bluuebunny/crossref_metadata_2025_split huggingface dataset:
The quantitation of cultured cellular surface coverage: Applications for transparent and opaque surfaces
Authors: Herring Malcom , Evans David , Baughman Sally , Glover John 
Published: December 2004

AbstractA planimetric technique is described for the analysis of cellular linings cultured on vascular prostheses and tissue culture plates. The method is not destructive of the cells and uses a calibrated eyepiece grid and an inverted microscope. The technique allows a rapid assessment of the percent of the prosthetic surface covered by cells, the average size of the cellular islands, and their distribution. In addition, the cells may be counted, their average surface area computed, and growth curves constructed for cells grown on tissue culture plates without the need for multiple concurrent cultures. Different cell types may be counted on the same surface. The method is more accurate than methods that require the resuspension of cells for counting, and it saves time and cells.
Detection of cyanoacrylate tissue adhesives in histological sections
Authors: Galil K. A. , Schofield I. D. , Wright G. Z. 
Published: December 2004

AbstractPrevious histological studies of cyanoacrylate in wound healing have all used Oil‐Red‐O staining of paraffin sections prepared by routine method. In the course of our studies we began to suspect that artifact was being introduced because of dissolution of cyanoacrylate during processing. Accordingly, biopsis of wounds sealed with cyanoacrylate and pieces of cyanoacrylate of a standard known dimension with no associated tissue were observed after every stage of histological preparation. It was observed that approximately 80% of the cyanoacrylate was lost at the deparaffinization in xylene stage. Accordingly, a number of solvents were tested, and it was found that petroleum ether could be used to remove paraffin completely without the loss of any of the cyanoacrylate from the specimen. This technique has been used to view the location and ultimate fate of cyanoacrylate applied to wounds and examined at different stages in healing process. It is concluded that previous histological studies of cyanoacrylate in wound healing have been inaccurate due to leaching out of most of the tissue adhesive during deparaffinization of the specimen.
Extracorporeal removal of mercury by hemoperfusion through agarose—polymercaptal microsphere beads
Authors: Margel Shlomo , Marcus Leon , Mashiah Aharon , Savin Hillel , Dalit Michael 
Published: December 2004

AbstractUniform agarose—polymercaptal microsphere beads (APMMB) of 1.0‐mm diameter were prepared by encapsulating thousands of polymercaptal microspheres of 0.8‐μm average diameter within an agarose matrix. Those beads show a high avidity and affinity for mercury and readily remove mercury compounds bound to serum proteins. In vivo detoxification trials in dosed rabbits and dogs showed the effectiveness of the APMMB for removal of mercury compounds by hemoperfusion. The rate for mercury removal is enhanced by addition of cysteine. The biocompatibility of the APMMB, measured by the depletion of the formed elements and various soluble components of the blood, is also demonstrated.
The interaction of urea with the generic class of poly(2‐hydroxyethyl methacrylate) hydrogels
Authors: Pinchuk L. , Eckstein E. C. , Van De Mark M. R. 
Published: December 2004

AbstractWork reported here shows that, contrary to reports in the literature, hydrogels made from pure poly(2‐hydroxyethyl methacrylate), pHEMA, at crosslinker content greater than 0.15 mol % do not swell above the usual equilibrium values of 39–42% water content in aqueous urea solution. However, hydrogels containing small (impurity) amounts of methacrylic acid (MAA) do swell dramatically (approximately 90%) in dilute urea solution, but not directly due to the urea. The urea decomposes to produce ammonium ions, thus raising the pH of the solution. Ionization of MAA occurs above pH 6, causing electrostatic interactions within the gel. The grossly swollen state of these gels represents an internal equilibrium among forces due to rubber elasticity, polymer—polymer/solvent affinity, and electrostatic interactions.
Adsorption and reactivity of human prothrombin to artificial surfaces
Authors: Chuang Hanson Y. K. , Mitra Sankar P. 
Published: December 2004

