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Determination of intracellular pH and compartmentation using diffusion‐weighted NMR spectroscopy with pH‐sensitive indicators
Author(s) -
Cohen Jack S.,
Motiei Menachem,
Carmi Shani,
Shiperto Dana,
Yefet Odeya,
Ringel Israel
Publication year - 2004
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.20034
Subject(s) - imidazole , intracellular ph , intracellular , extracellular , chemistry , nuclear magnetic resonance spectroscopy , histidine , chemical shift , spectroscopy , diffusion , analytical chemistry (journal) , proton , proton nmr , nuclear magnetic resonance , chromatography , stereochemistry , biochemistry , enzyme , physics , quantum mechanics , thermodynamics
The intracellular pH (pHi) of a series of cancer cell lines was determined using the pH‐sensitive indicators imidazole (Im) or histidine (His) and diffusion‐weighted (DW) proton NMR spectroscopy. The DW method allows the observation at high magnetic field gradient values of only the slow‐moving (intracellular) components, thus ensuring complete separation between intra‐ and extracellular components. Using the chemical shift difference (Δδ) between the imidazole ring C2‐H and C4(5)‐H peaks, we were able to measure the pHi independently of chemical shift standardization. With His, the cell lines gave pHi values of ∼6.5–7.0, whereas with Im, a second, more acidic compartment (pHi = 5.5–5.8) was also observed. An inverse correlation was also found between pHi and the intracellular lactate concentration. This method may be applicable to in vivo pH determinations. Magn Reson Med 51:900–903, 2004. © 2004 Wiley‐Liss, Inc.