Green Edge ice camp campaigns : understanding the processes controlling the under-ice Arctic phytoplankton spring bloom

The Green Edge initiative was developed to investigate the processes controlling the primary productivity and fate of organic matter produced during the Arctic phytoplankton spring bloom (PSB) and to determine its role in the ecosystem. Two field campaigns were conducted in 2015 and 2016 at an ice camp located on landfast sea ice southeast of Qikiqtarjuaq Island in Baffin Bay (67.4797∘ N, 63.7895∘ W). During both expeditions, a large suite of physical, chemical and biological variables was measured beneath a consolidated sea-ice cover from the surface to the bottom (at 360 m depth) to better understand the factors driving the PSB. Key variables, such as conservative temperature, absolute salinity, radiance, irradiance, nutrient concentrations, chlorophyll a concentration, bacteria, phytoplankton and zooplankton abundance and taxonomy, and carbon stocks and fluxes were routinely measured at the ice camp. Meteorological and snow-relevant variables were also monitored. Here, we present the results of a joint effort to tidy and standardize the collected datasets, which will facilitate their reuse in other Arctic studies

A simplified and accurate method for the analysis of urinary metabolites of testosterone-related steroids using gas chromatography/combustion/isotope ratio mass spectrometry.

International audienceThe analysis of urinary metabolites of testosterone-related steroids through the measurement of their carbon isotopic signature (δ(13) C) by gas chromatography/combustion/mass spectrometry (GC/C/IRMS) is a confirmation method employed in doping control analyses. Stringent analytical conditions are essential to an accurate and precise analysis as well as the proper selection of the metabolites, which forms the basis of the refined method presented in this paper. In a simplified approach, following enzymatic hydrolysis and extraction from a relatively low volume of urine sample, a one-step high-performance liquid chromatography (HPLC) purification was developed for seven diagnostic urinary metabolites (TS) including testosterone itself, dehydroepiandrosterone, 5α- and 5β-androstanediol, epitestosterone, androsterone, etiocholanolone and two endogenous reference compounds (ERC), 5β-pregnanediol and 5α-androst-16-en-3β-ol. These steroids were pooled in three fractions and analyzed as such. With regards to the GC/C/IRMS analysis, a multi-level isotopic calibration using the 'identical treatment' principle was created. The proposed isotopic calibration yielded results for purified reference steroids with a precision ≤0.15 and accuracy of ≤0.30 ‰ (between-assay, n = 26). Compared to other common endogenous reference compounds, those selected in this study had δ(13) C values close to the target metabolites which, along with the proposed isotopic calibration, produced narrow reference intervals within ± 3‰ for most diagnostic TS-ERC pairs, in compliance with the requirements of the World Anti-Doping Agency. These carefully controlled analytical conditions are compatible with routine operations, affording accurate and precise results for the more diagnostically relevant metabolites such as testosterone itself and the 5α- and 5β-androstanediols. The values of the TS-ERC pairs measured in reference populations are described and the results from the routine testing of several hundreds of athletes' samples are discussed. Robust, this technique permitted the detection of adverse findings that would have been missed had these low level metabolites not been analyzed

Detection of erythropoiesis stimulating agents in urine samples using a capillary Western system

International audienceThe presence of erythropoiesis stimulating agents (ESAs) in the urine samples collected from athletes is detected using traditional Western blotting following either size-based separation (SDS/SAR-PAGE) or isoelectric focusing (IEF). Although there is an important testing effort, there is little doubt that ESAs are still abused in sports and that reducing the costs of the tests might increase the number of tests and improve deterrence. The capillary electrophoresis system developed by Protein Simple may be useful to this end. This platform is fully automated and could be easily implemented in anti-doping laboratories, which would contribute to the improvement of the overall assay performance and standardization of the method. Such an automated system could be of interest during major sports events, such as the Olympic Games, where a high number of samples needs to be analyzed in a short period of time. From the experiments conducted so far, we conclude that the technique is promising, with the sensitivity and reproducibility needed to screen ESAs in human urine samples

Desialylation improves the detection of recombinant erythropoietins in urine samples analyzed by SDS-PAGE.

