Browsing by Author "Turner, Claire"
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Item Open Access Analysis of volatile marker compounds in body fluid samples from patients with gastrointestinal disease(Cranfield University, 2010-09) Fowler, Dawn P.; Turner, Claire; Walker, ChristopherCauses of gastrointestinal diseases such as ulcerative colitis (UC) Crohn’s disease (CD) and irritable bowel syndrome (IBS) are not yet completely understood and clinical investigation for diagnosis is invasive, costly and time consuming. Disease may originate from the host or in combination with commensal enteric bacteria, notably sulphate reducing bacteria. Examination of volatile compounds from clinical samples may provide indicators and better understanding into aetiology of these conditions and provide biomarkers for individual disease.Cont/d.Item Open Access Breath analysis in disease diagnosis: methodological considerations and applications(MDPI, 2014-06-20) Lourenco, Celia; Turner, ClaireBreath analysis is a promising field with great potential for non-invasive diagnosis of a number of disease states. Analysis of the concentrations of volatile organic compounds (VOCs) in breath with an acceptable accuracy are assessed by means of using analytical techniques with high sensitivity, accuracy, precision, low response time, and low detection limit, which are desirable characteristics for the detection of VOCs in human breath. “Breath fingerprinting”, indicative of a specific clinical status, relies on the use of multivariate statistics methods with powerful in-built algorithms. The need for standardisation of sample collection and analysis is the main issue concerning breath analysis, blocking the introduction of breath tests into clinical practice. This review describes recent scientific developments in basic research and clinical applications, namely issues concerning sampling and biochemistry, highlighting the diagnostic potential of breath analysis for disease diagnosis. Several considerations that need to be taken into account in breath analysis are documented here, including the growing need for metabolomics to deal with breath profiles.Item Open Access Diversity and distribution of sulphate-reducing bacteria in human faeces from healthy subjects and patients with inflammatory bowel disease(2012-06-01T00:00:00Z) Jia, Wenjing; Whitehead, Rebekah N.; Griffiths, Lesley; Dawson, Claire; Bai, Hao; Waring, Rosemary H.; Ramsden, David B.; Hunter, John O.; Cauchi, Michael; Bessant, Conrad M.; Fowler, Dawn P.; Walton, Christopher; Turner, Claire; Cole, Jeffrey A.The relative abundance of different groups of sulphate-reducing bacteria (SRB) in faecal DNA collected before and after therapy from patients suffering from Crohn's disease (CD), irritable bowel syndrome (IBS) or ulcerative colitis (UC) has been compared with that from healthy controls. Growth tests revealed that SRB were not more abundant in samples from patients with CD before treatment than in the healthy control group. For most of the 128 samples available, these preliminary results were confirmed using degenerate PCR primers that amplify the dsrAB gene. However, some samples from patients with CD before treatment contained a growth inhibitor that was absent from IBS or UC samples. In-depth sequencing of PCR-generated dsrB fragments revealed that the diversity detected was surprisingly low, with only eight strains of SRB and the sulphite-reducing bacterium, Bilophila wadsworthia, detected above the 0.1% threshold. The proportion of the two major species detected, B.wadsworthia and Desulfovibrio piger, was as high as 93.5% of the total SRB population in the healthy control group and lower in all patient groups. Four previously undescribed species were found: it is impossible to predict whether they are sulphate or sulphite-reducing bacteria.Item Open Access Electronic nose responses and acute phase proteins correlate in blood using a bovine model of respiratory infection(Elsevier, 2010-01) Knobloch, Henri; Schroedl, Wieland; Turner, Claire; Chambers, Mark; Reinhold, PetraThis study aimed (i) to assess the ability of electronic nose (e-nose) technology to differentiate between blood samples of experimentally infected and non-infected subjects, and (ii) to evaluate e-nose responses given by volatile organic compounds in relation to the acute phase reaction generated in the host. In an animal model of gram-negative bacterial infection (20 calves; intratracheal inoculation of Mannheimia haemolytica A1), the concentrations of the acute phase proteins (APPs; i.e. lipopolysaccharide