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The reaction with two tyrosine nitration reagents, peroxynitrite and tetranitromethane was used to probe two conformational isomers of recombinant hamster prion protein. Results revealed that tyrosine nitration has identified two specific regions of the normal prion protein isoform that undergo a change in chemical environment upon conversion to a structure that is enriched in [beta]-sheet.

The hematological module of the Athlete Biological Passport (ABP) is used for indirect detection of blood manipulations; however, the use of this method to detect doping, such as with microdoses of recombinant human erythropoietin (rhEPO), is problematic. For this reason, the sensitivity of ABP must be enhanced by implementing novel biomarkers. Here, we show that 5'‐aminolevulinate synthase 2 (ALAS2) mRNAs are useful transcriptomic biomarkers to improve the indirect detection of rhEPO microdosing. Moreover, the sensitivity was sufficient to distinguish rhEPO administration from exposure to hypoxic conditions. Levels of mRNAs encoding carbonate anhydrase 1 (CA1) and solute carrier family 4 member 1 (SLC4A1) RNA, as well as the linear (L) and linear + circular (LC) forms of ALAS2 mRNA, were monitored for 16 days after rhEPO microdosing and during exposure to hypoxic conditions. ALAS2 mRNAs increased by 300% compared with the baseline values after rhEPO microdosing. Moreover, ALAS2 mRNAs were not significantly increased under hypoxic conditions. By contrast, CA1 mRNA was increased after both rhEPO microdosing and hypoxia, whereas SLC4A1 mRNA did not significantly increase under either condition. Furthermore, the analyses described here were performed using dried blood spots (DBSs), which provide advantages in terms of the sample collection, transport, and storage logistics. This study demonstrates that ALAS2 mRNA levels are sensitive and specific transcriptomic biomarkers for the detection of rhEPO microdosing using the hematological module of the ABP, and this method is compatible with the use of DBSs for anti‐doping analyses. [ABSTRACT FROM AUTHOR]

AOD9604 is a peptide consisting of the C-terminal fragment of human growth hormone from amino acids 177-191 with an additional tyrosine residue at the N-terminus of the peptide. It is reported to mimic the lipolytic properties of growth hormone without the diabetogenic side effects. Therefore, AOD9604 may be used as a performance enhancing drug and is banned by the World Anti-doping Agency (WADA). The peptide is available on several Internet websites and was recently identified in confiscated vials in the USA. To detect abuse of the peptide in athletes, a solid-phase extraction method was validated in urine with a limit of detection of 50 pg/mL. The method has good linearity, precision (<20%), specificity and recovery (62%). Six potential metabolites of the peptide were identified after incubation of AOD9604 in serum and urine. Quantification of the metabolites in serum identified a single metabolite, consisting of amino acids CRSVEGSCG, which is significantly more stable than the other metabolites or the parent compound. Screening for AOD9604 and the stable metabolite may potentially allow an increased window of detection. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]