Genetic aspects of Labrador Retriever myopathy.

Labrador Retriever myopathy (LRM) has become a relatively common muscular disease. The objective of our prospective study was to determine by segregation analyses a plausible mode of inheritance within a Labrador Retriever population. Therefore we performed neurological examinations, as well as electromyographic and histopathological evaluations of 58 closely related dogs. Seven dogs with an average age of 27.8 months had clinical signs consistent with LRM including exercise intolerance or fatigue. The diagnosis was based on neurological deficits and confirmed by histopathological results of muscle biopsy. We found in all cases obvious differences in fiber calibre size associated with texture disturbances. In addition, we found 41 clinically normal dogs with histological findings consistent with LRM. Three genetic models, the major gene, the mixed inheritance as well as the environmental model, were evaluated by segregation analyses. They were applied to an extended pedigree including 164 non-randomly ascertained related Labradors. According to phenotype the clinically examined dogs were divided into two different data sets. One data set distinguished between clinically normal and abnormal dogs, the second data set between histopathologically normal and abnormal dogs. We concluded that the clinical form of LRM is transmitted by a major gene and controlled by an autosomal recessive mode of inheritance. Furthermore, for expression of the subclinical form an additional gene or an environmental factor is responsible. Our findings suggest that LRM is similar to limb-girdle muscular dystrophy in man and therefore, may be used in the future as an animal model.

[Hemorrhagic pericardial effusion in dogs. A retrospective study of 10 cases (1989-1994) with a review of the literature]. / Hämorrhagischer Perikarderguss beim Hund. Eine retrospektive Studie von 10 Fällen (1989-1994) mit Ubersicht der Literatur.

After an introduction on pathophysiological and etiological aspects of idiopathic hemorrhagic pericardial effusion, ten dogs affected with this condition are described. Clinical signs permitted to establish a diagnosis of suspicion in all cases. Electrocardiography, thoracic radiography and echocardiography allowed confirmation of the diagnosis. Echocardiography was the most sensitive method available. Six dogs had idiopathic pericardial effusion. A subtotal pericardectomy was performed in two of these dogs. In four dogs, the effusion was caused by a tumor. Two dogs with mesothelioma were euthanized because of poor prognosis. Heart base tumors were found in the two other dogs. One of them is still alive and well one year after subtotal pericardectomy. The other one was euthanized due to deterioration of his condition two years after the operation. Idiopathic hemorrhagic pericardial effusion carries a good prognosis if appropriately treated (pericardiocentesis, possibly subtotal pericardectomy). Pericardial effusion is also frequently associated with tumors. In such cases, prognosis and therapy essentially depend on the type of tumor.