Translator Disclaimer
1 April 2001 Bystander Effects in Cell Death Induced by Photodynamic Treatment, UVA Radiation and Inhibitors of ATP Synthesis
Author Affiliations +

Confluent layers of MDCK II cells were treated with four different photosensitizers (a purified version of hematoporphyrin derivative [Photofrin], tetra(3-hydroxyphenyl)porphine [3-THPP], meso-tetra(4-sulphonatophenyl)porphine [TPPS4] and ALA-induced Protoporphyrin IX) and irradiated with blue light, with UVA without exogenous photosensitizers, or incubated with the metabolic inhibitors carbonyl cyanide m-chlorophenylhydrazone and 2-deoxy-d-glucose. Necrotic and apoptotic cells were detected about 4 h later by fluorescence microscopy. Dead cells appeared in distinct clusters in the confluent layers. The number of dead cells in these clusters was determined by manual counting and image analysis. Forty-one of the 43 experimental distributions of dead cells in clusters were found to be significantly different from a Monte Carlo simulation of the distribution of independently inactivated cells. However, a Monte Carlo simulation model, assuming that each dead cell increased the probability of inactivation of adjacent cells, fitted 34 of the 43 observed distributions of dead cells in clusters, indicating a significant bystander effect for all the investigated treatments. The bystander-effect model parameter, defined as a cell's increase in probability of dying when it has dead neighbors, was significantly lower for 3-THPP-PDT and TPPS4-PDT than for Photofrin-PDT, ALA-PDT and treatment with metabolic inhibitors.

Jostein Dahle, Even Angell-Petersen, Harald B. Steen, and Johan Moan "Bystander Effects in Cell Death Induced by Photodynamic Treatment, UVA Radiation and Inhibitors of ATP Synthesis," Photochemistry and Photobiology 73(4), 378-387, (1 April 2001).<0378:BEICDI>2.0.CO;2
Received: 7 December 2000; Accepted: 1 January 2001; Published: 1 April 2001

This article is only available to subscribers.
It is not available for individual sale.

Get copyright permission
Back to Top