Kinetics of ALA-induced protoporphyrin IX accumulation in the liver, skin, and tumor of a rat model

Abstract

The protoporphyrin IX (PPIX) levels in rat liver, skin, and tumors in vivo in response to i.p. injection of -amino1evu1inic acid (ALA) were monitored by fluorescence spectroscopy. A pharmacokinetic model describes the PPIX dosimetry.

Photodynamic Therapy of Intracranial Tissues: A Preclinical Comparative Study of Four Different Photosensitizers

“…For ALA-induced PpIX the tumor-to-grey matter uptake ratio was similar at 6 and 24 h after administration, suggesting comparable synthesis and clearance kinetics. 24 In principle, if there are no effects such as saturation of photosensitive binding sites, the specific uptake should be independent of administered dose and, indeed, there was poor correlation between the two for all photosensitizers investigated (see Table 2). It should be noted that the photosensitizer concentration measurements did not discriminate between exogenous and endogenous porphyrins and the photochemical activity of the latter is unknown.…”

“…Brain tumors are the most common solid cancers in the pédiatrie age group, the third leading cause of cancer death in the [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] year age group12 and the sixth most common cause of cancer mortality in the population over the age of 20.3 Furthermore, there appears to be either an increase in the incidence of malignant brain tumors among the elderly population4 and/or an increase in the rate of recognition of brain tumors with improved imaging capabilities.5 In spite of surgical resection and aggressive adjuvant radiotherapy and/or chemotherapy, the prognosis for these patients remains poor.…”