@article{harned_grimes_mcgahan_2003, title={The effect of UVB irradiation on ferritin subunit synthesis, ferritin assembly and Fe metabolism in cultured canine lens epithelial cells}, volume={77}, ISSN={["0031-8655"]}, DOI={10.1562/0031-8655(2003)077<0440:TEOUIO>2.0.CO;2}, abstractNote={Abstract Ferritin is a multimeric protein consisting of heavy and light chains assembled in different tissue-specific ratios, which can protect cells from oxidative stress by storing reactive iron (Fe). Because the lens is constantly exposed to UV irradiation, we studied its effects on ferritin synthesis and Fe metabolism in cultured lens epithelial cells with and without ascorbic acid (Asc). UVB caused a large increase in accumulation of newly synthesized ferritin chains; this increase was additive to that induced by Asc. In contrast to the Asc-induced increase in Fe storage, Fe storage in ferritin was unaltered by UVB. Although UVB increased accumulation of newly synthesized ferritin chains, total ferritin levels were unaltered. In contrast, Asc, which induced a quantitatively similar increase in accumulation of newly synthesized ferritin chains, doubled the total amount of ferritin. Because UVB did not change Fe storage in ferritin or the size of the labile Fe pool, it was hypothesized and then determined that these newly synthesized chains did not assemble into functional holoferritin. Numerous studies detail the effects of various treatments on de novo ferritin synthesis; however, this study provides a cautionary note regarding the conclusions of such studies in the absence of data indicating assembly of functional ferritin molecules.}, number={4}, journal={PHOTOCHEMISTRY AND PHOTOBIOLOGY}, author={Harned, J and Grimes, AM and McGahan, MC}, year={2003}, month={Apr}, pages={440–445} }
 @article{davidson_harned_grimes_duncan_wormstone_mcgahan_1998, title={Transferrin in after-cataract and as a survival factor for lens epithelium}, volume={66}, ISSN={["1096-0007"]}, DOI={10.1006/exer.1997.0413}, abstractNote={The Fe-transport protein, transferrin (Tf), is synthesized and secreted by whole lenses and cultured lens epithelial cells. Because of Tf's central role in cell growth and proliferation, its participation in lens cell proliferation following cataract extraction was explored using a rabbit model of after-cataract. Varying amounts of the central anterior lens capsule were removed (0, 35, or 80%) following extraction of the lens. The Tf content of and secretion by after-cataract lens capsular sacs containing regenerated lens tissue was determined ex vivo at 0, 3, 5, 7 and 9 weeks post-surgery. In all cases Tf content of and secretion by the lens sacs was higher than that of their contralateral controls (whole lenses). Tf secretion was up to 5-fold higher and metabolic labeling studies indicated secretion of newly synthesized Tf. The sacs contained up to 10 times the concentration of Tf as the control lenses. Human lens after-cataract capsular bags also secreted Tf. The function of Tf as a survival factor was tested on cultured lens epithelial cells. Cells cultured in serum-free medium had a survival rate of only 20-34% if the medium was changed each day. If the medium was never changed during this period, the survival rate was 43-52%, suggesting secretion of essential growth factors by these cells. Addition of 200 microg ml-1 Tf to the medium during each daily change increased survival to levels attained when the medium was not changed. Addition of Tf antibodies to the culture medium during each daily change decreased cell survival to 14%. Apparently Tf acts as a survival factor for lens epithelia and its synthesis is up-regulated in after-cataract lens sacs. These factors suggest that Tf may play an important role in the pathogenesis of lens epithelial cell proliferation and after-cataract formation following cataract surgery.}, number={2}, journal={EXPERIMENTAL EYE RESEARCH}, author={Davidson, MG and Harned, J and Grimes, AM and Duncan, G and Wormstone, IM and McGahan, MC}, year={1998}, month={Feb}, pages={207–215} }
