Publications
272 results found
Cheng Y, Li R, Li S, et al., 2012, SHEAR WAVE ELASTICITY IMAGING BASED ON ACOUSTIC RADIATION FORCE AND OPTICAL DETECTION, ULTRASOUND IN MEDICINE AND BIOLOGY, Vol: 38, Pages: 1637-1645, ISSN: 0301-5629
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- Citations: 18
Brown AC, Oddos S, Dobbie IM, et al., 2012, Correction: Remodelling of Cortical Actin Where Lytic Granules Dock at Natural Killer Cell Immune Synapses Revealed by Super-Resolution Microscopy., PLoS Biol, Vol: 10
[This corrects the article on p. e1001152 in vol. 9.].
Patalay R, Talbot C, Alexandrov Y, et al., 2012, Basal cell carcinoma evaluation and tumour margin assessment using multiphoton tomography and fluorescence lifetime imaging, 92nd Annual Meeting of the British-Association-of-Dermatologists, Publisher: WILEY-BLACKWELL, Pages: 78-79, ISSN: 0007-0963
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- Citations: 1
Patalay R, Chu A, Dunsby C, et al., 2012, A noninvasive imaging study of skin using two photon microscopy of cellular autofluorescence, 70th Annual Meeting of the American-Academy-of-Dermatology (AAD), Publisher: MOSBY-ELSEVIER, Pages: AB83-AB83, ISSN: 0190-9622
Thompson AJ, Coda S, Sorensen MB, et al., 2012, In vivo measurements of diffuse reflectance and time-resolved autofluorescence emission spectra of basal cell carcinomas, JOURNAL OF BIOPHOTONICS, Vol: 5, Pages: 240-254, ISSN: 1864-063X
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- Citations: 30
Seidenari S, Arginelli F, Bassoli S, et al., 2012, Multiphoton laser microscopy and fluorescence lifetime imaging for the evaluation of the skin., Dermatol Res Pract, Vol: 2012
Multiphoton laser microscopy is a new, non-invasive technique providing access to the skin at a cellular and subcellular level, which is based both on autofluorescence and fluorescence lifetime imaging. Whereas the former considers fluorescence intensity emitted by epidermal and dermal fluorophores and by the extra-cellular matrix, fluorescence lifetime imaging (FLIM), is generated by the fluorescence decay rate. This innovative technique can be applied to the study of living skin, cell cultures and ex vivo samples. Although still limited to the clinical research field, the development of multiphoton laser microscopy is thought to become suitable for a practical application in the next few years: in this paper, we performed an accurate review of the studies published so far, considering the possible fields of application of this imaging method and providing high quality images acquired in the Department of Dermatology of the University of Modena.
Patalay R, Talbot C, Alexandrov Y, et al., 2011, Quantification of cellular autofluorescence of human skin using multiphoton tomography and fluorescence lifetime imaging in two spectral detection channels, Biomedical Optics Express, Vol: 2, Pages: 3295-3308, ISSN: 2156-7085
We explore the diagnostic potential of imaging endogenous fluorophores using two photon microscopy and fluorescence lifetime imaging (FLIM) in human skin with two spectral detection channels. Freshly excised benign dysplastic nevi (DN) and malignant nodular Basal Cell Carcinomas (nBCCs) were excited at 760 nm. The resulting fluorescence signal was binned manually on a cell by cell basis. This improved the reliability of fitting using a double exponential decay model and allowed the fluorescence signatures from different cell populations within the tissue to be identified and studied. We also performed a direct comparison between different diagnostic groups. A statistically significant difference between the median mean fluorescence lifetime of 2.79 ns versus 2.52 ns (blue channel, 300-500 nm) and 2.08 ns versus 1.33 ns (green channel, 500-640 nm) was found between nBCCs and DN respectively, using the Mann-Whitney U test (p < 0.01). Further differences in the distribution of fluorescence lifetime parameters and inter-patient variability are also discussed.
Patalay R, Talbot C, Alexandrov Y, et al., 2011, Non-invasive imaging of skin cancer with fluorescence lifetime imaging using two photon tomography, Optics InfoBase Conference Papers
Multispectral fluorescence lifetime imaging (FLIM) using two photon microscopy as a non-invasive technique for the diagnosis of skin lesions is described. Skin contains fluorophores including elastin, keratin, collagen, FAD and NADH. This endogenous contrast allows tissue to be imaged without the addition of exogenous agents and allows the in vivo state of cells and tissues to be studied. A modified DermaInspect® multiphoton tomography system was used to excite autofluorescence at 760 nm in vivo and on freshly excised ex vivo tissue. This instrument simultaneously acquires fluorescence lifetime images in four spectral channels between 360-655 nm using time-correlated single photon counting and can also provide hyperspectral images. The multispectral fluorescence lifetime images were spatially segmented and binned to determine lifetimes for each cell by fitting to a double exponential lifetime model. A comparative analysis between the cellular lifetimes from different diagnoses demonstrates significant diagnostic potential. © 2011 SPIE-OSA.
