The effect of control of diabetes mellitus on plasma T4, T3, rT3 levels and half muscle relaxation period

International Nuclear Information System (INIS)

Ismail, A.A.; Hafiez, A.A.; Sayed, S.N.; Abbas, E.Z.; Halawa, F.A.; Youssef, M.M.

1984-01-01

25 diabetics of the maturity onset type who showed no clinical evidence of either peripheral neruropathy or diabetic amyotrophy were selected for this study. All patients were subjected to the following investigations: estimation of half muscle relaxation period of the quadriceps muscle knee-jerk, measurement of plasma levels of thyroxine (T 4 ), triiodothyronine (T 3 ) and reverse triiodothronine (rT 3 ), determination of fasting and two hours postprandial blood sugar levels. The quadriceps muscle relaxation period in uncontrolled diabetics was significantly longer than in normals. Control of diabetes by glibenclamide or gliclazide did not cause a significant change in muscle relaxation period. There was also no significant difference between the effects of the two drugs. (author)

Effect of adjuvant lithium on thyroxine (T4) concentration after radioactive iodine therapy

Energy Technology Data Exchange (ETDEWEB)

Hammond, Emmanuel NiiBoye; Vangu, Mboyo-Di-Tamba Heben Willy [University of the Witwatersrand, Division of Nuclear Medicine and Molecular Imaging, Department of Radiation Sciences, Johannesburg (South Africa)

2016-10-15

To study the effect of adjuvant lithium on serum thyroxine (T4) concentrations in patients treated with radioactive iodine (RAI) therapy in our environment. This was a prospective simple randomized comparative, experimental cohort study of patients with hyperthyroidism referred for RAI ablation therapy in the two main academic hospitals in Johannesburg between February 2014 and September 2015. Amongst the 163 participants in the final analysis, 75 received RAI alone and 88 received RAI with lithium. The difference in mean T4 concentrations at 3 months between the RAI-only group (17.67 pmol/l) and the RAI with lithium group (11.55 pmol/l) was significant with a small effect size (U = 2328.5, Z = -2.700, p = 0.007, r = 0.01). Significant decreases in T4 concentrations were observed as early as 1 month after RAI (p = 0.0001) in the RAI with lithium group, but in the RAI-only group, significant decreases in T4 concentrations were observed only at 3 months after RAI therapy (p = 0.000). Women and patients with Graves' disease who received RAI with adjuvant lithium also showed significant decreases in T4 concentrations at 1 month (p = 0.002 and p = 0.003, respectively). Adjuvant lithium leads to an earlier and better response to RAI therapy with lower T4 concentrations that are achieved earlier. This earlier response and decrease in T4 concentrations were noted in patients with Graves' disease and nodular goitre, and in women with hyperthyroidism who received adjuvant lithium therapy. (orig.)

Serum levels of triiodothyronine (T3) and thyroxine (T4) in buffalo (Bubalus bubalis Lin.) raised in Amazon region

International Nuclear Information System (INIS)

Silva, A.O.A. da.

1991-08-01

Through the use of radioimmunoassay (RIA) it was determined blood serum concentration of triiodothyronine (T 3 ) and thyroxine (T 4 ) (n=78) for two different water buffalo racial groups. Blood serum was collected from young and adult animals belonging to two farms in Castanhal country, state of Para, Brazil, through the year of 1988. The serum levels of T 3 and T 4 were statistically correlated with climatic parameters, e.g., pluviometric precipitation, environmental temperature, humidity, light intensity variation and physiological factors such as age, breed and sex. It was identified two seasons during experiment, one season the rainfall period with high precipitation rates and the other one was considered as dry season, with low precipitation rates. The average rate of temperature and humidity have shown no significant statistic difference between the two seasons. On the other hand, it was found a significant relationship between luminosity and seasons, since when the luminosity decreases the pluviometric rates increases. (author). 51 refs, 15 figs, 15 tabs

Method for the determination of a new indicator proportional to the plasma concentration of free thyroxine

International Nuclear Information System (INIS)

Deutsch, G.

1979-11-01

A novel method for the estimation of free thyroxine (T 4 ) in serum is described. Partially heat-denatured serum is mixed with 125 I-labelled T 4 bound to thyroxine-binding globulin (TBG) on a Sephadex column. After a period of equilibration, the column is eluted with buffer and the residual radioactivity on the column measured. This represents the fraction of 125 I-labelled T 4 freed from TBG and can be related to the concentration of free T 4 in the serum, being expressed as ''proportional free thyroxine'' (PFT 4 ) in μg per 100 ml. In studies of the method, a coefficient of variation of 4.52% in the results was found. The mean PFT 4 value in 124 normal subjects was 7.26 +- 1.25 μg per 100 ml. Values below 4.8 μg per 100 ml were considered indicative of hypothyroidism and those above 9.8 μg per 100 ml indicative of hyperthyroidism, in good agreement with clinical findings. The coefficient of correlation between the results and results obtained by the AMES ''Tetralute'' method was 0.911. The mean PFT 4 value in 37 pregnant subjects was 12.2 +- 2.1 μg per 100 ml

Combined radioimmunoassay for triiodothyronine and thyroxine

International Nuclear Information System (INIS)

Denning, C.E.; Schick, L.A.

1980-01-01

A method for the combined radioimmunoassay for the hormones triiodothyronine (T-3) and thyroxine (T-4) in serum or plasma, wherein the radiolabeled t-3 and t-4 reagents are t-3 and t-4 labeled with the same radioisotope. The hormones are extracted from the serum or plasma sample and separated from their binding proteins by adsorption to a crosslinked dextran gel at a highly alkaline ph. After washing away the dissociated proteins, a predetermined limiting amount of t-3 antibody is incubated with the gel and thereafter radiolabeled t-3 which has become extracted from the gel by antibody binding is washed away. Excess t-3 antibody and a predetermined limiting amount of t-4 antibody are then incubated with the gel and radiolabeled t-3 and t-4 which has become extracted from the gel by antibody binding are thereafter washed away. The respective relative amounts of radiolabeled t-3 and t-4 retained by the gel after the incubations with the respective limiting amounts of t-3 and t-4 antibody are compared with standard results to quantitate the hormones in the sample. The use of excess t-3 antibody in the t-4 antibody incubation is critical to the accuracy of the method, enabling the use of the same radioisotope for radiolabeling t-3 and t-4

Free thyroxin by radioimmunoassay: evaluation of a new direct method involving a radiolabeled thyroxin analog

International Nuclear Information System (INIS)

Kubasik, N.P.; Lundberg, P.A.; Brodows, R.G.; Hallauer, G.D.; Same, D.G.; Lindstedt, G.; Bengtsson, C.; Nystroem, E.

1983-01-01

The first performance evaluation of a new direct method for free thyroxin (T4) in serum by radioimmunoassay, with use of coated tubes and a radioiodinated T4 analog (Diagnostic Products Corp.) is presented. The assay is precise and robust: within-run imprecision (CV), 3.1-6.6%; between-run imprecision, 4.0-7.9%; no demonstrable variation between technologists irrespective of experience with the method. No outliers were observed when we compared the free T4 results with serum total T4. Reference values are reported for a total of 1243 euthyroid subjects; there was no significant age effect on serum free T4 in women 26 to 72 years old. The biological variation was about +/- 35% of the mean (2 SD). Free T4 results are the same for serum and plasma. The assay performs well in hypothyroidism and hyperthyroidism, and distinguishes individuals with thyroid disease from normal individuals. Free T4 values in women taking oral contraceptives are normal. Depressed results were often observed in acute nonthyroidal illness and continuing pregnancy. These results were directly comparable with those of another commercial direct radiolabeled-T4 analog kit for free T4

Evaluation of a new free-thyroxin assay

International Nuclear Information System (INIS)

Welby, M.L.; Guthrie, L.; Reilly, C.P.

1981-01-01

The Amerlex Free Thyroxin (T 4 ) Radioimmunoassay Kit (Amersham International Ltd.) is a new direct equilibrium radioimmunoassay for free T 4 based on an antiserum with very high affinity for T 4 , and a unique 125 l-labeled T 4 analog as tracer. It is a very simple single-tube radioimmunoassay, making use of Amerlex particles to separate antibody-bound from free species. Interassay precision (CV) is 3.7% at 13 pmol/L and 2.3% at 30 pmol/L; within-assay precision is 4.2% at 21 pmol/L. The reference interval is 11-22 pmol/L. The assay did not misclassify any patients tested who had untreated myxedema or untreated thyrotoxicosis. The free T 4 assay excelled both the free T 4 index and the T 4 /T 4 -binding globulin ratio in correcting for increased thyroxin-binding globulin from pregnancy, and it was better than the index but not better than the ratio in correcting for increased thyroxin-binding globulin in users of oral contraceptives

Thyroxine (T4) radioimmunoassay using filter paper dried blood sample: an attempt for screening of neonates for hypothyroidism

International Nuclear Information System (INIS)

Afroz, S.; Hussain, R.; Ahmed, K.

1997-01-01

This paper describes a sensitive but simple and less expensive method suitable for estimation of thyroxine (T 4 ) level. Deficiency of iodine during fetal life results in neonatal hypothyroidism and critinism. Frequency of neonatal hypothyroidism is 1 in 5000 to 7000 in countries having iodine deficiency. It is therefore important to diagnose the neonatal hypothyroidism as soon as possible after birth. The estimation of thyroxine has been found to the a reliable index for diagnosis of hypothyroidism and has long been used for screening of neonatal hypothyroidism. In the present study, instead of serum sample, a 6 mm disc of filter paper containing dried blood sample was used. The test was carried out in the laboratory with 40 samples. As compared to the sensitivity of serum sample technique which is 15.19 n mol/L, the filter paper technique has the sensitivity of 17.23 n mol/L. The work revealed that the T 4 concentration do not depend upon the amount of blood on the filter paper. Effect of temperature on filter paper disc was evaluated at 4 o c, at 25 o c and at 37 o c. Results obtained showed significant variation and the best result was obtained for the sample kept at 4 o c. The method is simple, rapid, less expensive and needs a small amount of blood and is, therefore, a useful technique for mass screening of neonatal hypothyroidism. 6 refs., 4 tables (author)

Treating Hypothyroidism with Thyroxine/Triiodothyronine Combination Therapy in Denmark

DEFF Research Database (Denmark)

Michaelsson, Luba Freja; Medici, Bjarke Borregaard; la Cour, Jeppe Lerche

2015-01-01

BACKGROUND: Five to ten percent of patients with hypothyroidism describe persistent symptoms despite being biochemically well regulated on levothyroxine (L-T4). Thyroxine (T4)/triiodothyronine (T3) combination therapy [L-T4/liothyronine (L-T3) or desiccated thyroid] are still regarded as experime......BACKGROUND: Five to ten percent of patients with hypothyroidism describe persistent symptoms despite being biochemically well regulated on levothyroxine (L-T4). Thyroxine (T4)/triiodothyronine (T3) combination therapy [L-T4/liothyronine (L-T3) or desiccated thyroid] are still regarded...

In vitro fluorescence displacement investigation of thyroxine transport disruption by bisphenol A

Institute of Scientific and Technical Information of China (English)

Jie Cao; Liang-Hong Guo; Bin Wan; Yin Wei

2011-01-01

Bisphenol A (BPA) is a chemical with high production volume and wide applications in many industries.Although BPA is known as an endocrine disruptor, its toxic mechanisms have not been fully characterized.Due to its structural similarity to thyroid hormones thyroxine (T4) and triiodothyronine (T3), one possible mechanism of BPA toxicity is disruption of hormone transport by competitive binding with the transport proteins.In this study, the binding interactions of BPA, T4, and T3 with three thyroid hormone transport proteins, human serum albumin (HSA), transthyretin (TTR), and thyroxine-binding globulin (TBG) were investigated by fluorescence measurement.Using two site-specific fluorescence probes dansylamide and dansyl-L-proline, the binding constants of BPA with HSA at drug site I and site Ⅱ were determined as 2.90 × 104 and 3.14 × 104 L/mol, respectively.By monitoring the intrinsic fluorescence of tryptophan, a binding constant of 4.70 × 103 L/mol was obtained.Similarly, by employing 8-anilino-1-naphthalenesulfonic acid as fluorescence probe, the binding affinity of BPA with TTR and TBG was measured to be 3.10 × 105 and 5.90 × 105 L/mol, respectively.In general, BPA showed lower binding affinity with the proteins than T3 did, and even lower affinity than T4.Using these binding constants, the amount of BPA which would bind to the transport proteins in human plasma was estimated.These results suggest that the concentrations of BPA commonly found in human plasma are probably not high enough to interfere with T4 transport.

Basal levels of triiodotironine, thyroxine, thyrotropin, free thyroxine and reverse triiodotyronine in patients with chronic renal failure submitted to hemodialysis

International Nuclear Information System (INIS)

Knobel, H.; Mendonca, B.B. de; Mendes, V.; Rocha Junior, J.E.; Medeiros Neto, G.

1987-01-01

Serum triiodotironine (T3), thyroxine (T4), thyrotropin (TSH), free thyroxine (FT4) and reverse triiodothyronine (rT3) concentrations were determined by radioimmunoassay in 21 uremic patients on regular hemodialysis therapy (sera were collected immediately before dialysis) and 11 normal controls. In advanced chronic renal failure serum T3 and T4 were frequently decreased (86% and 57%, respectively). and serum rT3 was normal (81%) or subnormal (14%). The serum TSH and FT4 values were normal in all cases even when serum T3 and T4 concentrations were decreased below the normal range. The findings suggest that the measurement of serum TSH probably represents the most reliable differentiation between this disease with low T4 levels and primary hypothyroidism. (author)

The effect of phenobarbital on the metabolism and excretion of thyroxine in rats

International Nuclear Information System (INIS)

McClain, R.M.; Levin, A.A.; Posch, R.; Downing, J.C.

1989-01-01

The effect of phenobarbital on thyroid function and the metabolism and biliary excretion of thyroxine in rats was determined. Phenobarbital, administered for 2 weeks at a dose of 100 mg/kg/day, resulted in an increase in hepatic and thyroid gland weights, decreased circulating levels of T4, T3 and rT3, and increased TSH levels in male and female rats. After 3 months of treatment liver and thyroid weights were still increased; however, hormone values were not as markedly affected indicating that the rats had partially compensated for the effect on thyroid function. In thyroidectomized rats the plasma clearance of thyroxine was increased with phenobarbital. In bile duct cannulated phenobarbital-treated male rats the hepatic uptake at 4 hr was markedly increased. Bile flow was increased and the 4-hr cumulative biliary excretion of administered radioactivity was increased by 42%. Most of the increase in the excretion (76%) was accounted for by an increase in the excretion of thyroxine-glucuronide in phenobarbital-treated rats. Hepatic thyroxine-glucuronyltransferase activity in phenobarbital-treated rats expressed as picomoles per milligram of protein was increased by 40%; enzyme activity per gram of liver was increased by about twofold which, coupled with increased hepatic weight, resulted in about a threefold increase in total hepatic thyroxine-glucuronyltransferase activity in phenobarbital-treated rats as compared to that of controls. Qualitatively similar effects on metabolism, excretion, and enzyme induction were noted in female rats; however, the magnitude of increase was less than that observed in male rats. It is concluded that the effect of phenobarbital on thyroid function in rats is primarily a result of its effects on the hepatic disposition of thyroid hormone

The colloidal thyroxine (T4) ring as a novel biomarker of perchlorate exposure in the African clawed frog Xenopus laevis

Science.gov (United States)

Hu, F.; Sharma, Bibek; Mukhi, S.; Patino, R.; Carr, J.A.

2006-01-01

The purpose of this study was to determine if changes in colloidal thyroxine (T4) immunoreactivity can be used as a biomarker of perchlorate exposure in amphibian thyroid tissue. Larval African clawed frogs (Xenopus laevis) were exposed to 0, 1, 8, 93, and 1131 ??g perchlorate/l for 38 and 69 days to cover the normal period of larval development and metamorphosis. The results of this study confirmed the presence of an immunoreactive colloidal T4 ring in thyroid follicles of X. laevis and demonstrated that the intensity of this ring is reduced in a concentration-dependent manner by perchlorate exposure. The smallest effective concentration of perchlorate capable of significantly reducing colloidal T4 ring intensity was 8 ??g perchlorate/l. The intensity of the immunoreactive colloidal T4 ring is a more sensitive biomarker of perchlorate exposure than changes in hind limb length, forelimb emergence, tail resorption, thyrocyte hypertrophy, or colloid depletion. We conclude that the colloidal T4 ring can be used as a sensitive biomarker of perchlorate-induced thyroid disruption in amphibians. ?? Copyright 2006 Oxford University Press.

Serum levels at moment of breeding of triiodothyronine (T3), thyroxine (T4), and progesterone in Saanen goats females during normal and induced heat and testosterone in 12 Saanen goats males

International Nuclear Information System (INIS)

Prestes, Nereu C.; Vulcano, Luiz C.; Mamprim, Maria J.; Oba, Eunice

1996-01-01

The aim of this experiment was to measure the level of triiodothyronine(T 3 ), thyroxine(T 4 ) and progesterone in the serum of females Saanen goats. The progesterone levels were: 0.59 and 0.79 ng/μl considering breeding during normal and induced heat respectively. The T 3 values were: 192.8 and 251.32 ng/dl while T 4 values were: 36.38 and 31.68 ng/dl in the same condition above. The average testosterone level at the moment of breeding in the serum of 12 males was 1.38 pg/ml. (author)

Effects of Hypothyroidism and Exogenous Thyroxine on ...

African Journals Online (AJOL)

Summary: Thyroxine (T4) is important in gut development and maturation, and its use in treating hypothyroidism is becoming more popular. This study was conducted to evaluate the effect of thyroidectomy and thyroxine replacement on some gastrointestinal organs. Ten out of 20 thyroidectomised rats received 100pg/kgbw ...

Comparison of serum levels of Tri‐iodothyronine (T3, Thyroxine (T4, and Thyroid‐Stimulating Hormone (TSH in preeclampsia and normal pregnancy

Directory of Open Access Journals (Sweden)

Nayereh Khadem

2012-01-01

Full Text Available Background: The physiological changes in thyroid gland during pregnancy have been suggested as one of the pathophysiologic causes of preeclampsia.Objective: The aim of this study was comparison of serum levels of Tri‐iodothyronine (T3, Thyroxine (T4, and Thyroid‐Stimulating Hormone (TSH in preeclampsia and normal pregnancy. Materials and Methods: In this case‐control study, 40 normal pregnant women and 40 cases of preeclampsia in third trimester of pregnancy were evaluated. They were compared for serum levels of Free T3 (FT3, Free T4 (FT4 and TSH. The data was analyzed by SPSS software with the use of t‐student, Chi‐square, Independent sample T-test and Bivariate correlation test. p≤0.05 was considered statistically significant. Results: The mean age was not statistically different between two groups (p=0.297. No significant difference was observed in terms of parity between two groups (p=0.206. Normal pregnant women were not significantly different from preeclampsia cases in the view of FT3 level (1.38 pg/ml vs. 1.41 pg/ml, p=0.803, FT4 level (0.95 pg/ml vs. 0.96 pg/ml, p=0.834 and TSH level (3.51 μIU/ml vs. 3.10 μIU/ml, p=0.386. Conclusion: The findings of the present study do not support the hypothesis that changes in FT3, FT4 and TSH levels could be possible etiology of preeclampsia

Plasma corticosterone and thyroxine concentrations during chronic ingestion of crude oil in mallard ducks (Anas platyrhynchos)

Science.gov (United States)

Rattner, B.A.; Eastin, W.C.

1981-01-01

1. Blood samples were collected from mallard ducks after 6, 12, and 18 weeks of dietary exposure to mash containing 0.015%, 0.150%, and 1.500% crude oil.2. Plasma corticosterone concentrations in ducks fed mash containing 0.150% or 1.500% Alaskan Prudhoe Bay crude oil were uniformly depressed when compared to values in untreated control birds.3. Plasma thyroxine concentration was not altered in ducks chronically exposed to crude oil.4. The observed alteration in corticosterone concentration could reduce tolerance to temperature and dietary fluctuations in the environment.

Effects of thyroxine (T4) and triiodothyronine (T3) on the thyrotropin (TSH) response to TSH-releasing hormone (TRH) in the rat

International Nuclear Information System (INIS)

Boado, R.J.; Ulloa, E.R.; Zaninovich, A.A.

1982-01-01

Wistar rats were treated with 7.8 or 260 nmols T4/100 g BW, 1.5 or 260 nmols T3/100 g BW, or saline as control. Twenty minutes later 1 μg TRH/100 g BW was injected iv. Heparinized blood samples were drawn at times 0 and 30 minutes (10 min post-TRH) for determination of plasma TSH, T4 and T3 by RIA. Other group of rats were administered with 150 μCi of 3',5'- 125 I-T4 prepared by iodination of 3,5-diiodothyronine. Thirty minutes later the hypophyses were removed, and chromatographed. Other group of animals were treated with 5 mg of iopanoic acid (IOP)/100 g BW. Thereafter, rats were injected iv with 260 nmols T4 or T3/100 g BW and the TRH-test performed as described above. In the control group there was a 11-fold increase in plasma TSH at 10 minutes post-TRH. In rats treated with 260 nmols T4 the post-TRH increment in plasma TSH was 5+-1-fold (p 125 I-T3 in the hypophyses 30 minutes after 125 I-T4 administration. The present data indicate that T4 is capable of depressing the release of TSH in response to TRH stimulation in normal rats. (M.E.L.) [es

Comparative characterization of thyroid hormone receptors and binding proteins in rat liver nucleus, plasma membrane, and cytosol by photoaffinity labeling with L-thyroxine

International Nuclear Information System (INIS)

Dozin, B.; Cahnmann, H.J.; Nikodem, V.M.

1985-01-01

Photoaffinity labeling with underivatized thyroxine (T4) was used to identify and compare the T4 binding proteins in rat liver cytosol, nuclear extract, and purified plasma membrane. When these subcellular fractions were incubated with a tracer concentration of [125I]T4, irradiated with light above 300 nm, and individually analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the radioactivity profiles revealed the presence of T4 binding proteins of molecular masses of 70, 52, 43, 37, 30, and 26 kilodaltons (kDa) in cytosol, of 96, 56, 45, and 35 kDa in nuclear extract, and of 70, 44, and 30 kDa in plasma membrane. Competition experiments performed in the presence of a 1000-fold excess of unlabeled T4 demonstrated that these binding proteins display different hormone binding activities. The similar electrophoretic mobilities of some binding proteins present in the different subcellular fractions, i.e., the 70-, 43-45-, and 30-kDa proteins, suggested that these proteins might be identical. However, double-labeling experiments in which plasma membrane, nuclear extract, and cytosol were photolabeled with either [125I] or [131I]T4 and mixed, two at a time, in all possible combinations showed that from one cellular fraction to another, the radioactivity peaks corresponding to the approximately 70-, 43-45-, and 30-kDa proteins were not superimposed. Their relative positions on the gel differed by one or two slices, which indicated differences in molecular mass of 1.9-3.6 kDa. Moreover, enzymatic digestion with Staphylococcus aureus V8 protease of these three proteins, prepared from each subcellular fraction, yielded dissimilar peptide patterns

Free serum thyroxine

International Nuclear Information System (INIS)

Degrossi, O.J.; Altschuler, Noe; Cabrejas, M.L. de; Pinkas, Mirta; Garcia del Rio, Hernan

1982-01-01

The use of radiommunoassay (RIA) tehcniques has increased the diagnosis of thyroid functional alterations. A solid phase RIA method for free thyroxine (FT4) measurement was tested. Serum FT4, Total T4, T3 and TSH were determined by radioimmunoassay in 179 subjects. One hundred twenty two patients were normal (8 to 75 years old); FT4 was 1.42 +- 0.03 ng/100 ml (avg. value and std. error). In 27 cases of thyrotoxicosis the values were 4.66 +- 0.48 ng/100 ml and in 15 cases of hypothyroidism 0.50 +- 0.06 ng/100 ml (statistics probability [es

Effect of Propranolol on Thyroxine-Induced Changes in Body Temperature and Metabolism During Exercise in Dogs

Science.gov (United States)

Kaciuba-Uscilko, Hanna; Brzezinska, Zofia; Greenleaf, John E.

1976-01-01

Effects of thyroxine on temperature and metabolism during exercise were studied in dogs after beta-adrenergic blockade. Dogs performed 60 min treadmill exercise of moderate intensity 5 and 72 h following thyroxine injected s. c. in a single dose of 0.1 mg/kg b.w. Thyroxine increased significantly the lipolytic response to exercise as well as blood lactate (LA) concentrations and rectal temperature (T(sub re)) during exercise as early as 5 h following the hormone administration. The changes became more pronounced 72 h after the injection. At rest T(sub re), blood FFA (free fatty acid) and LA levels in the thyroxine-treated dogs did not differ from the control values, and blood glucose was slightly, but significantly higher. Propranolol given intravenously in a dose of 0.25 mg/kg at 30 min of the exercise performed 72 h following thyroxine injection abolished the plasma FFA rise, and inhibited to a certain extent increases in T(sub re) and blood LA concentrations during the next 30 min of exercise.

Conception of dairy cows in different seasons of the year in relation to thyroxine (T4) and triiodothyronine (T3) concentrations

International Nuclear Information System (INIS)

Bekeova, E.; Elecko, J.; Hendrichovsky, V.; Hajurka, V.; Choma, J.; Krajnicakova, M.

1989-01-01

The investigation took place in March, June and November following estrus synchronization with cloprostenol. The concentrations of thyroxine and triiodothyronine in the blood serum were determined by RIA using commercial kits. It is derived from the results that conception of dairy cows is in indirect proportion to the thyroid hormone levels. (M.D.). 4 figs., 4 tabs., 22 refs

Thyroid hormones in the elderly sick: "T4 euthyroidism".

Science.gov (United States)

Burrows, A W; Shakespear, R A; Hesch, R D; Cooper, E; Aickin, C M; Burke, C W

1975-11-22

Thyroid function and serum levels of triiodothyronine (T3) and thyroxine (T4) were investigated in 79 euthyroid geriatric patients. Of the 59 inpatients and 20 outpatients 35 (59%) and 2, respectively, had low T3 levels. In contrast, 7 (12%) and 6 (30%), respectively, had raised T4 levels. Two further patients were excluded from the study because of raised levels of thyroid-stimulating hormone. Thyroxine-binding globulin was greatly increased in both groups of patients, but low serum albumin levels were present in 31 (39%). Despite these changes free T3 and T4 indices closely followed total T3 and T4 levels. The difference between the two groups of patients did not correlate with body weight, diagnostic categories, age, drug treatment, or duration of stay in hospital.

A genome-wide association study of thyroid stimulating hormone and free thyroxine in Danish children and adolescents

DEFF Research Database (Denmark)

Nielsen, Tenna Ruest Haarmark; Appel, Emil Vincent Rosenbaum; Svendstrup, Mathilde

2017-01-01

BackgroundHypothyroidism is associated with obesity, and thyroid hormones are involved in the regulation of body composition, including fat mass. Genome-wide association studies (GWAS) in adults have identified 19 and 6 loci associated with plasma concentrations of thyroid stimulating hormone (TSH......) and free thyroxine (fT4), respectively.ObjectiveThis study aimed to identify and characterize genetic variants associated with circulating TSH and fT4 in Danish children and adolescents and to examine whether these variants associate with obesity.MethodsGenome-wide association analyses of imputed genotype...... data with fasting plasma concentrations of TSH and fT4 from a population-based sample of Danish children, adolescents, and young adults, and a group of children, adolescents, and young adults with overweight and obesity were performed (N = 1,764, mean age = 12.0 years [range 2.5-24.7]). Replication...

Serum levels of triiodothyronine (T{sub 3}) and thyroxine (T{sub 4}) in buffalo (Bubalus bubalis Lin.) raised in Amazon region; Niveis sericos de triiodotironina (T{sub 3}) e tiroxina (T{sub 4}) em bubalinos (Bubalus bubalis Lin.) criados na regiao Amazonica

Energy Technology Data Exchange (ETDEWEB)

Silva, A O.A. da

1991-08-01

Through the use of radioimmunoassay (RIA) it was determined blood serum concentration of triiodothyronine (T{sub 3}) and thyroxine (T{sub 4}) (n=78) for two different water buffalo racial groups. Blood serum was collected from young and adult animals belonging to two farms in Castanhal country, state of Para, Brazil, through the year of 1988. The serum levels of T{sub 3} and T{sub 4} were statistically correlated with climatic parameters, e.g., pluviometric precipitation, environmental temperature, humidity, light intensity variation and physiological factors such as age, breed and sex. It was identified two seasons during experiment, one season the rainfall period with high precipitation rates and the other one was considered as dry season, with low precipitation rates. The average rate of temperature and humidity have shown no significant statistic difference between the two seasons. On the other hand, it was found a significant relationship between luminosity and seasons, since when the luminosity decreases the pluviometric rates increases. (author). 51 refs, 15 figs, 15 tabs.

In vitro thyroid testing in populations with low thyroxine binding globulin capacity

Energy Technology Data Exchange (ETDEWEB)

Cuaron, A

1993-12-31

Total thyroxine (T{sub 4}) concentration in serum is a reliable indicator of thyroid function in most individuals, but it is affected by altered concentrations of thyroxine-binding globulin (TBG) in serum. Within certain limits, the variations in total TBG binding capacity (TBG{sub TOTAL}) caused by the fluctuations in the concentration of this binding globulin in serum can be modulated by calculating the free thyroxine index (FT{sub 4}I) as the product of T{sub 4} and the in vitro uptake of triiodothyronine by a secondary binder (T{sub 3}U). This calculation is empirically based on the facts that free TBG binding capacity (TBG{sub FREE}) is inversely related to T{sub 3}U and that T{sub 4} and T{sub 3}U show opposite behaviour when measured in sera with altered TBG: a low T{sub 4} in serum with reduced TBG{sub TOTAL} is compensated by a high value for T{sub 3}U, while an elevated T{sub 4} in serum with increased TBG{sub TOTAL} is compensated by a low value for T{sub 3}U. In both cases the product of T{sub 4} and T{sub 3} renders a normal FT{sub 4}I value, showing a certain association with the concentration of free T{sub 4} in serum (FT{sub 4}). In fact, this index has been shown to be superior than several FT{sub 4} assay systems in the assessment of thyroid status in clinical euthyroid subjects with relatively high or low T{sub 3}U 3 figs, 4 tabs

Thyroxine and thyrotropin radioimmunoassays using dried blood samples on filter paper for screening of neonatal hypothyroidism

International Nuclear Information System (INIS)

Beckers, C.; Cornette, C.; Francois, B.; Bouckaert, A.; Lechat, M.

1977-01-01

A routine and automatized methodology for thyroxine (T4) and thyrotropin (TSH) radioimmunoassay (RIA) using dried blood samples on filter paper is described. Five mm diameter dots were prepared. One eluted dot, corresponding to 4 μl of plasma, was used for T4-RIA while two were necessary for TSH-RIA. Reference filter papers were introduced in each assay for quality control. In a preliminary study on 1903 newborns, samples were obtained, generally between the 5th-7th day. Mean dot T4 was 7.38 +- 2.5 μg/dl. Mean dot TSH was 11.83 +- 9.1 μU/ml, the equation of the regression line between dot TSH (y) and serum TSH (x) being Y = 10.29 + 0.623x. (orig.) [de

Serum free-thyroxine modifications with age and in normal pregnancy

International Nuclear Information System (INIS)

Degrossi, O.J.; Altschuler, N.; Watanabe, T.; Pinkas, M.; Damilano, S.; Garcia del Rio, H.

1982-01-01

The possibility of using radioimmunoassay techniques (RIA) in the assessment of circulating thyroid hormones, total thyroxine (T4) and triiodothyronine (T3) has particularly increases the diagnosis of thyroid diseases. Thyroidal hormones circulate bound to proteins; therefore, variations in the transport capacity of the latter will produce important modifications in the T4 and T3 figures. Only small fractions, less than 0.05% for T4 and than 0.5% for T3, circulate in the free form and are considered as metabolically active forms of both hormones. In order to attain a correct clinical valuation, the rates of the free fractions as well as the total rates of these hormones must be known. Recently, these studies of free hormones are carried out by means of RIA, with the consequent advantages. The variations in serum free thyroxine (FT4) under certain physiogical conditions, such as for different ages and during pregnancy, were particularly studied

2012 ETA Guidelines: The Use of L-T4 + L-T3 in the Treatment of Hypothyroidism

DEFF Research Database (Denmark)

Nygaard, Birte

2012-01-01

. Results: Suggested explanations for persisting symptoms include: awareness of a chronic disease, presence of associated autoimmune diseases, thyroid autoimmunity per se, and inadequacy of L-T4 treatment to restore physiological thyroxine (T4) and triiodothyronine (T3) concentrations in serum and tissues...

A Clinical Study on 125IT3 Resin Uptake Rate and Serum Thyroxin(T4) in Hyperthyroidism

International Nuclear Information System (INIS)

MooN, Ern Soo; Park, Yoh Han; Cho, Chang Ho; Park, In Soo; Lee, Chong Suk; Lee, Hak Choong

1978-01-01

Hyperthyroidism may be defined as those clinical conditions which result from an increase in the circulating levels of one or both thyroid hormones. Hyperthyroidism in broad sense could be classified with toxic diffuse goiter, toxic adenomatous goiter, and toxic multinodular goiter on the basis of the circulating thyroid hormone levels. For this study, the subject included 94 cases with hyperthyroidism were presented in 77 with toxic diffuse goiter, 8 with toxic adenomatous goiter, and 9 with toxic multinodular goiter on the levels of 125 IT 3 resin uptake rate and serum thyroxine (T 4 ). The observed results were as follows: 1) In the cases of hyperthyroidism including toxic diffuse goiter, toxic adenomatous goiter, and toxic multinodular goiter, 20.21% of the patients were male and 79.79% female. The majority of the patients were in 2nd to 4th decades of their lives. 2) There were objective signs clearly manifested in hyperthyroidism including toxic diffuse goiter and toxic adenomatous goiter which were rare in the multinodular goiter. The clinical signs in toxic diffuse and toxic adenomatous goiter included wide pulse pressure, tachycardia, systolic murmur, exophthalmos, tremor and warm skin etc. 3) The most frequent complaints of the patients with hyperthyroidism were palpitation, weight loss, increased appetite, perspiration, heat intolerance, nervousness, exertional dyspnea, and menstrual disturbance etc. There was no clear difference in the incidence of symptoms between toxic diffuse goiter and toxic adenomatous goiter, but there was clear difference between toxic multinodular goiter. 4) Considering of results of 125 IT 3 resin uptake rate and serum T 4 level in toxic diffuse goiter, toxic adenomatous goiter and toxic multinodular goiter, 125 IT 3 resin uptake rate was 49.15±9.94% (mean) and serum T 4 21.29±7.04 ug/dl (mean) in toxic diffuse goiter. In toxic multinodular goiter, 125 I T 3 resin uptake rate was 32.47±6.74% (mean) and serum T 4 level 11.03�

Measurement of serum free thyroxine using fT4(fraction) determined by solidphase radioimmunoassay: First clinical results

International Nuclear Information System (INIS)

Reiners, C.; Walter, H.; Moll, E.; Boerner, W.

1983-01-01

The novel solidphase RIA SPAC ET permits the simultaneous determination of TF 4 , TT 4 and fT 4 -fraction. The duration until the complete results of this assay can be obtained is a little bit less than for parallel radioimmunologic FT 4 - and TT 4 -determinations. The results of our quality control survey indicate that the precision of the precommercial kits tested should be improved. In addition, the normal range of FT 4 from 5.5 pg/ml to 12.5 pg/ml should be adapted in the final assay version of the approximately 30% higher normal ranges which are common with alternative FT 4 -radioimunoassays. In comparison to FT 4 -I, TT 4 /TBG-ratio and other FT 4 -radioimmunoassays, the diagnostic accuracy of FT 4 determined by SPAC ET is equally good. Estrogen-mediated TBG elevations on oral contraceptives are well compensated. In pregnancy, the known tendency towards lower FT 4 levels can be seen with the beginning of the second trimester. While there are no changes of FT 4 levels on medication with acetylosalicyclic acid, a slight tendency towards lower FT 4 determined by SPAC ET can be seen on therapy with phenytoin. Under treatment with heparin, FT 4 by SPAC ET is elevated. This is more reasonable than the decreases of FT 4 concentrations observed with radioimmunoassays using FT 4 analogues as tracers. RIA SPAC ET is an interesting alternative to routinely used direct and indirect methods for determination of free thyroxine. (orig.) [de

Biosensor discovery of thyroxine transport disrupting chemicals

NARCIS (Netherlands)

Marchesini, G.R.; Meimaridou, A.; Haasnoot, W.; Meulenberg, E.; Albertus, F.; Mizuguchi, M.; Takeuchi, M.; Irth, H.; Murk, A.J.

2008-01-01

Ubiquitous chemicals may interfere with the thyroid system that is essential in the development and physiology of vertebrates. We applied a surface plasmon resonance (SPR) biosensor-based screening method for the fast screening of chemicals with thyroxine (T4) transport disrupting activity. Two

Acute redistribution of thyroxine after the administration of univalent anions, salicylate, theophylline and barbiturates in rats

Energy Technology Data Exchange (ETDEWEB)

Langer, P; Kokesova, H; Gschwendtova, K [Slovenska Akademia Vied, Bratislava (Czechoslovakia). Ustav Experimentalni Endocrinologie

1976-01-01

Rats were injected with (/sup 125/I)L-thyroxine (T/sub 4/) ip 16 h before the experiment and samples of blood were frequently taken from polyethylene tubing inserted into the femoral artery in anaesthetized and heparin-injected animals. In each sample of plasma T/sub 4/ counts per ml were estimated with the acid of paper chromatography. Rapid decrease of circulating T/sub 4/ level was found at 20 min after iv injection of thiocyanate, iodide, fluoroborate, theophylline and salicylate and a dose-response relationship was established between such a decrease and the administered dose of salicylate (5-160 mg/400 g b.w.). A similar decrease was observed at 60 min after ip injection of some general anaesthetics or tranquilizers. An increase of T/sub 4/ fractional disposal rate was found between 120 and 480 min after the administration of some of the anaesthetics and this effect was abolished by the administration of thiocyanate. It was concluded that there are two different effects of drugs on the circulating T/sub 4/ level: 1. the immediate effect resulting apparently from a decreased plasma protein binding. 2. the prolonged effect which presumably results from the increased turnover of T/sub 4/ by peripheral tissues, the metabolic basis of which remains unexplained.

Thyroxine administration to infants of less than 30 weeks' gestational age does not increase plasma triiodothyronine concentrations

NARCIS (Netherlands)

van Wassenaer, A. G.; Kok, J. H.; Endert, E.; Vulsma, T.; de Vijlder, J. J.

1993-01-01

Very preterm infants (less than 30 weeks' gestational age) were treated with thyroxine in three different dosage schemes: 10, 8 and 6 micrograms.kg-1 birthweight.day-1 during the first 6 weeks of life. The aim was to prevent transient hypothyroxinemia of the preterm infant. Plasma levels of

Effect of intravenous injection of galanin on plasma concentrations ...

African Journals Online (AJOL)

STORAGESEVER

2008-10-06

Oct 6, 2008 ... The goal of this study was to determine whether intravenously galanin injection effect on plasma concentrations of growth hormone (GH), thyroxine (T4), triiodothyronine (T3) and milk production in the. Saanen goats. Fifteen Saanen goats were randomly divided into 5 groups (n = 3 in each group). Each.

Biosensor discovery of thyroxine transport disrupting chemicals

International Nuclear Information System (INIS)

Marchesini, Gerardo R.; Meimaridou, Anastasia; Haasnoot, Willem; Meulenberg, Eline; Albertus, Faywell; Mizuguchi, Mineyuki; Takeuchi, Makoto; Irth, Hubertus; Murk, Albertinka J.

2008-01-01

Ubiquitous chemicals may interfere with the thyroid system that is essential in the development and physiology of vertebrates. We applied a surface plasmon resonance (SPR) biosensor-based screening method for the fast screening of chemicals with thyroxine (T4) transport disrupting activity. Two inhibition assays using the main thyroid hormone transport proteins, T4 binding globulin (TBG) and transthyretin (TTR), in combination with a T4-coated biosensor chip were optimized and automated for screening chemical libraries. The transport protein-based biosensor assays were rapid, high throughput and bioeffect-related. A library of 62 chemicals including the natural hormones, polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs) and metabolites, halogenated bisphenol A (BPA), halogenated phenols, pharmaceuticals, pesticides and other potential environmentally relevant chemicals was tested with the two assays. We discovered ten new active compounds with moderate to high affinity for TBG with the TBG assay. Strikingly, the most potent binding was observed with hydroxylated metabolites of the brominated diphenyl ethers (BDEs) BDE 47, BDE 49 and BDE 99, that are commonly found in human plasma. The TTR assay confirmed the activity of previously identified hydroxylated metabolites of PCBs and PBDEs, halogenated BPA and genistein. These results show that the hydroxylated metabolites of the ubiquitous PBDEs not only target the T4 transport at the TTR level, but also, and to a great extent, at the TBG level where most of the T4 in humans is circulating. The optimized SPR biosensor-based transport protein assay is a suitable method for high throughput screening of large libraries for potential thyroid hormone disrupting compounds

Biosensor discovery of thyroxine transport disrupting chemicals.

Science.gov (United States)

Marchesini, Gerardo R; Meimaridou, Anastasia; Haasnoot, Willem; Meulenberg, Eline; Albertus, Faywell; Mizuguchi, Mineyuki; Takeuchi, Makoto; Irth, Hubertus; Murk, Albertinka J

2008-10-01

Ubiquitous chemicals may interfere with the thyroid system that is essential in the development and physiology of vertebrates. We applied a surface plasmon resonance (SPR) biosensor-based screening method for the fast screening of chemicals with thyroxine (T4) transport disrupting activity. Two inhibition assays using the main thyroid hormone transport proteins, T4 binding globulin (TBG) and transthyretin (TTR), in combination with a T4-coated biosensor chip were optimized and automated for screening chemical libraries. The transport protein-based biosensor assays were rapid, high throughput and bioeffect-related. A library of 62 chemicals including the natural hormones, polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs) and metabolites, halogenated bisphenol A (BPA), halogenated phenols, pharmaceuticals, pesticides and other potential environmentally relevant chemicals was tested with the two assays. We discovered ten new active compounds with moderate to high affinity for TBG with the TBG assay. Strikingly, the most potent binding was observed with hydroxylated metabolites of the brominated diphenyl ethers (BDEs) BDE 47, BDE 49 and BDE 99, that are commonly found in human plasma. The TTR assay confirmed the activity of previously identified hydroxylated metabolites of PCBs and PBDEs, halogenated BPA and genistein. These results show that the hydroxylated metabolites of the ubiquitous PBDEs not only target the T4 transport at the TTR level, but also, and to a great extent, at the TBG level where most of the T4 in humans is circulating. The optimized SPR biosensor-based transport protein assay is a suitable method for high throughput screening of large libraries for potential thyroid hormone disrupting compounds.

Clinical significance of two-step magnetic radioimmunoassay for determining serum free T3 and free T4

International Nuclear Information System (INIS)

Chen Bing

1996-01-01

The concentrations of the serum free T 3 (FT 3 ), free T 4 (FT 4 ), total triodothyronine (TT 3 ), total thyroxine (TT 4 ) and thyrotropin (TSH) are determined for 355 cases of normal persons, pregnant women and various thyropathetic patients. The normal values of FT 3 and FT 4 are 2.0-8.5 pmol/l, and 9.5-26.5 pmol/l, respectively. Neither FT 3 nor FT 4 is affected by the thyroxine combined with globulin (TBG), which is of unique diagnostic value for those with variable TBG (such as pregnant women hyperthyroidism, hypothyroidism, etc.), FT 3 and FT 4 are the most sensitive indices for diagnosis of hyperthyroidism, and hypothyroidism, respectively. In addition, FT 3 and FT 4 can greatly contribute to the observation of curative effectiveness under treatment

Solid Phase Radioimmunoassay for Measuring Serum Triiodothyronine and Thyroxine using Different Preparations of Their Labeled Hormones

International Nuclear Information System (INIS)

El Kolaly, M.T; Mehany, N.L; Ayyoub, S.M.; Hassan, S.E.M.

2005-01-01

The goal of the present work was oriented to prepare stable polystyrene coated tubes for direct radioimmunoassay (RIA) of triiodothyronine (T 3 ) and thyroxine (T 4 ) in human serum or plasma. Coating process was performed using sheep polyclonal antisera specific for each of T 3 and T 4 . The stability study showed that these tubes could be stored for up to one year at 4 degree without any appreciable reduction in their binding. The preparations of 25 I-T 3 and 125 I-T 4 were carried out by two different methods [chloramine-T(Ch-T) and iodogen] . It was found that Ch-T method gave approximately the same results as iodogen method. Twenty five samples of different thyroid status were assayed for T 3 and T 4 using the present systems and with commerically available kits (coated tubes, DPC). The statistical analysis revealed good correlations between the results from the present systems using T 3 and T 4 tracers prepared by Ch-T and iodogen methods and The DPC kits. This may be extremely helpful in diagnosis and proper management of thyroid dysfunctions

Iodine versus thyroxine in treatment of simple goiter in sudan

International Nuclear Information System (INIS)

Hassan, A.M; Khangi, F.A; Ali, N.I.; Besheir, S.O.; Eltom, M.A.

2003-01-01

This study was designed to update the existing information concening goiter prevalence and iodine deficiency disorders in omdurman city and to compare the effects of thyroxine versus iodine in the treament of simlpe goiter. Thyroxine in different doses is commonly used in treatment of simple goiter in Sudan. The goiter survey was conducted in Omdurman secondary school for girls (Khartoum state). Of the goitrous subjects 99 girls were selected to participate in the treament protocol. A control group of 54 non-goitrous subjects from the same school were also included. The goitrous subjects were divided randomly into two groups receiving either daily dose of 100 μg thyroxine for six months or a single dose of 400 mg of oral iodine in the form of iodized oil. Blood and urine samples were collected from the goitrous and control group and recollected from the goitrous subjects every six weeks for six months. Goiter size was assessed at 3,6 and 14 months after the commencement of the treament. Blood samples were analyzed for serum level of T4,T3 and TSH using sensitive radioimmunoassay techniques. Urine samples were analyzed for urinary iodine excretion. Goiter was found in 139 students out of 1034, (13.4%). They were all euthyroid with simple diffuse goiter.T4 in the goitrous group (93.3±26.9 nmole /L (mean±SD)) was significanty lower than in the control group (106.4±18.2nmole/L,p<0.05). T3 was significantly higher in the goitrous (1.6±0.4 nmole/L) than in the control group (1.3±0.3 nmole/L,p<0.05) while there was no significant difference in the mean serum TSH or urinary iodine excretion between the two groups. More than 70% of the goitrous and the control subjects excreted 2 μg 1 / dI or less. Of the subjects treated with thyroxine 87.8% showed complete disappearance or definite regression of the goiter size compared with 90% of those received iodine after the treament.(Author) =

T/sub 4/ radioimmunoassay with ion-exchange resin separation

Energy Technology Data Exchange (ETDEWEB)

Michael, J D; Modha, K [Hoechst Pharmaceuticals Research Ltd., Milton Keynes (UK)

1977-05-28

An explanation is provided for the reports of falsely low values of serum-thyroxine (T/sub 4/) measured by radioimmunoassay (RIA), particularly in sera containing raised concentrations of thyroxine-binding globulin (TBG) (Burr, W.A., Evans, S.E., Hogan, T.C., 1977, Lancet, April 2, 757). A re-examination of the assay technique used in commercial RIA kits ('RIA-gnost T/sub 3/' and 'RIA-gnost T/sub 4/', Behring Diagnostics) showed that blocking of binding proteins by 8-anilino-1-naphthalene sulphonic acid (ANS) was incomplete in sera with raised TBG levels. Spectroscopic determination of the blocker concentration during the time the solution was in contact with the ion exchange resin showed that 98% of the ANS was removed from solution by 10 min contact with the resin, yet 60 min was required to absorb the free T/sub 4/. There was therefore ample time for unblocked TBG to recombine with free T/sub 4/ which was then misclassified as antibody-bound T/sub 4/. The assay technique used in the kits was therefore modified. The less polar TBG blocking agent, ethylmercurithiosalicylate (merthiolate), replaced ANS and it was demonstrated that accurate T/sub 3/ and T/sub 4/ measurements in high TBG sera could be made by resin-separation RIA without resorting to prior denaturation or alcohol extraction.

Transport of thyroxine across the blood-brain barrier is directed primarily from brain to blood in the mouse

International Nuclear Information System (INIS)

Banks, W.A.; Kastin, A.J.; Michals, E.A.

