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Janasik D, Jasiński K, Węglarz W, Nemec I, Jewula P, Krawczyk T. Ratiometric pH-Responsive 19F Magnetic Resonance Imaging Contrast Agents Based on Hydrazone Switches. Anal Chem 2022; 94:3427-3431. [PMID: 35156816 PMCID: PMC8892427 DOI: 10.1021/acs.analchem.1c04978] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 02/10/2022] [Indexed: 12/13/2022]
Abstract
Hydrazone-based molecular switches serve as efficient ratiometric pH-sensitive agents that can be tracked with 19F NMR/MRI and 1H NMR. Structural changes induced between pH 3 and 4 lead to signal appearance and disappearance at 1H and 19F NMR spectra allowing ratiometric pH measurements. The most pronounced are resonances of the CF3 group shifted by 1.8 ppm with 19F NMR and a hydrazone proton shifted by 2 ppm with 1H NMR.
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Affiliation(s)
- Dawid Janasik
- Department
of Chemical Organic Technology and Petrochemistry, Silesian University of Technology Krzywoustego 4,44-100 Gliwice, Poland
| | - Krzysztof Jasiński
- Institute
of Nuclear Physics Polish Academy of Sciences, 31-342 Krakow, Poland
| | | | - Ivan Nemec
- Central
European Institute of Technology Brno University of Technology, Purkyňova 123, 612-00 Brno, Czech
Republic
- Department
of Inorganic Chemistry, Faculty of Science, Palacký University 17. Listopadu 1192/12, 771 46 Olomouc, Czech Republic
| | - Pawel Jewula
- Central
European Institute of Technology Brno University of Technology, Purkyňova 123, 612-00 Brno, Czech
Republic
| | - Tomasz Krawczyk
- Department
of Chemical Organic Technology and Petrochemistry, Silesian University of Technology Krzywoustego 4,44-100 Gliwice, Poland
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Kim H, Krishnamurthy LC, Sun PZ. Brain pH Imaging and its Applications. Neuroscience 2021; 474:51-62. [PMID: 33493621 DOI: 10.1016/j.neuroscience.2021.01.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 01/12/2021] [Accepted: 01/13/2021] [Indexed: 12/14/2022]
Abstract
Acid-base homeostasis and pH regulation are critical for normal tissue metabolism and physiology, and brain tissue pH alters in many diseased states. Several noninvasive tissue pH Magnetic Resonance (MR) techniques have been developed over the past few decades to shed light on pH change during tissue function and dysfunction. Nevertheless, there are still challenges for mapping brain pH noninvasively at high spatiotemporal resolution. To address this unmet biomedical need, chemical exchange saturation transfer (CEST) MR techniques have been developed as a sensitive means for non-invasive pH mapping. This article briefly reviews the basic principles of different pH measurement techniques with a focus on CEST imaging of pH. Emerging pH imaging applications in the tumor are provided as examples throughout the narrative, and CEST pH imaging in acute stroke is discussed in the final section.
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Affiliation(s)
- Hahnsung Kim
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, United States; Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, United States
| | - Lisa C Krishnamurthy
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA, Decatur, GA, United States; Department of Physics & Astronomy, Georgia State University, Atlanta, GA, United States
| | - Phillip Zhe Sun
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, United States; Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, United States.
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Jirak D, Galisova A, Kolouchova K, Babuka D, Hruby M. Fluorine polymer probes for magnetic resonance imaging: quo vadis? MAGMA (NEW YORK, N.Y.) 2019; 32:173-185. [PMID: 30498886 PMCID: PMC6514090 DOI: 10.1007/s10334-018-0724-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 11/19/2018] [Accepted: 11/21/2018] [Indexed: 12/26/2022]
Abstract
Over the last few years, the development and relevance of 19F magnetic resonance imaging (MRI) for use in clinical practice has emerged. MRI using fluorinated probes enables the achievement of a specific signal with high contrast in MRI images. However, to ensure sufficient sensitivity of 19F MRI, fluorine probes with a high content of chemically equivalent fluorine atoms are required. The majority of 19F MRI agents are perfluorocarbon emulsions, which have a broad range of applications in molecular imaging, although the content of fluorine atoms in these molecules is limited. In this review, we focus mainly on polymer probes that allow higher fluorine content and represent versatile platforms with properties tailorable to a plethora of biomedical in vivo applications. We discuss the chemical development, up to the first imaging applications, of these promising fluorine probes, including injectable polymers that form depots that are intended for possible use in cancer therapy.
