Browsing by Author "Georges, Joseph"

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    Acridine Orange as a Novel Photosensitizer for Photodynamic Therapy in Glioblastoma
    (Elsevier, 2018) Osman, Hany; Elsahy, Deena; Saadatzadeh, M. Reza; Pollok, Karen E.; Yocom, Steven; Hattab, Eyas; Georges, Joseph; Cohen-Gadol, Aaron A.; Neurological Surgery, School of Medicine
    Object Photodynamic therapy is an exciting treatment modality that combines the effects of a chemical agent with the physical energy from light or radiation to result in lysis of cells of interest. Acridine orange is a molecule with fluorescence properties that was demonstrated to possess photosensitizing properties. The objective of this study was to investigate the photodynamic effect of acridine orange on glioblastoma cell viability and growth. Methods Glioblastoma cells (n = 8000 cells/well at 0 hours) were exposed to acridine orange followed by white unfiltered light-emitting diodes (LED) light. Cultures were exposed to either 10 or 30 minutes of light. The cell number per well was determined at 0, 24, 48, and 72 hours after exposure. Results A dramatic cytocidal effect of acridine orange after exposure to as little as 10 minutes of white light was observed. There was almost complete eradication of the glioblastoma cells over a 72-hour period. Although acridine orange or light alone exhibited some effect on cell growth, it was not as pronounced as the combination of acridine orange and light. Conclusions This is the first study to demonstrate the photodynamic effect of acridine orange in glioblastoma cells. This data supports the need for further studies to characterize and evaluate whether this striking cytotoxic effect can be achieved in vivo. The combination of acridine orange and exposure to white unfiltered LED light may have potential future applications in management of glioblastoma.
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    In Vivo Microscopy in Neurosurgical Oncology
    (Elsevier, 2018) Osman, Hany; Georges, Joseph; Elsahy, Deena; Hattab, Eyas; Yocom, Steven; Cohen-Gadol, Aaron A.; Neurological Surgery, School of Medicine
    Intraoperative neurosurgical histopathologic diagnoses rely on evaluation of rapid tissue preparations such as frozen sections and smears with conventional light microscopy. Though useful, these techniques are time consuming and therefore unable to provide real-time intraoperative feedback. In vivo molecular imaging techniques are emerging as novel methods for generating real-time diagnostic histopathologic images of tumors and their surrounding tissues. These imaging techniques rely on contrast generated by exogenous fluorescent dyes, autofluorescence of endogenous molecules, fluorescence decay of excited molecules, or light scattering. Large molecular imaging instruments are being miniaturized for clinical in vivo use. This review discusses pertinent imaging systems that have been developed for neurosurgical use and imaging techniques currently under NADPH development for neurosurgical molecular imaging.
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    Neurosurgical Flexible Probe Microscopy with Enhanced Architectural and Cytological Detail
    (Elsevier, 2019-08) Osman, Hany; Elsahy, Deena; Slivova, Veronika; Thompson, Corey; Georges, Joseph; Yocom, Steven; Cohen-Gadol, Aaron A.; Neurological Surgery, School of Medicine
    Background Microscopic delineation and clearance of tumor cells at neurosurgical excision margins potentially reduce tumor recurrence and increase patient survival. Probe-based in vivo fluorescence microscopy technologies are promising for neurosurgical in vivo microscopy. Objective We sought to demonstrate a flexible fiberoptic epifluorescence microscope capable of enhanced architectural and cytological imaging for in vivo microscopy during neurosurgical procedures. Methods Eighteen specimens were procured from neurosurgical procedures. These specimens were stained with acridine orange and imaged with a 3-dimensional (3D)-printed epifluorescent microscope that incorporates a flexible fiberoptic probe. Still images and video sequence frames were processed using frame alignment, signal projection, and pseudo-coloring, resulting in resolution enhancement and an increased field of view. Results Images produced displayed good nuclear contrast and architectural detail. Grade 1 meningiomas demonstrated 3D chords and whorls. Low-grade meningothelial nuclei showed streaming and displayed regularity in size, shape, and distribution. Oligodendrogliomas showed regular round nuclei and a variably staining background. Glioblastomas showed high degrees of nuclear pleomorphism and disarray. Mitoses, vascular proliferation, and necrosis were evident. Conclusions We demonstrate the utility of a 3D-printed, flexible probe microscope for high-resolution microscopic imaging with increased architectural detail. Enhanced in vivo imaging using this device may improve our ability to detect and decrease microscopic tumor burden at excision margins during neurosurgical procedures.