bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rabbit eye irritation caused by wearing toxic contact lenses and their cytotoxicities: In vivo/in vitro correlation study using standard reference materials
Authors: Tsuchiya Toshie , Arai Tadashi , Ohhashi Jyunichi , Imai Kiyoshi , Kojima Hajime , Miyamoto Satoru , Hata Hideyo , Ikarashi Yoshiaki , Toyoda Kazuhiro , Takahashi Michihito , Nakamura Akitada 
Published: May 2005

AbstractTo clarify the relationship between eye irritancy and cytotoxic potential induced by irritant materials, we made lenses coated with standard reference materials (SRMs) prepared from various amounts of zinc diethyldithiocar‐bamate (ZDEC) and polyurethane (PU).Zinc diethyldithiocarbamate was classified as a mild irritant by the Draize eye irritation test. When ZDECSRM coated contact lenses were applied to rabbit eyes, Draize scores increased in proportion to both the ZDEC and PU concentrations used for coating. Furthermore, correlation with the cytotoxic potential (γ = −0.93) was better than with lactate dehydrogenase (LDH) activities of tears from rabbit eyes wearing these coated lenses (γ = 0.78). In conclusion, in vivo eye irritancy induced by wearing lenses could be estimated quantitatively with the cytotoxic potentials using a colony assay. Further‐more, we could compare different sensitivities caused by the same set of SRMs among three different sites of tissue. As a result, the order of sensitivity was eye > muscle ≫ skin. © 1993 John Wiley & Sons, Inc.
Cell growth on immobilized cell growth factor. 6. Enhancement of fibroblast cell growth by immobilized insulin and/or fibronectin
Authors: Ito Y. , Inoue M. , Liu S. Q. , Imanishi Y. 
Published: May 2005

AbstractA cell growth factor protein (insulin) and/or a cell‐adhesion protein (fibronectin) were immobilized on surface‐hydrolyzed poly(methyl methacrylate) membranes. The growth of mouse fibroblast cells STO was accelerated by the immobilized insulin. This acceleration was enhanced by introduction of spacer arms. Coimmobilization of insulin and fibronectin was very effective for the acceleration of cell growth. © 1993 John Wiley & Sons, Inc.
Cell growth on immobilized cell growth factor. 9. Covalent immobilization of insulin, transferrin, and collagen to enhance growth of bovine endothelial cells
Authors: Liu Shu Qin , Ito Yoshihiro , Imanishi Yukio 
Published: May 2005

AbstractBovine endothelial cells were cultivated on the surface of polyurethane membranes or tubes immobilized with insulin, transferrin, and/or collagen, and growth was measured. For the purpose of immobilization, amino groups were introduced on the membranes or tubes by glow‐discharge treatment in the presence of ammonia gas. The proteins were coupled to the amino groups on the surfaces by using dimethyl suberimidate (DMS) or water‐soluble carbodiimide (WSC). Growth of bovine endothelial cells was higher on immobilized insulin or transferrin using DMS than that using WSC. The cell growth was higher on immobilized insulin or transferrin than on free insulin or transferrin, respectively. Though immobilized collagen did not affect the cell growth, coimmobilization with insulin or transferrin brought about greater acceleration of cell growth. In addition, the immobilized collagen was indispensible to maintain the endothelial cells on the material surface for a long time. The endothelial cells grown in the polyurethane tubes, on which insulin and collagen are coimmobilized, kept a normal cobblestone‐like appearance and maintained the ability to secrete prostacyclin for 9 months. © 1993 John Wiley & Sons, Inc.
Selective neuronal cell attachment to a covalently patterned monoamine on fluorinated ethylene propylene films
Authors: Ranieri John P. , Bellamkonda Ravi , Jacob Jules , Vargo Terrence G. , Gardella Joseph A. , Aebischer Patrick 
Published: May 2005

