AV nicking

AV nicking

AV, or atreovenous nicking is the phenomenon where, on ophthalmologic examination, an arteriole is seen crossing a venule resulting in impaction of the vein with bulging on either side of the crossing. This is most commonly seen in hypertensive retinopathy.

It is thought that, since the arteriole and venule share a sheath, the arteriole's thicker walls push against those of the venule forcing the venule to collapse. This makes the venule form an hourglass shape around the arteriole. Other theories suggest that this results not from compression from the arteriole but from sclerotic thickening or glial cell proliferation at the site where the two vessels cross. [ [http://www.emedicine.com/oph/topic488.htm eMedicine - Hypertension : Article by Bradley M Hughes ] ]

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  • Nicking — Nick ing, n. [From {Nick}, v. t.] (Coal Mining) (a) The cutting made by the hewer at the side of the face. (b) pl. Small coal produced in making the nicking. [1913 Webster] …   The Collaborative International Dictionary of English

  • Nicking enzyme amplification reaction — (NEAR) is a method for in vitro DNA amplification like the polymerase chain reaction (PCR). NEAR is isothermal, replicating DNA at a constant temperature using a polymerase (and nicking enzyme) to exponentially amplify the DNA at a temperature… …   Wikipedia

  • Nicking enzyme — A nicking enzyme (or nicking endonuclease) is an enzyme that cuts one strand of a double stranded DNA at a specific recognition nucleotide sequences known as a restriction site. Such enzymes hydrolyse, cut, only one strand of the DNA duplex, to… …   Wikipedia

  • Nicking — Nick Nick, v. t. [imp. & p. p. {Nicked} (n[i^]kt); p. pr. & vb. n. {Nicking}.] 1. To make a nick or nicks in; to notch; to keep count of or upon by nicks; as, to nick a stick, tally, etc. [1913 Webster] 2. To mar; to deface; to make ragged, as by …   The Collaborative International Dictionary of English

  • nicking — Localized constrictions in retinal blood vessel s. arteriovenous n. constriction of a retinal vein at an artery vein crossing. * * * nick·ing nik iŋ n localized constriction of a retinal vein by the pressure from an artery crossing it seen esp.… …   Medical dictionary

  • nicking — nɪk n. small cut; chip; notch; jail (British Slang); pinch, steal (British) v. cut slightly; chip; make a notch in; steal, pinch (British Slang); demand price; arrest (British Slang) …   English contemporary dictionary

  • nicking — nick·ing …   English syllables

  • NICKING — …   Useful english dictionary

  • Nick — Nick, v. t. [imp. & p. p. {Nicked} (n[i^]kt); p. pr. & vb. n. {Nicking}.] 1. To make a nick or nicks in; to notch; to keep count of or upon by nicks; as, to nick a stick, tally, etc. [1913 Webster] 2. To mar; to deface; to make ragged, as by… …   The Collaborative International Dictionary of English

  • Nicked — Nick Nick, v. t. [imp. & p. p. {Nicked} (n[i^]kt); p. pr. & vb. n. {Nicking}.] 1. To make a nick or nicks in; to notch; to keep count of or upon by nicks; as, to nick a stick, tally, etc. [1913 Webster] 2. To mar; to deface; to make ragged, as by …   The Collaborative International Dictionary of English

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