DYSTROPHY-LIKE MYOPATHY IN A FOAL

Two muscle biopsies from the gluteus medius and semitendinosus muscles of a six-month-old male standardbred trotter with clinical signs of h ypertrophy and hypertonicity, and an electromyogram showing myotonic d ischarges in the glutei, semitendinosus and semimembranosus muscles, w ere examined by histological, histochemical and ultrastructural method s. Histologically, the main findings were variations in fibre size and shape, vacuolisation, hyalinisation and the splitting of fibres, an i ncrease in the numbers of internal nuclei, infiltration by connective tissue and fat, hypertrophy and the predominance of type I fibres, and clusters of one type of fibre. These histological results resembled t hose in human muscular dystrophy.