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Propylthiouracil
Propylthiouracil (PTU) is a medication used to treat hyperthyroidism. This includes hyperthyroidism due to Graves' disease and toxic multinodular goiter. In a thyrotoxic crisis it is generally more effective than methimazole. Otherwise it is typically only used when methimazole, surgery, and radioactive iodine is not possible. It is taken by mouth. Common side effects include itchiness, hair loss, parotid swelling, vomiting, muscle pains, numbness, and headache. Other severe side effects include liver problems and low blood cell counts. Use during pregnancy may harm the baby. Propylthiouracil is in the antithyroid family of medications. It works by decreasing the amount of thyroid hormone produced by the thyroid gland and blocking the conversion of thyroxine (T4) to triiodothyronine (T3). Propylthiouracil came into medical use in the 1940s. It is on the World Health Organization's List of Essential Medicines. Side effects Propylthiouracil is generally well tolerat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antithyroid
An antithyroid agent is a hormone antagonist acting upon thyroid hormones. The main antithyroid drugs are carbimazole (in the UK), methimazole (in the US), and propylthiouracil (PTU). A less common antithyroid agent is potassium perchlorate. Graves' disease In Graves' disease, treatment with antithyroid medications must be given for six months to two years, in order to be effective. Even then, upon cessation of the drugs, the hyperthyroid state may recur. Side effects of the antithyroid medications include a potentially fatal reduction in the level of white blood cells. A randomized control trial testing single dose treatment for Graves' found methimazole achieved euthyroid state more effectively after 12 weeks than did propylthiouracil (77.1% on methimazole 15 mg vs 19.4% in the propylthiouracil 150 mg groups). But generally both drugs are considered equivalent. A study has shown no difference in outcome for adding thyroxine to antithyroid medication and continuing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graves' Disease
Graves' disease (german: Morbus Basedow), also known as toxic diffuse goiter, is an autoimmune disease that affects the thyroid. It frequently results in and is the most common cause of hyperthyroidism. It also often results in an enlarged thyroid. Signs and symptoms of hyperthyroidism may include irritability, muscle weakness, sleeping problems, a fast heartbeat, poor tolerance of heat, diarrhea and unintentional weight loss. Other symptoms may include thickening of the skin on the shins, known as pretibial myxedema, and eye bulging, a condition caused by Graves' ophthalmopathy. About 25 to 30% of people with the condition develop eye problems. The exact cause of the disease is unclear; however, it is believed to involve a combination of genetic and environmental factors. A person is more likely to be affected if they have a family member with the disease. If one twin is affected, a 30% chance exists that the other twin will also have the disease. The onset of disease may b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thyroid Gland
The thyroid, or thyroid gland, is an endocrine gland in vertebrates. In humans it is in the neck and consists of two connected lobes. The lower two thirds of the lobes are connected by a thin band of tissue called the thyroid isthmus. The thyroid is located at the front of the neck, below the Adam's apple. Microscopically, the functional unit of the thyroid gland is the spherical thyroid follicle, lined with follicular cells (thyrocytes), and occasional parafollicular cells that surround a lumen containing colloid. The thyroid gland secretes three hormones: the two thyroid hormones triiodothyronine (T3) and thyroxine (T4)and a peptide hormone, calcitonin. The thyroid hormones influence the metabolic rate and protein synthesis, and in children, growth and development. Calcitonin plays a role in calcium homeostasis. Secretion of the two thyroid hormones is regulated by thyroid-stimulating hormone (TSH), which is secreted from the anterior pituitary gland. TSH is regulated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thyroid Hormone