binding protein and haptoglobin) were measured in serum samples before and after challenge, and headspaces of pre- and post-inoculation serum samples were analysed using a conducting polymer based e-nose. Significant changes of certain e-nose sensor responses allowed discrimination between samples before and after challenge. The maximal changes in responses of sensitive e-nose sensors corresponded to the peak of clinical signs. Significant correlations linked decreasing responses of multiple e-nose sensors to increasing concentrations of APPs in the peripheral blood.Item Open Access Enteral feeding reduces metabolic activity of the intestinal microbiome in Crohn’s disease: an observational study(Nature Publishing Group, 2016-05-11) Walton, Christopher; Montoya, M. P. B.; Fowler, Dawn P.; Turner, Claire; Jia, W.; Whitehead, Rebekah N.; Griffiths, Lesley; Waring, Rosemary H.; Ramsden, David B.; Cole, Jeffrey A.; Cauchi, Michael; Bessant, Conrad M.; Naylor, J.; Hunter, John O.BACKGROUND/OBJECTIVES: Enteral feeding will induce remission in as many as 80–90% of compliant patients with active Crohn’s disease (CD), but its method of action remains uncertain. This study was designed to examine its effects on the colonic microbiome. METHODS/SUBJECTS: Healthy volunteers and patients with CD followed a regimen confined to enteral feeds alone for 1 or 2 weeks, respectively. Chemicals excreted on breath or in faeces were characterised at the start and at the end of the feeding period by gas chromatography/mass spectrometry. RESULTS: One week of feeding in healthy volunteers caused significant changes in stool colour and deterioration in breath odour, together with increased excretion of phenol and indoles on the breath. Feeding for 2 weeks in patients with CD produced significant improvements in symptoms and a decrease in the concentration of C-reactive protein. The faecal concentrations of microbial products, including short-chain fatty acids (SCFAs), and potentially toxic substances, including 1-propanol, 1-butanol and the methyl and ethyl esters of SCFAs, showed significant falls. CONCLUSIONS: A significant change occurs in the production of microbial metabolites after enteral feeding in both healthy volunteers and patients with CD. Many of those detected in CD are toxic and may feasibly lead to the immunological attack on the gut microbiota, which is characteristic of inflammatory bowel disease. The reduction in the production of such metabolites after enteral feeding may be the reason for its effectiveness in CD.Item Open Access Evaluation of a gas sensor array and pattern recognition for the identification of bladder cancer from urine headspace.(Royal Society of Chemistry, 2011-01-21T00:00:00Z) Weber, Christina M.; Cauchi, Michael; Patel, Mitesh; Bessant, Conrad M.; Turner, Claire; Britton, Lezlie E.; Willis, Carolyn M.Previous studies have indicated that volatile compounds specific to bladder cancer may exist in urine headspace, raising the possibility that headspace analysis could be used for diagnosis of this particular cancer. In this paper, we evaluate the use of a commercially available gas sensor array coupled with a specifically designed pattern recognition algorithm for this purpose. The best diagnostic performance that we were able to obtain with independent test data provided by healthy volunteers and bladder cancer patients was 70% overall accuracy (70% sensitivity and 70% specificity). When the data of patients suffering from other non-cancerous urological diseases were added to those of the healthy controls, the classification accuracy fell to 65% with 60% sensitivity and 67% specificity. While this is not sufficient for a diagnostic test, it is significantly better than random chance, leading us to conclude that there is useful information in the urine headspace but that a more informative analytical technique, such as mass spectrometry, is required if this is to be exploited fully.Item Open Access An exploratory comparative study of volatile compounds in exhaled breath and emitted by skin using selected ion flow tube mass spectrometry(John Wiley & Sons, Ltd, 2008-01-01T00:00:00Z) Turner, Claire; Parekh, Bhavin; Walton, Christopher; Španěl, Patrik; Smith, David; Evans, MarkThis study examined the utilization patterns of key Carbon sources (CS, 24: including key sugars, aminoacids and fatty acids) in maize by strains of Aspergillus flavus and Fusarium verticillioides under different water activity (aw, 0.87-0.98 aw) and temperature (20-35°C) values and compared the niche overlap indices (NOI) that estimate the in vitro carbon source utilization profiles (Wilson and Lindow, 1994). The ability to grow in these key CS in minimal media was studied for 120 hrs in 12 hr steps. The NOI was calculated for inter-species (F. verticillioides – A. flavus) and for intra-species (A. flavus - A. flavus) using CS utilisation patterns over the range of interacting environmental conditions. 