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Sample records for altered radiation sensitivity

  1. Altered metaphase chromosome structure in xrs-5 cells is not related to its radiation sensitivity or defective DNA break rejoining

    International Nuclear Information System (INIS)

    The Chinese hamster ovary (CHO) cell line xrs-5 is a radiation-sensitive derivative of CHO-K1 cells. The xrs-5 cells have a defect in DNA double-strand break rejoining and show alterations in chromosome structure and nuclear morphology. The relationship between radiation sensitivity and metaphase chromosome morphology was examined in 12 'revertant' xrs-5 clones isolated following treatment with 5-azacytidine. Nine of the clones were radioresistant while the other three retained xrs-5-like radiation sensitivity. Chromosome morphology reverted to CHO-K1-like characteristics in three of the radioresistant clones and one of the radiosensitive clones suggesting that the over-condensed metaphase chromosome morphology of xrs-5 cells does not underlie its radiation sensitivity. Radiation sensitivity did correlate with DNA double-strand break rejoining ability. The radioresistant clones showing the over-condensed xrs-5-like chromosome morphology were also slightly more sensitive to the topoisomerase II inhibitor etoposide (VP-16) than CHO-K1, suggesting that the over-condensed morphology might be due to alterations in the phosphorylation of chromatin proteins

  2. Radiation sensitizers

    International Nuclear Information System (INIS)

    The following classes of radiosensitizers are discussed: electron affinic compounds, pyrimidine analogs, and antibiotics. Metronidazole and nitroimidazole are discussed as examples of electron-affinic compounds. Studies on the enhancement ratio for sensitization of x-irradiated hamster cells showed that these drugs sensitize at concentrations much lower than the toxic concentrations. Criteria for a clinically useful hypoxic cell sensitizer are listed and mechanisms of electron-affinic sensitizers are discussed. The radiosensitizing effects of the pyrimidine analogs, BUDR, BCDR, IUDR, CUDR, and FUDR, are examined and the enhancement of radiation effects by the chemotherapeutic agent, 5-fluorouracil, is discussed. Other agents discussed are methotrexate, actinomycin D, bleomycin, and adriamycin

  3. Low-power millimeter wave radiations do not alter stress-sensitive gene expression of chaperone proteins.

    Science.gov (United States)

    Zhadobov, M; Sauleau, R; Le Coq, L; Debure, L; Thouroude, D; Michel, D; Le Dréan, Y

    2007-04-01

    This article reports experimental results on the influence of low-power millimeter wave (MMW) radiation at 60 GHz on a set of stress-sensitive gene expression of molecular chaperones, namely clusterin (CLU) and HSP70, in a human brain cell line. Selection of the exposure frequency is determined by its near-future applications for the new broadband civil wireless communication systems including wireless local area networks (WLAN) for domestic and professional uses. Frequencies around 60 GHz are strongly attenuated in the earth's atmosphere and such radiations represent a new environmental factor. An exposure system operating in V-band (50-75 GHz) was developed for cell exposure. U-251 MG glial cell line was sham-exposed or exposed to MMW radiation for different durations (1-33 h) and two different power densities (5.4 microW/cm(2) or 0.54 mW/cm(2)). As gene expression is a multiple-step process, we analyzed chaperone proteins induction at different levels. First, using luciferase reporter gene, we investigated potential effect of MMWs on the activation of transcription factors (TFs) and gene promoter activity. Next, using RT-PCR and Western blot assays, we verified whether MMW exposure could alter RNA accumulation, translation, or protein stability. Experimental data demonstrated the absence of significant modifications in gene transcription, mRNA, and protein amount for the considered stress-sensitive genes for the exposure durations and power densities investigated. The main results of this study suggest that low-power 60 GHz radiation does not modify stress-sensitive gene expression of chaperone proteins. PMID:17080454

  4. X-ray survival characteristics and genetic analysis for nine Saccharomyces deletion mutants that show altered radiation sensitivity.

    Science.gov (United States)

    Game, John C; Williamson, Marsha S; Baccari, Clelia

    2005-01-01

    The availability of a genome-wide set of Saccharomyces deletion mutants provides a chance to identify all the yeast genes involved in DNA repair. Using X rays, we are screening these mutants to identify additional genes that cause increased sensitivity to the lethal effects of ionizing radiation. For each mutant identified as sensitive, we are confirming that the sensitivity phenotype cosegregates with the deletion allele and are obtaining multipoint survival-vs.-dose assays in at least one homozygous diploid and two haploid strains. We present data for deletion mutants involving the genes DOT1, MDM20, NAT3, SPT7, SPT20, GCN5, HFI1, DCC1, and VID21/EAF1 and discuss their potential roles in repair. Eight of these genes cause a clear radiation-sensitive phenotype when deleted, but the ninth, GCN5, results in at most a borderline phenotype. None of the deletions confer substantial sensitivity to ultraviolet radiation, although one or two may confer marginal sensitivity. The DOT1 gene is of interest because its only known function is to methylate one lysine residue in the core of the histone H3 protein. We find that histone H3 mutants (supplied by K. Struhl) in which this residue is replaced by other amino acids are also X-ray sensitive, which confirms that methylation of the lysine-79 residue is required for effective repair of radiation damage. PMID:15371366

  5. X-ray survival characteristics and genetic analysis for nine saccharomyces deletion mutants that show altered radiation sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Game, John C.; Williamson, Marsha S.; Baccari, Clelia

    2004-01-07

    The availability of a genome-wide set of Saccharomyces deletion mutants provides a chance to identify all the yeast genes involved in DNA repair. Using X-rays, we are screening these mutants to identify additional genes that show increased sensitivity to the lethal effects of ionizing radiation. For each mutant identified as sensitive, we are confirming that the sensitivity phenotype co-segregates with the deletion allele and are obtaining multipoint survival-versus-dose assays in at least two haploid and one homozygous diploid strains. We present data for deletion mutants involving the genes DOT1, MDM20, NAT3, SPT7, SPT20, GCN5, HFI1, DCC1 and VID21/EAF1, and discuss their potential roles in repair. Eight of these genes have a clear radiation-sensitive phenotype when deleted, but the ninth, GCN5, has at most a borderline phenotype. None of the deletions confer substantial sensitivity to ultra-violet radiation, although one or two may confer marginal sensitivity. The DOT1 gene is of interest because its only known function is to methylate one lysine residue in the core of the histone H3 protein. We find that histone H3 mutants (supplied by K. Struhl) in which this residue is replaced by other amino-acids are also X-ray sensitive, seeming to confirm that methylation of the lysine-79 residue is required for effective repair of radiation damage.

  6. Radiation sensitive acrylate composition

    International Nuclear Information System (INIS)

    This application relates to radiation-sensitive compositions and more particularly to such compositions comprising acrylated esters. As used in this specification, the term acrylated esters refers to either acrylic or methacrylic acid resins. 3 tabs

  7. Individual radiation sensitivity (gender, age, genetic disposition). Consequences for radiation protection; Individuelle Strahlenempfindlichkeit (Geschlecht-Alter-genetische Disposition). Konsequenzen fuer den Strahlenschutz?

    Energy Technology Data Exchange (ETDEWEB)

    Streffer, C. [Universitaetsklinikum Essen (Germany)

    2013-07-01

    The effects of ionising radiation on human health is influenced by a number of physiological and molecular biological factors. This is also valid for the causation of stochastic radiation effects especially the causation of cancer. Several epidemiological studies have resulted with respect to the total rate of solid cancers that women are more sensitive than men by a factor of 1.6 to 2.0. For leukaemia this is not the case. The largest studies come from the investigations on the survivors of the atomic bombs in Hiroshima and Nagasaki. But also studies on the population of the Techa River (Southeast Urals) yield such data. The analyses of single cancer localizations come to different results with respect to the dependence on the sex. Secondary cancers after radiotherapy for cancer treatment show also higher rates in women than in men. A similar situation is observed with respect to the dependence of cancer rate on age. The total rate of solid cancers is highest with children and decreases with increasing age. The effects are very different again with single cancer localizations. An especially strong age dependence was observed for thyroid cancer. Increasingly individuals have been found who are especially radiosensitive on the basis of their genetic disposition also with respect to the causation of cancer. Mechanisms and possibilities to trace these individuals are discussed. It is also discussed whether and to which extent these data should have consequences for the practical radiological protection. (orig.)

  8. Wound trauma alters ionizing radiation dose assessment

    Directory of Open Access Journals (Sweden)

    Kiang Juliann G

    2012-06-01

    Full Text Available Abstract Background Wounding following whole-body γ-irradiation (radiation combined injury, RCI increases mortality. Wounding-induced increases in radiation mortality are triggered by sustained activation of inducible nitric oxide synthase pathways, persistent alteration of cytokine homeostasis, and increased susceptibility to bacterial infection. Among these factors, cytokines along with other biomarkers have been adopted for biodosimetric evaluation and assessment of radiation dose and injury. Therefore, wounding could complicate biodosimetric assessments. Results In this report, such confounding effects were addressed. Mice were given 60Co γ-photon radiation followed by skin wounding. Wound trauma exacerbated radiation-induced mortality, body-weight loss, and wound healing. Analyses of DNA damage in bone-marrow cells and peripheral blood mononuclear cells (PBMCs, changes in hematology and cytokine profiles, and fundamental clinical signs were evaluated. Early biomarkers (1 d after RCI vs. irradiation alone included significant decreases in survivin expression in bone marrow cells, enhanced increases in γ-H2AX formation in Lin+ bone marrow cells, enhanced increases in IL-1β, IL-6, IL-8, and G-CSF concentrations in blood, and concomitant decreases in γ-H2AX formation in PBMCs and decreases in numbers of splenocytes, lymphocytes, and neutrophils. Intermediate biomarkers (7 – 10 d after RCI included continuously decreased γ-H2AX formation in PBMC and enhanced increases in IL-1β, IL-6, IL-8, and G-CSF concentrations in blood. The clinical signs evaluated after RCI were increased water consumption, decreased body weight, and decreased wound healing rate and survival rate. Late clinical signs (30 d after RCI included poor survival and wound healing. Conclusion Results suggest that confounding factors such as wounding alters ionizing radiation dose assessment and agents inhibiting these responses may prove therapeutic for radiation combined

  9. Radiation sensitive polymer gel dosimeters

    International Nuclear Information System (INIS)

    Full text: Radiation sensitive gels are studied for their potential to retain a permanent 3D dose distribution for applications in radiotherapy. Co-monomers dissolved in a tissue-equivalent hydrogel undergo a polymerization reaction upon absorption of ionizing radiation. The polymer formed influences the local spin-spin relaxation time (T2) of the dosimeter that can be determined using magnetic resonance imaging (MRI). The relationship between T2 and the absorbed dose was studied for different initial chemical compositions. The aim was to find a model linking the changes in T2 with absorbed dose to the initial composition of the dosimeter. It is believed this will help designing new gel dosimeters having desired properties to minimize the uncertainty in the determination of the dose distribution. 1H, 13C nuclear magnetic resonance spectroscopy and FT-Raman spectroscopy were used to quantify the amount of monomers still remaining after the absorption of a given dose of radiation. This data is used to model the changes of T2 as a function of the absorbed dose. A model of fast exchange of magnetization between three proton pools was used, where the fraction of protons (fxH ) in the xth pool is obtained from the chemical composition of the dosimeter and the apparent T2 of each pool is determined for a given composition. Initially, the protons are contained in two pools; a mobile (mob), which contains the water protons and the monomers protons, and a gelatin (gela) proton pool. The mobile pool is partially depleted as polymer is formed, the protons are transferred into the polymer (pol) pool. In the figure, the experimental data along with the calculated values are plotted for three different monomer concentrations, with the gelatin concentration fixed. The model is seen to provide a good fit to the experimental data

  10. Relationship of cataract to radiation sensitivity

    International Nuclear Information System (INIS)

    This investigation was conducted to ascertain whether cellular hypersensitivity to radiation may be identified as a possible cause of cataract in persons exposed to low levels of radiation. Patients were studied in whom posterior subcapsular cataract (PSC) had followed probable exposure to low levels of radiation or in whom PSC had developed before the age of 60 without known exposure. Patients with cataract were compared with age and sex matched controls. Radiation sensitivity was estimated by measuring clonal growth of skin fibroblasts and peripheral blood lymphocytes after exposure to graded doses of radiation and by measuring postirradiation reconstruction of separated nuclear material from lymphocytes. Results show variations in radiation sensitivity between patients, without significant differences from the controls. It is concluded that radiation hypersensitivity is not normally associated with development of posterior subcapsular cataract. (author)

  11. DNA repair and radiation sensitivity in mammalian cells

    International Nuclear Information System (INIS)

    Ionizing radiation induces various types of damage in mammalian cells including DNA single-strand breaks, DNA double-strand breaks (DSB), DNA-protein cross links, and altered DNA bases. Although human cells can repair many of these lesions there is little detailed knowledge of the nature of the genes and the encoded enzymes that control these repair processes. We report here on the cellular and genetic analyses of DNA double-strand break repair deficient mammalian cells. It has been well established that the DNA double-strand break is one of the major lesions induced by ionizing radiation. Utilizing rodent repair-deficient mutant, we have shown that the genes responsible for DNA double-strand break repair are also responsible for the cellular expression of radiation sensitivity. The molecular genetic analysis of DSB repair in rodent/human hybrid cells indicate that at least 6 different genes in mammalian cells are responsible for the repair of radiation-induced DNA double-strand breaks. Mapping and the prospect of cloning of human radiation repair genes are reviewed. Understanding the molecular and genetic basis of radiation sensitivity and DNA repair in man will provide a rational foundation to predict the individual risk associated with radiation exposure and to prevent radiation-induced genetic damage in the human population

  12. Gene Expression Profiling of Biological Pathway Alterations by Radiation Exposure

    OpenAIRE

    Lee, Kuei-Fang; Weng, Julia Tzu-Ya; Hsu, Paul Wei-Che; Chi, Yu-Hsiang; Chen, Ching-Kai; Liu, Ingrid Y.; CHEN, YI-CHENG; Wu, Lawrence Shih-Hsin

    2014-01-01

    Though damage caused by radiation has been the focus of rigorous research, the mechanisms through which radiation exerts harmful effects on cells are complex and not well-understood. In particular, the influence of low dose radiation exposure on the regulation of genes and pathways remains unclear. In an attempt to investigate the molecular alterations induced by varying doses of radiation, a genome-wide expression analysis was conducted. Peripheral blood mononuclear cells were collected from...

  13. Aspects of dosimetry using radiation sensitive gels

    International Nuclear Information System (INIS)

    The use of radiation sensitive gels for dosimetry measurements was first suggested in the 1950s. It was subsequently shown that radiation induced changes in nuclear magnetic resonance (NMR) relaxation properties of gels infused with conventional Fricke dosimetry solutions could be measured. However, due to predominantly diffusion-related limitations, alternative polymer gel dosimeters were suggested. Clinical applications of these radiologically tissue equivalent gel dosimeters using magnetic resonance imaging (MRI) have subsequently been reported in the literature. In Fricke gels, Fe2+ ions in ferrous sulphate solutions are usually dispersed throughout a gelatin or agarose hydrogel matrix. Radiation-induced changes in the dosimeters are considered to be either through direct absorption of ionising radiation or via intermediate water free radicals. Fe2+ ions are converted to Fe3+ ions with a corresponding change in paramagnetic properties that may be quantified using NMR relaxation measurements. In polymer gels, monomers are also dispersed in a gelatin or agarose hydrogel matrix. Monomers undergo a polymerisation reaction as a function of absorbed dose resulting in a three-dimensional polymer gel matrix. The radiation-induced formation of polymer influences NMR relaxation properties. The growth in polymer also results in other physical changes that may be used to quantify absorbed radiation dose. This thesis investigates various aspects of radiation dosimetry using radiation sensitive gels. Image processing software was developed to calculate NMR relaxation images of dosimetry gels. Measurements were undertaken to investigate the diffusion problem in Fricke gels. Radiological properties were theoretically modelled for both Fricke and polymer gels. A methodology was developed for the preparation of polymer gels. Vibrational spectroscopic studies were undertaken to investigate the underlying mechanism involved in the radiation-induced formation of polymer. MRI pulse

  14. Alteration of yeast activity by gamma radiation

    International Nuclear Information System (INIS)

    Yeast is an important component in microbe based industrial technologies. Due to the techno-economic reasons, the fermentation technique has acquired renewed interest. The effect of γ-radiation on the fermentation reaction has been investigated. The studies show that exposure of the fermentation mixture to γ-radiation at 5 kGy enhance alcohol production, whereas irradiation at higher doses, viz., 10 kGy and 25 kGy caused a considerable reduction in the alcohol yield. Therefore, low dose irradiation of fermentation mixtures can be applied for increasing the alcohol production by about 25%. (author). 13 refs., 1 fig

  15. Unique proteomic signature for radiation sensitive patients; a comparative study between normo-sensitive and radiation sensitive breast cancer patients

    Energy Technology Data Exchange (ETDEWEB)

    Skiöld, Sara [Center for Radiation Protection Research, Department of Molecular Biosciences, The Wernner-Gren Institute, Stockholm University, Stockholm (Sweden); Azimzadeh, Omid [Institute of Radiation Biology, German Research Center for Environmental Health, Helmholtz Zentrum München (Germany); Merl-Pham, Juliane [Research Unit Protein Science, German Research Center for Environmental Health, Helmholtz Zentrum München, Neuherberg (Germany); Naslund, Ingemar; Wersall, Peter; Lidbrink, Elisabet [Division of Radiotherapy, Radiumhemmet, Karolinska University Hospital, Stockholm (Sweden); Tapio, Soile [Institute of Radiation Biology, German Research Center for Environmental Health, Helmholtz Zentrum München (Germany); Harms-Ringdahl, Mats [Center for Radiation Protection Research, Department of Molecular Biosciences, The Wernner-Gren Institute, Stockholm University, Stockholm (Sweden); Haghdoost, Siamak, E-mail: Siamak.Haghdoost@su.se [Center for Radiation Protection Research, Department of Molecular Biosciences, The Wernner-Gren Institute, Stockholm University, Stockholm (Sweden)

    2015-06-15

    Highlights: • The unique protein expression profiles were found that separate radiosensitive from normal sensitive breast cancer patients. • The oxidative stress response, coagulation properties and acute phase response suggested to be the hallmarks of radiation sensitivity. - Abstract: Radiation therapy is a cornerstone of modern cancer treatment. Understanding the mechanisms behind normal tissue sensitivity is essential in order to minimize adverse side effects and yet to prevent local cancer reoccurrence. The aim of this study was to identify biomarkers of radiation sensitivity to enable personalized cancer treatment. To investigate the mechanisms behind radiation sensitivity a pilot study was made where eight radiation-sensitive and nine normo-sensitive patients were selected from a cohort of 2914 breast cancer patients, based on acute tissue reactions after radiation therapy. Whole blood was sampled and irradiated in vitro with 0, 1, or 150 mGy followed by 3 h incubation at 37 °C. The leukocytes of the two groups were isolated, pooled and protein expression profiles were investigated using isotope-coded protein labeling method (ICPL). First, leukocytes from the in vitro irradiated whole blood from normo-sensitive and extremely sensitive patients were compared to the non-irradiated controls. To validate this first study a second ICPL analysis comparing only the non-irradiated samples was conducted. Both approaches showed unique proteomic signatures separating the two groups at the basal level and after doses of 1 and 150 mGy. Pathway analyses of both proteomic approaches suggest that oxidative stress response, coagulation properties and acute phase response are hallmarks of radiation sensitivity supporting our previous study on oxidative stress response. This investigation provides unique characteristics of radiation sensitivity essential for individualized radiation therapy.

  16. Unique proteomic signature for radiation sensitive patients; a comparative study between normo-sensitive and radiation sensitive breast cancer patients

    International Nuclear Information System (INIS)

    Highlights: • The unique protein expression profiles were found that separate radiosensitive from normal sensitive breast cancer patients. • The oxidative stress response, coagulation properties and acute phase response suggested to be the hallmarks of radiation sensitivity. - Abstract: Radiation therapy is a cornerstone of modern cancer treatment. Understanding the mechanisms behind normal tissue sensitivity is essential in order to minimize adverse side effects and yet to prevent local cancer reoccurrence. The aim of this study was to identify biomarkers of radiation sensitivity to enable personalized cancer treatment. To investigate the mechanisms behind radiation sensitivity a pilot study was made where eight radiation-sensitive and nine normo-sensitive patients were selected from a cohort of 2914 breast cancer patients, based on acute tissue reactions after radiation therapy. Whole blood was sampled and irradiated in vitro with 0, 1, or 150 mGy followed by 3 h incubation at 37 °C. The leukocytes of the two groups were isolated, pooled and protein expression profiles were investigated using isotope-coded protein labeling method (ICPL). First, leukocytes from the in vitro irradiated whole blood from normo-sensitive and extremely sensitive patients were compared to the non-irradiated controls. To validate this first study a second ICPL analysis comparing only the non-irradiated samples was conducted. Both approaches showed unique proteomic signatures separating the two groups at the basal level and after doses of 1 and 150 mGy. Pathway analyses of both proteomic approaches suggest that oxidative stress response, coagulation properties and acute phase response are hallmarks of radiation sensitivity supporting our previous study on oxidative stress response. This investigation provides unique characteristics of radiation sensitivity essential for individualized radiation therapy

  17. Radiation-induced grafting of sensitive polymers

    International Nuclear Information System (INIS)

    Films of PP and PTFE were modified by gamma-radiation grafting of pH and thermo sensitive monomers (two step method) by using both the preirradiation and the direct methods. The effects of the absorbed dose, monomer concentration and reaction time were investigated. The surface chemistry of grafted samples was analyzed by FTIR-ATR spectroscopy, while their thermal properties were analyzed by TGA and DSC. The stimuli-responsive behavior was studied by swelling and contact angle in water, as well as by DSC. Sensitive films presented a critical pH and LCST. (author)

  18. Individual radiation sensitivity: implications in medical practice

    International Nuclear Information System (INIS)

    Important advances in radiotherapy and nuclear medicine towards better treatment modalities and safer applications have taken place in recent years. Progress in medical imaging, better tumour targeting and optimization of radiation delivery have allowed for dose escalation and improved patient outcome. However, the tolerance of normal tissues constitutes the limiting factor for dose escalation in therapeutical uses of ionizing radiation (IR). Patients vary considerably in their normal tissue response to IR even after similar treatments. As many as 5% of cancer patients develop severe effects to external radiation therapy in normal tissues within the treatment field: they may include acute effects such as erythema and desquamation of the exposed skin and mucosa that appear during or directly after radiotherapy, late effects developed months or years later, such as fibrosis and telangiectasia and cancer induction. Several patient and treatment related factors are known to influence the variability of side effects, however up to a 70% of the total variance of normal tissue radiation response remained unexplained. Thus, individual sensitivity to IR, i.e. hypersensitivity to carcinogenic risks (stochastic effects) and hypersensitivity to deterministic effects, is becoming an important issue in oncology and raises questions regarding the underlying mechanisms. The mechanisms of DNA repair, the signalling pathways involved in radiation sensitivity and non-targeted effects are key aspects, essential to understanding radiation effects at genetic level. Moreover, human genetic diseases that combine higher incidence of cancer and hypersensitivity to IR are associated with defects in cell response to DNA damage. Therefore, much interest has raised during the last years in the developing of predictive tests capable to detect in advance such hypersensitive conditions. The goal of this presentation is to review the possible mechanisms involved in genetic and epigenetic

  19. Individual radiation sensitivity: implications in medical practice

    Energy Technology Data Exchange (ETDEWEB)

    Gisone, P.; Dubner, D.; Perez, M.D.R.; Michelin, S.; Di Giogio, M. [Autoridad Regulatoria Nuclear, Buenos Aires (Argentina); Bourguignon, M. [Direction Generale de la Surete Nucleaire et de la Radioprotection, Paris (France)

    2006-07-01

    Important advances in radiotherapy and nuclear medicine towards better treatment modalities and safer applications have taken place in recent years. Progress in medical imaging, better tumour targeting and optimization of radiation delivery have allowed for dose escalation and improved patient outcome. However, the tolerance of normal tissues constitutes the limiting factor for dose escalation in therapeutical uses of ionizing radiation (IR). Patients vary considerably in their normal tissue response to IR even after similar treatments. As many as 5% of cancer patients develop severe effects to external radiation therapy in normal tissues within the treatment field: they may include acute effects such as erythema and desquamation of the exposed skin and mucosa that appear during or directly after radiotherapy, late effects developed months or years later, such as fibrosis and telangiectasia and cancer induction. Several patient and treatment related factors are known to influence the variability of side effects, however up to a 70% of the total variance of normal tissue radiation response remained unexplained. Thus, individual sensitivity to IR, i.e. hypersensitivity to carcinogenic risks (stochastic effects) and hypersensitivity to deterministic effects, is becoming an important issue in oncology and raises questions regarding the underlying mechanisms. The mechanisms of DNA repair, the signalling pathways involved in radiation sensitivity and non-targeted effects are key aspects, essential to understanding radiation effects at genetic level. Moreover, human genetic diseases that combine higher incidence of cancer and hypersensitivity to IR are associated with defects in cell response to DNA damage. Therefore, much interest has raised during the last years in the developing of predictive tests capable to detect in advance such hypersensitive conditions. The goal of this presentation is to review the possible mechanisms involved in genetic and epigenetic

  20. Radiation curable pressure sensitive adhesive composition

    International Nuclear Information System (INIS)

    Radiation curable pressure sensitive adhesive composition comprises: a polyoxyalkylene homo- or copolymer which is either a polyoxyethylene homopolymer or a poly (oxyethylene-oxypropylene) copolymer, or mixture thereof, having a molecular weight of from 1,700 to 90,000, in which at least 40 percent by weight of the oxyalkylene units are oxyethylene units; a liquid carbamyloxy alkyl acrylate; and, optionally, a photoinitiator

  1. Albendazole sensitizes cancer cells to ionizing radiation

    International Nuclear Information System (INIS)

    Brain metastases afflict approximately half of patients with metastatic melanoma (MM) and small cell lung cancer (SCLC) and represent the direct cause of death in 60 to 70% of those affected. Standard of care remains ineffective in both types of cancer with the challenge of overcoming the blood brain barrier (BBB) exacerbating the clinical problem. Our purpose is to determine and characterize the potential of albendazole (ABZ) as a cytotoxic and radiosensitizing agent against MM and SCLC cells. Here, ABZ's mechanism of action as a DNA damaging and microtubule disrupting agent is assessed through analysis of histone H2AX phosphorylation and cell cyle progression. The cytotoxicity of ABZ alone and in combination with radiation therapy is determined though clonogenic cell survival assays in a panel of MM and SCLC cell lines. We further establish ABZ's ability to act synergistically as a radio-sensitizer through combination index calculations and apoptotic measurements of poly (ADP-ribose) polymerase (PARP) cleavage. ABZ induces DNA damage as measured by increased H2AX phosphorylation. ABZ inhibits the growth of MM and SCLC at clinically achievable plasma concentrations. At these concentrations, ABZ arrests MM and SCLC cells in the G2/M phase of the cell cycle after 12 hours of treatment. Exploiting the notion that cells in the G2/M phase are the most sensitive to radiation therapy, we show that treatment of MM and SCLC cells treated with ABZ renders them more sensitive to radiation in a synergistic fashion. Additionally, MM and SCLC cells co-treated with ABZ and radiation exhibit increased apoptosis at 72 hours. Our study suggests that the orally available antihelminthic ABZ acts as a potent radiosensitizer in MM and SCLC cell lines. Further evaluation of ABZ in combination with radiation as a potential treatment for MM and SCLC brain metastases is warranted

  2. FEU-49 photomultiplier sensitivity to Cherenkov radiation

    International Nuclear Information System (INIS)

    With the aim of verifying the possibility of applying the FEU-19 photomultiplier in large installations for recording the Cherenkov radiation in water, the quantum sensitivity of four specimens of FEU-49 has been measured. The measurements are carried out at a maximum thickness of a distilled water layer equal to 4 cm. The Cherenkov radiation has been produced in water by cosmic muons. Presented are flowsheets used for measuring quantum efficiency of the FEU-49 photocathode and dispersion of its amplification coefficient. By comparing the results of measurements performed with the calculated estimates, a conclusion has been drawn on their good agreements and on suitability of FEU-49 for recording the Cherenkov radiation in water

  3. In vivo radiation sensitivity of glioblastoma multiforme

    International Nuclear Information System (INIS)

    Purpose: Human glioblastoma (GBM) is one of the most resistant tumors to radiation. In previous reports, we have demonstrated a wide range of radiation sensitivity of GBM in vitro; that is, SF2 values of 0.2 to 0.8. The great sensitivity of some of the cell lines is not in accord with the almost invariably fatal clinical outcome of patients with GBM. The sensitivity of cells in vitro pertains to cells cultured in optimal nutritional conditions. The TCD50 (the radiation dose necessary to control 50% of the tumors locally) determined in lab animals is analogous to the use of radiation with curative intent in clinical radiation oncology. The aim of the present study was (a) to evaluate the sensitivity of GBM in vivo relative to that of other tumor types and (b) assess the relationship between the single dose TCD50 of the xenografts and the sensitivity of the corresponding cell lines in vitro. Methods and Materials: The TCD50 assay was used to study twelve human tumor lines. Four previously published values were added. A total of 10 GBM, 4 squamous cell carcinoma (SCC), 1 soft tissue sarcoma (STS), and 1 cancer colon (CC) are included in the analysis. For further suppression of the residual immune system, all the animals received 6 Gy whole-body irradiation 1 day before transplantation. Local tumor irradiations were given as a single dose, under conditions of clamp hypoxia using a Cs irradiator. Results: The TCD50 values for the 10 GBM xenografts varied between 32.5 and 75.2 Gy, with an average of 47.2 ± 13.1 Gy. The TCD50 values for the SCC were similar to those of the GBM and ranged from 40.7 and 54.4 Gy, with a mean of 46.8 ± 6.4. The difference between the average TCD50 of GBM and SCC was not significant. The STS and CC xenografts had TCD50 values of 46.0 and 49.2 Gy, respectively. No correlation was found between the TCD50 in vivo and the SF2 or D0 in vitro. Conclusions: Our data on GBM xenografts showed a wide range of sensitivities to single dose irradiation

  4. Radiation sensitivity of different citric pectins

    Energy Technology Data Exchange (ETDEWEB)

    Inamura, Patricia Y.; Mastro, Nelida L. del [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mails: patyoko@yahoo.com; nlmastro@ipen.br

    2007-07-01

    Pectic substances are important soluble polysaccharides of plant origin of considerable interest for food industry as gelling agent and stabilizer in jams, fruit jellies, yogurt drinks and lactic acid beverages. Polysaccharides can be degraded by ionizing radiation due to the free radical induced scission of the glycosidic bonds. Viscosity methods had been used to determine the efficiency of hydroxyl radical induced chain breaks generation in macromolecules. In the present work samples of pectin with different degree of methoxylation were employed in order to study their radiation sensitivity by means of viscosity measurements. Samples of citric pectin 1% solutions were irradiated with gamma rays at different doses, ranging from 0 to 15 kGy, using a {sup 60}Co Gammacell 220 (AECL), dose rate about 2 kGy/h. After irradiation the viscosity was measured on the viscometer Brookfield model LV-DVIII at 50, 60 and 70 deg C within a period of 48h. Pectin viscosity with high degree of methoxylation decreased sharply with the radiation dose remaining almost constant from 10 kGy. Pectin with low degree of methoxylation presented initially higher values of viscosity and the radiation induced decrease was also pronounced. Viscosity measurements decreased with the increase of the temperature applied for both kind of samples. The effect of radiation induced chain breaks generation in pectin molecules was evident through the viscosity reduction of irradiated pectin solutions although the viscosity presented diverse values depending of the degree of methoxylation of carboxyl groups in the backbone of polysaccharide macromolecules. (author)

  5. Radiation sensitivity of different citric pectins

    International Nuclear Information System (INIS)

    Pectic substances are important soluble polysaccharides of plant origin of considerable interest for food industry as gelling agent and stabilizer in jams, fruit jellies, yogurt drinks and lactic acid beverages. Polysaccharides can be degraded by ionizing radiation due to the free radical induced scission of the glycosidic bonds. Viscosity methods had been used to determine the efficiency of hydroxyl radical induced chain breaks generation in macromolecules. In the present work samples of pectin with different degree of methoxylation were employed in order to study their radiation sensitivity by means of viscosity measurements. Samples of citric pectin 1% solutions were irradiated with gamma rays at different doses, ranging from 0 to 15 kGy, using a 60Co Gammacell 220 (AECL), dose rate about 2 kGy/h. After irradiation the viscosity was measured on the viscometer Brookfield model LV-DVIII at 50, 60 and 70 deg C within a period of 48h. Pectin viscosity with high degree of methoxylation decreased sharply with the radiation dose remaining almost constant from 10 kGy. Pectin with low degree of methoxylation presented initially higher values of viscosity and the radiation induced decrease was also pronounced. Viscosity measurements decreased with the increase of the temperature applied for both kind of samples. The effect of radiation induced chain breaks generation in pectin molecules was evident through the viscosity reduction of irradiated pectin solutions although the viscosity presented diverse values depending of the degree of methoxylation of carboxyl groups in the backbone of polysaccharide macromolecules. (author)

  6. Radiation sensitive area detection device and method

    Science.gov (United States)

    Carter, Daniel C. (Inventor); Hecht, Diana L. (Inventor); Witherow, William K. (Inventor)

    1991-01-01

    A radiation sensitive area detection device for use in conjunction with an X ray, ultraviolet or other radiation source is provided which comprises a phosphor containing film which releases a stored diffraction pattern image in response to incoming light or other electromagnetic wave. A light source such as a helium-neon laser, an optical fiber capable of directing light from the laser source onto the phosphor film and also capable of channelling the fluoresced light from the phosphor film to an integrating sphere which directs the light to a signal processing means including a light receiving means such as a photomultiplier tube. The signal processing means allows translation of the fluoresced light in order to detect the original pattern caused by the diffraction of the radiation by the original sample. The optical fiber is retained directly in front of the phosphor screen by a thin metal holder which moves up and down across the phosphor screen and which features a replaceable pinhole which allows easy adjustment of the resolution of the light projected onto the phosphor film. The device produces near real time images with high spatial resolution and without the distortion that accompanies prior art devices employing photomultiplier tubes. A method is also provided for carrying out radiation area detection using the device of the invention.

  7. High sensitive radiation detector for radiology dosimetry

    International Nuclear Information System (INIS)

    Fricke solution has a wide range of applications as radiation detector and dosimetry. It is particularly appreciated in terms of relevant comparative advantages, like tissue equivalence when prepared in aqueous media like gel matrix, continuous mapping capability, dose rate recorded and incident direction independence as well as linear dose response. This work presents the development and characterization of a novel Fricke gel system, based on modified chemical compositions making possible its application in clinical radiology. Properties of standard Fricke gel dosimeter for high dose levels are used as starting point and suitable chemical modifications are introduced and carefully investigated in order to attain high resolution for low dose ranges, like those corresponding to radiology interventions. The developed Fricke gel radiation dosimeter system achieves the expected typical dose dependency, actually showing linear response in the dose range from 20 up to 4000 mGy. Systematic investigations including several chemical compositions are carried out in order to obtain a good enough dosimeter response for low dose levels. A suitable composition among those studied is selected as a good candidate for low dose level radiation dosimetry consisting on a modified Fricke solution fixed to a gel matrix containing benzoic acid along with sulfuric acid, ferrous sulfate, xylenol orange and ultra-pure reactive grade water. Dosimeter samples are prepared in standard vials for its in phantom irradiation and further characterization by spectrophotometry measuring visible light transmission and absorbance before and after irradiation. Samples are irradiated by typical kV X-ray tubes and calibrated Farmer type ionization chamber is used as reference to measure dose rates inside phantoms in at vials locations. Once sensitive material composition is already optimized, dose-response curves show significant improvement regarding overall sensitivity for low dose levels. According to

  8. High sensitive radiation detector for radiology dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Valente, M.; Malano, F. [Instituto de Fisica Enrique Gaviola, Oficina 102 FaMAF - UNC, Av. Luis Medina Allende, Ciudad Universitaria, 5000 Cordoba (Argentina); Molina, W.; Vedelago, J., E-mail: valente@famac.unc.edu.ar [Laboratorio de Investigaciones e Instrumentacion en Fisica Aplicada a la Medicina e Imagenes por Rayos X, Laboratorio 448 FaMAF - UNC, Ciudad Universitaria, 5000 Cordoba (Argentina)

    2014-08-15

    Fricke solution has a wide range of applications as radiation detector and dosimetry. It is particularly appreciated in terms of relevant comparative advantages, like tissue equivalence when prepared in aqueous media like gel matrix, continuous mapping capability, dose rate recorded and incident direction independence as well as linear dose response. This work presents the development and characterization of a novel Fricke gel system, based on modified chemical compositions making possible its application in clinical radiology. Properties of standard Fricke gel dosimeter for high dose levels are used as starting point and suitable chemical modifications are introduced and carefully investigated in order to attain high resolution for low dose ranges, like those corresponding to radiology interventions. The developed Fricke gel radiation dosimeter system achieves the expected typical dose dependency, actually showing linear response in the dose range from 20 up to 4000 mGy. Systematic investigations including several chemical compositions are carried out in order to obtain a good enough dosimeter response for low dose levels. A suitable composition among those studied is selected as a good candidate for low dose level radiation dosimetry consisting on a modified Fricke solution fixed to a gel matrix containing benzoic acid along with sulfuric acid, ferrous sulfate, xylenol orange and ultra-pure reactive grade water. Dosimeter samples are prepared in standard vials for its in phantom irradiation and further characterization by spectrophotometry measuring visible light transmission and absorbance before and after irradiation. Samples are irradiated by typical kV X-ray tubes and calibrated Farmer type ionization chamber is used as reference to measure dose rates inside phantoms in at vials locations. Once sensitive material composition is already optimized, dose-response curves show significant improvement regarding overall sensitivity for low dose levels. According to

  9. Role of mitochondria in radiation sensitivity

    International Nuclear Information System (INIS)

    This paper describes mainly the role of mitochondrial (Mt) manganese superoxide dismutase (MnSOD) for deciding the radiation sensitivity of cells. The fact that Mt concerns with apoptosis has been shown by the finding that change in Mt membrane potential relates with the cell death. Mt has the electron transport system to yield the cellular energy molecule (ATP) and from which electrons are leaked out in 2-3%, a considerably large proportion in a cell. The electrons react with oxygen nearby to yield SO (O2·-), which in turn induces apoptosis through oxidation stress (OS). On the other hand, MnSOD is transported in Mt from cytoplasm and excludes the reactive oxygen species (ROS) like SO. Studies by MnSOD gene-deletion, knockout, cDNA-transfection, and transgenesis have indicated MnSOD is essential for keeping life and resistance to OS. Authors have shown that overexpression of Mt MnSOD protects against radiation-induced cell death, suggesting that Mt participates in radiation sensitivity where SO is involved. Interestingly, MnSOD activity is low in cancer cells, its overexpression results in tumor suppression and MnSOD is a target in leukemia therapy. When MTS (Mt targeting sequence, necessary for the enzyme to enter Mt)-deleted MnSOD is transfected, cells lack resistance to radiation, indicating the enzyme must be present in Mt. Mt DNA damage leading to electron transport system impairment is found to increase ROS, and to be reversed by the transfection of MnSOD gene. Studies of Mt DNA damage in cancer cells where aerobic glycolysis is actively operated, are currently in progress lively, and are thought to promote the development of diagnosis and treatment of cancer. (R.T.)

  10. Radiation-Sensitive Mutants of CAENORHABDITIS ELEGANS

    OpenAIRE

    Hartman, Philip S.; Herman, Robert K.

    1982-01-01

    Nine rad (for abnormal radiation sensitivity) mutants hypersensitive to ultraviolet light were isolated in the small nematode Caenorhabditis elegans. The mutations are recessive to their wild-type alleles, map to four of the six linkage groups in C. elegans and define nine new games named rad-1 through rad-9. Two of the mutants—rad-1 and rad-2—are very hypersensitive to X rays, and three—rad-2, rad-3 and rad-4—are hypersensitive to methyl methanesulfonate under particular conditions of exposu...

  11. Directionally Sensitive Silicon Radiation Sensor (VCELL)

    Science.gov (United States)

    Cook, Koy B.

    2002-01-01

    Sensors are a mission critical element in many NASA programs and require some very unique properties such as small size, low power, high reliability, low weight. Low cost sensors offer the possibility of technology transfer to the public domain for commercial applications. One sensor application that is important to many NASA programs is the ability to point at a radiation source, such as the sun. Such sensors may be an integral part of the guidance and control systems in space platforms and in remote exploratory vehicles. Sun/solar pointing is also important for ground-based systems such as solar arrays. These systems are not required to be small and lightweight. However, if a sensor with a sun pointing capability was developed that is very small, rugged, lightweight and at the same time low cost, it certainly could be used in existing and perhaps many new ground based applications, The objective of the VCELL (Directionally Sensitive Silicon Radiation Sensor) research is to develop a new and very unique silicon based directionally sensitive radiation sensor which can be fabricated using conventional monolithic IC technologies and which will meet the above requirements. The proposed sensor is a novel silicon chip that is directionally sensitive to incident radiation, providing azimuth and elevation information on the incident radiation. The resulting sensor chip will be appropriate for integration into a silicon IC or useful in a hybrid structure to be interfaced with a standard IEEE 1451 bus interface IC to create an Intelligent Sensor. It is presently estimated that it will require about three man-years of effort to complete the VCELL research and development. This includes the optical, electrical, mechanical and silicon fabrication and testing as well as computer simulations and theoretical analysis and modeling including testing in simulated space environments, This report summarizes the sensor research completed this summer as part of the Summer Faculty

  12. Stromal sensitivity to radiation and hyperthermia

    International Nuclear Information System (INIS)

    The influence on stroma of heat alone, X-rays alone or the combined treatment, has been studied using the tumour bed effect (TBE) as an assay. Ca NT cells have been implanted into previously treated subcutaneous sites as an angiogenic stimulus. The vascular damage is then assessed by the reduced tumour growth rate. A range of X-ray doses was used and large alterations in latent period for growth to 2 mm diameter were followed by smaller alterations in the growth rate of established tumours. A dose reponse relationship was seen for latency and for growth rate. A range of subcutaneous temperatures was obtained by immersion in a water bath for 60 minutes at 400 to 44.50C. A slight retardation of tumour growth was seen after 41.50C, but an unexpected acceleration resulted from 44.50C. Combined heat and X-ray treatments showed thermal sensitization of the X-ray induced TBE at 41.50C, with a reversal at higher temperatures. At 430C and 44.50C a mild thermal burn was induced and this appeared to elicit neovascularisation that could be utilized by the implanted tumour cells. Delayed implantation of tumour cells abolished this effect. (author)

  13. Development of a radiation-sensitive indicator

    International Nuclear Information System (INIS)

    A poly(vinyl alcohol) (PVA) film containing acid-sensitive dye (bromophenol red, BPR) and water soluble chlorine-containing substance [CCl3COONa or chloral hydrate (CCl3CH(OH)2, 2,2,2-trichloroethan-1,1-diol)] may be useful as a radiation-sensitive indicator. The acid-sensitive dye in the film changes its color from violet to pale yellow by irradiation due to the consequent lowering of the pH of the film caused by the HCl generated from the radiolysis of the Cl-containing substance. This film can be used as a dosimeter in a relatively low dose range up to 5 kGy. This response range makes this film useful in some food irradiation, pasteurization and water purification applications. The effects of temperature and relative humidity during irradiation and post-irradiation storage on the response of the film are discussed. It is inexpensive, does not require toxic solvents in preparation and easy to prepare in a laboratory. (author)

  14. Radiation sensitization by inhibition of activated ras

    International Nuclear Information System (INIS)

    Background and purpose: Ras has been identified as a significant contributor to radiation resistance. This article reviews preclinical and phase I clinical studies that reported on combining inhibition of activated Ras and downstream effectors of Ras with radiotherapy. Material and methods: transfection studies and RNA interference were used to check the role of the Ras isoforms for intrinsic radiation sensibility. Western blotting was used to control for prenylation inhibition of the respective Ras isoforms and for changes in activity of downstream proteins. Clonogenic assays with human and rodent tumor cell lines served for testing radiosensitivity. In vivo, farnesyltransferase inhibitors (FTIs) and irradiation were used to treat xenograft tumors. Ex vivo plating efficiency measurements, regrowth of tumors, and EF5 staining for detection of hypoxia were endpoints in these studies. Simultaneous treatment with L-778,123 and irradiation was performed in non-small cell lung cancer, head and neck cancer, and pancreatic cancer patients. Results: radiation sensitization was achieved in vitro and in vivo blocking the prenylation of Ras proteins in cell lines with Ras activated by mutations or receptor signaling. Among the many Ras downstream pathways the phosphoinositide 3 (PI3) kinase-Akt pathway was identified as a contributor to Ras-mediated radiation resistance. Furthermore, increased oxygenation was observed in xenograft tumors after FTI treatment. Combined treatment in a phase I study was safe and effective. Conclusion: the rational combination of FTIs with radiotherapy may improve the clinical results of patients with tumors who bear mutant or receptor-signaling activated Ras. (orig.)

  15. Gamma radiation sensitivity in Nigella sativa L

    International Nuclear Information System (INIS)

    Gamma irradiation induced mutagenic sensitivity of Nigella sativa L. (black cummin) was assessed from R1 attributes like frequency of seed germination, rate of seedling growth, chromosomal anomalies and sterility types, following exposures of dry dormant seed samples (1.8 % moisture content) to 5 KR, 10 KR, 20 KR, 30 KR, 40 KR, 50 KR and 60 KR of γ-irradiations. Results indicated that gamma radiations have induced both physiological and chromosomal disturbances. LD50 was found to lie between 20 KR and 30 KR of γ-ray. Treatments beyond 30 KR of irradiation were found to be lethal due to complete failure of emergence of seedlings in the field conditions; although 5 KR has shown stimulation in mitotic index. Sterility types have possibly appeared as an outcome of meiotic disturbances. (author)

  16. Adaptive radiation-induced epigenetic alterations mitigated by antioxidants

    OpenAIRE

    Bernal, Autumn J.; Dolinoy, Dana C; Huang, Dale; Skaar, David A.; Weinhouse, Caren; Jirtle, Randy L

    2013-01-01

    Humans are exposed to low-dose ionizing radiation (LDIR) from a number of environmental and medical sources. In addition to inducing genetic mutations, there is concern that LDIR may also alter the epigenome. Such heritable effects early in life can either be positively adaptive or result in the enhanced formation of diseases, including cancer, diabetes, and obesity. Herein, we show that LDIR significantly increased DNA methylation at the viable yellow agouti (Avy) locus in a sex-specific man...

  17. Radiation-induced motility alterations in medulloblastoma cells

    OpenAIRE

    Rieken, Stefan; Rieber, Juliane; Brons, Stephan; Habermehl, Daniel; Rief, Harald; Orschiedt, Lena; Lindel, Katja; Klaus J. Weber; Debus, Jürgen; Combs, Stephanie E

    2015-01-01

    Photon irradiation has been repeatedly suspected of increasing tumor cell motility and promoting locoregional recurrence of disease. This study was set up to analyse possible mechanisms underlying the potentially radiation-altered motility in medulloblastoma cells. Medulloblastoma cell lines D425 and Med8A were analyzed in migration and adhesion experiments with and without photon and carbon ion irradiation. Expression of integrins was determined by quantitative FACS analysis. Matrix metallop...

  18. Sensitiveness of viruses to gamma radiation

    International Nuclear Information System (INIS)

    The sensitiveness of viruses to gamma rays was compared using eight viruses suspended with low concentration in drinking water, and four viruses present in high concentrations in tissue culture medium. The results show that the following factors are responsible for the resistance of viruses to gamma rays: 1. type of virus: the specific radiation resistance varied considerably; in general, there was a closer correlation with the general resistance of the virus to chemico-physical influences than with the type of nucleic acid of the virus examined; 2. medium of suspension and state of aggregation: high protein content and lyophilisation increased the resistance to gamma rays widely; 3. virus concentration: the virus reduction by a factor of 10 in suspensions with high virus concentration needed a higher radiation dose compared with suspensions of low virus content. All the results demonstrate the kinetics of inactivation to be a 1st order reaction. The increase of temperature to 410C did not show any significant influence. (orig.)

  19. Comparative study of different surrogate markers for individual radiation sensitivity

    International Nuclear Information System (INIS)

    Radiotherapy is an important part of therapeutic tumor treatment concept. The applied total dose is limited by the unavoidable radiation effect on the surrounding normal tissue and the risk of radiation induced acute or chronic side effects. The clinical radiation sensitivity, i.e. the risk of radiogenic side effects is strongly coupled to the cellular radiation sensitivity. The contribution is focused on the development of a predictive tool for the individual radiation sensitivity for individual radiotherapeutic planning using lymphocytes. Residual foci, i.e. accumulated repair associated proteins at the residual double strand break are supposed to be surrogate markers of the cellular radiation sensitivity. No relation between the foci detection and the G(0)/G(1) was found assay with respect to the individual radiation sensitivity.

  20. Genetics of human sensitivity to ultraviolet radiation

    Science.gov (United States)

    Cleaver, James E.

    1994-07-01

    the major human health effects of solar and artificial UV light occur from the UVB and UVC wavelength ranges and involve a variety of short-term and long-term deleterious changes to the skin and eyes. the more important initial damage to cellular macromolecules involves dimerization of adjacent pyrimidines in DNA to produce cyclobutane pyrimidine dimes, (6-4) pyrimidine- pyrimidone, and (6-4) dewar photoproducts. these photoproducts can be repaired by a genetically regulated enzyme system (nucleotide excision repair) which removes oligonucleotides 29-30 nucleotides long that contain the photoproducts, and synthesizes replacement patches. At least a dozen gene products are involved in the process of recognizing photoproducts in DNA, altering local DNA helicity and cleaving the polynucleotide chain at defined positions either side of a photoproduct. Hereditary mutations in many of these genes are recognized in the human genetic disorders xeroderma pigmentosum (XP), Cockayne syndrome (CS), and trichothiodystrophy (TTD). Several of the gene products have other functions involving the regulation of gene transcription which accounts for the complex clinical presentation of repair deficient diseases that involve sensitivity of the skin and eyes to UV light, increased solar carcinogenesis (in XP), demyelination, and ganglial calcification (in CS), hair abnormalities (in TTD), and developmental and neurological abnormalities

  1. Metal-containing radiation-sensitive polymers

    International Nuclear Information System (INIS)

    The copolymers of methyl methacrylate with alkali metal salts (Na, K, and Cs) of methacrylic acid have been prepared by saponification K, and Cs) of methylacrylic acid have been prepared by saponification of the homopolymer poly(methyl methacrylate), PMMA. Low degrees of hydrolysis have been achieved by a heterogeneous system, and from the infrared spectra it has been confirmed that the ester groups of the methyl methacrylates are directly converted to the metal salts of methacrylic acid. These ionomers exhibit pseudo high molecular weights in gel permeation chromatogram, but no appreciable increase in intrinsic viscosities is observed in comparison to PMMA. The coordinated inorganic polymers poly[(dithio-2,2'-diacetato)bis(dimethylsulfoxide)dioxouranium(VI)] and poly[{methylenebis(thio)-2,2'-bis(acetato)}bis(dimethylsulfoxide)dioxouranium(VI)]have been synthesized in dimethyl sulfoxide solution with about 90% yield. The degree of polymerization and the number of average molecular weights of these polymers have been assessed by high resolution nuclear magnetic resonance, with which the acetato end group to the bridging ligand group ratios have been determined. The polymers bridging ligand group ratios have been determined. The polymers have been characterized by employing various techniques: infrared spectra, thermal gravimetric analysis, 13C solid state nuclear magnetic resonance, and gel permeation chromatography. The prepared polymer samples have been subjected to various doses of 137Cs gamma radiation under which the polymers predominantly undergo chain scission. The radiation sensitivities of the polymers are assessed by G values which are obtained from gel permeation chromatograms. These uranyl polymers exhibit unusually high G values

  2. Metal-containing radiation-sensitive polymers

    Energy Technology Data Exchange (ETDEWEB)

    Lee, A.Y.

    1986-01-01

    The copolymers of methyl methacrylate with alkali metal salts (Na, K, and Cs) of methacrylic acid have been prepared by saponification K, and Cs) of methylacrylic acid have been prepared by saponification of the homopolymer poly(methyl methacrylate), PMMA. Low degrees of hydrolysis have been achieved by a heterogeneous system, and from the infrared spectra it has been confirmed that the ester groups of the methyl methacrylates are directly converted to the metal salts of methacrylic acid. These ionomers exhibit pseudo high molecular weights in gel permeation chromatogram, but no appreciable increase in intrinsic viscosities is observed in comparison to PMMA. The coordinated inorganic polymers poly((dithio-2,2'-diacetato)bis(dimethylsulfoxide)dioxouranium(VI)) and poly()methylenebis(thio)-2,2'-bis(acetato))bis(dimethylsulfoxide)dioxouranium(VI))have been synthesized in dimethyl sulfoxide solution with about 90% yield. The degree of polymerization and the number of average molecular weights of these polymers have been assessed by high resolution nuclear magnetic resonance, with which the acetato end group to the bridging ligand group ratios have been determined. The polymers bridging ligand group ratios have been determined. The polymers have been characterized by employing various techniques: infrared spectra, thermal gravimetric analysis, /sup 13/C solid state nuclear magnetic resonance, and gel permeation chromatography. The prepared polymer samples have been subjected to various doses of /sup 137/Cs gamma radiation under which the polymers predominantly undergo chain scission. The radiation sensitivities of the polymers are assessed by G values which are obtained from gel permeation chromatograms. These uranyl polymers exhibit unusually high G values.

  3. Radiation sensitivity of adult human parenchymal hepatocytes

    International Nuclear Information System (INIS)

    The purpose of this study was to determine the radiosensitivity and repair kinetics of adult human parenchymal hepatocytes. Discarded viable human liver was obtained from the surgical pathology laboratory, and the cells were enzymatically isolated via a modification of the 2-step in situ collagenase perfusion technique used for the rat. The isolated hepatocytes were cultured with MEM media (10% FCS) in collagen coated 60 mm plates. Three hr after the cells were placed in culture, the media was changed to remove any dead unattached hepatocytes. After 24hr the viable hepatocytes were removed from the plates with collagenase and irradiated (40C, 21% O/sub 2/) with /sup 60/Co (1 Gy/min). The alkaline elution technique was used to quantify the single strand breaks (SSB). A linear dose response curve was obtained when the strand scission factor was plotted versus radiation dose and the slopes for the rat (4 cases) and human hepatocytes (6 cases) were 0.0302 and 0.0221 Gy/sup -1/, respectively. Thus, human hepatocytes are approximately 25% more radioresistant than those from the rat; this correlates with the GSH levels in the human hepatocytes (15 mM) being 20% greater than that in rat hepatocytes (12 mM). In contrast, the kinetics of repair of SSB in human hepatocytes was t/sub 1/2 fast/ = 20 min. t/sub 1/2 slow/ = 267 min) approximately 3 times slower than that in rat hepatocytes (t/sub 1/2 fast/ = 6 min, t/sub 1/2 slow/ = 98 min) and after 3 hr of repair the percent of the initial damage remaining was 20% and 15%, respectively. These date imply that in comparison to rat hepatocytes, human hepatocytes would be more radioresistant to large single doses, but equal if not more sensitive to fractionated radiation treatment

  4. Radiation sensitivity of hyperthermal composting microorganisms

    Science.gov (United States)

    Choi, Jong-Il; Yoon, Min-Chul; Kim, Jae-Hun; Yamashita, Masamichi; Kim, Geun Joong; Lee, Ju-Woon

    In the space station and vehicles designed for long human mission, high-temperature compost is a promising technology for decomposing organic waste and producing the fertilizers. In space, the microorganisms could have the changed biological activities or even be mutated by ionizing irradiation. Therefore, in this study, the effect of gamma irradiation on the sensitivity of bacteria in hyperthermal composting was investigated. The sequence analysis of the amplified 16s rDNA genes and amoA gene were used for the identification of composting microorganisms. Viability of microorganisms in compost soil after gamma irradiation was directly visualized with LIVE/DEAD Baclight viability kit. The dominant bacterial genera are Weissella cibaria and Leuconostoc sp. and fungus genera are Metschnikowia bicuspidate and Pichia guilliermondii, respectively. By the gamma irradiation up to the dose of 1 kGy, the microbial population was not changed. Also, the enzyme activities of amylase and cellulose were sustained by the gamma irradiation. These results show that these hyperthermia microorganisms might have the high resistance to gamma radiation and could be used for agriculture in the Space Station.

  5. Acetylene-sensitized radiation crosslinking of polytetrafluoroethylene

    International Nuclear Information System (INIS)

    The radiation crosslinking of polytetrafluoroethylene (PTFE) in the presence of acetylene under γ radiation (60Co) at a dose rate of 2 Gy/s up to absorbed doses of 20-60 kGy was studied. The yield of crosslinking was determined from thermomechanical testing data and, on this basis, it was concluded that crosslinking follows the chain mechanism. Radiation-crosslinked PTFE is shown to possess high wear resistance and enhanced radiation stability

  6. The effects of alterations in haematocrit on tumour sensitivity to X-rays

    International Nuclear Information System (INIS)

    The effect of acute and chronic changes in haematocrit on the radiosensitivity of three mouse tumours (EMT6, KHT and RIF-1) were studied. Alterations in haematocrit were achieved by bleeding followed by retransfusion. When radiation was preceded immediately by an acute reduction in haematocrit (anaemia), radiosensitivity was markedly reduced in each tumour. An acute rise in haematocrit (polycythaemia) increased or decreased X-ray sensitivity depending on its severity. The optimum haematocrit for maximum sensitivity was always found to be at a level 5-10%. When the time between induction of anaemia and irradiation was increased, simulating a progressively longer duration of anaemia, marked changes in radiosensitivity of all the tumours were observed. A short duration of anaemia resulted in a resistant tumour with each cell line, but the resistance was gradually lost as the anaemia was prolonged, even though no recovery in haematocrit occurred. The rate of recovery to normal radiosensitivity varied from 24 to 72 hours in the different tumours. Therefore, only haematocrit changes which occurred within 1-3 days of a dose of radiation affect the radiosensitivity of these tumours. (author)

  7. Radiation-induced motility alterations in medulloblastoma cells.

    Science.gov (United States)

    Rieken, Stefan; Rieber, Juliane; Brons, Stephan; Habermehl, Daniel; Rief, Harald; Orschiedt, Lena; Lindel, Katja; Weber, Klaus J; Debus, Jürgen; Combs, Stephanie E

    2015-05-01

    Photon irradiation has been repeatedly suspected of increasing tumor cell motility and promoting locoregional recurrence of disease. This study was set up to analyse possible mechanisms underlying the potentially radiation-altered motility in medulloblastoma cells. Medulloblastoma cell lines D425 and Med8A were analyzed in migration and adhesion experiments with and without photon and carbon ion irradiation. Expression of integrins was determined by quantitative FACS analysis. Matrix metalloproteinase concentrations within cell culture supernatants were investigated by enzyme-linked immunosorbent assay (ELISA). Statistical analysis was performed using Student's t-test. Both photon and carbon ion irradiation significantly reduced chemotactic medulloblastoma cell transmigration through 8-μm pore size membranes, while simultaneously increasing adherence to fibronectin- and collagen I- and IV-coated surfaces. Correspondingly, both photon and carbon ion irradiation downregulate soluble MMP9 concentrations, while upregulating cell surface expression of proadhesive extracellular matrix protein-binding integrin α5. The observed phenotype of radiation-altered motility is more pronounced following carbon ion than photon irradiation. Both photon and (even more so) carbon ion irradiation are effective in inhibiting medulloblastoma cell migration through downregulation of matrix metalloproteinase 9 and upregulation of proadhesive cell surface integrin α5, which lead to increased cell adherence to extracellular matrix proteins. PMID:25736470

  8. Radiation-induced motility alterations in medulloblastoma cells

    International Nuclear Information System (INIS)

    Photon irradiation has been repeatedly suspected of increasing tumor cell motility and promoting locoregional recurrence of disease. This study was set up to analyse possible mechanisms underlying the potentially radiation-altered motility in medulloblastoma cells. Medulloblastoma cell lines D425 and Med8A were analyzed in migration and adhesion experiments with and without photon and carbon ion irradiation. Expression of integrins was determined by quantitative FACS analysis. Matrix metalloproteinase concentrations within cell culture supernatants were investigated by enzyme-linked immunosorbent assay (ELISA). Statistical analysis was performed using Student's t-test. Both photon and carbon ion irradiation significantly reduced chemotactic medulloblastoma cell transmigration through 8-μm pore size membranes, while simultaneously increasing adherence to fibronectin- and collagen I- and IV-coated surfaces. Correspondingly, both photon and carbon ion irradiation downregulate soluble MMP9 concentrations, while upregulating cell surface expression of proadhesive extracellular matrix protein-binding integrin α5. The observed phenotype of radiation-altered motility is more pronounced following carbon ion than photon irradiation. Both photon and (even more so) carbon ion irradiation are effective in inhibiting medulloblastoma cell migration through downregulation of matrix metalloproteinase 9 and upregulation of proadhesive cell surface integrin α5, which lead to increased cell adherence to extracellular matrix proteins. (author)

  9. Sensitivity of transient synchrotron radiation to tokamak plasma parameters

    Energy Technology Data Exchange (ETDEWEB)

    Fisch, N.J.; Kritz, A.H.

    1988-12-01

    Synchrotron radiation from a hot plasma can inform on certain plasma parameters. The dependence on plasma parameters is particularly sensitive for the transient radiation response to a brief, deliberate, perturbation of hot plasma electrons. We investigate how such a radiation response can be used to diagnose a variety of plasma parameters in a tokamak. 18 refs., 13 figs.

  10. Relative radiation sensitivity of insulators, stabilizers, and superconductors

    International Nuclear Information System (INIS)

    The objective of this work was to compare the radiation sensitivity of the various parts of superconducting magnet systems. Using the radiation spectra calculated by Engholm for the Engineering Test Facility (ETF) toroidal field magnet inboard leg and available data on radiation effects, commonly used magnet components were ranked in order of radiation sensitivity. It was found that epoxy-based insulators and copper and aluminum stabilizers were the most sensitive parts of the magnets, more sensitive than the superconductors. Use of polyimide-based insulators would make the insulators less vulnerable than the stabilizers and superconductors. An experiment is planned to study the effects of various degrees of cold work on the radiation-induced magnetoresistance of copper, since this will be an important factor for fusion magnet stabilizers

  11. Alterations induced in Escherichia Coli cells by gamma radiation

    International Nuclear Information System (INIS)

    Modifications occurred in Escherichia coli cells exposed to gamma radiation (60Co source) were investigated. The irradiations were done at the LIN-COPPE laboratory of the UFRJ and the analysis at the Biology Department of the UTFPR. The E. coli cells were irradiated with 30, 60, 90, 120, 150, 180, 210, 240, 300, 480, 600 e 750 Gy doses. The samples were analyzed with Gram-stain, biochemical tests in EPM, MIO and Lysine Broth, Simmons Cytrate Medium and Rhamnose Broth, antibiogram and isolation of auxotrophic mutants. It was observed that for the received doses the E. coli did not show morphological alterations in the tests. Some E. Coli cells showed to be able to deaminade the L-tryptophan or they changed their sensibility for amoxillin and cephaloonine after the irradiation. The existence of aauxotrophic mutants after irradiation was also verified. (author)

  12. Ionizing radiation and bacterial challenge alter splenic cytokine gene expression

    International Nuclear Information System (INIS)

    Irradiation increases susceptibility to bacterial infection. Exogenous proinflammatory cytokines can alter the response of mice to γradiation, but the role of endogenous inflammatory cytokines after bacterial infection in irradiated animals is not known. Gene expression of hematopoietic (GM-CSF) and proinflammatory (IL-1β, IL-6 and TNF-α) cytokines were examined in spleens of B6D2F1/J female mice after irradiation alone (1.0- and 7.0-Gy), and after irradiation followed by Klebsiella pneumoniae s.c. challenge 4 days postirradiation by using the reverse transcription-polymerase chain reaction (RT-PCR) and Southern blot hybridization. At 4, 8, and 24 h after bacterial challenge in 7.0-Gy-irradiated mice, GM-CSF mRNA increased (p<0.05). TNF-α mRNA in irradiated mice were slightly decreased, whereas after bacterial challenge, TNF-α mRNA elevated at 30 h in 7.0-Gy-irradiated mice; at 4, and 8 h in 1.0-Gy-irradiated mice, and at 1 h in sham-irradiated mice (p<0.05). IL-6 mRNA displayed a biphasic response in 7.0-Gy-irradiated mice, and, after bacterial challenge, in both irradiated mice (1.0- and 7.0-Gy) and sham-irradiated mice. IL-1β mRNA remained at or below normal for 8 h and increased at 24 h after bacterial challenge on day 4 in 7.0-Gy-irradiated mice. These results indicate that sublethal gamma radiation alters the patterns of the hematopoietic and proinflammatory cytokine responses to bacterial challenge in vivo. Consequently, treatment protocols may need to take into account changes in cytokine gene responses to resolve infection after irradiation. (author)

  13. High sensitivity radiation detector for capillary electrophoresis

    International Nuclear Information System (INIS)

    Capillary electrophoresis is an important new instrumental technique capable of high resolution separation and analysis of small quantities of nucleotides, amino acids, peptides, and proteins with very high efficiency and throughput. The unprecedented sensitivity of this technique will be useful for such new applications as in vivo labeling and identification of trace substances and single cell work. The principle limitation of this technique for radiolabeled molecules has been identified as the sensitivity of the detector, primarily due to the small sample volume (32P-labeled biomolecules with unprecedented sensitivity. This detector can be easily retrofitted into existing CE apparatus

  14. Potential for radiation sensitizers and possible strategy for use

    International Nuclear Information System (INIS)

    The search for radiation sensitizers for use in radiotherapy is based on the assumption that proper use of these compounds will provide a differential sensitization of tumor and normal tissue. Based on the evidence that hypoxic cells exist within human tumors but not within normal cell populations, there is reason to believe that specific sensitizers of hypoxic cells might provide useful therapeutic benefit. This paper discusses the possible advantages of such sensitizers, over reliance on the phenomenon of reoxygenation, and describes very briefly the current status of hypoxic cell sensitizers. Finally a proposal is made concerning the way in which such sensitizers might be tested for their efficacy in human radiotherapy

  15. Genomic alterations in radiation-induced murine acute myeloid leukemias

    International Nuclear Information System (INIS)

    High-dose radiation induces acute myeloid leukemia (AML) in C3H mice, most of which have a high frequent hemizygous deletion around the D2Mit15 marker on the interstitially deleted region of chromosome 2. This region involves PU.1 (Sfpi-1), which is a critical candidate gene for initiation of mouse leukemogenesis. To identify other genes contributing to leukemogenesis with PU.1, we analyzed chromosomal aberrations and changes of expression in 18 AML-related genes in 39 AMLs. Array CGH analysis revealed that 35 out of 39 AMLs had hemizygous deletions of chromosome 2, and recurrent aberrations on chromosomes 4, 6, 8, 10, 11, 12, 15, and 18. Expressions of 18 AML-related genes, within the altered chromosome regions detected by array CGH were analyzed by using RT-PCR and/or real-time PCR. Although Wnt5b, Wnt16, G-CSFR, M-CSFR, SCL/Tal-1 and GATA1 genes were down-regulated, the c-myc gene was, on the contrary, up-regulated. Expression levels of two genes, Rasgrp1 and Wt1, within the deleted region of chromosome 2 correlated with the loss of one of two alleles, although the expression of PU.1 showed an inverse correlation. In addition, the expression level of PU.1 appeared to be higher with a coincidental missense point mutation in DNA-binding domain of PU.1 in the remaining allele, suggesting a feedback transcription control on PU.1. Such an autoregulation might be relevant to the fact that PU.1 haploinsufficiency per se triggers radiation-induced AML. Together with the detection of chromosomal aberrations, these findings provide useful clues to identify cooperative genes that are responsible for molecular pathogenesis of AMLs induced by low-dose-rate radiation exposure. (author)

  16. On the instability effects in radiation-sensitive chalcogenide glasses

    Energy Technology Data Exchange (ETDEWEB)

    Balitska, V. [Lviv State University for Vital Activity Safety, 35 Kleparivska str., Lviv, UA-79007 (Ukraine); Lviv Institute of Materials of SRC ' Carat' , 202 Stryjska str., Lviv, UA-79031 (Ukraine); Kovalskiy, A. [Lviv Institute of Materials of SRC ' Carat' , 202 Stryjska str., Lviv, UA-79031 (Ukraine); International Materials Institute for New Functionality in Glass, Lehigh University, 5 East Packer Avenue, Bethlehem, PA 18015-3195 (United States); Shpotyuk, O. [Lviv Institute of Materials of SRC ' Carat' , 202 Stryjska str., Lviv, UA-79031 (Ukraine); International Materials Institute for New Functionality in Glass, Lehigh University, 5 East Packer Avenue, Bethlehem, PA 18015-3195 (United States)], E-mail: shpotyuk@novas.lviv.ua; Vakiv, M. [Lviv Institute of Materials of SRC ' Carat' , 202 Stryjska str., Lviv, UA-79031 (Ukraine)

    2007-04-15

    The features of application of radiation-sensitive media based on chalcogenide glasses of As-Ge-S system for registration of high-energy {gamma}-radiation are analysed. It is shown that compositional features of the observed time-instability effect should be taken into account in order to ensure a higher accuracy of the developed dosimeters.

  17. On the instability effects in radiation-sensitive chalcogenide glasses

    International Nuclear Information System (INIS)

    The features of application of radiation-sensitive media based on chalcogenide glasses of As-Ge-S system for registration of high-energy γ-radiation are analysed. It is shown that compositional features of the observed time-instability effect should be taken into account in order to ensure a higher accuracy of the developed dosimeters

  18. The Visualization of Infrared Radiation Using Thermal Sensitive Foils

    Science.gov (United States)

    Bochnícek, Zdenek

    2013-01-01

    This paper describes a set of demonstration school experiments where infrared radiation is detected using thermal sensitive foils. The possibility of using standard glass lenses for infrared imaging is discussed in detail. It is shown that with optic components made from glass, infrared radiation up to 2.5 µm of wavelength can be detected. The…

  19. Sensitivity of viruses to radiation sterilization

    International Nuclear Information System (INIS)

    The hazard of infectious disease transmission with tissue allografts is a major concern in tissue banking practice. Microorganisms can be introduced into grafts during tissue collection, processing and storage, but even when all these procedures are performed under a septic conditions, the possibility of fungal, bacterial or viral disease transmission of donor origin can not be excluded. Therefore, in order to minimize the risk of infectious disease transmission, several steps should be undertaken, including a careful donor screening, proper tissue processing and sterilization of tissue allografts. The risk of transmission of viral infections such as hepatitis B, C, other viruses and particularly HIV with tissue allografts is of great significance and the search for sterilizing methods which inactivate and/or highly reduce viral infectivity continues. Sterilization of tissue allografts with ionizing radiation (introduced in the mid of 1950s) is increasingly used in tissue banking practice. The effectiveness of the radiation-sterilization procedure depends on the amount of energy transferred, the number of contaminating microorganisms and their resistance to ionizing radiation (initial contamination, bioburden). Usually, spores are more resistant than vegetative forms of bacteria, some fungi may be as resistant as bacterial spores, and viruses are, in general, more resistant than bacteria. Dita concerning effectiveness of ionizing radiation to inactivate viruses (e.g. such as HBV, HCV or HIV) in tissue allografts collected from cadavers are scarce. It has been found that the dose of irradiation needed to reduce HIV load by I log10 unit (D10) is about 4.0 kGy or even 5.6 kGy. The level of infectious HIV in plasma is usually evaluated by titration of tissue culture infective dose (TCID50/ml). Taking into consideration the recommended sterility assurance level (SAL) 10-6, assuming the HIV bioburden to be 103 TCID50/ml for the state of acute infection and D10 value of 4

  20. Polyploidy in aspen alters plant physiology and drought sensitivity

    Science.gov (United States)

    Greer, B.; Still, C. J.; Brooks, J. R.; Meinzer, F. C.

    2015-12-01

    Polyploids of quaking aspen (Populus tremuloides) may be better suited to dry climatic conditions than diploids. However, the expression of diploid and polyploid functional traits, including water use efficiency, an important component of drought avoidance and tolerance, are not well understood in quaking aspen. In this study diploid and triploid aspen clones' leaf, ramet, and stand functional traits were measured near the Rocky Mountain Biological Laboratory in Gothic, Colorado. The physiology of diploid and triploid aspen, including leaf size, chlorophyll content, stomatal size and density and stomatal conductance, as well as growth rates and carbon isotope discrimination in response to climate (measured in tree rings), were found to be significantly different between ploidy levels. These findings demonstrate different sensitivities of diploid and triploid clones to drought related climate stressors which may impact strategies for aspen forest management and conservation.

  1. Effect of troglitazone on radiation sensitivity in cervix cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    An, Zheng Zhe; Liu, Xian Guang; Song, Hye Jin; Choi, Chi Hwan; Kim, Won Dong; Park, Woo Yoon [Chungbuk National University College of Medicine, Cheongju (Korea, Republic of); Yu, Jae Ran [Konkuk University College of Medicine, Chungju (Korea, Republic of)

    2012-06-15

    Troglitazone (TRO) is a peroxisome proliferator-activated receptor {gamma} (PPAR{gamma} ) agonist. TRO has antiproliferative activity on many kinds of cancer cells via G1 arrest. TRO also increases Cu{sup 2+}/Zn{sup 2+} -superoxide dismutase (CuZnSOD) and catalase. Cell cycle, and SOD and catalase may affect on radiation sensitivity. We investigated the effect of TRO on radiation sensitivity in cancer cells in vitro. Three human cervix cancer cell lines (HeLa, Me180, and SiHa) were used. The protein expressions of SOD and catalase, and catalase activities were measured at 2-10 {mu}M of TRO for 24 hours. Cell cycle was evaluated with flow cytometry. Reactive oxygen species (ROS) was measured using 2',7'-dichlorofluorescin diacetate. Cell survival by radiation was measured with clonogenic assay. By 5 {mu}M TRO for 24 hours, the mRNA, protein expression and activity of catalase were increased in all three cell lines. G0- G1 phase cells were increased in HeLa and Me180 by 5 {mu}M TRO for 24 hours, but those were not increased in SiHa. By pretreatment with 5 {mu}M TRO radiation sensitivity was increased in HeLa and Me180, but it was decreased in SiHa. In Me180, with 2 {mu}M TRO which increased catalase but not increased G0-G1 cells, radiosensitization was not observed. ROS produced by radiation was decreased with TRO. TRO increases radiation sensitivity through G0-G1 arrest or decreases radiation sensitivity through catalasemediated ROS scavenging according to TRO dose or cell types. The change of radiation sensitivity by combined with TRO is not dependent on the PPAR {gamma} expression level.

  2. Guide for use of radiation-sensitive indicators. 2. ed.

    International Nuclear Information System (INIS)

    This guide covers the use of radiation-sensitive indicators in radiation processing. These indicators may be labels, papers, inks or packaging materials which undergo a color change or become colored when exposed to ionizing radiation. The purpose of these indicators is to determine visually whether or not a product has been irradiated, rather than to measure different dose levels. Such materials are not dosimeters and should not be used as a substitute for proper dosimetry. Information about dosimetry systems for ionizing radiation is provided in other ASTM and ISO/ASTM documents (see ISO/ASTM Guide 51261

  3. Characterization of UV radiation sensitive frog cell lines

    International Nuclear Information System (INIS)

    Twenty-one subclones of nine frog cell isolates were tested for sensitivity to a panel of DNA damaging agents. Two clones were identified which had a greater than wild type level of sensitivity to UV radiation but had a wild type level of sensitivity to the other agents. These clones were the haploid RRP602-7 and the diploid RRP802-1. RRP802-1 was found to be unstable with respect to UV sensitivity. The line was cloned in order to isolate stable sensitive and wild type derivatives. RRP802-1-16, a UV sensitive clone and RRP802-1-13, a clone with a wild type level of sensitivity to UV radiation, were isolated. The UV radiation sensitivity of RRP602-7, RRP802-1 and RRP802-1-16 did not correlate with cell size, cell shape, cell cycle distribution or ploidy. The cell cycle distribution after UV irradiation, the rate of DNA synthesis after UV-irradiation, the DNA polymerase α activity and the sister chromatid exchange frequency were all measured in RRP602-7, RRP802-1 and RRP802-1-16 in order to examine the DNA repair capacity. The presence of DNA repair pathways was examined directly in RRP602-7, RRP802-1 and RRP802-1-16. All were found to be proficient in photo-reactivation repair and postreplication repair of UV elicited DNA damage

  4. Radiation sensitization studies by silymarin on HCT-15 cells

    International Nuclear Information System (INIS)

    Radiotherapy has been widely used for treatment of human cancers. However, cancer cells develop radioresistant phenotypes following multiple exposures to the treatment agent that decrease the efficacy of radiotherapy. Here it was investigated that the radiation sensitization effects of silymarin found in colon cancer. The aim of this study was to investigate mechanisms involved in radiation sensitization growth inhibitory effect of silymarin in combination with radiation, in Human colon carcinoma (HCT-15). The human colon carcinoma was utilized and SRB-assay was performed to study anti-proliferative effect of silymarin in combination with gamma radiation (2 Gy) appropriate radiation dose was optimized and confirmed by clonogenic assay. Microscopic analysis was done by staining with Hoechst-33342, DAPI, Propidium iodide to confirm the presence of apoptosis. Nitric oxide production, changes in lipid peroxidation, Cell cycle analysis were carried out and mitochondrial membrane potential was measured by uptake of cationic dye JC-1 by using flow cytometer. Silymarin in combination with radiation (2 Gy) inhibited 70% ± 5% population growth of HCT-15 cells in time and dose dependent manner. Pre treatment of cells with silymarin for 30 min before radiation was found to be most effective for radiation sensitization. There was 25% increase in levels of nitric oxide as compare to control, whereas 2.5 fold change in lipid peroxidation with respect to control. IR-induced apoptosis in HCT-15 cell line was significantly enhanced by silymarin, as reflected by viability, DNA fragmentation, and mitochondrial dysfunction. Additionally, silymarin in combination with IR is found to be effective in sensitization of HCT-15 cells. In vivo studies on development of tumor and sensitization aspects needs to done in future. (author)

  5. Radiation sensitive devices and systems for detection of radioactive materials and related methods

    Energy Technology Data Exchange (ETDEWEB)

    Kotter, Dale K

    2014-12-02

    Radiation sensitive devices include a substrate comprising a radiation sensitive material and a plurality of resonance elements coupled to the substrate. Each resonance element is configured to resonate responsive to non-ionizing incident radiation. Systems for detecting radiation from a special nuclear material include a radiation sensitive device and a sensor located remotely from the radiation sensitive device and configured to measure an output signal from the radiation sensitive device. In such systems, the radiation sensitive device includes a radiation sensitive material and a plurality of resonance elements positioned on the radiation sensitive material. Methods for detecting a presence of a special nuclear material include positioning a radiation sensitive device in a location where special nuclear materials are to be detected and remotely interrogating the radiation sensitive device with a sensor.

