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Le Touquet – Paris-Plage, France

Plaisier E.,AP HP | Plaisier E.,French Institute of Health and Medical Research | Plaisier E.,University Pierre and Marie Curie | Chen Z.,French Institute of Health and Medical Research | And 10 more authors.
American Journal of Medical Genetics, Part A | Year: 2010

The COL4A1 gene encodes the α1-chain of type IV collagen, which is ubiquitously expressed in basement membranes. Mutations in COL4A1 have been reported in autosomal-dominant porencephaly and in patients with symptomatic small vessel brain disease, inconstantly associated with eye defects. We have previously reported three COL4A1 mutations associated with a systemic phenotype that we called HANAC (Hereditary Angiopathy, Nephropathy, Aneurysms, and Cramps). We carried out a clinical and genetic study of three families presenting with characteristic features of HANAC syndrome. Common systemic signs included arterial retinal tortuosity and muscle cramps, with a variable combination of small vessel brain disease, Raynaud phenomena, and kidney defects. Three novel COL4A1 missense substitutions are described, which affect highly conserved glycine residues within the collagenous domain of the protein. All six known mutations associated with the HANAC phenotype are localized within the CB3[IV] fragment of COL4A1, which encompasses major integrin-binding sites. Our results confirm that HANAC syndrome is a distinct clinical entity within the COL4A1-related disorders, which is characterized by systemic involvement and usually asymptomatic brain disease. The restricted distribution of COL4A1 mutations within the CB3[IV] region is a characteristic of the reports of patients with HANAC, which suggests that abnormal cell-type IV collagen interactions may underlie the systemic defects observed in this syndrome. © 2010 Wiley-Liss, Inc. Source


Ghorbel I.,FOVEA Pharmaceuticals | Ghorbel I.,Telecom ParisTech | Rossant F.,ISEP | Bloch I.,Telecom ParisTech | Paques M.,Clinical Investigation Center 503
Proceedings - International Conference on Image Processing, ICIP | Year: 2011

Parametric deformable models are an important technique for image segmentation. In order to improve the robustness of the model, it may be interesting to incorporate a priori information about the shape of the objects to be segmented. In this paper, we propose to add a parallelism constraint. Such a model is relevant in many applications where elongated structures have to be detected. One main advantage of our formulation is that it only needs few parameters to be adjusted in addition to those of traditional snakes. The proposed model has been applied for the segmentation of OCT images of the retina and for the segmentation of retinal vessels. Experimental results, obtained on 25 OCT images and 30 eye fundus images, demonstrated the robustness, flexibility and large potential applicability of this new formulation. The accuracy of the method has been assessed by comparing manual segmentations, made by experts, with the automatic ones. © 2011 IEEE. Source


Koch E.,Clinical Investigation Center 503 | Rosenbaum D.,Institute of cardiometabolism and nutrition | Brolly A.,Clinical Investigation Center 503 | Sahel J.-A.,Clinical Investigation Center 503 | And 5 more authors.
Journal of Hypertension | Year: 2014

OBJECTIVES:: The wall-to-lumen ratio (WLR) of retinal arteries is a recognized surrogate of end-organ damage due to aging and/or arterial hypertension. However, parietal morphometry remains difficult to assess in vivo. Recently, it was shown that adaptive optics retinal imaging can resolve parietal structures of retinal arterioles in humans in vivo. Here, using adaptive optics retinal imaging, we investigated the variations of parietal thickness of small retinal arteries with blood pressure and focal vascular damage. METHODS:: Adaptive optics imaging of the superotemporal retinal artery was done in 49 treatment-naive individuals [mean age (±SD) 44.9 years (±14); mean systolic pressure 132 mmHg (±22)]. Semi-automated segmentation allowed extracting parietal thickness and lumen diameter. In a distinct cohort, adaptive optics images of arteriovenous nicking (AVN; n=12) and focal arteriolar narrowing (FAN; n=10) were also analyzed qualitatively and quantitatively. RESULTS:: In the cohort of treatment-naive individuals, by multiple regression taking into account age, body mass index, mean, systolic, diastolic and pulse blood pressure, the WLR was found positively correlated to mean blood pressure and age which in combination accounted for 43% of the variability of WLR. In the cohort of patients with focal vascular damage, neither FANs or AVNs showed evidence of parietal growth; instead, at sites of FANs, decreased outer diameter suggestive of vasoconstriction was consistently found, while at sites of AVNs venous narrowing could be seen in the absence of arteriovenous contact. CONCLUSION:: High resolution imaging of retinal vessels by adaptive optics allows quantitative microvascular phenotyping, which may contribute to a better understanding and management of hypertensive retinopathy. Copyright © Lippincott Williams & Wilkins. Source


