Relationships between hydro-climatology characteristics and karst spring triggering

International audienceThe Mediterranean region is characterized by the presence of small catchments and intermittent water streams. Karst springs play an important role on the definition of river dynamics either in the temporal or spatial aspects, consequently, the intermittence of the river is explained by the karst springs regimes. This work aims at understanding the relationships between the triggering of water flow on karst springs with climatic characteristics, by the example of the Vène river karst springs (South-east Mediterranean coast of France). Climatic variables were calculated from rainfall characteristics such as height, intensity, duration, and antecedent cumulated amounts. The analysis of the springs' hydrographs allowed distinguishing rainfall events that could trigger the water flow on karst springs from rainfall events that could not trigger them. The results showed that the water flow triggering at the main spring was mainly related to cumulative rainfall amounts before the occurrence of the triggering rainfall event. This study contributed to a better understanding of the karst springs responses to climatic factors

Nutrient load modelling during floods in intermittent rivers: An operational approach

International audienceIn the Mediterranean area, lagoons and coastal waters are often under the influence of intermittent rivers that contribute the majority of pollutant loads during flood events. Reliable tools for evaluating pollutant loads from land sources are needed for managing the water quality of the receiving waters, but available water quality models are not suitable for simulating these flash flood events. An operational tool, D-PoL (Diffuse-Pollution Load), to estimate the pollutant loads transferred during rainfall events by small Mediterranean rivers is described. The tool is based on a rainfall-load semi-distributed approach and was developed with the aim of simulating temporal variations in fluxes of dissolved pollutants. The model simulates pollutographs at the outlet of the catchment during rainfall events: the rainfall triggers the processes.The model can be described as a rainfall-load model. Three parameters describe the processes involved: the initial stock of pollutants on the hillslopes, the production parameter (which is related to the lag time of the catchment) and the routing parameter (which is related to the lag time of a basic river reach). First, sensitivity analysis demonstrated that each of the parameters controlled one key-feature of the pollutograph. The initial stock of pollutants influenced the amplitude of the pollutograph, the production parameter controlled the recession period, and the routing parameter influenced the rising phase. Second, the model was calibrated for dissolved inorganic nitrogen and dissolved phosphorus on a 20-flood data set. The sets of optimal parameters were fitted to empirical relationships for both elements. On the 20-flood calibration data set, the simulated total loads with adjusted parameters compared well with the observed parameters, except for very small events. Finally, the D-PoL model was checked against a new set of data, a 10-flood validation data set. This final validation of the model showed that the dynamics of the pollutograph were not perfectly reproduced, but that simulated total loads agreed with the observed loads

Anti-biofilm activity of a semi-synthetic molecule obtained from resveratrol against Candida albicans biofilm

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Neuroprotective Effect of Eco-Sustainably Extracted Grape Polyphenols in Neonatal Hypoxia-Ischemia.

International audiencePolyphenols are natural compounds with promising prophylactic and therapeutic applications. However, their methods of extraction, using organic solvents, may prove to be unsuitable for daily consumption or for certain medical indications. Here, we describe the neuroprotective effects of grape polyphenols extracted in an eco-sustainable manner in a rat model of neonatal hypoxia-ischemia (NHI). Polyphenols (resveratrol, pterostilben and viniferin) were obtained using a subcritical water extraction technology to avoid organic solvents and heavy metals associated with chemical synthesis processes. A resveratrol or a polyphenol cocktail were administered to pregnant females at a nutritional dose and different time windows, prior to induction of NHI in pups. Reduced brain edema and lesion volumes were observed in rat pups whose mothers were supplemented with polyphenols. Moreover, the preservation of motor and cognitive functions (including learning and memory) was evidenced in the same animals. Our results pave the way to the use of polyphenols to prevent brain lesions and their associated deficits that follow NHI, which is a major cause of neonatal death and disabilities

Trans ε-Viniferin Decreases Amyloid Deposits With Greater Efficiency Than Resveratrol in an Alzheimer’s Mouse Model

International audienceIn a previous study, we showed that viniferin decreased amyloid deposits and reduced neuroinflammation in APPswePS1dE9 transgenic mice between 3 and 6 months of age. In the present study, wild type and APPswePS1dE9 transgenic mice were treated from 7 to 11 or from 3 to 12 months by a weekly intraperitoneal injection of either 20 mg/kg viniferin or resveratrol or their vehicle, the polyethylene glycol 200 (PEG 200). The cognitive status of the mice was evaluated by the Morris water maze test. Then, amyloid burden and neuroinflammation were quantified by western-blot, Enzyme-Linked ImmunoSorbent Assay (ELISA), immunofluorescence, and in vivo micro-Positon Emission Tomography (PET) imaging. Viniferin decreased hippocampal amyloid load and deposits with greater efficiency than resveratrol, and both treatments partially prevented the cognitive decline. Furthermore, a significant decrease in brain uptake of the TSPO PET tracer [ 18 F]DPA-714 was observed with viniferin compared to resveratrol. Expression of GFAP, IBA1, and IL-1β were decreased by viniferin but PEG 200, which was very recently shown to be a neuroinflammatory inducer, masked the neuroprotective power of viniferin

