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Your search keyword '"Krishna, Murali"' showing total 13 results
Start Over Author "Krishna, Murali" Journal antioxidants & redox signaling
13 results on '"Krishna, Murali"'

7. Continuous wave EPR oximetric imaging at 300 MHz using radiofrequency power saturation effects

Author

Hama, Yukihiro, Matsumoto, Ken-ichiro, Murugesan, Ramachandran, Subramanian, Sankaran, Devasahayam, Nallathamby, W., Koscielniak Janusz, Hyodo, Fuminori, A., Cook John, B., Mitchell James, and C., Krishna Murali

Abstract

A novel continuous wave (CW), radiofrequency (RF), electron paramagnetic resonance (EPR) oximetric imaging technique is proposed, based on the influence of oxygen concentration on the RF power saturation of the EPR resonance. A linear relationship is demonstrated between the partial oxygen pressure (pO2) and the normalized signal intensity (IN), defined as, IN = (IHP - ILP) / ILP, where ILP and IHP refer to signal intensities at low (PL) and high (PH) RF power levels, respectively. A formula for the determination of pO2, derived on the basis of the experimental results, reliably estimated various oxygen concentrations in a five-tube phantom. This new technique was time-efficient and also avoided the missing angle problem associated with conventional spectral-spatial CW EPR oximetric imaging. In vivo power saturation oximetric imaging in a tumor bearing mouse clearly depicted the hypoxic foci within the tumor.

Published
2007

8. <italic>In Vivo</italic> Application of Proton-Electron Double-Resonance Imaging.

Author

Kishimoto, Shun, Krishna, Murali C., Khramtsov, Valery V., Utsumi, Hideo, and Lurie, David J.

Subjects
*PROTONS, *ELECTRON paramagnetic resonance imaging, *ELECTRON spin polarization, *PARTIAL pressure, *OXIDATION-reduction reaction
Abstract

Significance: Proton-electron double-resonance imaging (PEDRI) employs electron paramagnetic resonance irradiation with low-field magnetic resonance imaging so that the electron spin polarization is transferred to nearby protons, resulting in higher signals. PEDRI provides information about free radical distribution and, indirectly, about the local microenvironment such as partial pressure of oxygen (pO2), tissue permeability, redox status, and acid-base balance. Recent Advances: Local acid-base balance can be imaged by exploiting the different resonance frequency of radical probes between R and RH+ forms. Redox status can also be imaged by using the loss of radical-related signal after reduction. These methods require optimized radical probes and pulse sequences. Critical Issues: High-power radio frequency irradiation is needed for optimum signal enhancement, which may be harmful to living tissue by unwanted heat deposition. Free radical probes differ depending on the purpose of PEDRI. Some probes are less effective for enhancing signal than others, which can reduce image quality. It is so far not possible to image endogenous radicals by PEDRI because low concentrations and broad line widths of the radicals lead to negligible signal enhancement. Future Directions: PEDRI has similarities with electron paramagnetic resonance imaging (EPRI) because both techniques observe the EPR signal, directly in the case of EPRI and indirectly with PEDRI. PEDRI provides information that is vital to research on homeostasis, development of diseases, or treatment responses in vivo. It is expected that the development of new EPR techniques will give insights into novel PEDRI applications and vice versa. Antioxid. Redox Signal. 28, 1345–1364. [ABSTRACT FROM AUTHOR]

Published
2018
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10. In Vivo Imaging of Tumor Physiological, Metabolic, and Redox Changes in Response to the Anti-Angiogenic Agent Sunitinib: Longitudinal Assessment to Identify Transient Vascular Renormalization

Author

Matsumoto, Shingo, primary, Saito, Keita, additional, Takakusagi, Yoichi, additional, Matsuo, Masayuki, additional, Munasinghe, Jeeva P., additional, Morris, Herman D., additional, Lizak, Martin J., additional, Merkle, Hellmut, additional, Yasukawa, Keiji, additional, Devasahayam, Nallathamby, additional, Suburamanian, Sankaran, additional, Mitchell, James B., additional, and Krishna, Murali C., additional

Published
2014
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