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Biomedical subjects

R J Truscott

Publications and source records attributed to R J Truscott.

10 recordsLinked to original sources

Studies on a child suspected of having a dficiency in 3-hydroxy-3-methylglutaryl-Co A lyase.

The urine of a child who presented with hyperammonemia was found to contain elevated levels of 3-hydroxy-3-methylglutaric acid, 3-methylglutaconic acid and 3-methylglutaric acid. An increased excretion of these organic acids has been reported previously in a child with 3-hydroxy-3-methylglutaryl-CoA lyase deficiency. Enzyme studies using cultured fibroblasts from this patient, however, indicated that the 3-hydroxy-3-methylglutaryl-CoA lyase activity was not markedly reduced.

Acyl Coenzyme A

Dicarboxylic aciduria: the response to fasting.

The urine of a child who presented with an episode of a disease resembling Reye's syndrome was found to contain large quantities of the dicarboxylic acids adipic and suberic acids, as well as the glycine conjugate of suberic acid, suberyl glycine. A variety of other dicarboxylic acids, both saturated and unsaturated, were also found in the urine at the time of the attack. It was found that the excretion of these unusual metabolites could be markedly increased by fasting for periods of greater than 10 h. These results indicate that the patient may have a defect in fatty acid oxidation which becomes clinically significant during periods of prolonged fasting.

Adipates

The identification of 3-keto-2-methylvaleric acid and 3-hydroxy-2-methylvaleric acid in a patient with propionic acidemia.

Two abnormal metabolites, 3-keto-2-methylvaleric acid and 3-hydroxy-2-methylvaleric acid, have been identified and quantitated in the urine of a child with propionic acidemia. These metabolites may be produced as a result of the self-condensation of propionyl-CoA. Data are presented to show that the unusual ketone, 3-pentanone, which has been observed previously in the urine of patients with propionic acidemia, is produced as a result of the decarboxylation of 3-keto-2-methylvaleric acid.

Gas Chromatography-Mass Spectrometry

Abnormal deoxyribose metabolites in the urine of a child with a possible new inborn error of metabolism.

The urinary extract of a child investigated because of strabismus was found to contain large amounts of a compound which was identified using gas chromatography/mass spectrometry as 2-deoxyerythropentono-1,4-lactone. This lactone has not been observed previously in urinary extracts. When ion-exchange chromatography was used to isolate the organic acids from urine, the major peaks obtained by gas chromatography were shown to be 2-deoxyerythropentonic acid, 2-deoxyerythropentono-1,5-lactone and 2-deoxyerythropentono-1,4,lactone. Another abnormal metabolite, 2-deoxyribitol, was also excreted by the patient although this compound could not be detected in the urine of normal children. It is proposed that these unusual compounds accumulate in the urine of this child as a result of a defect in the catabolism of 2-deoxyribose.

Deoxyribose

Simultaneous determination of diphenylhydantoin, mephobarbital, carbamazepine, phenobarbital and primidone in serum using direct chemical ionization mass spectrometry.

A quantitative method for the simultaneous determination of five anticonvulsants in serum has been developed using chemical ionization mass spectrometry without prior chromatographic separation. The technique was shown to be rapid, simple and sensitive, allowing the routine analysis of 50 microliter of serum with good within-day and day-to-day precision.

Anticonvulsants

Oxidative changes in human lens proteins during senile nuclear cataract formation.

1. Proteins from the cortex and nucleus of the human lens were studied to determine if any changes could be detected in their amino acids during senile cataract formation. 2. Senile nuclear cataract formation was found to be accompanied by a progressive oxidation of cysteine and methionine. The oxidation of methionine and changes in the distribution of the nuclear proteins did not appear to start until about 60% of the cysteine had been oxidized. 3. In the advanced nuclear cataractous lens, about 90% of the cysteine has been oxidized and 45% of the methionine is present as the sulphoxide in the nuclear proteins. The levels of other amino acids appeared to remain constant. 4. Similar, but smaller, changes were found in the cortical proteins in advanced nuclear cataractous lenses, suggesting that the oxidation spreads from the nucleus to the cortex. 5. These changes were discussed with regard to current views on cataract formation and it was concluded that they are probably the result of simple oxidation of the proteins with O2 or H2O2.

Adult