bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative studies by cell culture and in vivo implantation test on the toxicity of natural rubber latex materials
Authors: Ikarashi Yoshiaki , Toyoda Kazuhiro , Ohsawa Naomi , Uchima Takao , Tsuchiya Toshie , Kaniwa Masa‐Aki , Sato Michio , Takahashi Michihito , Nakamura Akitada 
Published: May 2005

AbstractColony assay using V79 cells, the agar diffusion assay with L929 cells, and the 7‐day rabbit muscle implantation test were employed to evaluate the cytotoxicity and tissue toxicity of natural rubber latex (NRL) materials. The in vivo implantation test showed that, among 13 histological parameters, thickness of inflammatory layer was the most useful index to evaluate tissue responses quantitatively. A comparison of the in vivo and in nitro parameters revealed the following correlations between the thickness of the inflammatory layer and cytotoxicity indices: Colony assay of the extracts, IC50: r = 0.80; Agar diffusion assay, Zone index: r = 0.73; Lysis index: r = 0.61. From these results, it appears that the colony assay provides a more reliable prediction of the tissue response than the agar diffusion assay.
Protein adsorption of biomedical polymers influences activated monocytes to produce fibroblast stimulating factors
Authors: Bonfield T. L. , Colton E. , Anderson J. M. 
Published: May 2005

AbstractThe studies presented in this manuscript were based upon the hypothesis that monocytes/macrophages selectively produce cytokines and growth factors due to their interactions with polymers and proteins which are adsorbed to their surfaces. These factors in turn selectively influence the ability of fibroblasts to proliferate. The factors which influence fibroblast proliferation were released from monocytes incubated with polymers: Biomer®, polydimethylsiloxane (PDMS), polyethylene (PE), expanded polytetrafluoroethylene (ePTFE), Dacron, and control polystyrene with and without preadsorption with physiological concentrations of IgG, fibrinogen, fibronectin, hemoglobin, or albumin. No simple correlation was found between adsorbed protein, biomedical polymer, and the ability monocytes to produce growth factors and cytokines which influence fibroblast proliferation. This is evidence for selective protein‐polymer interactions which turn selectively activate monocytes produce variable cell cycle competence and progression factors controlling fibroblast growth.
Development of FRP composite structural biomaterials: Ultimate strength of the fiber/matrix interfacial bond in in vivo simulated environments
Authors: Latour R. A. , Black J. 
Published: May 2005

AbstractFiber reinforced polymer (FRP) composites are being developed as alternatives to metals for structural orthopedic implant applications. FRP composite fracture behavior and environmental interactions are distinctly different from those which occur in metals. These differences must be accounted for in the design and evaluation of implant performance. Fiber/ matrix interfacial bond strength in a FRP composite is known to strongly influence fracture behavior. The interfacial bond strength of four candidate fiber/matrix combinations (carbon fiber/polycarbonate, carbon fiber/polysulfone, polyaramid fiber/polycarbonate, polyaramid fiber/ polysulfone) were investigated at 37°C in dry and in vivo simulated (saline, exudate) environments. Ultimate bond strength was measured by a single fiber‐microdroplet pull‐out test. Dry bond strengths were significantly decreased following exposure to either saline or exudate with bond strength loss being approximately equal in both the saline and exudate. Bond strength loss is attributed to the diffusion of water and/or salt ions into the sample and their interaction with interfacial bonding. Because bond degradation is dependent upon diffusion, diffusional equilibrium must be obtained in composite test samples before the full effect of the test environment upon composite mechanical behavior can be determined.
A comparative evaluation of the biostability of a poly (ether urethane) in the intraocular, intramuscular, and subcutaneous environments
Authors: Richard Christ F. , Buchen Shelley Y. , Fencil David A. , Knight Patricia M. , Solomon Kerry D. , Apple David J. 
Published: May 2005

