bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phase studies of a urethane model compound and polyether macroglycols by infrared spectroscopy and the relationship between eutectic composition of soft segment and blood compatibility
Authors: Isama Kazuo , Kojima Shigeo , Nakamura Akitada 
Published: May 2005

AbstractThe binary mixtures of a urethane model compound, diethyl 4,4′‐methylenebis(N‐phenylcarbamate) (MDU), and various polyether macroglycols have been investigated mainly by infrared (IR) spectroscopy. The mixtures of macroglycol and MDU showed two CO bands (free CO at higher wave number, hydrogen bonded CO at lower wave number), and the intensity of free CO increased while that of hydrogen bonded CO decreased linearly with increasing molar ratio of macroglycol/MDU. The slope of the increase or decrease suddenly changed at the specific molar ratio around the eutectic composition. The eutectic molar composition for PTMO1000/MDU was determined as 1.15 or 1.1 by differential scanning calorimetry (DSC) or infrared (IR) studies while that for PTMO3000/MDU as 0.345 or 0.55 by DSC or IR, respectively. The eutectic compositions for other sets were determined by IR studies as follows: PEO1000/MDU, 0.4; PEO3000/MDU, 0.16; PPO1000/MDU, 1.4; PPO3000/MDU, 0.45. The number of ethylene oxide, tetramethylene oxide, and propylene oxide units to form a eutectic with MDU calculated from these values were 15–20, 10–11, and 23–24, respectively. The similar DSC or IR changes were observed in the various kinds of polyurethanes such as MDI/BD, MDI/MDI/PTMO/BD, and MDI/PTMO polymers. The relationship between the eutectic compositions of soft segments (MDI/macroglycol) and the ideal Mn of the macroglycols in blood compatibility of segmented polyurethanes are discussed. © 1993 John Wiley & Sons, Inc.
Interactions of complement fraction C1q, fibronectin, and immunoglobulin G with polyacrylic microparticles used as solid‐phase in immunoassay
Authors: Cliquet F. , Cuillière M. L. , Montagne P. , Duheille J. 
Published: May 2005

AbstractA microparticle‐enhanced nephelometric immunoassay was recently described, where polyacrylic, hydrophilic, and polyfunctional microparticles are used as the solid phase. It is a one‐step immunoassay based on the nephelometric quantification of microparticle agglutination. In such assays, the measurement of analytes at low concentration may be impaired by the need of using undiluted biological samples. This leads to work with high concentrations of several proteins liable to interfere with the agglutination process. In this paper, we report on a study performed with human serum and purified proteins, which were assayed by classical analytical methods. This work identified three major components of human serum specifically involved in yielding polyacrylic microparticle instability: complement fraction C1q, fibronectin, and immunoglobulins G. In this order of importance, they all showed a marked ability to be adsorbed on the microparticle's surface. Pretreatment of human serum with microparticles decreased the concentrations in C1q (82%), fibronectin (16%), and immunoglobulin G (4%) very unequally. However, it allowed the elimination of microparticle instability, consequently providing the possible use of such polyacrylic microparticles in a one‐step nephelometric immunoassay of analytes at low concentration in biological samples, without washes or phase separation. © 1993 John Wiley & Sons, Inc.
Salicylic acid prevents the adherence of bacteria and yeast to silastic catheters
Authors: Farber Bruce F. , Wolff Arlene G. 
Published: May 2005

AbstractDuring the pathogenesis of catheter‐related urinary tract infection, bacteria attach to the catheter and migrate along a biofilm into the bladder. We studied the effect of coating silastic catheters with salicylic acid on bacterial and yeast adherence. An agar roll technique, bioluminescent assay, and radiolabeling study all produced consistent results. There was a dose related inhibition of adherence with Pseudomonas aeruginosa, Enterobacter aerogenes, Klebsiella pneumoniae, Candida albicans, and Enterococcus faecalis. Inhibition of over 90% was noted with Enterobacter and Pseudomonas. Similar results were obtained in broth and synthetic urine. A dose related reduction in adherence was seen with all gram‐negative rods and yeast as measured by a radiolabeling assay. TDMAC was used to bind the salicylic acid to the catheters with > 95% inhibition of the gram‐negative rods. These studies suggest the potential role of coating catheters with salicylic acid to reduce bacterial adherence and urinary tract infection. © 1993 John Wiley & Sons, Inc.
Histomorphometric assessment of the mechanisms for rapid ingrowth of bone to HA/TCP coated implants
Authors: Burr David B. , Mori Satoshi , Boyd Robert D. , Sun T. C. , Blaha J. David , Lane Leon , Parr Jack 
Published: May 2005

