1,720,972 research outputs found
Multiphoton microscopy and fluorescence lifetime imaging of brain and brain tumor tissue
No full textDNA topology-modulating agent chloroquine activates p53-dependent transcriptional response and induces apoptosis in glioma cells
No full textDNA topology-modulating agent chloroquine activates p53-dependent transcriptional response and induces apoptosis in glioma cells
No full textMultiphoton excitation fluorescence microscopy of 5-aminolevulinic acid induced fluorescence in experimental gliomas
No full textBackground 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 PpTX 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
Activation of the p53 transcriptional response by chloroquine in glioma cells: Unknown side of the known drug
No full textMultiphoton microscopy and fluorescence lifetime imaging of brain and brain tumor tissue
No full textActivation of the p53 transcriptional response by chloroquine in glioma cells: Unknown side of the known drug
No full textStructural and photochemical imaging of brain tumor tissue by time-resolved multiphoton excitation microscopy
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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