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  • 1
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 7 (1973), S. 111-121 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The biological tolerance of poly(N-substituted acrylamides) implanted subcutaneously to rats and pigs was investigated. Besides a macro- and microscopical evaluation of the implant and its surroundings, the surface changes of the implants were determined by means of a Stereoscan electron-optical microscope;the results obtained confirmed the very good in vivo stability of the polymers used.The histological analysis showed that all the polymers under investigation are very well tolerated by the organism and do not provoke any unfavorable reaction. The implants become surrounded with a granulation tissue which is gradually replaced by fibrocytes and collagen fibers situated in the basic substance staining positively with the alcian blue and PAS. In contrast with some authors we did not find a thicker capsule surrounding the implant on the sharp edges but on the flat planes. No calcification could be observed within the intervals investigated. The surface changes, which were studied electronoptically, were insignificant and connected with the way in which the implant was treated. No indications of malignant growth were observed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 7 (1973), S. 123-136 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The long-term biological tolerance of hydrophilic gels containing ionogenic groups was investigated on animals (rats and pigs). The basic polymeric skeletons of poly(glyco1 monomethacrylate) and poly (N-ethyl methacrylamide) were modified by introducing acidic (carboxylic) and basic (tert-amino) groups, or both groups at a time. Introduction of both groups at a time in the molar ratio yielded an electroneutral polymer of ionogenic character.In all groups investigated here the implant was encapsulated by a fine capsule of collagen fibrous tissue; no signs of proliferation were observed. No calcification took place.The second part of the work consisted in an investigation of the tolerance of heterogeneous poly(glyco1 monomethacrylate) gels containing ionogenic groups,basic, acidic, and ampholytic, with continuously changing porosity. The microporous polymers (50-60% water in the starting mixture) were healed-in as compact gels by encapsulation with collagen fibrous tissue. The macroporous polymers (70% of water and more in the starting mixture) were encapsulated with a capsule of collagen fibrous tissue, from which newly formed capillaries,serous exudate and numerous cells penetrated into the implant. The more porous the material, the broader the zone of cellulization. In microporous polymers there was no calcification; in macroporous, calcification occurred in the margin of the implant or in its center. In contrast with other authors' findings,no effect of the chemical composition within the concentration range investigated upon the way of healing-in or calcification could be observed; only the effect of physical factors was evident.
    Additional Material: 5 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 5 (1971), S. 197-205 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Experiments were investigated on animals' biological tolerance of the copolymers of N-substituted methacrylamides with the monomers which can be considered for uses in the modification of the monomeric backbone. The group of N-substituted methacrylamides is the second one in the series of hydrophilic polymers arranged according to their increasing resistance to hydrolysis, and it follows immediately after the esters of methacrylic acid. Histological analysis has shown that the copolymer of N-ethyl methacrylamide with methyl methacrylate is the best tolerated polymer of this group. In the case of copolymers with butyl acrylate and butyl methacrylate, in the first days after implantation a stronger and more cellular capsula was formed, and an inflammation was observed in the surroundings of the encapsulated implant. Starting from day 30, however, no differences are found in the encapsulation, and the result of healingin of all the polymers is always favorable. No cancerogenic effects were observed; calcification was found only sporadically in the case of the copolymer with butyl methacrylate.
    Additional Material: 6 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 5 (1971), S. 225-238 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Investigation has been made of the short-term tolerance of hydrophilic polymers on the basis of poly(hydroxy ethyl methacrylates) containing various amounts of acidic and basic groups. The worst tolerance was found with gels containing basic groups alone.
    Additional Material: 8 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 9 (1971), S. 2801-2815 
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The present paper deals with the transport properties of membranes made of hydrophilic gels containing ionogenic groups. Introduction of ionogenic groups into a gel based on 2-hydroxyethyl methacrylate will affect the permeability of the investigated membranes for sodium chloride by an order or more. Dependences of the permeability on the content of ionogenic groups, three-dimensional network density, and pH were established. The permeability for NaCl was compared for that for bivalent salt (MgSO4). It is shown, on the basis of independently determined distribution coefficients, that an increase in the permeability of ampholytic membranes in comparison with the neutral ones is primarily due to an increase in the diffusivity of the salt in the membranes with modified structure. It can also be concluded that an approximation of the free volume from the volume of the solvent in the membrane cannot be applied to the poly(2-hydroxyethyl methacrylate) gel.
    Additional Material: 10 Ill.
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  • 6
    Publication Date: 1970-01-01
    Print ISSN: 0021-9673
    Electronic ISSN: 1873-3778
    Topics: Chemistry and Pharmacology
    Published by Elsevier
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  • 7
    Publication Date: 1974-04-01
    Print ISSN: 0021-9673
    Electronic ISSN: 1873-3778
    Topics: Chemistry and Pharmacology
    Published by Elsevier
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