File:Thyroid_system.svg, upright=1.5, The thyroid system of the thyroid hormones T3 and T4 rect 376 268 820 433 Thyroid-stimulating hormone rect 411 200 849 266 Thyrotropin-releasing hormone rect 297 168 502 200 Hypothalamus rect 66 216 386 256 Anterior pituitary gland rect 66 332 342 374 Negative feedback rect 308 436 510 475 Thyroid gland rect 256 539 563 635 Thyroid hormones rect 357 827 569 856 Catecholamine rect 399 716 591 750 Metabolism desc bottom-left Thyroid hormones are any hormones produced and released by the thyroid gland, namely triiodothyronine (T3) and thyroxine (T4). They are tyrosine-based hormones that are primarily responsible for regulation of metabolism. T3 and T4 are partially composed of iodine. A deficiency of iodine leads to decreased production of T3 and T4, enlarges the thyroid tissue and will cause the disease known as simple goitre. The major form of thyroid hormone in the blood is thyroxine (T4), whose half-life of around one week is longer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toxic Multinodular Goiter
Toxic multinodular goiter (TMNG), also known as multinodular toxic goiter (MNTG), is an active multinodular goiter associated with hyperthyroidism. It is a common cause of hyperthyroidism in which there is excess production of thyroid hormones from functionally autonomous thyroid nodules, which do not require stimulation from thyroid stimulating hormone (TSH). Toxic multinodular goiter is the second most common cause of hyperthyroidism (after Graves' disease) in the developed world, whereas iodine deficiency is the most common cause of hypothyroidism in developing-world countries where the population is iodine-deficient. (Decreased iodine leads to decreased thyroid hormone.) However, iodine deficiency can cause goiter (thyroid enlargement); within a goitre, nodules can develop. Risk factors for toxic multinodular goiter include individuals over 60 years of age and being female. Signs and symptoms Symptoms of toxic multinodular goitre are similar to that of hyperthyroidism, inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methimazole
Thiamazole, also known as methimazole, is a medication used to treat hyperthyroidism. This includes Graves disease, toxic multinodular goiter, and thyrotoxic crisis. It is taken by mouth. Full effects may take a few weeks to occur. Common side effects include itchiness, hair loss, nausea, muscle pain, swelling, and abdominal pain. Severe side effects may include low blood cell counts, liver failure, and vasculitis. Use is not recommended during the first trimester of pregnancy due to the risk of congenital anomalies, but it may be used in the second trimester or third trimester. It may be used during breastfeeding. Those who developed significant side effects may also have problems with propylthiouracil. Thiamazole is a thioamide and works by decreasing the production of thyroid hormones. Thiamazole was approved for medical use in the United States in 1950. It is on the World Health Organization's List of Essential Medicines. It is available as a generic medication. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperthyroidism
Hyperthyroidism is the condition that occurs due to excessive production of thyroid hormones by the thyroid gland. Thyrotoxicosis is the condition that occurs due to excessive thyroid hormone of any cause and therefore includes hyperthyroidism. Some, however, use the terms interchangeably. Signs and symptoms vary between people and may include irritability, muscle weakness, sleeping problems, a fast heartbeat, heat intolerance, diarrhea, enlargement of the thyroid, hand tremor, and weight loss. Symptoms are typically less severe in the elderly and during pregnancy. An uncommon complication is thyroid storm in which an event such as an infection results in worsening symptoms such as confusion and a high temperature and often results in death. The opposite is hypothyroidism, when the thyroid gland does not make enough thyroid hormone. Graves' disease is the cause of about 50% to 80% of the cases of hyperthyroidism in the United States. Other causes include multinodu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agranulocytosis
Agranulocytosis, also known as agranulosis or granulopenia, is an acute condition involving a severe and dangerous lowered white blood cell count (leukopenia, most commonly of neutrophils) and thus causing a neutropenia in the circulating blood. It is a severe lack of one major class of infection-fighting white blood cells. People with this condition are at very high risk of serious infections due to their suppressed immune system. In agranulocytosis, the concentration of granulocytes (a major class of white blood cells that includes neutrophils, basophils, and eosinophils) drops below 200 cells/mm3 of blood. Signs and symptoms Agranulocytosis may be asymptomatic, or may clinically present with sudden fever, rigors and sore throat. Infection of any organ may be rapidly progressive (e.g., pneumonia, urinary tract infection). Sepsis may also progress rapidly. Causes A large number of drugs have been associated with agranulocytosis, including antiepileptics (such as carbamazep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thyroperoxidase