AbstractThe purpose of this work is to use dynamic histomorphometry to evaluate the basic biological mechanisms by which hydroxyapatite/tricalcium phosphate (HA/TCP) implant coatings accelerate bone formation rates. Twenty‐five rabbits had an HA/TCP coated cylindrical titanium fiber metal mesh implant surgically placed in the subchondral bone of the proximal tibia and a noncoated implant placed in the contralateral tibia. Twenty‐two of these animals had HA/TCP coated cylindrical solid titanium implants placed in the distal femur and an uncoated implant placed in te contraleteral femur. The animals were double labeled with vital stains, and sacrificed at 3, 6, 16, or 26 weeks after surgery. Histomorphometric analyses were done of the bone implant interfaces. Both static and dynamic histomorphometric parameters indicate that HA/TCP coatings stimulate faster bone ingrowth to coated fiber metal implants through the early production of woven bone and by subsequent rapid lamellar bone formation rates. Coated fiber metal implants demonstrated significantly more bone ingrowth than noncoated implants through 16 weeks postimplatatin, but not by 26 weeks, In solid implants, the differences between coated and noncoated implants are less pronouned and not statistically significant, although there is a trend toward increased bone appostion to the surface of the implants over the first 16 weeks following implantation. The clinical significance of these results is that coated implants may allow earlier return to normal weightbearing. © 1993 John Wiley & Sons, Inc.
Collagen types I and III at the implant/tissue interface
Authors: von Recum A. F. , Opitz H. , Wu E. 
Published: May 2005

AbstractCollagen composition in tissue capsules around implants has been reported to deffer histologically from collagen in subcutaneous connective tissue. In the present study, an immune histochemical analysis of collagen types I and III was undertaken in tissue capsules of various implant materials. The materials in cluded polyvinyl chloride/polyacrylonitrile copolymer, poly(ethylene terephthalate), polysiloxane, titanium, and hydroxyapatite, which had been implanted into the dorsal subcutaneous space of rabbits for various time periods from 28 and to 90 days. The results indicate that collagen type III stained in all capsules independent of the evaluated materials, implantation periods, and material surface roughness. Collagen type I stained only in titanium implant capsules and dominated there over collagen type III. The staining sensitivity was highly specific and reproducible. The presence of collagen type III can be expected because it is the collagen of connective tissue healing. Collagen type I appears to be a response to chemical or electrochemical titanium surface properties but not to surface roughness. The quantitative relationship between the two collagen types may indicate capsule tissue stability and therefore serve as another biocompatibility measure. © 1993 John Wiley & Sons, Inc.
Detection of remnant proteolytic activities in unimplanted glutaraldehyde‐treated bovine pericardium and explanted cardiac bioprostheses
Authors: Simionescu Dan , Simionescu Agneta , Deac Radu 
Published: May 2005

AbstractThe presence and activity of proteolytic enzymes has been investigated in vitro on slouble and insoluble preparations obtained from both unimplanted and implanted glutaraldehyde‐treated bovine parietal pericardium. Using detection by colorimetric techniques, soluble preparations were shown to hydrolyze enzyme substrates that are characteristic for trypsinlike proteases, cathepsin‐like proteases, and collagenase. As detected by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis in gradient gels and gel filtration on Sepharose CL‐6B, insoluble (pellet) preparations degraded denatured type I collagen in a time‐dependent pattern, producing low‐molecular‐weight fragments. These activities were partially inhibited by phenylmethylsulfonyl fluoride, N‐ethyl maleimide, soybean trypsin inhibitor, parachloromercurybenzoic acid, or ethylenediaminetetraacetic acid, suggesting the presence of a heterogeneous enzymatic mixture. Insoluble preparations incubated with pure pericardial dermatan sulfate proteoglycan detached the glycosaminoglycan chains from their core protein carrier, producing a digestion pattern similar to Cathepsin C. These findings demonstrate the presence of active proteases in glutaraldehydefixed bovine pericardium per se and in explanted pericardial bioprosthetic cardiac valves, an additional factor that might contribute to intrinsic extracelluar matrix degeneration in pericardial bioprosthetic devices. © 1993 John Wiley & Sons, Inc.
New ideas in biomaterials science—a path to engineered biomaterials
Authors: Ratner Buddy D. 
Published: May 2005

