Image Quality Comparison of Three 3D Mobile X-Ray Imaging Guidance Devices Used in Spine Surgery: A Phantom Study.

An image-quality CT phantom was scanned with three different 3D X-ray imaging guidance devices in the operating theatre: O-Arm, Loop-X, and Airo TruCT. Default acquisition and reconstruction parameters for lumbar spine procedures were used on each device. The tube current was set to a dose level of around 27 mGy.

Artificial Intelligence for Detecting Acute Fractures in Patients Admitted to an Emergency Department: Real-Life Performance of Three Commercial Algorithms.

Rationale And Objectives: Interpreting radiographs in emergency settings is stressful and a burden for radiologists. The main objective was to assess the performance of three commercially available artificial intelligence (AI) algorithms for detecting acute peripheral fractures on radiographs in daily emergency practice.

Materials And Methods: Radiographs were collected from consecutive patients admitted for skeletal trauma at our emergency department over a period of 2 months.

Application of artificial intelligence to imaging interpretations in the musculoskeletal area: Where are we? Where are we going?

The interest of researchers, clinicians and radiologists, in artificial intelligence (AI) continues to grow. Deep learning is a subset of machine learning, in which the computer algorithm itself can determine the optimal imaging features to answer a clinical question. Convolutional neural networks are the most common architecture for performing deep learning on medical images.

Patient dose in interventional radiology: a multicentre study of the most frequent procedures in France.

Objectives: A national retrospective survey on patient doses was performed by the French Society of Medical physicists to assess reference levels (RLs) in interventional radiology as required by the European Directive 2013/59/Euratom.

Methods: Fifteen interventional procedures in neuroradiology, vascular radiology and osteoarticular procedures were analysed. Kerma area product (KAP), fluoroscopy time (FT), reference air kerma and number of images were recorded for 10 to 30 patients per procedure.

Establishment of diagnostic reference levels in cardiac CT in France: a need for patient dose optimisation.

The objective of this study was to propose diagnostic reference levels (DRLs) for coronary computed tomography angiography (CCTA), in the context of a large variability in patient radiation dose, and the lack of European recommendations. Volume Computed Tomography Dose Index (CTDIvol) and dose-length product (DLP) were collected from 460 CCTAs performed over a 3-month period at eight French hospitals. CCTAs (∼50 per centre) were performed using the routine protocols of the centres, and 64- to 320-detector CT scanners.

Medical physics personnel for medical imaging: requirements, conditions of involvement and staffing levels-French recommendations.

The French regulations concerning the involvement of medical physicists in medical imaging procedures are relatively vague. In May 2013, the ASN and the SFPM issued recommendations regarding Medical Physics Personnel for Medical Imaging: Requirements, Conditions of Involvement and Staffing Levels. In these recommendations, the various areas of activity of medical physicists in radiology and nuclear medicine have been identified and described, and the time required to perform each task has been evaluated.

Identification of soluble 14-3-3∊ as a novel subchondral bone mediator involved in cartilage degradation in osteoarthritis.

Objective: Mechanical stress plays an important role in cartilage degradation and subchondral bone remodeling in osteoarthritis (OA). The remodeling of the subchondral bone could initiate cartilage loss in OA through the interplay of bone and cartilage. The aim of this study was to identify soluble mediators released by loaded osteoblasts/osteocytes that could induce the release of catabolic factors by chondrocytes.

Stress-induced cartilage degradation does not depend on the NLRP3 inflammasome in human osteoarthritis and mouse models.

Objective: The main feature of osteoarthritis (OA) is degradation and loss of articular cartilage. Interleukin-1β (IL-1β) is thought to have a prominent role in shifting the metabolic balance toward degradation. IL-1β is first synthesized as an inactive precursor that is cleaved to the secreted active form mainly in the "inflammasome," a complex of initiators (including NLRP3), adaptor molecule ASC, and caspase 1.

Proinflammatory actions of visfatin/nicotinamide phosphoribosyltransferase (Nampt) involve regulation of insulin signaling pathway and Nampt enzymatic activity.

Visfatin (also termed pre-B-cell colony-enhancing factor (PBEF) or nicotinamide phosphoribosyltransferase (Nampt)) is a pleiotropic mediator acting on many inflammatory processes including osteoarthritis. Visfatin exhibits both an intracellular enzymatic activity (nicotinamide phosphoribosyltransferase, Nampt) leading to NAD synthesis and a cytokine function via the binding to its hypothetical receptor. We recently reported the role of visfatin in prostaglandin E(2) (PGE(2)) synthesis in chondrocytes.

