| blood group | <haematology> An inherited feature on the surface of the red blood cell. A series of related blood groups make up a blood group system such as the ABO system or the Rh system. Erythrocytic allotypes (or phenotypes) defined by one or more cellular antigenic structural groupings under the control of allelic genes. Blood groups, especially for man, are identified by agglutinins supported by specific human or animal antisera and by lectins extracted from certain plants. See: blood group antigen. (25 Jun 1999) |
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| blood group antigen | <haematology, immunology> The set of cell surface antigens found chiefly, but not solely, on blood cells. More than fifteen different blood group systems are recognised in humans. There may be naturally occurring antibodies without immunisation, especially in the case of the ABO system and matching blood groups is important for safe transfusion. In most cases the antigenic determinant resides in the carbohydrate chains of membrane glycoproteins or glycolipids. See: Rhesus, Duffy, Kell, Lewis and MN. (25 Jun 1999) |
| blood group incompatibility | A mismatch between donor and recipient blood. Antibodies present in the recipient's serum are directed against antigens in the donor product. Such a mismatch may result in a transfusion reaction in which, for example, donor blood is haemolyzed. (12 Dec 1998) |
| blood group substance | Blood group-specific substances A and B, solution of complexes of polysaccharides and amino acids that reduces the titre of anti-A and anti-B isoagglutinins in serum from group O persons; used to render group O blood reasonably safe for transfusion into persons of group A, B, or AB, but does not affect any incompatibility that results from various other factors, such as Rh. (05 Mar 2000) |
| bunyamwera group viruses | A large group of viruses from many parts of the world assigned to the bunyavirus genus of the family bunyaviridae. They are transmitted by mosquitoes and infect humans in some areas. This group contains the type species of the genus, bunyamwera virus. (12 Dec 1998) |
| calcium group | The metals of the alkaline earths: beryllium, magnesium, calcium, strontium, barium, and radium. (05 Mar 2000) |
| california group viruses | A group of viruses in the bunyavirus genus of the bunyaviridae family. They are found in temperate and arctic regions and each is closely associated with a single species of vector mosquito. The vertebrate hosts are usually small mammals but several virus species infect humans. (12 Dec 1998) |
| carbonyl group | A group in which an oxygen atom is double-bonded to a carbon atom: O=C. The carbon atom then has two additional bonds to attach to the rest of the molecule. Organic molecules containing a carbonyl group are a very important, major group of compounds studied in the field of organic chemistry. (09 Oct 1997) |
| carboxyl group | -COOH group. One of the oxygens is double-bonded to the carbon atom, making it a carbonyl group, and the other oxygen is single bonded to the carbon on one side, and single bonded to the hydrogen on the other. The remaining bond on the carbon atom is attached to the rest of the molecule. Organic molecules containing carboxyl groups are an important, major group of compounds studied in the field of organic chemistry. (09 Oct 1997) |
| vanadium group | Those elements resembling vanadium in chemical and metallurgical properties; included with vanadium are niobium and tantalum. (05 Mar 2000) |
| marathon group psychotherapy | A type of group psychotherapy characterised by uninterrupted sessions for periods of hours or days, with minimal interruptions for food and rest. (05 Mar 2000) |
| genus-group | <zoology> The taxonomic categories genus and subgenus. (09 Jan 1998) |
| CDE blood group | See Rh blood group, Blood Groups appendix. (05 Mar 2000) |
| p blood-group system | A blood group related to the abo, lewis and I systems. at least five different erythrocyte antigens are possible, some very rare, others almost universal. Multiple alleles are involved in this blood group. (12 Dec 1998) |
| peer group | Group composed of associates of same species, approximately the same age, and usually of similar rank or social status. (12 Dec 1998) |