Abstract：
:This study was undertaken to investigate the mechanism of chemical radiosensitization by halogenated bases incorporated into DNA. Radiation-induced base and sugar-phosphate backbone damage to 5-bromouridine-5'-monophosphate (5-BrUMP) was monitored using a flow system connected in series with a recording spectrophotometer, a bromide (Br-)-specific ion analyzer and a Technicon auto-sampler. The system was used to assay loss of UV-absorbing 5,6 double-bond, release of Br- and inorganic phosphate (Pi) release using an automated colorimetric method, as a function of gamma-ray dose. Results obtained with radical scavengers indicate that, unlike non-halogenated nucleotides where the hydroxyl radical (.OH) is the principal damaging species, 5-BrUMP is damaged by the hydrated electron (e-aq), hydrogen atom (H.) and .OH, producing a high yield of base damage and Br- and Pi release in anoxia. Another novel feature of 5-BrUMP radiolysis is that oxygen, by converting e-aq and H. to the unreactive superoxide radical anion (O2-), has a protective effect on both base and phosphate ester damage. Under .OH-scavenging conditions, where the radiation yield of reductive debromination is 3.8, there is some Pi release, suggesting the possibility of intramolecular hydrogen atom transfer from the sugar ring to the 5-uracilyl radical and subsequent sugar-phosphate bond cleavage. This hypothesis is supported by the action of oxygen and thiols in modifying the e-aq-mediated sugar-phosphate damage.
journal_name
Radiat Environ Biophysjournal_title
Radiation and environmental biophysicsauthors
Greenstock CL,Whitehouse RPdoi
10.1007/BF01211508keywords:
subject
Has Abstractpub_date
1992-01-01 00:00:00pages
1-9issue
1eissn
0301-634Xissn
1432-2099journal_volume
31pub_type
杂志文章abstract：:The problem of expressing cumulative detrimental effect of radiation exposure is revisited. All conventionally used and computationally complex lifetime or time-integrated risks are based on current population and health statistical data, with unknown future secular trends, that are projected far into the future. It i...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/s00411-019-00794-1
更新日期：2019-08-01 00:00:00
abstract：:The radiation-induced process of strand breaks on pBR322 plasmid DNA in aqueous solution for different energy electrons was studied by Monte Carlo simulation. Assumptions of induction mechanisms of single- and double-strand breaks (SSBs and DSBs) used in the simulation are that SSB is induced by OH or H reaction with ...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/s00411-002-0161-8
更新日期：2002-09-01 00:00:00
abstract：:Survival and G2 dalay following exposure to either 60Cobalt-gamma-rays or 241Americium-alpha-particles were studied in eight mammalian cell lines of human and animal origin including human fibroblasts from normal individuals and from patients with Ataxia telangiectasia or Fanconi's anemia. For both endpoints the effec...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/BF01325466
更新日期：1982-01-01 00:00:00
abstract：:The aim of this study was to detect membrane fluidity modifications in blood lymphocytes that had been exposed to gamma-radiation, at a graded series of depths from the surface to the centre of the membrane bilayer and as a function of cell viability. A time course was performed to verify the contribution of the membr...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/s004110100104
更新日期：2001-09-01 00:00:00
abstract：:The naturally synchronous development of early mouse embryos was exploited to address the question, whether micronuclei require a mitosis for expression or whether they can be expressed in the same cell cycle, in which exposure to X-rays or caffeine took place. Experiments with 2-cell and with 4-cell embryos showed th...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/BF01219345
更新日期：1991-01-01 00:00:00
abstract：:Our recent results suggest that 50 Hz magnetic fields (MF) enhance ultraviolet (UV)-induced tumorigenesis in mouse skin. The aim of the present experiment was to study suppression of apoptosis as a possible mechanism for MF effects on skin tumorigenesis. Another aim was to test the importance of a UV and MF exposure s...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/s00411-002-0153-8
更新日期：2002-06-01 00:00:00
abstract：:Bone sarcoma as a second malignancy is rare but highly fatal. The present knowledge about radiation-absorbed organ dose-response is insufficient to predict the risks induced by radiation therapy techniques. The objective of the present study was to assess the treatment-induced risk for bone sarcoma following a childho...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/s00411-013-0510-9
更新日期：2014-05-01 00:00:00
