Peripheral hypomyelinization in two golden retriever littermates

Peripheral hypomyelinization was found in 2 Golden Retriever littermates that had pelvic limb ataxia, depressed postural reactions, and depressed segmental reflexes. Diagnostic findings included infrequent denervation potentials, reduced or absent evoked potentials, and markedly diminished motor nerve conduction velocities. Light and electron microscopy of peripheral nerves revealed fewer than normal myelinated axons, myelinated sheaths inappropriately thin for the caliber of the fiber, poor myelin compaction, greater than normal numbers of Schwann cell nuclei, many Schwann cells with voluminous cytoplasm, and greater than normal amount of perineural collagen. Findings were compatible with a peripheral hypomyelinization process; a defect in Schwann cell function was suspected.     

Congenital hypomyelinating polyneuropathy in two golden retriever littermates

Serial peripheral nerve biopsies from two golden retriever littermates with chronic neurologic disease were taken for morphologic and morphometric evaluation. Teased nerve preparations were difficult to interpret due to the lightness of myelin staining. Light and electron microscopic findings were characterized by the following: reduced number of myelinated axons, presence of myelinated sheaths inappropriately thin for the caliber of the fiber, poor myelin compaction, increased numbers of Schwann cell nuclei, increased concentration of neurofilaments in myelinated axons, many Schwann cells with voluminous cytoplasm, and increased perineurial collagen. Onion bulb formation was not seen. In contrast to control data, a poor correlation was seen between numbers of myelin lamellae (ML) and axonal circumference (AC). The frequency distribution of ML ranged from 5 to 55 lamellae in affected animals (mean, 28 lamellae) compared to 20 to 140 lamellae in controls (mean, 66 lamellae). The ML/AC ratio was significantly reduced (P less than 0.001) in nerves of affected dogs. Morphometric results indicated that fibers of all calibers were hypomyelinated.     

Electrodiagnostic evaluation in feline hypertrophic muscular dystrophy

Standard needle electromyography (EMG) of 56 muscles and nerve conduction velocities (NCV) of the ulnar and common peroneal nerves were investigated in each of six cats affected with hypertrophic feline muscular dystrophy, 10 related heterozygote carriers and 10 normal cats. The EMG findings were considered normal in carrier and control cats, and consisted of 33% normal readings, 22% myotonic discharges, 18% fibrillation potentials, 11% prolonged insertional potentials, 10% complex repetitive discharges and 6% positive sharp waves in affected cats. Muscles of the proximal limbs were most frequently affected. No differences in NCV were found between the three cat groups. It was concluded that dystrophin-deficient dystrophic cats have widespread and frequent EMG changes, predominantly myotonic discharges and fibrillation potentials, which are most pronounced in the proximal appendicular muscles.     

Atypical pectus excavatum in two Welsh terrier littermates

Two six-week-old intact Welsh terrier littermates, a male and a female, were presented for congenital ventral thoracic wall deformities characterised by noticeable funnel-like depressions of the cranial sternum associated with inversion of the rib cage. No exercise intolerance or cardiac murmurs were noted. Thoracic radiographic examination revealed a significant dorsal deviation of the first to the fifth sternebrae. At 12 weeks of age, the thoracic depressions had improved markedly in both puppies. Thoracic radiography to reassess the sternal deviation was at this stage within normal limits, demonstrating complete radiographic resolution of the sternal deformity.     

Observations on exocrine pancreatic insufficiency in a family of English setter dogs

The aim of this paper is to report serum trypsin-like immunoreactivity (TLI) concentrations in the progeny of a pair of English setters. These dogs had a history of producing puppies with a high prevalence of exocrine pancreatic insufficiency (EPI) secondary to either congenital deficiency or early onset juvenile atrophy of pancreatic acinar cells. Serum TLI concentrations in the clinically healthy parents of the puppies with EPI were normal, as were serum TLI concentrations in the unaffected puppies. However, serum TLI concentrations were extremely low (less than 1 μg/litre) in three puppies at eight to 12 weeks of age when clinical signs of EPI were present. In addition, one of the three puppies, with low TLI concentrations at eight weeks of age, had serum TLI concentrations of 0.7 μg/litre at two weeks of age even though no clinical signs were evident at that time. These results suggest that serum TLI assay may be a useful diagnostic aid in identifying puppies at a very early age with this unusual form of EPI.     

