Screening anabolic androgenic steroids in human urine: an application of the state-of-the-art gas chromatography-Orbitrap high-resolution mass spectrometry.

Over the past few decades, anabolic androgenic steroids (AASs) have been abused in and out of competition for their performance-enhancing and muscle-building properties. Traditionally, AASs were commonly detected using gas chromatography-mass spectrometry in the initial testing procedure for doping control purposes. Gas chromatography-Orbitrap high-resolution mass spectrometry (GC-Orbitrap-HRMS) is a new technology that has many advantages in comparison with GC-MS (e.g., a maximum resolving power of 240,000 (FWHM at m/z 200), excellent sub-ppm mass accuracy, and retrospective data analysis after data acquisition). Anti-doping practitioners are encouraged to take full advantage of the updated techniques of chromatography-mass spectrometry to develop sensitive, specific, and rapid screening methods for AASs. A new method for screening a wide range of AASs in human urine using GC-Orbitrap-HRMS was developed and validated. The method can qualitatively determine 70 anabolic androgenic steroids according to the minimum required performance limit of the World Anti-Doping Agency. Moreover, the validated method was successfully applied to detect six metabolites in urine after the oral administration of metandienone, and their excretion curves in vivo were studied. Metandienone M6 (17ß-hydroxymethyl-17α-methyl-18-nor-androst-1,4,13-trien-3-one) has been identified as a long-term urinary metabolite which can be detected up to 7 weeks, thus providing a longer detection window compared with previous studies. This study provides a rationale for GC-Orbitrap-HRMS in drug metabolism and non-targeted screening.

The regulatory role of LncRNA HCG18 in various cancers.

As a member of long non-coding RNAs (lncRNAs), LncRNA HLA complex group 18 (HCG18) has recently become the focus of cancer research. As outlined in this review, LncRNA HCG18 has been reported to be dysregulated in various cancers development and appears to be activated in a variety of tumors, including clear cell renal cell carcinoma (ccRCC), colorectal cancer (CRC), gastric cancer (GC), hepatocellular carcinoma (HCC), laryngeal and hypopharyngeal squamous cell carcinoma (LHSCC), lung adenocarcinoma (LUAD), nasopharyngeal cancer (NPC), osteosarcoma (OS), and prostate cancer (PCa). Furthermore, the expression of lncRNA HCG18 decreased in bladder cancer (BC) and papillary thyroid cancer (PTC). Overall, the presence of these differential expressions suggests the clinical value of HCG18 in cancer therapy. Additionally, lncRNA HCG18 influences various biological processes of cancer cells. This review summarizes the molecular mechanisms of HCG18 in cancer development, highlights reported the abnormal expression of HCG18 found in various cancer types, and aims to discuss the potential of HCG18 as a target for cancer therapy.

Derivatization-Enhanced Analysis of Glucocorticoids for Structural Characterization by Gas Chromatography-Orbitrap High-Resolution Mass Spectrometry.

Glucocorticoids are classified in section S9 of the Prohibited List of the World Anti-Doping Agency, due to a potential risk to improving physical performance and causing harm to the health of athletes. Based on the similar physiological actions of glucocorticoids, both differentiating known glucocorticoids and identifying unknown glucocorticoids are important for doping control. Gas chromatography coupled with mass spectrometry plays an important role in structural characterization because of abundant structural diagnostic ions produced by electron ionization. It also provides a chance to study the fragmentation patterns. Thus, an enhanced derivatization procedure was optimized to produce trimethylsilylated glucocorticoids and structural diagnostic ions of nineteen trimethylsilylated glucocorticoids were obtained by gas chromatography-orbitrap high-resolution mass spectrometry. In our study, glucocorticoids were classified as: 3-keto-4-ene, 1,4-diene-3-keto, 3α-hydroxy with saturated A-ring, 21-hydroxy-20-keto and halo substituent glucocorticoids based on their structural difference. Structural diagnostic ions that contributed to structural characterization were specifically presented and the fragment patterns were demonstrated according to the above categories. This study not only gave new insights into the structural characterization of these glucocorticoids but also provided evidence for tracing unknown glucocorticoids or chemically modified molecules.

Quantification of urinary steroids by supported liquid extraction with GC-MS/MS: Unravelling cyclic fluctuations of steroid profiling in regular menstrual cycle.

A method for simultaneous quantification of urinary steroids has been developed using supported liquid extraction technique in combination with gas chromatography-triple quadruple tandem mass spectrometry. The supported liquid extraction technique could enrich low-concentration analytes by reducing matrix interference, hence the technique offered better extraction efficiency compared to conventional preparation methods. The method was shown to be linear (r2 > 0.99) in the range of concentrations for all steroids with accuracy ranging from 88.0% to 115.6%. The intra- and inter-day precision, expressed as relative standard deviation, were both below 11.9%. The lower limits of quantification were between 1 and 50 ng·mL-1, and the limits of detection were between 0.5 and 2.5 ng·mL-1, which were suitable for the detection of steroids. The validated method was subsequently applied for analyzing urinary steroid profiling in regular menstrual cycle. The cyclic fluctuations and positive correlations between the steroids in different phases were observed. The results indicated that the proposed method was an effective tool for revealing hormonal fluctuations during menstrual cycle in complex biological samples.

Headspace-Low Water Absorption Trap Technique: Analysis of Low-Abundance Volatile Compounds from Fresh Artemisia Annua L. with GC-MS.

Conventional headspace (HS) method could not meet the requirement of analyzing low-abundance volatile compounds in high water content samples. A HS-low water absorption trap technique coupled with gas chromatography-mass spectrometry was introduced to remove the large amount of water vapor; therefore, the low-abundance volatile compounds could be detected with better analytical sensitivity. With this method, a total of 81 volatile compounds were identified from fresh Artemisia annua L. by mass spectral library search, retention index and accurate mass measurement, which could make the qualitative results more accurate and reliable. These compounds belonged to different species, including terpene, cycloparaffin, aliphatic aldehyde, aromatic ketone, aromatic aldehyde and so on. The 2,5,6-trimethyl-1,3,6-heptatriene (8.23%) was the most principal compound, followed by γ-muurolene (6.80%), ß-caryophyllenea (6.24%), 1,8-cineol (5.76%), 2-carene (5.65%), borneol (5.57%), isocaryophyllene (4.91%), bornylene (4.78%), camphene (4.30%) and ß-pinene (4.26%) as the main components. The results indicated that this method presents a great potential for the trace analysis of volatile compounds in complex high water content samples.