Showing papers in "Current Eye Research in 2004"
TL;DR: The findings support the use of the new method in the treatment of corneal ulcers after a prolonged preservation especially of the anterior portion of the crosslinked corneas could be demonstrated.
Abstract: Purpose. Collagen-crosslinking using combined riboflavin/UVA treatment has been developed by us as a new treatment for keratoconus by stiffening the collagenous matrix. Recently, we have started to use the same method for the treatment of corneal ulcers. The aim of the present study was to evaluate the influence of the crosslinking treatment on the resistance of the cornea against enzymatic degradation. Methods. 60 enucleated porcine eyes were treated with the photosensitizer riboflavin and UVA-irradiation (370 nm; irradiance of 1, 2 or 3 mW/cm2) for 30 minutes and compared with 20 untreated control eyes. After crosslinking treatment, the corneal buttons were trephined and exposed to pepsin, trypsin and collagenase solutions. The extent of the corneal digestion was monitored daily. Selected cases were examined by light microscopy. Results. The corneal buttons crosslinked with riboflavin/UVA at 3 mW/cm2 were dissolved only by day 13 following pepsin digestion and by day 14 following collagenase treatment v...
629 citations
TL;DR: Mechanisms involved in the upward drift of the tear film after a blink, and in the formation of dry spots, are considered and theoretical predictions of tear film thickness are discussed.
Abstract: Measurements of the thickness of the pre-corneal tear film, pre-lens tear film, post-lens tear film, and the lipid layer on the surface of the tear film are summarized. Spatial and temporal variations in tear film thickness are described. Theoretical predictions of tear film thickness are discussed. Mechanisms involved in the upward drift of the tear film after a blink, and in the formation of dry spots, are considered.
294 citations
TL;DR: The captive-bubble technique provides contact angles that are relevant to on-eye lens wear and minimizes or even eliminates protein adsorption in both advancing and receding contact angles, which are important to lens wettability performance.
Abstract: Introduction. Modern application of soft contact lenses demands safe and comfortable wear over extended time periods up to one month. Lenses that exhibit and sustain complete water wetting allow th...
124 citations
TL;DR: The quantity and conformation of lysozyme deposited on hydrogel contact lens materials is significantly influenced by both lens material and care regimen.
Abstract: Purpose. To determine whether differences in lysozyme deposition and/or activity exist on worn etafilcon and balafilcon contact lenses following care with a polyquaternium-based system (PQ) or a polyhexanide-based system (PHMB). Methods. Following acid-based deposit extraction, lysozyme concentration was determined via Western blotting and lysozyme activity was determined by a micrococcyl assay. Results. Lysozyme deposition on etafilcon lenses was greater following disinfection with the PHMB-based system (1551 ± 371µg/lens vs 935 ± 271µg/lens; p < 0.001). Deposition on balafilcon lenses was not influenced by the care regimen (10 ± 3.5µg/lens vs 10 ± 5µg/lens; p = 0.89). For both materials, the percentage of denatured lysozyme was greater when they were exposed to the PHMB-based system (28 vs 21%; p = 0.05 (etafilcon) and 57 vs 40%; p = 0.04 (balafilcon)). Conclusions. The quantity and conformation of lysozyme deposited on hydrogel contact lens materials is significantly influenced by both lens material...
120 citations
TL;DR: The Test Product was more effective at reducing both the signs and symptoms of dry eye compared to the carboxymethylcellulose containing Control.
Abstract: Purpose. To evaluate the efficacy of a new lubricant eye drop containing polyethylene glycol 400 and propylene glycol demulcents with hydroxypropyl-guar as a gelling agent (Test Product) to a system with carboxymethylcellulose (Control Product) for reducing dry eye signs and symptoms. Methods. Eighty-seven dry eye volunteers were enrolled at seven sites for this six-week, concurrently controlled, double-masked clinical study. Results. The Test Product significantly reduced conjunctival staining (p = 0.025) and temporal corneal staining (p = 0.024) compared to the Control. The Test Product also significantly reduced symptoms of dryness in the morning and evening, compared to the Control (p = 0.015 and p = 0.023, respectively). Subjects in the Test treatment group reported lower frequencies of foreign body sensation and felt their eyes were “refreshed longer” compared to those in the Control group (p = 0.033 and p = 0.037, respectively). Conclusions. The Test Product was more effective at reducing both the ...