AbstractHuman prothrombin in Tyrode's solution, in mock plasma (albumin, fibrinogen, and IgG mixture), and in citrated plasma adsorbs to Cuprophane, polyvinylchloride, and polyacrylonitrile surfaces. The adsorption of prothrombin is maximal in Tyrode's solution and minimal in plasma. The surface concentrations of prothrombin are highest on polyacrylonitrile, second on polyvinylchloride, and lowest on Cuprophane at all prothrombin concentrations tested in the bulk solution. Qualitative tests show that prothrombin adsorbed to polyvinylchloride can be activated by Taipan snake venom to generate thrombin that clots fibrinogen. However, more quantitative tests indicate that only part of the adsorbed prothrombin on all three materials can be activated to form thrombin exhibiting amidolytic activity. The partial reactivity of adsorbed prothrombin is further confirmed by release of 125I‐peptide from surface bound 125I‐prothrombin after treatment with Australian Taipan snake venom. Prothrombin bound to Cuprophane seems to promote granulocyte adhesion, but has no effect on platelet adhesion.
Direct electron microscopy studies of the bone—hydroxylapatite interface
Authors: Tracy B. M. , Doremus R. H. 
Published: December 2004

AbstractThe bone‐hydroxylapatite interface has been examined directly in the transmission electron microscope (TEM). The bone—hydroxylapatite interface was characterized by using several electron microscopy techniques, including bright and dark field imaging, electron diffraction, high‐resolution imaging, and energy dispersive analysis in the scanning‐transmission electron microscope (STEM EDS). Mechanical grinding followed by argon‐ion milling produced interface regions of unstained and undecalcified rat bone and hydroxylapatite that were transparent to electrons. Thus the exact location of the interface could be established and the bone at the interface studied. Conventional and high‐resolution imaging in the TEM demonstrated direct chemical bonding between bone and hydroxylapatite. The bone at the ceramic surface was the same as normal bone away from the interface.
Difference of bond bonding behavior among surface active glasses and sintered apatite
Authors: Fujiu T. , Ogino M. 
Published: December 2004

AbstractThree types of surface active glasses and sintered apatite were implanted in femurs of rabbits for 8 and 16 weeks and subjected to the push‐out test to measure the bone bonding strength. The apatite surface layers of these materials, which were formed under in vitro treatment, were studied using IR, NMR, and AES. The difference in the bonding strength among these materials was shown statistically. The results of in vitro experiments explained the differences. It was concluded that the crystal chemistry and formation rate of the surface apatite layer significantly influenced the bonding strength. Materials that formed a surface apatite layer having a bone‐like crystal chemistry and fast formation rate showed high bone bonding strength.
Molecular weight characterization of virgin and explanted polyester arterial prostheses
Authors: Maarek J. M. , Guidoin R. , Aubin M. , Prud'homme R. E. 
Published: December 2004

AbstractThe macromolecular properties of 17 virgin commercial arterial prostheses and a series of explanted prostheses, both manufactured from poly(ethylene terephthalate) (PET) yarns, have been studied by gel permeation chromatography (GPC) and by differential scanning calorimetry (DSC). Only small differences were found between the average molecular weights and the degree of crystallinity of the unused reference grafts. A broadening of the DSC curves was observed for the prostheses containing texturized yarns compared with those made solely from flat, untexturized yarns. This broadening may be due to greater heterogeneity of the crystal sizes caused by the texturizing process and to the use of two or more different yarns with dissimilar thermal histories in the same prosthesis. Average molecular weights of the explant series were significantly lower than those of the corresponding reference grafts but almost time independent. The polydispersity index and the degree of crystallinity of the explants remained constant as a function of time. These results are discussed in regard to others available in the literature.
Cytocompatibility of albuminated polyester fabrics
Authors: Sigot‐Luizard M. F. , Domurado D. , Sigot M. , Guidoin R. , Gosselin C. , Marois M. , Girard J. F. , King M. , Badour B. 
Published: December 2004

