bluuebunny/crossref_metadata_2025_split huggingface dataset:
Apatite coated on organic polymers by biomimetic process: Improvement in its adhesion to substrate by glow‐discharge treatment
Authors: Tanahashi M. , Yao T. , Kokubo T. , Minoda M. , Miyamoto T. , Nakamura T. , Yamamura T. 
Published: December 2004

AbstractA dense, uniform, and highly biologically active bone‐like apatite layer can be formed in arbitrary thickness on any kind and shape of solid substrate surface by the following biomimetic method at ordinary temperature and pressure: First, a substrate is set in contact with particles of bioactive CaOSiO2‐based glass soaked in a simulated body fluid (SBF) with inorganic ion concentrations nearly equal to those of human blood plasma so that a number of apatite nuclei are formed on the substrate. Second, the substrate is soaked in another solution with ion concentrations 1.5 times those of SBF (1.5SBF) so that the apatite nuclei grow in situ. In the present study, organic polymer substrates were treated with glow‐discharge in O2 gas atmosphere, then subjected to the above‐mentioned biomimetic process. The induction periods for the apatite nucleation on all the examined organic polymers were reduced from 24 to 6 h, with glow‐discharge treatment. The adhesive strengths of the formed apatite layer to the substrates increased from about 4 to 10 MPa for poly(ethylene terephthalate) and poly‐ether sulfone, and from 1 ∼ 2 to 6 ∼ 7 MPa even for poly(methyl methacrylate), polyamide 6 and polyethylene. It is supposed that highly polar groups such as carbonyl, ester, hydroxyl, and carboxyl ones formed by glow‐discharge treatment increased the affinity of a silicate ion with the substrates to decrease the induction period, and also increased the affinity of the apatite with the substrate to increase the adhesive strength. The apatite‐organic polymer composites thus obtained are expected to be useful as bone‐repairing materials as well as soft tissue‐repairing materials. © 1995 John Wiley & Sons, Inc.
Adsorption–Desorption of proteins on phospholipid polymer surfaces evaluated by dynamic contact angle measurement
Authors: Ueda Tomoko , Ishihara Kazuhiko , Nakabayashi Nobuo 
Published: December 2004

AbstractAdsorption‐desorption of plasma protein on various polymer membranes was evaluated by a dynamic contact angle (DCA) measurement using the Wilhelmy plate method. Poly(ethylene terephthalate) (PET) was used as a substrate membrane; we examined this membrane coated with hydrophilic polymers such as poly[2‐methacryloyloxyethyl phosphorylcholine (MPC)‐co‐n‐butyl methacrylate (BMA)] or poly[2‐hydroxyethyl methacrylate (HEMA)]. Although the λ‐potential of the PET membrane was negative, the coating with poly(MPC‐co‐BMA) induced increase of value to nearly zero. The DCA loops observed on the polymer membranes after protein adsorption were unity and hysteresis of the loop was reduced. In the cases of protein adsorbed on both the PET and the poly(HEMA) membranes, the shape and hysteresis of the loops were almost same during the rinsing process with a phosphate‐buffered solution (PBS). However, the hysteresis of the DCA loops that appeared on the protein‐adsorbed poly(MPC‐co‐BMA) membrane became large during the rinsing process with the PBS, and the shape of the DCA loop returned to its non‐protein‐adsorbed state. Therefore, proteins adsorbed on poly(MPC‐co‐BMA) could desorb more readily than those on PET and poly(HEMA) because of the weak interaction between poly(MPC‐co‐BMA) and the proteins. © 1995 John Wiley & Sons, Inc.
Effect of titanium surface roughness on proliferation, differentiation, and protein synthesis of human osteoblast‐like cells (MG63)
Authors: Martin J. Y. , Schwartz Z. , Hummert T. W. , Schraub D. M. , Simpson J. , Lankford J. , Dean D. D. , Cochran D. L. , Boyan B. D. 
Published: December 2004

