Clinical Evaluation of a Novel Liquid Formulation of L-Thyroxine for Once Daily Treatment of Dogs with Hypothyroidism

peer reviewed[en] BACKGROUND: A liquid solution of levothyroxine (L-T4) is available for treatment of canine hypothyroidism. HYPOTHESIS: Once daily oral administration of a liquid L-T4 solution is effective and safe for controlling hypothyroidism in dogs. ANIMALS: Thirty-five dogs with naturally occurring hypothyroidism. METHODS: Dogs received L-T4 solution PO once daily at a starting dosage of 20 microg/kg body weight (BW). The dose was adjusted every 4 weeks, based on clinical signs and peak serum total T4 (tT4) concentrations. Target peak serum tT4 and thyroid stimulating hormone (TSH) concentrations, 4-6 hours posttreatment, were 35-95 nmol/L and < 0.68 ng/mL, respectively. Dogs were followed for up to 22 weeks after establishment of the maintenance dose. RESULTS: Clinical signs of hypothyroidism improved or resolved in 91% of dogs after 4 weeks of L-T4 treatment at 20 microg/kg once daily. The maintenance dose was established in 76, 94, and 100% of dogs after 4, 8, and 12 weeks of treatment, respectively. This was 20 microg L-T4/kg BW for 79% of the dogs, 30 microg/kg BW for 15%, and 10-15 microg/kg BW in the remaining 6%, once daily. Thereafter, median peak tT4 and TSH concentrations were 51 nmol/L and 0.18 ng/mL, respectively, and remained stable during the 22-week follow-up; clinical signs did not recur. CONCLUSIONS AND CLINICAL IMPORTANCE: All of the hypothyroid dogs had rapid clinical and hormonal responses to supplementation with the PO-administered L-T4 solution. The starting dosage of 20 microg L-T4/kg BW once daily was suitable for 79% of dogs

Treatment of 46 cats with porcine lente insulin - a prospective, multicentre study

This prospective, multicentre, non-blinded, open study followed 46 cats with diabetes mellitus during treatment with porcine lente insulin (also known as porcine insulin zinc suspension, Caninsulin (R), Intervet) for 16 1 weeks (stabilization phase), with additional monitoring of some cats (n = 23) for a variable period. At least three of the following were present at initial presentation: appropriate history of clinical signs consistent with diabetes mellitus, glucosuria, blood glucose greater than 15 mmol/l and fructosamine greater than 380 mu mol/l. Insulin treatment was started at a dose rate of 0.25-0.5 IU/kg body weight twice daily, with a maximum starting dose of 2 IU/ injection. Twenty-eight of the cats were classed as reaching clinical stability during the study, in 23 of these cats this was during the stabilization phase. Seven cats went into remission during the stabilization phase and one of the cats in week 56. Clinical signs of hypoglycaemia, significantly associated with a dose of 3 units or 0.5 IU/kg or more per cat (twice daily), were observed in nine of the 46 cats during the stabilization phase and concomitant biochemical hypoglycaemia was recorded in most cases. Biochemical hypoglycaemia, recorded in 6% of the blood glucose curves performed during the stabilization phase, was significantly associated with a dose rate of 0.75 IU/kg or more twice daily. This further highlights the need for cautious stepwise changes in insulin dose. The protocol used in the present study is suitable for and easy to use in practice. This study confirmed the efficacy and safety of porcine lente insulin (Caninsulin) in diabetic cats under field conditions. (C) 2008 ESFM and AAFR Published by Elsevier Ltd. All rights reserved.[...

Prevalence of and risk factors for feline hyperthyroidism in South Africa

Poster presented at the University of Pretoria, Faculty of Veterinary Science Faculty Day, August 25, 2016, Pretoria, South Africa.Feline hyperthyroidism is a disease of middle-aged to older cats that has shown a marked increase in worldwide incidence within the last three decades as well as a marked geographic variation in prevalence. The exact pathogenesis of the disease still remains obscure and despite a plethora of epidemiological studies, clear risk factors have not been identified. The purpose of this study was to determine the prevalence of feline hyperthyroidism in South Africa and to identify potential risk factors. Serum total thyroxine (tT4) and thyroid stimulating hormone (cTSH) were measured in 302 cats aged 9 years and older that were presented at various veterinary clinics. In a few cats, serum free thyroxine (fT4) was also measured. At the time of blood sampling a questionnaire was completed regarding vaccination history, internal and external parasite control, diet and environment. The prevalence of hyperthyroidism (tT4> 50nmol/L or tT4 between 30-50 nmol/L with cTSH 50pmol/L) within this population was 7.0% with no significant difference in prevalence between healthy (5.1%) and sick (8.2%) cats. Cats ≥ 12years of age (OR= 4.3, p= 0.02) and cats with canned food in their diet (OR= 2.1, p= 0.1) were more likely to be diagnosed with hyperthyroidism. No significant relationship between vaccinations, parasite control or indoor environment and hyperthyroidism was observed. Hyperthyroid cats were more likely to present with weight loss (OR= 3.2, p= 0.01) and with a heart rate ≥ 200bpm (OR= 5, p= 0.01) than cats without the disease.The prevalence of feline hyperthyroidism in South Africa appears to be similar to that in cats in Japan and Portugal but less than that in cats in the UK and Germany. Risk factors for hyperthyroidism, previously found in other studies, specifically older age and eating canned food was present in this study population.ab201

A targeted metabolomic protocol for short-chain fatty acids and branched-chain amino acids

Research in obesity and metabolic disorders that involve intestinal microbiota demands reliable methods for the precise measurement of the short-chain fatty acids (SCFAs) and branched-chain amino acids (BCAAs) concentration. Here, we report a rapid method of simultaneously determining SCFAs and BCAAs in biological samples using propyl chloroformate (PCF) derivatization followed by gas chromatography mass spectrometry (GC-MS) analysis. A one-step derivatization using 100 µL of PCF in a reaction system of water, propanol, and pyridine (v/v/v = 8:3:2) at pH 8 provided the optimal derivatization efficiency. The best extraction efficiency of the derivatized products was achieved by a two-step extraction with hexane. The method exhibited good derivatization efficiency and recovery for a wide range of concentrations with a low limit of detection for each compound. The relative standard deviations (RSDs) of all targeted compounds showed good intra- and inter-day (within 7 days) precision (< 10%), and good stability (< 20%) within 4 days at room temperature (23–25 °C), or 7 days when stored at −20 °C. We applied our method to measure SCFA and BCAA levels in fecal samples from rats administrated with different diet. Both univariate and multivariate statistics analysis of the concentrations of these target metabolites could differentiate three groups with ethanol intervention and different oils in diet. This method was also successfully employed to determine SCFA and BCAA in the feces, plasma and urine from normal humans, providing important baseline information of the concentrations of these metabolites. This novel metabolic profile study has great potential for translational research