Development of an online SPE–LC–MS-based assay using endogenous substrate for investigation of soluble epoxide hydrolase (sEH) inhibitors

Soluble epoxide hydrolase (sEH) is a promising therapeutic target for the treatment of hypertension, pain, and inflammation-related diseases. In order to enable the development of sEH inhibitors (sEHIs), assays are needed for determination of their potency. Therefore, we developed a new method utilizing an epoxide of arachidonic acid (14(15)-EpETrE) as substrate. Incubation samples were directly injected without purification into an online solid phase extraction (SPE) liquid chromatography electrospray ionization tandem mass spectrometry (LC–ESI–MS–MS) setup allowing a total run time of only 108 s for a full gradient separation. Analytes were extracted from the matrix within 30 s by turbulent flow chromatography. Subsequently, a full gradient separation was carried out on a 50X2.1 mm RP-18 column filled with 1.7 μm core–shell particles. The analytes were detected with high sensitivity by ESI–MS–MS in SRM mode. The substrate 14(15)-EpETrE eluted at a stable retention time of 96 ± 1 s and its sEH hydrolysis product 14,15-DiHETrE at 63 ± 1 s with narrow peak width (full width at half maximum height: 1.5 ± 0.1 s). The analytical performance of the method was excellent, with a limit of detection of 2 fmol on column, a linear range of over three orders of magnitude, and a negligible carry-over of 0.1% for 14,15-DiHETrE. The enzyme assay was carried out in a 96-well plate format, and near perfect sigmoidal dose–response curves were obtained for 12 concentrations of each inhibitor in only 22 min, enabling precise determination of IC50 values. In contrast with other approaches, this method enables quantitative evaluation of potent sEHIs with picomolar potencies because only 33 pmol L−1 sEH were used in the reaction vessel. This was demonstrated by ranking ten compounds by their activity; in the fluorescence method all yielded IC50 ≤ 1 nmol L−1. Comparison of 13 inhibitors with IC50 values >1 nmol L−1 showed a good correlation with the fluorescence method (linear correlation coefficient 0.9, slope 0.95, Spearman’s rho 0.9). For individual compounds, however, up to eightfold differences in potencies between this and the fluorescence method were obtained. Therefore, enzyme assays using natural substrate, as described here, are indispensable for reliable determination of structure–activity relationships for sEH inhibition

Use of agricultural statistics to verify the interannual variability in land surface models: a case study over France with ISBA-A-gs

In order to verify the interannual variability of the above-ground biomass of herbaceous vegetation simulated by the ISBA-A-gs land surface model, within the SUR-FEX modelling platform, French agricultural statistics for C3 crops and grasslands were compared with the simulations for the 1994-2008 period. While excellent correlations are obtained for grasslands, representing the interannual variability of crops is more difficult. It is shown that, the Maximum Available soil Water Capacity (MaxAWC) has a large influence on the correlation between the model and the agricultural statistics. In particular, high values of MaxAWC tend to reduce the impact of the climate interannual variability on the simulated biomass. Also, high values of MaxAWC allow the simulation of a negative trend in biomass production, in relation to a marked warming trend, of about 0.12Kyr(-1) on average, affecting the daily maximum air temperature during the growing period (April-June). This trend is particularly acute in Northern France. The estimates of MaxAWC for C3 crops and grasslands, currently used in SURFEX, are about 129 mm and do not vary much. Therefore, more accurate grid-cell values of this parameter are needed

Possibles consequences of climate changes on forage production in France. II. Some examples of livestock systems.

International audienc

Reliability of chemotherapy preparation processes: Evaluating independent double-checking and computer-assisted gravimetric control.

Background and objectives Centralized chemotherapy preparation units have established systematic strategies to avoid errors. Our work aimed to evaluate the accuracy of manual preparations associated with different control methods. Method A simulation study in an operational setting used phenylephrine and lidocaine as markers. Each operator prepared syringes that were controlled using a different method during each of three sessions (no control, visual double-checking, and gravimetric control). Eight reconstitutions and dilutions were prepared in each session, with variable doses and volumes, using different concentrations of stock solutions. Results were analyzed according to qualitative (choice of stock solution) and quantitative criteria (accurate, <5% deviation from the target concentration; weakly accurate, 5%-10%; inaccurate, 10%-30%; wrong, >30% deviation). Results Eleven operators carried out 19 sessions. No final preparation (n = 438) contained a wrong drug. The protocol involving no control failed to detect 1 of 3 dose errors made and double-checking failed to detect 3 of 7 dose errors. The gravimetric control method detected all 5 out of 5 dose errors. The accuracy of the doses measured was equivalent across the control methods ( p = 0.63 Kruskal-Wallis). The final preparations ranged from 58% to 60% accurate, 25% to 27% weakly accurate, 14% to 17% inaccurate and 0.9% wrong. A high variability was observed between operators. Discussion Gravimetric control was the only method able to detect all dose errors, but it did not improve dose accuracy. A dose accuracy with <5% deviation cannot always be guaranteed using manual production. Automation should be considered in the future