1985-01-01

The role of the blood-brain barrier (BBB) in the transport of thyroxine was examined in mice. Radioiodinated (hot thyroxine (hT 4 ) administered icv had a half-time disappearance from the brain of 30 min. This increased to 60 min (p 4 ). The Km for this inhibition of hT 4 transport out of the brain by cT 4 was 9.66 pmole/brain. Unlabeled 3,3',5 triiodothyronine (cT 3 ) was unable to inhibit transport of hT 4 out of the brain, although both cT 3 (p 4 (p 3 ) to a small degree. Entry of hT 4 into the brain after peripheral administration was negligible and was not affected by either cT 4 nor cT 3 . By contrast, the entry of hT 3 into the brain after peripheral administration was inhibited by cT 3 (p 4 (p < 0.01). The levels of the unlabeled thyroid hormones administered centrally in these studies did not affect bulk flow, as assessed by labeled red blood cells (/sup 99m/Tc-RBC), or the carrier mediated transport of iodide out of the brain. Likewise, the vascular space of the brain and body, as assessed by /sup 99m/Tc-RBC, was unchanged by the levels of peripherally administered unlabeled thyroid hormones. Therefore, the results of these studies are not due to generalized effects of thyroid hormones on BBB transport. The results indicate that in the mouse the major carrier-mediated system for thyroxine in the BBB transports thyroxine out of the brain, while the major system for triiodothyronine transports hormone into the brain. 14 references, 3 figures, 2 tables

Serum thyroxine concentrations after radioactive iodine therapy in cats with hyperthyroidism

International Nuclear Information System (INIS)

Meric, S.M.; Hawkins, E.C.; Washabau, R.J.; Turrel, J.M.; Feldman, E.C.

1986-01-01

Thirty-one cats with hyperthyroidism were given one dose of radioactive iodine (131I) IV. Serum thyroxine (T4) concentrations were measured before treatment in all cats, at 12-hour intervals after treatment in 10 cats, and at 48-hour intervals after treatment in 21 cats. Serum T4 concentrations also were measured one month after 131 I therapy in 29 cats. Activity of 131I administered was 1.5 to 6.13 mCi, resulting in a dose of 20,000 rads to the thyroid. Serum T4 concentrations before 131 I administration were 5.3 to 51.0 micrograms/dl, with a median T4 concentration of 11.0 micrograms/dl. Serum T4 decreased most rapidly during the first 3 to 6 days after treatment. Sixteen cats (55%) had normal serum thyroxine concentrations by day 4 after 131I administration, and 23 cats (74%) were euthyroxinemic by day 8 after treatment. One month after administration of 131I, the 29 cats evaluated were clinically improved, and 24 (83%) of the 29 cats evaluated had normal serum T4 concentrations, 3 cats (10%) remained hyperthyroxinemic, and 2 cats (7%) were hypothyroxinemic. Therefore, administration of 131I was a safe and effective method to quickly decrease serum T4 concentrations in hyperthyroid cats

Triiodothyronine and thyroxine in urine. I. Measurement and application.

Science.gov (United States)

Shakespear, R A; Burke, C W

1976-03-01

Urinary triiodothyronine (T3) and thyroxine (T4) were measured by RIA, and T4 was also measured by competitive protein binding (CPB). pH 1-hydrolysable conjugates were 48% of total urinary T3, and enzyme- or pH 1-hydrolysable conjugates were 55% and 61% of total urinary T4. The mean unconjugated T3 excretion was 34.3 ng/h (0.99 mug T3/g creatinine) in normal subjects (no day-night rhythm found), 1.56 mug/g in late pregnancy, 0.82 mug/g in neonates (1-12 days), and was also unchanged in persons with high or low thyroxine-binding globulin (TBG). In thyrotoxicosis, mean T3 excretion was 281 ng/h, no values being in the normal range. In primary hypothyroidism it was 18.3 ng/h, but over half the values were in the normal range. The mean urinary unconjugated T4 was 82.2 ng/h (1.37 mug T4/g creatinine) in normal subjects, 1.6 mug/g in neonates, and unchanged in persons with high or low TBG, except that in pregnancy high values were compatible with increases protein excretion. Apparently increased day-time T4 excretion compared with night-time excretion may also be due to changes in protein excretion rate. The mean T4 in thyrotoxicosis was 337 ng/h (12% of values in the normal range) and 32.8 ng/h in primary hypothyroidism (over half the normal range). All the assays, especially that of T4 by CPB gave readings which were incorrect with protein concentrations above 100 mg/l. Urinary T3 and T4 assays for clinical purposes have few practical advantages over serum assays, despite the relationship of urine T3 and T4 to serum unbound levels.

Diagnostic Evaluation of Effective Thyroxine Ratio

International Nuclear Information System (INIS)

Lee, Myung Chul; Choi, Sang Jae; Ro, Heung Kyu; Lee, Hong Kyu; Koh, Chang Soon; Lee, Mun Ho

1975-01-01

The purpose of the present study is to evaluate the diagnostic value of the ETR test as compared to other thyroid function tests in normal persons, patients with thyroid disorders and patients with alterations of thyroxine-binding proteins. The ETR values were obtained from 35 cases as normal control, 63 hyperthyroid patients, 56 euthyroid patients, 23 hypothyroid patients, 10 pregnant women, 5 women taking oral contraceptive medication, 8 liver cirrhosis patients and 4 nephrotic syndrome patients. The results obtained were as follows. 1) The mean value of ETR obtained from the normal controls was 0.99±0.06. 2) The mean ETR values of various thyroid states were 1.25±0.16 in hyperthyroidism, 0.99±0.08 in euthyroidism and 0.82±0.05 in hypothyroidism and significant difference was found between these groups. 3) Seven out of 63 hyperthyroid patients (11.1%) and 2 out of 23 hypothyroid patients (8.7%) had ETR values within normal range and among the 56 euthyroid patients 6 (10.7%) had ETR values outside normal range, so the diagnostic compatibility of ETR was 89.4% in thyroid diseases. 4) Even though the ETR value was well correlated with 131 I-thyroid uptake rate, serum T 3 resin uptake rate and serum T 4 , a high positive correlation was found (r=0.79) between ETR and T 7 . 5) The mean ETR values from patients with alteration in TBG binding capacity were 0.99±0.05 in pregnant women, 0.98±0.04 in women with oral contraceptive medication, 1.04±0.09 in liver cirrhosis patients and 0.94±0.02 in nephrotic syndrome patients and most of them (85.2%) had ETR values within normal range. Our results, therefore, suggests that the ETR estimation does offer the simplest and most reliable single procedure for the screening and diagnosis of various thyroid diseases as a indirect indicator of serum-free thyroxine concentration without essential influence of changes in the thyroxine-binding proteins in serum.

Diagnostic Evaluation of Effective Thyroxine Ratio

Energy Technology Data Exchange (ETDEWEB)

Lee, Myung Chul; Choi, Sang Jae; Ro, Heung Kyu; Lee, Hong Kyu; Koh, Chang Soon; Lee, Mun Ho [Seoul National University College of Medicine, Seoul (Korea, Republic of)

1975-09-15

The purpose of the present study is to evaluate the diagnostic value of the ETR test as compared to other thyroid function tests in normal persons, patients with thyroid disorders and patients with alterations of thyroxine-binding proteins. The ETR values were obtained from 35 cases as normal control, 63 hyperthyroid patients, 56 euthyroid patients, 23 hypothyroid patients, 10 pregnant women, 5 women taking oral contraceptive medication, 8 liver cirrhosis patients and 4 nephrotic syndrome patients. The results obtained were as follows. 1) The mean value of ETR obtained from the normal controls was 0.99+-0.06. 2) The mean ETR values of various thyroid states were 1.25+-0.16 in hyperthyroidism, 0.99+-0.08 in euthyroidism and 0.82+-0.05 in hypothyroidism and significant difference was found between these groups. 3) Seven out of 63 hyperthyroid patients (11.1%) and 2 out of 23 hypothyroid patients (8.7%) had ETR values within normal range and among the 56 euthyroid patients 6 (10.7%) had ETR values outside normal range, so the diagnostic compatibility of ETR was 89.4% in thyroid diseases. 4) Even though the ETR value was well correlated with {sup 131}I-thyroid uptake rate, serum T{sub 3} resin uptake rate and serum T{sub 4}, a high positive correlation was found (r=0.79) between ETR and T{sub 7}. 5) The mean ETR values from patients with alteration in TBG binding capacity were 0.99+-0.05 in pregnant women, 0.98+-0.04 in women with oral contraceptive medication, 1.04+-0.09 in liver cirrhosis patients and 0.94+-0.02 in nephrotic syndrome patients and most of them (85.2%) had ETR values within normal range. Our results, therefore, suggests that the ETR estimation does offer the simplest and most reliable single procedure for the screening and diagnosis of various thyroid diseases as a indirect indicator of serum-free thyroxine concentration without essential influence of changes in the thyroxine-binding proteins in serum.

Liquid L-thyroxine versus tablet L-thyroxine in patients on L- thyroxine replacement or suppressive therapy: a meta-analysis.

Science.gov (United States)

Laurent, Irakoze; Tang, Siying; Astère, Manirakiza; Wang, Kan Ran; Deng, Shuhua; Xiao, Ling; Li, Qi Fu

2018-03-23

To compare the effectiveness of liquid L-T4 (L-thyroxine) and tablet L-T4 in patients on L-T4 replacement or suppressive therapy. The Cochrane Library, PubMed, Embase, and Web of Science databases were searched to identify relevant articles. All prospective or randomized controlled studies (RCTs) comparing liquid L-T4 and tablet L-T4 in patients on L-T4 replacement or suppressive therapy were included in the analysis. Overall, the initial search of the four databases identified 1278 published studies; of these, eight studies were ultimately included in the meta-analysis. TSH (thyroid stimulating hormone) levels were significantly suppressed in patients on liquid L-T4 compared with those on tablet L-T4, in patients on L-T4 suppressive therapy with L-T4 malabsorption (Mean Difference (MD) = -2.26, 95% Confidence Interval (CI): -3.59, -0.93; P = 0.0009)). However, liquid L-T4 and tablet L-T4 did not show a statistically significant difference in patients on L-T4 suppressive therapy without malabsorption (MD = 0.08, 95% CI: -0.31, 0.47; P = 0.69). TSH levels were significantly normalized in patients on liquid L-T4 compared with those on tablet L-T4, in Patients on L-T4 replacement therapy with L-T4 malabsorption (MD = -3.20, 95% CI: -5.08, -1.32; P = 0.0009). However, liquid L-T4 and tablet L-T4 did not show a statistically significant difference in patients on L-T4 replacement therapy without malabsorption (MD = 0.91, 95% CI: -0.03, 1.86; P = 0.06). Liquid L-T4 is more efficient than tablet L-T4 in patients on L-T4 replacement or suppressive therapy with malabsorption. No significant differences were observed in patients without malabsorption. Further studies should be conducted to verify these findings.

Iodine versus thyroxine in treatment of simple goiter in sudan

International Nuclear Information System (INIS)

Eltom, M.A.; Ali, N.

2003-01-01

This study was designed to update the existing information concerning goiter prevalence and iodine deficiency disorders in Omdurman city and to compare the effects of thyroxine versus iodine in the treatment of simple goiter. Thyroxine in different doses is commonly used in treatment of sample goiter in sudan. This goiter survey was conducted in Omdurman secondary school for girls (Khartoum state). Of the goitrous subjects 99 girls were selected to participate in the treatment protocol. A control group of 54 non-goitrous subjects from the same school were also included. This goitrous subjects were divided randomly into two groups receiving either daily dose of 100 μg thyroxine for six months or a single dose of 400 mg of oral iodine in the form iodized oil. Blood and urine samples were collected from the goitrous and control group and recollected from the goitrous subjects every six weeks for six months. Goiter size was assessed at 3,6 and 14 months after the commencement of the treatment. Blood samples were analyzed for serum level of T4, T3 and TSH using sensitive radioimmunoassay techniques. Urine samples were analyzed for urinary iodine excretion. Goiter was found in 139 students out of 1034, (13.4%). They were all euthyroid with simple diffuse goiter. T4 in the goitrous group (93.3±26.9 n mole/L (mean±SD)) was significantly lower than in the control group (106.4±18.2 n mole /L, p<0.05). T3 was significantly higher in the goitrous (1.3 ±0.3 n mole/L, p<0.05) while there was no significant difference in the mean serum TSH or urinary iodine excretion between the two groups. More than 70% of goitrous and the control subjects excreted 2 μg I /dl or less. Of the subjects treated with thyroxine 87.8% showed complete disappearance or definite regression of the goiter sized compared with 90% of those received iodine after the treatment

Reference interval of thyroxine and thyrotropin of healthyterm ...

African Journals Online (AJOL)

Objective: To establish a local Reference Interval of Serum Thyroxine (T4) and Serum Thyroid stimulating Hormone(TSH) of healthy Nigerian Newborns in Jos University Teaching Hospital Jos. Materials and Methods: One hundred and sixty healthy term Nigerian Newborns who fulfilled the criteria for inclusion were ...

Corticosterone and thyroxine in cold-stunned Kemp's ridley sea turtles (Lepidochelys kempii).

Science.gov (United States)

Hunt, Kathleen E; Innis, Charles; Rolland, Rosalind M

2012-09-01

Kemp's ridley sea turtles (Lepidochelys kempii), a critically endangered species, frequently strand on the shores of Cape Cod (Massachusetts, USA) in late autumn in a state of "cold-stunning" exhibiting low body temperature and related clinical issues. Stranded turtles are transported to the New England Aquarium (Boston, Massachusetts, USA) for treatment and rehabilitation. This study tested the hypothesis that cold-stunned sea turtles might exhibit high corticosterone ("stress hormone") or low thyroxine (which is often affected by temperature), or both, and that monitoring of both hormones may be useful for assessing recovery. In a retrospective analysis, 87 archived plasma samples were assayed from 56 cold-stunned juvenile Kemp's ridley sea turtles for corticosterone and free thyroxine (fT4). Upon admission, mean corticosterone was the highest yet reported for a population of sea turtles (39.3 +/- 2.5 ng/ml; mean +/- standard error of the mean [SEM]) and fT4 was usually undetectable. On admission, corticosterone was negatively correlated with white blood cell count but was not correlated with blood glucose. There were no differences in either hormone between survivors and nonsurvivors on admission. After 18+ days in recovery, surviving turtles' corticosterone dropped significantly to levels typical of baseline in other species (0.9 +/- 1.0 ng/ml) while fT4 increased significantly (1.3 +/- 1.5 pg/ml). During recovery, corticosterone was positively correlated with blood glucose and was not correlated with white blood cell count. Turtles that showed persistent deficits in feeding, activity, or both during recovery had significantly lower fT4 than did turtles with no such deficits. The "high corticosterone, low fT4" endocrine profile seen on admission may be a useful marker of cold-stunning in this and other species. Further studies are necessary to determine whether low thyroid hormones play a causal role in deficits in feeding and activity during recovery

Preparation and separation of the glucuronide and sulfate conjugates of thyroxine and triiodothyronine

International Nuclear Information System (INIS)

Hays, M.T.; Hsu, L.

1987-01-01

An enzymatic method for synthesis of labelled thyroxine glucuronide (T4G) and triiodothyronine glucuronide (T3G) from labelled thyroxine (T4) and triiodothyronine (T3) is presented. The synthetic glucuronides are completely digested by beta-glucuronidase, with recovery of the parent T4 or T3. They have distinctive elution patterns on HPLC and on Sephadex G25 chromatography, and can be clearly separated from T4 and T3 as well as from synthetic T4 sulfate (T4S) and T3 sulfate (T3S). On LH 20 chromatography, elution of T4G and T3G is intermediate between that of T4 and T3 and that of T4S and T3S. T3G can be well separated from other thyronines by HPLC alone, but T4G coelutes with rT3 on HPLC; these are then separated by adding a Sephadex G25 chromatography step. Biosynthetic 131 I-T3G and 125 I-T4G from the bile of a cat given 131 I-T3 and 125 I-T4 had similar HPLC chromatographic patterns to those of synthetic T3G and T4G. That the identified peaks from analysis of the bile were indeed T3G and T4G was confirmed by recovery of the parent T3 and T4 after beta-glucuronidase digestion

The concentration of glucose, insuline, thyroxine (T4), triiodthyronine (T3) and gastrine in the maternal blood, in the umbilical cord blood of their outcomes in the neonatal blood samples

International Nuclear Information System (INIS)

Osuch-Jaczewska, R.; Tomala, J.; Adamska, S.; Bielecka, W.; Mikulska, M.; Kalacinska, M.; Sieron, G.

1978-01-01

In the blood samples collected from the mothers, from the umbilical cord of their outcomes and from these neonates after 24 hours of life following estimations were performed collaterally: The concentration of insulin in 50 mothers and their fetuses and in 34 neonates, concentration of thyroxine (T 4 ) in 70 mothers and their fetuses and in 32 neonates, triiodothyronine binding coefficient (WWT 3 ) in 60 mothers and their fetuses and neonates, concentration of gastrine in 23 mothers and their fetuses and in 5 neonates. Besides that the concentration of glucose in total blood was established in 300 mothers - their fetuses and neonates. The insuline, WWT 3 and gastrine were estimated by radioimmune techniques and T 4 by radiocompetitive technique. The glucose concentration - with the aid of o-toluidine method. Basing on the results, the paper suggests that the fetus and the newborn represent independent unit in the aspect of regulation of the glucose concentration, secretion of insuline, T 3 , T 4 and gastrine, notwithstanding the possibility of transplacental passage of these hormones exists the correlation coefficients between the maternal and fetal blood concentrations of insuline, T 4 and WWT 3 were significant. The cord-blood glucose concentration exhibits a marked correlation with the maternal glicemia. Physiologic, asymptomatic hyperinsulinemia and hyperthyreosis and an increase of gastrine concentration demonstrate the presence, in the fetal and neonatal organisms, of certain compensatory-regulating mechanisms stimulating and inhibiting with feed-back properties, which guarantee the environmental homeostasis. (author)

Serum TBG and T4 concentration in non-thyroidal diseases

International Nuclear Information System (INIS)

Sasaki, Y.; Tobari, C.; Sekita, N.; Onodera, Y.; Asazu, M.; Someya, K.

1983-01-01

Routinely available radioassay kits have recently enabled the measurement of serum concentrations of thyroxine binding globulin (TBG) and thyroxine (T 4 ), both total (TT 4 ) and free (FT 4 ) in various disease conditions. Serum TBG and T 4 level were measured in variety of non-thyroidal diseases, of which significance was evaluated in comparison with that in thyroidal diseases. Abnormal serum TBG concentrations in various non-thyroidal diseases and pregnancy result in abnormal serum TT 4 levels, which may cause difficulty in differentiation of these conditions from hyper- or hypothyroidal states. Serum FT 4 levels give better indicator than TT 4 , though the difference among RIA kits are considerably large. However, measurement of serum FT 4 levels alone is not sufficient to distinguish non-thyroidal disease from thyroidal diseases with abnormal thyroidal function. The differentiation has to be based on the combination of clinical findings and results of multiple thyroidal function tests

Behaviour of hormone parameters and equivalent iodide clearance (TcTu) on suppressive T4 treatment of enthyroid struma

International Nuclear Information System (INIS)

Greis, W.

1978-01-01

84 patients with euthyroid diffuse struma were stabilised at the individually necessary thyroxine dose by means of TcTU, T 4 , and NTR. As long-term medication, 100μg l-thyroxin were required in 143% of the patients, 150 μg in 83.3% of the patients, and 200 μg in 2.4% of the patients. After 8 to 12 weeks of therapy, the TcTU as an estimate of the iodide clearance was suppressed to 0.1 to 3.5 ( x +- s). T 4 and NTR values were near the upper limit of the normal at a normal T 3 level. After administration of 150 μg thyroxine per day for 12 weeks and 200μg thyroxine for 4 weeks, TcTU is suppressed to a comparable extent while the weaker suppressive effect of a 12 weeks' medication with 100μg thyroxine could not be improved even by a prolonged therapy. After one year of treatment, calculations of the thyroid surface in scintiscans showed a successful therapy in 82% of the patients while the circumference of the neck had become smaller only in 60% of the patients. Therapy was generally less successful in patients over 18 years of age. (orig.) [de

Preparation of quality control samples for thyroid hormones T3 and T4 in radioimmunoassay techniques

International Nuclear Information System (INIS)

Ahmed, F.O.A.

2006-03-01

Today, the radioimmunoassay becomes one of the best techniques for quantitative analysis of very low concentration of different substances. RIA is being widely used in medical and research laboratories. To maintain high specificity and accuracy in RIA and other related techniques the quality controls must be introduced. In this dissertation quality control samples for thyroid hormones (Triiodothyronine T3 and Thyroxin T4), using RIA techniques. Ready made chinese T4, T3 RIA kits were used. IAEA statistical package were selected.(Author)

Comparison of Amerlex, NML, and Ames total thyroxine and triiodothyronine radioimmunoassay kits

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Wilke, T J; Turnbull, P A [Commonwealth Pathology Lab., Toowoomba (Australia). Dept. of Endocrinology

1982-03-01

An evaluation of the Amerlex system for determination of total thyroxine (T4) and total triiodothyronine (T3) is described. The within- and between-batch precisions were acceptable, and analyses of quality control material and linearity studies demonstrated good accuracy at the clinical decision levels. The correlations obtained with NML and Ames T4 and T3 kit methods were highly significant. The Amerlex T4 and T3 methods are rapid, technically simple, and, coupled with excellent precision and accuracy, present significant advantages.

Comparison of Amerlex, NML, and Ames total thyroxine and triiodothyronine radioimmunoassay kits

International Nuclear Information System (INIS)

Wilke, T.J.; Turnbull, P.A.

1982-01-01

An evaluation of the Amerlex system for determination of total thyroxine (T4) and total triiodothyronine (T3) is described. The within- and between-batch precisions were acceptable, and analyses of quality control material and linearity studies demonstrated good accuracy at the clinical decision levels. The correlations obtained with NML and Ames T4 and T3 kit methods were highly significant. The Amerlex T4 and T3 methods are rapid, technically simple, and, coupled with excellent precision and accuracy, present significant advantages. (author)

Intraindividual variation of triiodothyronine, thyroxine, thyrotropin and thyroxine-binding globulin in fasting serum from healthy men

International Nuclear Information System (INIS)

Liappis, N.; Hoffmann, U.; Rao, M.L.

1986-01-01

The concentrations of triiodothyronine, thyroxine, thyrotropin and thyroxine-binding globulin were determined in fasting serum from 11 healthy men (age 18-25 years) by radioimmunoassays conducted over a period of 4 weeks on 5 consecutive days per week. The concentrations of thyroxine and thyroxine-binding globulin were very consistent intraindividually, with coefficients of variation of 7.84% and 9.37%, respectively. The triiodothyronine and thyrotropin levels showed significant intraindividual variability with coefficients of variation of 18.38% and 51.85%, respectively. These results point to the type of difficulties encountered in judging serum values, namely intraindividual variations over a given period of time. (orig.) [de

A solid-phase-radioimmunoassay for total serum thyroxine

International Nuclear Information System (INIS)

Moedder, G.; Sokolowski, G.

1978-01-01

A new solid phase radioimmunoassay for total serum thyroxine was evaluated over a longer time under clinical routine conditions and compared with an established test system. The results show up that the T 4 values are precise, reliable and reproducible, the is incomplicate to handle and well suitable for semiautomatic pipetting systems. (orig.) 891 MG [de

Rapid purification of tri-iodothyronine and thyroxine protein conjugates for antibody production.

Science.gov (United States)

Burke, C W; Shakespear, R A

1975-04-01

Thyroxine (T-4) and tri-iodothyronine (T-3) were coupled to human serum albumin (HSA) with carbodi-imide. By adsorption chromatography on Sephadex G-25, fractions containing purified conjugate, but not reversibly-bound T-3 or T-4, were obtained, and this procedure took 5 h; considerably less than the conventional dialysis technique. Highly specific high-titre antisera were produced in rabbits and guinea-pigs by injection of these fractions in Freund's adjuvant.

Basic and clinical evaluation of thyroxine radioimmunoassay kit. I. T-4 RIA kit

Energy Technology Data Exchange (ETDEWEB)

Bunko, H; Hisada, K [Kanazawa Univ. (Japan). Hospital

1976-02-01

The T/sub 4/ RIA kit is based on single antibody radioimmunoassay and utilizes a resin-sponge to separate free T/sub 4/-/sup 125/I from the incubation mixture. The use of the sodium salt of trichloroacetic acid (TBG inhibitor) permits direct radioimmunoassay of T/sub 4/ without a tedious extraction procedure. The T/sub 4/ RIA kit needs only 0.05 ml of patient serum and one hour of incubation to measure T/sub 4/. The TBG inhibitior was equivalent to 5.1 ..mu..g% of T/sub 4/ in displacing radioactive T/sub 4/ from TBG in a CPBA(Res-O-Mat T/sub 4/) system, and the TBG inhibitor volume of 0.5 ml (ten times of serum) was needed to measure a high T/sub 4/ concentration serum. The change of incubation temperature was more affected on the standard curve than that of incubation time. Correlation of the T/sub 4/ value between radioimmunoassay and CPBA in 69 patients was good (r=0.88612, p<0.01) and showed a slightly higher T/sub 4/ value when measured with radioimmunoassay than CPBA (linear regression function: Y=1.17506 + 0.95766X). Correlation of T/sub 4/ between Compu-curve and conventional standard curve was excellent (r=0.9995), but a slight difference was found in both low and high T/sub 4/ concentrations. In euthyroid patients without thyroid diseases, T/sub 4/ concentration was 9.92 +- 2.66 (SD) ..mu..g% and the normal range was between 4.60 and 15.24 ..mu..g%. Reproducibility within assay was 9.9% (CV) and recovery rate was 70% when added 10 ..mu..g of T/sub 4/ and 86% when added 15 ..mu..g% of T/sub 4/. From these results, the authors concluded that radioimmunoassay of serum T/sub 4/ using the T/sub 4/ RIA kit would be a promising one, especially when measuring a large amount of samples per assays.

Thyroid function in children and adolescents with Hashimoto’s thyroiditis after l-thyroxine discontinuation

Directory of Open Access Journals (Sweden)

Giorgio Radetti

2017-04-01

Full Text Available Objective: Thyroid function may recover in patients with Hashimoto’s thyroiditis (HT. Design: To investigate thyroid function and the need to resume l-thyroxine treatment after its discontinuation. Setting: Nine Italian pediatric endocrinology centers. Patients: 148 children and adolescents (25 m and 123 f with HT on treatment with l-thyroxine for at least one year. Intervention and main outcome measure: Treatment was discontinued in all patients, and serum TSH and fT4 concentrations were measured at the time of treatment discontinuation and then after 2, 6, 12 and 24 months. Therapy with l-thyroxine was re-instituted when TSH rose >10 U/L and/or fT4 was below the normal range. The patients were followed up when TSH concentrations were between 5 and 10 U/L and fT4 was in the normal range. Results: At baseline, TSH was in the normal range in 139 patients, and was between 5 and 10 U/L in 9 patients. Treatment was re-instituted after 2 months in 37 (25.5% patients, after 6 months in 13 patients (6.99%, after 12 months in 12 patients (8.6%, and after 24 months in an additional 3 patients (3.1%. At 24 months, 34 patients (34.3% still required no treatment. TSH concentration >10 U/L at the time of diagnosis was the only predictive factor for the deterioration of thyroid function after l-thyroxine discontinuation. Conclusions: This study confirms that not all children with HT need life-long therapy with l-thyroxine, and the discontinuation of treatment in patients with a TSH level <10 U/L at the time of diagnosis should be considered.

Concentration of glucose, insuline, thyroxine (T/sub 4/), triiodthyronine (T/sub 3/) and gastrine in the maternal blood, in the umbilical cord blood of their outcomes in the neonatal blood samples

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Osuch-Jaczewska, R; Tomala, J; Adamska, S; Bielecka, W; Mikulska, M; Kalacinska, M; Sieron, G [Slaska Akademia Medyczna, Katowice (Poland)

1978-01-01

In the blood samples collected from the mothers, from the umbilical cord of their outcomes and from these neonates after 24 hours of life the following estimations were performed collaterally: The concentration of insulin in 50 mothers and their fetuses and in 34 neonates, concentration of thyroxine (T/sub 4/) in 70 mothers and their fetuses and in 32 neonates, triiodothyronine binding coefficient (WWT/sub 3/) in 60 mothers and their fetuses and neonates, concentration of gastrine in 23 mothers and their fetuses and in 5 neonates. Besides that the concentration of glucose in total blood was established in 300 mothers - their fetuses and neonates. The insuline, WWT/sub 3/ and gastrine were estimated by radioimmune techniques and T/sub 4/ by radiocompetitive technique. The glucose concentration - with the aid of o-toluidine method. Basing on the results, the paper suggests that the fetus and the newborn represent independent unit in the aspect of regulation of the glucose concentration, secretion of insuline, T/sub 3/, T/sub 4/ and gastrine, notwithstanding the possibility of transplacental passage of these hormones exists the correlation coefficients between the maternal and fetal blood concentrations of insuline, T/sub 4/ and WWT/sub 3/ were significant. The cord-blood glucose concentration exhibits a marked correlation with the maternal glicemia. Physiologic, asymptomatic hyperinsulinemia and hyperthyreosis and an increase of gastrine concentration demonstrate the presence, in the fetal and neonatal organisms, of certain compensatory-regulating mechanisms stimulating and inhibiting with feed-back properties, which guarantee the environmental homeostasis.

Pyrroloquinoline quinone ameliorates l-thyroxine-induced hyperthyroidism and associated problems in rats.

Science.gov (United States)

Kumar, Narendra; Kar, Anand; Panda, Sunanda

2014-08-01

Pyrroloquinoline quinone (PQQ) is believed to be a strong antioxidant. In this study, we have evaluated its hitherto unknown role in l-thyroxin (L-T4 )-induced hyperthyroidism considering laboratory rat as a model. Alterations in the serum concentration of thyroxin (T4 ) and triiodothyronine (T3 ); lipid peroxidation (LPO) of liver, kidney, heart, muscles and brain; in the endogenous antioxidants such as superoxide dismutase, catalase and glutathione and in serum total cholesterol, high-density lipoprotien, triglycerides, serum glutamate pyruvate transaminase (SGPT), serum glutamate oxaloacetate transaminase (SGOT) and urea were evaluated. Administration of l-T4 (500-µg kg(-1) body weight) enhanced not only the serum T3 and T4 levels but also the tissue LPO, serum SGOT, SGPT and urea with a parallel decrease in the levels of antioxidants and serum lipids. However, on simultaneous administration of PQQ (5 mg kg(-1) for 6 days), all these adverse effects were ameliorated, indicating the potential of PQQ in the amelioration of hyperthyroidism and associated problems. Possibly, the curative effects were mediated through inhibition of oxidative stress. We suggest that PQQ may be considered for therapeutic use for hyperthyroidism after dose standardization. Copyright © 2014 John Wiley & Sons, Ltd.

Radioimmunoassay detection of levels of triiodothyronine and thyroxine in Mangalarga Marchador equine

International Nuclear Information System (INIS)

Viana, F.A.B.; Pessoa, J.M.; Biondini, J.

1991-01-01

Serum levels of triiodothyronine (T 3 ) and thyroxine (T 4 ) were determined in equine of Mangalarga Marchador breed through radioimmunoassay. Forty-two animals (17 males and 25 females), with age ranging from two to eighteen years, were utilized. The values recorded for males and females were, respectively: 101.68 ± 23.44 and 71.14 ± 18.82 ng/d l of T 3 (P 4 (P<0.05). (author). 10 refs, 1 tab

Measurement of free thyroxine and free triiodothyronine concentrations by DPC RIA kits

International Nuclear Information System (INIS)

Kasagi, Kanji; Kousaka, Tadako; Hatabu, Hiroto; Tokuda, Yasutaka; Iida, Yasuhiro; Konishi, Junji

1988-01-01

'DPC RIA' kits for measuring free triiodothyronine (T3) and free thyroxine (T4) were fundamentally and clinically studied. Standard curves for incubation temperature and time were favorable. The present kits yielded satisfactory precision and reproducibility. The upper and lower limits of the normal range for T4 were 0.88 ng/dl and 2.08 ng/dl, respectively. The serum concentration of T4 was 3.91 ng/dl or more for hyperthyroidism and 0.57 ng/dl or less for hypothyroidism, allowing discrimination between the two diseases. For T3, the upper and lower limits of the normal range were 1.45 ng/dl and 3.45 ng/dl, respectively. In pregnant women and patients with decreased or increased levels of thyroxine binding globulin (TBG), the serum T3 concentration lay within the normal range. Low free T4 and T3 levels were found in 22 % and 67 %, respectively, of patients with serious non-thyroidal illness (NTI). There was a good correlation between the present kits and the other commercially available kits. Measurements of free T3 and T4 obtained by ''Amerlex RIA'' kits tended to be lower than those by the present kits in pregnant women and NTI patients with hypoalbuminemia. In view of the simplified procedure, satisfactory precision and reproducibility, and the lack of influences of serum albumin and TBG, the present kits have a potential in routine use. (Namekawa, K.)

A Clinical Study on {sup 125}IT{sub 3} Resin Uptake Rate and Serum Thyroxin(T{sub 4}) in Hyperthyroidism

Energy Technology Data Exchange (ETDEWEB)

MooN, Ern Soo; Park, Yoh Han; Cho, Chang Ho; Park, In Soo; Lee, Chong Suk; Lee, Hak Choong [National Medical Center, Seoul (Korea, Republic of)

1978-09-15

Hyperthyroidism may be defined as those clinical conditions which result from an increase in the circulating levels of one or both thyroid hormones. Hyperthyroidism in broad sense could be classified with toxic diffuse goiter, toxic adenomatous goiter, and toxic multinodular goiter on the basis of the circulating thyroid hormone levels. For this study, the subject included 94 cases with hyperthyroidism were presented in 77 with toxic diffuse goiter, 8 with toxic adenomatous goiter, and 9 with toxic multinodular goiter on the levels of {sup 125}IT{sub 3} resin uptake rate and serum thyroxine (T{sub 4}). The observed results were as follows: 1) In the cases of hyperthyroidism including toxic diffuse goiter, toxic adenomatous goiter, and toxic multinodular goiter, 20.21% of the patients were male and 79.79% female. The majority of the patients were in 2nd to 4th decades of their lives. 2) There were objective signs clearly manifested in hyperthyroidism including toxic diffuse goiter and toxic adenomatous goiter which were rare in the multinodular goiter. The clinical signs in toxic diffuse and toxic adenomatous goiter included wide pulse pressure, tachycardia, systolic murmur, exophthalmos, tremor and warm skin etc. 3) The most frequent complaints of the patients with hyperthyroidism were palpitation, weight loss, increased appetite, perspiration, heat intolerance, nervousness, exertional dyspnea, and menstrual disturbance etc. There was no clear difference in the incidence of symptoms between toxic diffuse goiter and toxic adenomatous goiter, but there was clear difference between toxic multinodular goiter. 4) Considering of results of {sup 125}IT{sub 3} resin uptake rate and serum T{sub 4} level in toxic diffuse goiter, toxic adenomatous goiter and toxic multinodular goiter, {sup 125}IT{sub 3} resin uptake rate was 49.15+-9.94% (mean) and serum T{sub 4} 21.29+-7.04 ug/dl (mean) in toxic diffuse goiter. In toxic multinodular goiter, {sup 125}I T{sub 3} resin uptake

The effects of thyroxine on metabolism and water balance in a desert-dwelling rodent, Merriam's kangaroo rat (Dipodomys merriami).

Science.gov (United States)

Banta, Marilyn R; Holcombe, Dale W

2002-01-01

Desert-dwelling mammals such as Merriam's kangaroo rat (Dipodomys merriani) need to conserve both energy and water to survive desert conditions characterized by aridity and low productivity. The thyroid hormone thyroxine increases both basal metabolic rate and urinary water loss in mammals. Increases in basal metabolism and urinary water loss are likely to be detrimental to D. merriami, therefore the regulation of this hormone may be important. To examine the effects of thyroxine in this species, we implanted adult kangaroo rats with pellets designed to release specific doses of thyroxine at a constant rate for 90 days or a placebo pellet. We measured plasma thyroxine concentration, basal metabolic rate, food consumption, urine concentration and water loss in all implanted animals. Thyroxine implants significantly increased both plasma thyroxine and basal metabolic rate in a relatively dose-dependent manner. In response to thyroxine. kangaroo rats increased food consumption only slightly, but this small increase was sufficient to compensate for their elevated metabolic rates. Neither urine concentration nor water loss varied among treatment groups. Thyroxine increased energy expenditure but not water loss in this species.

Congenital hypothyroidism: influence of disease severity and L-thyroxine treatment on intellectual, motor, and school-associated outcomes in young adults.

Science.gov (United States)

Oerbeck, Beate; Sundet, Kjetil; Kase, Bengt F; Heyerdahl, Sonja

2003-10-01

To describe intellectual, motor, and school-associated outcome in young adults with early treated congenital hypothyroidism (CH) and to study the association between long-term outcome and CH variables acting at different points in time during early development (CH severity and early L-thyroxine treatment levels [0-6 years]). Neuropsychological tests were administered to all 49 subjects with CH identified during the first 3 years of the Norwegian neonatal screening program (1979-1981) at a mean age of 20 years and to 41 sibling control subjects (mean age: 21 years). The CH group attained significantly lower scores than control subjects on intellectual, motor, and school-associated tests (total IQ: 102.4 [standard deviation: 13] vs 111.4 [standard deviation: 13]). Twelve (24%) of the 49 CH subjects had not completed senior high school, in contrast to 6% of the control subjects. CH severity (pretreatment serum thyroxine [T4]) correlated primarily with motor tests, whereas early L-thyroxine treatment levels were related to verbal IQ and school-associated tests. In multiple regression analysis, initial L-thyroxine dose (beta = 0.32) and mean serum T4 level during the second year (beta = 0.48) predicted Verbal IQ, whereas mean serum T4 level during the second year (beta = 0.44) predicted Arithmetic. Long-term outcome revealed enduring cognitive and motor deficits in young adults with CH relative to control subjects. Verbal functions and Arithmetic were associated with L-thyroxine treatment variables, suggesting that more optimal treatment might be possible. Motor outcome was associated with CH severity, indicating a prenatal effect.

High free thyroxine levels are associated with QTc prolongation in males

NARCIS (Netherlands)

C. van Noord (Charlotte); W.M. van der Deure (Wendy); M.C.J.M. Sturkenboom (Miriam); S.M.J.M. Straus (Sabine); A. Hofman (Albert); T.J. Visser (Theo); J.A. Kors (Jan); J.C.M. Witteman (Jacqueline); B.H.Ch. Stricker (Bruno)

2008-01-01

textabstractThe literature on the effect of excess thyroid hormone on ventricular repolarization is controversial. To study whether free thyroxine (T4) and TSH are associated with QTc prolongation we conducted population-based cohort study. This study was conducted as part of the Rotterdam Study and

Clinical significance of the measurements of serum free thyroxine and free triiodothyronine concentrations

International Nuclear Information System (INIS)

Kubota, Ken; Sasaki, Norio; Takaku, Fumimaro; Uchimura, Hidemasa

1988-01-01

A commercially available ''DPC'' radioimmunoassay kit was used to study the serum concentrations of free triiodothyronine (FT3) and free thyroxine (FT4) in a series of 189 patients with various thyroid diseases and 120 healthy controls. The basal serum concentrations of FT3 and FT4 in normal controls ranged from 0.98 to 2.04 ng/dl and from 1.43 to 3.66 pg/ml, respectively. All untreated patients with Graves' disease had abnormally high FT3 and FT4 values, indicating the discrimination between hyperthyroid and normal subjects. A decreased ratio of FT4 to FT3 was observed in patients managed with antithyroid drugs. In diagnosing hypothyroidism, ''DPC'' FT4 kits were more sensitive than ''DPC'' TT4 and ''Amerlex'' FT4 kits. In the case of non-thyroid diseases, FT4 and FT3 values, as well as total T4 and total T3, were normal or decreased, with the exception of occasionally unknown high values. The interference of thyroxine binding globulin abnormablity was successfully eliminated by using new versions of ''DPC'' kits. (Namekawa, K.)

Contribution to the microchemical determination of thyroxine and triiodothyronine in urine

Energy Technology Data Exchange (ETDEWEB)

Bednar, J [Research Institute of Endocrinology, Prague (Czechoslovakia)

1980-03-20

The application of a microchemical method for the estimation of thyroxine (T/sub 4/) and triiodothyronine (T/sub 3/) in blood serum for the simultaneous determination of both hormones in urine is described. The results were corrected for possible losses during the analytical procedure using known amounts of /sup 131/I-T/sub 4/ and /sup 131/I-T/sub 3/ added to the analyzed samples. The developed method is not convenient for diagnostic purposes on account of the fact that the total concentration of both hormones and not only the percentage of hormones unbound in the form of conjugates is estimated.

A genome-wide association study of thyroid stimulating hormone and free thyroxine in Danish children and adolescents.

Directory of Open Access Journals (Sweden)

Tenna Ruest Haarmark Nielsen

Full Text Available Hypothyroidism is associated with obesity, and thyroid hormones are involved in the regulation of body composition, including fat mass. Genome-wide association studies (GWAS in adults have identified 19 and 6 loci associated with plasma concentrations of thyroid stimulating hormone (TSH and free thyroxine (fT4, respectively.This study aimed to identify and characterize genetic variants associated with circulating TSH and fT4 in Danish children and adolescents and to examine whether these variants associate with obesity.Genome-wide association analyses of imputed genotype data with fasting plasma concentrations of TSH and fT4 from a population-based sample of Danish children, adolescents, and young adults, and a group of children, adolescents, and young adults with overweight and obesity were performed (N = 1,764, mean age = 12.0 years [range 2.5-24.7]. Replication was performed in additional comparable samples (N = 2,097, mean age = 11.8 years [1.2-22.8]. Meta-analyses, using linear additive fixed-effect models, were performed on the results of the discovery and replication analyses.No novel loci associated with TSH or fT4 were identified. Four loci previously associated with TSH in adults were confirmed in this study population (PDE10A (rs2983511: β = 0.112SD, p = 4.8 ∙ 10-16, FOXE1 (rs7847663: β = 0.223SD, p = 1.5 ∙ 10-20, NR3C2 (rs9968300: β = 0.194SD, p = 2.4 ∙ 10-11, VEGFA (rs2396083: β = 0.088SD, p = 2.2 ∙ 10-10. Effect sizes of variants known to associate with TSH or fT4 in adults showed a similar direction of effect in our cohort of children and adolescents, 11 of which were associated with TSH or fT4 in our study (p<0.0002. None of the TSH or fT4 associated SNPs were associated with obesity in our cohort, indicating no pleiotropic effects of these variants on obesity.In a group of Danish children and adolescents, four loci previously associated with plasma TSH concentrations in adults, were associated with plasma TSH

Distribution of /sup 125/I-thyroxine in different organs and tissues of dietically obese rats

Energy Technology Data Exchange (ETDEWEB)

Hartmann, K.; Voss, C.; Huebner, G. (Ernst-Moritz-Arndt-Universitaet, Greifswald (German Democratic Republic)); Weber, A. (Ernst-Moritz-Arndt-Universitaet, Greifswald (German Democratic Republic). Radiologische Klinik)

1985-04-01

The distribution of /sup 125/I-thyroxine (% dose/g tissue; tissue/plasma radioactivity ratio) was investigated in different tissues of 28-week-old obese Wistar rats. Obesity was induced by high-fat diet (HFD) and confirmed by carcass analysis; in heavy obese animals the relative and absolute fat content is increased twofold and threefold, respectively, compared to control rats fed on a low-fat diet (LFD). Heavy HFD rats exhibit diminished /sup 125/I-T/sub 4/ distribution in the 'slow pool' (fat tissue, muscle) and unchanged values in the 'fast pool' (liver, kidneys) in comparison with LFD rats with low body weight. The differences in distribution presented here are not caused by the diet per se, but they are the consequence of the obesity of the animal, because no differences in the /sup 125/I-T/sub 4/ distribution were found in the /sup 125/I-T/sub 4/ between HFD and LFD rats with relatively equal body weight and body composition. The reduced T/sub 4/ distribution in the fat tissue of obese rats is discussed in connection with possibly decreased lipolysis in this tissue and possible causal participation in the beginning of obesity.

Prolactin, cortisol and thyroxine levels and the premature infant

African Journals Online (AJOL)

1983-04-16

Apr 16, 1983 ... and the premature infant ... values in cord and maternal plasma to fetal age and weight and to the incidence of hyaline membrane disease (HMD) was .... thyroxine and prolactin values with an increase in weight has also.

Comparative effectiveness of carvedilol and propranolol on glycemic control and insulin resistance associated with L-thyroxin-induced hyperthyroidism--an experimental study.

Science.gov (United States)

Bhatt, Parloop; Makwana, Dharmesh; Santani, Devdas; Goyal, Ramesh

2007-05-01

The present study was undertaken to investigate the effectiveness of adrenergic antagonists carvedilol and propranolol on L-thyroxin-induced cardiovascular and metabolic disturbances in rats. Treatment with L-thyroxin sodium (75 mg/kg body mass, s.c., every alternate day for 3 weeks), produced a significant increase in food and water intake, body temperature, heart rate, systolic blood pressure, along with an increase in serum T3, T4, and triglyceride levels. Besides a significant reduction in body mass, serum levels of TSH and cholesterol were also reduced following L-thyroxin treatment. Carvedilol (10 mg/kg body mass, orally) and propranolol (10 mg/kg body mass, i.p.) administered daily in the third week to 2 separate groups of L-thyroxin-treated animals reversed thyroxin-induced loss in body mass and rise in body temperature, blood pressure, and heart rate. Propranolol treatment increased TSH levels and decreased T3 and T4 levels in hyperthyroid animals, whereas carvedilol did not produce any effect on thyroid hormones. Carvedilol treatment reversed thyroxin induced hypertriglyceridemia, whereas propranolol treatment had no effect. Both carvedilol and propranolol prevented decrease in cholesterol levels induced by thyroxine. Compared with normal animals, L-thyroxin-treated animals showed a state of hyperglycemia, hyperinsulinaemia, impaired glucose tolerance, and insulin resistance, as inferred from elevated fasting serum glucose and insulin levels, higher area under the curve over 120 min for glucose, and decreased insulin sensitivity index (KITT). Propranolol and carvedilol treatment significantly decreased fasting serum glucose levels. Treatment with propranolol did not alter serum insulin levels, area-under-the-curve glucose, or KITT values. However, treatment with carvedilol significantly reduced area-under-the-curve glucose, decreased fasting serum insulin levels and significantly increased KITT values. In conclusion, carvedilol appears to produce

Importance of the content and localization of tyrosine residues for thyroxine formation within the N-terminal part of human thyroglobulin

NARCIS (Netherlands)

den Hartog, M. T.; Sijmons, C. C.; Bakker, O.; Ris-Stalpers, C.; de Vijlder, J. J.

1995-01-01

Thyroxine (T4) is formed by coupling of iodinated tyrosine residues within thyroglobulin (TG). In mature TG, some iodinated tyrosine residues are involved preferentially in T4 formation. In order to investigate the specific role of various tyrosine residues in T4 formation, N-terminal TG fragments

Evidence for thyroxine transport by the lung and heart capillary endothelium

International Nuclear Information System (INIS)

Heltianu, C.; Dobrila, L.; Antohe, F.; Simionescu, M.

1989-01-01

The uptake and transport of carrier-bound thyroxine by the endothelium were investigated by perfusing through the heart and lung of young rats radiolabeled thyroxine bound to prealbumin ([125I]T4Pa) or serum ([125I]T4S). In addition these complexes were tagged to 5-nm gold particles to obtain quantitative (radioassay) and qualitative (autoradiography) data from the same experiment. The complexes (prewarmed at 37 degrees) were perfused in situ at various concentrations (1 to 50 muCi/ml) for time intervals ranging from 5 to 30 min. After thorough washing of the unbound probe, tissue fragments were either measured for total uptake in a gamma counter or processed for electron microscopy autoradiography. The results showed that both the lung and heart take up [125I]T4 complexes by a process that is saturable at low hormone concentration; uptake is completed by free T4 and Pa. In specimens perfused with double-labeled complexes (iodinated and tagged to gold) autoradiography revealed that silver grains and gold particles colocalize predominantly on endothelial plasmalemmal vesicles. The probe appeared first in vesicles open to the capillary lumen (5 min) and further on in vesicles apparently free within the cytoplasm or open to the abluminal front. At 30 min, only silver grains seem to be present in the pericapillary space, on the alveolar epithelial cells, as well as on the nucleus and mitochondria of heart myocytes. The findings suggest that (1) T4Pa uptake by the endothelial cell (EC) is a specific process (possibly via specific binding sites); (2) T4Pa is taken up and transported across capillary EC by plasmalemmal vesicles; (3) in the pericapillary space T4 seems to dissociate from its carrier

Thyroxin treatment protects against white matter injury in the immature brain via brain-derived neurotrophic factor.

