Chemical diagnosis of amino acid abnormalities. Possibilities and desirabilities.
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Biomedical subjects
Publications and source records attributed to S K Wadman.
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A gas chromatographic method is described for the determination of urinary vanilglycolic acid, vanilglycol, vanilacetic acid and vanillactic acid as their trimethylsilyl derivatives. These metabolites are chemical parameters for the dignosis of neurogenic tumours. Their determination is especially recommended in order to evaluate the effect of the therapy. Results in normals and controls are given. Data in a number of selected patients with neuroblastoma, ganglioneuroma and phaeochromocytoma are presented and discussed.
A patient is described with glyceric acidemia and glyceric aciduria. The main clinical problems in infancy were severe metabolic acidosis and failure to thrive. The patient needs permanent treatment with bicarbonate. Hyperglycinemia, as described in the first case discovered elsewhere, was not present. The glyceric acid was found to have the D-configuration, as analyzed by capillary gas chromatography of its di-O-acetyl-l-menthyl ester. The abnormality may result from a defect in serine metabolism.
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A report is given on a hitherto undescribed metabolic disorder, characterized clinically by fatal neonatal acidosis, hypoglycemia and a strong 'sweaty-feet' odour. Biochemical features were a massive urinary excretion of glutaric and lactic acids. Isobutyric, isovaleric and alpha-methylbutyric acids were also greatly increased, followed by adipic, ethylmalonic, alpha-hydroxybutyric, n-butyric, beta-hydroxybutyric, sebacic, suberic, propionic, alpha-hydroxyisovaleric and hexanoic acids. The serum level of glutaric acid was highly elevated. In the serum there were also abnormal levels of lactic, alpha-hydroxybutyric, adipic, suberic, p-hydroxyphenyllactic, myristic, hexadecenoic, palmitic, oleic and stearic acids. Plasma lysine and valine were also elevated. Degradation of 14C-labelled glutaric acid and 14C-labelled branched-chain amino acids, alpha-ketoisovaleric and alpha-ketoisocaproic acids in intact fibroblasts was decreased, whereas that of pyruvic acid was normal. The defect was tentatively supposed to be localized at the level of the metabolism of a range of acyl-CoA compounds. The name glutaric aciduria 'type II' is proposed for the patient's disease.
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A patient with a Lowe syndrome was observed from birth. Progressive hyperchloraemic renal tubular acidosis, hypophosphataemia, hyperphosphaturia and generalized hyperaminoaciduria had developed in infancy. Supplementary vitamin D, alkali and a high intake of dietary phosphate were unsuccessful in controlling the severe phosphate diabetes and rickets. Contraction of the extracellular fluid volume by dietary sodium restriction resulted in correction of the acidosis, hypophosphataemia, hyperaminoaciduria, and hyperphosphaturia, and healing of the rickets.
A positive ferric chloride reaction was found at routine examination of the urine of a 14 year old mentally normal girl, admitted for complaints of headache and other meningitis-like symptoms. It turned out that she excreted permanently increased amounts of phenylpyruvic, phenyllactic and o-hydroxyphenylacetic acids, but phenylacetic acid (free plus conjugated) was normal. Fasting serum phenylalanine was not increased nor was urinary phenylalanine. On loading with L-phenylalanine (100 mg/kg) a normal serum phenylalanine response followed, but urinary phenylpyruvic, phenyllactic and o-hydroxyphenylacetic acids increased further. Phenylacetic acid responded too, but remained in the normal range. In addition to the above-mentioned abnormalities the urine contained a still unidentified abnormal acid, which also increased after loading with phenylalanine. Her 12 year old healthy sister showed the same chemical abnormality. Two older brothers and the parents had normal excretions. The enzyme defect has not been identified. As a possibility the defective decarboxylation of phenylpyruvic acid is proposed.
Tyrosyluria and for a part also tyrosinemia were studied in 60 healthy prematures of various birth weights and gestational ages. The first analyses were performed between the 6th and the 14th day after birth. A normal milk diet was given and the protein-intake was between 3 and 4 g/kg. After the first collection of urine half the patients received extra ascorbic acid, 100 mg/kg daily. Urinary analyses of tyrosine and p-hydroxyphenyl metabolites were performed once a week, until the excretion of p-hydroxyphenylpyruvic plus p-hydroxyphenyllactic acids was lower than 5 mmoles per gram creatinine. In 22 out of the 60 prematures (or 37%) a tyrosyluria of more than 5 mmoles/g creatinine and in 19 out of 44 (43%) patients analysed serum tyrosine was higher than 5 mg/100 ml at first analysis. No inverse correlation between tyrosyluria and tyrosinemia on the one hand and birth weight and gestational age on the other hand existed. But in children with a delayed intra-uterine development the incidence of tyrosyluria was higher as prematurity was more pronounced. Ascorbic acid had no effect on the rate of disappearance of tyrosyluria. It was concluded that the addition of extra vitamin C to the diet of prematures is not useful for the normalization of tyrosine metabolism.
An unknown urinary amino acid, present in small amounts in many children with various diseases, has been isolated and identified as N-Epsilon-(carboxymethyl)lysine. The identity of this compound was confirmed by synthesis. Its chromatographical characteristics are described. The compound also occurred in the urine of prematurely born infants. Even in healthy adults trace amounts could be detected. In a few patients strikingly higher excretions were observed, up to 67 mg/g creatinine, as determined by cation-exchange column chromatography. No clear correlation with a distinct clinical picture could be established. Speculations are given about the origin of the compound.
Investigation of a psychomotorically retarded girl showed excretion of abnormal amounts of alpha-ketoadipic acid, alpha-hydroxyadipic acid, alpha-aminoadipic acid, 1,2-butenedicarboxylic acid and elevation of plasma alpha-aminoadipic acid levels. The identity of these metabolities was established by various methods. The excretion of alpha-aminoadipic acid correlated to the lysine intake. Degradation studies with cultured fibroblasts indicate a defect in the oxidative decarboxylation of alpha-ketoadipic acid (see Clin. Chim. Acta, 58 (1975) 271.
A modified method used for the quantitative estimation of LDH-isoenzymes in serum after electrophoresis on cellulose acetate is described. Total LDH-activity and isoenzyme distribution in serum samples of capillary blood are compared to those in samples collected by venipuncture. Total LDH-values and LDH-distributions both in 29 normal children and 14 children with malignant diseases are given. When studying the LDH-distribution in serum samples of children with malignant diseases a significantly decreased LDH-3 was found in many patients. LDH-4 and LDH-5 were also reduced. It was noted that these children all received therapy with prednisone. Possible explanations are discussed.
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