| chelating agents | Organic chemicals that form two or more coordination bonds with a central metal ion. Heterocyclic rings are formed with the central metal atom as part of the ring. Some biological systems form metal chelates, e.g., the iron-binding porphyrin group of haemoglobin and the magnesium-binding chlorophyll of plants. They are used chemically to remove ions from solutions, medicinally against microorganisms, to treat metal poisoning, and in chemotherapy protocols. (12 Dec 1998) |
|---|---|
| chelation | <biochemistry, chemistry> Combination with a metal in complexes in which the metal is part of a ring. (21 May 1997) |
| chelation therapy | Therapy of heavy metal poisoning using agents which sequester the metal from organs or tissues and bind it firmly within the ring structure of a new compound which can be eliminated from the body. (12 Dec 1998) |
| chelator | A chelator is an organic chemical that bonds with and removes free metal ions from solutions. Chelating agents are sometimes used to treat people suffering from metal poisoning. (09 Oct 1997) |
| chelicera | One of the two anterior appendages of arachnids; in ticks and parasitic mites, the chelicerae are piercing and cutting structures, and constitute important feeding organs. Origin: G. Chele, claw, + keras, horn (05 Mar 2000) |
| chelidon | Synonym: cubital fossa. Origin: G. Chelidon, a swallow, because of fancied resemblance to the shape of a swallow's tail (05 Mar 2000) |
| cheloid | <dermatology> A sharply elevated, irregularly shaped, progressively enlarging scar due to the formation of excessive amounts of collagen in the corium during connective tissue repair. Origin: Gr. Kel = tumour, eidos = form (18 Nov 1997) |
| cheloid scar | An overgrowth of scar tissue that can result in cosmetic deformity. (27 Sep 1997) |
| Chelonia | An order of reptiles, embracing the turtles, tortoises, and terrapins, whose bodies are enclosed in a bony shell covered with epidermal scutes and formed dorsally by expanded ribs and ventrally by a sternal plastron. Origin: G. Chelone, a tortoise (05 Mar 2000) |
| chelonian | Resembling or relating to a turtle, tortoise, or terrapin. (05 Mar 2000) |
| chem- | See: chemo-. (05 Mar 2000) |
| chemexfoliation | Application of a cauterant to the skin for the purpose of causing a superficial destruction of the epidermis and upper layers of the dermis. After healing, the treated area has new epithelium. (12 Dec 1998) |
| chemiatry | Chemistry applied to, or used in, medicine; used especially with reference to the doctrines in the school of physicians in Flanders, in the 17th century, who held that health depends upon the proper chemical relations of the fluids of the body, and who endeavored to explain the conditions of health or disease by chemical principles. Source: Websters Dictionary (01 Mar 1998) |
| chemical | 1. <chemistry> Of or pertaining to, chemistry. 2. A substance composed of chemical elements or obtained by chemical processes. (21 May 1997) |
| chemical and pharmacologic phenomena | Chemical, pharmacologic, and metabolic action and interaction of drugs. (12 Dec 1998) |