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International audience; The purpose of this work was to: (i) propose a methodology to infer local estimates of the available water capacity (AWC) at a plot from a few measurements in laboratory of AWC carried out on horizons of a pit on the same plot, (ii) examine the effect of measurement errors on spatial estimates of AWC and the associated uncertainties. For each horizon identified in the pit, the water content was determined at field capacity and at the permanent wilting point, and thus AWC. 47 soundings were carried out on a regular grid covering the plot. For each sounding, an AWC value was estimated by matching sounding horizons to the pit horizons. Laboratory measurements of AWC on 14 sites were used to validate the 47 local estimates. Statistics such as correlation coefficient, mean error and root mean square error are promising at 0.84, 4.0 mm and 17.5 mm, respectively. The spatialization of AWC was carried out by ordinary kriging, considering or ignoring the measurement errors on AWC. The precision of AWC estimates allowed making evident that accounting for measurement errors provided estimates that were more precise. This result, confirmed by the prediction interval coverage probability statistic, underlined that taking into account measurement errors in spatial modeling is an effective way to reduce the confidence interval of any estimate. These results suggest that it would be better to fix the nugget based on a preliminary test on the measurement error rather than to fix it based on the experimental variogram.

International audience; Nitrous oxide (N2O) is an important greenhouse gas. Its atmospheric concentration have increased with the industrialisation and the use of N fertilizer. The contribution of freshwater systems to N2O emissions is still very uncertain, while regional transfer of nitrogen depends on soil and hydrology. Riverine and spring N2O dissolved in water was therefore measured over two years in the 3453 km(2) Haut-Loir watershed (France). This temperate cropland watershed is characterized by two different hydrological systems east and west of the Loir River. The eastern rivers, fed by the emergence of the deep Beauce aquifer, exhibited significantly higher dissolved N2O concentrations (Beauce region, mean: 2.93 mu g-N L-1) than the western rivers (Perche region, mean: 0.87 mu g-N L-1), which were largely influenced by runoff during winter flooding. The eastern rivers had large nitrate concentrations all over the year; in the Perche, nitrate underwent a seasonal cycle with large loads during winter floods, but there were no consistent seasonal patterns in N2O. The ratios of N2O in excess of equilibrium on nitrate, often used as a proxy of emission factor (EF), were much smaller than the default IPCC values, both for rivers (0.014% versus 0.25% for IPCC EF5r) and the Loir spring (0.085% versus 0.6% for the IPCC EF5g for groundwater and springs). EF5r were significantly different between the two parts of the watershed only in winter, because of the seasonal variability of NO3-. Moreover dissolved N2O is controlled not only by NO3-, as it is considered in the calculation of the EF5, but also by water pH and dissolved organic carbon. A good prediction of dissolved N2O was obtained using these physicochemical variables and hydrological regions. Thus, these results suggest that the spatial variability of riverine N2O depends on local hydrology, while further research is needed to understand the seasonal variability. (C) 2020 Elsevier B.V. All rights reserved.

International audience

A wide variety of remote sensing and ground-based (proximal sensing) methods have been developed to describe soil physical properties and their lateral variations. Remote sensing enables the estimation of soil properties over large areas, but the information is often limited to the soil surface. Ground-based methods enable the derivation of soil properties for the whole soil column thickness, although these methods cannot be conducted over large areas. The aim of the present study is to contribute to the assessment of the efficacy of airborne thermal prospection over bare soils in soil mapping. This study focuses on a comparison between this technique, which can investigate over the whole soil column thickness after a sufficiently long transient heat exchange period, and pedological and electrical resistivity data that were recorded for three different depths of investigation. The study area is located in the Beauce region, where the soils (haplic Calcisol or calcaric Cambisol) consist of a loamy–clay layer that is 0.3 m–1.4 m thick and overlies Tertiary Beauce limestone. Thermal measurements were recorded by ARIES radiometer in December after six days of heat loss from the ground. The investigation depth could thus be considered to be larger than the thickness of the ploughed layer. Comparisons using statistical analyses between the thermal measurements, electrical resistivity, and pedological data demonstrated that: (i) the spatial organization of the thermal inertia map is similar to the spatial organization of the 0-m to 1.7-m resistivity map; and (ii) the thermal apparent inertia values are significantly different between the haplic Calcisols and the calcaric Cambisols and can thus be mapped with a high spatial resolution over large areas. The applicability of thermal prospecting in soil mapping opens up many possibilities considering the present advances in light-infrared radiometers. Beside agronomical concerns, this methodology will also facilitate progress in engineering applications, including the cross estimation of electrical and thermal properties.

National audience

Impact of anaerobic digestion on n balance in a crop succession fertilized with treated or untreated manures: first results. 20th N Workshop and Side event

In pathological situations such as ischemia-reperfusion and acute respiratory distress syndrome, reactive oxygen species (ROS) are produced by different systems which are involved in endothelial cells injury, ultimately leading to severe organ dysfunctions. The aim of this work was to study the effect of ROS produced by hypoxanthine-xanthine oxidase (Hx-XO) on the adhesion of human umbilical vein endothelial cells (HUVEC) and on the signaling pathways involved. Results show that Hx-XO-derived ROS induced an increase in HUVEC adhesion in the early stages of the process (less than 30 min), followed by a decrease in adhesion in the later stages of the process. Interestingly, Hx-XO-derived ROS induced the same biphasic effect on the phosphorylation of the focal adhesion kinase (FAK), a nonreceptor tyrosine kinase critical for cell adhesion, but not on ERK1/2 phosphorylation. The biphasic effect was not seen with ERK1/2 where a decrease in phosphorylation only was observed. Wortmannin, a PI3-kinase inhibitor, inhibited ROS-induced cell adhesion and FAK phosphorylation. Orthovanadate, a protein tyrosine phosphatase inhibitor, and Resveratrol (Resv), an antioxidant agent, protected FAK and ERK1/2 from dephosphorylation and HUVEC from ROS-induced loss of adhesion. This study shows that ROS could have both stimulatory and inhibitory effects on HUVEC adhesion and FAK phosphorylation and suggests that PI3-kinase and tyrosine phosphatase control these effects.

