bluuebunny/crossref_metadata_2025_split huggingface dataset:
The peroxidase antiperoxidase staining of factor VIII‐related antigen on cultured endothelial cells
Authors: Baughman Sally , Herring Malcolm , Glover John , Dilley Russell 
Published: December 2004

AbstractTo prevent the premature occlusion of vascular prostheses, endothelium is being cultured experimentally onto synthetic flow surfaces. A rapid method of identifying cultured endothelium on the prosthesis is valuable for determining the degree of fibroblast and smooth muscle cell contamination and to screen for endothelial cell transformation. Fluorescent Factor VIII related antigen (FVIII‐RA) staining has been used to identify cultured endothelium, but results in excessive staining of the underlying prosthesis, loss of morphologic detail, and deterioration of the FVIII‐RA antibody reaction with time. We have applied the peroxidase antiperoxidase (PAP) method of antigen staining to permit staining of FVIII‐RA and thereby to permit a sensitive and specific identification of human or canine endothelium with a concurrent analysis of morphologic detail.
The formation of stain on acrylic surfaces by the interaction of cationic antiseptic mouthwashes and tea
Authors: Addy M. , Moran J. 
Published: December 2004

AbstractClinical and in vitro studies have implicated dietary components as major aetiological factors in staining of teeth and acrylic materials associated with chlorhexidine use, a local side effect not unique to this antiseptic. These experiments studied the precipitation and surface staining reactions of the cationic antiseptics alexidine, cetyl pyridinium chloride (CPC), chlorhexidine, and hexetidine, with the beverage tea. All of the antiseptics precipitated a standard tea solution and for alexidine and chlorhexidine acetate and gluconate, this was at concentrations >100 μmol/L, for hexetidine >200 μmol/L, and for CPC >400 μmol/L. With the exception of CPC precipitation was reduced with decreasing pH and for chlorhexidine was inhibited below pH 3. The addition of polymethylmethacrylate (PMMA) to the antiseptic solutions increased the precipitation concentrations by an amount calculated to be adsorbed by polymer. Acrylic blocks treated with equimolar solutions of the antiseptics became progressively and significantly more stained by tea than control specimens over a 5‐day period. Alexidine induced significantly greater staining and hexetidine significantly less than the other antiseptics. Staining was pH dependent and significantly reduced as the pH decreased. Both stain and precipitates were insoluble in strong acids and alkalis. It is concluded that staining observed clinically may represent a precipitation reaction with the complexing of antiseptics with dietary chromogenic material.
Modification of polyetherurethane for biomedical application by radiation induced grafting. II. Water sorption, surface properties, and protein adsorption of grafted films
Authors: Jansen B. , Ellinghorst G. 
Published: December 2004

AbstractA series of polyetherurethane films grafted by means of γ radiation with hydrophilic or reactive monomers (2‐hydroxyethyl methacrylate, 2,3‐epoxypropyl methacrylate, 2,3‐dihydroxypropyl methacrylate, and acrylamide) and partially chemically modified were subjected to various physico—chemical investigation methods involving water sorption, contact angle, and protein adsorption measurements. From contact angle data the interfacial free energy γsw between grafted films and water was calculated. It was found that the water uptake of grafted films increases with grafting yield or, in the case of grafted and afterwards chemically modified films, with reaction yield; the diffusion coefficient of water in the modified films also increases with grafting yield. Contact angle studies revealed all grafted films to have surfaces more hydrophilic than the ungrafted trunk polymer. The degree of hydrophilicity—especially of HEMA‐grafted films—strongly depends on grafting conditions. For some grafted samples with high surface hydrophilicity very low interfacial free energies approaching zero were measured. The study of the competitive adsorption of bovine serum albumin, γ‐globulin, and fibrinogen from a synthetic protein solution onto modified films showed that the adsorption of albumin increases markedly with increasing grafting yields, whereas the fibrinogen and γ‐globulin adsorption only slightly increases. A correlation between interfacial free energy and protein adsorption in the sense of the “minimum interfacial free energy hypothesis” was found only for samples with grafting yields below 5%. At higher grafting yields the increased surface area complicates the analysis.
Correlation between microstructure of AgPdAuCu alloy and changes in shape on aging
Authors: Asaoka Kenzo , Tsuji Koichiro , Kuwayama Norihiko 
Published: December 2004

