Relationship Between Foveal Cone Structure and Visual Acuity Measured With Adaptive Optics Scanning Laser Ophthalmoscopy in Retinal Degeneration.

PurposeTo evaluate foveal function in patients with inherited retinal degenerations (IRD) by measuring visual acuity (VA) after correction of higher-order aberrations.MethodsAdaptive optics scanning laser ophthalmoscopy (AOSLO) was used to image cones in 4 healthy subjects and 15 patients with IRD. The 840-nm scanning laser delivered an "E" optotype to measure AOSLO-mediated VA (AOSLO-VA). Cone spacing was measured at the preferred retinal locus by two independent graders and the percentage of cones below the average density of 47 age-similar healthy subjects was computed. Cone spacing was correlated with best-corrected VA measured with the Early Treatment of Diabetic Retinopathy Study protocol (ETDRS-VA), AOSLO-VA, and foveal sensitivity.ResultsETDRS-VA significantly correlated with AOSLO-VA (ρ = 0.79, 95% confidence interval [CI] 0.5-0.9). Cone spacing correlated with AOSLO-VA (ρ = 0.54, 95% CI 0.02-0.7), and negatively correlated with ETDRS letters read (ρ = -0.64, 95% CI -0.8 to -0.2). AOSLO-VA remained ≥20/20 until cones decreased to 40.2% (CI 31.1-45.5) below normal. Similarly, ETDRS-VA remained ≥20/20 until cones were 42.0% (95% CI 36.5-46.1) below normal. Cone spacing z scores negatively correlated with foveal sensitivity (ρ = -0.79, 95% CI -0.9 to -0.4) and foveal sensitivity was ≥35 dB until cones were 43.1% (95% CI 39.3-46.6) below average.ConclusionsVA and foveal cone spacing were weakly correlated until cones were reduced by 40% to 43% below normal. The relationship suggests that VA is an insensitive measure of foveal cone survival; cone spacing may be a more sensitive measure of cone loss

De l’approche patrimoniale à la gestion durable des forêts : l’entrée « biodiversité » comme nouveau canon d’appréhension du réel

A travers l’analyse de la gestion contemporaine des forêts, cet article analyse la manière dont se transforme aujourd’hui le regard social sur les choses de la nature. Elles acquièrent progressivement le statut de choses fragiles, vulnérables que l’homme, compte tenu du principe de responsabilité qui lui échoit, doit comprendre et accompagner dans sa bienveillance pour leur durabilité. Ce registre émotionnel est mobilisé parallèlement à une rhétorique scientifique sur la diversité du vivant, la biodiversité, composée de multiples éléments en interactions formant un tout écosystémique qu’il convient d’envisager dans sa totalité pour respecter l’ensemble du vivant forestier, du microorganisme au vieil arbre bicentenaire. Nous montrerons comment ce nouveau système de valeurs s’institutionnalise à travers diverses actions de formation et d’éducation à l’environnement pour former une nouvelle normativité éthique, qui conduit à la divulgation des nouvelles « bonnes pratiques » sylvicoles

Loss of Foveal Cone Structure Precedes Loss of Visual Acuity in Patients With Rod-Cone Degeneration.

PurposeTo assess the relationship between cone spacing and visual acuity in eyes with rod-cone degeneration (RCD) followed longitudinally.MethodsHigh-resolution images of the retina were obtained using adaptive optics scanning laser ophthalmoscopy from 13 eyes of nine RCD patients and 13 eyes of eight healthy subjects at two sessions separated by 10 or more months (mean 765 days, range 311-1935 days). Cone spacing Z-score measured as close as possible (average <0.25°) to the preferred retinal locus was compared with visual acuity (letters read on the Early Treatment of Diabetic Retinopathy Study [ETDRS] chart and logMAR) and foveal sensitivity.ResultsCone spacing was significantly correlated with ETDRS letters read (ρ = -0.47, 95%CI -0.67 to -0.24), logMAR (ρ = 0.46, 95%CI 0.24 to 0.66), and foveal sensitivity (ρ = -0.30, 95%CI -0.52 to -0.018). There was a small but significant increase in mean cone spacing Z-score during follow-up of +0.97 (95%CI 0.57 to 1.4) in RCD patients, but not in healthy eyes, and there was no significant change in any measure of visual acuity.ConclusionsCone spacing was correlated with visual acuity and foveal sensitivity. In RCD patients, cone spacing increased during follow-up, while visual acuity did not change significantly. Cone spacing Z-score may be a more sensitive measure of cone loss at the fovea than visual acuity in patients with RCD

Cone Spacing Correlates With Retinal Thickness and Microperimetry in Patients With Inherited Retinal Degenerations.

