74 resultados para Blindness monocular
Resumo:
The housing dimension in Kolkata has been changing in recent years. Since 1991, the city has initiated housing reform that has taken many forms and manifestations characterized by the reduction in social allocation, cutbacks in public funding and promotion of a real estate culture in close partnership between the state and private actors. There has been increasing concern about the housing condition of the poor in the deserted slums and bustee settlements amidst the evident ‘poor blindness’ in housing and investment policies. Against this background the paper discusses self-help housing in Kolkata. It seeks to answer a simple question – why the concept of self-help has not been recognised as a viable policy option for a city with widespread slums and bustee settlements by visiting the complex urban context of Kolkata set within the city's politics, poverty and policies. The paper concludes that there is a need to recognise the existing structural duality in the city and support self-help housing as a parallel housing approach.
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The retina is exposed to a lifetime of potentially damaging environmental and physiological factors that make the component cells exquisitely sensitive to age-related processes. Retinal ageing is complex and a raft of abnormalities can accumulate in all layers of the retina. Some of this pathology serves as a sinister preamble to serious conditions such as age-related macular degeneration (AMD) which remains the leading cause of irreversible blindness in the Western world.
The formation of advanced glycation end products (AGEs) is a natural function of ageing but accumulation of these adducts also represents a key pathophysiological event in a range of important human diseases. AGEs act as mediators of neurodegeneration, induce irreversible changes in the extracellular matrix, vascular dysfunction and pro-inflammatory signalling. Since many cells and tissues of the eye are profoundly influenced by such processes, it is fitting that advanced glycation is now receiving considerable attention as a possible pathogenic factor in visual disorders.
This review presents the current evidence for a pathogenic role for AGEs and activation of the receptor for AGEs (RAGE) in initiation and progression of retinal disease. It draws upon the clinical and experimental literature and highlights the opportunities for further research that would definitively establish these adducts as important instigators of retinal disease. The therapeutic potential for novel agents that can ameliorate AGE formation of attenuate RAGE signalling in the retina is also discussed.
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PURPOSE: Age-related macular degeneration (AMD) is the most common cause of blindness in older people in developed countries, and risk factors for this condition may be classified as genetic and environmental. Apolipoprotein E is putatively involved in the transport of the macular pigment (MP) carotenoids lutein (L) and zeaxanthin (Z) in serum and may also influence retinal capture of these compounds. This study was designed to investigate the relationship between macular pigment optical density (MPOD) and ApoE genotype. METHODS: This was a cross-sectional study of 302 healthy adult subjects. Dietary intake of L and Z was assessed by food frequency questionnaire, and MPOD was measured by customized heterochromatic flicker photometry. Serum L and Z were measured by HPLC. ApoE genotyping was performed by direct polymerase chain reaction amplification and DNA nucleotide sequencing from peripheral blood. RESULTS: Genotype data were available on 300 of the 302 (99.3%) subjects. The mean (+/- SD) age of the subjects in this study was 47.89 +/- 11.05 (range, 21-66) years. Subjects were classed into one of three ApoE genotype groups, as follows: group 1, epsilon2epsilon2 or epsilon2epsilon3; group 2, epsilon3epsilon3; group 3, epsilon2epsilon4 or epsilon3epsilon4 or epsilon4epsilon4. All three groups were statistically comparable in terms of age, sex, body mass index, cigarette smoking, and dietary and serum levels of L and Z. There was a statistically significant association between ApoE genotype and MPOD. Subjects who had at least one epsilon4 allele had a higher MPOD across the macula than subjects without this allele (group 1 MPOD area, 0.70 +/- 0.40; group 2 MPOD area, 0.67 +/- 0.42; group 3 MPOD area, 0.85 +/- 0.46; one-way ANOVA, P = 0.014. CONCLUSIONS: These results suggest that ApoE genotype status is associated with MPOD. This association may explain, at least in part, the putative protective effect of the epsilon4 allele for AMD and is consistent with the view that apolipoprotein profile influences the transport and/or retinal capture of circulating L and/or Z.
