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Biomedical subjects

N Gregersen

Publications and source records attributed to N Gregersen.

At least 181 records · Page 10Linked to original sources
PubMed1980

Excretion of short-chain N-acylglycines in the urine of a patient with D-glyceric acidemia.

Five urine samples were collected in clinically quiet periods over a period of one year from a patient suffering from D-glyceric acidemia, and investigated for presence or absence of glycine-conjugates. The findings of isovalerylglycine, 2-methylbutyrylglycine, isobutyrylglycine, and tiglylglycine are interpreted as indications of intracelluar accumulations of isovaleryl-CoA, 2-methylbutyryl-CoA and isobutyryl-CoA. Similarly, the findings of elevated amounts of butyric acid and hexanoic acid together with butyrylglycine, hexanoylglycine, and suberic acid suggest intracellular accumulations of straight-chain acyl-CoA's. It is therefore suggested that this child has a common derangement in his acyl-CoA dehydrogenase (in addition to his primary defect). As possible secondary consequences of this, two points can be mentioned: firstly hyperglycinemia, from which the patient suffered, and secondly, diminished tendency to ketosis, a condition from which the child never suffered, not even in connection with severe intercurrent disease.

Amino Acid Metabolism, Inborn Errors↗
PubMed1980

Medium-chain triglyceride medication as a pitfall in the diagnosis of non-ketotic C6-C10-dicarboxylic acidurias.

Four children and one adult who received medium-chain triglycerides of C6-C10 chain length excreted substantial amounts of C6-C10-dicarboxylic acids in the urine. It has become increasingly common to treat children suspected of malabsorption with preparations containing medium-chain triglycerides, and attention is drawn to the danger of confusing the dicarboxylic aciduria seen in these children, with that seen in metabolic defects due to a possible failure in the beta-oxidation of fatty acids.

Adult↗
PubMed1980

Non-ketotic C6-C10-dicarboxylic aciduria: biochemical investigations of two cases.

Two boys, who are not related, with hypoglycemia and C6-C10-dicarboxylic aciduria were investigated. Besides substantial amounts of adipic, suberic and sebacic acids, the urinary metabolic profile of organic acids contained 5-OH-caproic acid and caproylglycine. During acute attacks the concentrations of adipic, suberic and sebacic acids were 300--530, 160--200 and 35--200 micrograms/mg creatinine, respectively, and the excretions of 5-OH-caproic acid and caproylglycine were 75--330 and 41--260 micrograms/mg creatinine, respectively. It is argued that the biosynthesis of adipic acid passes through an omega-oxidation, that the production of 5-OH-caproic acid is caused by an omega-1-oxidation, and that caproylglycine formation passes through a glycine-N-acylase catalysed conjugation of accumulated caproic acid in the patients. Suberic acid and sebacic acid are in the same way omega-oxidation products of accumulated caprylic acid and capric acid, respectively. From the excretion pattern presented it is hypothesized that the patients suffer from a defect in the dehydrogenation of fatty acids in the beta-oxidation pathway. The biological significance of the findings is discussed.

Adipates↗
PubMed1980

Excretion pattern of branched-chain amino acid metabolites during the course of acute infections in a patient with methylmalonic acidaemia.

A 1-year-old boy with a typical B12-responsive form of methylmalonic acidaemia was hospitalized twice due to acute bacterial infections. On both occasions, the child was lethargic with a severe ketoacidosis on admission. Intensive therapy with protein restriction, intravenous administration of electrolytes and antibiotics was effective within 4 days on both occasions. The urinary excretion of organic acids showed the same pattern on both occasions. There were rising excretion concentrations, reaching a peak value within the first 24-hour period, for the following compounds: 3-hydroxybutyric acid, 3-hydroxypropionic acid, 3-hydroxyisobutyric acid and 3-hydroxyisovaleric acid. Excretion concentrations of the following rose for 48 h: isobutyric acid, 2-methylbutyric acid, isovaleric acid, lactic acid and the 2-oxo-acids. There was no increase until 12-24 h after the onset of severe illness in the excretion of propionic acid and methylmalonic acid. Propionic acid excretion was maximal at about 48 h, while peak excretion of methylmalonic acid was delayed until about 72 h after the onset of severe illness; at this time there was clinical improvement. The biochemical implications of this excretion pattern are discussed.

