Importance of volume limitation for tissue redox status measurements using nitroxyl contrast agents: A comparison of X-band EPR bile flow monitoring (BFM) method and 300MHz in vivo EPR measurement

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

“…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.…”

“…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.…”

Effects of selenium deficiency on biological results of X-ray and carbon-ion beam irradiation in mice

“…(40) The decay constants of carbamoyl-PROXYL in bile flow measured by the X-band EPR BFM method were significantly slower in SeD rats than in normal rats. (41) Carbamoyl-PROXYL may enter the liver and be excreted into bile, (41) but does not enter the brain through the blood-brain barrier (BBB). (42) MCP, which was used in the present study for mouse brain redox imaging, passes through the BBB and enters the brain.…”

Brain contrasting ability of blood‐brain‐barrier–permeable nitroxyl contrast agents for magnetic resonance redox imaging

“…For example, 3-carboxy-2,2,5,5-tetramethylpyrrolidine-N-oxyl (CxP, so-called carboxy-PROXYL) cannot pass through the BBB (18). 3-Carbamoyl-2,2,5,5-tetramethylpyrrolidine-Noxyl (CmP, so-called carbamoyl-PROXYL) has slight lipophilicity (23). In addition, 3-methoxy-carbonyl-2,2,5,5tetramethyl-pyrrolidine-N-oxyl (MCP, so-called MC-PROXYL) is an amphiphilic molecule, which can easily pass through the BBB (21,24,25).…”