bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and bioevaluation of alkyl 2‐cyanoacryloyl glycolates as potential soft tissue adhesives
Authors: Jaffe H. , Wade C. W. R. , Hegyeli A. F. , Rice R. , Hodge J. 
Published: December 2004

AbstractA series of alkyl 2‐cyanoacryloyl glycolate tissue adhesives were synthesized and characterized by NMR. Physical properties and bond strengths are presented. Within the series, bond strength decreased with increasing molecular weight. Corresponding polymers were evaluated by in vitro and in vivo techniques for biocompatibility. In general, in vitro biocompatibility increased with molecular weight. Based on in vitro and in vivo results, the isobutyl and isoamyl derivatives gave polymers that were most biocompatible, however, the entire series was found to be less reactive than poly(methyl 2‐cyanoacrylate) and only the isopropyl derivative polymers more reactive than poly(isobutyl 2‐cyanoacrylate). Approximately one‐third of the isobutyl polymer biodegraded in vivo after 6 weeks.
Composites for use in posterior teeth: Mechanical properties tested under dry and wet conditions
Authors: Øysæd Harry , Ruyter Ivar Eystein 
Published: December 2004

AbstractThe purpose of this investigation was to determine some mechanical properties of eight different posterior composites, and how they are affected by water sorption. Creep characteristics in compression were expressed as compliance/log time functions. Stress‐strain relationship at a constant loading rate was determined both in compression and flexure, and presented as elastic modulus, ultimate strength, and ultimate strain. Water sorption increased creep values for all materials. Generally, the materials with the highest water sorption had the highest increase in creep. Water sorption decreased the elastic modulus and ultimate strength values. The creep values decreased and the elastic modulus increased with increasing quantity of inorganic fillers.
Zinc release from dental restorative materials in vitro
Authors: Meryon S. D. , Jakeman K. J. 
Published: December 2004

AbstractZinc release from a range of dental restorative materials was measured in the absence and presence of dentin over a 2‐week period. The presence of dentin was designed to simulate the residual dentin in vivo. There were considerable differences in both the levels and pattern of zinc release for the different materials. In several cases the concentrations exceeded the level which has been reported cytotoxic to cells in culture. With dentin, little zinc passed into solution, and high concentrations were measured in the dentin. This may explain the discrepancy between in vivo toxicity tests using zinc‐containing materials and previous in vitro tests which have not included dentin in the test system.
A simple method to heparinize biological materials
Authors: Noishiki Yasuharu , Miyata Teruo 
Published: December 2004

AbstractA new method was developed inducing antithrombogenicity to biologic materials. A basic protein, protamine, was used to increase heparin binding to collagenous materials. Protaminie sulfate solution was poured into a collagen‐rich material (porcine ureter). The protamine adsorbed to the collagen was then cross‐linked to the material by glutaraldehyde. The collagen‐protamine complex was then interacted with a heparin solution to ionically bind heparin to the material. The amount and the distribution of the bound heparin can be controlled by changing the protamine fixation to the material. A heparinized porcine ureter as a vascular substitute showed excellent antithrombogenicity in experimental animal studies. This method is expected to be used as a method for developing antithrombogenic artificial organs, and as a method for the development of antiadhesive membranes.
Polyacrylic acid–metal adhesive bond joint characterization by x‐ray photoelectron spectroscopy
Authors: Nasu Toshio 
Published: December 2004

AbstractThe adhesive force to human tooth and metallic restoration of dental cements which contain polyacrylic acid (PAA) is found to be stronger than that of previous cements. Chemical interaction at the interface between metals and carboxylate groups of PAA were studied by x‐ray photoelectron spectroscopic method combined with Ar+‐ion beam etching technique to examine the mechanism of adhesion. A 2.5 wt% aqueous solution of PAA was painted on the surface of metal plates which are usual elements of dental alloy. Ar+‐ion etching was used to scrape off in situ the PAA film coated on the metal plate gradually in the sample chamber of the ESCA equipment. After a few minutes of etching, ESCA spectra were observed. The profile of the spectra and binding energy of 4f5/2 and 4f7/2 levels of Au coated with PAA show little change by the Ar+‐ion etching, and remain in the same state as those of uncoated Au. Similar behaviours were obtained in case of Pt. There are three chemical states on Sn plate coated with PAA. The lowest binding energy peak is assigned to pure Sn. The middle one is assigned to SnO2. The highest one corresponds to Sn combined with carboxylate groups of PAA. The chemical reaction corresponding to the highest binding energy peak seems to contribute to the strong adhesive force of these cements to Sn. These aspects of spectra corresponded to McLean's results which showed that these cements had weak adhesion to Au and Pt, but strong adhesive force to tinned Au and Pt.
On the correlation between the failure of vascular grafts and their structural and material properties: A critical analysis
Authors: Pourdeyhimi B. , Wagner D. 
Published: December 2004

