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Full-Text Articles in Engineering
Image Analysis Of Primary Bone-Derived Cells On Different Polystyrene Surfaces, R. M. Shelton, G. Landini
Image Analysis Of Primary Bone-Derived Cells On Different Polystyrene Surfaces, R. M. Shelton, G. Landini
Cells and Materials
The aim of the present study was to examine whether two different cell populations could be discerned using image analysis of a variety of morphological parameters on bacteriological and tissue culture polystyrene surfaces. Rat periosteal and osteoblast cultures were established on both polystyrene petri dishes and examined using phase contrast microscopy after one and two weeks before capturing digital images which were stored on a personal computer. The digital images were processed to identify the cell margins or perimeter, from which seven different morphological parameters were calculated using a program developed (by GL) for both the cell populations on the …
Gap Junctional Intercellular Communication In Bone, Henry J. Donahue, Monique A. Vander Molen, Clare E. Yellowley, Zhongyong Li
Gap Junctional Intercellular Communication In Bone, Henry J. Donahue, Monique A. Vander Molen, Clare E. Yellowley, Zhongyong Li
Cells and Materials
Gap junctional intercellular communication has been demonstrated in bone cells and may contribute to the mechanism by which osteoblasts integrate and amplify extracellular signals, both chemical (hormonal) and biophysical (electrical and mechanical). Connexin 43 (Cx43) is the predominant gap junction protein expressed by bone cells. Experiments with osteoblastic cells in which Cx43 expression was diminished by antisense transfection demonstrate that cell-to-cell coupling in osteoblastic ROS 17/2.8 cells is via gap junctions composed of Cx43. Cellular networks of these coupling deficient clones are dramatically less responsive to parathyroid hormone (PTH) suggesting that coupling contributes to hormonal responsiveness. Furthermore, PTH per se …
Analysis Of The Bony Interface With Various Types Of Hydroxyapatite In Vitro, J. D. De Bruijn, J. S. Flach, K. De Groot, C. A. Van Blitterswijk, J. E. Davies
Analysis Of The Bony Interface With Various Types Of Hydroxyapatite In Vitro, J. D. De Bruijn, J. S. Flach, K. De Groot, C. A. Van Blitterswijk, J. E. Davies
Cells and Materials
Rat bone marrow cells, capable of forming bonelike tissue, were cultured on three types of plasma sprayed hydroxyapatite that differed in degree of crystallinity from 15%, 43% to 69%. The interface between the mineralized extracellular matrix and the hydroxyapatite was studied with scanning and transmission electron microscopy. At the onset of bone formation, calcium and phosphorous-rich afibrillar globules, with a diameter varying from 0.2 to 0.8 μm, were produced and deposited onto the different substrata. These globules subsequently fused to form a homogeneous layer to which collagen fibres became anchored. Individual globules could be distinguished on the non-degrading 69 % …
Ultrastructural, Cytochemical, And Immunocytochemical Studies On Bone And Its Interfaces, M. D. Mckee, A. Nanci
Ultrastructural, Cytochemical, And Immunocytochemical Studies On Bone And Its Interfaces, M. D. Mckee, A. Nanci
Cells and Materials
Bone cells possess the ability to synthesize, secrete and direct the assembly and maintenance of extracellular matrix to form a functionally rigid and/or weight-bearing mineralized tissue complex, the skeleton. The skeleton not only supports and protects the organs and tissues of the body, but also acts as a mineral ion reservoir for maintaining systemic calcium balance (calcium homeostasis). The remarkable biological precision necessary for the formation, turnover and constant adaptation of bone to external mechanical forces is a dynamic process requiring a coordinated cellular effort relying on a variety of cell-cell and cell-matrix/mineral interactions. Indeed, cell-matrix interfaces found in a …
