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Biomedical subjects

D T Whelan

Publications and source records attributed to D T Whelan.

At least 19 recordsLinked to original sources
PubMed1987

Experimental hyperphenylalaninemia in the pregnant guinea pig: possible phenylalanine teratogenesis and p-chlorophenylalanine embryotoxicity.

Maternal hyperphenylalaninemia (HPH) due to deficient phenylalanine (Phe) hydroxylation is a recognized human teratogen associated with an increased incidence of intrauterine growth retardation, microcephaly, congenital heart disease, and mental retardation. There are no previous reports of experimental HPH during organogenesis. Sustained HPH was produced in pregnant guinea pigs by adding 3.5% Phe and 1.0% parachlorophenylalanine (pCPA), an inhibitor of Phe hydroxylase, to standard guinea pig chow. Animals consumed the supplemented test diets from gestation day 1 until killed on gestation day 17. Examination of day 17 embryos revealed that embryonic mortality was associated only with maternal pCPA administration and was independent of the degree of maternal HPH. Embryonic malformation was associated with maternal HPH as well as maternal pCPA administration. Both maternal HPH and pCPA administration were associated with embryonic growth retardation. There was no association between maternal food intake or plasma tyrosine levels and embryonic abnormality or mortality. Both Phe and tyrosine were found to be concentrated in gestation day 17 yolk sac fluid when compared to maternal plasma Phe and tyrosine. The association of embryonic malformation and maternal HPH is consistent with human data. The embryotoxicity of pCPA requires further study and highlights the necessity of appropriate controls in models of experimental HPH.

Animals↗
PubMed1983

Fumaric aciduria: a new organic aciduria, associated with mental retardation and speech impairment.

Two siblings are described who present with fumaric aciduria, a hitherto unreported organic aciduria. The results of our analytical investigations using gas chromatography/mass spectrometry, and the clinical presentation of the patients, are consistent with the notion that the fumaric aciduria is caused by an inherited defect which leads to a net secretion of fumaric acid by the renal tubules.

Adult↗
PubMed1983

Mucolipidosis II. The clinical, radiological and biochemical features in three cases.

We report on the clinical, radiological and biochemical features of mucolipidosis II in three infants. One with subtle phenotypical findings died at 2 weeks of age without a specific diagnosis. A sibling who died at 2 years of age and another infant, presently 3.5 years of age manifest all the characteristic features of mucolipidosis II: extreme psychomotor delay and failure to thrive, coarse facial features, gingival hyperplasia, joint stiffness, inguinal hernia and skin induration. The corneae were normal and there was no mucopolysacchariduria. Radiologically, these infants show changes which are characteristic but not specific for mucolipidosis II. Cytologically, skin fibroblasts from these patients demonstrate the lysosomal inclusions typical of I-Cell Disease. Biochemically, cultured skin fibroblasts show deficient activity of arylsulphatase A and B and hexosaminidase A and B. These acid hydrolases were increased markedly in plasma and in the culture medium of the skin fibroblasts.

Cells, Cultured↗
PubMed1983

45,X/46,XX mosaicism in discordant monozygotic twins.

Monozygotic twins discordant for Turner's syndrome were both mosaic for 45,X/46,XX in the blood with the same low frequency of 2% to 3% 45,X cells. However, the fibroblasts of the abnormal girl were all uniformly 45,X whereas her normal twin had only 46,XX cells. Monozygosity was confirmed by genetic markers, chromosome variants, and a single monochorionic placenta with a shared vascular circulation. The mechanism by which this disparate pair developed from a single zygote is suggested.

Dermatoglyphics↗
PubMed1980

A rare case of mosaic Down syndrome 46,XY/46,XY, -21, +i(21q).

Detailed studies were carried out on a patient with a rare type of mosaicism which gave rise to an effective 21 trisomy. The clinical signs of Down syndrome were minimal. The cytogenetic interpretation is that the abnormal clone had an isochromosome derived from a maternal No. 21. The normal cell line appears to be replacing the abnormal clone.

Chromosomes, Human, 21-22 and Y↗
PubMed1979

Methylmalonic acidemia: 6 years' clinical experience with two variants unresponsive to vitamin B12 therapy.

Two infants with lethargy, vomiting, convulsions, coma and marked metabolic acidosis were found to have very high concentrations of methylmalonic acid in their serum and urine. In vitro studies of fibroblasts demonstrated that the infants had different variants of methylmalonic acidemia.Vitamin B(12) was given in two different forms at 1 month of age and at 12 months of age. Each trial continued for 4 months but neither infant showed a clinical or biochemical response.In both infants hyperglycinemia, neutropenia and thrombocytopenia developed during acute metabolic crises only. Hypoglycemia was found in patient 2. Hyperammonemia was severe in patient 2 during acute crises but never appeared in patient 1. When clinically well, both infants continued to excrete abnormal amounts of methylmalonic acid in the urine and both had persistent compensated metabolic acidosis.Marked hyperuricemia developed in patient 1 at 18 months of age and led to progressive renal failure. Allopurinol therapy was necessary to keep the uric acid concentration within the normal range. Renal function returned to normal, as indicated by a marked increase in the renal clearance of creatinine and uric acid.Patient 1 is physically and mentally retarded, and has moderate hypotonia, hepatomegaly and persistent vomiting. Patient 2 has developed normally.The urine concentrations of methylmalonic acid in the four parents were normal.