International audience; Denitrification in riparian wetlands plays a major role in eliminating nitrate coming from agricultural watershed uplands before they reach river water. A new approach was developed for representing this process in the biogeochemical Riverstrahler model, using a single adjustable parameter representing the potential denitrification rate of wetland soils. Applied to the case of three watersheds with contrasting size, land-use and hydro-climatic regime, namely the Seine and the Loir rivers (France) and the Red River (Vietnam), this new model is able to capture the general level of nitrate concentrations as well as their seasonal variations everywhere over the drainage network. The nitrogen budgets calculated from the results show that riparian denitrification eliminates between 10 and 50% of the diffuse sources of nitrogen into the hydrosystem coming from soil nitrate leaching.

The intensification of agriculture has been made possible by increasing the supply of synthetic mineral nitrogen to crops. That has led to increased losses of reactive nitrogen (Nr e.g. ammonia NH3, nitrous oxide N2O, nitrogen oxides NOx, nitrate NO3−, ammonium NH4+) in the environment that may produce negative impacts on agroecosystems: soil, water or air pollution, greenhouse gas emission, biodiversity loss. The nitrogen losses result from a cascade of a large number of processes that interact spatially and temporally in agroecosystems. Integrated models are very useful to investigate such complex systems. We used the NitroScape model that couples an agroecosystem model, a cattle farm model, an atmospheric model of dispersion, transport and deposition, and a hydrological model. It made it possible to simulate processes of the nitrogen cascade at the landscape scale (i.e. a domain from a few square metres to a few tens of square kilometres). The model was applied on an agricultural site of 427 ha in Central France to simulate nitrogen flows for years 2014 and 2015. It used data from measurement campaigns and farm surveys that provided soil characteristics, meteorological data and crop management for the two years of simulation. The simulation results were compared to nitrogen fluxes and concentrations measured in the air, the soil and plants. The simulated Nr fluxes were consistent with the observed fluxes (i.e. low root mean square error, coefficients of regression significant at a 5% level). The coupled NitroScape model that integrates numerous related-nitrogen processes was therefore able to reproduce the main Nr fluxes. However, there were discrepancies between simulated and observed values for N2O emissions resulting from denitrification and for NH3 volatilisation. The model showed that the main Nr losses were due to NO3− leaching, which accounted for 11% of the nitrogen outflows (29 kg N ha−1 yr−1). Total losses of Nr (emissions of NH3, NO and N2O, and NO3− leaching) in the environment accounted for 13% of the nitrogen outflows. Two alternative scenarios aiming at enhancing nitrogen use efficiency and mitigating losses of Nr in the environment were built and assessed with the model. Simulations showed that changing nitrogen fertilisation and including catch crops and buffer strips led to a 18% decrease of NO3− losses. They also showed that including pea in crop rotation led to a 25% decrease of mineral fertilisation and a reduction of NO3− losses of 2 kg N ha−1 yr−1. The NitroScape model is a valuable tool to assess the effect of nitrogen management at the landscape scale on mitigation of nitrogen losses in the environment.

National audience; Dans le cadre du projet ANR Escapade, 4 sites ont été instrumentés pour constituer une base de données nécessaire à la validation des modèles mis en œuvre pour appréhender la cascade de l'Azote à l'échelle des paysages. Outre l'acquisition des flux d'azote vers les hydrosystèmes déjà en place pour la majorité des sites, des équipements nouvellement acquis ont permis de mesurer les flux d'oxyde nitreux (N2O) en fonction de l'occupation des sols et de leurs caractéristiques et de déterminer les concentrations atmosphériques en NH3.Ces données montrent des flux d'azote en général plus élevés pour le Naizin (Bretagne), tant par sa pluviométrie élevée que son système agricole dominé par l'élevage, à la différence des autres sites essentiellement dominés par la grande culture. Les sites des Avenelles (en Brie) et OS2 (en Beauce) présentent des résultats assez semblables. Le régime hydrologique de type semi-aride de l'Auradé introduit plus de la variabilité qu'ailleurs. Au-delà de constituer des données de validation des modèles et de nourrir des bases de données nationales, européennes et mondiales, nécessaires pour alimenter les directives, ces données peuvent servir à la compréhension du fonctionnement de petits territoires grâce à l'établissement de bilans, et ces connaissances par sites peuvent être mises en perspectives pour mieux comprendre les facteurs qui déterminent leurs spécificités (climat, caractéristiques des sols, pratiques agricoles, systèmes, etc.). Les bilans et la modélisation sont ainsi appelés à se nourrir réciproquement.

CT4 ; hors EnjS; International audience; In order to take best advantage of the electrical resistivity data, kriging spatial component technique was applied to separate the small and large-scale structures of resistivity data. Then the spatial structures in resistivity data which are poorly correlated with soil water content are filtered out prior to integrating resistivity data into water content estimation in the soil of a 10 ha area located in the Picardie region (Northern of France). The soil water content was measured until 1.2 m depth in 81 sites with 0.3 m increments by gravimetric method. The resistivity was exhaustively measured for three different depths: 0.5 m, 1 m, and 2 m. The resistivity data represents a set of 5656 measurement points for each of the three depths over the 10 ha study area. The methodology involves successively: (1) a principal component analysis (PCA) on the electrical measurements for the three depths of soil; (2) a geostatistical filtering of the local component and noise in the first component (PC1) of PCA which account for 90% of the variance in the electrical measurements for the three depths of soil. Results have shown that the correlation between water content of soil profile (W) and PC1 is highly improved when the local component and noise were filtered out. Finally, the influence of the smoothness of the external drift function on the quality of estimates of a target variable was empirically demonstrated. Indeed, the estimates of W were highly improved when the external drift function used in kriging is much smoother: the large scale of PC1 instead of PC1.

