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Biomedical subjects

K Braund

Publications and source records attributed to K Braund.

6 recordsLinked to original sources

'Continuous muscle fibre activity' in six dogs with episodic myokymia, stiffness and collapse.

Continuous muscle fibre activity was observed in a crossbred dog, a Yorkshire terrier, a border collie and three Jack Russell terriers. The clinical signs consisted of episodes of generalised myokymia which developed into muscle stiffness and delayed muscle relaxation and generally led to the dogs collapsing into lateral recumbency. These episodes were preceded by intense facial rubbing in three of the dogs, and were associated with severe hyperthermia in five of them. All three Jack Russell terriers showed continuous ataxia. The dogs had above normal activities of aspartate aminotransferase, alanine aminotransferase and creatine kinase, but their cerebrospinal fluid was normal. Myokymic discharges were observed by electromyography in two of the dogs. Two of them were treated with membrane-stabilising agents, with variable results.

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Caffeine contractures, twitch characteristics and the threshold for Ca(2+)-induced Ca2+ release in skeletal muscle from horses with chronic intermittent rhabdomyolysis.

Muscle from horses with intermittent exercise associated rhabdomyolysis was examined to determine if calcium regulation was abnormal. In vitro studies on semimembranosus muscle fibre bundles showed the time to 50 per cent relaxation of caffeine-induced contractures was shorter and the electrically elicited twitch longer in horses with exercise associated rhabdomyolysis. Substitution of strontium for calcium eliminated the difference in caffeine contracture between the normal and rhabdomyolysis horses. The threshold of calcium-induced calcium release was lower than normal in terminal cisternae-containing fractions of muscle from horses with rhabdomyolysis. Thoroughbreds with rhabdomyolysis had a shorter time to peak twitch tension than standardbreds, and normal thoroughbreds had a shorter caffeine contracture than normal standardbreds. There was no difference in fibre typing between breeds or groups. Either no histological changes or low grade to moderate degenerative myopathy was seen in muscle from horses with rhabdomyolysis. These results suggest horses with intermittent exercise associated rhabdomyolysis have abnormal calcium regulation.

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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.

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Lissencephaly in two Lhasa Apso dogs.

Lissencephaly, a congenital absence of cerebrocortical convolutions, was discovered in 2 Lhasa Apso dogs by clinical and pathologic evaluation. Neurologic abnormalities, which became evident within the 1st year of life, included behavioral, visual, and convulsive disorders. The neurologic abnormalities were mild or delayed in onset after birth, indicating the dog is less dependent on the cerebral cortex for sensorimotor function than is man.

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Coccygeal muscle injury in English Pointers (limber tail).

A condition colloquially referred to as "limber tail" and "cold tail" is familiar to people working with hunting dogs, primarily Pointers and Labrador Retrievers. The typical case consists of an adult dog that suddenly develops a flaccid tail. The tail either hangs down from the tail base or is held out horizontally for several inches from the tail base and then hangs straight down or at some degree below horizontal. Initially, the hair on the dorsal aspect of the proximal tail may be raised and dogs may resent palpation of the area 3-4 inches (8-10 cm) from the tail base. Most dogs recover spontaneously within a few days to weeks. Anecdotal reports suggest that anti-inflammatory drugs administered within 24 hours after onset hasten recovery. Less than one half of affected dogs experience a recurrence. Affected Pointers almost always have a history of prolonged cage transport, a hard workout the previous day, or exposure to cold or wet weather Most owners and trainers familiar with the condition do not seek veterinary assistance. In cases where people are not familiar with this disease, other conditions such as a fracture, spinal cord disease, impacted anal glands, or prostatic disease have been incorrectly diagnosed. We examined 4 affected Pointers and found evidence of coccygeal muscle damage, which included mild elevation of creatine kinase early after onset of clinical signs, needle electromyographic examination showing abnormal spontaneous discharges restricted to the coccygeal muscles several days after onset, and histopathologic evidence of muscle fiber damage. Specific muscle groups, namely the laterally positioned intertransversarius ventralis caudalis muscles, were affected most severely. Abnormal findings on thermography and scintigraphy further supported the diagnosis.

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Motor neuron abiotrophy in a saluki.

A nine-week-old saluki puppy was presented to Tufts University School of Veterinary Medicine for progressive, generalized weakness and bilateral forelimb deformities. Examination suggested a diffuse neuromuscular lesion. Cerebrospinal fluid (CSF) analysis showed normal nucleated cell count and protein level; however, many macrophages had vacuolated cytoplasm. Electromyography (EMG) recordings suggested denervation in paraspinal and appendicular muscles. Tibial motor nerve conduction velocity was normal, but direct evoked muscle potential had reduced amplitude. Histopathology revealed diffuse, symmetrical, degenerative motor neuronopathy of the ventral horn of the spinal cord with associated lesions in nerves and muscles. Histopathology was consistent with an abiotrophy that was likely inherited.

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