Evaluation qualitative macroscopique et microscopique du grasset chez un modèle expérimental d'arthrose canine 90 jours après section du ligament croisé crânial

La transection du ligament croisé crânial (CCLT) est une méthode couramment admise d'induction expérimentale d'arthrose (OA) au niveau du grasset chez le chien. Le but principal de cette étude était d'évaluer qualitativement les lésions d'arthrose induites par la CCLT par macroscopie et histologie 90 jours après chez 21 jeunes femelles de race beagle. Les lèvres de la trochlée fémorale présentaient le plus haut score ostéophytique tandis que la patelle présentait le plus bas et celui du condyle fémoral médial était supérieur à celui du condyle latéral. Les lésions méniscales ont été observées uniquement sur le ménisque médial de 5 genoux opérés. Les lésions macroscopiques du cartilage (stade de fibrillation) ont été notées dans un ordre de fréquence décroissant sur les condyles tibiaux médial et latéral, le condyle fémoral latéral, la trochlée fémorale, le condyle fémoral médial et enfin la patelle. L'examen histologique a révélé que la couche superficielle du cartilage était fibrillée et discontinue. La plupart des cellules étaient rondes et disposées tangentiellement à la surface. Dans les zones transitionnelle et profonde, quelques chondrocytes étaient modérément hypertrophiques et des amas de chondrocytes ont été uniquement observés dans la couche profonde. Concernant la membrane synoviale, un épaississement du mésothélium et une importante densité de collagène ont été notés et le rapport des épaisseurs mésothélium/fibres était entre 1/0.15 et 1/0.10 sur les genoux opérés et 1/0.05 sur les genoux témoins. Les images fournies ici pourront servir de références pour des travaux ultérieurs portant notamment sur les thérapies contre l'arthrose

Radiographic assessment of the femorotibial joint of the CCLT rabbit experimental model of osteoarthritis

<p>Abstract</p> <p>Background</p> <p>The purposes of the study were to determine the relevance and validity of in vivo non-invasive radiographic assessment of the CCLT (Cranial Cruciate Ligament Transection) rabbit model of osteoarthritis (OA) and to estimate the pertinence, reliability and reproducibility of a radiographic OA (ROA) grading scale and associated radiographic atlas.</p> <p>Methods</p> <p>In vivo non-invasive extended non weight-bearing radiography of the rabbit femorotibial joint was standardized. Two hundred and fifty radiographs from control and CCLT rabbits up to five months after surgery were reviewed by three readers. They subsequently constructed an original semi-quantitative grading scale as well as an illustrative atlas of individual ROA feature for the medial compartment. To measure agreements, five readers independently scored the same radiographic sample using this atlas and three of them performed a second reading. To evaluate the pertinence of the ROA grading scale, ROA results were compared with gross examination in forty operated and ten control rabbits.</p> <p>Results</p> <p>Radiographic osteophytes of medial femoral condyles and medial tibial condyles were scored on a four point scale and dichotomously for osteophytes of medial fabella. Medial joint space width was scored as normal, reduced or absent. Each ROA features was well correlated with gross examination (p < 0.001). ICCs of each ROA features demonstrated excellent agreement between readers and within reading. Global ROA score gave the highest ICCs value for between (ICC 0.93; CI 0.90-0.96) and within (ICC ranged from 0.94 to 0.96) observer agreements. Among all individual ROA features, medial joint space width scoring gave the highest overall reliability and reproducibility and was correlated with both meniscal and cartilage macroscopic lesions (r_s= 0.68 and r_s= 0.58, p < 0.001 respectively). Radiographic osteophytes of the medial femoral condyle gave the lowest agreements while being well correlated with the macroscopic osteophytes (r_s= 0.64, p < 0.001).</p> <p>Conclusion</p> <p>Non-invasive in vivo radiography of the rabbit femorotibial joint is feasible, relevant and allows a reproducible grading of experimentally induced OA lesion. The radiographic grading scale and atlas presented could be used as a template for in vivo non invasive grading of ROA in preclinical studies and could allow future comparisons between studies.</p

Découverte et résultats d’analyse de statuaire médiévale et moderne de la cathédrale de Rodez (Aveyron).

During recent works of electrification in the nave of the Gothic cathedral of Rodez (1277-by 1580) and the installation of a duct under the floor of a chapel, the discovery of sculptured fragments buried under the pavement was reported. A first archaeological rescue operation conducted in 1998 allowed the discovery of 160 such fragments. In April 2006, a more ambitious programmed excavation has in turn resulted in the extraction of more than 250 fragments. It was followed by an inventory work and an archaeological, historical, stylistic and iconographic study the results of which are presented here.Lors de récents travaux d’électrification de la nef de la cathédrale gothique de Rodez (1277 -vers 1580) et de la pose d’une gaine dans le sol d’une chapelle, des fragments sculptés ont été signalés, enfouis sous le dallage. Une première opération archéologique de sauvetage a été effectuée en 1998 et a permis la mise au jour et l’inventaire de 160 fragments. En avril 2006, une opération de fouille programmée d’une plus grande ampleur a quant à elle abouti à l’extraction de plus de 2500 fragments. Cela a donné suite à un travail d’inventaire et à une étude archéologique, historique, stylistique et iconographique dont les résultats sont ici présentés.De Barrau-Agudo Caroline, Fau Laurent. Découverte et résultats d’analyse de statuaire médiévale et moderne de la cathédrale de Rodez (Aveyron).. In: Archéologie du Midi médiéval. Tome 27, 2009. pp. 97-136