International audience; Characterizing water processes at the field scale requires an accurate and high-resolution description of the variability of representative state variables, such as water content. Obtaining these data, however, is unrealistic with conventional soil water sensors; we therefore propose an empirical approach to measure water content based on electrical resistivity. This geophysical method provides exhaustive and time-repetitive information on the resistivity of a DC signal. Resistivity can be used to estimate water content, although the interpretation is not straightforward. As the approach is inexpensive and allows for repeated high-resolution measurements, its potential benefits for the monitoring of soil water processes at the field scale warrant greater investigation. Soil electrical resistivity and soil water content were monitored at the field scale on four dates in 2006, by MuCEP (MultiContinous Electrical Profiling), which gives measurements at high spatial resolution, and by precise measurements of soil water content. The spatial organization of soil water dynamics was extrapolated from the geostatistical analysis of the spatial and temporal variability of electrical resistivity, and then improved data were obtained for the whole of the studied area. Homogeneous zones were then delineated and compared with soil units defined on a soil map. We demonstrated that the zones that had less than average soil water content over time for the whole area corresponded to those zones that had greater than average electrical resistivity values over time. The spatial similarity between these zones and the soil units defined on the soil map suggested that water flows were mainly vertical in the field. Nevertheless, our method could be used to characterize some specific hydrodynamic processes, such as lateral flows or upward capillary flows, that are usually difficult to characterize from the information derived from the soil map.

Soil compaction decreases soil aeration and water infiltration, lowering air-filled porosity, which may impact biological processes involved in soil fluxes of carbon dioxide ( F CO2 ) and methane ( F CH4 ), and decrease the greenhouse gas emissions mitigation potential offered by the forestry sector. We recorded F CO2 and F CH4 continuously for two years using automated chambers connected to a laser-based gas analyser in an experimental forest site on an acidic ruptic Luvisol that was established to assess the long-term impact of a loaded forwarder. Heavy machine traffic had considerably increased soil surface roughness. Air-filled porosity ( AFP ) in the first 0.1 m was lower in the trafficked plot – especially in hollows – than in the control almost all year long. The temperature sensitivity of F CO2 was higher for the control plot than for both mounds and hollows in the trafficked plot. Cumulative F CO2 was much higher in the control than in hollows and mounds of the trafficked plot. In contrast, annual F CH4 did not significantly differ between the control plot and either the mounds or the hollows in the trafficked plot, but was significantly higher in mounds than in hollows. F CH4 was negative all year round indicating a net uptake of CH 4 , except during winter when a net emission of CH 4 was occasionally observed in the hollows on the trafficked plot. While seasonal variations of F CH4 were well related to variations in AFP , the potential rate of methane uptake at optimal air-filled porosity was higher in the trafficked plot than in the control.

Among oxygen free radicals, the hydroxyl radical OH° is considered to be the most toxic. It reacts very rapidly with virtually all molecules, leading to the formation of secondary free radicals and finally to oxidized end-products. OH° scavenger molecules protect against OH° toxicity. The aim of this work was to measure the reactivity of pentoxifylline (Ptx) with OH° and to determine its ability to protect a biological target, (lysozyme), from OH° inactivation. Pulse and gamma radiolysis were used respectively to obtain high single and stationary concentrations of OH°. We found that Ptx forms a transient radical with a rate constant of 7 X 109 M−1 s−1 and that this one disappears with a half-life of 25 µs. Lysozyme was inactivated by OH°, but was protected when Ptx was added to the solution. In comparison with other known scavengers, the following order of protection was obtained: thymine

It has been suggested that activation of neutrophils and the complement system plays a role in post-ischemic myocardial dysfunction and restenosis after coronary angioplasty. Furthermore, recent experimental evidence suggests activation of the neutrophils in angina pectoris and acute myocardial infarction. Percutaneous transluminal coronary angioplasty (PICA) represents both a controlled injury to the coronary arterial wall, and a model of transient ischemia. Both of these processes are liable to activate neutrophils.The aim of this study was to investigate ex vivo the morphological and functional characteristics of coronary sinus neutrophils, before and immediately after PTCA. Neutrophil activation was assessed by 1.measurement of plasma lactoferrin (LF) and plasma myeloperoxidase, to study release of specific and azurophilic granules respectively, 2.whole blood chemiluminescence stimulated in vitro by phorbol-myristate acetate and opsonized zymosan, 3.plasma fluorescent thiobarbituric acid-reactive substances (TBA-RS). These measurements were performed in blood drawn from the coronary sinus, before and immediately after PICA (7 Pts). To ensure that changes observed were related to PTCA but not to the catheterization procedure, controls undergoing coronary angiography without PICA were also studied. (4 Pts).After PTCA, LF increased 2 fold (p

Reactive oxygen species (ROS) are now well known to be involved in an increased interaction between neutrophils and endothelial cells. Previously, we have shown that the increased adhesion of neutrophils to ROS-stimulated endothelial cells involves an increase in tyrosine phosphorylation of the focal adhesion kinase, p125 FAK , and several cytoskeleton proteins. This review article focuses on the involvement of adhesion molecules in the increased adhesion of neutrophils to ROS-stimulated endothelial cells, on the oxygen species responsible for this adhesion, and on the intracellular signaling pathway leading to the modification of the cytoskeleton by ROS. The evidence from our laboratory and others describing these events is summarized. Finally, the future perspectives that need to be explored in order to inhibit or reduce the ROS-mediated adhesion of neutrophils to endothelial cells are addressed.

Hydroxytyrosol (HT) (also known as dihydroxyphenylethanol (DPE)) is a polyphenol extracted from virgin olive oil. HT is known to exert an antioxidant effect but the mechanism of action and the identity of the reactive oxygen molecule(s) targeted are not known. In this study, we show that HT inhibits luminol-amplified chemiluminescence of human neutrophils stimulated with N-formyl-methionyl-leucyl-phenylalanine (fMLP), phorbol myristate acetate (PMA) and opsonized zymosan. This effect was dose-dependent and occurred immediately after the addition of HT. However, HT had no effect on lucigenin-amplified chemiluminescence, suggesting that it does not inhibit NADPH oxidase activation or scavenge superoxide anions. Furthermore, HT inhibited H(2)O(2)-dependent-dichlorofuoroscein (DCFH) fluorescence of activated neutrophils, as measured by flow cytometry. Finally, HT inhibited luminol-amplified chemiluminescence in a cell-free system consisting of H(2)O(2) and HRPO. These results suggest that HT, a polyphenol derived from olive oil, could exert its antioxidant effect by scavenging hydrogen peroxide but not superoxide anion released during the respiratory burst.

