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Sample records for low-dose hypersensitive keratinocyte

  1. Single Low-Dose Radiation Induced Regulation of Keratinocyte Differentiation in Calcium-Induced HaCaT Cells

    Science.gov (United States)

    Hahn, Hyung Jin; Youn, Hae Jeong; Cha, Hwa Jun; Kim, Karam; An, Sungkwan

    2016-01-01

    Background We are continually exposed to low-dose radiation (LDR) in the range 0.1 Gy from natural sources, medical devices, nuclear energy plants, and other industrial sources of ionizing radiation. There are three models for the biological mechanism of LDR: the linear no-threshold model, the hormetic model, and the threshold model. Objective We used keratinocytes as a model system to investigate the molecular genetic effects of LDR on epidermal cell differentiation. Methods To identify keratinocyte differentiation, we performed western blots using a specific antibody for involucrin, which is a precursor protein of the keratinocyte cornified envelope and a marker for keratinocyte terminal differentiation. We also performed quantitative polymerase chain reaction. We examined whether LDR induces changes in involucrin messenger RNA (mRNA) and protein levels in calcium-induced keratinocyte differentiation. Results Exposure of HaCaT cells to LDR (0.1 Gy) induced p21 expression. p21 is a key regulator that induces growth arrest and represses stemness, which accelerates keratinocyte differentiation. We correlated involucrin expression with keratinocyte differentiation, and examined the effects of LDR on involucrin levels and keratinocyte development. LDR significantly increased involucrin mRNA and protein levels during calcium-induced keratinocyte differentiation. Conclusion These studies provide new evidence for the biological role of LDR, and identify the potential to utilize LDR to regulate or induce keratinocyte differentiation. PMID:27489424

  2. Implications of effects ''adaptive response'', ''low-dose hypersensitivity'' und ''bystander effect'' for cancer risk at low doses and low dose rates

    International Nuclear Information System (INIS)

    Jacob, P

    2006-01-01

    A model for carcinogenesis (the TSCE model) was applied in order to examine the effects of ''Low-dose hypersensitivity (LDH)'' and the ''Bystander effect (BE)'' on the derivation of radiation related cancer mortality risks. LDH has been discovered to occur in the inactivation of cells after acute exposure to low LET radiation. A corresponding version of the TSCE model was applied to the mortality data on the Abomb survivors from Hiroshima and Nagasaki. The BE has been mainly observed in cells after exposure to high LET radiation. A Version of the TSCE model which included the BE was applied to the data on lung cancer mortality from the workers at the Mayak nuclear facilities who were exposed to Plutonium. In general an equally good description of the A-bomb survivor mortality data (for all solid, stomach and lung tumours) was found for the TSCE model and the (conventional) empirical models but fewer parameters were necessary for the TSCE model. The TSCE model which included the effects of radiation induced cell killing resulted in non-linear dose response curves with excess relative risks after exposure at young ages that were generally lower than in the models without cell killing. The main results from TSCE models which included cell killing described by either conventional survival curves or LDH were very similar. A sub multiplicative effect from the interaction of smoking and exposure to plutonium was found to result from the analysis of the Mayak lung cancer mortality data. All models examined resulted in the predominant number of Mayak lung cancer deaths being ascribed to smoking. The interaction between smoking and plutonium exposures was found to be the second largest effect. The TSCE model resulted in lower estimates for the lung cancer excess relative risk per unit plutonium dose than the empirical risk model, but this difference was not found to be statistically significant. The excess relative risk dose responses were linear in the empirical model and

  3. Single Low-Dose Radiation Induced Regulation of Keratinocyte Differentiation in Calcium-Induced HaCaT Cells

    OpenAIRE

    Hahn, Hyung Jin; Youn, Hae Jeong; Cha, Hwa Jun; Kim, Karam; An, Sungkwan; Ahn, Kyu Joong

    2016-01-01

    Background We are continually exposed to low-dose radiation (LDR) in the range 0.1 Gy from natural sources, medical devices, nuclear energy plants, and other industrial sources of ionizing radiation. There are three models for the biological mechanism of LDR: the linear no-threshold model, the hormetic model, and the threshold model. Objective We used keratinocytes as a model system to investigate the molecular genetic effects of LDR on epidermal cell differentiation. Methods To identify kera...

  4. Immediate hypersensitivity to iodinated contrast media: diagnostic accuracy of skin tests and intravenous provocation test with low dose.

    Science.gov (United States)

    Sesé, L; Gaouar, H; Autegarden, J-E; Alari, A; Amsler, E; Vial-Dupuy, A; Pecquet, C; Francès, C; Soria, A

    2016-03-01

    The diagnosis of HSR to iodinated contrast media (ICM) is challenging based on clinical history and skin tests. This study evaluates the negative predictive value (NPV) of skin tests and intravenous provocation test (IPT) with low-dose ICM in patients with suspected immediate hypersensitivity reaction (HSR) to ICM. Thirty-seven patients with suspected immediate hypersensitivity reaction to ICM were included retrospectively. Skin tests and a single-blind placebo-controlled intravenous provocation test (IPT) with low-dose iodinated contrast media (ICM) were performed. Skin tests with ICM were positive in five cases (one skin prick test and five intradermal test). Thirty-six patients were challenged successfully by IPT, and only one patient had a positive challenge result, with a grade I reaction by the Ring and Messmer classification. Ten of 23 patients followed up by telephone were re-exposed to a negative tested ICM during radiologic examination; two experienced a grade I immediate reaction. For immediate hypersensitivity reaction to ICM, the NPV for skin tests and IPT with low dose was 80% (95% CI 44-97%). © 2016 John Wiley & Sons Ltd.

  5. GATA3 is a master regulator of the transcriptional response to low-dose ionizing radiation in human keratinocytes

    Energy Technology Data Exchange (ETDEWEB)

    Bonin, F.; Molina, M.; Berthier-Vergnes, O.; Lamartine, J. [Universite de Lyon, Lyon, F-69003 (France); Universite Lyon 1, Lyon, F-69003 (France); CNRS, UMR5534, Centre de Genetique Moleculaire et Cellulaire, Villeurbanne, F-69622 (France); Malet, C.; Ginestet, C. [Centre Leon Berard, Service de Radiotherapie, Lyon F-69008 (France); Martin, M.T. [Laboratoire de Genomique et Radiobiologie de la Keratinopoiese, CEA, IRCM, Evry F-91000 (France)

    2009-07-01

    Background: The general population is constantly exposed to low levels of radiation through natural, occupational or medical irradiation. Even if the biological effects of low-level radiation have been intensely debated and investigated, the molecular mechanisms underlying the cellular response to low doses remain largely unknown. Results: The present study investigated the role of GATA3 protein in the control of the cellular and molecular response of human keratinocytes exposed to a 1 cGy dose of X-rays. Chromatin immunoprecipitation showed GATA3 to be able to bind the promoter of 4 genes responding to a 1 cGy exposure. To go further into the role of GATA3 after ionizing radiation exposure, we studied the cellular and molecular consequences of radiation in GATA3 knock-down cells. Knockdown was obtained by lentiviral-mediated expression of an shRNA targeting the GATA3 transcript in differentiated keratinocytes. First, radiosensitivity was assessed: the toxicity, in terms of immediate survival (with XTT test), associated with 1 cGy radiation was found to be increased in GATA3 knock-down cells. The impact of GATA3 knock-down on the transcriptome of X-ray irradiated cells was also investigated, using oligonucleotide micro-arrays to assess changes between 3 h and 72 h post-irradiation in normal vs GATA3 knock-down backgrounds; transcriptome response was found to be completely altered in GATA3 knock-down cells, with a strong induction/repression peak 48 h after irradiation. Functional annotation revealed enrichment in genes known to be involved in chaperone activity, TGF{beta} signalling and stress response. Conclusion: Taken together, these data indicate that GATA3 is an important regulator of the cellular and molecular response of epidermal cells to very low doses of radiation. (authors)

  6. GATA3 is a master regulator of the transcriptional response to low-dose ionizing radiation in human keratinocytes

    International Nuclear Information System (INIS)

    Bonin, F.; Molina, M.; Berthier-Vergnes, O.; Lamartine, J.; Malet, C.; Ginestet, C.; Martin, M.T.

    2009-01-01

    Background: The general population is constantly exposed to low levels of radiation through natural, occupational or medical irradiation. Even if the biological effects of low-level radiation have been intensely debated and investigated, the molecular mechanisms underlying the cellular response to low doses remain largely unknown. Results: The present study investigated the role of GATA3 protein in the control of the cellular and molecular response of human keratinocytes exposed to a 1 cGy dose of X-rays. Chromatin immunoprecipitation showed GATA3 to be able to bind the promoter of 4 genes responding to a 1 cGy exposure. To go further into the role of GATA3 after ionizing radiation exposure, we studied the cellular and molecular consequences of radiation in GATA3 knock-down cells. Knockdown was obtained by lentiviral-mediated expression of an shRNA targeting the GATA3 transcript in differentiated keratinocytes. First, radiosensitivity was assessed: the toxicity, in terms of immediate survival (with XTT test), associated with 1 cGy radiation was found to be increased in GATA3 knock-down cells. The impact of GATA3 knock-down on the transcriptome of X-ray irradiated cells was also investigated, using oligonucleotide micro-arrays to assess changes between 3 h and 72 h post-irradiation in normal vs GATA3 knock-down backgrounds; transcriptome response was found to be completely altered in GATA3 knock-down cells, with a strong induction/repression peak 48 h after irradiation. Functional annotation revealed enrichment in genes known to be involved in chaperone activity, TGFβ signalling and stress response. Conclusion: Taken together, these data indicate that GATA3 is an important regulator of the cellular and molecular response of epidermal cells to very low doses of radiation. (authors)

  7. Cytogenetic Effects of Low Dose Radiation in Mammalian Cells Analysis of the Phenomenon Hypersensitivity and Induced Radioresistence

    CERN Document Server

    Shmakova, N L; Nasonova, E A; Krasavin, E A; Rsjanina, A V

    2001-01-01

    The induction of cytogenetic damage after irradiation of chinese hamster cells and human melanoma cells within dose range 1-200 cGy was studied. The anaphase and metaphase analysis of chromosome damage and micronuclei test were applied. The hypersensitivity (HRS) at doses below 20 cGy and the increased radioresistence at higher doses (IR) were shown with all cytogenetic criteria for both cell lines. The phenomenon of HRS/IR was reproduced in synchronic as well as in asynchronic population of chinese hamster cells. This fact shows that HRS was caused by high radiosensitivity of all cells and can not be explained by any differential sensitivity of cells in different phases of the cell cycle. So it was supposed that the increasing radioresistence is determined by the inclusion of the inducible repair processes in all cells. This conclusion agress with the fact that there was no evidence of HRS on dose-effect curves and that some part of pre-existent damage was repaired after preliminary irradiation with low dose...

  8. Low-dose dose-response for reduced cell viability after exposure of human keratinocyte (HEK001 cells to arsenite

    Directory of Open Access Journals (Sweden)

    Kenneth T. Bogen

    Full Text Available The in vitro arsenite (AsIII cytotoxicity dose-response (DR of human keratinocytes (HEK001 was examined at greater statistical resolution than ever previously reported using the MTT assay to determine cell viability. Fifty-four 96-well plates were treated with AsIII concentrations of 0.25, 0.5, 1, 2, 3, 4, 5, 7, 10, 15, 20, 25, or 30 μM. Because of unexpected variation in viability response patterns, a two-stage DR analysis was used in which data on plate-specific viability (%, estimated as 100% times the ratio of measured viability in exposed to unexposed cells, were fit initially to a generalized lognormal response function positing that HEK001 cells studied consisted of: a proportion P of relatively highly sensitive (HS cells, a proportion Po of relatively resistant cells, and a remaining (1–P–Po fraction of typical-sensitivity (TS cells exhibiting the intermediate level of AsIII sensitivity characteristic of most cells in each assay. The estimated fractions P and Po were used to adjust data from all 54 plates (and from the 28 plates yielding the best fits to reflect the condition that P = Po = 0 to provide detailed DR analysis specifically for TS cells. Four DR models fit to the combined adjusted data were each very predictive (R2 > 0.97 overall but were inconsistent with at least one of the data set examined (p  0.30 and exceeded 100% significance (p ≤ 10−6. A low-dose hormetic model provided the best fit to the combined adjusted data for TS cells (R2 = 0.995. Marked variability in estimates of P (the proportion of apparent HS cells was unexpected, not readily explained, and warrants further study using additional cell lines and assay methods, and in vivo. Keywords: Arsenic, Arsenate, Cell culture, Cell death, Cytotoxicity, HEK001 cells

  9. Chronic low-dose UVA irradiation induces local suppression of contact hypersensitivity, Langerhans cell depletion and suppressor cell activation in C3H/HeJ mice

    International Nuclear Information System (INIS)

    Bestak, Rosa; Halliday, G.M.

    1996-01-01

    It has previously been demonstrated that chronic low-dose solar-simulated UV radiation could induce both local and systemic immunosuppression as well as tolerance to a topically applied hapten. In this study, we have used a chronic low-dose UV-irradiation protocol to investigate the effects of UVA on the skin immune system of C3H/HeJ mice. Irradiation with UVA+B significantly suppressed the local and systemic primary contact hypersensitivity (CHS) response to the hapten 2,4,6-trinitrochlorobenzene. Furthermore, UVA+B reduced Langerhans cell (LC) and dendritic epidermal T cell (DETC) densities in chronically UV-irradiated mice. Ultraviolet A irradiation induced local, but not systemic, immunosuppression and reduced LC (32%) but not DETC from the epidermis compared to the shaved control animals. Treatment of mice with both UVA+B and UVA radiation also induced an impaired secondary CHS response, and this tolerance was transferable with spleen cells. (Author)

  10. The effect of chronic low-dose UVB radiation on Langerhans cells, sunburn cells, urocanic acid isomers, contact hypersensitivity and serum immunoglobulins in mice

    International Nuclear Information System (INIS)

    El-Ghorr, A.A.; Norval, M.; Lappin, M.B.

    1995-01-01

    C3H mice were irradiated three times a week for up to 6 weeks with either 500 J/m 2 or 1000 J/m 2 broadband UVB (270-350 nm) or 3000 J/m 2 narrowband UVB (311-312 nm; TL01 source). Each dose was suberythemal to the mouse strain used. The number of Langerhans cells (LC) in the epidermis was reduced by over 50% after 2 weeks of irradiation with the UVB source and by 20% following TL01 irradiation. Continued irradiation for up to 6 weeks resulted in no further decrease in LC numbers in the case of the UVB source but a steady decline to 40% in the case of the TL01 source. Sunburn cells were detected following irradiation with both sources but the numbers were very low in comparison with acute exposure. Ultraviolet-B exposure resulted in doubling of the thickness of the epidermis throughout the 6 weeks of irradiation while TL01 exposure did not alter epidermal thickness. Conversion of trans- to cis-urocanic acid (UCA) was observed with both UVB and TL01 sources. The percentage of cis-UCA started to return to normal after 4 weeks of TL01 exposure despite continued irradiation. As observed following a single exposure, the contact hypersensitivity (CH) response was significantly reduced following 6 weeks of UVB irradiation but was unaffected by TL01 exposure, indicating no correlation between cis-UCA levels and CH response. (author)

  11. The elimination of low-dose hypersensitivity in Chinese hamster V79-379A cells by pretreatment with X rays or hydrogen peroxide

    International Nuclear Information System (INIS)

    Marples, B.; Joiner, M.C.

    1995-01-01

    To explain increased radioresistance over the X-ray dose range ∼ 0.5-1 Gy an inducible radioprotective mechanism triggered by DNA damage was proposed; hypersensitivity to doses much-lt Gy reflected the response prior to the activation of this system. To test this hypothesis, cells were pre-exposed to DNA-damaging agents in an attempt to induce the process prematurely. An increase in survival was evident at X-ray doses below 0.3 Gy after a priming treatment of X rays (0.05, 0.2, 1 Gy) given 6 h earlier. The protective effect was found to be transitory, requiring time for development and diminishing after two to three cell cycle times. Cycloheximide administered in the interval between the priming and challenge doses of X rays abolished the protection conferred by pretreatment, indicating the involvement of de novo protein synthesis. Oxidative damage by nontoxic doses of hydrogen peroxide (10 -4 M, but not 10 -6 M) also produced a protective effect against subsequent X irradiation. These experiments indicate survival in the hyper-radiosensitive region (much-lt 0.5 Gy) can be modified by pretreatment with agents known to affect DNA repair. In addition, the development of increased radioresistance after single doses of X rays was inhibited by cycloheximide treatment. These studies provide evidence to support the explanations proposed previously for the phenomena of increased radioresistance and hyper-radiosensitivity observed at very low X-ray doses. 57 refs., 6 figs., 3 tabs

  12. LDR brachytherapy: can low dose rate hypersensitivity from the "inverse" dose rate effect cause excessive cell killing to peripherial connective tissues and organs?

    Science.gov (United States)

    Leonard, B E; Lucas, A C

    2009-02-01

    Examined here are the possible effects of the "inverse" dose rate effect (IDRE) on low dose rate (LDR) brachytherapy. The hyper-radiosensitivity and induced radioresistance (HRS/IRR) effect benefits cell killing in radiotherapy, and IDRE and HRS/IRR seem to be generated from the same radioprotective mechanisms. We have computed the IDRE excess cell killing experienced in LDR brachytherapy using permanent seed implants. We conclude, firstly, that IDRE is a dose rate-dependent manifestation of HRS/IRR. Secondly, the presence of HRS/IRR or IDRE in a cell species or tissue must be determined by direct dose-response measurements. Thirdly, a reasonable estimate is that 50-80% of human adjoining connective and organ tissues experience IDRE from permanent implanted LDR brachytherapy. If IDRE occurs for tissues at point A for cervical cancer, the excess cell killing will be about a factor of 3.5-4.0 if the initial dose rate is 50-70 cGy h(-1). It is greater for adjacent tissues at lower dose rates and higher for lower initial dose rates at point A. Finally, higher post-treatment complications are observed in LDR brachytherapy, often for unknown reasons. Some of these are probably a result of IDRE excess cell killing. Measurements of IDRE need be performed for connective and adjacent organ tissues, i.e. bladder, rectum, urinary tract and small bowels. The measured dose rate-dependent dose responses should extended to tissues and organs remain above IDRE thresholds).

  13. Effect of treatment with cyclophosphamide in low doses upon the onset of delayed type hypersensitivity in mice chronically infected with Trypanosoma cruzi: involvement of heart interstitial dendritic cells

    Directory of Open Access Journals (Sweden)

    Torriceli Souza The

    2013-09-01

    Full Text Available Acute infection with Trypanosoma cruzi results in intense myocarditis, which progresses to a chronic, asymptomatic indeterminate form. The evolution toward this chronic cardiac form occurs in approximately 30% of all cases of T. cruzi infection. Suppression of delayed type hypersensitivity (DTH has been proposed as a potential explanation of the indeterminate form. We investigated the effect of cyclophosphamide (CYCL treatment on the regulatory mechanism of DTH and the participation of heart interstitial dendritic cells (IDCs in this process using BALB/c mice chronically infected with T. cruzi. One group was treated with CYCL (20 mg/kg body weight for one month. A DTH skin test was performed by intradermal injection of T. cruzi antigen (3 mg/mL in the hind-footpad and measured the skin thickness after 24 h, 48 h and 72 h. The skin test revealed increased thickness in antigen-injected footpads, which was more evident in the mice treated with CYCL than in those mice that did not receive treatment. The thickened regions were characterised by perivascular infiltrates and areas of necrosis. Intense lesions of the myocardium were present in three/16 cases and included large areas of necrosis. Morphometric evaluation of lymphocytes showed a predominance of TCD8 cells. Heart IDCs were immunolabelled with specific antibodies (CD11b and CD11c and T. cruzi antigens were detected using a specific anti-T. cruzi antibody. Identification of T. cruzi antigens, sequestered in these cells using specific anti-T. cruzi antibodies was done, showing a significant increase in the number of these cells in treated mice. These results indicate that IDCs participate in the regulatory mechanisms of DTH response to T. cruzi infection.

  14. Double strand break induction and kinetics indicate preserved hypersensitivity in keratinocytes to subtherapeutic doses for 7weeks of radiotherapy.

    Science.gov (United States)

    Qvarnström, Fredrik; Simonsson, Martin; Nyman, Jan; Hermansson, Ingegerd; Book, Majlis; Johansson, Karl-Axel; Turesson, Ingela

    2017-01-01

    Previously we reported that hyper-radiosensitivity (HRS) was evidenced by quantifying DNA double strand break (DSB) foci in epidermis biopsies collected after delivering radiotherapeutic one and five dose fractions. The aim of this study was to determine whether HRS was preserved throughout a 7-week radiotherapy treatment, and also to examine the rate of foci decline and foci persistence between dose fractions. 42 patients with prostate cancer received 7-week fractionated radiotherapy treatment (RT) with daily dose fractions of 0.05-1.10Gy to the skin. Before RT, and at several times throughout treatment, skin biopsies (n=452) were collected at 30min, and 2, 3, 24, and 72h after dose fractions. DSB-foci markers, γH2AX and 53BP1, were labelled in epidermal keratinocytes with immunofluorescence and immunohistochemical staining. Foci were counted both with digital image analysis and manually. HRS in keratinocytes was evidenced by the dose-response relationships of DSB foci, observed throughout the treatment course, independent of sampling time and quantification method. Foci observed at 24h after dose fractions indicated considerable DSB persistence. Accordingly, foci significantly accumulated after 5 consecutive dose fractions. For doses below 0.3Gy, persistent foci could be observed even at 72h after damage induction. A comparison of γH2AX and 53BP1 quantifications in double-stained biopsies showed similar HRS dose-response relationships. These results represented the first evidence of preserved HRS, assessed by γH2AX- and 53BP1-labelled DSB foci, throughout a 7-week treatment course with daily repeated subtherapeutic dose fractions. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  15. Low doses effects

    International Nuclear Information System (INIS)

    Tubiana, M.

    1997-01-01

    In this article is asked the question about a possible carcinogens effect of low dose irradiation. With epidemiological data, knowledge about the carcinogenesis, the professor Tubiana explains that in spite of experiments made on thousand or hundred of thousands animals it has not been possible to bring to the fore a carcinogens effect for low doses and then it is not reasonable to believe and let the population believe that low dose irradiation could lead to an increase of neoplasms and from this point of view any hardening of radiation protection standards could in fact, increase anguish about ionizing radiations. (N.C.)

  16. Low dose epidemiologic studies

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    In this chapter the BEIR committee has reviewed low-dose irradiation studies since the BEIR III report. They have considered the carcinogenic effectiveness of low-LET in populations exposed to radiation from a number of different sources: diagnostic radiography; fallout from nuclear weapons testing; nuclear installations; radiation in the workplace and high levels of natural background radiation

  17. Effects of low doses

    International Nuclear Information System (INIS)

    Le Guen, B.

    2001-01-01

    Actually, even though it is comfortable for the risk management, the hypothesis of the dose-effect relationship linearity is not confirmed for any model. In particular, in the area of low dose rate delivered by low let emitters. this hypothesis is debated at the light of recent observations, notably these ones relative to the mechanisms leading to genetic instability and induction eventuality of DNA repair. The problem of strong let emitters is still to solve. (N.C.)

  18. Low Dose Ionizing Radiation Modulates Immune Function

    International Nuclear Information System (INIS)

    Nelson, Gregory A.

    2016-01-01

    In order to examine the effects of low dose ionizing radiation on the immune system we chose to examine an amplified adaptive cellular immunity response. This response is Type IV delayed-type hypersensitivity also called contact hypersensitivity. The agent fluorescein isothiocyanate (FITC) is a low molecular weight, lipophilic, reactive, fluorescent molecule that can be applied to the skin where it (hapten) reacts with proteins (carriers) to become a complete antigen. Exposure to FITC leads to sensitization which is easily measured as a hypersensitivity inflammatory reaction following a subsequent exposure to the ear. Ear swelling, eosinophil infiltration, immunoglobulin E production and cytokine secretion patterns characteristic of a 'Th2 polarized' immune response are the components of the reaction. The reaction requires successful implementation of antigen processing and presentation by antigen presenting Langerhans cells, communication with naïve T lymphocytes in draining lymph nodes, expansion of activated T cell clones, migration of activated T cells to the circulation, and recruitment of memory T cells, macrophages and eosinophils to the site of the secondary challenge. Using this model our approach was to quantify system function rather than relying only on indirect biomarkers of cell. We measured the FITC-induced hypersensitivity reaction over a range of doses from 2 cGy to 2 Gy. Irradiations were performed during key events or prior to key events to deplete critical cell populations. In addition to quantifying the final inflammatory response, we assessed cell populations in peripheral blood and spleen, cytokine signatures, IgE levels and expression of genes associated with key processes in sensitization and elicitation/recall. We hypothesized that ionizing radiation would produce a biphasic effect on immune system function resulting in an enhancement at low doses and a depression at higher doses and suggested that this transition would occur in

  19. Low Dose Ionizing Radiation Modulates Immune Function

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Gregory A. [Loma Linda Univ., CA (United States)

    2016-01-12

    In order to examine the effects of low dose ionizing radiation on the immune system we chose to examine an amplified adaptive cellular immunity response. This response is Type IV delayed-type hypersensitivity also called contact hypersensitivity. The agent fluorescein isothiocyanate (FITC) is a low molecular weight, lipophilic, reactive, fluorescent molecule that can be applied to the skin where it (hapten) reacts with proteins (carriers) to become a complete antigen. Exposure to FITC leads to sensitization which is easily measured as a hypersensitivity inflammatory reaction following a subsequent exposure to the ear. Ear swelling, eosinophil infiltration, immunoglobulin E production and cytokine secretion patterns characteristic of a “Th2 polarized” immune response are the components of the reaction. The reaction requires successful implementation of antigen processing and presentation by antigen presenting Langerhans cells, communication with naïve T lymphocytes in draining lymph nodes, expansion of activated T cell clones, migration of activated T cells to the circulation, and recruitment of memory T cells, macrophages and eosinophils to the site of the secondary challenge. Using this model our approach was to quantify system function rather than relying only on indirect biomarkers of cell. We measured the FITC-induced hypersensitivity reaction over a range of doses from 2 cGy to 2 Gy. Irradiations were performed during key events or prior to key events to deplete critical cell populations. In addition to quantifying the final inflammatory response, we assessed cell populations in peripheral blood and spleen, cytokine signatures, IgE levels and expression of genes associated with key processes in sensitization and elicitation/recall. We hypothesized that ionizing radiation would produce a biphasic effect on immune system function resulting in an enhancement at low doses and a depression at higher doses and suggested that this transition would occur in the

  20. Low doses effects and gamma radiations low dose rates

    International Nuclear Information System (INIS)

    Averbeck, D.

    1999-01-01

    This expose wishes for bringing some definitions and base facts relative to the problematics of low doses effects and low dose rates effects. It shows some already used methods and some actual experimental approaches by focusing on the effects of ionizing radiations with a low linear energy transfer. (N.C.)

  1. Copper hypersensitivity

    DEFF Research Database (Denmark)

    Fage, Simon W; Faurschou, Annesofie; Thyssen, Jacob P

    2014-01-01

    hypersensitivity, a database search of PubMed was performed with the following terms: copper, dermatitis, allergic contact dermatitis, contact hypersensitivity, contact sensitization, contact allergy, patch test, dental, IUD, epidemiology, clinical, and experimental. Human exposure to copper is relatively common...

  2. Health effect of low dose/low dose rate radiation

    International Nuclear Information System (INIS)

    Kodama, Seiji

    2012-01-01

    The clarified and non-clarified scientific knowledge is discussed to consider the cause of confusion of explanation of the title subject. The low dose is defined roughly lower than 200 mGy and low dose rate, 0.05 mGy/min. The health effect is evaluated from 2 aspects of clinical symptom/radiation hazard protection. In the clinical aspect, the effect is classified in physical (early and late) and genetic ones, and is classified in stochastic (no threshold value, TV) and deterministic (with TV) ones from the radioprotection aspect. Although the absence of TV in the carcinogenic and genetic effects has not been proved, ICRP employs the stochastic standpoint from the safety aspect for radioprotection. The lowest human TV known now is 100 mGy, meaning that human deterministic effect would not be generated below this dose. Genetic deterministic effect can be observable only in animal experiments. These facts suggest that the practical risk of exposure to <100 mGy in human is the carcinogenesis. The relationship between carcinogenic risk in A-bomb survivors and their exposed dose are found fitted to the linear no TV model, but the epidemiologic data, because of restriction of subject number analyzed, do not always mean that the model is applicable even below the dose <100 mGy. This would be one of confusing causes in explanation: no carcinogenic risk at <100 mGy or risk linear to dose even at <100 mGy, neither of which is scientifically conclusive at present. Also mentioned is the scarce risk of cancer in residents living in the high background radiation regions in the world in comparison with that in the A-bomb survivors exposed to the chronic or acute low dose/dose rate. Molecular events are explained for the low-dose radiation-induced DNA damage and its repair, gene mutation and chromosome aberration, hypothesis of carcinogenesis by mutation, and non-targeting effect of radiation (bystander effect and gene instability). Further researches to elucidate the low dose

  3. Statistical and low dose response

    International Nuclear Information System (INIS)

    Thorson, M.R.; Endres, G.W.R.

    1981-01-01

    The low dose response and the lower limit of detection of the Hanford dosimeter depend upon may factors, including the energy of the radiation, whether the exposure is to be a single radiation or mixed fields, annealing cycles, environmental factors, and how well various batches of TLD materials are matched in the system. A careful statistical study and sensitivity analysis were performed to determine how these factors influence the response of the dosimeter system. Estimates have been included in this study of the standard deviation of calculated dose for various mixed field exposures from 0 to 1000 mrem

  4. Hypersensitivity vasculitis

    Science.gov (United States)

    Cutaneous small vessel vasculitis; Allergic vasculitis; Leukocytoclastic vasculitis ... Hypersensitivity vasculitis, or cutaneous small vessel vasculitis, is caused by: An allergic reaction to a drug or other foreign ...

  5. Low Dose Risk, Decisions, and Risk Communication

    International Nuclear Information System (INIS)

    Flynn, James

    2002-01-01

    The overall research objective was to establish new levels of information about how people, groups, and communities respond to low dose radiation exposure. This is basic research into the social psychology of individual, group, and community responses to radiation exposures. The results of this research are directed to improving risk communication and public participation in management of environmental problems resulting from low dose radiation

  6. Hypersensitivity reaction with intravenous GnRH after pulsatile subcutaneous GnRH treatment in male hypogonadotrophic hypogonadism.

    OpenAIRE

    Popović, V.; Milosević, Z.; Djukanović, R.; Micić, D.; Nesović, M.; Manojlović, D.; Djordjević, P.; Mićić, J.

    1988-01-01

    Chronic pulsatile subcutaneous administration of low doses of gonadotrophin releasing hormone (GnRH) is an effective therapy for men with hypogonadotrophic hypogonadism. Hypersensitivity reactions to GnRH are rare. We wish to report hypersensitivity reactions with intravenous GnRH after low dose subcutaneous pulsatile GnRH treatment in two men with hypogonadotrophic hypogonadism due to suprasellar disease.

  7. Low dose irradiation and biological defense mechanisms

    International Nuclear Information System (INIS)

    Sugahara, Tsutomu; Sagan, L.A.; Aoyama, Takashi

    1992-01-01

    It has been generally accepted in the context of radiation protection that ionizing radiation has some adverse effect even at low doses. However, epidemiological studies of human populations cannot definitively show its existence or absence. Furthermore, recent studies of populations living in areas of different background radiation levels reported some decrease in adverse health effects at high background levels. Genetic studies of atomic bomb survivors failed to produce statistically significant findings on the mutagenic effects of ionizing radiation. A British study however, suggests that a father's exposure to low dose radiation on the job may increase his children's risk of leukemia. On the other hand, many experimental studies have raised the possibility that low doses of ionizing radiation may not be harmful or may even produce stimulating or adaptive responses. The term 'hormesis' has come to be used to describe these phenomena produced by low doses of ionizing radiation when they were beneficial for the organisms studied. At the end of the International Conference on Low Dose Irradiation one conclusion appeared to be justified: radiation produces an adaptive response, though it is not universally detected yet. The conference failed to obtain any consensus on risk assessment at low doses, but raised many problems to be dealt with by future studies. The editors therefore believe that the Proceedings will be useful for all scientists and people concerned with radiation protection and the biological effects of low-dose irradiation

  8. Hypersensitive tourists

    DEFF Research Database (Denmark)

    Jensen, Martin Trandberg

    2016-01-01

    This research note sets forth a new agendum for sensuous tourism scholarship. It departs in the neglected study of the embodied life of hypersensitive tourists, and argues that the ambiguousness of the sensuous be better understood. To contextualise this argument the following suggests that aller......This research note sets forth a new agendum for sensuous tourism scholarship. It departs in the neglected study of the embodied life of hypersensitive tourists, and argues that the ambiguousness of the sensuous be better understood. To contextualise this argument the following suggests...... that allergic tourists make up a contemporary and increasingly relevant empirical field through which to illuminate the dark sides of the sensuous. Finally, the note develops four analytical dimensions that structure critical sensuous scholarship....

  9. Metronidazole hypersensitivity.

    Science.gov (United States)

    Knowles, S; Choudhury, T; Shear, N H

    1994-03-01

    To report a case of a possible hypersensitivity reaction induced by metronidazole. An Asian woman with a history of recurrent vaginitis had previously developed localized erythema while on intravaginal metronidazole and nystatin. While receiving oral metronidazole for treatment of a current bacterial vaginosis, she developed chills, fever, generalized erythema, and a rash within 60 minutes of the first dose. Treatment with diphenhydramine was instituted. The following day while in the hospital, the patient's condition worsened; she experienced shortness of breath and increased edema of the extremities. Methylprednisolone was administered with diphenhydramine and her condition improved over the next 5 days. The patient's vaginitis was treated with gentian violet and she was discharged on a tapering dosage of prednisone. Metronidazole-induced cutaneous reactions and systemic hypersensitivity reactions are reviewed. Alternatives to metronidazole and other potential cross-reactive drugs are suggested for the treatment of recurrent vaginitis. Although the patient's initial reaction to metronidazole represented a rare event, written documentation and communication in the patient's native language may have prevented the subsequent severe hypersensitivity reaction.

  10. Reduced oxygen enhancement ratio at low doses

    International Nuclear Information System (INIS)

    Palcic, B.; Skarsgard, L.D.

    1984-01-01

    The oxygen depletion rate in cell suspensions was measured using a Clark electrode. It was found that under experimental conditions used in this laboratory for hypoxic irradiations, the oxygen levels before the start of irradiation are always below 0.1μm, the levels which could give any significant enhancement to radiation inactivation by x-rays. The measured O/sub 2/ depletion rates were comparable to those reported in the literature. Chinese hamster cells (CHO) were made hypoxic by gas exchange, combined with metabolic consumption of oxygen by cells at 37 0 C. Full survival curves were determined in the dose range 0 to 3Gy using the low dose survival assay. The results confirmed the authors' earlier finding that the OER decreases at low doses. The authors therefore believe that the dose-dependent OER is a true radiobiological phenomenon and not an artifact of the experimental method used in the low dose survival assay

  11. LOW DOSE RISK, DECISIONS, and RISK COMMUNICATION

    International Nuclear Information System (INIS)

    Flynn, James

    2002-01-01

    The objective of this project is to conduct basic research on how people receive, evaluate, and form positions on scientific information and its relationship to low-dose radiation exposure. There are three major areas of study in our research program. First is the development of theories, frameworks and concepts essential to guiding data collection and analysis. The second area is a program of experimental studies on risk perception, evaluation of science information, and the structure of individual positions regarding low-dose exposures. Third is the community-level studies to examine and record how the social conditions, under which science communications take place, influence the development of attitudes and opinions about: low-dose exposures, the available management options, control of radiation risks, and preferences for program and policy goals

  12. Responses of epithelial cells to low and very low doses of low let radiation

    International Nuclear Information System (INIS)

    Mothersill, Carmel; Seymour, Colin

    2003-01-01

    Recent advances in our knowledge of the biological effects of low doses of ionizing radiation have shown unexpected phenomena. These vary in the endpoint used to detect them and in the dose range examined but all occur as high-frequency events in cell populations. They include: 1. a 'bystander effect' which can be demonstrated at low doses as a transferable.factor(s) causing radiobiological effects in unexposed cells, 2. an assortment of delayed effects' occurring in progeny of cells exposed to low doses, 3. Low-dose Hypersensitivity (HRS) and Increased radioresistance (IRR) which can collectively be demonstrated as a change in the dose-effect relationship, occurring around 0.5-1 Gy of low LET radiation and 4. adaptive responses where cells exposed to very low doses followed by higher doses, exhibit an induced relatively resistant response to the second dose. In all cases, the effect of very low doses is greater than would be predicted by extrapolation of high dose data and is inconsistent with conventional DNA break/repair-based radiobiology. In practical risk assessment terms, the relative importance of the effects are high at low doses where they dominate the response, and small at high doses. This paper reviews these assorted phenomena and in particular seeks to explore whether related or distinct mechanisms underlie these various effects Understanding the mechanistic basis of these phenomena may suggest new approaches to controlling death or survival sectoring at low radiation doses. The key question is whether these low dose phenomena necessitate a new approach to risk assessment. (author)

  13. Exposure to low doses of ionizing radiations

    International Nuclear Information System (INIS)

    Le Guen, B.

    2008-01-01

    The author discusses the knowledge about the effects of ionizing radiations on mankind. Some of them have been well documented (skin cancer and leukaemia for the pioneer scientists who worked on radiations, some other types of cancer for workers who handled luminescent paints, rock miners, nuclear explosion survivors, patients submitted to radiological treatments). He also evokes the issue of hereditary cancers, and discusses the issue of low dose irradiation where some surveys can now be performed on workers. He discusses the biological effects of these low doses. He outlines that many questions remain about these effects, notably the influence of dose level and of dose rate level on the biological reaction

  14. Biological influence from low dose and low-dose rate radiation

    International Nuclear Information System (INIS)

    Magae, Junji

    2007-01-01

    Although living organisms have defense mechanisms for radioadaptive response, the influence is considered to vary qualitatively and quantitatively for low dose and high dose, as well as for low-dose rate and high-dose rate. This article describes the bioresponse to low dose and low-dose rate. Among various biomolecules, DNA is the most sensitive to radiation, and accurate replication of DNA is an essential requirement for the survival of living organisms. Also, the influence of active enzymes resulted from the effect of radiation on enzymes in the body is larger than the direct influence of radiation on the body. After this, the article describes the carcinogenic risk by low-dose radiation, and then so-called Hormesis effect to create cancer inhibition effect by stimulating active physiology. (S.K.)

  15. Carcinogenesis induced by low-dose radiation

    Directory of Open Access Journals (Sweden)

    Piotrowski Igor

    2017-11-01

    Full Text Available Although the effects of high dose radiation on human cells and tissues are relatively well defined, there is no consensus regarding the effects of low and very low radiation doses on the organism. Ionizing radiation has been shown to induce gene mutations and chromosome aberrations which are known to be involved in the process of carcinogenesis. The induction of secondary cancers is a challenging long-term side effect in oncologic patients treated with radiation. Medical sources of radiation like intensity modulated radiotherapy used in cancer treatment and computed tomography used in diagnostics, deliver very low doses of radiation to large volumes of healthy tissue, which might contribute to increased cancer rates in long surviving patients and in the general population. Research shows that because of the phenomena characteristic for low dose radiation the risk of cancer induction from exposure of healthy tissues to low dose radiation can be greater than the risk calculated from linear no-threshold model. Epidemiological data collected from radiation workers and atomic bomb survivors confirms that exposure to low dose radiation can contribute to increased cancer risk and also that the risk might correlate with the age at exposure.

  16. Stimulation of seeds by low dose irradiation

    International Nuclear Information System (INIS)

    Lawson, Helen

    1976-05-01

    The first section of the bibliography lists materials on the stimulation of seeds by low dose irradiation, with particular reference to stimulation of germination and yield. The second section contains a small number of selected references on seed irradiation facilities. (author)

  17. RAC1 in keratinocytes regulates crosstalk to immune cells by Arp2/3-dependent control of STAT1

    DEFF Research Database (Denmark)

    Pedersen, Esben Ditlev Kølle; Wang, Zhipeng; Stanley, Alanna

    2012-01-01

    Crosstalk between keratinocytes and immune cells is crucial for the immunological barrier function of the skin, and aberrant crosstalk contributes to inflammatory skin diseases. Using mice with a keratinocyte-restricted deletion of the RAC1 gene we found that RAC1 in keratinocytes plays...... hypersensitive to inflammatory stimuli both in vitro and in vivo, suggesting a major role for RAC1 in regulating the crosstalk between the epidermis and the immune system....

  18. Low dose irradiation reduces cancer mortality rates

    International Nuclear Information System (INIS)

    Luckey, T.D.

    2000-01-01

    Low doses of ionizing radiation stimulate development, growth, memory, sensual acuity, fecundity, and immunity (Luckey, T.D., ''Radiation Hormesis'', CRC Press, 1991). Increased immune competence reduces cancer mortality rates and provides increased average lifespan in animals. Decreased cancer mortality rates in atom bomb victims who received low dose irradiation makes it desirable to examine populations exposed to low dose irradiation. Studies with over 300,000 workers and 7 million person-years provide a valid comparison of radiation exposed and control unclear workers (Luckey, T.D., Nurture with Ionizing Radiation, Nutrition and Cancer, 34:1-11, 1999). Careful selection of controls eliminated any ''healthy worker effect''. The person-year corrected average indicated the cancer mortality rate of exposed workers was only 51% that of control workers. Lung cancer mortality rates showed a highly significant negative correlation with radon concentrations in 272,000 U.S. homes (Cohen, B.L., Health Physics 68:157-174, 1995). In contrast, radon concentrations showed no effect on lung cancer rates in miners from different countries (Lubin, J.H. Am. J. Epidemiology 140:323-332, 1994). This provides evidence that excessive lung cancer in miners is caused by particulates (the major factor) or toxic gases. The relative risk for cancer mortality was 3.7% in 10,000 Taiwanese exposed to low level of radiation from 60 Co in their steel supported homes (Luan, Y.C. et al., Am. Nuclear Soc. Trans. Boston, 1999). This remarkable finding needs further study. A major mechanism for reduced cancer mortality rates is increased immune competence; this includes both cell and humoral components. Low dose irradiation increases circulating lymphocytes. Macrophage and ''natural killer'' cells can destroy altered (cancer) cells before the mass becomes too large. Low dose irradiation also kills suppressor T-cells; this allows helper T-cells to activate killer cells and antibody producing cells

  19. Mammography-oncogenecity at low doses

    International Nuclear Information System (INIS)

    Heyes, G J; Mill, A J; Charles, M W

    2009-01-01

    Controversy exists regarding the biological effectiveness of low energy x-rays used for mammography breast screening. Recent radiobiology studies have provided compelling evidence that these low energy x-rays may be 4.42 ± 2.02 times more effective in causing mutational damage than higher energy x-rays. These data include a study involving in vitro irradiation of a human cell line using a mammography x-ray source and a high energy source which matches the spectrum of radiation observed in survivors from the Hiroshima atomic bomb. Current radiation risk estimates rely heavily on data from the atomic bomb survivors, and a direct comparison between the diagnostic energies used in the UK breast screening programme and those used for risk estimates can now be made. Evidence highlighting the increase in relative biological effectiveness (RBE) of mammography x-rays to a range of x-ray energies implies that the risks of radiation-induced breast cancers for mammography x-rays are potentially underestimated by a factor of four. A pooled analysis of three measurements gives a maximal RBE (for malignant transformation of human cells in vitro) of 4.02 ± 0.72 for 29 kVp (peak accelerating voltage) x-rays compared to high energy electrons and higher energy x-rays. For the majority of women in the UK NHS breast screening programme, it is shown that the benefit safely exceeds the risk of possible cancer induction even when this higher biological effectiveness factor is applied. The risk/benefit analysis, however, implies the need for caution for women screened under the age of 50, and particularly for those with a family history (and therefore a likely genetic susceptibility) of breast cancer. In vitro radiobiological data are generally acquired at high doses, and there are different extrapolation mechanisms to the low doses seen clinically. Recent low dose in vitro data have indicated a potential suppressive effect at very low dose rates and doses. Whilst mammography is a low

  20. New risk estimates at low doses

    International Nuclear Information System (INIS)

    Fry, R.J.M.

    1992-01-01

    The age of molecular radiation epidemiology may be at hand. The techniques are available to establish with the degree of precision required to determine whether agent-specific mutations can be identified consistently. A concerted effort to examine radiation-induced changes in as many relevant genes as possible appears to be justified. Cancers in those exposed to low doses of ionizing radiation should be chosen for the investigation. Parallel studies of radiation-induced cancers in experimental animals would not only complement the human studies, but perhaps reveal approaches to extrapolation of risk estimates across species. A caveat should be added to this optimistic view of what molecular studies might contribute to the knotty problem of risk estimates at low doses. The suggestions are made by one with no expertise in the field of molecular biology

  1. Cytogenetic effects of low-dose radiation

    International Nuclear Information System (INIS)

    Metalli, P.

    1983-01-01

    The effects of ionizing radiation on chromosomes have been known for several decades and dose-effect relationships are also fairly well established in the mid- and high-dose and dose-rate range for chromosomes of mammalian cells. In the range of low doses and dose rates of different types of radiation few data are available for direct analysis of the dose-effect relationships, and extrapolation from high to low doses is still the unavoidable approach in many cases of interest for risk assessment. A review is presented of the data actually available and of the attempts that have been made to obtain possible generalizations. Attention is focused on some specific chromosomal anomalies experimentally induced by radiation (such as reciprocal translocations and aneuploidies in germinal cells) and on their relevance for the human situation. (author)

  2. Epigenomic Adaptation to Low Dose Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Gould, Michael N. [Univ. of Wisconsin, Madison, WI (United States)

    2015-06-30

    The overall hypothesis of this grant application is that the adaptive responses elicited by low dose ionizing radiation (LDIR) result in part from heritable DNA methylation changes in the epigenome. In the final budget period at the University of Wisconsin-Madison, we will specifically address this hypothesis by determining if the epigenetically labile, differentially methylated regions (DMRs) that regulate parental-specific expression of imprinted genes are deregulated in agouti mice by low dose radiation exposure during gestation. This information is particularly important to ascertain given the 1) increased human exposure to medical sources of radiation; 2) increased number of people predicted to live and work in space; and 3) enhanced citizen concern about radiation exposure from nuclear power plant accidents and terrorist ‘dirty bombs.’

  3. Radiation effects of high and low doses

    International Nuclear Information System (INIS)

    El-Naggar, A.M.

    1998-01-01

    The extensive proliferation of the uses and applications of atomic and nuclear energy resulted in possible repercussions on human health. The prominent features of the health hazards that may be incurred after exposure to high and low radiation doses are discussed. The physical and biological factors involved in the sequential development of radiation health effects and the different cellular responses to radiation injury are considered. The main criteria and features of radiation effects of high and low doses are comprehensively outlined

  4. Estimation of radiation risks at low dose

    International Nuclear Information System (INIS)

    1990-04-01

    The report presents a review of the effects caused by radiation in low doses, or at low dose rates. For the inheritable (or ''genetic''), as well as for the cancer producing effects of radiation, present evidence is consistent with: (a) a non-linear relationship between the frequency of at least some forms of these effects, with comparing frequencies caused by doses many times those received annually from natural sources, with those caused by lower doses; (b) a probably linear relationship, however, between dose and frequency of effects for dose rates in the region of that received from natural sources, or at several times this rate; (c) no evidence to indicate the existence of a threshold dose below which such effects are not produced, and a strong inference from the mode of action of radiation on cells at low dose rates that no such thresholds are likely to apply to the detrimental, cancer-producing or inheritable, effects resulting from unrepaired damage to single cells. 19 refs

  5. Deep learning for low-dose CT

    Science.gov (United States)

    Chen, Hu; Zhang, Yi; Zhou, Jiliu; Wang, Ge

    2017-09-01

    Given the potential risk of X-ray radiation to the patient, low-dose CT has attracted a considerable interest in the medical imaging field. Currently, the main stream low-dose CT methods include vendor-specific sinogram domain filtration and iterative reconstruction algorithms, but they need to access raw data whose formats are not transparent to most users. Due to the difficulty of modeling the statistical characteristics in the image domain, the existing methods for directly processing reconstructed images cannot eliminate image noise very well while keeping structural details. Inspired by the idea of deep learning, here we combine the autoencoder, deconvolution network, and shortcut connections into the residual encoder-decoder convolutional neural network (RED-CNN) for low-dose CT imaging. After patch-based training, the proposed RED-CNN achieves a competitive performance relative to the-state-of-art methods. Especially, our method has been favorably evaluated in terms of noise suppression and structural preservation.

  6. Low doses of gamma radiation in soybean

    International Nuclear Information System (INIS)

    Franco, José G.; Franco, Suely S.H.; Villavicencio, Anna L.C.; Arthur, Valter; Arthur, Paula B.; Franco, Caio H.

    2017-01-01

    The degree of radiosensitivity depends mostly on the species, the stage of the embryo at irradiation, the doses employed and the criteria used to measure the effect. One of the most common criteria to evaluate radiosensitivity in seeds is to measure the average plant production. Dry soya seeds were exposed to low doses of gamma radiation from source of Cobalt-60, type Gammecell-220, at 0.210 kGy dose rate. In order to study stimulation effects of radiation on germination, plant growth and production. A treatment with four radiation doses was applied as follows: 0 (control); 12.5; 25.0 and 50.0 Gy. Seed germination and harvested of number of seeds and total production were assessed to identify occurrence of stimulation. Soya seeds number and plants were handled as for usual seed production in Brazil. The low doses of gamma radiation in the seeds that stimulate the production were the doses of 12.5 and 50.0 Gy. The results show that the use of low doses of gamma radiation can stimulate germination and plant production. (author)

  7. Modification of damage following low doses

    International Nuclear Information System (INIS)

    Braby, L.A.; Nelson, J.M.; Metting, N.F.

    1988-01-01

    At very low doses the damage-interaction mechanism is responsible for very little lethal or potentially lethal damage, and repair of the latter should essentially disappear. An alternative model suggests that potentially lethal damage is either repaired with a constant half time or misrepaired at a rate which is proportional to the square of the damage concentration. In this case, as the dose decreases, the probability of misrepair decreases faster than the probability of repair, and repair becomes a more pronounced feature of the cell response. Since the consequence of unrepaired damage is an important question in determining the effects of low doses of radiation delivered at low dose rates, we have attempted to determine which of these two types of models is consistent with the response of plateau-phase CHO cells. In the earlier experiments, there was no indication of repair after a 50-rad exposure with a 24-hour split dose or plating delay; in fact, immediate plating resulted in survival slightly above control and delayed plating in survival slightly below the control value

  8. Low doses of gamma radiation in soybean

    Energy Technology Data Exchange (ETDEWEB)

    Franco, José G.; Franco, Suely S.H.; Villavicencio, Anna L.C., E-mail: zegilmar60@gmail.com, E-mail: gilmita@uol.com.br, E-mail: villavic@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil); Arthur, Valter; Arthur, Paula B., E-mail: arthur@cena.usp.br [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil); Franco, Caio H. [Universidade Federal de São Paulo (UNIFESP), SP (Brazil). Departamento de Microbiologia, Imunologia e Parasitologia

    2017-07-01

    The degree of radiosensitivity depends mostly on the species, the stage of the embryo at irradiation, the doses employed and the criteria used to measure the effect. One of the most common criteria to evaluate radiosensitivity in seeds is to measure the average plant production. Dry soya seeds were exposed to low doses of gamma radiation from source of Cobalt-60, type Gammecell-220, at 0.210 kGy dose rate. In order to study stimulation effects of radiation on germination, plant growth and production. A treatment with four radiation doses was applied as follows: 0 (control); 12.5; 25.0 and 50.0 Gy. Seed germination and harvested of number of seeds and total production were assessed to identify occurrence of stimulation. Soya seeds number and plants were handled as for usual seed production in Brazil. The low doses of gamma radiation in the seeds that stimulate the production were the doses of 12.5 and 50.0 Gy. The results show that the use of low doses of gamma radiation can stimulate germination and plant production. (author)

  9. Biological effects of low doses of radiation at low dose rate

    International Nuclear Information System (INIS)

    1996-05-01

    The purpose of this report was to examine available scientific data and models relevant to the hypothesis that induction of genetic changes and cancers by low doses of ionizing radiation at low dose rate is a stochastic process with no threshold or apparent threshold. Assessment of the effects of higher doses of radiation is based on a wealth of data from both humans and other organisms. 234 refs., 26 figs., 14 tabs

  10. Estimation of low-dose radiation-responsive proteins in the absence of genomic instability in normal human fibroblast cells.

