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Biomedical Engineering and Bioengineering Commons™
Open Access. Powered by Scholars. Published by Universities.®
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- Scanning electron microscopy (34)
- Bone (18)
- Biomaterials (17)
- Hydroxyapatite (13)
- Microstructure (13)
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- Transmission electron microscopy (11)
- In vitro (10)
- Interface (10)
- Biocompatibility (9)
- Calcium phosphate (8)
- Osteoblast (8)
- Cell culture (7)
- Dental alloy (7)
- Extracellular matrix (7)
- Mineralization (7)
- Biomaterial (6)
- Calcification (6)
- Osteoclast (6)
- Palladium (6)
- Ultrastructure (6)
- Collagen (5)
- Eutectic (5)
- Image analysis (5)
- Osteoclasts (5)
- Titanium (5)
- X-ray microanalysis (5)
- Adhesion (4)
- Backscattered electron imaging (4)
- Bone-bonding (4)
- Crystallinity (4)
Articles 31 - 60 of 166
Full-Text Articles in Biomedical Engineering and Bioengineering
Detachment Of Human Endothelial Cells Under Flow From Wettability Gradient Surfaces With Different Functional Groups, T. G. Ruardy, H. E. Moorlag, J. M. Schakenraad, H. C. Van Der Mei, H. J. Busscher
Detachment Of Human Endothelial Cells Under Flow From Wettability Gradient Surfaces With Different Functional Groups, T. G. Ruardy, H. E. Moorlag, J. M. Schakenraad, H. C. Van Der Mei, H. J. Busscher
Cells and Materials
In this study, the position bound adhesion, spreading and detachment under flow of human umbilical cord endothelial cells (HUVEC) was studied on a dichlorodimethylsilane (DDS), dimethylocta-decylchlorosilane (DOCS) and tridecafluor-1,1,2,2-tetrahydrooctyl-1-dimethylchlorosilane (TFCS) wettability gradient on glass. Gradient surfaces were prepared by the diffusion method and characterized by the Wilhelmy plate technique for their wettability and by X-ray photoelectron spectroscopy (XPS) for their chemical composition. Quantitative analysis of the cellular response on the wettability gradient surfaces showed that the position bound cellular response was influenced by wettability for each type of gradient in a different way. On DDS-wettability gradients, cells withstood flow best …
Biofilms In Dental Unit Waterlines: Ultrastructural And Cytochemical Analysis, J. Barbeau, C. Avezard, E. Faucher, S. Zalzal, A. P. Prévost
Biofilms In Dental Unit Waterlines: Ultrastructural And Cytochemical Analysis, J. Barbeau, C. Avezard, E. Faucher, S. Zalzal, A. P. Prévost
Cells and Materials
Dental unit waterlines are heavily colonized by bacteria which contaminate the water used to perform intra-oral, and sometimes invasive, procedures. There is little information on the nature of the biofilm colonizing the flexible plastic tubing used to supply water to the different handpieces. We have therefore undertaken quantitative microbial analysis and ultrastructural studies of these biofilms by direct counting with the epifluorescent filter technique and by transmission and scanning electron microscopy after staining with ruthenium red and periodic acid-thiosemicarbazide-silver proteinate to visualize the composition and the distribution of exopolysaccharides and intracellular polysaccharides. The biofilm was revealed as a non-uniform structure …
Validation Of Energy Dispersive X-Ray Spectrometry As A Method To Standardize Backscattered Electron Images Of Bone, E. G. Vajda, R. D. Bloebaum, J. G. Skedros
Validation Of Energy Dispersive X-Ray Spectrometry As A Method To Standardize Backscattered Electron Images Of Bone, E. G. Vajda, R. D. Bloebaum, J. G. Skedros
Cells and Materials
