1,720,969 research outputs found
Fluorescence resonance energy transfer imaging as a tool for in situ evaluation of cell morphofunctional characteristics.
No full textPossibili correlazioni tra proprietà di autofluorescenza e attività funzionale del parenchima epatico di anfibi durante il ciclo annuale.
No full textDistribution of di-sulfonated aluminum phthalocyanine and Photofrin II in living cells: a comparative fluorometric study.
No full text
Human Liver Autofluorescence: An Intrinsic Tissue Parameter Discriminating Normal and Diseased Conditions
No full textAbstract: Background and Objective: Autofluorescence (AF) emission is an intrinsic parameter that can provide real-time information on morpho-functional properties of biological tissue, being strictly related with their biochemical composition and structural organization. The diagnostic potentials of AF-based techniques have been investigated on normal, fibrotic, and steatotic liver tissues, in reference to histological features as evidenced by specific histochemical stainings.
Materials and Methods: AF emission under excitation at 366 nm has been examined on cryostatic tissue sections obtained from biopsies collected during surgical operation, by means of fluorescence imaging and microspectrofluorometric techniques.
Results: NAD(P)H, collagen, and vitamin A were found to be the endogenous fluorophores characterizing normal, fibrotic, and steatotic liver tissue AF, respectively. The differences of their photo-physical properties, in terms of emission amplitude, spectral shape, and response to irradiation, give rise to modifications of overall AF signal collected from tissues that allow the liver conditions to be distinguished.
Conclusion: The study provides a valid premise for a development of AF-based optical biopsy techniques for a real-time discrimination of liver anatomo-pathological patterns
Ipocrellina B-acetato e induzione di danni fototossici a livello subcellulare
No full textIl lavoro descrive gli effetti pro-apoptotici che un trattamento con Ipocrellina B-acetato induce in cellule HeL
Fluorescence photoconversion of diaminobenzidine as a tool for detecting photosensitizing molecules at transmission electron microscopy
No full textPhotosensitizers (PSs) are chemical compounds able to
absorb light and dissipate energy through photochemical
processes producing highly unstable chemical species (i.e.,
singlet oxygen, free radicals or reactive oxygen species) that
can damage the cell structures eventually inducing cell
death. PSs may be modified by addition of suitable chemical
groups (such as acetate or phosphate) to increase their intracellular
accumulation: the photophysical and photochemical
properties of the native PSs are affected, but the modified
compounds behave as fluorogenic substrates (FSs) since
once inside the cell the added groups are removed by cellular
esterases and the native PS characteristics are restored.
In the attempt to localize photoactive molecules at transmission
electron microscopy, HeLa cells were loaded with
two different FSs, Rose Bengal acetate or Hypocrellin B
acetate, and the photophysical properties of the intracellularly
restored PS molecules were exploited to photoconvert
diaminobenzidine into an electrondense product.
By this approach we demonstrated that these FSs enter
the cells by endocytosis, being rapidly converted into the
native PSs at the cell surface. PS molecules were also found
in endosomes, lysosomes and multivescicular bodies, as well
as free in the cytosol. This ultrastructural localization of the
photoactive molecules accounts for the multiorganelle photodamage
induced by irradiation of FS-loaded cells
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