Brown ACN, Oddos S, Dobbie IM, et al., 2011, Remodelling of cortical actin where lytic granules dock at natural killer cell immune synapses revealed by super-resolution microscopy, PLoS Biology, Vol: 9, Pages: 1-18, ISSN: 1544-9173
Natural Killer (NK) cells are innate immune cells that secrete lytic granules to directly kill virus-infected or transformed cells across an immune synapse. However, a major gap in understanding this process is in establishing how lytic granules pass through the mesh of cortical actin known to underlie the NK cell membrane. Research has been hampered by the resolution of conventional light microscopy, which is too low to resolve cortical actin during lytic granule secretion. Here we use two high-resolution imaging techniques to probe the synaptic organisation of NK cell receptors and filamentous (F)-actin. A combination of optical tweezers and live cell confocal microscopy reveals that microclusters of NKG2D assemble into a ring-shaped structure at the centre of intercellular synapses, where Vav1 and Grb2 also accumulate. Within this ring-shaped organisation of NK cell proteins, lytic granules accumulate for secretion. Using 3D-structured illumination microscopy (3D-SIM) to gain super-resolution of ∼100 nm, cortical actin was detected in a central region of the NK cell synapse irrespective of whether activating or inhibitory signals dominate. Strikingly, the periodicity of the cortical actin mesh increased in specific domains at the synapse when the NK cell was activated. Two-colour super-resolution imaging revealed that lytic granules docked precisely in these domains which were also proximal to where the microtubule-organising centre (MTOC) polarised. Together, these data demonstrate that remodelling of the cortical actin mesh occurs at the central region of the cytolytic NK cell immune synapse. This is likely to occur for other types of cell secretion and also emphasises the importance of emerging super-resolution imaging technology for revealing new biology.
Elson DS, Li R, Dunsby C, et al., 2011, Ultrasound-mediated optical tomography: a review of current methods, INTERFACE FOCUS, Vol: 1, Pages: 632-648, ISSN: 2042-8898
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- Citations: 60
Benati E, Bellini V, Borsari S, et al., 2011, Quantitative evaluation of healthy epidermis by means of multiphoton microscopy and fluorescence lifetime imaging microscopy, SKIN RESEARCH AND TECHNOLOGY, Vol: 17, Pages: 295-303, ISSN: 0909-752X
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- Citations: 34
Talbot CB, Patalay R, Munro I, et al., 2011, Application of ultrafast gold luminescence to measuring the instrument response function for multispectral multiphoton fluorescence lifetime imaging, OPTICS EXPRESS, Vol: 19, Pages: 13848-13861, ISSN: 1094-4087
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- Citations: 27
Talbot CB, Patalay R, Munro I, et al., 2011, Application of ultrafast gold luminescence to measuring the instrument response function for multispectral multiphoton fluorescence lifetime imaging., Opt Express, Vol: 19, Pages: 13848-13861
When performing multiphoton fluorescence lifetime imaging in multiple spectral emission channels, an instrument response function must be acquired in each channel if accurate measurements of complex fluorescence decays are to be performed. Although this can be achieved using the reference reconvolution technique, it is difficult to identify suitable fluorophores with a mono-exponential fluorescence decay across a broad emission spectrum. We present a solution to this problem by measuring the IRF using the ultrafast luminescence from gold nanorods. We show that ultrafast gold nanorod luminescence allows the IRF to be directly obtained in multiple spectral channels simultaneously across a wide spectral range. We validate this approach by presenting an analysis of multispectral autofluorescence FLIM data obtained from human skin ex vivo.
