Unusual bilateral ureter strangulation by fibrous tissue after perineal hernia repair in a dog.

A 10-year-old castrated male cross-breed dog was referred for the repair of perineal hernia with bladder retroflexion and a mass lesion in the hernial sac. Surgical treatment was performed and the mass was identified as degenerated adipose tissue that was suspected to be derived from the omentum. The hernial contents were reduced without difficulty, and the dog exhibited a normal recovery. Two days after surgery, the dog suddenly exhibited anorexia and azotemia. Exploratory laparotomy was performed, which showed the dilation of both ureters with discoloration of the bladder serosa and strangulation of the urinary bladder neck. Careful inspection confirmed that a fibrous band, which was connected to the mass-like degenerated adipose tissue, had caused the strangulation. Two days after removal of these tissues, the dog recovered, with normal findings on blood biochemical analysis. The condition described in this report is an uncommon complication of perineal hernia repair. The findings suggest that degenerative fat tissue should be resected during perineal hernia repair in dogs, in order to prevent possible bladder strangulation after surgery.

Differences in respiratory changes and Fos expression in the ventrolateral medulla of rats exposed to hypoxia, hypercapnia, and hypercapnic hypoxia.

Respiratory responses to hypoxia and/or hypercapnia, and their relationship to neural activity in the ventrolateral medulla (VLM), which includes the respiratory center, have not yet been elucidated in detail. We herein examined respiratory responses during exposure of 10% O2 (hypoxia), 10% CO2 (hypercapnia), and 10% O2-10% CO2 (hypercapnic hypoxia) using plethysmography. In addition to recording respiration, Fos expressions were examined in the VLM of the rat exposed to each gas to analyze neural activity. Respiratory frequency was increased in rats exposed to hypoxia, and Fos-positive neurons were observed in the caudal VLM (cVLM) and medial VLM (mVLM). Tidal volume was increased in rats exposed to hypercapnia, and Fos-positive neurons were observed in the rostral VLM (rVLM) includes the retrotrapezoid nucleus (RTN) and mVLM. Tidal volume was enhanced in rats exposed to hypercapnic hypoxia, similar to that in hypercapnia-exposed rats, and Fos-positive neurons were observed in the entire region of the VLM. In the mVLM and cVLM, double immunofluorescence showed Fos-immunoreactive nerve cells were also immunoreactive to dopamine ß-hydroxylase, the marker for A1/C1 catecholaminergic neuron. These results suggested that hypoxia and hypercapnia modulated rhythmogenic microcircuits in the mVLM via A1/C1 neurons and the RTN, respectively.