AbstractOur existing biomaterials, although demonstrating generally satisfactory clinical performance, were developed based upon a trial‐and‐error optimization approach rather than being engineered to produce the desired interfacial reaction. Most biomaterials exhibit a nonspecific biological reaction, with sluggish kinetics and a broad spectrum of active processes simultaneously occurring. This article describes materials science, nanotechnology, and molecular biology techniques that may permit the synthesis of precisely engineered surfaces. Such surfaces might demonstrate rapid, precise reactions with proteins and cells. This opens the question, “what type of specific surface bioreactions do we want?” New thoughts on biocompatibility are presented that may be helpful in the design of specific surfaces yielding precise, defined biological responses. © 1993 John Wiley & Sons, Inc.
Behavior of primary bone cells on characterized polystyrene surfaces
Authors: Callen B. W. , Sodhi R. N. S. , Shelton R. M. , Davies J. E. 
Published: May 2005

AbstractPrimary bone cells, isolated from the periosteally stripped calvariae of neonate rats, were cultured on 60Co γ‐irradiation‐sterilized bacteriologic‐grade polystyrene that had been either surface treated with concentrated sulfuric acid or received further γ‐irradiation treatments facilitated cell colonization of the polystyrene compared to those surfaces not treated in the laboratory. x‐Ray photoelectron spectroscopy (XPS) showed that the two treatments introduced different chemical groups onto the polymer surface and that cell adhesion was related to γ‐irradiation in a dose‐dependent manner. These results show that simple biologic assays, such as cell colonization, are not able to distinguish between differences in surface chemistry demonstrated by such a routinely employed surface analysis technique. Thus, there is a need to develop more sensitive biologic assays that provide functional information of a precision that can be correlated with subtle changes in substratum surface chemistry. Further, we argue that because cells isolated by tissue digestion using proteolytic enzymes respond more readily to changes in the surface chemistry of the substratum they colonize, compared to explanted cells; biologic assays designed for biomaterials testing must take into account changes effected in cell adhesion behavior by isolation procedures. © 1993 John Wiley & Sons, Inc.
Delivery of growth factor to wounds using a genetically engineered biological bandage
Authors: Leyen Sheila Andreatta‐Van , Smith Daniel J. , Bulgrin Jeffrey P. , Schafer Irwin A. , Eckert Richard L. 
Published: May 2005

AbstractIncreasing the rate of wound healing of acute wounds and promoting the closure of chronic ulcers is an important goal in wound therapy. Growth factors have been shown to facilitate this process; however, the systems described for growth factor delivery are not ideal. In the present report we demonstrate the feasibility of a new method of delivering growth factors to the wound site using a genetically engineered biological bandage. The bandage consysts of keratinocytes (SCC‐13 cells) that are engineered by gene transfer to produce high levels of bovine growth hormone (bGH). bGH was selected for these studies because it can be easily distinguished from rat and human growth hormone in wound fluids and culture medium. The bGH‐producing cells are contained and maintained in serum‐free medium inside an envelope composed of a low protein binding, 0.2 μm pore size, polysulfone membrane. The genetically engineered cells cannot escape from the bandage, but the bGH is freely released into the surrounding culture medium. When placed onto a full‐thickness, surgically generated wound on rats, the cells within the bandage continue to produce and release bGH into the wound for at least 3 days. This system is a safe and reliable way of providing real‐time delivery of any desired biomolecule into the wound site. © 1993 John Wiley & Sons, Inc.
Prevention of thrombus formation on biomaterials exposed to blood using different antiplatelet drugs: Experimental study in dogs
Authors: Escudero M. C. , Alvarez L. , de Haro J. , Millán I. , Jorge E. , Castillo‐Olivares J. L. 
Published: May 2005

