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Biomedical subjects

S K Wadman

Publications and source records attributed to S K Wadman.

At least 55 records · Page 3Linked to original sources
PubMed1985

Thiamine-responsive inborn errors of metabolism.

Three different inherited disorders are known in which thiamine may exert a beneficial effect: maple syrup urine disease (MSUD), lactic acidaemia and the syndrome of megaloblastic anaemia with sensorineural deafness and diabetes mellitus. The amounts of thiamine which were used for long-term treatment varied from 20 to 2400 mg day-1. Additional treatment, such as the reduction of dietary branched chain amino acids in MSUD, could not be omitted in some cases. It has been shown that the vitamin improves the stability of the branched chain ketoacid decarboxylase, although some weeks may be needed to observe the in vivo effect of treatment. A prolonged trial with high doses of thiamine should always be given.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗
PubMed1985

Medium-chain acyl-CoA dehydrogenase deficiency in two siblings with a Reye-like syndrome.

An increasing number of reports indicate that patients with some inherited metabolic diseases may have symptoms resembling those of Reye syndrome. We describe two siblings who developed a Reye-like syndrome at ages 16 and 18 months, respectively, after a viral illness and salicylate therapy. Both had fasting hypoglycemia and hypoketonemia. At the time of the acute episode and after ingestion of a medium-chain triglyceride load, one of them excreted large amounts of abnormal metabolites derived from the omega- and (omega-1)-oxidation of medium-chain fatty acids. Medium-chain acyl-CoA dehydrogenase activity was lower than 20% of control values in fibroblasts from both patients. This enzyme defect should be considered in children with a Reye-like syndrome with these distinctive manifestations.

Acyl-CoA Dehydrogenase↗
PubMed1985

Octanoic acidemia and octanoylcarnitine excretion with dicarboxylic aciduria due to defective oxidation of medium-chain fatty acids.

Five patients aged 7 to 21 months are described who developed attacks of coma after a short prodromal illness with diarrhea or vomiting or both. Four had concomitant hypoglycemia, and all had hypoketonemia, with excessive urinary excretion of medium-chain dicarboxylic acids, medium-chain (omega-1)-hydroxyacids, suberylglycine, hexanoylglycine, and octanoylcarnitine. All patients accumulated octanoic acid, decanoic acid, and cis-4-decenoic acid in plasma. Fibroblasts from three patients showed a decreased rate of octanoate oxidation (10%, 12%, and 29% of control values, respectively). These findings suggest a deficiency of medium-chain acyl-CoA dehydrogenase, most probably an autosomal recessive inherited metabolic disorder. Two of the patients died during an acute attack, and a third had severe neurologic sequelae; the two remaining patients recovered. Plasma free carnitine levels were low, but total carnitine was normal. The three surviving patients underwent a fasting test, which did not lead to hypoglycemia, although hypoketonemia, dicarboxylic aciduria, and excessive mobilization of fatty acids did occur. The surviving patients were maintained on frequent carbohydrate-enriched meals.

Acyl-CoA Dehydrogenases↗
PubMed1985

Absence of hepatic molybdenum cofactor. An inborn error of metabolism associated with lens dislocation.

There are many causes of lens dislocation in man. Amongst these are two inborn errors of sulfur amino acid metabolism, viz., homocystinuria and sulfite oxidase deficiency. To date nine patients have been found in whom a combined deficiency of sulfite oxidase and xanthine dehydrogenase was observed. This inherited disease is due to a defective synthesis of molybdenum cofactor, an essential component for the assembly of both enzymes. The main clinical symptoms of these patients were: facial dysmorphic features, severe feeding difficulties, mental retardation, abnormal muscle tone, severe seizures and myoclonia. Four out of nine patients had dislocated eye lenses. The main biochemical findings included hypouricemia, xanthinuria, an increased excretion of sulfite, thiosulfate, S-sulfocysteine, taurine and a decreased excretion of inorganic sulfate. The prognosis of the disease is poor; various attempts at treatment were not successful so far. Prenatal diagnosis by assay of sulfite oxidase in cultured amniotic fluid cells and by direct measurement of amniotic fluid S-sulfocysteine is possible.

Coenzymes↗
PubMed1984

Stable isotope dilution analysis of orotic acid and uracil in amniotic fluid.

