Passer au contenu principal

Secondary menu

  • Nouvelles
  • Ressources
  • Événements
  • Nous joindre
  • Emplois
  • en
  • ko
Logo de l’AMA et lien vers la page d’accueil

Navigation principale

Secondary menu

  • Nouvelles
  • Ressources
  • Événements
  • Nous joindre
  • Emplois
  • en
  • ko
Qui nous sommes
  • Gouvernance
    • Conseil de fondation
    • Comité exécutif
    • Président
    • Vice-présidente
    • Directeur Général
    • Mouvement olympique
    • Gouvernements
    • Comités spéciaux permanents
    • Comités permanents
    • Groupes consultatifs d'experts
    • Groupes de travail
    • Équipe de direction
  • Plan stratégique
  • Financement
    • Financement privé
  • Bureaux
    • Bureau principal
    • Bureaux régionaux
    • Présidence
Nos activités
  • Le Code mondial antidopage
    • Signataires du Code
    • Devenir signataire
    • Code et Standards internationaux 2027
  • Standards internationaux
  • Conformité et surveillance
    • Mise en œuvre et maintenance de la conformité au Code
    • Programme de supervision de la conformité
    • Audits
    • Procédures d'application pour la conformité
    • Programme des observateurs indépendants
  • Éducation et formation
    • Initiatives éducatives
    • Comité Éducation
    • Les valeurs du sport dans chaque classe
    • À propos d'ADEL
    • Recherche en sciences sociales
    • Plateforme de collaboration pour la recherche en sciences sociales
    • Le programme de soutien aux signataires pour la mise en oeuvre du code
    • Cadre global d’apprentissage et de développement
  • ADAMS
    • Mise en place
    • Modules et applications
  • Renseignements et enquêtes
    • Unité de renseignement
    • Unité des enquêtes
    • Projet antidopage du département Renseignements et enquêtes en Europe
  • Aspects juridiques et confidentialité
    • Jurisprudence
    • Avis de droit et articles juridiques sur le Code
  • Développement de programmes
    • Programme des ONAD
    • Programme des ORAD
    • Analyse comparative pour OAD
  • Science et médecine
    • Laboratoires
    • Recherche scientifique
    • Passeport biologique de l'Athlète
    • Autorisation d'usage à des fins thérapeutiques
    • Liste des interdictions
Sportifs et personnel d’encadrement
  • Liste des interdictions
  • Autorisations d’usage à des fins thérapeutiques
  • Processus antidopage
  • Éducation antidopage
  • Engagement des sportifs
    • Milano Cortina 2026 – Ressources pour les sportifs
    • Engagement des sportifs lors des événements
    • Conseil des sportifs
    • Déclaration des droits antidopage des sportifs
  • Brisez le silence - Signalez le dopage
  • Ombuds antidopage des sportifs
  • Fournir des informations sur la localisation
  • Articles
Partenaires antidopage
  • Comités olympiques et paralympiques
  • Fédérations internationales
  • Organisations nationales antidopage (ONAD)
  • Organisations régionales antidopage (ORAD)
  • Organisations responsables de grandes manifestations
  • Tribunal arbitral du sport
  • Gouvernements
  • Laboratoires
  • Forces de l'ordre
  • Industrie pharmaceutique
  • Fournisseurs de service
  • Financement privé
    • Sword Group
Données et recherche
  • Tendances
  • Statistiques antidopage
  • Recherche scientifique
    • Projets de recherche scientifique
  • Recherche en sciences sociales
    • Projets de recherche en sciences sociales
  • Analyse comparative pour OAD
Médias
  • Nouvelles
  • Rapport annuel 2024
  • Accueil
  • Projets de recherche

Projets de recherche

Passer aux résultats de recherche
Passer aux résultats de recherche
758 résultats
Trier par :
Year approved
758 résultats
Filtres
Retirer tous les filtres
    • Clear selection
    • Selected
    • Plus
    • Clear selection
    • Selected
    • Plus
    • Clear selection
    • Selected
    • Plus
  • Utiliser l'outil de recherche de projets
    • Clear selection
    • Selected
    • Plus
    • Clear selection
    • Selected
    • Plus
    • Clear selection
    • Selected
    • Plus
    • Clear selection
    • Selected
    • Plus
    • Clear selection
    • Selected
    • Plus
    • Clear selection
    • Selected
    • Plus
    • Clear selection
    • Selected
    • Plus
Retirer tous les filtres
10 résultats trouvés.
  • Team dynamics and doping in sport: A risk or a protective factor?

