ABCB1 and scrapie: In vitro anti-prion activities of quinacrine and compounds 37–39 on murine neuroblastoma cells infected mouse adapted scrapie strains (ScN2a and N167) and a human prion strain (F3), binding responses of test compounds to hPrP121–231 by SPR, permeability by PAMPA-BBB assay, log D and efflux ratio across wild type MDCK-MDR1 cell monolayers.