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I K Passmore

Publications and source records attributed to I K Passmore.

6 recordsLinked to original sources
PubMed1989

Ultrastructural changes in skeletal muscle in ovine muscular dystrophy.

The initial ultrastructural changes in skeletal myofibers in ovine muscular dystrophy (MD) consisted of focal degeneration of myofibrils and the formation of Z-disc abnormalities, including nemaline rods, in adjacent sarcomeres. Peripheral and central sarcoplasmic masses, which occurred initially in large diameter fibers, contained a mixture of normal organelles and abnormal tubular and fibrillar formations. Vesiculate sarcolemmal nuclei with prominent nucleoli accumulated in central and subsarcolemmal locations in small clusters and short rows. Deformed individual nuclei were sometimes present within nuclear rows. Loss of the myofibrillar mass, increased density of small spherical nuclei, collections of fibrillar and tubular arrays, excessive folding of the sarcolemma and greatly reduced fiber diameter were seen in the end stage of the dystrophic process. Resting satellite cells were present at all stages of lesion development. The morphological progression of the lesions suggested an inherited inability to effectively replace lost myofibrils with ultimate exhaustion of the capacity for repair followed by pathological fiber atrophy.

Animals↗
PubMed1988

Skeletal muscle pathology in ovine congenital progressive muscular dystrophy. 1. Histopathology and histochemistry.

The histopathological lesions of ovine congenital progressive muscular dystrophy (CPMD) were characterized by myofiber hypertrophy, focal myofibrillar degeneration, formation of peripheral and central sarcoplasmic masses devoid of myofibrils and internal nuclei often in chains. Progressive loss of myofibrils was associated with atrophy of the fiber and eventual collapse of the sarcolemma. The process was polyphasic, consequently in mature lesions there was great variation in fiber diameter. Split fibers were common but ring fibers occurred rarely. Myofiber loss was associated with fatty or fibrous tissue replacement. Only type I (red, slow twitch, oxidative) fibers were affected and there was no histological evidence of effective regeneration. Ovine CPMD has many histopathological features in common with dystrophia myotonica in humans.

Adenosine Triphosphatases↗
PubMed1988

Skeletal muscle pathology in ovine congenital progressive muscular dystrophy. 2. Myofiber morphometry.

Fiber-type proportions were determined in 12 skeletal muscles (peronaeus tertius, tibialis cranialis, tensor fascia lata, psoas major, extensor digitorum lateralis, tensor fascia antibrachii, vastus intermedius, soleus, anconaeus, and flexor digitorum superficialis of fore and hind limb) from infantile (20 weeks), juvenile (16 months) and adult (2.5 and 3.5 years) Merino sheep with ovine congenital progressive muscular dystrophy and in age-matched controls. Although confined to type I fibers, lesions were severe not only in type I fiber dominant muscles (vastus intermedius, soleus and anconaeus) but also in the type II dominant medial triceps brachii and in the superficial digital flexors which had approximately equal proportions of both fiber types. The frequency distribution curves of myofiber diameter in dystrophic anconaeus and superficial digital flexor of the fore limb altered as the disease progressed. In young sheep (20 weeks) type I fibers increased in size, then in juvenile and adult sheep the curves became flatter and broader and lost symmetry due to the presence of hypertrophic and atrophic fibers. The fiber diameter profiles were similar to those seen in Duchenne dystrophy in humans.

Animals↗
PubMed1986

Ovine congenital progressive muscular dystrophy: clinical syndrome and distribution of lesions.

The distribution and severity of lesions in the skeletal muscles of 37 Merino sheep with congenital progressive muscular dystrophy (CPMD) are described. An explanation for the clinical signs is offered on the basis of functional defects in regional muscle groups. Lesions in the extensors of the hip, stifle and hock joints and flexors of the digits are primarily responsible for the progressive abnormality of hind limb gait that is characteristic of the clinical syndrome. Lesions in extensors of the elbow and flexors of the shoulder, carpus and digits affected fore limb function in advanced cases. The tendency for some affected sheep to develop ruminal tympany is probably caused by lesions in the diaphragmatic crus. Clinically affected sheep had higher resting and post-exercise concentrations of serum creatine phosphokinase and lactic dehydrogenase than unaffected control sheep. The rise in serum creatine phosphokinase after exercise was greater in affected sheep than in controls. Myotonia was not demonstrated in electromyographic studies in one sheep.

Animals↗