Noninvasive Metabolic Analysis of Preserved Rabbit Cornea

Tsubota, Kazuo; Laing, Ronald A.; Chiba, Keizo; Hanninen, Laila A.; Kenyon, Kenneth R.

doi:10.1001/archopht.1988.01060140885034

Cited by 11 publications

(12 citation statements)

References 7 publications

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“…The instrumentation of fluorometry has been described previously [3][4][5][6][7][8]. Briefly, a photon-counting spectrofluorometer coupled to a modified eye bank specular microscope (Bio-Optics, Model LSM 2100CM.…”

Section: Ocular Redox Fluorometrysupporting

confidence: 48%

“…The ocular redox fluorometry used in the present study is based on the property that PN fluoresce only in the reduced form and Fp only in the oxidized form [3][4][5][6][7][8]. The mea sured relative fluorescence intensity depends upon factors such as availability and utiliza tion of oxygen, availability of metabolic sub strates, and tissue metabolic work load deter- mined by mitochondrial respiration rate [7], Therefore, the changes of ocular redox fluor ometry signals reflect the metabolic changes of the tissue induced by various conditions such as contact lens wear, tissue preservation, and application of metabolic inhibitors [3][4][5][6][7][8].…”

Section: Discussionmentioning

confidence: 44%

“…The mea sured relative fluorescence intensity depends upon factors such as availability and utiliza tion of oxygen, availability of metabolic sub strates, and tissue metabolic work load deter- mined by mitochondrial respiration rate [7], Therefore, the changes of ocular redox fluor ometry signals reflect the metabolic changes of the tissue induced by various conditions such as contact lens wear, tissue preservation, and application of metabolic inhibitors [3][4][5][6][7][8]. The presence of a relatively high level of PN measured using chemical analysis in the cor neal epithelium have been reported [2,[10][11][12].…”

Section: Discussionmentioning

confidence: 48%

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Distribution of Autofluorescence in the Rabbit Corneal Epithelium

et al. 1993

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Autofluorescence from reduced pyridine nucleotides (PN) and oxidized flavoproteins (Fp) was measured in order to detect the difference in redox states in rabbit corneal epithelium. The enucleated rabbit eye was mounted in an eye bank eye container with McCarey-Kaufman medium, and the autofluorescence was measured using ocular redox fluorometry as a function of depth. The PN signal distributed evenly whereas the Fp signal was greater in the posterior epithelial region than in the anterior region (p < 0.05). The PN/Fp ratio, a sensitive indicator of tissue redox state, was less in the posterior region. After the application of 1 mM of potassium cyanide in the medium, the ratio increased significantly in each layer (p < 0.001), and the difference between anterior and posterior region diminished. These results indicate that ocular redox fluorometry has the potential to resolve the redox states ofthe various layers of the corneal epithelium. The posterior region of the epithelium is more active in mitochondrial respiration than the anterior region.

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Section: Ocular Redox Fluorometrysupporting

confidence: 48%

Section: Discussionmentioning

confidence: 44%

Section: Discussionmentioning

confidence: 48%

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Distribution of Autofluorescence in the Rabbit Corneal Epithelium

et al. 1993

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“…Corneal redox fluorometry provides an objective method to evaluate the preserved cornea [9], Another nonivasive method is phosphorous nuclear magnetic resonance [ 10].…”

Section: Discussionmentioning

confidence: 44%

Endothelial Cells of Rabbit Cornea in Different Storage Conditions

Scharf

Nahir²

1991

Ophthalmic Res

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The metabolic functions of endothelial cells of the rabbit cornea in different storage conditions were studied using quantitative cytochemistry. The corneas were stored for 2 h, and 1, 3, 7, 14 and 21 days in dexol at 4°C and in culture medium at 37°C. It was shown that glycolysis as expressed by the activity of the cytosolic enzymes glyceraldehyde 3-phosphate dehydrogenase, glucose-6-phosphate dehydrogenase and lactic dehydrogenase is well preserved for 1 week in dexol and for 3 days only in the culture medium. Mitochondrial enzymes as shown by succinate dehydrogenase and fatty acid oxidation activity show a similar pattern. Uridine diphosphoglucose dehydrogenase, which plays an important part in proteoglycan synthesis, is markedly decreased in both media, but retains its activity in dexol for a slightly longer time. Keratan and chondroitin sulfate content show a sharp drop in the culture medium at 37°C as compared to dexol. This study demonstrates the superiority of dexol at 4°C over the culture medium at 37°C. Quantitative cytochemistry is a useful tool for studying the metabolism of endothelial cells.

