ABSTRACT

Tumor cells have frequently demonstrated high anaerobic glycolysis, leading to high lactic acid production, and loss of regulatory inhibition of glycolysis by aerobic environments. A major drawback of some experiments in vitro is the continuing presence of the photosensitizer in the medium during photoirradiation. Such a design could lead to excessive production of oxygen species or of radicals that will damage cell, or the subcellular organelle, membranes from the outside. Hematoporphyrin derivative was shown by fluorescence microscopy to localize in mitochondria in cultured cells in vitro. The notable drawbacks of the foregoing studies are the use of mitochondria isolated from normal liver, and exposure of mitochondria to light while in the presence of the added photosensitizer. There are data indicating that differences in vascular events occur depending on the photosensitizer studied, its chemical properties, and its ability to enter and remain in cells rather than in vascular spaces.