bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modified ethoxyethyl cyanoacrylate for therapeutic embolization of arteriovenous malformation
Authors: Tseng Yin‐Chao , Hyon Suong‐Hyu , Ikada Yoshito , Taki Waro , Uno Akira , Yonekawa Yasuhiro 
Published: December 2004

AbstractAiming at alleviating the problems of using 2‐cyanoacrylates as a material for therapeutic embolization, this experiment made some physical modifications by mixing contrast media. It was found that the physicochemical properties of 2‐cyanoacrylates can be altered by changing the concentration and the composition of the contrast media added. A 50 wt% cyanoacrylate–50 wt% contrast medium mixture has enough radiopacity for the practical requirement for embolization. A mixture of 50 wt% (ethoxyethyl cyanoacrylate‐5 wt% lactide/ ϵ‐caprolactone copolymer), 25 wt% lipiodol and 25 wt% tetrafluorodibro‐moethane provides a viscosity of 13.8 cP, a bonding strength of 14.9 kg/cm2, a set time of 6 s, and a spreading in canine blood of 33 mm. It was concluded that the mixture is much more satisfactory than the conventional cyanoacrylates as an embolus material in vitro. The results obtained by in vivo experiments and clinical trials so far suggest that the mixture is very promising as a material for embolization.
Series shunt evaluation of polyurethane vascular graft materials in chronically AV‐shunted canines
Authors: McCoy Timothy J. , Wabers Hugh D. , Cooper Stuart L. 
Published: December 2004

AbstractWell characterized, laboratory‐synthesized polymeric materials which have been extensively tested for biocompatibility via initial platelet and protein deposition in an acute ex vivo canine model were placed as interpositional series shunts in canines with chronically implanted iliac arteriovenous shunts ex vivo. Platelet deposition was measured on a base polyurethane block copolymer, a sulfonated ionic derivative, an alkyl grafted (C18) derivative, Biomer, polyethylene, and polydimethylsiloxane for 24 h using radiolabeled platelets. Platelet survival and in vitro aggregation were determined to investigate the effects of the shunting pprocedure on experimental animals. The viability of adopting a chronic arteriovenous (iliac) shunted canine model for use with series shunts to evaluate polyurethanes having applications as materials in vascular graft construction was investigated and the results compared with acute model data.
Adsorption of plasma proteins and adhesion of platelets onto novel polyetherurethaneureas—relationship between denaturation of adsorbed proteins and platelet adhesion
Authors: Ito Y. , Sisido M. , Imanishi Y. 
Published: December 2004

AbstractNovel polyetherurethaneureas which have been synthesized by the present authors were chosen for the substrate polymers, on which adhesion of platelets was investigated. The number of adhered platelets and the amount of serotonin released from platelets adhered on the polymers and the protein‐coated polymers were determined by radioisotope method. Both of them were ehanced with increasing content of urea linkages in the polyetherurethaneureas. The platelet adhesion was discussed in terms of the denaturation of plasma proteins upon adsorption, which was determined by Fourier‐transform infrared spectroscopy. With increasing degree of protein denaturation, the platelet adhesion and the serotonin release were enhanced. This relationship was particularly evident in the case of albumin adsorption. It was shown that the surface properties of substrate polymers affect the protein adsorption, which in turn influences the adhesion of platelets.
Analysis of A · W glass‐ceramic surface by micro‐beam X‐ray diffraction
Authors: Kitsugi Toshiaki , Yamamuro Takao , Kokubo Tadashi 
Published: December 2004

AbstractThe purpose of this study is to examine the formation of hydroxyapatite on the surface of glass‐ceramics (chemical composition: SiO2, 34.2; P2O5, 16.3; CaO, 44.9; MgO, 4.6; CaF2, 0.5 in weight ratio). Two experiments were performed. In the first experiment, plates (2 × 25 × 25 mm) of glass‐ceramics containing apatite‐wollastonite (designated A · W–GC) were used. In the second experiment, plates (15 × 10 × 2 mm) of A · W–GC and its parent glass (designated G) were used. In each experiment, two paired specimens of identical material, one tied with silk thread, the other not tied, were implanted subcutaneously into rats. In both experiments, bonding to each other of both tied and untied specimens was observed one month after implantation. A pattern resembling hydroxyapatite was identified on the detached surface of the bonded A · W–GC by micro‐beam x‐ray diffraction. The weak crystalline pattern was also observed on the detached surface of bonded G samples. Analysis of the interface by SEM‐EPMA showed that a calcium‐phosphorus rich layer formed between the two bonded surfaces in both experiments. It is suggested that the bonding between the two materials was formed by the calcium‐phosphorus rich layer, and that the calcium‐phosphorus rich layer is virtually identical to hydroxyapatite.
Tissue/biomaterial interface characteristics of four elastomers. A transmission electron microscopical study
Authors: Bakker D. , van Blitterswijk C. A. , Hesseling S. C. , Daems W. Th. , Grote J. J. 
Published: December 2004