AbstractA statistical investigation of reported vascular graft failures over a period of 30 years is undertaken. The most important causes of graft failure are underlined, as well as the time to failure and relative frequency of each failure mechanism. This brings out the need for a critical review of the properties of basic textile structures used in today's vascular prosthetic grafts. The physiologic and structural factors which contribute to mechanical failure of arteries and artery/implant composite systems are analyzed. The importance of obtaining the complete set of time‐dependent elastic constants of the artery—which is viewed as an anisotropic material—is pointed out. Future research areas important for characterizing the mechanical behavior of artery/implant systems are suggested, with the aim of establishing rational standards for prosthesis evaluation.
Ex vivo interactions and surface property relationships of polyetherurethanes
Authors: Lelah Michael D. , Grasel Timothy G. , Pierce Jeffrey A. , Cooper Stuart L. 
Published: December 2004

AbstractDespite the use of polyurethanes in a number of blood‐contacting applications, little is known about the contributing effects of the various polyurethane components in thrombogenesis. In order to investigate blood‐polyurethane interactions, a number of different polyurethanes were examined in an acute canine ex vivo series shunt experiment. Multiprobe surface characterization techniques, including contact angle measurements, ESCA, ATR‐IR, and SEM were used to obtain surface property information on the materials studied. The polyurethanes examined included several with different soft segment types, a series of materials with different hard segment diisocyanates and chain extenders, a series consisting of the same polymer cast from different solvents, a zwitterionomer, and a hard segment analog. Two commercial urethanes were also examined, and the effect of methanol extraction on these materials was studied.The blood‐contact and surface characterization results indicated that both the surface concentration and type of hard segment were of importance in determining blood response. The relative concentration of hard segment on the polymer surface was found to affect the observed blood‐material interaction, although the extent of this effect was found to depend on the hard and soft segment components of the copolymer system. Both the surface properties and thrombogenicity of a particular polyurethane were changed by casting from different solvents, indicating the need to optimize and control fabrication conditions. Methanol extraction was found to improve the thromboresistance of the commercial polyurethanes.
Quantitative surface analysis of cardiothane 51 by FT‐IR‐ATR spectroscopy
Authors: Iwamoto Reikichi , Ohta Koji , Matsuda Takehisa , Imachi Kou 
Published: December 2004

AbstractSurface analysis has been carried out for Cardiothane 51 samples as commercially available balloon pumps and cast films prepared from the solution. Silicone contents on surfaces have been quantitatively determined by FT‐IR‐ATR spectroscopy coupled with a subtraction technique. The contents on the air‐facing surface vary from 0.7 to 5.3% among six balloon pumps examined; three of them contain less silicone on the air‐facing surface than on the substrate‐facing surface, whereas just the opposite is true for one, and the other two have nearly and quite an equal content of it between the two surfaces. Silicone contents on surfaces of cast films vary also from a sample to another even when sample films were prepared from the same Cardiothane solution, indicating difficulty in quality control of Cardiothane surfaces. An appreciable fraction of silicone was found not to be covalently bonded to polyurethane in Cardiothane 51 for the cast film samples.
Mechanical properties of polymeric membranes obtained by radiation cast‐polymerization of hydroxyalkyl and hydroxypolyethyleneglycol methacrylate monomers
Authors: Kumakura M. 
Published: December 2004

