A method for calculating the distribution of pH in tissues and a new source of pH error from the 31P-NMR spectrum

The true distribution of the pH in tissues can be determined from the in vivo 31P-nuclear magnetic resonance (NMR) spectrum by converting the parts per million (PPM) axis of the pH responsive resonance to pH using the Henderson-Hasselbalch equation. In addition, the intensity axis of the resonance must be divided by the derivative of the Henderson-Hasselbalch equation to correct for the nonlinear relationship between pH and PPM. This nonlinear relationship causes the apparent center of the resonance in PPM to be dependent not only on the center of the pH distribution but also on its width and distance from the pKa, where Ka is the association constant. Therefore, the pH determined from uncorrected spectra may be in significant error, particularly if the pH distribution is distant from the pKa and is broad. The method was applied to the isolated perfused Morris hepatoma 5123C to determine the distribution of intracellular pH (pHi) using resonances from two intracellular compounds. The two resonances did not report the same pHi unless the spectral data were properly corrected. The method should be of interest to anyone interested in pHi.

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In vivo 31P NMR spectrum of Hymenolepis diminuta and its change on short-term exposure to mebendazole

Molecular and Biochemical Parasitology ◽

10.1016/0166-6851(87)90068-5 ◽

1987 ◽

Vol 22 (1) ◽

pp. 45-54 ◽

Cited By ~ 9

Author(s):

Stewart N. Thompson ◽

Edward G. Platzer ◽

Robert W.K. Lee

Keyword(s):

31P Nmr ◽

Hymenolepis Diminuta ◽

Short Term ◽

Nmr Spectrum ◽

Short Term Exposure

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Effects of ischemia on intracellular sodium and phosphates in the in vivo rat liver

Journal of Applied Physiology ◽

10.1152/jappl.1996.81.3.1395 ◽

1996 ◽

Vol 81 (3) ◽

pp. 1395-1403 ◽

Cited By ~ 17

Author(s):

Z. F. Xia ◽

J. W. Horton ◽

P. Y. Zhao ◽

E. E. Babcock ◽

A. D. Sherry ◽

...

Keyword(s):

Nmr Spectroscopy ◽

Atomic Absorption ◽

Rat Liver ◽

Absorption Spectroscopy ◽

Atomic Absorption Spectroscopy ◽

31P Nmr ◽

Ischemic Injury ◽

Nmr Spectrum ◽

23Na Nmr

Metabolic factors that influence the transition form reversible to irreversible ischemic injury were studied in the rat liver in vivo with 31P-nuclear magnetic resonance (NMR) spectroscopy. Hepatic ischemia for 15, 35, or 65 min was produced by occlusion of the hepatic artery and portal vein in rats. Ischemia caused a rapid decrease in the ATP concentration ([ATP])-to-P(i) concentration ratio and pH within 5 min, but there was little change in these variables detectable by 31P-NMR with longer periods of ischemia. After reperfusion, the [ATP] and P(i) concentration returned toward normal values in livers exposed to 15 or 35 min of ischemia, but 65 min of ischemia were associated with only modest recovery in [ATP], and the [ATP] later decreased. Because the 31P-NMR spectrum was similar after brief compared with prolonged ischemia, it appears that neither ATP depletion, P(i) accumulation, nor acidosis predicts metabolic recovery. Hepatic intracellular NA+ was also measured in separate groups of animals by 23Na-NMR in the presence of a shift agent, thulium (III) 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis (methylene-phosphonate) (TmDOTP5-), and by atomic absorption spectroscopy. Under baseline conditions, the concentration of intracellular Na+ was 15.2 mM by atomic absorption spectroscopy and 16.5 mM by 23Na-NMR. Although the 31P-NMR spectrum responded very rapidly to the onset of ischemia, intracellular Na+ concentration measured by 23Na-NMR increased gradually but steadily at approximately 1.0 mM/min during early (up to 15 min) ischemia. These observations demonstrate that a rise in intracellular Na+ does occur early ischemia, that TmDOTP5- can be applied in vivo for analysis of intracellular Na+ in the ischemic liver, and that 31P-NMR spectroscopy is very sensitive to early ischemic injury.

