The effect of blood flow modification on intra- and extracellular pH measured by 31P magnetic resonance spectroscopy in murine tumours
Intra- and extracellular pH (pHi and pHe) were measured simultaneously by 31P magnetic resonance spectroscopy (MRS) in CaNT tumours before and after blood flow modification. Before modification, pHi was 7.1 +/- 0.09 (n = 11) and pHe [measured with an MRS-visible extracellular marker, 3-aminopropyl p...
Saved in:
Published in | British journal of cancer Vol. 72; no. 4; pp. 905 - 911 |
---|---|
Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Basingstoke
Nature Publishing Group
01.10.1995
|
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Intra- and extracellular pH (pHi and pHe) were measured simultaneously by 31P magnetic resonance spectroscopy (MRS) in CaNT tumours before and after blood flow modification. Before modification, pHi was 7.1 +/- 0.09 (n = 11) and pHe [measured with an MRS-visible extracellular marker, 3-aminopropyl phosphonate (3-APP)] was 6.7 +/- 0.05 (n = 8). Chemical shift imaging and localised MRS experiments showed that the 3-APP signal was only from the tumour, not surrounding tissue. After modification by vascular occlusion, independent of whether tumours were maintained at room temperature (22-24 degrees C) or kept warm (33-35 degrees C), there was a decrease in pHi and pHe with pHi decreasing to a greater extent. Qualitatively similar results were found using flavone acetic acid (FAA) as a blood flow modifier; only four out of nine tumours responded to FAA. Concomitant with the reduction of the pH gradient after modification was a decrease in the phosphorylation state of the adenine nucleotides measured either as ATP/Pi by MRS or [ATP]/[ADP][P(i)] in tumour extracts. These results indicate that the intracellular uptake of chemotherapeutic drugs which are dependent on the transmembrane pH gradient will not be enhanced in cells made ischaemic as a result of vascular shutdown. |
---|---|
Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0007-0920 1532-1827 |
DOI: | 10.1038/bjc.1995.431 |