AbstractPolymeric membranes have been prepared by radiation cast‐polymerization of hydroxyalkyl and hydroxypolyethyleneglycol methacrylate monomers, and the mechanical properties of the membranes before and after swelling have been studied as a function of the molecular structure of the monomers. The degree of hydration of the polymers from hydroxypolyethyleneglycol methacrylate monomers increased with increasing the number of ethyleneglycol units in the monomers, and that from hydroxyalkyl methacrylate monomers decreased with an increase in the number of methylene units. The mechanical properties such as tensile strength, tear strength, Young's modulus, and elongation at break varied with the length of the methylene and ethyleneglycol units in the monomers. It was found that flexible polymeric membranes having various properties for medical applications could be obtained by radiation cast‐polymerization of hydroxyalkyl and hydroxypolyethyleneglycol methacrylate monomers.
Use of concentrated fibrinogen in experimental splenic trauma
Authors: Kram Harry B. , Hino Stanley T. , Harley Daniel P. , Fleming Arthur W. , Shoemaker William C. 
Published: December 2004

AbstractThis study evaluated Fibrin Sealant (FS), a two‐component biologic adhesive that is effective in establishing hemostasis, in 27 experimentally produced splenic injuries in five adult mongrel dogs. Ten small superficial lacerations (2.0 cm in length), six large superficial lacerations (3.0–6.0 cm in length), three small wedge resections, and eight stab wounds extending into the splenic hilum were effectively repaired with FS without suture splenorrhaphy or temporary splenic hilar occlusion. Complete hemostasis was achieved in all animals prior to skin closure. Dogs were reexplored postoperatively at intervals varying from 4 h to 6 weeks. When animals were killed, there was no gross evidence of splenic disruption or recurrent bleeding; the spleens all had developed well‐healed capsules. Histologic examination demonstrated a regenerated fibrous capsule extending over the injuries without significant inflammatory response. We conclude that FS (1) provides adequate hemostatic control of superficial and deep splenic injuries; (2) has good systemic and local compatibility; (3) can be applied to bleeding parenchymal wounds; organ ischemia is generally not required; (4) avoids the use of parenchymal sutures, which may be traumatic; and (5) may promote splenic wound healing. Thus, use of FS is an effective technique for splenic preservation after trauma.
The effect of annealing treatments on the tensile properties and hydrolytic degradative properties of polyglycolic acid sutures
Authors: Browning Abigail , Chu C. C. 
Published: December 2004

AbstractThe purpose of this research was to examine the effect of annealing treatments on the mechanical properties of polyglycolic acid sutures, and their subsequent influence on PGA degradation properties. An attempt was made to develop a better understanding of the degradation mechanism of synthetic absorbable sutures, including the relationship of their structure, morphology, and mechanical properties. PGA sutures were annealed under selected axial strain (freely hung, 0%, 1%, 10%), at four temperatures (150°C, 170°C, 180°C, 190°C), and two times (5 and 20 min). The annealed PGA specimens were then subjected to hydrolysis in phosphate‐buffer solutions (pH = 7.4) for up to 28 days at 37°C. Tensile properties were used to evaluate the effect of annealing treatments. The data were subjected to statistical analysis using the SAS system. All of the one‐, and many of the two‐ and three‐factor interactions were found to be statistically significant. Annealing treatments did alter the mechanical properties of PGA sutures, as well as their degradation properties. Except for the increase in tenacity of samples with increasing percent extension, all other respects of the annealing treatments resulted in lower tenacity and breaking elongation when compared with the control samples. Sutures that have been exposed to any level of axial tension during annealing, however, exhibited a lower rate of hydrolytic degradation than the freely hung suture samples. The reduction of the characteristics of fiber structure due to the tendency of the tie‐chain molecules to acquire the less constrained conformations and thus to bring the crystal blocks they connect back to the original arrangement before drawing is believed to be responsible for the freely hung specimens to behave quite differently from the clamped and stressed PGA samples.
Quantitative characterization of cells at the interface of long‐term implants of selected polymers
Authors: Behling Cynthia A. , Spector Myron 
Published: December 2004