PurposeTo determine whether high-resolution retinal imaging measures of macular structure correlate with visual function over 36 months in retinal degeneration (RD) patients and normal subjects.MethodsTwenty-six eyes of 16 RD patients and 16 eyes of 8 normal subjects were studied at baseline; 15 eyes (14 RD) and 11 eyes (6 normal) were studied 36 months later. Adaptive Optics Scanning Laser Ophthalmoscopy (AOSLO) was used to identify regions of interest (ROIs) with unambiguous cones at baseline to measure cone spacing. AOSLO images were aligned with spectral-domain optical coherence tomography (SD-OCT) and fundus-guided microperimetry results to correlate structure and function at the ROIs. SD-OCT images were segmented to measure inner segment (IS) and outer segment (OS) thickness. Correlations between cone spacing, IS and OS thickness and sensitivity were assessed using Spearman correlation coefficient ρ with bootstrap analyses clustered by person.ResultsCone spacing (ρ = 0.57, P < 0.001) and macular sensitivity (ρ = 0.19, P = 0.14) were significantly correlated with eccentricity in patients. Controlling for eccentricity, cone spacing Z-scores were inversely correlated with IS (ρ = -0.29, P = 0.002) and OS thickness (ρ = -0.39, P < 0.001) in RD patients only, and with sensitivity in normal subjects (ρ = -0.22, P < 0.001) and RD patients (ρ = -0.38, P < 0.001). After 36 months, cone spacing increased (P < 0.001) and macular sensitivity decreased (P = 0.007) compared to baseline in RD patients.ConclusionsCone spacing increased and macular sensitivity declined significantly in RD patients over 36 months. High resolution images of cone structure correlated with retinal sensitivity, and may be appropriate outcome measures for clinical trials in RD

Intoxications alimentaires à Salmonella du groupe E de la classification de Kauffmann

Névot Armand, Mégnin C., Pantaléon Jean, Jacque Raymond. Intoxications alimentaires à Salmonella du groupe E de la classification de Kauffmann. In: Bulletin de l'Académie Vétérinaire de France tome 101 n°7, 1948. pp. 292-296

On the Role of Dendritic Cells in Peripheral T Cell Tolerance and Modulation of Autoimmunity

Recently, it has become clear that dendritic cells (DCs) are essential for the priming of T cell responses. However, their role in the maintenance of peripheral T cell tolerance remains largely undefined. Herein, an antigen-presenting cell (APC) transfer system was devised and applied to experimental allergic encephalomyelitis (EAE), to evaluate the contribution that DCs play in peripheral T cell tolerance. The CD8α−CD4+ subset, a minor population among splenic DCs, was found to mediate both tolerance and bystander suppression against diverse T cell specificities. Aggregated (agg) Ig-myelin oligodendrocyte glycoprotein (MOG), an Ig chimera carrying the MOG 35–55 peptide, binds and cross-links FcγR on APC leading to efficient peptide presentation and interleukin (IL)-10 production. Furthermore, administration of agg Ig-MOG into diseased mice induces relief from clinical EAE involving multiple epitopes. Such recovery could not occur in FcγR-deficient mice where both uptake of Ig-MOG and IL-10 production are compromised. However, reconstitution of these mice with DC populations incorporating the CD8α−CD4+ subset restored Ig-MOG–mediated reversal of EAE. Transfer of CD8α+ or even CD8α−CD4− DCs had no effect on the disease. These findings strongly implicate DCs in peripheral tolerance and emphasize their functional potency, as a small population of DCs was able to support effective suppression of autoimmunity

Repeatability of Cone Spacing Measures in Eyes With Inherited Retinal Degenerations

PURPOSE. To determine short-term variability of adaptive optics scanning laser ophthalmoscopy (AOSLO)-derived cone spacing measures in eyes with inherited retinal degenerations (IRD) and in normal eyes. METHODS. Twenty IRD patients and 10 visually normal subjects underwent AOSLO imaging at two visits separated by no more than 1 month (NCT00254605). Cone spacing was measured in multiple macular regions in each image by three independent graders. Variability of cone spacing measures between visits, between graders, and between eyes was determined and correlated with standard clinical measures. RESULTS. Cone spacing was measured in 2905 regions. Interobserver agreement was high both in normal eyes and eyes with IRD (mean intraclass correlation coefficient [ICC] ¼ 0.838 for normal and 0.892 for eyes with IRD). Cone spacing measures were closely correlated between visits (ICC > 0.869 for both study groups). Mean relative intervisit spacing difference (absolute difference in measures divided by the mean at each region) was 4.0% for normal eyes and 4.9% for eyes with IRD. Cone spacing measures from fellow eyes of the same subject showed strong agreement for all subjects (ICC > 0.85 for both study groups). CONCLUSIONS. Adaptive optics scanning laser ophthalmoscopy-derived macular cone spacing measures were correlated between observers, visits, and fellow eyes of the same subject in normal eyes and in eyes with IRD. This information may help establish the role of cone spacing measures derived from images of the cone mosaic obtained with AOSLO as a sensitive biomarker for longitudinal tracking of photoreceptor loss during disease progression and in response to treatment. (ClinicalTrials.gov number, NCT00254605.