keyword
https://read.qxmd.com/read/38243648/reproducibility-of-3d-ph-weighted-chemical-exchange-saturation-transfer-contrast-in-the-healthy-cervical-spinal-cord
#21
JOURNAL ARTICLE
Alicia E Cronin, Patrick Liebig, Sarah A Detombe, Neil Duggal, Robert Bartha
Spinal cord ischemia and hypoxia can be caused by compression, injury, and vascular alterations. Measuring ischemia and hypoxia directly in the spinal cord noninvasively remains challenging. Ischemia and hypoxia alter tissue pH, providing a physiologic parameter that may be more directly related to tissue viability. Chemical exchange saturation transfer (CEST) is an MRI contrast mechanism that can be made sensitive to pH. More specifically, amine/amide concentration independent detection (AACID) is a recently developed endogenous CEST contrast that has demonstrated sensitivity to intracellular pH at 9...
January 19, 2024: NMR in Biomedicine
https://read.qxmd.com/read/38239047/tumor-therapy-by-targeting-extracellular-hydroxyapatite-using-novel-drugs-a-paradigm-shift
#22
JOURNAL ARTICLE
Mohammed N Tantawy, J Oliver McIntyre, Fiona Yull, M Wade Calcutt, Dmitry S Koktysh, Andrew J Wilson, Zhongliang Zu, Jeff Nyman, Julie Rhoades, Todd E Peterson, Daniel Colvin, Lisa J McCawley, Jerri M Rook, Barbara Fingleton, Marta Ann Crispens, Ronald D Alvarez, John C Gore
BACKGROUND: It has been shown that tumor microenvironment (TME) hydroxyapatite (HAP) is typically associated with many malignancies and plays a role in tumor progression and growth. Additionally, acidosis in the TME has been reported to play a key role in selecting for a more aggressive tumor phenotype, drug resistance and desensitization to immunotherapy for many types of cancers. TME-HAP is an attractive target for tumor detection and treatment development since HAP is generally absent from normal soft tissue...
January 18, 2024: Cancer Medicine
https://read.qxmd.com/read/38236785/ph-mapping-of-gliomas-using-quantitative-chemical-exchange-saturation-transfer-mri-quasi-steady-state-spillover-and-mt-corrected-omega-plot-analysis
#23
JOURNAL ARTICLE
Ying Liu, Yin Wu, Yang Ji, Botao Zhao, Ziyi Jin, Shenghong Ju, Ying-Hua Chu, Patrick Alexander Liebig, He Wang, Cong Li, Xiao-Yong Zhang
BACKGROUND: Quantitative in-situ pH mapping of gliomas is important for therapeutic interventions, given its significant association with tumor progression, invasion, and metastasis. Although chemical exchange saturation transfer (CEST) offers a noninvasive way for pH imaging based on the pH-dependent exchange rate (ksw ), the reliable quantification of ksw in glioma remains constrained due to technical challenges. PURPOSE: To quantify the pH of gliomas by measuring the proton exchange rate through optimized omega plot analysis...
January 18, 2024: Journal of Magnetic Resonance Imaging: JMRI
https://read.qxmd.com/read/38224670/a-generalized-qucesop-method-with-evaluating-cest-peak-overlap
#24
JOURNAL ARTICLE
Yi Wang, Yi-Xuan Sun, Qiu-Yu Yang, Jia-Hong Gao
The overlapping peaks of the target chemical exchange saturation transfer (CEST) solutes and other unknown CEST solutes affect the quantification results and accuracy of the chemical exchange parameters-the fractional concentration, <mml:math xmlns:mml="https://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:mrow><mml:msub><mml:mi>f</mml:mi> <mml:mi>b</mml:mi></mml:msub> </mml:mrow> <mml:annotation>$$ {f}_{\mathrm{b}} $$</mml:annotation></mml:semantics> </mml:math> , exchange rate, <mml:math xmlns:mml="https://www...
January 15, 2024: NMR in Biomedicine
https://read.qxmd.com/read/38221646/transient-excited-states-of-the-metamorphic-protein-mad2-and-their-implications-for-function
#25
JOURNAL ARTICLE
Shefali Jain, Ashok Sekhar
The spindle checkpoint complex is a key surveillance mechanism in cell division that prevents premature separation of sister chromatids. Mad2 is an integral component of this spindle checkpoint complex that recognizes cognate substrates such as Mad1 and Cdc20 in its closed (C-Mad2) conformation by fastening a "seatbelt" around short peptide regions that bind to the substrate recognition site. Mad2 is also a metamorphic protein that adopts not only the fold found in C-Mad2, but also a structurally distinct open conformation (O-Mad2) which is incapable of binding substrates...