112 citations
TL;DR: DM has an additive effect on apoptosis induction by chronic elevation of IOP, which may act as a risk factor for open-angle glaucoma by increasing susceptibility of retinal cells including retinal ganglion cells to apoptosis triggered by additional stresses such as elevated IOP.
Abstract: Purpose. Diabetes mellitus (DM) is a risk factor for open-angle glaucoma, although the mechanistic interrelationship of the two is debatable. The purpose of this study is to test whether DM augments neural apoptosis in rat retina with chronically elevated intraocular pressure (IOP). Methods. Sprague-Dawley rats were made diabetic by intraperitoneal injection of streptozotocin (STZ). At one month after STZ injection, three episcleral veins in one eye were cauterized to elevate IOP. Rats without STZ injection were treated likewise as diabetic controls. At 2 weeks, 1 month, and 2 months after cauterization, the retina was dissected, flat-mounted, and subjected to terminal dUTP nick end labeling (TUNEL) staining. TUNEL positive cells per unit area of the whole retina were measured. Results. DM did not affect base line IOP or augment IOP elevation due to episcleral vein cauterization. TUNEL positive cells, which primarily consisted of the neurons and glial cells in the inner retina including retinal ganglion c...
89 citations
TL;DR: Pretreatment and early posttreatment with EGb 761 is an effective neuroprotectant in a rat model of chronic glaucoma, and retention of surviving retinal ganglion cells in whole mounted retinas is estimated.
Abstract: Purpose To investigate the effect of Ginkgo biloba extract (EGb 761) against neurotoxicity of retinal ganglion cells of rats with chronic moderately elevated intraocular pressure (IOP) Methods Unilateral chronic moderately elevated IOP was produced in rats by cautery of three episcleral vessels Secondary degeneration was measured with and without EGb 761 for 5 months At 5 months, retinal ganglion cells were labeled with a fast blue tracer applied to both superior colliculi Densities of surviving retinal ganglion cells were estimated by counting fast blue labeled cells in whole mounted retinas Results When compared with their contralateral control eyes with normal IOP, in the peripheral retina, retinal ganglion cell loss in eyes with chronic, moderately elevated IOP was 298 ± 15% (n = 5) at 5 months in untreated animals and 46 ± 45% (n = 5) at 5 months in treated animals with EGb 761 Conclusions Pretreatment and early posttreatment with EGb 761 is an effective neuroprotectant in a rat model o
88 citations
TL;DR: It is demonstrated that chloroquine disrupts lysosomal function in retinal neurons and RPE and provides a clear pathogenic basis for the functional defects experienced by patients with chlorquine retinopathy.
Abstract: Chronic use of chloroquine has been shown to induce numerous pathophysiological defects in the retina. This drug has the ability to alter pH of intracellular compartments and lysosomal function of the retinal pigment epithelium (RPE) and retinal neurons may constitute the basis of chloroquine retinopathy. The aim of the current study was to investigate pathogenic alterations in retinal cells continuously exposed to chloroquine using appropriate in vivo and in vitro models. Male hooded Lister rats were implanted with osmotic mini pumps which released chloroquine continuously over a period of seven days. The eyes were processed for electron microscopy and ultrastructural abnormalities determined in the neural retina and quantified using stereology in the retinal pigment epithelium (RPE). RPE were also exposed to chloroquine in vitro and lysosomal pH changes were investigated using a pH sensitive probe. Degradative capacity was also analysed using FITC labeled rod outer segments (ROS). Chloroquine-treated animals displayed several ultrastructural abnormalities including numerous membranous cytoplasmic bodies (MCBs) in retinal neurons. Cone photoreceptors displayed numerous MCBs although rods did not. The RPE of the treated groups all showed significantly higher numbers of lysosomal associated organelles (LAO) than the control group (p < 0.001). The in vitro experiments demonstrated chloroquine-mediated rises in lysosomal pH and an increase in lysosome/phagosome accumulation of ROS in the chloroquine treated group (p < 0.01). The current study demonstrates that chloroquine disrupts lysosomal function in retinal neurons and RPE. The evidence presented provides a clear pathogenic basis for the functional defects experienced by patients with chloroquine retinopathy.
