bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interaction of blood and tissue cells with foreign surfaces
Authors: Johnsson‐Hegyeli R. I. E. , Hegyeli A. F. 
Published: December 2004

AbstractThe compatibility of candidate implant materials with living cells was evaluated in vitro. The materials and their interaction with living human blood and tissue cells were observed, recorded, and analyzed by means of reflected light interference microscopy. Blood cells–materials interfaces were prepared by incubating the materials in contanct with whole blood or platelet‐rich plasma. The interaction between the materials and the cells was examined either in a static or a dynamic flow system, and recorded by photography or cinemicrography. The tissue cell–materials interfaces were prepared by cultivating animal and human cells as a monolayer directly on the surface of the material to be evaluated. The resulting implant–cell specimens are suitable for histological fixation and subsequent analysis by modern evaluation techniques such as scanning electron microscopy and elemental analysis by electron microprobe. These studies can be performed on the same implant specimen before, and following its exposure to the biological material. Furthermore, separate analyses of the implant and biochemical analyses of the cells and culture medium can be carried out before and after the interaction. These techniques have been used to investigate the interaction of blood and tissue cells with a variety of promising implant candidate materials such as polymers, metals, glass, and carbon surfaces. As a result of these studies, a number of observations have been made which may be of practical significance to the design engineer in developing and evaluating the safety of prosthetic materials for use in the human body.
Adsorption of plasma proteins in solution to uncharged, hydrophobic polymer surfaces
Authors: Brash J. L. , Lyman D. J. 
Published: December 2004

AbstractInfraref internal reflection spectroscopy has been used to study the adsorption of certain plasma proteins on a variety of hydrophobic polymer surfaces. The behavior of the systems studied was almost identical. Under Static conditions the proteins appear to be rapidly adsorbed as monomolecular layers from solutions varying in concentration between a few mg‐% and normal plasma levels. These monolayers are deduced to be closely packed arrays in which the protein molecules appear to retain their native globular form. The bearing of these results on the mechanism of surface‐induced coagulation is significant.
Evaluation of synthetic fabrics as artificial skin grafts to experimental burn wounds
Authors: Spira Melvin , Fissette Jean , Hall C. William , Hardy S. Baron , Gerow Frank J. 
Published: December 2004

AbstractAfter utilizing the nylon velour Silastic and polypeptide laminates in this experimental pilot study, we can conclude the following:
Both nylon velour Silastic and polypeptide laminates are well tolerated in the clean wound and serve as a satisfactory framework into which fibroblastic proliferation can occur resulting in adherence or take.
In contaminated wounds, infection resulted in exudation with an accumulation of fluid at the interface of granulation tissue and velour. The exudate, not resorbed and unable to transcend the laminate barrier completely, serves as a nidus of progressive bacterial growth and causes separation and rejection of this synthetic fabric cover. The fluid accumulation appeared more common utilizing the Silastic laminate, while the polypeptide laminate appeared to permit an escape of this exudate to inhibit or delay the separation.
The Silastic laminated velour became firm and inflexible, predisposing with motion, to a mechanical type of separation at the margin of fabric and normal skin, possibly a contributing factor in exogeneous infection. This was seen also with the polypeptide laminate, but to a much lesser degree.
The nylon velour Silastic laminate as it is presently constructed is not acceptable as a synthetic skin cover for an infected burn wound, while the polypeptide laminated velour appears to possess physical properties which make it suitable for further investigation as an artificial skin substitute.
Corrosion and fracture of type 316 SMO orthopedic implants
Authors: Colangelo V. J. , Greene N. D. 
Published: December 2004

AbstractOrthopedic appliances of type 316 (SMO) stainless steel were examined in detail after being removed from human subjects. Techniques included conventional microscopy with various lighting methods, together with electron microscope fractography. Corrosion, fatigue failure, and manufacturing defects were identified and statistically tabulated. Corrosion damage occurred on 91% of all multicomponent devices and the overall incidence of fracture failure was 9%. These results indicate an urgent ueed for stronger, more corrosion‐resistant implant alloys.
The effect of α‐cyanoacrylates on wound healing
Authors: Houston Stuart , Hodge John W. , Ousterhout Douglas K. , Leonard Fred 
Published: December 2004