AbstractAn ex vivo shunt, established in dogs between both femoral arteries and right atrium, has been used to quantify the platelet deposition on six prosthetic materials used in the construction of cardiovascular prostheses: highly porous knitted Dacron (intervascular HP 800, 1400 mL/cm2/min/120 mm Hg), low‐porosity woven Dacron (intervascular LP 200, 200 mL/cm2/min/120 mm Hg), double velour knitted Dacron, Avcothane 51 elastomere, and the mesothelial and epipericardial surfaces of bovine pericardium. In the search for a method to prevent platelet thrombi formation on these materials, we studied four groups of dogs: group 1 (control), group 2 (5 mg/kg body weight (BW)/day acetylsalicylic acid), group 3 (20 mg/kg BW/day acetylsalicylic acid), and group 4 (5 mg/kg BW/day acetylsalicylic acid plus 5 mg/kg BW/day dipyridamole). Platelets were labeled with 111In‐oxine. The least thrombogenic material was Avcothane 51 elastomere. The only effective treatment for reduction of platelet deposition on the six materials was 5 mg/kg BW/day of acetylsalicylic acid. The dose used in group 3 only decreased the deposition of platelets on three of the six materials studied. The treatment employed in group 4 did not significantly reduce the deposition of platelets on any of the materials when compared with the control group. © 1994 John Wiley & Sons, Inc.
The role of hydrated silica, titania, and alumina in inducing apatite on implants
Authors: Li Panjian , Ohtsuki Chikara , Kokubo Tadashi , Nakanishi Kazuki , Soga Naohiro , de Groot Klaas 
Published: May 2005

AbstractPure soluble silica prepared by a sol‐gel method induced bone‐like hydroxyapatite formation onto its surface when the silica was immersed in a simulated body fluid (SBF), whereas silica glass and quartz did not. This finding directly supports the hypothesis that hydrated silica plays an important role in biologically active hydroxyapatite formation on the surfaces of bioactive glasses and glass‐ceramics, which leads to bone‐bonding. Gel‐derived titania is also a hydroxyapatite inducer because of its abundant TiOH groups. These results provide further insight into the unique osseointegration of titanium and its alloys. It is suspected that gel‐derived titania develops an apatite layer by taking calcium and phosphate from the body fluid, thus producing bonebonding. Although sufficient AlOH groups may remain in the alumina gel, they do not serve to initiate apatite generation when immersed in SBF. This phenomenon explains the fact that an intermediate fibrous tissue is usually found to separate the alumina implant from bone. One may infer that both abundant OH groups and negatively charged surfaces of gel‐derived silica and titania are important for hydroxyapatite induction. Material which possesses and / or develops both a negatively charged surface and abundant OH groups in a physiologically‐related fluid is most likely to be an efficient apatite inducer. Such materials are suitable candidates to serve as bone‐bonding biomaterials. © 1994 John Wiley & Sons, Inc.
Theoretical analysis of in vivo macrophage adhesion and foreign body gaint cell formation on polydimethylsiloxane, low density polyethylene, and polyetherurethanes
Authors: Kao Weiyuan John , Zhao Qing H. , Hiltner Anne , Anderson James M. 
Published: May 2005

AbstractQuantitative description of foreign body giant cell (FBGC) formation on implanted polymer surfaces as a function of time can conceivably correlate cell adhesion with polymer properties and possibly predict the behavior of the polymer in vivo. In the present study, the formation of FBGCs on various biomedical polymers was quantified by two parameters: the density of adherent macrophages present initially that participate in FBGC formation (d0) and the rate constant for cell fusion (k); both kinetic parameters were used to calculate the time‐dependent FBGC density (dfc).The materials used were: three Pellethane poly(etherurethanes) (PEUs) varying in weight percent of hard segment, one poly(etherurethane urea) (PEUU), and NHLBI‐DTB primary reference materials: low density polyethylene (LDPE), silica‐free polydimethylsiloxane (PDMS). The results indicated that up to 5 weeks of implantation, FBGCs were formed from the fusion of one population of adherent macrophages present by 3 days post‐implantation. Furthermore, only a small fraction (<8%) of this initial adherent macrophage population participated in FBGC formation. Based on the results of previous studies and the current study, it was concluded that increase in PEU hard segment weight percent, surface hardness and hydrophobicity increased total protein adsorption and effectively increased d0 and dfc. No further correlations between the material properties of all polymers and the cell kinetics can be made at this time. However, this study demonstrated that macrophage adhesion and FBGC formation can be quantified with the cell fusion model, and are modulated by various polymer properties. © 1994 John Wiley & Sons, Inc.
Histological changes of implanted collagen material during bone induction
Authors: Horisaka Yasuyuki , Okamoto Yasuo , Matsumoto Naoyuki , Yoshimura Yoshiyuki , Hirano Atsuko , Nishida Mikio , Kawada Jun , Yamashita Kikuji , Takagi Tomomichi 
Published: May 2005

