bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of surface morphology and wettability on the inflammatory response against poly(L‐lactic acid): A semi‐quantitative study with monoclonal antibodies
Authors: Lam K. H. , Schakenraad J. M. , Groen H. , Esselbrugge H. , Dijkstra P. J. , Feijen J. , Nieuwenhuis P. 
Published: December 2004

AbstractIn this study, the influence of surface morphology and wettability of both degradable and nondegradable polymer films on the inflammatory response after subcutaneous implantation in the rat was investigated. Degradable nonporous, porous, and “combi” (porous with a nonporous layer on one side) poly(L‐lactic acid) (PLLA) films and nondegradable polytetrafluoroethylene (PTFE) and (porous) expanded PTFE (e‐PTFE) were used. Contact angles measurements indicate that PLLA is more hydrophillic than PTFE. Assessment of the inflammatory response was performed after various periods of implantation (up till 180 days), with both conventional light microscopy and immunohistochemistry using monoclonal antibodies (mAbs). The inflammatory response observed initially can largely be considered as part of the wound healing reaction, and up till day 40 the inflammatory response against PLLA was minimally more intense than against PTFE (porous as well as nonporous). From day 40 on, the PLLA films provoke a more intense inflammatory response as compared to the PTFE films. Both porous PLLA and the porous side of the “combi” PLLA film provoke a more intense inflammatory response than nonporous PLLA and the nonporous side of the “combi” PLLA film, respectively. In general, PTFE and e‐PTFE films provoke an inflammatory response which is minimally more intense than the one provoked by the sham operation. Almost no ingrowth of tissue was observed in the porous e‐PTFE films. In contrast, there was abundant tissue ingrowth in and an inflammatory response against porous PLLA. It can be concluded that biodegradable PLLA films provoke a more intense inflammatory response than nondegradable PTFE films. Also, porosity enhances the inflammatory response. However, porosity enhances the inflammatory response only when the wettability of a biomaterial permits cellular ingrowth. © 1995 John Wiley & Sons, Inc.
Activity of enzyme immobilized on silanized Co‐Cr‐Mo
Authors: Puleo D. A. 
Published: December 2004

AbstractThe surface of an orthopedic biomaterial was modified by the covalent immobilization of biomolecules. Derivatization of Co‐Cr‐Mo samples with organic and aqueous solutions of γ‐aminopropyltriethoxysilane (APS) resulted in a concentration‐dependent number of reactive NH2 groups on the surface available for coupling to protein. The enzyme trypsin was used as a model biomolecule to investigate the effect of immobilization on proteolytic activity. Trypsin was coupled to the silanized samples by formation of Schiff's base linkages via glutaraldehyde. The nature of the interaction between trypsin and biomaterial was then probed by treatment with concentrated guanidine hydrochloride (Gu‐HCl) and urea. Residual activity (following treatment with chaotropic agents) of trypsin immobilized on silanized Co‐Cr‐Mo was dependent both on the nature of the silane solution and on the type of chaotropic agent. Organic silanization with APS required a miniumum density of approximately 49 NH2 per nm2 of nominal surface area (>0.021 M APS) for residual activity of immobilized trypsin. For aqueous silanization, approximately 5.4 NH2/nm2 (0.51 M APS) resulted in maximal residual trypsin activity. Treatment with GuHCl removed more trypsin activity from Co‐Cr‐Mo samples silanized with organic solutions of APS than did treatment with urea. On the contrary, with aqueous silanization the samples possessed greater residual activity followig treatment with GuHCl than following urea. Compared to simple adsorption with protein onto Co‐Cr‐Mo, both methods of silanization with APS resulted in superior residual immobilized enzyme activity. © 1995 John Wiley & Sons, Inc.
Biological evaluation of the effect of magnetron sputtered Ca/P coatings on osteoblast‐like cells in vitro
Authors: Hulshoff J. E. G. , van Dijk K. , van Der Waerden J. P. C. M. , Wolke J. G. C. , Ginsel L. A. , Jansen J. A. 
Published: December 2004

