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Biomedical subjects

R Matalon

Publications and source records attributed to R Matalon.

At least 109 records · Page 6Linked to original sources
PubMed1984

Lipoamide dehydrogenase deficiency with primary lactic acidosis: favorable response to treatment with oral lipoic acid.

An 8-month-old boy with severe lactic acidosis was found to have lipoamide dehydrogenase deficiency. Treatment with thiamine, biotin, bicarbonate, protein restriction, and ketogenic diet failed to alleviate the lactic acidosis. Oral administration of lipoic acid 25 to 50 mg/kg produced dramatic improvement in lactic and pyruvic acidemia, which has continued for 2 years and which has been accompanied by clinical improvement.

Acidosis↗
PubMed1984

Biopterin synthesis defects: problems in diagnosis.

Hyperphenylalaninemia due to a biopterin synthesis defect was detected in an infant with decreased biopterin and increased neopterin levels in plasma and urine. Tetrahydrobiopterin (BH4) administration normalized plasma phenylalanine levels. CSF biopterin and neurotransmitter metabolite levels were normal and with the infant's normal growth and development suggest that the defect in biopterin synthesis did not affect CNS biopterin metabolism. Comparison of plasma and urine pterin levels from this patient with levels reported in patients who have neurologic complications fails to reveal differences that would distinguish patients at risk for neurologic problems. CSF pterin and neurotransmitter levels may correlate with neurologic function in these patients. CSF pterin and neurotransmitter determinations should be performed prior to initiation of neurotransmitter precursor and BH4 replacement therapies in patients who were determined to have biopterin synthesis defect(s).

Biopterins↗
PubMed1983

Glucose-6-phosphatase as a marker for tumors of liver and kidney origin.

Glucose-6-phosphatase is primarily a liver and kidney enzyme. This enzyme was studied in various tumors, however, glucose-6-phosphatase activity was found only in tumors of liver, kidney, or adrenal origin. Glucose-6-phosphatase activity was useful in identifying the tissue origin of extrarenal Wilms'. Metastatic tumors within the liver or kidney that originated from other tissues did not have glucose-6-phosphatase activity. Therefore, it is suggested that glucose-6-phosphatase can be used as a specific enzyme marker for tumors of liver and kidney origin.

Carcinoma, Hepatocellular↗
PubMed1983

Delayed dental age in hepatorenal glycogen storage disease.

The dental findings in three patients with hepatorenal glycogen storage disease are described. In two cases, dental maturation and tooth eruption were considerably delayed. In the third case, dental maturation and tooth eruption are normal, possibly because of newer treatment methods of this disease.

Adolescent↗
PubMed1983

Nonketotic hyperglycinemia: treatment with diazepam--a competitor for glycine receptors.

Two female infants with nonketotic hyperglycinemia (NKH) were treated with diazepam for the control of seizures. The first infant had seizures, lethargy, and respiratory distress in the first 24 hours of life. The diagnosis of NKH was made at 3 weeks of age and she was then placed on a regimen of strychnine and a low-protein diet. Strychnine therapy was discontinued after three months of treatment because there was no improvement in the seizure control or in the patient's condition. At 5 months of age the patient was referred to our clinic for further work-up. The second infant had seizures, hypotonia, and respiratory distress shortly after birth. She was treated with phenobarbital and diphenylhydantoin, which had no effect on her seizures. The baby was referred to our clinic at 8 months of age and diagnostic studies revealed NKH. All previous medications were stopped and both infants were placed on diazepam, a competitor for glycine receptors in the CNS. Choline and folic acid were added for one-carbon unit transfer and sodium benzoate to bind excessive glycine. Both infants responded to this treatment with cessation of seizures; they became more responsive and alert, and their EEGs showed remarkable improvement despite the persistence of elevated glycine levels in plasma, CSF, and urine. Diazepam as a competitor for the receptors of glycine may prove helpful in controlling the intractable seizures associated with NKH.

Binding, Competitive↗
PubMed1983

Hunter' syndrome. Ultrastructural features in young children.

Ultrastructural abnormalities in two stepbrothers with Hunter's syndrome, ages 1 and 4 years, were found in cortical neurons, neurons of the myenteric plexus, and skin. Inclusions containing little or no electron-dense material were noted in most tissues, and lamellar figures were restricted to cortical neurons and neurons of the myenteric plexus. These changes correlate with those described in tissues obtained at post mortem.

Cerebral Cortex↗
PubMed1982

Treatment of inborn errors of urea synthesis: activation of alternative pathways of waste nitrogen synthesis and excretion.

Children with inborn errors of urea synthesis accumulate ammonium and other nitrogenous precursors of urea, leading to episodic coma and a high mortality rate. We used alternative pathways for the excretion of waste nitrogen as substitutes for the defective ureagenic pathways in 26 infants. These pathways involve synthesis and excretion of hippurate after sodium benzoate administration, and of citrulline and argininosuccinate after arginine supplementation. The children were treated for seven to 62 months; 22 survived. The mean plasma level of ammonium ( +/- S.E.) was 36 +/- 2 mumol per liter, and that of benzoate was 1.5 +/- 1.0 mg per deciliter. Alternative pathways accounted for between 28 and 59 per cent of the total "effective" excretion of waste nitrogen. Nineteen infants had normal height, weight, and head circumference, and 13 had normal intellectual development. Activation of alternative pathways of waste nitrogen excretion can prolong survival and improve clinical outcome in children with inborn errors of urea synthesis.

Amino Acid Metabolism, Inborn Errors↗
PubMed1982

The use of deuterated phenylalanine for the in vivo assay of phenylalanine hydroxylase activity in children.

Fifteen children, five with phenylketonuria (PKU), five with hyperphenylalaninaemia, and five phenotypically normal but at risk of being carriers for PKU, were given [ring 2H5]phenylalanine orally in amounts ranging from 75 mg/kg to 10 mg/kg. Plasma was assayed for [2H5]phenylalanine and [2H4]tyrosine at hourly intervals, the amino acids being measured as the N-acetyl, n-propyl esters by gas chromatography-mass spectroscopy. The results obtained were calculated as the log of the ratio [2H5]phenylalanine: [2H4]tyrosine in the plasma. The five patients with PKU had ratios of infinity because no [2H4]tyrosine was measured in their plasma during the experimental period. The patients with hyperphenylalaninaemia had log ratios over 2.00 throughout the assay period. Among the five normal children three are considered to be carriers for PKU as the logarithms of the [2H5]phenylalanine: [2H4]tyrosine ratios were 1.77, 1.73, and 1.33 and remained over 1.00 during the assay period. The other children had log ratios of 1.16 and 1.00 at the first hour which dropped below 1.00 subsequently, suggesting normal activity of phenylalanine hydroxylase.

Child↗
PubMed1976

Prenatal diagnosis of inborn errors of metabolism.

More than 50 inborn errors of metabolism can be diagnosed in the fetus. This is accomplished by evaluation of constituents of the cell free amniotic fluid or of cultured or uncultured amniotic fluid cells. Only those syndromes with specific abnormal contributions to amniotic fluid can be so diagnosed. Currently diagnosable diseases and their assay methods are reviewed. Such assay methods must be able to differentiate the unaffected heterozygote from the affected homozygote.

Adult↗