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https://www.readbyqxmd.com/read/29341012/biomedical-19f-mri-using-perfluorocarbons
#1
Tuba Güden-Silber, Sebastian Temme, Christoph Jacoby, Ulrich Flögel
Background-free fluorine (19F) MR imaging exhibits an excellent degree of specificity, and facilitates among others the in vivo visualization of inflammatory processes. Merging19F MR images with morphologically matching1H MR images enables the exact anatomic localization of the observed19F signal. Biochemically inert nanoemulsions of perfluorocarbons, which are known to be taken up by the macrophage/monocyte system, are widely used as contrast agents for preclinical applications. Herein, the most common protocols are described to obtain high-resolution and artifact-free19F MR images even for compounds with complex19F MR spectra...
2018: Methods in Molecular Biology
https://www.readbyqxmd.com/read/29340411/multiplexed-detection-of-nucleic-acids-using-19f-nmr-chemical-shift-changes-based-on-dna-photo-cross-linking-of-3-vinylcarbazole-derivatives
#2
Shigetaka Nakamura, Yasuharu Takashima, Kenzo Fujimoto
The detection methodology for nucleic acids is a useful tool for the analysis of biological systems and diagnosis of diseases. We demonstrated the feasibility of the detection of any nucleic acids based on large chemical shifts via ultrafast DNA photo-cross-linking and the effects of substitution by 3-vinylcarbazole derivatives. These chemical shifts enable the sequence-specific detection of any strand using hybridization chain reaction.
January 17, 2018: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/29330541/19f-perfluorocarbon-labeled-human-peripheral-blood-mononuclear-cells-can-be-detected-in-vivo-using-clinical-mri-parameters-in-a-therapeutic-cell-setting
#3
Corby Fink, Jeffrey M Gaudet, Matthew S Fox, Shashank Bhatt, Sowmya Viswanathan, Michael Smith, Joseph Chin, Paula J Foster, Gregory A Dekaban
A 19Fluorine (19F) perfluorocarbon cell labeling agent, when employed with an appropriate cellular MRI protocol, allows for in vivo cell tracking. 19F cellular MRI can be used to non-invasively assess the location and persistence of cell-based cancer vaccines and other cell-based therapies. This study was designed to determine the feasibility of labeling and tracking peripheral blood mononuclear cells (PBMC), a heterogeneous cell population. Under GMP-compliant conditions human PBMC were labeled with a 19F-based MRI cell-labeling agent in a manner safe for autologous re-injection...
January 12, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29330069/conformation-and-trimer-association-of-the-transmembrane-domain-of-the-parainfluenza-virus-fusion-protein-in-lipid-bilayers-from-solid-state-nmr-insights-into-the-sequence-determinants-of-trimer-structure-and-fusion-activity
#4
Myungwoon Lee, Hongwei Yao, Byungsu Kwon, Alan J Waring, Peter Ruchala, Chandan Singh, Mei Hong
Enveloped viruses enter cells by using their fusion proteins to merge the virus lipid envelope and the cell membrane. While crystal structures of the water-soluble ectodomains of many viral fusion proteins have been determined, the structure and assembly of the C-terminal transmembrane domain (TMD) remains poorly understood. Here we use solid-state NMR to determine the backbone conformation and oligomeric structure of the TMD of the parainfluenza virus 5 (PIV5) fusion protein. 13C chemical shifts indicate that the central leucine-rich segment of the TMD is α-helical in POPC/cholesterol membranes and POPE membranes, while the Ile- and Val-rich termini shift to the β-strand conformation in the POPE membrane...
January 9, 2018: Journal of Molecular Biology
https://www.readbyqxmd.com/read/29329228/current-nmr-techniques-for-structure-based-drug-discovery
#5
REVIEW
Toshihiko Sugiki, Kyoko Furuita, Toshimichi Fujiwara, Chojiro Kojima
A variety of nuclear magnetic resonance (NMR) applications have been developed for structure-based drug discovery (SBDD). NMR provides many advantages over other methods, such as the ability to directly observe chemical compounds and target biomolecules, and to be used for ligand-based and protein-based approaches. NMR can also provide important information about the interactions in a protein-ligand complex, such as structure, dynamics, and affinity, even when the interaction is too weak to be detected by ELISA or fluorescence resonance energy transfer (FRET)-based high-throughput screening (HTS) or to be crystalized...