AbstractThe tissue/biomaterial interface reactions of four elastomers—selected as candidates for scaffolding for tympanic membrane tissue in a total alloplastic middle ear prosthesis—were studied at the electron microscopical level after implantation in the rat middle ear. Time‐dependent changes in the phagocyte/polymer interface suggested degradation of porous implants made of Estane polyether urethane, polypropylene oxide, and a poly(ethylene oxide hydantoin) and poly(tetramethylene terephthalate) segmented polyether polyester copolymer (HPOE/PBT copolymer), but not of dense Silastic silicone rubber implants. Silastic was always encapsulated in fibrous tissue. Contact between fibrous tissue and HPOE/PBT copolymer or Estane was established in the third month, but fibrous tissue was never seen close to polypropylene oxide. Bone made contact only with Estane and HPOE/PBT copolymer implants. The bone/copolymer interface showed an electron‐dense layer morphologically similar to that seen between bone and hydroxyapatite ceramic, suggesting that with respect to bone HPOE/PBT copolymer behaves like a bioactive implant material. The electron‐dense layer was absent at the bone/Estane interface. Estane and especially HPOE/PBT copolymer seem to be suitable as alloplastic tympanic membrane because of their interface behavior with respect to fibrous tissue and bone.
Tissue response to percutaneous implants in rabbits
Authors: Jansen J. A. , van Der Waerden J. P. C. M. , van der Lubbe H. B. M. , de Groot K. 
Published: December 2004

AbstractThis study reports on certain aspects of wound‐healing around percutaneous implants. Plasma‐sprayed and dense hydroxylapatite, titanium, and carbon test implants were inserted into the tibia and the cranium of 12 rabbits. Four and 8 months after insertion, the animals were sacrificed and the implants with their surrounding tissues were processed histologically. Light‐ and transmission electron microscopic investigations were performed. It is found that direct and indirect boneanchoring favors the longevity of percutaneous implants. No differences in tissue reaction between the various implant materials were observed.
Surface modification of biomaterials through noble metal ion implantation
Authors: Buchanan R. A. , Lee In‐Seop , Williams J. M. 
Published: December 2004

AbstractStudies are described involving effects of noble‐metal ion implantation on corrosion inhibition and charge‐injection capabilities of surgical Ti‐6Al‐4V alloy. A major factor linked to excellent long‐term biological performance is resistance to metal‐ion release to tissues. The elements most resistant to corrosion in aqueous solutions are the noble metals. Disadvantages include expense and general inadequacy of mechanical properties. However, if small quantities can be used to surface‐modify a surgical device in the last stage of manufacture, that device could possess an optimum combination of environmental integrity, biological response, mechanical properties, and charge‐injection capability at miniumum expense. Results for ion‐implanted Ir are presented. Iridium has been described as the most corrosion‐resistant element known, and its activated oxide as having the highest charge‐injection capability of any material known. Ti‐6Al‐4V samples, ion implanted with 2.5 and 5.0 atomic % peak‐maximum concentrations of Ir, were subjected to corrosion treatments to enrich the surface with Ir. Corrosion potential and cyclic voltammetry measurements indicated enrichment in H2SO4, and continued enrichment in isotonic saline, with corrosion potentials approaching that of pure Ir, and charge densities in isotonic saline exceeding that of pure Ir for the 5.0% peak‐max Ir implanted material. X‐ray photoelectron spectroscopy confirmed the high levels of Ir surface enrichment.
Bactericidal properties of a titanium‐peroxy gel obtained from metallic titanium and hydrogen peroxide
Authors: Tengvall P. , Hörnsten E. G. , Elwing H. , Lundström I. 
Published: December 2004

