Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Carine Schweizer is active.

Publication


Featured researches published by Carine Schweizer.


Journal of Chromatography A | 2001

Method for confirmation of synthetic corticosteroids in doping urine samples by liquid chromatography–electrospray ionisation mass spectrometry

Karl Fluri; Laurent Rivier; Agnes Dienes-Nagy; Chunhui You; Arnaud Maı̂tre; Carine Schweizer; Martial Saugy; Patrice Mangin

In this study, we report on the development of a method to confirm simultaneously nine of the most commonly abused synthetic corticosteroids in urine based on liquid chromatography-electrospray ionisation mass spectrometry. A considerable simplified sample preparation procedure, including liquid-liquid phase extraction with Extrelut-NT3 columns, provided both excellent sample purification and high overall recoveries. Complete HPLC separations were obtained on a reversed-phase column with 1 mM ammonium acetate-acetonitrile (60:40, v/v) as mobile phase. Mass spectral acquisition was done in the negative ion, and selected ion monitoring modes to identify the drugs with at least three characteristic ions. Detection limits were determined at < or =1 ng/ml and the confirmation limits at 1 to 5 ng/ml.


Journal of Chromatography B: Biomedical Sciences and Applications | 1996

Detection of human growth hormone doping in urine: out of competition tests are necessary☆

Martial Saugy; Christine Cardis; Carine Schweizer; Jean-Luc Veuthey; Laurent Rivier

The misuse of human growth hormone (hGH) in sport is deemed to be unethical and dangerous because of various adverse effects. Thus, it has been added to the International Olympic Committee list of banned substances. Until now, the very low concentration of hGH in the urine made its measurement difficult using classical methodology. Indeed, for routine diagnosis, only plasma measurements were available. However, unlike blood samples, urine is generally provided in abundant quantities and is, at present, the only body fluid allowed to be analysed in sport doping controls. A recently developed enzyme-linked immunosorbent assay (Norditest) makes it now possible, without any extraction, to measure urinary hGH (u-hGH) in a dynamic range of 2-50 ng hGH/l. In our protocol, untreated and treated non-athlete volunteers were followed. Some of them received therapeutical doses of recombinant hGH (Norditropin) for one week either intramuscularly (three increasing doses) or subcutaneously (12 i.u. every day). The u-hGH excretion after treatment showed dramatic increases of 50-100 times the basal values and returned to almost the mean normal level after 24 h. u-hGH was also measured in samples provided by the anti-doping controls at major and minor competitions. Depending on the type of efforts made during the competition, the hGH concentration in urine was dramatically increased. Insulin-like growth factor binding proteins and beta 2-microglobulins in urine and/or in blood could be necessary for the correct investigation of any hGH doping test procedure.


British Journal of Sports Medicine | 2009

Steroid profiles of professional soccer players: an international comparative study

Emmanuel Strahm; Pierre-Edouard Sottas; Carine Schweizer; Martiel Saugy; Jiri Dvorak; Christophe Saudan

Background and objectives: Urinary steroid profiling is used in doping controls to detect testosterone abuse. A testosterone over epitestosterone (T/E) ratio exceeding 4.0 is considered as suspicious of testosterone administration, irrespectively of individual heterogeneous factors such as the athlete’s ethnicity. A deletion polymorphism in the UGT2B17 gene was demonstrated to account for a significant part of the interindividual variability in the T/E between Caucasians and Asians. Here, the variability of urinary steroid profiles was examined in a widely heterogeneous cohort of professional soccer players. Method: The steroid profile of 57 Africans, 32 Asians, 50 Caucasians and 32 Hispanics was determined by gas chromatography–mass spectrometry. Results: Significant differences have been observed between all ethnic groups. After estimation of the prevalence of the UGT2B17 deletion/deletion genotype (African: 22%; Asian: 81%; Caucasian: 10%; Hispanic: 7%), ethnic-specific thresholds were developed for a specificity of 99% for the T/E (African: 5.6; Asian: 3.8; Caucasian: 5.7; Hispanic: 5.8). Finally, another polymorphism could be hypothesised in Asians based on specific concentration ratio of 5α-/5β-androstane-3α,17β-diol in urine. Conclusion: These results demonstrate that a unique and non-specific threshold to evidence testosterone misuse is not fit for purpose. An athlete’s endocrinological passport consisting of a longitudinal follow-up together with the ethnicity and/or the genotype would strongly enhance the detection of testosterone abuse. Finally, additional genotyping studies should be undertaken to determine whether the remaining unexplained disparities have an environmental or a genetic origin.


The Journal of Steroid Biochemistry and Molecular Biology | 2013

Profiling of steroid metabolites after transdermal and oral administration of testosterone by ultra-high pressure liquid chromatography coupled to quadrupole time-of-flight mass spectrometry

Flavia Badoud; Julien Boccard; Carine Schweizer; François P. Pralong; Martial Saugy; Norbert Baume

