Immunohistochemical localization of collagen types I and VI in human skin wounds

A total of 74 human skin wounds were investigated and collagen types I and VI were localized in the wound area by immunohistochemistry. Collagen type I appeared in the form of ramifying string-like structures after approximately 5–6 days, but positive reactions in the form of a spot-like staining around isolated fibroblasts also occurred in a skin wound aged 4 days. Collagen VI was detectable after a post-infliction interval of at least 3 days showing a strongly positive reacting network associated with fibroblasts in the wound area. Both collagens appeared almost constantly after a wound age of 6–7 clays and could also be found in wounds aged a few months. Therefore, although a positive reaction for collagen type I in the form of string-like and ramifying structures around wound fibroblasts indicates a wound age of at least 5–6 days, a spot-like positive staining for collagen type I cannot exclude a wound age of at least 4 days. A positive staining for collagen type VI represents a post-infliction time of 3 days or more. The almost constant appearance of these collagen types suggests that negative results in a sufficient number of specimens indicate a wound age of less than 6–7 days, but cannot completely exclude longer post-infliction intervals. Since collagen type I and VI are also found in the granulation/scar tissue of lesions with advanced wound age, the immunohistochemical analysis of these proteins provides no further information for an age determination of older skin wounds

Obstetrical and neonatal characteristics vary with birthweight in a cohort of 100 term newborns with symptomatic arterial ischemic stroke

ObjectivesMany questions remain regarding the mechanism of perinatal stroke. Methods In a series of 100 prospectively enrolled term neonates with symptomatic arterial ischemic stroke, we explored family antecedents, pregnancy and delivery conditions and clinical presenting features and distinguished features of the 50 larger infants with the remainder. Cardiac and cervical arterial imaging were performed in 70 and 51 cases. Results Previous fetal loss, first pregnancy, primiparity, twin-gestation, cesarean and traumatic delivery, neonatal distress, male sex and premature rupture of membranes were statistically more common than in the general population. Normal pregnancy proportion and mean birthweight were in the normal range, arguing against a vasculo-placental origin in the majority. Furthermore, there was an excess of large babies. The larger infants were more subject to suffer from acute perinatal events, with a trend for an excess of neonatal distress (p = 0.065) and for more severe presenting features (p = 0.027), while the lighter were more likely to have experienced longstanding obstetrical risk factors such as complicated pregnancy (p = 0.047) and tobacco exposure (p = 0.028). Cervical MR angiography showed an internal carotid occlusion in two babies, whereas echo-Doppler was always normal; in one case the two methods were discordant. Echocardiography was non-informative. Interpretation The data from this prospective cohort of neonates with stroke confirm that many obstetrical and perinatal factors are risk determinants. They also suggest that birthweight and gender may be biomarkers of two populations of neonates with different pathological mechanisms. MR angiography appears more sensitive than echo-Doppler for the exploration of the neonatal cervical vasculature

Iterative framework for the joint segmentation and CT synthesis of MR images: application to MRI-only radiotherapy treatment planning.

To tackle the problem of magnetic resonance imaging (MRI)-only radiotherapy treatment planning (RTP), we propose a multi-atlas information propagation scheme that jointly segments organs and generates pseudo x-ray computed tomography (CT) data from structural MR images (T1-weighted and T2-weighted). As the performance of the method strongly depends on the quality of the atlas database composed of multiple sets of aligned MR, CT and segmented images, we also propose a robust way of registering atlas MR and CT images, which combines structure-guided registration, and CT and MR image synthesis. We first evaluated the proposed framework in terms of segmentation and CT synthesis accuracy on 15 subjects with prostate cancer. The segmentations obtained with the proposed method were compared using the Dice score coefficient (DSC) to the manual segmentations. Mean DSCs of 0.73, 0.90, 0.77 and 0.90 were obtained for the prostate, bladder, rectum and femur heads, respectively. The mean absolute error (MAE) and the mean error (ME) were computed between the reference CTs (non-rigidly aligned to the MRs) and the pseudo CTs generated with the proposed method. The MAE was on average [Formula: see text] HU and the ME [Formula: see text] HU. We then performed a dosimetric evaluation by re-calculating plans on the pseudo CTs and comparing them to the plans optimised on the reference CTs. We compared the cumulative dose volume histograms (DVH) obtained for the pseudo CTs to the DVH obtained for the reference CTs in the planning target volume (PTV) located in the prostate, and in the organs at risk at different DVH points. We obtained average differences of [Formula: see text] in the PTV for [Formula: see text], and between [Formula: see text] and 0.05% in the PTV, bladder, rectum and femur heads for D mean and [Formula: see text]. Overall, we demonstrate that the proposed framework is able to automatically generate accurate pseudo CT images and segmentations in the pelvic region, potentially bypassing the need for CT scan for accurate RTP

