We used various kits to measure free thyroxin (T4) in serum from a patient with the very rare syndrome of euthyroid hyperthyroxinemia secondary to increased thyroxin-binding prealbumin in serum. This patient's free T4 by equilibrium dialysis was 13 ng/L (normal 9-21), whereas the free-T4 index was 18.6 (normal 5.5-11.5). Using six different commercial methods, the last three listed being T4-ana...

Intact gonococci (GC) have been labeled with 125iodine by the lactoperoxidase plus hydrogen peroxide procedure. The specific activities of types 2, 4, and 4 GC have been determined and are found to show small differences as follows: T4 greater than T2 greater than T4. 125I-labeled GC have been studied for their associations with both leukocytes and tissue culture cells. 125I-labeled GCshow the ...

BACKGROUND Thyroxine (T4) hormone is synthesized by the thyroid gland and then released into the systemic circulation where it binds to a number of proteins. Dysfunction in T4 transport mechanisms has been demonstrated in multiple central nervous system (CNS) diseases including Alzheimer's disease. In the presence of different compounds that inhibit potential T4 transport mechanisms, this study...

OBJECTIVE Replacement T4 dose in hypothyroid patients bearing both chronic autoimmune thyroiditis and atypical celiac disease (CD) has been analyzed. DESIGN Replacement T4 dose has been analyzed in 35 hypothyroid patients with Hashimoto's thyroiditis (HT) and atypical CD, as defined by the American Gastroenterological Association. We have evaluated the ability of the same dose of T4 to reach ...

During the course of investigating the regulation of IL-2-dependent T cell proliferation, we found that the subset of human T cells expressing the T4 surface glycoprotein become refractory to IL-2 growth promotion earlier than T8+ cells. Since T4+ cells proliferate in an autocrine fashion to endogenous IL-2, whereas most T8+ cells respond in a paracrine fashion to IL-2 derived from T4+ cells, w...

Various experiments have indicated the presence in whole human serum of three major thyroxine (T4)-binding 1 proteins: T4-binding globulin (TBG), T4-binding prealbumin (TBPA), and albumin (1, 2). It is well established that, in vitro, TBG and TBPA are the major T4-binding proteins, whereas albumin is a relatively weak secondary carrier (3-5). These proteins interact with the hormone in a revers...

Several investigations have reported an increase, in stored serum, in apparent thyroxine (T4) concentration measured by competitive binding radioassay (CPBR) with thyroxine-binding globulin (TBG) as the binding reagent [l-7]. Watson and Lees [4] attributed this increase to the production of a “mimic T4” during storage. Recently, we [6] and Rootwelt [7], working independently, discovered that th...

Changes in plasma thyroxine (T4), triiodothyronine (T3), free thyroxine index (FT4I) and thyroid stimulating hormone were studied in 100 patients with Graves' disease treated with carbimazole. During therapy plasma T3 concentrations were disproportionately high compared to those of T4, the T4 : T3 ratio was low, and many patients were clinically euthyroid with a normal plasma T3 but low T4 conc...