title: Hypopigmentation in dogs treated with an inhibitor of platelet aggregation.
abstract: Hypopigmentation was the principal manifestation of systemic toxicity when the experimental platelet aggregation inhibitor, PD-89454, was orally administered to Beagle dogs for 28 days. Pigmentation changes were present in skin of nose, lips and eyelids and mucosa of hard palate. Fontana-Masson stain demonstrated decreased melanin within melanocytes and keratinocytes. Melanocytes were globoid with inconspicuous dendritic processes and had small, incompletely pigmented melanosomes that were quantitatively reduced relative to controls. Toxic mechanism of action of PD-89454, structurally distinct from known depigmenting compounds, was not established but ultrastructural findings suggest an interference in melanosome formation and/or melanization.
authors.affiliation: Parke-Davis Pharmaceutical Research Division, Warner-Lambert Company, Ann Arbor, Michigan 48105.
authors.forename: K M
authors.initials: KM
authors.lastname: Walsh
authors.forename: A W
authors.initials: AW
authors.lastname: Gough
mesh_terms: D000818:Animals; D001643:Bridged Bicyclo Compounds / Q000633:toxicity*; D019086:Bridged Bicyclo Compounds, Heterocyclic; D001952:Bridged-Ring Compounds / Q000633:toxicity*; D004285:Dogs; D005260:Female; D008297:Male; D008854:Microscopy, Electron; D010159:Palate / Q000473:pathology; D010859:Pigmentation Disorders / Q000139:chemically induced* / Q000473:pathology; D010975:Platelet Aggregation Inhibitors / Q000633:toxicity*; D012867:Skin / Q000473:pathology; D013844:Thiazoles / Q000633:toxicity*; D014839:Vomiting / Q000139:chemically induced
chemical_list: D001643:Bridged Bicyclo Compounds; D019086:Bridged Bicyclo Compounds, Heterocyclic; D001952:Bridged-Ring Compounds; D010975:Platelet Aggregation Inhibitors; D013844:Thiazoles; C061719:PD 89454