Recent advances in homomorphic encryption: a possible future for signal processing in the encrypted domain

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Towards practical program execution over fully homomorphic encryption schemes

International audienceThis paper intends to provide a first assessment of the practicality of using Fully Homomorphic Encryption (FHE) to perform real calculations, in terms of software engineering as well as performances. We present a prototype of a compilation and execution infrastructure targeting any FHE scheme. The paper also provides some preliminary experimental results obtained with our implementation of the Brakerski-Gentry-Vaikuntanathan (BGV) scheme, which is one of the most promising FHE scheme with respect to practicality.

Soft Tissue and Marginal Bone Adaptation on Platform-Switched Implants with a Morse Cone Connection: A Histomorphometric Study in Dogs

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Early Periimplant Tissue Healing on 1-Piece Implants With a Concave Transmucosal Design

International audienceIntroduction: The purpose of our study was to investigate the early healing phase of marginal bone and soft tissues around unloaded 1-piece implants with a concave transmucosal design, in a dog model.Methods: Twenty-four 1-piece implants with a concave transmucosal neck were inserted 1 mm subcrestally in the mandibular ridge of 8 beagle dogs. Four animals were sacrificed after 3 and 12 weeks of healing. Histomorphometric analysis was performed to measure the height of the periimplant tissues.Results and Discussion: The overall height of the periimplant mucosa was, respectively, 2.67 and 2.52 mm, after 3 and 12 weeks. In the connective tissue, a soft tissue O-ring seal was observed in the healing area provided by the transmucosal concavity, after 12 weeks. The location of the first bone-to-implant contact facing the implant shoulder was 0.00 and +0.18 mm, respectively, after 3 and 12 weeks of healing. Some bone apposition occurred on the implant shoulder during the healing.Conclusion: Within the limits of the present study, a concave transmucosal design in 1-piece implants was associated with a short vertical value of biological width and promoted a mechanical interlocking of the implant body at the connective tissue and marginal bone levels

Influence of Different Implant Types on Bone Levels After Healing and Peri-implant Tissue Reactions Following Peri-implantitis: A Preclinical Study

International audienceThis study evaluated the influence of different implant types on (1) radiographic marginal bone levels after healing and (2) radiographic and histomorphometric tissue levels and characteristics following ligature-induced peri-implantitis. Four implant types (Standard Plus, Straumann [S]; NobelReplace Tapered, Nobel Biocare [N]; In-Kone Universal, Global D [I]; and twinKon, Global D [T]) were randomly placed in the edentulous healed mandibular ridge of six dogs (T0), for a total of 57 implants placed. After 10 weeks, a peri-implantitis was ligature-induced (T1). After 12 weeks, biopsy samples were processed for histomorphometric analysis (T2). Standardized radiographs were taken at T0, T1, and T2 for imaging analysis. Statistical analysis was performed using mixed-effects linear modeling. After healing (T1), the radiographic marginal bone level was more coronal for implants I, T, and S compared to N. Following peri-implantitis (T2), the histologic marginal bone level was more coronal for implants I, T, and S compared to N, and for implants I and T compared to S. Also at T2, the radiographic marginal bone level was more coronal at implants I, T, and S compared to N. Implant type may influence bone remodeling during healing and bone loss during the early stages of experimental peri-implantitis

SingleCellSignalR: inference of intercellular networks from single-cell transcriptomics

International audienceAbstract Single-cell transcriptomics offers unprecedented opportunities to infer the ligand–receptor (LR) interactions underlying cellular networks. We introduce a new, curated LR database and a novel regularized score to perform such inferences. For the first time, we try to assess the confidence in predicted LR interactions and show that our regularized score outperforms other scoring schemes while controlling false positives. SingleCellSignalR is implemented as an open-access R package accessible to entry-level users and available from https://github.com/SCA-IRCM. Analysis results come in a variety of tabular and graphical formats. For instance, we provide a unique network view integrating all the intercellular interactions, and a function relating receptors to expressed intracellular pathways. A detailed comparison of related tools is conducted. Among various examples, we demonstrate SingleCellSignalR on mouse epidermis data and discover an oriented communication structure from external to basal layers

Impregnation of High-Magnetization FeCo Nanoparticles in Mesoporous Silicon: An Experimental Approach

International audienceThis paper deals with the synthesis of high-magnetization porous silicon-based nanocomposites. Using well-controlled organometallic synthesis of ferromagnetic FeCo nanoparticles, the impregnation of mesoporous silicon has been performed by immersion of porous silicon in a colloidal solution. The technique was optimized by controlling the temperature, the immersion duration, and the solvent nature. The characterization of the nanocomposites showed a homogeneous filling of the pores and a high magnetization of 135 emu/cm3. Such composites present a great interest for many applications including data storage, medical instrumentations, catalysis, or electronics