OBJECTIVE To determine a levothyroxine (T4) dose recommendation for the treatment of autoimmune thyroiditis (AIT)-induced hypothyroidism. METHODS T4 doses in 75 children and adolescents with newly diagnosed AIT were prospectively collected and compared to T4 doses of patients with congenital hypothyroidism (CH, n=22). RESULTS Sixty-four patients with AIT and 22 patients with CH were include...

Serum free thyroxin (FT4) was determined in 40 patients with various nonthyroidal illnesses. We studied seven methods: (1) a free thyroxin index calculated from total T4 and triiodothyronine resin uptake; (2) a free T4 index determined by enzyme inhibitor assays (Abbott's "Tetrazyme" and "Thyrozyme"); (3) a free T4 index calculated from total T4 and thyroxin-binding globulin; (4) free T4 by equ...

Excessive bias and imprecision are major analytical problems associated with some assays for free and total thyroxine (T4). Bias in free T4 methods is largely proportional to variations in serum T4 binding. In direct methods, this is attributable to requirements for substantial quantities of protein-bound T4 to replace analytical losses of free T4. In some total T4 methods, bias is inversely pr...

We have assessed the influence of albumin-bound thyroxin (T4) on apparent free T4 values obtained by two "unbound analog" free T4 methods (AmerlexR Free T4 and Clinical Assays one-step Free T4). We evaluated sera showing three different albumin anomalies: total hereditary analbuminemia, partially corrected analbuminemia, and familial dysalbuminemic hyperthyroxinemia, where abnormal albumin-bind...

t4 and t3, two major hormones of thyroid gland, are responsible for regulation of “basal metabolism” in the body. thyroid function is regulated primarily by variation in the pituitary tsh. in this study, about four hundred individuals were considered from four iranian populations. they were selected randomly in their cities; shiraz, mashhad, rasht, and ilam. essential family information was ask...

The effects of thyroid hormone analogues on modulation of angiogenesis have been studied in the chick chorioallantoic membrane model. Generation of new blood vessels from existing vessels was increased 3-fold by either l-thyroxine (T4; 10(-7) mol/L) or 3,5,3'-triiodo-l-thyronine (10(-9) mol/L). T4-agarose reproduced the effects of T4, and tetraiodothyroacetic acid (tetrac) inhibited the effects...

The nervous system is dependent upon thyroid hormones for normal development, and we previously reported that developmental Aroclor 1254 (A1254) exposure caused hypothyroxinemia, hearing loss and other behavioral changes in rats. (Goldey et al., 1995a; Herr et al., 1996). The hypothesis that A1254-induced hypothyroxinemia may have contributed to the observed functional changes was tested in pri...

BACKGROUND A recent randomized controlled trial suggests that hypothyroid subjects may find levothyroxine (l-T4) and levotriiodothyronine combination therapy to be superior to l-T4 monotherapy in terms of quality of life, suggesting that the brain registered increased T3 availability during the combination therapy. HYPOTHESIS Peripheral tissue might also be stimulated during T4/T3 combination...

1Department of Chemistry, Rutgers University, Camden, NJ, USA; Center for Computational and Integrative Biology, Rutgers University, Camden, NJ, USA 2Johns Hopkins Bloomberg School of Public Health, Center for Alternatives to Animal Testing (CAAT), Baltimore, MD, USA 3National Toxicology Program Interagency Center for the Evaluation of Alternative Toxicological Methods, National Institute of En...

We have identified an individual whose thyroxine (T4) concentration was undetectable with Abbott's fluorescence polarization immunoassay (FPIA) but within the reference range by radioimmunoassay or EMIT (Syva). The patient's thyrotropin, triiodothyronine, and T-uptake values were within the normal range. The T4 concentration measured by FPIA increased to normal when the immunoglobulin fraction ...