AbstractAn alternative to the usual technique of preclotting porous textile vascular prostheses prior to surgical implantation is to render them impermeable to blood by impregnation with a cross‐linked albumin filler matrix. This material subsequently becomes the foundation for cellular development. The compatibility of such impregnated fabrics with newly formed endothelial cells has been evaluated by an in vitro organotypic culture method. This technique enables the characterization and numeration of cells that develop on blood contact surfaces and enables determination of their rate of development. Woven, knitted, and velour fabrics were evaluated folllowing coating with albumin and either storage in Tyrode solution or 40% ethanol or desiccation by critical point drying. Preclotted cardiovascular repair fabrics prepared according to conventional surgical protocol served as controls. The identification of the newly formed cells was confirmed histologically. The most extensive and rapid cellular development was observed on the woven fabric and is believed may have resulted from the smoother surface topography of this substrate. Good cellular development was noted particularly on fabrics which had been stored in Tyrode solution. Ethanol had a deleterious effect on the apparent compatibility.
The activation of the complement system by polymer materials and their blood compatibility
Authors: Sevast'ianov V. I. , Tseytlina E. A. 
Published: December 2004

AbstractThe activation of the complement system by polymer materials and their blood compatibility. One of the negative effects of the clinical application of various blood‐containing biomedical devices is the activation of the complement system induced by a foreign surface. A method of determining the hemolytic activity of human serum complement before and after contact with polymers was chosen in order to elucidate the relationship between polymer surface types and the degree of complement activation. The complement activation of each donor proved to depend both on his own complement reactivity and the type of polymer surface. The role played by each constituent was estimated using the rate constants for spontaneous (ksp) and induced (kind) complement activation. The negative correlation (−0,88, p < 0,001) between the degree of irreversible adsorption of 131I‐serum albumin and relative kind was determined. Thus, we propose the use of kind for the criterion of conformation alterations of protein macromolecules induced by the adsorption/desorption processes on blood/surface interface, leading to complement activation.
The binding of metal salts and corrosion products to cells and proteins in vitro
Authors: Merritt K. , Brown S. A. , Sharkey N. A. 
Published: December 2004

AbstractThe binding of metal ions from salts and from corrosion products of 316 LVM stainless steel and MP‐35 to blood cells and serum proteins was studied in vitro. In the first series of experiments, metal salts were added to whole blood and then the blood separated into red cells, white cells, and serum. Nickel from nickel chloride or corrosion products of stainless steel bound in very small quantities to blood cells. Cobalt from cobalt chloride bound to both red cells and white cells. Chromium from chromic chloride (Cr3+) bound to cells in very small quantities whereas chromium from potassium dichromate (Cr6+) and corrosion products showed very high to binding to red cells and some binding to white cells. In a second series of experiments the blood was separated into its components and then the metal salts were added and the binding pattern was identical. In a third series of experiments serum which had interacted with the metal salts or corrosion products was separated into its components by isolectric focusing on polyacrylamide gels. Almost all of the metal, whatever the source, was detected in the albumin region of the gels indicating strong binding to albumin. These studies on the cell and protein binding of the metals help to explain the dissemination of corrosion products from the site of the implant and subsequent systemic responses by some individuals.
The fatigue strength of porous‐coated Ti–6% Al–4% V implant alloy
Authors: Yue S. , Pilliar R. M. , Weatherly G. C. 
Published: December 2004

