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  • Chemistry  (1)
  • Infectivity  (1)
  • 1980-1984  (2)
  • 1
    ISSN: 1432-1955
    Keywords: Trypanosoma brucei ; Cryopreservation ; Fine structure ; Infectivity ; Motility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die während der Tiefgefrierkonservierung vonTrypanosoma brucei mit Zusatz von 10% Glyzerin auftretenden feinstrukturellen Veränderungen wurden zu Beeinträchtigungen ihrer Motilität und Infektiosität in Beziehung gesetzt. Als Kontrollen wurden 1. Parasiten aus Frischblut infizierter Mäuse, 2. in PSG-3-Puffer erythrocytenfrei suspendierte Trypanosomen unmittelbar nach Passage durch DE-Zellulose, 3. nach 71 min Aufenthalt bei 4°C in PSG-Puffer mit Zusatz von 10% Glyzerin untersucht. Die Trypanosomen aus Frischblut zeigten bei optimaler Strukturerhaltung volle Motilität und Infektiosität. Bei etwa 50% der tiefgefrorenen Trypanosomen wurden morphologische Veränderungen festgestellt: Bildung bis 1 μm großer myelinartiger Figuren im Kinetoplast, in den Mitochondrien und im Cytoplasma. Spaltbildungen im Cytoplasma, die zur Bildung großer Vakuolen und zum Abtrennen des Cytoplasmas von der Pellicula führen, Verlust der Ribosomen, ballonartiges Aufblähen der Geißeltasche und Entstehung von mikrokristallinen Strukturen in den peroxisomenähnlichen Organellen (po-bodies). Veränderungen am Kern traten erst spät nach fortgeschrittenen Schädigungen im Cytoplasma, die zur Lyse führen, ein. Mit den morphologischen Veränderungen einhergehend wurde ein erheblicher Motilitäts- und Infektiositätsverlust beobachtet. Die Mehrzahl der Schäden wurde bereits bei den nicht tiefgefrorenen Blutflagellaten mit Glyzerinzusatz beobachtet. Anhand der Befunde dieses Kontrollansatzes wurde deutlich, daß die Ausbildung mikrokristalliner Strukturen in den peroxisomenähnlichen Organellen und der Verlust der Ribosomen allein als spezifische auf die Tiefgefrierung zurückzuführende Veränderungen anzusehen sind. Auch die Infektiosität war bereits im gleichen Maße in der Glyzerinkontrolle beeinträchtigt, während die Motilität noch relativ gut erhalten blieb. Obwohl bei den Trypanosomen beider PSG-3-Kontrollen nach Passage durch die Lanham-Säule geringfügige feinstrukturelle Veränderungen, wie z.B. Spaltbildungen, sichtbar wurden, konnte keine nennenswerte Beeinträchtigung ihrer Motilität und Infektiosität festgestellt werden, besonders nicht unmittelbar nach Säulendurchlauf.
    Notes: Abstract The ultrastructural changes occurring during deep-freeze storage ofTrypanosoma brucei after 10% glycerin had been added were compared with respect to the impairment of their motility and their infectivity. The following served as controls: (1) parasites from fresh blood taken from infected mice, (2)Trypanosoma suspended erythrocyte-free in PSG-buffer immediately after passage through DE cellulose, and (3)Trypanosoma after 71 min at 4°C in PSG-buffer with 10% glycerin. TheTrypanosoma from fresh blood exhibited, under optimum structural maintenance, complete motility and infectivity. The following morphologic changes were found in approximately 50% of the deep-frozenTrypanosoma: the formation of myelin-like figures of up to 1 μm in size in the kinetoplast, in the mitochondria, and in the cytoplasm; fissurations in the cytoplasm leading to development of large vacuoles and to the separation of the cytoplasm from the pellicle; dissipation of ribosomes; balloon-like inflation of the flagellar pocket; and the appearance of microcrystalline structures in the peroxisome-like organelles (po-bodies). Changes in the nucleus did not occur until the cytoplasm had suffered considerable damage which resulted in lysis. A significant loss in motility and infectivity was observed to go hand in hand with the morphologic changes. Much damage was also observed in the hemoflagellates which had not been deep-frozen and to which glycerin had been added. The findings from this control material clearly showed that only the formation of microcrystalline structures in the peroxisome-like organelles and the dissipation of the ribosomes can be regarded as specific changes attributable to the deepfreezing. The infectivity of the glycerin control was also impaired to the same degree, whereas the motility was relatively well maintained. Although slight microstructural changes as, for example, fissurations were evident in theTrypanosoma from both PSG-controls after their passage through the Lanham column, no significant impairment of their motility or infectivity could be detected, particularly not directly after their passage through the column.
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  • 2
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 3 (1981), S. 110-117 
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The corrosion behaviour of orthopaedic metal implants was studied in an animal experiment in which 30 rabbits had stainless steel plates implanted after a varization osteotomy of the tibiae of their hind legs for one year. ESCA was used for the investigation of the surfaces of the inplants. The removed plates were covered by an easily destroyable 3-5 nm thick oxidic layer which contained Cr(III), Fe(II), Fe(III), Mo(VI) and Mo(IV), but no Ni. This passive layer (and possibly also the nearest metal layer below it) is strongly enriched in Cr. Additionally, corrosion experiments with radioactivated implants in Ringer's solution demonstrated that the passivation of the stainless steel is accompanied by marked selective solution of the steel constituents. The observed solubilities (Co 〉 Ni 〉 Fe 〉 Mo 〉 Cr) are inversely correlated with the abundance of the respective element in the passive layer. The trace element composition of the tissues was measured by instrumental neutron activation analysis. It turned out that the actual burdening of the tissues surrounding the implants by corrosion products is exhibited by strong enrichments of the elements Cr, Fe, Co, Ni and Mo relative to their normal concentrations. While Cr, Co, Ni and Mo are abundant in fairly constant ratios in the contact tissues, the excess of Fe is influenced by biological regulation mechanisms. The extent to which the distribution patterns of steel-specific elements in animal (and human) tissues can be explained by the dissolution of the steel during the passivation process is discussed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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