AbstractA rat bone marrow cell culture was used to evaluate the osteogenic potential of amorphous and crystalline thin calcium phosphate (Ca/P) coatings. The coatings were deposited on titanium discs using a radiofrequency magnetron sputter procedure. Amorphous and crystalline plasma spray Ca/P coated and noncoated titanium discs served as reference material. The cellular behavior was analyzed with quantitative (attachment and proliferation rates) and qualitative (scanning electron microscopy) techniques. No significant differences were found in cell attachment and proliferation rates between the various materials. Scanning electron microscopy showed extracellular matrix formation after 18 days of culture on amorphous plasma‐sprayed and the two types of magnetron sputtered coatings. Furthermore, no severe degradation of the magnetron sputtered coatings was observed. They even appeared to induce apatite formation. On basis of the results, we conclude that magnetron sputtering appears to be a promising method to manufacture bioactive ceramic coatings. © 1995 John Wiley & Sons, Inc.
The use of xenogeneic small intestinal submucosa as a biomaterial for Achille's tendon repair in a dog model
Authors: Badylak Stephen F. , Tullius Robert , Kokini Klod , Shelbourne K. Donald , Klootwyk Thomas , Voytik Sherry L. , Kraine Meredith R. , Simmons Cassandra 
Published: December 2004

AbstractA study was conducted to evaluate the tissue response to a xenogeneic biomaterial when this material was used to repair an experimentally induced Achilles tendon defect in the dog. Twenty dogs had a 1.5 cm segmental defect of the Achilles tendon created surgically which was then reparired with acellular connective tissue derived from porcine small intestinal submucosa (SIS). The animals were sacrificed at 1, 2, 4, 8, 12, 16, 24, and 48 weeks and the neotendons examined for uniaxial longitudinal tensile strength, morphologic appearance, hydroxyproline (collagen) content, and disappearance of the originally implanted SIS material over time. The contralateral normal Achilles tendons served as controls as did four additional dogs that had a 1.5 cm segmental Achilles tendon defect created surgically without subsequent surgical repair with SIS. Results showed the SIS remodeled neotendons to be stronger than the musculotendinous origin or the boney insertion (>1000 N) by 12 weeks after surgery and to consist of organized collagen‐rich connective tissue similar to the contralateral normal tendons. The four dogs in which no SIS was implanted showed inferior strength at the comparable time points of 4, 8, 12, and 16 weeks. Immunohistochemical studies suggest that the SIS biomaterial becomes degraded within the first eight weeks and serves as a temporary scaffold around which the body deposits appropriate and organized connective tissue. SIS is a promising biomaterial worthy of further investigation for orthopedic soft tissue applications. © 1995 John Wiley & Sons, Inc.
A transmission electron microscopy examination of the interface between osteoblasts and metal biomaterials
Authors: Garvey B. T. , Bizios R. 
Published: December 2004

AbstractTransmission electron microscopy was used to examine the interface between metal implant materials and bone cells. Specifically, neonatal rat calvaria osteoblasts were cultured on CoCrMo alloy and on 316L stainless steel discs (mechanically polished to a 0.3 μm finish) in Dulbecco's Modified Eagle Medium (supplemented with 10% fetal bovine serum, 50 μg/mL ascorbic acid, and 10 mM ß‐glycerophosphate) under standard, sterile, cell culture conditions for 14 to 28 days. At the end of the prescribed time periods, the cells were fixed and embedded in resin before removing the metal substrates using an electrolytic dissolution technique and a 7% NaCl solution. Transmission electron microscopic examination of stained, ultrathin sections of the biological samples revealed an intact interface with microscopic details characteristic to the cell line and similar to those reported in the literature for animal and explant studies. The osteoblasts exhibited continous contact and intimate apposition to both the CoCrMo and stainless steel substrate surfaces and grew in multilayered structures; an electron dense layer (composed of mucopolysaccharides and proteins) was observed at the surface of both substrates; collagen fibrils and mineralized foci were observed in the extracellular matrix interspersed among the multilayered osteoblasts. © 1995 John Wiley & Sons, Inc.
Modulation of adhesive properties of DEAE‐dextran with laminin
Authors: Varani James , Fligiel Suzanne E. G. , Inman Dennis R. , Beals Ted F. , Hillegas William J. 
Published: December 2004

