title: Oxiradical-dependent photoemission induced by a phacoemulsification probe.
abstract: Oxygen free radical formation by conventional phacoemulsification devices has been postulated as a possible mechanism of corneal endothelial damage during surgery. To test this hypothesis, phacoemulsification probe-induced free radical production was visualized using a single photon-counting camera and an O(2-)-sensitive luciferin derivative, 2-methyl-6-[p-methoxyphenyl-3,7-dihydroimidazo [1,2-a]pyrazin-3-one (MCLA), which allows the visualization of spatial and temporal alterations in free radical production. Within 1 min after starting ultrasound emission, MCLA-dependent chemiluminescence was increased significantly, the intensity of which was maximal at the tip of the probe and tapered along a gradient toward distal portions. The chemiluminescence was suppressed significantly by adding either superoxide dismutase (300 U/ml) or sodium azide (20 mmol/l). By adding deuterium to the medium, MCLA-dependent chemiluminescence significantly increased, suggesting the involvement of singlet oxygen in the reaction.
authors.affiliation: Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Shimmura
authors.forename: K
authors.initials: K
authors.lastname: Tsubota
authors.forename: Y
authors.initials: Y
authors.lastname: Oguchi
authors.forename: D
authors.initials: D
authors.lastname: Fukumura
authors.forename: M
authors.initials: M
authors.lastname: Suematsu
authors.forename: M
authors.initials: M
authors.lastname: Tsuchiya
mesh_terms: D001386:Azides / Q000737:chemistry; D002387:Cataract Extraction / Q000295:instrumentation*; D003574:Cytochrome c Group / Q000378:metabolism; D005609:Free Radicals / Q000378:metabolism; D007093:Imidazoles; D008163:Luminescent Measurements; D011719:Pyrazines; D011827:Radiation; D019810:Sodium Azide; D013482:Superoxide Dismutase / Q000737:chemistry; D013481:Superoxides / Q000378:metabolism*; D014463:Ultrasonography / Q000295:instrumentation
chemical_list: D001386:Azides; D003574:Cytochrome c Group; D005609:Free Radicals; D007093:Imidazoles; D011719:Pyrazines; D013481:Superoxides; C063412:2-methyl-6-(4-methoxyphenyl)-3,7-dihydroimidazo(1,2-alpha)pyrazin-3-one; D019810:Sodium Azide; D013482:Superoxide Dismutase