Macroscopic and microvascular blood supply of the canine common calcaneal tendon.

Chronic tendinopathy injuries to the canine common calcaneal tendon are relatively common in large breed dogs and typically affect the distal portion of the tendon. In humans, poor blood supply, biomechanical faults, poor training methods and fluoroquinolone administration have all been linked with the development of Achilles tendinopathy. The most common sites for Achilles tendinopathy in humans seem to correspond with areas of poor blood supply within the tendon. The aim of this study was to evaluate the blood supply of the canine common calcaneal (Achilles) tendon to determine if variations occur along the tendon. The null hypothesis was that there would be no difference in the microvascular blood supply at varying points along the tendon. Paired pelvic limbs were collected from 12 large breed dog cadavers. A 50% barium sulphate and 50% saline solution was infused into the femoral artery of one limb from each dog and radiographs were taken to outline the blood supply to the common calcaneal tendon. Indian ink was infused into the contralateral limb. The common calcaneal tendon was removed, fixed and sectioned at 1 cm intervals, from calcaneal insertion to musculotendinous junction. The ink-filled arteries and arterioles in each section were counted. Radiographs revealed fine branches from the caudal saphenous artery entering the mid-body of the tendon along its cranial border. The musculotendinous junction had additional branches from the gastrocnemius muscles. Distally, vessels radiated proximally from the calcaneus 2 to 3 cm into the tendon. Mean total vessel counts at the insertion (138.54 +/- SD 31.06) were significantly higher than all other sections (p <0.001). The mid-body had significantly lower total vessel counts. When the cross sectional area of the tendon was taken into account, only the insertion had a significantly higher mean vessel count/cm2 than the mid-body of the tendon. There were no other significant differences in mean vessel count/cm2. Areas of poorer blood supply did not correspond with the most commonly reported site for chronic common calcanean tendinopathies, suggesting that inherent poor blood supply at the site of injury may not play a role in the pathogenesis. Atraumatic handling and minimal manipulation should be used during the surgical approach and debridement to preserve the remaining blood supply in ruptured tendons.

Prospective evaluation of laparoscopic pancreatic biopsies in 11 healthy cats.

BACKGROUND: Definitive diagnosis of feline pancreatic disease is dependent on histologic examination of biopsies. HYPOTHESIS: Laparoscopic punch biopsy of the pancreas does not significantly affect pancreatic health or clinical status of healthy cats, and provides an adequate biopsy sample for histopathology. ANIMALS: Eleven healthy female domestic shorthair cats. METHODS: Effects of laparoscopic pancreatic visualization alone in 5 cats compared with laparoscopic pancreatic visualization and punch biopsy in 6 cats were studied. Temperature, pulse, and respiratory rate, physical examination, and daily caloric intake were evaluated for 1 week before and 1 week after the procedure. Pain scores (simple descriptive score and dynamic interactive visual assessment score) were evaluated hourly during the 1st 6 hours postprocedure. Complete blood cell counts, serum biochemical profiles, serum feline pancreatic lipase immunoreactivity, and urine specific gravity were evaluated before the procedure and at 6, 24, and 72 hours postprocedure. One month postprocedure, during sterilization, the pancreas was reassessed visually in all cats, and microscopically in the biopsy group. RESULTS: For all variables evaluated, there were no significant differences between biopsy and control cats. Re-evaluation of the pancreatic biopsy site 1 month later documented a normal tissue response to biopsy. The laparoscopic punch biopsy forceps provided high-quality pancreatic biopsy samples with an average size of 5 mm x 4 mm on 2-dimensional cut section. CONCLUSIONS AND CLINICAL IMPORTANCE: Laparoscopic pancreatic biopsy is a useful and safe technique in healthy cats.

Double-phase parathyroid scintigraphy in dogs using technetium-99M-sestamibi.

The purpose of this study was to evaluate the utility of double-phase parathyroid scintigraphy using 99mTc-sestamibi for detecting and localizing hyperfunctioning parathyroid glands in hypercalcemic dogs. Fifteen hypercalcemic dogs that underwent parathyroid scintigraphy were included in this study: 3 dogs with hypercalcemia of malignancy, and 12 dogs with hyperfunctioning parathyroid tissue (parathyroid adenoma or parathyroid hyperplasia). The presence of parathyroid adenoma or parathyroid hyperplasia was documented by histopathologic examination. In 3 dogs with hypercalcemia of malignancy, parathyroid scintigraphy was negative for hyperfunctioning parathyroid tissue and the scans were classified as true negative. Parathyroid scintigraphy correctly identified the presence and location of hyperfunctioning parathyroid tissue in only 1 of 6 dogs with a parathyroid adenoma. False positive and false negative results occurred in dogs with parathyroid adenomas. Parathyroid scintigraphy failed to detect hyperfunctioning parathyroid tissue in 5 of 6 dogs with parathyroid hyperplasia and were classified as false negative. False positive results were obtained in the remaining dog with parathyroid hyperplasia. Sensitivity of parathyroid scintigraphy for detecting and localizing hyperfunctioning parathyroid tissue was 11%, specificity was 50%, and overall accuracy was 27%. Positive and negative predictive value were 25% and 27%, respectively. Sensitivity for detection of parathyroid adenomas was 25%, and sensitivity for detection of hyperplastic glands was 0 %. Results of this study indicate that double-phase parathyroid scintigraphy does not appear to have acceptable accuracy in detecting hyperfunctioning parathyroid glands in dogs. Due to the poor sensitivity and specificity of the technique in dogs, parathyroid scintigraphy is not recommended for definitive identification of abnormal parathyroid glands as the cause of hypercalcemia in dogs.

Changes in rectal temperature and hematologic, biochemical, blood gas, and acid-base values in healthy Labrador Retrievers before and after strenuous exercise.

OBJECTIVE: To measure changes in rectal temperature and hematologic, biochemical, blood gas, and acid-base values before and after exercise. ANIMALS: 14 healthy adult Labrador Retrievers. PROCEDURE: Dogs exercised continuously for 10 minutes by repeatedly retrieving a dummy thrown approximately 40 to 50 yards on land. The ambient temperature during each exercise period was recorded. Rectal temperature, pulse, and respiratory rate were measured; CBC and serum biochemical profile were determined; and arterial blood gas tensions, acid-base status, and plasma lactate and pyruvate concentrations were measured at rest and immediately after exercise. Rectal temperature, pulse, respiratory rate, and lactate and pyruvate concentrations were evaluated at intervals up to 120 minutes after exercise. RESULTS: Immediately after exercise, rectal temperature increased markedly; ambient temperature did not affect rectal temperature. Arterial blood pH and PaO2 were significantly increased after exercise, and PaCO2 and bicarbonate concentration were significantly decreased after exercise. Also, statistically, but not clinically, significant increases were observed in RBC, WBC, and segmented neutrophil counts; hemoglobin, total protein, and serum sodium and potassium concentrations; PCV; anion gap; and creatine kinase activity. Plasma lactate and pyruvate concentrations increased significantly after exercise, but there was no change in the lactate-to-pyruvate ratio. CONCLUSION AND CLINICAL RELEVANCE: Reference values for healthy Laborador Retrievers during a standardized exercise protocol were established to compare data obtained from Laborador Retrievers with exercise intolerance and collapse. Important characteristics of lactate and pyruvate metabolism were documented that will enable more precise evaluation of exercise intolerance in this breed.