Analytical and Bioanalytical Chemistry v. Anti-doping analysis by
Benfluorex fdating Thevis His research interests include the development of methods targeting non-approved emerging drugs with potential for misuse in sport, elucidation of metabolic pathways of drug candidates, and, particularly, the identification of peptidic drugs and their metabolites in blood and urine.
He has published over articles in peer-reviewed international journals, authored a book on mass spectrometry in sports drug testing, received the Manfred—Donike and Beynon—Price awards, and is Editor-in-Chief of Drug Testing and Analysis. Doping analysis relies on the determination of prohibited substances that should not be present in the body "Benfluorex fdating" an athlete or that should
Benfluorex fdating below a threshold value.
In the case of xenobiotics their mere presence is sufficient to establish a doping offence. However, in the case of human biotics the analytical method faces the difficulty of distinguishing between endogenous and exogenous origin. For this purpose ingenious strategies have been implemented, often aided by state-of-the-art technological advancements such as mass spectrometry in all its possible forms.
For larger molecules, i. Although approaches these confer specificity and sensitivity to the applications, most rely on the use of two, or even three, antibody incubations with the consequent increment in assay variability.
The development of analytical techniques to measure interactions directly, such as atomic force microscopy, quartz crystal microbalance
Benfluorex fdating surface plasmon resonance, have greatly contributed to the accurate evaluation of molecular interactions in all fields of biology, and expectations are that this will only increase.
Here, an overview is provided of surface plasmon resonance, and its particular value in application to the field of doping analysis.
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Figure SPR analysis to assist antidoping procedures. Surface plasmon resonance; Doping analysis; Proteins and immunoassay. One approach is to focus on pre-selected target analytes that are measured with utmost specificity and sensitivity using diagnostic precursor—product ion pairs in low resolution
Benfluorex fdating mass spectrometers. Examples of recent applications of sports drug testing procedures published between and are presented and discussed, outlining the particular advantages of the selected approaches as well as their limitations in a short- and long-term perspective.
Prevalence of legal "Benfluorex fdating" illegal stimulating agents in sports by K.
This paper reviews the prevalence of legal and illegal stimulants in relation to doping-control analysis. Stimulants are among the oldest classes of doping agents, having been used since ancient times. Despite the ease
Benfluorex fdating which they can be detected and the availability of sensitive detection methods, stimulants are still popular among athletes.
Indeed, they remain one of the top three most popular classes of prohibited substances. Because the list of legal and illegal stimulants is extensive only a selection is discussed in detail.
The compounds selected are caffeine, ephedrines, amphetamine and related compounds, methylphenidate, cocaine, strychnine, modafinil, adrafinil, 4-methylhexaneamine, and sibutramine. These compounds are mainly prevalent in sport or are of therapeutic importance. Because stimulants are the oldest doping class the first detection methods were for this group.
In particular, the last technique has been shown to enable successful detection of stimulants difficult to detect by GC—MS or for stimulants previously undetectable. Because stimulants are also regularly detected in nutritional food supplements a section on this topic is also included. Recent developments in the use of isotope ratio mass spectrometry in sports drug testing by Thomas Piper; Caroline Emery; Martial Saugy According to the annual report of the World Anti-Doping Agency, steroids are the most frequently detected class of doping agents.
Detecting the misuse of endogenously occurring steroids, i. A variety of
Benfluorex fdating methods has been developed throughout the last decade and the number of different steroids under investigation by isotope ratio mass spectrometry has recently grown considerably.
Besides norandrosterone, boldenone was found to occur endogenously
Benfluorex fdating rare cases and the misuse of corticosteroids or epitestosterone can now be detected with the Benfluorex fdating of carbon isotope ratios as well.
In addition, steroids excreted as sulfoconjugates were investigated, and the first results regarding hydrogen isotope ratios recently became available. All of these will be presented in detail within this review together with some considerations on validation issues and on identification of parameters influencing
Benfluorex fdating isotope ratios in urine.
Carbon isotope ratio; Hydrogen isotope ratio; Steroid profile; Steroid metabolism; Doping control. Detecting growth hormone abuse in athletes by Richard I.