Trinh L.,Quinze Vingts National Ophthalmology Hospital | Trinh L.,Clinical Investigation Center 503 | Francoz M.,Quinze Vingts National Ophthalmology Hospital | Francoz M.,Clinical Investigation Center 503 | And 10 more authors.
Journal Francais d'Ophtalmologie | Year: 2013

Purpose To evaluate anatomic appearance and corneal cellular modifications after monocular Intracor® procedure with two different anterior segment imaging techniques within the first postoperative year. Patients and methods Four patients underwent an Intracor® procedure in one eye performed at Clinique de la vision, and corneal imaging was performed in Quinze-Vingts National Ophthalmology Hospital. Slit-lamp photography, confocal microscopy with Heidelberg retinal tomography (HRT) and anterior segment spectral-domain optical coherence tomography (OCT) were performed 2 days, and 1, 6, and 12 months after the procedure. Results Confocal microscopy showed strong cellular activation of keratocytes within the first postoperative month which diminished over time. The linear femtosecond incisions appeared as hyper-reflective regular lines and reflectivity decreased throughout the follow-up period. After 6 months, a fibrotic process with appearance of corneal scars was visible as small intrastromal hyper-reflective lines and thick hyper-reflective spicules around the incisions and remained stable over time. On spectral-domain OCT, the size and depth of the incisions decreased from the center to the periphery. Visibility of the corneal femtosecond incisions on OCT decreased from day 2 until they almost disappeared at 12 months. The incision angles seemed to curve progressively from the center to the periphery in their deep portion on the peripheral rings. Conclusion Corneal cellular modifications found on HRT, anatomical features, and the sizes of the intrastromal rings, may provide valuable information on this new refractive technique. © 2013 Elsevier Masson SAS. Source


Trinh L.,Quinze Vingts National Ophthalmology Hospital | Saubamea B.,French Institute of Health and Medical Research | Saubamea B.,University of Paris Descartes | Auclin F.,Quinze Vingts National Ophthalmology Hospital | And 16 more authors.
Journal Francais d'Ophtalmologie | Year: 2014

SummaryPurpose To describe a new technique of endothelial keratoplasty (EK) that improves the quality of lamellar dissection of donor cornea. Methods We compared four techniques of donor cornea preparation for lamellar dissection on 8 donor corneas: mechanical dissection with a microkeratome, a single femtosecond laser lamellar cut, a double femtosecond laser lamellar cut and combined femtosecond laser lamellar dissection with excimer laser surface photoablation. The quality of the donor cornea interface was assessed and compared using scanning electron microscopy (SEM), and the most satisfactory technique was employed for EK on three patients. The postoperative anatomic results were analyzed with anterior segment spectral-domain optical coherence tomography (SD-OCT) and in vivo confocal microscopy (IVCM). Results The smoothest stromal interface was observed on SEM with the combined use of femtosecond laser dissection and excimer photoablation. The surgical procedures performed with donor cornea prepared by a combination of femtosecond and excimer lasers resulted in clear corneas after 1 month. SD-OCT showed good attachment of the endothelial graft and a hyperreflective interface. On IVCM, subepithelial haze, honeycomb-like activated keratocytes and needle-shaped particles were visible in the recipient corneal stroma as well as numerous hyperreflective particles on the donor-recipient interface. Conclusion A new technique, femtosecond and excimer laser-assisted endothelial keratoplasty (FELEK), which refines the current limitations observed in Descemet-stripping automated endothelial keratoplasty (DSAEK), is described. Femtosecond laser dissection provides a thin and reproducible endothelial graft cut with a high level of safety and accuracy, while excimer photoablation yields a smooth, high-quality interface. © 2014 Elsevier Masson SAS. All rights reserved. Source

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