AbstractThe fatigue behaviour of Ti‐6Al‐4V (extra low interstital) alloy coated with Ti‐6Al‐4V powder was investigated using rotating bending fatigue testing. It was found that the high cycle fatigue strength of porous coated specimens exhibited a substantial decrease compared to uncoated specimens of the same microstructure. Chemical analysis of the sintered surface revealed significant increases of interstitials compared to the bulk analysis, but it is concluded that this would not adversely affect the fatigue strength. Scanning electron microscopy revealed crack initiation close to particle/substrate contact interfaces and it is concluded that stress intensification due to these interface regions are major sources of weakness with respect to fatigue strength. Finally it was found that subjecting a polished Ti‐6Al‐4V specimen to the heat treatment required for sintering resulted in delineation of prior beta grain boundaries and it is suggested that this also contributes to the inferior fatigue strength of porous coated Ti‐6Al‐4V.
The antithrombotic effect of prostaglandin E1 immobilized on albuminated polymer matrix
Authors: Chandy Thomas , Sharma Chandra P. 
Published: December 2004

AbstractFor intravascular implantation, a biofunctional surface seems to retard surface thrombosis upon synthetic materials. Prostaglandins, like PGI2, PGE1, and PGD2, etc., are believed to stimulate membrane‐bound adenyl cyclase and thereby raise intracellular levels of c‐AMP within platelets, which inhibit platelet adhesion and aggregation. A new procedure is suggested for the immobilization of prostaglandin E1 on an albuminated polymer matrix, through glutaraldehyde coupling. Materials thus prepared show dramatic antiplatelet effects, with regard to platelet adhesion, when compared with albumin‐immobilized surfaces. The affinity of various modified surfaces toward platelet adhesion is studied, using washed platelets suspended in Tyrode's solution. Octane contact angle studies are used to develop an understanding of the varied nature of bound substrates at equilibrium on polymer surfaces. These are studied at the solid/liquid interface, which is closest to in vivo conditions. The plasma recalcification time demonstrates the anticoagulant properties of various surfaces. A possible role of PGE1 in reducing platelet activity in the presence and absence of vitamin C is discussed. This technique may be used in the development of nonthrombogenic surfaces on existing biomedical polymers. Simultaneous pharmaceutical modification of the blood with vitamin C may enhance the blood compatibility of the surface.
Extracorporeal removal of specific antibodies by hemoperfusion through the immunosorbent agarose‐polyacrolein microsphere beads: Removal of anti‐bovine serum albumin in animals
Authors: Marcus Leon , Mashiah Aharon , Offarim Michael , Margel Shlomo 
Published: December 2004

AbstractWe describe (1) the production of a unique immunosorbent system, agarose‐polyacrolein microsphere beads (APAMB) for removal of a specific antibody, anti BSA, and (2) its efficacy in animal trials. This is a model system for hemoperfusive removal of specific antibodies or antigens directly from whole blood. The agarose beads (1.0 mm mean diameter) contain thousands of microspheres of 0.2 m̈m mean diameter. The microspheres which contain the ligand are encapsulated within an agarose matrix to confer physical strength, biocompatibility, spacial configuration, and porosity allowing rapid entry of plasma for reaction. Any antigen may be linked covalently to spacers on the polyacrolein microspheres to remove a specific antibody, or vice versa. Thus the APAMB remove specific molecules in contrast to the charcoal or ion exchange resins currently in use. Removal of antibody is efficient and rapid, therefore, short hemoperfusive times may be used. The beads are biocompatible; there are negligible decreases in RBC, WBC and platelets. Electrolytes and other soluble components also are minimally affected. Therapy, at the least palliative, of autoimmune disorders i.e., multiple myeloma, macroglobinemia, autohemolytic anemias, idiopathic thrombocytopenia, myasthenia gravis, rheumatoid arthritis, thyroiditis, glomerulonephritis, etc, is potentially available with this or its further improved versions.
In vivo biocompatibility studies. V. In vivo leukocyte interactions with biomer
Authors: Marchant R. E. , Miller K. M. , Anderson J. M. 
Published: December 2004