It is believed that athletes have been abusing
Benfluorex fdating hormone GH for its anabolic and lipolytic effects since the early s, at least a decade before endocrinologists began to treat adults with GH deficiency. There is an on-going debate about whether GH is performance enhancing. Although many of the early studies were negative, more recent studies suggest that GH improves strength and sprint capacity, particularly when it is combined with anabolic steroids. Two approaches have been developed to detect GH abuse.
The first is based on measurement of pituitary GH isoforms; after injection of recombinant "Benfluorex fdating" GH, which comprises solely the kDa isoform, endogenous production is down-regulated leading to an increase in the kDa isoform relative to other isoforms. The second is based on measurement of
Benfluorex fdating of GH action. When combined with discriminant function analysis, use of these markers differentiates between individuals taking GH and placebo.
Subsequent studies have shown that the test is applicable across different ethnicities and is unaffected by injury. WADA regulations state
Benfluorex fdating when analytes are measured by immunoassay, two assays are needed.
Final validation of the marker test is currently being undertaken with modern commercially available immunoassays to finalise the threshold values to be used to determine whether a doping offence has been committed. Recent developments in doping testing for erythropoietin by Christian Reichel The constant development of new erythropoiesis-stimulating agents ESAssince the first introduction of recombinant erythropoietin rhEpo for clinical use, has also necessitated constant development of methods for detecting the abuse of these substances.
Since the first publication of a direct and urine-based detection method inwhich uses changes in the Epo isoform profile as detected by isoelectric focusing in polyacrylamide slab gels IEF-PAGEthe method has been constantly adapted to the appearance of new ESAs e.
Blood had to be introduced as an additional matrix, because Mircera a PEGylated Epo is best
Benfluorex fdating in serum or plasma after immunoaffinity purification.
Benfluorex fdating of Dynepo and copy epoetins, the additional application of sodium dodecylsulfate polyacrylamide gel electrophoresis SDS-PAGE or equivalent became necessary. The haematological module of the Athlete Biological Passport is the latest development in multivariable indirect testing for ESA doping.
The article summarizes "Benfluorex fdating" main strategies currently used in Epo anti-doping testing with special focus on new developments made between and Figure Recent developments in doping testing for Epo include mass-based methods. The importance of reference materials in doping-control analysis by Lindsey G. Mackay; Rymantas Kazlauskas Currently a large range of pure substance reference materials are available for calibration of doping-control methods.
Only a small number of prohibited substances have threshold limits for which quantification is highly important. For these analytes only the highest quality reference materials that are available should be used. Many prohibited substances have no threshold limits and reference materials provide essential identity confirmation.
For these reference materials the correct identity is critical
Benfluorex fdating the methods used to assess identity in these cases should be critically evaluated. There is still a lack of certified "Benfluorex fdating" reference materials to support many aspects of doping analysis.
These matrix-certified reference materials CRMs are an excellent independent means of
Benfluorex fdating method recovery and bias and will typically be used in method validation and then regularly as quality-control checks. They can be particularly important in the analysis of samples close to threshold limits, in which measurement accuracy becomes critical. Some reference materials for isotope ratio mass spectrometry IRMS analysis are available and a matrix material certified for steroid delta values is currently under production.
"Benfluorex fdating" other new areas, for example the Athlete Biological Passport, peptide hormone testing, designer steroids, and gene doping, reference material needs still need
Benfluorex fdating be thoroughly assessed and prioritised.
Certified reference materials; Reference materials; Doping.
As recently reported, the synthetic cannabinoid JWH is the
Benfluorex fdating of extensive phase I and II metabolic reactions in vivo. Existing doping control methods were expanded and validated according to international guidelines in order to allow for the detection of the "Benfluorex fdating" and the alkylhydroxy metabolites, respectively, as urinary markers for the illegal intake of the synthetic cannabinoid JWH Both metabolites were quantified in authentic doping control urine samples that had been suspicious of JWH abuse after routine Benfluorex fdating procedures, and a stable isotope-labelled 13 C 8 - 15 N-carboxy metabolite was synthesised for future analytical applications.