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PURPOSE: Retinitis pigmentosa (RP) causes hereditary blindness in adults (prevalence, approximately 1 in 4000). Each of the more than 30 causative genes identified to date are responsible for only a small percentage of cases. Genetic diagnosis via traditional methods is problematic, and a single test with a higher probability of detecting the causative mutation would be very beneficial for the clinician. The goal of this study therefore was to develop a high-throughput screen capable of detecting both known mutations and novel mutations within all genes implicated in autosomal recessive or simplex RP. DESIGN: Evaluation of diagnostic technology. PARTICIPANTS AND CONTROLS: Participants were 56 simplex and autosomal recessive RP patients, with 360 population controls unscreened for ophthalmic disease. METHODS: A custom genechip capable of resequencing all exons containing known mutations in 19 disease-associated genes was developed (RP genechip). A second, commercially available arrayed primer extension (APEX) system was used to screen 501 individual previously reported variants. The ability of these high-throughput approaches to identify pathogenic variants was assessed in a cohort of simplex and autosomal recessive RP patients. MAIN OUTCOME MEASURES: Number of mutations and potentially pathogenic variants identified. RESULTS: The RP genechip identified 44 sequence variants: 5 previously reported mutations; 22 known single nucleotide polymorphisms (SNPs); 11 novel, potentially pathogenic variants; and 6 novel SNPs. There was strong concordance with the APEX array, but only the RP genechip detected novel variants. For example, identification of a novel mutation in CRB1 revealed a patient, who also had a single previously known CRB1 mutation, to be a compound heterozygote. In some individuals, potentially pathogenic variants were discovered in more than one gene, consistent with the existence of disease modifier effects resulting from mutations at a second locus. CONCLUSIONS: The RP genechip provides the significant advantage of detecting novel variants and could be expected to detect at least one pathogenic variant in more than 50% of patients. The APEX array provides a reliable method to detect known pathogenic variants in autosomal recessive RP and simplex RP patients and is commercially available. High-throughput genotyping for RP is evolving into a clinically useful genetic diagnostic tool.
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Endothelial cell association with vascular basement membranes is complex and plays a critical role in regulation of cell adhesion and proliferation. The interaction between the membrane-associated 67-kd receptor (67LR) and the basement membrane protein laminin has been studied in several cell systems where it was shown to be crucial for adhesion and attachment during angiogenesis. As angiogenesis in the pathological setting of proliferative retinopathy is a major cause of blindness in the Western world we examined the expression of 67LR in a murine model of hyperoxia-induced retinopathy that exhibits retinal neovascularization. Mice exposed to hyperoxia for 5 days starting at postnatal day 7 (P7) and returned to room air (at P12) showed closure of the central retinal vasculature. In response to the ensuing retinal ischemia, there was consistent preretinal neovascularization starting around P17, which persisted until P21, after which the new vessels regressed. Immunohistochemistry was performed on these retinas using an antibody specific for 67LR. At P12, immunoreactivity for 67LR was absent in the retina, but by P17 it was observed in preretinal proliferating vessels and also within the adjacent intraretinal vasculature. Intraretinal 67LR immunoreactivity diminished beyond P17 until by P21 immunoreactivity was almost completely absent, although it persisted in the preretinal vasculature. Control P17 mice (not exposed to hyperoxia) failed to demonstrate any 67LR immunoreactivity in their retinas. Parallel in situ hybridization studies demonstrated 67LR gene expression in the retinal ganglion cells of control and hyperoxia-exposed mice. In addition, the neovascular intra- and preretinal vessels of hyperoxia-treated P17 and P21 mice labeled strongly for 67LR mRNA. This study has characterized 67LR immunolocalization and gene expression in a murine model of ischemic retinopathy. Results suggest that, although the 67LR gene is expressed at high levels in the retinal ganglion cells, the mature receptor protein is preferentially localized to the proliferating retinal vasculature and is almost completely absent from quiescent vessels. The differential expression of 67LR between proliferating and quiescent retinal vessels suggests that this laminin receptor is an important and novel target for future chemotherapeutic intervention during proliferative vasculopathies.