    Science.gov (United States)

    Yim, Ji-Hye; Yun, Jung Mi; Kim, Ji Young; Nam, Seon Young; Kim, Cha Soon

    2017-11-01

    Low-dose radiation has various biological effects such as adaptive responses, low-dose hypersensitivity, as well as beneficial effects. However, little is known about the particular proteins involved in these effects. Here, we sought to identify low-dose radiation-responsive phosphoproteins in normal fibroblast cells. We assessed genomic instability and proliferation of fibroblast cells after γ-irradiation by γ-H2AX foci and micronucleus formation analyses and BrdU incorporation assay, respectively. We screened fibroblast cells 8 h after low-dose (0.05 Gy) γ-irradiation using Phospho Explorer Antibody Microarray and validated two differentially expressed phosphoproteins using Western blotting. Cell proliferation proceeded normally in the absence of genomic instability after low-dose γ-irradiation. Phospho antibody microarray analysis and Western blotting revealed increased expression of two phosphoproteins, phospho-NFκB (Ser536) and phospho-P70S6K (Ser418), 8 h after low-dose radiation. Our findings suggest that low-dose radiation of normal fibroblast cells activates the expression of phospho-NFκB (Ser536) and phospho-P70S6K (Ser418) in the absence of genomic instability. Therefore, these proteins may be involved in DNA damage repair processes.

  11. Bioavailability of diclofenac potassium at low doses

    Science.gov (United States)

    Hinz, Burkhard; Chevts, Julia; Renner, Bertold; Wuttke, Henrike; Rau, Thomas; Schmidt, Andreas; Szelenyi, Istvan; Brune, Kay; Werner, Ulrike

    2005-01-01

    Aim Diclofenac-K has been recently launched at low oral doses in different countries for over-the-counter use. However, given the considerable first-pass metabolism of diclofenac, the degree of absorption of diclofenac-K at low doses remained to be determined. The aim of this study was to determine the bioavailability of low-dose diclofenac-K. Methods A randomized, three-way, cross-over study was performed in 10 subjects. Each received diclofenac-K, 22.5 mg via short-term i.v. infusion and orally at single doses of 12.5 mg and 25 mg. Results Mean (± SD) times to maximal plasma concentration (tmax) of diclofenac were 0.48 ± 0.28 h (12.5 mg) and 0.93 ± 0.96 h (25 mg). The absolute bioavailability of diclofenac-K after oral administration did not differ significantly in the 12.5-mg and 25-mg dose group (63.1 ± 12.6% vs. 65.1 ± 19.4%, respectively). The 90% confidence intervals for the AUC∞ and AUCt ratios for the two oral regimes were 82.6, 103.4% (point estimate 92.4%) and 86.2, 112.9% (point estimate 98.6%), respectively. These values were within the acceptance criteria for bioequivalence (80–125%). Conclusions Our data indicate that diclofenac-K is rapidly and well absorbed at low dose, and are consistent with a rapid onset of action of the drug. Abbreviations AUC, area under plasma concentraton-time curve; Cmax, peak plasma concentration; CI, confidence interval; COX, cyclooxygenase; D, dose; F, absolute bioavailability; tmax, time to reach Cmax. PMID:15606444

  12. Effects of low doses of ionizing radiation

    International Nuclear Information System (INIS)

    Anon.

    2008-01-01

    Ionizing radiation of cosmic or terrestrial origin is part of the environment in which all living things have evolved since the creation of the universe. The artificial radioactivity generated by medical diagnostic and treatment techniques, some industrial activities, radioactive fallout, etc. has now been added to this natural radioactivity. This article reviews the biological effects of the low doses of ionizing radiation to which the population is thus exposed. Their carcinogenic risk cannot simply be extrapolated from what we know about high-dose exposure. (author)

  13. Low dose radiation and diabetes mellitus

    International Nuclear Information System (INIS)

    Zhao Hongguang; Gong Shouliang; Cai Lu

    2006-01-01

    Induction of hormesis and adaptive response by low-dose radiatio (LDR) has been extensively indicated. It's mechanism may be related with the protective protein and antioxidants that LDR induced, which take effects on the diabetes mellitus (DM) and other diseases. This review will summarize available dat with emphasis on three points: the preventive effect of LDR on the development of diabetes, the therapeutic effect of LDR on diabetic complications and possible mechanisms by which LDR prevents the development of diabetes and diabetic complications. Finally, the perspectives of LDR clinical, diabetes-related implication are discussed. (authors)

  14. Low-dose effect on blood chromosomes

    International Nuclear Information System (INIS)

    Pohl-Rueling, J.

    1992-01-01

    Linear dose response relationships of biological effects at low doses are experimentally and theoretically disputed. Structural chromosome aberration rates at doses ranging from normal background exposures up to about 30 mGy/yr in vivo and up to 50 mGy in vitro were investigated by the author and other scientists. Results are comparable and dose effect curves reveal following shapes; within the normal burden and up to 2-10 mGy/yr in vivo rates they increase sharply to about 3-6 times the lowest values; subsequent doses either from natural, occupational or accidental exposures up to about 30 mGy/yr yield either constant aberration rates, assuming a plateau, or perhaps even a decrease. In vitro experiments show comparable results up to 50 mGy. Other biological effects seem to have similar dose dependencies. The non-linearity of low-dose effects can be explained by induction of repair enzymes at certain damage to the DNA. This hypothesis is sustained experimentally and theoretically by several papers in literature. (author). 14 refs., 5 figs

  15. Low and very low doses, new recommendations?

    International Nuclear Information System (INIS)

    Foucher, N.

    1999-01-01

    The topic of the seminar organized by the world council of nuclear workers (WONUC) was the effects of low or very low doses on human health. Discussions centred round the linearity of the relation between dose and effect in the evaluation and management of the health hazard. The recommendations proposed by ICPR (international commission for radiological protection) are based on this linearity as a precaution. On the one hand it is remembered that low dose irradiation might be beneficial. It has been proved that the irradiation of the whole body is efficient in case of Hodgkin lymphoma. On the other hand it is remembered that doses as low as 10 mSv in utero have led to an excess of cancer in children. Studies based on experimentally radio-induced cancers have been carried out in Japan, China, Canada and France.Their results seem to be not consistent with the hypothesis of linearity. During the last decade a lot of work has been made but a conclusion is far to be reached, it is said that the American department of energy (DOE) has invited bids in 1999 to launch research programs in order to clarify the situation. (A.C.)

  16. Biological Effects of Low-Dose Exposure

    CERN Document Server

    Komochkov, M M

    2000-01-01

    On the basis of the two-protection reaction model an analysis of stochastic radiobiological effects of low-dose exposure of different biological objects has been carried out. The stochastic effects are the results published in the last decade: epidemiological studies of human cancer mortality, the yield of thymocyte apoptosis of mice and different types of chromosomal aberrations. The results of the analysis show that as dependent upon the nature of biological object, spontanous effect, exposure conditions and radiation type one or another form dose - effect relationship is realized: downwards concave, near to linear and upwards concave with the effect of hormesis included. This result testifies to the incomplete conformity of studied effects of 1990 ICRP recomendations based on the linear no-threshold hypothesis about dose - effect relationship. Because of this the methodology of radiation risk estimation recomended by ICRP needs more precisian and such quantity as collective dose ought to be classified into...

  17. Multidisciplinary European Low Dose Initiative (MELODI). Strategic research agenda for low dose radiation risk research

    Energy Technology Data Exchange (ETDEWEB)

    Kreuzer, M. [Federal Office for Radiation Protection, BfS, Department of Radiation Protection and Health, Neuherberg (Germany); Auvinen, A. [University of Tampere, Tampere (Finland); STUK, Helsinki (Finland); Cardis, E. [ISGlobal, Barcelona Institute for Global Health, Barcelona (Spain); Durante, M. [Institute for Fundamental Physics and Applications, TIFPA, Trento (Italy); Harms-Ringdahl, M. [Stockholm University, Centre for Radiation Protection Research, Stockholm (Sweden); Jourdain, J.R. [Institute for Radiological Protection and Nuclear Safety, IRSN, Fontenay-aux-roses (France); Madas, B.G. [MTA Centre for Energy Research, Environmental Physics Department, Budapest (Hungary); Ottolenghi, A. [University of Pavia, Physics Department, Pavia (Italy); Pazzaglia, S. [Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Rome (Italy); Prise, K.M. [Queens University Belfast, Belfast (United Kingdom); Quintens, R. [Belgian Nuclear Research Centre, SCK-CEN, Mol (Belgium); Sabatier, L. [French Atomic Energy Commission, CEA, Paris (France); Bouffler, S. [Public Health England, PHE, Chilton (United Kingdom)

    2018-03-15

    MELODI (Multidisciplinary European Low Dose Initiative) is a European radiation protection research platform with focus on research on health risks after exposure to low-dose ionising radiation. It was founded in 2010 and currently includes 44 members from 18 countries. A major activity of MELODI is the continuous development of a long-term European Strategic Research Agenda (SRA) on low-dose risk for radiation protection. The SRA is intended to identify priorities for national and European radiation protection research programs as a basis for the preparation of competitive calls at the European level. Among those key priorities is the improvement of health risk estimates for exposures close to the dose limits for workers and to reference levels for the population in emergency situations. Another activity of MELODI is to ensure the availability of European key infrastructures for research activities, and the long-term maintenance of competences in radiation research via an integrated European approach for training and education. The MELODI SRA identifies three key research topics in low dose or low dose-rate radiation risk research: (1) dose and dose rate dependence of cancer risk, (2) radiation-induced non-cancer effects and (3) individual radiation sensitivity. The research required to improve the evidence base for each of the three key topics relates to three research lines: (1) research to improve understanding of the mechanisms contributing to radiogenic diseases, (2) epidemiological research to improve health risk evaluation of radiation exposure and (3) research to address the effects and risks associated with internal exposures, differing radiation qualities and inhomogeneous exposures. The full SRA and associated documents can be downloaded from the MELODI website (http://www.melodi-online.eu/sra.html). (orig.)

  18. Implications for human and environmental health of low doses of ionising radiation

    International Nuclear Information System (INIS)

    Mothersill, Carmel; Seymour, Colin

    2014-01-01

    The last 20 years have seen a major paradigm shift in radiation biology. Several discoveries challenge the DNA centric view which holds that DNA damage is the critical effect of radiation irrespective of dose. This theory leads to the assumption that dose and effect are simply linked – the more energy deposition, the more DNA damage and the greater the biological effect. This is embodied in radiation protection (RP) regulations as the linear-non-threshold (LNT) model. However the science underlying the LNT model is being challenged particularly in relation to the environment because it is now clear that at low doses of concern in RP, cells, tissues and organisms respond to radiation by inducing responses which are not readily predictable by dose. These include adaptive responses, bystander effects, genomic instability and low dose hypersensitivity, and are commonly described as stress responses, while recognizing that “stress” can be good as well as bad. The phenomena contribute to observed radiation responses and appear to be influenced by genetic, epigenetic and environmental factors, meaning that dose and response are not simply related. The question is whether our discovery of these phenomena means that we need to re-evaluate RP approaches. The so-called “non-targeted” mechanisms mean that low dose radiobiology is very complex and supra linear or sub-linear (even hormetic) responses are possible but their occurrence is unpredictable for any given system level. Issues which may need consideration are synergistic or antagonistic effects of other pollutants. RP, at present, only looks at radiation dose but the new (NTE) radiobiology means that chemical or physical agents, which interfere with tissue responses to low doses of radiation, could critically modulate the predicted risk. Similarly, the “health” of the organism could determine the effect of a given low dose by enabling or disabling a critical response. These issues will be discussed

  19. Advanced Computational Approaches for Characterizing Stochastic Cellular Responses to Low Dose, Low Dose Rate Exposures

    Energy Technology Data Exchange (ETDEWEB)

    Scott, Bobby, R., Ph.D.

    2003-06-27

    OAK - B135 This project final report summarizes modeling research conducted in the U.S. Department of Energy (DOE), Low Dose Radiation Research Program at the Lovelace Respiratory Research Institute from October 1998 through June 2003. The modeling research described involves critically evaluating the validity of the linear nonthreshold (LNT) risk model as it relates to stochastic effects induced in cells by low doses of ionizing radiation and genotoxic chemicals. The LNT model plays a central role in low-dose risk assessment for humans. With the LNT model, any radiation (or genotoxic chemical) exposure is assumed to increase one¡¯s risk of cancer. Based on the LNT model, others have predicted tens of thousands of cancer deaths related to environmental exposure to radioactive material from nuclear accidents (e.g., Chernobyl) and fallout from nuclear weapons testing. Our research has focused on developing biologically based models that explain the shape of dose-response curves for low-dose radiation and genotoxic chemical-induced stochastic effects in cells. Understanding the shape of the dose-response curve for radiation and genotoxic chemical-induced stochastic effects in cells helps to better understand the shape of the dose-response curve for cancer induction in humans. We have used a modeling approach that facilitated model revisions over time, allowing for timely incorporation of new knowledge gained related to the biological basis for low-dose-induced stochastic effects in cells. Both deleterious (e.g., genomic instability, mutations, and neoplastic transformation) and protective (e.g., DNA repair and apoptosis) effects have been included in our modeling. Our most advanced model, NEOTRANS2, involves differing levels of genomic instability. Persistent genomic instability is presumed to be associated with nonspecific, nonlethal mutations and to increase both the risk for neoplastic transformation and for cancer occurrence. Our research results, based on

  20. Low dose irradiation facilitates hepatocellular carcinoma genesis involving HULC.

    Science.gov (United States)

    Li, Yuan; Ge, Chang; Feng, Guoxing; Xiao, Huiwen; Dong, Jiali; Zhu, Changchun; Jiang, Mian; Cui, Ming; Fan, Saijun

    2018-03-24

    Irradiation exposure positive correlates with tumor formation, such as breast cancer and lung cancer. However, whether low dose irradiation induces hepatocarcinogenesis and the underlying mechanism remain poorly defined. In the present study, we reported that low dose irradiation facilitated the proliferation of hepatocyte through up-regulating HULC in vitro and in vivo. Low dose irradiation exposure elevated HULC expression level in hepatocyte. Deletion of heightened HULC erased the cells growth accelerated following low dose irradiation exposure. CDKN1, the neighbor gene of HULC, was down-regulated by overexpression of HULC following low dose irradiation exposure via complementary base pairing, resulting in promoting cell cycle process. Thus, our findings provide new insights into the mechanism of low dose irradiation-induced hepatocarcinogenesis through HULC/CDKN1 signaling, and shed light on the potential risk of low dose irradiation for the development of hepatocellular carcinoma in pre-clinical settings. © 2018 Wiley Periodicals, Inc.

  1. low dose irradiation growth in zirconium

    International Nuclear Information System (INIS)

    Fortis, A.M.

    1987-01-01

    Low dose neutron irradiation growth in textured and recrystallized zirconium, is studied, at the Candu Reactors Calandria temperature (340 K) and at 77 K. It was necessary to design and build 1: A facility to irradiate at high temperatures, which was installed in the Argentine Atomic Energy Commission's RA1 Reactor; 2: Devices to carry out thermal recoveries, and 3: Devices for 'in situ' measurements of dimensional changes. The first growth kinetics curves were obtained at 365 K and at 77 K in a cryostat under neutron fluxes of similar spectra. Irradiation growth experiments were made in zirconium doped with fissionable material (0,1 at % 235 U). In this way an equivalent dose two orders of magnitude greater than the reactor's fast neutrons dose was obtained, significantly reducing the irradiation time. The specimens used were bimetallic couples, thus obtaining a great accuracy in the measurements. The results allow to determine that the dislocation loops are the main cause of irradiation growth in recrystallized zirconium. Furthermore, it is shown the importance of 'in situ' measurements as a way to avoid the effect that temperature changes have in the final growth measurement; since they can modify the residual stresses and the overconcentrations of defects. (M.E.L.) [es

  2. Radioresponsiveness at low doses. Hyper-radiosensitivity and increased radioresistance in mammalian cells

    International Nuclear Information System (INIS)

    Skov, K.A.

    1999-01-01

    The rationale for and importance of research on effects after radiation at 'low doses' are outlined. Such basic radiobiological studies on induction of repair enzymes, protective mechanisms, priming, and hypersensitivity are certainly all relevant to treatment of cancer (see Section 1, Studies at low doses - relevance to cancer treatment). Included are examples from many groups, using various endpoints to address the possibility of an induced resistance, which has been compared to the adaptive response [M.C. Joiner, P. Lambin, E.P. Malaise, T. Robson, J.E. Arrand, K.A. Skov, B. Marples, Hypersensitivity to very low single radiation doses: its relationship to the adaptive response and induced radioresistance, Mutat. Res. 358 (1996) 171-183.]. This is not intended to be an exhaustive review - rather a re-introduction of concepts such as priming and a short survey of molecular approaches to understanding induced resistance. New data on the response of HT29 cells after treatment (priming) with co-cultured activated neutrophils are included, with protection against X-rays (S1). Analysis of previously published results in various cells lines in terms of increased radioresistance (IRR)/intrinsic sensitivity are presented which complement a study on human tumour lines [P. Lambin, E.P. Malaise, M.C. Joiner, Might intrinsic radioresistance of human tumour cells be induced by radiation?, Int. Radiat. Biol. 69 (1996) 279-290]. It is not feasible to extrapolate to low doses from studies at high doses. The biological responses probably vary with dose, LET, and have variable time frames. The above approaches may lead to new types of treatment, or additional means to assess radioresponsiveness of tumours. Studies in many areas of biology would benefit from considerations of different dose regions, as the biological responses vary with dose. There may also be some implications in the fields of radiation protection and carcinogenesis, and the extensions of concepts of hyper

  3. Effects of low doses of ionizing radiation

    International Nuclear Information System (INIS)

    Masse, R.

    2006-01-01

    Several groups of human have been irradiated by accidental or medical exposure, if no gene defect has been associated to these exposures, some radioinduced cancers interesting several organs are observed among persons exposed over 100 to 200 mSv delivered at high dose rate. Numerous steps are now identified between the initial energy deposit in tissue and the aberrations of cell that lead to tumors but the sequence of events and the specific character of some of them are the subject of controversy. The stake of this controversy is the risk assessment. From the hypothesis called linear relationship without threshold is developed an approach that leads to predict cancers at any tiny dose without real scientific foundation. The nature and the intensity of biological effects depend on the quantity of energy absorbed in tissue and the modality of its distribution in space and time. The probability to reach a target (a gene) associated to the cancerating of tissue is directly proportional to the dose without any other threshold than the quantity of energy necessary to the effect, its probability of effect can be a more complex function and depends on the quality of the damage produced as well as the ability of the cell to repair the damage. These two parameters are influenced by the concentration of initial injuries in the target so by the quality of radiation and by the dose rate. The mechanisms of defence explain the low efficiency of radiation as carcinogen and then the linearity of effects in the area of low doses is certainly the least defensible scientific hypothesis for the prediction of the risks. (N.C.)

  4. Characteristics of repair following very low doses

    International Nuclear Information System (INIS)

    Braby, L.A.; Metting, N.F.; Nelson, J.M.

    1987-01-01

    The effects of ionizing radiation on living systems being with the physical processes of energy deposition and develop through many stages of chemical reaction and biological response. The modeling effort attempts to organize the available data and theories of all of these stages into self-consistent models that can be compared and tested. In some cases, important differences among models result in only small differences in cell survival within the ranges of dose and dose rate that are normally investigated. To overcome this limitation, new ways of irradiating cells at extremes of dose rate, or ways of evaluating the effects of very small doses, are developed. Mathematical modeling and cellular studies complement each other. It has recently been found that some mechanisms are not adequate to account for the interaction of dose and repair time as they affect the reproductive survival of plateau-phase Chinese hamster ovary (CHO) cells. Repair of radiation-induced cellular damage plays a central role in the survival of cells exposed to doses of 1 Gy or more. This repair is responsible for the dose rate, split-dose and delayed plating effect and can be evaluated. Because split-dose and dose-rate experiments involve repair during irradiation and delayed plating experiments involve repair after irradiation is completed, it was originally thought that different repair processes were involved. It is now clear that this is not necessarily the case. Appropriately designed models can account for observed effects at conventional doses (1 Gy or more) whether they assume all damage is lethal unless repaired or some damage is innocuous unless it interacts with additional damage. The fact that the survival following a plating delay is always less than the survival following immediate plating at low doses indicates that the damage produced is probably not potentially lethal

  5. Effects of low dose mitomycin C on experimental tumor radiotherapy

    International Nuclear Information System (INIS)

    Yang Jianzheng; Liang Shuo; Qu Yaqin; Pu Chunji; Zhang Haiying; Wu Zhenfeng; Wang Xianli

    2001-01-01

    Objective: To evaluate the possibility of low dose mitomycin C(MMC) as an adjunct therapy for radiotherapy. Methods: Change in tumor size tumor-bearing mice was measured. Radioimmunoassay was used to determine immune function of mice. Results: Low dose Mac's pretreatment reduced tumor size more markedly than did radiotherapy only. The immune function in mice given with low dose MMC 12h before radiotherapy was obviously higher than that in mice subjected to radiotherapy only (P<0.05), and was close to that in the tumor-bearing mice before radiotherapy. Conclusion: Low dose MMC could improve the radiotherapy effect. Pretreatment with low dose MMC could obviously improve the immune suppression state in mice caused by radiotherapy. The mechanism of its improvement of radiotherapeutic effect by low dose of MMC might be due to its enhancement of immune function and induction of adaptive response in tumor-bearing mice

  6. Low-dose effects of hormones and endocrine disruptors.

    Science.gov (United States)

    Vandenberg, Laura N

    2014-01-01

    Endogenous hormones have effects on tissue morphology, cell physiology, and behaviors at low doses. In fact, hormones are known to circulate in the part-per-trillion and part-per-billion concentrations, making them highly effective and potent signaling molecules. Many endocrine-disrupting chemicals (EDCs) mimic hormones, yet there is strong debate over whether these chemicals can also have effects at low doses. In the 1990s, scientists proposed the "low-dose hypothesis," which postulated that EDCs affect humans and animals at environmentally relevant doses. This chapter focuses on data that support and refute the low-dose hypothesis. A case study examining the highly controversial example of bisphenol A and its low-dose effects on the prostate is examined through the lens of endocrinology. Finally, the chapter concludes with a discussion of factors that can influence the ability of a study to detect and interpret low-dose effects appropriately. © 2014 Elsevier Inc. All rights reserved.

  7. Endometrial safety of ultra-low-dose estradiol vaginal tablets

    DEFF Research Database (Denmark)

    Simon, James; Nachtigall, Lila; Ulrich, Lian G

    2010-01-01

    To evaluate the endometrial hyperplasia and carcinoma rate after 52-week treatment with ultra-low-dose 10-microgram 17ß-estradiol vaginal tablets in postmenopausal women with vaginal atrophy.......To evaluate the endometrial hyperplasia and carcinoma rate after 52-week treatment with ultra-low-dose 10-microgram 17ß-estradiol vaginal tablets in postmenopausal women with vaginal atrophy....

  8. Endometrial safety of ultra-low-dose estradiol vaginal tablets

    DEFF Research Database (Denmark)

    Simon, James; Nachtigall, Lila; Ulrich, Lian G

    2010-01-01

    To evaluate the endometrial hyperplasia and carcinoma rate after 52-week treatment with ultra-low-dose 10-microgram 17β-estradiol vaginal tablets in postmenopausal women with vaginal atrophy.......To evaluate the endometrial hyperplasia and carcinoma rate after 52-week treatment with ultra-low-dose 10-microgram 17β-estradiol vaginal tablets in postmenopausal women with vaginal atrophy....

  9. Study of genomic instability induced by low dose ionizing radiation

    International Nuclear Information System (INIS)

    Seoane, A.; Crudeli, C.; Dulout, F.

    2006-01-01

    The crews of commercial flights and services staff of radiology and radiotherapy from hospitals are exposed to low doses of ionizing radiation. Genomic instability includes those adverse effects observed in cells, several generations after the exposure occurred. The purpose of this study was to analyze the occurrence of genomic instability by very low doses of ionizing radiation [es

  10. Regeneration of Murine Hair Follicles is Inhibited by Low-Dose-Rate Gamma Irradiation.

    Science.gov (United States)

    Sugaya, Kimihiko; Hirobe, Tomohisa; Ishihara, Yoshie; Inoue, Sonoe

    2016-10-01

    To determine whether the effects of low-dose-rate gamma (γ) irradiation are identifiable in the regeneration of murine hair follicles, we irradiated whole bodies of C57BL/10JHir mice in the first telogen phase of the hair cycle with 137 Cs γ-rays. The mice were examined for effects on hair follicles, including number, morphology, and pigmentation in the second anagen phase. Effects of γ-radiation on melanocyte stem cells were also investigated by the indirect immunolabeling of tyrosinase-related protein 2 (TRP2). Irradiated skin showed a decrease in hair follicle density and the induction of curved hair follicles along with the presence of white hairs and hypopigmented hair bulbs. There was a small, but not significant, change in the number of TRP2-positive melanocyte stem cells in the hair bulge region of the irradiated skin. These results suggest that low-dose rate γ-irradiation does not deplete melanocyte stem cells, but can damage stem cells and progenitors for both keratinocytes and melanocytes, thereby affecting the structure and pigmentation of regenerated hair follicles in the 2 nd anagen phase.

  11. Biological responses to low dose rate gamma radiation

    International Nuclear Information System (INIS)

    Magae, Junji; Ogata, Hiromitsu

    2003-01-01

    Linear non-threshold (LNT) theory is a basic theory for radioprotection. While LNT dose not consider irradiation time or dose-rate, biological responses to radiation are complex processes dependent on irradiation time as well as total dose. Moreover, experimental and epidemiological studies that can evaluate LNT at low dose/low dose-rate are not sufficiently accumulated. Here we analyzed quantitative relationship among dose, dose-rate and irradiation time using chromosomal breakage and proliferation inhibition of human cells as indicators of biological responses. We also acquired quantitative data at low doses that can evaluate adaptability of LNT with statistically sufficient accuracy. Our results demonstrate that biological responses at low dose-rate are remarkably affected by exposure time, and they are dependent on dose-rate rather than total dose in long-term irradiation. We also found that change of biological responses at low dose was not linearly correlated to dose. These results suggest that it is necessary for us to create a new model which sufficiently includes dose-rate effect and correctly fits of actual experimental and epidemiological results to evaluate risk of radiation at low dose/low dose-rate. (author)

  12. Acomparative Study Comparing Low-dose Step-up Versus Step-down in Polycystic Ovary Syndrome Resistant to Clomiphene

    Directory of Open Access Journals (Sweden)

    S Peivandi

    2010-03-01

    Full Text Available Introduction: Polycystic ovary syndrome(PCOS is one of the most common cause of infertility in women. clomiphene is the first line of treatment. however 20% of patients are resistant to clomiphene. because of follicular hypersensitivity to gonadotropins in pcod, multiple follicular growth and development occurs which is cause of OHSS and multiple pregnancy. Our aim of this random and clinical study was comparation between step-down and low dose step-up methods for induction ovulation in clomiphene resistant. Methods: 60 cases were included 30 women in low-dose step-up group and 30 women in step-down group. In low-dose step-up HMG 75u/d and in step-down HMG 225u/d was started on 3th days of cycle, monitoring with vaginal sonography was done on 8th days of cycle. When follicle with>14 mm in diameter was seen HMG dose was continued in low-dose step-up and was decreased in step-down group. When follicle reached to 18mm in diameter, amp HCG 10000 unit was injected and IUI was performed 36 hours later. Results: Number of HMG ampules, number of follicles> 14mm on the day of HCG injection and level of serum estradiol was greater in low dose step up protocol than step down protocol(p<0/0001. Ovulation rate and pregnancy rate was greater in lowdose step up group than step down group with significant difference (p<0/0001. Conclusion: Our study showed that low-dose step-up regimen with HMG is effective for stimulating ovulation and clinical pregnancy but in view of monofollicular growth, the step down method was more effective and safe. In our study multifolliular growth in step-up method was higher than step-down method. We can predict possibility of Ovarian Hyperstimulation Syndrome syndrome in highly sensitive PCOS patients.

  13. Low dose effects of ionizing radiations in in vitro and in vivo biological systems: a multi-scale approach study

    International Nuclear Information System (INIS)

    Antoccia, A.; Berardinelli, F.; Argazzi, E.; Balata, M.; Bedogni, R.

    2011-01-01

    Long-term biological effects of low-dose radiation are little known nowadays and its carcinogenic risk is estimated on the assumption that risk remains linearly proportional to the radiation dose down to low-dose levels. However in the last 20 years this hypothesis has gradually begun to seem in contrast with a huge collection of experimental evidences, which has shown the presence of plethora of non-linear phenomena (including hypersensitivity and induced radioresistance, adaptive response, and non-targeted phenomena like bystander effect and genomic instability) occurring after low-dose irradiation. These phenomena might imply a non-linear behaviour of cancer risk curves in the low-dose region and question the validity of the Linear No-Threshold (LNT) model currently used for cancer risk assessment through extrapolation from existing high-dose data. Moreover only few information is available regarding the effects induced on cryo preserved cells by multi-year background radiation exposure, which might induce a radiation-damage accumulation, due to the inhibition of cellular repair mechanisms. In this framework, the multi-year Excalibur (Exposure effects at low doses of ionizing radiation in biological culture) experiment, funded by INFN-CNS5, has undertaken a multi-scale approach investigation on the biological effects induced in in vitro and in vivo biological systems, in culture and cryo preserved conditions, as a function of radiation quality (X/γ-rays, protons, He-4 ions of various energies) and dose, with particular emphasis on the low-dose region and non-linear phenomena, in terms of different biological endpoints.

  14. Cancer risk of low dose/low dose rate radiation: a meta-analysis of cancer data of mammals exposed to low doses of radiation

    International Nuclear Information System (INIS)

    Ogata, Hiromitsu; Magae, Junji

    2008-01-01

    Full text: Linear No Threshold (LNT) model is a basic theory for radioprotection, but the adaptability of this hypothesis to biological responses at low doses or at low dose rates is not sufficiently investigated. Simultaneous consideration of the cumulative dose and the dose rate is necessary for evaluating the risk of long-term exposure to ionizing radiation at low dose. This study intends to examine several numerical relationships between doses and dose rates in biological responses to gamma radiation. Collected datasets on the relationship between dose and the incidence of cancer in mammals exposed to low doses of radiation were analysed using meta-regression models and modified exponential (MOE) model, which we previously published, that predicts irradiation time-dependent biological response at low dose rate ionizing radiation. Minimum doses of observable risk and effective doses with a variety of dose rates were calculated using parameters estimated by fitting meta-regression models to the data and compared them with other statistical models that find values corresponding to 'threshold limits'. By fitting a weighted regression model (fixed-effects meta-regression model) to the data on risk of all cancers, it was found that the log relative risk [log(RR)] increased as the total exposure dose increased. The intersection of this regression line with the x-axis denotes the minimum dose of observable risk. These estimated minimum doses and effective doses increased with decrease of dose rate. The goodness of fits of MOE-model depended on cancer types, but the total cancer risk is reduced when dose rates are very low. The results suggest that dose response curve for cancer risk is remarkably affected by dose rate and that dose rate effect changes as a function of dose rate. For scientific discussion on the low dose exposure risk and its uncertainty, the term 'threshold' should be statistically defined, and dose rate effects should be included in the risk

  15. Induction of somatic mutations by low-dose X-rays: the challenge in recognizing radiation-induced events.

    Science.gov (United States)

    Nagashima, Haruki; Shiraishi, Kumiko; Ohkawa, Saori; Sakamoto, Yuki; Komatsu, Kenshi; Matsuura, Shinya; Tachibana, Akira; Tauchi, Hiroshi

    2017-10-19

    It is difficult to distinguish radiation-induced events from spontaneous events during induction of stochastic effects, especially in the case of low-dose or low-dose-rate exposures. By using a hypersensitive system for detecting somatic mutations at the HPRT1 locus, we investigated the frequency and spectrum of mutations induced by low-dose X-rays. The mutant frequencies induced by doses of >0.15 Gy were statistically significant when compared with the spontaneous frequency, and a clear dose dependency was also observed for mutant frequencies at doses of >0.15 Gy. In contrast, mutant frequencies at doses of 0.2 Gy. Our observations suggest that there could be a critical dose for mutation induction at between 0.1 Gy and 0.2 Gy, where mutagenic events are induced by multiple DNA double-strand breaks (DSBs). These observations also suggest that low-dose radiation delivered at doses of <0.1 Gy may not result in DSB-induced mutations but may enhance spontaneous mutagenesis events. © The Author 2017. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

  16. Mechanisms of Enhanced Cell Killing at Low Doses: Implications for Radiation Risk

    International Nuclear Information System (INIS)

    Johnston, Peter J.; Wilson, George D.

    2003-01-01

    We have shown that cell lethality actually measured after exposure to low-doses of low-LET radiation, is markedly enhanced relative to the cell lethality previously expected by extrapolation of the high-dose cell-killing response. Net cancer risk is a balance between cell transformation and cell kill and such enhanced lethality may more than compensate for transformation at low radiation doses over a least the first 10 cGy of low-LET exposure. This would lead to a non-linear, threshold, dose-risk relationship. Therefore our data imply the possibility that the adverse effects of small radiation doses (<10 cGy) could be overestimated in specific cases. It is now important to research the mechanisms underlying the phenomenon of low-dose hypersensitivity to cell killing, in order to determine whether this can be generalized to safely allow an increase in radiation exposure limits. This would have major cost-reduction implications for the whole EM program

  17. Risk of cancer subsequent to low-dose radiation

    International Nuclear Information System (INIS)

    Warren, S.

    1980-01-01

    The author puts low dose irradiation risks in perspective using average background radiation doses for standards. He assailed irresponsible media coverage during the height of public interest in the Three-Mile Island Reactor incident

  18. Radiation effects after low dose chronic long-term exposure

    International Nuclear Information System (INIS)

    Fliedner, T.M.; Friesecke, I.

    1997-01-01

    This document approaches the radiation effects after low dose chronic long-term exposure, presenting examples occurred, the pathophysiologic mechanisms for cell system tolerance in elevated radiation fields, and the diagnostic and therapeutic possibilities

  19. Topics on study of low dose-effect relationship

    International Nuclear Information System (INIS)

    Yamada, Takeshi; Ohyama, Harumi

    1999-01-01

    It is not exceptional but usually observed that a dose-effect relationship in biosystem is not linear. Sometimes, the low dose-effect relationship appears entirely contrary to the expectation from high dose-effect. This is called a 'hormesis' phenomena. A high dose irradiation inflicts certainly an injury on biosystem. No matter how low the dose may be, an irradiation might inflict some injury on biosystem according to Linear Non-Threshold hypothesis(LNT). On the contrary to the expectation, a low dose irradiation stimulates immune system, and promotes cell proliferation. This is called 'radiation hormesis'. The studies of the radiation hormesis are made on from four points of view as follows: (1) radiation adaptive response, (2) revitalization caused by a low dose stimulation, (3) a low dose response unexpected from the LNT hypothesis, (4) negation of the LNT hypothesis. The various empirical proofs of radiation hormesis are introduced in the report. (M . Suetake)

  20. Development of Plant Application Technique of Low Dose Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Byung Yeoup; Kim, Jae Sung; Lim, Yong Taek (and others)

    2007-07-15

    The project was carried out to achieve three aims. First, development of application techniques of cell-stimulating effects by low-dose radiation. Following irradiation with gamma-rays of low doses, beneficial effects in crop germination, early growth, and yield were investigated using various plant species and experimental approaches. For the actual field application, corroborative studies were also carried out with a few concerned experimental stations and farmers. Moreover, we attempted to establish a new technique of cell cultivation for industrial mass-production of shikonin, a medicinal compound from Lithospermum erythrorhizon and thereby suggested new application fields for application techniques of low-dose radiation. Second, elucidation of action mechanisms of ionizing radiation in plants. By investigating changes in plant photosynthesis and physiological metabolism, we attempted to elucidate physiological activity-stimulating effects of low-dose radiation and to search for radiation-adaptive cellular components. Besides, analyses of biochemical and molecular biological mechanisms for stimulus-stimulating effects of low-dose radiation were accomplished by examining genes and proteins inducible by low-dose radiation. Third, development of functional crop plants using radiation-resistant factors. Changes in stress-tolerance of plants against environmental stress factors such as light, temperature, salinity and UV-B stress after exposed to low-dose gamma-rays were investigated. Concerned reactive oxygen species, antioxidative enzymes, and antioxidants were also analyzed to develop high value-added and environment-friendly functional plants using radiation-resistant factors. These researches are important to elucidate biological activities increased by low-dose radiation and help to provide leading technologies for improvement of domestic productivity in agriculture and development of high value-added genetic resources.

  1. Low dose rate Ir-192 interstitial brachytherapy for prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Oki, Yosuke; Dokiya, Takushi; Yorozu, Atsunori; Suzuki, Takayuki; Saito, Shiro; Monma, Tetsuo; Ohki, Takahiro [National Tokyo Medical Center (Japan); Murai, Masaru; Kubo, Atsushi

    2000-04-01

    From December 1997 through January 1999, fifteen prostatic cancer patients were treated with low dose rate Ir-192 interstitial brachytherapy using TRUS and perineal template guidance without external radiotherapy. Up to now, as no apparent side effects were found, the safety of this treatment is suggested. In the future, in order to treat prostatic cancer patients with interstitial brachytherapy using I-125 or Pd-103, more investigation for this low dose rate Ir-192 interstitial brachytherapy is needed. (author)

  2. Development of Plant Application Technique of Low Dose Radiation

    International Nuclear Information System (INIS)

    Chung, Byung Yeoup; Kim, Jae Sung; Lim, Yong Taek

    2007-07-01

    The project was carried out to achieve three aims. First, development of application techniques of cell-stimulating effects by low-dose radiation. Following irradiation with gamma-rays of low doses, beneficial effects in crop germination, early growth, and yield were investigated using various plant species and experimental approaches. For the actual field application, corroborative studies were also carried out with a few concerned experimental stations and farmers. Moreover, we attempted to establish a new technique of cell cultivation for industrial mass-production of shikonin, a medicinal compound from Lithospermum erythrorhizon and thereby suggested new application fields for application techniques of low-dose radiation. Second, elucidation of action mechanisms of ionizing radiation in plants. By investigating changes in plant photosynthesis and physiological metabolism, we attempted to elucidate physiological activity-stimulating effects of low-dose radiation and to search for radiation-adaptive cellular components. Besides, analyses of biochemical and molecular biological mechanisms for stimulus-stimulating effects of low-dose radiation were accomplished by examining genes and proteins inducible by low-dose radiation. Third, development of functional crop plants using radiation-resistant factors. Changes in stress-tolerance of plants against environmental stress factors such as light, temperature, salinity and UV-B stress after exposed to low-dose gamma-rays were investigated. Concerned reactive oxygen species, antioxidative enzymes, and antioxidants were also analyzed to develop high value-added and environment-friendly functional plants using radiation-resistant factors. These researches are important to elucidate biological activities increased by low-dose radiation and help to provide leading technologies for improvement of domestic productivity in agriculture and development of high value-added genetic resources

  3. Review of European research trends of low dose radiation risk

    International Nuclear Information System (INIS)

    Iwasaki, Toshiyasu; Yoshida, Kazuo

    2010-01-01

    Large research projects on low dose radiation effects in Europe and US over the past decade have provided limited scientific knowledge which could underpin the validation of radiation protection systems. Recently in Europe, there have been repeated discussions and dialogues to improve the situation, and as the consequence, the circumstances surrounding low dose radiation risks are changing. In 2009, Multidisciplinary European Low Dose Initiative (MELODI) was established as a trans-national organization capable of ensuring appropriate governance of research in the pursuit of a long term shared vision, and Low Dose Research towards Multidisciplinary Integration (DoReMi) network was launched in 2010 to achieve fairly short term results in order to prove the validity of the MELODI approach. It is expected to be very effective and powerful activities to facilitate the reduction of uncertainties in the understanding of low dose risks, but the regulatory requests rushing the reinforcement of radiological protection regulations based on the precautional principles are more increasing. To develop reasonable radiological protection systems based on scientific evidences, we need to accelerate to collect scientific evidences which could directly underpin more appropriate radiation protection systems even in Japan. For the purpose, we Japan need to develop from an independent standpoint and share as a multidisciplinary vision a long term and holistic research strategy which enables to enhance Japanese advantages such as low dose rate facilities and animal facilities, as soon as possible. (author)

  4. Ameliorative effects of low dose/low dose-rate irradiation on reactive oxygen species-related diseases model mice

    International Nuclear Information System (INIS)

    Nomura, Takaharu

    2008-01-01

    Living organisms have developed complex biological system which protects themselves against environmental radiation, and irradiation with proper dose, dose-rate and irradiation time can stimulate their biological responses against oxidative stress evoked by the irradiation. Because reactive oxygen species are involved in various human diseases, non-toxic low dose/low dose-rate radiation can be utilized for the amelioration of such diseases. In this study, we used mouse experimental models for fatty liver, nephritis, diabetes, and ageing to elucidate the ameliorative effect of low dose/low dose-rate radiation in relation to endogenous antioxidant activity. Single irradiation at 0.5 Gy ameliorates carbon tetrachloride-induced fatty liver. The irradiation increases hepatic anti-oxidative system involving glutathione and glutathione peroxidase, suggesting that endogenous radical scavenger is essential for the ameliorative effect of low dose radiation on carbon tetrachloride-induced fatty liver. Single irradiation at 0.5 Gy ameliorates ferric nitrilotriacetate-induced nephritis. The irradiation increases catalase and decreases superoxide dismutase in kidney. The result suggests that low dose radiation reduced generation of hydroxide radical generation by reducing cellular hydroperoxide level. Single irradiation at 0.5 Gy at 12 week of age ameliorates incidence of type I diabetes in non-obese diabetic (NOD) mice through the suppression of inflammatory activity of splenocytes, and resultant apoptosis of β-cells in pancreas. The irradiation activities of superoxide dismutase and catalase, which coordinately diminish intracellular reactive oxygen species. Continuous irradiation at 0.70 mGy/hr from 10 week of age elongates life span, and suppresses alopecia in type II diabetesmice. The irradiation improved glucose clearance without affecting insulin-resistance, and increased pancreatic catalase activity. The results suggest that continuous low dose-rate irradiation protect

  5. Low Dose Suppression of Neoplastic Transformation in Vitro

    Energy Technology Data Exchange (ETDEWEB)

    John Leslie Redpath

    2012-05-01

    This grant was to study the low dose suppression of neoplastic transformation in vitro and the shape of the dose-response curve at low doses and dose-rates of ionizing radiation. Previous findings had indicated a suppression of transformation at dose <10cGy of low-LET radiation when delivered at high dose-rate. The present study indicates that such suppression extends out to doses in excess of 100cGy when the dose (from I-125 photons) is delivered at dose-rates as low as 0.2 mGy/min and out to in excess of {approx}25cGy the highest dose studied at the very low dose-rate of 0.5 mGy/day. We also examined dose-rate effects for high energy protons (which are a low-LET radiation) and suppression was evident below {approx}10cGy for high dose-rate delivery and at least out to 50cGy for low dose-rate (20cGy/h) delivery. Finally, we also examined the effect of low doses of 1 GeV/n iron ions (a high-LET radiation) delivered at high dose-rate on transformation at low doses and found a suppression below {approx}10cGy that could be attributable to an adaptive response in bystander cells induced by the associated low-LET delta rays. These results have implications for cancer risk assessment at low doses.

  6. Genetic Factors Affecting Susceptibility to Low Dose & Low Dose-Rate Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Bedford, Joel

    2014-04-18

    Our laboratory has, among other things, developed and used the gamma H2AX focus assay and other chromosomal and cell killing assays to show that differences in this DNA double strand break (dsb) related response can be clearly and distinctly demonstrated for cells which are mildly hyper-radiosensitive such as those associated with A-T heterozygosity. We have found this level of mild hypersensitivity for cells from some 20 to 30 % of apparently normal individuals and from apparently normal parents of Retinoblastoma patients. We found significant differences in gene expression in somatic cells from unaffected parents of Rb patients as compared with normal controls, suggesting that these parents may harbor some as yet unidentified genetic abnormality. In other experiments we sought to determine the extent of differences in normal human cellular reaponses to radiation depending on their irradiation in 2D monolayer vs 3D organized acinar growth conditions. We exmined cell reproductive death, chromosomal aberration induction, and the levels of γ-H2AX foci in cells after single acute gamma-ray doses and immediately after 20 hours of irradiation at a dose rate of 0.0017 Gy/min. We found no significant differences in the dose-responses of these cells under the 2D or 3D growth conditions. While this does not mean such differences cannot occur in other situations, it does mean that they do not generally or necessarily occur. In another series of studies in collaboration with Dr Chuan Li, with supprt from this current grant. We reported a role for apoptotic cell death in promoting wound healing and tissue regeneration in mice. Apoptotic cells released growth signals that stimulated the proliferation of progenitor or stem cells. In yet another collaboration with Dr, B. Chen with funds from this grant, the relative radiosensitivity to cell killing as well as chromosomal instability of 13 DNA-PKcs site-directed mutant cell lines (defective at phosphorylation sites or kinase

  7. Effects of low dose radiation on tumor-bearing mice

    International Nuclear Information System (INIS)

    Feng Li; Hou Dianjun; Huang Shanying; Deng Daping; Wang Linchao; Cheng Yufeng

    2007-01-01

    Objective: To explore the effects of low-dose radiation on tumor-bearing mice and radiotherapy induced by low-dose radiation. Methods: Male Wistar mice were implanted with Walker-256 sarcoma cells in the right armpit. On day 4, the mice were given 75 mGy whole-body X-ray radiation. From the fifth day, tumor volume was measured, allowing for the creation of a graph depicting tumor growth. Lymphocytes activity in mice after whole-body X-ray radiation with LDR was determinned by FCM. Cytokines level were also determined by ELISA. Results: Compared with the radiotherapy group, tumor growth was significantly slower in the mice pre-exposed to low-dose radiation (P<0.05), after 15 days, the average tumor weight in the mice pre- exposed to low-dose radiation was also significantly lower (P<0.05). Lymphocytes activity and the expression of the CK in mice after whole-body y-ray radiation with LDR increased significantly. Conclusions: Low-dose radiation can markedly improve the immune function of the lymphocyte, inhibit the tumor growth, increase the resistant of the high-dose radiotherapy and enhance the effect of radiotherapy. (authors)

  8. Low Dose Vaporized Cannabis Significantly Improves Neuropathic Pain

    Science.gov (United States)

    Wilsey, Barth; Marcotte, Thomas D.; Deutsch, Reena; Gouaux, Ben; Sakai, Staci; Donaghe, Haylee

    2013-01-01

    We conducted a double-blind, placebo-controlled, crossover study evaluating the analgesic efficacy of vaporized cannabis in subjects, the majority of whom were experiencing neuropathic pain despite traditional treatment. Thirty-nine patients with central and peripheral neuropathic pain underwent a standardized procedure for inhaling either medium dose (3.53%), low dose (1.29%), or placebo cannabis with the primary outcome being VAS pain intensity. Psychoactive side-effects, and neuropsychological performance were also evaluated. Mixed effects regression models demonstrated an analgesic response to vaporized cannabis. There was no significant difference between the two active dose groups’ results (p>0.7). The number needed to treat (NNT) to achieve 30% pain reduction was 3.2 for placebo vs. low dose, 2.9 for placebo vs. medium dose, and 25 for medium vs. low dose. As these NNT are comparable to those of traditional neuropathic pain medications, cannabis has analgesic efficacy with the low dose being, for all intents and purposes, as effective a pain reliever as the medium dose. Psychoactive effects were minimal and well-tolerated, and neuropsychological effects were of limited duration and readily reversible within 1–2 hours. Vaporized cannabis, even at low doses, may present an effective option for patients with treatment-resistant neuropathic pain. PMID:23237736

  9. Low Dose Radiation Response Curves, Networks and Pathways in Human Lymphoblastoid Cells Exposed from 1 to 10 cGy of Acute Gamma Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Wyrobek, A. J.; Manohar, C. F.; Nelson, D. O.; Furtado, M. R.; Bhattacharya, M. S.; Marchetti, F.; Coleman, M.A.

    2011-04-18

    We investigated the low dose dependency of the transcriptional response of human cells to characterize the shape and biological functions associated with the dose response curve and to identify common and conserved functions of low dose expressed genes across cells and tissues. Human lymphoblastoid (HL) cells from two unrelated individuals were exposed to graded doses of radiation spanning the range of 1-10 cGy were analyzed by transcriptome profiling, qPCR and bioinformatics, in comparison to sham irradiated samples. A set of {approx}80 genes showed consistent responses in both cell lines; these genes were associated with homeostasis mechanisms (e.g., membrane signaling, molecule transport), subcellular locations (e.g., Golgi, and endoplasmic reticulum), and involved diverse signal transduction pathways. The majority of radiation-modulated genes had plateau-like responses across 1-10 cGy, some with suggestive evidence that transcription was modulated at doses below 1 cGy. MYC, FOS and TP53 were the major network nodes of the low-dose response in HL cells. Comparison our low dose expression findings in HL cells with those of prior studies in mouse brain after whole body exposure, in human keratinocyte cultures, and in endothelial cells cultures, indicates that certain components of the low dose radiation response are broadly conserved across cell types and tissues, independent of proliferation status.

  10. Risks to health from radiation at low dose rates

    International Nuclear Information System (INIS)

    Gentner, N.E.; Osborne, R.V.

    1997-01-01

    Our focus is on whether, using a balance-of-evidence approach, it is possible to say that at a low enough dose, or at a sufficiently low dose rate, radiation risk reduces to zero in a population. We conclude that insufficient evidence exists at present to support such a conclusion. In part this reflects statistical limitations at low doses, and in part (although mechanisms unquestionably exist to protect us against much of the damage induced by ionizing radiation) the biological heterogeneity of human populations, which means these mechanisms do not act in all members of the population at all times. If it is going to be possible to demonstrate that low doses are less dangerous than we presently assume, the evidence, paradoxically, will likely come from studies of higher dose and dose rate scenarios than are encountered occupationally. (author)

  11. Biological effects of low-dose ionizing radiation exposure

    International Nuclear Information System (INIS)

    Reinoehl-Kompa, Sabine; Baldauf, Daniela; Heller, Horst

    2009-01-01

    The report on the meeting of the Strahlenschutzkommission 2007 concerning biological effects of low-dose ionizing radiation exposure includes the following contributions: Adaptive response. The importance of DNA damage mechanisms for the biological efficiency of low-energy photons. Radiation effects in mammography: the relative biological radiation effects of low-energy photons. Radiation-induced cataracts. Carcinomas following prenatal radiation exposure. Intercellular apoptosis induction and low-dose irradiation: possible consequences for the oncogenesis control. Mechanistic models for the carcinogenesis with radiation-induced cell inactivation: application to all solid tumors in the Japanese atomic bomb survivors. Microarrays at low radiation doses. Mouse models for the analysis of biological effects of low-dose ionizing radiation. The bystander effect: observations, mechanisms and implications. Lung carcinoma risk of Majak workers - modeling of carcinogenesis and the bystander effect. Microbeam studies in radiation biology - an overview. Carcinogenesis models with radiation-induced genomic instability. Application to two epidemiological cohorts.

