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in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate related and unrelated Old English Sheepdogs (OESD) by clinical examination, histologic evaluation, and pedigree analysis to determine whether cerebellar degeneration develops in this breed and whether there are genetic implications.

Design—Case study and pedigree analysis.

Animals—24 clinically normal or affected OESD; brain tissue specimens from 25 unaffected or affected OESD.

Procedure—Twenty-four OESD that were chosen because of a family history of gait abnormalities were given physical and neurologic examinations to determine whether they had clinical signs of cerebellar degeneration. Tissue specimens from 25 brains of OESD were examined histologically. Nine OESD that were determined to have cerebellar degeneration histologically as well as 2 clinically affected littermates of the histologically confirmed affected OESD were included in the pedigree analysis. Standard statistical evaluation of pedigrees for hereditary conclusions was used.

Results—Twelve of the 24 OESD evaluated by neurologic examination had a progressive gait abnormality. Clinical signs of cerebellar degeneration typically started later in life in OESD, compared with description for other dog breeds, and progressed ore slowly. Results of pedigree analysis revealed that 11 of 49 dogs were affected in 9 litters, providing an affected-to-total ratio of 22.49%.

Conclusions and Clinical Relevance—Results of our study indicate that a slowly progressing late-onset form of cerebellar degeneration develops in OESD, and the mode of inheritance is by an autosomal recessive gene. (J Am Vet Med Assoc 2000;217:1162–1165)

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in Journal of the American Veterinary Medical Association

Objective

To identify intrinsic, management, nutritional, and environmental risk factors associated with equine motor neuron disease (EMND) and to determine whether epidemiologic evidence supports oxidative stress as a risk factor for developing EMND.

Design

Case-control study.

Animals

87 horses with EMND and 259 control horses.

Procedure

Information concerning each horse’s history of exposure to multiple environmental factors prior to developing EMND was obtained by means of a questionnaire or personal interview. Exposure histories of horses with EMND and control horses were compared, and the association of each risk factor with EMND was evaluated, using logistic regression analysis.

Results

Factors significantly associated with risk of developing EMND included age, breed of horse, duration of residence at the farm, not vaccinating against rabies, and certain feeding practices. Horses that were exercised on green pasture or in grass paddocks were less likely to develop EMND, compared with horses that were exercised in dirt paddocks. Feeding complete pelleted feed as the only source of concentrate or combined with sweet feed was associated with a significant increase in the risk of EMND. Supplementary feeding of vitamin and mineral mixtures not formulated to provide vitamin E or selenium was associated with increased risk of EMND. Horses with a history of cribbing or coprophagia were also at higher risk of developing EMND.

Clinical Implications

Several husbandry practices and intrinsic characteristics of horses appear to modify the risk of EMND. The relationship of specific nutritional factors to EMND supports the hypothesis that a deficiency of vitamin E contributes to the disease. (J Am Vet Med Assoc 1997;211:1261–1267)

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in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine whether equine motor neuron disease (EMND) could be induced in adult horses fed a diet low in vitamin E and high in copper and iron.

Animals—59 healthy adult horses.

Procedure—Horses in the experimental group (n = 8) were confined to a dirt lot and fed a concentrate low in vitamin E and high in iron and copper in addition to free-choice grass hay that had been stored for 1 year. Control horses (n = 51) were fed a concentrate containing National Research Council–recommended amounts of copper, iron, and vitamin E. The hay fed to control horses was the same as that fed to experimental horses, but it had not been subjected to prolonged storage. Control horses had seasonal access to pasture, whereas experimental horses had no access to pasture. Horses that developed clinical signs of EMND were euthanatized along with an age-matched control horse to determine differences in hepatic concentrations of vitamin E, vitamin A, copper, iron, and selenium.

Results—4 experimental horses developed clinical signs of EMND. Plasma concentrations of vitamin E decreased in all 8 experimental horses. There were no significant changes in plasma concentrations of vitamin A, selenium, and copper or serum concentrations of ferritin. There were no significant differences in those analytes between experimental horses with EMND and experimental horses that did not develop EMND. No control horses developed EMND.

Conclusions and Clinical Relevance—Results suggest that lack of access to pasture, dietary deficiency of vitamin E, or excessive dietary copper are likely risk factors for EMND.

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in American Journal of Veterinary Research

Abstract

Objective—To investigate the influence of oxidative stress in terms of antioxidant capacity and lipid peroxidation on the probability of motor neuron disease (MND) in horses.

Animals—88 horses with MND (cases) and 49 controls.

Procedures—Blood samples were collected from all horses enrolled, and RBCs and plasma were harvested. Activity of the enzyme erythrocytic superoxide dismutase 1 (SOD1) was determined in the RBCs. Plasma concentrations of α-tocopherols and β-carotenes and activity of glutathione peroxidase were also evaluated. Degree of lipid peroxidation was measured by determining plasma concentrations of lipid hydroperoxides. Differences were evaluated between horse groups.

Results—Cases had lower erythrocyte SOD1 activity than did controls, but the difference was not significant. On the other hand, plasma vitamin E concentrations differed significantly between groups, with the cases having lower concentrations. Neither plasma vitamin A concentration nor glutathione peroxidase activity differed between groups; however, cases had significantly higher concentrations of lipid hydroperoxides (18.53μM) than did controls (12.35μM).

Conclusions and Clinical Relevance—Horses with MND differed from those without MND by having a lower plasma concentration of vitamin E and higher concentrations of lipid hydroperoxides. Results parallel the findings in humans with sporadic amyotrophic sclerosis and provide evidence supporting the involvement of oxidative stress in the 2 conditions.

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in American Journal of Veterinary Research

Abstract

CASE DESCRIPTION A 5-year-old castrated male Maltese was evaluated for intermittent clinical signs of muscle cramping and abnormal movements of the skin of the right pelvic limb at the site where an infiltrative lipoma had twice been resected. After the second surgery, the surgical field was treated with radiation therapy (RT). The clinical signs developed approximately 14 months after completion of RT.

CLINICAL FINDINGS When clinical signs were present, the right biceps femoris and semitendinosus muscles in the area that received RT were firm and had frequently visible contractions, and the skin overlying those muscles had episodic vermiform movements. Electromyography of those muscles revealed abnormal spontaneous activity with characteristics consistent with myokymic discharges and neuromyotonia. Magnetic resonance imaging of the affected leg revealed no evidence of tumor regrowth. The myokymia and neuromyotonia were considered secondary to RT.

TREATMENT AND OUTCOME 4 U of Clostridium botulinum toxin type A (BoNT-A) neurotoxin complex was injected into the affected muscles at each of 6 sites twice during a 24-hour period (ie, 48 U of BoNT-A were administered). The clinical signs were completely resolved 10 days after BoNT-A treatment and were controlled by repeated BoNT-A treatment every 3 to 4 months for > 1 year.

CLINICAL RELEVANCE To our knowledge, this is the first report of myokymia and neuromyotonia secondary to RT in a dog. For the dog of this report, injection of BoNT-A into the affected muscles was safe, effective, and easy to perform.

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in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association