Abstract:
:In an attempt to elucidate mechanisms underlying the variation in radiosensitivity during the cell cycle, mutations in the HPRT gene were selected with 6-thioguanine, quantified and characterized in synchronous human bladder carcinoma cells (EJ30-15) that were irradiated in G1 or S phase with 3 or 6 Gy. Synchronous cells were obtained by mitotic selection, with approximately 98% of the cells in G1 phase when they were irradiated after 3 h of incubation, and 75% in S phase when they were irradiated after 14 h of incubation. The mutant frequencies were approximately 4-fold higher (P < 0.01) when cells were irradiated in G1 phase compared with S phase, and the lowest frequency (1.5 x 10(-5) for 3 Gy during S phase) was approximately 10-fold higher than the spontaneous frequency. Exon analysis by multiplex polymerase chain reaction was performed on DNA isolated from each independent mutant. The different types of mutants were categorized as class 1, which consisted of base-pair changes or small deletions less than 20 bp; class 2, which consisted of deletions greater than 20 bp but with one or more HPRT exons present; and class 3, which consisted of deletions encompassing the entire HPRT gene and usually genomic markers located 350-750 kbp from the 5' end of the gene and/or 300-1400 kbp from the 3' end. A "hotspot" for class 2 deletions was observed between exons 6 and 9 (P < 0.01). For cells irradiated during G1 phase, the percentages for the different classes (total of 78 mutants) were similar for 3 and 6 Gy, with a selective induction of class 3 mutants (34-38%) compared with spontaneous mutants (3%, total 20). When S-phase cells were irradiated with 3 Gy, there were fewer class 1 mutants (21%, total 37) than when cells were irradiated in G1 phase with 3 Gy (45%, total 42) (P < 0.01). The greatest change was observed when the dose was increased in S phase from 3 Gy to 6 Gy (total of 43 mutants), with the frequency of class 2 mutants decreasing dramatically from 30% to 1% (P < 0.005). A similar decrease in class 2 mutants with an increase in dose has been observed by others in asynchronous cultures of normal human fibroblasts. We hypothesize that these differences occur because: (a) there is more error-free repair of double-strand breaks (DSBs) during S than G1 phase; (b) a single DSB within the HPRT gene causes a class 2 mutation or a certain percentage of class 1 mutations, while two DSBs, with one in each approximately 1-Mbp region 5' and 3' of the gene, cause a class 3 mutation; and (c) a repair process that is induced when the dose during S phase is increased from 3 to 6 Gy results in a preferential decrease in class 2 mutations.
journal_name
Radiat Resjournal_title
Radiation researchauthors
Leonhardt EA,Trinh M,Forrester HB,Johnson RT,Dewey WCsubject
Has Abstractpub_date
1997-12-01 00:00:00pages
548-60issue
6eissn
0033-7587issn
1938-5404journal_volume
148pub_type
杂志文章abstract::This laboratory previously demonstrated that hyperbaric oxygen and hyperbaric carbogen improved oxygenation in the R3230Ac tumor, but normobaric 100% O2 and carbogen did not. The current study assessed tumor growth after exposure to radiation plus either hyperbaric oxygen, carbogen or carbogen/nicotinamide and the rel...
journal_title:Radiation research
pub_type: 杂志文章
doi:
更新日期:1997-06-01 00:00:00
abstract::The hyperthermic inhibition of cellular DNA synthesis, i.e., reduction in replicon initiation and delay in DNA chain elongation, was previously postulated to be involved in the induction of chromosomal aberrations believed to be largely responsible for killing S-phase cells. Utilizing asynchronous Chinese hamster ovar...
journal_title:Radiation research
pub_type: 杂志文章
doi:
更新日期:1988-04-01 00:00:00
abstract::The effect of X irradiation on the respiration of rat thymocytes was studied. An increase in the rate of O2 uptake was observed 1 h after cells were irradiated with doses of 6-10 Gy. The radiation-induced increase in respiration could be blocked by oligomycin, an inhibitor of mitochondrial ATP synthase, suggesting con...