  12. Low doses of arsenic, via perturbing p53, promotes tumorigenesis

    Energy Technology Data Exchange (ETDEWEB)

    Ganapathy, Suthakar, E-mail: s.ganapathy@neu.edu [Center for Drug Development, Northeastern University, Boston (United States); Li, Ping [The First Affiliated Hospital, Zhengzhou University, Zhengzhou (China); The Institute of Clinic Sciences, Sahlgrenska Academy, Gothenburg (Sweden); Fagman, Johan [The Institute of Clinic Sciences, Sahlgrenska Academy, Gothenburg (Sweden); Yu, Tianqi; Lafontant, Jean [Center for Drug Development, Northeastern University, Boston (United States); Zhang, Guojun [The First Affiliated Hospital, Zhengzhou University, Zhengzhou (China); Chen, Changyan [Center for Drug Development, Northeastern University, Boston (United States); The Institute of Clinic Sciences, Sahlgrenska Academy, Gothenburg (Sweden)

    2016-09-01

    In drinking water and in workplace or living environments, low doses of arsenic can exist and operate as a potent carcinogen. Due to insufficient understanding and information on the pervasiveness of environmental exposures to arsenic, there is an urgent need to elucidate the underlying molecular mechanisms of arsenic regarding its carcinogenic effect on human health. In this study, we demonstrate that low doses of arsenic exposure mitigate or mask p53 function and further perturb intracellular redox state, which triggers persistent endoplasmic reticulum (ER) stress and activates UPR (unfolded protein response), leading to transformation or tumorigenesis. Thus, the results suggest that low doses of arsenic exposure, through attenuating p53-regulated tumor suppressive function, change the state of intracellular redox and create a microenvironment for tumorigenesis. Our study also provides the information for designing more effective strategies to prevent or treat human cancers initiated by arsenic exposure.

  13. Low doses of arsenic, via perturbing p53, promotes tumorigenesis

    International Nuclear Information System (INIS)

    Ganapathy, Suthakar; Li, Ping; Fagman, Johan; Yu, Tianqi; Lafontant, Jean; Zhang, Guojun; Chen, Changyan

    2016-01-01

    In drinking water and in workplace or living environments, low doses of arsenic can exist and operate as a potent carcinogen. Due to insufficient understanding and information on the pervasiveness of environmental exposures to arsenic, there is an urgent need to elucidate the underlying molecular mechanisms of arsenic regarding its carcinogenic effect on human health. In this study, we demonstrate that low doses of arsenic exposure mitigate or mask p53 function and further perturb intracellular redox state, which triggers persistent endoplasmic reticulum (ER) stress and activates UPR (unfolded protein response), leading to transformation or tumorigenesis. Thus, the results suggest that low doses of arsenic exposure, through attenuating p53-regulated tumor suppressive function, change the state of intracellular redox and create a microenvironment for tumorigenesis. Our study also provides the information for designing more effective strategies to prevent or treat human cancers initiated by arsenic exposure.

  14. Regulatory aspects of low doses control in Albania

    International Nuclear Information System (INIS)

    Dollani, K.; Kushe, R.

    1997-01-01

    In the present paper are described the status of regulatory aspects of low doses control as well as the existing procedures for their implementation in Albania. According to new Radiological Protection Act, approved by Parliament in 1995, the establishment of the infrastructures in radiation protection area is in course, accompanied by the installation and functioning of new equipment for low dose control. Based in many years experience it is concluded that personal doses of the workers added by practices in Albania are 1/10 of dose Emits. Some particular cases of overexposured workers were investigated. Last times the elements of the optimisation procedures (QA and QC) are outlined in the frame of improving regulatory aspects of low doses control. (author)

  15. Low-Dose Risk, Decisions, and Risk Communication

    International Nuclear Information System (INIS)

    Flynn, James; Slovic, Paul

    2001-01-01

    To conduct basic research on how people receive, evaluate, and form positions on scientific information and its relationship to low-dose radiation exposure. There are three major areas of study in our research program. First is the development of theories, frameworks and concepts essential to guiding data collection and analysis. The second area is a program of experimental studies on risk perception, evaluation of science information, and the structure of individual positions regarding low dose exposures. This involves the study of existing knowledge and the evaluation of science information presented within a variety of formats, as educational information, news media stories, and alternative communication methods (personal contact, small group interaction, email and internet, etc.). Third is the community-level studies to examine and record how the social conditions, under which science communications take place, influence the development of attitudes and opinions about: low- dose exposures, the available management options, control of radiation risks, and preferences for program and policy goals

  16. Effects of low dose radiation and epigenetic regulation

    International Nuclear Information System (INIS)

    Jiao Benzheng; Ma Shumei; Yi Heqing; Kong Dejuan; Zhao Guangtong; Gao Lin; Liu Xiaodong

    2010-01-01

    Purpose: To conclude the relationship between epigenetics regulation and radiation responses, especially in low-dose area. Methods: The literature was examined for papers related to the topics of DNA methylation, histone modifications, chromatin remodeling and non-coding RNA modulation in low-dose radiation responses. Results: DNA methylation and radiation can regulate reciprocally, especially in low-dose radiation responses. The relationship between histone methylation and radiation mainly exists in the high-dose radiation area; histone deacetylase (HDAC) inhibitors show a promising application to enhance radiation sensitivity, no matter whether in low-dose or high-dose areas; the connection between γ-H2AX and LDR has been remained unknown, although γ-H2AX has been shown no radiation sensitivities with 1-15 Gy irradiation; histone ubiquitination play an important role in DNA damage repair mechanism. Moreover, chromatin remodeling has an integral role in DSB repair and the chromatin response, in general, may be precede DNA end resection. Finally, the effect of radiation on miRNA expression seems to vary according to cell type, radiation dose, and post-irradiation time point. Conclusion: Although the advance of epigenetic regulation on radiation responses, which we are managing to elucidate in this review, has been concluded, there are many questions and blind blots deserved to investigated, especially in low-dose radiation area. However, as progress on epigenetics, we believe that many new elements will be identified in the low-dose radiation responses which may put new sights into the mechanisms of radiation responses and radiotherapy. (authors)

  17. Low-dose vaporized cannabis significantly improves neuropathic pain.

    Science.gov (United States)

    Wilsey, Barth; Marcotte, Thomas; Deutsch, Reena; Gouaux, Ben; Sakai, Staci; Donaghe, Haylee

    2013-02-01

    We conducted a double-blind, placebo-controlled, crossover study evaluating the analgesic efficacy of vaporized cannabis in subjects, the majority of whom were experiencing neuropathic pain despite traditional treatment. Thirty-nine patients with central and peripheral neuropathic pain underwent a standardized procedure for inhaling medium-dose (3.53%), low-dose (1.29%), or placebo cannabis with the primary outcome being visual analog scale pain intensity. Psychoactive side effects and neuropsychological performance were also evaluated. Mixed-effects regression models demonstrated an analgesic response to vaporized cannabis. There was no significant difference between the 2 active dose groups' results (P > .7). The number needed to treat (NNT) to achieve 30% pain reduction was 3.2 for placebo versus low-dose, 2.9 for placebo versus medium-dose, and 25 for medium- versus low-dose. As these NNTs are comparable to those of traditional neuropathic pain medications, cannabis has analgesic efficacy with the low dose being as effective a pain reliever as the medium dose. Psychoactive effects were minimal and well tolerated, and neuropsychological effects were of limited duration and readily reversible within 1 to 2 hours. Vaporized cannabis, even at low doses, may present an effective option for patients with treatment-resistant neuropathic pain. The analgesia obtained from a low dose of delta-9-tetrahydrocannabinol (1.29%) in patients, most of whom were experiencing neuropathic pain despite conventional treatments, is a clinically significant outcome. In general, the effect sizes on cognitive testing were consistent with this minimal dose. As a result, one might not anticipate a significant impact on daily functioning. Published by Elsevier Inc.

  18. The researches on the effects of low doses irradiation

    International Nuclear Information System (INIS)

    2009-02-01

    All research conducted as part of 'Risc-Rad' and those conducted by actors in international programs on low doses allow progress in understanding mechanisms of carcinogenesis associated with irradiation. The data do not question the use in radiation protection, risk estimation models based on a linear increase of the risk with the dose of radiation. Nevertheless, they show that the nature of biological responses induced by low doses of radiation has differences with the responses induced by high doses of radiation. They also show the diversity of effects/dose relationships as the mechanism observed and the importance of genetic predisposition in the individual sensitivity to low doses of radiation. It is therefore essential to continue to bring new data to better understand the complex biological effects and their impact on the establishment of radiation protection standards. In addition, the results have often been at the cellular level. The diversity of responses induced by radiations is also a function of cell types observed, the aging of cells and tissue organization. It is essential to strengthen researches at the tissue and body level, involving in vitro and in vivo approaches while testing the hypothesis in epidemiology with a global approach to systems biology. Over the past four years, the collaboration between partners of 'Risc-Rad' using experimental biology approaches and those using mathematical modeling techniques aimed at developing a new model describing the carcinogenesis induced by low radiation doses. On an other hand, The High level expert group on European low dose risk research (H.L.E.G.) develop programmes in the area of low dose irradiation (Germany, Finland, France, Italy and United Kingdom). It proposed a structure of trans national government called M.E.L.O.D.I. ( multidisciplinary european low dose initiative). Its objective is to structure and integrate European research by gathering around a common programme of multidisciplinary

  19. Some remarks on the significance of low doses

    International Nuclear Information System (INIS)

    Cigna, A.A.

    1989-12-01

    The criteria of the present system of individual dose limitation are considered as well as the evolution of the limiting values. The assumption of the linearity of the dose-effect relationship without any threshold is probably the best approach to adopt for recommendations in radiation protection and for accounting the doses acquired by exposure to ionizing radiation. On the other hand the present evaluation of the natural background could imply a different dose-effect relationship in the low doses region and perhaps the existence of a threshold. Therefore the extrapolations which are usually made after exposures of different groups of people to low doses cannot be considered as scientifically sound. (author)

  20. Mechanisms of Low Dose Radiation-induced T helper Cell Function

    International Nuclear Information System (INIS)

    Gridley, Daila S.

    2008-01-01

    Exposure to radiation above levels normally encountered on Earth can occur during wartime, accidents such as those at Three Mile Island and Chernobyl, and detonation of 'dirty bombs' by terrorists. Relatively high levels of radiation exposure can also occur in certain occupations (low-level waste sites, nuclear power plants, nuclear medicine facilities, airline industry, and space agencies). Depression or dysfunction of the highly radiosensitive cells of the immune system can lead to serious consequences, including increased risk for infections, cancer, hypersensitivity reactions, poor wound healing, and other pathologies. The focus of this research was on the T helper (Th) subset of lymphocytes that secrete cytokines (proteins), and thus control many actions and interactions of other cell types that make up what is collectively known as the immune system. The Department of Energy (DOE) Low Dose Radiation Program is concerned with mechanisms altered by exposure to high energy photons (x- and gamma-rays), protons and electrons. This study compared, for the first time, the low-dose effects of two of these radiation forms, photons and protons, on the response of Th cells, as well as other cell types with which they communicate. The research provided insights regarding gene expression patterns and capacity to secrete potent immunostimulatory and immunosuppressive cytokines, some of which are implicated in pathophysiological processes. Furthermore, the photon versus proton comparison was important not only to healthy individuals who may be exposed, but also to patients undergoing radiotherapy, since many medical centers in the United States, as well as worldwide, are now building proton accelerators. The overall hypothesis of this study was that whole-body exposure to low-dose photons (gamma-rays) will alter CD4+ Th cell function. We further proposed that exposure to low-dose proton radiation will induce a different pattern of gene and functional changes compared to

  1. Late effects of low-dose ionizing radiation on man

    International Nuclear Information System (INIS)

    Brilliant, M.D.; Vorob'ev, A.I.; Gogin, E.E.

    1987-01-01

    One of the most important problems, being stated before the medicine by the accident, which took place in Chernobyl in 1986- the problem of the so-called ionizing radiation low dose effect on a man's organism, is considered because a lot of people were subjected to low dose action. The concept of low doses of radiaion action and specificity of its immediate action in comparison with high dose action is considered. One of the most important poit while studying low dose action is the necessity to develop a system including all irradiated people and dosimetry, and espicially to study frequencies and periods of tumor appearance in different irradiated tissues. The results obtained when examining people who survived the atomic explosion in Japan and on the Marshall islands are analyzed. They testify to the fact that radiation affets more tissues than the clinical picture about the acute radiation sickness tells, and that tumors developing in them many years after radiation action tell about radiosensitivity in some tissues

  2. Use of combined paracetamol and low dose ketamine in pain ...

    African Journals Online (AJOL)

    Objective: To determine the effectiveness of Paracetamol and low dose Ketamine in controlling burn pain during dressings. Setting: The burns ward of Moi Teaching and Referral Hospital, a 750 bed capacity tertiary centre in Western Kenya. Subjects: Consenting patients were recruited to the study on admission. Babies and ...

  3. Low-dose aspirin and risk of intracranial bleeds

    DEFF Research Database (Denmark)

    Cea Soriano, Lucía; Gaist, David; Soriano-Gabarró, Montse

    2017-01-01

    cohort of nonusers of low-dose aspirin at baseline were followed (maximum 14 years, median 5.4 years) to identify incident cases of ICB, with validation by manual review of patient records or linkage to hospitalization data. Using 10,000 frequency-matched controls, adjusted rate ratios (RRs) with 95...

  4. Biological effects of very low doses of ionizing radiation

    International Nuclear Information System (INIS)

    Evseev, V.S.

    1987-01-01

    The paper deals with a qualitative microdosimetric analysis of a new radiobiological phenomenon (physiological reaction of the cell as a whole to very low doses of ionizing radiations). The analysis is aimed at identifying the type of the primary interaction of radiation with the cell and finding its place in the cell

  5. Advance of study on hormesis of low dose radiation

    International Nuclear Information System (INIS)

    Su Liaoyuan

    2003-01-01

    There have been growing interests in recent years over the effects of low doses of ionizing radiation on human. The paper gives a brief review on the LDR studies, which include LDR-induced hormesis and adaptive response, LDR experiments in vivo or in vitro and epidemiologic investigation, and clinical applications of LDR as well

  6. Low dose CT simulation using experimental noise model

    Energy Technology Data Exchange (ETDEWEB)

    Nakanishi, Satori; Zamyatin, Alexander A. [Toshiba Medical Systems Corporation, Tochigi, Otawarashi (Japan); Silver, Michael D. [Toshiba Medical Research Institute, Vernon Hills, IL (United States)

    2011-07-01

    We suggest a method to obtain system noise model experimentally without relying on assumptions on statistical distribution of the noise; also, knowledge of DAS gain and electronic noise level are not required. Evaluation with ultra-low dose CT data (5 mAs) shows good match between simulated and real data noise. (orig.)

  7. CARCINOGENIC EFFECTS OF LOW DOSES OF IONIZING RADIATION

    Science.gov (United States)

    Carcinogenic Effects of Low Doses of Ionizing RadiationR Julian Preston, Environmental Carcinogenesis Division, NHEERL, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711The form of the dose-response curve for radiation-induced cancers, particu...

  8. Malignant melanoma of the tongue following low-dose radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kalemeris, G.C.; Rosenfeld, L.; Gray, G.F. Jr.; Glick, A.D.

    1985-03-01

    A 47-year-old man had a spindly malignant melanoma of the tongue many years after low-dose radiation therapy for lichen planus. To our knowledge, only 12 melanomas of the tongue have been reported previously, and in none of these was radiation documented.

  9. Malignant melanoma of the tongue following low-dose radiation

    International Nuclear Information System (INIS)

    Kalemeris, G.C.; Rosenfeld, L.; Gray, G.F. Jr.; Glick, A.D.

    1985-01-01

    A 47-year-old man had a spindly malignant melanoma of the tongue many years after low-dose radiation therapy for lichen planus. To our knowledge, only 12 melanomas of the tongue have been reported previously, and in none of these was radiation documented

  10. Topics on study of low dose-effect relationship

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Takeshi [Toho Univ., School of Medicine, Tokyo (Japan); Ohyama, Harumi

    1999-09-01

    It is not exceptional but usually observed that a dose-effect relationship in biosystem is not linear. Sometimes, the low dose-effect relationship appears entirely contrary to the expectation from high dose-effect. This is called a 'hormesis' phenomena. A high dose irradiation inflicts certainly an injury on biosystem. No matter how low the dose may be, an irradiation might inflict some injury on biosystem according to Linear Non-Threshold hypothesis(LNT). On the contrary to the expectation, a low dose irradiation stimulates immune system, and promotes cell proliferation. This is called 'radiation hormesis'. The studies of the radiation hormesis are made on from four points of view as follows: (1) radiation adaptive response, (2) revitalization caused by a low dose stimulation, (3) a low dose response unexpected from the LNT hypothesis, (4) negation of the LNT hypothesis. The various empirical proofs of radiation hormesis are introduced in the report. (M . Suetake)

  11. Health hazards of low doses of ionizing radiations. Vo. 1

    International Nuclear Information System (INIS)

    El-Naggar, M.A.

    1996-01-01

    Exposure to high doses of ionizing radiation results in clinical manifestations of several disease entities that may be fatal. The onset and severity of these acute radiation syndromes are deterministic in relation to dose magnitude. Exposure to ionizing radiations at low doses and low dose rates could initiate certain damage in critical molecules of the cell, that may develop in time into serious health effects. The incidence of such delayed effects in low, and is only detectable through sophisticated epidemiological models carried out on large populations. The radiation damage induced in critical molecules of cells may develop by stochastic biochemical mechanisms of repair, residual damage, adaptive response, cellular transformation, promotion and progression into delayed health effects, the most important of which is carcinogenesis. The dose response relationship of probabilistic stochastic delayed effects of radiation at low doses and low dose rates, is very complex indeed. The purpose of this review is to provide a comprehensive understanding of the underlying mechanisms, the factors involved, and the uncertainties encountered. Contrary to acute deterministic effects, the occurrence of probabilistic delayed effects of radiation remains to be enigmatic. 7 figs

  12. Mechanisms of Low Dose Radio-Suppression of Genomic Instability

    Energy Technology Data Exchange (ETDEWEB)

    Engelward, Bevin P. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2009-09-16

    The major goal of this project is to contribute toward the elucidation of the impact of long term low dose radiation on genomic stability. We have created and characterized novel technologies for delivering long term low dose radiation to animals, and we have studied genomic stability by applying cutting edge molecular analysis technologies. Remarkably, we have found that a dose rate that is 300X higher than background radiation does not lead to any detectable genomic damage, nor is there any significant change in gene expression for genes pertinent to the DNA damage response. These results point to the critical importance of dose rate, rather than just total dose, when evaluating public health risks and when creating regulatory guidelines. In addition to these studies, we have also further developed a mouse model for quantifying cells that have undergone a large scale DNA sequence rearrangement via homologous recombination, and we have applied these mice in studies of both low dose radiation and space radiation. In addition to more traditional approaches for assessing genomic stability, we have also explored radiation and possible beneficial effects (adaptive response), long term effects (persistent effects) and effects on communication among cells (bystander effects), both in vitro and in vivo. In terms of the adaptive response, we have not observed any significant induction of an adaptive response following long term low dose radiation in vivo, delivered at 300X background. In terms of persistent and bystander effects, we have revealed evidence of a bystander effect in vivo and with researchers at and demonstrated for the first time the molecular mechanism by which cells “remember” radiation exposure. Understanding the underlying molecular mechanisms by which radiation can induce genomic instability is fundamental to our ability to assess the biological impact of low dose radiation. Finally, in a parallel set of studies we have explored the effects of heavy

  13. Personal dosimetry statistics and specifics of low dose evaluation

    International Nuclear Information System (INIS)

    Avila, R.E.; Gómez Salinas, R.A.; Oyarzún Cortés, C.H.

    2015-01-01

    The dose statistics of a personal dosimetry service, considering 35,000+ readings, display a sharp peak at low dose (below 0.5 mSv) with skewness to higher values. A measure of the dispersion is that approximately 65% of the doses fall below the average plus 2 standard deviations, an observation which may prove helpful to radiation protection agencies. Categorizing the doses by the concomitant use of a finger ring dosimeter, that skewness is larger in the whole body, and ring dosimeters. The use of Harshaw 5500 readers at high gain leads to frequent values of the glow curve that are judged to be spurious, i.e. values not belonging to the roughly normal noise over the curve. A statistical criterion is shown for identifying those anomalous values, and replacing them with the local behavior, as fit by a cubic polynomial. As a result, the doses above 0.05 mSv which are affected by more than 2% comprise over 10% of the data base. The low dose peak of the statistics, above, has focused our attention on the evaluation of LiF(Mg,Ti) dosimeters exposed at low dose, and read with Harshaw 5500 readers. The standard linear procedure, via an overall reader calibration factor, is observed to fail at low dose, in detailed calibrations from 0.02 mSv to 1 Sv. A significant improvement is achieved by a piecewise polynomials calibration curve. A cubic, at low dose is matched, at ∼10 mSv, in value and first derivative, to a linear dependence at higher doses. This improvement is particularly noticeable below 2 mSv, where over 60% of the evaluated dosimeters are found. (author)

  14. Comparison of hyperuricemia in type 2 diabetics on low dose aspirin and not on low dose aspirin

    International Nuclear Information System (INIS)

    Malik, M.I.

    2013-01-01

    Objective: To compare the frequency of hyperuricemia in type 2 diabetes patients who are taking low dose aspirin with those patients who are not taking low dose aspirin. Study design: Quasi experimental study. Place and duration of study: This study was carried out at Military Hospital Rawalpindi for a period of two years (June 2006-May 2008). Patients and Methods: Sixty diabetic patients were selected who were taking low dose aspirin comparing group A and sixty diabetic patients who were not taking aspirin were placed in group B. These patients were selected from the OPD through non probability convenience sampling. All these patients were being followed up in medical outpatient quite regularly on fort-nightly basis. Data had been collected through a carefully designed questionnaire. Results: In group A, 90% of the patients had uric acid less than 445 micro mol/l and 10% of the patients had uric acid more than 445micro mol/l. Whereas in group B 100% of the patients had uric acid less than 445umol/l, there was a statistically significant difference between the two groups (p< 0.05). Conclusion: Aspirin in low doses cause hyperuricemia and regular monitoring of uric acid is mandatory to prevent its adverse effects. (author)

  15. A Paradigm Shift in Low Dose Radiation Biology

    Directory of Open Access Journals (Sweden)

    Z. Alatas

    2015-08-01

    Full Text Available When ionizing radiation traverses biological material, some energy depositions occur and ionize directly deoxyribonucleic acid (DNA molecules, the critical target. A classical paradigm in radiobiology is that the deposition of energy in the cell nucleus and the resulting damage to DNA are responsible for the detrimental biological effects of radiation. It is presumed that no radiation effect would be expected in cells that receive no direct radiation exposure through nucleus. The risks of exposure to low dose ionizing radiation are estimated by extrapolating from data obtained after exposure to high dose radiation. However, the validity of using this dose-response model is controversial because evidence accumulated over the past decade has indicated that living organisms, including humans, respond differently to low dose radiation than they do to high dose radiation. Moreover, recent experimental evidences from many laboratories reveal the fact that radiation effects also occur in cells that were not exposed to radiation and in the progeny of irradiated cells at delayed times after radiation exposure where cells do not encounter direct DNA damage. Recently, the classical paradigm in radiobiology has been shifted from the nucleus, specifically the DNA, as the principal target for the biological effects of radiation to cells. The universality of target theory has been challenged by phenomena of radiation-induced genomic instability, bystander effect and adaptive response. The new radiation biology paradigm would cover both targeted and non-targeted effects of ionizing radiation. The mechanisms underlying these responses involve biochemical/molecular signals that respond to targeted and non-targeted events. These results brought in understanding that the biological response to low dose radiation at tissue or organism level is a complex process of integrated response of cellular targets as well as extra-cellular factors. Biological understanding of

  16. Addition of low-dose ketamine to midazolam and low-dose bupivacaine improves hemodynamics and postoperative analgesia during spinal anesthesia for cesarean section

    Directory of Open Access Journals (Sweden)

    Ahmed Sobhy Basuni

    2016-01-01

    Conclusion: Intrathecal low-dose ketamine combined with midazolam and low-dose bupivacaine stabilizes hemodynamics and prolongs postoperative analgesia without significant side-effects in parturients undergoing CS.

  17. Repair and dose-response at low doses

    International Nuclear Information System (INIS)

    Totter, J.R.; Weinberg, A.M.

    1977-04-01

    The DNA of each individual is subject to formation of some 2-4 x 10 14 ion pairs during the first 30 years of life from background radiation. If a single hit is sufficient to cause cancer, as is implicit in the linear, no-threshold theories, it is unclear why all individuals do not succumb to cancer, unless repair mechanisms operate to remove the damage. We describe a simple model in which the exposed population displays a distribution of repair thresholds. The dose-response at low dose is shown to depend on the shape of the threshold distribution at low thresholds. If the probability of zero threshold is zero, the response at low dose is quadratic. The model is used to resolve a longstanding discrepancy between observed incidence of leukemia at Nagasaki and the predictions of the usual linear hypothesis

  18. Response of human fibroblasts to low dose rate gamma irradiation

    International Nuclear Information System (INIS)

    Dritschilo, A.; Brennan, T.; Weichselbaum, R.R.; Mossman, K.L.

    1984-01-01

    Cells from 11 human strains, including fibroblasts from patients with the genetic diseases of ataxia telangiectasia (AT), xeroderma pigmentosum (XP), and Fanconi's anemia (FA), were exposed to γ radiation at high (1.6-2.2 Gy/min) and at low (0.03-0.07 Gy/min) dose rates. Survival curves reveal an increase inthe terminal slope (D 0 ) when cells are irradiated at low dose rates compared to high dose rates. This was true for all cell lines tested, although the AT, FA, and XP cells are reported or postulated to have radiation repair deficiencies. From the response of these cells, it is apparent that radiation sensitivities differ; however, at low dose rate, all tested human cells are able to repair injury

  19. Low dose CT in early lung cancer diagnosis: prevalence data

    International Nuclear Information System (INIS)

    Cardinale, Luciano; Cortese, Giancarlo; Ferraris, Fabrizio; Perotto, Fabio; Fava, Cesare; Borasio, Piero; Dogliotti, Luigi; Novello, Silvia; Scagliotti, Giorgio

    2005-01-01

    Purpose. Lung cancer has a high mortality rate and its prognosis largely depends on early detection. We report the prevalence data of the study on early detection of lung cancer with low-dose spiral CT underway at our hospital. Materials and methods. Since the beginning of 2001, 519 asymptomatic volunteers have undergone annual blood tests, sputum tests, urinalyses and low-dose spiral CT. The inclusion criteria were age (55 years old), a history of cigarette smoking and a negative history for previous neoplastic disease. The diagnostic workup varied depending on the size and CT features of the nodules detected. Results. At baseline, the CT scan detected nodules> 5 mm in 22% of subjects; the nodules were single in 42 and multiple in 71. In 53% of cases the findings were completely negative, while in 122 (23.4%) nodules with a diameter [it

  20. Low-Dose Aspirin for the Prevention of Preeclampsia.

    Science.gov (United States)

    Fantasia, Heidi Collins

    2018-02-01

    Preeclampsia is a hypertensive disorder specific to pregnancy that remains a significant cause of maternal and neonatal morbidity and mortality. Identification of women who are most at risk for preeclampsia is imprecise. Because of the potential negative health consequences of preeclampsia for women and newborns and the lack of effective screening mechanisms preventing preeclampsia is an important component of prenatal care. Researchers have documented that low-dose aspirin, taken daily after the first trimester, can decrease the development of preeclampsia and reduce the incidence of preterm birth and birth of small-for-gestational-age infants. This column includes an overview of low-dose aspirin in pregnancy and a review of current recommendations from leading national organizations. © 2018 AWHONN, the Association of Women’s Health, Obstetric and Neonatal Nurses.

  1. The assessment of the carcinogenic effects of low dose radiation

    International Nuclear Information System (INIS)

    Tubiana, M.; Lafuma, J.; Masse, R.; Latarjet, R.

    1991-01-01

    It is concluded that the exclusion of patients for the purposes of risk estimation, the choice of a particular relative risk projection model and of a dose reduction factor equal to 2 are all decisions which result in an overestimation of the actual risk. These choices can be understood when the aim is radiation protection and when it is safer to overestimate the risk; however, they are open to criticism if the aim is a realistic assessment of the risk. For low doses, below 50 mSv/year, and when all causes of uncertainty are added, the actual risk might be markedly lower than the risk estimated with the ICRP (1991) carcinogenic risk coefficient and the DRF estimated by ICRP. Future studies should aim at providing direct and more precise assessments of risk coefficients in the low dose region. (Author)

  2. Gamma regularization based reconstruction for low dose CT

    International Nuclear Information System (INIS)

    Zhang, Junfeng; Chen, Yang; Hu, Yining; Luo, Limin; Shu, Huazhong; Li, Bicao; Liu, Jin; Coatrieux, Jean-Louis

    2015-01-01

    Reducing the radiation in computerized tomography is today a major concern in radiology. Low dose computerized tomography (LDCT) offers a sound way to deal with this problem. However, more severe noise in the reconstructed CT images is observed under low dose scan protocols (e.g. lowered tube current or voltage values). In this paper we propose a Gamma regularization based algorithm for LDCT image reconstruction. This solution is flexible and provides a good balance between the regularizations based on l 0 -norm and l 1 -norm. We evaluate the proposed approach using the projection data from simulated phantoms and scanned Catphan phantoms. Qualitative and quantitative results show that the Gamma regularization based reconstruction can perform better in both edge-preserving and noise suppression when compared with other norms. (paper)

  3. Low-dose effects hypothesis and observations on NPP personal

    Energy Technology Data Exchange (ETDEWEB)

    Georgieva, R.; Acheva, A.; Boteva, R.; Chobanova, N.; Djounova, J.; Gyuleva, I.; Ivanova, K.; Kurchatova, G.; Milchev, A.; Negoicheva, K.; Nikolov, V.; Panova, D.; Pejankov, I.; Rupova, I.; Stankova, K.; Zacharieva, E. [Radiobiology Department, National Centre of Radiobiology and Radiation Protection, Sofia (Bulgaria)

    2013-07-01

    In the modern world the use of various sources of ionizing radiation is nearly ubiquitous. They have numerous applications in industry, medicine, science, agriculture, etc. Radiation doses to workers nevertheless are commensurable to the natural background exposure. Published data on the health effects of occupational radiation exposure are often contradictory. Addressing the issue of „negative” (bystander effects, genomic instability) and „positive” (adaptive response, radiation hormesis) effects of low doses is important and has a significant social and economic impact. In this paper we summarize the results of our extensive monitoring of nuclear power plant (NPP) staff. We believe it is a cohort suitable for analysis of health effects at low doses, because of their good medical and dosimetric control. Our results rather support the idea of absence of adverse health effects in NPP workers. (author)

  4. Effect of low-dose radiation on ocular circulation

    International Nuclear Information System (INIS)

    Baba, Keiko; Hiroishi, Goro; Honda, Masae; Yoshikawa, Hiroshi; Fujisawa, Kimihiko; Ishibashi, Tatsuro

    1999-01-01

    We treated 6 eyes of unilateral age-related macular degeneration by low-dose radiation. Each eye received daily dose of 2 Gy by 4MV lineac totalling 20 Gy over 2 weeks. Color doppler flowmetry was used to determine the mean blood flow velocity (Vmean) and vascular resistive index (RI) in the short posterior ciliary artery, central retinal artery and ophthalmic artery in the treated and fellow eyes before and up to 6 months of treatment. There were no significant differences in Vmean and RI before and after treatment. The findings show the absence of apparent influence of low-dose radiation on the ocular circulation in age-related macular degeneration. (author)

  5. Cystoid Macular Edema Induced by Low Doses of Nicotinic Acid

    Directory of Open Access Journals (Sweden)

    Daniela Domanico

    2013-01-01

    Full Text Available Cystoid macular edema (CME is a condition that involves the macula, causing painless vision loss. In this paper, we report a case of niacin-induced bilateral cystoid macular edema (CME in a middle-age woman taking low dose of niacin (18 mg of nicotinic acid. Optical coherence tomography (OCT showed retinal thickening and cystoid spaces in both eyes, whereas fluorescein angiography (FA; HRA 2, Heidelberg Engineering revealed the absence of fluorescein leakage also in later phases. Four weeks after discontinuation of therapy there were a complete disappearance of macular edema at funduscopic examination and an improvement of visual acuity in both eyes. Furthermore OCT showed a normal retinal profile in both eyes. In our opinion considering the wide availability of niacin, medical monitoring and periodical examination should be considered during niacin administration. To our knowledge, this is the first report in the literature that described the very low-dose niacin-induced bilateral niacin maculopathy.

  6. Effect of low-dose radiation on ocular circulation

    Energy Technology Data Exchange (ETDEWEB)

    Baba, Keiko; Hiroishi, Goro; Honda, Masae; Yoshikawa, Hiroshi; Fujisawa, Kimihiko; Ishibashi, Tatsuro [Kyushu Univ., Fukuoka (Japan). Faculty of Medicine

    1999-05-01

    We treated 6 eyes of unilateral age-related macular degeneration by low-dose radiation. Each eye received daily dose of 2 Gy by 4MV lineac totalling 20 Gy over 2 weeks. Color doppler flowmetry was used to determine the mean blood flow velocity (Vmean) and vascular resistive index (RI) in the short posterior ciliary artery, central retinal artery and ophthalmic artery in the treated and fellow eyes before and up to 6 months of treatment. There were no significant differences in Vmean and RI before and after treatment. The findings show the absence of apparent influence of low-dose radiation on the ocular circulation in age-related macular degeneration. (author)

  7. Low-dose radiation-induced endothelial cell retraction

    International Nuclear Information System (INIS)

    Kantak, S.S.; Onoda, J.M.; Diglio, C.A.; Harper Hospital, Detroit, MI

    1993-01-01

    The data presented here are representative of a series of studies designed to characterize low-dose radiation effects on pulmonary microvascular endothelium. Data suggest that post-irradiation lung injuries (e.g. oedema) may be induced with only a single fraction of therapeutic radiation, and thus microscopic oedema may initiate prior to the lethal effects of radiation on the microvascular endothelium, and much earlier than would be suggested by the time course for clinically-detectable oedema. (author)

  8. Late effects of low doses and dose rates

    International Nuclear Information System (INIS)

    Paretzke, H.G.

    1980-01-01

    This paper outlines the spectrum of problems and approaches used in work on the derivation of quantitative prognoses of late effects in man of low doses and dose rates. The origins of principal problems encountered in radiation risks assessments, definitions and explanations of useful quantities, methods of deriving risk factors from biological and epidemiological data, and concepts of risk evaluation and problems of acceptance are individually discussed

  9. Effects of low doses; Effet des faibles doses

    Energy Technology Data Exchange (ETDEWEB)

    Le Guen, B. [Electricite de France (EDF-LAM-SCAST), 93 - Saint-Denis (France)

    2001-07-01

    Actually, even though it is comfortable for the risk management, the hypothesis of the dose-effect relationship linearity is not confirmed for any model. In particular, in the area of low dose rate delivered by low let emitters. this hypothesis is debated at the light of recent observations, notably these ones relative to the mechanisms leading to genetic instability and induction eventuality of DNA repair. The problem of strong let emitters is still to solve. (N.C.)

  10. Fruit-flies in low-dose exposure experiments

    International Nuclear Information System (INIS)

    Zajnullin, V.G.; Moskalev, A.A.; Shaposhnikov, M.V.; Sheptyakova, A.I.

    2002-01-01

    In vivo exposure of fruit-flies of Drosophila melanogaster line to low doses provided new data indicating that mechanisms of induced genetic instability are involved in radiation-induced alteration of genotype. It is true for increase of genetic variance due to change in transposition number, for change in adaptation capabilities due to modification of gene expression, and for mutability-associated reparation and apoptosis. (author)

  11. Transportable, Low-Dose Active Fast-Neutron Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Mihalczo, John T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wright, Michael C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); McConchie, Seth M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Archer, Daniel E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Palles, Blake A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-08-01

    This document contains a description of the method of transportable, low-dose active fast-neutron imaging as developed by ORNL. The discussion begins with the technique and instrumentation and continues with the image reconstruction and analysis. The analysis discussion includes an example of how a gap smaller than the neutron production spot size and detector size can be detected and characterized depending upon the measurement time.

  12. Biological effects of low doses of ionising radiation

    International Nuclear Information System (INIS)

    Osmak, M.

    1998-01-01

    A study was performed with the aim to examine whether the progeny of cells that had been repeatedly irradiated with low doses of gamma rays will change their sensitivity to cytotoxic agents. Four mammalian cell lines were used in the experiment. It was found that the progeny of cells irradiated in this way do not change their sensitivity to gamma rays but would change their sensitivity to various cytostatics drugs. (A.K.)

  13. Effect of low dose ionizing radiation upon concentration of

    International Nuclear Information System (INIS)

    Viliae, M.; Kraljeviae, P.; Simpraga, M.; Miljaniae, S.

    2004-01-01

    It is known that low dose ionizing radiation might have stimulating effects (Luckey, 1982, Kraljeviae, 1988). This fact has also been confirmed in the previous papers of Kraljeviae et al. (2000-2000a; 2001). Namely, those authors showed that irradiation of chicken eggs before incubation by a low dose of 0.15 Gy gamma radiation increases the activity aspartateaminotrasferases (AST) and alanine-aminotransferases (ALT) in blood plasma of chickens hatched from irradiated eggs, as well as growth of chickens during the fattening period. Low doses might also cause changes in the concentration of some biochemical parameters in blood plasma of the same chickens such as changes in the concentration of total proteins, glucose and cholesterol. In this paper, an attempt was made to investigate the effects of low dose gamma radiation upon the concentration of sodium and potassium in the blood plasma of chickens which were hatched from eggs irradiated on the 19th day of incubation by dose of 0.15 Gy. Obtained results were compared with the results from the control group (chickens hatched from nonirradiated eggs). After hatching, all other conditions were the same for both groups. Blood samples were drawn from heart, and later from the wing vein on days 1, 3, 5, 7, 10, 20, 30 and 42. The concentration of sodium and potassium was determined spectrophotometrically by atomic absorbing spectrophotometer Perkin-Elmer 1100B. The concentration of sodium and potassium in blood plasma of chickens hatched from eggs irradiated on the 19th day of incubation by dose of 0.15 Gy indicated a statistically significant increase (P>0.01) only on the first day of the experiment. Obtained results showed that irradiation of eggs on the 19th day of incubation by dose of 0.15 Gy gamma radiation could have effects upon the metabolism of electrolytes in chickens. (Author)

  14. Low dose monitoring by double implant technique in IC fabrication

    International Nuclear Information System (INIS)

    Ahmad, I.B.; Weidemann, J.

    1995-01-01

    The utilisation of low dose implant monitoring (using Boron) in a manufacturing line has been discussed. The utilisation of phosphorus ions as the second implant dose were also studied as comparison. The technique relies on the fact that the sheet resistant of doped layer will increase significantly when damaged by relatively low implant dose. The technique is very sensitive and applicable for adjusting the channel dose so that an accurate threshold voltage in MOS device could be achieved

  15. adverse effects of low dose methotrexate in rheumatoid arthritis patients

    International Nuclear Information System (INIS)

    Gilani, S.T.; Khan, D.A.; Khan, F.A.; Ahmed, M.

    2012-01-01

    To determine the frequency of adverse effects attributed to Methotrexate (MTX) toxicity and serum minimum toxic concentration with low dose MTX in Rheumatoid Arthritis (RA) patients. Study Design: Cross-sectional observational study. Place and Duration of Study: Department of Chemical Pathology and Endocrinology, Armed Forces Institute of Pathology, Rawalpindi, from March 2010 to March 2011. Methodology: One hundred and forty adult patients of RA receiving low dose MTX (10 mg/week) for at least 3 months, ere included by consecutive sampling. Blood samples were collected 2 hours after the oral dose of MTX. Serum alanine transaminase and creatinine were analyzed on Hitachi and blood counts on Sysmex analyzer. Serum MTX concentration was measured on TDX analyzer. Results: Out of one hundred and forty patients; 68 males (49%) and 72 females (51%), 38 developed MTX toxicity (27%), comprising of hepatotoxicity in 12 (8.6%), nephrotoxicity in 3 (2.1%), anaemia in 8 (5.7%), leucopenia in 2 (1.4%), thrombocytopenia in 3 (2.1%), pancytopenia in 2 (1.4%), gastrointestinal adverse effects in 5 (3.6%) and mucocutaneous problems in 3 (2.1%). Receiver operating characteristic curve revealed serum minimum toxic concentration of MTX at cutoff value of 0.71 mu mol/l with a sensitivity of 71% and specificity of 76%. Conclusion: Adverse effects of low dose MTX were found in 27% of RA patients, mainly comprising of hepatotoxicity and haematological problems. MTX toxicity can be detected by therapeutic drug monitoring of serum concentration of 0.71 mu mol/l with sensitivity of 71% and specificity of 76% in the patients on low dose MTX maintenance therapy. (author)

  16. Global DNA methylation responses to low dose radiation exposure

    International Nuclear Information System (INIS)

    Newman, M.R.; Ormsby, R.J.; Blyth, B.J.; Sykes, P.J.; Bezak, E.

    2011-01-01

    Full text: High radiation doses cause breaks in the DNA which are considered the critical lesions in initiation of radiation-induced cancer. However, at very low radiation doses relevant for the general public, the induction of such breaks will be rare, and other changes to the DNA such as DNA methylation which affects gene expression may playa role in radiation responses. We are studying global DNA methylation after low dose radiation exposure to determine if low dose radiation has short- and/or long-term effects on chromatin structure. We developed a sensitive high resolution melt assay to measure the levels of DNA methylation across the mouse genome by analysing a stretch of DNA sequence within Long Interspersed Nuclear Elements-I (LINE I) that comprise a very large proportion of the mouse and human genomes. Our initial results suggest no significant short-term or longterm) changes in global NA methylation after low dose whole-body X-radiation of 10 J1Gyor 10 mGy, with a significant transient increase in NA methylation observed I day after a high dose of I Gy. If the low radiation doses tested are inducing changes in bal DNA methylation, these would appear to be smaller than the variation observed between the sexes and following the general stress of the sham-irradiation procedure itself. This research was funded by the Low Dose Radiation Research Program, Biological and Environmental Research, US DOE, Grant DE-FG02-05ER64104 and MN is the recipient of the FMCF/BHP Dose Radiation Research Scholarship.

  17. Exercise and Sport Performance with Low Doses of Caffeine

    OpenAIRE

    Spriet, Lawrence L.

    2014-01-01

    Caffeine is a popular work-enhancing supplement that has been actively researched since the 1970s. The majority of research has examined the effects of moderate to high caffeine doses (5–13 mg/kg body mass) on exercise and sport. These caffeine doses have profound effects on the responses to exercise at the whole-body level and are associated with variable results and some undesirable side effects. Low doses of caffeine (

  18. MELODI: The 'Multidisciplinary European Low-Dose Initiative'

    International Nuclear Information System (INIS)

    Belli, M.; Salomaa, S.; Ottolenghi, A.

    2011-01-01

    The importance of research to reduce uncertainties in risk assessment of low and protracted exposures is now recognised globally. In Europe a new initiative, called 'Multidisciplinary European Low Dose Initiative' (MELODI), has been proposed by a 'European High Level and Expert Group on low-dose risk research' (www.hleg.de), aimed at integrating national and EC (Euratom) efforts. Five national organisations: BfS (DE), CEA (FR), IRSN (FR), ISS (IT) and STUK (FI), with the support of the EC, have initiated the creation of MELODI by signing a letter of intent. In the forthcoming years, MELODI will integrate in a step-by-step approach EU institutions with significant programmes in the field and will be open to other scientific organisations and stakeholders. A key role of MELODI is to develop and maintain over time a strategic research agenda (SRA) and a road map of scientific priorities within a multidisciplinary approach, and to transfer the results for the radiation protection system. Under the coordination of STUK a network has been proposed in the 2009 Euratom Programme, called DoReMi (Low-Dose Research towards Multidisciplinary Integration), which can help the integration process within the MELODI platform. DoReMi and the First MELODI Open Workshop, organised by BfS in September 2009, are now important inputs for the European SRA. (authors)

  19. Low dose effects detected by micronucleus assay in lymphocytes

    International Nuclear Information System (INIS)

    Koeteles, G.J.; Bojtor, I.; Kubasova, T.; Horvath, G.

    1997-01-01

    The effects of low doses of X-rays between 0.01 and 1 Gy were studied on whole blood samples of various individuals using the cytokinesis-blocked lymphocyte micronucleus assay as an endpoint. The adaptive response could be induced in G 0 cells by 0.01 Gy followed by 1 Gy challenging dose within a time period of 8 hours, in vitro. The probability distribution of micronucleus increments in those samples which had received very low doses in the range 0.01-0.05 Gy proved to be of asymmetrical type (i.e. lognormal) -very likely to the same shape which has been verified for unirradiated (control) population - while the variable turned to be normally distributed at or above 1 Gy. Profound changes have been experienced in the main characteristics of the linear dose - response relationship and in regression parameters, as well, when successively lessened dose ranges were studied toward 0.01 Gy. In the range below ∼ 0.2 Gy the response were found to be unrelated to the absorbed dose. These findings suggest that in (very) low dose range a higher attention should be needed to biological parameters like repair, protective mechanisms and antioxidant capacities, rather than to the absorbed radiation energy only. (author)

  20. Problems linked to effects of ionizing radiations low doses

    International Nuclear Information System (INIS)

    Anon.

    1995-10-01

    The question of exposure to ionizing radiations low doses and risks existing for professional and populations has been asked again, with the recommendations of the International Commission of Radiation Protection (ICRP) to lower the previous standards and agreed as guides to organize radiation protection, by concerned countries and big international organisms. The sciences academy presents an analysis which concerned on epidemiological and dosimetric aspects in risk estimation, on cellular and molecular aspects of response mechanism to irradiation. The observation of absence of carcinogen effects for doses inferior to 200 milli-sieverts and a re-evaluation of data coming from Nagasaki and Hiroshima, lead to revise the methodology of studies to pursue, to appreciate more exactly the effects of low doses, in taking in part, particularly, the dose rate. The progress of molecular and cellular biology showed that the extrapolation from high doses to low doses is not in accordance with actual data. The acknowledge of DNA repair and carcinogenesis should make clearer the debate. (N.C.). 61 refs., 9 annexes

  1. Thermoluminescent dosimeters for low dose X-ray measurements

    International Nuclear Information System (INIS)

    Del Sol Fernández, S.; García-Salcedo, R.; Sánchez-Guzmán, D.; Ramírez-Rodríguez, G.; Gaona, E.; León-Alfaro, M.A. de; Rivera-Montalvo, T.

    2016-01-01

    The response of TLD-100, CaSO_4:Dy and LiF:Mg,Cu,P for a range of X-ray low dose was measured. For calibration, the TLDs were arranged at the center of the X-ray field. The dose output of the X-ray machine was determined using an ACCU-Gold. All dosimeters were exposed at the available air kerma values of 14.69 mGy within a field 10×10 cm"2 at 80 cm of SSD. Results of LiF:Mg,Cu,P X-ray irradiated showed 4.8 times higher sensitivity than TLD-100. Meanwhile, TL response of CaSO_4:Dy exposed at the same dose was 5.6 time higher than TLD-100. Experimental results show for low dose X-ray measurements a better linearity for LiF:Mg,Cu,P compared with that of TLD-100. CaSO_4:Dy showed a linearity from 0.1 to 60 mGy - Highlights: • Low dose X-ray doses for personal dosimetry were measured. • Radiation dose (µGy ) for environmental dosimetry were determined. • Scattering radiation dose were measured by TLDs. • Linearity of pair TLD system was successful in the range of microgray. • Pair TLDs composed by CaSO_4:Dy and by LiF:Mg,Cu,P. is suggested for clinical dosimetry.

  2. Low-dose prophylactic craniospinal radiotherapy for intracranial germinoma

    International Nuclear Information System (INIS)

    Schoenfeld, Gordon O.; Amdur, Robert J.; Schmalfuss, Ilona M.; Morris, Christopher G.; Keole, Sameer R.; Mendenhall, William M.; Marcus, Robert B.

    2006-01-01

    Purpose: To report outcomes of patients with localized intracranial germinoma treated with low-dose craniospinal irradiation (CSI) followed by a boost to the ventricular system and primary site. Methods and Materials: Thirty-one patients had pathologically confirmed intracranial germinoma and no spine metastases. Low-dose CSI was administered in 29 patients: usually 21 Gy of CSI, 9.0 Gy of ventricular boost, and a 19.5-Gy tumor boost, all at 1.5 Gy per fraction. Our neuroradiologist recorded three-dimensional tumor size on magnetic resonance images before, during, and after radiotherapy. Results: With a median follow-up of 7.0 years, 29 of 31 patients (94%) are disease free. One failure had nongerminomatous histology; the initial diagnosis was a sampling error. Of 3 patients who did not receive CSI, 1 died. No patient developed myelopathy, visual deficits, dementia, or skeletal growth problems. In locally controlled patients, tumor response according to magnetic resonance scan was nearly complete within 6 months after radiotherapy. Conclusions: Radiotherapy alone with low-dose prophylactic CSI cures almost all patients with localized intracranial germinoma. Complications are rare when the daily dose of radiotherapy is limited to 1.5 Gy and the total CSI dose to 21 Gy. Patients without a near-complete response to radiotherapy should undergo resection to rule out a nongerminomatous element

  3. Ageing effects of polymers at very low dose-rates

    International Nuclear Information System (INIS)

    Chenion, J.; Armand, X.; Berthet, J.; Carlin, F.; Gaussens, G.; Le Meur, M.

    1987-10-01

    The equipment irradiation dose-rate into the containment is variable from 10 -6 to 10 -4 gray per second for the most exposed materials. During qualification, safety equipments are submitted in France to dose-rates around 0.28 gray per second. This study purpose is to now if a so large irradiation dose-rate increase is reasonable. Three elastomeric materials used in electrical cables, o'rings seals and connectors, are exposed to a very large dose-rates scale between 2.1.10 -4 and 1.4 gray per second, to 49 KGy dose. This work was carried out during 3.5 years. Oxygen consumption measurement of the air in contact with polymer materials, as mechanical properties measurement show that: - at very low dose-rate, oxygen consumption is maximum at the same time (1.4 year) for the three elastomeric samples. Also, mechanical properties simultaneously change with oxygen consumption. At very low dose-rate, for the low irradiation doses, oxygen consumption is at least 10 times more important that it is showed when irradiation is carried out with usual material qualification dose-rate. At very low dose-rate, oxygen consumption decreases when absorbed irradiation dose by samples increases. The polymer samples irradiation dose is not still sufficient (49 KGy) to certainly determine, for the three chosen polymer materials, the reasonable irradiation acceleration boundary during nuclear qualification tests [fr

  4. Biochemical and cellular mechanisms of low-dose effects

    International Nuclear Information System (INIS)

    Feinendegen, L.E.; Booz, J.; Muehlensiepen, H.

