Search PubMed⌕ Search

Biomedical subjects

V Dubowitz

Publications and source records attributed to V Dubowitz.

At least 253 records · Page 14Linked to original sources
PubMed1981

An X-linked disease of the nervous system with disordered copper metabolism and features differing from Menkes disease.

We studied 2 of 4 affected boys with a new disease associated with abnormalities of copper metabolism. The four cases occurred in two generations of a family. This syndrome was similar to Menkes disease in some respects: X-linked recessive inheritance, marked psychomotor retardation with seizures, low serum copper and ceruloplasmin levels, and a block in gut copper absorption. There were also striking differences from Menkes disease. Patients had normal birthweight at term, no hypothermia, and survived beyond the usual Menkes age group with static neurologic disease including hypotonia and choreoathetosis. In addition, general examination of both children was unremarkable apart from undescended testes and growth retardation. The hair, facies, and skin were normal and there was no radiologic evidence of bony changes. Detailed studies of copper absorption were performed.

Brain Diseases, Metabolic↗
PubMed1980

Protein degradation in skin fibroblasts from patients with Duchenne muscular dystrophy.

The rates of degradation of [3H]leucine-labelled proteins have been measured in cultures of skin fibroblasts obtained from normal controls (five subjects) and patients with Duchenne muscular dystrophy (six subjects). Cultures were incubated with [3H]leucine (10 microCi/ml) for 60 min to label "short-lived" proteins, and with [3H]leucine (5 microCi/ml) for 60 h to label "long-lived" proteins. Optimal wash procedures were devised for removal of [3H]leucine from the extracellular space and from cell pools before beginning degradation measurements. Re-utilization of [3H]leucine released from degraded labelled proteins was prevented by supplementing the medium with 4mM-leucine. Rates of degradation did not depend on the growth state of the cells or on cell age over the range used (passages eight-20). Degradation of long-lived proteins was approximately linear over a 24h period, at a rate of 1.0% per h. 30% of short-lived protein was degraded within 6h. No differences were observed between protein degradation in normal fibroblasts and in those from patients with Duchenne muscular dystrophy.

Adolescent↗
PubMed1980

Detection of pathological change in dystrophic muscle with B-scan ultrasound imaging.

A comparative study of the ultrasound appearances of the thigh with the static B scan showed consistent differences in 10 children with muscular dystrophy compared with 40 healthy controls. This non-invasive technique could be useful in assessing the extent of pathological change in dystrophic patients and could prove a valuable diagnostic aid.

Adolescent↗
PubMed1980

Erythrocyte ghost Na+,K+-adenosine triphosphatase in Duchenne muscular dystrophy.

Erythrocyte ghost membranes have been prepared by two different methods from patients with Duchenne muscular dystrophy (DMD), carriers of DMD, patients with other neuromuscular diseases, and normal individuals. The susceptibility of the membrane Na+,K+-adenosine triphosphatase (ATPase) to the cardiac glycoside, ouabain, has been investigated using various assay conditions. A stimulation of the enzyme has not been detected under any of the conditions employed. Using either a "high salt" (100 mM NaCl, 20 mM KCl) or a "low salt" (1 mM NaCl, 2 mM KCl) assay in the presence of EGTA a reduced susceptibility of the enzyme to ouabain was observed in preparations from patients with DMD compared with those from normal individuals. This behaviour was not manifest in preparations from NAD carriers or from patients with other neuromuscular diseases. The response of the erythrocyte membrane Na+,K+-ATPase activity to changes in temperature has also been investigated. The temperature response of the enzyme from DMD and DMD carrier preparations was indistinguishable from that of normal preparations. In all cases a break in the Arrhenius plot occurred at 21 degrees C.

Adolescent↗
PubMed1980

A new approach to the neurological assessment of the preterm and full-term newborn infant.

A method has been developed for the neurological assessment of the newborn infant comprising a carefully selected series of neurological and neurobehavioral items. It is applicable to preterm as well as full-term infants within 24 hours of birth, and can also be repeated sequentially on the same infant. The whole examination is recorded directly on a single sheet which also contains detailed instructions and diagrams. Individual items are scored on a 5-point scale, but no attempt has been made to compute a single total score, as it was thought more advantageous to document a pattern for individual groups of signs. Pilot studies have already demonstrated its sensitivity to perinatal factors such as drugs, asphyxia and infection. The examination can be rapidly documented by residents with no special training in newborn neurology. This method should provide a practical and objective means of monitoring the neurological status of the newborn infant, and also a baseline for longitudinal studies of neurological function in the newborn and developing infant.

Asphyxia Neonatorum↗
PubMed1980

Visual function in the newborn: a study of preterm and full-term infants.

Visual function has been studied in the preterm newborn infant by the visual orientation (tracking) technique of the Brazelton neurobehavioral assessment, and the pattern preference and fixation technique of Fantz. By both these methods we have been able to document the presence of discriminative visual function by 31-32 weeks gestation, and by 34 weeks the pattern reaches a maturity comparable to the full-term infant. Sequential studies at weekly intervals of preterm infants ranging in gestation from 28-32 weeks showed a similar pattern of development of visual function to the newborn infant of equivalent postconceptional age. Comparative studies of the two methods of assessment of visual function in the same infants have shown surprisingly little correlation. Assessment of visual function in the preterm newborn infant is a valuable milestone and, as in the case of other developmental milestones, aberrations may reflect a deficit in visual function itself, or a more broad based deficit in neurological function or a secondary response to a generalized illness in the newborn infant.

