Secreted enzymatic activities of ectomycorrhizal fungi as a case study of functional diversity and functional redundancy

• Introduction : Many studies deal with taxonomic diversity (TD) or estimation of functional traits of ectomycorrhizal communities. However, to our knowledge, none of them has ever tried to calculate the functional diversity (FD) of those communities, which is of critical importance for the diversity and reliability of nutrient supply to the tree. • Objectives : Here, we propose to evaluate the functional diversity of ECM communities in their potential ability to mobilise nutrients from organic matter, in two different forest stands. • Results : Results show that in both forest stands: TD is strongly correlated with FD.ECM species are functionally redundant within the communities for their abilities to secrete organic matter degrading enzymes.The functional traits (enzymatic activities) of the studied ectomycorrhizal communities are not related within genera, nor within families or phylogenetically related groups of taxa.Some species show a wide phenotypic plasticity for their enzymatic profiles. • Conclusion : This study provides the first evidence of functional redundancy in ectomycorrhizal communities. More studies are now needed to evaluate the robustness of these results at wider ecosystem scales and using other relevant functional trait

Courbes d'apprentissage des internes pour la pratique de l'anesthésie loco-régionale sous échographie : étude CAPPRI

L'utilisation de l'échographie s'est imposée en anesthésie loco-régionale (ALR). Son apprentissage par les internes s'effectue le plus souvent au lit du patient mais n'a pas été évalué dans ce contexte. L'objectif de ce travail était de réaliser les courbes d'apprentissage des internes pour la réalisation échoguidée des principaux blocs nerveux périphériques. Dans une étude prospective observationnelle, 8 internes d anesthésie inexpérimentés en ALR échoguidée ont été inclus pendant leur stage de 3 mois en chirurgie orthopédique. Tous les blocs interscaléniques, axillaires, fémoraux et sciatiques étaient inclus et réalisés sous échographie. Pour chaque type de bloc, une courbe évaluant l efficacité des blocs et une courbe évaluant le temps de réalisation (temps inférieur au 75ème percentile de celui de 2 experts) étaient réalisées. Ces temps étaient aussi comparés à ceux des experts et les erreurs ont été analysées. 522 blocs ont été inclus. 91% étaient efficaces, dont plus de 80 % dès les 5 premiers blocs réalisés. Sur le critère de temps, le taux de succès était supérieur à 80% après 25 blocs interscaléniques et fémoraux et après 20 blocs sciatiques. Le temps de réalisation des blocs n était plus différent entre les internes et les experts après 15 blocs de chaque type. La mauvaise visualisation du bout d aiguille était l erreur la plus fréquente (26%) et persistait jusqu à la fin du stage avec une association significative avec les échecs (p<0.0001). L apprentissage de l ALR échoguidée est rapide mais nécessite probablement entre 20 et 25 blocs de chaque type pour atteindre une performance comparable à celle des experts.Learning of ultrasound (US) guided regional anesthesia differs from learning of regional anesthesia using nerve stimulation. The aim of our study was to determine for the main peripheral nerve blocks, the attempts number required by inexperienced anesthesiology residents at bedside to acquire competency in regional anesthesia using US. In a prospective observational study, 8 inexperienced residents were included. All interscalene, axillary, femoral and sciatic blocks were included and performed using US guidance. 2 types of learning curves were constructed for each type of block : learning curves assessing block efficiency and learning curves assessing execution times (rates of efficient blocks with an execution time less than the 75th percentil of that of 2 experts). Execution times were also compared with that of experts and errors distribution during learning was studied. 522 blocks were included. 91% of blocks were efficient and more than 80% at the beginning of the learning. On the criterion of execution time, success rates were greater than 80% after 25 blocks for interscalene and femoral blocks and after 20 blocks for sciatic block. There was no significant difference between experts and residents execution times after the 15th attempt of each block type. Poor visualization of the needle tip was the most frequent error (26% of blocks) and persisted until the end of the course with a significant association with failed blocks (p < 0.0001). Learning of regional anesthesia using US is fast, but requires a number between 20 and 25 blocks of each type to acquire comparable performance to those of experts in terms of block efficiency and execution time.ANGERS-BU Médecine-Pharmacie (490072105) / SudocSudocFranceF

Secreted enzymatic activities of ectomycorrhizal fungi as a case study of functional diversity and functional redundancy

Introduction Many studies deal with taxonomic diversity (TD) or estimation of functional traits of ectomycorrhizal communities. However, to our knowledge, none of them has ever tried to calculate the functional diversity (FD) of those communities, which is of critical importance for the diversity and reliability of nutrient supply to the tree. Objectives Here, we propose to evaluate the functional diversity of ECM communities in their potential ability to mobilise nutrients from organic matter, in two different forest stands. Results Results show that in both forest stands: TD is strongly correlated with FD. ECM species are functionally redundant within the communities for their abilities to secrete organic matter degrading enzymes. The functional traits (enzymatic activities) of the studied ectomycorrhizal communities are not related within genera, nor within families or phylogenetically related groups of taxa. Some species show a wide phenotypic plasticity for their enzymatic profiles. Conclusion This study provides the first evidence of functional redundancy in ectomycorrhizal communities. More studies are now needed to evaluate the robustness of these results at wider ecosystem scales and using other relevant functional traits

Iron is essential for living!

