2011 Postgraduate Research Competition - UNSW Science - The ...

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Improved measurement of stable carbon
isotope ratios of steroids in urine for the detection of
steroid abuse
Ellaine Munton, Brynn Hibbert and John Murby
Abstract
Testosterone is a naturally occurring steroid that can be misused by athletes for its anabolic
effects. The World Anti-Doping Agency (WADA) reported that results indicating potential
testosterone abuse accounted for 46% of all adverse analytical findings in 2009, far more
than any other form of doping. Administration of exogenous testosterone is confirmed by
comparing the carbon isotope ratios of testosterone metabolites in the urine with those of
endogenous reference compounds. A difference of 3 ‰ or more between these carbon
isotope ratios (equivalent to a difference of 0.00327 % in the 13C mole fraction) is consistent
with abuse. As these differences are very small, it is important that the measurements have
minimal measurement uncertainty. This project aims to improve the quality of isotope ratio
measurements for urinary steroids by optimising the extraction procedure.
Each step in the extraction was optimised for maximum recovery and minimal isotopic
fractionation: Solid Phase Extraction (SPE) from the urine matrix; removal of the glucuronide
conjugate with β-glucuronidase; Liquid-Liquid Extraction (LLE) from aqueous solution; and
High Performance Liquid Chromatography (HPLC) purification. A new calibration and δ13C
value calculation procedure was also developed in order to improve the estimation of the
measurement uncertainty.
Abstract
Frequent Hepatitis C
Multiple Infections in a Prison Cohort
Son Truong Pham and Peter White
School of Biotechnology & Biomolecular Sciences
Hepatitis C virus (HCV) infects 2-3% of the world’s population, causing severe liver diseases.
Recent data indicate infection with multiple HCV occurs, and are common among injecting
drug users (IDU). In the present study, we sought to identify and characterise multiple HCV
infections among incident HCV infected IDU inmates (n=87) enrolled into an Australian prison
cohort. Multiple infections were detected using two reverse transcription - polymerase chain
reactions targeting the Core region and the envelope glycoprotein-1 together with the
hyper-variable region-1. Among 87 subjects, infection by two or more HCV were identified in
22 subjects (25.3%), with the prevalence of 31.3% and the incidence of 40/100 person-years
(95% CI, 33-44/100 person-years) during follow-up. The rate of successful clearance of all
viruses among 22 cases was 23/100 person-years (95% CI, 19-31/100 person-years).
Spontaneous HCV clearance from one HCV and persistence of the other HCV was observed
in eight cases. In these cases, the virus with higher HCV RNA level out-competed the other,
suggesting that HCV RNA level is an important factor in viral competition and infection
outcome. This study comprehensively analyses frequent multiple HCV infections in a high-risk
cohort and provides further insights into infection dynamics after exposure to variant HCV.
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