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- Xu, Xiang, et al.
(författare)
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The effect of the mTOR inhibitor rapamycin on glucoCEST signal in a preclinical model of glioblastoma
- 2019
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Ingår i: Magnetic Resonance in Medicine. - : Wiley. - 0740-3194. ; 81:6, s. 3798-3807
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The mammalian target of rapamycin is an enzyme that regulates cell metabolism and proliferation. It is up-regulated in aggressive tumors, such as glioblastoma, leading to increased glucose uptake and consumption. It has been suggested that glucose CEST signals reflect the delivery and tumor uptake of glucose. The inhibitor rapamycin (sirolimus) has been applied as a glucose deprivation treatment; thus, glucose CEST MRI could potentially be useful for monitoring the tumor responses to inhibitor treatment. Methods: A human U87-EGFRvIII xenograft model in mice was studied. The mice were treated with a mammalian target of Rapamycin inhibitor, rapamycin. The effect of the treatment was evaluated in vivo with dynamic glucose CEST MRI. Results: Rapamycin treatment led to significant increases (P < 0.001) in dynamic glucose-enhanced signal in both the tumor and contralateral brain as compared to the no-treatment group, namely a maximum enhancement of 3.7% ± 2.3% (tumor, treatment) versus 1.9% ± 0.4% (tumor, no-treatment), 1.7% ± 1.1% (contralateral, treatment), and 1.0% ± 0.4% (contralateral, no treatment). Dynamic glucose-enhanced contrast remained consistently higher in treatment versus no-treatment groups for the duration of the experiment (17 min). This was confirmed with area-under-curve analysis. Conclusion: Increased glucose CEST signal was found after mammalian target of Rapamycin inhibition treatment, indicating potential for dynamic glucose-enhanced MRI to study tumor response to glucose deprivation treatment.
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| 2. |
- Zhou, Jinyuan, et al.
(författare)
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APT-weighted MRI: Techniques, current neuro applications, and challenging issues.
- 2019
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Ingår i: Journal of Magnetic Resonance Imaging. - : Wiley. - 1522-2586 .- 1053-1807.
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Forskningsöversikt (refereegranskat)abstract
- Amide proton transfer‐weighted (APTw) imaging is a molecular MRI technique that generates image contrast based predominantly on the amide protons in mobile cellular proteins and peptides that are endogenous in tissue. This technique, the most studied type of chemical exchange saturation transfer imaging, has been used successfully for imaging of protein content and pH, the latter being possible due to the strong dependence of the amide proton exchange rate on pH. In this article we briefly review the basic principles and recent technical advances of APTw imaging, which is showing promise clinically, especially for characterizing brain tumors and distinguishing recurrent tumor from treatment effects. Early applications of this approach to stroke, Alzheimer's disease, Parkinson's disease, multiple sclerosis, and traumatic brain injury are also illustrated. Finally, we outline the technical challenges for clinical APT‐based imaging and discuss several controversies regarding the origin of APTw imaging signals in vivo.
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