Main Factors Involved in Thyroid Hormone Action

The thyroid hormone receptors are the mediators of a multitude of actions by the thyroid hormones in cells. Most thyroid hormone activities require interaction with nuclear receptors to bind DNA and regulate the expression of target genes. In addition to genomic regulation, thyroid hormones function via activation of specific cytosolic pathways, bypassing interaction with nuclear DNA. In the present work, we reviewed the most recent literature on the characteristics and roles of different factors involved in thyroid hormone function in particular, we discuss the genomic activity of thyroid hormone receptors in the nucleus and the functions of different thyroid hormone receptor isoforms in the cytosol. Furthermore, we describe the integrin αvβ3-mediated thyroid hormone signaling pathway and its rapid nongenomic action in the cell. We furthermore reviewed the thyroid hormone transporters enabling the uptake of thyroid hormones in the cell, and we also include a paragraph on the proteins that mediate thyroid receptors’ shuttling from the nucleus to the cytosol.     

Clinical use of laboratory thyroid tests and investigations.

Laboratory thyroid testing involves in vitro tests for autoimmune thyroid disease, thyroid dysfunction and neoplasia, in vivo investigations of thyroid function, and investigations of thyroid morphology. The authors describe, in tabular form, the diagnostic information carried by the tests and their clinical utility as well as clinically relevant interferences.     

声速匹配技术对甲状腺癌的诊断价值

本研究的目的是分析声速匹配技术对甲状腺癌的诊断价值。选取了159例甲状腺病变患者设为甲状腺病变组,健康志愿者40例设为甲状腺正常组,行声速匹配技术检查,分析特征并对比ZSI值,评估了声速匹配技术对甲状腺癌的诊断价值。结果显示,甲状腺癌组ZSI值较高(P<0.05)。ZSI值预测甲状腺癌的ROC曲线下面积(AUC)为0.867(0.729~1.004),灵敏度为86.67%,特异度为60.00%,似然比为2.167,ZSI值临界值为50.42 m/s。预后不良组甲状腺癌患者ZSI值高于预后良好组(P<0.05)。由本文结果可知声速匹配技术对不同类型甲状腺癌的诊断准确性均较高,可准确测出患者甲状腺声速值,稳定性良好,可用于临床甲状腺癌的诊断和预后预测。     

Thyroid hormone synthesis and anti-thyroid drugs: A bioinorganic chemistry approach

Hydrogen peroxide, generated by thyroid oxidase enzymes, is a crucial substrate for the thyroid peroxidase (TPO)-catalysed biosynthesis of thyroid hormones, thyroxine (T4) and triiodothyronine (T3) in the thyroid gland. It is believed that the H₂O₂ generation is a limiting step in thyroid hormone synthesis. Therefore, the control of hydrogen peroxide concentration is one of the possible mechanisms for the inhibition of thyroid hormone biosynthesis. The inhibition of thyroid hormone synthesis is required for the treatment of hyperthyroidism and this can be achieved by one or more anti-thyroid drugs. The most widely used anti-thyroid drug methimazole (MMI) inhibits the production of thyroid hormones by irreversibly inactivating the enzyme TPO. Our studies show that the replacement of sulphur in MMI by selenium leads to a selone, which exists predominantly in its zwitterionic form. In contrast to the sulphur drug, the selenium analogue (MSeI) reversibly inhibits the peroxidase-catalysed oxidation and iodination reactions. Theoretical studies on MSeI reveal that the selenium atom in this compound carries a large negative charge. The carbon-selenium bond length in MSeI is found to be close to single-bond length. As the selenium atom exhibits a large nucleophilic character, the selenium analogue of MMI may scavenge the hydrogen peroxide present in the thyroid cells, which may lead to a reversible inhibition of thyroid hormone biosynthesis.     

Diagnosis of cold thyroid nodules by 201T1 scientigraphy

Fifty two patients with cold thyroid nodule demonstrated on the thyroid scan were imaged with 201Tl which were given intravenously as thallium chloride in dose of 2 mCi. Thirty nine of 52 patients were confirmed and investigated whether 201Tl concentrated or not. Fourteen of 15 (93 percent) thyroid carcinomas, 5 of 17 (29 percent) thyroid adenomas, 1 of 2 adenomatous goiters and all of 5 of chronic thyroiditis were visualized as positive with 201 Tl. One thyroid carcinoma did not concentrate 201Tl which was confirmed to have cystic degeneration. Of the 19 benign cold thyroid nodules except chronic thyroiditis 6 were positively visualized with 201Tl. However, 201Tl did not accumulate in the other 13 benign nodules, 11 out of which were confirmed to have cystic degeneration. The data suggests that if the thyroid nodule is found to have negative accumulation of 201Tl, malignancy can be ruled out except a small microscopical lesion.     

The investigation of thyroid function.