AbstractThe patterned covalent surface addition of a monoamine to fluorinated ethylene propylene films (FEP) controls both cellular attachment and differentiation in defined media conditions. A radio frequency glow discharge (RFGD) process was used to replace FEP surface fluorine atoms with hydroxyl groups. The primary amine was then covalently attached by polymerizing aminopropyl‐triethoxysilane (APTES) via the hydroxyl functionalities. The selective attachment of cells to the APTES regions was determined to be dependent upon the initial adsorption of albumin to the patterned FEP membrane. Albumin was determined to enhance cellular attachment to the APTES regions and prevent attachment to the unmodified FEP areas for both an NB2a neuroblastoma cell line and primary rat endothelial cells. If albumin were not preadsorbed onto the membrane, selective attachment to the modified regions would not occur. Radiolabeling albumin with 125I demonstrated the preference of albumin for adsorption onto the monoamine surface where the cells preferentially attached. Both hydrophobic and ionic forces contributed to the adsorption process. Although selective cellular attachment to the patterned APTES regions could be achieved by albumin preadsorption to the surface, the neuroblastoma cells did not significantly differentiate unless additional serum components were supplemented to the media. © 1993 John Wiley & Sons, Inc.
Dissolution, leaching, and Al2O3 enrichment at the surface of bioactive glasses studied by solution analysis
Authors: Andersson Ö. H. , Rosenqvist J. , Karlsson K. H. 
Published: May 2005

AbstractFive glass compositions in or near the bioactive region in the system SiO2Na2OCaOP2O5Al2O3 were studied in vitro by immersion in Tris buffer. The Si concentration can be taken as a measure of the amount of dissolved glass, whereas the Na concentration can be used to estimate the thickness of the Si‐rich (Si gel) layer. Upon immersing a bioactive glass into Tris buffer, a surface layer of a few micrometer thickness is dissolved during the first 8 h. During the first few hours of immersion, the rate of dissolution of the glass network is equal to or exceeds that of the growth of the Si‐rich layer. If the glass contains Al2O3, most of the aluminum that would be released due to dissolution of the silica network is enriched in the Si‐rich surface layer that forms due to leaching. Al2O3 is not only bonded by the Si gel but also interferes with formation of culcium phosphate. © 1993 John Wiley & Sons, Inc.
Determination of the 3‐D morphology of degradable biopolymer implants undergoing in vivo resorption
Authors: Schliephake H. , Klosa D. , Rahlff M. 
Published: May 2005

AbstractA technique is presented that allows the visualization of the degradation process of biopolymers. Serial thick‐section specimens containing cross‐sections of polydioxanone implants (PDAs) were realigned for 3‐D reconstruction using a double‐embedding technique. The outlines of the cross‐sectioned implants were traced using an automatic image analysis system and converted into x, y, and z coordinates. The reconstruction of the implant body was achieved by the stepwise analysis of vertical relationships between two adjacent section levels. The surface was approximated by triangulation and calculated from the surface triangles. Visualization was achieved by introducing the data into commercially available software using z‐buffering and Gouraud shading. The geometric precision of the reembedding technique was found to be 0.8–1.5% of the screen width; recovering experiments showed a good approximation to the actual physical volume of unresorbed implants (±2.6%). The error of volume determination due to the limited resolution in the z direction was calculated to be acceptable (<5.0%) in isotropic objects where the ratio between the radius of the surface curvature and the distance between the sections is >4. Results indicate that large devices of PDAs are degraded in vivo in a fashion similar to that previously described for in vitro degradation of PLA molded screws by a surface/center differentiation with formation of hollow residuals after 17 weeks and complete degradation with phagocytosis of microparticles after 26 weeks. © 1993 John Wiley & Sons, Inc.
Apatite formation on three kinds of bioactive material at an early stage in vivo: A comparative study by transmission electron microscopy
Authors: Neo M. , Nakamura T. , Ohtsuki C. , Kokubo T. , Yamamuro T. 
Published: May 2005

