Figure 4.

Time-dependent recovery of sensitivity to PDT-induced LMP following washout of U18666A. (A) 1c1c7 cultures were treated with nothing (NT) or 1 µM U18666A for 24 h prior to being washed and refed with new medium lacking U18666A. Cultures were stained with filipin immediately prior to washout or 24, 48 and 96 h post medium change. (B) 1c1c7 cultures were treated with 1 µM U18666A for 24 h prior to being washed, and refed with new medium lacking U18666A. Some cultures were stained with AO either at the time of washout, or 24, 48 and 96 h post medium change. (C) A parallel set of cultures were sensitized with 33 µM NPe6 and photoirradiated prior to being stained with AO and monitored by fluorescence microscopy. Treatments are noted in the figure. (D) Some 1c1c7 cultures were treated with nothing, light only, or 33 µM NPe6 only for 1 h prior to being stained with AO. Additional cultures were loaded with NPe6 for 1 h, washed and refed, and irradiated. Cultures were stained with AO 1 h later. Treatments are noted in the figure. Results similar to those reported in panels A, B, C and D were obtained in 4, 2, 2 and 3 additional independent experiments, respectively. White bar represents 20 microns.