Kumar S, Wilding D, Sikkel MB, et al., 2011, High-speed 2D and 3D fluorescence microscopy of cardiac myocytes, OPTICS EXPRESS, Vol: 19, Pages: 13839-13847, ISSN: 1094-4087
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- Citations: 49
Coda S, Kennedy GT, Thompson A, et al., 2011, FLUORESCENCE LIFETIME IMAGING FOR LABEL-FREE CONTRAST OF GASTROINTESTINAL DISEASES, International School of Physics "Enrico Fermi", Course CLXXXI "Microscopy Applied to Biophotonics"
INTRODUCTION: Autofluorescence (AF) has been used to distinguish between normal and diseased tissue, but its molecular basis is still unclear and making quantitative intensity measurements is challenging. Fluorescence lifetime imaging (FLIM) measures the decay rate of the autofluorescent signal from tissue, providing quantitative AF contrast. FLIM has been recently implemented by our group in three endoscopic instruments consisting of a confocal laser endomicroscope, a wide-field fibre-optic endoscope and a single point fibre-optic probe. FLIM has the potential to report on tissue structure and function in real-time during endoscopy, providing a label-free means to detect the early onset of diseases that cause changes in tissue AF. We are developing these 3 modalities for in vivo clinical application, supported by ex vivo studies on freshly-biopsied/resected GI tissues.AIMS & METHODS: The aim of this work is to translate our FLIM instrumentation from the optical bench to in vivo clinical application. AF from 43 endoscopic samples from different GI sites was excited using a conventional confocal FLIM microscope in the range 405-420nm, which is compatible with our FLIM endoscopes, and which is the range needed to excite a number of important endogenous GI tissue fluorophores such as porphyrins, flavins, collagen and elastin. The samples were collected from patients undergoing endoscopy, transported to the FLIM laboratory to be imaged and then submitted for histopathology. The following disorders were investigated: Barrett’s oesophagus, gastric cancer, ulcerative colitis, Crohn’s disease, adenomatous polyps and colon cancer. The accuracy of FLIM in discriminating dysplastic/cancerous samples from normal tissue has been tested by measuring the Area Under the Curve (AUC).RESULTS: Our preliminary data show that premalignant or neoplastic samples display either shorter or longer fluorescence lifetime than that of normal tissue. Increased lifetime val
Coda S, Kennedy G, Thompson A, et al., 2011, FLUORESCENCE LIFETIME IMAGING OF GASTROINTESTINAL CANCERS, European-Society-for-Medical-Oncology (ESMO) 13th World Congress on Gastrointestinal Cancer, Publisher: OXFORD UNIV PRESS, Pages: v65-v66, ISSN: 0923-7534
Thompson AJ, Paterson C, Neil MAA, et al., 2011, Adaptive phase compensation for ultracompact laser scanning endomicroscopy, OPTICS LETTERS, Vol: 36, Pages: 1707-1709, ISSN: 0146-9592
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- Citations: 68
Li R, Elson DS, Dunsby C, et al., 2011, Effects of acoustic radiation force and shear waves for absorption and stiffness sensing in ultrasound modulated optical tomography., Opt Express, Vol: 19, Pages: 7299-7311
Ultrasound-modulated optical tomography (UOT) combines optical contrast with ultrasound spatial resolution and has great potential for soft tissue functional imaging. One current problem with this technique is the weak optical modulation signal, primarily due to strong optical scattering in diffuse media and minimal acoustically induced modulation. The acoustic radiation force (ARF) can create large particle displacements in tissue and has been shown to be able to improve optical modulation signals. However, shear wave propagation induced by the ARF can be a significant source of nonlocal optical modulation which may reduce UOT spatial resolution and contrast. In this paper, the time evolution of shear waves was examined on tissue mimicking-phantoms exposed to 5 MHz ultrasound and 532 nm optical radiation and measured with a CCD camera. It has been demonstrated that by generating an ARF with an acoustic burst and adjusting both the timing and the exposure time of the CCD measurement, optical contrast and spatial resolution can be improved by ~110% and ~40% respectively when using the ARF rather than 5 MHz ultrasound alone. Furthermore, it has been demonstrated that this technique simultaneously detects both optical and mechanical contrast in the medium and the optical and mechanical contrast can be distinguished by adjusting the CCD exposure time.
Grippon S, Zhao Q, Robinson T, et al., 2011, Differential modes of DNA binding by mismatch uracil DNA glycosylase from Escherichia coli: implications for abasic lesion processing and enzyme communication in the base excision repair pathway, Nucleic Acids Research, Vol: 39, Pages: 2593-2603, ISSN: 1362-4962
Mismatch uracil DNA glycosylase (Mug) fromEscherichia coli is an initiating enzyme in thebase-excision repair pathway. As with other DNAglycosylases, the abasic product is potentiallymore harmful than the initial lesion. Since Mug isknown to bind its product tightly, inhibitingenzyme turnover, understanding how Mug bindsDNA is of significance when considering how Muginteracts with downstream enzymes in the baseexcisionrepair pathway. We have demonstrateddifferential binding modes of Mug between its substrateand abasic DNA product using both band shiftand fluorescence anisotropy assays. Mug binds itsproduct cooperatively, and a stoichiometric analysisof DNA binding, catalytic activity and saltdependenceindicates that dimer formation is offunctional significance in both catalytic activity andproduct binding. This is the first report ofcooperativity in the uracil DNA glycosylase superfamilyof enzymes, and forms the basis of productinhibition in Mug. It therefore provides a new perspectiveon abasic site protection and the findingsare discussed in the context of downstream lesionprocessing and enzyme communication in the baseexcision repair pathway.
