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Chemical Society Reviews Jul 2015Hydrogen sulfide (H2S), a gaseous species produced by both bacteria and higher eukaryotic organisms, including mammalian vertebrates, has attracted attention in recent... (Review)
Review
Hydrogen sulfide (H2S), a gaseous species produced by both bacteria and higher eukaryotic organisms, including mammalian vertebrates, has attracted attention in recent years for its contributions to human health and disease. H2S has been proposed as a cytoprotectant and gasotransmitter in many tissue types, including mediating vascular tone in blood vessels as well as neuromodulation in the brain. The molecular mechanisms dictating how H2S affects cellular signaling and other physiological events remain insufficiently understood. Furthermore, the involvement of H2S in metal-binding interactions and formation of related RSS such as sulfane sulfur may contribute to other distinct signaling pathways. Owing to its widespread biological roles and unique chemical properties, H2S is an appealing target for chemical biology approaches to elucidate its production, trafficking, and downstream function. In this context, reaction-based fluorescent probes offer a versatile set of screening tools to visualize H2S pools in living systems. Three main strategies used in molecular probe development for H2S detection include azide and nitro group reduction, nucleophilic attack, and CuS precipitation. Each of these approaches exploits the strong nucleophilicity and reducing potency of H2S to achieve selectivity over other biothiols. In addition, a variety of methods have been developed for the detection of other reactive sulfur species (RSS), including sulfite and bisulfite, as well as sulfane sulfur species and related modifications such as S-nitrosothiols. Access to this growing chemical toolbox of new molecular probes for H2S and related RSS sets the stage for applying these developing technologies to probe reactive sulfur biology in living systems.
Topics: Fluorescent Dyes; Humans; Hydrogen Sulfide; Molecular Imaging
PubMed: 25474627
DOI: 10.1039/c4cs00298a -
Molecular Imaging 2017Hydrolytic enzymes are a large class of biological catalysts that play a vital role in a plethora of critical biochemical processes required to maintain human health.... (Review)
Review
Hydrolytic enzymes are a large class of biological catalysts that play a vital role in a plethora of critical biochemical processes required to maintain human health. However, the expression and/or activity of these important enzymes can change in many different diseases and therefore represent exciting targets for the development of positron emission tomography (PET) and single-photon emission computed tomography (SPECT) radiotracers. This review focuses on recently reported radiolabeled substrates, reversible inhibitors, and irreversible inhibitors investigated as PET and SPECT tracers for imaging hydrolytic enzymes. By learning from the most successful examples of tracer development for hydrolytic enzymes, it appears that an early focus on careful enzyme kinetics and cell-based studies are key factors for identifying potentially useful new molecular imaging agents.
Topics: Enzymes; Hydrolysis; Kinetics; Molecular Imaging; Positron-Emission Tomography; Tomography, Emission-Computed, Single-Photon
PubMed: 28927325
DOI: 10.1177/1536012117717852 -
Journal of Echocardiography Jun 2020Similar to what has already occurred in cancer medicine, the management of cardiovascular conditions will likely be improved by non-invasive molecular imaging... (Review)
Review
Similar to what has already occurred in cancer medicine, the management of cardiovascular conditions will likely be improved by non-invasive molecular imaging technologies that can provide earlier or more accurate diagnosis. These techniques are already having a positive impact in pre-clinical research by providing insight into pathophysiology or efficacy of new therapies. Contrast enhanced ultrasound (CEU) molecular imaging is a technique that relies on the ultrasound detection of targeted microbubble contrast agents to examine molecular or cellular events that occur at the blood pool-endothelial interface. CEU molecular imaging techniques have been developed that are able to provide unique information on atherosclerosis, ischemia reperfusion injury, angiogenesis, vascular inflammation, and thrombus formation. Accordingly, CEU has the potential to be used in a wide variety of circumstances to detect disease early or at the bedside, and to guide appropriate therapy based on vascular phenotype. This review will describe the physical basis for CEU molecular imaging, and the specific disease processes for the pre-clinical translational research experience.
Topics: Cardiovascular Diseases; Contrast Media; Humans; Microbubbles; Molecular Imaging; Ultrasonography
PubMed: 32056137
DOI: 10.1007/s12574-020-00463-z -
Journal of Nuclear Medicine Technology Jun 2020
Review
Topics: Humans; Molecular Imaging; Nuclear Medicine; Precision Medicine
PubMed: 32605963
DOI: No ID Found -
Molecular Imaging and Biology Jun 2019
Topics: History, 20th Century; History, 21st Century; Humans; Molecular Imaging; Optical Imaging; Oxidation-Reduction
PubMed: 31020510
DOI: 10.1007/s11307-019-01359-w -
Philosophical Transactions. Series A,... Nov 2017Pharmaceutical research and development requires a systematic interrogation of a candidate molecule through clinical studies. To ensure resources are spent on only the... (Review)
Review
Pharmaceutical research and development requires a systematic interrogation of a candidate molecule through clinical studies. To ensure resources are spent on only the most promising molecules, early clinical studies must understand fundamental attributes of the drug candidate, including exposure at the target site, target binding and pharmacological response in disease. Molecular imaging has the potential to quantitatively characterize these properties in small, efficient clinical studies. Specific benefits of molecular imaging in this setting (compared to blood and tissue sampling) include non-invasiveness and the ability to survey the whole body temporally. These methods have been adopted primarily for neuroscience drug development, catalysed by the inability to access the brain compartment by other means. If we believe molecular imaging is a technology platform able to underpin clinical drug development, why is it not adopted further to enable earlier decisions? This article considers current drug development needs, progress towards integration of molecular imaging into studies, current impediments and proposed models to broaden use and increase impact.This article is part of the themed issue 'Challenges for chemistry in molecular imaging'.