    1988-01-01

    The question of health effects from small radiation doses remains open. Individual cells, when being hit by single elemental doses - in low-dose irradiation - react acutely and temporarily by altering control of enzyme activity, as is demonstrated for the case of thymidine kinase. This response is not constant in that it provides a temporary protection of enzyme activity against a second irradiation, by a mechanism likely to be via improved detoxification of intracellular radicals. It must be considered that in the low-dose region radiation may also exert protection against other challenges involving radicals, causing a net beneficial effect by temporarily shielding the hit cell against radicals produced by metabolism. Since molecular alterations leading to late effects are considered a consequence of the initial cellular response, late effects from small radiation doses do not necessarily adhere to a linear dose-effect relationship. The reality of the linear relationship between the risk of late effects from high doses to small doses is an assumption, for setting dose limits, but it must not be taken for predicting health detriment from low doses. (author)

  5. Exercise and sport performance with low doses of caffeine.

    Science.gov (United States)

    Spriet, Lawrence L

    2014-11-01

    Caffeine is a popular work-enhancing supplement that has been actively researched since the 1970s. The majority of research has examined the effects of moderate to high caffeine doses (5-13 mg/kg body mass) on exercise and sport. These caffeine doses have profound effects on the responses to exercise at the whole-body level and are associated with variable results and some undesirable side effects. Low doses of caffeine (caffeine doses (1) do not alter the peripheral whole-body responses to exercise; (2) improve vigilance, alertness, and mood and cognitive processes during and after exercise; and (3) are associated with few, if any, side effects. Therefore, the ergogenic effect of low caffeine doses appears to result from alterations in the central nervous system. However, several aspects of consuming low doses of caffeine remain unresolved and suffer from a paucity of research, including the potential effects on high-intensity sprint and burst activities. The responses to low doses of caffeine are also variable and athletes need to determine whether the ingestion of ~200 mg of caffeine before and/or during training and competitions is ergogenic on an individual basis.

  6. Plants as warning signal for exposure to low dose radiation

    International Nuclear Information System (INIS)

    Rusli Ibrahim; Norhafiz Talib

    2012-01-01

    The stamen-hair system of Tradescantia for flower colour has proven to be one of the most suitable materials to study the frequency of mutations induced by low doses of various ionizing radiations and chemical mutagens. The system has also been used successfully for detecting mutagenic synergisms among chemical mutagens and ionizing radiations as well as for studying the variations of spontaneous mutation frequency. In this study of radiobiology, the main objective is to observe somatic mutation (occurrence of pink cells from blue cells) induced on stamen hairs of five Tradescantia sp. available in Malaysia after exposure to low doses of chronic gamma irradiation using Gamma Green House. Pink cells appeared only on Tradescantia Pallida Purpurea stamen hairs after 13 days of exposure to irradiation with different doses of gamma rays. The highest number of stamens with pink cells was recorded from flowers irradiated with the highest dose of 6.37 Gy with 0.07 Gy/ h of dose rate. The lowest number of stamens with pink cells was recorded with an average of 0.57, irradiated with the lowest dose of 0.91 Gy with 0.01 Gy/ h of dose rate. There were no pink cells observed on Tradescantia Spathaceae Discolor after exposure to different doses of gamma rays. Similar negative results were observed for the control experiments. The principal cells in this assay are the mitotic stamen hair cells developing in the young flower buds. After exposure to radiation, the heterozygous dominant blue character of the stamen hair cell is prevented, resulting in the appearance of the recessive pink color. Furthermore, no pink cell appears on all species of Tradescantia spathaceae after irradiated with different doses of gamma rays. The sensitivity of the Tradescantia has been used widely and has demonstrated the relation between radiation dose and frequency of mutation observed at low doses which can contribute to the effects of low doses and their consequences for human health. This system

  7. Intracranial germinomas: a case for low dose radiation therapy alone

    International Nuclear Information System (INIS)

    Harrigan, Patricia M.; Loeffler, Jay S.; Shrieve, Dennis; Tarbell, Nancy J.

    1995-01-01

    Purpose: To determine the optimal dose and treatment outcome of patients treated with radiation for intracranial germinoma. Materials and Methods: Between 1975 and 1995, 39 patients with a diagnosis of intracranial germinoma were treated with radiation (RT) to the central nervous system. All but one pt received whole brain (WB) RT, (median dose: 3240 cGy range: 1500-4437 cGy) and a boost to the tumor volume (median total tumor volume dose: 5200 cGy, range: 3960-5950 cGy). Thirty-one pts received RT to the spine (median dose: 2500, range: 1875-3750). Eleven pts were treated with low dose RT and a tumor volume boost, (WB dose ≤ 2550 cGy, and spine dose ≤ 2160 cGy). Five pts were treated with cisplatin-based chemotherapy and low dose WB RT. Fifteen pts were biopsy-proven and 18 presented with multiple midline germinomas (MMG). Among all pts, 33% had serum or CSF positive for low levels of HCG and none of 19 (9 biopsy-proven) germinomas measured positive for AFP tumor marker. Six of 22 (27%) pts who had spine imaging or CSF cytology had evidence of tumor seeding. The male-to female-ratio was 1.4. Median age at diagnosis was 14 yrs for male pts and 9.5 yrs for females (p=.02, overall age range: 1-31 yrs). Median follow-up for survivors is 64 months (range: 1-226 months). Toxicity of treatment relative to dose was assessed. Results: The 5-yr. actuarial rate of disease-free survival (DFS) and overall survival for presumed germinomas was 97%. No pts died of germinoma. One pt died of a shunt infection who had received concurrent chemotherapy and low dose whole brain RT. Among the low dose RT alone group 6 pts received whole brain RT of ≤ 2550 cGy and 9 pts were treated with spinal RT of ≤ 2160 cGy without chemotherapy. Two of these pts had CSF cytology positive for tumor seeding. Additionally, 8 pts received a total dose to the tumor volume of ≤ 4800 cGy without chemotherapy. The 5-yr DFS was 100%. Five pts were treated with cisplatin-based chemotherapy followed

  8. Intracranial germinomas: a case for low dose radiation therapy alone

    Energy Technology Data Exchange (ETDEWEB)

    Harrigan, Patricia M; Loeffler, Jay S; Shrieve, Dennis; Tarbell, Nancy J

    1995-07-01

    Purpose: To determine the optimal dose and treatment outcome of patients treated with radiation for intracranial germinoma. Materials and Methods: Between 1975 and 1995, 39 patients with a diagnosis of intracranial germinoma were treated with radiation (RT) to the central nervous system. All but one pt received whole brain (WB) RT, (median dose: 3240 cGy range: 1500-4437 cGy) and a boost to the tumor volume (median total tumor volume dose: 5200 cGy, range: 3960-5950 cGy). Thirty-one pts received RT to the spine (median dose: 2500, range: 1875-3750). Eleven pts were treated with low dose RT and a tumor volume boost, (WB dose {<=} 2550 cGy, and spine dose {<=} 2160 cGy). Five pts were treated with cisplatin-based chemotherapy and low dose WB RT. Fifteen pts were biopsy-proven and 18 presented with multiple midline germinomas (MMG). Among all pts, 33% had serum or CSF positive for low levels of HCG and none of 19 (9 biopsy-proven) germinomas measured positive for AFP tumor marker. Six of 22 (27%) pts who had spine imaging or CSF cytology had evidence of tumor seeding. The male-to female-ratio was 1.4. Median age at diagnosis was 14 yrs for male pts and 9.5 yrs for females (p=.02, overall age range: 1-31 yrs). Median follow-up for survivors is 64 months (range: 1-226 months). Toxicity of treatment relative to dose was assessed. Results: The 5-yr. actuarial rate of disease-free survival (DFS) and overall survival for presumed germinomas was 97%. No pts died of germinoma. One pt died of a shunt infection who had received concurrent chemotherapy and low dose whole brain RT. Among the low dose RT alone group 6 pts received whole brain RT of {<=} 2550 cGy and 9 pts were treated with spinal RT of {<=} 2160 cGy without chemotherapy. Two of these pts had CSF cytology positive for tumor seeding. Additionally, 8 pts received a total dose to the tumor volume of {<=} 4800 cGy without chemotherapy. The 5-yr DFS was 100%. Five pts were treated with cisplatin-based chemotherapy

  9. Chronic hypersensitivity pneumonitis.

    Science.gov (United States)

    Pereira, Carlos Ac; Gimenez, Andréa; Kuranishi, Lilian; Storrer, Karin

    2016-01-01

    Hypersensitivity pneumonitis (HSP) is a common interstitial lung disease resulting from inhalation of a large variety of antigens by susceptible individuals. The disease is best classified as acute and chronic. Chronic HSP can be fibrosing or not. Fibrotic HSP has a large differential diagnosis and has a worse prognosis. The most common etiologies for HSP are reviewed. Diagnostic criteria are proposed for both chronic forms based on exposure, lung auscultation, lung function tests, HRCT findings, bronchoalveolar lavage, and biopsies. Treatment options are limited, but lung transplantation results in greater survival in comparison to idiopathic pulmonary fibrosis. Randomized trials with new antifibrotic agents are necessary.

  10. New approach for food allergy management using low-dose oral food challenges and low-dose oral immunotherapies.

    Science.gov (United States)

    Yanagida, Noriyuki; Okada, Yu; Sato, Sakura; Ebisawa, Motohiro

    2016-04-01

    A number of studies have suggested that a large subset of children (approximately 70%) who react to unheated milk or egg can tolerate extensively heated forms of these foods. A diet that includes baked milk or egg is well tolerated and appears to accelerate the development of regular milk or egg tolerance when compared with strict avoidance. However, the indications for an oral food challenge (OFC) using baked products are limited for patients with high specific IgE values or large skin prick test diameters. Oral immunotherapies (OITs) are becoming increasingly popular for the management of food allergies. However, the reported efficacy of OIT is not satisfactory, given the high frequency of symptoms and requirement for long-term therapy. With food allergies, removing the need to eliminate a food that could be consumed in low doses could significantly improve quality of life. This review discusses the importance of an OFC and OIT that use low doses of causative foods as the target volumes. Utilizing an OFC or OIT with a low dose as the target volume could be a novel approach for accelerating the tolerance to causative foods. Copyright © 2015 Japanese Society of Allergology. Production and hosting by Elsevier B.V. All rights reserved.

  11. Modulation of DNA polymerase beta-dependent base excision repair in cultured human cells after low dose exposure to arsenite

    International Nuclear Information System (INIS)

    Sykora, Peter; Snow, Elizabeth T.

    2008-01-01

    Base excision repair (BER) is crucial for development and for the repair of endogenous DNA damage. However, unlike nucleotide excision repair, the regulation of BER is not well understood. Arsenic, a well-established human carcinogen, is known to produce oxidative DNA damage, which is repaired primarily by BER, whilst high doses of arsenic can also inhibit DNA repair. However, the mechanism of repair inhibition by arsenic and the steps inhibited are not well defined. To address this question we have investigated the regulation of DNA polymerase β (Pol β) and AP endonuclease (APE1), in response to low, physiologically relevant doses of arsenic. GM847 lung fibroblasts and HaCaT keratinocytes were exposed to sodium arsenite, As(III), and mRNA, protein levels and BER activity were assessed. Both Pol β and APE1 mRNA exhibited significant dose-dependant down regulation at doses of As(III) above 1 μM. However, at lower doses Pol β mRNA and protein levels, and consequently, BER activity were significantly increased. In contrast, APE1 protein levels were only marginally increased by low doses of As(III) and there was no correlation between APE1 and overall BER activity. Enzyme supplementation of nuclear extracts confirmed that Pol β was rate limiting. These changes in BER correlated with overall protection against sunlight UV-induced toxicity at low doses of As(III) and produced synergistic toxicity at high doses. The results provide evidence that changes in BER due to low doses of arsenic could contribute to a non-linear, threshold dose response for arsenic carcinogenesis

  12. The effect of 'allergenic' and 'nonallergenic' antibiotics on dog keratinocyte viability in vitro.

    Science.gov (United States)

    Voie, Katrine L; Lucas, Benjamin E; Schaeffer, David; Kim, Dewey; Campbell, Karen L; Lavergne, Sidonie N

    2013-10-01

    Immune-mediated adverse drug reactions (drug hypersensitivity) are relatively common in veterinary medicine, but their pathogenesis is not well understood. For an unknown reason, delayed drug hypersensitivity often targets the skin. Antibiotics, especially β-lactams and sulfonamides, are commonly associated with these adverse events. The 'danger theory' hypothesizes that 'danger' signals, such as drug-induced cell death, might be part of the pathogenesis of drug hypersensitivity reactions. The goal of this study was to determine whether antibiotics that are commonly associated with cutaneous drug hypersensitivity (allergenic) decrease canine keratinocyte viability in vitro more than antibiotics that rarely cause such reactions (nonallergenic). Immortalized canine keratinocytes (CPEK cells) were exposed to a therapeutic range of drug concentrations of four 'allergenic' antibiotics (two β-lactams, i.e. amoxicillin and cefalexin, and two sulfonamides, i.e. sulfamethoxazole and sulfadimethoxine) or two 'nonallergenic' antibiotics (enrofloxacin and amikacin) over 48 h (2, 4, 8, 24 and 48 h). The reactive nitroso metabolite of sulfamethoxazole was also tested. Cefalexin (2 mmol/L) significantly decreased cell viability after 48 h (28 ± 7%; P = 0.035). The nitroso metabolite of sulfamethoxazole (100 μmol/L) decreased cell viability after 2 h (21 ± 7%; P = 0.049), but cell numbers were increased after 8 h (22 ± 6%; P = 0.018). In addition, enrofloxacin (500 μmol/L) also significantly decreased cell viability by 37% (±6%; P = 0.0035) at 24 h and by 70% (±8%; P good predictor of the 'allergenic' potential of an antibiotic. Further work is required to investigate other drug-induced 'danger' signals in dog keratinocytes exposed to 'allergenic' antibiotics in vitro. © 2013 ESVD and ACVD.

  13. Drug hypersensitivity syndrome

    Directory of Open Access Journals (Sweden)

    Rashmi Kumari

    2011-01-01

    Full Text Available Drug hypersensitivity syndrome (DHS is an adverse drug reaction commonly associated with the aromatic antiepileptic drugs (AEDs, viz., phenytoin (PHT, carbamazepine (CBZ, phenobarbital (PB, lamotrigine, primidone, etc. It can also be caused by other drugs, such as sulfonamides, dapsone, minocycline, gold derivatives, cyclosporine, captopril, diltiazem, terbinafine, azathioprine and allopurinol. Diagnosis of DHS may be difficult because of the variety of clinical and laboratory abnormalities and manifestations and because the syndrome may mimic infectious, neoplastic or collagen vascular disorders. The risk for developing hypersensitivity within 60 days of the first or second prescription in new users of PHT or CBZ was estimated to be 2.3-4.5 per 10,000 and 1-4.1 per 10,000, respectively. The syndrome is defined by the fever, skin rash, lymphadenopathy and internal organ involvement within the first 2-8 weeks after initiation of therapy. Internal manifestations include, among others, agranulocytosis, hepatitis, nephritis and myositis. Insufficient detoxification may lead to cell death or contribute to the formation of antigen that triggers an immune reaction. Cross-reactivity among PHT, CBZ and PB is as high as 70%-80%. Management mainly includes immediate withdrawal of the culprit drug, symptomatic treatment and systemic steroids or immunoglobulins.

  14. Low-dose CT: new tool for screening lung cancer?

    International Nuclear Information System (INIS)

    Diederich, S.; Wormanns, D.; Heindel, W.

    2001-01-01

    Lung cancer is the leading cause of death from malignant tumours as it is very common and has a poor prognosis at advanced tumour stages. Prognosis could be improved by treatment at early stages. As these stages are usually asymptomatic, a diagnostic test that would allow detection of early tumour stages in a population at risk could potentially reduce mortality from lung cancer. Previous approaches using chest radiography and sputum cytology in smokers have been disappointing. Fluorescent bronchoscopy and molecular markers are not yet applicable in clinical routine. Because of its high sensitivity for small pulmonary nodules, which are the most common manifestation of early lung cancer, CT appears suitable as a screening test. Low-dose examination parameters can and should be used for this purpose. From clinical practice it is well known that chest CT often demonstrates small pulmonary nodules, which do not represent lung cancer. Therefore, non-invasive diagnostic algorithms are required to avoid unnecessary biopsies in benign lesions. In preliminary studies of low-dose CT using algorithms based on size and density of detected nodules a large proportion of asymptomatic lung cancers and a large proportion of early, resectable tumour stages were found with a small proportion of invasive procedures for benign nodules. Before this technology can be recommended for broad application, however, further information is required regarding appropriate inclusion criteria (smoking habits, age groups) and screening intervals. Most importantly, further data are required to clarify whether lung cancer screening using low-dose CT can actually reduce mortality from lung cancer. (orig.)

  15. Low-dose multislice CT in febrile neutropenic patients

    International Nuclear Information System (INIS)

    Wendel, F.; Jenett, M.; Hahn, D.; Sandstede, J.; Geib, A.

    2005-01-01

    Purpose: to define the value of low-dose multislice CT in a clinical setting for early detection of pneumonia in neutropenic patients with fever of unknown origin. Materials and methods: thirty-five neutropenic patients suffering from fever of unknown origin with normal chest X-ray underwent unenhanced low-dose CT of the chest (120 kV, 10 eff. mAs, collimation 4 x 1 mm) using a multislice CT scanner. Axial und frontal slices with a thickness of 5 mm were calculated. If no pneumonia was found, standard antibiotics were given and a repeated examination was performed if fever continued. In case of pneumonia, antimycotic therapy was added and a follow-up CT was performed within one week. Regression or progression of pneumonia at follow-up served as evidence of pneumonia; lowering of fever within 48 h or inconspicuous follow-up CT was regarded as absence of pneumonia. Results: ten of 35 patients had pneumonic infiltration, which decreased or increased on follow-up CT in 3 and 6 patients, respectively. One patient revealed leucemic infiltration by bronchoalveolar lavage. Twenty-five of 35 patients had no evidence of pneumonia. Twenty of these patients were free of fever within 48 h under antibiotics; one patient died due to his basic illness. Out of 4 patients with persisting fever, 3 patients had no pneumonia on repeated examination; one patient showed disseminated micronodular infiltration. Frontal reconstructions helped to differentiate infiltration from atelectasis in 4 patients. Sensitivity and specificity for the detection of pneumonia at the first examination were 90% and 96%, negative predictive value was 96%. Conclusion: low-dose multislice CT should be performed in neutropenic patients having a fever of unknown origin and normal chest X-ray. (orig.)

  16. Development of new chemical dosimeter for low dose range

    International Nuclear Information System (INIS)

    Mhatre, Sachin G.V.; Adhikari, S.

    2012-01-01

    Accurate measurement of low dose radiation in complex systems is of utmost importance in radiation biology and related areas. Ferrous Benzoic acid Xylenol orange (FBX) system is being widely used for measurement of low dose gamma radiation because of its reproducibility and precision. However, an additional step, i.e., dissolution of benzoic acid in water at higher temperature followed by cooling at room temperature is involved for the preparation of this dosimeter. This makes it inconvenient as a ready to use dosimeter. In the present work, the organic molecule, sorbitol has been used for measurement of low doses of radiation. The advantages of using sorbitol are its ready availability and instantaneous water solubility. Owing to its dissolution at room temperature, possible errors those are involved in calculation of dose due to thermal oxidation of ferrous ions during preparation of the FBX dosimetric solution could be made insignificant in the proposed dosimeter. In the present system, sorbitol acts as radiolytic sensitizer for the oxidation of ferrous ion, and xylenol orange forms a 1:1 complex specifically with ferric ions. Thus, the analytical detection limit of ferric ions is enhanced compared to other systems. Final composition of the dosimetric solution is; 0.5 mol/m 3 xylenol orange, 10 mol/m 3 sorbitol and 0.2 mol/m 3 ferrous ion in 50 mol/m 3 sulfuric acid. Radiolytic sensitization in combination with analytical enhancement of the ferrous based system, allows us to measure radiation dose in the range of 0.05 Gy–12 Gy with ease and high reproducibility.

  17. Uncommon toxicity of low-dose methotrexate: case report

    Directory of Open Access Journals (Sweden)

    Zohreh Yousefi

    2015-10-01

    Full Text Available Background: Standard treatment of Gestational Trophoblastic Disease (GTD is chemotherapy. Single-agent chemotherapy regime including Methotrexate (MTX or Actinomycin. Single-agent is widely used in treatment of persistent trophoblastic disease. We reported an uncommon toxicity of low-dose single-agent methotrexate in a patient. Case Presentation: A 20-year-old woman, primary gravid after two months missed period and spotting with diagnosis of incomplete abortion with uterine size equivalent of ten weeks pregnancy (8-10 cm underwent evacuation curettage. In serial follow-up, based on rise of beta-hCG titer and absence of metastatic disease, it was categorized as low-risk persistent trophoblastic disease. She was referred to gynecology oncology center of Ghaem Hospital, Mashhad University of Medical Sciences in May 2014. Because of rise of beta-hCG titer, after complete metastatic work-up and lack of disease in other sites, persistent disease was diagnosed and candidate for chemotherapy (single agent low-dose. The patient received first course of therapy with MTX (50 mg/m², intra muscular. Unfortunately, after two days of treatment she developed uncommon severe toxicity, fever, severe nausea and vomiting, tachycardia, and generalized weakness. Also, we found hematologic abnormality (WBC: -14000-15000 µI, platelet- 540 µI and sever neutropenia, and abnormal rising in liver function test (SGOT, SGPT (three to four times and renal function test (BUN and Creatinine (two times. In addition, she had disseminated erosive lesion in all of body especially in face. Due to the fatal side effects of chemotherapy, she was admitted to intensive care unit (ICU. Fortunately, after two to three weeks, she was improved by conservative management. After few weeks beta-hCG titer was in normal limit. However she had normal serial beta-hCG in one year of follow-up. Conclusion: It is important to emphasis unpredictable side effects of chemotherapy with low-dose

  18. Exposure to low dose ionising radiation: Molecular and clinical consequences.

    LENUS (Irish Health Repository)

    Martin, Lynn M

    2014-07-10

    This review article provides a comprehensive overview of the experimental data detailing the incidence, mechanism and significance of low dose hyper-radiosensitivity (HRS). Important discoveries gained from past and present studies are mapped and highlighted to illustrate the pathway to our current understanding of HRS and the impact of HRS on the cellular response to radiation in mammalian cells. Particular attention is paid to the balance of evidence suggesting a role for DNA repair processes in the response, evidence suggesting a role for the cell cycle checkpoint processes, and evidence investigating the clinical implications\\/relevance of the effect.

  19. Harderian Gland Tumorigenesis: Low-Dose and LET Response

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Polly Y. [SRI International, Menlo Park, CA (United States). Biosciences Div.; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Life Sciences Div.; Cucinotta, Francis A. [Univ. of Nevada, Las Vegas, NV (United States). Dept. of Health Physics and Diagnostic Sciences; Bjornstad, Kathleen A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Life Sciences Div.; Bakke, James [SRI International, Menlo Park, CA (United States). Biosciences Div.; Rosen, Chris J. [SRI International, Menlo Park, CA (United States). Biosciences Div.; Du, Nicholas [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Life Sciences Div.; Fairchild, David G. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Life Sciences Div.; Cacao, Eliedonna [Univ. of Nevada, Las Vegas, NV (United States). Dept. of Health Physics and Diagnostic Sciences; Blakely, Eleanor A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Life Sciences Div.

    2016-04-19

    Increased cancer risk remains a primary concern for travel into deep space and may preclude manned missions to Mars due to large uncertainties that currently exist in estimating cancer risk from the spectrum of radiations found in space with the very limited available human epidemiological radiation-induced cancer data. Existing data on human risk of cancer from X-ray and gamma-ray exposure must be scaled to the many types and fluences of radiations found in space using radiation quality factors and dose-rate modification factors, and assuming linearity of response since the shapes of the dose responses at low doses below 100 mSv are unknown. The goal of this work was to reduce uncertainties in the relative biological effect (RBE) and linear energy transfer (LET) relationship for space-relevant doses of charged-particle radiation-induced carcinogenesis. The historical data from the studies of Fry et al. and Alpen et al. for Harderian gland (HG) tumors in the female CB6F1 strain of mouse represent the most complete set of experimental observations, including dose dependence, available on a specific radiation-induced tumor in an experimental animal using heavy ion beams that are found in the cosmic radiation spectrum. However, these data lack complete information on low-dose responses below 0.1 Gy, and for chronic low-dose-rate exposures, and there are gaps in the LET region between 25 and 190 keV/μm. In this study, we used the historical HG tumorigenesis data as reference, and obtained HG tumor data for 260 MeV/u silicon (LET ~70 keV/μm) and 1,000 MeV/u titanium (LET ~100 keV/μm) to fill existing gaps of data in this LET range to improve our understanding of the dose-response curve at low doses, to test for deviations from linearity and to provide RBE estimates. Animals were also exposed to five daily fractions of 0.026 or 0.052 Gy of 1,000 MeV/u titanium ions to simulate chronic exposure, and HG tumorigenesis from this fractionated study were compared to the

  20. Effect of low doses of ionizing radiation on human health

    International Nuclear Information System (INIS)

    Kovalenko, A.N.

    1990-01-01

    Data are reported on the possible mechanism of biological effects of low doses of ionizing radiation on the human body. The lesioning effect of this radiation resulted in some of the persons in the development of disorders of the function of information and vegetative-regulatory systems determined as a desintegration syndrome. This syndrome is manifested in unspecific neuro-vegetative disorders of the function of most important physiological and homeostatic system of the body leading to weakening of the processes of compensation and adaptation. This condition is characterized by an unspecific radiation syndrome as distinct from acute or chronic radiation disease which is a specific radiation syndrome

  1. Low-Dose Radiation Induces Genes Promoting Cell Survival

    International Nuclear Information System (INIS)

    Liu, Shu-Zheng; Chen, Dong; Mu, Ying

    1999-01-01

    Apoptosis is an important process controlling homeostasis of the body. It is influenced by stimuli constantly arising from the external and internal environment of the organism. It is well known that radiation could induce apoptosis of cells in vitro and in vivo. However, the dose-effect relationship of apoptosis extending to the low-dose range has scarcely been studied. Here, the molecular basis of the phenomenon is explored by examining the changes in expression of some of the proapoptotic and antiapoptotic genes

  2. A consideration of low dose radiation effects on human health

    International Nuclear Information System (INIS)

    Shimada, Yoshiya; Nishimura, Mayumi; Imaoka, Tatsuhiko; Kakinuma, Shizuko

    2011-01-01

    On March 11, 2011, an earthquake categorized as 9 Mw occurred off the northeast coast of Japan. The subsequent destructive tsunami disabled emergency units of Fukushima Dai'ichi Nuclear Power Plant and caused partial meltdown of reactors and explosions. Resulting radiation releases forced large evacuations, bore concerns about food and water and fears against human health. In this manuscript, we described the effect of radiation, especially low dose radiation below 100 mSv, on cancer risk, focusing on fetuses and children. (author)

  3. Anti-tumor effect of low dose radiation in mice

    International Nuclear Information System (INIS)

    Fan Zhengping; Lu Jiaben; Zhu Bingchai

    1997-01-01

    The author reports the effects of the total body irradiation of low dose radiation (LDR) and/or the local irradiation of large dose on average tumor weights and tumor inhibitory rates in 170 mice inoculated S 180 sarcoma cell, and the influence of LDR on average longevity in 40 tumor-bearing animals. Results show (1) LDR in the range of 75∼250 mGy can inhibit tumor growth to some extent; (2) fractionated irradiation of 75 mGy and local irradiation of 10 Gy may produce a synergism in tumor growth inhibition; and (3)LDR may enhance average longevity in ascitic tumor-bearing mice

  4. Uterine malignant degeneration after low-dose endometrial irradiation

    International Nuclear Information System (INIS)

    Nikkanen, V.; Salmi, T.; Groenroos, M.

    1980-01-01

    The effectiveness of low-dose intrauterine irradiation for benign diseases and its possible carcinogenic effect on the uterus was studied in 190 patients who were treated during the years 1952-1974. The indications for irradiation were premenopausal functional bleeding, leukemia, hemophilia, fibroids, endometriosis or other benign reason. Radiation was also performed on patients with severe neurologic diseases that contraindicated surgery and on some mentally retarded patients whose restlessness and epileptic seizures were aggravated premenstrually and during menstruation. The mean follow-up period was 15 years. Uterine bleeding recurred in 21 percent of the patients. No cases of uterine malignant degeneration were found. (author)

  5. From Chernobyl to Fukushima: the effect of low doses

    International Nuclear Information System (INIS)

    Aurengo, A.

    2011-01-01

    This Power Point presentation describes the Fukushima's reactors, recalls some data about the earthquake and tsunami, and indicates their consequences for the operation of the power station (notably the loss of cooling means). It identifies some design errors for the Chernobyl's and Fukushima's power stations, outlines differences between these two cases. It gives assessment of doses receives by external irradiation around Fukushima, of the dose rate evolution, of the sea contamination. It gives some data about the Chernobyl accident (radioactivity evolution). After some data about health consequences of Chernobyl, health risks and more particularly biological risks associated to low doses are described. Protection measures are evoked, as well as psycho-social impacts

  6. Application of low dose radiation for preservation of sea foods

    International Nuclear Information System (INIS)

    Venugopal, V.; Nair, P.M.

    1994-01-01

    Treatment of food with low doses of gamma radiation has been recognized to have two main advantages. These consist of: (1) improvement of food safety by elimination of pathogens and (2) reduction of microbial spoilage and extension of shelf life of perishable items by reducing the number of viable spoilage organisms. Studies during the last few decades have conclusively proved the beneficial effects of radiation with respect to fishery products. The three potential areas of application to fish products include: (i) radurization for shelf life extension (ii) radicidation to eliminate food borne pathogens in the products and (iii) radiation treatment to dried products to control insects

  7. Biologically based modelling and simulation of carcinogenesis at low doses

    International Nuclear Information System (INIS)

    Ouchi, Noriyuki B.

    2003-01-01

    The process of the carcinogenesis is studied by computer simulation. In general, we need a large number of experimental samples to detect mutations at low doses, but in practice it is difficult to get such a large number of data. To satisfy the requirements of the situation at low doses, it is good to study the process of carcinogenesis using biologically based mathematical model. We have mainly studied it by using as known as 'multi-stage model'; the model seems to get complicated, as we adopt the recent new findings of molecular biological experiments. Moreover, the basic idea of the multi-stage model is based on the epidemiologic data of log-log variation of cancer incidence with age, it seems to be difficult to compare with experimental data of irradiated cell culture system, which has been increasing in recent years. Taking above into consideration, we concluded that we had better make new model with following features: 1) a unit of the target system is a cell, 2) the new information of the molecular biology can be easily introduced, 3) having spatial coordinates for checking a colony formation or tumorigenesis. In this presentation, we will show the detail of the model and some simulation results about the carcinogenesis. (author)

  8. Low-dose aripiprazole for refractory burning mouth syndrome

    Directory of Open Access Journals (Sweden)

    Umezaki Y

    2016-05-01

    Full Text Available Yojiro Umezaki,1 Miho Takenoshita,2 Akira Toyofuku2 1Psychosomatic Dentistry Clinic, Dental Hospital, 2Psychosomatic Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan Abstract: We report a case of refractory burning mouth syndrome (BMS ameliorated with low dose of aripiprazole. The patient was a 66-year-old female who had suffered from chronic burning pain in her tongue for 13 months. No abnormality associated with the burning sensation was detected in the laboratory tests and the oral findings. Considering the clinical feature and the history together, we diagnosed the burning sensation as BMS. The BMS pain was decreased by aripiprazole (powder 1.0 mg/d, though no other antidepressants had satisfying pain relief. It could be supposed that the efficacy of aripiprazole is caused by dopamine stabilization in this case, and BMS might have a subtype that is reactive to aripiprazole. Further studies are needed to confirm the efficacy of aripiprazole for BMS. Keywords: burning mouth syndrome, low-dose aripiprazole, chronic pain

  9. Low doses of neutrons induce changes in gene expression

    International Nuclear Information System (INIS)

    Woloschak, G.E.; Chang-Liu, C.M.; Panozzo, J.; Libertin, C.R.

    1993-01-01

    Studies were designed to identify genes induced following low-dose neutron but not following γ-ray exposure in fibroblasts. Our past work had shown differences in the expression of β-protein kinase C and c-fos genes, both being induced following γ-ray but not neutron exposure. We have identified two genes that are induced following neutron, but not γ-ray, exposure: Rp-8 (a gene induced by apoptosis) and the long terminal repeat (LTR) of the human immunodeficiency (HIV). Rp-8 mRNA induction was demonstrated in Syrian hamster embryo fibroblasts and was found to be induced in cells exposed to neutrons administered at low (0.5 cGy/min) and at high dose rate (12 cGy/min). The induction of transcription from the LTR of HIV was demonstrated in HeLa cells bearing a transfected construct of the chloramphenicol acetyl transferase (CAT) gene driven by the HIV-LTR promoter. Measures of CAT activity and CAT transcripts following irradiation demonstrated an unresponsiveness to γ rays over a broad range of doses. Twofold induction of the HIV-LTR was detected following neutron exposure (48 cGy) administered at low (0.5 cGy/min) but not high (12 cGy/min) dose rates. Ultraviolet-mediated HIV-LTR induction was inhibited by low-dose-rate neutron exposure

  10. Low dose iodine-131 therapy in solitary toxic thyroid nodules

    International Nuclear Information System (INIS)

    Prakash, Rajeev

    1999-01-01

    Forty patients with solitary hyperfunctioning thyroid nodules were treated with relatively low dose radioiodine therapy, 131 I doses were calculated taking into account thyroid mass and radioiodine kinetics to deliver 100 μCi/g of estimated nodule weight corrected for uptake. Patients remaining persistently hyperthyroid at four months after the initial therapy were retreated with a similarly calculated dose. Cure of the hyperthyroid state was achieved in all patients, total administered dose in individual cases ranging from 3-17 mCi. 28 of the 40 patients required a single therapy dose. 36 patients were euthyroid after a 4.5 year mean follow-up period. Four cases developed post therapy hypothyroidism requiring replacement therapy. Nodules regressed completely in nine cases following 131 I treatment, with partial regression in size in 19 patients. Control of hyperthyroid state in cases of solitary toxic thyroid nodules can be satisfactorily achieved using relatively low dose radioiodine therapy with low incidence of post therapy hypothyroidism. (author)

  11. Development of microcontroller based instrumentation for low dose implantation

    International Nuclear Information System (INIS)

    Suresh, K.; Saravanan, K.; Panigrahi, B.K.; Nair, K.G.M.

    2011-01-01

    In experiments like ion implantation based ion track formations, the sample is implanted to low doses of the order of 10 10 ions/cm 2 , limiting the ion beam currents to be less than 1-5 x 10 -12 A. However the standard current integrators available are not sensitive to very low currents, causing an unacceptable high level of error in dose measurement. Hence a low dose implantation measurement system has been developed. It consists of a very sensitive low current preamplifier with full scale input 1nA/100pA, a standard current integrator, a microcontroller based interface circuit, which are connected to a personal computer(PC) through USB. Two types of the software are developed for the system: the microcontroller firmware using C and windows based virtual instrument programs using LabVIEW 7.0. Necessary precautions associated with pA level measurement like rigidly fastened good quality cables, low ripple DC power supply, shielding, close mounting of the preamplifier to the sample are adopted. After necessary calibrations with an ECIL make low current source, the system has been put into regular use. Design and development details, salient features are discussed in this paper. (author)

  12. Exposures at low doses and biological effects of ionizing radiations

    International Nuclear Information System (INIS)

    Masse, R.

    2000-01-01

    Everyone is exposed to radiation from natural, man-made and medical sources, and world-wide average annual exposure can be set at about 3.5 mSv. Exposure to natural sources is characterised by very large fluctuations, not excluding a range covering two orders of magnitude. Millions of inhabitants are continuously exposed to external doses as high as 10 mSv per year, delivered at low dose rates, very few workers are exposed above the legal limit of 50 mSv/year, and referring to accidental exposures, only 5% of the 116 000 people evacuated following the Chernobyl disaster encountered doses above 100 mSv. Epidemiological survey of accidentally, occupationally or medically exposed groups have revealed radio-induced cancers, mostly following high dose-rate exposure levels, only above 100 mSv. Risk coefficients were derived from these studies and projected into linear models of risk (linear non-threshold hypothesis: LNT), for the purpose of risk management following exposures at low doses and low dose-rates. The legitimacy of this approach has been questioned, by the Academy of sciences and the Academy of medicine in France, arguing: that LNT was not supported by Hiroshima and Nagasaki studies when neutron dose was revisited; that linear modelling failed to explain why so many site-related cancers were obviously nonlinearly related to the dose, and especially when theory predicted they ought to be; that no evidence could be found of radio-induced cancers related to natural exposures or to low exposures at the work place; and that no evidence of genetic disease could be shown from any of the exposed groups. Arguments were provided from cellular and molecular biology helping to solve this issue, all resulting in dismissing the LNT hypothesis. These arguments included: different mechanisms of DNA repair at high and low dose rate; influence of inducible stress responses modifying mutagenesis and lethality; bystander effects allowing it to be considered that individual

  13. Food hypersensitivity by inhalation

    Directory of Open Access Journals (Sweden)

    Bahna Sami L

    2009-02-01

    Full Text Available Abstract Though not widely recognized, food hypersensitivity by inhalation can cause major morbidity in affected individuals. The exposure is usually more obvious and often substantial in occupational environments but frequently occurs in non-occupational settings, such as homes, schools, restaurants, grocery stores, and commercial flights. The exposure can be trivial, as in mere smelling or being in the vicinity of the food. The clinical manifestations can vary from a benign respiratory or cutaneous reaction to a systemic one that can be life-threatening. In addition to strict avoidance, such highly-sensitive subjects should carry self-injectable epinephrine and wear MedicAlert® identification. Asthma is a strong predisposing factor and should be well-controlled. It is of great significance that food inhalation can cause de novo sensitization.

  14. Chronic hypersensitivity pneumonitis

    Directory of Open Access Journals (Sweden)

    Pereira CA

    2016-09-01

    Full Text Available Carlos AC Pereira,1 Andréa Gimenez,2 Lilian Kuranishi,2 Karin Storrer 2 1Interstitial Lung Diseases Program, 2Pulmonology Postgraduate, Federal University of São Paulo, São Paulo, Brazil Abstract: Hypersensitivity pneumonitis (HSP is a common interstitial lung disease resulting from inhalation of a large variety of antigens by susceptible individuals. The disease is best classified as acute and chronic. Chronic HSP can be fibrosing or not. Fibrotic HSP has a large differential diagnosis and has a worse prognosis. The most common etiologies for HSP are reviewed. Diagnostic criteria are proposed for both chronic forms based on exposure, lung auscultation, lung function tests, HRCT findings, bronchoalveolar lavage, and biopsies. Treatment options are limited, but lung transplantation results in greater survival in comparison to idiopathic pulmonary fibrosis. Randomized trials with new antifibrotic agents are necessary. Keywords: interstitial lung diseases, extrinsic allergic alveolitis, diffuse lung disease, lung immune response, HRCT, farmers lung

  15. Risk of radiation-induced cancer at low doses and low dose rates for radiation protection purposes

    International Nuclear Information System (INIS)

    1995-01-01

    The aim of this report is to provide an updated, comprehensive review of the data available for assessing the risk of radiation-induced cancer for radiation protection purposes. Particular emphasis is placed on assessing risks at low doses and low dose rates. The review brings together the results of epidemiological investigations and fundamental studies on the molecular and cellular mechanisms involved in radiation damage. Additionally, this information is supplemented by studies with experimental animals which provide further guidance on the form of the dose-response relationship for cancer induction, as well as on the effect of dose rate on the tumour yield. The emphasis of the report is on cancer induction resulting from exposure to radiations with a low linear energy transfer (LET). The work was performed under contract for the Institut de Protection et de Surete Nucleaire, Fontenay-aux-Roses, Paris, France, whose agreement to publish is gratefully ackowledged. It extends the advice on radiation risks given in Documents of the NRPB, 4 No. 4 (1993). (Author)

  16. The health effects of low-dose ionizing radiation

    International Nuclear Information System (INIS)

    Dixit, A.N.; Dixit, Nishant

    2012-01-01

    It has been established by various researches, that high doses of ionizing radiation are harmful to health. There is substantial controversy regarding the effects of low doses of ionizing radiation despite the large amount of work carried out (both laboratory and epidemiological). Exposure to high levels of radiation can cause radiation injury, and these injuries can be relatively severe with sufficiently high radiation doses. Prolonged exposure to low levels of radiation may lead to cancer, although the nature of our response to very low radiation levels is not well known at this time. Many of our radiation safety regulations and procedures are designed to protect the health of those exposed to radiation occupationally or as members of the public. According to the linear no-threshold (LNT) hypothesis, any amount, however small, of radiation is potentially harmful, even down to zero levels. The threshold hypothesis, on the other hand, emphasizes that below a certain threshold level of radiation exposure, any deleterious effects are absent. At the same time, there are strong arguments, both experimental and epidemiological, which support the radiation hormesis (beneficial effects of low-level ionizing radiation). These effects cannot be anticipated by extrapolating from harmful effects noted at high doses. Evidence indicates an inverse relationship between chronic low-dose radiation levels and cancer incidence and/or mortality rates. Examples are drawn from: 1) state surveys for more than 200 million people in the United States; 2) state cancer hospitals for 200 million people in India; 3) 10,000 residents of Taipei who lived in cobalt-60 contaminated homes; 4) high-radiation areas of Ramsar, Iran; 5) 12 million person-years of exposed and carefully selected control nuclear workers; 6) almost 300,000 radon measurements of homes in the United States; and 7) non-smokers in high-radon areas of early Saxony, Germany. This evidence conforms to the hypothesis that

  17. The biological response of plucked human hair to low-dose radiation: a measure of individual radiosensitivity and a technique for biological dosimetry

    International Nuclear Information System (INIS)

    Swain, D.

    1997-01-01

    It is often assumed that the effects of radiation are linear with dose and that high dose effects can be extrapolated to low dose levels. However, there are a variety of mechanisms which can alter the response at low doses. The most important of these relate to induced sensitivity or induced repair mechanisms. It is therefore important that this area is studied in more depth by looking at the molecular effects and damage to cells at low doses. It is well known that there are certain rare genetic syndromes which predispose individuals to cancer, e.g. ataxia telangiectasia. It is also probable that there is a large range of sensitivity in the natural variation of individuals to the risk of radiation-induced cancer. It is proposed that radiosensitivity is studied using stimulated lymphocytes from whole blood and the technique extended to look at the effects in cell cultures established from human hair. Radiation treatment of cell cultures established from plucked human hair has been previously advocated as a non-invasive technique for non-uniform biological dosimetry and it is proposed that these techniques are adapted to the use of hair to estimate individual radiosensitivity. The aim is to establish and optimize these techniques for culturing keratinocytes from plucked human hair follicles with a view to study biological markers for the subsequent assessment of radiosensitivity. Preliminary results are promising and suggest that the technique for culturing keratinocytes from hair presents a feasible approach. Results from this primary cell culture technique and results from the comparison of the micronuclei data obtained from the cell cultures and stimulated lymphocytes will be presented. (author)

  18. The spectrum of mutation produced by low dose radiation

    International Nuclear Information System (INIS)

    Morley, Alexander A.; Turner, David R.

    2004-01-01

    Inherited mutations are the basis of evolution and acquired mutations in humans are important in ageing, cancer and possibly various forms of tissue degeneration. Mutations are responsible for many of the long-term effects of radiation. However, sensitive direct detection of mutations in humans has been difficult. The aims of the project were to develop methods for the sensitive enumeration of mutations in DNA, to measure mutation frequencies in a wide variety of tissue types and to quantify the mutational effect of direct oxidative damage produced by radiation, at both high and low doses. The project was successful in developing a sensitive method which could detect mutations directly in the genetic material, DNA at a sensitivity of 1 mutated molecule in 1000000000 unmutated molecules. However a number of methodological problems had to be overcome and lack of ongoing funding made it impossible to fulfill all of the aims of the project

  19. Low dose response analysis through a cytogenetic end-point

    International Nuclear Information System (INIS)

    Bojtor, I.; Koeteles, G.J.

    1998-01-01

    The effects of low doses were studied on human lymphocytes of various individuals. The frequency of micronuclei in cytokinesis-blocked cultured lymphocytes was taken as end-point. The probability distribution of radiation-induced increment was statistically proved and identified as to be asymmetric when the blood samples had been irradiated with doses of 0.01-0.05 Gy of X-rays, similarly to that in unirradiated control population. On the contrary, at or above 1 Gy the corresponding normal curve could be accepted only reflecting an approximately symmetrical scatter of the increments about their mean value. It was found that the slope as well as the closeness of correlation of the variables considerably changed when lower and lower dose ranges had been selected. Below approximately 0.2 Gy even an unrelatedness was found betwen the absorbed dose and the increment

  20. Metabolomics: new prospects in low-dose radio-toxicology

    International Nuclear Information System (INIS)

    Souidi, Maamar; Grison, Stephane

    2014-01-01

    There is recurring public concern regarding the health impact of chronic exposure to low-dose ionizing radiation. This concern is further heightened when possible sources of exposure are identified, such as disused mines, the operation of nuclear facilities and radioactive waste disposal facilities, accidental release from fuel cycle facilities or the possible return of residents to areas contaminated following a reactor accident, such as the one that occurred at Fukushima. In keeping with the guidelines set out in the European strategic research agenda for MELODI, IRSN is conducting an extensive, largely experiment-based, research program to acquire scientific data to respond to this concern. The program has already revealed that chronic ingestion of cesium-137 or uranium induces many subtle, generally slight, metabolic changes, the overall biological effects of which remain to be studied. A recent 'broad-spectrum' analytical technique known as metabolomics was used to pinpoint these metabolic changes. (authors)

  1. Transcriptome profiling of mice testes following low dose irradiation

    DEFF Research Database (Denmark)

    Belling, Kirstine C.; Tanaka, Masami; Dalgaard, Marlene Danner

    2013-01-01

    ABSTRACT: BACKGROUND: Radiotherapy is used routinely to treat testicular cancer. Testicular cells vary in radio-sensitivity and the aim of this study was to investigate cellular and molecular changes caused by low dose irradiation of mice testis and to identify transcripts from different cell types...... in the adult testis. METHODS: Transcriptome profiling was performed on total RNA from testes sampled at various time points (n = 17) after 1 Gy of irradiation. Transcripts displaying large overall expression changes during the time series, but small expression changes between neighbouring time points were...... selected for further analysis. These transcripts were separated into clusters and their cellular origin was determined. Immunohistochemistry and in silico quantification was further used to study cellular changes post-irradiation (pi). RESULTS: We identified a subset of transcripts (n = 988) where changes...

  2. The effect of low-dose spironolactone on resistant hypertension

    DEFF Research Database (Denmark)

    Engbaek, Mette; Hjerrild, Mette; Hallas, Jesper

    2010-01-01

    with three classes of antihypertensive drugs. The effect on blood pressure was estimated by office measurements together with serum potassium and adverse effects. The data were analyzed retrospectively. A total of 544 patients were identified; 200 were excluded because of secondary hypertension, other......Our objective was to estimate the effect of addition of low-dose spironolactone to previous antihypertensive therapy in patients with resistant hypertension. Patients had 25 to 50 mg of spironolactone once daily added to the treatment of hypertension that was uncontrolled despite previous treatment...... indications for spironolactone than hypertension, previous antihypertensive therapy with less than three drugs unless demonstrated intolerance to a third drug, insufficient compliance, and lack of follow-up data. Thus, 344 cases were included in the analysis. The population was 62.1 ± 12.8 years old, 45...

  3. Low-dose aripiprazole for refractory burning mouth syndrome.

    Science.gov (United States)

    Umezaki, Yojiro; Takenoshita, Miho; Toyofuku, Akira

    2016-01-01

    We report a case of refractory burning mouth syndrome (BMS) ameliorated with low dose of aripiprazole. The patient was a 66-year-old female who had suffered from chronic burning pain in her tongue for 13 months. No abnormality associated with the burning sensation was detected in the laboratory tests and the oral findings. Considering the clinical feature and the history together, we diagnosed the burning sensation as BMS. The BMS pain was decreased by aripiprazole (powder) 1.0 mg/d, though no other antidepressants had satisfying pain relief. It could be supposed that the efficacy of aripiprazole is caused by dopamine stabilization in this case, and BMS might have a subtype that is reactive to aripiprazole. Further studies are needed to confirm the efficacy of aripiprazole for BMS.

  4. 'Reasonable' regulation of low doses in the Netherlands?

    International Nuclear Information System (INIS)

    Zuur, Ciska

    2002-01-01

    As long as it is not clear exactly what the risks of low doses are, exposures should be regulated to be 'as low as reasonably achievable' (ALARA). In radiation protection, for normal situations, this means that a projected dose reduction can only be obligatory when the efforts needed to achieve the reduction are 'reasonable' in comparison with it, economical and social aspects being taken into account. In the recent Dutch regulations, 'reasonable' values have been established for the relevant parameters used in the ALARA concept and the paper discusses the values required to calculate the doses for the critical group due to a source. In some cases, the effort expended in making the ALARA dose assessments might not be reasonable in comparison with the dose reduction to be expected. The system which has been developed in the Netherlands to avoid these 'unreasonable' dose calculations, measurements and assessments is explained. (author)

  5. State of human genome at low-doses ecological influences

    International Nuclear Information System (INIS)

    Mel'nov, S.B.; Rytik, P.G.; Kruchinskij, N.G.; Kovalev, V.A.; Palamar, L.A.; Senyuk, O.F.

    2005-01-01

    The results of analysis of the state of genome (amounts of single strand breaks in DNA) of the persons exposed to influence of complex 'Chernobyl factor' in remote terms after a failure on ChNPP are resulted. Findings allowed to expose the increase of level of single strand breaks in DNA at the chronically irradiated persons mainly carry adaptive character and probably can be related to instability of genome. Thus at organism level growth of mutational pressure and strengthening of instability of cellular genome is related to the change of spectrum of biological characteristics, in particular individual reaction of somatic cells of victims on additional mutagens influences. The indicated changes can testify to existence of potential risk of remote genetic consequences of long-term irradiation influence in low doses

  6. Low-dose irradiation for controlling prostate cancer

    International Nuclear Information System (INIS)

    Cuttler, J.M.

    2003-01-01

    Prostate cancer is the second most commonly diagnosed cancer among North American men and the second leading cause of death in those aged 65 and over. The American Cancer Society recommends testing those over age 50 who are expected to live at least 10 years, even though the ability of early detection to decrease prostate cancer mortality has not been demonstrated. So controversy exists about the appropriateness of screening because of the considerable economic and social burden of diagnosing and treating prostate cancer, coupled with the projected large increase in the number of new cases as the population ages. This very important public health issue could be addressed at low cost by total-body low-dose irradiation therapy to stimulate the patient's own defences to prevent and control most cancers, including prostate cancer, with no symptomatic side effects. (author)

  7. Optical fiber sensor for low dose gamma irradiation monitoring

    Science.gov (United States)

    de Andrés, Ana I.; Esteban, Ã.`scar; Embid, Miguel

    2016-05-01

    An optical fiber gamma ray detector is presented in this work. It is based on a Terbium doped Gadolinium Oxysulfide (Gd2O2S:Tb) scintillating powder which cover a chemically etched polymer fiber tip. This etching improves the fluorescence gathering by the optical fiber. The final diameter has been selected to fulfill the trade-off between light gathering and mechanical strength. Powder has been encapsulated inside a microtube where the fiber tip is immersed. The sensor has been irradiated with different air Kerma doses up to 2 Gy/h with a 137Cs source, and the spectral distribution of the fluorescence intensity has been recorded in a commercial grade CCD spectrometer. The obtained signal-to-noise ratio is good enough even for low doses, which has allowed to reduce the integration time in the spectrometer. The presented results show the feasibility for using low cost equipment to detect/measure ionizing radiation as gamma rays are.

