Publications by authors named "Philip Penfold"

Objective: To evaluate the safety and tolerability of a mineralocorticoid, in a single-dose intravitreal (IVT) injection of 1 mg/0.1 mL and 2 mg/0.1 mL fludrocortisone acetate (FCA) in subjects with geographical atrophy (GA) secondary to age-related macular degeneration.

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The pathogenesis of outer retinal degenerations has been linked to the elevation of cytokines that orchestrate pro-inflammatory responses within the retinal milieu, and which are thought to play a role in diseases such as geographic atrophy (GA), an advanced form of AMD. Here we sought investigate the anti-inflammatory and mechanistic properties of fludrocortisone (FA), as well as triamcinolone acetonide (TA), on Müller cell-mediated cytokine expression in response to inflammatory challenge. In addition, we investigated the neuroprotective efficacy of FA and TA in a photo-oxidative damage (PD), a model of outer retinal degeneration.

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Objective: To examine the morphological features of macular photoreceptors in histologically normal retina from normal donor eyes and eyes with age-related macular degeneration (AMD).

Methods: The macular region was excised from 18 donor eyes (aged 22-96 years) and cryosectioned. Sections were stained with hematoxylin-eosin or double immunolabeled using opsin antibodies or synaptic markers.

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The central retina in primates is adapted for high acuity vision. The most significant adaptations to neural retina in this respect are: 1. The very high density of cone photoreceptors on the visual axis; 2.

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Objective: To determine the safety of a single intravitreal injection of triamcinolone acetonide (4 mg) in patients with subfoveal choroidal neovascularization caused by age-related macular degeneration.

Methods: A double-masked, placebo-controlled, randomized clinical trial was conducted at a public tertiary referral eye hospital. Patients participating had age-related macular degeneration with evidence of choroidal neovascularization, any part of which was classic; age older than 59 years; and best-corrected visual acuity of 20/200 or better.

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Objective: To determine if a single intravitreal injection of 4 mg of triamcinolone acetonide in patients with classic choroidal neovascularization associated with age-related macular degeneration can safely reduce the risk of severe visual loss.

Methods: A double-masked, placebo-controlled, randomized clinical trial was performed in patients 60 years or older who had choroidal neovascularization with any classic component, a duration of symptoms of less than 1 year, and a visual acuity of 20/200 or better. Best-corrected visual acuity, intraocular pressure, and cataract grading were performed before the injection and then at 3, 6, and 12 months.

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Purpose: To demonstrate structural and immunocytochemical changes associated with light-induced degeneration in albino rat retinas and human AMD retinas.

Methods: Retinas from Wistar rats aged 3, 6, or 10 months were examined by immunocytochemistry, with antibodies to neuronal and glial markers. Results were compared with human nonneovascular AMD retinas.

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Retinoblastoma (Rb) is the most common intraocular tumor of childhood. In this study we examined primary Rb specimens and Rb cell lines for the expression of immunoglobulin superfamily (IgSF) antigens: MHC class I and II (MHC-I and MHC-II), neural cell adhesion molecule (NCAM), intercellular adhesion molecule-1 (ICAM-1), and Thy-1, which play an important role in immune system and tumor cell interactions. MHC-I and-II, ICAM-1 (CD54), NCAM (CD56), and Thy-1 (CDw90) immunoreactivity was studied in eight primary Rb biopsy specimens using immunohistochemistry, three using immunoelectron microscopy, and six Rb cell lines using flow cytometry (FCM).

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Purpose: The therapeutic potential of TA, an anti-inflammatory glucocorticoid, for the treatment of exudative retinopathy has been examined in several independent clinical studies. The modulation of permeability and adhesion molecule expression of an epithelial cell line has been described in vitro, with the use of cytokines and triamcinolone acetonide (TA). In the current study, the influence of proinflammatory cytokines and TA on permeability and adhesion molecule expression in human choroidal endothelial cells (CECs) was investigated.

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Glial fibrillary acidic protein (GFAP) is an established marker of retinal glia and has been shown to be modulated by several cytokines and retinal pathology. The influence of a number of factors, including post-mortem delay, storage duration and retinal pathology, on the distribution and morphology of macroglia and GFAP antigenicity was examined in human retina. The effects of these parameters on GFAP expression were estimated using immunohistochemistry, confocal microscopy and image analysis.

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