Document Detail


Characterization of Photofrin photobleaching for singlet oxygen dose estimation during photodynamic therapy of MLL cells in vitro.
MedLine Citation:
PMID:  15901957     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
A singlet oxygen dose model is developed for PDT with Photofrin. The model is based on photosensitizer photobleaching kinetics, and incorporates both singlet oxygen and non-singlet oxygen mediated bleaching mechanisms. To test our model, in vitro experiments were performed in which MatLyLu (MLL) cells were incubated in Photofrin and then irradiated with 532 nm light. Photofrin fluorescence was monitored during treatment and, at selected fluence levels, cell viability was determined using a colony formation assay. Cell survival correlated well to calculated singlet oxygen dose, independent of initial Photofrin concentration or oxygenation. About 2 x 10(8) molecules of singlet oxygen per cell were required to reduce the surviving fraction by 1/e. Analysis of the photobleaching kinetics suggests that the lifetime of singlet oxygen in cells is 0.048 +/- 0.005 micros. The generation of fluorescent photoproducts was not a result of singlet oxygen reactions exclusively, and therefore did not yield additional information to aid in quantifying singlet oxygen dose.
Authors:
Jonathan S Dysart; Michael S Patterson
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, P.H.S.     Date:  2005-05-18
Journal Detail:
Title:  Physics in medicine and biology     Volume:  50     ISSN:  0031-9155     ISO Abbreviation:  Phys Med Biol     Publication Date:  2005 Jun 
Date Detail:
Created Date:  2005-05-19     Completed Date:  2005-10-14     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0401220     Medline TA:  Phys Med Biol     Country:  England    
Other Details:
Languages:  eng     Pagination:  2597-616     Citation Subset:  IM    
Affiliation:
Juravinski Cancer Centre, Physics Research, 699 Concession St., Hamilton, Ontario L8V 5C2, Canada. jon.dysart@hrcc.on.ca
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MeSH Terms
Descriptor/Qualifier:
Adenocarcinoma
Algorithms
Animals
Cell Line, Tumor
Cell Survival / radiation effects
Dihematoporphyrin Ether / pharmacokinetics*
Dose-Response Relationship, Radiation
Light
Male
Oxygen Consumption
Photobleaching*
Photochemotherapy*
Photosensitizing Agents / pharmacokinetics*
Prostatic Neoplasms
Rats
Singlet Oxygen / metabolism*
Grant Support
ID/Acronym/Agency:
P01-CA43892/CA/NCI NIH HHS
Chemical
Reg. No./Substance:
0/Photosensitizing Agents; 17778-80-2/Singlet Oxygen; 97067-70-4/Dihematoporphyrin Ether

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


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