The use of backscattered electron (BSE) imaging as a tool for the qualitative measurement of mineral content in bone has been well documented. The challenge still remains to develop BSE imaging as a tool for quantitative mineral content analysis in bone. The limiting factor has been the ability to standardize the BSE signal within and between laboratories. Energy dispersive x-ray spectrometry (EDX) has been proposed as a method to standardize the BSE operating environment. The goal of this study is to investigate the relationship between EDX-determined wt.% Ca measurements and BSE graylevels. A comparison with traditional ash content measurements will …
Laboratory Growth Systems In Biofilm Research, Julian W. T. Wimpenny
Laboratory Growth Systems In Biofilm Research, Julian W. T. Wimpenny
Cells and Materials
The huge variety of ecosystems that we collectively refer to as "biofilm" is reflected by the numerous different systems available to grow them in the laboratory. The relationship between in situ systems, microcosms and laboratory models is defined and discussed. The first two represent holistic approaches designed to assess the structure and function of particular biofilms: the last is analytical and reductionist, aiming to isolate specific functions of biofilms in order to understand properties that can apply to biofilm in general. Properties of a model can be completely understood whilst this is unlikely with natural ecosystems because of the possibility …
Initial Biodeterioration Of Silicone Rubber By C. Albicans And C. Aropicalis Strains Isolated From Voice Prostheses, H. C. Van Der Mei, B. Van De Belt-Gritter, F. Dijk, H. J. Busscher
Initial Biodeterioration Of Silicone Rubber By C. Albicans And C. Aropicalis Strains Isolated From Voice Prostheses, H. C. Van Der Mei, B. Van De Belt-Gritter, F. Dijk, H. J. Busscher
Cells and Materials
Silicone rubber voice prostheses m patients after total laryngectomy become rapidly colonized by a biofilm, consisting of yeasts and bacteria. An especially troublesome feature of these biofilms is the ingrowth into the silicone rubber by colonizing yeasts. Microcolonies of ingrowing yeasts have been frequently observed on explanted voice prostheses after 3-4 months use. Incubation of silicone rubber samples in a modified Robbins device with a culture of Candida tropicalis, isolated from a Groningen button voice prosthesis, while passing the yeasts through a cycle of feasts (7 days) and famine (also 7 days) demonstrated, by electron microscopy, the onset of the …
Investigation Of Bone And Calcium Phosphate Coatings And Crystallinity Determination Using Raman Microspectroscopy, C. J. De Grauw, J. D. De Bruijn, C. Otto, J. Greve
Investigation Of Bone And Calcium Phosphate Coatings And Crystallinity Determination Using Raman Microspectroscopy, C. J. De Grauw, J. D. De Bruijn, C. Otto, J. Greve
Cells and Materials
Conventional spontaneous Raman micro-spectroscopy was used for the investigation of bone and calcium phosphate coatings on bone-implant surfaces. Chemical and structural changes at the bone-coating interface could be monitored on a microscopic scale. It was shown that the crystallinity did not vary within the crystalline apatite and amorphous calcium phosphate coatings, while the density within each coating did vary. Different degrees of crystallinity in coatings were investigated for a series of plasma-sprayed apatite coatings. It is concluded that Raman microspectroscopy is an easy non-destructive way to obtain information about the apatite structure and the degree of crystallinity.