International audienceIron as an element is a double-edged sword, essential for living but also potentially toxic through the generation of oxidative stress. The recent study by Chen and colleagues in Critical Care reminds us of this elegantly. In a mouse model of acute lung injury, they showed that silencing hepcidin (the master regulator of iron metabolism) locally in airway epithelial cells aggravates lung injury by increasing the release of iron from alveolar macrophages, which in turn enhances pulmonary bacterial growth and reduces the macrophages’ killing properties. This work underscores that hepcidin acts not only systematically (as a hormone) but also locally for iron metabolism regulation. This opens areas of research for sepsis treatment but also for iron deficiency or anaemia treatment, since the local and systemic iron regulation appear to be independent.</p

Simple microplate assays to measure iron mobilization and oxalate secretion by ectomycorrhizal tree roots

International audienceThe ability of ectomycorrhizal (ECM) fungi to mobilize soil inorganic nutrients has been well documented for a diversity of species. However, most of these studies were performed with tree seedlings or fungal cultures, making them hardly comparable. We propose here three microplate assays to compare iron chelation, free iron uptake and oxalate production by ECMs freshly sampled in mature forest ecosystems. These assays proved to be sensitive enough to detect significant differences between two common ECM types. Lactarius subdulcis was less efficient than Xerocomus sp. for accessing to free or complexed iron, but produced 100 times more oxalate. These preliminary results open the way to study the contribution of ECM communities to nutrient cycling in forest ecosystems

Safety of changes in the use of noninvasive ventilation and high flow oxygen therapy on reintubation in a surgical intensive care unit: A retrospective cohort study.

Reintubation after weaning from mechanical ventilation is relatively common and is associated with poor outcomes. Different methods to decrease the reintubation rate post extubation, including noninvasive ventilation, and more recently high-flow oxygen (HFO) therapy, have been proposed. In this study, we aimed to assess the safety of introducing HFO in the post-extubation care of intensive care unit (ICU) patients. We conducted a single-center cohort study of extubated adult patients hospitalized in a surgical ICU and previously mechanically ventilated for > 1 day. Our study consisted of two phases: Phase 1 (before the introduction of HFO from April 2015 to April 2016) and Phase P2 (after the introduction of HFO from April 2017 to April 2018). The primary endpoint was the reintubation rate within 48 hours of extubation. In total, 290 patients (median age 65 years [50-74]; 190 men [65.5%]) were included in the analysis (181 and 109 in Phases 1 and 2, respectively). The results of the post-extubation use of noninvasive methods (noninvasive ventilation and/or HFO) were not significantly different between the two phases (41 [22.7%] versus 29 [26.6%] patients; p = 0.480), however these methods were implemented earlier in Phase 2 (0 versus 4 hours; p = 0.009) and HFO was used significantly more often than noninvasive ventilation (24 [22.0%] versus 25 [13.8%] patients; p = 0.039). The need for reintubation within 48 hours post extubation was significantly lower in Phase 2 (4 [3.7%] versus 20 [11.0%] patients; p = 0.028) but was not significantly different at 7 days post extubation (10 [9.2%] versus 30 [16.6%] patients; p = 0.082). The earlier implementation of noninvasive methods and the increased use of HFO beginning in Phase 2 were safe and effective based on the reintubation rates within the first 48 hours post extubation and after 7 days

Additional file 1 of Sufentanil sublingual tablet system for enhanced recovery after total knee arthroplasty: a prospective observational case study

Additional file 1: Table S1. Postoperative data related to pain and mobilization in patients operated on under general anesthesia

Iron Deficiency without Anemia Decreases Physical Endurance and Mitochondrial Complex I Activity of Oxidative Skeletal Muscle in the Mouse

Iron deficiency (ID), with or without anemia, is responsible for physical fatigue. This effect may be linked to an alteration of mitochondrial metabolism. Our aim was to assess the impact of ID on skeletal striated muscle mitochondrial metabolism. Iron-deficient non-anemic mice, obtained using a bloodletting followed by a low-iron diet for three weeks, were compared to control mice. Endurance was assessed using a one-hour submaximal exercise on a Rotarod device and activities of mitochondrial complexes I and IV were measured by spectrophotometry on two types of skeletal striated muscles, the soleus and the quadriceps. As expected, ID mice displayed hematologic markers of ID and reduced iron stores, although none of them were anemic. In ID mice, endurance was significantly reduced and activity of the respiratory chain complex I, normalized to citrate synthase activity, was significantly reduced in the soleus muscle but not in the quadriceps. Complex IV activities were not significantly different, neither in the soleus nor in the quadriceps. We conclude that ID without anemia is responsible for impaired mitochondrial complex I activity in skeletal muscles with predominant oxidative metabolism. These results bring pathophysiological support to explain the improved physical activity observed when correcting ID in human. Further studies are needed to explore the mechanisms underlying this decrease in complex I activity and to assess the role of iron therapy on muscle mitochondrial metabolism