Etude de la diffraction de la détonation des mélanges C2H2-O2 stœchiométriques dilués par l'argon

Ce travail expérimental concerne l'étude des écoulements d'air au sein de canaux ondulés représentant les surfaces ailettées d'échangeurs de chaleurs compacts aéronautiques. L'objectif de cette étude est de comprendre et d'analyser les mécanismes dynamiques et thermiques qui se développent au sein de ces géométries complexes. Une attention toute particulière a été portée sur la caractérisation des phénomènes de transferts aux parois. Les résultats montrent l'influence de paramètres géométriques adimensionnels sur l'organisation de l'écoulement interne : facteur d'écartement, facteur d'ondulation et déphasage. L'écoulement est le siège du développement de couches limites caractérisées par des points de décollement et de recollement successifs. Ces phénomènes sont à l'origine de forts gradients des frottements pariétaux en bonne corrélation avec les variations tout aussi importantes des échanges de chaleur locaux. Des lois empiriques sont proposées pour des forts nombres de Reynolds. L'analyse fine des résultats permet de proposer une géométrie optimale. Ces travaux montrent aussi que l'écoulement moyen et fluctuant est établi au-delà de la 4ème période d'ondulation. Le développement des structures turbulentes et le niveau de turbulence sont indépendants du taux de turbulence initial, mais dépendent étroitement des dimensions géométriques du canal ondulé et du régime d'écoulement interne.This experimental approach concerns the study of the flows of air within wavy channels representing fin surfaces of aeronautics compact heat exchangers. The objective of this study is to understand and to analyse the dynamic and thermal mechanisms which develop within these complex geometries. A very particular attention was turned on the characterization of the phenomena of transfers in walls. Results show the influence of geometric no dimensional parameters on the organization of internal flow: factor of distance, factor of wave and phase. Flow is the seat of the development of boundary layers characterized by successive points of detachment and reattachment. These phenomena are at the origin of strong gradients of wall stress in good correlation with the also important variations of local heat exchanges. Empirical laws are offered for high Reynolds numbers. The fine analysis of results allows offering an optimum geometry. These works show that the mean and fluctuating flow is established beyond the 4th period of wave. The development of turbulent structures and the level of turbulence is independent of the initial rate of turbulence, but depend closely on geometric dimensions of the wavy channel and the regime of internal flow.POITIERS-BU Sciences (861942102) / SudocSudocFranceF

Caractérisation expérimentale et numérique de l'effet de diamètre de charge sur la détonation de mélanges explosifs homogènes et hétérogènes

