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: 1432-0827
    Keywords: Key words: Osteoclast — Monocyte — Macrophage — Differentiation — Bone Resorption.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. Mononuclear precursors of the human osteoclast have been identified in both bone marrow and the circulation in man, but osteoclast membership of the mononuclear phagocyte system (MPS) and its precise cellular ontogeny remain controversial. We isolated human hematopoietic marrow cells, blood monocytes, and peritoneal macrophages and incubated each of these cell populations with UMR106 osteoblast-like cells on glass coverslips and dentine slices in both the presence and absence of 1,25 dihydroxyvitamin D3 (1,25(OH)2D3), macrophage-colony stimulating factor (M-CSF), and dexamethasone. Cells isolated from peripheral blood and peritoneal dialysis fluid were positive only for monocyte/macrophage markers (CD11a, CD11b, CD14, and HLA-DR) and negative for osteoclast markers [tartrate-resistant acid phosphatase (TRAP), vitronectin reception (VNR), and calcitonin (CT) receptors and did not form resorption pits on dentine slices after 24 hours in culture. Similarly marrow cells did not form resorption pits on dentine slices after 24 hours in culture. However, after 14 days in co-culture with UMR106 cells, in the presence of 1,25(OH)2D3 and M-CSF, numerous TRAP, CT receptor, and VNR-positive multinucleated cells capable of extensive lacunar resorption were formed in co-cultures of all these preparations. The presence of 1,25 (OH)2D3, M-CSF, and UMR106 were absolute requirements for osteoclast differentiation. It is concluded that precursor cells capable of osteoclast differentiation are present in the marrow compartment, the monocyte fraction of peripheral blood, and in the macrophage compartment of extraskeletal tissues and that these cells are capable of differentiating into mature functional osteoclasts. These findings argue in favor of osteoclast membership of the human MPS.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-0827
    Keywords: Key words: Osteoclast — Differentiation — Bone resorption — Prostaglandins.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. The effect of prostaglandins (PGs) on osteoclast differentiation, an important point of control for bone resorption, is poorly understood. After an initial differentiation phase that lasts at least 4 days, murine monocytes, cocultured with UMR106 osteoblastic cells (in the presence of 1,25-dihydroxyvitamin D3) give rise to tartrate-resistant acid phosphatase (TRAP) positive osteoclast-like cells that are capable of lacunar bone resorption. PGE2 strongly inhibits TRAP expression and bone resorption in these cocultures. To examine further the cellular mechanisms associated with this inhibitory effect, we added PGE2 to monocyte/UMR106 cocultures at specific times before, during, and after this initial 4-day differentiation period. To determine whether this PGE2 inhibition was dependent on the type of stromal cell supporting osteoclast differentiation, we also added PGE2 to cocultures of monocytes with ST2 preadipocytic cells. Inhibition of bone resorption was greatly reduced when the addition of PGE2 to monocyte/UMR106 cocultures was delayed until the fourth day of incubation; when delayed until the seventh day, inhibition did not occur. PGE2 inhibition of bone resorption was concentration-dependent and at 10−6 M was also mediated by PGE1 and PGF2α. In contrast to its effects on monocyte/UMR106 cocultures, PGE2 stimulated bone resorption in monocyte/ST2 cocultures. Both ST2 cells and UMR106 cells were shown to express functional receptors for PGE2. These results show that PGs strongly influence the differentiation of osteoclast precursors and that this effect is dependent not only on the type and dose of PG administered, but also on the nature of the bone-derived stromal cell supporting this process.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1573-6865
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The feasibility of using scanning electron microscopy (SEM) to identify the position of specific DNA sequences was examined using a Y chromosome ‘specific’ probe (pHY2.1). Tests were carried out on chromosome spreads hybridizedin situ with biotinylated pHY2.1. Chromosomal sites of hybridization of the probe were localized by an indirect immunohistochemical procedure which resulted in a gold product which could be amplified by silver precipitation. In the SEM, the specific location of the probe was easily identified due to the enhanced signal produced by the gold—silver complex. The probe was localized both on the long arm of the Y chromosome and within interphase nuclei. It was found that SEM was more sensitive than light microscopy since the probe could be identified without silver amplification. With refinements to the technique, SEM could provide a useful method for high resolution localizing of unique DNA sequences (i.e. single copy genes).
    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...