Linked Life Data

3581062

Source:http://linkedlifedata.com/resource/pubmed/id/3581062

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
1987-7-9
pubmed:abstractText
The relationship between tumor oxygenation and the effectiveness of photodynamic therapy (PDT) was studied in vitro and in vivo using the RIF mouse tumor model. The oxygen dependence of photodynamic inactivation of RIF cells, which had been exposed to 25 mg/kg porphyrin (dihematoporphyrin ether) in vivo, isolated and illuminated in vitro, was determined. No cell kill was achieved under anoxic conditions, full effect was reached at 5% O2, and the half value of cell inactivation was found to be at 1% O2. Tumor hypoxia was assessed after in vivo gamma-irradiation of control and PDT-treated tumors by in vitro clonogenic assay of cell radiosensitivity. In vitro control experiments established that the radio-sensitivity of PDT-surviving RIF cells was identical to that of untreated control cells. RIF tumors of treatment size (80-120 mg) contained no detectable hypoxic tumor cell fraction. PDT treatment consisting of i.p. injection of 10 mg/kg dihematoporphyrin ether 24 h prior to 45 J/cm2 of 630 nm light, rendered approximately 9% of tumor cells severely hypoxic within 10 min of treatment time. An illumination period of 30 min (135 J/cm2) induced a hypoxic tumor cell fraction of 17%, which increased to 47% within 1 h posttreatment. Despite the prompt induction of tumor hypoxia during PDT light treatment, the tumors proved highly curable (81% cures) under the present treatment conditions (depilation of tumor area, 10 mg/kg dihematoporphyrin ether i.p., 135 J/cm2). Considering the reduced effectiveness of photodynamic cell kill at low oxygen concentrations, the rapid induction of tumor hypoxia by PDT itself, and the high tumor cure rate, it has to be concluded that in the RIF tumor hypoxic tumor cells are inactivated by a mechanism other than direct photodynamic cytotoxicity, and are thus not limiting to PDT tumor response.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0008-5472
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
47
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3110-4
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1987
pubmed:articleTitle
Relationship of tumor hypoxia and response to photodynamic treatment in an experimental mouse tumor.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.