Acute Disease↗
PubMed1980

Biochemical studies in a patient with defects in the metabolism of acyl-CoA and sarcosine: another possible case of glutaric aciduria type II.

The clinical and biochemical abnormalities in a neonate, who died in coma accompanied by severe hypoglycaemia at the age of 3 days, are described. The study of the urinary metabolic profiles of organic acids and amino acids revealed that the excretion rates of glutaric acid, isovaleric acid, isovalerylglycine, 3-hydroxyisovaleric acid and isobutyric acid were very high. Increased excretion rates were also found for 2-methylbutyric acid, adipic acid, caproylglycine, 5-hydroxycaproic acid, caproic acid and butyric acid. The amino acid, sarcosine, was excreted in enhanced amounts and the patient had lactic aciduria, whereas the excretion of 3-hydroxybutyric acid was only moderately increased. This abnormal excretion pattern is consistent with a defect in the metabolism of acyl-CoAs and sarcosine. Normal activity of glutaryl-CoA dehydrogenase was found, excluding glutaryl-CoA dehydrogenase deficiency (glutaric aciduria type I).

Acyl Coenzyme A↗
PubMed1979

N-acylglycines: gas chromatographic mass spectrometric identification and determination in urine by selected ion monitoring.

Eleven biologically interesting N-acylglycines have been synthesized and the gas chromatographic and mass spectrometric properties of their trimethylsilyl derivatives studied, A sharp and reproducible gas chromatographic peak could be obtained for each N-acylglycine as the N, O-bis-(trimethylsilyl)-N-acylglycine. By the use of these derivatives a sensitive and specific selected ion monitoring method for the determination of N-acylglycines in human urine has been developed.

Gas Chromatography-Mass Spectrometry↗
PubMed1979

Treatment of glutaryl-CoA dehydrogenase deficiency (glutaric aciduria). Experience with diet, riboflavin, and GABA analogue.

The autosomal recessive inherited disorder glutaryl-CoA dehydrogenase deficiency (glutaric aciduria) runs a progressive course with severe choreoathetosis and dystonia, eventually leading to total helplessness and early death. Theree patients were observed during therapeutic trials with a protein-low diet, riboflavin and GABA analogue. Diet and riboflavin had a slight-to-moderate effect on the clinical symptoms; the excretion of glutaric acid and 2-amino-adipic acid decreased considerably during treatment. Regression of neurologic symptoms was observed during treatment with GABA analogue. It is concluded that the patients should be treated as early as possible with protein-low diet, riboflavin, and GABA analogue.

2-Aminoadipic Acid↗
PubMed1979

The excretion of C6-C10-dicarboxylic acids in the urine of newborn infants during starvation. Evidence for omega-oxidation of fatty acids in the newborn.

The excretion of C6-C10-dicarboxylic acids, i.e. adipic, suberic and sebacic acids, was measured during the three first days of life in 3 fasting newborns, 2 newborns fed with isocaloric glucose and 2 newborns given mothers'-milk. On the second and third day of life the starved children excreted 27-84 mmol adipic acid/mol creatinine, 6-22 mmol suberic acid/mol creatinine and 4-7 mmol sebacic acid/mol creatinine. The excretion of C6-C10-dicarboxylic acids in the neonates given glucose or mothers'-milk was, for the first three days of life, 0-9 mmol adipic acid/mol creatinine, 0-10 mmol suberic acid/mol creatinine and 0-4 mmol sebacic acid/mol creatinine. The latter amounts are equivalent to the excretion of dicarboxylic acids in older children. It is argued that the detected dicarboxylic acids are formed by omega-oxidation of long-chain monocarboxylic acids followed by beta-oxidation, and that the excreted amounts reflect omega-oxidation activity. It is speculated that the substantial omega-oxidation activity in the starving newborn serve to provide succinyl-CoA-substrate for the citric acid cycle and for gluconeogenesis.

