Biomedical subjects

O P Soldin

Publications and source records attributed to O P Soldin.

3 recordsLinked to original sources

PubMed2004

Trimester-specific reference intervals for thyroxine and triiodothyronine in pregnancy in iodine-sufficient women using isotope dilution tandem mass spectrometry and immunoassays.

BACKGROUND: Accurate assessment of the pregnant woman's thyroid status is critical, for both the initiation of thyroid hormone therapy and for the adjustment of thyroid hormone dose in those already receiving thyroid hormone. Trimester-specific intervals are especially important during pregnancy when thyroid insufficiency may be associated with adverse obstetric outcome and fetal neurodevelopmental deficits. We defined pregnancy-specific reference intervals for thyroxine (T4) and 3,5,3'-triiodothyronine (T3). We used a novel isotope dilution tandem mass spectrometry (LC/MS/MS) method, and compare these to reference intervals obtained by immunoassays (IAs) performed on the same samples. METHODS: Concentrations of circulating T4 and T3 were measured simultaneously during first, second and third trimesters and postpartum in iodine-sufficient, healthy, singleton pregnancies using API-3000 LC/MS/MS with deuterium-labeled internal standard (L-thyroxine-d2). Immunoassays were conducted on the same samples (T4 Dade Behring RxL, T3 DPC-Immunolite). RESULTS: Linear regression is reported for method comparisons; for T4, the slope decreased from r=0.900 in nonpregnant women to 0.802-0.820 during pregnancy. For T3, correlations between LC/MS/MS and immunoassays were weaker in all cases (r=0.407-0.574). CONCLUSION: In this longitudinal study, we established trimester-specific reference intervals for T4 and T3 by LC/MS/MS and compare these to intervals obtained by immunoassays.

Adult↗

PubMed2004

Trimester-specific changes in maternal thyroid hormone, thyrotropin, and thyroglobulin concentrations during gestation: trends and associations across trimesters in iodine sufficiency.

OBJECTIVES: To describe the interrelationships of thyroid functions based on trimester-specific concentrations in healthy, iodine-sufficient pregnant women across trimesters, and postpartum. METHODS: Circulating total 3,5,3'- triidothyronine (T(3)) and thyroxine (T(4)) concentrations were determined simultaneously using liquid chromatography tandem mass-spectrometry (LC/MS/MS). Free thyroxine (FT(4)), thyroid-stimulating hormone (TSH), and thyroglobulin (Tg) were measured using immunoassay techniques. Linear mixed effects models and correlations were calculated to determine trends and associations, respectively, in concentrations. RESULTS AND CONCLUSIONS: Trimester-specific T(3), FT(4), TSH, and Tg concentrations were significantly different between the first and third trimesters (all p < 0.05); second and third trimester values were not significantly different for FT(4), TSH, and Tg (all p > 0.25) although T3 was significantly higher in the third, relative to the second trimester. T(4) was not significantly different at any trimester (all p > 0.80). With two exceptions, analyte concentrations tended not to be correlated at each trimester and at 1-year postpartum. One exception was that T(3) and T(4) tended to be associated (all p < 0.05) at all time points except the third trimester (rho = 0.239, p > 0.05). T(4) and FT(4) concentrations tended to correlate positively during pregnancy (rho 0.361-0.382, all p < 0.05) but not postpartum (rho = 0.179, p > 0.05). Trends suggest that trimester-specific measurements of T(3), FT(4), Tg, and possibly TSH are warranted.

Adult↗

PubMed2001

Perchlorate clinical pharmacology and human health: a review.

Potassium perchlorate has been used at various times during the last 50 years to treat hyperthyroidism. Since World War II ammonium perchlorate has been used as a propellant for rockets. In 1997, the assay sensitivity for perchlorate in water was improved from 0.4 mg/L (ppm) to 4 microg/L (ppb). As a result, public water supplies in Southern California were found to contain perchlorate ions in the range of 5 to 8 ppb, and those in Southern Nevada were found to contain 5 to 24 ppb. Research programs have been developed to assess the safety or risk from these exposures and to assist state and regulatory agencies in setting a reasonable safe level for perchlorate in drinking water. This report reviews the evidence on the human health effects of perchlorate exposure. Perchlorate is a competitive inhibitor of iodine uptake. All of its pharmacologic effects at current therapeutic levels or lower are associated with inhibition of the sodium-iodide symporter (NIS) on the thyroid follicular cell membrane. A review of the medical and occupational studies has been undertaken to identify perchlorate exposure levels at which thyroid hormone levels may be reduced or thyrotropin levels increased. This exposure level may begin in the 35 to 100 mg/d range. Volunteer studies have been designed to determine the exposure levels at which perchlorate begins to affect iodine uptake in humans. Such effects may begin at levels of approximately 1 mg/d. Environmental studies have assessed the thyroidal health of newborns and adults at current environmental exposures to perchlorate and have concluded that the present levels appear to be safe. Whereas additional studies are underway both in laboratory animals and in the field, it appears that a safe level can be established for perchlorate in water and that regulatory agencies and others are now trying to determine that level.

Carrier Proteins↗