AbstractThe effect of surface roughness on osteoblast proliferation, differentiation, and protein synthesis was examined. Human osteoblast‐like cells (MG63) were cultured on titanium (Ti) disks that had been prepared by one of five different treatment regimens. All disks were pretreated with hydrofluoric acid‐nitric acid and washed (PT). PT disks were also: washed, and then electropolished (EP); fine sandblasted, etched with HCl and H2SO4, and washed (FA); coarse sandblasted, etched with HCl and H2SO4, and washed (CA); or Ti plasma‐sprayed (TPS). Standard tissue culture plastic was used as a control. Surface topography and profile were evaluated by brightfield and darkfield microscopy, cold field emission scanning electron microscopy, and laser confocal microscopy, while chemical composition was mapped using energy dispersion X‐ray analysis and elemental distribution determined using Auger electron spectroscopy. The effect of surface roughness on the cells was evaluated by measuring cell number, [3H]thymidine incorporation into DNA, alkaline phosphatase specific activity, [3H]uridine incorporation into RNA, [3H]proline incorporation into collagenase digestible protein (CDP) and noncollagenase‐digestible protein (NCP), and [35S]sulfate incorporation into proteoglycan.Based on surface analysis, the five different Ti surfaces were ranked in order of smoothest to roughest: EP, PT, FA, CA, and TPS. A TiO2layer was found on all surfaces that ranged in thickness from 100 Å in the smoothest group to 300 Å in the roughest. When compared to confluent cultures of cells on plastic, the number of cells was reduced on the TPS surfaces and increased on the EP surfaces, while the number of cells on the other surfaces was equivalent to plastic. [3H]Thymidine incorporation was inversely related to surface roughness. Alkaline phosphatase specific activity in isolated cells was found to decrease with increasing surface roughness, except for those cells cultured on CA. In contrast, enzyme activity in the cell layer was only decreased in cultures grown on FA‐ and TPS‐treated surfaces. A direct correlation between surface roughness and RNA and CDP production was found. Surface roughness had no apparent effect on NCP production. Proteoglycan synthesis by the cells was inhibited on all the surfaces studied, with the largest inhibition observed in the CA and EP groups. These results demonstrate that surface roughness alters osteoblast proliferation, differentiation, and matrix productionin vitro. The results also suggest that implant surface roughness may play a role in determining phenotypic expression of cellsin vivo.
Surface characteristics and properties of lumbrokinase‐immobilized polyurethane
Authors: Ryu Gyu Ha , Han Dong Keun , Park Seonyang , Kim Miran , Kim Young Ha , Min Byounggoo 
Published: December 2004

AbstractPotent and novel fibrinolytic enzymes (lumbrokinase [LK]) were extracted from the earthworm, Lumbricus rubellus. These enzymes were very stable and showed greater antithrombotic activity than other currently used fibrinolytic proteins. An LK fraction showing the most potent fibrinolytic activity was immobilized onto a polyurethane (PU) surface to investigate its enzymatic activity and antithrombotic activity. A methanol‐extracted PU surface was coated with 3% (wt/vol) maleic anhydride methylvinyl ether copolymer (MAMEC)/tetrahydrofuran (THF) solution, and the surface was incubated in an LK solution/phosphate‐buffered saline (PBS, pH 7.4). The surface properties were characterized by attenuated total reflectance‐Fourier transform infrared spectroscopy (ATR‐FTIR), electron spectroscopy for chemical analysis (ESCA), and dynamic contact angle. The stability of immobilized LK was determined by caseinolytic activity assay and the specificity of immobilized LK on fibrinogen/fibrin was observed by sodium dodecyl sulphate‐polyacrylamide gel electrophoresis (SDS‐PAGE). The antithrombotic activity of immobilized LK was evaluated using an ex vivo rabbit A‐A shunt experiment. LK immobilization was confirmed by ATR‐FTIR and ESCA. Immobilized LK demonstrated stable proteolytic activity during various incubation periods. Immobilized LK proteolyzed fibrinogen and fibrin almost specifically, while it hardly hydrolyzed other plasma proteins including plasminogen and albumin. In the ex vivo A‐A shunt experiment, the LK‐immobilized surface significantly prolonged occlusion time over control surfaces. This is primarily due to the high thrombolytic activity of immobilized LK. In this work, a highly efficient surface modification method on the PU surface was developed, and this LK immobilization technique will be very useful in improving the blood compatibility of blood‐contacting devices. © 1995 John Wiley & Sons, Inc.
In vitro fatigue testing of a dental bonding system on enamel
Authors: Ruse N. D. , Shew R. , Feduik D. 
Published: December 2004

