Trilostane treatment of a dog with functional adrenocortical neoplasia.

A 13-year-old, crossbreed dog presented with a history of recent onset polydipsia, progressive lethargy, weakness and reduced appetite. Blood tests showed raised concentrations of alkaline phosphatase and alanine aminotransferase with marginally low serum potassium. There was a leucocytosis with a mature neutrophilia and no eosinophils. Endocrine tests showed a normal aldosterone concentration and an exaggerated adrenocorticotropic hormone (ACTH) stimulation test, consistent with a diagnosis of hyperadrenocorticism (HAC). A diagnosis of adrenal-dependent HAC was made, based on the presence of a calcified mass involving the left adrenal gland, and hepatomegaly, on radiography and ultrasonography. The owners declined surgical adrenalectomy. Medical management with trilostane rapidly improved the clinical signs and normalised the serum chemistry. ACTH stimulation tests showed an improvement in post-ACTH cortisol concentrations and were used to make dose adjustments where necessary. At the time of writing, no adverse side effects had been seen and the dog remained well after 80 weeks of treatment.

Trilostane treatment of 78 dogs with pituitary-dependent hyperadrenocorticism.

The efficacy of trilostane in the treatment of canine pituitary-dependent hyperadrenocorticism (PDH) was evaluated in 78 dogs with the condition which were treated for up to three years. The drug appeared to be well tolerated by almost all the dogs, and only two developed clinical signs and biochemical evidence of hypoadrenocorticism. Polyuria and polydipsia completely resolved in 70 per cent of the dogs that had these problems, and skin changes resolved in 62 per cent of the dogs that had skin abnormalities. There was a significant reduction (P<0.001 in each case) in both the mean basal and post-adrenocorticotrophic hormone (ACTH) cortisol concentrations after a mean of 12.3 days of treatment. The post-ACTH cortisol concentration decreased to less than 250 nmol/litre in 81 per cent of the dogs within one month of the start of treatment and in another 15 per cent at some later time. The median survival time of the 26 dogs which died was 549 days, and 51 of the dogs were alive at the completion of the study. One was lost to follow up after 241 days treatment.

Frequency of pulmonary mineralization and hypoxemia in 21 dogs with pituitary-dependent hyperadrenocorticism.

The purpose of this study was to determine the frequency of hypoxemia and pulmonary mineralization using 99mTc-methylene diphosphonate (99mTc-MDP) in dogs with pituitary-dependent hyperadrenocorticism (PDH). Twenty-one dogs with PDH were prospectively evaluated using thoracic radiography, arterial blood gas analysis, and bone phase and pulmonary perfusion scintigraphy (using 99mTc-macro-aggregated albumin [99mTc-MAA]). The radiographs and bone and perfusion studies were evaluated subjectively. An averaged quantitative count density ratio was calculated between the thorax and cranial thoraco-lumbar vertebrae from lateral thoracic 99mTc-MDP images. Thoracic:vertebral ratios were calculated using 99mTc-MDP studies from 21 control dogs. The thoracic:vertebral ratios were compared between the 2 groups (PDH and control). The mean age (+/-SD) of the 21 PDH dogs was 10.2 (+/-3) years, whereas the mean age of the control group was 9.8 (+/-3) years. Seven of the 21 dogs with PDH were hypoxemic (defined as an arterial partial pressure of oxygen [PaO2] < 80 mm Hg) with an average PaO2 (+/-SD) of 62 (+/-15) mm Hg. Of the 7 hypoxemic dogs, 2 were found to have pulmonary mineralization based on bone scintigraphic images. Pulmonary perfusion abnormalities were not identified using 99mTc-MAA in any of the 21 PDH dogs. Six PDH dogs had an abnormal interstitial pulmonary pattern and 5 of these dogs were hypoxemic. The average quantitative thoracic:vertebral ratio was not significantly different between the PDH and control dogs (0.5 +/- 0.4 versus 0.4 +/- 0.1, P = .16). Causes of hypoxemia other than pulmonary thromboembolism should be considered in dogs with PDH. Pulmonary mineralization may contribute to hypoxemia in dogs with PDH.

Evaluation of urine protein content in dogs with pituitary-dependent hyperadrenocorticism.

OBJECTIVE: To evaluate urine protein content in dogs with pituitary-dependent hyperadrenocorticism (PDHAC) and to determine the effect of mitotane administration on proteinuria in these dogs. DESIGN: Prospective case series. ANIMALS: 16 dogs with PDHAC were evaluated (age range, 7 to 14 years; mean age, 10 years; female-to-male ratio, 2.2:1). PROCEDURE: Urine protein-to-creatinine (UPC) ratios and 24-hour urine protein excretion (24-hour UPE) values were measured before beginning treatment with mitotane and after establishing appropriate maintenance treatment. RESULTS: Before treatment, UPC ratios ranged from 0.03 to 4.16 (16 dogs, median, 0.695; reference range value, UPC ratio < 0.5; questionable value, UPC ratio > 0.5 but < 1.0; high value, UPC ratio > 1.0). Seven dogs had proteinuria with UPC ratios > 1.0. Twenty-four-hour UPE values ranged from 0.67 to 61.7 mg/kg of body weight/d (0.30 to 28.0 mg/lb/d; 13 dogs, median, 9.7 mg/kg/d [4.4 mg/lb/d]; reference value, 24-hour UPE value, < 20 mg/kg/d [9.1 mg/lb/d]). Five dogs with high UPC ratios also had high values for 24-hour UPE. After establishment of maintenance treatment with mitotane (median, 7 weeks; mean, 7.3 weeks), UPC ratios ranged from 0.02 to 6.5 (16 dogs, median, 0.36). Five dogs continued to have high UPC ratios. Values of 24-hour UPE ranged from 0.47 to 122 mg/kg/d (0.21 to 55.5 mg/lb/d; 13 dogs, median, 5.1 mg/kg/d [2.3 mg/lb/d]). Three dogs continued to have high 24-hour UPE values. Significant differences were not found between dogs before and after treatment with mitotane in terms of UPC ratios or 24-hour UPE values. CLINICAL IMPLICATIONS: In dogs with PDHAC and proteinuria, UPC ratios should be monitored closely. Some dogs with PDHAC may have a decrease in urine protein content following treatment with mitotane. We suggest that renal biopsies be considered in those dogs with progressive increases in UPC ratios.

Architectural and histochemical analysis of the biceps brachii muscle of the horse.

The biceps brachii of horses is a complex muscle subdivided into two heads which may subserve distinct functions. The lateral head contains a large percentage of type I myofibers. This region is largely composed of short fibers (5-7 mm long) arranged in a pinnate fashion and heavily invested with connective tissue. The medial head contains fewer type I fibers and is composed of relatively longer myofibers (15-20 mm long), also arranged in a pinnate fashion but less heavily invested with connective tissue. It is hypothesized that the lateral muscle head of biceps brachii contributes to the postural role of the muscle in the forelimb passive stay apparatus. The medial head, with its longer fibers and generally fast fiber population may be most important during dynamic activity such as walking, trotting and running.