Thyroid peroxidase, also called thyroperoxidase (TPO) or iodide peroxidase, is an enzyme expressed mainly in the thyroid where it is secreted into colloid. Thyroid peroxidase oxidizes iodide ions to form iodine atoms for addition onto tyrosine residues on thyroglobulin for the production of thyroxine (T4) or triiodothyronine (T3), the thyroid hormones. In humans, thyroperoxidase is encoded by the ''TPO'' gene. Catalyzed reaction + I− + H+ + H2O2 ⇒ + 2 H2O Iodide is oxidized to iodine radical which immediately reacts with tyrosine. + I− + H+ + H2O2 ⇒ + 2 H2O The second iodine atom is added in similar manner to the reaction intermediate 3-iodotyrosine. Function Inorganic iodine enters the body primarily as iodide, I−. After entering the thyroid follicle (or thyroid follicular cell) via a Na+/I− symporter (NIS) on the basolateral side, iodide is shuttled across the apical membrane into the colloid via pendrin, after which thyroid peroxidase oxidiz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thyroxine
File:Thyroid_system.svg, upright=1.5, The thyroid system of the thyroid hormones T3 and T4 rect 376 268 820 433 Thyroid-stimulating hormone rect 411 200 849 266 Thyrotropin-releasing hormone rect 297 168 502 200 Hypothalamus rect 66 216 386 256 Anterior pituitary gland rect 66 332 342 374 Negative feedback rect 308 436 510 475 Thyroid gland rect 256 539 563 635 Thyroid hormones rect 357 827 569 856 Catecholamine rect 399 716 591 750 Metabolism desc bottom-left Thyroid hormones are any hormones produced and released by the thyroid gland, namely triiodothyronine (T3) and thyroxine (T4). They are tyrosine-based hormones that are primarily responsible for regulation of metabolism. T3 and T4 are partially composed of iodine. A deficiency of iodine leads to decreased production of T3 and T4, enlarges the thyroid tissue and will cause the disease known as simple goitre. The major form of thyroid hormone in the blood is thyroxine (T4), whose half-life of around one week is longer th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perchlorate
A perchlorate is a chemical compound containing the perchlorate ion, . The majority of perchlorates are commercially produced salts. They are mainly used as oxidizers for pyrotechnic devices and to control static electricity in food packaging. Perchlorate contamination in food, water, and other parts of the environment has been studied in the U.S. because of harmful effects on human health. Perchlorate ions are somewhat toxic to the thyroid gland. Most perchlorates are colorless solids that are soluble in water. Four perchlorates are of primary commercial interest: ammonium perchlorate , perchloric acid , potassium perchlorate and sodium perchlorate . Perchlorate is the anion resulting from the dissociation of perchloric acid and its salts upon their dissolution in water. Many perchlorate salts are soluble in non-aqueous solutions. Production Perchlorate salts are produced industrially by the oxidation of aqueous solutions of sodium chlorate by electrolysis. This method is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thyroglobulin
Thyroglobulin (Tg) is a 660 kDa, dimeric glycoprotein produced by the follicular cells of the thyroid and used entirely within the thyroid gland. Tg is secreted and accumulated at hundreds of grams per litre in the extracellular compartment of the thyroid follicles, accounting for approximately half of the protein content of the thyroid gland. Human TG (hTG) is a homodimer of subunits each containing 2768 amino acids as synthesized (a short signal peptide of 19 aminoacids may be removed from the N-terminus in the mature protein). Thyroglobulin is in all vertebrates the main precursor to thyroid hormones, which are produced when thyroglobulin's tyrosine residues are combined with iodine and the protein is subsequently cleaved. Each thyroglobulin molecule contains approximately 100–120 tyrosine residues, but only a small number (20) of these are subject to iodination by thyroperoxidase in the follicular colloid. Therefore, each Tg molecule forms approximately 10 thyroid hormon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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