Choice Behavior↗
PubMed1980

Subcellular fractionation studies on hepatic tissue from a patient with Pompe's disease (type II glycogen-storage disease).

1. An homogenate of liver biopsy taken from a patient with Pompe's disease (type II glycogen-storage disease) was analysed by enzyme microassay and subcellular fractionation by sucrose-density-gradient centrifugation. 2. A strikingly low activity of lysosomal acid alpha-D-glucosidase was noted but there was also increased activity of neutral alpha-D-glucosidase (found in endoplasmic reticulum). 3. Activities of the acid hydrolases, acid phosphatase and beta-N-acetyl-D-glucosaminidase, were elevated compared with those of controls. Measurement of latent beta-N-acetyl-D-glucosaminidase activity and results of subcellular fractionation experiments, indicated a marked fragility of certain populations of lysosomes. Lysosomes containing predominantly acid phosphatase and beta-D-glucuronidase activities appeared to have normal integrity. 4. Assessment of organelle pathology by enzyme microassay indicated low mitochondrial and peroxisomal enzyme activities. In addition there was evidence of mitochondrial damage as reflected by increased sucrose permeability and by ultrastructural studies.

Acetylglucosaminidase↗
PubMed1980

Visual function in the preterm and fullterm newborn infant.

Visual function in the preterm newborn infant has been studied by the visual orientation (tracking) technique of the Brazelton neurobehavioural assessment, and by the pattern preference and fixation techniques of Frantz. Both these methods demonstrated the presence of discriminative visual function by 31 to 32 weeks gestation, which by 34 weeks reaches a maturity comparable to the pattern found in fullterm infants. Sequential studies at weekly intervals of preterm infants, ranging in gestation from 28 to 32 weeks, have shown a similar pattern of development of visual function to that of the newborn infant of equivalent postconceptional age. However, comparative studies of visual orientation and pattern preference in the same infants have not shown a close correlation. The assessment of visual function in the preterm newborn infant is a valuable milestone. Aberrations may reflect a dificit in visual function itself, a more broad-based deficit in neurological function, or possibly a response to a generalised illness.

Choice Behavior↗
PubMed1979

Duchenne muscular dystrophy: 45Ca exchange in cultured skin fibroblasts and the effect of calcium ionophore A23187.

Calcium exchange was studied in skin fibroblasts cultured from eight subjects with Duchenne muscular dystrophy, four with Limb Girdle dystrophy and eight normal controls using 45Ca. No difference was found in the time course of calcium exchange between the groups, nor in the level of 45Ca when maximal exchange had occurred. Treatment of the cultures with the calcium ionophore A23187 resulted in higher levels of calcium exchange over a 2-H period. The increase was similar in the cultures from the 3 patient groups studied.

Adolescent↗
PubMed1979

Antenatal diagnosis of Duchenne muscular dystrophy.

As a means of assessing the value of fetal serum-creatine-kinase (S.C.K.) levels in the antenatal diagnosis of Duchenne muscular dystrophy (D.M.D.), fetal muscle from control and at-risk fetuses was studied histologically and the findings were related to fetal S.C.K. levels. Of 7 at-risk fetuses 4 were believed to have normal muscle and all these had normal S.C.K. levels. However, of 3 fetuses with abnormal muscle only 1 had a raised S.C.K. level. At present caution should be exercised in offering antenatal diagnosis in D.M.D. on the basis of fetal S.C.K. levels.

Creatine Kinase↗
PubMed1979

Myonuclear calcium in carriers of Duchenne muscular dystrophy. An X-ray microanalysis study.

Electron-microscopic X-ray microanalysis (EMMA) was used to study calcium and phosphorus concentrations in the muscle fibre nuclei of 3 genetically definite, 5 probable and 2 possible carriers of Duchenne muscular dystrophy. All cases showed elevated mean calcium:phosphorus ratios compared with 4 female controls and, with the exception of one possible carrier, all showed elevated calcium concentrations. A significantly greater variation of values was also found for both parameters. Analyses were made of nuclei from fibres showing no morphological abnormalities and the results suggest elevation of myonuclear calcium may be an early defect in dystrophic muscle.

Adolescent↗
PubMed1979

Increased calcium-activated neutral protease activity in muscles of dystrophic hamsters and mice.

A Ca2+-activated neutral protease activity was examined in muscles of normal and dystrophic hamsters and mice. Light grey and golden brown strains of normal and B10 14.6 strain of dystrophic hamsters were used. Normal and dystrophic mice were of the Bar Harbor 129 ReJ strain. Enzyme activity was measured in the post myofibrillar fraction (homogenate) and in the 75,000 x g pellet (particulate fraction) and supernatant using purified myofibrils. In normal and dystrophic hamsters or mice, the Ca2+-activated neutral protease was most active in the supernatant followed by the homogenate and particulate fractions. As compared to fractions from normal muscle, enzyme activity was significantly elevated in all 3 fractions from dystrophic muscles of hamsters and mice. Both homogenate and supernatant fractions from muscles of normal hamsters had significantly higher enzyme activity than those of normal mice. Enzyme activity was similar in the particulate fraction. Similarly enzyme activity in the 3 fractions from dystrophic hamster and mouse muscles showed no significant difference. It is suggested that the Ca2+-activated neutral protease may be involved in muscle fibre necrosis in muscular dystrophy.

Animals↗