Topics: Drug Development; Humans; Molecular Imaging; Molecular Probe Techniques; Multimodal Imaging; Precision Medicine; Radiopharmaceuticals
PubMed: 29038381
DOI: 10.1098/rsta.2017.0112 -
Angewandte Chemie (International Ed. in... Aug 2020Emerging from the origins of supramolecular chemistry and the development of selective chemical receptors that rely on lock-and-key binding, activity-based sensing... (Review)
Review
Emerging from the origins of supramolecular chemistry and the development of selective chemical receptors that rely on lock-and-key binding, activity-based sensing (ABS)-which utilizes molecular reactivity rather than molecular recognition for analyte detection-has rapidly grown into a distinct field to investigate the production and regulation of chemical species that mediate biological signaling and stress pathways, particularly metal ions and small molecules. Chemical reactions exploit the diverse chemical reactivity of biological species to enable the development of selective and sensitive synthetic methods to decipher their contributions within complex living environments. The broad utility of this reaction-driven approach facilitates application to imaging platforms ranging from fluorescence, luminescence, photoacoustic, magnetic resonance, and positron emission tomography modalities. ABS methods are also being expanded to other fields, such as drug and materials discovery.
Topics: Metals; Molecular Imaging; Small Molecule Libraries
PubMed: 31605413
DOI: 10.1002/anie.201909690 -
The Quarterly Journal of Nuclear... Dec 2009Lanthanide complexes are more and more used in biomedical imaging as contrast agents (CA). The development of these paramagnetic complexes as CA for medical magnetic... (Review)
Review
Lanthanide complexes are more and more used in biomedical imaging as contrast agents (CA). The development of these paramagnetic complexes as CA for medical magnetic resonance imaging (MRI) and luminescent probes for optical imaging is very complementary. Gd complexes are well known as CA for MRI and Eu/Tb complexes are often used in microscopy or fluorescence imaging. Each imaging technique has its limitation: low sensitivity but high spatial resolution for MRI and limited penetration but high sensitivity for optical imaging. A bimodal agent can be used for these two methods and give more informations, they can be visualized simultaneously by light and MR imaging. Such compounds are based on the coordination chemistry of the lanthanide ions with an organic ligand to form a stable complex and on the properties of the lanthanide ions. Gd complexes with a chromophore allows also the luminescent detection. This review describes the properties of the lanthanide ions and of their complexes and gives some typical applications of the complexes. The luminescence properties show high quantum yield and long luminescence lifetimes. The relaxometric data of the Gd complexes are comparable or higher than commercial and clinically Gd-DTPA derivatives.
Topics: Contrast Media; Energy Transfer; Europium; Fluorescent Dyes; Gadolinium; Humans; Lanthanoid Series Elements; Ligands; Luminescence; Magnetic Resonance Imaging; Models, Chemical; Molecular Imaging; Optics and Photonics; Terbium; Xylenes
PubMed: 20016451
DOI: No ID Found -
Neuroscience Bulletin Apr 2018Advances in radionuclide tracers have allowed for more accurate imaging that reflects the actions of numerous neurotransmitters, energy metabolism utilization,... (Review)
Review
Advances in radionuclide tracers have allowed for more accurate imaging that reflects the actions of numerous neurotransmitters, energy metabolism utilization, inflammation, and pathological protein accumulation. All of these achievements in molecular brain imaging have broadened our understanding of brain function in Parkinson's disease (PD). The implementation of molecular imaging has supported more accurate PD diagnosis as well as assessment of therapeutic outcome and disease progression. Moreover, molecular imaging is well suited for the detection of preclinical or prodromal PD cases. Despite these advances, future frontiers of research in this area will focus on using multi-modalities combining positron emission tomography and magnetic resonance imaging along with causal modeling with complex algorithms.
Topics: Brain; Humans; Molecular Imaging; Neuroimaging; Parkinson Disease
PubMed: 29282614
DOI: 10.1007/s12264-017-0202-6 -
Future Oncology (London, England) Oct 2013White light endoscopy has proven to be a very powerful tool in oncology. There is still, however, a need for better endoscopic techniques to overcome the current... (Review)
Review
White light endoscopy has proven to be a very powerful tool in oncology. There is still, however, a need for better endoscopic techniques to overcome the current limitations of white light optics. New technologies that allow higher sensitivity, improved microanatomy and molecular characterization have been available for in vitro microscopy and are now being translated into in vivo endoscopy. Endoscopic molecular imaging is still in its infancy but holds the promise for enhancing sensitivity for early lesions, thus allowing earlier diagnosis and enabling early image-guided endoscopic intervention. A key feature of endoscopic molecular imaging is its increased sensitivity and specificity, which will be illustrated in this article, as well as describing perspectives on its future use in oncologic surgery.
Topics: Endoscopy; Humans; Molecular Imaging; Neoplasms
PubMed: 24106901
DOI: 10.2217/fon.13.123