Conséquences possibles des changements climatiques sur la production fourragère en France. II. Exemples de quelques systèmes d’élevage

National audienceClimate change, now an acknowledged fact, affects both forage production levels and forage calendar. Simulated production of grass, alfalfa and maize, obtained using a cultivation model, were merged with the modelled representations of the requirements for 13 types of livestock farming systems. Medium and long-term problems affecting livestock feed resources are presented (scenario A2). Reliance on feed stocks and other types of stocks will be increased, and maize will play a more important role. Decreased summer rainfall will make it very difficult to sustain grassland farming systems. On-site expert knowledge of current and possible practices will help provide technical solutions, and determine the issues for which research and experimentation should be carried further.Les simulations de productions d’herbe, de luzerne et de maïs, obtenues en sortie d’un modèle de culture (cf. le premier article) sont combinées aux représentations modélisées des besoins de 13 types de systèmes d’élevage. Les questions d’alimentation des troupeaux qui se poseront à moyen et long terme (scénario A2) sont présentées : le besoin de stocks et sans doute la place du maïs devraient s’accroître ; les systèmes herbagers seront sans doute très difficiles à maintenir en raison de la réduction des précipitations estivales. La connaissance par des experts de terrain des pratiques présentes et possibles permet d’envisager des solutions techniques et de dégager les questions de recherche et d’expérimentation à privilégier

Conséquences possibles des changements climatiques sur la production fourragère en France: I. Estimation par modélisation et analyse critique

National audienceClimate changes carries a risk but also an advantage for forage production, it influences both forage production levels and forage calendar. The results of a single climate model (Arpege) applied to different scenarios of global economic growth, have helped develop the STIC crop model (ACTA-CC project). This model, combined with a thorough knowledge of present and possible practices, provides useful information. For instance, it can help determine possible changes affecting forage grass, maize and alfalfa crops in the main French forage production regions over determined periods of time in the future (21st century). Methods and results are discussed. A second study will apply these scenarios to different types of animal production.Les changements climatiques, maintenant certains, agissent non seulement sur les niveaux des productions de ressources fourragères, mais aussi sur leurs calendriers. Les résultats de modèles de climat de Météo-France (Arpege), sous divers scénarios d’évolution économique mondiale, ont permis d’alimenter le modèle de culture STICS, dans le cadre d’une étude nommée ACTA-CC. L’utilisation de STICS, combinée à une bonne connaissance des pratiques présentes et possibles, montre les évolutions possibles des productions de graminées fourragères, maïs et luzerne à différentes échéances temporelles du XXI e siècle dans les principales régions fourragères françaises. Méthodes et résultats sont discutés. Un second article appliquera ces évolutions à différents ateliers de production animale

Wipe sampling procedure coupled to LC-MS/MS analysis for the simultaneous determination of 10 cytotoxic drugs on different surfaces.

A simple wipe sampling procedure was developed for the surface contamination determination of ten cytotoxic drugs: cytarabine, gemcitabine, methotrexate, etoposide phosphate, cyclophosphamide, ifosfamide, irinotecan, doxorubicin, epirubicin and vincristine. Wiping was performed using Whatman filter paper on different surfaces such as stainless steel, polypropylene, polystyrol, glass, latex gloves, computer mouse and coated paperboard. Wiping and desorption procedures were investigated: The same solution containing 20% acetonitrile and 0.1% formic acid in water gave the best results. After ultrasonic desorption and then centrifugation, samples were analysed by a validated liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) in selected reaction monitoring mode. The whole analytical strategy from wipe sampling to LC-MS/MS analysis was evaluated to determine quantitative performance. The lowest limit of quantification of 10 ng per wiping sample (i.e. 0.1 ng cm(-2)) was determined for the ten investigated cytotoxic drugs. Relative standard deviation for intermediate precision was always inferior to 20%. As recovery was dependent on the tested surface for each drug, a correction factor was determined and applied for real samples. The method was then successfully applied at the cytotoxic production unit of the Geneva University Hospitals pharmacy

Describing the possible climate changes in France and some examples of their effects on main crops used in livestock systems

The effects of climate change on forage and crop production are an important question for the farmers and more largely for the food security in the world. Estimating the effect of climate change on agricultural production needs the use of two types of tools: a model to estimate changes in national or local climates and an other model using climatic data to estimate the effects on vegetation. In this paper, we will mainly present the effects of climate change on climatic features, the variability of criteria influencing crop production in various regions of France and some possible effects on crops