Science.gov (United States)

Hung, Pi-Lien; Huang, Chao-Ching; Huang, Hsiu-Mei; Tu, Dom-Gene; Chang, Ying-Chao

2013-08-01

Low level of thyroid hormone is a strong independent risk factor for white matter (WM) injury, a major cause of cerebral palsy, in preterm infants. Thyroxin upregulates brain-derived neurotrophic factor during development. We hypothesized that thyroxin protected against preoligodendrocyte apoptosis and WM injury in the immature brain via upregulation of brain-derived neurotrophic factor. Postpartum (P) day-7 male rat pups were exposed to hypoxic ischemia (HI) and intraperitoneally injected with thyroxin (T4; 0.2 mg/kg or 1 mg/kg) or normal saline immediately after HI at P9 and P11. WM damage was analyzed for myelin formation, axonal injury, astrogliosis, and preoligodendrocyte apoptosis. Neurotrophic factor expression was assessed by real-time polymerase chain reaction and immunohistochemistry. Neuromotor functions were measured using open-field locomotion (P11 and P21), inclined plane climbing (P11), and beam walking (P21). Intracerebroventricular injection of TrkB-Fc or systemic administration of 7,8-dihydroxyflavone was performed. On P11, the HI group had significantly lower blood T4 levels than the controls. The HI group showed ventriculomegaly and marked reduction of myelin basic protein immunoreactivities in the WM. T4 (1 mg/kg) treatment after HI markedly attenuated axonal injury, astrocytosis, and microgliosis, and increased preoligodendrocyte survival. In addition, T4 treatment significantly increased myelination and selectively upregulated brain-derived neurotrophic factor expression in the WM, and improved neuromotor deficits after HI. The protective effect of T4 on WM myelination and neuromotor performance after HI was significantly attenuated by TrkB-Fc. Systemic 7,8-dihydroxyflavone treatment ameliorated hypomyelination after HI injury. T4 protects against WM injury at both pathological and functional levels via upregulation of brain-derived neurotrophic factor-TrkB signaling in the immature brain.

Production and use of thyroxine antisera in radioimmunoassay technique

International Nuclear Information System (INIS)

Abbas, Sumaia Hussein

2000-06-01

This study describes the production of antisera from sheep and its use in the determination of thyroxine hormone (T 4 ) level in serum using radioimmunoassay (RIA) technique. In this study two local sheep (Ovis aris) were subjected to immunization against human T 4 immunogen, sera obtained from both sheep after each injection were subjected to evaluation through titration in a purified and non purified form. The produced antibodies were used to assemble a kit for the determination of total human serum thyroxine. Different separation techniques were tried, (second antibody polyethylene glycol (PEG) assisted precipitation, polystyrene beads and magnetisable particles solid phases). For the PEG assisted precipitation, local antiserum and that produced by the North East Thamus Region Immunoassay (NETRIA donkey anti-sheep serum (DASS) as second antibodies) were tried. The final dilutions of the anti-T 4 antibody used were 1/4000 in a liquid phase using second antibody PEG assisted separation, 1/3000 using magnetizable particles and a dilution of 1/10,000 using polystyrene beads solid phase for separation. Optimization of T 4 assay conditions including incubation temperature and reaction time were done. Tests for T 4 assay validation (linearity, recovery and responsibility) were carried out. For linearity and recovery tests, the regression coefficient ranges were found to be from (0.8 to 0.9) and (0.88 to 0.98) respectively. The assay was found to be reproducible where the coefficients of variation within and between assays were less than 10%. The locally developed assay was found to be comparable with NETRIA assay as a reference method with a correlation coefficient of 0.88, 0.93 and 0.87 for PEG assisted separation, magnetizable particles and polystyrene beads techniques respectively. The clinical validation tests showed a reliable sensitivity, specificity and efficiency with values of 97%, 94% and 96% respectively. When the T 4 concentrations measured using the

Triiodothyronine and thyroxine content of desiccated thyroid tablets.

Science.gov (United States)

Rees-Jones, R W; Larsen, P R

1977-11-01

Triiodothyronine (T3) and thyroxine (T4) were measured by radioimmunoassay in Pronase hydrolysates of four lots each of 1- and 2-grain tablets of desiccated thyroid (Thyroid, Armour) and thyroglobulin (Proloid, Warner-Chilcott). The methodology used was verified by studies of tablets containing known quantities of T4 and T3. One grain of desiccated thyroid contained 12 +/- 1 and 64 +/- 3 microgram (mean +/- SD) of T3 and T4 per tablet, respectively (T4/T3 molar ratio, 4.3). A 1-grain tablet of thyroglobulin contained 16 +/- 2 and 55 +/- 5 microgram of T3 and T4, respectively with a T4/T3 ratio of 2.9. Two-grain tablets generally contained twice the quantity of T3 and T4 in the 1-grain preparations. The variation in T3 and T4 content between the four lots of each tablet strength for each product was 10% or less. These estimates of T3 and T4 content are 1.5- to 2-fold greater than those previously published. This difference probably results from the more sophisticated methodology now available which does not require chromatographic separation of T3 and T4 or iodometry. Using calculations based on published estimates of T4 and T3 absorption and of the T3/T4 potency ratio, it would appear that the T3 content of desiccated thyroid and thyroglobulin provide approximately 39% and 51%, respectively, of the thyromimetic activity of these two medications.

Effect of thyroxine on brain microstructure in extremely premature babies: magnetic resonance imaging findings in the TIPIT study.

Science.gov (United States)

Ng, Sze May; Turner, Mark A; Gamble, Carrol; Didi, Mohammed; Victor, Suresh; Atkinson, Jessica; Sluming, Vanessa; Parkes, Laura M; Tietze, Anna; Abernethy, Laurence J; Weindling, Alan Michael

2014-08-01

In order to assess relationships between thyroid hormone status and findings on brain MRI, a subset of babies was recruited to a multi-centre randomised, placebo-controlled trial of levothyroxine (LT4) supplementation for babies born before 28 weeks' gestation (known as the TIPIT study, for Thyroxine supplementation In Preterm InfanTs). These infants were imaged at term-equivalence. Forty-five TIPIT participants had brain MRI using diffusion tensor imaging (DTI) to estimate white matter development by apparent diffusion coefficient (ADC), fractional anisotropy (FA) and tractography metrics of number and length of streamlines. We made comparisons between babies with the lowest and highest plasma FT4 concentrations during the initial 4 weeks after birth. There were no differences in DTI metrics between babies who had received LT4 supplementation and those who had received a placebo. Among recipients of a placebo, babies in the lowest quartile of plasma-free thyroxine (FT4) concentrations had significantly higher apparent diffusion coefficient measurements in the posterior corpus callosum and streamlines that were shorter and less numerous in the right internal capsule. Among LT4-supplemented babies, those who had plasma FT4 concentrations in the highest quartile had significantly lower apparent diffusion coefficient values in the left occipital lobe, higher fractional anisotropy in the anterior corpus callosum and longer and more numerous streamlines in the anterior corpus callosum. DTI variables were not associated with allocation of placebo or thyroid supplementation. Markers of poorly organised brain microstructure were associated with low plasma FT4 concentrations after birth. The findings suggest that plasma FT4 concentrations affect brain development in very immature infants and that the effect of LT4 supplementation for immature babies with low FT4 plasma concentrations warrants further study.

Thyroxine and triiodothyronine kinetics in aging subjects

International Nuclear Information System (INIS)

Degrossi, O.J.; Carneiro, L.; Scornavachi, J.C.; Cima, M.E.; Mollerach, F.E.; Almeida, C.A.; Casas, O.I. de; Diez, F.

1980-06-01

Age modifications on serum levels of thyrotropin hormone (TSH) thyroxine (T4) and Triiodothyronine (T3), as well the kinetics of T4 and T3 were studied. T4 serum values were found to be in the normal range. T3 rates showed a significant decrease as TSH showed a slight increase, which was only significantin patients over 70 year-old. Metabolic T4 turnover allowed to observe a slower T4 disappearance rate with dialy degradation values of 35,4 μg/day/m 2 +-14,1 (S.D.)as compared with those of the control subjects (49,0+-14,6): Distribution space was in the normal range. On the contrary, for T3 a sharp decrease in distribution space (31,1% body weight+-3,5; controls 58,8%+-7,6), a slight lengthening in disappearance rate and a marked shortening of the clearance (17,32 l/d+-6,20; controls 33,72+-8.55), of T3 extrathyroid pool (14,5 μg+-1,8; controls 45,7+-4.7) and of the daily degradation rate (4,3 μg/d/m 2 +-1,7; controls: 15,3+-2,6) were observed. These results conveys to considere a diminished thyroid hormones production and of an also diminished peripheric conversion of T4 to T3. It should be delucidated if there is a real inadequate thyroid hormones suply to the tissues or if there is only an adaptation, to lower demands due to a diminished functional mass [es

Determination of the percentage of the /sup 125/I-lyothyronine retention in resin (T/sub 3/ Test) and the total tyroxin (T/sub 4/ Test) in mongrel equines

Energy Technology Data Exchange (ETDEWEB)

Iwasaki, M [Sao Paulo Univ. (Brazil). Faculdade de Medicina Veterinaria e Zootecnia

1975-01-01

Thyroid function is studied in mongrel equines by means of radioisotopic techniques 'in vitro' /sup 125/I-T/sub 3/ (/sup 125/I-lyothyronine retention in resin) and /sup 125/I-T/sub 4/ (total thyroxine).

In vitro diagnosis of T3-thyrotoxicosis

International Nuclear Information System (INIS)

Semenov, V.D.

1983-01-01

A study was made of the importance of various radioimmunoassays and their reliability in the diagnosis of functional activity of the thyroid parenchyma in patients with nodular goiter. To define the effect of the globulin thyroxine binding ability on the level of general serum triiodothyronine (T 3 ), the index of triiodothyronine and the index of elevated serum triiodothyronine (IEST 3 ) were calculated. A comprehensive procedure of test registration reflecting hypophyseal-thyroid function was used to reveal 3 types of thyrotoxicoses: Tsub(3/4)-thyrotoxicosis, T 3 -thyrotoxicosis and T 4 -thyrotoxicosis. A high informative value of the main tests - the determination of the content of general thyroxine (T 4 ), T 3 and effective thyroxine factor - was established. The IEST 3 is of the utmost diagnostic value, particularly in diagnosing T 3 -thyrotoxicosis

The effect of thyroxine on silk gland and the effect of two thyroxine ...

African Journals Online (AJOL)

The influence of feeding mulberry leaves treated with thyroxine to the growth of the silk gland, and the effect of two different mulberry species, that is, Morus nigra and Morus multicaulis treated with thyroxine on silk quality in the silkworm were studied. The silk glands from thyroxine treated Bombyx mori larvae weighed ...

Propranolol inhibits the in vitro conversion of thyroxine into triiodothyronine by isolated rat liver parenchymal cells

NARCIS (Netherlands)

van Noorden, C. J.; Wiersinga, W. M.; Touber, J. L.

1979-01-01

A model for the in vitro study of the conversion of thyroxine into triiodothyronine using isolated rat liver parenchymal cells is described. Isolated liver cells (mean protein content 18 mg/ml) convert approximately 0.8% of 1.3 microM exogenously added T4 into T3 during thirty minutes incubation.

Radioimmunoassay method for triiodothyronine and thyroxine

International Nuclear Information System (INIS)

Hollander, C.S.

1975-01-01

This invention relates to a radioimmunoassay method for triiodothyronine or thyroxine or triiodothyronine and thyroxine present in unextracted serum containing thyroxine binding prealbumin and thyroxine binding globulin. Procedures using 125 I and 131 I are described

Unusual ratio between free thyroxine and free triiodothyronine in a long-lived mole-rat species with bimodal ageing.

Directory of Open Access Journals (Sweden)

Yoshiyuki Henning

Full Text Available Ansell's mole-rats (Fukomys anselli are subterranean, long-lived rodents, which live in eusocial families, where the maximum lifespan of breeders is twice as long as that of non-breeders. Their metabolic rate is significantly lower than expected based on allometry, and their retinae show a high density of S-cone opsins. Both features may indicate naturally low thyroid hormone levels. In the present study, we sequenced several major components of the thyroid hormone pathways and analyzed free and total thyroxine and triiodothyronine in serum samples of breeding and non-breeding F. anselli to examine whether a their thyroid hormone system shows any peculiarities on the genetic level, b these animals have lower hormone levels compared to euthyroid rodents (rats and guinea pigs, and c reproductive status, lifespan and free hormone levels are correlated. Genetic analyses confirmed that Ansell's mole-rats have a conserved thyroid hormone system as known from other mammalian species. Interspecific comparisons revealed that free thyroxine levels of F. anselli were about ten times lower than of guinea pigs and rats, whereas the free triiodothyronine levels, the main biologically active form, did not differ significantly amongst species. The resulting fT4:fT3 ratio is unusual for a mammal and potentially represents a case of natural hypothyroxinemia. Comparisons with total thyroxine levels suggest that mole-rats seem to possess two distinct mechanisms that work hand in hand to downregulate fT4 levels reliably. We could not find any correlation between free hormone levels and reproductive status, gender or weight. Free thyroxine may slightly increase with age, based on sub-significant evidence. Hence, thyroid hormones do not seem to explain the different ageing rates of breeders and non-breeders. Further research is required to investigate the regulatory mechanisms responsible for the unusual proportion of free thyroxine and free triiodothyronine.

Unusual ratio between free thyroxine and free triiodothyronine in a long-lived mole-rat species with bimodal ageing.

Science.gov (United States)

Henning, Yoshiyuki; Vole, Christiane; Begall, Sabine; Bens, Martin; Broecker-Preuss, Martina; Sahm, Arne; Szafranski, Karol; Burda, Hynek; Dammann, Philip

2014-01-01

Ansell's mole-rats (Fukomys anselli) are subterranean, long-lived rodents, which live in eusocial families, where the maximum lifespan of breeders is twice as long as that of non-breeders. Their metabolic rate is significantly lower than expected based on allometry, and their retinae show a high density of S-cone opsins. Both features may indicate naturally low thyroid hormone levels. In the present study, we sequenced several major components of the thyroid hormone pathways and analyzed free and total thyroxine and triiodothyronine in serum samples of breeding and non-breeding F. anselli to examine whether a) their thyroid hormone system shows any peculiarities on the genetic level, b) these animals have lower hormone levels compared to euthyroid rodents (rats and guinea pigs), and c) reproductive status, lifespan and free hormone levels are correlated. Genetic analyses confirmed that Ansell's mole-rats have a conserved thyroid hormone system as known from other mammalian species. Interspecific comparisons revealed that free thyroxine levels of F. anselli were about ten times lower than of guinea pigs and rats, whereas the free triiodothyronine levels, the main biologically active form, did not differ significantly amongst species. The resulting fT4:fT3 ratio is unusual for a mammal and potentially represents a case of natural hypothyroxinemia. Comparisons with total thyroxine levels suggest that mole-rats seem to possess two distinct mechanisms that work hand in hand to downregulate fT4 levels reliably. We could not find any correlation between free hormone levels and reproductive status, gender or weight. Free thyroxine may slightly increase with age, based on sub-significant evidence. Hence, thyroid hormones do not seem to explain the different ageing rates of breeders and non-breeders. Further research is required to investigate the regulatory mechanisms responsible for the unusual proportion of free thyroxine and free triiodothyronine.

Effect of thyroidectomy and thyroxine on 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced immunotoxicity

International Nuclear Information System (INIS)

Pazdernik, T.L.; Rozman, K.K.

1985-01-01

Radiothyroidectomy protected against 2,3,7,8-tetrachloro dibenzo-p-dioxin (TCDD)-induced immunotoxicity in rats as assessed by the spleen anti-SRBC plaque-forming cell assay. Thyroxin (T 4 ) replacement therapy partially reversed the effects of thyroidectomy on T 4 and triiodothyronine (T 3 ) serum levels, body weight and immune function as well as restored TCDD-induced immunotoxicity. Thus, hypothyroidism induced by TCDD exposure can be viewed as a protective response of the organism to reduce the insult caused by TCDD

Circadian variations of serum thyrotropin, thyroxine, triiodothyronine, reverse triiodothyronine, corticosterone and lipids in starved rats

International Nuclear Information System (INIS)

Zwirska-Korczala, K.; Ostrowska, Z.; Kucharzewski, M.; Marek, B.; Kos-Kudla, B.; Buntner, B.; Swietochowska, E.

1993-01-01

We investigated the circadian variation of serum thyrotropin (TSH), thyroxine (T 4 ), triiodothyronine (T 3 ), reverse triiodothyronine (rT 3 ), corticosterone (B) and lipids in male Wistar rats after one-week starvation. Starvation decreased the TSH level and eliminated its 24-h rhythm. The rhythmicity of oscillations of T 3 and B was maintained. Starvation led to a shift in the acrophase of 24-h T 3 and B oscillation and induced the circadian rhythm of T 4 . The T 3 , T 4 and mesor values were lower, while for rT 3 and B they increased. Lipid concentrations remained unchanged in both experimental and control rats. (author). 27 refs, 3 figs, 2 tabs

An improved method for the radioimmunoassay of free-thyroxine in serum dialysates

International Nuclear Information System (INIS)

Giles, A.F.

1982-01-01

A convenient, sensitive radioimmunoassay (using 125 I) of free thyroxine in serum dialysates is described. The method utilizes a solid phase separation system (pre-formed double antibody) and a relatively short incubation period (220 min) with a staggered addition of tracer. Blanks were low and consistent. The normal range for non-pregnant euthyroid samples (n = 59) was 11-23 pmol/l. Third trimester pregnancy samples were mostly within the normal range but at the lower end. Patients on T4 replacement showed a much wider variation in free T4 levels with many samples in the hyperthyroid region. Some hypothyroid samples had undetectable free T4 levels and hyperthyroid samples were frequently greater than 80 pmol/l. (author)

Prolactin, cortisol and thyroxine levels and the premature infant ...

African Journals Online (AJOL)

The relationship of prolactin, cortisol and thyroxine values in cord and maternal plasma to fetal age and weight and to the incidence of hyaline membrane disease (HMD) was investigated in 80 neonates of whom 40 were born at more than 37 weeks' gestation. Of the 40 born at less than 36 weeks 11 developed HMD.

Interlaboratory survey for T3 and T4 assays in Italy: results from a two semester period

International Nuclear Information System (INIS)

Pilo, A.; Zucchelli, G.C.; Chiesa, M.R.; Piro, M.A.

1982-01-01

The usefulness of external quality control schemes (EQCS) is generally acknowledged in clinical chemistry; these schemes allow not only the evaluation of the between-laboratory variability of the assay under study, but also make it possible the improvement of the analytical performances of the participants laboratories. Recently interlaboratory surveys have been extended to radioimmunoassays. Starting from january 1980, a national EQCS hormone assays was organized in Italy; triiodothyronine (T3) and thyroxine (T4) have been the first assays considered due to their large diffusion

Total and free thyroxine and triiodothyronine: measurement discrepancies, particularly in inpatients.

Science.gov (United States)

Jonklaas, Jacqueline; Sathasivam, Anpalakan; Wang, Hong; Gu, Jianghong; Burman, Kenneth D; Soldin, Steven J

2014-09-01

We compared the performance of tandem mass spectrometry versus immunoassay for measuring thyroid hormones in a diverse group of inpatients and outpatients. Thyroxine (T4), triiodothyronine (T3), free thyroxine (FT4), and free triiodothyronine (FT3) were measured by liquid chromatography tandem mass spectrometry and immunoassay in 100 patients and the two assays were compared. T4 and T3 values measured by the two different assays correlated well with each other (r=0.91-0.95). However, the correlation was less good at the extremes (r=0.51-0.75). FT4 and FT3 concentrations measured by the two assays correlated less well with each other (r=0.75 and 0.50 respectively). The studied analytes had poor inverse correlation with the log-transformed TSH values (r=-0.22-0.51) in the population as a whole. The strongest correlations were seen in the groups of outpatients (r=-0.25-0.61). The weakest degree of correlation was noted in the inpatient group, with many correlations actually being positive. The worst between-assay correlation was demonstrated at low and high hormone concentrations, in the very concentration ranges where accurate assay performance is typically most clinically important. Based on the lesser susceptibility of mass spectrometry to interferences from conditions such as binding protein abnormalities, we speculate that mass spectrometry better reflects the clinical situation. In this mixed population of inpatients and outpatients, we also note failure of assays to conform to the anticipated inverse linear relationship between thyroid hormones and log-transformed TSH. Copyright © 2014 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Influence of adsorption and deproteination on potential free thyroxine reference methods

DEFF Research Database (Denmark)

Holm, Steen S; Andreasen, Lisbeth; Hansen, Palle Steen

2002-01-01

There is a need for consensus concerning reference methods to be used for calibration of commercial free-thyroxine (FT(4)) assays.......There is a need for consensus concerning reference methods to be used for calibration of commercial free-thyroxine (FT(4)) assays....

The influence of thyroxine and propyl thiouracil on Parastrongylus malaysiensis infection in rats.

Science.gov (United States)

Kamis, A B; Ahmad, R A; Chang, J S; Ambu, S

1994-01-01

Daily intramuscular injection with thyroxine (T4) at a dose of 2.5 micrograms/100 g body weight decreased the larvae and adult worm burden of Parastrongylus malaysiensis in the brain and pulmonary arteries of male Sprague-Dawley albino rats. In contrast, rats treated with propyl thiouracil (PTU), an antithyroid drug, at a dose of 3.75 mg/100 g body weight retained greater numbers of larvae and adult worms. The results may reflect the contrasting immunomodulatory effects of T4 and PTU that influence the susceptibility of the host.

Thyroxine transport in choroid plexus

International Nuclear Information System (INIS)

Dickson, P.W.; Aldred, A.R.; Menting, J.G.; Marley, P.D.; Sawyer, W.H.; Schreiber, G.

1987-01-01

The role of the choroid plexus in thyroid hormone transport between body and brain, suggested by strong synthesis and secretion of transthyretin in this tissue, was investigated in in vitro and in vivo systems. Rat choroid plexus pieces incubated in vitro were found to accumulate thyroid hormones from surrounding medium in a non-saturable process. At equilibrium, the ratio of thyroid hormone concentration in choroid plexus pieces to that in medium decreased upon increasing the concentration of transthyretin in the medium. Fluorescence quenching of fluorophores located at different depths in liposome membranes showed maximal hormone accumulation in the middle of the phospholipid bilayer. Partition coefficients of thyroxine and triiodothyronine between lipid and aqueous phase were about 20,000. After intravenous injection of 125 I-labeled thyroid hormones, choroid plexus and parts of the brain steadily accumulated 125 I-thyroxine, but not [ 125 I]triiodothyronine, for many hours. The accumulation of 125 I-thyroxine in choroid plexus preceded that in brain. The amount of 125 I-thyroxine in non-brain tissues and the [ 125 I]triiodothyronine content of all tissues decreased steadily beginning immediately after injection. A model is proposed for thyroxine transport from the bloodstream into cerebrospinal fluid based on partitioning of thyroxine between choroid plexus and surrounding fluids and binding of thyroxine to transthyretin newly synthesized and secreted by choroid plexus

The concentration of iodine in horse serum and its relationship with thyroxin concentration by geological difference.

Science.gov (United States)

Mochizuki, Mariko; Hayakawa, Noriyuki; Minowa, Fumiko; Saito, Akihiro; Ishioka, Katsumi; Ueda, Fukiko; Okubo, Kimihiro; Tazaki, Hiroyuki

2016-04-01

In this study, iodine and thyroxin (T4) concentrations in the serum of 69 horses were investigated. Higher iodine concentrations were obtained from the horses housed in Chiba Prefecture. In contrast, T4 concentrations of horses at Shizuoka Prefecture were higher than those of horses at Chiba Prefecture. There was a significant correlation (r = 0.643, P geological differences. It was thought that equine serum is a useful sample for monitoring.

Control survey of normal reference ranges adopted for serum thyroxine binding globulin, thyroxine, triiodothyronine in Japan

International Nuclear Information System (INIS)

Sugisaki, Hajime; Kameyama, Mayumi; Shibata, Kyoko

1985-01-01

A survey using questionnaires was made on 152 facilities from July through September 1984 to examine normal reference ranges of serum thyroxine binding globulin (TBG), thyroxine (TT 4 ), and triiodothyronine (TT 3 ). Normal reference ranges of TBG were in good agreement with each other, with the exception of four facilities showing high upper limits. An average value of the upper and lower limits in 83 facilities was 13.7 +- 1.9 μg/ml; and the standard deviation was 28.6 +- 2.8 μg/ml. Differences (approximately 10 %) in coefficient of variation were comparable to those (5.7-9.6 %) obtained from the previous survey. There were approximately 10 % differences in coefficient of variation for both TT 4 and TT 3 . (Namekawa, K.)

Thyroxine clearance in rats within the first month after the single whole-body {gamma} - irradiation at a dose of 10Gy

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Pryadko, Kirill A. [Institute of Radiobiology, National Academy of Sciences, Minsk (Belarus)

2002-07-01

The effects of acute whole-body {gamma} -irradiation at a dose of 10 Gy on thyroxine (T{sub 4}) plasma clearance rate (PCR) and thyroidal and blood T4 concentration ([T{sub 4}]) were examined within one month after exposure. The PCR values were measured using the bolus injection, single-compartmental approach. To eliminate the influence of radiation-induced anorexia animals were fasting for two days before the pharmacokinetic experiments. Hormone concentrations in blood and in thyroid tissue were measured by RIA. Throughout the observation period, PCR was elevated in irradiated rats with maximum at day 4 after exposure (0.56{+-}0.04 vs. 0.36{+-}0.03 ml/h100 gbw, P<0.001). [T{sub 4}] in blood was not significantly different from that in control animals. Thyroidal [T{sub 4}] was significantly decreased in irradiated animals 4 days after exposure (151.8{+-}21.7 vs. 258.8{+-}29.9 pmol/mg protein, P<0.01) and gradually increased after day 9. 10 Gy {gamma} -irradiation causes the intensification of T{sub 4} metabolism without the pronounced changes in concentration. Presumably, at early terms the rising local demand in O{sub 4} can not be compensated with the existing level of production. Alterations in the intensity of T{sub 4} metabolism are evident at least one month after exposure but they may not be detected without taking into account kinetic data.

Recovery following Thyroxine Treatment Withdrawal, but Not Propylthiouracil, Averts In Vivo and Ex Vivo Thyroxine-Provoked Cardiac Complications in Adult FVB/N Mice

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Nancy S. Saad

2017-01-01

Full Text Available Persistent cardiovascular pathology has been described in hyperthyroid patients even with effective antithyroid treatment. Here, we studied the effect of a well-known antithyroid drug, propylthiouracil (PTU; 20 mg/kg/day, on thyroxine (T4; 500 µg/kg/day-induced increase in blood pressure (BP, cardiac hypertrophy, and altered responses of the contractile myocardium both in vivo and ex vivo after 2 weeks of treatment. Furthermore, the potential recovery through 2 weeks of T4 treatment discontinuation was also investigated. PTU and T4 recovery partially reduced the T4-prompted increase in BP. Alternatively, PTU significantly improved the in vivo left ventricular (LV function with no considerable effects on cardiac hypertrophy or ex vivo right ventricular (RV contractile alterations subsequent to T4 treatment. Conversely, T4 recovery considerably enhanced the T4-provoked cardiac changes both in vivo and ex vivo. Altogether, our data is in agreement with the proposal that hyperthyroidism-induced cardiovascular pathology could persevere even with antithyroid treatments, such as PTU. However, this cannot be generalized and further investigation with different antithyroid treatments should be executed. Moreover, we reveal that recovery following experimental hyperthyroidism could potentially ameliorate cardiac function and decrease the risk for additional cardiac complications, yet, this appears to be model-dependent and should be cautiously construed.

[Combined l-thyroxine and l-triiodothyronine replacement therapy in congenital hypothyroidism].

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Péter, Ferenc; Muzsnai, Agota

2013-05-12

L-thyroxine replacement therapy is the treatment of choice for hypothyroidism. Recently, several studies suggested to complete it with l-triiodothyronine in acquired hypothyroidism. To study the role of combined l-thyroxine and l-triiodothyronine therapy in special cases with congenital hypothyroidism. Data of 16 patients (age: 11.9 ± 6.3 years; mean ± SD) are presented who had high serum free thyroxine values or even above the upper limit of reference range (21.16 ± 2.5 pmol/l) together with nonsuppressed TSH levels (15.7 ± 5.7 mIU/l), and therefore received l-triiodothyronine in completion (0.18 ± 0.09 μg/kg) once a day. The combined replacement therapy resulted in a rapid improvement of the hormone parameters (TSH: 4.2 ± 3.15 mIU/l; free thyroxine: 16.55 ± 2.4 and free triiodothyronine: 7.4 ± 1.8 pmol/l). The efficiency of this combined therapy proved to be more evident (TSH: 4.33 ± 3.2 mIU/l; free thyroxine: 16.85 ± 3.1 and free triiodothyronine: 6.4 ± 0.85 pmol/l) in 10 patients treated for a longer period of time (duration of treatment: 2.9 ± 2.0 years). The dose of thyroxine substitution decreased from 2.6 ± 0.9 to 2.18 ± 0.6 μg/kg/day), the ratio of these hormones was between 5:1 and 19:1 and the quotient of free fractions was normalized (3.8 ± 0.4→2.6 ± 0.3) during the replacement therapy. According to the observation of the authors a serious disturbance of feed-back mechanism may develop in some (>5%) children with congenital hypothyroidism (increased TSH release despite elevated free thyroxine level) after normal function of the feed-back system for years. Hormone parameters of these patients improve, then become normal on combined therapy supporting the rationale for this treatment method.

Triclosan exposure reduces thyroxine levels in pregnant and lactating rat dams and in directly exposed offspring

DEFF Research Database (Denmark)

Petersen, Marta Axelstad; Boberg, Julie; Vinggaard, Anne Marie

2013-01-01

Thyroid disrupting chemicals can potentially disrupt brain development. Two studies investigating the effect of the antibacterial compound triclosan on thyroxine (T4) levels in rats are reported. In the first, Wistar rat dams were gavaged with 75, 150 or 300 mg triclosan/kg bw/day throughout gest...

The t-SNAREs syntaxin4 and SNAP23 but not v-SNARE VAMP2 are indispensable to tether GLUT4 vesicles at the plasma membrane in adipocyte

International Nuclear Information System (INIS)

Kawaguchi, Takayuki; Tamori, Yoshikazu; Kanda, Hajime; Yoshikawa, Mari; Tateya, Sanshiro; Nishino, Naonobu; Kasuga, Masato

2010-01-01

SNARE proteins (VAMP2, syntaxin4, and SNAP23) have been thought to play a key role in GLUT4 trafficking by mediating the tethering, docking and subsequent fusion of GLUT4-containing vesicles with the plasma membrane. The precise functions of these proteins have remained elusive, however. We have now shown that depletion of the vesicle SNARE (v-SNARE) VAMP2 by RNA interference in 3T3-L1 adipocytes inhibited the fusion of GLUT4 vesicles with the plasma membrane but did not affect tethering of the vesicles to the membrane. In contrast, depletion of the target SNAREs (t-SNAREs) syntaxin4 or SNAP23 resulted in impairment of GLUT4 vesicle tethering to the plasma membrane. Our results indicate that the t-SNAREs syntaxin4 and SNAP23 are indispensable for the tethering of GLUT4 vesicles to the plasma membrane, whereas the v-SNARE VAMP2 is not required for this step but is essential for the subsequent fusion event.

Radioimmunoassay of serum T3, T4 and TSH during anesthesia and operation

International Nuclear Information System (INIS)

Gosheva-Antonova, Ts.; Zakharieva, B.; Kurtev, I.

1987-01-01

The serum concentrations of thyroxine (T 3 ), triiodothyronine (T 4 ) and thyroid-stimulating hormone (TSH) were determined in 31 partients before and during urologic operations on the 30th and 60th minute since the onset of the operation, performed under endotracheal halotane or neuroleptanesthesia (NLA) in assisted breathing and intravenous drip anesthesia with ketalar-diazepam in spontaneous breathing. There was statistically significant rise in T 4 level, decrease in T 3 and negligible changes in TSH level, in patients operated under halotane anesthesia. In those operated under NLA, T 4 tended initially to be elevated, with subseguent fall to starting level, with a tendency toward rise in TSH and stable unchanged T 3 level. Ketalar-diazepam anesthesia was applied only to patients subjected to transurethral resections. T 4 in them tended to be decreased, while T 3 and TSH showed negligible changes. Since the operations of patients anesthesized with halotane and NLA had similar localizations and severity, the differences in the thyroid hormone reactions could be associated with the type of anesthesia. The negligible changes in TSH are highly suggestive that this hormone is not influenced by the operation stress and anesthetics, and does hot exert regulating effect upon the thyroid status under these conditions. The milder reactions in patients operated under ketalar-diazepam anestesia may largely be associated with the milder operation stress in transurethal resection

Polybrominated diphenyl ethers--plasma levels and thyroid status of workers at an electronic recycling facility.

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Julander, A; Karlsson, M; Hagström, K; Ohlson, C G; Engwall, M; Bryngelsson, I-L; Westberg, H; van Bavel, B

2005-08-01

Personnel working with electronic dismantling are exposed to polybrominated diphenyl ethers (PBDEs), which in animal studies have been shown to alter thyroid homeostasis. The aim of this longitudinal study was to measure plasma level of PBDEs in workers at an electronic recycling facility and to relate these to the workers' thyroid status. PBDEs and three thyroid hormones: triiodothyronine (T(3)), thyroxin (T(4)) and thyroid stimulating hormone (TSH) were repeatedly analysed in plasma from 11 workers during a period of 1.5 years. Plasma levels of PBDEs at start of employment were plasma levels of PBDEs fluctuated during the study period. Due to small changes in thyroid hormone levels it was concluded that no relevant changes were present in relation to PBDE exposure within the workers participating in this study.

Conversion of L-thyroxine to L-triiodothyronine in the rat liver under in vitro conditions

International Nuclear Information System (INIS)

Nauman, A.; Kaminski, T.; Pastuszko, D.

1979-01-01

Conversion of thyroxine (T 4 ) to triiodothyronine (T 3 ) has been studied in liver homogenates obtained from normal and hypothyroid rats. Liver homogenates were incubated for 0-60 minutes at 37 0 C in Tris buffer containing sucrose and T 4 , pH 7.4. T 3 generated during incubation was measured by a specific radioimmunoassay of an ethanol extract of the incubates. Conversion rate of T 4 to T 3 by liver homogenates from intact rats was found to be time, protein concentration and substrate concentration (T 4 ) dependent. Heating of homogenate above 60 0 C abolished while cooling significantly decreased the monodeiodination. In homogenates from hypothyroid rats the conversion and its rate were significantly decreased. The results of present study confirmed enzymatic character of monodeiodination reaction. Decreased conversion of T 4 to T 3 in hypothyroidism suggests that biosynthesis of converting enzyme may be regulated by thyroid hormones. (author)

Endothelial Functioning and Hemodynamic Parameters in Rats with Subclinical Hypothyroid and the Effects of Thyroxine Replacement.

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Cuixia Gao

Full Text Available Subclinical hypothyroidism (SCH and its associations with atherosclerosis (AS and cardiovascular disease remain controversial. The purpose of our study was to observe changes in endothelial functioning and hemodynamics in rats with SCH and to determine whether L-thyroxine (L-T4 administration affects these changes.In total, sixty male Wistar rats were randomly divided into the following three groups with 20 rats each: control euthyroid rats, SCH rats and SCH rats that had been treated with thyroxine (SCH+T4. The SCH rats were induced by administration of 10 mg x kg(-1 x d(-1 methimazole (MMI once daily by gavage for 3 months. The SCH+T4 rats were administered the same dose of MMI for three months in addition to 2 μg x kg(-1 x d(-1 L-T4 once daily by gavage after 45 days of MMI administration. The control rats received physiological saline via gavage.The SCH group had significantly higher thyroid-stimulating hormone (TSH, total cholesterol (TC, low-density lipoprotein cholesterol (LDL-C, and endothelin (ET levels and a lower nitric oxide (NO level than the control and SCH+T4 groups. The tail and carotid artery blood pressures, left ventricular systolic pressure, heart rate and aorta ventralis blood flow were significantly lower in the SCH group than in the control and SCH+T4 groups. ACH treatment caused concentration-dependent relaxation, which was reduced in the SCH arteries compared with the control and SCH+T4 arteries. Histopathological examination revealed the absence of pathological changes in the SCH rat arteries.These findings demonstrate that L-T4 treatment ameliorates endothelial dysfunction and hemodynamic changes in SCH rats.

A simple ligand-binding assay for thyroxine-binding globulin on reusable Sephadex columns

International Nuclear Information System (INIS)

Bastomsky, C.H.; Kalloo, H.; Frenkel-Leith, D.B.; McGill Univ., Montreal, Quebec

1977-01-01

A method for the assay of thyroxine-binding globulin on reusable Sephadex G-25 columns is described. It depends upon elution by diluted iodothyronine-free serum of protein-bound [ 125 I]thyroxine from the columns under conditions where binding to thyroxine-binding prealbumin and albumin are abolished. It is simple, rapid and precise, and permits determinations inlarge numbers of samples. Values (mg/l; mean +- S.D.) were: normals 31.6+-5.4, hyperthyroid 28.3+-4.8, hypothyroid 40.6+-7.5, oral contraceptives 40.1+-6.8, pregnant 50.3+-5.4, cirrhotics 20.7+-4.3. Concentrations were reduced in serum heated at 56degC, while the uptake of [ 125 I]triiodothyronine was increased. There was a significant negative correlation between thyroxine-binding globulin concentration and triiodothyronine uptake in the heated serum samples and in euthyroid subjects

Effects of shugan jieyu panacea on behavior and levels of ACTH in plasma and T3, T4, TSH and rT3 in serum in depression rats

International Nuclear Information System (INIS)

Li Huijing; Li Yang; Yao Jinghui; Li Youtian

2010-01-01

Objective: To investigate the effects of Shugan Jieyu Panacea (SJP) on behavior and the levels of ACTH in plasma and T 3 , T 4 , TSH, rT 3 in serum in depression model rats and explore the mechanism. Methods: The model rats were lonely fed and received chronic moderate intensive unpredictable stimulation. Normal control group, depressed model group, high dosage SJP group, middle dosage SJP group, low dosage SJP group and fluoxetine group were set up. Different drugs were used in various groups for 21 d, then the body mass, sugar consumption and the behavior changes of the rats were determined and the levels of ACTH in plasma and T 3 , T 4 , TSH, rT 3 in serum were detected with radioimmunoassay. Results: Compared with normal group,the body mass was decreased (P 4 , rT 3 markedly decreased (P 3 was increased (P<0.05) in high, middle, low dosage SJP groups after treatment. At the same time, there was no obvious difference between SJP groups and fluoxetine groups. Conclusion: SJP can significantly improve the depression in rats, its mechanism may be connected with adjusting the function of HPAA and HPTA. (authors)

A novel formulation of L-thyroxine (L-T4) reduces the problem of L-T4 malabsorption by coffee observed with traditional tablet formulations.

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Vita, Roberto; Saraceno, Giovanna; Trimarchi, Francesco; Benvenga, Salvatore

2013-02-01

The purpose of this work is to evaluate if the coffee-associated malabsorption of tablet levothyroxine (L-T4) is reduced by soft gel capsule. We recruited 8 patients with coffee-associated L-T4 malabsorption including one hypothyroid patient. For 6 months, the patients were switched to the capsule maintaining the L-T4 daily dose. Patients took the capsule with water, having coffee 1 h later (proper habit, PH) on days 1-90, or with coffee ≤ 5 min later (improper habit, IH) on days 91-180. After 6 months, 2 patients volunteered for an acute loading test of 600 μg L-T4 (capsule) ingested with water (PH) or with coffee (IH). In the single hypothyroid patient, the post-switch TSH ranged 0.06-0.16 mU/L (PH) versus 5.8-22.4 mU/L pre-switch (PH) and 0.025-0.29 mU/L (IH) versus 26-34 mU/L pre-switch (IH). In the other 7 patients, post-switch TSH was 0.41 ± 0.46 (PH) versus 0.28 ± 0.20 pre-switch (PH) (P = 0.61) and 0.34 ± 0.30 (IH) versus 1.23 ± 1.47 pre-switch (IH) (P coffee influenced L-T4 pharmacokinetics minimally. Soft gel capsules can be used in patients who are unable/unwilling to change their IH of taking L-T4.

Thyroxine (T4) Test

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... K. Brunner & Suddarth's Handbook of Laboratory and Diagnostic Tests. 2 nd Ed, Kindle. Philadelphia: Wolters Kluwer Health, Lippincott Williams & Wilkins; c2014. Thryoxine, Serum 485 p. Lab Tests ...

Analytical Application of Flow Immunosensor in Detection of Thyroxine and Triiodothyronine in Serum.

Science.gov (United States)

Wani, Tanveer A; Zargar, Seema; Majid, Salma; Darwish, Ibrahim A

2016-11-01

In this study, an immunosensor based on kinetic exclusion analysis (KinExA) was used for thyroxine (T4) and triiodothyronine (T3) estimation. A KinExA™ 3200 instrument was used for this analysis, which is an automated flow fluorimeter designed to separate free unbound antibody binding sites in reaction mixtures of antibody, antigen, and antibody-antigen complex. A T3-BSA- and T4-BSA-coated polymethyl methacrylate (PMMA) bead microcolumn is generated inside the flow cell of the instrument. A sample mixture containing T3 and T4 with their respective monoclonal antibodies and their complexes are drawn past the microbead column. The unbound T3 or T4 monoclonal antibody binding sites are captured by their respective T3 and T4 antigens coated on the PMMA beads as bovine serum albumin conjugates. Fluorescently labeled secondary antibodies bind to the T3 or T4 antigen-antibody complex to generate fluorescence intensity for analysis. The limit of detection for the T3 and T4 assays was found to be 0.06 and 1.9 ng mL -1 with acceptable precision values. The convenience of the automated KinExA format may be valuable in medical diagnostic laboratories.

Specific labeling of the thyroxine binding site in thyroxine-binding globulin: determination of the amino acid composition of a labeled peptide fragment isolated from a proteolytic digest of the derivatized protein.

Science.gov (United States)

Tabachnick, M; Perret, V

1987-08-01

[125I] Thyroxine has been covalently bound to the thyroxine binding site in thyroxine-binding globulin by reaction with the bifunctional reagent, 1,5-difluoro-2,4-dinitrobenzene. An average of 0.47 mol of [125I] thyroxine was incorporated per mol protein; nonspecific binding amounted to 8%. A labeled peptide fragment was isolated from a proteolytic digest of the derivatized protein by HPLC and its amino acid composition was determined. Comparison with the amino acid sequence of thyroxine-binding globulin indicated partial correspondence of the labeled peptide with two possible regions in the protein. These regions also coincide with part of the barrel structure present in the closely homologous protein, alpha 1-antitrypsin.

Thyroxine modifies the effects of growth hormone in Ames dwarf mice.

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Do, Andrew; Menon, Vinal; Zhi, Xu; Gesing, Adam; Wiesenborn, Denise S; Spong, Adam; Sun, Liou; Bartke, Andrzej; Masternak, Michal M

2015-04-01

Ames dwarf (df/df) mice lack growth hormone (GH), thyroid stimulating hormone and prolactin. Treatment of juvenile df/df mice with GH alone stimulates somatic growth, reduces insulin sensitivity and shortens lifespan. Early-life treatment with thyroxine (T4) alone produces modest growth stimulation but does not affect longevity. In this study, we examined the effects of treatment of juvenile Ames dwarf mice with a combination of GH + T4 and compared them to the effects of GH alone. Treatment of female and male dwarfs with GH + T4 between the ages of 2 and 8 weeks rescued somatic growth yet did not reduce lifespan to match normal controls, thus contrasting with the previously reported effects of GH alone. While the male dwarf GH + T4 treatment group had no significant effect on lifespan, the female dwarfs undergoing treatment showed a decrease in maximal longevity. Expression of genes related to GH and insulin signaling in the skeletal muscle and white adipose tissue (WAT) of female dwarfs was differentially affected by treatment with GH + T4 vs. GH alone. Differences in the effects of GH + T4 vs. GH alone on insulin target tissues may contribute to the differential effects of these treatments on longevity.

A clinical study on 125I T3 resin uptake rate and serum thyroxin (T4) in hyperthyroidism

International Nuclear Information System (INIS)

Moon, E.S.; Park, Y.H.; Cho, C.H.; Park, I.S.; Lee, C.S.; Lee, H.C.

1978-01-01

Total of 94 cases of hyperthyroidism were classified as toxic diffuse goiter (77 case) as toxic adematous goiter (8 case) and as toxic multinodular goiter (9 case) on the levels of T 3 - 125 I resin uptake rate and the measurement of serum T 4 levels. Various clinical symptoms and diagnostic characteristics were discussed. (author)

Changes and clinical significance of CD4+CD25+CD127- regulatory T cells in Graves disease

International Nuclear Information System (INIS)

Zou Jintao; Yu Peiling; Dong Jingwei; Liao Qihong; Liu Dongliang; Zeng Hongyi

2012-01-01

Objective: To investigate the mechanism of Graves disease by observing the changes of CD4 + CD25 + CD127 - regulatory T cells (Treg) population in the patients. Methods: Flow cytometry was used to detect the proportion of CD4 + CD25 + CD127 - Treg of CD4 + T cells in 90 Graves disease patients (Graves disease group) and 50 healthy adults (control group). Thyroid function and autoantibody levels were determined simultaneously. The t test was adopted for comparison between groups. The relationship between CD4 + CD25 + CD127 - Treg and thyroid function was analyzed by linear correlation analysis. Results: The percentages of CD4 + CD25 + CD127 - Treg in Graves disease group and control group were 1.39%±1.09% and 4.59%±1.14% separately. There was significant difference between the two groups (t=16.4, P<0.01). There were negative correlation between CD4 + CD25 + CD127 - Treg percentages and total triiodothyronine, total thyroxine,free triiodothyronine, free thyroxine and thyrotropin receptor antibody,thyroglobulin antibody, thyroid microsomal antibody (r=-0.62, -0.65, -0.56, -0.71, -0.50, -0.15, all P<0.01). Conclusions: The reduction of CD4 + CD25 + CD127 - Treg percentages in Graves disease group and close relations of CD4 + CD25 + CD127 - Treg with thyroid function and thyroid autoantibody levels suggest that CD4 + CD25 + CD127 - Treg decrease in the number may be associated with the onset of Graves disease. CD4 + CD25 + CD127 - may be the specific marker of Treg. (authors)

A randomized, masked study of triiodothyronine plus thyroxine administration in preterm infants less than 28 weeks of gestational age: Hormonal and clinical effects

NARCIS (Netherlands)

Valerio, Paolo G.; van Wassenaer, Aleid G.; de Vijlder, Jan J. M.; Kok, Joke H.

2004-01-01

A randomized, placebo-controlled, masked study was conducted of the responses of thyroid parameters, cortisol, and the cardiovascular system to a single dose of triiodothyronine (T-3) 24 h after birth, followed by a daily dose of thyroxine (T-4) during 6 wk to infants <28 wk gestational age.

Thyroxine treatment may be useful for subclinical hypothyroidism in patients with female infertility.

Science.gov (United States)

Yoshioka, Waka; Amino, Nobuyuki; Ide, Akane; Kang, Shino; Kudo, Takumi; Nishihara, Eijun; Ito, Mitsuru; Nakamura, Hirotoshi; Miyauchi, Akira

2015-01-01

Infertile women sometimes associated with subclinical hypothyroidism (SCH). The guidelines of the American Endocrine Society, and American Association of Clinical Endocrinologists and American Thyroid Association recommend treatment with thyroxine (T4) for patients with SCH who want to have children. We examined 69 female infertile patients with SCH and the effects of levothyroxine (l-T4) therapy on pregnancy rates and pregnancy outcomes were observed. Fifty-eight (84.1%) patients successfully conceived during the T4 treatment period (Group A), although 17 patients (29.3%) had miscarriage afterward. The remaining 11 patients continued to be infertile (Group B). The median TSH value in Group A before the T4 treatment was 5.46 μIU/mL (range 3.1-13.3) and this significantly decreased to 1.25 μIU/mL (range 0.02-3.75) during the treatment (ptreatment was 2.8±1.7 years and the duration until pregnancy after the treatment was significantly shorter at 0.9±0.9 years (ptreatment strongly suggest that T4 enhanced fertility in infertile patients with SCH.

Competitive protein binding analysis for thyroxine using Sephadex column (Tetralute)

International Nuclear Information System (INIS)

Miyai, Kiyoshi; Katayama, Yoshiaki; Sawazaki, Norio; Ishibashi, Kaichiro; Kawashima, Minoru.

1975-01-01

The method of competitive protein binding analysis of thyroxine (T 4 ) using Tetralute kit was evaluated. The net retention was decreased when the procedure of competition and separation was performed at a higher temperature but the final T 4 -I values were constant when the standard and test sera were treated identically. Coefficient of variation (C.V.) was 4% (within-assay) and 6% (between-assay) respectively. However, the T 4 -I values of pooled serum for quality control were slightly lower in earlier experiments in which correction factors (1.03--1.62 in 18 out of 21 assays) were necessary. T 4 -I values were determined by the Tetralute in 155 cases. They were as follows: 4.9+-0.8 μg/dl (euthyroid subjects), 6.4+-1.2 μg/dl (cord serum), 7.1+-1.1 μg/dl (pregnant women). 9.0+-3.6 μg/dl (trophoblastic disease), 13.3+-4.8 μg/dl (Graves' disease), 6.3+-1.6 μg/dl (Plummer's disease), 4 -I values determined by Tetralute and Res-O-Mat T 4 (r=0.96). Following oral administration of Telepaque the serum protein-bound iodine was markedly elevated, while the T 4 -I determined by Tetralute did not change. In vitro addition of diphenylhydantoin (500 μg/ml), salicylate (4 mg/ml) and phenobarbital (1 mg/ml) had no or little effect on T 4 determination by Tetralute. A high concentration of benzbromarone (0.1 mg/ml) caused a higher value of T 4 -I determined by Tetralute when added to a TBG solution but there was only a slight increase when it was added to serum. (auth.)

