title: Microendoscopy for hypericin fluorescence tumor diagnosis in a subcutaneous glioma mouse model.
abstract: BACKGROUND
  New treatment strategies for malignant gliomas are indispensible, due to the poor prognosis for patients. Fluorescence diagnosis (FD) and photodynamic therapy (PDT) are currently under intensive investigation and seem to improve the prognosis. Especially for deep seated malignant brain lesions and in order to optimize therapy new diagnostic tools are needed.
  
  
  METHODS
  In a syngeneic subcutaneous glioma mouse model we investigated the time dependent hypericin (HYP) uptake in malignant tumor tissue by microendoscopically fluorescence measurements. The HYP fluorescence in tumor was also detected by fluorescence microscopy (FM) and was compared to endoscopic data.
  
  
  RESULTS
  Both methods, microendoscopy and FM, demonstrated time dependent HYP uptake in subcutaneously implanted mouse glioma. Maximum of HYP uptake was achieved after 6h, measured with both methods. FM reached a 10-fold increase in fluorescence intensity compared to the autofluorescence. Measured by microendoscopy a 2.2-fold HYP fluorescence intensity compared to the autofluorescence was detected. Microendoscopy enables visualization of small vessels even in healthy brain tissue by intravascular HYP fluorescence.
  
  
  CONCLUSIONS
  The new developed microendoscope enables not only fluorescence based discrimination of tumor and healthy tissue, but also semiquantitative measurements of fluorescence intensities in vivo. Individual repetitive fluorescence diagnosis will become possible by this method and opens up new possibilities for determining optimal settings of light applications for PDT.
authors.affiliation: Department of Neurosurgery, University of Tübingen, Hoppe-Seyler-Str. 3, 72076 Tübingen, Germany.
authors.forename: Susan
authors.initials: S
authors.lastname: Noell
authors.forename: Guenther C
authors.initials: GC
authors.lastname: Feigl
authors.forename: Dzenan
authors.initials: D
authors.lastname: Serifi
authors.forename: Daniel
authors.initials: D
authors.lastname: Mayer
authors.forename: Ulrike
authors.initials: U
authors.lastname: Naumann
authors.forename: Werner
authors.initials: W
authors.lastname: Göbel
authors.forename: André
authors.initials: A
authors.lastname: Ehrhardt
authors.forename: Rainer
authors.initials: R
authors.lastname: Ritz
mesh_terms: D000818:Animals; D000873:Anthracenes; D001932:Brain Neoplasms / Q000378:metabolism* / Q000473:pathology*; D045744:Cell Line, Tumor; D004195:Disease Models, Animal; D004724:Endoscopy / Q000379:methods*; D005910:Glioma / Q000378:metabolism* / Q000473:pathology*; D008657:Metabolic Clearance Rate; D051379:Mice; D010569:Perylene / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D017319:Photosensitizing Agents / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012878:Skin Neoplasms / Q000378:metabolism / Q000473:pathology; D013050:Spectrometry, Fluorescence / Q000379:methods*; D014018:Tissue Distribution
chemical_list: D000873:Anthracenes; D017319:Photosensitizing Agents; D010569:Perylene; C004965:hypericin
keywords: Fluorescence visualization; Glioma; Hypericin; Microendoscope; Photodiagnosis