Effects Of Solidification Conditions And Heat Treatment On The Microstructure And Vickers Hardness Of Pd-Cu-Ga Dental Alloys, William A. Brantley, Zhuo Cai, Stanley G. Vermilyea, Efstratios Papazoglou, John C. Mitchell, Alan B. Carr
Effects Of Solidification Conditions And Heat Treatment On The Microstructure And Vickers Hardness Of Pd-Cu-Ga Dental Alloys, William A. Brantley, Zhuo Cai, Stanley G. Vermilyea, Efstratios Papazoglou, John C. Mitchell, Alan B. Carr
Cells and Materials
Two representative Pd-Cu-Ga dental alloys, one with a dendritic as-cast microstructure containing a eutectic interdendritic constituent and the other with an equiaxed fine-grained as-cast microstructure containing a near-surface eutectic constituent, have been subjected to rapid quenching following casting, in addition to the conventional bench cooling recommended by the manufacturers. The quenched alloys were subsequently heat treated at temperatures of 1200°, 1500° and 1800 op that span the range of the firing cycles for dental porcelain. Scanning electron microscopic examination showed that the lamellar eutectic constituents normally present in the microstructures of the as-cast and bench-cooled alloys persisted when the alloys …
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 …
Time Course Of Recruitment, Pit Formation And Apoptosis Of Osteoclast Populations On Dentin In Vitro, Jihyun Kang, Rigoberto Cornejo, Kevin J. Hirokawa, Susan M. Digiorgio, Darlene F. Howard, Susan F. Silverton
Time Course Of Recruitment, Pit Formation And Apoptosis Of Osteoclast Populations On Dentin In Vitro, Jihyun Kang, Rigoberto Cornejo, Kevin J. Hirokawa, Susan M. Digiorgio, Darlene F. Howard, Susan F. Silverton
Cells and Materials
The resorptive capacity of osteoclasts in vitro has been used as an indicator of bone resorption. However, the kinetics of osteoclast development and senescence is not well understood. It has been noted that mononuclear precursors migrate to calcified substrate and after multi-nucleation become competent bone resorbing cells. Osteoclasts, once finished a wave of resorption, become senescent. In order to determine the survival characteristics of osteoclast populations involved in calcified tissue destruction, we have investigated the time course of the recruitment to dentin and apoptosis of osteoclasts. We have established the linkage between these measurements and the time course of the …
Biodegradation Of A Nano-Hydroxyapatite/Collagen Composite By Peritoneal Monocyte-Macrophages, F. Z. Cui, C. Du, X. W. Su, X. D. Zhu, N. M. Zhao
Biodegradation Of A Nano-Hydroxyapatite/Collagen Composite By Peritoneal Monocyte-Macrophages, F. Z. Cui, C. Du, X. W. Su, X. D. Zhu, N. M. Zhao
Cells and Materials
A nano-hydroxyapatite/collagen composite was prepared by precipitation of hydroxyapatite from an aqueous solution onto collagen. Mouse peritoneal macrophages were used to investigate the in vitro biodegradation of the composite. The results showed the mechanism of phagocytosis and extracellular degradation process. The cells that belong to the mononuclear phagocyte system showed some morphological characteristics similar to those of osteoclasts and made pits on the composite surface. The local modification of the material surface by the cell was another phenomenon distinguishable from the degradation process. The degradation and modification made the material porous with a widely varying Ca/P ratio.
The Role Of Surface Characteristics In The Initial Adhesion Of Human Bone-Derived Cells On Ceramics, H. Zreiqat, O. C. Standard, T. Gengenbach, J. G. Steele, C. R. Howlett
The Role Of Surface Characteristics In The Initial Adhesion Of Human Bone-Derived Cells On Ceramics, H. Zreiqat, O. C. Standard, T. Gengenbach, J. G. Steele, C. R. Howlett
Cells and Materials
