Urinary volatile organic compounds for the detection of prostate cancer

© 2015 Khalid et al.This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 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

Quantum suppression of antihydrogen formation in positronium-antiproton scattering

Calculation of antihydrogen formation from antiproton-positronium collisions, with the positroniun in excited states. Novelty is the extension to positronium states with principal quantum numbers 4 and 5 and the discovery that the increase in the cross section is muted over simple expectations due to a suppression effect.This effect is due to a centrifugal barrier-type effect, which markedly reduces the influence of the higher angular momentum components which typically provide the cross section enhancements at lower values of n

Antihydrogen formation in low-energy antiproton collisions with excited-state positronium atoms

© 2018, Springer Nature Switzerland AG. The convergent close-coupling method is used to obtain cross sections for antihydrogen formation in low-energy antiproton collisions with positronium (Ps) atoms in specified initial excited states with principal quantum numbers ni= 5. The threshold behaviour as a function of the Ps kinetic energy, E, is consistent with the 1/E law expected from threshold theory for all initial states. We find that the increase in the cross sections is muted above ni= 3 and that here their scaling is roughly consistent with ni2, rather than the classically expected increase as ni4

Gender gaps and reentry into entrepreneurial ecosystems after business failure

Despite the significant role played by serial entrepreneurs in the entrepreneurial process, we know little about group differences in reentry decisions after business failure. Using an ecosystems framework and stigma theory, we investigate the variance in gender gaps related to the reentry decisions of 8,171 entrepreneurs from 35 countries who experienced business failures. We find evidence of persisting gender gaps that vary across ecosystem framework conditions of public stigma of business failure and public fear of business failure. Our findings shed new light on ecosystem inefficiencies that arise from multiple interactions between entrepreneurs and institutions

Mitochondrial and ER-targeted eCALWY probes reveal high levels of free Zn2+

Zinc (Zn2+) ions are increasingly recognized as playing an important role in cellular physiology. Whereas the free Zn2+ concentration in the cytosol has been established to be 0.1-1 nM, the free Zn2+ concentration in subcellular organelles is not well-established. Here, we extend the eCALWY family of genetically encoded Förster Resonance Energy Transfer (FRET) Zn2+ probes to permit measurements in the endo(sarco)plasmic reticulum (ER) and mitochondrial matrix. Deployed in a variety of mammalian cell types, these probes reveal resting mitochondrial free [Zn2+] values of ~300 pM, somewhat lower than in the cytosol but 3 orders of magnitude higher than recently reported using an alternative FRET-based sensor. By contrast, free ER [Zn2+] was found to be =5 nM, which is >5000-fold higher than recently reported but consistent with the proposed role of the ER as a mobilizable Zn2+ store. Treatment of ß-cells or cardiomyocytes with sarco(endo)plasmic reticulum Ca2+-ATPase inhibitors, mobilization of ER Ca2+ after purinergic stimulation with ATP, or manipulation of ER redox, exerted no detectable effects on [Zn2+]ER. These findings question the previously proposed role of Ca2+ in Zn2+ mobilization from the ER and suggest that high ER Zn2+ levels may be an important aspect of cellular homeostasis

Two-symmetry Penning-Ioffe trap for antihydrogen cooling and spectroscopy

High-accuracy spectroscopic comparisons of trapped antihydrogen atoms (H) and hydrogen atoms (H) promiseto stringently test the fundamental CPT symmetry invariance of the standard model of particle physics. ATRAP’snested Penning-Ioffe trap was developed for such studies. The first of its unique features is that its magneticIoffe trap forHatoms can be switched between quadrupole and octupole symmetries. The second is that itallows laser and microwave access perpendicular to the central axis of the traps

Controversies in using urine samples for prostate cancer detection: PSA and PCA3 expression analysis

PURPOSE: Prostate cancer (PCa) is one of the most commonly diagnosed malignancies in the world. Although PSA utilization as a serum marker has improved prostate cancer detection it still presents some limitations, mainly regarding its specificity. The expression of this marker, along with the detection of PCA3 mRNA in urine samples, has been suggested as a new approach for PCa detection. The goal of this work was to evaluate the efficacy of the urinary detection of PCA3 mRNA and PSA mRNA without performing the somewhat embarrassing prostate massage. It was also intended to optimize and implement a methodological protocol for this kind of sampling. MATERIALS AND METHODS: Urine samples from 57 patients with suspected prostate disease were collected, without undergoing prostate massage. Increased serum PSA levels were confirmed by medical records review. RNA was extracted by different methods and a preamplification step was included in order to improve gene detection by Real-Time PCR. RESULTS: An increase in RNA concentration with the use of TriPure Isolation Reagent. Despite this optimization, only 15.8% of the cases showed expression of PSA mRNA and only 3.8% of prostate cancer patients presented detectable levels of PCA3 mRNA. The use of a preamplification step revealed no improvement in the results obtained. CONCLUSION: This work confirms that prostate massage is important before urine collection for gene expression analysis. Since PSA and PCA3 are prostate specific, it is necessary to promote the passage of cells from prostate to urinary tract, in order to detect these genetic markers in urine samples