| middle group of mesenteric lymph nodes | The mesenteric lymph nodes located along the intestinal (jejunal and ileal) branches of the superior mesenteric artery. Synonym: nodi lymphatici superiores centrales, central mesenteric lymph nodes. (05 Mar 2000) |
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| phosphate group | <chemistry> A phosphate group on a larger molecule, where the phosphorus is single bonded to each of the four oxygens, and the other bond of one of the oxygens is attached to the rest of the molecule. This means that the entire group has a net negative charge of -3 (from the free second bonds on the oxygen atoms which are only bonded to the phosphorus atom). Often hydrogen atoms will be attached to the oxygens and sometimes double bonds between the phosphorus and an oxygen are present. (31 Dec 1997) |
| clinical cooperative group | A group of medical institutions cooperating to perform clinical research. (16 Dec 1997) |
| MN blood group antigens | <haematology, immunology> A pair of blood group antigens governed by genes that segregate independently of the ABO locus. The alleles are codominant and there are three types MM, NN and MN. Glycophorin has M or N activity and this is associated with oligosaccharides attached to the amino terminal portion of the molecule. M type glycophorin differs from N type in amino acid residues 1 and 5, although the antigenic determinants are associated with the carbohydrate side chains. (18 Nov 1997) |
| MNSs blood group | See Blood Groups appendix. (05 Mar 2000) |
| mnss blood-group system | A system of universal human blood group isoantigens with many associated subgroups. The m and n traits are codominant and the s and s traits are probably very closely linked alleles, including the u antigen. This system is most frequently used in paternity studies. (12 Dec 1998) |
| collective group | <zoology> An aggregate of related species of which the generic position is uncertain. According to the Code, for the sake of taxonomic convenience, may be treated as a genus. Such a collective group does not require a type species. Assignment to a collective group is a temporary, convenient, identifying label. (09 Jan 1998) |
| collective-group name | 1. A name established expressly for a collective group. 2. A name established for a nominal genus or subgenus and later used for a collective group. (09 Jan 1998) |
| wenlock group | <geology> The middle subdivision of the Upper Silurian in Great Britain; so named from the typical locality in Shropshire. Source: Websters Dictionary (01 Mar 1998) |
| compatibility group | <molecular biology> A group of plasmids (rings of DNA) which is able to coexist in the same cell with another plasmid from a different group. (05 Jan 1998) |
| platinum group | A group of six amphoteric elements: iridium, osmium, palladium, platinum, rhodium, and ruthenium. (05 Mar 2000) |
| connective tissue group | <physiology> A collective name for mucous tissue, dentin, bone, cartilage, and ordinary connective tissue, all derived from the mesenchyme. (05 Mar 2000) |
| control group | A group of subjects participating in the same experiment as another group of subjects, but which is not exposed to the variable under investigation. See: experimental group. (05 Mar 2000) |
| polar group | <chemistry> Any chemical grouping in which the distribution of electrons is uneven enabling it to take part in electrostatic interactions. (18 Nov 1997) |
| portage group | <geology> A subdivision of the Chemung period in American geology. See Chart of Geology. Origin: So called from the township of Portage in New York. Source: Websters Dictionary (01 Mar 1998) |