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Affiliation(s)
- Daniel Jirak
- Institute for Clinical and Experimental Medicine, Vídeňská 9, 140 21, Prague 4, Czech Republic.
- Institute of Biophysics and Informatics, 1st Medicine Faculty, Charles University, Salmovská 1, 120 00, Prague, Czech Republic.
- Faculty of Health Studies, Technical University of Liberec, Studentská 1402/2, 461 17, Liberec 1, Czech Republic.
| | - Andrea Galisova
- Institute for Clinical and Experimental Medicine, Vídeňská 9, 140 21, Prague 4, Czech Republic
| | - Kristyna Kolouchova
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského sq. 2, 162 06, Prague 6, Czech Republic
| | - David Babuka
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského sq. 2, 162 06, Prague 6, Czech Republic
| | - Martin Hruby
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského sq. 2, 162 06, Prague 6, Czech Republic
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Yu XC, Yang C, Ding J, Niu X, Hu Y, Jin C. Characterizations of the Interactions between Escherichia coli Periplasmic Chaperone HdeA and Its Native Substrates during Acid Stress. Biochemistry 2017; 56:5748-5757. [PMID: 29016106 DOI: 10.1021/acs.biochem.7b00724] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The bacterial acid-resistant chaperone HdeA is a "conditionally disordered" protein that functions at low pH when it undergoes a transition from a well-folded dimer to an unfolded monomer. The dimer dissociation and unfolding processes result in exposure of hydrophobic surfaces that allows binding to a broad range of client proteins. To fully elucidate the chaperone mechanism of HdeA, it is crucial to understand how the activated HdeA interacts with its native substrates during acid stress. Herein, we present a nuclear magnetic resonance study of the pH-dependent HdeA-substrate interactions. Our results show that the activation of HdeA is not only induced by acidification but also regulated by the presence of unfolded substrates. The variable extent of unfolding of substrates differentially regulates the HdeA-substrate interaction, and the binding further affects the HdeA conformation. Finally, we show that HdeA binds its substrates heterogeneously, and the "amphiphilic" model for HdeA-substrate interaction is discussed.
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Affiliation(s)
- Xing-Chi Yu
- College of Chemistry and Molecular Engineering, ‡Beijing Nuclear Magnetic Resonance Center, §College of Life Sciences, and ∥Beijing National Laboratory for Molecular Sciences, Peking University , Beijing 100871, China
| | - Chengfeng Yang
- College of Chemistry and Molecular Engineering, ‡Beijing Nuclear Magnetic Resonance Center, §College of Life Sciences, and ∥Beijing National Laboratory for Molecular Sciences, Peking University , Beijing 100871, China
| | - Jienv Ding
- College of Chemistry and Molecular Engineering, ‡Beijing Nuclear Magnetic Resonance Center, §College of Life Sciences, and ∥Beijing National Laboratory for Molecular Sciences, Peking University , Beijing 100871, China
| | - Xiaogang Niu
- College of Chemistry and Molecular Engineering, ‡Beijing Nuclear Magnetic Resonance Center, §College of Life Sciences, and ∥Beijing National Laboratory for Molecular Sciences, Peking University , Beijing 100871, China
| | - Yunfei Hu
- College of Chemistry and Molecular Engineering, ‡Beijing Nuclear Magnetic Resonance Center, §College of Life Sciences, and ∥Beijing National Laboratory for Molecular Sciences, Peking University , Beijing 100871, China
| | - Changwen Jin
- College of Chemistry and Molecular Engineering, ‡Beijing Nuclear Magnetic Resonance Center, §College of Life Sciences, and ∥Beijing National Laboratory for Molecular Sciences, Peking University , Beijing 100871, China
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Kim RY, Yau MC, Galpin JD, Seebohm G, Ahern CA, Pless SA, Kurata HT. Atomic basis for therapeutic activation of neuronal potassium channels. Nat Commun 2015; 6:8116. [PMID: 26333338 PMCID: PMC4561856 DOI: 10.1038/ncomms9116] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 07/21/2015] [Indexed: 12/25/2022] Open
Abstract
Retigabine is a recently approved anticonvulsant that acts by potentiating neuronal M-current generated by KCNQ2–5 channels, interacting with a conserved Trp residue in the channel pore domain. Using unnatural amino-acid mutagenesis, we subtly altered the properties of this Trp to reveal specific chemical interactions required for retigabine action. Introduction of a non-natural isosteric H-bond-deficient Trp analogue abolishes channel potentiation, indicating that retigabine effects rely strongly on formation of a H-bond with the conserved pore Trp. Supporting this model, substitution with fluorinated Trp analogues, with increased H-bonding propensity, strengthens retigabine potency. In addition, potency of numerous retigabine analogues correlates with the negative electrostatic surface potential of a carbonyl/carbamate oxygen atom present in most KCNQ activators. These findings functionally pinpoint an atomic-scale interaction essential for effects of retigabine and provide stringent constraints that may guide rational improvement of the emerging drug class of KCNQ channel activators. The antiepileptic drug retigabine potentiates neuronal KCNQ potassium channels. Here, the authors use a combination of unnatural amino acid mutagenesis and electrophysiology to show that retigabine acts by hydrogen bonding with a tryptophan indole nitrogen in the channel pore.
