Abstract:
:Survival of HT29 cells was measured after irradiation with single doses of X-rays (0.05-5 Gy) and neutrons (0.025-1.5 Gy), using a Dynamic Microscopic Imaging Processing Scanner (DMIPS) with which individual cells can be accurately located in tissue culture flasks, their positions recorded, and after an appropriate incubation time the recorded positions revisited to allow the scoring of survivors. The response over the X-ray dose range 2-5 Gy showed a good fit to a Linear-Quadratic (LQ) model. For X-ray doses below 1 Gy, an increased X-ray effectiveness was observed with cell survival below the high-dose LQ prediction. The value of --dose/loge (SF) for each experimental data point, plotted against dose, demonstrated clearly how X-rays are maximally effective at doses approaching zero, becoming less effective as the dose increases and with minimal effectiveness at about 0.6 Gy then becoming more effective again as the dose increases above 1.5 Gy. This phenomenon was not seen with neutrons. Neutron RBE was calculated for each X-ray data point by taking each X-ray survival value and comparing it with the common LQ fit to all the neutron data. Over the X-ray dose range 0.05-0.2 Gy, the RBE is close to 1 indicating that these very low doses of X-rays are of similar effectiveness to neutrons in killing cells. The increase in RBE with increasing dose over the range 0.05-1 Gy, and the slight decrease in RBE above 1 Gy, reflect primarily the changes in X-ray sensitivity over the whole dose range of 0.05-5 Gy. Several arguments suggest that this phenomenon could reflect an induced radioresistance so that in this system low single doses of X-rays are more effective per Gy than higher doses in reducing cell survival because only at higher doses, above a threshold, is there sufficient damage to trigger radioprotective mechanisms.
journal_name
Int J Radiat Bioljournal_title
International journal of radiation biologyauthors
Lambin P,Marples B,Fertil B,Malaise EP,Joiner MCdoi
10.1080/09553009314450831subject
Has Abstractpub_date
1993-05-01 00:00:00pages
639-50issue
5eissn
0955-3002issn
1362-3095pii
VYD09KN6W1445RPXjournal_volume
63pub_type
杂志文章abstract:PURPOSE:To study the absorptive function of rat colon following whole-body exposure to neutron irradiation, either to the same total dose with varying proportion of neutrons or to the same neutron proportion with an increasing irradiation dose. MATERIALS AND METHODS:Different proportions of neutron irradiation were pr...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/0955300021000019221
更新日期:2002-12-01 00:00:00
abstract:PURPOSE:To carry out a comparative study on potential cytogenetic fingerprints for radiation LET in human metaphase lymphocytes. MATERIALS AND METHOD:Human lymphocytes were irradiated in vitro with 3.0 Gy 60Co gamma-rays, 0.9 Gy 3H beta-rays or 0.2 Gy 2.7 Mev neutrons. Detailed chromosome aberrations were analysed by ...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553000050201073
更新日期:2000-12-01 00:00:00
abstract:PURPOSE:A meta-analysis was conducted to obtain a 'quantitative' estimate of the extent of genetic damage in mammalian somatic cells exposed to non-ionizing radiation emitted from extremely low frequency electro-magnetic fields (ELF-EMF) and to compare with that in unexposed control cells. METHODS:The methods used for...
