Abstract：
:Chinese hamster V79 cells grown for several hours in suspension culture form spheroids which are more resistant to killing by ionizing radiation than cells grown on petri dishes, a phenomenon known as the "contact effect." Previous results using the alkali-unwinding assay as a measure of DNA damage have implicated differences in DNA conformation as contributing to this effect; spheroid DNA denatures more slowly in dilute alkali than monolayer DNA, perhaps due to the presence of constraints to DNA unwinding. In this paper, the rate of development of radiation resistance is shown to be similar when either cell survival or DNA unwinding is used as an end point. At the midpoint for development of resistance, approximately 10 h, the unwinding kinetics indicate that either half of the cells contain constraints to DNA unwinding, or half of the DNA in all of the cells contains constraints. The latter explanation appears more likely since all cells seem to develop these constraints at the same rate, regardless of position in the cell cycle or the degree of contact with other cells. Results using the microelectrophoresis assay to measure damage to individual nuclei confirm the fact that 10-h cultures show a homogeneous radiation response intermediate between that of monolayers and spheroids. Incubation of cells at room temperature or in the presence of drugs which inhibit cell cycle progression prevents full development of the contact effect. Conversely, incubation of cells in medium containing inhibitors of polyamine synthesis, adenylcyclase, glutathione synthesis, poly(ADP-ribose)polymerase, topoisomerase II, or cell-cell communication does not inhibit development of the contact effect as measured by DNA-unwinding kinetics.
journal_name
Radiat Resjournal_title
Radiation researchauthors
Olive PLsubject
Has Abstractpub_date
1989-01-01 00:00:00pages
79-92issue
1eissn
0033-7587issn
1938-5404journal_volume
117pub_type
杂志文章abstract：:The mortality experience between 1956 and 1985 of 8977 males employed by Atomic Energy of Canada Limited is reported. A total of 4260 men, 47% of the cohort, were exposed to low doses of external ionizing radiation at low dose rates, with a mean cumulative equivalent dose of 52.1 mSv. For cancers as a whole the excess...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1993-03-01 00:00:00
abstract：:The efficiency of boron neutron capture therapy (BNCT) for malignant gliomas depends on the selective and absolute accumulation of (10)B atoms in tumor tissues. Only two boron compounds, BPA and BSH, currently can be used clinically. However, the detailed distributions of these compounds have not been determined. Here...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/RR0501.1
更新日期：2007-01-01 00:00:00
abstract：:Growth retardation due to exposure to the atomic bomb has been evaluated using repeated measurements of stature from 10 to 18 years of age. A highly significant growth retardation due to the DS86 uterine dose was observed in all trimesters combined and in the first and second trimesters of pregnancy. In the first trim...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1993-04-01 00:00:00
abstract：:Single crystals of disodium beta-glycerophosphate pentahemihydrate (betaGP), Na2x(HO)CH2CH(PO(4)2-)CH2(OH)x5 1/2H2O, were X-irradiated at 77 and 280 K. EPR, ENDOR and FSE techniques were used to study the formation of free radicals in these irradiated crystals to characterize possible reaction mechanisms leading to de...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1998-08-01 00:00:00
abstract：:Groups of rats were administered different doses of X rays (7.5 and 15 Gy), and the effect on the permeability of their lungs was evaluated during a time frame within which radiation pneumonitis develops. Sham-exposed animals served as controls. End points surveyed included lung weight and increases in the total prote...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1993-05-01 00:00:00
abstract：:Evaluating the risk for central nervous system (CNS) effects after whole-body or partial-body irradiation presents challenges due in part to the varied exposure scenarios in the context of occupational, accidental or wartime releases. Risk estimations are further complicated by the fact that robust changes in brain fu...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/RR15413.1
更新日期：2020-01-01 00:00:00
abstract：:The survival of synchronous G1 or asynchronous Chinese hamster ovary cells in vitro to heat treatment may depend on the cellular population density at the time of heating and/or as the cells are cultured after heating. The addition of lethally irradiated feeder cells may increase survival at 10(-3) by as much as 10- t...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1984-01-01 00:00:00
