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A Novel Method of Evaluating Ureteropelvic Junction Obstruction: Dynamic Near Infrared Fluorescence Imaging Compared to Standard Modalities to Assess Urinary Obstruction in a Swine Model

Rowe, Courtney K.; Franco, Felipe B.; Barbosa, Joao A. B. A.; Minnillo, Brian J.; Chow, Jeanne S.; Treves, Ted; Retik, Alan B.; Nguyen, Hiep T.
Fonte: ELSEVIER SCIENCE INC; NEW YORK Publicador: ELSEVIER SCIENCE INC; NEW YORK
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
57.58309%
Purpose: Dynamic near infrared fluorescence imaging of the urinary tract provides a promising way to diagnose ureteropelvic junction obstruction. Initial studies demonstrated the ability to visualize urine flow and peristalsis in great detail. We analyzed the efficacy of near infrared imaging in evaluating ureteropelvic junction obstruction, renal involvement and the anatomical detail provided compared to conventional imaging modalities. Materials and Methods: Ten swine underwent partial or complete unilateral ureteral obstruction. Groups were survived for the short or the long term. Imaging was performed with mercaptoacetyltriglycine diuretic renogram, magnetic resonance urogram, excretory urogram, ultrasound and near infrared imaging. Scoring systems for ureteropelvic junction obstruction were developed for magnetic resonance urogram and near infrared imaging. Physicians and medical students graded ureteropelvic junction obstruction based on magnetic resonance urogram and near infrared imaging results. Results: Markers of vascular and urinary dynamics were quantitatively consistent among control renal units. The same markers were abnormal in obstructed renal units with significantly different times of renal phase peak, start of pelvic phase and start of renal uptake. Such parameters were consistent with those obtained with mercaptoacetyltriglycine diuretic renography. Near infrared imaging provided live imaging of urinary flow...

Desenvolvimento de um sistema por imagem de fluorescência óptica para uso médico-odontológico; Development of an optical fluorescence imaging system for medical use

Costa, Mardoqueu Martins da
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 12/02/2010 PT
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57.396855%
A técnica de fluorescência óptica tem sido aplicada em diversas áreas médicas, como no acompanhamento da degradação de drogas e na detecção de câncer, por apresentar alta sensibilidade, simplicidade e rapidez na obtenção de dados. A avaliação não-invasiva e não-destrutiva é um grande atrativo que esta técnica oferece para o diagnóstico clínico. Assim, o objetivo deste projeto consistiu no desenvolvimento de um sistema de fluorescência óptica por imagem de campo amplo e avaliação do sistema no monitoramento da fotodegradação da Protoporfirina XI, utilizada na Terapia Fotodinâmica (TFD), e na visualização da presença de microrganismos presentes na microbiota bucal. O sistema desenvolvido é constituído de um sistema óptico, mecânico, eletrônico e de detecção. O sistema óptico é composto por LEDs de alta intensidade, com emissão centrada em 405nm e 450nm e 3 filtros ópticos: 1. passa-banda: utilizado na excitação; 2. dicróico; e 3. passa-alta: utilizados para excitação e emissão da fluorescência. O sistema mecânico foi desenvolvido em alumínio, possuindo as funções de dissipação de calor do sistema de iluminação e estrutural. O sistema eletrônico possui a função de controle e fornecimento de energia ao sistema de iluminação. O sistema de detecção é composto por uma câmera CCD e fotográfica...

Uso de imagens de fluorescência para monitoramento da evolução do cancro cítrico; Use of fluorescence imaging for monitoring the evolution of citrus canker