Analyse du rôle de l'information climatique pour la détermination de l'évapotranspiration dans la modélisation pluie-débit. Rapport final - Années 2001-2002

The objective of this project was to bring light on the problems of using potential evapotranspiration (PE) as input to rainfall-runoff models and to assess the relevance of this variable in this modelling context. The tests carried out in this project are based on several rainfall-runoff models that were run on large databases with either general or regional climatic characteristics. The tests have shown that using a simple PE formulation only based on temperature as measured variable can give as good results as using a more complex combinatory formulation like the Penman one. Besides, results show that rainfall-runoff models are not able to make a better use of more detailed PE information, either on a temporal or a spatial point of view. One reason is the incapacity of their production function to exploit this extra information. In a Mediterranean context, it is even possible to use a constant limit PE as an optimised parameter instead of using actual PE data.L'objectif de ce projet de recherche était d'apporter un éclairage sur les problèmes d'utilisation de l'évapotranspiration potentielle (ETP) comme forçage climatique dans les modèles pluie-débit et d'évaluer la pertinence de l'utilisation de cette variable dans le contexte de la modélisation pluie-débit. Les travaux réalisés dans le cadre du projet PNRH se sont appuyés sur plusieurs modèles pluie-débit et diverses formulations d'ETP, qui ont été appliqués sur d'importantes bases de données dont les caractéristiques se voulaient soit générales, soit régionales suivant la particularité des questions abordées. Les tests réalisés ont permis de montrer qu'une formulation simple de l'ETP ne faisant intervenir que la température comme variable mesurée permet d'obtenir d'aussi bons résultats que des formules plus complexes basées sur des approches combinatoires de type Penman. Par ailleurs, les résultats montrent que les modèles pluie-débit ne sont pas capables d'exploiter une information détaillée d'ETP, que ce soit d'un point de vue temporel (ETP datée) ou d'un point de vue spatial (information distribuée de l'ETP). Une raison avancée est l'incapacité de leur fonction de production à réaliser une telle exploitation. Dans un contexte méditerranéen, le modèle peut même se contenter d'une évaporation limite constante comme paramètre optimisé

Synthesis, Conformational Analysis, and Complexation Study of an Iminosugar-Aza-Crown, a Sweet Chiral Cyclam Analog

International audienceA new family of chiral C2 symmetric tetraazamacrocycles, coined ISAC for IminoSugar Aza-Crown, incorporating two iminosugars adopting a 4C1 conformation is disclosed. Multinuclear NMR experiments on the corresponding Cd2+ complex show that the ISAC is a strong chelator in water and its tetramine cavity adopts a conformation similar to that of the parent Cd–cyclam complex. Similar behavior is observed with Cu2+ in solution, with enhanced stability compared to the Cu–cyclam complex

Comparison of arterial wall integration of different flow diverters in rabbits: The CICAFLOW study

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Longitudinally Extensive Myelitis Associated With Immune Checkpoint Inhibitors

International audienceObjective: To define the characteristics and the outcome of myelitis associated with immune checkpoint inhibitors (ICIs).Methods: We performed a retrospective research in the databases of the French Pharmacovigilance Agency and the OncoNeuroTox network for patients who developed myelitis following treatment with ICIs (2011-2020). A systematic review of the literature was performed to identify similar cases.Results: We identified 7 patients who developed myelitis after treatment with ICIs (anti-PD1 [n = 6], anti-PD1 + anti-CTLA4 [n = 1]). Neurologic symptoms included paraparesis (100%), sphincter dysfunction (86%), tactile/thermic sensory disturbances (71%), and proprioceptive ataxia (43%). At the peak of symptom severity, all patients were nonambulatory. MRI typically showed longitudinally extensive lesions, with patchy contrast enhancement. CSF invariably showed inflammatory findings. Five patients (71%) had clinical and/or paraclinical evidence of concomitant cerebral, meningeal, caudal roots, and/or peripheral nerve involvement. Despite the prompt discontinuation of ICIs and administration of high-dose glucocorticoids (n = 7), most patients needed second-line immune therapies (n = 5) because of poor recovery or early relapses. At last follow-up, only 3 patients had regained an ambulatory status (43%). Literature review identified 13 previously reported cases, showing similar clinical and paraclinical features. All patients discontinued ICIs and received high-dose glucocorticoids, with the addition of other immune therapies in 8. Clinical improvement was reported for 10 patients.Conclusion: Myelitis is a rare but severe complication of ICIs that shows limited response to glucocorticoids. Considering the poor functional outcome associated with longitudinally extensive myelitis, strong and protracted immune therapy combinations are probably needed upfront to improve patient outcome and prevent early relapses

O04/35 Comparison of arterial wall integration of different flow diverters in rabbits : the cicaflow study

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