  8. Effect of low dose radiation on apoptosis in mouse spleen

    International Nuclear Information System (INIS)

    Chen Dong; Liu Jiamei; Chen Aijun; Liu Shuzheng

    1999-01-01

    Objective: To study the effect of whole body irradiation (WBI) with different doses of X-ray on apoptosis in mouse spleen. Methods: Time course changes and dose-effect relationship of apoptosis in mouse spleen induced by WBI were observed with transmission electron microscopy (TEM) qualitatively and TUNEL method semi-quantitatively. Results: Many typical apoptotic lymphocytes were found by TEM in mouse spleen after WBI with 2 Gy. No marked alterations of ultrastructure were found following WBI with 0.075 Gy. It was observed by TUNEL that the apoptosis of splenocytes increased after high dose radiation and decreased following low dose radiation (LDR). The dose-effect relationship of radiation-induced apoptosis showed a J-shaped curve. Conclusion: The effect of different doses of ionizing radiation on apoptosis in mouse spleen was distinct. And the decrease of apoptosis after LDR is considered a manifestation of radiation hormesis

  9. The effects of chronic low dose irradiation on drosophila melanogaster

    International Nuclear Information System (INIS)

    Zajnullin, V.G.; Moskalev, A.A.; Shaposhnikov, M.V.; Yuraneva, I.N.; Taskaev, A.I.

    2001-01-01

    It was investigated the influence of the chronic gamma-irradiation in the dose rate of 0.17 cGy/h on the rate of genetic variability and on the life-span in the laboratory strains of Drosophila melanogaster with genotypic distinguishes in mobile genetic elements and defects in the DNA repair processes. It is shown that the radiation-induced alteration of the traits under study depends from genotype of investigated strains. In the different strains we have observed an increase as well as a decrease of the mutation rate and life-span. Also it was established that irradiation leads to the frequencies of the GD-sterility and mutability of the snw and h(w+) in the P-M and H-E dysgenic crosses. The obtained results suggest that mobile genetic elements play an important role in the forming of genetic effects in response to low dose irradiation. (author)

  10. Genetic effects of low-dose irradiation in Drosophila Melanogaster

    International Nuclear Information System (INIS)

    Zajnulin, V.G.; Shaposhnikov, M.V.; Yuraneva, I.N.

    2000-01-01

    Influence of chronic γ-irradiation at the dose rate of 0.17 cGy/h on the rate of genetic variability in the laboratory strains of Drosophila Melanogaster with genotypic distinguishes by families of mobile genetic elements and of systems of hybrid disgenesis and also violations in reparation processes control mechanisms. It was shown that the rates of induction of recessive lethal mutations depended on genotype of investigated strains. In the different strains an increase as well as a decrease of the mutation rate were observed. Also in was established that irradiation leads to the increase in frequencies of the gonads sterility and mutability of the sn w and h(w + ) in the P-M and H-E dysgenic crosses. Obtained results suggest that mobile genetic elements play an important role in the forming of genetic effects in response to low dose irradiation [ru

  11. Low dose preoperative radiotherapy for carcinoma of the oesophagus

    International Nuclear Information System (INIS)

    Arnott, S.J.; Duncan, W.; Kerr, G.R.; Jack, W.J.L.; Mackillop, W.J.; Walbaum, P.R.; Cameron, E.

    1992-01-01

    Patients (176) with potentially operable squamous cell carcinoma or adenocarcinoma of middle or lower thirds of oesophagus were randomly assigned to preoperative radiotherapy or surgery alone. Patients assigned to the radiotherapy arm received 20 Gy in 10 treatments over 2 weeks, using parallel opposed 4 MV beams. The preoperative radiotherapy was not associated with any significant acute morbidity or any increase in operative complications. The median survival of the overall group of 176 patients was 8 moths, and the 5-year survival was 13%. There was no significant difference in the survival of the 90 patients who received preoperative radiotherapy and the 86 who were managed by surgery alone. Proportional hazards analysis identified lymph node involvement, high tumor grade and male sex as significant adverse prognostic features, but the treatment option assigned had no prognostic significance. It was concluded that low dose preoperative radiotherapy offered no advantage over surgery alone. (author). 9 refs.; 3 figs.; 6 tabs

  12. High and low dose-rate brachytherapy for cervical carcinoma

    International Nuclear Information System (INIS)

    Orton, C.G.

    1998-01-01

    For the brachytherapy component of the r[iation treatment of cervical carcinoma, high dose rate (HDR) is slowly replacing conventional low dose rate (LDR) due primarily to r[iation safety and other physical benefits attributed to the HDR modality. Many r[iation oncologists are reluctant to make this change because of perceived r[iobiological dis[vantages of HDR. However, in clinical practice HDR appears to be as effective as LDR but with a lower risk of late complications, as demonstrated by one randomized clinical trial and two comprehensive literature and practice surveys. The reason for this appears to be that the r[iobiological dis[vantages of HDR are outweighed by the physical [vantages. (orig.)

  13. Lung cancer screening with low-dose CT

    International Nuclear Information System (INIS)

    Diederich, S.; Wormanns, D.; Heindel, W.

    2003-01-01

    Screening for lung cancer is hoped to reduce mortality from this common tumour, which is characterised by a dismal overall survival, relatively well defined risk groups (mainly heavy cigarette smokers and workers exposed to asbestos) and a lack of early symptoms. In the past studies using sputum cytology and chest radiography have failed to demonstrate any reduction in lung cancer mortality through screening. One of the reasons is probably the relatively poor sensitivity of both these tests in early tumours. Low radiation dose computed tomography (CT) has been shown to have a much higher sensitivity for small pulmonary nodules, which are believed to be the most common presentation of early lung cancer. As, however, small pulmonary nodules are common and most are not malignant, non-invasive diagnostic algorithms are required to correctly classify the detected lesions and avoid invasive procedures in benign nodules. Nodule density, size and the demonstration of growth at follow-up have been shown to be useful in this respect and may in the future be supplemented by contrast-enhanced CT and positron emission tomography. Based on these diagnostic algorithms preliminary studies of low-dose CT in heavy smokers have demonstrated a high proportion of asymptomatic, early, resectable cancers with good survival. As, however, several biases could explain these findings in the absence of the ultimate goal of cancer screening, i.e. mortality reduction, most researchers believe that randomised controlled trials including several 10000 subjects are required to demonstrate a possible mortality reduction. Only then general recommendations to screen individuals at risk of lung cancer with low-dose CT should be made. It can be hoped that international cooperation will succeed in providing results as early as possible

  14. Low dose radiation enhances the Locomotor activity of D. melanogaster

    Energy Technology Data Exchange (ETDEWEB)

    Seong, Ki Moon; Lee, Buyng Sub; Nam Seon Young; Kim, Ji Young; Yang, Kwang Hee; Choi, Tae In; Kim, Cha Soon [Radiation Effect Research Team, Radiation Health Research Institute, Korea Hydro and Nuclear Power Co., Ltd., Gyeongju (Korea, Republic of)

    2013-04-15

    Mild stresses at low level including radiation can induce the beneficial effects in many vertebrate and invertebrate species. However, a large amount of studies in radiation biology have focused on the detrimental effects of high dose radiation (HDR) such as the increased incidence of cancers and developmental diseases. Low dose radiation (LDR) induces biologically favorable effects in diverse fields, for example, cancer development, genomic instability, immune response, and longevity. Our previous data indicated that LDR promotes cells proliferation of which degree is not much but significant, and microarray data explained that LDR irradiated fruit flies showing the augmented immunity significantly changed the program for gene expression of many genes in Gene Ontology (GO) categories related to metabolic process. Metabolic process in development one of major contributors in organism growth, interbreeding, motility, and aging. Therefore, it is valuable to examine whether LDR change the physiological parameters related to metabolism, and how LDR regulates the metabolism in D. melanogaster. In this study, to investigate that LDR influences change of the metabolism, a representative parameter, locomotor activity. In addition, the activation of several cellular signal molecules was determined to investigate the specific molecular mechanism of LDR effects on the metabolism. We explored whether ionizing radiation affects the motility activity. We performed the RING assays to evaluate the locomotor activity, a representative parameter presenting motility of fruit flies. HDR dramatically decreased the motor activity of irradiated flies. Surprisingly, the irradiated flies at low dose radiation in both acute and chronic showed the significantly increased locomotor activity, compared to non-irradiated flies. Irradiation would induce change of the several signal pathways for flies to respond to it. The activation of some proteins involved in the cells proliferation and stress

  15. Varicose Vein Stripping Under Low-Dose Spinal Anaesthesia

    Directory of Open Access Journals (Sweden)

    Nalan Muhammedoğlu

    2014-03-01

    Full Text Available Aim: Spinal anesthesia is frequently used for procedures involving the lower limbs. Compared with general anesthesia, low-dose spinal anesthesia is a cost-effective method and has advantages such as avoiding hypotension, longer duration of anesthesia and increased length of hospitalization. The aim of this trial was to compare two different low-dose bupivacaine drug regimens. Methods: Sixty unpremedicated patients were randomly allocated into two groups (n=30. There were no differences between the groups in age, weight, the American Society of Anesthesiologists (ASA physical status classification, gender, and duration of surgery. We performed spinal anesthesia at the L3-4 interspace with the patient in the lateral decubitus position. We administered 6.5 mg (group 1 and 8 mg (group 2 0.5% heavy bupivacaine into the subarachnoid space. We positioned the patient laterally to the operation side for 15 minutes, then, turned to supine position. Motor and sensory block was assessed by the Bromage scale and pinprick test. Results: There were significant differences between the two groups in duration of motor block, but no significant differences in hemodynamic response to spinal anesthesia. None of the patients had intraoperative pain. Five patients in group 1 and 2 patients in group 2 had urinary retention. Conclusion: Our observations suggest that 6.5 mg heavy bupivacaine is efficient and suitable for unilateral varicose veins stripping operation. (The Me­di­cal Bul­le­tin of Ha­se­ki 2014; 52: 25-8

  16. Cardiovascular risks associated with low dose ionizing particle radiation.

    Directory of Open Access Journals (Sweden)

    Xinhua Yan

    Full Text Available Previous epidemiologic data demonstrate that cardiovascular (CV morbidity and mortality may occur decades after ionizing radiation exposure. With increased use of proton and carbon ion radiotherapy and concerns about space radiation exposures to astronauts on future long-duration exploration-type missions, the long-term effects and risks of low-dose charged particle irradiation on the CV system must be better appreciated. Here we report on the long-term effects of whole-body proton ((1H; 0.5 Gy, 1 GeV and iron ion ((56Fe; 0.15 Gy, 1GeV/nucleon irradiation with and without an acute myocardial ischemia (AMI event in mice. We show that cardiac function of proton-irradiated mice initially improves at 1 month but declines by 10 months post-irradiation. In AMI-induced mice, prior proton irradiation improved cardiac function restoration and enhanced cardiac remodeling. This was associated with increased pro-survival gene expression in cardiac tissues. In contrast, cardiac function was significantly declined in (56Fe ion-irradiated mice at 1 and 3 months but recovered at 10 months. In addition, (56Fe ion-irradiation led to poorer cardiac function and more adverse remodeling in AMI-induced mice, and was associated with decreased angiogenesis and pro-survival factors in cardiac tissues at any time point examined up to 10 months. This is the first study reporting CV effects following low dose proton and iron ion irradiation during normal aging and post-AMI. Understanding the biological effects of charged particle radiation qualities on the CV system is necessary both for the mitigation of space exploration CV risks and for understanding of long-term CV effects following charged particle radiotherapy.

  17. Clinical application of low-dose spiral CT for orthodontics

    International Nuclear Information System (INIS)

    Xie Na; Gan Yungen; Shu Huang; Lin FeiFei; Li Zhiyong; Sun Jie

    2009-01-01

    Objective: To determine the effect of reducing the value of mA or kV on the image quality and the radiation dose of the patients undergoing low-dose spiral CT for orthodontics. Methods: Thirty patients were divided into three groups, each group has 10 patients. They were group 1 (80 kV and 200 mA), group 2 (120 kV and 80 mA), group 3 (120 kV and 200 mA) The volume CT dose index (CTDI) was recorded and the average dose-length produce (DLP) was calculated in three groups,respectively. Image quality of three groups were compared and scored by two radiologists, and the results were statistically analysed. Results: The CTDI and DLP of 80 kV group (group 2) were 8.7 mGy and (36.80 ± 3.60) mGy · cm, respectively, those of 80 mA group (group 3) were 19.6 mGy and (82.14 ± 7.18) mGy · cm, respectively, and those of conventional-dose group (group 1) were 19.6 mGy and (82.14 ± 7.18) mGy · cm, respectively. There was no significant difference among three groups in diagnostic image quality. Conclusions: Low-dose spiral CT for orthodontics, especially the low-kV scan, may decrease the radiation exposure and guarantee the image quality. (authors)

  18. Low-Dose Radiation Cataract and Genetic Determinants of Radiosensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Kleiman, Norman Jay [Columbia University

    2013-11-30

    The lens of the eye is one of the most radiosensitive tissues in the body. Ocular ionizing radiation exposure results in characteristic, dose related, progressive lens changes leading to cataract formation. While initial, early stages of lens opacification may not cause visual disability, the severity of such changes progressively increases with dose until vision is impaired and cataract extraction surgery may be required. Because of the transparency of the eye, radiation induced lens changes can easily be followed non-invasively over time. Thus, the lens provides a unique model system in which to study the effects of low dose ionizing radiation exposure in a complex, highly organized tissue. Despite this observation, considerable uncertainties remain surrounding the relationship between dose and risk of developing radiation cataract. For example, a growing number of human epidemiological findings suggest significant risk among various groups of occupationally and accidentally exposed individuals and confidence intervals that include zero dose. Nevertheless, questions remain concerning the relationship between lens opacities, visual disability, clinical cataract, threshold dose and/or the role of genetics in determining radiosensitivity. Experimentally, the response of the rodent eye to radiation is quite similar to that in humans and thus animal studies are well suited to examine the relationship between radiation exposure, genetic determinants of radiosensitivity and cataractogenesis. The current work has expanded our knowledge of the low-dose effects of X-irradiation or high-LET heavy ion exposure on timing and progression of radiation cataract and has provided new information on the genetic, molecular, biochemical and cell biological features which contribute to this pathology. Furthermore, findings have indicated that single and/or multiple haploinsufficiency for various genes involved in DNA repair and cell cycle checkpoint control, such as Atm, Brca1 or Rad9

  19. Metal Hypersensitivity in Orthodontic Patients

    Directory of Open Access Journals (Sweden)

    Sandhya Maheshwari Sanjeev K

    2015-06-01

    Full Text Available Orthodontic treatment of individuals with metal hypersensitivity is a matter of concern for the orthodontist. Orthodontic appliances contain metals like Nickel, Cobalt and Chromium etc. Metals may cause allergic reactions and are known as allergens. Reaction to these metals is due to biodegradation of metals in the oral cavity. This may lead to the formation of corrosion products and their exposure to the patient. Nickel is the most common metal to cause hypersensitivity reaction. Chromium ranks second among the metals, known to trigger allergic reactions. The adverse biological reactions to these metals may include hypersensitivity, dermatitis and asthma. In addition, a significant carcinogenic and mutagenic potential has been demonstrated. The orthodontist must be familiar with the best possible alternative treatment modalities to provide the safest, most effective care possible in these cases. The present article focuses on the issue of metal hypersensitivity and its management in orthodontic

  20. The Contribution of Tissue Level Organization to Genomic Stability Following Low Dose/Low Dose Rate Gamma and Proton Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Cheryl G. Burrell, Ph.D.

    2012-05-14

    The formation of functional tissue units is necessary in maintaining homeostasis within living systems, with individual cells contributing to these functional units through their three-dimensional organization with integrin and adhesion proteins to form a complex extra-cellular matrix (ECM). This is of particular importance in those tissues susceptible to radiation-induced tumor formation, such as epithelial glands. The assembly of epithelial cells of the thyroid is critical to their normal receipt of, and response to, incoming signals. Traditional tissue culture and live animals present significant challenges to radiation exposure and continuous sampling, however, the production of bioreactor-engineered tissues aims to bridge this gap by improve capabilities in continuous sampling from the same functional tissue, thereby increasing the ability to extrapolate changes induced by radiation to animals and humans in vivo. Our study proposes that the level of tissue organization will affect the induction and persistence of low dose radiation-induced genomic instability. Rat thyroid cells, grown in vitro as 3D tissue analogs in bioreactors and as 2D flask grown cultures were exposed to acute low dose (1, 5, 10 and 200 cGy) gamma rays. To assess immediate (6 hours) and delayed (up to 30 days) responses post-irradiation, various biological endpoints were studied including cytogenetic analyses, apoptosis analysis and cell viability/cytotoxicity analyses. Data assessing caspase 3/7 activity levels show that, this activity varies with time post radiation and that, overall, 3D cultures display more genomic instability (as shown by the lower levels of apoptosis over time) when compared to the 2D cultures. Variation in cell viability levels were only observed at the intermediate and late time points post radiation. Extensive analysis of chromosomal aberrations will give further insight on the whether the level of tissue organization influences genomic instability patterns after

  1. Mechanisms and biological importance of photon-induced bystander responses. Do they have an impact on low-dose radiation responses

    International Nuclear Information System (INIS)

    Tomita, Masanori; Maeda, Munetoshi

    2015-01-01

    Elucidating the biological effect of low linear energy transfer (LET), low-dose and/or low-dose-rate ionizing radiation is essential in ensuring radiation safety. Over the past two decades, non-targeted effects, which are not only a direct consequence of radiation-induced initial lesions produced in cellular DNA but also of intra- and inter-cellular communications involving both targeted and non-targeted cells, have been reported and are currently defining a new paradigm in radiation biology. These effects include radiation-induced adaptive response, low-dose hypersensitivity, genomic instability, and radiation-induced bystander response (RIBR). RIBR is generally defined as a cellular response that is induced in non-irradiated cells that receive bystander signals from directly irradiated cells. RIBR could thus play an important biological role in low-dose irradiation conditions. However, this suggestion was mainly based on findings obtained using high-LET charged-particle radiations. The human population (especially the Japanese, who are exposed to lower doses of radon than the world average) is more frequently exposed to low-LET photons (X-rays or γ-rays) than to high-LET charged-particle radiation on a daily basis. There are currently a growing number of reports describing a distinguishing feature between photon-induced bystander response and high-LET RIBR. In particular, photon-induced by-stander response is strongly influenced by irradiation dose, the irradiated region of the targeted cells, and p53 status. The present review focuses on the photon-induced bystander response, and discusses its impact on the low-dose radiation effect. (author)

  2. Low doses effects and gamma radiations low dose rates; Les effets des faibles doses et des faibles debits de doses de rayons gamma

    Energy Technology Data Exchange (ETDEWEB)

    Averbeck, D [Institut Curie, CNRS UMR 2027, 75 - Paris (France)

    1999-07-01

    This expose wishes for bringing some definitions and base facts relative to the problematics of low doses effects and low dose rates effects. It shows some already used methods and some actual experimental approaches by focusing on the effects of ionizing radiations with a low linear energy transfer. (N.C.)

  3. Low doses effects of ionizing radiation on Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Durand, J.; Broock, M. van; Gillette, V.H.

    2000-01-01

    The exposure of living cells to low doses of ionizing radiation induce in response the activation of cellular protection mechanisms against subsequent larger doses of radiation. This cellular adaptive response may vary depending on radiation intensity and time of exposure, and also on the testing probes used whether they were mammalian cells, yeast, bacteria and other organisms or cell types. The mechanisms involved are the genome activation, followed by DNA repair enzymes synthesis. Due to the prompt cell response, the cell cycle can be delayed, and the secondary detoxification of free radicals and/or activation of membrane bound receptors may proceed. All these phenomena are submitted to intense scientific research nowadays, and their elucidation will depend on the complexity of the organism under study. In the present work, the effects of low doses of ionizing radiation (gamma rays) over a suspension of the yeast Saccharomyces cerevisiae (Baker's yeast) was studied, mainly in respect to survival rate and radio-adaptive response. At first, the yeast surviving curve was assessed towards increasing doses, and an estimation of Lethal Dose 50 (LD50) was made. The irradiation tests were performed at LINAC (electrons Linear Accelerator) where electron energy reached approximately 2.65 MeV, and gamma-radiation was produced for bremsstrahlung process over an aluminium screen target. A series of experiments of conditioning doses was performed and an increment surviving fraction was observed when the dose was 2.3 Gy and a interval time between this and a higher dose (challenging dose) of 27 Gy was 90 minutes. A value of 58 ± 4 Gy was estimated for LD50, at a dose rate of 0.44 ± 0.03 Gy/min These quantities must be optimized. Besides data obtained over yeast survival, an unusual increasing amount of tiny yeast colonies appeared on the agar plates after incubation, and this number increased as increasing the time exposure. Preliminary results indicate these colonies as

  4. Thalidomide increases human keratinocyte migration and proliferation.

    Science.gov (United States)

    Nasca, M R; O'Toole, E A; Palicharla, P; West, D P; Woodley, D T

    1999-11-01

    Thalidomide is reported to have therapeutic utility in the treatment of pyoderma gangrenosum, Behçet's disease, aphthous ulcers, and skin wounds. We investigated the effect of thalidomide on human keratinocyte proliferation and migration, two early and critical events in the re-epithelialization of skin wounds. Thalidomide at concentrations less than 1 microM did not affect keratinocyte viability. Using a thymidine incorporation assay, we found that thalidomide, at therapeutic concentrations, induced more than a 2. 5-fold increase in the proliferative potential of the cells. Keratinocyte migration was assessed by two independent motility assays: a colloidal gold assay and an in vitro scratch assay. At optimal concentrations, thalidomide increased keratinocyte migration on a collagen matrix more than 2-fold in the colloidal gold assay and more than 3-fold in the scratch assay over control. Although pro-migratory, thalidomide did not alter the level of metalloproteinase-9 secreted into culture medium. Thalidomide did, however, induce a 2-4-fold increase in keratinocyte-derived interleukin-8, a pro-migratory cellular autocrine factor. Human keratinocyte migration and proliferation are essential for re-epithelialization of skin wounds. Interleukin-8 increases human keratinocyte migration and proliferation and is chemotactic for keratinocytes. Therefore, thalidomide may modulate keratinocyte proliferation and motility by a chemokine-dependent pathway.

  5. Low-dose radiation suppresses Pokemon expression under hypoxic conditions.

    Science.gov (United States)

    Kim, Seung-Whan; Yu, Kweon; Shin, Kee-Sun; Kwon, Kisang; Hwang, Tae-Sik; Kwon, O-Yu

    2014-01-01

    Our previous data demonstrated that CoCl2-induced hypoxia controls endoplasmic reticulum (ER) stress-associated and other intracellular factors. One of them, the transcription factor Pokemon, was differentially regulated by low-dose radiation (LDR). There are limited data regarding how this transcription factor is involved in expression of the unfolded protein response (UPR) under hypoxic conditions. The purpose of this study was to obtain clues on how Pokemon is involved in the UPR. Pokemon was selected as a differentially expressed gene under hypoxic conditions; however, its regulation was clearly repressed by LDR. It was also demonstrated that both expression of ER chaperones and ER stress sensors were affected by hypoxic conditions, and the same results were obtained when cells in which Pokemon was up- or down-regulated were used. The current state of UPR and LDR research associated with the Pokemon pathway offers an important opportunity to understand the oncogenesis, senescence, and differentiation of cells, as well as to facilitate introduction of new therapeutic radiopharmaceuticals.

  6. Effect of low doses gamma irradiation of cotton seeds

    International Nuclear Information System (INIS)

    Al-Oudat, M.; Khalifa, Kh.

    1996-01-01

    Field experiments and then large scale application of irradiated cotton seeds (C.V. Aleppo-40) were carried out during three seasons (1986, 1987 and 1988) for field experiment at ACSAD Station in Dier-Ezzor and 1988, 1989 and 1990 for large scale application at Euphrate's Basin, Al-Ghab and Salamia, farmers farms. The above areas were selected as they represent major cotton production areas in Syria. The aims of the experiments were to study the effect of low doses of gamma irradiation 0, 5, 10, 20, 30, 40 and 50 Gy on cotton yield and to look for the optimum dose of gamma irradiation to obtain best results. The results show that, there were positive effect (P<0.95) for doses 5-30 Gy in increasing cotton yield. The highest increase was at dose of 10 Gy. which as 19.5% higher than control. For the large scale application using 10 Gy the increase in cotton yield varied from 10-39% compared to control. (author). 11 refs., 6 figs

  7. Sensitivity to low-dose radiation in radiosensitive ''wasted'' mice

    International Nuclear Information System (INIS)

    Paunesku, T.; Protic, M.; Woloschak, G. E.

    1999-01-01

    Mice homozygous for the autosomal recessive wasted mutation (wst/wst) have abnormalities in T-lymphocytes and in the anterior motor neuron cells of the spinal cord, leading to sensitivity to low doses of ionizing radiation, hind limb paralysis, and immunodeficiency. This defect results in a failure to gain weight by 20 days and death at 28 days of age. The wasted mutation (previously mapped to mouse chromosome 2) is shown to be a 3-bp deletion in a T-cell-specific (and perhaps motor-neuron-specific) regulatory region (promoter) of the proliferating cell nuclear antigen (PCNA) gene on mouse chromosome 2. A regulatory element is also shown to be important in PCNA expression in T-lymphocytes and motor neuron cells afflicted by the 3-bp deletion in the PCNA promoter. The model is as follows: Absence of PCNA expression in the thymuses (and motor neurons) of wasted mice causes cellular apoptosis; this absence of expression is mediated by a positive transactor that can bind to the wild-type but not the wasted mutant PCNA promoter; the bound protein induces late expression of PCNA in T-lymphocytes and prevents onset of radiation sensitivity in the cells

  8. Medical effects of low doses of ionising radiation

    International Nuclear Information System (INIS)

    Coggle, J.E.

    1990-01-01

    Ionising radiation is genotoxic and causes biological effects via a chain of events involving DNA strand breaks and 'multiply damaged sites' as critical lesions that lead to cell death. The acute health effects of radiation after doses of a few gray, are due to such cell death and consequent disturbance of cell population kinetics. Because of cellular repair and repopulation there is generally a threshold dose of about 1-2 Gy below which such severe effects are not inducible. However, more subtle, sub-lethal mutational DNA damage in somatic cells of the body and the germ cells of the ovary and testis cause the two major low dose health risks -cancer induction and genetic (heritable) effects. This paper discusses some of the epidemiological and experimental evidence regarding radiation genetic effects, carcinogenesis and CNS teratogenesis. It concludes that current risk estimates imply that about 3% of all cancers; 1% of genetic disorders and between 0% and 0.3% of severe mental subnormality in the UK is attributable to the ubiquitous background radiation. The health risks associated with the medical uses of radiation are smaller, whilst the nuclear industry causes perhaps 1% of the health detriment attributable to background doses. (author)

  9. Carcinogenesis in mice after low doses and dose rates

    International Nuclear Information System (INIS)

    Ullrich, R.L.

    1979-01-01

    The results from the experimental systems reported here indicate that the dose-response curves for tumor induction in various tissues cannot be described by a single model. Furthermore, although the understanding of the mechanisms involved in different systems is incomplete, it is clear that very different mechanisms for induction are involved. For some tumors the mechanism of carcinogenesis may be mainly a result of direct effects on the target cell, perhaps involving one or more mutations. While induction may occur, in many instances, through such direct effects, the eventual expression of the tumor can be influenced by a variety of host factors including endocrine status, competence of the immune system, and kinetics of target and interacting cell populations. In other tumors, indirect effects may play a major role in the initiation or expression of tumors. Some of the hormone-modulated tumors would fall into this class. Despite the complexities of the experimental systems and the lack of understanding of the types of mechanisms involved, in nearly every example the tumorigenic effectiveness per rad of low-LET radiation tends to decrease with decreasing dose rate. For some tumor types the differences may be small or may appear only with very low dose rates, while for others the dose-rate effects may be large

  10. Fully automated gynecomastia quantification from low-dose chest CT

    Science.gov (United States)

    Liu, Shuang; Sonnenblick, Emily B.; Azour, Lea; Yankelevitz, David F.; Henschke, Claudia I.; Reeves, Anthony P.

    2018-02-01

    Gynecomastia is characterized by the enlargement of male breasts, which is a common and sometimes distressing condition found in over half of adult men over the age of 44. Although the majority of gynecomastia is physiologic or idiopathic, its occurrence may also associate with an extensive variety of underlying systemic disease or drug toxicity. With the recent large-scale implementation of annual lung cancer screening using low-dose chest CT (LDCT), gynecomastia is believed to be a frequent incidental finding on LDCT. A fully automated system for gynecomastia quantification from LDCT is presented in this paper. The whole breast region is first segmented using an anatomyorientated approach based on the propagation of pectoral muscle fronts in the vertical direction. The subareolar region is then localized, and the fibroglandular tissue within it is measured for the assessment of gynecomastia. The presented system was validated using 454 breast regions from non-contrast LDCT scans of 227 adult men. The ground truth was established by an experienced radiologist by classifying each breast into one of the five categorical scores. The automated measurements have been demonstrated to achieve promising performance for the gynecomastia diagnosis with the AUC of 0.86 for the ROC curve and have statistically significant Spearman correlation r=0.70 (p early detection as well as the treatment of both gynecomastia and the underlying medical problems, if any, that cause gynecomastia.

  11. Low dose radiation prevents doxorubicin-induced cardiotoxicity.

    Science.gov (United States)

    Jiang, Xin; Hong, Yaqiong; Zhao, Di; Meng, Xinxin; Zhao, Lijing; Du, Yanwei; Wang, Zan; Zheng, Yan; Cai, Lu; Jiang, Hongyu

    2018-01-02

    This study aimed to develop a novel and non-invasive approach, low-dose radiation (LDR, 75 mGy X-rays), to prevent doxorubicin (DOX)-induced cardiotoxicity. BALB/c mice were randomly divided into five groups, Control, LDR (a single exposure), Sham (treated same as LDR group except for irradiation), DOX (a single intraperitoneal injection of DOX at 7.5 mg/kg), and LDR/DOX (received LDR and 72 h later received DOX). Electrocardiogram analysis displayed several kinds of abnormal ECG profiles in DOX-treated mice, but less in LDR/DOX group. Cardiotoxicity indices included histopathological changes, oxidative stress markers, and measurements of mitochondrial membrane permeability. Pretreatment of DOX group with LDR reduced oxidative damages (reactive oxygen species formation, protein nitration, and lipid peroxidation) and increased the activities of antioxidants (superoxide dismutase and glutathione peroxidase) in the heart of LDR/DOX mice compared to DOX mice. Pretreatment of DOX-treated mice with LDR also decreased DOX-induced cardiac cell apoptosis (TUNEL staining and cleaved caspase-3) and mitochondrial apoptotic pathway (increased p53, Bax, and caspase-9 expression and decreased Bcl2 expression and ΔΨm dissipation). These results suggest that LDR could induce adaptation of the heart to DOX-induced toxicity. Cardiac protection by LDR may attribute to attenuate DOX-induced cell death via suppressing mitochondrial-dependent oxidative stress and apoptosis signaling.

  12. Risk at Low Doses: Scientific knowledge, uncertainties and management

    International Nuclear Information System (INIS)

    Giusssani, A.; Ballarini, F.; Ottolenghi, A.

    2002-01-01

    Most of the applications of ionizing radiation in the medical field, for the exposed workers as well as the majority of patients undergoing diagnostic examinations, can be seen as low situations. Epidemiological information is however available for dose and dose rates higher than the values typical of most medical situation. Main source of information is the Life Span Study (LSS) of Japanese. A-bomb survivors, supplemented by studies of selected groups of exposed workers (uranium miners, radium painters) or radiotherapy patients with a detailed follow-up history. All of these group studies, however, suffer from one or more of the following limitations: - lack of adequate dosimetry - lack of a reliable control group for the necessary comparison - influence of concomitant factors (not always easy to find out) - influence of social conditions. In addition exposed study populations are different than the population of patients for which the risk estimates are needed in the medical situation. Recent studies aimed to evaluate the available data on the cohorts of the inhabitants of the Techa river settlements as well as of the workers of the Mayak nuclear facilities may provide in the future useful information on large populations chronically exposed to relatively low doses. (Author)

  13. International Conference on Low Doses of Ionising Radiation

    International Nuclear Information System (INIS)

    McEwan, A.C.

    1998-01-01

    Is there a threshold? and is a little radiation good for you? were two questions raised at the International Conference on Low Doses of Ionising Radiation : Biological Effects and Regulatory Control, jointly organised by the IAEA and WHO, and convened in Seville, Spain, over 17-21 November 1997. The answer to both these questions appears to be 'Maybe', but the answer has no present implications for radiation protection practice and regulation. The conference which had over 500 participants from 65 countries, was organised around ten fora which explored basic molecular mechanisms of radiation effects, through to radiation protection principles and implementation in practices and interventions. Each forum was introduced by an overview presentation by an invited keynote speaker. Brief presentations of a few of the proffered papers followed, and then open discussion. There was opportunity for all proffered papers to be presented as posters. The fora, which occupied 3 full days, were preceded by reports on biological effects of radiation from international orgnaisations, and on related international conferences held in the recent past. The fora were followed by round table presentations of regulatory control and scientiFic research, and a summary session drawing together conclusions on the topic areas of the conference. (author)

  14. Bayesian approach in MN low dose of radiation counting

    International Nuclear Information System (INIS)

    Serna Berna, A.; Alcaraz, M.; Acevedo, C.; Navarro, J. L.; Alcanzar, M. D.; Canteras, M.

    2006-01-01

    The Micronucleus assay in lymphocytes is a well established technique for the assessment of genetic damage induced by ionizing radiation. Due to the presence of a natural background of MN the net MN is obtained by subtracting this value to the gross value. When very low doses of radiation are given the induced MN is close even lower than the predetermined background value. Furthermore, the damage distribution induced by the radiation follows a Poisson probability distribution. These two facts pose a difficult task to obtain the net counting rate in the exposed situations. It is possible to overcome this problem using a bayesian approach, in which the selection of a priori distributions for the background and net counting rate plays an important role. In the present work we make a detailed analysed using bayesian theory to infer the net counting rate in two different situations: a) when the background is known for an individual sample, using exact value value for the background and Jeffreys prior for the net counting rate, and b) when the background is not known and we make use of a population background distribution as background prior function and constant prior for the net counting rate. (Author)

  15. Dynamic low dose I-123-iodophenylpentadecanoic acid metabolic cardiac imaging

    International Nuclear Information System (INIS)

    Murray, G.L.; Magill, H.L.; Schad, N.C.

    1993-01-01

    Recognition of stunned and hibernating myocardium is essential in this era of cardiac revascularization. Positron emission tomography (PET) accurately identifies viability but is costly and unavailable to most patients. Dynamic low dose I-123-iodophenylpentadecanoic acid (IPPA) metabolic cardiac imaging is a potentially cost-effective alternative to PET. Using transmural myocardial biopsies obtained during coronary bypass surgery as the viability gold standard, resting IPPA imaging agreed with 39/43 (91%) biopsies, with a sensitivity for viability of 33/36(92%) and a specificity of 6/7 (86%) in patients with severe ischemic cardiomyopathy. Eighty percent of IPPA viable, infarcted segments improved wall motion postoperatively. Furthermore, when compared to reinjection thallium (SPECT-Tl) scans after myocardial infarction, there was IPPA-Tl concordance in 27/35 (77%)(Kappa=0.536, p=0.0003). Similar to PET, IPPA demonstrated more viability than SPECT-Tl, 26/35 (74%) vs. 18/35 (51%)(p=0.047). Finally, when compared to transvenous endomyocardial biopsy for detecting rejection following cardiac transplantation, IPPA sensitivity for ≥Grade II rejection was 100%, and IPPA screening assessment for the necessity of biopsy could result in a 31% cost-savings. Therefore, IPPA metabolic cardiac imaging is a safe, inexpensive technique with a promising future. (author)

  16. Low-dose caffeine physical dependence in humans.

    Science.gov (United States)

    Griffiths, R R; Evans, S M; Heishman, S J; Preston, K L; Sannerud, C A; Wolf, B; Woodson, P P

    1990-12-01

    This study investigated the effects of terminating low dose levels of caffeine (100 mg/day) in 7 normal humans. Substitution of placebo capsules for caffeine capsules occurred under double-blind conditions while subjects rated various dimensions of their mood and behavior. In the first phase of the study, substitution of placebo for 12 consecutive days resulted in an orderly withdrawal syndrome in 4 subjects which peaked on days 1 or 2 and progressively decreased toward prewithdrawal levels over about 1 week. Data from the remaining three subjects provided no evidence of withdrawal. In the second phase of the study, the generality of the withdrawal effect was examined by repeatedly substituting placebo for 100 mg/day of caffeine for 1-day periods separated by an average of 9 days. Despite differences within and across subjects with respect to the presence, nature and magnitude of symptoms, each of the seven subjects demonstrated a statistically significant withdrawal effect. Although the phenomenon of caffeine withdrawal has been described previously, the present report documents that the incidence of caffeine withdrawal is higher (100% of subjects), the daily dose level at which withdrawal occurs is lower (roughly equivalent to the amount of caffeine in a single cup of strong brewed coffee or 3 cans of caffeinated soft drink) and the range of symptoms experienced is broader (including headache, fatigue and other dysphoric mood changes, muscle pain/stiffness, flu-like feelings, nausea/vomiting and craving for caffeine) than heretofore recognized.

  17. Thermal stability of low dose Ga+ ion irradiated spin valves

    International Nuclear Information System (INIS)

    Qi Xianjin; Wang Yingang; Zhou Guanghong; Li Ziquan

    2009-01-01

    The thermal stability of low dose Ga + ion irradiated spin valves has been investigated and compared with that of the as-prepared ones. The dependences of exchange field, measured using vibrating sample magnetometer at room temperature, on magnetic field sweep rate and time spent at negative saturation of the pinned ferromagnetic layer, and training effect were explored. The training effect is observed on both the irradiated spin valves and the as-prepared ones. The magnetic field sweep rate dependence of the exchange bias field of the irradiated spin valves is nearly the same as that of the as-prepared ones. For the as-prepared structure thermal activation has been observed, which showed that holding the irradiated structure at negative saturation of the pinned ferromagnetic layer for up to 28 hours results in no change in the exchange field. The results indicate that the thermal stability of the ion irradiated spin valves is the same as or even better than the as-prepared ones.

  18. Biological effects of low doses of ionizing radiation

    International Nuclear Information System (INIS)

    Gonzalez, A.J.

    1994-01-01

    Few weeks ago, when the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) submitted to the U.N. General Assembly the UNSCEAR 1994 report, the international community had at its disposal a broad view of the biological effects of low doses of ionizing radiation. The 1994 report (272 pages) specifically addressed the epidemiological studies of radiation carcinogenesis and the adaptive responses to radiation in cells and organisms. The report was aimed to supplement the UNSCEAR 1993 report to the U.N. General Assembly- an extensive document of 928 pages-which addressed the global levels of radiation exposing the world population, as well as some issues on the effects of ionizing radiation, including: mechanisms of radiation oncogenesis due to radiation exposure, influence of the level of dose and dose rate on stochastic effects of radiation, hereditary effects of radiation effects on the developing human brain, and the late deterministic effects in children. Those two UNSCEAR reports taken together provide an impressive overview of current knowledge on the biological effects of ionizing radiation. This article summarizes the essential issues of both reports, although it cannot cover all available information. (Author)

  19. Health Effects of Exposure to Low Dose of Radiation

    International Nuclear Information System (INIS)

    Alatas, Zubaidah

    2003-01-01

    Human beings are exposed to natural radiation from external sources include radionuclides in the earth and cosmic radiation, and by internal radiation from radionuclides, mainly uranium and thorium series, incorporated into the body. Living systems have adapted to the natural levels of radiation and radioactivity. But some industrial practices involving natural resources enhance these radionuclides to a degree that they may pose risk to humans and the environment if they are not controlled. Biological effects of ionizing radiation are the outcomes of physical and chemical processes that occur immediately after the exposure, then followed by biological process in the body. These processes will involve successive changes in the molecular, cellular, tissue and whole organism levels. Any dose of radiation, no matter how small, may produce health effects since even a single ionizing event can result in DNA damage. The damage to DNA in the nucleus is considered to be the main initiating event by which radiation causes damage to cells that results in the development of cancer and hereditary disease. It has also been indicated that cytogenetic damage can occur in cells that receive no direct radiation exposure, known as bystander effects. This paper reviews health risks of low dose radiation exposure to human body causing stochastic effects, i.e. cancer induction in somatic cells and hereditary disease in genetic cells. (author)

  20. Low dose CT perfusion in acute ischemic stroke

    International Nuclear Information System (INIS)

    Murphy, Amanda; Symons, Sean; Jakubovic, Raphael; Zhang, Liying; Aviv, Richard I.; So, Aaron; Lee, Ting-Yim

    2014-01-01

    The purpose of this investigation is to determine if CT perfusion (CTP) measurements at low doses (LD = 20 or 50 mAs) are similar to those obtained at regular doses (RD = 100 mAs), with and without the addition of adaptive statistical iterative reconstruction (ASIR). A single-center, prospective study was performed in patients with acute ischemic stroke (n = 37; 54 % male; age = 74 ± 15 years). Two CTP scans were performed on each subject: one at 100 mAs (RD) and one at either 50 or 20 mAs (LD). CTP parameters were compared between the RD and LD scans in regions of ischemia, infarction, and normal tissue. Differences were determined using a within-subjects ANOVA (p 0.05). CTP-derived CBF and CBV are not different at 50 mAs compared to 100 mAs, even without the addition of ASIR. Current CTP protocols can be modified to reduce the effective dose by 50 % without altering CTP measurements. (orig.)

  1. Low dose CT perfusion in acute ischemic stroke.

    Science.gov (United States)

    Murphy, Amanda; So, Aaron; Lee, Ting-Yim; Symons, Sean; Jakubovic, Raphael; Zhang, Liying; Aviv, Richard I

    2014-12-01

    The purpose of this investigation is to determine if CT perfusion (CTP) measurements at low doses (LD = 20 or 50 mAs) are similar to those obtained at regular doses (RD = 100 mAs), with and without the addition of adaptive statistical iterative reconstruction (ASIR). A single-center, prospective study was performed in patients with acute ischemic stroke (n = 37; 54% male; age = 74 ± 15 years). Two CTP scans were performed on each subject: one at 100 mAs (RD) and one at either 50 or 20 mAs (LD). CTP parameters were compared between the RD and LD scans in regions of ischemia, infarction, and normal tissue. Differences were determined using a within-subjects ANOVA (p test post hoc analysis (p 50 mAs, there was no significant difference between cerebral blood flow (CBF), cerebral blood volume (CBV), or time to maximum enhancement (Tmax) values for the RD and LD scans in the ischemic, infarcted, or normal contralateral regions (p LD scans for all parameters in the ischemic and normal tissue regions (p > 0.05). CTP-derived CBF and CBV are not different at 50 mAs compared to 100 mAs, even without the addition of ASIR. Current CTP protocols can be modified to reduce the effective dose by 50 % without altering CTP measurements.

  2. Low dose radiation damage effects in silicon strip detectors

    International Nuclear Information System (INIS)

    Wiącek, P.; Dąbrowski, W.

    2016-01-01

    The radiation damage effects in silicon segmented detectors caused by X-rays have become recently an important research topic driven mainly by development of new detectors for applications at the European X-ray Free Electron Laser (E-XFEL). However, radiation damage in silicon strip is observed not only after extreme doses up to 1 GGy expected at E-XFEL, but also at doses in the range of tens of Gy, to which the detectors in laboratory instruments like X-ray diffractometers or X-ray spectrometers can be exposed. In this paper we report on investigation of radiation damage effects in a custom developed silicon strip detector used in laboratory diffractometers equipped with X-ray tubes. Our results show that significant degradation of detector performance occurs at low doses, well below 200 Gy, which can be reached during normal operation of laboratory instruments. Degradation of the detector energy resolution can be explained by increasing leakage current and increasing interstrip capacitance of the sensor. Another observed effect caused by accumulation of charge trapped in the surface oxide layer is change of charge division between adjacent strips. In addition, we have observed unexpected anomalies in the annealing process.

  3. Low dose radiation damage effects in silicon strip detectors

    Science.gov (United States)

    Wiącek, P.; Dąbrowski, W.

    2016-11-01

    The radiation damage effects in silicon segmented detectors caused by X-rays have become recently an important research topic driven mainly by development of new detectors for applications at the European X-ray Free Electron Laser (E-XFEL). However, radiation damage in silicon strip is observed not only after extreme doses up to 1 GGy expected at E-XFEL, but also at doses in the range of tens of Gy, to which the detectors in laboratory instruments like X-ray diffractometers or X-ray spectrometers can be exposed. In this paper we report on investigation of radiation damage effects in a custom developed silicon strip detector used in laboratory diffractometers equipped with X-ray tubes. Our results show that significant degradation of detector performance occurs at low doses, well below 200 Gy, which can be reached during normal operation of laboratory instruments. Degradation of the detector energy resolution can be explained by increasing leakage current and increasing interstrip capacitance of the sensor. Another observed effect caused by accumulation of charge trapped in the surface oxide layer is change of charge division between adjacent strips. In addition, we have observed unexpected anomalies in the annealing process.

  4. The hyper-radiosensitivity effect of human hepatoma SMMC-7721 cells exposed to low dose γ-rays and 12C ions

    International Nuclear Information System (INIS)

    Jin Xiaodong; Li Qiang; Li Wenjian; Wang Jufang; Guo Chuanling; Hao Jifang

    2006-01-01

    Hypersensitive response of mammalian cells in cell killing to X- and γ-rays has been reported at doses below 1 Gy. The purpose of this study was to examine the low dose sensitivity of human hepatoma SMMC-7721 cells irradiated with 6 Co γ-rays and 50 MeV/u 12 C ions. Experiments using γ-rays and charged particle irradiation were performed, particularly in the low dose range from 0 to 2 Gy. The survival effect of SMMC-7721 cells was measured by means of standard clonogenic assay in conjunction with a cell sorter. The result indicates SMMC-7721 cells showed hyper-radiosensitive response at low doses and increased radio-resistance at larger single doses for the carbon ions (LET = 45.2 keV/μm) and the γ-rays. However, the HRS/IRR effect caused by high-LET irradiation is different from that by low-LET radiation. This might possibly be due to the difference in the mode of energy deposition by particle beam and low-LET irradiation

  5. Final report for project "Effects of Low-Dose Irradiation on NFkB Signaling Networks and Mitochondria"

    Energy Technology Data Exchange (ETDEWEB)

    Woloschak, Gayle E [Northwestern Univ., Evanston, IL (United States); Grdina, David [Univ. of Chicago, IL (United States); Li, Jian-Jian [Univ. of California, Davis, CA (United States)

    2017-06-12

    Low dose ionizing radiation effects are difficult to study in human population because of the numerous confounding factors such as genetic and lifestyle differences. Research in mammalian model systems and in vitro is generally used in order to overcome this difficulty. In this program project three projects have joined together to investigate effects of low doses of ionizing radiation. These are doses at and below 10 cGy of low linear energy transfer ionizing radiation such as X-ray and gamma rays. This project was focused on cellular signaling associated with nuclear factor kappa B (NFkB) and mitochondria - subcellular organelles critical for cell aging and aging-like changes induced by ionizing radiation. In addition to cells in culture this project utilized animal tissues accumulated in a radiation biology tissue archive housed at Northwestern University (http://janus.northwestern.edu/janus2/index.php). Major trust of Project 1 was to gather all of the DoE sponsored irradiated animal (mouse, rat and dog) data and tissues under one roof and investigate mitochondrial DNA changes and micro RNA changes in these samples. Through comparison of different samples we were trying to delineate mitochondrial DNA quantity alterations and micro RNA expression differences associated with different doses and dose rates of radiation. Historic animal irradiation experiments sponsored by DoE were done in several national laboratories and universities between 1950’s and 1990’s; while these experiments were closed data and tissues were released to Project 1. Project 2 used cells in culture to investigate effects that low doses or radiation have on NFκB and its target genes manganese superoxide dismutase (MnSOD) and genes involved in cell cycle: Cyclins (B1 and D1) and cyclin dependent kinases (CDKs). Project 3 used cells in culture such as “normal” human cells (breast epithelial cell line MCF10A cells and skin keratinocyte cells HK18) and mouse embryo fibroblast (mef

  6. Effect of low-dose irradiation on pregnant mouse haemopoiesis

    International Nuclear Information System (INIS)

    Weinberg, S.R.; McCarthy, E.G.; MacVittie, T.J.; Baum, S.J.

    1981-01-01

    The effects of low-dose gamma radiation to haemopoietic progenitor cell compartments of the marrow and spleen of virgin female mice and pregnant mice were studied. Microplasma clot cultures were used to assess burst-forming uniterythroid (BFU-E) and colony-forming unit-erythroid (CFU-E) activity, and double-layer agar cultures were established to evaluate granulocyte-macrophage colony-forming cell (GM-CFC) and macrophage colony-forming cell (M-CFC). The apparent shift in maternal erythropoiesis from the bone marrow to the enlarged spleen was reflected by an increase in CFU-E and BFU-E per spleen and a concomitant decrease in CFU-E and BFU-E per femur. Whereas maternal GM-CFC values per femur increased 36%, maternal GM-CFC per spleen increased by 172% compared to virgin values. Total-body irradiation to the day-10.5 pregnant mouse caused a further suppression of day-14.5 medullary erythropoiesis (i.e. decreased CFU-E values) compared to the virgin female mouse. An ability of the maternal spleen to support further compensatory erythropoiesis following increasing doses of radiation was demonstrated. Four days after 1.0 Gy exposure, maternal values for GM-CFC per femur or spleen decreased to nonirradiated virgin mice values. M-CFC per maternal femur decreased to nonirradiated virgin mice values. M-CFC per maternal femur decreased following 1.5 Gy, but M-CFC per spleen appeared to be unaffected with doses from 0.5 to 2.0 Gy. (author)

  7. Low dose TBT exposure decreases amphipod immunocompetence and reproductive fitness.

    Science.gov (United States)

    Jacobson, Therese; Sundelin, Brita; Yang, Gongda; Ford, Alex T

    2011-01-17

    The antifouling agent tributyltin (TBT) is a highly toxic pollutant present in many aquatic ecosystems. Despite of regulations on the usage of TBT, it remains in high concentrations in sediments both in harbors and in off-shore sites. The toxicity of TBT in mollusks is well documented. However, adverse effects in other aquatic organisms, such as crustaceans, are less well known. This study is an effort to assess the effects of environmentally realistic concentrations of TBT on an ecologically important species in Swedish fresh and brackish water ecosystems, the benthic amphipod Monoporeia affinis. Field collected animals were exposed during gonad maturation to TBT (70 and 170 ng/g sediment d wt) for five weeks in static microcosms with natural sediment. Exposure concentrations were chosen to reflect effects at concentrations found in Swedish coastal sediment, but below expected effects on survival. TBT exposure resulted in a statistically significant adverse effect on oocyte viability and a doubling of the prevalence of microsporidian parasites in females, from 17% in the control to 34% in the 170 ng TBT/g sediment d wt exposure. No effects on survival were observed. Borderline significant effects were observed on male sexual maturation in the 70 ng TBT/g d wt exposure and on ecdysteroid levels in the 170 ng/g sediment d wt exposure. Both reproduction and parasite infection effects are of ecological importance since they have the potential to affect population viability in the field. This study gives further evidence to the connection between low dose contaminant exposure and increases in microsporidian parasite infection. Copyright © 2010 Elsevier B.V. All rights reserved.