AbstractThe aim of this study was to investigate the in vitro fatigue behavior of a dental bonding system [ScotchBond Multi Purpose (SBMP)] by using a cyclic shear loading test. Cylinders of a light‐cured hybrid composite resin (Z100) were formed on, and bonded with SBMP to, the flattened, acid‐etched enamel surface of human teeth. Thirty‐two samples (eight per group) were used to determine the 1‐h, 1‐day, 7‐day, and 30‐day shear bond strengths. For the shear fatigue test, the stress was cycled, at a rate of 1Hz, between 0 and a preset value in the 12–28 MPa range (from ‐3 SD to + 1 SD around the 24‐MPa mean bond strength of the 1‐h specimens). The applied stress and the number of cycles to failure were recorded for each of the 75 samples tested (15 samples per set‐stress). Three stress versus number of cycles curves (low, median, and high S‐N curves) were obtained and an approximate endurance limit of 10 MPa was identified for the SBMP bonding system. The data obtained explain, in part, the discrepancy between in vitro and in vivo results and underline the difficulty of predicting the in vivo behavior based on results of in vitro bond strength tests alone. Shear fatigue test data, however, could provide a better insight into the long‐term in vivo behavior of a dental bonding system. © 1995 John Wiley & Sons, Inc.
Wettability and interfacial interactions in bioceramic‐body‐liquid systems
Authors: Agathopoulos S. , Nikolopoulos P. 
Published: December 2004

AbstractWetting experiments, by the sessile drop technique, were carried out at 37°C in air to determine the surface and interfacial interactions that take place in various solid bioceramics based on Al2O3, ZrO2(YPZ), SiO2, and TiO2 in contact with water, Ringer solution, artificial synovial fluid, calf serum, human plasma, and whole blood (+ EDTA). The surface energy of the liquids was measured by the ring method. The calculated values of the energy of interaction (work of adhesion) reveal that intermolecular forces act across the solid‐liquid interfaces. The contribution of the dispersion and polar interactions to the surface energy of the polar liquids and the pure or mixed oxides was determined assuming that in the system of Mn‐steel‐liquids only dispersion forces act at the interface. It was found that the contribution of the polar interactions to the energy of interaction at the solid‐liquid interface increases with the glassy phase content of the oxide that causes reduction of the measured contact angle. © 1995 John Wiley & Sons, Inc.
Effect of parallel surface microgrooves and surface energy on cell growth
Authors: Den Braber E. T. , de Ruijter J. E. , Smits H. T. J. , Ginsel L. A. , von Recum A. F. , Jansen J. A. 
Published: December 2004

AbstractTo evaluate the effect of surface treatment and surface microtexture on cellular behavior, smooth and microtextured silicone substrata were produced. The microtextured substrata possessed parallel surface grooves with a width and spacing of 2.0 (SilD02), 5.0 (SilD05), and 10 μm (SilD10). The groove depth was approximately 0.5 μm. Subsequently, these substrata were either left untreated (NT) or treated by ultraviolet irradiation (UV), radiofrequency glow discharge treatment (RFGD), or both (UVRFGD). After characterization of the substrata, rat dermal fibroblasts (RDF) were cultured on the UV, RFGD, and UVRFGD treated surfaces for 1, 3, 5, and 7 days. Comparison between the NT and UV substrata revealed that UV treatment did not influence the contact angles and surface energies of surfaces with a similar surface topography. However, the contact angles of the RFGD and UVRFGD substrata were significantly smaller than those of the UV and NT substrata. The dimension of the surface microevents did not influence the wettability characteristics. Cell culture experiments revealed that RDF cell growth on UV‐treated surfaces was lower than on the RFGD and UVRFGD substrata. SEM examination demonstrated that the parallel surface grooves on the SilD02 and SilD05 substrata were able to induce stronger cell orientation and alignment than the events on SilD10 surfaces. By combining all of our findings, the most important conclusion was that physicochemical parameters such as wettability and surface free energy influence cell growth but play no measurable role in the shape and orientation of cells on microtextured surfaces. © 1995 John Wiley & Sons, Inc.
Metabolic response of granulocytes and platelets to synthetic vascular grafts: Preliminary results with an in vitro technique
Authors: Pärsson Håkan , Nässberger Lennart , Thörne Johan , Norgren Lars 
Published: December 2004