AbstractThe use of cyanoacrylate tissue adhesives provides a quick method of closing wounds by nonsuture techniques. This study was undertaken to determine the relative effects on healing of a number of alkyl α‐cyanoacrylate tissue adhesives compared to sutured incisions. Tissue bonds were prepared with the alkyl α‐cyanoacrylate adhesives and sutures and tested for bond strength in vivo in rats over periods of 1, 3, 7, 10, and 14 days. A trend of increasing bond strength with the higher homologs was immediately apparent. However, this trend was reversed at the time of the 14 day measurements with the higher homologs of the cyanoacrylate adhesives having the lower bond strength. Microscopic examination of pulled wounds closed with methyl α‐cyanoacrylate showed the cause to be substrate failure with the exception of the one hour postoperative samples which demonstrated adhesive failure. Wound failure in the remaining three monomers was cohesive, gradually decreasing to substrate failure at 10 days postoperative. The tensile strength of all wounds closed with tissue adhesive dropped considerably on the third day postoperative.
Some chemical and biological characteristics of a new collagen–polymer compound material
Authors: Chvapil M. , Holuša R. , Kliment K. , Štoll M. 
Published: December 2004

AbstractA new compound material is described, consisting of collagen sponge and glycol methacrylate, with a density varying from a compact to a highly porous spongelike material. Mechanical properties, swelling capacity, trypsin digestion rate, structural stability, and dynamics of tissue reactivity after subcutaneous and subperiostal implantation of this material were compared with collagen sponge, and the glycol methacrylate polymer alone. It has been shown that combined polymer collagen sponge with high porosity is quickly penetrated by connective tissue which maintains the character of highly vascularized loose connective tissue. The porosity of the material is a decisive factor for tissue permeation and the size of the pores should exceed 100 μ. The combination of the glycol methacrylate polymer gel with a collagen sponge increases the mechanical strength of this hydrophilic material. Optimal conditions for construction of the gel–collagen sponge were found.
Growth twinning in γ‐crystals of the silver–mercury system
Authors: Baird H. Wallace , Muller Fredrik A. 
Published: December 2004

AbstractA study by single crystal, x‐ray diffraction methods of a silver amalgam known as “arbor dianae” has shown it to be twinned on the [111] cubic crystal planes. Otherwise, they are identical to the material known mineralogically as moschellandsbergite or the γ‐phase in dental amalgam and the γ1‐phase in the silver–mercury system.
Surgical suture–porcine subcuticular tissue interaction
Authors: Homsy C. A. , Fissette J. , Watkins W. S. , Williams H. O. , Freeman B. S. 
Published: December 2004

AbstractIn this study tissue–suture interaction was evaluated in terms of instantaneous stress and total work at withdrawal, histological response, and photomicrographic suture appearance. Porcine subjects and subcuticular incision closures identical to those of clinical plastic surgery were used; implant periods were 1, 2, and 3 weeks. Monofilamentary sutures (4‐0) of nylon, linear polyethylene, polypropylene, and Teflon FEP were used; stainless steel and braided siliconized silk were included for comparison. Perisutural sleeves, formed by ingrowth of epithelium up to 1 cm from the loci of emergence of the suture through epidermis, were found to account for 70–85% of withdrawal work. The subcutaneous closure is superior to interrupted or running stitches in minimizing these “end effects” and attendant exacerbation of tissue–suture interaction. The degree of the latter combined with consideration of suture strength, suppleness, and knot durability indicate that nylon and Teflon FEP monofilaments are sutures of choice for cutaneous closure.
Surface deactivation of porous glass membranes
Authors: Messing R. A. , Weisz P. F. , Baum G. 
Published: December 2004

AbstractProtein solutions exposed to porous glass membranes are rapidly depleted of protein. The proteins do not migrate through the membrane, but become trapped at the channel walls. Surface deactivation of porous glass can be accomplished by treatment with methyl trimethoxysilane or γ‐aminopropyl triethoxysilane. Bacitracin slowly transferred through a surface deactivated porous glass membrane.
Nucleation and oriented crystallization apatite in ionotropic gels
Authors: Thiele Heinrich , Awad Aida 
Published: December 2004