The tissue/biomaterial interactions of three biomaterials of potential use in bone implants were studied in vitro. The mechanism of cell adherence to various ceramic substrata has been investigated by measurement of short term (90 minutes) cell attachment and spreading rate. We have determined the effect of two serum glycoproteins, fibronectin and vitronectin, on the adhesion of human bone derived cells (HBD-cells) cultured on three different types of ceramics {alumina (Al2O3), hydroxyapatite (HAP) and yttria-doped tetragonal zirconia polycrystal (Y-TZP)} . The attachment of HBD-cells to alumina and hydroxyapatite was approximately 60% of that to Y-TZP. Furthermore, …
The Influence Of A Fibrin-Coating Inside A Biodegradable Poly(Dl-Lactide-Ε-Caprolactone) Nerve Guide On Peripheral Nerve Regeneration, W. F. A. Den Dunnen, J. M. Schakenraad, B. Van Der Lei, A. J. Pennings, P. H. Robinson
The Influence Of A Fibrin-Coating Inside A Biodegradable Poly(Dl-Lactide-Ε-Caprolactone) Nerve Guide On Peripheral Nerve Regeneration, W. F. A. Den Dunnen, J. M. Schakenraad, B. Van Der Lei, A. J. Pennings, P. H. Robinson
Cells and Materials
The aim of this study was to evaluate the effect of a fibrin-coating on the inner surface of a biodegradable poly(DL-lactide-E-caprolactone) nerve guide on the speed and quality of the nerve regeneration. The nerve regeneration and orientation of the nerve fibers, as well as the fibrous tissue formation were evaluated. On the short term, nerve regeneration was slightly faster in the non-coated nerve guide. After longer implantation periods (≥ 4 weeks), nerve regeneration in the fibrin-coated nerve guides was characterized by a severe inflammatory response with large numbers of macrophages and polymorphonuclear cells (PMN's). This study clearly demonstrates that nerve …
Stability Of Liposomes Prepared From Archaeobacterical Lipids And Phosphatidylcholine Mixtures, G. D. Sprott, C. J. Dicaire, L. P. Fleming, G. B. Patel
Stability Of Liposomes Prepared From Archaeobacterical Lipids And Phosphatidylcholine Mixtures, G. D. Sprott, C. J. Dicaire, L. P. Fleming, G. B. Patel
Cells and Materials
In vitro stabilities of liposomes prepared from the total polar lipids (TPL) of various species of Archaeobacteria were compared with those made from egg phosphatidylcholine (EPC) and from mixtures of TPLIEPC. Stability was monitored by measuring the extent of leakage of entrapped dyes. Liposomes prepared from exclusively archaeobacteriallipids (coined archaeosomes), particularly those containing the bilayer spanning tetraether lipids, were generally stable to conditions such as storage at 37°C for greater than 7 days, exposure to phospholipase A2, incubation with serum, and, to some extent, exposure to bile salts. In contrast, EPC liposomes were generally unstable to these conditions, …
Biofilm Mediated Calculus Formation In The Urinary Tract, Robert J. C. Mclean, David J. Stickler, J. Curtis Nickel
Biofilm Mediated Calculus Formation In The Urinary Tract, Robert J. C. Mclean, David J. Stickler, J. Curtis Nickel
Cells and Materials
Mineralization and subsequent calculus formation is a common complication of biofilm infections. In the urinary tract, these infected calculi often arise from infections by urease-producing bacteria. Ammonia, liberated by bacterial urease activity, increases urine pH, resulting in the precipitation of Ca and Mg as carbonateapatite {Ca10(PO4,CO3)6(OH,CO3)2} and struvite (NH4MgP04·6H2O). These minerals become entrapped in the organic matrix which surrounds the infecting organisms and ultimately grow into mature calculi. When the causative organisms grow on urinary catheters and stents, the resulting mineralization can …
Heterogeneity Of Natural Biofilm Communities, J. R. Lawrence, D. R. Korber, G. M. Wolfaardt
Heterogeneity Of Natural Biofilm Communities, J. R. Lawrence, D. R. Korber, G. M. Wolfaardt
Cells and Materials
Scanning confocal laser microscopy (SCLM) studies have shown that microbial biofilms consist of a spatially heterogeneous arrangement of bacterial cells, biogenic extracellular material, and void space. Biofilm architecture is dominated by the presence of cell aggregates interspersed by channels, the arrangement of which varies for different hydrodynamic regimes, ages, species composition, or nutrient status. This organization may regulate the flux of nutrients and oxygen, creating chemical microenvironments (Eh, pH) facilitating the growth of aerobic heterotrophs and anaerobes. The presence of microenvironments has been confirmed using laser microscopy and environmentally sensitive fluorescent probes. In addition, changes in cell number and growth …