86 citations
TL;DR: Pre-clinical studies of a new artificial tear product containing the novel gelling agent hydroxypropyl-guar and two demulcents suggest that the product will be effective in providing superior relief for the dry eye sufferer.
Abstract: Purpose. Pre-clinical studies of a new artificial tear product (SystaneTM Lubricating Eye Drops Alcon Laboratories, Inc., Fort Worth, TX) containing the novel gelling agent hydroxypropyl-guar (HP-guar) and two demulcents, polyethylene glycol 400 (PEG) and propylene glycol (PG) were conducted to determine the ability of the product to protect ocular surface epithelial cells from desiccation in vivo and in vitro, and to promote recovery of the damaged corneal epithelial barrier in vivo. Other leading artificial tear products were also evaluated as comparators to determine the relative effectiveness of different polymer systems. Methods. Damage due to desiccation was assessed by measuring corneal uptake of methylene blue compared to untreated corneas. Corneas of anesthetized rabbits were treated with the new artificial tear product and subjected to desiccation by holding the eyelids open for 2 hours with a speculum. Control eyes were subjected to desiccation without application of a tear formulation. To meas...
80 citations
TL;DR: The results from this study showed that enhanced expression of VEGF and PKC in early diabetes and the blood-retinal barrier breakdown of early diabetic retinopathy induced by PKC activation may be partly due to the upregulation of V EGF.
Abstract: Purpose. To investigate (1) the mechanism of blood-retinal barrier breakdown induced by protein kinase C (PKC) activation (2) the relationship between PKC activation and vascular endothelial growth factor (VEGF) in 2-week streptozotocin-induced diabetes. Methods. Retinal PKC activities, retinal and vitreous concentration of VEGF protein were conducted by enzyme-linked immunoabsorbent assay (ELISA). Retinal VEGF mRNA expression was analyzed by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). Blood-retinal barrier breakdown was quantified using the Evans blue technique. Alteration of retinal VEGF and blood-retinal barrier were observed after intravitreal injection of PKC inhibitor, GF109203X, in 2-week diabetic rats. Results. Two weeks of diabetes in rats resulted in elevation of retinal PKC specific activities, retinal and vitreous VEGF, and retinal vascular permeability. Retinal VEGF and retinal vascular permeability were decreased after intravitreal injection of GF109203X (10 -...
73 citations
TL;DR: This study has identified ACE2 gene and catalytically active protein in the rodent retina and found that in diabetes, the major changes were a decrease in ACE but an increase in ACE2 enzymatic activity.
Abstract: Purpose. An active renin-angiotensin system has been found in the retina of rats and humans. Angiotensin-converting enzyme 2 (ACE2) is a recently discovered enzymatic homologue of Angiotensin-converting enzyme (ACE) that may be an important new component of the renin-angiotensin system (RAS). This study assesses the involvement of ACE2 in the normal and diabetic rodent retina and its modulation by ACE inhibition.Methods. Sprague-Dawley rats were randomised into three groups, control, diabetes, and diabetes plus ramipril, with diabetes induced with the β-cell toxin streptozocin and the study run for 24 weeks. ACE2 and ACE gene levels were measured using quantitative real-time polymerase chain reaction (QRT-PCR), ACE2 protein expression was confirmed by Western blotting, and ACE and ACE2 catalytic activity were measured using specific activity assays in the rat retina. Localisation of ACE2 mRNA and protein were determined by in situ hybridisation and immunohistochemistry, respectively.Results. ACE mRNA leve...
TL;DR: This study tested the hypothesis that the proliferative R28 retinal cell line contains subpopulations of cells that express neuronal mRNAs and proteins characteristic of CNS neurons, and found that these cells retain functional neuronal properties that may prove useful in future studies of neuronal differentiation and development.
Abstract: Purpose. Proliferative retinal progenitor cells that express neuronal characteristics are potentially useful for developmental studies and as experimental graft material. The continuously-growing R28 retinal cell line has been distributed to over 60 laboratories for a variety of studies, yet has not been fully characterized. In this study, we tested the hypothesis that the proliferative R28 retinal cell line contains subpopulations of cells that express neuronal mRNAs and proteins characteristic of CNS neurons. Methods. To this end, we sought to determine the potential retinal, neuronal, and growth-related characteristics of this retinal cell line through gene expression profiling, coupled with confirmatory immunocytochemistry and electrophysiology. Results. Despite expression of growth-stimulatory oncogenes and growth-promoting factors, subpopulations of R28 cells express abundant retinal and neuronal markers, as well as the functional capacity to respond to specific neurotransmitters such as dopamine, a...