January 14, 2024: Proteins
https://read.qxmd.com/read/38173081/dual-signal-chemical-exchange-saturation-transfer-dusi-cest-an-efficient-strategy-for-visualizing-drug-delivery-monitoring-in-living-cells
#26
JOURNAL ARTICLE
Chenlu Yuan, Qianni Guo, Qingbin Zeng, Yaping Yuan, Weiping Jiang, Yuqi Yang, Louis-S Bouchard, Chaohui Ye, Xin Zhou
We report a dual-signal chemical exchange saturation transfer (Dusi-CEST) strategy for drug delivery and detection in living cells. The two signals can be detected by operators in complex environments. This strategy is demonstrated on a cucurbit[6]uril (CB[6]) nanoparticle probe, as an example. The CB[6] probe is equipped with two kinds of hydrophobic cavities: one is found inside CB[6] itself, whereas the other exists inside the nanoparticle. When the probe is dispersed in aqueous solution as part of a hyperpolarized 129 Xe NMR experiment, two signals appear at two different chemical shifts (100 and 200 ppm)...
January 3, 2024: Analytical Chemistry
https://read.qxmd.com/read/38169015/beyond-slow-two-state-protein-conformational-exchange-using-cest-applications-to-three-state-protein-interconversion-on-the-millisecond-timescale
#27
JOURNAL ARTICLE
Ved Prakash Tiwari, Debajyoti De, Nemika Thapliyal, Lewis E Kay, Pramodh Vallurupalli
Although NMR spectroscopy is routinely used to study the conformational dynamics of biomolecules, robust analyses of the data are challenged in cases where exchange is more complex than two-state, such as when a 'visible' major conformer exchanges with two 'invisible' minor states on the millisecond timescale. It is becoming increasingly clear that chemical exchange saturation transfer (CEST) NMR experiments that were initially developed to study systems undergoing slow interconversion are also sensitive to intermediate-fast timescale biomolecular conformational exchange...
January 3, 2024: Journal of Biomolecular NMR
https://read.qxmd.com/read/38151582/spatiotemporal-dynamics-of-neuroinflammation-relate-to-behavioral-recovery-in-rats-with-spinal-cord-injury
#28
JOURNAL ARTICLE
Chaoqi Mu, Jamie L Reed, Feng Wang, M Noor Tantawy, John C Gore, Li Min Chen
PURPOSE: The degree and dynamic progression of neuroinflammation after traumatic spinal cord injuries (SCI) are crucial determinants of the severity of injury and potential for recovery. We used Positron Emission Tomography (PET) to monitor neuroinflammation longitudinally, correlating it with Chemical Exchange Saturation Transfer (CEST) Magnetic Resonance Imaging (MRI) and behavior in contusion-injured rats. These studies help validate CEST metrics and confirm how imaging may be used to evaluate the efficacy of therapies and understand their mechanisms of action...
December 27, 2023: Molecular Imaging and Biology: MIB: the Official Publication of the Academy of Molecular Imaging
https://read.qxmd.com/read/38149988/imaging-of-brain-clearance-pathways-via-mri-assessment-of-the-glymphatic-system
#29
JOURNAL ARTICLE
Yi He, Jitian Guan, Lingfeng Lai, Xiaolei Zhang, Beibei Chen, Xueqing Wang, Renhua Wu
Glymphatic clearance dysfunction may play an important role in a variety of neurodegenerative diseases and the progression of ageing. However, in vivo imaging of the glymphatic system is challenging. In this study, we describe an MRI method based on chemical exchange saturation transfer (CEST) of the Angiopep-2 probe to visualize the clearance function of the glymphatic system. We injected rats with Angiopep-2 via the tail vein and performed in vivo MRI at 7 T to track differences in Angiopep-2 signal changes; we then applied the same principles in a bilateral deep cervical lymph node ligation rat model and in ageing rats...
December 26, 2023: Aging
https://read.qxmd.com/read/38140034/novel-nanoprobe-with-combined-ultrasonography-chemical-exchange-saturation-transfer-magnetic-resonance-imaging-for-precise-diagnosis-of-tumors
#30
JOURNAL ARTICLE
Jieqiong Ding, Liu He, Lin Yang, Liyuan Cheng, Zhiwei Zhao, Binhua Luo, Yanlong Jia
Given that cancer mortality is usually due to a late diagnosis, early detection is crucial to improve the patient's results and prevent cancer-related death. Imaging technology based on novel nanomaterials has attracted much attention for early-stage cancer diagnosis. In this study, a new block copolymer, poly(ethylene glycol)-poly(l-lactide) diblock copolymer (PEG-PLLA), was synthesized by the ring-opening polymerization method and thoroughly characterized using Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (H-NMR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA)...