[Partial thyroxine binding globulin deficiency in test tube infants: report of cases and literature review].

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Fang, Y L; Wang, C L; Liang, L

2016-06-02

To investigate the clinical characteristics of twins with thyroxine binding globulin (TBG) deficiency and to find SERPINA7 gene mutations. Data(2015) related to clinical characteristics, serum biochemistry, gene mutations and pedigree of two children with TBG deficiency were collected in the First Affiliated Hospital of College of Medicine, Zhejiang University. The related literature was searched form China National Knowledge Infrastructure, Wanfang Data Knowledge Service Platform, National Center for Biotechnology Information and PubMed (up to December 2015) by using search terms "Thyroxine binding globulin deficiency, gene, mutation" . Both patients were diagnosed as central hypothyroidism at the beginning and treated with L-thyroxine. Both of the identical twins of the triplet were observed for mutation in exon3, c. 631G﹥A(p.A211T), a new mutation had not been reported, but their parents and another non-identical triplet brother were normal. Literature review showed that 23 foreign cases with SERPINA7 gene mutation had been reported, however, no Chinese with SERPINA7 gene mutation had been reported. Among reported cases it was shown that SERPINA7 gene mutations located in exon, intron, promoter and enhancer. Up to now, 49 variants had been identified, 41 of them located in the mutated genes. Including these two cases, patients with thyroxine binding globulin deficiency were characterized by reduced serum TH levels, but normal free TH and TSH and absence of clinical manifestations. The new mutation of SERPINA7 gene c. 631G﹥A(p.A211T)is not transmitted via the known X chromosome linked heredity, and as the cases were test tube triplet infants, it is a de novo mutation. The serum thyroid function tests of TBG deficiency showed decreased TT4, TT3 and normal TSH and TBG deficiency is often misdiagnosed as central hypothyroidism.

Exogenous thyroxine improves glucose intolerance in insulin-resistant rats.

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Vazquez-Anaya, Guillermo; Martinez, Bridget; Soñanez-Organis, José G; Nakano, Daisuke; Nishiyama, Akira; Ortiz, Rudy M

2017-03-01

Both hypothyroidism and hyperthyroidism are associated with glucose intolerance, calling into question the contribution of thyroid hormones (TH) on glucose regulation. TH analogues and derivatives may be effective treatment options for glucose intolerance and insulin resistance (IR), but their potential glucoregulatory effects during conditions of impaired metabolism are not well described. To assess the effects of thyroxine (T 4 ) on glucose intolerance in a model of insulin resistance, an oral glucose tolerance test (oGTT) was performed on three groups of rats (n = 8): (1) lean, Long Evans Tokushima Otsuka (LETO), (2) obese, Otsuka Long Evans Tokushima Fatty (OLETF) and (3) OLETF + T 4 (8.0 µg/100 g BM/day × 5 weeks). T 4 attenuated glucose intolerance by 15% and decreased IR index (IRI) by 34% in T 4 -treated OLETF compared to untreated OLETF despite a 31% decrease in muscle Glut4 mRNA expression. T 4 increased the mRNA expressions of muscle monocarboxylate transporter 10 (Mct10), deiodinase type 2 (Di2), sirtuin 1 (Sirt1) and uncoupling protein 2 (Ucp2) by 1.8-, 2.2-, 2.7- and 1.4-fold, respectively, compared to OLETF. Activation of AMP-activated protein kinase (AMPK) and insulin receptor were not significantly altered suggesting that the improvements in glucose intolerance and IR were independent of enhanced insulin-mediated signaling. The results suggest that T 4 treatment increased the influx of T 4 in skeletal muscle and, with an increase of DI2, increased the availability of the biologically active T 3 to upregulate key factors such SIRT1 and UCP2 involved in cellular metabolism and glucose homeostasis. © 2017 Society for Endocrinology.

Treatment of subclinical hypothyroidism in pregnancy using fixed thyroxine daily doses of 75 μg.

Science.gov (United States)

Penin, Manuel; Trigo, Cristina; López, Yolanda; Barragáns, María

2014-01-01

Treatment of hypothyroid pregnant women is usually calculated based on weight (1 μg/kg/day) and TSH levels. This study assessed the usefulness of treating these women with a fixed dose of 75 μg/day. All women with pregnancy diagnosed from January to August 2012 in the Vigo Health Area (Spain) without previous diagnosis of thyroid disease or thyroxine treatment and with TSH levels over 4,5 mUI/ml were enrolled by consecutive sampling. All 116 women in the sample were treated with a fixed daily dose of thyroxine 75 μg-thyroxine levels were measured at two, four, and six months, and thyroxine dose was modified if TSH level was lower than 0.3 or higher than 4.5 mUI/ml. A woman had a TSH level less than 0.3 mUI/ml in a test; reduction of thyroxine dose to 50 μg/day allowed for maintaining TSH level within the desired range until delivery. Six women had TSH levels over 4.5 mUI/ml in one test; in all of them, increase in thyroxine dose to 100 μg/day allowed for maintaining the level within the desired range until delivery. Fixed daily doses of thyroxine 75 μg allowed for achieving goal TSH levels in most of our pregnant women with subclinical hypothyroidism, irrespective of their weight and baseline TSH level. Copyright © 2013 SEEN. Published by Elsevier Espana. All rights reserved.

Do Thyroxine and Thyroid-Stimulating Hormone Levels Reflect Urinary Iodine Concentrations?

Science.gov (United States)

Soldin, Offie P.; Tractenberg, Rochelle E.; Pezzullo, John C.

2013-01-01

The toxicity of environmental chemicals such as nitrates, thiocynates, and perchlorates, some therapeutics, and dietary goitrogens can lower thyroidal iodine uptake and result in hypothyroidism and goiter. Iodine sufficiency, essential for normal thyroid hormone synthesis, is critical during gestation to assure that sufficient thyroxine (T4) and iodine reach the developing fetus. Spot urinary iodide (UI) measurements are used globally to indicate and monitor iodine sufficiency of populations. In individuals, however, UI are not routinely measured; instead, normal serum thyroid-stimulating hormone (TSH) and T4 concentrations serve as surrogate indicators of iodine sufficiency as well as thyroidal health. Our objective was to examine the relationship between UI concentrations and serum T4 and TSH concentrations in individuals in an ‘‘iodine-sufficient population.’’ Using a cross-sectional sample of the US population (n = 7628) from the National Health and Nutrition Examination Survey (NHANES III; 1988–1994) database, we examined the relationship among UI, T4, and TSH in pregnant and nonpregnant women and in men (15–44 years). There was a lack of relationship between UI (or UI/Cr) concentrations and serum T4 or TSH concentrations. Therefore, TSH and T4 are not appropriate markers of UI concentrations in this population. Monitoring the status of iodine nutrition of individuals in the United States may be important because serum TSH and T4 concentrations do not indicate low iodine status. PMID:15795649

Radioimmunoassay of thyroxine and triiodothyronine in urine using extraction and separation on Sephadex columns

International Nuclear Information System (INIS)

Rogowski, P.; Siersbaek-Nielsen, K.

1977-01-01

Radioimmunological methods for the determination of thyroxine (T4) and triiodothyronine (T3) in urine have been developed. The methods are based on trapping of T4 and T3 from unextracted urine, followed by separation between free and antibody bound hormone on the same Sephadex column. The T4 method has been compared to a competitive protein binding (CPB) assay using ethyl acetate extraction. The methods are evaluated in sixty-seven euthyroid controls, twenty-four hyperthyroid and seven hypothyroid patients. In the T4 RIA detection limit was 3.9 pg, intra-assay coefficient of variation (cv) was 5.2% and inter-assay cv was 6.9%. In the T3 RIA detection limit was 7.2 pg, intra-assay cv 3.9% and inter-assay cv 10.8%. Recovery of added amounts of hormones and serial dilutions gave satisfactory results. The CPB assay was found unreliable with unspecific and false high values. In euthyroid controls 24 h urinary T4 excretion as measured by RIA was 1.8+-0.5 nmol, and urinary T3 excretion was 0.7+-0.3 nmol. T4 and T3 excretion was greatly elevated in hyperthyroid patients and decreased in hypothyroidism. (Auth.)

Effects of thyroxine on the migration of hippocampal neurons in newborn rat exposed to HTO

International Nuclear Information System (INIS)

Cai Erpeng; Qiu Jun; Wang Yongsheng; Wu Cuiping; Yao Xiaobo; Wang Mingming

2012-01-01

Objective: To explore the effect of thyroxine (TH) on the migration of hippocampal neurons in newborn rat exposed to tritiated water (HTO). Methods: The hippocampal neurons from neonatal rats were primarily cultured, 7 days later, randomly divided into control group, HTO group, TH group and HTO + TH group (3.7 × 10 5 Bq/ml HTO and 0.3 μg/ml TH were simultaneously added). After 24 h, the distance of neuronal migration was measured with Leica AF 6000, the expressions of BDNF and Reelin mRNA in neurons were analyzed with reverse transcription polymerase chain reaction (RT-PCR), the expression of β-tubulin protein in neurons was assayed with Western blot and immunocytochemical staining. Results: Compared with control group, the expression of Reelin mRNA, BDNF mRNA and β-tubulin in HTO group were significantly reduced (t=5.80, 5.48, 5.47, P<0.01), but those in HTO + TH group and TH group were obviously increased (t=7.75, 12.06, 13.65, P<0.01; t=4.34, 5.47, 5.65, P<0.01) and higher than that in HTO group (t=2.92, 10.32, 8.76, P<0.01; t=18.07, 20.55, 40.13, P<0.01). Accordingly, the neuronal migration distance in HTO group was much shorter than that in control (t=8.62, P<0.01), and in HTO + TH group and TH group was far longer than that in control (t=7.64, 4.93, P<0.01). Moreover, the neuronal migration distance in HTO + TH group was notably elongated in comparison with that in HTO group (t=11.32, 12.31, P<0.01). Conclusions: Thyroxine may promote the migration of hippocampal neurons in newborn rat exposed to HTO. (authors)

Early thyroxine treatment in Down syndrome and thyroid function later in life.

Science.gov (United States)

Zwaveling-Soonawala, Nitash; Witteveen, M Emma; Marchal, Jan Pieter; Klouwer, Femke C C; Ikelaar, Nadine A; Smets, Anne M J B; van Rijn, Rick R; Endert, Erik; Fliers, Eric; van Trotsenburg, A S Paul

2017-05-01

The hypothalamus-pituitary-thyroid (HPT) axis set point develops during the fetal period and first two years of life. We hypothesized that thyroxine treatment during these first two years, in the context of a randomized controlled trial (RCT) in children with Down syndrome, may have influenced the HPT axis set point and may also have influenced the development of Down syndrome-associated autoimmune thyroiditis. We included 123 children with Down syndrome 8.7 years after the end of an RCT comparing thyroxine treatment vs placebo and performed thyroid function tests and thyroid ultrasound. We analyzed TSH and FT4 concentrations in the subgroup of 71 children who were currently not on thyroid medication and had no evidence of autoimmune thyroiditis. TSH concentrations did not differ, but FT4 was significantly higher in the thyroxine-treated group than that in the placebo group (14.1 vs 13.0 pmol/L; P  = 0.02). There was an increase in anti-TPO positivity, from 1% at age 12 months to 6% at age 24 months and 25% at age 10.7 years with a greater percentage of children with anti-TPO positivity in the placebo group (32%) compared with the thyroxine-treated group (18.5%) ( P  = 0.12). Thyroid volume at age 10.7 years (mean: 3.4 mL; range: 0.5-7.5 mL) was significantly lower ( P  treatment during the first two years of life led to a mild increase in FT4 almost 9 years later on and may point to an interesting new mechanism influencing the maturing HPT axis set point. Furthermore, there was a trend toward less development of thyroid autoimmunity in the thyroxine treatment group, suggesting a protective effect of the early thyroxine treatment. Lastly, thyroid volume was low possibly reflecting Down-specific thyroid hypoplasia. © 2017 European Society of Endocrinology.

Selective affinity labeling of a 27-kDa integral membrane protein in rat liver and kidney with N-bromoacetyl derivatives of L-thyroxine and 3,5,3'-triiodo-L-thyronine

International Nuclear Information System (INIS)

Koehrle, J.R.; Rasmussen, U.B.; Rokos, H.; Leonard, J.L.; Hesch, R.D.

1990-01-01

125I-Labeled N-bromoacetyl derivatives of L-thyroxine and L-triiodothyronine were used as alkylating affinity labels to identify rat liver and kidney microsomal membrane proteins which specifically bind thyroid hormones. Affinity label incorporation was analyzed by ethanol precipitation and individual affinity labeled proteins were identified by autoradiography after separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions. Six to eight membrane proteins ranging in size from 17 to 84 kDa were affinity labeled by both bromoacetyl-L-thyroxine (BrAcT4) and bromoacetyl-L-triiodothyronine (BrAcT3). Affinity labeling was time- and temperature-dependent, and both reduced dithiols and detergents increased affinity labeling, predominantly in a 27-kDa protein(s). Up to 80% of the affinity label was associated with a 27-kDa protein (p27) under optimal conditions. Affinity labeling of p27 by 0.4 nM BrAc[125I]L-T4 was blocked by 0.1 microM of the alkylating ligands BrAcT4, BrAcT3, or 100 microM iodoacetate, by 10 microM concentrations of the non-alkylating, reversible ligands N-acetyl-L-thyroxine, 3,3',5'-triiodothyronine, 3,5-diiodosalicylate, and EMD 21388, a T4-antagonistic flavonoid. Neither 10 microM L-T4, nor 10 microM N-acetyltriiodothyronine or 10 microM L-triiodothyronine blocked affinity labeling of p27 or other affinity labeled bands. Affinity labeling of a 17-kDa band was partially inhibited by excess of the alkylating ligands BrAcT4, BrAcT3, and iodoacetate, but labeling of other minor bands was not blocked by excess of the competitors. BrAc[125I]T4 yielded higher affinity label incorporation than BrAc[125I]T3, although similar banding patterns were observed, except that BrAcT3 affinity labeled more intensely a 58,000-Da band in liver and a 53,000-55,000-Da band in kidney

Thyroxine and triiodothyronine content in commercially available thyroid health supplements.

Science.gov (United States)

Kang, Grace Y; Parks, Jonathan R; Fileta, Bader; Chang, Audrey; Abdel-Rahim, Maged M; Burch, Henry B; Bernet, Victor J

2013-10-01

As defined by the Dietary Supplement Health and Education Act 1997, such substances as herbs and dietary supplements fall under general Food and Drug Administration supervision but have not been closely regulated to date. We examined the thyroid hormone content in readily available dietary health supplements marketed for "thyroid support." Ten commercially available thyroid dietary supplements were purchased. Thyroid supplements were dissolved in 10 mL of acetonitrile and water with 0.1% trifloroacetic acid and analyzed using high-performance liquid chromatography for the presence of both thyroxine (T4) and triiodothyronine (T3) using levothyroxine and liothyronine as a positive controls and standards. The amount of T4 and T3 was measured separately for each supplement sample. Nine out of 10 supplements revealed a detectable amount of T3 (1.3-25.4 μg/tablet) and 5 of 10 contained T4 (5.77-22.9 μg/tablet). Taken at the recommended dose, 5 supplements delivered T3 quantities of greater than 10 μg/day, and 4 delivered T4 quantities ranging from 8.57 to 91.6 μg/day. The majority of dietary thyroid supplements studied contained clinically relevant amounts of T4 and T3, some of which exceeded common treatment doses for hypothyroidism. These amounts of thyroid hormone, found in easily accessible dietary supplements, potentially expose patients to the risk of alterations in thyroid levels even to the point of developing iatrogenic thyrotoxicosis. The current study results emphasize the importance of patient and provider education regarding the use of dietary supplements and highlight the need for greater regulation of these products, which hold potential danger to public health.

Effects of thyroxin therapy on different analytes related to obesity and inflammation in dogs with hypothyroidism.

Science.gov (United States)

Tvarijonaviciute, A; Jaillardon, L; Cerón, J J; Siliart, B

2013-04-01

Hypothyroidism in dogs is accompanied by changes in intermediary metabolism including alterations in bodyweight (BW), insulin resistance, and lipid profile. In this study, changes in selected adipokines (adiponectin, leptin), butyrylcholinesterase (BChE), and acute phase proteins, including C-reactive protein, haptoglobin (Hp) and serum amyloid A (SAA), were studied in dogs with hypothyroidism under thyroxin therapy. Blood samples were collected when hypothyroidism was diagnosed (before treatment) and after treatment with thyroxin. Twenty-eight of 39 dogs exhibited a good therapeutic response (group A), whereas the remainder were considered to have been insufficiently treated (group B). Following treatment, group A dogs demonstrated a statistically significant decrease in canine thyroid stimulating hormone (c-TSH) (P<0.001) and an increase in free thyroxine (fT4) (P<0.001) concentrations, associated with a significant decrease in BW (P<0.05), leptin (P<0.01), and adiponectin, (P<0.001) and an increase in BChE (P<0.01) and Hp (P<0.05). Group B dogs showed no statistically significant changes in c-TSH, but had a significant increase in fT4 (P<0.001) accompanied by a significant decrease in adiponectin (P<0.05) of lower magnitude than group A. No significant changes in the mean circulating levels of APPs were observed in both groups, with the exception of an increase in Hp (P<0.05) in group A. In summary, the successful treatment of hypothyroidism reduces circulating levels of adiponectin and leptin, while increasing BChE activity in dogs. The mean increase in Hp values and decrease in SAA for some of the dogs after treatment warrants further investigation. Copyright © 2012 Elsevier Ltd. All rights reserved.

Acute mania after thyroxin supplementation in hypothyroid state

Directory of Open Access Journals (Sweden)

Rohit Verma

2013-01-01

Full Text Available The current literature variedly ascribes depressive and manic symptoms to hypo- and hyperthyroid state, respectively, reporting mania in hypothyroidism as an unusual entity. More unusual is precipitation of manic state in hypothyroid subjects after thyroxine supplementation for which studies report otherwise treating manic symptoms in hypothyroid state with thyroxine. We report a case of a patient whose acute mania appears to have been precipitated by thyroxine supplementation in hypothyroidism state. This case underscores the importance of thyroid screening in patients with mood and psychotic disorders, as well as the potency of thyroxine in producing manic symptoms.

Development of reagents for radioimmunoassay of: triiodothyronine, thyroxine and thyrotrophin

International Nuclear Information System (INIS)

Delgado S, B.; Lavalley E, C.; Ruiz J, A.; Garcia F, C.; Zamorano A, F.

1991-12-01

The radioimmunoassay (RIA) of thyroid hormones it is the but it frequents of all the studies carried out by RIA in the laboratories of Nuclear Medicine, these essays are carried out with imported reagents. In the ININ the reagents and the necessary methodology have been developed for the triiodothyronine (T3), thyroxine (T4) and thyrotrophin (TSH). The good titles of the antibodies (Ac) primary for each hormone were of 1:4,000; 1:750 and 1:1,500. The used separation system was of double Ac with PEG to 10%, with titles of 1:10 for the second Ac of lamb. The specific activity for 125-I-T3 and 125-I-T4 oscillate between 850 at 900 μCi / μ g: being this of 90 μ Ci /μg for TSH. To the first two hormones they were added 1-8 aniline naftalen sulfonic acid (ANS) to concentrations of 3 and 2 mg/ml respectively. As buffer for T3 and T4 it was used Tris-HCl pH 8.6 and PBS with normal serum of rabbit (SNC) for TSH. The standards got ready in buffer or free serum of thyroid hormones. The slope of the standard curves varied between -2.3 to -2.7 and the variation intra and inter assay among 4 to 10%. It is had at the moment in the ININ with standardized reagents for the RIA of T3, T4 and TSH, it is hoped to carry out tests in other laboratories and to establish the conditions of stability more appropriate to begin the preparation of pilot reagents. (Author)

Preparation of second antibody enhanced coated tubes for radioimmunoassay of triiodothyronine and thyroxine

International Nuclear Information System (INIS)

Mehany, N.L.; El-Kolaly, M.T.; Ghonaim, A.; Abdelmouhty, N.R.

1999-01-01

The production of high technology RIA reagents with low cost is considered to be one of the important goal of labelled compounds dept., Radioisotope production division, hot labs centre, egyptian atomic energy authority. The development of a direct radioimmunoassay for the measurement of triiodothyronine (T 3 ) and thyroxine (T 4 ) in human serum is described. The coating of polystyrene tubes with affinity purified second antibody (Donkey antisheep antibody, DASS) followed by sheep polyclonal antisera specific for each of T 3 and T 4 was carried out. The stability study of these coated tubes revealed that these tubes could stored for at least one year at 4degree C without any appreciable reduction in binding. The assays were performed by adding 200 MU1 radiolabelled hormones ( 125 I - T 3 or 125 I - T 4 ) to standards, unknown samples or quality controls (50 MU1 10 MU1 for T 3 and T 4 , respectively ) into corresponding assay tubes. The reaction is allowed to proceed at 37degree C for 2h and 1h for T 3 and T 4 respectively. Then the tubes were decanted, washed and counted. Twenty human serum samples of different thyroid disorders were analyzed for T 3 and T 4 using the present systems and with commercially available kits (DOC, coated tubes). The statistical analysis showed good correlations between the results obtained from the present systems and the DPC kits (r = 0.994 and 0.990 for T 3 and T 4 respectively). Hypothyroid, euthyroid and hyperthyroid subjects are reasonably and accurately distinguished using our methods

Thyroxin hormone suppression treatment

International Nuclear Information System (INIS)

Samuel, A.M.

1999-01-01

One of the important modalities of treatment of thyroid cancer (TC) after surgery is the administration of thyroxin as an adjuvant treatment. The analysis supports the theory that thyroid suppression plays an important role in patient management. 300 μg of thyroxin, as this is an adequate dose for suppression is given. Ideally the dose should be tailored by testing s-TSH levels. However, since a large number of the patients come from out station cities and villages this is impractical. We therefore depend on clinical criteria of hyperthyroid symptoms and adjust the dose. Very few patients need such adjustment

Concepts for the assay of unbound thyroxine (FT4) and thyroxine binding globulin (TBG)

International Nuclear Information System (INIS)

Odstrchel, G.; Hertl, W.; Ward, F.B.; Travis, K.; Lindner, R.E.; Mason, R.D.

1977-01-01

Two new concepts for the assay of thyroid related substances are presented. One assay (FT 4 ) is based on a kinetic measurement of T 4 as it desorbs from binder proteins onto solid-phase T 4 antibody. This reaction can be described by a second order rate equation; r = k (IMA) (FT 4 ). The assay is rapid (2 hours) and gives good agreement (sigma = 0.92) with equilibrium dialysis and a normal range of 0.9 - 2.3 ng/dl. This assay uses a small sample size (25 μl) and is unaffected by drugs such as aspirin and dilantin. Pregnant and estrogen treated women gave normal FT 4 values. A new method for the measurement of functionally active TEG is also presented. In this case the labeled T 4 is partitioned between bovine serum albumin and the patient's samples. The complex is then removed from solution by solid-phase anti-TBG. A curve remiscent of an immunoradiometric assay is obtained. The assay has a sensitivity of 4 μg/ml and is unaffected by aspirin, dilantin or the patient's T 4 concentrations. Correlation with 'rocket' electrophoresis is 0.90. The normal range was 20 +- 7 μg/ml with pregnant women giving values greater than 30 μg/ml. Five hereditary deficient patients gave a value equivalent to zero TBG concentration. (orig.) [de

Quality characteristics of chemicals for the radioimmunoassay of thyroxine and thyrotropin

International Nuclear Information System (INIS)

Verdeja I, C.E.

1994-01-01

Radioimmunoassay is a form of saturation analysis in which the test material competes with labelled antigen for a limited amount of antibody, the amount of label displaced being a measure of the antigen in the test sample. In this country, the kits for Radioimmunoassay (RIA) are imported, and this increase the cost of it. Because this lack of production, the National Institute of Nuclear Research (ININ) has developed RIA's kits for the thyroxine (T 4 ), Thyrotropin (TSH) and Triyodotironine (T 3 ) hormones. This work presents the conclusions of the test recommended by the WHO. The quality test were: recuperation, cross reactions, basic parameters, intra and inter assay variations, sensibility and others. The results show that the RIA's kits of the ININ have a good behavior and can be use in the clinical laboratory. (Author)

Neonatal hypothyrodism: assessment of a commercial kit in which filter-paper discs are used for thyroxine radioimmunoassay. [/sup 125/I tracer technique

Energy Technology Data Exchange (ETDEWEB)

Kubasik, N.P.; Warren, K.; Sine, H.E.

1977-11-01

The /sup 125/I-Neonatal T/sub 4/ RIA kit is described and evaluated. It is concluded that the kit has acceptable precision and recovery and gives results that correlate well with venous concentrations of circulating thyroxine to allow its use in a congenital hypothyroid screening program. (HLW)

A method of radiocompetitive assay of total thyroxine in the serum by means of enzymatic release of thyroxine from the transporting proteins

International Nuclear Information System (INIS)

Snarski, A.; Wyrwinski, J.

1978-01-01

Pepsin causes denaturation of the transporting proteins and liberates thyroxine which can be assayed by the radiocompetitive method. Change of the pH of the medium from acid to alkaline inactivates irreveribly pepsin. The enzymatic release of thyroxine is much simpler that the method of ethanol extraction and thermal denaturation of the transporting proteins applied up to now. The new technique of thyroxine release has been introduced for radiocompetitive determination of thyroxine using dextran coated charcoal for adsorption of the free hormone. A new method has been elaborated for preparation of working standards of thyroxine in a mixture of pepsin solution with hormone-free serum. The method is efficient and rapid. The normal range is from 50 to 130 nanomol/l. Over 7 000 determinations were done as yet in patients with suspected thyroid function disturbances. (author)

Effect of subclinical hypothyroidism on the skeletal system and improvement with short-term thyroxine therapy.

Science.gov (United States)

Gao, Cuixia; Wang, Yu; Li, Tingting; Huang, Jing; Tian, Limin

2017-10-27

The purpose of the study was to observe changes in the skeletal system of rats with subclinical hypothyroidism (SCH) and to determine whether L-thyroxine (L-T4) administration suppresses those changes. Sixty male Wistar rats were randomly divided into control, SCH, and SCH+T4 groups. SCH was induced in rats by administration of methimazole (MMI), and rats in the SCH+T4 group were treated with L-T4 after 45 days of MMI administration. The SCH group had higher thyroid-stimulating hormone (TSH) level than the control and SCH+T4 groups. There were no differences in serum thyroid hormone (FT4 and FT3) levels among the three groups. Bone mineral density; serum levels of BALP and TRACP-5b, two bone metabolic markers; and the biomechanical properties of the femurs were lower in the SCH group than in the control group. After L-T4 treatment, serum BALP and TRACP-5b levels and the femur biomechanical properties were higher in the SCH+T4 than the SCH group. Histopathological examination revealed damage to the structure of the femur trabecular bone network in rats with SCH, and L-T4 treatment improved this condition to some extent. These findings demonstrate that L-T4 treatment ameliorates the destructive effects of SCH on the skeletal system in rats.

Plasma proteome and metabolome characterization of an experimental human thyrotoxicosis model

DEFF Research Database (Denmark)

Pietzner, Maik; Engelmann, Beatrice; Kacprowski, Tim

2017-01-01

BACKGROUND: Determinations of thyrotropin (TSH) and free thyroxine (FT4) represent the gold standard in evaluation of thyroid function. To screen for novel peripheral biomarkers of thyroid function and to characterize FT4-associated physiological signatures in human plasma we used an untargeted O...

Role of beta adrenoceptors in the hypertrophic response to thyroxine

International Nuclear Information System (INIS)

Eliades, D.; Weiss, H.R.

1989-01-01

The ability of beta-adrenoceptor blockade to reduce the hypertrophic response to thyroxine (T4, 0.5 mg/kg per day, s.c.) was tested in New Zealand white rabbits. Two beta-adrenergic blocking agents, one a full antagonist (propranolol, 9.6 mg/kg per day) and the other a partial agonist (pindolol, 0.96 mg/kg per day) were administered in combination with T4 in an effort to reduce myocardial hypertrophy. A 3 and 16 day group were generated to test the time course of the hypertrophic and receptor responses. Coronary blood flow was measured using radioactive microspheres, and beta-adrenoceptor number and affinity were measured using 125I(-) pindolol as the radioligand. T4 increased coronary blood flow to 1.95 times control values in the 3 day group and 2.2 times control levels in the 16 day group; beta-adrenoceptor number was increased similarly in 3 and 16 day groups to 1.9 times control Bmax levels. Heart weight (HW) to body weight (BW) ratios were significantly increased in only the 16 day group to 1.22 and 1.61 times control, respectively. Treatment with propranolol + T4 blunted the coronary blood flow increase, but receptor upregulation occurred to the same extent as with either substance alone. The HW/BW was increased to 1.49 times control. Pindolol + T4 did not decrease coronary blood flow but blocked beta-adrenoceptor upregulation. The HW was reduced to control levels and the HW/BW ratio was 1.40 times control and significantly decreased from T4 alone. Thus, pindolol was effective in reducing the hypertrophic response to T4, whereas propranolol was only moderately effective in doing so

Exposure of Pregnant Mice to Triclosan Causes Insulin Resistance via Thyroxine Reduction.

Science.gov (United States)

Hua, Xu; Cao, Xin-Yuan; Wang, Xiao-Li; Sun, Peng; Chen, Ling

2017-11-01

Exposure to triclosan (TCS), an antibacterial agent, during pregnancy is associated with hypothyroxinemia and decreases in placental glucose transporter expression and activity. The objective of this study was to investigate the influence of TCS on glucose homeostasis and insulin sensitivity in gestational mice (G-mice) and nongestational female mice (Ng-mice) as a control. Herein, we show that the exposure of G-mice to TCS (8 mg/kg) from gestational day (GD) 5 to GD17 significantly increased their levels of fasting plasma glucose and serum insulin, and insulin content in pancreatic β-cells with reduced homeostasis model assessment (HOMA)-β index and increased HOMA-IR index. Area under curve (AUC) of glucose and insulin tolerance tests in TCS (8 mg/kg)-treated G-mice were markedly larger than controls. When compared with controls, TCS (8 mg/kg)-treated G-mice showed a significant decrease in the levels of thyroxine and triiodothyroninelevels, PPARγ and glucose transporter 4 (GLUT4) expression, and Akt phosphorylation in adipose tissue and muscle. Replacement of L-thyroxine in TCS (8 mg/kg)-treated G-mice corrected their insulin resistance and recovered the levels of insulin, PPARγ and GLUT4 expression, and Akt phosphorylation. Activation of PPARγ by administration of rosiglitazone recovered the decrease in Akt phosphorylation, but not GLUT4 expression. Although exposure to TCS (8 mg/kg) in Ng-mice reduced thyroid hormones levels, it did not cause the insulin resistance or affect PPARγ and GLUT4 expression, and Akt phosphorylation. The findings indicate that the exposure of gestational mice to TCS (≥8 mg/kg) results in insulin resistance via thyroid hormones reduction. © The Author 2017. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Comparative study on 2,2′,4,5,5′-pentachlorobiphenyl-mediated decrease in serum thyroxine level between C57BL/6 and its transthyretin-deficient mice

Energy Technology Data Exchange (ETDEWEB)

Kato, Yoshihisa, E-mail: kato@kph.bunri-u.ac.jp [Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki, Kagawa 769-2193 (Japan); Tamaki, Sekihiro [School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526 (Japan); Haraguchi, Koichi [Daiichi College of Pharmaceutical Sciences, Fukuoka 815-8511 (Japan); Ikushiro, Shin-ichi [Faculty of Engineering, Toyama Prefectural University, Toyama 939-0398 (Japan); Sekimoto, Masashi [School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526 (Japan); Ohta, Chiho [Faculty of Nutritional Sciences, Nakamura Gakuen University, Fukuoka 814-0198 (Japan); Endo, Tetsuya [Faculty of Pharmaceutical Sciences, Health Science University of Hokkaido, Hokkaido 061-0293 (Japan); Koga, Nobuyuki [Faculty of Nutritional Sciences, Nakamura Gakuen University, Fukuoka 814-0198 (Japan); Yamada, Shizuo; Degawa, Masakuni [School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526 (Japan)

2012-09-15

The relationships between the changes in the levels of serum total thyroxine (T{sub 4}), serum T{sub 4}-transthyretin (TTR) complex, and accumulation of T{sub 4} in tissues by 2,2′,4,5,5′-pentachlorobiphenyl (PentaCB) were examined using wild-type C57BL/6 (WT) and its TTR-deficient (TTR-null) mice. The constitutive level of serum total T{sub 4} was much higher in WT mice than in TTR-null mice. In WT mice 4 days after a single intraperitoneal injection with PentaCB (112 mg/kg), serum total T{sub 4} level was significantly decreased along with a decrease in serum T{sub 4}–TTR complex, and the levels of serum total T{sub 4} in the PentaCB-treated WT mice were almost the same to those in PentaCB-untreated (control) TTR-null mice. In addition, a slight decrease in serum total T{sub 4} by PentaCB treatment was observed in TTR-null mice. Furthermore, clearance of [{sup 125}I]T{sub 4} from the serum after [{sup 125}I]T{sub 4}-administration was promoted by the PentaCB-pretreatment in either strain of mice, especially WT mice. On the other hand, accumulation level of [{sup 125}I]T{sub 4} in the liver, but not in extrahepatic tissues, was strikingly enhanced in the PentaCB-pretreated WT and TTR-null mice. Furthermore, in both strains of mice, PentaCB-pretreatment led to significant increases in the steady-state distribution volume of [{sup 125}I]T{sub 4} and the concentration ratio of the liver to serum. The present findings demonstrate that PentaCB-mediated decrease in serum T{sub 4} level occurs mainly through increase in accumulation level of T{sub 4} in the liver and further indicate that the increased accumulation of T{sub 4} in the liver of WT mice is primarily dependent on the PentaCB-mediated inhibition of serum T{sub 4}–TTR complex formation.

Effect of selective blockade of oxygen consumption, glucose transport, and Ca2+ influx on thyroxine action in human mononuclear cells

DEFF Research Database (Denmark)

Kvetny, J; Matzen, L E

1990-01-01

The effect of selective blockade of cellular glucose transporters, Ca2+ influx, and mitochondrial oxygen consumption on thyroxine (T4)-stimulated oxygen consumption and glucose uptake was examined in human mononuclear blood cells. Blockade of glucose transporters by cytochalasin B (1 x 10(-5) mol....../L) and of Ca2+ influx by alprenolol (1 x 10(-5) mol/L) and verapamil (4 x 10(-4) mol/L) inhibited T4-activated glucose uptaken and reduced T4-stimulated oxygen consumption by 20%. Uncoupling of mitochondrial oxygen consumption by azide (1 x 10(-3) mol/L) inhibited T4-stimulated oxygen consumption, but had...... no effect on glucose uptake. We conclude that T4-stimulated glucose uptake in human mononuclear blood cells is dependent on intact glucose transporters and Ca2+ influx, but not on mitochondrial oxygen consumption. However, oxygen consumption is, in part, dependent on intact glucose uptake....

Radioimmunoassay detection of levels of triiodothyronine and thyroxine in Mangalarga Marchador equine; Niveis sericos de triiodotinonina e tiroxina, atraves de radioimunoensaio, em equinos Mangalarga Marchador

Energy Technology Data Exchange (ETDEWEB)

Viana, F.A.B.; Pessoa, J.M.; Biondini, J. [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Escola de Veterinaria

1991-12-31

Serum levels of triiodothyronine (T{sub 3}) and thyroxine (T{sub 4}) were determined in equine of Mangalarga Marchador breed through radioimmunoassay. Forty-two animals (17 males and 25 females), with age ranging from two to eighteen years, were utilized. The values recorded for males and females were, respectively: 101.68 {+-} 23.44 and 71.14 {+-} 18.82 ng/d l of T{sub 3} (P<0.05); 1.89 {+-} 0.58 and 2.94 {+-} 0.87 mc g/d l of T{sub 4} (P<0.05). (author). 10 refs, 1 tab.

Radioimmunoassay detection of levels of triiodothyronine and thyroxine in Mangalarga Marchador equine; Niveis sericos de triiodotinonina e tiroxina, atraves de radioimunoensaio, em equinos Mangalarga Marchador

Energy Technology Data Exchange (ETDEWEB)

Viana, F A.B.; Pessoa, J M; Biondini, J [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Escola de Veterinaria

1992-12-31

Serum levels of triiodothyronine (T{sub 3}) and thyroxine (T{sub 4}) were determined in equine of Mangalarga Marchador breed through radioimmunoassay. Forty-two animals (17 males and 25 females), with age ranging from two to eighteen years, were utilized. The values recorded for males and females were, respectively: 101.68 {+-} 23.44 and 71.14 {+-} 18.82 ng/d l of T{sub 3} (P<0.05); 1.89 {+-} 0.58 and 2.94 {+-} 0.87 mc g/d l of T{sub 4} (P<0.05). (author). 10 refs, 1 tab.

Assessment of a method for measuring serum thyroxine by radioimmunoassay, with use of polyethylene glycol precipitation

International Nuclear Information System (INIS)

Farid, N.R.; Kennedy, C.

1977-01-01

We assessed the efficacy of a new thyroxine radioimmunoassay kit (Abbott) in which polyethylene glycol is used to separate bound from free hormone. Mean serum thyroxine was 88 +- 15 (+-SD) μg/liter for 96 normal persons. Results for hypothyroid and hyperthyroid persons were clearly separated from those for normal individuals. Women taking oral contraceptive preparations showed variable increases in their serum thyroxine values. The coefficient of variation ranged from 1 to 3% within assay and from 5.4 to 11% among different assays. Excellent parallelism was demonstrated between thyroxine values estimated by this method and those obtained either by competitive protein binding or by a separate radioimmunoassay for the hormone

Multicompartmental model for iodide, thyroxine, and triiodothyronine metabolism in normal and spontaneously hyperthyroid cats

Energy Technology Data Exchange (ETDEWEB)

Hays, M.T.; Broome, M.R.; Turrel, J.M.

1988-06-01

A comprehensive multicompartmental kinetic model was developed to account for the distribution and metabolism of simultaneously injected radioactive iodide (iodide*), T3 (T3*), and T4 (T4*) in six normal and seven spontaneously hyperthyroid cats. Data from plasma samples (analyzed by HPLC), urine, feces, and thyroid accumulation were incorporated into the model. The submodels for iodide*, T3*, and T4* all included both a fast and a slow exchange compartment connecting with the plasma compartment. The best-fit iodide* model also included a delay compartment, presumed to be pooling of gastrosalivary secretions. This delay was 62% longer in the hyperthyroid cats than in the euthyroid cats. Unexpectedly, all of the exchange parameters for both T4 and T3 were significantly slowed in hyperthyroidism, possibly because the hyperthyroid cats were older. None of the plasma equivalent volumes of the exchange compartments of iodide*, T3*, or T4* was significantly different in the hyperthyroid cats, although the plasma equivalent volume of the fast T4 exchange compartments were reduced. Secretion of recycled T4* from the thyroid into the plasma T4* compartment was essential to model fit, but its quantity could not be uniquely identified in the absence of multiple thyroid data points. Thyroid secretion of T3* was not detectable. Comparing the fast and slow compartments, there was a shift of T4* deiodination into the fast exchange compartment in hyperthyroidism. Total body mean residence times (MRTs) of iodide* and T3* were not affected by hyperthyroidism, but mean T4* MRT was decreased 23%. Total fractional T4 to T3 conversion was unchanged in hyperthyroidism, although the amount of T3 produced by this route was increased nearly 5-fold because of higher concentrations of donor stable T4.

Multicompartmental model for iodide, thyroxine, and triiodothyronine metabolism in normal and spontaneously hyperthyroid cats

International Nuclear Information System (INIS)

Hays, M.T.; Broome, M.R.; Turrel, J.M.

1988-01-01

A comprehensive multicompartmental kinetic model was developed to account for the distribution and metabolism of simultaneously injected radioactive iodide (iodide*), T3 (T3*), and T4 (T4*) in six normal and seven spontaneously hyperthyroid cats. Data from plasma samples (analyzed by HPLC), urine, feces, and thyroid accumulation were incorporated into the model. The submodels for iodide*, T3*, and T4* all included both a fast and a slow exchange compartment connecting with the plasma compartment. The best-fit iodide* model also included a delay compartment, presumed to be pooling of gastrosalivary secretions. This delay was 62% longer in the hyperthyroid cats than in the euthyroid cats. Unexpectedly, all of the exchange parameters for both T4 and T3 were significantly slowed in hyperthyroidism, possibly because the hyperthyroid cats were older. None of the plasma equivalent volumes of the exchange compartments of iodide*, T3*, or T4* was significantly different in the hyperthyroid cats, although the plasma equivalent volume of the fast T4 exchange compartments were reduced. Secretion of recycled T4* from the thyroid into the plasma T4* compartment was essential to model fit, but its quantity could not be uniquely identified in the absence of multiple thyroid data points. Thyroid secretion of T3* was not detectable. Comparing the fast and slow compartments, there was a shift of T4* deiodination into the fast exchange compartment in hyperthyroidism. Total body mean residence times (MRTs) of iodide* and T3* were not affected by hyperthyroidism, but mean T4* MRT was decreased 23%. Total fractional T4 to T3 conversion was unchanged in hyperthyroidism, although the amount of T3 produced by this route was increased nearly 5-fold because of higher concentrations of donor stable T4

Trisomy 21 causes persistent congenital hypothyroidism presumably of thyroidal origin

NARCIS (Netherlands)

van Trotsenburg, A. S. Paul; Kempers, Marlies J. E.; Endert, Erik; Tijssen, Jan G. P.; de Vijlder, Jan J. M.; Vulsma, Thomas

2006-01-01

OBJECTIVE AND DESIGN: Lowered neonatal plasma thyroxine (T(4)) and mildly elevated thyrotropin concentrations together with developmental benefits from neonatally started T(4) treatment in a randomized clinical trial demonstrated Down syndrome (DS) neonates to be mildly hypothyroid, at least during

D-T plasma of self-sustained burning under high performance

International Nuclear Information System (INIS)

Gong Xueyu

2003-01-01

By adopting a Bohm-type thermal diffusion coefficient related to the energy confinement enhancement factor H within the conventional magnetic shear regime, and a mixed Bohm-gyro-Bohm thermal diffusion coefficient related to the shear within the negative central magnetic shear regime, considering the effect of the α particle anomalous diffusion and the dynamic feedback heating, and starting from energy transport of electrons and ions, we have studied the high performance self-sustaining burning deuterium-tritium plasma under a given plasma density profile for the two different kinds of magnetic shear regimes. Some conclusions are obtained: under the conventional shear, only when H≥3, the D-T burning can produce a large power output, and when H is larger than a certain value (H≅4), D-T plasma self-sustained burning can be maintained without the dynamic feedback heating; under the negative central shear, the plasmas have a higher plasma performance and a larger power output than that under conventional shear, and D-T plasma self-sustained burning can be maintained without the dynamic feedback heating power, the suitable alpha particle diffusion is advantage ous to D-T plasma burning under the conventional shear, and D-T self-sustained burning cannot be maintained under a large α particle anomalous diffusion for the negative central shear. The dynamic feedback heating power is important for sustaining D-T plasma burning under the conventional shear

Gestational exposure to high perchlorate concentrations in drinking water and neonatal thyroxine levels.

Science.gov (United States)

Amitai, Yona; Winston, Gary; Sack, Joseph; Wasser, Janice; Lewis, Matthew; Blount, Benjamin C; Valentin-Blasini, Liza; Fisher, Nirah; Israeli, Avi; Leventhal, Alex

2007-09-01

To assess the effect of gestational perchlorate exposure through drinking water on neonatal thyroxine (T(4)). T(4) values were compared among newborns in Ramat Hasharon, Israel, whose mothers resided in suburbs where drinking water contained perchlorate water exclusively (as determined by a telephone interview) were analyzed as a subset. Serum perchlorate levels in blood from donors residing in the area were used as proxy indicators of exposure. Neonatal T(4) values (mean +/- SD) in the very high, high, and low exposure groups were 13.9 +/- 3.8, 13.9 +/- 3.4, and 14.0 +/- 3.5 microg/dL, respectively (p = NS). Serum perchlorate concentrations in blood from donors residing in areas corresponding to these groups were 5.99 +/- 3.89, 1.19 +/- 1.37, and 0.44 +/- 0.55 microg/L, respectively. T(4) levels of neonates with putative gestational exposure to perchlorate in drinking water were not statistically different from controls. This study finds no change in neonatal T(4) levels despite maternal consumption of drinking water that contains perchlorate at levels in excess of the Environmental Protection Agency (EPA) drinking water equivalent level (24.5 microg/L) based on the National Research Council reference dose (RfD) [0.7 microg/(kg.day)]. Therefore the perchlorate RfD is likely to be protective of thyroid function in neonates of mothers with adequate iodide intake.

Fusion performances and alpha heating in future JET D-T plasmas

Energy Technology Data Exchange (ETDEWEB)

Balet, B; Cordey, J G; Gibson, A; Lomas, P; Stubberfield, P M; Thomas, P [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking

1994-07-01

The new pump divertor installed at JET should allow high performance pulses of a few seconds duration by both preventing the impurity influx and controlling the density evolution. The TRANSP code has been used in a predictive mode to assess the possible fusion performance of such plasmas fuelled with a 50:50 mixture of D and T, and the effect of alpha particles heating on Te and Ti. Several cases are considered: 50:50 D-T mix; 50:50 D-T mix, no C bloom; 50:50 D-T mix, VH phase, density control; 50:50 D-T mix, VH phase, density control, 6 Ma. The predictions show that if the the bloom and MHD instabilities can be controlled at higher plasma currents using a higher toroidal field to keep a reasonable beta value, then a higher fusion performance steady state plasma with Q{sub DT} superior to 2.5 should be possible. The alpha heating power of 4.9 MW would lead to a 74% increase in Te. 4 refs., 4 figs., 1 tab.

Effects of triiodothyronine on turnover rate and metabolizing enzymes for thyroxine in thyroidectomized rats.

Science.gov (United States)

Nagao, Hidenori; Sasaki, Makoto; Imazu, Tetsuya; Takahashi, Kenjo; Aoki, Hironori; Minato, Kouichi

2014-10-29

Previous studies in rats have indicated that surgical thyroidectomy represses turnover of serum thyroxine (T4). However, the mechanism of this process has not been identified. To clarify the mechanism, we studied adaptive variation of metabolic enzymes involved in T4 turnover. We compared serum T4 turnover rates in thyroidectomized (Tx) rats with or without infusion of active thyroid hormone, triiodothyronine (T3). Furthermore, the levels of mRNA expression and activity of the metabolizing enzymes, deiodinase type 1 (D1), type 2 (D2), uridine diphosphate-glucuronosyltransferase (UGT), and sulfotransferase were also compared in several tissues with or without T3 infusion. After the T3 infusion, the turnover rate of serum T4 in Tx rats returned to normal. Although mRNA expression and activity of D1 decreased significantly in both liver and kidneys without T3 infusion, D2 expression and activity increased markedly in the brain, brown adipose tissue, and skeletal muscle. Surprisingly, hepatic UGT mRNA expression and activity in Tx rats increased significantly in comparison with normal rats, and returned to normal after T3 infusion. This study suggests that repression of the disappearance of serum T4 in rats after Tx is a homeostatic response to decreased serum T3 concentrations. Additionally, T4 glucuronide is a storage form of T4, but may also have biological significance. These results suggest strongly that repression of deiodination of T4 by D1 in the liver and kidneys plays a major role in thyroid hormone homeostasis in Tx rats, and that hepatic UGT also plays a key role in this mechanism. Copyright © 2014 Elsevier Inc. All rights reserved.

Transthyretin-Binding Activity of Contaminants in Blood from Polar Bear (Ursus maritimus) Cubs

NARCIS (Netherlands)

Bytingsvik, J.; Simon, E.; Leonards, P.E.G.; Lamoree, M.H.; Lie, E.; Aars, J.; Derocher, A. E.; Wiig, O.; Jenssen, B.M.; Hamers, T.

2013-01-01

We determined the transthyretin (TTR)-binding activity of blood-accumulating contaminants in blood plasma samples of approximately 4-months-old polar bear (Ursus maritimus) cubs from Svalbard sampled in 1998 and 2008. The TTR-binding activity was measured as thyroxine (T4)-like equivalents (T4-EQ

Effects of caloric deprivation on thyroid hormone tissue uptake and generation of low-T3 syndrome

International Nuclear Information System (INIS)

van der Heyden, J.T.M.; Docter, R.; van Toor, H.; Wilson, J.H.P.; Hennemann, G.; Krenning, E.P.

