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Biomedical subjects

A Fairney

Publications and source records attributed to A Fairney.

9 recordsLinked to original sources

Hypercalcaemia in rheumatoid arthritis: investigation of its causes and implications.

When correction was made for hypoalbuminaemia, 23 of 50 ambulant patients with definite or classical rheumatoid arthritis were found to have hypercalcaemia. When these 23 patients were studied 6 months later, 7 had hypercalcaemia as defined by the correction factor for a low serum albumin level, and 6 of these patients had raised serum ionised calcium concentrations. Biochemical studies in the 23 patients indicated evidence of hyperparathyroidism, namely, hypophosphataemia, increased serum alkaline phosphatase, hyperchloraemia, and reduced tubular reabsorption of calcium. However, serum immunoreactive parathyroid hormone concentrations were normal. Only one patient had an abnormally low serum 25-hydroxy-vitamin D result: this patient had a high level of urinary D-glucaric acid and was receiving phenobarbitone for treatment of epilepsy. The biochemical features suggestive of parathyroid overactivity were particularly found in patients with raised serum calcium levels. The cause of hypercalcaemia in rheumatoid arthritis remains to be explained.

Adult

The effect of darkness on vitamin D in adults.

Circulating 25-hydroxy vitamin D measurements were made on Caucasians in the Antarctic. Following a period of 3 months' complete darkness there was a significant fall in 25-hydroxy vitamin D values. These results emphasize the importance of u.v. light on skin synthesis of cholecalciferol and support the view that the geriatric and immigrant population should be adequately exposed to sunlight to prevent vitamin D deficiency.

Adult

A simple micromethod for 25-hydroxyvitamin D estimation.

A quick and simple method for estimating 25-hydroxyvitamin D is described, It involves dichloromethane extraction followed by competitive protein-binding assay without chromatography. This assay can be performed on 100 microliter of serum and enables 50 samples to be estimated in one working day. The simplicity, speed, and sample size of this method make it very suitable for use in a routine clinical biochemistry laboratory. It is particularly useful when calcium disorders secondary to abnormalities in vitamin D intake and metabolism are suspected.

Animals

Vitamin D and human lactation.

Circulating serum-25-hydroxyvitamin-D concentration was measured in recently delivered mothers who were breast-feeding and in those who were not. 4-6 weeks' lactation produced no significant change. Basal and 4-6-week values in the breast-feeding group were significantly higher than in those who were not breast-feeding. There was no evidence that lactation was an indication for supplementary vitamin D.

Asia

Current status of vitamin D metabolism.

In summary one can record that the biochemist has discovered a beautiful metabolic pathway for vitamin D which is probably as yet incomplete. Subsequently the medicinal chemist has provided numerous synthetic analogues. However, delays in the diagnosis and treatment of vitamin D disorders, due to lack of specific assays and inadequate supplies of therapeutic metabolites, still unfortunately exist. It is hoped that these problems will be rectified as soon as more plentiful supplies of the appropriate metabolites are available.

Calcium Metabolism Disorders

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