The Effect Of Vitronectin And Other Extracellular Matrix Molecules On Endothelial Expansion And Plasminogen Activation, P. Anne Underwood, Penny A. Bean
The Effect Of Vitronectin And Other Extracellular Matrix Molecules On Endothelial Expansion And Plasminogen Activation, P. Anne Underwood, Penny A. Bean
Cells and Materials
Endothelial recovery following procedures used to alleviate blood vessel occlusion is modulated by the local extracellular matrix upon which it has to migrate and proliferate. This extracellular material is derived from vessel wall cells, and plasma proteins which bind to the exposed surfaces. We have demonstrated that vitronectin adsorbs efficiently to tissue culture polystyrene in competition with other plasma proteins, which suggests that it may adsorb to biomaterial surfaces in vivo. We have compared the adhesion, migration and proliferation of human umbilical artery endothelial cells on surface-coated vitronectin, with other extracellular matrix molecules encountered in this environment, namely fibronectin, …
Collagen Fibres Are Not Required For Initial Matrix Mineralization By Bone Cells, M. M. Hosseini, S. A. F. Peel, J. E. Davies
Collagen Fibres Are Not Required For Initial Matrix Mineralization By Bone Cells, M. M. Hosseini, S. A. F. Peel, J. E. Davies
Cells and Materials
Passaged primary cultures of young adult rat bone marrow cells were maintained in medium containing combinations of the supplements dexamethasone, ascorbic acid and Na-ß-glycerophosphate. The cultures were examined by both light and scanning electron microscopy (with additional energy dispersive X-ray analysis). In cultures with fully supplemented medium, an extracellular matrix formed at the culture dish surface, beneath developing bone nodules; this matrix was mineralized but collagen-fibre free and corresponded to that which we have reported previously as the equivalent of the cement line in vivo. In selected samples this interfacial, cement line, matrix was analyzed by X-ray …
Perturbations Of Periosteel Bone During Healing: Effect Of Non-Weight Bearing, Helen E. Gruber, Mary E. Kirchen, John R. Sweeney, William E. Anderson, G. June Marshall
Perturbations Of Periosteel Bone During Healing: Effect Of Non-Weight Bearing, Helen E. Gruber, Mary E. Kirchen, John R. Sweeney, William E. Anderson, G. June Marshall
Cells and Materials
Weight bearing (WB) is an important factor influencing bone remodelling. The present study evaluates the effects of weight bearing and non-weight bearing (S) (achieved by tail suspension and hindlimb elevation) on the healing of a fibular osteotomy in adult male rats. After 9, 18 or 36 days under WB or S conditions, periosteum near the callus formed at the osteotomy site was compared to periosteum of the contralateral fibula (which did not receive an osteotomy) or to periosteum of fibula of control animals which did not receive an osteotomy. Data show that periosteal bone healing is sensitive to alterations in …
Letter To The Editor: Biocompatibility And Reactogenicity Of Materials: A Semantic And Logical Analysis Of Definitions And Their Practical Significance, Leonid I. Slutskii, Janis J. Vetra
Letter To The Editor: Biocompatibility And Reactogenicity Of Materials: A Semantic And Logical Analysis Of Definitions And Their Practical Significance, Leonid I. Slutskii, Janis J. Vetra
Cells and Materials
