Hypersensitivity to very-low single radiation doses: its relationship to the adaptive response and induced radioresistance.

2.50
Hdl Handle:
http://hdl.handle.net/10541/95823
Title:
Hypersensitivity to very-low single radiation doses: its relationship to the adaptive response and induced radioresistance.
Authors:
Joiner, M C; Lambin, P; Malaise, E P; Robson, T; Arrand, J E; Skov, K A; Marples, Brian
Abstract:
There is now little doubt of the existence of radioprotective mechanisms, or stress responses, that are upregulated in response to exposure to small doses of ionizing radiation and other DNA-damaging agents. Phenomenologically, there are two ways in which these induced mechanisms operate. First, a small conditioning dose (generally below 30 cGy) may protect against a subsequent, separate, exposure to radiation that may be substantially larger than the initial dose. This has been termed the adaptive response. Second, the response to single doses may itself be dose-dependent so that small acute radiation exposures, or exposures at very low dose rates, are more effective per unit dose than larger exposures above the threshold where the induced radioprotection is triggered. This combination has been termed low-dose hypersensitivity (HRS) and induced radioresistance (IRR) as the dose increases. Both the adaptive response and HRS/IRR have been well documented in studies with yeast, bacteria, protozoa, algae, higher plant cells, insect cells, mammalian and human cells in vitro, and in studies on animal models in vivo. There is indirect evidence that the HRS/IRR phenomenon in response to single doses is a manifestation of the same underlying mechanism that determines the adaptive response in the two-dose case and that it can be triggered by high and low LET radiations as well as a variety of other stress-inducing agents such as hydrogen peroxide and chemotherapeutic agents although exact homology remains to be tested. Little is currently known about the precise nature of this underlying mechanism, but there is evidence that it operates by increasing the amount and rate of DNA repair, rather than by indirect mechanisms such as modulation of cell-cycle progression or apoptosis. Changed expression of some genes, only in response to low and not high doses, may occur within a few hours of irradiation and this would be rapid enough to explain the phenomenon of induced radioresistance although its specific molecular components have yet to be identified.
Affiliation:
Gray Laboratory, Mount Vernon Hospital, Northwood, Middlesex, UK. joiner@graylab.ac.uk
Citation:
Hypersensitivity to very-low single radiation doses: its relationship to the adaptive response and induced radioresistance. 1996, 358 (2):171-83 Mutat. Res.
Journal:
Mutation Research
Issue Date:
4-Nov-1996
URI:
http://hdl.handle.net/10541/95823
DOI:
10.1016/S0027-5107(96)00118-2
PubMed ID:
8946022
Type:
Article
Language:
en
ISSN:
0027-5107
Appears in Collections:
All Paterson Institute for Cancer Research

Full metadata record

DC FieldValue Language
dc.contributor.authorJoiner, M Cen
dc.contributor.authorLambin, Pen
dc.contributor.authorMalaise, E Pen
dc.contributor.authorRobson, Ten
dc.contributor.authorArrand, J Een
dc.contributor.authorSkov, K Aen
dc.contributor.authorMarples, Brianen
dc.date.accessioned2010-04-07T09:44:33Z-
dc.date.available2010-04-07T09:44:33Z-
dc.date.issued1996-11-04-
dc.identifier.citationHypersensitivity to very-low single radiation doses: its relationship to the adaptive response and induced radioresistance. 1996, 358 (2):171-83 Mutat. Res.en
dc.identifier.issn0027-5107-
dc.identifier.pmid8946022-
dc.identifier.doi10.1016/S0027-5107(96)00118-2-
dc.identifier.urihttp://hdl.handle.net/10541/95823-
dc.description.abstractThere is now little doubt of the existence of radioprotective mechanisms, or stress responses, that are upregulated in response to exposure to small doses of ionizing radiation and other DNA-damaging agents. Phenomenologically, there are two ways in which these induced mechanisms operate. First, a small conditioning dose (generally below 30 cGy) may protect against a subsequent, separate, exposure to radiation that may be substantially larger than the initial dose. This has been termed the adaptive response. Second, the response to single doses may itself be dose-dependent so that small acute radiation exposures, or exposures at very low dose rates, are more effective per unit dose than larger exposures above the threshold where the induced radioprotection is triggered. This combination has been termed low-dose hypersensitivity (HRS) and induced radioresistance (IRR) as the dose increases. Both the adaptive response and HRS/IRR have been well documented in studies with yeast, bacteria, protozoa, algae, higher plant cells, insect cells, mammalian and human cells in vitro, and in studies on animal models in vivo. There is indirect evidence that the HRS/IRR phenomenon in response to single doses is a manifestation of the same underlying mechanism that determines the adaptive response in the two-dose case and that it can be triggered by high and low LET radiations as well as a variety of other stress-inducing agents such as hydrogen peroxide and chemotherapeutic agents although exact homology remains to be tested. Little is currently known about the precise nature of this underlying mechanism, but there is evidence that it operates by increasing the amount and rate of DNA repair, rather than by indirect mechanisms such as modulation of cell-cycle progression or apoptosis. Changed expression of some genes, only in response to low and not high doses, may occur within a few hours of irradiation and this would be rapid enough to explain the phenomenon of induced radioresistance although its specific molecular components have yet to be identified.en
dc.language.isoenen
dc.subjectCultured Tumour Cellsen
dc.subject.meshAdaptation, Physiological-
dc.subject.meshAnimals-
dc.subject.meshCell Death-
dc.subject.meshChlamydomonas-
dc.subject.meshCricetinae-
dc.subject.meshDose-Response Relationship, Radiation-
dc.subject.meshHumans-
dc.subject.meshMammals-
dc.subject.meshRadiation Tolerance-
dc.subject.meshTumor Cells, Cultured-
dc.titleHypersensitivity to very-low single radiation doses: its relationship to the adaptive response and induced radioresistance.en
dc.typeArticleen
dc.contributor.departmentGray Laboratory, Mount Vernon Hospital, Northwood, Middlesex, UK. joiner@graylab.ac.uken
dc.identifier.journalMutation Researchen
All Items in Christie are protected by copyright, with all rights reserved, unless otherwise indicated.