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Diabetic retinopathy (DR) is the most widespread complication of diabetes mellitus and a major cause of blindness in the working population of developed countries. The clinicopathology of the diabetic retina has been extensively studied, although the relative contribution of the various biochemical and molecular sequelae of hyperglycemia remains ill defined. Many neural and microvascular abnormalities occur in the retina of short-term diabetic animals but it remains uncertain how closely these acute changes relate to chronic human disease. It is important to determine the relationship between alterations observed within the first weeks or months in short-term aminal models, and human disease, where clinically manifest retinopathy occurs only after durations of diabetes measured in years. This review is focused on the retinal microvasculature, although it should be appreciated that pathological changes in this system often occur in parallel with abnormalities in the neural parenchyma that may be derivative or even causal. Nevertheless, it is useful to reevaluate the microvascular lesions that are manifest in the retina during diabetes in humans and long-term animal models, since in addition to providing useful clues to the pathogenic basis of DR as a disease entity, it is in the deterrence of such changes that the efficacy of any novel treatment regimes will be measured. In particular, an emphasis will be placed on the relatively unappreciated role of arteriolar dysfunction in the clinical manifestations and pathology of this disease.
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Retinal ischaemic disorders such as diabetic retinopathy and retinal vein occlusion are common. The hypoxia-related stimuli from oxygen-deprived neural and glial networks can drive expression of growth factors and cytokines which induce leakage from the surviving vasculature and/or pre-retinal and papillary neovascularisation. If left untreated, retinal vascular stasis, hypoxia or ischaemia can lead to macular oedema or fibro-vascular scar formation which are associated with severe visual impairment, and even blindness. Current therapies for ischaemic retinopathies include laser photocoagulation, injection of corticosteroids or VEGF-antibodies and vitreoretinal surgery, however they carry significant side effects. As an alternative approach, we propose that if reparative intra-retinal angiogenesis can be harnessed at the appropriate stage, ischaemia could be contained or reversed. This review provides evidence that reperfusion of ischaemic retina and suppression of sight-threatening sequelae is possible in both experimental and clinical settings. In particular, there is emphasis on the clinical potential for endothelial progenitor cells (EPCs) to promote vascular repair and reversal of ischaemic injury in various tissues including retina. Gathering evidence from an extensive published literature, we outline the molecular and phenotypic nature of EPCs, how they are altered in disease and provide a rationale for harnessing the vascular reparative properties of various cell sub-types. When some of the remaining questions surrounding the clinical use of EPCs are addressed, they may provide an exciting new therapeutic option for treating ischaemic retinopathies. (C) 2011 Elsevier Ltd. All rights reserved.
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Ocular neovascularisation is a pathological hallmark of some forms of debilitating blindness including diabetic retinopathy, age related macular degeneration and retinopathy of prematurity. Current therapies for delaying unwanted ocular angiogenesis include laser surgery or molecular inhibition of the pro-angiogenic factor VEGF. However, targeting of angiogenic pathways other than, or in combination to VEGF, may lead to more effective and safer inhibitors of intraocular angiogenesis. In a small chemical screen using zebrafish, we identify LY294002 as an effective and selective inhibitor of both developmental and ectopic hyaloid angiogenesis in the eye. LY294002, a PI3 kinase inhibitor, exerts its anti-angiogenic effect in a dose-dependent manner, without perturbing existing vessels. Significantly, LY294002 delivered by intraocular injection, significantly inhibits ocular angiogenesis without systemic side-effects and without diminishing visual function. Thus, targeting of PI3 kinase pathways has the potential to effectively and safely treat neovascularisation in eye disease.
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Background: Age-related macular degeneration (AMD) is the leading cause of blindness in Western countries. Numerous risk factors have been reported but the evidence and strength of association is variable. We aimed to identify those risk factors with strong levels of evidence which could be easily assessed by physicians or ophthalmologists to implement preventive interventions or address current behaviours.
