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Biomedical subjects

S Landaas

Publications and source records attributed to S Landaas.

43 records · Page 3Linked to original sources
PubMed1975

Accumulation of 3-hydroxyisobutyric acid, 2-methyl-3-hydroxybutyric acid and 3-hydroxyisovaleric acid in ketoacidosis.

1. Urine and serum samples from patients with ketoacidosis of varying degree and etiology have been examined by gas chromatography and mass spectrometry. 2. In addition to 3-hydroxyisovaleric acid, relatively high concentrations of two analogous hydroxy acids, 3-hydroxyisobutyric acid and 2-methyl-3-hydroxybutyric acid, were found in the urine. 3. There were highly significant positive correlations between the excreted amounts of the three acids. 4. Experiments on rats with isotope-labelled compounds revealed that the acids were formed by the degradation of leucine, isoleucine and valine. 5. The accumulation of the hydroxy acids during ketoacidosis is probably caused by a similar derangement of the metabolism of all three branched-chain amino acids.

Acetates↗
PubMed1975

The formation of 2-hydroxybutyric acid in experimental animals.

1. The formation of 2-hydroxybutyric acid (2-HB) has been studied by animal experiments. 2. 2-HB was excreted in the urine together with lactic acid following intravenous administration of huge amounts of 3-hydroxybutyric acid (sodium salt) to a dog. 3. Rats made diabetic by an injection of streptozotocin were found to excrete large quantities of 2HB in the urine (up to 300 mumol/24 h) together with the development of ketoacidosis. 4. The use of 14-C-labelled precursors clearly showed that the amino acids methionine, threonine and homoserine can be converted to 2-HB. 5. 2-Aminobutyric acid is also converted to 2-HB, with 2-oxobutyric acid as an intermediate metabolite. The ratio between the urinary concentrations of 2-HB and 2-oxobutyric acid was increased by the ingestion of ethanol. 6. In normal rats neither a prolonged fasting period nor loading with large doses of methionine, threonine and homoserine resulted in the excretion of 2-HB. 7. The mechanisms behind the formation of 2-HB are discussed, and it is concluded that an increased NADH2/NAD ratio in the cytoplasma is the most important factor.

Amino Acids↗
PubMed1975

Clinical conditions associated with urinary excretion of 2-hydroxybutyric acid.

Urine and blood samples from patients with different clinical disorders were examined for 2-hydroxybutyric acid (2-HB) by gas chromatography and mass spectrometry. All patients with combined lactic acidosis and ketoacidosis excreted 2-HB in the urine, in amounts up to 2.3 mmol/mmol creatinine. In blood from these patients, 2-HB was present only in trace amounts. Hard physical exercise resulted in lactic acidosis and accumulation of 2-HB. The lactate to pyruvate ratio in blood and urine was markedly increased in the patients excreting 2-HB but was normal in two patients with lactic acidosis who did not excrete 2-HB. It is concluded that an increased NADH2/NAD ratio is the most important factor for the production of 2-HB.

Acidosis↗