title: Glycoprotein Ib bioassays. Activity levels in Bernard-Soulier syndrome and in stored blood bank platelets.
abstract: Glycoprotein Ib (GP-Ib) is a major platelet receptor protein concerned with von Willebrand-factor binding, platelet agglutination, and platelet adhesion, and it is required for normal hemostasis. By the use of botrocetin (venom coagglutinin), both quantitative and semiquantitative assays for GP-Ib activity were developed. The latter assay uses limiting dilutions of botrocetin as a measure of GP-Ib activity. Platelets, stored up to 23 days under blood bank conditions, were assayed by the limiting dilution test. Values of GP-Ib were progressively diminished after 9 to 10 days of storage, reaching levels of less than 10% at 23 days. Platelets from a subject with Bernard-Soulier syndrome showed less than 10% GP-Ib activity. These assays appear to be a specific measure of functional GP-Ib activity, and, when combined with GP-Ib antigen measurement by other methods, they provide a means for further characterizing GP-Ib abnormalities.
authors.affiliation: Department of Pathology, University of North Carolina, Chapel Hill 27599.
authors.forename: L A
authors.initials: LA
authors.lastname: Eaton
authors.forename: M S
authors.initials: MS
authors.lastname: Read
authors.forename: K M
authors.initials: KM
authors.lastname: Brinkhous
mesh_terms: D001606:Bernard-Soulier Syndrome / Q000097:blood*; D001771:Blood Banks; D001792:Blood Platelets / Q000378:metabolism*; D001793:Blood Preservation; D003435:Crotalid Venoms; D006388:Hemagglutinins; D006801:Humans; D007201:Indicator Dilution Techniques; D010980:Platelet Membrane Glycoproteins / Q000032:analysis*; D013997:Time Factors
chemical_list: D003435:Crotalid Venoms; D006388:Hemagglutinins; D010980:Platelet Membrane Glycoproteins; C030961:botrocetin