| LED | light-emitting diode; lowest emitting dose; lupus erythematosus disseminatus |
|---|---|
| LEM | lateral eye movement; Leibovitz-Emory medium; leukocyte endogenous mediator; light emission microsco... |
| LHC | Langerhans cell histiocytosis; left heart catheterization; left hypochondrium; light-harvesting comp... |
| LMM | Lactobacillus maintenance medium; lentigo maligna melanoma; light meromyosin |
| LP | labile peptide; labile protein; laboratory procedure; lactic peroxidase; lamina propria; laryngophar... |
| chain isomer | <chemistry> One of two or more compounds having the same chemical composition but differing in the arrangement of the atoms (usually carbon atoms) forming the backbone of the structure of the compounds. (21 Mar 1998) |
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| chain reaction | A reaction in which a product reacts and thus continues the reaction. (09 Oct 1997) |
| chain reflex | A series of reflexs, each serving as a stimulus for the next. (05 Mar 2000) |
| phenylalanyl chain | A polypeptide component of insulin containing 30 amino acyl residues, beginning with a phenylalanyl residue (NH2-terminus); insulin is formed by the linkage of a B chain to an A chain by two disulfide bonds; the amino-acid composition of the B chain is a function of species. Synonym: phenylalanyl chain. (05 Mar 2000) |
| closed chain compound | Any compound in which the constituent atoms, or any part of them, form a ring. Used mainly in organic chemistry where: 1) numerous compound's contain rings of carbon atoms (carbocyclic compound's) or carbon atoms plus one or more atoms of other types (heterocyclic compound's), usually nitrogen, oxygen, or sulfur; 2) where the atoms in the ring are all of the same element (homocyclic or isocyclic compound); 3) where the ring is saturated or contains nonconjugated double bonds (alicyclic compound), the compound is similar in properties to the corresponding acyclic compound (e.g., cyclohexane resembles hexane); 4) where the ring contains conjugated double bonds in a closed loop in which there are 4n + 2 (where n is an integer) delocalised π electrons (Huckel's rule) (aromatic compound; e.g., benzene, pyridine), it is more stable than the corresponding saturated ring and exhibits unusual chemical properties characteristic of itself and not of other types of rings or of acyclic compound's. These aromatic compounds have the ability to sustain an induced ring current. Synonym: closed chain compound, ring compound. (05 Mar 2000) |
| cold chain | A system of protection against high environmental temperatures for heat-labile vaccines, sera and other biological preparations. (05 Mar 2000) |
| corticosteroid side-chain-isomerase | <enzyme> Converts 11-deoxycorticosterone to 20-hydroxy-3-oxypregn-4-en-21-al; also acts as an epimerase at c-20 Registry number: EC 5.3.1.21 Synonym: corticosteroid side chain isomerase, ccsci (26 Jun 1999) |
| polymerase chain reaction | <molecular biology, technique> The first practical system for in vitro amplification of DNA and as such one of the most important recent developments in molecular biology. Two synthetic oligonucleotide primers, which are complementary to two regions of the target DNA (one for each strand) to be amplified, are added to the target DNA (that need not be pure), in the presence of excess deoxynucleotides and Taq polymerase, a heat stable DNA polymerase. In a series (typically 30) of temperature cycles, the target DNA is repeatedly denatured (around 90_C), annealed to the primers (typically at 50-60_C) and a daughter strand extended from the primers (72_C). As the daughter strands themselves act as templates for subsequent cycles, DNA fragments matching both primers are amplified exponentially, rather than linearly. The original DNA need thus be neither pure nor abundant and the polymerase chain reaction has accordingly become widely used not only in research, but in clinical diagnostics and forensic science. Acronym: PCR (14 Oct 1997) |
| MyoD heavy chain kinase | <enzyme> Required for actin activation of the magnesium atpase activity of dictyostelium myosin id (myod); specific for myod Registry number: EC 2.7.1.- Synonym: 110-kD protein kinase, dictyostelium, dictyostelium 110-kD protein (26 Jun 1999) |
| myosin heavy chain | <protein> See myosin: do not confuse with heavy meromyosin which is a subfragment of the heavy chain of myosin II. (18 Nov 1997) |
| haemolytic chain | The haemolysis that occurs when complement is activated by the previously formed union of erythrocytes and specific antibody. (05 Mar 2000) |
| H chain | <protein> Heavy chain of immunoglobulin, see IgG, IgM, etc. (18 Nov 1997) |
| heavy chain | <protein> In general, the larger polypeptide in a multimeric protein. Thus the immunoglobulin heavy chain is of 50 kD, the light chain of 22 kD, whereas in myosin the heavy chain is very much larger (220 kD) than the light chains (~20 kD). (18 Nov 1997) |
| 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) |
| xenobiotic medium chain fatty acid - coenzyme A ligase | <enzyme> Partial amino acid sequence of enzyme from bovine liver mitochondria given I first source; has high sequence homology to human and rat sa protein Registry number: EC 6.2.1.- Synonym: xl-i ligase, xl-i carboxylic acid - CoA ligase (26 Jun 1999) |