journal_title:International journal of radiation biology
pub_type: 杂志文章,meta分析
doi:10.1080/09553000902748575
更新日期:2009-03-01 00:00:00
abstract::We used the 'comet assay' to compare the amount of radiation-induced DNA damage in three tumour cell lines (MeWo, PECA 4451 and PECA 4197) and the extent of DNA repair in two of these lines (MeWo and PECA 4197). Tumour cells were irradiated with X-rays (0.1-10 Gy), embedded in agarose on slides, lysed with sodium dode...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553009414550371
更新日期:1994-03-01 00:00:00
abstract::Purpose To study the effect of microwave (MW) irradiation and consistent action of microwaves and static magnetic field (MF) on the giant chromosomes endoreduplication in Drosophila melanogaster Meig. Materials and methods Experiments were carried out on inbred wild type Canton-S strain. Exposure to microwaves (freque...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.3109/09553002.2016.1137105
更新日期:2016-01-01 00:00:00
abstract::Transforming growth factor-beta (TGF beta 1) plays a central role in wound healing, so its perturbation by radiation may contribute to the acute and late effects seen in irradiated skin. TGF beta 1 mRNA expression was measured by PCR, in the skin of the CD1 and CBA mouse, exposed to Sr-90 beta from an 11-mm diameter s...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553009514551231
更新日期:1995-09-01 00:00:00
abstract:PURPOSE:In a previous study, we found that exposure to a 50 Hz magnetic field (MF) could activate stress-activated protein kinase (SAPK) and P38 mitogen-activated protein (MAP) kinase (P38 MAPK) in Chinese hamster lung (CHL) fibroblast cells, and simultaneous exposure to a 'noise' MF of the same intensity inhibited the...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553000801998875
更新日期:2008-05-01 00:00:00
abstract:PURPOSE:To propose an improved version of RADACK, a stochastic simulation of radiolytic attack on DNA, that takes into account the reactivity of each amino acid of a specifically bound protein with hydroxyl radicals. To apply it to the natural lactose operator-repressor complex taking advantage of recently reported str...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/0955300031000137788
更新日期:2003-06-01 00:00:00
abstract::The relationship between cellular radiosensitivity and normal-tissue response to radiotherapy in individual cancer patients has attracted increasing attention over the last few years. Recent work has suggested that a correlation exists between fibroblast sensitivity and normal-tissue reactions. We have examined the ra...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/095530096145021
更新日期:1996-09-01 00:00:00
abstract:PURPOSE:To estimate gamma-ray doses received by Hiroshima atomic bomb survivors using electron spin resonance (ESR) of tooth enamel and to compare the results with cytogenetic data. MATERIALS AND METHODS:Tooth enamel ESR was performed for 100 teeth donated from 69 Hiroshima survivors, and conventional cytogenetic exam...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/095530098141870
更新日期:1998-06-01 00:00:00
abstract::Despite the extensive utilization of radiotherapy in cancer treatments, clinicians often face challenges in achieving desired outcomes. This is because of the existence of secondary radiation effects like bystander phenomenon that influence radiation nontargeted cells and tissues. The concept of bystander effects of r...
journal_title:International journal of radiation biology
pub_type: 杂志文章,评审
doi:10.1080/09553002.2019.1547440
更新日期:2019-03-01 00:00:00
abstract::Two novel nitroimidazole-carboranes were examined for their uptake and retention in two experimental murine solid tumours and in some normal tissues, using in vivo 11B magnetic resonance spectroscopy. The compounds were injected i.p. at 0.8mmol/kg into mice bearing either the SCCVII/Ha squamous cell carcinoma or KHT s...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/095530096144798
更新日期:1996-11-01 00:00:00
abstract::Nitrous oxide reacts during irradiation to increase the yield of .OH, a radical many believe to be a major cause of lethality. Logically, one would expect N2O to be a radiation sensitizer. In some instances it is, while in others it is not. In some cases we can explain why N2O fails to sensitize; factors such as dose ...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553009114550631
更新日期:1991-03-01 00:00:00
abstract:PURPOSE:To evaluate and compare cytotoxic and mutational effects of graded doses of gamma-rays and 4He++ ions at different LET values (nominally 80 and 123 keV/microm) in V79 cells. MATERIALS AND METHODS:4He++ ion beams at 80 and 123 keV/microm were supplied by the 7 MV Van de Graaff CN accelerator of the INFN-LNL in ...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553000210146572
更新日期:2002-09-01 00:00:00
abstract:PURPOSE:The molecular basis of gene regulation in cells exposed to ionising radiation is not fully understood. Gene regulation occurs at the transcriptional and post-transcriptional levels. Recent studies have suggested that micro-RNA (miRNA) plays a significant role at the post-transcriptional gene regulation. miRNA a...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.3109/09553001003734568
更新日期:2010-07-01 00:00:00
abstract::A novel 2-nitroimidazole with a theophylline side-chain, 7-(4'-(2-nitroimidazol-1-yl)-butyl)-theophylline, (NITP) was as efficient a hypoxic-cell radiosensitizer as misonidazole. However, if cells were irradiated with NITP under hypoxic conditions and then exposed to the drug under aerobic conditions, a much larger ra...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553009214551671
更新日期:1992-06-01 00:00:00
