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  • 1
    Electronic Resource
    Electronic Resource
    Selective reduction of anaphase B in quinacrine-treated PtK1 cells (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 14 (1989), S. 220-229 
    Details
    ISSN: 0886-1544
    Keywords: microtubules ; mitosis ; kinetochore ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Quinacrine, an acridine derivative which competitively binds to ATP binding sites, has previously been shown to cause the reorganization of metaphase spindle microtubules (MTs) due to changes in interactions of non-kinetochore microtubules (nkMTs) of opposite polarity (Armstrong and Snyder: Cell Motil. Cytoskeleton 7:10-19, 1987). In the study presented here, mitotic PtK1 cells were treated in early anaphase with concentrations of quinacrine ranging from 2 to 12 μM to determine energy requirements for chromosome motion. The rate and extent of chromosome-to-pole movements (anaphase A) were not affected by these quinacrine treatments. The extent of anaphase B (kinetochore-kinetochore separation) was reduced with increasing concentrations of quinacrine. Five micromolar quinacrine reduced the extent of kinetochore-kinetochore separation by 20%, and addition of 12 μM quinacrine reduced the kinetochore-kinetochore separation by 40%. To determine the role of nkMTs in anaphase spindle elongationquinacrine-treated metaphase cells were treated with hyperosmotic sucrose concentrations, and spindle elongation was measured (Snyder et al.: Eur J. Cell Biol. 39:373-379, 1985). Metaphase cells treated with 2-10 μM concentrations of quinacrine for 2-5 min reduced spindle lengths by 10-50% prior to 0.5 M sucrose treatment for 5 min. This treatment showed a significant reduction in the ability of sucrose to induce spindle elongation in cells pretreated with quinacrine. As spindle length and birefringence was reduced by quinacrine treatment, sucrose-induced elongation was concomitantly diminished. These data suggest that quinacrine-sensitive linkages are necessary for anaphase B motions. Reduction in these linkages and/or MT length in the nkMT continuum may reduce the ability of the nkMTs to hold compression at metaphase. This form of energy is thought to drive a significant proportion of normal anaphase B in PtK1 cells and sucrose-induced metaphase spindle elongation.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970140208
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  • 2
    Electronic Resource
    Electronic Resource
    Transformation of mucocartilage to a definitive cartilage during metamorphosis in the sea lamprey, Petromyzon marinus (1987)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 194 (1987), S. 1-21 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: An ultrastructural analysis of the development of adult piston (tongue) cartilage in the ventromedial longitudinal bar (VMLB), an area of larval mucocartilage, was undertaken in the lamprey, Petromyzon marinus, in order to clarify the relationship between these two unique larval and adult connective tissues. At the onset of metamorphosis, the mucocartilage fibroblasts dedifferentiate into a “mesenchymal” cell type. Migration of unspecialized cells from surrounding tissues plays an important role in the development of a cellular “embryonic” tissue in the VMLB. Degradation of the mucocartilage extracellular matrix (ECM) by the unspecialized cells seems to occur prior to cartilage differentiation. This event is followed by the appearance of a blastema of undifferentiated cells, which expands by proliferation of cells in the core of the VMLB. The cells of the blastema subsequently differentiate into chondroblasts, which secrete adult ECM components consisting of 20-nm nonbanded fibrils, electron-dense branched lamprin fibrils, and proteoglycan. The present study suggests that mucocartilage, as a primitive or embryonic connective tissue, temporarily specializes to act as a skeletal support during larval life. Once metamorphosis is initiated, this tissue resumes an embryonic character (mesenchymal) and cartilage histogenesis takes place. The mechanism of cartilage development within the lamprey VMLB is similar to that observed in the chondrogenic system of higher vertebrates.
    Additional Material: 24 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051940102
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  • 3
    Electronic Resource
    Electronic Resource
    The brain venous system of the dog (1971)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 132 (1971), S. 479-490 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The venous system of the canine brain was investigated by gross dissection and by radiographs. The system was divided into four major groups of vessels: cerebral veins, central veins, cerebellar veins, and pontomedullary veins.The dorsal cerebral veins emptied into the dorsal sagittal sinus and the ventral cerebral veins entered the dorsal petrosal or transverse sinus. The internal system of cerebral veins, and the central veins, were drained by the great cerebral vein which entered the straight sinus. Cerebellar and pontomedullary veins flowed mainly to the sigmoid sinus.The venous system of the dog differed from the human configuration in several ways. In the dog the major dorsal cerebral veins entered the dorsal sagittal sinus by independent lacunae in the same direction as the flow of blood. A middle cerebral vein was not present in the dog but was replaced by a continuation of the caudal ventral cerebral vein. There was a basal vein in the dog but its main flow of blood was to the dorsal petrosal sinus; in man, this vein passes to the great cerebral vein. The entire venous system of the brain was plexiform and collateral circulation was prominent. The larger veins were identified radiographically.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001320406
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    Paper (German National Licenses)
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