Évaluation des dépenses énergétiques au quotidien chez les ongulés sauvages in natura : analyse bibliographique des éléments disponibles pour une approche additive

Les dépenses énergétiques des ongulés sauvages in natura doivent souvent être quantifiées par une approche indirecte qui les décompose en coûts : (i) de base, (ii) de thermorégulation, (iii) d'alimentation, (iv) de posture debout et d'activité, (v) de croissance et de reproduction. Les dépenses « au quotidien », objet de cette synthèse, correspondent aux quatre premiers compartiments; les données bibliographiques correspondantes, mesures, estimations et prédictions, sont rapportées et comparées; leurs conditions et limites d'utilisation sont discutées. Le niveau de base (sans thermorégulation, ni activité) devrait être estimé par le métabolisme dit « Standard » ou « de Base », délicat à mesurer, même en laboratoire, sur les animaux sauvages. C'est pourquoi d'autres estimations, plus ou moins assimilables à un métabolisme dit « de Repos », sont habituellement utilisées, bien que cette approche puisse être considérée comme moins rigoureuse. La formule de Kleiber (1961) prédit le métabolisme standard d'animaux adultes, Mammifères et Oiseaux principalement, en fonction de leur masse corporelles; des prédictions plus précises ont été mises au point, mais pour des catégories (d'espèce, d'âge, de sexe,...) particulières. La thermorégulation est le résultat d'interactions complexes entre diverses caractéristiques environnementales (température ambiante, humidité, vitesse du vent, rayonnement solaire) et de multiples paramètres relatifs à l'animal (surface offerte, isolation corporelle, état physiologique...). Si son coût peut être considéré comme nul à l'intérieur de ce qu'on appelle « zone de neutralité thermique » (ZNT), il augmente de part et d'autre, via la mise en œuvre de mécanismes physiologiques, chimiques et comportementaux très divers qui interviennent pour maintenir une température corporelle acceptable. Les expérimentations permettant de déterminer la nature et le coût des mécanismes mis en oeuvre exigent des sujets entraînés et un dispositif expérimental assez lourd; la transposition qualitative aux animaux libres en nature est, dans une certaine mesure, possible, la transposition quantitative est difficile. Le coût total d'alimentation inclut les coûts de posture debout et de recherche alimentaire, ainsi que ceux, plus spécifiques, de prise alimentaire (i.e. prélèvement, mastication, déglutition), de digestion et éventuellement de rumination. La nature de l'aliment peut certes, chez tous les ongulés, influer assez fortement sur le coût de prise alimentaire, mais ce sont les déplacements liés à la recherche alimentaire qui génèrent les dépenses les plus importantes chez les animaux sauvages en nature. Les coûts de posture debout et de locomotion (composantes essentielles de l'activité) ont été quantifiés chez de nombreuses espèces en comparant le métabolisme d'animaux debout et/ou en déplacement à celui d'animaux couchés. A partir de ces mesures, certains auteurs, Taylor et al. (1982) en particulier, ont proposé des formules prédictives pour évaluer le coût de locomotion en fonction de la masse corporelle. Des estimations de surcoût pour les déplacements en terrain difficile (pente, obstacles, neige, boue) ont également été rapportées. L'approche additive reste une modélisation dont la validité dépend largement de la qualité des estimations de dépenses disponibles et de la précision des paramètres d'activité recueillis sur les animaux cibles.Estimating the energy expenditures of wild ungulates in natura often requires an indirect approach splitting them within: (i) basal level, (ii) thermoregulation cast, (iii) feeding cast, (iv) standing and activity cast, (v) growth and reproduction cast. First, each of the costs can be measured (most often through respirometric technics) or estimated (from previously obtained values). Second, these amounts are summed up ("additive" approach) according to the activity budget of the animal. The present bibliographie review only deals with daily expenditures, namely costs (i) to (iv). Various measures (with comparative tables), estimations and [allometric] predictive equations are reported, and their accuracy and limits are discussed. Basal level (without thermoregulation and activity) should be estimated by Standard or Basal Metabolic Rate, but this is difficult to measure on wild animals, even in the laboratory. Other estimations, more or less close to Resting Metabolic Rate (RMR) are therefore often used, although they are Jess relevant. Kleiber' s equation (196 1 ) predicts the standard metabolism of adult animals, mainly mammals and birds, from their body mass; some more accurate models are available but for more limited species, age, sex, ... categories. Thermoregulation is the result of complex interactions between various environmental (air temperature, moisture, wind speed, solar radiation . . . ) and animal (body area, insulation, physiological condition, . . . ) parameters. Therefore, it is not possible to give more or less standardized costs as for other expenditures. Thermoregulation cast can be considered as null in the so called "Thermoneutral Zone, TNZ". It increases outside this zone because of various physiological, chemical and behavioural mechanisms acting to maintain acceptable deep body temperature. Determining the nature and measuring the cast of the involved mechanisms (which vary according to species, season, age and physical condition of animals) require experiments on trained animals and an heavy experimental device. Qualitative extent to ungulates in natura is somewhat possible, but quantitative extent is difficult. Total feeding cast includes standing and moving (food search) costs, and some more typical costs: "eating" (i.e. prehension, mastication and swallowing), digestion and possibly rumination. In all (domestic or wild) ungulates, the type of food consumed can modify the eating cast, but foraging trips (more or Jess inversely related to food availability) can obviously involve the most important incremental costs in wild ungulates. Standing and locomotion costs (the main components of activity costs) were quantified in various species by comparing the metabolism of lying, standing and moving animals. From these measures, some authors (particularly Taylor et al., 1982) modeled locomotion cast from body mass. Some estimations of incremental costs due to a difficult terrain (slope, obstacles, snow caver, mud) are also reported. The relevance of the additive approach in energetic studies mainly relies on the quality of the available measures or estimations of each cost and on the accuracy of the activity parameters that are obtained from target animals. Of the various expenditure components, locomotion appears to be the most suitable for comparative purposes; however, the accurate estimation of its cost requires data adequate to identify the right terrain used by the animals