AbstractWe regard and handle intercellular tissue like gels with ordered fiber molecules. By this preparative histolysis and histogenesis the formation of bone and tooth can be looked upon as a chemical reaction of a cell‐secretion with the interstitial liquid seen as colloidal. The symplex alginate–collagen was directed by diffusion of Ca and H ions and then mineralized like bone and tooth. Collagen in the symplex with alginate gives big pores similar to the spongiosa of bone. Implantation in animals shows healing without rejection and inflammation. The ionotropic gel for a leading structure was remineralized and calcified with hydroxyapatite. Higher temperature gives better crystals by the increasing rate of diffusion and recrystallization. By alternately changing waves of phosphate and calcium, the content of calcium phosphate of the ionotropic gels could be increased to 50%. The mechanical stability was then increased. Waves of ions cause a shrinking of the gel at the same time. This is the reason for the high stability of bone and tooth, shell and pearl. Citrate favors the transformation of the secondary phosphate Brushit into apatite even at room temperature. X‐Ray diffractions of these crystals show the formation of 90% apatite in ionotropic gels by directed intermicellar crystallization, and only 10% Brushit.
Employment of hydron polymer antibiotic vehicle in otolaryngology
Authors: Majkus V. , Horáková Z. , Výmola F. , Štol M. 
Published: December 2004

AbstractHydrophilic poly (glycolmethacrylate) HydronU. S. Trade Mark, National Patent Development Corporation, 375 Park Avenue, New York, N. Y.
gels were used as vehicles for selected antibiotics. Polymer vehicles with various antibiotics were prepared and their biological activity tested by sensitivity tests on solid and liquid media by means of reference microbe strains. Polymer vehicles with chosen antibiotics were implanted in rats and the rate of diffusion tested in vivo by removing the vehicles at fixed time intervals and ascertaining the content of the remaining antibiotic in the vehicle. In the clinical part, the favorable results of application of antibiotics saturated gel vehicles in tympanoplastic operations and healing of inflammatory states after middle‐ear operations are described.
Corrosion under stress of materials composing dental amalgam
Authors: Johnson L. B. , Lawless K. R. 
Published: December 2004

AbstractCorrosion potentials of materials composing dental amalgam have been measured in artificial saliva as the specimens were subjected to an increasing tensile load. Further, tensile tests have been carried out on specimens which had been previously subjected to controlled corrosion.The corrosion potentials of Cu, Ag, Zn, Ag2Hg3, Ag3Sn and finished dental amalgam showed only a slight increase in the anodic direction as the load increased. The potentials of Sn and Sn amalgams, on the other hand, showed a considerable increase.Most of the above results were explained as being a consequence of the rupture and repair of protective films as stress was applied or released. For Sn, however, it was necessary to postulate a complex attack by the corrodant to explain the large potential change.Of the phases of dental amalgam whose tensile strengths were measured after subjection to controlled corrosion, only the γ2 or Sn‐Hg phase was affected. Its strength was lowered by corrosion, whether or not stress was applied.It was concluded that stress, as such, probably is not a direct factor in the corrosion of dental amalgam under oral conditions.
Collagen membrane for hemodialysis
Authors: Kon Tadamasa , Mrava Gene L. , Weber David C. , Nosé Y. 
Published: December 2004

AbstractCommercially available collagen membrance was evaluated as a hemodialysis membrane in the Kolff quad‐coil artificial kidney. The inherent physical weakness of the membrane was strengthened by a double‐screen support substracture in a coil. Greater metabolite clearance and ultrafiltration (over four times) were demonstrated with the double‐screen‐supported collagen coil than with either cellophane or cuprophane membrane supported by the same double‐screen support substructure.
Hemolysis associated with plastics—A histopathologic study with polyurethane
Authors: Rigdon R. H. 
Published: December 2004

