Branched-chain alpha-keto acid dehydrogenase (BCKDH) complexes of lymphoblastoid cell lines derived from patients with classical maple syrup urine disease (MSUD) phenotypes were studied in terms of their catalytic functions and analyzed by immunoblotting, using affinity purified anti-bovine BCKDH antibody. Kinetic studies on three cell lines derived from patients with the classical phenotype showed sigmoidal or near sigmoidal kinetics for overall BCKDH activity and a deficiency of the E1 component activity. An immunoblot study revealed a markedly decreased amount of the E1 beta subunit accompanied by weak staining of the E1 alpha subunit. The E2 and E3 component exhibited a cross-reactive peptide. Thus, in at least some patients with MSUD, mutations of the E1 beta subunit might provide an explanation for the altered kinetic properties of the BCKDH complex.

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

PubMed1985

The infantile form of sialidosis type II associated with congenital adrenal hyperplasia: possible linkage between HLA and the neuraminidase deficiency gene.

The possible genetic linkage between HLA and neuraminidase deficiency was studied in a female patient with combined abnormalities of the infantile form of sialidosis type II and congenital adrenal hyperplasia caused by 21-hydroxylase deficiency, and six members of her family. Her parents were consanguineous. The patient has the homozygous HLA haplotypes, TS-1, Cw3, DRw9. Four of the tested family members, including a distant male relative with congenital adrenal hyperplasia, were heterozygous of this HLA complex, and the neuraminidase activities in their skin fibroblasts and/or lymphocytes showed values between those of the patient and controls (25-48%), suggesting a carrier state of sialidosis. This indicates that the neuraminidase deficiency gene, similar to the 21-hydroxylase deficiency gene, is closely linked to the HLA genotype and is located on chromosome 6.

Adrenal Hyperplasia, Congenital↗

PubMed1985

[Analysis of ALL lymphoblasts proteins by two-dimensional gel electrophoresis].

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Child↗

PubMed1984

Study on established lymphoid cells in maple syrup urine disease. Correlation with clinical heterogeneity.

Branched-chain keto acid dehydrogenase complex (BCKAD) was measured in lymphoid cells established from five patients with maple syrup urine disease (MSUD) and six control subjects. Two other MSUD lymphoid cell lines obtained from The Human Genetic Mutant Cell Repository were used as references. One day after subculture, the cells grew logarithmically up to 4-5 days. With this cell growth, BCKAD activity increased greatly in controls, but not in MSUD cells. The maximum BCKAD activity of MSUD cells was less than 7% and 13%-16% of the control in classic and variant types, respectively. Leucine added to culture medium at the concentration of 10-20 mM significantly inhibited cell growth in MSUD cells alone, and with increasing concentration and impaired enzyme activity in a cell line, the effect became more prominent. The effects of isoleucine and valine were mild and did not differ between control and MSUD cells.

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

PubMed1984

Complementation analysis in lymphoid cells from five patients with different forms of maple syrup urine disease.

The possibility of genetic heterogeneity in maple syrup urine disease was investigated by measuring branched-chain ketoacid dehydrogenase in polyethylene glycol-induced heterokaryons of lymphoid cells. The lymphoid cell lines from five patients with varying forms of the disease were established after incubation with Epstein-Barr virus. The results suggested that there are at least two genetic complementation groups in the disease.

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

PubMed1984

Citrullinemia presenting as uncontrollable epilepsy.

We report the case of a 16-year-old girl with a variant form of citrullinemia who had been treated with anticonvulsants for uncontrolled epilepsy during the last 4 years. The diagnosis of citrullinemia was made because she had elevated values for serum citrulline (about 10 times control levels), elevated blood ammonia (over 400 micrograms/dl) and reduced activity of argininosuccinate synthetase in the biopsied liver tissue. Her EEG showed high voltage slow activity, but not triphasic waves, when she had high concentrations of blood ammonia. Treatment with a low-protein diet and sodium benzoate resulted in a normalized blood ammonia level, but her plasma citrulline levels remained unchanged. After the therapy she had neither convulsions nor seizure discharges on EEG, even when all anticonvulsant drug therapy was stopped. Thus it is suggested that hyperammonemia may account for the observed abnormal EEG findings, and triphasic waves on EEG are not always recorded in cases of hyperammonemia.

Adolescent↗

PubMed1983

Unique pattern of Epstein-Barr virus specific antibodies in recurrent parotitis.

