Prevalence of incomplete ossification of the humeral condyle and other abnormalities of the elbow in English Springer Spaniels.

OBJECTIVES: To determine the prevalence of incomplete ossification of the humeral condyle (IOHC) and other osseous abnormalities of the elbow in English Springer Spaniels with no history of lameness. METHODS: Prospective observational study of English Springer Spaniels with no recent history of lameness. Computed tomography scans of both elbows were obtained from dogs older than six months of age which were anaesthetized or sedated for reasons unrelated to this study. Computed tomography scans were reviewed for the presence of IOHC and other abnormalities of the elbow. Radioulnar incongruity (RUI) measurements from normal elbows were compared to elbows with IOHC and elbows with medial coronoid process (MCP) abnormalities. RESULTS: Computed tomography scans from 50 dogs (100 elbows) were reviewed. The prevalence of IOHC was 14% (8 elbows in 7 dogs). All condylar fissures were incomplete with a mean length of 2.6 mm. Fifty percent of the dogs (44% of elbows) had abnormalities of the medial coronoid process and 60% of the elbows had periarticular osteophytes. Group RUI meansurements for IOHC and MCP were not significantly different from normal elbows. CLINICAL SIGNIFICANCE: Small IOHC fissures, periarticular osteophytes and MCP abnormalities may be identified in English Springer Spaniels without forelimb lameness. Abnormalities of the MCP are more common than IOHC.

Multimodality image fusion to facilitate anatomic localization of 99mTC-pertechnetate uptake in the feline head.

99mTc-pertechnetate is excreted in humans by the thyroid glands, gastric mucosa, salivary glands, choroid plexus, and sweat glands. Uptake attributed to the zygomatic and molar salivary glands is used commonly as a reference to assess thyroid uptake and differentiate euthyroid from hyperthyroid cats. However, the exact location and origin of uptake of 99mTc-pertechnetate in the head during thyroid scintigraphy in cats remains uncertain. The purpose of this study was to localize uptake of 99mTc-pertechnetate in the head of the cat using multimodality image fusion. Computed tomography (CT), magnetic resonance (MR), and single photon emission tomography (SPECT) imaging were performed successively in two cats during the same anesthesia procedure. Transverse, dorsal, and sagittal images were reconstructed for each modality. Images were rescaled and fused manually. The anatomic location of focal 99mTc activity in SPECT images was identified in CT and MR images. Four major and four minor focal areas of uptakes were identified in the head in both cats. A rostral conical-shaped activity was identified in the nasal cavity. Two symmetric focal areas of uptakes seen in the soft tissues in the ventro-caudal retro-bulbar region, and rostro-medial to the vertical ramus of the mandible were attributed to zygomatic salivary glands. A central focal activity located ventral and caudal to the zygomatic uptake was located in the nasopharynx and soft palate. Minor symmetric areas of uptake identified in the retromandibular region were attributed to parotid and mandibular salivary glands. Minor symmetric areas of uptake identified in the region of the mandible were attributed to molar salivary glands. No focal area of uptake was identified in the brain.

Exercise-induced hyperkalemia in hypothyroid dogs.

We investigated the effect of hypothyroidism in dogs on (1) the Na+-, K+ -ATPase concentration in skeletal muscle, and (2) potassium (K+) homeostasis at rest and during exercise. Prior to and 1 year after induction of hypothyroidism by surgery and subsequent radiothyroidectomy, the Na+-, K+ -ATPase concentrations were quantified in biopsies of sternothyroid muscles of seven Beagle dogs by measuring [3H]ouabain binding capacity. In addition, plasma K+ concentrations were measured at rest and after treadmill exercise in six hypothyroid and seven euthyroid Beagle dogs. During hypothyroidism, the mean Na+ -, K+ -ATPase concentration in muscle biopsies was 41% lower than during euthyroidism. The mean resting plasma K+ value of the hypothyroid dogs was significantly (14%) higher than that of the euthyroid dogs. In the hypothyroid dogs, plasma K+ concentration increased significantly during exercise, whereas there was no rise in the euthyroid dogs. The rise in plasma K+ concentration could not be ascribed to muscle damage, as plasma creatine kinase concentrations remained within reference range. Also renal K+ retention was an unlikely explanation, as plasma aldosterone concentration and plasma renin activity rather increased than decreased during exercise. In conclusion, hypothyroid dogs tend to develop hyperkalemia during exercise, which for a large part can be explained by the severe reduction of the Na+ -, K+ -ATPase capacity in the skeletal muscle pool.