The Experts below are selected from a list of 171 Experts worldwide ranked by ideXlab platform

Pamela Gehron Robey - One of the best experts on this subject based on the ideXlab platform.

  • Bone matrix rgd glycoproteins immunolocalization and interaction with human primary osteoblastic Bone Cells in vitro
    Journal of Bone and Mineral Research, 2009
    Co-Authors: Wojciech J Grzesik, Pamela Gehron Robey
    Abstract:

    The interaction of Cells with extraCellular matrix is essential for their anchorage, proliferation, migration, and differentiation. In Bone matrix there are multiple glycoproteins that contain the integrin-binding RGD sequence: fibronectin (FN), thrombospondin (TSP), osteopontin (OPN), Bone sialoprotein (BSP), type I collagen (COLL I), and vitronectin (VN). In this study, the localization of TSP, FN, VN, and several integrins within developing human long Bone using immunohistochemical methods was examined, as was the effect of all Bone RGD proteins on the adhesion of human osteoblastic Cells. Thrombospondin, fibronectin, and vitronectin showed distinct localization patterns within Bone tissue. TSP was found mainly in osteoid and the periosteum; VN appeared to be present mainly in mature Bone matrix. FN was present in the periosteum as well as within both mature and immature Bone matrix. Using a panel of antiintegrin antibodies we found that Bone Cells in vivo and in vitro express α4, αv, α5β1, αvβ3, and β3/β5 integrins, and these receptors are for the most part expressed on all Bone Cells at different stages of maturation with quantitative rather than qualitative variations, with the exception of α4, which is expressed mainly by osteoblasts. Cell Attachment assays were performed using primary human Cells of the osteoblastic lineage under serum-free conditions. COLL I, TSP, VN, FN, OPN, and BSP promoted Bone Cell Attachment in a dose-dependent manner and were equivalent in action when used in equimolar concentrations. In the presence of GRGDS peptide in the medium, the adhesion to BSP, OPN, and VN was almost completely blocked (10, 10, and 15% of control, respectively), and Attachment to FN, COLL I, and TSP was only slightly decreased (80, 75, and 55%, respectively). These results suggest that human Bone Cells may use RGD-independent mechanisms for Attachment to the latter glycoproteins.

  • Bone matrix rgd glycoproteins immunolocalization and interaction with human primary osteoblastic Bone Cells in vitro
    Journal of Bone and Mineral Research, 2009
    Co-Authors: Wojciech J Grzesik, Pamela Gehron Robey
    Abstract:

    The interaction of Cells with extraCellular matrix is essential for their anchorage, proliferation, migration, and differentiation. In Bone matrix there are multiple glycoproteins that contain the integrin-binding RGD sequence: fibronectin (FN), thrombospondin (TSP), osteopontin (OPN), Bone sialoprotein (BSP), type I collagen (COLL I), and vitronectin (VN). In this study, the localization of TSP, FN, VN, and several integrins within developing human long Bone using immunohistochemical methods was examined, as was the effect of all Bone RGD proteins on the adhesion of human osteoblastic Cells. Thrombospondin, fibronectin, and vitronectin showed distinct localization patterns within Bone tissue. TSP was found mainly in osteoid and the periosteum; VN appeared to be present mainly in mature Bone matrix. FN was present in the periosteum as well as within both mature and immature Bone matrix. Using a panel of antiintegrin antibodies we found that Bone Cells in vivo and in vitro express alpha 4, alpha v, alpha 5 beta 1, alpha v beta 3, and beta 3/beta 5 integrins, and these receptors are for the most part expressed on all Bone Cells at different stages of maturation with quantitative rather than qualitative variations, with the exception of alpha 4, which is expressed mainly by osteoblasts. Cell Attachment assays were performed using primary human Cells of the osteoblastic lineage under serum-free conditions. COLL I, TSP, VN, FN, OPN, and BSP promoted Bone Cell Attachment in a dose-dependent manner and were equivalent in action when used in equimolar concentrations. In the presence of GRGDS peptide in the medium, the adhesion to BSP, OPN, and VN was almost completely blocked (10, 10, and 15% of control, respectively), and Attachment to FN, COLL I, and TSP was only slightly decreased (80, 75, and 55%, respectively). These results suggest that human Bone Cells may use RGD-independent mechanisms for Attachment to the latter glycoproteins.