  6. Multipurpose High Sensitivity Radiation Detector: Terradex

    International Nuclear Information System (INIS)

    Terradex project aims to realise an accurate and programmable multiparametric tool which will measure relevant physical quantities such as observation time, energy and type of all decay products of three naturally occurring decay chains of uranium and thorium series present in nature as well as the decay products of man-made radioactivity. The measurements described in this work are based on the performance tests of the first version of an instrument that is designed to provide high counting accuracy, by introducing self-triggering, delayed time-coincidence technique, of products of a given decay chain. In order to qualify the technique and to calibrate the Terradex, a 222Rn source is used. The continuous and accurate monitoring of radon concentration in air is realised by observing the alpha and beta particles produced by the decay of 222Rn and its daughters and tag each of them with a precise occurrence time. The validity of delayed coincident technique by using the state of the art electronics with application of novel data sampling and analysis methods are discussed. The flexibility of sampling protocols and the advantages of online calibration capability to achieve the highest level of precision in natural and man-made radiation measurements are also described

  7. Multipurpose High Sensitivity Radiation Detector: Terradex

    Energy Technology Data Exchange (ETDEWEB)

    Alpat, Behcet [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy)]. E-mail: behcet.alpat@pg.infn.it; Aisa, Damiano [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Bizzarri, Marco [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Blasko, Sandor [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Esposito, Gennaro [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Farnesini, Lucio [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Fiori, Emmanuel [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Papi, Andrea [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Postolache, Vasile [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Renzi, Francesca [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Ionica, Romeo [Politecnica University of Bucarest, Splaiul Indipendentei, Bucharest (Romania); Manolescu, Florentina [Space Science Institute of Bucharest, Maugurele, Bucharest (Romania); Ozkorucuklu, Suat [Suleyman Demirel Universitesi, Isparta (Turkey); Denizli, Haluk [Abant Izzet Baysal Universitesi, Bolu (Turkey); Tapan, Ilhan [Uludag Universitesi, Bursa (Turkey); Ercan Pilicer [Uludag Universitesi, Bursa (Turkey); Egidi, Felice [SITE Technology, Carsoli (Italy); Moretti, Cesare [SITE Technology, Carsoli(AQ) (Italy); Dicola, Luca [SITE Technology, Carsoli(AQ) (Italy)

    2007-05-11

    Terradex project aims to realise an accurate and programmable multiparametric tool which will measure relevant physical quantities such as observation time, energy and type of all decay products of three naturally occurring decay chains of uranium and thorium series present in nature as well as the decay products of man-made radioactivity. The measurements described in this work are based on the performance tests of the first version of an instrument that is designed to provide high counting accuracy, by introducing self-triggering, delayed time-coincidence technique, of products of a given decay chain. In order to qualify the technique and to calibrate the Terradex, a {sup 222}Rn source is used. The continuous and accurate monitoring of radon concentration in air is realised by observing the alpha and beta particles produced by the decay of {sup 222}Rn and its daughters and tag each of them with a precise occurrence time. The validity of delayed coincident technique by using the state of the art electronics with application of novel data sampling and analysis methods are discussed. The flexibility of sampling protocols and the advantages of online calibration capability to achieve the highest level of precision in natural and man-made radiation measurements are also described.

  8. Radiation sensitivity of food decay fungi

    International Nuclear Information System (INIS)

    Five species of food decay fungi, Aspergillus flavus, Asp. uiger, Penicillium sp., Botrytis cinerea and Rhizopus stolonifer, were examined for their radiosensitivity in several suspension media. Asp. flavus, Asp. niger and Penicillium sp. have almost the same sensitivity toward gamma rays, with D value in the range of 30 to 35 K rad, whereas Botrytis cinerea has a D value of approximately 55 K rad and Rhizopus stolonifer, the most resistant fungus studied, has a D value of approximately 100 K rad. Dry spores of Asp. flavus showed a considerable increase in their radioresistance when compared with spores irradiated in water. Asp. flavus and Penicillium sp. spores irradiated in citrate buffer at pH 3-7 showed almost no change in their radiosensitivity with pH, but Botrytis cinerea spores showed a distinct decrease in their radioresistance at pH 6 and 7. Penicillium sp. spores irradiated in sucrose solutions showed no significant change in their radioresistance. Botrytis cinerea spores displayed a higher radioresistance when they were irradiated in sucrose solution than in water. (author)

  9. Radiation and cadmium induced histological alteration in the mice liver

    International Nuclear Information System (INIS)

    radiation and cadmium induced changes at histological level. Alterations in the histological changes were found dose dependent. More pronounced histopathological changes were registered after the combined exposure of cadmium chloride and gamma rays. (author)

  10. Radiation vulcanization of natural rubber latex sensitized with commercial gases

    International Nuclear Information System (INIS)

    The industrial activities using natural rubber latex are fully compatible with rural areas in Amazon and other places in Brazil, as well as in other tropical countries. However the classical sulfur vulcanization presents many occupational problems for the workers in rural areas. Radiation vulcanization of natural rubber latex is a much more friendly process as sulfur compounds are not needed for crosslinking, although chemicals as acrylate monomers, particularly multifunctional acrylates are still used as sensitizers for radiation processes. Two commercial gases, acetylene and butadiene, were selected as sensitizers for the radiation vulcanization of natural rubber latex instead of acrylates. These gases accelerate the crosslinking rates of the cure process and lower the radiation dose required to achieve vulcanization of natural rubber latex and improve the mechanical properties to reduce the tackiness of rubber goods. (author)

  11. Radiation sensitivity as a genetic factor in carcinogenesis

    International Nuclear Information System (INIS)

    It is known that some association exists between cancer-prone hereditary diseases and radiation sensitivity. In the case of ataxia telagiectasia (AT), frequencies of ionizing radiation-induced mutations are believed to be lower in AT fibroblast cells than in normal cells. When employing lymphoblastoid cells, the AT cells exhibited the same gamma-ray-induced mutation rates in proportion to doses as the normal cells. Nevertheless, it is concluded that the AT cells do not exhibit induced mutations so readily as the normal cells, taking high sensitivity of AT cells to gamma-rays into account. This conclusion has led to concern about the relationship between carcinogenesis and mutation. To elucidate this, quantitative studies on mutation of oncogenes are required. It is also pointed out that the mechanism of cancer-prone hereditary diseases is uncertain. High sensitivity of the cells to certain mutagens does not necessarily reflect deficiency in damage repair, suggesting the possibility that there might be no association between carcinogenesis and high sensitivity to ionizing radiation. It remains to be elucidated whether DNA repair is involved in radiation sensitivity in the case of cancer-prone hereditary diseases including AT, except for the case of xeroderma pigmentosum. (Namekawa, K.)

  12. Radiation noise in a high sensitivity star sensor

    Science.gov (United States)

    Parkinson, J. B.; Gordon, E.

    1972-01-01

    An extremely accurate attitude determination was developed for space applications. This system uses a high sensitivity star sensor in which the photomultiplier tube is subject to noise generated by space radiations. The space radiation induced noise arises from trapped electrons, solar protons and other ionizing radiations, as well as from dim star background. The solar activity and hence the electron and proton environments are predicted through the end of the twentieth century. The available data for the response of the phototube to proton, electron, gamma ray, and bremsstrahlung radiations are reviewed and new experimental data is presented. A simulation was developed which represents the characteristics of the effect of radiations on the star sensor, including the non-stationarity of the backgrounds.

  13. Radiation-sensitive genetically susceptible pediatric sub-populations

    Energy Technology Data Exchange (ETDEWEB)

    Kleinerman, Ruth A. [National Cancer Institute, NIH, DHHS, Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, Rockville, MD (United States)

    2009-02-15

    Major advances in pediatric cancer treatment have resulted in substantial improvements in survival. However, concern has emerged about the late effects of cancer therapy, especially radiation-related second cancers. Studies of childhood cancer patients with inherited cancer syndromes can provide insights into the interaction between radiation and genetic susceptibility to multiple cancers. Children with retinoblastoma (Rb), neurofibromatosis type 1 (NF1), Li-Fraumeni syndrome (LFS), and nevoid basal cell carcinoma syndrome (NBCCS) are at substantial risk of developing radiation-related second and third cancers. A radiation dose-response for bone and soft-tissue sarcomas has been observed in hereditary Rb patients, with many of these cancers occurring in the radiation field. Studies of NF1 patients irradiated for optic pathway gliomas have reported increased risks of developing another cancer associated with radiotherapy. High relative risks for second and third cancers were observed for a cohort of 200 LFS family members, especially children, possibly related to radiotherapy. Children with NBCCS are very sensitive to radiation and develop multiple basal cell cancers in irradiated areas. Clinicians following these patients should be aware of their increased genetic susceptibility to multiple primary malignancies enhanced by sensitivity to ionizing radiation. (orig.)

  14. Radiation sensitivity of pine wood nematodes in woodchips

    International Nuclear Information System (INIS)

    The radiation sensitivity of pine wood nematodes has been tested over a range of dose values with a cesium-137 irradiator. Lethal doses were found to lie in a range above 6-8 kGy, too high to make this an economically attractive means of deinfestation for commercial woodchips. (author)

  15. Bio-molecular alterations induced by a chemical or radiating stress in isolated human cells

    International Nuclear Information System (INIS)

    After having recalled some aspects of radiobiology (effects of ionizing radiations, molecular targets of radiations, cellular responses with respect to the radiation), the author discusses various aspects of radio-sensitivity: intrinsic radio-sensitivity of tumoral and normal cells, DNA injuries and in vitro radio-sensitivity, genes of susceptibility to ionizing radiations, clustered injuries. Then she reports investigations performed by infrared micro-spectroscopy: characterization of pathological lines, of biological processes, of oxidative injuries induced by xenobiotics, of injuries induced by ionizing radiations

  16. Alteration of Bacterial Antibiotic Sensitivity After Short-Term Exposure to Diagnostic Ultrasound

    Science.gov (United States)

    Mortazavi, Seyed Mohammad Javad; Darvish, Leili; Abounajmi, Mohammad; Zarei, Samira; Zare, Tahereh; Taheri, Mohammad; Nematollahi, Samaneh

    2015-01-01

    Background Many pathogenic bacteria show different levels of antibiotic resistance. Furthermore, a lot of hospital-acquired infections are caused by highly resistant or multidrug-resistant Gram-negative bacteria. According to WHO, patients with drug-resistant infections have higher morbidity and mortality. Moreover, patients infected with bacteria that are resistant to antibiotics considerably consume more healthcare resources. Objectives In this study, we explored a physical method of converting drug-resistant bacteria to drug-sensitive ones. Materials and Methods This is an in vitro case-control study, performed at the Ionizing and Non-ionizing Radiation Protection Research Center (INIRPRC), Shiraz University of Medical Sciences (SUMS), Shiraz, Iran in 2014. All experiments were carried out using Gram-negative bacteria Klebsiella pneumonia and E. coli and Gram-positive Staphylococcus aureus and Streptococcus group A, isolated from hospitalized patients. The bacterial strains were obtained from the Persian Type Culture Collection, IROST, Iran (Klebsiella pneumonia PTCC 1290) and Bacteriology Department of Shahid Faghihi Teaching Hospital, Shiraz, Iran (E. coli, Staphylococcus aureus, and Streptococcus group A). The bacteria in culture plates were exposed to diagnostic ultrasound using a MyLab70XVG sonography system for 5 minutes. Then, the bacteria were cultured on Mueller-Hinton agar and incubated at 35°C for 18 hours. Finally, antibiotic susceptibility test was performed and the inhibition zone in both control and exposed groups were measured. Three replicate agar plates were used for each test and the inhibition zones of the plates were recorded. Results Compared with the results obtained from unexposed bacteria, statistically significant variations of sensitivity to antibiotics were found in some strains after short-term exposure. In particular, we found major differences (making antibiotic-resistant bacteria susceptible or vice versa) in the diameters of

  17. Alteration of the digestive motility linked with radiation-induced inflammatory processes in rats

    International Nuclear Information System (INIS)

    Exposure to ionizing radiation, whether accidental or for medical reasons, may lead to gastro-intestinal injury, characterized by nausea, vomiting, diarrhea and abdominal cramps. The aetiology of radiation-induced diarrhea remains to date unclear. In this study, we have investigated the acute effects of a 10 Gy abdominal irradiation on rat digestive functions. The objective of the first study was to evaluate the role of sensory afferent neurons, capsaicin-sensitive, on morphological changes and the inflammatory response following exposure. Three days after irradiation, we observed an inflammatory response characterized by neutrophils infiltration and mast cells de-granulation. No effect of capsaicin pre-treatment was seen on these parameters. However, neutrophils infiltration was increased as early as one day after irradiation in capsaicin-treated rats. No difference in severity of diarrhea was observed after denervation nor in morphological changes. These data demonstrate that abdominal irradiation results in diarrhea concomitant with an inflammatory response, and that sensory innervation does not play a major protective role. The objective of the rest of the work was in the first instance to characterize radiation-induced alterations of intestinal and colonic motility leading to diarrhea and secondly to evaluate the role of serotonin in such disorders. Perturbations in intestinal (MMC) and colonic (LSB) motor profiles were observed from the first day onwards. Migrating motor complexes (MMC) were completely disrupted at three days at the same time as the onset of diarrhea. In addition to inhibition of LSB, colonic fluid absorptive capacity was decreased and serotonin colonic tissue levels were increased three days after irradiation. Radiation-induced diarrhea was reduced by treatment with an antagonist of 5-HT3 receptors, granisetron, as were alterations of colonic motility and serotonin tissue levels. However, this treatment did not significantly ameliorate fluid

  18. Modelling of the spent fuel dissolution rate evolution for repository conditions. Matrix Alteration Model results and sensitivity analysis

    International Nuclear Information System (INIS)

    This paper focuses on how to extrapolate current knowledge of spent fuel matrix alteration processes from laboratory to repository conditions, i.e., the influence of changes in both the environmental conditions and the range of time scale considered. Therefore, a spent fuel matrix alteration model allowing the alteration rate evolution to be predicted as a function of both the host rock considered and evaluation time scale of interest is described. At present, the model assumes that alteration of the spent fuel will start when the groundwater reaches the solid surface and that only the radiolytic species of the groundwater (oxidants generated by α-radiation of spent fuel) will produce the surface oxidation process and subsequent matrix dissolution; O2, H2O2 and OH- are the species that react with UO2(s) for oxidation of the pellet surface. The dissolution process of the surface sites that are oxidized is modelled in two steps: first, a surface co-ordination of the oxidized layer with aqueous ligands and, second, detachment (dissolution) of the product species. Taking this mechanism into account, the model gives the evolution of the spent fuel matrix alteration rate over periods as long as 1,000,000 years. In this work the matrix alteration rate results obtained for two repository environments, granitic and argillaceous, will be presented. Furthermore, a sensitivity analysis study has been performed on the influence of the following variables: type of spent fuel considered, α-dose rate evolution, α-range in groundwater, carbonate and iron concentration in groundwater, H2 partial pressure, container time failure and specific surface area of the pellet. (author)

  19. DNA-nuclear matrix interactions and ionizing radiation sensitivity

    International Nuclear Information System (INIS)

    The association between inherent ionizing radiation sensitivity and DNA supercoil unwinding in mammalian cells suggests that the DNA-nuclear matrix attachment region (MAR) plays an important role in radiation response. In radioresistant cells, the MAR structure may exist in a more stable, open configuration, limiting DNA unwinding following strand break induction and maintaining DNA ends in close proximity for more rapid and accurate rejoining. In addition, the open configuration at these matrix attachment sites may serve to facilitate rapid DNA processing of breaks by providing (1) sites for repair proteins to collect and (2) energy to drive enzymatic reactions

  20. Alteration of dopamine receptor sensitivity by opiates and the subsequent effect of this alteration on opiate tolerance and dependence

    Energy Technology Data Exchange (ETDEWEB)

    Martin, J.R.

    1985-01-01

    The present study was undertaken to determine whether there is an alteration of dopamine receptor sensitivity following opiate administration, and whether this alteration has any influence on the development of opiate tolerance and dependence. Behavioral hypersensitivity to direct-acting dopamine agonists was observed in mice following acute or chronic morphine administration. Acute levorphanol administration also resulted in potentiation of dopamine agonist-induced behaviors. An increase in density of dopamine receptors, as measured by (/sup 3/H)butyrophenone binding accompanied the development of behavioral hypersensitivity. This increase was localized to the striatum, an area important in the mediation of dopamine-agonist induced behaviors. Naloxone or LiCl coadministered with the opiates prevented the development of hypersensitivity and the increase in density of dopamine receptors. Coadministration of lithium enhanced the development of acute and chronic tolerance. Lithium enhanced the development of dependence as determined by naloxone-induced hypothermia in chronically morphine-treated mice. Apomorphine enhanced naloxone-induced withdrawal in acutely dependent mice. This enhancement was blocked by coadministration of lithium with the opiates. These results suggest that dopamine receptor supersensitivity influences the degree of tolerance and dependence.

  1. Alteration of dopamine receptor sensitivity by opiates and the subsequent effect of this alteration on opiate tolerance and dependence

    International Nuclear Information System (INIS)

    The present study was undertaken to determine whether there is an alteration of dopamine receptor sensitivity following opiate administration, and whether this alteration has any influence on the development of opiate tolerance and dependence. Behavioral hypersensitivity to direct-acting dopamine agonists was observed in mice following acute or chronic morphine administration. Acute levorphanol administration also resulted in potentiation of dopamine agonist-induced behaviors. An increase in density of dopamine receptors, as measured by [3H]butyrophenone binding accompanied the development of behavioral hypersensitivity. This increase was localized to the striatum, an area important in the mediation of dopamine-agonist induced behaviors. Naloxone or LiCl coadministered with the opiates prevented the development of hypersensitivity and the increase in density of dopamine receptors. Coadministration of lithium enhanced the development of acute and chronic tolerance. Lithium enhanced the development of dependence as determined by naloxone-induced hypothermia in chronically morphine-treated mice. Apomorphine enhanced naloxone-induced withdrawal in acutely dependent mice. This enhancement was blocked by coadministration of lithium with the opiates. These results suggest that dopamine receptor supersensitivity influences the degree of tolerance and dependence

  2. Altered radiation recovery by DNA double-strand break inducers

    International Nuclear Information System (INIS)

    Identical biphasic time-dependent profiles of cell survival were obtained in V79 fibroblasts exposed to a split-dose protocol consisting of a fixed dose of γ-rays followed, at a variable time interval, either by a second exposure to radiation, or by contact with an equi-toxic amount of antitumor drugs acting to produce DNA double-strand breaks. The drugs used in this context were the neocarcinostatin antibiotic (NCS), which preferentially cleaves DNA in the linker region of nucleosomes, and etoposide (VP), whose major target is topoisomerase IIα, a nuclear matrix fraction-linked enzyme acting to relieve topological constraints in replicating DNA and mitotic chromosomes. Radiation-induced DNA strand break rejoining was not inhibited by either drug. The initial number of DNA strand breaks was consistently found o depend only on the radiation dose and/or on the drug concentration. However, the cytotoxicity they induced in combined treatment was determined in essence by the time elapsed after the first radiation exposure. While resistance to NCS and VP in non-irradiated, synchronized cells peaks in G2 phase of the cell cycle, enhanced drug susceptibility was observed within the radiation-induced G2 block. Concomitant exposure to drug and radiation also resulted in supra-additive cytotoxic interaction. Our data suggest that impaired split-dose radiation recovery dose not proceed from inhibition of DNA damage repair, but rather from additional double-strand breaks produced by drug or radiation during the time cells are in the dynamic process of DNA repair; a time range characterized by a dynamic DNA fragility. (authors)

  3. Effect of ionizing radiation on voltage-sensitive sodium channels in the brain

    International Nuclear Information System (INIS)

    It has generally been assumed that the mature central nervous system is not sensitive to ionizing radiation because cell division of neurons no longer occurs. In general, rather large doses have been required in order to observe changes in morphological, physiological, biochemical, and behavioral endpoints. In order to focus on one of the most fundamental mechanisms in the generation and propagation of action potentials, experiments were undertaken to determine whether ionizing radiation could alter the ability of the neurotoxins, veratridine and batrachotoxin, to stimulate /sup 22/Na uptake into synaptosomes. Synaptosomal preparations were irradiated with varying doses of high-energy electrons or gamma photons. Both qualities of radiation reduced /sup 22/Na uptake stimulated by either toxin after doses as low as 100 rad in a concentration-dependent manner. When concentration-response curves for the neurotoxins were derived at increasing doses of radiation, the maximum effectiveness of the toxins was progressively diminished. The data suggest that the central nervous system may be more sensitive to the effects of ionizing radiation than previously believed and that the effects observed may reflect a loss of viable sodium channels. Such effects may have biological significance

  4. Radiation-induced apoptosis in thymocytes: pH sensitization

    International Nuclear Information System (INIS)

    Thymocytes were used as a model system to study the effect of microenvironmental pH changes on the radiation-induced apoptosis. We found that the sensitivity of thymocytes toward radiation induced apoptosis is increased by increasing the pH of the incubation medium. The major sensitivity change occurs between pH 7 and 8. In a given cell suspension the results obtained were similar when the apoptosis evaluation was carried out either by counting the picnotic nuclei, or monitoring the fraction of apoptic nuclei by flow cytometry; both methods show a radiosensitization when the pH value of incubation media rises from 7 to 8. These results may be important when 'in vitro' experiments are performed with lymphoid cells, since changes in pH of the media may determine important changes in the results. (orig.)

  5. Mechanisms of alteration of the immune system by ionizing radiations: a basis for radiation protection

    Energy Technology Data Exchange (ETDEWEB)

    Bourguignon, M. [Direction Generale de la Surete Nucleaire et de la Radioprotection, 75 - Paris (France); Perez, M.; Dubner, D.; Michelin, S. [Autoridad Regulatoria Nuclear, Buenos Aires (Argentina); Carosella, E. [CEA, Service de Recherches en Hemato -Immunologie, 75 - Paris (France)

    2006-07-01

    Full text of publication follows: Alterations of the immune system appear in relationship with exposure to ionizing radiation (IR) in different situations, e.g., accidents, radiation therapy of cancer, prenatal irradiation, some human diseases with hypersensitivity to IR and aging. Thus, the comprehension of the mechanisms of the alterations of the immune system by IR is necessary to elaborate strategies of protection and to pave the way for future possible therapies. At least 9 mechanisms of alterations can be identified: 1- Apoptosis. Apoptosis is a key mechanism of the natural regulation of the immune system and plays also a key role in the response to IR: lymphocytes die rapidly by apoptosis after exposure. Different pathways of induction of apoptosis have been identified, and include p53 dependent and mitochondria mediated pathways, as well as CD95 and ROS initiation; 2- TCR mutations. The T cell antigen receptor is responsible to discriminate between self and non self. Mutations of the TCR may result from exposure to IR; 3- Modification of the Th1-Th2 balance. T helper cells may express 2 distinct secretion patterns: Th1 cytokines promote cell-mediated immunity while Th2 cytokines favor humoral immunity. Although the effects of IR on the Th1/Th2 balance remains controversial, an imbalance towards a Th2 profile is likely and patients with cancer and systemic auto-immune disease often present a switch from Th1 to Th2; 4- Bystander effects and genetic instability. Stimulatory effect or genomic instability have been observed in haematopoietic cells exposed to IR and related to a bystander mechanism. 5- Shift toward an inflammatory profile. Ionizing radiation may induce a persistent inflammatory profile as a result of dis-regulation of cytokine production; such a status of persistent inflammation has been observed in Hiroshima and Nagasaki survivors. 6- Modification of antigen presentation. Antigen presentation by dendritic cells is an essential function preceding

  6. Mechanisms of alteration of the immune system by ionizing radiations: a basis for radiation protection

    International Nuclear Information System (INIS)

    Full text of publication follows: Alterations of the immune system appear in relationship with exposure to ionizing radiation (IR) in different situations, e.g., accidents, radiation therapy of cancer, prenatal irradiation, some human diseases with hypersensitivity to IR and aging. Thus, the comprehension of the mechanisms of the alterations of the immune system by IR is necessary to elaborate strategies of protection and to pave the way for future possible therapies. At least 9 mechanisms of alterations can be identified: 1- Apoptosis. Apoptosis is a key mechanism of the natural regulation of the immune system and plays also a key role in the response to IR: lymphocytes die rapidly by apoptosis after exposure. Different pathways of induction of apoptosis have been identified, and include p53 dependent and mitochondria mediated pathways, as well as CD95 and ROS initiation; 2- TCR mutations. The T cell antigen receptor is responsible to discriminate between self and non self. Mutations of the TCR may result from exposure to IR; 3- Modification of the Th1-Th2 balance. T helper cells may express 2 distinct secretion patterns: Th1 cytokines promote cell-mediated immunity while Th2 cytokines favor humoral immunity. Although the effects of IR on the Th1/Th2 balance remains controversial, an imbalance towards a Th2 profile is likely and patients with cancer and systemic auto-immune disease often present a switch from Th1 to Th2; 4- Bystander effects and genetic instability. Stimulatory effect or genomic instability have been observed in haematopoietic cells exposed to IR and related to a bystander mechanism. 5- Shift toward an inflammatory profile. Ionizing radiation may induce a persistent inflammatory profile as a result of dis-regulation of cytokine production; such a status of persistent inflammation has been observed in Hiroshima and Nagasaki survivors. 6- Modification of antigen presentation. Antigen presentation by dendritic cells is an essential function preceding

  7. Hypoxic cell sensitizers and heavy charged-particle radiations

    International Nuclear Information System (INIS)

    Stationary-phase populations of Chinese hamster V-79 cells were irradiated with 250 kV X-rays and the Bragg peaks (spread to a width of 4 cm) of energetic He-, C-, Ne-, and A-ion beams produced at the 184-inch cyclotron and BEVALAC ar Lawrence Berkeley Laboratory. Survival curves were generated with each radiation for cells suspended in air-saturated and nitrogen-saturated medium with and without sensitizer present. The oxygen enhancement ratios (OERs) measured for X-rays with 1 mM metronidazole and 0.5 nM misonidazole were 2.0 and 1.6 respectively. The OERs without sensitizer for He-,C-, Ne-, and A-ion Bragg peaks were 2.4, 1.7, 1.6 and 1.4 respectively. For each type of radiation tested the presence of hypoxic-cell sensitizers resulted in an additional reduction in the measured OERs, indicating that these drugs should be of benefit in the radiotherapy planned with these and other high LET radiations. (author)

  8. The effects of polaprezinc on radiation-induced taste alterations

    International Nuclear Information System (INIS)

    The effects of polaprezinc (an insoluble zinc complex of L-carnosine) on taste abnormalities were investigated in 22 patients receiving radiation therapy to head and neck malignancies. The total doses to the tongue were 25.5-46.0 Gy (mean, 37.9 Gy). All patients received 75 mg of polaprezinc two times a day with an interval of 0-1,561 days (mean, 305.3 days) after the completion of radiation therapy. The duration of the drug administration was 25-353 days (mean, 96.9 days). Twenty patients (90.9%) were aware of an improvement of a partial or complete loss of taste. Polaprezinc is effective in improving loss of taste after radiation therapy. (author)

  9. The effects of polaprezinc on radiation-induced taste alterations

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Katsumasa; Togao, Osamu [Kyushu Univ., Fukuoka (Japan). Graduate School of Medical Sciences; Shikama, Naoto (and others)

    2001-06-01

    The effects of polaprezinc (an insoluble zinc complex of L-carnosine) on taste abnormalities were investigated in 22 patients receiving radiation therapy to head and neck malignancies. The total doses to the tongue were 25.5-46.0 Gy (mean, 37.9 Gy). All patients received 75 mg of polaprezinc two times a day with an interval of 0-1,561 days (mean, 305.3 days) after the completion of radiation therapy. The duration of the drug administration was 25-353 days (mean, 96.9 days). Twenty patients (90.9%) were aware of an improvement of a partial or complete loss of taste. Polaprezinc is effective in improving loss of taste after radiation therapy. (author)

  10. Effect of radiation on reconstitution of skin equivalent (dermal alterations)

    International Nuclear Information System (INIS)

    Dermal equivalents have been treated by single doses of gamma irradiation of 10, 20, 30 and 50 Gray. Numerations at different times show a dose and time dependant diminution of cellular population. This diminution is histologically observed in dermal part of reconstituted skin, in association with cellular and functional alterations of fibroblast cells. Modifications of epidermal epithelia are also noted in some reconstituted skin. This model would be useful to apprehend the effect of a dermal irradiation lesion on the later epidermization. (author)

  11. Alterations of nutritional status: impact of chemotherapy and radiation therapy

    International Nuclear Information System (INIS)

    The nutritional status of a cancer patient may be affected by the tumor, the chemotherapy and/or radiation therapy directed against the tumor, and by complications associated with that therapy. Chemotherpay-radiotherapy is not confined exclusively to malignant cell populations; thus, normal tissues may also be affected by the therapy and may contribute to specific nutritional problems. Impaired nutrition due to anorexia, mucositis, nausea, vomiting, and diarrhea may be dependent upon the specific chemotherapeutic agent, dose, or schedule utilized. Similar side effects from radiation therapy depend upon the dose, fractionation, and volume irradiated. When combined modality treatment is given the nutritional consequences may be magnified. Prospective, randomized clinical trials are underway to investigate the efficacy of nutritional support during chemotherapy-radiotherapy on tolerance to treatment, complications from treatment, and response rates to treatment. Preliminary results demonstrate that the administration of total parenteral nutrition is successful in maintaining weight during radiation therapy and chemotherapy, but that weight loss occurs after discontinuation of nutritional support. Thus, longterm evaluation is mandatory to learn the impact of nutritional support on survival, diease-free survival, and complication rates, as well as on the possible prevention of morbidity associated with aggressive chemotherapy-radiation therapy

  12. Radiation Exposure Alters Expression of Metabolic Enzyme Genes in Mice

    Science.gov (United States)

    Wotring, V. E.; Mangala, L. S.; Zhang, Y.; Wu, H.

    2011-01-01

    Most administered pharmaceuticals are metabolized by the liver. The health of the liver, especially the rate of its metabolic enzymes, determines the concentration of circulating drugs as well as the duration of their efficacy. Most pharmaceuticals are metabolized by the liver, and clinically-used medication doses are given with normal liver function in mind. A drug overdose can result in the case of a liver that is damaged and removing pharmaceuticals from the circulation at a rate slower than normal. Alternatively, if liver function is elevated and removing drugs from the system more quickly than usual, it would be as if too little drug had been given for effective treatment. Because of the importance of the liver in drug metabolism, we want to understand the effects of spaceflight on the enzymes of the liver and exposure to cosmic radiation is one aspect of spaceflight that can be modeled in ground experiments. Additionally, it has been previous noted that pre-exposure to small radiation doses seems to confer protection against later and larger radiation doses. This protective power of pre-exposure has been called a priming effect or radioadaptation. This study is an effort to examine the drug metabolizing effects of radioadaptation mechanisms that may be triggered by early exposure to low radiation doses.

  13. Gamma response study of radiation sensitive MOSFETs for their use as gamma radiation sensor

    Science.gov (United States)

    Srivastava, Saurabh; Aggarwal, Bharti; Singh, Arvind; Kumar, A. Vinod; Topkar, Anita

    2016-05-01

    Continuous monitoring of gamma dose is important in various fields like radiation therapy, space-related research, nuclear energy programs and high energy physics experiment facilities. The present work is focused on utilization of radiation-sensitive Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs) to monitor gamma radiation doses. Static characterization of these detectors was performed to check their expected current-voltage relationship. Threshold voltage and transconductance per unit gate to source voltage (K factor) were calculated from the experimental data. The detector was exposed to gamma radiation in both, with and without gate bias voltage conditions, and change in threshold voltage was monitored at different gamma doses. The experimental data was fitted to obtain equation for dependence of threshold voltage on gamma dose. More than ten times increase in sensitivity was observed in biased condition (+3 V) compared to the unbiased case.

  14. How far is cancer cured by radiation sensitization?

    International Nuclear Information System (INIS)

    Some types of cancer are not cured by radiation alone in view of histology, location, and size. In facing so-called radioresistant cancer, antineoplastic agents, hypoxic cell sensitizers, biological response modifiers, or hyperthermia are used in combination with radiation, with the aim of cancer cure. First of all, this chapter discusses the subject of 'what is tumor cure by radiation therapy'. Current conditions of the aforementioned combined modalities and the future perspectives are presented. The following subjects are covered: (1) tumor control - significance of the number of stem cells; (2) biological evaluation of chemo-radiotherapy with cisplatin; (3) clinical results and experience with combination of radiotherapy and radiosensitizers; (4) radiosensitization with hypoxic cell radiosensitizers - present status (5) hypoxic cell radiosensitizers - present status and problems from the viewpoint of clinical radiotherapy; (6) thermal radiosensitization in vitro and its implications for radiotherapy; (7) clinical assessment of thermoradiotherapy for breast cancer and cancer of the urinary bladder; (8) interactions of radiation and biological response modifiers in the treatment of malignant tumor; (9) improvement in the effects of radiation therapy with biological response modifiers. (N.K.)

  15. Sensitivity alteration of fiber Bragg grating sensors with additive micro-scale bi-material coatings

    Science.gov (United States)

    Zhang, Xixi; Alemohammad, Hamidreza; Toyserkani, Ehsan

    2013-02-01

    This paper describes a combined fabrication method for creating a bi-material micro-scale coating on fiber Bragg grating (FBG) optical sensors using laser-assisted maskless microdeposition (LAMM) and electroless nickel plating. This bi-material coating alters the sensitivity of the sensor where it also acts as a protective layer. LAMM is used to coat bare FBGs with a 1-2 µm thick conductive silver layer followed by the electroless nickel plating process to increase layer thickness to a desired level ranging from 1 to 80 µm. To identify an optimum coating thickness and predict its effect on the sensor's sensitivity to force and temperature, an optomechanical model is developed in this study. According to the model if the thickness of the Ni layer is 30-50 µm, maximum temperature sensitivity is achieved. Our analytical and experimental results suggest that the temperature sensitivity of the coated FBG with 1 µm Ag and 33 µm Ni is almost doubled compared to a bare FBG with sensitivity of 0.011 ± 0.001 nm °C-1. In contrast, the force sensitivity is decreased; however, this sensitivity reduction is less than the values reported in the literature.

  16. Sensitivity alteration of fiber Bragg grating sensors with additive micro-scale bi-material coatings

    International Nuclear Information System (INIS)

    This paper describes a combined fabrication method for creating a bi-material micro-scale coating on fiber Bragg grating (FBG) optical sensors using laser-assisted maskless microdeposition (LAMM) and electroless nickel plating. This bi-material coating alters the sensitivity of the sensor where it also acts as a protective layer. LAMM is used to coat bare FBGs with a 1–2 µm thick conductive silver layer followed by the electroless nickel plating process to increase layer thickness to a desired level ranging from 1 to 80 µm. To identify an optimum coating thickness and predict its effect on the sensor's sensitivity to force and temperature, an optomechanical model is developed in this study. According to the model if the thickness of the Ni layer is 30–50 µm, maximum temperature sensitivity is achieved. Our analytical and experimental results suggest that the temperature sensitivity of the coated FBG with 1 µm Ag and 33 µm Ni is almost doubled compared to a bare FBG with sensitivity of 0.011 ± 0.001 nm °C−1. In contrast, the force sensitivity is decreased; however, this sensitivity reduction is less than the values reported in the literature. (paper)

  17. Radiation-induced alterations of fracture healing biomechanics

    International Nuclear Information System (INIS)

    The effects of irradiation on the normal temporal progression of the physical properties of healing fractures were studied in a rat model. Fractures were surgically produced in the femur, stabilized with an intramedullary pin, and irradiated. One group of rats was exposed to 2,500 rads in divided doses over 2 weeks, beginning 3 days after fracture, and compared to a control group with fractures which were not irradiated. Animals were sacrificed at periodic intervals and the bones were tested to failure in torsion. The torque, stiffness, and energy increased and the angle decreased for the nonirradiated specimens in the expected fashion. This progression was deleteriously altered in the irradiated femurs

  18. Targeting Nucleophosmin 1 Represents a Rational Strategy for Radiation Sensitization

    International Nuclear Information System (INIS)

    Purpose: To test the hypothesis that small molecule targeting of nucleophosmin 1 (NPM1) represents a rational approach for radiosensitization. Methods and Materials: Wilde-type and NPM1-deficient mouse embryo fibroblasts (MEFs) were used to determine whether radiosensitization produced by the small molecule YTR107 was NPM1 dependent. The stress response to ionizing radiation was assessed by quantifying pNPM1, γH2AX, and Rad51 foci, neutral comet tail moment, and colony formation. NPM1 levels in a human-derived non-small-cell lung cancer (NSCLC) tissue microarray (TMA) were determined by immunohistochemistry. YTR107-mediated radiosensitization was assessed in NSCLC cell lines and xenografts. Results: Use of NPM1-null MEFs demonstrated that NPM1 is critical for DNA double- strand break (DSB) repair, that loss of NPM1 increases radiation sensitivity, and that YTR107-mediated radiosensitization is NPM1 dependent. YTR107 was shown to inhibit NPM1 oligomerization and impair formation of pNPM1 irradiation-induced foci that colocalized with γH2AX foci. Analysis of the TMA demonstrated that NPM1 is overexpressed in subsets of NSCLC. YTR107 inhibited DNA DSB repair and radiosensitized NSCLC lines and xenografts. Conclusions: These data demonstrate that YTR107-mediated targeting of NPM1 impairs DNA DSB repair, an event that increases radiation sensitivity

  19. Targeting Nucleophosmin 1 Represents a Rational Strategy for Radiation Sensitization

    Energy Technology Data Exchange (ETDEWEB)

    Sekhar, Konjeti R. [Department of Radiation Oncology, Vanderbilt University School of Medicine, Nashville, Tennessee (United States); Benamar, Mouadh [Department of Radiation Oncology, University of Virginia School of Medicine, Charlottesville, Virginia (United States); Venkateswaran, Amudhan; Sasi, Soumya [Department of Radiation Oncology, Vanderbilt University School of Medicine, Nashville, Tennessee (United States); Penthala, Narsimha R.; Crooks, Peter A. [Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, Arkansas (United States); Hann, Stephen R. [Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee (United States); Geng, Ling [Department of Radiation Oncology, Vanderbilt University School of Medicine, Nashville, Tennessee (United States); Balusu, Ramesh [Department of Internal Medicine, University of Kansas Medical Center, Kansas City, Kansas (United States); Abbas, Tarek [Department of Radiation Oncology, University of Virginia School of Medicine, Charlottesville, Virginia (United States); Freeman, Michael L., E-mail: michael.freeman@vanderbilt.edu [Department of Radiation Oncology, Vanderbilt University School of Medicine, Nashville, Tennessee (United States)

    2014-08-01

    Purpose: To test the hypothesis that small molecule targeting of nucleophosmin 1 (NPM1) represents a rational approach for radiosensitization. Methods and Materials: Wilde-type and NPM1-deficient mouse embryo fibroblasts (MEFs) were used to determine whether radiosensitization produced by the small molecule YTR107 was NPM1 dependent. The stress response to ionizing radiation was assessed by quantifying pNPM1, γH2AX, and Rad51 foci, neutral comet tail moment, and colony formation. NPM1 levels in a human-derived non-small-cell lung cancer (NSCLC) tissue microarray (TMA) were determined by immunohistochemistry. YTR107-mediated radiosensitization was assessed in NSCLC cell lines and xenografts. Results: Use of NPM1-null MEFs demonstrated that NPM1 is critical for DNA double- strand break (DSB) repair, that loss of NPM1 increases radiation sensitivity, and that YTR107-mediated radiosensitization is NPM1 dependent. YTR107 was shown to inhibit NPM1 oligomerization and impair formation of pNPM1 irradiation-induced foci that colocalized with γH2AX foci. Analysis of the TMA demonstrated that NPM1 is overexpressed in subsets of NSCLC. YTR107 inhibited DNA DSB repair and radiosensitized NSCLC lines and xenografts. Conclusions: These data demonstrate that YTR107-mediated targeting of NPM1 impairs DNA DSB repair, an event that increases radiation sensitivity.

  20. UV- and gamma-radiation sensitive mutants of Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Arabidopsis seedlings repair UV-induced DNA damage via light-dependent and -independent pathways. The mechanism of the ''dark repair'' pathway is still unknown. To determine the number of genes required for dark repair and to investigate the substrate-specificity of this process we isolated mutants with enhanced sensitivity to UV radiation in the absence of photoreactivating light. Seven independently derived UV sensitive mutants were isolated from an EMS-mutagenized population. These fell into six complementation groups, two of which (UVR1 and UVH1) have previously been defined. Four of these mutants are defective in the dark repair of UV-induced pyrimidine [6-4] pyrimidinone dimers. These four mutant lines are sensitive to the growth-inhibitory effects of gamma radiation, suggesting that this repair pathway is also involved in the repair of some type of gamma-induced DNA damage product. The requirement for the coordinate action of several different gene products for effective repair of pyrimidine dimers, as well as the nonspecific nature of the repair activity, is consistent with nucleotide excision repair mechanisms previously described in Saccharomyces cerevisiae and nonplant higher eukaryotes and inconsistent with substrate-specific base excision repair mechanisms found in some bacteria, bacteriophage, and fungi. (author)

  1. Genetic and epigenetic features in radiation sensitivity. Part II: implications for clinical practice and radiation protection

    Energy Technology Data Exchange (ETDEWEB)

    Bourguignon, Michel H. [Direction Generale de la Surete Nucleaire et de la Radioprotection, Paris Cedex 12 (France); CEA-DSV-DRM Hopital, Service de Recherches en Hemato-Immunologie, Saint Louis, Paris (France); Gisone, Pablo A.; Perez, Maria R.; Michelin, Severino; Dubner, Diana; Giorgio, Marina di [Autoridad Regulatoria Nuclear, Laboratorio de Radiopatologia, Buenos Aires (Argentina); Carosella, Edgardo D. [CEA-DSV-DRM Hopital, Service de Recherches en Hemato-Immunologie, Saint Louis, Paris (France)

    2005-03-01

    Recent progress especially in the field of gene identification and expression has attracted greater attention to the genetic and epigenetic susceptibility to cancer, possibly enhanced by ionising radiation. This issue is especially important for radiation therapists since hypersensitive patients may suffer from adverse effects in normal tissues following standard radiation therapy, while normally sensitive patients could receive higher doses of radiation, offering a better likelihood of cure for malignant tumours. Although only a small percentage of individuals are ''hypersensitive'' to radiation effects, all medical specialists using ionising radiation should be aware of the aforementioned progress in medical knowledge. The present paper, the second of two parts, reviews human disorders known or strongly suspected to be associated with hypersensitivity to ionising radiation. The main tests capable of detecting such pathologies in advance are analysed, and ethical issues regarding genetic testing are considered. The implications for radiation protection of possible hypersensitivity to radiation in a part of the population are discussed, and some guidelines for nuclear medicine professionals are proposed. (orig.)

  2. Genetic and epigenetic features in radiation sensitivity. Part II: implications for clinical practice and radiation protection.

    Science.gov (United States)

    Bourguignon, Michel H; Gisone, Pablo A; Perez, Maria R; Michelin, Severino; Dubner, Diana; Giorgio, Marina Di; Carosella, Edgardo D

    2005-03-01

    Recent progress especially in the field of gene identification and expression has attracted greater attention to the genetic and epigenetic susceptibility to cancer, possibly enhanced by ionising radiation. This issue is especially important for radiation therapists since hypersensitive patients may suffer from adverse effects in normal tissues following standard radiation therapy, while normally sensitive patients could receive higher doses of radiation, offering a better likelihood of cure for malignant tumours. Although only a small percentage of individuals are "hypersensitive" to radiation effects, all medical specialists using ionising radiation should be aware of the aforementioned progress in medical knowledge. The present paper, the second of two parts, reviews human disorders known or strongly suspected to be associated with hypersensitivity to ionising radiation. The main tests capable of detecting such pathologies in advance are analysed, and ethical issues regarding genetic testing are considered. The implications for radiation protection of possible hypersensitivity to radiation in a part of the population are discussed, and some guidelines for nuclear medicine professionals are proposed. PMID:15692806

  3. Genetic and epigenetic features in radiation sensitivity. Part II: implications for clinical practice and radiation protection

    International Nuclear Information System (INIS)

    Recent progress especially in the field of gene identification and expression has attracted greater attention to the genetic and epigenetic susceptibility to cancer, possibly enhanced by ionising radiation. This issue is especially important for radiation therapists since hypersensitive patients may suffer from adverse effects in normal tissues following standard radiation therapy, while normally sensitive patients could receive higher doses of radiation, offering a better likelihood of cure for malignant tumours. Although only a small percentage of individuals are ''hypersensitive'' to radiation effects, all medical specialists using ionising radiation should be aware of the aforementioned progress in medical knowledge. The present paper, the second of two parts, reviews human disorders known or strongly suspected to be associated with hypersensitivity to ionising radiation. The main tests capable of detecting such pathologies in advance are analysed, and ethical issues regarding genetic testing are considered. The implications for radiation protection of possible hypersensitivity to radiation in a part of the population are discussed, and some guidelines for nuclear medicine professionals are proposed. (orig.)

  4. Analysis of radiation-induced genome alterations in Vigna unguiculata

    Directory of Open Access Journals (Sweden)

    van der Vyver C

    2011-09-01

    Full Text Available Christell van der Vyver1, B Juan Vorster2, Karl J Kunert3, Christopher A Cullis41Institute for Plant Biotechnology, Department of Genetics, University of Stellenbosch, Stellenbosch, South Africa; 2Department of Plant Production and Soil Science, and 3Department of Plant Science, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa; 4Case Western Reserve University, Department of Biology, Cleveland, OH, USAAbstract: Seeds from an inbred Vigna unguiculata (cowpea cultivar were gamma-irradiated with a dose of 180 Gy in order to identify and characterize possible mutations. Three techniques, ie, random amplified polymorphic DNA, microsatellites, and representational difference analysis, were used to characterize possible DNA variation among the mutants and nonirradiated control plants both immediately after irradiation and in subsequent generations. A large portion of putative radiation-induced genome changes had significant similarities to chloroplast sequences. The frequency of mutation at three of these isolated polymorphic regions with chloroplast similarity was further determined by polymerase chain reaction screening using a large number of individual parental, M1, and M2 plants. Analysis of these sequences indicated that the rate at which various regions of the genome is mutated in irradiation experiments differs significantly and also that mutations have variable “repair” rates. Furthermore, regions of the nuclear DNA derived from the chloroplast genome are highly susceptible to modification by radiation treatment. Overall, data have provided detailed information on the effects of gamma irradiation on the cowpea genome and about the ability of the plant to repair these genome changes in subsequent plant generations.Keywords: mutation breeding, gamma radiation, genetic mutations, cowpea, representational difference analysis

  5. Construction and isolation of radiation sensitive mutants of Escherichia Coli

    International Nuclear Information System (INIS)

    Damage to DNA by ionizing radiation consists mainly of single (SSB) and double (DSB) strand breaks as well as several types of base alterations, all of which may be removed by different repair mechanisms. Radiation also induces the SOS response, a set of repair and/or damage tolerance genes involved in functions such as replication arrest, excision and recombination repair, increase of both spontaneous and induced mutation and prophage induction, among others. The degree of SOS induction is related to the type and amount of damage and may be easily determined by a simple colorimetric assay, the SOS chromo test. In order to investigate the role of protection and/or repair genes on bacterial radiosensitivity, E. coli strains defective in either oxyR, recJ or recO genes were constructed and their respective SOS response to radiation, duly examined. The results show that although lack of regulatory gene oxyR increases radiosensitivity, it is the deficiencies in recJ and recO which seem to be more important. Both genes appear to take part in the repair of DSB and according to SOS measurements, their role is related also to damage processing conducent to the SOS triggering signal. A hypothetical working mechanism for the purpose, partially supported by the data is proposed. (Author)

  6. Altered sensitization patterns to sweet food stimuli in patients recovered from anorexia and bulimia nervosa.

    Science.gov (United States)

    Wagner, Angela; Simmons, Alan N; Oberndorfer, Tyson A; Frank, Guido K W; McCurdy-McKinnon, Danyale; Fudge, Julie L; Yang, Tony T; Paulus, Martin P; Kaye, Walter H

    2015-12-30

    Recent studies show that higher-order appetitive neural circuitry may contribute to restricted eating in anorexia nervosa (AN) and overeating in bulimia nervosa (BN). The purpose of this study was to determine whether sensitization effects might underlie pathologic eating behavior when a taste stimulus is administered repeatedly. Recovered AN (RAN, n=14) and BN (RBN, n=15) subjects were studied in order to avoid the confounding effects of altered nutritional state. Functional magnetic resonance imaging (fMRI) measured higher-order brain response to repeated tastes of sucrose (caloric) and sucralose (non-caloric). To test sensitization, the neuronal response to the first and second administration was compared. RAN patients demonstrated a decreased sensitization to sucrose in contrast to RBN patients who displayed the opposite pattern, increased sensitization to sucrose. However, the latter was not as pronounced as in healthy control women (n=13). While both eating disorder subgroups showed increased sensitization to sucralose, the healthy controls revealed decreased sensitization. These findings could reflect on a neuronal level the high caloric intake of RBN during binges and the low energy intake for RAN. RAN seem to distinguish between high energy and low energy sweet stimuli while RBN do not. PMID:26596520

  7. Altered thermal sensitivity in facial skin in chronic whiplash-associated disorders

    Institute of Scientific and Technical Information of China (English)

    Birgitta Haggman-Henrikson; Ewa Lampa; Erik Nordh

    2013-01-01

    There is a close functional relationship between the jaw and neck regions and it has been suggested that trigeminal sensory impairment can follow whiplash injury. Inclusion of manageable routines for valid assessment of the facial sensory capacity is thus needed for comprehensive evaluations of patients exposed to such trauma. The present study investigated facial thermal thresholds in patients with chronic whiplash-associated disorders (WADs) with both a qualitative method and quantitative sensory testing (QST). Ten women with pain and dysfunction following a whiplash injury were compared to 10 healthy age-matched women. Thermal detection thresholds were assessed by qualitative chair-side testing and by QST according to the method-of-limits. Seven test sites in the facial skin (overlying each trigeminal branch bilaterally, and the midpoint of the chin) were examined. The detection warm and cold thresholds were defined as the mean values of 10 individual thresholds. For the WAD patients, the qualitative assessment demonstrated both reduced and increased sensitivity compared to the healthy, whereas QST systematically showed significantly higher detection thresholds (i.e., decreased sensitivity) for both cold and warm stimuli. For the individuals who were assessed as having increased sensitivity in the qualitative assessment, the QST displayed either normal or higher thresholds, i.e., decreased sensitivity. The results suggest that QST is more sensitive for detecting thermal sensory disturbances in the face than a qualitative method. The impaired thermal sensitivity among the patients corroborates the notion of altered thermal detection capacity induced by WAD-related pain.

  8. Position sensitive detection of neutrons in high radiation background field

    International Nuclear Information System (INIS)

    We present the development of a high-resolution position sensitive device for detection of slow neutrons in the environment of extremely high γ and e− radiation background. We make use of a planar silicon pixelated (pixel size: 55 × 55 μm2) spectroscopic Timepix detector adapted for neutron detection utilizing very thin 10B converter placed onto detector surface. We demonstrate that electromagnetic radiation background can be discriminated from the neutron signal utilizing the fact that each particle type produces characteristic ionization tracks in the pixelated detector. Particular tracks can be distinguished by their 2D shape (in the detector plane) and spectroscopic response using single event analysis. A Cd sheet served as thermal neutron stopper as well as intensive source of gamma rays and energetic electrons. Highly efficient discrimination was successful even at very low neutron to electromagnetic background ratio about 10−4

  9. SENSITIVITY OF THE CUMIN SEEDS ASSOCIATED FUNGI TO GAMMA RADIATION

    International Nuclear Information System (INIS)

    The present study was carried out to investigate the sensitivity of fungi associated to cumin seeds for gamma radiation. In this regard, the isolated seed associated fungi from the cumin seeds were fifteen fungal species belonging to five genera. The fungal species concerning, Aspergillus ochraceus, Fusarium oxysporium and Aspergillus flavus were the predominant fungi in percentages of 17.8, 15.83 and 12.78 %, respectively. Aspergillus ochraceus was the most effective prevalent fungi on the seed germination causing highest percentage of seed invasion followed by Fusarium oxysporium and Aspergillus flavus. The amylolytic, proteolytic and lipolytic activity and mycotoxin production of the three predominant fungi were negatively influenced by gamma radiation when exposed to doses of 1.0 , 1.5 , 2.5 , 3.5 , 5.0 and 7.5 kGy a behaviour which was parallel to the inhibition in the amount of growth by gamma irradiation

  10. Protracted radiation-induced alterations in hematopoietic repair and recovery

    International Nuclear Information System (INIS)

    Pathologic predisposition of beagle dogs under chronic, low daily dose (7.5 cGy day-1) whole-body gamma irradiation has been studied relative to molecular repair and hematopoietic competency. Molecular repair, assessed by a microscopy-based unscheduled DNA synthesis (UDS) response, was measured within proliferative and nonproliferative marrow myeloid elements of dogs with markedly different hematopoietic capacities (low capacity, aplasia-prone [AA+] versus high capacity, myeloproliferative disease-prone [MPD+]) under protracted radiation stress. Results indicated that protracted exposure elicited a net increase in UDS-repair capacity that was largely independent of exposure duration. This enhanced capacity resulted from the increased strength of the UDS signal together with an expanded number of positively responding cells. The combined response was strong in primitive blasts and weak in more differentiated myelocytic cells. The UDS repair response of the MPD+ dogs was significantly greater than that of the AA+ animals and was clearly modified relative to the controls. These results suggest that both resiliency and pathologic potential of the hematopoietic system under protracted radiation stress is, in part, associated with an augmentable DNA repair within the more primitive myeloid marrow elements. (author)

  11. Sensitization of radiation-induced cell death by genistein

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Rim; Kim, In Gyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-03-15

    A number of epidemiological studies as well as biological experiments, showed that genistein, one of the isoflavone, prevents prostate cancer occurrence. In this study, we showed that genistein inhibited the cell proliferation of human promyeoltic leukemia HL-60 cells and induced G2/M phase arrest. In addition, combination of genistein treatment and {gamma}-irradiation displayed synergistic effect in apoptotic cell death of HL-60 cells. This means that the repair of genistein-induced DNA damage was hindered by {gamma}-irradiation and thus cell death was increased. In conclusion, genistein is one of the important chemicals that sensitize radiation-induced cell death.

  12. Position sensitive detection of neutrons in high radiation background field

    Czech Academy of Sciences Publication Activity Database

    Vavřík, Daniel; Jakůbek, Jan; Vacík, Jiří; Pospíšil, S.

    2014-01-01

    Roč. 85, č. 1 (2014), s. 013304. ISSN 0034-6748 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0060; GA ČR(CZ) GBP108/12/G108; GA TA ČR(CZ) TA01010237 Institutional support: RVO:68378297 ; RVO:61389005 Keywords : neutrons * pattern recognition * position sensitive detectors * radiation detectors * silicon detectors Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering; BG - Nuclear, Atomic and Molecular Physics, Colliders (UJF-V) Impact factor: 1.614, year: 2014 http://scitation.aip.org/content/aip/journal/rsi/85/1/10.1063/1.4862478

  13. Radiation and cadmium induced biochemical alterations in mouse kidney

    International Nuclear Information System (INIS)

    In the present investigation radiation and cadmium induced biochemical changes in the kidney of Swiss albino mice have been studied. Materials and Methods: For this purpose, adult male Swiss albino mice (6-8 weeks old) were divided into four groups. Group I (sham-irradiated), Group II (treated with CdCl2 solution 20 ppm), Group III (irradiated with 1.25, 2.5 and 5.0 Gy gamma rays), Group IV (both irradiated with 1.25, 2.5 and 5.0 Gy gamma rays and treated with CdCl2 solution). The animals were autopsied after 1, 2, 4, 7, 14 and 28 days of treatment. The kidney was taken out and different biochemical parameters, such as total proteins, glycogen, cholesterol, acid phosphatase activity, alkaline phosphatase activity, DNA and RNA were estimated. Results: In irradiated animals, the values of total proteins, glycogen, acid phosphatase, alkaline phosphatase activity and RNA increased continuously up to day-7 and decreased thereafter up to day-28. The changes were dose dependent. In CdCl2 treated animals, the values of glycogen and total proteins decreased during the early intervals and increased thereafter whereas the values of acid and alkaline phosphatase activity and RNA increased during early Intervals and decreased thereafter, The values of cholesterol and DNA showed decrease in all the experimental groups (except group I) up to day-7 and increase thereafter up to day-28. After combined treatment also, the parameters followed the same pattern of increase and decrease, but the changes were more pronounced indicating their synergistic effect. The biochemical parameters showed highly significant values (P<0.001) as compared to normal ones. Conclusion: These results indicate that combined treatment of cadmium and gamma radiations causes synergistic or additive effect

  14. Radiation-induced alterations of histone post-translational modification levels in lymphoblastoid cell lines

    International Nuclear Information System (INIS)

    Radiation-induced alterations in posttranslational histone modifications (PTMs) may affect the cellular response to radiation damage in the DNA. If not reverted appropriately, altered PTM patterns may cause long-term alterations in gene expression regulation and thus lead to cancer. It is therefore important to characterize radiation-induced alterations in PTM patterns and the factors affecting them. A lymphoblastoid cell line established from a normal donor was used to screen for alterations in methylation levels at H3K4, H3K9, H3K27, and H4K20, as well as acetylation at H3K9, H3K56, H4K5, and H4K16, by quantitative Western Blot analysis at 15 min, 1 h and 24 h after irradiation with 2 Gy and 10 Gy. The variability of alterations in acetylation marks was in addition investigated in a panel of lymphoblastoid cell lines with differing radiosensitivity established from lung cancer patients. The screening procedure demonstrated consistent hypomethylation at H3K4me3 and hypoacetylation at all acetylation marks tested. In the panel of lymphoblastoid cell lines, however, a high degree of inter-individual variability became apparent. Radiosensitive cell lines showed more pronounced and longer lasting H4K16 hypoacetylation than radioresistant lines, which correlates with higher levels of residual γ-H2AX foci after 24 h. So far, the factors affecting extent and duration of radiation-induced histone alterations are poorly defined. The present work hints at a high degree of inter-individual variability and a potential correlation of DNA damage repair capacity and alterations in PTM levels

  15. Proximity to Delivery Alters Insulin Sensitivity and Glucose Metabolism in Pregnant Mice.

    Science.gov (United States)

    Musial, Barbara; Fernandez-Twinn, Denise S; Vaughan, Owen R; Ozanne, Susan E; Voshol, Peter; Sferruzzi-Perri, Amanda N; Fowden, Abigail L

    2016-04-01

    In late pregnancy, maternal insulin resistance occurs to support fetal growth, but little is known about insulin-glucose dynamics close to delivery. This study measured insulin sensitivity in mice in late pregnancy at day 16 (D16) and near term at D19. Nonpregnant (NP) and pregnant mice were assessed for metabolite and hormone concentrations, body composition by DEXA, tissue insulin signaling protein abundance by Western blotting, glucose tolerance and utilization, and insulin sensitivity using acute insulin administration and hyperinsulinemic-euglycemic clamps with [(3)H]glucose infusion. Whole-body insulin resistance occurred in D16 pregnant dams in association with basal hyperinsulinemia, insulin-resistant endogenous glucose production, and downregulation of several proteins in hepatic and skeletal muscle insulin signaling pathways relative to NP and D19 values. Insulin resistance was less pronounced at D19, with restoration of NP insulin concentrations, improved hepatic insulin sensitivity, and increased abundance of hepatic insulin signaling proteins. At D16, insulin resistance at whole-body, tissue, and molecular levels will favor fetal glucose acquisition, while improved D19 hepatic insulin sensitivity will conserve glucose for maternal use in anticipation of lactation. Tissue sensitivity to insulin, therefore, alters differentially with proximity to delivery in pregnant mice, with implications for human and other species. PMID:26740602

  16. The sensitivity of human mesenchymal stem cells to ionizing radiation

    International Nuclear Information System (INIS)

    Purpose: Recent studies have shown that mesenchymal stem cells (MSCs) obtained from bone marrow transplantation patients originate from the host. This clinical observation suggests that MSCs in their niches could be resistant to irradiation. However, the biologic responses of bone marrow MSCs to irradiation have rarely been described in the literature. Methods and Materials: In this study, human bone marrow-derived, clonally expanded MSCs were used to investigate their sensitivity to irradiation in vitro, and the cellular mechanisms that may facilitate resistance to irradiation. The human lung cancer cell line A549 and the breast cancer cell line HCC1937 were used as controls for radiosensitivity; the former line has been shown to be radioresistant and the latter radiosensitive. We then examined their in vitro biologic changes and sensitivities to radiation therapy. Results: Our results suggest that MSCs are characterized as resistant to irradiation. Several cellular mechanisms were demonstrated that may facilitate resistance to irradiation: ATM protein phosphorylation, activation of cell-cycle checkpoints, double-strand break repair by homologous recombination and nonhomologous end joining (NHEJ), and the antioxidant capacity for scavenging reactive oxygen species. Conclusions: As demonstrated, MSCs possess a better antioxidant reactive oxygen species-scavenging capacity and active double-strand break repair to facilitate their radioresistance. These findings provide a better understanding of radiation-induced biologic responses in MSCs and may lead to the development of better strategies for stem cell treatment and cancer therapy

  17. Radiation-induced alteration of gene expression in rat liver

    International Nuclear Information System (INIS)

    Exposure of rats to high dose of γ-radiation (200 Gy) significantly enhanced the ability of mitochondria to accumulate and retain exogenously added Ca2+ one hour after irradiation. 48 hours after irradiation no differences in Ca2+ transporting parameters between mitochondria from control and irradiated animals were found. The stability of mitochondrial membrane potential - the driving force for Ca2+ accumulation and retention, depends on the expression of bcl-2 gene, whose product not only participates in the regulation of Ca2+ fluxes in, but also demonstrates antioxidant properties. The overexpression of this gene was shown to protect cell mitochondria against oxidative stress. However, the investigation of bcl-2 expression in rat liver did not show any significant changes neither 1 nor 48 hours after irradiation. Taking into account that the damage of mitochondria induced action of oxygen radicals and Ca2+ can be prevented by antioxidants, the expression of genes encoded superoxiddismutase and catalase was studied. Expression was gradually stimulated. However, under conditions employed in experiments, direct changes. Presumably this can be explained by a post-translational regulation of the activity of these enzymes. (authors)

  18. Responses of cells to radiation sensitizers: methods of analysis

    International Nuclear Information System (INIS)

    Several well-known transforms of the widely-used Michaelis-Menten function linearize the kinetics of many competition reactions such as enzymatic processes. These transforms allow easy and accurate evaluation of the mathematical constants of the system, as well as giving clues to the various mechanisms involved in these competitions. Linearization techniques are applied to several sets of data from several authors that describe the radiation sensitivity determined by varied concentrations of two sensitizers - O2 and misonidazole. It is shown that, when the increment in sensitivity determined at the various concentrations of sensitizer is used as the dependent variable, straight lines are obtained from various sets of data when either the so-called Lineweaver-Burk or the Eadie-Hofstee transform is used. The E-H transform results in a better distribution of data points and, accordingly, is preferred. The transform allows recognition of two oxygen-dependent processes (one at low [O2] and one at high [O2]) in data apparently demonstrating but one; and, as well, two processes determined at two levels of misonidazole from data that appeared to describe one. These results support the evidence given earlier for two oxygen effects in other cells. Also, the transform reveals that in different cell systems two inhibitors of the oxygen effect appear to act in the same manner on one oxygen effect and in a different way on the other. The value of the transform in analysing mechanisms of sensitization is examined, and its further potential use in understanding the action of chemical protective agents pointed out. (author)

  19. Intervention of oxygen-control ability to radiation sensitivity, cell aging and cell transformation

    International Nuclear Information System (INIS)

    Oxygen is essential for life, and cells have therefore developed numerous adaptive responses to oxygen change. Here, we examined the difference in oxygen-control functions of human (HE), mouse (ME), and Syrian hamster embryo (SHE) cells cultured under different oxygen conditions (0.5%, 2% and 20%), and also examined whether oxygen tensions contributed to cellular lifespan and transformation. HE cells had their replicative lifespan slightly extended under hypoxic (0.5% and 2% oxygen) conditions, but were not immortalized under any of the oxygen concentrations. On the other hand, although ME cells cultured under 20% oxygen tension decreased their proliferation potency temporarily at early stage, all rodent cells were immortalized and acquired anchorage-independency, regardless of oxygen tension. These results suggest that cellular oxygen control function is related to sensitivities cellular immortalization and transformation. To understand intervention of oxygen control ability on cellular immortalization and transformation, we examined the intracellular oxidative level, mitochondria functions and radiation sensitivity. Intracellular oxidative levels of hypoxically cultured rodent cells were significantly enhanced. Mitochondrial membrane potential was altered depend on oxygen tensions, but the change was not parallel to mitochondria number in rodent cells. ME cells were particularly sensitive to oxygen change, and showed a clear oxygen effect on the X-ray survival. However, there was no difference in frequency of radiation-induced micronuclei between HE and ME cells. These results suggest that the response to oxygen change differs markedly in HE and rodent cells. (author)

  20. Advances in radiation biology: Relative radiation sensitivities of human organ systems. Volume 12

    Energy Technology Data Exchange (ETDEWEB)

    Lett, J.T.; Altman, K.I.; Ehmann, U.K.; Cox, A.B.

    1987-01-01

    This volume is a thematically focused issue of Advances in Radiation Biology. The topic surveyed is relative radiosensitivity of human organ systems. Topics considered include relative radiosensitivities of the thymus, spleen, and lymphohemopoietic systems; relative radiosensitivities of the small and large intestine; relative rediosensitivities of the oral cavity, larynx, pharynx, and esophagus; relative radiation sensitivity of the integumentary system; dose response of the epidermal; microvascular, and dermal populations; relative radiosensitivity of the human lung; relative radiosensitivity of fetal tissues; and tolerance of the central and peripheral nervous system to therapeutic irradiation.

  1. Advances in radiation biology: Relative radiation sensitivities of human organ systems. Volume 12

    International Nuclear Information System (INIS)

    This volume is a thematically focused issue of Advances in Radiation Biology. The topic surveyed is relative radiosensitivity of human organ systems. Topics considered include relative radiosensitivities of the thymus, spleen, and lymphohemopoietic systems; relative radiosensitivities of the small and large intestine; relative rediosensitivities of the oral cavity, larynx, pharynx, and esophagus; relative radiation sensitivity of the integumentary system; dose response of the epidermal; microvascular, and dermal populations; relative radiosensitivity of the human lung; relative radiosensitivity of fetal tissues; and tolerance of the central and peripheral nervous system to therapeutic irradiation

  2. Sensitivity and Acclimation of Three Canopy-Forming Seaweeds to UVB Radiation and Warming

    KAUST Repository

    Xiao, Xi

    2015-12-02

    Canopy-forming seaweeds, as primary producers and foundation species, provide key ecological services. Their responses to multiple stressors associated with climate change could therefore have important knock-on effects on the functioning of coastal ecosystems. We examined interactive effects of UVB radiation and warming on juveniles of three habitat-forming subtidal seaweeds from Western Australia–Ecklonia radiata, Scytothalia dorycarpa and Sargassum sp. Fronds were incubated for 14 days at 16–30°C with or without UVB radiation and growth, health status, photosynthetic performance, and light absorbance measured. Furthermore, we used empirical models from the metabolic theory of ecology to evaluate the sensitivity of these important seaweeds to ocean warming. Results indicated that responses to UVB and warming were species specific, with Sargassum showing highest tolerance to a broad range of temperatures. Scytothalia was most sensitive to elevated temperature based on the reduced maximum quantum yields of PSII; however, Ecklonia was most sensitive, according to the comparison of activation energy calculated from Arrhenius’ model. UVB radiation caused reduction in the growth, physiological responses and thallus health in all three species. Our findings indicate that Scytothalia was capable of acclimating in response to UVB and increasing its light absorption efficiency in the UV bands, probably by up-regulating synthesis of photoprotective compounds. The other two species did not acclimate over the two weeks of exposure to UVB. Overall, UVB and warming would severely inhibit the growth and photosynthesis of these canopy-forming seaweeds and decrease their coverage. Differences in the sensitivity and acclimation of major seaweed species to temperature and UVB may alter the balance between species in future seaweed communities under climate change.

  3. Sensitivity and Acclimation of Three Canopy-Forming Seaweeds to UVB Radiation and Warming.

    Directory of Open Access Journals (Sweden)

    Xi Xiao

    Full Text Available Canopy-forming seaweeds, as primary producers and foundation species, provide key ecological services. Their responses to multiple stressors associated with climate change could therefore have important knock-on effects on the functioning of coastal ecosystems. We examined interactive effects of UVB radiation and warming on juveniles of three habitat-forming subtidal seaweeds from Western Australia-Ecklonia radiata, Scytothalia dorycarpa and Sargassum sp. Fronds were incubated for 14 days at 16-30°C with or without UVB radiation and growth, health status, photosynthetic performance, and light absorbance measured. Furthermore, we used empirical models from the metabolic theory of ecology to evaluate the sensitivity of these important seaweeds to ocean warming. Results indicated that responses to UVB and warming were species specific, with Sargassum showing highest tolerance to a broad range of temperatures. Scytothalia was most sensitive to elevated temperature based on the reduced maximum quantum yields of PSII; however, Ecklonia was most sensitive, according to the comparison of activation energy calculated from Arrhenius' model. UVB radiation caused reduction in the growth, physiological responses and thallus health in all three species. Our findings indicate that Scytothalia was capable of acclimating in response to UVB and increasing its light absorption efficiency in the UV bands, probably by up-regulating synthesis of photoprotective compounds. The other two species did not acclimate over the two weeks of exposure to UVB. Overall, UVB and warming would severely inhibit the growth and photosynthesis of these canopy-forming seaweeds and decrease their coverage. Differences in the sensitivity and acclimation of major seaweed species to temperature and UVB may alter the balance between species in future seaweed communities under climate change.

  4. Micronuclei: sensitivity for the detection of radiation induced damage

    International Nuclear Information System (INIS)

    The in vitro cytokinesis-block (CB) micronucleus (MN) assay for human peripheral blood has been used extensively for the assessment of chromosomal damage induced by ionizing radiation and chemicals and considered a suitable biological dosimeter for estimating in vivo whole body exposures, particularly in the case of large scale radiation accidents. One of the major drawbacks of the MN assay is its reduced sensitivity for the detection of damage induced by low doses of low LET radiation, due to the high variability among the spontaneous MN frequencies. It is suggested that age, smoking habit and sex are the main confounding factors that contribute to the observed variability. Previous work in our laboratory, shows a significant positive correlation of the spontaneous and radiation induced MN frequencies with age and smoking habit, the latter being the strongest confounder. These findings led to in vitro studies of the dose-response relationships for smoking and non smoking donors evaluated separately, using 60Co γ rays. The objectives of the present work are: 1-To increase the amount of data of the dose-response relationships, using γ rays from a 60Co source, for smoking and non smoking donors, in order to find, if applicable, a correction factor for the calibration curve that takes into account the smoking habit of the individual in the case of accidental overexposure dose assessment, particularly in the low dose range. 2-To establish general conclusions on the current state of the technique. The sample for smoking and non smoking calibration curves was enlarged in the range of 0Gy to 2Gy. The fitting of both curves, performed up to the 2Gy dose, resulted in a linear quadratic model. MN distribution among bi nucleated cells was found to be over dispersed with respect to Poisson distribution, the average ratio of variance to mean being 1.13 for non smokers and 1.17 for smokers. Each fitted calibration curve, for smoking and non smoking donors, fell within the 95

  5. Law on alteration of the radiation protection law (1958:110)

    International Nuclear Information System (INIS)

    The alteration of the radiation protection law conserns the penalty for illegal import of radioactive materials. The following activities lead to penalty according to the law: performing radiologic work illegally, not conforming to prohibition given by legal authorities, or giving wrong declarations of radioactive materials to legal authorities. (K.K.)

  6. Altered zinc sensitivity of NMDA receptors harboring clinically-relevant mutations.

    Science.gov (United States)

    Serraz, Benjamin; Grand, Teddy; Paoletti, Pierre

    2016-10-01

    Recent human genetic studies have identified a surprisingly high number of alterations in genes encoding NMDA receptor (NMDAR) subunits in several common brain diseases. Among NMDAR subunits, the widely-expressed GluN2A subunit appears particularly affected, with tens of de novo or inherited mutations associated with neurodevelopmental conditions including childhood epilepsies and cognitive deficits. Despite the increasing identification of NMDAR mutations of clinical interest, there is still little information about the effects of the mutations on receptor and network function. Here we analyze the impact on receptor expression and function of nine GluN2A missense (i.e. single-point) mutations targeting the N-terminal domain, a large regulatory region involved in subunit assembly and allosteric signaling. While several mutations produced no or little apparent effect on receptor expression, gating and pharmacology, two showed a drastic expression phenotype and two resulted in marked alterations in the sensitivity to zinc, a potent allosteric inhibitor of GluN1/GluN2A receptors and modulator of excitatory synaptic transmission. Surprisingly, both increase (GluN2A-R370W) and decrease (GluN2A-P79R) of zinc sensitivity were observed on receptors containing either one or two copies of the mutated subunits. Overexpression of the mutant subunits in cultured rat neurons confirmed the results from heterologous expression. These results, together with previously published data, indicate that disease-causing mutations in NMDARs produce a wide spectrum of receptor alterations, at least in vitro. They also point to a critical role of the zinc-NMDAR interaction in neuronal function and human health. PMID:27288002

  7. Radiation damage test of position sensitive silicon detectors

    International Nuclear Information System (INIS)

    A study of radiation damage of position sensitive silicon detectors (PSDs), for use as a position monitor of high energy heavy ion beams, was carried out. It is revealed that the position linearity of the standard PSD is strongly affected even by an absorbed dose around 100 Gy. The reason of the distortion of position linearity was considered to be a positive charge build-up in the SiO2 layer covering the PSD. To overcome the problem, new types of PSDs have been developed raising impurity density in the resistive layer and removing the SiO2 layer. A PSD with a distortion of less than 100 μm over an effective area of 13 mm x 13 mm is obtained which is usable as a heavy ion beam monitor. (orig.)

