Abstract:
PURPOSE:Hypoxic cells in tumours are resistant to 5-fluorouracil (5-FU). This in vivo study investigated the ability of hypoxia to regulate the gene expression of thymidylate synthase (TS), the target enzyme of 5-FU. MATERIALS AND METHODS:C3H mammary carcinomas, grown in the feet of female CDF1 mice, were used for all experiments. Mice were placed in a 10% oxygen environment for various time periods and the tumour oxygen status was determined with an Eppendorf oxygen electrode. The animals were then injected with BrdU (100 mg/kg, i.p.). Tumours were excised and immediately frozen (-80 degrees C) until isolation of total RNA. The mRNA was reversibly transcribed to complementary DNA and the resulting cDNA amplified in a multiplex PCR reaction, with beta-actin as the internal reference gene. RESULTS:One hour of low oxygen breathing made tumours significantly more hypoxic. This increase was maintained for a maximum incubation period of 48 h. In the same tumours, no change in TS gene expression was seen with up to 3 h of low oxygen breathing. At longer times it decreased, reaching significance at 12-24 h and remaining at this lower level for up to 48 h. BrdU labelling was significantly reduced after breathing low O2 for 24 h (p = 0.001). CONCLUSION:Hypoxia-induced down-regulation of TS gene expression was observed. This would be expected to make hypoxic tumour cells more sensitive to 5-FU. Other mechanisms must be responsible for the previously reported resistance to this drug.
journal_name
Int J Radiat Bioljournal_title
International journal of radiation biologyauthors
Ehrnrooth E,von der Maase H,Sørensen BS,Poulsen JH,Horsman MRdoi
10.1080/095530099139944subject
Has Abstractpub_date
1999-07-01 00:00:00pages
885-91issue
7eissn
0955-3002issn
1362-3095journal_volume
75pub_type
杂志文章abstract:PURPOSE:To assess health, growth and reproductive success of mammals exposed for multiple generations to levels of radium-226 known to occur in environments surrounding uranium mines and mills in Canada. METHODS:The study consisted of a control group and four treatment groups each containing 40 mice (20 males and 20 f...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.3109/09553002.2015.1028598
更新日期:2015-07-01 00:00:00
abstract::The bacterial enzyme PvuII, which generates blunt-ended DNA double-strand breaks, and T4 DNA ligase, which seals adjacent DNA fragments in coupling to ATP cleavage, were introduced in mouse C3H10T1/2 fibroblasts using osmolytic shock of pinocytic vesicles. Cells were then assayed for their clonogenic ability. In agree...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553009114550851
更新日期:1991-04-01 00:00:00
abstract::Because of the role that alveolar macrophages (PAM) play in the pulmonary clearance of inhaled particles via mechanical transport and dissolution, understanding the uptake and dissolution of particles by these cells might provide insight into the mechanisms of particle dissolution in lungs of various species and hence...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553009214551861
更新日期:1992-07-01 00:00:00
abstract::Purpose: Projects evaluating the effects of radiation, within the National Institutes of Quantum and Radiological Science and Technology (QST), National Institute of Radiological Sciences (NIRS), have focused on risk analyses for life shortening and cancer prevalence using laboratory animals. Genetic and epigenetic al...