January 12, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29327914/mechanistic-evaluation-of-bioorthogonal-decaging-with-trans-cyclooctene-the-effect-of-fluorine-substituents-on-aryl-azide-reactivity-and-decaging-from-the-1-2-3-triazoline
#6
Siddharth Sai Matikonda, Jessica M Fairhall, Franziska Fiedler, Suchaya Sanhajariya, Robert A J Tucker, Sarah Hook, Anna L Garden, Allan B Gamble
Bioorthogonal prodrug activation/decaging strategies need to be selective, rapid and release the drug from the masking group upon activation. The rates of the 1,3-dipolar cycloaddition between a trans-cyclooctene (TCO) and a series of fluorine-substituted azido-PABC self-immolative spacers caging two model drugs, and subsequent release from the 1,2,3-triazoline are reported. As the number of fluorine substituents on the PABC linker increases from one to four, the rate of cycloaddition increases by almost one-order of magnitude...
January 12, 2018: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/29324754/fast-quantitative-murine-cardiac-19f-mri-mrs-of-pfce-labeled-progenitor-stem-cells-and-macrophages-at-9-4t
#7
Christakis Constantinides, Mahon Maguire, Eileen McNeill, Ricardo Carnicer, Edyta Swider, Mangala Srinivas, Carolyn A Carr, Jurgen E Schneider
PURPOSE: To a) achieve cardiac 19F-Magnetic Resonance Imaging (MRI) of perfluoro-crown-ether (PFCE) labeled cardiac progenitor stem cells (CPCs) and bone-derived bone marrow macrophages, b) determine label concentration and cellular load limits, and c) achieve spectroscopic and image-based quantification. METHODS: Theoretical simulations and experimental comparisons of spoiled-gradient echo (SPGR), rapid acquisition with relaxation enhancement (RARE), and steady state at free precession (SSFP) pulse sequences, and phantom validations, were conducted using 19F MRI/Magnetic Resonance Spectroscopy (MRS) at 9...
2018: PloS One
https://www.readbyqxmd.com/read/29318102/extending-the-scope-of-19f-hyperpolarization-through-signal-amplification-by-reversible-exchange-in-mri-and-nmr-spectroscopy
#8
Alexandra M Olaru, Thomas B R Robertson, Jennifer S Lewis, Alex Antony, Wissam Iali, Ryan E Mewis, Simon B Duckett
Fluorinated ligands have a variety of uses in chemistry and industry, but it is their medical applications as 18F-labelled positron emission tomography (PET) tracers where they are most visible. In this work, we illustrate the potential of using 19F-containing ligands as future magnetic resonance imaging (MRI) contrast agents and as probes in magnetic resonance spectroscopy studies by significantly increasing their magnetic resonance detectability through the signal amplification by reversible exchange (SABRE) hyperpolarization method...
January 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29316122/spectroscopic-characterization-of-a-c-f-c-fluoronium-ion-in-solution
#9
Cody Ross Pitts, Maxwell Gargiulo Holl, Thomas Lectka
We report the first spectroscopic evidence for a [C-F-C]+ fluoronium ion in solution. Extensive NMR studies (19F, 1H, 13C) characterize a symmetrical cage-like species in which fluorine exhibits substantial covalent bonding to each of the two carbon atoms involved in the three-center interaction. Experimental NMR data comport well with calculated values to lend credence to the structural assignment. As the culminating experiment, the Saunders isotopic perturbation test definitively confirms a symmetrical structure...
January 9, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29307189/monitoring-thiol-ligand-exchange-on-au-nanoparticle-surfaces
#10
Martin Klünker, Mihail Mondeshki, Muhammad Nawaz Tahir, Wolfgang Tremel
Surface functionalization of nanoparticles (NPs) plays a crucial role for particle solubility and reactivity. It is vital for particle nucleation and growth as well as for catalysis. This raises the quest for functionalization efficiency and new approaches to probe the degree of surface coverage. We present an (in situ) 1H NMR study on the ligand exchange of oleylamine (OAm) by 1-octadecanethiol (ODT) as a function of particle size and repeated functionalization on Au NPs. Ligand exchange is an equilibrium reaction associated with a Nernst distribution, which often leads to incomplete surface functionalization following "standard" literature protocols...