AbstractAn investigation has been carried out to study changes in shape on aging in plastic deformed AgPdAuCu alloys. The changes in shape were measured in order to establish a relationship to the aging heat treatments. Their microstructure was observed in order to clarify this phenomenon at the same time. They were also investigated quantitatively using a feature analysis system. The changes in shape were interpreted as the shrinkage in volume resulting from the formation of the ordered phase. They were smaller at aging temperatures below 673 K. The change in microstructure was different at aging temperature between 573 and 773 K. These phenomena were due to the following: First, nodules which nucleated at the grain boundaries would have grown into the grains well before the formation of the ordered phase, and second, the shrinkage in volume would have been of a different kind that the ordered phase. Therefore aging treatments should be carried out at low temperature in order to minimize the changes in shape. Also, nodular growth should be inhibited in order to maximize the hardening in Ag‐rich alloys.
The influence of dentine on the in vitro cytotoxicity testing of dental restorative materials
Authors: Meryon S. D. 
Published: December 2004

AbstractFew in vitro systems for testing dental restorative materials have taken into account the protection afforded by the residual dentine in vivo. In turn opinions differ as to whether an increase in residual dentine thickness increases this protection. In this study an increase in the depth of dentine powder beneath zinc oxide eugenol (ZOE) reduced its toxicity, while this was not the case with the glass ionomer cement. Compaction of the powder had no effect, suggesting that protection was due to binding of the toxicant to the dentine rather than it acting as a physical barrier. Protein was shown to be very important in moderating the cytotoxicity of ZOE. These results suggest that in vivo the irritancy of some materials may be related to the depth of residual dentine but not others. The effect of exposure period and volume of these materials on their cytotoxicity was also investigated. Increasing the volume of ZOE while retaining the same surface area increased the toxicity of ZOE, while with the glass ionomer it had no effect.
Correlation of tissue reaction to corrosion in osteosynthetic devices
Authors: French H. Graeme , Cook Stephen D. , Haddad Ray J. 
Published: December 2004

AbstractThis study evaluated the interaction of osteosynthetic plates to adjacent tissue. Eleven patients had 13 plates removed with simultaneous biopsies of the adjacent soft tissue. Four patients had pain localized to the area of the plate and 11 patients had routine removal or removal for fracture nonunion. Each plate was graded on a 0–5 point scale for the amount and severity of corrosion present at the screw—plate interface. The adjacent tissue was fixed in formalin and stained with hematoxylin and eosin. The tissue reaction was graded on a 0–5 point scale based on the inflammatory response. A positive correlation of corrosion and tissue reaction was found that was significant at p ≤ 0.005 in the assymptomatic group. The other good correlation showed that tissue reaction tends to decrease with time at p ≤ 0.005. There was no correlation of corrosion with tissue reaction in the symptomatic removal group. All patients with pain adjacent to the plates were relieved by implant removal. The findings suggest that stainless steel is minimally toxic to human tissue in most circumstances and that the toxic products are well tolerated. There was a significant group (4/11) that showed a different pattern of tissue response which did not appear to be toxic response. We do not recommend routine implant removal to prevent metal toxicity; however, there is a group of patients who have pain in the area of the implant that may be caused by an allergic reaction and is relieved by implant removal.
Removable partial denture design: A photoelastic study
Authors: Stewart B. L. , Edwards R. O. 
Published: December 2004

AbstractQuantifiable frozen‐stress photoelastic techniques were used to analyze stresses induced in mandibular models by a conventional free‐end saddle removable partial denture. Four quasi‐anatomical mandibular models were constructed for processing, together with their respective calibration specimens, through identical time/temperature stress‐freezing cycles. After processing and slicing, an unloaded control model demonstrated some low‐order fringes adjacent to the coronal third of the abutment tooth roots, but was otherwise stress free. A lower bilateral free‐end saddle partial denture was constructed and fitted in turn to each of the remaining three models. Each denture/model combination was then loaded and processed through a stress‐freezing cycle. After processing, 6‐mm slices were cut from selected regions for analysis for the presence of stresses. Using a polariscope with circular polarized, monochromatic light, values for maximum shear stress were calculated at selected points in the slices taken from the three loaded models. Variations up to 28% of the mean were obtained for the three experimental models as compared with the consistent results for the material fringe values obtained from the calibration specimens. The study pointed out the problems involved in using photoelastic stress analysis on complicated anatomical models. The interpretation of the results from such studies should be approached with caution.
Materials, clinical and morphological evaluation of custom‐made bioreactive‐glass‐coated canine hip prostheses
Authors: Ducheyne P. , Martens M. , Burssens A. 
Published: December 2004