It was recently shown that vascular endothelial growth factor (VEGF), a growth factor for endothelial cells, plays a pivotal role in rheumatoid arthritis. VEGF binds to specific receptors, known as VEGF-RI and VEGF-RII. We assessed the physical and histological effects of selective blockade of VEGF and its receptors in transgenic K/BxN mice, a model of rheumatoid arthritis very close to the human disease. Mice were treated with anti-mouse VEGF Ab, anti-mouse VEGF-RI and -RII Abs, and an inhibitor of VEGF-RI tyrosine kinase. Disease activity was monitored using clinical indexes and by histological examination. We found that synovial cells from arthritic joints express VEGF, VEGF-RI, and VEGF-RII. Treatment with anti-VEGF-RI strongly attenuated the disease throughout the study period, while anti-VEGF only transiently delayed disease onset. Treatment with anti-VEGF-RII had no effect. Anti-VEGF-RI reduced the intensity of clinical manifestations and, based on qualitative and semiquantitative histological analyses, prevented joint damage. Treatment with a VEGF-RI tyrosine kinase inhibitor almost abolished the disease. These results show that VEGF is a key factor in pannus development, acting through the VEGF-RI pathway. The observation that in vivo administration of specific inhibitors targeting the VEGF-RI pathway suppressed arthritis and prevented bone destruction opens up new possibilities for the treatment of rheumatoid arthritis.

Two-phase sampling design with a covariate gives an unbiased mean value at field scale.Various second phase sampling strategies are easily implemented using R software.The precision of the estimates are assessed for the different sampling strategies.Accounting for a covariate in the second phase of the sampling improves the precision. The objective of this paper is to determine the mean value of Available Water Capacity (AWC) of a soil at field scale in the context of improving the water use efficiency in agriculture. The reasoning in this work consists in determining the minimum number of locations where AWC has to be measured in a 9ha field, using different two-phase sampling strategies, to obtain a mean AWC with an adequate precision. First, 44 locations spaced on a regular square grid were chosen by a systematic random sampling (first phase of the sampling). AWC and Soil Electric Resistivity (SER) were estimated at each location. The 44 locations were then subsampled using four sampling methods and by considering subsets of various sizes, from 1 to 10 (second phase of the sampling). For each combination involving one sampling method and one subset size, 10,000 subsets were generated independently. Each subset was used to estimate one value of the mean of AWC for the field and thus, the average value for the means of the 10,000 subsets. For each combination, we computed the range L of the interval containing 95% of the 10,000 estimated means. As the more precise, the smaller L was the correct estimation for the corresponding combination. One sampling method for the second phase was the simple random sampling, and the three other used the SER as a covariate. The latter led to more precise estimates of the mean AWC than the simple random sampling. A threshold of 30mm, corresponding to one irrigation period in the study area was chosen as the minimum precision required. This threshold was not exceeded for a subset of 5 locations in the cases of sampling methods accounting for the SER as a covariate whereas 8 locations were required for the sampling method that ignores covariate.

Objective—Activated polymorphonuclear neutrophils (PMNs) are the main source of circulating neutral endopeptidase (NEP). We tested the hypothesis that NEP inhibition could potentiate the effect of atrial natriuretic peptide (ANP) on PMN-vascular cell interactions in vitro.Methods and Results—ANP alone and its potentiation by retrothiorphan, the NEP inhibitor, significantly inhibited superoxide, lysozyme, and matrix metalloproteinase (MMP)-9 release byN-formyl-Met-Leu-Phe-stimulated PMNs. Activated PMNs degraded exogenous ANP, which was prevented by NEP inhibition. Hypoxia significantly increased the adhesion of PMNs to endothelial cells and their subsequent MMP-9 release by 60% and 150%, respectively (PPN-formyl-Met-Leu-Phe-stimulated PMNs exhibited morphological and biochemical changes characteristic of apoptosis (terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling positivity, nuclear condensation/fragmentation, poly ADP-ribose polymerase cleavage, and DNA laddering). SMC detachment and subsequent apoptosis could be related to leukocyte elastase-induced pericellular proteolysis, inasmuch as both events are inhibited by elastase inhibitors. ANP and its potentiation by retrothiorphan were able to limit elastase release, fibronectin degradation, and SMC apoptosis.Conclusions—ANP potentiation by NEP inhibition could limit PMN activation and its consequences on vascular cells.

Objective Reactive oxygen species are thought to play a role in rheumatoid arthritis (RA) in humans. We postulated that antioxidant treatment could have a beneficial effect in this disease. We therefore investigated the effects of vitamin E in the transgenic KRN/NOD mouse model of RA. Methods Mice were treated by gavage with oral vitamin E (α-tocopherol). Clinical, histologic, and biochemical parameters were assessed for 6 weeks. Results Vitamin E treatment did not modify the clinical features of the disease (date of onset or disease intensity, as measured by the articular index), but it did prevent joint destruction, as measured by qualitative and semiquantitative analyses. Redox status did not differ between treated and control mice. White blood cell chemiluminescence was higher in transgenic KRN/NOD mice than in controls, but vitamin E treatment attenuated this difference. Vitamin E treatment of the transgenic animals led to a significant decrease in the levels of interleukin-1β (IL-1β) but not tumor necrosis factor α. Conclusion Vitamin E seems to uncouple joint inflammation and joint destruction in this model of RA, with a beneficial effect on joint destruction. Since many investigations are currently in progress to evaluate the benefit of interventions targeted toward anti-IL-1β, our findings suggest opportunities of therapeutic interest in human RA.