Induction of the chemokine IL-8/Kc by the articular cartilage: possible influence on osteoarthritis.

Purpose: IL-8 and its murine equivalent keratinocyte chemoattractant (Kc), chemokines produced by chondrocytes, contribute to the pathophysiology of osteoarthritis. However, the mechanisms leading to their production are poorly known. We aimed to investigate whether mechanical (compression), inflammatory (IL-1β) and metabolic (visfatin) stresses may induce the release of Kc when applied on murine cartilage.

Inhibition of matrix metalloproteinase-3 and -13 synthesis induced by IL-1beta in chondrocytes from mice lacking microsomal prostaglandin E synthase-1.

Joint destruction in arthritis is in part due to the induction of matrix metalloproteinase (MMP) expression and their inhibitors, especially MMP-13 and -3, which directly degrade the cartilage matrix. Although IL-1β is considered as the main catabolic factor involved in MMP-13 and -3 expression, the role of PGE(2) remains controversial. The goal of this study was to determine the role of PGE(2) on MMP synthesis in articular chondrocytes using mice lacking microsomal PGE synthase-1 (mPGES-1), which catalyses the rate-limiting step of PGE(2) synthesis.

Mesenchymal stem cell therapy regenerates the native bone-tendon junction after surgical repair in a degenerative rat model.

Background: The enthesis, which attaches the tendon to the bone, naturally disappears with aging, thus limiting joint mobility. Surgery is frequently needed but the clinical outcome is often poor due to the decreased natural healing capacity of the elderly. This study explored the benefits of a treatment based on injecting chondrocyte and mesenchymal stem cells (MSC) in a new rat model of degenerative enthesis repair.

Chemical inducers and transcriptional markers of oligodendrocyte differentiation.

Oligodendrocytes generate and maintain myelin, which is essential for axonal function and protection of the mammalian central nervous system. To advance our molecular understanding of differentiation by these cells, we screened libraries of pharmacologically active compounds and identified inducers of differentiation of Oli-neu, a stable cell line of mouse oligodendrocyte precursors (OPCs). We identified four broad classes of inducers, namely, forskolin/cAMP (protein kinase A activators), steroids (glucocorticoids and retinoic acid), ErbB2 inhibitors, and nucleoside analogs, and confirmed the activity of these compounds on rat primary oligodendrocyte precursors and mixed cortical cultures.

Stigmasterol: a phytosterol with potential anti-osteoarthritic properties.

Objective: Although most studies have focused on the cholesterol-lowering activity of stigmasterol, other bioactivities have been ascribed to this plant sterol compound, one of which is a potential anti-inflammatory effect. To investigate the effects of stigmasterol, a plant sterol, on the inflammatory mediators and metalloproteinases produced by chondrocytes.

Method: We used a model of newborn mouse chondrocytes and human osteoarthritis (OA) chondrocytes in primary culture stimulated with or without IL-1beta (10 ng/ml), for 18 h.

Functional whole-genome analysis identifies Polo-like kinase 2 and poliovirus receptor as essential for neuronal differentiation upstream of the negative regulator alphaB-crystallin.

This study aimed at identifying transcriptional changes associated to neuronal differentiation induced by six distinct stimuli using whole-genome microarray hybridization analysis. Bioinformatics analyses revealed the clustering of these six stimuli into two categories, suggesting separate gene/pathway dependence. Treatment with specific inhibitors demonstrated the requirement of both Janus kinase and microtubule-associated protein kinase activation to trigger differentiation with nerve growth factor (NGF) and dibutyryl cAMP.

Involvement of the Notch pathway in the regulation of matrix metalloproteinase 13 and the dedifferentiation of articular chondrocytes in murine cartilage.

Objective: To demonstrate the activation of the Notch signaling pathway during changes in the phenotype of chondrocytes in vitro, and to assess the influence of Notch on the production of chondrocyte markers.

Methods: Serial monolayer primary cultures of murine articular chondrocytes (MACs), as a model of chondrocyte dedifferentiation, were prepared. MACs were cultured with or without a Notch inhibitor and transfected with different Notch-expressing vectors.

Convergent functional genomics of oligodendrocyte differentiation identifies multiple autoinhibitory signaling circuits.