AbstractA stable titanium‐peroxy‐radical complex is formed when metallic titanium interacts with hydrogen peroxide. The radical appears as one component in an aqueous gel formed when excess peroxides have been (catalytically) decomposed. The interaction between titanium and hydrogen peroxide may be of importance also in vivo during an inflammatory response at the implant. We report in this paper on the bactericidal effects of the titanium gel in the lacto‐ and myeloperoxidase–halogen systems. Escherichia coli viable count was used to evaluate the bactericidal properties of the gel and of H2O2 for comparison. The gel had only small or no toxic properties at high dilutions. Higher concentrations of the gel had bactericidal properties similar to those of H2O2. The results indicate that at physiological pH, the decomposition products of the gel are titanium hydroxide (Ti(IV)(OH−)4) and hydrogen peroxide (H2O2). It was found that the gel probably oxidizes glutathione directly in contrast to H2O2, which needs a peroxidase to do so. A model for the interaction between titanium and hydrogen peroxide is suggested. Its consequences for the properties of titanium in vivo are also discussed.
Ca, P‐rich layer formed on high‐strength bioactive glass‐ceramic A‐W
Authors: Kokubo T. , Ito S. , Huang Z. T. , Hayashi T. , Sakka S. , Kitsugi T. , Yamamuro T. 
Published: December 2004

AbstractGlass‐ceramic A‐W, containing crystalline apatite and wollastonite in a MgOCaOSiO2 glassy matrix shows high bioactivity as well as high mechanical strength, but other ceramics containing the same kinds of crystalline phases in different glassy matrices do not show the same bioactivity. In order to investigate the bone‐bonding mechanism of this type of glass‐ceramic, surface structural changes of the glass‐ceramics after exposure to simulated body fluid were analyzed with various techniques. A solution with ion concentrations which are almost equal to those of the human blood plasma was used as the simulated body fluid, instead of Tris‐buffer solution hitherto used. For analyzing the surface structural changes, thin‐film x‐ray diffraction was used in addition to conventional techniques. It was found that a bioactive glass‐ceramic forms a Ca, P‐rich layer on its surface in the fluid but nonbioactive ones do not, and that the Ca, P‐rich layer consists of carbonate‐containing hydroxyapatite of small crystallites and/or defective structure. These findings were common to those of Bioglass‐type glasses. So, we conclude that the essential condition for glass and glass‐ceramic to bond to bone is the formation of the surface apatite layer in the body environment but it is not essential to contain apatite within the material. Bioactivity of glass and glass‐ceramic can be evaluated in vitro by examining the formation of the surface apatite layer in the simulated body fluid described above.
Effect of alternative crosslinking methods on the low strain rate viscoelastic properties of bovine pericardial bioprosthetic material
Authors: Pereira Christoper A. , Michael Lee R. J. , Haberer Sean A. 
Published: December 2004

AbstractEarly failures of bovine pericardial heart valves have been due to leaflet perforation/tearing and calcification. Since glutaraldehyde fixation has been shown to produce marked changes in leaflet mechanics and has been linked to the development of calcification, alternative crosslinking techniques have been suggested as means to overcome these obstacles. We have examined the low strain rate viscoelastic behavior of bovine pericardium: (1) fresh; (2) chemically treated with glutaraldehyde, cyanimide, or polyglycidyl ether; or (3) physically treated by freeze‐drying or heat‐drying. Shrinkage temperature tests were conducted to assess intrahelical crosslinking. Polyglycidyl ether and glutaraldehyde both produced substantial crosslinking, with the shrinkage temperature rising above 80°C. Mechanical changes were nearly equivalent, both showing decreased stress relaxation and increased extensibility consistent with intrahelical crosslinking and shrinkage during fixation. Cyanimide, known to crosslink pure collagen materials, showed no evidence of crosslinking intact tissue. Heat‐drying, also effective in pure collagen preparations, produced an increase in UTS and tissue modulus, but otherwise left the tissue unchanged. Freeze‐drying had no mechanical effect, and therefore provides an attractive means for the storage of connective tissues for later mechanical testing.
Macroporous calcium phosphate ceramic for long bone surgery in humans and dogs. Clinical and histological study
Authors: Daculsi G. , Passuti N. , Martin S. , Deudon C. , Legeros R. Z. , Raher S. 
Published: December 2004