January 8, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29305958/description-of-a-novel-mutation-in-the-atpc-gene-in-optochin-resistant-streptococcus-pneumoniae-strains-isolates-from-tunisia
#11
Anis Raddaoui, Farah Ben Tanfous, Wafa Achour, Rekaya Baaboura, Assia Benhassen
The identification of Streptocooccus pneumoniae among other α-hemolytic streptococci is based on phenotypic or genotypic characteristics as colony morphology, bile solubility and optochin susceptibility. We report in this study three optochin-resistant S. pneumoniae isolated from immunocompromised patients in Tunisia. The three isolates were positive for bile solubility test. The biochemical identification with API® 20 Strep was not discriminatory for two strains. The three strains had different serotypes (6C, 19F and 23F) and three different sequence types (ST386, ST320, and ST326)...
January 3, 2018: International Journal of Antimicrobial Agents
https://www.readbyqxmd.com/read/29301396/selective-radical-trifluoromethylation-of-native-residues-in-proteins
#12
Mateusz Imiołek, Gogulan Karunanithy, Wai-Lung Ng, Andrew J Baldwin, Veronique Emilie Gouverneur, Benjamin G Davis
The incorporation of fluorine can not only significantly facilitate the study of proteins but also potentially modulate their function. Whilst some biosynthetic methods allow global residue-replacement methods, post-translational fluorination would constitute a fast and efficient alternative. Here, we reveal a mild method for direct protein radical trifluoromethylation at native residues as a strategy for symmetric-multi-fluorine incorporation on mg scales with high recoveries. High selectivity towards tryptophan residues enhanced the utility of this direct trifluoromethylation technique allowing ready study of fluorinated protein constructs using 19F-NMR...
January 5, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29290827/local-intratracheal-delivery-of-perfluorocarbon-nanoparticles-to-lung-cancer-demonstrated-with-magnetic-resonance-multimodal-imaging
#13
Lina Wu, Xiaofei Wen, Xiance Wang, Chunan Wang, Xilin Sun, Kai Wang, Huiying Zhang, Todd Williams, Allen J Stacy, Junjie Chen, Anne H Schmieder, Gregory M Lanza, Baozhong Shen
Eighty percent of lung cancers originate as subtle premalignant changes in the airway mucosal epithelial layer of bronchi and alveoli, which evolve and penetrate deeper into the parenchyma. Liquid-ventilation, with perfluorocarbons (PFC) was first demonstrated in rodents in 1966 then subsequently applied as lipid-encapsulated PFC emulsions to improve pulmonary function in neonatal infants suffering with respiratory distress syndrome in 1996. Subsequently, PFC nanoparticles (NP) were extensively studied as intravenous (IV) vascular-constrained nanotechnologies for diagnostic imaging and targeted drug delivery applications...
2018: Theranostics
https://www.readbyqxmd.com/read/29289385/phenotypic-and-molecular-characterization-of-streptococcus-pneumoniae-in-pre-conjugate-vaccine-era-a-chinese-hospital-based-retrospective-study
#14
Ling Li, Jinjian Fu, Shunming Li, Dan Guo, Zhiyao Chen, Sidong Chen, Xiaohua Ye
BACKGROUND: Streptococcus pneumoniae (S. pneumoniae) is an important pathogen in causing global morbidity and mortality among children. This study aimed to determine phenotypic and molecular characteristics of S. pneumoniae causing infections in children under five years in China. METHODS: A hospital-based retrospective study was conducted. All 537 S. pneumoniae isolates were tested for antimicrobial susceptibility by E-test method, molecular characteristics including resistance genes, virulence genes and serotypes by multiplex polymerase chain reaction (PCR) method, and sequence types (STs) by sequencing seven housekeeping genes...
December 27, 2017: Vaccine
https://www.readbyqxmd.com/read/29285548/preclinical-evaluation-of-an-18f-trifluoroborate-methionine-derivative-for-glioma-imaging
#15
Xiangyu Yang, Zhibo Liu, Huimin Zhang, Zhu Li, Jeeva P Munasinghe, Gang Niu, Gaojun Teng, Xiaoyuan Chen
PURPOSE: 11C-methionine (MET) is one of the most commonly used amino acid tracers for PET imaging of brain tumors. In this study, we report an 18F-labeled boron-derived methionine analogue, denoted as 18F-B-MET, as a potential substitute of 11C-MET for glioma PET imaging. METHODS: 19F-B-MET was synthesized from readily available chemicals according to our previous publication. For kit development, 19F-B-MET was aliquoted in quantities of 10 nmol for on-demand one-step labeling...