    Team dynamics and doping in sport: A risk or a protective factor?

    By

    Investigateur principal
    P. Dimeo
    Chercheur
    J. Allen
    Chercheur
    J. Taylor
    Chercheur
    S. Dixon
    Chercheur
    L. Robinson

    University of Stirling

    Royaume-Uni   ―   2011   ―   Complété

    Sommaire

     

    Ce document n'est actuellement disponible qu'en anglais.

    Voir le projet à propos de Team dynamics and doping in sport: A risk or a protective factor?
  • AICAR: Determination of AICAR-ribotide in red blood cells as long term marker for an illicit AICAR application

    AICAR: Determination of AICAR-ribotide in red blood cells as long term marker for an illicit AICAR application

    By

    Investigateur principal
    M. Thevis

    German Sport University

    Allemagne   ―   2011   ―   Complété

    Sommaire

    Code: 11C7MT 

    AICAR has been shown to exhibit performance enhancing effects after oral administration due to the stimulation of fat utilization and increased production of mitochondria in laboratory mice after a 4-weeks treatment with AICAR. The drug candidate has not yet received clinical approval and currently undergoes phase-II clinical trials. In urine of healthy humans considerable amounts (up to 7500 ng/mL) were present due to the natural occurrence of AICAR as a (by-) product of purine biosynthesis. Normal (log-transformed) distribution of AICAR excretion into urine was observed, if corrected to creatinine rather than to specific gravity; however, the occurrence of elevated urinary levels (> 3500 ng/mg) after an illicit administration were assumed to last for several hours only, and the detection window offers only limited options for effective doping controls. 
    Circulating AICAR is dedicated to enter the cells with a simultaneous biotransformation from AICAR-riboside to AICAR-ribtotide (phosphorylation at position 5`). This conversion occurs in considerable extent also in erythrocytes. After exposure of erythrocytes to AICAR, the red blood cells contain a significantly elevated amount of AICAR-ribotide and this level is described to be remain stable for approximately 10 days. In the present study it is planned to investigate whether the determination of AICAR-ribotide in red blood cells can serve as potential long-term marker for an illicit AICAR administration. Riboside and ribotide concentrations in plasma and red blood cells of healthy volunteers will be determined by LC-MS/MS and quantified by means of isotope dilution mass spectrometry. Subsequently, reference values will be statistically evaluated. 
    Preliminary experiments have shown that in-vitro experiments (incubating AICAR reference substance in whole blood) induce immediate biotransformation of the riboside to the corresponding ribotide within the erythrocytes. After lysis the elevated ribotide levels can be determined and allow for the development of a pharmacokinetic model for in-vivo conditions.

    Main Findings: 

    AICAR (an adenosine monophosphate-activated protein kinase (AMPK) activator, 5-amino-4-imidazolecarboxyamide ribonucleoside, Acadesine) belongs to the class of metabolic modulators of the WADA Prohibited List and has been banned since 2009 due to its performance-enhancing capabilities. Confiscated products from team managers and anecdotal evidence have outlined the need for adequate test methods, which have been under development from urine in particular. Main issue with this emerging drug is its natural occurrence in every individual at varying concentrations.  
    In the present project, the utility of erythrocytes concerning the detection of AICAR abuse was evaluated. AICAR possesses the ability to penetrate the erythrocyte membrane. After entering the red blood cell cytosol, it is converted into the corresponding phosphate, referred to as AICAR ribotide. Due to the phosphorylation, it is conserved within the erythrocyte and its concentration remains elevated for up to 10 days upon administration of therapeutic amounts of AICAR. Hence, the quantitative analysis of AICAR ribotide levels in erythrocytes was considered as a helpful tool to determine unnaturally high levels. Consequently, an assay employing a stable-isotope labelled internal standard (15N4-AICAR ribotide) was developed to allow for the quantification of the target analyte from 10 μL of erythrocytes. A total of 99 blood samples (49 male and 50 female non-elite athletes) was assayed to establish a reference population-derived ‘normal’ value for AICAR ribotide, which indicates that concentrations higher than 920 ng/mL are not in agreement with naturally circulating AICAR levels. In order to simulate elevated plasma concentrations of AICAR following oral or intravenous administration, in vitro incubations were conducted at 500, 1000, and 10,000 ng/mL in agreement with literature data concerning clinical trials. A rapid uptake of AICAR into the erythrocytes and conversion to the ribotide was observed, yielding concentrations significantly higher than 920 ng/mL within 15 min. Hence, the quantitation of AICAR ribotide in red blood cells derived either from athlete biological passport samples or complementary collected specimens (such as dried blood spots, DBS) can be a viable tool to indicate and eventually prove the illicit intake of AICAR.  

