keyword
MENU ▼
Read by QxMD icon Read
search

CEST

keyword
https://www.readbyqxmd.com/read/29143921/dichloroacetate-induced-intracellular-acidification-in-glioblastoma-in-vivo-detection-using-aacid-cest-mri-at-9-4%C3%A2-tesla
#1
Mohammed Albatany, Alex Li, Susan Meakin, Robert Bartha
Intracellular pH (pHi) plays an important role in the maintenance of normal cell function, and is maintained within a narrow range by the activity of transporters located at the plasma membrane. Modulation of tumor pHi may influence proliferation, apoptosis, chemotherapy resistance, and thermosensitivity. Chemical exchange saturation transfer (CEST) is a novel MRI contrast mechanism that is dependent on cellular pH. Amine and amide concentration-independent detection (AACID) is a recently developed CEST contrast method that is intracellular pH (pHi) weighted...
November 16, 2017: Journal of Neuro-oncology
https://www.readbyqxmd.com/read/29133469/an-invisible-ubiquitin-conformation-is-required-for-efficient-phosphorylation-by-pink1
#2
Christina Gladkova, Alexander F Schubert, Jane L Wagstaff, Jonathan N Pruneda, Stefan M V Freund, David Komander
The Ser/Thr protein kinase PINK1 phosphorylates the well-folded, globular protein ubiquitin (Ub) at a relatively protected site, Ser65. We previously showed that Ser65 phosphorylation results in a conformational change in which Ub adopts a dynamic equilibrium between the known, common Ub conformation and a distinct, second conformation wherein the last β-strand is retracted to extend the Ser65 loop and shorten the C-terminal tail. We show using chemical exchange saturation transfer (CEST) nuclear magnetic resonance experiments that a similar, C-terminally retracted (Ub-CR) conformation also exists at low population in wild-type Ub...
November 13, 2017: EMBO Journal
https://www.readbyqxmd.com/read/29119369/clinical-importance-of-temporal-bone-features-for-the-efficacy-of-contrast-enhanced-sonothrombolysis-a-retrospective-analysis-of-the-nor-sass-trial
#3
Vojtech Novotny, Aliona Nacu, Christopher E Kvistad, Annette Fromm, Gesche F Neckelmann, Andrej N Khanevski, Haakon Tobro, Ulrike Waje-Andreassen, Halvor Naess, Lars Thomassen, Nicola Logallo
Contrast-enhanced sonothrombolysis (CEST) seems to be a safe and promising treatment in acute ischemic stroke. It remains unknown if temporal bone features may influence the efficacy of CEST. We investigated the association between different temporal bone features on admission computed tomography (CT) scan and the outcome in acute ischemic stroke patients included in the randomized Norwegian Sonothrombolysis in Acute Stroke Study (NOR-SASS). Patients diagnosed as stroke mimics and those with infratentorial stroke or with incorrect insonation were excluded...
November 8, 2017: Translational Stroke Research
https://www.readbyqxmd.com/read/29111410/the-z-spectrum-from-human-blood-at-7t
#4
Simon M Shah, Olivier E Mougin, Andrew J Carradus, Nicolas Geades, Richard Dury, William Morley, Penny A Gowland
Chemical Exchange Saturation Transfer (CEST) has been used to assess healthy and pathological tissue in both animals and humans. However, the CEST signal from blood has not been fully assessed. This paper presents the CEST and nuclear Overhauser enhancement (NOE) signals detected in human blood measured via z-spectrum analysis. We assessed the effects of blood oxygenation levels, haematocrit, cell structure and pH upon the z-spectrum in ex vivo human blood for different saturation powers at 7T. The data were analysed using Lorentzian difference (LD) model fitting and AREX (to compensate for changes in T1), which have been successfully used to study CEST effects in vivo...
October 27, 2017: NeuroImage
https://www.readbyqxmd.com/read/29083166/enantiomeric-recognition-of-d-and-l-lactate-by-cest-with-the-aid-of-a-paramagnetic-shift-reagent
#5
Lei Zhang, Andre F Martins, Piyu Zhao, Michael Tieu, David Esteban-Gomez, Gregory T McCandless, Carlos Platas-Iglesias, A Dean Sherry
A previous report demonstrated that EuDO3A can be used as a NMR shift reagent for imaging extracellular lactate produced by cancer cells using CEST imaging. In this work, a series of heptadentate macrocyclic YbDO3A-trisamide complexes with δ-chiral carbons in the three pendant side-arms were examined as shift reagents for lactate detection. High resolution 1H NMR spectra and DFT calculations provided evidence for formation of stereoselective lactate•YbDO3A-trisamide complexes each with a different CEST signature...
