Noninvasive measurement of the pH inside the gut by using pH‐sensitive nitroxides. An in vivo EPR study

The use of pH‐sensitive probes permits the measurement of the proton activity in biological systems by EPR spectroscopy. To illustrate the potential of this technique for in vivo purposes, the authors took advantage of the oral administration of nitroxides to monitor the pH value inside the stomach of mice after administration of different antacidics. The results indicate that EPR can be a valuable tool to characterize the pH in vivo in a continuous and noninvasive way.

[1]  J. Jiang,et al.  Low-frequency EPR detection of chromium(V) formation by chromium(VI) reduction in whole live mice. , 1994, Archives of biochemistry and biophysics.

[2]  R. Brasch,et al.  Nitroxyl spin label contrast enhancers for magnetic resonance imaging. Studies of acute toxicity and mutagenesis. , 1984, Investigative radiology.

[3]  J. Jiang,et al.  Detection of short-lived free radicals by low-frequency electron paramagnetic resonance spin trapping in whole living animals. , 1995, Archives of biochemistry and biophysics.

[4]  Tadeusz Walczak,et al.  India ink: A potential clinically applicable EPR oximetry probe , 1994, Magnetic resonance in medicine.

[5]  J. O’Hara,et al.  Oxygen tension in a murine tumor: A combined EPR and MRI study , 1993, Magnetic resonance in medicine.

[6]  J. Dunn,et al.  Use of nitroxides for assessing perfusion, oxygenation, and viability of tissues: In vivo EPR and MRI studies , 1996, Magnetic resonance in medicine.

[7]  Harold M. Swartz,et al.  The application of EPR spectroscopy in the field of pharmacy , 1994 .

[8]  K. Mäder,et al.  Direct and continuous determination of pH values in nontransparent w/o systems by means of EPR spectroscopy , 1995 .

[9]  A. Sandvik,et al.  Review article: the use of gastric acid‐inhibitory drugs—physiological and pathophysiological considerations , 1993, Alimentary pharmacology & therapeutics.

[10]  K. Mäder,et al.  In vivo detection of anthralin-derived free radicals in the skin of hairless mice by low-frequency electron paramagnetic resonance spectroscopy. , 1995, The Journal of investigative dermatology.

[11]  R. Magin,et al.  In vivo localized ESR spectroscopy reflecting metabolism , 1989, Magnetic resonance in medicine.

[12]  B. Gallez,et al.  Mutagenicity of nitroxyl compounds: structure-activity relationships. , 1992, Toxicology letters.

[13]  H. Swartz,et al.  Non-invasive in vivo characterization of release processes in biodegradable polymers by low-frequency electron paramagnetic resonance spectroscopy. , 1996, Biomaterials.

[14]  L. Berliner,et al.  In vivo EPR studies of the metabolic fate of nitrosobenzene in the mouse , 1994, Magnetic resonance in medicine.

[15]  H. Swartz,et al.  Lithium phthalocyanine: a probe for electron paramagnetic resonance oximetry in viable biological systems. , 1993, Proceedings of the National Academy of Sciences of the United States of America.

[16]  I. A. Grigoriev,et al.  Proton exchange in stable nitroxyl radicals. EPR study of the pH of aqueous solutions , 1982 .