     

    Voir le projet à propos de AICAR: Determination of AICAR-ribotide in red blood cells as long term marker for an illicit AICAR application
  • Application of transcriptional and proteomic profiling to the detection of recombinant human Growth Hormone (rhGH)

    Application of transcriptional and proteomic profiling to the detection of recombinant human Growth Hormone (rhGH)

    By

    Investigateur principal
    B. Gray

    Bond University Limited

    Australie   ―   2011   ―   Complété

    Sommaire

    Code: 11C21BG

    This project seeks to build on the very important findings of a project funded previously by the Australian Government’s Anti-Doping Research Program (ADRP), into the potential application of transcriptional profiles derived from peripheral blood mononuclear cells (PBMCs -lymphocytes & monocytes) for the detection of rhGH. That project identified sets of genes that were consistently either “up” or “down” regulated in mRNA expression, changes that were evident at least 21 days after the final administration of rhGH. The 21 day time period is an extremely important finding given that the current detection “window” with the WADA-approved test for rhGH is only 36 hours (Holt & Sonksen, 2008). The findings of the previous ADRP-funded study clearly provide the foundation for the development of a new, more sensitive test for the detection rhGH, a test with a vastly improved detection “window’. 
    We anticipate that the proposed project will result in the development of a new, more sensitive test for rhGH based on alterations in gene expression assessed at either the transcriptional and/or proteomic level. A cell’s transcriptional “profile” is obtained by measurement of (potentially, genome-wide) genespecific mRNA levels via use of oligonucleotide microarray technology. Subsequent quantitative RT-PCR analyses allow verification of alterations in the expression of candidate genes. A cells “translational”/proteomic profile can be assessed via the techniques of SDS-PAGE and western blotting. These technologies will allow the identification of gene “subsets” whose activity at a specific time-point, is either up-regulated, down-regulated or remains unchanged following a specific intervention. The set of genes responding transcriptionally or translationally to a specific intervention and the temporal extent of such changes potentially provide a set of unique indicators that are characteristic of that intervention. 

    Main Findings: 

    This project has been carried out with the support of The World Anti-Doping Agency. The investigation aimed at pinpointing a set of differentially expressed mRNA genes associated specifically to the uptake of recombinant growth hormone. 
    Particular attentions of this project focused on the determination of exercise related induce gene expression and to compare whether such expression profile shared similarities with rhGH related expression profile. In other words, this project aimed at finding the unique and specific rhGH related gene expression signature eliminating possible additional unrelated expression variables that different types of exercise induce. 
    Three types of exercise regimen (endurance, resistance and anaerobic exercises) were analysed in untrained participants and temporal PBMC extracted cell gene expression profiling using microarray technology was determined for each type of exercise. In addition, mRNA expression profiling was performed on trained individuals carefully sub-grouped in the same types of exercise mentioned previously. 
    Our analysis used a series of state of the art bio-informatics tools aimed at reducing background noise, batch effects between microarrays, false positives and any other un-necessary variables to aim at narrowing the candidate genes at the highest significant relevance to our study and conclusions. 
    The main results obtained in this document are reporting the PBMC’s temporal expression profiling from: I. participants administered with rhGH;
    II. untrained participants undertaking three types of exercise. In addition, non-temporal expression profiling at rest was evaluated on trained participants grouped in the same types of exercise (endurance, resistance and anaerobic).The comparison of all the different profiles has shown that:I. 47 genes are specific to rhGH and unrelated with any of the three exercise related gene expression in untrained individuals.
    II. 2 genes specific to rhGH are seen to be similar to both the Trained and Untrained expression profiles. These two genes consisted of the interferon gamma and the tubulin folding cofactor C.Of note, this two candidate genes were observed specifically in the resistance groups. Finally, these two genes showed fold gene expression levels that are, and across all time points, lower in rhGH related PBMCs than the fold expression values of the resistance groups. 
    The common limitations of this present study are: - Batch effect related to the analysis of the rhGH related study that required the action of the use of a bio-informatic batch effect removal tool.
    - Possible dosage of the rhGH that was administered to reflect a more pronounced expression profile.

