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Biomedical subjects

A R Rushton

Publications and source records attributed to A R Rushton.

At least 19 recordsLinked to original sources
PubMed1983

Hepatic fibrosis in fetal alcohol syndrome. Pathologic similarities to adult alcoholic liver disease.

The light- and electron-microscopic changes in a biopsy of the liver obtained at age 17 mo from a child with fetal alcohol syndrome were studied. At the time of biopsy, hepatomegaly and raised serum transaminases were present as well as neurologic and growth defects and the typical facial anomalies seen in this syndrome. Light microscopy of the liver biopsy specimen revealed parenchymal fat with portal and perisinusoidal fibrosis. Ultrastructurally, perisinusoidal spaces contained deposits of intermediate-size and large collagen fibers, myofibroblasts and occasional Ito cells, and subendothelial basement membrane-like material. These changes resemble those seen in adult human and baboon alcoholic liver disease and suggest that hepatic fibrosis in fetal alcohol syndrome has a similar pathogenesis.

Female↗
PubMed1982

The role of the chest radiograph in the management of childhood asthma.

Emergency Room records were analyzed retrospectively for 1548 asthma patient visits over a 24-month period. Chest x-rays were obtained during 391 visits. Five per cent had focal atelectasis, ten per cent had a pulmonary infiltrate. There was no difference between the x-ray results of those children successfully treated as outpatients and those requiring hospitalization. Physicians frequently ordered x-rays for asthmatic children under 5 years of age, for those with temperature greater than 38.3 C, symptoms longer than 2 days, respiratory rate greater than 40, a more severe attack with asthma score greater than 3, or pulmonary rales. Significantly abnormal chest radiographs (focal atelectasis or pulmonary infiltrate) were found only in patients under 5 years old or in older patients with pulmonary rales. The other patient characteristics which appeared to indicate a more severe asthma attack did not correlate with abnormal radiograph reports. The routine chest x-ray does not appear to provide useful information for the design of treatment plans for children with asthma.

Age Factors↗
PubMed1981

Computed tomography in the diagnosis of Canavan's disease.

Computed tomography (CT scan) demonstrated a symmetrical decrease in white matter attenuation of the cerebral hemispheres of two young children with macrocephaly and normal neurological examination. Subsequent developmental delay led to brain biopsy, which documented Canavan's disease (spongy degeneration of the brain, Van Bogaert-Bertrand type). The CT scans obtained from these patients with proved Canavan's disease appeared to be quite characteristic in differentiating this disorder from Alexander's disease and adrenoleukodystrophy (Schilder's disease). The CT scan may decrease the necessity for diagnostic brain biopsy in these white matter disorders.

Biopsy↗
PubMed1981

Hereditary ectodermal dysplasia, olivopontocerebellar degeneration, short stature, and hypogonadism.

Two teenaged children born of normal parents in a consanguineous family had evidence of abnormal neurological, endocrine, and ectodermal development. They had mental retardation, hearing loss, ocular dysmetria, hyperreflexia, and ataxia consistent with olivopontocerebellar degeneration. They had hypogonadotrophic hypogonadism and extremely short stature despite normal serum growth hormone and somatomedin-C. There was also hypodontia with peg shaped teeth and mid-face hypoplasia. This syndrome of hypoplasia of mid-lind structures appeared to be inherited as an autosomal recessive trait.

Adolescent↗
PubMed1980

The genetics of fibromuscular dysplasia.

Fibromuscular dysplasia (FMD) is an arterial occlusive disorder of young people that reportedly has affected more than one sibling in several families. A formal pedigree analysis was conducted in 20 families in which at least one member had documented FMD. Clinical symptoms compatible with the disorder were sought in all available family members. In eight families (40%), only the index patient seemed to be affected. The other 12 families contained between one and 11 other relatives who appeared to have FMD. Vertical transmission of the disease was demonstrated repeatedly. There was no consanguinity, and both sexes were equally afflicted. The inheritance pattern for FMD in this investigation was most consistent with an autosomal dominant trait with variable penetrance.

Adolescent↗
PubMed1979

Sex-linked inheritance of cleft palate.

A family pedigree is reported in which males in four generations are affected with midline isolated cleft palate. This is the second report of cleft palate inherited as a sex-linked recessive trait, and it emphasizes the importance of careful pedigree construction when counseling families of children afflicted with this disorder.

Adult↗
PubMed1978

Liquid nitrogen storage and human chromosome composition of human-mouse hybrid cells.

The human chromosome complement of eight human-mouse hybrid cell strains was studied with fluorescent banding before and after rejuvenation of these cells from liquid nitrogen storage. The karyotype remained essentially stable in several cell strains, while in others both human and mouse chromosomes were lost. A third group demonstrated loss of only human chromosomes. The loss of particular human chromosomes after the rejuvenation process was shown to be statistically significant in four of the eight hybrid cell strains. These preliminary results suggest that karyotypic constancy cannot be assumed in human-mouse hybrid cells subjected to rejuvenation from liquid nitrogen storage.