TL;DR: AAV-mediated delivery of bFGF and BDNF can promote retinal cell survival following excitotoxic insult, and these growth factors were neuroprotective against NMDA injection 1 month post-treatment.
Abstract: Purpose. Brain-derived neurotrophic factor (BDNF) and basic fibroblast growth factor (bFGF) hold much promise for the protection of retinal ganglion cells against excitotoxic cell death. We tested the possibility of delivering these growth factors to retinal ganglion cells via an adeno-associated viral (AAV) vector and tested their efficacy in two models of excitotoxicity.Methods. Rat retinas were infected with AAV vectors encoding bFGF or BDNF. A control vector containing green fluorescent protein (GFP) was injected in the contralateral eye. Eyes were subjected to either an intravitreal injection of N-methyl-D-aspartate (NMDA) or optic nerve crush, and ganglion cell survival was evaluated.Results. AAV.CMV.bFGF and AAV.CBA.BDNF were neuroprotective against NMDA injection 1 month post-treatment. Additionally, AAV.CMV.bFGF was protective against optic nerve crush.Conclusion. AAV-mediated delivery of bFGF and BDNF can promote retinal cell survival following excitotoxic insult.
TL;DR: The evidence that lifetime oxidative stress plays an important role in the development of ARM is now compelling and the positive outcomes in the Age-Related Eye Diseases Study have given hope that modulation of the antioxidant balance through supplementation can help prevent progression of ARM to AMD.
Abstract: Age-related maculopathy (ARM) is a common clinical entity. The late-stage manifestations of ARM, which are known as age-related macular degeneration (AMD), have devastating consequences for vision. Various risk factors have been identified in the development of the condition, which are consistent with the premise that oxidative stress plays an important role in its pathogenesis. Thus, the possibility that antioxidant balance can be manipulated through diet or supplementation has created much interest. Associations between diet and nutrition and the clinical features of ARM have been described. Scrutiny of the literature shows consistency in the report of notable reductions in serum micronutrients in wet AMD, however, the evidence for causation is still circumstantial. In this comprehensive review of the clinical literature, we have assessed the evidence for a link between diet and nutrition as risk factors for the development of ARM and AMD. All published case control, population-based, and interventional studies on ARM were examined. Although initial support appeared to be moderate and somewhat contradictory, the evidence that lifetime oxidative stress plays an important role in the development of ARM is now compelling. The positive outcomes in the Age-Related Eye Diseases Study, a major controlled clinical trial, have given hope that modulation of the antioxidant balance through supplementation can help prevent progression of ARM to AMD.
TL;DR: Design of amino acid prodrugs seems to be an attractive strategy to enhance the solubility of the otherwise poorly aqueous soluble compounds and also to afford a targeted and possibly enhanced delivery of the active drug.
Abstract: Purpose. The aim of this study was to explore the feasibility of improvement of ocular bioavailability of the antiviral agent acyclovir by designing amino acid prodrugs targeted to the amino acid transporters on the rabbit cornea. Materials and methods. Transcorneal flux of two water-soluble amino acid ester prodrugs of acyclovir (ACV), γ-glutamate-ACV (EACV) and L-tyrosine-ACV (YACV), was studied across freshly excised rabbit cornea. Chemical and enzymatic hydrolysis studies of the two prodrugs were also conducted. Results. EACV inhibited the uptake of [3H]L-Arg in rabbit primary corneal epithelial cells (rPCECs). The compound also exhibited longer half-life (t1/2) in cornea in comparison to YACV. Transcorneal flux of EACV was observed to be concentration-, energy-, and sodium-dependent and independent of pH within the range studied. EACV transport was inhibited by neutral and cationic amino acids, L-ornithine (specific for cationic amino acids), and BCH (2-aminobicyclo-[2,2,1]-heptane-2-carboxylic-acid)...
TL;DR: Most orthokeratology lens wearers with low to moderate myopia and low astigmatism enjoyed reasonably good unaided post-orthokersatology vision in the daytime.
