Other search tools

About this data

The publication data currently available has been vetted by Vanderbilt faculty, staff, administrators and trainees. The data itself is retrieved directly from NCBI's PubMed and is automatically updated on a weekly basis to ensure accuracy and completeness.

If you have any questions or comments, please contact us.

Results: 1 to 10 of 124

Publication Record

Connections

Rhodol-based thallium sensors for cellular imaging of potassium channel activity.
Dutter BF, Ender A, Sulikowski GA, Weaver CD
(2018) Org Biomol Chem 16: 5575-5579
MeSH Terms: Fluorescent Dyes, HEK293 Cells, Humans, Methylation, Microscopy, Confocal, Optical Imaging, Potassium Channels, Spectrometry, Fluorescence, Thallium, Xanthones
Show Abstract · Added April 10, 2019
Thallium (Tl+) flux assays enable imaging of potassium (K+) channel activity in cells and tissues by exploiting the permeability of K+ channels to Tl+ coupled with a fluorescent Tl+ sensitive dye. Common Tl+ sensing dyes utilize fluorescein as the fluorophore though fluorescein exhibits certain undesirable properties in these assays including short excitation wavelengths and pH sensitivity. To overcome these drawbacks, the replacement of fluorescein with rhodols was investigated. A library of 13 rhodol-based Tl+ sensors was synthesized and their properties and performance in Tl+ flux assays evaluated. The dimethyl rhodol Tl+ sensor emerged as the best of the series and performed comparably to fluorescein-based sensors while demonstrating greater pH tolerance in the physiological range and excitation and emission spectra 30 nm red-shifted from fluorescein.
0 Communities
1 Members
0 Resources
MeSH Terms
Selective Activation of N,N'-Diacyl Rhodamine Pro-fluorophores Paired with Releasing Enzyme, Porcine Liver Esterase (PLE).
Abney KK, Ramos-Hunter SJ, Romaine IM, Goodwin JS, Sulikowski GA, Weaver CD
(2018) Chemistry 24: 8985-8988
MeSH Terms: Animals, Esterases, HEK293 Cells, Humans, Liver, Microscopy, Confocal, Rhodamines, Spectrometry, Fluorescence, Swine
Show Abstract · Added April 10, 2019
This study reports the synthesis and testing of a family of rhodamine pro-fluorophores and an enzyme capable of converting pro-fluorophores to Rhodamine 110. We prepared a library of simple N,N'-diacyl rhodamines and investigated porcine liver esterase (PLE) as an enzyme to activate rhodamine-based pro-fluorophores. A PLE-expressing cell line generated an increase in fluorescence rapidly upon pro-fluorophore addition demonstrating the rhodamine pro-fluorophores are readily taken up and fluorescent upon PLE-mediated release. Rhodamine pro-fluorophore amides trifluoroacetamide (TFAm) and proponamide (PAm) appeared to be the best substrates using a cell-based assay using PLE expressing HEK293. Our pro-fluorophore series showed diffusion into live cells and resisted endogenous hydrolysis. The use of our engineered cell line containing the exogenous enzyme PLE demonstrated the rigorousness of amide masking when compared to cells not containing PLE. This simple and selective pro-fluorophore rhodamine pair with PLE offers the potential to be used in vitro and in vivo fluorescence based assays.
© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
0 Communities
1 Members
0 Resources
MeSH Terms
7,8-benzoflavone binding to human cytochrome P450 3A4 reveals complex fluorescence quenching, suggesting binding at multiple protein sites.
Marsch GA, Carlson BT, Guengerich FP
(2018) J Biomol Struct Dyn 36: 841-860
MeSH Terms: Benzoflavones, Binding Sites, Cytochrome P-450 CYP3A, Fluorescence, Humans, Kinetics, Ligands, Models, Chemical, Oxidation-Reduction, Protein Binding, Spectrometry, Fluorescence, Substrate Specificity
Show Abstract · Added March 14, 2018