    Voir le projet à propos de Application of transcriptional and proteomic profiling to the detection of recombinant human Growth Hormone (rhGH)
  • Carbon Isotope Ratio Determination of Seized Nandrolone, Boldenone and Testosterone

    Carbon Isotope Ratio Determination of Seized Nandrolone, Boldenone and Testosterone

    By

    Investigateur principal
    C. Sagredo

    Oslo University Hospital

    Norvège   ―   2011   ―   Complété

    Sommaire

    Code: 11A26CS

    Determining the origin of anabolic steroids that are also produced endogenously in the human body, is a major issue in doping control. Increasing amounts of anabolic steroid preparations of nandrolone, boldenone and testosterone preparations, both in a ready-to-use form and as bulk material, have been confiscated by the Norwegian Custom Authorities and the Norwegian Police. 
    In rare circumstances, nandrolone and boldenone metabolites may be produced naturally in humans and animals. Hence, the measurement of the 13C‰ value of nandrolone, boldenone and testosterone of synthetic origin is important for their comparison with the nandrolone and boldenone metabolites, and testosterone endogeneously produced. As a result of this, IRMS is required for a definitive assignments of the origin of nandrolone, boldenone and testosterone found in urine. 
    The aim of the project is to determine the 13C/12C ratios of nandrolone, boldenone and testosterone available on the Scandinavian black market. The success of the established doping test is depending on a significant difference in 13C‰ values between the administered product and the endogenously produced steroids. A comprehensive knowledge of these data with a global perspective is essential for doping analysis of certain anabolic-androgenic steroids. 
    In addition, the confiscated testosterone preparations will also be investigated for the content of other possible masking agents like epitestosterone. 

    Main Findings:

    There have been a substantial number of seized doping preparations, including preparations of nandrolone, boldenone and testosterone, in Norway lately. Determining the origin of anabolic androgenic steroids (AAS) that are also produced endogenously in the human body, is a major issue in doping control. The aim of this study was to use GC-C-IRMS to determine the δ13C‰ values of nandrolone, boldenone and testosterone in seized preparations, and to what extent these products have been designed to mimic the endogenous δ13C‰ values, and hence prevent positive GC-C-IRMS findings. Out of 55 products, one nandrolone and five testosterone products (11%) were found to display δC‰ values between -24‰ and -26‰. In addition one nandrolone and eight testosterone products (16%) displayed δC‰ values of -27‰, which is close to the upper reference range (-26‰) reported for urinary reference metabolites. None of the investigated products contained epitestosterone. This study shows that there are AAS available with δC‰ values near and within the endogenous urinary reference range in Norway.

    Voir le projet à propos de Carbon Isotope Ratio Determination of Seized Nandrolone, Boldenone and Testosterone
  • Cardiovascular and central actions of drugs classed as stimulants

    Cardiovascular and central actions of drugs classed as stimulants

    By

    Investigateur principal
    J.R Docherty

    Royal College of Surgeons in Ireland

    Irlande   ―   2011   ―   Complété

    Sommaire

    Code: 11D3JD 

    Stimulants are banned in competition by the World Anti-Doping Agency, except for a small number of therapeutic agents subject to monitoring, and a large number of compounds have been placed on the prohibited list. However, a number of agents available as over the counter medicines for therapeutic uses, although subject to monitoring, may enhance performance. In addition, a large number of other unlisted stimulants are available, some of which appear in athlete’s samples. There is only very limited information on the relative potencies of even monitored agents as stimulants. For some agents even the mode of action is not well understood. This project seeks to supply that information. In this project, the stimulant actions of a wide range of compounds, prohibited, specified, monitored or unlisted, will be investigated in pharmacological and physiological bioassays in an animal model. This study will provide data giving direct measurement of the relative potencies of a wide range of stimulants at a number of biomarkers of stimulant action. The results will allow informed decisions on the doping potential of monitored substances relative to prohibited or unlisted substances. The wider implications are that these bioassays can be quickly performed to give robust information on any new compound appearing in athlete samples or to decide on the acceptable agents and doses for approved therapeutic uses. Generation and dissemination of detailed pharmacological information is essential to prevent doping in sport and to provide alternative therapies. 