AbstractA transparent poly (ether urethane) (PEU) was considered for use as a foldable intraocular lens material. The PEU was found to possess excellent mechanical, optical, and surface characteristics for this application. In uitro hydrolytic and ultraviolet aging studies suggested the PEU to be tolerant to conditions simulating 3–10 years of normal intraocular exposure. Different behavior was obtained, however, from intraocular and subcutaneous implantation of the PEU. After 6 months of intraocular exposure in the feline model, prototype PEU lenses had lost most or all of their optical resolving power. SEM analysis demonstrated scattered pitting and cracking on the lens surfaces. Degradation was found to be more extreme after as little as 30 days of subcutaneous exposure in rabbits. Severe pitting over the entire surface of implanted flat PEU specimens was observed by SEM. Macroscopic examination showed the samples to be frosty in appearance. It was postulated that the subcutaneous implant environment provides an accelerated in uivo model for materials intended for intraocular use. A minimum acceleration of 6–10X was estimated on a preliminary basis. The PEU studied here was found to be unsuitable for use as a foldable intraocular lens material.
Physical and biological properties of a new synthetic amino acid copolymer used as wound dressing
Authors: Eloy R. , Brack A. , Dorme N. , Cornillac A. M. 
Published: May 2005

AbstractAnew synthetic amino acid copolymer has been evaluated as wound covering. It is permeable to water vapor in the region of 4.1 kg/m2/24 h, it does not allow microbial proliferation after in vitro inoculation, it is impermeable to bacteria, and is stable and flexible. In vivo experiments were designed to provide qualitative and quantitative evaluation on its possible use as a skin substitute in full‐thickness skin excision in the guinea pig. Two excisions, approximately 12–;14 cm2 were performed on each side of the spine, leaving the panniculus carnosus. One site was treated with the membrane, the other with gauze. Each animal served as its own control. Photographs with a fixed focal‐length camera were taken in identical conditions for all wounds immediately and 7,14, and 21 days after excision. They were analyzed by planimetry. Histological studies were performed at 7,14, and 21 days. The rate of healing between 0 and 21 days of the wounds treated with the copolymer membrane was significantly accelerated in comparison with wounds covered with a dry dressing (p < 0.05). This increased epithelialization rate was confirmed by histology, which also suggested a reduction of the inflammatory response of the wound. In vivo biodegradation studies were also performed by subcutaneous implantation in the rat followed at 15, 30, 60, and 90 days by histology and physicochemical analyses. The results demonstrate that the membrane is not biodegradable.
Development and use of a parallel‐plate flow chamber for studying cellular adhesion to solid surfaces
Authors: van Kooten T. G. , Schakenraad J. M. , Van der Mei H. C. , Busscher H. J. 
Published: May 2005

AbstractA parallel‐plate flow chamber is developed in order to study cellular adhesion phenomena. An image analysis system is used to observe individual cells exposed to flow in situ and to determine area, perimeter, and shape of these cells as a function of time and shear stress. With this flow system the behavior of human fibroblasts spread on glass is studied when exposed to an increasing laminar flow. The flow system appears to be well‐suited for following individual cells during detachment. After 75 to 90 min, at a shear stress of 350 dynes/cm2, more than 50% of the spread cells are detached from the surface. Cells with higher spreading areas stay longer at the glass surface. Cells round up before detaching. Sometimes the cell body is attached to the substratum through a thin filament during detachment. At the scanning electron microscopy level numerous filopodial extensions are observed. Cell material could only rarely be observed at the light or scanning electron microscopic level on the substratum once a cell was detached.
Effect of local hemostatics on bone induction in rats: A comparative study of bone wax, fibrin–collagen paste, and bioerodible polyorthoester with and without gentamicin
Authors: Solheim Eirik , Pinholt Else Marie , Bang Gisle , Sudmann Einar 
Published: May 2005

AbstractLocal hemostatics for osseous tissue should preferably be absorbable and biocompatible and should not inhibit osteogenesis. The tissue response and effect on demineralized boneinduced heterotopic osteogenesis in the abdominal muscle of 120 male Wistar rats by different local hemostatics were evaluated by light microscopy and 85Sr uptake analyses. Nonabsorbable bone wax of 88% beeswax and absorbable bovine fibrin–collagen paste both significantly inhibited o st eoinduction, whereas a bioerodible polyorthoester drug delivery system with or without 4% gentamicin did not. Bone wax was not absorbed and induced a chronic foreign body reaction. Fibrin–collagen paste induced less inflammation with numerous monocytes and macrophages with engulfed material. Bioerodible polyorthoester caused a very moderate tissue reaction and was mostly resorbed at week 4.
Stimulation of neutrophil movement by metal ions
Authors: Hunt J. A. , Remes A. , Williams D. F. 
Published: May 2005