October 30, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29068044/contrast-enhanced-sonothrombolysis-in-acute-ischemic-stroke-patients-without-intracranial-large-vessel-occlusion
#6
C E Kvistad, A Nacu, V Novotny, N Logallo, U Waje-Andreassen, H Naess, L Thomassen
BACKGROUND: Contrast-enhanced sonothrombolysis (CEST) leads to a more rapid recanalization in acute ischemic stroke caused by intracranial large-vessel occlusion (LVO). Animal studies have shown that CEST also may be safe and efficient in treating the ischemic microcirculation in the absence of LVO. The exact mechanism behind this treatment effect is not known. We aimed to assess safety and efficacy of CEST in acute ischemic stroke patients included in the Norwegian Sonothrombolysis in Acute Stroke Study (NOR-SASS) without LVO on admission CT angiography (CTA)...
October 25, 2017: Acta Neurologica Scandinavica
https://www.readbyqxmd.com/read/29038382/protonation-of-carboxyl-groups-in-eudota-tetraamide-complexes-results-in-catalytic-prototropic-exchange-and-quenching-of-the-cest-signal
#7
Lei Zhang, Osasere M Evbuomwan, Michael Tieu, Piyu Zhao, Andre F Martins, A Dean Sherry
The CEST properties of EuDOTA-tetraamide complexes bearing pendant carboxylate and carboxyl ethyl esters were measured as a function of pH. The CEST signal from the Eu(3+)-bound water molecule decreased in intensity between pH 8.5 and 4.5 while the proton exchange rates (kex) increased over this same pH range. In comparison, the CEST signal in the corresponding carboxyl ester derivatives was nearly constant. Both observations are consistent with stepwise protonation of the four carboxylic acid groups over this same pH range...
November 28, 2017: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
https://www.readbyqxmd.com/read/29030880/direct-saturation-corrected-chemical-exchange-saturation-transfer-mri-of-glioma-simplified-decoupling-of-amide-proton-transfer-and-nuclear-overhauser-effect-contrasts
#8
Iris Yuwen Zhou, Enfeng Wang, Jerry S Cheung, Dongshuang Lu, Yang Ji, Xiaoan Zhang, Giulia Fulci, Phillip Zhe Sun
PURPOSE: Chemical exchange saturation transfer (CEST) MRI has shown promise in tissue characterization in diseases like stroke and tumor. However, in vivo CEST imaging such as amide proton transfer (APT) MRI is challenging because of concomitant factors such as direct water saturation, macromolecular magnetization transfer, and nuclear overhauser effect (NOE), which lead to a complex contrast in the commonly used asymmetry analysis (MTRasym). Here, we propose a direct saturation-corrected CEST (DISC-CEST) analysis for simplified decoupling and quantification of in vivo CEST effects...
October 13, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29028326/ratiometric-ph-imaging-with-a-co-ii-2-mri-probe-via-cest-effects-of-opposing-ph-dependences
#9
Agnes E Thorarinsdottir, Kang Du, James H P Collins, T David Harris
We report a Co2-based magnetic resonance (MR) probe that enables the ratiometric quantitation and imaging of pH through chemical exchange saturation transfer (CEST). This approach is illustrated in a series of air- and water-stable Co(II)2 complexes featuring CEST-active tetra(carboxamide) and/or hydroxyl-substituted bisphosphonate ligands. For the complex bearing both ligands, variable-pH CEST and NMR analyses reveal highly shifted carboxamide and hydroxyl peaks with intensities that increase and decrease with increasing pH, respectively...
October 30, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29024242/lanthanide-based-t2ex-and-cest-complexes-provide-new-insights-into-the-design-of-ph-sensitive-mri-agents
#10
Lei Zhang, Andre F Martins, Piyu Zhao, Yunkou Wu, Gyula Tircso, Dean Sherry
A series of Eu3+ and Dy3+ DOTA-tetraamide complexes with four appended primary amine groups were prepared and their CEST and T1/T2 relaxation properties measured as a function of pH. The CEST signals in the Eu3+ complexes show a surprisingly strong CEST signal after the pH was reduced from 8 to 5. The opposite trend was observed for the Dy3+ complexes where the r2ex of bulk water protons increased dramatically from ~1.5 mM-1s-1 to ~13 mM-1s-1, while r1 remained unchanged. A fit of the CEST data (Eu3+ complexes) to Bloch theory and the T2 data (Dy3+ complexes) to Swift-Connick theory provided the proton exchange rates as a function of pH...