Wetterich, Caio Bruno
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 29/02/2012 PT
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57.11091%
A doença cancro cítrico é considerada uma das mais importantes doenças da citricultura devido ao seu poder de proliferação nas fazendas, e aos danos causados às plantas e frutos. Os prejuízos causados pela presença da doença são consideravelmente preocupantes, pois as principais medidas de controle pelos órgãos responsáveis envolvem a erradicação de plantas infectadas e demais plantas vizinhas, inviabilizando economicamente grandes áreas produtivas. A legislação brasileira exige um extenso protocolo de atividades que necessita ser realizado antes da confirmação do diagnóstico. Atrasos na confirmação do diagnóstico favorecem a proliferação da doença. Assim, qualquer esforço em acelerar esta detecção deve com certeza ter um grande impacto nesta área. Esta é a motivação de nosso trabalho, onde aplicamos a técnica de espectroscopia por imagens de fluorescência em folhas de culturas cítricas com a intenção de avaliar a capacidade de diagnóstico desta técnica em plantas assintomáticas contaminadas no laboratório com cancro cítrico. O objetivo é determinar o instante de tempo mínimo necessário entre a infecção e o diagnóstico preciso da doença. Este estudo foi aplicado para experimentos envolvendo amostras destrutivas e não-destrutivas. Os resultados mostram a possibilidade de aplicar tal técnica na detecção de cancro cítrico.; The citrus canker disease is considered one of the most important citrus diseases due to its ability to spread on farms...

Fluorescence Imaging of Two-Photon Linear Dichroism: Cholesterol Depletion Disrupts Molecular Orientation in Cell Membranes

Benninger, Richard K. P.; Önfelt, Björn; Neil, Mark A. A.; Davis, Daniel M.; French, Paul M. W.
Fonte: The Biophysical Society Publicador: The Biophysical Society
Tipo: Artigo de Revista Científica
EN
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57.21833%
The plasma membrane of cells is an ordered environment, giving rise to anisotropic orientation and restricted motion of molecules and proteins residing in the membrane. At the same time as being an organized matrix of defined structure, the cell membrane is heterogeneous and dynamic. Here we present a method where we use fluorescence imaging of linear dichroism to measure the orientation of molecules relative to the cell membrane. By detecting linear dichroism as well as fluorescence anisotropy, the orientation parameters are separated from dynamic properties such as rotational diffusion and homo energy transfer (energy migration). The sensitivity of the technique is enhanced by using two-photon excitation for higher photo-selection compared to single photon excitation. We show here that we can accurately image lipid organization in whole cell membranes and in delicate structures such as membrane nanotubes connecting two cells. The speed of our wide-field imaging system makes it possible to image changes in orientation and anisotropy occurring on a subsecond timescale. This is demonstrated by time-lapse studies showing that cholesterol depletion rapidly disrupts the orientation of a fluorophore located within the hydrophobic region of the cell membrane but not of a surface bound probe. This is consistent with cholesterol having an important role in stabilizing and ordering the lipid tails within the plasma membrane.

Simultaneous Measurement of Water Volume and pH in Single Cells Using BCECF and Fluorescence Imaging Microscopy

Alvarez-Leefmans, Francisco J.; Herrera-Pérez, José J.; Márquez, Martín S.; Blanco, Víctor M.
Fonte: Biophysical Society Publicador: Biophysical Society
Tipo: Artigo de Revista Científica
EN
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57.14322%
Regulation and maintenance of cell water volume and intracellular pH (pHi) are vital functions that are interdependent; cell volume regulation affects, and is in turn affected by, changes in pHi. Disruption of either function underlies various pathologies. To study the interaction and kinetics of these two mechanisms, we developed and validated a quantitative fluorescence imaging microscopy method to measure simultaneous changes in pHi and volume in single cells loaded with the fluorescent probe BCECF. CWV is measured at the excitation isosbestic wavelength, whereas pHi is determined ratiometrically. The method has a time resolution of <1 s and sensitivity to osmotic changes of ∼1%. It can be applied in real time to virtually any cell type attached to a coverslip, independently of cellular shape and geometry. Calibration procedures and algorithms developed to transform fluorescence signals into changes in cell water volume (CWV) and examples of applications are presented.