AbstractA cage implant system was utilized to quantitatively and qualitatively characterize in vivo leukocyte interactions with cast Biomer. Scanning electron microscopy (SEM) in conjunction with cytochemical staining procedures were used to investigate the cellular events at the leukocyte/Biomer interface as well as in the inflammatory exudate over a 21‐day implantation period. SEM was used to characterize leukocyte morphology on the Biomer surface and the cytochemical stains were used to differentially count leukocytes and to demonstrate intracellular alkaline and acid phosphatase activity. The results showed that the population density of leukocytes on the Biomer surface diminished with implantation time. The population density of multinucleated foreign body giant cells remained constant with time, while the numbers of nuclei per giant cell increased. The differential analysis revealed that macrophages preferentially adhered to the Biomer surface compared to other leukocytes in the exudate. The phagocytic capability of all adherent leukocytes, including giant cells, decreased with time and this corresponded to changes in leukocyte morphology observed with SEM.
In situ replication techniques: II. Quantitative methodologies for replicate materials
Authors: Kusy R. P. , Whitley J. Q. 
Published: December 2004

AbstractBecause replicate materials have requirements different from those of recording or impression materials, quantitative methodologies were sought using commercial impression materials. Two satisfactory objective techniques resulted, a laser‐scattering and a capillary flow test. Using high‐resolution gratings to simulate tooth detail (<1 μm), the reproduction quality of 36 two‐stage replicas was determined in diffraction, reflection, and in an unblazed state. Using precision bore glass tubes (0.25, 0.5, 1, and 2 mm diameters) to simulate the high‐energy surface of enamel, the flow characteristics of nine elastomers (the first stage replicates) and four epoxies (the second stage replicates) were determined at isobaric conditions. Because the laser spot size was relatively large (0.6 mm) and the pressure differential was small (25 mm Hg), both the global resolution and the low shear rate characteristics could be measured. Of the commercial materials tested, Reprosil Light had the best combination of fluidity and resolution, regardless of which positive material was used. Although Permagum Low, Silene Wash, and Xantopren Blue scored high in one of the two tests, none of these materials could compare to Reprosil Light within the context described herein.
Assessment of thromboresistance of intravenous cannulae by 125I‐fibrinogen scanning
Authors: Lewis J. , Sweeney J. , Baldini L. , Friedland G. H. , Salzman E. W. 
Published: December 2004

AbstractAssessment of potentially thromboresistant polymers and other materials has been impeded by the lack of a simple and safe test procedure in man. This report describes the use of a portable gamma radiation detector to assess accumulation of 125I‐fibrinogen in thrombi related to intravenous cannulae. The method was first employed in 19 dogs and one sheep with FEP‐Teflon forelimb intraveneous cannulae which were scanned for up to 6 h after insertion. Results were compared with findings at post mortem examination. Eleven thrombi developed, nine of which emitted more than 3500 counts per minute; eight of these (89%) were detected by external scanning. The smallest thrombus detected weighed 0.7 mg. The method did not distinguish between thrombus and hematoma. Fifty FEP‐Teflon cannulae were then studied in 39 patients after injection of 100 μCi 125I‐fibrinogen. Cannulae and control sites were scanned twice daily and an independent blind clinical appraisal was performed by an experienced nurse. A rise in percentage uptake (count at a limb site/heart count × 100) of 20 or a difference of 40 between adjacent sites was regarded as a positive test. Scans became positive up to 30 h before clinical evidence of phlebitis was observed. The interval between insertion and thrombosis of both large and small cannulae detected by scanning was significantly shorter than that determined by clinical assessment (p < 0.001). Physical signs of phlebitis were noted with 58% of large cannulae (16 or 18 gauge) and 33% of small cannulae (22 gauge) at the time of removal. Positive 125I‐fibrinogen tests were obtained with 70% of large cannulae and 75% of small cannulae. 125I‐fibrinogen scanning is a safe simple sensitive technique to detect thrombosis related to intravenous cannulae. The test should enable comparisons of different cannula materials in man.