International audience; This paper investigates how the spatial correlations between topographic attributes and a soil thickness can be improved by focusing on the relationships between them at specific spatial scales. In addition, this paper examines the effects of the topographic attribute data sources that are used as explanatory variables for modeling the response variable, and considers the possibility of model extrapolation for mapping beyond the area where the model was established. Here, factorial kriging analysis (FKA) and partial least square regression (PLSR) analysis are used to separate nuggets and small- and large-scale structures in data including four topographic attributes and soil thickness (ST). These analyses were conducted at different scales to analyze the relationships between ST and the selected topographic attributes in the southwest region of the Parisian Basin. The structural correlation coefficients from the FKA show strong correlations between the variables. These correlations, which change as a function of spatial scale, are not revealed by the linear correlation coefficients. The Eigen vectors from the principal component analysis that was performed on the small-scale and large-scale structures of the linear co-regionalization model are used to obtain ST and the topographic attributes at both spatial scales over the study area. The ST models are built as a function of topographic attributes using PLSR. Results have shown that the models built using variables that were assessed at a specific scale are better at predicting the target variable than models that were built using raw data. Regarding the models that were built using raw data, the structural correlations that occur at different spatial scales are merged together and the variance–covariance matrix of the nugget that represents data noise is not filtered out. Measures of model performance that are based on a validation data set have shown that the model based on small-scale structure (Model-S) is better for predicting soil thickness than the model based on large-scale structure (Model-L). The effects of topographic attribute data sources as explanatory variables for modeling ST are less significant than the effects of the two models for mapping. Moreover, extrapolation of themodel-S beyond the areawhere it was generated is appropriate. The decomposition process is associated with a modeling approach, such as the PLSR, which accounts for the collinearity between predictor variables and leads to an efficient prediction model. These results are important for modeling soil properties based on topographic attributes and for spatially generalizing models that have been established over small to large areas. Thus, in the presence of nested variogram models, the correlations between variables of interest and auxiliary information should be improved by filtering out some of the spatial structures by factorial kriging. The information filtered is associated with an appropriate approach for modeling when collinearity occurs between the predictor variables and provides a suitable model for predicting and spatially generalizing a locally established model.

Objective In addition to lowering lipid levels, statins might reduce leukocyte-endothelial cell interactions. Therefore, we assessed whether this effect could limit the inflammatory response to cardiopulmonary bypass (CPB) in cardiac surgical patients. Methods Twenty patients undergoing valve or coronary operations with tepid (34 degrees C) CPB were randomized to receive an oral dose of atorvastatin (40 mg the evening before and 40 mg the morning of surgery) or to serve as controls. Pre- and post-CPB blood samples were assayed for neutrophil CD11b surface adhesion molecule and oxidative burst. Plasma levels of interleukins 6 and 8, P-selectin, soluble intercellular adhesion molecule-1, and lactoferrin were measured by enzyme-linked immunosorbent assay (ELISA). In addition, right atrial biopsies were taken before and at the end of CPB, and processed for the expression of the transcription nuclear factor-kappa B (NF-kappaB). Results The two groups did not differ with regard to pre- and intraoperative data. Except for P-selectin, postbypass values of all markers significantly increased over baseline values, but atorvastatin therapy failed to attenuate the magnitude of this increase. In the two groups, the expression of NF-kappaB significantly (p = 0.004) increased over baseline without group effect. Postoperative clinical outcomes did not differ either between the two groups. Conclusion These data show that acute preoperative statin therapy fails to limit the inflammatory response to CPB; however, the data also document a major upregulation of NF-kappaB during cardiac operations, thereby providing a sound rationale for interventions targeted at inactivating this key component of the inflammatory cascade.

SUMMARYNumerous studies suggest that C-ANCA are directly pathogenic in vasculitis by activating leucocytes (oxidative burst, enzyme release, endothelial cytotoxicity, etc.). We and others have shown that C-ANCA can also directly activate HUVEC, but the precise target on HUVEC is unknown. We show in this study that C-ANCA recognize various targets on the HUVEC membrane (different from PR3 in our model), leading to secondary cell activation. Polyclonal affinity-purified C-ANCA recognized targets on the unfixed endothelial membrane in fluorescent ELISA, flow cytometry, and immunoprecipitation studies. C-ANCA did not react with Fcγ receptors. Reverse transcriptase-polymerase chain reaction (RT-PCR) experiments showed that HUVEC did not express PR3. The targets of polyclonal and monoclonal anti-PR3 antibodies on the endothelial membrane were not the same. Some epitopes were lost after trypsin–EDTA digestion and formaldehyde fixation of cells, whereas anti-PR3 targeted unfixed HUVEC. This suggests that anti-PR3 react with the endothelial membrane and recognize conformational epitopes shared with PR3. Endothelial cells may thus participate in the inflammation associated with Wegener's granulomatosis and contribute to the emergence of clinical manifestations.

We investigated reactive oxygen species (ROS) involvement in polymorphonuclear neutrophilic leukocyte (neutrophil) apoptosis triggering. Neutrophils were incubated with xanthine oxidase (XO), which produces superoxide anion (O2.-) and hydrogen peroxide (H2O2) or glucose oxidase (GO), which produces only H2O2. Both XO and GO accelerated apoptosis when compared to spontaneously aged neutrophils. Catalase inhibited both spontaneous apoptosis and XO- or GO-accelerated apoptosis, but superoxide dismutase did not. Hydrogen peroxide can enter the cell, thus generating intracellular oxidation, which was observed by flow cytometry. Furthermore, the intracellular reduced glutathione content fell in the presence of XO or GO; however, apoptosis was not accelerated in the presence of buthionine sulfoximine (BSO), suggesting that the fall in glutathione in the presence of XO or GO is a consequence of oxidative stress but not a trigger of apoptosis. Hydrogen peroxide can react with iron to form hydroxyl radicals (HO.); we observed that two iron chelators, deferoxamine and hydroxybenzyl ethylenediamine (HBED), both inhibited spontaneous and accelerated apoptosis, suggesting that HO. may mediate neutrophil apoptosis.