journal_title:Radiation research
pub_type: 杂志文章
doi:
更新日期:1994-04-01 00:00:00
abstract::Normal human fibroblasts in plateau phase ( congruent with 95% G(1) phase) were stained with the vital nuclear dye Hoechst 33342 (blue fluorescence) or the vital cytoplasmic dye Cell Tracker Orange (orange fluorescence) and plated at a ratio of 1:1. Only the blue-fluorescing nuclei were microbeam-irradiated with a def...
journal_title:Radiation research
pub_type: 杂志文章
doi:10.1667/rr3236
更新日期:2004-10-01 00:00:00
abstract::Experimental measurements of the radial restricted linear energy transfer (LETr) for alpha beams of 18.3 MeV/n in tissue-equivalent gas were presented. The radial dose distribution for the alpha beam was deduced from the restricted LET measurements. A differential W value for the alpha particle in the tissue-equivalen...
journal_title:Radiation research
pub_type: 杂志文章
doi:
更新日期:1987-12-01 00:00:00
abstract::Polonium-210 is a naturally occurring radioactive element that decays by emitting an alpha particle. It is in the air we breathe and also a component of tobacco smoke. Polonium-210 is used as an anti-static device in printing presses and gained widespread notoriety in 2006 after the poisoning and subsequent death of a...
journal_title:Radiation research
pub_type: 杂志文章
doi:10.1667/RR13395.1
更新日期:2014-02-01 00:00:00
abstract::Using an electron storage ring as a source of radiation, the wavelength dependence of inactivation and membrane damage in yeast cells (Saccharomyces cerevisiae) was investigated in the range from 145 to 254 nm, with special reference to the effects of vacuum-uv radiation. The cells were irradiated on a Millipore filte...
journal_title:Radiation research
pub_type: 杂志文章
doi:
更新日期:1983-12-01 00:00:00
abstract::Octacalcium phosphate (OCP) {Ca8H2(PO4)6×5H2O] has attracted increasing attention over the last decade as a transient intermediate to the biogenic apatite for bone engineering and in studies involving the processes of pathological calcification. In this work, OCP powders obtained by hydrolysis of dicalcium phosphate d...
journal_title:Radiation research
pub_type: 杂志文章
doi:10.1667/RADE-20-00194.1
更新日期:2020-12-10 00:00:00
abstract::We have tested chronic exposure to 90Y beta radiation for its action as a complete tumor promoter, a stage I tumor promoter, or a stage II tumor promoter in SENCAR mouse skin. In skin initiated with a single application of 7,12,dimethylbenz[a]anthracene (DMBA, 10 nmol), chronic exposure to beta radiation as a complete...
journal_title:Radiation research
pub_type: 杂志文章
doi:
更新日期:1992-02-01 00:00:00
abstract::Results from several laboratories, including ours, have suggested that measurements of radiation-induced DNA strand breaks and DNA-protein crosslinks (DPCs) may be used to estimate the hypoxic fraction or fractional hypoxic volume of tumors and normal tissues. This suggestion has been predicted on both published and u...
journal_title:Radiation research
pub_type: 杂志文章
doi:
更新日期:1995-05-01 00:00:00
abstract::Vascular injury after radiation exposure contributes to multiple types of tissue injury through a cascade of events. Some of the earliest consequences of radiation damage include increased vascular permeability and promotion of inflammation, which is partially manifested by increased leukocyte-endothelial (L/E) intera...
journal_title:Radiation research
pub_type: 杂志文章
doi:10.1667/RR14896.1
更新日期:2018-07-01 00:00:00
abstract::Determinations of the LET distribution, phi(L), of charged particles within a spacecraft in low-Earth orbit have been made. One method used a cylindrical tissue-equivalent proportional counter (TEPC), with the assumption that for each measured event, lineal energy, y, is equal to LET and thus phi(L) = phi(y). The othe...
