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  • 1
    Electronic Resource
    Electronic Resource
    The search for correlation between electrokinetic phenomena and blood thrombus formation on implant materials (1968)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968), S. 51-79 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Bioelectric charge transfer at the blood-wall interface may be a crucial factor affecting thrombosis on implant materials. A program of studies was conducted to determine the electrokinetic and other physical properties of a wide spectrum of materials including organic polymers, metals, inorganics, heterogeneous compounds, and animal tissue. From these tests, materials were selected for in-vivo cannulation experiments. In this manner, a search was made to find a correlation between surface charge characteristics and thrombosis on cardiovascular implant materials. It was found that materials exhibiting a substantial positive charge were prone to rapid thrombosis. No clear correlation can be stated, as yet, regarding the thrombogenecity of highly charged negative surfaces or slightly charged surfaces. However, many heterogeneous materials have exhibited prolonged in-vivo patency. It appears necessary to isolate surface effects from volumetric effects to seek the role of bioelectric charge transfer in blood thrombus formation.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820020105
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  • 2
    Electronic Resource
    Electronic Resource
    The search for the nonthrombogenic property of colloidal graphiteThis work was supported by a grant from The John A. Hartford Foundation, Inc. (1970)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 4 (1970), S. 121-138 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The nonthrombogenic property of the graphite-Benzalkonium-heparin surface has not been consistently attained by those using this coating. In addition, there is mounting evidence that this property is not dependent entirely on the presence of heparin. A series of tests were conducted to further define the properties of colloidal graphite materials, methods of control and possible relationships to thrombus formation. These tests included electrokinetic investigations, dielectric measurements and other physical/chemical property evaluations. It was found that the colloidal graphite coating approximates many properties which are characteristic of animal tissue. However, considerable scatter in the duplication of these properties was encountered. The properties which seemed to separate the Acheson Colloids Company DAG-35 coating from other graphite products were those of porosity and permeability. Control of these parameters may be critical to achieving consistent uniform success.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820040111
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  • 3
    Electronic Resource
    Electronic Resource
    Biocompatibility of ceramic implants in soft tissueThis research was sponsored by grants from the Ferro Corporation and The National Science Foundation-Science Development Program Grant No. GU-01145 to The Center for the Study of Materials and the National Institutes of General Medical Sciences Grant No. 2PO1 GM14267-05 to the Engineering Design Center, Case Western Reserve University, Cleveland, Ohio. Dr. S. D. Davis' research was supported by a National Institutes of General Medical Sciences fellowship No. 1FO2 GM44720-01. (1972)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 6 (1972), S. 425-449 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The degradation and biocompatibility of seveal commercially available glasses, glass-ceramics, and ceramics have been evaluated in soft tissue. Tissue compatibility was investigated by histological and toxicological determinations. Materials degration was evaluated by weight loss and surface replica electron microscopic techniques. High lead and arsenic-selenium-sulfur glasses are found to be unsuitable materials for implantation due to high corrosion and toxicity. Certain borosilicate glasses are also found unacceptable because of severe corrosion. Fused quartz, aluminosilicates, certain borosilicates, alkali resistant glass, soda-lime glass, titania frit, arsenic trisulfide, lithium and magnesium aluminosilicate, glass-ceramics, and calcium-fluorapatite all appear to be well tolerated and seem acceptable for soft tissue implantation on the basis of the present data. Because of the lack of sensitivity of weight change as a parameter to measure low corrosion rates, we have no data on which to estimate the actual corrosion rate. The detailed changes in surface structurte produced during the corrosion process only provide information about the corrosion mechanism and may not be correlated with the corrosion rate. A more sensitive method to study low corrosion rates in glasses may be to use radioactive tracer techniques to measure the loss in radioactivity of glasses when implanted in the peritoneal cavity rather than subcutaneously.