AbstractApatite formation on the surface of three kinds of bioactive material at an early stage after implantation in bone was studied using transmission electron microscopy (TEM). The materials were apatite‐ and wollastonite‐containing glass‐ceramic (A‐W GC) as a surface‐active glass‐ceramic, dense sintered hydroxyapatite (HA) as a surface‐active ceramic, dense sintered β‐tricalcium phosphate (β‐TCP) as a resorbable ceramic. Particles of these materials, ranging from 100–300 μm in diameter, were implanted into rat tibviae, and specimens were prepared at 3, 7, 10, and 14 days after implantation. For A‐W GC, dissolution of the glassy and probably wollastonite phase was observed in the surface region on and after the third day, and a collagen‐free thin apatite layer on the surface of the material was evident on and after the seventh day. This apatite layer was observed before the mineralization of the surrounding bone matrix and was sometimes evident even where the material bordered on the bone marrow. On and after the tenth day, the surrounding bone matrix calcified and A‐W GC‐bone bonding through an apatite layer was completed. For HA, a mineralized collagen‐free layer was observed on the surface of the ceramic on and after the tenth day. This layer was always present near calcifying bone and it was difficult to distinguish from immature bone. For β‐TCP, such a surface mineralized layer was rarely evident, even just before bone‐ceramic contact, and finally the bone bonded to β‐TCP directly. Cell‐mediated degradation of β‐TCP was frequently observed. In conclusion, surface apatite formation differed among these materials, reflecting their bioactivity and suggesting differences in their bone‐bonding mechanisms. © 1993 John Wiley & Sons, Inc.
In vivo transport and excretion of corrosion products from accelerated anodic corrosion of porous coated F75 alloy
Authors: Brown Stanley A. , Zhang Kan , Merritt Katharine , Payer Joe H. 
Published: May 2005

AbstractCorrosion of porous coated cobalt chromium specimens surgically implanted subcutaneously in hamsters was accelerated by application of a fixed anodic potential. Corrosion current measurements were utilized for prediction of metal ion release based on Faraday's law. Daily urine samples were collected pre‐ and post‐stimulation, and, at animal sacrifice, organs and blood samples were taken for chemical analysis. By using in vitro release data from previous studies, and efficiency correction factors, the amount of metal ion release was calculated. The results demonstrated rapid and complete excretion of nickel and molybdenum. Most of the cobalt was excreted, with elevation of cobalt levels in liver, kidney, and lung. Chromium excretion was much lower due to significant red cell binding and in vivo storage, especially in the kidney and spleen. © 1993 John Wiley & Sons, Inc.
Effects of hydroxyapatite implants on primary mineralization during rat tibial healing: Biochemical and morphometric analyses
Authors: Schwartz Z. , Braun G. , Kohavi D. , Brooks B. , Amir D. , Sela J. , Boyan B. 
Published: May 2005

AbstractThe effect of 40‐ to 60‐mesh hydroxyapatite (HA) granules (Calcitek, Inc., Carlsbad, CA) on the process of primary mineralization during bone healing was examined following insertion of the HA granules into rat tibial bone after marrow ablation. Response to HA was assessed by monitoring morphometric and biochemical changes in matrix vesicles, which are extracellular organelles associated with initial calcification. Following insertion of HA, matrix vesicle‐enriched membranes (MVEMs) were isolated from the tissue adjacent to the implant and from the endosteum of the contralateral limb at 3,6,14, and 21 days and from a nonimplanted control group (t = 0). MVEM alkaline phosphatase‐ and phospholipase A2‐specific activities were increased on days 6 (peak) and 14; phosphatidylserine content was also elevated on days 6 and 14 (peak). Comparable changes were seen in the contralateral limb but at lesser magnitudes. Morphological changes were observed as well. The number of matrix vesicles/μm2 matrix increased on days 6 (peak) and 14. The mean diameter of the matrix vesicles was elevated on days 6 (peak), 14, and 21. Mean distance from the calcifying front increased on day 6 but was decreased on days 14 and 21. These results indicated that HA behaves like bone‐bonding implants in that there is a stimulation of matrix vesicle enzymes, increased phosphatidylserine content, and increase numbers of matrix vesicles. However, the increases occur only after 6 days postimplantation, indicating a delay in response when compared to normal healing. This delay is confirmed by the morphometric measurements. HA causes a reduction in the response associated with marrow ablation. In addition, the effects of HA are comparable locally and systemically but with different intensity. These observations suggest that osteogenic cells are able to compensate for the inhibitory effects of HA and primary calcification involves normal matrix vesicle production and maturation, if somewhat delayed and reduced in magnitude. The ability to support primary mineral formation may contribute to the successful bonding of HA with surrounding osseous tissue. © 1993 John Wiley & Sons, Inc.
Magnitude and polarity of a fluoroethylene propylene electret substrate charge influences neurite outgrowth in vitro
Authors: Makohliso Solomzi A. , Valentini Robert F. , Aebischer Patrick 
Published: May 2005