AbstractStudies were made on the fate of implanted material during bone induction. Mixtures of 1 mg of crude bone morphogenetic protein (BMP), or bovine serum albumin as a control, and 1.5 mg of bovine collagen, were pressed into discs and implanted under the fascia of the rectus abdominus muscle of rats. The tissues with implants were fixed 7, 10, and 14 days later and examined histologically. On day 7 after implantation, the implant was surrounded and invaded by alkaline phosphatasepositive cells. New bone and cartilage were seen at the periphery of the implant. In the regions of calcified cartilage and bone, these osteogenic matrices were intermixed with the implant. The mineral deposits were seen by electron microscopy not only on the osteogenic matrices but also on the implanted collagen. On day 14, the bone had spread to the center of the implant. No osteogenesis or chondrogenesis was seen in control implants. It was concluded that the calcification occurred on the implanted collagen during bone induction, and that it was related to successive bone formation and remodeling. © 1994 John Wiley & Sons, Inc.
Comparison of 316LVM and MP35N alloys as charge injection electrodes
Authors: Cogan Stuart F. , Jones George S. , Hills Doris V. , Walter James S. , Riedy Lisa W. 
Published: May 2005

AbstractAn In vitro comparison of the corrosion response of 316LVM stainless steel and MP35N (a CoNiCrMo alloy) electrodes under conditions appropriate to applications in functional electrical stimulation (FES) was made. Electrodes of both alloys were subjected to a cathodic 40 μC/cm2 charge injection protocol and the potential transient response was recorded over a 96 h period. The transient responses were compared with potentiodynamic polarization data used to establish the quasiequilibrium response of the alloys in the carbonate and phosphate‐buffered saline electrolyte used in the study. The MP35N electrodes exhibited extensive pitting corrosion during charge injection, whereas little corrosion was observed on 316LVM electrodes. An explanation for the susceptibility of MP35N to corrosion during charge injection is found in the potentiodynamic polarization data, which reveal a breakdown potential (critical pitting potential) of 0.45 V (SCE) for MP35N compared with 1.05 V (SCE) for 316LVM. Factors that may influence corrosion response during charge injection from alloys exhibiting active–passive behavior are discussed. © 1994 John Wiley & Sons, Inc.
Adsorption and activation of zymogens at solid–liquid interfaces. I. Chymotrypsinogen on alkylamino modified silica derivates
Authors: Yen Hung‐Ren Homer , Oscarsson Sven , Ulbrich Karel , Kopeček Jindřich 
Published: May 2005

AbstractSilica beads were modified with alkylamino groups of different lengths (C2, C4, C6, C8, and C10) and hydrophobicity. The relationship between surface structure and adsorption of chymotrypsinogen followed by its activation with trypsin at the solid‐liquid interface was studied. From the adsorption isotherms, it follows that underivatized silica adsorbed chymotrypsinogen (CTG) well. The adsorption of CTG on alkylamino modified silicas appeared to correlate with the hydrophobicity of the latter. The longer the alkyl chains were, the higher was the amount of adsorbed CTG. The activation of adsorbed CTG with trypsin at the solid—liquid interface was a slower process when compared with the activation conducted in solution. Parallel experiments were performed with chymotrypsin (CT). The adsorption behavior was similar to that of CTG. The activity of adsorbed CT was inversely proportional to the hydrophobicity of the beads. These results correlated well with the desorption of CT after repeated washings. Repeated addition of substrate (Gly‐Gly‐Phe‐NAp) to the CT covered beads resulted in the CT desorption. The higher the hydrophobicity of the beads was, the lower was the desorption of CT. © 1994 John Wiley & Sons, Inc.