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Affiliation(s)
- Robin Y Kim
- Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, 2176 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3
| | - Michael C Yau
- Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, 2176 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3
| | - Jason D Galpin
- Department of Molecular Physiology and Biophysics, University of Iowa, 285 Newton Road, Iowa City, Iowa 52242, USA
| | - Guiscard Seebohm
- Department of Cardiovascular Medicine, University Hospital Münster, Albert-Schweitzer-Campus 1 (Gebäude D3), D-48149 Münster, Germany
| | - Christopher A Ahern
- Department of Molecular Physiology and Biophysics, University of Iowa, 285 Newton Road, Iowa City, Iowa 52242, USA
| | - Stephan A Pless
- Department of Drug Design and Pharmacology (Center for Biopharmaceuticals), University of Copenhagen, Jagtvej 160, DK-2100 Copenhagen, Denmark
| | - Harley T Kurata
- Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, 2176 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3
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Pless SA, Galpin JD, Niciforovic AP, Kurata HT, Ahern CA. Hydrogen bonds as molecular timers for slow inactivation in voltage-gated potassium channels. eLife 2013; 2:e01289. [PMID: 24327560 PMCID: PMC3852034 DOI: 10.7554/elife.01289] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Voltage-gated potassium (Kv) channels enable potassium efflux and membrane repolarization in excitable tissues. Many Kv channels undergo a progressive loss of ion conductance in the presence of a prolonged voltage stimulus, termed slow inactivation, but the atomic determinants that regulate the kinetics of this process remain obscure. Using a combination of synthetic amino acid analogs and concatenated channel subunits we establish two H-bonds near the extracellular surface of the channel that endow Kv channels with a mechanism to time the entry into slow inactivation: an intra-subunit H-bond between Asp447 and Trp434 and an inter-subunit H-bond connecting Tyr445 to Thr439. Breaking of either interaction triggers slow inactivation by means of a local disruption in the selectivity filter, while severing the Tyr445–Thr439 H-bond is likely to communicate this conformational change to the adjacent subunit(s). DOI:http://dx.doi.org/10.7554/eLife.01289.001 Proteins are made from long chains of smaller molecules, called amino acids. These chains twist and bend into complex three-dimensional shapes, and sometimes two or more chains, or ‘subunits’, are packed into a protein. These shapes are often held together by hydrogen bonds between some of the amino acids. Moreover, since the shape of a protein defines its function, some proteins must be able to switch between different shapes to function properly. Ion channels are proteins that form pores through cell membranes, allowing ions to flow in and out of the cell. Potassium ion channels, which are found in neurons and heart muscle cells, have four subunits that move to open or close the central pore in response to various signals. The closing of the channels can be ‘fast’ or ‘slow’. When the channels are closed quickly (called fast inactivation), a small part of the protein ‘plugs’ the pore from the inside of the cell. However, the mechanism behind slow inactivation remained obscure. It was thought to involve hydrogen bonds between some of the bulky amino acids that are found at the edge the pore. However, testing this hypothesis—by replacing these amino acids with alternatives that cannot form hydrogen bonds—was tricky because none of the 20 naturally occurring amino acids were alike enough to be suitable replacements. Now, Pless et al. have overcome this limitation by using synthetic amino acids that form hydrogen bonds that are stronger or weaker than those formed by the amino acids they are replacing. The results suggest that two types of hydrogen bond keep the pore open: one is a bond between two amino acids in the same subunit, and the other is an inter-subunit bond between amino acids in neighbouring subunits. Pless et al. suggest that opening the channel causes small movements that gradually weaken, and eventually break, these bonds in one of the four subunits. Specific amino acids within the pore are then free to twist and—via a cascade of similar movements in the other three subunits—block the pore and halt the flow of ions. As such, these networks of hydrogen bonds act as pre-set breaking points allowing channels to close, even in response to continued stimulation. Since regulated potassium channel activity underpins healthy neurons and heart muscles; understanding what controls their inactivation rate may lead to new approaches to tune their activity and treatments for important diseases. DOI:http://dx.doi.org/10.7554/eLife.01289.002
