Format

Send to

Choose Destination
Int J Radiat Biol. 2000 Sep;76(9):1233-43.

Hyperfast, early cell response to ionizing radiation.

Author information

1
Unité 350 INSERM, Institut Curie-Biologie, Orsay, France.

Abstract

PURPOSE:

To determine whether the oscillatory changes of radio-sensitivity which occur within fractions of a second to a few minutes following flash irradiation correlate with an altered incidence of apoptosis, DNA strand breaks or lipid-coupled signalling.

MATERIALS AND METHODS:

Human tumor cells (SQ-20B, LoVo) or Chinese hamster V79 fibroblasts were exposed to split-dose, pulse irradiation with 3.5 MeV electrons at high dose-rate (12 or 120 Gy x s(-1)) and the effects assessed by clonogenic assays, analysis of DNA cleavage and microscopic observation.

RESULTS:

The processes underlying oscillatory radiation response were saturable, but did not correlate with an increased incidence of DNA single- or double-strand breaks or apoptosis. N-acetylcysteine and inhibitors of lipid-derived signalling also failed to alter oscillatory response. However, this response did correlate with phenotypic alterations evoking mitotic or delayed cell death. Furthermore, high dose-rate irradiation provided a lower level of instability than protracted gamma-ray irradiation.

CONCLUSIONS:

It is proposed that the early steps of DNA damage recognition and repair following priming radiation exposure bring about rapid, synchronous remodeling of chromatin, evoking enhanced chromosome damage upon re-irradiation.

PMID:
10993634
[Indexed for MEDLINE]

Supplemental Content

Loading ...
Support Center