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The basic principle of this approach relies on microspectrofluorometric observations of upheavals in the cell's energy metabolism and cell-to-cell metabolic communication in human and mouse melanoma cells. A striking feature is the definition of a highly active nuclear energy metabolism in M8255 human melanoma cells which is characterized by an intense fluorescence response associated with NAD(P) reduction by substrates of glycolysis or the hexose monophosphate shunt. Changes are also expected in the steady state levels of reduced/oxidized NAD(P) in the nuclear, cytoplasmic and mitochondrial compartments, which are probably dependent on ATP levels and distribution (as determined by cell metabolism and eventually the presence of ATP traps). A topographic scanning of skin lesions, either under metabolic steady state conditions or in the presence of permeating substrates, can lead to the recognition of characteristic patterns associated with pigmented and nonpigmented, malignant and nonmalignant skin lesions. The method is, in a way, an extension of microscopic transillumination techniques which have led to the identification of specific patterns associated with such lesions. However, here, a new dimension is added by introduction of fluorescence evaluations. This can represent the first step in a multiparameter approach to the non-invasive in situ fluorescence scan of dermatological lesions by inclusion of: (1) fluorescence excitation and emission spectra; (2) new fluorescence probes of cytoplasmic organelles and nuclear components. Primary emphasis should be placed on the highly active nuclear energy metabolism, which can be triggered to maximum levels when the role of mitochondria as the `cells's policeman' with regard to metabolic control is suppressed by use of topically cytotoxic agents such as the `antipsoriatic' anthralin and dicarboxylic acids used in the local treatment of melanoma. Fluorescence excitation spectroscopy may be of particular advantage in studies with the new highly sensitive cyanine nucleic acid dyes and their dimers, but caution should be exerted in the use of such compounds because of cytotoxicity (e.g., limiting it to cellular studies used in the interpretation of dermatological findings). Parallel cellular and non-invasive dermatological studies will help to define the most specific set of parameters to be used in diagnostic and prognostic evaluations of skin lesions.
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