The measurement of thyrotropin (TSH) by a third-generation assay (functional sensitivity 0.01-0.02 mU/L) offers the single best test of assessing thyroid status and is more cost effective than measurement of thyroxine (T4) as a first-line test. However, in certain situations, e.g., nonthyroidal illness (NTI), secondary thyroid disease, early treatment of hyperthyroidism, early pregnancy, and heterophilic antibody interference, TSH alone may be misleading, and thyroid hormone measurements are also required. The author's laboratory has found that the measurement of TSH together with free thyroxine (by a nonanalogue method) offers the most speedy and effective first-line strategy for thyroid function testing. Abnormalities in thyroid function tests in euthyroid patients are most likely found in NTI and the elderly. For this reason, thyroid function tests (TFTs) should not be requested in elderly or hospitalized patients unless the presenting complaint is considered to be because of a thyroid problem.     

硒与甲状腺疾病

简要介绍了硒的代谢、功能及其与甲状腺的生理，重点综述了硒在几种常见甲状腺疾病中的表达水平，并探讨了硒对甲状腺疾病的作用机制。     

Isotopic ratios of129I/127I in mammalian thyroid glands in Japan

The isotopic ratios of¹²⁹I/¹²⁷I in cattle thyroid glands collected from various areas of Japan were measured by neutron activation analysis with combustion pre-treatment. Pig and human thyroid glands were also analyzed by the same method. The iodine isotopic ratio in cattle thyroid glands in Japan is comparable with that observed in Europe. The isotopic ratio in human thyroid glands in Japan is remarkably lower than that in Europe, which has been reported to be comparable to that of cattle. The isotopic ratio in pig thyroid glands is also lower than that in cattle.     

碘的生物无机化学研究进展—碘对甲状腺激素生物活性的结构作用探讨

本文综述甲状腺激素相关研究的进展 ,探讨碘在甲状腺激素与细胞内激素受体蛋白结合中的结构作用。文中评述了关于甲状腺激素与血浆运载蛋白和细胞内受体蛋白结合的溶液亲合性、结构研究和甲状腺激素碘代酚环的分子识别特性与碘的结构效应模拟研究的数据结果 ,并就碘对激素 受体蛋白结合的结构作用提出了作者的观点     

高频超声联合彩色多普勒超声对甲状腺良/恶性结节的诊断价值

本文探讨了高频超声联合彩色多普勒超声对甲状腺结节良/恶性的诊断价值。选择疑似甲状腺结节患者82例作为研究对象,本研究比较了高频超声和彩色多普勒超声与术后病理结果的差异;绘制了ROC曲线,分析了高频超声联合彩色多普勒超声对甲状腺结节良/恶性的诊断效能。结果发现,病理学检查与高频超声联合彩色多普勒超声检查相比较,差异不具有统计学意义(P>0.05);高频超声能够通过结节结构、回声、形态、边缘和钙化灶等特征来区分甲状腺良性与恶性结节;ROC曲线分析结果表明,高频超声联合彩色多普勒超声诊断甲状腺良/恶性结节的曲线下面积(AUC)最高(0.920);高频超声的特异性最高(98.33%);彩色多普勒超声的敏感性最高(86.36%)。本研究证实,高频超声联合彩色多普勒超声可有效提高对甲状腺良/恶性结节的诊断准确性。     

碘的生物无机化学研究进展—碘对甲状腺激素生物活性的结构作用探讨

本文综述甲状腺激素相关研究的进展,探讨碘在甲状腺激素与细胞内激素受体蛋白结合中的结构作用。文中评述了关于甲状腺激素与血浆运载蛋白和细胞内受体蛋白结合的溶液亲合性、结构研究和甲状腺激素碘代酚环的分子识别特性与碘的结构效应模拟研究的数据结果,并就碘对激素受体蛋白结合的结构作用提出了作者的观点。     

中红外光纤光谱法用于甲状腺肿物的体表、 在体及离体检测研究

本文对一些甲状腺患者的肿瘤组织分别进行了体表、术中在体和离体光谱检测研究,探讨了中红外光纤光谱法对甲状腺肿瘤进行无创体表检测的可能性,对术中红外光谱快速判断组织良恶性的规律性进行了系统研究.     

Models for the binding of amiodarone to the thyroid hormone receptor

Summary The antiarrhythmic drug amiodarone has recently been characterized as the first known thyroid hormone antagonist. Its mode of interaction with the thyroid hormone receptor is therefore of interest. A computational analysis of the conformational flexibility of amiodarone using molecular mechanics and the semiempirical molecular orbital method AM1 has been performed. The molecular mechanics studies show that the low-energy conformations of the benzoylbenzofuran portion of amiodarone can be grouped into 4 distinct classes, while the diethylaminoethoxy side chain is extremely flexible. Conformers representative of the 4 low-energy classes were fitted to an extended thyroid hormone receptor model. Four independent modes in which amiodarone could bind to the thyroid hormone receptor site were evaluated.     