    Additional Material: 20 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820060509
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  • 4
    Electronic Resource
    Electronic Resource
    In vivo evaluation of a high-strength, high-ductility stainless steel for use in surgical implants (1979)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 13 (1979), S. 543-556 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A high-strength, high-ductility, austenitic stainless steel has been evaluated for use in surgical implants by performing in vivo tests in rats, rabbits, dogs, and rhesus monkeys. This stainless steel, a TRIP (TRansformation Induced Plasticity) steel containing about 4% Mo, was compared with two alloys in current clinical use: Type 316L stainless steel and cast Vitallium. Compared with the other two alloys, cast Vitallium generally had higher resistance to corrosion and superior biocompatibility in all animals. The tests in rats and dogs indicated that the corrosion resistances of the TRIP steel and the Type 316L stainless steel were similar and that the tissue reactions caused by these alloys were also similar. However, in rhesus monkeys, the TRIP steel was shown to be susceptible to stress-corrosion cracking and much more susceptible to crevice corrosion than Type 316L stainless steel. Limited tests in rabbits supported the observation that the TRIP steel is susceptible to stress-corrosion cracking. These inconsistencies in the in vivo tests underline the need for a reevaluation of the popular test techniques and of the animals commonly chosen for assessing the suitability of candidate implant materials. The “worst case” results from the rhesus monkey tests were entirely consistent with previous results obtained from in vitro studies. However, further work must be performed before the behavior of metals in humans, rhesus monkeys, or any other animal, can be predicted with confidence from an in vitro test program.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820130403
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  • 5
    Electronic Resource
    Electronic Resource
    The effect of gamma irradiation on injectable human amnion collagen (1989)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 23 (1989), S. 833-844 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The effect of gamma irradiation on the physicochemical properties of injectable human amninon collagen was investigated. Pepsin-extracted human amnion collagen was purified, reconstituted, and irradiated with varying doses of gamma irradiation (0.25 Mrads to 2.5 Mrads). Gamma irradiation had a significant impact on the physical characteristics of the collagen. The neutral solubility of collagen in PBS at 45°C was decreased from 100% for the nonirradiated control sample to 16% for the 2.5 Mrads irradiated sample. SDS polyacrylamide gel electrophoresis also demonstrated the dose-dependent effect of gamma irradiation on collagen crosslinks. Electron microscopic observation revealed that even at low irradiation dose (0.25 Mrads), collagen fibril diameter increased. The average diameter was 50 nm for nonirradiated control fibrils, while 4.4% percent of the irradiated collagen fibrils had a diameter greater than 100 nm. Irradiated collagen showed little evidence of damage. Well-preserved cross-strations were found in collagen fibrils at all doses of irradiation. Native amnion collagen irradiated with gamma rays demonstrated a slight increase in resistance to collagenase degradation compared with nonirradiated native collagen samples. Increased resistance to collagenase did not correlate with increasing irradiation dose. After 30 min of incubation at 37°C, both irradiated and non-irradiated collagen was completely digested by collagenase. However, gamma-irradiated collagen did become more sensitive to hydrolysis by trypsin. The higher the irradiation doses used, the greater sensitivity to trypsin was observed. At 0.25 Mrads irrdiation only a slight increase was found. No marked differences in amino acid composition were noted among the high dose irradiated, low dose irradiated and control amnion collagen.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820230803
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  • 6
    Electronic Resource
    Electronic Resource
    The effects of bone cement powder on human adherent monocytes/macrophages in vitro (1993)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 27 (1993), S. 1039-1046 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: This study reports the effects of Simplex bone cement powder (BC) on the proliferation and production of bone resorbing factors in vitro by human adherent monocytes/macrophages. Adherent peripheral blood cells were isolated from seven healthy individuals and exposed to a dispersion of BC powder (1 mg/mL), phytohemagglutinin (PHA, 40 μg/mL), or medium alone at different periods of cell incubation (days 0-2, 0-7, 5-7, or 10-12). Cell proliferation was quantified by incorporation of 3H-thymidine uptake. Culture supernatants were evaluated for levels of interleukin 1-like activity (IL-1) by murine thymocyte proliferation assay, prostaglandin E2 (PGE2) by radioimmunoassay, lysosomal enzyme activity (N-acetyl-β-D-glucosaminidase and β-glucuronidase) using fluorometry, and collagen and casein degrading activity using radioactive substrates. Human adherent peripheral blood cells showed a proliferative response to PHA that coincided with cell maturation; BC did not inhibit PHA-induced cell proliferation of either adherent or nonadherent blood cells, indicating the non-toxic nature of these particles at the concentrations tested. BC stimulated increased release of the lysosomal enzyme N-acetyl-β-D-glucosaminidase; the levels of PGE2, IL-1, collagenase, and caseinase were unchanged. © 1993 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820270809
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  • 7
    Electronic Resource
    Electronic Resource
    Flow cytometric assays to detect platelet activation and aggregation in device-implanted calves (1998)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 41 (1998), S. 312-321 
    Details
    ISSN: 0021-9304
    Keywords: bovine platelets ; platelet activation ; flow cytometry ; biocompatibility assays ; ventricular-assist devices ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Cardiovascular device development often relies upon large-animal models to assess blood biocompatibility prior to initiating clinical trials. Unfortunately, the amount of information gleaned from such trials is limited by simple assays that do not take full advantage of immuno-technological advances that increasingly are applied in clinical studies. Thus we have developed and tested new flow cytometric techniques for measuring circulating activated bovine platelets and platelet microaggregates. Monoclonal antibodies (MAbs) raised against both activated and quiescent bovine platelets were incubated with control and PMA- or ADP-stimulated whole blood. Selected MAbs detected activated bovine platelets and platelet microaggregates in vitro with flow cytometry. Five calves implanted with one of two designs of nonpulsatile ventricular-assist devices (VADs) were followed with these assays prior to and during VAD implantation. Circulating activated bovine platelets and microaggregates increased after implantation in all animals and, alternatively, remained elevated or returned toward preimplant levels. Platelet activation percentages as detected temporally by three MAbs were correlated with one another, and platelet activation was correlated with microaggregate formation. In summary, these new methods for the sensitive measurement of circulating activated bovine platelets and microaggregates may provide valuable information for the development and assessment of future cardiovascular device designs. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 41, 312-321, 1998.
    Additional Material: 8 Ill.
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