Percent recovery of insulin from two different concentrations (3 U/250 mL and 45 U/250 mL) of regular insulin solutions prepared for continuous rate infusion.

OBJECTIVE: To compare the percent recovery of regular insulin prepared for administration as a continuous rate infusion (CRI) using 2 different concentrations, 3 and 45 U in 250 mL 0.9% saline. DESIGN: In vitro experiment SETTING: Privately-owned emergency and referral teaching hospital. ANIMALS: None INTERVENTION: Commercial 250 mL 0.9% sodium chloride IV fluid bags were injected with either 3 U (solution bag A) or 45 U (solution bag B) of regular insulin. The insulin concentration was measured in each bag. A fluid administration and extension set were connected to each bag and 50 mL was drained through the IV tubing. The insulin concentration was then measured from samples post washout. MEASUREMENTS AND MAIN RESULTS: Comparison of the concentration of insulin injected into the bag and concentration of insulin in the bag showed that there was a 29.7 and 37.3% recovery of insulin from solution bag A and solution bag B, respectively. Comparison of the concentration of insulin injected into the bag and concentration of insulin in the post 50-mL washout samples showed that there was an 11.9 and 30.6% recovery of insulin from bags A and B, respectively. CONCLUSIONS: Substantially more insulin was available after a 50-mL washout from solution bag B compared to solution bag A. Insulin binding to the IV bag and fluid administration set is likely the cause of this difference. CLINICAL SIGNIFICANCE: Patients receiving lower concentrations of insulin as a CRI, such as might be prescribed for cats and small dogs may require longer time for resolution of hyperglycemia and ketonemia.

Analytic performance evaluation of a veterinary-specific ELISA for measurement of serum cortisol concentrations of dogs.

OBJECTIVE To investigate the precision of an ELISA for measurement of serum cortisol concentration (SCC) in dogs, assess agreement between this ELISA and 2 validated chemiluminescence assays (CLAs), and evaluate the clinical implications of any bias associated with this ELISA when measuring SCC in dogs. DESIGN Evaluation study. SAMPLE 75 stored, frozen serum samples from client-owned dogs. PROCEDURES Enzyme-linked immunosorbent assay precision was evaluated by measuring SCC of pooled serum samples. Agreement with standard methods was evaluated with Spearman rank correlation, Passing-Bablok regression, and Bland-Altman analysis to compare SCCs obtained with the ELISA and the 2 CLAs. An error grid was used to evaluate identified bias. RESULTS Within-laboratory coefficients of variation for pooled serum samples with low, medium, and high SCCs were 21.4%, 28.9%, and 13.0%, respectively. There was a high correlation between ELISA results (for all samples combined) and results of the 2 CLAs (CLA 1, r = 0.96; CLA 2, r = 0.97), but constant and proportional biases between the ELISA and CLAs were present at all concentrations. Clinically important disagreement between ELISA results and CLA results occurred in 16 of 63 (25%) samples, particularly with low and high SCCs. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that the rate of clinical disagreement between the ELISA and CLAs was sufficiently high to recommend that equivocal results obtained with the ELISA be confirmed by a reference laboratory. Further evaluation of analytic performance of the ELISA should focus on samples with very high and very low SCCs.

Thyrotoxicosis induced by excessive 3,5,3'-triiodothyronine in a dog.

CASE DESCRIPTION A 7-year-old castrated male Havanese was evaluated at a veterinary teaching hospital because of a 12-week history of hyperactivity, aggression, and progressive weight loss despite a healthy appetite. CLINICAL FINDINGS Tachycardia was the only remarkable finding during physical examination. Serum 3,5,3'-triiodothyronine (T3) and free T3 concentrations were markedly increased, and thyroxine (T4), free T4, and thyroid-stimulating hormone concentrations were at or decreased from the respective reference ranges. Thyroid scintigraphy revealed suppressed uptake of sodium pertechnetate Tc 99m by the thyroid gland but no ectopic thyroid tissue, which was indicative of thyrotoxicosis induced by an exogenous source of T3. TREATMENT AND OUTCOME The dog was hospitalized for 24 hours, and its diet was changed, after which the clinical signs rapidly resolved and serum T3 and free T3 concentrations returned to within the respective reference ranges. This raised suspicion of an exogenous source of T3 in the dog's home environment. Analysis of the commercial beef-based canned food the dog was being fed revealed a high concentration of T3 (1.39 µg/g) and an iodine (82.44 µg/g) concentration that exceeded industry recommendations. No other source of T3 was identified in the dog's environment. CLINICAL RELEVANCE To our knowledge, this is the first report of clinical thyrotoxicosis in a dog induced by exogenous T3, although the source of exogenous T3 was not identified. This case highlights the importance of measuring serum T3 and thyroid-stimulating hormone concentrations in addition to T4 and free T4 concentrations when there is incongruity between clinical findings and thyroid function test results.

[Alimentary thyrotoxcicosis in two dogs]. / Alimentäre Thyreotoxikose bei zwei Hunden.

Two dogs with increased thyroxin concentrations compatible with hyperthyroidism were referred for further examinations. One dog displayed clinical signs of hyperthyroidism. Based on history, clinical examination, laboratory evaluation and scintigraphy an alimentary thyrotoxicosis was identified. It was caused by feeding a BARF diet containing thyroidal tissue in one dog and by conventional dog food in the other patient. After changing the diet the clinical signs resolved in the affected dog. A control examination revealed thyroxin concentrations within the reference range in both dogs.