Kevin E. Healy - One of the best experts on this subject based on the ideXlab platform.

  • A probabilistic approach to measure the strength of Bone Cell adhesion to chemically modified surfaces
    Annals of Biomedical Engineering, 1997
    Co-Authors: Alireza Rezania, Carson H. Thomas, Kevin E. Healy
    Abstract:

    Patterned surfaces with alternating regions of amino silanes [ N -(2-aminoethyl)-3-aminopropyl-trimethoxysilane (EDS)] and alkyl silanes [dimethyldichlorosilane (DMS)] have been used to alter the kinetics of spatial distribution of Cells in vitro . In particular, we have previously observed the preferential spatial distribution of Bone Cells on the EDS regions of EDS/DMS patterned surfaces (10). In this study, we examined whether the mechanism of spatial distribution of Cells on the EDS regions was adhesion mediated. Homogeneous layers of EDS and DMS were immobilized on quartz substrates and characterized by contact angle, X-ray photoelectron spectroscopy, and spectroscopic ellipsometry. The strength of Bone Cell Attachment to the modified substrates was examined using a radial flow apparatus, within either 20 min or 2 hr of Cell incubation in the presence of serum. A Weibull distribution was chosen to characterize the strength of Cell-substratum adhesion. Within 20 min of Cell exposure, the strength of adhesion was significantly larger on EDS and clean surfaces, compared with DMS surfaces ( p

  • A probabilistic approach to measure the strength of Bone Cell adhesion to chemically modified surfaces
    Annals of Biomedical Engineering, 1997
    Co-Authors: Alireza Rezania, Carson H. Thomas, Kevin E. Healy
    Abstract:

    Patterned surfaces with alternating regions of amino silanes [N-(2-aminoethyl)-3-aminopropyl-trimethoxysilane (EDS)] and alkyl silanes [dimethyldichlorosilane (DMS)] have been used to alter the kinetics of spatial distribution of Cells in vitro. In particular, we have previously observed the preferential spatial distribution of Bone Cells on the EDS regions of EDS/ DMS patterned surfaces (10). In this study, we examined whether the mechanism of spatial distribution of Cells on the EDS regions was adhesion mediated. Homogeneous layers of EDS and DMS were immobilized on quartz substrates and characterized by contact angle. X-ray photoelectron spectroscopy, and spectroscopic ellipsometry. The strength of Bone Cell Attachment to the modified substrates was examined using a radial flow apparatus, within either 20 min or 2 hr of Cell incubation in the presence of serum. A Weibull distribution was chosen to characterize the strength of Cell-substratum adhesion. Within 20 min of Cell exposure, the strength of adhesion was significantly larger on EDS and clean surfaces, compared with DMS surfaces (p < 0.001). Within 2 hr of Cell incubation, there was no statistical difference between the strength of Cell adhesion to EDS, DMS, and clean surfaces. The results of this study suggest that the surface chemistry mediates adhesion-based spatial Cell arrangement through a layer of adsorbed serum proteins.

Wojciech J Grzesik - One of the best experts on this subject based on the ideXlab platform.

  • Bone matrix rgd glycoproteins immunolocalization and interaction with human primary osteoblastic Bone Cells in vitro
    Journal of Bone and Mineral Research, 2009
    Co-Authors: Wojciech J Grzesik, Pamela Gehron Robey
    Abstract:

    The interaction of Cells with extraCellular matrix is essential for their anchorage, proliferation, migration, and differentiation. In Bone matrix there are multiple glycoproteins that contain the integrin-binding RGD sequence: fibronectin (FN), thrombospondin (TSP), osteopontin (OPN), Bone sialoprotein (BSP), type I collagen (COLL I), and vitronectin (VN). In this study, the localization of TSP, FN, VN, and several integrins within developing human long Bone using immunohistochemical methods was examined, as was the effect of all Bone RGD proteins on the adhesion of human osteoblastic Cells. Thrombospondin, fibronectin, and vitronectin showed distinct localization patterns within Bone tissue. TSP was found mainly in osteoid and the periosteum; VN appeared to be present mainly in mature Bone matrix. FN was present in the periosteum as well as within both mature and immature Bone matrix. Using a panel of antiintegrin antibodies we found that Bone Cells in vivo and in vitro express α4, αv, α5β1, αvβ3, and β3/β5 integrins, and these receptors are for the most part expressed on all Bone Cells at different stages of maturation with quantitative rather than qualitative variations, with the exception of α4, which is expressed mainly by osteoblasts. Cell Attachment assays were performed using primary human Cells of the osteoblastic lineage under serum-free conditions. COLL I, TSP, VN, FN, OPN, and BSP promoted Bone Cell Attachment in a dose-dependent manner and were equivalent in action when used in equimolar concentrations. In the presence of GRGDS peptide in the medium, the adhesion to BSP, OPN, and VN was almost completely blocked (10, 10, and 15% of control, respectively), and Attachment to FN, COLL I, and TSP was only slightly decreased (80, 75, and 55%, respectively). These results suggest that human Bone Cells may use RGD-independent mechanisms for Attachment to the latter glycoproteins.

  • Bone matrix rgd glycoproteins immunolocalization and interaction with human primary osteoblastic Bone Cells in vitro
    Journal of Bone and Mineral Research, 2009
    Co-Authors: Wojciech J Grzesik, Pamela Gehron Robey
    Abstract:

    The interaction of Cells with extraCellular matrix is essential for their anchorage, proliferation, migration, and differentiation. In Bone matrix there are multiple glycoproteins that contain the integrin-binding RGD sequence: fibronectin (FN), thrombospondin (TSP), osteopontin (OPN), Bone sialoprotein (BSP), type I collagen (COLL I), and vitronectin (VN). In this study, the localization of TSP, FN, VN, and several integrins within developing human long Bone using immunohistochemical methods was examined, as was the effect of all Bone RGD proteins on the adhesion of human osteoblastic Cells. Thrombospondin, fibronectin, and vitronectin showed distinct localization patterns within Bone tissue. TSP was found mainly in osteoid and the periosteum; VN appeared to be present mainly in mature Bone matrix. FN was present in the periosteum as well as within both mature and immature Bone matrix. Using a panel of antiintegrin antibodies we found that Bone Cells in vivo and in vitro express alpha 4, alpha v, alpha 5 beta 1, alpha v beta 3, and beta 3/beta 5 integrins, and these receptors are for the most part expressed on all Bone Cells at different stages of maturation with quantitative rather than qualitative variations, with the exception of alpha 4, which is expressed mainly by osteoblasts. Cell Attachment assays were performed using primary human Cells of the osteoblastic lineage under serum-free conditions. COLL I, TSP, VN, FN, OPN, and BSP promoted Bone Cell Attachment in a dose-dependent manner and were equivalent in action when used in equimolar concentrations. In the presence of GRGDS peptide in the medium, the adhesion to BSP, OPN, and VN was almost completely blocked (10, 10, and 15% of control, respectively), and Attachment to FN, COLL I, and TSP was only slightly decreased (80, 75, and 55%, respectively). These results suggest that human Bone Cells may use RGD-independent mechanisms for Attachment to the latter glycoproteins.

Alireza Rezania - One of the best experts on this subject based on the ideXlab platform.

  • A probabilistic approach to measure the strength of Bone Cell adhesion to chemically modified surfaces
    Annals of Biomedical Engineering, 1997
    Co-Authors: Alireza Rezania, Carson H. Thomas, Kevin E. Healy
    Abstract:

    Patterned surfaces with alternating regions of amino silanes [ N -(2-aminoethyl)-3-aminopropyl-trimethoxysilane (EDS)] and alkyl silanes [dimethyldichlorosilane (DMS)] have been used to alter the kinetics of spatial distribution of Cells in vitro . In particular, we have previously observed the preferential spatial distribution of Bone Cells on the EDS regions of EDS/DMS patterned surfaces (10). In this study, we examined whether the mechanism of spatial distribution of Cells on the EDS regions was adhesion mediated. Homogeneous layers of EDS and DMS were immobilized on quartz substrates and characterized by contact angle, X-ray photoelectron spectroscopy, and spectroscopic ellipsometry. The strength of Bone Cell Attachment to the modified substrates was examined using a radial flow apparatus, within either 20 min or 2 hr of Cell incubation in the presence of serum. A Weibull distribution was chosen to characterize the strength of Cell-substratum adhesion. Within 20 min of Cell exposure, the strength of adhesion was significantly larger on EDS and clean surfaces, compared with DMS surfaces ( p

  • A probabilistic approach to measure the strength of Bone Cell adhesion to chemically modified surfaces
    Annals of Biomedical Engineering, 1997
    Co-Authors: Alireza Rezania, Carson H. Thomas, Kevin E. Healy
    Abstract:

    Patterned surfaces with alternating regions of amino silanes [N-(2-aminoethyl)-3-aminopropyl-trimethoxysilane (EDS)] and alkyl silanes [dimethyldichlorosilane (DMS)] have been used to alter the kinetics of spatial distribution of Cells in vitro. In particular, we have previously observed the preferential spatial distribution of Bone Cells on the EDS regions of EDS/ DMS patterned surfaces (10). In this study, we examined whether the mechanism of spatial distribution of Cells on the EDS regions was adhesion mediated. Homogeneous layers of EDS and DMS were immobilized on quartz substrates and characterized by contact angle. X-ray photoelectron spectroscopy, and spectroscopic ellipsometry. The strength of Bone Cell Attachment to the modified substrates was examined using a radial flow apparatus, within either 20 min or 2 hr of Cell incubation in the presence of serum. A Weibull distribution was chosen to characterize the strength of Cell-substratum adhesion. Within 20 min of Cell exposure, the strength of adhesion was significantly larger on EDS and clean surfaces, compared with DMS surfaces (p < 0.001). Within 2 hr of Cell incubation, there was no statistical difference between the strength of Cell adhesion to EDS, DMS, and clean surfaces. The results of this study suggest that the surface chemistry mediates adhesion-based spatial Cell arrangement through a layer of adsorbed serum proteins.

Jeffrey O Hollinger - One of the best experts on this subject based on the ideXlab platform.

  • porous polymer scaffolds surface modified with arginine glycine aspartic acid enhance Bone Cell Attachment and differentiation in vitro
    Journal of Biomedical Materials Research Part A, 2003
    Co-Authors: Shelley R Winn, Ian Krajbich, Jeffrey O Hollinger
    Abstract:

    This study was designed to determine if the surface modification of porous poly(lactic acid) (PLA) scaffolds would enhance osteogenic precursor Cell (OPC) Attachment, growth, and differentiation. A covalently grafted amino group (−NH2), poly(L-lysine) (PLL), and the peptide arginine-glycine-aspartic acid (RGD) were selected for the evaluation. The hypothesis was that surface modification would have a positive impact on Cell–substratum interactions. The experiment was performed by OPC Cells being placed on PLA films and scaffolds modified with NH2, PLL, or RGD in tissue culture media. OPC Attachment to PLA films was assessed after 24 h of incubation. The growth and differentiation of the adherent OPCs on porous PLA scaffolds were assessed after 14 and 28 days for alkaline phosphatase (APase) activity and calcium levels, both of which increase as OPCs differentiate into mature Bone Cells. All assays were accomplished in triplicate, and data were tested with post hoc orthogonal contrasts (i.e., Fisher's least significant difference) at p ≤ 0.05. The PLA film surface-modified with RGD showed better OPC Cell Attachment than the other films. The Cells on the PLA scaffolds surface-modified with RGD also exhibited an increase in APase activity and calcium levels in comparison with those on other scaffolds. This difference was apparent at both time intervals and was especially evident in the tissue culture media containing an osteogenic supplement. The results of this study indicate that modifying the surface of PLA polymer scaffolds with RGD enhances Bone Cell Attachment and differentiation and may improve their ability to regenerate Bone tissue more efficiently in wound models. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 64A: 583–590, 2003