AbstractPolyurethane implanted subcutaneously in mice and rats is accompanied by a chronic granulomatous reaction in which there is an excessive amount of hemosiderin. Preceding the occurrence of hemosiderin, many erythrocytes are present, some of which are partially creatinated. Hemosiderin apparently results from the lysis of these red cells. It is suggested that this infiltration of erythrocytes and subsequent hemolysis may result from a positive charge associated with this plastic, attracting the negative charged blood cells. A similar reaction occurs with fragments of nylon and Teflon. There is no significant number of erythrocytes or hemosiderin, however, associated with the inflammatory reaction accompanying carbon black, glass beads, resin or Fuller's earth.
The design of cannulas for maintenance hemodialysis
Authors: Leith W. C. , Cole J. J. , Blagg C. R. 
Published: December 2004

AbstractBecause the Silastic‐Teflon cannulas used for maintenance dialysis are far from ideal, usually failing in less than 1 yr, the factors affecting pressure drop in the cannula system have been evaluated theoretically and confirmed by actual measurements in vitro. Total pressure drop results from fluid friction, boundary layer separation and wall damping, and these effects are related directly to cannula size, shape, and material. By appropriate attention to these factors in cannula design, pressure drop in the system can be minimized. Soft Silastic tips for cannulas have been developed but show disappointingly slow flows and early clotting. These results are readily explained in terms of increased wall damping with soft materials. Commercially available hard Silastic cannula tips may be more satisfactory. Optimal cannula design requires large diameter cannula bodies, suitably shaped cannula tips, and the use of stiff tip materials. Such cannulas should allow the achievement of high blood flows with a minimum of boundary layer separation at the tip‐vessel junction and will be helpful in the prolongation of cannula life.
Ag‐Sn‐Hg alloys as electron compounds
Authors: Johnson L. B. 
Published: December 2004

AbstractThe extraordinary stability of the γ1 phase of dental amalgam was believed to indicate that part of the Sn in dental amalgam was contained in this phase. By extending the Hume‐Rothery “electron compound” ideas to the three component Ag‐Sn‐Hg system, an estimate was made of the amount of Sn which could be held in the γ1 structure.A Ag‐Sn alloy containing 9.1 weight per cent Sn was prepared, spheroidized, and sized. Portions were amalgamated and molded into tensile specimens, parts of which were subjected to X‐ray diffraction, corrosion tests, and tests to determine amalgamation rate and dimensional changes during setting.X‐ray diffraction patterns showed a complete absence of the γ2 phase, (thus indicating that all Sn was in the γ1 phase) and a stability intermediate between γ Ag‐Hg and the γ1 phase of dental amalgam. Physical tests showed a low amalgamation rate, low 1‐hr strength, high 7‐day strength, and high corrosion resistance.
The absorption of carbon dioxide by thin films containing an ion exchange polymer
Authors: Wolfe Ralph G. , Miller Irving F. , Gregor Harry P. 
Published: December 2004

AbstractA thin polymeric film, containing a basic polyelectrolyte, was developed with properties that potentially make it highly suitable for use in a membrane blood oxygenator. Its CO2 absorption capacity was correlated as a function of the CO2 partial pressure, temperature and relative humidity of the processed gas. The correlation showed a linear dependence with CO2 partial pressure and relative humidity and an Arrhenius dependence with temperature. A four‐step mechanism for the absorption process was postulated and its parameters were evalutaed. The apparent diffusion constant for CO2 was five times that measured for an ion‐exchange resin made from the polyelectrolyte. The capacity and mechanism correlations obtained are suitable for the design of a CO2 removal unit for a recirculated air atmosphere as well as for a blood oxygenator. The permeability of the film to CO2 and O2 was measured and the ratio was found to be far greater than that of most commercial materials. This suggests that a blood oxygenator utilizing such a film would have the controlling resistance to transfer on the oxygen side, rather than on the blood side, thus perhaps avoiding bubbling on the blood side altogether.
Potential of ceramic materials as permanently implantable skeletal prostheses
Authors: Hulbert S. F. , Young F. A. , Mathews R. S. , Klawitter J. J. , Talbert C. D. , Stelling F. H. 
Published: December 2004

