ABSTRACT
Amphiphilic coupling-polymer of stearyl poly (ethylene oxide)-co-4, 4'-methylendiphenyl diisocyanate-co-stearyl poly(ethylene oxide), MSPEO, was specially designed as surface-modifying additives. The blends of MSPEO in both polyether urethane (PEU) and chitosan(Chi), as the coating materials for intravascular device were investigated. Two kinds of static clotting time tests, plasma recalcification time (PRT) and prothrombin time(PT), as well as the static platelet adhesion experiment were carried out. And the dynamic anti-coagulation experiment was performed with a closed-loop tubular system under a blood shear rate of 1,500 s-1. The results demonstrate that both blend coatings can improve the anti-coagulation of polyurethane greatly and will not lead to hemolysis, and that more platelets adhere to the surface modified by Chi-MSPEO blend coating as compared with those adhere to the surface modified by PEU-MSPEO blend coating. The surface modified by Chi-MSPEO has longer PRT, whereas the surface modified by PEU-MSPEO has longer PT.
Subject(s)
Humans , Blood Coagulation Tests , Chitin , Chemistry , Chitosan , Coated Materials, Biocompatible , Chemistry , Ethylene Oxide , Chemistry , Materials Testing , Platelet Adhesiveness , Polymers , Chemistry , Polyurethanes , Chemistry , Prothrombin Time , Surface PropertiesABSTRACT
Human gastric cancer cells (MKN-45) were transfected with pULB3238 (a plasmid carrying MVMp NS gene). After the NS gene expressed, some of the NS-transfectants were died. The other cells were survived. In comparison with those of control MKN-45, the survived NS- transfected MKN-45 cells had the following characterizations: (a). nucleus/cytoplasm ratio reduced; (b). generation time prolonged;(c). adhesion ability between cells increased;(d). cloning efficiency decreased;(e). formation of tumors in nude mice suppressed. To investigate the possible mechanisms of above mentioned change of NS-transfectants, the effect of NS on the expression of some cytokine genes were explored. RNA dot blot indicated that the NS might enhance the expression of IL-l?(2.7 times), IL-1/?(4.6 times) IL- 6 nuclear factor (2.5 times) and had no effect on the expression of IL-6. The results suggested that the antineoplastic activity of parvoviruses may be medicated by NS interfere with the expression of cytokines in the host cells.