In Situ Background Estimation in Quantitative Fluorescence Imaging

Chen, Tsai-Wen; Lin, Bei-Jung; Brunner, Edgar; Schild, Detlev
Fonte: Biophysical Society Publicador: Biophysical Society
Tipo: Artigo de Revista Científica
EN
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57.21833%
Fluorescence imaging of bulk-stained tissue is a popular technique for monitoring the activities in a large population of cells. However, a precise quantification of such experiments is often compromised by an ambiguity of background estimation. Although, in single-cell-staining experiments, background can be measured from a neighboring nonstained region, such a region often does not exist in bulk-stained tissue. Here we describe a novel method that overcomes this problem. In contrast to previous methods, we determined the background of a given region of interest (ROI) using the information contained in the temporal dynamics of its individual pixels. Since no information outside the ROI is needed, the method can be used regardless of the staining profile in the surrounding tissue. Moreover, we extend the method to deal with background inhomogeneities within a single ROI, a problem not yet solved by any of the currently available tools. We performed computer simulations to demonstrate the accuracy of our method and give example applications in ratiometric calcium imaging of bulk-stained olfactory bulb slices. Converting the fluorescence signals into [Ca2+] gives resting values consistent with earlier single-cell staining results, and odorant-induced [Ca2+] transients can be quantitatively compared in different cells. Using these examples we show that inaccurate background subtraction introduces large errors (easily in the range of 100%) in the assessment of both resting [Ca2+] and [Ca2+] dynamics. The proposed method allows us to avoid such errors.

Fluorescence imaging of vascular endothelial growth factor in tumors for mice embedded in a turbid medium

Biswal, Nrusingh C.; Gamelin, John K.; Yuan, Baohong; Backer, Marina V.; Backer, Joseph M.; Zhu, Quing
Fonte: Society of Photo-Optical Instrumentation Engineers Publicador: Society of Photo-Optical Instrumentation Engineers
Tipo: Artigo de Revista Científica
EN
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57.21833%
We demonstrate the feasibility of fluorescence imaging of deeply seated tumors using mice injected with an angiogenesis tracer, a vascular endothelial growth factor conjugated with the infrared dye cyanine 7 (VEGF∕Cy7). Our optical-only imaging reconstruction method separately estimates the target depth, and then applies this information to reconstruct functional information such as fluorophore concentration. Fluorescence targets with concentrations as low as sub-25 nM are well reconstructed at depths up to 2 cm in both homogeneous and heterogeneous media with this technique.

Multispectral fluorescence imaging to assess pH in biological specimens

Hight, Matthew R.; Nolting, Donald D.; McKinley, Eliot T.; Lander, Adam D.; Wyatt, Shelby K.; Gonyea, Mark; Zhao, Ping; Manning, H. Charles
Fonte: Society of Photo-Optical Instrumentation Engineers (SPIE) Publicador: Society of Photo-Optical Instrumentation Engineers (SPIE)
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
57.358965%
Simple, quantitative assays to measure pH in tissue could improve the study of complicated biological processes and diseases such as cancer. We evaluated multispectral fluorescence imaging (MSFI) to quantify extracellular pH (pHe) in dye-perfused, surgically-resected tumor specimens with commercially available instrumentation. Utilizing a water-soluble organic dye with pH-dependent fluorescence emission (SNARF-4F), we used standard fluorimetry to quantitatively assess the emission properties of the dye as a function of pH. By conducting these studies within the spectroscopic constraints imposed by the appropriate imaging filter set supplied with the imaging system, we determined that correction of the fluorescence emission of deprotonated dye was necessary for accurate determination of pH due to suboptimal excitation. Subsequently, employing a fluorimetry-derived correction factor (CF), MSFI data sets of aqueous dye solutions and tissuelike phantoms could be spectrally unmixed to accurately quantify equilibrium concentrations of protonated (HA) and deprotonated (A−) dye and thus determine solution pH. Finally, we explored the feasibility of MSFI for high-resolution pHe mapping of human colorectal cancer cell-line xenografts. Data presented suggest that MSFI is suitable for quantitative determination of pHe in ex vivo dye-perfused tissue...