December 29, 2017: European Journal of Nuclear Medicine and Molecular Imaging
https://www.readbyqxmd.com/read/29284419/serotype-distribution-and-antibiotic-resistance-of-streptococcus-pneumoniae-isolates-from-17-chinese-cities-from-2011-to-2016
#16
Chunjiang Zhao, Zongbo Li, Feifei Zhang, Xiaobing Zhang, Ping Ji, Ji Zeng, Bijie Hu, Zhidong Hu, Kang Liao, Hongli Sun, Rong Zhang, Bin Cao, Chao Zhuo, Wei Jia, Yaning Mei, Yunzhuo Chu, Xuesong Xu, Qing Yang, Yan Jin, Quan Fu, Xiuli Xu, Hongling Li, Lijun Wang, Yuxing Ni, Hongjie Liang, Hui Wang
BACKGROUND: Streptococcus pneumoniae, the leading pathogen of bacterial infections in infants and the elderly, is responsible for pneumococcal diseases with severe morbidity and mortality. Emergence of drug-resistant strains presented new challenges for treatment and prevention. Vaccination has proven to be an effective means of preventing pneumococcal infection worldwide. Detailed epidemiological information of antibiotic susceptibilities and serotype distribution will be of great help to the management of pneumococcal infections...
December 29, 2017: BMC Infectious Diseases
https://www.readbyqxmd.com/read/29279284/re-emergence-of-pneumococcal-colonization-by-vaccine-serotype-19f-in-persons-aged-%C3%A2-5-years-after-13-valent-pneumococcal-conjugate-vaccine-introduction-alaska-2008-2013
#17
Prabhu P Gounder, Dana Bruden, Karen Rudolph, Tammy Zulz, Debby Hurlburt, Gail Thompson, Michael G Bruce, Thomas W Hennessy
BACKGROUND: The pneumococcal conjugate vaccine (PCV) was introduced in 2001. Widespread PCV use nearly eradicated pneumococcal colonization by vaccine serotypes. Since 2008, however, colonization by PCV-serotype 19F has increased in Alaska residents. We describe the epidemiology of re-emerging serotype 19F colonization. METHODS: We conducted annual cross-sectional colonization surveys from 2008 to 2013. We recruited children aged <5 years at 2 urban clinics and participants of all ages from Region-A (2 villages), Region-B (4 villages), and Region-C (2 villages)...
December 23, 2017: Vaccine
https://www.readbyqxmd.com/read/29272914/synthesis-and-characterization-of-a-magnetically-active-19f-molecular-beacon
#18
Megan E Dempsey, Hetal D Marble, Tunli Shen, Nicolas L Fawzi, Eric M Darling
Gene expression is used extensively to describe cellular characteristics and behaviors; however, most methods of assessing gene expression are unsuitable for living samples, requiring destructive processes such as fixation or lysis. Recently, molecular beacons have become a viable tool for live-cell imaging of mRNA molecules in situ. Historically, beacon-mediated imaging has been limited to fluorescence-based approaches. We propose the design and synthesis of a novel molecular beacon for magnetic resonance detection of any desired target nucleotide sequence...
December 22, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/29250863/cyclobutanone-mimics-of-intermediates-in-metallo-%C3%AE-lactamase-catalysis
#19
Martine I Abboud, Magda Kosmopoulou, Anthony Krismanich, Jarrod W Johnson, Philip Hinchliffe, Jürgen Brem, Timothy D W Claridge, James Spencer, Christopher Schofield, Gary I Dmitrienko
The most important resistance mechanism to β-lactam antibiotics involves hydrolysis by two β-lactamase categories: the nucleophilic serine (SBL) and the metallo- (MBL) β-lactamases. Cyclobutanones are hydrolytically stable β-lactam analogues with potential to inhibit both SBLs and MBLs. We describe solution and crystallographic studies on the interaction of a cyclobutanone penem analogue with the clinically important MBL SPM-1. NMR experiments using 19F-labeled SPM-1 imply the cyclobutanone binds to SPM-1 with micromolar affinity...
December 17, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29245080/broadband-19f-tocsy-using-burbop-based-spin-lock
#20
Alexander A Marchione, Elizabeth L Diaz
A train of BURBOP universal rotation pulses has been used to generate a spin lock sufficient to observe TOCSY correlations over a 46 kHz 19F spectral window (i.e. 122 ppm on a 9.4 T spectrometer). This spin lock requires lower RF field (γB1 = 15 kHz), and was employed over a wider spectral window, than previously reported DIPSI-2 spin locks. The BURBOP-based spin lock was effected for 80-160 ms periods with a 2% duty cycle without evidence of harm to the RF coil of the probehead. Spectral separation and full set of correlations were obtained for a mixture of perfluorocarbons...
December 5, 2017: Journal of Magnetic Resonance
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