Primary peri-aortic hemangiosarcoma in a dog.

A 10-year-old intact male Norwich terrier dog was evaluated for progressive, intermittent increased respiratory effort. Thoracic radiographs, ultrasonography, and computed tomography were used to identify a caudodorsal thoracic extrapulmonary mass and the presence of pulmonary metastasis. Blood transfusion and stabilization measures were not successful and the patient died. Necropsy confirmed the origin of the mass to be the adventitial layer of the aorta and determined it to be hemangiosarcoma. This is a rare site for the primary lesion.

Hémangiosarcome péri-aortique primaire chez un chien. Un chien Norwich terrier mâle intact âgé de 10 ans a été évalué pour effort respiratoire intermittent accru progressif. Des radiographies thoraciques, une échographie et une tomodensitométrie ont été utilisées pour identifier une masse extrapulmonaire thoracique caudodorsale et la présence de métastases pulmonaires. Une transfusion de sang et des mesures de stabilisation n'ont pas eu de succès et le patient est mort. La nécropsie a confirmé l'origine de la masse comme étant la couche adventice de l'aorte et a déterminé qu'il s'agissait d'un hémangiosarcome. Il s'agit d' un site rare pour une lésion primaire.(Traduit par Isabelle Vallières).

Increased susceptibility to urethane-induced lung tumors in mice with decreased expression of connexin43.

Gap junction intercellular communication capacity and connexin expression are reportedly decreased in human lung cancer. The mechanisms by which connexins, the gap junction proteins, act as tumor suppressors are unclear. In order to understand the involvement of connexins in tumorigenesis, we analyzed the effect of the heterologous deletion of Gja1 [the connexin43 (Cx43) gene] on the development of lung adenomas in mice. Heterozygous (Cx43(+/-)) and wild-type mice (Cx43(+/+)) were treated or not with single doses of urethane at 15 and 17 days after birth. Twenty-five weeks later, both the number and size of nodules were increased in Cx43(+/-) mice as compared with Cx43(+/+) mice. Moreover, the lesions were histologically more aggressive in the heterozygous mice. However, no increase in spontaneous lesions was observed in the lungs of untreated Cx43(+/-) mice. Heterozygous mice effectively presented lower expression of Cx43 genes and decreased amounts of Cx43. In conclusion, our results indicate that deletion of one allele of the Cx43 gene clearly favors the carcinogenic effect of urethane administration and results in a higher susceptibility to lung adenoma formation in mice.