journal_title:International journal of radiation biology
pub_type: 杂志文章,评审
doi:10.1080/09553002.2019.1625458
更新日期:2019-10-01 00:00:00
abstract:PURPOSE:To investigate the possible role of cell cycle arrest in the radiosensitization of mouse spermatogonial stem cells due to small conditioning X-ray exposures. MATERIALS AND METHODS:A 24 h fractionation interval between conditioning (1 Gy) and challenging (8 or 9 Gy) exposures was used. Two approaches were follo...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553000010009035
更新日期:2001-03-01 00:00:00
abstract::Induction of mutations to 6-thioguanine resistance (TGr) by gamma-rays at three different dose-rates and molecular changes in the HPRT gene were studied in human lymphoblastoid WIL2-NS cells. Mutant induction showed a curvilinear dose-response for acute irradiation (30 Gy/h). The total mutant frequency was lower after...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/095530096145201
更新日期:1996-08-01 00:00:00
abstract:PURPOSE:This study was undertaken to understand the roles of RecA and RecF proteins in strand break rejoining and maintenance of fidelity of the process following exposure of E. coli to gamma-radiation in vivo. MATERIALS AND METHODS:A plasmid DNA construct, pMTa4, was transformed into isogenic repair proficient (wild)...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553000601121140
更新日期:2007-02-01 00:00:00
abstract::During previous studies on the relationship between thermosensitivity and intracellular pH (pHi) regulation in mammalian cells, we observed that the thermoresistant TR-4 cells appeared to be resistant to manipulations of the Na+/H+ antiport, one of the two primary membrane regulators of pHi. We hypothesized that this ...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/095530096144969
更新日期:1996-10-01 00:00:00
abstract:PURPOSE:The tumour suppressor protein p53 is considered to have an impact on the radiosensitivity of tumour cells. However, this concept does not easily translate to the tumour sensitivity in the clinics. The aim of the present study was to determine whether a functional or dysfunctional p53 is associated with a sensit...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553000310001642902
更新日期:2004-01-01 00:00:00
abstract:PURPOSE:To determine the relationships between the frequencies of radiation-induced chromosomal alterations and the extent of apoptosis in G0 human lymphocytes. MATERIAL AND METHODS:G0 human peripheral blood lymphocytes (HPBL) were X or gamma-irradiated, in the presence or absence of the repair inhibitor cytosine arab...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553000500303690
更新日期:2005-08-01 00:00:00
abstract::The repair activity of verbascoside (VER), isolated from Pedicularis spicata, towards the oxidizing hydroxyl radical adduct of dGMP and its reaction mechanism were studied using pulse radiolysis. Upon pulse radiolysis of nitrous oxide saturated aqueous solution of 2'-deoxyguanosine-5'-monophosphate (dGMP) and VER, it ...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/095530096145779
更新日期:1996-04-01 00:00:00
abstract:PURPOSE:To evaluate the radioprotective effect of dieckol, a component of the brown algae Ecklonia cava. MATERIALS AND METHODS:Mice were lethally irradiated, treated with dieckol and surveyed for survival and the mechanism of radioprotection. RESULTS:Dieckol treatment lengthened the survival of irradiated mice and si...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.3109/09553002.2010.487011
更新日期:2010-10-01 00:00:00
abstract::This study evaluated the cell-mediated (CMI) and humoral immune responses in four Beagle dogs five to six years after single inhalation exposures to different monodisperse 239PuO2 aerosols (0.72-1.4 microns activity median aerodynamic diameter). These exposures resulted in initial lung burdens ranging from 19 to 35 kB...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553008914550311
更新日期:1989-02-01 00:00:00
abstract:PURPOSE:To investigate the influence of chromatin organization and scavenging capacity in relation to irradiation temperature on the induction of double-strand breaks (DSB) in structures derived from human diploid fibroblasts. MATERIALS AND METHODS:Agarose plugs with different chromatin structures (intact cells+/-wort...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553000310001610204
更新日期:2003-10-01 00:00:00
abstract:PURPOSE:The long-term effect of low and moderate doses of ionizing radiation on the lens is still a matter of debate and needs to be evaluated in more detail. MATERIAL AND METHODS:We conducted a detailed histological analysis of eyes from B6C3F1 mice cohorts after acute gamma irradiation (60Co source; 0.063 Gy/min) at...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553002.2021.1876951
更新日期:2021-01-19 00:00:00
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::It is well established from clinical, epidemiological and laboratory studies that specific human germ line mutation can predispose to spontaneously arising cancer. Some of the responsible genes have been characterized at the molecular level and evidence is rapidly accumulating on mechanistic aspects of the problem. A ...
