| hairpin loop | An area where single-stranded DNA or RNA has folded back on itself and nucleotides from the two separate segments have base paired, so that the resulting structure appears as the name describes. (09 Oct 1997) |
|---|---|
| helix loop helix | <molecular biology> A motif associated with transcription factors, allowing them to recognise and bind to specific DNA sequences. Two _ helices are separated by a loop. Examples: myoblast MyoD1, c myc, Drosophila genes daughterless, hairy, twist, scute, achaete, asense. Not the same as helix turn helix. (18 Nov 1997) |
| helix-loop-helix motifs | A group of 20-residue peptides characterised by two alpha helices separated by a non-helical segment. These recurring supersecondary structural patterns are found in many sequence-specific DNA-binding proteins. (12 Dec 1998) |
| sentinel loop sign | In gastrointestinal radiology, dilatation of a segment of large or small intestine, indicative of localised ileus from nearby inflammation. (05 Mar 2000) |
| Hyrtl's loop | A communicating loop between the right and left hypoglossal nerves, lying between the geniohyoid and genioglossus muscles or in the substance of the geniohyoid; it is found in about one in ten persons. Synonym: Hyrtl's anastomosis. (05 Mar 2000) |
| stem and loop structure | <molecular biology> The structure of tRNAs is so termed because it has four base paired stems and three loops (not base paired), one of which contains the anticodon. (18 Nov 1997) |
| nephronic loop | The U-shaped part of the nephron extending from the proximal to the distal convoluted tubules, consisting of descending and ascending limbs, located in the medulla renalis and medullary ray. Synonym: Henle's ansa, Henle's loop. (05 Mar 2000) |
| subclavian loop | A nerve cord connecting the middle cervical and stellate sympathetic ganglia, forming a loop around the subclavian artery. Synonym: subclavian loop, Vieussens' ansa, Vieussens' loop. (05 Mar 2000) |
| displacement loop | <molecular biology> A structure that can sometimes be seen on DNA which forms when a small area of the double-stranded molecule comes apart and becomes two single strands. The result is a structure shaped like the letter D. Single-stranded binding proteins are usually present to hold the strands apart for the purpose of DNA replication. (09 Oct 1997) |
| d loop | <molecular biology> A structure that can sometimes be seen on DNA which forms when a small area of the double-stranded molecule comes apart and becomes two single strands. The result is a structure shaped like the letter D. Single-stranded binding proteins are usually present to hold the strands apart for the purpose of DNA replication. (09 Oct 1997) |
| double loop hernia | The presence of two loops of intestine in a hernial sac. Synonym: double loop hernia. (05 Mar 2000) |
| Ivy loop wiring | Placement of a wire around two adjacent teeth to provide an attachment for intermaxillary elastics. (05 Mar 2000) |
| T loop of RNA | <molecular biology> The T loop of tRNA is the region of the molecule that is responsible for ribosome recognition. (16 Dec 1997) |
| Tphi CG loop | <molecular biology> The T loop of tRNA is the region of the molecule that is responsible for ribosome recognition. (16 Dec 1997) |
| lenticular loop | The pallidal efferent fibres curving around the medial border of the internal capsule. Synonym: ansa lenticularis, lenticular ansa. (05 Mar 2000) |