AbstractThe interaction between corrosion products of metallic implants and the surrounding tissue is important in determining the biocompatibility of the implant, in particular the interaction of corrosion products with inflammatory cclls such as neutrophils and macrophages. Such cells are capable of releasing enzymes and high‐energy oxygen radicals which can damage the tissue. Clearly, any factors that influence cell movement to the implant site could influence the biocompatibility of the implant. The present study examined the influence that copper and nickel ions had on neutrophil locomotion. Both copper and nickel ions stimulated a proportion of the neutrophil population to take up a nonspherical morphology and to locomote. These metal ion stimulated cells have higher circularity values and move slower than neutrophils incubated with FM1.P. For both FMLP and nickel ion stimulated cells, there is a correlation between the speed of neutrophil locomotion and neutrophil circularity; as the neutrophil circularity value decreases, the speed of locomotion increases.
Cytokine and growth factor production by monocytes/macrophages on protein preadsorbed polymers
Authors: Bonfield T. L. , Colton E. , Marchant R. E. , Anderson J. M. 
Published: May 2005

AbstractThese studies evaluate the effect of biomedical polymers: Biomer, polydimethylsiloxane (PDMS), polyethylene, expanded polytetraf luoroethylene (ePTFE), Dacron, and the control polystyrene with or without adsorbed proteins IgG, fibrinogen, and fibronectin on the ability of activated human monocytes/macrophages to produce Interleukin 1 Beta (IL‐1‐B), Interleukin 6 (IL‐6), and Tumor Necrosis Factor Alpha (TNF‐A). Monocytes/macrophages incubated on biomedical polymers with or without protein preadsorption produce variable levels of IL‐1‐B, IL‐6, and TNF‐A dependent on the polymer and adsorbed protein. IL‐6 was produced in the greatest quantity and was the most influenced by protein adsorption. ePTFE and PDMS polymers were least stimulating while polystyrene was the most stimulating of monocyte activity. Adsorbed IgG consistently altered the ability of the polymers to activate monocytes/macrophages to produce cytokines. These studies provide important insight into conditions which modulate monocyte/macrophage activity in response to protein preadsorbed biomedical polymers.
Adhesive bone cement containing hydroxyapatite particle as bone compatible filler
Authors: Ishihara Kazuhiko , Arai Jorplo , Nakabayashi Nobuo , Morita Sadao , Furuya Kotaro 
Published: May 2005

AbstractAcrylic bone cement containing hydroxyapatite (HA) as a filler was developed using 4‐methacryloyloxyethyl trimellitate anhydride (4‐META) to promote adhesion both to bone and HA. The mechanical strengths of the cement did not decrease significantly with increasing HA in the cement by 4‐META. However, strengths decreased with increasing HA content in the absence of 4‐META. Scanning electron micrographic examination of fractured surfaces of the cement clearly showed that the HA particles adhered to the matrix resin when 4‐META was added. Thus, it was important to maintain the original mechanical strengths for 4‐META. The HA particles along the surface increased with increased HA content in the cement. The cement adhered to bone with a tensile bond strength was higher than 10 MPa.
Thrombin and albumin adsorption to PVA and heparin–PVA hydrogels. I. Single protein isotherms
Authors: Smith Barbara A. H. , Sefton Michael V. 
Published: May 2005

AbstractMore radiolabeled thrombin was adsorbed to heparin‐polyvinyl alcohol (PVA) than to PVA, consistent with a specific interaction with the immobilized heparin. The maximum surface concentration on heparin‐PVA was estimated to be ∼450 nmol/m2 with an apparent affinity constant (Ka,) of 2.5μM−1; on PVA, the plateau concentration was 10 nmol/m2 with a Ka < 1 nM−1. There was little difference in bovine serum albumin (BSA) adsorption between PVA and heparin PVA. Interestingly, thrombin adsorption to polyethylene was indistinguishable from that to PVA despite the large difference in surface chemistry. BSA adsorbed to polyethylene with higher affinity than to the hydrogels, although the plateau concentrations were comparable. The adsorbed thrombin was biologically inactive at least towards chromogenic substrate, with the residual activity on PVA unaffected by subsequent incubations with antithrombin 111. PVA and heparin‐PVA presented a heterogeneous and complex substrate for interaction with proteins. The adsorbed protein was likely present in multiple states depending on the groups with which it interacted.
Short‐term response of brain tissue to cerebrospinal fluid shuntsin vivoandin vitro
Authors: Del Bigio Marc R. , Fedoroff Sergey 
Published: May 2005