1986-01-01

Changes in thyroid hormone metabolism in the low-3,5,3'-triiodothyronine (T 3 ) syndrome cannot be fully explained in all conditions by a decrease in 5'-deiodinase activity. Recent observations showed that in rat hepatocytes iodothyronines are taken up by an active transport mechanism. To investigate whether regulation, i.e., inhibition of active transmembraneous transport for iodothyronines in humans may contribute to the generation of the low-T 3 syndrome, tracer thyroxine (T 4 ) and T 3 kinetic studies were performed in 10 obese subjects before and after 7 days on a 240 kcal diet. Kinetics analyses were performed according to a three-pool model of distribution and metabolism for both T 4 and T 3 . For T 4 kinetics, during caloric deprivation serum total T 4 and plasma pool did not change and production rate and metabolic clearance rate (MCR) were significantly lower. Despite a significantly higher serum free T 4 , the mass transfer rate to the rapidly equilibrating pool (REP) and the slowly equilibrating pool (SEP) diminished significantly, leading to smaller tissue pools. For T 3 kinetics, both serum total T 3 , free T 3 , plasma pool, and production rate diminished significantly, while MCR remained unchanged. These changes cannot be fully explained by a similar decrease of serum free T 3 (only 25%), indicating a diminished transport efficiency for T 3 . In conclusion, during caloric restriction, transport of T 4 and T 3 into tissues is diminished, and this phenomenon is much more pronounced for T 4 transport per se may contribute to low-T 3 production and low-T 3 serum levels due to less substrate (i.e., T 4 ) availability in tissues

Serum thyroxine concentrations following fixed-dose radioactive iodine treatment in hyperthyroid cats: 62 cases (1986-1989)

International Nuclear Information System (INIS)

Meric, S.M.; Rubin, S.I.

1990-01-01

The medical records of 62 hyperthyroid cats treated with a fixed dose of 4 mCi of radioactive iodine (131I) were reviewed. In 60 cats, serum thyroxine concentrations were determined after treatment, allowing evaluation of treatment success. Eighty-four percent of the cats had normal serum thyroxine concentrations after treatment. Five of the 60 cats (8%) remained hyperthyroxinemic after treatment. Five cats (8%) were hypothyroxinemic when evaluated within 60 days of treatment. Three of these cats had normal serum thyroxine concentrations 6 months after treatment, and none had clinical signs of hypothyroidism. The administration of a fixed dose of 4 mCi of 131I was determined to be an effective treatment for feline hyperthyroidism

Unstimulated Thyroid Function Indices of Nigerians With Secondary Amenorrhea

Science.gov (United States)

Odum, C.U.; Giwa-Osagie, O.F.; Fregene, A.O.; Olajide, T.O.

1988-01-01

The unstimulated plasma thyroid indices of triiodothyronine uptake (T3U), thyroxine (T4), free thyroxine index (FTI), thyroid-stimulating hormone (TSH), and prolactin levels were measured in 56 patients who were complaining of secondary amenorrhea, and in 40 control patients. No significant differences were noted in the plasma indices between the two groups. Mean ± standard error plasma prolactin levels in patients with secondary amenorrhea and in the control patients were 21.8 ± 2 ng/mL and 10.5 ng/mL, respectively. Twenty-two (39 percent) patients who were complaining of amenorrhea had hyperprolactinemia and galactorrhea. The thyroid indices of these patients did not differ significantly from the control group. PMID:3385789

Direct and indirect parameters of free thyroxine. Pt. 2

International Nuclear Information System (INIS)

Reiners, C.; Hoffmann, R.; Moll, E.; Baum, K.; Becker, W.; Eilles, C.; Gerhards, W.; Schick, F.; Spiegel, W.; Wiedemann, W.; Boerner, W.

1983-01-01

Part II of the study concerning the clinical applicability of direct and indirect parameters for free thyroxine evaluates the diagnostic accuracy of the FT 4 -RIAs ImmoPhase, GammaCoat, Liquisol, Amerlex and LisoPhase in relation to FT 4 index and T 4 /TBG ratio. This comparison of methods is done on a thoroughly classified collection (n = 640) of patients with normal and impaired thyroid function including patients with binding protein anomalies (pregnancy, estrogen-medication, phenytoin therapy, renal protein loss). FT 4 normal ranges of a given kit harmonize well with data of the manufacturers and of the literature. On the other hand, the normal ranges of the various kits are not comparable. The differentiation of euthyroidism from hyper- or hypothyroidism can be made without problems using any of these methods, with the exception of the FT 4 -RIA GammaCoat. As expected, patients with euthyroid goiter show, on the average, slightly lower parameters for FT 4 . In pregnancy all direct and indirect parameters for FT 4 have a tendency to lower values after the first trimester. This trend is most distinct for the T 4 /TBG ratio. A weak negative correlation of FT 4 parameters with basal TSH, which does not exceed the upper normal range, however, can be interpreted in the sense of a relative hypothyroxinemia. Under contraceptive estrogen medication FT 4 parameters do not fall outside the normal range, with the exception of the FT 4 -RIA ImmoPhase assay which yields a significantly increased frequency of high FT 4 levels. (orig./RW) [de

The development of T3-RIA, T4-RIA and TSH-IRMA for in vitro testing of thyroid function

International Nuclear Information System (INIS)

Borza, V.; Neacsu, G.; Chariton, Despina

1998-01-01

Thyroxine (T 4 ) and triiodothyronine (T 3 ) are two principal thyroid hormones; the release of this hormones and control of different stages of their synthesis are performed by thyrotropin (TSH), secreted by pituitary gland. Also, T 3 and T 4 exert negative feed-back on the pituitary, inhibiting the release of TSH. The measurement of T 3 , T 4 content in un-extracted serum, correlated with TSH values are useful results for investigating the pituitary-thyroid axis. This paper describes radioimmunological procedures for the measurement of T 3 and T 4 using as separation method of the bound and free radiolabeled antigen, the precipitation of antigen-antibody complex by polyethyleneglycol (PEG). Antisera against T 3 , T 4 were produced by immunizing sheep with conjugates of the hormones and bovine albumin; T 3 and T 4 standards were made in horse serum free of these hormones. Binding of T 3 and T 4 to TBG in serum was inhibited by addition of 8-aniline-1-naphthalene-sulfonic acid (ANS). The separation of antigen-antibody complex was carried out using 25.5% PEG 6000. In order to develop a simple T 3 solid phase radioimmunoassay, in this paper the immobilization of anti-T 3 antibodies on polystyrene tubes is presented. The best results were obtained with an exposure time of anti-T 3 antibodies (diluted in buffer solution, pH 8.4-8.6) of 40 h at 4 o C. Also, in this study the preparation of 125 I labeled monoclonal antibody (Mab)-anti-TSH is described, which will be used as a component of a TSH-IRMA kit; this kit is to be realized in our department. 125 I - Mab anti-TSH has the following characteristics: specific activity = 20 - 24 μCi/μg and radioactive concentration ≅ 25 μCi/ml; also, the immunological properties of tracer were verified. The major results of this activity is that the total dependence on important kits will be eliminated and also, the costs will be reduced. (authors)

Lower neonatal screening thyroxine concentrations in Down syndrome newborns

NARCIS (Netherlands)

van Trotsenburg, A. S. P.; Vulsma, T.; van Santen, H. M.; Cheung, W.; de Vijlder, J. J. M.

2003-01-01

There is an unexplained higher incidence of congenital hypothyroidism (CH) detected by T-4-based neonatal screening programs and a very high prevalence of (mild) plasma TSH elevation in young children with Down syndrome (DS). To determine whether newborns with DS have decreased blood T-4

Both hypothyroidism and hyperthyroidism increase plasma irisin levels in rats.

Science.gov (United States)

Atici, Emine; Mogulkoc, Rasim; Baltaci, Abdulkerim Kasim; Menevse, Esma

2017-11-28

Background A recently discovered hormone, irisin is accepted to be significantly involved in the regulation of body weight. Thyroid functions may be, directly or indirectly, associated with irisin. Aim The aim of the present study is to determine the effect of experimental thyroid dysfunction on irisin levels in rats. Methods The study registered 40 adult male Sprague-Dawley rats, which were allocated to groups as follows: 1. Control; 2. Hypothyroidism induced by injection of 10 mg/kg/day intraperitoneal propylthiouracil (PTU) for 3 weeks; 3. Hypothyroidism (PTU 2 weeks) + L-thyroxin (1.5 mg/kg/day for 1 week); 4. Hyperthyroidism induced in rats by 3-week thyroxin (0.3 mg/kg/day); 5. Hyperthyroidism + PTU. At the end of the study, blood samples were collected to quantify free triiodothyronine (FT3), free triiodothyronine (FT4) and irisin levels. Results FT3 and FT4 levels were reduced in hypothyroidism and were significantly elevated in hyperthyroidism (p hyperthyroidism groups (p hyperthyroidism, and that when hypothyroidism is corrected by thyroxin administration and hyperthyroidism by PTU injection, plasma irisin values go back to normal.

Development of a simple method for the immobilization of anti-thyroxine antibody on polystyrene tubes for use in the measurement of total thyroxine in serum

International Nuclear Information System (INIS)

Rani Gnanasekar; Shalaka Paradkar; Vijay Kadwad; Ketaki Bapat; Grace Samuel; Sachdev, S.S.; Sivaprasad, N.

2015-01-01

We describe a simple method for the immobilisation of anti-thyroxine antibody on to the surface of polystyrene tubes and a simple assay format for the quantitative estimation of total thyroxine in serum. The immobilisation of anti-thyroxine antibody was achieved through passive adsorption of normal rabbit gamma globulin and anti-rabbit antibody raised in goat, as immune bridges. This procedure ensured minimum utilisation of primary and secondary antibody as neat sera without precipitation or affinity purification. The developed assay system using these antibody coated tubes covers a range of 0-240 ng/mL of thyroxine with intra and inter assay variations of less than 10 %. (author)

Characterization of CD4+ T cell-mediated cytotoxicity in patients with multiple myeloma.

Science.gov (United States)

Zhang, Xiaole; Gao, Lei; Meng, Kai; Han, Chunting; Li, Qiang; Feng, Zhenjun; Chen, Lei

2018-05-01

Multiple myeloma (MM) is an incurable cancer characterized by the development of malignant plasma cells. The CD8 T cell-mediated cytotoxicity is considered a major player in antitumor immunity, but in MM patients, the CD8 T cells displayed senescence markers and were functionally impaired. To investigate whether cytotoxic CD4 T cells could act as a treatment alternative in MM, we examined the frequency and function of naturally occurring cytotoxic CD4 T cells in MM patients. The cytotoxic CD4 T cells were identified as granzyme-A, granzyme B-, and perforin-expressing CD4 T cells, and their frequencies were significantly upregulated in MM patients when compared with healthy controls. The frequencies of cytotoxic CD4 T cells in MM patients were not associated with the frequencies of cytotoxic CD8 T cells, but were negatively associated with disease severity. Interestingly, the expression levels of inhibitory molecules, including PD-1 and CTLA-4, were significantly lower in cytotoxic CD4 T cells than in cytotoxic CD8 T cells. When co-incubated with autologous CD38 + CD138 + plasma cells, CD4 T cells were capable of eliminating plasma cells with varying degrees of efficacy. In MM patients, the frequency of circulating plasma cells was negatively correlated with the frequency of cytotoxic CD4 T cells. Therefore, CD4 T cell-mediated cytotoxicity existed naturally in MM patients and could potentially act as an option in antitumor therapies. Copyright © 2018 Elsevier Inc. All rights reserved.

Cold-increase in brown fat thyroxine 5'-monodeiodinase is attenuated in Zucker obese rat

International Nuclear Information System (INIS)

Wu, S.Y.; Stern, J.S.; Fisher, D.A.; Glick, Z.

1987-01-01

In this study the authors examined the possibility that the reduced brown adipose tissue (BAT) thermogenesis in the Zucker obese rat may result from a limited capacity for enzymic conversion of thyroxine (T 4 ) to triiodothyronine (T 3 ) in BAT. A total of 34 lean and obese rats, ∼4 mo old were divided into three treatment groups: group 1 (5 lean and 6 obese) was fed Purina rat chow for 21 days, and group two (5 lean and 6 obese) was fed a cafeteria diet for 21 days, and groups 3 (6 lean and 6 obese) was fed Purina rat chow and maintained in the cold (8 +/- 1 0 C) for 7 days. Activity of T 4 5'-deiodinase was determined as the rate of T 3 production from added T 4 under controlled in vitro conditions. Serum T 4 and T 3 were determined by radioimmunoassay. The rate of T 4 -to-T 3 conversion in BAT was similar in the lean and obese rats maintained at room temperature, whether fed rat chow or a cafeteria diet. However, expressed per scapular BAT depot, lean rats exposed to cold displayed about a fivefold increase in BAT T 3 production whereas only a small increase was observed in the cold-exposed obese rats. Serum T 3 levels tended to be reduced in the Zucker obese rats. The data indicate a reduced capacity for T 3 production of Zucker rat BAT exposed to cold. This defect may account for the reduced tolerance of the obese animals to cold, but it does not account for their reduced diet-induced BAT thermogenesis

Study on changes of serum lipid profile after withdrawl of levo-thyroxine replacement therapy in patients with radical thyroidectomy for cancer

International Nuclear Information System (INIS)

Yang Shumin; Yu Lili; Dong Lin; Zhu Gaohong; Zhang Jijian

2010-01-01

Objective: To study the changes of serum lipid profile after withdrawl of levo-thyroxine replacement for 4 weeks in patient with radical thyroidectomy for cancer. Methods: Serum thyroid hormones (FT 3 , FT 4 , sTSH, with RIA) levels and lipid profile (Total cholesterol, triglycerides, LDL, HDL, apolipoprotein A-I, apolipoprotein B and Lp (a), with biochemistry) were determined in 46 patients with thyroid carcinoma after operation both during and after 4 weeks' withdrawl of levo-thyroxine replacement treatment. Results: Serum FT 3 , FT 4 levels decreased significantly and serum sTSH, TC, TG, LDL, apo-B, Lp (a) levels increased significantly after 4 weeks' withdrawl of levo-thyroxine replacement (vs during treatment, P 0.05). Conclusion: Hyperlipidaemia did develop in the hypothyroid patients after withdrawl of levo-thyroxine replacement but the degree of which did not not necessarily correlate with the increment of sTSH levels. (authors)

Membrane fusion by VAMP3 and plasma membrane t-SNAREs

International Nuclear Information System (INIS)

Hu Chuan; Hardee, Deborah; Minnear, Fred

2007-01-01

Pairing of SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins on vesicles (v-SNAREs) and SNARE proteins on target membranes (t-SNAREs) mediates intracellular membrane fusion. VAMP3/cellubrevin is a v-SNARE that resides in recycling endosomes and endosome-derived transport vesicles. VAMP3 has been implicated in recycling of transferrin receptors, secretion of α-granules in platelets, and membrane trafficking during cell migration. Using a cell fusion assay, we examined membrane fusion capacity of the ternary complexes formed by VAMP3 and plasma membrane t-SNAREs syntaxin1, syntaxin4, SNAP-23 and SNAP-25. VAMP3 forms fusogenic pairing with t-SNARE complexes syntaxin1/SNAP-25, syntaxin1/SNAP-23 and syntaxin4/SNAP-25, but not with syntaxin4/SNAP-23. Deletion of the N-terminal domain of syntaxin4 enhanced membrane fusion more than two fold, indicating that the N-terminal domain negatively regulates membrane fusion. Differential membrane fusion capacities of the ternary v-/t-SNARE complexes suggest that transport vesicles containing VAMP3 have distinct membrane fusion kinetics with domains of the plasma membrane that present different t-SNARE proteins

Effects of thyroxine and dexamethasone on rat submandibular glands

International Nuclear Information System (INIS)

Sagulin, G.B.; Roomans, G.M.

1989-01-01

Glucocorticoids and thyroxine are known to have a marked effect on the flow rate and protein composition of rat parotid saliva in hormonally intact animals. In the present study, the effects of a one-week treatment of male rats with dexamethasone and thyroxine were studied by electron microscopy and x-ray micro-analysis, and by measurement of the flow rate and determination of the chemical composition of pilocarpine-induced submandibular saliva. Thyroxine had the most extensive effects on the submandibular gland. The acinar cells were enlarged and filled with mucus; the cellular calcium concentration was significantly increased. The flow rate of the submandibular saliva was significantly reduced compared with that in saline-injected control animals. Thyroxine caused an increase in the concentrations of protein, total calcium, and potassium in the saliva. Dexamethasone had no significant effects on gland ultrastructure or on the elemental composition of the acinar cells; flow rate was not affected, but the concentrations of protein, calcium, and potassium were significantly increased. The effects of dexamethasone and thyroxine on the flow rate and protein composition of pilocarpine-induced rat submandibular saliva differ from those reported earlier for rat parotid saliva after simultaneous stimulation with pilocarpine and isoproterenol

Association between l-thyroxine treatment, GH deficiency, and radiological vertebral fractures in patients with adult-onset hypopituitarism.

Science.gov (United States)

Mazziotti, G; Mormando, M; Cristiano, A; Bianchi, A; Porcelli, T; Giampietro, A; Maffezzoni, F; Serra, V; De Marinis, L; Giustina, A

2014-06-01

In this study, we aimed at evaluating the association between radiological vertebral fractures and levo-thyroxine (l-T4) replacement doses in adult patients with hypopituitarism. Cross-sectional study. We studied 74 adult hypopituitary patients (males, 43; females, 31; mean age, 57 years; and range, 23-79) with central hypothyroidism treated with l-T4 (median daily dose: 1.1  μg/kg). All patients also had severe GH deficiency (GHD) and 38 of them were replaced with recombinant GH. Vertebral fractures were assessed by a quantitative morphometric analysis performed on thoracic and lumbar spine lateral X-ray. Radiological vertebral fractures were found in 23 patients (31.1%) in association with untreated GHD (P=0.02), higher serum free T4 levels (P=0.03), a higher daily dose of l-T4 (P=0.005), and a longer duration of hypopituitarism (P=0.05). When GHD was treated, the prevalence of vertebral fractures was more frequent (P=0.03) in patients receiving high l-T4 doses (third tertile: >1.35  μg/kg per day) as compared with patients who were treated with lower drug doses (first tertile: hypopituitarism. © 2014 European Society of Endocrinology.

Rethinking the biological relationships of the thyroid hormones, l-thyroxine and 3,5,3'-triiodothyronine.

Science.gov (United States)

Maher, Stacey K; Wojnarowicz, Pola; Ichu, Taka-Aki; Veldhoen, Nik; Lu, Linghong; Lesperance, Mary; Propper, Catherine R; Helbing, Caren C

2016-06-01

Thyroid hormones (THs), l-thyroxine (T4) and 3,5,3'-triiodothyronine (T3), are essential for vertebrate growth and development. Classically, T4 is 5'-deiodinated to the active hormone, T3, in target tissues which then binds nuclear TH receptors (TRs) and regulates gene transcription. However, it is possible that T4 acts directly on target tissues. Frog metamorphosis is a powerful TR-dependent model for studying TH action. Premetamorphic Rana (Lithobates) catesbeiana tadpoles were injected with 0.1-50 T3 or 0.5-250T4pmol/gbodyweight to account for their 5-fold difference in biological activity and the mRNA profiles in six tissues from well-characterized TH-responsive genes were evaluated after 48h using quantitative real time polymerase chain reaction. 5'-deiodinase-poor tissues should produce superimposable dose-response curves if T4 does not require conversion to T3. This was the case in lung and tail fin; the latter tissue recapitulating these responses in organ culture. 5'-deiodinase-rich tissues should convert T4 to T3. Because T3 has a higher affinity to TRs, a 5-fold higher T4 dose compared to T3 should produce greater transcript induction. This was observed in the brain and for most intestinal transcripts. However, some gene transcripts in the intestine and all transcripts in the back skin produced superimposable response curves suggesting that a direct mode of T4 action is plausible in these tissues. While the liver showed results consistent with its 5'-deiodinase-poor status, we found evidence of an alternate, non-genomic mechanism for two gene transcripts. Therefore, mechanisms not requiring T4 conversion to T3 may play a far greater role than previously thought. Copyright © 2016 Elsevier Inc. All rights reserved.

Hippocampal Neurometabolite Changes in Hypothyroidism: An In Vivo (1) H Magnetic Resonance Spectroscopy Study Before and After Thyroxine Treatment.

Science.gov (United States)

Singh, S; Rana, P; Kumar, P; Shankar, L R; Khushu, S

2016-09-01

The hippocampus is a thyroid hormone receptor-rich region of the brain. A change in thyroid hormone levels may be responsible for an alteration in hippocampal-associated function, such as learning, memory and attention. Neuroimaging studies have shown functional and structural changes in the hippocampus as a result of hypothyroidism. However, the underlying process responsible for this dysfunction remains unclear. Therefore, the present study aimed to investigate the metabolic changes in the brain of adult hypothyroid patients during pre- and post-thyroxine treatment using in vivo proton magnetic resonance spectroscopy ((1) H MRS). (1) H MRS was performed in both healthy control subjects (n = 15) and hypothyroid patients (n = 15) (before and after thyroxine treatment). The relative ratios of the neurometabolites were calculated using the linear combination model (LCModel). Our results revealed a significant decrease of glutamate (Glu) (P = 0.045) and myo-inositol (mI) (P = 0.002) levels in the hippocampus of hypothyroid patients compared to controls. No significant changes in metabolite ratios were observed in the hypothyroid patients after thyroxine treatment. The findings of the present study reveal decreased Glu/tCr and mI/tCr ratios in the hippocampus of hypothyroid patients and these metabolite alterations persisted even after the patients became clinically euthyroid subsequent to thyroxine treatment. © 2016 British Society for Neuroendocrinology.

Thyroxine-induced cardiac hypertrophy: influence of adrenergic nervous system versus renin-angiotensin system on myocyte remodeling.

Science.gov (United States)

Hu, L W; Benvenuti, L A; Liberti, E A; Carneiro-Ramos, M S; Barreto-Chaves, M L M

2003-12-01

The present study assessed the possible involvement of the renin-angiotensin system (RAS) and the sympathetic nervous system (SNS) in thyroxine (T4)-induced cardiac hypertrophy. Hemodynamic parameters, heart weight (HW), ratio of HW to body weight (HW/BW), and myocyte width were evaluated in absence of thyroid hormone (hypothyroidism) and after T4 administration. Male Wistar rats were used. Some were subjected to thyroidectomies, whereas hyperthyroidism was induced in others via daily intraperitoneal injection of T4 (25 or 100 microg x 100 g BW(-1) x day(-1)) for 7 days. In some cases, T4 administration was combined with the angiotensin I-converting enzyme inhibitor enalapril (Ena), with the angiotensin type 1 (AT1) receptor blocker losartan (Los) or with the beta-adrenergic blocker propanolol (Prop). Hemodynamics and morphology were then evaluated. Systolic blood pressure (SBP) was not altered by administration of either T4 alone or T4 in combination with the specific inhibitors. However, SBP decreased significantly in hypothyroid rats. An increased heart rate was seen after administration of either T4 alone or T4 in combination with either Los or Ena. Although the higher dose of T4 significantly increased HW, HW/BW increased in both T4-treated groups. Ena and Prop inhibited the increase in HW or HW/BW in hyperthyroid rats. Morphologically, both T4 dose levels significantly increased myocyte width, an occurrence prevented by RAS or SNS blockers. There was a good correlation between changes in HW/BW and myocyte width. These results indicate that T4-induced cardiac hypertrophy is associated with both the SNS and the RAS.

Measurement of free thyroxine or free 3,5,3'-triiodothyronine in a liquid sample

International Nuclear Information System (INIS)

Hertl, W.; Ward, F.B.; Weetall, H.H.

1982-01-01

An immunoassay method is described for the direct measurement of free thyroxine or 3,5,3'-triiodothyronine in a liquid sample in which the thyroxine or 3,5,3'-triiodothyronine is present in both free and combined states. The sample is combined with a labelled thyroxine- or 3,5,3'-triiodothyronine-horseradish peroxidase conjugate which does not significantly interact with thyroxine-binding globulin, thyroxine-binding prealbumin and immobilised antibody which is specific for thyroxine or 3,5,3'-triiodothyronine. After incubation, the solid phase is separated from the liquid phase and the amount of labelled thyroxine- or 3,5,3'-triiodothyronine-horseradish peroxidase conjugate present in either phase is measured by determining the activity of the label. (author)

Radioimmunossay methods for the determination of L-triiodothyronine and thyroxine

International Nuclear Information System (INIS)

Margherita, S.S.

1978-01-01

An improved, simplified radioimmunoassay method for the in vitro determination of L-triiodothyronine in unextracted blood serum involves the use of a combination reagent constituted by a buffered solution containing radioactive L-triiodothyronine and an inhibitor for inhibiting binding of L-triiodothyronine to thyroxine-binding globulin. Optionally the reagent may also include an antiserum containing antibody capable of immunoreactivity with L-triiodothyronine. Packaged test kits for use in conveniently carrying out the radioimmunoassay are also provided. Certain salts of 8-anilino-1-naphthalene sulfonic acid, which may be regarded as purified forms of the acid, which may be regarded as purified forms of the acid, are preferably employed as inhibitors for inhibiting binding of L-triiodothyronine to thyroxine-binding globulin. An improved radioimmunoassay method for the in vitro determination of thyroxine in unextracted blood serum is characterized by the use of an antiserum containing antibody capable of immunoreactivity with thyroxine and prepared from an immunogen comprising a conjugate of the N-acetyl derivative of thyroxine coupled to bovine serum albumin with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide

Physics of high performance JET plasmas in D-T

International Nuclear Information System (INIS)

2001-01-01

JET has recently operated with deuterium-tritium (D-T) mixtures, carried out an ITER physics campaign in hydrogen, deuterium, D-T and tritium, installed the Mark IIGB ''Gas Box'' divertor fully by remote handling and started physics experiments with this more closed divertor. The D-T experiments set records for fusion power (16.1 MW), ratio of fusion power to plasma input power (0.62, and 0.95±0.17 if a similar plasma could be obtained in steady-state) and fusion duration (4 MW for 4 s). A large scale tritium supply and processing plant, the first of its kind, allowed the repeated use of the 20 g tritium on site to supply 99.3 g of tritium to the machine. The H-mode threshold power is significantly lower in D-T, but the global energy confinement time is practically unchanged (no isotope effect). Dimensionless scaling ''Wind Tunnel'' experiments in D-T extrapolate to ignition with ITER parameters. The scaling is close to gyroBohm, but the mass dependence is not correct. Separating the thermal plasma energy into core and pedestal contributions could resolve this discrepancy (leading to proper gyroBohm scaling for the core) and also account for confinement degradation at high density and at high radiated power. Four radio frequency heating schemes have been tested successfully in D-T, showing good agreement with calculations. Alpha particle heating has been clearly observed and is consistent with classical expectations. Internal transport barriers have been established in optimised magnetic shear discharges for the first time in D-T and steady-state conditions have been approached with simultaneous internal and edge transport barriers. First results with the newly installed Mark IIGB divertor show that the in/out symmetry of the divertor plasma can be modified using differential gas fuelling, that optimised shear discharges can be produced, and that krypton gas puffing is effective in restoring L-mode edge conditions and establishing an internal transport barrier in

Physics of high performance jet plasmas in D-T

International Nuclear Information System (INIS)

1999-01-01

JET has recently operated with deuterium-tritium (D-T) mixtures, carried out an ITER physics campaign in hydrogen, deuterium, D-T and tritium, installed the Mark IIGB 'Gas Box' divertor fully by remote handling and started physics experiments with this more closed divertor. The D-T experiments set records for fusion power (16.1 MW), ratio of fusion power to plasma input power (0.62, and 0.95±0.17 if a similar plasma could be obtained in steady-state) and fusion duration (4 MW for 4 s). A large scale tritium supply and processing plant, the first of its kind, allowed the repeated use of the 20 g tritium on site to supply 99.3 g of tritium to the machine. The H-mode threshold power is significantly lower in D-T, but the global energy confinement time is practically unchanged (no isotope effect). Dimensionless scaling 'Wind Tunnel' experiments in D-T extrapolate to ignition with ITER parameters. The scaling is close to gyroBohm, but the mass dependence is not correct. Separating the thermal plasma energy into core and pedestal contributions could resolve this discrepancy (leading to proper gyroBohm scaling for the core) and also account for confinement degradation at high density and at high radiated power. Four radio frequency heating schemes have been tested successfully in D-T, showing good agreement with calculations. Alpha particle heating has been clearly observed and is consistent with classical expectations. Internal transport barriers have been established in optimised magnetic shear discharges for the first time in D-T and steady-state conditions have been approached with simultaneous internal and edge transport barriers. First results with the newly installed Mark IIGB divertor show that the in/out symmetry of the divertor plasma can be modified using differential gas fuelling, that optimised shear discharges can be produced, and that krypton gas puffing is effective in restoring L-mode edge conditions and establishing an internal transport barrier in such

Utilizing mass spectrometry imaging to map the thyroid hormones triiodothyronine and thyroxine in Xenopus tropicalis tadpoles.

Science.gov (United States)

Goto-Inoue, Naoko; Sato, Tomohiko; Morisasa, Mizuki; Kashiwagi, Akihiko; Kashiwagi, Keiko; Sugiura, Yuki; Sugiyama, Eiji; Suematsu, Makoto; Mori, Tsukasa

2018-02-01

Thyroid hormones are not only responsible for thermogenesis and energy metabolism in animals, but also have an important role in cell differentiation and development. Amphibian metamorphosis provides an excellent model for studying the remodeling of the body. This metamorphic organ remodeling is induced by thyroid hormones, and a larval body is thus converted into an adult one. The matrix-assisted laser desorption/ionization (MALDI)-mass spectrometry (MS) imaging technology is expected to be a suitable tool for investigating small bioreactive molecules. The present study describes the distribution of the thyroid hormones, i.e., triiodothyronine (T3) and thyroxine (T4) and their inactive form reverse T3 (rT3) in Xenopus tropicalis tadpoles using two different types of imaging techniques, MS/MS and Fourier transform (FT)-MS imaging. As a result of MS/MS imaging, we demonstrated that T3 was mainly distributed in the gills. T4 was faintly localized in the eyes, inner gills, and intestine during metamorphosis. The intensity of T3 in the gills and the intensity of T4 in the body fluids were increased during metamorphosis. Moreover, the localization of the inactive form rT3 was demonstrated to be separate from T3, namely in the intestine and muscles. In addition, FT-MS imaging could utilize simultaneous imaging including thyroid hormone. This is the first report to demonstrate the molecular distribution of thyroid hormones themselves and to discriminate T3, T4, and rT3 in animal tissues.

Simultaneous quantification of T4, T3, rT3, 3,5-T2 and 3,3'-T2 in larval zebrafish (Danio rerio) as a model to study exposure to polychlorinated biphenyls.

Science.gov (United States)

Chen, Xiaopeng; Walter, Kyla M; Miller, Galen W; Lein, Pamela J; Puschner, Birgit

2018-06-01

Environmental toxicants that interfere with thyroid hormone (TH) signaling can impact growth and development in animals and humans. Zebrafish represent a model to study chemically induced TH disruption, prompting the need for sensitive detection of THs. Simultaneous quantification of 3,3',5-triiodo-l-thyronine (T3), thyroxine (T4), 3,3',5'-triiodo-l-thyronine (rT3), 3,5-diiodo-l-thyronine (3,5-T2) and 3,3'-diiodo-l-thyronine (3,3'-T2) in zebrafish larvae was achieved by ultra-performance liquid chromatography-tandem mass spectrometry in positive ion mode. Solid-phase extraction with SampliQ cartridges and derivatization with 3 m hydrochloric acid in n-butanol reduced matrix effects. Derivatized compounds were separated on an Acquity UPLC BEH C 18 column with mobile phases consisting of 0.1% acetic acid in deionized water and 0.1% acetic acid in methanol. The limits of detection ranged from 0.5 to 0.6 pg injected on column. The method was validated by evaluating recovery (77.1-117.2%), accuracy (87.3-123.9%) and precision (0.5-12.4%) using diluted homogenized zebrafish embryos spiked with all target compounds. This method was then applied to zebrafish larvae collected after 114 h of exposure to polychlorinated biphenyls (PCBs), including PCB 28, PCB 66 and PCB 95, or the technical mixture Aroclor 1254. Exposure to PCB 28 and PCB 95 increased the T4:T3 ratio and decreased the T3:rT3 ratio, demonstrating that this method can effectively detect PCB-induced alterations in THs. Copyright © 2018 John Wiley & Sons, Ltd.

The Swelling of Rat Liver Mitochondria by Thyroxine and its Reversal

Science.gov (United States)

Lehninger, Albert L.; Ray, Betty Lou; Schneider, Marion

1959-01-01

The in vitro swelling action of L-thyroxine on rat liver mitochondria as examined photometrically represents an acceleration of a process which the mitochondria are already inherently capable of undergoing spontaneously, as indicated by the identical kinetic characteristics and the extent of thyroxine-induced and spontaneous swelling, the nearly identical pH dependence, and the fact that sucrose has a specific inhibitory action on both types of swelling. However, thyroxine does not appear to be a "catalyst" or coenzyme since it does not decrease the temperature coefficient of spontaneous swelling. The temperature coefficient is very high, approximately 6.0 near 20°. Aging of mitochondria at 0° causes loss of thyroxine sensitivity which correlates closely with the loss of bound DPN from the mitochondria, but not with loss of activity of the respiratory chain or with the efficiency of oxidative phosphorylation. Tests with various respiratory chain inhibitors showed that the oxidation state of bound DPN may be a major determinant of thyroxine sensitivity; the oxidation state of the other respiratory carriers does not appear to influence sensitivity to thyroxine. These facts and other considerations suggest that a bound form of mitochondrial DPN is the "target" of the action of thyroxine. The thyroxine-induced swelling is not reversed by increasing the osmolar concentration of external sucrose, but can be "passively" or osmotically reversed by adding the high-particle weight solute polyvinylpyrrolidone. The mitochondrial membrane becomes more permeable to sucrose during the swelling reaction. On the other hand, thyroxine-induced swelling can be "actively" reversed by ATP in a medium of 0.15 M KCl or NaCl but not in a 0.30 M sucrose medium. The action of ATP is specific; ADP, Mn++, and ethylenediaminetetraacetate are not active. It is concluded that sucrose is an inhibitor of the enzymatic relationship between oxidative phosphorylation and the contractility and

The relationship between thyroxine secretion rate and egg production in chicken

International Nuclear Information System (INIS)

Sri Asminah; Soewarsono, M.; Djojosoebagio, S.

1976-01-01

An experiment was carried out in 24 female White Leghorn Chickens by using 131 I as tracer. The chickens were initially and intraperitoneally injected with 10μCi of 131 I and then counted by means of a Gamma Well Type Scintillation Counter every 48 hours. A dose of 0,3 μg of thyroxine per 100 gr body weight was given as the first administration. After every two administrations of similar dose, the dose of the thyroxine was increased by 0,1 μg/100g body weight until the thyroxine secretion rate was reached. The injections were given in the neck region subcutaneously. The thyroxine secretion rate was found to be within the range from 0,5μg to 0,8μg per 100 g body weight. It also showed that the higher the thyroxine secretion rate, the higher the egg production became. This phenomenon occured both with the 7 and 9 months old chickens. However there was neither ralationship between the thyroxine secretion rate and the weight of eggs produced nor with the body weight of the chickens themselves. (author)

Effects of 5,5'-diphenylhydantoin on thyroxine and 3,5,3'-triiodothyronine concentrations in several tissues of the rat

International Nuclear Information System (INIS)

Schroeder-van der Elst, J.Pv.; van der Heide, D.

1990-01-01

We studied the effect of 5,5'-diphenylhydantoin (phenytoin, DPH) on the metabolism of thyroid hormones, the intracellular concentration of T4, and the source and concentration of T3. Two groups of six male Wistar rats received a continuous infusion of 10 ml saline/rat. day. One group received DPH in their food (50 mg/kg BW) for 20 days. For both groups [125I]T4 and [131I]T3 were added to the infusion fluid for the last 10 and 7 days, respectively. At isotopic equilibrium the rats were bled and perfused. Compared to the controls, plasma T4 and T3 in the DPH group were reduced (22% and 31%, respectively); TSH did not change. The rate of production of T4 and the plasma appearance rate for T3 were decreased. Thyroidal T3 production was markedly reduced. From the increased [125I]T3/[125I]T4 ratio for plasma, it follows that total body conversion was enhanced. The tissue T4 concentrations decreased in parallel with the plasma T4 level. Total T3 was reduced in all organs. In tissues in which local conversion does not occur, i.e. heart and muscle, the decrease reflected the decrease in plasma T3. In the liver both plasma-derived T3 and locally produced T3 were diminished. In cerebellum and brain the plasma-derived T3 pool was even smaller than was expected from the decrease in plasma T3. This was partly compensated by an increase in local conversion. Only for these two organs was the decrease in the tissue/plasma ratio for [131I]T3 significant. Our results suggest tissue hypothyroidism, caused by a decrease in the production of T4 and T3, which is partly compensated by increased conversion in several organs. The transport of T3 into cerebellum and brain is disturbed, which can be attributed to the mode of action of DPH

The 24-hour profiles of thyrotropin, throxine and triiodothyronine in goitrous and goitre-free Ugandans

International Nuclear Information System (INIS)

Kajubi, S.K.

1980-01-01

Plasma thyrotropin (TSH), thyroxine (T4) and triiodothyronine (T3) concentrations were measured by radioimmunoassay with commercial assay kits in serial blood samples collected over a 24-hour period from 6 normal and 6 clinically euthyroid but goitrous male Ugandan subjects. Measurements on normal subjects revealed two peaks in plasma TSH concentration, one at about 08.00 hrs, the other at about 20.00 hrs. Plasma T4 concentrations showed two corresponding peaks, while plasma T3 concentrations showed no discernable pattern. Measurement on goitrous subjects revealed only the earlier peak in plasma TSH concentration, while the pooled mean TSH concentration was lower than in normal subjects. Plasma T4 concentrations showed two peaks, as for normal subjects, but the pooled mean T4 concentration was also lower than in normal subjects. Measurements on plasma T3 concentration again showed no discernable pattern. The significance of these findings is discussed

Stavudine (d4T) concentrations in women receiving post-partum antiretroviral treatment and their breastfeeding infants

Science.gov (United States)

Fogel, Jessica M.; Taha, Taha E.; Sun, Jin; Hoover, Donald R.; Parsons, Teresa L.; Kumwenda, Johnstone J.; Mofenson, Lynne M.; Fowler, Mary Glenn; Hendrix, Craig W.; Kumwenda, Newton I.; Eshleman, Susan H.; Mirochnick, Mark

2012-01-01

First-line antiretroviral treatment regimens in resource-limited settings used in breastfeeding mothers often include stavudine (d4T). Limited data describing d4T concentrations in breast milk are available. We analyzed d4T concentrations in 52 mother-infant pairs using ultra-performance liquid chromatography-tandem mass spectrometry (lower limit of quantification: 5 ng/ml in plasma, 20 ng/ml in breast milk). Median (interquartile range) d4T concentrations were 86 (36–191) ng/ml in maternal plasma, 151 (48–259) ng/ml in whole milk, 190 (58–296) ng/ml in skim milk, and <5 (<5-<5) ng/ml in infant plasma. While d4T is concentrated in breast milk relative to maternal plasma, the infant d4T dose received from breast milk is very small and not clinically significant. PMID:22614899

Thyroxine secretion rate during growth in different types of poultry birds

International Nuclear Information System (INIS)

Parshad, Omkar; Gupta, B.K.; Varman, P.N.

1976-01-01

Thyroid activity in pro- and post-pubertal as well as mature poultry birds of egg type i.e. White Leghorn (WLH); dual-purpose i.e. Rhode Island Red (RIR) and meat type i.e. Broiler strain was estimated by determining the thyroxine secretion rate (TSR) using 131 I as a radiotracer at 4 weeks, 14 weeks and 24 weeks of age. The study has revealed that the birds have higher thyroxine secretion rates during pre-pubertal as compared to the post-pubertal period as well as the period around the age of maturity. The birds of Broiler strain have higher TSR as compared to both the pure egg-type and the dual-purpose breeds. (author)

Vanishing large ovarian cyst with thyroxine therapy

OpenAIRE

Dharmshaktu, Pramila; Kutiyal, Aditya; Dhanwal, Dinesh

2013-01-01

Summary A 21-year-old female patient recently diagnosed with severe hypothyroidism was found to have a large ovarian cyst. In view of the large ovarian cyst, she was advised to undergo elective laparotomy in the gynaecology department. She was further evaluated in our medical out-patient department (OPD), and elective surgery was withheld. She was started on thyroxine replacement therapy, and within a period of 4 months, the size of the cyst regressed significantly, thereby improving the cond...

Triiodothyronine and free thyroxine levels are differentially associated with metabolic profile and adiposity-related cardiovascular risk markers in euthyroid middle-aged subjects.

Science.gov (United States)

Roef, Greet L; Rietzschel, Ernst R; Van Daele, Caroline M; Taes, Youri E; De Buyzere, Marc L; Gillebert, Thierry C; Kaufman, Jean-Marc

2014-02-01

We have previously shown that in healthy young men, a less favorable body composition is associated with higher free triiodothyronine (fT3) levels within the euthyroid range. Besides, a higher free-triiodothyronine-to-free-thyroxin (fT3-to-fT4) ratio has been related to a less favorable metabolic phenotype and more placental growth in pregnant women. In the present study, we therefore investigated whether serum thyrotropin (TSH), thyroid hormone levels, and the fT3-to-fT4 ratio are associated with metabolic and adiposity-related cardiovascular risk markers in a healthy population of middle-aged euthyroid men and women. Thyroid parameters were measured in 2524 generally healthy subjects from the Asklepios Study (35-55 years, mean age 46 years). Analyses were restricted to 2315 subjects (1138 women and 1177 men), not using thyroid medication, not having anti-TPO levels above clinical cutoff values or TSH levels outside the reference range (0.27-4.2 mU/L). Twenty-seven percent of the women and 47.5% of the men were overweight, while 13% of women and 17% of men were obese. Twenty percent of the subjects were active smokers. Serum thyroid function parameters were determined by electrochemiluminescence. fT3 and the fT3-to-fT4 ratio were positively related to body mass index (BMI), waist circumference, and components of metabolic syndrome, that is, triglycerides, systolic and diastolic blood pressure, and fasting plasma glucose, and negatively with HDL-cholesterol levels, whereas fT4 was negatively associated with BMI, waist circumference, and triglycerides (p<0.001). TSH related positively with total cholesterol levels (p<0.01), triglycerides, and systolic and diastolic blood pressure (p<0.001). The fT3-to-fT4 ratio was further positively associated with the adiposity-related inflammation markers interleukin-6 and high-sensitivity C-reactive protein and to pulse wave velocity. All associations were adjusted for sex, age, height, and smoking, and most associations

USEFULNESS OF FREE THYROXINE TO FREE TRIIODOTHYRONINE RATIO FOR DIAGNOSTICS OF VARIOUS TYPES OF HYPERTHYROIDISM

Directory of Open Access Journals (Sweden)

Jernej Grmek

2015-06-01

Full Text Available Background: Different types of hyperthyroidism are treated differently. The correct diagnosis enables the adequate treatment. Clinical experiences suggest that free thyroxine (fT4 to free triiodothyronine (fT3 ratio is different for different types of hyperthyroidism. Considering the paucity of literature data on the topic our aim was to evaluate the role of the serum fT4 to fT3 (fT4/fT3ratio in diagnostics of various types of hyperthyroidism.Methods: In retrospective clinical study we included 440 consecutive subjects, examined between February and August 2010, 350 females and 90 males aged between 15 and 97 years, among them 225 healthy subjects (HS, 80 patients with Graves' disease (GD, 48 with toxic adenoma (TA, 61 patients with hyperthyroid Hashimoto’s thyroiditis (HHT, 17 with subacute thyroiditis (ST, and 9 patients with iodine-induced hyperthyroidism (IIH. Thyrotropin (TSH, fT4, fT3 and thyroid autoantibodies were measured. The fT4/fT3 ratio was calculated.Results: The fT4/fT3 ratio was significantly different for various disorders causing hyperthyroidism (p<0.001. Compared with the fT4/fT3 ratio in HS (2.86±0.52, the ratio was significantly higher in HHT and ST (3.27±0.72 and 3.31±0.54, respectively, p<0.001 for both. In GD, the fT4/fT3 ratio was the lowest (2.55±0.58 and in IIH the highest (5.13±1.97. Both ratios significantly differed from the ratio in HS (p<0.001 for both and in other hyperthyroid patients (p<0.001 for both. In patients with TA, the fT4/fT3 ratio was similar as in HS (2.85±0.71 (p=0.085.Conclusion: The fT4/fT3 ratio is different in various types of hyperthyroidism and therefore represents a useful tool in the diagnostic procedure.

Transverse water relaxation in whole blood and erythrocytes at 3T, 7T, 9.4T, 11.7T and 16.4T; determination of intracellular hemoglobin and extracellular albumin relaxivities.

Science.gov (United States)

Grgac, Ksenija; Li, Wenbo; Huang, Alan; Qin, Qin; van Zijl, Peter C M

2017-05-01

Blood is a physiological substance with multiple water compartments, which contain water-binding proteins such as hemoglobin in erythrocytes and albumin in plasma. Knowing the water transverse (R 2 ) relaxation rates from these different blood compartments is a prerequisite for quantifying the blood oxygenation level-dependent (BOLD) effect. Here, we report the Carr-Purcell-Meiboom-Gill (CPMG) based transverse (R 2CPMG ) relaxation rates of water in bovine blood samples circulated in a perfusion system at physiological temperature in order to mimic blood perfusion in humans. R 2CPMG values of blood plasma, lysed packed erythrocytes, lysed plasma/erythrocyte mixtures, and whole blood at 3 T, 7 T, 9.4 T, 11.7 T and 16.4 T were measured as a function of hematocrit or hemoglobin concentration, oxygenation, and CPMG inter-echo spacing (τ cp ). R 2CPMG in lysed cells showed a small τ cp dependence, attributed to the water exchange rate between free and hemoglobin-bound water to be much faster than τ cp . This was contrary to the tangential dependence in whole blood, where a much slower exchange between cells and blood plasma applies. Whole blood data were fitted as a function of τ cp using a general tangential correlation time model applicable for exchange as well as diffusion contributions to R 2CPMG , and the intercept R 20blood at infinitely short τ cp was determined. The R 20blood values at different hematocrit and the R 2CPMG values of lysed erythrocyte/plasma mixtures at different hemoglobin concentration were used to determine the relaxivity of hemoglobin inside the erythrocyte (r 2Hb ) and albumin (r 2Alb ) in plasma. The r 2Hb values obtained from lysed erythrocytes and whole blood were comparable at full oxygenation. However, while r 2Hb determined from lysed cells showed a linear dependence on oxygenation, this dependence became quadratic in whole blood. This possibly suggests an additional relaxation effect inside intact cells, perhaps due to hemoglobin

Serum-thyroxine levels in microwave-exposed rats

International Nuclear Information System (INIS)

Lu, S.T.; Lebda, N.; Michaelson, S.M.; Pettit, S.

1985-01-01

The nature of the response of the thyroid gland in animals exposed to microwave irradiation is controversial. Animal experimentation has contributed to the controversy because both increased and decreased thyroid functions have been reported. The thyroxine concentration in rats as representative of thyroid function in animals exposed to 2.45-GHz, 120-Hz amplitude-modulated microwaves has been studied. These studies covered a long time span; rats from two commercial sources (BS and CR) were used and subjected to different numbers of exposures, and therefore these data were evaluated for their stability. Two factors could influence in the result significantly, i.e., source of animal and number of sham exposures. Rats used in the 2-hr exposures were from two different commercial sources; rats from CR had a higher (but normal) thyroxine concentration than did rats from BS. Therefore the data of these animals were separated by commercial source for reevaluation. Instead of increased thyroxine concentration in rats exposed at 25, 30, and 40 mW/cm 2 , changes were not noted in any microwave-exposed rats. The influence of sham exposure revealed that appropriate concurrent control and specification of animal source are needed in longitudinal studies. Furthermore, statistical procedures used can greatly influence the conclusions. Thus the specificity of changes in thyroxine concentration in rats exposed to microwaves because of its sporadic occurrence and because of inconsistencies among experiments was doubted

A simple unifying procedure for radioimmunoassay of thyroxine, triiodothyronine and reverse triiodothyronine in unextracted serum

International Nuclear Information System (INIS)

Slebodzinski, A.B.; Nowak, G.; Zamyslowska, H.

