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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 179 (1996), S. 245-254 
    ISSN: 1432-1351
    Keywords: Bat ; Orientation ; Vision ; Echolocation ; Cumulative navigation error
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The orientation behaviour of bats (Phyllostomus discolor, Phyllostomidae), flying inside an octagonal “roost-like” chamber (ø: 100cm; h: 150cm) was examined. It has been shown that the bats begin turning manoeuvres during flight by turning their head towards the direction they intend to proceed to. During early phases of the flights, cumulative navigation errors were evident, indicating that endogenous spatial information plays a major role in the orientation of the bats. During later phases of the flight this error is diminished again. So it can be concluded that the bats start to use exogenous spatial information for orientation while approaching the target. In order to investigate the relative importance of vision, echolocation and endogenous spatial information for approaching the roost, the landing lattices inside the test arena were changed for non-grid dummies. We found that: 1. combined visual and endogenous information are more important than echoacoustical cues, 2. the bats learned quickly to switch their orientation behaviour in order to get a better performance in avoiding the dummies, 3. the learning performance was influenced by the visual similarity of dummies and the real landing lattice.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1435-2451
    Keywords: Lebertransplantation ; Warme Ischämie ; Organkonservierung ; Kalte Konservierung ; Normotherme Perfusion ; Reperfusion ; Liver transplantation ; Warm ischemia ; Organ preservation ; Cold storage ; Normothermic perfusion ; Reperfusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Warm ischemia is known to induce substantial damage to the liver parenchyma. With respect to clinical liver transplantation, the tolerance of the liver to warm ischemia and the preservation of these organs have not been studied in detail. In isolated reperfused pig livers we proceeded according to the following concept: Livers were subjected to 1 or 3 h of warm ischemia. Subsequently, these organs were preserved by either normothermic perfusion or cold storage (histidine-tryptophan-α-ketoglutarate, HTK) for 3 h each. After storage, liver function was assessed in a reperfusion circuit for another 3 h. Parameters under evaluation were bile flow, perfusion flow, oxygen consumption, enzyme release into the perfusate (creatine kinase, glutamic oxaloacetic transaminase (GOT), lactic dehydrogenase, and glutamic pyruvic transaminase), and histomorphology. Damage to the liver was lowest after warm ischemia of 1 h. The results after cold storage were superior to those after normothermic perfusion (GOT: 3.2±0.3 and 2.6±0.2 U/g liver; cumulative bile production: 14.7±2.1 and 9.4±1 ml, respectively;P〈0.05). In contrast, we found substantial damage at the end of reperfusion in livers undergoing 3 h of warm ischemia under both preservation techniques with severe hepatocellular pyknoses and essentially altered nonparenchymal cells. The results suggest that pig livers undergoing 1 h of warm ischemia and cold storage for 3 h with HTK solution may lead to functioning after transplantation.
    Notes: Zusammenfassung Die Verwendung von Lebern mit einer Vorschädigung durch warme Ischämie zur Transplantation wird kontrovers diskutiert. Im Modell der isoliert reperfundierten Schweineleber wurden nach vorausgegangener warmer Ischämie von 1 oder 3 h die Konservierungskonzepte „kalte Konservierung mit HTK-Lösung (Histidin-Tryptophan-α-Ketoglutarat)“ und „normotherme Perfusion“ für jeweils 3 h verglichen. Während einer 3 stündigen Reperfusion wurden neben einer lichtmikroskopischen Auswertung Gallefluß, Perfusionsfluß, Sauerstoffverbrauch und Enzymfreisetzung (Creatin-Kinase, Glutamat-Oxalacetat-Transaminase, Glutamat-Pyruvat-Transaminase und Laktat-Dehydrogenase) gemessen. Nach 1 stündiger warmer Ischämie führte die kalte