ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1573-4978
    Keywords: bone ; intermediate filament ; nuclear matrix ; osteoblast ; osteosarcoma ; tissue matrix
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Treatment for osteosarcoma is problematic because there are no prognostic markers. Diagnosis is primarily limited to cytologic grading. Oncogenesis alters cell structure therefore osteoblast tissue matrix proteins (extracellular matrix, cytoskeletal, intermediate filament, and nuclear matrix proteins), components of the cell substructure, are candidates for osteosarcoma markers. Structural proteins of the extracellular matrix, e.g. the collagens, are useful for diagnosis but not for tumors that produce little osteoid. To identify principal cellular tissue matrix proteins that distinguish normal from transformed human osteoblasts, their expression in normal osteoblasts, two osteosarcoma cell lines, and three primary osteosarcoma tumors were compared. The tumors were graded as (i) intermediate, (ii) high, and (iii) high grade recurrent. The 1-D SDS/PAGE profiles of the major components of the nuclear matrix and intermediate filament fractions from normal osteoblasts did not vary with biopsy site, age, or sex of patients. These profiles included known cytoskeletal proteins and OB250, a ∼250 kD protein(s) observed in the intermediate filament fraction. A loss of protein bands, including OB250, was observed in the osteosarcoma cell lines and tumors. The intermediate and high grade tumors exhibited nearly identical protein profiles including potential tumor-specific proteins and collagen, consistent with the presence of intracellular collagen fibers in osteosarcoma. A microsequence was obtained for OT25, a novel low molecular weight protein observed in osteosarcoma cell lines. Fibrinogen γ-chain, a protein that mediates cell adhesion was recovered from the high grade recurrent tumor.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 67 (1997), S. 451-465 
    ISSN: 0730-2312
    Keywords: bone ; differentiation ; nuclear matrix ; osteoblast ; topoisomerase II ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The molecular mechanisms that mediate the transition from an osteoprogenitor cell to a differentiated osteoblast are unknown. We propose that topoisomerase II (topo II) enzymes, nuclear proteins that mediate DNA topology, contribute to coordinating the loss of osteoprogenitor proliferative capacity with the onset of differentiation. The isoforms topo II-α and -β, are differentially expressed in nonosseous tissues. Topo II-α expression is cell cycle-dependent and upregulated during mitogenesis. Topo II-β is expressed throughout the cell cycle and upregulated when cells have plateaued in growth. To determine whether topo II-α and -β are expressed in normal bone, we analyzed rat lumbar vertebrae using immunohistochemical staining. In the tissue sections, topo II-α was expressed in the marrow cavity of the primary spongiosa. Mature osteoblasts along the trabecular surfaces did not express topo II-α, but were immunopositive for topo II-β, as were cells of the marrow cavity. Confocal laser scanning microscopy was used to determine the nuclear distribution of topo II in rat osteoblasts isolated from the metaphyseal distal femur and the rat osteosarcoma cells, ROS 17/2.8. Topo II-α exhibited a punctate nuclear distribution in the bone cells. Topo II-β was dispersed throughout the interior of the nucleus but concentrated at the nuclear envelope. Serum starvation of the cells attenuated topo II-α expression but did not modulate expression of the β-isoform. These results indicate that the loss of osteogenic proliferation correlates with the downregulation of topo II-α expression. J. Cell. Biochem. 67:451-465, 1997. © 1997 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...