16 April 1992 Study of normal/tumorous tissue fluorescence using a pH-dependent fluorescent probe in vivo
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The pH of interstitial fluid of malignant tumors tends to be lower than that of normal tissue and depressed by glucose administration. This study aimed to evaluate the effectiveness of dual-wavelength ratio fluorometry using a pH-dependent indicator (5,6-carboxyfluorescein: 5,6-CF) for the characterization of normal and tumoral areas in vivo. 5,6-CF has two main characteristics: it has two wavelengths of maximum absorbance (465 and 490 nm) and its fluorescence emission (maximum at 515 nm) increases as a function of pH in the physiological 6 - 7.4 pH range. The experimental study was performed on 31 CDF mice bearing lymphoid leukaemia P388 grafted subcutaneously. The tissular pH values were evaluated from the ratio of the fluorescence intensities (I490/I465) on the basis of a calibration curve linking pH measurements performed intratissularly with a microelectrode and fluorescence intensities ratio values. The fluorescence intensity reached its maximum value at 60 min after 5,6-CF and glucose administration, followed by a plateau (90 min). The ratios remain constant at 1.79 +/- 0.06 for normal tissue and 1.61 +/- 0.07 (without glucose administration) for tumoral tissue. The tumoral tissue ratios decrease down to 1.35 +/- 0.04 after 6 g/kg glucose administration. These results were correlated to the pH measurements in accordance to the calibration curve. This study validates the relevance of dual-wavelength fluorometry using a pH-dependent indicator to characterize in-vivo normal and tumoral tissues after glucose administration.
© (1992) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Serge R. Mordon, Vincent Maunoury, Jean-Marie Devoisselle, Y. Abbas, Denise Coustaut, "Study of normal/tumorous tissue fluorescence using a pH-dependent fluorescent probe in vivo", Proc. SPIE 1648, Fiber Optic Medical and Fluorescent Sensors and Applications, (16 April 1992); doi: 10.1117/12.58298; https://doi.org/10.1117/12.58298

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