Summation of Basic Endocrine Data
George H. Gass, Harold M. Kaplan in Handbook of Endocrinology, 2020
The synthesis starts with iodide, which the thyroid follicles actively take up. The iodide is oxidized to active iodine, which is incorporated into tyrosine. This is followed by peptide linkages, which are glycoproteins called thyroglobulin. Monoiodotyrosine (MIT) and diiodotyrosine then develop. These couple to form T and T, although very little rT. An enzyme called thyroid peroxidase catalyzes the whole sequence of reactions.
Invasive Tests
Vineet Relhan, Vijay Kumar Garg, Sneha Ghunawat, Khushbu Mahajan in Comprehensive Textbook on Vitiligo, 2020
Vitiligo may be associated with other autoimmune diseases, especially thyroid disease and diabetes mellitus. Other associated autoimmune diseases include pernicious anemia, Addison disease, and alopecia areata. Patients should be made aware of signs and symptoms that suggest the onset of hypothyroidism, diabetes, or other autoimmune diseases and if any signs or symptoms occur, appropriate tests should be performed. A CBC count with indices helps rule out anemia. To rule out thyroid dysfunction, thyrotropin testing is the most cost-effective screening test. Clinicians should also consider investigating for serum antithyroglobulin and antithyroid peroxidase antibodies, particularly, as antithyroid peroxidase antibodies are regarded as a sensitive and specific marker of autoimmune thyroid disease. Screening for diabetes can be accomplished with fasting blood glucose or glycosylated hemoglobin testing. Antinuclear antibody screening is also helpful.
Breast and Endocrine Surgery
Kaji Sritharan, Samia Ijaz, Neil Russell, Tim Allen-Mersh in 300 Essentials SBAs in Surgery, 2017
Papillary carcinoma is the most common thyroid malignancy (accounting for approximately 80%), followed in order of incidence by follicular, medullary and anaplastic thyroid cancer. An elevated serum calcitonin is highly suggestive of medullary carcinoma, since unlike other thyroid cancers, medullary carcinoma is derived from the calcitonin-producing C cells of the thyroid. Anaplastic tumours are the most aggressive of all the thyroid cancers and are rapidly growing, often presenting with symptoms of local invasion, e.g. hoarseness of voice and dysphagia; prognosis is poor. Pain is more a feature of benign thyroid disease. The correct answer is A. The patient has features of hyperthyroidism. Graves’ disease is the most common cause of thyrotoxicosis (accounting for approximately 70-80%); it is an autoimmune condition that typically presents in younger patients with a painless diffuse goitre and eye signs (e.g. chemosis, proptosis, periorbital oedema, ophthalmoplegia, corneal ulceration). Other extrathyroidal manifestations include pretibial myxoedema and thyroid acropachy. In addition, approximately 50% have a family history of autoimmune disease. In Graves’ disease, thyrotrophin receptor autoantibodies (TRAb) are produced and these bind to and activate the TSH receptor, leading to excess thyroxine secretion and thyrocyte proliferation. Antibodies for thyroid peroxidase are positive in autoimmune thyroid disease. Treatment includes β-blockers (for tachycardia), antithyroid medication (e.g. carbimazole), radioactive iodine and surgery in selected cases. Hashimoto’s thyroiditis is an autoimmune disease that results in hypothyroidism. Cancers rarely present with hyperthyroidism. The correct answer is E. The patient has a simple colloid/endemic goitre. A goitre is a diffuse or nodular enlargement of the thyroid gland. Symptoms may be due to compression, e.g. dysphagia, stridor, neck vein distension, dizziness on arm elevation (Pemberton’s sign), or to endocrine abnormalities, i.e. hypo- or hyperthyroidism. Goitres can be classified as sporadic or endemic and as toxic or non-toxic. The most common cause of endemic goitre is iodine deficiency and the presence of environmental or dietary goitrogens, e.g. vegetables of the Brassica family, such as cabbage. In England, endemic areas include the Chilterns, the Cotswolds, Derbyshire and Yorkshire, where iodide content of water and food has been historically low.
Thyroid peroxidase identified in human granulosa cells: another piece to the thyroid-ovary puzzle?
Published in Gynecological Endocrinology, 2017
Patrizia Monteleone, Pinuccia Faviana, Paolo Giovanni Artini
Thyroid hormones seemingly influence the maturation of the human oocyte. Thyroid hormone receptors have been isolated in granulosa mural and cumulus cells and the mature oocyte of the human ovarian follicle. Thyroid hormones are present in follicular fluid in concentrations similar to those in serum. Most importantly, enzymes involved in the chain that regulate the generation of thyroid hormones have been found in granulosa cells. For the first time, we have isolated thyroid peroxidase by immunocytochemistry in the granulosa cumulus cells of the human ovarian follicle, thereby supporting the hypothesis that the human ovarian follicle may be an independent thyroid-hormone producing unit.
Live-birth rate in euthyroid women with recurrent miscarriage and thyroid peroxidase antibodies
Published in Gynecological Endocrinology, 2016
Rosa Vissenberg, Eric Fliers, Joris A. M. van der Post, Madelon van Wely, Peter H. Bisschop, Mariette Goddijn
Thyroid autoimmunity with normal thyroid function is associated with recurrent miscarriage (RM), but the association with live birth is less clear. Therefore, we determined the association between thyroid peroxidase antibodies (TPO-Ab) and live-birth rate (LBR) in a retrospective cohort of euthyroid women with unexplained RM. We included 202 women of which 28 were TPO-Ab positive (13.9%) and 174 were TPO-Ab negative. TPO-Ab positive women (n = 10) without levothyroxine treatment had a lower LBR (29%) compared to TPO-Ab negative women (51%) (HR 0.23, 0.07–0.72, p = 0.012). The LBR in women with TPO-Ab receiving levothyroxine was not different compared women without TPO-Ab (60% versus 51%, p = 0.50). In conclusion, TPO-Ab are associated with a lower LBR in euthyroid women with unexplained RM and these women may benefit from treatment with levothyroxine.
Proportion of Antibodies to the A and B Immunodominant Regions of Thyroid Peroxidase in Graves and Hashimoto Disease
Published in Autoimmunity, 2004
Ewa Jastrze¸bska-Bohaterewicz, Andrzej Gardas
Autoantibodies to thyroid peroxidase (TPO) predominately recognise conformational epitopes, restricted to two immunodominant regions (IDR) -A and -B. We have estimated the proportion of IDR-A and -B autoantibodies in 75 Hashimoto and 68 Graves patients sera. There were no statically significant differences between Hashimoto and Graves patients sera in the IDR-A and -B autoantibodies level, despite great differences between individual patients sera. In 75 Hashimoto patients sera, the mean value of IDR-A was 24.26%, IDR-B—52.26%, IDR (A+B)—76.66%, and to non-A, non-B regions—23.5%. In 68 Graves disease patients, the mean value of IDR-A was 24.87, IDR-B—54.29, IDR (A+B)—79.07, non-A, non-B—20.92%, at a single autoantibodies concentration 5 IU/ml. At high autoantibodies concentration (50 IU/ml) the proportion of autoantibodies to the IDR (A+B) diminished to 58% and to the non-A, non-B TPO regions increased to 42%. The autoimmune response to TPO regions outside the IDR (A+B) epitopes is stronger then previously assumed and this response is also conformation dependent.
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