abstract：:The non-random distribution of DNA breakage in pulsed-field gel electrophoresis (PFGE) experiments poses a problem of proper subtraction of the background damage to obtain a fragment-size distribution due to radiation only. As been pointed out by various authors, a naive bin-to-bin subtraction of the background signal...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/s00411-007-0098-z
更新日期：2007-06-01 00:00:00
abstract：:125I incorporated in DNA is known to be exceptionally toxic. Values of D0 range from about 40 to about 90 decays for survival of mammalian cells. The effectiveness of 125I in DNA with respect to the induction of breaks of the DNA strands, however, appears to be comparatively low. The numbers of strand breaks per energ...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/BF01213705
更新日期：1987-01-01 00:00:00
abstract：:The Auger electron emitter 123I was examined in the form of 4-[123I]iodoantipyrine and as [123I]NaI for its effectiveness in killing cells of different sensitivity to photon irradiation. Micronucleus assays showed that 4-[123I]iodoantipyrine is 2-3 times more effective in cell inactivation than [123I]NaI. This can be ...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/s004110000083
更新日期：2001-03-01 00:00:00
abstract：:The oxyhemoglobin saturation (HbO2) of single red blood cells within tumor microvessels (diameter: 3-12 micrometers) of DS-Carcinosarcoma was studied using a cryophotometric micromethod. In untreated control tumors (mean tissue temperature approx. 35 degrees C) the measured values scattered over the whole saturation r...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/BF01323754
更新日期：1982-01-01 00:00:00
abstract：:Testing the limits of survivability in space is the primary focus in astrobiological research. Although a number of previous studies have examined terrestrial life survival in an extraterrestrial environment, only a few have investigated how life systems respond to high doses of alpha cosmic ray, the main component of...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/s00411-019-00803-3
更新日期：2019-08-01 00:00:00
abstract：:To explore possible applications of iodoacetate (IA), a glycolytic inhibitor, in cancer treatment, we screened its cytotoxicity and radioprotective/sensitizing efficacy in three different mammalian cell lines; A549 (human lung carcinoma), MCF7 (human mammary cancer), a non-cancerous CHO (Chinese hamster ovary) cells a...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/s00411-017-0699-0
更新日期：2017-08-01 00:00:00
abstract：:The migration of radionuclides from waste repositories to the biosphere potentially leads to a contamination of soil. Due to the importance of food production, the mobilisation and accumulation behaviour of long-lived radionuclides in the soil plays a key role in performance assessment studies. In this paper, the main...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章,评审
doi：10.1007/s004110100098
更新日期：2001-06-01 00:00:00
abstract：:The effect of ionizing irradiation on the physiological activity of cyclic adenosine monophosphate (cAMP) in smooth muscle preparations from frog lung was studied. cAMP, given as dibutyryl salt (dib-cAMP) inhibited the radiation induced contractions of the muscle in a manner similar to the action of theophylline. In v...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/BF01323750
更新日期：1982-01-01 00:00:00
abstract：:Indoor exposure to natural radon is a factor that influences lung cancer risk worldwide. The present study includes a meta-analysis of epidemiological data on the relationship between lung cancer and indoor radon. Altogether, 31 case-control studies with 20,703 cases, 34,518 controls and 140 individual odds ratio (OR)...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章,meta分析
doi：10.1007/s00411-018-0770-5
更新日期：2019-03-01 00:00:00
abstract：:Large lung sections of humans of advanced adult age revealed a markedly nonuniform retention pattern of dense anthracotic particle aggregates, with an impressive accumulation of this material along pulmonary lymphatics, i.e. the deep (peribronchial), septal (perivenous) and superficial (pleural) networks. Conversely, ...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/BF01221972
更新日期：1987-01-01 00:00:00
abstract：:Exposure to ionizing radiation has well-documented long-term effects on cancer rates and other health outcomes in humans. While in vitro experimental studies had demonstrated that the nature of some radiation effects depend on both total dose of the radiation and the dose rate (i.e., the pattern of dose distribution o...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/s00411-016-0670-5
更新日期：2017-03-01 00:00:00
abstract：:One of the main purposes leading botanists to investigate the effects of ionizing radiations is to understand plant behaviour in space, where vegetal systems play an important role for nourishment, psychological support and functioning of life support systems. Ground-based experiments have been performed with particle...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章,评审
