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  • Functional Asymmetry  (1)
  • High (Atmospheric) Pressure  (1)
  • 1
    ISSN: 1432-0738
    Keywords: Acute CO Intoxication ; Venous Oxygen Pressure ; Blood Sugar Concentration ; High (Atmospheric) Pressure ; Effects of CO ; Akute Kohlenoxidvergiftung ; Venöser Sauerstoffdruck ; Blutzuckerverhalten ; Überdruck ; Spezifische Kohlenoxidwirkungen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung In drei Versuchsreihen an Kaninchen werden nach 1stündiger Einwirkung hoher CO-Konzentrationen unter normalem und erhöhtem Luftdruck Blutzucker, Kohlenoxidhämoglobingehalt (COHb) und Sauerstoff-Partialdruck (pO2) in der V. jugularis gemessen. Hierzu werden analoge Versuche mit reinem Sauerstoffmangel, erzielt durch 1stündige Einwirkung von Sauerstoff-Stickstoffgemischen, in Beziehung gesetzt. Bei 2000 ppm CO in der Einatmungsluft steigt unter normalem atmosphärischen Druck im Mittel von 22 Versuchen der Blutzucker nach 1 Std um 87 % gegenüber dem Ausgangswert von 98,5 mg- % an. Der Sauerstoffdruck im venösen Blut fällt von etwa 45 Torr bereits nach 10 min auf die Hälfte ab und erreicht den Endwert von 9,5 Torr O2 schon nach 30 min. Der sich ebenfalls rasch einstellende COHb-Endwert beträgt 47,9 % im Mittel. Bei Einatmung eines Luftgemisches mit 2000 ppm CO unter einem Druck von 4 ata steigt der Blutzucker trotz annähernd gleichem COHb (43,1 % im Mittel) und etwa gleichem pCO im Gewebe nicht an. Hierbei ist von Bedeutung, daß der venöse pO2 nur auf einen Endwert von 20 Torr absinkt. Die Endwerte für pO2 und COHb sind bereits nach 10 min erreicht. Durch Inhalation eines sauerstoffarmen Stickstoff-Luftgemisches (4 bis 6 Vol- % O2 in der Einatmungsluft) läßt sich der venöse pO2-Abfall der ersten Versuchsreihe mit 2000 ppm CO in Luft unter 1 ata nachahmen. Es zeigt sich, daß pO2 auf etwa 10 Torr absinkt, während der Blutzucker um 100 % gegenüber dem Ausgangswert ansteigt. Nach diesen Untersuchungen scheint der Blutzuckeranstieg bei akuter CO-Vergiftung nicht spezifisch durch den CO-Gehalt von Blut und Geweben, sondern durch den unspezifischen Sauerstoffmangel der Gewebe — als Folge der hypoxischen Wirkung des Kohlenoxids — verursacht zu sein.
    Notes: Abstract In rabbits, exposed to high CO concentration at normal and increased atmospheric pressure for 1 h, we investigated the effects of CO intoxication of the level of blood sugar, on carboxyhemoglobin (COHb) concentration in blood and on the partial pressure of oxygen (pO2) in jugular venous blood. Analogous experiments were performed with rabbits exposed for 1 h to oxygen deficiency produced by breathing a mixture of oxygen and nitrogen. In animals exposed to 2000 ppm CO under normal atmospheric pressure the level of blood sugar increases after 1 h from 98,5 mg- % to 184 mg- % (mean value of 22 experiments). The partial pressure of oxygen in venous blood decreases within 10 min from 45 torr to about 23 torr and reaches a final value of 9,5 torr O2 after 30 min. The final value of COHb (mean value 47,5 %) is also reached within a short time. Breathing 2000 ppm CO under 4 ata the blood sugar concentration does not increase in spite of about the same CO Hb concentration (mean value 43,1 %) and similar pCO values at the same time. The venous pO2 decreases only to a final value of 20 torr. The final values of pO2 and CO Hb are reached within only 10 min. Breathing mixture of nitrogen and air (4 to 6 % O2 per volume) the venous decrease of pO2 is similar to effects described in the first series with 2000 ppm CO at 1 ata: decrease of pO2 to about 10 torr and increase of blood sugar of about 100% compared to the initial value were observed. These results support the hypothesis that the increase of blood sugar after carbon monoxide intoxication is induced by the nonspecific oxygen deficiency of the organism — caused by CO-poisoning — and is therefore not primarily specific for the CO concentration of blood and tissue.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 289 (1975), S. 217-227 
    ISSN: 1432-1912
    Keywords: Digitoxin ; Intestinal Transport ; Dose Dependence ; Functional Asymmetry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary On everted jejunal segments of mice the transfer and tissue uptake of 3H-digitoxin, over a concentration range from 2×10−10–1×10−4M, was investigated from the mucosal (“m”) to the serosal (“s”) side as well as in the opposite direction. 1. The time course of the absorption of 3H-digitoxin and some other compounds investigated (glucose, urea, p-aminohippurate) gave evidence of functional integrity throughout the 75 min-periods of the experiments. 2. When 3H-digitoxin was applied to the mucosal side the permeability coeffcient showed a dose-dependent increase but returned to lower values at higher concentrations. When 3H-digitoxin was administered to the serosal side the permeability coefficient showed a dose-dependent decrease at high concentrations. The ratio of both coefficients “m” → “s”/“s” → “m” increased dose-dependently from 0.4–2.6. 3. The uptake of 3H-digitoxin — applied on the serosal side — into the tissue was independent of dose. However, having administered 3H-digitoxin on the mucosal side the tissue accumulation was 2–5 fold higher and the tissue/medium (T/M) ratio increased within the concentration range from 3.0–9.0. 4. Under DNP (1 mM) the asymmetry and dose dependence of the permeability and tissue uptake of 3H-digitoxin observed in controls were almost abolished. Therefore it is likely that the transfer of 3H-digitoxin in the intestine involves a mechanism more complex than simple diffusion. The existence of more than a two compartment system and/or the contribution of an active transport mechanism is suggested.
    Type of Medium: Electronic Resource
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