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Metabolic dysregulation in vitamin E and carnitine shuttle energy mechanisms associate with human frailty
James Nazroo, Royston Goodacre, Neil Pendleton, Frederick Wu, Iain White, Bram Vanhoutte, Gindo Tampubolon, Alan Marshall, Krisztina Mekli, Zahra Rattray, Tarani Chandola, Caroline Johnson, Drupad Trivedi, Yun Xu, Nicholas Rattray, 2019, izvirni znanstveni članek

Opis: Global ageing poses a substantial economic burden on health and social care costs. Enabling a greater proportion of older people to stay healthy for longer is key to the future sustainability of health, social and economic policy. Frailty and associated decrease in resilience plays a central role in poor health in later life. In this study, we present a population level assessment of the metabolic phenotype associated with frailty. Analysis of serum from 1191 older individuals (aged between 56 and 84 years old) and subsequent longitudinal validation (on 786 subjects) was carried out using liquid and gas chromatography-mass spectrometry metabolomics and stratified across a frailty index designed to quantitatively summarize vulnerability. Through multivariate regression and network modelling and mROC modeling we identified 12 significant metabolites (including three tocotrienols and six carnitines) that differentiate frail and non-frail phenotypes. Our study provides evidence that the dysregulation of carnitine shuttle and vitamin E pathways play a role in the risk of frailty.
Najdeno v: osebi
Ključne besede: metabolomics, frailty, ageing, LC-MS, serum
Objavljeno: 08.11.2019; Ogledov: 1397; Prenosov: 47
.pdf Polno besedilo (2,35 MB)

Detection and quantification of exhaled volatile organic compounds in mechanically ventilated patients–comparison of two sampling methods
Iain R. White, Pouline M. van Oort, Waqar Ahmed, Craig Johnson, Jonathan Bannard-Smith, Timothy Felton, Lieuwe D. Bos, Royston Goodacre, Paul Dark, Stephen J. Fowler, 2020, izvirni znanstveni članek

Opis: Exhaled breath analysis is a promising new diagnostic tool, but currently no standardised method for sampling is available in mechanically ventilated patients. We compared two breath sampling methods, first using an artificial ventilator circuit, then in “real life” in mechanically ventilated patients on the intensive care unit. In the laboratory circuit, a 24-component synthetic-breath volatile organic compound (VOC) mixture was injected into the system as air was sampled: (A) through a port on the exhalation limb of the circuit and (B) through a closed endo-bronchial suction catheter. Sorbent tubes were used to collect samples for analysis by thermal desorption-gas chromatography-mass spectrometry. Realistic mechanical ventilation rates and breath pressure–volume loops were established and method detection limits (MDLs) were calculated for all VOCs. Higher yields of VOCs were retrieved using the closed suction catheter; however, for several VOCs MDLs were compromised due to the background signal associated with plastic and rubber components in the catheters. Different brands of suction catheter were compared. Exhaled VOC data from 40 patient samples collected at two sites were then used to calculate the proportion of data analysed above the MDL. The relative performance of the two methods differed depending on the VOC under study and both methods showed sensitivity towards different exhaled VOCs. Furthermore, method performance differed depending on recruitment site, as the centres were equipped with different brands of respiratory equipment, an important consideration for the design of multicentre studies investigating exhaled VOCs in mechanically ventilated patients.
Najdeno v: osebi
Ključne besede: Volatile organic compounds, infection, breath, ventilator associated pneumonia
Objavljeno: 10.12.2020; Ogledov: 703; Prenosov: 0
.pdf Polno besedilo (1,61 MB)

Comparative Analysis of urban atmospheric aerosol by particle-induced X-ray emission (PIXE), proton elastic scattering analysis (PESA), and aerosol mass spectrometry (AMS)
Katja Džepina, Mario J. Molina, V. Shutthanandan, Luisa T. Molina, Dara Salcedo, K.S. Johnson, A. Laskin, Jose L. Jimenez, 2008, izvirni znanstveni članek

Opis: A multifaceted approach to atmospheric aerosol analysis is often desirable infield studies where an understanding of technical comparability among different measurement techniques is essential. Herein, we report quantitative intercomparisons of particle-induced X-ray emission (PIXE) and proton elastic scattering analysis (PESA), performed offline under a vacuum, with analysis by aerosol mass spectrometry (AMS) carried out in real-time during the MCMA-2003 Field Campaign in the Mexico City Metropolitan Area. Good agreement was observed for mass concentrations of PIXE-measured sulfur (assuming it was dominated by SO42-) and AMS-measured sulfate during most of the campaign. PESA-measured hydrogen mass was separated into sulfate H and organic H mass fractions, assuming the only major contributions were (NH4)(2)SO4 and organic compounds. Comparison of the organic H mass with AMS organic aerosol measurements indicates that about 75% of the mass of these species evaporated under a vacuum. However similar to 25% of the organics does remain under a vacuum, which is only possible with low-vapor-pressure compounds, and which supports the presence of high-molecular-weight or highly oxidized organics consistent with atmospheric aging. Approximately 10% of the chloride detected by AMS was measured by PIXE, possibly in the form of metal-chloride complexes, while the majority of Cl was likely present as more volatile species including NH4Cl. This is the first comparison of PIXE/PESA and AMS and, to our knowledge, also the first report of PESA hydrogen measurements for urban organic aerosols.
Najdeno v: osebi
Ključne besede: organic aerosols, secondary organic aerosols, Mexico City, MCMA-2003 field campaign
Objavljeno: 11.04.2021; Ogledov: 402; Prenosov: 0
.pdf Polno besedilo (1,74 MB)

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