Linked Life Data

9613242

Source:http://linkedlifedata.com/resource/pubmed/id/9613242

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1998-6-24
pubmed:abstractText
The photobleaching of meta-tetra(hydroxyphenyl)chlorin (mTHPC) (irradiation wavelength 413 nm) in protein-containing solution was evaluated by decay in absorbance in Soret band and in fluorescence (lambda exc = 423 nm, lambda em = 655 nm). Light exposure resulted in a decrease in absorption throughout the spectrum and simultaneous appearance of new absorption bands in the spectral region 325-450 nm. The rate of mTHPC photodegradation, followed by decay in absorbance, was 15-fold lower than that observed in fluorescence. This fact reflects the photobleaching of presumably monomeric, fluorescing species of mTHPC. In order to determine the consequences of photobleaching of fluorescing mTHPC material on cellular uptake and photocytotoxicity, human HT29 colon adenocarcinoma cells were incubated with photobleached mTHPC during 5 h with or without following irradiation with the fixed fluence. Surprisingly, but up to the time when the fluorescence decreased by 50%, only a slight decrease in photocytotoxicity was detected. Either aggregated forms that have been taken up undergo intracellular monomerization (but we did not observe increase in fluorescence in living cells) or the photodynamic activity is mostly due to aggregates. The discrepancy of mTHPC-photodynamic therapy (PDT) effect and fluorescence measurements may suggest that aggregated mTHPC plays an important role in mTHPC-PDT.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0031-8655
pubmed:author
pubmed:issnType
Print
pubmed:volume
67
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
584-90
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Characterization of photodegradation of meta-tetra(hydroxyphenyl)chlorin (mTHPC) in solution: biological consequences in human tumor cells.
pubmed:affiliation
Unité de Recherche en Thérapie Photodynamique, Centre Alexis Vautrin, Vandoeuvre-les-Nancy, France.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't