AbstractThe feasibility of the use of porous ceramic materials in the permanent repair of skeletal defects was studied from the standpoint of physiological compatibility and in growth of natural bone. High‐fired calcium aluminate samples in the form of quarter‐inch diameter cylindrical pellets containing interconnecting porous networks were implanted in vivo into canine femurs for 4‐, 11‐, and 22‐week periods. The implants had 65% porosity with pore size falling within one of five distinct ranges from less than 45 μ to about 200 μ in diameter.Thin sections were prepared by grinding (poly) methyl methacrylate‐mounted cross sections of the femurs containing the implanted ceramic samples and adjacent soft tissues. Tissue‐prosthetic compatibility was determined using standard histological thin section procedures, electron microbeam probe examinations, autoradiographic techniques, microfadiographic techniques, microchemistry techniques, and ultra‐violet fluorescent techniques. Optical microscopic evaluations of each section showed the ceramic samples to be bound lightly by natural bone and gave no detectable signs of tissue incompatibility. Minimum pore size for significant ingrowth of natural bone was indicated to be between 75 and 100 μ.
The role of organics in metallic passivation
Authors: Svare C. W. , Belton G. , Korostoff E. 
Published: December 2004

AbstractOrganic substances are known to affect electrochemical reactions. The passivation characteristics of iron have been shown to be drastically altered in the presence of certain ions. Since passivation must occur to preserve the physical integrity of some materials in vivo, a study was initiated to determine the effect of alanine, bovine plasma albumin, and cystine on this phenomenon for nickel and copper.The procedure was as follows: (1) potential pH diagrams which show stable metal‐containing forms with respect to pH and electrical potential were constructed to interpret anodic dissolution data; (2) measurements were made to determine potential ranges in which organic adsorption occurs; and (3) data on electrical potential of the metal and associated current were taken for construction of anodic dissolution curves.The results showed that the presence of cystine inhibited the passivation of nickel and improved the passivation tendency of copper. The other organic substances had little or no effect on passivation. A possible mechanism for these effects is proposed. Further, the results showed a relationship between the onset of passivation and the potentials where metal‐containing solid substances become thermodynamically stable, as determined from the potential pH diagrams.
In vitro performance of the disposable kiil envelope
Authors: Lips Paul , Kon Tadamasa , Weber David , Mrava Gene L. , Nosé Yukihiko 
Published: December 2004

AbstractFor patients performing hemodialysis at home the assembly of the artificial kidney must be simple. To achieve this, a disposable envelope, consisting of two membranes bonded to a supporting substructure, was developed for the Kiil artificial kidney. This envelope was testedin vitrofor metabolite clearance, pressure‐flow relationship, ultrafiltration, and priming volume. The clearance of this envelope for different metabolites proved to be higher than that achieved with conventional assembly of the Kiil with wet Cuprophan membranes. Analysis of the resistance to mass transfer indicated that the disposable envelope has decreased the blood‐ and dialyzate‐side resistances and provides an increase in effective membrane area, thereby enhancing overall mass transfer. The envelope also showed higher resistance to blood flow and a lower priming volume.In vitrotesting of this envelope has shown the feasibility of practical clinical application.
Test systems for evaluation of cyanoacrylate tissue adhesives
Authors: Katz Abraham R. , Woodward Stephen C. 
Published: December 2004

AbstractA series of tests permitting evaluations of cyanoacrylates as tissues adhesives is presented. Closed coaption of skin is an effective, rapid screening test capable of identifying weak and strong adhesives under use conditions, and is more sensitive for this purpose than bond strength determinations employing aortic lap joints. Tensile strength testing employing skin incisions closed with cyanoacrylates permits evaluation of the continuing effects of cyanoacrylate upon healing skin. In this test system, a number of alkyl cyanoacrylates provides results equivalent to those obtained with sutures. The incorporation of cyanoacrylates into subcutaneous implants permits evaluation of the effects of these materials upon fibroplasia and collagen elaboration, the most critical aspects of wound repair. Implant testing also permits estimation of rates of resportion of cyanoacrylates from subcutaneous deposits.
A stress‐deformation model of the human aorta
Authors: Krokosky E. M. , Krouskop T. A. 
Published: December 2004

AbstractA finite element stress‐deformation model of the human aorta was developed based on previously determined constitutive relationships. The model was used to predict the deformations experienced by an arota when subjected to localized pressure distributions. The model was further refined so as to analyze a twolayered vascular system. The stress distribution through the wall, particularly at the layer interface, was studied for composite vascular systems subjected to localized internal pressures.