  8. Postnatal manganese exposure does not alter dopamine autoreceptor sensitivity in adult and adolescent male rats.

    Science.gov (United States)

    McDougall, Sanders A; Mohd-Yusof, Alena; Kaplan, Graham J; Abdulla, Zuhair I; Lee, Ryan J; Crawford, Cynthia A

    2013-04-15

    Administering manganese chloride (Mn) to rats on postnatal day (PD) 1-21 causes long-term reductions in dopamine transporter levels in the dorsal striatum, as well as a persistent increase in D1 and D2 receptor concentrations. Whether dopamine autoreceptors change in number or sensitivity is uncertain, although D2S receptors, which may be presynaptic in origin, are elevated in Mn-exposed rats. The purpose of this study was to determine if early Mn exposure causes long-term changes in dopamine autoreceptor sensitivity that persist into adolescence and adulthood. To this end, male rats were exposed to Mn on PD 1-21 and autoreceptor functioning was tested 7 or 70 days later by measuring (a) dopamine synthesis (i.e., DOPA accumulation) in the dorsal striatum after quinpirole or haloperidol treatment and (b) behavioral responsiveness after low-dose apomorphine treatment. Results showed that low doses (i.e., "autoreceptor" doses) of apomorphine (0.06 and 0.12 mg/kg) decreased the locomotor activity of adolescent and adult rats, while higher doses increased locomotion. The dopamine synthesis experiment also produced classic autoreceptor effects, because quinpirole decreased dorsal striatal DOPA accumulation; whereas, haloperidol increased DOPA levels in control rats, but not in rats given the nerve impulse inhibitor γ-butyrolactone. Importantly, early Mn exposure did not alter autoreceptor sensitivity when assessed in early adolescence or adulthood. The lack of Mn-induced effects was evident in both the dopamine synthesis and behavioral experiments. When considered together with past studies, it is clear that early Mn exposure alters the functioning of various dopaminergic presynaptic mechanisms, while dopamine autoreceptors remain unimpaired. PMID:23458069

  9. Enhancement of radiation sensitivity by erlotinib and celecoxib in A549 human lung cancer cell line

    International Nuclear Information System (INIS)

    Objective: To investigate the role of epidermal growth factor receptor and cyclooxygenase-2 pathways in the erlotinib and celecoxib enhanced radiation sensitivity in A549 human lung cancer cell line. Methods: IC20 of erlotinib and celecoxib on in A549 human lung cancer cells was measured by MTT assay, Clonogenic assays were used to evaluate the antitumor effects of the drugs and X-irradiation. Flow cytometry was used to assess the apoptosis and cell cycle alteration, and Western blot was used for the detection of Akt and phospho-Akt.Results Both erlotinib and celecoxib could inhibit the proliferation of A549 cells in vitro in a dose-dependent manner and their values of IC20 were (5.15 ± 0.14) and (40.32 ± 1.26) μmol/L, respectively. For radiation survival,the values of Dq, D0, SF2 of the combination of two drugs were lower than those of either drug (t=6.62, P<0.05). The SER of celecoxib, erlotinib and their combination were 1.299, 1.503 and 2.217, respectively. Flow cytometry assay showed that both celecoxib and erlotinib could enhance radiation-induced G0/G1 arrest, reduce the cell number in S phase, and enhance radiation-induced apoptosis, especially for the combination of drugs. Western blot assay showed that the expressions of Akt protein were similar in all groups. However, pAkt expression was suppressed by erlotinib and celecoxib, but promoted by radiation. pAkt had the lowest expression in the radiated cells with the treatment of two drugs (t=4.89, P<0.05). Conclusions: The erlotinib and/or celecoxib could enhance radiosensitivity probably by increasing cell apoptosis and reducing the number of S-phase cells with low radiosensitivity. (authors)

  10. Studies on radiation-sensitive nonsilver halide materials, (1)

    International Nuclear Information System (INIS)

    In order to discover new radiation-sensitive nonsilver halide materials, the coloration based on the formation of Stenhouse salts was studied in the following three systems: (a) furfural-amine/HCl aq/methanol solution, (b) furfural-amine/polyhalogenide/PMMA matrix, (c) furfural-amine/PVC matrix. Firstly, forty-five aromatic amines were surveyed to find out the amines suitable for the color precursors (reactant from furfural and amine) in the system (a). As a result, the five amines, which gave the precursors in good yields by the reaction with furfural, were selected: m-nitroaniline, N-methylaniline, m-methyl-N-methylaniline, aniline, and o-methoxyaniline. Secondly, the coloration induced by electron beam bombardment was studied in the systems (b) and (c) containing the color precursors (the reactants from these amines and furfural). Although the PMMA films containing the color precursors and polyhalogenides were sensitive to electron beam, they were not stable when standing under daylight at room temperature. The PVC films containing the color precursors were very stable and colored to reddish yellow (lambda sub(max) 498 - 545 nm) by electron beam bombardment. The PVC film containing N-methylaniline-furfural was the most sensitive and the increase in absorbance at 498 nm was 0.78 by electron beam bombardment of 60 kV - 7.5 x 10-7C/cm2. A good linear relationship existed between the degree of coloration and the amounts of electron beam bombardment in the range from 0 to 10-6C/cm2. (author)

  11. Influence of pretreatment with selenious yeast on radiation sensitivity

    International Nuclear Information System (INIS)

    The generation of free radical species as a result of radiation exposure is a well-known process. Protection against oxidative damage is possible by endogenous antioxidant defense (enzymatic and nonenzymatic components) but also by drug and dietary treatment. Among the enzymes, glutathione peroxidase (GSH-Px), copper-zinc-containing superoxide dismutase (CuZn SOD), manganese-containing superoxide dismutase (Mn SOD) and catalase (CAT) form the primary intracellular defense system. Nonenzymatic components which regulate autoxidative defense are: glutathione and other sulfhydryl, metals, metalloproteins and antioxidant vitamins. Selenium as a constituent of glutathione peroxidase (GSH-Px) and selenium-containing proteins play an important role in radiosensitivity of the cells. Changes in nutritional Se status would alter the cellular Se concentration, which in turn would result in the loss or restoration of GSH-PX activity. Although it is now evident that a decrease of the selenium and GSH-PX levels can cause radiosensitization, it is less clear whether an increased level can afford radioprotection. Thus, the aim of this work was to study the effect of selenious yeast ingestion on the Se contents in blood, hair, and feces of rats and its effect on radiosensitivity. 3 refs., 1 fig., 3 tabs

  12. Are biological effects of space radiation really altered under the microgravity environment?

    Science.gov (United States)

    Yatagai, Fumio; Ishioka, Noriaki

    2014-10-01

    Two major factors of space environment are space radiation and microgravity. It is generally considered that a high level of ionizing radiation (IR) in space has an influence on living organisms including humans; therefore, the possible alteration of space-radiation influences by the microgravity environment is of great concern. In fact, examination of such a possibility has been extensively conducted since the early days of space experiments, suggesting a possible synergistic effect of radiation and microgravity in some experiments but a negative observation in others. Because these complicated results remain not well understood, we propose a solution to this problem. Gene expression analysis is one of the solutions to the problem. In fact, gene expression may be changed by microgravity, and further modification may be possible through IR. This result could reveal an interactive effect of both factors on the cellular responses, which could in turn reveal whether the human-health abnormalities expected under the microgravity environment can be altered by space radiation. We believe that this is a new aspect in the study of the interactive effect of radiation and microgravity. However, further improvements in space experimental technologies are required for future studies.

  13. Interleukin 1 beta initially sensitizes and subsequently protects murine intestinal stem cells exposed to photon radiation

    International Nuclear Information System (INIS)

    Interleukin 1 (IL-1) has been shown to prevent early bone marrow-related death following total-body irradiation, by protecting hematopoietic stem cells and speeding marrow repopulation. This study assesses the effect of IL-1 on the radiation response of the intestinal mucosal stem cell, a nonhematopoietic normal cell relevant to clinical radiation therapy. As observed with bone marrow, administration of human recombinant IL-1 beta (4 micrograms/kg) to C3H/Km mice 20 h prior to total-body irradiation modestly protected duodenal crypt cells. In contrast to bone marrow, IL-1 given 4 or 8 h before radiation sensitized intestinal crypt cells. IL-1 exposure did not substantially alter the slope of the crypt cell survival curve but did affect the shoulder: the X-ray survival curve was offset to the right by 1.01 +/- 0.06 Gy when IL-1 was given 20 h earlier and by 1.28 +/- 0.08 Gy to the left at the 4-h interval. Protection was greatest when IL-1 was administered 20 h before irradiation, but minimal effects persisted as long as 7 days after a single injection. The magnitude of radioprotection at 20 h or of radiosensitization at 4 h increased rapidly as IL-1 dose increased from 0 to 4 micrograms/kg. However, doses ranging from 10 to 100 micrograms/kg produced no further difference in radiation response. Animals treated with saline or IL-1 had similar core temperatures from 4 to 24 h after administration, suggesting that thermal changes were not responsible for either sensitization or protection. Mice irradiated 20 h after IL-1 had significantly greater crypt cell survival than saline-treated irradiated controls at all assay times, which ranged from 54 to 126 h following irradiation. The intervals to maximum crypt depopulation and initiation of repopulation were identical in both saline- and IL-1-treated groups

  14. Analysis of unstable chromosome alterations frequency induced by neutron-gamma mixed field radiation

    International Nuclear Information System (INIS)

    Nowadays monitoring chromosome alterations in peripheral blood lymphocytes have been used to access the radiation absorbed dose in individuals exposed accidental or occupationally to gamma radiation. However there are not many studies based on the effects of mixed field neutron-gamma. The radiobiology of neutrons has great importance because in nuclear factories worldwide there are several hundred thousand individuals monitored as potentially receiving doses of neutron. In this paper it was observed the frequencies of unstable chromosome alterations induced by a gamma-neutron mixed field. Blood was obtained from one healthy donor and exposed to mixed field neutron-gamma sources 241AmBe (20 Ci) at the Neutron Calibration Laboratory (NCL-CRCN/NE-PE-Brazil). The chromosomes were observed at metaphase, following colcemid accumulation and 1000 well-spread metaphases were analyzed for the presence of chromosome alterations by two experienced scorers. The results suggest that there is the possibility of a directly proportional relationship between absorbed dose of neutron-gamma mixed field radiation and the frequency of unstable chromosome alterations analyzed in this paper. (author)

  15. Effect of pre-existing thermal sensitization on the radiation induced sensitization in type 304 stainless steels

    International Nuclear Information System (INIS)

    It is generally recognized that radiation induced sensitization plays an important role in initiating irradiation assisted stress corrosion cracking (IASCC) of austenitic stainless steels in reactor core internal of light water reactor. However, the synergism between radiation sensitization and prior thermal sensitization is unclear. This situation is likely to occur in most welded core internal structures subjected to neutron irradiation. In this study, the effect of prior thermal treatment on radiation sensitization were investigated on proton irradiated Type 304 stainless steel (SS) of initially as-received (AR) and thermal-sensitized (SEN) conditions. The Cr depletion profiles were measured by field emission gun transmission electron microscopy/energy dispersive spectroscopy (FEGTEM/EDS), and were calculated by a radiation induced segregation (RIS) model. The different initial conditions were input in the RIS model calculations. For the as-received condition, the initial Cr profile was modeled by a uniform concentration distribution. For the initially thermal-sensitized condition, the wider Cr depletion profile measured by FEGTEM/EDS was input as the initial condition. The results showed that radiation sensitization is characterized by a very narrow Cr depleted zone. The Cr content at grain boundary tends to be lower as radiation dose increases. Comparing with the non-sensitized (as-received) specimens with the same dosage, the grain boundary Cr content without prior sensitization is higher than that with sensitization pre-treatment. The deeper grain boundary Cr concentration of irradiated thermally sensitized sample is induced not only from proton irradiation effect, but also resulted from pre-existing Cr depletion

  16. Chronic Intake of Japanese Sake Mediates Radiation-Induced Metabolic Alterations in Mouse Liver.

    Directory of Open Access Journals (Sweden)

    Tetsuo Nakajima

    Full Text Available Sake is a traditional Japanese alcoholic beverage that is gaining popularity worldwide. Although sake is reported to have beneficial health effects, it is not known whether chronic sake consumption modulates health risks due to radiation exposure or other factors. Here, the effects of chronic administration of sake on radiation-induced metabolic alterations in the livers of mice were evaluated. Sake (junmai-shu was administered daily to female mice (C3H/He for one month, and the mice were exposed to fractionated doses of X-rays (0.75 Gy/day for the last four days of the sake administration period. For comparative analysis, a group of mice were administered 15% (v/v ethanol in water instead of sake. Metabolites in the liver were analyzed by capillary electrophoresis-time-of-flight mass spectrometry one day following the last exposure to radiation. The metabolite profiles of mice chronically administered sake in combination with radiation showed marked changes in purine, pyrimidine, and glutathione (GSH metabolism, which were only partially altered by radiation or sake administration alone. Notably, the changes in GSH metabolism were not observed in mice treated with radiation following chronic administration of 15% ethanol in water. Changes in several metabolites, including methionine and valine, were induced by radiation alone, but were not detected in the livers of mice who received chronic administration of sake. In addition, the chronic administration of sake increased the level of serum triglycerides, although radiation exposure suppressed this increase. Taken together, the present findings suggest that chronic sake consumption promotes GSH metabolism and anti-oxidative activities in the liver, and thereby may contribute to minimizing the adverse effects associated with radiation.

  17. Ultraviolet-B radiation alters phenolic salicylate and flavenoid composition of Populus trichocarpa leaves

    Energy Technology Data Exchange (ETDEWEB)

    Warren, J. M. [USDA Forest Service, Forestry Science Laboratory, Corwallis, OR (United States); Bassman, J. H. [Washington State Univ., Dept. of Natural Resources Sciences, Pullman, WA (United States); Fellman, J. K.; Mattinson, D. S. [Washington State Univ., Dept. of Horticulture and Landscape Architecture, Pullman, WA (United States); Eigenbrode, S. [Idaho Univ., Dept. of Plant, Soil and Entomological Sciences, Moscow, ID (United States)

    2003-06-01

    Foliar phenolic composition of field- and greenhouse-grown black cottonwood was studied by subjecting samples to near zero, ambient and twice-ambient concentrations of biologically effective ultraviolet-B radiation. Phenolic compounds were extracted after three months, separated by liquid chromatography and identified and quantified by diode-array spectrometry and mass spectrometry. Phenolic compounds that were found to have increased in response to UV-B radiation were flavonoids, although increasing the level of radiation to ambient and twice ambient levels did not result in further flavonoid accumulation in either greenhouse or field samples. There was, however, an increase in salicortin, a non-flavonoid glycoside, and a salicylates that is important in plant-herbivore-predator relationships. It was concluded that enhanced solar UV-B radiation has the capacity to significantly alter trophic structure in some ecosystems by stimulating specific phenolic compounds. 74 refs., 1 tab., 6 figs.

  18. Inheritance of induction radiation sensitivity of space flight environments and γ-radiation on rice

    Science.gov (United States)

    Xu, J.; Wang, J.; Wei, L.; Li, Z.; Sun, Y.

    There are many factors affecting living things during space flight, such as microgravity, cosmic radiation, etc. A large number of plant mutants have been obtained after space flight on satellite in China in the last decade and some commercial crop varieties were released. However, little consideration has so far been given to the genetic mechanisms underlying sensitivity of plant seeds to space flight environments. To reveal the genetic mechanisms associated with induction radiation sensitivity (IRS), a set of 226 recombination inbred lines (RILs) derived from Lemont (japonica)/ Teqing (indica) F13, were analyzed using 164 well-distributed DNA markers and assayed for the traits related to IRS including rate of survival seedling (RSS), seedling height (SH), seed setting rate (SSR) and total physiological damage (TPD) in replicated trials after space flight on Chinese Shenzhou IV Spacecraft andγ -radiation treatment (35000 rad) on the ground in 2002. Seedling growth of Lemont was accelerated after space flight with the SH of 116.2% of ground control while growth suppression was happened for Teqing with the SH of 85.7% of ground control. γ -radiation treatment resulted in significant decrease in all tested traits for the two parents, indicating space flight and γ -radiation treatment had different biological effects on the two parents. Significant differences were detected among the RILs for their responses to space flight environments and γ -radiation, reflected as the difference in the four tested traits. Space flight resulted in stimulation on growth for 57.1% lines whileγ -radiation had suppression on growth for most lines. Seventeen putative main-effect QTLs was identified for the four traits related to IRS under space flight and γ -radiation, which totally explained significant portions of the total trait variation (4.4% for RSS, 27.2% for SH, 4% for SSR and 15.8% for TPD for space flight; 10.4% for RSS, 15.1% for SH, 8.2% for SSR and 6.1% for TPD for

  19. Protective effect of flax seed oil against radiation induced hematological alterations in mammals

    International Nuclear Information System (INIS)

    Human beings are exposed to ionizing and non ionizing radiation from natural as well as manmade sources. Ionizing radiations are one of the predominant exogenous factors that have deleterious consequences to human life. Exposure to ionizing radiations damages the hematopoietic, gastrointestinal or central nervous systems, depending on radiation dose. Hence, there is an urgent need to prevent such deleterious effects caused due to ionizing radiations. Chemical protection involves the use of synthetic and natural products against planned radiation exposure. Medicinal plants are rich in antioxidants and their chemical constituents may be the potential source for radioprotective agents. Linum usitatissimum plant (family: Linaceae), source of flaxseed oil (FSO), is well known for its anticarcinogenic, antidiabetic, cardioprotector, antiulcer properties owing to the presence of various phytochemicals. The present study has been focused to find out the preventive action of flaxseed oil against radiation induced hematological and biochemical lesions in mammals. For this purpose, FSO (50μL/animal/day) was orally administered to Swiss albino mice for five days, prior to 6 Gy gamma radiation exposure. The animals were sacrificed on 1st, 3rd, 7th, 15th and 30th day after irradiation. Radiation treated control group exhibited significant reduction in erythrocytes count, hemoglobin content, hematocrit value and total WBC count in peripheral blood. In contrast, pretreatment with FSO significantly increased all these blood constituents. Further, the antioxidant parameters such as reduced glutathione, catalase, and superoxide dismutase showed a significant elevation in FSO pretreated group which were reduced in irradiated control group. Similarly, radiation induced increase lipid peroxidation in blood was significantly inhibited after FSO treatment. The present results indicate that the flaxseed oil has the ability to debilitate the radiation induced adverse alterations in the

  20. Radiation-induced alterations in mitochondrial protein synthesis in rat liver

    International Nuclear Information System (INIS)

    The incorporation of 14C-labeled leucine into hepatic mitochondrial proteins in vivo is enhanced up to 48 hr following whole-body X irradiation. A similar increase in labeling is also observed with liver slices from irradiated rats, incubated in vitro, but not with isolated liver mitochondria. Evidence is presented to indicate that these divergent labeling data may be related to the dual origin of the mitochondrial proteins and differences in the radiation-induced effects on the synthesis of mitochondrial proteins of intra- and extra-mitochondrial origin. The increased labeling observed in vivo does not denote a stimulation of mitochondrial protein synthesis but merely reflects a contraction of the free leucine pool of mitochondria. The possible significance of the radiation-induced alterations in the pattern of mitochondrial protein synthesis to the reported morphological alterations of this organelle is discussed

  1. The alteration of pain sensitivity at disease-specific acupuncture points in premenstrual syndrome.

    Science.gov (United States)

    Chae, Younbyoung; Kim, Hee-Young; Lee, Hwa-Jin; Park, Hi-Joon; Hahm, Dae-Hyun; An, Kyungeh; Lee, Hyejung

    2007-04-01

    Acupuncture points (APs) are well known to be small regions of local or referred pain that are more sensitive than surrounding tissue. Based on bibliographical and clinical data, specific conditions are commonly believed to change the pain sensitivity at corresponding APs. The aim of the present study was to investigate whether the pressure pain threshold (PPT) of specific APs is associated with the severity of premenstrual syndrome. The 46 participants were female students attending a middle school. Premenstrual syndrome (PMS) was measured using a structured questionnaire, the menstruation distress questionnaire (MDQ). High PMS (HP) and low PMS (LP) groups were divided based on their MDQ scores. The PPTs at sites in the leg (the APs SP6, GB39, and LR3 and a non-AP 2-cm anterior to SP6) and in the arm (the APs PC6, TE5, and LI4 and a non-AP 2-cm proximal to PC6) were measured using an algometer. The PPT of the HP group at SP6 was significantly lower than that of the LP group (13.50 +/- 0.73 vs. 16.30 +/- 0.66 kilopascals, P < 0.05), but not at other APs or at non-APs. The findings of our study support the hypothesis that the alteration of pain threshold at specific APs is associated with the severity of corresponding diseases. Further studies are needed to determine whether an observation of pain sensitivity at the APs could be used as an adjunctive tool for the diagnosis of a clinical problem. PMID:17378970

  2. Radiation sensitivity of memory chip module of an ID card

    Energy Technology Data Exchange (ETDEWEB)

    Mathur, V.K. [Naval Surface Warfare Center, Carderock Division, Bethesda MD 20817 (United States)]. E-mail: veerendra.mathur@navy.mil; Barkyoumb, J.H. [Naval Surface Warfare Center, Carderock Division, Bethesda MD 20817 (United States); Yukihara, E.G. [Department of Physics, Oklahoma State University, Stillwater, OK 74078 (United States); Goeksu, H.Y. [GSF- National Research Center for Environment and Health, D-85764 Neuherberg (Germany)

    2007-01-15

    The utility of ID card chip modules to function as a radiation dosimeter is investigated. Specifically the thermoluminescence (TL) and optically stimulated luminescence (OSL) of a sampling of chip modules are measured over the range of 0.4-12Gy. Both infrared (830nm) from a laser diode and blue light (470nm) from LEDs were used to perform the OSL measurements. The TL measurements showed a linear dose-response relationship, but the TL suffered from a large zero-dose signal in the unirradiated samples and dose regeneration with time after heating the chip modules. The OSL measurements also showed a linear dose-response, but did not exhibit a zero-dose signal or regeneration. Performing the infrared OSL measurements at a temperature of 140{sup -}bar C may improve the dose sensitivity to 0.15Gy, but the dose-response is supralinear in the dose range investigated. Curve fitting of infrared and blue stimulated luminescence curves showed that both exhibit a fast and a slow component. Thermal stability studies indicates the presence of a component that decays in the first hour of irradiation, and a component that is stable at least during the period of investigation (up to 10h). This stable component is more appropriate for dosimetry purposes.

  3. Solar Radiation Alters Toxicity of Carbofuran: Evidence from Empirical Trials with Duttaphyrnus melanostictus

    OpenAIRE

    M. R. Wijesinghe; B.A.D.M.C. Jayatillake; W. D. Ratnassoriya

    2011-01-01

    In the present study we investigated the potential of natural solar radiation to alter the toxicity of a commonly used carbamate pesticide, carbofuran, on tadpoles of the Common Asian Toad Duttaphrynus melanostictus. A single exposure trial was conducted over 96 hrs with three concentrations (150, 250 and 500 µgl-1) of photo-irradiated and non-irradiated carbofuran. Results show that photo-irradiation markedly reduced the toxicity of carbofuran as evident by its effects on three end points, i...

  4. Motility alterations in celiac disease and non-celiac gluten sensitivity.

    Science.gov (United States)

    Pinto-Sanchez, Maria Ines; Bercik, Premysl; Verdu, Elena F

    2015-01-01

    Regulation of gut motility is complex and involves neuromuscular, immune and environmental mechanisms. It is well established that patients with celiac disease (CD) often display gut dysmotility. Studies have shown the presence of disturbed esophageal motility, altered gastric emptying, and dysmotility of the small intestine, gallbladder and colon in untreated CD. Most of these motor abnormalities resolve after a strict gluten-free diet, suggesting that mechanisms related to the inflammatory condition and disease process are responsible for the motor dysfunction. Motility abnormalities are also a hallmark of functional bowel disorders such as irritable bowel syndrome (IBS), where it has been proposed as underlying mechanism for symptom generation (diarrhea, constipation, bloating). Non-celiac gluten sensitivity (NCGS) is a poorly defined entity, mostly self-diagnosed, that presents clinically with IBS symptoms in the absence of specific celiac markers. Patients with NCGS are believed to react symptomatically to wheat components, and some studies have proposed the presence of low-grade inflammation in these patients. There is little information regarding the functional characterization of these patients before and after a gluten-free diet. A study suggested the presence of altered gastrointestinal transit in NCGS patients who also have a high prevalence of nonspecific anti-gliadin antibodies. Results of an ongoing clinical study in NCGS patients with positive anti-gliadin antibodies before and after a gluten-free diet will be discussed. Elucidating the mechanisms for symptom generation in NCGS patients is important to find new therapeutic alternatives to the burden of imposing a strict gluten-free diet in patients who do not have CD. PMID:25925923

  5. Initial impacts of altered UVB radiation on plant growth and decomposition in shortgrass steppe

    Science.gov (United States)

    King, Jennifer Y.; Milchunas, Daniel G.; Mosier, Arvin R.; Moore, John C.; Quirk, Meghan H.; Morgan, Jack A.; Slusser, James R.

    2003-11-01

    We initiated a study in winter 2000 in a Colorado shortgrass steppe to investigate effects of altered ultraviolet-B (UVB) radiation and altered precipitation on plant growth, plant tissue decomposition, and litter faunal activity. In the field, open-air structures were constructed of solid plastic sheet material that either passed all wavelengths of solar radiation or passed only wavelengths greater than 400 nm (UVB =280-315 nm). Preliminary results indicate decreases in warm-season grass production under UVB radiation and drought conditions. Analysis of fiber constituents shows some significant seasonal and UVB treatment effects. The results of in vitro digestible dry matter analyses show significantly higher digestibility with UVB. Simulated grazing increased plant production, but there were no UVB by grazing interactions. Litter decomposition was affected by UVB exposure, the CO2 growing conditions, and precipitation level. Under dry conditions, UVB radiation tended to increase litter decomposition, as measured by mass loss. There were no clear initial effects of UVB treatment on soluble and fiber constituents of litter. Exclusion of UVB resulted in reduced fungal hyphae counts in ambient CO2-grown litter collected in fall 2002. Preliminary results indicate that litter arthropod density was lower with exposure to UVB and also lower under drought conditions.

  6. Apigenin ameliorates gamma radiation-induced cytogenetic alterations in cultured human blood lymphocytes.

    Science.gov (United States)

    Begum, Naziya; Prasad, N Rajendra; Kanimozhi, G; Hasan, Annie Q

    2012-08-30

    The aim of the present study was to assess the protective effect of apigenin, a dietary flavone, against cytogenetic alterations in human peripheral blood lymphocytes (HPBL) induced by Cobalt-60 radiation (3Gy). Results of MTT [3-(4, 5-dimethyl-2-thiaozolyl)-2,5-diphenyl-2H tetrazolium bromide] assay revealed that 37.2μM of apigenin was found to be non-toxic in HPBL. At this dose (37.2μM) of apigenin, the LD(50) radiation dose of HPBL increased from 2.9Gy to 3.4Gy, which resulted in a DMF of 1.17. Apigenin (37.2μM) treatment 1h before irradiation significantly (p<0.05) reduced DNA damage in irradiated HPBL as measured by comet assay (% tail DNA, tail length, tail moment, and olive tail moment). Moreover, apigenin treatment significantly decreased the frequencies of dicentric (DC), acentric fragments (AF), and acentric rings (AR) in irradiated HPBL. Apigenin pretreatment also reduced the radiation-induced CBMN (cytokinesis blocked micronuclei) anomalies such as micronuclei (MNi), nucleoplasmic bridges (NPB) and nuclear buds (NBUD) in HPBL. These results also showed that there was a significant correlation between NPB and DC frequencies and MNi and AF+AR. Treatment with apigenin alone had no significant effect on DNA damage and chromosomal aberrations in HPBL. Thus, the current studies indicate that apigenin protects HPBL from radiation-induced cytogenetic alterations. PMID:22516036

  7. Alteration of radiation response by two tyrosine kinase inhibitors: STI571 (Glivec) and BIBW 2992

    International Nuclear Information System (INIS)

    Concurrent chemo-radiation is one of the main weapon in the treatment of cancer. The targeted therapies may act on the mechanisms of tumor resistance to radiation and are therefore very promising in combination with radiotherapy. The STI571 (imatinib or Gleevec) inhibits specifically the Bcr-Abl tyrosine kinase. It leads to radiosensitization in K562 chronic myeloid leukemia cell line by alterations of the cell cycle. The BIBW2992 is a selective inhibitor of EGFR and HER2. The BIBW 2992 shows cytotoxic and radiosensitizing effects on pancreatic adenocarcinoma cells BxPC3 and Capan-2, regardless of KRAS status. The mechanism underlying this radiosensitization is not unequivocal, involving both changes in the cell cycle and induction of mitotic death. Our results show that the combination of an inhibitor of tyrosine kinase with ionizing radiation may lead to a radiosensitization in vitro with mechanisms depending on the type of cell line. (author)

  8. Molecular alterations in childhood thyroid cancer after Chernobyl accident and low-dose radiation risk

    International Nuclear Information System (INIS)

    The linear no-threshold (LNT) model of radiation carcinogenesis has been used for evaluating the risk from radiation exposure. While the epidemiological studies have supported the LNT model at doses above 100 mGy, more uncertainties are still existed in the LNT model at low doses below 100 mGy. Thus, it is urged to clarify the molecular mechanisms underlying radiation carcinogenesis. After the Chernobyl accident in 1986, significant amount of childhood thyroid cancer has emerged in the children living in the contaminated area. As the incidence of sporadic childhood thyroid cancer is very low, it is quite evident that those cancer cases have been induced by radiation exposure caused mainly by the intake of contaminated foods, such as milk. Because genetic alterations in childhood thyroid cancers have extensively been studied, it should provide a unique chance to understand the molecular mechanisms of radiation carcinogenesis. In a current review, molecular signatures obtained from the molecular studies of childhood thyroid cancer after Chernobyl accident have been overviewed, and new roles of radiation exposure in thyroid carcinogenesis will be discussed. (author)

  9. Studying the sensitivity of personnel neutron dosemeter PDM-303 to high-energy neutron radiation

    International Nuclear Information System (INIS)

    The sensitivity of the PDM-303 personnel neutron dosemeter to high-energy radiation behind the U-70 accelerator shield and neutron calibration fields of IHEP is investigated. It is found that this dosemeter has high sensitivity to high-energy neutrons. The fact requires introduction of correcting calibration coefficients in the case of its application in conditions of the U-70 accelerator radiation

  10. Carcinogenic alterations in murine liver, lung, and uterine tumors induced by in utero exposure to ionizing radiation.

    Science.gov (United States)

    Lumniczky, K; Antal, S; Unger, E; Wunderlich, L; Hidvégi, E J; Sáfrány, G

    1998-02-01

    The atomic bombing of Hiroshima and Nagasaki and the nuclear accident at Chernobyl raised the question of prenatal sensitivity to ionizing radiation-induced cancer. In this study, mice were exposed to single doses of gamma-radiation (0.2-2.0 Gy) at different embryonic stages. The tumor incidence increased with dose from 15% in control mice to 35% in mice irradiated with 2.0 Gy on 18 d of prenatal life. Various oncogenic events were investigated in lymphoid, liver, lung, and uterine tumors. We observed threefold to fivefold increases in myc expression in 25% of the lymphomas, and the expression of Ha-ras and p53 genes decreased in 40% and 60% of the lung tumors by twofold to fivefold. Point mutations were tissue specific: Ha-ras codon 61 mutations were found in about 40% of the liver adenocarcinomas, Ki-ras codon 12 mutations in about 17% of lung tumors, and p53 mutations in about 15% of the lymphomas. Amplification and rearrangement of the p53, myc, and Ha-, Ki- and N-ras genes were not detected. Loss of heterozygosity on chromosome 4 at the multiple tumor suppressor 1 and 2 genes was observed in all types of malignancies. Allelic losses on chromosome 11 at the p53 locus were found in lymphoid, liver, and lung tumors, but they were absent from uterine tumors. Multiple oncogenic changes were often detected. The frequency of carcinogenic alterations was similar in spontaneous and radiation-induced lymphoid, liver, and uterine tumors. In radiation-induced lung adenocarcinomas, however, the incidences of many oncogenic changes were different from those found in their spontaneous counterparts. This suggests that different oncogenic pathways are activated during spontaneous and in utero gamma-radiation-induced murine lung carcinogenesis. PMID:9496910

  11. Influence of TRPV1 on diabetes-induced alterations in thermal pain sensitivity

    Directory of Open Access Journals (Sweden)

    Pauza Mary E

    2008-03-01

    Full Text Available Abstract A common complication associated with diabetes is painful or painless diabetic peripheral neuropathy (DPN. The mechanisms and determinants responsible for these peripheral neuropathies are poorly understood. Using both streptozotocin (STZ-induced and transgene-mediated murine models of type 1 diabetes (T1D, we demonstrate that Transient Receptor Potential Vanilloid 1 (TRPV1 expression varies with the neuropathic phenotype. We have found that both STZ- and transgene-mediated T1D are associated with two distinct phases of thermal pain sensitivity that parallel changes in TRPV1 as determined by paw withdrawal latency (PWL. An early phase of hyperalgesia and a late phase of hypoalgesia are evident. TRPV1-mediated whole cell currents are larger and smaller in dorsal root ganglion (DRG neurons collected from hyperalgesic and hypoalgesic mice. Resiniferatoxin (RTX binding, a measure of TRPV1 expression is increased and decreased in DRG and paw skin of hyperalgesic and hypoalgesic mice, respectively. Immunohistochemical labeling of spinal cord lamina I and II, dorsal root ganglion (DRG, and paw skin from hyperalgesic and hypoalgesic mice reveal increased and decreased TRPV1 expression, respectively. A role for TRPV1 in thermal DPN is further suggested by the failure of STZ treatment to influence thermal nociception in TRPV1 deficient mice. These findings demonstrate that altered TRPV1 expression and function contribute to diabetes-induced changes in thermal perception.

  12. Repeated restraint stress alters sensitivity to the social consequences of ethanol differentially in early and late adolescent rats.

    OpenAIRE

    Varlinskaya, Elena I.; Truxell, Eric M.; Spear, Linda P.

    2013-01-01

    In rats, considerable differences in the social consequences of acute ethanol are seen across ontogeny, with adolescents being more sensitive to low dose ethanol-induced social facilitation and less sensitive to the social inhibition evident at higher ethanol doses relative to adults. Stressor exposure induces social anxiety-like behavior, indexed via decreases in social preference, and alters responsiveness to the social consequences of acute ethanol by enhancing ethanol-associated social fa...

  13. Ionizing radiation alters neuronal excitability in hippocampal slices of the guinea pig

    International Nuclear Information System (INIS)

    To investigate the effects of ionizing radiation on an isolated neuronal network without complicating systemic factors, slices of hippocampus from the guinea pig were isolated and studied in vitro. Slices were irradiated with a 60Co source and compared to paired, sham-irradiated controls. Electrophysiological activity in the CA 1 population of pyramidal cells was evoked by stimulation of the stratum radiatum. Analysis of the somatic and dendritic responses suggested sites of radiation damage. Orthodromically evoked activity was significantly decreased in slices receiving greater than 75 Gy gamma radiation. The effects were dose and dose-rate dependent. At 20 Gy/min, doses of 50 Gy and greater produced synaptic impairment while doses of 75 Gy and greater also produced postsynaptic damage (i.e., the ability of the synaptic response to generate an action potential). A lower dose rate, 5 Gy/min, reduced the sensitivity of synaptic damage to radiation exposure; synaptic impairment required a dose of 100 Gy or greater at the lower dose rate. In contrast, postsynaptic damage was not sensitive to dose rate. This study demonstrates that ionizing radiation can directly affect the integrated functional activity of neurons

  14. Mesenchymal stem cells are sensitive to treatment with kinase inhibitors and ionizing radiation

    International Nuclear Information System (INIS)

    Mesenchymal stem cells (MSCs) can regenerate damaged tissues and may therefore be of importance for normal tissue repair after cancer treatment. Small molecule receptor kinase inhibitors (RKIs) have recently been introduced into cancer treatment. However, the influence of these drugs - particularly in combination with radiotherapy - on the survival of MSCs is largely unknown. The sensitivity of human primary MSCs from healthy volunteers and primary human fibroblast cells to small molecule kinase inhibitors of the vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF) and transforming growth factor β (TGFβ) receptors, as well to inhibitors of c-Kit, was examined in combination with ionizing radiation (IR); cell survival and proliferation were assessed. Expression patterns of different kinase receptors and ligands were investigated using gene arrays. MSCs were highly sensitive to the tyrosine kinase inhibitors SU14816 (imatinib) and SU11657 (sunitinib), but showed only moderate sensitivity to the selective TGFβ receptor 1 inhibitor LY2109761. Primary adult human fibroblasts were comparably resistant to all three inhibitors. The addition of IR had an additive or supra-additive effect in the MSCs, but this was not the case for differentiated fibroblasts. Proliferation was markedly reduced in MSCs following kinase inhibition, both with and without IR. Gene expression analysis revealed high levels of the PDGF α and β receptors, and lower levels of the TGFβ receptor 2 and Abl kinase. IR did not alter the expression of kinase receptors or their respective ligands in either MSCs or adult fibroblasts. These data show that MSCs are highly sensitive to RKIs and combination treatments incorporating IR. Expression analyses suggest that high levels of PDGF receptors may contribute to this effect. (orig.)

  15. A Modular High Sensitive Radiation Detector for Homel and Security and Post Event Applications

    International Nuclear Information System (INIS)

    A modular, high sensitive radiation monitoring system designed for the homeland security radiological requirements and radiological post event applications is presented. The prevention of undocumented and potentially threatening shipment of radioactive and nuclear materials is a problem at seaports, border crossings, rail yards, airports and similar locations that requires the use of sensitive radiation detectors. Furthermore; radiological events such as the Fukushima nuclear incident emphasize the need for sensitive detector for monitoring food and commercial products

  16. Toward the elucidation of factors concerning the individual difference of radiation sensitivity, and the reduction of radiation risks

    International Nuclear Information System (INIS)

    This article describes studies aiming at the title subject and contains 2 topics of genetic and non-genetic factors modifying the radiation sensitivity. The ultimate purposes of those studies are the introduction of individual weighting factor to correct the individual differences of the sensitivity (IDS) and the practical control of the sensitivity-concerned factors, in the field of medical exposure. For genetic factors, described are studies on factors modifying the sensitivity at DNA repair and on the control of the sensitivity through the DNA repairing factors. The former, using cultured cells, aims at identifying protein (gene) of possible biomarker for IDS in non-homologous end-joining (NHEJ), an important mechanism in repairing the double strand break of DNA. Ku protein is found as the candidate. The latter has revealed that cells lacking Artemis, XRCC4 or MDC1 gene are highly sensitive, and are planning to suppress Artemis activity artificially, which may lead to the reduction of radiation cancer formation due to the death of highly sensitive cells. For non-genetic factors, described are studies on the life habits modifying the sensitivity, on the control of the sensitivity through the radiation-induced adaptive response and with steroid hormone. In the first, in mice treated with high-calorie diet and X-irradiation, a possible radiation response is suggested in the hepatic DNA-methylation and micro-RNA. Second, the combination of radiation adaptive response in the genome damage and restriction of diet ingestion is shown to lower the sensitivity of mice with use of C, Ne ion or X-ray irradiation. Third, in studies on the radiation-induced formation and condensation of breast cancer stem cells in the presence of progesterone, the hormone is found to produce micro-RNA molecules relating with the suppression of cellular senescence and repressed carcinogenesis with over-expression of apoptosis inhibitory molecules. (T.T.)

  17. Role of Rosemary leaves extract against radiation-induced hematological and biochemical alterations in mice

    Directory of Open Access Journals (Sweden)

    Acharya Garima S.

    2008-01-01

    Full Text Available The present paper is a study of the modulatory effect of Rosmarinus officinalis leaves extract on radiation-induced hematological and biochemical changes in Swiss albino mice. The dose reduction factor for the Rosemary extract against gamma rays was calculated 1.53 from LD50/30 values. The Rosemary extract was administered orally for 5 consecutive days prior to radiation exposure. The hematological and biochemical parameters were assessed from day 1 to 30 post-irradiation intervals. The total erythrocyte count, total leucocytes count, hemoglobin, and hematocrit values in the experimental group were found to be elevated as compared to the control group of mice. Furthermore, the Rosemary extract treatment enhanced reduced glutathione content in the liver and blood against radiation-induced depletion. Treatment with the plant extract brought a significant fall in the lipid peroxidation level, suggesting rosemary's role in protection against radiation-induced membrane and cellular damage. The results from the present study suggest a radio-protective effect of the Rosemary extract against radiation-induced hematological and biochemical alterations in mice.

  18. Radiation-induced alterations in murine lymphocyte homing patterns. I. Radiolabeling studies

    International Nuclear Information System (INIS)

    In vitro x-irradiation of 51Cr-labeled spleen, lymph node, bone marrow, or thymus cells was found to alter their subsequent in vivo distribution significantly in syngeneic BDF1 mice. Irradiated cells demonstrated an increased distribution to the liver and a significantly lower retention in the lungs. Cells going to the lymph nodes or Peyer's patches showed a significant exposure-dependent decrease in homing following irradiation. Irradiated lymph node cells homed in greater numbers to the spleen and bone marrow, while irradiated cells from other sources showed no preferential distribution to the same tissues. Sampling host tissues at various times after irradiation and injection did not demonstrate any return to normal patterns of distribution. The alterations in lymphocyte homing observed after in vitro irradiation appear to be due to the elimination of a selective population of lymphocytes or membrane alterations of viable cells, and the detection of these homing changes is in turn dependent upon the relative numbers of various lymphoid subpopulations which are obtained from different cell sources. Radiation-induced alterations in the normal homing patterns of lymphoid cells may thus be of considerable importance in the evaluation of subsequent functional assays in recipient animals

  19. Antiangiogenic Agent Might Upgrade tumor Cell Sensitivity to Ionizing Radiation

    International Nuclear Information System (INIS)

    The understanding of the fundamental role of angiogenesis and metastasis in cancer growth has led to tremendous interest in research regarding its regulatory mechanisms and clinical implications in the management of cancer. The present study was conducted to evaluate the influence of the angiogenic regulators modification on the tumor growth and the cell sensitivity to ionizing radiation targeting the improvement of cancer therapeutic protocols. Accordingly, the antiangiogenic activity of apigenin and selenium was tested in vitro via MTT assay. The action of Apigenin and or Selenium was examined in vivo by using a model of solid tumor carcinoma (EAC). The growth rate of solid tumor in all experimental groups was measured by Caliper. The irradiated mice were exposed to 6.5 Gy of gamma rays. Apigenin 50 mg/kg body weight and selenium 5 μg per mice were daily administrated for 14 consecutive days after tumor volume reached 1mm3. The angiogenic activators TNF-α (key cytokine) in spleen, serum MMP 2 and MMP 9, liver and tumor NO, the lipid peroxidation (LPx) and angiogenic inhibitor TIMP-1 in spleen as well as, antioxidant markers (CAT, SOD, GPX) in tumor and liver tissue and DNA fragmentation in splenocytes were estimated to monitor efficacy of Apigenin and selenium in cancer treatment strategy. All parameters were determined as a time course on days 16 and 22 after tumor volume reached 1mm3. The using of MTT assay on EAC cells shows inhibition in EAC cell proliferation after the incubation with apigenin and /or selenium. The administration of apigenin and /or selenium to mice bearing tumor and to irradiated mice bearing tumor reduce significantly the TNF-α expression, MMP 2,9 , NO , LPx level and increased the antioxidant enzymes (GPx , SOD and CAT) activities. The DNA fragmentation and the antiangiogenic factors TIMP-1 were significantly increased when compared with their values in mice bearing tumor or in irradiated mice bearing tumor. From the results obtained

  20. In vitro radiation induced alterations in heavy metals and metallothionein content in Plantago ovata Forsk.

    Science.gov (United States)

    Saha, Priyanka; Mishra, Debadutta; Chakraborty, Anindita; Sudarshan, Mathummal; Raychaudhuri, Sarmistha Sen

    2008-09-01

    Proton Induced X-ray emission (PIXE) and fluorescence-activated cell sorting (FACS) have been used to study the effects of gamma irradiation on heavy metal accumulation in callus tissue of Plantago ovata-an important cash crop of India. PIXE analysis revealed radiation-induced alteration in trace element profile during developmental stages of the callus of P. ovata. Subsequent experiments showed antagonism between Fe and Cu and also Cu and Zn and synergistic effect between Fe and Zn. FACS analysis showed significant induction of the metallothionein (MT) protein following gamma-irradiation, and maximum induction was noted at the 50-Gy absorbed dose. This indicated a progressive increment of MTs as a measure for protection against gamma-rays, to combat alteration in the homeostasis of heavy metals like Fe, Cu, Zn, and Mn. PMID:18493724

  1. Using synchrotron radiation angiography with a highly sensitive detector to identify impaired peripheral perfusion in rat pulmonary emphysema

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Hiromichi [University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575 (Japan); Matsushita, Shonosuke, E-mail: shomatsu@md.tsukuba.ac.jp [University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575 (Japan); Tsukuba University of Technology, Tsukuba, Ibaraki 305-8521 (Japan); Hyodo, Kazuyuki [High Energy Accelerator Research Organization, KEK, Tsukuba, Ibaraki 305-0801 (Japan); Sato, Yukio; Sakakibara, Yuzuru [University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575 (Japan)

    2013-03-01

    Synchrotron radiation angiography with a HARP detector made it possible to evaluate impaired pulmonary microcirculation in pulmonary emphysema by means of high sensitivity. Owing to limitations in spatial resolution and sensitivity, it is difficult for conventional angiography to detect minute changes of perfusion in diffuse lung diseases, including pulmonary emphysema (PE). However, a high-gain avalanche rushing amorphous photoconductor (HARP) detector can give high sensitivity to synchrotron radiation (SR) angiography. SR angiography with a HARP detector provides high spatial resolution and sensitivity in addition to time resolution owing to its angiographic nature. The purpose of this study was to investigate whether this SR angiography with a HARP detector could evaluate altered microcirculation in PE. Two groups of rats were used: group PE and group C (control). Transvenous SR angiography with a HARP detector was performed and histopathological findings were compared. Peak density of contrast material in peripheral lung was lower in group PE than group C (p < 0.01). The slope of the linear regression line in scattering diagrams was also lower in group PE than C (p < 0.05). The correlation between the slope and extent of PE in histopathology showed significant negative correlation (p < 0.05, r = 0.61). SR angiography with a HARP detector made it possible to identify impaired microcirculation in PE by means of its high spatial resolution and sensitivity.

  2. Using synchrotron radiation angiography with a highly sensitive detector to identify impaired peripheral perfusion in rat pulmonary emphysema

    International Nuclear Information System (INIS)

    Synchrotron radiation angiography with a HARP detector made it possible to evaluate impaired pulmonary microcirculation in pulmonary emphysema by means of high sensitivity. Owing to limitations in spatial resolution and sensitivity, it is difficult for conventional angiography to detect minute changes of perfusion in diffuse lung diseases, including pulmonary emphysema (PE). However, a high-gain avalanche rushing amorphous photoconductor (HARP) detector can give high sensitivity to synchrotron radiation (SR) angiography. SR angiography with a HARP detector provides high spatial resolution and sensitivity in addition to time resolution owing to its angiographic nature. The purpose of this study was to investigate whether this SR angiography with a HARP detector could evaluate altered microcirculation in PE. Two groups of rats were used: group PE and group C (control). Transvenous SR angiography with a HARP detector was performed and histopathological findings were compared. Peak density of contrast material in peripheral lung was lower in group PE than group C (p < 0.01). The slope of the linear regression line in scattering diagrams was also lower in group PE than C (p < 0.05). The correlation between the slope and extent of PE in histopathology showed significant negative correlation (p < 0.05, r = 0.61). SR angiography with a HARP detector made it possible to identify impaired microcirculation in PE by means of its high spatial resolution and sensitivity

  3. Individual radiation sensitivity (gender, age, genetic disposition). Consequences for radiation protection

    International Nuclear Information System (INIS)

    The effects of ionising radiation on human health is influenced by a number of physiological and molecular biological factors. This is also valid for the causation of stochastic radiation effects especially the causation of cancer. Several epidemiological studies have resulted with respect to the total rate of solid cancers that women are more sensitive than men by a factor of 1.6 to 2.0. For leukaemia this is not the case. The largest studies come from the investigations on the survivors of the atomic bombs in Hiroshima and Nagasaki. But also studies on the population of the Techa River (Southeast Urals) yield such data. The analyses of single cancer localizations come to different results with respect to the dependence on the sex. Secondary cancers after radiotherapy for cancer treatment show also higher rates in women than in men. A similar situation is observed with respect to the dependence of cancer rate on age. The total rate of solid cancers is highest with children and decreases with increasing age. The effects are very different again with single cancer localizations. An especially strong age dependence was observed for thyroid cancer. Increasingly individuals have been found who are especially radiosensitive on the basis of their genetic disposition also with respect to the causation of cancer. Mechanisms and possibilities to trace these individuals are discussed. It is also discussed whether and to which extent these data should have consequences for the practical radiological protection. (orig.)

  4. Influence of sensitizing additives on deformation-strength properties of radiation vulcanized rubber

    International Nuclear Information System (INIS)

    Full text: Expanding the practical use of products of radiation-vulcanized elastopolymers (RVEP) makes it necessary to increase their operational properties. Applied to the exploitation of polymers in the field of the ionizing radiation does not always meet shown requirements to them. In the present report the influence of sensitizer of disulpho chloride aromatic compounds on deformation-strength and their ageing under the influence of radiation exposure is being examined. The serial produced aromatic compounds of disulpho chloride bezene (DSCB) were used as sensitizers. It is established that, during the sensitization of radiation chemical vulcanization the mixture of butadiene-nitrile rubber with PVC with other ingredients affect the density of the spatial grid which determines the mechanical properties of vulcanized rubber. Two processes simultaneously run in the presence of sensitizing additives: inhibition of radiation oxidation which causes cross-linking and formation of the spatial grid in BNC. The role of sensitizer in the process of radiation vulcanization is defined first of all by reducing the doze of irradiation in the vulcanization process; simultaneously accelerate the cross-linking of the polymer chains. On the base of physical mechanical and structure of DSCB, can be judged that the influence of ionizing radiation leads the polar groups to ionization besides, their excited potential during ionization is very high which provides material with radiation resistance. Considering the resistance of DSCB to radiation, its practical value is high and can conduct vulcanization at low doses (150-300 kGy). (authors)

  5. Appraisal of radio-protective potential of Tinospora cordifolia against radiation mediated biochemical alterations in intestine

    International Nuclear Information System (INIS)

    per oxidation level through out the period of study which suggests that it has a role in protection against radiation-induced membrane and cellular damage. Thus, the results from the present study demonstrate a radioprotective effect of the T.cordifolia root extract from radiation-induced biochemical alterations in intestine of mammals. (author)

  6. Modulation of radiation induced alteration in the antioxidant status of mice by naringin

    International Nuclear Information System (INIS)

    The alteration of antioxidant status and lipid peroxidation by naringin, a citrus flavoglycoside, was investigated in Swiss albino mice treated with 2 mg/kg b. wt. naringin before exposure to 0.5, 1, 2, 3, and 4 Gy gamma radiation. Lipid peroxidation, glutathione, glutathione peroxidase, catalase and superoxide dismutase were determined in the liver and small intestine of mice treated or not with naringin at 0.5, 1, 2, 4 and 8 h post-irradiation. Whole-body irradiation of mice caused a dose dependent elevation in the lipid peroxidation while a dose dependent depletion was observed for glutathione, glutathione peroxidase, superoxide dismutase and catalase in both liver as well as small intestine. The study demonstrates that naringin protects mouse liver and intestine against the radiation-induced damage by elevating the antioxidant status and reducing the lipid peroxidation

  7. How sensitive is Hawking radiation to superluminal dispersion relations?

    International Nuclear Information System (INIS)

    We discuss the Hawking radiation process in a collapse scenario with superluminal dispersion relations. Due to these superluminal modifications, the horizon effectively becomes frequency-dependent. At every moment of the collapse, a critical frequency can be calculated such that frequencies higher than this critical frequency do not couple to the collapsing geometry and hence do not see any horizon. We discuss three important consequences. First, the late-time radiation in general has a lower intensity than in the standard Hawking picture. Second, the thermal output spectrum depends on the surface gravity, thereby effectively exploring the physics inside the black hole. Third, the radiation dies off as time advances.

  8. Leukocyte activity is altered in a ground based murine model of microgravity and proton radiation exposure.

    Directory of Open Access Journals (Sweden)

    Jenine K Sanzari

    Full Text Available Immune system adaptation during spaceflight is a concern in space medicine. Decreased circulating leukocytes observed during and after space flight infer suppressed immune responses and susceptibility to infection. The microgravity aspect of the space environment has been simulated on Earth to study adverse biological effects in astronauts. In this report, the hindlimb unloading (HU model was employed to investigate the combined effects of solar particle event-like proton radiation and simulated microgravity on immune cell parameters including lymphocyte subtype populations and activity. Lymphocytes are a type of white blood cell critical for adaptive immune responses and T lymphocytes are regulators of cell-mediated immunity, controlling the entire immune response. Mice were suspended prior to and after proton radiation exposure (2 Gy dose and total leukocyte numbers and splenic lymphocyte functionality were evaluated on days 4 or 21 after combined HU and radiation exposure. Total white blood cell (WBC, lymphocyte, neutrophil, and monocyte counts are reduced by approximately 65%, 70%, 55%, and 70%, respectively, compared to the non-treated control group at 4 days after combined exposure. Splenic lymphocyte subpopulations are altered at both time points investigated. At 21 days post-exposure to combined HU and proton radiation, T cell activation and proliferation were assessed in isolated lymphocytes. Cell surface expression of the Early Activation Marker, CD69, is decreased by 30% in the combined treatment group, compared to the non-treated control group and cell proliferation was suppressed by approximately 50%, compared to the non-treated control group. These findings reveal that the combined stressors (HU and proton radiation exposure result in decreased leukocyte numbers and function, which could contribute to immune system dysfunction in crew members. This investigation is one of the first to report on combined proton radiation and

  9. The sensitizing effect of acrylates on radiation vulcanization of natural rubber latex

    International Nuclear Information System (INIS)

    The sensitizing effect of acrylates on radiation vulcanization of natural rubber latex was studied. The results indicate that Gc value of crosslinking (Gc) will be higher at the same radiation dose when a sensitizer exists, and Gc value decreases with the increase of radiation dose (D) conforming to the formula Gc KD-α, where K and α are constants depending on sensitizers. The more sensitizers added, the greater the Gc value. However, the viscosity of the natural rubber latex also increases rapidly along with the increase of sensitizers added. Some sensitizers, such as TMPTA, can decrease the optimum dose from about 200 kGy to approximately 20 kGy according to our experiment. The tensile strength of the film can reach round 20 MPa. Other physical properties are comparable to those of unsensitized. (author)

  10. Differential sensitivity of Chironomus and human hemoglobin to gamma radiation.

    Science.gov (United States)

    Gaikwad, Pallavi S; Panicker, Lata; Mohole, Madhura; Sawant, Sangeeta; Mukhopadhyaya, Rita; Nath, Bimalendu B

    2016-08-01

    Chironomus ramosus is known to tolerate high doses of gamma radiation exposure. Larvae of this insect possess more than 95% of hemoglobin (Hb) in its circulatory hemolymph. This is a comparative study to see effect of gamma radiation on Hb of Chironomus and humans, two evolutionarily diverse organisms one having extracellular and the other intracellular Hb respectively. Stability and integrity of Chironomus and human Hb to gamma radiation was compared using biophysical techniques like Dynamic Light Scattering (DLS), UV-visible spectroscopy, fluorescence spectrometry and CD spectroscopy after exposure of whole larvae, larval hemolymph, human peripheral blood, purified Chironomus and human Hb. Sequence- and structure-based bioinformatics methods were used to analyze the sequence and structural similarities or differences in the heme pockets of respective Hbs. Resistivity of Chironomus Hb to gamma radiation is remarkably higher than human Hb. Human Hb exhibited loss of heme iron at a relatively low dose of gamma radiation exposure as compared to Chironomus Hb. Unlike human Hb, the heme pocket of Chironomus Hb is rich in aromatic amino acids. Higher hydophobicity around heme pocket confers stability of Chironomus Hb compared to human Hb. Previously reported gamma radiation tolerance of Chironomus can be largely attributed to its evolutionarily ancient form of extracellular Hb as evident from the present study. PMID:27237970

  11. Efficacy of Carnosine in Modulating Radiation-Induced Oxidative Damage and Neurotransmitter Alterations in Rat Brain

    International Nuclear Information System (INIS)

    The present study was designed to investigate the role of carnosine (β-alanyl-L-histidine) in alleviating oxidative damage and alteration of neurotransmitters in the brain of rats exposed to gamma radiation. Male albino rats were whole body exposed to a single dose of γ- rays (5 Gy). Carnosine (50 mg/Kg/day) was administered via gavages as follows: a) during 28 successive days, b) during 14 successive days before whole body gamma irradiation and administered distilled water for 14 days after irradiation, c) during 14 successive days before whole body gamma irradiation and during 14 days after irradiation with carnosine. The animals were sacrificed at 1, 7 and 14 days post irradiation. (3 hours after the last dose of carnosine). The results revealed that exposure to γ- rays, (5 Gy(, resulted in significant increases of the levels of thiobarbituric acid reactive substances (TBARS), protein carbonyls (CO), and advanced oxidation protein products (AOPP), associated with significant decreases of superoxide dismutase (SOD) and catalase (CAT) activities, and glutathione (GSH) content which indicate oxidative stress. Gamma rays also, induced significant decrease of the serotonin (5-HT), dopamine (DA), norepinephrine (NE) and epinephrine (EPI) contents as well as significant increase of 5-hydroxy-indole-acetic-acid (5-HIAA) level and monoamine oxidase (MAO) activity which indicated alterations in the metabolism of monoamines. Carnosine has significantly attenuated oxidative stress, and monoamine alterations in the cerebral hemispheres of irradiated rats. Carnosine might preserve the integrity of brain functions.

  12. Sensitivity of Hawking radiation to superluminal dispersion relations

    International Nuclear Information System (INIS)

    We analyze the Hawking radiation process due to collapsing configurations in the presence of superluminal modifications of the dispersion relation. With such superluminal dispersion relations, the horizon effectively becomes a frequency-dependent concept. In particular, at every moment of the collapse, there is a critical frequency above which no horizon is experienced. We show that, as a consequence, the late-time radiation suffers strong modifications, both quantitative and qualitative, compared to the standard Hawking picture. Concretely, we show that the radiation spectrum becomes dependent on the measuring time, on the surface gravities associated with different frequencies, and on the critical frequency. Even if the critical frequency is well above the Planck scale, important modifications still show up.

  13. Process for curing ionizing radiation-highly sensitive resin composition

    International Nuclear Information System (INIS)

    A process is described for curing a radiation curable composition consisting essentially of (a) an amide represented by the formula R,CONR2R3 and (b) an unsaturated polyester resin by irradiating the composition with an ionizing radiation. R1 is H, an alkyl groups having from 1 to 17 carbon atoms or an alkenyl groups having from 1 to 17 carbon atoms, and R2 and R3 are each -H, -CH3, or -CH2OH. R1 and R2 taken together represent alkylene having 2 to 5 carbon atoms

  14. Simulated performance of a position sensitive radiation detecting system (COCAE)

    CERN Document Server

    Karafasoulis, K; Seferlis, S; Kaissas, I; Lambropoulos, C; Loukas, D; Poritiriadis, C

    2011-01-01

    Extensive simulations of a portable radiation detecting system have been performed in order to explore important performance parameters. The instrument consists of a stack of ten detecting layers made of pixelated Cadmium Telluride (CdTe) crystals. Its aim is to localize and identify radiation sources, by exploiting the Compton imaging technique. In this paper we present performance parameters based on simulation studies. Specifically the ratio of incompletely absorbed photons, the detector's absolute efficiency as well as its energy and angular resolution are evaluated in a wide range of incident photon energies.

  15. Sensitivity of aerosol direct radiative forcing to aerosol vertical profile

    OpenAIRE

    Chung, Chul E.; Choi, Jung-Ok

    2014-01-01

    Aerosol vertical profile significantly affects the aerosol direct radiative forcing at the TOA level. The degree to which the aerosol profile impacts the aerosol forcing depends on many factors such as presence of cloud, surface albedo and aerosol single scattering albedo (SSA). Using a radiation model, we show that for absorbing aerosols (with an SSA of 0.7–0.8) whether aerosols are located above cloud or below induces at least one order of magnitude larger changes of the aerosol forcing tha...

  16. Ultraviolet Radiation Sensitivity in Cave Bacteria: Evidence of Adaptation to the Subsurface?

    OpenAIRE

    Snider Jessica R.; Goin Caitlin; Miller Robert V.; Boston Penelope J.; Northup Diana E.

    2009-01-01

    We hypothesize that a reduced capacity to withstand or repair cellular damage from ultraviolet radiation may be present in caveadaptedmicroorganisms that never experience such conditions. However, a small number of previous studies have shown that somesubsurface bacteria do not show greater sensitivity to ultraviolet radiation (UVR) than surface bacteria. To estimate UVR sensitivity incave bacteria, bacterial isolates were collected from Carlsbad Cavern, New Mexico, U.S.A., and percent surviv...

  17. Radiation-induced epigenetic alterations after low and high LET irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Aypar, Umut, E-mail: uaypa001@umaryland.edu [Department of Radiation Oncology, Radiation Oncology Research Laboratory, University of Maryland School of Medicine, Baltimore, MD 21201 (United States); Morgan, William F. [Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Baulch, Janet E. [Department of Radiation Oncology, Radiation Oncology Research Laboratory, University of Maryland School of Medicine, Baltimore, MD 21201 (United States)

    2011-02-10

    Epigenetics, including DNA methylation and microRNA (miRNA) expression, could be the missing link in understanding radiation-induced genomic instability (RIGI). This study tests the hypothesis that irradiation induces epigenetic aberrations, which could eventually lead to RIGI, and that the epigenetic aberrations induced by low linear energy transfer (LET) irradiation are different than those induced by high LET irradiations. GM10115 cells were irradiated with low LET X-rays and high LET iron (Fe) ions and evaluated for DNA damage, cell survival and chromosomal instability. The cells were also evaluated for specific locus methylation of nuclear factor-kappa B (NF{kappa}B), tumor suppressor in lung cancer 1 (TSLC1) and cadherin 1 (CDH1) gene promoter regions, long interspersed nuclear element 1 (LINE-1) and Alu repeat element methylation, CpG and non-CpG global methylation and miRNA expression levels. Irradiated cells showed increased micronucleus induction and cell killing immediately following exposure, but were chromosomally stable at delayed times post-irradiation. At this same delayed time, alterations in repeat element and global DNA methylation and miRNA expression were observed. Analyses of DNA methylation predominantly showed hypomethylation, however hypermethylation was also observed. We demonstrate that miRNA expression levels can be altered after X-ray irradiation and that these miRNA are involved in chromatin remodeling and DNA methylation. A higher incidence of epigenetic changes was observed after exposure to X-rays than Fe ions even though Fe ions elicited more chromosomal damage and cell killing. This distinction is apparent at miRNA analyses at which only three miRNA involved in two major pathways were altered after high LET irradiations while six miRNA involved in five major pathways were altered after low LET irradiations. This study also shows that the irradiated cells acquire epigenetic changes suggesting that epigenetic aberrations may arise

  18. Radiation-induced epigenetic alterations after low and high LET irradiations

    International Nuclear Information System (INIS)

    Epigenetics, including DNA methylation and microRNA (miRNA) expression, could be the missing link in understanding radiation-induced genomic instability (RIGI). This study tests the hypothesis that irradiation induces epigenetic aberrations, which could eventually lead to RIGI, and that the epigenetic aberrations induced by low linear energy transfer (LET) irradiation are different than those induced by high LET irradiations. GM10115 cells were irradiated with low LET X-rays and high LET iron (Fe) ions and evaluated for DNA damage, cell survival and chromosomal instability. The cells were also evaluated for specific locus methylation of nuclear factor-kappa B (NFκB), tumor suppressor in lung cancer 1 (TSLC1) and cadherin 1 (CDH1) gene promoter regions, long interspersed nuclear element 1 (LINE-1) and Alu repeat element methylation, CpG and non-CpG global methylation and miRNA expression levels. Irradiated cells showed increased micronucleus induction and cell killing immediately following exposure, but were chromosomally stable at delayed times post-irradiation. At this same delayed time, alterations in repeat element and global DNA methylation and miRNA expression were observed. Analyses of DNA methylation predominantly showed hypomethylation, however hypermethylation was also observed. We demonstrate that miRNA expression levels can be altered after X-ray irradiation and that these miRNA are involved in chromatin remodeling and DNA methylation. A higher incidence of epigenetic changes was observed after exposure to X-rays than Fe ions even though Fe ions elicited more chromosomal damage and cell killing. This distinction is apparent at miRNA analyses at which only three miRNA involved in two major pathways were altered after high LET irradiations while six miRNA involved in five major pathways were altered after low LET irradiations. This study also shows that the irradiated cells acquire epigenetic changes suggesting that epigenetic aberrations may arise in the

  19. Chemical protection and sensitization to ionizing radiation:molecular investigations

    International Nuclear Information System (INIS)

    Chemical radioprotection and radiosensitization are induced by the presence of certain chemical compounds, which reduce or enhance the effect of ionizing radiation on living organisms. Such substances are either naturally present or may be artificially introduced in the living cells. Chemical radioprotectors are interesting for possible application in the health protection of both professionally exposed workers and patients treated by radiation for diagnostic and thereapeutic purposes. Interest in chemical radiosensitization has increased recently because of its potential application in the radiotherapy of tumours. Both radioprotection and radiosensitization occur by means of complicated mechanisms, which at first correspond to very fast reactions. The mechanism of the interaction between such substances and radiation-induced biological radicals has been investigated by means of pulse radiolysis and rapid mixing techniques. Examples of the application of these techniques are given to illustrate how information has been obtained on the molecular basis of radiation chemical modi-fication at the cellular level. In particular some interactions between model systems of biological interest (DNA, DNA components, enzymes, amino acids, etc.) and sulphur-containing radioprotectors (glutathione, cysteine, etc.) and/or electroaffinic radiosensitizers, are described. (H.K.)

  20. Alterations in pulmonary surfactant protein a metabolism and its diagnostic value in onset of radiation pneumonitis

    International Nuclear Information System (INIS)

    Radiation pneumonitis (RP) is a serious disorder caused by radiation therapy, for the detection of which there exists no simple and sensitive clinical examination. In this study, we examined whether the measurement of serum pulmonary surfactant protein A (SP-A) levels could be effective for detecting the onset of RP. Of the 18 patients included in the study, 9 suffered RP complication after radiation therapy. Serum SP-A levels in patients with RP (64.1±6.5 ng/ml) were 1.82 times as high as those of pre-radiation (36.2±4.0 ng/ml). The difference between them was significant (p=0.0003), while the SP-A value in patients without RP after radiation therapy was almost the same as the pre-radiation level. To study the mechanisms of these elevations, we developed a model of whole lung irradiation (20 Gy) in adult rats. Prior to alveolitis, which was a histological change seen at day 28, levels of SP-A in lung tissue homogenates and bronchoalveolar lavage fluid had become elevated by day 21. Serum SP-A levels in the irradiated rats were significantly elevated by day 21, peaking at day 35, and then declined. Hydroxyproline contents in lung tissues were elevated by day 42 and remained so through day 56. Therefore, the increase in serum SP-A level may be reflected by alveolitis but not fibrosis. In conclusion, determination of serum SP-A could be helpful in detecting the onset of RP. (author)

  1. A systemic administration of liposomal curcumin inhibits radiation pneumonitis and sensitizes lung carcinoma to radiation

    Directory of Open Access Journals (Sweden)

    Shi HS

    2012-05-01

    Full Text Available Hua-shan Shi1,* Xiang Gao,1,3,* Dan Li,1,* Qiong-wen Zhang,1 Yong-sheng Wang,2 Yu Zheng,1 Lu-Lu Cai,1 Ren-ming Zhong,2 Ao Rui,1 Zhi-yong Li,1 Hao Zheng,1 Xian-cheng Chen,1 Li-juan Chen,11State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medicine School, Sichuan University, Chengdu, Sichuan, People's Republic of China; 2State Key Laboratory of Biotherapy and Department of Thoracic Oncology, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, People's Republic of China; 3Deparment of Pathophysiology, College of Preclinical and Forensic Medical Sciences, Sichuan University, Chengdu, People's Republic of China*These authors contributed equally to this workAbstract: Radiation pneumonitis (RP is an important dose-limiting toxicity during thoracic radiotherapy. Previous investigations have shown that curcumin is used for the treatment of inflammatory conditions and cancer, suggesting that curcumin may prevent RP and sensitize cancer cells to irradiation. However, the clinical advancement of curcumin is limited by its poor water solubility and low bioavailability after oral administration. Here, a water-soluble liposomal curcumin system was developed to investigate its prevention and sensitizing effects by an intravenous administration manner in mice models. The results showed that liposomal curcumin inhibited nuclear factor-κB pathway and downregulated inflammatory factors including tumor necrosis factor-α, interleukin (IL-6, IL-8, and transforming growth factor-β induced by thoracic irradiation. Furthermore, the combined treatment with liposomal curcumin and radiotherapy increased intratumoral apoptosis and microvessel responses to irradiation in vivo. The significantly enhanced inhibition of tumor growth also was observed in a murine lung carcinoma (LL/2 model. There were no obvious toxicities observed in mice. The current results indicate that liposomal curcumin can effectively

  2. Sensitivity to plant modelling uncertainties in optimal feedback control of sound radiation from a panel

    DEFF Research Database (Denmark)

    Mørkholt, Jakob

    1997-01-01

    Optimal feedback control of broadband sound radiation from a rectangular baffled panel has been investigated through computer simulations. Special emphasis has been put on the sensitivity of the optimal feedback control to uncertainties in the modelling of the system under control.A model of a...... rectangular baffled panel radiating into free field has been constructed. Secondary actuators have been modelled as vibrational inputs acting directly on the panel. A cost function proportional to the averaged radiated sound power and based on knowledge of the modal amplitudes of the panel has been derived in...... terms of a set of radiation filters modelling the radiation dynamics.Linear quadratic feedback control applied to the panel in order to minimise the radiated sound power has then been simulated. The sensitivity of the model based controller to modelling uncertainties when using feedback from actual and...

  3. Sensitivity study of cloud/radiation interaction using a second order turbulence radiative-convective model

    International Nuclear Information System (INIS)

    A high resolution one-dimensional version of a second order turbulence convective/radiative model, developed at the Los Alamos National Laboratory, was used to conduct a sensitivity study of a stratocumulus cloud deck, based on data taken at San Nicolas Island during the intensive field observation marine stratocumulus phase of the First International Satellite Cloud Climatology Program (ISCCP) Regional Experiment (FIRE IFO), conducted during July, 1987. Initial profiles for liquid water potential temperature, and total water mixing ratio were abstracted from the FIRE data. The dependence of the diurnal behavior in liquid water content, cloud top height, and cloud base height were examined for variations in subsidence rate, sea surface temperature, and initial inversion strength. The modelled diurnal variation in the column integrated liquid water agrees quite well with the observed data, for the case of low subsidence. The modelled diurnal behavior for the height of the cloud top and base show qualitative agreement with the FIRE data, although the overall height of the cloud layer is about 200 meters too high

  4. Effect of low sensitizing radiation doses on immune state during mammary gland cancer radiotherapy

    International Nuclear Information System (INIS)

    Results of clinical application of preoperational radiotherapy of mammary gland cancer at low sensitizing radiation doses (0.1 Gr) before using the main single dose (1.9 Gr) for modification of tumor radiosensitivity and increase of efficiency of radiotherapy are presented. Small radiation doses are stated to promote decrease of the number of skin radiation reactions, conservation of blood and T-immunosystem parameters within the limits of physiologic oscillations

  5. Radiation-Sensitive Indicator Based on m-Cresol Purple Dyed Poly (vinyl Butyral) for Possible Use in Radiation Dosimetry

    International Nuclear Information System (INIS)

    In the present work a PVB films containing different concentrations of m-cresol purple (ph indicator) and chloral hydrate were prepared. The chlorine containing (chIoral hydrate) polymer was dehydrochlorinated when the material irradiated thereby reducing ph and causing the acid-sensitive dye to change color. Such materials are not, however, reported to be sensitive. and quantitative at relatively low radiation doses. The useful dose ranges of this film ranges between 2 and 6 kGy. Radiation chemical yield was calculated. The effects of temperature and relative humidity during irradiation as well as pre and post irradiation stability on the response of films were described

  6. Sensitivity of the vibrios to ultraviolet-radiation

    International Nuclear Information System (INIS)

    The ultraviolet-inactivation kinetics of a number of strains of Vibrio cholerae (classical), Vibrio cholerae (el tor), NAG vibrios and Vibrio parahaemolyticus were investigated. Statistical analyses revealed significant differences between any two of the four types of vibrio in respect of their sensitivity to U.V. (author)

  7. Radiation sensitivity of fungal microflora isolated from some pharmaceutical ingredients

    International Nuclear Information System (INIS)

    The total number of fungal microflora of D-glucose, NaCl, KCl and their solutions was determined. The fungal isolates were identified as Aspergillus fumigatus. Aspergillus niger; Spicaria divaricate and Spicaria silvatica and their response to γ-radiation was determined, the most predominant isolate Asp. fumigatus was also the most irradiation resistant. The Dio and the lethal dose were determined for each isolate in a pure spore suspension as well as in the presence of the other isolates. The higher lethal dose values obtained for pure spore suspension as compared to that obtained for the natural fungal flora a D-glucose are discussed in terms of spore clumping. The activity of amylase, protease and L-asparaginase of Asp. fumigatus was examined prior to and after exposure to different doses of γ-radiation. Though all were inhibited at high doses, the effect was not as drastic as it was on cell viability

  8. Sensitivity to Alternaria alternata toxin in citrus because of altered mitochondrial RNA processing

    OpenAIRE

    Ohtani, Kouhei; Yamamoto, Hiroyuki; Akimitsu, Kazuya

    2002-01-01

    Specificity in the interaction between rough lemon (Citrus jambhiri Lush.) and the fungal pathogen Alternaria alternata rough lemon pathotype is determined by a host-selective toxin, ACR-toxin. Mitochondria from rough lemon are sensitive to ACR-toxin whereas mitochondria from resistant plants, including other citrus species, are resistant. We have identified a C. jambhiri mitochondrial DNA sequence, designated ACRS (ACR-toxin sensitivity gene), that confers toxin sensitivity to Escherichia co...

  9. Studies on radiation-sensitive nonsilver halide materials, (2)

    International Nuclear Information System (INIS)

    Dye-precursors made from furfural and some aniline derivatives become red-colored upon irradiation with ionization radiatios in PVC matrix, forming Stenhouse salts with the HCl evolved from the matrix. The coloration of the precursor from N-methylaniline, having the most excellent potential for dosimetry among the precursors, was studied for the irradiation of electron beam (60 kV) and X-ray (50 - 240 kVp). The following conclusions were obtained for the electron beam bombardment. (1) The response range is 10-8 - 10-6 C/cm2 or 103 - 105 rad, where good linearity between coloration and charge density exists. (2) The highest sensitivity is obtained when the concentration of the precursor is >=5 wt% for the amount of PVC and the film thickness is >=32 μm. (3) Addition of 25 wt% of DOP enhances not only the sensitivity by ca. 20% but also the stability of the color from several days to several months. (4) The sensitivity is increased by ca. 15% when a conductive base is used for the film. (5) G value for the formation of the dye, i.e., that for the formation of HCl is 13.5 - 15.5. The followings were obtained for the irradiation of X-ray. (1) The response range is 103 - 105 R or rad. (2) The sensitivity for the absorbed dose is independent of the energy but is approximately proportional to the film thickness. (3) The sensitivity is higher than that for electrons by the factor of ca. 1.6, reflecting the higher G(HCl) value, 23 - 25. (author)

  10. Andrographolide Sensitizes Ras-Transformed Cells to Radiation in vitro and in vivo

    International Nuclear Information System (INIS)

    Purpose: Increasing the sensitivity of tumor cells to radiation is a major goal of radiotherapy. The present study investigated the radiosensitizing effects of andrographolide and examined the molecular mechanisms of andrographolide-mediated radiosensitization. Methods and Materials: An H-ras-transformed rat kidney epithelial (RK3E) cell line was used to measure the radiosensitizing effects of andrographolide in clonogenic assays, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide assays, and a xenograft tumor growth model. The mechanism of andrographolide-sensitized cell death was analyzed using annexin V staining, caspase 3 activity assays, and terminal transferase uridyl nick end labeling assays. The roles of nuclear factor kappa B (NF-κB) and Akt in andrographolide-mediated sensitization were examined using reporter assays, electrophoretic mobility shift assays, and Western blotting. Results: Concurrent andrographolide treatment (10 μM, 3 h) sensitized Ras-transformed cells to radiation in vitro (sensitizer enhancement ratio, 1.73). Andrographolide plus radiation (one dose of 300 mg/kg peritumor andrographolide and one dose of 6 Gy radiation) resulted in significant tumor growth delay (27 ± 2.5 days) compared with radiation alone (22 ± 1.5 days; p <.05). Radiation induced apoptotic markers (e.g., caspase-3, membrane reversion, DNA fragmentation), and andrographolide treatment did not promote radiation-induced apoptosis. However, the protein level of activated Akt was significantly reduced by andrographolide. NF-κB activity was elevated in irradiated Ras-transformed cells, and andrographolide treatment significantly reduced radiation-induced NF-κB activity. Conclusion: Andrographolide sensitized Ras-transformed cells to radiation both in vitro and in vivo. Andrographolide-mediated radiosensitization was associated with downregulation of Akt and NF-κB activity. These observations indicate that andrographolide is a novel radiosensitizing agent

  11. Sensitivity of Escherichia coli acrA Mutants to Psoralen plus Near-Ultraviolet Radiation

    DEFF Research Database (Denmark)

    Hansen, M. Trier

    1982-01-01

    The sensitivity to psoralen plus near-ultraviolet radiation (PUVA) was compared in a pair of E. coli strains differing at the acrA locus. Survival was determined for both bacteria and phage λ. AcrA mutant cells were 40 times more sensitive than wild type to the lethal effect of PUVA. Free λ phage...