Konservierung im Vergleich zur normothermen Perfusion zu einer geringeren Schädigung (GOT: 3,2±0,3 und 2,6±0,2 U/g Leber; Gesamtgallefluß: 14,7±2,1 und 9,4±1 ml;P〈0,05). Nach einer warmen Ischämie von 3 h waren bei beiden Konservierungsverfahren die Veränderungen erheblich. Die lichtmikroskopische Untersuchung zeigte Pyknosen von Hepatozyten und sinusoidalen Zellen mit teilweiser Auslösung aus dem Zellverband. Die Ergebnisse belegen, daß im Modell der isoliert reperfundierten Schweineleber eine warme Ischämie von 1 h toleriert wird. Für die Konservierung dieser vorgeschädigten Organe kann das Konzept der hypothermen Konservierung mit HTK-Lösung für einen Zeitraum bis zu 3 h empfohlen werden.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1435-2451
    Keywords: Schlüsselwörter Lebertransplantation ; Warme Ischämie ; Organkonservierung ; Kalte Konservierung ; Normotherme Perfusion ; Reperfusion ; Key words Liver transplantation ; Warm ischemia ; Organ preservation ; Cold storage ; Normothermic perfusion ; Reperfusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Warm ischemia is known to induce substantial damage to the liver parenchyma. With respect to clinical liver transplantation, the tolerance of the liver to warm ischemia and the preservation of these organs have not been studied in detail. In isolated reperfused pig livers we proceeded according to the following concept: Livers were subjected to 1 or 3 h of warm ischemia. Subsequently, these organs were preserved by either normothermic perfusion or cold storage (histidine-tryptophan-α-ketoglutarate, HTK) for 3 h each. After storage, liver function was assessed in a reperfusion circuit for another 3 h. Parameters under evaluation were bile flow, perfusion flow, oxygen consumption, enzyme release into the perfusate (creatine kinase, glutamic oxaloacetic transaminase (GOT), lactic dehydrogenase, and glutamic pyruvic transaminase), and histomorphology. Damage to the liver was lowest after warm ischemia of 1 h. The results after cold storage were superior to those after normothermic perfusion (GOT: 3.2±0.3 and 2.6±0.2 U/g liver; cumulative bile production: 14.7±2.1 and 9.4±1 ml, respectively; P〈0.05). In contrast, we found substantial damage at the end of reperfusion in livers undergoing 3 h of warm ischemia under both preservation techniques with severe hepatocellular pyknoses and essentially altered nonparenchymal cells. The results suggest that pig livers undergoing 1 h of warm ischemia and cold storage for 3 h with HTK solution may lead to functioning after transplantation.
    Notes: Zusammenfassung Die Verwendung von Lebern mit einer Vorschädigung durch warme Ischämie zur Transplantation wird kontrovers diskutiert. Im Modell der isoliert reperfundierten Schweineleber wurden nach vorausgegangener warmer Ischämie von 1 oder 3 h die Konservierungskonzepte ,,kalte Konservierung mit HTK-Lösung (Histidin-Tryptophan-α-Ketoglutarat)`` und ,,normotherme Perfusion`` für jeweils 3 h verglichen. Während einer 3 stündigen Reperfusion wurden neben einer lichtmikroskopischen Auswertung Gallefluß, Perfusionsfluß, Sauerstoffverbrauch und Enzymfreisetzung (Creatin-Kinase, Glutamat-Oxalacetat-Transaminase, Glutamat-Pyruvat-Transaminase und Laktat-Dehydrogenase) gemessen. Nach 1 stündiger warmer Ischämie führte die kalte Konservierung im Vergleich zur normothermen Perfusion zu einer geringeren Schädigung (GOT: 3,2±0,3 und 2,6±0,2 U/g Leber; Gesamtgallefluß: 14,7±2,1 und 9,4±1 ml; P〈0,05). Nach einer warmen Ischämie von 3 h waren bei beiden Konservierungsverfahren die Veränderungen erheblich. Die lichtmikroskopische Untersuchung zeigte Pyknosen von Hepatozyten und sinusoidalen Zellen mit teilweiser Auslösung aus dem Zellverband. Die Ergebnisse belegen, daß im Modell der isoliert reperfundierten Schweineleber eine warme Ischämie von 1 h toleriert wird. Für die Konservierung dieser vorgeschädigten Organe kann das Konzept der hypothermen Konservierung mit HTK-Lösung für einen Zeitraum bis zu 3 h empfohlen werden.
    Type of Medium: Electronic Resource
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