Abstract: Purpose. To determine which clinical tests are useful in orthokeratology aftercare examination, and to examine the objective and subjective characteristics of a group of orthokeratology lens wearers. Methods. Thirty orthokeratology subjects (8–19 years) who had been wearing orthokeratology lenses for over 12 months were recruited. Autorefraction, corneal topography, retinoscopy, subjective refraction and biomicroscopy were performed. Only left eyes results were analysed. Subjective ratings of symptoms and problems experienced by subjects were obtained using a questionnaire. Results. Autorefraction yielded higher residual sphere and residual cylinder by –0.54 D and –0.39 D respectively while retinoscopy yielded higher residual sphere and residual cylinder by –0.20D and –0.03 D respectively. Corneal toricity measured by autokeratometry and corneal topography overpredicted the residual cylinder by –2.02D and –2.08D respectively. The mean ± SD residual spherical equivalent refractive error was –0.11 ± 0.57 D ...
TL;DR: Although the mfERG correlated significantly with the desaturated D-15 in early ARM, suggesting it operates at a sensitive level, it failed to discriminate between the control and ARM groups.
Abstract: Purpose. To investigate the multifocal electroretinogram (mfERG) and subjective function in early age-related maculopathy (ARM). Methods. Seventeen subjects with early ARM with visual acuity (VA) of 6/12 or better and 20 age-matched control subjects were examined. We assessed mfERGs, high and low contrast distance VA, near VA, low luminance VA, contrast sensitivity, saturated and desaturated Panel D-15 and visual fields (mean sensitivity). The mfERG responses were analysed by comparing central-overall (method 1) and superior-inferior (method 2) ratios. Results. The mfERG did not discriminate between the groups whereas colour vision (tritan deficiency), contrast sensitivity, and high contrast and low contrast VA showed significantly reduced responses for the early ARM group compared with the control group (p ≤ 0.01). The mfERG first-order kernel responses correlated significantly with the desaturated D-15 in both methods (r = −0.5, p ≤ 0.05). Fundus grading was not correlated with the mfERG measures. Con...
TL;DR: This is the first time that ILM peeling has been performed in an animal model, and the cat model, which has provided essential data on retinal detachment for years, and which is known for the validity of the results in terms of comparability with the human retina, is performed.
Abstract: (2004). Ultrastructure of the vitreoretinal interface following removal of the internal limiting membrane using indocyanine green. Current Eye Research: Vol. 29, No. 4-5, pp. 319-320.
TL;DR: Although MG do not classically activate following LPS/IFNγ stimulation, their migration is sustained via CD200R stimulation maintaining their potential to migrate in response to injury.
Abstract: Purpose. Retinal microglia (MG) migrate in response to injury, degeneration and inflammation dependent upon both soluble and cognate signals they receive. Previously we found that lipopolysaccharide/interferon-γ (LPS/IFNγ) stimulation induces a paradoxical IL-10 mediated suppression of MG migration from retinal explants. Given the high expression of neuronal CD200, which can induce down regulation of CD200 receptor-positive MG activation and neuronal fractalkine expression potentially stimulating MG migration, we wished to further examine their respective roles in the maintenance of MG activation and migration. Methods. A human retinal explant model of MG migration was used. CD200 receptor and fractalkine receptor stimulation was achieved by addition to explants of CD200:Fc fusion protein and recombinant cytokine respectively, with or without LPS-IFNγ stimulation that is known to suppress migration. Cell migration and cell activation (iNOS expression) was counted and assessed by numbers of CD45+ cells by ...
TL;DR: Salicylic acid demonstrated potential as a compound for incorporation into anti-bacterial strategies to prevent bacterial contamination of contact lenses and was the least cytotoxic NSAID.
Abstract: Purpose. To investigate non-steroidal anti-inflammatory agents (NSAIDs), salicylic acid, sodium diclofenac and ketorolac for inhibition of bacterial colonization of contact lenses (CL) and human corneal epithelial cells (HCE). Methods. CLs pre-colonised with Pseudomonas aeruginosa, Haemophilus influenzae, Staphylococcus epidermidis and Streptococcus pneumoniae were exposed overnight to NSAIDs and the number of viable bacteria on the CLs were calculated. Cytotoxicity of NSAIDs to HCE cells was evaluated with the MTT assay. Viable counts were used to measure the adhesion of P. aeruginosa and S. epidermidis to HCE cells in the presence of the least cytotoxic NSAID. Results. All NSAIDs significantly decreased bacterial colonization of CLs in a dose-dependent manner. Salicylic acid (100 mM) completely inhibited colonisation of all species tested and was the least cytotoxic. Salicylic acid also prevented adhesion of P. aeruginosa and S. epidermidis to HCE (60% and 58% inhibition at 60 mM at 2 hours). Conclusion...
