| schatzki ring | <radiology> B ring of distal oesophagus, squamo-columnar junction, with or without hiatus hernia, intemittent symptoms if 13-20 mm, steakhouse syndrome, Treatment: balloon or bougie see: oesophageal webs and rings (12 Dec 1998) |
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| schatzki's ring | A congenital anatomic narrowing in the lower 1/3 of the oesophagus that is the result of inappropriate embryological development of the oesophagus. Symptoms include difficulty swallowing and chest pain (under the sternum). Treatment involves the use of a fibreoptic endoscope using a dilator to open up the narrowed segment of the oesophagus. (27 Sep 1997) |
| heterocyclic compounds, 1-ring | A class of organic compounds containing a ring structure made up of more than one kind of atom, usually carbon plus another atom. The ring structure can be aromatic or nonaromatic. (12 Dec 1998) |
| heterocyclic compounds, 2-ring | A class of organic compounds containing two ring structures, one of which is made up of more than one kind of atom, usually carbon plus another atom. The heterocycle may be either aromatic or nonaromatic. (12 Dec 1998) |
| heterocyclic compounds, 3-ring | A class of organic compounds containing three ring structures, one of which is made up of more than one kind of atom, usually carbon plus another atom. The heterocycle may be either aromatic or nonaromatic (12 Dec 1998) |
| heterocyclic compounds, bridged-ring | A class of organic compounds which contain two rings that share a pair of bridgehead carbon atoms. (12 Dec 1998) |
| Schwalbe's ring | The periphery of the cornea marking the termination of Descemet's membrane and the anterior border of the trabecular meshwork; an important landmark in gonioscopy. Synonym: Schwalbe's ring. (05 Mar 2000) |
| scleral ring | The appearance of the sclera adjacent to the optic disk when the retinal pigment epithelium does not extend to the optic nerve. (05 Mar 2000) |
| purine imidazole-ring cyclase | <enzyme> Recyclises ring-opened purine formamidopyrimidines in irradiated DNA, restoring the c-8 to n-9 band, does not require ATP Registry number: EC 6.3.3.- Synonym: purir cyclase (26 Jun 1999) |
| pyranose ring | <chemistry> A six-membered cyclic haemiacetal or ketal. (09 Jan 1998) |
| pyrrole ring | <biochemistry, chemistry> A heterocyclic ring structure, found in many important biological pigments and structures that involve an activated metal ion, for example chlorphyll, hem. (18 Nov 1997) |
| S ring | <molecular biology> The static part of the bacterial motor: a ring of 15 or 17 sub units (one or less more than the M ring), anchored to the inner surface of the cell wall. (10 Mar 1998) |
| neonatal ring | In deciduous teeth, a line of demarcation between prenatal and postnatal enamel. Synonym: neonatal ring. (05 Mar 2000) |
| subcutaneous ring | The slit-like opening in the aponeurosis of the external oblique muscle of the abdominal wall through which the spermatic cord (round ligament in the female) and inguinal hernias emerge from the inguinal canal. See: aponeurosis of external abdominal oblique muscle. Synonym: annulus inguinalis superficialis, external inguinal ring, subcutaneous ring. (05 Mar 2000) |
| superficial inguinal ring | The slit-like opening in the aponeurosis of the external oblique muscle of the abdominal wall through which the spermatic cord (round ligament in the female) and inguinal hernias emerge from the inguinal canal. See: aponeurosis of external abdominal oblique muscle. Synonym: annulus inguinalis superficialis, external inguinal ring, subcutaneous ring. (05 Mar 2000) |