November 28, 2023: Pharmaceutics
https://read.qxmd.com/read/38114069/a-rapid-method-for-phosphocreatine-weighted-imaging-in-muscle-using-double-saturation-power-chemical-exchange-saturation-transfer
#31
JOURNAL ARTICLE
Malvika Viswanathan, Yashwant Kurmi, Zhongliang Zu
Monitoring the variation in phosphocreatine (PCr) levels following exercise provides valuable insights into muscle function. Chemical exchange saturation transfer (CEST) has emerged as a sensitive method with which to measure PCr levels in muscle, surpassing conventional MR spectroscopy. However, existing approaches for quantifying PCr CEST signals rely on time-consuming fitting methods that require the acquisition of the entire or a section of the CEST Z-spectrum. Additionally, traditional fitting methods often necessitate clear CEST peaks, which may be challenging to obtain at low magnetic fields...
December 19, 2023: NMR in Biomedicine
https://read.qxmd.com/read/38113906/corrections-for-rabi-oscillations-in-cardiac-chemical-exchange-saturation-transfer-mri-under-the-influence-of-very-short-preparation-pulses
#32
JOURNAL ARTICLE
Daniel Schache, Ajay Peddi, Ali Nahardani, Cornelius Faber, Verena Hoerr
Very short chemical exchange saturation transfer (CEST) pulses are beneficial in cardiac continuous wave (cw) CEST MRI, especially in small animals because of their rapid heartbeat; however, they result in signal modulations caused by Rabi oscillations. Therefore, we implemented two different filter techniques, DOwnsampling by SEparation of CEST spectrum into two parts (DOSE) and time domain (TD)-based filtering, to correct for these signal corruptions, allowing a reliable quantification of glucose-weighted CEST (glucoCEST) MRI contrast...
December 19, 2023: NMR in Biomedicine
https://read.qxmd.com/read/38106319/assessment-of-rhabdomyolysis-induced-acute-kidney-injury-with-chemical-exchange-saturation-transfer-magnetic-resonance-imaging
#33
JOURNAL ARTICLE
Qianqian Zhang, Quan Tao, Yuanyao Xie, Zelong Chen, Erdmann Seeliger, Thoralf Niendorf, Wufan Chen, Yanqiu Feng
BACKGROUND: Rhabdomyolysis (RM)-induced acute kidney injury (AKI) is a common renal disease with low survival rate and inadequate prognosis. In this study, we investigate the feasibility of chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) for assessing the progression of RM-induced AKI in a mouse model. METHODS: AKI was induced in C57BL/6J mice via intramuscular injection of 7.5 mL/kg glycerol (n=30). Subsequently, serum creatinine (SCr), blood urea nitrogen (BUN), and hematoxylin-eosin (HE) and Masson staining, were performed...
December 1, 2023: Quantitative Imaging in Medicine and Surgery
https://read.qxmd.com/read/38106293/investigation-of-relayed-nuclear-overhauser-enhancement-effect-at-1-6-ppm-in-an-ischemic-stroke-model
#34
JOURNAL ARTICLE
Lee Sze Foo, James R Larkin, Brad A Sutherland, Kevin J Ray, Wun-She Yap, Choon-Hian Goh, Yan Chai Hum, Khin Wee Lai, George Harston, Yee Kai Tee
BACKGROUND: When an ischemic stroke happens, it triggers a complex signalling cascade that may eventually lead to neuronal cell death if no reperfusion. Recently, the relayed nuclear Overhauser enhancement effect at -1.6 ppm [NOE(-1.6 ppm)] has been postulated may allow for a more in-depth analysis of the ischemic injury. This study assessed the potential utility of NOE(-1.6 ppm) in an ischemic stroke model. METHODS: Diffusion-weighted imaging, perfusion-weighted imaging, and chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) data were acquired from five rats that underwent scans at 9...
December 1, 2023: Quantitative Imaging in Medicine and Surgery
https://read.qxmd.com/read/38098703/improving-the-potential-of-paracest-through-magnetic-coupling-induced-line-sharpening
#35
JOURNAL ARTICLE
Xin Guo, Lei Zhang, Jiesheng Hu, Balázs Szilágyi, Meng Yu, Shizhen Chen, Gyula Tircsó, Xin Zhou, Jun Tao
Magnetic coupling between paramagnetic centers is a crucial phenomenon in the design of efficient MRI contrast agents. In this study, we investigate the paraCEST properties and magnetic coupling effects of a novel homodinuclear Ni(ii) complex, 1, containing a Robson type macrocyclic ligand. A thorough analysis of the complex's electronic and magnetic properties revealed that the magnetic coupling effect reduces the transverse relaxation rate and enhances the sharpness of the proton resonances, leading to enhanced CEST efficiency...