Sera from 34 children with recurrent parotitis were measured by indirect immunofluorescence technique for antibody levels to several Epstein-Barr virus (EBV) antigens. IgG antibodies to EBV-capsid antigen (VCA) and EBV-associated nuclear antigen, often at high titres, were found in 29 of these patients, of whom 20 also had IgA antibody to VCA. Antibody level to early antigen complex (R and D) rose in 19 patients, of whom 18 had antibody to the R component alone. The abnormal patterns of EBV antibodies persisted for 3-14 months during and after the illness in 8 patients. These observations suggest that EBV infection may be important in the pathogenesis of recurrent parotitis.

Animals↗

PubMed1983

Kinetic analysis of argininosuccinate synthetase in a variant form of citrullinaemia.

Argininosuccinate (ASA) synthetase in the liver from a patient with a variant form of citrullinaemia was analysed. Serum citrulline level was approximately 40 times higher than the control level, and the ASA synthetase activity was approximately 10% that of the control. Other urea cycle enzymes were within normal ranges. The specific activity (enzyme activity/enzyme protein, measured by immunochemical method), pH optimum, Michaelis constants, and thermal denaturation in the presence or absence of ASA were similar to those in enzymes obtained from the normal and the patient's liver cells. No in vitro effect of the patient's liver homogenate on ASA synthetase in normal liver was observed. Serum citrulline levels of the patient's parents and young brother were at the maximal level of control at fasting and definitely elevated 4 h after citrulline loading (100 mg/kg).

Adult↗

PubMed1982

Ornithine transcarbamylase (OTC) in white blood cells and jejunal mucosa.

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Cells, Cultured↗

PubMed1980

Ornithine transcarbamylase (OTC) in white blood cells.

A radiochemical assay method of ornithine transcarbamylase (OTC) was developed using labeled carbamyl phosphate as a substrate. The enzyme activities determined by this method in peripheral white blood cells from ten normal subjects were 1.32 +/- 0.95 nmoles/mg/hr and the apparent Km's, when assayed at pH 8.5, were 6.4 mM for ornithine and 0.6 mM for carbamyl phosphate. On the contrary, the apparent Km's of human liver OTC were 0.6 mM for ornithine and 0.12 mM for carbamyl phosphate. The average OTC activity of granulocytes was 1.0 nmoles/mg/hr, whereas that of mononuclear cells was 0.4 mmoles/mg/hr. Lymphoid cell lines were established from three normal subjects and an OTC-deficient infant. All these cell lines demonstrated no OTC activity. When arginine was removed from the medium and replaced by ornithine, the lymphoid cells were unable to grow in culture. On autoradiography, the lymphoid cells showed labelling at incubation in the presence of 14C-citrulline, but not with 14C-ornithine.

Amino Acid Metabolism, Inborn Errors↗

PubMed1979

Lysine intolerance in a variant form of citrullinemia.

An oral loading of lysine (100 mg of lysine-HCL/kg was performed in two patients, 18-and 23-yr-old, with a variant form of citrullinemia. Serum citrulline levels were approximately 10 times higher than control level and lysine levels were within the normal range, in contrast to the classical form of the disease in which serum citrulline is approximately 100 times normal levels and hyperlysinemia is usually present. After lysine loading, lysine levels rose sharply and clearance was decreased. Blood ammonia rose approximately 2.5 times. Lysine, citrulline, and arginine were markedly elevated in urine, collected 90--210 min after the lysine loading. Baseline homocitrulline and homoarginine excretion was elevated and increased further after the load.

Adolescent↗

PubMed1978

Methylmalonic acidemia.

A patient presenting with severe metabolic acidosis accompanied by hyperglycinemia, hyperuricemia, hypoglycemia and hypertammonemia is described. Metabolic acidosis was found to be due to accumulated methylmalonic acid and did not respond to vitamin B12 administration. The patient showed favorable growth and development when kept on a low isoleucine, methionine, threonine and valine diet. In vitro studies using a lymphoid cell line derived from the patient showed a deficiency of methylmalonyl-CoA carbonyl-mutase.

Acidosis↗

PubMed1977

Lysosomal enzyme activities in cultured lymphoid cell lines.

Several lysosomal enzyme activities in cultured lymphoid cell lines were studied during 3 phases of cell culture; logarithmic growth phase, stationary phase and decline phase. Enzyme induction during cell growth was found in N-acetyl-hexosaminidase, beta-galactosidase and alpha-L-fucosidase, but no induction in alpha-D-mannosidase, alpha-glucosidase and beta-glucuronidase. The latter two enzymes were unchanged during all cell culture phases. A drop in alpha-L-fucosidase and alpha-D-mannosidase activity was found during the stationary and decline phases of cell culture.

Cell Division↗