title: Cerebral arteriosclerosis in an aged captive polar bear (Ursus maritimus).
abstract: Cerebral arteriosclerosis was observed upon necropsy of a 36-yr-old female captive polar bear (Ursus maritimus) that developed a sudden onset of seizure-like activity and died. The medium and large cerebral arteries of the meninges had moderate to severe diffuse discoloration and mineralization of the matrix of the tunica media, with little or no associated cellular reaction. Scanning electron microscopy of the affected arteries showed discrete crystalline calcified deposits in the media and sclerosis of the arterial wall. There were no lesions in the brainstem. The findings suggested a sudden and rapidly fatal loss of blood flow to the brain caused by long-standing arterial lesions. Incidental findings included numerous 0.1- to 10-cm-diameter, hepatic cysts lined with hyperplastic biliary epithelium, a unilateral, unipolar, 3-cm-diameter renal tubular adenoma, and approximately 250 active Baylisascaris sp. nematodes in the intestines.
authors.affiliation: Tufts University College of Veterinary Medicine, 200 Westboro Road, North Grafton, Massachusetts 01536, USA.
authors.forename: Steven
authors.initials: S
authors.lastname: McOrist
authors.forename: Flo
authors.initials: F
authors.lastname: Tseng
authors.forename: Rich
authors.initials: R
authors.lastname: Jakowski
authors.forename: John
authors.initials: J
authors.lastname: Keating
authors.forename: Chris
authors.initials: C
authors.lastname: Pearson
mesh_terms: D000375:Aging / Q000473:pathology; D000818:Animals; D000836:Animals, Zoo; D002536:Cerebral Arteries / Q000473:pathology / Q000648:ultrastructure; D003645:Death, Sudden / Q000209:etiology / Q000473:pathology / Q000662:veterinary*; D005260:Female; D002537:Intracranial Arteriosclerosis / Q000473:pathology / Q000662:veterinary*; D008855:Microscopy, Electron, Scanning / Q000662:veterinary; D001503:Ursidae