Influence Of Crystal Structure On The Establishment Of The Bone-Calcium Phosphate Interface In Vitro, J. D. De Bruijn, C. P. A. T. Klein, K. De Groot, C. A. Van Blitterswijk
Influence Of Crystal Structure On The Establishment Of The Bone-Calcium Phosphate Interface In Vitro, J. D. De Bruijn, C. P. A. T. Klein, K. De Groot, C. A. Van Blitterswijk
Cells and Materials
An in vitro rat bone marrow cell system was used to examine the interfacial ultrastructure established between various calcium phosphates and mineralized tissue. The investigated calcium phosphates comprised hydroxyapatite (HA), fluorapatite (FA), tricalcium phosphate (TCP), tetracalcium phosphate (TECP) and magnesium whitlockite (MWL). Both scanning and transmission electron microscopy were used to examine the elaborated interface. The time in which a mineralized extracellular matrix was formed on the various materials differed from 2 weeks on HA, TCP and TECP, to 8 weeks on FA. It was only occasionally observed in some areas on MWL, which might have been due to aluminum …
The Role Of Implant Surface Geometry On Mineralization In Vivo And In Vitro; A Transmission And Scanning Electron Microscopic Study, B. Chehroudi, J. Ratkay, D. M. Brunette
The Role Of Implant Surface Geometry On Mineralization In Vivo And In Vitro; A Transmission And Scanning Electron Microscopic Study, B. Chehroudi, J. Ratkay, D. M. Brunette
Cells and Materials
The purpose of th.is study was to examine the effect of substratum surface topography on bone formation in vivo and in vitro. Precise control over substratum topography was achieved using micromachining, a technique developed from the fabrication of microelectronic components. In the in vivo studies, titanium-coated epoxy replicas of micromachined surfaces were implanted subcutaneously in the parietal area of rats. After 6 weeks, bone-like tissue was found adjacent to some micromachined surfaces. Detailed observation of this tissue with the transmission electron microscope revealed osteoblast/osteocyte-like cells and a fully or partially mineralized collagenous matrix. Mineralized matrix and collagen bundles were …
Deposition And Resorption Of Calcified Matrix In Vitro By Rat Marrow Cells, J. E. Davies, R. Chernecky, B. Lowenberg, A. Shiga
Deposition And Resorption Of Calcified Matrix In Vitro By Rat Marrow Cells, J. E. Davies, R. Chernecky, B. Lowenberg, A. Shiga
Cells and Materials
Rat bone marrow derived cells were cultured using a-Minimal Essential Medium supplemented with antibiotics, ascorbic acid and !3-glycerphosphate in the presence of 10-8M dexamethasone, on polystyrene and hydrophilic fluorocarbon substrata for periods of 2 - 4 weeks. During this time, a large yield of bone nodules was achieved and the elaborated tissue was examined by both scanning and transmission electron microscopy. The matrix produced by the cells contacting the underlying substratum was an afibrillar, globular, calcified material which formed a layer approximately 0.5μm thick. The calcium and phosphorus content of this material was confirmed by energy dispersive X-ray dot mapping …
Ultrastructural Study Of Bone Formation On Synthetic Hydroxyapatite In Osteoblast Cultures, J. M. Sautier, J. R. Nefussi, N. Forest
Ultrastructural Study Of Bone Formation On Synthetic Hydroxyapatite In Osteoblast Cultures, J. M. Sautier, J. R. Nefussi, N. Forest
Cells and Materials
Collagenase isolated rat calvaria cells forming a mineralized matrix in vitro were cultured in the presence of synthetic hydroxyapatite. Interactions between bone cells and hydroxyapatite biomaterial were followed by transmission electron microscopy. The appearance of a granular, collagen free, electron-dense layer at the periphery of the material was noted initially. Progressively, an amorphous, granular material formed and extended between the hydroxyapatite aggregates. Osteoblastic cells then synthesized an osteoid matrix which mineralized on the first formed granular collagen free layer, following a classical pattern of calcification . Demineralization of ultrathin sections confirmed the presence of this interface between the material and …