  8. High versus low-dose rate brachytherapy for cervical cancer.

    Science.gov (United States)

    Patankar, Sonali S; Tergas, Ana I; Deutsch, Israel; Burke, William M; Hou, June Y; Ananth, Cande V; Huang, Yongmei; Neugut, Alfred I; Hershman, Dawn L; Wright, Jason D

    2015-03-01

    Brachytherapy plays an important role in the treatment of cervical cancer. While small trials have shown comparable survival outcomes between high (HDR) and low-dose rate (LDR) brachytherapy, little data is available in the US. We examined the utilization of HDR brachytherapy and analyzed the impact of type of brachytherapy on survival for cervical cancer. Women with stages IB2-IVA cervical cancer treated with primary (external beam and brachytherapy) radiotherapy between 2003-2011 and recorded in the National Cancer Database (NCDB) were analyzed. Generalized linear mixed models and Cox proportional hazards regression were used to examine predictors of HDR brachytherapy use and the association between HDR use and survival. A total of 10,564 women including 2681 (25.4%) who received LDR and 7883 (74.6%) that received HDR were identified. Use of HDR increased from 50.2% in 2003 to 83.9% in 2011 (Puse of HDR. While patients in the Northeast were more likely to receive HDR therapy, there were no other clinical or socioeconomic characteristics associated with receipt of HDR. In a multivariable Cox model, survival was similar between the HDR and LDR groups (HR=0.93; 95% CI 0.83-1.03). Similar findings were noted in analyses stratified by stage and histology. Kaplan-Meier analyses demonstrated no difference in survival based on type of brachytherapy for stage IIB (P=0.68), IIIB (P=0.17), or IVA (P=0.16) tumors. The use of HDR therapy has increased rapidly. Overall survival is similar for LDR and HDR brachytherapy. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Relationship to carcinogenesis of repetitive low-dose radiation exposure

    International Nuclear Information System (INIS)

    Ootsuyama, Akira

    2016-01-01

    We studied the carcinogenic effects caused by repetitive irradiation at a low dose, which has received attention in recent years, and examined the experimental methods used to evaluate radiation-induced carcinogenesis. For this experiment, we selected a mouse with as few autochthonous cancers as possible. Skin cancer was selected as the target for analysis, because it is a rare cancer in mice. Beta-rays were selected as the radiation source. The advantage of using beta-rays is weaker penetration power into tissues, thus protecting organs, such as the digestive and hematogenous organs. The benefit of our experimental method is that only skin cancer requires monitoring, and it is possible to perform long-term experiments. The back skin of mice was exposed repetitively to beta-rays three times a week until the occurrence of cancer or death, and the dose per exposure ranged from 0.5 to 11.8 Gy. With the high-dose range (2.5-11.8 Gy), the latency period and carcinogenic rate were almost the same in each experimental group. When the dose was reduced to 1-1.5 Gy, the latency period increased, but the carcinogenic rate remained. When the dose was further reduced to 0.5 Gy, skin cancer never happened, even though we continued irradiation until death of the last mouse in this group. The lifespan of 0.5 Gy group mice was the same as that of the controls. We showed that the 0.5 Gy dose did not cause cancer, even in mice exposed repetitively throughout their life span, and thus refer to 0.5 Gy as the threshold-like dose. (author)

  10. Pb low doses induced genotoxicity in Lactuca sativa plants.

    Science.gov (United States)

    Silva, S; Silva, P; Oliveira, H; Gaivão, I; Matos, M; Pinto-Carnide, O; Santos, C

    2017-03-01

    Soil and water contamination by lead (Pb) remains a topic of great concern, particularly regarding crop production. The admissible Pb values in irrigation water in several countries range from ≈0.1 to ≈5 mg L -1 . In order to evaluate putative effects of Pb within legal doses on crops growth, we exposed Lactuca sativa seeds and seedlings to increasing doses of Pb(NO 3 ) 2 up to 20 mg L -1 . The OECD parameter seed germination and seedling/plant growth were not affected by any of the Pb-concentrations used. However, for doses higher than 5 mg L -1 significant DNA damage was detected: Comet assay detected DNA fragmentation at ≥ 5 mg L -1 and presence of micronuclei (MN) were detected for 20 mg L -1 . Also, cell cycle impairment was observed for doses as low as 0.05 mg L -1 and 0.5 mg L -1 (mostly G 2 arrest). Our data show that for the low doses of Pb used, the OECD endpoints were not able to detect toxicity, while more sensitive endpoints (related with DNA damage and mitotic/interphase disorders) identified genotoxic and cytostatic effects. Furthermore, the nature of the genotoxic effect was dependent on the concentration. Finally, we recommend that MN test and the comet assay should be included as sensitive endpoints in (eco)toxicological assays. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  11. Evaluation of a low-dose neonatal chest radiographic system

    International Nuclear Information System (INIS)

    Burton, E.M.; Kirks, D.R.; Strife, J.L.; Henry, G.C.; Kereiakes, J.G.

    1988-01-01

    A new low-dose chest radiographic system for use in the neonatal nursery was evaluated. This test system, composed of a Du Pont Kevlar fiber-front cassette, Quanta fast-detail screen, Cronex 4L film (wide latitude), and additional yttrium filtration (0.1 mm), reduced the radiation dose in neonatal chest radiography by 69% (0.9 vs 2.9 mrad [0.009 vs 0.029 mGy]) as compared with a conventional system without added yttrium filtration; the thyroid dose was reduced by 76% (0.9 vs 3.7 mrad [0.009 vs 0.037 mGy]). The cumulative dose reduction was achieved through a combination of factors, including (1) beam hardening by the added yttrium filter, (2) increased X-ray transmission through the Kevlar cassette, and (3) a fast film-screen combination. Scatter radiation at distances of 1 and 6 ft. (0.3 and 1.8 m) was negligible for both systems. Image sharpness was compared for the conventional system with and without added yttrium filtration and for the Kevlar system with yttrium. Although sharpness of bony detail was unchanged by adding yttrium filtration to the conventional system, a decrease in sharpness was noted with the Kevlar system. Because image sharpness was affected in the test system, we are not using the Kevlar-Cronex 4L system for mobile chest radiography in the neonatal intensive care unit, despite dose reductions. However, further study is recommended to determine if there is a slower film-screen combination with yttrium filtration that will not degrade image sharpness

  12. A new study on the effects of low doses

    International Nuclear Information System (INIS)

    Dousset, M.; Jammet, H.

    1986-01-01

    A study conducted by prof. Rose has investigated mortality among 39540 employees of the UKAEA, from 1946 to 1978. The three main points are: 1. General mortality and mortality from malignant diseases are lower than in the population of England and Wales (74 and 79 per cent respectively), thus showing no major difference between workers monitored for exposure to radiation and other workers. 2. For monitored workers, the only death cause for which there is a statistically significant correlation with radiation exposure is prostate cancer; there are many cases especially in workers with doses exceeding 0.05 Sv (5 rem) and monitored for tritium. Such a correlation has never been found in any other epidemiologic survey of workers exposed to low-level doses, Hanford (USA) workers especially; conversely, mortality from either multiple myeloma or pancreas cancer is not found here. These facts plead for a cautious interpretation of the results as a whole. 3. A linear representation of the variations of leukemia and cancer mortality vs exposure results in lines, the slopes of which are 3 times higher than those of the lines adopted by ICRP; however, the 95% confidence intervals (-2.7 + 12.4 and -22 + 52.5) are such that the results are compatible with a null effect (slope 0) and even with a benefic effect (negative slope). They are therefore compatible with ICRP estimations. A recent attempt to evaluate the two main investigations on low-dose occupational exposures (UKAEA and Hanford) suggests a dose-response relationship very near that of ICRP [fr

  13. Lung cancer risk at low doses of alpha particles

    International Nuclear Information System (INIS)

    Hofmann, W.; Katz, R.; Zhang, C.X.

    1986-01-01

    A survey of inhabitant exposures arising from the inhalation of 222 Rn and 220 Rn progeny, and lung cancer mortality has been carried out in two adjacent areas in Guangdong Province, People's Republic of China, designated as the high background and the control area. Annual exposure rates are 0.38 working level months (WLM) per year in the high background, and 0.16 WLM/yr in the control area. In 14 yr of continuous study, from 1970 to 1983, age-adjusted mortality rates were found to be 2.7 per 10(5) living persons of all ages in the high background area, and 2.9 per 10(5) living persons in the control area. From this data, we conclude that we are unable to determine excess lung cancers over the normal fluctuations below a cumulative exposure of 15 WLM. This conclusion is supported by lung cancer mortality data from Austrian and Finnish high-background areas. A theoretical analysis of epidemiological data on human lung cancer incidence from inhaled 2 ]2'' 2 Rn and 220 Rn progeny, which takes into account cell killing as competitive with malignant transformation, leads to the evaluation of a risk factor which is either a linear-exponential or a quadratic-exponential function of the alpha-particle dose. Animal lung cancer data and theoretical considerations can be supplied to support either hypothesis. Thus we conclude that at our current stage of knowledge both the linear-exponential and the quadratic-exponential extrapolation to low doses seem to be equally acceptable for Rn-induced lung cancer risk, possibly suggesting a linear-quadratic transformation function with an exponential cell-killing term, or the influence of risk-modifying factors such as repair or proliferation stimuli

  14. Low dose CT perfusion in acute ischemic stroke

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, Amanda; Symons, Sean; Jakubovic, Raphael; Zhang, Liying; Aviv, Richard I. [Sunnybrook Health Sciences Centre, Toronto, ON (Canada); So, Aaron; Lee, Ting-Yim [Robarts Research Institute, London, Ontario (Canada)

    2014-12-15

    The purpose of this investigation is to determine if CT perfusion (CTP) measurements at low doses (LD = 20 or 50 mAs) are similar to those obtained at regular doses (RD = 100 mAs), with and without the addition of adaptive statistical iterative reconstruction (ASIR). A single-center, prospective study was performed in patients with acute ischemic stroke (n = 37; 54 % male; age = 74 ± 15 years). Two CTP scans were performed on each subject: one at 100 mAs (RD) and one at either 50 or 20 mAs (LD). CTP parameters were compared between the RD and LD scans in regions of ischemia, infarction, and normal tissue. Differences were determined using a within-subjects ANOVA (p < 0.05) followed by a paired t test post hoc analysis (p < 0.01). At 50 mAs, there was no significant difference between cerebral blood flow (CBF), cerebral blood volume (CBV), or time to maximum enhancement (Tmax) values for the RD and LD scans in the ischemic, infarcted, or normal contralateral regions (p < 0.05). At 20 mAs, there were significant differences between the RD and LD scans for all parameters in the ischemic and normal tissue regions (p > 0.05). CTP-derived CBF and CBV are not different at 50 mAs compared to 100 mAs, even without the addition of ASIR. Current CTP protocols can be modified to reduce the effective dose by 50 % without altering CTP measurements. (orig.)

  15. Treatment of burn injuries with keratinocyte cultures

    International Nuclear Information System (INIS)

    Syring, C.; Maenig, H.J.; Von Versen, R.; Bruck, J.

    1999-01-01

    The German Institute for Cell and Tissue Replacement (DIZG) provides burned patients with skin and amnion for a temporary wound closure. Severely burned patients (>60% BSA for adults, >40% BSA for children) were supplied with autologous and allogenic grafts from cultured keratinocytes. The keratinocyte culture is done under GMP-conditions using the method of Rheinwald and Green. The 3T3 fibroblasts were irradiated with 60 Gy and used as feeder cells to produce keratinocyte sheets within 3 weeks. In this time up to 6.000 cm are available. The sheets were harvested by detachment with dispase (1,2 U/ml), fixed to gauze and transported to the hospital. The DIZG has a 3 years experience in the treatment of burns with keratinocyte sheets. The sheets were transplanted to patients in different hospitals, the total transplanted area is about 30.000 cm. This paper describes the experiences with ten severely burned patients treated with keratinocyte sheet

  16. Pharmacological radionuclide ventriculography for detection of myocardial contractile reserve in patients after myocardial infarction: head-to-head comparison of low dose dobutamine and low dose dypiridamole

    International Nuclear Information System (INIS)

    Petrasinovic, Z.; Ostojic, M.; Beleslin, B.; Stojkovic, S.; Nedeljkovic, M.; Stankovic, G.; Dikic, A.; Pavlovic, S.; Sobic, D.

    2002-01-01

    Background. Low dose pharmacological stress echocardiography with either dobutamine or dipyridamole infusion has been proposed for recognition of myocardial viability. However, dependence on adequate acoustic window, observer experience, and the mild degree of wall motion changes make the viability assessment by stress echocardiography especially bothersome. The objective of the study was to evaluate the ability of low dose dobutamine and low dose dipyridamole radionuclide ventriculography to detect contractile reserve in patients after myocardial infarction and functional recovery after coronary angioplasty. Methods. The study group consisted of 20 consecutive patients (52±10 years, 17 male) with previous myocardial infarction and resting regional dyssynergy, in whom diagnostic cardiac catheterization revealed significant one-vessel coronary artery stenosis suitable for angioplasty. Each patient underwent equilibrium 99m-Tc radionuclide ventriculography which was performed at rest and during low dose dipyridamole (0.28 mg/kg over 2 minutes) and low dose dobutamine infusion (up to 10 mcg/kg/min). Left ventricular global and regional ejection fractions were determined. Increase of regional ejection fraction for >5% (inferoapical and posterolateral regions) or >10% (anteroseptal regions) during low dose dobutamine and dipyridamole in infarcted regions, as well as in the follow up period, was considered as index of contractile reserve. After 8 weeks of successful angioplasty, resting radionuclide ventriculography was repeated in all patients in order to identify functional recovery of the infarct zone. Results. Out of the 180 analyzed segments (20x9), 90 regional ejection fractions have shown depressed contractility. The mean of the regional ejection fractions showing depressed contractility increased from the resting value of 34±12% to 42±14% in the follow-up period (p=0.06). Of the 90 with baseline dyssynergy, 46 were responders during low-dose dobutamine (51

  17. Dosimetry Modeling for Focal Low-Dose-Rate Prostate Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Al-Qaisieh, Bashar [Leeds Cancer Centre, Leeds Teaching Hospitals NHS Trust, Leeds (United Kingdom); Mason, Josh, E-mail: joshua.mason@nhs.net [Leeds Cancer Centre, Leeds Teaching Hospitals NHS Trust, Leeds (United Kingdom); Bownes, Peter; Henry, Ann [Leeds Cancer Centre, Leeds Teaching Hospitals NHS Trust, Leeds (United Kingdom); Dickinson, Louise [Division of Surgery and Interventional Science, University College London, London (United Kingdom); Department of Radiology, Northwick Park Hospital, London North West NHS Trust, London (United Kingdom); Ahmed, Hashim U. [Division of Surgery and Interventional Science, University College London, London (United Kingdom); University College London Hospital, London (United Kingdom); Emberton, Mark [University College London Hospital, London (United Kingdom); Langley, Stephen [St Luke' s Cancer Centre, Guildford (United Kingdom)

    2015-07-15

    Purpose: Focal brachytherapy targeted to an individual lesion(s) within the prostate may reduce side effects experienced with whole-gland brachytherapy. The outcomes of a consensus meeting on focal prostate brachytherapy were used to investigate optimal dosimetry of focal low-dose-rate (LDR) prostate brachytherapy targeted using multiparametric magnetic resonance imaging (mp-MRI) and transperineal template prostate mapping (TPM) biopsy, including the effects of random and systematic seed displacements and interseed attenuation (ISA). Methods and Materials: Nine patients were selected according to clinical characteristics and concordance of TPM and mp-MRI. Retrospectively, 3 treatment plans were analyzed for each case: whole-gland (WG), hemi-gland (hemi), and ultra-focal (UF) plans, with 145-Gy prescription dose and identical dose constraints for each plan. Plan robustness to seed displacement and ISA were assessed using Monte Carlo simulations. Results: WG plans used a mean 28 needles and 81 seeds, hemi plans used 17 needles and 56 seeds, and UF plans used 12 needles and 25 seeds. Mean D90 (minimum dose received by 90% of the target) and V100 (percentage of the target that receives 100% dose) values were 181.3 Gy and 99.8% for the prostate in WG plans, 195.7 Gy and 97.8% for the hemi-prostate in hemi plans, and 218.3 Gy and 99.8% for the focal target in UF plans. Mean urethra D10 was 205.9 Gy, 191.4 Gy, and 92.4 Gy in WG, hemi, and UF plans, respectively. Mean rectum D2 cm{sup 3} was 107.5 Gy, 77.0 Gy, and 42.7 Gy in WG, hemi, and UF plans, respectively. Focal plans were more sensitive to seed displacement errors: random shifts with a standard deviation of 4 mm reduced mean target D90 by 14.0%, 20.5%, and 32.0% for WG, hemi, and UF plans, respectively. ISA has a similar impact on dose-volume histogram parameters for all plan types. Conclusions: Treatment planning for focal LDR brachytherapy is feasible. Dose constraints are easily met with a notable

  18. Experience with the low-dose in Bangladesh.

    Science.gov (United States)

    1982-03-01

    Condom sales (brand name Raja) have grown dramatically in Bangladesh and presently, sales account for over 50% of condoms distributed and represent more than 500,000 couple-years of protection (CYP). By contrast, sales of Maya, Noriday's brand name, accounts for only 8.5% of the total oral contraceptive (OC) distribution in Bangladesh and accounts for less than 50,000 CYP. According to the Director of the Bangladesh Social Marketing Program, poor performance of Maya is attributable to marketing factors. The mass media program was ineffectual in motivating new acceptors but it did make Maya a "household word" and it is now almost synonymous with the pill. Despite the nonuse, the number of potential OC users is high and therefore the CSM Project management decided that a new product with a distinct name, a new price, and a new marketing strategy was necessary. Norminest, a low-dose 0.35 mg ethinyl estradiol became available through AID and it was seen as a real alternative to those hormonal contraceptive products already available. The name selected was Ovacon and its packaging (which included goldleaf to signify high quality) was quite different than what came before. The price was set at 4.00 taka/cycle ($.21 in U.S.) which was higher than the Maya but lower than other commercially available OCs. Distribution of this new product was to center around physicians and other medical professionals in urban areas and promotion was to be limited to professional publications. This strategy had 2 objectives: establish personal contact with users and overcome the common practice of blaming the health of clients for the complaints heard. Ovacon was launched in June 1980 and now it is being detailed to rural practitioners. It is still not available in high traffic shops or through panwallahs. While sales have grown to 20-25,000 cycles/month, they are still about 1/2 of Maya sales. Together, these 2 methods represent 50,000 CYP. What was not anticipated was the magnitude of

  19. Spectroscopic characterization of low dose rate brachytherapy sources

    Science.gov (United States)

    Beach, Stephen M.

    The low dose rate (LDR) brachytherapy seeds employed in permanent radioactive-source implant treatments usually use one of two radionuclides, 125I or 103Pd. The theoretically expected source spectroscopic output from these sources can be obtained via Monte Carlo calculation based upon seed dimensions and materials as well as the bare-source photon emissions for that specific radionuclide. However the discrepancies resulting from inconsistent manufacturing of sources in comparison to each other within model groups and simplified Monte Carlo calculational geometries ultimately result in undesirably large uncertainties in the Monte Carlo calculated values. This dissertation describes experimentally attained spectroscopic outputs of the clinically used brachytherapy sources in air and in liquid water. Such knowledge can then be applied to characterize these sources by a more fundamental and metro logically-pure classification, that of energy-based dosimetry. The spectroscopic results contained within this dissertation can be utilized in the verification and benchmarking of Monte Carlo calculational models of these brachytherapy sources. This body of work was undertaken to establish a usable spectroscopy system and analysis methods for the meaningful study of LDR brachytherapy seeds. The development of a correction algorithm and the analysis of the resultant spectroscopic measurements are presented. The characterization of the spectrometer and the subsequent deconvolution of the measured spectrum to obtain the true spectrum free of any perturbations caused by the spectrometer itself is an important contribution of this work. The approach of spectroscopic deconvolution that was applied in this work is derived in detail and it is applied to the physical measurements. In addition, the spectroscopically based analogs to the LDR dosimetry parameters that are currently employed are detailed, as well as the development of the theory and measurement methods to arrive at these

  20. Lyssavirus infection: 'low dose, multiple exposure' in the mouse model.

    Science.gov (United States)

    Banyard, Ashley C; Healy, Derek M; Brookes, Sharon M; Voller, Katja; Hicks, Daniel J; Núñez, Alejandro; Fooks, Anthony R

    2014-03-06

    The European bat lyssaviruses (EBLV-1 and EBLV-2) are zoonotic pathogens present within bat populations across Europe. The maintenance and transmission of lyssaviruses within bat colonies is poorly understood. Cases of repeated isolation of lyssaviruses from bat roosts have raised questions regarding the maintenance and intraspecies transmissibility of these viruses within colonies. Furthermore, the significance of seropositive bats in colonies remains unclear. Due to the protected nature of European bat species, and hence restrictions to working with the natural host for lyssaviruses, this study analysed the outcome following repeat inoculation of low doses of lyssaviruses in a murine model. A standardized dose of virus, EBLV-1, EBLV-2 or a 'street strain' of rabies (RABV), was administered via a peripheral route to attempt to mimic what is hypothesized as natural infection. Each mouse (n=10/virus/group/dilution) received four inoculations, two doses in each footpad over a period of four months, alternating footpad with each inoculation. Mice were tail bled between inoculations to evaluate antibody responses to infection. Mice succumbed to infection after each inoculation with 26.6% of mice developing clinical disease following the initial exposure across all dilutions (RABV, 32.5% (n=13/40); EBLV-1, 35% (n=13/40); EBLV-2, 12.5% (n=5/40)). Interestingly, the lowest dose caused clinical disease in some mice upon first exposure ((RABV, 20% (n=2/10) after first inoculation; RABV, 12.5% (n=1/8) after second inoculation; EBLV-2, 10% (n=1/10) after primary inoculation). Furthermore, five mice developed clinical disease following the second exposure to live virus (RABV, n=1; EBLV-1, n=1; EBLV-2, n=3) although histopathological examination indicated that the primary inoculation was the most probably cause of death due to levels of inflammation and virus antigen distribution observed. All the remaining mice (RABV, n=26; EBLV-1, n=26; EBLV-2, n=29) survived the tertiary and

  1. Second International MELODI Workshop on Low Dose Risk Research - Slides of the presentations

    International Nuclear Information System (INIS)

    Repussard, J.; Weiss, W.; Quintana Trias, O.; Rosario Perez, M. del; Andersen, M.; Rudiger Trott, K.; Ottolenghi, A.; Smyth, V.; Graw, J.; Little, M.P.; Yonai, S.; Barcellos-Hoff, M.H.; Bouffler, S.; Chevillard, S.; Jeggo, P.; Sabatier, L.; Baatout, S.; Niwa, O.; Oesch, F.; Atkinson, M.; Averbeck, D.; Lloyd, D.; O'Neill, P.

    2011-01-01

    The MELODI (Multidisciplinary European Low Dose Initiative) mission is to impulse low dose risk research in Europe through a strategic research agenda (SRA) and road-map of priorities. The last presentation is dedicated to the SRA and its preference research programs. The other presentations deal principally with the low-dose exposure in medical uses of ionizing radiations, radiosensitivity, radiation-induced cataracts, or epidemiology and radiobiology of cardiovascular disease. This document is composed of the slides of the presentations

  2. The Potential Neurotoxic Effects of Low-Dose Sarin Exposure in a Guinea Pig Model

    Science.gov (United States)

    2002-01-01

    1 THE POTENTIAL NEUROTOXIC EFFECTS OF LOW-DOSE SARIN EXPOSURE IN A GUINEA PIG MODEL Melinda R. Roberson, PhD, Michelle B. Schmidt...Proving Ground, MD 21010 USA ABSTRACT This study is assessing the effects in guinea pigs of repeated low-dose exposure to the nerve...COVERED - 4. TITLE AND SUBTITLE The Potential Neurotoxic Effects Of Low-Dose Sarin Exposure In A Guinea Pig Model 5a. CONTRACT NUMBER 5b

  3. Systemic effects of low-dose dopamine during administration of cytarabine.

    Science.gov (United States)

    Connelly, James; Benani, Dina J; Newman, Matthew; Burton, Bradley; Crow, Jessica; Levis, Mark

    2017-09-01

    Purpose Low-dose dopamine has been utilized to improve renal blood flow, urine output, and reduce drug-induced nephrotoxicity. The purpose of this study was to assess changes in renal function, cardiovascular adverse events, and neurologic toxicity in patients receiving cytarabine with or without low-dose dopamine. Methods A retrospective, single-center, cohort study of patients receiving cytarabine at 667 mg/m 2 /dose or greater, with or without dopamine at ≤5 mcg/kg/min. Cohorts were based upon initiation or absence of low-dose dopamine; cytarabine only, cytarabine + pre- and day of low-dose dopamine, and cytarabine + post-low-dose dopamine. Renal outcomes (urine output, serum creatinine, and creatinine clearance) were compared with baseline and between cohorts. Safety endpoints (arrhythmias, tachycardia, and neurotoxicity) were compared between cohorts based on low-dose dopamine exposure. Results There was no difference in urine output from baseline in all cohorts. Comparing cytarabine only and pre- and day of low-dose dopamine cohorts, there was no difference in urine output. In those receiving low-dose dopamine, there was no difference in serum creatinine and creatinine clearance from baseline. No arrhythmias were documented during the study period, and there was no difference in the incidence of tachycardia between groups (P = 0.66). Neurotoxicity was reported in three patients who were on low-dose dopamine. Conclusion Though variation existed in individual patients administered low-dose dopamine, the use of low-dose dopamine did not significantly impact renal function in this small sample at a single institution. In addition, low-dose dopamine did not negatively impact cardiovascular function.

  4. 355-nm hypersensitization of optical fibers

    NARCIS (Netherlands)

    Canagasabey, A.; Canning, J.; Groothoff, N.

    2003-01-01

    A study is presented on 355-nm hypersensitization of optical fibers. It is found that the intrinsic 244-nm photosensitivity of boron-codoped germanosilicate optical fibers is enhanced by 355-nm hypersensitization. Hypersensitization through standard polymer coating is also demonstrated.

  5. Influence of low dose ionizing radiation on amplification and antitumor activity of LAK/TIL cells

    International Nuclear Information System (INIS)

    Liu Wei; Hou Dianjun; Qiao Jianwei; Shang Ximei; Li Jieqing

    2000-01-01

    Objective: To study the influence of low dose ionization on amplification and antitumor activity of LAK/TIL cells. Methods: TIL cells isolated from Lewis lung cancer tissues and LAK cells from spleen of tumor-bearing mouse were irradiated with different low doses of X-rays and were cultured after irradiation. Results: Low dose ionizing radiation improved the amplification volume of LAK/TIL cells, decreased the cell death ratio in amplification process, and increased the toxicity of LAK/TIL cells, Conclusions: Low dose ionizing radiation can result in amplification of biologically activated lymphocytes, and decreases the death ratio of the cells in amplification process

  6. Total Risk Management for Low Dose Radiation Exposures

    International Nuclear Information System (INIS)

    Simic, Z.; Mikulicic, V.; Sterc, D.

    2012-01-01

    Our civilization is witnessing about century of nuclear age mixed with enormous promises and cataclysmic threats. Nuclear energy seems to encapsulate both potential for pure good and evil or at least we humans are able to perceive that. These images are continuously with us and they are both helping and distracting from making best of nuclear potentials for civilization. Today with nuclear use significantly present and with huge potential to further improve our life with energy and medical use it is of enormous importance to try to have calmed, rational, and objective view on potential risks and certain benefits. Because all use of nuclear energy proved that their immediate risks are negligible (i.e., Three Mile Island and Fukushima) or much smaller than from the other alternatives (i.e., Chernobyl) it seems that the most important issue is the amount of risk from the long term effects to people from exposure to small doses of radiation. A similar issue is present in the increased use of modern computational tomography and other radiation sources use in medicine for examination and therapy. Finally, extreme natural exposures are third such potential risk sources. Definition of low doses varies depending on the way of delivery (i.e., single, multiple or continuous exposures), and for this paper usual dose of 100 mSv is selected as yearly upper amount. There are three very different scientifically supported views on the potential risks from the low doses exposure. The most conservative theory is that all radiation is harmful, and even small increments from background levels (i.e., 2-3 mSv) present additional risk. This view is called linear no threshold theory (LNT) and it is accepted as a regulatory conservative simple approach which guarantees safety. Risk is derived from the extrapolation of the measured effects of high levels of radiation. Opposite theory to LNT is hormesis which assumes that in fact small doses of radiation are helpful and they are improving our

  7. Low dose coronary CT angiography with 256-slice helical CT

    International Nuclear Information System (INIS)

    Zhang Xiaodong; Tang Binghang; Li Fangyun

    2011-01-01

    of 573) in B, 96.1% (548 of 570) in C, and 85.7% (505/589) in D, with no significant difference for A vs C (Z= -1.351, P>0.05) and with significant differences for B vs D (Z=-2.236, P<0.05). Linear correlation analysis indicated a significant degradation of image quality with the increase of heart rate using SAS mode (Spearman correlation, r=0.577, P<0.01). ROC analysis established an upper HR threshold of 78 bpm for obtaining diagnostic image quality using SAS mode (AUC = 0.827, P<0.05). The average radiation dose in group A [(2.6±0.5) mSv] reduced 75% comparing with that in group C [(10.6±2.3) mSv], and the average radiation dose in group B [(4.0±0.7) mSv] reduced 69% comparing with that in group D [(13.0±1.4) mSv]. Conclusion: Using SAS mode to perform low-dose CCTA with 256-slice helical CT could keep the image quality and reduce radiation dose significantly. Our preliminary experience suggests a good promise of this technique which could be applied to a wider group of patients such as with higher heart rates. (authors)

  8. The effects of repeated low-dose sarin exposure

    International Nuclear Information System (INIS)

    Shih, T.-M.; Hulet, S.W.; McDonough, J.H.

    2006-01-01

    This project assessed the effects of repeated low-dose exposure of guinea pigs to the organophosphorus nerve agent sarin. Animals were injected once a day, 5 days per week (Monday-Friday), for 2 weeks with fractions (0.3x, 0.4x, 0.5x, or 0.6x) of the established LD 5 dose of sarin (42 μg/kg, s.c.). The animals were assessed for changes in body weight, red blood cell (RBC) acetylcholinesterase (AChE) levels, neurobehavioral reactions to a functional observational battery (FOB), cortical electroencephalographic (EEG) power spectrum, and intrinsic acetylcholine (ACh) neurotransmitter (NT) regulation over the 2 weeks of sarin exposure and for up to 12 days postinjection. No guinea pig receiving 0.3, 0.4 or 0.5 x LD 5 of sarin showed signs of cortical EEG seizures despite decreases in RBC AChE levels to as low as 10% of baseline, while seizures were evident in animals receiving 0.6 x LD 5 of sarin as early as the second day; subsequent injections led to incapacitation and death. Animals receiving 0.5 x LD 5 sarin showed obvious signs of cholinergic toxicity; overall, 2 of 13 animals receiving 0.5 x LD 5 sarin died before all 10 injections were given, and there was a significant increase in the angle of gait in the animals that lived. By the 10th day of injection, the animals receiving saline were significantly easier to remove from their cages and handle and significantly less responsive to an approaching pencil and touch on the rump in comparison with the first day of testing. In contrast, the animals receiving 0.4 x LD 5 sarin failed to show any significant reductions in their responses to an approaching pencil and a touch on the rump as compared with the first day. The 0.5 x LD 5 sarin animals also failed to show any significant changes to the approach and touch responses and did not adjust to handling or removal from the cage from the first day of injections to the last day of handling. Thus, the guinea pigs receiving the 0.4 and 0.5 x LD 5 doses of sarin failed to

  9. Low-dose thiopurine with allopurinol co-therapy overcomes thiopurine intolerance and allows thiopurine continuation in inflammatory bowel disease.

    Science.gov (United States)

    Vasudevan, Abhinav; Beswick, Lauren; Friedman, Antony B; Moltzen, Alicia; Haridy, James; Raghunath, Ajay; Sparrow, Miles; van Langenberg, Daniel

    2018-02-10

    To assess the utility and tolerability of thiopurine-allopurinol co-therapy in inflammatory bowel disease (IBD) patients with intolerance to thiopurine monotherapy. A retrospective observational study assessed cases of thiopurine intolerance then switched to thiopurine allopurinol co-therapy between 2011 and 2015 at two centres. Indications for switch, dosing and subsequent clinical outcomes (including thiopurine persistence) were recorded. Of 767 patients on thiopurines for IBD, 89 (12%) were switched to co-therapy for intolerance. 64/89 (72%) had Crohn's disease, 38 (43%) were males, median age at switch was 40y (range 17-78), median IBD duration 6y (0-29). Median follow-up was 1.9y (0-5). Reasons for switching to co-therapy included fatigue (37%), hepatotoxicity (23%), nausea (23%), arthralgia (10%), headache (12%) and hypersensitivity reaction (4%). Overall, 66 (74%) patients remained on co-therapy until most recent review and achieved a clinical response. High rates of overcoming intolerance (62-100%) occurred with co-therapy for all reasons above, although fatigue was less amenable to switching than non-fatigue indications (62% vs 91%, p = <0.001). Of 34 patients not escalated to biologics with endoscopic data, 15 were in remission (44%) at most recent review. Low-dose thiopurine combined with allopurinol appears safe and effective in overcoming intolerances to thiopurine monotherapy in many cases. Copyright © 2018. Published by Elsevier Ltd.

  10. Low-dose ionizing radiation alleviates Aβ42-induced defective phenotypes in Drosophila Alzheimer's disease models

    International Nuclear Information System (INIS)

    Hwang, SooJin; Jeong, Hae Min; Nam, Seon Young

    2017-01-01

    Alzheimer's disease (AD) is the most common neurodegenerative disease that is characterized by amyloid plaques, progressive neuronal loss, and gradual deterioration of memory. Amyloid imaging using positron emission tomography (PET) radiotracers have been developed and approved for clinical use in the evaluation of suspected neurodegenerative disease, including AD. Particularly, previous studies involving low-dose ionizing radiation on Aβ 42-treated mouse hippocampal neurons have suggested a potential role for low-dose ionizing radiation in the treatment of AD. However, associated in vivo studies involving the therapy effects of low-dose ionizing radiation on AD are still insufficient. As a powerful cell biological system, Drosophila AD models have been generated and established a useful model organism for study on the etiology of human AD. In this study, we investigated the hormesis effects of low-dose ionizing radiation on Drosophila AD models. Our results suggest that low-dose ionizing radiation have the beneficial effects on not only the Aβ42-induced developmental defective phenotypes but also motor defects in Drosophila AD models. These results might be due to a regulation of apoptosis, and provide insight into the hormesis effects of low-dose ionizing radiation. Our results suggest that low-dose ionizing radiation have the beneficial effects on not only the Aβ42-induced developmental defective phenotypes but also motor defects in Drosophila AD models. These results might be due to a regulation of apoptosis, and provide insight into the hormesis effects of low-dose ionizing radiation.

  11. Low-dose add-back therapy during postoperative GnRH agonist treatment

    Directory of Open Access Journals (Sweden)

    Hsiao-Wen Tsai

    2016-02-01

    Conclusion: Low dose add-back therapy could effectively ameliorate hypoestrogenic side effects and simultaneously maintain the therapeutic response of GnRH agonist treatment. The treatment dropout was lower compared with a regular dose. Therefore, low dose add-back therapy can be considered a treatment choice during postoperative GnRH agonist treatment.

  12. The biological effects of low doses of radiation: medical, biological and ecological aspects

    International Nuclear Information System (INIS)

    Gun-Aajav, T.; Ajnai, L.; Manlaijav, G.

    2007-01-01

    Full text: The results of recent studies show that low doses of radiation make many different structural and functional changes in a cell and these changes are preserved for a long time. This phenomenon is called as effects of low doses of radiation in biophysics, radiation biology and radiation medicine. The structural and functional changes depend on doses and this dependence has non-linear and bimodal behaviour. More detail, the radiation effect goes up and reaches its maximum (Low doses maximum) in low doses region, then it goes down and takes its stationary means (there is a negative effect in a few cases). With increases in doses and with further increases it goes up. It is established that low dose's maximum depends on physiological state of a biological object, radiation quality and dose rate. During the experiments another special date was established. This specialty is that many different physical and chemical factors are mutually connected and have synergetic behaviour. At present, researches are concentrating their attention on the following three directions: 1. Direct and indirect interaction of radiation's low doses: 2. Interpretation of its molecular mechanism, regulation of the positive effects and elaboration of ways o removing negative effects: 3. Application of the objective research results into practice. In conclusion the authors mention the current concepts on interpretation of low doses effect mechanism, forward their own views and emphasize the importance of considering low doses effects in researches of environmental radiation pollution, radiation medicine and radiation protection. (author)

  13. Modeling low-dose-rate effects in irradiated bipolar-base oxides

    International Nuclear Information System (INIS)

    Graves, R.J.; Cirba, C.R.; Schrimpf, R.D.; Milanowski, R.J.; Saigne, F.; Michez, A.; Fleetwood, D.M.; Witczak, S.C.

    1997-02-01

    A physical model is developed to quantify the contribution of oxide-trapped charge to enhanced low-dose-rate gain degradation in BJTs. Simulations show that space charge limited transport is partially responsible for the low-dose-rate enhancement

  14. [Anticonvulsant hypersensitivity syndrome and lamotrigine-associated anticonvulsant hypersensitivity syndrome].

    Science.gov (United States)

    Taillia, H; Alla, P; Fournier, B; Bounolleau, P; Ouologem, M; Ricard, D; Sallansonnet-Froment, M; de Greslan, T; Renard, J-L

    2009-10-01

    Anticonvulsant hypersensitivity syndrome (AHS) is defined by the association of high fever, cutaneous rash and multiorgan-system abnormalities (incidence, one in 1000 to one in 10,000 exposures). Fatal complications are described in 10%. This reaction usually develops 1 to 12 weeks after initiation of an aromatic anticonvulsant. Drug rash with eosinophilia and systemic symptoms (DRESS) can be discussed as differential diagnosis. Several hypotheses have been put forward to explain the pathogenesis of AHS. These include accumulation of toxic metabolites, antibody production and viral infection. The one based on toxic metabolites has found the greatest acceptance due to the fact that it can be proven by an in vitro test, the lymphocyte toxicity assay. In vivo, skin biopsies show characteristic findings of erythema multiform or typical leucocytoclastic angitis. The patch-test is positive in 80% of the cases. Lamotrigine-associated anticonvulsant hypersensitivity syndrome (LASH) is rare and was described in 1998. We report two new cases demonstrating the two particular configurations of apparition of LASH found in the 14 cases from the review of literature (Pubmed: anticonvulsant hypersensitivity syndrome - lamotrigine): high doses of lamotrigine (or lamotrigine in very young or old patients), and lamotrigine associated with another anti-epileptic (phenobarbital or sodium valproate). We discuss the links between DRESS after lamotrigine and LASH as illustrated in a new case.

  15. Low-dose radiation induces drosophila innate immunity through toll pathway activation

    International Nuclear Information System (INIS)

    Seong, Ki Moon; Kim, Cha Soon; Lee, Byung-Sub; Nam, Seon Young; Yang, Kwang Hee; Kim, Ji-Young; Jin, Young-Woo; Park, Joong-Jean; Min, Kyung-Jin

    2012-01-01

    Numerous studies report that exposing certain organisms to low-dose radiation induces beneficial effects on lifespan, tumorigenesis, and immunity. By analyzing survival after bacterial infection and antimicrobial peptide gene expression in irradiated flies, we demonstrate that low-dose irradiation of Drosophila enhances innate immunity. Low-dose irradiation of flies significantly increased resistance against gram-positive and gram-negative bacterial infections, as well as expression of several antimicrobial peptide genes. Additionally, low-dose irradiation also resulted in a specific increase in expression of key proteins of the Toll signaling pathway and phosphorylated forms of p38 and N-terminal kinase (JNK). These results indicate that innate immunity is activated after low-dose irradiation through Toll signaling pathway in Drosophila. (author)

  16. Injury of the blood-testies barrier after low-dose-rate chronic radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Young Hoon; Bae Min Ji; Lee, Chang Geun; Yang, Kwang Mo; Jur, Kyu; Kim, Jong Sun [Dongnam Institute of Radiological and Medical Science, Busan (Korea, Republic of)

    2014-04-15

    The systemic effect of radiation increases in proportionally with the dose and dose rate. Little is known concerning the relationships between harmful effects and accumulated dose, which is derived from continuous low-dose rate radiation exposure. Recent our studies show that low-dose-rate chronic radiation exposure (3.49 mGy/h) causes adverse effects in the testis at a dose of 2 Gy (6 mGy/h). However, the mechanism of the low-dose-rate 2 Gy irradiation induced testicular injury remains unclear. The present results indicate that low-dose rate chronic radiation might affect the BTB permeability, possibly by decreasing levels of ZO-1, Occludin-1, and NPC-2. Furthermore, our results suggest that there is a risk of male infertility through BTB impairment even with low-dose-rate radiation if exposure is continuous.

  17. Electromagnetic hypersensitivity: Fact or fiction?

    International Nuclear Information System (INIS)

    Genuis, Stephen J.; Lipp, Christopher T.

    2012-01-01

    As the prevalence of wireless telecommunication escalates throughout the world, health professionals are faced with the challenge of patients who report symptoms they claim are connected with exposure to some frequencies of electromagnetic radiation (EMR). Some scientists and clinicians acknowledge the phenomenon of hypersensitivity to EMR resulting from common exposures such as wireless systems and electrical devices in the home or workplace; others suggest that electromagnetic hypersensitivity (EHS) is psychosomatic or fictitious. Various organizations including the World Health Organization as well as some nation states are carefully exploring this clinical phenomenon in order to better explain the rising prevalence of non-specific, multi-system, often debilitating symptoms associated with non-ionizing EMR exposure. As well as an assortment of physiological complaints, patients diagnosed with EHS also report profound social and personal challenges, impairing their ability to function normally in society. This paper offers a review of the sparse literature on this perplexing condition and a discussion of the controversy surrounding the legitimacy of the EHS diagnosis. Recommendations are provided to assist health professionals in caring for individuals complaining of EHS. - Highlights: ► Many people report symptoms when near devices emanating electromagnetic fields(EMF). ► Electromagnetic hypersensitivity (EHS) research has generated conflicting outcomes. ► Recent evidence suggests pathophysiological change in some individuals with EHS. ► EHS patients consistently report profound social and personal challenges. ► Clinicians need to be apprised of the EHS condition and potential interventions.

  18. Climate hypersensitivity to solar forcing?

    Directory of Open Access Journals (Sweden)

    W. Soon

    2000-05-01

    Full Text Available We compare the equilibrium climate responses of a quasi-dynamical energy balance model to radiative forcing by equivalent changes in CO2, solar total irradiance (Stot and solar UV (SUV. The response is largest in the SUV case, in which the imposed UV radiative forcing is preferentially absorbed in the layer above 250 mb, in contrast to the weak response from global-columnar radiative loading by increases in CO2 or Stot. The hypersensitive response of the climate system to solar UV forcing is caused by strongly coupled feedback involving vertical static stability, tropical thick cirrus ice clouds and stratospheric ozone. This mechanism offers a plausible explanation of the apparent hypersensitivity of climate to solar forcing, as suggested by analyses of recent climatic records. The model hypersensitivity strongly depends on climate parameters, especially cloud radiative properties, but is effective for arguably realistic values of these parameters. The proposed solar forcing mechanism should be further confirmed using other models (e.g., general circulation models that may better capture radiative and dynamical couplings of the troposphere and stratosphere.Key words: Meteorology and atmospheric dynamics (climatology · general or miscellaneous · Solar physics · astrophysics · and astronomy (ultraviolet emissions

  19. Upregulation of cathepsin S in psoriatic keratinocytes.

    Science.gov (United States)

    Schönefuss, Alexander; Wendt, Wiebke; Schattling, Benjamin; Schulten, Roxane; Hoffmann, Klaus; Stuecker, Markus; Tigges, Christian; Lübbert, Hermann; Stichel, Christine

    2010-08-01

    Cathepsin S (CATS) is a cysteine protease, well known for its role in MHC class II-mediated antigen presentation and extracellular matrix degradation. Disturbance of the expression or metabolism of this protease is a concomitant feature of several diseases. Given this importance we studied the localization and regulation of CATS expression in normal and pathological human/mouse skin. In normal human skin CATS-immunostaining is mainly present in the dermis and is localized in macrophages, Langerhans, T- and endothelial cells, but absent in keratinocytes. In all analyzed pathological skin biopsies, i.e. atopic dermatitis, actinic keratosis and psoriasis, CATS staining is strongly increased in the dermis. But only in psoriasis, CATS-immunostaining is also detectable in keratinocytes. We show that cocultivation with T-cells as well as treatment with cytokines can trigger expression and secretion of CATS, which is involved in MHC II processing in keratinocytes. Our data provide first evidence that CATS expression (i) is selectively induced in psoriatic keratinocytes, (ii) is triggered by T-cells and (iii) might be involved in keratinocytic MHC class II expression, the processing of the MHC class II-associated invariant chain and remodeling of the extracellular matrix. This paper expands our knowledge on the important role of keratinocytes in dermatological disease.

  20. Monte Carlo investigation of the low-dose envelope from scanned proton pencil beams

    International Nuclear Information System (INIS)

    Sawakuchi, Gabriel O; Titt, Uwe; Mirkovic, Dragan; Ciangaru, George; Zhu, X Ronald; Sahoo, Narayan; Gillin, Michael T; Mohan, Radhe

    2010-01-01

    Scanned proton pencil beams carry a low-dose envelope that extends several centimeters from the individual beam's central axis. Thus, the total delivered dose depends on the size of the target volume and the corresponding number and intensity of beams necessary to cover the target volume uniformly. This dependence must be considered in dose calculation algorithms used by treatment planning systems. In this work, we investigated the sources of particles contributing to the low-dose envelope using the Monte Carlo technique. We used a validated model of our institution's scanning beam line to determine the contributions to the low-dose envelope from secondary particles created in a water phantom and particles scattered in beam line components. Our results suggested that, for high-energy beams, secondary particles produced by nuclear interactions in the water phantom are the major contributors to the low-dose envelope. For low-energy beams, the low-dose envelope is dominated by particles undergoing multiple Coulomb scattering in the beam line components and water phantom. Clearly, in the latter situation, the low-dose envelope depends directly on beam line design features. Finally, we investigated the dosimetric consequences of the low-dose envelope. Our results showed that if not modeled properly the low-dose envelope may cause clinically relevant dose disturbance in the target volume. This work suggested that this low-dose envelope is beam line specific for low-energy beams, should be thoroughly experimentally characterized and validated during commissioning of the treatment planning system, and therefore is of great concern for accurate delivery of proton scanning beam doses.

  1. Enhanced low dose rate radiation effect test on typical bipolar devices

    International Nuclear Information System (INIS)

    Liu Minbo; Chen Wei; Yao Zhibin; He Baoping; Huang Shaoyan; Sheng Jiangkun; Xiao Zhigang; Wang Zujun

    2014-01-01

    Two types of bipolar transistors and nine types bipolar integrated circuit were selected in the irradiation experiment at different "6"0Co γ dose rate. The base current of bipolar transistor and input bias current of amplifier and comparator was measured, low dose enhance factor of test device was obtained. The results show that bipolar device have enhanced low dose rate sensitivity, enhancement factor of bipolar integrated circuit was bigger than that of transistor, and enhanced low dose rate sensitivity greatly varied with different structure and process of bipolar device. (authors)

  2. Low-dose radiation attenuates chemical mutagenesis in vivo. Cross adaptation

    International Nuclear Information System (INIS)

    Kakinuma, Shizuko; Yamauchi, Kazumi; Amasaki, Yoshiko; Nishimura, Mayumi; Shimada, Yoshiya

    2009-01-01

    The biological effects of low-dose radiation are not only of social concern but also of scientific interest. The radioadaptive response, which is defined as an increased radioresistance by prior exposure to low-dose radiation, has been extensively studied both in vitro and in vivo. Here we briefly review the radioadaptive response with respect to mutagenesis, survival rate, and carcinogenesis in vivo, and introduce our recent findings of cross adaptation in mouse thymic cells, that is, the suppressive effect of repeated low-dose radiation on mutation induction by the alkylating agent N-ethyl-N-nitrosourea. (author)

  3. Better management of wheat allergy using a very low-dose food challenge: A retrospective study.

    Science.gov (United States)

    Okada, Yu; Yanagida, Noriyuki; Sato, Sakura; Ebisawa, Motohiro

    2016-01-01

    Low-dose reactive wheat-allergic children are at a high risk of a positive oral food challenge (OFC). The present study aimed to evaluate whether the results of a very low-dose (VL) OFC would contribute to better wheat allergy management in this population. We retrospectively reviewed wheat-allergic subjects who underwent a VL OFC with 2 g of udon noodles (equivalent to 53 mg of wheat protein) and had a previous allergic reaction to management of some low-dose reactive wheat-allergic children from complete avoidance to partial wheat intake. Copyright © 2015 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

  4. Evaluation of Enhanced Low Dose Rate Sensitivity in Discrete Bipolar Junction Transistors

    Science.gov (United States)

    Chen, Dakai; Ladbury Raymond; LaBel, Kenneth; Topper, Alyson; Ladbury, Raymond; Triggs, Brian; Kazmakites, Tony

    2012-01-01

    We evaluate the low dose rate sensitivity in several families of discrete bipolar transistors across device parameter, quality assurance level, and irradiation bias configuration. The 2N2222 showed the most significant low dose rate sensitivity, with low dose rate enhancement factor of 3.91 after 100 krad(Si). The 2N2907 also showed critical degradation levels. The devices irradiated at 10 mrad(Si)/s exceeded specifications after 40 and 50 krad(Si) for the 2N2222 and 2N2907 devices, respectively.

  5. Mutation induction in cultured human cells after low-dose and low-dose-rate γ-ray irradiation. Detection by LOH analysis

    International Nuclear Information System (INIS)

    Umebayashi, Yukihiro; Iwaki, Masaya; Yatagai, Fumio; Honma, Masamitsu; Suzuki, Masao; Suzuki, Hiromi; Shimazu, Toru; Ishioka, Noriaki

    2007-01-01

    To study the genetic effects of low-doses and low-dose-rate ionizing radiation (IR), human lymphoblastoid TK6 cells were exposed to 30 mGy of γ-rays at a dose-rate of 1.2 mGy/hr. The frequency of early mutations (EMs) in the thymidine kinase (TK) gene locus was determined to be 1.7 x 10 -6 , or 1.9-fold higher than the level seen in unirradiated controls. These mutations were analyzed with a loss of heterozygosity (LOH) detection system, a methodology which has been shown to be sensitive to the effects of radiation. Among the 15 EMs observed after IR exposure, 8 were small interstitial-deletion events restricted to the TK gene locus. However, this specific type of event was not found in unirradiated controls. Although these results were observed under the limited conditions, they strongly suggest that the LOH detection system can be used for estimating the genetic effects of a low-dose IR exposure delivered at a low-dose-rate. (author)

  6. Proceedings of the 8. LOWRAD: International conference on the effects of low doses and very low doses of ionizing radiation on human health and biotopes

    International Nuclear Information System (INIS)

    2009-01-01

    Theoretical and experimental papers are presented in these proceedings covering the following subjects: radiation protection, dosimetry, radiation dosimetry, cells, technetium, plutonium, uranium, thorium, low dose irradiation, radiation doses, cesium, radiation chemistry, nuclear medicine, safety and occupational exposure, neoplasm, cytology and radioisotopes

  7. A systematic review of Bisphenol A "low dose" studies in the context of human exposure: a case for establishing standards for reporting "low-dose" effects of chemicals.