Resumo:
Age-related macular degeneration (AMD) is the most common cause of blindness in older people in developed countries, and risk for this condition may be classified as genetic or environmental, with an interaction between such factors predisposing to this disease. This study investigated the relationship between AMD risk genes, macular pigment optical density (MPOD), which may protect against AMD, and serum concentrations of the macular carotenoids, lutein (L) and zeaxanthin (Z). This was a cross-sectional study of 302 healthy adult subjects. Dietary intake of L and Z was assessed by food frequency questionnaire, and MPOD was measured by customized heterochromatic flicker photometry. We also calculated MPOD Area as the area of MP under the spatial profile curve, to reflect MP across the macula. Serum L and Z were measured by HPLC. Genotyping of tag SNPs in the genes CFH, ARMS2, C3, C2 and BF was undertaken with multiplex polymerase chain reaction (PCR) and primer extension methodology (ABI Snapshot, ABI Warrington UK) on DNA extracted from peripheral blood. The mean ± SD (range) age of the subjects in this study was 48 ± 11 (21-66) years. There was a statistically significant association between CFH genotype and family history of AMD, with subjects having two non-risk CFH haplotypes (n =35), or one non-risk and one protective CFH haplotype (n = 33), being significantly more likely to have a negative family history of AMD (Pearson Chi square: p = 0.001). There was no significant association between the AMD risk genes investigated and either MPOD (One way ANOVA: p > 0.05) or serum concentrations of L or Z (One way ANOVA: p > 0.05, for both). Subjects who were homozygous for risk alleles of both CFH and ARMS2 (n = 4) had significantly lower MPOD at 0.5_ and 1_ retinal eccentricity (Independent samples t test: p
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Studies of the female partners of politically motivated prisoners have generally studied women via a caring paradigm. Less well observed are those women who privately transgressed and challenged masculine-centred renditions or political imprisonment. This lacuna in the research dedicated to such women has been constructed around stereotypical depictions of them as a barely visible support network. We argue that the relatively indiscernible appearance of women who challenged such typecasting is attached to a persistent process of gender blindness within which women remain peripheral to wider narratives of collectivity and ideological presentation. We chart how some women actively involved themselves in creating their own identity as active agents, especially when the effects of conflict entered the private sphere.
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Neovascular retinal disease is a leading cause of blindness orchestrated by inflammatory responses. Although noninfectious uveoretinitis is mediated by CD4(+) T cells, in the persistent phase of disease, angiogenic responses are observed, along with degeneration of the retina. Full clinical manifestation relies on myeloid-derived cells, which are phenotypically distinct from, but potentially sharing common effector responses to age-related macular degeneration. To interrogate inflammation-mediated angiogenesis, we investigated experimental autoimmune uveoretinitis, an animal model for human uveitis. After the initial acute phase of severe inflammation, the retina sustains a persistent low-grade inflammation with tissue-infiltrating leukocytes for over 4 months. During this persistent phase, angiogenesis is observed as retinal neovascular membranes that arise from inflamed venules and postcapillary venules, increase in size as the disease progresses, and are associated with infiltrating arginase-1(+) macrophages. In the absence of thrombospondin-1, retinal neovascular membranes are markedly increased and are associated with arginase-1(-) CD68(+) macrophages, whereas deletion of the chemokine receptor CCR2 resulted in reduced retinal neovascular membranes in association with a predominant neutrophil infiltrate. CCR2 is important for macrophage recruitment to the retina in experimental autoimmune uveoretinitis and promotes chronicity in the form of a persistent angiogenesis response, which in turn is regulated by constitutive expression of angiogenic inhibitors like thrombospondin-1. This model offers a new platform to dissect the molecular and cellular pathology of inflammation-induced ocular angiogenesis.