A family of small peptides has reached the focus of doping controls representing a comparably new strategy for cheating sportsmen. These growth hormone releasing peptides GHRP are orally active and induce an increased production of endogenous growth hormone GH. While the established test for exogenous GH fails, the misuse of these prohibited substances remains unrecognized.
This is of great importance due to the currently unknown metabolism of most of the targets and, thus, the method is focused on the intact peptidic drugs. Only the already characterised major metabolite of GHRP-2 d -Ala- d naphthylAla- l -Ala, as well as its stable isotope-labelled analogue was synthesised and implemented in the detection assay. Methods of blood doping such as autologous and homologous blood transfusion are one of the main challenging doping practices in competitive sport.
Apr 17, the nature of...
Whereas homologous blood "Benfluorex fdating" is detectable via minor blood antigens, the detection of autologous blood transfusion is still not feasible. A promising approach to indicate homologous or autologous blood transfusion is the quantification of increased urinary levels of di 2-ethylhexyl phthalate DEHP metabolites found after blood transfusion.
Benfluorex fdating forward, rapid and reliable assay is presented for the quantification of the main metabolites mono 2-ethyloxohexyl phthalate, mono 2-ethylhydroxyhexyl phthalate and mono 2-ethylhexyl phthalate that can easily be implemented into existing multi-target methods used for sports drug testing. Benfluorex fdating. Study of the...
The investigation demonstrates that significantly increased levels of secondary DEHP metabolites were found in urine samples of transfused patients, strongly indicating blood transfusion. Urinary excretion profiles of toremifene metabolites by liquid chromatography-mass spectrometry. In the present study, toremifene urinary excretion studies were evaluated in order to examine main
Benfluorex fdating reactions and to select target metabolites in doping control analysis.
The elemental compositions of the compounds detected were determined by liquid chromatography-mass spectrometry using a time-of-flight system with accurate mass
Benfluorex fdating. More "Benfluorex fdating" structure elucidation was obtained by monitoring the presence or absence of structure-specific ions, using product ion scan and neutral loss acquisition modes, whereas the metabolites urinary profiles were evaluated in selected reaction monitoring acquisition mode.
The results showed that the main routes of phase-I modifications involved carboxylation of the chlorinated side chain, N -demethylation and hydroxylation in different positions.
These metabolites can be divided in two groups: The
Benfluorex fdating abundant and long-term compounds were the carboxylated metabolites followed by the hydroxylated metabolites. Their product ions originating Benfluorex fdating collision-induced dissociation were observed to occur prevalently in the dimethylaminoethoxy and in the chlorinated side chains.
These structure-specific ions were used to design screening and confirmation procedures to positively identify toremifene administration in doping control analysis. Due to its potentially performance-enhancing properties, benfluorex has been added to the list of prohibited compounds and methods of doping by the World Anti-Doping Agency WADA in
Benfluorex fdating the implementation of the drug as well as its major metabolites into routine doping control procedures.
Stabilization of human urine doping control samples: Transportation of doping control urine samples from the collection sites to the World Anti-doping Agency WADA
Benfluorex fdating Laboratories is conducted under ambient temperatures.
When sample delivery is not immediate, microbial contamination of urine, especially in summer, is a common phenomenon that may affect sample integrity and may result in misinterpretation of analytical data. Furthermore, the possibility of intentional contamination of sports samples during collection
Benfluorex fdating proteolytic enzymes, masking the abuse of prohibited proteins such as erythropoietin EPO and peptide hormones, is a practice that has already been reported.
Currently, no stabilization method is applied in the sample collection equipment system in order to prevent degradation of urine compounds. The present work is an overview of a study, funded by WADA, on degradation and stabilization aspects of sports urine samples against the above threats of degradation.
Extensive method development resulted in the creation of a mixture of chemical agents for the stabilization of urine. Evaluation of results demonstrated that the stabilization mixture could stabilize endogenous steroids, recombinant EPO, and human chorionic gonadotropin in almost the entire range of the experimental conditions tested.
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Benfluorex fdating Benfluorex fdating. Study of the Effect of the Benfluorex (MEDIAGENE) The safety and scientific validity of this study is the responsibility of the study sponsor and.
recommendations of IAS audits dating back to and called into question and staff dealing with any of the benfluorex group of drugs were screened on.