Quantitative fluorescence imaging of protoporphyrin IX through determination of tissue optical properties in the spatial frequency domain

Saager, Rolf B.; Cuccia, David J.; Saggese, Steve; Kelly, Kristen M.; Durkin, Anthony J.
Fonte: Society of Photo-Optical Instrumentation Engineers (SPIE) Publicador: Society of Photo-Optical Instrumentation Engineers (SPIE)
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
57.368877%
The ability to quantitatively determine tissue fluorescence is of interest for the purpose of better understanding the details of photodynamic therapy of skin cancer. In particular, we are interested in quantifying protoporphyrin IX (PpIX) in vivo. We present a method of correcting fluorescence for effects of native tissue absorption and scattering properties in a spatially resolved manner that preserves the resolution of the fluorescence imaging system, based off a homogeneous representation of tissue. Validation was performed using a series of liquid turbid phantoms having varying concentrations of absorber, scatterer, and fluorophore (PpIX). Through the quantification of tissue optical properties via spatial frequency domain imaging, an empirical model based on Monte Carlo simulations was deployed to successfully decouple the effects of absorption and scattering from fluorescence. From this we were able to deduce the concentration of the PpIX to within 0.2 μg/ml of the known concentration. This method was subsequently applied to the determination of PpIX concentration from in vivo normal skin where the model-based correction determined a concentration of 1.6 μg/ml, which is in agreement with literature.

Improved tumor contrast achieved by single time point dual-reporter fluorescence imaging

Tichauer, Kenneth M.; Samkoe, Kimberley S.; Sexton, Kristian J.; Gunn, Jason R.; Hasan, Tayyaba; Pogue, Brian W.
Fonte: Society of Photo-Optical Instrumentation Engineers Publicador: Society of Photo-Optical Instrumentation Engineers
Tipo: Artigo de Revista Científica
EN
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57.33375%
In this study, we demonstrate a method to quantify biomarker expression that uses an exogenous dual-reporter imaging approach to improve tumor signal detection. The uptake of two fluorophores, one nonspecific and one targeted to the epidermal growth factor receptor (EGFR), were imaged at 1 h in three types of xenograft tumors spanning a range of EGFR expression levels (n=6 in each group). Using this dual-reporter imaging methodology, tumor contrast-to-noise ratio was amplified by >6 times at 1 h postinjection and >2 times at 24 h. Furthermore, by as early as 20 min postinjection, the dual-reporter imaging signal in the tumor correlated significantly with a validated marker of receptor density (P<0.05, r=0.93). Dual-reporter imaging can improve sensitivity and specificity over conventional fluorescence imaging in applications such as fluorescence-guided surgery and directly approximates the receptor status of the tumor, a measure that could be used to inform choices of biological therapies.

Modular video endoscopy for in vivo cross-polarized and vital-dye fluorescence imaging of Barrett’s-associated neoplasia

Thekkek, Nadhi; Pierce, Mark C.; Lee, Michelle H.; Polydorides, Alexandros D.; Flores, Raja M.; Anandasabapathy, Sharmila; Richards-Kortum, Rebecca R.
Fonte: Society of Photo-Optical Instrumentation Engineers Publicador: Society of Photo-Optical Instrumentation Engineers
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
57.227134%
A modular video endoscope is developed and tested to allow imaging in different modalities. This system incorporates white light imaging (WLI), cross-polarized imaging (CPI), and vital-dye fluorescence imaging (VFI), using interchangeable filter modules. CPI and VFI are novel endoscopic modalities that probe mucosal features associated with Barrett’s neoplasia. CPI enhances vasculature, while VFI enhances glandular architecture. In this pilot study, we demonstrate the integration of these modalities by imaging areas of Barrett’s metaplasia and neoplasia in an esophagectomy specimen. We verify that those key image features are also observed during an in vivo surveillance procedure. CPI images demonstrate improved visualization of branching blood vessels associated with neoplasia. VFI images show glandular architecture with increased glandular effacement associated with neoplasia. Results suggests that important pathologic features seen in CPI and VFI are not visible during standard endoscopic white light imaging, and thus the modalities may be useful in future in vivo studies for discriminating neoplasia from Barrett’s metaplasia. We further demonstrate that the integrated WLI/CPI/VFI endoscope is compatible with complementary high-resolution endomicroscopy techniques such as the high-resolution microendoscope...