  12. Radiation effects in ultraviolet sensitive SiC photodiodes

    International Nuclear Information System (INIS)

    We tested SiC photodiodes with Co-60 gamma rays up to a total dose of 22 Mrad(SiC) and 32 MeV protons up to a fluence of 9 x 1012 cm-2. They showed a decrease in sensitivity of about 50% at a dose of 1 Mrad. The same decrease or somewhat less was observed during proton irradiations when the fluence is converted to an applied dose. (authors)

  13. Gimeracil sensitizes cells to radiation via inhibition of homologous recombination

    International Nuclear Information System (INIS)

    Background and purpose: 5-Chloro-2,4-dihydroxypyridine (Gimeracil) is a component of an oral fluoropyrimidine derivative S-1. Gimeracil is originally added to S-1 to yield prolonged 5-FU concentrations in tumor tissues by inhibiting dihydropyrimidine dehydrogenase, which degrades 5-FU. We found that Gimeracil by itself had the radiosensitizing effect. Methods and materials: We used various cell lines deficient in non-homologous end-joining (NHEJ) or homologous recombination (HR) as well as DLD-1 and HeLa in clonogenic assay. γ-H2AX focus formation and SCneo assay was performed to examine the effects of Gimeracil on DNA double strand break (DSB) repair mechanisms. Results: Results of γ-H2AX focus assay indicated that Gimeracil inhibited DNA DSB repair. It did not sensitize cells deficient in HR but sensitized those deficient in NHEJ. In SCneo assay, Gimeracil reduced the frequency of neo-positive clones. Additionally, it sensitized the cells in S-phase more than in G0/G1. Conclusions: Gimeracil inhibits HR. Because HR plays key roles in the repair of DSBH caused by radiotherapy, Gimeracil may enhance the efficacy of radiotherapy through the suppression of HR-mediated DNA repair pathways.

  14. Silver nanoparticles: a novel radiation sensitizer for glioma?

    Science.gov (United States)

    Liu, Peidang; Huang, Zhihai; Chen, Zhongwen; Xu, Ruizhi; Wu, Hao; Zang, Fengchao; Wang, Cailian; Gu, Ning

    2013-11-01

    Malignant gliomas are the most common primary intracranial tumors with a dismal prognosis. Previous investigations by our group demonstrated the radiosensitizing effect of silver nanoparticles (AgNPs) on glioma cells in vitro. The goal of the present study was to evaluate the efficacy of intratumoral administration of AgNPs in combination with a single dose of ionizing radiation at clinically relevant MV energies for the treatment of C6 glioma-bearing rats. AgNPs (10 or 20 μg/10 μl) were stereotactically administered on day 8 after tumor implantation. One day after AgNP injection, rats bearing glioma received 10 Gy radiation. The mean survival times were 100.5 and 98 days, the corresponding percent increase in life spans was 513.2% and 497.7%, and the cure rates were 41.7 and 38.5% at 200 days for the 10 and 20 μg AgNPs and radiation combination groups, respectively. In contrast, the mean survival times for irradiated controls, 10 and 20 μg AgNPs alone, and untreated controls were 24.5, 16.1, 19.4, and 16.4 days, respectively. Furthermore, a cooperative antiproliferative and proapoptotic effect was obtained when gliomas were treated with AgNPs followed by radiotherapy. Our results showed the therapeutic efficacy of AgNPs in combination with radiotherapy without apparent systemic toxicity, suggesting the clinical potential of AgNPs in improving the outcome of malignant glioma radiotherapy.Malignant gliomas are the most common primary intracranial tumors with a dismal prognosis. Previous investigations by our group demonstrated the radiosensitizing effect of silver nanoparticles (AgNPs) on glioma cells in vitro. The goal of the present study was to evaluate the efficacy of intratumoral administration of AgNPs in combination with a single dose of ionizing radiation at clinically relevant MV energies for the treatment of C6 glioma-bearing rats. AgNPs (10 or 20 μg/10 μl) were stereotactically administered on day 8 after tumor implantation. One day after Ag

  15. Uncertainty and Sensitivity Analysis of Afterbody Radiative Heating Predictions for Earth Entry

    Science.gov (United States)

    West, Thomas K., IV; Johnston, Christopher O.; Hosder, Serhat

    2016-01-01

    The objective of this work was to perform sensitivity analysis and uncertainty quantification for afterbody radiative heating predictions of Stardust capsule during Earth entry at peak afterbody radiation conditions. The radiation environment in the afterbody region poses significant challenges for accurate uncertainty quantification and sensitivity analysis due to the complexity of the flow physics, computational cost, and large number of un-certain variables. In this study, first a sparse collocation non-intrusive polynomial chaos approach along with global non-linear sensitivity analysis was used to identify the most significant uncertain variables and reduce the dimensions of the stochastic problem. Then, a total order stochastic expansion was constructed over only the important parameters for an efficient and accurate estimate of the uncertainty in radiation. Based on previous work, 388 uncertain parameters were considered in the radiation model, which came from the thermodynamics, flow field chemistry, and radiation modeling. The sensitivity analysis showed that only four of these variables contributed significantly to afterbody radiation uncertainty, accounting for almost 95% of the uncertainty. These included the electronic- impact excitation rate for N between level 2 and level 5 and rates of three chemical reactions in uencing N, N(+), O, and O(+) number densities in the flow field.

  16. Radiation and heat sensitivity of microflora in mixed spices

    International Nuclear Information System (INIS)

    Spices such as coriander, cumin, turmeric, chilli collected from local market were found to be highly contaminated with bacteria and fungi. A dose of 3 kGy without heat treatment reduced the microbial load from 6 log to 3 log and from 5 log to 2 log units depending on the storage temperature whereas the same dose of radiation combined with heat treatment reduced the microbial load from 6 log to 2 log units and from 4 log to below detectable level depending on storage condition. The combination treated spices retained good organoleptic quality in comparison to that of only irradiated species with higher dose. 11 refs., 2 tables (author)

  17. Alterations of CNS structure & function by charged particle radiation & resultant oxidative stress

    Science.gov (United States)

    Nelson, Gregory; Chang, Polly; Favre, Cecile; Fike, John; Komarova, Natalia; Limoli, Charles; Mao, Xiao-Wen; Obenaus, Andre; Raber, Jacob; Spigelman, Igor; Soltesz, Ivan; Song, Sheng-Kwei; Stampanoni, Marco; Vlkolinsky, Roman; Wodarz, Dominik

    The NSCOR program project is transitioning from establishing the existence of CNS responses to low doses of charged particles, to an investigation of mechanisms underlying these changes and extending the irradiation paradigm to more space-like exposures. In earlier experiments we examined radiation responses of the mouse brain (hippocampus) following exposure to 250 MeV protons and 600 MeV/n iron ions. Our key findings on structural changes were: 1) Significant dose and time dependent loss of en-dothelial cells and microvessel network remodeling occurs suggesting that vascular insufficiency is produced. 2) Significant dose dependent losses of neural precursor cells were observed in a lineage specific pattern which may be associated with cognitive impairment. 3) Evaluation of DNA damage showed dose and time dependent accumulation of mutations with region-specific mutation structures and gene expression profiling demonstrated activation of neurotrophic and adhesion factors as well as chemokine receptors associated with inflammation. Our key find-ings on functional changes were: 1) Time and dose dependent modifications to neural output expressed as enhanced excitability but reduced synaptic efficacy and plasticity (including long term potentiation). 2) Intrinsic membrane properties of neurons were not significantly modi-fied by radiation exposure but pharmacological treatments demonstrated changes in inhibitory synapses. 3) MRI imaging visualized brain structural changes based on altered water diffu-sion properties and patterns were consistent with demyelination or gliosis. Our key findings on neurodegeneration and fidelity of homeostasis were: 1) APP23 transgenic mice exhibited accelerated APP-type electrophysiological pathology over several months. 2) Microvessel net-work changes following irradiation were suggestive of poor tissue oxygenation. 3) The ability of the brain to respond a controlled septic shock was altered by irradiation; the septic shock reactions

  18. Solar Radiation Alters Toxicity of Carbofuran: Evidence from Empirical Trials with Duttaphyrnus melanostictus

    Directory of Open Access Journals (Sweden)

    M.R. Wijesinghe

    2011-10-01

    Full Text Available In the present study we investigated the potential of natural solar radiation to alter the toxicity of a commonly used carbamate pesticide, carbofuran, on tadpoles of the Common Asian Toad Duttaphrynus melanostictus. A single exposure trial was conducted over 96 hrs with three concentrations (150, 250 and 500 µgl-1 of photo-irradiated and non-irradiated carbofuran. Results show that photo-irradiation markedly reduced the toxicity of carbofuran as evident by its effects on three end points, i.e. mortality, growth and swimming activity. The mortality of tadpoles exposed to irradiated carbofuran was significantly lower than those exposed to the non-irradiated pesticide. Both treatment and control tadpoles showed a hormetic response for mortality. Tadpoles in irradiated tanks were also larger and more active than those in the control tanks. Photo-altered toxicity was evident at all three tested concentrations. The results of this study therefore signals caution when directly linking  results of empirical trials to field scenarios and highlight the necessity to evaluate toxic effects of compounds under variable environmental conditions.Keywords: Carbofuran, Duttaphrynus melanostictus, photo-degradation, tadpoles, toxicity

  19. Solar Radiation Alters Toxicity of Carbofuran: Evidence from Empirical Trials with Duttaphyrnus melanostictus

    Directory of Open Access Journals (Sweden)

    M.R.Wijesinghe

    2011-10-01

    Full Text Available In the present study we investigated the potential of natural solar radiation to alter the toxicity of a commonly used carbamate pesticide, carbofuran, on tadpoles of the Common Asian Toad Duttaphrynus melanostictus. A single exposure trial was conducted over 96 hrs with three concentrations (150, 250 and 500 µgl-1 of photo-irradiated and non-irradiated carbofuran. Results show that photo-irradiation markedly reduced the toxicity of carbofuran as evident by its effects on three end points, i.e. mortality, growth and swimming activity. The mortality of tadpoles exposed to irradiated carbofuran was significantly lower than those exposed to the non-irradiated pesticide. Both treatment and control tadpoles showed a hormetic response for mortality. Tadpoles in irradiated tanks were also larger and more active than those in the control tanks. Photo-altered toxicity was evident at all three tested concentrations. The results of this study therefore signals caution when directly linking results of empirical trials to field scenarios and highlight the necessity to evaluate toxic effects of compounds under variable environmental conditions.

  20. Synchrotron radiation X-ray fluorescence analysis on altered mineral muscovite in gold deposit

    Institute of Scientific and Technical Information of China (English)

    TANG Yun-Hui; YUAN Wan-Ming; WANG Li-Hua; HAN Chun-Ming; HUANG Yu-Ying; HE Wei

    2005-01-01

    Synchrotron radiation X-ray fluorescence (SRXRF) microprobe was used to ananlyse altered mineral muscovite and its surrounding feldspar in Yuerya gold deposit. The major, minor and trace elements of the two minerals were detected and analyzed. SRXRF analysis showed that the Yuerya muscovite had a complex chemical composition, containing K, Fe, Ca, Ti, Cr, Mn, Co, Cu, Zn and many trace or ultra-trace elements. Since muscovite resulted from the alteration of hydrothermal ore fluid acting on feldspar (plagioclase), the difference of chemical composition between the two minerals shows the components of ore fluid, which are characterized by the enrichment of alkaline and alkaline-earth metal elements K, Ca and ore-associated elements Fe, Cu, Zn. And gold, silver and platinum, invisible under microscope, were detected in some areas of muscovite, but not found in feldspar. Especially platinum, a mantle material, is rarely seen in the earth crust but now found in the gold deposit of magmatic sources; its appearance approves the idea of mantle flux participating in the gold mineralization, which suggests that the tectonic event controlling gold mineralization in the Yuerya district is a mantle phenomenon.

  1. Sensitization of Salmonella typhi towards gamma-radiation by ascorbic acid

    International Nuclear Information System (INIS)

    The sensitivity of a S. typhi culture to γ-radiation has been examined. The D10 value, when the culture was irradiated in phosphate buffer, was found to be 70 krad. The addition of ascorbic acid (at a concentration of 0.57 mM) during irradiation, sensitized this organism quite markedly towards γ-radiation. This was evident from the observation that the D10 value was reduced to 20 krad when cells were irradiated in the ascorbic acid. Ascorbic acid was converted to its oxidized form during the radiation process. Irradiation under nitrogen instead of air inhibited the sensitization afforded by ascorbic acid. The population of cells surviving after irradiation in the presence of ascorbic acid showed a higher activity of catalase than its buffer-irradiated counterpart. The implication of the role of hydrogen peroxide (one of the possible intermediates formed during the oxidation of ascorbic acid) in sensitization is discussed. (author)

  2. Intrinsic radiation sensitivity is conserved during immortalization and malignant transformation steps in carcinogenesis

    International Nuclear Information System (INIS)

    The authors examined the effect of malignant transformation on the intrinsic radiation sensitivity of epithelial cells. Normal human epidermal keratinocytes (HEK), keratinocytes immortalized by hybrid virus (Ad12-SV-40) and malignant keratinocytes transformed by chemical carcinogens or the Ki-MSV were tested with graded doses of ionizing radiation. Normal HEK cells (D/sub 0/ = 2.24 Gy) proved to be more resistant to radiation than normal human fibroblasts (D/sub 0/=1.45 Gy). Mean inactivation doses D bar ranged from 3.47 to 4.27 Gy confirming a radiation resistant phenotype. This resistance was conserved in immortalized HEK cells and in malignant HEK cells. These experiments suggest that radiation sensitivity is an intrinsic property inherited from the parent cell that may be independent of the steps associated with carcinogenesis

  3. Sensitiveness to cosmic radiation: on some aspects of data collection and their representation

    International Nuclear Information System (INIS)

    During simulation of cosmic radiation effects, the energy deposition by length unit is altered because of energy lowering along the range. This mechanism is illustrated by exhaustive data got from the microprocessor type 2901. Wrong conclusions may be deduced concerning behavior in space field. New representations of cross sections are presented; they lead to safer predictions on behavior in space environment

  4. Proteomic Alterations in B Lymphocytes of Sensitized Mice in a Model of Chemical-Induced Asthma

    OpenAIRE

    Steven Haenen; Jeroen A.J. Vanoirbeek; Vanessa De Vooght; Liliane Schoofs; Benoit Nemery; Elke Clynen; Hoet, Peter H. M.

    2015-01-01

    Introduction and Aim The role of B-lymphocytes in chemical-induced asthma is largely unknown. Recent work demonstrated that transferring B lymphocytes from toluene diisocyanate (TDI)-sensitized mice into naïve mice, B cell KO mice and SCID mice, triggered an asthma-like response in these mice after a subsequent TDI-challenge. We applied two-dimensional difference gel electrophoresis (2D-DIGE) to describe the “sensitized signature” of B lymphocytes comparing TDI-sensitized mice with control mi...

  5. Sensitive Detection of Cold Cesium Molecules by Radiative Feshbach Spectroscopy

    OpenAIRE

    Chin, Cheng; Kerman, Andrew J.; Vuletić, Vladan; Chu, Steven

    2002-01-01

    We observe the dynamic formation of $Cs_2$ molecules near Feshbach resonances in a cold sample of atomic cesium using an external probe beam. This method is 300 times more sensitive than previous atomic collision rate methods, and allows us to detect more than 20 weakly-coupled molecular states, with collisional formation cross sections as small as $\\sigma =3\\times 10^{-16}$cm$^2$. We propose a model to describe the atom-molecule coupling, and estimate that more than $2 \\times 10^5$ $Cs_2$ mo...

  6. Hydroxyurea as a radiation sensitizer in malignancies of the head and neck

    International Nuclear Information System (INIS)

    A prospective randomized trail was undertaken to assess the efficacy of hydroxyurea as a radiation sensitizer. Disease control rates achieved significance (p<0.01) values only at 2 and 3 months post-radiation. At the end of 2 years of follow-up there was no significant difference in the disease control rate between the control and the experimental group. The toxicity in the experimental group was acceptable. One patient had severe vomiting; 13% showed severe mucositis, 4.5% had erythema of the treatment area and 40% showed dry desquamation. There seems to be no added advantage of hydroxyurea and radiation over radiation alone. (author). 12 refs., 2 tabs

  7. Singlet Oxygen-Mediated Oxidation during UVA Radiation Alters the Dynamic of Genomic DNA Replication.

    Directory of Open Access Journals (Sweden)

    Dany Graindorge

    Full Text Available UVA radiation (320-400 nm is a major environmental agent that can exert its deleterious action on living organisms through absorption of the UVA photons by endogenous or exogenous photosensitizers. This leads to the production of reactive oxygen species (ROS, such as singlet oxygen (1O2 and hydrogen peroxide (H2O2, which in turn can modify reversibly or irreversibly biomolecules, such as lipids, proteins and nucleic acids. We have previously reported that UVA-induced ROS strongly inhibit DNA replication in a dose-dependent manner, but independently of the cell cycle checkpoints activation. Here, we report that the production of 1O2 by UVA radiation leads to a transient inhibition of replication fork velocity, a transient decrease in the dNTP pool, a quickly reversible GSH-dependent oxidation of the RRM1 subunit of ribonucleotide reductase and sustained inhibition of origin firing. The time of recovery post irradiation for each of these events can last from few minutes (reduction of oxidized RRM1 to several hours (replication fork velocity and origin firing. The quenching of 1O2 by sodium azide prevents the delay of DNA replication, the decrease in the dNTP pool and the oxidation of RRM1, while inhibition of Chk1 does not prevent the inhibition of origin firing. Although the molecular mechanism remains elusive, our data demonstrate that the dynamic of replication is altered by UVA photosensitization of vitamins via the production of singlet oxygen.

  8. Alterations in transcription factor binding in radioresistant human melanoma cells after ionizing radiation

    International Nuclear Information System (INIS)

    We analyzed alterations in transcription factor binding to specific, known promoter DNA consensus sequences between irradiated and unirradiated radioresistant human melanoma (U1-Mel) cells. The goal of this study was to begin to investigate which transcription factors and DNA-binding sites are responsible for the induction of specific transcripts and proteins after ionizing radiation. Transcription factor binding was observed using DNA band-shift assays and oligonucleotide competition analyses. Confluence-arrested U1-Mel cells were irradiated (4.5 Gy) and harvested at 4 h. Double-stranded oligonucleotides containing known DNA-binding consensus sites for specific transcription factors were used. Increased DNA binding activity after ionizing radiation was noted with oligonucleotides containing the CREB, NF-kB and Sp1 consensus sites. No changes in protein binding to AP-1, AP-2, AP-3, or CTF/NF1, GRE or Oct-1 consensus sequences were noted. X-ray activation of select transcription factors, which bind certain consensus sites in promoters, may cause specific induction or repression of gene transcription. 22 refs., 2 figs

  9. Evaluation of the morphological alteration of the root surface radiated with a diode laser

    International Nuclear Information System (INIS)

    The diode laser has been studied for periodontal therapy, as much for removal of calculus as for microbial reduction of periodontal pockets, as well as the visible analgesic effects and biomodulation capacity. For this reason the purpose of this study was to evaluate the morphological alteration of the root surface after radiation with the diode laser, 808 nm through analysis by scanning electron microscopy (SEM). Besides this, to verify the temperature variations caused during the radiation, a thermometer put into the dentinal wall of the root canal was used. In all, 18 teeth were used, 15 of which for the SEM study, and the other 3 were used to temperature variation analysis. The 25 samples were scraped on the root surface and planed with manual instruments. The other 5 were not subjected to any type of treatment. This, 6 groups of 5 samples each were formed. Control Group C whose samples had not received any treatment; Control Group C 1 was only scraped and polished conventionally with Hu-Friedy Gracey curettes 5 and 6; the other samples groups L1, L2, L3, L4 were radiated by diode laser using parameters of power 1,0 W; 1,2 W; 1,4 W; and 1,6 W respectively, 2 times for 10 seconds with 20 seconds intervals between each radiation in continuous mode. The results with relation to the increase of temperature in the interior of the root canal demonstrated that there was an increase of more than 5 degree Celsius. The results of the scanning electron microscope analysis of Control Group C demonstrated great irregularity and ridges on the root surface, with the presence of a dentine layer. Control Group C1 presented a similar aspect to Group L 1's, smoother and more homogeneous surface. Groups L2, L3, and L4 presented scratches alternating with smoother areas showing that fiber contacted the surface of the sample. The results reconfirmed the necessity of further studies using diode laser, with a beam of light emitted in an interrupted mode to improve the control of the

  10. Oyster radiation sensitivity; Sensibilidade de ostras a radiacao

    Energy Technology Data Exchange (ETDEWEB)

    Marchese, Sandra R.M. [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), SP (Brazil); Mastro, Nelida L. del [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    1996-07-01

    Various food products like oysters, crabs and shrimps have been described as possible Vibrio spp. transmitting agents. Seafood irradiation is been presented as an alternative among the different public health intervention measures to control food borne diseases. The objective of this work was to establish, firstly, the radioresistance of Crassostrea brasiliana oysters. The oysters were irradiated with Co-60 radiation with doses of 0, 1.5,3 and 6 kGy. Survival curves a function of time showed that 100% of samples irradiated with 3 kGy survived at least 6 days; among those irradiated with 6 kGy, 100% survived 3 days. These results are encouraging since a dose of 2 kGy is already effective in diminishing oyster bioburden. (author)

  11. Protracted Oxidative Alterations in the Mechanism of Hematopoietic Acute Radiation Syndrome

    Directory of Open Access Journals (Sweden)

    Nikolai V. Gorbunov

    2015-02-01

    Full Text Available The biological effects of high-dose total body ionizing irradiation [(thereafter, irradiation (IR] are attributed to primary oxidative breakage of biomolecule targets, mitotic, apoptotic and necrotic cell death in the dose-limiting tissues, clastogenic and epigenetic effects, and cascades of functional and reactive responses leading to radiation sickness defined as the acute radiation syndrome (ARS. The range of remaining and protracted injuries at any given radiation dose as well as the dynamics of post-IR alterations is tissue-specific. Therefore, functional integrity of the homeostatic tissue barriers may decline gradually within weeks in the post-IR period culminating with sepsis and failure of organs and systems. Multiple organ failure (MOF leading to moribundity is a common sequela of the hemotapoietic form of ARS (hARS. Onset of MOF in hARS can be presented as “two-hit phenomenon” where the “first hit” is the underlying consequences of the IR-induced radiolysis in cells and biofluids, non-septic inflammation, metabolic up-regulation of pro-oxidative metabolic reactions, suppression of the radiosensitive hematopoietic and lymphoid tissues and the damage to gut mucosa and vascular endothelium. While the “second hit” derives from bacterial translocation and spread of the bacterial pathogens and inflammagens through the vascular system leading to septic inflammatory, metabolic responses and a cascade of redox pro-oxidative and adaptive reactions. This sequence of events can create a ground for development of prolonged metabolic, inflammatory, oxidative, nitrative, and carbonyl, electrophilic stress in crucial tissues and thus exacerbate the hARS outcomes. With this perspective, the redox mechanisms, which can mediate the IR-induced protracted oxidative post-translational modification of proteins, oxidation of lipids and carbohydrates and their countermeasures in hARS are subjects of the current review. Potential role of ubiquitous

  12. Effects of peroxide and catalase on near ultraviolet radiation sensitivity in Escherichia coli strains

    International Nuclear Information System (INIS)

    The role of peroxide and catalase on NUV radiation sensitivity was examined in two repair competent E. coli strains, AB1157 and B/r. Exponential phase B/r is considerably more sensitive to NUV radiation than exponential phase AB1157. However, resistance to 5 mmol dm-3 H2O2 was induced in both AB1157 and B/r by pretreating growing cells with 30 μmol dm-3 H2O2. Pretreatment also induced resistance to broad-band NUV radiation in these strains. The addition of catalase to the post-irradiation plating medium increased survival to the same extent as that provided by pretreatment with 30 μmol dm-3 H2O2, in both strains. The NUV radiation sensitivity seen in B/r does not appear to be due to a deficiency in enzymes that scavenge H2O2, as a catalase deficient mutant, E. coli UM1, is more resistant to NUV radiation than B/r. Also, assays for H2O2 scavenging ability show little difference between AB1157 and B/r in this respect. Two hypotheses are put forward to account for the sensitivity of exponential phase B/r. Whilst it is apparent that peroxides and catalase do have a role in NUV radiation damage, it is clear that other factors also influence survival under certain conditions. (author)

  13. Adiponectin in mice with altered growth hormone action: links to insulin sensitivity and longevity?

    OpenAIRE

    Lubbers, Ellen R; List, Edward O.; Jara, Adam; Sackman-Sala, Lucila; Cordoba-Chacon, Jose; Gahete, Manuel D.; Kineman, Rhonda D.; Boparai, Ravneet; Bartke, Andrzej; Kopchick, John J.; Berryman, Darlene E.

    2013-01-01

    Adiponectin is positively correlated with longevity and negatively correlated with many obesity-related diseases. While there are several circulating forms of adiponectin, the high molecular weight (HMW) version has been suggested to have the predominant bioactivity. Adiponectin gene expression and cognate serum protein levels are of particular interest in mice with altered growth hormone (GH) signaling as these mice exhibit extremes in obesity that are positively associated with insulin sens...

  14. Development of passive radiation detectors of improved sensitivity

    Science.gov (United States)

    Chakrabarty, M. R.

    1986-01-01

    The future development of a solid track high energy particle detector is discussed. The goal is to improve the sensitivity and lower the threshold of the detector. One most widely used material for such purpose is a plastic commercially known as CR-39. A scheme is presented which involves changing the formula of the monomer, diethylene glycol-bis-allyl carbonate. This is to be accomplished by substituting some heteroatoms for H and substituting sulfur atoms for oxygen in the ether linkages. Use of a new plasticizer to make the etched surface clearer than what has been accomplished as of today is suggested. Possible improvement in acquiring better tracks and increasing the ratio of V sub T/V sub B was planned. This is to be accomplished by changing the composition of the etchants, etching time, and etching temperature.

  15. Genetic and molecular characterization of radiation-sensitive mutants of the slime mold, Dictyostelium discoideum

    International Nuclear Information System (INIS)

    Several radiation-sensitive mutants of Dictyostelium discoideum, isolated on the basis of sensitivity to either 60Co gamma rays or 254 nm ultraviolet light (uv), were genetically characterized. The mutations studied can be classified into three types on the basis of their radiation-sensitive phenotype. Type one mutants are very sensitive compared to their parental radiation-resistant strains to both uv and gamma rays with no shoulder on their survival curves. Type two mutants have a sensitivity to both uv and gamma rays intermediate between that of the type one mutants and that of their parental strains; type two mutants have shoulders on both uv and gamma ray survival curves. Type three mutant are sensitive only to uv and are as resistant as their parental strains to gamma rays. The type three mutants have intermediate sensitivities to uv like the type two mutants and have shoulders on their survival curves. Linkage and complementation studies indicate that the ten radiation-sensitive mutations studied identify at least six but probably eight loci involved with DNA repair in D. discoideum. Alkaline sucrose gradient sedimentation profiles of DNA from cells following uv irradiation (15 J/m2) indicate that all type one and type two uv- and gamma-ray-sensitive mutants studied can make and repair single strand breaks. However the type three mutants (radC strains) made few single strand breaks under identical conditions, suggesting that these mutants are defective in excision repair. The evidence obtained indicates that D. discoideum has at least two pathways involved with the repair of uv-induced DNA damage

  16. Highly sensitivity adhesion molecules detection in hereditary haemochromatosis patients reveals altered expression.

    LENUS (Irish Health Repository)

    Norris, S

    2012-02-01

    Several abnormalities in the immune status of patients with hereditary haemochromatosis (HH) have been reported, suggesting an imbalance in their immune function. This may include persistent production of, or exposure to, altered immune signalling contributing to the pathogenesis of this disorder. Adhesion molecules L-, E- and P-Selectin, intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) are some of the major regulators of the immune processes and altered levels of these proteins have been found in pathological states including cardiovascular diseases, arthritis and liver cancer. The aim of this study was to assess L-, E- and P-Selectin, ICAM-1 and VCAM-1 expression in patients with HH and correlate these results with HFE mutation status and iron indexes. A total of 139 subjects were diagnosed with HH (C282Y homozygotes = 87, C282Y\\/H63D = 26 heterozygotes, H63D homozygotes = 26), 27 healthy control subjects with no HFE mutation (N\\/N), 18 normal subjects heterozygous for the H63D mutation served as age-sex-matched controls. We observed a significant decrease in L-selectin (P = 0.0002) and increased E-selectin and ICAM-1 (P = 0.0006 and P = 0.0059) expression in HH patients compared with healthy controls. This study observes for the first time that an altered adhesion molecules profile occurs in patients with HH that is associated with specific HFE genetic component for iron overload, suggesting that differential expression of adhesion molecules may play a role in the pathogenesis of HH.

  17. A chilling sensitive mutant of Arabidopsis with altered steryl-ester metabolism

    International Nuclear Information System (INIS)

    A chilling-sensitive mutant of Arabidopsis thaliana was isolated and subjected to genetic, physiological, and biochemical analysis. The chilling-sensitive nature of the mutant line is due to a single recessive nuclear mutation at a locus designated chs1. In contrast to wild-type plants, which are not adversely affected by low temperatures, the chs1 mutant is killed by several days of exposure to temperatures below 18 degree C. Following exposure to chilling temperatures, the mutant displays two common symptoms of chilling injury - leaf chlorosis and electrolyte leakage. In these respects, the physiological response of the mutant to low temperatures mimics the response observed in some naturally occurring chilling sensitive species. The biochemical basis of chilling sensitivity was explored by examining the pattern of incorporation of 14CO2 into soluble metabolites and lipids in wild-type and mutant plants. The only difference observed between the mutant and wild type was that following low temperature treatment, the mutant accumulated 10-fold more radioactivity in a specific class of neutral lipids which were identified by a variety of criteria to be steryl-esters. The accumulation of radioactivity in the steryl-ester fraction occurs 24 hours before there is any visible evidence of chilling injury

  18. Development of an efficient process for radiation vulcanization of natural rubber latex using hydroperoxide with sensitizers

    International Nuclear Information System (INIS)

    An attempt was made to reduce radiation dose for radiation vulcanization of natural rubber latex. One of the best methods found was to co-vulcanize the latex using partial radiation vulcanization at 4 kGy with 5 phr n-butyl acrylate as sensitizer and 0.1 phr t-butyl hydroperoxide (BHPO) as co-sensitizer followed by redox vulcanization using either 4 phr fructose at temperature of 60 degree C for 3 hours or 0.2 phr BHPO and 0.4 phr tetra-ethylene pentamine (TEPA) at room temperature for I hour. The rubber film obtained had tensile strength of about 25 MPa, modules 300% of 0. 9 MPa and cross link density of about 1. 5 x 10 sup 19 crosslink/cm sup 3. It was noted that the crosslink density of rubber films from the co-vulcanization was the average value of the values obtained by radiation vulcanization and redox vulcanization

  19. Radiation-Induced Epigenetic Alterations after Low and High LET Irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Aypar, Umut; Morgan, William F.; Baulch, Janet E.

    2011-02-01

    Epigenetics, including DNA methylation and microRNA (miRNA) expression, could be the missing link in understanding the delayed, non-targeted effects of radiation including radiationinduced genomic instability (RIGI). This study tests the hypothesis that irradiation induces epigenetic aberrations, which could eventually lead to RIGI, and that the epigenetic aberrations induced by low linear energy transfer (LET) irradiation are different than those induced by high LET irradiations. GM10115 cells were irradiated with low LET x-rays and high LET iron (Fe) ions and evaluated for DNA damage, cell survival and chromosomal instability. The cells were also evaluated for specific locus methylation of nuclear factor-kappa B (NFκB), tumor suppressor in lung cancer 1 (TSLC1) and cadherin 1 (CDH1) gene promoter regions, long interspersed nuclear element 1 (LINE-1) and Alu repeat element methylation, CpG and non-CpG global methylation and miRNA expression levels. Irradiated cells showed increased micronucleus induction and cell killing immediately following exposure, but were chromosomally stable at delayed times post-irradiation. At this same delayed time, alterations in repeat element and global DNA methylation and miRNA expression were observed. Analyses of DNA methylation predominantly showed hypomethylation, however hypermethylation was also observed. MiRNA shown to be altered in expression level after x-ray irradiation are involved in chromatin remodeling and DNA methylation. Different and higher incidence of epigenetic changes were observed after exposure to low LET x-rays than high LET Fe ions even though Fe ions elicited more chromosomal damage and cell killing. This study also shows that the irradiated cells acquire epigenetic changes even though they are chromosomally stable suggesting that epigenetic aberrations may arise in the cell without initiating RIGI.

  20. Pain sensitivity and tactile spatial acuity are altered in healthy musicians as in chronic pain patients.

    Directory of Open Access Journals (Sweden)

    Anna M. eZamorano

    2015-01-01

    Full Text Available Extensive training of repetitive and highly skilled movements, as it occurs in professional classical musicians, may lead to changes in tactile sensitivity and corresponding cortical reorganization of somatosensory cortices. It is also known that professional musicians frequently experience musculoskeletal pain and pain-related symptoms during their careers. The present study aimed at understanding the complex interaction between chronic pain and music training with respect to somatosensory processing. For this purpose, tactile thresholds (mechanical detection, grating orientation, two-point discrimination and subjective ratings to thermal and pressure pain stimuli were assessed in 17 professional musicians with chronic pain, 30 pain-free musicians, 20 non-musicians with chronic pain, and 18 pain-free non-musicians. We found that pain-free musicians displayed greater touch sensitivity (i.e. lower mechanical detection thresholds, lower tactile spatial acuity (i.e., higher grating orientation thresholds and increased pain sensitivity to pressure and heat compared to pain-free non-musicians. Moreover, we also found that musicians and non-musicians with chronic pain presented lower tactile spatial acuity and increased pain sensitivity to pressure and heat compared to pain-free non-musicians. The significant increment of pain sensitivity together with decreased spatial discrimination in pain-free musicians and the similarity of results found in chronic pain patients, suggests that the extensive training of repetitive and highly skilled movements in classical musicians could be considered as a risk factor for developing chronic pain, probably due to use-dependent plastic changes elicited in somatosensory pathways.

  1. The application of comet- and micronucleus-assay for the determination of individual radiation sensitivity

    International Nuclear Information System (INIS)

    There are various fields in which different radiosensitivities of human beings play a crucial role: occupational exposure, radiation accidents, radiotherapy. Fast methods of analysis are required to determine individual radiation sensitivity. Two such methods are used in our institute since several years: micronuclei and comets. The comet assay, in particular, which does not require cell proliferation, was useful in the identification of radiosensitive individuals (e.g. ataxia telangiectasia patients or people who responded with severe side effects to radiotherapy). (orig.)

  2. Novel computational methods for image analysis and quantification using position sensitive radiation detectors

    OpenAIRE

    Sanchez Crespo, Alejandro

    2005-01-01

    The major advantage of position sensitive radiation detector systems lies in their ability to non invasively map the regional distribution of the emitted radiation in real-time. Three of such detector systems were studied in this thesis, gamma-cameras, positron cameras and CMOS image sensors. A number of physical factors associated to these detectors degrade the qualitative and quantitative properties of the obtained images. These blurring factors could be divided into two groups. The first g...

  3. Gadolinium(III) texaphyrin: a tumor selective radiation sensitizer that is detectable by MRI.

    OpenAIRE

    Young, S W; Qing, F; Harriman, A; Sessler, J.L.; Dow, W C; Mody, T D; Hemmi, G W; Hao, Y.; Miller, R. A.

    1996-01-01

    Gadolinium(III) texaphyrin (Gd-tex2+) is representative of a new class of radiation sensitizers detectable by magnetic resonance imaging (MRI). This porphyrin-like complex has a high electron affinity [E1/2 (red.) approximately = -0.08 V versus normal hydrogen electrode] and forms a long-lived pi-radical cation upon exposure to hydrated electrons, reducing ketyl radicals, or superoxide ions. Consistent with these chemical findings, Gd-tex2+ was found to be an efficient radiation sensitizer in...

  4. Increasing sensitivity of quasi-binary media analysis by spectral distribution of gamma-radiation albedo

    International Nuclear Information System (INIS)

    Full text: There has been suggested a method of increasing sensitivity of quasi-binary media analysis based on peculiarities of spectral distribution of gamma-radiation albedo. In quasi-binary media analysis in which there is observed close inter-connection between the effective coefficient of gamma-radiation weakening and heavy component content, it is necessary to obtain the maximum sensitivity of the analytical signal to the parameter being determined. The study showed that in certain geometrical parameters (source-detector distance, air gap between the probe and the medium surface) there is observed the spectrum displacement of the secondary radiation at the medium material composition change. The power distribution displacement of gamma-radiation albedo at the effective coefficient of gamma-radiation weakening change (the medium material composition) is explained by the adequate changing the length of free flight of primary quantum, angle characteristics of scattering and probability of photoelectric absorption of secondary radiation. The essence of the method suggested is in measuring the power corresponding to the maximum in the spectrum of the secondary radiation and the magnitude of gamma-radiation albedo. At the expense of these parameters change at the material composition of the medium analyzed variation there has been obtained the increase of the method contrast range. Depending on the type of the quasi-binary medium (coal, iron ore, carbonate raw materials) there have been determined optimal condition (primary radiation power, probe geometrical parameters) at which there is observed the maximum linear displacement of the power corresponding to the maximum in the secondary radiation spectrum and chosen the power intervals for normal magnitude of gamma-radiation albedo. The method is recommended to analyze raw and industrial materials of quasi-binary composition in which there is observed close correlation dependence between their effective atomic

  5. n-butyl acrylate as a sensitizer for radiation vulcanization of natural rubber latex

    International Nuclear Information System (INIS)

    As a sensitizer for radiation vulcanization of NR latex n-butyl acrylate (n-BA) has several advantages such as high sensitizing efficiency and easiness of removal of residue by drying. However n-BA tends to destabilize NR latex. A study to stabilize NR latex against n-BA has been carried out. The most effective stabilizer is potassium hydroxide. By the addition of 0.2 phr KOH the stability of NR latex is sufficiently improved to withstand the addition of 5 phr n-BA. The sensitizing efficiency of n-BA is so high that the vulcanization dose is 15 kGy with 5 phr n-BA without the addition of carbon tetrachloride as a co-sensitizer. The radiation vulcanized NR latex has enough stability for a 90 days storage. (author)

  6. Impact of ultraviolet-B radiation on planktonic fish larvae: Alteration of the osmoregulatory function

    Energy Technology Data Exchange (ETDEWEB)

    Sucre, Elliott, E-mail: elliott.sucre@univ-montp2.fr [AEO Team (Adaptation Ecophysiologique et Ontogenese), UMR 5119 Ecosym UM2, CNRS, IRD, Ifremer, UM1, Universite Montpellier 2, cc092, Pl. Eugene Bataillon, 34095 Montpellier, Cx 05 (France); Vidussi, Francesca [RESEAUX Team (Reseaux Planctoniques et Changement Environnemental), UMR 5119 Ecosym UM2, CNRS, IRD, Ifremer, UM1, Universite Montpellier 2, cc093, Pl. Eugene Bataillon, 34095 Montpellier, Cx 05 (France); Mostajir, Behzad [RESEAUX Team (Reseaux Planctoniques et Changement Environnemental), UMR 5119 Ecosym UM2, CNRS, IRD, Ifremer, UM1, Universite Montpellier 2, cc093, Pl. Eugene Bataillon, 34095 Montpellier, Cx 05 (France); Centre d' ecologie marine experimentale MEDIMEER (Mediterranean centre for Marine Ecosystem Experimental Research), Universite Montpellier 2-CNRS (UMS 3301), Station Mediterraneenne de l' Environnement Littoral, MEDIMEER, 2 Rue des Chantiers, 34200 Sete (France); Charmantier, Guy; Lorin-Nebel, Catherine [AEO Team (Adaptation Ecophysiologique et Ontogenese), UMR 5119 Ecosym UM2, CNRS, IRD, Ifremer, UM1, Universite Montpellier 2, cc092, Pl. Eugene Bataillon, 34095 Montpellier, Cx 05 (France)

    2012-03-15

    Coastal marine ecosystems are submitted to variations of several abiotic and biotic parameters, some of them related to global change. Among them the ultraviolet-B (UV-B) radiation (UVBR: 280-320 nm) may strongly impact planktonic fish larvae. The consequences of an increase of UVBR on the osmoregulatory function of Dicentrarchus labrax larvae have been investigated in this study. In young larvae of D. labrax, as in other teleosts, osmoregulation depends on tegumentary ion transporting cells, or ionocytes, mainly located on the skin of the trunk and of the yolk sac. As early D. labrax larvae passively drift in the top water column, ionocytes are exposed to solar radiation. The effect of UVBR on larval osmoregulation in seawater was evaluated through nanoosmometric measurements of the blood osmolality after exposure to different UV-B treatments. A loss of osmoregulatory capability occured in larvae after 2 days of low (50 {mu}W cm{sup -2}: 4 h L/20 h D) and medium (80 {mu}W cm{sup -2}: 4 h L/20 h D) UVBR exposure. Compared to control larvae kept in the darkness, a significant increase in blood osmolality, abnormal behavior and high mortalities were detected in larvae exposed to UVBR from 2 days on. At the cellular level, an important decrease in abundance of tegumentary ionocytes and mucous cells was observed after 2 days of exposure to UVBR. In the ionocytes, two major osmoeffectors were immunolocalized, the Na{sup +}/K{sup +}-ATPase and the Na{sup +}/K{sup +}/2Cl{sup -} cotransporter. Compared to controls, the fluorescent immunostaining was lower in UVBR-exposed larvae. We hypothesize that the impaired osmoregulation in UVBR-exposed larvae originates from the lower number of tegumentary ionocytes and mucous cells. This alteration of the osmoregulatory function could negatively impact the survival of young larvae at the surface water exposed to UVBR.

  7. Impact of ultraviolet-B radiation on planktonic fish larvae: Alteration of the osmoregulatory function

    International Nuclear Information System (INIS)

    Coastal marine ecosystems are submitted to variations of several abiotic and biotic parameters, some of them related to global change. Among them the ultraviolet-B (UV-B) radiation (UVBR: 280–320 nm) may strongly impact planktonic fish larvae. The consequences of an increase of UVBR on the osmoregulatory function of Dicentrarchus labrax larvae have been investigated in this study. In young larvae of D. labrax, as in other teleosts, osmoregulation depends on tegumentary ion transporting cells, or ionocytes, mainly located on the skin of the trunk and of the yolk sac. As early D. labrax larvae passively drift in the top water column, ionocytes are exposed to solar radiation. The effect of UVBR on larval osmoregulation in seawater was evaluated through nanoosmometric measurements of the blood osmolality after exposure to different UV-B treatments. A loss of osmoregulatory capability occured in larvae after 2 days of low (50 μW cm−2: 4 h L/20 h D) and medium (80 μW cm−2: 4 h L/20 h D) UVBR exposure. Compared to control larvae kept in the darkness, a significant increase in blood osmolality, abnormal behavior and high mortalities were detected in larvae exposed to UVBR from 2 days on. At the cellular level, an important decrease in abundance of tegumentary ionocytes and mucous cells was observed after 2 days of exposure to UVBR. In the ionocytes, two major osmoeffectors were immunolocalized, the Na+/K+-ATPase and the Na+/K+/2Cl− cotransporter. Compared to controls, the fluorescent immunostaining was lower in UVBR-exposed larvae. We hypothesize that the impaired osmoregulation in UVBR-exposed larvae originates from the lower number of tegumentary ionocytes and mucous cells. This alteration of the osmoregulatory function could negatively impact the survival of young larvae at the surface water exposed to UVBR.

  8. Effect of ionizing radiation on properties of acrylic pressure sensitive adhesives

    International Nuclear Information System (INIS)

    Pressure-sensitive adhesives for technical application are widely produced. The biological properties of adhesives depend on the type of monomers used. The available literature data as experience of the authors of this study in the area of pressure-sensitive acrylic adhesive, polymers used in medicine, polymerisation in aqueous media, radiation sterilization, permit to make an assumption that it is possible to elaborate the technology of production of pressure-sensitive adhesives in aqueous emulsion for medical applications. Identification of phenomena influencing the adhesive properties, especially its adhesion, cohesion, tack and durability is of great importance. The control of polymer structure is performed by means of adequate selection of conditions of synthesis and parameters of radiation processing. The authors investigate the influence on the final products of such factors as the type and amount of monomers used, their mutual ratio, as well as the ratio monomers and the dose of ionising radiation. There is no available literature information concerning the investigation of resistance of acrylic emulsion adhesive to sterilisation by electron beam. It is known from unpublished research that some adhesives are resistant to radiation, while others undergo destruction. It probably depends on the composition of emulsion, specifically on the additives which modify adhesives. Simultaneous achievement of good cohesion and adhesion in the case of such types of pressure sensitive adhesives is very difficult pressure sensitive adhesives is very difficult

  9. Phloem-specific expression of a melon Aux/IAA in tomato plants alters auxin sensitivity and plant development

    Directory of Open Access Journals (Sweden)

    Guy eGolan

    2013-08-01

    Full Text Available Phloem sap contains a large repertoire of macromolecules in addition to sugars, amino acids, growth substances and ions. The transcription profile of melon phloem sap contains over 1,000 mRNA molecules, most of them associated with signal transduction, transcriptional control, and stress and defense responses. Heterografting experiments have established the long-distance trafficking of numerous mRNA molecules. Interestingly, several trafficking transcripts are involved in the auxin response, including two molecules coding for auxin/indole acetic acid (Aux/IAA. To further explore the biological role of the melon Aux/IAA transcript CmF-308 in the vascular tissue, a cassette containing the coding sequence of this gene under a phloem-specific promoter was introduced into tomato plants. The number of lateral roots was significantly higher in transgenic plants expressing CmF-308 under the AtSUC2 promoter than in controls. A similar effect on root development was obtained after transient expression of CmF-308 in source leaves of N. benthamiana plants. An auxin-response assay showed that CmF-308-transgenic roots are more sensitive to auxin than control roots. In addition to the altered root development, phloem-specific expression of CmF-308 resulted in shorter plants, a higher number of lateral shoots and delayed flowering, a phenotype resembling reduced apical dominance. In contrast to the root response, cotyledons of the transgenic plants were less sensitive to auxin than control cotyledons. The reduced auxin sensitivity in the shoot tissue was confirmed by lower relative expression of several Aux/IAA genes in leaves and an increase in the relative expression of a cytokinin-response regulator, TRR8/9b. The accumulated data suggest that expression of Aux/IAA in the phloem modifies auxin sensitivity in a tissue-specific manner, thereby altering plant development.

  10. Stat1 activation attenuates IL-6 induced Stat3 activity but does not alter apoptosis sensitivity in multiple myeloma

    Directory of Open Access Journals (Sweden)

    Dimberg Lina Y

    2012-07-01

    Full Text Available Abstract Background Multiple myeloma (MM is at present an incurable malignancy, characterized by apoptosis-resistant tumor cells. Interferon (IFN treatment sensitizes MM cells to Fas-induced apoptosis and is associated with an increased activation of Signal transducer and activator of transcription (Stat1. The role of Stat1 in MM has not been elucidated, but Stat1 has in several studies been ascribed a pro-apoptotic role. Conversely, IL-6 induction of Stat3 is known to confer resistance to apoptosis in MM. Methods To delineate the role of Stat1 in IFN mediated sensitization to apoptosis, sub-lines of the U-266-1970 MM cell line with a stable expression of the active mutant Stat1C were utilized. The influence of Stat1C constitutive transcriptional activation on endogenous Stat3 expression and activation, and the expression of apoptosis-related genes were analyzed. To determine whether Stat1 alone would be an important determinant in sensitizing MM cells to apoptosis, the U-266-1970-Stat1C cell line and control cells were exposed to high throughput compound screening (HTS. Results To explore the role of Stat1 in IFN mediated apoptosis sensitization of MM, we established sublines of the MM cell line U-266-1970 constitutively expressing the active mutant Stat1C. We found that constitutive nuclear localization and transcriptional activity of Stat1 was associated with an attenuation of IL-6-induced Stat3 activation and up-regulation of mRNA for the pro-apoptotic Bcl-2 protein family genes Harakiri, the short form of Mcl-1 and Noxa. However, Stat1 activation alone was not sufficient to sensitize cells to Fas-induced apoptosis. In a screening of > 3000 compounds including bortezomib, dexamethasone, etoposide, suberoylanilide hydroxamic acid (SAHA, geldanamycin (17-AAG, doxorubicin and thalidomide, we found that the drug response and IC50 in cells constitutively expressing active Stat1 was mainly unaltered. Conclusion We conclude that Stat1 alters IL-6

  11. Sorption of redox sensitive actinides onto granite and altered material from AESPOE HRL

    International Nuclear Information System (INIS)

    Sorption experiments with redox sensitive actinide elements such as Pu, Np and U as well as the fission product Tc are performed onto fracture filling material, which are obtained from Aespoe Hard Rock Laboratory. Migration experiments using these elements showed a complex retention pattern along the flow path. For this reason a new SEM/EDX analysis technique was applied for identification retaining mineral phases. From previous investigations, it is known that Np(V) is retained by reduction to Np(IV) in the presence of Fe(II) minerals. Sorption of U is also strongly correlated with the occurrence of Fe oxide phases. The retention mechanism onto Fe(II) phases is evaluated for Np but is not yet confirmed for U and Tc. These tracer concentrations were too low along the flow path. Additionally, the internal surface areas of the fracture play a dominating role for retaining the redox sensitive radionuclides

  12. Can OCT be sensitive to nanoscale structural alterations in biological tissue?

    OpenAIRE

    Yi, Ji; Radosevich, Andrew J.; Rogers, Jeremy D.; Norris, Sam C.P.; Çapoğlu, İlker R.; Taflove, Allen; Backman, Vadim

    2013-01-01

    Exploration of nanoscale tissue structures is crucial in understanding biological processes. Although novel optical microscopy methods have been developed to probe cellular features beyond the diffraction limit, nanometer-scale quantification remains still inaccessible for in situ tissue. Here we demonstrate that, without actually resolving specific geometrical feature, OCT can be sensitive to tissue structural properties at the nanometer length scale. The statistical mass-density distributio...

  13. Amphetamine sensitization alters reward processing in the human striatum and amygdala.

    Directory of Open Access Journals (Sweden)

    Owen G O'Daly

    Full Text Available Dysregulation of mesolimbic dopamine transmission is implicated in a number of psychiatric illnesses characterised by disruption of reward processing and goal-directed behaviour, including schizophrenia, drug addiction and impulse control disorders associated with chronic use of dopamine agonists. Amphetamine sensitization (AS has been proposed to model the development of this aberrant dopamine signalling and the subsequent dysregulation of incentive motivational processes. However, in humans the effects of AS on the dopamine-sensitive neural circuitry associated with reward processing remains unclear. Here we describe the effects of acute amphetamine administration, following a sensitising dosage regime, on blood oxygen level dependent (BOLD signal in dopaminoceptive brain regions during a rewarded gambling task performed by healthy volunteers. Using a randomised, double-blind, parallel-groups design, we found clear evidence for sensitization to the subjective effects of the drug, while rewarded reaction times were unchanged. Repeated amphetamine exposure was associated with reduced dorsal striatal BOLD signal during decision making, but enhanced ventromedial caudate activity during reward anticipation. The amygdala BOLD response to reward outcomes was blunted following repeated amphetamine exposure. Positive correlations between subjective sensitization and changes in anticipation- and outcome-related BOLD signal were seen for the caudate nucleus and amygdala, respectively. These data show for the first time in humans that AS changes the functional impact of acute stimulant exposure on the processing of reward-related information within dopaminoceptive regions. Our findings accord with pathophysiological models which implicate aberrant dopaminergic modulation of striatal and amygdala activity in psychosis and drug-related compulsive disorders.

  14. Adverse challenges in the perinatal period may alter nociceptive sensitivity in later life

    OpenAIRE

    Gooding, Hayley Louise

    2010-01-01

    Chronic inflammatory and neuropathic pain states are poorly understood, and currently inadequately treated. Clinically, the symptoms of such pain states include allodynia (interpretation of innocuous stimuli as noxious), hyperalgesia (increased sensitivity to noxious stimuli) and spontaneous (non-evoked) pain. Additionally, chronic pain states are often associated with affective disorders such as anxiety and depression which can further reduce the individual’s quality of life. ...

  15. Proximity to Delivery Alters Insulin Sensitivity and Glucose Metabolism in Pregnant Mice

    OpenAIRE

    Musial, Babara; Fernandez-Twinn, Denise S.; Owen R Vaughan; Ozanne, Susan E.; Voshol, Peter; Sferruzzi-Perri, Amanda N.; Fowden, Abigail L.

    2016-01-01

    In late pregnancy, maternal insulin resistance occurs to support fetal growth but little is known about insulin-glucose dynamics close to delivery. This study measured insulin sensitivity in mice in late pregnancy, day (D) 16, and near term, D19, (term 20.5D). Non-pregnant (NP) and pregnant mice were assessed for metabolite and hormone concentrations, body composition by dual energy X-ray absorptiometry, tissue insulin signalling protein abundance by Western blotting, glucose tolerance and ut...

  16. High temperature, drought and their interaction induced protein alterations in sensitive and tolerant wheat varieties

    OpenAIRE

    Vikender Kaur, Reena Mahla And R.K.Behl

    2014-01-01

    Two contrasting wheat (Triticum aestivum L.) cultivars WH730 (high temperature tolerant) and UP2565 (high temperature sensitive) were tested for differential response to combined and individually applied high temperature (HT) and drought (D) stress at seedling stage for peptide profile. Initial profile of the stress induced peptides was outlined via SDS electrophoresis of leaf extracts. Electrophoretic pattern of proteins revealed expression of new bands as well as disappearance of certain ot...

  17. Comparative study of different surrogate markers for individual radiation sensitivity; Vergleichende Untersuchung verschiedener Surrogatmarker der individuellen zellulaeren Strahlenempfindlichkeit

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, Nele Julia

    2013-12-17

    Radiotherapy is an important part of therapeutic tumor treatment concept. The applied total dose is limited by the unavoidable radiation effect on the surrounding normal tissue and the risk of radiation induced acute or chronic side effects. The clinical radiation sensitivity, i.e. the risk of radiogenic side effects is strongly coupled to the cellular radiation sensitivity. The contribution is focused on the development of a predictive tool for the individual radiation sensitivity for individual radiotherapeutic planning using lymphocytes. Residual foci, i.e. accumulated repair associated proteins at the residual double strand break are supposed to be surrogate markers of the cellular radiation sensitivity. No relation between the foci detection and the G(0)/G(1) was found assay with respect to the individual radiation sensitivity.

  18. Can OCT be sensitive to nanoscale structural alterations in biological tissue?

    Science.gov (United States)

    Yi, Ji; Radosevich, Andrew J; Rogers, Jeremy D; Norris, Sam C P; Çapoğlu, İlker R; Taflove, Allen; Backman, Vadim

    2013-04-01

    Exploration of nanoscale tissue structures is crucial in understanding biological processes. Although novel optical microscopy methods have been developed to probe cellular features beyond the diffraction limit, nanometer-scale quantification remains still inaccessible for in situ tissue. Here we demonstrate that, without actually resolving specific geometrical feature, OCT can be sensitive to tissue structural properties at the nanometer length scale. The statistical mass-density distribution in tissue is quantified by its autocorrelation function modeled by the Whittle-Mateŕn functional family. By measuring the wavelength-dependent backscattering coefficient μb(λ) and the scattering coefficient μs, we introduce a technique called inverse spectroscopic OCT (ISOCT) to quantify the mass-density correlation function. We find that the length scale of sensitivity of ISOCT ranges from ~30 to ~450 nm. Although these sub-diffractional length scales are below the spatial resolution of OCT and therefore not resolvable, they are nonetheless detectable. The sub-diffractional sensitivity is validated by 1) numerical simulations; 2) tissue phantom studies; and 3) ex vivo colon tissue measurements cross-validated by scanning electron microscopy (SEM). Finally, the 3D imaging capability of ISOCT is demonstrated with ex vivo rat buccal and human colon samples. PMID:23571994

  19. Behavioral sensitization and long-term neurochemical alterations associated with the fungicide triadimefon.

    Science.gov (United States)

    Reeves, Ruth; Thiruchelvam, Mona; Richfield, Eric K; Cory-Slechta, Deborah A

    2003-09-01

    Triadimefon (TDF), a widely used triazole fungicide, blocks reuptake of the neurotransmitter dopamine (DA), similarly to cocaine. Preliminary studies show that intermittent intraperitoneal injections of TDF increase ambulatory and vertical activity across repeated injections [Neurotoxicology (in press)] leading to the hypothesis tested here, that exposure to TDF may influence the development and expression of behavioral sensitization, a model of psychostimulant-induced psychosis. Exposure of adult male C57BL/6 mice to 75 mg/kg i.p. TDF (TDF75) twice a week for 7 weeks increased vertical activity at each injection. Following a 2-week withdrawal period, a TDF challenge to test for expression of behavioral sensitization revealed further increases in vertical activity levels relative to all other conditions. TDF induction/expression of behavioral sensitization was associated with long-term, perhaps permanent modulation of dopaminergic function that included increases in striatal dihydroxyphenylacetic acid (DOPAC) and DA turnover, increases in medial prefrontal cortex (mPFC) dopamine transporter (DAT) binding, as well as decreases in DA D1 and increases in DA D2 and DAT receptor binding that appeared to target the nucleus accumbens shell (NAs) subregion. Thus, TDF exposure may serve as an environmental risk factor for DA system dysfunctions. PMID:14592684

  20. Methods and tools for the evaluation of the sensitivity to natural radiations of advanced integrated circuits

    International Nuclear Information System (INIS)

    Atmospheric neutrons, whose fluxes and energies dependent on the altitude, the sun activity and the geographic coordinates, have been identified as being capable to provoke SEE (Single Event Effects), by indirect ionisation, in integrated devices issued from advanced manufacturing processes (nano-metric devices). This concerns not only avionics but also applications operating at ground level. The evaluation of the sensitivity to SEE provoked by natural radiation becomes thus a mandatory step during the selection of devices devoted to be included in applications requiring high reliability. The sensitivity to SEE can be mitigated by different approaches at different levels from manufacturing level (use of particular process technologies such as SOI - Silicon On Isolator -) to the system level (hardware/software redundancy). Independently of the adopted hardening approach, the so-called radiation ground testing are mandatory to evaluate the error rates of a device or a system. During such tests, the DUT (Device Under Test) is exposed to a flux of particles while it performs a given activity. For SEU (Single Event Upsets) radiation ground testing, two main strategies exist: static test: the circuit areas which are supposed to be sensitive to SEUs (registers, memories,...) are initialized with a reference pattern. The content of the sensitive area is periodically compared to the reference pattern to identify potential SEU. Dynamic test: the DUT performs an activity representative of the one it will execute during the final application. Static test: strategies are frequently adopted as they provide the intrinsic sensitivity, in terms of the average number of particles needed to provoke an SEU, of different sensitive areas of the device. From such a strategy can thus be obtained a 'worst case estimation' of the device sensitivity. This thesis aims at giving a description and validating the methodologies required to estimate the sensitivity to radiations of two types of

  1. Potential sensitivity of photosynthesis and isoprene emission to direct radiative effects of atmospheric aerosol pollution

    OpenAIRE

    2015-01-01

    A global Earth system model is applied to quantify the impacts of direct anthropogenic aerosol effective radiative forcing on gross primary productivity (GPP) and isoprene emission. The impacts of different pollution aerosol sources (all anthropogenic, biomass burning and non-biomass burning) are investigated by performing sensitivity experiments. On the global scale, our results show that land carbon fluxes (GPP and isoprene emission) are not sensitive to pollution aerosols...

  2. Research on relation between professional radiation length of service with radioactive sensitivity parameters of working personnel

    International Nuclear Information System (INIS)

    Objective: To find out infection of professional radiation on radioactive working personnel, and offer pertinence advise and gist for constituting radioactive protection measure. Methods: through epidemiological diagnoses, observe, study and analyse three radiation sensitivity parameters of 912 people. Results: ophthalmological abnormity rate increase along with length of service; outer hemogram and chromosome aberration rate does not increase along with the length of service all the time, but drops from 15a. Conclution: there is a certain infection of professional radiation on the health of working personnel, and we can constitute to take more logical protective measure. (authors)

  3. Influence of Monosodium Glutamate on Radiation-Induced Biochemical Alterations in Male Albino Rats

    International Nuclear Information System (INIS)

    no effect on insulin resistance and their co-administration produces an additive effect compared to each single treatment. Regarding lipid profile, MSG as well as RAD-exposure induced hyperlipidaemia more noticeable in case of irradiation. Their co-administration had potentiated hyperlipidaemia compared to each single treatment. It is concluded that exposure to MSG together with RAD increased oxidative stress and neurotransmitter alteration in the brain and the risk of metabolic syndrome. It is thus recommended to limit the intake of MSG when human are at risk of overexposure to ionizing radiation.

  4. Alteration in transcription factor binding in murine thymocytes after low dose radiation

    International Nuclear Information System (INIS)

    Objective: To study the effect of low dose radiation on gene transcription regulation of murine thymocytes. Methods: Alteration in transcription factor binding in murine thymocytes 4 h after whole body irradiation (WBI) with 75 mGy X-rays was investigated with gel mobility shift assay. Results: Increased binding to CREB, NF-kB and APl consensus sequences was found with nuclear extracts prepared from thymocytes of irradiated versus sham-irradiated mice. Binding to the CREB, NF-kB and APl consensus sequences by nuclear extracts derived from irradiated mice was 6-fold, 4,3-fold and 2-fold higher than that from sham-irradiated respectively. The present report demonstrates that WBI with 75 mGy X-rays is capable of increasing expression of CREB, NF-kB and APl in murine thymocytes. competition with the cold oligonucleotide containing the consensus sequences for CREB and NF-kB resulted in loss of the shifted band, indicating specific binding. Conclusions: X-ray activation of select transcription factors, which bind certain consensus sites in promoters, may cause specific induction of gene transcription

  5. Chronic radiation-induced leukemogenesis: alterations of hematopoietic progenitor repair functions during preclinical phases

    International Nuclear Information System (INIS)

    Chronic exposure to low daily doses of whole-body gamma irradiation elicits a high incidence of myeloid leukemia (ML) and related myeloproliferative diseases (MPD) in beagles. Previously, the authors identified and partially characterized a four-phase sequence of evolving MPD as a consequence of chronic radiation exposure. With a focus on preclinical alterations in granulocyte/monocyte-committed stem cells, they have identified two critical events in the process: (i) an early event, involving the coupling of acquired radioresistance of the stem cell with renewed proliferative capacity; and (ii) a late event, involving acquired autocrine functions and associated change in stem cell clonality. In terms of the early event, repair-associated parameters are currently being examined on the cellular level by both split-dose and low dose-rate-type assays with survival enhancement used as the measured end point. On the molecular level, these parameters are examined by microfluorometric alkaline elution assays with DNA damage and repair used as end points

  6. Radiation-Induced Alterations in Mouse Brain Development Characterized by Magnetic Resonance Imaging

    International Nuclear Information System (INIS)

    Purpose: The purpose of this study was to identify regions of altered development in the mouse brain after cranial irradiation using longitudinal magnetic resonance imaging (MRI). Methods and Materials: Female C57Bl/6 mice received a whole-brain radiation dose of 7 Gy at an infant-equivalent age of 2.5 weeks. MRI was performed before irradiation and at 3 time points following irradiation. Deformation-based morphometry was used to quantify volume and growth rate changes following irradiation. Results: Widespread developmental deficits were observed in both white and gray matter regions following irradiation. Most of the affected brain regions suffered an initial volume deficit followed by growth at a normal rate, remaining smaller in irradiated brains compared with controls at all time points examined. The one exception was the olfactory bulb, which in addition to an early volume deficit, grew at a slower rate thereafter, resulting in a progressive volume deficit relative to controls. Immunohistochemical assessment revealed demyelination in white matter and loss of neural progenitor cells in the subgranular zone of the dentate gyrus and subventricular zone. Conclusions: MRI can detect regional differences in neuroanatomy and brain growth after whole-brain irradiation in the developing mouse. Developmental deficits in neuroanatomy persist, or even progress, and may serve as useful markers of late effects in mouse models. The high-throughput evaluation of brain development enabled by these methods may allow testing of strategies to mitigate late effects after pediatric cranial irradiation.

  7. Radiation-Induced Alterations in Mouse Brain Development Characterized by Magnetic Resonance Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Gazdzinski, Lisa M.; Cormier, Kyle [Mouse Imaging Centre, Hospital for Sick Children, Toronto (Canada); Lu, Fred G. [Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto (Canada); Lerch, Jason P. [Mouse Imaging Centre, Hospital for Sick Children, Toronto (Canada); Department of Medical Biophysics, University of Toronto, Toronto (Canada); Wong, C. Shun [Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto (Canada); Department of Medical Biophysics, University of Toronto, Toronto (Canada); Department of Radiation Oncology, University of Toronto, Toronto (Canada); Nieman, Brian J., E-mail: bjnieman@phenogenomics.ca [Mouse Imaging Centre, Hospital for Sick Children, Toronto (Canada); Department of Medical Biophysics, University of Toronto, Toronto (Canada)

    2012-12-01

    Purpose: The purpose of this study was to identify regions of altered development in the mouse brain after cranial irradiation using longitudinal magnetic resonance imaging (MRI). Methods and Materials: Female C57Bl/6 mice received a whole-brain radiation dose of 7 Gy at an infant-equivalent age of 2.5 weeks. MRI was performed before irradiation and at 3 time points following irradiation. Deformation-based morphometry was used to quantify volume and growth rate changes following irradiation. Results: Widespread developmental deficits were observed in both white and gray matter regions following irradiation. Most of the affected brain regions suffered an initial volume deficit followed by growth at a normal rate, remaining smaller in irradiated brains compared with controls at all time points examined. The one exception was the olfactory bulb, which in addition to an early volume deficit, grew at a slower rate thereafter, resulting in a progressive volume deficit relative to controls. Immunohistochemical assessment revealed demyelination in white matter and loss of neural progenitor cells in the subgranular zone of the dentate gyrus and subventricular zone. Conclusions: MRI can detect regional differences in neuroanatomy and brain growth after whole-brain irradiation in the developing mouse. Developmental deficits in neuroanatomy persist, or even progress, and may serve as useful markers of late effects in mouse models. The high-throughput evaluation of brain development enabled by these methods may allow testing of strategies to mitigate late effects after pediatric cranial irradiation.

  8. Radiation dose-rate meter using an energy-sensitive counter

    International Nuclear Information System (INIS)

    A radiation dose-rate meter is described comprising: an energy-sensitive radiation detecting element which generates at an output thereof ionization current pulses having an amplitude proportional to the charge quanta deposited in the radiation detecting element by detected photons of ionizing radiation; a charge-sensitive preamplifier connected to the output of the radiation detecting element; a filter amplifier having a selected filter time constant for generating fixed width pulses at an output thereof in response to each of the step voltage pulses from the preamplifier having an amplitude proportional to the amplitude of each of the step voltage pulses applied to an input thereof; a multi-level discriminator means responsive to the voltage pulses at the output of the filter amplifier for generating a train of count pulses at an output thereof in response to each of the fixed width pulses; and a count rate meter means connected to the output of the multi-level discriminator means of registering the count pulses of each of the train of count pulses as a quantized measure of the radiation dose-rate per unit time of the detected photons of ionizing radiation

  9. Comparison of two different techniques on the human lymphocytes morphology and sensitivity to gamma radiation

    International Nuclear Information System (INIS)

    The lymphocytes in the peripheral blood are divided into two main subclasses: T cells and B cells. These differ from each other in function and in their sensitivity to radiation. The effort to study which group is more sensitive to radiation has resulted in many contradictory results. In the present study we examined whether the methods that are used to separate the lymphocytes from the whole blood, before their separation into subclasses, have an effect on the cells and whether this might contribute to the contradictory results. Blood samples were taken from several normal donors and each sample was devided into two fractions. Lymphocytes in each fraction were separated by one of the two following methods: a) sedimentation of erythrocytes by gravitation; b) separation on Ficoll-Paque density gradient. For cells obtained by these two methods, the ultrastructure was examined by electron microscopy and their ability to incorporate radioactive thymidine was measured. Samples separated on Ficoll-Paque showed a subpopulation with morphological changes similar to those occuring in lymphocytes undergoing stimulation. Unstimulated cells separated on Ficoll-Paque showed greater sensitivity to radiation. The effect of gamma radiation on the capability of lymphocytes to undergo transformation in response to three mitogens; PHA, PWM and Con A was examined. Different mitogens stimulate different lymphocytes subpopulations. There was no difference between the two separation methods regarding the sensitivity to gamma radiation of stimulation by PAH and PWM. The transformation by Con A of lymphocytes separated on Ficoll-Paque was more radiosensitive. This could indicate that the separation by Ficoll-Paque density gradient causes a selective depletion of T lymphocytes that react with Con A and are considered more radioresistant. The use of different methods for separating lymphocytes from whole blood- each has a different influence on the cells- can contribute to contradictory

  10. Effect of protein kinase C inhibitor (PKCI) on radiation sensitivity and c-fos transcription activity

    International Nuclear Information System (INIS)

    The human genetic disorder ataxia-telangiectasia (AT) is a multisystem disease characterized by extreme radiosensitivity. The recent identification of the gene mutated in AT, ATM, and the demonstration that it encodes a homologous domain of phosphatidylinositol 3-kinase (PI3-K), the catalytic subunit of an enzyme involved in transmitting signals from the cell surface to the nucleus, provide support for a role of this gene in signal transduction. Although ionizing radiation was known to induce c-fos transcription, nothing is known about how ATM or PKCI mediated signal transduction pathway modulates the c-fos gene transcription and gene expression. Here we have studied the effect of PKCI on radiation sensitivity and c-fos transcription in normal and AT cells. Normal (LM217) and AT (AT58IVA) cells were transfected with PKCI expression plasmid and the overexpression and integration of PKCI was evaluated by northern blotting and polymerase chain reaction, respectively. 5 Gy of radiation was exposed to LM and AT cells transfected with PKCI expression plasmid and cells were harvested 48 hours after radiation and investigated apoptosis with TUNEL method. The c-fos transcription activity was studied by performing CAT assay of reporter gene after transfection of c-fos CAT plasmid into AT and LM cells. Our results demonstrate for the first time a role of PKCI on. the radiation sensitivity and c-fos expression in LM and AT cells. PKCI increased radiation induced apoptosis in LM cells but reduced apoptosis in AT cells. The basal c-fos transcription activity is 70 times lower in AT cells than that in LM cells. The c-fos transcription activity was repressed by overexpression of PKCI in LM cells but not in AT cells. After induction of c-fos by Ras protein, overexpression of PKCI repressed c-fos transcription in LM cells but not in AT cells. Overexpression of PKCI increased radiation sensitivity and repressed c-fos transcription in LM cells but not in AT cells. The results may be a

  11. Contrasting above- and belowground sensitivity of three Great Plains grasslands to altered rainfall regimes.

    Science.gov (United States)

    Wilcox, Kevin R; von Fischer, Joseph C; Muscha, Jennifer M; Petersen, Mark K; Knapp, Alan K

    2015-01-01

    Intensification of the global hydrological cycle with atmospheric warming is expected to increase interannual variation in precipitation amount and the frequency of extreme precipitation events. Although studies in grasslands have shown sensitivity of aboveground net primary productivity (ANPP) to both precipitation amount and event size, we lack equivalent knowledge for responses of belowground net primary productivity (BNPP) and NPP. We conducted a 2-year experiment in three US Great Plains grasslands--the C4-dominated shortgrass prairie (SGP; low ANPP) and tallgrass prairie (TGP; high ANPP), and the C3-dominated northern mixed grass prairie (NMP; intermediate ANPP)--to test three predictions: (i) both ANPP and BNPP responses to increased precipitation amount would vary inversely with mean annual precipitation (MAP) and site productivity; (ii) increased numbers of extreme rainfall events during high-rainfall years would affect high and low MAP sites differently; and (iii) responses belowground would mirror those aboveground. We increased growing season precipitation by as much as 50% by augmenting natural rainfall via (i) many (11-13) small or (ii) fewer (3-5) large watering events, with the latter coinciding with naturally occurring large storms. Both ANPP and BNPP increased with water addition in the two C4 grasslands, with greater ANPP sensitivity in TGP, but greater BNPP and NPP sensitivity in SGP. ANPP and BNPP did not respond to any rainfall manipulations in the C3 -dominated NMP. Consistent with previous studies, fewer larger (extreme) rainfall events increased ANPP relative to many small events in SGP, but event size had no effect in TGP. Neither system responded consistently above- and belowground to event size; consequently, total NPP was insensitive to event size. The diversity of responses observed in these three grassland types underscores the challenge of predicting responses relevant to C cycling to forecast changes in precipitation regimes even

  12. Ascorbate-Glutathione Cycle Alteration in Cadmium Sensitive Rice Mutant cadB-1

    Institute of Scientific and Technical Information of China (English)

    SHEN Guo-ming; ZHU Cheng; DU Qi-zhen; SHANGGUAN Li-na

    2012-01-01

    A rice cadmium (Cd) sensitive mutant cadB-1 was obtained using Agrobacterium tumefaciens mediated system.After exposure of cadB-1 and wild type (WT) rice seedlings to a range of Cd concentrations for 10 d,Cd accumulated to higher levels in roots,stems and leaves of both cadB-1 and WT with increasing external Cd concentrations,and the inhibition of seedling growth in cadB-1 was more serious than in WT.Hydrogen peroxide accumulation was higher in leaves and roots of cadB-1.The ratios of reduced glutathione (GSH)/oxidized glutathione (GSSG),ascorbate (ASC)/dehydroascorbate (DHA) and reduced nicotinamide adenine dinucleotide phosphate (NADPH)/oxidized nicotinamide adenine dinucleotide phosphate (NADP+) were lower in cadB-1 than in WT both in leaves and roots under high Cd levels.The activities of ascorbate peroxidase (APX),glutathione peroxidase (GR),dehydroascorbate reductase (DHAR) and monodehydroascorbate reductase (MDHAR) were also lower in cadB-1 than in WT both in leaves and roots under the treatment of high levels of Cd.Our results suggest that under Cd stress,the ASC-GSH cycle was more seriously inhibited in cadB-1 than in WT,indicating that the mutant cadB-1 is less able to scavenge reactive oxygen species and sensitive to Cd.

  13. Alterations of Mitochondrial Function and Insulin Sensitivity in Human Obesity and Diabetes Mellitus.

    Science.gov (United States)

    Koliaki, Chrysi; Roden, Michael

    2016-07-17

    Mitochondrial function refers to a broad spectrum of features such as resting mitochondrial activity, (sub)maximal oxidative phosphorylation capacity (OXPHOS), and mitochondrial dynamics, turnover, and plasticity. The interaction between mitochondria and insulin sensitivity is bidirectional and varies depending on tissue, experimental model, methodological approach, and features of mitochondrial function tested. In human skeletal muscle, mitochondrial abnormalities may be inherited (e.g., lower mitochondrial content) or acquired (e.g., impaired OXPHOS capacity and plasticity). Abnormalities ultimately lead to lower mitochondrial functionality due to or resulting in insulin resistance and type 2 diabetes mellitus. Similar mechanisms can also operate in adipose tissue and heart muscle. In contrast, mitochondrial oxidative capacity is transiently upregulated in the liver of obese insulin-resistant humans with or without fatty liver, giving rise to oxidative stress and declines in advanced fatty liver disease. These data suggest a highly tissue-specific interaction between insulin sensitivity and oxidative metabolism during the course of metabolic diseases in humans. PMID:27146012

  14. Phosphate availability alters architecture and causes changes in hormone sensitivity in the Arabidopsis root system.

    Science.gov (United States)

    López-Bucio, José; Hernández-Abreu, Esmeralda; Sánchez-Calderón, Lenin; Nieto-Jacobo, María Fernanda; Simpson, June; Herrera-Estrella, Luis

    2002-05-01

    The postembryonic developmental program of the plant root system is plastic and allows changes in root architecture to adapt to environmental conditions such as water and nutrient availability. Among essential nutrients, phosphorus (P) often limits plant productivity because of its low mobility in soil. Therefore, the architecture of the root system may determine the capacity of the plant to acquire this nutrient. We studied the effect of P availability on the development of the root system in Arabidopsis. We found that at P-limiting conditions (increase in auxin sensitivity in the roots of P-deprived Arabidopsis seedlings. It was also found that the axr1-3, axr2-1, and axr4-1 Arabidopsis mutants have normal responses to low P availability conditions, whereas the iaa28-1 mutant shows resistance to the stimulatory effects of low P on root hair and lateral root formation. Analysis of ethylene signaling mutants and treatments with 1-aminocyclopropane-1-carboxylic acid showed that ethylene does not promote lateral root formation under P deprivation. These results suggest that in Arabidopsis, auxin sensitivity may play a fundamental role in the modifications of root architecture by P availability. PMID:12011355

  15. GAMMA RADIATION INTERACTS WITH MELANIN TO ALTER ITS OXIDATION-REDUCTION POTENTIAL AND RESULTS IN ELECTRIC CURRENT PRODUCTION

    Energy Technology Data Exchange (ETDEWEB)

    Turick, C.; Ekechukwu, A.; Milliken, C.

    2011-05-17

    The presence of melanin pigments in organisms is implicated in radioprotection and in some cases, enhanced growth in the presence of high levels of ionizing radiation. An understanding of this phenomenon will be useful in the design of radioprotective materials. However, the protective mechanism of microbial melanin in ionizing radiation fields has not yet been elucidated. Here we demonstrate through the electrochemical techniques of chronoamperometry, chronopotentiometry and cyclic voltammetry that microbial melanin is continuously oxidized in the presence of gamma radiation. Our findings establish that ionizing radiation interacts with melanin to alter its oxidation-reduction potential. Sustained oxidation resulted in electric current production and was most pronounced in the presence of a reductant, which extended the redox cycling capacity of melanin. This work is the first to establish that gamma radiation alters the oxidation-reduction behavior of melanin, resulting in electric current production. The significance of the work is that it provides the first step in understanding the initial interactions between melanin and ionizing radiation taking place and offers some insight for production of biomimetic radioprotective materials.

