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  • Evoked potentials  (1)
  • Phase I clinical trial  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 5 (1968), S. 45-54 
    ISSN: 1432-1106
    Keywords: Evoked potentials ; Orienting-reactions ; Readiness potentials ; Expectancy waves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 1. Hirnpotentiale bei unerwarteten Signalen zeigen das Auftreten eines späten Wellenkomplexes mit Spitzenlatenzen von 250—350 msec und relativ großen Amplituden (maximal 15—30 μV). Dieser als „Orientierungspotential” aufgefaßte Wellenkomplex ist besonders verstärkt, wenn auf das unerwartete Signal reagiert werden muß, er kann aber auch ganz ohne motorische Reaktion auftreten. 2. Orientierungspotentiale können sowohl bei zeitlicher Verschiebung des Erwartungszeitpunktes, als auch bei Fehlerwartungen hinsichtlich der Sinnesmodalität beobachtet werden. 3. Wenn die Abweichung vom Zeitmodell der Reize größer ist, so ist die Amplitude des Orientierungspotentials ebenfalls größer. 4. Durch Reaktion auf den nächsten regulären Reiz, der dem Zwischenreiz folgt, konnten längerdauernde Bereitschafts- und Erwartungspotentiale ausgelöst werden. Auch hier konnte vorher ein Wellenkomplex, welcher dem Orientierungspotential entspricht, abgegrenzt werden. 5. Die Positivierung der langsam ansteigenden negativen Bereitschafts- und Erwartungspotentiale beginnt in dieser Anordnung deutlich vor der motorischen Reaktion, also zum Entscheidungszeitpunkt.
    Notes: Summary Brain potentials evoked by unexpected stimuli show a late wave-complex with peak latencies of 250–350 msec and relative large amplitudes (maximal 15–30 μV). This “orienting potential” is especially prominent in cases in which a motor reaction to the unexpected stimulus has to be performed. But it may be seen in some control cases without any overt movement. Orienting potentials are evoked as well by unexpected changes of the occurrence of stimuli in time as by unexpected changes of sense modalities. If the deviation of the time-model of the stimuli is larger, the amplitude of the orienting potential is larger too. If a reaction has to be performed to the next regular stimulus, following the unexpected stimulus, longer lasting readiness- and expectancy potentials between the two stimuli can be evoked. Even in such cases one may see an orienting potential, following the unexpected stimulus. The slowly rising negative readiness- and expectancy potentials start in such an experimental design to become positive not at the moment of motor reaction, but much earlier at the “decision point”.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1041
    Keywords: Phase I clinical trial ; complex protocol ; tolerance ; pharmacokinetics ; praziquantel ; anthelmintic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The tolerance of Praziquantel (2-cyclohexylcarbonyl-1, 3, 4, 6, 7, 11b-hexahydro-2H-pyrazino-[2, 1-a]isoquinoline-4-one) in oral doses of 1×20 mg/kg, 1×50 mg/kg, 3×10 mg/kg and 3×25 mg/kg body weight (τ=4 h) was tested in a complex study involving 36 healthy volunteers. In addition to the usual assessment of clinical chemistry, haematology, coagulation physiology, urinalysis, clinico-physiological examination including EEG, and medical examination, clinico-psychological parameters were also recorded and special neurological investigations were performed. No clinically relevant changes were found in any of the laboratory parameters, nor in the medical-neurological or clinico-physiological examinations. Based on a few clinicopsychological parameters and subjective comments, the largest daily dose tested (3×25 mg/kg=75 mg/kg) produced a slight, transient disturbance in general well-being, which was barely detectable on objective clinical examination. The pharmacokinetic behaviour was dominated by rapid metabolism and pronounced first-pass metabolism of praziquantel, which greatly limits the value of results obtained by GC analysis of unchanged drug in serum. The peak concentration in serum was reached after 1– h, and the elimination half-life for the period 2–8 h was 1–1.5 h.
    Type of Medium: Electronic Resource
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