Self-interference fluorescence microscopy: three dimensional fluorescence imaging without depth scanning

de Groot, Mattijs; Evans, Conor L.; de Boer, Johannes F.
Fonte: Optical Society of America Publicador: Optical Society of America
Tipo: Artigo de Revista Científica
EN_US
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57.293765%
We present a new method for high-resolution, three-dimensional fluorescence imaging. In contrast to beam-scanning confocal microscopy, where the laser focus must be scanned both laterally and axially to collect a volume, we obtain depth information without the necessity of depth scanning. In this method, the emitted fluorescence is collected in the backward direction and is sent through a phase plate that encodes the depth information into the phase of a spectrally resolved interference pattern. We demonstrate that decoding this phase information allows for depth localization accuracy better than 4 µm over a 500 µm depth-of-field. In a high numerical aperture configuration with a much smaller depth of field, a localization accuracy of tens of nanometers can be achieved. This approach is ideally suited for miniature endoscopes, where space limitations at the endoscope tip render depth scanning difficult. We illustrate the potential for 3D visualization of complex biological samples by constructing a three-dimensional volume of the microvasculature of ex vivo murine heart tissue from a single 2D scan.

Two-photon fluorescence imaging of intracellular hydrogen peroxide with chemoselective fluorescent probes

Guo, Hengchang; Aleyasin, Hossein; Howard, Scott S.; Dickinson, Bryan C.; Lin, Vivian S.; Haskew-Layton, Renee E.; Xu, Chris; Chen, Yu; Ratan, Rajiv R.
Fonte: Society of Photo-Optical Instrumentation Engineers Publicador: Society of Photo-Optical Instrumentation Engineers
Tipo: Artigo de Revista Científica
EN_US
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57.355493%
Abstract. We present the application of two-photon fluorescence (TPF) imaging to monitor intracellular hydrogen peroxide (H2O2) production in brain cells. For selective imaging of H2O2 over other reactive oxygen species, we employed small-molecule fluorescent probes that utilize a chemoselective boronate deprotection mechanism. Peroxyfluor-6 acetoxymethyl ester detects global cellular H2O2 and mitochondria peroxy yellow 1 detects mitochondrial H2O2. Two-photon absorption cross sections for these H2O2 probes are measured with a mode-locked Ti:sapphire laser in the wavelength range of 720 to 1040 nm. TPF imaging is demonstrated in the HT22 cell line to monitor both cytoplasmic H2O2 and localized H2O2 production in mitochondria. Endogenous cytoplasmic H2O2 production is detected with TPF imaging in rat astrocytes modified with d-amino acid oxidase. The TPF H2O2 imaging demonstrated that these chemoselective probes are powerful tools for the detection of intracellular H2O2.

U-SPECT-BioFluo: an integrated radionuclide, bioluminescence, and fluorescence imaging platform

van Oosterom, Matthias N; Kreuger, Rob; Buckle, Tessa; Mahn, Wendy A; Bunschoten, Anton; Josephson, Lee; van Leeuwen, Fijs WB; Beekman, Freek J
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
EN_US
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67.626616%
Background: In vivo bioluminescence, fluorescence, and single-photon emission computed tomography (SPECT) imaging provide complementary information about biological processes. However, to date these signatures are evaluated separately on individual preclinical systems. In this paper, we introduce a fully integrated bioluminescence-fluorescence-SPECT platform. Next to an optimization in logistics and image fusion, this integration can help improve understanding of the optical imaging (OI) results. Methods: An OI module was developed for a preclinical SPECT system (U-SPECT, MILabs, Utrecht, the Netherlands). The applicability of the module for bioluminescence and fluorescence imaging was evaluated in both a phantom and in an in vivo setting using mice implanted with a 4 T1-luc + tumor. A combination of a fluorescent dye and radioactive moiety was used to directly relate the optical images of the module to the SPECT findings. Bioluminescence imaging (BLI) was compared to the localization of the fluorescence signal in the tumors. Results: Both the phantom and in vivo mouse studies showed that superficial fluorescence signals could be imaged accurately. The SPECT and bioluminescence images could be used to place the fluorescence findings in perspective...