AbstractBioreactive‐glass‐coated hip prostheses were implanted in dogs for periods of time ranging from 3 to 17 months. The prostheses were tailor‐made for each animal through the use of standard radiographs. However, such a procedure does not necessarily yield a close apposition between the glass layer and bone. As a result, the initial stability of the component can be lost before bone bonding is established. Secondary to this phenomenon, the micromotion can lead to a continuous disruption of the top film on the glass despite the evidence of various reaction layers on the glass surface.
Morphological characteristics of tendon cells cultured on synthetic fibers
Authors: Ricci J. L. , Gona A. G. , Alexander H. , Parsons J. R. 
Published: December 2004

AbstractFilamentous carbon is currently being used as an implant material for tendon and ligament repair in humans. This material acts as a scaffold for the organization of new fibrous tissue growth. Primary cultures of rat tendon fibroblast cells (1° RTF cells) were grown on carbon, Dacron, polyethylene and Nylon fibers in vitro. The morphological characteristics of these cells were examined. The process of cell migration from tendon explant to fiber substrate was similar for all four materials. Three morphological categories of cells were observed on these materials. (1) spherical dividing cells, (2) spindle‐shaped migrating cells, (3) sheath‐like migrating or stationary cells. The morphological characteristics and orientational behavior of cultured fibroblasts on these fiber materials were strongly influenced by the diameters of the fibers and by fiber surface characteristics such as longitudinal striations. The possible mechanisms of cell response to substrate geometric configuration are discussed along with the clinical significance of these experiments.
A calorimetric study of the interaction of synthetic phospholipid liposomes with vinyl monomers, acrylates and methacrylates
Authors: Fujisawa Seiichiro , Kadoma Yoshinori , Masuhara Eiichi 
Published: December 2004

AbstractMono‐, di‐, and trimethacrylates (monomers) are widely used in dentistry as restorative materials, adhesives, prosthetic devices, etc. It is known that the residual monomers released from the cured resin have been implicated in toxicological effects.1 In order to monitor the biological actions at the membrane level induced by monomers, we studied the changes in the phase transition temperature (T) and enthalpy (ΔH) of dipalmitoyl‐phosphatidyl‐choline liposomes induced by 37 different monomers using differential scanning calorimetry (DSC). The monomers that caused large changes in the T and ΔH were vinyl monomers; acrylates; monomethacrylates that contain hydroxy, carbonyl, amino and phenyl groups; dimethacrylates with short‐chain substituents; and aliphatic trimethacrylates. It is suggested that the changes in the T and ΔH values may be due not only to hydrophobic interactions, but also to interactions induced by the double bonds or the functional groups in the monomers. On the other hand, methacrylates with simple alkyl ester linkage and dimethacrylates with bisphenol A groups exhibited the smallest changes. The changes in the T and ΔH induced by highly hydrophobic methacrylates were small due to their slower interaction. These changes in transition properties of liposomes seem to be related to biological activities.
In vivo validation of a cell culture test for biocompatibility testing of urinary catheters
Authors: Graham D. T. , Mark G. E. , Pomeroy A. R. , Macarthur E. B. 
Published: December 2004

