B A Berkowitz1. 1. Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, USA.
Abstract
PURPOSE: To test the hypothesis that breathing carbogen (95% O2-5% CO2) oxygenates the inner retina better than breathing 100% oxygen using an magnetic resonance imaging (MRI) method that noninvasively measures inner retinal oxygenation in normal adult and newborn rats. METHODS: Urethane-anesthetized adult and newborn (day 18) rats were studied. Sequential images were acquired in room air combined with either 100% oxygen or carbogen breathing. Normalized vitreous signal intensity changes were converted to oxygen tension changes (delta PO2) either on a pixel-by-pixel basis or in specific regions of interest. RESULTS: Systemic levels of hyperoxia during carbogen or 100% oxygen breathing were not significantly different (P > 0.05). In the adult rat, a significant difference (P = 0.017) was found in the preretinal vitreous delta PO2 during the breathing of either carbogen (130 +/- 9 mm Hg, mean +/- SEM; n = 5) or 100% oxygen (88 +/- 16 mm Hg; n = 5). Agreement was found between the MRI-determined delta PO2 values and literature oxygen microelectrodes data. In the newborn rat, significant differences (P < 0.05) in the preretinal vitreous delta PO2 were found during carbogen (164 +/- 23 mm Hg; n = 3) and oxygen breathing (91 +/- 8 mm Hg; n = 3). CONCLUSIONS: MRI delta PO2 mapping demonstrated for the first time that in the normal adult and newborn rat eye, carbogen breathing oxygenates the inner retina better than 100% oxygen breathing.
PURPOSE: To test the hypothesis that breathing carbogen (95% O2-5% CO2) oxygenates the inner retina better than breathing 100% oxygen using an magnetic resonance imaging (MRI) method that noninvasively measures inner retinal oxygenation in normal adult and newborn rats. METHODS:Urethane-anesthetized adult and newborn (day 18) rats were studied. Sequential images were acquired in room air combined with either 100% oxygen or carbogen breathing. Normalized vitreous signal intensity changes were converted to oxygen tension changes (delta PO2) either on a pixel-by-pixel basis or in specific regions of interest. RESULTS: Systemic levels of hyperoxia during carbogen or 100% oxygen breathing were not significantly different (P > 0.05). In the adult rat, a significant difference (P = 0.017) was found in the preretinal vitreous delta PO2 during the breathing of either carbogen (130 +/- 9 mm Hg, mean +/- SEM; n = 5) or 100% oxygen (88 +/- 16 mm Hg; n = 5). Agreement was found between the MRI-determined delta PO2 values and literature oxygen microelectrodes data. In the newborn rat, significant differences (P < 0.05) in the preretinal vitreous delta PO2 were found during carbogen (164 +/- 23 mm Hg; n = 3) and oxygen breathing (91 +/- 8 mm Hg; n = 3). CONCLUSIONS: MRI delta PO2 mapping demonstrated for the first time that in the normal adult and newborn rat eye, carbogen breathing oxygenates the inner retina better than 100% oxygen breathing.
Authors: Bruce A Berkowitz; Marius Gradianu; Stephen Schafer; Ying Jin; Andre Porchia; Raymond Iezzi; Robin Roberts Journal: Invest Ophthalmol Vis Sci Date: 2008-03-24 Impact factor: 4.799
Authors: Xiaoman Li; Mark E McClellan; Masaki Tanito; Philippe Garteiser; Rheal Towner; David Bissig; Bruce A Berkowitz; Steven J Fliesler; Michael L Woodruff; Gordon L Fain; David G Birch; M Suhaib Khan; John D Ash; Michael H Elliott Journal: J Biol Chem Date: 2012-03-26 Impact factor: 5.157
Authors: Bruce A Berkowitz; Marius Gradianu; David Bissig; Timothy S Kern; Robin Roberts Journal: Invest Ophthalmol Vis Sci Date: 2008-12-13 Impact factor: 4.799
Authors: Bruce A Berkowitz; Robin Roberts; Hongmei Luan; David Bissig; Bang V Bui; Marius Gradianu; David J Calkins; Algis J Vingrys Journal: Invest Ophthalmol Vis Sci Date: 2007-08 Impact factor: 4.799