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Affiliation(s)
- Stephan A Pless
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, Canada
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Bartusik D, Tomanek B. Detection of (19)F-labeled biopharmaceuticals in cell cultures with magnetic resonance. Adv Drug Deliv Rev 2013; 65:1056-64. [PMID: 23603212 DOI: 10.1016/j.addr.2013.04.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 03/18/2013] [Accepted: 04/09/2013] [Indexed: 02/06/2023]
Abstract
Magnetic resonance (MR) studies of the therapeutic efficacy of fluorinated drugs have recently become possible due to improvements in detection including the application of very strong magnetic fields up to 9.4Tesla (T). These advances allow tracking, identification, and quantification of (19)F-labeled biopharmaceuticals using (19)F MR imaging ((19)F MRI) and spectroscopy ((19)F MRS). Both techniques are noninvasive, are nondestructive, and enable serial measurements. They also allow for controlled and systematic studies of cellular metabolism in cancerous tissue in vivo (small animals and humans) and in vitro (body fluids, cells culture, tissue extracts and isolated tissues). Here we provide an overview of the (19)F MRI and (19)F MRS techniques used for tracking (19)F labeled anticancer chemotherapeutics and antibodies which allow quantification of drug uptake in cancer cells in vitro.
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Yu JX, Hallac RR, Chiguru S, Mason RP. New frontiers and developing applications in 19F NMR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2013; 70:25-49. [PMID: 23540575 PMCID: PMC3613763 DOI: 10.1016/j.pnmrs.2012.10.001] [Citation(s) in RCA: 142] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 10/23/2012] [Indexed: 05/06/2023]
Affiliation(s)
- Jian-Xin Yu
- Laboratory of Prognostic Radiology, Division of Advanced Radiological Sciences, Department of Radiology, UT Southwestern Medical Center, Dallas, Texas
| | - Rami R. Hallac
- Laboratory of Prognostic Radiology, Division of Advanced Radiological Sciences, Department of Radiology, UT Southwestern Medical Center, Dallas, Texas
| | - Srinivas Chiguru
- Laboratory of Prognostic Radiology, Division of Advanced Radiological Sciences, Department of Radiology, UT Southwestern Medical Center, Dallas, Texas
| | - Ralph P. Mason
- Laboratory of Prognostic Radiology, Division of Advanced Radiological Sciences, Department of Radiology, UT Southwestern Medical Center, Dallas, Texas
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Ruiz-Cabello J, Barnett BP, Bottomley PA, Bulte JW. Fluorine (19F) MRS and MRI in biomedicine. NMR IN BIOMEDICINE 2011; 24:114-29. [PMID: 20842758 PMCID: PMC3051284 DOI: 10.1002/nbm.1570] [Citation(s) in RCA: 366] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Revised: 04/23/2010] [Accepted: 04/26/2010] [Indexed: 05/04/2023]
Abstract
Shortly after the introduction of (1)H MRI, fluorinated molecules were tested as MR-detectable tracers or contrast agents. Many fluorinated compounds, which are nontoxic and chemically inert, are now being used in a broad range of biomedical applications, including anesthetics, chemotherapeutic agents, and molecules with high oxygen solubility for respiration and blood substitution. These compounds can be monitored by fluorine ((19)F) MRI and/or MRS, providing a noninvasive means to interrogate associated functions in biological systems. As a result of the lack of endogenous fluorine in living organisms, (19)F MRI of 'hotspots' of targeted fluorinated contrast agents has recently opened up new research avenues in molecular and cellular imaging. This includes the specific targeting and imaging of cellular surface epitopes, as well as MRI cell tracking of endogenous macrophages, injected immune cells and stem cell transplants.