X-ray fluorescence imaging of single human cancer cells reveals that the N-heterocyclic ligands of iodinated analogues of ruthenium anticancer drugs remain coordinated after cellular uptake

Antony, S.; Aitken, J.; Vogt, S.; Lai, B.; Brown, T.; Spiccia, L.; Harris, H.
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
Publicado em //2013 EN
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67.14322%
Analogues of KP1019 containing iodinated indazole ligands were prepared to investigate the biological fate of the Ru-N-heterocycle bond in this class of anticancer agents. The new complexes, 5-iodoindazolium trans-tetrachloridobis(5-iodoindazole)ruthen(III)ate (1) and 5-iodoindazolium trans-tetrachlorido(dimethyl sulfoxide)(5-iodoindazole)ruthen(III)ate (3), were characterized by elemental analysis, mass spectrometry and UV-vis spectrophotometry. Tetramethylammonium salts of these complexes (2 and 4) were synthesized and characterized in a similar manner. Half-maximum inhibitory concentrations of 2 and 4 with regard to A549 cells at 24 h were determined on the basis of the dose-response curves derived from real-time cell adhesion impedance measurements and were shown to be in the same range as those determined for KP1019 and NAMI-A using the same method. X-ray fluorescence imaging of single cultured A549 cells treated with 2 or 4 showed that, in both cases, the distribution of ruthenium and iodine was identical, indicating that the Ru-N bonds in the anionic complexes remained intact after incubation in culture medium and subsequent cellular uptake and processing.; Sumy Antony, Jade B. Aitken, Stefan Vogt, Barry Lai, Tracey Brown, Leone Spiccia...

Optical Imaging Techniques for the Detection of Esophageal Neoplasia in Barrett’s Esophagus

Thekkek, Nadhi
Fonte: Universidade Rice Publicador: Universidade Rice
Tipo: Thesis; Text Formato: application/pdf
ENG
Relevância na Pesquisa
57.28004%
The main objective of this research was to develop a two-stage optical imaging platform to improve detection of cancer in Barrett’s esophagus (BE). BE caused by chronic reflux and patients with BE are at a higher risk for developing esophageal adenocarcinoma (EAC). However, neoplasia in BE is often unidentifiable under standard endoscopy, and studies have shown nearly half of early cancers can go unidentified by this method. Widefield imaging (resolves ~100 microns) allows efficient surveillance of large BE segments. Two widefield imaging techniques were identified to improve contrast between benign and abnormal lesions during an ex vivo 15 patient feasibility study. Cross-polarized imaging (CPI) reduced specular reflection and improved vascular contrast. Vital-dye fluorescence imaging (VFI) using topically-applied proflavine improved visualization of glandular pattern. Moreover, relevant pathologic features visible during VFI were seen in corresponding histology slides as well as high resolution images of the same sites. Based on these results, a cap-based Multispectral Digital Endoscope (MDE) was designed and built. The MDE can image in three different imaging modes: white light imaging, CPI, and VFI. Modifications to a Pentax EPK-i video processor and a Pentax endoscope were made to incorporate these imaging modes into one system. A 21 patient in vivo pilot study with 65 pathologically correlated sites demonstrated the feasibility of using this system in vivo; image criteria were developed to classify neoplasia with a sensitivity and specificity of 100% and 76% respectively. High resolution imaging (resolves ~2-5 micron) may verify the disease presence in suspicious areas identified using widefield techniques. 2-NBDG...

