Background And Objective: The clinical usefulness of 5-ALA guided detection of tumor tissue has been demonstrated for a number of malignancies. However, current techniques of intraoperative detection of protoporphyrin IX fluorescence in situ do not offer subcellular resolution. Therefore, discrimination of non-specific 5-ALA induced fluorescence remains difficult.
Materials And Methods: In this study we have used an orthotopic glioma model to analyze PpIX fluorescence in tumor tissue and normal brain by multiphoton excitation microscopy after intraperitoneal administration of 5-ALA. A DermaInspect in vivo imaging system was used for autofluorescence measurements at 750 nm excitation and detection in the green channel of a standard photomultiplier module. For detection of PpIX fluorescence at different excitation wavelengths a red sensitive version of the photomultiplier and a filter combination of short pass filters and a color glass long pass filter was used restricting the sensitivity in the red channel to a range of 580-700 nm.
Results: Multiphoton microscopy allowed a higher structural definition of tumor tissue based on the excitation of 5-ALA induced PpIX fluorescence compared to autofluorescence imaging. The high resolution of multiphoton microscopy allowed discrimination of fluorescence from the cytoplasm of tumor cells and 5-ALA induced PpIX fluorescence of normal brain parenchyma adjacent to tumor. Fluorescence lifetime imaging showed significantly longer fluorescence lifetimes of 5-ALA induced PpIX fluorescence in tumor tissue compared to normal brain. This allowed definition and visualization of the tumor/brain interface based on this parameter alone.
Conclusion: Multiphoton microscopy of 5-ALA induced PpIX fluorescence in brain tumor tissue conceptually provides a high resolution diagnostic tool, which in addition to structural information may also provide photochemical/functional information.
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http://dx.doi.org/10.1002/lsm.20623 | DOI Listing |
Anal Chem
January 2025
Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education; Chongqing Engineering Laboratory of Nanomaterials & Sensor Technologies; School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
Developing a DNA autocatalysis-oriented cascade circuit (AOCC) via reciprocal navigation of two enzyme-free hug-amplifiers might be desirable for constructing a rapid, efficient, and sensitive assay-to-treat platform. In response to a specific trigger (), seven functional DNA hairpins were designed to execute three-branched assembly (TBA) and three isotropic hybridization chain reaction (3HCR) events for operating the AOCC. This was because three new inducers were reconstructed in TBA arms to initiate 3HCR (TBA-to-3HCR) and periodic repeats were resultantly reassembled in the tandem nicks of polymeric nanowires to rapidly activate TBA in the opposite direction (3HCR-to-TBA) without steric hindrance, thereby cooperatively manipulating sustainable AOCC progress for exponential hug-amplification (1:3).
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Laboratory for Functional and Metabolic Imaging (LIFMET), Institute of Physics, Swiss Federal Institute of Technology (EPFL), Station 3, 1015 Lausanne, Switzerland.
Photobiomodulation (PBM) therapy, a therapeutic approach utilizing low-level light, has garnered significant attention for its potential to modulate various biological processes. This study aimed at optimizing and investigating the effects of PBM on angiogenesis and mitochondrial metabolic activity. In vitro experiments using human umbilical vein endothelial cells (HUVECs) and vascular smooth muscle cells (VSMCs) were performed to assess PBM's impacts on cell migration, proliferation, endogenous protoporphyrin IX production, mitochondrial membrane potential, Rhodamine 123 fluorescence lifetime, mitochondrial morphology, and oxygen consumption.
View Article and Find Full Text PDFJ Clin Monit Comput
December 2024
Department of Critical Care, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
Mitochondrial oxygen tension (MitoPO2) is a promising novel non-invasive bedside marker of circulatory shock and is associated with organ failure. The measurement of mitoPO2 requires the topical application of 5-aminolevulinc acid (ALA) to induce sufficient concentrations of the fluorescent protein protoporphyrin-IX within (epi)dermal cells. Currently, its clinical potential in guiding resuscitation therapies is limited by the long induction time prior to obtaining a reliable measurement signal.
View Article and Find Full Text PDFNeurooncol Adv
October 2024
Department of Biomedical Engineering, Linköping University, Linköping, Sweden.
Background: Brain tumor needle biopsy interventions are inflicted with nondiagnostic or biased sampling in up to 25% and hemorrhage, including asymptomatic cases, in up to 60%. To identify diagnostic tissue and sites with increased microcirculation, intraoperative optical techniques have been suggested. The aim of this study was to investigate the clinical implications of in situ optical guidance in frameless navigated tumor biopsies.
View Article and Find Full Text PDFDiagnostics (Basel)
November 2024
Department of Neurosurgery, Medical University of Vienna, 1090 Vienna, Austria.
5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PpIX) fluorescence shows high sensitivity in detecting the tumor core of high-grade gliomas (HGG) but poor sensitivity for tissue of low-grade gliomas (LGG) and the margins of HGG. The characteristic emission peak for PpIX is known to be located at 635 nm. Recently, a second emission peak was described at 620 nm wavelength in LGG and the tumor infiltration zone of HGG.
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