Publications by authors named "HAMEL C"

We report an experimental implementation of long-range polarimetric imaging through fog over kilometric distance in real field atmospheric conditions. An incoherent polarized light source settled on a telecommunication tower is imaged at a distance of 1.3 km with a snapshot polarimetric camera including a birefringent Wollaston prism, allowing simultaneous acquisition of two images along orthogonal polarization directions.

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Purpose: Mutations in genes encoding proteins from the tri-snRNP complex of the spliceosome account for more than 12% of cases of autosomal dominant retinitis pigmentosa (adRP). Although the exact mechanism by which splicing factor defects trigger photoreceptor death is not completely clear, their role in retinitis pigmentosa has been demonstrated by several genetic and functional studies. To test for possible novel associations between splicing factors and adRP, we screened four tri-snRNP splicing factor genes (EFTUD2, PRPF4, NHP2L1, and AAR2) as candidate disease genes.

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Alterations of USH2A, encoding usherin, are responsible for more than 70% of cases of Usher syndrome type II (USH2), a recessive disorder that combines moderate to severe hearing loss and retinal degeneration. The longest USH2A transcript encodes usherin isoform b, a 5,202-amino-acid transmembrane protein with an exceptionally large extracellular domain consisting notably of a Laminin N-terminal domain and numerous Laminin EGF-like (LE) and Fibronectin type III (FN3) repeats. Mutations of USH2A are scattered throughout the gene and mostly private.

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Wolfram syndrome is an early onset genetic disease (1/180,000) featuring diabetes mellitus and optic neuropathy, associated to mutations in the WFS1 gene. Wfs1-/- mouse model shows pancreatic beta cell atrophy, but its visual performance has not been investigated, prompting us to study its visual function and histopathology of the retina and optic nerve. Electroretinogram and visual evoked potentials (VEPs) were performed in Wfs1-/- and Wfs1+/+ mice at 3, 6, 9 and 12 months of age.

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Autosomal dominant congenital stationary night blindness (adCSNB) is caused by mutations in three genes of the rod phototransduction cascade, rhodopsin (RHO), transducin α-subunit (GNAT1), and cGMP phosphodiesterase type 6 β-subunit (PDE6B). In most cases, the constitutive activation of the phototransduction cascade is a prerequisite to cause adCSNB. The unique adCSNB-associated PDE6B mutation found in the Rambusch pedigree, the substitution p.

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Background: Retinitis pigmentosa (RP) is the most frequent inherited retinal disease, which shows a relatively high incidence of the autosomal-recessive form in Pakistan.

Methods: Genome-wide high-density single-nucleotide polymorphism (SNP) microarrays were used to identify homozygous regions shared by affected individuals of one consanguineous family. DNA of three affected and two healthy siblings was used for SNP genotyping.

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Inherited retinal dystrophies are Mendelian neurodegenerative conditions classified as pigmentary retinopathies, macular dystrophies and others. Over a 21-year period, from 1990 to 2011, we have screened in Montpellier 107 genes in 609 families and have identified a causal mutation in 68.5% of them.

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Agroecosystems are dynamic systems that experience frequent chemical inputs and changes in plant cover. The objective of this study was to test whether abiotic (soil chemical properties and climate) and biotic (plant host identity) factors influence the spatial and temporal structuring of arbuscular mycorrhizal fungal (AMF) communities in a semi-arid prairie agroecosystem. 454 GS FLX+ high-throughput sequencing technology was successfully utilized to characterize the AMF communities based on long reads (mean length: 751.

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There is a 4-12% increase in mortality in the month following the start of Foundation Year 1 doctors (FY1s) in the UK. In 2012 the National Health Service announced a compulsory shadowing period for FY1s, aiming to increase familiarity with the environment in which the FY1 would be commencing work. There is no national curriculum of the content for this shadowing period and evidence suggests variable content of induction programmes across the UK.

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Inherited retinal dystrophies (IRDs) comprise a large group of genetically and clinically heterogeneous diseases that lead to progressive vision loss, for which a paucity of disease-mimicking animal models renders preclinical studies difficult. We sought to develop pertinent human cellular IRD models, beginning with choroideremia, caused by mutations in the CHM gene encoding Rab escort protein 1 (REP1). We reprogrammed REP1-deficient fibroblasts from a CHM (-/y) patient into induced pluripotent stem cells (iPSCs), which we differentiated into retinal pigment epithelium (RPE).