AbstractOur previous studies reported the performance of Macroporous Biphasic Calcium Phosphate (MBCP) in spine fusion. In the present study, this material was used in block forms in selected patients with tumoral resection in long bone. Two cases were chosen with large benign bone tumors. Clinical and radiographic assessments, CT scans, and NMR were performed after 16 months, and in one case control biopsies were taken. In order to understand the kinetic process of biodegradation of the MBCP blocks and bone formation at the expense of the ceramics, an experimental study in surgicaly created bond defects in canine femoral cortices was made. The MBCP blocks recovered after implantation period from 2 to 18 weeks were analyzed using histological, stereological, ultrastructural, electron microprobe, and IR spectroscopy analyses. This study demonstrated the efficiency of MBCP blocks for filling pathological defects in human long bone. The biointegration process of the MBCP blocks was due to a partial dissolution of the ceramics crystals (b‐TCP content) by multinucleated cells. Simultaneously, bone ingrowth at the expense of the ceramic is observed. The new bone formation inside the MBCP macropores and in the spaces between the blocks, involved the formation of a new cortical bone on the outer part, and a trabecularlike bone with bone marrow in the inner part of the implant. The biological resorption of the MBCP ceramic decreased after 1 month implantation in dog, due to the protective role of the newly formed lamellar bone on the surface and in the core of the ceramics.
The biocompatibility of hydroxyapatite ceramic: A study of retrieved human middle ear implants
Authors: van Blitterswijk C. A. , Hesseling S. C. , Grote J. J. , Koerten H. K. , de Groot K. 
Published: December 2004

AbstractThe biocompatibility of 11 hydroxyapatite auditory canal‐wall prostheses and 4 hydroxyapatite incus prostheses implanted for 4 to 40 months was evaluated by light microscopy, scanning electron microscopy, transmission electron microscopy, and Röntgen microanalysis. These 15 prostheses representing 4% of 375 prostheses, had been removed because of unresolved chronic middle ear infection, residual cholesteatoma, or poor fit. The findings confirmed earlier reports on the biocompatibility of hydroxyapatite in vitro, in animals, and in man. An electron‐dense layer was found at the interface with bone and fibrous tissue, and a firm bond between the ceramic and bone at the hydroxyapatite ceramic/bone interface developed. Macropores became filled with bone and fibrous tissue, and the tissue in the individual pores was interconnected. Furthermore the incus prostheses were covered with an epithelium similar to that found in the human middle ear. Findings diverging from those made in other studies were the relatively large amount of exudate in the pores, an apparent increase of degradation during infection, and the accumulation of trace elements in one of the canal‐wall prostheses. In all likelihood these three phenomena may be attributed to the unfavorable conditions to which these prostheses were exposed during implantation.
X‐ray diffraction studies on plasma‐sprayed calcium phosphate‐coated implants
Authors: Koch B. , Wolke J. G. C. , de Groot K. 
Published: December 2004

AbstractCalcium phosphate coatings on steel, obtained by the plasma‐spray technique, were examined by x‐ray diffraction in order to get some information on their crystallographic structure and crystallinity. Surface roughness values were also determined. These coatings are of interest for hip‐prosthesis materials in particular.
The behavior of alloplastic tympanic membranes in Staphylococcus aureus‐induced middle ear infection. I. Quantitative biocompatibility evaluation
Authors: Bakker D. , van Blitterswijk C. A. , Hesseling S. C. , Th. Daems W. , Kuijpers W. , Grote J. J. 
Published: December 2004

AbstractThe biocompatibility of dense Silastic implants and porous implants made of Estane 5714 F1 polyether urethane, polypropylene oxide, and an HPOE/PBT segmented polyether polyester copolymer was evaluated during an induced Staphylococcus aureus middle ear infection.The middle ear response to infection seemed not to be affected by the presence of implants made of either of the polymers. Light microscopical morphometry and transmission electron microscopy showed degradation of the porous implants under study, but not of Silastic implants, which were invariably surrounded by a fibrous capsule. This finding, combined with the degree of porous implant degradation, the composition of the tissues surrounding the implants, and the tissue/biomaterial interface reactions are consistent with the results obtained in the noninfected middle ear. Round‐cell infiltrates however, were predominantly associated with implants made of polypropylene oxide and HPOE/PBT copolymer; while the presence of (phagocytosed) microbial debris was associated with copolymer.The present findings indicate that with respect to implant behavior in infected surroundings Estane is the best porous material, whereas the behavior of Silastic implants did not deviate from that in noninfected ears.
Acrylated phosphonate esters containing 1,3‐dioxane and 1,3‐dioxolane moieties as adhesion‐promoting agents for dentin and hard tissues, I
Authors: Cabasso Israel , Sahni Suresh 
Published: December 2004