Inadequate remyelination of brain white matter lesions has been associated with a failure of oligodendrocyte precursors to differentiate into mature, myelin-producing cells. In order to better understand which genes play a critical role in oligodendrocyte differentiation, we performed time-dependent, genome-wide gene expression studies of mouse Oli-neu cells as they differentiate into process-forming and myelin basic protein-producing cells, following treatment with three different agents. Our data indicate that different inducers activate distinct pathways that ultimately converge into the completely differentiated state, where regulated gene sets overlap maximally.

Mechanical loading highly increases IL-6 production and decreases OPG expression by osteoblasts.

Objectives: In osteoarthritis (OA), mechanical factors play a key role, not only in cartilage degradation, but also in subchondral bone sclerosis. The aim of this study was to develop on original compression model for studying the effect of mechanical stress on osteoblasts.

Materials And Methods: We investigate the effects of compression on primary calvaria osteoblasts isolated from newborn mice and cultured for 28 days in monolayer.

Crucial role of visfatin/pre-B cell colony-enhancing factor in matrix degradation and prostaglandin E2 synthesis in chondrocytes: possible influence on osteoarthritis.

Objective: Prostaglandin E2 (PGE2) is one of the main catabolic factors involved in osteoarthritis (OA), and metalloproteinases (MMPs) are crucial for cartilage degradation. PGE2 synthesis under inflammatory conditions is catalyzed by cyclooxygenase 2 and microsomal PGE synthase 1 (mPGES-1), whereas NAD+-dependent 15-hydroxy-PG dehydrogenase (15-PGDH) is the key enzyme implicated in PGE2 catabolism. The present study was undertaken to investigate the contribution of visfatin, an adipose tissue-derived hormone, to the pathophysiology of OA, by examining its role in PGE2 synthesis and matrix degradation.

Stress-induced signaling pathways in hyalin chondrocytes: inhibition by Avocado-Soybean Unsaponifiables (ASU).

Objective: Avocado-Soybean Unsaponifiables (ASU) represent one of the most commonly used drugs for symptomatic osteoarthritis (OA). The mechanisms of its activities are still poorly understood. We investigate here the effects of ASU on signaling pathways in mouse or human chondrocytes.

Effect of widely used combinations of antiretroviral therapy on liver CYP3A4 activity in HIV-infected patients.

Aims: To evaluate the effects of combined antiretroviral drugs (HAART) on liver CYP3A4 activity using the [(14)C-N-methyl]-erythromycin breath test (ERMBT).

Methods: HIV-infected patients (31 women, 30 men) with mean (+/- SD) age of 38 +/- 9 years were enrolled and underwent complete clinical and laboratory evaluation. Patients were divided into five groups and were treated with two nucleoside analogues (NAs) and one of the following: nelfinavir alone (n = 13), any ritonavir-boosted protease inhibitor with (n = 8) or without (n = 13) nevirapine, nevirapine alone (n = 15), or a third NA (n = 12).

Involvement of central microsomal prostaglandin E synthase-1 in IL-1beta-induced anorexia.

In response to infection or inflammation, individuals develop a set of symptoms referred to as sickness behavior, which includes a decrease in food intake. The characterization of the molecular mechanisms underlying this hypophagia remains critical, because chronic anorexia may represent a significant health risk. Prostaglandins (PGs) constitute an important inflammatory mediator family whose levels increase in the brain during inflammatory states, and their involvement in inflammatory-induced anorexia has been proposed.

Immature murine articular chondrocytes in primary culture: a new tool for investigating cartilage.

Objective: Many genetically modified animal models are providing new keys for unlocking the pathophysiology of cartilage degradation. To produce a tool for cellular and molecular studies in genetically engineered murine models, we defined the optimal culture conditions for primary cultures of articular chondrocytes from newborn mice (C57Bl/6).

Methods: To determine whether the cultured cells exhibited the typical articular chondrocyte phenotype, we examined several morphological, biochemical, and functional features.

Up-regulation of microsomal prostaglandin E synthase 1 in osteoarthritic human cartilage: critical roles of the ERK-1/2 and p38 signaling pathways.

Objective: Microsomal prostaglandin E synthase 1 (mPGES-1) is the final enzyme of the cascade that produces prostaglandin E(2) (PGE(2)), a key actor in arthritis. To study mPGES-1 synthesis in human cartilage and its regulation by interleukin-1beta (IL-1beta), we used human cartilage and an immortalized human chondrocyte cell line. Furthermore, we investigated the signaling pathways involved in mPGES-1 expression.