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Calcium-sensing Receptor
The calcium-sensing receptor (CaSR) is a Class C G-protein coupled receptor which senses extracellular levels of calcium ions. It is primarily expressed in the parathyroid gland, the renal tubules of the kidney and the brain. In the parathyroid gland, it controls calcium homeostasis by regulating the release of parathyroid hormone (PTH). In the kidney it has an inhibitory effect on the reabsorption of calcium, potassium, sodium, and water depending on which segment of the tubule is being activated. Since the initial review of CaSR, there has been in-depth analysis of its role related to parathyroid disease and other roles related to tissues and organs in the body. 1993, Brown et al. isolated a clone named BoPCaR (bovine parathyroid calcium receptor) which replicated the effect when introduced to polyvalent cations. Because of this, the ability to clone full-length CaSRs from mammals were performed. Signal transduction The release of PTH is inhibited in response to elevations i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Class C GPCR
The class C G-protein-coupled receptors () are a class of G-protein coupled receptors that include the metabotropic glutamate receptors () and several additional receptors. Structurally they are composed of four elements; an N-terminal Signal peptide, signal sequence; a large hydrophilic extracellular agonist-binding region containing several conserved cysteine residues which could be involved in Disulfide#Occurrence in proteins, disulphide bonds; a shorter region containing seven transmembrane domains; and a C-terminal cytoplasmic domain of variable length. This protein family includes metabotropic glutamate receptors, the extracellular calcium-sensing receptors, the GABAA-rho receptor, gamma-amino-butyric acid (GABA) type B receptors, and the Vomeronasal receptor, vomeronasal type-2 receptors. Subfamilies Calcium-sensing receptor-related * extracellular calcium-sensing receptor-related ** Calcium-sensing receptor () ** GPRC6A () GABAB receptors * GABAB receptor, GABAB recept ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypocalcemia
Hypocalcemia is a medical condition characterized by low calcium levels in the blood serum. The normal range of blood calcium is typically between 2.1–2.6 mmol/L (8.8–10.7 mg/dL, 4.3–5.2 mEq/L) while levels less than 2.1 mmol/L are defined as hypocalcemic. Mildly low levels that develop slowly often have no symptoms. Otherwise symptoms may include numbness, muscle spasms, seizures, confusion, or cardiac arrest. The most common cause for hypocalcemia is iatrogenic hypoparathyroidism. Other causes include other forms of hypoparathyroidism, vitamin D deficiency, kidney failure, pancreatitis, calcium channel blocker overdose, rhabdomyolysis, tumor lysis syndrome, and medications such as bisphosphonates or denosumab. Diagnosis should generally be confirmed with a corrected calcium or ionized calcium level. Specific changes may be seen on an electrocardiogram (ECG). Initial treatment for severe disease is with intravenous calcium chloride and possibly mag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endochondral Ossification
Endochondral ossification is one of the two essential processes during fetal development of the mammalian skeletal system by which bone tissue is produced. Unlike intramembranous ossification, the other process by which bone tissue is produced, cartilage is present during endochondral ossification. Endochondral ossification is also an essential process during the rudimentary formation of long bones, the growth of the length of long bones, and the natural healing of bone fractures. Growth of the cartilage model The cartilage model will grow in length by continuous cell division of chondrocytes, which is accompanied by further secretion of extracellular matrix. This is called interstitial growth. The process of appositional growth occurs when the cartilage model also grows in thickness due to the addition of more extracellular matrix on the peripheral cartilage surface, which is accompanied by new chondroblasts that develop from the perichondrium. Primary center of ossificatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apatite
Apatite is a group of phosphate minerals, usually hydroxyapatite, fluorapatite and chlorapatite, with high concentrations of OH−, F− and Cl− ions, respectively, in the crystal. The formula of the admixture of the three most common endmembers is written as Ca10( PO4)6(OH,F,Cl)2, and the crystal unit cell formulae of the individual minerals are written as Ca10(PO4)6(OH)2, Ca10(PO4)6F2 and Ca10(PO4)6Cl2. The mineral was named apatite by the German geologist Abraham Gottlob Werner in 1786, although the specific mineral he had described was reclassified as fluorapatite in 1860 by the German mineralogist Karl Friedrich August Rammelsberg. Apatite is often mistaken for other minerals. This tendency is reflected in the mineral's name, which is derived from the Greek word ἀπατάω (apatáō), which means ''to deceive''. Geology Apatite is very common as an accessory mineral in igneous and metamorphic rocks, where it is the most common phosphate mineral. However, o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cancer
Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal bleeding, prolonged cough, unexplained weight loss, and a change in bowel movements. While these symptoms may indicate cancer, they can also have other causes. Over 100 types of cancers affect humans. Tobacco use is the cause of about 22% of cancer deaths. Another 10% are due to obesity, poor diet, lack of physical activity or excessive drinking of alcohol. Other factors include certain infections, exposure to ionizing radiation, and environmental pollutants. In the developing world, 15% of cancers are due to infections such as ''Helicobacter pylori'', hepatitis B, hepatitis C, human papillomavirus infection, Epstein–Barr virus and human immunodeficiency virus (HIV). These factors act, at least partly, by changing the genes of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asthma
Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, coughing, chest tightness, and shortness of breath. These may occur a few times a day or a few times per week. Depending on the person, asthma symptoms may become worse at night or with exercise. Asthma is thought to be caused by a combination of genetic and environmental factors. Environmental factors include exposure to air pollution and allergens. Other potential triggers include medications such as aspirin and beta blockers. Diagnosis is usually based on the pattern of symptoms, response to therapy over time, and spirometry lung function testing. Asthma is classified according to the frequency of symptoms, forced expiratory volume in one second (FEV1), and peak expiratory flow rate. It may also be classified as atopic or non-atop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alzheimer's Disease
Alzheimer's disease (AD) is a neurodegenerative disease that usually starts slowly and progressively worsens. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As the disease advances, symptoms can include problems with language, disorientation (including easily getting lost), mood swings, loss of motivation, self-neglect, and behavioral issues. As a person's condition declines, they often withdraw from family and society. Gradually, bodily functions are lost, ultimately leading to death. Although the speed of progression can vary, the typical life expectancy following diagnosis is three to nine years. The cause of Alzheimer's disease is poorly understood. There are many environmental and genetic risk factors associated with its development. The strongest genetic risk factor is from an allele of APOE. Other risk factors include a history of head injury, clinical depression, and high blood pre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteoporosis
Osteoporosis is a systemic skeletal disorder characterized by low bone mass, micro-architectural deterioration of bone tissue leading to bone fragility, and consequent increase in fracture risk. It is the most common reason for a broken bone among the elderly. Bones that commonly break include the vertebrae in the spine, the bones of the forearm, and the hip. Until a broken bone occurs there are typically no symptoms. Bones may weaken to such a degree that a break may occur with minor stress or spontaneously. After the broken bone heals, the person may have chronic pain and a decreased ability to carry out normal activities. Osteoporosis may be due to lower-than-normal maximum bone mass and greater-than-normal bone loss. Bone loss increases after the menopause due to lower levels of estrogen, and after ' andropause' due to lower levels of testosterone. Osteoporosis may also occur due to a number of diseases or treatments, including alcoholism, anorexia, hyperthyroidism, k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcilytic
Calcilytics are pharmaceutical drugs that act as antagonists at the calcium-sensing receptor (CaSR). This increases the secretion of parathyroid hormone (PTH), which has a temporary anabolic effect on bone tissue, producing an increase in both bone volume and bone density due to increased bone deposition and resorption. However, long term use of these causes resorption, degrading the bone to raise blood calcium. Consequently, these drugs have been researched for the treatment of osteoporosis, though with only limited success. More recent research has suggested a number of additional applications for these drugs, such as hyperresponsiveness and inflammation in allergic asthma Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, co .... Examples * NPS-2143 * ATF-936 * AXT-914 References { ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcimimetic
A calcimimetic is a pharmaceutical drug that mimics the action of calcium on tissues, by allosteric activation of the calcium-sensing receptor that is expressed in various human organ tissues. Calcimimetics are used to treat secondary hyperparathyroidism (SHPT). In the treatment of SHPT patients on dialysis calcimimetics does not appear to affect the risk of early death. It does decrease the need for a parathyroidectomy but caused more issues with low blood calcium levels and vomiting. Cinacalcet was the first calcimimetic to be approved. Cinacalcet mimics calcium at the parathyroid hormone receptor. This binding will increase the sensitivity of calcium-sensing receptors (CaSR) on the parathyroid gland. As a result of the receptor "thinking" there is sufficient calcium, parathyroid hormone (PTH) secretion will be reduced. Lower calcium levels will be seen as well. On August 25, 2015 Amgen Inc. announced that it had submitted a new drug application with the United States Food ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allosteric
In biochemistry, allosteric regulation (or allosteric control) is the regulation of an enzyme by binding an effector molecule at a site other than the enzyme's active site. The site to which the effector binds is termed the ''allosteric site'' or ''regulatory site''. Allosteric sites allow effectors to bind to the protein, often resulting in a conformational change and/or a change in protein dynamics. Effectors that enhance the protein's activity are referred to as ''allosteric activators'', whereas those that decrease the protein's activity are called ''allosteric inhibitors''. Allosteric regulations are a natural example of control loops, such as feedback from downstream products or feedforward from upstream substrates. Long-range allostery is especially important in cell signaling. Allosteric regulation is also particularly important in the cell's ability to adjust enzyme activity. The term ''allostery'' comes from the Ancient Greek ''allos'' (), "other", and ''stereos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Etelcalcetide
Etelcalcetide (formerly velcalcetide, trade name Parsabiv) is a calcimimetic drug for the treatment of secondary hyperparathyroidism in patients undergoing hemodialysis. It is administered intravenously at the end of each dialysis session. Etelcalcetide functions by binding to and activating the calcium-sensing receptor in the parathyroid gland. Parsabiv is currently owned by Amgen and Ono Pharmaceuticals in Japan. Medical uses Etelcalcetide is used for the treatment of secondary hyperparathyroidism in people with chronic kidney disease (CKD) on hemodialysis. Hyperparathyroidism is the condition of elevated parathyroid hormone (PTH) levels and is often observed in people with CKD. Pharmacodynamics Mechanism of action Etelcalcetide functions by binding to and activating the calcium-sensing receptor (CaSR) in the parathyroid gland as an allosteric activator, resulting in PTH reduction and suppression. Pharmacokinetics Etelcalcetide functions in a first order elimination, wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