AbstractHuman squamous epithelial cells produce lower amounts of laminin and fibronectin when cultured on DEAE‐dextran than when cultured on gelatin‐coated polystyrene (Biotechnol. Bioeng., 33:1235). The epithelial cells also spread much more slowly on DEAE‐dextran than they do on gelatincoated polystyrene. To determine if the low level of matrix production by cells grown on DEAE‐dextran contributed to the slowness of cell spreading on this substrate, microcarriers made from DEAE‐dextran were treated with exogenous laminin (10 μg/cm2 of surface area) and then examined for ability to support cell adhesion. Squamous epithelial cells spread as rapidly on the laminin‐treated DEAE‐dextran as they did on gelatin‐coated polystyrene (much more rapidly than on untreated DEAE‐dextran). This indicates (1) that laminin can bind to DEAE‐dextran in a fashion that is biologically usable by anchorage‐dependent cells, and (2) that when laminin is bound to DEAE‐dextran, the failure of squamous epithelial cells to rapidly spread is overcome. These data support the hypothesis that failure of the cells to synthesize an intact extracellular matrix on DEAE‐dextran is responsible, at least in part, for the slowness with which cells spread on this substrate. © 1995 John Wiley & Sons, Inc.
Ultrastructural changes in cultured human periodontal ligament cells exposed to dental materials
Authors: Adams A. M. , Soames J. V. , Searle R. F. 
Published: December 2004

AbstractThe cytopathic effects of a range of dental restorative cements were examined by electron microscopy using an in vitro model with cultured test cells derived from human periodontal ligament. Monolayers were fixed and processed in situ after 2, 24, and 48 h exposure. Many cells showed lysis after two hours exposure consistent with immediate acute injury. Cultures subsequently recovered, reflecting different susceptibilities of cells to injury, and at later stages showed distinct patterns of cell damage in response to different restorative materials. These were related primarily to either cytoplasmic or nuclear damage and to changes resembling apoptosis. © 1995 John Wiley & Sons, Inc.
Contact activation of the plasma coagulation cascade. I. Procoagulant surface chemistry and energy
Authors: Vogler Erwin A. , Graper Jane C. , Harper Garry R. , Sugg Harry W. , Lander Lorraine M. , Brittain William J. 
Published: December 2004

AbstractContact activation of the intrinsic pathway of porcine blood plasma coagulation is shown to be a steep exponential‐like function of procoagulant surface energy, with low activation observed for poorly water‐wettable surfaces and very high activation for fully water‐wettable surfaces. Test procoagulants studied were a system of oxidized polystyrene films with varying wettability (surface energy) and glass discs bearing close‐packed self‐assembled silane monolayers (SAMs) with well‐defined chemistry consisting of 12 different terminating chemical functionalities. A monotonic trend of increasing coagulation activation with increasing water wettability was observed for the oxidized polystyrene system whereas results with SAM procoagulants suggested a level of chemical specificity over and above the surface energy trend. In particular, it was noted that coagulation activation by SAMs terminated with CO2H was much higher than anticipated based on surface wettability whereas NH3⊕‐terminated SAMs exhibited very low procoagulant activity. SAMs terminated in (CH2)2(CF2)7CF3 behaved as anticipated based on surface energy with very low procoagulant activity and did not exhibit special properties sometimes attributed to perfluorinated compounds. Quantitative ranking of the inherent coagulation activation properties of procoagulant surfaces was obtained by application of a straightforward phenomenological model expressed in a closed‐form mathematical equation relating coagulation time to procoagulant surface area. Fit of the model with a single adjustable parameter to experimental measurements of porcine platelet‐poor plasma coagulation time was very good, implying that assertions and simplifications of the model adequately simulated reality. Two important propositions of the model were that (1) the number of putative “activating sites” scaled linearly with procoagulant surface area, and (2) contact activation of the plasma coagulation cascade was catalytic in the sense that these activating sites were not consumed or “poisoned” by irreversible or slowly reversible protein adsorption during coagulation. An extension of the coagulation model proposed that procoagulant activation properties scale exponentially with the surface density of polar (acid‐base) sites, which, in turn, was related to procoagulant wettability. © 1995 John Wiley & Sons, Inc.
Photochemical surface derivatization of a peptide containing Arg–Gly–Asp (RGD)
Authors: Sugawara Takashi , Matsuda Takehisa 
Published: December 2004

