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  • 1
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Inhibition of cultured mammalian cell growth was used to examine the biological activity of triethyl citrate, a common plasticizer for poly(vinyl chloride). Cell populations were determined by a sample extraction procedure and measurement of nucleic acid content (total purines and pyrimidines) by its absorbance at 268 mm̈. Triethyl citrate demonstrated strikingly different dose-effect characteristics from its theoretical hydrolysis products (ethanol and citric acid). The inhibitory effects of sodium citrate were reversed by calcium chloride while the action of triethyl citrate underwent little or no change under similar conditions. Triethyl citrate did not appear to produce resistant cell strains in culture but did seem to be degraded with time. Inhibitory action of triethyl citrate was shown to be independent of inoculum size within the ranges utilized in the study. The procedures described appear to have a number of advantages for the biological or toxicological evaluation of ingredients which might be added to a plastic formulation or to contaminates which might enter the plastic during manufacture of the item or device.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 17 (1983), S. 945-957 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Quantitative hemolysis assays of acrylate and methacrylate esters provided estimates of the intrinsic hemolytic activity (Hi the slope of the concentration-response curve) and the concentrations effecting 5% (H5) and 50% (H50) hemolysis. The dependence of hemolytic activity and LD50 (mice) on physical properties (lipophilicity, molar refraction, and molecular volume) of the esters was determined by multiple regression analysis. The observed correlations were: Hi, R2 = 0.94; H5, R2 = 0.95; H50, R2 = 0.94; and LD50, R2 (all compounds) = 0.80, R2 (all compounds less the methyl esters) = 0.94. The difference of the methyl esters was associated with the smaller steric volume of the methyl ester substituent and the presence (methacrylates) or absence (acrylates) of the branched methyl group. Associative steric contributions of the branched methyl group and the ester substituents were probably responsible for greater variability in the methyacrylate series. The results were consistent with the conclusion that the mechanism of the action of the esters is membrane mediated and relatively nonspecific and that in vivo biotransformation was not a significant factor. Also, long-term toxic liability of the esters may be more closely related to intrinsic toxicity than acute toxicity.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A broad dental toxicology screening program has been initiated to develop suitable testing methods for new dental materials or products which presently are not considered as drugs. In the report presented here, 42 materials or products have been included in an acute toxicity screening program for the evaluation of irritancy properties. Depending upon the state of the material or product, one or more testing procedures were employed. These included: (1) implantation in rabbit muscle, (2) a tissue culture test, (3) an intradermal test in rabbits, (4) an eye test in rabbits, and (5) a dermal test in rabbits. With the limited number of materials or products, the most suitable method of testing solids was the implantation method and tissue culture. Tissue culture appeared to be the only useful method for powders while tissue culture and an intradermal test the most suitable method for liquids. Other materials and products will be included using these test procedures to note if one or two might eventually be selected as a preferred method of “irritancy” testing when a large number of materials or products are to be screened for a dental or medical application. The final evaluation of safety for a dental material or product must of course be based upon its intended use.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 3 (1969), S. 291-303 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A tissue culture test and a 7 day implantation method in rabbits were used to screen the toxic potential of 50 tubings used in one or more medical or paramedical applications. Results of the tests revealed that approximately 32% of the tubings contained one or more ingredients which, when released to cells or tissue, caused a toxic response. A similar study six years previously showed that 52% of the tubings tested had toxic potential. It is apparent that improvements have been made in the medical tubings (from point of view of safety), but steps must still be taken to reduce the potential risk to levels approaching zero.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 9 (1975), S. 569-596 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A series of poly(methyl methacrylate) formulations differing widely in chemical and physical properties was employed for the evaluation of primary screening methods for the assessment of acute toxicity. Materials and USP extracts of materials were tested in parallel. Tissue culture, hemolysis, intradermal irritation, systemic toxicity, muscle implant and histopathologic responses were determined for each of 27 formulations. A determination of the nonvolatile methanol extractable components was carried out on each formulation. The formulations varied with respect to percent, w/w, methyl methacrylate, N,N-dimethyl-p-toluidine, stannous octoate, 3,4-diamino-toluene and, also, with respect to curing conditions. Volatile components, primarily methyl methacrylate, of three selected formulations were determined quantitatively by vacuum distillation and mass spectrographic analysis.Statistical analysis of the primary data indicated a significant correlation of residue weight (methanol extractable) with hemolytic activity (r = 0.93) and with the cumulative biological response (r = 0.9). Multiple linear regression analysis of residue weights with hemolysis and intradermal irriation responses gave the highest overall correlation (r = 0.96). Hemolytic activity and tissue culture responses were significantly correlated (r = 0.87). It was concluded that the observed variation of biological test results reflected significant differences in the toxicity of the test materials. The poly(methyl methacrylate) series examined was relatively low in toxicity and the biological tests examined, particularly the in vitro tests, were found to be responsive to formulation and curing conditions which indicated their suitability for primary toxicity screening.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968), S. 181-181 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A group of 12 materials was evaluated for tissue compatibility via a sequential histopathologic evaluation of the rabit muscle response to the implanted materials. Tissue samples were obtained daily for 7 days and weekly for 12 weeks to follow the time course of the response. Some cytotoxic samples revealed a rapid and marked response of relatively short duration, whereas others tended to produce a sustained or a long-term, intermittent inflammatory and/or necrotic response. These effects also demonstrated the suitability of 7 days as a satisfactory time period for routine evaluation of rabbit muscle reaction to implanted materials. The histopathologic evaluation of the response was compared with a gross evaluation of the implant site and an independent test of the material by tissue culture (agar-overlay method).
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 8 (1974), S. 11-34 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A series of systemic toxicity tests for various types of compounds are presented with illustrative data and discussed in regard to their relevance as potential screening tests for dental compounds and products. In developing and marketing a new dental material, it is important not only to ensure safety for the patient but also for the dentist, dental assistant, and laboratory worker who routinely handles and uses the product. Data are presented on a number of commercially available dental products as well as various chemical entities, which were tested by one or more of the methods described.
    Additional Material: 11 Tab.
    Type of Medium: Electronic Resource
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