Browsing by Author "Barr, Hugh"

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    Lymph node pathology using optical spectroscopy in cancer diagnostics
    (2008-12-31T00:00:00Z) Isabelle, M.; Stone, N.; Barr, Hugh; Vipond, M.; Shepherd, N.; Rogers, Keith
    Raman and infrared spectroscopy are optical spectroscopic techniques that use light scattering (Raman) and light absorption (infrared) to probe the vibrational energy levels of molecules in tissue samples. Using these techniques, one can gain an insight into the biochemical composition of cells and tissues by looking at the spectra produced and comparing them with spectra obtained from standards such as proteins, nucleic acids, lipids and carbohydrates. As a result of optical spectroscopy being able to measure these biochemical changes, diagnosis of cancer could take place faster than current diagnostic methods, assisting and offering pathologists and cytologists a novel technology in cancer screening and diagnosis. The purpose of this study is to use both spectroscopic techniques, in combination with multivariate statistical analysis tools, to analyze some of the major biochemical and morphological changes taking place during carcinogenesis and metastasis in lymph nodes and to develop a predictive model to correctly differentiate cancerous from benign lymph nodes taken from oesophageal cancer patients. The results of this study showed that Raman and infrared spectroscopy managed to correctly differentiate between cancerous and benign oesophageal lymph nodes with a training performance greater than 94% using principal component analysis (PCA)fed linear discriminant analysis (LDA). Cancerous nodes had higher nucleic acid but lower lipid and carbohydrate content compared to benign nodes which is indicative of increased cell proliferation and loss of differentiation. With better understanding of the molecular mechanisms of carcinogenesis and metastasis together with use of multivariate statistical analysis tools, these spectroscopic studies will provide a platform for future development of real-time (in surgery) non-invasive diagnostic tools in medical research.
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    Use of volatile fingerprints for rapid screening of antifungal agents for efficacy against dermatophyte Trichophyton species
    (Elsevier Science B.V., Amsterdam., 2010-04-29T00:00:00Z) Naraghi, Kamran; Sahgal, Natasha; Adriaans, Beverley; Barr, Hugh; Magan, Naresh
    The potential of using an electronic nose (E-nose) as a rapid technique for screening the responses of dermatophytes to antifungal agents was studied. In vitro, the 50% and 90% effective concentration (EC) values of five antifungal agents including fungicides and antioxidant mixtures against Trichophyton rubrum and Trichophyton mentagrophytes were obtained by mycelial growth assays. The qualitative volatile production patterns of the growth responses of these fungi to the EC values incorporated into solid media were analysed after 96-120h incubation at 25°C using headspace analyses using five replicates per treatment. Overall, results, using principal components analysis and cluster analysis, demonstrated that it was possible to differentiate between various treatments within 96-120h of growth. The EC50 values were discriminated from the controls while the EC90 concentration treatments were often grouped with the agar blanks because of very slow growth. This study showed that potential exists for using qualitative volatile patterns as a rapid screening method for antifungal agents against micro-organisms. This approach could significantly improve and facilitate the monitoring of antimicrobial drug activities and infection control programmes and perhaps also for monitoring of drug resistance buildup in microbial populations