We investigated the role of intercellular adhesion molecule-1 (ICAM-1) in the adhesion of polymorphonuclear neutrophils (PMN) to classic antineutrophil cytoplasmic antibody (C-ANCA)-treated endothelial cells, independently of cytokines. Human umbilical vein endothelial cells (HUVEC) grown to confluence in cytokine-free conditions were stimulated with C-ANCA sera and affinity-purified anti-proteinase 3 antibodies (PR3) from Wegener's granulomatosis (WG) patients. Non-activated PMN were added to treated HUVEC and adhesion was measured. In parallel experiments, treated HUVEC were fixed and ICAM-I and E-selectin were assayed by cyto-ELISA; in other experiments anti-ELAM-1 and anti-ICAM-1 antibodies were assessed. In this in vitro model, adhesion of non-activated PMN to anti-PR3-stimulated HUVEC was enhanced. Adhesion was greater with anti-PR3 antibodies than with control and normal immunoglobulins, and correlated with the level of anti-PR3 antibodies. Neutralization of anti-PR3 antibodies by neutrophil azurophilic granule proteins abolished adhesion. This adhesion increased at the fourth hour after simulation, peaked at the twelfth hour and then decreased. This phenomenon occurred mainly through endothelial expression of ICAM-I (the main counter-receptor for integrins, involved in firm PMN adhesion and migration) and E-selectin on HUVEC membranes. Anti-adhesion molecule antibodies inhibited this adhesion. This work supports the hypothesis of a direct effect of C-ANCA in endothelial stimulation, namely, on endothelium--PMN adhesion, and strengthens the major role of ICAM-I, directly involved in firm sticking of PMN to HUVEC, besides E-selectin. C-ANCA upregulate endothelial adhesiveness and thus participate in inflammatory reactions by providing endothelial adhesive structures for neutrophils. This might be one of the first steps leading to clinical expression of the disease. These results provide new insights into the pathogenesis of C-ANCA-related diseases.

Hydrogen peroxide (H2O2) increases adherence of human polymorphonuclear neutrophils (PMN) to cultured human umbilical vein endothelial cells (HUVEC). Catalase and HO. scavengers did not affect the increased PMN adherence to HUVEC stimulated by other compounds such as phorbol myristate acetate (PMA) and thrombin, showing that the observed effect was H2O2- and HO.-specific. This effect was inhibited by hydroxyl radicals (HO.) scavengers and not by iron-chelators that do not penetrate the cells, suggesting the involvement of intracellular HO. in the increased adherence mechanism. An increase in cAMP inhibited H2O2-induced adherence, as observed with isoproterenol, isobutylmethylxanthine, and dibutyryl-cAMP. Similarly, pentoxifylline (Ptx), an HO. scavenger that also increases cAMP, inhibited H2O2-mediated adherence but had no effect on that induced by PMA or thrombin. PKA inhibitors cancelled the Ptx-induced inhibition of H2O2-mediated adherence. However, PKA inhibitors or atrial natriuretic peptide that decreases cAMP did not increase adherence, showing that decrease in cAMP is not responsible for increased adherence. HO. scavengers did not alter the H2O2-induced reduction in cAMP levels, but did inhibit the effect of H2O2 on adherence. We conclude that HO. mediates the H2O2-induced increased in PMN adherence to HUVEC, and that the increase in cAMP that mediates PKA activation downregulates this effect.

Cette synthèse est issue d'un ouvrage édité par le Groupement d'Intérêt Scientifique sur les Sols : Gis Sol. 2011. L'état des sols de France. 188 p.; absent

Cultured human umbilical vein endothelial cells (HUVECs) treated with reactive oxygen species (ROS) show increased adherence of polymorphonuclear leukocytes (PMNs). Because pentoxifylline (PTX) is known to inhibit cell interactions, we studied PMN adherence to ROS-stimulated HUVECs pretreated with PTX. ROS were generated by the oxidation of hypoxanthine by xanthine oxidase, giving rise to superoxide anion and hydrogen peroxide. Human PMNs were then added to HUVEC monolayers. After various times, the cultures were washed and the number of adherent PMNs was estimated by measuring myeloperoxidase in the total cell homogenate. PTX inhibited adherence in a concentration-dependent manner. Moreover, the increase in intracellular cAMP content varied with the PTX concentration. Isobutylmethylxanthine (IBMX) and isoproterenol (ISO), which increase intracellular cAMP content, also inhibited the adherence of PMNs to ROS-stimulated HUVECs. We conclude that cAMP is probably involved in the intracellular regulation of ROS-mediated PMN adherence to endothelial cells.

International audience; Analysing the properties and functional characteristics of heterogeneous soils containing several phases requires a correct estimation of the volume proportion of each phase. In the case of stony soils, the volume percentage of the content of rock fragments remains difficult to estimate in situ. This paper presents a method that uses field spatial electrical resistivity measurements to determine the volume proportion of rock fragments. Based on the hypothesis that the electrical resistivity signal noise increases as the proportion of rock fragments increases, a model was developed that uses the standard deviation of the apparent electrical resistivity measurements over a small area as an indicator of rock fragment contents. The model was tested on three study areas of several hectares containing soil units with varying quantities of rock fragments. The estimation of the rock fragment content was accurate, and the error estimation of about 6 % was the same order of magnitude as the Bussian model (1983). The developed model strongly depends on the water content in the soil and the rock type and must be calibrated in each context. Nevertheless, estimations of the rock fragment content in stony soils can be performed efficiently in the surface horizon as well as all along the soil profile.

We compared the attack of deoxyribose and mannitol by (OH). produced by gamma radiolysis or the iron-driven Fenton reaction. Deoxyribose (DR) oxidation by gamma radiolysis gave rise to thiobarbituric reactive substances (TBARS) with a yield of 17 mol (OH). per mole of TBARS. (OH). scavengers (benzoate, formate, and pentoxifylline) protected DR from oxidation. Mannitol was similarly oxidized by (OH). produced by gamma radiolysis, with a yield of 14 mol (OH). per mole of TBARS produced. A mixture containing both DR and mannitol gave rise to TBARS production with a yield of 9 mol (OH). per mole of TBARS superior to that of each product separately, suggesting the formation of secondary radicals responsible for the degradation of DR or mannitol. When (OH). was produced by the iron-driven Fenton reaction, DR gave rise to TBARS whereas mannitol did not. Furthermore, mannitol protected DR against degradation, apparently in the same way as desferrioxamine and diethylenetriaminepentaacetic acid, suggesting that it acts as an iron chelator. It can thus be assumed that, according to the site of (OH). production, sugar molecules are degraded as a function of their rate constant with (OH). or their iron chelating capacity.