journal_title:International journal of radiation biology
pub_type: 杂志文章,评审
doi:10.1080/09553009414551761
更新日期:1994-11-01 00:00:00
abstract::Purpose To investigate the effect of increasing the overall treatment time as well as delivering the compensating doses on the Balb/c breast adenocarcinoma (4T1) tumor. Materials and methods A total of 72 mice were divided into two aliquots (classes A and B) based on the initial size of their induced tumor. Each class...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.3109/09553002.2016.1117677
更新日期:2016-01-01 00:00:00
abstract:PURPOSE:To investigate the consequence of continuous low dose-rate exposure to gamma-rays on ornithine decarboxylase (ODC EC 4.1.1.17) activity in organs of rat. MATERIALS AND METHODS:Young male Wistar rats were irradiated at 1.1, 2.1 and 12.9 cGy/day in the dose ranges of 9-165, 17-315 and 100-2000 cGy, respectively,...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/095530099140645
更新日期:1999-02-01 00:00:00
abstract:PURPOSE:The main aim of the present study is to gain mechanistic insights into the modulating effect of molecular hydrogen on the γ-radiation-induced alteration pathways of DNA nucleobases. MATERIALS AND METHODS:Aerated aqueous solutions of calf thymus DNA were exposed to a (60)Co source at doses ranging from 0 to 55 ...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553002.2016.1206234
更新日期:2016-09-01 00:00:00
abstract:PURPOSE:To reduce retention and toxicity of the alpha particle emitter polonium-210 in rats by newly developed chelating agents. MATERIALS AND METHODS:Repeated subcutaneous chelation was conducted after intravenous injection of 210Po nitrate. For reduction of 210Po retention the treatment with vicinal dithiols meso-an...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553000050151691
更新日期:2000-10-01 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::Objective: To quantify DNA damage in patients undergoing non-contrast and contrast-enhanced 18F-FDG PET/CT whole body positron emission tomography/computed tomography (WB PET/CT) investigations using comet assay technique and micronucleus assay, and to study the effect of other baseline parameters of patients on DNA d...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553002.2019.1577569
更新日期:2019-06-01 00:00:00
abstract::The accumulation and repair of radiation-induced DNA double-strand breaks (dsbs) were determined by neutral filter elution on 20 primary cultures obtained from ovarian cancer and malignant melanoma clinical specimens. The initial frequency of DNA dsbs after exposure to 50 Gy gamma-irradiation varied greatly for the in...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553009414551211
更新日期:1994-09-01 00:00:00
abstract:PURPOSE:Epidemiological studies have demonstrated a possible correlation between exposure to extremely low-frequency magnetic fields (ELF-MF) and cancer. However, this correlation has yet to be definitively confirmed by epidemiological studies. The principal objective of this study was to assess the effects of 60 Hz ma...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.3109/09553002.2012.652724
更新日期:2012-04-01 00:00:00
abstract::One of the major goals of cancer research is to identify and understand the causes of cellular proliferation. The role of cell death, or lack thereof, in carcinogenesis, tumour growth, metastatic spread and response to treatment has been largely overlooked even though the morphology of apoptosis (programmed cell death...
journal_title:International journal of radiation biology
pub_type: 杂志文章,评审
doi:10.1080/095530097143789
更新日期:1997-05-01 00:00:00
abstract::The effect of a siderophore analogue 3,4,3-LIHOPO has been investigated in rat after intramuscular injection of 238Pu, 239Pu and 241Am simulating puncture wounds. Various treatment regimens were used to remove the radioactivity from its injection site and to reduce its retention in body tissues. The local deposits cou...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/095530096145382
更新日期:1996-07-01 00:00:00
abstract:PURPOSE:Static magnetic field (SMF) exposure was shown experimentally to beneficially affect the healing process. The aim of this randomized, controlled trial was to evaluate the pain-inhibitory effect of local exposure to SMF on temporomandibular disorders, on alveolitis and on aphta in the oral mucosa. MATERIALS AND...
journal_title:International journal of radiation biology
pub_type: 杂志文章,随机对照试验
doi:10.3109/09553002.2012.661916
更新日期:2012-05-01 00:00:00
abstract:PURPOSE:Genotoxic effects have been considered the gold standard to determine if an environmental factor is a carcinogen, but the currently available data for extremely low frequency time-varying magnetic fields (ELF-MF) remain controversial. As an environmental stimulus, the effect of ELF-MF on cellular DNA may be sub...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.3109/09553002.2014.887866
更新日期:2014-04-01 00:00:00
abstract::We have measured clonal survival following gamma-irradiation of unstimulated (G0) T-lymphocytes from 35 donors, of 11 T-lymphocyte cell lines, of six lymphoblastoid cell lines, and of nine primary fibroblast strains for which we have G0 T-lymphocyte material from the same donor. Amongst the G0 lymphocytes we have resu...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553008814552331
更新日期:1988-12-01 00:00:00