    Main Findings:

    1. Bupropion is a stronger noradrenaline reuptake blocker than previously reported. It is likely to have both peripheral cardiovascular stimulant actions and central behavioural actions in doses used clinically.
    2. The majority of direct adrenoceptor stimulants investigated in this study showed relatively high potency as β-adrenoceptor agonists in producing a tachycardia. Although β1-adrenoceptor stimulation may be of limited benefit in sport (see Davis et al., 2008), this merits further consideration, especially if some of these agents are found to have additional  β2-adrenoceptor agonist actions.
    3. Cathine is likely to be an α2-adrenoceptor agonist, and this merits further study, as central clonidine-like actions as well as peripheral actions may be important for this agent.
    4. Selective actions at α1D-adrenoceptors occur for a number of agents. It is unclear if this action is of benefit in enhancing performance. This merits further investigation.
    5. Locomotor studies by telemetry are a useful method to study central stimulant actions. Both bupropion and modafinil were found to have central stimulant actions in doses employed.
    6. A large amount of data have been obtained on the cardiovascular effects of 12 receptor stimulants, and on the peripheral and central effects of 3 monoamine transporter blockers.  On publication, this will greatly increase the literature on the pharmacology of these agents.  On acceptance for publication, copies of these papers will be forwarded to WADA.

    Voir le projet à propos de Cardiovascular and central actions of drugs classed as stimulants
  • Certified Internal Standards for accuracy in longitudinal monitoring for testosterone abuse

    Certified Internal Standards for accuracy in longitudinal monitoring for testosterone abuse

    By

    Investigateur principal
    S. Davies

    Commonwealth of Australia

    Australie   ―   2011   ―   Complété

    Sommaire

    Code: 11A6SD 

    The aim of the project is to provide an isotopically labelled internal standard of a key testosterone metabolite. These will facilitate high accuracy measurement of this analyte in human urine thereby contributing to WADAs implementation of the Athletes Passport. The synthesis of d4-epitestosterone-17-b-glucuronide will be performed using a combination of literature precedents and chemistry routinely used by the Chemical Reference Materials team at NMI Australia. This material will be purified to the highest level possible using chromatographic and recrystallisation techniques. The material will then be fully characterised to afford fit for purpose status for use as an internal standard. The identity will be confirmed using a range of spectroscopic techniques including nuclear magnetic resonance, infrared spectroscopy and mass spectrometry. This will be complimented by analysis using a range of traditional techniques (HPLC with ELS detection, Karl Fischer moisture analysis and thermogravimetric analysis) to determine the chemical purity of the material. The isotopic purity will be determined using mass spectrometry on either the deglucuronidated steroid (GC-MS) or direct analysis of the parent material (LC-MS). 
    Fully certified material will be packaged in 1 mg lots and made available to all WADA accredited laboratories. 

    Main Findings: 

    This summarizes the synthesis of 1,16,16,17-d4-epitestosterone-17-O--glucuronic acid (1) using a combination of literature precedents and chemistry used previously by the Chemical Reference Materials team.  The material has undergone extensive purification to minimise impurities of similar structure.   
    HPLC analysis with photodiode array detection (PDA) confirmed an organic purity in excess of 99% mass fraction.  The overall purity value was lower (~93% mass fraction) than the idealised >99% mass fraction, which can be attributed to significant mass fractions of occluded water.  This is typical for glucuronic acids of this type and no attempt was made to remove the water because of concerns that the inevitable re-absorption of moisture would introduce stability issues.The isotopic purity of each material has been determined using GC-MS analysis of the de-glucuronidated steroid entity, confirming high levels of deuteration, with essentially zero non-deuterated (d0) present, making the isotopically labelled internal standard fit for its intended purpose.   The structure of the 1,16,16,17-d4-epitestosterone-17-O--glucuronic acid (1) has been unequivocally determined using a combination of spectroscopic techniques . Direct comparison with the spectroscopic data obtained for a fully certified sample of non-deuterated epitestosterone-17-O--glucuronic acid confirmed the regio- and stereochemistry. Further evidence was provided by co-elution studies of the parent compound and/or the liberated steroid moiety, with the fully certified native counterparts.
     Mass spectrometry
     Infra-Red spectroscopy
    1H / 2H / 13C Nuclear Magnetic Resonance spectroscopy
    1,16,16,17-d4-Epitestosterone-17-O--glucuronic acid (1) was assessed for chemical purity using a complementary range of analytical techniques to determine the mass fraction of the main component. Full characterisation and certification of this material has been performed and each material is currently available to the Australian Sports Drug Testing Laboratory (ASDTL) and other sports doping control laboratories around the world. 

