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Undifferentiated Mesenchymal Cells (undifferentiated + mesenchymal_cell)
Selected AbstractsBone morphogenetic protein-2 modulation of chondrogenic differentiation in vitro involves gap junction-mediated intercellular communicationJOURNAL OF CELLULAR PHYSIOLOGY, Issue 2 2002Wei Zhang Undifferentiated mesenchymal cells in the limb bud integrate a complex array of local and systemic signals during the process of cell condensation and chondrogenic differentiation. To address the relationship between bone morphogenetic protein (BMP) signaling and gap junction-mediated intercellular communication, we examined the effects of BMP-2 and a gap junction blocker 18 alpha glycyrrhetinic acid (18,-GCA) on mesenchymal cell condensation and chondrogenic differentiation in an in vitro chondrogenic model. We find that connexin43 protein expression significantly correlates with early mesenchymal cellular condensation and chondrogenesis in high-density limb bud cell culture. The level of connexin43 mRNA is maximally upregulated 48 h after treatment with recombinant human BMP-2 with corresponding changes in protein expression. Inhibition of gap junction-mediated intercellular communication with 2.5 ,M 18,-GCA decreases chondrogenic differentiation by 50% at 96 h without effects on housekeeping genes. Exposure to 18,-GCA for only the first 24,48 h after plating does not affect condensation or later chondrogenic differentiation suggesting that gap junction-mediated intercellular communication is not critical for the initial phase of condensation but is important for the onset of differentiation. 18,-GCA can also block the chondrogenic effects of BMP-2 without effects on cell number or connexin43 expression. These observations demonstrate 18,-GCA-sensitive regulation of intercellular communication in limb mesenchymal cells undergoing chondrogenic differentiation and suggest that BMP-2 induced chondrogenic differentiation may be mediated in part through the modulation of connexin43 expression and gap junction-mediated intercellular communication. J. Cell. Physiol. 193: 233,243, 2002. © 2002 Wiley-Liss, Inc. [source] Osteosarcoma of the testisINTERNATIONAL JOURNAL OF UROLOGY, Issue 3 2006HICHAM TAZI Abstract, This report describes a case of primary osteosarcoma of the testis in a 60-year-old man. Treatment consisted of an inguinal orchiectomy with no adjuvant therapy. The patient is alive and doing well without recurrent disease at 18 months after diagnosis. Only three reports have been published on primary osteosarcoma of the testis. The origin of this tumor from undifferentiated mesenchymal cells or from a malignant transformation of pre-existing teratomatous elements is still unclear. Management guidelines are difficult to establish due to the rarity of such tumors, but inguinal orchiectomy with careful follow up appears to be sufficient treatment. [source] Differential Expression Patterns of Runx2 Isoforms in Cranial Suture MorphogenesisJOURNAL OF BONE AND MINERAL RESEARCH, Issue 5 2001Mi-Hyun Park Abstract Runx2 (previously known as Cbfa1/Pebp2,A/AML3), a key transcription factor in osteoblast differentiation, has at least two different isoforms using alternative promoters, which suggests that the isoforms might be expressed differentially. Haploinsufficiency of the Runx2 gene is associated with cleidocranial dysplasia (CCD), the main phenotype of which is inadequate development of calvaria. In spite of the biological relevance, Runx2 gene expression patterns in developing calvaria has not been explored previously, and toward this aim we developed three probes: pRunx2, which comprises the common coding sequence of Runx2 and hybridizes with all isoforms; pPebp2,A, which specifically hybridizes with the isoform transcribed with the proximal promoter; and pOsf2, which hybridizes with the isoform transcribed with the distal promoter. These probes were hybridized with tissue sections of mouse calvaria taken at various time points in development. Runx2 expression was localized to the critical area of cranial suture closure, being found in parietal bones, osteogenic fronts, and sutural mesenchyme. Pebp2,A and Osf2 showed tissue-specific expression patterns. The sites of Pebp2,A expression were almost identical to that of pRunx2 hybridization but expression was most intense in the sutural mesenchyme, where undifferentiated mesenchymal cells reside. The Osf2 isoform was strongly expressed in the osteogenic fronts, as well as in developing parietal bones, where osteopontin (OP) and osteocalcin (OC) also were expressed. However, in contrast to Pebp2,A, Osf2 expression did not occur in sutural mesenchyme. Pebp2,A also was expressed prominently in primordial cartilage that is found under the sutural mesenchyme and is not destined to be mineralized. Thus, Osf2 isoforms contribute to events later in osteoblast differentiation whereas the Pebp2,A isoform participates in a wide variety of cellular activities ranging from early stages of osteoblast differentiation to the final differentiation of osteoblasts. [source] Bone augmentation by onlay implant using recombinant human BMP-2 and collagen on adult rat skull without periosteumCLINICAL ORAL IMPLANTS RESEARCH, Issue 4 2000Masaru Murata The purpose of this study was to determine whether bone augmentation could be obtained by the composite of recombinant human bone morphogenetic protein-2 (rhBMP-2) and bioabsorbable atelocollagen when the periosteum was resected, and to compare the efficacy of the rhBMP-2/collagen implant and the collagen alone implant. The onlay implant was inserted into the space between the elevated galea aponeurotica and the skull without the periosteum of 10-month-old rats. The rhBMP-2/collagen implant resulted in osteoblasts differentiation under the galea at 1 week and active bone formation without a prior formation of cartilage. At 4 weeks, the bony trabeculae were interconnected and connected directly with the compact bone of the skull. Histomorphometric analysis at 4 weeks demonstrated that the rhBMP-2/collagen implant showed 92.5% in the volume of bone tissue, whereas the collagen alone showed 0%. The implanted collagen was gradually replaced by bone tissue in the presence of rhBMP-2. Our present results indicate that rhBMP-2 stimulates undifferentiated mesenchymal cells in the galea overlying the implant to proliferate and differentiate directly into osteoblasts on the carrier collagen fibers. The collagen matrix was stably placed on the skull and suitable as a substitute for rhBMP-2. The rhBMP-2/collagen onlay implant might be clinically applicable for bone augmentation even under the condition without the periosteum. [source] | ||||||||||