AbstractA photoreactive octapeptide (Gly–Gly–Gly–Arg–Gly–Asp–Ser–Pro), into which the cell adhesive tripeptidyl sequence Arg–Gly–Asp (RGD) was incorporated, was derivatized with 4‐azidobenzoyloxysuccinimide at its N‐terminal. Photochemical surface immobilization of the RGD peptide on poly (vinyl alcohol) (PVA) was performed by adsorption and subsequent ultraviolet (UV) irradiation and was evidenced by electron spectra for chemical analysis (ESCA) measurements. Bovine endothelial cells (ECs) adhered and spread well on the RGD peptide‐derivatized surfaces in a biologically specific manner. The use of a photomask during UV irradiation enabled preparation of a two‐dimensional tissue with micron‐order precision. Thus surface immobilization of a photoreactive, cell‐adhesive peptide easily can create a cell attachment surface at a desired portion or region of a polymer surface or device. © 1995 John Wiley & Sons, Inc.
Comparison of the release of growth hormone from hydroxyapatite, heat‐treated hydroxyapatite, and fluoroapatite coatings on titanium
Authors: Downes S. , Clifford C. J. , Scotchford C. , Klein C. P. A. T. 
Published: December 2004

AbstractHydroxyapatite (HA), heat‐treated hydroxyapatite (HAH), and fluorapatite (FA) coatings on titanium were loaded with human growth hormone (GH), and the subsequent release was monitored in vitro. The amount of GH released was significantly increased from the HA coating that had received a post‐plasma‐spraying heat treatment prior to incorporation of the growth hormone. Scanning electron microscopy was used to assess the surfaces of the ceramic coatings prior and postincubation with GH. Surface changes were observed on the HA and HAH coatings but not on the FA coatings after incubation with GH. Osteoblast‐like cells were grown on the coatings and maintained in culture. Scanning electron microscopy was used to study the morphology of the cells and the interaction of the cells with the ceramic coatings. We used thymidine uptake and DNA content to determine the relative rates of cell division on the different coatings; the optimum rate of cell proliferation was observed on the HAH coating loaded with 0.1 IU/mL GH. © 1995 John Wiley & Sons, Inc.
Bone‐bonding behavior under load‐bearing conditions of an alumina ceramic implant incorporating beads coated with glass–ceramic containing apatite and wollastonite
Authors: Li Zhong‐Lian , Kitsugi Toshiaki , Yamamuro Takao , Chang Yong‐Sun , Senaha Yoshinaga , Takagi Haruki , Nakamura Takashi , Oka Masanori 
Published: December 2004

AbstractAlumina ceramic with a porous surface coated with glass‐ceramic containing apatite and wollastonite (AW‐GC) was implanted in a state of press‐fit under loas‐bearing conditions in the femoral condylus of the mongrel dog and compared with a non‐glass‐ceramic‐coated alumina ceramic. A trapezoid alumina ceramic implant (7 × 10 × 5 mm) with a lateral recess (0.9 mm deep) coated with alumina ceramic beads (mean diameter, 750 μm) in a single layer was prepared. The alumina ceramic beads were bonded to the alumina ceramic substratum using an identical alumina binder. The thickness of coating was 10–50 μm (mean, 30 μm). The surface of the beads and the substratum of the alumina implant were coated with AW‐GC. A pull‐out test and histologic examination were performed at 4, 8, and 24 weeks after implantation. The interfacial shear load was significantly increased from 8 to 24 weeks in both groups. The shear load of the glass‐ceramic‐coated implant was significantly greater than that of the noncoated implant at every stage. The interface shear load of the noncoated implant was 12.13 ± 2.76 kg at 4 weeks, 13.92 ± 4.18 kg at 8 weeks, and 24.17 ± 5.17 kg at 24 weeks after implantation. The interface shear load of the glass‐ceramic‐coated implant was 17.96 ± 2.81 kg at 4 weeks, 24.92 ± 9.87 kg at 8 weeks, and 34.83 ± 4.12 kg at 24 weeks after implantation. Histologic examination showed more ingrown bone tissue in the glass‐ceramic‐coated implants. It is suggested that AW‐GC stimulated the bone ingrowth. The bonding behavior of bioinert alumina ceramics is therefore improved by a coating of bioactive glass‐ceramic. © 1995 John Wiley & Sons, Inc.
Cellular responses to chemical and morphologic aspects of biomaterial surfaces. I. A novel in vitro model system
Authors: Chesmel K. D. , Black J. 
Published: December 2004