Cet ouvrage a fait l'objet d'une synthèse éditée par le Groupement d'Intérêt Scientifique sur les Sols : Gis Sol. 2011. Synthèse sur l'état des sols de France. 24 p.; absent

The hydroxyl radical (OH.) is a highly-damaging reactive oxygen species, given its high reactivity and the consequent generation of secondary free radicals. This study was aimed at determining the qualitative and quantitative aspects of OH. scavenging by pentoxifylline (Ptx, a methylxanthine), uric acid and thymine on the OH.-induced alterations of a protein, lysozyme. Lysozyme was inactivated by OH. with a yield of 6.5 mol OH./mol lysozyme; moreover, SDS-PAGE showed a loss of native lysozyme (14.4 kDa), the presence of dimer and trimer aggregates and characteristic fragmentation. Tryptophan fluorescence was lost before aggregation became detectable in terms of bityrosine formation. Increasing concentrations of OH. scavengers gave increasing protection of lysozyme activity. Although all three compounds scavenge OH. with high rate constants, their effects were different: uric acid and Ptx prevented aggregation and preserved enzyme activity, whereas thymine preserved activity but did not prevent aggregation. These differences appear to be related to the formation of reducing secondary radicals, underlining the importance of this mechanism in the effects of scavengers.

A new megathrombocytopenic syndrome with giant platelets in peripheral blood and severe thrombocytopenia was diagnosed in a 4-month-old boy. His clinical course included repeated hemorrhagic incidents leading to death at age 37 months. Bone marrow ultrastructural analysis revealed numerous dystrophic megakaryocytes with giant membrane complexes. Although these features were similar to those described for megakaryocytes in mice lacking the gene for transcription factor p45-NF-E2, no abnormalities in the p45-NF-E2 gene could be documented. Platelet membrane analysis showed a reduction in glycoprotein (GP) Ib, but normal content of GPIIb and GPIIIa. Analysis of genes encoding for GPIb alpha and beta, GPV, and GPIX ruled out the possibility that the observed platelet abnormality is a variant of Bernard-Soulier syndrome. A moderate neutropenia was associated with a complete lack of expression of sialyl-Lewis-X on the surface of polymorphonuclear neutrophils. A common defect in posttranslational modification of glycoproteins could account for the diverse cellular abnormalities.

A comité de lecture, avec review; International audience; Recently, geophysical methods have been developed that can monitor soil characteristics spatially at high resolution. However, interpreting electrical measurements is difficult because geophysical data can be influenced by many soil variables, some of which vary over time. Our objective here was to use spatial measurements of electrical resistivity to define zones of homogeneity, to interpret them in terms of changing water contents, and to compare them with a soil map. Our underlying assumption was that the time variation of electrical resistivity at the field scale was only due to the dynamics of soil moisture in our studied field. Monitoring of soil electrical resistivity and soil moisture was performed at four dates during 2006 by two methods: by the use of the MUCEP (MultiContinuous Electrical Profiling) device, which gives measurements over a whole field, and by local gravimetric measurement of soil water content. Homogeneous zones were defined directly from measurements of the electrical resistivity and after ordinary kriging of the water content. Our analysis of spatial and temporal variability has permitted us to discriminate three temporally homogeneous zones, in terms of both electrical resistivity and water content, which were broadly related to the soil map. The use of electrical measurements enabled us to directly describe spatial and temporal changes in soil water content at the field scale and to describe some hydraulic processes, like lateral flows or upward capillary flows, that would be difficult to derive from soil maps.

We have previously reported that K562, a chronic myelogenous leukemia cell line, releases a low molecular weight factor (6 to 8 Kd) that inhibits human polymorphonuclear neutrophil (PMN) adherence and adherence-related functions tested in vitro. We now report that this factor, which we have named K562 inhibitory factor (K562-IF), has potent anti-inflammatory activity in mice, associated with an inhibition of PMN functions. Its in vitro actions were less marked with mouse PMN than with human PMN. They included (1) an inhibition of both nonstimulated locomotion and locomotion induced by FMLP or serum; (2) an inhibition of the chemiluminescence induced by opsonized zymosan, but not that induced by phorbol myristate acetate or FMLP; (3) an inhibition of the degranulation stimulated by opsonized zymosan, as reflected by lactoferrin and lysozyme release; and (4) a decrease in arachidonic acid release and leukotriene B4 production by A23187- stimulated PMN. The in vivo actions of K562-IF after intraperitoneal injection included (1) an inhibition of subcutaneous PMN accumulation at the site of injection of opsonized zymosan (PMN accumulated neither outside the vessels nor intravascularly, as shown by means of histochemistry); (2) an inhibition of neutrophil accumulation in the peritoneum of mice having received sodium caseinate or opsonized zymosan intraperitoneally; and (3) lysozyme concentration in neutrophils having reached the peritoneum after opsonized zymosan treatment equal to that in blood, suggesting diminished release. PMN influx and degranulation in the peritoneum were reduced by 50% after 3 hours of treatment with 1 microgram of K562-IF (equivalent to the effect of 120 micrograms of prednisolone). Taken together, these results show that K562-IF is a potent anti-inflammatory agent that acts by inhibiting PMN functions.

We evaluated the effects of sublethal Escherichia coli endotoxemia with or without concomitant administration of N-acetylcysteine, an antioxidant agent, on diaphragmatic strength, endurance, and malondialdehyde (MDA) content in rats. One hundred ninety rats were inoculated subcutaneously on 2 successive days with 0.6 and 1.2 mg/100 g body weight of E. coli lipopolysaccharide respectively (E animals, n = 100) or saline (C group, n = 90). E and C animals were divided into two groups based on administration of endotoxin or saline alone (E group, n = 55; C group, n = 47, respectively) or endotoxin or saline plus N-acetylcysteine (1 g/kg body weight/day intraperitoneally) (E-NAC group, n = 45; C-NAC group, n = 43, respectively). Diaphragmatic strength was assessed in vivo 48 h after the first endotoxin or saline administration by measuring the transdiaphragmatic pressure (Pdl) generated during electrical stimulation of the phrenic nerves at 0.5, 10, 20, 30, 50, and 100 Hz. Endurance index was calculated as the percent ratio of Pdl generated after 30 s of phrenic stimulation at 10 Hz divided by the initial force. Diaphragmatic MDA (fluorometric technique) was measured 0, 6, 18, 30, 42, and 48 h after the first dose of endotoxin or saline. Pdl for 50 and 100 Hz was significantly reduced in Group E as compared with group C. This phenomenon was associated with a reduced endurance performance as assessed by a lower diaphragmatic endurance index in E as compared with C animals (90.9 +/- 4.2 versus 114.3 +/- 4.1 respectively; p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

