Development and validation of a radioimmunoassay for thyrotropin in cattle

In mammals, thyrotropin, or thyroid-stimulating hormone (TSH), assay is used for the diagnosis of primary hypothyroidism. Hypothyroidism is the most common type of thyroid disorder in cattle. The aim of this study was to develop and validate, under physiologic and pathologic conditions, a radioimmunoassay (RIA) for bovine TSH (bTSH). Double RIA was performed with purified bTSH and specific bovine antiserum. Laboratory validation included research of minimal detection limit, accuracy, and reproducibility. The physiologic validation included a thyrotropin-releasing hormone (TRH) challenge performed on euthyroid cows and a follow-up of bTSH concentration over a 24-hour period. Furthermore, bTSH concentration was assayed in a large population of healthy dairy and beef cows to define reference interval. The pathologic validation was made by assaying bTSH and thyroid hormones on healthy and goitrous newborn calves. The minimum detection limit (MDL) for bTSH assay was 1.3 microU/ml. The recovery was 101% to 106%. The intra- and interassay coefficients of variation (CVs) ranged from 5% to 11% and 11% to 15%, respectively. The RIA covered the whole range of physiologic bTSH values, as shown by bTSH values induced by TRH-challenge. A pulsatile secretion of bTSH was observed, accompanied by a diurnal variation with lower night values than day values. Reference intervals of bTSH ranged from 1.3 to 13.0 microU/ml for beef and dairy breeds. Finally, bTSH easily discriminated goitrous newborn calves from healthy ones, leading to the definition of a cutoff value of 35 microU/ml. The bTSH assay positively reacted to physiologic and pathologic conditions. The accuracy and precision of the RIA were satisfying

A prospective study on canine atopic dermatitis and food-induced allergic dermatitis in Switzerland

Canine atopic dermatitis sensu stricto and food-induced allergic dermatitis are common canine skin conditions, which are often considered clinically undistinguishable. Several attempts have been made to describe populations of atopic dogs and determine breed predisposition but the results were often biased by the use of hospital populations as control group. The present study aims to describe a population of Swiss atopic and food-allergic dogs and to compare it with a data set representing more than 85% of all Swiss dogs. The study, which was carried out during 1 year in several practices and teaching hospital in Switzerland, describes a group of 259 allergic dogs, determines breed predisposition for atopic dermatitis and food-induced allergic dermatitis, compares the clinical signs and features of both conditions, and outlines the clinical picture of five frequently affected breeds

Effectiveness of low dose immunotherapy in the treatment of canine atopic dermatitis: a prospective, double-blinded, clinical study

The definitive version is available at www3.interscience.wiley.comThere are anecdotal reports of increased effectiveness of allergen-specific immunotherapy (ASIT) in dogs with doses of vaccine lower than that recommended by the manufacturers. However, no controlled studies have been carried out. The aim of this prospective, double-blinded study was to evaluate whether induction and maintenance with low dose (LD) ASIT resulted in a different success rate compared with the standard dose (SD). Twenty-seven dogs with confirmed atopic dermatitis were allocated by block randomization to two groups. One group (n = 13) received SD ASIT; the other group (n = 14) received LD ASIT (1/10 of the SD) following the same frequency protocol. Cases were graded at 0, 3, 6 and 9 months for clinical signs using a modified canine atopic dermatitis extent and severity index (mCADESI) and for pruritus using a 0–5 descriptor scale. There were no significant differences between the groups in the pruritus and mCADESI scores (P > 0.155) at the end of the study, and the changes in pruritus (P > 0.920) and mCADESI (P > 0.296) scores from the beginning to the end of the study were similar in both groups. Pruritus scores in both groups did not change during the study (P > 0.052). However, significant reductions in mCADESI scores were seen in both groups (P < 0.032). Six dogs achieved a final pruritus score of 0, six achieved a reduction in pruritus score and 15 did not improve or worsened. There was, therefore, no evidence that LD ASIT is more effective than the standard protocol.Silvia Colombo, Peter B. Hill, Darren J. Shaw and Keith L. Thoda