GLORIA

GEOMAR Library Ocean Research Information Access

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: 1432-0878
    Keywords: Key words: Osteoclasts – Mononuclear osteoclast precursor cells (MOPC) – Carbonic anhydrase II-mRNA – Calcitonin – Gene expression – In situ hybridization-quantitation – Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Carbonic anhydrase II (CA II), an enzyme catalyzing the interconversion of CO2 and water to HCO3 – and protons, has a key role in osteoclastic bone resorption, but little is known of the regulation of CA II gene expression by calcitonin. Analysis of mRNA in osteoclasts has been difficult because of the problems of obtaining sufficient number of purified osteoclasts from bone. In this study, however, we have investigated the regulation of CA II mRNA in rat osteoclasts and their putative mononuclear precursors by using in situ hybridization. We have found that the CA II gene is expressed at high levels in osteoclasts and what are probably their maturing mononuclear precursors. Measurement of CA II mRNA in cultured osteoclasts and their putative mononuclear precursor cells by cytophotometry provided evidence that calcitonin, a direct inhibitor of mammalian osteoclast activity, reduces the levels of CA II mRNA in a dose dependent manner; maximum reduction was observed at a concentration of 100pM of calcitonin. In addition, calcitonin reduced the number of CA II mRNA-positive mononuclear precursor cells. The results also suggest that expression of the CA II gene is a feature of cells committed to the osteoclast lineage.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-0878
    Keywords: Osteoclasts ; Mononuclear osteoclast precursor cells (MOPC) ; Carbonic anhydrase II-mRNA ; Calcitonin ; Gene expression ; In situ hybridization-quantitation ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Carbonic anhydrase II (CA II), an enzyme catalyzing the interconversion of CO2 and water to HCO 3 − and protons, has a key role in osteoclastic bone resorption, but little is known of the regulation of CA II gene expression by calcitonin. Analysis of mRNA in osteoclasts has been difficult because of the problems of obtaining sufficient number of purified osteoclasts from bone. In this study, however, we have investigated the regulation of CA II mRNA in rat osteoclasts and their putative mononuclear precursors by using in situ hybridization. We have found that the CA II gene is expressed at high levels in osteoclasts and what are probably their maturing mononuclear precursors. Measurement of CA II mRNA in cultured osteoclasts and their putative mononuclear precursor cells by cytophotometry provided evidence that calcitonin, a direct inhibitor of mammalian osteoclast activity, reduces the levels of CA II mRNA in a dose dependent manner; maximum reduction was observed at a concentration of 100pM of calcitonin. In addition, calcitonin reduced the number of CA II mRNA-positive mononuclear precursor cells. The results also suggest that expression of the CA II gene is a feature of cells committed to the osteoclast lineage.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 0730-2312
    Keywords: monocyte chemoattractant protein-1 ; gene expression ; pig artery ; balloon injury ; monocyte/macrophages ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Monocyte chemoattractant protein-1 (MCP-1) and interleukin-8 (IL-8) are potent chemokines which attract circulating monocytes and neutrophils respectively to inflamed tissues. JE/MCP-1 gene expression has been previously studied in rabbit aortae after endothelial denudation and the rapid appearance of this transcript was thought to precede emigration of phagocytes. We now report MCP-1 gene expression following de-endothelialization of iliac arteries in the pig, a species which can develop spontaneous atherosclerosis. Using Northern blot analysis, we demonstrated that MCP-1 mRNA was rapidly induced in pig arteries at 2 h and continued to increase to reach a maximum at 8 h before returning to low levels at 16-24 h after injury. The increase seen for MCP-1 mRNA at 8 h was also observed for IL-8 mRNA but was not apparent for growth-related gene expressions, urokinase-type plasminogen activator (u-PA), and plasminogen activator inhibitor-1 (PAI-1). Since smooth muscle cells, endothelial cells, and phagocytes are all capable of expressing MCP-1, we examined pig arteries for immunostaining using a monoclonal antibody to human MCP-1 (5D3-F7). At 8 h after injury, the predominant cell type staining positive for MCP-1 was the monocyte/macrophage. Staining was also observed in occasional scattered neutrophils, but MCP-1 protein could not be detected in smooth muscle cells or on extracellular matrix within the sensitivity constraints posed by our methodology. Our results are consistent with invading monocyte/macrophages having a major input into the production of this chemokine in the arterial wall following injury. The fact that MCP-1 expression accompanied monocyte/macrophage presence in damaged artery, rather than preceding it, is suggestive that continued MCP-1 expression is required for functions other than chemoattraction. © 1996 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The process of recombinant human bone morphogenetic protein-2 (rhBMP-2)-induced endochondral ossification involves (1) the proliferation and differentiation of mesenchymal cells into chondroblasts and osteoblasts; (2) the production and maturation of cartilage and bone matrix; and (3) the differentiation of circulating osteoclast precursor cells into osteoclasts. Currently the molecular mechanisms of these complex sequential events are unknown. It seemed reasonable to us to assume that communication between cells through soluble mediators during bone induction by rhBMP-2 may play an important role in the sequential differentiation of chondroblasts, osteoblasts, and osteoclasts. We have therefore used a human osteoblast-like initial transfectant cell line (HOBIT) to study the effect of rhBMP-2 on gene expression of interleukin-6 (IL-6) and transforming growth factor-β1 (TGF-β1), both of which affect osteogenesis and ostoeclastogenesis. Our results have demonstrated that rhBMP-2 acts on HOBIT cells to stimulate expression of IL-6 and TGF-β1 genes and the production of IL-6. Enhancement of gene expression of IL-6 and TGF-β1 by rhBMP-2 was both sensitive (half maximal effect at approximately 10 ng/ml) and potent (maximum induction was approximately four and threefold greater than controls, respectively). Time course studies showed that the induction of TGF-β1 and IL-6 mRNA occurs within short periods - 4 and 8 hours after exposure to rhBMP-2, respectively. Interestingly, these effects, however, were not accompanied by the mitogenic action of rhBMP-2. It suggests that rhBMP-2 enhances IL-6 and TGF-β1 production during osteogenesis and at least in part mediates the complex sequential differentiation of chondroblasts, osteoblasts, and osteoclasts during rhBMP-2-induced endochondral ossification. © 1994 wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...