Ebstein's anomaly in a beagle dog

An intact male beagle dog aged 1 year was referred because of shortness of breath, exercise intolerance and cardiac murmur. Based on the results from electrocardiography, thoracic radiography and echocardiography, the dog was diagnosed as Ebstein's anomaly. Although the orally administered digoxin, vasodilators and diuretics partially improved congestive signs, the dog became to be refractory and died 20 months after the diagnosis. Necropsy confirmed malformation and apical displacement of the basal attachment of tricuspid valve leaflets.     

Vertebral heart scale in the beagle dog

OBJECTIVE: To determine if Buchanan's vertebral heart scale can be applied to beagle dogs to establish reference values for this breed and to determine the possible influence of optimal lung inflation on the cardiac measurements. METHODS: The cardiac health of 19 beagle dogs was examined by echocardiography, electrocardiogram, non-invasive blood pressure measurement, complete blood count and serum chemistry profile. Right and left lateral recumbent radiographs of the thorax were obtained while the dogs were conscious and while under general anaesthesia with optimal lung inflation. The vertebral heart scale was measured in all radiographs. RESULTS: The mean (sd) vertebral heart scale in the beagle dogs was 10.3 (0.4) v, showing a significant difference from the mean vertebral heart scale of 9.7 (0.5) v in Buchanan's original study with dogs of different breeds. Degree of inspiration had no significant effect on the vertebral heart scale. CLINICAL SIGNIFICANCE: The vertebral heart scale provides the veterinarian with a possible way of objectively evaluating canine heart size without having to rely on echocardiography. However, the results should be interpreted critically and breed-specific differences should be taken into account, especially with values slightly above the reference range.     

Filaroides hirthi in a British bred beagle dog

Filaroides hirthi was identified in large numbers in the lungs of a British bred beagle dog that had received 10 monthly intra-articular injections of a corticosteroid. The dog was terminally hyperpnoeic and eosinophil and reticulocyte counts were raised. At autopsy, the lungs failed to collapse and minute black and red foci were found throughout the lung parenchyma. These foci were identified histologically as parasites and focal haemorrhage. Migrating larvae were found in the liver and mesenteric lymph nodes. F hirthi has not previously been definitively identified in British dogs and the principal features of its identification and control are discussed.     

Erythrocyte pyruvate kinase deficiency in a beagle dog

A macrocytic hypochromic anemia with marked reticulocytosis was observed at each of 10 examinations during a 4 month period of a male Beagle dog that was 11 months old when first examined. The owner had noticed pale mucous membranes from the time the dog was purchased at 7 weeks of age. Based on the clinical history and negative LE, ANA and Coombs tests, an intrinsic erythrocyte defect was suspected. Erythrocyte osmotic fragility and hemoglobin electrophoresis were normal. Autohemolysis of incubated erythrocytes was marked. Hemolysis was uncorrected by glucose but partially corrected by ATP. With the exception of pyruvate kinase (PK), all of the erythrocyte enzymes measured had greater activities than those of control Beagle erythrocytes. In comparison to moderately reticulocyte-rich controls. PK activity was low in the affected Beagle. Erythrocyte phosphoenolpyruvate content was increased significantly as expected in PK deficiency. The kinetic constant (Km) for phosphoenolpyruvate was lower than that of normal control dogs, a finding in agreement with studies of PK from deficient Basenjis. On these bases a diagnosis of PK deficiency was made.     

Age-related changes in the prostate and testes of the beagle dog.

Age-related changes in the histologic morphology of the Beagle dog prostate have been used as a model for similar changes that occur in human beings. Previous studies of the aging changes in Beagle dogs have been limited to animals less than 10 years of age. In this study, the prostate, testes, and serum testosterone levels were evaluated in healthy Beagle dogs that were grouped by age to provide five groups of dogs that ranged from 3 to 14 years of age. Tissue sections from the prostate and testes were examined qualitatively and quantitatively by light microscopy. All animals 6 years of age and older had histologic characteristics of complex benign prostatic hyperplasia. A mean statistically significant increase in prostatic weight with increased age was noted (mean value 1.08 +/- 0.22 g/kg body weight at 3 years of age, increasing to 2.64 +/- 0.37 g/kg body weight at 14 years of age). Morphometric analysis of the prostatic tissue suggested that similar to the change observed in human males, the increase in size was primarily due to an increase in the absolute volume of interstitial tissues (mean value 2.8 +/- 1.1 cm3 at 3 years of age, increasing to 7.4 +/- 1.3 cm3 at 14 years of age). The epithelial component did not contribute to the increase noted, with the exception that the percentage of glandular lumen did increase with age, indicating progressive cystic dilatation of the glands.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effects of physostigmine on the electroretinogram in the beagle dog

The purpose of the study was to correlate electroretinogram (ERG) parameters with increasing levels of plasma, erythrocyte and ocular tissue cholinesterase inhibition using the beagle dog as a model for human neurovisual toxicity. The anticholinesterase compound physostigmine was administered at various steady-state intravenous infusion rates based on pharmacokinetic estimates of plasma and red blood cell cholinesterase inhibition. The most sensitive parameter was the b-wave amplitude of the rod response, which was significantly depressed compared to pretreatment at all levels of acute cholinesterase depression. The overall maximal ERG response demonstrated a trend of declining a-and b-wave amplitudes, which corresponded with the increased levels of cholinesterase depression, but these differences were not significant. The depression of the electroretinogram rod and cone amplitudes appeared to parallel plasma cholinesterase inhibition more closely than erythrocyte cholinesterase activity. Ocular tissue cholinesterase activity was significantly depressed in the retina (70%), cornea (60%) and dorsal rectus extraocular muscle (46%). Electroretinography may be a useful physiological tool for evaluating the ocular toxicity of certain chemicals or pharmaceuticals associated with cholinesterase biomarker activity.Abbreviations AChE acetylcholinesterase - Amp amplitude - BuChE butyrylcholinesterase - C _p plasma level - C _ss steady-state plasma concentration - D _L loading dose - e ^–kt the rate of elimination over time (t) - ERG electroretinogram - k elimination rate constant - Lat latency - MBW metabolic body weight - O₁–O₅ consecutive oscillatory potential wavelets - PreTx pretreatment - R rate of infusion - R _Inf rate of infusion - V _d volume of distribution     

Pharmacokinetics and bioavailability of dapsone in the beagle dog

The plasma concentration of dapsone (4,4′-diaminodiphenyl-sulphone) was measured after intravenous and oral administration (±5 mg/kg) to female beagle dogs. Analysis of the plasma concentrations showed a bioavailability of the tablet of 99 per cent. The biological half-life in plasma was estimated to be 13±4 hours after intravenous and 11±5 hours after oral application. In order to test the pharmacokinetic models for their validity a chronic experiment was performed with one dog. The plasma curve, predicted from the oral single-dose data, closely matched the measured experimental data points, which indicates that the applied models are likely to be correct.