Dans ce travail expérimental et numérique, nous avons mis au point des équations d état et des lois de libération d énergie permettant de décrire la propagation et l extinction de la détonation dans deux ensembles de composition explosives condensées homogènes ou hétérogènes. Les compositions homogènes étaient des mélanges de 2-Nitropropane et d Acide Nitrique et les compositions hétérogènes étaient constituées de Nitrométhane et de grains quasi-sphériques de Perchlorate d Ammonium de diamètre moyen 9, 35, 90, 200 et 400 m. Dans notre étude expérimentale, nous avons établi une base de données relative à l effet du diamètre de charge sur la célérité de détonation, y compris le diamètre critique de propagation, en fonction de la richesse des compositions et de la taille des grains des compositions hétérogènes, toutes monomodales. Dans notre étude numérique, nous avons étudié la propagation et l extinction de la détonation à l aide d une hypothèse de quasi monodimensionnalité de l écoulement pour estimer l effet de l expansion du confinement sur la zone de réaction. Nous avons modélisé le fluide réactif par une réunion de deux phases, l une non brûlée et l autre brûlée, supposées en équilibre thermique. Nous avons ainsi obtenu des paramètres pour nos lois de libération d énergie permettant de décrire nos résultats expérimentaux. Sous ces hypothèses, ces paramètres peuvent maintenant être utilisés pour simuler des phénomènes de détonation à plus grande échelle dans ces compositions.In this numerical and experimental work, we focus our attention on equation of state and heat release law which allow to describe propagation and extinction of detonation in two different kind of explosives compositions: homogeneous and heterogeneous. Homogeneous mixtures are composed of 2-Nitropropane and Nitric Acid and heterogeneous mixtures are composed of Nitromethane and bead Ammonium Perchlorate with mean diameter of 9, 35, 90, 200 and 400 m. In our experimental study, we have established a data base on charge diameter effect on detonation velocity, including critical diameter, in function of the equivalence ratio of the mixture and the size of particles for monomodal heterogeneous compositions. In our numerical work, we have studied detonation propagation and extinction under assumption of quasi-monodimensionnal flow to estimate the effect of the confinement expansion on the reaction zone. We have modelised the reactive flow by union of unburnt and burnt phases, in thermal equilibrium We have obtain parameters for heat release law which allow to describe our experimental results. Under these assumptions, those parameters could be used to stimulate detonation phenomena for this mixtures on large scale.POITIERS-BU Sciences (861942102) / SudocSudocFranceF

Intelligence Artificielle et nodules thyroïdiens : aide au TIRADS, indication de cytoponction. Étude prospective

International audienc

Neurological outcome and risk of recurrence depending on the anterior vs. posterior arterial distribution in children with stroke.

International audienceWe report the outcome of 46 previously healthy children with arterial ischemic stroke. After a mean follow-up of 26 months, five (11%) children suffered a recurrence and 28 (61%) were left with sequelae. The prevalence and the severity of the sequelae were similar irrespective of whether the localization of the accident was anterior or posterior. However, a recurrence was significantly more frequent in the posterior than in the anterior group (4/14 vs. 1/32; p=0.025). These observations may lead to the establishment of therapeutic guidelines according to the localization of the infarct

Impact of probe pressure variability on prostate localization for ultrasound-based image-guided radiotherapy

International audiencePurpose/Objective: For effective delivery of new radiotherapy techniques providing highly conformal dose distributions, the accurate positioning of the patient and the localization of the irradiated structures are crucial. For prostate cancer, a soft tissue imaging modality is required to setup the patient before irradiation sessions. The use of a three-dimensional transabdominal ultrasound system (3D-TA-US) could be a better alternative to X-ray based modalities because US based imaging is non-invasive,non-irradiating and allows for differentiation between soft tissues. Two issues related to an intramodality US imageguidance system for prostate cancers were investigated: 1. Impact of probe pressure on prostate localization, 2. Variability of the probe pressure during treatment sessions

Prospective multicentre observational study of lymphedema therapy: POLIT study

International audienceOBJECTIVE:Lymphedema treatment is based on Decongestive Lymphedema Therapy (DLT) with an intensive phase followed by a long-term maintenance phase. This study aimed to observe volume variation over the intensive phase and 6 months later.METHODS:Prospective multicentre observational study of patients with unilateral lymphedema. The primary objective was to assess lymphedema volume variation between baseline, the end of intensive phase and 6 months later. Secondary objectives were to assess the frequency of heaviness limiting limb function and treatments safety predictors for volume reduction.RESULTS:Three hundred and six patients (89.9% women; 59.9±14.3 years old) with upper/lower (n=184/122) limb lymphedema were included. At the end of the intensive phase, median excess lymphedema volume reduction was 31.0% (41.7-19.9) followed by a 16.5% (5.9-42.3) median increase over the 6-month maintenance period phase. Previous intensive treatment was the only significant predictor of this response. As compared to baseline, heaviness limiting limb use was much less frequently reported at the end of the reductive phase (75.5% versus 42.3% respectively), and was more frequent at the end of the maintenance phase (62.6%). The most frequent adverse events reported were skin redness and compression marks (18.4 and 15.7% of patients, respectively). Blisters requiring treatment stoppage were rare (1.4%).CONCLUSIONS:Intensive phase decreases lymphedema volume and heaviness limiting limb function. The benefit is partially abolished after the first 6 months of maintenance. There is a need to consider how to provide optimal patient care for the long-term control of lymphedema