Effects of various photoradiation regimens on the antitumor efficacy of photodynamic therapy for R3230AC mammary carcinomas release_4gvs43i6xjd5jgnx3k2iiglcka

by S L Gibson, K R VanDerMeid, R S Murant, R F Raubertas, R Hilf

Published in Cancer Research.

1990   Volume 50, Issue 22, p7236-41

Abstract

Clinical photodynamic therapy consists of the systemic administration of a derivative of hematoporphyrin (Photofrin II) followed by exposure of malignant lesions to continuous visible laser irradiation. We investigated the effects of various modifications of laser light delivery on the efficacy of photodynamic therapy in controlling R3230AC mammary tumor growth. We observed a significant delay in growth (from initial to 2 times initial volume) of tumors exposed to periodic irradiation (100 mW/cm2/0.25 h, 1-h dark interval, 100 mW/cm2/0.25 h; total fluence, 180 J/cm2), compared to untreated controls or to tumors receiving continuous irradiation at the same total fluence. Other periodic light treatment regimens, consisting of 3-, 6-, or 24-hr dark intervals, delayed tumor growth but not significantly more than continuous irradiation at the same fluence. A biochemical basis was sought by comparing continuous versus periodic irradiation for effects on mitochondrial or cytosolic enzymes in vivo. Although both cytochrome c oxidase and pyruvate kinase activities were reduced dramatically during the first 24 h by continuous or periodic irradiation schemes, recovery of enzyme activity to initial levels took longer after the periodic irradiation protocol (168 h), compared to the continuous irradiation regimen (72 h). We observed a significantly greater delay in the growth of tumors exposed to 50 mW/cm2/2 h continuously, compared to controls or to tumors exposed to the same total fluence but with light delivered at 100 or 200 mW/cm2. The data presented here indicate that the efficacy of photodynamic therapy could be significantly increased by modifications in the delivery of photoradiation.
In text/plain format

Archived Files and Locations

application/pdf  1.4 MB
file_wxbsnsqktfdbfnnrqxbfhgjfue
cancerres.aacrjournals.org (web)
web.archive.org (webarchive)
Read Archived PDF
Preserved and Accessible
Type  article-journal
Stage   published
Date   1990-11-15
Language   en ?
PubMed  2171760
Container Metadata
Not in DOAJ
In Keepers Registry
ISSN-L:  0008-5472
Work Entity
access all versions, variants, and formats of this works (eg, pre-prints)
Catalog Record
Revision: 65d3acdc-4877-4f2e-86b9-bf159d3117da
API URL: JSON