 @article{goralska_harned_grimes_fleisher_mcgahan_1997, title={Mechanisms by which ascorbic acid increases ferritin levels in cultured lens epithelial cells}, volume={64}, ISSN={["1096-0007"]}, DOI={10.1006/exer.1996.0227}, abstractNote={A previous study demonstrated that ascorbic acid increased the concentration of the iron storage protein, ferritin. In cultured lens epithelial cells. The current study was designed to determine the mechanism by which ascorbic acid exerts this effect. Ascorbic acid increased both ferritin mRNA levels (by about 30%) and translation of ferritin (de novo synthesis was increased up to 15-fold) within 6 hr. Cycloheximide completely abolished the ability of ascorbic acid to increase ferritin levels, whereas actinomycin D only decreased it by about 30%. Therefore, the ascorbic-acid induced increase in ferritin concentration is due mainly to an increase in ferritin synthesis at the translational levels. This is a novel role for ascorbic acid. Addition of iron with ascorbic acid further increased de novo synthesis of ferritin, but this additive effect was only noted at a later time point (20 hr). Factors which decrease ferritin mRNA translation, such as the reducing agent dithiothreitol or the iron chelator desferrioxamine, reduced the ascorbic acid effect on de novo ferritin synthesis. The effects of ascorbic acid on ferritin mRNA levels may be mediated by its oxidation product, H2O2, since, like ascorbic acid, H2O2 increased ferritin mRNA levels by 30%. However, in contrast to the ascorbic acid-induced increase in translation of ferritin, H2O2 substantially decreased de novo ferritin synthesis. This effect of H2O2 could have physiological significance in eyes where concentrations of H2O2 in the aqueous humor are elevated. High levels of H2O2 could decrease the concentration of ferritin within the lens. Since ferritin sequesters iron and has been shown to decrease oxidative damage by limiting the availability of iron to catalyse free radical reactions, H2O2-induced reduction in ferritin concentration in the lens could have deleterious effects. The ability of ascorbic acid to increase ferritin concentration in lens epithelial cells could provide an additional protective mechanism for this antioxidant vitamin. The importance of ferritin to normal lens functioning is underscored by the recent finding that humans with a dominantly inherited abnormality in ferritin synthesis exhibit early bilateral cataracts.}, number={3}, journal={EXPERIMENTAL EYE RESEARCH}, author={Goralska, M and Harned, J and Grimes, AM and Fleisher, LN and McGahan, MC}, year={1997}, month={Mar}, pages={413–421} }
 @article{mcgahan_grimes_fleisher_1996, title={Hemoglobin exacerbates the ocular inflammatory response to endotoxin}, volume={234}, ISSN={["0721-832X"]}, DOI={10.1007/BF00185299}, number={10}, journal={GRAEFES ARCHIVE FOR CLINICAL AND EXPERIMENTAL OPHTHALMOLOGY}, author={McGahan, MC and Grimes, AM and Fleisher, LN}, year={1996}, month={Oct}, pages={643–647} }
 @article{mcgahan_grimes_nasisse_fleisher_1995, title={IRON UPTAKE BY CULTURED LENS EPITHELIAL-CELLS}, volume={233}, ISSN={["0721-832X"]}, DOI={10.1007/BF00200484}, abstractNote={{"Label"=>"BACKGROUND", "NlmCategory"=>"BACKGROUND"} Transferrin and Fe concentrations increase in the intraocular fluids in pathological conditions and the lens accumulates Fe during ocular inflammation. Tissues take up Fe from transferrin by two mechanisms, receptor-medicated endocytosis of diferric transferrin and a process occurring at the cell membrane which may be mediated by an oxido-reductase. However, Fe metabolism, transport and storage have not been previously investigated in the lens. This study was designed to characterize the uptake of Fe from transferrin by lens epithelial cells in culture. {"Label"=>"METHODS", "NlmCategory"=>"METHODS"} Primary, secondary and tertiary cultures of canine lens epithelial cells and cultures obtained from cataractous lenses were studied. Uptake of 59Fe from transferrin by these cultured cells was measured. Transferrin receptor populations were determined in receptor-binding assays. {"Label"=>"RESULTS", "NlmCategory"=>"RESULTS"} There was a distinct relationship between the amount of Fe-transferrin added and the amount of Fe taken up, which was linear for the primary cultures but significantly reduced for the secondary, tertiary and cataract cultures (252 +/- 21, 169 +/- 14, 153 +/- 14 and 96 +/- 2 ng Fe/mg protein, respectively). Transferring receptor expression in lens cell cultures was reduced 10-fold within 2 days of addition of serum to cells grown in low-Fe, serum-free medium for 1 week. {"Label"=>"CONCLUSIONS", "NlmCategory"=>"CONCLUSIONS"} The reduction of Fe uptake by the subcultured and cataract cell lines probably reflects a decrease in transferrin receptor expression and in the activity of an alternative pathway for Fe transferrin uptake occurring over time. This reduced Fe uptake may result from long-term exposure to relatively high Fe concentration in the media. A reduction in the expression of the transferrin receptor after incubation with high concentrations of Fe supports this conclusion.}, number={6}, journal={GRAEFES ARCHIVE FOR CLINICAL AND EXPERIMENTAL OPHTHALMOLOGY}, author={MCGAHAN, MC and GRIMES, AM and NASISSE, MP and FLEISHER, LN}, year={1995}, month={Jun}, pages={354–359} }