AbstractPositively charged coating materials such as polylysine improve neuronal attachment in vitro. Due to the structural complexity of these charged molecules, it is unclear whether neuronal effects are due to charge or to physicochemical effects, or both. Polymeric materials with charge storage capabilities and defined surface properties may provide a model in which electrical charge and surface property effects can be separated. Fluorinated ethylenepropylene (FEP) films can store negative or positive charges injected through a corona charging process, thus generating a negative or positive external electrostatic field. In the present study, mouse neuroblastoma (Nb2a) cells were cultured on positive, negative, and uncharged FEP substrates, in both serum‐containing and serum‐free media. Cell attachment, differentiation, and neurite outgrowth were assessed 24, 48, 72 and 96 h after plating. Electron spectroscopy for chemical analysis (ESCA), contact angle analysis, and scanning electron microscopy (SEM) revealed no differences in surface chemistry and topography between positive, negative, and uncharged FEP. No significant differences in the levels of cell attachment on positive, negative, and uncharged substrates were observed. Significantly higher levels of neurite outgrowth, however, were observed with positive substrates as compared to negative and uncharged substrates, in both media conditions. Substrates charged to +1000 V showed greater levels of outgrowth compared to +500 and +3000 V, suggesting the presence of an optimal range of charge for neurite outgrowth. These results show that cell/charge interactions mediate cell effects on electrically charged substrates with identical surface chemistry, topography and adhesivity. © 1993 John Wiley & Sons, Inc.
Effect of the conformation and orientation of adsorbed fibronectin on endothelial cell spreading and the strength of adhesion
Authors: Iuliano Denise J. , Saavedra Steven S. , Truskey George A. 
Published: May 2005

AbstractThe effect of surface hydrophobicity upon the conformation of the cell binding domain of fibronectin (Fn) and the influence of Fn conformation on bovine aortic endothelial cell (BAEC) adhesion were examined. The free sulfhydryl group of Fn located near the cell binding domain was selectively labeled with acrylodan, a polarity sensitive fluor. Fluorescence emission was monitored in solution and upon adsorption to hydrophilic glass and hydrophobic silanized glass. The acrylodan‐labeled Fn emission maximum shifted to longer wavelengths upon adsorption and the shift was greater for acrylodan‐labeled Fn adsorbed to hydrophilic glass than hydrophobic silane, suggesting that the acrylodan was in a more solvent accessible environment on glass than silane. BAEC, suspended in serum‐free medium, attached for 15 or 120 min onto glass or silane surfaces containing preadsorbed Fn, after which cell spreading and the strength of adhesion in a parallel plate flow chamber were measured. Cell spreading was similar on both surfaces after 15 min attachment, but BAECs were more spread on glass than silane after 120 min. At low surface concentrations of Fn, BAECs were more adherent on glass than silane. At higher surfaces concentrations, adhesion was similar. After a 2‐h incubation in serum‐free medium, cells on glass showed more extensive development of focal contacts as determined by immunofluorescent staining for vinculin. Cell adhesion under flow was reduced on silane by inhibition of protein synthesis with cycloheximide, suggesting that cell attachment to silane was promoted by cellular synthesis of Fn. The results indicate that changes in the conformation of the Fn cell binding domain affect Fn affinity for its cell surface receptor. © 1993 John Wiley & Sons, Inc.
Platelet‐mediated adhesion of Staphylococcus epidermidis to hydrophobic NHLBI reference polyethylene
Authors: Wang I‐Wen , Anderson James M. , Marchant Roger E. 
Published: May 2005

AbstractThe effects of platelets and plasma proteins on the adhesion of Staphylococcus epidermidis strain RP62A to hydrophobic NHLBI reference polyethylene was quantitatively studied using a rotating disk system to generate well‐defined shear conditions simulating the hemodynamics of human blood circulation. Bacterial adhesion was quantified by adhesive coefficient, the percentage of bacteria transported to the surface that becomes adherent. The results showed that surface modification by adsorption of plasma proteins reduced the adhesion of S epidermidis as compared to the bare polymer surface. This surface modification was not sufficient to eliminate completely bacterial adhesion, even at the highest physiologic shear stress level. S epidermidis did adhere strongly to polyethylene surface modified by platelets. This is readily evident as approximately 50% of the adherent S epidermidis were bound to contact‐activated platelets which occupied only 4% of the surface area. Adhesive coefficients to platelets were significantly greater than to the protein‐adsorbed polyethylene surface by at least one order of magnitude (P ≤ .01) across the range of physiological shear conditions investigated. These studies show that it is biologic surface modification by contact‐activated platelets, and not plasma proteins, which mediates S epidermidis adhesion to polyethylene. © 1993 John Wiley & Sons, Inc.
Production of prostacyclin and fibrinolysis modulators by endothelial cells cultured in the presence of polyethylene terephthalate
Authors: Cenni Elisabetta , Ciapetti Gabriela , Cavedagna Daniela , Di Leo Alessandro , Pizzoferrato Arturo 
Published: May 2005