Animals↗
PubMed1977

The effect of glycosaminoglycans on the in vitro activity of human skin fibroblast glycosphingolipid beta-galactosidases and neuraminidases.

The apparent low level of synthetic substrate beta-D-galactosidase activity in liver from patients with the Hurler-Hunter syndrome is caused by the inhibitory effect of accumulated glycosaminoglycans. We have demonstrated complete inhibition of GM1 ganglioside beta-galactosidase activity in vitro by both heparan sulfate and dermatan sulfate, but the effect on lactosylceramide and galactosylceramide hydrolysis was less marked. In contrast, lysosomal neuraminidase activity in vitro was enhanced by the addition of glycosaminoglycans. These observations are discussed in relationship to the observed storage pattern of glycosphingolipids in liver from patients with mucopolysaccharidoses.

Cells, Cultured↗
PubMed1977

Genetic linkage studies of the human glycosphingolipid beta-galactosidases.

The genetic linkage relationships of the human glycosphingolipid beta-galactosidases were determined using human--mouse somatic cell hybrids. A new method was devised for the estimation of human galactosylceramide, lactosylceramide, and GMI-ganglioside beta-galactosidase activities in the presence of their mouse counterparts, which takes advantage of the reproducible specific activity of lysosomal hydrolases under a given set of culture conditions and is based on differences in both pH optima and sensitivity to chloride ion. Human and mouse chromosomes were identified by their characteristic banding patterns obtained after quinacrine staining, and the optimum glycolipid beta-galactosidase activity was determined for three different substrates. A ratio was defined for each activity which was the specific activity at the human pH optimum divided by the specific activity at the mouse pH optimum. Linear regression analysis was used to test for concordant segregation between pH ratios for each enzyme and the frequency of occurrence of different human chromosomes in the man--mouse somatic hybrid clones. The results obtained from two independent series of hybrid clones indicated that human beta-galactosidase activities consistently segregated with human chromosome 12 in these somatic cell hybrids.

Animals↗
PubMed1976

Quantitative analysis of human chromosome segregation in man-mouse somatic cell hybrids.

The presumed random and independent process of human chromosome segregation in man-mouse somatic cell hybrids was studied. The results of chromosome analysis on 196 cells from 15 related hybrid strains have provided the first convincing evidence that segregation of human chromosomes can be nonindependent and often concordant. Different human chromosomes were not retained with equal frequency in these hybrid clones. Some were present in 80% of all the cells, whereas others appeared in less than 10% of the same cells. Linear regression analysis was used to test for correlation of the frequencies of all pair-wise combinations of human chromosomes present in these hybrid clones. Twenty-two of 136 possible correlations were statistically significant, indicating that concordant segregation of particular pairs of human chromosomes is a rather frequent occurrence.

Animals↗
PubMed1975

A genetic model for the evolution of the glycosphingolipids.

The glycosphingolipids have been found in many animal tissues, but the complexity of their molecular structure varies considerably among the different phyla. Relatively simple structures have been found in invertebrate species, while the most complex have been demonstrated in brain tissue of modern fishes and amphibians. The data on the phylogenetic distribution of the glycosphingolipids has been interpreted to indicate that a significant number of gene duplications, involving many different structural genes, may have occurred during a few specific periods of vertebrate evolution. The transition from invertebrate to jawless vertebrate, the divergence of rays and skates from true sharks, the advent of modern bony fishes and the transition from aquatic to terrestrial vertebrates, each could have veen accompained by duplications of genes involved in the synthesis and degradation of glycosphingolipids. The evolutionary study of such a multi-enzyme system may be one means to detect alterations in the genome as a whole. The apparent correspondence in time of these gene duplications involved in glycosphingolipid metabolism and periods of rapid vertebrate evolution which may have been accompanied by significant increases in the amount of cellular DNA suggests that such changes may have occurred via the mechanism of tetraploidization.

Biological Evolution↗
PubMed1975

Glycosphinoglipid beta-galactosidases of cultured mammalian cells. Characterization of the enzymes from mouse cell line lmtk and human Lesch-Nyhan fibroblasts.

Evidence is presented for the existence of three distinct mammalian glycosphingolipid beta-galactosidase responsible for the hydrolysis of galactosylceramide, lactosylceramide and GM1 gangliside, respectively. Activity toward the (L-3-H)galactose-labeled substrates differed with respect to pH optimum, thermostability, effect of NaCl and inhibition by glycosides and related glycosphinglpids. Comparison of these enzymic acitivites in cultured mouse cell line LMTK- and human beta-galactosiddases could probably be detected in future experiments with somatic cell hybrids (formed by the fusion of these two cell strains by specifically inhibiting activity of mouse origin.

Animals↗