Congenital cardiac disease in dogs

Pulmonic stenosis is caused by a malformed pulmonic valve, stricture of the right ventricular outflow tract or stricture of the pulmonary artery. English Bulldogs, Beagles, Samoyeds, Fox Terriers and Chihuahuas are predisposed. Clinical signs in severely affected dogs include exercise intolerance, stunting, dyspnea, syncope and ascites. Auscultation reveals a high-frequency, crescendo-decrescendo murmur during systole, loudest over the left side of the thorax, near the sternal cardiac border. An ECG may reveal a right-axis deviation of greater than 120 degrees, S waves in leads I, II and III, deep S waves in CV6LL, CV6LU and V10, Q waves deeper than 0.5 mv in leads II, III and AVF, and positive T waves in lead V10. Plain film LAT thoracic radiographs reveal an elevated carina, increased sternal contact of the heart, loss of the cranial cardiac waist and a widened cardiac silhouette, with normal pulmonary vasculature. A DV projection reveals an inverted "D" shape of the right ventricle and a pulmonary artery bulge. A nonselective angiocardiogram reveals poststenotic dilation of the main pulmonary artery. Treatment involves surgical correction of the stenosis.     

Retroperitoneal fibrosis in four cats following renal transplantation

Four cats developed fibrosis within the retroperitoneal space following renal transplantation. In human transplant patients, retroperitoneal fibrosis is an uncommon complication following surgery and may be secondary to operative trauma, infection, deposition of foreign material in the operative field, urinary extravasation, and perirenal hemorrhage caused by trauma to the allograft. Possible causes of fibrosis in the cats of this report include abdominal inflammation associated with allograft rejection, pyelonephritis, and septic peritoneal effusion. All of the cats of this report were readmitted to the veterinary teaching hospital following renal transplantation because of recurrence of azotemia 1 to 5 months after transplantation. Abdominal ultrasonography revealed a 2- to 4-mm-thick capsule surrounding the allograft in 2 of 4 cats, hydronephrosis in 4 cats, and hydroureter proximally in 2 cats. An exploratory laparotomy was performed in all cats to remove the fibrotic tissue causing the ureteral obstruction. Normal renal function was restored in all cats following surgery. Histologic evaluation of biopsy specimens revealed smooth muscle (3 cats) and fibrous connective tissue (4). All 4 cats, regardless of the cause, responded well to surgical resection of the scar tissue that was causing a ureteral obstruction. None of the cats had recurrence of obstruction following surgery.     

Contagious ecthyma in the live sheep export industry

Objective: To investigate control options for contagious ecthyma (scabby mouth) in Australian sheep exported live to the Middle East.
Design: Prevalence, vaccination and modelling studies.
Procedure: One hundred and forty weaner sheep (less than 1 year old) on each of 106 farms in Western Australia (WA) and 18 farm groups of adult wethers received at a WA commercial feedlot were examined for lesions of scabby mouth. Sheep on a total of 26 farms in 3 States were divided into treatment and control groups for the vaccination study. A simple deterministic compartmental model was developed to establish which parameters had the greater effect on disease prevalence.
Results: The proportion of farms with evidence of scabby mouth in weaner sheep was 23.6% and, on those farms with the disease, the overall prevalence was 6.1%. At the feedlot, 4 out of 18 farm groups had 5 or more sheep with lesions on arrival. The overall prevalence in the 4 diseased groups was 5.2%. Sheep vaccinated on farm before trucking to the feed-lot had a lower prevalence of scabby mouth at the end of simulated shipping than controls. The main determinant of scabby mouth prevalence was the proportion of sheep immune to the disease.
Conclusion: A program of vaccination for scabby mouth will reduce the prevalence of disease during live export. However, using current technology it is not possible to deliver shipments of sheep to the Middle East that are guaranteed completely free of scabby mouth.     

Hypercalcemia following renal transplantation in a cat

An 11-year-old 3.0-kg (6.6-lb) neutered male Persian was referred for renal transplantation. Serum total calcium concentration was slightly high prior to surgery, but the week after surgery, total and ionized calcium concentrations were extremely high, and a small mass was palpable on the right side of the trachea at the level of the thyroid and parathyroid glands. Exploratory surgery of the ventral aspect of the neck was performed, and a right external parathyroid mass was removed. One hour after surgery, the serum ionized calcium concentration was within reference limits, and the serum calcium concentration remained normal for the next 14 months without any specific treatment. The gross and histologic appearance of the mass, combined with the rapid decrease in serum calcium concentration following its removal, confirmed that the mass was a functional parathyroid adenoma. Although a common postoperative complication in people, hypercalcemia following renal transplantation appears to be a rare complication in cats. Surgery should be considered if the condition is a result of a parathyroid adenoma.     

Hepatic microvascular dysplasia in dogs: a retrospective study of 24 cases (1987-1995)

Hepatic microvascular dysplasia (HMD) is a disease involving a microscopic shunting of blood through the liver without the presence of a macroscopic portosystemic shunt (PSS). Data was collected from medical records and telephone conversations with referring veterinarians and owners of 24 dogs diagnosed with HMD. Criteria for diagnosis included histopathological evidence of microvascular dysplasia on hepatic biopsy as well as surgical exploration and a normal mesenteric portogram to rule out a macroscopic PSS. Dogs with HMD frequently have less severe clinical signs and a better long-term prognosis than do those with a PSS that are managed medically.     

Unguided bronchoalveolar lavage techniques and residual effects in dogs

Objectives To investigate the use of unguided bronchoalveolar lavage techniques in dogs without fibreoptic bronchoscopy, using an adapted single vascular catheter and a double-lumen catheter made from two single vascular catheters.
Animals Sixty-nine dogs were examined with the single-catheter technique and 110 dogs with the double-catheter technique.
Design A prospective study.
Procedure Sixty-nine and 220 samples, collected with the single catheter and the double catheter respectively, were examined cytologically Lungs of 69 dogs were examined grossly and histologically. Radiographic examination was performed on 11 dogs.
Results The double-catheter technique produced samples with significantly higher cellularity (P < 0.01) and fewer red blood cells (P < 0.01) than the single-catheter technique. Repeat samples collected with a double catheter were not significantly different (P > 0.01) in any value. A reference range for nucleated cell counts of 62 to 1210 – 10⁶/L was calculated from 57 clinically and histologically normal dogs. The major residual effects of the technique were localised pulmonary oedema, and alveolar distension with collapse and congestion of distant parenchyma. Thoracic radiographs revealed increased lung opacity for at least up to 7 h after the procedure.
Conclusions The cellularity of the bronchoalveolar lavage fluid obtained was adequate and sufficient fluid was retrieved when the single catheter was located in a proper position. However, the double catheter obtained better samples more quickly and easily, with less damage to the respiratory tract.     

The neural basis of economic decision-making in the Ultimatum Game

The nascent field of neuroeconomics seeks to ground economic decision making in the biological substrate of the brain. We used functional magnetic resonance imaging of Ultimatum Game players to investigate neural substrates of cognitive and emotional processes involved in economic decision-making. In this game, two players split a sum of money;one player proposes a division and the other can accept or reject this. We scanned players as they responded to fair and unfair proposals. Unfair offers elicited activity in brain areas related to both emotion (anterior insula) and cognition (dorsolateral prefrontal cortex). Further, significantly heightened activity in anterior insula for rejected unfair offers suggests an important role for emotions in decision-making.