The effects of thyroid hormones on the skin of beagle dogs

The effects of hypothyroidism on canine skin were determined by comparing morphologic, morphometric, and hair cycle differences in skin biopsy samples from 3 groups of age- and gender-matched Beagle dogs: (1) euthyroid dogs; (2) dogs made hypothyroid by administration of 131I; and (3) dogs made hypothyroid and maintained in a euthyroid state by treatment with synthetic thyroxine. After 10 months of observation, there was slower regrowth of hair 2 months after clipping in the untreated-hypothyroid dogs. Untreated-hypothyroid dogs had a greater number of follicles in telogen and fewer hair shafts (ie, a greater number of hairless telogen follicles) than did the control group. The control dogs had a greater number of telogen follicles but the same number of hair shafts as the treated-hypothyroid group. Treated-hypothyroid dogs had the greatest number of follicles in the growing stage of the hair cycle (anagen). This study suggests that, at least in Beagles, induced hypothyroidism does not affect the pelage as dramatically as has been described in naturally occurring disease. This is because normal Beagles retain hair shafts in follicles for long periods, and the alopecia of hypothyroidism appears to evolve slowly because of the prolongation of this haired telogen stage. The evaluation of thyroxine-treated hypothyroid dogs demonstrates that thyroid hormone supplementation of Beagle dogs with induced hypothyroidism stimulates hair growth.     

Results of a survey of small-animal practitioners on the perceived clinical efficacy and safety of an oral nutraceutical

A mail survey of 3080 practitioners from two sampling frames was used to determine the perceived clinical efficacy and safety of an oral nutraceutical for the treatment of degenerative joint disease (DJD) in small animals. Overall response rate was 82%, of which 64% reported that they were recommending the oral nutraceutical to their clients. There was a high variability reported between the severity of DJD and response to treatment. Sixty-eight percent of practitioners reported lame dogs older than five years to be the most responsive to treatment. Most practitioners (83%) believed response to treatment with the studied product occurred within four weeks. Practitioners using the product rated the clinical efficacy of the product to be either 'good' or 'excellent' in improving mobility, alleviating pain and improving attitude in the majority of the treated animals. No practitioner reported a worsening of pain, mobility or attitude. Self-reported adverse effects were 2% (the most common was gastrointestinal upset). The results of this survey indicated that perceived clinical efficacy of the studied nutraceutical in the treatment of DJD was regarded to be 'good' or 'excellent' by most of the practitioners who use this product and was considered to be safe with minimal side effects. This provides additional information on the product for use in planning future clinical trials.     

Cardiovascular effects of doxacurium chloride in isoflurane-anaesthetised dogs

The cardiovascular effects of doxacurium were studied in 6 isoflurane-anaesthetised dogs. Each dog was anaesthetised twice, receiving doxacurium (0.008 mg/kg bwt) or placebo iv. Dogs were ventilated to normocapnia. Heart rate, cardiac index, systolic, diastolic, and mean arterial blood pressures, stroke volume, pulmonary vascular resistance, pulmonary artery wedge pressure, systemic vascular resistance, and pulmonary arterial pressure were determined. Neuromuscular blockade was assessed using the train-of-four technique. After recording baseline values, dogs randomly received either doxacurium or placebo iv, and data were recorded at 5, 10, 15, 30, 45, 60, 75, 90, 105 and 120 min. At 120 min, dogs treated with doxacurium received edrophonìum (0.5 mg/kg bwt iv) to antagonise neuromuscular blockade; dogs treated with placebos received saline iv. No statistically significant differences were detected after doxacurium compared to placebo. In both the doxacurium and placebo groups, significant increases in systolic arterial blood pressure, cardiac index, and stroke volume and a significant decrease in systemic vascular resistance occurred with time. Doxacurium depressed twitch tension 100% in all dogs (time to maximal twitch depression, 11 ± 7 min). First twitch tension was less than 10% of baseline values in all dogs at the time (120 min) of edrophonium administration. Additional edrophonium (1.0 ± 0.4 mg/kg iv) was required to obtain a fourth twitch to first twitch ratio of greater than 0.70. In conclusion, doxacurium is a long-acting neuromuscular blocking agent with no significant cardiovascular effects in isoflurane-anesthetised dogs. In dogs, doxacurium is indicated primarily for long surgical procedures requiring neuromuscular blockade and cardiovascular stability.     

A comparison of five strategies for selecting control groups: a canine osteochondritis dissecans example

A case-control study of risk factors for osteochondritis dissecans in dogs was conducted between January 1980 and December 1987 at the Small Animal Clinic of the New York State College of Veterinary Medicine. Odds ratios and 95% confidence intervals were calculated for age, gender and breed using five different hospital based control groups. The first (1980), midpoint (1984), last year (1987), and two combined years groups (1980–1987) were selected as controls. The individual year groups and one combined years group used the first visit for each dog as the index visit. The other combined years group used a randomly selected visit for each dog.

Few differences in results were seen between control groups for age and gender. For the less common breeds of dog, the individual year control groups resulted in more variation in the odds ratios and less precision. Issues affecting the selection of hospital based control groups in companion animal epidemiology are discussed.     

Detection of White Spot Syndrome virus and Yellowhead virus in prawns imported into Australia

Objective To determine whether viable White Spot Syndrome virus (WSSV) or Yellowhead virus (YHV) were present in prawn products imported into Australia.
Procedure A sample of fourteen uncooked prawns was obtained from a consignment imported from southeast Asia. Each of the prawns was examined for WSSV by polymerase chain reaction (PCR), and then a bioassay was conducted in which a 10% homogenate of cuticular epithelium from each of the prawns was inoculated intramuscularly into healthy challenge prawns ( Penaeus monodon ) from Australia. The latter were then monitored for clinical signs of disease, and tissue samples were processed for electron microscopy, histological examination and for detection of WSSV by in situ hybridization (ISH) using a commercial kit. Limited numbers of haemolymph samples from inoculated challenge prawns were also examined by PCR for the presence of WSSV and YHV. All work was carried out under microbiologically secure conditions.
Results Results of the initial PCR examination for WSSV on the imported prawns were not definitive. However, in the bioassay, several of the challenge prawns inoculated with homogenates from the imported prawns showed clinical signs of disease (inappetence and lethargy) within 24 h post inoculation (pi) and died at 1 to 4 days pi. Tissue samples from a number of moribund prawns demonstrated lesions typical of White Spot Disease (WSD), and the presence of the virus was confirmed by electron microscopy, ISH and PCR. YHV was also demonstrated by PCR in two challenge prawns inoculated with homogenates.
Conclusion Viable WSSV and YHV were present in frozen prawn products imported into Australia for human consumption from southeast Asia. Importation of frozen infected products may present a risk of transferring virus to wild and farmed populations of crustaceans in this country. To date, WSD and Yellowhead Disease remain exotic to Australia.