AbstractThe aim of this study was the evaluation of the in vitro production of prostacyclin, and of tissue plasminogen activator (tPA) and its inhibitor, PAI‐1, by human endothelial cells cultured in the presence of polyethylene terephthalate (PET). After a 48 h contact between the cells and the polymer, the concentration of 6‐keto‐PGF1α, a stable metabolite of prostacyclin, tPA, and PAI‐1, was assayed on the supernatants. Contact of the endothelial cells with PET produced a highly significant reduction of 6‐keto‐PGF1α with respect to control cultures. Tissue plasminogen activator concentration in the supernatants of the cultures in contact with the material was similar to that observed in the controls, while PAI‐1 production was significantly reduced. It can be concluded that the contact between endothelial cells and PET determines a reduction in the platelet aggregability and an increase of the fibrinolytic activity due to a decrease in PAI‐1, while tPA concentration remains unchanged. © 1993 John Wiley & Sons, Inc.
Prosthetic replacement of the rabbit medial meniscus
Authors: Messner Karola , Gillquist Jan 
Published: May 2005

AbstractImplants of polyurethane‐coated polyester (Dacron), polyurethane‐coated PTFE (Teflon), or uncoated PTFE were used to substitute the medial rabbit meniscus, and were observed over a 3‐month period. Joint mechanics were similar for sham‐operation, meniscectomy, or substitution with a coated implant. Joints with an uncoated PTFE prosthesis tended to be less compliant and to show greater load dissipation during relaxation. Cartilage indentation showed softening with all alternatives compared to sham‐operation. Ingrowth into the prosthesis periphery was best with the PTFE implants. Both types of coated prosthesis retained their original shape, in contrast to the uncoated prostheses. To the naked eye the cartilage appeared unaffected only after sham‐operation or implantation of a coated PTFE prosthesis. Osteophyte formation was common with all alternatives except sham‐operation. We conclude that replacement of the medial meniscus with coated prostheses, especially the PTFE, was better than meniscectomy or using the uncoated prosthesis. However, cartilage softening and osteophyte formation indicate that joint mechanics were not restored to normal. © 1993 John Wiley & Sons, Inc.
Effect of esterase on methacrylates and methacrylate polymers in an enzyme simulator for biodurability and biocompatibility testing
Authors: Bean T. A. , Zhuang W. C. , Tong P. Y. , Eick J. D. , Yourtee D. M. 
Published: May 2005

AbstractCurrent in vitro biocompatibility methods do not evaluate the degradation of biomaterials after contact with enzymes that might be present in the oral or systemic environment. In this study, two methods of in vitro enzyme degradation and a method for the separation of the degradative products by high performance thinlayer chromatography (HPTLC) are reported. In the first method two dental adhesives, Scotchbond and Scotchbond II, and two dental composites, Helimolar and P‐50, were evaluated. These materials were incubated with four different enzymatic preparations for periods of up to 72 h. The enzymes were lipase, esterase, and liver enzyme extracts from both mouse and rat. Chloroform soluble products extracted from the aqueous phase were examined by HPTLC for decomposition products resulting from enzyme activity. The second method was similar, but analyzed the aqueous fraction directly without chloroform extraction. In this method five dental restorative materials, P‐50, P‐30, Scotochbond II, Silux, and Silux Plus, were incubated with a nonspecific porcine liver esterase. In addition to the polymerized biomaterials. Monomers containing methacrylic acid units were also hydrolyzed with esterase and analyzed by ion chromatography to establish the sensitivity of the enzyme simulator. Each biomaterial presented thin‐layer zones not present before enzymatic action. These experiments provide support that aqueous enzymatic action may facilitate the hydrolytic weakening of polymeric biomaterials. © 1994 John Wiley & Sons, Inc.