Biomedical subjects
R Hoffenberg
Publications and source records attributed to R Hoffenberg.
A tale of two cultures; do we differ?
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HIV testing on all pregnant women.
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What price academic general practice?
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Medicine and South Africa.
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Serum thyroglobulin concentrations and whole-body radioiodine scan in follow-up of differentiated thyroid cancer after thyroid ablation.
Measurement of serum thyroglobulin (Tg) concentrations and whole-body radioiodine scan were performed simultaneously during follow-up of 32 patients with differentiated thyroid cancer who had undergone thyroid ablation by operation and radioiodine. Almost all patients in whom serum Tg was undetectable had normal scans. Concentrations exceeding 50 ng/ml were invariably associated with residual or metastatic tumour uptake in the scan. Out of 21 observations of detectable values below 50 ng/ml, 14 were in patients whose scans showed subclinical or sub-radiological tumour uptake and seven in patients with normal scans. The sensitivity of serum Tg as a tumour marker compared favourably to that of the whole-body scan. A scan is unnecessary when serum Tg is undetectable, but in patients with detectable serum Tg concentrations, particularly if these are below 50 ng/ml, a scan is important to assess and localise tumour uptake of iodine before advising treatmet with iodine-131.
Relapse after short-term antithyroid therapy of Graves' disease.
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Different measurements of thyroid function in hypothyroid infants diagnosed by screening.
Different measurements of thyroid function including I123 thyroid scanning were performed in 16 hypothyroid infants diagnosed by a TSH screening project. These results were then related to the clinical presentation and the bone age. Although T3 levels were preferentially maintained, it was the best single measure of the severity of hypothyroidism. Thyroglobulin may have a role in the diagnosis of athyrosis. Scanning showed that athyrosis was uncommon (12.5%) but an ectopic gland occurred in 40%, and accounts for many of the less severly affected cases found on screening. Some of these measurements may have prognostic significance.
Peripheral metabolism of hormones: clinical implications.
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The role of thyronine in thyroid hormone metabolism.
Thryonine (T0) has been identified in human urine using gas chromatography-mass fragmentography (G.C.M.F.). In 22 normal individuals urinary T0 concentration was found to range between 8--25 nmol/24h. Assuming the mean normal thyroxine (T4) production rate to be approximately 100 nmol/24h, our findings indicate that less than 20% of this could be accounted for as urinary T0 excretion, thus supporting earlier findings that the peripheral metabolism of T4 is not limited solely to deiodination.
Effects of surgical stress and corticotrophin on the peripheral metabolism of thyroid hormones in rabbits.
The effect of surgical stress and ACTH injection on the peripheral monodeiodination of thyroxine (T4) was studied in the rabbit. These stimuli resulted in a switch from the peripheral formation of tri-iodothyronine (T3) to reverse T3 in normal rabbits and in rabbits whose thyroidal secretion was suppressed by administration of T4. This is analogous to the situation in man. These changes were not due to alterations in the serum binding capacity for thyroid hormones.
Thyroglobulin concentration in neonatal blood: a possible test for neonatal hypothyroidism.
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Relapsing polychondritis: an autoimmune disease?
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The Steve Biko inquest.
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The inter-relationship of thyroid hormones, vitamin A and their binding proteins following acute stress.
The effects of surgical stress on the metabolism of the retinol-binding-protein-thyroxine-binding-prealbumin complex were investigated. The immediate postsurgical period was characterized by a rapid decline in the serum concentration of retinol, retinol binding protein and triiodothyronine and an increase in the 24 h urinary excretion of retinol, retinol-binding-protein and thyroxine. Similar, but less pronounced, changes were seen in other subjects suffering acute myocardial infarction but were not observed in normal healthy euthyroid males or in pre-operative euthyroid patients. The preparation of specific anti-retinol binding protein anti-serum and the use of this in 'monorocket' immunoelectrophoresis are also described.
Concentration of thyroxine-binding globulin: value of direct assay.
The concentration of thyroxine-binding globulin (TBG) in the serum can now be measured by direct assays that are simple and inexpensive. Comparison of a direct measurement of TBG concentration with a widely used indirect method (Thyopac-3) showed that the indirect method was inaccurate when TBG concentrations were high. This will result in an increase in the derived free thyroxine index (FTI), so that euthyroid patients with a raised TBG concentration may be at risk of being labelled thyrotoxic. Correction of serum total thyroxine (T4) concentration according to the actual TBG concentration (T4:TBG ratio) provided a better correlation with thyroid state than FTI.
Metabolism of thyroid hormones by the isolated perfused rabbit kidney.
The metabolism of thyroxine and triiodothyronine in the isolated perfused rabbit kidney was monitored by specific radioimmunoassay for each hormone. The amount of thyroxine catabolised was proportional to the amount added initially and no saturation effects were observed over a wide range (3.9-82 nmol). After addition of thyroxine alone, triiodothyronine could be detected in the perfusion medium within 10 minutes but only much later in the urine. It was proposed that circulating thyroxine contributes indirectly to the level of urinary triiodothyronine.