Biomedical subjects

H G Dunn

Publications and source records attributed to H G Dunn.

At least 55 records · Page 3Linked to original sources

PubMed1976

Infantile polymyoclonus: Its occurrence in second cousins.

Two second cousins with infantile polymyoclonus are described. All other published cases in the literature are sporadic,and the occurrence of two cases of this exceedingly rare disorder in one family raises the possibility of genetic transmission. Careful examination of the family pedigree is indicated in this disorder.

Child↗

PubMed1976

Krabbe's leukodystrophy without globoid cells.

Krabbe's infantile cerebral sclerosis with a prolonged course was present in a boy who became increasingly hypertonic during infancy and had an increased protein level in the spinal fluid. At 4 years he showed significant growth failure, profound mental retardation, spastic quadriplegia, bilateral optic atrophy, and depressed tendon reflexes. Conduction velocity in motor fibers of the median nerve had become progressively impaired. Autopsy at 5 years 10 months showed severe leukodystrophy with demyelination and gliosis. No stored breakdown products or globoid cells were seen in the brain. Galactosyl ceramide beta-galactosidase was virtually absent, and hardly any myelin was demonstrable on chemical and electron microscopic studies. The presence of globoid cells may not be essential for the pathologic diagnosis of Krabbe's leukodystrophy in the presence of appropriate enzyme deficiency.

Brain↗

PubMed1976

Lactic acidosis in childhood.

Children with chronic metabolic acidosis should be investigated to determine the presence of an organic acid, especially when the plasma electrolyte profile shows a deficiency of anion. One of the organic acids that should be looked for in such a patient is lactic acid. Lactic acidosis due to tissue hypoxia is a well-known phenomenon (e.g., in shock and cardiopulmonary disease) and has not been discussed in this essay; nor has lactic acidosis due to exogenous causes like infusion of fructose or sorbitol, or admiministration of phenformin. Chronic lactic acidosis in infancy is a rare condition. It may be associated with glycogen storage disease Type 1, fructose diphosphatase deficiency, methylmalonic acidemia, propionic acidemia, pyruvate carboxylase or dehydrogenase deficiency and Leigh's subacute necrotizing encephalomyelopathy (SNE). Some patients with chronic lactic acidosis do not have nay of these diseases and comprise an "idiopathic" group. This is a heterogeneous group, probably having several different causes for the metabolic error. In Leigh's SNE, a metabolic block in the formation of thiamine triphosphate in brain has been demonstrated and has been attributed to the presence of an inhibitor of thiamine pyrophosphate-adenosine triphosphate (TPP-ATP) phosphoryl transferase in body fluids. The inhibitor has also been encountered in cases of intermittent cerebellar ataxia and of primary hypoventilation (Ondine's curse), which may represent variants of Leigh's disease. Increased blood levels of lactate, pyruvate and alanine frequently are encountered in SNE, but it still is not clear whether they are due to a primary or secondary disturbance in the catabolism of pyruvate. Disturbed lactate and pyruvate metabolism has also been encountered in isolated cases of mental retardation and growth failure, in mitochondrial myopathies and in polyneuropathies, and may be expected to occur in Wernicke's encephalopathy. Finally, it has been noted in malignancy and in association with other rare metabolic disorders.

Acidosis↗

PubMed1974

Sex-linked hereditary ataxic deplegia, the borderland between cerebral palsy and Pelizaeus-Merzbacher disease.

After a review of the literature concerning hereditary cases of cerebral palsy, a family is reported in which ataxic diplegia appears to be inherited as a sex-linked and probably recessive condition occurring in 3 males in successive generations. This ataxic diplegia, occurring after an unremarkable perinatal course, is associated with mild to moderate mental retardation, congenitial nystagmus and significantly small stature and prevents the acquisition of free walking. Associated extrapyramidal features may gradually become more marked, while the nystagmus may subside. The condition is similar to that described in three previous reports in the literature. No evidence of linkage with other sex-linked disorders has been found, Xga typing showed that recombination between the Xg locus and the locus for hereditary ataxic deplegia has occurred once out of three possible opportunities. In the absence of neuropathological findings or specific biochemical tests, the differential diagnosis from Pelizaeus-Merzbacher disease cannot be made with certainty. The differentiation from other progressive sex-linked neurological disorders is discussed.

Ataxia↗

PubMed1973

Carotenemia in mentally retarded children. I. Incidence and etiology.

The incidence and etiology of carotenemia in mentally retarded children were examined. Fasting serum carotenoid and vitamin A levels were measured in 77 profoundly mentally retarded children aged 3 to 19 years who were receiving a standard diet containing 2000 IU of carotene (expressed in terms of vitamin A activity) and supplemented by 2000 IU of vitamin A daily. Seventeen of the 77 patients had serum carotenoid levels of more than 300 mug./ml. The particulate size of food had a significant inverse relationship to serum carotenoid levels and was an important factor in determining carotenemia. The serum vitamin A level was also higher in children on homogenized diet than in those on pureed feeds, while the lowest level was noted among patients on a chopped diet. Besides particulate size of food, other factors may also be operative in determining carotenemia.

Body Weight↗

PubMed1973