169 research outputs found

    Microbial volatile organic compounds - a path towards rapid non-invasive detection of wound infections

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    The detection of microbial volatile organic compounds (VOCs) has previously demonstrated potential as a non-invasive diagnostic tool for a variety of infectious diseases and disorders. The objectives of this thesis were to firstly, illustrate and describe the close association between microbial and clinical volatilomics; secondly, to characterise the volatilomes of key wound-associated pathogens and to explore the factors influencing their VOC emission; and finally, to demonstrate the application of VOC analysis for the detection of wound infections. Chapter 1 of this report is a review of past and current literature surrounding the field of microbial and clinical volatilomics. The most common experimental methods used across microbial and clinical volatilomic studies are discussed with the aim of highlighting the critical need for standardization of these techniques across the field. This chapter finally illustrates the close association between microbial VOCs and disease and describes potential opportunities for clinical applications in the future. Chapter 2 describes the comprehensive in vitro volatilomic profiling of prevalent wound-associated bacterial pathogens. In this work, species- and strain-level volatilomic diversity were explored by utilizing a simple experimental workflow coupled with robust multivariate analysis techniques. Temporal stability of microbial VOC emissions was also investigated and measured against to cell growth. Chapter 3 was a further investigation of these pathogens. The aims of this study were to examine the influence of different nutritional media on the VOC output of the bacterial pathogens and to investigate strain-level volatilomic differences in VOC emission kinetics. In Chapter 4, the focus of investigation was shifted to fungal pathogens to characterise the factors surrounding VOC emission in multiple Candida species. In this work, volatile metabolites from 10 clinical strains of planktonic C. parapsilosis and one strain of planktonic C. albicans were profiled. The effect of biofilm formation on the C. parapsilosis volatilomes was investigated for the first time by comparing volatilomes of a biofilm-positive strain and a biofilm-negative strain over time using a novel sampling approach. In the final chapter of this thesis, our rapid noninvasive experimental workflow was employed for the analysis of wound swab samples. 23 participants (26 wounds total, 15 infected; 11 non-infected) were included in this work. The volatilomes of infected and non-infected wound samples are characterised and compoundlevel differences between them are described in this chapter. The results of this ongoing work provide clear insight into the potential of volatilomics for future clinical applications. Overall this collective work demonstrates the close association between microbial and clinical volatilomics and highlights the clear potential for volatilomics to be used for clinical diagnoses of wound infections. This thesis concludes with a short discussion of the future outlook of this work

    Methods for Monitoring Endoplasmic Reticulum Stress and the Unfolded Protein Response

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    The endoplasmic reticulum (ER) is the site of folding of membrane and secreted proteins in the cell. Physiological or pathological processes that disturb protein folding in the endoplasmic reticulum cause ER stress and activate a set of signaling pathways termed the Unfolded Protein Response (UPR). The UPR can promote cellular repair and sustained survival by reducing the load of unfolded proteins through upregulation of chaperones and global attenuation of protein synthesis. Research into ER stress and the UPR continues to grow at a rapid rate as many new investigators are entering the field. There are also many researchers not working directly on ER stress, but who wish to determine whether this response is activated in the system they are studying: thus, it is important to list a standard set of criteria for monitoring UPR in different model systems. Here, we discuss approaches that can be used by researchers to plan and interpret experiments aimed at evaluating whether the UPR and related processes are activated. We would like to emphasize that no individual assay is guaranteed to be the most appropriate one in every situation and strongly recommend the use of multiple assays to verify UPR activation

    Interleukin 15 Primes Natural Killer Cells to Kill via NKG2D and cPLA2 and This Pathway Is Active in Psoriatic Arthritis

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    NK cells are large granular lymphocytes that form a critical component of the innate immune system, whose functions include the killing of cells expressing stress-induced molecules. It is increasingly accepted that despite being considered prototypical effector cells, NK cells require signals to reach their full cytotoxic potential. We previously showed that IL-15 is capable of arming CD8 effector T cells to kill independently of their TCR via NKG2D in a cPLA2-dependent process. As NK cells also express NKG2D, we wanted to investigate whether this pathway functioned in an analogous manner and if resting NK cells could be primed to the effector phase by IL-15. Furthermore, to establish relevance to human disease we studied a possible role for this pathway in the pathogenesis of psoriatic arthritis, since there are aspects of this disease that suggest a potential effector role for the innate immune system. We found that PsA patients had upregulated IL-15 and MIC in their affected synovial tissues, and that this unique inflammatory environment enabled NK cell activation and killing via NKG2D and cPLA2. Moreover, we were able to reproduce the phenotype of joint NK cells from blood NK cells by incubating them with IL-15. Altogether, these findings suggest a destructive role for NK cells when activated by environmental stress signals during the pathogenesis of PsA and demonstrate that IL-15 is capable of priming resting NK cells in tissues to the effector phase