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Affiliation(s)
- Jesús Ruiz-Cabello
- Russell H. Morgan Department of Radiology, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Vascular Biology Program and Cellular Imaging Section, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, USA
- NMR Group, Institute of Functional Studies, Complutense University and CIBERES, Madrid, Spain
| | - Brad P. Barnett
- Russell H. Morgan Department of Radiology, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Vascular Biology Program and Cellular Imaging Section, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Paul A. Bottomley
- Russell H. Morgan Department of Radiology, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jeff W.M. Bulte
- Russell H. Morgan Department of Radiology, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Vascular Biology Program and Cellular Imaging Section, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, USA
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Panyi G, Deutsch C. Probing the cavity of the slow inactivated conformation of shaker potassium channels. ACTA ACUST UNITED AC 2007; 129:403-18. [PMID: 17438120 PMCID: PMC2154382 DOI: 10.1085/jgp.200709758] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Slow inactivation involves a local rearrangement of the outer mouth of voltage-gated potassium channels, but nothing is known regarding rearrangements in the cavity between the activation gate and the selectivity filter. We now report that the cavity undergoes a conformational change in the slow-inactivated state. This change is manifest as altered accessibility of residues facing the aqueous cavity and as a marked decrease in the affinity of tetraethylammonium for its internal binding site. These findings have implications for global alterations of the channel during slow inactivation and putative coupling between activation and slow-inactivation gates.
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Affiliation(s)
- Gyorgy Panyi
- Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, Hungary.
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Capancioni S, Schwach-Abdellaoui K, Kloeti W, Herrmann W, Brosig H, Borchert HH, Heller J, Gurny R. In Vitro Monitoring of Poly(ortho ester) Degradation by Electron Paramagnetic Resonance Imaging. Macromolecules 2003. [DOI: 10.1021/ma034365q] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sergio Capancioni
- School of Pharmacy, University of Geneva, Quai Ernest-Ansermet 30, 1211 Geneva 4, Switzerland; Department of Mass Spectrometry, University of Geneva, 1211 Geneva 4, Switzerland; Department of Pharmacy, Humboldt University of Berlin, 13086 Berlin, Germany; and A.P. Pharma, Redwood City, California 94063
| | - Khadija Schwach-Abdellaoui
- School of Pharmacy, University of Geneva, Quai Ernest-Ansermet 30, 1211 Geneva 4, Switzerland; Department of Mass Spectrometry, University of Geneva, 1211 Geneva 4, Switzerland; Department of Pharmacy, Humboldt University of Berlin, 13086 Berlin, Germany; and A.P. Pharma, Redwood City, California 94063
| | - Werner Kloeti
- School of Pharmacy, University of Geneva, Quai Ernest-Ansermet 30, 1211 Geneva 4, Switzerland; Department of Mass Spectrometry, University of Geneva, 1211 Geneva 4, Switzerland; Department of Pharmacy, Humboldt University of Berlin, 13086 Berlin, Germany; and A.P. Pharma, Redwood City, California 94063
| | - Werner Herrmann
- School of Pharmacy, University of Geneva, Quai Ernest-Ansermet 30, 1211 Geneva 4, Switzerland; Department of Mass Spectrometry, University of Geneva, 1211 Geneva 4, Switzerland; Department of Pharmacy, Humboldt University of Berlin, 13086 Berlin, Germany; and A.P. Pharma, Redwood City, California 94063
| | - Holger Brosig
- School of Pharmacy, University of Geneva, Quai Ernest-Ansermet 30, 1211 Geneva 4, Switzerland; Department of Mass Spectrometry, University of Geneva, 1211 Geneva 4, Switzerland; Department of Pharmacy, Humboldt University of Berlin, 13086 Berlin, Germany; and A.P. Pharma, Redwood City, California 94063
| | - Hans-Hubert Borchert
- School of Pharmacy, University of Geneva, Quai Ernest-Ansermet 30, 1211 Geneva 4, Switzerland; Department of Mass Spectrometry, University of Geneva, 1211 Geneva 4, Switzerland; Department of Pharmacy, Humboldt University of Berlin, 13086 Berlin, Germany; and A.P. Pharma, Redwood City, California 94063