     

    Voir le projet à propos de Certified Internal Standards for accuracy in longitudinal monitoring for testosterone abuse
  • Characterization and detection of prolonged Endothelin receptors antagonists administration

    Characterization and detection of prolonged Endothelin receptors antagonists administration

    By

    Investigateur principal
    S. Ostojic

    Centre for Health, Excercise and Sports Sciences

    Serbie   ―   2011   ―   Complété

    Sommaire

    Code: 11C2SO

    Endothelin receptors antagonists (ERA), such as bosentan and ambrisentan, are a class of vasoactive drugs that have been developed for the treatment of pulmonary arterial hypertension. It has been anecdotally reported that ERA is frequently used among top-level athletes to counteract exercise-induced rise in pulmonary vascular pressures and increase exercise performance. Yet, the effects of ERA on exercise capacity in healthy humans are puzzling, with the drugs not included in the current Prohibited List, since the ergogenic potential is yet to be fully understood and determined. Furthermore, the urinary excretion of ERA metabolites following administration has not been studied systematically at rest and during exercise in athletes, as a way to detect its intake if performance-enhancing potential is confirmed. In the planned study ERA will be administered in newly approved doses for 8 weeks in order to assess the presumed doping potential for both male and female athletes, and to monitor serum and urinary ERA excretion dynamics after single- and multiple-dose administration. The possible effects of prolonged ERA administration in higher doses on exercise performance may be relevant, if further confirmed, in terms of their possible fraudulent utilization to influence exercise performance in sports, raising the difficult question of whether, particularly in some circumstances, the ERA might be considered as prohibited substances in athletes. 

    Main Findings: 

    Endothelin receptors antagonists (ERA) are a class of vasoactive drugs that have been developed for the treatment of pulmonary arterial hypertension (PAH). The use of ERA among athletes to counteract exercise-induced rise in pulmonary vascular pressures and increase exercise performance is rather unexplored and data on efficacy and safety are limited. In particular, an increase of maximal oxygen consumption after ERA administration can be regarded as critical and should be evaluated.  
    The present study evaluated the effects of orally administered selective (bosentan) and non-selective ERA (ambrisentan) on aerobic and anaerobic performance, serum and urine biochemical outcomes, and the occurrence of adverse events during the intervention in healthy humans. Thirty male and female volunteers were randomized in a double-blind design to receive bosentan (250 mg daily), ambrisentan (10 mg per day) or placebo by oral administration for 8 weeks. Treatment with two different oral doses of ERA for 8 weeks had no major effect on body composition, strength, aerobic and anaerobic performance indicators and hormone profiles in physically active men and women as compared to placebo (p > 0.05). Serum hepatic enzymes increased significantly from before to after administration in both ERA groups (P < 0.001).  
    The proportion of participants who reported minor adverse events was similar in all intervention groups. These preliminary data suggest that 8-week oral administration of ERA is ineffective for exercise performance enhancement in healthy men and women, with significant effect on liver enzyme efflux and minimal incidence of reported side-effects.

    Voir le projet à propos de Characterization and detection of prolonged Endothelin receptors antagonists administration
  • Characterization of main metabolites of 17-methylstenblone and 17-methylmethonolone produced by human hepatocytes and liver fractions

    Characterization of main metabolites of 17-methylstenblone and 17-methylmethonolone produced by human hepatocytes and liver fractions

    By

    Investigateur principal
    C. Ayotte

    Institut Armand-Frapier (INRS)

    Canada   ―   2011   ―   Complété

    Sommaire

    Code: 11A16CA

    New steroids openly appear on the market in products labelled with a rather confusing nomenclature. Once characterized, pharmaceutical grade products not being available, knowledge of the biotransformation pathways essential to an efficient detection of utilization by athletes is difficult to gain since administration to human volunteers should be restricted to the minimum.  
    The alternative is a reliable in vitro model.  Human hepatocytes, fresh or cryopreserved are now available commercially. We have successfully produced and identified phase I metabolites from incubations of human hepatocytes with different steroids, such as 17-methyldrostanolone and desoxymethyltestosterone (DMT). 
    The aim of this project is to produce in vitro from human hepatocytes and liver fractions the metabolites of two steroids, the 17-methylated derivatives of stenbolone and its isomer methenolone. The principal metabolites will be synthesized and characterized by NMR and mass spectrometry. 
    The characterization of metabolites will enable the identification of markers of utilization to be incorporated in routine testing methods. The approach for the chemical synthesis of metabolites will be shared with NMI insuring the distribution to other doping control laboratories. Improving the knowledge of steroid biotransformation is a further benefit from these studies. 