    Utilisation of pain counselling in osteopathic practice: Secondary analysis of a nationally representative sample of australian osteopaths

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    Objectives Advice, reassurance and education are recommended as first line treatments for musculoskeletal pain conditions such as low back pain. Osteopaths are registered primary contact allied health professionals in the Australian healthcare system who primarily manage acute and chronic musculoskeletal pain conditions. This study aimed to investigate the proportion of Australian osteopaths who do and do not utilise advice, reassurance and education (pain counselling) in their clinical practice, and determine the characteristics associated with the frequency of using pain counselling in clinical practice. Methods A secondary analysis of practice characteristics from a nationally representative sample of Australian osteopaths was undertaken. Participants completed a 27-item practice characteristics questionnaire between July-December 2016. Bivariate analyses were used to identify significant variables for inclusion in a backward multiple logistic regression model. Adjusted odds ratios (OR) were calculated for significant variables. Results Responses were received from 991 Australian osteopaths, representing 49% of the profession. Of these 264 (26.64%) indicated often utilising pain counselling, and 727 (73.36%) reported not often utilising pain counselling. Those who utilised pain counselling were more than twice as likely to report research evidence had a high impact on their clinical practice (OR 2.11), and nearly twice as likely to discuss physical activity with their patients (OR 1.84). Conclusions Pain counselling is under-utilised by nearly three quarters of the Australian osteopathic profession as a management strategy. Future studies are required to explore the reasons why most in the profession comprised in this sample are infrequently utilising this guideline recommendation. Given the frequency of chronic musculoskeletal pain conditions presenting to Australian osteopaths, strategies appear to be needed to advance the profession via professional development in accessing and using evidence-based care for pain conditions

    East Bay Coalition for the Homeless: Branding Study and Marketing Strategy

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    There are a number of potential positioning strategies. The two which make the most sense for the EBCH are to “position the EBCH away from others in the category” and to “position the EBCH as unique.” These strategies have the advantage of setting the EBCH apart from the other organizations that address homelessness. Occupying its own “position” in the minds of potential and current donors is not only an effective communications/marketing strategy but also a less costly one because it avoids head-to-head competition and comparisons

    The Apache Point Observatory Galactic Evolution Experiment (APOGEE) Spectrographs

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    We describe the design and performance of the near-infrared (1.51--1.70 micron), fiber-fed, multi-object (300 fibers), high resolution (R = lambda/delta lambda ~ 22,500) spectrograph built for the Apache Point Observatory Galactic Evolution Experiment (APOGEE). APOGEE is a survey of ~ 10^5 red giant stars that systematically sampled all Milky Way populations (bulge, disk, and halo) to study the Galaxy's chemical and kinematical history. It was part of the Sloan Digital Sky Survey III (SDSS-III) from 2011 -- 2014 using the 2.5 m Sloan Foundation Telescope at Apache Point Observatory, New Mexico. The APOGEE-2 survey is now using the spectrograph as part of SDSS-IV, as well as a second spectrograph, a close copy of the first, operating at the 2.5 m du Pont Telescope at Las Campanas Observatory in Chile. Although several fiber-fed, multi-object, high resolution spectrographs have been built for visual wavelength spectroscopy, the APOGEE spectrograph is one of the first such instruments built for observations in the near-infrared. The instrument's successful development was enabled by several key innovations, including a "gang connector" to allow simultaneous connections of 300 fibers; hermetically sealed feedthroughs to allow fibers to pass through the cryostat wall continuously; the first cryogenically deployed mosaic volume phase holographic grating; and a large refractive camera that includes mono-crystalline silicon and fused silica elements with diameters as large as ~ 400 mm. This paper contains a comprehensive description of all aspects of the instrument including the fiber system, optics and opto-mechanics, detector arrays, mechanics and cryogenics, instrument control, calibration system, optical performance and stability, lessons learned, and design changes for the second instrument.Comment: 81 pages, 67 figures, PASP, accepte
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