The autofluorescence of biological tissue can be exploited for the detection and diagnosis of disease but, to date, its complex nature and relatively weak signal levels have impeded its widespread application in biology and medicine. We present here a portable instrument designed for the in situ simultaneous measurement of autofluorescence emission spectra and temporal decay profiles, permitting the analysis of complex fluorescence signals. This hyperspectral fluorescence lifetime probe utilizes two ultrafast lasers operating at 355 and 440 nm that can excite autofluorescence from many different biomolecules present in skin tissue including keratin, collagen, nicotinamide adenine dinucleotide (phosphate), and flavins. The instrument incorporates an optical fiber probe to provide sample illumination and fluorescence collection over a millimeter-sized area. We present a description of the system, including spectral and temporal characterizations, and report the preliminary application of this instrument to a study of recently resected (<2 h) ex vivo skin lesions, illustrating its potential for skin cancer detection and diagnosis.

The effects of energy substrate removal and metabolic pathway block have been examined on neuronal and glial survival in organotypic slice cultures of rat hippocampus. Slice cultures resisted 24 h of exogenous energy substrate deprivation. Application of 0.5 mM α‐cyano‐4‐hydroxycinnamate (4‐CIN) for 24 h resulted in specific damage to neuronal cell layers, which could be reversed by co‐application of 5 mM lactate. Addition of 10 mM 2‐deoxyglucose in the absence of exogenous energy supply produced widespread cell death throughout the slice. This was partly reversed by co‐application of 5 mM lactate. These effects of metabolic blockade on cell survival were qualitatively similar to the effects on population spikes recorded in the CA1 cell layer following 60 min application of these agents. The data suggest that monocarboxylate trafficking from glia to neurons is an essential route for supply of energy substrates to neurons particularly when exogenous energy supply is restricted.

These studies present clear evidence that neuroprotection by selective N-type calcium channel antagonists is mediated directly through neuronal calcium channels. In contrast, the neuroprotective effects of dihydropyridines may be mediated through vascular calcium channels or indirectly through actions in other brain regions.

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