Biomedical subjects
Publications and source records attributed to U Wendel.
In 62 blood samples from 3 patients with classical maple syrup urine disease and from one patient with a variant form, a close linear correlation was found between levels of branched chain amino acids and their corresponding alpha-keto acids. Keto acids were determined as O-trimethylsilyl quinoxalinols by gas chromatography with a nitrogen-selective detector.
Explore the source record for details and available documents.
The course of pyruvate dehydrogenase deficiency in an infant is described. During pregnancy fetal movements were reduced, and since birth severe neurologic involvement was noticed. Permanent metabolic acidosis due to lactic acidemia as well as hyperpyruvic acidemia and hyperalaninemia were present. Alanine accumulated in CSF and urine, urinary excretion of lactate and pyruvate was highly elevated. Pyruvate dehydrogenase activity in a liver biopsy was only 5% of that for normal controls, and pyruvate decarboxylation by cultured fibroblasts was equally decreased. Therapy required permanent administration of bicarbonate. The administration of thiamine had no effect. The infant died within three months. Recently prenatal diagnosis during a subsequent pregnancy of the mother revealed normal results when pyruvate degradation with cultured amniotic fluid cells was investigated, and a healthy child was born.
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.
Explore the source record for details and available documents.
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.
Observation of one patient with alpha-ketoadipic aciduria initiated degradation studies with radiolabelled lysine metabolites in fibroblasts in order to localise the metabolic defect. Liberation of 14-CO-2 from alpha-D,L-(1-14-C) aminoadipate and alpha-(1-14-C) ketoadipate was considerably less in the patient's fibroblasts than in the patient's fibroblasts than in normal controls, whereas 14-CO-2 production from (1,5-14-C) glutarate was in the normal range. These results indicate a defect in the oxidative decarboxylation of alpha-ketoadipate as the probable cause of alpha-ketoadipic aciduria; Cultured amniotic fluid cells from pregnancies of the 15th and 16th week of gestation degrade alpha-(1-14-C) ketoadipate with a similar activity to fibroblast cultures from normal humans after birth.
Kinetic data are presented for the decarboxylation of branched chain alpha-ketoacids (BCKA) by intact human fibroblasts. Cultured cells of normal individuals and nine patients with different clinical pictures of maple syrup urine disease (MSUD) are studied with both alpha-ketoisocaproic acid (2-oxo-4-methylpentanoic acid (KIC)) and alpha-ketoisovaleric acid (2-oxo-3-methylbutanoic acid (KIVA)) as substrates. One normal cell strain and one patient cell strain is analyzed with alpha-keto-beta-methyl-n-valeric acid (2-oxo-3-methylpentanoic acid (MEVA)) as a substrate. A biphasic degradation kinetic for each BCKA is obtained for normal control subjects. The component with higher substrate affinity is affected in MSUD: for KIC the normally hyperbolic substrate curve is changed to sigmoid shape, for KIVA and MEVA as substrates this component is not detectable at all. Considering qualitative aspects of the BCKA decarboxylation kinetics intact fibroblasts yield the same results as our recent studies with the decarboxylase moieties of partially purified kidney BCKA dehydrogenase of normal individuals and one patient with classic MSUD (27). The decarboxylation velocities for normal and patient fibroblasts with one exception differ widely at low but not at high substrate concentrations of BCKA. To get meaningful data on the residual substrate degradation activities with intact fibroblasts of different phenotypes of MSUD physiologically low substrate concentrations are required in the assay.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.