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22 May 1995 Tissue fluorescence changes and protein coagulation after Nd:YAG interstitial laser photocoagulation
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In attempting to identify a tissue response suitable for monitoring interstitial laser photocoagulation (ILP) during treatment, we observed that the lesions produced in tissue by interstitial irradiation with the 1064 nm radiant energy produced by an Nd:YAG laser fluoresce when exposed to the long-wave ultraviolet light produced by a handheld UV fluorescent lamp. The visual extent of the fluorescence was correlated to the irradiation time and energy fluence rate. Fluorescence spectra of four tissue chromophores, serum albumin, Type 1 collagen, nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) exhibited similar spectra to the fluorescence of solubilized tissue. No significant changes in the fluorescent spectra were observed upon heating to 70°C for 5 minutes the chromophores or tissue sample prior to solubilization. In another experiment, the tissue was thermally damaged by immersion in phosphate buffered saline from 60-100°C for 30-90 seconds. The reflectance from 400-800 nm of the intact tissue was noted to increase with increasing thermal damage up to 80°C, and the decrease at 90°C and 100°C. Activation energies calculated from this data was suggestive of thermal damage to blood and other tissue constituents. In order to see if changes in electrophoretic mobility occurred upon heating, nondenaturing polyacrylamide gel electrophoresis (native PAGE) was done on heated that were solubilized by ultrasonication. The gels showed a quantitative loss of tissue proteins with increasing thermal damage, and the irreversible formation of heavy protein coagulums.
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Stephen Thomas Flock, Scott Ferguson, Lewis Krain M.D., Patric N. Anderson, Tharesh Udupa, and Scott J. Stern M.D. "Tissue fluorescence changes and protein coagulation after Nd:YAG interstitial laser photocoagulation", Proc. SPIE 2391, Laser-Tissue Interaction VI, (22 May 1995);

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