Electrodiagnostic evaluation of peripheral nerve function in rheas and barred owls

OBJECTIVE: To establish reference values for electrodiagnostic evaluation of peripheral nerve function in birds. ANIMALS: 6 rheas and 6 barred owls. PROCEDURE: Birds were anesthetized with propofol or isoflurane in oxygen. Using a computer-based electromyograph system and needle electrodes for stimulation and recording, electromyography (EMG) was performed on the pectoral, biceps brachialis, and gastrocnemius muscles, and evoked EMG was performed on the tibial and ulnar nerves. Motor nerve conduction velocity (MNCV) was calculated. Repetitive stimulation was performed on these 2 nerves. Late F waves were recorded for each nerve, when possible. RESULTS: Activity was evident during insertion of the electrodes, but muscles tested were electrically quiescent after spontaneous EMG. Motor nerve conduction velocity was faster in the tibial nerve than ulnar nerve but did not differ significantly between species. Mean +/- SEM MNCV was 132.3+/-7.8 m/s for the tibial nerve and 59.7+/-7.8 m/s for the ulnar nerve. A significant difference was not observed in responses at the fourth or ninth stimulation during repetitive stimulation. Subsequent to the initial stimulation, amplitudes were +/-22.7% of the initial motor potential amplitude. Recorded F waves were inconsistent, which may have been associated with technique. CONCLUSIONS AND CLINICAL RELEVANCE: Reference range (mean +/-2 SEM) for MNCV was 34.1 to 75.3 m/s for the ulnar nerve and 116.7 to 147.9 m/s for the tibial nerve in barred owls and rheas. After repetitive stimulation, motor potential amplitudes may be +/-22.7% of the initial amplitude response.     

Hypochondroplastic dwarfism in the Irish setter

Two test matings in the Irish setter were performed, and genetic, clinical, morphometric, radiographic, bone histological and plasma and urine biochemical features of dwarfism were studied. All offspring were phenotypically normal at birth and weaning, but at the age of 2–5 to 4 months the longitudinal growth of the spine and leg bones was retarded in the dwarfs compared with the normal littermates. Most dwarfs performed well, even in the field. Radiographic and histological evaluations revealed a hypochondroplasia. A morphometric diagnostic method for Irish setter dwarfism was developed. A single autosomal recessive mode of inheritance was verified.     

Episodic weakness associated with exertional lactic acidosis and myopathy in Old English sheepdog littermates.

Two Old English Sheepdog littermates were evaluated for weakness that developed during periods of minimally intense exercise. Lactic acidosis accompanied by increased muscle enzyme activity, an increased lactate/pyruvate ratio, and increased venous PO2 supported the possibility of defective mitochondrial oxygen use. Electromyographic abnormalities included increased insertional activity and complex repetitive discharges. Muscle alterations included scattered myofiber necrosis, abundant endomysial connective tissue, excessive glycogen accumulation, and greater than normal numbers and vacuolation of mitochondria. A distinctive pattern of subsarcolemmal mitochondrial aggregates, referred to as "ragged red fibers" in human mitochondrial myopathies, was observed in muscle biopsy samples from 1 dog. Several features of the disease in these dogs, including onset of weakness during early life, simultaneous disease in littermates, subtle nonprogressive weakness of at least 3 years' duration, and partial reversibility of lactic acidosis following rest were suggestive of an inborn error of metabolism, consistent with mitochondrial myopathy.     

Lumbar spinal 'juxtaarticular' cyst in a Gordon setter

An 11-year-old Gordon setter bitch was presented with a history of progressive weakness in the right hind limb associated with pain in the lumbar spine. Neurological deficits consisted of ataxia, monoparesis, muscle atrophy and spontaneous over-knuckling of the affected limb. A large 'juxtaarticular' cyst located in a right dorsolateral position of the intervertebral foramen at L3-L4 was diagnosed by magnetic resonance imaging. The cyst was removed through a modified laminectomy. The dog recovered quickly and returned to the owners 4 days after surgery with slight neurological symptoms. During the follow-up examination 2 and 6 months later, the Setter showed normal gait and neurological examination.     

Risk factors for gastric dilatation in Irish setter dogs

Questionnaires were used to obtain data about Irish setters with gastric dilatation (GD) and control Irish setters. The risk of GD increased with age (P<0·01) but was not associated with gender. Age and gender-matched controls were compared with cases (n=74). Predisposing risks were aerophagia (unadjusted odds ratio 12·44, P<0·001), a single food type (adjusted odds ratio 3·15, P<0·01) and feeding once daily (adjusted odds ratio 2·90, P<0·02). Apparent risk from a dry food diet and a condition score of less than 2 was not confirmed by logistic regression. Precipitating risks were recent kennelling (unadjusted odds ratio 100, P<0·005) or a car journey (unadjusted odds ratio 3·29, P<0·025). No risk was attributed to intensity or duration of exercise, temperament, appetite, speed of eating, vomiting or diarrhoea.     