1980-01-01

A simple unifying procedure for radioimmunoassay (RIA) of thyroxine, T 4 , triiodothyronine, T 3 , and reverse-triiodothyronine, rT 3 , in unextracted serum has been developed. In the method 8-anilino-naphthalene sulfonic acid, sodium salicylate and barbital were used as inhibitors of iodothyronine binding to proteins of serum and charcoal for separation of antibody-bound and free hormone fractions. For statistical evaluation and quality control of the results the assay data were analyzed after logit/log transformation. In this way, a reasonable linearization of the standard curve was achieved. The lower limit of detection of T 4 was 35 pg and for triiodothyronine (T 3 plus rT 3 ) 7.5 pg. The intraassay variability averaged from 5-7%. Corresponding betweenassay coefficient of variation was from 11-13%. The recovery of added hormone to the hormone-free serum was near 100%, and the index of precision (lambda) below 0.1. The useable range of hormone determination was found to be from 0.5 μg to 15 μg T 4 and from 15 to 200 ng T 3 or rT 3 per dl serum. Using this unifying procedure one person can perform about 120 determinations per day. After logit/log transformation of the input data and linearization of the standard curve, the statistical analysis and data processing can be easily performed by a suitable RIA programme for a top desk calculator. (author)

Effects of Aroclor 1242 and different fish-based diets on vitamins A(retinol) and A2 (3,4-didehydroretinol), and their fatty acyl esters in mink plasma

International Nuclear Information System (INIS)

Kaekelae, Anne; Kaekelae, Reijo; Hyvaerinen Heikki; Nieminen, Petteri

2003-01-01

The effects of a 21-week exposure to Aroclor 1242 (1 mg per day in feed on plasma concentrations of vitamins A 1 (retinol) and A(3,4-didehydroretinol) and their principal fatty acyl esters (A 1 -16:0 A 2 -16:0 (palmitates), A 1 -18:1n-9; A 2 -18:1n-9 (oleates), and A 1 -18:0 A 2 -18:0 (stearates)) were studied in young female mink (Mustela vison) fed a diet based on freshwater smelt. These vitamin levels were also examined in mink fed diets containing Baltic herring or fatty marine fish. In the Aroclor-exposed smelt-fed mink, the plasma concentrations of A 1 and Aesters were significantly lower than the levels in controls fed the uncontaminated smelt diet. In addition, the A 2 esters reacted mor sensitively to the polychlorinated biphenyls than did A 1 esters. I contrast, in the plasma of the exposed mink the level of alcoholic A 1 was normal, and transport of thyroxine (T 4 ) and nonspecific lipoprotei transport of major lipids were not impaired. Despite the large dietary supply of vitamin A 2 and high levels of plasma A 2 esters, the mink fed freshwate smelt had only trace amounts of alcoholic vitamin A 2 in their plasma. The concentrations of A 1 and A 2 esters in the plasma of all the mink studied correlated with the hepatic total concentrations of the vitamins. Thus, in carnivores that have nonspecific lipoprotein transport of vitamin A esters determination of plasma levels of the esterified vitamins may be a useful nondestructive way to estimate stores of the vitamin A analogs in the body and to assess the organochlorine-induced decrease in the vitamin stores

Higher Thyroid-Stimulating Hormone, Triiodothyronine and Thyroxine Values Are Associated with Better Outcome in Acute Liver Failure.

Science.gov (United States)

Anastasiou, Olympia; Sydor, Svenja; Sowa, Jan-Peter; Manka, Paul; Katsounas, Antonios; Syn, Wing-Kin; Führer, Dagmar; Gieseler, Robert K; Bechmann, Lars P; Gerken, Guido; Moeller, Lars C; Canbay, Ali

2015-01-01

Changes in thyroid hormone levels, mostly as non-thyroidal illness syndrome (NTIS), have been described in many diseases. However, the relationship between acute liver failure (ALF) and thyroid hormone levels has not yet been clarified. The present study evaluates potential correlations of select thyroid functional parameters with ALF. 84 consecutively recruited ALF patients were grouped according to the outcome of ALF (spontaneous recovery: SR; transplantation or death: NSR). TSH, free thyroxine (fT4), free triiodothyronine (fT3), T4, and T3 were determined. More than 50% of patients with ALF presented with abnormal thyroid parameters. These patients had greater risk for an adverse outcome than euthyroid patients. SR patients had significantly higher TSH, T4, and T3 concentrations than NSR patients. Albumin concentrations were significantly higher in SR than in NSR. In vitro T3 treatment was not able to rescue primary human hepatocytes from acetaminophen induced changes in mRNA expression. In patients with ALF, TSH and total thyroid hormone levels differed significantly between SR patients and NSR patients. This might be related to diminished liver-derived transport proteins, such as albumin, in more severe forms of ALF. Thyroid parameters may serve as additional indicators of ALF severity.

Quantification of thyroxine by the selective photoluminescence quenching of L-cysteine–ZnS quantum dots in aqueous solution containing hexadecyltrimethylammonium bromide

International Nuclear Information System (INIS)

Khan, Sarzamin; Carneiro, Leonardo S.A.; Romani, Eric C.; Larrudé, Dunieskys G.; Aucelio, Ricardo Q.

2014-01-01

The determination of L-thyroxine is proposed based on the photoluminescence quenching effect caused on the L-cysteine modified ZnS quantum dots (L-cysteine ZnS QDs) aqueous dispersion. Under optimum conditions, the analytical response followed a Stern–Volmer model and the experimental conditions were adjusted to enable a robust and reproducible photoluminescence signal. The linear response observed in the quantum dots aqueous dispersion covered the L-thyroxine concentration from the LOQ (2.0×10 −8 mol L −1 ) to 4.0×10 −6 mol L −1 . The approach was tested in the determination of L-thyroxine in pharmaceutical formulations used to treat patients with thyroid gland disorder. The percent recoveries in controlled samples were between 93.3 and 103%. Analyte fortified saliva was also evaluated as a possible sample for L-thyroxine monitoring of a patient under treatment. It was identified a static type of photoluminescence quenching caused by L-thyroxine. - Highlights: • L-cysteine ZnS QDs were used as a photoluminescent probe to detect L-thyroxine. • Intensity of probe decreases following a Stern–Volmer model. • The method can detect down ng L −1 levels of L-thyroxine in the probe dispersion. • Method was used to determinate of L-thyroxine in saliva and in pharmaceuticals. • Mechanism of interaction between L-thyroxine and quantum dots was studied

The metabolic consequences of thyroxine replacement in adult hypopituitary patients

DEFF Research Database (Denmark)

Filipsson Nyström, Helena; Feldt-Rasmussen, Ulla; Kourides, Ione

2012-01-01

The metabolic consequences of thyroxine replacement in patients with central hypothyroidism (CH) need to be evaluated. The aim was to examine the outcome of thyroxine replacement in CH. Adult hypopituitary patients (n = 1595) with and without CH from KIMS (Pfizer International Metabolic Database...

Thyroid Function Test in Thyroid Diseases and Pregnancy - The diagnostic value of free thyroxine by RIA -

International Nuclear Information System (INIS)

Yoo, M. H.; Yoon, H. J.; Shin, Y. T.; Lee, J. C.; Chung, S. I.; Cho, B. Y.; Lee, M. H.; Lee, M. C.

1981-01-01

To evaluate the diagnostic accuracy of the measurement of free thyroxine(FT4) by radioimmunoassay, we measured free T 4 and T 4 , T 3 , T 3 RU, TSH and TBG serum levels by radioimmunoassay in 18 healthy persons and 52 patients with various thyroid diseases and 11 normal pregnant women. The results are as follows. 1) In 19 cases of overt hyperthyroidism, T 3 , free T 4 and FTI, T 4 /TBG ratio reflect hyperfunction in all cases. T 4 is increased in 94%(18/19) and TBG and TSH are decreased in 79%(15/19). 2) In 8 patients with overt hypothyroidism, TSH is increased in all cases and free T 4 and FTI is decreased in all cases. T 4 is decreased in 87.5%(7/8), T 3 is decreased in 75%(6/8) and T 4 /TBG ratio is decreased in 62.5%(5/8). 3) In 5 patients who are clinically in euthyroid state after treatment of hyperthyroidism, T , 4 free T 4 , FTI and TSH are in the normal range in all cases and T 3 is normal in 60%(3/5) and slightly increased in 40%(2/5). 4) In 10 patients who showed clinically borderline hypothyroidism after treatment of hyperthyroidism, TSH is increased in all cases and free T 4 and FTI are decreased in all cases, but T 4 and T 3 , T 4 /TBG ratio are in the normal limit in all cases. So after treatment of hyperthyroidism, TSH, free T 4 or FTI are recommended as optimal function test. 5) In normal pregnancy, free T 4 , FTI and T 4 /TBG ratio reflect normal function, but the other parameters unreliable due to the influence of increased TBG. Also TBG and TSH level in pregnancy is increased significantly compared with normal healthy control group. 6) The coefficients of correlation between T 4 and FTI were 0.862(p 4 and T 4 /TBG ratio. In most patients, diagnostic value of free T 4 was comparable and even superior to FTI, so free T 4 measurement can be used routinely with thyrotropin assay in the diagnosis of hypothyroidism or with T 3 for the diagnosis of hyperthyroidism.

Cathepsin C and plasma glutamate carboxypeptidase secreted from Fischer rat thyroid cells liberate thyroxin from the N-terminus of thyroglobulin.

Science.gov (United States)

Suban, Dejan; Zajc, Tajana; Renko, Miha; Turk, Boris; Turk, Vito; Dolenc, Iztok

2012-03-01

The release of a thyroid hormone from thyroglobulin is controlled by a complex regulatory system. We focused on the extracellular action of two lysosomal enzymes, cathepsin C (catC, dipeptidyl peptidase I) and PGCP (lysosomal dipeptidase), on thyroglobulin, and their ability to liberate the hormone thyroxin. Cathepsin C, an exopeptidase, removes dipeptides from the N-terminus of substrates, and PGCP hydrolyses dipeptides to amino acids. In vitro experiments proved that cathepsin C removes up to 12 amino acids from the N-terminus of porcine thyroglobulin, including a dipeptide with thyroxin on position 5. The newly formed N-terminus, Arg-Pro-, was not hydrolysed further by cathepsin C. Cell culture experiments with FRTL-5 cell line showed localization of cathepsin C and PGCP and their secretion into the medium. Secretion of the active cathepsin C from FRTL-5 cells is stimulated by TSH, insulin, and/or somatostatin. The released enzymes liberate thyroxin from porcine thyroglobulin added to media. The hormone liberation can be reduced by synthetic inhibitors of cysteine proteinases and metalloproteinases. Additionally, we show that TSH, insulin, and/or somatostatin induce up-regulation of N-acetylglucosaminyltransferase 1, the enzyme responsible for the initiation of biosynthesis of hybrid and complex N-glycosylation of proteins. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

HUBUNGAN KADAR TIROGLOBULIN, TSH DAN fT4 SERUM PADA ANAK USIA SEKOLAH DI TIGA KABUPATEN DENGAN TINGKAT ENDEMISITAS DEFISIENSI-IODIUM BERBEDA (ASSOCIATION BETWEEN THE SERUM THYROGLOBULIN, TSH, AND fT4 AMONG SCHOOL-AGED CHILDREN IN THREE DISTRICTS WITH DIF

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Agus Wibowo

2013-06-01

Full Text Available ABSTRACT Iodine deficiency lowers circulating thyroxine (T4 and raises serum Thyroid Stimulating Hormone (TSH, where free T4 (fT4 and TSH have strong corelation with thyroglobulin (Tg. The results from population studies indicate, Tg appears to be a valuable indicator of thyroid status, but it has yet to be fully explored. This study aimed to measure the association between serum Tg with TSH and fT4 as alternatif indicators thyroid status in school-aged children. This was a cross-sectional study of sample of 398 schoolchildren aged 10-12 years in three districts with different iodine-deficiency endemicity level, i.e. Pati as a mild endemic district, Purbalingga as a moderate endemic district, and Malang as a severe endemic district. Children’s blood have taken 3 cc as a sample for the determination of Tg, TSH, and fT4. Enzyme-Linked Immunosorbent Assay (ELISA was used to determine Tg, TSH and fT4. Mean of serum Tg 14.3 ± 11.1 ng/mL (cut-off 2-50 ng/mL, TSH 3.7 ± 2.2 µIU/mL (cut-off 0.3-6.2, fT4 1.4 ± 0.4 ng/dL (cut-off 0.8-2.0 ng/dL. Correlation analysis was showed the significance of Tg and TSH (p< 0.05 and Tg with fT4 (p< 0.05. The significance analysis of Tg with TSH and fT4 may be evaluated as indicator  for thyroid function in school-aged children in iodine-deficiency endemic areas.   Keywords: thyroglobulin (Tg, Thyroid Stimulating Hormone (TSH, free thyroxine (fT4, school-aged children ABSTRAK Defisiensi iodium menurunkan tiroksin (T4 yang beredar dalam darah dan meningkatkan Thyroid Stimulating Hormone (TSH, di mana T4 bebas (fT4 dan TSH memiliki hubungan erat dengan tiroglobulin (Tg. Hasil studi populasi menunjukkan, Tg tampak menjadi indikator berharga untuk status tiroid di daerah endemik defisiensi iodium, tetapi belum sepenuhnya dieksplorasi. Penelitian ini bertujuan mengukur hubungan antara kadar Tg serum dengan kadar TSH dan fT4 sebagai indikator alternatif status tiroid pada anak usia sekolah. Ini merupakan penelitian

Oral fluid and plasma 3,4-methylenedioxymethamphetamine (MDMA) and metabolite correlation after controlled oral MDMA administration.

Science.gov (United States)

Desrosiers, Nathalie A; Barnes, Allan J; Hartman, Rebecca L; Scheidweiler, Karl B; Kolbrich-Spargo, Erin A; Gorelick, David A; Goodwin, Robert S; Huestis, Marilyn A

2013-05-01

Oral fluid (OF) offers a noninvasive sample collection for drug testing. However, 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) in OF has not been adequately characterized in comparison to plasma. We administered oral low-dose (1.0 mg/kg) and high-dose (1.6 mg/kg) MDMA to 26 participants and collected simultaneous OF and plasma specimens for up to 143 h after dosing. We compared OF/plasma (OF/P) ratios, time of initial detection (t first), maximal concentrations (C max), time of peak concentrations (t max), time of last detection (t last), clearance, and 3,4-methylenedioxyamphetamine (MDA)-to-MDMA ratios over time. For OF MDMA and MDA, C max was higher, t last was later, and clearance was slower compared to plasma. For OF MDA only, t first was later compared to plasma. Median (range) OF/P ratios were 5.6 (0.1-52.3) for MDMA and 3.7 (0.7-24.3) for MDA. OF and plasma concentrations were weakly but significantly correlated (MDMA: R(2) = 0.438, MDA: R(2) = 0.197, p MDMA low = 5.2 (0.1-40.4), high = 6.0 (0.4-52.3, p MDMA ratios in plasma were higher than those in OF (p MDMA ratios significantly increased over time in OF and plasma. The MDMA and MDA concentrations were higher in OF than in plasma. OF and plasma concentrations were correlated, but large inter-subject variability precludes the estimation of plasma concentrations from OF.

Quantification of thyroxine by the selective photoluminescence quenching of L-cysteine–ZnS quantum dots in aqueous solution containing hexadecyltrimethylammonium bromide

Energy Technology Data Exchange (ETDEWEB)

Khan, Sarzamin; Carneiro, Leonardo S.A. [Chemistry Department, Pontifícia Universidade Católica do Rio de Janeiro, 22451-900 Rio de Janeiro-RJ (Brazil); Romani, Eric C.; Larrudé, Dunieskys G. [Physics Department, Pontifícia Universidade Católica do Rio de Janeiro, 22451-900, Rio de Janeiro-RJ (Brazil); Aucelio, Ricardo Q., E-mail: aucelior@puc-rio.br [Chemistry Department, Pontifícia Universidade Católica do Rio de Janeiro, 22451-900 Rio de Janeiro-RJ (Brazil)

2014-12-15

The determination of L-thyroxine is proposed based on the photoluminescence quenching effect caused on the L-cysteine modified ZnS quantum dots (L-cysteine ZnS QDs) aqueous dispersion. Under optimum conditions, the analytical response followed a Stern–Volmer model and the experimental conditions were adjusted to enable a robust and reproducible photoluminescence signal. The linear response observed in the quantum dots aqueous dispersion covered the L-thyroxine concentration from the LOQ (2.0×10{sup −8} mol L{sup −1}) to 4.0×10{sup −6} mol L{sup −1}. The approach was tested in the determination of L-thyroxine in pharmaceutical formulations used to treat patients with thyroid gland disorder. The percent recoveries in controlled samples were between 93.3 and 103%. Analyte fortified saliva was also evaluated as a possible sample for L-thyroxine monitoring of a patient under treatment. It was identified a static type of photoluminescence quenching caused by L-thyroxine. - Highlights: • L-cysteine ZnS QDs were used as a photoluminescent probe to detect L-thyroxine. • Intensity of probe decreases following a Stern–Volmer model. • The method can detect down ng L{sup −1} levels of L-thyroxine in the probe dispersion. • Method was used to determinate of L-thyroxine in saliva and in pharmaceuticals. • Mechanism of interaction between L-thyroxine and quantum dots was studied.

Alteration of Hemostatic Parameters in Patients with Different Levels of Subclinical Hypothyroidism and the Effect of L-thyroxine Treatment.

Science.gov (United States)

Gao, Fang; Wang, Guangya; Xu, Jinxiu

2017-01-01

Subclinical hypothyroidism (SH) is associated with hypercoagulability and hypofibrinolysis. The objective of this study was to assess the effect of L-thyroxine (L-T4) treatment and to evaluate changes in the hemostatic abnormalities of patients with varying severities of SH. We measured tissue plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1), D-dimer (DDI), fibrinogen (FIB), platelet counts (PLT), mean platelet volume (MPV), platelet distribution width (PDW), activated partial thromboplastin time (APTT), and prothrombin time (PT) in 149 female subjects. The prospective study included 54 patients in the control group, 53 patients with 4.2 μIU/mLtreatment, a significant decrease in FIB, PAI-1 and t-PA levels and an increase in APTT and DDI were observed in the severe SH group. In conclusion, SH patients displayed a distinct pattern of alteration of hemostatic parameters that was dependent on the severity of the disease. Patients with TSH levels ≥10 μIU/mL displayed hypercoagulability, which was reversed by 6 months of L-T4 treatment. © 2017 by the Association of Clinical Scientists, Inc.

Experimental study of tungsten transport properties in T-10 plasma

Science.gov (United States)

Krupin, V. A.; Nurgaliev, M. R.; Klyuchnikov, L. A.; Nemets, A. R.; Zemtsov, I. A.; Dnestrovskij, A. Yu.; Sarychev, D. V.; Lisitsa, V. S.; Shurygin, V. A.; Leontiev, D. S.; Borschegovskij, A. A.; Grashin, S. A.; Ryjakov, D. V.; Sergeev, D. S.; Mustafin, N. A.; Trukhin, V. M.; Solomatin, R. Yu.; Tugarinov, S. N.; Naumenko, N. N.

2017-06-01

First experimental results of tungsten transport investigation in OH and ECRH plasmas in the T-10 tokamak with W-limiter and movable Li-limiter are presented. It is shown that tungsten tends to accumulate (a joint process of cumulation and peaking) near the plasma axis in ohmic regimes. The cumulation of W is enhanced in discharges with high values of the parameter γ ={{\\bar{n}}\\text{e}}\\centerdot {{\\bar{Z}}\\text{eff}}\\centerdot I\\text{pl}-1.5 that coincides with accumulation conditions of light and medium impurities in T-10 plasmas. Experiments with Li-limiter show the immeasurable level of Li3+ (0.3-0.5% of n e) of T-10 CXRS diagnostics because of the low inflow of Li with respect to other light impurities. Nevertheless, the strong influence of lithium on inflow of light and tungsten impurities is observed. In discharges with lithized walls, vanishing of light impurities occurs and values of {{Z}\\text{eff}}≈ 1 are obtained. It is also shown that the tungsten density in the plasma center decreases by 15 to 20 times while the W inflow reduces only by 2 to 4 times. In lithized discharges with high γ, the flattening of the tungsten density profile occurs and its central concentration decreases up to 10 times during the on-axis ECRH. This effect is observed together with the increase of the W inflow by 3 to 4 times at the ECRH stage.

Effects of 5,5'-diphenylhydantoin on thyroxine and 3,5,3'-triiodothyronine concentrations in several tissues of the rat

Energy Technology Data Exchange (ETDEWEB)

Schroeder-van der Elst, J.Pv.; van der Heide, D. (University Hospital, Leiden (Netherlands))

1990-01-01

We studied the effect of 5,5'-diphenylhydantoin (phenytoin, DPH) on the metabolism of thyroid hormones, the intracellular concentration of T4, and the source and concentration of T3. Two groups of six male Wistar rats received a continuous infusion of 10 ml saline/rat. day. One group received DPH in their food (50 mg/kg BW) for 20 days. For both groups (125I)T4 and (131I)T3 were added to the infusion fluid for the last 10 and 7 days, respectively. At isotopic equilibrium the rats were bled and perfused. Compared to the controls, plasma T4 and T3 in the DPH group were reduced (22% and 31%, respectively); TSH did not change. The rate of production of T4 and the plasma appearance rate for T3 were decreased. Thyroidal T3 production was markedly reduced. From the increased (125I)T3/(125I)T4 ratio for plasma, it follows that total body conversion was enhanced. The tissue T4 concentrations decreased in parallel with the plasma T4 level. Total T3 was reduced in all organs. In tissues in which local conversion does not occur, i.e. heart and muscle, the decrease reflected the decrease in plasma T3. In the liver both plasma-derived T3 and locally produced T3 were diminished. In cerebellum and brain the plasma-derived T3 pool was even smaller than was expected from the decrease in plasma T3. This was partly compensated by an increase in local conversion. Only for these two organs was the decrease in the tissue/plasma ratio for (131I)T3 significant. Our results suggest tissue hypothyroidism, caused by a decrease in the production of T4 and T3, which is partly compensated by increased conversion in several organs. The transport of T3 into cerebellum and brain is disturbed, which can be attributed to the mode of action of DPH.

Effects of obesity, total fasting and re-alimentation on L-thyroxine (T4), 3,5,3'-L-triiodothyronine (T3), 3,3',5'-L-triiodothyronine (rT3), thyroxine binding globulin (TBG), cortisol, thyrotrophin, cortisol binding globulin (CBG), transferrin, alpha 2-haptoglobin and complement C'3 in serum.

Science.gov (United States)

Scriba, P C; Bauer, M; Emmert, D; Fateh-Moghadam, A; Hofmann, G G; Horn, K; Pickardt, C R

1979-08-01

The effects of total fasting for 31 +/- 10 days followed by re-alimentation with an 800 calorie diet on thyroid function, i.e. T4,T3,rT3,RT3U (resin T3 uptake), and TSH, and on TBG levels in serum were studied sequentially in obese hospitalized patients (N=18). Additionally, cortisol, growth hormone, prolactin, parathyrin and free fatty acids were followed as hormonal and metabolic parameters, respectively. Further, CBG, transferrin, alpha 2-haptoglobin and complement C'3 were measured as representatives of other serum proteins. Results before fasting: T4, T3, TBG, cortisol, CBG, alpha 2-haptoglobin and complement C'3 of the obese patients were elevated when compared with healthy normal weight controls, whereas rT3, T4/TBG ratio, T3/TBG ratio, TSH, coritsol/cbg ratio, growth hormone, prolactin, parathyrin and transferrin of the obese group were normal. RT3U and fT4 index were decreased in the obese patients. Results during fasting: Significant decreases were observed during fasting for the following parameters -- T3, TBG, T3/TBG ratio, transferrin, alpha 2-haptoglobin complement C'3. rT3, T4/TBG ratio, RT3U, fT4 index and FFA increased. T4, tsh response to TRH stimulation, cortisol, CBG, cortisol/cbg ratio, parathyrin, growth hormone and prolactin did not change. Results during re-alimentation: T3, TBG, T3/TBG ratio, TSH response to TRH, transferrin, alpha 2-haptoglobin and complement C'3 increased. Conversely, fT3, RT3U, FFA, cortisol and cortisol/cbg ratio decreased whereas the other parameters did not change. 1) There is no evidence for primary hypothyroidism in obese patients during prolonged fasting and re-alimentation. 2) The rapid decrease of T3 and increase of RT3U after initiation of fasting are not fully explained by the observed slower decreases in TBG. 3) The alterations of T3, rT3 and RT3U resemble in their kinetics the changes in FFA levels. 4) Fasting reduced the levels of only certain serum proteins, interestingly TBG, transferrin, alpha 2

Effects of T3 treatment on brown adipose tissue and energy expenditure in a patient with craniopharyngioma and hypothalamic obesity.

Science.gov (United States)

van Santen, Hanneke M; Schouten-Meeteren, Antoinette Y; Serlie, Mireille; Meijneke, Ruud W H; van Trotsenburg, A S; Verberne, Hein; Holleman, Frits; Fliers, Eric

2015-01-01

Patients treated for childhood craniopharyngioma often develop hypothalamic obesity (HO), which has a huge impact on the physical condition and quality of life of these patients. Treatment for HO thus far has been disappointing, and although several different strategies have been attempted, all interventions had only transient effects. Since thyroid hormones increase energy expenditure metabolism (thyroid hormone induced thermogenesis), it was speculated that treatment with tri-iodothyronine (T3) may be beneficial. In 2002, a case report was published on reduction of body weight after T3 treatment for HO. No studies have been reported since. Recent experimental studies in rodents showed that T3 increases brown adipose tissue (BAT) activity via (pre)sympathetic pathways between the hypothalamus and BAT. Our aim was to investigate whether T3 treatment increases BAT activity in a patient with HO resulting from (treatment of) childhood craniopharyngioma. Thyroxine treatment for central hypothyroidism was switched to T3 monotherapy. Serum T3 and free thyroxine (FT4) concentrations were measured twice weekly for 2 months. ¹²³I-MIBG and ¹⁸F-FDG-PET after induction of non-shivering thermogenesis for the assessment of sympathetic and metabolic activity of BAT as well as indirect calorimetry for assessment of resting energy expenditure were performed before and during T3 treatment. No change in sympathetic and metabolic BAT activity, energy expenditure, or BMI was seen during T3 treatment despite the expected changes in thyroid hormone plasma concentrations. We conclude that T3 monotherapy does not seem to be effective in decreasing HO in childhood craniopharyngioma.

Mercury exposure associated with altered plasma thyroid hormones in the declining western pond turtle (Emys marmorata) from California mountain streams

Science.gov (United States)

Meyer, Erik; Eagles-Smith, Collin A.; Sparling, Donald; Blumenshine, Steve

2014-01-01

Mercury (Hg) is a global threat to wildlife health that can impair many physiological processes. Mercury has well-documented endocrine activity; however, little work on the effects of Hg on the thyroid hormones triiodothyronine (T3) and thyroxine (T4) in aquatic wildlife exists despite the fact that it is a sensitive endpoint of contaminant exposure. An emerging body of evidence points to the toxicological susceptibility of aquatic reptiles to Hg exposure. We examined the endocrine disrupting potential of Hg in the western pond turtle (Emys marmorata), a long-lived reptile that is in decline throughout California and the Pacific Northwest. We measured total Hg (THg) concentrations in red blood cells (RBCs) and plasma T3 and T4 of turtles from several locations in California that have been impacted by historic gold mining. Across all turtles from all sites, the geometric mean and standard error THg concentration was 0.805 ± 0.025 μg/g dry weight. Sampling region and mass were the strongest determinants of RBC THg. Relationships between RBC THg and T3 and T4 were consistent with Hg-induced disruption of T4 deiodination, a mechanism of toxicity that may cause excess T4 levels and depressed concentrations of biologically active T3.

Mercury exposure associated with altered plasma thyroid hormones in the declining western pond turtle (Emys marmorata) from California mountain streams.

Science.gov (United States)

Meyer, Erik; Eagles-Smith, Collin A; Sparling, Donald; Blumenshine, Steve

2014-01-01

Mercury (Hg) is a global threat to wildlife health that can impair many physiological processes. Mercury has well-documented endocrine activity; however, little work on the effects of Hg on the thyroid hormones triiodothyronine (T3) and thyroxine (T4) in aquatic wildlife exists despite the fact that it is a sensitive endpoint of contaminant exposure. An emerging body of evidence points to the toxicological susceptibility of aquatic reptiles to Hg exposure. We examined the endocrine disrupting potential of Hg in the western pond turtle (Emys marmorata), a long-lived reptile that is in decline throughout California and the Pacific Northwest. We measured total Hg (THg) concentrations in red blood cells (RBCs) and plasma T3 and T4 of turtles from several locations in California that have been impacted by historic gold mining. Across all turtles from all sites, the geometric mean and standard error THg concentration was 0.805 ± 0.025 μg/g dry weight. Sampling region and mass were the strongest determinants of RBC THg. Relationships between RBC THg and T3 and T4 were consistent with Hg-induced disruption of T4 deiodination, a mechanism of toxicity that may cause excess T4 levels and depressed concentrations of biologically active T3.

Effect of Thyroxin Treatment on Carotid Intima-Media Thickness (CIMT) Reduction in Patients with Subclinical Hypothyroidism (SCH): a Meta-Analysis of Clinical Trials.

Science.gov (United States)

Aziz, Muhammad; Kandimalla, Yugandhar; Machavarapu, Archana; Saxena, Anshul; Das, Sankalp; Younus, Adnan; Nguyen, Michelle; Malik, Rehan; Anugula, Dixitha; Latif, Muhammad A; Humayun, Choudhry; Khan, Idrees M; Adus, Ali; Rasool, Aisha; Veledar, Emir; Nasir, Khurram

2017-07-01

Research shows that subclinical hypothyroidism (SCH) is related to an increased carotid intima-media thickness (CIMT), a surrogate marker of subclinical cardiovascular disease (CVD). It is controversial whether or not SCH should be treated to reduce CVD morbidity and mortality. This meta-analysis aimed to determine whether SCH is associated with an increase in CIMT as compared to Euthyroidism (EU) and whether thyroxin (T4) treatment in SCH can reverse the change in CIMT. Two independent reviewers conducted an extensive database research up to December 2016. A total of 12 clinical trials discussed the effect of Thyroxin on CIMT values at pre- and post-treatment in subjects with SCH. CIMT was significantly higher among SCH (n=280) as compared to EU controls (n=263) at baseline; the pooled weighted mean difference (WMD) of CIMT was 0.44 mm [95% confidence interval (CI) 0.14, 0.74], p=0.004; I 2 =65%. After treatment with thyroxin in subjects with SCH (n=314), there was a statistically significant decrease in CIMT from pre- to post-treatment; the pooled WMD of CIMT decrease was [WMD －0.32; 95% CI (－0.47, －0.16), p=＜0.0001; I 2 =2%], and it was no longer different from EU controls [WMD 0.13 mm; 95% CI (－0.04, 0.30); p=0.14; I 2 =27%]. The total cholesterol (TC), triglycerides (TG), and low-density lipoprotein (LDL) were higher in SCH as compared to EU controls and decreased significantly after treatment with thyroxin. This meta-analysis shows that thyroxin therapy in subjects with SCH significantly decreases CIMT and improves lipid profile, modifiable CVD risk factors. Thyroid hormone replacement in subjects with SCH may play a role in slowing down or preventing the progression of atherosclerosis.

Increased Bone Marrow (BM) Plasma Level of Soluble CD30 and Correlations with BM Plasma Level of Interferon (IFN)-γ, CD4/CD8 T-Cell Ratio and Disease Severity in Aplastic Anemia

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Shi, Jun; Ge, Meili; Li, Xingxin; Shao, Yingqi; Yao, Jianfeng; Zheng, Yizhou

2014-01-01

Idiopathic aplastic anemia (AA) is an immune-mediated bone marrow failure syndrome. Immune abnormalities such as decreased lymphocyte counts, inverted CD4/CD8 T-cell ratio and increased IFN-γ-producing T cells have been found in AA. CD30, a surface protein belonging to the tumor necrosis factor receptor family and releasing from cell surface as a soluble form (sCD30) after activation, marks a subset of activated T cells secreting IFN-γ when exposed to allogeneic antigens. Our study found elevated BM plasma levels of sCD30 in patients with SAA, which were closely correlated with disease severity, including absolute lymphocyte count (ALC) and absolute netrophil count (ANC). We also noted that sCD30 levels were positively correlated with plasma IFN-γ levels and CD4/CD8 T-cell ratio in patients with SAA. In order to explain these phenomena, we stimulated T cells with alloantigen in vitro and found that CD30+ T cells were the major source of IFN-γ, and induced CD30+ T cells from patients with SAA produced significantly more IFN-γ than that from healthy individuals. In addition, increased proportion of CD8+ T cells in AA showed enhanced allogeneic response by the fact that they expressed more CD30 during allogeneic stimulation. sCD30 levels decreased in patients responded to immunosuppressive therapy. In conclusion, elevated BM plasma levels of sCD30 reflected the enhanced CD30+ T cell-mediated immune response in SAA. CD30 as a molecular marker that transiently expresses on IFN-γ-producing T cells, may participate in mediating bone marrow failure in AA, which also can facilitate our understanding of AA pathogenesis to identify new therapeutic targets. PMID:25383872

Effects of methionine deficiencies on plasma levels of thyroid hormones, insulin-like growth factors-I and -II, liver and body weights, and feed intake in growing chickens.

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Carew, L B; McMurtry, J P; Alster, F A

2003-12-01

We showed previously that Met deficiency at 0.25% of the diet causes elevations in plasma triiodothyronine (T3) in broilers. In the present study, plasma levels of thyroid hormones as well as insulin-like growth factors (IGF)-I and -II were measured in chicks fed 3 deficient levels of total Met. Control (0.5%) and Met-deficient diets (0.4, 0.3, and 0.2%) were fed to male broilers from 8 to 22 d of age. Additional groups of control chicks were pair-fed with the Met-deficient ones. Chicks receiving 0.4% Met increased feed intake by 10% with no significant change in body weight. The more severe Met deficiencies of 0.3 and 0.2% caused graded reductions in feed intake and weight gain. However, corresponding pair-fed control chicks were significantly heavier. These changes suggest more marked alterations in metabolic processes with 0.3 and 0.2% Met than with 0.4% Met. Liver weights were heavier in chicks fed 0.3 and 0.2% Met but not 0.4%. Plasma T3 was higher in all deficient chicks compared with the free-fed control, which was significant only with 0.3% Met. However, with 0.3 and 0.2% Met, plasma T3 was significantly elevated compared to pair-fed controls. Plasma thyroxine (T4) was lower in all deficient groups, which was significant only with 0.2% Met, whereas no significant differences occurred between deficient chicks and their pair-fed controls. Plasma IGF-I levels were not significantly different, but they were consistently lower in deficient chicks and deserve further study. Plasma IGF-II was significantly less in chicks fed 0.2% Met compared to pair-fed controls suggesting that Met deficiency interferes with IGF-II metabolism. We concluded that a deficit of dietary Met altered plasma T3 and IGF-II levels, but the effect was dependent on the degree of deficiency.

Scottish immunoassay support service quality control scheme for thyroxine, triiodothyronine, and digoxin assays: analysis of first 18 months' experience

International Nuclear Information System (INIS)

Ratcliffe, W.A.; Logue, F.C.; Ratcliffe, J.G.

1978-01-01

Initial experience of the Scottish Immunoassay Support Service Quality Control scheme for thyroxin(T4), triiodothyronine (T3), and digoxin is analysed. For T4, radioimmunoassay (RIA) methods gave values close to the all-method mean. Competitive protein binding (CPB) kits gave values significantly higher (by 12%) in one and lower (by 10%) in another, probably due to the extraction of interfering substances such as non-esterified fatty acids or thyroid hormone binding proteins. The range of between-batch precision of individual laboratories was 10.8-47.5% (mean 17.8%) over the clinically relevant range. It was particularly poor at levels below the lower limit of the normal range. For T3 RIA, kit methods gave significantly higher values than independent methods although recovery of exogenous T3 was approximately quantitative with both. Cross reaction of T4 in T3 assays was insignificant. The range of between-batch precision for individual laboratories was 11.4-35.5% (mean 21.9%), and was poorest at levels of 1 nmol/l or less. For digoxin RIA, Lanoxitest γ gave significantly higher values than other methods, and over-recovered exogenous digoxin. The range of between-batch precision was 13.8-35.2% (mean 21.6%), and was poorest at levels of 1 nmol/l or less. The distribution of liquid human serum specimens at ambient temperature was satisfactory for quality control of T4, T3, and digoxin RIA but not for T4 by the Thyopac 4 method. Ox serum was unsuitable for certain T4 RIA methods. (author)

Third ventricle neuropeptide-Y infusion effect on metabolic ...

African Journals Online (AJOL)

The goal of this study was to determine whether neuropeptide-Y affects the mean plasma concentrations of metabolic parameters such as thyroxine (T4), triiodothyronine (T3), growth hormone (GH), insulin, glucagon, glucose, fatty acid and urea in the goats fed different energy content in diets. 16 goats were randomly ...

Radioimmunoassay for male canine plasma 4-androstenedione, testosterone and 5α-dihydrotestosterone

International Nuclear Information System (INIS)

Inaba, Toshio; Shimizu, Ryosuke; Imori, Tatsuo

1977-01-01

The radioimmunoassay for the simultaneous measurement of 4-androstenedione (A), testosterone (T), and 5α-dihydrotestosterone (DHT) in canine plasma was carried out. The assay for these 3 plasma steroids showed to be satisfactorily sensitive, specific, and accurate. The plasma steroid levels of peripheral and spermary vein plasma collected from 15 male dogs were (A) 0.86 +-0.75, (T) 1.19+-1.05 and (DHT) 0.30+-0.25 in peripheral vein, and (A) 30.2+-18.5, (T) 157+-98 and (DHT) 17.5+-10.7 in spermary vein, respectively (ng/ml and SD). Analysing these data, the significant correlation between two vein plasma levels was suggested. In order to estimate the normal or common diurnal variations of these plasma steroid levels in male dogs, 5 animals were employed, and their peripheral plasma samples were collected every an hour or two, throughout 24 hour period. In these data, the frequent intermittent peaks of plasma steroids were observed in each dog, and these seem to be their own diurnal changes. It was concluded that the peripheral plasma levels of A, T, and DHT were correlated to those in spermary vein, and these steroid levels were seemingly reflected by the episodic secretion from the gonads. (Kobatake, H.)

Conversion of the thyroxin (T4) in 3,5,3'-triiodothyronin (T3) and 3,3',5'-triiodothyronin (T3 reverse) in human leukocytes suspensions. Hyperthyroidism and hypothyroidism studies

International Nuclear Information System (INIS)

Bianco, A.C.; Douglas, C.R.; Marone, M.M.; Scalissi, N.M.; Correa, P.H.S.

1984-01-01

The peripheral metabolism of thyroid hormones was studied in suspensions of human leukocytes through the evaluation of in vitro generation of T 3 and rT 3 (RIA) from non-radioactive T 4 . Increased in vitro generation of T 3 and rT 3 was observed in suspensions from hyperthyroid patients, while a significant decrease was evidenced when leukocytes from hypothyroid patients were used. These alterations are apparently due to the excess and lack of thyroid hormones, respectively, since they could be reserved in both cases by specific clinical treatment. (author) [pt

Measurement for serum thyroxine-binding globulin (TBG) and its clinical assessment in diagnosis of thyroid states

International Nuclear Information System (INIS)

Imamura, Rikiyo; Yoshimasa, Yasunao; Hamada, Satoshi

1979-01-01

Serum levels of thyroxine (T 4 )-binding globulin (TBG) were determined by a radioimmunoassay using cellulose-linked antibody to TBG. Values obtained in healthy young adults averaged 1.62 +- 0.25 (SD) mg/100 ml, and no significant difference was detected between males and females. The TBG levels remained within the normal limit in hyperthyroidism while they were significantly increased in hypothyroidism. Interestingly enough, TBG levels were significantly elevated in chronic thyroidities with no overt hypothyroidism. In normal pregnancy, TBG was increased slightly in the first trimester, and markedly in the second and third trimesters. In one case of congenital TBG deficiency, no immunoreactive TBG was detected. It was demonstrated, further, that an inverse relationship (r = -0.7593) existed between the TBG level and serum triiodothyronine uptake index, and that a direct relation (r = +0.6557) was present between the TBG level and T 4 in sera from normal subjects and pregnancy. Ratios of T 4 /TBG were markedly increased in hyperthyroidism, and decreased in hypothyroidism, showing no overlap with the normal subjects, whereas they were below the normal limit in half the cases in the second and third trimesters of pregnancy. The radioimmunoassay for TBG was useful in evaluating hypothyroid states, because it could differentiate the increase in T 4 associated with elevated TBG from hyperthyroidism. (author)

Serum levels of T3 and T4 among workers of contraceptive pills industry

International Nuclear Information System (INIS)

Abbas, E.Z.; Emara, A.; Yassen, Y.Z.; Amr, M.M.; Jaras, M.S.

1985-01-01

Serum levels of thyroxine and triiodothyronine were determined in 24 workers engaged in contraceptive pills industry and 20 control subjects. Serum thyroxine in exposed subjects was significantly lower, compared to its level in controls. On the other hand, triiodothyronine was significantly higher in exposed workers. Thus, it is concluded that exposure to the dust of contraceptive drugs, namely estrogen and progesterone, produced disturbances in thyroid gland function and thyroid hormone metabolism. (author)

Retinal S-opsin dominance in Ansell's mole-rats (Fukomys anselli) is a consequence of naturally low serum thyroxine.

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Henning, Yoshiyuki; Mladěnková, Nella; Burda, Hynek; Szafranski, Karol; Begall, Sabine

2018-03-12

Mammals usually possess a majority of medium-wavelength sensitive (M-) and a minority of short-wavelength sensitive (S-) opsins in the retina, enabling dichromatic vision. Unexpectedly, subterranean rodents from the genus Fukomys exhibit an S-opsin majority, which is exceptional among mammals, albeit with no apparent adaptive value. Because thyroid hormones (THs) are pivotal for M-opsin expression and metabolic rate regulation, we have, for the first time, manipulated TH levels in the Ansell's mole-rat (Fukomys anselli) using osmotic pumps. In Ansell's mole-rats, the TH thyroxine (T4) is naturally low, likely as an adaptation to the harsh subterranean ecological conditions by keeping resting metabolic rate (RMR) low. We measured gene expression levels in the eye, RMR, and body mass (BM) in TH-treated animals. T4 treatment increased both, S- and M-opsin expression, albeit M-opsin expression at a higher degree. However, this plasticity was only given in animals up to approximately 2.5 years. Mass-specific RMR was not affected following T4 treatment, although BM decreased. Furthermore, the T4 inactivation rate is naturally higher in F. anselli compared to laboratory rodents. This is the first experimental evidence that the S-opsin majority in Ansell's mole-rats is a side effect of low T4, which is downregulated to keep RMR low.

Significant reduction of peripheral blood interleukin-35 and CD4+EBI3+ T cells, which are negatively correlated with an increase in the plasma IL-17 and cTnI level, in viral myocarditis patients

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Han Ouyang

2017-02-01

Full Text Available Introduction: Viral myocarditis (VMC has become an increasingly common heart disease that endangers human health. In the present study, the plasma interleukin-35 (IL-35 level and the percentage of CD4 + EBI3 + T cells in VMC patients were detected to investigate the significance of changes in these parameters in the plasma of VMC patients and their association with the disease. Material and methods: ELISA was performed to detect the plasma IL-35 level and the percentage of peripheral blood CD4 + EBI3 + T cells in 40 VMC patients and in 20 healthy individuals. Moreover, the plasma IL-17 levels in the VMC patients and in the healthy individuals were detected using an ELISA, and the cardiac Troponin-I (cTnI levels were detected using a chemiluminescent microparticle immunoassay to compare the differences in the groups. Results : Plasma IL-35 level and the percentage of CD4 + EBI3 + T cells in acute phase VMC patients was lower than that in the healthy control group and the convalescent phase VMC patients. Additionally, the plasma IL-35 level in the VMC patients exhibited a negative correlation with the levels of cTnI and IL-17. The percentage of CD4 + EBI3 + T cells also showed a negative correlation with the levels of cTnI and IL-17. Conclusions : The plasma IL-35 level and the percentage of CD4 + EBI3 + T cells in VMC patients was reduced, and the amount of the decrease was associated with the severity of the disease. These results suggest that IL-35 and CD4 + EBI3 + T might play important roles in the progression of VMC and could be used as indictors of the disease.

Direct determination of free thyroxine in two simultaneous radioimmunoassays with different test principles

International Nuclear Information System (INIS)

Lohkamp, F.; Schmidt, M.

1982-01-01

Serum FT 4 was measured simultaneously by the commercial FT 4 kits of Amersham-Buchler and Corning Medical in 4 groups with defined thyroid function as follows: 57 euthroid subjects with and without goitre, 27 patients on T 4 supplementation. 12 subjects on oral contraceptives and 26 subclinically hyperthyroid patients. All patients underwent physical examination, thyroid scintigraphy and additional in-vitro tests (total thyroxine T 4 , total triiodothyronine T 3 and TRH/TSH assay). Both assays generally correlated well with the definded thyroid functional status except for the patients on oral contraceptives. Contrary to the FT 4 -test (Amersham-Buchler) in this group the FT 4 -test (Corning Medical) produced a significantly increased mean for FT 4 as compared to the euthyroid group thus indicating a probably insufficient compensation for high but not necessarily abnormal levels of TBG concentration. Using the FT 4 -assay (Amersham-Buchler) the normal range of FT 4 values of euthyroid subjects from the area of Bamberg with marked iodine deficiency agrees well with recently published results of a multicentre trial thus confirming the assumption of serum FT 4 not being strongly dependent on iodine intake. The results of the FT 4 -test (Corning) showed a wider scatter of normal ranges of FT 4 values for all groups and concomitantly reduced discrimination compared to the corresponding simultaneously obtained FT 4 -test (Amersham-Buchler) results. Though cost and time saving, the commercial radioimmunoassays will require further critical evaluation of normal range validity on larger populations of defined abnormalities will require further critical evaluation of normal range validity on larger populations of defined abnormalities of thyroid function to elucidate inherent deficiencies of the new FT 4 methods and of their diagnostic efficiency. (orig./MG) [de

Simulation of Post-Thyroidectomy Treatment Alternatives for Triiodothyronine or Thyroxine Replacement in Pediatric Thyroid Cancer Patients

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Ben-Shachar, Rotem; Huang, Stephen A.; DiStefano, Joseph J.

2012-01-01

Background As in adults, thyroidectomy in pediatric patients with differentiated thyroid cancer is often followed by 131I remnant ablation. A standard protocol is to give normalizing oral thyroxine (T4) or triiodothyronine (T3) after surgery and then withdraw it for 2 to 6 weeks. Thyroid remnants or metastases are treated most effectively when serum thyrotropin (TSH) is high, but prolonged withdrawals should be avoided to minimize hypothyroid morbidity. Methods A published feedback control system model of adult human thyroid hormone regulation was modified for children using pediatric T4 kinetic data. The child model was developed from data for patients ranging from 3 to 9 years old. We simulated a range of T4 and T3 replacement protocols for children, exploring alternative regimens for minimizing the withdrawal period, while maintaining normal or suppressed TSH during replacement. The results are presented with the intent of providing a quantitative basis to guide further studies of pediatric treatment options. Replacement was simulated for up to 3 weeks post-thyroidectomy, followed by various withdrawal periods. T4 vs. T3 replacement, remnant size, dose size, and dose frequency were tested for effects on the time for TSH to reach 25 mU/L (withdrawal period). Results For both T3 and T4 replacement, higher doses were associated with longer withdrawal periods. T3 replacement yielded shorter withdrawal periods than T4 replacement (up to 3.5 days versus 7–10 days). Higher than normal serum T3 concentrations were required to normalize or suppress TSH during T3 monotherapy, but not T4 monotherapy. Larger remnant sizes resulted in longer withdrawal periods if T4 replacement was used, but had little effect for T3 replacement. Conclusions T3 replacement yielded withdrawal periods about half those for T4 replacement. Higher than normal hormone levels under T3 monotherapy can be partially alleviated by more frequent, smaller doses (e.g., twice a day). LT4 may be the

Thyroid stimulating hormone and serum, plasma, and platelet brain-derived neurotrophic factor during a 3-month follow-up in patients with major depressive disorder.

Science.gov (United States)

Baek, Ji Hyun; Kang, Eun-Suk; Fava, Maurizio; Mischoulon, David; Nierenberg, Andrew A; Lee, Dongsoo; Heo, Jung-Yoon; Jeon, Hong Jin

2014-12-01

Thyroid dysfunction and elevated thyroid stimulating hormone (TSH) are common in patients with depression. TSH might exert its function in the brain through blood levels of brain-derived neurotrophic factor (BDNF). BDNF decreases during depressed states and normalize after treatment. The gap is that the association between TSH and BDNF in patients with major depressive disorder (MDD) is unknown. We studied 105 subjects ≥18 years of age with MDD and measured serum, plasma, and platelet BDNF at baseline, 1 month and 3 months during antidepressant treatment. Other baseline measurements included hypothalamic-pituitary-thyroid axis hormones such as TSH, triiodothyronine (T3) and thyroxine (T4); hypothalamic-pituitary-adrenal (HPA) axis hormones and hypothalamic-pituitary-gonadal (HPG) axis hormones and prolactin. Linear mixed model effect analyses revealed that baseline TSH level was negatively associated with changes of serum BDNF from baseline to 3 months (F=7.58, p=0.007) after adjusting for age, sex, and body mass index, but was not associated with plasma and platelet BDNF. In contrast, T3 and T4, HPA axis hormones, HPG axis hormones, and prolactin were not associated with serum, plasma, or platelet BDNF levels. Patients in the highest quartile of TSH showed significantly lower serum BDNF than in the other quartiles (F=4.54, p=0.038), but no significant differences were found based on T3 and T4 levels. TSH was only measured at baseline. Higher TSH is associated with lower baseline and reduced the increase of serum BDNF levels during antidepressant treatment in patients with MDD. Copyright © 2014 Elsevier B.V. All rights reserved.

