Pure-tone audiometry (audiogram)
Aug. 17, 2022
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Brains of monkeys (Macaca fascicularis, the crab-eating macaque). Histological sections were processed for GFAP immunohistochemistry. (Left) Hippocampus of a control monkey showing the granular cell layer (GL) of the dentate gyrus and the CA4 region with spaced astrocytes labeled by glial fibrillary acidic protein (GFAP) immunohistochemistry. Some immunolabeled astrocytes are clearly identified around blood vessels (arrow). Objective x10. (Right) Hippocampus of a monkey treated with a single intravenous dose of domoic acid. The initial symptoms of toxicity lasted 90 minutes and included vomiting, gagging, lethargy, and disorientation. Necropsy was conducted 6 months after the injection. Sections show marked astrocytosis as revealed by the intensity of the GFAP immunohistochemical staining seen in CA4 and the subgranular zone (arrow); granular cell layer (GL). Objective x20. (Source: Pulido 2008. Creative Commons Attribution license. http://creativecommons.org/licenses/by/3.0.)