    Main Findings:

    We have synthesized and characterized two designer steroids, 17α-methylmethenolone and 17α-methylstenbolone; the latter is proposed on the internet and two groups have reported different and contradictory results.  Incubations with fresh hepatocytes and S9 liver fractions were carried out. Structures were proposed for the main and more relevant metabolites from the GC-MS analysis of their TMS-ether, TMS-enol and TMS-ether (TMS-d9) derivatives in agreement with literature published for the non-methylated analogs methenolone and stenbolone (1-3).  A GC-MS/MS SRM method was developed and permitted the detection of these metabolites in an athlete’s sample in which methylstenbolone was detected and also in a reference urine sample provided by WAADS in 2014.   
    In vitro metabolites of 17α-methylmethenolone 1 
    Three main metabolites 6,17β-dihydroxy-1,17α-dimethyl-5α-androst-1-en-3-one (M2), 
    16,17β-dihydroxy-1,17α-dimethyl-5α-androst-1-en-3-one (M3) and 2,17β-dihydroxy-1,17α-dimethyl-5α-androst-1-en-3-one (M4)  were produced from the incubation of 1 with cryopreserved and fresh hepatocytes or S9 fractions, along with a trace of the 3α-OH metabolite (M1, 3α-SDH).   In vitro metabolites of 17α-methylstenbolone 2 
    The incubations of methylstenbolone with hepatocytes and S9 fractions afforded several metabolites.  Three, along with the reduced 3α-OH M1 were more important and expected to be present in human urine: 17β, 18-dihydroxy-2,17α-dimethyl-5α-androst-1-en-3-one (M2), 6,17β-dihydroxy-2,17α-dimethyl-5α-androst-1-en-3-one (M3), 16,17β-dihydroxy-2,17α-dimethyl-5α-androst-1-en-3-one (M4)

    Voir le projet à propos de Characterization of main metabolites of 17-methylstenblone and 17-methylmethonolone produced by human hepatocytes and liver fractions
  • Clenbuterol in meat: a source for a positive doping control? Search for analytical strategy to distinguish abuse from meat contamination

    Clenbuterol in meat: a source for a positive doping control? Search for analytical strategy to distinguish abuse from meat contamination

    By

    Investigateur principal
    S. Sterk

    RIKILT Institute for Food Safety

    Pays-Bas   ―   2011   ―   Complété

    Sommaire

    Code: 11A18SS

    Clenbuterol is a well known beta-agonist which is being used in animal husbandry and sports for growth promoting purposes. Lately adverse analytical findings in athletes were claimed to be due to contaminated meat. This project is aimed at finding a strategy and marker to distinguish Clenbuterol in urine from athletes due to meat consumption or illegal use of Clenbuterol containing supplement or preparations. 
    The hypothesis is that Clenbuterol, a racemic (1:1) mixture of stereoisomers as a pure compound, is present in another composition, 3:1, in meat due to differences in pharmacokinetics and pharmacodynamics. Ingestion of this different ratio from meat can lead to a different ratio in athletes urine. If this is the case then it is possible to discriminate consumption of contaminated meat from illegal administration of Clenbuterol (supplements).  For this, methods of analysis have to be developed to separate the stereoisomers in supplements, meat and urine.   
    Extraction of Clenbuterol from meat must be optimised because the incidence of positive Clenbuterol findings in residue control is very low. And several poisoning cases and positive doping cases have been found. So there is a possible underestimation of Clenbuterol residues in meat due to possible bound residues or incompete extraction. 
    Information on levels of the different isomers in meats has to be collected. As also quantification of stereoisomers in preparations and urine samples from controlled studies or from inadverted use from eg. tourists. 
    After that a proposal, workflow, how to use these tools in doping control must be developed. 

    Main Findings:

    WADA funded project 11A18SS was written to show a proof of principle that it is possible to discriminate adverse analytical findings by clenbuterol illegal use from consumption of contaminated meat. 
    Tools for this proof of principle were developed. 
    Sensitive and selective analytical methods were developed using UHPLC-MS/MS and SFC-MS/MS for meat, bovine and human urine and preparations. 
    Incurred meat with clenbuterol was produced. 
    The tools were used on real samples provided by anti-doping laboratories. 
    It was shown that meat from an animal treated with clenbuterol contained a different S/R ratio for clenbuterol. The meat was R-enantiomer enriched. 
    Pharmaceutical preparations showed S/R ratio around 1. 
    From the small number of urine samples from Mexico, presumed to be contaminated via meat the S/R clenbuterol ratio were lower than the S/R clenbuterol ratio from humans having consumed clenbuterol in an administration trial. 