| | - Jorge Heller
- School of Pharmacy, University of Geneva, Quai Ernest-Ansermet 30, 1211 Geneva 4, Switzerland; Department of Mass Spectrometry, University of Geneva, 1211 Geneva 4, Switzerland; Department of Pharmacy, Humboldt University of Berlin, 13086 Berlin, Germany; and A.P. Pharma, Redwood City, California 94063
| | - Robert Gurny
- School of Pharmacy, University of Geneva, Quai Ernest-Ansermet 30, 1211 Geneva 4, Switzerland; Department of Mass Spectrometry, University of Geneva, 1211 Geneva 4, Switzerland; Department of Pharmacy, Humboldt University of Berlin, 13086 Berlin, Germany; and A.P. Pharma, Redwood City, California 94063
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Kroll C, Hermann W, Stösser R, Borchert HH, Mäder K. Influence of drug treatment on the microacidity in rat and human skin--an in vitro electron spin resonance imaging study. Pharm Res 2001; 18:525-30. [PMID: 11451041 DOI: 10.1023/a:1011066613621] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE The possibilities of the noninvasive examination of microacidity (5) in different depths of the skin in vitro was explored, and the impact of drug treatment on the pH inside the skin was studied. METHODS Spectral-spatial electron spin resonance imaging (ss-ESRI) and pH-sensitive nitroxides were used to obtain a pH map of rat and human skin in vitro. RESULTS The dermal application of therapeutically used acids, such as salicylic acid and azelaic acid, caused a plain change of microacidity (pH) inside the skin. Species-linked differences between rat and human skin samples with respect to penetration and microacidity were found. CONCLUSIONS ESRI has been shown to be a new and completely noninvasive method to monitor microacidity in different skin layers and on the skin surface. This nondestructive method allows serial measurements on skin samples to be performed without any preparatory steps.
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Affiliation(s)
- C Kroll
- Department of Pharmacy, Humboldt University of Berlin, Germany
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13
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Metzler DE, Metzler CM, Sauke DJ. Determining Structures and Analyzing Cells. Biochemistry 2001. [DOI: 10.1016/b978-012492543-4/50006-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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14
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Pietri S, Miollan M, Martel S, Le Moigne F, Blaive B, Culcasi M. alpha - and beta -phosphorylated amines and pyrrolidines, a new class of low toxic highly sensitive 31P NMR pH indicators. Modeling of pKa and chemical shift values as a function of substituents. J Biol Chem 2000; 275:19505-12. [PMID: 10748044 DOI: 10.1074/jbc.m001784200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Fourteen linear and cyclic alpha- and beta-aminophosphonates in which the P-atom is substituted by alkoxy groups have been synthesized and evaluated as (31)P NMR pH markers in Krebs-Henseleit buffer. pK(a) values varied with substitution in the range 1.3-9.1, giving potentially access to a wide range of pH. Temperature had a weak influence on pH and a dramatic increase in ionic strength slightly modified the pK(a) of the pyrrolidine diethyl(2-methylpyrrolidin-2-yl)phosphonate (DEPMPH). All compounds displayed a 4-fold better NMR sensitivity than inorganic phosphate or other commonly used phosphonates, as assessed by differences delta(b)-delta(a) between the chemical shifts of the protonated and the unprotonated forms. In isolated perfused rat hearts, a non-toxic concentration window of 1.5-15 mm was determined for three representative compounds. Using empirical linear relationships, the experimental values of pK(a), delta(a), and delta(b) have been correlated with the two-dimensional structure, i.e. the chemical nature of substituents bonded to the secondary amine and P-atom. The data suggest that DEPMPH and its cyclic and linear variants are ideal versatile (31)P NMR probes for the study of tenuous pH changes in biological processes.
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Affiliation(s)
- S Pietri
- Structure et Réactivité des Espèces Paramagnétiques, CNRS-UMR 6517, France.
