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Biomedical subjects

D J Lyman

Publications and source records attributed to D J Lyman.

At least 37 records · Page 2Linked to original sources
PubMed1977

Block copolyurethanes in the urinary system.

Free floating segments of block copolyurethane were implanted into rat bladders and compared with similar implants of silicone rubber. This urethane was far superior to silicone rubber in its ability to withstand incrustation in the rat bladder. Ten dogs had a segment of right ureter replaced by a tubular segment of smooth (or film) urethane and were followed with intravenous urography. At 1 month, eight of 10 dogs had right hydronephrosis. At the time of sacrifice (4 or 8 months) seven dogs had reduced hydronephrosis, and in three dogs intravenous urography was unsatisfactory for grading. Only two of the ten dogs had significant urinary infection. A smooth protein-like coasting appeared along the lumen of the graft, incrustation was minimal, and new mucosa and smooth muscle regeneration was seen. This material was well tolerated in the urinary tracts of dogs and rats.

Animals↗
PubMed1975

Polymers in contact with the body.

The clinical use of polymeric materials in the body to repair and restore damaged or diseased tissues and organs is substantially increasing on an annual basis. Concomitant with this use is an increase in materials related research on medically used polymers. Information on the historical and current clinical use of polymeric materials is provided in order to establish a basis for the philosophy and problems encountered in assessing the acceptability of various polymers in the biological system. The requisite properties which must be demonstrated by a polymer in contact with the body are discussed from two viewpoints, i.e., the effects of the material on the stability of the host and the effects of the host on the stability of the material. In addition, the effects of synthesis, processing, storage, sterilization, implantation, and possible degradation of polymers are discussed, poly(ethylene terephthalate) being used as an example.

Biomedical Engineering↗
PubMed1975

The effects of chemical structure and surface properties of synthetic polymers on the coagulation of blood. IV. The relation between polymer morphology and protein adsorption.

Although these studies are preliminary, they do not show that the chemical structure of the block copolymer is not the only determinant of its blood properties; one must be equally concerned with the effect of its domain-matrix size and purity. These features, which are affected by factors such as block size, mold surface, and general fabrication procedures, as well as chemical structure, must be controlled if one is to have reproducible results in the function of an implant.

Adsorption↗