[Pelvimetrics measures as predictives factors of positives surgical margins after robot-assisted laparoscopic prostatectomy]. / Mesures pelvimétriques prédictives de marges chirurgicales au décours d'une prostatectomie totale robot-assitée pour cancer prostatique.

INTRODUCTION: Anthropometric data report that pelvic bone of African subjects are narrower and the pelvic cavity is deeper. The aim of the study was to evaluate the influence of pelvic dimensions (PD) on Positive surgical margins (PSM) rate in Afro-Caribbean population after robot-assisted laparoscopic prostatectomy (RALP). PATIENTS AND METHODS: Preoperative pelvic MRI of all patients who have had RALP at the University Hospital Center of Guadeloupe between January 2013 and December 2015 was retrospectively analyzed. PD, including the Height of the upper edge of the prostate (HP), the Apical Depth (AD) and Ischial Spines Distance (ISD), and indexes (prostate volumetric index [ISD/VP], apical depth index [ISD/AD] and prostate depth index [ISD/(AD/HP)]) were compared according to the presence or absence of PSM with uni and multivariate analysis. RESULTS: One hundred and seventy-eight patients were included in the study, of whom 60 (33.7%) presented PSM. In univariate analysis, significant differences between the presence or absence of PSM were observed on the AD (30.3±8.7mm versus 24.8±8.0mm, P<0.001), the HP (9.5±8.5mm versus 16.8±11.9mm, P<0.001) and the ISD (89.6±8.8mm versus 96.1±8.4mm) as well as the indexes of apical depth and prostatic depth. In multivariate logistic regression, the ISD (P<0.001) and HP (P=0.02) were associated with increased likelihood of PSM, but not AD or indexes. CONCLUSION: This study suggests that interspinous distance is the best predictor of PSM during RALP in Afro-Caribbean patients. This measure may be useful to define the therapeutic pattern of patients with prostate cancer. A prospective study with a larger population, comparing RALP in Afro-Caribbean and in caucasians patients, would be needed.

High-resolution imaging of photoreceptors in healthy human eyes using an adaptive optics retinal camera.

PURPOSE: To determine the effects of age on perifoveal cone density in healthy subjects using adaptive optics. METHODS: Healthy subjects of various ages were imaged using an adaptive optics retinal camera (RTX-1® Imagine Eyes, Orsay, France). All patients underwent a comprehensive ophthalmologic examination and retinal imaging using spectral-domain optical coherence tomography (Spectralis®, Heidelberg Engineering, Heidelberg, Germany). Cone density together with cone spacing and cone mosaic packing were measured in the nasal and temporal area 450 µm from the fovea. A multivariate analysis was performed to determine which of the following parameters were related to a decrease in cone density: age, axial length, central macular thickness, and retrofoveal choroidal thickness. RESULTS: One hundred and sixty-seven eyes of 101 subjects aged 6-78 years were studied. Perifoveal cone density significantly decreased with age (R2 = 0.17, p<0.01). Inversely, cone spacing increased with age (R2=0.18, p<0.01). There was no change in the cone packing mosaic (p>0.05). The mean coefficient of variation between fellow eyes was 3.9%. Age and axial length were related to a cone density decrease, while choroidal and retinal thicknesses did not affect cone metrics in healthy subjects. CONCLUSIONS: A moderate perifoveal cone loss occurs with age. The precise consequences of these findings on visual function should be investigated. In addition to a better understanding of normal retinal anatomy, these results could act as a comparative database for further studies on normal and diseased retinas.

Effects of field contamination by metals (Cd, Cu, Pb, Zn) on biometry and mechanics of echinoderm ossicles.

Echinoderms are known to readily incorporate metals in their calcified endoskeleton. It is currently unclear if this has an impact on the skeleton function or if this can be considered as a detoxification mechanism. In the present work, populations of the sea urchin Echinus acutus and the starfish Asterias rubens were studied in stations distributed along a metal contamination gradient in a Norwegian fjord (Sørfjord). Ossicles involved in major mechanical functions - sea urchin spine and starfish ambulacral plate - were analyzed for their metal concentration (Cd, Cu, Pb and Zn) and their biometric and mechanical properties. Starfish plates were more contaminated by Cd, Pb and Zn than sea urchin spines. Cu concentrations were at background levels. In E. acutus, metals principally affected size. In A. rubens, material stiffness and toughness were decreased in the most contaminated station. This reduction is attributed either to the direct incorporation of metals in the calcite lattice and/or to deleterious effects of metals during skeleton ontogenesis. The contrasting incorporation of metals in the skeleton of the two investigated species accounts for the different impact of the metals, including in terms of fitness. The present results clearly indicate that, at least in A. rubens, incorporation of metals in the skeleton cannot be considered as a detoxification mechanism.

Structure, composition and mechanical relations to function in sea urchin spine.

Sea urchins have characteristic spines that fulfil critical functions. Several studies revealed marked spine internal heterogeneities at different structural levels despite the single-crystal character of the spines. Most of these studies did not speculate about the functional meaning of these heterogeneities. Spine heterogeneities were investigated in the sea urchin Paracentrotuslividus and their possible functional implications discussed. Spines mainly show two morphological parts: the base, made of a meshwork stereom, and the shaft, with longitudinal plain septa and a central core of meshwork stereom. Electron Backscatter Diffraction showed no difference in crystallite orientation between the two structures. Atomic Absorption Spectrometry and Energy dispersive X-ray analysis revealed that Mg was not uniformly distributed in the spine. Mg concentration is higher in the inner part of the septa than in the septum outer part. Furthermore, a cyclic pattern of Mg concentration in septa was observed. This is suggested to be linked to the spine ontogeny. Nano- and microindentation analyses revealed that the septa have higher stiffness and hardness than the meshwork stereom and that septum stiffness and hardness present different trends in longitudinal and transverse section. These mechanical heterogeneities may have an adaptive functional value.