    Science.gov (United States)

    Teeguarden, Justin G; Hanson-Drury, Sesha

    2013-12-01

    Human exposure to the chemical Bisphenol A is almost ubiquitous in surveyed industrialized societies. Structural features similar to estrogen confer the ability of Bisphenol A (BPA) to bind estrogen receptors, giving BPA membership in the group of environmental pollutants called endocrine disruptors. References by scientists, the media, political entities, and non-governmental organizations to many toxicity studies as "low dose" has led to the belief that exposure levels in these studies are similar to humans, implying that BPA is toxic to humans at current exposures. Through systematic, objective comparison of our current, and a previous compilation of the "low-dose" literature to multiple estimates of human external and internal exposure levels, we found that the "low-dose" moniker describes exposures covering 8-12 orders of magnitude, the majority (91-99% of exposures) being greater than the upper bound of human exposure in the general infant, child and adult U.S. Population. "low dose" is therefore a descriptor without specific meaning regarding human exposure. Where human exposure data are available, for BPA and other environmental chemicals, reference to toxicity study exposures by direct comparison to human exposure would be more informative, more objective, and less susceptible to misunderstanding. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Synergistic Effects of Ad-Libitum Low-Dose Fructose Drinking and Low-Dose Streptozotocin Treatment in Wistar Rats: A Mild Model of Type 2 Diabetes

    Directory of Open Access Journals (Sweden)

    Asie Sadeghi

    2017-07-01

    Full Text Available To develop a convenient animal model of T2D by pretreatment with low-dose 10% w/v fructose (FRC solution followed by the injection of low doses of streptozotocin (STZ in Wistar rats. For this 8-week experimental study; rats were first fed a standard chow ad-libitum diet and either tap water (n=40 or 10% w/v FRC solution (n=40 for 4 weeks. Next, rats in each category were randomly allocated to 4 subgroups (n=10 each of low-dose STZ (25,35, and 45 mg/kg. The final mean fasting blood sugar (FBG of FRC+STZ45 (197±55.87 mg/dl were significantly higher than that of the STZ45 (P=0.015 and FRC (P=0.019 groups. FRC+STZ45 showed the highest insulin resistance demonstrated by insulin tolerance test [area under the curve (AUC of insulin tolerance test; P<0.05]. AUC was not significantly different between the STZ45 and non-STZ groups and between FRC and non-FRC fed groups. Furthermore, FBG levels did not differ between FRC and non-FRC groups. Body weight measurement showed that the FRC+STZ45 group had the lowest body weight compared to all other groups. Our data provide the evidence that FRC and STZ45 synergistically could induce hyperglycemia and insulin resistance in Wistar rats. Here we presented a feasible model for initial forms of T2D by employing pretreatment with low-dose FRC solution and treatment with low-dose STZ.

  9. Electromagnetic hypersensitivity: Fact or fiction?

    Energy Technology Data Exchange (ETDEWEB)

    Genuis, Stephen J., E-mail: sgenuis@ualberta.ca [University of Alberta (Canada); Lipp, Christopher T. [Faculty of Medicine at the University of Calgary (Canada)

    2012-01-01

    As the prevalence of wireless telecommunication escalates throughout the world, health professionals are faced with the challenge of patients who report symptoms they claim are connected with exposure to some frequencies of electromagnetic radiation (EMR). Some scientists and clinicians acknowledge the phenomenon of hypersensitivity to EMR resulting from common exposures such as wireless systems and electrical devices in the home or workplace; others suggest that electromagnetic hypersensitivity (EHS) is psychosomatic or fictitious. Various organizations including the World Health Organization as well as some nation states are carefully exploring this clinical phenomenon in order to better explain the rising prevalence of non-specific, multi-system, often debilitating symptoms associated with non-ionizing EMR exposure. As well as an assortment of physiological complaints, patients diagnosed with EHS also report profound social and personal challenges, impairing their ability to function normally in society. This paper offers a review of the sparse literature on this perplexing condition and a discussion of the controversy surrounding the legitimacy of the EHS diagnosis. Recommendations are provided to assist health professionals in caring for individuals complaining of EHS. - Highlights: Black-Right-Pointing-Pointer Many people report symptoms when near devices emanating electromagnetic fields(EMF). Black-Right-Pointing-Pointer Electromagnetic hypersensitivity (EHS) research has generated conflicting outcomes. Black-Right-Pointing-Pointer Recent evidence suggests pathophysiological change in some individuals with EHS. Black-Right-Pointing-Pointer EHS patients consistently report profound social and personal challenges. Black-Right-Pointing-Pointer Clinicians need to be apprised of the EHS condition and potential interventions.

  10. Design for low dose extrapolation of carcinogenicity data. Technical report No. 24

    International Nuclear Information System (INIS)

    Wong, S.C.

    1979-06-01

    Parameters for modelling dose-response relationships in carcinogenesis models were found to be very complicated, especially for distinguishing low dose effects. The author concluded that extrapolation always bears the danger of providing misleading information

  11. Study on cellular survival adaptive response induced by low dose irradiation of 153Sm

    International Nuclear Information System (INIS)

    Zhu Shoupeng; Xiao Dong

    1999-01-01

    The present study engages in determining whether low dose irradiation of 153 Sm could cut down the responsiveness of cellular survival to subsequent high dose exposure of 153 Sm so as to make an inquiry into approach the protective action of adaptive response by second irradiation of 153 Sm. Experimental results indicate that for inductive low dose of radionuclide 153 Sm 3.7 kBq/ml irradiated beforehand to cells has obvious resistant effect in succession after high dose irradiation of 153 Sm 3.7 x 10 2 kBq/ml was observed. Cells exposed to low dose irradiation of 153 Sm become adapted and therefore the subsequent cellular survival rate induced by high dose of 153 Sm is sufficiently higher than high dose of 153 Sm merely. It is evident that cellular survival adaptive response could be induced by pure low dose irradiation of 153 Sm only

  12. Treatment of symptomatic splenomegaly with low doses of radiotherapy: Retrospective analysis and review of the literature

    Directory of Open Access Journals (Sweden)

    Carolina de la Pinta

    2017-09-01

    Conclusion: Low doses of radiation therapy for treatment of symptomatic splenomegaly were effective, with a low rate of side effects. Splenic pain and abdominal discomfort completely improved and cytopenias rised to secure levels.

  13. Curcumin uptake enhancement using low dose light illumination during incubation in Candida albicans

    Science.gov (United States)

    Romano, Renan A.; Pratavieira, Sebastião.; da Silva, Ana P.; Kurachi, Cristina; Bagnato, Vanderlei S.; Guimarães, Francisco E. G.

    2017-07-01

    A new PDI protocol is presented in this study. C. albicans cells pre-illuminated with a low dose light demonstrated an increase of curcumin uptake when compared to dark incubation, leading to a higher PDI efficacy.

  14. Indications for suboptimal low-dose direct oral anticoagulants for non-valvular atrial fibrillation patients

    Directory of Open Access Journals (Sweden)

    Masahiko Umei, MD

    2017-10-01

    Conclusions: With good adherence, the clinical course associated with DOACs is comparatively good. In the future, suboptimal low-dose DOAC therapy may serve as an appropriate choice for some patients with a high risk of stroke and bleeding.

  15. Low-dose helical computed tomography (CT) in the perioperative workup of adolescent idiopathic scoliosis

    Energy Technology Data Exchange (ETDEWEB)

    Abul-Kasim, Kasim; Overgaard, Angelica; Maly, Pavel [Malmoe University Hospital, Department of Radiology, Section of Neuroradiology, University of Lund, Malmoe (Sweden); Ohlin, Acke [Malmoe University Hospital, Department of Orthopaedic Surgery, University of Lund, Malmoe (Sweden); Gunnarsson, Mikael [Malmoe University Hospital, Department of Radiation Physics, University of Lund, Malmoe (Sweden); Sundgren, Pia C. [University of Michigan Health Systems, Department of Radiology, Division of Neuroradiology, Ann Arbor (United States)

    2009-03-15

    The study aims were to estimate the radiation dose in patients examined with low dose spine CT and to compare it with that received by patients undergoing standard CT for trauma of the same region, as well as to evaluate the impact of dose reduction on image quality. Radiation doses in 113 consecutive low dose spine CTs were compared with those in 127 CTs for trauma. The inter- and intraobserver agreement in measurements of pedicular width, and vertebral rotation, measurements of signal-to-noise ratio and assessment of hardware status were the indicators in the evaluation of image quality. The effective dose of the low dose spine CT (0.37 mSv) was 20 times lower than that of a standard CT for trauma (13.09 mSv). This dose reduction conveyed no impact on image quality. This low dose spine CT protocol allows detailed evaluation that is necessary for preoperative planning and postoperative evaluation. (orig.)

  16. CANCER RISKS ATTRIBUTABLE TO LOW DOSES OF IONIZING RADIATION - ASSESSING WHAT WE REALLY KNOW?

    Science.gov (United States)

    Cancer Risks Attributable to Low Doses of Ionizing Radiation - What Do We Really Know?AbstractHigh doses of ionizing radiation clearly produce deleterious consequences in humans including, but not exclusively, cancer induction. At very low radiation doses the situatio...

  17. Low-Dose Radioactive Iodine Destroys Thyroid Tissue Left after Surgery

    Science.gov (United States)

    A low dose of radioactive iodine given after surgery for thyroid cancer destroyed (ablated) residual thyroid tissue as effectively as a higher dose, with fewer side effects and less exposure to radiation, according to two randomized controlled trials.

  18. Effects of low dose radiation on repair processes in human lymphocytes

    International Nuclear Information System (INIS)

    Tuschl, H.; Altmann, H.; Kovac, R.; Topaloglou, A.; Egg, D.; Guenther, R.

    1978-10-01

    DNA excision repair was investigated in lymphocytes of persons occupationally exposed to low dose radiation of 222 Rn. Autoradiographic studies of unscheduled DNA synthesis and measurement of 3 H-thymidine incorporation by repair replication into double stranded and single-strand containing DNA fractions obtained by BND cellulose chromatography seem to indicate a stimulatory effect of repeated low dose radiation on repair enzymes. (author)

  19. Low dose radiation exposure and atherosclerosis in ApoE{sup -/-} mice

    Energy Technology Data Exchange (ETDEWEB)

    Mitchel, R.E.J. [Atomic Energy of Canada Limited, Chalk River, ON (Canada); Hasu, M. [Univ. of Ottawa, Department of Pathology and Lab. Medicine, and Cellular and Molecular Medicine, Ottawa, ON (Canada); Univ. of Ottawa Heart Inst., Vascular Biology Group, Ottawa, ON (Canada); Bugden, M.; Wyatt, H. [Atomic Energy of Canada Limited, Chalk River, ON (Canada); Little, M. [Imperial Coll., Faculty of Medicine, St. Marys Campus, London (United Kingdom); Hildebrandt, G. [Univ. Hospital, Dept. of Radiotherapy, Rostock (Germany); Priest, N.D. [Atomic Energy of Canada Limited, Chalk River, ON (Canada); Whitman, S.C. [Univ. of Ottawa, Department of Pathology and Lab. Medicine, and Cellular and Molecular Medicine, Ottawa, ON (Canada); Univ. of Ottawa Heart Inst., Vascular Biology Group, Ottawa, ON (Canada)

    2010-07-01

    The hypothesis that single low dose exposures (0.025-0.5 Gy) to low LET radiation, given at either high (240 mGy/min) or low (1 mGy/min) dose rate, would promote aortic atherosclerosis was tested in female C57BI/6 mice genetically predisposed to this disease (ApoE-/-). Mice were exposed either at early stage disease (2 months of age) and examined 3 or 6 months later, or at late stage disease (8 months of age) and examined 2 or 4 months later. Compared to unexposed controls, all doses given at low or high dose rate at early stage disease had significant inhibitory effects on lesion growth and, at 25 or 50 mGy, on lesion frequency. No dose given at low dose rate had any effect on total serum cholesterol, but this was elevated by every dose given at high dose rate. Exposures at low dose rate had no effect on the percentage of lesion lipids contained within macrophages, and, at either high or low dose rate, had no significant effect on lesion severity. Exposure at late stage disease, to any dose at high dose rate, had no significant effect on lesion frequency, but at low dose rate some doses produced a small transient increase in this frequency. Exposure to low doses at low, but not high dose rate, significantly, but transiently reduced average lesion size, and at either dose rate transiently reduced lesion severity. Exposure to any dose at low dose rate (but not high dose rate) resulted in large and persistent decreases in serum cholesterol. These data indicate that a single low dose exposure, depending on dose and dose rate, generally protects against various measures of atherosclerosis in genetically susceptible mice. This result contrasts with the known, generally detrimental effects of high doses on this disease in the same mice, suggesting that a linear extrapolation of risk from high doses is not appropriate. (author)

  20. Radon Exposure and the Definition of Low Doses-The Problem of Spatial Dose Distribution.

    Science.gov (United States)

    Madas, Balázs G

    2016-07-01

    Investigating the health effects of low doses of ionizing radiation is considered to be one of the most important fields in radiological protection research. Although the definition of low dose given by a dose range seems to be clear, it leaves some open questions. For example, the time frame and the target volume in which absorbed dose is measured have to be defined. While dose rate is considered in the current system of radiological protection, the same cancer risk is associated with all exposures, resulting in a given amount of energy absorbed by a single target cell or distributed among all the target cells of a given organ. However, the biological effects and so the health consequences of these extreme exposure scenarios are unlikely to be the same. Due to the heterogeneous deposition of radon progeny within the lungs, heterogeneous radiation exposure becomes a practical issue in radiological protection. While the macroscopic dose is still within the low dose range, local tissue doses on the order of Grays can be reached in the most exposed parts of the bronchial airways. It can be concluded that progress in low dose research needs not only low dose but also high dose experiments where small parts of a biological sample receive doses on the order of Grays, while the average dose over the whole sample remains low. A narrow interpretation of low dose research might exclude investigations with high relevance to radiological protection. Therefore, studies important to radiological protection should be performed in the frame of low dose research even if the applied doses do not fit in the dose range used for the definition of low doses.

  1. Cancer Control Related to Stimulation of Immunity by Low-Dose Radiation

    OpenAIRE

    Liu, Shu-Zheng

    2006-01-01

    Previous studies showed that low dose radiation (LDR) could stimulate the immune system in both animal and human populations. This paper reviews the present status of relevant research as support to the use of LDR in clinical practice for cancer prevention and treatment. It has been demonstrated that radiation-induced changes in immune activity follows an inverse J-shaped curve, i.e., low dose stimulation and high dose suppression. The stimulation of immunity by LDR concerns most anticancer p...

  2. The genetic effects induced by an irradiation in low doses at Drosophila melanogaster

    International Nuclear Information System (INIS)

    Zajnullin, V.G.; Taskaev, A.I.; Moskalev, A.A.; Shaposhnikov, M.V.

    2006-01-01

    The review generalizes the results obtained in researches of genetic radiation effects for Drosophila melanogaster from contamination regions near the Chernobylsk NPP. The results of laboratory investigations of low dose irradiation effects on genotype variability and lifetime of Drosophila are presented too. It supposed that the main effect of low dose irradiation is caused by the induced genetic instability against the background of which the realization of different-directed radiobiological reactions is possible [ru

  3. Cytogenetic Low-Dose Hyperradiosensitivity Is Observed in Human Peripheral Blood Lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Seth, Isheeta [Department of Biological Sciences, Wayne State University, Detroit, Michigan (United States); Joiner, Michael C. [Department of Radiation Oncology, Wayne State University, Detroit, Michigan (United States); Tucker, James D., E-mail: jtucker@biology.biosci.wayne.edu [Department of Biological Sciences, Wayne State University, Detroit, Michigan (United States)

    2015-01-01

    Purpose: The shape of the ionizing radiation response curve at very low doses has been the subject of considerable debate. Linear-no-threshold (LNT) models are widely used to estimate risks associated with low-dose exposures. However, the low-dose hyperradiosensitivity (HRS) phenomenon, in which cells are especially sensitive at low doses but then show increased radioresistance at higher doses, provides evidence of nonlinearity in the low-dose region. HRS is more prominent in the G2 phase of the cell cycle than in the G0/G1 or S phases. Here we provide the first cytogenetic mechanistic evidence of low-dose HRS in human peripheral blood lymphocytes using structural chromosomal aberrations. Methods and Materials: Human peripheral blood lymphocytes from 2 normal healthy female donors were acutely exposed to cobalt 60 γ rays in either G0 or G2 using closely spaced doses ranging from 0 to 1.5 Gy. Structural chromosomal aberrations were enumerated, and the slopes of the regression lines at low doses (0-0.4 Gy) were compared with doses of 0.5 Gy and above. Results: HRS was clearly evident in both donors for cells irradiated in G2. No HRS was observed in cells irradiated in G0. The radiation effect per unit dose was 2.5- to 3.5-fold higher for doses ≤0.4 Gy than for doses >0.5 Gy. Conclusions: These data provide the first cytogenetic evidence for the existence of HRS in human cells irradiated in G2 and suggest that LNT models may not always be optimal for making radiation risk assessments at low doses.

  4. Low dose radiation exposure and atherosclerosis in ApoE-/- mice

    International Nuclear Information System (INIS)

    Mitchel, R.E.J.; Hasu, M.; Bugden, M.; Wyatt, H.; Little, M.; Hildebrandt, G.; Priest, N.D.; Whitman, S.C.

    2010-01-01

    The hypothesis that single low dose exposures (0.025-0.5 Gy) to low LET radiation, given at either high (240 mGy/min) or low (1 mGy/min) dose rate, would promote aortic atherosclerosis was tested in female C57BI/6 mice genetically predisposed to this disease (ApoE-/-). Mice were exposed either at early stage disease (2 months of age) and examined 3 or 6 months later, or at late stage disease (8 months of age) and examined 2 or 4 months later. Compared to unexposed controls, all doses given at low or high dose rate at early stage disease had significant inhibitory effects on lesion growth and, at 25 or 50 mGy, on lesion frequency. No dose given at low dose rate had any effect on total serum cholesterol, but this was elevated by every dose given at high dose rate. Exposures at low dose rate had no effect on the percentage of lesion lipids contained within macrophages, and, at either high or low dose rate, had no significant effect on lesion severity. Exposure at late stage disease, to any dose at high dose rate, had no significant effect on lesion frequency, but at low dose rate some doses produced a small transient increase in this frequency. Exposure to low doses at low, but not high dose rate, significantly, but transiently reduced average lesion size, and at either dose rate transiently reduced lesion severity. Exposure to any dose at low dose rate (but not high dose rate) resulted in large and persistent decreases in serum cholesterol. These data indicate that a single low dose exposure, depending on dose and dose rate, generally protects against various measures of atherosclerosis in genetically susceptible mice. This result contrasts with the known, generally detrimental effects of high doses on this disease in the same mice, suggesting that a linear extrapolation of risk from high doses is not appropriate. (author)

  5. The benefit of low dose prophylaxis in the treatment of hemophilia: a focus on China.

    Science.gov (United States)

    Wu, Runhui; Luke, Koon Hung

    2017-11-01

    Currently full dose prophylaxis is the standard of care in the treatment of hemophilia (World Federation of Hemophilia). However, the high costs prevent the use of standard or intermediate dose prophylaxis in China and other developing countries. Low dose prophylaxis would be a viable alternative treatment. At present global research data on the use of low dose prophylaxis is limited. Areas covered: Since 2007, China has been developing low dose prophylaxis as a high priority (90 % of moderate and severe hemophilia boys suffer joint disease by age 6 - 9). 11 studies were successfully conducted and published results showing evidence of the benefits of low dose prophylaxis to reduce joint bleeding. This new knowledge has been implemented into clinical practice in China. However the long-term outcome of arthropathy remains unclear and obstacles in execution exist. Expert commentary: In 2016, the first phenotype-based individualized prophylaxis study using four escalating low dose regimens on severe Chinese hemophilia A boys (China Individualized Prophylaxis Study (CHIP China)) launched. Using the previously published and imminent CHIP data, the goal for China is to establish an effective escalating low dose prophylaxis protocol for use in China as a standard of care.

  6. Super-low dose endotoxin pre-conditioning exacerbates sepsis mortality.

    Science.gov (United States)

    Chen, Keqiang; Geng, Shuo; Yuan, Ruoxi; Diao, Na; Upchurch, Zachary; Li, Liwu

    2015-04-01

    Sepsis mortality varies dramatically in individuals of variable immune conditions, with poorly defined mechanisms. This phenomenon complements the hypothesis that innate immunity may adopt rudimentary memory, as demonstrated in vitro with endotoxin priming and tolerance in cultured monocytes. However, previous in vivo studies only examined the protective effect of endotoxin tolerance in the context of sepsis. In sharp contrast, we report herein that pre-conditionings with super-low or low dose endotoxin lipopolysaccharide (LPS) cause strikingly opposite survival outcomes. Mice pre-conditioned with super-low dose LPS experienced severe tissue damage, inflammation, increased bacterial load in circulation, and elevated mortality when they were subjected to cecal-ligation and puncture (CLP). This is in opposite to the well-reported protective phenomenon with CLP mice pre-conditioned with low dose LPS. Mechanistically, we demonstrated that super-low and low dose LPS differentially modulate the formation of neutrophil extracellular trap (NET) in neutrophils. Instead of increased ERK activation and NET formation in neutrophils pre-conditioned with low dose LPS, we observed significantly reduced ERK activation and compromised NET generation in neutrophils pre-conditioned with super-low dose LPS. Collectively, our findings reveal a novel mechanism potentially responsible for the dynamic programming of innate immunity in vivo as it relates to sepsis risks.

  7. Super-low Dose Endotoxin Pre-conditioning Exacerbates Sepsis Mortality

    Directory of Open Access Journals (Sweden)

    Keqiang Chen

    2015-04-01

    Full Text Available Sepsis mortality varies dramatically in individuals of variable immune conditions, with poorly defined mechanisms. This phenomenon complements the hypothesis that innate immunity may adopt rudimentary memory, as demonstrated in vitro with endotoxin priming and tolerance in cultured monocytes. However, previous in vivo studies only examined the protective effect of endotoxin tolerance in the context of sepsis. In sharp contrast, we report herein that pre-conditioning with super-low or low dose endotoxin lipopolysaccharide (LPS cause strikingly opposite survival outcomes. Mice pre-conditioned with super-low dose LPS experienced severe tissue damage, inflammation, increased bacterial load in circulation, and elevated mortality when they were subjected to cecal-ligation and puncture (CLP. This is in contrast to the well-reported protective phenomenon with CLP mice pre-conditioned with low dose LPS. Mechanistically, we demonstrated that super-low and low dose LPS differentially modulate the formation of neutrophil extracellular trap (NET in neutrophils. Instead of increased ERK activation and NET formation in neutrophils pre-conditioned with low dose LPS, we observed significantly reduced ERK activation and compromised NET generation in neutrophils pre-conditioned with super-low dose LPS. Collectively, our findings reveal a mechanism potentially responsible for the dynamic programming of innate immunity in vivo as it relates to sepsis risks.

  8. The risk of low doses of ionising radiation and the linear no threshold relationship debate

    International Nuclear Information System (INIS)

    Tubiana, M.; Masse, R.; Vathaire, F. de; Averbeck, D.; Aurengo, A.

    2007-01-01

    The ICRP and the B.E.I.R. VII reports recommend a linear no threshold (L.N.T.) relationship for the estimation of cancer excess risk induced by ionising radiations (IR), but the 2005 report of Medicine and Science French Academies concludes that it leads to overestimate of risk for low and very low doses. The bases of L.N.T. are challenged by recent biological and animal experimental studies which show that the defence against IR involves the cell microenvironment and the immunologic system. The defence mechanisms against low doses are different and comparatively more effective than for high doses. Cell death is predominant against low doses. DNA repairing is activated against high doses, in order to preserve tissue functions. These mechanisms provide for multicellular organisms an effective and low cost defence system. The differences between low and high doses defence mechanisms are obvious for alpha emitters which show several greys threshold effects. These differences result in an impairment of epidemiological studies which, for statistical power purpose, amalgamate high and low doses exposure data, since it would imply that cancer IR induction and defence mechanisms are similar in both cases. Low IR dose risk estimates should rely on specific epidemiological studies restricted to low dose exposures and taking precisely into account potential confounding factors. The preliminary synthesis of cohort studies for which low dose data (< 100 mSv) were available show no significant risk excess, neither for solid cancer nor for leukemias. (authors)

  9. ATM phosphorylation in HepG2 cells following continuous low dose-rate irradiation

    International Nuclear Information System (INIS)

    Mei Quelin; Du Duanming; Chen Zaizhong; Liu Pengcheng; Yang Jianyong; Li Yanhao

    2008-01-01

    Objective: To investigate the change of ATM phosphorylation in HepG2 cells following a continuous low dose-rate irradiation. Methods: Cells were persistently exposed to low dose-rate (8.28 cGy/h) irradiation. Indirect immunofluorescence and Western blot were used to detect the expression of ATM phosphorylated proteins. Colony forming assay was used to observe the effect of a low dose-rate irradiation on HepG2 cell survival. Results: After 30 min of low dose-rate irradiation, the phosphorylation of ATM occurred. After 6 h persistent irradiation, the expression of ATM phosphorylated protein reached the peak value, then gradually decreased. After ATM phosphorylation was inhibited with Wortmannin, the surviving fraction of HepG2 cells was lower than that of the irradiation alone group at each time point (P<0.05). Conclusions: Continuous low dose-rate irradiation attenuated ATM phosphorylation, suggesting that continuous low dose-rate irradiation has a potential effect for increasing the radiosensitivity of HepG2 cells. (authors)

  10. Amalgam Contact Hypersensitivity Lesion: An Unusual Presentation ...

    African Journals Online (AJOL)

    Contact allergic reactions due to hypersensitivity to dental materials in professionals and ... Keywords: Amalgam, Amalgam contact hypersensitivity lesion, Lichenoid reaction, Oral mucosa ... was associated with mild burning sensation. The patient did ... OLLD in which oral and/or skin lesions appear in temporal association ...

  11. Burden of upper gastrointestinal symptoms in patients receiving low-dose acetylsalicylic acid for cardiovascular risk management

    DEFF Research Database (Denmark)

    Bytzer, Peter; Pratt, Stephen; Elkin, Eric

    2013-01-01

    Continuous low-dose acetylsalicylic acid (aspirin; ASA) is a mainstay of cardiovascular (CV) risk management. It is well established, however, that troublesome upper gastrointestinal (GI) symptoms are commonly experienced among low-dose ASA users.......Continuous low-dose acetylsalicylic acid (aspirin; ASA) is a mainstay of cardiovascular (CV) risk management. It is well established, however, that troublesome upper gastrointestinal (GI) symptoms are commonly experienced among low-dose ASA users....

  12. Risk of Low Dose/Low Dose Rate Ionizing Radiation to Humans Symposium Annual Meeting of the Environmental Mutagen Society: Agenda and Abstracts

    Energy Technology Data Exchange (ETDEWEB)

    Veigl, Martina L. [Environmental Mutagen Society (EMS), Reston, VA (United States); Case Western Reserve Univ., Cleveland, OH (United States). Case Comprehensive Cancer Center; Morgan, William F. [Univ. of Maryland, College Park, MD (United States); Schwartz, Jeffrey L. [Univ. of Washington, Seattle, WA (United States)

    2009-11-11

    The low dose symposium thoughtfully addressed controversy of risk from low dose radiation exposure, hormesis and radon therapy. The stem cell symposium cogently considered the role of DNA damage and repair in hematopoietic stem cells underlying aging and malignancy and provocatively presented evidence that stem cells may have distinct morphologies and replicative properties, as well as special roles in cancer initiation. In the epigenetics symposium, studies illustrated the long range interaction of epigenetic mechanisms, the roles of CTCF and BORIS in region/specific regulation of epigenetic processes, the impact of DNA damage on epigenetic processes as well as links between epigenetic mechanisms and early nutrition and bystander effects. This report shows the agenda and abstracts for this symposium.

  13. Low-dose total skin electron beam therapy for cutaneous lymphoma : Minimal risk of acute toxicities.

    Science.gov (United States)

    Kroeger, Kai; Elsayad, Khaled; Moustakis, Christos; Haverkamp, Uwe; Eich, Hans Theodor

    2017-12-01

    Low-dose total skin electron beam therapy (TSEBT) is attracting increased interest for the effective palliative treatment of primary cutaneous T‑cell lymphoma (pCTCL). In this study, we compared toxicity profiles following various radiation doses. We reviewed the records of 60 patients who underwent TSEBT for pCTCL between 2000 and 2016 at the University Hospital of Munster. The treatment characteristics of the radiotherapy (RT) regimens and adverse events (AEs) were then analyzed and compared. In total, 67 courses of TSEBT were administered to 60 patients. Of these patients, 34 (51%) received a standard dose with a median surface dose of 30 Gy and 33 patients (49%) received a low dose with the median surface dose of 12 Gy (7 salvage low-dose TSEBT courses were administered to 5 patients). After a median follow-up of 15 months, the overall AE rate was 100%, including 38 patients (57%) with grade 2 and 7 (10%) with grade 3 AEs. Patients treated with low-dose TSEBT had significantly fewer grade 2 AEs than those with conventional dose regimens (33 vs. 79%, P dose regimen compared to those with the conventional dose regimens (6 vs. 15%, P = 0.78). Multiple/salvage low-dose TSEBT courses were not associated with an increased risk of acute AEs. Low-dose TSEBT regimens are associated with significantly fewer grade 2 acute toxicities compared with conventional doses of TSEBT. Repeated/Salvage low-dose TSEBT, however, appears to be tolerable and can even be applied safely in patients with cutaneous relapses.

  14. Usefulness of low-dose CT in the detection of pulmonary metastasis of gestational trophoblastic tumours

    International Nuclear Information System (INIS)

    Xu, X.J.; Lou, F.L.; Zhang, M.M.; Pan, Z.M.; Zhang, L.

    2007-01-01

    Aim: To determine whether a low-dose spiral chest computed tomography (CT) examination could replace standard-dose chest CT in detecting pulmonary metastases in patients with gestational trophoblastic tumour (GTT). Materials and methods: In a prospective investigation, 67 chest CT examinations of 39 GTT patients were undertaken. All the patients underwent CT examinations using standard-dose (150 mAs, pitch 1, standard reconstruction algorithm) and low-dose (40 mAs, pitch 2, bone reconstruction algorithm) protocols. Two radiologists interpreted images independently. A metastasis was defined as a nodule within lung parenchyma that could not be attributed to a pulmonary vessel. The number of metastases detected with each protocol was recorded. The size of each lesion was measured and categorized as <5, 5-9.9, and ≥10 mm. Wilcoxon's signed rank test was used to assess the difference between the numbers of lesion detected by the two protocols. Results: The CT dose index (CTDI) for the standard-dose and low-dose CT protocols was 10.4 mGy and 1.4 mGy, respectively. One thousand, six hundred, and eighty-two metastases were detected by standard-dose CT, and 1460 lesions by the low-dose protocol. The numbers detected by low-dose CT were significantly less than those detected by standard-dose CT (Z = -3.776, p < 0.001), especially for nodules smaller than 5 mm (Z = -4.167, p < 0.001). However, the disease staging and risk score of the patients were not affected by use of the low-dose protocol. Conclusion: Low-dose chest CT can be used as a staging and follow-up procedure for patients with GTT

  15. Incidental renal tumours on low-dose CT lung cancer screening exams.

    Science.gov (United States)

    Pinsky, Paul F; Dunn, Barbara; Gierada, David; Nath, P Hrudaya; Munden, Reginald; Berland, Lincoln; Kramer, Barnett S

    2017-06-01

    Introduction Renal cancer incidence has increased markedly in the United States in recent decades, largely due to incidentally detected tumours from computed tomography imaging. Here, we analyze the potential for low-dose computed tomography lung cancer screening to detect renal cancer. Methods The National Lung Screening Trial randomized subjects to three annual screens with either low-dose computed tomography or chest X-ray. Eligibility criteria included 30 + pack-years, current smoking or quit within 15 years, and age 55-74. Subjects were followed for seven years. Low-dose computed tomography screening forms collected information on lung cancer and non-lung cancer abnormalities, including abnormalities below the diaphragm. A reader study was performed on a sample of National Lung Screening Trial low-dose computed tomography images assessing presence of abnormalities below the diaphragms and abnormalities suspicious for renal cancer. Results There were 26,722 and 26,732 subjects enrolled in the low-dose computed tomography and chest X-ray arms, respectively, and there were 104 and 85 renal cancer cases diagnosed, respectively (relative risk = 1.22, 95% CI: 0.9-1.5). From 75,126 low-dose computed tomography screens, there were 46 renal cancer diagnoses within one year. Abnormalities below the diaphragm rates were 39.1% in screens with renal cancer versus 4.1% in screens without (P cancer cases versus 13% of non-cases had abnormalities below the diaphragms; 55% of cases and 0.8% of non-cases had a finding suspicious for renal cancer (P cancers. The benefits to harms tradeoff of incidental detection of renal tumours on low-dose computed tomography is unknown.

  16. Cancer and low dose responses in vivo: implications for radiation protection

    International Nuclear Information System (INIS)

    Mitchel, R.E.J.

    2006-01-01

    Full text: Radiation protection practices assume that cancer risk is linearly proportional to total dose, without a threshold, both for people with normal cancer risk and for people who may be genetically cancer prone. Mice heterozygous for the Tp 53 gene are cancer prone, and their increased risk from high doses was not different from Tp 53 normal mice. However, in either Tp 53 normal or heterozygous mice, a single low dose of low LET radiation given at low dose rate protected against both spontaneous and radiation-induced cancer by increasing tumor latency. Increased tumor latency without a cancer frequency change implies that low doses in vivo primarily slow the process of genomic instability, consistent with the elevated capacity for correct DSB rejoining seen in low dose exposed cells. The in vivo animal data indicates that, for low doses and low dose rates in both normal and cancer prone adult mice, risk does not increase linearly with dose, and dose thresholds for increased risk exist. Below those dose thresholds (which are influenced by Tp 53 function) overall risk is reduced below that of unexposed control mice, indicating that Dose Rate Effectiveness Factors (DREF) may approach infinity, rather than the current assumption of 2. However, as dose decreases, different tissues appear to have different thresholds at which detriment turns to protection, indicating that individual tissue weighting factors (Wt) are also not constant, but vary from positive values to zero with decreasing dose. Measurements of Relative Biological Effect between high and low LET radiations are used to establish radiation weighting factors (Wr) used in radiation protection, and these are also assumed to be constant with dose. However, since the risk from an exposure to low LET radiation is not constant with dose, it would seem unlikely that radiation-weighting factors for high LET radiation are actually constant at low dose and dose rate

  17. Studies of health effects of low dose radiation and its application to medicare

    International Nuclear Information System (INIS)

    Yamaoka, Kiyonori; Ishida, Kenji; Iwasaki, Toshiyasu; Koana, Takao; Magae, Junji; Watanabe, Masami; Sakamoto, Kiyohiko

    2008-01-01

    The articles contain following 7 topics of low dose radiation effects. Studies of Health Effects of Low dose Radiation and Its Application to Medicare'', describes the indication of Rn therapy and investigations of its usefulness mechanism mainly in Misasa Spa, Okayama Pref. ''Challenges for the Paradigm Shift (CRIEPI Studies)'', introduces studies against the paradigm that radiation dose is linearly and proportionally hazardous. ''Studies of High Background Radiation Area (CRIEPI Studies)'', describes global HBRA studies on chromosome affection and effect of smoking in HBRA. ''Is the Radiation Effect on Man Proportional to Dose? (CRIEPI Studies)'', describes studies of immature sperm irradiated at low dose against Linear-Non-threshold Theory (LNT) hypothesis. ''Induction of Radiation Resistance by Low Dose Radiation and Assessment of Its Effect in Models of Human Diseases (CRIEPI Studies)'', explains the adoptive response in radiation effect, suppression of carcinogenesis and immune regulation by previous low dose radiation in the mouse, and improvement of diabetes in the db/db mouse. ''Modulation of Biological Effects of Low Dose Radiation: Adoptive Response, Bystander Effect, Genetic Instability and Radiation Hormesis'', summarizes findings of each item. ''Cancer Treatment with Low dose Radiation to the Whole Body'', describes basic studies in the mouse tumor in relation to suppression of carcinogenesis and metastasis, immune activation and treatment, and successful clinical studies in patients with ovary, colon cancers and malignant lymphoma where survival has been significantly improved: a base of recent European Organization for Research and Treatment of Cancer (EORTC) clinical trials. The mechanism is essentially based on immune activation of patients to cure the disease. (R.T.)

  18. Estimates of Health Detriments and Tissue Weighting Factors for Hong Kong Populations from Low Dose, Low Dose Rate and Low LET Ionising Radiation Exposure

    International Nuclear Information System (INIS)

    Lee, S.K.

    1998-01-01

    The total health detriments and the tissue weighting factors for the Hong Kong populations from low dose, low dose rate and low LET ionising radiation exposure are obtained according to the methodology recommended in ICRP Publication 60. The probabilities of fatal cancers for the general (ages 0-90) and working (ages 20-64) populations due to lifetime exposure at low dose and low dose rate are 4.9 x 10 -2 Sv -1 and 3.6 x 10 -2 Sv -1 respectively, comparing with the ICRP 60 estimates of 5.0 x 10 -2 Sv -1 and 4.0 x 10 -2 Sv -1 . The corresponding total health detriments for the general and working populations are 6.9 x 10 -2 Sv -1 and 4.9 x 10 -2 Sv -1 respectively comparing with the ICRP 60 estimates of 7.3 x 10 -2 Sv -1 and 5.6 x 10 -2 Sv -1 . Tissue weighting factors for the general population are 0.01 (bone surface and skin), 0.02 (liver, oesophagus and thyroid), 0.04 (bladder and breast), 0.08 (remainder), 0.10 (stomach), 0.11 (bone marrow), 0.15 (colon), 0.19 (lung) and 0.21 (gonads) and for the working population are 0.01 (bone surface and skin), 0.03 (liver, oesophagus and thyroid), 0.04 (breast), 0.06 (remainder), 0.07 (bladder), 0.08 (colon), 0.14 (bone marrow and stomach), 0.16 (lung) and 0.20 (gonads). (author)

  19. Relative implications of protective responses versus damage induction at low dose and low-dose-rate exposures, using the microdose approach

    Energy Technology Data Exchange (ETDEWEB)

    Feinendegen, L.E

    2003-07-01

    In reviewing tissue effects of low-dose radiation (1) absorbed dose to tissue is replaced by the sum of energy deposited with track events in cell-equivalent tissue micromasses, i.e. with microdose hits, in the number of exposed micromasses and (2) induced cell damage and adaptive protection are related to microdose hits in exposed micromasses for a given radiation quality. DNA damage increases with the number of microdose hits. They also can induce adaptive protection, mainly against endogenous DNA damage. This protection involves cellular defenses, DNA repair and damage removal. With increasing numbers of low linear energy transfer (LET) microdose hits in exposed micromasses, adaptive protection first tends to outweigh damage and then (above 200 mGy) fails and largely disappears. These experimental data predict that cancer risk coefficients derived by epidemiology at high-dose irradiation decline at low doses and dose rates when adaptive protection outdoes DNA damage. The dose-risk function should include both linear and non-linear terms at low doses. (author)

  20. Relative implications of protective responses versus damage induction at low dose and low-dose-rate exposures, using the microdose approach

    International Nuclear Information System (INIS)

    Feinendegen, L.E.

    2003-01-01

    In reviewing tissue effects of low-dose radiation (1) absorbed dose to tissue is replaced by the sum of energy deposited with track events in cell-equivalent tissue micromasses, i.e. with microdose hits, in the number of exposed micromasses and (2) induced cell damage and adaptive protection are related to microdose hits in exposed micromasses for a given radiation quality. DNA damage increases with the number of microdose hits. They also can induce adaptive protection, mainly against endogenous DNA damage. This protection involves cellular defenses, DNA repair and damage removal. With increasing numbers of low linear energy transfer (LET) microdose hits in exposed micromasses, adaptive protection first tends to outweigh damage and then (above 200 mGy) fails and largely disappears. These experimental data predict that cancer risk coefficients derived by epidemiology at high-dose irradiation decline at low doses and dose rates when adaptive protection outdoes DNA damage. The dose-risk function should include both linear and non-linear terms at low doses. (author)

  1. Comparison of radiosensitization by 41 deg. C hyperthermia during low dose rate irradiation and during pulsed simulated low dose rate irradiation in human glioma cells

    International Nuclear Information System (INIS)

    Raaphorst, G. Peter; Ng, Cheng E.; Shahine, Bilal

    1999-01-01

    Purpose: Long duration mild hyperthermia has been shown to be an effective radiosensitizer when given concurrently with low dose rate irradiation. Pulsed simulated low dose rate (PSLDR) is now being used clinically, and we have set out to determine whether concurrent mild hyperthermia can be an effective radiosensitizer for the PSLDR protocol. Materials and Methods: Human glioma cells (U-87MG) were grown to plateau phase and treated in plateau phase in order to minimize cell cycle redistribution during protracted treatments. Low dose rate (LDR) irradiation and 41 deg. C hyperthermia were delivered by having a radium irradiator inside a temperature-controlled incubator. PSLDR was given using a 150 kVp X-ray unit and maintaining the cells at 41 deg. C between irradiations. The duration of irradiation and concurrent heating depended on total dose and extended up to 48 h. Results: When 41 deg. C hyperthermia was given currently with LDR or PSLDR, the thermal enhancement ratios (TER) were about the same if the average dose rate for PSLDR was the same as for LDR. At higher average dose rates for PSLDR the TERs became less. Conclusions: Our data show that concurrent mild hyperthermia can be an effective sensitizer for PSLDR. This sensitization can be as effective as for LDR if the same average dose rate is used and the TER increases with decreasing dose rate. Thus mild hyperthermia combined with PSLDR may be an effective clinical protocol

  2. Hypersensitivity pneumonitis: an immunopathology review.

    Science.gov (United States)

    Woda, Bruce A

    2008-02-01

    Hypersensitivity pneumonitis (HSP) is an immunologically mediated alveolar and interstitial lung disease caused by repeated inhalation of organic dusts and some occupational agents. The pathogenesis of HSP is uncertain. A number of unexplained features of HSP remain, namely (1) why do so few exposed individuals develop clinical HSP, (2) what triggers an acute episode after prolonged periods of previous sensitization, and (3) what leads to disease progression. This article considers these issues and aims to discuss and clarify current concepts in pathogenesis. Pertinent literature review in conjunction with the author's personal interpretive opinion. Current data suggest that individuals with a T(H)1 dominant response are likely to develop clinical disease. There is also some evidence that genetic factors such as polymorphisms in the major histocompatibility complex, tumor necrosis factor alpha, and tissue inhibitor of metalloproteinase 3 are associated with the development of or resistance to the disease.

  3. Low-dose CT image reconstruction using gain intervention-based dictionary learning

    Science.gov (United States)

    Pathak, Yadunath; Arya, K. V.; Tiwari, Shailendra

    2018-05-01

    Computed tomography (CT) approach is extensively utilized in clinical diagnoses. However, X-ray residue in human body may introduce somatic damage such as cancer. Owing to radiation risk, research has focused on the radiation exposure distributed to patients through CT investigations. Therefore, low-dose CT has become a significant research area. Many researchers have proposed different low-dose CT reconstruction techniques. But, these techniques suffer from various issues such as over smoothing, artifacts, noise, etc. Therefore, in this paper, we have proposed a novel integrated low-dose CT reconstruction technique. The proposed technique utilizes global dictionary-based statistical iterative reconstruction (GDSIR) and adaptive dictionary-based statistical iterative reconstruction (ADSIR)-based reconstruction techniques. In case the dictionary (D) is predetermined, then GDSIR can be used and if D is adaptively defined then ADSIR is appropriate choice. The gain intervention-based filter is also used as a post-processing technique for removing the artifacts from low-dose CT reconstructed images. Experiments have been done by considering the proposed and other low-dose CT reconstruction techniques on well-known benchmark CT images. Extensive experiments have shown that the proposed technique outperforms the available approaches.

  4. Research on low radiation doses - A better understanding of low doses

    International Nuclear Information System (INIS)

    2016-01-01

    Radiation doses below 100 mSv are called low doses. Epidemiological research on the health hazards of low doses are difficult to do because numerous pathologies, particularly cancer, appear lifelong for genetical or environmental causes without any link with irradiation and it is very difficult to identify the real cause of a cancer. Another concern is that the impact on human health is weak and are observed only after a long period after irradiation. These features make epidemiological studies cumbersome to implement since they require vast cohorts and a very long-term follow-up. The extrapolation of the effects of higher doses to the domain of low doses does not meet reality and it is why the European Union takes part into the financing of such research. In order to gain efficiency, scientists work together through various European networks among them: HLEG (High Level Expert Group On European Low Dose Risk Research) or MELODI (Multidisciplinary European Low Dose Initiative). Several programs are underway or have been recently launched: -) the impact of Cesium contamination on children's health (Epice program), -) the study of the impact of medical imaging on children, -) the study of the health of children living near nuclear facilities, -) the relationship between radon and lung cancer, -) the effect of occupational low radiation doses, -) the effect of uranium dissolved in water on living organisms (Envirhom program). (A.C.)

  5. Bibliometrics analysis of the PubMed literatures on low-dose CT

    International Nuclear Information System (INIS)

    Wang Qian; Xia Guanghui; Ma Xiaohong; Zhao Xinming

    2012-01-01

    Objective: The purposes of this study were to evaluate the developmental rule and feature in low-dose CT examinations and to provide useful references for study in the future. Materials and Methods: The journal articles on PubMed from 2002 to 2011 were processed by Thomson Data Analyzer and five aspects were analysed: time, authors, institutions, journals, countries, and keywords. Results: The number of journal articles in low-dose CT examinations were 6 433, 3165 were from US (49.2%), 112 from China (1.4%); 3664 authors (80.42%) published only one article, the famous authors published more than 4 articles; there were 9 core journals in this area. In the last decade, the number and quality of the journal articles in low -dose CT have been dramatically increased. Conclusion: The interest on the low -dose CT examination has been steadily increasing, and world famous research teams have been established. The research in low-dose CT is a multi-discipline involving medicine, medical physics, and mathematics. Cooperation between multiple scientific domains is needed for the future studies. (authors)

  6. What can be learned from epidemiologic studies of persons exposed to low doses of radiation?

    International Nuclear Information System (INIS)

    Gilbert, E.S.

    1993-04-01

    The main objective of radiation risk assessment is to determine the risk of various adverse health effects associated with exposure to low doses and low dose rates. Extrapolation of risks from studies of persons exposed at high doses (generally exceeding 1 Sv) and dose rates has been the primary approach used to achieve this objective. The study of Japanese atomic bomb survivors in Hiroshima and Nagasaki has played an especially important role in risk assessment efforts. A direct assessment of the dose-response function based on studies of persons exposed at low doses and dose rates is obviously desirable. This paper focuses on the potential of both current and future nuclear workers studies for investigating the dose-response functions at low doses, and also discusses analyses making use of the low dose portion of the atomic bomb survivor data. Difficulties in using these data are the statistical imprecision of estimated dose-response parameters, and potential bias resulting from confounding factors and from uncertainties in dose estimates

  7. Dose rate effect on low-dose hyper-radiosensitivity with cells in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Geon-Min; Kim, Eun-Hee [Seoul National University, Seoul (Korea, Republic of)

    2016-10-15

    Low-dose hyper-radiosensitivity (HRS) is the phenomenon that mammalian cells exhibit higher sensitivity to radiation at low doses (< 0.5 Gy) than expected by the linear-quadratic model. At doses above 0.5Gy, the cellular response is recovered to the level expected by the linear-quadratic model. This transition is called the increased radio-resistance (IRR). HRS was first verified using Chinese hamster V79 cells in vitro by Marples and has been confirmed in studies with other cell lines including human normal and tumor cells. HRS is known to be induced by inactivation of ataxia telangiectasia-mutated (ATM), which plays a key role in repairing DNA damages. Considering the connection between ATM and HRS, one can infer that dose rate may affect cellular response regarding HRS at low doses. In this study, we quantitated the effect of dose rate on HRS by clonogenic assay with normal and tumor cells. The HRS of cells at low dose exposures is a phenomenon already known. In this study, we observed HRS of rat normal diencephalon cells and rat gliosarcoma cells at doses below 1 Gy. In addition, we found that dose rate mattered. HRS occurred at low doses, but only when total dose was delivered at a rate below certain level.

  8. Low dose gamma irradiation enhances defined signaling components of intercellular reactive oxygen-mediated apoptosis induction

    International Nuclear Information System (INIS)

    Bauer, G

    2011-01-01

    Transformed cells are selectively removed by intercellular ROS-mediated induction of apoptosis. Signaling is based on the HOCl and the NO/peroxynitrite pathway (major pathways) and the nitryl chloride and the metal-catalyzed Haber-Weiss pathway (minor pathways). During tumor progression, resistance against intercellular induction of apoptosis is acquired through expression of membrane-associated catalase. Low dose radiation of nontransformed cells has been shown to enhance intercellular induction of apoptosis. The present study was performed to define the signaling components which are modulated by low dose gamma irradiation. Low dose radiation induced the release of peroxidase from nontransformed, transformed and tumor cells. Extracellular superoxide anion generation was strongly enhanced in the case of transformed cells and tumor cells, but not in nontransformed cells. Enhancement of peroxidase release and superoxide anion generation either increased intercellular induction of apoptosis of transformed cells, or caused a partial protection under specific signaling conditions. In tumor cells, low dose radiation enhanced the production of major signaling components, but this had no effect on apoptosis induction, due to the strong resistance mechanism of tumor cells. Our data specify the nature of low dose radiation-induced effects on specific signaling components of intercellular induction of apoptosis at defined stages of multistep carcinogenesis.

  9. The short term effects of Low-dose-rate Radiation on EL4 Lymphoma Cell

    International Nuclear Information System (INIS)

    Bong, Jin Jong; Kang, Yu Mi; Shin, Suk Chull; Choi, Moo Hyun; Choi, Seung Jin; Kim, Hee Sun; Lee, Kyung Mi

    2012-01-01

    To determine the biological effects of low-dose-rate radiation ( 137 Cs, 2.95 mGy/h) on EL4 lymphoma cells during 24 h, we investigated the expression of genes related to apoptosis, cell cycle arrest, DNA repair, iron transport, and ribonucleotide reductase. EL4 cells were continuously exposed to low-dose-rate radiation (total dose: 70.8 mGy) for 24 h. We analyzed cell proliferation and apoptosis by trypan blue exclusion and flow cytometry, gene expression by real-time PCR, and protein levels with the apoptosis ELISA kit. Apoptosis increased in the Low-dose-rate irradiated cells, but cell number did not differ between non- (Non-IR) and Low-dose-rate irradiated (LDR-IR) cells. In concordance with apoptotic rate, the transcriptional activity of ATM, p53, p21, and Parp was upregulated in the LDR-IR cells. Similarly, Phospho-p53 (Ser15), cleaved caspase 3 (Asp175), and cleaved Parp (Asp214) expression was upregulated in the LDR-IR cells. No difference was observed in the mRNA expression of DNA repair-related genes (Msh2, Msh3, Wrn, Lig4, Neil3, ERCC8, and ERCC6) between Non-IR and LDR-IR cells. Interestingly, the mRNA of Trfc was upregulated in the LDR-IR cells. Therefore, we suggest that short-term Low-dose-rate radiation activates apoptosis in EL4 lymphoma cells.