AbstractBiocompatibility tests have been compared for their suitability as routine safety tests for urinary catheters. Latex catheters from five manufacturers were tested by each of the following four methods: (1) a cell culture cytotoxicity assay of catheter extracts, (2) intracutaneous injection of the extracts into rabbits, (3) intramuscular implant of catheter pieces into rabbits, (4) catheterization of sheep (mucous membrane irritation). The rabbit intracutaneous and intramuscular tests are both current pharmacopoeial methods for ascertaining the suitability of polymers for medical use. The four tests each showed a cell or tissue response ranging from no detectable change to severe damage, according to the catheter batch or brand, and they each identified the same samples as most toxic and least toxic. However, they differed in sensitivity. The sheep test and the cell culture assay discriminated between catheters of intermediate toxicity and ranked as toxic catheters not identified as such by the two pharmacopoeial tests. The sheep test most closely approximates clinical usage, but is impractical for routine use. The cell culture assay is a suitable alternative. It also has the advantages of a clearly defined endpoint, good sensitivity, reproducibility, speed, and reduced animal usage.
The initial stages of adsorption of plasma derived proteins on artificial surfaces in a controlled flow environment
Authors: Rudee M. L. , Price Todd M. 
Published: December 2004

AbstractSurfaces of amorphous carbon, polystyrene, and polycarbonate were exposed to solutions of fibrinogen, a modified fibrinogen which lacked the alpha chain protuberance, and serum albumin. The results were studied by electron microscopy. The exposures occurred in a well characterized flow environment at a shear rate of 135/s. All three protein species formed a film when adsorbed to carbon films. When the proteins were adsorbed to polystyrene surfaces, formation of a network was observed. Polycarbonate surfaces adsorbed the proteins both as a network and as a continuous film. It was observed that the nature of the adsorption process depended upon the specific combination of molecule and material. For example, on carbon, individual fibrinogen molecules retain their trinodular structure and adsorb randomly until a monolayer forms. On polystyrene, the individual fibrinogen molecules appear as globules and a network forms before complete coverage occurs.
Roughness and thrombogenicity of the outer surfaces of intravascular catheters
Authors: Hecker J. F. , Scandrett L. A. 
Published: December 2004

AbstractThirty‐seven types of catheters made from plastics including silicone rubber, polyvinylchloride, polyethylene, and polyurethane were tested for thrombogenesis in the cephalic vein of sheep. The range in the mass of thrombus on the catheters at autopsy 9 days after insertion was 20‐fold. There was considerable variation when catheters made from the same types of plastic were compared, but polyethylene catheters tended to be more thrombogenic than other types. Scanning electron microscopy (SEM) revealed a variety of surfaces ranging from very smooth to very rough. Roughness was frequently associated with the presence of radioopaque particles which in several catheters were concentrated into radio‐opaque tracer strips. Within types of plastics, catheters with rougher surfaces were usually more thrombogenic than those with smooth surfaces.
The load carrying and fatigue properties of the stem–cement interface with smooth and porous coated femoral components
Authors: Manley M. T. , Stern L. S. , Gurtowski J. 
Published: December 2004

AbstractPorous coated surfaces for fixation of total hip replacement are a current trend in clinical orthopedics. Such devices are designed to be fixed by ingrowth of bony tissue, although in the absence of FDA approval for biologic fixation, fixation with PMMA cement is recommended by the implant manufacturers. In order to characterize the mechanical properties of the microinterlocked stem–cement interface, we tested both porous coated and smooth femoral components in cement mantles of consistent overall geometry. Under conditions of increasing load the smooth stems demonstrated stepwise irreversible subsidence into the mantle. Axial and circumferential strains measured in the cement containment vessels with the smooth stems showed that stepwise increases in tensile hoop strain occurred concomitantly with the stepwise incidents of stem subsidence. When subjected to the same loading conditions, the porous coated stems did not undergo stepwise incidents of subsidence, and hoop strain generation was reduced. In addition, a twofold increase in the failure load of the stem–cement interface was measured with the porous coated stems. Fatigue loading for 107 loading cycles did not result in gross failure of either the microinterlocked or smooth interfaces. However, the data showed that during fatigue loading, stepwise subsidence of the smooth stems again occurred. The final subsidence magnitude of the smooth stem–cement interface at 107 loading cycles was six times greater than the value associated with the porous coated stem. Thus the porous coating of femoral stems was shown to dramatically improve the load carrying capability and fatigue characteristics of the stem–cement interface.
A new glass‐ceramic for bone replacement: Evaluation of its bonding to bone tissue
Authors: Nakamura Takashi , Yamamuro Takao , Higashi Shoichiro , Kokubo Tadashi , Itoo Setsuo 
Published: December 2004