Original Research: Metabolic alterations from early life thyroxine replacement therapy in male Ames dwarf mice are transient.

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Darcy, Justin; Fang, Yimin; Hill, Cristal M; McFadden, Sam; Sun, Liou Y; Bartke, Andrzej

2016-10-01

Ames dwarf mice are exceptionally long-lived due to a Prop1 loss of function mutation resulting in deficiency of growth hormone, thyroid-stimulating hormone and prolactin. Deficiency in thyroid-stimulating hormone and growth hormone leads to greatly reduced levels of circulating thyroid hormones and insulin-like growth factor 1, as well as a reduction in insulin secretion. Early life growth hormone replacement therapy in Ames dwarf mice significantly shortens their longevity, while early life thyroxine (T4) replacement therapy does not. Possible mechanisms by which early life growth hormone replacement therapy shortens longevity include deleterious effects on glucose homeostasis and energy metabolism, which are long lasting. A mechanism explaining why early life T4 replacement therapy does not shorten longevity remains elusive. Here, we look for a possible explanation as to why early life T4 replacement therapy does not impact longevity of Ames dwarf mice. We found that early life T4 replacement therapy increased body weight and advanced the age of sexual maturation. We also find that early life T4 replacement therapy does not impact glucose tolerance or insulin sensitivity, and any deleterious effects on oxygen consumption, respiratory quotient and heat production are transient. Lastly, we find that early life T4 replacement therapy has long-lasting effects on bone mineral density and bone mineral content. We suggest that the transient effects on energy metabolism and lack of effects on glucose homeostasis are the reasons why there is no shortening of longevity after early life T4 replacement therapy in Ames dwarf mice. © 2016 by the Society for Experimental Biology and Medicine.

Seasonal variations in TSH serum levels in athyreotic patients under L-thyroxine replacement monotherapy.

Science.gov (United States)

Gullo, Damiano; Latina, Adele; Frasca, Francesco; Squatrito, Sebastiano; Belfiore, Antonino; Vigneri, Riccardo

2017-08-01

Whether serum TSH undergoes seasonal fluctuations in euthyroid and hypothyroid residents of temperate climates is controversial. Monthly TSH and thyroid hormone levels were cross-sectionally analysed in a large cohort of euthyroid subjects (n=11 806) and L-thyroxine (L-T4)-treated athyreotic patients (n=3 934). Moreover, in a small group (n=119) of athyreotic patients treated with an unchanged dosage of L-T4 monotherapy, hormones were measured both in the coldest and in the hottest seasons of the same year (longitudinal study). No seasonal hormone change was observed in the euthyroid subjects except for a small FT3 increase in winter (+2.9%, P<.001). In contrast, the L-T4-treated athyreotic patients had significantly higher serum TSH values in the cold season when the FT4 values were significantly lower. The differences were more notable in the longitudinal series (TSH, 0.80 vs. 0.20 mU/L and FT4, 16.3 vs. 17.8 pmol/L in December-March vs. June-September, respectively). In these patients also serum FT3 values significantly decreased in winter (in the longitudinal series, 3.80 in winter vs 4.07 pmol/L in summer). Regression analysis showed that in athyreotic subjects, a greater FT4 change is required to obtain a TSH change similar to that of euthyroid controls and that this effect is more pronounced in the summer. Athyreotic patients undergoing L-T4 monotherapy have abnormal seasonal variations in TSH. These changes are secondary to the FT4 and FT3 serum decreases in winter, which occur in spite of the constant treatment. The underlying mechanisms are unclear, but in some cases, these changes may be clinically relevant. © 2017 John Wiley & Sons Ltd.

Effects of larval-juvenile treatment with perchlorate and co-treatment with thyroxine on zebrafish sex ratios

Science.gov (United States)

Mukhi, S.; Torres, L.; Patino, R.

2007-01-01

The objective of this study was to determine the effect of larval-juvenile exposure to perchlorate, a thyroid hormone synthesis inhibitor, on the establishment of gonadal sex ratios in zebrafish. Zebrafish were exposed to untreated water or water containing perchlorate at 100 or 250 ppm for a period of 30 days starting at 3 days postfertilization (dpf). Recovery treatments consisted of a combination of perchlorate and exogenous thyroxine (T4; 10 nM). Thyroid histology was assessed at the end of the treatment period (33 dpf), and gonadal histology and sex ratios were determined in fish that were allowed an additional 10-day period of growth in untreated water. As expected, exposure to perchlorate caused changes in thyroid histology consistent with hypothyroidism and these effects were reversed by co-treatment with exogenous T4. Perchlorate did not affect fish survival but co-treatment with T4 induced higher mortality. However, relative to the corresponding perchlorate concentration, co-treatment with T4 caused increased mortality only at a perchlorate concentration of 100 ppm. Perchlorate alone or in the presence of T4 suppressed body length at 43 dpf relative to control values. Perchlorate exposure skewed the sex ratio toward female in a concentration-dependent manner, and co-treatment with T4 not only blocked the feminizing effect of perchlorate but also overcompensated by skewing the sex ratio towards male. Moreover, co-treatment with T4 advanced the onset of spermatogenesis in males. There was no clear association between sex ratios and larval survival or growth. We conclude that endogenous thyroid hormone plays a role in the establishment of gonadal sex phenotype during early development in zebrafish. ?? 2006 Elsevier Inc. All rights reserved.

Preliminary results of a new radioimmunoassay for thyroxine binding globulin (T.B.G.)

International Nuclear Information System (INIS)

Bisset, J.-P.; Sauvan, R.; Roux, F.; Hourtoule, P.

1978-01-01

A radioimmunoassay for the accurate measurement of T.B.G., developed by Crouzat-Reynes, was used to perform T.B.G. concentration in sera of euthyroid subjects in different clinical situations, in hypothyroid and hyperthyroid patients. In normal control, the T.B.G. concentration was not different from men and women, from young and old subjects. On the other hand, in women either pregnant or receving oral contraception, the T.B.G. levels were significantly higher than euthyro subjects. Cirrhosis of the liver and liver carcinoma were without apparent effect on T.B.G. levels because it was a too few number of patients and the group was too heterogeneous. In the group of hypothyroid and hyperthyroid patients, the T.B.G. serum concentrations were not significantly different from normal. The ratio T4/T.B.G. as I.T.L. (T4 x T3 uptake) permit to bring back in normal range T4 levels changed by extrathyroidal process; however, this ratio seems to be less interesting than standard I.T.L. The T.B.G. assay has not to be considered only as a substitution of T3 uptake because they do not study the same parameters [fr

Hepatic sinusoid is not well-stirred: estimation of the degree of axial mixing by analysis of lobular concentration gradients formed during uptake of thyroxine by the perfused rat liver

International Nuclear Information System (INIS)

Weisiger, R.A.; Mendel, C.M.; Cavalieri, R.R.

1986-01-01

Two general models have been proposed for predicting the effects of metabolism, protein binding, and plasma flow on the removal of drugs by the liver. These models differ in the degree of plasma mixing assumed to exist within each hepatic sinusoid. The venous equilibrium model treats the sinusoid as a single well-stirred compartment, whereas the sinusoidal model effectively breaks up the sinusoid into a large number of sequentially perfused compartments which do not exchange their contents except through plasma flow. As a consequence, the sinusoidal model, but not the venous equilibrium model, predicts that the concentration of highly extracted drugs will decline as the plasma flows through the hepatic lobule. To determine which of these alternative models best describes the hepatic uptake process, we looked for evidence that concentration gradients are formed during the uptake of [ 125 I]thyroxine by the perfused rat liver. Autoradiography of tissue slices after perfusion of the portal vein at physiologic flow rates with protein-free buffer containing [ 125 I]thyroxine demonstrated a rapid exponential fall in grain density with distance from the portal venule, declining by half for each 8% of the mean length of the sinusoid. Reversing the direction of perfusate flow reversed the direction of the autoradiographic gradients, indicating that they primarily reflect differences in the concentration of thyroxine within the hepatic sinusoids rather than differences in the uptake capacity of portal and central hepatocytes. Analysis of the data using models in which each sinusoid was represented by different numbers of sequentially perfused compartments (1-20) indicated that at least eight compartments were necessary to account for the magnitude of the gradients seen

Selenium derivatives of thyroxine and tri-iodothyronine

International Nuclear Information System (INIS)

Cree, G.M.

1980-01-01

Novel selenium derivatives of thyroxine and tri-iodothyronine are described. They preferably contain at least one 75 Se atom. The compounds are useful in dual isotope assays of thyroid function. (U.K.)

Radioimmunological determination of total thyroxine in the serum

Energy Technology Data Exchange (ETDEWEB)

Premachandra, Bhartur

1975-09-04

A radioimmunological method to determine total thyroxine in a serum sample is described. The method is as follows: trichloracetic acid and sodium hydroxide are mixed with the sample; radioactive thyroxine is added to the mixture, which is left to reach equilibrium then placed in contact with a resin sponge consisting of a polyurethane foam with intercommunicating cells containing a strongly basic anion exchange resin; the mixture and the resin sponge are incubated, the initial radioactivity of the mixture and resin sponge combination is measured with an appropriate detection system, then the resin sponge is removed from the mixture, washed and its residual radioactivity measured.

Radioimmunological determination of total thyroxine in the serum

International Nuclear Information System (INIS)

Premachandra, Bhartur.

1975-01-01

A radioimmunological method to determine total thyroxine in a serum sample is described. The method is as follows: trichloracetic acid and sodium hydroxide are mixed with the sample; radioactive thyroxine is added to the mixture, which is left to reach equilibrium then placed in contact with a resin sponge consisting of a polyurethane foam with intercommunicating cells containing a strongly basic anion exchange resin; the mixture and the resin sponge are incubated, the initial radioactivity of the mixture and resin sponge combination is measured with an appropriate detection system, then the resin sponge is removed from the mixture, washed and its residual radioactivity measured [fr

Evaluation and comparison of radio-, fluorescence, and enzyme-linked immunoassays for serum thyroxine

International Nuclear Information System (INIS)

Kaplan, L.A.; Gau, N.; Fearn, J.; Steain, E.A.; Chen, I.W.; Maxon, H.; Volle, C.

1981-01-01

We have compared three analytical systems for the measurement of serum thyroxine: enzyme-linked immunoassay (EIA), fluorescent immunoassay (FIA) and a radioimmunoassay (RIA). These were evaluated with respect to their precision, accuracy, analytical sensitivity and sample throughput. The RIA is more sensitive than the EIA (10 μg/L vs. 35 μg/L). Both systems have excellent precision (X=86 μg/L, C.V.sub(RIA)=C.V.sub(EIA)=4.6 percent). Both the EIA and RIA demonstrate good accuracy with recovery of between 97-98 percent of added thyroxine. The FIA has an apparent sensitiviity between that of the RIA and EIA (25 μg/L), but a precision consistently lower than the other two systems (C.V. =7.4 percent, X=86 μg/L). Patients' results by RIA compared well with those from EIA (r=0.91,P 0.05). Although not fully automated, the EIA performed on the Abbott ABA-100 analyzer has a sample throughput equal to the automated RIA system (Micromedic, Concept 4)

Study on the thyroid function of thoroughbred horses by means of 'in vitro' 125I-T3 modified and 125I-T4 tests

International Nuclear Information System (INIS)

Martin, B.W. de

1975-01-01

Sera of 71 animals, divided in groups of males and females, in repose and after activity were studied. The method to establish the percentage of the 125 I-lyothyronine retention in resin (Test 125 I-T 3 or T 3 ) was modified by the use of 0.2 ml of serum on the resin column, after addition of the marked hormone. This modification served to prove that thoroughbred equines show binding of the I-lyothyronine to the serum four times reduced, indicating, therefore, that these animals have four times more ligation sites of triidothyronin saturation in the serum, when compared with the results obtained from human beings. The variance analysis applied to the T 3 Test showed no significant results at the 95% level as regards to activity. For the 71 animals, the author has found an average of 50.30% of the 125 I-Lyothyronine in resin retention, being the confidence interval for this group between 48.75% and 51.85% to a 95% confidence coefficient. Evaluating the results of the T 4 Test by means of the variance analysis, we noticed that the male and female groups in repose differed statistically from the groups after activity to a 95% confidence coefficient. The author has grouped the results of the T 4 Test of 32 equines, 18 males and 14 females, in repose, obtaining an average of 0.61 mcg and 0.51 mcg and 0.71 mcg T 4 /100 ml as confidence interval to a 95% confidence coefficient. We have listed 39 results of T 4 Test, being 23 males and 61 Females, after activity, obtaining an average of 2.01 mcg of thyroxin by 100 ml of serum and 1.72 mcg and 2.30 T 4 /100 ml as confidence interval to a 95% confidence coefficient

Predicting thyroxine requirements following total thyroidectomy.

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Mistry, Dipan; Atkin, Stephen; Atkinson, Helen; Gunasekaran, Sinnappa; Sylvester, Deborah; Rigby, Alan S; England, R James

2011-03-01

Optimal thyroxine replacement following total thyroidectomy is critical to avoid symptoms of hypothyroidism. The aim of this study was to determine the best formula to determine the initiated replacement dose of levothyroxine immediately following total thyroidectomy. Prospective study. All patients were initiated on 100 μg levothyroxine and titrated to within the reference range for TSH and free T4. Correlations to height, weight, age, lean body mass (LBM), body surface area (BSA) and body mass index (BMI) were calculated. One hundred consecutive adult patients underwent total thyroidectomy for non-malignant disease. Comparison between three methods of levothyroxine dose prediction, aiming for a levothyroxine dose correct to within 25 μg of actual dose required. Correlations were seen between levothyroxine dose and patient age (r=-0.346, Pregression equation was calculated (predicted levothyroxine dose=[0·943 × bodyweight] + [-1.165 × age] + 125.8), simplified to (levothyroxine dose= bodyweight - age + 125) pragmatically. Initiating patients empirically on 100 μg post-operatively showed that 40% of patients achieved target within 25 μg of their required dose; this increased to 59% when using a weight-only dose calculation (1.6 μg/kg) and to 72% using the simplified regression equation. A simple calculated regression equation gives a more accurate prediction of initiated levothyroxine dose following total thyroidectomy, reducing the need for outpatient attendance for dose titration. © 2011 Blackwell Publishing Ltd.

Relationship Between Circulating Thyroid-Stimulating Hormone, Free Thyroxine, and Free Triiodothyronine Concentrations and 9-Year Mortality in Euthyroid Elderly Adults.

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Ceresini, Graziano; Marina, Michela; Lauretani, Fulvio; Maggio, Marcello; Bandinelli, Stefania; Ceda, Gian P; Ferrucci, Luigi

2016-03-01

To determine the association between plasma thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) levels and all-cause mortality in older adults who had levels of all three hormones in the normal range. Longitudinal. Community-based. Euthyroid Invecchiare in Chianti study participants aged 65 and older (N = 815). Plasma TSH, FT3, and FT4 levels were predictors, and 9-year all-cause mortality was the outcome. Cox proportional hazards models adjusted for confounders were used to examine the relationship between TSH, FT3, and FT4 quartiles and all-cause mortality over 9 years of follow-up. During follow-up (mean person-years 8,643.7, range 35.4-16,985.0), 181 deaths occurred (22.2%). Participants with TSH in the lowest quartile had higher mortality than the rest of the population. After adjusting for multiple confounders, participants with TSH in the lowest quartile (hazard ratio = 2.22, 95% confidence interval = 1.19-4.22) had significantly higher all-cause mortality than those with TSH in the highest quartile. Neither FT3 nor FT4 was associated with mortality. In elderly euthyroid subjects, normal-low TSH is an independent risk factor for all-cause mortality. © 2016, Copyright the Authors Journal compilation © 2016, The American Geriatrics Society.

Proposal of a candidate international conventional reference measurement procedure for free thyroxine in serum.

NARCIS (Netherlands)

Thienpont, L.M.; Beastall, G.H.; Christofides, N.D.; Faix, J.D.; Ieiri, T.; Jarrige, V.; Miller, W.G.; Miller, R.; Nelson, J.C.; Ronin, C.; Ross, H.A.; Rottmann, M.; Thijssen, J.H.; Toussaint, B.

2007-01-01

In the present paper the IFCC WG-STFT recommends and provides the rationale to establish metrological traceability of serum free thyroxine (FT4) measurements to a candidate international conventional reference measurement procedure. It is proposed that this procedure be based on equilibrium dialysis

Method of separating (125I)-L-thyroxine from mixture obtained by radioiodination

International Nuclear Information System (INIS)

Mucha, J.; Talan, P.; Dobias, M.

1982-01-01

( 125 I)-L-thyroxine is separated by gel filtration on a column from the mixture of ( 125 I)-L-thyroxine, ( 125 I)-L-3,5,3'-triiodothyronine and ( 125 I) - . The column is packed with a non-polar gel such as polydextran with particle size 25 to 100 μm. The mixture 1,2-propanediol/distilled water/concentrated (26%) aqueous ammonia solution, or 1,2-propanediol/concentrated (26%) aqueous ammonia solution is used as eluent. The concentration of the eluate containing ( 125 I)-L-thyroxine is adjusted with distilled water such as to establish a 50 vol.% concentration of 1,2-propanediol. (E.S.)

Increased cellular immune responses and CD4+ T-cell proliferation correlate with reduced plasma viral load in SIV challenged recombinant simian varicella virus - simian immunodeficiency virus (rSVV-SIV vaccinated rhesus macaques

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Pahar Bapi

2012-08-01

Full Text Available Abstract Background An effective AIDS vaccine remains one of the highest priorities in HIV-research. Our recent study showed that vaccination of rhesus macaques with recombinant simian varicella virus (rSVV vector – simian immunodeficiency virus (SIV envelope and gag genes, induced neutralizing antibodies and cellular immune responses to SIV and also significantly reduced plasma viral loads following intravenous pathogenic challenge with SIVMAC251/CX1. Findings The purpose of this study was to define cellular immunological correlates of protection in rSVV-SIV vaccinated and SIV challenged animals. Immunofluorescent staining and multifunctional assessment of SIV-specific T-cell responses were evaluated in both Experimental and Control vaccinated animal groups. Significant increases in the proliferating CD4+ T-cell population and polyfunctional T-cell responses were observed in all Experimental-vaccinated animals compared with the Control-vaccinated animals. Conclusions Increased CD4+ T-cell proliferation was significantly and inversely correlated with plasma viral load. Increased SIV-specific polyfunctional cytokine responses and increased proliferation of CD4+ T-cell may be crucial to control plasma viral loads in vaccinated and SIVMAC251/CX1 challenged macaques.

T3 may be a better agent than T4 in the critically ill hypothyroid patient: evaluation of transport across the blood-brain barrier in a primate model

International Nuclear Information System (INIS)

Chernow, B.; Burman, K.D.; Johnson, D.L.; McGuire, R.A.; O'Brian, J.T.; Wartofsky, L.; Georges, L.P.

1983-01-01

Thyroid hormone transport across the blood brain barrier in hypothyroid patients is clinically important yet poorly understood. To study this question, 200 micrograms of thyroxine (T4), 100 micrograms of 3,5,3'-triiodothyronine (T3) and 100 micrograms of 3,3',5'-triiodothyronine (reverse T3) were administered separately to 3 baboons, first iv and at a later date intrathecally (IT). Six animals were used. Three received the iv injections and three received the IT injections. In each of the 18 experiments, cerebrospinal fluid (CSF) and serum specimens were collected serially for 6 h after injection. Mean maximal elevations from baseline in CSF iodothyronine levels were 100 +/- 10 ng/dl after iv T4, 3921 +/- 293 ng/dl after iv T3 and 31 +/- 17 ng/dl after iv reverse T3. When given IT in the same dosages, the mean maximal increases in serum iodothyronine concentrations were: 1670 +/- 600 ng/dl for T4, 806 +/- 405 ng/dl for T3, and 210 +/- 43 ng/dl for reverse T3. In every animal studied, rapid bidirectional transfer of T3 from serum to CSF and CSF to serum occurred, whereas iv T4 resulted in delayed minimal increments in CSF T4 concentration. Isotopic experiments were also performed and the results analyzed using a kinetic model. When 125 I-T3 was given iv, the equilibrium point in CSF was observed within 90 min with 1.7% of the administered dose/L able to be counted in CSF at any moment in time. When labeled T4 was given iv, only 0.6% of the administered dose/L was counted in CSF and the equilibrium point was not reached until 360 min. These data suggest: T4, T3, and reverse T3 are all capable of bidirectional transfer across the blood brain barrier, T3 may be a better agent than T4 in treating patients with myxedema coma because T3 crosses more rapidly and more completely from serum to CSF

Role of immune activation in CD4+ T-cell depletion in HIV-1 infected Indian patients.

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Vajpayee, M; Kaushik, S; Sreenivas, V; Mojumdar, K; Mendiratta, S; Chauhan, N K

2009-01-01

The correlation of immune activation with CD4(+) depletion and HIV-1 disease progression has been evidenced by several studies involving mainly clade B virus. However, this needs to be investigated in developing countries such as India predominately infected with clade C virus. In a cross-sectional study of 68 antiretroviral treatment naïve, HIV-1 infected Indian patients, we studied the association between CD4(+) T cells, plasma HIV-1 RNA levels, and immune activation markers using unadjusted and adjusted correlative analyses. Significant negative correlations of higher magnitude were observed between the CD4(+) T cell percentages and plasma HIV-1 RNA levels in the study population when adjusted for the effects of immune activation markers. However, the negative association of CD4(+) T cells with immune activation markers remained unaffected when controlled for the effects of plasma HIV-1 RNA levels. Our results support the important role of immune activation in CD4(+) T cell depletion and disease progression during untreated HIV-1 infection.

Plasma position from ring current measurements in Extrap T1

International Nuclear Information System (INIS)

Brunsell, P.; Jin Li.

1989-11-01

The inductive coupling between the plasma and the four octupole field coils in the Extrap T1 device is utilized as a means of estimating the plasma position. The current in each octupole ring as well as the plasma current is measured by a Rogowski coil and the ring - plasma mutual inductance is then computed assuming axisymmetric plasma displacements. The obtained position is in agreement with internal magnetic probe measurements. The time - evolution of the plasma position for different external vertical and toroidal field strengths is studied. For the present discharge parameter a vertical field of about .008 T is found to give an almost radially stationary plasma. The results are compared with a simple equilibrium model

Plasma concentrations of free triiodothyronine predict weight change in euthyroid persons2

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Ortega, Emilio; Pannacciulli, Nicola; Bogardus, Clifton; Krakoff, Jonathan

2007-01-01

Background Factors that influence energy metabolism and substrate oxidation, such as thyroid hormones (THs), may be important regulators of body weight. Objective We investigated associations of THs cross-sectionally with obesity, energy expenditure, and substrate oxidation and prospectively with weight change. Design Euthyroid, nondiabetic, healthy, adult Pima Indians (n = 89; 47 M, 42 F) were studied. Percentage body fat (%BF) was measured by using dual-energy X-ray absorptiometry; sleeping metabolic rate (SMR), respiratory quotient, and substrate oxidation rates were measured in a respiratory chamber. Thyroid-stimulating hormone (TSH), free thyroxine (T4), free triiodothyronine (T3), and leptin concentrations were measured in fasting plasma samples. Results TSH, but neither free T3 nor free T4, was associated with %BF and leptin concentrations (r = 0.27 and 0.29, respectively; both: P ≤ 0.01). In multiple regression analyses adjusted for age, sex, fat mass, and fat-free mass, free T3 was a positive predictor of SMR (P = 0.02). After adjustment for age, sex, %BF, and energy balance, free T3 was a negative predictor of 24-h respiratory quotient (P < 0.05) and a positive predictor of 24-h lipid oxidation rate (P = 0.006). Prospectively, after an average follow-up of 4 ± 2 y, the mean increase in weight was 3 ± 9 kg. Baseline T3 concentrations were associated with absolute and annual percentage of changes in weight (r = −0.27, P = 0.02, and r = −0.28, P = 0.009, for the age-and sex-adjusted associations, respectively). Conclusions In euthyroid Pima Indians, lower free T3 but not free T4 concentrations were an independent predictor of SMR and lipid oxidation and a predictor of weight gain. This finding indicates that control of T4-to-T3 conversion may play a role in body weight regulation. PMID:17284741

The C-terminal domain of TRPV4 is essential for plasma membrane localization.

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Becker, Daniel; Müller, Margarethe; Leuner, Kristina; Jendrach, Marina

2008-02-01

Many members of the TRP superfamily oligomerize in the ER before trafficking to the plasma membrane. For membrane localization of the non-selective cation channel TRPV4 specific domains in the N-terminus are required, but the role of the C-terminus in the oligomerization and trafficking process has been not determined until now. Therefore, the localization of recombinant TRPV4 in two cell models was analyzed: HaCaT keratinocytes that express TRPV4 endogenously were compared to CHO cells that are devoid of endogenous TRPV4. When deletions were introduced in the C-terminal domain three states of TRPV4 localization were defined: a truncated TRPV4 protein of 855 amino acids was exported to the plasma membrane like the full-length channel (871 aa) and was also functional. Mutants with a length of 828 to 844 amino acids remained in the ER of CHO cells, but in HaCaT cells plasma membrane localization was partially rescued by oligomerization with endogenous TRPV4. This was confirmed by coexpression of recombinant full-length TRPV4 together with these deletion mutants, which resulted in an almost complete plasma membrane localization of both proteins and significant FRET in the plasma membrane and the ER. All deletions upstream of amino acid 828 resulted in total ER retention that could not rescued by coexpression with the full-length protein. However, these deletion mutants did not impair export of full-length TRPV4, implying that no oligomerization took place. These data indicate that the C-terminus of TRPV4 is required for oligomerization, which takes place in the ER and precedes plasma membrane trafficking.

[POSSIBLE CAUSES OF INEFFICIENT MONOTHERAPY OF SUBCLINICAL HYPOTHYROIDISM WITH L-THYROXIN].

Science.gov (United States)

Budnevsky, A V; Kravchenko, A Ya; Drobysheva, E S; Fes'kova, A A

2015-01-01

Substitution therapy with L-thyroxin was recognized in 2012 to be the method of choice for the treatment of subclinical hypothyroidism. However it does not always allow to achieve normalization of all metabolic parameters. The aim of our work was to search for and analyze data on the possible mechanisms responsible for the failure of replacement hormonal therapy with L-thyroxin with a view to changing the therapeutic strategy for patients with subclinical hypothyroidism.

Disruption of thyroid hormone homeostasis in Ugt1a-deficient Gunn rats by microsomal enzyme inducers is not due to enhanced thyroxine glucuronidation

International Nuclear Information System (INIS)

Richardson, Terrilyn A.; Klaassen, Curtis D.

2010-01-01

Microsomal enzyme inducers (MEI) that increase UDP-glucuronosyltransferases (UGTs) are thought to increase glucuronidation of thyroxine (T 4 ), thus reducing serum T 4 , and subsequently increasing thyroid stimulating hormone (TSH). Ugt1a1 and Ugt1a6 mediate T 4 glucuronidation. Therefore, this experiment determined the involvement of Ugt1a enzymes in increased T 4 glucuronidation, decreased serum T 4 , and increased TSH after MEI treatment. Male Wistar and Ugt1a-deficient Wistar (Gunn) rats were fed a control diet or diet containing pregnenolone-16α-carbonitrile (PCN; 800 ppm), 3-methylcholanthrene (3-MC; 200 ppm), or Aroclor 1254 (PCB; 100 ppm) for 7 days. Serum T 4 , triiodothyronine (T 3 ), and TSH concentrations, hepatic T 4 /T 3 glucuronidation, and thyroid histology and follicular cell proliferation were investigated. PCN, 3-MC, and PCB treatments decreased serum T 4 , whereas serum T 3 was maintained in both Gunn and Wistar rats (except for PCB treatment). TSH was increased in Wistar and Gunn rats after PCN (130 and 277%) or PCB treatment (72 and 60%). T 4 glucuronidation in Wistar rats was increased after PCN (298%), 3-MC (85%), and PCB (450%), but was extremely low in Gunn rats, and unchanged after MEI. T 3 glucuronidation was increased after PCN (121%) or PCB (58%) in Wistar rats, but only PCN increased T 3 glucuronidation in Gunn rats (43%). PCN treatment induced thyroid morphological changes and increased follicular cell proliferation in both strains. These data demonstrate that T 4 glucuronidation cannot be increased in Ugt1a-deficient Gunn rats. Thus, the decrease in serum T 4 , increase in TSH, and increase in thyroid cell proliferation after MEI are not dependent on increased T 4 glucuronidation, and cannot be attributed to Ugt1a enzymes.

Method for the radioimmunological in-vitro determination of thyroxine and packed test kit to carry out this method

International Nuclear Information System (INIS)

Salvatore, M.S.

1977-01-01

According to the invention a radioimmunoassay has been developed for the in-vitro determination of thyroxine in non-extracted blood serum. The radioactive thyroxine is labelled with iodine 125 or iodine 131. The corresponding antiserum contains special thyroxine antibodies. The immunogen to produce the antiserum contains a conjugate of the N-acetyl derivative of thyroxine compled to bovin serum albumin with 1-ethyl-3-(3-dimethyl-amino-propyl)-carbodiimide. (VJ) [de

Free thyroxine by solid phase radioimmunoassay: improvement in the laboratory diagnosis of thyroid status in severely ill patients

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Bayer, M.F.; McDougall, I.R. (Stanford Univ., CA (USA). School of Medicine)

1982-02-05

During severe systemic illness total thyroid hormone levels are often low, and measurement of total hormones often does not differentiate between euthyroid and hypothyroid patients. Therefore serum free thyroxine levels were tested by radioimmunoassay (antibody-coated tubes, Clinical Assays) as an alternative diagnostic test in three groups of severely ill patients with subnormal triiodothyronine. Free thyroxine estimates agreed with the clinical impression and TSH in 91% of cases in group 1 (47 patients with no history or clinical evidence of thyroid disorder), in 96% of cases in group 2 (24 euthyroid patients with a history of thyroid disease, including some on thyroid replacement) and 90% of cases in group 3 (10 hypothyroid patients). By contrast, the free thyroxine index did so in only 53% (group 1), 46% (group 2) or 100% (group 3). Sequential studies showed little change in free thyroxine and TSH levels in euthyroid patients during illness and recovery, and a good negative correlation between free thyroxine and TSH in hypothyroid patients. Free thyroxine measurements (and TSH) discriminate between euthyroid and hypothyroid sick patients better than other thyroid function tests including the free thyroxine index, and can be employed routinely: a distinct advantage over free thyroxine measured by equilibrium dialysis.

Evaluation of testosterone serum levels in testicular interstitial fluid under thyroxine influence

International Nuclear Information System (INIS)

Silva, Isvania Maria S. da; Pereira, Simey de L.S.; Souza, Grace Mary L.; Carvalho, Elaine F.M.B.; Catanho, Maria Teresa J. de A.; Silveira, Maria de Fatima G. da; Lima Filho, Guilherme L.

2000-01-01

The thyroid hormones possibly exert a reciprocal action between testicular steroids and Sertoli's cells during the premature period. This work aims to evaluate thyroxine effect on testosterone serum levels and in the testicular interstitial fluid (TIF) in rats. Wistar males rats, 22 days old, 80g of body weight, were induced to hyperthyroidism with thyroxine (20μg/kg) in periods of 5, 10, 15 and 20 consecutive days. After the treatment the animals were weighed and sacrificed for blood and testis collection. From the blood serum and from the TIF drained from the testis were performed testes in order to obtain testosterone attached to 125 I with a specific activity of 36,86 MBq/ig. The results have shown a testosterone significant lineal increase in both - serum and TIF - in the group treated with thyroxine as a time function. In the control group, testosterone levels remained low in both serum and TIF dosages. As a result, we were able to verify that the testosterone levels could be modified by thyroxine in serum and TIF. And so, it could affect luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels in hypophysis. (author)

Differentiating Graves' disease from subacute thyroiditis using ratio of serum free triiodothyronine to free thyroxine.

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Sriphrapradang, Chutintorn; Bhasipol, Adikan

2016-09-01

The measurement of free thyroid hormone, instead of the total form, is more commonly used in current practice. We aimed to evaluate the usefulness of the ratio of serum free triiodothyronine (FT3, pg/mL) to free thyroxine (FT4, ng/dL) for differentiating Graves' disease from subacute thyroiditis. Medical records of thyrotoxic patients aged >15 years who had measurement of FT3, FT4 and thyrotropin on the first diagnosis of thyrotoxicosis before initiating treatment were retrospectively reviewed. Data were collected from all clinics, and were not limited to the endocrine clinic. Pregnant women were excluded. A total of 548 patients (468 with Graves' disease, 40 with subacute thyroiditis and 40 with toxic adenoma/multinodular goiter) were recruited. Mean age was 43.9 ± 15.4 years. Most were female 434 (79.2%), and goiter was present in 55.3%. Prevalence of T3-toxicosis and T4-toxicosis were 5.6% and 6.6%, respectively. Mean FT3/FT4 ratios were 4.62 ± 2 (10(-2) pg/ng) in patients with Graves' disease and 2.73 ± 0.5 in subacute thyroiditis. The area under the ROC curve of the FT3/FT4 ratio for diagnosis of Graves' disease was 0.83 (95%CI, 0.76-0.91). Cutoff level of this ratio >4.4 offered sensitivity of 47.2% and specificity of 92.8%. FT3/FT4 ratio of >4.4 (10(-2) pg/ng) may help in differentiating the cause of thyrotoxicosis.

Cold exposure rapidly induces virtual saturation of brown adipose tissue nuclear T3 receptors

International Nuclear Information System (INIS)

Bianco, A.C.; Silva, J.E.

1988-01-01

Cold exposure induces a rapid increase in uncoupling protein (UCP) concentration in the brown adipose tissue (BAT) of euthyroid, but not hypothyroid, rats. To normalize this response with exogenous 3,5,3'-triiodothyronine (T 3 ), it is necessary to cause systemic hyperthyroidism. In contrast, the same result can be obtained with just replacement doses of thyroxine (T 4 ) and, in euthyroid rats, the normal response of UCP to cold occurs without hyperthyroid plasma T 3 levels. Consequently, the authors explored the possibility that the cold-induced activation of the type II 5'-deiodinase resulted in high levels of nuclear T 3 receptor occupancy in euthyroid rats. Studies were performed with pulse injections of tracer T 3 or T 4 in rats exposed to 4 degree C for different lengths of time (1 h-3 wk). Within 4 h of cold exposure, they observed a significant increase in the nuclear [ 125 I]T 3 derived from the tracer [ 125 I]T 4 injections (T 3 [T 4 ]) and a significant reduction in the nuclear [ 125 I]T 3 derived from [ 125 I]T 3 injections (T 3 [T 3 ]). The number of BAT nuclear T 3 receptors did not increase for up to 3 wk of observation at 4 degree C. The mass of nuclear-bound T 3 was calculated from the nuclear tracer [ 125 I]T 3 [T 3 ] and [ 125 I]T 3 [T 4 ] at equilibrium and the specific activity of serum T 3 and T 4 , respectively. By 4 h after the initiation of the cold exposure, the receptors were >95% occupied and remained so for the 3 weeks of observation. They conclude that the simultaneous activation of the deiodinase with adrenergic BAT stimulation serves the purpose of nearly saturating the nuclear T 3 receptors. This makes possible the realization of the full thermogenic potential of the tissue without causing systemic hyperthyroidism

Lack of clinical AIDS in SIV-infected sooty mangabeys with significant CD4+ T cell loss is associated with double-negative T cells

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Milush, Jeffrey M.; Mir, Kiran D.; Sundaravaradan, Vasudha; Gordon, Shari N.; Engram, Jessica; Cano, Christopher A.; Reeves, Jacqueline D.; Anton, Elizabeth; O’Neill, Eduardo; Butler, Eboneé; Hancock, Kathy; Cole, Kelly S.; Brenchley, Jason M.; Else, James G.; Silvestri, Guido; Sodora, Donald L.

2011-01-01

SIV infection of natural host species such as sooty mangabeys results in high viral replication without clinical signs of simian AIDS. Studying such infections is useful for identifying immunologic parameters that lead to AIDS in HIV-infected patients. Here we have demonstrated that acute, SIV-induced CD4+ T cell depletion in sooty mangabeys does not result in immune dysfunction and progression to simian AIDS and that a population of CD3+CD4–CD8– T cells (double-negative T cells) partially compensates for CD4+ T cell function in these animals. Passaging plasma from an SIV-infected sooty mangabey with very few CD4+ T cells to SIV-negative animals resulted in rapid loss of CD4+ T cells. Nonetheless, all sooty mangabeys generated SIV-specific antibody and T cell responses and maintained normal levels of plasma lipopolysaccharide. Moreover, all CD4-low sooty mangabeys elicited a de novo immune response following influenza vaccination. Such preserved immune responses as well as the low levels of immune activation observed in these animals were associated with the presence of double-negative T cells capable of producing Th1, Th2, and Th17 cytokines. These studies indicate that SIV-infected sooty mangabeys do not appear to rely entirely on CD4+ T cells to maintain immunity and identify double-negative T cells as a potential subset of cells capable of performing CD4+ T cell–like helper functions upon SIV-induced CD4+ T cell depletion in this species. PMID:21317533

The Expression of T Cell FOXP3 and T-Bet Is Upregulated in Severe but Not Euthyroid Hashimoto’s Thyroiditis

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Stana Tokić

2016-01-01

Full Text Available Hashimoto’s thyroiditis (HT is an organ-specific autoimmune disorder characterized by progressive thyroid failure. Th1 and Treg subset of CD4+ cells have been implicated in the pathogenesis; however, less is known about their respective roles across the spectrum of HT clinical presentations. To shed more light on CD4+ subsets role in HT, we investigated the mRNA expression levels of several Th1/Treg-associated transcription factors (T-bet/ETS1, HIF1α/BLIMP1/FOXP3 in peripheral blood T cells of 10 hypothyroid, untreated HT patients, 10 hypothyroid patients undergoing hormone replacement therapy, 12 euthyroid HT subjects, and 11 healthy controls by the qRT-PCR. Compared to euthyroid HT patients and controls, both hypothyroid (2.34-fold difference versus controls, P<0.01 and thyroxine-supplemented patients (2.5-fold, P<0.001 showed an increased FOXP3 mRNA expression in T cells. Similarly, mRNA expression levels of T-bet were upregulated in severely affected but not in euthyroid HT subjects (2.37-fold and 3.2-fold, hypothyroid and thyroxine-supplemented HT patients versus controls, resp., P<0.01. By contrast, no differences in mRNA expression levels of ETS1, BLIMP1, and HIF1α were observed across the study groups. In summary, severe but not euthyroid HT was associated with robust upregulation of T-bet and FOXP3 mRNA in peripheral T cells, independent of the thyroid hormone status but proportional to disease activity.

Severe Hypothyroidism due to the Loss of Therapeutic Efficacy of l-Thyroxine in a Patient with Esophageal Complication Associated with Systemic Sclerosis.

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Lobasso, Antonio; Nappi, Liliana; Barbieri, Letizia; Peirce, Carmela; Ippolito, Serena; Arpaia, Debora; Rossi, Francesca Wanda; de Paulis, Amato; Biondi, Bernadette

2017-01-01

Thyroid function abnormalities and thyroid autoantibodies have been frequently described in patients with systemic autoimmune diseases as systemic sclerosis (SSc). Serum TSH levels are higher in SSc patients with more severe skin diseases and a worse modified Rodnan skin score. Asymptomatic esophageal involvement due to SSc has never been described as a cause of severe hypothyroidism due to l-thyroxine (l-T4) malabsorption in patients with Hashimoto's thyroiditis (HT) and SSc. Here, we report a case of a 56-year-old female affected by both SSc and HT who developed severe hypothyroidism due to the loss of therapeutic efficacy of l-T4. Therapeutic failure resulted from the altered l-T4 absorption because of SSc esophageal complications. Clinical findings improved after the administration of oral liquid l-T4. Thyroid function completely normalized with a full clinical recovery, the disappearance of the pericardial effusion and the improvement of the pulmonary pressure. A recognition of a poor absorption is crucial in patients with hypothyroidism and SSc to reduce the risk of the subsequent adverse events. This case suggests the importance of clinical and laboratory surveillance in patients with SSc and HT because the systemic complications of these dysfunctions may worsen the prognosis of hypothyroid SSc/HT patients.

Variable Suppression of Serum Thyroxine in Female Mice of Different Inbred Strains by Triiodothyronine Administered in Drinking Water

Science.gov (United States)

Hamidi, Sepehr; Aliesky, Holly; Chen, Chun-Rong; Rapoport, Basil

2010-01-01

Background Recombinant-inbred mouse strains differ in their susceptibility to Graves'-like hyperthyroidism induced by immunization with adenovirus expressing the human thyrotropin (TSH) receptor. Because one genetic component contributing to this susceptibility is altered thyroid sensitivity to TSH receptor agonist stimulation, we wished to quantify thyroid responsiveness to TSH. For such studies, it is necessary to suppress endogenous TSH by administering L-3,5,3′-triiodothyronine (L-T3), with the subsequent decrease in serum thyroxine (T4) reflecting endogenous TSH suppression. Our two objectives were to assess in different inbred strains of mice (i) the extent of serum T4 suppression after L-T3 administration and (ii) the magnitude of serum T4 increase induced by TSH. Methods Mice were tail-bled to establish baseline-serum T4 before L-T3 administration. We initially employed a protocol of L-T3-supplemented drinking water for 7 days. In subsequent experiments, we injected L-T3 intraperitoneally (i.p.) daily for 3 days. Mice were then injected i.p. with bovine TSH (10 mU) and euthanized 5 hours later. Serum T4 was assayed before L-T3 administration, and before and after TSH injection. In some experiments, serum T3 and estradiol were measured in pooled sera. Results Oral L-T3 (3 or 5 μg/mL) suppressed serum T4 levels by 26%–64% in female BALB/c mice but >95% in males. T4 suppression in female B6 mice ranged from 0% to 90%. In C3H mice, L-T3 at 3 μg/mL was ineffective but 5 μg/mL achieved >80% serum T4 reduction. Unlike inbred mice, in outbred CF1 mice the same protocol was more effective: 83% in females and 100% suppression in males. The degree of T4 suppression was unrelated to baseline T4, T3, or estradiol, but was related to mouse weight and postmortem T3, with greater suppression in larger mice (outbred CF1 animals and inbred males). Among females with serum T4 suppression >80%, the increase in serum T4 after TSH injection was greater for BALB

Stability of /sup 131/I--thyroxine and of /sup 131/I-tri-iodothyronine: the influence of radiolytic disintegration on certain diagnostic tests

Energy Technology Data Exchange (ETDEWEB)

Reviczky, A.L.; Szanto, L.

1974-01-01

The blood-protein fractions responsible for the transport of thyroid hormones (TBG, TBPA, TBA) were assayed for their thyroxine-binding capacity in the serum of the same control subject over a one-year period, by a procedure based on the isotope-dilution technique. In the dilutions of /sup 131/I--T/sub 4/ (Amersham RCC) required for the procedure, the ratio /sup 131/I--T/sub 4/:/sup 131/I--T/sub 3/ was measured in every case. Parallel with the accumulation of /sup 131/I--T/sub 3/ resulting from deiodination of /sup 131/I--T/sub 4/, the binding capacity of the individual fractions was found to have shifted from TBG to TBPA. The fact that, in contrast to the principle of the isotope-dilution technique, the labelled substance and the non-radioactive T/sub 4/ were partly different, suggests that the measurements of radioactivity do not reflect the true binding conditions of T/sub 4/. Successive batches of /sup 131/I--T/sub 3/ were examined in the same manner, and the values of the Hamolsky test were determined in the same serum. The figures displayed little variations and /sup 131/I--T/sub 3/ was also found significantly more stable than /sup 131/I--T/sub 4/. Thus, the Hamolsky test was found to represent a fairly reliable indicator of thyroid function, in contrast to measurement of the T/sub 4/-binding capacity of the blood protein fractions by the isotope-dilution technique, the results of which are uncertain and therefore inconclusive in both clinical and therapeutic respects. It is suggested that the /sup 131/I--T/sub 4/ serving for the assays should be supplied as a substance and diluted before use, but not later than a few days after preparation. The advantages of doublet tagging are pointed out.

Development of reagents for radioimmunoassay of: triiodothyronine, thyroxine and thyrotrophin; Desarrollo de reactivos para el radioinmunoanalisis de: triyodotironina, tiroxina y tirotrofina

Energy Technology Data Exchange (ETDEWEB)

Delgado S, B.; Lavalley E, C.; Ruiz J, A.; Garcia F, C.; Zamorano A, F

1991-12-15

The radioimmunoassay (RIA) of thyroid hormones it is the but it frequents of all the studies carried out by RIA in the laboratories of Nuclear Medicine, these essays are carried out with imported reagents. In the ININ the reagents and the necessary methodology have been developed for the triiodothyronine (T3), thyroxine (T4) and thyrotrophin (TSH). The good titles of the antibodies (Ac) primary for each hormone were of 1:4,000; 1:750 and 1:1,500. The used separation system was of double Ac with PEG to 10%, with titles of 1:10 for the second Ac of lamb. The specific activity for 125-I-T3 and 125-I-T4 oscillate between 850 at 900 {mu}Ci / {mu} g: being this of 90 {mu} Ci /{mu}g for TSH. To the first two hormones they were added 1-8 aniline naftalen sulfonic acid (ANS) to concentrations of 3 and 2 mg/ml respectively. As buffer for T3 and T4 it was used Tris-HCl pH 8.6 and PBS with normal serum of rabbit (SNC) for TSH. The standards got ready in buffer or free serum of thyroid hormones. The slope of the standard curves varied between -2.3 to -2.7 and the variation intra and inter assay among 4 to 10%. It is had at the moment in the ININ with standardized reagents for the RIA of T3, T4 and TSH, it is hoped to carry out tests in other laboratories and to establish the conditions of stability more appropriate to begin the preparation of pilot reagents. (Author)

14-Day thawed plasma retains clot enhancing properties and inhibits tPA-induced fibrinolysis.

Science.gov (United States)

Huebner, Benjamin R; Moore, Ernest E; Moore, Hunter B; Shepherd-Singh, Raymond; Sauaia, Angela; Stettler, Gregory R; Nunns, Geoffrey R; Silliman, Christopher C

2017-11-01

Plasma-first resuscitation attenuates trauma-induced coagulopathy (TIC); however, the logistics of plasma-first resuscitation require thawed plasma (TP) be readily available due to the obligatory thawing time of fresh frozen plasma (FFP). The current standard is storage of TP for up to 5 days at 4°C, based on factor levels at outdate, for use in patients at risk for TIC, but there remains a 2.2% outdated wastage rate. However, the multitude of plasma proteins in attenuating TIC remains unknown. We hypothesize that TP retains the ability to enhance clotting and reduce tPA-induced fibrinolysis at 14-day storage. FFP was thawed and stored at 4°C at the following intervals: 14, 10, 7, 5, 3, and 1-day prior to the experiment. Healthy volunteers underwent blood draws followed by 50% dilution with TP stored at previously mentioned intervals as well as FFP, normal saline (NS), albumin, and whole blood (WB) control. Samples underwent tPA-modified (75 ng/mL) thrombelastography (TEG) with analysis of R-time, angle, maximum amplitude (MA), and LY30. TEG properties did not change significantly over the thawed storage. 14-day TP retained the ability to inhibit tPA-induced hyperfibrinolysis (median LY30% 9.6%) similar to FFP (5.6%), WB (14.6%), and superior to albumin (59.3%) and NS (58.1%). 14-day TP also retained faster clot formation (median angle, 66.2°) and superior clot strength (MA, 61.5 mm) to albumin (34.8°, 21.6 mm) and NS (41.6°, 32.2 mm). TP plasma stored for 14 days retains clot-enhancing ability and resistance to clot degradation similar to FFP. A clinical trial is needed to validate these in vitro results. Copyright © 2017 Elsevier Inc. All rights reserved.

Contribution of local thyroxine monodeiodination to intracellular 3,5, 3'-triiodothyronine in several tissues of hyperthyroid rats at isotopic equilibrium

International Nuclear Information System (INIS)

van Doorn, J.; van der Heide, D.; Roelfsema, F.