  16. The WST survival assay: An easy and reliable method to screen radiation-sensitive individuals

    International Nuclear Information System (INIS)

    An easy, fast and reliable method was developed to screen hundreds of Epstein-Barr virus-transformed cell lines (lymphoblastoid cell lines, LCLs) for radiation sensitivity that were generated from lymphocytes isolated from young lung cancer patients. The WST-1 test explores the metabolic activity of the mitochondria as an indicator for the vital status of cells. Cell proliferation as well as indirect cell death can be quantified by this method on a large scale in microtiter plates. Cell survival was measured at 24- and 48-h post-irradiation with 10 Gy (137Cs source) by the WST-1 assay and Trypan blue staining. To set up the experimental screening conditions and to establish a positive and a negative control, an ATM-mutated cell line from a radiation-sensitive ATM patient and an ATM proficient cell line from a healthy brother were compared. An optimal differentiation between the two cell lines was demonstrated for 10 Gy and 24- and 48-h cell growth after irradiation. Upon screening 120 LCLs of young lung cancer patients under these conditions, 5 of them were found to be radiation sensitive to a high degree of statistical significance. The results have been confirmed by a second laboratory by means of Trypan blue testing. The WST-1 test represents an efficient and reliable method by means of screening for radiation-sensitive cell lines. (authors)

  17. Differential sensitivity to natural ultraviolet radiation among phytoplankton species in Arctic lakes (Spitsbergen, Norway)

    NARCIS (Netherlands)

    Donk, van E.; Faafeng, B.A.; Lange, de H.J.

    2001-01-01

    Incubation experiments demonstrated a differential sensitivity to natural UV-radiation among the dominant phytoplankton species from three Arctic lakes, situated near Ny-Ålesund, Spitsbergen (79° N). The growth of small chlorophytes, diatoms and picocyanobacteria from two oligotrophic lakes was inhi

  18. Differential sensitivity to natural ultraviolet radiation among phytoplankton species in Arctic lakes (Spitsbergen, Norway)

    NARCIS (Netherlands)

    Van Donk, E.; Faafeng, B.A.; De Lange, H.J.; Hessen, D.O.

    2001-01-01

    Incubation experiments demonstrated a differential sensitivity to natural UV-radiation among the dominant phytoplankton species from three Arctic lakes, situated near Ny-Angstrom lesund, Spitsbergen (79 degrees N). The growth of small chlorophytes, diatoms and picocyanobacteria from two oligotrophic

  19. Sensitization to therapy by hyperthermia and radiation. In order to enhance apoptosis

    Energy Technology Data Exchange (ETDEWEB)

    Ohta, Ichiro; Takahashi, Akihisa; Ohnishi, Ken; Ohnishi, Takeo [Nara Medical Univ., Kashihara (Japan)

    2000-03-01

    Recent findings and authors' investigations are described in this review on sensitization of hyperthermic and radiation therapies for the purpose to enhance apoptosis of cancer cells. Factors concerning the sensitization include cell cycle, repair of radiation-induced DNA damage, recovery of heat-denatured protein and p53 genotype which authors have mainly concerned. Authors found out that apoptosis was inducible by heat and radiation only in cells possessing normal p53 gene. Since cancer cells are generally in the state resistant to apoptosis, elucidation of the mechanism of apoptosis induced by radiation and temperature is important. Factors enhancing the apoptosis in those cells are recombination of normal p53 gene, chemical chaperons, NaCl and heavy particle irradiation. As for a chaperon, treatment of human glioblastoma cells possessing mutated p53 gene with glycerol was found to result in enhancement of apoptosis. Killing effect of carbon beam on cells was higher than that of X-ray regardless to p53 genotype. As above, authors have revealed the importance of p53 in sensitization of cancer cells to heat- and radiation-induced apoptosis. (K.H.)

  20. The effect of post-mastectomy radiation therapy on breast implants: Unveiling biomaterial alterations with potential implications on capsular contracture

    International Nuclear Information System (INIS)

    Post-mastectomy breast reconstruction with expanders and implants is recognized as an integral part of breast cancer treatment. Its main complication is represented by capsular contracture, which leads to poor expansion, breast deformation, and pain, often requiring additional surgery. In such a scenario, the debate continues as to whether the second stage of breast reconstruction should be performed before or after post-mastectomy radiation therapy, in light of potential alterations induced by irradiation to silicone biomaterial. This work provides a novel, multi-technique approach to unveil the role of radiotherapy in biomaterial alterations, with potential involvement in capsular contracture. Following irradiation, implant shells underwent mechanical, chemical, and microstructural evaluation by means of tensile testing, Attenuated Total Reflectance Fourier Transform InfraRed spectroscopy (ATR/FTIR), Scanning Electron Microscopy (SEM), high resolution stylus profilometry, and Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS). Our findings are consistent with radiation-induced modifications of silicone that, although not detectable at the microscale, can be evidenced by more sophisticated nanoscale surface analyses. In light of these results, biomaterial irradiation cannot be ruled out as one of the possible co-factors underlying capsular contracture. - Highlights: • The debate continues whether to perform breast reconstruction before or after PMRT. • Radiation therapy may alter implant material, concurring to capsular contracture. • In this work, irradiated implants were investigated by a multi-technique approach. • Radiation-induced alterations could be evidenced by ATR/FTIR and ToF-SIMS. • Reported alteration might represent a co-factor underlying capsular contracture

  1. The effect of post-mastectomy radiation therapy on breast implants: Unveiling biomaterial alterations with potential implications on capsular contracture

    Energy Technology Data Exchange (ETDEWEB)

    Ribuffo, Diego; Lo Torto, Federico [Department of Plastic Surgery, “Sapienza” University of Rome, Viale del Policlinico 155, 00166 Rome (Italy); Giannitelli, Sara M. [Tissue Engineering Unit, Department of Engineering, Università Campus Bio-Medico di Roma, Via Álvaro del Portillo 21, 00128 Rome (Italy); Urbini, Marco; Tortora, Luca [Surface Analysis Laboratory, Department of Mathematics and Physics, University “Roma Tre”, Via della Vasca Navale 84, 00146 Rome (Italy); INFN — National Institute of Nuclear Physics, Section of Roma Tre, Via della Vasca Navale 84, 00146 Rome (Italy); Mozetic, Pamela; Trombetta, Marcella [Tissue Engineering Unit, Department of Engineering, Università Campus Bio-Medico di Roma, Via Álvaro del Portillo 21, 00128 Rome (Italy); Basoli, Francesco; Licoccia, Silvia [Department of Chemical Science and Technologies, University of Rome “Tor Vergata”, Via della Ricerca Scientifica 1, 00173 Rome (Italy); Tombolini, Vincenzo [Department of Radiation Oncology, “Sapienza” University of Rome, Viale del Policlinico 155, 00166 Rome (Italy); Spencer-Lorillard Foundation, Viale Regina Elena 291, 00161 Rome (Italy); Cassese, Raffaele [Department of Radiation Oncology, “Sapienza” University of Rome, Viale del Policlinico 155, 00166 Rome (Italy); Scuderi, Nicolò [Department of Plastic Surgery, “Sapienza” University of Rome, Viale del Policlinico 155, 00166 Rome (Italy); and others

    2015-12-01

    Post-mastectomy breast reconstruction with expanders and implants is recognized as an integral part of breast cancer treatment. Its main complication is represented by capsular contracture, which leads to poor expansion, breast deformation, and pain, often requiring additional surgery. In such a scenario, the debate continues as to whether the second stage of breast reconstruction should be performed before or after post-mastectomy radiation therapy, in light of potential alterations induced by irradiation to silicone biomaterial. This work provides a novel, multi-technique approach to unveil the role of radiotherapy in biomaterial alterations, with potential involvement in capsular contracture. Following irradiation, implant shells underwent mechanical, chemical, and microstructural evaluation by means of tensile testing, Attenuated Total Reflectance Fourier Transform InfraRed spectroscopy (ATR/FTIR), Scanning Electron Microscopy (SEM), high resolution stylus profilometry, and Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS). Our findings are consistent with radiation-induced modifications of silicone that, although not detectable at the microscale, can be evidenced by more sophisticated nanoscale surface analyses. In light of these results, biomaterial irradiation cannot be ruled out as one of the possible co-factors underlying capsular contracture. - Highlights: • The debate continues whether to perform breast reconstruction before or after PMRT. • Radiation therapy may alter implant material, concurring to capsular contracture. • In this work, irradiated implants were investigated by a multi-technique approach. • Radiation-induced alterations could be evidenced by ATR/FTIR and ToF-SIMS. • Reported alteration might represent a co-factor underlying capsular contracture.

  2. Mesenchymal stem cells are sensitive to treatment with kinase inhibitors and ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Nicolay, Nils H.; Debus, Juergen; Huber, Peter E. [Heidelberg University Hospital, Department of Radiation Oncology, Heidelberg (Germany); German Cancer Research Center (dkfz), Department of Molecular and Radiation Oncology, Heidelberg (Germany); Sommer, Eva; Lopez Perez, Ramon; Wirkner, Ute [German Cancer Research Center (dkfz), Department of Molecular and Radiation Oncology, Heidelberg (Germany); Bostel, Tilman [Heidelberg University Hospital, Department of Radiation Oncology, Heidelberg (Germany); Ho, Anthony D.; Saffrich, Rainer [Heidelberg University Hospital, Department of Hematology, Oncology and Rheumatology, Heidelberg (Germany); Lahn, Michael [Lilly Research Laboratories, Oncology Early Clinical Investigation, Indianapolis, IN (United States)

    2014-11-15

    Mesenchymal stem cells (MSCs) can regenerate damaged tissues and may therefore be of importance for normal tissue repair after cancer treatment. Small molecule receptor kinase inhibitors (RKIs) have recently been introduced into cancer treatment. However, the influence of these drugs - particularly in combination with radiotherapy - on the survival of MSCs is largely unknown. The sensitivity of human primary MSCs from healthy volunteers and primary human fibroblast cells to small molecule kinase inhibitors of the vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF) and transforming growth factor β (TGFβ) receptors, as well to inhibitors of c-Kit, was examined in combination with ionizing radiation (IR); cell survival and proliferation were assessed. Expression patterns of different kinase receptors and ligands were investigated using gene arrays. MSCs were highly sensitive to the tyrosine kinase inhibitors SU14816 (imatinib) and SU11657 (sunitinib), but showed only moderate sensitivity to the selective TGFβ receptor 1 inhibitor LY2109761. Primary adult human fibroblasts were comparably resistant to all three inhibitors. The addition of IR had an additive or supra-additive effect in the MSCs, but this was not the case for differentiated fibroblasts. Proliferation was markedly reduced in MSCs following kinase inhibition, both with and without IR. Gene expression analysis revealed high levels of the PDGF α and β receptors, and lower levels of the TGFβ receptor 2 and Abl kinase. IR did not alter the expression of kinase receptors or their respective ligands in either MSCs or adult fibroblasts. These data show that MSCs are highly sensitive to RKIs and combination treatments incorporating IR. Expression analyses suggest that high levels of PDGF receptors may contribute to this effect. (orig.) [German] Mesenchymale Stammzellen (MSCs) koennen die Geweberegeneration unterstuetzen und haben daher moeglicherweise eine Rolle bei der Reparatur

  3. The potential sensitivity of tropical plants to increased ultraviolet-B radiation

    International Nuclear Information System (INIS)

    Little is known concerning the impact of stratospheric ozone depletion and increasing ultraviolet (UV)-B radiation on the phenology and growth of tropical plants. This is because, ostensibly, tropical plants are already exposed to relatively high levels of UV-B radiation (relative to a temperate environment) and should, therefore, possess a greater degree of tolerance to increased UV-B radiation. In this brief review I hope to show that, potentially, direct and indirect effects on photosynthesis, assimilate partitioning, phenology and biomass could occur in both tropical crops (e.g. cassava, rice) and native species (e.g. Cecropia obtusifolia (Bertol. Fl)., Tetramolopium humile (Gray), Nana sandwicensis L.). However, it should be noted that differences in sensitivity to UV-B radiation can be related to experimental conditions, and care should be taken to ensure that the quantity and quality of background solar radiation remains at near ambient conditions. Nevertheless, by integrating current and past studies on the impact of UV-B radiation on tropical species, I hope to be able to demonstrate that photosynthesis, morphology and growth in tropical plants could be directly affected by UV-B radiation and that UV-B radiation may be a factor in species and community dynamics in natural plant populations in the tropics

  4. Sensitivity to UV radiation in early life stages of the Mediterranean sea urchin Sphaerechinus granularis (Lamarck)

    Energy Technology Data Exchange (ETDEWEB)

    Nahon, Sarah [UPMC Univ Paris 06, UMR 7621, LOBB, Observatoire Oceanologique, F-66651, Banyuls/mer (France); CNRS, UMR 7621, LOBB, Observatoire Oceanologique, F-66651, Banyuls/mer (France); Castro Porras, Viviana A. [UPMC Univ Paris 06, UMR 7621, LOBB, Observatoire Oceanologique, F-66651, Banyuls/mer (France); Pruski, Audrey M. [UPMC Univ Paris 06, UMR 7621, LOBB, Observatoire Oceanologique, F-66651, Banyuls/mer (France); CNRS, UMR 7621, LOBB, Observatoire Oceanologique, F-66651, Banyuls/mer (France); Charles, Francois [UPMC Univ Paris 06, UMR 7621, LOBB, Observatoire Oceanologique, F-66651, Banyuls/mer (France); CNRS, UMR 7621, LOBB, Observatoire Oceanologique, F-66651, Banyuls/mer (France)], E-mail: charles@obs-banyuls.fr

    2009-03-01

    The sea urchin Sphaerechinus granularis was used to investigate the impact of relevant levels of UV-B radiation on the early life stages of a common Mediterranean free spawning benthic species. Sperm, eggs and embryos were exposed to a range of UV radiation doses. The resulting endpoints were evaluated in terms of fertilisation success, development and survival rates. Above a weighted UV radiation dose of 0.0029 kJ m{sup -2}, fertilisation capability of irradiated sperm decreased rapidly. The exposure of the eggs to 0.0175 kJ m{sup -2} and more led to delayed and inhibited development with ensuing embryonic morphological abnormalities. One-day old larvae remained strongly sensitive to UV radiation as shown by the 50% decrease of the larval survival rate for a dose of 0.025 kJ m{sup -2} UVR. The elevated sensitivity of embryos to experimental UVR went along with a lack of significant amount of sunscreen compounds (e.g., mycosporine-like amino acids) in the eggs. The present results demonstrated that gamete viability and embryonic development may be significantly impaired by solar UV radiation in S. granularis, compromising in this way the reproduction of the species. Unless adaptive behavioural reproductive strategies exist, the influence of ambient UV radiation appears as a selective force for population dynamics of broadcast spawners in the shallow benthic Mediterranean environment.

  5. Radiation-induced increases in sensitivity of cataleptic behavior to haloperidol: possible involvement of prostaglandins

    International Nuclear Information System (INIS)

    The effects of radiation exposure on haloperidol-induced catalepsy were examined in order to determine whether elevated prostaglandins, through an action on dopaminergic autoreceptors, could be involved in the radiation-induced increase in the potency of this neuroleptic. Cataleptic behavior was examined in animals irradiated with various doses of gamma photons (1-150 Gy) and pretreated with a subthreshold dose of haloperidol (0.1 mg/kg). This approach was chosen to maximize any synergistic effects of radiation and haloperidol. After irradiation with doses less than or equal to 30 Gy, the combined treatment of haloperidol and radiation produced catalepsy, whereas neither treatment alone had an effect. This observed catalepsy could be blocked with prior administration of indomethacin, a prostaglandin synthesis inhibitor. Animals exposed to doses of radiation less than or equal to 50 Gy and no haloperidol, however, displayed apparent catalepsy. This effect was also antagonized by indomethacin. Prostaglandins can induce catalepsy and when administered in subthreshold doses along with subthreshold doses of haloperidol, catalepsy was observed. In order to assess a possible action of prostaglandins and radiation on dopaminergic activity, the functioning of striatal dopaminergic autoreceptors was examined by determining the effects of varying concentrations of haloperidol on the K+-evoked release of dopamine from striatal slices obtained from parallel groups of animals treated as above. Results indicated that sensitivity to haloperidol increased (higher K+-evoked dopamine release) in slices from irradiated or prostaglandin-treated animals and that this increase in sensitivity was blocked by indomethacin

  6. p53-Mediated apoptosis is the primary cause of radiation sensitivity in ataxia-telangiectasia

    International Nuclear Information System (INIS)

    The autosomal recessive disease ataxia-telangiectasia (A-T) is characterized by ataxia, immune defects, genetic instability and cancer. A cardinal feature of A-T is a marked sensitivity to the killing effects of ionizing radiation. However, repair of DNA damage in A-T cells is grossly normal and the cause of the radiation sensitivity has remained puzzling despite numerous investigations. We now report that p53-mediated apoptosis is primarily responsible for the radiation sensitivity of A-T cells. We exposed representing three different complementation groups as well as two control cell lines to 0, 1.5 and 3 Gy of 250 kv X-radiation. Morphologic changes, the appearance of cells with sub-G1 DNA content and presence of nucleosome ladders in genomic DNA were considered evidence of apoptosis. By all three criteria, apoptosis was detectable in the A-T cells 24-48 hours after irradiation, peaking by 72 hours. In contrast, control cells underwent minimal apoptosis. Similar results were obtained with 24 hours' exposure to 0.25-0.5 ng/ml streptonigrin, a radiomimetic mutagen. Disruption of p53 function in an A-T fibroblast line by transfection of either the dominant-negative p53143ala mutant or an HPV18 E6 gene was associated with acquisition of near-normal drug resistance and radiation-resistance, while transfection and expression of the p53143ala mutant did not affect the streptonigrin sensitivity of a control fibroblast line. Our results support our hypothesis that an unusually low threshold for the activation of p53-mediated apoptosis by DNA damage may be the primary etiology for both in vivo and in vitro mutagen-sensitivity in A-T. These data also suggest an etiology for the neurological deterioration and immune defects seen in A-T patients: inappropriate activation of apoptosis by spontaneous DNA damage

  7. Studies on the Photoperiod Sensitive Characters of Male Fertility Alteration of Peiai64S' Main Male Genic Sterile Gene

    Institute of Scientific and Technical Information of China (English)

    ZENG Han-lai; ZHANG Duan-pin; ZHANG Zhi-yu; YI Wen-kai; ZHU Xin; MENG Hui-jun

    2002-01-01

    Peiai64S, an indica male sterile rice with a male fertility alteration under different environments, is selected from the offspring of indica rice crossed with Nongken58S. Nongken58S, a japonica photoperiod sensitive genic male sterile rice (PGMS), deriving from a natural mutant plant individual of normal japonica rice variety, Nongken58, is used as a male sterile gene donor of Peiai64S. But Peiai64S is not a typical PGMS rice, the male fertility is sensitive to temperature just as thermo-sensitive genic male sterile rice (TGMS). We have selected typical PGMS plants in F2 population of Peiai64S × Nongken58, whose ratio of fertile plants to sterile plants is nearly 3:1. The sterility inheritance conformed to one pair of gene segregation model. The result indicates the main male sterile gene in Peiai64S is not other than the PGMS gene, and comes from Nongken58S. The genetic background affects effective expression of the PGMS gene. This suggests that we ought to focus on optimizing the genetic background of the PGMS gene in PGMS rice breeding, and select an ideal genetic background as a transgenic background in molecular breeding.

  8. Alteration of the digestive motility linked with radiation-induced inflammatory processes in rats; Alterations de la motricite digestive associees aux processus inflammatoires induits par les rayonnements ionisants chez le rat

    Energy Technology Data Exchange (ETDEWEB)

    Picard, C

    2000-12-01

    Exposure to ionizing radiation, whether accidental or for medical reasons, may lead to gastro-intestinal injury, characterized by nausea, vomiting, diarrhea and abdominal cramps. The aetiology of radiation-induced diarrhea remains to date unclear. In this study, we have investigated the acute effects of a 10 Gy abdominal irradiation on rat digestive functions. The objective of the first study was to evaluate the role of sensory afferent neurons, capsaicin-sensitive, on morphological changes and the inflammatory response following exposure. Three days after irradiation, we observed an inflammatory response characterized by neutrophils infiltration and mast cells de-granulation. No effect of capsaicin pre-treatment was seen on these parameters. However, neutrophils infiltration was increased as early as one day after irradiation in capsaicin-treated rats. No difference in severity of diarrhea was observed after denervation nor in morphological changes. These data demonstrate that abdominal irradiation results in diarrhea concomitant with an inflammatory response, and that sensory innervation does not play a major protective role. The objective of the rest of the work was in the first instance to characterize radiation-induced alterations of intestinal and colonic motility leading to diarrhea and secondly to evaluate the role of serotonin in such disorders. Perturbations in intestinal (MMC) and colonic (LSB) motor profiles were observed from the first day onwards. Migrating motor complexes (MMC) were completely disrupted at three days at the same time as the onset of diarrhea. In addition to inhibition of LSB, colonic fluid absorptive capacity was decreased and serotonin colonic tissue levels were increased three days after irradiation. Radiation-induced diarrhea was reduced by treatment with an antagonist of 5-HT{sub 3} receptors, granisetron, as were alterations of colonic motility and serotonin tissue levels. However, this treatment did not significantly ameliorate

  9. Acquisition of anoikis resistance in human osteosarcoma cells does not alter sensitivity to chemotherapeutic agents

    Directory of Open Access Journals (Sweden)

    McIntyre Bradley W

    2005-04-01

    Full Text Available Abstract Background Chemotherapy-induced cell death can involve the induction of apoptosis. Thus, aberrant function of the pathways involved might result in chemoresistance. Since cell adhesion to the extracellular matrix acts as a survival factor that homeostatically maintains normal tissue architecture, it was tested whether acquisition of resistance to deadhesion-induced apoptosis (anoikis in human osteosarcoma would result in resistance to chemotherapy. Methods Osteosarcoma cell lines (SAOS-2 and TE-85 obtained from ATCC and were maintained in complete Eagle's MEM medium. Suspension culture was established by placing cells in tissue culture wells coated with poly-HEMA. Cell cytotoxicity was determined using a live/dead cytotoxicity assay. Cell cycle/apoptosis analyses were performed using propidium iodide (PI staining with subsequent FACS analysis. Apoptosis was also assayed by Annexin-FITC/PI staining. Results Etoposide, adriamycin, vinblastine, cisplatin and paclitaxel were able to induce apoptosis in human osteosarcoma cells SAOS-2 regardless of their anoikis resistance phenotype or the culture conditions (adhered vs. suspended. Moreover, suspended anoikis resistant TE-85 cells (TE-85ar retained their sensitivity to chemotherapy as well. Conclusion Acquisition of anoikis resistance in human osteosarcoma cells does not result in a generalized resistance to all apoptotic stimuli, including chemotherapy. Moreover, our results suggest that the pathways regulating anoikis resistance and chemotherapy resistance might involve the action of different mediators.

  10. High temperature, drought and their interaction induced protein alterations in sensitive and tolerant wheat varieties

    Directory of Open Access Journals (Sweden)

    Vikender Kaur, Reena Mahla And R.K.Behl

    2014-12-01

    Full Text Available Two contrasting wheat (Triticum aestivum L. cultivars WH730 (high temperature tolerant and UP2565 (high temperature sensitive were tested for differential response to combined and individually applied high temperature (HT and drought (D stress at seedling stage for peptide profile. Initial profile of the stress induced peptides was outlined via SDS electrophoresis of leaf extracts. Electrophoretic pattern of proteins revealed expression of new bands as well as disappearance of certain others in HT, D and interactive HT+D stress treated and revived samples in both wheat varieties relative to untreated control samples. Some of the bands that appeared in stress treated seedlings were also present after revival indicating their protective role, while some new peptides synthesized after stress but disappeared after revival period may be designated true stress proteins. However, all the plants from heat, drought and their interactive stress treatments continued to grow during recovery period. This suggests that these proteins and other newly synthesized proteins may have protective effects at high temperature (40°C and water scarcity and provide plants for healthy growth during the recovery period. Furthermore, elucidating the functions of proteins expressed by genes in stress tolerant and susceptible plants may provide important information for designing new strategies for crop improvement.

  11. Correction method for β-ray sensitivity of two dimensional radiation detector and planar radiation source to be used for the method, and correction device for β-ray sensitivity of two dimensional radiation detector

    International Nuclear Information System (INIS)

    The present invention provides a method of correcting β-ray sensitivity of a two dimensional radiation detector, a planar radiation source to be used for the method and a correction device for β-ray sensitivity of the two dimensional radiation detector. Namely, a planar radiation source on which Pm-147 is coated at a thickness greater than an infinite thickness is brought into intimate contact with or made close to an imaging plate (IP). Then, a phosphorescent intensity (PSL) value at each portion of IP is measured. A ratio of the measured value at each portion relative to the average value is determined as a correction coefficient for β-ray sensitivity. The β-ray sensitivity coefficient is multiplied to the PSL value measured at each of the portions to obtain a true PSL when IP is used subsequently. In this case, Pm-147 is used as the radiation source since it is noted that Pm-147 has an energy distribution approximate to the β-ray energy of C-14 as radioactive isotopes most frequently used, and its half fine is 2.623 years. Namely, the disintegration constant of Pm-147 is 2180 times the disintegration constant of C-14, and it has an extremely high β-ray density. (I.S.)

  12. Altered ratio of D1 and D2 dopamine receptors in mouse striatum is associated with behavioral sensitization to cocaine.

    Directory of Open Access Journals (Sweden)

    Dawn Thompson

    Full Text Available BACKGROUND: Drugs of abuse elevate brain dopamine levels, and, in vivo, chronic drug use is accompanied by a selective decrease in dopamine D2 receptor (D2R availability in the brain. Such a decrease consequently alters the ratio of D1R:D2R signaling towards the D1R. Despite a plethora of behavioral studies dedicated to the understanding of the role of dopamine in addiction, a molecular mechanism responsible for the downregulation of the D2R, in vivo, in response to chronic drug use has yet to be identified. METHODS AND FINDINGS: ETHICS STATEMENT: All animal work was approved by the Gallo Center IACUC committee and was performed in our AAALAC approved facility. In this study, we used wild type (WT and G protein coupled receptor associated sorting protein-1 (GASP-1 knock out (KO mice to assess molecular changes that accompany cocaine sensitization. Here, we show that downregulation of D2Rs or upregulation of D1Rs is associated with a sensitized locomotor response to an acute injection of cocaine. Furthermore, we demonstrate that disruption of GASP-1, that targets D2Rs for degradation after endocytosis, prevents cocaine-induced downregulation of D2Rs. As a consequence, mice with a GASP-1 disruption show a reduction in the sensitized locomotor response to cocaine. CONCLUSIONS: Together, our data suggests that changes in the ratio of the D1:D2R could contribute to cocaine-induced behavioral plasticity and demonstrates a role of GASP-1 in regulating both the levels of the D2R and cocaine sensitization.

  13. Electron beam radiation induced oxidative stress on alteration of enzymatic antioxidant status of Swiss albino mice

    International Nuclear Information System (INIS)

    Ionizing radiation causes damage to living tissues through a series of molecular events, such as photoelectric, Compton and Auger effects, depending on the radiation energy. Because human tissues contain 80% water, the major radiation damage is due to the aqueous free radicals, generated by the action of radiation on water. It was found to be 10 Gy was the lethal dose for mice. Different dosages (4 Gy, 6 Gy and 8 Gy) of electron beam radiation were used to study the level of lipid peroxidation and enzymatic antioxidant status of irradiated mice. The results showed higher the radiation dosage, increased lipid peroxidation and decreased antioxidant level. (author)

  14. Multiparametric assessment of radiation effects for the individual radiation sensitivity estimation; Multiparametrische Erfassung von Strahlenwirkungen zur Abschaetzung der individuellen Strahlenempfindlichkeit

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    The effects of low dose irradiation are highly relevant for radiation protection in the public. The sensitivity to clastogenic and tumorigenic effects of ionizing radiation (IR) varies considerably amongst individuals. Examples for genetically determined enhanced sensitivity are well known in some hereditary diseases: patients with chromosomal instability syndromes, Ataxia telangiectasia (A-T), Nijmegen Breakage Syndrome (NBS) and Bloom Syndrome (BS) show strongly enhanced sensitivity towards IR, severe immunodeficiencies, and a high incidence for developing leukemias and lymphomas. This obvious coincidence of enhanced radiosensitivity and tumor risk, and the frequently observed enhanced radiosensitivity of genetically non-defined tumor patients indicate that tumor patients may constitute a subpopulation with enriched genetical predisposition for enhanced radiosensitivity. Furthermore, a subpopulation of radiosensitive individuals may be part of the probably inconspicuous total population. For example, individuals heterozygous for the above mentioned genes (and possibly some other genes) show enhanced radiosensitivity if compared with the normal population. In general, heterozygous carriers of those hereditary deficiencies are clinically inconspicuous, but due an haploinsufficiency their tumour risk may be enhanced. This has been shown for mice carrying an heterozygous Nbs1 mutation (J.-Q. Wang, Lyon, pers. Communication). Our findings concerning enhanced radiation-induced chromosomal aberrations in heterozygous Nbs1 cell lines support this notion. The identification of high risk groups with enhanced radiosensitivity is therefore an important task for radioprotection. This project aimed at establishing a procedure which allows to test various cellular parameters as indicators for effects of radiation. A standard protocol for the isolation and cryoconservation of primary blood cells was developed. DNA repair analysis (Comet Assay) and radiation-induced apoptosis

  15. Sensitizers for the Radiation-Induced Vulcanization of Natural Rubber and Other Hydrocarbon Polymers

    International Nuclear Information System (INIS)

    A considerable volume of work has been directed towards the radiation-induced vulcanization of natural and synthetic rubbers, principally with a view to finding a novel application of radiation in the processing and manufacture of rubber products. It is clear that the cost of such processing is high and the mechanical properties of the radiation-vulcanized product are inferior when compared to its sulphur-cured competitor; only in a limited number of properties, e.g. heat aging, is there any improvement. The present work describes a laboratory study of sensitizers which enable the dose for a satisfactory cure to be reduced from 40-50 Mrad to 2-5 Mrad or even lower doses if conditions are carefully controlled. The mechanism of the reaction is described and it is shown that as the radiation-induced cross-linking reaction in the presence of these sensitizers is a chain process, the reaction becomes dose rate dependent and, therefore, it is favoured by the use of isotope sources giving a low dose rate. The physical properties of the cross-linked rubbers are compared with those made by peroxide and sulphur-curing techniques and the differences are explained in terms of the nature of the new type of cross link. Isotope-labelled sensitizers have been used to determine independently the concentration of cross-links produced by irradiation. (author)

  16. A novel high-throughput irradiator for in vitro radiation sensitivity bioassays

    Science.gov (United States)

    Fowler, Tyler L.

    Given the emphasis on more personalized radiation therapy there is an ongoing and compelling need to develop high-throughput screening tools to further examine the biological effects of ionizing radiation on cells, tissues and organ systems in either the research or clinical setting. Conventional x-ray irradiators are designed to provide maximum versatility to radiobiology researchers, typically accommodating small animals, tissue or blood samples, and cellular applications. This added versatility often impedes the overall sensitivity and specificity of an experiment resulting in a trade-off between the number of absorbed doses (or dose rates) and biological endpoints that can be investigated in vitro in a reasonable amount of time. Therefore, modern irradiator designs are incompatible with current high-throughput bioassay technologies. Furthermore, important dosimetry and calibration characteristics (i.e. dose build-up region, beam attenuation, and beam scatter) of these irradiators are typically unknown to the end user, which can lead to significant deviation between delivered dose and intended dose to cells that adversely impact experimental results. Therefore, the overarching goal of this research is to design and develop a robust and fully automated high-throughput irradiator for in vitro radiation sensitivity investigations. Additionally, in vitro biological validation of this system was performed by assessing intracellular reactive oxygen species production, physical DNA double strand breaks, and activation of cellular DNA repair mechanisms. Finally, the high-throughput irradiator was used to investigate autophagic flux, a cellular adaptive response, as a potential biomarker of radiation sensitivity.

  17. Helicity sensitive terahertz radiation detection by dual-grating-gate high electron mobility transistors

    International Nuclear Information System (INIS)

    We report on the observation of a radiation helicity sensitive photocurrent excited by terahertz (THz) radiation in dual-grating-gate (DGG) InAlAs/InGaAs/InAlAs/InP high electron mobility transistors (HEMT). For a circular polarization, the current measured between source and drain contacts changes its sign with the inversion of the radiation helicity. For elliptically polarized radiation, the total current is described by superposition of the Stokes parameters with different weights. Moreover, by variation of gate voltages applied to individual gratings, the photocurrent can be defined either by the Stokes parameter defining the radiation helicity or those for linear polarization. We show that artificial non-centrosymmetric microperiodic structures with a two-dimensional electron system excited by THz radiation exhibit a dc photocurrent caused by the combined action of a spatially periodic in-plane potential and spatially modulated light. The results provide a proof of principle for the application of DGG HEMT for all-electric detection of the radiation's polarization state

  18. Helicity sensitive terahertz radiation detection by dual-grating-gate high electron mobility transistors

    Energy Technology Data Exchange (ETDEWEB)

    Faltermeier, P.; Olbrich, P.; Probst, W.; Schell, L.; Ganichev, S. D. [Terahertz Center, University of Regensburg, 93040 Regensburg (Germany); Watanabe, T.; Boubanga-Tombet, S. A.; Otsuji, T. [Research Institute of Electrical Communication, Tohoku University, 980-8577 Sendai (Japan)

    2015-08-28

    We report on the observation of a radiation helicity sensitive photocurrent excited by terahertz (THz) radiation in dual-grating-gate (DGG) InAlAs/InGaAs/InAlAs/InP high electron mobility transistors (HEMT). For a circular polarization, the current measured between source and drain contacts changes its sign with the inversion of the radiation helicity. For elliptically polarized radiation, the total current is described by superposition of the Stokes parameters with different weights. Moreover, by variation of gate voltages applied to individual gratings, the photocurrent can be defined either by the Stokes parameter defining the radiation helicity or those for linear polarization. We show that artificial non-centrosymmetric microperiodic structures with a two-dimensional electron system excited by THz radiation exhibit a dc photocurrent caused by the combined action of a spatially periodic in-plane potential and spatially modulated light. The results provide a proof of principle for the application of DGG HEMT for all-electric detection of the radiation's polarization state.

  19. Plant Temperature for Sterile Alteration of a Temperature-Sensitive Genic Male Sterile Rice, Peiai64S

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The forecast of sterile alteration for the temperature-sensitive genic male sterile (TGMS) line in two-line hybrid rice seed production was traditionally based on screen temperature determined by weather station. The article put forward a new approach based on plant temperature, which was more exact and direct than the traditional method. The result of the simulation of the self-seeded setting rate of a widely used TGMS line, Peiai64S, by several temperature parameters and durations, showed that the fertility was directly affected by the plant temperature at a height of 20 cm or the air temperature around it in three days duration. Using the stem temperature of three days at a height of 20 cm as the simulation parameter,the fertility of Peiai64S had the maximum, minimum and optimum temperatures as 22.8, 21.7 and 22.5℃, respectively,whereas 23.2, 21.5 and 21.8℃ when using the air temperature of three days around the height of 20 cm as the parameter.Such temperature indices can be used to conclude the sterile alteration of TGMS for safeguarding seed production of twoline hybrid rice. The article also established a statistic model to conclude plant temperature by water temperatures at inflow and outflow, and air temperature and cloudage from weather station.

  20. Radiation sensitivity and gene expression in Enchytraeus japonensis, a species of earth worm

    International Nuclear Information System (INIS)

    The importance of radiological protection of the environment based on scientific principles is gaining international recognition as environment issues garner more attention. Earthworm (annelids) is a ubiquitous soil invertebrate known to play an important role in the maintenance of the soil ecosystem and thus selected as one of 12 kinds of reference animals and plants by the ICRP. In the present study, radiation sensitivity and gene expression in a recently described terrestrial oligochaete, Enchytraeus japonensis (E. japonensis) were studied. E. japonensis worms were acutely irradiated at increasing doses of gamma radiation, and the number of worms after 30 days of radiation was examined. The dose effectively inhibiting 50% of proliferation was approximately 22 Gy, which was comparable to the dose required to elicit growth inhibition in other earthworm species. In order to seek other biological endpoints for more sensitive and/or quicker assessment of radiation effects, gene expression profiling in E. japonensis was also performed, and poly (ADP-ribose) polymerase I (PARP I) was identified as a radiation-responsive gene. PARP I transcript level increased dose-dependently. (author)

  1. Sensitivity analysis of numerical weather prediction radiative schemes to forecast direct solar radiation over Australia

    Science.gov (United States)

    Mukkavilli, S. K.; Kay, M. J.; Taylor, R.; Prasad, A. A.; Troccoli, A.

    2014-12-01

    The Australian Solar Energy Forecasting System (ASEFS) project requires forecasting timeframes which range from nowcasting to long-term forecasts (minutes to two years). As concentrating solar power (CSP) plant operators are one of the key stakeholders in the national energy market, research and development enhancements for direct normal irradiance (DNI) forecasts is a major subtask. This project involves comparing different radiative scheme codes to improve day ahead DNI forecasts on the national supercomputing infrastructure running mesoscale simulations on NOAA's Weather Research & Forecast (WRF) model. ASEFS also requires aerosol data fusion for improving accurate representation of spatio-temporally variable atmospheric aerosols to reduce DNI bias error in clear sky conditions over southern Queensland & New South Wales where solar power is vulnerable to uncertainities from frequent aerosol radiative events such as bush fires and desert dust. Initial results from thirteen years of Bureau of Meteorology's (BOM) deseasonalised DNI and MODIS NASA-Terra aerosol optical depth (AOD) anomalies demonstrated strong negative correlations in north and southeast Australia along with strong variability in AOD (~0.03-0.05). Radiative transfer schemes, DNI and AOD anomaly correlations will be discussed for the population and transmission grid centric regions where current and planned CSP plants dispatch electricity to capture peak prices in the market. Aerosol and solar irradiance datasets include satellite and ground based assimilations from the national BOM, regional aerosol researchers and agencies. The presentation will provide an overview of this ASEFS project task on WRF and results to date. The overall goal of this ASEFS subtask is to develop a hybrid numerical weather prediction (NWP) and statistical/machine learning multi-model ensemble strategy that meets future operational requirements of CSP plant operators.

  2. Radioprotective effect of garlic extract on some bacterial strains with different radiation sensitivities

    International Nuclear Information System (INIS)

    The radioprotective effect of garlic on four bacterial strains with different degrees of radiation sensitivities was investigated. The presence of garlic led to an increase in d-10 value of Ps. Aeruginosa, S. aureus and S. typhimurium by 160%, 50%, and 30% respectively. The protective efficiency of garlic against radiation was noticed to be proportional to its concentration in a given inoculum size. Garlic extract up to 180 micro liter per 108 inoculum size of B. cereus showed no protective effect. This fact was attributed to the existence of sulphur compounds in the given strain. Higher garlic concentrations appeared to affect the cloning efficiency of a given strain. 4fig., 2tab

  3. Evaluation of a Fabricated Charge Sensitive Amplifier for a Semiconductor Radiation Detector

    International Nuclear Information System (INIS)

    A CSA(Charge Sensitive Amplifier) was designed and fabricated for application in a radiation detection system based on a semiconductor detector such as Si, SiC, CdZnTe and etc.. A fabricated hybrid.type CSA was evaluated by comparison with a commercially available CSA. A comparison was performed by using calculation of ENC (Equivalent Noise Charge) and by using energy resolutions of fabricated radiation detectors based on Si. In energy resolution comparison, a fabricated CSA showed almost the same performance compared with a commercial one. In this study, feasibility of a fabricated CSA was discussed

  4. Identification of sensitive serum microRNA biomarkers for radiation biodosimetry.

    Directory of Open Access Journals (Sweden)

    Naduparambil Korah Jacob

    Full Text Available Exposure to ionizing radiation through environmental, occupational or a nuclear reactor accident such as the recent Fukushima Daiichi incident often results in major consequences to human health. The injury caused by radiation can manifest as acute radiation syndromes within weeks in organs with proliferating cells such as hematopoietic and gastrointestinal systems. Cancers, fibrosis and degenerative diseases are also reported in organs with differentiated cells, months or years later. Studies conducted on atom bomb survivors, nuclear reactor workers and animal models have shown a direct correlation of these effects with the absorbed dose. Physical dosimeters and the available radio-responsive biologics in body fluids, whose responses are rather indirect, have limitations to accurately evaluate the extent of post exposure damage. We have used an amplification-free, hybridization based quantitative assay utilizing the nCounter multiplex platform developed by nanoString Technologies to compare the levels of over 600 miRNAs in serum from mice irradiated at a range of 1 to 12 Gy at 24 and 48 hr time points. Development of a novel normalization strategy using multiple spike-in oligonucleotides allowed accurate measurement of radiation dose and time dependent changes in serum miRNAs. The response of several evolutionarily conserved miRNAs abundant in serum, were found to be robust and sensitive in the dose range relevant for medical triage and in patients who receive total body radiation as preparative regimen for bone marrow transplantation. Notably, miRNA-150, abundant in lymphocytes, exhibited a dose and time dependent decrease in serum, which we propose as a sensitive marker indicative of lymphocyte depletion and bone marrow damage. Our study has identified several markers useful for evaluation of an individual's response by minimally invasive methods, relevant to triage in case of a radiation accident and evaluation of toxicity and response

  5. The sensitivity of convective aggregation to diabatic processes in idealized radiative-convective equilibrium simulations

    Science.gov (United States)

    Holloway, C. E.; Woolnough, S. J.

    2016-03-01

    Idealized explicit convection simulations of the Met Office Unified Model exhibit spontaneous self-aggregation in radiative-convective equilibrium, as seen in other models in previous studies. This self-aggregation is linked to feedbacks between radiation, surface fluxes, and convection, and the organization is intimately related to the evolution of the column water vapor field. Analysis of the budget of the spatial variance of column-integrated frozen moist static energy (MSE), following Wing and Emanuel (2014), reveals that the direct radiative feedback (including significant cloud longwave effects) is dominant in both the initial development of self-aggregation and the maintenance of an aggregated state. A low-level circulation at intermediate stages of aggregation does appear to transport MSE from drier to moister regions, but this circulation is mostly balanced by other advective effects of opposite sign and is forced by horizontal anomalies of convective heating (not radiation). Sensitivity studies with either fixed prescribed radiative cooling, fixed prescribed surface fluxes, or both do not show full self-aggregation from homogeneous initial conditions, though fixed surface fluxes do not disaggregate an initialized aggregated state. A sensitivity study in which rain evaporation is turned off shows more rapid self-aggregation, while a run with this change plus fixed radiative cooling still shows strong self-aggregation, supporting a "moisture-memory" effect found in Muller and Bony (2015). Interestingly, self-aggregation occurs even in simulations with sea surface temperatures (SSTs) of 295 and 290 K, with direct radiative feedbacks dominating the budget of MSE variance, in contrast to results in some previous studies.

  6. NOXA-induced alterations in the Bax/Smac axis enhance sensitivity of ovarian cancer cells to cisplatin.

    Directory of Open Access Journals (Sweden)

    Chao Lin

    Full Text Available Ovarian cancer is the most common cause of death from gynecologic malignancy. Deregulation of p53 and/or p73-associated apoptotic pathways contribute to the platinum-based resistance in ovarian cancer. NOXA, a pro-apoptotic BH3-only protein, is identified as a transcription target of p53 and/or p73. In this study, we found that genetic variants of Bcl-2 proteins exist among cisplatin-sensitive and -resistant ovarian cancer cells, and the responses of NOXA and Bax to cisplatin are regulated mainly by p53. We further evaluated the effect of NOXA on cisplatin. NOXA induced apoptosis and sensitized A2780s and SKOV3 cells to cisplatin in vitro and in vivo. The effects were mediated by elevated Bax expression, enhanced caspase activation, release of Cyt C and Smac into the cytosol. Furthermore, gene silencing of Bax or Smac significantly attenuated NOXA and/or cisplatin-induced apoptosis in chemosensitive A2780s cells, whereas overexpression of Bax or addition of Smac-N7 peptide significantly increased NOXA and/or cisplatin-induced apoptosis in chemoresistant SKOV3 cells. To our knowledge, these data suggest a new mechanism by which NOXA chemosensitized ovarian cancer cells to cisplatin by inducing alterations in the Bax/Smac axis. Taken together, our findings show that NOXA is potentially useful as a chemosensitizer in ovarian cancer therapy.

  7. Sensitivity coefficients for the stochastic estimation of the radiation damage to the reactor pressure vessel

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, C.M.; Hernandez Valle, S. [Centro de Investigaciones Tecnologicas, Nucleares y Ambientales, La Habana (Cuba). E-mail: calvarez@ctn.isctn.edu.cu; svalle@ctn.isctn.edu.cu

    2000-07-01

    The construction of the sensitivity matrix in the case of the vessel radiation damage estimation by Monte Carlo techniques poses new problems related to the uncertainties of the obtained responses. In the case of deterministic calculations, the sensitivity coefficient obtention is a straightforward procedure based on the perturbation formalism through the calculation of the adjoint fluxes. In the paper an alternative procedure implementation based on the differential operator method is described with the modifications needed to the used HEXANN-EVALU code for the response estimations in the VVER-440 pressure vessel. (author)

  8. Sensitivity of pathogenic and free-living Leptospira spp. to UV radiation and mitomycin C

    International Nuclear Information System (INIS)

    The habitats for the two major Leptospira spp. differ. The main habitat of L. biflexa is soil and water, whereas L. interrogans primarily resides in the renal tubules of animals. We investigated whether these two species, along with L. illini (species incertae sedis), differ with respect to their sensitivity to UV radiation. The doses of UV resulting in 37, 10 and 1% survival were determined for representive serovars from each species. L. interrogans serovar pomona was 3.0 to 4.8 times more sensitive to UV than the other Leptospira species under the 37, 10, and 1% survival parameters. In comparison to other bacteria, L. interrogans serovar pomona is among the most sensitive to UV. In a qualitative UV sensitivity assay., L. interrogans serovars were found to be in general more sensitive than L. biflexa serovars. All three species were found to have a photoreactivation DNA repair mechanism. Since organisms that are resistant to UV are often resistant to the DNA cross-linking agent mitomycin C, we tested the relative sensitivity of several Leptospira serovars to this compound. With few exceptions, L. biflexa and L. illini serovars were considerably more resistant to mitomycin C than the L. interrogans serovars. The mitomycin C sensitivity assay could be a useful addition to current characterization tests used to differentiate the Leptospira species

  9. Sensitivity of pathogenic and free-living Leptospira spp. to UV radiation and mitomycin C

    Energy Technology Data Exchange (ETDEWEB)

    Stamm, L.V.; Charon, N.W.

    1988-03-01

    The habitats for the two major Leptospira spp. differ. The main habitat of L. biflexa is soil and water, whereas L. interrogans primarily resides in the renal tubules of animals. We investigated whether these two species, along with L. illini (species incertae sedis), differ with respect to their sensitivity to UV radiation. The doses of UV resulting in 37, 10 and 1% survival were determined for representive serovars from each species. L. interrogans serovar pomona was 3.0 to 4.8 times more sensitive to UV than the other Leptospira species under the 37, 10, and 1% survival parameters. In comparison to other bacteria, L. interrogans serovar pomona is among the most sensitive to UV. In a qualitative UV sensitivity assay., L. interrogans serovars were found to be in general more sensitive than L. biflexa serovars. All three species were found to have a photoreactivation DNA repair mechanism. Since organisms that are resistant to UV are often resistant to the DNA cross-linking agent mitomycin C, we tested the relative sensitivity of several Leptospira serovars to this compound. With few exceptions, L. biflexa and L. illini serovars were considerably more resistant to mitomycin C than the L. interrogans serovars. The mitomycin C sensitivity assay could be a useful addition to current characterization tests used to differentiate the Leptospira species.

  10. Biochemical reasoning for radiation protection and screening methods for radiation sensitivity and potential carcinogenicity

    International Nuclear Information System (INIS)

    Cells of different genetic characteristics respond differently to agents that modify radiation effects. When the modification is a result of chemical repair, reduction of the amount of damage by radical scavenging, production of hypoxia, or any other such mechanism, then the modification of the response will be the same for all types of cells, but not the same when biological or biochemical parameters are involved, because the differences between the cells affect the final outcome, and the genetic traits obviously become affected by chemical modifying agents. Some of these agents directly affect the repair of deoxyribonucleic acid (DNA) by mechanisms not yet understood. Another agent nicotinamide (NA), is directly linked to a repair pathway. Thus, a system that uses NA as a precursor of nicotinamide adenine dinucleotide (NAD)+, and uses NAD+ to produce the polymer polyadenosine diphosphate ribose (PADPR) appears to be an interesting and important factor in the biochemical events that may be linked to improved radioprotection. (author). 36 refs., 5 figs

  11. Crustaceous lichens sensitive monitor of caesium-137 radiation level in terrestrial environment

    Institute of Scientific and Technical Information of China (English)

    Du Chunguang; Zhao Ye; Zhang Jing; Xu Cuihua

    2005-01-01

    The activity of caesium-137 (Bq/kg) in the crustaceous lichens and other samples was determined to prove the feasibility that crustaceous lichens work as a sensitive biology monitor to record the caesium-137 (Bq/kg) radiation levels of terrestrial environment. The measurements were performed with GEM series HPGe (high-purity Germanium) coaxial detector system (ADCAM -100) made by EC & GORTEC Company in USA. It was found that the activity of caesium-137 (Bq/kg) in the crustaceous lichens was one order of magnitude higher than that found in surface soil,and was over three orders of magnitude higher than those found in the familiar biological samples. These results proved that crustaceous lichens may be one of the most sensitive biological monitors about the remote transmission and environmental radiation levels of caesium-137.

  12. Radio sensitivity of rice genotypes to gamma radiations based on seedling traits and physiological indices

    International Nuclear Information System (INIS)

    Three Basmati rice genotypes viz., 00515, 99417 and Super Basmati were examined for varietal differences in radio sensitivity to gamma radiations. Dry healthy seeds were exposed to variable doses of gamma radiations i.e., 150- 400 Gy with 50 Gy intervals. Highly significant differences among the genotypes (p<0.01) for all traits were observed. The differences among radiation treatments were highly significant (p<0.01) for shoot and root length, shoot and root fresh weight, water uptake, chlorophyll contents (a, b), plant height and panicle fertility while non significant differences were observed for germination percentage only. The genotype X dose interactions were non significant for germination percentage, shoot length, root length, shoot fresh weight and plant height indicating stability of performance for characters across different radiation levels. In contrast, chlorophyll (a, b), root fresh weight, water uptake and panicle fertility exhibited significant differences for interactions. Mutagenic treatments shifted mean values towards negative direction for almost all traits but not in a definite pattern. However, water uptake of seeds increased with increasing gamma radiation doses. In general, genotypes displayed variable response towards gamma radiations. (author)

  13. Rapamycin-mediated mTOR inhibition attenuates survivin and sensitizes glioblastoma cells to radiation therapy

    Institute of Scientific and Technical Information of China (English)

    Arunkumar Anandharaj; Senthilkumar Cinghu; Woo-Yoon Park

    2011-01-01

    Survivin, an antiapoptotic protein, is elevated in most malignancies and attributes to radiation resistance in tumors including glioblastoma multiforme. The downregulation of survivin could sensitize glioblastoma ceils to radiation therapy. In this study, we investigated the effect of rapamycin, an inhibitor of mammalian target of rapamycin (mTOR), in attenuating survivin and enhancing the therapeutic efficacy for glioblastoma cells, and elucidated the underlying mechanisms. Here we tested various concentrations of rapamycin (1-8 nM) in combination with radiation dose 4 Gy. Rapamycin effectively modulated the protein kinase B (Akt)/mTOR pathway by inhibiting the phosphorylation of Akt and mTOR proteins, and this inhibition was further enhanced by radiation. The expression level of survivin was decreased in rapamycin pre-treatment glioblastoma ceils followed by radiation; meanwhile, the phosphorylation of H2A histone family member X (H2AX) at serine-139 (γ-H2AX) was increased, p21 protein was also induce on radiation with rapamycin pre-treatment, which enhanced G1 arrest and the accumulation of cells at G0/subG1 phase. Furthermore, the clonogenic cell survival assay revealed a significant dose-dependent decrease in the surviving fraction for all three cell lines pre-treated with rapamycin. Our studies demonstrated that targeting survivin may be an effective approach for radiosensitization of malignant glioblastoma.

  14. Potential sensitivity of photosynthesis and isoprene emission to direct radiative effects of atmospheric aerosol pollution

    OpenAIRE

    Strada, Susanna; Unger, Nadine

    2016-01-01

    A global Earth system model is applied to quantify the impacts of direct anthropogenic aerosol effective radiative forcing on gross primary productivity (GPP) and isoprene emission. The impacts of different pollution aerosol sources (anthropogenic, biomass burning, and non-biomass burning) are investigated by performing sensitivity experiments. The model framework includes all known light and meteorological responses of photosynthesis, but uses fixed canopy structures and ph...

  15. Co-injection strategies to modify radiation sensitivity and tumor initiation in transgenic Zebrafish

    OpenAIRE

    Langenau, DM; Keefe, MD; Storer, NY; Jette, CA; Smith, ACH; Ceol, CJ; Bourque, C; Look, AT; Zon, LI

    2008-01-01

    The zebrafish has emerged as a powerful genetic model of cancer, but has been limited by the use of stable transgenic approaches to induce disease. Here, a co-injection strategy is described that capitalizes on both the numbers of embryos that can be microinjected and the ability of transgenes to segregate together and exert synergistic effects in forming tumors. Using this mosaic transgenic approach, gene pathways involved in tumor initiation and radiation sensitivity have been identified.

  16. The radiation sensitizing effect of PSK in the treatment for the cervical cancer patients

    International Nuclear Information System (INIS)

    PSK is the protein-bound polysaccharide isolated from Coriolus versicolor (strain CM-101) belonging to Basidiomycetes. It has been widely used as antitumor agent by oral route in Japan for cancer of digestive organs, lung cancer, breast cancer and so on. In this paper, clinical data for the radiation sensitizing effect of PSK in the treatment for the cervical cancer patients is reported. The action mechanism of PSK is still unclear. (Auth.)

  17. The relativity of EGFR and autophagy in the regulating radiation sensitivity of brain glioma cells

    International Nuclear Information System (INIS)

    Radiotherapy is one of the most important methods in the combination therapy against glioma, but resistance of the malignant glioma to radiation limits its clinical contribution. Therefore, it makes great sense to study new mechanisms of radio-resistance. Recent studies show that there is a relationship between EGFR and autophagy in human glioma radiotherapy. More investigations will be needed to select ideal target to enhance the radio-sensitivity of glioma by use of the relationship. (authors)

  18. Protective efficacy of Emblica officinalis Linn. against radiation and cadmium induced biochemical alterations in the liver of Swiss albino mice

    International Nuclear Information System (INIS)

    All organisms living on earth are being perpetually exposed to some amount of radiation originating from a variety of sources. Radiation causes deleterious effects in all forms of life due to increasing utilization and production of modern technology, a simultaneous exposure of organisms to heavy metals is also unavoidable. These heavy metals become toxic when present in large quantities, with increasing the industrial revolution and industrial waste, the emission of cadmium has increased into the environment. Thus concomitant exposure to cadmium chloride and ionizing radiation might produce deleterious effect upon biological system. The total environmental burden of toxicants may have greater effect as against their individual impact as expected by their nature. So interaction between radiation and other toxicants represents a field of great potential importance. In the recent years, immense interest has been developed in the field of chemoprotection against radiation and heavy metals induced changes. In view of the potential for practical application, a variety of compounds are being tested for their radioprotective activities. Among these, Emblica holds a great promise. In light of the above, the present study was aimed to evaluate the protective effect of Emblica against radiation and cadmium induced biochemical alterations in the liver of Swiss albino mice. The animals were exposed to 6.0 Gy of gamma rays with or without cadmium chloride treatment. The Emblica was administered seven days prior to irradiation or cadmium chloride treatment

  19. Experimental study of variations in background radiation and the effect on Nuclear Car Wash sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Church, J; Slaughter, D; Norman, E; Asztalos, S; Biltoft, P

    2007-02-07

    Error rates in a cargo screening system such as the Nuclear Car Wash [1-7] depend on the standard deviation of the background radiation count rate. Because the Nuclear Car Wash is an active interrogation technique, the radiation signal for fissile material must be detected above a background count rate consisting of cosmic, ambient, and neutron-activated radiations. It was suggested previously [1,6] that the Corresponding negative repercussions for the sensitivity of the system were shown. Therefore, to assure the most accurate estimation of the variation, experiments have been performed to quantify components of the actual variance in the background count rate, including variations in generator power, irradiation time, and container contents. The background variance is determined by these experiments to be a factor of 2 smaller than values assumed in previous analyses, resulting in substantially improved projections of system performance for the Nuclear Car Wash.

  20. Radiation sensitivity of fibroblast strains from patients with Usher's syndrome, Duchenne muscular dystrophy, and Huntington's disease

    International Nuclear Information System (INIS)

    The colony-forming ability of 10 normal human fibroblast cell strains and of 10 strains representing 3 degenerative diseases of either nerve or muscle cells was determined after exposure of the cells to X-rays or β-particles from tritiated water. Both methods of irradiation yielded similar comparative results. The fibroblast strains from the 5 Usher's syndrome patients and from 1 of the 2 Huntington's disease patients were hypersensitive to radiation, while those from the 3 Duchenne muscular dystrophy patients and the second Huntington's disease patient had normal sensitivity to radiation. These results indicate both disease-specific and strain-specific differences in the survival of fibroblasts after exposure to ionizing radiation. 38 refs.; 2 figs.; 3 tabs

  1. Potential sensitivity of photosynthesis and isoprene emission to direct radiative effects of atmospheric aerosol pollution

    Science.gov (United States)

    Strada, S.; Unger, N.

    2015-09-01

    A global Earth system model is applied to quantify the impacts of direct anthropogenic aerosol effective radiative forcing on gross primary productivity (GPP) and isoprene emission. The impacts of different pollution aerosol sources (all anthropogenic, biomass burning and non-biomass burning) are investigated by performing sensitivity experiments. On the global scale, our results show that land carbon fluxes (GPP and isoprene emission) are not sensitive to pollution aerosols, even under a global decline in surface solar radiation (direct + diffuse) by ~ 9 %. At the regional scale, plant productivity (GPP) and isoprene emission show a robust but opposite sensitivity to pollution aerosols, in regions where complex canopies dominate. In eastern North America and Europe, anthropogenic pollution aerosols (mainly from non-biomass burning sources) enhance GPP by +8-12 % on an annual average, with a stronger increase during the growing season (> 12 %). In the Amazon basin and central Africa, biomass burning aerosols increase GPP by +2-5 % on an annual average, with a peak in the Amazon basin during the dry-fire season (+5-8 %). In Europe and China, anthropogenic pollution aerosols drive a decrease in isoprene emission of -2 to -12 % on the annual average. Anthropogenic aerosols affect land carbon fluxes via different mechanisms and we suggest that the dominant mechanism varies across regions: (1) light scattering dominates in the eastern US; (2) cooling in the Amazon basin; and (3) reduction in direct radiation in Europe and China.

  2. Radiation Sensitivity of some Food Borne Bacterial Pathogens in Animal Foods and Minced Meat

    International Nuclear Information System (INIS)

    Bacteriological examination of 100 samples of animal food stuffs (fish meal and bone and meat meal; as models of dry food materials) and 50 samples of minced meat (as a model of moist food materials) revealed the isolation of different bacterial pathogens; Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, Proteus spp., Staph. aureus and Salmonella species, in a decreasing order of occurrence. In the experiment; the dry food stuffs were sterilized in autoclave and the minced meat was sterilized by gamma irradiation at 10 kGy. The efficacy of gamma irradiation against the inoculated bacterial isolates (E coli 0157: H7, Salmonella enteritidis and Staph. aureus) in animal food stuffs and minced meat was investigated. Irradiated samples were stored at room temperature (25 degree C) for 2 weeks. The food borne pathogens used in this study showed a difference in radiation sensitivity. E. coli 0157: H7, Staphylococcus aureus and Salmonella enteritidis were eradicated at 1, 2 and 3 kGy, respectively. Also, inoculated pathogens in minced meat were more sensitive to ionizing radiation than dry animal food stuffs. It could be concluded that low doses of gamma irradiation are effective means of inactivating pathogenic bacteria. This radiation sensitivity is related to the bacterial isolates and the evaluated growth

  3. Nonlinear Quantitative Radiation Sensitivity Prediction Model Based on NCI-60 Cancer Cell Lines

    Directory of Open Access Journals (Sweden)

    Chunying Zhang

    2014-01-01

    Full Text Available We proposed a nonlinear model to perform a novel quantitative radiation sensitivity prediction. We used the NCI-60 panel, which consists of nine different cancer types, as the platform to train our model. Important radiation therapy (RT related genes were selected by significance analysis of microarrays (SAM. Orthogonal latent variables (LVs were then extracted by the partial least squares (PLS method as the new compressive input variables. Finally, support vector machine (SVM regression model was trained with these LVs to predict the SF2 (the surviving fraction of cells after a radiation dose of 2 Gy γ-ray values of the cell lines. Comparison with the published results showed significant improvement of the new method in various ways: (a reducing the root mean square error (RMSE of the radiation sensitivity prediction model from 0.20 to 0.011; and (b improving prediction accuracy from 62% to 91%. To test the predictive performance of the gene signature, three different types of cancer patient datasets were used. Survival analysis across these different types of cancer patients strongly confirmed the clinical potential utility of the signature genes as a general prognosis platform. The gene regulatory network analysis identified six hub genes that are involved in canonical cancer pathways.

  4. Regulation of early and delayed radiation responses in rat small intestine by capsaicin-sensitive nerves

    International Nuclear Information System (INIS)

    Purpose: Mast cells protect against the early manifestations of intestinal radiation toxicity, but promote chronic intestinal wall fibrosis. Intestinal sensory nerves are closely associated with mast cells, both anatomically and functionally, and serve an important role in the regulation of mucosal homeostasis. This study examined the effect of sensory nerve ablation on the intestinal radiation response in an established rat model. Methods and Materials: Rats underwent sensory nerve ablation with capsaicin or sham ablation. Two weeks later, a localized segment of ileum was X-irradiated or sham irradiated. Structural, cellular, and molecular changes were examined 2 weeks (early injury) and 26 weeks (chronic injury) after irradiation. The mast cell dependence of the effect of sensory nerve ablation on intestinal radiation injury was assessed using c-kit mutant (Ws/Ws) mast cell-deficient rats. Results: Capsaicin treatment caused a baseline reduction in mucosal mast cell density, crypt cell proliferation, and expression of substance P and calcitonin gene-related peptide, two neuropeptides released by sensory neurons. Sensory nerve ablation strikingly exacerbated early intestinal radiation toxicity (loss of mucosal surface area, inflammation, intestinal wall thickening), but attenuated the development of chronic intestinal radiation fibrosis (collagen I accumulation and transforming growth factor β immunoreactivity). In mast cell-deficient rats, capsaicin treatment exacerbated postradiation epithelial injury (loss of mucosal surface area), but none of the other aspects of radiation injury were affected by capsaicin treatment. Conclusions: Ablation of capsaicin-sensitive enteric neurons exacerbates early intestinal radiation toxicity, but attenuates development of chronic fibroproliferative changes. The effect of capsaicin treatment on the intestinal radiation response is partly mast cell dependent

  5. Numerical Simulation of Sensitivities of Snow Melting to Spectral Composition of the Incoming Solar Radiation

    Institute of Scientific and Technical Information of China (English)

    LI Weiping; SUN Shufen; WANG Siao; LIU Xin

    2009-01-01

    Snow albedo is an important factor influencing the snow surface energy budget and snow melting,yet uncertainties remain in the calculation of spectrally resolved snow surface albedo because the spectral composition (visible versus near infrared) of the incident solar radiation is seldom available. The influence of the spectral composition of the incoming solar radiation on the snow surface albedo, snow surface energy budget, and final snow ablation is investigated through sensitivity experiments of four snow seasons at two open sites in the Alps by using a multi-layer Snow-Atmosphere-Soil-Transfer scheme (SAST). Since the snow albedo in the near infrared (NIR) spectral band is significantly lower than that in the visible (VIS) band, and almost the entire NIR part of the solar radiation is absorbed in the top layer of the snow pack, given a fixed amount of incoming solar radiation, a lower VIS/NIR ratio implies that more NIR radiation is reaching the ground surface and more is absorbed by the top layer of the snow pack, therefore, speeding up the snow melting and increasing the surface runoff, although a lesser part of the solar radiation in the visible band is transmitted into and trapped by the sub-layer of the snow pack. The above VIS/NIR ratio effect of the incoming solar radiation can result in a couple of days difference in the timing of snow ablation and it becomes more significant in late spring when the total solar radiation is intensified with seasonal evolution. Snow aging also slightly intensifies this VIS/NIR ratio effect.

  6. Tumor progression: analysis of the instability of the metastatic phenotype, sensitivity to radiation and chemotherapy

    International Nuclear Information System (INIS)

    The major complications for tumor therapy are 1) tumor spread (metastasis); 2) the mixed nature of tumors (heterogeneity); and 3) the capacity of tumors to evolve (progress). To study these tumor characteristics, the rat 13762NF mammary adenocarcinoma was cloned and studied for metastatic properties and sensitivities to therapy (chemotherapy, radiation and hyperthermia). The cell clones were heterogeneous and no correlation between metastatic potential and therapeutic sensitivities was observed. Further, these phenotypes were unstable during pasage in vitro; yet, the changes were clone dependent and reproducible using different cryoprotected cell stocks. To understand the phenotypic instability, subclones were isolated from low and high passage cell clones. The results demonstrated that 1) tumor cells are heterogeneous for multiple phenotypes; 2) tumor cells are unstable for multiple phenotypes; 3) the magnitude, direction and time of occurrence of phenotypic drift is clone dependent; 4) the sensitivity of cell clones to ionizing radiation (γ or heat) and chemotherapy agents is independent of their metastatic potential; 5) shifts in metastatic potential and sensitivity to therapy may occur simultaneously but are not linked; and 6) tumor cells independently diverge to form several subpopulations with unique phenotypic profiles

  7. The components in the radiation sensitization of bacterial spores by p-nitroacetophenone

    International Nuclear Information System (INIS)

    p-Nitroacetophenone (PNAP) sensitizes Bacillus megaterium spores under anoxic conditions to the lethal effects of 50 kVp X-rays. Concentrations between approximately 5 x 10-4 M and 3.8 x 10-3 M produce the maximum effect, an increase of about 30 per cent over the anoxic response when the spores are irradiated in water. Compounds that scavenge .OH decrease, but cannot completely eliminate, this maximum amount of sensitization. These results indicate that PNAP acts to increase spores' radiation sensitivity through two seperable types of chemical reactions: one which involves .OH and one which does not. Possible mechanisms responsible for these two components of damage are discussed. In these experiments 1/15 M phosphate buffer acts in several unexpected ways. This concentration itself increased the anoxic spore response by about 9 per cent (relative to the anoxic response in water). In addition, although the maximum amounts of sensitization were the same, the amounts of sensitization from lower PNAP cencentrations differed when the suspending fluid was buffer instead of water. An interaction was also seen during the PNAP-t-butanol experiments; again, the responses at low PNAP concentrations were different in buffer and in water. No mechanisms for these actions of this buffer were suggested, although somewhat similar effects may occur with other organisms. Clearly, such effects must be recognized and evaluated before quantitative analyses of the actions of sensitivity-modifying agents can be completed. (author)

  8. Sensitivity of Escherichia coli acrA mutants to psoralen plus near-ultraviolet radiation

    International Nuclear Information System (INIS)

    The sensitivity to psoralen plus near-ultraviolet radiation (PUVA) was compared in a pair of E. coli strains differing at the acrA locus. Survival was determined for both bacteria and phage lambda. AcrA mutant cells were 40 times more sensitive than wild type to the lethal effect of PUVA. Free lambda phage exposed to PUVA survived as well when plated on acrA mutants as on wild type. In contrast, prophage lambda C1857 ind- carried in lysogenic acrA strains was hypersensitive to PUVA. The enhanced sensitivity of bacterial and lambda DNA, when inside acrA cells, was parallel by an increased photobinding of radiolabelled psoralens in the mutant. Binding was increased specifically to DNA rather than to nucleic acids in general. The difference in psoralen-binding ability determined by the acrA gene persisted after permeabilizing treatment of the cells. (orig./AJ)

  9. Radiogenic male breast cancer with in vitro sensitivity to ionizing radiation and bleomycin

    International Nuclear Information System (INIS)

    A cytogenetically normal man with gynecomastia and a family history of diverse cancers developed adenocarcinoma of the breast 30 years following thymic irradiation. In vitro experiments measuring colony-forming ability of cultured skin fibroblasts from family members implied that the patient had a small but significant increase in sensitivity to ionizing radiation, and a moderate increase in sensitivity to bleomycin, a radiomimetic drug. Enhanced radiosensitivity of fibroblasts from the patient's mother, and bleomycin sensitivity of fibroblasts from the sister suggested, but did not prove, that genetic susceptibility affected the risk of radiogenic cancer in this individual. In vitro studies of cancer-prone kindreds are a useful research strategy in delineating mechanisms of carcinogenesis

  10. A new highly sensitive low-Z LiF-based OSL phosphor for radiation dosimetry

    International Nuclear Information System (INIS)

    A new low-Z lithium fluoride-based optical stimulated luminescent (OSL) phosphor is developed. The phosphor shows good OSL properties, and its sensitivity is comparable with that of the commercial Al2O3:C (Landauer, Inc.) phosphor. For the luminescence averaged over initial 3 s, blue stimulated luminescence (BSL) and green stimulated luminescence (GSL) sensitivities were found to be 0.27 and 4 times, respectively, than that of Al2O3:C (Landauer, Inc.). The BSL decay is fast, and the whole signal decays within 3 s; the GSL decay is relatively slow, and the signal decays in 25 s. The fast decay, good sensitivity, good linearity and its near tissue equivalence (Zeff ∼8.14) will make this phosphor suitable for radiation dosimetry particularly in personnel as well as in medical dosimetry. (authors)

  11. Protective role of Tinospora cordifolia extract against radiation-induced qualitative, quantitative and biochemical alterations in testes

    International Nuclear Information System (INIS)

    In today's changing global scenario, ionizing radiation is considered as most potent cause of oxidative stress mediated by free radical flux which induces severe damage at various hierarchical levels in the organization in the living organisms. Testis is a highly prolific tissue with fast cellular renewal and poor antioxidant defense; therefore it becomes an easy target for the radiation-induced free radicals that have long been suggested as major cause of male infertility. Chemical radioprotection is an important strategy to countermeasure the deleterious effects of radiation. Several Indian medicinal plants are rich source of antioxidants and these have been used for the treatment of ailments. Tinospora cordifolia, commonly known as amrita, is one of the plants that have several pharmacological and therapeutic properties. Therefore, the present study was performed to evaluate the deleterious effects of semi lethal dose of gamma radiation on testicular tissue and their possible inhibition by Tinospora cordifolia root extract (TCE). For this purpose, healthy Swiss albino male mice were selected from an inbred colony and divided into four groups. Group I (normal) was administered double distilled water (DDW) volume equal to TCE (75 mg/kg.b.wt/animal) by oral gavage. Group II was orally supplemented TCE as 75 mg/kg. b.wt once daily for 5 consecutive days. Group III (irradiated control) received DDW orally equivalent to TCE for 5 days then exposed to 5 Gy gamma radiation. Group IV (experimental) was administered TCE as in Group II and exposed to radiation (as in Group III). Irradiation resulted into significant decrease in the frequency of different spermatogenic cell counts along with severe histo-pathological lesions up to 7th day of irradiation in testes of irradiated control animals, thereafter, recovery followed towards the normal architecture. TCE pretreatment effectively prevented radiation induced such alterations in cellular counts and testicular injuries by

  12. Sphingosine analog fingolimod (FTY720) increases radiation sensitivity of human breast cancer cells in vitro.

    Science.gov (United States)

    Marvaso, Giulia; Barone, Agnese; Amodio, Nicola; Raimondi, Lavinia; Agosti, Valter; Altomare, Emanuela; Scotti, Valerio; Lombardi, Angela; Bianco, Roberto; Bianco, Cataldo; Caraglia, Michele; Tassone, Pierfrancesco; Tagliaferri, Pierosandro

    2014-06-01

    Radiotherapy is one of the most effective therapeutic strategies for breast cancer patients, although its efficacy may be reduced by intrinsic radiation resistance of cancer cells. Recent investigations demonstrate a link between cancer cell radio-resistance and activation of sphingosine kinase (SphK1), which plays a key role in the balance of lipid signaling molecules. Sphingosine kinase (SphK1) activity can alter the sphingosine-1-phosphate (S1P)/ceramide ratio leading to an imbalance in the sphingolipid rheostat. Fingolimod (FTY720) is a novel sphingosine analog and a potent immunosuppressive drug that acts as a SphK1 antagonist, inhibits the growth, and induces apoptosis in different human cancer cell lines. We sought to investigate the in vitro radiosensitizing effects of FTY720 on the MDA-MB-361 breast cancer cell line and to assess the effects elicited by radiation and FTY720 combined treatments. We found that FTY720 significantly increased anti-proliferative and pro-apoptotic effects induced by a single dose of ionizing radiation while causing autophagosome accumulation. At the molecular level, FTY720 significantly potentiated radiation effects on perturbation of signaling pathways involved in regulation of cell cycle and apoptosis, such as PI3K/AKT and MAPK. In conclusion, our data highlight a potent radiosensitizing effect of FTY720 on breast cancer cells and provide the basis of novel therapeutic strategies for breast cancer treatment. PMID:24657936

  13. Combined radiation-protective and radiation-sensitizing agents. IV. Measurement of intracellular protector concentrations

    International Nuclear Information System (INIS)

    Radiosensitization of hypoxic V79 Chinese hamster cells by 0.5 mM misonidazole at approximately 0-4 degrees C is substantially enhanced by pretreating the cells overnight with 0.1 mM buthionine sulfoximine, which lowers the cellular glutathione content to 5% of control values (from 4 mM to approximately 0.2 mM). The enhanced sensitization is reversed by concentrations of exogenous cysteine that are much lower (0.02 mM) than the original glutathione content. Reduced Co-enzyme A affords reversal of the enhancing effect at concentrations of about 1 mM. Sodium ascorbate gives no protection at all even at concentrations of 2 mM. The intracellular concentration of the reducing agents was measured using a spin-through oil technique. There was no diffusion of Co-A (MW greater than 750) or ascorbate (excluded by charge) into the cells. In contrast, cysteine was rapidly concentrated by factors of 4-10, even at the low temperatures used. Extracellular ascorbate's inability to radioprotect argues against electron transfer across the cell membrane as a mechanism for radioprotection. This mechanism could have explained the ability of exogenous thiols to radioprotect in former studies using glutathione, and in the present studies using Co-A. The potential of cysteine to be concentrated by cells poses a problem in the interpretation of exogenous protection by non-diffusing thiols, since trace contamination by cysteine could lead to the actual protection observed. Cysteine could also be formed by exchange reactions of exogenous thiols with the disulfide of cysteine, present in all media formulations

  14. Soft x rays as a tool to investigate radiation-sensitive sites in mammalian cells

    International Nuclear Information System (INIS)

    It is now clear that the initial geometrical distribution of primary radiation products in irradiated biological matter is fundamental to the observed end point (cell killing, mutation induction, chromosome aberrations, etc.). In recent years much evidence has accumulated indicating that for all radiations, physical quantities averaged over cellular dimensions (micrometers) are not good predictors of biological effect, and that energy-deposition processes at the nanometer level are critical. Thus irradiation of cells with soft x rays whose secondary electrons have ranges of the order of nanometers is a unique tool for investigating different models for predicting the biological effects of radiation. We demonstrate techniques whereby the biological response of the cell and the physical details of the energy deposition processes may be separated or factorized, so that given the response of a cellular system to, say, soft x rays, the response of the cell to any other radiation may be predicted. The special advantages of soft x rays for eliciting this information and also information concerning the geometry of the radiation sensitive structures within the cell are discussed

  15. Soft x rays as a tool to investigate radiation-sensitive sites in mammalian cells

    Energy Technology Data Exchange (ETDEWEB)

    Brenner, D.J.; Zaider, M.

    1983-01-01

    It is now clear that the initial geometrical distribution of primary radiation products in irradiated biological matter is fundamental to the observed end point (cell killing, mutation induction, chromosome aberrations, etc.). In recent years much evidence has accumulated indicating that for all radiations, physical quantities averaged over cellular dimensions (micrometers) are not good predictors of biological effect, and that energy-deposition processes at the nanometer level are critical. Thus irradiation of cells with soft x rays whose secondary electrons have ranges of the order of nanometers is a unique tool for investigating different models for predicting the biological effects of radiation. We demonstrate techniques whereby the biological response of the cell and the physical details of the energy deposition processes may be separated or factorized, so that given the response of a cellular system to, say, soft x rays, the response of the cell to any other radiation may be predicted. The special advantages of soft x rays for eliciting this information and also information concerning the geometry of the radiation sensitive structures within the cell are discussed.

  16. Differential sensitivity of coral larvae to natural levels of ultraviolet radiation during the onset of larval competence.