对比超声剪切波弹性成像与核素SPECT显像对甲状腺癌的诊断价值

目的探讨超声剪切波弹性成像与核素同核素SPECT显像在甲状腺诊断中的应用价值。方法选取甲状腺疾病患者43例(62个甲状腺结节)为研究对象,分别行核素SPECT显像及超声剪切波弹性成像检查,对比两种检查结果。结果剪切波弹性成像的灵敏度为90.48%,特异度80.49%,准确率为83.87%,核素SPECT显像分别为61.90%、65.82%、66.13%,差异均有统计学意义(P<0.05)。结论在甲状腺癌诊断中,超声剪切波弹性成像临床价值较核素SPECT显像高,更值得推广。     

The concentration of 131I in the thyroid glands of domestic animals

Iodine-131 concentrations in thyroid glands of cows, oxen and swine carried in the Yokohama slauterhouse were measured. The gamma-ray spectral analysis was done with a Ge(Li) detecter. It is considered that 131I in thyroid glands of domestic animals resulted from Chinese open-air nuclear tests and radioactive materials used at medical facilities. It is presumed that 131I from medical facilities was taken in swine thyroid glands from the leaving of meals of patients.     

科学补碘:消除碘缺乏病的成败关键

碘对甲状腺功能具有双向作用,在消除碘缺乏病的同时,切不可忽略全民食盐加碘后高碘甲状腺病的防治。分别从水碘和尿碘两个方面论述了碘与甲状腺病之间的双向关系,并根据流行病学调查数据和全国碘缺乏病监测数据确定了盐碘与尿碘之间的数学关系,计算了食盐碘含量的最适宜范围,提出了下调食盐碘含量、设计区域化碘盐和补碘个性化的科学补碘新策略。     

Noninvasive Surface Detection of Papillary Thyroid Carcinoma by Fourier Transform Infrared Spectroscopy

Previously Fourier transform infrared(FTIR) spectroscopy has been applied to detecting thyroid cancer during operations and to discriminating cervical metastatic ones from non-metastatic lymph nodes. This study explored the possibility of establishing a sensitive, accurate and noninvasive screen or diagnosis by preoperative FTIR spectroscopy. 111 patients undergone a thyroid operation and 50 healthy volunteers were enrolled in the study. The FTIR spectra were obtained by two mid-infrared optical fibers with an attenuated total reflectance(ATR) probe closely contacting the subjects' skin on the thyroid nodules. The FTIR spectra obtained from normal thyroid, nodular goiter(NG) and papillary thyroid carcinoma(PTC) patients were compared. A Fisher's discriminant analysis was created based on these data. There were 41 PTC patients and 70 NG patients according to their histopathological examinations. A total of 23(of 39) parameters were statistically different among the three groups(P<0.05). The F₁₃₀₀ and F₁₀₈₀ parameters were significantly different between the three groups. In total, 9 out of 39 FTIR parameters were selected as independent factors by the Wilks' lambda stepwise discriminant analysis. The discrimination accuracy of papillary thyroid carcinoma in the three groups was 88.8%. Surface detection of PTC by FTIR spectroscopy is feasible. FTIR spectroscopy can be used for rapid and noninvasive PTC screen and auxiliary diagnosis.     

Factors affecting the serum thyroid hormone concentration during fasting in rats--with special reference to the relation with temperature

The present studies examine the effect of starvation together with cold or hot exposure on thyroid hormone levels in rats. At 23 degrees C starved for 5 days, serum thyroid hormone levels decreased significantly compared with fed rats, averaging 3.6 +/- 0.5 micrograms/dl of thyroxine (T4), 47 +/- 11 ng/dl of triiodothyronine (T3), 1.4 +/- 0.3 ng/dl of free T4 and 39.6 +/- 5.1 pg/ml of reverse T3, respectively. At 15 degrees C rats starved for 5 days, serum free T4 level significantly more increased than that of 23 degrees C starved rats, while serum T4 level and T3 did not increase significantly. At 30 degrees C rats whether concomitant starvation or not, serum thyroid hormone levels of both group markedly more decreased than control rats. These experiment provide additional evidence that thyroid gland and the peripheral metabolism of thyroid hormone respond to variety situations such as cold or hot exposure together with starvation or not.     

The Synthesis of 13C9-15N-Labeled 3,5-Diiodothyronine and Thyroxine

Thyroid hormones undergo extensive metabolism to regulate hormone activity. A labeled thyroid hormone would be useful to track hormone metabolism through various pathways. While radiolabeled thyroid hormones have been synthesized and used for in vivo studies, a stable isotope labeled form of thyroid hormone is required for studying thyroid hormone metabolism by LC-MS/MS, an analytical technique that has certain advantages without the complications of radioactivity. Here we report the synthesis of ¹³C₉-¹⁵N-T₂ and ¹³C₉-¹⁵N-T₄, two labeled thyroid hormone derivatives suitable for in vivo LC-MS/MS studies.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

Variation of counting efficiency in determination of 131I activity in the thyroid gland as a result of its position relative to the detector

The appropriate determination of the ¹³¹I which was absorbed into the human body, especially by thyroid, depends not only on individual features of each measurement subjects but also on reproducibility of their position or the thyroid’s position in the human neck. Possible uncertainties caused by changes of the thyroid position relative to detector were studied in a series of measurements. The research has shown that the dispersion of the results can reach up even to the level of 50 %.