| amplification | <molecular biology> An increase in the number of copies of a specific DNA fragment, can be in vivo or in vitro. See: cloning, polymerase chain reaction. (09 Oct 1997) |
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| random amplification of polymorphic DNA | <molecular biology> A term originally invented by polymer chemists to describe a disordered tangle of a linear polymer chain with curved sections. In DNA parlance the random coil refers to the structure that results from melting or other forms of separation of the double helix, i.e. Helix coil transition. (18 Nov 1997) |
| gene amplification | <molecular biology> Selective replication of DNA sequence within a cell, producing multiple extra copies of that sequence. The best known example occurs during the maturation of the oocyte of Xenopus, where the set (normally 500 copies) of ribosomal RNA genes is replicated some 4,000 times to give about 2 million copies. (18 Nov 1997) |
| genetic amplification | A process for producing an increase in pertinent genetic material, particularly for increasing the proportion of plasmid DNA to that of bacterial DNA. Includes the production of extrachromosomal copies of the genes for RNA. (05 Mar 2000) |
| DNA amplification | <molecular biology> The use of enzymes in making millions or billions of copies of a single DNA sequence (see PCR). (14 Nov 1997) |
| ligase amplification reaction | <molecular biology> Method for detecting small quantities of a target DNA, with utility similar to PCR. It relies on DNA ligase to join adjacent synthetic oligonucleotides after they have bound the target DNA. Their small size means that they are destabilised by single base mismatches and so form a sensitive test for the presence of mutations in the target sequence. (18 Nov 1997) |
| afferent loop syndrome | <syndrome> A complication of gastrojejunostomy, caused by acute or chronic obstruction of the afferent loop due to hernia, intussusception, kinking, volvulus, etc. It is characterised by pain and vomiting of bile-stained fluid and includes acute afferent loop obstruction and bilious vomiting. (12 Dec 1998) |
| arch-loop-whorl system | See: Galton's system of classification of fingerprints. (05 Mar 2000) |
| Biebl loop | A continuous loop of small intestine brought through the abdominal wall to a subcutaneous location, for observation of motility. (05 Mar 2000) |
| blind loop syndrome | <syndrome> Malabsorption, especially of vitamin b12 or folic acid, due to metabolic competition by bacteria proliferating in a segment of small intestine excluded from normal peristaltic movement; it may occur as a postoperative complication of side-to-side anastomosis of intestine, as a result of intestinal diverticula, fistula, etc. (12 Dec 1998) |
| bulboventricular loop | The portion of the early-somite embryonic cardiac tube that evolves into the ventricle and bulbus cordis. Synonym: ventricular loop. (05 Mar 2000) |
| gamma loop | The reflex arc consisting of small anterior horn cells and neuroma, their small fibres projecting to the intrafusal bundle producing its contraction, which initiates the afferent impulses that pass through the posterior root to the anterior horn cells, inducing a stretch reflex. Synonym: gamma motor neurons, gamma motor system, Granit's loop. (05 Mar 2000) |
| vector loop | <physiology> An irregular, usually elliptical, curve representing the average direction and magnitude of the heart's action from moment to moment throughout the cardiac cycle. See: vector, vectorcardiogram. (06 Mar 2000) |
| gastrojejunal loop obstruction syndrome | <syndrome> A complication of gastrojejunostomy, caused by acute or chronic obstruction of the afferent loop due to hernia, intussusception, kinking, volvulus, etc. It is characterised by pain and vomiting of bile-stained fluid and includes acute afferent loop obstruction and bilious vomiting. (12 Dec 1998) |
| ventricular loop | The portion of the early-somite embryonic cardiac tube that evolves into the ventricle and bulbus cordis. Synonym: ventricular loop. (05 Mar 2000) |