    KAUST Repository

    Aranda, Manuel

    2011-07-01

    Scleractinian corals are the major builders of the complex structural framework of coral reefs. They live in tropical waters around the globe where they are frequently exposed to potentially harmful ultraviolet radiation (UVR). The eggs and early embryonic stages of some coral species are highly buoyant and remain near the sea surface for prolonged periods of time and may therefore be the most sensitive life stages with respect to UVR. Here, we analysed gene expression changes in five developmental stages of the Caribbean coral Montastraea faveolata to natural levels of UVR using high-density cDNA microarrays (10 930 clones). We found that larvae exhibit low sensitivity to natural levels of UVR during early development as reflected by comparatively few transcriptomic changes in response to UVR. However, we identified a time window of high UVR sensitivity that coincides with the motile planula stage and the onset of larval competence. These processes have been shown to be affected by UVR exposure, and the transcriptional changes we identified explain these observations well. Our analysis of differentially expressed genes indicates that UVR alters the expression of genes associated with stress response, the endoplasmic reticulum, Ca(2+) homoeostasis, development and apoptosis during the motile planula stage and affects the expression of neurogenesis-related genes that are linked to swimming and settlement behaviour at later stages. Taken together, our study provides further data on the impact of natural levels of UVR on coral larvae. Furthermore, our results might allow a better prediction of settlement and recruitment rates after coral spawning events if UVR climate data are taken into account.

  17. Folic acid deficiency increases chromosomal instability, chromosome 21 aneuploidy and sensitivity to radiation-induced micronuclei

    International Nuclear Information System (INIS)

    Folic acid deficiency can lead to uracil incorporation into DNA, hypomethylation of DNA, inefficient DNA repair and increase chromosome malsegregation and breakage. Because ionising radiation increases demand for efficient DNA repair and also causes chromosome breaks we hypothesised that folic acid deficiency may increase sensitivity to radiation-induced chromosome breakage. We tested this hypothesis by using the cytokinesis-block micronucleus assay in 10 day WIL2-NS cell cultures at four different folic acid concentrations (0.2, 2, 20, and 200 nM) that span the 'normal' physiological range in humans. The study showed a significant dose-dependent increase in frequency of binucleated cells with micronuclei and/or nucleoplasmic bridges with decreasing folic acid concentration (P < 0.0001, P = 0.028, respectively). These biomarkers of chromosomal instability were also increased in cells irradiated (1.5 Gy γ-rays) on day 9 relative to un-irradiated controls (P < 0.05). Folic acid deficiency and γ-irradiation were shown to have a significant interactive effect on frequency of cells containing micronuclei (two-way ANOVA, interaction P 0.0039) such that the frequency of radiation-induced micronucleated cells (i.e. after subtracting base-line frequency of un-irradiated controls) increased with decreasing folic acid concentration (P-trend < 0.0001). Aneuploidy of chromosome 21, apoptosis and necrosis were increased by folic acid deficiency but not by ionising radiation. The results of this study show that folate status has an important impact on chromosomal stability and is an important modifying factor of cellular sensitivity to radiation-induced genome damage

  18. Food restriction alters pramipexole-induced yawning, hypothermia, and locomotor activity in rats: Evidence for sensitization of dopamine D2 receptor-mediated effects

    OpenAIRE

    Collins, Gregory T; Calinski, Diane M.; Newman, Amy Hauck; Grundt, Peter; Woods, James H.

    2008-01-01

    Food restriction enhances sensitivity to the reinforcing effects of a variety of drugs of abuse including opiates, nicotine, and psychostimulants. Food restriction has also been shown to alter a variety of behavioral and pharmacological responses to dopaminergic agonists including an increased sensitivity to the locomotor stimulatory effects of direct- and indirect-dopamine agonists, elevated extracellular dopamine levels in responses to psychostimulants, as well as suppression of agonist-ind...

  19. Patterns of dioxin-altered mRNA expression in livers of dioxin-sensitive versus dioxin-resistant rats

    Energy Technology Data Exchange (ETDEWEB)

    Franc, Monique A. [University of Toronto, Department of Pharmacology and Toxicology, Medical Sciences Building, Toronto, ON (Canada); Johnson and Johnson Pharmaceutical Research and Development, Department of Pharmacogenomics, 1000 Route 202 South, P.O. Box 300, Raritan, NJ (United States); Moffat, Ivy D.; Boutros, Paul C.; Okey, Allan B. [University of Toronto, Department of Pharmacology and Toxicology, Medical Sciences Building, Toronto, ON (Canada); Tuomisto, Jouni T.; Tuomisto, Jouko [National Public Health Institute, Department of Environmental Health, Centre for Environmental Health Risk Analysis, Kuopio (Finland); Pohjanvirta, Raimo [University of Helsinki, Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, Helsinki (Finland)

    2008-11-15

    Dioxins exert their major toxicologic effects by binding to the aryl hydrocarbon receptor (AHR) and altering gene transcription. Numerous dioxin-responsive genes previously were identified both by conventional biochemical and molecular techniques and by recent mRNA expression microarray studies. However, of the large set of dioxin-responsive genes the specific genes whose dysregulation leads to death remain unknown. To identify specific genes that may be involved in dioxin lethality we compared changes in liver mRNA levels following exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in three strains/lines of dioxin-sensitive rats with changes in three dioxin-resistant rat strains/lines. The three dioxin-resistant strains/lines all harbor a large deletion in the transactivation domain of the aryl hydrocarbon receptor (AHR). Despite this deletion, many genes exhibited a ''Type-I'' response - that is, their responses were similar in dioxin-sensitive and dioxin-resistant rats. Several genes that previously were well established as being dioxin-responsive or under AHR regulation emerged as Type-I responses (e.g. CYP1A1, CYP1A2, CYP1B1 and Gsta3). In contrast, a relatively small number of genes exhibited a Type-II response - defined as a difference in responsiveness between dioxin-sensitive and dioxin-resistant rat strains. Type-II genes include: malic enzyme 1, ubiquitin C, cathepsin L, S-adenosylhomocysteine hydrolase and ferritin light chain 1. In silico searches revealed that AH response elements are conserved in the 5'-flanking regions of several genes that respond to TCDD in both the Type-I and Type-II categories. The vast majority of changes in mRNA levels in response to 100 {mu}g/kg TCDD were strain-specific; over 75% of the dioxin-responsive clones were affected in only one of the six strains/lines. Selected genes were assessed by quantitative RT-PCR in dose-response and time-course experiments and responses of some genes were

  20. Competition and sensitivity of wheat and wild oat exposed to enhanced UV-B radiation at different densities under field conditions

    International Nuclear Information System (INIS)

    The influence of enhanced UV-B radiation (approximating a 15% ozone layer reduction) on competitive interaction between spring wheat (Triticum aestivum) and wild oat (Avena fatua) was examined in the field. The density-dependent mortality of both wheat and wild oat did not exhibit a significant difference between control and UV-B treatment conditions. A relatively high degree of competitive stress enhanced the effects of UV-B stress on biomass reduction. The relative competitive status of wheat in terms of total biomass increased under UV-B enhancement while it decreased when based upon grain production. Shifts in competitive balance occurred with significant changes in total biomass, especially when plants grew at higher densities in monocultures and mixtures. The sensitivity of wild oat to intensification of UV-B radiation at higher densities in mixtures was greater than that at lower densities. At all densities examined, wheat grown in mixture was significantly less sensitive to UV-B radiation than that in monoculture, and just the opposite for wild oat. The density of monocultures did not alter the response index (RI) of wheat and wild oat to enhanced UV-B radiation. (author)

  1. Influence of individual radiation sensitivity on GPA gene mutation frequency in medical diagnostic X-ray workers

    International Nuclear Information System (INIS)

    Objective: To study the influence of individual radiation sensitivity on GPA gene mutation frequency and the way to adjust it. Methods: Comet assay, cytokinesis-block micronucleus plus 3AB index technique, and multiple linear regression were used to determine the influence of individual radiation sensitivity on GPA gene mutation frequency in medical diagnostic X-ray workers, and then the fitted equation of multiple linear regression was obtained. Results: There was individual difference in radiation sensitivity among medical diagnostic X-ray workers, which is a factor influencing GPA gene mutation frequency. The stronger the individual radiation sensitivity, the higher the GPA gene mutation frequency. The correlation between GPA gene mutation frequency and radiation dose was strengthened after it was adjusted by the individual radiation sensitivity. The equation of multiple linear regression for GPA gene mutation frequency was obtained by the multiple factor analysis: YNφ=24.7 x 10-6 + 0.5 x 10-6X1-99.5 x 10-6X2 + 1.7 x 10-6X3, and the correlation coefficient r=0.673. Conclusions: The relationship between GPA Nφ gene mutation frequency and cumulative dose is improved by adjustment for individual radiation sensitivity. The accumulative dose estimated by using the multiple linear regressions is approximate to the dose estimated by physical method, thus it decreases the uncertainty of estimating cumulative dose and forecasting cancer risk by using GPA gene mutation frequency

  2. Radiation-induced grafting of thermo and pH sensitive polymers

    International Nuclear Information System (INIS)

    Complete text of publication follows. Radiation processing has many advantages over other conventional methods. When using radiation for material processing, no catalysts or additives are needed in order to initiate the reaction. Polymeric films were modified by gamma-radiation grafting of pH and thermo sensitive monomers by one and two step methods, using the preirradiation and the direct methods. The effects of the absorbed dose, monomer concentration and reaction time were investigated. The surface chemistry of grafted samples was analyzed by FTIR-ATR spectroscopy, while their thermal properties were analyzed by TGA and DSC. The stimuli-responsive behavior was studied by swelling and contact angle in water, as well as by DSC. Sensitive films presented a critical pH point and low critical solution temperature. Temperature and pH stimuli-responsive macromolecular materials have attracted great attention because of their obvious applications in biomedicine and biotechnology. This work was supported by DGAPA-UNAM Grant IN200208.

  3. Studies on the Mechanism of Radiation Resistance in Micrococcus Radiodurans and its Sensitization

    International Nuclear Information System (INIS)

    Efficient and accurate repair of radiation-induced lesions in M. radiodurans was investigated as to the cause of its extreme radioresistance. The cells were made permeable to deoxyribonucleoside triphosphate by treatment with non-ionic detergent, Triton X-100. After irradiation with 2 krad gamma rays more than 80% of the single-strand scissions were rejoined in the permeable cells within 10 min at 37°C. This fast repair process requires the presence of deoxyribonucleoside triphosphates and NAD. However, rejoining of DNA strand scission was incomplete after prolonged incubation in the permeable cells. This suggests that alternate repair reaction(s) is necessary for complete recovery. The other type of radiation lesion was found by postirradiation incubation at non-permissive temperature, which markedly sensitizes this bacterium to radiation. Postincubation at this temperature also sensitizes the cells to chemicals that damage DNA. The extreme radioresistance of this bacterium was also lost by mutation and an isolated radiosensitive mutant showed almost the same radiosensitivity as E. coli K12 or B/r. These results are discussed in connection with the extreme radioresistance of M. radiodurans. (author)

  4. Modification of the cellular heat sensitivity of cucumber by growth under supplemental ultraviolet-B radiation

    International Nuclear Information System (INIS)

    The effect of ultraviolet B (UV-B) radiation on the thermal sensitivity of cucumber (Cucumis sativus L.) was studied using UV-B-sensitive cv Poinsett 76 and UV-B-resistant cv Ashley grown under control and elevated (300 mW m-2) UV-B radiation levels. Using both cotyledon and leaf discs, the ability of the tissue to reduce triphenyl tetrazolium chloride (TTC) was determined after treatment at 50 degrees C for various times. Semilogarithmic plots of TTC reduction as a function of time at 50 degrees were curvilinear. They were monophasic for the control cucumber and biphasic for cucumber grown in the presence of elevated UV-B. Treatment of cucumber plants at 37 degrees C for 24 h or of tissue discs at acute UV-B levels for 1 h further modified their response to elevated temperature. These results suggest that growth of cucumber under enhanced UV-B radiation levels increased its ability to withstand elevated temperatures. 19 refs., 2 figs., 2 tabs

  5. Studies on the mechanism of radiation resistance in Micrococcus radiodurans and its sensitization

    International Nuclear Information System (INIS)

    Efficient and accurate repair of radiation-induced lesions in M. radiodurans was investigated as to the cause of its extreme radioresistance. The cells were made permeable to deoxyribonucleoside triphosphate by treatment with non-ionic detergent, Triton X-100. After irradiation with 2 krad gamma rays more than 80% of the single-strand scissions were rejoined in the permeable cells within 10 min at 370C. This fast repair process requires the presence of deoxyribonucleoside triphosphates and NAD. However, rejoining of DNA strand scission was incomplete after prolonged incubation in the permeable cells. This suggests that alternate repair reaction(s) is necessary for complete recovery. The other type of radiation lesion was found by post-irradiation incubation at non-permissive temperature, which markedly sensitizes this bacterium to radiation. Postincubation at this temperature also sensitizes the cells to chemicals that damage DNA. The extreme radioresistance of this bacterium was also lost by mutation and an isolated radiosensitive mutant showed almost the same radiosensitivity as E. coli K12 or B/r. These results are discussed in connection with the extreme radioresistance of M. radiodurans. (author)

  6. Folic acid deficiency increases sensitivity to genome damage by ionising radiation

    International Nuclear Information System (INIS)

    Folic acid deficiency can lead to uracil misincorporation and disable DNA repair, by decreasing thymidine concentration. It is hypothesized that folic acid is an important micronutrient in the prevention of chromosome damage induced by gamma-irradiation. In this study the impact of folic acid deficiency on the chromosome damage and chromosome 21 aneuploidy by gamma-radiation was determined using the cytokinesis-block micronucleus assay in long term WIL2-NS cultures in cell culture medium with 4 different folic acid concentrations (0.2 nM, 2 nM, 20 nM and 200 nM). The study showed a significant increase of 55.5% in micronucleus frequency with decreasing folic acid concentration (P < 0.0001). Additionally, there was a significant difference of 46.5% and 50.1% in micronucleus frequency and of nucleoplasmic bridge frequency, respectively, between the control and irradiated (1.5 Gy) group (P < 0.05). Folic acid deficiency caused an increase of 51.7% in micronucleus frequency (P < 0.0001) and of 7.1% nucleoplasmic bridge frequency (P = 0.0280) in irradiated cultures when compared to irradiated folic acid replete cultures. Folic acid deficiency and gamma-radiation were shown to have a significant interactive effect on micronucleus frequency (Two-way ANOVA, P < 0.0001). Apoptosis and necrosis were increased by folic acid deficiency but they were not significantly altered by ionising radiation exposure. Chromosome 21 aneuploidy was significantly increased (P <0.05) by folic acid deficiency but not by ionising radiation and there was no significant interaction between these two factors. The results show that folic acid deficiency induces chromosome 21 aneuploidy by non-disjunction as well as inducing chromosome breaks and chromosome rearrangements. In conclusion, folic acid deficiency interacts significantly with ionising radiation in inducing chromosome damage that leads to the formation of micronuclei (e.g. chromosome breaks and chromosome loss)

  7. Role of Rosemary leaves extract against radiation-induced hematological and biochemical alterations in mice

    OpenAIRE

    Acharya Garima S.; Goyal Pradeep K.

    2008-01-01

    The present paper is a study of the modulatory effect of Rosmarinus officinalis leaves extract on radiation-induced hematological and biochemical changes in Swiss albino mice. The dose reduction factor for the Rosemary extract against gamma rays was calculated 1.53 from LD50/30 values. The Rosemary extract was administered orally for 5 consecutive days prior to radiation exposure. The hematological and biochemical parameters were assessed from day 1 to 30 post-irradiation intervals. The total...

  8. Temperature and hydration effects on absorbance spectra and radiation sensitivity of a radiochromic medium

    International Nuclear Information System (INIS)

    The effects of temperature on real time changes in optical density (ΔOD) of GAFCHROMIC EBT film were investigated. The spectral peak of maximum change in absorbance (λmax) was shown to downshift linearly when the temperature of the film was increased from 22 to 38 degree sign C. The ΔOD values were also shown to decrease linearly with temperature, and this decrease could not be attributed to the shift in λmax. A compensation scheme using λmax and a temperature-dependent correction factor was investigated, but provided limited improvement. Part of the reason may be the fluctuations in hydration of the active component, which were found to affect both position of absorbance peaks and the sensitivity of the film. To test the effect of hydration, laminated and unlaminated films were desiccated. This shifted both the major and minor absorbance peaks in the opposite direction to the change observed with temperature. The desiccated film also exhibited reduced sensitivity to ionizing radiation. Rehydration of the desiccated films did not reverse the effects, but rather gave rise to another form of the polymer with absorbance maxima upshifted further 20 nm. Hence, the spectral characteristics and sensitivity of the film can be dependent on its history, potentially complicating both real-time and conventional radiation dosimetry.

  9. Radiation sensitivity of graphene field effect transistors and other thin film architectures

    Science.gov (United States)

    Cazalas, Edward

    An important contemporary motivation for advancing radiation detection science and technology is the need for interdiction of nuclear and radiological materials, which may be used to fabricate weapons of mass destruction. The detection of such materials by nuclear techniques relies on achieving high sensitivity and selectivity to X-rays, gamma-rays, and neutrons. To be attractive in field deployable instruments, it is desirable for detectors to be lightweight, inexpensive, operate at low voltage, and consume low power. To address the relatively low particle flux in most passive measurements for nuclear security applications, detectors scalable to large areas that can meet the high absolute detection efficiency requirements are needed. Graphene-based and thin-film-based radiation detectors represent attractive technologies that could meet the need for inexpensive, low-power, size-scalable detection architectures, which are sensitive to X-rays, gamma-rays, and neutrons. The utilization of graphene to detect ionizing radiation relies on the modulation of graphene charge carrier density by changes in local electric field, i.e. the field effect in graphene. Built on the principle of a conventional field effect transistor, the graphene-based field effect transistor (GFET) utilizes graphene as a channel and a semiconducting substrate as an absorber medium with which the ionizing radiation interacts. A radiation interaction event that deposits energy within the substrate creates electron-hole pairs, which modify the electric field and modulate graphene charge carrier density. A detection event in a GFET is therefore measured as a change in graphene resistance or current. Thin (micron-scale) films can also be utilized for radiation detection of thermal neutrons provided nuclides with high neutron absorption cross section are present with appreciable density. Detection in thin-film detectors could be realized through the collection of charge carriers generated within the

  10. The Mediterranean summertime ozone maximum: global emission sensitivities and radiative impacts

    Directory of Open Access Journals (Sweden)

    N. A. D. Richards

    2013-03-01

    Full Text Available The Mediterranean troposphere exhibits a marked and localised summertime ozone maximum, which has the potential to strongly impact regional air quality and radiative forcing. The Mediterranean region can be perturbed by long-range pollution import from Northern Europe, North America and Asia, in addition to local emissions, which may all contribute to regional ozone enhancements. We exploit ozone profile observations from the Tropospheric Emission Spectrometer (TES and the Global Ozone Monitoring Experiment-2 (GOME-2 satellite instruments, and an offline 3-D global chemical transport model (TOMCAT to investigate the geographical and vertical structure of the summertime tropospheric ozone maximum over the Mediterranean region. We show that both TES and GOME-2 are able to detect enhanced levels of ozone in the lower troposphere over the region during the summer. These observations, together with surface measurements, are used to evaluate the TOMCAT model's ability to capture the observed ozone enhancement. The model is used to quantify sensitivities of the ozone maximum to anthropogenic and natural volatile organic compound (VOC emissions, anthropogenic NOx emissions, wildfire emissions and long-range import of ozone and precursors. Our results show a dominant sensitivity to natural VOC emissions in the Mediterranean basin over anthropogenic VOC emissions. However, local anthropogenic NOx emissions are result in the overall largest sensitivity in near-surface ozone. We also show that in the lower troposphere, global VOC emissions account for 40% of the ozone sensitivity to VOC emissions in the region, whereas, for NOx the ozone sensitivity to local sources is 9 times greater than that for global emissions at these altitudes. However, in the mid and upper troposphere ozone is most sensitive to non-local emission sources. In terms of radiative effects on regional climate, ozone contributions from non-local emission sources are more important, as

  11. Variability of individual normal tissue radiation sensitivity. An international empirical evaluation of endogenous and exogenous

    International Nuclear Information System (INIS)

    Background: The variability of normal-tissue response is of major concern for radiation therapy. Multiple endogenous and exogenous factors are qualitatively known to alter the acute and late tissue response. Which of them are regarded most important by the European radiation oncologists and what is, empirically, their quantitative influence on the acute or late tissue tolerance? Methods: In August 1997, we sent a questionnaire to 255 European radiation oncology departments. Among others, the questionnaire asked for endogenous and exogenous factors modifying the tissue response to radiation therapy and their quantitative influence on the acute and late radiation morbidity (TD5/5). Fifty-five questionnaires (21.5%) were answered. Results: Empirically, the most important endogenous factors to modify the acute tissue tolerance are (a) metabolic/other diseases with macro- or microangiopathia (17 answers [a]/32% mean decrease of tissue tolerance), (b) collagen diseases (9 a/37%) and (c) immune diseases (5 a/53%). As endogenous response modifiers for the TD5/5 are recognized (a) metabolic or other diseases leading to marcro- or microangiopathia (15 a/31%), (b) collagen diseases (11 a/38%) and (c) immune diseases (2 a/50%). Inflammations from any reason are assumed to alter the acute tissue tolerance by (6 a/26%) and the TD5/5 by (10 a/24%). Exogenous modifiers of the acute tissue response mentioned are (a) smoking (34 a/44%), (b) alcohol (23 a/45%), (c) nutrition/diets (16 a/45%), (d) hygiene (9 a/26%) and (e) medical therapies (10 a/37%). Exogenous factors assumed to influence the TD5/5 are (a) smoking (22 a/40%), (b) alcohol (15 a/38%), (c) nutrition/diets (9 a/48%), (d) hygiene (5 a/34%) and (e) medical therapies (10 a/30%). Conclusions: Exogenous factors are regarded more important by number and extent on the acute and late tissue response than endogenous modifiers. Both may have an important influence on the individual expression of normal tissue response. (orig.)

  12. Alterations in biochemical and physiological characters in radiation-induced mutants of grain legumes

    International Nuclear Information System (INIS)

    Selected examples from different grain legumes are studied. The biochemically and physiologically detectable alterations in distintc characters as caused by the action of mutant genes are presented comparatively. The interactions between different mutant genes in order to evaluated the influence of the genotypic constitution on the expression of mutated genes are emphasized. (M.A.C.)

  13. The effects of altered levels of UV-B radiation on an Antarctic grass and lichen

    NARCIS (Netherlands)

    Lud, D.; Huiskes, A.H.L.; Moerdijk-Poortvliet, T.C.W.; Rozema, J.J.

    2001-01-01

    We report a long-term experiment on the photosynthetic response of natural vegetation of Deschampsia antarctica (Poaceae) and Turgidosculum complicatulum (Lichenes) to altered UV-B levels on Leonie Island, Antarctica. UV-B above the vegetation was reduced by filter screens during two seasons. Half o

  14. Pomegranate Alleviates Oxidative Damage and Neurotransmitter Alterations in Rats Brain Exposed to Aluminum Chloride and/or Gamma Radiation

    International Nuclear Information System (INIS)

    Aluminum and gamma radiation, both are potent neurotoxins and have been implicated in many human neuro degenerative diseases. The present study was designed to investigate the role of pomegranate in alleviating oxidative damage and alteration of neurotransmitters in the brain of rats exposed to aluminum chloride (AlCl3), and/or gamma radiation (IR). The results revealed that rats whole body exposed to γ- rays, (1 Gy/week up to 4 Gy), and/or administered aluminum chloride (35 mg/kg body weight), via gavages for 4 weeks, resulted in brain tissue damage, featuring by significant increase of the level of thiobarbituric acid reactive substances (TBARS), and advanced oxidation protein products (AOPP), associated with significant decrease of superoxide dismutase (SOD) and catalase (CAT) activities, as well as glutathione (GSH) content indicating occurrence of oxidative stress. A significant decrease of serotonin (5-HT) level associated with a significant increase of 5-hydroxyindole acetic acid (5-HIAA), in addition to a significant decrease in dopamine (DA), norepinephrine (NE) and epinephrine (EPI) contents recorded at the 1st, 7th and 14th day post-irradiation, indicating alterations in the metabolism of brain monoamines. On the other hand, the results exhibited that, supplementation of rats with pomegranate, via gavages, at a dose of 3 ml /kg body weight/ day, for 4 weeks along with AlCl3 with or without radiation has significantly ameliorated the changes occurred in the mentioned parameters and the values returned close to the normal ones. It could be concluded that pomegranate, by its antioxidant constituents might antagonize brain oxidative damage and minimize the severity of aluminum (Al), and/or radiation-induced neurotransmitters disorders

  15. Colchicine sensitizes human hepatocellular carcinoma cells to damages caused by radiation

    Institute of Scientific and Technical Information of China (English)

    Chia-Yuan Liu; Hui-Fen Liao; Shou-Chuan Shih; Shee-Chan Lin; Wen-Hsiung Chang; Cheng-Hsin Chu; Tsang-En Wang; Yu-Jen Chen

    2005-01-01

    AIM: We studied the effect of colchicine combined with radiation on the survival of human hepatocellular carcinoma (HCC) HA22T/VGH cells.METHODS: Twenty-four hours after treatment with 0-8 ng/mL colchicine, HA22T/VGH cells were irradiated at various doses (0, 1, 2, 4, and 8 Gy). Colony assay was performed to assess the surviving cell fraction. Survival curves were fitted by using a linear-quadratic model to estimate the sensitizer enhancement ratio (SER). Flow cytometry was used for cell cycle analysis.RESULTS: Colchicine at lower concentrations (1 and 2 ng/mL) had obvious synergy with radiation to inhibit HCC cell growth, whereas higher concentrations (4 and 8 ng/mL) had only additive effect to radiation. Pretreatment with 1 and 2 ng/mL colchicine for 24-h enhanced cell killing by radiation with SERs of 1.21 and 1.53, respectively.G2/M arrest was only observed with higher colchicine doses (8 and 16 ng/mL) after 24-h treatment; this effect was neither seen with lower doses (1, 2, and 4 ng/mL)nor with any dose after only 1 h of treatment.CONCLUSION: Our results suggest that colchicine has potential as an adjunct to radiotherapy for HCC treatment.Lower doses of colchicine possess radiosensitizing effects via some mechanism other than G2/M arrest. Further study is necessary to elucidate the mechanism.

  16. Increasing oxygenation and radiation sensitivity following photodynamic therapy with verteporfin in the RIF-1 tumor

    Science.gov (United States)

    Pogue, Brian W.; O'Hara, Julia A.; Demidenko, Eugene; Wilmot, Carmen M.; Chen, Bin; Swartz, Harold M.; Hasan, Tayyaba

    2003-06-01

    The combination of verteporfin-based photodynamic therapy (PDT) wiht radiaiton therapy from an orthovoltage device has been examiend in the radiation induced fibrosarcoma tumor model. PDT with verteporfin using a 3 hour delay between injection and the time of optical irradiation has been shown to cause a significant rise in overlal tumor oxygenation. It was huypothesized that this mechanism arises from the reduced oxygen consumption from cells where the PDT has targeted the mitochondria and shut down cellular respiration. Tumor blood flow was measured and found to be still be patent immediately following therapy. This increasing oxygenation was thought to provide an opportunity to increase the radiation sensitivity of the tumor immediately following PDT. When this type of treatment was combined with radiation therapy, a delay in the tumor regrowth time demonstrated that the combined effect was greater than additive. Further study of this phenomenon will provide a more complete mechanistic understanding of the effect and possibly provide a viable pre-treatment for radiation therapy of tumore that increases the therapeutic ratio. This effect could be used to either increase the radiaton dose without increasing the side effects or decrease the dose needed for the same effect on the tumor.

  17. Prenatal stress alters progestogens to mediate susceptibility to sex-typical, stress-sensitive disorders, such as drug abuse: a review

    Directory of Open Access Journals (Sweden)

    Cheryl A Frye

    2011-10-01

    Full Text Available Maternal-offspring interactions begin prior to birth. Experiences of the mother during gestation play a powerful role in determining the developmental programming of the central nervous system. In particular, stress during gestation alters developmental programming of the offspring resulting in susceptibility to sex-typical and stress-sensitive neurodevelopmental, neuropsychiatric and neurodegenerative disorders. However, neither these effects, nor the underlying mechanisms, are well understood. Our hypothesis is that allopregnanolone, during gestation, plays a particularly vital role in mitigating effects of stress on the developing fetus and may mediate, in part, alterations apparent throughout the lifespan. Specifically, altered balance between glucocorticoids and progestogens during critical periods of development (stemming from psychological, immunological, and/or endocrinological stressors during gestation may permanently influence behavior, brain morphology, and/or neuroendocrine-sensitive processes. 5α-reduced progestogens are integral in the developmental programming of sex-typical, stress-sensitive, and/or disorder-relevant phenotypes. Prenatal stress may alter these responses and dysregulate allopregnanolone and its normative effects on stress axis function. As an example of a neurodevelopmental, neuropsychiatric and/or neurodegenerative process, this review focuses on responsiveness to drugs of abuse, which is sensitive to prenatal stress and progestogen milieu. This review explores the notion that allopregnanolone may effect, or be influenced by, prenatal stress, with consequences for neurodevelopmental-, neuropsychiatric- and/or neurodegenerative- relevant processes, such as addiction.

  18. Radiation synthesis of the water-soluble, temperature sensitive polymer, copolymer and study on their properties

    International Nuclear Information System (INIS)

    In order to obtain the water-soluble, temperature sensitive polymer and activated copolymer, the radiation polymerization of N-isopropylacrylamide (NIPAAm), radiation copolymerization of NIPAAm and N-acryloxysuccide (NASI) in aqueous solution or in buffer solution (PBS pH = 7.4) have been carried out by γ-rays from 60Co source at room temperature. The optimum dose range (1-7 kGy), dose rate (>40 Gy/min) and monomer concentration (1%) were chosen through determining the monomer conversion yield and molecular weight (Mw = 6.8 x 105) of product. Synthesis of the reversible linear polymer was performed in tetrahydrofuran (THF) as well. In this way a white powder product could be obtained which possesses of thermally reversible property too, when it was dissolved in water or PBS. The only disadvantages of this method is that the molecular weight of the polymer produced in THF was much lower than that in aqueous solution

  19. High-sensitivity, high-resolution measurements of radiated power on TEXT-U

    International Nuclear Information System (INIS)

    Investigations of a possible radiation drive of edge turbulence in tokamaks require sensitive radiated power measurements having high temporal and spatial resolution. The authors use a commercially available 16-element X-UV-enhanced photodiode array having essentially 100% quantum efficiency from ∼ 25 eV to ≥ 6 keV. The frequency response is presently limited by the amplifiers to ∼ 50 kHz, although the ultimate response is expected to be much higher (>200 kHz). Each element's view is ∼ 0.4 cm wide along the major radius at the plasma midplane while the view of the entire array is ∼ 6.3 cm wide and is scannable over the entire plasma cross section. The details of the system as well as observations of fine spatial structures and fluctuations undetectable by conventional bolometers are presented

  20. Sensitization of prostate cancer to ionizing radiation by targeting poly(ADP-robose) polymerase: preclinical studies

    International Nuclear Information System (INIS)

    Poly(ADP-ribose) polymerase (PARP) is a DNA-binding enzyme which plays important roles in the maintenance of genome stability, immediate cellular responses to DNA damage, and apoptosis. A DNA-binding domain of PARP (PARP-DBD) acts as a dominant-negative mutant by binding to DNA strand breaks irreversibly and sensitizing mammalian cells to DNA-damaging agents (1, 2). To direct the expression of human PARP-DBD to prostate we developed recombinant plasmids expressing the PARP-DBD under the control of the 5'-flanking sequences of the human prostate-specific antigen (PSA) gene. In vitro studies revealed that PSA promoter driven expression of the PARP-DBD showed prostate tissue specificity and androgen responsiveness and sensitized LNCaP cells to DNA-damaging agents, such as ionizing radiation and etoposide (3). To assess the efficiency of this strategy in vivo, we developed a cationic liposome-mediated gene delivery of PARP-DBD plasmid in tumor xenografts of PSA producing and androgen sensitive prostate cancer cells (LNCaP and 22Rv1). Tumor bearing mice were treated with intratumoral liposome-complexed PARP-DBD (LE-PARP-DBD), ionizing radiation (IR) or a combination of LE-PARP-DBD and IR. Control groups received blank liposomes or were left untreated. Administration of LE-PARP-DBD resulted in expression of dominant-negative mutant of PARP in tumor cells and enhanced radiation-induced inhibition of tumor growth. These results provide a proof-of- principle for a novel therapeutic strategy to control prostate cancer. The study was supported in part by grants from the U.S. Army Medical Research and Development Command DAMD 17-00-1-0019 and DAMD 17-00-1-0276 (to V.S.). (1) J.Biol.Chem., 265:18721-18724, 1990; (2) Cancer Research, 58: 3495-3498, 1998; (3) Cancer Research, 62: 6879-6883, 2002

  1. Potential sensitivity of photosynthesis and isoprene emission to direct radiative effects of atmospheric aerosol pollution

    Science.gov (United States)

    Strada, Susanna; Unger, Nadine

    2016-04-01

    A global Earth system model is applied to quantify the impacts of direct anthropogenic aerosol effective radiative forcing on gross primary productivity (GPP) and isoprene emission. The impacts of different pollution aerosol sources (anthropogenic, biomass burning, and non-biomass burning) are investigated by performing sensitivity experiments. The model framework includes all known light and meteorological responses of photosynthesis, but uses fixed canopy structures and phenology. On a global scale, our results show that global land carbon fluxes (GPP and isoprene emission) are not sensitive to pollution aerosols, even under a global decline in surface solar radiation (direct + diffuse) by ˜ 9 %. At a regional scale, GPP and isoprene emission show a robust but opposite sensitivity to pollution aerosols in regions where forested canopies dominate. In eastern North America and Eurasia, anthropogenic pollution aerosols (mainly from non-biomass burning sources) enhance GPP by +5-8 % on an annual average. In the northwestern Amazon Basin and central Africa, biomass burning aerosols increase GPP by +2-5 % on an annual average, with a peak in the northwestern Amazon Basin during the dry-fire season (+5-8 %). The prevailing mechanism varies across regions: light scattering dominates in eastern North America, while a reduction in direct radiation dominates in Europe and China. Aerosol-induced GPP productivity increases in the Amazon and central Africa include an additional positive feedback from reduced canopy temperatures in response to increases in canopy conductance. In Eurasia and northeastern China, anthropogenic pollution aerosols drive a decrease in isoprene emission of -2 to -12 % on an annual average. Future research needs to incorporate the indirect effects of aerosols and possible feedbacks from dynamic carbon allocation and phenology.

  2. Protective effects of Punica Granatum (L) and synthetic ellagic acid on radiation induced biochemical alterations in Swiss albino mice

    International Nuclear Information System (INIS)

    Ionizing radiations produce deleterious effects in the living organisms and the rapid technological advancement has increased human exposure to ionizing radiations enormously. Radiotherapy, which is a chief modality to treat cancer, faces a major drawback because it produces severe side effects developed due to damage to normal tissue by reactive oxygen species (ROS). Recent studies have indicated that some commonly used medicinal plants may be good sources of potent but non-toxic radioprotectors. The pomegranate, Punica granatum L., an ancient, mystical, and highly distinctive fruit, is the predominant member of the Punicaceae family. It is used in several systems of medicine for a variety of ailments. The objective of the present study was to investigate the protective effects of ethanolic extracts of pomegranate whole fruit (EPWF) and seeds (EPS) and Synthetic Ellagic acid (EA) against Electron beam radiation(EBR) induced biochemical alterations in Swiss albino mice. The extracts and synthetic compound were assessed for its radical scavenging property by DPPH radical scavenging and Ferric Reducing Antioxidant Power assays. The animals were exposed to sub-lethal dose (6 Gy) of Electron Beam Radiation and then treated with 200 mg/kg body wt. of pomegranate extracts and synthetic ellagic acid for 15 consecutive days. The biochemical estimations were carried out in the liver homogenate of the sacrificed animals. Radiation induced depletion in the level of reduced glutathione and total antioxidant capacity were prevented significantly by EPWF, EPS and EA administration. Also there was significant reduction in the levels of membrane lipid peroxidation in the treated groups compared to irradiated control. The findings of our study indicate the protective efficacy of pomegranate extracts and synthetic ellagic acid on radiation induced biochemical changes in mice may be due to its free radical scavenging and increased antioxidant levels. (author)

  3. Radiation-induced Alterations in Immune Response to Staphylococcus aureus Infection

    International Nuclear Information System (INIS)

    In an age when medical advances and terrorist threats frequently make news headlines, exposure to radiation is quickly becoming an issue of public, private, and government interest. Radiotherapy is a common treatment modality for cancer and other diseases. However, there are also equally clear hazards, such as the use of radioactive materials in acts of terrorism or war. Concomitant accidental or terrorism-related exposure to sublethal gamma or mixed-field (gamma and neutron) radiation would inevitably increase morbidity among individuals exposed to microbes. Ionizing radiation damages the haematopoietic and gastrointestinal systems. Prompt, sublethal irradiation increases the susceptibility to bacterial infections by decreasing the number of circulating mature white blood cells in the intestine. The data presented herein represent the first results exploring the effects of whole-body irradiation on the ability of the immune system to respond to microbes. We utilized γ-ray radiation as a model for radiation exposure and then challenged the animals 4 days postexposure to investigate the immune response in the most vulnerable phase of the hematopoietic-immune system. We employed Stapylococcus aureus bacterial challenges, a Gram-positive bacterium that is a major cause of septic shock and death

  4. Resistant and sensitive single-crystal diamond dosimeters for ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Trucchi, D.M., E-mail: daniele.trucchi@imip.cnr.it [CNR-IMIP, Via Salaria km 29.300, 00016 Monterotondo Scalo, Rome (Italy); Allegrini, P.; Bellucci, A.; Calvani, P. [CNR-IMIP, Via Salaria km 29.300, 00016 Monterotondo Scalo, Rome (Italy); Galbiati, A. [Solaris Photonics Ltd, 23 Almond Avenue, UB7 9 EL, London (United Kingdom); Girolami, M. [CNR-IFN, Via Cineto Romano 42, 00156 Rome (Italy)

    2013-08-01

    Diamond dosimeters for intense ionizing radiation were assembled by developing Ohmic contacts on single-crystal high-purity diamond films. Leakage electrical resistivity of the order of 10{sup 14} Ω cm was measured. Devices were tested with a low-intensity 17.48 keV X-ray beam to probe their maximum sensitivity and the minimum detectable dose-rate. Diamond detectors provided a linearity coefficient to X-ray dose-rate of 1.023±0.07, whose dependence on operative bias voltage is here analyzed.

  5. Sensitive detection of voids in solid materials by refraction-enhanced synchrotron radiation imaging

    International Nuclear Information System (INIS)

    Voids in opaque materials (minute air bubbles) were imaged with synchrotron radiation in a refraction enhancement mode. The voids are imaged by an enhanced x-ray intensity inside the bubble, surrounded by a border region with decreased x-ray intensity, thus allowing sensitive detection of air bubbles in plastic materials. As those 'impurities' could not be depicted with conventional radiography, and optical inspection is not useful if the matrix is opaque, this in-situ imaging technique offers the potential to obtain information of air inclusions, voids, and cracking that appear inadvertently in opaque plastics and possibly in metals as well

  6. MiR-224 expression increases radiation sensitivity of glioblastoma cells

    International Nuclear Information System (INIS)

    Highlights: • MiR-224 expression in established glioblastoma cell lines and sporadic tumor tissues is low. • Exogenous miR-224 expression was found to increase radiation sensitivity of glioblastoma cells. • MiR-224 expression brought about 55–60% reduction in API5 expression levels. • Transfection with API5 siRNA increased radiation sensitivity of glioblastoma cells. • Low miR-224 and high API5 expression correlated with worse survival of GBM patients. - Abstract: Glioblastoma (GBM) is the most common and highly aggressive primary malignant brain tumor. The intrinsic resistance of this brain tumor limits the efficacy of administered treatment like radiation therapy. In the present study, effect of miR-224 expression on growth characteristics of established GBM cell lines was analyzed. MiR-224 expression in the cell lines as well as in primary GBM tumor tissues was found to be low. Exogenous transient expression of miR-224 using either synthetic mimics or stable inducible expression using doxycycline inducible lentiviral vector carrying miR-224 gene, was found to bring about 30–55% reduction in clonogenic potential of U87 MG cells. MiR-224 expression reduced clonogenic potential of U87 MG cells by 85–90% on irradiation at a dose of 6 Gy, a dose that brought about 50% reduction in clonogenic potential in the absence of miR-224 expression. MiR-224 expression in glioblastoma cells resulted in 55–65% reduction in the expression levels of API5 gene, a known target of miR-224. Further, siRNA mediated down-regulation of API5 was also found to have radiation sensitizing effect on glioblastoma cell lines. Analysis of the Cancer Genome Atlas data showed lower miR-224 expression levels in male GBM patients to correlate with poorer survival. Higher expression levels of miR-224 target API5 also showed significant correlation with poorer survival of GBM patients. Up-regulation of miR-224 or down-regulation of its target API5 in combination with radiation therapy

  7. MiR-224 expression increases radiation sensitivity of glioblastoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Upraity, Shailendra; Kazi, Sadaf; Padul, Vijay; Shirsat, Neelam Vishwanath, E-mail: nshirsat@actrec.gov.in

    2014-05-30

    Highlights: • MiR-224 expression in established glioblastoma cell lines and sporadic tumor tissues is low. • Exogenous miR-224 expression was found to increase radiation sensitivity of glioblastoma cells. • MiR-224 expression brought about 55–60% reduction in API5 expression levels. • Transfection with API5 siRNA increased radiation sensitivity of glioblastoma cells. • Low miR-224 and high API5 expression correlated with worse survival of GBM patients. - Abstract: Glioblastoma (GBM) is the most common and highly aggressive primary malignant brain tumor. The intrinsic resistance of this brain tumor limits the efficacy of administered treatment like radiation therapy. In the present study, effect of miR-224 expression on growth characteristics of established GBM cell lines was analyzed. MiR-224 expression in the cell lines as well as in primary GBM tumor tissues was found to be low. Exogenous transient expression of miR-224 using either synthetic mimics or stable inducible expression using doxycycline inducible lentiviral vector carrying miR-224 gene, was found to bring about 30–55% reduction in clonogenic potential of U87 MG cells. MiR-224 expression reduced clonogenic potential of U87 MG cells by 85–90% on irradiation at a dose of 6 Gy, a dose that brought about 50% reduction in clonogenic potential in the absence of miR-224 expression. MiR-224 expression in glioblastoma cells resulted in 55–65% reduction in the expression levels of API5 gene, a known target of miR-224. Further, siRNA mediated down-regulation of API5 was also found to have radiation sensitizing effect on glioblastoma cell lines. Analysis of the Cancer Genome Atlas data showed lower miR-224 expression levels in male GBM patients to correlate with poorer survival. Higher expression levels of miR-224 target API5 also showed significant correlation with poorer survival of GBM patients. Up-regulation of miR-224 or down-regulation of its target API5 in combination with radiation therapy

  8. Radiation vulcanization of natural rubber latex using irradiation n-butyl acrylate aqueous emulsion as sensitizer

    International Nuclear Information System (INIS)

    Natural rubber latex was vulcanized by gamma radiation with n-butyl acrylate aqueous emulsion irradiated at dose of 1.5 kGy as sensitizer. The total solid content of latex increases on the irradiation dose. The viscosity of latex on the standing time was investigated and became stable after one month of storage. The gel content of latex films increasing with irradiation dose and attained more than 94% at dose of 10 kGy. Tensile strength of films reached the values of 31MPa; 30 Mpa and 25 Mpa at vulcanization doses of 20 kGy, 15 kGy and 8 kGy for the concentrations of sensitizer 7 phr, 9 phr and 13 phr respectively. Elongation at break decreases as increasing dose. Tear strength of rubber films was from 30-40 N/mm. The tackiness of latex films decreases and smell of vulcanized latex is almost negligible. (author)

  9. The effects of dimethylsulfoxide (DMSO) on the radiation sensitivity of bacterial spores

    International Nuclear Information System (INIS)

    Dimethylsufoxide (DMSO) is a potent sensitizer of irradiated bacterial spores (Bacillus megaterium). It is effective under either anoxic or well-oxygenated conditions; in both cases, DMSO increases the response by a factor of 3 to 4. In water, the oxygen enhancement ratio (OER) with 260-kVp X rays is 1.9, while in pure DMSO, which is not toxic to spores, the OER is reduced to 1.1. Spores exposed to DMSO and then washed and resuspended in water still show most of the DMSO-characteristic sensitization, even when the spores are soaked in water for 24 hr before irradiation. This effect is not attributable to DMSO retention by the spore; instead, we suggest that DMSO causes a long-lasting change in a critical spore component that changes the way the entire cell responds to radiation

  10. Radiation-induced DNA double-strand break frequencies in human squamous cell carcinoma cell lines of different radiation sensitivities

    International Nuclear Information System (INIS)

    DNA neutral (pH 9-6) filter elution was used to measure radiation-induced DNA double-strand break (dsb) frequencies in eight human squamous cell carcinoma cell lines with radiosensitivities (D0) ranging from 1.07 to 2.66 Gy and D-bar values ranging from 1.46 to 4.08 Gy. Elution profiles of unirradiated samples from more radiosensitive cell lines were all steeper in slope than profiles from resistant cells. The shapes of the dsb induction curves were curvilinear and there was some variability from cell line to cell line in the dose-response for the induction of DNA dsb after exposures to 5-100 Gy 60Co γ-rays. There was no relation between shapes of survival curves and shapes of the dose-responses for the induction of DNA dsb. At low doses (5-25 Gy), three out of four of the more sensitive cell lines (D-bar3.0 Gy). Although the low-dose (5-25 Gy) elution results were variable, they suggest that DNA neutral elution will detect differences between sensitive and resistant tumour cells in initial DNA dsb frequencies. (author)

  11. Radiation sensitivity of Salmonella isolates relative to resistance to ampicillin, chloramphenicol or gentamicin

    International Nuclear Information System (INIS)

    Antibiotic resistance of inoculated bacteria is a commonly used selective marker. Bacteria resistant to the antibiotic nalidixic acid have been shown to have an increased sensitivity to irradiation. The purpose of this research was to screen a collection of Salmonella isolates for antibiotic resistance and determine the association, if any, of antibiotic resistance with radiation sensitivity. Twenty-four clinical isolates of Salmonella were screened for native resistance to multiple concentrations of ampicillin (Amp), chloramphenicol (Chl), or gentamicin (Gm). Test concentrations were chosen based on established clinical minimum inhibitory concentration (MIC) levels, and isolates were classified as either sensitive or resistant based on their ability to grow at or above the MIC. Salmonella cultures were grown overnight at (37 oC) in antibiotic-amended tryptic soy broth (TSB). Native resistance to Gm was observed with each of the 24 isolates (100%). Eight isolates (33%) were shown to be resistant to Amp, while seven isolates (29%) were shown to be resistant to Chl. In separate experiments, Salmonella cultures were grown overnight (37 oC) in TSB, centrifuged, and the cell pellets were re-suspended in phosphate buffer. The samples were then gamma irradiated at doses up to 1.0 kGy. The D 10 values (the ionizing radiation dose required to reduce the viable number of microorganisms by 90%) were determined for the 24 isolates and they ranged from 0.181 to 0.359 kGy. No correlation was found between the D 10 value of the isolate and its sensitivity or resistance to each of the three antibiotics. Resistance to Amp or Chl is suggested as appropriate resistance marker for Salmonella test strains to be used in studies of irradiation

  12. Alteration of cytokine profiles in mice exposed to chronic low-dose ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Suk Chul [Radiation Health Research Institute, Korea Hydro and Nuclear Power Co., Ltd., 388-1, Ssangmun-dong, Dobong-gu, Seoul 132-703 (Korea, Republic of); Lee, Kyung-Mi [Global Research Lab, BAERI Institute, Department of Biochemistry and Molecular Biology, Korea University College of Medicine, Seoul 136-705 (Korea, Republic of); Kang, Yu Mi [Radiation Health Research Institute, Korea Hydro and Nuclear Power Co., Ltd., 388-1, Ssangmun-dong, Dobong-gu, Seoul 132-703 (Korea, Republic of); Kim, Kwanghee [Global Research Lab, BAERI Institute, Department of Biochemistry and Molecular Biology, Korea University College of Medicine, Seoul 136-705 (Korea, Republic of); Kim, Cha Soon; Yang, Kwang Hee; Jin, Young-Woo [Radiation Health Research Institute, Korea Hydro and Nuclear Power Co., Ltd., 388-1, Ssangmun-dong, Dobong-gu, Seoul 132-703 (Korea, Republic of); Kim, Chong Soon [Department of Nuclear Medicine, Haeundae Paik Hospital, Inje University, Busan 612-030 (Korea, Republic of); Kim, Hee Sun, E-mail: hskimdvm@khnp.co.kr [Radiation Health Research Institute, Korea Hydro and Nuclear Power Co., Ltd., 388-1, Ssangmun-dong, Dobong-gu, Seoul 132-703 (Korea, Republic of)

    2010-07-09

    While a high-dose of ionizing radiation is generally harmful and causes damage to living organisms, a low-dose of radiation has been shown to be beneficial in a variety of animal models. To understand the basis for the effect of low-dose radiation in vivo, we examined the cellular and immunological changes evoked in mice exposed to low-dose radiation at very low (0.7 mGy/h) and low (3.95 mGy/h) dose rate for the total dose of 0.2 and 2 Gy, respectively. Mice exposed to low-dose radiation, either at very low- or low-dose rate, demonstrated normal range of body weight and complete blood counts. Likewise, the number and percentage of peripheral lymphocyte populations, CD4{sup +} T, CD8{sup +} T, B, or NK cells, stayed unchanged following irradiation. Nonetheless, the sera from these mice exhibited elevated levels of IL-3, IL-4, leptin, MCP-1, MCP-5, MIP-1{alpha}, thrombopoietin, and VEGF along with slight reduction of IL-12p70, IL-13, IL-17, and IFN-{gamma}. This pattern of cytokine release suggests the stimulation of innate immunity facilitating myeloid differentiation and activation while suppressing pro-inflammatory responses and promoting differentiation of naive T cells into T-helper 2, not T-helper 1, types. Collectively, our data highlight the subtle changes of cytokine milieu by chronic low-dose {gamma}-radiation, which may be associated with the functional benefits observed in various experimental models.

  13. Alteration of cytokine profiles in mice exposed to chronic low-dose ionizing radiation

    International Nuclear Information System (INIS)

    While a high-dose of ionizing radiation is generally harmful and causes damage to living organisms, a low-dose of radiation has been shown to be beneficial in a variety of animal models. To understand the basis for the effect of low-dose radiation in vivo, we examined the cellular and immunological changes evoked in mice exposed to low-dose radiation at very low (0.7 mGy/h) and low (3.95 mGy/h) dose rate for the total dose of 0.2 and 2 Gy, respectively. Mice exposed to low-dose radiation, either at very low- or low-dose rate, demonstrated normal range of body weight and complete blood counts. Likewise, the number and percentage of peripheral lymphocyte populations, CD4+ T, CD8+ T, B, or NK cells, stayed unchanged following irradiation. Nonetheless, the sera from these mice exhibited elevated levels of IL-3, IL-4, leptin, MCP-1, MCP-5, MIP-1α, thrombopoietin, and VEGF along with slight reduction of IL-12p70, IL-13, IL-17, and IFN-γ. This pattern of cytokine release suggests the stimulation of innate immunity facilitating myeloid differentiation and activation while suppressing pro-inflammatory responses and promoting differentiation of naive T cells into T-helper 2, not T-helper 1, types. Collectively, our data highlight the subtle changes of cytokine milieu by chronic low-dose γ-radiation, which may be associated with the functional benefits observed in various experimental models.

  14. On high-frequency radiation scattering sensitivity to surface roughness in particulate media

    Science.gov (United States)

    Zohdi, T. I.

    2016-06-01

    This paper analyzes the sensitivity of high-frequency radiation scattering in particulate media, to particle surface roughness. Ray-tracing theory and computation are employed. Since the magnitude of the Poynting vector ray, the irradiance, is the appropriate quantity to be tracked, the behavior of the reflectance, which controls the ratio of the reflected and incident Poynting vector magnitudes, is of primary concern. The reflectance is a highly nonlinear function of the refractive indices and angle of incidence. The present work first addresses the relationship between a single scatterer's sensitivity to its surface roughness and then the response of a large number of scatterers to the surface roughness. The analysis indicates that, for a single scatterer, the sensitivity of the response to roughness decreases, up to a point, and then increases again, i.e., it is nonmonotone. However, for a system of multiple scatterers, this effect vanishes, due to multiple internal reflections which dominate the overall response characteristics. While it was relatively straightforward to compute the overall sensitivity of a single scattering body, for example a sphere, when multiple reflecting bodies are considered, numerical simulations are necessary because the reflected rays from one "rough" body will, in turn, be reflected to another "rough" body, etc. Examples are given for a system of randomly distributed scatterers.

  15. Female Flinders Sensitive Line rats show estrous cycle-independent depression-like behavior and altered tryptophan metabolism.

    Science.gov (United States)

    Eskelund, Amanda; Budac, David P; Sanchez, Connie; Elfving, Betina; Wegener, Gregers

    2016-08-01

    Clinical studies suggest a link between depression and dysfunctional tryptophan (TRP) metabolism. Even though depression is twice as prevalent in women as men, the impact of the estrous cycle on TRP metabolism is not well-understood. Here we investigated 13 kynurenine and serotonin metabolites in female Flinders Sensitive Line (FSL) rats, a genetic rat model of depression. FSL rats and controls (Flinders Resistant Line rats), 12-20weeks old, were subject to the forced swim test (FST), a commonly used measure of depression-like behavior. Open field was used to evaluate locomotor ability and agoraphobia. Subsequently, plasma and hemispheres were collected and analyzed for their content of TRP metabolites using liquid chromatography-tandem mass spectrometry. Vaginal saline lavages were obtained daily for ⩾2 cycles. To estimate the effects of sex and FST we included plasma from unhandled, naïve male FSL and FRL rats. Female FSL rats showed a depression-like phenotype with increased immobility in the FST, not confounded by anxiety. In the brain, 3-hydroxykynurenine was increased whereas anthranilate and 5-hydroxytryptophan were decreased. In plasma, anthranilate and quinolinate levels were lower in FSL rats compared to the control line, independent of sex and FST. The estrous cycle neither impacted behavior nor TRP metabolite levels in the FSL rat. In conclusion, the female FSL rat is an interesting preclinical model of depression with altered TRP metabolism, independent of the estrous cycle. The status of the pathway in brain was not reflected in the plasma, which may indicate that an inherent local, cerebral regulation of TRP metabolism occurs. PMID:27210075

  16. Alterations of mtDNA number and 4977 bp deletion induced by ionizing radiation in human peripheral blood

    International Nuclear Information System (INIS)

    Alterations of mitochondria DNA (mtDNA) 4977 bp common deletion (CD) and mtDNA copy number induced by ionizing radiation were observed in human different cell lines and total body irradiation patients. However, only few experiments have evaluated the levels of the CD and mtDNA copy number in human peripheral blood exposed to ionizing radiation till now. The aim of this study is to analyze the mtDNA alterations in irradiated human peripheral blood from healthy donors as well as to explore their feasibility as biomarkers for constructing new biodosimeter. Peripheral blood samples were collected from six healthy donors, and exposed to 60Co gamma ray with the doses of 0 Gy, 1 Gy, 2 Gy, 3 Gy, 4 Gy and 5 Gy. Levels of the CD and mtDNA copy number in irradiated samples after 2h or 24 h incubation were detected using TaqMan real-time PCR, and the CD ratio was calculated. The results showed that the mean of the CD ratio and the CD copy number exhibited a dose-dependent increase 2 h in the dose range from 0-5 Gy, and of the mtDNA copy number significantly increased 24 h in irradiated groups compared with 0 Gy group after irradiation. It indicates that the parameters in human peripheral blood may be considered as molecular biomarkers to applying construction of new biodosimeter. (authors)

  17. Molecular alterations in tumorigenic human breast epithelial cells transformed by high LET radiation

    International Nuclear Information System (INIS)

    Full text: Carcinogenesis is a multi-stage process with sequences of genetic events governing the phenotypic expression of a series of transformation steps leading to the development of metastatic cancer. In the present study, spontaneously-immortalized human breast (MCF-10F) cells were irradiated with graded doses of 150 keV/μm alpha particles. Transformed cells developed through a series of successive steps before becoming tumorigenic in nude mice and estrogen was found to be essential to the neoplastic process. The differential expressions of known genes between tumorigenic breast cells induced by alpha particles and their respective control cultures were compared using cDNA expression array. Seven genes including the transforming protein RhoA and the oncogene fgr were found to be specifically altered among tumorigenic breast epithelial cells. Using microsatellite markers located on human chromosome 6, 11, and 17 that are frequently found to be altered in human breast cancers, a progressive degree of allelic imbalance of up to 50% was detected at the chromosome locations examined. The results are highly suggestive that functional alterations of these genes/ chromosomal locales may be causally related to the carcinogenic process

  18. Synergistic effects of ultraviolet radiation, thermal cycling and atomic oxygen on altered and coated Kapton surfaces

    Science.gov (United States)

    Dever, Joyce A.; Bruckner, Eric J.; Rodriguez, Elvin

    1992-01-01

    The photovoltaic (PV) power system for Space Station Freedom (SSF) uses solar array blankets which provide structural support for the solar cells and house the electrical interconnections. In the low earth orbital (LEO) environment where SSF will be located, surfaces will be exposed to potentially damaging environmental conditions including solar ultraviolet (UV) radiation, thermal cycling, and atomic oxygen. It is necessary to use ground based tests to determine how these environmental conditions would affect the mass loss and optical properties of candidate SSF blanket materials. Silicone containing, silicone coated, and SiO(x) coated polyimide film materials were exposed to simulated LEO environmental conditions to determine their durability and whether the environmental conditions of UV, thermal cycling and oxygen atoms act synergistically on these materials. A candidate PV blanket material called AOR Kapton, a polysiloxane polyimide cast from a solution mixture, shows an improvement in durability to oxygen atoms erosion after exposure to UV radiation or thermal cycling combined with UV radiation. This may indicate that the environmental conditions react synergistically with this material, and the damage predicted by exposure to atomic oxygen alone is more severe than that which would occur in LEO where atomic oxygen, thermal cycling and UV radiation are present together.

  19. Radiation-induced apoptosis of stem/progenitor cells in human umbilical cord blood is associated with alterations in reactive oxygen and intracellular pH

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Tomonori [Department of Radiobiology/Molecular Epidemiology, Radiation Effects Research Foundation, Hijyama Park, Minami Ward, Hiroshima (Japan)]. E-mail: tomo@rerf.or.jp; Hayashi, Ikue [Central Research Laboratory, Hiroshima University Faculty of Dentistry, Hiroshima (Japan); Shinohara, Tomoko [Department of Radiobiology/Molecular Epidemiology, Radiation Effects Research Foundation, Hijyama Park, Minami Ward, Hiroshima (Japan); Morishita, Yukari [Department of Radiobiology/Molecular Epidemiology, Radiation Effects Research Foundation, Hijyama Park, Minami Ward, Hiroshima (Japan); Nagamura, Hiroko [Department of Radiobiology/Molecular Epidemiology, Radiation Effects Research Foundation, Hijyama Park, Minami Ward, Hiroshima (Japan); Kusunoki, Yoichiro [Department of Radiobiology/Molecular Epidemiology, Radiation Effects Research Foundation, Hijyama Park, Minami Ward, Hiroshima (Japan); Kyoizumi, Seishi [Department of Radiobiology/Molecular Epidemiology, Radiation Effects Research Foundation, Hijyama Park, Minami Ward, Hiroshima (Japan); Seyama, Toshio [Yasuda Women' s University, Hiroshima (Japan); Nakachi, Kei [Department of Radiobiology/Molecular Epidemiology, Radiation Effects Research Foundation, Hijyama Park, Minami Ward, Hiroshima (Japan)

    2004-11-22

    To investigate the sensitivity of human hematopoietic stem cell populations to radiation and its relevance to intracellular events, specifically alteration in cellular energy production systems, we examined the frequency of apoptotic cells, generation of superoxide anions (O2-), and changes in cytosol pH in umbilical cord blood (UCB) CD34{sup +}/CD38{sup -}, CD34{sup +}/CD38{sup +} and CD34{sup -}/CD38{sup +} cells before and after 5Gy of X-irradiation. Human UCB mononucleated cells were used in this study. After X-irradiation and staining subgroups of the cells with fluorescence (FITC, PE, or CY)-labeled anti-CD34 and anti-CD38 antibodies, analyses were performed by FACScan using as stains 7-amino-actinomycin D (7-AAD) for the detection of apoptosis, and hydroethidine (HE) for the measurement of O2- generation in the cells. For intracellular pH, image analysis was conducted using confocal laser microscopy after irradiation and staining with carboxy-SNAFR-1. The frequency of apoptotic cells, as determined by cell staining with 7-AAD, was highest in the irradiated CD34{sup +}/CD38{sup -} cell population, where the level of O2- detected by the oxidation of HE was also most highly elevated. Intracellular pH measured with carboxy-SNARF-1-AM by image cytometer appeared to be lowest in the same irradiated CD34{sup +}/CD38{sup -} cell population, and this intracellular pH decreased as early as 4h post-irradiation, virtually simultaneous with the significant elevation of O2- generation. These results suggest that the CD34{sup +}/CD38{sup -} stem cell population is sensitive to radiation-induced apoptosis as well as production of intracellular O2-, compare to more differentiated CD34{sup +}/CD38{sup +} and CD34{sup -}/CD38{sup +} cells and that its intracellular pH declines at an early phase in the apoptosis process.

  20. Position-sensitive radiation monitoring (surface contamination monitor). Innovative technology summary report

    Energy Technology Data Exchange (ETDEWEB)

    1999-06-01

    The Shonka Research Associates, Inc. Position-Sensitive Radiation Monitor both detects surface radiation and prepares electronic survey map/survey report of surveyed area automatically. The electronically recorded map can be downloaded to a personal computer for review and a map/report can be generated for inclusion in work packages. Switching from beta-gamma detection to alpha detection is relatively simple and entails moving a switch position to alpha and adjusting the voltage level to an alpha detection level. No field calibration is required when switching from beta-gamma to alpha detection. The system can be used for free-release surveys because it meets the federal detection level sensitivity limits requires for surface survey instrumentation. This technology is superior to traditionally-used floor contamination monitor (FCM) and hand-held survey instrumentation because it can precisely register locations of radioactivity and accurately correlate contamination levels to specific locations. Additionally, it can collect and store continuous radiological data in database format, which can be used to produce real-time imagery as well as automated graphics of survey data. Its flexible design can accommodate a variety of detectors. The cost of the innovative technology is 13% to 57% lower than traditional methods. This technology is suited for radiological surveys of flat surfaces at US Department of Energy (DOE) nuclear facility decontamination and decommissioning (D and D) sites or similar public or commercial sites.

  1. Radiation sensitivity of foodborne pathogens in meat byproducts with different packaging

    International Nuclear Information System (INIS)

    The aim of this study was to determine radiation sensitivity of Escherichia coli O157:H7 and Listeria monocytogenes in edible meat byproducts. Seven beef byproducts (heart, liver, lung, lumen, omasum, large intestine, and small intestine) and four pork byproducts (heart, large intestine, liver, and small intestine) were used. Electron beam irradiation significantly reduced the numbers of pathogenic microorganisms in meat byproducts and no viable cells were detected in both aerobically- and vacuum-packaged samples irradiated at 4 kGy. Meat byproducts packed under vacuum had higher D10 value than the ones packed aerobically. No significant difference was observed between the D10 values of E. coli O157:H7 and L. monocytogenes inoculated in either aerobically or vacuum packaged samples. These results suggest that low-dose electron beam irradiation can significantly decrease microbial numbers and reduce the risk of meat byproduct contamination by the foodborne pathogens. - Highlights: • Radiation sensitivities of pathogens in meat byproduct were tested. • Electron beam irradiation of 3 or 4 kGy reduced pathogens by> 9 log • The D10 values were lower in the aerobic-packaging than under vacuum condition

  2. Sensitivity of radiation monitoring systems in Manila Ports in detecting contamination in foodstuff shipments

    International Nuclear Information System (INIS)

    During the Fukushima Nuclear Power Plant accident in Japan, one of the Philippines' measures to protect the public from radiological hazards of the accident is by monitoring agricultural and food imports for radioactive contamination. In this study, the sensitivity of the mobile Radiation Monitoring System (RM) in Manila Ports in detecting contamination in incoming foodstuff shipments was determined. Large volume synthetic 137Cs reference sources were used to determine the minimum detectable concentration (MDC) of the RMS. The reference sources have radioactivity concentrations that are comparable to the PNRI guidance level of 1000 Bg/kg for 137Cs that is destined for general consumption. Results of the MDC measurements show that the RMS units are sensitive enough to detect radioactivity levels that are within the guidance levels provided that a) the minimum package lot is approximately 200 kg, b) the package is positioned at the detector side, and c) the alarm setting of RMS is as calibrated. It was therefore established that the RMS can be used to initially screen incoming foodstuff shipments of possible contamination and thereby help minimize potential radiation exposures to the public. (author)

  3. Estimations of climate sensitivity based on top-of-atmosphere radiation imbalance

    Directory of Open Access Journals (Sweden)

    B. Lin

    2010-02-01

    Full Text Available Large climate feedback uncertainties limit the accuracy in predicting the response of the Earth's climate to the increase of CO2 concentration within the atmosphere. This study explores a potential to reduce uncertainties in climate sensitivity estimations using energy balance analysis, especially top-of-atmosphere (TOA radiation imbalance. The time-scales studied generally cover from decade to century, that is, middle-range climate sensitivity is considered, which is directly related to the climate issue caused by atmospheric CO2 change. The significant difference between current analysis and previous energy balance models is that the current study targets at the boundary condition problem instead of solving the initial condition problem. Additionally, climate system memory and deep ocean heat transport are considered. The climate feedbacks are obtained based on the constraints of the TOA radiation imbalance and surface temperature measurements of the present climate. In this study, the TOA imbalance value of 0.85 W/m2 is used. Note that this imbalance value has large uncertainties. Based on this value, a positive climate feedback with a feedback coefficient ranging from −1.3 to −1.0 W/m2/K is found. The range of feedback coefficient is determined by climate system memory. The longer the memory, the stronger the positive feedback. The estimated time constant of the climate is large (70~120 years mainly owing to the deep ocean heat transport, implying that the system may be not in an equilibrium state under the external forcing during the industrial era. For the doubled-CO2 climate (or 3.7 W/m2 forcing, the estimated global warming would be 3.1 K if the current estimate of 0.85 W/m2 TOA net radiative heating could be confirmed. With accurate long-term measurements of TOA radiation, the analysis method suggested by this study provides a great potential in the

  4. Estimating option values of solar radiation management assuming that climate sensitivity is uncertain.

    Science.gov (United States)

    Arino, Yosuke; Akimoto, Keigo; Sano, Fuminori; Homma, Takashi; Oda, Junichiro; Tomoda, Toshimasa

    2016-05-24

    Although solar radiation management (SRM) might play a role as an emergency geoengineering measure, its potential risks remain uncertain, and hence there are ethical and governance issues in the face of SRM's actual deployment. By using an integrated assessment model, we first present one possible methodology for evaluating the value arising from retaining an SRM option given the uncertainty of climate sensitivity, and also examine sensitivities of the option value to SRM's side effects (damages). Reflecting the governance challenges on immediate SRM deployment, we assume scenarios in which SRM could only be deployed with a limited degree of cooling (0.5 °C) only after 2050, when climate sensitivity uncertainty is assumed to be resolved and only when the sensitivity is found to be high (T2x = 4 °C). We conduct a cost-effectiveness analysis with constraining temperature rise as the objective. The SRM option value is originated from its rapid cooling capability that would alleviate the mitigation requirement under climate sensitivity uncertainty and thereby reduce mitigation costs. According to our estimates, the option value during 1990-2049 for a +2.4 °C target (the lowest temperature target level for which there were feasible solutions in this model study) relative to preindustrial levels were in the range between $2.5 and $5.9 trillion, taking into account the maximum level of side effects shown in the existing literature. The result indicates that lower limits of the option values for temperature targets below +2.4 °C would be greater than $2.5 trillion. PMID:27162346

  5. Binary sensitive systems based on A-ProOMe/AAc synthesized by gamma radiation

    International Nuclear Information System (INIS)

    Complete text of publication follows. Thermo and pH-responsive gels have received much interest in different fields of knowledge for their applications in drug delivery systems, controlled release systems for targeted delivery to specific areas of body and others. Poly(acryloyl-L-proline methyl ester) (A-ProOMe) exhibits a lower critical temperature (LCST) of 14 deg C and polyacrylic acid (PAAc) exhibits a critical pH response at about 4.5 deg C. In this work, three different systems containing (A-ProOMe) and (PAAc) were synthesized by gamma radiation; a) A-ProOMe grafted onto PAAc hydrogel 'comb type hydrogel'; b) radiation binary grafting of A-ProOMe and AAc onto PP by mutual irradiation method PP-g-AAc/A-ProOMe; and c) and binary grafting of those monomers in two step radiation method (PP-g- AAc)-g-(A-ProOMe). The characterization of the graft copolymers was examined by infrared (FTIR-ATR), and thermal analysis (TGA). Limit swelling behavior, pH sensitivity and Cu+2 uptake of different systems will be discussed. The authors wish to express their thanks to S. Castillo-Rojas, B. Leal, F. Garcia, and M. Cruz, from ICN-UNAM, for technical assistance. This work was supported by DGAPA-UNAM Mexico, Grant IN200108.

  6. Etoposide sensitizes CT26 colorectal adenocarcinoma to radiation therapy in BALB/c mice

    Institute of Scientific and Technical Information of China (English)

    Chia-Yuan Liu; Hui-Fen Liao; Tsang-En Wang; Shee-Chan Lin; Shou-Chuan Shih; Wen-Hsuing Chang; Yuh-Cheng Yang; Ching-Chung Lin; Yu-Jen Chen

    2005-01-01

    AIM: To investigate the combined effect of etoposide and radiation on CT26 colorectal adenocarcinoma implanted into BALB/c mice.METHODS: We evaluated the radiosensitizing effect of etoposide on CT26 colorectal adenocarcinoma in a syngeneic animal model. BALB/c mice were subcutaneously implanted with CT26 cells and divided into four groups:control (intra-peritoneal salinex2) group, etoposide (5 mg/kgintra-peritoneallyx2) group, radiation therapy (RT 5 Gyx2fractions) group, and combination therapy with etoposide (5 mg/kg intra-peritoneally 1 h before radiation) group.RESULTS: Tumor growth was significantly inhibited by RT and combination therapy. The effect of combination therapy was better than that of RT. No significant changes were noted in body weight, plasma alanine aminotransferase,or creatinine in any group. The leukocyte count significantly but transiently decreased in the RT and combination therapy groups, but not in the etoposide and control groups. There was no skin change or hair loss in the RT and combination therapy groups.CONCLUSION: Etoposide can sensitize CT26 colorectal adenocarcinoma in BALB/c mice to RT without significant toxicity.

  7. Involvement of protease activation in modulating radiation-sensitivity of human cells

    International Nuclear Information System (INIS)

    Molecular mechanisms that supervise radiation-susceptibility of human cells are one of the important problems in molecular biology. We previously hypothesized that proteases may play a key role in cellular functions triggered by radiation as well as those in SOS functions of E. coli. We describe proteases activity induced immediately after UV (254-nm wavelength ultraviolet ray) and X-ray irradiation of cultured human cells. The activity was estimated by reaction in vitro, using enzyme preparations of cell lysates and 125I-fibrin as a substrate in the presence of plasminogen. Based on the previous findings that the activity of UV-induced proteases is specifically inhibited by antipain and enhanced by interferons, partial purification was performed, revealing a single activity peak of approximate 20 kDa on gel filtration chromatography. This activity seemed to be involved in the radio-resistance of cells against UV, because the activation correlated with increased resistance of cells to UV cell-killing. Moreover, the activation was also observed in association with hypomutable change of cells mutagenized with ethylmethanesulfonate and cells pretreated with human interferons prior to UV irradiation, when UV-induced mutagenicity was estimated by detection of K-ras codon 12 mutations. However, human RSa cells, with high sensitivity to cell-killing and mutagenicity of X-ray, showed increased levels of proteases activity immediately after X-ray irradiation. Therefore, it seems likely that proteases are activated by different ionizing or non-ionizing radiation, and that the proteases may play radio -sensitive or -protective roles in human cells. (author)

  8. Sensitivity of human cells defective of DNA repair enzyme genes to radiation and medical agents

    International Nuclear Information System (INIS)

    Homologous recombination and non-homologous end-joining (NHEJ) are the known mechanisms of repairing DNA with double strand break (DSB) yielded by radiation and cell-cycle independent NHEJ is thought to be major in higher eukaryotes. Recognized now are 7 proteins like Artemis and XRCC4 concerned in NHEJ, but little is known for functions of those proteins in human cells. Authors have developed a method to destroy the specific gene by targeting for the study of the responses to DNA damage in human Artemis-/- and XRCC4-/- cells, which is described in this paper. Parent cell strain is a human colorectal cancer-derived epithelial HCT116, and those defective cells are obtained by targeting with puromycin and neomycin resistant vectors. Their sensitivities to X-ray (0.6 Gy/min), to etoposide and to other anti-cancers are examined by survival vs dose; and the relationship between the sensitivity to damaged DNA stress and DSB production is tested by chromosome aberration frequency and by γH22AX focus formation (a measure of DSB yield) after X-exposure. Results obtained show the important role of Artemis and XRCC4 also in human cell DSB response. With reactive oxygen species (H2O2), those cells are further used in similar experiments to above, which suggesting a different mechanism of DSB induction by H2O2 from that by radiation. Other genes than the two here in NHEJ will be investigated in future with gene targeting techniques for systematic, molecular elucidation of radiation effects in humans. (K.T.)

  9. Mechanism of misonidazole linked cytotoxicity and altered radiation response: role of cellular thiols

    International Nuclear Information System (INIS)

    The effectiveness of misonidazole as a hypoxic radiosensitizer of mammalian cells is increased by prolonged exposure of hypoxic cells to the drug. It was found that drug intermediates might react with endogenous non-protein thiols (NPSH). These thiols function to protect the cell against deleterious intermediates that could otherwise attach and modify critical macromolecules such as DNA, RNA and protein. This paper presents studies on the effects of misonidazole, as well as newly developed hypoxic cell radiosensitizers, in an attempt to (1) identify the alterations in the NPSH, and (2) elucidate the role that the changes in NPSH play in cytotoxic and radiosensitizing effects of nitro compounds

  10. Low-level red laser therapy alters effects of ultraviolet C radiation on Escherichia coli cells

    Directory of Open Access Journals (Sweden)

    K.S. Canuto

    2015-01-01

    Full Text Available Low-level lasers are used at low power densities and doses according to clinical protocols supplied with laser devices or based on professional practice. Although use of these lasers is increasing in many countries, the molecular mechanisms involved in effects of low-level lasers, mainly on DNA, are controversial. In this study, we evaluated the effects of low-level red lasers on survival, filamentation, and morphology of Escherichia coli cells that were exposed to ultraviolet C (UVC radiation. Exponential and stationary wild-type and uvrA-deficient E. coli cells were exposed to a low-level red laser and in sequence to UVC radiation. Bacterial survival was evaluated to determine the laser protection factor (ratio between the number of viable cells after exposure to the red laser and UVC and the number of viable cells after exposure to UVC. Bacterial filaments were counted to obtain the percentage of filamentation. Area-perimeter ratios were calculated for evaluation of cellular morphology. Experiments were carried out in duplicate and the results are reported as the means of three independent assays. Pre-exposure to a red laser protected wild-type and uvrA-deficient E. coli cells against the lethal effect of UVC radiation, and increased the percentage of filamentation and the area-perimeter ratio, depending on UVC fluence and physiological conditions in the cells. Therapeutic, low-level red laser radiation can induce DNA lesions at a sub-lethal level. Consequences to cells and tissues should be considered when clinical protocols based on this laser are carried out.