30°C, over the whole aw range examined, was found to be optimal for utilization of the maximum number of CS by A. flavus. In contrast, for F. verticillioides this was more so at 20°C; 25°C allowed a suboptimal usage of CS for both species. NOIs confirmed the nutritional dominance of A. flavus at 30°C, especially at lower aw levels and that of F. verticillioides at 20°C, mainly at 0.95 aw. In other conditions of aw, based on CS utilization patterns, the data indicated that A. flavus and F. verticillioides occupied different ecological niches. The variability in nutritional sources utilization between A. flavus strains was not related to their ability to produce aflatoxins (AFs). This type of data helps to explain the nutritional dominance of fungal species and strains under different environmental conditions. This could be useful in trying to find appropriate natural biocontrol microorganisms to compete with these mycotoxigenicItem Open Access Methodological variation in headspace analysis of liquid samples using electronic nose(Elsevier, 2009-06-04) Knobloch, Henri; Turner, Claire; Spooner, Andrew; Chambers, MarkIn past years, numerous electronic nose (e-nose) developments have been published describing analyses of solid-, liquid- or gaseous media in microbiological-, environmental-, agricultural- or medical applications. However, little has been reported about complex methodological pitfalls that might be associated with commercially available e-nose technology. In this paper, some of these pitfalls such as temperature, the use of filters and mass flow using different sampling methods (static- and dynamic sampling) are described for two generations of conducting polymer e-noses (ST114/214, CPs, both Scensive Tech. Ltd.). A comparison with metal oxide semiconducting field effect transistor/metal oxide semiconductor (MOSFET/MOS) e-noses regarding stability across replicates and over time was made. Changes in temperature were found to give larger sensor responses, whereas the application of filters led to quantitative and qualitative changes in sensor responses due to a change in mass flow which was also affected by the sampling method. Static sampling provided more stable flows across replicates. Variation was investigated for CPs and MOSFET/MOS e-noses that gave different responses over time and across replicates. These methodological factors cause a lack of stability and reproducibility, demonstrating the pitfalls of e-nose technology and therefore limit their utility for discriminating between samples.Item Open Access Optical assay for biotechnology and clinical diagnosis(IEEE Institute of Electrical and Electronics, 2011-12-31T00:00:00Z) Moczko, Ewa; Cauchi, Michael; Turner, Claire; Meglinski, I. V.; Piletsky, Sergey A.In this paper, we present an optical diagnostic assay consisting of a mixture of environmental-sensitive fluorescent dyes combined with multivariate data analysis for quantitative and qualitative examination of biological and clinical samples. The performance of the assay is based on the analysis of spectrum of the selected fluorescent dyes with the operational principle similar to electronic nose and electronic tongue systems. This approach has been successfully applied for monitoring of growing cell cultures and identification of gastrointestinal diseases in humans.Item Open Access Serum and urine headspace using electronic nose (e-nose) technology(Cranfield University, 2009-10-02) Knobloch, Henri; Turner, ClaireFor the last 20 years, several applications of electronic nose (e-nose) have been reported in the area of microbiology, environmental and agricultural monitoring or medical diagnosis. E-noses were used to detect contaminants or for quality control. However, little has been reported about complex methodological problems which are strongly linked to the e-nose performance. This thesis summarises various e-nose systems and alternatives for gas and headspace analysis, highlights the essential problems associated with e-nose analysis and explains why these devices have a potential for the detection of trace gas molecules but also why a stable and reliable analysis is not possible yet. Methodological weaknesses