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Biomedical subjects

G N Donnell

Publications and source records attributed to G N Donnell.

At least 55 records · Page 3Linked to original sources
PubMed1978

Biochemical studies of a human low-activity galactose-1-phosphate uridyl transferase variant.

A low activity galactose-1-phosphate uridyl transferase (transferase) variant in a newborn infant has been demonstrated by biochemical studies in erythrocytes and cultured skin fibroblasts. The newborn infant was a galactosaemic suspect identified in a neonatal metabolic screening programme. On breast feeding, he did well without clinical symptoms of galactosaemia during the first 15 days of life. However, substantial amounts of erythrocyte galactose-1-phosphate and urinary galactitol corresponding to the levels in untreated galactosaemic patients, along with mild amino aciduria, were found. The transferase activity, as measured by a sensitive micro kinetic radioisotopic method, was about 7--10% of the normal. On starch gel electrophoresis, the enzyme from the haemolysate had similar mobility as the normal in Tris--glycine buffer, pH 8.8 and phosphate buffer, pH 7.0, but had a slower mobility than that of the normal in the histidine buffer, pH 7.8. The mobility difference was much clearer in a semipurified enzyme preparation. The transferase enzyme in the haemolysate appeared to be more heat labile.

Cells, Cultured↗
PubMed1977

Prenatal diagnosis of galactosemia.

Prenatal diagnosis of disorders of galactose metabolism was done in one instance in a family with a known galactokinase deficiency and in six cases in five families at risk for galactosemia. The galactokinase activity in cultured amniotic cells was found to be normal, and the diagnosis was confirmed postnatally. In the six pregnancies at risk for galactosemia, four were considered to be unaffected and two to be affected. Of the latter, one was carried to term, and the erythrocyte transferase activity of the baby was shown to be absent. The other pregnancy was terminated, and examination of fetal tissues by biochemical studies confirmed the diagnosis. This experience substantiates the concept that prenatal diagnosis of disorders of galactose metabolism is feasible.

Amniotic Fluid↗
PubMed1977

Radiographic features of fucosidosis.

Fucosidosis is an uncommonly recognized lysosomal storage disease which presents with psychomotor deterioration and progressing in some cases to death. The roentgenographic findings in five boys from three families are described. Skeletal abnormalities of a dysostosis multiplex nature are present and though not diagnostic should direct the clinician to perform appropriate biochemical and tissue assay studies to establish the diagnosis.

Adolescent↗
PubMed1976

Differential fluorescence of sister chromatids with 4'-6-diamidino-2-phenylindole.

Differential fluorescence of sister chromatids and sister chromatid exchanges (SCE) in chromosomes from human lymphocytes grown two replication cycles in medium containing 5-bromodeoxyuridine can be detected by fluorescence microscopy after staining with 4'-6-diamidino-2-phenylindole (DAPI). The DAPI fluorescence appears to be more stable than that of the dye 33258 Hoechst and may provide a more sensitive method for the detection of SCE.

Chromatids↗
PubMed1976

The 9p- syndrome.

Six patients (4 females and 2 males) with terminal deletion of the short arm of chromosome 9 distal to band p22 are described. The disorder constitutes a clinically identifiable syndrome consisting of mental retardation, sociable personality, trigonocephaly, mongoloid eyes, wide flat nasal bridge, anteverted nostrils, long upper lip, short neck, long digits mostly secondary to long middle phalanges, and predominance of whorls on fingers. The findings suggest that the clinical features are antithetical to the trisomy 9p syndrome. The deleted chromosome segment is relatively small and could be easily overlooked. It is hoped that this delineation of clinical features seen in 9,p- patients may help in focusing attention on the small deletion.

Abnormalities, Multiple↗
PubMed1976

Biochemical and genetic studies of plasma and leukocyte alpha-L-fucosidase.

Deficiency of alpha-L-fucosidase in plasma and leukocytes has been demonstrated in three patients affected with fucosidosis. The measurement of plasma fucosidase activity alone is of little diagnostic value. Several normal individuals were found to have extremely low plasma alpha-L-fucosidase activity, but normal activity in leukocyte preparations. The low plasma enzyme activity exhibited by clinically normal individuals appears to be an inherited characteristic. The plasma enzyme was found to be different from that of leukocytes in terms of electrophoretic mobility.

Adult↗
PubMed1976

Comparison of mental development in individuals with mosaic and trisomy 21 Down's syndrome.

During the past 15 years about 350 children with Down's syndrome have been seen at Children's Hospital of Los Angeles for psychological evaluation along with medical visits and other laboratory tests. Among this group there were 25 mosaic Down's syndrome children identified by chromosome analyses. They were matched for sex and chronological age with 25 trisomy 21 subjects and compared on psychological tests. The mosaic group demonstrated significantly higher intellectual potential, better verbal facility, and less visual perceptual difficulties than the trisomy 21 group. Their behavioral adjustment and personality characterisitcs were similar to those observed in other types of Down's syndrome. Since present psychological assessment techniques do not permit reaching valid conclusions about the ultimate intellectual status in very young infants with Down's syndrome, physicians and other professionals need to be careful when recommending early placement outside the home based merely upon the diagnosis.

Adolescent↗
PubMed1976

The 9p--syndrome.

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Abnormalities, Multiple↗