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Biomedical subjects

B E Clayton

Publications and source records attributed to B E Clayton.

15 recordsLinked to original sources
PubMed1979

Changing incidence of neonatal hypermethioninaemia: implications for the detection of homocystinuria.

The Guthrie test was used to measure blood methionine concentrations in 670 764 neonates during the period from May 1970 to December 1977. Raised values (greater than 4 mg/100 ml; 268 mumol/l) were found in 147 babies (6--14 days old) and 55 of these still had raised values when retested 2--6 weeks later. 48 infants had transient hypermethioninaemia of at least 3 weeks' duration, one had a more persistent form associated with abnormal liver function tests, 3 had different forms of homocystinuria, and one infant, who was asymptomatic at the time of detection, had hypermethioninaemia associated with a rapidly fatal form of tyrosinamiea (tyrosinosis). Two infants could not be followed up. Transient hypermethioninaemia has not been detected in this laboratory since 1975. There was a greatly reduced incidence of transient hypermethioninaemia in girls after 1972 and in boys after 1975; this may have been due to recent changes in infant practices in the UK. Homocystinuria was last detected in this laboratory in 1972; the apparent change in incidence is significant (P less than 0.05) and suggests that the diagnostic value of this screening procedure should be reassessed.

Amino Acid Metabolism, Inborn Errors↗
PubMed1978

Pyridoxol metabolism in vitamin B6-responsive convulsions of early infancy.

As there is uncertainty about the nature of the metabolic defect in vitamin B6-responsive convulsion, certain aspects of pyridoxol metabolism were studied in 3 patients who were believed on clinical grounds to have the condition. The findings were compared with those in healthy children and adults, and in children with mental handicap. The magnitude of the initial rise and the subsequent fall in plasma pyridoxal phosphate (PALP) concentrations after a load of pyridoxol suggested that the vitamin B6-responsive patients were able to synthesise PALP normally but were unable to maintain the prolonged high levels normally found in plasma. The urinary excretion of 4-pyridoxic acid was within normal limits, but the excretion of pyridoxol after the load was raised. It is suggested that there may be an instability of the PALP-albumin complex in this condition. Some of the biochemical features were also observed in an infant presenting with convulsions soon after birth but without evidence of clinical B6-dependency.

Adult↗
PubMed1978

Mineral and trace metal supplement for use with synthetic diets based on comminuted chicken.

Earlier studies (Alexander et al., 1974; Lawson et al., 1977) suggested a suitable composition for a mineral and trace metal supplement for use with synthetic diets containing some natural food. Such a mixture has been evaluated in patients receiving a diet based on comminuted chicken and has been shown to be adequate. This conclusion was based on balance experiments measuring Zn, Cu, Mn, Fe, Ca, Mg, N, and P.

Animals↗
PubMed1977

Evaluation of a new mineral and trace metal supplement for use with synthetic diets.

In an earlier study (Alexander et al., 1974) it was shown that the mineral mixture used in association with a synthetic diet was deficient in zinc, copper, iron, and manganese. A new mixture containing appropriately increased amounts of these trace metals has now been evaluated by means of metabolic balance studies carried out on children with phenylketonuria. This new mixture was shown to be satisfactory for zinc, copper, and iron, but minor changes have been recommended for manganese.

Child↗
PubMed1976

Hormonal changes in thalassaemia major.

Patients with severe thalassaemia major suffer endocrine and other abnormalities before their eventual death from iron overload due to repeated blood transfusions. The endocrine status of 31 thalassaemic patients aged 2-5 to 23 years was investigated. Exact data were available on the rate and duration of blood transfusion in all of them and in many the liver iron concentration was also known. Although the patients were euthyroid, the mean serum thyroxine level was significantly lower, and the mean thyrotrophic hormone level significantly higher, compared with the values found in normal children. Forty oral glucose tolerance tests with simultaneous insulin levels were performed in 19 children, of whom 5 developed symptomatic diabetes and one had impaired tolerance. Previous tests on all 6 patients were available and some showed raised insulin levels possibly due to insulin resistance. 2 patients had clinical hypoparathyroidism and are described. The parathyroid hormone levels determined by radioimmunoassay in 25 patients were below the mean for the age group in all and outside the reference range in 16. Nonfasting plasma calcium levels were not reduced. Puberty was delayed in some patients. Concentrations of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) measured in urine from 7 girls and 5 boys showed considerable variation. In the boys there was an overall tendency for FSH and LH excretion to be low with regard to age, but with respect to puberty rating FSH exretions were normal or low and LH normal or raised. The girls showed a tendency for LH but not FSH excretion to be raised in relation to puberty rating. The severity of the endocrine changes was related to the degree of iron loading and is discussed in relation to previous work in which the iron loading has rarely been accurately indicated nor parathyroid status assessed.

Adolescent↗
PubMed1975

Use of biochemical profile in children's hospital: results of two controlled trials.

Two controlled trials of the use of a biochemical profile were conducted in a childern's hospital to see whether the profile led to diagnoses which would not otherwise [have been made and to see what effect it had on the number of extra requests for pathololgical investigations and the length of stay in hospital]. Altogether 2816 children were examined and 13 new diagnoses made. There was a significant increases in the total number of pathorequests but the profile did not alter the length of stay in hospital. We conclude that the profile mad only a small contribtuion to the overall care of the pateints.

Alkaline Phosphatase↗
PubMed1975

New variant of phenylketonuria with progressive neurological illness unresponsive to phenylalanine restriction.

Three children, two of them siblings, with an unusual type of phenylketonuria are described. The three patients, two of them observed from the neonatal period, had a progressive neurological illness which was unlike that of classical phenylketonuria, and which did not respond to a low phenylalanine diet. The biochemical features suggested that the block in the conversion of phenylalanine to tyrosine was less severe than in the classical disease, and phenylalanine rho-hydroxylase activity, measured in one patient was normal. It is suggested that the patients have a disorder of biopterin metabolism possibly due to a defect of the enzyme dihydropteridine reductase.

Biopterins↗
PubMed1975

Comparison of an amino acid mixture and protein hydrolysates in treatment of infants with phenylketonuria.

This study compares three feeding regimens for infants with phenylketonuria diagnosed by neonatal screening. Group 1 (five children) received Minafen (Cow & Gate) until they weighed twice their birthweights; Aminogran (Allen & Hanbury) was then added to the feeds in increasing amounts and replaced Minafen at between 8 and 10 months of age. Group 2 (five children) received Aminogran from the neonatal period. Group 3 (five children) received Minafen until they weighed twice their birthweights; Cymogran (Allen & Hanbury) was then added in increasing amounts and replaced Minafen at between 8 and 10 months of age. In all three groups growth was normal and control of phenylalanine levels satisfactory. During the first few months of life the Aminogran regimen proved more complicated and caused more practical difficulties than the regimens starting with Minafen. Later in the first year, when mixed feeding was introduced, and particularly when the bottle was exchanged for the cup, Aminogran had advantages over Cymogran because of its low calorie content, small bulk, and less unpleasant taste. At this age feeding problems were fewer and easier to manage with Aminogran than with Cymogran. A method of using Aminogran in the management of such problems is described. For these reasons, the regimen fed group 1, in which Minafen is used initially and then replaced by Aminogran, is preferred to the other two.

Alkaline Phosphatase↗