doi：10.1007/s00411-010-0343-8
更新日期：2011-03-01 00:00:00
abstract：:The potential mechanisms underlying the increase in serum iron concentration in gamma-irradiated mice were studied. The gamma irradiation dose used was 4 Gy, and cobalt-60 ((60)Co) source was used for the irradiation. The dose rate was 0.25 Gy/min. In the serum of irradiated mice, the concentration of ferrous ions dec...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/s00411-015-0623-4
更新日期：2016-03-01 00:00:00
abstract：:The aim of this study was to verify whether extremely low frequency (ELF) magnetic fields (MF) could affect transposition activity like some environmental stress factors such as heat shock or UV irradiation. Using an Escherichia coli Lac Z(-) strain transformed with a plasmid containing a Tn 10 derivative element expr...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/s00411-003-0192-9
更新日期：2003-07-01 00:00:00
abstract：:In the mountainous "Hohe Tauern" region of Salzburg (Austria), milk samples have been collected in a long-term montitoring programme since 1988, at eight alpine sites used for extensive, seasonal stock farming. For this alpine environment with its acidic soils developed on silicate bedrock, high soil-to-plant transfer...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/s00411-008-0192-x
更新日期：2009-02-01 00:00:00
abstract：:Blue (F450) and green (F530) leaf fluorescence were studied together with the red chlorophyll fluorescence (emission maxima F690 and F735) during light-induced chlorophyll fluorescence induction kinetics (Kautsky effect) in predarkened leaves of wheat (Triticum aestivum L.) and soybean (Glycine max L.). The intensity ...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/BF01225923
更新日期：1993-01-01 00:00:00
abstract：:The effect of gamma radiation on red blood cells have been examined using a spin labeling method. For this purpose two spin labels were used to monitor membrane fluidity: methyl 5-doxylpalmitate (Met 5-DP) and methyl 12-doxylstearate (Met 12-DS). The irradiation of red cells with the doses of 200 and 500 Gy caused dec...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/BF01595573
更新日期：1991-01-01 00:00:00
abstract：:Combined action of irradiation (IR), shear stress, and high blood pressure is well recognized to induce damage to vasculature, while data on pathological effects of IR in large peripheral vessels with low blood pressure are scarce. The purpose of the present study was hence to investigate time- and dose-dependent effe...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/s00411-013-0492-7
更新日期：2014-03-01 00:00:00
abstract：:Data on rats exposed to cigarette smoke before or after exposure to radon are used to estimate smoke-dependent parameters of the biologically based two-stage clonal expansion model. The baseline parameters and the action of radon acting on initiation and promotion were fixed based on earlier work. Cigarette smoke acti...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/s00411-005-0006-3
更新日期：2005-10-01 00:00:00
abstract：:The effect of supplying three different stable iodine levels (about 70, 80, and 160 mg day-1) in the daily feed of four dairy cows has been studied for the excretion pattern of 131I. None of the different treatments had a statistically significant effect. A mean milk transfer coefficient of 0.015 +/- 0.001 d l-1 was d...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/BF01212680
更新日期：1994-01-01 00:00:00
abstract：:The main target of this work is to examine blood clearance and external exposure for 177Lu-DOTATATE compared with new emerging 177Lu-PSMA therapy. Blood clearance and radiation exposure of 31 patients treated with 5.5 ± 1.1 GBq 177Lu-DOTATATE were compared to those of 23 patients treated with 7.4 GBq 177Lu-PSMA. Dose ...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/s00411-017-0721-6
更新日期：2018-03-01 00:00:00
abstract：:The hypoxic cytotoxic effect of chlorpromazine towards E. coli B/r was observed to be dependent on temperature of incubation and irradiation. Increasing the temperature of incubation from ambient to 37 degrees C followed by irradiation revealed that the organisms showed radiosensitivity of a magnitude which was two to...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/BF01229816
更新日期：1985-01-01 00:00:00
abstract：:137Cs from global fallout of nuclear weapon testings in the 1950s and 1960s was determined in successive layers (0-30 cm) of eight undisturbed grassland soils in Bavaria, Germany. The maximum activity concentration was found in soil layers between 4 and 15 cm below the surface. Using the vertical distribution of the c...
journal_title：Radiation and environmental biophysics
pub_type： 杂志文章
doi：10.1007/s004110050088
更新日期：1998-04-01 00:00:00