Human cytochrome P450 (P450) 3A4 is involved in the metabolism of one-half of marketed drugs and shows cooperative interactions with some substrates and other ligands. The interaction between P450 3A4 and the known allosteric effector 7,8-benzoflavone (α-naphthoflavone, αNF) was characterized using steady-state fluorescence spectroscopy. The binding interaction of P450 3A4 and αNF effectively quenched the fluorescence of both the enzyme and ligand. The Hill Equation and Stern-Volmer fluorescence quenching models were used to evaluate binding of ligand to enzyme. P450 3A4 fluorescence was quenched by titration with αNF; at the relatively higher [αNF]/[P450 3A4] ratios in this experiment, two weaker quenching interactions were revealed (K 1.8-2.5 and 6.5 μM). A range is given for the stronger interaction since αNF quenching of P450 3A4 fluorescence changed the protein spectral profile: quenching of 315 nm emission was slightly more efficient (K 1.8 μM) than the quenching of protein fluorescence at 335 and 355 nm (K 2.5 and 2.1 μM, respectively). In the reverse titration, αNF fluorescence was quenched by P450 3A4; at the lower [αNF]/[P450 3A4] ratios here, two strong quenching interactions were revealed (K 0.048 and 1.0 μM). Thus, four binding interactions of αNF to P450 3A4 are suggested by this study, one of which may be newly recognized and which could affect studies of drug oxidations by this important enzyme.
0 Communities
1 Members
0 Resources
12 MeSH Terms
Quantitative assessment of fluorescent proteins.
Cranfill PJ, Sell BR, Baird MA, Allen JR, Lavagnino Z, de Gruiter HM, Kremers GJ, Davidson MW, Ustione A, Piston DW
(2016) Nat Methods 13: 557-62
MeSH Terms: Fluorescence, HeLa Cells, Humans, Luminescent Proteins, Microscopy, Fluorescence, Recombinant Fusion Proteins, Spectrometry, Fluorescence
Show Abstract · Added May 5, 2017
The advent of fluorescent proteins (FPs) for genetic labeling of molecules and cells has revolutionized fluorescence microscopy. Genetic manipulations have created a vast array of bright and stable FPs spanning blue to red spectral regions. Common to autofluorescent FPs is their tight β-barrel structure, which provides the rigidity and chemical environment needed for effectual fluorescence. Despite the common structure, each FP has unique properties. Thus, there is no single 'best' FP for every circumstance, and each FP has advantages and disadvantages. To guide decisions about which FP is right for a given application, we have quantitatively characterized the brightness, photostability, pH stability and monomeric properties of more than 40 FPs to enable straightforward and direct comparison between them. We focus on popular and/or top-performing FPs in each spectral region.
0 Communities
1 Members
0 Resources
7 MeSH Terms
1064  nm dispersive Raman spectroscopy of tissues with strong near-infrared autofluorescence.
Patil CA, Pence IJ, Lieber CA, Mahadevan-Jansen A
(2014) Opt Lett 39: 303-6
MeSH Terms: Breast, Feasibility Studies, Humans, Infrared Rays, Kidney, Liver, Spectrometry, Fluorescence, Spectrum Analysis, Raman
Show Abstract · Added March 31, 2014
Raman spectroscopy is an established technique for molecularly specific characterization of tissues. However, even with near-infrared (NIR) excitation, some tissues possess background autofluorescence, which can overwhelm Raman scattering. Here, we report collection of spectra from tissues with strong autofluorescence using a 1064 nm system with a high-throughput dispersive spectrometer and deep-cooled InGaAs array. Spectra collected at 1064 nm were compared with those collected at 785 nm in specimens from human breast, liver, and kidney. The results demonstrate superior performance at 1064 nm in the liver and kidney, where NIR autofluorescence is intense. The results indicate the feasibility of new biomedical applications for Raman spectroscopy at 1064 nm in tissues with strong autofluorescence.
0 Communities
1 Members
0 Resources
8 MeSH Terms
Quadruplex priming amplification for the detection of mRNA from surrogate patient samples.
Adams NM, Wang KK, Caprioli AC, Thomas LC, Kankia B, Haselton FR, Wright DW
(2014) Analyst 139: 1644-52
