Objective—To investigate the effects of insulin detemir in dogs with diabetes mellitus.
Design—Prospective, uncontrolled clinical trial.
Animals—10 client-owned dogs with naturally occurring diabetes mellitus.
Procedures—Dogs were treated with insulin detemir SC every 12 hours for 6 months. Follow-up evaluations were done at 1, 2, 4, 12, and 24 weeks and included evaluation of clinical signs and measurement of blood glucose concentration curves and serum fructosamine concentrations.
Results—Insulin detemir administration resulted in a significant decrease in blood glucose and serum fructosamine concentrations at 6 months, compared with pretreatment values. Median insulin dosage at the end of the study was 0.12 U/kg (0.055 U/lb; range, 0.05 to 0.34 U/kg [0.023 to 0.155 U/lb], SC, q 12 h). Hypoglycemia was identified in 22% (10/45) of the blood glucose concentration curves, and 6 episodes of clinical hypoglycemia in 4 dogs were recorded. A subjective improvement in clinical signs was observed in all dogs during the 6-month study period. On the basis of clinical signs and blood glucose concentration curves, efficacy of insulin detemir at the end of the study was considered good in 5 dogs, moderate in 3, and poor in 2.
Conclusions and Clinical Relevance—Results suggested that SC injection of insulin detemir every 12 hours may be a viable treatment for diabetes mellitus in dogs. Insulin detemir dosages were lower than reported dosages of other insulin types needed to maintain glycemic control, suggesting that insulin detemir should be used with caution, especially in small dogs.
Objective—To evaluate 4 methods used to measure plasma insulin-like growth factor (IGF) 1 concentrations in healthy cats and cats with diabetes mellitus or other diseases.
Animals—39 healthy cats, 7 cats with diabetes mellitus, and 33 cats with other diseases.
Procedures—4 assays preceded by different sample preparation methods were evaluated, including acid chromatography followed by radioimmunoassay (AC-RIA), acid-ethanol extraction followed by immunoradiometry assay (AEE-IRMA), acidification followed by immunochemiluminescence assay (A-ICMA), and IGF-2 excess followed by RIA (IE-RIA). Validation of the methods included determination of precision, accuracy, and recovery. The concentration of IGF-1 was measured with all methods, and results were compared among cat groups.
Results—The intra-assay coefficient of variation was < 10% for AC-RIA, A-ICMA, and AEE-IRMA and 14% to 22% for IE-RIA. The linearity of dilution was close to 1 for each method. Recovery rates ranged from 69% to 119%. Five healthy cats had IGF-1 concentrations > 1,000 ng/mLwith the AEE-IRMA, but < 1,000 ng/mL with the other methods. Compared with healthy cats, hyperthyroid cats had significantly higher concentrations of IGF-1 with the A-ICMA method, but lower concentrations with the IE-RIA method. Cats with lymphoma had lower IGF-1 concentrations than did healthy cats regardless of the method used.
Conclusions and Clinical Relevance—Differences in the methodologies of assays for IGF-1 may explain, at least in part, the conflicting results previously reported in diabetic cats. Disorders such as hyperthyroidism and lymphoma affected IGF-1 concentrations, making interpretation of results more difficult if these conditions are present in cats with diabetes mellitus.
Objective—To evaluate whether use of recombinant human (rh) thyroid-stimulating hormone (TSH) induces equivalent stimulation, compared with bovine TSH (bTSH), and to evaluate activity of rhTSH in dogs of various large breeds.
Animals—18 healthy research Beagles and 20 healthy client-owned dogs of various breeds with body weight > 20 kg.
Procedures—The 18 Beagles were randomly assigned to 3 groups, and each dog received either 75 μg of rhTSH, IM or IV, or 1 unit of bTSH, IM, respectively, in a crossover design. The 20 client-owned dogs received 75 μg of rhTSH, IV. Blood samples were taken before and 6 hours after TSH administration for determination of total serum thyroxine (T4) concentration. Additional blood samples were taken after 2 and 4 hours in Beagles that received rhTSH, IM.