     

    Voir le projet à propos de Clenbuterol in meat: a source for a positive doping control? Search for analytical strategy to distinguish abuse from meat contamination
  • Detection of autologous blood transfusion by analysis of erythrocyte density fractions and flow cytometry

    Detection of autologous blood transfusion by analysis of erythrocyte density fractions and flow cytometry

    By

    Investigateur principal
    T. Pottgiesser

    University Hospital of Freiburg

    Allemagne   ―   2011   ―   Complété

    Sommaire

    Code: 11B16TP

    Although autologous blood transfusions are a prohibited method, there is at present no unequivocal test and it seems from recent scandals that the technique remains a significant problem in various sports. During the past months and years, several research attempts to develop a valid detection method have been performed but so far have failed to identify a definite, unequivocal test. Whereas a method for detection of homologous blood transfusion was established in 2002, the most contemporary (indirect) attempt to detect autologous transfusions is the Athlete Biological Passport. 
    In this one-year project, our group focuses on the detection of autologous blood transfusion by a detailed analysis of red blood cell density fractions which could be altered in the time course after transfusion. In this context, the so-called ‘neocytolysis’ as a presumed selective destruction of young red blood cells (neocytes) was described as a process to possibly down-regulate hemoglobin mass when it is “excessive” or maladaptive for the environment and was seen as potentially important in blood doping settings. Several researchers assume that this regulation of red cells can be expressed when measuring their main density fractions. 
    In a pilot study, as an unexpected, but compelling and promising finding, our group was able to show that the transfusion of autologous blood leads to a distinct shift in the red cell density fractions with an increase of red cells of a high density. Flow cytometry with measurement of red blood cell surface markers shall be used to further evaluate these shifts and to allow identification of a certain set of markers being specific for autologous transfusion. This project will consist of a cross-sectional and longitudinal part where multiple transfusions and a control group shall be included to test for reproducibility and specificity of the methods. 

    Main Findings:

    The most important result of this project was the transfusion of autologous blood, predominantly with long-term storage for 7 weeks, lead to distinct changes of the RBC population shortly after transfusion. These effects were not detectable in full blood but in RBC samples from high density band established by sel-forming Percll gradients based on several parameters. However, the time window for detection of thse changes seems to be short, possibly being limited to a maximum of 24 up to 48/72 hours depending on the tested parameter. Systemic reactions to autologous transfusions were supported by the analysis of classical markers such as serum ferritin and hematology measurements showing significant changes which support the high value of serum ferritin as an important marker of autologous transfusion. However, we were unable to demonstrate any significant effect of autologous transfusion n the RBC surface marker profile in full blood or one of the three RBC subpopulations. In summary, we believe that the methods will be difficult to implement in the routine of any antidoping laboratory. Because of the elaborate preparations and short detection window (perhaps only valid for long stored blood). This project unfortunaly may not reveal a direct test for autologous blood doping at this stage. Nevertheless, the results are very interesting from a physiological point of view and will be discussed in the next paragraphs. In the last section, we will further comment on possible applications for on-going and future research in the field. 

    Voir le projet à propos de Detection of autologous blood transfusion by analysis of erythrocyte density fractions and flow cytometry
  • Page précédente
  • Première page 01
  • …
  • Page 44
  • Page en cours 45
  • Page 46
  • Dernière page Fin »
  • Page suivante
Haut de page

Pied de page

  • Système d'administration et de gestion antidopage (ADAMS)
  • Plateforme d'apprentissage en ligne de l'AMA (ADEL)
  • Autorisation d'usage à des fins thérapeutiques (AUT)
  • Liste des interdictions
  • Brisez le silence - Signalez le dopage
  • Emplois - Venez travailler avec nous
  • Conditions d'utilisation
  • Politique de confidentialité
  • Suivez-nous sur Facebook
  • Suivez-nous sur Instagram
  • Suivez-nous sur Twitter
  • Suivez-nous sur LinkedIn
  • Suivez-nous sur Youtube
speed skating