December 13, 2023: Chemical Science
https://read.qxmd.com/read/38098340/machine-learning-based-amide-proton-transfer-imaging-using-partially-synthetic-training-data
#36
JOURNAL ARTICLE
Malvika Viswanathan, Leqi Yin, Yashwant Kurmi, Zhongliang Zu
PURPOSE: Machine learning (ML) has been increasingly used to quantify CEST effect. ML models are typically trained using either measured data or fully simulated data. However, training with measured data often lacks sufficient training data, whereas training with fully simulated data may introduce bias because of limited simulations pools. This study introduces a new platform that combines simulated and measured components to generate partially synthetic CEST data, and to evaluate its feasibility for training ML models to predict amide proton transfer (APT) effect...
December 14, 2023: Magnetic Resonance in Medicine
https://read.qxmd.com/read/38098305/specific-and-rapid-guanidinium-cest-imaging-using-double-saturation-power-and-quass-analysis-in-a-rodent-model-of-global-ischemia
#37
JOURNAL ARTICLE
Iris Y Zhou, Yang Ji, Yu Zhao, Malvika Viswanathan, Phillip Zhe Sun, Zhongliang Zu
PURPOSE: Guanidinium CEST is sensitive to metabolic changes and pH variation in ischemia, and it can offer advantages over conventional pH-sensitive amide proton transfer (APT) imaging by providing hyperintense contrast in stroke lesions. However, quantifying guanidinium CEST is challenging due to multiple overlapping components and a close frequency offset from water. This study aims to evaluate the applicability of a new rapid and model-free CEST quantification method using double saturation power, termed DSP-CEST, for isolating the guanidinium CEST effect from confounding factors in ischemia...
December 14, 2023: Magnetic Resonance in Medicine
https://read.qxmd.com/read/38086821/metabolic-brain-imaging-with-glucosamine-cest-mri-in-vivo-characterization-and-first-insights
#38
JOURNAL ARTICLE
Michal Rivlin, Or Perlman, Gil Navon
The utility of chemical exchange saturation transfer (CEST) MRI for monitoring the uptake of glucosamine (GlcN), a safe dietary supplement, has been previously demonstrated in detecting breast cancer in both murine and human subjects. Here, we studied and characterized the detectability of GlcN uptake and metabolism in the brain. Following intravenous GlcN administration in mice, CEST brain signals calculated by magnetization transfer ratio asymmetry (MTRasym) analysis, were significantly elevated, mainly in the cortex, hippocampus, and thalamus...
December 12, 2023: Scientific Reports
https://read.qxmd.com/read/38073061/fluid-suppression-in-amide-proton-transfer-weighted-aptw-cest-imaging-new-theoretical-insights-and-clinical-benefits
#39
JOURNAL ARTICLE
Jan-Rüdiger Schüre, Stefano Casagranda, Maria Sedykh, Patrick Liebig, Christos Papageorgakis, Laura Mancini, Sotirios Bisdas, Lucia Nichelli, Nandor Pinter, Laszlo Mechtler, Ramin Jafari, Nathalie Boddaert, Volodia Dangouloff-Ros, Julie Poujol, Manuel Schmidt, Arnd Doerfler, Moritz Zaiss
PURPOSE: Amide proton transfer-weighted (APTw) MRI at 3T provides a unique contrast for brain tumor imaging. However, APTw imaging suffers from hyperintensities in liquid compartments such as cystic or necrotic structures and provides a distorted APTw signal intensity. Recently, it has been shown that heuristically motivated fluid suppression can remove such artifacts and significantly improve the readability of APTw imaging. THEORY AND METHODS: In this work, we show that the fluid suppression can actually be understood by the known concept of spillover dilution, which itself can be derived from the Bloch-McConnell equations in comparison to the heuristic approach...
December 10, 2023: Magnetic Resonance in Medicine
https://read.qxmd.com/read/38066225/improved-postprocessing-of-dynamic-glucose-enhanced-cest-mri-for-imaging-brain-metastases-at-3%C3%A2-t
#40
JOURNAL ARTICLE
Yulun Wu, Sophie H A E Derks, Tobias C Wood, Erik de Blois, Astrid A M van der Veldt, Marion Smits, Esther A H Warnert
BACKGROUND: Dynamic glucose-enhanced (DGE) chemical exchange saturation transfer (CEST) has the potential to characterize glucose metabolism in brain metastases. Since the effect size of DGE CEST is small at 3 T (< 1%), measurements of signal-to-noise ratios are challenging. To improve DGE detection, we developed an acquisition pipeline and extended image analysis for DGE CEST on a hybrid 3-T positron emission tomography/magnetic resonance imaging system. METHODS: This cross-sectional study was conducted after local ethical approval...
December 8, 2023: European Radiology Experimental
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