Mechanical characterization and comparison of different NiTi/silicone rubber interfaces

International audienceThis paper investigates the effects of different surface treatments on the mechanical resistance of interface between wires of NiTi shape memory alloy and silicone rubber. Three different treatments were used; primer, plasma and combination of both. The wires deoxidation effects have also been studied. In order to characterize the interface properties in such composite material, pull-out tests were carried out by means of a home-made device. This test allows us to evaluate the mechanical resistance of the interface in terms of the maximum force reached during the test. First, results show that the debonding force is not higher after the wires deoxidation. This preparation is therefore not necessary. Second, using a primer PM820 and plasma separately leads to a significant improvment of the mechanical resistance. Third, the combination of these treatments (primer followed by plasma) and a longer time of exposure to the plasma alone get the debonding force higher. Consequently, NiTi/silicone rubber interface improved only by means of plasma offers a new way to obtain biocompatible interfaces in such composite material

Adipose Tissue Is a Neglected Viral Reservoir and an Inflammatory Site during Chronic HIV and SIV Infection

International audienceTwo of the crucial aspects of human immunodeficiency virus (HIV) infection are (i) viral persistence in reservoirs (precluding viral eradication) and (ii) chronic inflammation (directly associated with all-cause morbidities in antiretroviral therapy (ART)-controlled HIV-infected patients). The objective of the present study was to assess the potential involvement of adipose tissue in these two aspects. Adipose tissue is composed of adipocytes and the stromal vascular fraction (SVF); the latter comprises immune cells such as CD4+ T cells and macrophages (both of which are important target cells for HIV). The inflammatory potential of adipose tissue has been extensively described in the context of obesity. During HIV infection, the inflammatory profile of adipose tissue has been revealed by the occurrence of lipodystrophies (primarily related to ART). Data on the impact of HIV on the SVF (especially in individuals not receiving ART) are scarce. We first analyzed the impact of simian immunodeficiency virus (SIV) infection on abdominal subcutaneous and visceral adipose tissues in SIVmac251 infected macaques and found that both adipocytes and adipose tissue immune cells were affected. The adipocyte density was elevated, and adipose tissue immune cells presented enhanced immune activation and/or inflammatory profiles. We detected cell-associated SIV DNA and RNA in the SVF and in sorted CD4+ T cells and macrophages from adipose tissue. We demonstrated that SVF cells (including CD4+ T cells) are infected in ART-controlled HIV-infected patients. Importantly, the production of HIV RNA was detected by in situ hybridization, and after the in vitro reactivation of sorted CD4+ T cells from adipose tissue. We thus identified adipose tissue as a crucial cofactor in both viral persistence and chronic immune activation/inflammation during HIV infection. These observations open up new therapeutic strategies for limiting the size of the viral reservoir and decreasing low-grade chronic inflammation via the modulation of adipose tissue-related pathway

Régulation de l'activité d'effecteurs cellulaires de la réponse immunitaire innée par interaction des récepteurs inhibiteurs ILT2 et ILT4 avec la molécule HLA-G

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Long-Term Effectiveness of a Lifestyle Intervention for the Primary Prevention of Type 2 Diabetes in a Low Socio-Economic Community – An Intervention Follow-Up Study on Reunion Island