Adipates↗
PubMed1979

Studies on the effects of saturated and unsaturated short-chain monocarboxylic acids on the energy metabolism of rat liver mitochondria.

The effect of eight branched-chain amino acid metabolites, four metabolites from the beta-oxidation, and the unphysiologic acid 4-pentenoic acid on the oxygen consumption rate of liver mitochondria oxidizing pyruvate, 2-oxo-glutarate, and L-palmitoylcarnitine has been investigated. The 12 metabolites are: propionic, isobutyric, 2-Me-butyric, isovaleric, acrylic, Me-acrylic, tiglic, Me-crotonic, butyric, hexanoic, crotonic, and 2-hexenoic acids. The oxidation rate of pyruvate was strongly inhibited by propionic, 4-pentenoic, and isovaleric acids at 0.1, 0.1, and 1.0 mM, respectively. With 2-oxo-glutarate as substrate, the oxygen consumption rate was strongly inhibited at 0.1 mM of propionic, 4-pentenoic, and isovaleric acids. The L-palmitoyl-carnitine oxidation rate was very strongly inhibited by 0.1 mM 4-petenoic acid, whereas butyric and hexanoic acids exerted a moderate inhibition at 0.1 mM. Propionic acid inhibited L-palmitoylcarnitine oxidation slightly at 1.0 mM. It is argued that propionyl-CoA and isovaleryl-CoA inhibit pyruvate and 2-oxo-glutarate dehydrogenases directly, and the significance of the results for ketotic episodes in organic acidurias is discussed.

Amino Acids, Branched-Chain↗
PubMed1978

Gas chromatographic mass spectrometric identification of N-dicarboxylmonoglycines.

A number of N-dicarboxylmonoglycines of biological interest have been synthesized. They were characterized by means of mass spectrometry. Gas chromatography of the methyl esters of methylmalonyl-, succinyl-, glutaryl-, adipyl-, suberyl- and sebacylglycines showed a single sharp peak for each compound on Dexsil 300 and OV-17 columns. Methylene unit values and mass spectra of the six methyl esters are reported.

Chromatography, Gas↗
PubMed1978

Glutaric aciduria in progressive choreo-athetosis.

The clinical symptoms in a 10-year-old girl with progressive dystonic cerebral palsy are described. The biochemical findings were dominated by large amounts of glutaric acid in the urine. The disorder is caused by impairment of the degradation of glutaryl-CoA. A survey is given of the clinical and biochemical symptoms, based on the five cases reported so far. It is concluded that patients with progressive dystonic palsy should be examined for disorders in the metabolism of organic acids.

Acyl Coenzyme A↗
PubMed1977

Demonstration of N-dicarboxyl-mono-glycines in dicarboxylic acidurias by mass fragmentography.

Urine samples from 18 individuals with various types of dicarboxylic acidurias have been investigated by mass fragmentography for N-dicarboxyl-mono-glycines (dicarboxylglycines). One patient with methylmalonic acidemia excreted 14-20 microgram methylmalonylglycine/mg creatinine, three patients with glutaric aciduria excreted 20-60 microgram glutarylglycine/creatinine, and one patient with C6-C10-dicarboxylic aciduria excreted 120-365 microgram succinylglycine/mg creatinine. Excretion of C6-C10-dicarboxylic acids in patients with ketosis and glycogenosis and in neonates were not accompanied by excretion of C8-C10-dicarboxylglycines in measurable amounts (greater than 1 microgram/mg creatinine). Nor did patients with succinic aciduria excrete succinylglycine in amounts larger than 1 microgram/mg creatinine. On the basis of these data it is argued that production of short- and medium-chain dicarboxylglycines is not a metabolic pathway of biological significance for the elimination of short- and medium-chain dicarboxylic acids from individuals with dicarboxylic acidurias.

Adolescent↗