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15
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16
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Harper JL, Smith RA, Bedford JJ, Leader JP. Synthesis, acidity and 19F NMR characteristics of imidazoles bearing 1-fluorinated substituents with potential application as probes for intracellular pH determination. Tetrahedron 1997. [DOI: 10.1016/s0040-4020(97)00487-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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17
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Wright WW, Vanderkooi JM. Use of IR absorption of the carboxyl group of amino acids and their metabolites to determine pKs, to study proteins, and to monitor enzymatic activity. ACTA ACUST UNITED AC 1997. [DOI: 10.1002/(sici)1520-6343(1997)3:6<457::aid-bspy5>3.0.co;2-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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18
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Aoki Y, Akagi K, Tanaka Y, Kawai J, Takahashi M. Measurement of intratumor pH by pH indicator used in 19F-magnetic resonance spectroscopy. Measurement of extracellular pH decrease caused by hyperthermia combined with hydralazine. Invest Radiol 1996; 31:680-9. [PMID: 8915749 DOI: 10.1097/00004424-199611000-00002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
RATIONALE AND OBJECTIVES Without affect of metabolic changes, the authors measured intratumor pH by using 19F-magnetic resonance spectroscopy (MRS) with a fluorine compound (ZK-150471) on the basis of a calibration curve by pH electrode. METHODS Using the 4.7-tesla magnetic resonance apparatus, a fluorine compound that had acid-base equilibrial change and was impermeable within cell membranes was used. The fluorine compound was injected intravenously. The signal was obtained from mouse mammary cancer by creating an experimental tumor on the leg of mice. And the tumors, which were heated with and without hydralazine. The pH evaluated from chemical shift of the fluorine compound. The pH data was obtained from an electrode for reference. RESULTS The pH of nontreated tumors (n = 25) were 6.94 + 0.091. The pH decreased to 6.772 + 0.169 at 20 minutes even after 20 minutes of heating, and decreased to < 6.71 at 40 minutes after every heating time. The pH decreased to 6.456 at 20 minutes after 15 minutes of heating combined with hydralazine, and to 6.416 at 40 minutes after same treatment. CONCLUSIONS It is possible to measure the extracellular pH by 19F-MRS with the fluorine compound noninvasively in vivo, even after heating.
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Affiliation(s)
- Y Aoki
- Department of Radiology, Kansai Medical University, Osaka, Japan
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19
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Wasser JS, Lawler RG, Jackson DC. Nuclear Magnetic Resonance Spectroscopy and Its Applications in Comparative Physiology. ACTA ACUST UNITED AC 1996. [DOI: 10.1086/physzool.69.1.30164198] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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20
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Ruiz-Cabello J, Cohen JS. NMR and the study of pathological state in cells and tissues. INTERNATIONAL REVIEW OF CYTOLOGY 1993; 145:1-63. [PMID: 8500979 DOI: 10.1016/s0074-7696(08)60424-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- J Ruiz-Cabello
- Department of Pharmacology, Georgetown University Medical School, Washington, D.C. 20007
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21
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22
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23
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Prior MJW, Maxwell RJ, Griffiths JR. Fluorine-19F NMR Spectroscopy and Imaging In-Vivo. ACTA ACUST UNITED AC 1992. [DOI: 10.1007/978-3-642-77218-4_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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24
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Commodari F, Sanctuary BC, Feindel W, Shoubridge EA. Alkalosis monitored by 31P NMR in a human glioma cell line exposed to the anti-tumor drug 1,3-bis(2-chloroethyl)-1-nitrosourea. Magn Reson Med 1991; 22:394-403. [PMID: 1812375 DOI: 10.1002/mrm.1910220247] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A transient alkalosis of similar magnitude to that observed in vivo has been observed using 31P NMR and 2-deoxy-D-glucose-6-phosphate as a pH marker in a human glioma cell line, SKI-1, with demonstrated sensitivity to 1,3-bis(2-chloroethyl)-1-nitrosourea. At an effective dose of 5 +/- 1 x 10 micrograms/ml, an increase of 0.13 +/- 0.05 pH units was observed within 4 +/- 1 x 10 min of introducing the drug into the perfusion chamber. Although the in vitro response is of a time course much faster than that in vivo, these results suggest that this immediate pH change could be an indicator of the cytotoxic action of the drug.
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Affiliation(s)
- F Commodari
- Chemistry Department, McGill University, Montreal, Quebec, Canada
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25
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Lundberg P, Harmsen E, Ho C, Vogel HJ. Nuclear magnetic resonance studies of cellular metabolism. Anal Biochem 1990; 191:193-222. [PMID: 2085167 DOI: 10.1016/0003-2697(90)90210-z] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- P Lundberg
- Department of Biological Sciences, University of Calgary, Alberta, Canada
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26
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Kost GJ. pH standardization for phosphorus-31 magnetic resonance heart spectroscopy at different temperatures. Magn Reson Med 1990; 14:496-506. [PMID: 2355831 DOI: 10.1002/mrm.1910140307] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Intracellular pH typically is measured by NMR using the calibrated chemical shift of the inorganic phosphate peak in phosphorus-31 spectra. Heart spectroscopy experiments often require measurements of intracellular pH at temperatures from 5 to 37 degrees C. This paper provides NMR pH calibrations for this range of temperatures, a summary of calibration data reported to date, and a discussion of the factors influencing pH standardization.