AbstractGlass powders (350 mesh) of the composition MgO, 4.6; CaO, 44.9; SiO, 34.2; PO, 16.3; CaF, 0.5 in weight ratio were compacted, heated to 1050°C at a rate of 5°C/ min and kept at 1050°C for 2 h. The resultant glass‐ceramic having oxyapatite, fluoroapatite, and wollastonite crystals showed high bending and compressive strengths of 157 and 1060 MPa, respectively. The biocompatibility and bonding ability of this new glass‐ceramic to the bone tissue was evaluated using rabbit tibial bones, and the failure load to break the bonding of several ceramics (the new glass‐ceramic, dense hydroxyapatite, 45S5 Bioglass, alumina‐ceramic) to bone tissues was measured. The new glass‐ceramic showed tight bonding to bone comparable with dense hydroxyapatite, and in 25 weeks its load was 70% of that of bone tissue.
Poly(O‐acyl hydroxy L‐proline) (II) wetting characteristics and blood clotting on surfaces of poly O‐acetyl, butyryl, hexanoyl, dodecanoyl, and benzoyl hydroxy L‐proline
Authors: Kawasaki Tadayoshi , Komai Takashi 
Published: December 2004

AbstractPoly O‐acetyl, butyryl, hexanoyl, dodecanoyl, and benzoyl hydroxy L‐proline (poly[O‐acyl Hyp]s) were evaluated as materials for blood contact by means of contact angle and blood clotting time measurements. Critical surface tensions obtained from Zisman plots for all materials were 22–29 dyn/cm, suggesting that these materials may exhibit good blood compatibility. Dispersion and nondispersion force contributions to the surface tension were γ = 1.4, γ = 49.3 dyn/cm, (11.0, 16.2), (19.8, 3.8), (21.2, 4.6) and (14.1, 10.8) for the poly(O‐Acetyl, Butyryl, Hexanoyl, Dodecanoyl and Benzoyl Hyp) surfaces, respectively. The materials showed remarkable wetting differences that were dependent on the type of acyl group attached to Hyp.The values of the dispersion and nondispersion components of the surface tension for poly(O‐hexanoyl Hyp) and poly(O‐dodecanoyl hyp) were very close to those obtained for glutaraldehyde‐treated umbilical cord vessels. The blood clotting times on the respective polymer surfaces, obtained by using the kinetic method, were normalized to those of control glass and siliconized glass surfaces. All the poly(O‐acyl Hyp)s surfaces showed longer clotting times than those of the poly(L‐proline) and glass surfaces. The surfaces of those polymers having longer aliphatic or aromatic acyl groups had longer clotting times than those of the polymers with relatively shorter groups.
Characterization of morphologic and mechanical properties of surgical mesh fabrics
Authors: Chu C. C. , Welch L. 
Published: December 2004

AbstractThe objective of this study is to use standard testing methods to characterize the currently available synthetic mesh fabrics in terms of their chemical, physical, mechanical, and morphologic properties. Three commonly used surgical mesh fabrics, Mersilene (Ethicon), Marlex (Davol), and Teflon (USCI), were used, and the tests reveal that they differ from one another chemically as well as configurationally. The experiment included an identification of the structure of the yarn and fabrics; a measurement of the porosity, pore size and shape; and a determination of tensile and bursting strength, flexural rigidity, and wrinkle recovery. A wide variation in structure and performance was observed among the three mesh fabrics. Mersilene mesh fabrics have the highest relative porosity, while Marlex and Teflon meshes have an equivalent, but lower value. Marlex meshes have the highest tensile and bursting strength followed by Teflon and Mersilene meshes. All three meshes have one common strength characteristic—a distinctive difference in tensile strength between the wale and course directions. Marlex mesh fabrics exhibit an immense flexural rigidity and poor wrinkle recovery, due mainly to the monofilament structure of the yarn. Mersilene and Teflon mesh fabrics have similar but considerably lower, flexural rigidity than Marlex. Thus, it is evident that the chemical nature of the constituent fibers, as well as the yarn and fabric structure, have a great effect on the performance of the resulting mesh fabrics. The availability of this characterization data can serve as the basis for a surgeon's selection of the most appropriate commercial surgical mesh fabric for each case, as well as to provide a foundation for the subsequent comparison of their in vivo performance.