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Biomedical subjects

V Dubowitz

Publications and source records attributed to V Dubowitz.

At least 271 records · Page 15Linked to original sources
PubMed1978

Hypoxanthine--guanine phosphoribosyltransferase activity in blood and skeletal muscles of normal and dystrophic mice.

1. Hypoxanthine--guanine phosphoribosyltransferase (HGPRT) activity was measured in erythrocyte haemolysates and quadriceps muscle extracts of normal and dystrophic 129 ReJ and C57 BL/6J mice with [8(-14)C]hypoxanthine as substrate and 5-phosphorylribose 1-pyrophosphate as a ribose 5-phosphate donor. [8(-14)C]Inosine monophosphate formed was separated by high-voltage electrophoresis and radioactivity was measured by liquid-scintillation counting. 2. In erythrocyte haemolysates, HGPRT activity was similar in normal and dystrophic C57 BL/6J mice but was significantly higher in dystrophic than in normal 129 ReJ mice. Elevated enzyme activity was observed only in mice that were clinically severely affected. 3. In muscle homogenates, HGPRT activity was significantly higher in dystrophic than in normal animals of both 129 ReJ and C57 BL/6J mice. Enzyme activity was not related to the severity of the disease. 4. It is suggested that changes in erythrocytes are secondary to the dystrophic process and that elevated HGPRT activity in skeletal muscle may be related to abnormal energy metabolism, possibly via the pentose monophosphate shunt.

Animals↗
PubMed1978

Tests of skeletal muscle function in children.

The contractile properties of a large proximal muscle (quadriceps femoris) and a small distal muscle (adductor pollicis) have been measured in normal children and children with neuromuscular disorders. The method of stimulating the quadriceps femoris to contract, previously evaluated in adults, was found to be acceptable to children. In normal children a number of indices of muscle function were found to be similar to those in adults. A small study of the function of the adductor pollicis using supramaximal stimulation of the ulnar nerve was carried out in boys with Duchenne dystrophy. Decreased contractile force and prolonged relaxation times from a tetanic stimulation were noted in both the proximal and distal muscles of the boys with Duchenne dystrophy.

Adolescent↗
PubMed1977

Electron-microscopic X-ray microanalysis of normal and diseased human muscle.

Electron-microscopic X-ray microanalysis has been used to compare elemental concentrations in specific organelles in normal and diseased human muscle. An elevated calcium to phosphorus ratio has been found in both myonuclei and interstitial cell nuclei in diseased muscle compared with controls. Preliminary observations also suggest that differences in elemental concentrations may be associated with structural abnormalities such as internal nuclei, and loss of myofibrils.

Adolescent↗
PubMed1977

Comparison of gamma-glutamyl transpeptidase activity in tissues of normal and dystrophic hamsters and mice.

The activity of gamma-glutamyl transpeptidase (gamma-GT), a membrane-bound enzyme, was assayed by a sensitive fluorometric method in the brain, heart, kidney, liver, skeletal muscle and serum of normal and dystrophic hamsters and mice. Normal and dystrophic hamsters were of the golden brown and BIO 14.6 line respectively. Both normal and dystrophic mice were of the C57 BL/6J -dy2j strain. Kidneys of both hamsters and mice contained the highest enzyme activity followed by the brain, skeletal muscle, liver and heart. Gamma-GT activity was elevated in dystrophic skeletal muscles but decreased in the dystrophic kidneys and sera. In the brain, heart and liver of dystrophic animals from both species enzyme activity was similar to that in normals.

Animals↗
PubMed1977

Concomitance of basophilia, ribonucleic acid and acid phosphatase activity in regenerating muscle fibres.

Regenerating fibres from tibialis anterior muscles of mice and hamsters transplanted as minced fragments for 7 and 9 days respectively were compared for basophilia, ribonucleic acid (RNA) and acid phosphatase activity with fibres in muscles of patients with Duchenne muscular dystrophy, limb--girdle dystrophy and dermatomyositis. Normal muscles of mice, hamsters and humans were used as controls. In normal muscle fibres basophilia and RNA activity were restricted to the nuclei and acid phosphatase activity was occasionally observed in the nuclei, endomysial connective tissue and around muscle spindles. Diseased human muscle fibres were rich in acid phosphatase activity, the enzyme being most prominent in degenerating and basophilic fibres. When examined in serial sections, all basophilic fibres showed RNA and acid phosphatase activity. Similarly, all regenerating fibres in minced transplants which were basophilic to haematoxylin contained high RNA and acid phosphatase activity. It is suggested that basophilia in diseased human muscle fibres represents regeneration and that the lysosomes, as defined by acid phosphatase activity in these fibres, may be promoting their growth and differentiation by facilitating greater nucleocytoplasmic communication which ultimately could lead to protein synthesis.

Acid Phosphatase↗
PubMed1977

Correlation of single fibre EMG and muscle histochrmistry using an open biopsy recording technique.

Single fibre electromyographic (SFEMG) recordings were carried out during open muscle biopsy. Nine patients were studied, including 5 with Duchenne muscular dystrophy, 2 with spinal muscular atrophy and 1 each with limb-girdle dystrophy and myotonic dystrophy. Correlations were possible between the SFEMG fibre density determinations and histochemical evidence of grouping in some biopsies, particularly involving Type I fibres. This combined technique permits an improved assessment of the functional state of abnormal muscle.

Adolescent↗
PubMed1977

Effect of pentobarbitone sodium on serum creatine kinase of normal and dystrophic hamsters.

1. The dose of pentobarbitone required for anaesthesia was significantly greater for dystrophic hamsters than for normal animals. 2. Serum creatine kinase activity was significantly higher in dystrophic than in normal hamsters. 3. Brain, heart and tibialis anterior muscle from dystrophic animals contained significantly less creatine kinase than the normal tissues. 4. Creatine kinase in normal and dystrophic sera, as in skeletal muscles, consisted of MM isoenzyme. Heart creatine kinase consisted of both MM and MB types and brain contained only the BB isoenzyme. 5. Pentobarbitone raised serum creatine kinase activity of normal and dystrophic hamsters to the same extent, elevation of enzyme activity being dependent on the amount of pentobarbitone injected. 6. The sera of pentobarbitone-treated normal and dystrophic hamsters contained only the MM isoenzyme.

Animals↗