abstract：:The anoxic sensitization of bacterial spores by added H2O2 has been studied. Two mechanistic pathways for damage from H2O2 were found; one of these requires the presence of OH radicals. For this kind of damage, the relationship between H2O2 and OH appears to be that they are reactants. O-2 (and/or HO2), the product of...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1983-04-01 00:00:00
abstract：:Exposure of the major salivary glands to ionizing radiation often results in severe alterations in structure and function. The mechanism of these effects is still unknown, and no adequate prevention or treatment is yet available. The purpose of this study was to examine a mechanism based on the assumption that redox-a...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1998-03-01 00:00:00
abstract：:To elucidate the nature and kinetics of DNA strand breaks caused by low-energy Auger electron emitters, we compared the yields of DNA breaks in supercoiled pUC19 DNA in the presence of the (.)OH scavenger dimethyl sulfoxide (DMSO) after the decay of (125)I (1) in proximity to DNA after minor-groove binding ((125)I-iod...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1999-11-01 00:00:00
abstract：:The linear no-threshold extrapolation from a dose-response relationship for ionizing radiation derived at higher doses to doses for which regulatory standards are proposed is being challenged by some scientists and defended by others. It appears that the risks associated with exposures to doses of interest are below t...
journal_title：Radiation research
pub_type：
doi：
更新日期：1998-12-01 00:00:00
abstract：:We have previously used NotI as the marker enzyme (recognizing GCGGCCGC) in a genome scanning approach for detection of mutations induced in mouse spermatogonia and estimated the mutation induction rate as about 0.7 x 10(-5) per locus per Gy. To see whether different parts of the genome have different sensitivities fo...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/RR0926.1
更新日期：2007-08-01 00:00:00
abstract：:The induction of intracellular DNA strand breaks by X rays and various heavy charged particles was measured by the alkaline unwinding and alkaline and neutral filter elution techniques. No variations in strand break induction were found between the different cell lines under investigation. For a given particle, both t...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1993-07-01 00:00:00
abstract：:The response of the testes of two strains of adult rats (Sprague-Dawley and Wistar) to graded single doses and split doses of 230 kVp X rays has been investigated. A marked difference was noted between the strains in the response of the clonogenic spermatogonia to irradiation, as measured histologically by the repopul...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1987-10-01 00:00:00
abstract：:Synchrotron microbeam radiation treatment (MRT) is a preclinical radiotherapy technique with considerable clinical promise, although some of the underlying radiobiology of MRT is still not well understood. In recently reported studies, it has been suggested that MRT elicits a different tumor immune profile compared to...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/RR14115.1
更新日期：2016-01-01 00:00:00
abstract：:Damage to intestine is a serious problem after accidental radiation exposure. To examine substances to ameliorate damage by postirradiation administration, we focused on the regeneration process after irradiation of the intestine. Using experimental systems, the effects of clinically used sex hormones on regeneration ...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/RR2154.1
更新日期：2011-03-01 00:00:00
abstract：:These assessment of the consequences of irradiation on chromatin is complicated by endogenous nucleases. Isolation and prolonged storage of rat liver nuclei in buffers containing divalent metal ions activates these enzymes and promotes the degradation of chromatin. Irradiation of rat liver nuclei to dose levels of 20,...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1984-08-01 00:00:00
abstract：:The induction of thymic lymphomas by whole-body X irradiation with four doses of 1.8 Gy (total dose: 7.2 Gy) in C57BL/6 mice was suppressed from a high frequency (90%) to 63% by preirradiation with 0.075 Gy X rays given 6 h before each 1.8-Gy irradiation. This level was further suppressed to 43% by continuous whole-bo...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/rr3289