Isolation of a wide range of minerals from a thermally treated plant: Equisetum arvense, a Mare’s tale

Silica is the second most abundant biomineral being exceeded in nature only by biogenic CaCO3. Many land plants (such as rice, cereals, cucumber, etc.) deposit silica in significant amounts to reinforce their tissues and as a systematic response to pathogen attack. One of the most ancient species of living vascular plants, Equisetum arvense is also able to take up and accumulate silica in all parts of the plant. Numerous methods have been developed for elimination of the organic material and/or metal ions present in plant material to isolate biogenic silica. However, depending on the chemical and/or physical treatment applied to branch or stem from Equisetum arvense; other mineral forms such glass-type materials (i.e. CaSiO3), salts (i.e. KCl) or luminescent materials can also be isolated from the plant material. In the current contribution, we show the chemical and/or thermal routes that lead to the formation of a number of different mineral types in addition to biogenic silica

History and symptom taking in contact lens fitting and aftercare.

AIM: To appraise history and symptom taking for contact lens consultations, to determine current practice and to make recommendations for best practice. METHOD: The peer reviewed academic literature was reviewed and the results informed a survey completed by 256 eye care practitioners (ECPs) on their current practice and influences. RESULTS: The last eye-test date, last contact lens aftercare (for existing wearers) and reason for visit are key questions for most ECPs. Detailed use of contact lens questions are more commonly applied in aftercares than when refitting patients who have previously discontinued wear (87% vs 56% use), whereas questions on ocular and general history, medication and lifestyle were generally more commonly utilised for new patients than in aftercares (72% vs 50%). 75% of ECPs requested patients bring a list of their medication to appointments. Differential diagnosis questioning was thorough in most ECPs (87% of relevant questions asked). Attempts to optimise compliance included oral instruction (95% always) and written patient instructions (95% at least sometimes). Abbreviations were used by 39% of respondents (26% used ones provided by a professional body). CONCLUSION: There is scope for more consistency in history and symptom taking for contact lens consultations and recommendations are made

International genome-wide meta-analysis identifies new primary biliary cirrhosis risk loci and targetable pathogenic pathways.

Primary biliary cirrhosis (PBC) is a classical autoimmune liver disease for which effective immunomodulatory therapy is lacking. Here we perform meta-analyses of discovery data sets from genome-wide association studies of European subjects (n=2,764 cases and 10,475 controls) followed by validation genotyping in an independent cohort (n=3,716 cases and 4,261 controls). We discover and validate six previously unknown risk loci for PBC (Pcombined<5 × 10(-8)) and used pathway analysis to identify JAK-STAT/IL12/IL27 signalling and cytokine-cytokine pathways, for which relevant therapies exist

Safety, immunogenicity, and efficacy of a COVID-19 vaccine (NVX-CoV2373) co-administered with seasonal influenza vaccines: an exploratory substudy of a randomised, observer-blinded, placebo-controlled, phase 3 trial