AbstractThe clinical success of any implant is directly dependent upon the cellular behavior in the immediate vicinity of the interface established between the host tissue and the biomaterial(s) used to fabricate the device. All biomaterials have morphologic, chemical, and electrical surface characteristics that influence the cellular response to the implant. Quantitative measurement of specific aspects of this local host response to different but well‐characterized biomaterial surfaces provides a crucial link in the understanding of the overall phenomenon of implant biocompatibility. A system has been devised for in vitro examination of responses of cells to controlled but independent changes in both the chemistry and morphology of polystyrene (PS) tissue culture surfaces. Micromachined silicon wafers were used as templates to solvent‐cast PS replicas [using 0, 1, or 2 wt % styrene (S) monomer additions] with either none, 0.5‐ or 5.0‐μm‐deep surface grooves arranged in a radial array. When all possible morphologies were combined with all possible polymers, nine model biomaterial surfaces (MBSs) were produced. The chemical characteristics of the MBSs were determined using electron spectroscopy for chemical analysis, secondary ion mass spectroscopy, and contact angle techniques and were found to be distinct. The types and amount of proteins that adsorb onto these surfaces from serum containing media were examined and found to consist of multiple molecular layers of relatively uniform composition. Self‐contained tissue culture vessels formed from the MBSs were capable of supporting the growth of confluent cultures of rat calvarial cells. The model biomaterial system described here can be used to examine how simultaneous stimuli resulting from the chemical and morphological characteristics of a test material may influence biologic responses. Such multifactorial biocompatibility research is needed to properly document material‐host interactions. © 1995 John Wiley & Sons, Inc.
Local delivery of indomethacin by a polyorthoester inhibits resossification of experimental bone defects
Authors: Solheim Eirik , Pinholt Else Mari , Andersen Rune , Bang Gisle , Sudmann Einar 
Published: December 2004

AbstractInhibition of orthotopic reossification after surgical removal of bone is sometimes indicated and may be accomplished by implantation of interpositional materials or by systemic administration of indomethacin. However, implantation of nonresorbable foreign material may induce a chronic inflammation and predispose to infections; and systemic administration of indomethancin may induce systemic adverse effects. We studied the effect of local delivery of indomethacin by a bioerodible polyorthoester on the reossification of segmental defects of the radius in rats. We divided 45 Wistar rats into three groups, A–C. A 3.5 mm‐long middiaphyseal osteoperiosteal resection of the right radius was made in each rat. The defect was filled with 15 mg of polyorthoester with 5% indomethacin in group A and 15 mg of polyorthoester without drug in group B. No material was implanted in the defects in the group C rats. The rats were killed 50 days postoperatively. The mean area of the residual defects were greater in the defects with the polyorthoester with 5% indomethacin compared with defects with polyorthoester without drug or without implant as judged by computer‐assisted area measurements on radiographs. By light microscopy, no inflammation was seen and only traces of the polyorthoester could be dected in the defects filled with the polyorthoester with or without indomethacin. The results of this study suggest that the polyorthoester may be used as a bioerodible system for local delivery of indomethacin to inhibit reossification of skeletal defects without tissue reaction, unabsorbed carrier, or systemic effects. © 1995 John Wiley & Sons, Inc.
Polysulphone inhibits final differentiation steps of osteogenesis in vitro
Authors: van Loon Jack J. W. A. , Bierkens Johan , Maes Jef , Schoeters Greet E. R. , Ooms Daniella , Doulabi Behrouz Zandieh , Veldhuijzen J. Paul 
Published: December 2004

AbstractBiocompatibility is an important factor in the development of orthopedic implants as well as in the development of new tissue culture devices. Polysulphone has been used for orthopedic implants because of its mechanical properties, ease of sterilization, molding capacity, and biocompatibility. Therefore, polysulphone has been chosen as the prime material for the construction of tissue culture devices to be used for the cultivation of osteogenic cells (preosteoblastlike MN7 cells and primary bone marrow fragments), as well as complete fetal long bone explants under space flight conditions. Whereas polysulphone did not interfere with the proliferation in early stages of bone‐forming cells, we show that leachable factors within the polysulphone polymer prevented the final steps of matrix formation as measured by collagen synthesis and matrix mineralization. These data argue against polysulphone as a material for orthopedic implants. © 1995 John Wiley & Sons, Inc.