title: Measurement of in vitro P-selectin expression by flow cytometry.
abstract: Measurement of in vivo platelet activation is difficult after phlebotomy and during blood processing for analysis. We used flow cytometry to measure platelet surface expression of P-selectin in the presence and absence of trimethylsphingosine (a platelet activation inhibitor) and compared the results with those from the standard methods of preventing in vitro P-selectin expression. Percent activation was calculated as a ratio of mean sample fluorescence to 100% mean fluorescence after phorbol myristate acetate treatment. Twenty-five micromoles per liter of trimethylsphingosine kept in vitro platelet activation below 5% up to 6 hours after collection and below 10% at 24 hours after collection. Trimethylsphingosine failed to prevent platelet activation caused by centrifugation, storage at 4 degrees C, or stimulation with common agonists. Addition of trimethylsphingosine to whole blood was valuable in preventing in vitro platelet activation. This compound promises to be a useful preservative for diagnostic testing of platelet activation.
authors.affiliation: Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: S D
authors.initials: SD
authors.lastname: Kennedy
authors.forename: Y
authors.initials: Y
authors.lastname: Igarashi
authors.forename: T S
authors.initials: TS
authors.lastname: Kickler
mesh_terms: D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D002273:Carcinogens / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005434:Flow Cytometry; D006801:Humans; D019007:P-Selectin / Q000096:biosynthesis*; D015539:Platelet Activation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D013110:Sphingosine / Q000031:analogs & derivatives / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D002273:Carcinogens; D004791:Enzyme Inhibitors; D019007:P-Selectin; D010975:Platelet Aggregation Inhibitors; C071600:N,N,N-trimethylsphingosine; D011493:Protein Kinase C; D013110:Sphingosine; D013755:Tetradecanoylphorbol Acetate