title: Quantitation of platelet deposition on human arteries: assessment of the disparity between results obtained with 111indium (111In)-labelling versus scanning electron microscopy.
abstract: Quantitation techniques for measuring platelet deposition (PD) to vessel surfaces are important to an understanding of thrombogenesis. In previous studies, scanning electron microscopy (SEM) has been shown to indicate a lower extent of PD than platelet 111In-scintigraphy. Part of this disparity may be explained by nonspecific binding of 111In to the vessel surface during perfusion, or loss of adherent 111In-labelled platelets by lysis or dissociation from the surface during specimen preparation for SEM. To assess whether these independent processes occur, we used a previously described human placental artery (HPA) perfusion model to quantify vessel 111In retention. Of the total 111In that bound to the vessel surface during perfusion, 77 +/- 42% (N = 9) was platelet associated 111In (111In-labelled platelets) and 23 +/- 19% (N = 9) was non-platelet associated 111In (nonspecific binding). After specimen fixation, 67 +/- 32% (N = 9) of the initial total surface 111In remained. This decrease is due to dissociation of both adherent 111In-labelled platelets, and nonplatelet associated 111In. After fixation, 57 +/- 34% (N = 9) of the initial total surface 111In remained as 111In-labelled platelets and 10 +/- 13% (N = 9) remained as nonplatelet associated 111In. Fixation caused no measurable lysis of platelets. These data suggest that PD may be overestimated by 111In-scintigraphy because of nonspecific binding of 111In and underestimated by SEM because of dissociation of adherent platelets during specimen preparation for SEM.
authors.affiliation: Division of Plastic and Reconstructive Surgery, University of Pittsburgh School of Medicine, PA 15261.
authors.forename: K O
authors.initials: KO
authors.lastname: Garrett
authors.forename: M L
authors.initials: ML
authors.lastname: Bentz
authors.forename: T
authors.initials: T
authors.lastname: Macpherson
authors.forename: P C
authors.initials: PC
authors.lastname: Johnson
mesh_terms: D001158:Arteries / Q000000981:diagnostic imaging / Q000502:physiology* / Q000648:ultrastructure; D016477:Artifacts; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology*; D002448:Cell Adhesion; D005260:Female; D005404:Fixatives / Q000494:pharmacology; D006801:Humans; D007205:Indium Radioisotopes; D008855:Microscopy, Electron, Scanning; D010477:Perfusion; D010920:Placenta / Q000098:blood supply; D010976:Platelet Count; D011877:Radionuclide Imaging; D013314:Stress, Mechanical
chemical_list: D005404:Fixatives; D007205:Indium Radioisotopes