Studies on the in vivo metabolism of the SARM YK11: Identification and characterization of metabolites potentially useful for doping controls.

A steroidal compound was recently detected in a seized black market product and was identified as (17α,20E)-17,20-[(1-methoxyethylidene) bis (oxy)]-3-oxo-19-norpregna-4,20-diene-21-carboxylic acid methyl ester (YK11). This compound is described to possess selective androgen receptor modulator- and myostatin inhibitor-like properties. As YK11 is an experimental drug candidate and a non-approved substance for humans, scientific data on its metabolism is scarce.

Epiandrosterone sulfate prolongs the detectability of testosterone, 4-androstenedione, and dihydrotestosterone misuse by means of carbon isotope ratio mass spectrometry.

In the course of investigations into the metabolism of testosterone (T) by means of deuterated T and hydrogen isotope ratio mass spectrometry, a pronounced influence of the oral administration of T on sulfoconjugated steroid metabolites was observed. Especially in case of epiandrosterone sulfate (EPIA_S), the contribution of exogenous T to the urinary metabolite was traceable up to 8 days after a single oral dose of 40 mg of T. These findings initiated follow-up studies on the capability of EPIA_S to extend the detection of T and T analogue misuse by carbon isotope ratio (CIR) mass spectrometry in sports drug testing.

The atypical excretion profile of meldonium: Comparison of urinary detection windows after single- and multiple-dose application in healthy volunteers.

Following a one-year monitoring program providing unequivocal analytical evidence for a high prevalence in international elite sports, meldonium has been included in the World Anti-Doping Agency's (WADA) list of prohibited substances that came into effect on 1 January 2016. Despite of the polar and hydrophilic nature of the molecule, an unusual long detection window was observed in pilot elimination studies. Consequently, in the present study, urinary excretion profiles after single-dose (5 volunteers, 1×500mg) and multiple-dose oral application (5 volunteers; 2×500mg/day for 6days) were determined in order to facilitate the result management concerning meldonium findings in doping controls.

Periostin gene variants are associated with disease course and severity in juvenile idiopathic arthritis.

Objectives: This study aimed to identify polymorphic variants of the Periostin gene associated with disease severity and clinical course in children with juvenile idiopathic arthritis.

Methods: DNA genotyping of 7 single-nucleotide polymorphisms within the periostin gene was performed in 117 patients and their parents and in 102 control samples. Our patients were divided in the following 4 disease categories: 1) persistent oligoarthritis; 2) extended oligoarthritis; 3) polyarthritis; 4) systemic arthritis.

Use of dried blood spots in doping control analysis of anabolic steroid esters.

Dried blood spot (DBS) sampling, a technique for whole blood sampling on a piece of filter paper, has more than 50-years tradition, particularly in the diagnostic analysis of metabolic disorders in neonatal screening. Due to the minimal invasiveness, straightforwardness, robustness against manipulation and fastness DBS sampling recommends itself as an advantageous technique in doping control analysis. The present approach highlights the development of a screening assay for the analysis of eight anabolic steroid esters (nandrolone phenylpropionate, trenbolone enanthate, testosterone acetate, testosterone cypionate, testosterone isocaproate, testosterone phenylpropionate, testosterone decanoate and testosterone undecanoate) and nandrolone in DBS.

Ultrahigh pressure liquid chromatography-(tandem) mass spectrometry in human sports drug testing: possibilities and limitations.

Doping control analytical laboratories for human sports predominantly employ nowadays chromatographic-mass spectrometric test methods for routine, high throughput screening and confirmation assays concerning low and high molecular mass analytes. Liquid chromatography-(tandem) mass spectrometry [(LC-MS(/MS)] and particularly ultrahigh pressure liquid chromatography (UHPLC)-MS/MS instruments have become devices of choice due to their indispensable capabilities that compensate for limitations inherent to other commonly used strategies such as immunological and gas chromatography-(tandem) mass spectrometry [(GC-MS(/MS)]-based detection methods. UHPLC-MS/MS-based assays at low mass spectrometric resolution have been established allowing for fast and sensitive targeted analyses focusing on pre-selected target analytes with diagnostic precursor-product ion pairs.