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  • 1
    ISSN: 1432-2307
    Keywords: Cyclic hematopoiesis ; Bone marrow ; Ultrastructure ; Nuclearcytoplasmic asynchrony ; Döhle-like bodies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The pathogenesis of cyclic hematopoiesis (CH) in the grey collie dog is still unknown. It has been proposed that periodic bursts of necrosis of the bone marrow neutrophils would induce cyclic arrests of the stem cell differentiation. In the present study, the sequential changes undergone by the erythroid and neutrophil series of the bone marrow of CH dogs were evaluated by electron microscopy. Erythroid cells presented quantitative periodic oscillations but the morphologic features of both immature and mature cells were normal. On the contrary, nonspecific necrotic changes were observed to occur in the myeloid series. Those abnormalities, which were more marked between days 9 and 11 of the cycle, mainly involved the immature cells and, to a lesser extent, the mature neutrophils. The number of necrotic cells was variable in different cycles, but always represented a small portion of the myeloid cells. In addition, few bone marrow macrophages displayed signs of phagocytic activity containing cell debris. The ultrastructural changes of the myeloid series were accompanied by an abnormal decrease of peroxidase activity and the permanence of large acid phosphatase-positive Golgi complexes in mature neutrophils, as defined by morphologic criteria. Döhle-like arrays of rough endoplasmic reticulum were present in many cells. Our findings suggest that an asynchronic development of myelocytes occurs as a result of regulatory abnormalities related to the congenital defect of the bone marrow which interferes with the differentiation and maturation of the stem cells. Necrosis in some myeloid cells would be a secondary phenomenon rather than a causal factor for the cyclic arrest of cell maturation as has been previously submitted. Furthermore, the small size of the necrotic cell population could not justify the production of “inhibitors” in sufficient amounts as to block the normal evolution of the bone marrow stem cell pool.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0878
    Keywords: Islets of Langerhans ; Grass-snake ; Crystalline B-granules ; Ultrastructure ; Crystallography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Kristalline B-Granula im Pankreas der Ringelnatter besitzen die Form von Rhombendodekaedern (a ≈ 11 nm, kubisch-raumzentriertes Gitter). Diese Diagnose wird abgeleitet von den Ergebnissen der dreidimensionalen Rekonstruktion von Serienschnitten, der optischen Diffraktometrie und aus dem Vergleich mit Kristallmodellen. Die Bedeutung kristalliner B-Granula wird erörtert.
    Notes: Summary Crystalline B-granules of grass-snake islets of Langerhans have been shown to possess the shape of rhombic dodecahedra (a ≈ 11 nm, cubic body-centered lattice). Three-dimensional reconstructions from serial sections, optical diffractometry and comparison with crystal models were the techniques utilized. The significance of crystalline B-granules is discussed.
    Type of Medium: Electronic Resource
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  • 3
    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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  • 4
    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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