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Affiliation(s)
- G J Kost
- Clinical Chemistry, School of Medicine, University of California, Davis 95616
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27
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Schnur G, Kimmich R, Lietzenmayer R. Hydrogen/fluorine retuning tomography. Applications to 1H image-guided volume-selective 19F spectroscopy and relaxometry of perfluorocarbon emulsions in tissue. Magn Reson Med 1990; 13:478-89. [PMID: 2325548 DOI: 10.1002/mrm.1910130315] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A hardware modification which permits the record of 19F images, spectra, and relaxation times with a 1H tomography bird-cager resonator is described. Changing the spectrometer frequency from 1H to 19F resonance and vice versa is possible without removing the object to be investigated. This hydrogen/fluorine retuning tomography (HYFY) technique permits studies of identical slices or volume elements with 1H as well as with 19F resonance. In particular, it is possible to localize volume elements on the basis of multislice proton images and then to investigate these volume elements with fluorine magnetic resonance by the aid of volume selection methods. For this purpose, pulse sequences for the localized and spectroscopically resolved determination of spin-lattice and transverse relaxation times have been developed. The applicability of the techniques has been demonstrated by the aid of phantom samples as well as with excised porcine organs which have been perfused with perfluorocarbon emulsions.
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Affiliation(s)
- G Schnur
- Sektion Kernresonanzspektroskopie, Universität Ulm, Federal Republic of Germany
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28
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Abstract
The pH dependence of the 19F chemical shift has been characterized for a number of fluorine-substituted aniline derivatives. These compounds constitute a new class of 19F nuclear magnetic resonance (NMR) pH indicators, characterized by single 19F resonance lines with sensitivities ranging from 2 to 7 ppm/pH unit near the aniline pKa; total shifts between conjugate acid and base of 5-15 ppm; and pKas ranging from 1 to 7. One compound, N,N-(methyl-2-carboxyisopropyl)-4-fluoroaniline, has a pKa of 6.8 and a sensitivity of 5 ppm/pH unit. This compound displays significant broadening of its 19F resonance near the aniline pKa (6.8), due to a decreased rate of exchange between conjugate acid and base species. Our results are consistent with slow dissociation of an intramolecular hydrogen bond in the zwitterionic species that limits the exchange rate between protonated and unprotonated forms for N,N-(methyl-2-carboxyisopropyl)-4-fluoroaniline.
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Affiliation(s)
- C J Deutsch
- Department of Physiology, University of Pennsylvania, Philadelphia 19104
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29
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London RE, Gabel SA. Determination of membrane potential and cell volume by 19F NMR using trifluoroacetate and trifluoroacetamide probes. Biochemistry 1989; 28:2378-82. [PMID: 2730869 DOI: 10.1021/bi00432a006] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The distribution of ionic species between intra- and extracellular compartments forms one basis for the determination of cell membrane potential. It is shown that fluorine-19 NMR studies of erythrocytes in the presence of trifluoroacetate, a stable, relatively nontoxic anion with pK = -0.3, provide a sensitive probe of membrane potential. Since such measurements are based on ion concentrations, the parallel use of the neutral analogue trifluoroacetamide to provide information on intra/extracellular volume ratios was also explored. In both cases, separate 19F resonances corresponding to intra- and extracellular ions were observed, with the intracellular resonance shifted downfield by approximately 0.2 ppm and the intracellular peak typically somewhat broader than the extracellular resonance. Studies with the band 3 anion-exchange inhibitor 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS) indicate that both transmembrane diffusion and flux involving the band 3 anion exchanger contribute to the observed transport of the trifluoroacetate anion. Intra/extracellular volume ratios determined on the basis of trifluoroacetamide intensity ratios were in good agreement with determinations based on measured hematocrits. On the basis of the high sensitivity of 19F NMR and the capability of monitoring volume changes simultaneously, the time resolution for these measurements can approach the lifetime of intracellular trifluoroacetate ions and hence be limited by the trifluoroacetate flux rate.
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Affiliation(s)
- R E London
- Laboratory of Molecular Biophysics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
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30
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Rottenberg H. Proton electrochemical potential gradient in vesicles, organelles, and prokaryotic cells. Methods Enzymol 1989; 172:63-84. [PMID: 2747544 DOI: 10.1016/s0076-6879(89)72008-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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