AbstractComprehensive understanding of the relationship between biologic response and biomaterial characteristic requires quantitative evaluation of the cells at the interface of the material and descriptions of untrastructural features of these cells. The purpose of this study was to qualitatively and quantitatively characterize the long term in vivo tissue and cellular response to two polymeric materials presently employed in the fabrication of surgical implants. Ultrahigh molecular weight polyethylene (PE) and polysulfone (PSF) particles were implanted subcutaneously into rats for 100–118 weeks. Specimens were embedded in paraffin and ERL embedding medium in preparation for light and transmission electron microscopy. Percentage of the particle surface covered by various cell types was determined using a computer interactive image analysis system. PE and PSF particles were sequestered within a subcutaneous fibrous capsule. Cell types present included macrophages, fibroblasts and giant cells characteristic of a foreign body granuloma. Statistical comparison of the percent particle surface covered by each cell type revealed no significant difference between PSF and PE. However, surface texture appeared to influence the tissue response. TEM confirmed the identity of the cells at the interface and consistently revealed a layer of amorphous extracellular substance including cell debris on the material surface. Results evidence the tissue compatibility of PE and PSF and indicate no significant difference in the tissue response to these polymers.
Ligament and tendon substitution with composite carbon fiber strands
Authors: Mendes David G. , Iusim Mauricio , Angel David , Rotem Assa , Mordehovich Dan , Roffman Moshe , Lieberson Samuel , Boss Jochanan 
Published: December 2004

AbstractCarbon fiber strands were used experimentally to substitute for tendons in dogs and clinically to reconstruct tendons and ligaments in human. The investigation was carried out to determine the histologic appearance of the new composite structure and its tensile strength in comparison to the natural structure. The histologic picture disclosed a remarkable structure evolved by continuous irritation of the carbon fibers and consisting of two interrelated components: synthetic carbon fibers and biologic collagenous tissue. This carbon fiber composite structure was composed of long cylindrical units containing concentric layers of collagenous fibers and cells enveloping the core of each carbon fiber. After one year of physiologic use in dogs, the average ultimate tensile strength of the composite structure which replaced the quadriceps and triceps was 372 N, or 88% the strength of the natural tendons. One year after implantation the histologic picture of the composite structure in human showed a relatively dense collagenous architecture. However, a significant proportion of the structure was taken up by histiofibroblasts produced by the irritation of the carbon fibers. Thus, the density of the collagen in the composite structure remained relatively deficient in comparison to the nature tendon, and the structural tensile strength continued to depend entirely on the integrity of the carbon fibers.
Pulmonary reaction to intravenously injected polymer beads
Authors: Schoen Frederick J. , Kintanar Esperanza B. , Osol Rosalie G. , Lee Ellen 
Published: December 2004

AbstractThe purpose of this study was to characterize the foreign body reaction in the mouse lung following embolization of intravenously injected divinylbenzene copolymer beads. In contrast to usual surgical implantation, this model dissociates the local foreign body reaction to the beads (in the lung) from inflammation and repair of tissue injury associated with implantation (peripheral site of injection). Quantitative determinations of pulmonary granuloma area using light microscopic morphometric measurements on tissue sections confirmed that the intensity of pulmonary inflammatory reaction increased rapidly to a maximum at 48 h following injection, with a volume exceeding 10 times that of the bead; at this time, the cellular exudate was 90% polymorphonuclear leukocytes. Thereafter, the inflammatory reaction decreased in intensity, and individual lesions became progressively richer in mononuclear cells (60% at 4 days and greater thereafter). Determination of intra‐ and interobserver variability indicated that maximal data precision was attained by measurement of the cross‐sectional areas of as few as 10 granulomas in each of five animals for each set of specific experimental conditions. Collagen was undetectable in granulomas at 7 weeks and 6 months, suggesting that the usual fibrous capsule forming in response to surgically implanted biomaterials is largely caused by repair of surgical trauma. The volume of inflammatory exudate at 48 h was reduced 68–86% by the nonsteroidal antiinflammatory agents indomethacin, aspirin, and ibuprofen and the antiinflammatory steroid methylprednisolone. Thus, the pulmonary bead granuloma model is a quantitative, reliable, and economical approach to investigating some aspects of biomaterial/time interactions in the absence of superimposed surgical trauma.
Red blood cells deposit membrane components on contacting surfaces
Authors: Borenstein N. , Brash J. L. 
Published: December 2004