The aim of this article is to present a strategy to interpret the hydraulic functioning of a small field area by using measurements of the soil electrical resistivity. The spatial soil electrical resistivity was recorded at a high resolution on a 2ha area by the MultiContinous Electrical Profiling (MuCEP) device at two dates. These apparent electrical resistivity measurements were firstly interpreted in terms of local electrical resistivity by 1D inverse modelling to estimate the real resistivity of the soil. These interpreted electrical resistivity data were then transformed into soil water content values and soil water potential values by the use of independent punctual data of water content and the use of the water retention curve determined by laboratory data. Our analysis has permitted us to describe the spatial variability and temporal evolution of the hydraulic functioning at high resolution from electrical resistivity data. The interpretation of the water content and matric potential maps demonstrated that some soil hydraulic processes, such as lateral overland flow, can occur in the studied zone. They would never have been detected by local measurements of soil characteristics or by the use of the soil map., Ces travaux ont pour objectif de proposer une stratégie permettant de discuter du fonctionnement hydrodynamique des sols à l’échelle parcellaire, à partir de mesures spatiales de la résistivité électrique. Celle-ci a été mesurée à deux dates, sur une parcelle de 2ha, à l’aide du MultiContinous Electrical Profiling (MuCEP). Ces mesures électriques ont été analysées localement par un modèle 1D, de façon à estimer la résistivité vraie du sol, puis les données de résistivité vraie ont été interprétées en termes de teneur en eau et de potentiel matriciel, à l’aide de mesures ponctuelles de teneur en eau et de la courbe de rétention des sols étudiés, déterminée de façon indépendante au laboratoire. Cette analyse a permis de décrire la distribution spatiale et l’évolution temporelle de la teneur en eau du sol à haute résolution. L’interprétation des cartes de teneur en eau et de potentiel matriciel met en évidence certains processus hydrodynamiques, tels que des écoulements latéraux hypodermiques. Ceux-ci n’auraient pu être détectés par des mesures ponctuelles de teneur en eau et n’auraient pu être inférés à partir de la carte des sols de la parcelle.

Pentoxifylline (Ptx) is a tri-substituted purine with anti-inflammatory properties which are thought to be due, in part, to oxygen radical scavenging. This paper reports an investigation of the reaction of Ptx with the hydroxyl radical [OH.], superoxide anion, azide radical and hydrogen peroxide generated by pulse and gamma-radiolysis, which was carried out to determine the scavenging properties of Ptx towards oxygen radicals. The superoxide anion, azide radical and hydrogen peroxide did not react with Ptx, whereas OH. reacted rapidly. In gamma-radiolysis, the action of OH. on Ptx at pH 7.4 gave rise to an end-product separated by high-performance liquid chromatography and identified by nuclear magnetic resonance and mass spectrometry as C-8-OH-Ptx (yield 0.12 x 10(-6) mol J-1). The reaction of Ptx with OH. after pulse radiolysis at pH 7-7.4 occurred with a rate constant of (7.7 +/- 1.0) x 10(9) mol-1 s-1, forming time-dependent transient radicals. The initial spectrum (2 microseconds after the pulse) showed three maxima (310, 338 and 500 nm). A decrease in the absorbance around 500 nm and an increase around 310 nm reflected a first-order reaction, suggesting a unimolecular rearrangement. It was shown by redox titration that at least two OH-adducts were formed, one with reducing and the other with oxidizing properties. These results suggest that the reducing radical may be (C-8-OH-Ptx)(.).

The biological effects of estrogens seem to be divided into three mechanisms of action: (1) the transcriptional action by the estrogen-estrogen receptor (ER) complex, (2) the non-genomic mechanism through ERs in cell membranes, and (3) the ER-independent mechanism. The latter mechanism has been attributed to be mediated by the basic chemical properties of estradiol (E2) metabolites, which seems to include their pro- and anti-oxidant properties. Therefore, in order to study the ER-independent actions of the E2 metabolites, their redox properties must be conserved. In this study, we have developed a test to measure the electron-donating properties of E2 and its metabolites based on the reduction of Cu(II) ion into Cu(I). Our results show that the catechol- and methoxy-metabolites of E2 lose their capability to reduce Cu(II) into Cu(I) after 3 months of storage at -20 degrees C. Thus, we propose this inexpensive and reliable test to verify the electron-donating properties of E2 metabolites in order to study their ER-independent biological effects in vitro.

Background Reactive oxygen species (ROS) are suspected to play a role in human RA. Transient hypoxia and ischaemic-reperfusion phenomenon are involved in their chronic production, by monocytes and macrophages. Nevertheless the clinical interest of ROS scavengers is difficult to evaluate. Objectives Methods We studied the effects of Vitamin E (natural alpha tocopherol) on transgenic KRN/NOD mice, new model for rheumatoid arthritis. We determined clinical, histological and biochemical parameters so as to define the long-term benefit of Vitamin E in the disease. Results We found an increase in plasma Vit E, in treated mice. Vitamin E treatment did not modify the date of onset of the disease, neither the intensity of the disease (arthritic index and weight), but Vit-E prevented from articular destruction, suggesting uncoupling of the two phenomenon. Biochemical analysis, blood glutathion, urine isoprostane and the plasma hydroperoxide did not differ between Vit E-treated transgenic KRN/NOD mice and control mice. Blood chemiluminescence was increased in transgenic KRN/NOD mice as compared to non-transgenic mice, and was decreased in Vit E-treated transgenic KRN/NOD mice. TNF-a and IL1-b, low in control non-transgenic mice, were increased in transgenic KRN/NOD mice, however a significant decreased in IL-1b appeared in Vit E-treated mice. Conclusion These results suggest that ROS scavengers can modulate cytokines responses and provide new arguments for the interest of ROS scavengers in RA therapy.