Cet article est accompagné de 4 annexes publiées en ligne (Supporting Information) et disponibles au téléchargement à l'adresse suivante :doi:10.1371/journal.pone.0146095International audienceIn type 2 diabetes (T2D) prevention research, evidence for maintenance of risk factor reduction after three years of follow-up is needed. The objective of this study was to evaluate the long-term effectiveness of a combined lifestyle intervention aiming at controlling body weight (BW) and waist circumference (WC) in non-diabetic, overweight/obese adults living in a low socioeconomic community. On Reunion Island, 445 adults living in deprived areas, aged 18–40 and at high-risk for T2D, were included in an intervention versus control trial for primary prevention (2001–2002). The intervention promoted a healthy diet and moderate regular physical activity, through actions strengthening individuals or community and improving living conditions. The control group received a one-shot medical information and nutritional advices. After the end of the trial (2003), 259 of the subjects participated in a follow-up study (2010– 2011). The outcomes were the nine-year changes from baseline in BW, body mass index (BMI) and WC measurements, separately. Statistical analyses were performed on an intention to treat basis, using available and imputed datasets. At inclusion, T2D risk factors were prevalent: family history of diabetes in first-degree relatives (42%), women with a personal history of gestational diabetes (11%), total obesity (43%, median BMI 29.1 kg/m²) and central obesity (71%). At follow-up, the adjusted effect on imputed dataset was significant for WC-2.4 cm (95% confidence interval:-4.7 to-0.0 cm, p = 0.046), non-significant for BW-2.2 kg (-4.6 to +0.2 kg, p = 0.073) and BMI-0.81 kg/m² (-1.69 to +0.08 kg/m², p = 0.074). A specific long-term effect was the increased likelihood of reduction in adiposity: BW loss, BMI reduction , and WC reduction were more frequent in the intervention group. In the context of low socio-economic communities, our data support the assumption of long-term effect of lifestyle interventions targeting total obesity and central obesity two major drivers of T2D

Study of scratch resistance of a hard-on-soft polymer bilayer: Combination of in situ vision, X-ray tomography and numerical simulations

International audienceThe deposition of a hard coating is a commonly used solution to increase the scratch resistance of soft polymeric materials at low and moderate normal loads. But the major risk for a coating subjected to tribological stresses is to crack and spall off. In this study, the influence on scratch behavior of a hard polyurethane coating on a plasticized PVC substrate has been investigated. At low load, the hard coating allows decreasing the plastic deformation of the substrate, and a geometrical interpretation is proposed. At increasing loads, this coating shows three fracture mechanisms: first, cracks oriented at 45° to the scratch direction starting near the detachment point behind the tip, on the edge of the scratch; then, in addition to this first mechanism, tearing under the tip forming a central crack parallel to the scratch direction; finally, in addition to the first two mechanisms, a circular crack forms ahead of the indentor by a bending effect at the top of the frontal bulge. These mechanisms are observed in situ thanks to a microscope coupled to a camera. Then, the scratches are observed by X-Ray tomography in order to analyze crack propagation in the depth of the material. Finally a numerical model of the scratch test has been developed. The combination of the three techniques gives a precise insight into the local mechanical conditions that lead up to these different kinds of scratches

Ecological effects of natural hazards and human activities on the Ecuadorian Pacific coast during the late Holocene

International audienceThe La Tolita archeological site is located in the Province of Esmeraldas in the northwestern part of Ecuador at the border with Colombia. This area comprises one of the world's wettest coastal regions with mangrove and swamps along the coast and has one of the richest tropical rainforest of the planet, extending inland. Today this region is seriously affected by natural hazards including earthquakes, deposition of thick layers of volcanic ash, tsunamis, and El Niño flooding. The region also hosted one of the most important and famous cultures of the late Holocene, the La Tolita–Tumaco, which dominated northern South America between 2900 and 1100 yr BP. With the aim of characterizing the influence on the environment of the different factors of natural hazards, climate changes, and human activities, we drilled a 4-m long sediment core in a swamp close to the La Tolita site. The record dates back to 5000 years BP. Multiproxy analyses of pollen, microcharcoal, XRF-based geochemical data, and geochronology were performed on the sediment to distinguish the different drivers of change. At ~ 3000 yr BP, an earthquake dramatically modified the landscape, elevating the ground and changing the course of the rivers. In the following two millennia until 1100 yr BP, raised-field agricultural activities dominated the site, providing evidence for an increase in the local population. Human activity progressively declined after 1100 yr BP, with the loss of the regional influence of the Tolita culture. The climate remained permanently moist throughout the sediment record, both the rainforest and the mangrove remained well developed, and marine incursions were short and frequent