MeSH Terms: Base Sequence, Biosensing Techniques, Circular Dichroism, DNA Primers, Equipment Design, G-Quadruplexes, Humans, Magnets, Molecular Sequence Data, Nucleic Acid Amplification Techniques, RNA, Messenger, Spectrometry, Fluorescence, Xanthopterin
Show Abstract · Added May 27, 2014
Simple and rapid methods for detecting mRNA biomarkers from patient samples are valuable in settings with limited access to laboratory resources. In this report, we describe the development and evaluation of a self-contained assay to extract and quantify mRNA biomarkers from complex samples using a novel nucleic acid-based molecular sensor called quadruplex priming amplification (QPA). QPA is a simple and robust isothermal nucleic acid amplification method that exploits the stability of the G-quadruplex nucleotide structure to drive spontaneous strand melting from a specific DNA template sequence. Quantification of mRNA was enabled by integrating QPA with a magnetic bead-based extraction method using an mRNA-QPA interface reagent. The assay was found to maintain >90% of the maximum signal over a 4 °C range of operational temperatures (64-68 °C). QPA had a dynamic range spanning four orders of magnitude, with a limit of detection of ~20 pM template molecules using a highly controlled heating and optical system and a limit of detection of ~250 pM using a less optimal water bath and plate reader. These results demonstrate that this integrated approach has potential as a simple and effective mRNA biomarker extraction and detection assay for use in limited resource settings.
0 Communities
1 Members
0 Resources
13 MeSH Terms
A novel optical approach to intraoperative detection of parathyroid glands.
McWade MA, Paras C, White LM, Phay JE, Mahadevan-Jansen A, Broome JT
(2013) Surgery 154: 1371-7; discussion 1377
MeSH Terms: Humans, Intraoperative Period, Optical Devices, Optical Phenomena, Parathyroid Diseases, Parathyroid Glands, Parathyroidectomy, Spectrometry, Fluorescence, Spectroscopy, Near-Infrared, Thyroid Diseases, Thyroidectomy
Show Abstract · Added March 31, 2014
BACKGROUND - Inadvertent removal of parathyroid glands is a challenge in endocrine operations. There is a critical need for a diagnostic tool that provides sensitive, real-time parathyroid detection during procedures. We have developed an intraoperative technique using near-infrared (NIR) fluorescence for in vivo, real-time detection of the parathyroid regardless of its pathologic state.
METHODS - NIR fluorescence was measured intraoperatively from 45 patients undergoing parathyroidectomy and thyroidectomy. Spectra were measured from the parathyroid and surrounding neck tissues during the operation with the use of a portable, probe-based fluorescence system at 785-nm excitation. Accuracy was evaluated by comparison with histology or visual recognition by the surgeon.
RESULTS - NIR fluorescence detected the parathyroid in 100% of patients. Parathyroid fluorescence was stronger (1.2-18 times) than that of the thyroid with peak fluorescence at 822 nm. Surrounding tissues showed no auto-fluorescence. Disease state did not affect the ability to discriminate parathyroid glands but may account for signal variability.
CONCLUSION - NIR fluorescence spectroscopy can detect intraoperatively the parathyroid regardless of tissue pathology. The signal may be caused by calcium-sensing receptors present in the parathyroid. The signal strength and consistency indicates the simplicity and effectiveness of this method. Its implementation may limit operative time, decrease costs, and improve operative success rates.
Copyright © 2013 Mosby, Inc. All rights reserved.
0 Communities
1 Members
0 Resources
11 MeSH Terms
High-throughput fluorescence assay of cytochrome P450 3A4.
Cheng Q, Guengerich FP
(2013) Methods Mol Biol 987: 157-62
MeSH Terms: Coumarins, Cytochrome P-450 CYP3A, Cytochrome P-450 CYP3A Inhibitors, Enzyme Assays, Humans, Inhibitory Concentration 50, Ketoconazole, Spectrometry, Fluorescence
Show Abstract · Added March 26, 2014