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Intracellular pH and inorganic phosphate content of heart in vivo: a 31P-NMR study

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1988.255.1.h189 ◽

1988 ◽

Vol 255 (1) ◽

pp. H189-H196 ◽

Cited By ~ 8

Author(s):

L. A. Katz ◽

J. A. Swain ◽

M. A. Portman ◽

R. S. Balaban

Keyword(s):

Intracellular Ph ◽

Inorganic Phosphate ◽

31P Nmr ◽

Respiratory Alkalosis ◽

Distal Portion ◽

Receiver Coil ◽

Canine Heart ◽

Nmr Spectrum ◽

Nmr Study

Studies were performed to determine the contribution of red blood cells to the 31P-nuclear magnetic resonance (NMR) spectrum of the canine heart in vivo and the feasibility of measuring myocardial intracellular phosphate and pH. This was accomplished by replacing whole blood with a perfluorochemical perfusion emulsion blood substitute, Oxypherol, and noting the difference in the 31P-NMR spectrum of the heart. NMR data were collected with a NMR transmitter-receiver coil on the surface of the distal portion of the left ventricle. These studies demonstrated that a small (approximately 10%) contribution from 2,3-diphosphoglycerate (2,3-DPG) and phosphodiesters in the blood could be detected. The magnitude and shift of these blood-borne signals permitted the relative quantification of intracellular inorganic phosphate (Pi) content as well as intracellular pH. Under resting conditions, the intracellular ATP/Pi was 7.0 +/- 0.8 (n = 19). This corresponds to a free intracellular Pi content of approximately 0.8 mumol/g wet wt. The intracellular pH was 7.10 +/- 0.01 (n = 19). Acute respiratory alkalosis and acidosis, with the arterial pH ranging from approximately 7.0 to 7.7, resulted in only small changes in the intracellular pH (approximately 0.1 pH unit). These latter results demonstrate an effective myocardial intracellular proton-buffering mechanism in vivo.

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In vivo 31P NMR studies on experimental cerebral infarction.

The Japanese Journal of Physiology ◽

10.2170/jjphysiol.33.19 ◽

1983 ◽

Vol 33 (1) ◽

pp. 19-28 ◽

Cited By ~ 37

Author(s):

Shoji NARUSE ◽

Soshun TAKADA ◽

Izumi KOIZUKA ◽

Hiroshi WATARI

Keyword(s):

Cerebral Infarction ◽

31P Nmr ◽

Nmr Studies ◽

Experimental Cerebral Infarction

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Observation of myo-inositol 1,2-(cyclic) phosphate in a Morris hepatoma by 31P NMR.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)75882-7 ◽

1987 ◽

Vol 262 (1) ◽

pp. 35-37

Author(s):

R A Graham ◽

R A Meyer ◽

B S Szwergold ◽

T R Brown

Keyword(s):

31P Nmr ◽

Morris Hepatoma ◽

Cyclic Phosphate

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Yolk–shell magnetic composite Fe3O4@Co/Zn-ZIF for MR imaging-guided chemotherapy of tumors in vivo

New Journal of Chemistry ◽

10.1039/d0nj05723a ◽

2021 ◽

Author(s):

Ying Li ◽

Lu-Lu Jiang ◽

Ya-Xian Qiao ◽

Dong Wan ◽

Yan-Feng Huang

Keyword(s):

Mr Imaging ◽

Contrast Enhancement ◽

Magnetic Composite ◽

Loading Capacity ◽

Ph Responsive

The yolk–shell composites Fe3O4@Co/Zn-ZIF exhibited high doxorubicin loading capacity, pH-responsive release characteristics, and strong T2-weighted MR imaging contrast enhancement, and were used for MR imaging-guided chemotherapy of tumors in vivo.

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