Fluorescence digital microscopy of interstitial macromolecular diffusion in burn injury

Computer vision techniques implemented on an IBM PC/AT have been applied to the study of microvascular permeability and interstitial diffusion in dorsal skin flap chamber preparations of hamsters. Experimental data was obtained for the leakage of fluorescent labelled dextran (70,000 daltons) after a precisely controlled mild degree of localized thermal trauma and compared with control data acquired prior to burn injury. Computer vision analysis techniques were applied to convert the fluorescent images into two-dimensional concentration maps. Interstitial diffusion coefficient values were computed from measured extravascular concentration profiles around a vessel of interest, assuming cylindrical or rectangular geometry, and optimally fitting a diffusion model to the data. An increase in the apparent diffusivity after mild thermal trauma was observed. Novel techniques were applied to solve hardware problems related to data acquisition and analysis, and a new library of software was developed to handle specific image processing requirements.