Glucocorticoids for acute urticaria: study protocol for a double-blind non-inferiority randomised controlled trial

INTRODUCTION: This study protocol describes a trial designed to investigate whether antihistamine alone in patients with acute urticaria does not increase the 7-day Urticaria Activity Score (UAS7) in comparison with an association of antihistamine and glucocorticoids and reduces short-term relapses and chronic-induced urticaria. METHODS AND ANALYSIS: This is a prospective, double-blind, parallel-group, multicentre non-inferiority randomised controlled trial. Two-hundred and forty patients with acute urticaria admitted to emergency department will be randomised in a 1:1 ratio to receive levocetirizine or an association of levocetirizine and prednisone. Randomisation will be stratified by centre. The primary outcome will be the UAS7 at day 7. The secondary outcomes will encompass recurrence of hives and/or itch at day 7; occurrence of spontaneous hives or itch for >6 weeks; patients with angioedema at day 7, and 2, 6, 12 and 24 weeks; new emergency visits for acute urticaria recurrences at days 7 and 14, and 3 months; Dermatology Life Quality Index at days 7 and 14, and 3 and 6 months; and Chronic Urticaria Quality of Life Questionnaire at 6 weeks. ETHICS AND DISSEMINATION: The protocol has been approved by the and will be carried out in accordance with the Declaration of Helsinki and Good Clinical Practice guidelines. A steering committee will oversee the progress of the study. Findings will be disseminated through national and international scientific conferences and publication in peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT03545464

PRIMA subretinal wireless photovoltaic microchip implantation in non-human primate and feline models

Purpose To evaluate the surgical technique for subretinal implantation of two sizes of PRIMA photovoltaic wireless microchip in two animal models, and refine these surgical procedures for human trials. Methods Cats and Macaca fascicularis primates with healthy retina underwent vitrectomy surgery and were implanted with subretinal wireless photovoltaic microchip at the macula/central retina. The 1.5mm PRIMA chip was initially studied in feline eyes. PRIMA implant (2mm,1.5mm sizes) arrays were studied in primates. Feasibility of subretinal chip implantation was evaluated with a newly-developed surgical technique, with surgical complications and adverse events recorded. Results The 1.5mm implant was placed in the central retina of 11 feline eyes, with implantation duration 43-106 days. The 1.5mm implant was correctly positioned into central macula of 11 primate eyes, with follow-up periods of minimum 6 weeks (n = 11), 2 years (n = 2), and one eye for 3 years. One primate eye underwent multi-chip 1.5mm implantation using two 1.5mm chips. The 2mm implant was delivered to 4 primate eyes. Optical coherence tomography confirmed correct surgical placement of photovoltaic arrays in the subretinal space in all 26 eyes. Intraoperative complications in primate eyes included retinal tear, macular hole, retinal detachment, and vitreous hemorrhage that resolved spontaneously. Postoperatively, there was no case of significant ocular inflammation in the 1.5mm implant group. Conclusions We report subretinal implantation of 1.5mm and 2mm photovoltaic arrays in the central retina of feline and central macula of primate eyes with a low rate of device-related complications. The in vivo PRIMA implantation technique has been developed and refined for use for a 2mm PRIMA implant in ongoing human trials

Spatial distribution of Eucalyptus roots in a deep sandy soil in the Congo: relationship with the ability of the stand to take up water and nutrients

International audienc

Spatial distribution of Eucalyptus roots in a deep sandy soil in the Congo: relationship with the ability of the stand to take up water and nutrients

International audienc

Nutrient deficiency enhances the rate of short-term belowground transfer of nitrogen from Acacia mangium to Eucalyptus trees in mixed-species plantations