Results—There was a significant increase in T4 concentration in all dogs, but there were no differences between values obtained after administration of bTSH versus rhTSH or IV versus IM administration of rhTSH. Although there was a significant difference in age and body weight between Beagles and non-Beagles, there was no difference in post-TSH simulation T4 concentration between the 2 groups.
Conclusions and Clinical Relevance—Results indicated an equivalent biological activity of rhTSH, compared with bTSH. Use of 75 μg of rhTSH, IV, did not induce a different magnitude of stimulation in large-breed dogs, compared with Beagles. Euthyroidism was confirmed if post-TSH simulation T4 concentration was ≥ 2.5 μg/dL and at least 1.5 times basal T4 concentration.
Objective—To evaluate the use of recombinant human (rh) thyroid-stimulating hormone (TSH) in dogs with suspected hypothyroidism.
Animals—64 dogs with clinical signs of hypothyroidism.
Procedures—Dogs received rhTSH (75 μg/dog, IV) at a dose independent of their body weight. Blood samples were taken before and 6 hours after rhTSH administration for determination of total serum thyroxine (T4) concentration. Dogs were placed into 1 of 3 groups as follows: those with normal (ie, poststimulation values indicative of euthyroidism), unchanged (ie, poststimulation values indicative of hypothyroidism; no thyroid gland stimulation), or intermediate (ie, poststimulation values between unchanged and normal values) post-TSH T4 concentrations. Serum canine TSH (cTSH) concentration was determined in prestimulation serum (ie, before TSH administration).
Results—14, 35, and 15 dogs had unchanged, normal, and intermediate post-TSH T4 concentrations, respectively. Basal T4 and post-TSH T4 concentrations were significantly different among groups. On the basis of basal serum T4 and cTSH concentrations alone, 1 euthyroid (normal post-TSH T4, low basal T4, and high cTSH concentrations) and 1 hypothyroid dog (unchanged post-TSH T4 concentration and low to with-in reference range T4 and cTSH concentrations) would have been misinterpreted as hypothyroid and euthyroid, respectively. Nine of the 15 dogs with intermediate post-TSHT4 concentrations had received medication known to affect thyroid function prior to the test, and 2 of them had severe nonthyroidal disease.
Conclusions and Clinical Relevance—The TSH-stimulation test with rhTSH is a valuable diagnostic tool to assess thyroid function in selected dogs in which a diagnosis of hypothyroidism cannot be based on basal T4 and cTSH concentrations alone.
OBJECTIVE To assess the effects of 3 contrast medium injection techniques on attenuation values for canine adrenal glands during contrast-enhanced CT.
ANIMALS 9 healthy Beagles.
PROCEDURES 3 protocols were evaluated in a randomized cross-over design study: 700 mg of iodine/kg at a constant injection rate over 20 seconds (full-dose constant rate), the same dose at a rate following an exponential decay curve over 20 seconds (full-dose decelerated rate), and 350 mg of iodine/kg at a constant injection rate over 10 seconds (half-dose constant rate). Multislice CT images were obtained before and at predetermined time points after the start of contrast medium injection.
RESULTS Median peak attenuation values were 129, 133, and 87 Hounsfield units with the full-dose constant rate, full-dose decelerated rate, and half-dose constant rate injection protocols, respectively. Peak attenuation differed significantly between the full-dose constant rate and half-dose constant rate injection protocols and between the full-dose decelerated rate and half-dose constant rate injection protocols. Median time to peak attenuation did not differ significantly among injection methods and was 30, 23, and 15 seconds for the full-dose constant rate, full-dose decelerated rate, and half-dose constant rate injections, respectively.
CONCLUSIONS AND CLINICAL RELEVANCE The dose of contrast medium and the timing of postinjection CT scanning were main determinants of peak attenuation for adrenal glands in healthy dogs; effects of the 3 injection protocols on attenuation were minor. The exponentially decelerated injection method was subjectively complex. A constant injection protocol delivering 700 mg of iodine/kg over 20 seconds, with scans obtained approximately 30 seconds after starting contrast medium injection, provided images with maximum adrenal gland attenuation values. (Am J Vet Res 2016;77:144–150)