October 11, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/29024066/a-comparison-of-exogenous-and-endogenous-cest-mri-methods-for-evaluating-in-vivo-ph
#11
Leila R Lindeman, Edward A Randtke, Rachel A High, Kyle M Jones, Christine M Howison, Mark D Pagel
PURPOSE: Extracellular pH (pHe) is an important biomarker for cancer cell metabolism. Acido-chemical exchange saturation transfer (CEST) MRI uses the contrast agent iopamidol to create spatial maps of pHe. Measurements of amide proton transfer exchange rates (kex ) from endogenous CEST MRI were compared to pHe measurements by exogenous acido-CEST MRI to determine whether endogenous kex could be used as a proxy for pHe measurements. METHODS: Spatial maps of pHe and kex were obtained using exogenous acidoCEST MRI and an endogenous CEST MRI analyzed with the omega plot method, respectively, to evaluate mouse kidney, a flank tumor model, and a spontaneous lung tumor model...
October 11, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28989612/inside-information-on-xenon-adsorption-in-porous-organic-cages-by-nmr
#12
Sanna Komulainen, Juho Roukala, Vladimir V Zhivonitko, Muhammad Asadullah Javed, Linjiang Chen, Daniel Holden, Tom Hasell, Andrew Cooper, Perttu Lantto, Ville-Veikko Telkki
A solid porous molecular crystal formed from an organic cage, CC3, has unprecedented performance for the separation of rare gases. Here, xenon was used as an internal reporter providing extraordinarily versatile information about the gas adsorption phenomena in the cage and window cavities of the material. (129)Xe NMR measurements combined with state-of-the-art quantum chemical calculations allowed the determination of the occupancies of the cavities, binding constants, thermodynamic parameters as well as the exchange rates of Xe between the cavities...
August 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28981278/eight-coordinate-stable-fe-ii-complex-as-a-dual-19-f-and-cest-contrast-agent-for-ratiometric-ph-imaging
#13
Kriti Srivastava, Giuseppe Ferrauto, Victor G Young, Silvio Aime, Valérie C Pierre
Accurate mapping of small changes in pH is essential to the diagnosis of diseases such as cancer. The difficulty in mapping pH accurately in vivo resides in the need for the probe to have a ratiometric response so as to be able to independently determine the concentration of the probe in the body independently from its response to pH. The complex Fe(II)-DOTAm-F12 behaves as an MRI contrast agent with dual (19)F and CEST modality. The magnitude of its CEST response is dependent both on the concentration of the complex and on the pH, with a significant increase in saturation transfer between pH 6...
October 5, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28979760/ratiometric-quantitation-of-redox-status-with-a-molecular-fe2-magnetic-resonance-probe
#14
Kang Du, Emily A Waters, T David Harris
We demonstrate the ability of a molecular Fe2 complex to enable magnetic resonance (MR)-based ratiometric quantitation of redox status, namely through redox-dependent paramagnetic chemical exchange saturation transfer (PARACEST). Metalation of a tetra(carboxamide) ligand with Fe(II) and/or Fe(III) in the presence of etidronate ion affords analogous FeII2, Fe(II)Fe(III), and FeIII2 complexes. Both FeII2 and Fe(II)Fe(III) complexes give highly-shifted, sharp, and non-overlapping NMR spectra, with multiple resonances for each complex corresponding to exchangeable carboxamide protons...
June 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28978895/magnetic-resonance-imaging-of-neurotransmitter-related-molecules
#15
Hironaka Igarashi, Satoshi Ueki, Ken Ohno, Masaki Ohkubo, Yuji Suzuki
Molecular imaging implies the method capable of pictorially displaying distribution of target molecules and their relative concentration in space. In clinical medicine, where non-invasiveness is mandatory, diagnostic molecular imaging has been considered virtually identical to positron emission tomography (PET). However, there is another powerful, apparently underutilized molecular imaging, namely, proton magnetic resonance spectroscopic imaging ((1)H-MRSI). The technique can detect target molecules endogenous in brain in virtue of their own specific resonance frequencies (chemical shift) and can create quantitative images of each molecule...
