Document Detail


Simple photodynamic therapy dose models fail to predict the survival of MLL cells after HPPH-PDT in vitro.
MedLine Citation:
PMID:  19140895     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Fluorescence photobleaching, photodynamic therapy (PDT) oxygen consumption and clonogenic cell survival were investigated during 2-(1-hexyloxethyl)-2-devinyl pyropheophoribde-a (HPPH) PDT of MAT-LyLu cells in vitro. Cells were incubated with HPPH concentrations of 0.24, 1.2, 3.6 or 12 microm for 4 h and then treated with 650 nm light under oxygenated and hypoxic conditions. Fluorescence spectra were acquired during treatment and photobleaching was quantified using singular value decomposition of the spectra. Cell survival was measured at set times during the treatment using a colony forming assay. Intracellular fluorescence lifetime measurements were also performed at each incubation concentration. The photobleaching kinetics did not follow first- or second-order kinetics and the fluorescence lifetime was similar for all intracellular concentrations. As the intracellular concentration of drug was increased, the amount of singlet oxygen and the absorbed quanta per cell required to achieve the same cell kill increased. Singlet oxygen dose was calculated using one- and two-compartment models of HPPH intracellular distribution. It was found that a two-compartment model, in which a PDT-sensitive binding site saturates at low concentrations, accounts for the observed photobleaching, oxygen consumption and cell survival.
Authors:
Mark A Weston; Michael S Patterson
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2008-12-18
Journal Detail:
Title:  Photochemistry and photobiology     Volume:  85     ISSN:  0031-8655     ISO Abbreviation:  Photochem. Photobiol.     Publication Date:    2009 May-Jun
Date Detail:
Created Date:  2009-05-12     Completed Date:  2009-06-26     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0376425     Medline TA:  Photochem Photobiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  750-9     Citation Subset:  IM    
Affiliation:
Juravinski Cancer Centre, Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON, Canada. mark.weston@jcc.hhsc.ca
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MeSH Terms
Descriptor/Qualifier:
Animals
Cell Line, Tumor
Cell Survival
Chlorophyll / analogs & derivatives*,  therapeutic use
Dose-Response Relationship, Drug
Kinetics
Photochemotherapy*
Rats
Spectrometry, Fluorescence
Grant Support
ID/Acronym/Agency:
P01-CA43892/CA/NCI NIH HHS
Chemical
Reg. No./Substance:
1406-65-1/Chlorophyll; 149402-51-7/2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-a

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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