In order to determine the frequency of thyroxine (T4) toxicosis and study the possibility of usefulness for differentiation between thyrotoxic Graves' disease and destructioninduced thyrotoxicosis, the serum concentrations of T4, triiodothyronine(T3), reverse T3 (rT3), and T4-binding globulin (TBG) and the values of T3-uptake and radioactive iodine uptake (RAIU) were measured, and free, T4 inde...

To the Editor: Ultrafiltration is a standard method for separating free T3 and free T4 from serum proteins and proteinbound hormone (1, 2 ). It is expected that free T3 and free T4 in aqueous solutions will accompany water as water moves across semipermeable membranes, a process that results in equal concentrations of free T3 and free T4 in the aqueous solutions on opposite sides of semipermeab...

Background: Hyperthyroidism is much less common in children < 7 years vs. older children and less well studied. It was our impression that the youngest patients needed a higher weight-based dose of methimazole (MMI) to achieve euthyroidism. Objectives: To compare the mean MMI dose needed to normalize free T4 in younger ( < 7 years) vs. older children and the time taken to normalize free T4. Me...

Hormones have to be transported from their sites of synthesis to their target organs. For lipophilic hormones, such as steroids and thyroid hormones, transport is accomplished by binding to specific serum proteins, in the case of thyroxine (T4) and tri-iodothyronine (T3) to thyroxine-binding globulin (TBG) and prealbumin (PA). Normally about 70% of circulating T4 and 7540% of T3 is bound to TBG...

A cell-free system for synthesizing bacteriophage T4 late RNA is described. The system, which is based on the "cellophane disc" technique introduced by Schaller and co-workers (Schaller, H., Otto, B., Nüsslein, V., Huf, J., Hermann, R., and Bonnhoeffer, F. (1972) J. Mol. Biol. 63, 183-200), provides favorable conditions for T4 DNA and RNA synthesis in vitro. Total RNA synthesis can be sustained...

We have designed a re-usable dialysis cell and a complex dialysis buffer, with which undiluted serum samples can be dialyzed with minimal changes in their serum matrix. Dialysate thyroxin (free T4) is then measured by a sensitive RIA for T4. The range of reportability was 2-128 ng/L, the normal range was 8-27 ng/L, and the interassay CV was 7%. Free T4 concentrations in various disorders were a...

PURPOSE Current management for patients with differentiated thyroid cancer includes near total thyroidectomy and radioactive iodine therapy followed by administration of supraphysiological doses of levothyroxine (L-T4). Although hyperthyroidism is a well known risk factor for osteoporosis, the effects of L-T4 treatment on bone mineral density (BMD) in patients with thyroid cancer do not appear ...

A 40-year-old hypothyroid female who had been treated with synthetic thyroxine was admitted to our hospital in October 1988 due to abnormal liver function tests. She had low serum free triiodothyronine (T3; 2.3 pg/ml) and high serum thyrotropin (TSH; 20.8 microU/ml) concentrations. On the other hand, the serum free thyroxine (FT4) level was inappropriately high, being 2.46 ng/dl. Immune precipi...