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Anatomy and Physiology of Head and Neck Endocrine Glands
Published in R James A England, Eamon Shamil, Rajeev Mathew, Manohar Bance, Pavol Surda, Jemy Jose, Omar Hilmi, Adam J Donne, Scott-Brown's Essential Otorhinolaryngology, 2022
The thyroid produces two thyroid hormones, tetraiodothyronine (T4) and triiodothyronine (T3). Eighty percent of production comprises T4. T4 is converted to T3 in the peripheral circulation. T3 is more biologically active, with a fivefold greater potency and a shorter half-life (1.5 days for T3 vs 7 days for T4). Serum T3 and T4 concentrations are maintained peripherally by plasma thyroxine-binding globulins, with only a small volume of free hormones available to stimulate physiological effects.
Teace Elements in Parenteral Nutrition*
Published in Fima Lifshitz, Childhood Nutrition, 2020
Adib A. Moukarzel, Marvin E. Ament
Iodine is of importance in the cellular oxidative processes associated with thyroid functions. Its principal role in humans is its incorporation into thyroid hormones (triiodothyronine and thyroxine) that regulate cellular metabolism, temperature, and normal growth. Approximately two-thirds of total body iodine is in the thyroid.
Participation of Cytokines and Growth Factors in Biliary Epithelial Proliferation and Mito-Inhibition during Ductular Reactions
Published in Gianfranco Alpini, Domenico Alvaro, Marco Marzioni, Gene LeSage, Nicholas LaRusso, The Pathophysiology of Biliary Epithelia, 2020
Anthony J. Demetris, J.G. Lunz, Vladimir Subbotin, Tong Wu, Isao Nozaki, Sarah Contrucci, Xia Yin
Administration of triiodothyronine to rats stimulates proliferation of hepatocytes in vivo, a pharmacologically means of stimulating hepatocyte division.150 Oral administration of thyroxine to rats however, was unable to stimulate hepatocyte PCNA labeling, but did increase BEC PCNA labeling.151 In addition, if rats subjected to liver injury from thioacetamide are simultaneously treated with thyroxine, BEC proliferation is greater than that seen in either untreated or thyroxine-treated normal rats. Thus, in vivo, normal BEC seem to be influenced by thyroid hormones, and in the presence of injury, the effect is magnified. Thyroxine is also a common constituent of media used to culture BEC, but no systematic analysis of its effect on BEC growth, in vitro has been undertaken.46,73
Subclinical hypothyroidism, outcomes and management guidelines: a narrative review and update of recent literature
Published in Current Medical Research and Opinion, 2023
Overall, the recent research summarized above has deepened the level of evidence relating to SCH and outcomes but does not alter the conclusions of the 2013/4 ETA guidelines for the management of SCH in adults (summarized in Box 1). Recommendations such as focussing the need for LT4 treatment primarily on subjects with TSH >10 mIU/L (and considering LT4 for younger (≤65 years) while avoiding thyroid hormone treatment where possible for elderly patients with TSH <10 mIU/L) seem reasonable today. LT4 remains the mainstay of thyroid hormone replacement, titrated carefully to normalize TSH (preparations with a wide range of tablet strengths may be helpful when starting at very low LT4 doses, such as for patients with cardiac disease158). There is no evidence for the use of triiodothyronine (T3) in thyroid hormone replacement, at least for now, although appropriately designed trials may establish a role for supplementation with triiodothyronine in selected subgroups in the future (reviewed elsewhere159).
Key considerations in the pharmacological management of treatment-resistant depression
Published in Expert Opinion on Pharmacotherapy, 2021
Mani Yavi, Ioline D. Henter, Lawrence T Park, Carlos Zarate
The use of triiodothyronine (T3) as a potential augmentation strategy stems from previous studies indicating an association between thyroid hormone levels and severity of depressive symptoms as well as from studies that used T3 and levothyroxine as adjunctive treatments for depression [44]. Because of individual differences in thyroid hormone metabolism, T3 is the preferred treatment due to its faster response time [45]; however, there is concern regarding its long-term use, although it is well tolerated at low doses. A meta-analysis comparing 11 augmentation agents across 48 randomized controlled trials found significant effects for T3 augmentation [37]. Another meta-analysis of eight studies found that patients who received T3 augmentation were twice as likely to exhibit an antidepressant response than those who received standard treatment [46]. However, the STAR*D study found a remission rate of 24.7% for TRD patients who received augmented treatment with T3, which was not significantly better than other options [35]. Interestingly, results from another meta-analysis suggested that T3 augmentation might be more successful with TCAs than with SSRIs [47]. In addition, some of the reviewed studies found lower baseline thyroid function in the group that responded to T3, suggesting that antidepressant response to this agent may be due to sub-optimal thyroid function, but these findings were not consistent [47].
Ultrasound-guided thermal ablation for papillary thyroid microcarcinoma: a multicenter retrospective study
Published in International Journal of Hyperthermia, 2021
Xiao-Jing Cao, Ming-An Yu, Ya-Lin Zhu, Lu Qi, Zhi-Bin Cong, Guo-Zhen Yan, Juan Liu, Hong-Ling Wang, Geng Liu, Jian-Qin Guo, Ying Hao, Zhong-Hua Wang, Xue Wang, Jun-Feng He, Aini Shataer, Xiao-Fang Liu, Zhen-Long Zhao, Ying Wei, Li-Li Peng, Yan Li, Shu-Rong Wang, Ying Che
High-resolution US examination of the neck was performed for each patient to evaluate the tumor size (including three meridians: the largest diameter and two other perpendicular diameters), location, and to detect LNM. Tumor volume (V) was reported in mm3 using the ellipsoid volume formula: V = 0.524abc, where a is the largest diameter, and b and c are the two perpendicular diameters. CT of the neck and lung was performed in all patients to exclude metastasis. US-guided fine needle aspiration or core needle biopsy was performed in all patients to obtain pathology specimens. Specimens were sent for cytological or histological pathology and BRAF V600E mutation tests. Blood examinations, including measurements of thyroid function (serum triiodothyronine, serum free thyroxine, and serum thyrotropin), platelet count, and blood coagulation tests were performed.