TL;DR: In this paper, the in vitro and in vivo proliferative capacity of human conjunctival epithelial cells cultured in serum-free media, and compared this with current methods that utilize serum-containing media and 3T3 feeder layers, were investigated.
Abstract: Purpose. To investigate the in vitro and in vivo proliferative capacity of human conjunctival epithelial cells cultured in serum-free media, and to compare this with current methods that utilize serum-containing media and 3T3 feeder layers. Methods. Human conjunctival epithelial cells were cultivated in serum-free media alone, serum-free media with a 3T3 feeder layer, and serum-containing media with a 3T3 feeder layer. The areas of outgrowth, colony-forming efficiencies and number of population doublings were compared. The in vivo proliferative potential was assessed by analyzing the number of cells generated by the implantation of cultured cells into athymic mice. Cultured cells were evaluated for the expression of cytokeratins K3, K4, K12, K19, as well as the gel-forming goblet cell mucin, MUC5AC. Results. Cells cultivated in serum-free media, serum-free media and feeder cells, and serum-containing media and feeder cells achieved colony-forming efficiencies of 14.5 ± 4.1%, 10.1 ± 3.1%, and 20.4 ± 6.7%, ...
TL;DR: Not only epithelial cells but also stromal keratocytes are efficient producers of CCL20 in the cornea and recruit CCR6-expressing cells such as dendritic cells into inflamed cornea.
Abstract: Purpose. CC chemokine-ligand 20 (CCL20) is known to be selectively expressed by surface-lining mucosal epithelial cells and skin epidermal keratinocytes and to attract cells such as immature dendritic cells and effector T cells via CCR6. This study evaluated the ability of corneal epithelial cells and stromal keratocytes to produce CCL20 in vitro and in vivo. Methods. Human corneal epithelial cells (HCE) and corneal keratocytes (HCK) were treated without or with various cytokines and expression of CCL20 mRNA and secreion of its protein were evaluated by RT-PCR and ELISA. Induction of CCL20 mRNA in HCE and HCK was also examined upon in vitro infection with HSV-1. Using a mouse model of herpetic stromal keratitis (HSK), induction of CCL20 expression and accumulation of cells expressing CCR6 were evaluated by RT-PCR and immunohistochemistry. Results. Not only corneal epithelial cells but also stromal keratocytes efficiently expressed CCL20 mRNA and protein upon stimulation with IL-1s and TNF-a. In vitro infe...
TL;DR: Photocoagulation for DME has a beneficial effect on patients' subjective perception of visual function and the use of vision-targeted health status questionnaires appears to provide a more comprehensive overview of individuals' daily well-being following laser treatment.
Abstract: Purpose. To evaluate the effect of laser photocoagulation for diabetic macular oedema (DME) on patients' Vision Related Quality Of Life (VR-QOL) and to investigate associations between changes in self reported VR-QOL and changes in visual acuity following application of laser treatment. Methods. Prospective cohort study of 55 subjects who underwent laser treatment for DME. Eligible patients with no history of previous laser photocoagulation self administered the 51-item field-test version of the National Eye Institute Visual Function Questionnaire (NEI-VFQ) prior to treatment and 3 months following the last session of laser application. Visual acuity was measured by means of the Early Treatment of Diabetic Retinopathy (ETDRS) chart. Multi-item scales rating different aspects of VR-QOL were compared prior and after photocoagulation and the change in questionnaire's composite score following treatment was correlated to change in visual acuity and other determinants previously reported as risk factors in the...
TL;DR: The chicken cornea’s morphology and wound healing response render it a useful model for corneal wound healing investigations.