International audienceRecombinant erythropoietin (rhEPO) has been misused for over two decades by athletes, mainly but not only in endurance sports. A direct rhEPO detection method in urine by isoelectric focusing (IEF) was introduced in 2000, but the emergence of third-generation erythropoiesis-stimulating agents and so-called biosimilar rhEPOs, together with the sensitivity of human endogenous EPO (huEPO) pattern to enzymatic activities and its modification following short strenuous exercise, prompted the development of a complementary test based on SDS-PAGE analysis. While Mircera and NESP are easily detected with the existing IEF and SDS-PAGE methods, some samples containing both epoetin-α/β and huEPO present profiles that are still difficult to interpret. As doping practices have moved to micro-dosing, these mixed patterns are more frequently observed. We investigated the impact of enzymatic desialylation on the urinary and serum EPO profiles obtained by SDS-PAGE with the aim of improving the separation of the bands in these mixed EPO populations. We observed that the removal with neuraminidase of the sialic acid moieties from the different EPOs studied reduced their apparent molecular weight (MW) and increased the migration distance between huEPO and rhEPO centroids, therefore eliminating the size overlaps between them and improving the detection of rhEPO

Sport nutritional supplements: quality and doping controls

Proceedings of the 1st International Meeting of the congress on nutrition and athletic performance, Edmonton, Alberta, Canada, August 8-11, 2001 - Communication lors du congrès 'Nutrition et performance sportive', Edmonton, 8-11 aout 1551

Standardization of reticulocyte counts in the athlete biological passport.

The percentage of circulating reticulocytes (RET%) is a useful marker of blood doping in the context of the Athlete Biological Passport (ABP). The viability of the ABP depends on the comparability of sample data obtained across multiple laboratories for a given athlete. With the recent introduction of a different technology for the measurement of reticulocytes, the goal of this study was to compare currently employed Sysmex XT/XE analyzers to the recently introduced Sysmex XN analyzer. RET% differences were searched in two independent data sets, the first consisting of 95 369 RET% values coming from 29 laboratories located in five continents as part of routine testing for the ABP, the second from a targeted study involving 510 samples analyzed on both a Sysmex XT and XN analyzers by two different laboratories. A relatively small but significant bias of 0.27 ([0.22-0.35] 95% CI) for the first data set and 0.19% ([0.16-0.22] 95% CI) for the second data set was observed with Sysmex XN analyzers returning higher values than Sysmex XT/XE analyzers. This bias appears constant over most of the range of RET% measured in elite athletes. When RET% values are obtained for the same athlete with different technologies (XT/XE vs XN), an adjustment of RET% emanating from the XT/XE instruments through a decrease of 0.22% within the ABP calculated ranges appears to be sufficient to integrate the results from the two technologies

Green Edge ice camp campaigns: understanding the processes controlling the under-ice Arctic phytoplankton spring bloom

International audienceThe Green Edge initiative was developed to investigate the processes controlling the primary productivity and the fate of organic matter produced during the Arctic phytoplankton spring bloom (PSB) and to determine its role in the ecosystem. Two field campaigns were conducted in 2015 and 2016 at an ice camp located on landfast sea ice southeast of Qikiqtarjuaq Island in Baffin Bay (67.4797N, 63.7895W). During both expeditions, a large suite of physical, chemical and biological variables was measured beneath a consolidated sea ice cover from the surface to the bottom at 360 m depth to better understand the factors driving the PSB. Key variables such as temperature, salinity, radiance, irradiance, nutrient concentrations, chlorophyll-a concentration, bacteria, phytoplankton and zooplankton abundance and taxonomy, carbon stocks and fluxes were routinely measured at the ice camp. Here, we present the results of a joint effort to tidy and standardize the collected data sets that will facilitate their reuse in other Arctic studies. The dataset is available at http://www.seanoe.org/data/00487/59892/ (Massicotte et al., 2019a)