Background: We present a large European populationbased study of thyroid function, performed in a population with longstanding borderline sufficient iodine intake. Methods: The Nijmegen Biomedical Study is a population-based survey conducted in the eastern part of The Netherlands. Randomly selected inhabitants received a postal questionnaire on lifestyle and medical history, which was filled out by 9371 individuals (41.7%). We measured serum thyroid-stimulating hormone (TSH), free thyroxine (FT 4 ), and anti-thyroperoxidase antibodies (TPOAbs) in 6434 responders. A reference population of 5167 individuals was selected by excluding those at risk for thyroid disease. Results: Overt thyrotoxicosis was found in 0.4% of the total population and subclinical thyrotoxicosis in 0.8%. Overt hypothyroidism was found in 0.4% and subclinical hypothyroidism in 4.0%. In individuals older than 60 years, mean FT 4 concentrations increased with age. Mean TSH decreased with age, from 1.46 mIU/L at 18 -24 years to 1.07 mIU/L after 85 years. The mean TSH in the total population did not differ from the mean TSH in the reference population; the exclusion of those at risk for thyroid disease, however, lowered the upper limit of the TSH reference interval considerably. In the total

Hypothyroxinemia and TPOAb positivity are associated with an increased risk of premature delivery. The increased risk in TPOAb-positive women seems to be independent of thyroid function.

Background: Quantification of plasma free metanephrine (MN) and normetanephrine (NMN) is considered to be the most accurate test for the clinical chemical diagnosis of pheochromocytoma and follow-up of pheochromocytoma patients. Current methods involve laborious, time-consuming, offline sample preparation, coupled with relatively nonspecific detection. Our aim was to develop a rapid, sensitive, and highly selective automated method for plasma free MNs in the nanomole per liter range. Methods: We used online solid-phase extraction coupled with HPLC-tandem mass spectrometric detection (XLC-MS/MS). Fifty microliters plasma equivalent was prepurified by automated online solid-phase extraction, using weak cation exchange cartridges. Chromatographic separation of the analytes and deuterated analogs was achieved by hydrophilic interaction chromatography. Mass spectrometric detection was performed in the multiple reaction monitoring mode using a quadrupole tandem mass spectrometer in positive electrospray ionization mode. Results: Total run-time including sample cleanup was 8 min. Intra-and interassay analytical variation (CV)

Context:In male patients with congenital adrenal hyperplasia (CAH), testicular adrenal rest tumors are frequently found that may interfere with gonadal function.Objective: Our objective was to determine steroid-producing features of testicular adrenal rest tumors. Design and Setting:The study is descriptive and took place at a university medical center. Patients:Eight adult CAH patients with bilateral testicular adrenal rest tumors were treated with testis-sparing surgery. Interventions:In all but one patient, spermatic veins were cannulated during surgery and blood samples collected to measure the adrenal-specific steroid 21-deoxycortisol (21DF) and 17-hydroxyprogesterone (17OHP) and androstenedione (A). The same parameters were measured in simultaneously taken peripheral blood. mRNA concentrations of adrenal-specific enzymes CYP11B1 and CYP11B2 and ACTH and angiotensin II (AII) receptors were measured in tumor tissue. Main Outcome Measures:Adrenal-specific steroids/enzymes were assessed.Results: 21DF, 17OHP, and A levels were measurable in all spermatic vein samples. The ratio (mean Ϯ SD) between spermatic vein and simultaneously taken peripheral blood samples was 37.8 Ϯ 56.3 (21DF), 132.0 Ϯ 249 (17OHP), and 57.0 Ϯ 68.2 (A). CYP11B1, CYP11B2, and ACTH and AII receptor mRNAs were detected in all tumors with a strong correlation between ACTH receptor mRNA in tumors and 21DF (r ϭ 0.85; P ϭ 0.015), 17OHP (r ϭ 1; P ϭ 0.01) and A (r ϭ 0.89; P ϭ 0.007) concentrations in peripheral blood. Conclusion:Testicular adrenal rest tumors produce adrenal-specific steroids and express adrenal-specific enzymes and ACTH and AII receptors, confirming the strong resemblance with adrenal tissue. Because AII receptors are present in tumor tissue, it can be hypothesized that AII may be an additional factor responsible for testicular adrenal rest tumor growth.

BACKGROUND:Free thyroxine (FT4) and free triiodothyronine (FT3) measurements are useful in the diagnosis and treatment of a variety of thyroid disorders. The IFCC Scientific Division established a Working Group to resolve issues of method performance to meet clinical requirements.