Blow fly responses to semiochemicals produced by decaying carcasses.

Volatiles from mouse carcasses in decay stages ranging from fresh to 33 days old were used to investigate oriented flight and landings in male and female blow flies of Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae). Oriented flight increased significantly from 36% towards fresh carcasses to 68%, 61% and 65% towards carcasses aged 3 days, 6 days and 9 days, respectively. Carcasses aged 20 days and 33 days were significantly less attractive, achieving 51% and 41% attraction, respectively. No differences emerged between the sexes in oriented flight, but a significant increase in female landings at the most attractive carcasses was observed. Headspace collections from the different stages of decay showed a succession in the volatile profile emitted from the carcasses and identified nine chemicals which peak in quantity in concurrence with the most attractive stages of decay. Three of these chemicals also showed dose-response effects as indicated by a significant correlation between the amount present and the proportion of flies responding. Blow flies are important pests and efficient traps are needed. The significant interaction between fly sex and carcass age highlights behavioural differences between male and female blow flies which can be exploited in blow fly trapping. Three new volatile chemicals, butylated hydroxyl toluene, 3-hydroxy-2-butanone and nonanal, emitted from dead mice are suggested as potential attractants.

Chemometric evaluation of urinary steroid profiles in doping control.

Ten endogenous steroid hormones and metabolites were determined according to the screening procedure for anabolic steroids in spot urine samples from 105 healthy young male athletes (control samples) and 23 males that tested positive for anabolic steroids in the doping control (positive samples). The GC-MS peak areas for each sample were normalized to total area. Multivariate data analysis by Partial Least Square Regression (PLSR) and using a coded Y-variable (positive samples: +1 and control samples -1) allows projection of the most systematic profile structures into a 2D plot revealing a clear distinction between the control and misuser groups. The most important determinants of the location in the loading plot were the ratios of testosterone to epitestosterone and androsterone to etiocholanolone. The ratio between 11-beta-hydroxyandrosterone and 11-beta-hydroxy-etiocholanolone was less important, in accordance with the fact that anabolic-androgenic steroid intake primarily affects the excretion of testosterone from the testis and to a much lesser degree adrenal steroid genesis. We present a preliminary validation of this model (PLS1-DISCRIM) for analysing steroid profiles in doping control samples from several categories of athletes, some of which are suspected for drug misuse, and results from a one dose excretion study in healthy volunteers. Our findings suggest that use of multivariate PLS-regression may give valuable information about anabolic androgenic steroid misuse in sport. When appropriately calibrated, this methodology may delineate drug misusers directly from the screening procedure for anabolic steroids in spot urine tests.

Establishing a ketoconazole suppression test for verifying testosterone administration in the doping control of athletes.

The ratio of urinary testosterone (u-T) to epitestosterone (T/EpiT) is used to disclose testosterone (T) administration in the doping control of sports, and a ratio greater than 6 constitutes an offence. Nevertheless, the possibility of biological outliers must not be discounted, and the use of ketoconazole has been suggested for a dynamic test to distinguish between such athletes and those using T. In this investigation, ketoconazole was administrated to three groups of T-pretreated and two groups of untreated healthy male subjects. The subjects in one of the pretreated groups were patients with mild hypogonadism. One untreated group consisted of athletes that had been tested three times with high urinary T/EpiT levels. The effects of ketoconazole administration on serum T (s-T) level and urinary T/EpiT ratio were monitored every 2 h for an 8-h period and clearly separated T-pretreated and untreated subjects into two clusters (P < 0.0001). The T/EpiT ratio increased and the s-T level remained unchanged in pretreated individuals during the ketoconazole test, whereas T/EpiT decreased by 60% and s-T by almost 90% in untreated subjects. The statistical power of the test increased by using several time points and combining the urinary T/EpiT with the s-T data. In conclusion, the ketoconazole test is suitable as a supportive dynamic test for the urinary T/EpiT ratio measurements in the doping control of athletes.