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  • 1
    Electronic Resource
    Electronic Resource
    Requirement of osteoblastic cells for the fusion of preosteoclasts (1998)
    Springer
    Journal of bone and mineral metabolism 16 (1998), S. 151-157 
    Details
    ISSN: 1435-5604
    Keywords: Key words: osteoclast ; fusion ; preosteoclast ; osteoblast ; calcitonin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract: The osteoclasts, which play an essential role in bone resorption, are multinucleated cells (MNCs). They are formed by the fusion of mononuclear preosteoclasts (pOCs). However, because of the difficulty of isolating the pOCs, the process of fusion of pOCs has not been elucidated. To establish a fusion assay system, we succeeded in isolating pOCs that are not contaminated with MNCs and osteoblastic cells from the coculture of mouse bone marrow cells and osteoblastic cells. When pOCs were cultured in the presence of osteoblastic cells, the fusion of pOCs into MNCs took place within 24 h. No MNCs were formed in the absence of osteoblastic cells. The number of MNCs formed by the fusion of pOCs was dependent on the number of both pOCs and osteoblastic cells in the culture. Osteoblastic cells were also required for bone resorption by the osteoclasts that were formed by the fusion of pOCs. Osteotropic hormones, such as 1α,25-dihydroxy vitamin D3 [1α,25(OH)2D3] and parathyroid hormone (PTH), did not affect the fusion and pit formation of pOCs in the absence of osteoblastic cells. Eel calcitonin (eCT), however, significantly inhibited the fusion of pOCs induced by osteoblastic cells. These results suggest that the fusion of pOCs was induced by the direct contact between pOCs and osteoblastic cells..
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s007740050039
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  • 2
    Electronic Resource
    Electronic Resource
    Receptor activator of NF-κB ligand induces the fusion of mononuclear preosteoclasts into multinucleated osteoclasts (2000)
    Springer
    Cytotechnology 33 (2000), S. 203-211 
    Details
    ISSN: 1573-0778
    Keywords: fusion ; IL-1β ; NF-κB ; osteoclast ; RANKL
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The osteoclasts are bone-resorbing multinucleatedcells formed by the fusion of mononuclearpreosteoclasts (pOCs) of hematopoietic origin.Although receptor activator of NF-κBligand (RANKL) has been shown to regulate osteoclastdifferentiation and function, its effect on the fusionof pOCs into multinucleated osteoclast-like cells(OCLs) has not been known. Using our fusion assaysystem, that is not contaminated with multinucleatedcells (MNCs) and osteoblastic cells, we determined theeffect of RANKL on the fusion of pOCs into MNCs. WhenpOCs were cultured on the plates, most of pOCs diedand disappeared from the plates within 24 h in theabsence of additives, but pOCs were fused to MNCswithin 6 h in the presence of RANKL. RANKL-inducedMNCs showed typical properties of OCL such astartrate-resistant acid phosphatase (TRAP) activity,actin ring formation, and bone-resorbing activity. Thefusion of pOCs into OCLs induced by osteoblastic cellsor RANKL was inhibited by OPG/OCIF, but that inducedby IL-1β was not. Both RANKL- andIL-1β-induced OCL formation from pOCs wasinhibited by ZLLL-H, a peptide inhibitor ofproteasome. These findings indicate that RANKLsupports the survival of pOCs and induces the fusionof pOCs into OCLs and suggest that NF-κBactivation is involved in these processes induced byRANKL and IL-1β.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008198120670
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  • 3
    Electronic Resource
    Electronic Resource
    Immunomodulating activities of polysaccharide fractions from dried safflower petals (1997)
    Springer
    Cytotechnology 25 (1997), S. 205-211 
    Details
    ISSN: 1573-0778
    Keywords: B cell ; Carthamus tinctorius L. ; cytokine ; lipopolysaccharides ; macrophages ; polysaccharide ; safflower
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract In the course of screening for immunomodulators, we found a significant blastogenic activity specific for splenic B cells in the extracts of safflower (Carthamus tinctorius L.). Active fractions termed SF1 and SF2 were purified from dried petals of safflower by boiling water extraction, ethanol precipitation and Sepharose CL-2B column chromatography. The elution profiles of the gel filtration indicated that the molecular weight of SF1 and SF2 was estimated to be more than 100 kD. Major components of SF1 and SF2 seem to be polysaccharides, and structural analysis of alditol acetate derivatives by GC-MS revealed some differences between SF1 and SF2 in the sugar component. Biological activities of SF1 and SF2 on B cells and macrophages were examined in comparison with lipopolysaccharides (LPS). SF1 and SF2 induced both the proliferation and the IgM production of B cells to the equivalent level as those induced by LPS. In macrophages, SF1 and SF2 effectively stimulated the production of NO. However, SF1 stimulated the production of IL-1, IL-6, and TNF as much as LPS, while SF2 induced them only weakly or not at all. Thus, these results suggest that SF1 and SF2 activate B cells and macrophages in different mechanisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007947329496
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  • 4
    Electronic Resource
    Electronic Resource
    Osteoblastic cells induce fusion and activation of osteoclasts through a mechanism independent of macrophage-colony-stimulating factor production (1999)
    Springer
    Cell & tissue research 298 (1999), S. 327-334 
    Details
    ISSN: 1432-0878
    Keywords: Preosteoclasts Osteoclasts Cell survival Receptor activator of NF-κB ligand (RANKL) Bone Cell culture Mouse (B6C3)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Fusion and activation of osteoclasts are the final two events in osteoclastic bone resorption. To investigate the regulatory mechanism of these events, mononuclear osteoclasts (preosteoclasts, pOCs) were isolated from co-cultures of mouse osteoblastic cells and bone marrow cells. Most of the pOCs cultured without any additives died within 12 h. Survival of pOCs was supported by addition of either osteoblastic cells or macrophage-colony-stimulating factor (M-CSF). pOCs began to fuse with each other after culture for 12 h in the presence of osteoblastic cells or M-CSF. However, the properties of multinucleated osteoclast-like cells (OCLs) induced by osteoblastic cells were considerably different from those induced by M-CSF. Fusion of pOCs induced by osteoblastic cells was retarded after culture for 24 h. In contrast, M-CSF-induced fusion of pOCs continued throughout the 48-h culture period, which was not inhibited by addition of calcitonin. When pOCs together with osteoblastic cells were cultured for 48 h on dentine slices, many resorption pits were formed on the slices. Calcitonin completely inhibited the fusion and pit-forming activity of pOCs treated with osteoblastic cells. Resorption pits were hardly detected on dentine slices in pOC cultures treated with M-CSF. Osteoblastic cells prepared from osteopetrotic (op/op) mice, which cannot produce functional M-CSF, stimulated the fusion and pit-forming activity of pOCs. Recombinant RANKL (receptor activator of NF-κB ligand), a cytokine which is produced by osteoblastic cells and is responsible for osteoclast differentiation, induced the fusion and pit-forming activity of pOCs. These results suggested that osteoblastic cells are involved in fusion and activation of osteoclasts through a mechanism independent of M-CSF production. RANKL appears to be responsible for fusion and activation of osteoclasts induced by osteoblastic cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004419900092
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