Amino Acid Metabolism, Inborn Errors↗
PubMed1979

L-Glutaric acidemia: investigation of a patient and his family.

A 5-month-old infant had an unusual combination of clinical signs and symptoms. These consisted of irritability, dystonia, lack of head control, grimacing, opisthotonos, choreoathetoid movements, delayed development, and severe metabolic acidosis. Metabolic investigation by gas-liquid chromatography/mass spectrometry detected urinary organic acids. This confirmed the diagnosis of L-glutaric aciduria. The concentration of L-glutaric acid in the patient's plasma was 2.5 mg/dl (normal range, 0 to 0.1 mg/dl), and in the patient's urine was 4.6 mg/mg of creatinine (normal range, 0 to 0.05 mg/mg of creatinine), but the concentration was not elevated in the plasma and urine of the infant's parents nor of two other family members. No glutaryl-CoA dehydrogenase activity was found in leukocytes taken from the patient. Three of the four family members, including the parents, demonstrated 38%, 42%, and 42% activity, respectively, compared with the activity of normal controls. These findings are consistent with an autosomal recessive disorder involving the metabolism of glutaryl-CoA to crotonyl-Co-a. Dietary restriction was instituted on two separate occasions. First, a low protein diet of 1.6 gm/kg of body weight per day was given, then a low lysine intake of 50 mg/kg/day. These dietary manipulations caused a decrease in the plasma and urine concentrations of L-glutaric acid and beta-hydroxyglutaric acid. However, no effect on the clinical manifestations of the disease was noted.

Amino Acid Metabolism, Inborn Errors↗
PubMed1978

A new variant of methylmalonic acidemia-defective coenzyme-apoenzyme binding in cultured fibroblasts.

Cultured fibroblasts from a patient with methylmalonic acidemia, clinically responsive to vitamin B-12, were studied in vitro. Kinetic analysis revealed abnormal binding of the coenzyme, 5'-deoxyadenosylcobalamin, for its methylmalonyl-CoA carbonylmutase apoenzyme, i.e., KM of 3.8 X 10(-5) M versus control KM of 1.5 X 10(-8) M. These data are interpreted as indicating a structural defect of the apoenzyme at the coenzyme binding site, and represent another variant of this genetic disorder.

Amino Acid Metabolism, Inborn Errors↗
PubMed1976

Citrullinemia: phenotypic variations.

An 18-month-old female infant was found to have citrullinemia on routine plasma screening by the Scriver Method at 5 days of age. At 10 days of age, plasma citrulline concentration was 0.704mumol/ml (normal, 0.010 to 0.030mumol/ml) and has remained 60 to 80 times higher than normal. Urine citrulline concentration was markedly elevated. Hyperammonemia occurred at 1 month of age. The serum ammonia concentration was 473mug/100 ml (normal, 50 to 250 mug/100 ml) and rose to 770mug/100 ml at 4 months of age. Dietary protein was restricted to 1.6 gm/kg/day. Without further change in protein intake, the serum ammonia concentration decreased to 280mug/100 ml and, since then, it has returned to normal. The addition of three synthetic L-amino acids was required for a short time during dietary therapy. At 10 months of age, the infant was given a normal diet. At 18 months of age, her physical and mental development is normal. Activity of argininosuccinic acid synthetase measured in skin fibroblasts was 0.0037mumol of radioactive carbon dioxide per milligram of protein per hour. To demonstrate heterozygosity, fasting plasma citrulline concentrations were measured in five members of the family. Comparison of findings in this patient with those reported in the literature suggests phenotypical variation of the disease, probably due to genetic heterogeneity.

Amino Acids↗
PubMed1975

The oro-facial-digital syndrome.

Two patients, a mother and her daughter, are presented who manifest the clinical features of the oro-facial-digital syndrome (OFD I). Many of these features are shared with Mohr's syndrome (OFD II). Confusion arises when a patient presents with features common to both syndromes. The features which are always or sometimes associated with these syndromes are tabulated. The Tables also show which abnormalities are common to both syndromes and to our cases. Additional clinical and radiological features which have not been considered part of these syndromes are described. We present these cases to suggest that these syndromes should be "lumped" together as one syndrome. We propose expanding this syndrome to include ear and renal abnormalities. Our cases follow an X-linked dominant inheritance pattern and, therefore, do not help determine the genetic controversy of these two syndromes.

Abnormalities, Multiple↗