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Biomedical subjects

N Yui

Publications and source records attributed to N Yui.

112 records · Page 7Linked to original sources

Effect of biodegradable polyrotaxanes on platelet activation.

Cellular response to our designed biodegradable polyrotaxanes was evaluated in terms of physicochemical interaction with plasma membrane and intracellular metabolism of platelets. The polyrotaxanes, in which many hydroxypropylated (HP-) alpha-cyclodextrins are threaded onto a poly(ethylene glycol) chain capped with a L-phenylalanine moiety via a peptide linkage, were synthesized and characterized. The polyrotaxanes inhibited cytoplasmic calcium increase in platelets, increased plasma membrane fluidity of red blood cell ghosts, and elevated cytoplasmic cyclic-3',5'-AMP levels in platelets. Such cellular response to the polyrotaxanes was observed, which was more than that to constituent molecules. These results suggest that the supramolecular structure of the polyrotaxanes contributes to acceleration of the physicochemical interaction with plasma membrane and intracellular metabolism of platelets. Thus, biodegradable polyrotaxanes can be useful as new biomaterials for fabricating blood-contacting devices.

Animals↗

A new blood compatible and permselective hollow fiber membrane for hemodialysis.

The authors have prepared a blood compatible and highly permselective hemodialysis membrane composed of polyether segmented nylon. This block copolymer was synthesized by polycondensation of bis-3-aminopropyl-poly(tetramethylene oxide) (PTMO) and poly(imino-1,3-bismethyl-cyclohexyl-iminoisophtharoyl) (NyBl) prepolymer obtained by polycondensation of 1,3-bis(aminomethyl)cyclohexane (B) and isophthalic acid (I). The molecular weight (MW) calculated from the number of end-groups was 16,000-21,000. In vitro blood compatibility was evaluated in terms of platelet adhesion onto the surface. PTMO-NyBl surfaces showed excellent platelet adhesion preventing properties. The PTMO-NyBl hollow fiber membrane was obtained by a dry-wet spinning process. The membranes had higher permeability coefficients for macromolecules ranging from MW 10,000 to 20,000 than polysulfone hollow fiber membrane (PS membrane), and had acceptably low albumin permeability for use as a dialysis membrane. The ex vivo blood compatibilities of PTMO-NyBl membrane and PS membrane were investigated by extracorporeal circulation in a pig model. The PTMO-NyBl membrane gave excellent results when assessing hemodialysis leukopenia, oxidative burst, and free platelet count decrease.

Biocompatible Materials↗