Yoshinori Nakagawa

In vivo and in vitro activation of macrophages with a cyanine photosensitizing dye, platonin

A cyanine photosensitizing dye, platonin, is a potent macrophage-activating agent. Four days after the administration to mice of small amounts of platonin (20–40 ng/mouse), peritoneal macrophages exhibited greatly enhanced Fc-receptor-mediated phagocytic and superoxide-generating capacities. Much higher doses (more than 3000 ng/mouse) did not have this effect. Photodynamic experiments for macrophage activation were performed by exposing mouse peritoneal cells (mixture of macrophages and B and T lymphocytes) to white fluorenscent light (3 J m−2s−1) in media containing various low concentrations of platonin. A short exposure to white fluorescent light (5 s, 15 J m−2) of peritoneal cells in a medium containing 3 ng platonin/ml produced a maximal level of phagocytic capacity of macrophages. Although platonin absorbs light poorly at wavelengths longer than 630 nm, the region of the spectrum in which the tissues are transparent allows reasonable penetration of light. Thus, we designed experiments in which peritoneal cells were exposed to a red fluorescent light (0.5 J m−2s−1). In a medium containing 10 ng platonin/ml with 15 J m−2 red light, a markedly enhanced ingestion activity of macrophages was observed. Photodynamic treatment of peritoneal macrophages alone did not activate macrophages. Thus, participation of nonadherent cells is required for photodynamic activation of macrophages, implying that a macrophage-activating factor is generated within the nonadherent cells and transmitted to macrophages.

Design of Novel Hypoxia-Targeting IDO Hybrid Inhibitors Conjugated with an Unsubstituted L-TRP as an IDO Affinity Moiety

We presented here design, syntheses and inhibitory activities of novel hypoxia-targeting IDO hybrid inhibitors conjugated with an unsubstituted L-Trp as an IDO affinity moiety without inhibitor 1MT, such as L-Trp-TPZ hybrids 1 (TX-2274), 2 (UTX-3), 3 (UTX-4), and 4 (UTX-2). TPZ-monoxide hybrids 1 and 3 were good competitive IDO inhibitors, while TPZ hybrids 2 and 4 were uncompetitive IDO inhibitors. Among them TPZ-monoxide hybrid 1 have the strongest IDO inhibitory activity. It suggests that TPZ-monoxide hybrids 1 and 3 are able to bind the active site of IDO, TPZ hybrids 2 and 4 are able to bind the enzyme-substrate complex. We proposed the possible mechanism of action of TPZ hybrid 2 that may first affect as a hypoxic cytotoxin, and then metabolized to TPZ-monoxide hybrid 1, which may do as an IDO inhibitor more effectively than its parent TPZ hybrid 2.

Assay for KANKOH-SO No. 401 by Titration Method by Tetraphenylboron with Bromophenol Blue as an Indicator Reagent

A simple and rapid titration method for KANKOH-SO No. 401 has been developed. KANKOH-SO No. 401 reacted with bromophenolblue (BPB) and formed a complex, which was extacted to chloroform. When tetraphenylborone (TPB) was added to this solution, TPB and KANKOH-SO No. 401 interacted quantitatively and BPB was found to be released from chloroform phase to water.Therefore, condition were established to determine KANKOH-SO No. 401 by titration method with TPB in the presence of small amounts of BPB as an indicator reagent.