Any biomaterial implanted into a living body elicits a distinct local reaction. This reaction depends on the physical, physico-chemical and chemical properties of the material. The obvious term to designate this inherent property of a biomaterial to induce a local reaction is reactogenicity. Reactogenicity of a biomaterial is one of the main factors determining (together with other properties of the implanted device) the bio(non)compatibility of the implant. Such amplification of terminology which establishes differences between biocompatibility as a generalized characteristic of biomaterials in all their interrelations with the host's organism and the influences on local processes around implants, makes the …
A Composite Biomaterial: Poly 2 (Hydropoxyethyl) Methacrylate / Alkaline Phosphatase Initiates Mineralization In Vitro, R. Filmon, D. Chappard, J. P. Monthéard, M. F. Baslé
A Composite Biomaterial: Poly 2 (Hydropoxyethyl) Methacrylate / Alkaline Phosphatase Initiates Mineralization In Vitro, R. Filmon, D. Chappard, J. P. Monthéard, M. F. Baslé
Cells and Materials
Bone substitutes are nowadays largely used in orthopedic surgery but they lack osteoinductive properties. Poly (2-hydroxyethyl methacrylate) (pHEMA) has numerous biomedical applications. Alkaline phosphatase (AlkP), an ectoenzyme elaborated by osteoblasts, initiates bone mineralization by hydrolyzing organic phosphates before calcium-phosphorus deposition. We have immobilized AlkP in pHEMA in a copolymerization technic. Histochemical study revealed that AlkP has retained its biological activity . Image analysis of sections using a tessellation method showed a lognormal distribution of the area of tessels around AlkP particles thus confirming an homogeneous distribution of the enzyme in the polymer. Pellets of pHEMA and pHEMA + AlkP were …
Application Of Confocal Laser Scanning Microscopy To Cytocompatibility Testing Of Potential Orthopaedic Materials In Immortalised Osteoblast-Like Cell Lines, R. Macnair, R. Wilkinson, C. Macdonald, I. Goldie, D. B. Jones, M. H. Grant
Application Of Confocal Laser Scanning Microscopy To Cytocompatibility Testing Of Potential Orthopaedic Materials In Immortalised Osteoblast-Like Cell Lines, R. Macnair, R. Wilkinson, C. Macdonald, I. Goldie, D. B. Jones, M. H. Grant
Cells and Materials
Confocal laser scanning microscopy (CLSM) was used in conjunction with in vitro cell culture to investigate cellular interactions with orthopaedic biomaterials. Transfected rat and human osteoblasts were seeded on two potential isoelastic hip prosthesis materials, carbon fibre reinforced polyetheretherketone (PEEK) and epoxy. Titanium 318 alloy was employed as a control. Determination of the material surface contour, an important factor influencing cellular adhesion, proliferation and function, was performed using the industry standard Talysurf® and compared to analogous results obtained using the CLSM. The latter technique consistently gave higher values of material roughness but offers the advantage that it can be used …
Physical And Biological Evaluation Of Hydroxylapatite Films Formed On Ti6a14v Substrates By Excimer Laser Ablation, Tatjana Dostálová, Miroslav Jelínek, Lucie Himmlová, Vlasta Pesáková, Milan Adam
Physical And Biological Evaluation Of Hydroxylapatite Films Formed On Ti6a14v Substrates By Excimer Laser Ablation, Tatjana Dostálová, Miroslav Jelínek, Lucie Himmlová, Vlasta Pesáková, Milan Adam
Cells and Materials
Thin films of hydroxylapatite, about 500 nm, were formed on Ti6Al4V by excimer laser ablation. Ten different deposition conditions were used such as deposition atmosphere (vacuum, pure water vapor, mixture of Ar and water vapor), substrate temperature, target-substrate distance and energy density. Mechanical and physical analyses were carried out by Rutherford backscattering and particle induced X-ray emission; crystallinity of films was determined by X-ray diffraction, surface topography by scanning electron microscopy and adhesion by a scratch test. Biological evaluation of samples was also performed. The fibroblast proliferation test was used, morphological evaluation of macrophages was carried out, and the activity …
Albumin Affinity Biomaterial Surfaces, James R. Keogh, John W. Eaton
Albumin Affinity Biomaterial Surfaces, James R. Keogh, John W. Eaton
Cells and Materials