Background: Safety and immunogenicity of COVID-19 vaccines when co-administered with influenza vaccines have not yet been reported. Methods: A sub-study on influenza vaccine co-administration was conducted as part of the phase 3 randomised trial of NVX-CoV2373’s safety and efficacy; ~400 participants meeting main study entry criteria, with no contraindications to influenza vaccination, were enroled. After randomisation to receive NVX-CoV2373 or placebo, sub-study participants received an open-label influenza vaccine at the same time as the first dose of NVX-CoV2373. Reactogenicity was evaluated for 7 days post-vaccination plus monitoring for unsolicited adverse events (AEs), medically-attended AEs (MAAEs), and serious AEs (SAEs). Vaccine efficacy against COVID-19 was assessed. Findings: Sub-study participants were younger (median age 39; 6.7 % ≥65 years), more racially diverse, and had fewer comorbid conditions than main study participants. Reactogenicity events more common in co-administration group included tenderness (70.1% vs 57.6%) or pain (39.7% vs 29.3%) at injection site, fatigue (27.7% vs 19.4%), and muscle pain (28.3% vs 21.4%). Rates of unsolicited AEs, MAAEs, and SAEs were low and balanced between the two groups. Co-administration resulted in no change to influenza vaccine immune response, while a reduction in antibody responses to the NVX-CoV2373 vaccine was noted. Vaccine efficacy against COVID-19 was 87.5% (95% CI: -0.2, 98.4) in those 18-<65 years in the sub-study while efficacy in the main study was 89.8% (95% CI: 79.7, 95.5).  Interpretation: This is the first study to demonstrate safety, immunogenicity, and efficacy of a COVID-19 vaccine when co-administered with influenza vaccines

Multiancestry analysis of the HLA locus in Alzheimer’s and Parkinson’s diseases uncovers a shared adaptive immune response mediated by HLA-DRB1*04 subtypes

Across multiancestry groups, we analyzed Human Leukocyte Antigen (HLA) associations in over 176,000 individuals with Parkinson’s disease (PD) and Alzheimer’s disease (AD) versus controls. We demonstrate that the two diseases share the same protective association at the HLA locus. HLA-specific fine-mapping showed that hierarchical protective effects of HLA-DRB1*04 subtypes best accounted for the association, strongest with HLA-DRB1*04:04 and HLA-DRB1*04:07, and intermediary with HLA-DRB1*04:01 and HLA-DRB1*04:03. The same signal was associated with decreased neurofibrillary tangles in postmortem brains and was associated with reduced tau levels in cerebrospinal fluid and to a lower extent with increased Aβ42. Protective HLA-DRB1*04 subtypes strongly bound the aggregation-prone tau PHF6 sequence, however only when acetylated at a lysine (K311), a common posttranslational modification central to tau aggregation. An HLA-DRB1*04-mediated adaptive immune response decreases PD and AD risks, potentially by acting against tau, offering the possibility of therapeutic avenues

Fibrinogen-Like Protein 2/Fibroleukin Induces Long-Term Allograft Survival in a Rat Model through Regulatory B Cells

International audienceWe previously described that in a rat model of heart transplantation tolerance was dependent on CD8 + CD45RC low Tregs that over-expressed fibrinogen-like protein 2 (FGL2)/fibro-leukin. Little is known on the immunoregulatory properties of FGL2. Here we analyzed the transplantation tolerance mechanisms that are present in Lewis 1A rats treated with FGL2. Over-expression of FGL2 in vivo through adenovirus associated virus-mediated gene transfer without any further treatment resulted in inhibition of cardiac allograft rejection. Adoptive cell transfer of splenocytes from FGL2-treated rats with long-term graft survival (> 80 days) in animals that were transplanted with cardiac allografts inhibited acute and chronic organ rejection in a donor-specific and transferable tolerance manner, since iterative adoptive transfer up to a sixth consecutive recipient resulted in transplantation tolerance. Adoptive cell transfer also efficiently inhibited anti-donor antibody production. Analysis of all possible cell populations among splenocytes revealed that B lymphocytes were sufficient for this adoptive cell tolerance. These B cells were also capable of inhibiting the proliferation of CD4 + T cells in response to allogeneic stimuli. Moreover, gene transfer of FGL2 in B cell deficient rats did not prolong graft survival. Thus, this is the first description of FGL2 resulting in long-term allograft survival. Furthermore, allograft tolerance was transfer-able and B cells were the main cells responsible for this effect