Competition of nitroxyl contrast agents as an in vivo tissue redox probe: Comparison of pharmacokinetics by the bile flow monitoring (BFM) and blood circulating monitoring (BCM) methods using X‐band EPR and simulation of decay profiles

Okajo, Aya; Matsumoto, Ken‐ichiro; Mitchell, James B.; Krishna, Murali C.; Endo, Kazutoyo

doi:10.1002/mrm.20958

Cited by 16 publications

(20 citation statements)

References 26 publications

(44 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…EPR signal decay behavior of carbamoyl-PROXYL and TEMPOL in bile and blood showed a distinctive biphasic trend, i.e., an initial fast decay phase and second slow decay phase, as observed previously. 22) Natural logarithmic values of the concentration (mM) of carbamoyl-PROXYL ( Fig. 1) and TEMPOL (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Carbamoyl-PROXYL and TEMPOL, which are probably two of the most popular nitroxyl radicals as in vivo redox probe in our and other past papers, [9][10][11]17,22,23) were also used in this paper. EPR signal decay behavior of carbamoyl-PROXYL and TEMPOL in bile and blood showed a distinctive biphasic trend, i.e., an initial fast decay phase and second slow decay phase, as observed previously.…”

Section: Resultsmentioning

confidence: 99%

“…Understanding the detailed mechanisms of in vivo redox reactions of nitroxyl radicals is quite important to avoid misleading information. In the present study, pharmacokinetics and in vivo redox behaviors of nitroxyl radicals under an oxidative atmosphere in tissue and blood were investigated separately by the EPR bile flow monitoring (BFM) 22,23) and blood circulation monitoring (BCM) 24) analysis. Differences between redox mechanisms in intra-and extracellular volume are discussed herein.…”

Section: ·ϫmentioning

confidence: 99%

See 2 more Smart Citations

Intracellular and Extracellular Redox Environments Surrounding Redox-Sensitive Contrast Agents under Oxidative Atmosphere

Okajo

Sarangapani³

et al. 2009

Biological & Pharmaceutical Bulletin

Self Cite

View full text Add to dashboard Cite

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: ·ϫmentioning

confidence: 99%

See 1 more Smart Citation

Intracellular and Extracellular Redox Environments Surrounding Redox-Sensitive Contrast Agents under Oxidative Atmosphere

Okajo

Sarangapani³

et al. 2009

Biological & Pharmaceutical Bulletin

Self Cite

View full text Add to dashboard Cite

show abstract

“…On the other hand, Carbamoyl-PROXYL is reported to be partially membrane-permeable and reflects both the extracellular (membrane surface) and the intracellular local redox status, where the former is predominant (31,32). NAD(P)H oxidase located in vessels is considered to be the major source of ROS (18), and it may affect Carbamoyl-PROXYL halflives.…”

Section: Discussionmentioning

confidence: 99%

In Vivo Imaging of Renal Redox Status during Azelnidipine Treatment

Hirayama

Ueda²,

Oteki

et al. 2008

Hypertens Res

View full text Add to dashboard Cite

“…[1][2][3][4][5][6] The enzymatic or chemical reduction system reduces nitroxyl radicals to the corresponding hydroxylamine, [7][8][9][10][11][12] enabling us to estimate the redox status in vivo. Hypoxic conditions in the tumor, [13][14][15] biological reducing agents, 16,17) and oxidative stresses accompanying the synthesis of superoxide and/or hydroxyl radical [18][19][20] can enhance the reduction of nitroxyl radicals in vivo.…”

mentioning

confidence: 99%

Utility Decay Rates of T1-Weighted Magnetic Resonance Imaging Contrast Based on Redox-Sensitive Paramagnetic Nitroxyl Contrast Agents

Matsumoto

2009

Biological & Pharmaceutical Bulletin

Self Cite

View full text Add to dashboard Cite

Nitroxyl radicals have been widely used as a free radical probe for electron paramagnetic resonance (EPR) spectroscopy and EPR imaging (EPRI) to investigate in vivo redox conditions. [1][2][3][4][5][6] The enzymatic or chemical reduction system reduces nitroxyl radicals to the corresponding hydroxylamine, [7][8][9][10][11][12] enabling us to estimate the redox status in vivo. Hypoxic conditions in the tumor, [13][14][15] biological reducing agents, 16,17) and oxidative stresses accompanying the synthesis of superoxide and/or hydroxyl radical [18][19][20] can enhance the reduction of nitroxyl radicals in vivo. In contrast, oxidative conditions in a tissue could apparently decrease the in vivo reduction rate of nitroxyl radicals due to the re-oxidation of hydroxylamine to the original nitroxyl radical. 21)The feasibility of nitroxyl radicals as T 1 -enhancing magnetic resonance imaging (MRI) contrast agents has been described since the early 1980s. 22,23) Since the T 1 relaxation of protons can be affected by paramagnetic nitroxyl electron spin, changing the MRI contrast before and after administration of the nitroxyl contrast agent can reflect the amount of nitroxyl contrast agent in addition to providing simultaneous anatomical mapping, similar to Gd 3ϩ . Despite a number of pharmacokinetic studies, 7,24,25) rapid in vivo reduction of the nitroxyl contrast agent was not as useful as an MRI contrast agent in early 1980s. 26)At that time, relatively low T 1 relaxivity of nitroxyl contrast agents was another problem for obtaining clinically and/or experimentally utilizable T 1 -contrast enhancement. Recently, high-power magnet MRI instrumentation, such as 4.7 T, with a T 1 -weighted spoiled gradient echo (SPGR) pulse sequence has enabled us to take a fresh look at the feasibility of employing nitroxyl radicals as MRI contrast agents. [27][28][29] The redox status of the tumor and normal tissue can be reflected in the time course of T 1 contrast after the injection of a paramagnetic nitroxyl contrast agent to an experimental animal.Gradient echo (GE)-based T 1 -weighted contrast imaging is fast and is suitable for dynamic imaging, although T 1 -weighted MRI contrast can not be utilized to quantify the amount of contrast agent directly. The pseudo decay rate calculated based on decreasing T 1 -weighted MRI contrast can show a similar value to the decay rate obtained by EPR measurement when an identical phantom sample is measured by both methods. 27,28) In vivo experiments which compared the decay rates of a nitroxyl contrast agent between normal and tumor tissues of a mouse also showed similar results between EPRI and MRI experiments. 27,28) Several problems on EPRI, such as lack of anatomical information, low spatial resolution, low temporal resolution, and relatively small sample volume, can be solved using MRI; however, the pseudo decay rate obtained based on T 1 -weighted MRI contrast is not a theoretically true decay rate because the detection of nitroxyl radical using MRI is indirect, based on the enhancement o...

show abstract

Competition of nitroxyl contrast agents as an in vivo tissue redox probe: Comparison of pharmacokinetics by the bile flow monitoring (BFM) and blood circulating monitoring (BCM) methods using X‐band EPR and simulation of decay profiles

Cited by 16 publications

References 26 publications

Intracellular and Extracellular Redox Environments Surrounding Redox-Sensitive Contrast Agents under Oxidative Atmosphere

Intracellular and Extracellular Redox Environments Surrounding Redox-Sensitive Contrast Agents under Oxidative Atmosphere

In Vivo Imaging of Renal Redox Status during Azelnidipine Treatment

Utility Decay Rates of T1-Weighted Magnetic Resonance Imaging Contrast Based on Redox-Sensitive Paramagnetic Nitroxyl Contrast Agents

Contact Info

Product

Resources

About