Recently, considerable progress has been made in designing biomaterial surfaces which possess enhanced albumin affinity. Two derivatization methods for producing albumin binding biomaterial surfaces, based on an albumin affinity dye, cibacron blue, have been developed. Both surface derivatization methods were found to enhance the binding of albumin to an implant grade polyetherurethane. Evaluations of the enhanced albumin affinity demonstrated the binding to be both selective and reversible. Surfaces having such enhanced albumin affinity were found to be minimally thrombogenic and to discourage the adhesion of bacteria which might otherwise cause device-centered infections. We conclude that albumin affinity surfaces, such as …
A Microstructural Investigation Of Calcium Hydroxyapatites Synthesized From Cahpo4•2h2o And Ca4(Po4)2o, Kevor S. Tenhuisen, Boyd A. Clark, Maria Klimkiewicz, Paul W. Brown
A Microstructural Investigation Of Calcium Hydroxyapatites Synthesized From Cahpo4•2h2o And Ca4(Po4)2o, Kevor S. Tenhuisen, Boyd A. Clark, Maria Klimkiewicz, Paul W. Brown
Cells and Materials
This investigation determined the effects of reaction temperature and bulk composition on the microstructural features of hydroxyapatites (HAp) synthesized from reaction between particulate CaHPO4·2H2O and Ca4(PO4)2O. These data were used in combination with previous work to further elucidate the mechanistic reaction path taken by these calcium phosphate cements. HAps having two different compositions (Ca/P = 1.50 and 1.67) were synthesized between 15.0 and 70.0°C. All reactions reached completion as indicated by X-ray diffraction. Single point nitrogen absorption was performed on all samples to determine specific surface areas. The HAp which …
Scanning Electron Microscopy Studies Of Ceramic Layers And Interfacial Regions For Calcium Phosphate-Coated Titanium Dental Implants, W. A. Brantley, E. Tufecki, J. C. Mitchell, D. W. Foreman, E. A. Mcglumphy
Scanning Electron Microscopy Studies Of Ceramic Layers And Interfacial Regions For Calcium Phosphate-Coated Titanium Dental Implants, W. A. Brantley, E. Tufecki, J. C. Mitchell, D. W. Foreman, E. A. Mcglumphy
Cells and Materials
The surface and cross-section characteristics of the plasma-sprayed calcium phosphate coatings, along with the microstructures and elemental compositions near the titanium alloy interface, were investigated by scanning electron microscopy for two different dental implants of proprietary compositions: Integra!® (Calcitek) and BioVent ® (Dentsply). Elemental concentrations (Ca, P, Ti, AI, and V) near the interfaces were obtained by X-ray energy-dispersive spectroscopy. Coating surfaces exhibited a splat deposition topography of greatly differing microstructural scale for the two implants, along with other features characteristic of the plasma-spraying process; cross-sections of the coatings revealed minimal porosity. Some interdiffusion of principally titanium and calcium was …
In Vitro Characterization Of Transforming Growth Factor-Ss1-Loaded Composites Of Biodegradable Polymer And Mesenchymal Cells, S. B. Nicoll, A. E. Denker, R. S. Tuan
In Vitro Characterization Of Transforming Growth Factor-Ss1-Loaded Composites Of Biodegradable Polymer And Mesenchymal Cells, S. B. Nicoll, A. E. Denker, R. S. Tuan
Cells and Materials
A porous, biodegradable polymer composite was fabricated from poly(L-lactic acid) (PLLA) using a solvent- casting particulate-leaching technique, and loaded with recombinant human transforming growth factor ß-1 (TGF-ß1). Tissue culture polystyrene (TCPS) and PLLA disks loaded with bovine serum albumin (BSA) served as controls. Polymer specimens were seeded at high cell density with C3H10T1/2 cells, a mouse embryonic cell line capable of differentiating into various connective tissue cell types. The polymer matrices degraded slowly in physiological saline over four weeks, with a sustained yet sporadic release of active TGF-ß1; a more controlled release of TGF-ß1 was observed in serum-containing culture medium …