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Purpose. Keratoconus is a progressive disorder of the cornea that can lead to severe visual impairment or blindness. Although several genomic regions have been linked to rare familial forms of keratoconus, no genes have yet been definitively identified for common forms of the disease. Methods. Two genome-wide association scans were undertaken in parallel. The first used pooled DNA from an Australian cohort, followed by typing of top-ranked single-nucleotide polymorphisms (SNPs) in individual DNA samples. The second was conducted in individually genotyped patients, and controls from the USA. Tag SNPs around the hepatocyte growth factor (HGF) gene were typed in three additional replication cohorts. Serum levels of HGF protein in normal individuals were assessed with ELISA and correlated with genotype. Results. The only SNP observed to be associated in both the pooled discovery and primary replication cohort was rs1014091, located upstream of the HGF gene. The nearby SNP rs3735520 was found to be associated in the individually typed discovery cohort (P = 6.1 × 10 ). Genotyping of tag SNPs around HGF revealed association at rs3735520 and rs17501108/rs1014091 in four of the five cohorts. Meta-analysis of all five datasets together yielded suggestive P values for rs3735520 (P = 9.9 × 10 ) and rs17501108 (P = 9.9 × 10 ). In addition, SNP rs3735520 was found to be associated with serum HGF level in normal individuals (P = 0.036). Conclusions. Taken together, these results implicate genetic variation at the HGF locus with keratoconus susceptibility. © 2011 The Association for Research in Vision and Ophthalmology, Inc.
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This edition of Milton’s Epistolarum Familiarium Liber Unus and of his Uncollected Letters, will appear as 672 pp. of The Complete Works of John Milton Volume XI, eds. Gordon Campbell and Edward Jones (Oxford University Press, forthcoming 2016). A diplomatic Latin text and a new facing English translation are complemented by a detailed Introduction and commentary that situate Milton’s Latin letters in relation to the classical, pedagogical and essentially humanist contexts at the heart of their composition. Now the art of epistolography advocated and exemplified by Cicero and Quintilian and embraced by Renaissance pedagogical manuals is read through a humanist filter whereby, via the precedent (and very title) of Epistolae Familiares, the Miltonic Liber is shown to engage with a neo-Latin re-invention of the classical epistola that had come to birth in quattrocento Italy in the letters of Petrarch and his contemporaries. At the same time the Epistolae are seen as offering fresh insight into Milton’s views on education, philology, his relations with Italian literati, his blindness, the poetic dimension of his Latin prose, and especially his verbal ingenuity as the ‘words’ of Latin ‘Letters’ become a self-conscious showcasing of etymological punning on the ‘letters’ of Latin ‘words’. The edition also announces several new discoveries, most notably its uncovering and collation of a manuscript of Henry Oldenburg’s transcription (in his Liber Epistolaris held in Royal Society, London) of Milton’s Ep. Fam. 25 (to Richard Jones). Oldenburg’s transcription (from the original sent to his pupil Jones) is an important find, given the loss of all but two of the manuscripts of Milton’s original Latin letters included in the 1674 volume. The edition also presents new evidence in regard to Milton’s relationships with the Italian philologist Benedetto Buonmattei, the Greek humanist Leonard Philaras, the radical pastor Jean Labadie (and the French church of London), and the elusive Peter Heimbach.
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Retinopathy is a major complication of diabetes mellitus and this condition remains a leading cause of blindness in the working population of developed countries. As diabetic retinopathy progresses a range of neuroglial and microvascular abnormalities develop although it remains unclear how these pathologies relate to each other and their net contribution to retinal damage. From a haemodynamic perspective, evidence suggests that there is an early reduction in retinal perfusion before the onset of diabetic retinopathy followed by a gradual increase in blood flow as the complication progresses. The functional reduction in retinal blood flow observed during early diabetic retinopathy may be additive or synergistic to pro-inflammatory changes, leucostasis and vaso-occlusion and thus be intimately linked to the progressive ischaemic hypoxia and increased blood flow associated with later stages of the disease. In the current review a unifying framework is presented that explains how arteriolar dysfunction and haemodynamic changes may contribute to late stage microvascular pathology and vision loss in human diabetic retinopathy.