Abstract: Purpose. To evaluate the chicken cornea as a model for corneal wound healing research. Methods. We conducted studies on normal chicken corneas and on corneas following mechanical debridement and photorefractive keratectomy (PRK). Results. The chicken cornea possesses six distinct layers that resemble the layers of the human cornea, including a substantial Bowman’s layer measuring 5.2 ± 0.3µm thick. Reepithelialization time was 44.8 ± 1.1 hours with a sliding rate of 75.3 ± 3.2µm/hour following mechanical debridement and 54.4 ± 2.8 hours with a sliding rate of 63.3 ± 3.2µm/hour for PRK-treated corneas. Biomicroscopic haze post-PRK peaked at 4–6 weeks and regressed until 20 weeks post-PRK. Histologic and clinical observations of wound healing strongly paralleled that noted in humans. Conclusion. The chicken cornea’s morphology and wound healing response render it a useful model for corneal wound healing investigations.
TL;DR: Widespread nectin-1 expression in the eye suggests that this receptor may play a role in the pathogenesis of ocular HSV infections and is widely expressed in murine ocular tissues.
Abstract: Purpose. Nectin-1 belongs to the immunoglobulin superfamily, mediates cell-cell adhesion in cadherin-based adherens junctions, and acts as a receptor for herpes simplex virus (HSV). The goals of th...
TL;DR: DSF eye drops effectively prevent the development of selenite-induced cataracts and enhance both the solubility of DSF in aqueous eye drops and permeability of the drug into the rabbit eye.
Abstract: Purpose. To test the effect of aqueous eye drops containing a high concentration of disulfiram (DSF) in a cyclodextrin-based drug delivery system. This system increases both the drug solubility in aqueous eye drops and the permeability of drug into the rabbit eye, by the formation of a drug-cyclodextrin inclusion complex, and so enhances the ocular bioavailability and anti-cataract effect of DSF. Methods. The DSF and hydroxypropyl-β-cyclodextrin (HPβCD) inclusion (DSF/HPβCD) was studied using solubility methods, IR spectra and X-ray diffraction patterns. Suitable formulations for DSF eye drops were first identified by a trans-corneal penetration experiment in vitro. Finding a new p-bromophenacyl bromide (p-BPB) derivative reagent for diethyldithiocarbamic acid (DDC), which was a metabolite of DSF, allowed precise determination of the contents of DSF in aqueous humor. The ocular bioavailability was calculated by a transcorneal experiment of DSF in vivo. The lens opacity of a selenite-induced cataract in ra...
TL;DR: Evidence is provided that bacterial infection in the cornea of ICE−/− mice induces a reduced inflammatory response by: reduction in PMN and cytokines and chemokines that attract these cells to the corneal infection; enhanced apoptotic cell death in the infected epithelium; and increased IL-1Ra levels.
Abstract: Purpose. Antibody neutralization studies have shown that in Pseudomonas aeruginosa corneal infection, IL-1β is critical to regulation of the host inflammatory response, but mechanisms remain undetermined. To elucidate these mechanisms, caspase-1 knockout (ICE−/−) mice, that do not release mature IL-1β after endotoxin challenge, were tested. Methods. Clinical scores, MPO activity (for PMN quantitation), bacterial plate count, semiquantitative RT-PCR, ELISA and TUNEL staining were used to characterize the inflammatory response after infection in knockout and C57BL/6 (B6) wild type mice. Results. Clinical scores were significantly reduced in ICE−/− vs. B6 mice at 3, 5 and 7 days postinfection (p.i.). The decreased inflammatory response of ICE−/− mice was striking at 1 day p.i., and bacterial load also was significantly reduced in the cornea of the knockout mice at 3-7 days p.i. Knockout mice exhibited significantly increased mRNA and protein levels for IL-1Ra, the physiological regulator of IL-1 activity, an...
TL;DR: A combination of PCR and immunofluorescence assay appears to be the most suitable choice of tests for diagnosis of HSV-1 keratitis, while detection of MNGC by Giemsa staining procedure may give a presumptive diagnosis of suspected viral infection.
