Biomedical subjects
Publications and source records attributed to M Duran.
The isolation, identification, and quantitative determination of an unusual urinary dipeptide, Nepsilon-(beta-aspartyl)lysine, is described, as well as its synthesis. This compound was observed in children in various disease states, but without any correlation with a particular symptom. Its origin is discussed.
Random urine samples from eight patients with propionicacidaemia were analyzed by gas chromatography and mass spectrometry in order to see if a consistent metabolite pattern with a high diagnostic value could be found. However, wide variations were observed. The presence of 3-hydroxypropionate and/or methylcitrate were considered to be diagnostic of propionyl-CoA carboxylase deficiency. In addition, samples from ketotic periods frequently contained 3-hydroxy-n-valerate and 3-oxo-n-valerate.
A child is described who presented in the neonatal period with feeding difficulties, severe neurological abnormalities, lens dislocation of the eyes and dysmorphic symptoms of the head. Routine laboratory investigations revealed a decreased serum urate and a positive sulphite reaction of the urine. Subsequent chromatographic examinations showed xanthinuria and increased excretion of S-sulphocysteine and taurine to be present. In addition, high thiosulphate and low sulphate excretions in the urine were observed. Xanthine oxidase deficiency was demonstrated in a jejunal biopsy specimen, whereas the excretion of sulphur containing substances was considered to be characteristic of sulphite oxidase deficiency. This new combination of defects may be the result of malfunctioning of both enzymes, possibly caused by alterations in the essential molybdenum containing active centre of the enzymes, which they share in common.
Two patients with methylmalonic acidaemia due to methylmalonyl-CoA mutase deficiency were studied for several years. Both exhibited at least two attacks of severe ketoacidosis, during which they excreted, in addition to methylmalonic acid, a number of abnormal compounds: 3-hydroxypropionic acid, 2-methyl-3-hydroxybutyric, 3-hydroxy-n-valeric acid, 3-oxo-n-valeric acid, 2-methyl-3-oxobutyric acid, citraconic acid and N-tiglyglycine. These compounds represent partly intermediary metabolites from the isoleucine degradation pathway and partly secondary metabolites of propionyl-CoA and tiglyl-CoA.
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A boy with the intermediate variant of branched-chain ketoaciduria was studied. Treatment with an amino acid mixture was discontinued at the age of 7.5 years. Reintroduction of normal protein-containing foods precipitated the biochemical abnormalities, characteristic of MSUD, which were relieved by 10 mg thiamine/day. Adaptation to this regiment developed and thiamine intake was increased to 100 mg/day, later to 1 000 mg/day. The patient developed well and had no attacks of ketoacidosis. 1-14C-leucine degradation in intact fibroblasts was 15% of controls and did not increase upon addition of thiamine to the incubation medium.
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An unknown acidic compound was detected in a number of urine samples from patients with a suspected metabolic disorder and some patients treated with chemotherapy. The structure of this compound has been characterized as (2-ethoxyethoxy)acetic acid, using a gas chromatography/mass spectrometry/computer system. The authentic compound was synthesized and compared with the unknown. Urinary (2-ethoxyethoxy)acetic acid is assumed to be formed endogenously from an exogenous precursor, probably 2-(2-ethoxyethoxy)ethanol.
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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.
A sterotaxic device for experimental surgery in enucleated eyes is described. This instrument is made entirely of plastic, is inexpensive to make, and has proved to be an invaluable help in teaching microsurgical procedures to ophthalmic residents.
From their experimental findings in 120 rabbits, the authors conclude that, at first, cholecystitis is usually an aseptic lesion and infection occurs only secondarily. In a large number of cases the initial physiopathological mechanism is that of inflammation which may be due to mechanical causes such as obstruction of the gall bladder siphon and vasomotor phenomena under autonomic control. The histological lesions and course are comparable to those observed in clinical medicine. The interest of this experimental study is to compare the pathology of acute cholecystitis with pancreatitis and Reilly's syndrome and Gregoire and Couvelaire's theory of visceral apoplexy.
A further case of juxta-cortical chondroma in the first finger-ray of a 61-year-old woman. Periosteal chondroma is an extremely rare benign tumor. Only 34 cases can be found in the literature. The tumor is cured with surgical removal.
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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.