journal_title:Radiation research
pub_type: 杂志文章
doi:10.1667/0033-7587(2001)156[0310:coldmi]2.0.co;2
更新日期:2001-09-01 00:00:00
abstract::Topical applications of MEA (beta-mercaptoethylamine or cysteamine), WR-2721 [S-2-(3-aminopropylamino)-ethylphosphorothioic acid], and N-acetylcysteine (NAC) were tested for their ability to protect the normal skin of the hind legs of mice against acute and late damage from single doses of 137Cs radiation. No signific...
journal_title:Radiation research
pub_type: 杂志文章
doi:
更新日期:1983-01-01 00:00:00
abstract::Although tissue mast cells are derived from the bone marrow, some descendants of bone marrow-derived precursors retain the ability to proliferate and differentiate into mast cells even after localization in the skin. The purpose of the present study was to determine the D0 values for mast-cell precursors in the bone m...
journal_title:Radiation research
pub_type: 杂志文章
doi:
更新日期:1983-01-01 00:00:00
abstract::Plateau-phase A549 cells exhibit a high capacity for repair of potentially lethal radiation damage (PLD). Previously it was found that PLD repair could be partially inhibited by increasing the extracellular pH (pHe) of the spent medium from its normal value of 6.7-6.8 to 7.6 during postirradiation holding. The present...
journal_title:Radiation research
pub_type: 杂志文章
doi:
更新日期:1994-08-01 00:00:00
abstract::Comparatively high exposures to power-frequency electric and magnetic fields produce established biological effects that are explained by accepted mechanisms and that form the basis of exposure guidelines. Lower exposures to magnetic fields (< 1 microT average in the home) are classified as "possibly carcinogenic" on ...
journal_title:Radiation research
pub_type: 杂志文章
doi:10.1667/rr3522.1
更新日期:2006-04-01 00:00:00
abstract::Electron microbeam experiments are planned or under way to explore in part the question regarding whether the bystander effect is a general phenomenon or is restricted to high-LET radiation. Since low-LET radiations scatter more readily compared to high-LET radiations, identifying bystander cells and assessing the pot...
journal_title:Radiation research
pub_type: 杂志文章
doi:10.1667/0033-7587(2001)155[0089:moakem]2.0.co;2
更新日期:2001-01-01 00:00:00
abstract::Neurons are essential components of neural circuits and provide brain function organization. We previously reported that X irradiation induces apoptosis in immature neurons. To the best of our knowledge, there have been few reports investigating the effects of X irradiation on mature neurons. We analyzed the effects o...
journal_title:Radiation research
pub_type: 杂志文章
doi:10.1667/RR3098.1
更新日期:2013-06-01 00:00:00
abstract::We have previously published the techniques and preliminary results of an SV40 viral probe assay for gamma-radiation-induced single- and double-strand DNA breaks and their intracellular repair in higher cells (Radiat. Res. 101, 356-372, 1985). Those experiments with SV40 infected CV-1 monkey kidney cells suggested tha...
journal_title:Radiation research
pub_type: 杂志文章
doi:
更新日期:1988-12-01 00:00:00
abstract::Exposure to ionizing radiation or a variety of chemical agents is known to increase the risk of developing malignancy and many tumors have been linked to inflammatory processes. In most studies, the potentially harmful effects of ionizing radiation or other agents are considered in isolation, mainly due to the large n...
journal_title:Radiation research
pub_type: 杂志文章
doi:10.1667/rr2690.1
更新日期:2012-05-01 00:00:00
abstract::Here we report that suramin sensitizes LM217, MDA-MB-468, T98G and A431 cells to ionizing radiation. Suramin sensitized cells to X radiation in a dose-dependent fashion, and longer exposure to suramin before X irradiation resulted in more efficient sensitization. The dose-modifying factors calculated from the survival...