abstract:PURPOSE:The nature of the transferrable factor which goes from irradiated objects to bystander objects remains undefined. Most agree that a chemical entity is the likely 'factor' although some authors have produced in vitro evidence for the involvement of a physical component or a very potent volatile capable of travel...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.3109/09553002.2012.698366
更新日期:2012-08-01 00:00:00
abstract::An assay system was developed to detect changes of restriction fragment profiles obtained after pulsed-field gel electrophoresis (PFGE) for DNA from mammalian cells that were irradiated and incubated for repair. DNA was prepared from irradiated log-phase human melanoma cells (MRI 221) after incubation for repair (6 h)...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/095530096144518
更新日期:1996-12-01 00:00:00
abstract:PURPOSE:Many studies have shown that exposure to radiofrequency radiation (RFR) could activate cellular signal transduction pathways. In the present research, we investigated the effects of exposure to a 1.8-GHz RFR at different intensities on epidermal growth factor (EGF) receptor clustering and phosphorylation in hum...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.3109/09553002.2011.634882
更新日期:2012-03-01 00:00:00
abstract:PURPOSE:To evaluate thiol-disulphide homeostasis - a novel, easily calculated, readily available, and relatively cheap oxidative stress marker - in radiation workers and compare the results with healthy controls. MATERIALS AND METHODS:A total of 108 participants were enrolled in the study including 63 hospital workers...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553002.2017.1304668
更新日期:2017-07-01 00:00:00
abstract:PURPOSE:Melanoma is mainly treated by surgery and rarely with radiation because of the high radioresistance of this tumor. Nevertheless, radiotherapy is the preferred treatment modality for unresectable lesions and avoiding cosmetic disfigurement caused by surgical excision. This study investigated the therapeutic adva...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553002.2017.1276309
更新日期:2017-05-01 00:00:00
abstract::Fluorescence in situ hybridization (FISH) with a combination of three composite whole chromosome-specific DNA probes for human chromosomes 1, 4 and 12 was used to analyse in vitro radiation-induced dicentrics and symmetrical translocations in peripheral lymphocytes. Translocations could be rapidly and efficiently dete...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553009214552621
更新日期:1992-12-01 00:00:00
abstract::An iodinated DNA ligand, iodo Hoechst 33258, which binds in the minor groove of DNA, enhances DNA strand breakage and cell killing by UV-A irradiation. The sites of UV-induced strand breaks reflect the known sequence specificity of the ligand. ...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553009014551061
更新日期:1990-05-01 00:00:00
abstract::A new approach is reported that combines synchrotron radiolysis and mass spectrometry to probe the structure of proteins. Hydroxyl radicals produced upon the radiolysis of protein solutions using synchrotron light modify amino acid side-chains on millisecond timescales. This results in the formation of stable oxidatio...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553000110094805
更新日期:2002-02-01 00:00:00
abstract:PURPOSE:One of the most important issues regarding radiofrequency electromagnetic fields (RF-EMF) is their effect on genetic material. Therefore, we investigated the cytogenotoxic effects of 900 MHz radiofrequency electromagnetic fields (RF-EMF) and the effect of a recovery period after exposure to RF-EMF on bone marro...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.3109/09553002.2013.809170
更新日期:2013-11-01 00:00:00
abstract::Free radical formation in aqueous solutions of ubiquinone (coenzyme Qo) induced by ultrasound was studied by EPR and spin trapping with 3,5-dibromo-4-nitrosobenzene sulphonate. When aqueous solutions of ubiquinone were sonicated with 50-kHz ultrasound in the presence of argon or nitrogen, radicals formed by addition o...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/095530096146246
更新日期:1996-01-01 00:00:00
abstract::High doses of rHIL-1 protected C3H/HeN mice against lethal radiation damage. The optimum time of radioprotection was found when this cytokine was administered at 4 h and at 20 h before irradiation. The dose reduction factors when the IL-1 was administered at those times were about 1.30. The radioprotection at the opti...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553008914551621
更新日期:1989-10-01 00:00:00
abstract::Induction by gamma-radiation, UV radiation or hydroxyurea of RecA gene product synthesis in Escherichia coli, monitored as beta-D-galactosidase in recA-lacZ fusion strains, was shown to be inhibited if 2-mercaptoethylamine (MEA) was added before treatment with the inducing agents. If cysteine (Cys) at low concentratio...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/095530096146228
更新日期:1996-01-01 00:00:00
abstract::Skin fibroblasts from ataxia telangiectasia (AT) patients, obligate AT heterozygotes (ATH) and normal individuals were studied for colony-forming ability and repair of DNA double-strand breaks (dsb) after gamma-irradiation. AT cells were three to four times more radiosensitive than normal cells at high and low dose-ra...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553009114552601
更新日期:1991-11-01 00:00:00
abstract:PURPOSE:The assessment of biological effects caused by radiation exposure has been currently carried out with the linear-quadratic (LQ) model as an extension of the linear non-threshold (LNT) model. In this study, we suggest a new mathematical model named as SeaSaw (SS) model, which describes proliferation and cell dea...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553002.2021.1854487
更新日期:2020-12-15 00:00:00