 @article{mcgahan_harned_grimes_fleisher_1994, title={REGULATION OF FERRITIN LEVELS IN CULTURED LENS EPITHELIAL-CELLS}, volume={59}, ISSN={["0014-4835"]}, DOI={10.1006/exer.1994.1140}, abstractNote={In most eukaryotic cells, synthesis of the iron storage protein, ferritin is regulated by iron levels and redox conditions. Proper iron storage is important to protect against damaging iron-catalysed free radical reactions. Although iron-catalysed reactions are believed to contribute to oxidative damage and cataractogenesis, little is known about iron storage in the lens. In this study, ferritin concentration was measured in cultured canine lens epithelial cells. Baseline ferritin concentration ranged from 76-163 ng (mg protein)-1; cells cultured in low-iron media had significantly lower ferritin levels than cells cultured in iron-supplemented media. Addition of a large excess of iron as hemin resulted in an eight-fold increase in ferritin concentration. The iron chelator, Desferal, significantly decreased ferritin concentration. The reducing agent dithiothreitol decreased the hemin-induced increase in ferritin levels, but not baseline levels. In contrast, ascorbic acid induced a large increase in ferritin content. Other studies have shown that induction of ferritin synthesis can protect against oxidative damage. Regulation of ferritin levels may represent a mechanism by which the lens epithelium is protected from oxidative damage. In vivo, epithelial cells are normally exposed to much lower iron concentrations than the cultured lens epithelial cells in this study. However, in pathological circumstances, the iron content and redox state of the aqueous humor is dramatically altered and may affect the steady state levels of ferritin within the lens. This remains to be determined.}, number={5}, journal={EXPERIMENTAL EYE RESEARCH}, author={MCGAHAN, MC and HARNED, J and GRIMES, AM and FLEISHER, LN}, year={1994}, month={Nov}, pages={551–555} }
 @misc{mcgahan_grimes_fleisher_1994, title={TRANSFERRIN INHIBITS THE OCULAR INFLAMMATORY RESPONSE}, volume={58}, ISSN={["0014-4835"]}, DOI={10.1006/exer.1994.1044}, abstractNote={Iron is essential for retinal function but contributes to oxidative stress-mediated degeneration. Iron retinal homeostasis is highly regulated and transferrin (Tf), a potent iron chelator, is endogenously secreted by retinal cells. In this study, therapeutic potential of a local Tf delivery was evaluated in animal models of retinal degeneration.After intravitreal injection, Tf spread rapidly within the retina and accumulated in photoreceptors and retinal pigment epithelium, before reaching the blood circulation. Tf injected in the vitreous prior and, to a lesser extent, after light-induced retinal degeneration, efficiently protected the retina histology and function. We found an association between Tf treatment and the modulation of iron homeostasis resulting in a decrease of iron content and oxidative stress marker. The immunomodulation function of Tf could be seen through a reduction in macrophage/microglial activation as well as modulated inflammation responses. In a mouse model of hemochromatosis, Tf had the capacity to clear abnormal iron accumulation from retinas. And in the slow P23H rat model of retinal degeneration, a sustained release of Tf in the vitreous via non-viral gene therapy efficently slowed-down the photoreceptors death and preserved their function.These results clearly demonstrate the synergistic neuroprotective roles of Tf against retinal degeneration and allow identify Tf as an innovative and not toxic therapy for retinal diseases associated with oxidative stress.}, number={4}, journal={EXPERIMENTAL EYE RESEARCH}, author={MCGAHAN, MC and GRIMES, AM and FLEISHER, LN}, year={1994}, month={Apr}, pages={509–511} }
