Although exertional myopathies are commonly recognized in horses, specific etiologies have not been identified. This is the first report in the horse of a deficiency of Complex I respiratory chain enzyme associated with profound exercise intolerance. Physical examination, routine blood tests, endoscopy, and ultrasonograms of the heart and iliac arteries were unremarkable. With slow, incremental exercise (speeds 1.5-7 m/s), the Arabian mare showed a marked lactic acidosis, increased mixed venous PVO2, and little change in oxygen consumption. Muscle biopsies contained large accumulations of mitochondria with bizarre cristae formations. Biochemical analyses revealed a very low activity of the first enzyme complex in the mitochondrial respiratory chain (NADH CoQ reductase). The exercise intolerance and muscle stiffness in this horse were attributed to a profound lactic acidosis resulting from impaired oxidative energy metabolism during exercise.
In vitro genetic transfer of protein synthesis and respiration defects to mitochondrial DNA-less cells with myopathy-patient mitochondria.
Deficiency of skeletal muscle succinate dehydrogenase and aconitase. Pathophysiology of exercise in a novel human muscle oxidative defect
A mutation in the tRNA(Leu)(UUR) gene associated with the MELAS subgroup of mitochondrial encephalomyopathies
Myoclonic epilepsy and ragged-red fiber disease (MERRF) is associated with a mitochondrial DNA tRNA(Lys) mutation
Exercise intolerance, lactic acidosis, and abnormal cardiopulmonary regulation in exercise associated with adult skeletal muscle cytochrome c oxidase deficiency
Fatal infantile cytochrome c oxidase deficiency: decrease of immunologically detectable enzyme in muscle
Oxidative capacity of skeletal muscle fibres in racehorses: histochemical versus biochemical analysis
Familial mitochondrial encephalomyopathy (MERRF): genetic, pathophysiological, and biochemical characterization of a mitochondrial DNA disease
Six unidentified reading frames of human mitochondrial DNA encode components of the respiratory-chain NADH dehydrogenase
Blood chemistry and skeletal muscle metabolic responses to exercise in horses with recurrent exertional rhabdomyolysis
Myophosphorylase deficiency associated with rhabdomyolysis and exercise intolerance in 6 related Charolais cattle
Skeletal muscle metabolic response to exercise in horses with 'tying-up' due to polysaccharide storage myopathy
Histopathologic findings in the sacrocaudalis dorsalis medialis muscle of horses with vitamin E-responsive muscle atrophy and weakness
Equine metabolic myopathies with emphasis on the diagnostic approach. Comparison with human myopathies. A review
Mitochondrial metabolism impairment in muscle fibres of rats chronically intoxicated with Senna occidentalis seeds
Determination of muscle mitochondrial respiratory capacity in Standardbred racehorses as an aid to predicting exertional rhabdomyolysis
Morphological alterations in oxidative muscles and mitochondrial structure associated with equine atypical myopathy
Altered mitochondrial oxidative phosphorylation capacity in horses suffering from polysaccharide storage myopathy
Aneurysms are outward distensions or bulges that occurs in a weakened wall of blood vessels. Discover the latest research on aneurysms here.