  11. Low-level red laser therapy alters effects of ultraviolet C radiation on Escherichia coli cells

    International Nuclear Information System (INIS)

    Low-level lasers are used at low power densities and doses according to clinical protocols supplied with laser devices or based on professional practice. Although use of these lasers is increasing in many countries, the molecular mechanisms involved in effects of low-level lasers, mainly on DNA, are controversial. In this study, we evaluated the effects of low-level red lasers on survival, filamentation, and morphology of Escherichia coli cells that were exposed to ultraviolet C (UVC) radiation. Exponential and stationary wild-type and uvrA-deficient E. coli cells were exposed to a low-level red laser and in sequence to UVC radiation. Bacterial survival was evaluated to determine the laser protection factor (ratio between the number of viable cells after exposure to the red laser and UVC and the number of viable cells after exposure to UVC). Bacterial filaments were counted to obtain the percentage of filamentation. Area-perimeter ratios were calculated for evaluation of cellular morphology. Experiments were carried out in duplicate and the results are reported as the means of three independent assays. Pre-exposure to a red laser protected wild-type and uvrA-deficient E. coli cells against the lethal effect of UVC radiation, and increased the percentage of filamentation and the area-perimeter ratio, depending on UVC fluence and physiological conditions in the cells. Therapeutic, low-level red laser radiation can induce DNA lesions at a sub-lethal level. Consequences to cells and tissues should be considered when clinical protocols based on this laser are carried out. (author)

  12. Low-level red laser therapy alters effects of ultraviolet C radiation on Escherichia coli cells

    Energy Technology Data Exchange (ETDEWEB)

    Canuto, K.S.; Guimaraes, O.R.; Geller, M. [Centro Universitario Serra dos Orgaos, Teresopolis, RJ (Brazil). Centro de Ciencias da Saude; Sergio, L.P.S. [Instituto de Biologia Roberto Alcantara Gomes, Rio de Janeiro, RJ (Brazil). Departamento de Biofisica e Biometria; Paoli, F. [Universidade Federal de Juiz de Fora (UFJF), Juiz de Fora, MG (Brazil). Departamento de Morfologia; Fonseca, A.S., E-mail: adnfonseca@ig.com.br [Universidade Federal do Estado do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Departamento de Ciencias Fisiologicas

    2015-10-15

    Low-level lasers are used at low power densities and doses according to clinical protocols supplied with laser devices or based on professional practice. Although use of these lasers is increasing in many countries, the molecular mechanisms involved in effects of low-level lasers, mainly on DNA, are controversial. In this study, we evaluated the effects of low-level red lasers on survival, filamentation, and morphology of Escherichia coli cells that were exposed to ultraviolet C (UVC) radiation. Exponential and stationary wild-type and uvrA-deficient E. coli cells were exposed to a low-level red laser and in sequence to UVC radiation. Bacterial survival was evaluated to determine the laser protection factor (ratio between the number of viable cells after exposure to the red laser and UVC and the number of viable cells after exposure to UVC). Bacterial filaments were counted to obtain the percentage of filamentation. Area-perimeter ratios were calculated for evaluation of cellular morphology. Experiments were carried out in duplicate and the results are reported as the means of three independent assays. Pre-exposure to a red laser protected wild-type and uvrA-deficient E. coli cells against the lethal effect of UVC radiation, and increased the percentage of filamentation and the area-perimeter ratio, depending on UVC fluence and physiological conditions in the cells. Therapeutic, low-level red laser radiation can induce DNA lesions at a sub-lethal level. Consequences to cells and tissues should be considered when clinical protocols based on this laser are carried out. (author)

  13. Electromagnetic Energy Radiated from Mobile Phone Alters Electrocardiographic Records of Patients with Ischemic Heart Disease

    OpenAIRE

    Alhusseiny, AH; Al-Nimer, MS; Majeed, AD

    2012-01-01

    Background: Electromagnetic energy radiated from mobile phones did not show significant effect on the blood pressure, heart rate, and electrocardiographic (ECG) parameters in animals and humans. Aim: This study aimed to investigate the effect of radiofrequency of mobile phone on the electrocardiographic parameters in patients with history of ischemic heart disease, taking into consideration the gender factor. Subjects and Methods: A total number of 356 participants (129 males and 227 females)...

  14. Ground-based microgravity and proton radiation exposure alters leukocyte activity

    OpenAIRE

    Sanzari, Jenine K.; Romero-Weaver, Ana; Krigsfeld, Gabriel S.; James, Gabrielle; Lin, Liyong; Diffenderfer, Eric S.; Kennedy, Ann R.

    2014-01-01

    Immune system adaptation during spaceflight is a concern in space medicine. Decreased circulating leukocytes observed during and after space flight infer suppressed immune responses and susceptibility to infection. The microgravity aspect of the space environment has been simulated on Earth to study adverse biological effects in astronauts. In this report, the hindlimb unloading (HU) model was employed to investigate the combined effects of solar particle event-like proton radiation and simul...

  15. Leukocyte Activity Is Altered in a Ground Based Murine Model of Microgravity and Proton Radiation Exposure

    OpenAIRE

    Sanzari, Jenine K.; Romero-Weaver, Ana L.; James, Gabrielle; Krigsfeld, Gabriel; Lin, Liyong; Diffenderfer, Eric S.; Kennedy, Ann R.

    2013-01-01

    Immune system adaptation during spaceflight is a concern in space medicine. Decreased circulating leukocytes observed during and after space flight infer suppressed immune responses and susceptibility to infection. The microgravity aspect of the space environment has been simulated on Earth to study adverse biological effects in astronauts. In this report, the hindlimb unloading (HU) model was employed to investigate the combined effects of solar particle event-like proton radiation and simul...

  16. Radioprotective potential of Emblica officinalis fruit extract against hematological alterations induced by gamma radiation

    International Nuclear Information System (INIS)

    In the era of expending nuclear energy program all over the world, the role of radiation biology has acquired greater relevance and significance in addressing the health issues in view of constant human exposure to various types of radiations. Radioprotective drugs hold immense promise for saving precious human lives in from irradiation in various situations. Currently available synthetic radiomudulators is fraught with their inherent toxicity at the optimum dose and hence the need to discover and develop new more effective less toxic radiomudulatory drugs from natural sources. In the present study, the protective effect of Emblica officinalis fruit extract (EOFE) has been assessed by estimating hematological constituents against irradiation. For this purpose, Swiss albino mice were divided into four groups. Group I was administered with double distilled water (DDW) volume equal to EOFE (100 mg./kg. body wt./animal/clay) by oral gavages to serve as normal. Group II was administered orally EOFE for 7 days once daily at a does of 100 mg./kg.b. wt./animal/day, Group Ill animals were exposed to 2.5 Gy gamma radiations to serve as irradiated control. Group IV mice were treated with EOFE, orally for consecutive days (as in Group II) and were exposed to 2.5 Gy gamma rays half an hr. after the last administration of EOFE on day 7th. The above animals were necropsied on 12 hr, 24 hr, 3 days, 5 days, 10 days, 20 days and 30 days post treatment intervals, and their blood was collected for estimation of blood constituents. A significant decline in RBC, hemoglobin (Hb) and hematocrit (Hct) contents from normal was observed in irradiated control animals (Group III). All these parameters were found to be significantly higher in EOFE pretreated irradiated animals (Group IV). From these results, it is concluded that Emblica officinalis fruit extract has the ability to protect the individuals from radiation-induced hematological injuries. (author)

  17. Enhanced radiation sensitivity and radiation recall dermatitis (RRD after hypericin therapy – case report and review of literature

    Directory of Open Access Journals (Sweden)

    Schäfer Christof

    2006-09-01

    Full Text Available Abstract Background Modern radiotherapy (RT reduces the side effects at organ at risk. However, skin toxicity is still a major problem in many entities, especially head and neck cancer. Some substances like chemotherapy provide a risk of increased side effects or can induce a "recall phenomenon" imitating acute RT-reactions months after RT. Moreover, some phototoxic drugs seem to enhance side effects of radiotherapy while others do not. We report a case of "radiation recall dermatitis" (RRD one year after RT as a result of taking hypericin (St. John's wort. Case report A 65 year old man with completely resected squamous cell carcinoma of the epiglottis received an adjuvant locoregional RT up to a dose of 64.8 Gy. The patient took hypericin during and months after RT without informing the physician. During radiotherapy the patient developed unusual intensive skin reactions. Five months after RT the skin was completely bland at the first follow up. However, half a year later the patient presented erythema, but only within the area of previously irradiated skin. After local application of a steroid cream the symptoms diminished but returned after the end of steroid therapy. The anamnesis disclosed that the patient took hypericin because of depressive mood. We recommended to discontinue hypericin and the symptoms disappeared afterward. Conclusion Several drugs are able to enhance skin toxicity of RT. Furthermore, the effect of RRD is well known especially for chemotherapy agents such as taxans. However, the underlying mechanisms are not known in detail so far. Moreover, it is unknown whether photosensitising drugs can also be considered to increase radiation sensitivity and whether a recall phenomenon is possible. The first report of a hypericin induced RRD and review of the literature are presented. In clinical practise many interactions between drugs and radiotherapy were not noticed and if registered not published. We recommend to ask especially

  18. Enhanced radiation sensitivity and radiation recall dermatitis (RRD) after hypericin therapy – case report and review of literature

    International Nuclear Information System (INIS)

    Modern radiotherapy (RT) reduces the side effects at organ at risk. However, skin toxicity is still a major problem in many entities, especially head and neck cancer. Some substances like chemotherapy provide a risk of increased side effects or can induce a 'recall phenomenon' imitating acute RT-reactions months after RT. Moreover, some phototoxic drugs seem to enhance side effects of radiotherapy while others do not. We report a case of 'radiation recall dermatitis' (RRD) one year after RT as a result of taking hypericin (St. John's wort). A 65 year old man with completely resected squamous cell carcinoma of the epiglottis received an adjuvant locoregional RT up to a dose of 64.8 Gy. The patient took hypericin during and months after RT without informing the physician. During radiotherapy the patient developed unusual intensive skin reactions. Five months after RT the skin was completely bland at the first follow up. However, half a year later the patient presented erythema, but only within the area of previously irradiated skin. After local application of a steroid cream the symptoms diminished but returned after the end of steroid therapy. The anamnesis disclosed that the patient took hypericin because of depressive mood. We recommended to discontinue hypericin and the symptoms disappeared afterward. Several drugs are able to enhance skin toxicity of RT. Furthermore, the effect of RRD is well known especially for chemotherapy agents such as taxans. However, the underlying mechanisms are not known in detail so far. Moreover, it is unknown whether photosensitising drugs can also be considered to increase radiation sensitivity and whether a recall phenomenon is possible. The first report of a hypericin induced RRD and review of the literature are presented. In clinical practise many interactions between drugs and radiotherapy were not noticed and if registered not published. We recommend to ask especially for complementary or alternative

  19. Modulation of radiation-induced histological and biochemical alterations in mice by Rosemary (Rosemarinus officinalis)

    International Nuclear Information System (INIS)

    Gamma radiation is the most commonly used source of ionizing radiation to treat neoplastic disorders in clinical conditions. Clinical success of radiotherapy depends on its ability to selectively kill tumor cells while sparing the normal surrounding tissues. The response of mammalian cells to ionizing radiation sat the cellular and molecular levels are complex and are an molecular levels is complex and is an irreversible process that is dependent on both the radiation dose and tissue-weighting factor. Recently, increased interest has developed on search for potential drugs of plant origin which can quench the reactive energy of free radicals and eliminate oxygen with minimum side effects. Due to lack of an effective protective agent, newer compounds are currently under investigation as possible adjuvant in the radiation treatment of cancer. This study was undertaken to investigate the radioprotective potential of Rosemarinus officinalis (a medicinal paint) extract (ROE) was studied in mice. For this purpose, Swiss albino mice were exposed to gamma rays (6 Gy) in the absence (control) or presence experimental) of ROE, orally 1000 mg/kg body weight, once daily for 5 consecutive days. A specimen of small intestine was removed from the mice and studied at different autopsy intervals from 12 h to 30 days. In irradiated control animals, crypt cell population, mitotic figures and villus length were markedly reduced on day 1, later these value started to increase progressively but did not attain the normal even till the last autopsy interval. Animals receiving ROE prior to irradiation had a high number of crypt cells, mitotic figures and increase in villus length when compared with non drug treated control at all the autopsy intervals. Irradiation of animals resulted in an elevation of lipid peroxidation and a reduction in glutathione as well as catalase activity in the intestine at 1 hr. post irradiation. In contrast, ROE treatment before irradiation caused a significant

  20. Multidisciplinary approach to assess the sensitivity of dwarf tomato plants to low-LET ionising radiation

    Science.gov (United States)

    De Micco, Veronica; De Pascale, Stefania; Aronne, Giovanna; Paradiso, Roberta; Vitaglione, Paola; Turano, Mimmo; Arena, Carmen

    Ionising radiation, acting alone or in interaction with microgravity and other environmental constraints, may affect plant at molecular, morpho-structural and physiological level. The intensity of the plant’s response depends on the properties of radiation and on the features of the plant itself. Indeed, different species are characterised by different susceptibility to radiation which may change during the life course. The aim of this research was to study the radiosensitivity to low-LET ionising radiation of plants of dwarf tomato (Solanum lycopersicum L. ‘Microtom’) at two phenological phases (vegetative and reproductive), within the purpose of analysing plants for consideration as candidates for Bioregenerative Life Support Systems (BLSS) in Space. To pursue this objective, plants of the cultivar Microtom were irradiated with different doses of X-rays either at the stage of the second true leaf (VP - vegetative phase) or when at least one flower was blossomed (RP - reproductive phase). Plant’s response to ionising radiation was assessed through a multidisciplinary approach combining genetic analyses, ecophysiological measurements, morpho-anatomical characterisation of leaves and fruits, nutritional analyses of fruits. Growth, molecular and morpho-functional traits were measured during plant development up to fruiting in both VP and RP plant groups, and compared with non-irradiated control plants. Plant growth was monitored weekly recording parameters such as plant height, number of leaves, leaf area, flowering and fruiting rate. Potential DNA alterations were explored through Random Amplified Polymorphic DNA (RAPD) technique. The efficiency of the photosynthetic apparatus was evaluated by determining photosynthetic pigment composition, photochemistry and leaf gas exchanges. Leaf and fruit structure were analysed through light and epi-fluorescence microscopy. Leaf anatomical traits related to photosynthetic efficiency, and to structural radioprotection

  1. Exquisite sensitivity of dendritic cells to ultraviolet radiation and temperature changes

    International Nuclear Information System (INIS)

    Recent data suggest that dendritic cells (DC) are the critical passenger leukocytes in allograft rejection. Moreover, previous studies suggest that ultraviolet radiation (UVR) abrogates many in vivo and in vitro immune responses in which DC function as potent accessory cells (AC); however, the mechanism(s) underlying the suppressive effect of UVR on these responses is unclear. To address this mechanism, the hypothesis was tested that loss of DC viability (hence function) accounts for the suppressive effect of UVR on these responses. To this end, in vitro effects of UVR on murine splenic DC viability were addressed using two types of UVR (ultraviolet B [UVB] and ultraviolet C [UVC]) over a UVR dose range of 0-864 J/m2. DC viability was exquisitely sensitive to UVR when compared with other AC populations and UVC was 4-fold more effective in decreasing DC viability than UVB when doses of equal energy were compared. It was found that both UVR types induced marked decreases in DC viability beginning 4-6 hr post-UVR-treatment, that UVR- and non-UVR-induced death were temperature-dependent, and that decreases in DC viability induced by UVR were compatible with interphase death. Our findings indicate that DC are sensitive to temperature changes and exquisitely sensitive to UVR, and suggest that UVR-induced abrogation of murine immune responses is likely attributable to UVR-induced DC death

  2. Sensitivity of planktonic and biofilm-associated Aeromonas spp. to ionizing radiation

    International Nuclear Information System (INIS)

    Aeromonas cells, on radiation sensitivity is isolate specific. (author)

  3. Overfeeding reduces insulin sensitivity and increases oxidative stress, without altering markers of mitochondrial content and function in humans.

    Directory of Open Access Journals (Sweden)

    Dorit Samocha-Bonet

    Full Text Available BACKGROUND: Mitochondrial dysfunction and increased oxidative stress are associated with obesity and type 2 diabetes. High fat feeding induces insulin resistance and increases skeletal muscle oxidative stress in rodents, but there is controversy as to whether skeletal muscle mitochondrial biogenesis and function is altered. METHODOLOGY AND PRINCIPAL FINDINGS: Forty (37 ± 2 y non-obese (25.6 ± 0.6 kg/m(2 sedentary men (n = 20 and women (n = 20 were overfed (+1040 ± 100 kcal/day, 46 ± 1% of energy from fat for 28 days. Hyperinsulinemic-euglycemic clamps were performed at baseline and day 28 of overfeeding and skeletal muscle biopsies taken at baseline, day 3 and day 28 of overfeeding in a sub cohort of 26 individuals (13 men and 13 women that consented to having all 3 biopsies performed. Weight increased on average in the whole cohort by 0.6 ± 0.1 and 2.7 ± 0.3 kg at days 3 and 28, respectively (P<0.0001, without a significant difference in the response between men and women (P = 0.4. Glucose infusion rate during the hyperinsulinemic-euglycemic clamp decreased from 54.8 ± 2.8 at baseline to 50.3 ± 2.5 µmol/min/kg FFM at day 28 of overfeeding (P = 0.03 without a significant difference between men and women (P = 0.4. Skeletal muscle protein carbonyls and urinary F2-isoprostanes increased with overfeeding (P<0.05. Protein levels of muscle peroxisome proliferator-activated receptor gamma coactivator-1α (PGC1α and subunits from complex I, II and V of the electron transport chain were increased at day 3 (all P<0.05 and returned to basal levels at day 28. No changes were detected in muscle citrate synthase activity or ex vivo CO(2 production at either time point. CONCLUSIONS: Peripheral insulin resistance was induced by overfeeding, without reducing any of the markers of mitochondrial content that were examined. Oxidative stress was however increased, and may have contributed to the reduction in insulin sensitivity observed.

  4. Medullary Endocannabinoids Contribute to the Differential Resting Baroreflex Sensitivity in Rats with Altered Brain Renin-Angiotensin System Expression

    Science.gov (United States)

    Schaich, Chris L.; Grabenauer, Megan; Thomas, Brian F.; Shaltout, Hossam A.; Gallagher, Patricia E.; Howlett, Allyn C.; Diz, Debra I.

    2016-01-01

    CB1 cannabinoid receptors are expressed on vagal afferent fibers and neurons within the solitary tract nucleus (NTS), providing anatomical evidence for their role in arterial baroreflex modulation. To better understand the relationship between the brain renin-angiotensin system (RAS) and endocannabinoid expression within the NTS, we measured dorsal medullary endocannabinoid tissue content and the effects of CB1 receptor blockade at this brain site on cardiac baroreflex sensitivity (BRS) in ASrAOGEN rats with low glial angiotensinogen, normal Sprague-Dawley rats and (mRen2)27 rats with upregulated brain RAS expression. Mass spectrometry revealed higher levels of the endocannabinoid 2-arachidonoylglycerol in (mRen2)27 compared to ASrAOGEN rats (2.70 ± 0.28 vs. 1.17 ± 0.09 ng/mg tissue; P NTS did not change cardiac BRS in anesthetized Sprague-Dawley rats (1.04 ± 0.05 ms/mmHg baseline vs. 1.17 ± 0.11 ms/mmHg after 10 min). However, SR141716A in (mRen2)27 rats dose-dependently improved BRS in this strain: 0.36 pmol of SR141716A increased BRS from 0.43 ± 0.03 to 0.71 ± 0.04 ms/mmHg (P < 0.001), and 36 pmol of SR141716A increased BRS from 0.47 ± 0.02 to 0.94 ± 0.10 ms/mmHg (P < 0.01). In contrast, 0.36 pmol (1.50 ± 0.12 vs. 0.86 ± 0.08 ms/mmHg; P < 0.05) and 36 pmol (1.38 ± 0.16 vs. 0.46 ± 0.003 ms/mmHg; P < 0.01) of SR141716A significantly reduced BRS in ASrAOGEN rats. These observations reveal differential dose-related effects of the brain endocannabinoid system that influence cardiovagal BRS in animals with genetic alterations in the brain RAS. PMID:27375489

  5. Medullary Endocannabinoids Contribute to the Differential Resting Baroreflex Sensitivity in Rats with Altered Brain Renin-Angiotensin System Expression.

    Science.gov (United States)

    Schaich, Chris L; Grabenauer, Megan; Thomas, Brian F; Shaltout, Hossam A; Gallagher, Patricia E; Howlett, Allyn C; Diz, Debra I

    2016-01-01

    CB1 cannabinoid receptors are expressed on vagal afferent fibers and neurons within the solitary tract nucleus (NTS), providing anatomical evidence for their role in arterial baroreflex modulation. To better understand the relationship between the brain renin-angiotensin system (RAS) and endocannabinoid expression within the NTS, we measured dorsal medullary endocannabinoid tissue content and the effects of CB1 receptor blockade at this brain site on cardiac baroreflex sensitivity (BRS) in ASrAOGEN rats with low glial angiotensinogen, normal Sprague-Dawley rats and (mRen2)27 rats with upregulated brain RAS expression. Mass spectrometry revealed higher levels of the endocannabinoid 2-arachidonoylglycerol in (mRen2)27 compared to ASrAOGEN rats (2.70 ± 0.28 vs. 1.17 ± 0.09 ng/mg tissue; P NTS did not change cardiac BRS in anesthetized Sprague-Dawley rats (1.04 ± 0.05 ms/mmHg baseline vs. 1.17 ± 0.11 ms/mmHg after 10 min). However, SR141716A in (mRen2)27 rats dose-dependently improved BRS in this strain: 0.36 pmol of SR141716A increased BRS from 0.43 ± 0.03 to 0.71 ± 0.04 ms/mmHg (P < 0.001), and 36 pmol of SR141716A increased BRS from 0.47 ± 0.02 to 0.94 ± 0.10 ms/mmHg (P < 0.01). In contrast, 0.36 pmol (1.50 ± 0.12 vs. 0.86 ± 0.08 ms/mmHg; P < 0.05) and 36 pmol (1.38 ± 0.16 vs. 0.46 ± 0.003 ms/mmHg; P < 0.01) of SR141716A significantly reduced BRS in ASrAOGEN rats. These observations reveal differential dose-related effects of the brain endocannabinoid system that influence cardiovagal BRS in animals with genetic alterations in the brain RAS. PMID:27375489

  6. Radiation Sensitivity in a Preclinical Mouse Model of Medulloblastoma Relies on the Function of the Intrinsic Apoptotic Pathway.

    Science.gov (United States)

    Crowther, Andrew J; Ocasio, Jennifer K; Fang, Fang; Meidinger, Jessica; Wu, Jaclyn; Deal, Allison M; Chang, Sha X; Yuan, Hong; Schmid, Ralf; Davis, Ian; Gershon, Timothy R

    2016-06-01

    While treatments that induce DNA damage are commonly used as anticancer therapies, the mechanisms through which DNA damage produces a therapeutic response are incompletely understood. Here we have tested whether medulloblastomas must be competent for apoptosis to be sensitive to radiotherapy. Whether apoptosis is required for radiation sensitivity has been controversial. Medulloblastoma, the most common malignant brain tumor in children, is a biologically heterogeneous set of tumors typically sensitive to radiation and chemotherapy; 80% of medulloblastoma patients survive long-term after treatment. We used functional genetic studies to determine whether the intrinsic apoptotic pathway is required for radiation to produce a therapeutic response in mice with primary, Shh-driven medulloblastoma. We found that cranial radiation extended the survival of medulloblastoma-bearing mice and induced widespread apoptosis. Expression analysis and conditional deletion studies showed that Trp53 (p53) was the predominant transcriptional regulator activated by radiation and was strictly required for treatment response. Deletion of Bax, which blocked apoptosis downstream of p53, was sufficient to render tumors radiation resistant. In apoptosis-incompetent, Bax-deleted tumors, radiation activated p53-dependent transcription without provoking cell death and caused two discrete populations to emerge. Most radiated tumor cells underwent terminal differentiation. Perivascular cells, however, quickly resumed proliferation despite p53 activation, behaved as stem cells, and rapidly drove recurrence. These data show that radiation must induce apoptosis in tumor stem cells to be effective. Mutations that disable the intrinsic apoptotic pathways are sufficient to impart radiation resistance. We suggest that medulloblastomas are typically sensitive to DNA-damaging therapies, because they retain apoptosis competence. Cancer Res; 76(11); 3211-23. ©2016 AACR. PMID:27197166

  7. Prevention of Radiation Induced Hematological Alterations by Medicinal Plant Rosmarinus Officinalis, in Mice

    OpenAIRE

    Sancheti, Garima; P.K. Goyal

    2006-01-01

    The modulatory influence of Rosmarinus officinalis (rosemary) leaves extract was investigated in Swiss albino mice at a dose of 3 Gy gamma radiation. For this purpose, adult Swiss albino mice were irradiated with 3 Gy gamma rays in the presence (experimental) or absence (control) of rosemary (1000 mg/kg body wt.). These animals were necropsied and their blood was collected at days 1, 3, 5, 10, 20 and 30 post-irradiation. A decrease in the number of erythrocyte and leucocyte counts, hemoglobin...

  8. Characterization of dose-dependent Young's modulus for a radiation-sensitive polymer gel

    International Nuclear Information System (INIS)

    Radiation-sensitive polymer gels for clinical dosimetry have been intensively investigated with magnetic resonance imaging (MRI) because the transversal magnetic relaxation time is dependent on irradiation dose. MRI is expensive and not easily available in most clinics. For this reason, low-cost, quick and easy-to-use potential alternatives such as optical computed tomography (CT), x-ray CT or ultrasound attenuation CT have also been studied by others. Here, we instead evaluate the dose dependence of the elastic material property, Young's modulus and the dose response of the viscous relaxation of radiation-sensitive gels to discuss their potential for dose imaging. Three batches of a radiation-sensitive polymer gel (MAGIC gel) samples were homogeneously irradiated to doses from 0 Gy to 45.5 Gy. Young's modulus was computed from the measured stress on the sample surface and the strain applied to the sample when compressing it axially, and the viscous relaxation was determined from the stress decay under sustained compression. The viscous relaxation was found not to change significantly with dose. However, Young's modulus was dose dependent; it approximately doubled in the gels between 0 Gy and 20 Gy. By fitting a second-order polynomial to the Young's modulus-versus-dose data, 99.4% of the variance in Young's modulus was shown to be associated with the change in dose. The precision of the gel production, irradiation and Young's modulus measurement combined was found to be 4% at 2 Gy and 3% at 20 Gy. Potential sources of measurement error, such as those associated with the boundary conditions in the compression measurement, inhomogeneous polymerization, temperature (up to 1% error) and the evaporation of water from the sample (up to 1% error), were estimated and discussed. It was concluded that Young's modulus could be used for dose determination. Imaging techniques such as elastography may help to achieve this if they can provide a local measurement of Young

  9. The effect of free radical inhibitor on the sensitized radiation crosslinking and thermal processing stabilization of polyurethane shape memory polymers

    International Nuclear Information System (INIS)

    The effects of free radical inhibitor on the electron beam crosslinking and thermal processing stabilization of novel radiation crosslinkable polyurethane shape memory polymers (SMPs) blended with acrylic radiation sensitizers have been determined. The SMPs in this study possess novel processing capabilities—that is, the ability to be melt processed into complex geometries as thermoplastics and crosslinked in a secondary step using electron beam irradiation. To increase susceptibility to radiation crosslinking, the radiation sensitizer pentaerythritol triacrylate (PETA) was solution blended with thermoplastic polyurethane SMPs made from 2-butene-1,4-diol and trimethylhexamethylene diisocyanate (TMHDI). Because the thermoplastic melt processing methods such as injection molding are often carried out at elevated temperatures, sensitizer thermal instability is a major processing concern. Free radical inhibitor can be added to provide thermal stabilization; however, inhibitor can also undesirably inhibit radiation crosslinking. In this study, we quantified both the thermal stabilization and radiation crosslinking inhibition effects of the inhibitor 1,4-benzoquinone (BQ) on polyurethane SMPs blended with PETA. Sol/gel analysis of irradiated samples showed that the inhibitor had little to no inverse effects on gel fraction at concentrations of 0–10,000 ppm, and dynamic mechanical analysis showed only a slight negative correlation between BQ composition and rubbery modulus. The 1,4-benzoquinone was also highly effective in thermally stabilizing the acrylic sensitizers. The polymer blends could be heated to 150 °C for up to 5 h or to 125 °C for up to 24 h if stabilized with 10,000 ppm BQ and could also be heated to 125 °C for up to 5 h if stabilized with 1000 ppm BQ without sensitizer reaction occurring. We believe this study provides significant insight into methods for manipulation of the competing mechanisms of radiation crosslinking and thermal stabilization of

  10. Long-term daily vibration exposure alters current perception threshold (CPT) sensitivity and myelinated axons in a rat-tail model of vibration-induced injury.

    Science.gov (United States)

    Krajnak, Kristine; Raju, Sandya G; Miller, G Roger; Johnson, Claud; Waugh, Stacey; Kashon, Michael L; Riley, Danny A

    2016-01-01

    Repeated exposure to hand-transmitted vibration through the use of powered hand tools may result in pain and progressive reductions in tactile sensitivity. The goal of the present study was to use an established animal model of vibration-induced injury to characterize changes in sensory nerve function and cellular mechanisms associated with these alterations. Sensory nerve function was assessed weekly using the current perception threshold test and tail-flick analgesia test in male Sprague-Dawley rats exposed to 28 d of tail vibration. After 28 d of exposure, Aβ fiber sensitivity was reduced. This reduction in sensitivity was partly attributed to structural disruption of myelin. In addition, the decrease in sensitivity was also associated with a reduction in myelin basic protein and 2',3'- cyclic nucleotide phosphodiasterase (CNPase) staining in tail nerves, and an increase in circulating calcitonin gene-related peptide (CGRP) concentrations. Changes in Aβ fiber sensitivity and CGRP concentrations may serve as early markers of vibration-induced injury in peripheral nerves. It is conceivable that these markers may be utilized to monitor sensorineural alterations in workers exposed to vibration to potentially prevent additional injury. PMID:26852665

  11. Gene expression profiling of human dermal fibroblasts exposed to bleomycin sulphate does not differentiate between radiation sensitive and control patients

    International Nuclear Information System (INIS)

    Gene expression profiling of the transcriptional response of human dermal fibroblasts to in vitro radiation has shown promise as a predictive test of radiosensitivity. This study tested if treatment with the radiomimetic drug bleomycin sulphate could be used to differentiate radiation sensitive patients and controls in patients who had previously received radiotherapy for early breast cancer. Eight patients who developed marked late radiation change assessed by photographic breast appearance and 8 matched patients without any change were selected from women entered in a prospective randomised trial of breast radiotherapy fractionation. Gene expression profiling of primary skin fibroblasts exposed in vitro to bleomycin sulphate and mock treated fibroblast controls was performed. 973 genes were up-regulated and 923 down-reguated in bleomycin sulphate treated compared to mock treated control fibroblasts. Gene ontology analysis revealed enriched groups were cellular localisation, apoptosis, cell cycle and DNA damage response for the deregulated genes. No transcriptional differences were identified between fibroblasts from radiation sensitive cases and control patients; subgroup analysis using cases exhibiting severe radiation sensitivity or with high risk alleles present in TGF β1 also showed no difference. The transcriptional response of human dermal fibroblasts to bleomycin sulphate has been characterised. No differences between clinically radiation sensitive and control patients were detected using this approach

  12. Prenatal Stress Alters Progestogens to Mediate Susceptibility to Sex-Typical, Stress-Sensitive Disorders, such as Drug Abuse: A Review

    OpenAIRE

    Frye, Cheryl A.; Paris, Jason J.; Osborne, Danielle M.; Campbell, Joannalee C.; Kippin, Tod E.

    2011-01-01

    Maternal–offspring interactions begin prior to birth. Experiences of the mother during gestation play a powerful role in determining the developmental programming of the central nervous system. In particular, stress during gestation alters developmental programming of the offspring resulting in susceptibility to sex-typical and stress-sensitive neurodevelopmental, neuropsychiatric, and neurodegenerative disorders. However, neither these effects, nor the underlying mechanisms, are well underst...

  13. Prenatal stress alters progestogens to mediate susceptibility to sex-typical, stress-sensitive disorders, such as drug abuse: a review

    OpenAIRE

    Frye, Cheryl A.; Paris, Jason J.; Danielle eOsborne; Joanna eCampbell; Tod eKippin

    2011-01-01

    Maternal-offspring interactions begin prior to birth. Experiences of the mother during gestation play a powerful role in determining the developmental programming of the central nervous system. In particular, stress during gestation alters developmental programming of the offspring resulting in susceptibility to sex-typical and stress-sensitive neurodevelopmental, neuropsychiatric and neurodegenerative disorders. However, neither these effects, nor the underlying mechanisms, are well unders...

  14. Radiation sensitivity of foodborne pathogens in meat byproducts with different packaging

    Science.gov (United States)

    Yong, Hae In; Kim, Hyun-Joo; Nam, Ki Chang; Kwon, Joong Ho; Jo, Cheorun

    2015-10-01

    The aim of this study was to determine radiation sensitivity of Escherichia coli O157:H7 and Listeria monocytogenes in edible meat byproducts. Seven beef byproducts (heart, liver, lung, lumen, omasum, large intestine, and small intestine) and four pork byproducts (heart, large intestine, liver, and small intestine) were used. Electron beam irradiation significantly reduced the numbers of pathogenic microorganisms in meat byproducts and no viable cells were detected in both aerobically- and vacuum-packaged samples irradiated at 4 kGy. Meat byproducts packed under vacuum had higher D10 value than the ones packed aerobically. No significant difference was observed between the D10 values of E. coli O157:H7 and L. monocytogenes inoculated in either aerobically or vacuum packaged samples. These results suggest that low-dose electron beam irradiation can significantly decrease microbial numbers and reduce the risk of meat byproduct contamination by the foodborne pathogens.

  15. Radiation synthesis and characterization of stimuli-sensitive chitosan-polyvinyl pyrrolidone hydrogels

    International Nuclear Information System (INIS)

    Novel cationic hydrogels were synthesized by γ-irradiation copolymerization of chitosan and polyvinyl pyrrolidone (PVP). The synthesis regularities and the swelling behaviour of hydrogels have been studied. It was shown that increasing of PVP concentration in feed composition also as radiation dose accompanied of increase of yield of gel fraction and decrease of swelling degree. At dose more than 3.5 kGy increasing of swelling degree and decreasing of gel fraction yield have been observed. It was shown that the hydrogels exhibit pH-sensitive behaviour in aqueous solution. In solutions of sodium dodecyl sulfate (SDS) the hydrogels are collapsed due to complexation, however, at concentration of SDS solution equal to critical micelle concentration the gels contracted and then swollen again

  16. The radiation sensitivity of the haemopoietic microenvironment - effect of dose rate on ectopic ossicle formation

    International Nuclear Information System (INIS)

    The haemopoietic microenvironment (HM) consists of a complex mixture of cellular types and extra-cellular matrix. It is essential for prolonged haemopoiesis in both the normal situation and after bone marrow transplantation. The competence of the HM can be assessed by ectopic grafting of femoral marrow. A complete haemopoietic organ develops at the site of implantation. Stem cells (CFU-S) which inhabit the ossicle formed after ectopic implantation can be measured, to assess the function of the engrafted HM to support haemopoiesis. Using this functional endpoint the radiation sensitivity of the HM has been examined at both high and low dose rates, and it is concluded that high doses of γ-irradiation delivered at 4 Gy/min or 0.016 Gy/min have widely different effects on the HM, the former proving much more damaging than the latter. 16 refs.; 2 figs

  17. Radiation-sensitive mutant of hypertoxinogenic strain 569B of Vibro cholerae

    International Nuclear Information System (INIS)

    A radiation-sensitive mutant of the hypertoxinogenic strain 569B of Vibrio cholerae was isolated and characterized. The mutant, designated V. cholerae 569Bsub(s), lacks both excision- and medium-dependent dark-repair mechanisms of UV-induced DNA damage while retaining the wild-type photoreactivating capability. Analysis of the UV-irradiated cell DNA by velocity sedimentation in alkaline sucrose gradient suggests that UV-induced pyrimidine dimers may not be incised in these cells. In contrast to the wild-type cells, the mutant cell DNA was degraded after treatment with nalidixic acid. The mutant cells failed to produce any detectable amount of cholera toxin as measured by ileal-loop assay. (orig.)

  18. Application of generalized estimating equations to a study in vitro of radiation sensitivity

    International Nuclear Information System (INIS)

    We describes an application of the generalized estimating equation (GEE) method (Liang K-Y, Zeger SL: Longitudinal data analysis using generalized linear models. Biometrika 73:13-22, 1986) for regression analyses of correlated Poisson data. As an alternative to the use of an arbitrarily chosen working correlation matrix, we demonstrate the use of GEE with a reasonable model for the true covariance structure among repeated observations within individuals. We show that, under such a split-plot design with large clusters, the asymptotic relative efficiency of GEE with simple (independence or exchangeable) working correlation matrices is rather low. We also illustrate the use of GEE with an empirically estimated model for overdispersion in a large study of radiation sensitivity where cluster size is small and a simple working correlation structure is sufficient. We conclude by summarizing issues and needs for further work concerning efficiency of the GEE parameter estimates in practice. (author)

  19. Study of the sensitivity of the radiation transport problem in a scattering medium

    International Nuclear Information System (INIS)

    In this work, the system of differential equations obtained by the angular approach of the two-dimensional transport equation by the discrete ordinates method is solved through the formulation of finite elements with the objective of investigating the sensitivity of the outgoing flux of radiation with the incoming flux and the properties of absorption and scattering of the medium. The variational formulation for the system of differential equations of second order with the generalized boundary conditions of Neumann (third type) allows an easy implementation of the method of the finite elements with triangular mesh and approximation space of first order. The geometry chosen for the simulations is a circle with a non homogeneous circular form in its interior. The mapping of Dirichlet-Neumann is studied through various simulations involving the incoming flux, the outgoing flux and the properties of the medium. (author)

  20. Can climate sensitivity be estimated from short-term relationships of top-of-atmosphere net radiation and surface temperature?

    International Nuclear Information System (INIS)

    Increasing the knowledge in climate radiative feedbacks is critical for current climate studies. This work focuses on short-term relationships between global mean surface temperature and top-of-atmosphere (TOA) net radiation. The relationships may be used to characterize the climate feedback as suggested by some recent studies. As those recent studies, an energy balance model with ocean mixed layer and both radiative and non-radiative heat sources is used here. The significant improvement of current model is that climate system memories are considered. Based on model simulations, short-term relationship between global mean surface temperature and TOA net radiation (or the linear striation feature as suggested by previous studies) might represent climate feedbacks when the system had no memories. However, climate systems with the same short-term feedbacks but different memories would have a similar linear striation feature. This linear striation feature reflects only fast components of climate feedbacks and may not represent the total climate feedback even when the memory length of climate systems is minimal. The potential errors in the use of short-term relationships in estimations of climate sensitivity could be big. In short time scales, fast climate processes may overwhelm long-term climate feedbacks. Thus, the climate radiative feedback parameter obtained from short-term data may not provide a reliable estimate of climate sensitivity. This result also suggests that long-term observations of global surface temperature and TOA radiation are critical in the understanding of climate feedbacks and sensitivities.

  1. Evaluation of the radiation-sensitizer/protector and/or antioxidant efficiencies using Fricke and PAG dosimeters

    Science.gov (United States)

    Meesat, Ridthee; Jay-Gerin, Jean-Paul; Khalil, Abdelouahed; Lepage, Martin

    2009-05-01

    In this study, our aim is to assess the potential of Fricke and polyacrylamide gel (PAG) dosimeters to quantitatively evaluate the efficiency of potential radiation sensitizers/protectors and antioxidants. These compounds are of importance in radiotherapy as well as in disease prevention and promotion of health. The basic principle of the Fricke dosimeter is the radiation-induced oxidation of Fe2+ to Fe3+ in an aerated aqueous 0.4 M H2SO4. The production of ferric ions is most sensitive to the radical species produced in the radiolysis of water. Using this method, we observed that cystamine (one of the best of the known radioprotectors) can prevent oxydation of Fe2+ from reactive radiolysis species. However, one obvious disadvantage of the Fricke dosimeter is that it operates under highly acidic conditions (pH 0.46), which may degrade biological compounds. In contrast, the pH of the polyacrylamide gel (PAG) dosimeter is almost neutral, such that degradation of compounds is less probable. A change in R2-dose sensitivity was observed in the presence of radiosensitizers/radioprotectors and antioxidants. The protective effect of Trolox (a well-known antioxidant) and thiourea (a radioprotector) was readily observed using the PAG dosimeter. Incorporation of iodinated radiation sensitizers such as NaI and an iodine contrast agent led to a quantifiable sensitizer enhancement ratio. These studies suggest that the Fricke and the PAG dosimeters have the potential to evaluate the efficiency of radiation sensitizers/protectors and antioxidants.

  2. Evidence that Characean membrane transport is not significantly altered by incident electromagnetic radiation

    Energy Technology Data Exchange (ETDEWEB)

    Gokhale, A.V.; Pickard, W.F.

    1985-06-01

    Giant cells of the algae Chara braunii and Nitella flexilis were exposed to VHF, UHF, and X-Band electromagnetic radiation. Their responses were measured by examining their vacuolar potential for dc offsets with various rise times, very small ac offsets phase-locked to a pulse modulation frequency, and slow drifts in the RMS level of membrane noise over the band 0.2-2.0 Hz. Both continuous-wave (CW) and pulsed irradiation protocols were employed, and the cw was used in both discrete frequency and swept-frequency modes. The average power levels ranged from 0.1 to 5000 W/m/sup 2/. In no case was a bioeffect detected.

  3. Radiation sensitivity of natural organic matter: Clay mineral association effects in the Callovo-Oxfordian argillite

    International Nuclear Information System (INIS)

    Clay-rich low-organic carbon formations (e.g., Callovo-Oxfordian argillite in France and Opalinus Clay in Switzerland) are considered as host rocks for radioactive waste disposal. The clay-organic carbon has a strong impact on the chemical stability of the clays. For this reason, the nature of the clay-organic carbon, the release of hydrophilic organic compounds, namely, humic (HA) and fulvic acids (FA) and the radiation sensitivity of the undisturbed host rock organics was investigated. The clay sample originates from Oxfordian argillite (447 m depth, borehole EST 104). HA and FA were extracted following the standard International Humic Substance Society (IHSS) isolation procedure. Synchrotron based (C-, K-, Ca-, O- and Fe-edge XANES) scanning transmission X-ray microscopy (STXM) and FT-IR microspectroscopy was used to identify under high spatial resolution the distribution of clay-organic matter with different functionality using principal component and cluster analysis. The results show that in this old (Jurassic) geological formation, small parts of the organic inventory (1-5%) keeps the structure/functionality and can be mobilized as hydrophilic humic substance type material (HA and FA). Target spectra analysis shows best correlation for isolated humic acids with organics found in smectite-rich regions, whereas the extractable FA has better spectral similarities with the illite mixed layer minerals (MLM) regions. After radiation of 1.7 GGy under helium atmosphere the same rock sample area was investigated for radiation damage. Radiation damage in the smectite and illite-MLM associated organic matter is comparably low with 20-30% total oxygen mass loss and 13-18% total carbon mass loss. A critical dose dc of 2.5 GGy and a optical density after infinite radiation (OD∝) of 54% was calculated under room temperature conditions. C(1s) XANES show a clear increase in C=C bonds especially in the illite-MLM associated organics. This results suggests a combination of

  4. Radiation sensitive indicator based on tetrabromophenol blue dyed poly(vinyl alcohol)

    International Nuclear Information System (INIS)

    Radiation sensitive indicators based on dyed polyvinyl alcohol (PVA) containing acid- sensitive dye (tetrabromophenol blue, TBPB) and chloral hydrate (CCl3·CH·(OH)2, 2,2,2-trichloroethane-1,1-diol) have been developed. These plastic film dosimeters undergo color change from blue (the alkaline form of TBPB) to yellow (the acidic form of TBPB), indicating acid formation. The concentration of radiation formed acids in the films containing different concentrations of chloral hydrate was calculated at different doses. These films can be used as dosimeters for food irradiation applications where the maximum of the useful dose ranges are between 1 and 8 kGy depending on chloral hydrate concentration in the film. The films have the advantage of negligible humidity effects on response in the intermediate range of relative humidity from 0 to 70% as good post irradiation stability when stored in the dark at room temperature. The overall combined uncertainty (at 2σ) associated with measurement of response (ΔA mm−1) at 623 nm for dose range 1–8 kGy is 4.53%. - Highlights: ► On irradiating TBPB/PVA films the color change from blue to green and yellow. ► The amount of acid formed depends on dose and concentration of chloral hydrate. ► The dose range 1–8 kGy the film can be used for food irradiation applications. ► The response of these films has negligible humidity effects from 0 to 70%. ► The combined uncertainty at 2σ using TBPB/PVA films was found to be 4.53%

  5. Oxygen at 2 atmospheres absolute pressure does not increase the radiation sensitivity of normal brain in rats

    International Nuclear Information System (INIS)

    Cranial radiation was administered to CD Fisher rats at 1.0, 1.5 and 2.0 atmospheres oxygen pressure. Life span following radiation was recorded. Surviving animals were killed at 28 weeks and the brains were examined independently by two neuropathologists. Survival time was significantly less in animals receiving higher doses of radiation but showed no relationship to the oxygen pressure in the environment of the animal at the time radiation was administered. Microscopic examination of the brain did not reveal any differences in animals radiated in a normobaric or hyperbaric oxygen environment. It is concluded that hyperbaric oxygen does not sensitize the normal brain to the effects of ionizing radiation

  6. Higher sensitivity of LEC strain rat in radiation-induced acute intestinal death

    International Nuclear Information System (INIS)

    LEC strain rats (LEC rats), which have been known to develop hereditarily spontaneous fulminant hepatitis 4-5 months after birth, were highly sensitive to whole-body X-irradiation as compared to WKAH strain rats (WKAH rats). Radiation-induced acute intestinal death occurred at doses higher than 6.5 Gy in LEC rats, and at doses higher than 12.8 Gy in WKAH rats, respectively. By the probit analysis of survival data, it was shown that the LD50/7 value of LEC rats was estimated to be 7.03 Gy which was significantly lower than that (12.99 Gy) of WKAH rats. Histopathological examinations of small intestines from LEC rats 2 days after irradiation at the dose of 8.5 Gy showed severe epithelial death together with edema, whereas little or no significant changes were noted in intestinal epithelium of 8.5 Gy-irradiated WKAH rats. These results suggest that the radiosensitivity of LEC rats to ionizing radiation appears to be higher than that of other strains of rats

  7. A system for determining the pharmacology of indirect radiation sensitizer drugs on multicellular spheroids

    International Nuclear Information System (INIS)

    We have characterized some of the physiology of multicellular spheroids of different sizes grown from Chinese hamster lung fibroblast (V79) cells. Among the parameters studied were oxygen tension distributions within the spheroid. This was achieved using ultramicroelectrodes with tip diameters of 1-5 mu and a perfusion system whereby environmental conditions such as flow, temperature, and chemical makeup of the milieu could be measured and controlled. Plateau pO/sup 2/ values of less than 10 mm Hg were consistently obtained from spheroids under various conditions. We were able to modify these distributions by use of indirect radiation sensitizer drugs such as mechlorethamine HCl (mustargen) at nontoxic doses. We have also made determinations of the inhibitory capacities of several other drugs on the respiration rate of constituent cells of multicellular spheroids in single-cell suspensions. We have concluded that there are indeed hypoxic cells in spheroids whose radioresistance may be modified by essentially nontoxic levels of indirect radiosensitizer drugs and that the system described shows great promise for screening agents which may modify radiation response

  8. Global Gene Expression Alterations as a Crucial Constituent of Human Cell Response to Low Doses of Ionizing Radiation Exposure

    Directory of Open Access Journals (Sweden)

    Mykyta Sokolov

    2015-12-01

    Full Text Available Exposure to ionizing radiation (IR is inevitable to humans in real-life scenarios; the hazards of IR primarily stem from its mutagenic, carcinogenic, and cell killing ability. For many decades, extensive research has been conducted on the human cell responses to IR delivered at a low dose/low dose (LD rate. These studies have shown that the molecular-, cellular-, and tissue-level responses are different after low doses of IR (LDIR compared to those observed after a short-term high-dose IR exposure (HDIR. With the advent of high-throughput technologies in the late 1990s, such as DNA microarrays, changes in gene expression have also been found to be ubiquitous after LDIR. Very limited subset of genes has been shown to be consistently up-regulated by LDIR, including CDKN1A. Further research on the biological effects and mechanisms induced by IR in human cells demonstrated that the molecular and cellular processes, including transcriptional alterations, activated by LDIR are often related to protective responses and, sometimes, hormesis. Following LDIR, some distinct responses were observed, these included bystander effects, and adaptive responses. Changes in gene expression, not only at the level of mRNA, but also miRNA, have been found to crucially underlie these effects having implications for radiation protection purposes.

  9. A robust hypothesis test for the sensitive detection of constant speed radiation moving sources

    Energy Technology Data Exchange (ETDEWEB)

    Dumazert, Jonathan, E-mail: jonathan.dumazert@cea.fr [CEA, LIST, Laboratoire Capteurs Architectures Electroniques, 91191 Gif-sur-Yvette (France); Coulon, Romain; Kondrasovs, Vladimir; Boudergui, Karim; Moline, Yoann; Sannié, Guillaume; Gameiro, Jordan; Normand, Stéphane [CEA, LIST, Laboratoire Capteurs Architectures Electroniques, 91191 Gif-sur-Yvette (France); Méchin, Laurence [CNRS, UCBN, Groupe de Recherche en Informatique, Image, Automatique et Instrumentation de Caen, 14050 Caen (France)

    2015-09-21

    Radiation Portal Monitors are deployed in linear networks to detect radiological material in motion. As a complement to single and multichannel detection algorithms, inefficient under too low signal-to-noise ratios, temporal correlation algorithms have been introduced. Test hypothesis methods based on empirically estimated mean and variance of the signals delivered by the different channels have shown significant gain in terms of a tradeoff between detection sensitivity and false alarm probability. This paper discloses the concept of a new hypothesis test for temporal correlation detection methods, taking advantage of the Poisson nature of the registered counting signals, and establishes a benchmark between this test and its empirical counterpart. The simulation study validates that in the four relevant configurations of a pedestrian source carrier under respectively high and low count rate radioactive backgrounds, and a vehicle source carrier under the same respectively high and low count rate radioactive backgrounds, the newly introduced hypothesis test ensures a significantly improved compromise between sensitivity and false alarm. It also guarantees that the optimal coverage factor for this compromise remains stable regardless of signal-to-noise ratio variations between 2 and 0.8, therefore allowing the final user to parametrize the test with the sole prior knowledge of background amplitude.

  10. A robust hypothesis test for the sensitive detection of constant speed radiation moving sources

    International Nuclear Information System (INIS)

    Radiation Portal Monitors are deployed in linear networks to detect radiological material in motion. As a complement to single and multichannel detection algorithms, inefficient under too low signal-to-noise ratios, temporal correlation algorithms have been introduced. Test hypothesis methods based on empirically estimated mean and variance of the signals delivered by the different channels have shown significant gain in terms of a tradeoff between detection sensitivity and false alarm probability. This paper discloses the concept of a new hypothesis test for temporal correlation detection methods, taking advantage of the Poisson nature of the registered counting signals, and establishes a benchmark between this test and its empirical counterpart. The simulation study validates that in the four relevant configurations of a pedestrian source carrier under respectively high and low count rate radioactive backgrounds, and a vehicle source carrier under the same respectively high and low count rate radioactive backgrounds, the newly introduced hypothesis test ensures a significantly improved compromise between sensitivity and false alarm. It also guarantees that the optimal coverage factor for this compromise remains stable regardless of signal-to-noise ratio variations between 2 and 0.8, therefore allowing the final user to parametrize the test with the sole prior knowledge of background amplitude

  11. A robust hypothesis test for the sensitive detection of constant speed radiation moving sources

    Science.gov (United States)

    Dumazert, Jonathan; Coulon, Romain; Kondrasovs, Vladimir; Boudergui, Karim; Moline, Yoann; Sannié, Guillaume; Gameiro, Jordan; Normand, Stéphane; Méchin, Laurence

    2015-09-01

    Radiation Portal Monitors are deployed in linear networks to detect radiological material in motion. As a complement to single and multichannel detection algorithms, inefficient under too low signal-to-noise ratios, temporal correlation algorithms have been introduced. Test hypothesis methods based on empirically estimated mean and variance of the signals delivered by the different channels have shown significant gain in terms of a tradeoff between detection sensitivity and false alarm probability. This paper discloses the concept of a new hypothesis test for temporal correlation detection methods, taking advantage of the Poisson nature of the registered counting signals, and establishes a benchmark between this test and its empirical counterpart. The simulation study validates that in the four relevant configurations of a pedestrian source carrier under respectively high and low count rate radioactive backgrounds, and a vehicle source carrier under the same respectively high and low count rate radioactive backgrounds, the newly introduced hypothesis test ensures a significantly improved compromise between sensitivity and false alarm. It also guarantees that the optimal coverage factor for this compromise remains stable regardless of signal-to-noise ratio variations between 2 and 0.8, therefore allowing the final user to parametrize the test with the sole prior knowledge of background amplitude.

  12. Radiation sensitivity of bacteria and virus in porcine xenoskin for dressing agent

    Science.gov (United States)

    Jo, Eu-Ri; Jung, Pil-Mun; Choi, Jong-il; Lee, Ju-Woon

    2012-08-01

    In this study, gamma irradiation sensitivities of bacteria and viruses in porcine skin were evaluated to establish the optimum sterilization condition for the dressing material and a xenoskin graft. Escherichia coli and Bacillus subtilis were used as model pathogens and inoculated at 106-107 log CFU/g. As model viruses, porcine parvovirus (PPV), bovine viral diarrhea virus (BVDV), and poliovirus were used and inoculated at 105-106 TCID50/g into porcine skin. The D10 value of E. coli was found to be 0.25±0.1 kGy. B. subtilis endospores produced under stressful environmental conditions showed lower radiation sensitivity as D10 was 3.88±0.3 kGy in porcine skin. The D10 values of PPV, BVDV, and poliovirus were found to be 1.73±0.2, 3.81±0.2, and 6.88±0.3 kGy, respectively. These results can offer the basic information required for inactivating pathogens by gamma irradiation and achieving dressing material and porcine skin grafts.

  13. Radiation sensitivity of bacteria and virus in porcine xenoskin for dressing agent

    International Nuclear Information System (INIS)

    In this study, gamma irradiation sensitivities of bacteria and viruses in porcine skin were evaluated to establish the optimum sterilization condition for the dressing material and a xenoskin graft. Escherichia coli and Bacillus subtilis were used as model pathogens and inoculated at 106–107 log CFU/g. As model viruses, porcine parvovirus (PPV), bovine viral diarrhea virus (BVDV), and poliovirus were used and inoculated at 105–106 TCID50/g into porcine skin. The D10 value of E. coli was found to be 0.25±0.1 kGy. B. subtilis endospores produced under stressful environmental conditions showed lower radiation sensitivity as D10 was 3.88±0.3 kGy in porcine skin. The D10 values of PPV, BVDV, and poliovirus were found to be 1.73±0.2, 3.81±0.2, and 6.88±0.3 kGy, respectively. These results can offer the basic information required for inactivating pathogens by gamma irradiation and achieving dressing material and porcine skin grafts.

  14. Progressive alterations of central nervous system structure and function are caused by charged particle radiation

    Science.gov (United States)

    Nelson, G. A.; Cns Nscor Team

    A new NASA-sponsored program project (NSCOR) has been organized to conduct the first comprehensive investigation of the response of a mammalian brain structure (mouse hippocampus) to charged-particle radiation. The NSCOR collaboration has three main goals. The first goal is to quantify the time- and dose-dependent changes in cellular composition and architecture. By using stereology on preserved brains, subsets of cells (neurons, glia, endothelia and stem cells) will be quantified out to 2 years after irradiation with accelerated protons and iron ions. To further characterize changes in vasculature architecture a polymer infusion technique will be used to produce a three-dimensional vasculature cast that then will be mapped by x-ray tomography to determine topological changes, and microscopic infarcts associated with amyloid protein deposits. The 2nd goal is to quantify hippocampal function(s). The primary measurement of function will be extracellular electrical recordings from hippocampal ``brain slices'' that reflect underlying functions such as connectivity, action potential generation & conduction, and neurotransmitter formation, secretion, and uptake. Individual nerve membrane properties will be assessed by ``patch clamp'' recordings. Two non-invasive methods will evaluate brain function and the evolution of changes with time. Electroencephalograms will map macroscopic spontaneous electrical activity while two state-of-the-art MRI magnetization sequences will visualize and quantify local oxygen utilization and white matter fiber tracts structural integrity. To quantify the brains' overall performance under stress, animals will receive a systemic shock mediated by the immune system in the form of a reaction to lipopolysaccharide. A second strategy will employ the APP23 transgenic mouse that develops the pathological changes associated with Alzheimer's disease. Measurements of irradiated mice will determine whether radiation exposure affects the latency and

  15. Sensitivity Analysis on Fu-Liou-Gu Radiative Transfer Model for different lidar aerosol and cloud profiles

    Science.gov (United States)

    Lolli, Simone; Madonna, Fabio; Rosoldi, Marco; Pappalardo, Gelsomina; Welton, Ellsworth J.

    2016-04-01

    The aerosol and cloud impact on climate change is evaluated in terms of enhancement or reduction of the radiative energy, or heat, available in the atmosphere and at the Earth's surface, from the surface (SFC) to the Top Of the Atmosphere (TOA) covering a spectral range from the UV (extraterrestrial shortwave solar radiation) to the far-IR (outgoing terrestrial longwave radiation). Systematic Lidar network measurements from permanent observational sites across the globe are available from the beginning of this current millennium. From the retrieved lidar atmospheric extinction profiles, inputted in the Fu-Liou-Gu (FLG) Radiative Transfer code, it is possible to evaluate the net radiative effect and heating rate of the different aerosol species and clouds. Nevertheless, the lidar instruments may use different techniques (elastic lidar, Raman lidar, multi-wavelength lidar, etc) that translate into uncertainty of the lidar extinction retrieval. The goal of this study is to assess, applying a MonteCarlo technique and the FLG Radiative Transfer model, the sensitivity in calculating the net radiative effect and heating rate of aerosols and clouds for the different lidar techniques, using both synthetic and real lidar data. This sensitivity study is the first step to implement an automatic algorithm to retrieve the net radiative forcing effect of aerosols and clouds from the long records of aerosol measurements available in the frame of EARLINET and MPLNET lidar networks.

  16. Suppression of DNA-dependent protein kinase sensitize cells to radiation without affecting DSB repair

    Energy Technology Data Exchange (ETDEWEB)

    Gustafsson, Ann-Sofie, E-mail: ann-sofie.gustafsson@bms.uu.se; Abramenkovs, Andris; Stenerlöw, Bo

    2014-11-15

    Highlights: • We reduced the level of DNA-PKcs with siRNA and examined cells after γ-irradiation. • Low DNA-PKcs levels lead to radiosensitivity but did not affect repair of DSB. • Low DNA-PKcs levels may block progression of mitosis. • DNA-PKcs role in mitotic progression is independent of its role in DSB repair. • We suggest different mechanisms by which loss of DNA-PKcs function sensitize cells. - Abstract: Efficient and correct repair of DNA double-strand break (DSB) is critical for cell survival. Defects in the DNA repair may lead to cell death, genomic instability and development of cancer. The catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) is an essential component of the non-homologous end joining (NHEJ) which is the major DSB repair pathway in mammalian cells. In the present study, by using siRNA against DNA-PKcs in four human cell lines, we examined how low levels of DNA-PKcs affected cellular response to ionizing radiation. Decrease of DNA-PKcs levels by 80–95%, induced by siRNA treatment, lead to extreme radiosensitivity, similar to that seen in cells completely lacking DNA-PKcs and low levels of DNA-PKcs promoted cell accumulation in G2/M phase after irradiation and blocked progression of mitosis. Surprisingly, low levels of DNA-PKcs did not affect the repair capacity and the removal of 53BP1 or γ-H2AX foci and rejoining of DSB appeared normal. This was in strong contrast to cells completely lacking DNA-PKcs and cells treated with the DNA-PKcs inhibitor NU7441, in which DSB repair were severely compromised. This suggests that there are different mechanisms by which loss of DNA-PKcs functions can sensitize cells to ionizing radiation. Further, foci of phosphorylated DNA-PKcs (T2609 and S2056) co-localized with DSB and this was independent of the amount of DNA-PKcs but foci of DNA-PKcs was only seen in siRNA-treated cells. Our study emphasizes on the critical role of DNA-PKcs for maintaining survival after radiation exposure

  17. Protective efficacy of Emblica officinalis Linn. against radiation and cadmium induced biochemical alterations in the brain of Swiss albino mice

    International Nuclear Information System (INIS)

    One of the major problems faced in the modern world today is that of pollution caused due to radioactive material and emission of gamma radiation from various sources either in terms of background radiation sources, accidental leak from nuclear reactors or intentional convert attack by terrorists to achieve the malefic goals. In view of such perceived risks and threats associated with plausible radiological and nuclear incidents. It is pertained to develop potential drugs for the mitigation of deleterious effects of ionizing radiation and heavy metals. In recent years, immense interest has been developed in the field of chemoprotection against radiation and heavy metal induced changes. In light of above the present study was aimed to evaluate the protective efficacy of Emblica officinalis against Radiation and cadmium induced biochemical alteration in the Brain of Swiss Albino mice. The animals were exposed to 3.0 Gy of gamma rays with or without cadmium chloride treatment. The Emblica extract was administered seven days prior to irradiation or cadmium chloride treatment. The animals from all the experimental groups were sacrificed by cervical dislocation at each post-treatment interval of 1, 2, 4, 7, 14 and 28 days. After sacrificing the animals, mid brains (cerebral hemisphere) were taken out and kept at -20 deg C for different biochemical parameters. It was The values of total proteins, cholesterol and DNA decreased up to day-14 in non drug treated groups and day-7 in the Emblica treated groups thereafter it increased on day-28, whereas the value of glycogen, Acid phosphatase activity, Alkaline phosphatase activity and RNA increased up to day-14 in non drug treated groups and day-7 in drug treated groups, thereafter it decreased on day-28 in all the groups. In the combined treatment groups the biochemical changes were more prominent showing synergistic or additive effect. In the Emblica pretreated animals the changes were less severe and an early and fast

  18. A position-sensitive scintillation detector for two-dimensional angular correlation of annihilation radiation using metal-package position-sensitive photomultiplier tubes

    International Nuclear Information System (INIS)

    We have constructed and tested a prototype of a new position sensitive γ-ray detector which consists of an array of 2.6x2.6x18 mm3 BGO scintillator blocks, a light guide, and four metal-package position-sensitive photomultiplier tubes (R5900-00-C8) recently developed by Hamamatsu Photonics Co. Ltd. Scalability of the detector of this type makes it possible to construct a larger detector using many PS-PMTs, which will be useful for the two-dimensional angular correlation of annihilation radiation apparatus

  19. A position-sensitive scintillation detector for two-dimensional angular correlation of annihilation radiation using metal-package position-sensitive photomultiplier tubes

    CERN Document Server

    Inoue, K; Saito, H; Nagashima, Y; Hyodo, T; Muramatsu, S; Nagai, S

    1999-01-01

    We have constructed and tested a prototype of a new position sensitive gamma-ray detector which consists of an array of 2.6x2.6x18 mm sup 3 BGO scintillator blocks, a light guide, and four metal-package position-sensitive photomultiplier tubes (R5900-00-C8) recently developed by Hamamatsu Photonics Co. Ltd. Scalability of the detector of this type makes it possible to construct a larger detector using many PS-PMTs, which will be useful for the two-dimensional angular correlation of annihilation radiation apparatus.

  20. Radiation Induced-Grafting of Sensitive Binary Monomers onto Polypropylene Films by γ-Rays

    International Nuclear Information System (INIS)

    Binary graft copolymerization of pH sensitive acrylic acid (AAc) and thermosensitive N-isopropylacrylamide (NIPAAm) monomers onto polypropylene films (PP), was carried out by two steps method, and their pH and thermal sensitivity were studied. Graft polymerization of AAc onto PP was carried out by a pre-irradiation oxidative method using a 60Co gamma radiation source (Gamma Beam 651 PT, Nordion International Inc.) with activity of 25,000 Curies. The influence of synthesis conditions, such as pre-irradiation dose, reaction time, monomer concentration, and reaction temperature was studied. Grafting of PP films of 1 x 5 cm size was carried out in glass ampoules, pre-irradiated films in air, were placed in ampoules containing monomer (AAc) in water (40/60 % vol.). Argon was purged into the ampoule to remove air trapped inside the reaction mixture and the ampoule was subsequently placed at the constant temperature of 50 degree at different reaction time; then the PP films were extracted with water to remove any homopolymer formed in the reaction. The samples were dried under vacuum and the graft percentage was determined. Grafting of NIPAAm onto PP-g-AAc was carried out with the same procedure. Low Critical Solution Temperature (LCST) of the films was measured by water absorption and water contact angle, and the thermosensitivity of the samples, defined as the ratio of the grafted samples swelling percentage at room temperature and 35 degree, and pH sensitivity defined as the ratio of the grafted samples swelling percentage at pH 2 and 8, were calculated. Binary grafting was confirmed by Infrared (FTIR-ATR)

  1. Positron emission tomography (PET) study of the alterations in brain pharmacokinetics of methamphetamine in methamphetamine sensitized animals

    International Nuclear Information System (INIS)

    I investigated the differences in brain pharmacokinetics of [11C]methamphetamine ([11C]MAP) in normal and MAP sensitized animals using positron emission tomography (PET). [11C]MAP was synthesized by an automated on-line [11C]methylation system. I newly produced MAP sensitized dog and monkey by repeated MAP treatment. The maximal level of accumulation of [11C]MAP in the sensitized dog brain was 1.4 times higher than that in the control. This result suggests the changes in the pharmacokinetic profile of MAP in the brain affect the development or expression of MAP-induced behavioral sensitization. However, the overaccumulation of [11C]MAP in the sensitized monkey brain was not observed due to the influence of anesthesia. (author)

  2. Calibration of non-discriminating scintillating instruments for sensitivities to naturally occuring gamma radiation emitting radionuclides at environmental concentrations

    International Nuclear Information System (INIS)

    A method of calibrating non-discriminating gamma radiation detectors for environmental level measurements is described. It is based on a method used to calibrate field gamma spectrometers, and has several advantages over the more traditional point-source approach. Radiological measurements are taken on pads with known concentrations of potassium, uranium and thorium, and the sensitivities to these naturally occurring terrestrial sources of gamma radiation are determined. Measurements can then be converted into radionuclide concentration or exposure rates. (author)

  3. Investigation of some parameters influencing the sensitivity of human tooth enamel to gamma radiation using electron paramagnetic resonance

    International Nuclear Information System (INIS)

    Electron paramagnetic resonance (EPR) has been successfully used as a physical technique for gamma radiation dose reconstruction using calcified tissues. To minimize potential discrepancies between EPR readings in future studies, the effects of cavity response factor, tooth position and donor gender on the estimated gamma radiation dose were studied. It was found that the EPR response per sample mass used for assessment of doses in teeth outside of the 70-100 mg range should be corrected by a factor which is a function of the sample mass. In the EPR measurements, the difference in sensitivity of different tooth positions to γ-radiation was taken into consideration. It was determined that among all the premolars and molars tooth positions, the relative standard deviation of sensitivity was 6.5%, with the wisdom teeth and the first molars having the highest and lowest sensitivity to γ-radiation, respectively. The current results reveal no effect of the donor gender on the sensitivity to γ-radiation. (author)

  4. Assessment of the radiation sensitivity of patients after conditioning irradiation as preparation for bone marrow or stem cell transplantation

    International Nuclear Information System (INIS)

    The knowledge on the radiation sensitivity of individual patients would allow a better planning of conditioning irradiation including the possibility of dose increase that might enhance the chance of a successful bone marrow or stem cell transplantation. The study was focused on the search of reliable and fast laboratory test procedures to predict the individual radiation sensitivity. Several blood tests were evaluated with respect to their appropriateness: mostly flow-cytometric test on lymphocytes: micronuclei, cell proliferation, apoptosis activation of cytokines and the total number of leucocytes, blood stem cells CD4+ and CD8+ lymphocytes, and a spectro-photometric test of blood plasma for the determination of the antioxidative capacity

  5. Study of the effects of sensitizer, radiation dose and leaching on the properties of irradiated field latex

    International Nuclear Information System (INIS)

    The effects of sensitizer, radiation dose and leaching on the properties of irradiated natural rubber field latex have been studied. Carbon tetrachloride, carbon tetrachloride + n-butyl acrylate and n-butyl acrylate + hydrogen peroxide were used as sensitizer for radiation chemical reaction. Samples were irradiated at the dose rate of 13-14 kGy/hr with 1480 TBq 60Co gamma source at room temperature. The samples were leached at various leaching conditions. Tensile strength, gel fraction, permanent set, swelling ratio, crosslinking density etc were measured by standard methods. (author). 18 refs., 8 tabs

  6. Cell Cycle Control and Adhesion Molecule Expression in Cells of the Immune System are Sensitive to Altered Gravity

    Science.gov (United States)

    Ullrich, O.; Paulsen, K.; Thiel, C.; Herrmann, K.; Sang, C.; Han, G.; Hemmersbach, R.; von der Wiesche, M.; Kroll, H.; Zhuang, F.; Grote, K. H.; Cogoli, A.; Zipp, F.; Engelmann, F.

    2008-06-01

    Life on earth developed in the presence and under the constant influence of gravity. Thus, it is a fundamental biological question, whether gravity is required for cellular functions and signal transduction in mammalian cells. Since the first Spacelab-Mission 20 years ago, it is known that activation and function of T lymphocytes is severely suppressed in microgravity, but the underlying molecular mechanisms are not elucidated. Experiments have been performed using ground-based facilities such as fast-rotating clinostat and hyper-g-centrifuges, and real microgravity provided by parabolic flights. We found that 1.) cells of the immune system responded cell type specifically to altered gravity, 2.) microgravity induced a multitude of initial alterations in signal transduction, whereas 3.) hypergravity of 1.8g did not induce any changes of the pathways tested, and that 4.) most of the initially altered pathways in microgravity adapted to "normal" levels within 15min. However, some pathways remained altered and could explain cell cycle arrest of T lymphocytes as observed in several long-term space experiments.

  7. Genomic alterations in BCL2L1 and DLC1 contribute to drug sensitivity in gastric cancer.

    Science.gov (United States)

    Park, Hansoo; Cho, Sung-Yup; Kim, Hyerim; Na, Deukchae; Han, Jee Yun; Chae, Jeesoo; Park, Changho; Park, Ok-Kyoung; Min, Seoyeon; Kang, Jinjoo; Choi, Boram; Min, Jimin; Kwon, Jee Young; Suh, Yun-Suhk; Kong, Seong-Ho; Lee, Hyuk-Joon; Liu, Edison T; Kim, Jong-Il; Kim, Sunghoon; Yang, Han-Kwang; Lee, Charles

    2015-10-01

    Gastric cancer (GC) is the third leading cause of cancer-related deaths worldwide. Recent high-throughput analyses of genomic alterations revealed several driver genes and altered pathways in GC. However, therapeutic applications from genomic data are limited, largely as a result of the lack of druggable molecular targets and preclinical models for drug selection. To identify new therapeutic targets for GC, we performed array comparative genomic hybridization (aCGH) of DNA from 103 patients with GC for copy number alteration (CNA) analysis, and whole-exome sequencing from 55 GCs from the same patients for mutation profiling. Pathway analysis showed recurrent alterations in the Wnt signaling [APC, CTNNB1, and DLC1 (deleted in liver cancer 1)], ErbB signaling (ERBB2, PIK3CA, and KRAS), and p53 signaling/apoptosis [TP53 and BCL2L1 (BCL2-like 1)] pathways. In 18.4% of GC cases (19/103), amplification of the antiapoptotic gene BCL2L1 was observed, and subsequently a BCL2L1 inhibitor was shown to markedly decrease cell viability in BCL2L1-amplified cell lines and in similarly altered patient-derived GC xenografts, especially when combined with other chemotherapeutic agents. In 10.9% of cases (6/55), mutations in DLC1 were found and were also shown to confer a growth advantage for these cells via activation of Rho-ROCK signaling, rendering these cells more susceptible to a ROCK inhibitor. Taken together, our study implicates BCL2L1 and DLC1 as potential druggable targets for specific subsets of GC cases. PMID:26401016

  8. Sensitivities to monochromatic 254-nm and 365-nm radiation of closely related strains of Saccharomyces cerevisiae with differing repair capabilities

    International Nuclear Information System (INIS)

    Sensitivity to monochromatic 254- and 365-nm radiation was compared in closely related yeast strains with defects in one or more of the excision-repair (rad1), error-prone repair (rad18), or recombinational-repair (rad51) pathways. At 254 nm, mutants defective in a single repair pathway exhibited slight to moderate UV sensitivity;,those defective in two separate pathways were somewhat more UV sensitive, while triple mutants defective in all three pathways exhibited extreme UV sensitivity with a lethal event corresponding to 0.05 J m-2. Repair defects also rendered mutants sensitive to 365-nm radiation: strains with single defects exhibited slight sensitivity, mutants with two defective pathways were more sensitive, and triple mutants exhibited maximal sensitivity with a lethal event corresponding to 2.4 x 104 J m-2. Evidence for dimer involvement in the yeast mutant was obtained by demonstrating that lethality at both 254 and 365 nm was photoreactivated by light at 405 nm. (author)

  9. Positron emission tomography (PET) study of the alterations in brain distribution of [11C]dethamphetamine in methamphetamine sensitized dog

    International Nuclear Information System (INIS)

    [11C]Methamphetamine ([11C]MAP) was synthesized by an automated on-line [11C]methylation system for positron emission tomography (PET) study. We newly produced a MAP sensitized dog by repeated MAP treatment and studied the brain distribution of [11C]MAP in the normal and the MAP sensitized dog. The maximal level of accumulation of [11C]MAP in the sensitized dog brain was 1.4 times higher than that in the control. No difference was found in the metabolism of MAP between the two conditions. The significant increase of [11C]MAP in the MAP sensitized brain indicates that subchronic MAP administration causes some functional change in uptake site of MAP

  10. Sensitivity analysis of performance of crop growth simulation models to daily solar radiation estimation methods in Iran

    Energy Technology Data Exchange (ETDEWEB)

    Farhadi Bansouleh, B. [International Institute for Geo-Information Science and Earth Observation (ITC), P.O. Box 6, 7500 AA Enschede (Netherlands); Water Engineering Department, Faculty of Agriculture, Razi University, Kermanshah (Iran); Sharifi, M.A. [International Institute for Geo-Information Science and Earth Observation (ITC), P.O. Box 6, 7500 AA Enschede (Netherlands); Van Keulen, H. [Plant Production Systems Group, Wageningen University, P.O. Box 430, 6700 AK Wageningen (Netherlands); Plant Research International, Wageningen University and Research Centre, P.O. Box 16, 6700 AA Wageningen (Netherlands)

    2009-11-15

    Solar radiation is the single most important environmental factor driving canopy photosynthesis and transpiration. This weather characteristic is measured only in a limited number of weather stations. Hence, in many situations it has to be estimated from other weather characteristics such as sunshine duration and temperature using empirical relations. In this study, the Aangstrom and Hargreaves formulas have been used for solar radiation estimation, based on monthly and annual weather data for three weather stations in Esfahan province, Iran. Deviations of estimated solar radiation from measured values (both absolute and relative) varied with month of the year and with estimation method. Estimated and measured radiation values were used in a crop growth simulation model to explore sensitivity of simulated production with respect to radiation estimation method. Maximum deviation for winter barley and silage maize was around 9%. (author)

  11. microRNA Alterations Driving Acute and Late Stages of Radiation-Induced Fibrosis in a Murine Skin Model

    Energy Technology Data Exchange (ETDEWEB)

    Simone, Brittany A. [Department of Radiation Oncology, Kimmel Cancer Center, Jefferson Medical College of Thomas Jefferson University Hospital, Philadelphia, Pennsylvania (United States); Ly, David; Savage, Jason E. [Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States); Hewitt, Stephen M. [Department of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States); Dan, Tu D. [Department of Radiation Oncology, Kimmel Cancer Center, Jefferson Medical College of Thomas Jefferson University Hospital, Philadelphia, Pennsylvania (United States); Ylaya, Kris [Department of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States); Shankavaram, Uma [Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States); Lim, Meng; Jin, Lianjin [Department of Radiation Oncology, Kimmel Cancer Center, Jefferson Medical College of Thomas Jefferson University Hospital, Philadelphia, Pennsylvania (United States); Camphausen, Kevin [Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States); Mitchell, James B. [Radiation Biology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States); Simone, Nicole L., E-mail: nicole.simone@jeffersonhospital.org [Department of Radiation Oncology, Kimmel Cancer Center, Jefferson Medical College of Thomas Jefferson University Hospital, Philadelphia, Pennsylvania (United States)

    2014-09-01

    Purpose: Although ionizing radiation is critical in treating cancer, radiation-induced fibrosis (RIF) can have a devastating impact on patients' quality of life. The molecular changes leading to radiation-induced fibrosis must be elucidated so that novel treatments can be designed. Methods and Materials: To determine whether microRNAs (miRs) could be responsible for RIF, the fibrotic process was induced in the right hind legs of 9-week old CH3 mice by a single-fraction dose of irradiation to 35 Gy, and the left leg served as an unirradiated control. Fibrosis was quantified by measurements of leg length compared with control leg length. By 120 days after irradiation, the irradiated legs were 20% (P=.013) shorter on average than were the control legs. Results: Tissue analysis was done on muscle, skin, and subcutaneous tissue from irradiated and control legs. Fibrosis was noted on both gross and histologic examination by use of a pentachrome stain. Microarrays were performed at various times after irradiation, including 7 days, 14 days, 50 days, 90 days, and 120 days after irradiation. miR-15a, miR-21, miR-30a, and miR-34a were the miRs with the most significant alteration by array with miR-34a, proving most significant on confirmation by reverse transcriptase polymerase chain reaction, c-Met, a known effector of fibrosis and downstream molecule of miR-34a, was evaluated by use of 2 cell lines: HCT116 and 1522. The cell lines were exposed to various stressors to induce miR changes, specifically ionizing radiation. Additionally, in vitro transfections with pre-miRs and anti-miRs confirmed the relationship of miR-34a and c-Met. Conclusions: Our data demonstrate an inverse relationship with miR-34a and c-Met; the upregulation of miR-34a in RIF causes inhibition of c-Met production. miRs may play a role in RIF; in particular, miR-34a should be investigated as a potential target to prevent or treat this devastating side effect of irradiation.

