Biomedical subjects
Publications and source records attributed to T Mase.
A series of 2-phenylimidazo[2,1-b]benzothiazole derivatives was prepared and tested for immunological activities. Some of the compounds showed significant suppressive activity of delayed type hypersensitivity (DTH) without inhibition of humoral immunity in mice by oral administration. The most active compound was 2-(m-hydroxyphenyl)imidazo[2,1-b]benzothiazole (20).
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The anti-platelet-activating factor effect of YM264 was examined in a variety of in vitro and in vivo test systems. YM264 inhibited [3H] platelet-activating factor binding to rabbit platelet membranes with a pKi value of 8.85. YM264 inhibited the platelet-activating factor-induced human, rabbit and guinea-pig platelet aggregation with pA2 values of 8.68, 8.33 and 8.14, respectively. However, at 10(-4) M the compound did not affect rabbit and human platelet aggregation induced by ADP, collagen arachidonic acid and epinephrine. YM264 reversed a platelet-activating factor-induced hypotension is anesthetized rats with an ED50 value of 0.005 mg/kg, i.v. Administered orally, YM264 inhibited platelet-activating factor-induced death in mice, hemoconcentration in rats and increase in vascular permeability in guinea-pigs with ED50 values of 0.19, 0.30 and 0.49 mg/kg, p.o., respectively. YM264, at 1 and 3 mg/kg, p.o., showed a significant anti-platelet-activating factor effect in a rat hemoconcentration model up to 6 hr after treatment. Moreover, in ex vivo experiments in guinea-pigs, YM264, at the doses of 0.3 to 3 mg/kg, p.o., shifted the dose-response curves of platelet-activating factor-induced platelet aggregation to the right in a parallel manner. These results indicate that YM264 is a selective, potent and orally active platelet-activating factor antagonist.