AbstractThe metabolism of granulocytes as well as platelets evoked by incubation with different synthetic vascular grafts was monitored during 6‐h batch experiments using microcalorimetry. Standard knitted Dacron grafts, ePTFE‐grafts, knitted Dacron grafts with collagen impregnation, and knitted Dacron grafts with external collagen‐coating were used. The heat production per cell was calculated. A rapid increase of metabolic activity followed by a gradual decrease was demonstrated with both granulocyte suspension and platelet concentrate. Significant differences were obtained between the materials with a maximum response of Dacron grafts with collagen impregnation for both granulocyte and platelet response. The materials had different surface morphologies regarding cell adhesion after incubation as demonstrated with scanning electron microscopy with more pronounced adhesion on the collagen‐impregnated grafts. The results suggest that macrocalorimetry may be useful for the evaluation of cellular reactions on different biomaterials. However, further studies have to reveal the specificity of the reactions. © 1995 John Wiley & Sons, Inc.
Surface and blood‐contacting properties of alkylsiloxane monolayers supported on silicone rubber
Authors: Silver James H. , Hergenrother Robert W. , Lin Jui‐Che , Lim Florencia , Lin Horng‐Ban , Okada Toshiyuki , Chaudhury Manoj K. , Cooper Stuart L. 
Published: December 2004

AbstractSelf‐assembled monolayers of alkylsiloxanes supported on polydimethyl siloxane (PDMS) rubber were used as model systems to study the relation between blood compatibility and surface chemistry. The inner lumen of PDMS tubes was first treated with an oxygen plasma. The resultant oxidized surfaces were postderivatized by reacting them with alkyltrichlorosilanes to form the monolayer films. The chemical properties of the monolayers were controlled by varying the head‐group chemical compositions. Surface derivatization was verified using variable‐angle X‐ray photoelectron spectroscopy (XPS or ESCA). Blood compatibility was evaluated using a canine ex vivo arteriovenous series shunt model. Surfaces grafted with hydrophobic head‐groups as ‐CH3 and ‐CF3 had significantly lower platelet and fibrinogen deposition than the surfaces composed of hydrophilic groups such as ‐CO2CH3, ‐(CH2CH2O)3COCH3, and ‐(OCH2CH2)3OH. © 1995 John Wiley & Sons, Inc.
Bioactive bone cement: The effect of amounts of glass powder and histologic changes with time
Authors: Tamura Jiro , Kawanabe Keiichi , Yamamuro Takao , Nakamura Takashi , Kokubo Tadashi , Yoshihara Satoru , Shibuya Takehiro 
Published: December 2004

AbstractA study was conducted to examine the influence of the amount of glass powder added to a bioactive bone cement of our formula on its mechanical and biologic properties. Serial changes in the cement with time were also examined. The bioactive bone cement consisted of CaO‐SiO2P2O5CaF2 glass powder and bisphenol‐a‐glycidyl methacrylate resin. Glass powder was added to the cement in 30, 50, 70, and 80% weight ratios. The compressive strengths of the resulting cements (171–239 MPa) were more than double that of polymethylmethacrylate cement (68 MPa). Histologic examination of rat tibiae bearing artificial defects packed with each bioactive cement showed direct bone contact 4 weeks after surgery. The cement with a higher percentage of glass powder showed better direct formation of bone around its periphery with a thicker reactive layer. Under scanning electron microscopic observation, the reactive layer showed increased levels of calcium and phosphorus. Examination of histologic changes up to 26 weeks showed progressive bone formation around the cement and no sign of biodegradation. © 1995 John Wiley & Sons, Inc.
Dynamic creep behavior of acrylic bone cement
Authors: Verdonschot Nico , Huiskes Rik 
Published: December 2004

AbstractRecent studies concerning the fixation of cemented total hip arthroplasty (THA) have led to new hypotheses about the dynamic, long‐term failure mechanisms leading to prosthetic loosening. As a result, the long‐term mechanical behavior of acrylic bone cement has gained more interest since little is known about these properties. In this study, the dynamic, compressive creep deformation of acrylic bone cement was examined. An amount of creep was found, with creep strains exceeding the elastic strain during 14 × 106 loading cycles. There was a linear relationship between the logarithmic values of the number of loading cycles and the creep strain. The effect of stress level on the amount of creep was different from that in results of static experiments reported in the literature. Comparing the results with tensile creep experiments revealed that bone cement under a tensile load creeps much quicker than under a compressive one. Young's modulus was significantly higher when the material was loaded at higher strain rates. The bone cement became stiffer with an increasing number of loading cycles. The creep behavior of bone cement is important for the long‐term behavior of cemented THA. It enables subsidence of the stem and attenuation of stress peaks in the cement mantle. © 1995 John Wiley & Sons, Inc.
Determination of the mineral phases and structure of the bone‐implant interface using raman spectroscopy
Authors: Leung Yiuchong , Anton Walters M. , Blumenthal Norman C. , Ricci John L. , Spivak Jeff M. 
Published: December 2004