AbstractThe purpose of the studies was to determine how gross physical characteristics of cerebrospinal fluid (CSF) shunts and the cellular proliferative response to shunts contribute to shunt obstruction. Ventricular catheters with round holes, slots, and flanges were implanted into the lateral ventricles of rabbits for 4 weeks. All shunt designs were subject to ingrowth of tissue from the ventricle wall or choroid plexus. There were no qualitative or quantitative differences between normal and hydrocephalic rabbits. Astroglial cells from newborn mice were cultured on shunt catheters for 2 or 4 weeks, The growth of these cells was poor, probably because the cells cannot attach well to the silicone rubber substrate. Contact between the shunt catheter and vascularized brain tissue is the most important factor in the genesis of shunt obstruction. © 1992 John Wiley & Sons, Inc.
Influence of calcium concentration on the dentin wettability by an adhesive
Authors: Panighi M. , G′Sell C. 
Published: May 2005

AbstractPlane dentin surfaces were abraded perpendicular to the radicular axis of sound human molars. They were cleaned to reveal the tubules, and the morphological features of each surface were studied microscopically. For a first series of teeth, the Vickers microhardness of the dentin surfaces was measured and the calcium and phosphorus composition was determined by electron microprobe analysis. For a second series, the microhardness and wettability of the surface by the Scotchbond adhesive were compared. Positive correlations were found between the following parameters: degree of minerality, dentin compactness, hardness, and spreading capability of the adhesive.
Interactions of thermally denatured fibrinogen on polyethylene with plasma proteins and platelets
Authors: Rubens Fraser , Brash John , Weitz Jeff , Kinlough‐Rathbone Raelene 
Published: May 2005

AbstractDuring the investigation of fibrin deposition onto hydrophobic polymers in contact with human blood, a model was developed in which fibrinogen was denatured and irreversibly coated onto a polyethylene surface by heating to 70°C for 10 min. The denatured fibrinogen‐polyethylene surface is resistant to fluid wall shear rates of up to 550 s−1 and the fibrinogen does not desorb in the presence of plasma proteins. Compared to uncoated polyethylene, little albumin or fibrinogen adsorbs to heat‐denatured fibrinogen. Thrombin binds to the denatured fibrinogen‐coated polyethylene with low affinity and also acts on the surface‐bound denatured fibrinogen and cleaves fibrinopeptide A (FPA) quantitatively. Washed, 51Cr‐labeled platelets do not adhere to the thermally denatured fibrinogen at either low or high shear rates compared to surfaces coated with undenatured fibrinogen (p < 0.01). These observations support the role of the D domain of fibrinogen in platelet adhesion because this is the region that is denatured by heating. In contrast, the E domain of fibrinogen is not altered by heating to 70°C and hence remains susceptible to thrombin and/or plasmin cleavage. The characteristics of this surface are such that it can be used to develop fibrin‐coated surfaces for use in studies of thrombus formation on artificial surfaces. © 1992 John Wiley & Sons, Inc.
Porosity of porcine small‐intestinal submucosa for use as a vascular graft
Authors: Hiles M. C. , Badylak S. F. , Geddes L. A. , Kokini K. , Morff R. J. 
Published: May 2005

AbstractThe porosity of a vascular graft material has been suggested as a major factor affecting the rate and degree of neovascularization of newly implanted grafts, with higher porosites generally associated with better performance. The objective of this study was to determine the water porosity of a new vascular graft material, small‐intestinal submucosa (SIS), and to compare the values to those reported for other common vascular graft materials. In addition, the porosity of SIS was investigated with respect to applied pressure and applied uniaxial tension. Both rectangular, flat specimens and tubular specimens of SIS were subjected to static water pressure, and water was collected as it passed through the SIS material. SIS has a typical porosity of 0.52 mL/min · cm−2 at an applied pressure of 120 mm Hg. Although porosity appeared to be unaffected by uniaxial tension, it increased in proportion to applied pressure at a rate of 4.8 × 10−3 mL/min · cm−2/mm Hg. Theselow porosity values and the past success of SIS as a vascular graft material suggest that high‐porosity materials are not required for implant succes. © 1993 John Wiley & Sons, Inc.
Competitive adsorption of albumin against collagen at solution–air and solution–polythylene interfaces
Authors: Baszkin A. , Boissonnade M. M. 
Published: May 2005