Three-Dimensional Morphology And Platelet Adhesion On Pyrolytic Carbon Heart Valve Materials, S. L. Goodman, K. S. Tweden, R. M. Albrecht
Three-Dimensional Morphology And Platelet Adhesion On Pyrolytic Carbon Heart Valve Materials, S. L. Goodman, K. S. Tweden, R. M. Albrecht
Cells and Materials
Low-temperature isotropic pyrolytic carbon (LTIC) is the preferred material for mechanical heart valve prosthetics due to its durability and good thromboresistance, although thromboembolic complications remain a significant clinical problem. LTlC morphology has been previously studied using scanning (SEM) and transmission electron microscopy (TEM), and scanning tunneling microscopy (STM). However, these microscopies have limitations with imaging rough surfaces. In this study, LTIC valve leaflets from CarboMedics, Inc. and St. Jude Medical, Inc. were prepared and polished exactly as used in clinical prosthetics, and examined at magnifications up to macromolecular resolution using stereo-pair low-voltage SEM (LV -SEM). LV -SEM reveals that LTIC …
Adsorption Of Bovine Serum Albumin Onto Octacalcium Phosphate And Its Hydrolyzates, O. Suzuki, H. Yagishita, M. Yamazaki, T. Aoba
Adsorption Of Bovine Serum Albumin Onto Octacalcium Phosphate And Its Hydrolyzates, O. Suzuki, H. Yagishita, M. Yamazaki, T. Aoba
Cells and Materials
Octacalcium phosphate (OCP) has been advocated to be a precursor of biomineral s. Tn this report , we aimed at investigating OCP hydrolysis and the interaction of OCP and its hydrolyzates (apatitic products) with bovine serum albumin (BSA). A batch of synthetic OCP was allowed to hydrolyze either (a) in deionized water at 70°C or (b) in Tris buffer (pH 7.4) containing 2 ppm fluoride at 37°C. OCP hydrolysis was completed within reasonable experimental periods: after 48 hours at 70°C and after 10 days at 37°C in the presence of fluoride. The adsorption isotherms of BSA onto the original OCP …
Post-Operative Carbonate-Apatite Formation In Peo/Pbt Copolymers (Polyactive®), A. M. Radder, J. E. Davies, R. N. S. Sodhi, S. A. T. Van Der Meer, J. G. C. Wolke, C. A. Van Blitterswijk
Post-Operative Carbonate-Apatite Formation In Peo/Pbt Copolymers (Polyactive®), A. M. Radder, J. E. Davies, R. N. S. Sodhi, S. A. T. Van Der Meer, J. G. C. Wolke, C. A. Van Blitterswijk
Cells and Materials
Previous studies have stressed the importance of calcification of the polyethylene oxide (PEO) I polybutylene terephthalate (PBT) copolymer surface by establishing a direct relation with the occurrence of bone-bonding. Here, we characterized the morphology as well as the composition of this post-operative reaction product in PEOIPBT copolymers. X-ray · photoelectron spectroscopical results demonstrated the ability of PEOIPBT copolymers to rapidly adsorb calcium ions from fluids. After subcutaneous implantation in rats, it was shown that polymer calcification comprised plate-shaped crystals, whereas an electron-dense layer was frequently encountered at the interface. Cells with a characteristic morphology were directly apposed to abundantly calcified …
Bone Absorptiometry In Metabolic Bone Disease: Baseline Values And Long-Term Treatment With Calcitriol (Post-Menopausal Osteoporosis Versus Osteomalacia), A. Caniggia, B. Frediani
Bone Absorptiometry In Metabolic Bone Disease: Baseline Values And Long-Term Treatment With Calcitriol (Post-Menopausal Osteoporosis Versus Osteomalacia), A. Caniggia, B. Frediani
Cells and Materials
Total body bone absorptiometry reveals low mineral density in both postmenopausal osteoporosis and osteomalacia patients. The method was used to investigate the effect of calcitriol administration on patients suffering from one of these conditions. In osteomalacia, the administration of calcitriol resulted in a dramatic improvement in bone mineral density (sometimes up to 50% in 12 months), indicating the rapid mineralization of previously uncalcified bone tissue as a result of the normalization of the Ca x P product. In osteoporosis a similar treatment was seen to halt the progressive decrease in bone mineral levels and sometimes resulted in minor increases in …