AbstractThe bone‐implant interface formed in a canine distal femur was examined by means of a Raman microprobe using an implant model designed to test calcium phosphate surface coatings. By using the 960 cm−1 band of calcium phosphate to characterize the interface and adjacent mineral, we obtained spatial and compositional information about the attachment of bone to the synthetic calcium phosphate coating on a titanium support. The interface between bone and the synthetic calcium phosphate is approximately 30–40 μm in width. © 1995 John Wiley & Sons, Inc.
Evaluating the dialine® vascular prosthesis knitted from an alternative source of polyester yarns
Authors: King Martin W. , Marois Yves , Guidoin Robert , Ukpabi Pauline , Deng Xiaoyan , Martin Louisette , Pǎris Edouard , Douville Yvan 
Published: December 2004

AbstractThe sudden and unilateral decision by E. I. DuPont de Nemours & Co., Inc., to withdraw its polymers for use in implantable devices has presented the medical device industry with an immediate and serious challenge to find alternative sources of biomaterials. In France, the company Cardial S. A. has already taken steps to find an alternative polyester yarn to replace Dacron® by developing a new arterial prosthesis knitted from polyester yarns supplied by Rhǒne‐Poulene Fibres. This article describes an in vitro and in vivo study of this French device, called the Dialine® prosthesis, with a view to determining its relative performance compared to current American and British prostheses, which rely on DuPont's Dacron® yarn. In addition to analyses of the morphology and textile structure, and measurements of its physical and chemical properties, the Dialine® graft was implanted as a thoracoabdominal bypass in dogs for periods ranging from 4 h to 6 months. In addition to our pathologic and histologic observations, we cleaned and evaluated the explanted prostheses for in vivo changes in dimensions, strength, and crystalline microstructure. The Dialine® graft was found to differ structurally from other polyester prostheses because it is warp‐knitted from a mixture of flat and texturized yarns with finer filaments. Its denser structure has a lower water permeability, greater flexibility and ease of handling, satisfactory strength, and dimensional stability, and it presents different textures on its luminal and external surfaces. The in vivo trial demonstrated that it has excellent biocompatibility and biostability over 6 months. With no thrombi observed on the luminal surface after 3 months, it has a faster rate of healing, generates compact external and internal capsules with a thinner neointima, and has an overall milder inflammatory response than is normally observed with Dacron®‐based prostheses. © 1995 John Wiley & Sons, Inc.
Effect of nickel‐based dental casting alloys on fibroblast metabolism and ultrastructural organization
Authors: Bumgardner J. D. , Doeller J. , Lucas L. C. 
Published: December 2004

AbstractPrevious cell culture evaluations have shown that nickel–chromium dental alloys did not affect cellular viability or morphology. However, nickel‐based alloys released corrosion products which decreased cellular proliferation. It was hypothesized that this decrease was due to an interference of cellular energy metabolism by released metal ions. To test this hypothesis, we evaluated the effects on cellular energy metabolism, adenosine triphosphate (ATP) levels, and cellular ultrastructure by four nickel‐based alloys, including high and low chromium alloys with and without beryllium additions, in human gingival fibroblast cell culture. Energy metabolism was evaluated by measuring glucose‐6‐phosphate dehydrogenase (G‐6‐PDH) activity. ATP levels were measured with the luciferin–luciferase method. Cellular membranes and ultrastructural organization were evaluated by scanning and transmission electron microscopy. The results of this study showed that metal ions released from all alloys completely inhibited G‐6‐PDH activity and reduced cellular ATP levels as compared to controls. The reduction in intracellular ATP was greater for the beryllium containing alloys than the non‐beryllium‐containing alloys. However, no morphologic changes in cellular membranes or organelles were observed. These results support the hypothesis that metal ions released from nickel‐based dental casting alloys interfere with cellular energy metabolism. © 1995 John Wiley & Sons, Inc.