AbstractThe adsorption of human serum albumin (HSA) from the binary mixtures with collagen was monitored at solution–air and solution–polyethylene interfaces by the in situ measurements. The results clearly demonstrate that on both interfaces albumin is the only adsorbing protein within a large collagen solution concentration range. At the albumin concentration equal to 0.005 mg/mL, the presence of collagen in solution results in the enhancement of albumin adsorption at solution‐air interface relative to its adsorption from the single protein system. The same phenomenon is manifested at the solution‐polyethylene interface, although the increase in albumin adsorption at this interface occurs at the albumin concentration equal to 0.01 mg/mL. These results are attributed to the lowering in the solution–air and solution–polyethylene interfacial tensions, and thus to the increase in the spreading characteristics of albumin in the presence of collagen molecules. The desorption experiments carried out with a buffer solution on polyethylene surfaces reveal the irreversibility of adsorbed albumin from both the single and the binary mixtures with collagen. When after 20 h of adsorption from the solutions containing albumin only, collagen was added to these solutions or when the samples after that period of time were first rinsed with a buffer and then with a collagen solution, the amounts of albumin remaining at the surfaces were in both cases reduced by one‐half. © 1993 John Wiley & Sons, Inc.
Hydrolytic degradation and morphologic study of poly‐p‐dioxanone
Authors: Lin Hui Ling , Chu C. C. , Grubb D. 
Published: May 2005

AbstractThein vitrohydrolytic degradation of 2‐0 size PDS monofilament suture was studied for the purpose of revealing its morphologic structure and degradation mechanism. The sutures were immersed in phosphate buffer of pH 7.44 for up to 120 days at 37°C. These hydrolyzed sutures were examined by the changes in tensile properties, weight, thermal properties, x‐ray diffraction structure, surface morphology, and dye diffusion phenomena. It was found that hydrolysis had significant effects on the change of PDS fiber morphology and properties. Hydrolysis, however, had no significant effect on overall molecular orientation of the fiber until the very late stage. PDS suture fibers retained their skeleton throughout the earlier periods of hydrolysis concurrent with mass and tensile strength losses. PDS sutures exhibited an absorption delay of 120 days. Both heat of fusion and melting point exhibited a maximum function of hydrolysis time. Hydrolysis of PDS suture fibers proceeded through two stages: random scission of chain segments located in the amorphous regions of microfibrrils and intermicrofibrillar space, followed by stepwise scission of chain segments located in the crystalline regions of microfibrils. Dye diffusion data showed that the passage along the longitudinal direction of the fiber was relatively easier than the lateral direction as evident in the diffusion coefficient, activation energy, and flexibility of chain segments. Swiss‐cheese model of fiber structure appears to describe the observed dye diffusion phenomena and their dependence on hydrolysis time and dying temperature. © 1993 John Wiley & Sons, Inc.
Surface atomic and domain structures of biomedical carbons observed by scanning tunneling microscopy (STM)
Authors: Feng L. , Andrade J. D. 
Published: May 2005

AbstractSTM has been used to study the surface domain and atomic structures of three biomedical carbons: glassy carbon (GC), low‐temperature isotropic carbon (LTI), and ultra‐low‐temperature isotropic carbon (ULTI). The images show atomic lattices on both GC and LTI, but not on ULTI. The lattices contain many defects; lattices in GC are more ordered than those in LTI. The images also show patchlike carbon crystallites with sizes of 3–15 nm for GC, 2–8 nm for LTI, and 1–3 nm for ULTI. The crystallites form surface domains that may differ in surface properties due to different orientations of the crystallites. Mechanical polishing makes the LTI surface more amorphous and more homogeneous. Based on the STM observations, we evaluate several hypotheses on the blood compatibility of biomedical carbons. © 1993 John Wiley & Sons, Inc.