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  • Morphometry  (2)
  • Bone resorption  (1)
  • Chondriome  (1)
  • Springer  (3)
  • Blackwell Publishing Ltd
  • 1985-1989  (1)
  • 1980-1984  (2)
  • 1955-1959
Document type
Keywords
Publisher
  • Springer  (3)
  • Blackwell Publishing Ltd
Years
  • 1985-1989  (1)
  • 1980-1984  (2)
  • 1955-1959
Year
  • 1
    Electronic Resource
    Electronic Resource
    Cellular response to ectopically implanted silk sutures and osteopetrotic bone (1987)
    Springer
    Cell & tissue research 248 (1987), S. 79-88 
    Details
    ISSN: 1432-0878
    Keywords: Bone resorption ; Implantation ; Osteoclasts ; Osteopetrosis ; Mononuclear phagocytes ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Faulty osteoclasts, characteristic of the incisors-absent (ia) rat mutation of osteopetrosis, cause a resorptive defect which results in the persistence of immature, highly mineralized bone matrix. We implanted osteopetrotic bone subcutaneously into normal andia rats to determine ifia bone could induce functionally active and morphologically identifiable osteoclasts at the implant surface. Assays of45Ca released from the preparations showed that normal andia recipients were capable of equivalent cell-mediated release of Ca over a 2-week implant period, indicating that theia resorptive defect was not reproduced at the subcutaneous site. Freeze-thawed osteopetrotic bone released twice as much45Ca as normal bone. This difference was eliminated by collagenase treatment. Cellular profiles were similar in both normal andia animals regardless of the implant preparation. At 3 days after implantation, both bone and suture were surrounded by mononuclear cells. By 14 days, multinucleated cells appeared at the implant surfaces. Morphological comparison of implant-induced multinucleated cells and tibial osteoclasts indicated that bone-elicited multinucleated cells lacked the ruffled borders characteristic of normal osteoclasts or the extensive clear zones typical ofia osteoclasts, but more closely resembled suture-induced macrophage-polykaryons. We conclude that ectopically implantedia bone as compared to normal bone elicits a different functional response from structurally similar cell populations. Bone-elicited multinucleated cells could not be classified as active osteoclasts despite evidence of release of45Ca. Release of labeled Ca was probably due to the action of mononuclear phagocytes and macrophage-polykaryons rather than to osteoclastic resorption.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01239966
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Morphometric and chronobiological studies on the dynamics of the nuclear envelope and the nucleolus during mitosis of the colorless phytoflagellatePolytoma papillatum (1983)
    Springer
    Protoplasma 118 (1983), S. 19-35 
    Details
    ISSN: 1615-6102
    Keywords: Morphometry ; Mitosis ; Nuclear envelope ; Nucleolus ; Polytoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Quantitative electron microscopy of serial sections was used to study the cyclical changes in the nucleus ofPolytoma papillatum during its vegetative life cycle with special reference to mitosis. Particular attention was paid to the fluctuations in the nuclear volume, the nuclear envelope, and the nucleolus. Whereas a volumetric balance exists between the cell (100%) and the nucleus (ca. 8%) from early interphase to late anaphase, the nucleus-to-cell volume ratio is gradually reduced up to ca. 2% during telophase. This disproportion is gradually equalized during cytokinesis. The decrease in nuclear size is brought about by: (a) Constrictive abscission of hernia-like protrusions of the nucleus (“blebbing process”); (b) Ade novo production of membraneous septa across peripheral regions of the nucleus (“internal septation”). Just before or immediately after completion of this internal compartmentalization of the nucleus, the original envelope opens, releasing a portion of nucleoplasm into the cytoplasm (“membrane sluice process”); (c) Gaps in the nuclear envelope were occasionally found during telophase and may also permit nucleoplasm to leak out. Disorganization of the nucleolos, which is preceded by blending of its two major components (pars fibrosa, pars granulosa) starts at prophase via fragmentation. Subsequent dispersion continues until the nucleolus is more or less homogeneously distributed across the metaphase nucleus. During anaphase a good deal of the preexisting material recondenses around the separating chromosomes, but a considerable amount remains dispersed in the nucleoplasm and is extruded into the cytoplasm during nuclear volume reduction. Reorganization of the nucleolus occurs during telophase and early cytokinesis via further coalescence of the recondensed material and simultaneous reconstruction of the spatial separation of pars fibrosa and pars granulosa. Morphofunctional aspects of nucleo- and nucleologenesis are also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01284743
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  • 3
    Electronic Resource
    Electronic Resource
    Morphometric analysis of several intracellular events occurring during the vegetative life cycle of the unicellular algaPolytoma papillatum (1982)
    Springer
    Protoplasma 110 (1982), S. 185-195 
    Details
    ISSN: 1615-6102
    Keywords: Morphometry ; Life cycle ; Chondriome ; Nucleus ; Leucoplast ; Polytoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Quantitative electron microscopy of serial sections was used to study thePolytoma papillatum cell and some of its constituents (nucleus, chondriome, leucoplast) during its vegetative life cycle. The volumes of cells just entering into or passing through mitosis varied considerably and seemed to determine the number of subsequent division processes. Whereas a volumetric balance existed between the cell (100%) and the chondriome (8–9%) during the whole life cycle, there was a correlation between cell and nuclear volumes (8–10%) only during interphase growth and the onset of mitosis. At telophase the nucleus-to-cell-volume ratio was reduced to 2%, but gradually increased during cytokinesis (4.6% at early cytokinesis; 6.5% at late cytokinesis) until it reached the initial value again in newly formed daughter cells. The leucoplast-to-cell-volume ratio (10–26%) varied considerably without any recognizable dependence upon cell cycling. The mean short axis of mitochondrial profiles was proportional to the mean diameter (=thickness) of the mitochondria; the specific surface (outer membrane area per 100 μm3 mitochondrial volume), and the surface-to-volume ratio changed rhythmically. Changes in mitochondrial surface-to-volume ratio (Sc/Vc) were apparently correlated with changes in mitochondrial diameter (Dc). This relationship can be approximately described by the function Sc/Vc=4/Dc. Deviations of the surface-to-volume ratios of the nuclei from the surface-to-volume ratios of idealized spheres of equal size, indicating profound changes in nuclear shape, were found mainly during mitosis. Results were compared with those obtained from other morphometric investigations and discussed with regard to their functional meaning.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01283321
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