journal_title:Radiation research
pub_type: 杂志文章
doi:10.1667/rr3217
更新日期:2004-09-01 00:00:00
abstract::This work provides a description of a new interaction, cross-section-based model for radiation-induced cellular inactivation, sublethal damage, DNA repair and cell survival, with the ability to more accurately elucidate different radiation-response phenomena. The principal goal of this work is to describe the damage-i...
journal_title:Radiation research
pub_type: 杂志文章
doi:10.1667/RADE-20-00052.1
更新日期:2020-09-16 00:00:00
abstract::There has been ongoing debate and discussion concerning whether the funding source influenced the outcome of research on human health effects from exposure to radiofrequency fields (RF, electromagnetic waves that carry energy as they propagate in air and dense media). In a study of 225 publications, in which we sought...
journal_title:Radiation research
pub_type: 杂志文章
doi:10.1667/RR15364.1
更新日期:2019-10-01 00:00:00
abstract::Gleevec, a selective tyrosine kinase inhibitor, retarded the growth of anaplastic thyroid cancer cell lines in vitro and in vivo through selective inhibition of ABL tyrosine kinase activity. In the present study, we investigated the ability of Gleevec to modulate the in vitro and in vivo radiation response of anaplast...
journal_title:Radiation research
pub_type: 杂志文章
doi:10.1667/rr3466.1
更新日期:2006-01-01 00:00:00
abstract::A biphasic curve was observed when surviving allogeneic lytic activity was plotted as a function of irradiation delivered before sensitization. Flow cytometry analysis demonstrated that the number of cells was reduced in response to increasing dose and that subset precursors Lyt 1+2+ were proportionally more radiosens...
journal_title:Radiation research
pub_type: 杂志文章
doi:
更新日期:1984-11-01 00:00:00
abstract::It is well established that high-LET radiations efficiently induce chromosome aberrations. However, data on the effect of protons on telomere maintenance, as involved in genomic stability, are scarce and contradictory. Here we demonstrate that high-LET protons induce telomere lengthening in human primary fibroblasts a...
journal_title:Radiation research
pub_type: 杂志文章
doi:10.1667/RR2127.1
更新日期:2010-11-01 00:00:00
abstract::Cellular nonprotein thiols (NPSH) consist of glutathione (GSH) and other low molecular weight species such as cysteine, cysteamine, and coenzyme A. GSH is usually less than the total cellular NPSH, and with thiol reactive agents, such as diethyl maleate (DEM), its rate of depletion is in part dependent upon the cellul...
journal_title:Radiation research
pub_type: 杂志文章
doi:
更新日期:1983-09-01 00:00:00
abstract::The detection of (41)Ca atoms in tooth enamel using accelerator mass spectrometry is suggested as a method capable of reconstructing thermal neutron exposures from atomic bomb survivors in Hiroshima and Nagasaki. In general, (41)Ca atoms are produced via thermal neutron capture by stable (40)Ca. Thus any (41)Ca atoms ...
journal_title:Radiation research
pub_type: 杂志文章
doi:10.1667/RR2043.1
更新日期:2010-08-01 00:00:00
abstract::The nitroxide Tempol, a stable free radical, has recently been shown to protect mammalian cells against several forms of oxidative stress including radiation-induced cytotoxicity. To extend this observation, six additional water-soluble nitroxides with different structural features were evaluated for potential radiopr...
journal_title:Radiation research
pub_type: 杂志文章
doi:
更新日期:1992-10-01 00:00:00
abstract::Therapeutic gain factors (TGFs) have been determined for three spontaneous tumors of the C3H mouse treated by photons + normobaric oxygen (O2(1) ATA), photons + hyperbaric oxygen (O2 3 ATA), photons + misonidazole, or fast neutrons. The tumors were early generation isotransplants of spontaneous tumors: MCaIV, a mammar...
journal_title:Radiation research
pub_type: 杂志文章
doi:
更新日期:1988-12-01 00:00:00