Microscopic images of intraspheroidal pH by 1H magnetic resonance chemical shift imaging of pH sensitive indicators.

摘要: We investigate microscopic pH heterogeneity within tumor spheroids using a novel 1H NMR methodology that provides high resolution measurements of intraspheroidal pH. Material and Methods: High images were obtained by chemical shift selective excitation the H2 resonance imidazole added to incubation medium. Imidazole accumulated in space dependent manner. Maps could be transforming pixel (32 × 32$) regional variation intensity into relative scale. Results: Our analysis revealed drastic alterations depending on size spheroid, ca. 0.6 pH units more acidic necrotic core than periphery, for 600 μm diameter. The presence concentric regions having similar was consistently observed. thickness these decreased from pH 7.2 pH 6.8 increased below latter value. Conclusion: observations are compatible with general model spheroid growth where external layers cells active depict alkaline values while inner remain quiescent or evolve core, depicting values.