  12. microRNA Alterations Driving Acute and Late Stages of Radiation-Induced Fibrosis in a Murine Skin Model

    International Nuclear Information System (INIS)

    Purpose: Although ionizing radiation is critical in treating cancer, radiation-induced fibrosis (RIF) can have a devastating impact on patients' quality of life. The molecular changes leading to radiation-induced fibrosis must be elucidated so that novel treatments can be designed. Methods and Materials: To determine whether microRNAs (miRs) could be responsible for RIF, the fibrotic process was induced in the right hind legs of 9-week old CH3 mice by a single-fraction dose of irradiation to 35 Gy, and the left leg served as an unirradiated control. Fibrosis was quantified by measurements of leg length compared with control leg length. By 120 days after irradiation, the irradiated legs were 20% (P=.013) shorter on average than were the control legs. Results: Tissue analysis was done on muscle, skin, and subcutaneous tissue from irradiated and control legs. Fibrosis was noted on both gross and histologic examination by use of a pentachrome stain. Microarrays were performed at various times after irradiation, including 7 days, 14 days, 50 days, 90 days, and 120 days after irradiation. miR-15a, miR-21, miR-30a, and miR-34a were the miRs with the most significant alteration by array with miR-34a, proving most significant on confirmation by reverse transcriptase polymerase chain reaction, c-Met, a known effector of fibrosis and downstream molecule of miR-34a, was evaluated by use of 2 cell lines: HCT116 and 1522. The cell lines were exposed to various stressors to induce miR changes, specifically ionizing radiation. Additionally, in vitro transfections with pre-miRs and anti-miRs confirmed the relationship of miR-34a and c-Met. Conclusions: Our data demonstrate an inverse relationship with miR-34a and c-Met; the upregulation of miR-34a in RIF causes inhibition of c-Met production. miRs may play a role in RIF; in particular, miR-34a should be investigated as a potential target to prevent or treat this devastating side effect of irradiation

  13. Alterations in whole-body insulin sensitivity resulting from repeated eccentric exercise of a single muscle group: a pilot investigation

    OpenAIRE

    Gonzalez, Javier; Barwood, Martin; Goodall, Stuart; Thomas, Kevin; Howatson, Glyn

    2015-01-01

    Unaccustomed eccentric exercise using large muscle groups elicits soreness, decrements in physical function and impairs markers of whole-body insulin sensitivity; although these effects are attenuated with a repeated exposure. Eccentric exercise of a small muscle group (elbow flexors) displays similar soreness and damage profiles in response to repeated exposure. However, it is unknown whether damage to small muscle groups impacts upon whole-body insulin sensitivity. This pilot investigation ...

  14. Investigation of the modifying effects of vitamin A and hypoxic cell sensitizers in radiation carcinogenesis in mice

    International Nuclear Information System (INIS)

    The effect of vitamin A (retinyl acetate) and three hypoxic cell sensitizers (metronidazole, misonidazole and desmethylmisonidazole) on lung tumor development in strain A mice exposed to radiation was assessed. In experiments involving vitamin A, two groups of mice were fed a low vitamin A diet (< 100 IU/100g diet) while the two other groups were fed a high vitamin A diet (800 IU/100 g diet). After two weeks one group maintained on the high vitamin A diet and one group maintained on the low vitamin A diet were given an acute dose of 500 rad of gamma radiation to the thoracic region. Mice were killed, their lungs were removed and the number of surface adenomas were counted. There was a significant increase in the number of mice bearing lung tumors and the mean number of lung tumors per mouse in the irradiated group maintained on the high vitamin A diet at 40 weeks post irradiation as compared to the irradiated group maintained on a low vitamin A diet. In the other experiment two dose levels of the hypoxic cell sensitizers, 0.2 mg/g and 0.6 mg/g, were used either alone or in combination with 900 rad of gamma radiation in a fractionated dose schedule of twice a week for three weeks. In the groups of mice which received hypoxic cell sensitizers only, the prevalence and the mean number of lung tumors per mouse were somewhat increased in the higher dose group (0.6 mg/g) of misonidazole but was not significantly different from the control animals in the other two sensitizer groups. The combination of hypoxic cell sensitizer and radiation did not show any significant enhancement of lung tumor response when compared with the group which received radiation only. The dose of radiation used in this study significantly enhanced lung tumor formation in mice when compared with the control group

  15. The L84F polymorphic variant of human O6-methylguanine-DNA methyltransferase alters stability in U87MG glioma cells but not temozolomide sensitivity

    OpenAIRE

    Remington, Maya; Chtchetinin, Jana; Ancheta, Karen; Nghiemphu, Phioanh Leia; Cloughesy, Timothy; Lai, Albert

    2009-01-01

    First-line therapy for patients with glioblastoma multiforme includes treatment with radiation and temozolomide (TMZ), an oral DNA alkylating chemotherapy. Sensitivity of glioma cells to TMZ is dependent on the level of cellular O6-methylguanine-DNA methyltransferase (MGMT) repair activity. Several common coding- region polymorphisms in the MGMT gene (L84F and the linked pair I143V/K178R) modify functional characteristics of MGMT and cancer risk. To determine whether these polymorphic changes...

  16. Proinflammatory and Th1 cytokine alterations following ultraviolet radiation enhancement of disease due to influenza infection in mice.

    Science.gov (United States)

    Ryan, Lisa K; Copeland, Lisa R; Daniels, Mary J; Costa, Elisabeth R; Selgrade, Mary Jane K

    2002-05-01

    Exposure of rodents to immunosuppressive agents such as ozone, dioxin, or ultraviolet radiation (UVR) leads to increased morbidity and mortality following influenza virus infection. However, these adverse effects are not related to the suppression of virus-specific immune responses. Our laboratory showed that UVR increased the morbidity, mortality, and pathogenesis of influenza virus without affecting protective immunity to the virus, as measured by resistance to reinfection, suggesting that UVR and other immunosuppressive pollutants such as dioxin and ozone may exacerbate early responses that contribute to the pathogenesis of a primary viral infection. In the present study, we examined the mechanism of UVR-enhanced mortality in the absence of effects on virus-specific immunity and tested the hypothesis that modulation of cytokine levels was associated with increased deaths and body weight loss. BALB/c mice were exposed to 8.2 kJ/m(2) UVR and were infected 3 days later with a sublethal influenza virus infection (LD(40) of mouse-adapted Hong Kong influenza A/68, H(3)N(2)). Influx of inflammatory cells, proinflammatory cytokines, and cytokines produced by T-helper lymphocytes (Th1 and Th2) were measured in lung homogenates (LH) as well as in bronchoalveolar lavage fluid (BAL). UVR preexposure decreased the influenza-induced lymphocytic influx 5 days after infection, but did not alter macrophage and neutrophil influx into the lung, or increase virus titers significantly. Although interferon (IFN)-gamma, total interleukin (IL)-12, IL-6, and TNF-alpha were altered in mice that received UVR exposure prior to infection, no clear association was made that correlated with the UVR-induced increase in body weight loss and mortality due to influenza infection. PMID:11961220

  17. Rearrangement of RAG-1 recombinase gene in radiation-sensitive ''wasted'' mice

    International Nuclear Information System (INIS)

    Mice recessive for the autosomal gene ''wasted'' (wst) display a disease pattern which includes increased sensitivity to the killing effects of ionizing radiation, immunodeficiency, and neurologic dysfunction. The recent cloning and characterization of recombinase genes (RAG-1/RAG-2) expressed in lymphoid and possibly central nervous system tissues prompted us to examine expression of these genes in DNA repair-deficient/immunodeficient wasted mice. Our results revealed expression of RAG-1 mRNA in spinal cord (but not brain) of control mice; no expression of RAG-1 mRNA was detected in spinal cord or brain from wst/wst mice or their normal littermates (wst/· mice). In thymus tissue, a small RAG-1 transcript (1.0 kb) was detected in wst/wst mice that was not evident in thymus from control mice. In wst/· mice, a two-fold increase in RAG-1 MRNA was evident in thymus tissue. RAG-2 mRNA could only be detected in thymus tissue from wst/· and not from wst/wst or parental control BCF1 mice. Southern blots revealed a rearrangement/deletion within the RAG-1 gene of affected wasted mice, not evident in known strain-specific parental or littermate controls. These results support the idea that the RAG-1 gene may map at or near the locus for the wasted mutation. In addition, they suggest the importance of recombinase function in normal immune and central nervous system development as well as the potential contribution of this gene family to the normal repair of radiation-induced DNA damage

  18. Solar Load Inputs for USARIEM Thermal Strain Models and the Solar Radiation-Sensitive Components of the WBGT Index

    Science.gov (United States)

    Matthew, William T.; Santee, William R.; Berglund, Larry G.

    2001-06-01

    This report describes processes we have implemented to use global pyranometer-based estimates of mean radiant temperature as the common solar load input for the Scenario model, the USARIEM heat strain model, and for the computation of the solar radiation sensitive components of the Wet Bulb Globe Temperature (WBGT) index.

  19. C/EBPδ Deficiency Sensitizes Mice to Ionizing Radiation-Induced Hematopoietic and Intestinal Injury

    OpenAIRE

    Pawar, Snehalata A.; Shao, Lijian; Chang, Jianhui; Wang, Wenze; Pathak, Rupak; Zhu, Xiaoyan; Wang, Junru; Hendrickson, Howard; Boerma, Marjan; Sterneck, Esta; Zhou, Daohong; Hauer-Jensen, Martin

    2014-01-01

    Knowledge of the mechanisms involved in the radiation response is critical for developing interventions to mitigate radiation-induced injury to normal tissues. Exposure to radiation leads to increased oxidative stress, DNA-damage, genomic instability and inflammation. The transcription factor CCAAT/enhancer binding protein delta (Cebpd; C/EBPδ is implicated in regulation of these same processes, but its role in radiation response is not known. We investigated the role of C/EBPδ in radiation-i...

  20. Effects of thermal sensitization on radiation-induced segregation in type 304 stainless steel irradiated with He-ions

    International Nuclear Information System (INIS)

    Type 304 stainless steels, solution-annealed and thermally sensitized at 923 K for 0.5 to 24 h, were He-ion-irradiated up to about 4 dpa at 723 K and radiation-induced segregation (RIS) at grain boundaries was measured by EDS analysis using a FEG-TEM. Ni, Si and P were enriched, and Cr was depleted at the grain boundaries by irradiation. However, although the irradiation dose was the same for the specimens, the RIS of the elements linearly increased with the logarithm of the thermally sensitizing time, except for Cr in the specimen thermally sensitized for 24 h. The enhancement of RIS was attributed to the radiation-induced point defects having large mobility in thermally sensitized stainless steels, because of an expected decrease in C near the grain boundaries and in the matrix after the sensitization heat treatments. It was clarified by the electrochemical potentiokinetic reactivation test (EPR) that the degree of sensitization increased with the progress of Cr depletion at grain boundaries. The Cr concentration at grain boundaries in the heavily sensitized specimen was not changed, and the width of the depleted area was slightly narrowed by the irradiation. This result could be explained that the diffusion of Cr due to initial Cr concentration gradient near grain boundaries exceeded the inverse Kirkendall effect. (orig.)

  1. Effect of end-of-day far-red light exposures on fertility alteration and flowering in photoperiod-sensitive genic male-sterile rice

    International Nuclear Information System (INIS)

    The rice photoperiod-sensitive genic male-sterile mutant (PGMR) is sterile under long days, but fertile in short days. Phytochrome is involved in the photoperiod-induced male-sterile process. To investigate the mechanisms, of phytochrome action in PGMR, end-of-day (EOD) experiments were carried out. Flowering in PGMR was delayed considerably by EOD far-red light exposures following a short day of 10 hr, whereas its fertility decreased to the same extent as the original line. This result suggests that photoperiod response mediating fertility alteration in PGMR somewhat differed from that in flowering,i.e., fertility alteration and flowering might be under the separate phytochrome signaling control. (author)

  2. Relationship Between Chromatin Structure and Sensitivity to Molecularly Targeted Auger Electron Radiation Therapy

    International Nuclear Information System (INIS)

    Purpose: The open structure of euchromatin renders it susceptible to DNA damage by ionizing radiation (IR) compared with compact heterochromatin. The effect of chromatin configuration on the efficacy of Auger electron radiotherapy was investigated. Methods and Materials: Chromatin structure was altered in MDA-MB-468 and 231-H2N human breast cancer cells by suberoylanilide hydroxamic acid (SAHA), 5-aza-2-deoxycytidine, or hypertonic treatment. The extent and duration of chromatin structural changes were evaluated using the micrococcal nuclease assay. DNA damage (γH2AX assay) and clonogenic survival were evaluated after exposure to 111In-DTPA-hEGF, an Auger electron-emitting radiopharmaceutical, or IR. The intracellular distribution of 111In-DTPA-hEGF after chromatin modification was investigated in cell fractionation experiments. Results: Chromatin remained condensed for up to 20 minutes after NaCl and in a relaxed state 24 hours after SAHA treatment. The number of γH2AX foci per cell was greater in MDA-MB-468 and 231-H2N cells after IR (0.5 Gy) plus SAHA (1 μM) compared with IR alone (16 ± 0.6 and 14 ± 0.3 vs. 12 ± 0.4 and 11 ± 0.2, respectively). More γH2AX foci were observed in MDA-MB-468 and 231-H2N cells exposed to 111In-DTPA-hEGF (6 MBq/μg) plus SAHA vs. 111In-DTPA-hEGF alone (11 ± 0.3 and 12 ± 0.7 vs. 9 ± 0.4 and 7 ± 0.3, respectively). 5-aza-2-deoxycytidine enhanced the DNA damage caused by IR and 111In-DTPA-hEGF. Clonogenic survival was reduced in MDA-MB-468 and 231-H2N cells after IR (6 Gy) plus SAHA (1 μM) vs. IR alone (0.6% ± 0.01 and 0.3% ± 0.2 vs. 5.8% ± 0.2 and 2% ± 0.1, respectively) and after 111In-DTPA-hEGF plus SAHA compared to 111In-DTPA-hEGF alone (21% ± 0.4% and 19% ± 4.6 vs. 33% ± 2.3 and 32% ± 3.7). SAHA did not affect 111In-DTPA-hEGF nuclear localization. Hypertonic treatment resulted in fewer γH2AX foci per cell after IR and 111In-DTPA-hEGF compared to controls but did not significantly alter clonogenic survival

  3. Analysis of the common deletions in the mitochondrial DNA is a sensitive biomarker detecting direct and non-targeted cellular effects of low dose ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Schilling-Toth, Boglarka; Sandor, Nikolett; Kis, Eniko [Department of Molecular and Tumor Radiobiology, Frederic Joliot-Curie National Research Institute for Radiobiology and Radiohygiene, Anna u 5, H-1221 Budapest (Hungary); Kadhim, Munira [Genomic Instability Research Group, School of Life Sciences, Oxford Brookes University, Oxford OX3 0BP (United Kingdom); Safrany, Geza, E-mail: safrany.geza@osski.hu [Department of Molecular and Tumor Radiobiology, Frederic Joliot-Curie National Research Institute for Radiobiology and Radiohygiene, Anna u 5, H-1221 Budapest (Hungary); Hegyesi, Hargita [Department of Molecular and Tumor Radiobiology, Frederic Joliot-Curie National Research Institute for Radiobiology and Radiohygiene, Anna u 5, H-1221 Budapest (Hungary)

    2011-11-01

    One of the key issues of current radiation research is the biological effect of low doses. Unfortunately, low dose science is hampered by the unavailability of easily performable, reliable and sensitive quantitative biomarkers suitable detecting low frequency alterations in irradiated cells. We applied a quantitative real time polymerase chain reaction (qRT-PCR) based protocol detecting common deletions (CD) in the mitochondrial genome to assess direct and non-targeted effects of radiation in human fibroblasts. In directly irradiated (IR) cells CD increased with dose and was higher in radiosensitive cells. Investigating conditioned medium-mediated bystander effects we demonstrated that low and high (0.1 and 2 Gy) doses induced similar levels of bystander responses and found individual differences in human fibroblasts. The bystander response was not related to the radiosensitivity of the cells. The importance of signal sending donor and signal receiving target cells was investigated by placing conditioned medium from a bystander response positive cell line (F11-hTERT) to bystander negative cells (S1-hTERT) and vice versa. The data indicated that signal sending cells are more important in the medium-mediated bystander effect than recipients. Finally, we followed long term effects in immortalized radiation sensitive (S1-hTERT) and normal (F11-hTERT) fibroblasts up to 63 days after IR. In F11-hTERT cells CD level was increased until 35 days after IR then reduced back to control level by day 49. In S1-hTERT cells the increased CD level was also normalized by day 42, however a second wave of increased CD incidence appeared by day 49 which was maintained up to day 63 after IR. This second CD wave might be the indication of radiation-induced instability in the mitochondrial genome of S1-hTERT cells. The data demonstrated that measuring CD in mtDNA by qRT-PCR is a reliable and sensitive biomarker to estimate radiation-induced direct and non-targeted effects.

  4. Analysis of the common deletions in the mitochondrial DNA is a sensitive biomarker detecting direct and non-targeted cellular effects of low dose ionizing radiation.

    Science.gov (United States)

    Schilling-Tóth, Boglárka; Sándor, Nikolett; Kis, Eniko; Kadhim, Munira; Sáfrány, Géza; Hegyesi, Hargita

    2011-11-01

    One of the key issues of current radiation research is the biological effect of low doses. Unfortunately, low dose science is hampered by the unavailability of easily performable, reliable and sensitive quantitative biomarkers suitable detecting low frequency alterations in irradiated cells. We applied a quantitative real time polymerase chain reaction (qRT-PCR) based protocol detecting common deletions (CD) in the mitochondrial genome to assess direct and non-targeted effects of radiation in human fibroblasts. In directly irradiated (IR) cells CD increased with dose and was higher in radiosensitive cells. Investigating conditioned medium-mediated bystander effects we demonstrated that low and high (0.1 and 2Gy) doses induced similar levels of bystander responses and found individual differences in human fibroblasts. The bystander response was not related to the radiosensitivity of the cells. The importance of signal sending donor and signal receiving target cells was investigated by placing conditioned medium from a bystander response positive cell line (F11-hTERT) to bystander negative cells (S1-hTERT) and vice versa. The data indicated that signal sending cells are more important in the medium-mediated bystander effect than recipients. Finally, we followed long term effects in immortalized radiation sensitive (S1-hTERT) and normal (F11-hTERT) fibroblasts up to 63 days after IR. In F11-hTERT cells CD level was increased until 35 days after IR then reduced back to control level by day 49. In S1-hTERT cells the increased CD level was also normalized by day 42, however a second wave of increased CD incidence appeared by day 49 which was maintained up to day 63 after IR. This second CD wave might be the indication of radiation-induced instability in the mitochondrial genome of S1-hTERT cells. The data demonstrated that measuring CD in mtDNA by qRT-PCR is a reliable and sensitive biomarker to estimate radiation-induced direct and non-targeted effects. PMID:21843534

  5. Analysis of the common deletions in the mitochondrial DNA is a sensitive biomarker detecting direct and non-targeted cellular effects of low dose ionizing radiation

    International Nuclear Information System (INIS)

    One of the key issues of current radiation research is the biological effect of low doses. Unfortunately, low dose science is hampered by the unavailability of easily performable, reliable and sensitive quantitative biomarkers suitable detecting low frequency alterations in irradiated cells. We applied a quantitative real time polymerase chain reaction (qRT-PCR) based protocol detecting common deletions (CD) in the mitochondrial genome to assess direct and non-targeted effects of radiation in human fibroblasts. In directly irradiated (IR) cells CD increased with dose and was higher in radiosensitive cells. Investigating conditioned medium-mediated bystander effects we demonstrated that low and high (0.1 and 2 Gy) doses induced similar levels of bystander responses and found individual differences in human fibroblasts. The bystander response was not related to the radiosensitivity of the cells. The importance of signal sending donor and signal receiving target cells was investigated by placing conditioned medium from a bystander response positive cell line (F11-hTERT) to bystander negative cells (S1-hTERT) and vice versa. The data indicated that signal sending cells are more important in the medium-mediated bystander effect than recipients. Finally, we followed long term effects in immortalized radiation sensitive (S1-hTERT) and normal (F11-hTERT) fibroblasts up to 63 days after IR. In F11-hTERT cells CD level was increased until 35 days after IR then reduced back to control level by day 49. In S1-hTERT cells the increased CD level was also normalized by day 42, however a second wave of increased CD incidence appeared by day 49 which was maintained up to day 63 after IR. This second CD wave might be the indication of radiation-induced instability in the mitochondrial genome of S1-hTERT cells. The data demonstrated that measuring CD in mtDNA by qRT-PCR is a reliable and sensitive biomarker to estimate radiation-induced direct and non-targeted effects.

  6. Individual sensitivity to radiations and DNA repair proficiency: the comet assay contribution

    International Nuclear Information System (INIS)

    Some are hereditary syndromes demonstrate high cancer risk and hypersensitivity in response to exposures to agents such as ultraviolet or ionising radiation, and are characterized by a defective processing of DNA damage. They highlight the importance of the individual risk associated to exposures. The comet assay, a simple technique that detects DNA strand breaks, requires few cells and allows examination of DNA repair capacities in established cell lines, in blood samples or biopsies. The assay has been validated on cellular systems with known repair defects such as xeroderma pigmentosum defective in nucleotide excision repair, on mutant rodent cell lines defective in DNA single strand breaks rejoining (XRCC5/Ku80 and XRCC7/DNAPKcs) (neutral conditions). This assay does not allow to distinguish a defective phenotype in ataxia telangiectasia cells. It shows in homozygous mouse embryo fibroblasts Brca2-/- an impaired DNA double strand break rejoining. Simplicity, rapidity and sensitivity of the alkaline comet assay allow to examine the response of lymphocytes. It has been applied to the analysis of the role of DNA repair in the pathogenesis of collagen diseases, and the involvement of individual DNA repair proficiency in the thyroid tumorigenesis induced in some patients after therapeutic irradiation at childhood has been questioned. Preliminary results of these studies suggest that this type of approach could help for adapting treatment modalities and surveillance in subgroups of patients defective in DNA repair process. It could also have some incidence in the radioprotection field. (author)

  7. Carboxymethyl starch cross-linked by electron beam radiation in presence of acrylic acid sensitizer

    International Nuclear Information System (INIS)

    Carboxymethyl starch (CMS) can be cross-linked by electron beam radiation to form a biocompatible and environment-friendly hydrogel at a high absorbed dose and a condensed CMS concentration. Acrylic acid (AAc) can be used as a sensitizer in order to reduce the absorbed doses to an acceptable certain level. At an absorbed dose of 3-4 kGy, the gel content of crosslinked CMS can be obtained about 50% with 5% (w/w) AAc concentration used. The compressive strength of CMS samples increased with increasing their cross-linked densities due to raising absorbed doses. The swelling ratio of cross-linked CMS was also attainable at a maximum of 50 times in the distilled water. The enzymatic degradation of cross-linked CMS was carried out in acetate buffer pH 4.6 with 0.1% α-amylase enzymatic solution incubated at 40℃ for 6 h. The crosslinked CMS samples were degraded slower than uncrosslinked CMS ones. The results indicated that the highly cross-linked CMS was almost fully degradable when the enzymatic hydrolysis was performed during 6 h. The FT IR spectra of cross-linked CMS in the presence of AAc were examined to observe the carboxyl group of AAc in the structure of cross-linked CMS. The hydrophilic of cross-linked CMS surface was determined by a contact-angle analysis. (authors)

  8. Radioresistant DNA synthesis in cells of patients showing increased chromosomal sensitivity to ionizing radiation

    International Nuclear Information System (INIS)

    The rate of DNA synthesis after γ-irradiation was studied either by analysis of the steady-state distribution of daughter [3H]DNA in alkaline sucrose gradients or by direct assay of the amount of [3H]thymidine incorporated into DNA of fibroblasts derived from a normal donor (LCH882) and from Down's syndrome (LCH944), Werner's syndrome (WS1LE) and xeroderma pigmentosum (XP2LE) patients with chromosomal sensitivity to ionizing radiation. Doses of γ-irradiation that markedly inhibited the rate of DNA synthesis in normal human cells caused almost no inhibition of DNA synthesis in the cells from the affected individuals. The radioresistant DNA synthesis in Down's syndrome cells was mainly due to a much lower inhibition of replicon initiation than that in normal cells; these cells were also more resistant to damage that inhibited replicon elongation. Our data suggest that radioresistant DNA synthesis may be an intrinsic feature of all genetic disorders showing increased radiosensitivity in terms of chromosome aberrations. (orig.)

  9. Arsenic trioxide enhances the radiation sensitivity of androgen-dependent and -independent human prostate cancer cells.

    Directory of Open Access Journals (Sweden)

    Hui-Wen Chiu

    Full Text Available Prostate cancer is the most common malignancy in men. In the present study, LNCaP (androgen-sensitive human prostate cancer cells and PC-3 cells (androgen-independent human prostate cancer cells were used to investigate the anti-cancer effects of ionizing radiation (IR combined with arsenic trioxide (ATO and to determine the underlying mechanisms in vitro and in vivo. We found that IR combined with ATO increases the therapeutic efficacy compared to individual treatments in LNCaP and PC-3 human prostate cancer cells. In addition, combined treatment showed enhanced reactive oxygen species (ROS generation compared to treatment with ATO or IR alone in PC-3 cells. Combined treatment induced autophagy and apoptosis in LNCaP cells, and mainly induced autophagy in PC-3 cells. The cell death that was induced by the combined treatment was primarily the result of inhibition of the Akt/mTOR signaling pathways. Furthermore, we found that the combined treatment of cells pre-treated with 3-MA resulted in a significant change in AO-positive cells and cytotoxicity. In an in vivo study, the combination treatment had anti-tumor growth effects. These novel findings suggest that combined treatment is a potential therapeutic strategy not only for androgen-dependent prostate cancer but also for androgen-independent prostate cancer.

  10. Sensitivity of Roberts Syndrome Cells to gamma radiation, mitomycin C, and protein synthesis inhibitors

    International Nuclear Information System (INIS)

    Roberts syndrome (RS) is a rare autosomal recessive disorder characterized by pre- and postnatal growth retardation, limb reduction abnormalities, and craniofacial anomalies. Mitotic chromosomes from RS individuals display repulsion of heterochromatin regions or centromere splitting, leading to a railroad-track appearance of mitotic chromosomes. Abnormalities in metaphase duration, anaphase progression, nuclear morphology, and increased frequency of micronucleation have been reported in RS cells. Cells from RS heterozygotes are normal in these respects, and in vitro complementation of the defects in somatic cell hybrids has been reported. Therefore, in preparation for the isolation of cDNAs that complement the RS defect, the authors investigated various drug treatments to identify an agent that specifically involves the growth of RS cells. Based on the cytogenetic and cell biologic findings, they chose agents that increase micronucleation or inhibit protein synthesis. They found that RS cells are hypersensitive to gamma radiation, mitomycin C, G418 and hygromycin B, but not to colcemid or streptonigrin when compared to normal cells. DNA content and cell viability analysis confirmed that the sensitivity to gamma irradiation was primarily due to increased cell death

  11. Control of radiation sensitivity of mammalian cells. Regulation of expression of DNA repair genes

    International Nuclear Information System (INIS)

    This review describes authors' investigations concerning regulation of expression of DNA repair genes for the purpose of control of radiosensitivity of mammalian cells for cancer radiotherapy. One of their experiments concerns the enhancement of sensitivity to radiation and anti-tumor agents by suppressing the expression of mammalian Rad51 gene which playing a central role in recombination repair against DNA double-strand break, by RNA interference (RNAi). Described are the mode of action of RNAi, mechanism of suppression of Rad51 gene expression by it, enhancing effect in radiosensitivity, stable suppression and enhancement by hairpin RNA and its possible usefulness in cancer therapy. The other concerns the histone H2AX gene, which delivering the repair signal post phosphorylation in chromatin against the double-strand break. Experimental results of suppression of the histone H2AX gene by tet-off system, enhancement of radiosensitivity by the suppression and functional recovery by the gene transfer are described, and the radiosensitivity can be thus artificially controlled by tetracycline in authors' F9 2AX (tet/tet) cells. (N.I.)

  12. Silencing of poly(ADP-ribose) glycohydrolase sensitizes lung cancer cells to radiation through the abrogation of DNA damage checkpoint

    Energy Technology Data Exchange (ETDEWEB)

    Nakadate, Yusuke [Shien-Lab, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045 (Japan); Department of Bioengineering, Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan); Kodera, Yasuo; Kitamura, Yuka [Shien-Lab, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045 (Japan); Tachibana, Taro [Department of Bioengineering, Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan); Tamura, Tomohide [Division of Thoracic Oncology, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045 (Japan); Koizumi, Fumiaki, E-mail: fkoizumi@ncc.go.jp [Division of Thoracic Oncology, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045 (Japan)

    2013-11-29

    Highlights: •Radiosensitization by PARG silencing was observed in multiple lung cancer cells. •PAR accumulation was enhanced by PARG silencing after DNA damage. •Radiation-induced G2/M arrest and checkpoint activation were impaired by PARG siRNA. -- Abstract: Poly(ADP-ribose) glycohydrolase (PARG) is a major enzyme that plays a role in the degradation of poly(ADP-ribose) (PAR). PARG deficiency reportedly sensitizes cells to the effects of radiation. In lung cancer, however, it has not been fully elucidated. Here, we investigated whether PARG siRNA contributes to an increased radiosensitivity using 8 lung cancer cell lines. Among them, the silencing of PARG induced a radiosensitizing effect in 5 cell lines. Radiation-induced G2/M arrest was largely suppressed by PARG siRNA in PC-14 and A427 cells, which exhibited significantly enhanced radiosensitivity in response to PARG knockdown. On the other hand, a similar effect was not observed in H520 cells, which did not exhibit a radiosensitizing effect. Consistent with a cell cycle analysis, radiation-induced checkpoint signals were not well activated in the PC-14 and A427 cells when treated with PARG siRNA. These results suggest that the increased sensitivity to radiation induced by PARG knockdown occurs through the abrogation of radiation-induced G2/M arrest and checkpoint activation in lung cancer cells. Our findings indicate that PARG could be a potential target for lung cancer treatments when used in combination with radiotherapy.

  13. Combined changes in Wnt signaling response and contact inhibition induce altered proliferation in radiation-treated intestinal crypts.

    Science.gov (United States)

    Dunn, S-J; Osborne, J M; Appleton, P L; Näthke, I

    2016-06-01

    Curative intervention is possible if colorectal cancer is identified early, underscoring the need to detect the earliest stages of malignant transformation. A candidate biomarker is the expanded proliferative zone observed in crypts before adenoma formation, also found in irradiated crypts. However, the underlying driving mechanism for this is not known. Wnt signaling is a key regulator of proliferation, and elevated Wnt signaling is implicated in cancer. Nonetheless, how cells differentiate Wnt signals of varying strengths is not understood. We use computational modeling to compare alternative hypotheses about how Wnt signaling and contact inhibition affect proliferation. Direct comparison of simulations with published experimental data revealed that the model that best reproduces proliferation patterns in normal crypts stipulates that proliferative fate and cell cycle duration are set by the Wnt stimulus experienced at birth. The model also showed that the broadened proliferation zone induced by tumorigenic radiation can be attributed to cells responding to lower Wnt concentrations and dividing at smaller volumes. Application of the model to data from irradiated crypts after an extended recovery period permitted deductions about the extent of the initial insult. Application of computational modeling to experimental data revealed how mechanisms that control cell dynamics are altered at the earliest stages of carcinogenesis. PMID:27053661

  14. Mutations in the Plasmodium falciparum chloroquine resistance transporter, PfCRT, enlarge the parasite's food vacuole and alter drug sensitivities.

    Science.gov (United States)

    Pulcini, Serena; Staines, Henry M; Lee, Andrew H; Shafik, Sarah H; Bouyer, Guillaume; Moore, Catherine M; Daley, Daniel A; Hoke, Matthew J; Altenhofen, Lindsey M; Painter, Heather J; Mu, Jianbing; Ferguson, David J P; Llinás, Manuel; Martin, Rowena E; Fidock, David A; Cooper, Roland A; Krishna, Sanjeev

    2015-01-01

    Mutations in the Plasmodium falciparum chloroquine resistance transporter, PfCRT, are the major determinant of chloroquine resistance in this lethal human malaria parasite. Here, we describe P. falciparum lines subjected to selection by amantadine or blasticidin that carry PfCRT mutations (C101F or L272F), causing the development of enlarged food vacuoles. These parasites also have increased sensitivity to chloroquine and some other quinoline antimalarials, but exhibit no or minimal change in sensitivity to artemisinins, when compared with parental strains. A transgenic parasite line expressing the L272F variant of PfCRT confirmed this increased chloroquine sensitivity and enlarged food vacuole phenotype. Furthermore, the introduction of the C101F or L272F mutation into a chloroquine-resistant variant of PfCRT reduced the ability of this protein to transport chloroquine by approximately 93 and 82%, respectively, when expressed in Xenopus oocytes. These data provide, at least in part, a mechanistic explanation for the increased sensitivity of the mutant parasite lines to chloroquine. Taken together, these findings provide new insights into PfCRT function and PfCRT-mediated drug resistance, as well as the food vacuole, which is an important target of many antimalarial drugs. PMID:26420308

  15. Evaluation of the radiation-sensitizer/protector and/or antioxidant efficiencies using Fricke and PAG dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Meesat, Ridthee; Jay-Gerin, Jean-Paul; Khalil, Abdelouahed; Lepage, Martin [Departement de medecine nucleaire et de radiobiologie, Faculte de medecine et des sciences de la sante, Universite de Sherbrooke, Sherbrooke (Quebec) J1H 5N4 (Canada)], E-mail: Martin.Lepage@USherbrooke.ca

    2009-05-01

    In this study, our aim is to assess the potential of Fricke and polyacrylamide gel (PAG) dosimeters to quantitatively evaluate the efficiency of potential radiation sensitizers/protectors and antioxidants. These compounds are of importance in radiotherapy as well as in disease prevention and promotion of health. The basic principle of the Fricke dosimeter is the radiation-induced oxidation of Fe{sup 2+} to Fe{sup 3+} in an aerated aqueous 0.4 M H{sub 2}SO{sub 4}. The production of ferric ions is most sensitive to the radical species produced in the radiolysis of water. Using this method, we observed that cystamine (one of the best of the known radioprotectors) can prevent oxydation of Fe{sup 2+} from reactive radiolysis species. However, one obvious disadvantage of the Fricke dosimeter is that it operates under highly acidic conditions (pH 0.46), which may degrade biological compounds. In contrast, the pH of the polyacrylamide gel (PAG) dosimeter is almost neutral, such that degradation of compounds is less probable. A change in R{sub 2}-dose sensitivity was observed in the presence of radiosensitizers/radioprotectors and antioxidants. The protective effect of Trolox (a well-known antioxidant) and thiourea (a radioprotector) was readily observed using the PAG dosimeter. Incorporation of iodinated radiation sensitizers such as NaI and an iodine contrast agent led to a quantifiable sensitizer enhancement ratio. These studies suggest that the Fricke and the PAG dosimeters have the potential to evaluate the efficiency of radiation sensitizers/protectors and antioxidants.

  16. Curcumin Sensitizes Hepatocellular Carcinoma Cells to Radiation via Suppression of Radiation-Induced NF-κB Activity

    Directory of Open Access Journals (Sweden)

    Fei-Ting Hsu

    2015-01-01

    Full Text Available The effects and possible underlying mechanism of curcumin combined with radiation in human hepatocellular carcinoma (HCC cells in vitro were evaluated. The effects of curcumin, radiation, and combination of both on cell viability, apoptosis, NF-κB activation, and expressions of NF-κB downstream effector proteins were investigated with 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT, NF-κB reporter gene, mitochondrial membrane potential (MMP, electrophoretic mobility shift (EMSA, and Western blot assays in Huh7-NF-κB-luc2, Hep3B, and HepG2 cells. Effect of I kappa B alpha mutant (IκBαM vector, a specific inhibitor of NF-κB activation, on radiation-induced loss of MMP was also evaluated. Results show that curcumin not only significantly enhances radiation-induced cytotoxicity and depletion of MMP but inhibits radiation-induced NF-κB activity and expressions of NF-κB downstream proteins in HCC cells. IκBαM vector also shows similar effects. In conclusion, we suggest that curcumin augments anticancer effects of radiation via the suppression of NF-κB activation.

  17. Evaluation of γ-radiation-induced DNA damage in two species of bivalves and their relative sensitivity using comet assay

    Energy Technology Data Exchange (ETDEWEB)

    Praveen Kumar, M.K., E-mail: here.praveen@gmail.com [Department of Zoology, Goa University, Goa 403206 (India); Shyama, S.K., E-mail: skshyama@gmail.com [Department of Zoology, Goa University, Goa 403206 (India); Sonaye, B.S. [Department of Radiation Oncology, Goa Medical College, Goa (India); Naik, U Roshini; Kadam, S.B.; Bipin, P.D.; D’costa, A. [Department of Zoology, Goa University, Goa 403206 (India); Chaubey, R.C. [Radiation Biology and Health Science Division, Bhabha Atomic Research Centre, Mumbai (India)

    2014-05-01

    Highlights: • Possible genotoxic effect of accidental exposure of aquatic fauna to γ radiation. • Relative sensitivity of bivalves to γ radiation is also analyzed using comet assay. • γ radiation induced significant genetic damage in both the species of bivalves. • P. malabarica and M. casta exhibited a similar level of sensitivity to γ radiation. • Comet assay may be used as a biomarker for the environmental biomonitoring. - Abstract: Ionizing radiation is known to induce genetic damage in diverse groups of organisms. Under accidental situations, large quantities of radioactive elements get released into the environment and radiation emitted from these radionuclides may adversely affect both the man and the non-human biota. The present study is aimed (a) to know the genotoxic effect of gamma radiation on aquatic fauna employing two species of selected bivalves, (b) to evaluate the possible use of ‘Comet assay’ for detecting genetic damage in haemocytes of bivalves as a biomarker for environmental biomonitoring and also (c) to compare the relative sensitivity of two species of bivalves viz. Paphia malabarica and Meretrix casta to gamma radiation. The comet assays was optimized and validated using different concentrations (18, 32 and 56 mg/L) of ethyl methanesulfonate (EMS), a direct-acting reference genotoxic agent, to which the bivalves were exposed for various times (24, 48 and 72 h). Bivalves were irradiated (single acute exposure) with 5 different doses (viz. 2, 4, 6, 8 and 10 Gy) of gamma radiation and their genotoxic effects on the haemocytes were studied using the comet assay. Haemolymph was collected from the adductor muscle at 24, 48 and 72 h of both EMS-exposed and irradiated bivalves and comet assay was carried out using standard protocol. A significant increase in DNA damage was observed as indicated by an increase in % tail DNA damage at different concentrations of EMS and all the doses of gamma radiation as compared to controls in

  18. Evaluation of γ-radiation-induced DNA damage in two species of bivalves and their relative sensitivity using comet assay

    International Nuclear Information System (INIS)

    Highlights: • Possible genotoxic effect of accidental exposure of aquatic fauna to γ radiation. • Relative sensitivity of bivalves to γ radiation is also analyzed using comet assay. • γ radiation induced significant genetic damage in both the species of bivalves. • P. malabarica and M. casta exhibited a similar level of sensitivity to γ radiation. • Comet assay may be used as a biomarker for the environmental biomonitoring. - Abstract: Ionizing radiation is known to induce genetic damage in diverse groups of organisms. Under accidental situations, large quantities of radioactive elements get released into the environment and radiation emitted from these radionuclides may adversely affect both the man and the non-human biota. The present study is aimed (a) to know the genotoxic effect of gamma radiation on aquatic fauna employing two species of selected bivalves, (b) to evaluate the possible use of ‘Comet assay’ for detecting genetic damage in haemocytes of bivalves as a biomarker for environmental biomonitoring and also (c) to compare the relative sensitivity of two species of bivalves viz. Paphia malabarica and Meretrix casta to gamma radiation. The comet assays was optimized and validated using different concentrations (18, 32 and 56 mg/L) of ethyl methanesulfonate (EMS), a direct-acting reference genotoxic agent, to which the bivalves were exposed for various times (24, 48 and 72 h). Bivalves were irradiated (single acute exposure) with 5 different doses (viz. 2, 4, 6, 8 and 10 Gy) of gamma radiation and their genotoxic effects on the haemocytes were studied using the comet assay. Haemolymph was collected from the adductor muscle at 24, 48 and 72 h of both EMS-exposed and irradiated bivalves and comet assay was carried out using standard protocol. A significant increase in DNA damage was observed as indicated by an increase in % tail DNA damage at different concentrations of EMS and all the doses of gamma radiation as compared to controls in

  19. Mutants of Ralstonia (Pseudomonas) solanacearum sensitive to antimicrobial peptides are altered in their lipopolysaccharide structure and are avirulent in tobacco

    OpenAIRE

    Titarenko, Elena; Lopez Solanilla, Emilia; García Olmedo, Francisco; Rodriguez Palenzuela, Pablo

    1997-01-01

    Ralstonia solanacearum K60 was mutagenized with the transposon Tn5, and two mutants, M2 and M88, were isolated. Both mutants were selected based on their increased sensitivity to thionins, and they had the Tn5 insertion in the same gene, 34 bp apart. Sequence analysis of the interrupted gene showed clear homology with the rfaF gene from Escherichia coli and Salmonella typhimurium (66% similarity), which encodes a heptosyltransferase involved in the synthesis of the lipopolysaccharide (LPS) co...

  20. Action video game playing is associated with improved visual sensitivity, but not alterations in visual sensory memory.

    Science.gov (United States)

    Appelbaum, L Gregory; Cain, Matthew S; Darling, Elise F; Mitroff, Stephen R

    2013-08-01

    Action video game playing has been experimentally linked to a number of perceptual and cognitive improvements. These benefits are captured through a wide range of psychometric tasks and have led to the proposition that action video game experience may promote the ability to extract statistical evidence from sensory stimuli. Such an advantage could arise from a number of possible mechanisms: improvements in visual sensitivity, enhancements in the capacity or duration for which information is retained in visual memory, or higher-level strategic use of information for decision making. The present study measured the capacity and time course of visual sensory memory using a partial report performance task as a means to distinguish between these three possible mechanisms. Sensitivity measures and parameter estimates that describe sensory memory capacity and the rate of memory decay were compared between individuals who reported high evels and low levels of action video game experience. Our results revealed a uniform increase in partial report accuracy at all stimulus-to-cue delays for action video game players but no difference in the rate or time course of the memory decay. The present findings suggest that action video game playing may be related to enhancements in the initial sensitivity to visual stimuli, but not to a greater retention of information in iconic memory buffers. PMID:23709062

  1. Locally Targeted Delivery of a Micron-Size Radiation Therapy Source Using Temperature-Sensitive Hydrogel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yusung, E-mail: yusung-kim@uiowa.edu [Department of Radiation Oncology, The University of Iowa, Iowa City, Iowa (United States); Seol, Dong Rim [Department of Orthopaedic Surgery, The University of Iowa, Iowa City, Iowa (United States); Mohapatra, Sucheta [Department of Biomedical Engineering, The University of Iowa, Iowa City, Iowa (United States); Sunderland, John J. [Department of Radiology, The University of Iowa, Iowa City, Iowa (United States); Schultz, Michael K. [Department of Radiation Oncology, The University of Iowa, Iowa City, Iowa (United States); Department of Radiology, The University of Iowa, Iowa City, Iowa (United States); Domann, Frederick E. [Department of Radiation Oncology, The University of Iowa, Iowa City, Iowa (United States); Department of Surgery, The University of Iowa, Iowa City, Iowa (United States); Lim, Tae-Hong [Department of Biomedical Engineering, The University of Iowa, Iowa City, Iowa (United States)

    2014-04-01

    Purpose: To propose a novel radiation therapy (RT) delivery modality: locally targeted delivery of micron-size RT sources by using temperature-sensitive hydrogel (RT-GEL) as an injectable vehicle. Methods and Materials: Hydrogel is a water-like liquid at room temperature but gels at body temperature. Two US Food and Drug Administration-approved polymers were synthesized. Indium-111 (In-111) was used as the radioactive RT-GEL source. The release characteristics of In-111 from polymerized RT-GEL were evaluated. The injectability and efficacy of RT-GEL delivery to human breast tumor were tested using animal models with control datasets of RT-saline injection. As proof-of-concept studies, a total of 6 nude mice were tested by injecting 4 million tumor cells into their upper backs after a week of acclimatization. Three mice were injected with RT-GEL and 3 with RT-saline. Single-photon emission computed tomography (SPECT) and CT scans were performed on each mouse at 0, 24, and 48 h after injection. The efficacy of RT-GEL was determined by comparison with that of the control datasets by measuring kidney In-111 accumulation (mean nCi/cc), representing the distant diffusion of In-111. Results: RT-GEL was successfully injected into the tumor by using a 30-gauge needle. No difficulties due to polymerization of hydrogel during injection and intratumoral pressure were observed during RT-GEL injection. No back flow occurred for either RT-GEL or RT-saline. The residual tumor activities of In-111 were 49% at 24 h (44% at 48 h, respectively) for RT-GEL and 29% (22%, respectively) for RT-saline. Fused SPECT-CT images of RT-saline showed considerable kidney accumulation of In-111 (2886%, 261%, and 262% of RT-GEL at 0, 24, and 48 h, respectively). Conclusions: RT-GEL was successfully injected and showed much higher residual tumor activity: 170% (200%, respectively), than that of RT-saline at 24 h (48 h, respectively) after injection with a minimal accumulation of In-111 to the

  2. Locally Targeted Delivery of a Micron-Size Radiation Therapy Source Using Temperature-Sensitive Hydrogel

    International Nuclear Information System (INIS)

    Purpose: To propose a novel radiation therapy (RT) delivery modality: locally targeted delivery of micron-size RT sources by using temperature-sensitive hydrogel (RT-GEL) as an injectable vehicle. Methods and Materials: Hydrogel is a water-like liquid at room temperature but gels at body temperature. Two US Food and Drug Administration-approved polymers were synthesized. Indium-111 (In-111) was used as the radioactive RT-GEL source. The release characteristics of In-111 from polymerized RT-GEL were evaluated. The injectability and efficacy of RT-GEL delivery to human breast tumor were tested using animal models with control datasets of RT-saline injection. As proof-of-concept studies, a total of 6 nude mice were tested by injecting 4 million tumor cells into their upper backs after a week of acclimatization. Three mice were injected with RT-GEL and 3 with RT-saline. Single-photon emission computed tomography (SPECT) and CT scans were performed on each mouse at 0, 24, and 48 h after injection. The efficacy of RT-GEL was determined by comparison with that of the control datasets by measuring kidney In-111 accumulation (mean nCi/cc), representing the distant diffusion of In-111. Results: RT-GEL was successfully injected into the tumor by using a 30-gauge needle. No difficulties due to polymerization of hydrogel during injection and intratumoral pressure were observed during RT-GEL injection. No back flow occurred for either RT-GEL or RT-saline. The residual tumor activities of In-111 were 49% at 24 h (44% at 48 h, respectively) for RT-GEL and 29% (22%, respectively) for RT-saline. Fused SPECT-CT images of RT-saline showed considerable kidney accumulation of In-111 (2886%, 261%, and 262% of RT-GEL at 0, 24, and 48 h, respectively). Conclusions: RT-GEL was successfully injected and showed much higher residual tumor activity: 170% (200%, respectively), than that of RT-saline at 24 h (48 h, respectively) after injection with a minimal accumulation of In-111 to the

  3. A Polymorphism Within the Promoter of the TGFβ1 Gene Is Associated With Radiation Sensitivity Using an Objective Radiologic Endpoint

    International Nuclear Information System (INIS)

    Purpose: To evaluate whether single nucleotide polymorphisms (SNPs) in the transforming growth factor-β1 (TGFβ1) gene are associated with radiation sensitivity using an objective radiologic endpoint. Methods and Materials: Preradiation therapy and serial postradiation therapy single photon emission computed tomography (SPECT) lung perfusion scans were obtained in patients undergoing treatment for lung cancer. Serial blood samples were obtained to measure circulating levels of TGFβ1. Changes in regional perfusion were related to regional radiation dose yielding a patient-specific dose–response curve, reflecting the patient’s inherent sensitivity to radiation therapy. Six TGFβ1 SNPs (-988, -800, -509, 869, 941, and 1655) were assessed using high-resolution melting assays and DNA sequencing. The association between genotype and slope of the dose–response curve, and genotype and TGFβ1 ratio (4-week/preradiation therapy), was analyzed using the Kruskal-Wallis test. Results: 39 white patients with preradiation therapy and ≥6-month postradiation therapy SPECT scans and blood samples were identified. Increasing slope of the dose–response curve was associated with the C(-509)T SNP (p = 0.035), but not the other analyzed SNPs. This SNP was also associated with higher TGFβ1 ratios. Conclusions: This study suggests that a polymorphism within the promoter of the TGFβ1 gene is associated with increased radiation sensitivity (defined objectively by dose-dependent changes in SPECT lung perfusion).

  4. In vivo sensitivity of the embryonic and adult neural stem cell compartments to low-dose radiation.

    Science.gov (United States)

    Barazzuol, Lara; Jeggo, Penny A

    2016-08-01

    The embryonic brain is radiation-sensitive, with cognitive deficits being observed after exposure to low radiation doses. Exposure of neonates to radiation can cause intracranial carcinogenesis. To gain insight into the basis underlying these outcomes, we examined the response of the embryonic, neonatal and adult brain to low-dose radiation, focusing on the neural stem cell compartments. This review summarizes our recent findings. At E13.5-14.5 the embryonic neocortex encompasses rapidly proliferating stem and progenitor cells. Exploiting mice with a hypomorphic mutation in DNA ligase IV (Lig4(Y288C) ), we found a high level of DNA double-strand breaks (DSBs) at E14.5, which we attribute to the rapid proliferation. We observed endogenous apoptosis in Lig4(Y288C) embryos and in WT embryos following exposure to low radiation doses. An examination of DSB levels and apoptosis in adult neural stem cell compartments, the subventricular zone (SVZ) and the subgranular zone (SGZ) revealed low DSB levels in Lig4(Y288C) mice, comparable with the levels in differentiated neuronal tissues. We conclude that the adult SVZ does not incur high levels of DNA breakage, but sensitively activates apoptosis; apoptosis was less sensitively activated in the SGZ, and differentiated neuronal tissues did not activate apoptosis. P5/P15 mice showed intermediate DSB levels, suggesting that DSBs generated in the embryo can be transmitted to neonates and undergo slow repair. Interestingly, this analysis revealed a stage of high endogenous apoptosis in the neonatal SVZ. Collectively, these studies reveal that the adult neural stem cell compartment, like the embryonic counterpart, can sensitively activate apoptosis. PMID:27125639

  5. Role of membrane Hsp70 in radiation sensitivity of tumor cells

    International Nuclear Information System (INIS)

    The major stress-inducible heat shock protein 70 (Hsp70) is frequently overexpressed in the cytosol and integrated in the plasma membrane of tumor cells via lipid anchorage. Following stress such as non-lethal irradiation Hsp70 synthesis is up-regulated. Intracellular located Hsp70 is known to exert cytoprotective properties, however, less is known about membrane (m)Hsp70. Herein, we investigate the role of mHsp70 in the sensitivity towards irradiation in tumor sublines that differ in their cytosolic and/or mHsp70 levels. The isogenic human colon carcinoma sublines CX+ with stable high and CX− with stable low expression of mHsp70 were generated by fluorescence activated cell sorting, the mouse mammary carcinoma sublines 4 T1 (4 T1 ctrl) and Hsp70 knock-down (4 T1 Hsp70 KD) were produced using the CRISPR/Cas9 system, and the Hsp70 down-regulation in human lung carcinoma sublines H1339 ctrl/H1339 HSF-1 KD and EPLC-272H ctrl/EPLC-272H HSF-1 KD was achieved by small interfering (si)RNA against Heat shock factor 1 (HSF-1). Cytosolic and mHsp70 was quantified by Western blot analysis/ELISA and flow cytometry; double strand breaks (DSBs) and apoptosis were measured by flow cytometry using antibodies against γH2AX and real-time PCR (RT-PCR) using primers and antibodies directed against apoptosis related genes; and radiation sensitivity was determined using clonogenic cell surviving assays. CX+/CX− tumor cells exhibited similar cytosolic but differed significantly in their mHsp70 levels, 4 T1 ctrl/4 T1 Hsp70 KD cells showed significant differences in their cytosolic and mHsp70 levels and H1339 ctrl/H1339 HSF-1 KD and EPLC-272H ctrl/EPLC-272H HSF-1 KD lung carcinoma cell sublines had similar mHsp70 but significantly different cytosolic Hsp70 levels. γH2AX was significantly up-regulated in irradiated CX− and 4 T1 Hsp70 KD with low basal mHsp70 levels, but not in their mHsp70 high expressing counterparts, irrespectively of their cytosolic Hsp70 content. After

  6. Deficient Expression of Aldehyde Dehydrogenase 1A1 Is Consistent with Increased Sensitivity of Gorlin Syndrome Patients to Radiation Carcinogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Aaron T.; Magnaldo, Thierry; Sontag, Ryan L.; Anderson, Lindsey N.; Sadler, Natalie C.; Piehowski, Paul D.; Gache, Yannick; Weber, Thomas J.

    2015-06-01

    Human phenotypes that are highly susceptible to radiation carcinogenesis have been identified. Sensitive phenotypes often display robust regulation of molecular features that modify biological response, which can facilitate identification of relevant pathways/networks. Here we interrogate primary dermal fibroblasts isolated from Gorlin syndrome patients (GDFs), who display a pronounced tumorigenic response to radiation, in comparison to normal human dermal fibroblasts (NHDFs). Our approach exploits newly developed thiol-reactive probes with a flexible click chemistry functional group to define changes in protein thiol profiles in live cell studies, which minimizes artifacts associated with cell lysis. We observe qualitative differences in protein thiol profiles by SDS-PAGE analysis when detection by iodoacetamide vs maleimide probe chemistries are compared, and pretreatment of cells with hydrogen peroxide eliminates detection of the majority of SDS-PAGE bands. Redox probes revealed deficient expression of an apparent 55 kDa protein thiol in GDFs from independent donors, compared with NHDFs. Proteomics tentatively identified this protein as aldehyde dehydrogenase 1A1 (ALDH1A1), a key enzyme regulating retinoic acid synthesis, and this deficiency was confirmed by Western blot. Redox probes revealed additional protein thiol differences between GDFs and NHDFs, including radiation responsive annexin family members. Our results indicate a multifactorial basis for the unusual sensitivity of Gorlin syndrome to radiation carcinogenesis, and the pathways identified have plausible implications for radiation health effects.

  7. Sensitivity of aerosol optical thickness and aerosol direct radiative effect to relative humidity

    Directory of Open Access Journals (Sweden)

    H. Bian

    2009-04-01

    Full Text Available We present a sensitivity study of the effects of spatial and temporal resolution of atmospheric relative humidity (RH on calculated aerosol optical thickness (AOT and the aerosol direct radiative effects (DRE in a global model. We carry out different modeling experiments using the same aerosol fields simulated in the Global Modeling Initiative (GMI model at a resolution of 2° latitude by 2.5° longitude, using time-averaged fields archived every three hours by the Goddard Earth Observation System Version 4 (GEOS-4, but we change the horizontal and temporal resolution of the relative humidity fields. We find that, on a global average, the AOT calculated using RH at a 1°×1.25° horizontal resolution is 11% higher than that using RH at a 2°×2.5° resolution, and the corresponding DRE at the top of the atmosphere is 8–9% and 15% more negative (i.e., more cooling for total aerosols and anthropogenic aerosol alone, respectively, in the finer spatial resolution case. The difference is largest over surface escarpment regions (e.g. >200% over the Andes Mountains where RH varies substantially with surface terrain. The largest zonal mean AOT difference occurs at 50–60° N (16–21%, where AOT is also relatively larger. A similar impact is also found when the time resolution of RH is increased. This increase of AOT and aerosol cooling with the increase of model resolution is due to the highly non-linear relationship between RH and the aerosol mass extinction efficiency (MEE at high RH (>80%. Our study is a specific example of the uncertainty in model results highlighted by multi-model comparisons such as AeroCom, and points out one of the many inter-model differences that can contribute to the overall spread among models.

  8. Partial inhibition of adipose tissue lipolysis improves glucose metabolism and insulin sensitivity without alteration of fat mass.

    Directory of Open Access Journals (Sweden)

    Amandine Girousse

    Full Text Available When energy is needed, white adipose tissue (WAT provides fatty acids (FAs for use in peripheral tissues via stimulation of fat cell lipolysis. FAs have been postulated to play a critical role in the development of obesity-induced insulin resistance, a major risk factor for diabetes and cardiovascular disease. However, whether and how chronic inhibition of fat mobilization from WAT modulates insulin sensitivity remains elusive. Hormone-sensitive lipase (HSL participates in the breakdown of WAT triacylglycerol into FAs. HSL haploinsufficiency and treatment with a HSL inhibitor resulted in improvement of insulin tolerance without impact on body weight, fat mass, and WAT inflammation in high-fat-diet-fed mice. In vivo palmitate turnover analysis revealed that blunted lipolytic capacity is associated with diminution in FA uptake and storage in peripheral tissues of obese HSL haploinsufficient mice. The reduction in FA turnover was accompanied by an improvement of glucose metabolism with a shift in respiratory quotient, increase of glucose uptake in WAT and skeletal muscle, and enhancement of de novo lipogenesis and insulin signalling in liver. In human adipocytes, HSL gene silencing led to improved insulin-stimulated glucose uptake, resulting in increased de novo lipogenesis and activation of cognate gene expression. In clinical studies, WAT lipolytic rate was positively and negatively correlated with indexes of insulin resistance and WAT de novo lipogenesis gene expression, respectively. In obese individuals, chronic inhibition of lipolysis resulted in induction of WAT de novo lipogenesis gene expression. Thus, reduction in WAT lipolysis reshapes FA fluxes without increase of fat mass and improves glucose metabolism through cell-autonomous induction of fat cell de novo lipogenesis, which contributes to improved insulin sensitivity.

  9. Partial inhibition of adipose tissue lipolysis improves glucose metabolism and insulin sensitivity without alteration of fat mass.

    Science.gov (United States)

    Girousse, Amandine; Tavernier, Geneviève; Valle, Carine; Moro, Cedric; Mejhert, Niklas; Dinel, Anne-Laure; Houssier, Marianne; Roussel, Balbine; Besse-Patin, Aurèle; Combes, Marion; Mir, Lucile; Monbrun, Laurent; Bézaire, Véronic; Prunet-Marcassus, Bénédicte; Waget, Aurélie; Vila, Isabelle; Caspar-Bauguil, Sylvie; Louche, Katie; Marques, Marie-Adeline; Mairal, Aline; Renoud, Marie-Laure; Galitzky, Jean; Holm, Cecilia; Mouisel, Etienne; Thalamas, Claire; Viguerie, Nathalie; Sulpice, Thierry; Burcelin, Rémy; Arner, Peter; Langin, Dominique

    2013-01-01

    When energy is needed, white adipose tissue (WAT) provides fatty acids (FAs) for use in peripheral tissues via stimulation of fat cell lipolysis. FAs have been postulated to play a critical role in the development of obesity-induced insulin resistance, a major risk factor for diabetes and cardiovascular disease. However, whether and how chronic inhibition of fat mobilization from WAT modulates insulin sensitivity remains elusive. Hormone-sensitive lipase (HSL) participates in the breakdown of WAT triacylglycerol into FAs. HSL haploinsufficiency and treatment with a HSL inhibitor resulted in improvement of insulin tolerance without impact on body weight, fat mass, and WAT inflammation in high-fat-diet-fed mice. In vivo palmitate turnover analysis revealed that blunted lipolytic capacity is associated with diminution in FA uptake and storage in peripheral tissues of obese HSL haploinsufficient mice. The reduction in FA turnover was accompanied by an improvement of glucose metabolism with a shift in respiratory quotient, increase of glucose uptake in WAT and skeletal muscle, and enhancement of de novo lipogenesis and insulin signalling in liver. In human adipocytes, HSL gene silencing led to improved insulin-stimulated glucose uptake, resulting in increased de novo lipogenesis and activation of cognate gene expression. In clinical studies, WAT lipolytic rate was positively and negatively correlated with indexes of insulin resistance and WAT de novo lipogenesis gene expression, respectively. In obese individuals, chronic inhibition of lipolysis resulted in induction of WAT de novo lipogenesis gene expression. Thus, reduction in WAT lipolysis reshapes FA fluxes without increase of fat mass and improves glucose metabolism through cell-autonomous induction of fat cell de novo lipogenesis, which contributes to improved insulin sensitivity. PMID:23431266

  10. Cinnamon improves insulin sensitivity and alters the body composition in an animal model of the metabolic syndrome.

    OpenAIRE

    Couturier, Karine; Batandier, Cécile; Awada, M.; Hininger-Favier, Isabelle; Canini, Frédéric; Anderson, Richard; Leverve, Xavier,; Roussel, Anne-Marie

    2010-01-01

    International audience Polyphenols from cinnamon (CN) have been described recently as insulin sensitizers and antioxidants but their effects on the glucose/insulin system in vivo have not been totally investigated. The aim of this study was to determine the effects of CN on insulin resistance and body composition, using an animal model of the metabolic syndrome, the high fat/high fructose (HF/HF) fed rat. Four groups of 22 male Wistar rats were fed for 12 weeks with: (i) (HF/HF) diet to in...

  11. Vinpocetine and Vitamin E Modulates Some Biochemical Alterations Induced by Exposure to Ionizing Radiation and Chloropyrifos in Rats

    International Nuclear Information System (INIS)

    Acapi-Cav is a well balanced and well tolerated formula containing vinpocetine and vitamin E. The objective of this study was to investigate the effect of vinpocetine and vitamin E on the oxidative stress, electrolytes and monoamines level in rats exposed to ionizing radiation (gamma rays), chloropyrifos (CPF) as well as rats exposed to a combination of gamma rays and CPF. Irradiation was performed by whole body exposure of rats to 8 Gy delivered at 1 Gy every 4 days. CPF was administered to rats by oral gavages at a dose of 3.6 mg/kg body weight ( 1/10 LD50 ) daily for 30 days. Vinpocetine and vitamin E were administered to rats by oral gavages at a dose of 20 mg/kg body weight daily during 7 days before starting the experiment and continued during the period of exposure to gamma rays and/or CPF. The results revealed significant increase of malondialdehyde (MDA) level associated with a significant decrease of glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) in the blood of rats exposed to gamma rays and/or CPF indicating oxidative stress. The levels of serum electrolytes (sodium Na+, potassium K+, calcium Ca++ and magnesium Mg) showed significant decrease. Serum dopamine (DA) level was decreased and norepinephrine (NE) was increased while epinephrine (EPI) showed non-significant change. The level of serum monoamine oxidase (MAO) showed significant increase. The administration of vinpocetine and vitamin E to rats exposed to gamma rays and/or CPF significantly reduced the amount of MDA which associated with an increase in the level of antioxidants and significant improvement was recorded for electrolytes level. The results demonstrated that vinpocetine and vitamin E significantly attenuated the increase of MAO and induced significant amelioration in the level of monoamines. It could be concluded that vinpocetine and vitamin E might protect the body from oxidative damage and electrolytes and monoamines alterations in rats exposed to gamma rays and

  12. Photosynthesis of two Arctic macroalgae under different ambient radiation levels and their sensitivity to enhanced UV radiation

    NARCIS (Netherlands)

    Brouwer, P.E.M.; Bischof, K.; Hanelt, D.; Kromkamp, J.C.

    2000-01-01

    The change in optimal quantum efficiency (F-v/F-m) of the Arctic species Laminaria saccharina and Palmaria palmata was investigated in a long-term experiment in situ under different radiation levels during the summer of 1997 in the Kongsfjord (Ny-Alesund, Spitsbergen, Norway, 78 degrees 55.5'N, 11 d

  13. Female Flinders Sensitive Line rats show estrous cycle-independent depression-like behavior and altered tryptophan metabolism

    DEFF Research Database (Denmark)

    Eskelund, Amanda; Budac, David P; Sanchez, Connie;

    2016-01-01

    female Flinders Sensitive Line (FSL) rats, a genetic rat model of depression. FSL rats and controls (Flinders Resistant Line rats), 12-20weeks old, were subject to the forced swim test (FST), a commonly used measure of depression-like behavior. Open field was used to evaluate locomotor ability and......Clinical studies suggest a link between depression and dysfunctional tryptophan (TRP) metabolism. Even though depression is twice as prevalent in women as men, the impact of the estrous cycle on TRP metabolism is not well-understood. Here we investigated 13 kynurenine and serotonin metabolites in...... male FSL and FRL rats. Female FSL rats showed a depression-like phenotype with increased immobility in the FST, not confounded by anxiety. In the brain, 3-hydroxykynurenine was increased whereas anthranilate and 5-hydroxytryptophan were decreased. In plasma, anthranilate and quinolinate levels were...

  14. Neuropeptide s alters anxiety but not depression-like behaviors in the flinders sensitive line rats, a genetic animal model

    DEFF Research Database (Denmark)

    Mathe, A.; Wegener, Gregers; Finger, B.;

    2010-01-01

    day FST. In selected animals effect of NPS on home cage activity was explored. Finally, brains from separate groups of naive animals were harvested; hippocampi, amygdalae and PVN punched out, and mRNA transcripts measured with the real-time quantitative polymerase chain reaction (rt-qPCR). Results...... the effects of centrally administered NPS on depression- and anxiety-related behaviors, using a well validated animal model of depression, the Flinders Sensitive Line (FSL) rats and their controls the Flinders Resistant Line (FRL). Methods: Male and female were tested. Seven days following insertion...... of cannula, 0.25 or 1.0 nmol NPS, or vehicle/5 ml were infused into the lateral ventricle. 45 min after NPS infusion animals were tested on elevated plus maze (EPM). Five days later the animals were subjected to the two-day forced swim test (FST); NPS or vehicle were injected 45 min before the second...

  15. Sensitivity of APSIM/ORYZA model due to estimation errors in solar radiation

    OpenAIRE

    Alexandre Bryan Heinemann; Pepijn A.J. van Oort; Diogo Simões Fernandes; Aline de Holanda Nunes Maia

    2012-01-01

    Crop models are ideally suited to quantify existing climatic risks. However, they require historic climate data as input. While daily temperature and rainfall data are often available, the lack of observed solar radiation (Rs) data severely limits site-specific crop modelling. The objective of this study was to estimate Rs based on air temperature solar radiation models and to quantify the propagation of errors in simulated radiation on several APSIM/ORYZA crop model seasonal outputs, yield, ...

  16. Effects of separate and combined treatments with gamma radiation and diethylnitrosamine in neonatal rats on the induction of altered hepatocyte foci and hepatic tumors

    International Nuclear Information System (INIS)

    To characterize the effects of combined treatments with gamma radiation and diethylnitrosamine (DEN) on the induction of histochemically detectable altered hepatocyte foci and hepatic tumors, we assessed the yields of these lesions in the livers of 150-day-old rats that had been treated neonatally with a single dose of gamma radiation and i.p.-injected DEN, either separately or in combination. The focus population was examined for two histochemical markers (elevated gamma glutamyl transpeptidase [GGT(+)] and iron exclusion [FE(-)] ), giving rise to three detectable focus phenotypes, i.e. GGT(+) foci, FE(-) foci, and GGT(+), FE(-) foci. These results suggest that (i) phenotypically distinguishable lesions, including foci with different histochemical marker patterns and tumors, originate from specific types of damage at different genetic loci and are developmentally independent; and (ii) the expression of the GGT(+) market per se in altered hepatocyte foci is not a reliable index of incipient hepatic neoplasia. (author)

  17. Can UV radiation affect benthic deposit-feeders through biochemical alteration of food resources? An experimental study with juveniles of the benthic polychaete Eupolymnia nebulosa.

    Science.gov (United States)

    Nahon, Sarah; Pruski, Audrey M; Duchêne, Jean-Claude; Méjanelle, Laurence; Vétion, Gilles; Desmalades, Martin; Charles, François

    2011-05-01

    The growth, tentacle development and feeding activity of the benthic polychaete Eupolymnia nebulosa were examined to determine whether UV might affect marine deposit-feeders indirectly through the modification of the nutritional quality of their resources. Since marine invertebrates have higher nutritional requirements during the period following settlement, we tested the effect of UV-altered phytodetritus on freshly settled juveniles of E. nebulosa. Phytodetritus was prepared from cultures of the diatom Skeletonema costatum either grown under or sheltered from UVB radiation. Sterol content of phytodetritus was unmodified by UV radiation. Conversely, phytodetritus was noticeably depleted in polyunsaturated fatty acids. Growth and tentacle development of juveniles fed on altered phytodetritus were reduced by 35% and 15% respectively, suggesting potential deficiencies in essential nutrients. In response to the lower quality of the phytodetritus, juveniles explored a wider area as they search for food, a strategy that could compensate for low food quality. PMID:21388674

  18. Sensitization to the behavioural effects of cocaine: alterations in tyrosine hydroxylase or endogenous opioid mRNAs are not necessarily involved.

    Science.gov (United States)

    Alvarez Fischer, D; Schäfer, M K; Ferger, B; Gross, S; Westermann, R; Weihe, E; Kuschinsky, K

    2001-03-01

    After repeated administration of cocaine at intervals, sensitization phenomena can be observed, so that its behavioural effects are enhanced. Since this phenomenon is long-lasting, it was of interest to study which persistent alterations in the activity of dopaminergic neurones or of endogenous opioid systems downstream of dopaminergic synapses in the basal ganglia are involved in the sensitization. Cocaine (10 mg/kg i.p.) was administered to rats on days 1, 3, 5 and 7 and saline on days 2, 4 and 6 ("repeated cocaine"), or saline was injected on days 1-6 and cocaine on day 7 ("acute cocaine"), or saline was injected on days 1-7 ("saline group"). The "repeated cocaine" schedule led to a significant sensitization to the locomotor activation produced by cocaine on day 7 or on day 17, 10 days after the end of sensitization protocol. Microdialysis in the nucleus accumbens which was performed after administration of cocaine (10 mg/kg i.p.) on day 7, or after an administration of the same dose 10 days after the last administration of cocaine, respectively, revealed significant acute increases of extracellular dopamine to about 200% of basal values. These increases were similar in "acute cocaine" and in "repeated cocaine" animals both after 7 days and after 17 days. For in situ hybridization studies, rats were sacrificed on day 7, 4.5 h after the last cocaine or saline administration. The mRNA for tyrosine hydroxylase (TH) in substantia nigra + ventral tegmental area was significantly elevated to about 140% of saline controls both in the "repeated cocaine" and the "acute cocaine" group as compared with the "saline group". In contrast, there were no differences between the three groups in the mRNAs of preprodynorphin or preproenkephalin levels measured in the nucleus accumbens (core and shell). These results suggest that sensitization phenomena to cocaine are not necessarily connected with alterations in the dopaminergic activity in the mesolimbic system or in the

  19. Differences in the radiation sensitivity of human tooth enamel in an individual and among the individuals in dental ESR dosimetry

    International Nuclear Information System (INIS)

    To study the individual difference of radiation sensitivity of tooth enamel in dental ESR dosimetry, 144 enamel samples were separated from 5 subjects, irradiated with 60Co gamma-rays up to 1290x10-4 C/kg (500 R), and measured with the ESR system. The coefficient of variation of ESR signals obtained for all enamel samples except two samples from one tooth was 7.8%. (author)

  20. JNK inhibition sensitizes tumor cells to radiation-induced premature senescence via Bcl-2/ROS/DDR signaling pathway

    International Nuclear Information System (INIS)

    Premature senescence is considered as a cellular defense mechanism to prevent tumorigenesis. Although recent evidences demonstrate that c-Jun N-terminal kinase (JNK) is involved in the senescence process, the target and exact mechanism of JNK signaling in the regulation of cell proliferation has yet to be defined. In this study, we investigated the role of JNK in premature senescence and demonstrated JNK inhibition sensitized tumor cells to radiation-induced premature senescence

  1. Characterization and application of radiation-sensitizing genes by DNA methylation in lung cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Il Lae; Kim, In Gyu; Kim, Kug Chan

    2011-03-15

    The sensitivity or resistance of cancer cells and normal tissues to ionizing radiation plays an important role in the clinical setting of lung cancer treatment. However, to date the exact molecular mechanisms of intrinsic radiosensitivity have not been well explained. In this study, we compared the radiosensitivity or radioresistance in two non-small cell lung cancers (NSCLCs), H460 and A549, and investigated the signaling pathways that confer radioresistance. H460 cells showed a significant G2/M arrest after 12 h of irradiation (5 Gy), reaching 60% of G2/M phase arrest. A549 cells also showed a significant G2/M arrest after 12 h of exposure; however, this arrest completely disappeared after 24 h of exposure. A549 has higher methylated CpG sites in PTEN, which is correlated with tumor radioresistance in some cancer cells, than H460 cells, and the average of the extent of the methylation was {approx}4.3 times higher in A549 cells than in H460 cells. As a result, PTEN expression was lower in A549 than in H460. Conducting Western blot analysis, we found that PTEN acted as a negative regulator for pAkt, and the pAkt acted as a negative regulator for p53 expression. According to the above results, we concluded that the radiosensitivity shown in H460 cells may be due to the higher expression of PTEN through p53 signaling pathway. The expression of the Wnt-antagonist Dickkopf gene (DKK) is downregulated in several types of tumors as a consequence of epigenetic DNA modification; four DKK members, DKK1, DKK2, DKK3, and DKK4, have been identified. In this study, we investigated another function of DKK3 in non-small cell lung cancer H460 cells, in which DKK3 was hypermethylated (44%) but still expressed, by interfering with DKK3 expression using DKK3-silencing RNA (SiRNA). We found that knockdown of DKK3 expression by DKK3 SiRNA transfection led to the detachment of H460 cells from the bottom of the culture plate and caused apoptosis. The expression of cyclindependent kinases

  2. Parameterization and sensitivity analyses of a radiative transfer model for remote sensing plant canopies

    Science.gov (United States)

    Hall, Carlton Raden

    A major objective of remote sensing is determination of biochemical and biophysical characteristics of plant canopies utilizing high spectral resolution sensors. Canopy reflectance signatures are dependent on absorption and scattering processes of the leaf, canopy properties, and the ground beneath the canopy. This research investigates, through field and laboratory data collection, and computer model parameterization and simulations, the relationships between leaf optical properties, canopy biophysical features, and the nadir viewed above-canopy reflectance signature. Emphasis is placed on parameterization and application of an existing irradiance radiative transfer model developed for aquatic systems. Data and model analyses provide knowledge on the relative importance of leaves and canopy biophysical features in estimating the diffuse absorption a(lambda,m-1), diffuse backscatter b(lambda,m-1), beam attenuation alpha(lambda,m-1), and beam to diffuse conversion c(lambda,m-1 ) coefficients of the two-flow irradiance model. Data sets include field and laboratory measurements from three plant species, live oak (Quercus virginiana), Brazilian pepper (Schinus terebinthifolius) and grapefruit (Citrus paradisi) sampled on Cape Canaveral Air Force Station and Kennedy Space Center Florida in March and April of 1997. Features measured were depth h (m), projected foliage coverage PFC, leaf area index LAI, and zenith leaf angle. Optical measurements, collected with a Spectron SE 590 high sensitivity narrow bandwidth spectrograph, included above canopy reflectance, internal canopy transmittance and reflectance and bottom reflectance. Leaf samples were returned to laboratory where optical and physical and chemical measurements of leaf thickness, leaf area, leaf moisture and pigment content were made. A new term, the leaf volume correction index LVCI was developed and demonstrated in support of model coefficient parameterization. The LVCI is based on angle adjusted leaf

  3. Ionising radiation induces persistent alterations in the cardiac mitochondrial function of C57BL/6 mice 40 weeks after local heart exposure

    International Nuclear Information System (INIS)

    Background and purpose: Radiotherapy of thoracic and chest-wall tumours increases the long-term risk of radiation-induced heart disease. The aim of this study was to investigate the long-term effect of local heart irradiation on cardiac mitochondria. Methods: C57BL/6 and atherosclerosis-prone ApoE−/− mice received local heart irradiation with a single X-ray dose of 2 Gy. To investigate the low-dose effect, C57BL/6 mice also received a single heart dose of 0.2 Gy. Functional and proteomic alterations of cardiac mitochondria were evaluated after 40 weeks, compared to age-matched controls. Results: The respiratory capacity of irradiated C57BL/6 cardiac mitochondria was significantly reduced at 40 weeks. In parallel, protein carbonylation was increased, suggesting enhanced oxidative stress. Considerable alterations were found in the levels of proteins of mitochondria-associated cytoskeleton, respiratory chain, ion transport and lipid metabolism. Radiation induced similar but less pronounced effects in the mitochondrial proteome of ApoE−/− mice. In ApoE−/−, no significant change was observed in mitochondrial respiration or protein carbonylation. The dose of 0.2 Gy had no significant effects on cardiac mitochondria. Conclusion: This study suggests that ionising radiation causes non-transient alterations in cardiac mitochondria, resulting in oxidative stress that may ultimately lead to malfunctioning of the heart muscle

  4. Real and limit sensitivity of some radiation detectors of THz/sub-THz ranges

    Directory of Open Access Journals (Sweden)

    Shevchik-Shekera A. V.

    2012-02-01

    Full Text Available It is shown that while calculating the NEP parameter of radiation detectors of THz/sub-THz range, the fluctuations of the background radiation flux at different temperatures of the background in the case of diffraction-limited beam should be taken into account.

  5. Metabolic alterations and drug sensitivity of tyrosine kinase inhibitor resistant leukemia cells with a FLT3/ITD mutation.