| e | Greek letter epsilon; heavy chain of IgE; permittivity; specific absorptivity |
|---|---|
| Fd | the amino-terminal portion of the heavy chain of an immunoglobulin molecule; ferredoxin |
| FTH | ferritin heavy chain; fracture threshold |
| Gm | an allotype marker on the heavy chains of immunoglobins |
| HC | hair cell; hairy cell; handicapped; head circumference; head compression; health care; healthy contr... |
| heavy chain disease | A disorder of immunoglobulin synthesis in which large quantities of abnormal heavy chains are excreted in the urine. The amino acid sequences of the n- (amino-) terminal regions of these chains are normal, but they have a deletion extending from part of the variable domain through the first domain of the constant region, so that they cannot form cross-links to the light chains. The defect arises through faulty coupling of the variable (v) and constant (c) region genes. (12 Dec 1998) |
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| heavy hydrogen | <radiobiology> Somewhat informal alternative name for deuterium. See: deuterium. (10 Jan 1998) |
| heavy liquid petrolatum | <chemical> A mixture of liquid hydrocarbons obtained from petroleum. It is used as laxative, lubricant, ointment base, and emollient. Pharmacological action: cathartic, emollients, ointment bases. Chemical name: Hydrocarbon oils (12 Dec 1998) |
| heavy metal | A metal with a high specific gravity, typically larger than 5; e.g., Fe, Co, Cu, Mn, Mo, Zn, V. (05 Mar 2000) |
| heavy metal neuropathy | Peripheral nervous system disorders attributed to intoxication of one of the heavy metals: arsenic, gold, lead, mercury, platinum and thallium. (05 Mar 2000) |
| heavy nitrogen | The less common stable nitrogen isotope, making up 0.37% of natural nitrogen. Synonym: heavy nitrogen. (05 Mar 2000) |
| heavy oxygen | A stable oxygen isotope making up 0.20% of natural oxygen; used in mass spectrometry and in NMR studies of tissue. Synonym: heavy oxygen. (05 Mar 2000) |
| heavy spar | <chemical> Native barium sulphate or barite, so called because of its high specific gravity as compared with other non-metallic minerals. Source: Websters Dictionary (01 Mar 1998) |
| heavy water | most commonly used by cell biologists to stabilise microtubules. (18 Nov 1997) |
| immunoglobulins, heavy-chain | Major components of immunoglobulin molecules. They are the larger of the two types of polypeptide chains responsible for the biological and immunological properties of the different immunoglobulins. They differ according to the class of ig from which they were isolated, contain 450 to 600 amino acid residues per chain, and have molecular weights of 51-72 kD. One ig molecule comprises two heavy and two light chains. (12 Dec 1998) |
| Alfven ion cyclotron instability | <radiobiology> An electromagnetic microinstability near the ion cyclotron frequency, driven by the ion loss cone in a mirror device. Acronym: AIC (13 Nov 1997) |
| aquo-ion | A hydrated ion; an ion containing one or more water molecules; e.g., Cu(H2O)42+. (05 Mar 2000) |
| gated ion channel | <physiology> Transmembrane proteins of excitable cells, that allow a flux of ions to pass only under defined circumstances. Channels may be either voltage gated, such as the sodium channel of neurons or ligand gated such as the acetylcholine receptor of cholinergic synapses. Channels tend to be relatively ion specific and allow fluxes of typically 1000 ions to pass in around 1ms, they are thus much faster at moving ions across a membrane than transport ATPases. (05 May 1997) |
| central metal ion | <chemistry> The metal ion to which the ligands are attached at the centre of a coordination complex. (09 Oct 1997) |
| voltage gated ion channel | <physiology> A transmembrane ion channel whose permeability to ions is extremely sensitive to the transmembrane potential difference. These channels are essential for neuronal signal transmission and for intracellular signal transduction. See: sodium channel. (18 Nov 1997) |