Journal of biophotonics
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Journal of biophotonics · Jul 2012
EditorialIn vivo imaging of hepatic excretory function in the rat by fluorescence microscopy.
Applying intravital fluorescence microscopy, we assessed sinusoidal delivery and biliary clearance of two different polymethine dyes. DY635, a benzopyrylium-based hemocyanine dye with shorter excitation wavelength than indocyanine green (ICG), was validated for assessment of hepatic excretory function. ⋯ In cholestasis, hepatobiliary excretion of DY635 was markedly impaired (control 3176 ± 148 pmol vs. cholestatic 1929 ± 179 pmol; p < 0.05). DY635 even enabled an analysis at high resolution suggesting 1.) hepatocyte uncoupling and 2.) failure of primarily the canalicular pole, allowing in vivo insights into molecular mechanisms of this critical facet of hepatobiliary function.
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Journal of biophotonics · Oct 2011
EditorialOxygen-dependent delayed fluorescence measured in skin after topical application of 5-aminolevulinic acid.
Mitochondrial oxygen tension can be measured in vivo by means of oxygen-dependent quenching of delayed fluorescence of protoporphyrin IX (PpIX). Here we demonstrate that delayed fluorescence is readily observed from skin in rat and man after topical application of the PpIX precursor 5-aminolevulinic acid (ALA). ⋯ The signals contain lifetime distributions and the fitting of rectangular distributions to the data appears more adequate than mono-exponential fitting. The use of topically applied ALA for delayed fluorescence lifetime measurements might pave the way for clinical use of this technique.