HLA-G1 and HLA-G5 active dimers are present in malignant cells and effusions: The influence of the tumor microenvironment

International audienceDimers of the nonclassical HLA-G class I molecule have recently been shown to be active structures that mediate inhibition of NK-cell cytotoxic activity through interaction with the immunoglobulin-like transcript (ILT)-2 inhibitory receptor. However, this has only been proven in trophoblasts and HLA-G transfectants. Here, we document for the first time the existence of HLA-G dimers in cancer. Indeed, we identified both surface and soluble HLA-G dimers in tumor cells and malignant ascites respectively. Interestingly, factors from the tumor microenvironment, such as interferons, enhanced the formation of HLA-G dimers and increased the protection of tumors from NK cell-mediated lysis. These data emphasize the impact of HLA-G conformation on its efficiency at inhibitingthe antitumor response and thus favoring tumor progression. In view of these results, the effect of the tumor microenvironment on upregulation of HLA-G function deserves particular attention when designing cancer immunotherapy protocols

Retrospective analyses of fox feces by real-time PCR to identify new endemic areas of Echinococcus multilocularis in France.

International audienceAlveolar echinococcosis is considered to be the most serious zoonosis in the Northern Hemisphere's cold or temperate regions. In Europe, the parasite has a sylvatic life cycle based on predator-prey interactions, mainly between red foxes and small rodents. Echinococcus multilocularis has been observed to have spread across Europe over the last three decades. In France, a westward spread of the parasite's known endemic areas has been described. In this study, a retrospective analysis of fox feces by real-time PCR was carried out in four départements not previously investigated and considered free along with two endemic control departments. The fox feces collected from 2000 to 2004 were analyzed by real-time PCR. Fecal prevalence in the two endemic departments of Doubs and Côte d'Or were estimated at 12 % [6.4-20.0 %] and 4.2 % [1.1-10.3 %], respectively. No positive samples were identified among the 72 feces collected in Drôme or the 112 from Allier, which is consistent with the very low expected prevalence should the parasite be present. Three positive samples were recovered in the Seine-Maritime and Hautes-Alpes départements, resulting in a prevalence of 3.5 % [0.7-10.0 %] and 2.5 % [0.5-7.1 %], respectively. From now on, Hautes-Alpes constitutes the new southern border of the endemic areas in France and confirms the southward expansion previously highlighted. Real-time copro-PCR proved useful in identifying new endemic areas even with low prevalence. Due to the spread of E. multilocularis in France and associated zoonotic risk, it is necessary to expand surveillance in order to fully define all the country's endemic areas. On a continental scale, the development and harmonization of surveillance programs are now needed in order to obtain a global overview of the presence of E. multilocularis and to tailor potential countermeasures

Functional specialization of short-lived and long-lived macrophage subsets in human tonsils

International audienceMacrophages play a central role in tissue homeostasis and host defense. However, the properties of human macrophages in non-diseased tissues remain poorly understood. Here, we characterized human tonsil macrophages and identified three subsets with distinct phenotype, transcriptome, life cycle, and function. CD36hi macrophages were related to monocytes, while CD36lo macrophages showed features of embryonic origin and CD36int macrophages had a mixed profile. scRNA-seq on non-human primate tonsils showed that monocyte recruitment did not pre-exist an immune challenge. Functionally, CD36hi macrophages were specialized for stimulating T follicular helper cells, by producing Activin A. Combining reconstruction of ligand-receptor interactions and functional assays, we identified stromal cell-derived TNF-α as an inducer of Activin A secretion. However, only CD36hi macrophages were primed for Activin A expression, via the activity of IRF1. Our results provide insight into the heterogeneity of human lymphoid organ macrophages and show that tonsil CD36hi macrophage specialization is the result of both intrinsic features and interaction with stromal cells