or catechol and its amines noradrenaline, adrenaline, dopamine, and its precursor amino acid dopa, cytochrome c, FMN, NADH, Na2S2O4, ethylenglycol, glyceraldehyde, or tyrosine produce this effect. Ascorbic acid seems to play, thus, an important role in the balance of health and disease, as has been pointed out by Szent-Györgyi [16]. Its possible receptor(s) and its implication in the formation of cancer, or at least leukemia, will be discussed in detail elsewhere [9].
    Notes: Zusammenfassung Eine Zugabe von AscorbinsÄure zu nativem Blut oder zu Erythrozyten und Leukozyten von gesunden Personen ergibt ein ESR-Spektrum, das identisch zu dem ist, welches mit Blut oder seinen Fraktionen von LeukÄmie-Patienten erhalten wird. Nach einer anfÄnglichen Zunahme nimmt die Spin-Konzentration bei höheren (〉 100mM) AscorbinsÄure-Konzentrationen wieder ab. Diese Ergebnisse bestÄtigen bisherige Beobachtungen, wonach Krebsgewebe im fortgeschrittenen Stadium eine niedrigere Spin-Konzentration und eine grö\ere Konzentration an Antioxidanzien als das dazugehörige gesunde Gewebe besitzt. Eine Zugabe von oxidierenden Substanzen, wie z. B. KMnO4 oder CuCl2, zu Erythrozyten entweder vor oder nach Vitamin C Zugabe kompensiert den Effekt der letzteren Substanz, was natürlich von der gebrauchten Konzentration abhÄngt. Der durch AscorbinsÄure an Blut und seinen Fraktionen erzeugte Effekt scheint spezifisch zu sein, da weder Vitamin E nach Vitamin A oder Catechol und seine Amine Noradrenalin, Adrenalin, Dopamin und sein VorlÄufer, die AminosÄure Dopa, Cytochrom c, FMN, NADH, Na2S2O4, Äthylenglykol, Glyzeraldehyd oder Tyrosin diesen Effekt erzeugen.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 21 (1974), S. 113-124 
    ISSN: 1432-1106
    Keywords: Decerebrate rigidity ; Renshaw cell activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of pre- and/or intercollicular decerebration on the activity and responsiveness of individual Renshaw cells were studied in 15 adult cats under continuous light anesthesia. It was found that decerebration either had no effect on the spontaneous activity of Renshaw cells and their response to antidromic stimulation, or it enhanced activity, provided that the blood pressure was prevented from falling below critical values. Spontaneous activity showed the more pronounced increase, particularly after intercollicular decerebration. Severing of the ipsilateral dorsal roots had no noticeable effect on the Renshaw cell behaviour. Concomitant with the release of extensor a-motoneurones following decerebration — as indicated by an augmentation in the amplitude of monosynaptic reflexes — the Renshaw cell response to orthodromic stimulation was enhanced. The phasic response of Renshaw cells, elicited by muscular ramp stretch, was also more pronounced after decerebration. Thus judging by the experimental results obtained in anesthetized animals, any decrease in Renshaw cell activity would not seem to be a primary cause of decerebrate rigidity.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Pflügers Archiv 372 (1977), S. 131-138 
    ISSN: 1432-2013
    Keywords: Primary muscle spindle endings ; Decerebrate rigidity ; Correlations in the Ia multi-channel system ; Spinal reflex loop
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The influence of extrafusal muscle activity in anaemically decerebrate cats upon discharge patterns of primary spindle endings was ascertained by simultaneously recording spike trains from several Ia afferents and muscle tension fluctuations of the triceps-surae muscle. 1. Tension fluctuations were averaged with respect to spikes from primary endings yielding tension “trajectories” of specific shape for each spindle and probably reflecting frequently recurring mechanical events in the spindles' surroundings. 2. Spindles situated in close vicinity and influenced by similar mechanical events as evidenced by similar average tension trajectories are correlated in their discharge patterns to a degree depending on the strength of their mechanical coupling. 3. The modulation of spindle discharge frequency in response to average tension changes at the muscle tendon is very different in amplitude for different spindles; this response may show a high sensitivity. It is usually phase advanced by 90–180° with respect to the “internal length” changes; between spindles there may be phase differences of up to 180°. 4. It is concluded that primary endings react very sensitively to local extrafusal events. The CNS receives much more accurate information about these events in the correlation of several Ia afferents than in the discharge of a single fibre.
    Type of Medium: Electronic Resource
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