Microtiter plate-based fluorescence assays allow rapid measurement of the catalytic activities of cytochrome P450 oxygenases (P450s). We describe a high-throughput fluorescence assay of P450 3A4, one of the key enzymes involved in xenobiotic metabolism. The assay involves the oxidative debenzylation of 7-hydroxy-4-trifluoromethyl coumarin, producing an increase in fluorescence.
0 Communities
1 Members
0 Resources
8 MeSH Terms
Rapid and specific measurements of superoxide using fluorescence spectroscopy.
Nazarewicz RR, Bikineyeva A, Dikalov SI
(2013) J Biomol Screen 18: 498-503
MeSH Terms: Cells, Cultured, Endothelial Cells, Ethidium, Humans, Spectrometry, Fluorescence, Superoxides, Xanthine Oxidase
Show Abstract · Added March 30, 2014
Superoxide plays a key role in many pathological processes; however, detection of superoxide by one of the most common methods using dihydroethidium (DHE) may be unspecific because of overlapping fluorescence of the superoxide-specific product, 2-OH-ethidium (2OH-E), and the unspecific oxidation product, ethidium. Here, we show a new optimized fluorescence spectroscopy protocol that allows rapid and specific detection of superoxide in cell-free systems and intact cells using DHE. We defined new optimized fluorescent settings to measure the superoxide-specific product and minimize the interference of unspecific DHE oxidation products. Using this protocol, we studied real-time superoxide production by xanthine oxidase- and menadione-treated cultured cells. Specificity of the plate reader-based superoxide measurements was confirmed by the inhibition of fluorescence with superoxide dismutase and high-performance liquid chromatography (HPLC) analysis. We show that limitations of the HPLC-based analysis can be overcome by the optimized fluorescence spectroscopy.
0 Communities
3 Members
0 Resources
7 MeSH Terms
The effect of temperature on the autofluorescence of scattering and non-scattering tissue.
Walsh AJ, Masters DB, Jansen ED, Welch AJ, Mahadevan-Jansen A
(2012) Lasers Surg Med 44: 712-8
MeSH Terms: Animals, Area Under Curve, Cornea, Fiber Optic Technology, Fluorescence, Lasers, Gas, Rats, Scattering, Radiation, Skin, Spectrometry, Fluorescence, Spectrum Analysis, Swine, Temperature
Show Abstract · Added March 7, 2014
BACKGROUND AND OBJECTIVES - With the increasing use of fluorescence in medical applications, a comprehensive understanding of the effect of temperature on tissue autofluorescence is essential. The purpose of this study is to explore the effect of temperature on the fluorescence of porcine cornea and rat skin and determine the relative contributions of irreversible changes in optical properties and in fluorescence yield.
STUDY DESIGN/MATERIALS AND METHODS - Fluorescence, diffuse reflectance, and temperature measurements were acquired from excised porcine cornea and rat skin over a temperature range of 0-80 °C. A dual excitation system was used with a 337 nm pulsed nitrogen laser for the fluorescence and a white light source for the diffuse reflectance measurements. A thermal camera measured tissue temperature. Optical property changes were inferred from diffuse reflectance measurements. The reversibility of the change in fluorescence was examined by acquiring measurements while the tissue sample cooled from the highest induced temperature to room temperature.
RESULTS - The fluorescence intensity decreased with increasing tissue temperature. This fluorescence change was reversible when the tissue was heated to a temperature of 45 °C, but irreversible when heated to a temperature of 80 °C.
CONCLUSION - Auto-fluorescence intensity dependence on temperature appears to be a combination of temperature-induced optical property changes and reduced fluorescence quantum yield due to changes in collagen structure. Temperature-induced changes in measured fluorescence must be taken into consideration in applications where fluorescence is used to diagnose disease or guide therapy.
Copyright © 2012 Wiley Periodicals, Inc.
0 Communities
1 Members
0 Resources
13 MeSH Terms