Spectrally resolved multidepth fluorescence imaging

Luo, Yuan; Zervantonakis, Ioannis K.; Oh, Se Baek; Kamm, Roger D.; Barbastathis, George
Fonte: Society of Photo-Optical Instrumentation Engineers (SPIE) Publicador: Society of Photo-Optical Instrumentation Engineers (SPIE)
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
57.269214%
We present a multicolor fluorescence imaging modality to visualize in real-time tissue structures emitting multispectral fluorescent light from different focal depths. Each designated spectrum of fluorescent emission from a specific depth within a volumetric tissue is probed by a depth-spectrum selective holographic grating. The grating for each fluorescent color are multiplexed within a volume hologram, which enables simultaneously obtaining multicolored fluorescent information at different depths within a biological tissue sample. We demonstrate the imaging modality's ability to obtain laser-induced multicolored fluorescence images of a biological sample from different depths without scanning. We also experimentally demonstrate that the imaging modality can be simultaneously operated at both fluorescent and bright field modes to provide complementary information of volumetric tissue structures at different depths in real-time.

Developing an imaging bi-spectrometer for fluorescent materials

Mohammadi, Mahnaz
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Dissertação
EN_US
Relevância na Pesquisa
57.8011%
Fluorescent effects have been observed for thousands of years. Stokes, in 1852, began the science of fluorescence culminating in his law of fluorescence, which explained that fluorescence emission occurs at longer wavelengths than the excitation wavelength. This phenomenon is observed extensively in the art world. Daylight fluorescent colors known as Day-Glo have become an artistic medium since the 1960s. Modern artists exploit these saturated and brilliant colors to glitter their painting. Multispectral imaging as a noninvasive technique has been used for archiving by museums and cultural-heritage institutions for about a decade. The complex fluorescence phenomenon has been often ignored in the multispectral projects. The ignored fluorescence results in errors in digital imaging of artwork containing fluorescent colors. The illuminant-dependency of the fluorescence radiance makes the fluorescence colorimetry and consequently spectral imaging more complex. In this dissertation an abridged imaging bi-spectrometer for artwork containing both fluorescent and non-fluorescent colors was developed. The method developed included two stages of reconstruction of the spectral reflected radiance factor and prediction of the fluorescent radiance factor. The estimation of the reflected radiance factor as a light source independent component was achieved by imaging with a series of short-wavelength cutoff filters placed in the illumination path. The fluorescent radiance factor...

Photoinhibitory printing on leaves, visualized by chlorophyll fluorescence imaging and confocal microscopy, is due to diminished fluorescence from grana

Osmond, C Barry; Schwartz, Owen; Gunning, Brian
Fonte: CSLI Publications Publicador: CSLI Publications
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
67.52436%
By analogy with the starch printing technique, it was hypothesised that photoinhibition could be used to print images on leaves that would be invisible to the eye, but easily revealed by chlorophyll fluorescence imaging. We first illustrate the process of chlorophyll fluorescence printing on leaves of the shade plant, Cissus rhombifolia, using photographs of artefacts from starch printing experiments in the laboratory of Molisch. We then use portraits of current leaders in chlorophyll fluorescence research to demonstrate the stability of these images in living tissues. Text printing from microfilm of Ewart's pioneering studies in photoinhibition shows the resolution of the method with the fixed-focus, portable, imaging system used here. The stability of images, as well as quenching analysis of images and of leaves, suggests that localised photoinactivation, rather than sustained photoprotection, is responsible for the detail displayed by fluorescence printing. Electron micrograph positives of stained thylakoids can be printed to create an illusion of what is imagined to be the source of chlorophyll fluorescence at the membrane level. Individual chloroplasts in adjacent cells under the grid pattern of granal stacks printed on leaves were also examined using a confocal microscope. Compared with chloroplasts in the shaded parts of the grid...

Definition and evaluation of the spatiotemporal variations in chlorophyll fluorescence during the phases of CAM and during endogenous rhythms in continuous light, in thick leaves of Kalanchoe daigremontiana

Maddess, Ted; Rascher, Uwe; Siebke, Katharina; Luttge, Ulrich; Osmond, Barry
Fonte: Georg Thieme Verlag Publicador: Georg Thieme Verlag
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
57.248813%
We used chlorophyll fluorescence imaging to examine the homogeneity of photosynthetic metabolism during CAM in the thick leaves of Kalanchoë daigrernontiana Hamet et Perrier de la Bâthie. Intense, persistent fluorescence from a DCMU treated thin leaf of