Reduction of serum 25-hydroxyvitamin D concentrations with intravenous lipid emulsion in a dog.

The recommended daily allowance of vitamin D has been increased. Toxicosis in pets may increase as a result. A dog ingested ~ 200 000 IU of vitamin D, serum concentrations were above the reference range (RR) and decreased to the RR after lipid treatment. This is the first known report of lipid treatment for hypervitaminosis D.

Réduction des concentrations sériques de 25-hydroxyvitamine D à l'aide d'une émulsion intraveineuse de lipides chez un chien. L'apport quotidien recommandé de vitamine D a été accru. La toxicose chez les animaux de compagnie peut augmenter en raison de cette hausse. Un chien a ingéré ~ 200 000 UI de vitamine D, les concentrations sériques étaient supérieures à la fourchette de référence (FR) et a chuté à la FR après le traitement aux lipides. Il s'agit du premier rapport connu de traitement aux lipides pour la toxicose à l'hypervitaminose D.(Traduit par Isabelle Vallières).

THE EFFECT OF UVB RADIATION ON SERUM VITAMIN D AND IONIZED CALCIUM IN THE AFRICAN SPOONBILL (PLATALEA ALBA).

Metabolic bone disease (MBD) was diagnosed in two chicks produced by a captive breeding colony of African spoonbills (Platalea alba). The birds were housed indoor during the winter breeding season and had no access to natural sunlight. When the index cases occurred, the nesting birds and chicks had a mean 25-hydroxyvitamin D (25-OHD) concentration of 9.9 ± 2.7 nmol/L and a mean ionized calcium (iCa) concentration of 0.98 ± 0.12 mmol/L (winter pretreatment). For comparison purposes, serum was collected the following summer; mean 25-OHD was 20.8 ± 3.9 nmol/L and mean iCa was 1.32 ± 0.05 mmol/L (summer). During the following breeding season, ultraviolet B (UVB) lighting was provided to the flock, resulting in a mean 25-OHD of 19.0 ± 5.6 nmol/L and mean iCa of 1.23 ± 0.06 mmol/L (winter treatment 1). Both 25-OHD and iCa were significantly higher compared with winter pretreatment, and 25-OHD was not significantly different from summer, indicating that treatment during the winter months succeeded in increasing 25-OHD levels to summer levels. However, winter treatment 1 and summer iCa were significantly different. During the next breeding season (winter treatment 2), the birds were exposed to a light with higher UVB output. The mean 25-OHD of the flock was 16.5 ± 7.2 nmol/L, and the mean iCa increased to 1.34 ± 0.04 mmol/L. Both were comparable to summer values. Healthy chicks were hatched during both breeding seasons, and no further cases of MBD occurred during the course of the study. Provision of a UVB light source to captive African spoonbills maintained indoors during the winter months can increase 25-OHD and iCa to levels equivalent to those seen in the summer months, when birds have unrestricted access to natural sunlight. UVB lighting is recommended for all breeding spoonbills that do not have access to natural sunlight.

Serum transthyretin concentration is decreased in dogs with nonthyroidal illness.

BACKGROUND: Hypothyroidism in dogs is often difficult to diagnose owing to nonspecific clinical signs and laboratory test results that can be mimicked by nonthyroidal illness (NTI). Thyroxine (T4) circulates in blood mainly bound to T4-binding globulin and, to a lesser degree, transthyretin (TTR) and albumin. The concentration of total T4 depends on the concentrations of these binding proteins. OBJECTIVES: We hypothesized that dogs with NTI and decreased serum total T4 concentrations would have decreased serum TTR concentrations. The objective of the study was to measure and compare serum TTR concentrations in healthy dogs, in dogs with NTI and low serum T4 concentrations, and in dogs with hypothyroidism. METHODS: Assignment of dogs to 3 groups was based on physical examination and serum concentrations of T4 and TSH (mean ± SD): for healthy dogs (n = 13), T4 was 24.8 ± 3.6 nmol/L and TSH was 0.15 ± 0.08 µg/L; for dogs with NTI and low T4 (n = 20), T4 was 3.2 ± 3.0 nmol/L and TSH was 0.18 ± 0.13 µg/L; and for hypothyroid dogs (n = 19), T4 was 5.3 ± 4.3 nmol/L and TSH was 2.33 ± 1.90 µg/L). TTR concentrations in serum were determined semiquantitatively using western blot analysis. RESULTS: Serum TTR concentration (mean ± SD) was decreased in the dogs with NTI (24.8 ± 7.9 mg/L) compared with that of hypothyroid dogs (41.1 ± 21.4 mg/L, P = .0035). Differences were not found between TTR concentrations in clinically healthy dogs (33.3 ± 10.1 mg/L) and hypothyroid dogs or dogs with NTI. CONCLUSIONS: Serum TTR concentrations were significantly decreased in dogs with NTI and low T4 compared with concentrations in hypothyroid dogs. Additional studies should be done to determine if TTR concentrations can discriminate between dogs with NTI and low T4 and dogs with primary hypothyroidism.