Cyclooxygenase (COX) enzymes catalyze the synthesis of prostaglandins and exist as two isoforms, COX-1 and COX-2. COX-2 is a potent inducible mediator of inflammation. COX-2 is also upregulated in several human tumors and in canine squamous cell, renal cell, and transitional cell carcinomas, prostatic adenocarcinoma, and intestinal neoplasia. The purpose of this study was to determine whether COX-2 is expressed in various feline tumors. Results of this study may help determine whether COX-2 is a potential target for therapeutic and preventive strategies in cats. Immunohistochemical studies were performed on paraffinembedded tissues using the amplified streptavidin-biotin-horseradish peroxidase system. COX-2 was found in 7 of 19 (37%) feline transitional cell carcinomas and in 2 of 21 (9%) feline oral squamous cell carcinomas. No COX-2 immunoreactivity was detected in cutaneous squamous cell carcinomas (6), adenocarcinomas (nine mammary, eight pulmonary, seven intestinal), lymphomas (six nasal, six intestinal), or 10 vaccine-associated sarcomas. The widespread absence of COX-2 expression in most feline neoplasms might suggest that COX-2 inhibitors would have a low potential as anticancer agents.

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Clinical studies indicate the potential of bronchoscopic thermal vapor ablation to result in clinically relevant improvements in severe chronic obstructive pulmonary disease patients with upper lobe-predominant emphysema. However, the mechanisms by which vapor ablation results in lung volume reduction are not fully known. This study determined the 3-month safety and efficacy of vapor ablation in a canine model of emphysema and described the histopathological changes in the lung. The cranial lobes of papain-exposed dogs were treated with a vapor dose of ten calories per gram of lung tissue (n = 8) or were sham treated (n = 3). Safety was monitored peri- and postoperatively for 3 months. Animals were then sacrificed, estimates of lung volume reduction performed, and the lungs processed for histology. Vapor ablation was associated with an average of 20% volume reduction of the treated lobes and an absence of serious adverse events. The amount of lobar volume reduction was correlated with the amount of fibrosis and atelectasis in the treated lobe. Bronchoscopic thermal vapor ablation at a dose of 10 cal/g results in lobar volume reduction associated with remodeling of the targeted tissue characterized by mature collagen formation in the absence of major adverse events.

A femoral mass from a 15-year-old rhesus macaque was evaluated. Grossly, the mass consisted of a large, osteolytic focus in the distal femur, a gelatinous core of neoplastic tissue in the medullary cavity, and an invasive mass-obliterating musculature of the thigh. On histopathologic evaluation, three neoplastic mesenchymal cell populations, osteoblasts, fibroblasts, and primitive mesenchymal cells were identified. The mass was diagnosed as a combined type osteosarcoma. To our knowledge, this is the first osteosarcoma in a rhesus macaque with this subclassification.