 @article{mcgahan_fleisher_grimes_1991, title={EFFECTS OF COPPER DEPLETION AND D-PENICILLAMINE TREATMENT ON THE OCULAR INFLAMMATORY RESPONSE}, volume={34}, ISSN={["0065-4299"]}, DOI={10.1007/bf01988736}, abstractNote={Rabbits placed on a copper (Cu)-deficient diet for four weeks had lower plasma Cu concentration, ferroxidase activity, and antioxidant activity than rabbits fed an identical Cu-adequate basal diet. Inflamed aqueous humor from rabbits on the Cu deficient diet also had less Cu, ferroxidase and antioxidant activity than inflamed aqueous humor from control rabbits. These differences mirrored changes in plasma levels. Furthermore, there was an increase in cellular infiltration into the aqueous humor of Cu-deficient rabbits. It is hypothesized that in Cu-deficient rabbits there is an increase in free radical production and formation of chemotactic substances in the eye due to the decreased aqueous humor concentration of the endogenous antioxidant, ceruloplasmin. It is therefore likely that ceruloplasmin plays a protective role in the intraocular inflammatory response.}, number={3-4}, journal={AGENTS AND ACTIONS}, author={MCGAHAN, MC and FLEISHER, LN and GRIMES, AM}, year={1991}, month={Nov}, pages={405–409} }
 @article{mcgahan_grimes_1991, title={SELENIUM CONCENTRATION IN OCULAR-TISSUES AND FLUIDS}, volume={23}, ISSN={["0030-3747"]}, DOI={10.1159/000267087}, abstractNote={A simple, precise method for the analysis of selenium (Se) in ocular fluids and tissues using electrothermal atomic absorption spectroscopy is presented. Se concentrations ranged from 0.23 to 0.41 microgram/g wet weight in the cornea, iris, lens, and retina. The Se concentration in aqueous humor was 0.008 microgram/ml, thus much lower than that of plasma (0.21 microgram/ml). The concentration of protein in aqueous humor is about 1.0% of plasma. Since in plasma, Se is entirely bound to proteins, it is likely that the difference in Se concentration between plasma and aqueous humor reflects the relative distribution of protein between these fluids.}, number={1}, journal={OPHTHALMIC RESEARCH}, author={MCGAHAN, MC and GRIMES, AM}, year={1991}, pages={45–50} }
 @article{mcgahan_fleisher_grimes_1989, title={CLINICAL SIGNS OF ACUTE OCULAR INFLAMMATORY RESPONSE TO ENDOTOXIN ARE NOT ALTERED BY INCREASING ANTIOXIDANT POTENCY OF INTRAOCULAR FLUIDS}, volume={13}, ISSN={["0360-3997"]}, DOI={10.1007/BF00914923}, abstractNote={Plasma antioxidant activity is due in large part to the ferroxidase activity of the copper (Cu) transport protein, ceruloplasmin. Implantation of osmotic pumps containing copper into rabbits resulted in a doubling of Cu concentration, ferroxidase activity, and antioxidant activity in plasma. Blood-ocular barriers essentially prevent the entry of large molecules such as proteins from plasma into the intraocular fluid compartments. However, during ocular inflammation, when these barriers are disrupted, plasma proteins can enter. Twenty-four hours after the induction of ocular inflammation by intraocular injection of endotoxin, the Cu concentration and antioxidant activity of intraocular fluids from the Cu pump animals was twice that of control groups, reflecting the differences in plasma levels. This is the first direct demonstration that alterations in plasma levels of ceruloplasmin can influence the antioxidant potency of the extracellular fluids. Increased intraocular fluid antioxidant activity did not affect the acute anterior segment response to endotoxin. However, it is possible that the time course and resolution of the response is altered by changes in extracellular fluid antioxidant activity. This possibility is currently under investigation.}, number={4}, journal={INFLAMMATION}, author={MCGAHAN, MC and FLEISHER, LN and GRIMES, AM}, year={1989}, month={Aug}, pages={393–400} }
 @article{mcgahan_grimes_fleisher_1989, title={Ferroxidase activity increases dramatically in the aqueous humor during the ocular inflammatory response}, volume={21}, DOI={10.1159/000266811}, abstractNote={Ferroxidase activity was increased in the aqueous humor from inflamed eyes compared to their uninflamed contralateral controls 24 h after intravitreal injection of 10 ng of endotoxin. Changes in ferroxidase activity and copper concentration paralleled each other indicating that the plasma copper transport protein ceruloplasmin (plasma ferroxidase) entered the inflamed aqueous humor from plasma through disrupted blood ocular barriers. The presence of ferroxidase activity would facilitate the removal of potentially damaging, free radical generating Fe+2. Therefore, plasma proteins may perform important protective functions in the inflamed intraocular fluids.}, journal={Ophthalmic Research}, author={McGahan, M. C. and Grimes, A. M. and Fleisher, L. N.}, year={1989}, pages={221–225} }