Urinary Volatile Organic Compounds for the Detection of Prostate Cancer.

The aim of this work was to investigate volatile organic compounds (VOCs) emanating from urine samples to determine whether they can be used to classify samples into those from prostate cancer and non-cancer groups. Participants were men referred for a trans-rectal ultrasound-guided prostate biopsy because of an elevated prostate specific antigen (PSA) level or abnormal findings on digital rectal examination. Urine samples were collected from patients with prostate cancer (n = 59) and cancer-free controls (n = 43), on the day of their biopsy, prior to their procedure. VOCs from the headspace of basified urine samples were extracted using solid-phase micro-extraction and analysed by gas chromatography/mass spectrometry. Classifiers were developed using Random Forest (RF) and Linear Discriminant Analysis (LDA) classification techniques. PSA alone had an accuracy of 62-64% in these samples. A model based on 4 VOCs, 2,6-dimethyl-7-octen-2-ol, pentanal, 3-octanone, and 2-octanone, was marginally more accurate 63-65%. When combined, PSA level and these four VOCs had mean accuracies of 74% and 65%, using RF and LDA, respectively. With repeated double cross-validation, the mean accuracies fell to 71% and 65%, using RF and LDA, respectively. Results from VOC profiling of urine headspace are encouraging and suggest that there are other metabolomic avenues worth exploring which could help improve the stratification of men at risk of prostate cancer. This study also adds to our knowledge on the profile of compounds found in basified urine, from controls and cancer patients, which is useful information for future studies comparing the urine from patients with other disease states.

Metabolism of androstenone, 17ß-estradiol and dihydrotestosterone in primary cultured pig hepatocytes and the role of 3ß-hydroxysteroid dehydrogenase in this process.

Steroids metabolism plays an important role in mammals and contributes to quality of pig meat. The main objective of this study was to identify metabolites of androstenone, 17ß-estradiol and dihydrotestosterone using primary cultured pig hepatocytes as a model system. The role of 3ß-hydroxysteroid dehydrogenase (3ßHSD) in regulation of steroid metabolism was also validated using trilostane, a specific 3ßHSD inhibitor. Steroid glucuronide conjugated metabolites were detected by liquid chromatography time of flight mass spectrometry (LC-TOF-MS). 3ßHSD enzyme was essential for metabolism of androstenone to 5α-androst-16-en-3ß-ol, which then formed androstenone glucuronide conjugate. Metabolism of 17ß-estradiol was accompanied by formation of glucuronide-conjugated estrone and glucuronide-conjugated estradiol. The ratio of the two metabolites was around 5:1. 3ßHSD enzyme was not involved in 17ß-estradiol metabolism. 5α-Dihydrotestosterone-17ß-glucuronide was identified as a dihydrotestosterone metabolite, and this metabolism was related to 3ßHSD enzyme activity as demonstrated by inhibition study.

The relationship between growth stages and aroma composition of lemon basil Ocimum citriodorum Vis.

Volatiles from infusions of lemon basil Ocimum citriodorum Vis were evaluated by SPME-GC/MS. Citral, linalool and estragole were the major constituents. Citral, the major contributor to the lemony flavour, was significantly higher in post-flowering (79%) and full-flowering (65%), it was reduced to 42% at pre-flowering. Linalool was consistent throughout the growth cycle (2-3%). Estragole was higher in pre-flowering representing 15% of the total volatiles present. Linalool levels dropped sharply during the full-flowering and post-flowering stages to 2% and 0.4%, respectively. Volatiles from different parts of lemon basil were evaluated to determine the parts that influence the flavour. The percentage composition of citral for leaves and flowers was 64.5% and 58% for the branches. Linalool was much higher in flowers (13%), followed by 11% in branches and 3% in leaves. The flavour attributes of lemon basil infusions can be improved by incorporating aerial branches and flowers in the tea.

An investigation of volatile organic compounds from the saliva of healthy individuals using headspace-trap/GC-MS.

Analysis of volatile organic compounds (VOCs) from saliva, to aid disease diagnoses, has received little attention. This work aims to address the paucity of information on saliva volatiles and includes a database of newly identified compounds whilst incorporating a review of the literature. The volatile constituents in the headspace of whole saliva obtained from ten healthy individuals were examined in a longitudinal study over a period of ten days using headspace-trap gas chromatography-mass spectrometry (HS-trap/GC-MS). A total of 317 compounds (268 identified) were found and compared across subjects and between samples with 34 VOCs being present in all 100 samples. The average number of compounds per subject ranged from 121 to 150 over a 10 day period and was fairly consistent for a particular individual (s.d. ranged from 3-15). However, the number of compounds present in an individual on all ten days was substantially lower ranging between 65 and 109, showing that there is significant daily variation in salivary composition. A core group of ubiquitous VOCs were found with the remaining VOCs showing significant intra and inter individual variability. Saliva VOCs have been found to be readily analysed using the HS-trap technique and studies on the VOCs from healthy individuals should be of utility for comparison with VOCs analysed from samples from diseased groups.