Abstract: Purpose. To evaluate three different diagnostic tests against the gold standard of viral isolation, in the diagnosis of HSV1 keratitis. Methods. Corneal scrapings from 170 patients with clinically suspected HSV keratitis were tested by; 1) Giemsa staining procedure for the presence of multinucleated giant cells and lymphocytes, 2) immunofluorescence assay for HSV-1 antigen, 3) polymerase chain reaction (PCR) for HSV-1 DNA and 4) virus isolation by shell vial culture in SIRC (Rabbit corneal epithelial cell line). The results of the former three tests were compared among 14 cases that were culture positive and 156 cases that were culture negative for HSV-1. Results. The sensitivity of PCR was 100%, while IFA and Giemsa had sensitivities of 85.7% and 57.1% respectively. The specificity of PCR, IFA and Giemsa were found to be 67.9%, 85.3% and 85.9% respectively. Conclusions. In the present study, a combination of PCR and immunofluorescence assay appears to be the most suitable choice of tests for diagnosis of HSV-1 keratitis, while detection of MNGC by Giemsa staining procedure may give us a presumptive diagnosis of suspected viral infection.
TL;DR: The results suggest that the mechanism for anterior ocular inflammation may be due to up-regulation of COX-2, which is well correlated with increased mRNA levels.
Abstract: Purpose Using two animal models to determine which isoform of cyclooxygenase (COX), constitutive COX-1 or inducible COX-2, is involved in the progression of anterior ocular inflammation. Methods Lambda-carrageenan (500 mg/eye) or bacterial lipopolysaccharide (LPS; 3 mg/eye) was injected into rat conjunctiva to induce conjunctivitis. Vascular permeability in inflamed conjunctiva was measured by uptake of systemic Evans blue. Changes in mRNA for COX-1 and COX-2 in conjunctiva were detected by RT-PCR. Changes in COX-2 protein were detected by immunoblotting after immunoprecipitation. To assess involvement of COX-2 in carrageenan and LPS-induced conjunctivitis, NS-398 (a selective COX-2 inhibitor) or indomethacin (non-selective COX inhibitor) was topically administrated at 15 and 30 minutes before inflammatory stimulator-injection. Results In the carrageenan-injected model, the dye content of conjunctiva (12.4 +/- 2.8 mg/eye) was significantly increased 4 hours after injection compared to saline-injected control rats (3.7 +/-1.1 mg/eye). mRNA for COX-2 was significantly increased by 2 hours and gradually increased until 24 hours; COX-1 mRNA did not show major changes until 24 hours after injection. COX-2 protein was markedly elevated 4 hours after injection of carrageenan. COX-2 protein levels were well correlated with increased mRNA levels. In the LPS-injected model, the dye content of conjunctiva (5.8 +/- 1.2 mg/eye) was significantly increased 4 hours after injection compared to saline-injected control rats (3.1 +/- 0.6 mg/eye). Expression of COX-2 mRNA was increased 1 hour after injection, peaked at 2 hours, and decreased at 4 hours. mRNA for COX-1 did not change by 24 hours. COX- 2 protein increased 2 hours after injection of LPS. COX-2 protein levels were well correlated with increased mRNA. Topical administration of 1% NS-398 exhibited strong inhibition of dye-leakage into conjunctiva 4 hours after injection of carrageenan or LPS, since 59% or 83% of dye-uptake were inhibited, respectively. 1% of indomethacin eye drops showed only a minimal effect. Conclusions These results suggest that the mechanism for anterior ocular inflammation may be due to up-regulation of COX-2.
TL;DR: Hyaluronidase, chondroitinase, and plasmin are good candidates for enzyme-assisted vitrectomy and retinal structural damage was very rarely seen, safety concerns will have to be investigated further.
Abstract: Purpose. Facilitation of vitrectomy by vitreolytic enzymes may be of great value in complicated or office-procedure vitreo-retinal surgery. In this study, we quantified and compared the effect of hyaluronidase, chondroitinase, and plasmin pre-incubation on vitrectomy rate and explored potential retinal damage. Methods. Freshly enucleated pigs eyes were incubated (1 or 3 hours) with an intravitreally injected enzyme or control solution. Enzyme doses were 100 and 1000 U for hyaluronidase, 1 and 2 U for chondroitinase, 3 and 30 U for plasmin. The eyes were weighed before and after 10 minutes of one-port vitrectomy, the difference representing the amount of removed vitreous. Light microscopy was used to assess potential damage to the retina. Results. All enzymes significantly increased the amount of removed vitreous at all doses and incubation periods. The highest increase was found with hyaluronidase 1000 U, 3 hours, the lowest with chondroitinase 1 U, 1 hour. Damage occasionally occurred to the internal lim...