Rapid, sensitive and accurate stable isotope dilution assays were developed for the measurement of orotic acid and uracil in amniotic fluid. The method utilizes [15N2]orotic acid and [15N2]uracil as internal standards, isolation by liquid partition chromatography and quantitation by chemical ionization selected ion monitoring gas chromatography-mass spectrometry. Orotic acid at a concentration of 0.26 +/- 0.05 mumol/l and uracil at a concentration of 0.55 +/- 0.13 mumol/l were detectable in normal amniotic fluid. As affected fetuses with argininosuccinate synthetase or ornithine carbamoyl transferase deficiency showed no significant elevation of orotic acid and/or uracil in their surrounding amniotic fluids, this method unfortunately seemed not to be useful for prenatal diagnosis of these inherited disorders. Nevertheless, it provides significant advantage over available methods for the quantitation of orotic acid and uracil in which the analysis of these compounds must be very accurate, highly specific and sensitive (e.g. detection of heterozygosity for ornithine carbamoyl transferase deficiency).

Amniotic Fluid↗
PubMed1984

Dihydropyrimidine dehydrogenase deficiency leading to thymine-uraciluria. An inborn error of pyrimidine metabolism.

Three unrelated patients with excessive thymine-uraciluria due to dihydropyrimidine dehydrogenase deficiency are described. Excretory values (mmol/g creatinine) were: uracil 2.0-10.5, thymine 2.3-7.5, 5-hydroxymethyluracil 0.2-0.9. Orally administered (index patient) uracil and thymine were excreted for the greater part whilst dihydrouracil and S-dihydrothymine were mainly metabolised. Dihydropyrimidine dehydrogenase activities (nmol X h-1 X mg-1 protein) in leucocytes were 0.04, 0.01 and less than 0.01 in the patients, 0.31-1.66 in their parents, and 1.01-4.46 in controls (n = 4). The patients presented with a non-specific clinical picture of cerebral dysfunction.

Adolescent↗
PubMed1984

Systemic carnitine deficiency: benefit of oral carnitine supplements vs. persisting biochemical abnormalities.

A patient is described who was admitted with a condition similar to the Reye syndrome at the age of 9 months. Hypoglycemia, hyperammonemia, hepatomegaly, and lethargy were present. The plasma concentrations of free and acylcarnitine were extremely low and the urine contained excessive amounts of dicarboxylic acids. Extensive biochemical and histological investigations of biopsied liver and muscle led to the diagnosis of systemic carnitine deficiency. The patient was put on oral carnitine treatment, upon which he remained clinically well. A prolonged fasting test during this treatment gave abnormal results: there was no ketonemia, but an increase of omega-oxidation of fatty acids. In spite of the treatment the liver and muscle carnitine content remained below normal.

Carnitine↗
PubMed1984

Prenatal diagnosis of glutaric aciduria type II by direct chemical analysis of dicarboxylic acids in amniotic fluid.

A method for the measurement of dicarboxylic acids in amniotic fluid was developed that utilizes isolation of the acids by liquid partition chromatography and quantification by ammonia chemical ionization selected ion monitoring, gas chromatography-mass spectrometry. The concentrations of dicarboxylic acids in ten normal samples of amniotic fluid (mumol/l +/- 1 S.D.) were glutaric acid 0.91 +/- 0.15, adipic acid 0.33 +/- 0.08, suberic acid 0.27 +/- 0.08, and sebacic acid 0.21 +/- 0.10. A highly elevated concentration of 14.48 mumol/l glutaric acid was found in the amniotic fluid of a pregnancy in which the fetus was affected with glutaric aciduria type II. Adipic, suberic and sebacic acids were also significantly elevated. The dicarboxylic acids were normal in the amniotic fluid of a pregnancy at risk for glutaric aciduria type II in which the fetus was unaffected. This method is suitable for the rapid prenatal diagnosis of glutaric aciduria types I and II and of potential value for the prenatal diagnosis of other inherited disorders in which dicarboxylic acids accumulate.

Adipates↗
PubMed1984

Clinical and biochemical studies of high-dose thymidine treatment in patients with solid tumors.

In a clinical study of high-dose thymidine (TdR) treatment, toxic effects, TdR metabolism, and the influence of TdR on pyrimidine and purine metabolism were examined. Ten patients with solid tumors were treated with continuous infusion of TdR at 34-75 g/m2/day for 3 to 5 days. Hematologic toxicity occurred with 5-day TdR infusion at 75 g/m2/day but not when plasma TdR concentration failed to reach millimolar levels. In three patients who received similar TdR doses, plasma TdR levels were related to elimination rates of TdR and its metabolites from plasma. In one patient in whom urinary excretion was studied, 100% of the TdR dose given was recovered in the form of TdR, thymine (Thy), beta-aminoisobutyrate, and 5-hydroxymethyluracil (5-HMUra). The latter metabolite, which had not been previously described in high-dose TdR treatment, was also found in plasma at levels from 5% to 10% of those of TdR. No effects of high-dose TdR infusion on purine levels in plasma were observed, while a substantial increase in uracil levels was noted both in plasma and urine. These data provide further information on high-dose TdR treatment with regard to clinical, pharmacokinetic, and biochemical effects.

Aged↗