International audienceWhile a recent study showed that significant amounts of the nitrogen (N) requirements of young Eucalyptus trees can be provided by nitrogen-fixing trees (NFTs) in mixed-species plantations through short-term belowground N transfer, the consequences of soil fertility on this facilitation process remain unknown. We assessed the effect of fertilization on the percentage of N derived from transfer (%NDFT) from Acacia mangium trees to Eucalyptus trees in mixed-species plantations. A complete randomized block design with two treatments (fertilized vs unfertilized) and three blocks was set up in mixed-species plantations of A. mangium and Eucalyptus in Brazil, with 50% of each species at 2.5 m × 2.5 m spacing. Collection of litterfall and forest floor made it possible to estimate the annual N release from forest floor decomposition between 46 and 58 months after planting, close to harvest age. 15N-NO3- was injected into the stem of one dominant Acacia tree in each plot, 58 months after planting. The x(15N) values of Acacia and Eucalyptus fine roots sampled within 1.8 m of the labelled A. mangium tree were determined at 7, 14, 30 and 60 days after labelling. The x(15N) values in wood, bark, branch and leaf samples were also determined for the 6 labelled Acacia trees and their two closest Eucalyptus neighbours, just before and 60 days after labelling. The amount of N released from forest floor decomposition was 31% higher in fertilized (F+) than in unfertilized (F-) plots. Sixty days after labelling, the aboveground compartments of Eucalyptus trees were significantly 15N enriched in both treatments. The x(15N) values of Acacia fine roots were higher than background values from 7 days after labelling onwards in F+ and 30 days after labelling in F-. The x(15N) values of Eucalyptus fine roots were higher than background values in both treatments, from 30 days after labelling onwards. Mean %NDFT values were 18.0% in F+ and 33.9% in F- over the first 60 days after labelling, and 22.8% in F+ and 67.7% in F- from 30 to 60 days after labelling. Fertilization decreased short-term transfer belowground of N from Acacia trees to Eucalyptus trees. Our study suggests that belowground facilitation processes providing N from NFTs to Eucalyptus trees in mixed-species plantations are more pronounced in low-fertility soils than in nutrient-supplied stands

Mixed-species plantations of Acacia mangium and Eucalyptus grandis in Brazil: 2: Nitrogen accumulation in the stands and biological N2 fixation

International audienceThe sustainability of plantation forests is closely dependent on soil nitrogen availability in short-rotation forests established on low-fertility soils. Planting an understorey of nitrogen-fixing trees might be an attractive option for maintaining the N fertility of soils. The development of mono-specific stands of Acacia mangium (100A:0E) and Eucalyptus grandis (0A:100E) was compared with mixed-species plantations, where A. mangium was planted in a mixture at a density of 50% of that of E. grandis (50A:100E). N2 fixation by A. mangium was quantified in 100A:0E and 50A:100E at age 18 and 30 months by the 15N natural abundance method and in 50A:100E at age 30 months by the 15N dilution method. The consistency of results obtained by isotopic methods was checked against observations of nodulation, Specific Acetylene Reduction Activity (SARA), as well as the dynamics of N accumulation within both species. The different tree components (leaves, branches, stems, stumps, coarse roots, medium-sized roots and fine roots) were sampled on 5–10 trees per species for each age. Litter fall was assessed up to 30 months after planting and used to estimate fine root mortality. Higher N concentrations in A. mangium tree components than in E. grandis might be a result of N2 fixation. However, no evidence of N transfer from A. mangium to E. grandis was found. SARA values were not significantly different in 100A:0E and 50A:100E but the biomass of nodules was 20–30 times higher in 100A:0E than in 50A:100E. At age 18 months, higher δ15N values found in A. mangium tree components than in E. grandis components prevented reliable estimations of the percentage of N derived from atmospheric fixation (%Ndfa). At age 30 months, %Ndfa estimated by natural abundance and by 15N dilution amounted to 10–20 and 60%, respectively. The amount of N derived from N2 fixation in the standing biomass was estimated at 62 kg N ha−1 in 100A:0E and 3 kg N ha−1 in 50A:100E by the 15N natural abundance method, and 16 kg N ha−1 in 50A:100E by the 15N dilution method. The total amount of atmospheric N2 fixed since planting (including fine root mortality and litter fall) was estimated at 66 kg N ha−1 in 100A:0E and 7 kg N ha−1 in 50A:100E by the 15N natural abundance method, and 31 kg N ha−1 in 50A:100E by the 15N dilution method. The most reliable estimation of N2 fixation was likely to be achieved using the 15N dilution method and sampling the whole plant

Climate change and agriculture worldwilde

Tropical tree plantations are rapidly expanding to meet the growing demand for wood and nonwood forest products. Current research-combining ecophysiology, genetics and functional genomics-aims to enhance the climate change mitigation role of these plantations and their adaptation. The positive effect of the increase in atmospheric carbon dioxide concentration on photosynthesis could boost biomass production, but the higher water and nutrient needs will have to be fulfilled to ensure the sustainability of this positive effect. Multispecies plantations benefitting from positive interactions between species could help maintain production in tropical tree plantations against a background of increasing biotic and abiotic stress