1984-01-01

The local conversion of T4 as a source of intracellular T3 in several organs of both hypothyroid and euthyroid rats has recently been recognized to be an important phenomenon. In the present study the source and quantity of T3 in various peripheral tissues of hyperthyroid rats were investigated. Athyreotic rats received a continuous iv infusion of T4 over a prolonged period in order to attain hyperthyroid conditions. At the same time, the animals also received a continuous iv infusion of [ 125 I]T4 and [ 131 I]T3 until isotopic equilibrium was achieved. After the animals were bled and perfused, the source and quantity of T3 in various tissue homogenates and subcellular preparations of liver, kidney, and the anterior pituitary gland were analyzed. In spite of the elevated plasma T3 and T4 levels, the concentration of T3 in the cerebral cortex and cerebellum was within the normal range. The contribution of T3 derived from local T4 to T3 conversion [Lc T3(T4)] was rather low in both parts of the brain when compared with values previously determined for euthyroid rats. Whereas previous studies revealed that Lc T3(T4) contributes significantly to the T3 in the pituitary glands of both hypothyroid and euthyroid rats, this was not the case for the hyperthyroid animals; virtually all T3 was derived from plasma. It was found that the T3 in muscle was derived exclusively from plasma. Both the liver and kidney showed high concentrations of T3. Whereas Lc T3(T4) was the main source of T3 in the liver, it contributed only a minor fraction of the total T3 content in the kidney

Influence of carbamazepin and diclofenac on the radio-T3/T4-distribution and the maximal binding capacity of thyroid hormone binding proteins

International Nuclear Information System (INIS)

Sternad, H.; Albrecher, B.; Langsteger, W.; Eber, O.

1993-01-01

Marked changes in plasma thyroid function parameters due to medication have been described in literature. We, therefore, studied the influence of routine administration of carbamazepine and diclofenac upon the radio T3/T4 distribution to specific thyroid transport proteins as well as their maximal binding capacity (MBC) for T4. Both drugs have been found to lead to changes in T3 and T4 distribution but not to any influence upon MBC. The parameters of thyroid function mostly revealed reduced FT3 and FT4 values while bTSH was affected only by carbamazepine administration. (authors)

Role of L-thyroxin in counteracting rotenone induced neurotoxicity in rats.

Science.gov (United States)

Salama, Mohamed; Helmy, Basem; El-Gamal, Mohamed; Reda, Amr; Ellaithy, Amr; Tantawy, Dina; Mohamed, Mie; El-Gamal, Aya; Sheashaa, Hussein; Sobh, Mohamed

2013-03-01

A key feature of Parkinson's disease is the dopaminergic neuronal cell loss in the substantia nigra pars compacta. Many triggering pathways have been incriminated in the pathogenesis of this disease including inflammation, oxidative stress, excitotoxicity and apoptosis. Thyroid hormone is an essential agent for the growth and maturation of neurons; moreover, it has variable mechanisms for neuroprotection. So, we tested the efficacy of (L)-thyroxin as a neuroprotectant in rotenone model of Parkinson's disease in rats. Thirty Sprague Dawley rats aged 3 months were divided into 3 equal groups. The first received daily intraperitoneal injections of 0.5% carboxymethyl cellulose (CMC) 3 mL/Kg. The second group received rotenone suspended in 0.5% CMC intraperitoneally at a dose of 3 mg/kg, daily. The third group received the same rotenone regimen subcutaneous l-thyroxine at a dose of 7.5 μg daily. All animals were evaluated regarding locomotor disturbance through blinded investigator who monitored akinesia, catalepsy, tremors and performance in open field test. After 35 days the animals were sacrificed and their brains were immunostained against anti-tyrosine hydroxylase and iba-1. Photomicrographs for coronal sections of the substantia nigra and striatum were taken and analyzed using image J software to evaluate cell count in SNpc and striatal fibers density and number of microglia in the nigrostriatal system. The results were then analyzed statistically. Results showed selective protective effects of thyroxin against rotenone induced neurotoxicity in striatum, however, failed to exert similar protection on SN. Moreover, microglial elevated number in nigrostriatal system that was induced by rotenone injections was diminished selectively in striatum only in the l-thyroxin treated group. One of the possible mechanisms deduced from this work was the selective regulation of microglia in striatal tissues. Thus, this study provides an insight into thyroxin neuroprotection

Contribution of maternal thyroxine to fetal thyroxine pools in normal rats near term

International Nuclear Information System (INIS)

Morreale de Escobar, G.; Calvo, R.; Obregon, M.J.; Escobar Del Rey, F.

1990-01-01

Normal dams were equilibrated isotopically with [ 125 I]T4 infused from 11 to 21 days of gestation, at which time maternal and fetal extrathyroidal tissues were obtained to determine their [ 125 I]T4 and T4 contents. The specific activity of the [ 125 I]T4 in the fetal tissues was lower than in maternal T4 pools. The extent of this change allows evaluation of the net contribution of maternal T4 to the fetal extrathyroidal T4 pools. At 21 days of gestation, near term, this represents 17.5 +/- 0.9% of the T4 in fetal tissues, a value considerably higher than previously calculated. The methodological approach was validated in dams given a goitrogen to block fetal thyroid function. The specific activities of the [ 125 I]T4 in maternal and fetal T4 pools were then similar, confirming that in cases of fetal thyroid impairment the T4 in fetal tissues is determined by the maternal contribution. Thus, previous statements that in normal conditions fetal thyroid economy near term is totally independent of maternal thyroid status ought to be reconsidered

Inositol and hepatic lipidosis. II. Effect of inositol supplementation and time from parturition on serum insulin, thyroxine and triiodothyronine and their relationship to serum and liver lipids in dairy cows.

Science.gov (United States)

Gerloff, B J; Herdt, T H; Wells, W W; Nachreiner, R F; Emery, R S

1986-06-01

Percutaneous liver biopsies and blood samples were obtained from 80 dairy cows in nine Michigan herds over the peripartum period. Thirty-nine cows were fed 17 g of supplemental inositol and 41 were fed a placebo. Liver biopsies were assayed for total myoinositol and triglyceride (TG) concentrations. Blood samples were assayed for serum dextran precipitable cholesterol, nonesterified fatty acids (NEFA), insulin, thyroxine (T4), free (FT4), triiodothyronine (T3) and free T3 (FT3) concentrations. Serum concentrations of insulin and the thyroid hormones decreased near parturition, with lowest concentrations occurring in the immediate postpartum period. Concentrations of T3 correlated well with T4, and the concentrations of free thyroid hormones reflected concentrations of total thyroid hormones. The percentage of hormone in the free fraction remained constant over time. Serum insulin, T3 and T4 were negatively correlated with serum NEFA and liver TG concentrations. Thyroid hormone concentrations were positively correlated with serum dextran precipitable cholesterol concentrations. Inositol supplementation was associated with reduced circulating T3 and FT3 concentrations, but not T4 and FT4 concentrations. Changes in hormone concentrations at parturition and their relationship to liver TG and serum NEFA concentrations were consistent with a metabolic adaptation by the dairy cow to the negative energy balance of early lactation.

Impact of adjusting for the reciprocal relationship between maternal weight and free thyroxine during early pregnancy.

LENUS (Irish Health Repository)

Haddow, James E

2013-02-01

Among euthyroid pregnant women in a large clinical trial, free thyroxine (FT4) measurements below the 2.5th centile were associated with a 17 lb higher weight (2.9 kg\\/m(2)) than in the overall study population. We explore this relationship further.

Effects of season, pregnancy and lactation on serum thyroxine level in dairy cattle

Energy Technology Data Exchange (ETDEWEB)

Shoda, Y [Tokyo Univ. (Japan). Faculty of Agriculture; Ishii, T

1976-11-01

Serum thyroxine level was determined monthly for fifteen Holstein cows by radio stereoassay using polyvinyl alcohol (PVF) sponge throughout a year to investigate the effects of season, pregnancy and lactation on the thyroxine level seasonably, the serum thyroxine level was low in summer, and the average level in July and August was 12.6 ..mu..g/dl, which was a half of the average winter level in January and February of 26.2 ..mu..g/dl. It became low level at the late stage of gestation, showing the lowest value of 13.7 ..mu..g/dl just before delivery, and increased suddenly in the second month of lactation attaining the highest level of 27.0 ..mu..g/dl. It reduced slightly thereafter to be 22.1 ..mu..g/dl at the end of lactation.

Urea, Uric Acid, Prolactin and fT4 Concentrations in Aqueous Humor of Keratoconus Patients.

Science.gov (United States)

Stachon, Tanja; Stachon, Axel; Hartmann, Ulrike; Seitz, Berthold; Langenbucher, Achim; Szentmáry, Nóra

2017-06-01

Keratoconus is a noninflammatory disease of the cornea associated with progressive thinning and conical shape. Metabolic alterations in the urea cycle, with changes in collagen fibril stability, oxidative stress, thyroid hormones and prolactin with regulatory effect on biosynthesis and biomechanical stability of corneal stroma, may all play a role in keratoconus etiology. Our purpose was to determine urea, uric acid, prolactin and free thyroxin (fT4) concentrations in human aqueous humor (hAH) of keratoconus and cataract patients. hAH was collected from 100 keratoconus (penetrating keratoplasty) (41.9 ± 14.9 years, 69 males) and 100 cataract patients (cataract surgery) (71.2 ± 12.4 years, 58 males). Urea, uric acid, prolactin and fT4 concentrations were measured by Siemens clinical chemistry or immunoassay system. For statistical analysis, a generalized linear model (GLM) was used. Urea concentration was 11.88 ± 3.03 mg/dl in keratoconus and 16.44 ± 6.40 mg/dl in cataract patients, uric acid 2.04 ± 0.59 mg/dl in keratoconus and 2.18 ± 0.73 mg/dl in cataract groups. Prolactin concentration was 3.18 ± 0.34 ng/ml in keratoconus and 3.33 ± 0.32 ng/ml in cataract patients, fT4 20.57 ± 4.76 pmol/l in KC and 19.06 ± 3.86 pmol/l in cataract group. Urea concentration was effected through gender (p = 0.039), age (p = 0.001) and diagnosis (p = 0.025). Uric acid concentration was not effected through any of the analyzed parameters (p > 0.056). Prolactin and fT4 concentration were effected only through diagnosis (p = 0.009 and p = 0.006). Urea and prolactin concentrations are decreased, fT4 concentration is increased in aqueous humor of keratoconus patients, and uric acid concentration remains unchanged. Urea concentration in aqueous humor is also increased in older and male patients. Therefore, metabolic disorder and hormonal balance may both have an impact on keratoconus development. Further studies are necessary to assess the specific impact.

Thyroxin Is Useful to Improve Sperm Motility

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Mendeluk Gabriela Ruth

2016-07-01

Full Text Available Background The aim of this study was to evaluate the non-genomic action of thyroxin on sperm kinetic and its probable use to improve sperm recovery after applying an en- richment method like “swim-up” in comparison with the available one, pentoxifylline. Materials and Methods This is an experimental study. A total of 50 patients were re- cruited, followed by infertility consultation. Conventional sperm assays were performed according to World Health Organization criteria-2010 (WHO-2010. A Computer Aided Semen Analysis System was employed to assess kinetic parameters and concentrations. Number of the motile sperm recovered after preparation technique was calculated. Results Addition of T4 (0.002 µg/ml to semen samples increased hypermotility at 20 minutes (control: 14.18 ± 5.1% vs. 17.66 ± 8.88%, P<0.03, data expressed as mean ± SD and remained unchanged after 40 minutes. Significant differences were found in the motile sperm recovered after swim-up (control: 8.93×106 ± 9.52× 06vs. 17.20×106 ± 21.16×106, P<0.03, achieving all of the tested samples a desirable threshold value for artificial insemination outcome, while adding pentoxifylline increased the number of recovered sperm after swim-up in 60% of the studied cases. No synergism between two treatments could be determined. Conclusion We propose a new physiological tool to artificially improve insemination. The discussion opens windows to investigate unknown pathways involved in sperm ca- pacitation and gives innovative arguments to better understand infertility mechanisms.

Thyroid dysfunction in human immunodeficiency virus-infected children and its correlation with CD4 + T lymphocyte count

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Satyakumar Thongam

2015-01-01

Full Text Available Context: Thyroid dysfunction has been reported in human immunodeficiency virus (HIV-infected individuals including children. Some studies have reported that thyroid dysfunction may be a marker of severity or progression of HIV. Aims: The aim was to study thyroid function in HIV-infected children with and without highly active anti-retroviral therapy (HAART. Settings and Design: Cross-sectional study carried out at a teaching hospital with Anti-Retroviral Therapy Centre (Centre of Excellence of National AIDS Control Organization. Subjects and Methods: Thyroid stimulating hormone (TSH, total thyroxine (T4, and total tri-iodothyronine (T3 were analyzed in 60 pediatric HIV cases: 30 on HAART and 30 HAART naive. Correlation of T3, T4, and TSH with CD4 count was assessed. Statistical Analysis Used: Data reported as mean ± standard deviation and as the number of cases and percentages. Comparison between groups was done by independent sample t-test and χ2 -test. Spearman′s correlation coefficient is used to assess the association between thyroid dysfunction and CD4 count. Results: Thyroid function abnormality was seen in five out of 30 patients in both patients on HAART or without HAART therapy. Among patients on HAART, three had hypothyroidism, and two had biochemical feature of sick euthyroid syndrome. Among the HAART naive group, sub-clinical hypothyroisim was seen in four, and one had biochemical feature of sick euthyroid syndrome. None of the patients had clinical features of thyroid dysfunction. There is a highly significant correlation (P = 0.01 between TSH and CD4 count. Conclusions: Thyroid dysfunction is quite common among pediatric HIV cases. An inverse correlation is seen between TSH and CD4 count indicating trend for hypothyroidism as HIV disease progress.

Pediatric Reference Intervals for Free Thyroxine and Free Triiodothyronine by Equilibrium Dialysis-Liquid Chromatography-Tandem Mass Spectrometry.

Science.gov (United States)

La'ulu, Sonia L; Rasmussen, Kyle J; Straseski, Joely A

2016-03-05

Thyroid hormone concentrations fluctuate during growth and development. To accurately diagnose thyroid disease in pediatric patients, reference intervals (RIs) should be established with appropriate age groups from an adequate number of healthy subjects using the most exact methods possible. Obtaining statistically useful numbers of healthy patients is particularly challenging for pediatric populations. The objective of this study was to determine non-parametric RIs for free thyroxine (fT4) and free triiodothyronine (fT3) using equilibrium dialysis-high performance liquid chromatography-tandem mass spectrometry with over 2200 healthy children 6 months-17 years of age. Subjects were negative for both thyroglobulin and thyroid peroxidase autoantibodies and had normal thyrotropin concentrations. The study included 2213 children (1129 boys and 1084 girls), with at least 120 subjects (average of 125) from each year of life, except for the 6 month to 1 year age group (n=96). Non-parametric RIs (95th percentile) for fT4 were: 18.0-34.7 pmol/L (boys and girls, 6 months-6 years) and 14.2-25.7 pmol/L (boys and girls, 7-17 years). RIs for fT3 were: 5.8-13.1 pmol/L (girls, 6 months-6 years); 5.7-11.8 pmol/L (boys, 6 months-6 years); 5.7-10.0 pmol/L (boys and girls, 7-12 years); 4.5-8.6 pmol/L (girls, 13-17 years); and 5.2-9.4 pmol/L (boys, 13-17 years). Numerous significant differences were observed between pediatric age groups and previously established adult ranges. This emphasizes the need for well-characterized RIs for thyroid hormones in the pediatric population.

Contribution of local thyroxine monodeiodination to intracellular 3,5, 3'-triiodothyronine in several tissues of hyperthyroid rats at isotopic equilibrium

Energy Technology Data Exchange (ETDEWEB)

van Doorn, J.; van der Heide, D.; Roelfsema, F.

1984-07-01

The local conversion of T4 as a source of intracellular T3 in several organs of both hypothyroid and euthyroid rats has recently been recognized to be an important phenomenon. In the present study the source and quantity of T3 in various peripheral tissues of hyperthyroid rats were investigated. Athyreotic rats received a continuous iv infusion of T4 over a prolonged period in order to attain hyperthyroid conditions. At the same time, the animals also received a continuous iv infusion of (/sup 125/I)T4 and (/sup 131/I)T3 until isotopic equilibrium was achieved. After the animals were bled and perfused, the source and quantity of T3 in various tissue homogenates and subcellular preparations of liver, kidney, and the anterior pituitary gland were analyzed. In spite of the elevated plasma T3 and T4 levels, the concentration of T3 in the cerebral cortex and cerebellum was within the normal range. The contribution of T3 derived from local T4 to T3 conversion (Lc T3(T4)) was rather low in both parts of the brain when compared with values previously determined for euthyroid rats. Whereas previous studies revealed that Lc T3(T4) contributes significantly to the T3 in the pituitary glands of both hypothyroid and euthyroid rats, this was not the case for the hyperthyroid animals; virtually all T3 was derived from plasma. It was found that the T3 in muscle was derived exclusively from plasma. Both the liver and kidney showed high concentrations of T3. Whereas Lc T3(T4) was the main source of T3 in the liver, it contributed only a minor fraction of the total T3 content in the kidney.

Effects of season, pregnancy and lactation on serum thyroxine level in dairy cattle

International Nuclear Information System (INIS)

Shoda, Yoichi; Ishii, Tadao.

1976-01-01

Serum thyroxine level was determined monthly for fifteen Holstein cows by radio stereoassay using polyvinyl alcohol (PVF) sponge throughout a year to investigate the effects of season, pregnancy and lactation on the thyroxine level seasonably, the serum thyroxine level was low in summer, and the average level in July and August was 12.6 μg/dl, which was a half of the average winter level in January and February of 26.2 μg/dl. It became low level at the late stage of gestation, showing the lowest value of 13.7 μg/dl just before delivery, and increased suddenly in the second month of lactation attaining the highest level of 27.0 μg/dl. It reduced slightly thereafter to be 22.1 μg/dl at the end of lactation. (Kobatake, H.)

Severe Hypothyroidism due to the Loss of Therapeutic Efficacy of l-Thyroxine in a Patient with Esophageal Complication Associated with Systemic Sclerosis

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Antonio Lobasso

2017-09-01

Full Text Available BackgroundThyroid function abnormalities and thyroid autoantibodies have been frequently described in patients with systemic autoimmune diseases as systemic sclerosis (SSc. Serum TSH levels are higher in SSc patients with more severe skin diseases and a worse modified Rodnan skin score. Asymptomatic esophageal involvement due to SSc has never been described as a cause of severe hypothyroidism due to l-thyroxine (l-T4 malabsorption in patients with Hashimoto’s thyroiditis (HT and SSc.Case reportHere, we report a case of a 56-year-old female affected by both SSc and HT who developed severe hypothyroidism due to the loss of therapeutic efficacy of l-T4. Therapeutic failure resulted from the altered l-T4 absorption because of SSc esophageal complications. Clinical findings improved after the administration of oral liquid l-T4. Thyroid function completely normalized with a full clinical recovery, the disappearance of the pericardial effusion and the improvement of the pulmonary pressure.ConclusionA recognition of a poor absorption is crucial in patients with hypothyroidism and SSc to reduce the risk of the subsequent adverse events. This case suggests the importance of clinical and laboratory surveillance in patients with SSc and HT because the systemic complications of these dysfunctions may worsen the prognosis of hypothyroid SSc/HT patients.

The influence of caloric deprivation and food composition on TSH, thyroid hormones and nuclear binding of T3 in mononuclear blood cells in obese women

DEFF Research Database (Denmark)

Matzen, L E; Kvetny, J

1989-01-01

In vivo changes in thyroid-stimulating hormone (TSH), thyroxin (T4), triiodothyronine (T3) and nuclear binding of T3 (NBT3) in mononuclear blood cells were studied in obese women during seven days of caloric deprivation (maximum 1,100 kcal/d). In seven women given a high protein diet (80% protein...

Effect of magnesium sulfate and thyroxine on inflammatory markers in a rat model of hypothyroidism.

Science.gov (United States)

Abbas, Amr M; Sakr, Hussein F

2016-04-01

Inflammation is a major risk factor for cardiovascular complications. Magnesium sulfate (MgSO4) has anti-inflammatory actions. Therefore we investigated the effects of levothyroxine and MgSO4 on inflammatory markers as C-reactive protein (CRP), interleukin-6, tumor necrosis factor-α (TNF-α), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) in hypothyroid rats. Sixty male rats were divided into 6 groups; normal, normal + MgSO4, hypothyroidism, hypothyroidism + levothyroxine, hypothyroidism + MgSO4, and hypothyroidism + levothyroxine + MgSO4. Thyroxine, triiodothyronine, and thyroid-stimulating hormone (TSH), CRP, interleukin-6, TNF-α, ICAM-1, and VCAM-1 were measured in all rats. Hypothyroidism significantly increased TSH, CRP, interleukin-6, TNF-α, ICAM-1, and VCAM-1 and decreased triiodothronine and thyroxine. Treatment of hypothyroid rats with levothyroxine or MgSO4 significantly decreased CRP, interleukin-6, TNF-α, ICAM-1, and VCAM-1. Combined therapy of hypothyroid rats with levothyroxine and MgSO4 significantly decreased CRP, interleukin-6, TNF-α, ICAM-1, and VCAM-1 compared with hypothyroid rats either untreated or treated with levothyroxine or MgSO4. This study demonstrates that hypothyroid rats have chronic low grade inflammation, which may account for increased risk of cardiovascular diseases. Combined levothyroxine and MgSO4 is better than levothyroxine or MgSO4 alone in alleviating the chronic low grade inflammatory status and therefore reducing the risk of cardiovascular diseases in hypothyroid animals.

Effect of protein and protein-free energy intake on plasma concentrations of insulin-like growth factor I and thyroid hormones in preruminant calves

NARCIS (Netherlands)

Gerrits, W.J.J.; Decuypere, E.; Verstegen, M.W.A.; Karabinas, V.

1998-01-01

We conducted two experiments with preruminant calves weighing 80 to 240 kg to study the long-term nutritional regulation of circulating IGF-I, thyroxine (T4), and triiodothyronine (T3). The two experiments were similar in design but were performed with calves of two live weight ranges: 80 to 160 kg

Unconventional Pro-inflammatory CD4+ T Cell Response in B Cell-Deficient Mice Infected with Trypanosoma cruzi

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Melisa Gorosito Serrán

2017-11-01

Full Text Available Chagas disease, caused by the parasite Trypanosoma cruzi, is endemic in Latin America but has become a global public health concern by migration of infected people. It has been reported that parasite persistence as well as the intensity of the inflammatory immune response are determinants of the clinical manifestations of the disease. Even though inflammation is indispensable for host defense, when deregulated, it can contribute to tissue injury and organ dysfunction. Here, we report the importance of B cells in conditioning T cell response in T. cruzi infection. Mice deficient in mature B cells (muMT mice infected with T. cruzi exhibited an increase in plasma TNF concentration, TNF-producing CD4+ T cells, and mortality. The increase in TNF-producing CD4+ T cells was accompanied by a reduction in IFNγ+CD4+ T cells and a decrease of the frequency of regulatory Foxp3+, IL-10+, and IL17+CD4+ T cells populations. The CD4+ T cell population activated by T. cruzi infection, in absence of mature B cells, had a high frequency of Ly6C+ cells and showed a lower expression of inhibitory molecules such as CTLA-4, PD-1, and LAG3. CD4+ T cells from infected muMT mice presented a high frequency of CD62LhiCD44− cells, which is commonly associated with a naïve phenotype. Through transfer experiments we demonstrated that CD4+ T cells from infected muMT mice were able to condition the CD4+ T cells response from infected wild-type mice. Interestingly, using Blimp-flox/flox-CD23icre mice we observed that in absence of plasmablast/plasma cell T. cruzi-infected mice exhibited a higher number of TNF-producing CD4+ T cells. Our results showed that the absence of B cells during T. cruzi infection affected the T cell response at different levels and generated a favorable scenario for unconventional activation of CD4+ T cell leading to an uncontrolled effector response and inflammation. The product of B cell differentiation, the plasmablast/plasma cells, could be able

Relaxivity of Ferumoxytol at 1.5 T and 3.0 T.

Science.gov (United States)

Knobloch, Gesine; Colgan, Timothy; Wiens, Curtis N; Wang, Xiaoke; Schubert, Tilman; Hernando, Diego; Sharma, Samir D; Reeder, Scott B

2018-05-01

The aim of this study was to determine the relaxation properties of ferumoxytol, an off-label alternative to gadolinium-based contrast agents, under physiological conditions at 1.5 T and 3.0 T. Ferumoxytol was diluted in gradually increasing concentrations (0.26-4.2 mM) in saline, human plasma, and human whole blood. Magnetic resonance relaxometry was performed at 37°C at 1.5 T and 3.0 T. Longitudinal and transverse relaxation rate constants (R1, R2, R2*) were measured as a function of ferumoxytol concentration, and relaxivities (r1, r2, r2*) were calculated. A linear dependence of R1, R2, and R2* on ferumoxytol concentration was found in saline and plasma with lower R1 values at 3.0 T and similar R2 and R2* values at 1.5 T and 3.0 T (1.5 T: r1saline = 19.9 ± 2.3 smM; r1plasma = 19.0 ± 1.7 smM; r2saline = 60.8 ± 3.8 smM; r2plasma = 64.9 ± 1.8 smM; r2*saline = 60.4 ± 4.7 smM; r2*plasma = 64.4 ± 2.5 smM; 3.0 T: r1saline = 10.0 ± 0.3 smM; r1plasma = 9.5 ± 0.2 smM; r2saline = 62.3 ± 3.7 smM; r2plasma = 65.2 ± 1.8 smM; r2*saline = 57.0 ± 4.7 smM; r2*plasma = 55.7 ± 4.4 smM). The dependence of relaxation rates on concentration in blood was nonlinear. Formulas from second-order polynomial fittings of the relaxation rates were calculated to characterize the relationship between R1blood and R2 blood with ferumoxytol. Ferumoxytol demonstrates strong longitudinal and transverse relaxivities. Awareness of the nonlinear relaxation behavior of ferumoxytol in blood is important for ferumoxytol-enhanced magnetic resonance imaging applications and for protocol optimization.

Disparate effects of heparin on free thyroxine measured by two different radioimmunoassays

International Nuclear Information System (INIS)

McDougall, I.R.; Bayer, M.F.; Nierenberg, D.; Lewis, S.J.

1983-01-01

Heparin causes a rise in free thyroxine (FT4) measured by equilibrium dialysis (E.D.). With the introduction of at least 4 commercial radioimmunoassays (RIA) for FT4, FT4 measurements have become accepted as one of the best routine thyroid function tests. Investigators have indicated that FT4 levels determined by RIA may be of particular value in patients hospitalized for various severe nonthyroidal illnesses in whom conventional thyroid function tests tend to be abnormal. However, very little information is as yet available on possible effects of various drugs on FT4 levels measured by these new methods. A study was undertaken to evaluate the effect of heparin on FT4 measured by 2 different RIA procedures: RIA-I, GammaCoat FT4 by clinical Assays and RIA-II, Amerlex FT4 by Amersham

Effects of In Utero Thyroxine Exposure on Murine Cranial Suture Growth.

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R Nicole Howie

Full Text Available Large scale surveillance studies, case studies, as well as cohort studies have identified the influence of thyroid hormones on calvarial growth and development. Surveillance data suggests maternal thyroid disorders (hyperthyroidism, hypothyroidism with pharmacological replacement, and Maternal Graves Disease are linked to as much as a 2.5 fold increased risk for craniosynostosis. Craniosynostosis is the premature fusion of one or more calvarial growth sites (sutures prior to the completion of brain expansion. Thyroid hormones maintain proper bone mineral densities by interacting with growth hormone and aiding in the regulation of insulin like growth factors (IGFs. Disruption of this hormonal control of bone physiology may lead to altered bone dynamics thereby increasing the risk for craniosynostosis. In order to elucidate the effect of exogenous thyroxine exposure on cranial suture growth and morphology, wild type C57BL6 mouse litters were exposed to thyroxine in utero (control = no treatment; low ~167 ng per day; high ~667 ng per day. Thyroxine exposed mice demonstrated craniofacial dysmorphology (brachycranic. High dose exposed mice showed diminished area of the coronal and widening of the sagittal sutures indicative of premature fusion and compensatory growth. Presence of thyroid receptors was confirmed for the murine cranial suture and markers of proliferation and osteogenesis were increased in sutures from exposed mice. Increased Htra1 and Igf1 gene expression were found in sutures from high dose exposed individuals. Pathways related to the HTRA1/IGF axis, specifically Akt and Wnt, demonstrated evidence of increased activity. Overall our data suggest that maternal exogenous thyroxine exposure can drive calvarial growth alterations and altered suture morphology.

Effects of In Utero Thyroxine Exposure on Murine Cranial Suture Growth.

Science.gov (United States)

Howie, R Nicole; Durham, Emily L; Black, Laurel; Bennfors, Grace; Parsons, Trish E; Elsalanty, Mohammed E; Yu, Jack C; Weinberg, Seth M; Cray, James J

2016-01-01

Large scale surveillance studies, case studies, as well as cohort studies have identified the influence of thyroid hormones on calvarial growth and development. Surveillance data suggests maternal thyroid disorders (hyperthyroidism, hypothyroidism with pharmacological replacement, and Maternal Graves Disease) are linked to as much as a 2.5 fold increased risk for craniosynostosis. Craniosynostosis is the premature fusion of one or more calvarial growth sites (sutures) prior to the completion of brain expansion. Thyroid hormones maintain proper bone mineral densities by interacting with growth hormone and aiding in the regulation of insulin like growth factors (IGFs). Disruption of this hormonal control of bone physiology may lead to altered bone dynamics thereby increasing the risk for craniosynostosis. In order to elucidate the effect of exogenous thyroxine exposure on cranial suture growth and morphology, wild type C57BL6 mouse litters were exposed to thyroxine in utero (control = no treatment; low ~167 ng per day; high ~667 ng per day). Thyroxine exposed mice demonstrated craniofacial dysmorphology (brachycranic). High dose exposed mice showed diminished area of the coronal and widening of the sagittal sutures indicative of premature fusion and compensatory growth. Presence of thyroid receptors was confirmed for the murine cranial suture and markers of proliferation and osteogenesis were increased in sutures from exposed mice. Increased Htra1 and Igf1 gene expression were found in sutures from high dose exposed individuals. Pathways related to the HTRA1/IGF axis, specifically Akt and Wnt, demonstrated evidence of increased activity. Overall our data suggest that maternal exogenous thyroxine exposure can drive calvarial growth alterations and altered suture morphology.

Features of selenium metabolism in humans living under the conditions of North European Russia.

Science.gov (United States)

Parshukova, Olga; Potolitsyna, Natalya; Shadrina, Vera; Chernykh, Aleksei; Bojko, Evgeny

2014-08-01

Selenium supplementation and its effects on Northerners have been little studied. The aim of our study was to assess the selenium levels of the inhabitants of North European Russia, the seasonal aspects of selenium supplementation, and the interrelationships between selenium levels and the levels of thyroid gland hormones. To study the particular features of selenium metabolism in Northerners over the course of 1 year, 19 healthy male Caucasian volunteers (18-21 years old) were recruited for the present study. The subjects were military guards in a Northern European region of Russia (Syktyvkar, Russia, 62°N latitude) who spent 6-10-h outdoors daily. The study was conducted over a 12-month period. Selenium levels, glutathione peroxidase (GP) activity, as well as total triiodothyronine (T3), total thyroxin (T4), free thyroxin, free triiodothyronine, and thyrotropin (TSH) levels, were determined in the blood serum. The study subjects showed low levels of plasma selenium throughout the year. We observed a noticeable decrease in plasma selenium levels during the period from May to August, with the lowest levels in July. Selenium levels in the military guards correlated with the levels of selenium-dependent GP enzyme activity throughout the year. Additionally, we demonstrated a significant correlation between selenium and pituitary-thyroid axis hormones (total T3, free T4, and TSH) in periods in which plasma selenium levels were lower than the established normal ranges. Over the course of 1 year, low levels of plasma selenium affect GP activity and thyroid hormone levels in humans living in North European Russia.

Plasma Total Homocysteine (tHcy) Levels in Healthy Nigerian ...

African Journals Online (AJOL)

Establishment and stratification of reference values for a laboratory area of practice enhances the test result interpretation and sensitivity. Plasma total homocysteine (tHcy) is a metabolite of methionine which is dependent on vitamin B6, B12 and folate as co-factors. Plasma level (Hyperhomocysteinemia) is influenced by ...

Quality characteristics of chemicals for the radioimmunoassay of thyroxine and thyrotropin.; Caracteristicas de calidad de reactivos para el radioinmunoanalisis de tiroxina y tirotropina.

Energy Technology Data Exchange (ETDEWEB)

Verdeja I, C E

1994-12-31

Radioimmunoassay is a form of saturation analysis in which the test material competes with labelled antigen for a limited amount of antibody, the amount of label displaced being a measure of the antigen in the test sample. In this country, the kits for Radioimmunoassay (RIA) are imported, and this increase the cost of it. Because this lack of production, the National Institute of Nuclear Research (ININ) has developed RIA`s kits for the thyroxine (T{sub 4}), Thyrotropin (TSH) and Triyodotironine (T{sub 3}) hormones. This work presents the conclusions of the test recommended by the WHO. The quality test were: recuperation, cross reactions, basic parameters, intra and inter assay variations, sensibility and others. The results show that the RIA`s kits of the ININ have a good behavior and can be use in the clinical laboratory. (Author).

Serum Levels of Follistatin Are Positively Associated With Serum-Free Thyroxine Levels in Patients With Hyperthyroidism or Euthyroidism

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Tseng, Fen-Yu; Chen, Yen-Ting; Chi, Yu-Chao; Chen, Pei-Lung; Yang, Wei-Shiung

2016-01-01

Abstract Follistatin is a glycoprotein with various biologic functions that plays a role in adipocyte differentiation, muscle stimulation, anti-inflammation, and energy homeostasis. Thyroid hormones influence energy expenditure, glucose, and lipid metabolism. The association between serum follistatin level and thyroid function statuses has seldom been evaluated. The objectives of this study were to compare serum follistatin concentrations in different thyroid function statuses and to evaluate the associations between serum follistatin and free thyroxine (fT4) levels. In this study, 30 patients with hyperthyroidism (HY group) and 30 euthyroid individuals (EU group) were recruited. The patients of HY group were treated with antithyroid regimens as clinically indicated, whereas no medication was given to EU group. The demographic and anthropometric characteristics, biochemical data, serum levels of follistatin, and thyroid function of both groups at baseline and at the 6th month were compared. Data of all patients were pooled for the analysis of the associations between the levels of follistatin and fT4. At baseline, the HY group had significantly higher serum follistatin levels than the EU group (median [Q1, Q3]: 1.81 [1.33, 2.78] vs 1.13 [0.39, 1.45] ng/mL, P hyperthyroidism had higher serum follistatin levels, which decreased after receiving antithyroid treatment. In addition, the serum follistatin concentrations were positively associated with serum fT4 levels in patients with hyperthyroidism or euthyroidism. PMID:26844494

Case report: When measured free T4 and free T3 may be misleading. Interference with free thyroid hormones measurements on Roche® and Siemens® platforms

Directory of Open Access Journals (Sweden)

Lewandowski Krzysztof C

2012-10-01

Full Text Available Abstract A 59-year old female patient presented with apathy and 6 kg weight gain. Investigations revealed severe primary hypothyroidism (TSH>100 μIU/ml. L-thyroxine (L-T4 was started and titrated up to 75 μg, once daily, with clinical improvement. Other investigations revealed very high titres of anti-thyroid peroxidase (anti-TPO and anti-thyroglobulin (anti-Tg antibodies. After three months, there was a fall in TSH to 12.74 μIU/ml, however, with unexpectedly high free T4 (FT4 - 6.8 ng/ml and free T3 (FT3 - 6.7 pg/ml concentrations [reference range (rr: 0.8-1.9 ng/ml and 1.5-4.1 pg/ml (Siemens®, respectively]. At this stage L-T4 was stopped, and this was followed by a rapid increase in TSH (to 77.76 μIU/ml and some decrease in FT4 and FT3, however FT4 concentration remained elevated (2.1 ng/ml. Following this, L-T4 was restarted. On admission to our Department, she was clinically euthyroid on L-T4, 88 μg, once daily. Investigations on Roche® platform confirmed mildly elevated TSH - 5.14 (rr: 0.27-4.2 μIU/ml with high FT4 [4.59 (rr: 0.93-1.7 ng/ml] and FT3 [4.98 (rr: 2.6-4.4 pg/ml] concentrations. Other tests revealed hypoechogenic ultrasound pattern typical for Hashimoto thyroiditis. There was no discrepancy in calculated TSH value following TSH dilution (101% recovery. Concentrations of FT4 and FT3 were assessed on the day of discontinuation of L-T4 and after four days by the means of Abbott® Architect I 1000SR platform. These revealed FT4 and FT3 concentrations within the reference range [e.g., FT4 - 1.08 ng/ml (rr: 0.7-1.48] vs 4.59 ng/ml (rr: 0.93-1.7, Roche®, FT3 - 3.70 pg/ml (rr: 1.71-3.71 vs 4.98 (rr: 2.6-4.4, Roche®], confirming assay interference. Concentrations of ferritin and SHBG were normal. Conclusions Clinicians must be aware of possible assay interference, including the measurements of FT4 and FT3 in the differential diagnosis of abnormal results of thyroid function tests that do not fit the patient clinical

Study on the thyroid function of thoroughbred horses by means of 'in vitro' /sup 125/I-T/sub 3/ modified and /sup 125/I-T/sub 4/ tests

Energy Technology Data Exchange (ETDEWEB)

de Martin, B W [Sao Paulo Univ. (Brazil). Faculdade de Medicina Veterinaria e Zootecnia

1975-01-01

Sera of 71 animals, divided in groups of males and females, in repose and after activity were studied. The method to establish the percentage of the /sup 125/I-lyothyronine retention in resin (Test /sup 125/I-T/sub 3/ or T/sub 3/) was modified by the use of 0.2 ml of serum on the resin column, after addition of the marked hormone. This modification served to prove that thoroughbred equines show binding of the I-lyothyronine to the serum four times reduced, indicating, therefore, that these animals have four times more ligation sites of triidothyronin saturation in the serum, when compared with the results obtained from human beings. The variance analysis applied to the T/sub 3/ Test showed no significant results at the 95% level as regards to activity. For the 71 animals, the author has found an average of 50.30% of the /sup 125/I-Lyothyronine in resin retention, being the confidence interval for this group between 48.75% and 51.85% to a 95% confidence coefficient. Evaluating the results of the T/sub 4/ Test by means of the variance analysis, we noticed that the male and female groups in repose differed statistically from the groups after activity to a 95% confidence coefficient. The author has grouped the results of the T/sub 4/ Test of 32 equines, 18 males and 14 females, in repose, obtaining an average of 0.61 mcg and 0.51 mcg and 0.71 mcg T/sub 4//100 ml as confidence interval to a 95% confidence coefficient. We have listed 39 results of T/sub 4/ Test, being 23 males and 61 Females, after activity, obtaining an average of 2.01 mcg of thyroxin by 100 ml of serum and 1.72 mcg and 2.30 T/sub 4//100 ml as confidence interval to a 95% confidence coefficient.

Endothelin mechanisms in altered thyroid states in the rat.

Science.gov (United States)

Rebello, S; Thompson, E B; Gulati, A

1993-06-11

Endothelin (ET) and its receptor characteristics were studied in hyper- and hypo-thyroid states in the rats. Hyperthyroidism was induced by daily administration of thyroxine (0.1 mg/kg i.p.) for 8 weeks, while hypothyrodism was induced by daily administration of methimazole (10 mg/kg i.p.) for 8 weeks. The chronic administration of thyroxine to rats decreased their rate of gain of body weight, increased serum T3 and T4 concentration, blood pressure and heart rate. The chronic administration of methimazole decreased the rate of gain of body weight, serum T3 and T4 concentration, blood pressure and heart rate as compared to vehicle-treated control. Plasma ET-1 levels were found to be similar in control and methimazole-treated rats, while the levels were found to be significantly (P < 0.002) increased in thyroxine-treated rats as compared to control rats. Binding studies showed that [125I]ET-1 bound to a single, high affinity binding site in the cerebral cortex, hypothalamus and pituitary. The density (Bmax) and the affinity (Kd) of [125I]ET-1 binding in the cerebral cortex and hypothalamus were found to be similar in control, methimazole- and thyroxine-treated rats. The pituitary of thyroxine-treated rats showed a decrease in the binding (34.3% decrease in the density) of [125I]ET-1 as compared to control rats. No difference was observed in the binding of [125I]ET-1 to pituitary membranes from control and methimazole-treated rats. Competition studies showed that the IC50 and Ki values of ET-3 for [125]ET-1 binding were about 8 to 11 times higher than ET-1 in cerebral cortex, hypothalamus and pituitary.(ABSTRACT TRUNCATED AT 250 WORDS)

IgE actions on CD4+ T cells, mast cells, and macrophages participate in the pathogenesis of experimental abdominal aortic aneurysms

DEFF Research Database (Denmark)

Wang, Jing; Lindholt, Jes S; Sukhova, Galina K

2014-01-01

Immunoglobulin E (IgE) activates mast cells (MCs). It remains unknown whether IgE also activates other inflammatory cells, and contributes to the pathogenesis of abdominal aortic aneurysms (AAAs). This study demonstrates that CD4+ T cells express IgE receptor FcεR1, at much higher levels than do CD......8+ T cells. IgE induces CD4+ T-cell production of IL6 and IFN-γ, but reduces their production of IL10. FcεR1 deficiency (Fcer1a-/-) protects apolipoprotein E-deficient (Apoe-/-) mice from angiotensin-II infusion-induced AAAs and reduces plasma IL6 levels. Adoptive transfer of CD4+ T cells (but...... with AAAs had significantly higher plasma IgE levels than those without AAAs. This study establishes an important role of IgE in AAA pathogenesis by activating CD4+ T cells, MCs, and macrophages and supports consideration of neutralizing plasma IgE in the therapeutics of human AAAs....

Elevated serum free thyroxine by thyroxine analog radioimmunoassays in euthyroid patients with familial dysalbuminemic hyperthyroxinemia

International Nuclear Information System (INIS)

Rajatanavin, R.; Fournier, L.; DeCosimo, D.; Abreau, C.; Braverman, L.E.

1982-01-01

A study was done to ascertain whether the serum free T4 measured by free T4 radioimmunoassay kits would, like equilibrium dialysis, be normal in patients with familial dysalbuminemic hyperthyroxinemia. Five free T4 radioimmunoassay kits were used to measure free T4 in serum samples from 19 patients with familial dysalbuminemic hyperthyroxinemia and 20 healthy volunteers. Values (mean +/- SE) for T4, free T4 index, and free T4 (equilibrium dialysis) in these normal subjects and patients with familial dysalbuminemic hyperthyroxinemia, respectively, were as follows: T4, 8.1 +/- 0.2 and 18.3 +/- 0.7 μg/dL; free T4 index, 3.1 +/- 0.1 and 7.3 +/- 0.3 μg/dL; free T4, 1.4 +/- 0.1 and 1.2 +/- 0.1 ng/dL. The following free T4 radioimmunoassay methods were used: antibody coated microfine silica, microencapsulated antibody, two-step antibody-coated tube, and one-step 125 I-T4 analog (2 kits). The present findings in patients with familial dysalbuminemic hyperthyroxinemia and previous observations in ill euthyroid patients suggest that serum free T4 measured by some radioimmunoassay methods must be interpreted with caution in these two clinical situations

Global skeletal uptake of technetium-99m methylene diphosphonate in female patients receiving suppressive doses of L-thyroxine for differentiated thyroid cancer

International Nuclear Information System (INIS)

Frusciante, V.; Dicembrino, F.; Carnevale, V.; Scillitani, A.; Zingrillo, M.; Ghiggi, M.R.; Giannatempo, G.M.; Minisola, S.

1998-01-01

This study was carried out in order to investigate the possible detrimental effects on bone of levothyroxine (l-T 4 ) suppressive therapy in female patients who had undergone surgery for differentiated thyroid cancer (DTC). Twenty female (14 premenopausal and 6 postmenopausal) patients receiving l-T 4 suppressive therapy for DTC were studied. The sample was selected in such a way as to avoid factors influencing bone metabolism other than l-T 4 . All patients were monitored by sensitive thyroid-stimulating hormone, free triiodothyronine and free thyroxine assays throughout the follow-up. Nineteen healthy (12 premenopausal and 7 postmenopausal) matched women served as controls. In all subjects bone turnover was evaluated by the measurement of global skeletal uptake of technetium-99m methylene diphosphonate (GSU); bone mineral density (BMD) was measured by quantitative computed tomography at the lumbar spine (LS) and by dual-energy X-ray absorptiometry both at the LS and at three femoral sites: the femoral neck, Ward's triangle and the greater trochanter. No significant difference was found in either GSU or BMD between patients (treated for an average period of 68 months) and controls in the whole sample or in any subgroup. Furthermore, no correlations were found between either GSU or BMD and the duration of therapy, daily doses of l-T 4 or results of thyroid function tests. Our data show that carefully monitored l-T 4 therapy does not influence skeletal turnover (directly reflected by GSU) or the bone density of the spine and femur. (orig.)

Global skeletal uptake of technetium-99m methylene diphosphonate in female patients receiving suppressive doses of L-thyroxine for differentiated thyroid cancer

Energy Technology Data Exchange (ETDEWEB)

Frusciante, V.; Dicembrino, F. [Department of Nuclear Medicine, Ospedale ``Casa Sollievo della Sofferenza``, IRCCS di San Giovanni Rotondo (Italy); Carnevale, V. [Division of Internal Medicine, Ospedale ``Casa Sollievo della Sofferenza``, IRCCS di San Giovanni Rotondo (Italy); Scillitani, A.; Zingrillo, M.; Ghiggi, M.R. [Division of Endocrinology, Ospedale ``Casa Sollievo della Sofferenza``, IRCCS di San Giovanni Rotondo (Italy); Giannatempo, G.M. [Department of Radiology, Ospedale ``Casa Sollievo della Sofferenza``, IRCCS di San Giovanni Rotondo (Italy); Minisola, S. [Istituto di II Clinica Medica, Universita degli Studi di Roma ``La Sapienza``, Rome (Italy)

1998-02-01

This study was carried out in order to investigate the possible detrimental effects on bone of levothyroxine (l-T{sub 4}) suppressive therapy in female patients who had undergone surgery for differentiated thyroid cancer (DTC). Twenty female (14 premenopausal and 6 postmenopausal) patients receiving l-T{sub 4} suppressive therapy for DTC were studied. The sample was selected in such a way as to avoid factors influencing bone metabolism other than l-T{sub 4}. All patients were monitored by sensitive thyroid-stimulating hormone, free triiodothyronine and free thyroxine assays throughout the follow-up. Nineteen healthy (12 premenopausal and 7 postmenopausal) matched women served as controls. In all subjects bone turnover was evaluated by the measurement of global skeletal uptake of technetium-99m methylene diphosphonate (GSU); bone mineral density (BMD) was measured by quantitative computed tomography at the lumbar spine (LS) and by dual-energy X-ray absorptiometry both at the LS and at three femoral sites: the femoral neck, Ward`s triangle and the greater trochanter. No significant difference was found in either GSU or BMD between patients (treated for an average period of 68 months) and controls in the whole sample or in any subgroup. Furthermore, no correlations were found between either GSU or BMD and the duration of therapy, daily doses of l-T{sub 4} or results of thyroid function tests. Our data show that carefully monitored l-T{sub 4} therapy does not influence skeletal turnover (directly reflected by GSU) or the bone density of the spine and femur. (orig.) With 1 fig., 2 tabs., 36 refs.

An Evaluation of Thyroid Hormones (T4, T3, and Free T4) Concentrations During Pregnancy

International Nuclear Information System (INIS)

Lee, Kyu Bo; Kim, Ji Yeul

1981-01-01

Serum concentrations of T 4 , T 3 , and free T 4 were measured by radioimmunoassay in normal pregnant women at trimesters, in postpartum women, and cord blood of neonate. Total T 4 were increased during pregnancy, remarkably high in the first trimester, and also somewhat increased in postpartum, and normal in neonate. Total T 3 were in normal range during pregnancy, but increased in postpartum, whereas decreased in neonate. Free T 4 were decreased in 2nd and 3rd trimesters of pregnancy, however normal in postpartum and neonate.

Radioimmunoassay methods for the determination of L-triiodo-thyronine and thyroxine

International Nuclear Information System (INIS)

1976-01-01

An improved, simplified radioimmunoassay method for the in vitro determination of L-triiodo-thyronine in unextracted blood serum is described which involves the use of a combination reagent constituted by a buffered solution containing radioactive L-triiodothyronine and an inhibitor for inhibiting the binding of L-triiodothyronine to thyroxine-binding globulin. Optionally the reagent may also include an antiserum containing an antibody capable of immunoreactivity with L-triiodothyronine. Packaged test kits for use in conveniently carrying out the radioimmunoassay are also provided. Certain salts of 8-anilino-1-naphtalene sulfonic acid, which may be regarded as purified forms of the acid, are preferably employed as inhibitors for inhibiting binding of L-triiodothyronine to thyroxine-binding globulin