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Biomedical subjects

V Dubowitz

Publications and source records attributed to V Dubowitz.

At least 361 records · Page 20Linked to original sources
PubMed1967

Cross-innervated mammalian skeletal muscle: histochemical, physiological and biochemical observations.

1. Cross-innervation of the slow soleus and fast flexor hallucis longus or flexor digitorum longus muscles has been performed in new-born kittens and rabbits and in adult cats.2. The effects on the histochemical and structural properties of the muscle have been studied and compared with the changes in the contractile properties.3. Cross-innervation has produced a dramatic change in histochemical pattern in the fast muscles, with the development of areas of muscle fibres indistinguishable from normal soleus muscle. The converse change from the histochemical pattern of slow soleus to that of fast muscle has also occurred, but has been less consistent.4. It is concluded that the neural influence determining the contractile properties of fast and slow muscle also has a profound controlling influence on the structure and metabolic activity of the muscle fibres.5. No significant changes could be demonstrated biochemically in the ATPase activities of the fast and slow muscles following cross-innervation.

Journal Article↗
PubMedDate not supplied

Measurement of quadriceps muscle thickness and subcutaneous tissue thickness in normal children by real-time ultrasound imaging.

A reproducible ultrasound imaging technique is described for measurement of midthigh muscle and subcutaneous tissue thickness. We studied 276 children including those attending hospital outpatient clinics with non-neurological disorders, newborn babies on the obstetric wards, and children attending a local primary school. There was no significant difference in muscle depth between girls and boys, but girls had a significantly greater subcutaneous tissue depth than boys. The results of this study provide a basis for the study of muscle atrophy and hypertrophy in neuromuscular disease.

Child↗
PubMedDate not supplied

Assessment of quadriceps femoris muscle atrophy and hypertrophy in neuromuscular disease in children.

Midthigh muscle and subcutaneous tissue thickness were measured using a real-time linear array ultrasound scanner in 50 patients attending our Muscle Clinic; 28 had muscular dystrophy and 21 spinal muscular atrophy. In muscular dystrophy the muscle thickness was found to be normal or increased, whereas in spinal muscular atrophy it was reduced, with an associated increase in subcutaneous tissue thickness that did not relate to obesity. Measurement of muscle and subcutaneous tissue thickness provides a more accurate way of assessing muscle atrophy and hypertrophy than clinical assessment, and is a useful guide in the discrimination between muscular dystrophy and spinal muscular atrophy.

Atrophy↗
PubMedDate not supplied

Hypoxanthine-guanine phosphoribosyltransferase activity of blood and muscle in Duchenne dystrophy.

Hypoxanthine-guanine phosphoribosyltransferase (HGPRT) activity was measured in red cells and in skeletal muscles of normal and Duchenne subjects. [8-14C] hypoxanthine was used as substrate, and 5-phospho-alpha-D-ribose 1-diphosphate (PRPP) was used as the ribose-5-phosphate donor. The [8-14C] inosine monophosphate (IMP) formed was separated by high-voltage electrophoresis, and radioactivity was measured by lipid scintillation counting. HGPRT activity in Duchenne and normal red-cell hemolysates was similar, but such activity was significantly higher in Duchenne than in normal muscle homogenates. Red cells of both normal and Duchenne subjects had significantly higher enzyme activity than did skeletal muscles. It is suggested that increased HGPRT activity may be involved in enhancing protein synthesis by increasing intracellular levels of purine ribonucleotides.

Adolescent↗
PubMedDate not supplied

Chloroquine-induced cytosomes with curvilinear profiles in muscle.

A patient with systemic lupus erythematosus (SLE) was treated with chloroquine therapy for four years after the onset of her illness. Nine years after cessation of chloroquine, muscle weakness developed as part of the SLE. Four muscle biopsies performed for diagnostic purposes revealed varying degrees of inflammatory change as well as distinctive cytosomes with curvilinear profiles (CCPs). These CCPs were identical to those reported in Batten disease, a degenerative disorder of children which has a clinical course different from SLE. The CCPs seen in this case of SLE are thought to result from the effect of chloroquine on membrane systems within muscle cells. This report calls attention to the fact that CCPs are not unique to Batten disease bu may also occur in muscle of SLE patients treated with chloroquine.

Adult↗
PubMedDate not supplied

Polymyositis--an immunofluorescence study on the distribution of collagen types.

Type-specific antibodies to the polymorphic types of collagen have been used to study their distribution in polymyositis. Dramatic increases were observed in the staining with antibodies to Type III collagen and, to a lesser extent, with antibodies to Types I, IV, and V. The changes in capillary and endomysial basement membrane collagens (Types IV and V) as well as the proliferation of perimysial Type III collagen are discussed in relation to the muscle atrophy observed during the disease.

Adolescent↗
PubMedDate not supplied

Element analysis of skeletal muscle in Duchenne muscular dystrophy using x-ray fluorescence spectrometry.

Concentrations of calcium, iron, copper, and zinc were simultaneously measured by x-ray fluorescence spectrometry in muscle biopsies from 11 normal subjects, 13 patients with Duchenne muscular dystrophy (DMD), and 3 DMD carriers. Calcium and copper levels were significantly elevated in patients with DMD compared to controls, and one presumptive carrier also showed an elevated calcium concentration. Comparisons with morphological data for the same samples showed a significant positive correlation between calcium concentration and the percentage area of type 2 fibers in controls, but no other correlations were found to be significant. These results illustrate the value of x-ray fluorescence spectrometry and provide further evidence for the involvement of calcium in dystrophic processes.

Adolescent↗
PubMedDate not supplied

Dominantly inherited peroneal muscular atrophy (hereditary motor and sensory neuropathy type I) in infancy and childhood.

A detailed clinical and electrodiagnostic study has been undertaken of demyelinating polyneuropathy in 14 children (9 male, 5 female) from 11 sibships and their parents. The onset of symptoms was before the age of 2 years in 12 of the 14 children, and the condition in all cases was nonprogressive or very slowly progressive. In each case one of the parents had a slow motor nerve conduction velocity. Five of the 11 affected parents were completely asymptomatic. Electrodiagnostic studies in both parents of all children with demyelinating peripheral neuropathy are thus important to identify the dominantly inherited form of the disease.

Adult↗
PubMedDate not supplied

Rotation-mediated aggregation of skin fibroblasts in Duchenne muscular dystrophy. Effects of monensin.

Rotation-mediated aggregation of human skin fibroblasts has been studied and the patterns of aggregation compared between cultures obtained from 9 patients with Duchenne muscular dystrophy and from 10 normal controls. The rate of aggregation was dependent on the growth state of the cells, with growing cells aggregating more rapidly than growth-arrested cells. There was considerable variation between individuals in the rate at which cells aggregated but no differences were detected in the aggregation of normal and DMD cells measured by this method. The monovalent cation ionophore monensin, which inhibits the transport of cellular proteins to the extracellular medium, reduced aggregation of all cells. The data suggest that after initial cell-cell contact continued aggregation is dependent on the secretion of materials to the cell surface. The aggregation of normal and DMD cells was affected similarly by this treatment.

Adolescent↗