Radiographic features of congenital segmental dilation of the intestine in a german shepherd dog.

A 10-week-old spayed female German Shepherd Dog was presented for acute vomiting and diarrhea. There was no reported foreign body or toxin ingestion. Radiographs showed a severely (∼11 × 7 cm), focally distended right abdominal intestinal segment containing gas and soft tissue material. Other small intestinal segments were segmentally gas distended. Celiotomy identified a ∼9 cm focally dilated segment at the jejunoileal junction with no aborad luminal obstruction. Resection and anastomosis of the dilation was performed. Histopathology showed mild mucosal inflammation, but otherwise normal wall layering and autonomic ganglia. Radiographic and histopathologic findings were consistent with congenital segmental dilation of the intestine.

Acute and Protracted Cell Death in Light-Induced Retinal Degeneration in the Canine Model of Rhodopsin Autosomal Dominant Retinitis Pigmentosa.

Purpose: To characterize a light damage paradigm and establish structural and immunocytochemical measures of acute and protracted light-induced retinal degeneration in the rhodopsin (RHO) T4R dog model of RHO-autosomal dominant retinitis pigmentosa (ADRP). Methods: Retinal light damage was induced in mutant dogs with a 1-minute exposure to various light intensities (0.1-1.0 mW/cm2) delivered with a Ganzfeld stimulator, or by fundus photography. Photoreceptor cell death was assessed by TUNEL assay, and alterations in retinal layers were examined by histology and immunohistochemistry 24 hours and 2 weeks after light exposure. Detailed topographic maps were made to document changes in the outer retinal layers of all four retinal quadrants 2 weeks post exposure. Results: Twenty-four hours post light exposure, the severity of photoreceptor cell death was dose dependent. Immunohistochemical analysis revealed disruption of rod outer segments, focal loss of the RPE integrity, and an increase in expression of endothelin receptor B in Müller cells with the two highest doses of light and fundus photography. Two weeks after light exposure, persistence of photoreceptor death, thinning of the outer nuclear layer, and induction of Müller cell gliosis occurred with the highest doses of light. Conclusions: We have characterized outcome measures of acute and continuing retinal degeneration in the RHO T4R dog following light exposure. These will be used to assess the molecular mechanisms of light-induced damage and rescue strategies in this large animal model of RHO-ADRP.