2017: Journal of Nippon Medical School, Nippon Ika Daigaku Zasshi
https://www.readbyqxmd.com/read/28961344/investigation-of-the-contribution-of-total-creatine-to-the-cest-z-spectrum-of-brain-using-a-knockout-mouse-model
#16
Lin Chen, Haifeng Zeng, Xiang Xu, Nirbhay N Yadav, Shuhui Cai, Nicolaas A Puts, Peter B Barker, Tong Li, Robert G Weiss, Peter C M van Zijl, Jiadi Xu
The current study aims to assign and estimate the total creatine (tCr) signal contribution to the Z-spectrum in mouse brain at 11.7 T. Creatine (Cr), phosphocreatine (PCr) and protein phantoms were used to confirm the presence of a guanidinium resonance at this field strength. Wild-type (WT) and knockout mice with guanidinoacetate N-methyltransferase deficiency (GAMT-/-), which have low Cr and PCr concentrations in the brain, were used to assign the tCr contribution to the Z-spectrum. To estimate the total guanidinium concentrations, two pools for the Z-spectrum around 2 ppm were assumed: (i) a Lorentzian function representing the guanidinium chemical exchange saturation transfer (CEST) at 1...
December 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28912676/chemical-exchange-saturation-transfer-mri-signal-loss-of-the-substantia-nigra-as-an-imaging-biomarker-to-evaluate-the-diagnosis-and-severity-of-parkinson-s-disease
#17
Chunmei Li, Min Chen, Xuna Zhao, Rui Wang, Haibo Chen, Wen Su, Shuhua Li, Baohui Lou, Guodong Song, Shuai Zhang, Jintao Zhang, Jinyuan Zhou
The early diagnosis of Parkinson's disease (PD) and the accurate evaluation of disease severity are crucial for intervention and treatment in PD patients. In this study, we applied chemical exchange saturation transfer (CEST) imaging to patients at different stages of PD and explored the clinical value of the CEST signal loss of the substantia nigra as an imaging biomarker of PD. The measured CEST signal intensities (including amide proton transfer-weighted or APTw, and total CEST or CESTtotal) of the substantia nigra in PD patients showed a significantly decreased tendency with PD progression...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28862349/z-spectrum-appearance-and-interpretation-in-the-presence-of-fat-influence-of-acquisition-parameters
#18
Shu Zhang, Jochen Keupp, Xinzeng Wang, Ivan Dimitrov, Ananth J Madhuranthakam, Robert E Lenkinski, Elena Vinogradov
PURPOSE: Chemical exchange saturation transfer (CEST) MRI is increasingly evolving from brain to body applications. One of the known problems in the body imaging is the presence of strong lipid signals. Although their influence on the CEST effect is acknowledged, there was no study that focuses on the interplay among echo time, fat fraction, and Z-spectrum. This study strives to address these points, with the emphasis on the application in the breast. METHODS: Z-spectra were simulated in phase and out of phase of the main fat peak at -3...
September 1, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28846825/fluorine-pseudocontact-shifts-used-for-characterizing-the-protein-ligand-interaction-mode-in-the-limit-of-nmr-intermediate-exchange
#19
Jia Gao, E Liang, Rongsheng Ma, Fudong Li, Yixiang Liu, Jiuyang Liu, Ling Jiang, Conggang Li, Haiming Dai, Jihui Wu, Xuncheng Su, Wei He, Ke Ruan
The characterization of protein-ligand interaction modes becomes recalcitrant in the NMR intermediate exchange regime as the interface resonances are broadened beyond detection. Here, we determined the (19) F low-populated bound-state pseudocontact shifts (PCSs) of mono- and di-fluorinated inhibitors of the BRM bromodomain using a highly skewed protein/ligand ratio. The bound-state (19) F PCSs were retrieved from (19) F chemical exchange saturation transfer (CEST) in the presence of the lanthanide-labeled protein, which was termed the (19) F PCS-CEST approach...
August 28, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28792646/clinical-applications-of-chemical-exchange-saturation-transfer-cest-mri
#20
Kyle M Jones, Alyssa C Pollard, Mark D Pagel
Chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) has been developed and employed in multiple clinical imaging research centers worldwide. Selective radiofrequency (RF) saturation pulses with standard 2D and 3D MRI acquisition schemes are now routinely performed, and CEST MRI can produce semiquantitative results using magnetization transfer ratio asymmetry (MTRasym ) analysis while accounting for B0 inhomogeneity. Faster clinical CEST MRI acquisition methods and more quantitative acquisition and analysis routines are under development...
August 9, 2017: Journal of Magnetic Resonance Imaging: JMRI
keyword
keyword
28346
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"