AbstractAn investigation of red blood cell interactions with “foreign” surfaces is reported. Experiments consisted of flowing suspensions of washed human red cells through a packed column of either glass or siliconized glass beads. Conditions were chosen so that hemolysis was minimized. The column was washed to remove suspended red blood cells and then eluted. Samples of beads were examined by SEM after washing and before elution. The eluate was examined by UV/visible spectroscopy and SDS‐PAGE; for both types of packing it was found to contain cell membrane components. It is therefore concluded that membrane material is deposited on the bead surface as the cells flow through the column. The SDS‐PAGE data show that membrane skeleton proteins are essentially missing from the eluate, while SEM examination indicates the presence of filamentous deposits on the bead surfaces. These data suggest that cell‐surface interaction may occur through a tether‐type mechanism involving extrusion of part of the membrane including the integral membrane proteins.
Omiderm, a new synthetic wound covering: Physical properties and drug permeability studies
Authors: Behar D. , Juszynski M. , Ben Hur N. , Golan J. , Eldad A. , Tuchman Y. , Sterenberg N. , Rudensky B. 
Published: December 2004

AbstractOmiderm (Omikron Scientific Ltd., Rehovot, Israel), a new synthetic wound covering based on hydrophilized polyurethane, was found to be highly permeable to water. Values in the region of 5000 g/m2 24 h were found for the water permeability of Omiderm in comparison to 1400 and 500 g/m2 24 h for Biobrane (Hall, Woodroof Inc., Santa Ana, CA) and Op site (Smith and Nephew Ltd.), respectively. Permeabilities of antibacterial agents through Omiderm were found to be two to three orders of magnitude greater than those through Biobrane. The in vitro effectiveness of various antibacterial agents in lowering bacterial growth of different bacterial strains when applied to seeded agar plates through Omiderm membrane was investigated. NBH ointment (1% Neomycin, 1% Bacitracin, and 0.5% Hydrocortisone) was found to be the most effective material in inhibiting bacterial growth, except for Pseudomonas aeruginosa where silver sulfadiazine was superior. In in vivo experiments bacterial counts of infected wounds covered with Omiderm and topically treated with NBH were lowered to less than 103 organism/g tissue after one day of treatment.
Comparison of in vitro bacterial bioluminescence and tissue culture bioassays and in vivo tests for evaluating acute toxicity of biomaterials
Authors: Burton S. A. , Petersen R. V. , Dickman S. N. , Nelson J. R. 
Published: December 2004

AbstractThe sensitivity of a bacterial bioluminescent acute toxicity test was compared to the sensitivity of the USP mouse safety, rabbit intramuscular implantation, rabbit intracutaneous, mouse systemic injection, and the MEM elution tissue culture tests. A variety of industrial plastics were used to evaluate the comparative sensitivities. Additional tests were conducted on lowdensity polyethylene containing a range of dibutyltin dichloride or trans‐cinnamic acid concentrations. The bacterial bioluminescent test was more sensitive than any of the in vivo acute toxicity tests. The luminescent bacteria test was generally more sensitive than the tissue culture acute toxicity assay. The bacterial bioluminescent test offers a sensitive, rapid, uncomplicated, and inexpensive means for preliminary compatibility evaluation of biomaterials.
Fracture analysis of retrieved orthopedic wires
Authors: Baswell Imogene L. , Sander Tom , Allen Ben , Bechtol Charles O. 
Published: December 2004

AbstractTen retrieved samples of 316L stainless steel wires, implanted for times from 11 months to 11 years, were examined fractographically and metallurgically to evaluate the effects of a physiological environment on their fracture. Seven samples were from L‐rod instrumentation, and three samples were from trochanter reattachment. Of 16 breaks in the 10 samples, 94% were caused primarily by cyclic loading (fatigue), and 6% were caused by tensile forces. Two factors were found to influence the effective life of an implanted wire. First, the surface condition (deformation) appeared to be most important, and second, corrosion pits present on most wire surfaces could possibly be an influence in initiating a crack. Biomechanical forces on wires enveloping L‐rods tended to promote metal deformation and faceting, which decreased time to fracture. This decrease in wire life was evident from a substantial hardness increase in faceted areas.