Vacuolar myopathy in a dog resembling human sporadic inclusion body myositis

Sporadic inclusion body myositis (sIBM) is the most common myopathy in people over the age of 50 years. While immune-mediated inflammatory myopathies are well documented in dogs, sIBM has not been described. An 11-year-old dog with chronic and progressive neuromuscular dysfunction was evaluated for evidence of sIBM using current pathologic, immunohistochemical and electron microscopic diagnostic criteria. Vacuoles and congophilic intracellular inclusions were identified in cryostat sections of multiple muscle biopsies and immunostained with antibodies against amyloid-β peptide, amyloid-β precursor protein, and proteosome 20S of the ubiquitin–proteosome system. Cellular infiltration and increased expression of MHC Class I antigen were observed. Cytoplasmic filamentous inclusions, membranous structures, and myeloid bodies were identified ultrastructurally. These observations constitute the first evidence that both the inflammatory and degenerative features of human sIBM can occur in a non-human species

Persistent papillomavirus infection in a cat

A seven-year-old, neutered male, crossbred Persian was diagnosed as having persistent, cutaneous papillomavirus infection. The skin lesions consisted of round, multifocal-to-confluent, raised, black plaques on the neck, thorax, shoulders, and forelegs. Papillomavirus virions were demonstrated in negative-stained, electron microscopic preparations of homogenized skin lesions and within the nuclei of cells from the stratum granulosum. Avidin-biotin immunoperoxidase stains were positive for papillomavirus in the same cells. The cat was euthanized due to a clinical diagnosis o concurrent, severe, chronic pancreatitis.</jats:p