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Biomedical subjects

S G Baird

Publications and source records attributed to S G Baird.

7 recordsLinked to original sources

The effect of intravenous heparin infusions on the thyroid stimulating hormone response to thyrotrophin releasing hormone.

1 The TSH response to TRH is suppressed 24 h after the commencement of i.v. heparin infusion in euthyroid subjects, as compared to repeat testing, both after 7 days of continuous i.v. heparin and after 7 days without heparin but while on warfarin. 2 This suggests that the rise in serum free thyroid hormones, which heparin produces, has a 'metabolic effect'. Possible clinical effects of this action must be considered. 3 Heparin has no effect on the radio-immunoassay of TSH.

Heparin

Discrepancies in thyroxine measurement in pregnancy between radioimmunoassay and competitive protein binding (Oxford StaT4).

The StaT4 test is a technically simple test of thyroxine measurement, which apparently gives results in good agreement with those derived by radioimmunoassay in most patients. In pregnancy, however, falsely low serum thyroxine values were found with the StaT4 test when compared with either a radioimmunoassay or the Thyopac-4 test. Detailed studies showed that the discrepancy resulted from the extraction technique used in the StaT4 test, which appears to allow the patient's thyroxine binding proteins to remain in the assay system. Similar method discrepancies were observed in other clinical conditions associated with elevated thyroxine binding globulin concentration. This study, as well as being of practical clinical importance, has implications for the design of competitive protein binding tests of thyroid function.

Evaluation Studies as Topic

Thyroid function in dietary amenorrhoea.

Abnormalities of thyroid function are well known to occur in anorexia nervosa. A commoner problem is the patient with secondary amenorrhoea due to weight loss, who does not have true anorexia nervosa. Eight such patients were studied and compared to a normal control group. Total and free thyroxine, total and free triiodothyronine were found to be significantly lower in the amenorrhoea patients. No difference in basal thyroid stimulating hormone or reverse triiodothyronine levels were found. In three of four patients who had thyrotrophin releasing hormone tests performed a prolonged response was found. These results indicate that abnormal thyroid function tests may be found in this milder form of the disease. In addition, the normal reverse triiodothyronine levels suggest the possibility of two mechanisms existing, whereby T3 levels may be lowered in nutritional disorders.

Adolescent

Retarded incorporation of [14C]mannose into thyroglobulin of human thyrotoxic thyroid glands.

In vitro studies using thyroid slices from human non-toxic goitres and from thyrotoxic glands show retarded incorporation of [14C]mannose into the 19S protein of thyrotoxic glands. This was not found using [14C]galactose with thyrotoxic glands or using either labelled sugar with slices from non-toxic goitres. Experiments with thyroid tissue from rats on a variety of treatment regimes such as iodine supplements, carbimazole alone or with iodine supplements did not show this differential delay of [14C]mannose incorporation. This suggests that there may be some abnormality of carbohydrate incorporation into thyroglobulin in thyrotoxicosis.

Animals