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“…These signals have been demonstrated to be valuable for the detection of metabolic changes in cornea and lens under a variety of conditions.3-8 The PN/Fp ratio has been shown to be an especially sensitive indicator of tissue metabolic changes, since the ratio is less susceptible to tissue movements during the measurement than is each signal separately.9 The ratio was also shown to change in preserved rabbit corneal endothelium as a function of storage time. 5 We thus expect the method to be valuable for donor cornea selection.…”

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confidence: 99%

Non-invasive assessment of the donor corneal endothelium using ocular redox fluorometry.

Shimazaki

Laing

Tsubota

et al. 1996

British Journal of Ophthalmology

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Conclusion-Ocular redox fluorometry is useful for assessing donor corneal endothelial viability. Combination of ocular redox fluorometry and specular microscopy may increase the ability of donor cornea selection. (BrJ Ophthalmol 1996; 80: 69-73) Proper evaluation of donor corneas is the key to success in corneal transplantation. To date, slitlamp examination is the objective method being routinely used in eye banks, and now specular microscopy has been introduced in many eye banks. Although it has been shown that morphometric alterations of corneal endothelium correlate with donor cornea viability,' a more sensitive and accurate measurement technique than specular microscopy is necessary for reliable assessment of the corneal condition.Nuclear magnetic resonance (NMR) is a noninvasive method for the measurement of metabolism, and it has been shown to be capable of assessing metabolic changes in donor corneas.2However, at present resolutions the method cannot distinguish metabolic changes in endothelium from those in other layers. In addition, the complexity and high cost prevent the method from being introduced in most eye banks.Ocular redox fluorometry is an alternative non-invasive method for measuring tissue metabolic changes.3-8 It measures autofluorescence from reduced pyridine nucleotides (PN) and oxidised flavoproteins (Fp). These signals have been demonstrated to be valuable for the detection of metabolic changes in cornea and lens under a variety of conditions.3-8 The PN/Fp ratio has been shown to be an especially sensitive indicator of tissue metabolic changes, since the ratio is less susceptible to tissue movements during the measurement than is each signal separately.9 The ratio was also shown to change in preserved rabbit corneal endothelium as a function of storage time.5 We thus expect the method to be valuable for donor cornea selection.In the present study, we investigated whether or not the method was valuable for detecting metabolic changes in the human corneal endothelium in eye banks. Corneas from recipients of corneal transplantation were used. Association between ocular redox fluorometry or specular microscopy and histopathology was studied. Materials and methods PATIENT PROFILEForty two corneas from recipients of penetrating keratoplasty were obtained at the time of surgery. Mean age of the recipients was 66 1 (SD 17.4) years, with the male to female ratio of 1:1. The leading cause of keratoplasty was bullous keratopathy (n=23), followed by Fuchs' dystrophy (n=8), keratoconus (n=4), and regraft (n=4). After the corneal buttons were removed, they were stored in the refrigerator overnight with McCarey-Kaufman (MK) medium, and examinations were performed thereafter.Four corneas from four donors, which were rejected for keratoplasty because they failed to pass virus serology, were also studied. Three of these donors were male and one was female, with the mean age of 418 years. SPECULAR MICROSCOPYCorneal endothelium of the 36 corneas (32 recipient and four donor corneas) were evaluated by...

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Noninvasive Metabolic Analysis of Preserved Rabbit Cornea

Cited by 11 publications

References 7 publications

Distribution of Autofluorescence in the Rabbit Corneal Epithelium

Distribution of Autofluorescence in the Rabbit Corneal Epithelium

Endothelial Cells of Rabbit Cornea in Different Storage Conditions

Non-invasive assessment of the donor corneal endothelium using ocular redox fluorometry.

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