Uptake and localisation of mTHPC (Foscan®) and its14C-labelled form in normal and tumour tissues of the hamster squamous cell carcinoma model: a comparative study

The aim of this study was to evaluate the pharmacokinetics of meta(tetrahydroxyphenyl)chlorin (mTHPC) on different tissues of interest in a hamster tumour model and to confirm our earlier animal studies on semi-quantitative fluorescence microscopy. The results obtained by three different evaluation methods were compared: in vivo spectrofluorometry, ex vivo fluorescence microscopy and chemical extraction of 14C-labelled mTHPC. Following intracardiac injection of 0.5 mg kg−1 mTHPC, groups of five tumour-bearing animals were used for in situ light-induced fluorescence spectroscopy. Afterwards, the biopsies were taken and snap frozen for fluorescence microscopy. The presence of radioactivity in serum and tissues was determined after chemical digestion in scintillation fluid using a scintillation counter. For each analysed tissue, a good correlation was observed between the three evaluation methods. The highest fluorescence intensity and quantities of mTHPC were observed between 12 and 24 h in liver, kidney, serum, vascular endothelium and advanced neoplasia. The majority of mTHPC was found at around 48 h in smooth muscle and at 96 h in healthy cheek pouch mucosa and early malignant lesions. The lowest level of mTHPC was noted in striated muscle at all times. No selectivity in dye localisation was observed between early squamous cell carcinoma and healthy mucosa. Soon after the injection, a significant selectivity was noted for advanced squamous cell carcinoma as compared to healthy cheek pouch mucosa or striated muscle. A significant difference in mTHPC localisation and quantity was also observed between striated and smooth muscle during the first 48 h following the injection. Finally, this study demonstrated the usefulness of non-invasive in situ spectroscopic measurements to be performed systematically prior to photodynamic therapy as a real-time monitoring for each treated patient in order to individualise and adapt the light dosimetry and avoid over or under treatments

Agricultural Research Bulletins, Nos. 175–184

Volume 15, Bulletins 175-184. (175) Chemistry of Butter Making: II. The Nature of the Fatty Materials in Buttermilk and the significance of Certain Buttermilk Testing Methods; (176) Physiologic Factors Affecting the Germination of Seed Corn; (177) Iowa's Population Prospect; (178) Effects of Lime on the Hydrogen-Ion Concentration and Base Exchange Complex of Gundy Silt Loam; (179) Studies on Acetylmethylcarbinol and Diacetyl in Dairy Products; (180) Disproportionate Subclass Numbers in Tables of Multiple Classification; (181) Passing an Alternating Electric Current Through Food and Fruit Juices; (182) Physiological Behavior of Grimes Golden Apples in Storage; 9183) Bacteriology of Cheese: I. Effect of Pasteurizing the Milk on the Nitrogenous Decomposition in Cheddar Cheese; (184) Cost of Production in Agriculture</p