such as changes in mass flow rates, filter application or sampling methods are addressed. Understanding these enables analysis of serum and urine samples from cattle or badgers either naturally or experimentally infected with the zoonotic diseases caused by Mycoplasma bovis, Mannheimia haemolytica A1, Mycobacterium bovis, Mycobacterium avium ssp. paraTuberculosis and Brucella sp. The circumstances under which meaningful results can be obtained using the ST214 e-nose (Scensive Tech. Ltd., UK) are assessed which show the current limitations for discriminating between samples. Alternative methods for analysing e-nose data are mentioned and reasons are given why under the stated circumstances no straightforward multivariate statistics is possible. However, despite various difficulties, meaningful results at a group level were obtained and could be correlated with other results obtained using alternative analytical methods. This indicates the positive proof-of-principle character of this project.Item Open Access Understanding the fate and transport of petroleum hydrocarbons from coal tar within gasholders(Elsevier Science B.V., Amsterdam., 2009-02-28T00:00:00Z) Coulon, Frederic; Orsi, R.; Turner, Claire; Walton, Christopher; Daly, Paddy; Pollard, Simon J. T.Coal tars have been identified as posing a threat to human health due to their toxic, mutagenic and carcinogenic characteristics. Workers involved in former gasholders decommissioning are potentially exposed to relevant concentrations of volatile and semi-volatile hydrocarbons upon opening up derelict tanks and during tar excavation/removal. While information on contaminated sites air- quality and its implications on medium-long term exposure is available, acute exposure issues associated with the execution of critical tasks are less understood. Calculations indicated that the concentration of a given contaminant in the gasholder vapour phase only depends on the coal tar composition, being only barely affected by the presence of water in the gasholder and the tar volume/void space ratio. Fugacity modelling suggested that risk-critical compounds such as benzene, naphthalene and other monocyclic and polycyclic aromatic hydrocarbons may gather in the gasholder air phase at significant concentrations. Gasholder emissions were measured on-site and compared with the workplace exposure limits (WELs) currently in use in UK. While levels for most of the toxic compounds were far lower than WELs, benzene air-concentrations where found to be above the accepted threshold. In addition due to the long exposure periods involved in gasholder decommissioning and the significant contribution given by naphthalene to the total coal tar vapour concentration, the adoption of a WEL for naphthalene may need to be considered to support operators in preventing human health risk at the workplace. The Level I fugacity approach used in this study demonstrated its suitability for applications to sealed environments such as gasholders and its further refining could provide a useful tool for land remediation risk assessors. (C) 2008 Elsevier Ltd. All rights reserved.Item Open Access Use of the analysis of the volatile faecal metabolome in screening for colorectal cancer(Public Library of Science, 2015-06-18) Batty, Claire A.; Cauchi, Michael; Lourenço, Célia; Hunter, John O.; Turner, ClaireDiagnosis of colorectal cancer is an invasive and expensive colonoscopy, which is usually carried out after a positive screening test. Unfortunately, existing screening tests lack specificity and sensitivity, hence many unnecessary colonoscopies are performed. Here we report on a potential new screening test for colorectal cancer based on the analysis of volatile organic compounds (VOCs) in the headspace of faecal samples. Faecal samples were obtained from subjects who had a positive faecal occult blood sample (FOBT). Subjects subsequently had colonoscopies performed to classify them into low risk (non-cancer) and high risk (colorectal cancer) groups. Volatile organic compounds were analysed by selected ion flow tube mass spectrometry (SIFT-MS) and then data were analysed using both univariate and multivariate statistical methods. Ions most likely from hydrogen sulphide, dimethyl sulphide and dimethyl disulphide are statistically significantly higher in samples from high risk rather than low risk subjects. Results using multivariate methods show that the test gives a correct classification of 75% with 78% specificity and 72% sensitivity on FOBT positive samples, offering a potentially effective alternative to FOBT.