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Purpose: Autosomal recessive retinitis pigmentosa (arRP) is a genetically heterogeneous disease resulting in progressive loss of photoreceptors that leads to blindness. To date, 36 genes are known to cause arRP, rendering the molecular diagnosis a challenge. The aim of this study was to use homozygosity mapping to identify the causative mutation in a series of inbred families with arRP.

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Over one hundred VPS13B mutations are reported in Cohen syndrome (CS). Most cases exhibit a homogeneous phenotype that includes intellectual deficiency (ID), microcephaly, facial dysmorphism, slender extremities, truncal obesity, progressive chorioretinal dystrophy, and neutropenia. We report on a patient carrying two VPS13B splicing mutations with an atypical phenotype that included microcephaly, retinopathy, and congenital neutropenia, but neither obesity nor ID.

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This paper reports on the findings of a user trial of a mHealth application for pressure ulcer (bedsore) documentation. Pressure ulcers are a leading iatrogenic cause of death in developed countries and significantly impact quality of life for those affected. Pressure ulcers will be an increasing public health concern as the population ages.

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Objective: To compare long-term results of Lichtenstein's operation versus mesh plug repair for open inguinal hernia repair.

Background: The technique of best choice in open prosthetic inguinal hernia repair remains a subject of ongoing debate.

Methods: In this prospective, randomized controlled multicenter trial, patients with primary or recurrent inguinal hernias were randomized to undergo either Lichtenstein's operation or mesh plug repair.

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Mutations in CACNA1F encoding the α1-subunit of the retinal Cav1.4 L-type calcium channel have been linked to Cav1.4 channelopathies including incomplete congenital stationary night blindness type 2A (CSNB2), Åland Island eye disease (AIED) and cone-rod dystrophy type 3 (CORDX3).

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Inherited optic atrophy must be considered when working up any optic nerve involvement and any systemic disease with signs of optic atrophy, even with a negative family history. There are two classical forms: dominant optic atrophy, characterized by insidious, bilateral, slowly progressive visual loss and temporal disc pallor, and Leber's optic atrophy, characterized by acute loss of central vision followed by the same event in the fellow eye within a few weeks to months, with disc hyperemia in the acute phase. Family history is critical for diagnosis.

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Inherited retinal dystrophies are Mendelian neurodegenerative conditions. The mutations of the responsible genes lead both to cell dysfunction and cell death in the retina. The majority of these diseases are responsible for a progressive vision loss ending in almost complete blindness.

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The influence of land use on soil bio-resources is largely unknown. We examined the communities of arbuscular mycorrhizal (AM) fungi in wheat-growing cropland, natural areas, and seminatural areas along roads. We sampled the Canadian prairie extensively (317 sites) and sampled 20 sites in the Atlantic maritime ecozone for comparison.

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Vitelliform macular dystrophies (VMD) are inherited retinal dystrophies characterized by yellow, round deposits visible upon fundus examination and encountered in individuals with juvenile Best macular dystrophy (BMD) or adult-onset vitelliform macular dystrophy (AVMD). Although many BMD and some AVMD cases harbor mutations in BEST1 or PRPH2, the underlying genetic cause remains unknown for many affected individuals. In a large family with autosomal-dominant VMD, gene mapping and whole-exome sequencing led to the identification of a c.

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Importance: Retinitis punctata albescens (RPA) is an autosomal recessive form of retinitis pigmentosa characterized by white dotlike deposits in the fundus, in most cases caused by mutations in RLBP1.

Objective: To study disease progression and visual function in RPA.

Design: We performed clinical and molecular investigations in patients with RPA at various ages, from November 5, 2003, through June 20, 2012, with no planned patient follow-up.

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Purpose: To review what progress has been made towards the application of ocular gene therapy to prevent progressive vision loss in patients affected by choroideremia.

Design: A Perspective based on the collective opinions of researchers and clinicians actively engaged in vision research on choroideremia and a review of current literature.

Methods: Researchers from Europe, Canada, Australia, and the United States were convened to the first International Choroideremia Research Symposium held in Sommières, France in September 2011.

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The structure of postgraduate medical training rightly puts enormous emphasis on gathering clinical experience and constantly updating knowledge of relevant medical research to use in practice. At most, this can be contrasted with the slight emphasis on clinical leadership and acquiring the skills to effect change and improve the quality of care. Doctors play central roles in orchestrating the clinical management of patients across multiple settings within the healthcare system.

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