Everett KL, Buehler A, Bunney TD, et al., 2011, Membrane Environment Exerts an Important Influence on Rac-Mediated Activation of Phospholipase Cγ2, MOLECULAR AND CELLULAR BIOLOGY, Vol: 31, Pages: 1240-1251, ISSN: 0270-7306
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- Citations: 21
Kumar S, Alibhai D, Margineanu A, et al., 2011, FLIM FRET technology for drug discovery: automated multiwell-plate high-content analysis, multiplexed readouts and application in situ, ChemPhysChem: a European journal of chemical physics and physical chemistry, Vol: 12, Pages: 609-626, ISSN: 1439-4235
A fluorescence lifetime imaging (FLIM) technology platform intendedto read out changes in Fçrster resonance energy transfer(FRET) efficiency is presented for the study of protein interactionsacross the drug-discovery pipeline. FLIM provides arobust, inherently ratiometric imaging modality for drug discoverythat could allow the same sensor constructs to betranslated from automated cell-based assays through smalltransparent organisms such as zebrafish to mammals. To thisend, an automated FLIM multiwell-plate reader is described forhigh content analysis of fixed and live cells, tomographic FLIMin zebrafish and FLIM FRET of live cells via confocal endomicroscopy.For cell-based assays, an exemplar application readingout protein aggregation using FLIM FRET is presented, andthe potential for multiple simultaneous FLIM (FRET) readoutsin microscopy is illustrated.
Galletly N, McGinty J, Munro I, et al., 2011, Fluorescence lifetime imaging of liver cancer, 107th Annual Meeting of the American-Gastroenterlogical Association, Publisher: W B Saunders Co-Elsevier Inc
Margineanu A, Laine R, Kumar S, et al., 2011, Multiplexed Time Lapse Fluorescence Lifetime Readouts in an Optically Sectioning Time-Gated Imaging Microscope, 55th Annual Meeting of the Biophysical-Society, Publisher: CELL PRESS, Pages: 183-183, ISSN: 0006-3495
Thompson A, Manning H, Brydegaard M, et al., 2011, Hyperspectral fluorescence lifetime fibre probe spectroscopy for use in the study and diagnosis of osteoarthritis and skin cancer, SPIE Photonics West 2011, Publisher: Society of Photo-optical Instrumentation Engineers (SPIE), ISSN: 1996-756X
We present the application of two fibre-optic-coupled time-resolved spectrofluorometers and a compact steady-state diffuse reflected light/fluorescence spectrometer to in vivo and ex vivo studies of skin cancer and osteoarthritis. In a clinical study of skin cancer, 27 lesions on 25 patients were investigated in vivo before surgical excision of the region measured. Preliminary analysis reveals a statistically significant decrease in the autofluorescence lifetime of basal cell carcinomas compared to neighbouring healthy tissue. A study of autofluorescence signals associated with the onset of osteoarthritis indicates autofluorescence lifetime changes associated with collagen degradation.
Ushakov DS, Caorsi V, Ibanez-Garcia D, et al., 2011, Response of Rigor Cross-bridges to Stretch Detected by Fluorescence Lifetime Imaging Microscopy of Myosin Essential Light Chain in Skeletal Muscle Fibers, JOURNAL OF BIOLOGICAL CHEMISTRY, Vol: 286, Pages: 842-850
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- Citations: 11
Kumar S, Wilding D, Sikkel MB, et al., 2011, Application of oblique plane microscopy to high speed live cell imaging, Conference on Advanced Microscopy Techniques II, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
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- Citations: 1
Alibhai D, Kumar S, Kelly D, et al., 2011, An automated wide-field, time-gated, optically sectioning, fluorescence lifetime imaging multiwell plate reader for high-content analysis of protein-protein interactions, Conference on Three-Dimensional and Multidimensional Microscopy - Image Acquisition and Processing XVIII, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
Kumar S, Lin Z, Lyon AR, et al., 2011, Optically Sectioned Imaging by Oblique Plane Microscopy, Conference on Three-Dimensional and Multidimensional Microscopy - Image Acquisition and Processing XVIII, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
Kennedy GT, Coda S, Thompson AJ, et al., 2011, Fluorescence Lifetime Imaging Endoscopy, Conference on Endoscopic Microscopy VI, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
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- Citations: 3
Lenz MO, Brown ACN, Auksorius E, et al., 2011, A STED-FLIM microscope applied to imaging the Natural Killer cell immune synapse, Conference on Multiphoton Microscopy in the Biomedical Sciences XI, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
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- Citations: 5
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