更新日期：2005-02-01 00:00:00
abstract：:Chinese hamster ovary cells were irradiated with 250 kVp X rays and analyzed for the presence of DNA double-strand breaks using either polycarbonate filter elution or pulsed-field agarose gel electrophoresis at neutral pH. Reduction in DNA length detected by filter elution was produced as a nonlinear function of incre...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1990-12-01 00:00:00
abstract：:This report presents the results of an investigation of changes in the number of erythroid and granulocyte-macrophage colony-forming cells (GM-CFC) that had occurred in tissues of normal B6D2F1 mice 20 h after administration of a radioprotective dose (150 ng) of human recombinant interleukin-1 (rIL-1). Neutrophilia in...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1990-02-01 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：:The non-human primate has been a useful model for studies of human acute radiation syndrome (ARS). However, to date structural changes in various parts of the intestine after total body irradiation (TBI) have not been systematically studied in this model. Here we report on our current study of TBI-induced intestinal s...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/RR14191.1
更新日期：2015-11-01 00:00:00
abstract：:We have tested an 836.55 MHz field with North American Digital Cellular (NADC) modulation in a 2-year animal bioassay that included fetal exposure. In offspring of pregnant Fischer 344 rats, we tested both spontaneous tumorigenicity and the incidence of induced central nervous system (CNS) tumors after a single dose o...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1999-09-01 00:00:00
abstract：:Evaluation of the characteristics of accelerator-based thermal neutron fields is recognized as an important issue when discussing the effectiveness of boron neutron capture therapy (BNCT). In this study, we propose that the radiation chemical yield (G value) of hydroxyl radicals (Goh•) can be considered a universal pa...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/RR15318.1
更新日期：2019-05-01 00:00:00
abstract：:Radiation sensitivity was measured by the micronucleus assay in T lymphocytes of the spleen and in fibroblasts derived from three inbred strains of mice, BALB/c, A/J and C3H/He. A linear correlation between the surviving fraction and the micronucleus frequency was obtained. There were clear differences in the radiosen...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1997-10-01 00:00:00
abstract：:Resistance to radiation is considered to be an important reason for local failure after radiotherapy and tumor recurrence. However, the exact mechanisms of tumor resistance remain poorly understood. Current investigations of microRNAs as potential diagnostic and therapeutic tools for cancer treatment have shown promis...
journal_title：Radiation research
pub_type： 杂志文章,评审
doi：10.1667/RR14370.1
更新日期：2016-06-01 00:00:00
abstract：:We recently reported that daily dietary supplementation with 100 µg selenium (a dose exceeding a rat's nutritional requirement by about 33-fold) initiated immediately after total-body irradiation (TBI) and maintained for 21 weeks mitigates radiation nephropathy in a rat model as indicated by blood urea nitrogen (BUN) ...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/rr2456.1
更新日期：2011-09-01 00:00:00
abstract：:Two different sets of Monte Carlo computations were carried out for the study of dose penetration of monoenergetic, low-energy (10 to 100 keV) photon beams incident on slabs of tissue. One program took into account coherent scattering and considered electron binding when finding the angle of scattering during incohere...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1983-11-01 00:00:00
abstract：:The influence of antibiotic decontamination of Pseudomonas contamination of the GI tract prior to whole-body neutron or gamma irradiation was studied. It was observed that for fission neutron doses greater than 5.5 Gy, cyclotron-produced neutron doses greater than 6.7 Gy, and 137Cs gamma-ray doses greater than 14.4 Gy...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1985-12-01 00:00:00
abstract：:To examine the role of radiation energy deposition in DNA on cellular effects, we investigated the ability of 125IdUrd and 131IdUrd to kill cells and induce mutations at the hprt locus. We employed human lymphoblastoid cells proficient (TK6) or deficient (SE30) in the ability to incorporate a thymidine analog into DNA...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1990-07-01 00:00:00