AbstractNovel acrylated phosphonate esters containing 1,3‐dioxane and 1,3‐dioxolane moieties derived from polyols such as glycerol, D‐mannitol, D‐sorbitol, pentaerythritol, and dipentaerythritol have been evaluated in vitro for their role as adhesion‐promoting agents in composites employed for restorative dentistry. Some of the acrylated phosphonate esters have been found to promote strong bonding to dentin; the dipentaerythritol derivative exhibits a bond strength of approximately 960 psi (7 MPa) which compares favorably to commercial dentin adhesive systems. The bonding agents appear to act in multifunctional ways: the phosphonate group of the monomer chelates the calcium ions of hydroxyapatite at the dentin surface, ethereal oxygen atoms of 1,3‐dioxolane or 1,3‐dioxane moieties interact with the proteinaceous content of collagen, and the methacrylic fragment copolymerizes concomitantly with the other comonomers of the restorative composite material. Methods of preparing radiopaque adhesionpromoting acrylated phosphonates are also discussed.
Solutions able to reproduce in vivo surface‐structure changes in bioactive glass‐ceramic A‐W3
Authors: Kokubo T. , Kushitani H. , Sakka S. , Kitsugi T. , Yamamuro T. 
Published: December 2004

AbstractHigh‐strength bioactive glass‐ceramic A‐W was soaked in various acellular aqueous solutions different in ion concentrations and pH. After soaking for 7 and 30 days, surface structural changes of the glassceramic were investigated by means of Fourier transform infrared reflection spectroscopy, thin‐film x‐ray diffraction, and scanning electronmicroscopic observation, in comparison with in vivo surface structural changes. So‐called Tris buffer solution, pure water buffered with trishydroxymethyl‐aminomethane, which had been used by various workers as a “simulated body fluid,” did not reproduce the in vivo surface structural changes, i.e., apatite formation on the surface. A solution, ion concentrations and pH of which are almost equal to those of the human blood plasma—i.e., Na+ 142.0, K+ 5.0, Mg2+ 1.5, Ca2+ 2.5, Cl− 148.8, HCO3− 4.2 and PO42− 1.0 mM and buffered at pH 7.25 with the trishydroxymethylaminomethane–most precisely reproduced in vivo surface structure change. This shows that careful selection of simulated body fluid is required for in vitro experiments. The results also support the concept that the apatite phase on the surface of glass‐ceramic A‐W is formed by a chemical reaction of the glass‐ceramic with the Ca2+, HPO42−, and OH− ions in the body fluid.
Preliminary characterization of bioresorbable and nonresorbable synthetic fibers for the repair of soft tissue injuries
Authors: Shieh Sheu‐Jane , Zimmerman Mark C. , Parsons J. Russell 
Published: December 2004

AbstractPreliminary characterizations of two new synthetic fibers were performed to determine their potentials for use in soft tissue scaffolding devices. A slowly bioresorbing random copolymer of dimethyltrimethylene carbonate (DMTMC) and trimethylene carbonate (TMC) was the first fiber evaluated. The second was a nonresorbable high‐strength synthetic fiber of highly oriented polyethylene. Their in vitro mechanical behavior was evaluated by loading fibers in uniaxial tension to determine mechanical properties in dry and wet (saline) environments. The polyethylene fiber had a dry strength of approximately 2.0 GPa, an ultimate strain of 3 to 4%, a tangent modulus of 57 GPa, and was not affected by the saline environment. The bioresorbable fiber had a dry strength of approximately 500 MPa, an ultimate strain of 35%, and tangent modulus of 5.4 GPa. The in vitro resorption of the bioresorbable fibers produced a 15% loss in strength over a 10‐week period. In vitro cell‐fiber compatibility studies were conducted to assay material biocompatibility and fiber substrate efficacy. Fibroblasts proliferated and migrated on both the polyethylene and bioresorbable fibers at rates similar to those previously found for other compatible fibers, thus demonstrating the new materials to be similar in their in vitro biocompatibility profiles. Morphological assessment with SEM also confirmed that these materials were suitable substrates for cell attachment. A rabbit Achilles tendon repair model using oriented polyethylene or bioresorbable fiber tows was evaluated after 12 and 26 weeks of implantation. The mechanical performances of both types of tendon repairs were similar to those found in previous studies using carbon or PET fibers. The polyethylene fibers elicited a low‐grade chronic inflammatory tissue response. The bioresorbable fibers were still intact at 26 weeks and remained relatively inert in the host tissue, eliciting a minimal foreign body response.