Congenital dilatation of the large and segmental intrahepatic bile ducts (Caroli's disease) in two Golden retriever littermates

Two, sibling, male Golden retriever puppies, 13 weeks of age, were presented with congenital biliary cysts of the liver involving both hepatic and segmental bile ducts, as well as bilateral polycystic kidney disease. Ultrasonography of the livers of both pups demonstrated segmental cystic lesions that were contiguous with the bile ducts. Histopathology revealed cystic ectatic bile duct hyperplasia and dysplasia with variable portal fibrosis in the liver, while in the kidneys there were radially arranged, cylindrically dilated cysts of the collecting ducts, which extended through the medulla and cortex. This pathology was compatible with that of congenital dilatation of the large and segmental bile ducts (Caroli's disease) described in humans, dogs and rats. In humans Caroli's disease has an autosomal recessive inheritance pattern, while in rats activation of the MEK5/ERK cascade initiates the biliary dysgenesis of Caroli's disease in this species. However, the exact mode of inheritance and pathogenesis of Caroli's disease in dogs is as yet unknown. Previous reports on congenital hepatic cystic diseases of the dog have described Caroli's disease like lesions in various breeds, but these are believed to be the 1st reported cases in the Golden retriever breed.     

Leucocyte adhesion protein deficiency in Irish setter dogs.

Investigation of 12 Irish setter puppies from six litters with severe recurrent infections, neutrophilia and low body weight revealed a leucocyte adhesion protein deficiency with a total lack of CD11b and CD18. Their neutrophil function was severely impaired with a totally absent capacity to ingest C3b-opsonized particles, a significantly impaired capacity to ingest IgG-opsonized particles and significantly diminished adherence to nylon wool when compared with neutrophils from healthy control dogs. The chemiluminescence of patient neutrophils activated by C3b-opsonized particles was, consequently, significantly decreased compared with that of control neutrophils, while the respiratory burst assayed by phorbolmyristate acid (PMA) stimulated nitroblue tetrazolium (NBT)-reduction was normal in the patient group. Random migration and chemotactic responses of patient and control neutrophils, were similar. The etiology, pathogenesis and clinical manifestations of the Irish setter leucocyte adhesion deficiency were similar to that of the leucocyte adhesion deficiency in humans.     

Idiopathic chylothorax and lymphedema in 2 whippet littermates

Idiopathic chylothorax and limb edema was diagnosed in two 2-year-old male whippet siblings. The fact that the 2 related animals developed similar clinical signs at a young age may suggest a congenital or hereditary etiology.     

Delayed growth in two German shepherd dog littermates with normal serum concentrations of growth hormone, thyroxine, and cortisol

Four German Shepherd Dogs from a litter of 10 were evaluated because of postnatal onset of proportionate growth stunting that clinically resembled well-documented hypopituitary dwarfism in that breed. Although 2 pups had histologic evidence of hypopituitarism, the remaining 2 pups had normal serum growth hormone concentration and adrenocorticotropin secretory capability, and normal adrenal function test and thyroid function study results. Furthermore, the initially stunted German Shepherd Dogs grew at a steady rate until at 1 year, body weight and shoulder height approximated normal measurements. Seemingly, delayed growth in these pups may represent one end of a clinical spectrum associated with hypopituitarism in German Shepherd Dogs.     

Esophageal obstruction caused by a left aortic arch and an anomalous right patent ductus arteriosus in two German Shepherd littermates

OBJECTIVE: To present details of surgical management of an unusual vascular ring anomaly in two German Shepherd littermates. STUDY DESIGN: Clinical case report. STUDY POPULATION: Three-month-old intact male and female German Shepherd littermates. RESULTS: In each dog, the esophagus was obstructed by a vascular ring comprised of the left aortic arch, an anomalous patent right ductus arteriosus, and the pulmonary artery ventrally. Surgical treatment consisted of dividing and oversewing the patent right ductus arteriosus. Neither dog has clinical signs of esophageal disease one year after treatment. CONCLUSION AND CLINICAL RELEVANCE: This vascular ring anomaly should be considered a possibility in any young dog with esophageal obstruction and a machinery murmur.     

Epitheliotropic lymphoma (mycosis fungoides) presenting as blepharoconjunctivitis in an Irish setter

An 11-year-old neutered female Irish setter was presented with a six-week history of blepharoconjunctivitis affecting the right eye. A conjunctival biopsy was taken and histopathological examination revealed a heavy cellular infiltrate involving the epithelial and subepithelial tissues. Immunohistochemical staining showed the intraepithelial cell population to uniformly have the phenotype CD3 (T-cell specific marker). A diagnosis of epitheliotropic lymphoma (mycosis fungoides) was made. The use of a synthetic retinoid and topical prednisolone in the management of the case is discussed.