The screening of testosterone (T) misuse for doping control is based on the urinary steroid profile, including T, its precursors and metabolites. Modifications of individual levels and ratio between those metabolites are indicators of T misuse. In the context of screening analysis, the most discriminant criterion known to date is based on the T glucuronide (TG) to epitestosterone glucuronide (EG) ratio (TG/EG). Following the World Anti-Doping Agency (WADA) recommendations, there is suspicion of T misuse when the ratio reaches 4 or beyond. While this marker remains very sensitive and specific, it suffers from large inter-individual variability, with important influence of enzyme polymorphisms. Moreover, use of low dose or topical administration forms makes the screening of endogenous steroids difficult while the detection window no longer suits the doping habit. As reference limits are estimated on the basis of population studies, which encompass inter-individual and inter-ethnic variability, new strategies including individual threshold monitoring and alternative biomarkers were proposed to detect T misuse. The purpose of this study was to evaluate the potential of ultra-high pressure liquid chromatography (UHPLC) coupled with a new generation high resolution quadrupole time-of-flight mass spectrometer (QTOF-MS) to investigate the steroid metabolism after transdermal and oral T administration. An approach was developed to quantify 12 targeted urinary steroids as direct glucuro- and sulfo-conjugated metabolites, allowing the conservation of the phase II metabolism information, reflecting genetic and environmental influences. The UHPLC-QTOF-MS(E) platform was applied to clinical study samples from 19 healthy male volunteers, having different genotypes for the UGT2B17 enzyme responsible for the glucuroconjugation of T. Based on reference population ranges, none of the traditional markers of T misuse could detect doping after topical administration of T, while the detection window was short after oral TU ingestion. The detection ability of the 12 targeted steroids was thus evaluated by using individual thresholds following both transdermal and oral administration. Other relevant biomarkers and minor metabolites were studied for complementary information to the steroid profile, including sulfoconjugated analytes and hydroxy forms of glucuroconjugated metabolites. While sulfoconjugated steroids may provide helpful screening information for individuals with homozygotous UGT2B17 deletion, hydroxy-glucuroconjugated analytes could enhance the detection window of oral T undecanoate (TU) doping.


Clinical Journal of Sport Medicine | 2004

Doping test reveals high concentrations of salbutamol in a Swiss track and field athlete.

Carine Schweizer; Martial Saugy; Matthias Kamber

Beta-2 agonists are on the list of prohibited substances in sport. Salbutamol by inhalation is permitted to treat allergic asthma, and/or exercise-induced asthma or exercise-induced bronchoconstriction. If the level of salbutamol in urine exceeds 1000 ng/mL, the result is considered as a doping violation with an anabolic steroid. We report a case of a track and field athlete who tested well above this limit during a competition. He had a valid therapeutic use exemption for the use of salbutamol by inhalation and he claimed that he never used salbutamol orally. Further studies under controlled application by inhalation showed that this limit was exceeded. We propose that sanctioning bodies in sport should consider this possibility before taking into account a two-year ban for the use of an anabolic steroid.


Bioanalysis | 2014

Untargeted profiling of urinary steroid metabolites after testosterone ingestion: opening new perspectives for antidoping testing.

Julien Boccard; Flavia Badoud; Nicolas Jan; Raul Nicoli; Carine Schweizer; François P. Pralong; Jean-Luc Veuthey; Norbert Baume; Serge Rudaz; Martial Saugy

AIM Antidoping procedures are expected to greatly benefit from untargeted metabolomic approaches through the discovery of new biomarkers of prohibited substances abuse. RESULTS Endogenous steroid metabolites were monitored in urine samples from a controlled elimination study of testosterone undecanoate after ingestion. A platform coupling ultra-high pressure LC with high-resolution quadrupole TOF MS was used and high between-subject metabolic variability was successfully handled using a multiblock data analysis strategy. Links between specific subsets of metabolites and influential genetic polymorphisms of the UGT2B17 enzyme were highlighted. CONCLUSION This exploratory metabolomic strategy constitutes a first step toward a better understanding of the underlying patterns driving the high interindividual variability of steroid metabolism. Promising biomarkers were selected for further targeted study.


British Journal of Sports Medicine | 2015

Antidoping programme and biological monitoring before and during the 2014 FIFA World Cup Brazil.

Norbert Baume; Nicolas Jan; Caroline Emery; Béatrice Mandanis; Carine Schweizer; Sylvain Giraud; Nicolas Leuenberger; François Marclay; Raul Nicoli; Laurent Perrenoud; Neil Robinson; Jiri Dvorak; Martial Saugy

Background The FIFA has implemented an important antidoping programme for the 2014 FIFA World Cup. Aim To perform the analyses before and during the World Cup with biological monitoring of blood and urine samples. Methods All qualified players from the 32 teams participating in the World Cup were tested out-of-competition. During the World Cup, 2–8 players per match were tested. Over 1000 samples were collected in total and analysed in the WADA accredited Laboratory of Lausanne. Results The quality of the analyses was at the required level as described in the WADA technical documents. The urinary steroid profiles of the players were stable and consistent with previously published papers on football players. During the competition, amphetamine was detected in a sample collected on a player who had a therapeutic use exemption for attention deficit hyperactivity disorder. The blood passport data showed no significant difference in haemoglobin values between out-of-competition and postmatch samples. Conclusions Logistical issues linked to biological samples collection, and the overseas shipment during the World Cup did not impair the quality of the analyses, especially when used as the biological passport of football players.


Forensic Science International | 2008

From population- to subject-based limits of T/E ratio to detect testosterone abuse in elite sports

Pierre-Edouard Sottas; Christophe Saudan; Carine Schweizer; Norbert Baume; Patrice Mangin; Martial Saugy


Biostatistics | 2007

Bayesian detection of abnormal values in longitudinal biomarkers with an application to T/E ratio

Pierre-Edouard Sottas; Norbert Baume; Christophe Saudan; Carine Schweizer; Matthias Kamber; Martial Saugy


Best Practice & Research Clinical Endocrinology & Metabolism | 2000

Test methods: anabolics.

Martial Saugy; Christine Cardis; Neil Robinson; Carine Schweizer

Collaboration


Dive into the Carine Schweizer's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Jiri Dvorak

Fédération Internationale de Football Association

View shared research outputs
Researchain Logo
Decentralizing Knowledge