  10. The short term effects of Low-dose-rate Radiation on EL4 Lymphoma Cell

    Energy Technology Data Exchange (ETDEWEB)

    Bong, Jin Jong; Kang, Yu Mi; Shin, Suk Chull; Choi, Moo Hyun; Choi, Seung Jin; Kim, Hee Sun [Radiation Health Research Institute, Korea Hydro and Nuclear Power Co., Ltd, Seoul (Korea, Republic of); Lee, Kyung Mi [Global Research Lab, BAERI Institute, Dept. of Biochemistry and Molecular Biology, Korea University College of Medicine, Seoul (Korea, Republic of)

    2012-06-15

    To determine the biological effects of low-dose-rate radiation ({sup 137}Cs, 2.95 mGy/h) on EL4 lymphoma cells during 24 h, we investigated the expression of genes related to apoptosis, cell cycle arrest, DNA repair, iron transport, and ribonucleotide reductase. EL4 cells were continuously exposed to low-dose-rate radiation (total dose: 70.8 mGy) for 24 h. We analyzed cell proliferation and apoptosis by trypan blue exclusion and flow cytometry, gene expression by real-time PCR, and protein levels with the apoptosis ELISA kit. Apoptosis increased in the Low-dose-rate irradiated cells, but cell number did not differ between non- (Non-IR) and Low-dose-rate irradiated (LDR-IR) cells. In concordance with apoptotic rate, the transcriptional activity of ATM, p53, p21, and Parp was upregulated in the LDR-IR cells. Similarly, Phospho-p53 (Ser15), cleaved caspase 3 (Asp175), and cleaved Parp (Asp214) expression was upregulated in the LDR-IR cells. No difference was observed in the mRNA expression of DNA repair-related genes (Msh2, Msh3, Wrn, Lig4, Neil3, ERCC8, and ERCC6) between Non-IR and LDR-IR cells. Interestingly, the mRNA of Trfc was upregulated in the LDR-IR cells. Therefore, we suggest that short-term Low-dose-rate radiation activates apoptosis in EL4 lymphoma cells.

  11. Hypersensitivity reactions in patients receiving hemodialysis.

    Science.gov (United States)

    Butani, Lavjay; Calogiuri, Gianfranco

    2017-06-01

    To describe hypersensitivity reactions in patients receiving maintenance hemodialysis. PubMed search of articles published during the past 30 years with an emphasis on publications in the past decade. Case reports and review articles describing hypersensitivity reactions in the context of hemodialysis. Pharmacologic agents are the most common identifiable cause of hypersensitivity reactions in patients receiving hemodialysis. These include iron, erythropoietin, and heparin, which can cause anaphylactic or pseudoallergic reactions, and topical antibiotics and anesthetics, which lead to delayed-type hypersensitivity reactions. Many hypersensitivity reactions are triggered by complement activation and increased bradykinin resulting from contact system activation, especially in the context of angiotensin-converting enzyme inhibitor use. Several alternative pharmacologic preparations and dialyzer membranes are available, such that once an etiology for the reaction is established, recurrences can be prevented without affecting the quality of care provided to patients. Although hypersensitivity reactions are uncommon in patients receiving hemodialysis, they can be life-threatening. Moreover, considering the large prevalence of the end-stage renal disease population, the implications of such reactions are enormous. Most reactions are pseudoallergic and not mediated by immunoglobulin E. The multiplicity of potential exposures and the complexity of the environment to which patients on dialysis are exposed make it challenging to identify the precise cause of these reactions. Great diligence is needed to investigate hypersensitivity reactions to avoid recurrence in this high-risk population. Copyright © 2017 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  12. Low-dose aspirin or other nonsteroidal anti-inflammatory drug use and prostate cancer risk

    DEFF Research Database (Denmark)

    Skriver, Charlotte; Dehlendorff, Christian; Borre, Michael

    2016-01-01

    PURPOSE: Increasing evidence suggests that aspirin use may protect against prostate cancer. In a nationwide case-control study, using Danish high-quality registry data, we evaluated the association between the use of low-dose aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs......) and the risk of prostate cancer. METHODS: We identified 35,600 patients (cases) with histologically verified prostate cancer during 2000-2012. Cases were matched to 177,992 population controls on age and residence by risk-set sampling. Aspirin and nonaspirin NSAID exposure was defined by type, estimated dose......, duration, and consistency of use. We used conditional logistic regression to estimate odds ratios (ORs), with 95 % confidence intervals (CIs), for prostate cancer associated with low-dose aspirin (75-150 mg) or nonaspirin NSAID use, adjusted for potential confounders. RESULTS: Use of low-dose aspirin...

  13. Whole body exposure to low-dose γ-radiation enhances the antioxidant defense system

    International Nuclear Information System (INIS)

    Pathak, C.M.; Avti, P.K.; Khanduja, K.L.; Sharma, S.C.

    2008-01-01

    It is believed that the extent of cellular damage by low- radiation dose is proportional to the effects observed at high radiation dose as per the Linear-No-Threshold (LNT) hypothesis. However, this notion may not be true at low-dose radiation exposure in the living system. Recent evidence suggest that the living organisms do not respond to ionizing radiations in a linear manner in the low dose range 0.01-0.5Gy and rather restore the homeostasis both in vivo and in vitro by normal physiological mechanisms such as cellular and DNA repair processes, immune reactions, antioxidant defense, adaptive responses, activation of immune functions, stimulation of growth etc. In this study, we have attempted to find the critical radiation dose range and the post irradiation period during which the antioxidant defense systems in the lungs, liver and kidneys remain stimulated in these organs after whole body exposure of the animals to low-dose radiation

  14. Radiation protection and environment day the low doses in everyday life

    International Nuclear Information System (INIS)

    2007-01-01

    The consequences of low doses exposures are difficult to explore and the studies give often place to controversies. According to the are, differences exist in the methodological approaches. It results from it a confusion on the acceptable levels of exposure, even on the definition of low dose. This day organised by the sections 'non ionizing and research and health of the French society of radiation protection (S.F.R.P.), will be a meeting between professionals of different disciplines, to compare the approaches used for the ionizing and non ionizing radiations as well as the chemical and microbiological agents. It will allow to share the knowledge and the abilities and to progress on methodologies adapted to the evaluation and the management of risks in relation with low doses. (N.C.)

  15. Effects of low dose radiation on antioxidant enzymes after radiotherapy of tumor-bearing mice

    International Nuclear Information System (INIS)

    Li Jin; Gao Gang; Wang Qin; Tang Weisheng; Liu Xiaoqiu; Wang Zhiquan

    2005-01-01

    Objective: To search for effects of low dose radiation on the activities of antioxidant enzymes after radiotherapy of tumor-bearing mice. Methods: Superoxide dismutase (SOD), glutathione-S-transferase (GST) and catalase (CAT) were all determined by chemical colorimetry. Results: Low dose radiation increase the activities of antioxidant enzymes superoxide dismutase (SOD), glutathione-S-transferase (GST) and catalase (CAT) in serum of tumor-bearing mice more markedly than those in the unirradiated controls. The activities of antioxidant enzymes SOD, GST, CAT in serum of tumor-bearing mice (d 5 , d 3 ) irradiated with 5cGy 6h before 2.0 Gy radiation are obviously higher than those of the group (c 3 , c 5 ) given with radiotherapy only. Conclusion: The increase in the activities of antioxidant enzymes in serum of tumor-bearing mice triggered by low dose radiation could partly contribute to the protective mechanism. (authors)

  16. Chromosome aberrations induced by low doses of X-rays in human lymphocytes in vitro

    International Nuclear Information System (INIS)

    Ziemba-Zoltowska, B.; Bocian, E.; Rosiek, O.; Sablinski, J.

    1980-01-01

    Curves derived from the dose-response data for the yield of aberrations in human lymphocytes can be represented by a quadratic equation at all but low dose ranges. A calibration curve has therefore been determined at a low dose range of X-radiation (11.5 to 57.5 rad). The frequencies of dicentrics plus centric rings, and of acentrics were better fitted by linear dose-response models than quadratic. The linearity of the relationship indicated that asymmetrical chromosome exchanges at low doses of radiation are produced predominantly by a single track mechanism. A dose-response curve for dicentrics plus centric rings (5 to 60 rad) has also been derived by pooling published data with the results of this study. This calibration curve is relevant to cytogenetic dosimetry in radiological protection. (UK)

  17. Low doses of ionizing radiation to mammalian cells may rather control than cause DNA damage

    International Nuclear Information System (INIS)

    Feinendegen, L.E.; Sondhaus, C.A.; Altman, K.I.

    1998-01-01

    This report examines the origin of tissue effects that may follow from different cellular responses to low-dose irradiation, using published data. Two principal categories of cellular responses are considered. One response category relates to the probability of radiation-induced DNA damage. The other category consists of low-dose induced metabolic changes that induce mechanisms of DNA damage mitigation, which do not operate at high levels of exposure. Modeled in this way, tissue is treated as a complex adaptive system. The interaction of the various cellular responses results in a net tissue dose-effect relation that is likely to deviate from linearity in the low-dose region. This suggests that the LNT hypothesis should be reexamined. This paper aims at demonstrating tissue effects as an expression of cellular responses, both damaging and defensive, in relation to the energy deposited in cell mass, by use of microdosimetric concepts

  18. On the common mechanism for initiation of different effects of low doses of ionizing radiations

    International Nuclear Information System (INIS)

    Ehjdus, L.Kh.

    1996-01-01

    Main regularities of different endpoints of ionizing radiation low dose effects (adaptive response, stimulation of proliferation, special radiosensitivity of lymphoid cells, and others) have been examined. It has been shown that these endpoints have a commonness for the dose interval, the shape of the dose-response curve, the reverse effect of dose rate, non-specificity toward initiating agents, and others. An explanation is suggested for the common mechanism of the initiation of all the studied low dose effects, basing on the theory of the non-specific reaction of cell to external influences. It is concluded that initiation of the low dose effects is conditioned by radiation induced damage of functions of plasmic and internal membranes

  19. [Efficacy of low-dose tadalafil on ED assessed by Self-Esteem and Relationship Questionnaire].

    Science.gov (United States)

    Li, Jing-Ping; Li, Fei; Guo, Wen-Bin; Zhou, Qi-Zhao; Liu, Cun-Dong; Mao, Xiang-Ming; Tan, Wan-Long; Zheng, Shao-Bin

    2010-12-01

    To explore the effects of low-dose oral tadalafil on self-esteem, confidence and sexual relationship in ED patients. We treated 17 ED patients with oral tadalafil at the low dose of 5 mg once daily for 12 weeks, and used the paired t test to compare their scores on The Self-Esteem and Relationship Questionnaire (SEAR) and IIEF-5 and the results of nocturnal penile tumescence (NPT) obtained by nocturnal electrobioimpedance volumetric assessment (NEVA) before and after the medication. The scores on SEAR and IIEF-5 were significantly increased (P P Low-dose oral tadalafil once daily can significantly improve the self-esteem, confidence, sexual relationship satisfaction and NPT of ED patients.

  20. Biological effects of low-dose ionizing radiation exposure; Biologische Wirkungen niedriger Dosen ionisierender Strahlung

    Energy Technology Data Exchange (ETDEWEB)

    Reinoehl-Kompa, Sabine; Baldauf, Daniela; Heller, Horst (comps.)

    2009-07-01

    The report on the meeting of the Strahlenschutzkommission 2007 concerning biological effects of low-dose ionizing radiation exposure includes the following contributions: Adaptive response. The importance of DNA damage mechanisms for the biological efficiency of low-energy photons. Radiation effects in mammography: the relative biological radiation effects of low-energy photons. Radiation-induced cataracts. Carcinomas following prenatal radiation exposure. Intercellular apoptosis induction and low-dose irradiation: possible consequences for the oncogenesis control. Mechanistic models for the carcinogenesis with radiation-induced cell inactivation: application to all solid tumors in the Japanese atomic bomb survivors. Microarrays at low radiation doses. Mouse models for the analysis of biological effects of low-dose ionizing radiation. The bystander effect: observations, mechanisms and implications. Lung carcinoma risk of Majak workers - modeling of carcinogenesis and the bystander effect. Microbeam studies in radiation biology - an overview. Carcinogenesis models with radiation-induced genomic instability. Application to two epidemiological cohorts.

  1. Improving abdomen tumor low-dose CT images using a fast dictionary learning based processing

    International Nuclear Information System (INIS)

    Chen Yang; Shi Luyao; Shu Huazhong; Luo Limin; Coatrieux, Jean-Louis; Yin Xindao; Toumoulin, Christine

    2013-01-01

    In abdomen computed tomography (CT), repeated radiation exposures are often inevitable for cancer patients who receive surgery or radiotherapy guided by CT images. Low-dose scans should thus be considered in order to avoid the harm of accumulative x-ray radiation. This work is aimed at improving abdomen tumor CT images from low-dose scans by using a fast dictionary learning (DL) based processing. Stemming from sparse representation theory, the proposed patch-based DL approach allows effective suppression of both mottled noise and streak artifacts. The experiments carried out on clinical data show that the proposed method brings encouraging improvements in abdomen low-dose CT images with tumors. (paper)

  2. Efficacy of Low-Dose Protocol in Follow-Up of Lymphoproliferative Disorders - Preliminary Results

    International Nuclear Information System (INIS)

    Popic-Ramac, J.; Brnic, Z.; Klasic, B.; Hebrang, A.; Knezevic, Z.

    2011-01-01

    Most medically-related radiation is caused by diagnostic examinations, in particular by computed tomography (CT). The purpose of this research is to reduce radiation doses faced by the population frequently exposed to such procedures-those with lymphoproliferative disorders. The research was conducted comparing radiation-exposition doses received by the radiosensitive organs (thyroid, lens, breast and gonad) using the standard thoracic CT protocol with the radiation received using the low-dose protocol, while maintaining display quality. The standard-dose thoracic protocol implies 120 kV and 150 mAs. The low-dose protocol was conducted on the same device using 120 kV and 30 mAs. We confirmed the hypothesis that the use of the low-dose thoracic CT protocol leads to a reduction in radiation dose without compromising display quality. It is further expected that a reduction in doses will reduce the risk of radiation-related mutations. (author)

  3. Long term effects of low doses of ionising radiation: facts and fallacies

    International Nuclear Information System (INIS)

    Iyer, G.K.

    1993-01-01

    Health effects of low doses of ionising radiation have been a public concern. The public perception of these low effects is that it causes cancer and genetic effects. Enormous amount of work regarding this cancer has been done all over the world, on occupational workers exposed to low doses of ionising radiation. These studies do not show any adverse effect on them. Epidemiological studies done on members of public staying near nuclear facilities also have shown that there is no health risk involved in staying near these facilities. Genetic effects have also shown negative results. These two aspects of health effects of low dose of radiation are discussed in detail. (author). 5 refs., 1 tab

  4. Low doses of ionizing radiation to mammalian cells may rather control than cause DNA damage

    Energy Technology Data Exchange (ETDEWEB)

    Feinendegen, L.E. [Brookhaven National Lab., Upton, NY (United States). Medical Dept.; Bond, V.P. [Washington State Univ., Richland, WA (United States); Sondhaus, C.A. [Univ. of Arizona, Tucson, AZ (United States). Dept. of Radiology and Radiation Control Office; Altman, K.I. [Univ. of Rochester Medical Center, NY (United States). Dept. of Biochemistry and Biophysics

    1998-12-31

    This report examines the origin of tissue effects that may follow from different cellular responses to low-dose irradiation, using published data. Two principal categories of cellular responses are considered. One response category relates to the probability of radiation-induced DNA damage. The other category consists of low-dose induced metabolic changes that induce mechanisms of DNA damage mitigation, which do not operate at high levels of exposure. Modeled in this way, tissue is treated as a complex adaptive system. The interaction of the various cellular responses results in a net tissue dose-effect relation that is likely to deviate from linearity in the low-dose region. This suggests that the LNT hypothesis should be reexamined. This paper aims at demonstrating tissue effects as an expression of cellular responses, both damaging and defensive, in relation to the energy deposited in cell mass, by use of microdosimetric concepts.

  5. Hypersensitivity to contrast media and dyes.

    Science.gov (United States)

    Brockow, Knut; Sánchez-Borges, Mario

    2014-08-01

    This article updates current knowledge on hypersensitivity reactions to diagnostic contrast media and dyes. After application of a single iodinated radiocontrast medium (RCM), gadolinium-based contrast medium, fluorescein, or a blue dye, a hypersensitivity reaction is not a common finding; however, because of the high and still increasing frequency of those procedures, patients who have experienced severe reactions are nevertheless frequently encountered in allergy departments. Evidence on allergologic testing and management is best for iodinated RCM, limited for blue dyes, and insufficient for fluorescein. Skin tests can be helpful in the diagnosis of patients with hypersensitivity reactions to these compounds. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Cutaneous drug hypersensitivity : Immunological and genetic perspective

    Directory of Open Access Journals (Sweden)

    Kisalay Ghosh

    2011-01-01

    Full Text Available Drug hypersensitivity is an unpredictable, immunologically mediated adverse reaction, clustered in a genetically predisposed individual. The role of "hapten concept" in immune sensitization has recently been contested by the "pharmacological interaction" hypothesis. After completion of the "human genome project" and with the availability of high-resolution genotyping, genetic susceptibility to hypersensitivity for certain drugs has been proved beyond doubt though the trend is ethnicity and phenotype dependent. Application of this newly acquired knowledge may reduce or abolish the morbidity and mortality associated with cutaneous drug hypersensitivity.

  7. Low-dose aspirin and risk of intracranial bleeds: An observational study in UK general practice.

    Science.gov (United States)

    Cea Soriano, Lucía; Gaist, David; Soriano-Gabarró, Montse; Bromley, Susan; García Rodríguez, Luis A

    2017-11-28

    To quantify the risk of intracranial bleeds (ICBs) associated with new use of prophylactic low-dose aspirin using a population-based primary care database in the United Kingdom. A cohort of new users of low-dose aspirin (75-300 mg; n = 199,079) aged 40-84 years and a 1:1 matched cohort of nonusers of low-dose aspirin at baseline were followed (maximum 14 years, median 5.4 years) to identify incident cases of ICB, with validation by manual review of patient records or linkage to hospitalization data. Using 10,000 frequency-matched controls, adjusted rate ratios (RRs) with 95% confidence intervals (CIs) were calculated for current low-dose aspirin use (0-7 days before the index date [ICB date for cases, random date for controls]); reference group was never used. There were 1,611 cases of ICB (n = 743 for intracerebral hemorrhage [ICH], n = 483 for subdural hematoma [SDH], and n = 385 for subarachnoid hemorrhage [SAH]). RRs (95% CI) were 0.98 (0.84-1.13) for all ICB, 0.98 (0.80-1.20) for ICH, 1.23 (0.95-1.59) for SDH, and 0.77 (0.58-1.01) for SAH. No duration of use or dose-response association was apparent. RRs (95% CI) for ≥1 year of low-dose aspirin use were 0.90 (0.72-1.13) for ICH, 1.20 (0.91-1.57) for SDH, and 0.69 (0.50-0.94) for SAH. Low-dose aspirin is not associated with an increased risk of any type of ICB and is associated with a significantly decreased risk of SAH when used for ≥1 year. © 2017 American Academy of Neurology.

  8. Data integration reveals key homeostatic mechanisms following low dose radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Tilton, Susan C.; Matzke, Melissa M. [Computational Biology and Bioinformatics, Pacific Northwest National Laboratory, Richland, WA 99338 (United States); Sowa, Marianne B.; Stenoien, David L.; Weber, Thomas J. [Health Impacts and Exposure Science, Pacific Northwest National Laboratory, Richland, WA 99338 (United States); Morgan, William F. [Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99338 (United States); Waters, Katrina M., E-mail: katrina.waters@pnnl.gov [Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99338 (United States)

    2015-05-15

    The goal of this study was to define pathways regulated by low dose radiation to understand how biological systems respond to subtle perturbations in their environment and prioritize pathways for human health assessment. Using an in vitro 3-D human full thickness skin model, we have examined the temporal response of dermal and epidermal layers to 10 cGy X-ray using transcriptomic, proteomic, phosphoproteomic and metabolomic platforms. Bioinformatics analysis of each dataset independently revealed potential signaling mechanisms affected by low dose radiation, and integrating data shed additional insight into the mechanisms regulating low dose responses in human tissue. We examined direct interactions among datasets (top down approach) and defined several hubs as significant regulators, including transcription factors (YY1, MYC and CREB1), kinases (CDK2, PLK1) and a protease (MMP2). These data indicate a shift in response across time — with an increase in DNA repair, tissue remodeling and repression of cell proliferation acutely (24–72 h). Pathway-based integration (bottom up approach) identified common molecular and pathway responses to low dose radiation, including oxidative stress, nitric oxide signaling and transcriptional regulation through the SP1 factor that would not have been identified by the individual data sets. Significant regulation of key downstream metabolites of nitrative stress was measured within these pathways. Among the features identified in our study, the regulation of MMP2 and SP1 was experimentally validated. Our results demonstrate the advantage of data integration to broadly define the pathways and networks that represent the mechanisms by which complex biological systems respond to perturbation. - Highlights: • Low dose ionizing radiation altered homeostasis in 3D skin tissue model. • Global gene/protein/metabolite data integrated using complementary statistical approaches • Time and location-specific change in matrix regulation

  9. 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.

  10. Low dose diagnostic radiation does not increase cancer risk in cancer prone mice

    Energy Technology Data Exchange (ETDEWEB)

    Boreham, D., E-mail: dboreham@nosm.ca [Northern Ontario School of Medicine, ON (Canada); Phan, N., E-mail: nghiphan13@yahoo.com [Univ. of Ottawa, Ottawa, ON (Canada); Lemon, J., E-mail: lemonja@mcmaster.ca [McMaster Univ., Hamilton, ON (Canada)

    2014-07-01

    The increased exposure of patients to low dose diagnostic ionizing radiation has created concern that these procedures will result in greater risk of carcinogenesis. However, there is substantial evidence that shows in many cases that low dose exposure has the opposite effect. We have investigated whether CT scans can modify mechanisms associated with carcinogenesis in cancer-prone mice. Cancer was induced in Trp53+/- mice with an acute high dose whole-body 4 Gy γ-radiation exposure. Four weeks following the cancer-inducing dose, weekly whole-body CT scans (10 mGy/scan, 75 kVp X-rays) were given for ten consecutive weeks adding an additional radiation burden of 0.1 Gy. Short-term biological responses and subsequent lifetime cancer risk were investigated. Five days following the last CT scan, there were no detectable differences in the spontaneous levels of DNA damage in blood cells (reticulocytes). In fact, CT scanned mice had significantly lower constitutive levels of oxidative DNA damage and cell death (apoptosis), compared to non-CT scanned mice. This shows that multiple low dose radiation exposures modified the radio response and indicates protective processes were induced in mice. In mice treated with the multiple CT scans following the high cancer-inducing 4 Gy dose, tumour latency was increased, significantly prolonging lifespan. We conclude that repeated CT scans can reduce the cancer risk of a prior high-dose radiation exposure, and delay the progression of specific types of radiation-induced cancers in Trp53+/-mice. This research shows for the first time that low dose exposure long after cancer initiation events alter risk and reduce cancer morbidity. Cancer induction following low doses does not follow a linear non-threshold model of risk and this model should not be used to extrapolate risk to humans following low dose exposure to ionizing radiation. (author)

  11. Response of human and rabbit lymphocytes to low doses of X-rays

    International Nuclear Information System (INIS)

    Fabry, L.

    1982-01-01

    The response of human and rabbit lymphocytes to low doses of X-rays was studied by the yields of dicentrics in first division metaphases. For both species, the dose-response curve was best fitted to the linear-quadratic model with a linear component predominating up to 67 and 42 rad respectively for man and rabbit. A calibration curve (5-400 rad) was obtained by combining the present results on man with previous data at higher doses. On the other hand, it appears that, at low doses, the radiosentivity of human lymphocytes is significantly higher than that of rabbit lymphocytes [fr

  12. Bleeding Risk with Long-Term Low-Dose Aspirin: A Systematic Review of Observational Studies

    Science.gov (United States)

    García Rodríguez, Luis A.; Martín-Pérez, Mar; Hennekens, Charles H.; Rothwell, Peter M.; Lanas, Angel

    2016-01-01

    Background Low-dose aspirin has proven effectiveness in secondary and primary prevention of cardiovascular events, but is also associated with an increased risk of major bleeding events. For primary prevention, this absolute risk must be carefully weighed against the benefits of aspirin; such assessments are currently limited by a lack of data from general populations. Methods Systematic searches of Medline and Embase were conducted to identify observational studies published between 1946 and 4 March 2015 that reported the risks of gastrointestinal (GI) bleeding or intracranial hemorrhage (ICH) with long-term, low-dose aspirin (75–325 mg/day). Pooled estimates of the relative risk (RR) for bleeding events with aspirin versus non-use were calculated using random-effects models, based on reported estimates of RR (including odds ratios, hazard ratios, incidence rate ratios and standardized incidence ratios) in 39 articles. Findings The incidence of GI bleeding with low-dose aspirin was 0.48–3.64 cases per 1000 person-years, and the overall pooled estimate of the RR with low-dose aspirin was 1.4 (95% confidence interval [CI]: 1.2–1.7). For upper and lower GI bleeding, the RRs with low-dose aspirin were 2.3 (2.0–2.6) and 1.8 (1.1–3.0), respectively. Neither aspirin dose nor duration of use had consistent effects on RRs for upper GI bleeding. The estimated RR for ICH with low-dose aspirin was 1.4 (1.2–1.7) overall. Aspirin was associated with increased bleeding risks when combined with non-steroidal anti-inflammatory drugs, clopidogrel and selective serotonin reuptake inhibitors compared with monotherapy. By contrast, concomitant use of proton pump inhibitors decreased upper GI bleeding risks relative to aspirin monotherapy. Conclusions The risks of major bleeding with low-dose aspirin in real-world settings are of a similar magnitude to those reported in randomized trials. These data will help inform clinical judgements regarding the use of low-dose aspirin

  13. Low-dose radiotherapy as treatment for benign lymphoepitelial lesion in HIV-patients

    International Nuclear Information System (INIS)

    Gonzalez Patino, E.; Lopez Vazquez, M.D.; Cascallar Caneda, L.; Antinez Lopez, J.; Victoria Fernandez, C.; Salvador Garrido, N.; Ares Banobre, M.; Porto vazquez, M.C.

    1995-01-01

    Standard treatments for benign lymphoepitelial lesion of the parotid gland in patients infected with the human immunodeficiency virus (HIV) are unsatisfactory. Recently, low-dose radiotherapy has been proposed as a noninvasive treatment option. We describe a case of bilateral benign lymphoepitelial lesion parotid gland in a HIV-positive paint, treated by radiotherapy. Low-dose radiotherapy, appears as a alternative in the treatment for benign lymphoepitelial lesion in HIV-patients, and preliminary evaluations have indicated that this treatment is effective from both the clinical and cosmetic points of view

  14. Intraocular levels of methotrexate after oral low-dose treatment in chronic uveitis.

    Science.gov (United States)

    Puchta, Joachim; Hattenbach, Lars-Olof; Baatz, Holger

    2005-01-01

    To determine the intraocular levels of methotrexate in low-dose treatment of noninfectious uveitis. One day after oral administration, the methotrexate level was measured in the aqueous humor and serum of a patient with noninfectious uveitis, who underwent cataract surgery. A fluorescence polarization immunoassay was used for determination. After oral administration, methotrexate was only measurable in aqueous humor but not in serum. In uveitis, orally administered low-dose methotrexate reaches detectable levels in aqueous humor, even in the absence of detectable levels in serum. Copyright (c) 2005 S. Karger AG, Basel.

  15. Treatment of Complex Regional Pain Syndrome (CRPS) using low dose naltrexone (LDN).

    Science.gov (United States)

    Chopra, Pradeep; Cooper, Mark S

    2013-06-01

    Complex Regional Pain Syndrome (CRPS) is a neuropathic pain syndrome, which involves glial activation and central sensitization in the central nervous system. Here, we describe positive outcomes of two CRPS patients, after they were treated with low-dose naltrexone (a glial attenuator), in combination with other CRPS therapies. Prominent CRPS symptoms remitted in these two patients, including dystonic spasms and fixed dystonia (respectively), following treatment with low-dose naltrexone (LDN). LDN, which is known to antagonize the Toll-like Receptor 4 pathway and attenuate activated microglia, was utilized in these patients after conventional CRPS pharmacotherapy failed to suppress their recalcitrant CRPS symptoms.

  16. Effects of low-dose recombinant human erythropoietin treatment on cognitive performance

    DEFF Research Database (Denmark)

    Viuff, Søren Lundgaard; Plenge, Ulla; Belhage, Bo

    2017-01-01

    , NUFI or self-reported results between the groups. CONCLUSIONS: In this small study, we found no significant effect of low-dose or micro-dose rhEpo on visual attention, cognitive performance in complex cognitive tasks or self-experienced cognitive performance compared with placebo. FUNDING: The Aase......INTRODUCTION: High-dose recombinant human erythropoietin (rhEpo) has been shown to improve cognitive performance in both healthy volunteers and in patients suffering from diseases affecting the brain. The aim of this study was to examine whether administration of low-dose and even micro-dose rh...

  17. Effects of low-dose recombinant human erythropoietin treatment on cognitive performance

    DEFF Research Database (Denmark)

    Viuff, Søren Lundgaard; Plenge, Ulla; Belhage, Bo

    2017-01-01

    -reported results between the groups. Conclusions: In this small study, we found no significant effect of low-dose or micro-dose rhEpo on visual attention, cognitive performance in complex cognitive tasks or self-experienced cognitive performance compared with placebo. Funding: The Aase and Ejnar Danielsen......Introduction: High-dose recombinant human erythropoietin (rhEpo) has been shown to improve cognitive performance in both healthy volunteers and in patients suffering from diseases affecting the brain. The aim of this study was to examine whether administration of low-dose and even micro-dose rh...

  18. Effects of low doses of alcohol on declarative memory in humans

    Directory of Open Access Journals (Sweden)

    José Arturo Bríñez-Horta

    2011-09-01

    Full Text Available This study assessed the effect of low doses of alcohol on two elements of explicit or declarative memory, in 16 participants, 8 women and 8 men, with The Weschler Memory Scale III Text Test. A factorial 2 * 4 counterbalanced with repeated measures design was used. There were no statistically significant differences by gender, but there were differences among doses, specially 0.150 g / Kg., which reduced episodic and semantic retrieval, between 43.9 and 62.9 % of effect strength, in intermediate term memory. These results provided evidence that alcohol in low doses has a more pronounced effect in semantic, rather than episodic memory, in the middle term

  19. Study on mechanism of decreased lipid peroxide by low dose radiation

    International Nuclear Information System (INIS)

    Yamaoka, Kiyonori; Okazoe, Yoko; Akimaru, Kunihiro; Sato, E.F.; Utsumi, Kozo.

    1991-01-01

    We examined the effect of SOD on lipid peroxidation in biomembrane from V.E-deficient rats, in order to study the mechanism of increased SOD activities and decreased lipid peroxide by low dose irradiation. The following results were obtained. i. Active oxygen (O 2 - ) strongly enhances lipid peroxidations in biomembrane with the Fe 3+ as catalyst. ii. SOD evidently inhibits lipid peroxidations under above conditions. iii. We suggested that the effect of SOD enhanced by low dose irradiation results in inhibition of lipid peroxidation. (author)

  20. Clinical characteristic of epidemic hepatitis in case of the effect of low dose irradiation

    International Nuclear Information System (INIS)

    Geras'kov, O.P.; Shubik, V.M.

    1990-01-01

    Clinical course of infections hepatitics B, developed on the background of pulmonary tuberculosis in people, who were subjected to chronic low dose ionizing radiation, indicated more frequent cases of severe and medium-severe forms of morbidity as compared to non-irradiated patients and those with no comitant pulmonary tuberculosis. However the reconvalescence terms, hepatitis size normalization, urine colour in different group patients did not differ essentially. The data obtained testify to the absence of significant peculiarities in the course of infections hepatitis B, combined with pulmonar tuberculosis under conditions of chronic low dose ionizing radiation. 3 refs.; 3 tabs

  1. The interaction of platinum complexes with low doses of X-rays in hypoxic cells

    International Nuclear Information System (INIS)

    Skov, K.A.

    1992-01-01

    It is not clear why electron affinic compounds (O2, nitroimidazoles) should be more effective sensitizers at high doses (modify double events, 6, 16) while platinum complexes interact to a greater extent at low doses (modification of single-events). The possibility that crosslinks are involved requires further consideration. While DNA intrastrand crosslinks do not appear essential, future low dose experiments are planned to determine the role of interstrand and DNA-protein crosslinks in modifying response at clinical doses. (author). 31 refs., 2 tabs

  2. Mechanism of suppressive effect of low dose radiation on cancer cell dissemination in mice

    International Nuclear Information System (INIS)

    Fu Haiqing; Li Xiuyi; Chen Yubing; Zhang Yingchun; Liu Shuzheng

    1997-01-01

    Influence of low dose radiation on immunity in C57 BL/6 mice injected with cancer cells was studied. In mice given 75 mGy WBI 24 h before injection of Lewis lung carcinoma cells or B 16 melanoma cells, the percentage of S-phase thymocytes and CD 3+ thymocytes, the splenic NK cell activity, IL-2 secretion and γIFN secretion were found to be potentiated 2∼8 day after irradiation in comparison with the sham-irradiation mice. The results suggest that low dose radiation might suppress cancer cell dissemination via the enhancement of immune reactivity

  3. Randomized phase 2 study of low-dose decitabine vs low-dose azacitidine in lower-risk MDS and MDS/MPN.

    Science.gov (United States)

    Jabbour, Elias; Short, Nicholas J; Montalban-Bravo, Guillermo; Huang, Xuelin; Bueso-Ramos, Carlos; Qiao, Wei; Yang, Hui; Zhao, Chong; Kadia, Tapan; Borthakur, Gautam; Pemmaraju, Naveen; Sasaki, Koji; Estrov, Zeev; Cortes, Jorge; Ravandi, Farhad; Alvarado, Yesid; Komrokji, Rami; Sekeres, Mikkael A; Steensma, David P; DeZern, Amy; Roboz, Gail; Kantarjian, Hagop; Garcia-Manero, Guillermo

    2017-09-28

    Hypomethylating agents (HMAs) improve survival in patients with higher-risk myelodysplastic syndromes (MDS) but are less well-studied in lower-risk disease. We compared the safety and efficacy of low-dose decitabine vs low-dose azacitidine in this group of patients. Adults with low- or intermediate 1-risk MDS or MDS/myeloproliferative neoplasm (MPN), including chronic myelomonocytic leukemia, according to the International Prognostic Scoring System, were randomly assigned using a Bayesian adaptive design to receive either azacitidine 75 mg/m 2 intravenously/subcutaneously daily or decitabine 20 mg/m 2 intravenously daily for 3 consecutive days on a 28-day cycle. The primary outcome was overall response rate (ORR). Between November 2012 and February 2016, 113 patients were treated: 40 (35%) with azacitidine and 73 (65%) with decitabine. The median age was 70 years; 81% of patients were intermediate 1-risk patients. The median number of cycles received was 9. The ORRs were 70% and 49% ( P = .03) for patients treated with decitabine and azacitidine, respectively. Thirty-two percent of patients treated with decitabine became transfusion independent compared with 16% of patients treated with azacitidine ( P = .2). Cytogenetic response rates were 61% and 25% ( P = .02), respectively. With a median follow-up of 20 months, the overall median event-free survival was 18 months: 20 and 13 months for patients treated with decitabine and azacitidine, respectively ( P = .1). Treatment was well tolerated, with a 6-week mortality rate of 0%. The use of low-dose HMAs is safe and effective in patients with lower-risk MDS and MDS/MPN. Their effect on the natural history of lower-risk disease needs to be further studied. This trial was registered at clinicaltrials.gov (identifier NCT01720225). © 2017 by The American Society of Hematology.

  4. Evaluation of a combination of low-dose ketamine and low-dose midazolam in terminal dyspnea-attenuation of "double-effect"

    Directory of Open Access Journals (Sweden)

    Abhijit Kanti Dam

    2008-01-01

    Full Text Available Aim: Of all symptoms in palliative medicine those concerning respiration are most excruciating and difficult to treat. Reticence about the use of morphine for palliation of dyspnea is common, especially in nonmalignant diseases, as there is a fear of causing respiratory depression, particularly where Chronic Obstructive Pulmonary Disease (COPD exists. This factor is also compounded by the lack of availability of morphine in parts of developing countries. Ketamine has excellent anesthetic and analgesic effects in addition to being easily available. It produces bronchodilatation and does not produce respiratory or cardiovascular depression. The author seeks to evaluate the role of low-dose (0.2 mg/kg ketamine and midazolam (0.02 mg/kg in the attenuation of terminal dyspnea. Methods: Sixteen patients with terminal dyspnea, admitted to the Critical Care Unit (CCU with cancer and other noncancer diagnoses were recruited. The subjective component of dyspnea was assessed using the Graphic Rating Scale (GRS, which has values from 0 - 10, 10 being maximum dyspnea. Each patient received a low-dose of ketamine and midazolam for relief of dyspnea. All the patients received low-flow (2 L/min. oxygen therapy via nasal cannula. Immediately after admission, all the patients were reassured and nursed in a decubitus position of their choice. The GRS was recorded at the point of admission, 10 minutes after starting oxygen therapy, and ten minutes after administration of low-dose ketamine and midazolam. Hemodynamic parameters were also recorded at these three points. Result: All the patients who enrolled in our study had significant dyspnea at admission, as was evident from the GRS scores of 8.250 (SD 0.91, respiratory rate of 28.56 (SD 5.0, mean arterial blood pressure (MABP of 102.7 (SD 14.63, pulse rate of 115.62 (SD 23.3, and SpO2 of 92.43 (SD 2.38. All the patients benefited from the combination of ketamine and midazolam, as evidenced by the statistically

  5. Immediate-type hypersensitivity to polyethylene glycols

    DEFF Research Database (Denmark)

    Wenande, E; Garvey, L H

    2016-01-01

    Polyethylene glycols (PEGs) or macrogols are polyether compounds widely used in medical and household products. Although generally considered biologically inert, cases of mild to life-threatening immediate-type PEG hypersensitivity are reported with increasing frequency. Nevertheless, awareness...

  6. Classification and pathophysiology of radiocontrast media hypersensitivity.

    Science.gov (United States)

    Brockow, Knut; Ring, Johannes

    2010-01-01

    Hypersensitivity reactions to radiocontrast media (RCM) are unpredictable and are a concern for radiologists and cardiologists. Immediate hypersensitivity reactions manifest as anaphylaxis, and an allergic IgE-mediated mechanism has been continuously discussed for decades. Non-immediate reactions clinically are exanthemas resembling other drug-induced non-immediate hypersensitivities. During the past years, evidence is increasing that some of these reactions may be immunological. Repeated reactions after re-exposure, positive skin tests, and presence of specific IgE antibodies as well as positive basophil activation tests in some cases, and positive lymphocyte transformation or lymphocyte activation tests in others, indicate that a subgroup of both immediate and non-immediate reactions are of an allergic origin, although many questions remain unanswered. Recently reported cases highlight that pharmacological premedication is not safe to prevent RCM hypersensitivity in patients with previous severe reactions. These insights may have important consequences. A large multicenter study on the value of skin tests in RCM hypersensitivity concluded that skin testing is a useful tool for diagnosis of RCM allergy. It may have a role for the selection of a safe product in previous reactors, although confirmatory validation data is still scarce. In vitro tests to search for RCM-specific cell activation still are in development. In conclusion, recent data indicate that RCM hypersensitivity may have an allergic mechanism and that allergological testing is useful and may indicate tolerability. Copyright 2010 S. Karger AG, Basel.

  7. Safety and efficacy of low-dose, subacute exposure of mature ewes to sodium chlorate

    Science.gov (United States)

    The objective was to determine the safety and efficacy of low-dose, subacute exposure of mature ewes to NaClO3 in the drinking water. Twenty-five ewes (BW = 62.5 ± 7.3 kg) were placed indoors in individual pens with ad libitum access to water and feed. After 7 d of adaptation, ewes were assigned ran...

  8. Determination of line edge roughness in low-dose top-down scanning electron microscopy images

    NARCIS (Netherlands)

    Verduin, T.; Kruit, P.; Hagen, C.W.

    2014-01-01

    We investigated the off-line metrology for line edge roughness (LER) determination by using the discrete power spectral density (PSD). The study specifically addresses low-dose scanning electron microscopy (SEM) images in order to reduce the acquisition time and the risk of resist shrinkage. The

  9. Effects of low dose gamma- and UV-radiation on sea urchin eggs and spermatozoa

    International Nuclear Information System (INIS)

    Czihak, G.K.

    1991-01-01

    The paper outlines the results of a study of the effects of low dose gamma-and UV-irradiation on sea urchin eggs and spermatozoa with particular reference to the effects on the stages of the mitotic cycle and individual susceptibility. (UK)

  10. Bioassay in BALB/c mice exposed to low dose rate radiation

    Energy Technology Data Exchange (ETDEWEB)

    Km, Sung Dae; Gong, Eun Ji; Bae, Min Ji; Yang, Kwang Mo; Kim, Joong Sun [Dongnam Institute of Radiological and Medical Sciences, Suwon (Korea, Republic of)

    2012-09-15

    The present study was performed to investigate the toxicity of low-dose-rate irradiation in BALB/c mice. Twenty mice of each sex were randomly assigned to four groups of five mice each and were exposed to 0 (sham), 0.02, 0.2, or 2 Gy, equivalents to low-dose-rate irradiation to 3.49 mGy{center_dot}h{sup -1}. Urine, blood, and blood biochemistry were analyzed, and organ weight was measured. The low-dose-rate irradiation did not induce any toxicologically significant changes in mortality, clinical signs, body weight, food and water consumption, urinalysis, and serum biochemistry. However, the weights of reproductive organs including the testis, ovary, and uterus decreased in a dose-dependent manner. Irradiation at 2 Gy significantly decreased the testis, ovary, and uterus weights, but did not change the weights of other organs. There were no adverse effects on hematology in any irradiated group and only the number of neutrophils increased dose dependently. The low-dose-rate irradiation exposure did not cause adverse effects in mice at dose levels of 2 Gy or less, but the reproductive systems of male and female mice showed toxic effects.

  11. Cytogenetics dosimetry: dose-response curve for low doses of X-ray

    International Nuclear Information System (INIS)

    Lara, Virginia E. Noval; Pineda Bolivar, William R.; Riano, Victor M. Pabon; Ureana, Cecilia Crane

    2013-01-01

    The purpose of this study was to conduct a preliminary study for the standardization in the future, the dose-response curve for low doses of X-rays, through the analysis of in vitro cultures of peripheral blood samples of 3 men and 3 women occupationally not exposed to artificial sources of ionizing radiation, age 18-40 years, where possible nonsmokers

  12. Low-dose ionizing radiation – is it harmful to health?

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, A. H. [CERN Radiation Protection Group (European Organization for Nuclear Research (CERN))

    1987-09-15

    A conference on the health effects of low-dose ionizing radiation organized in London earlier this year by the British Nuclear Energy Society brought together epidemiologists who have been investigating the mortality of workers from the nuclear industry in an attempt to put low-level radiation risk estimates on a scientific basis.

  13. Mammalian Tissue Response to Low Dose Ionizing Radiation: The Role of Oxidative Metabolism and Intercellular Communication

    Energy Technology Data Exchange (ETDEWEB)

    Azzam, Edouard I

    2013-01-16

    The objective of the project was to elucidate the mechanisms underlying the biological effects of low dose/low dose rate ionizing radiation in organs/tissues of irradiated mice that differ in their susceptibility to ionizing radiation, and in human cells grown under conditions that mimic the natural in vivo environment. The focus was on the effects of sparsely ionizing cesium-137 gamma rays and the role of oxidative metabolism and intercellular communication in these effects. Four Specific Aims were proposed. The integrated outcome of the experiments performed to investigate these aims has been significant towards developing a scientific basis to more accurately estimate human health risks from exposures to low doses ionizing radiation. By understanding the biochemical and molecular changes induced by low dose radiation, several novel markers associated with mitochondrial functions were identified, which has opened new avenues to investigate metabolic processes that may be affected by such exposure. In particular, a sensitive biomarker that is differentially modulated by low and high dose gamma rays was discovered.

  14. Low-Dose Radiation Exposure and Atherosclerosis in ApoE(-/-) Mice

    NARCIS (Netherlands)

    Mitchel, R. E. J.; Hasu, M.; Bugden, M.; Wyatt, H.; Little, M. P.; Gola, A.; Hildebrandt, G.; Priest, N. D.; Whitman, S. C.

    The hypothesis that single low-dose exposures (0.025-0.5 Gy) to low-LET radiation given at either high (about 150 mGy/min) or low (1 mGy/min) dose rate would promote aortic atherosclerosis was tested in female C57BL/6J mice genetically predisposed to this disease (ApoE(-/-)). Mice were exposed

  15. The effect of Low-dose Gamma Radiation on the Bio-chemical ...

    African Journals Online (AJOL)

    Low-dose gamma radiation has been applied to intravenous fluids to enhance the sterility assurance levels. This study was undertaken to determine the stability of gamma irradiated 2.5 % dextrose, 2.5 % dextrose in saline, Ringers lactate and Gastrointestinal replacement fluid at doses of 0, 2, 4, 6, 8, 10 and 20 kGy.

  16. Effect of low dose Lead (Pb) administration on tail immersion test ...

    African Journals Online (AJOL)

    Effect of low dose Lead (Pb) administration on tail immersion test and ... subtle decline in cognitive function, and adverse reproductive outcome at low blood Pb level. ... Twenty adult Wistar rats of both sexes (weight 150g to 200g) were used.

  17. Effect of Low-Dose MDCT and Iterative Reconstruction on Trabecular Bone Microstructure Assessment.

    Science.gov (United States)

    Kopp, Felix K; Holzapfel, Konstantin; Baum, Thomas; Nasirudin, Radin A; Mei, Kai; Garcia, Eduardo G; Burgkart, Rainer; Rummeny, Ernst J; Kirschke, Jan S; Noël, Peter B

    2016-01-01

    We investigated the effects of low-dose multi detector computed tomography (MDCT) in combination with statistical iterative reconstruction algorithms on trabecular bone microstructure parameters. Twelve donated vertebrae were scanned with the routine radiation exposure used in our department (standard-dose) and a low-dose protocol. Reconstructions were performed with filtered backprojection (FBP) and maximum-likelihood based statistical iterative reconstruction (SIR). Trabecular bone microstructure parameters were assessed and statistically compared for each reconstruction. Moreover, fracture loads of the vertebrae were biomechanically determined and correlated to the assessed microstructure parameters. Trabecular bone microstructure parameters based on low-dose MDCT and SIR significantly correlated with vertebral bone strength. There was no significant difference between microstructure parameters calculated on low-dose SIR and standard-dose FBP images. However, the results revealed a strong dependency on the regularization strength applied during SIR. It was observed that stronger regularization might corrupt the microstructure analysis, because the trabecular structure is a very small detail that might get lost during the regularization process. As a consequence, the introduction of SIR for trabecular bone microstructure analysis requires a specific optimization of the regularization parameters. Moreover, in comparison to other approaches, superior noise-resolution trade-offs can be found with the proposed methods.

  18. A long-term risk-benefit analysis of low-dose aspirin in primary prevention.

    Science.gov (United States)

    Wu, I-Chen; Hsieh, Hui-Min; Yu, Fang-Jung; Wu, Meng-Chieh; Wu, Tzung-Shiun; Wu, Ming-Tsang

    2016-02-01

    The long-term risk-benefit effect of occasional and regular use of low-dose aspirin (≤ 100 mg per day) in primary prevention of vascular diseases and cancers was calculated. One representative database of 1 000 000 participants from Taiwan's National Health Insurance scheme in 1997-2000 was used. The potential study subjects were those aged 30-95 years, were found not to have been prescribed aspirin before 1 January 2000, but to have first been prescribed low-dose aspirin (≤ 100 mg per day) after that date and were followed up to 31 December 2009. Participants prescribed low-dose aspirin risk. A total of 1720 pairs were analysed. During the study period, haemorrhage and ischaemia occurred in 25 (1·45%) and 67 participants (3·90%) in occasional users and 69 (4·01%) and 100 participants (5·81%) in regular users, whereas cancer occurred in 32 participants (1·86%) in occasional users and 26 participants (1·51%) in regular users. The crude and adjusted net clinical risks of low-dose aspirin use between the two frequency of users (≥ 80% vs. prevention against major vascular diseases and cancer. © 2015 Stichting European Society for Clinical Investigation Journal Foundation.

  19. Low doses of ionizing radiation: Biological effects and regulatory control. Contributed papers

    International Nuclear Information System (INIS)

    1997-11-01

    The International Atomic Energy Agency and the World Health Organization, in cooperation with the United Nations Scientific Committee on the Effects of Atomic Radiation, organized an international conference on Low Doses of Ionizing Radiation: Biological Effects and Regulatory Control, held in seville, Spain, from 17 to 21 November 1997. This technical document contains concise papers submitted to the conference

  20. Low doses of ionizing radiation: Biological effects and regulatory control. Contributed papers

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-11-01

    The International Atomic Energy Agency and the World Health Organization, in cooperation with the United Nations Scientific Committee on the Effects of Atomic Radiation, organized an international conference on Low Doses of Ionizing Radiation: Biological Effects and Regulatory Control, held in seville, Spain, from 17 to 21 November 1997. This technical document contains concise papers submitted to the conference. Refs, figs, tabs.

  1. Methotrexate osteopathy in long-term, low-dose methotrexate treatment for psoriasis and rheumatoid arthritis

    NARCIS (Netherlands)

    Zonneveld, I. M.; Bakker, W. K.; Dijkstra, P. F.; Bos, J. D.; van Soesbergen, R. M.; Dinant, H. J.

    1996-01-01

    In dermatology and rheumatology, methotrexate is frequently prescribed in low dosages per week; in oncology, high dosages per week are prescribed. Methotrexate osteopathy was first reported in children with leukemia treated with high doses of methotrexate. In animal studies, low doses of

  2. Low-dose aspirin and rupture of abdominal aortic aneurysm

    DEFF Research Database (Denmark)

    Wemmelund, Holger; Jørgensen, Trine M M; Høgh, Annette

    2016-01-01

    OBJECTIVE: The use of low-dose aspirin (acetylsalicylic acid [ASA]) has been suggested to attenuate growth of abdominal aortic aneurysms (AAAs), yet solid clinical evidence of this hypothesis is still missing. This study aimed to investigate whether preadmission ASA use influenced the risk...

  3. Activation of chemical biological defense mechanisms and remission of vital oxidative injury by low dose radiation

    International Nuclear Information System (INIS)

    Yamaoka, K.; Nomura, T.; Kojima, S.

    2000-01-01

    Excessive active oxygen produced in vivo by various causes is toxic. Accumulation of oxidation injuries due to excessive active causes cell and tissue injuries, inducing various pathologic conditions such as aging and carcinogenesis. On the other hand, there are chemical defense mechanisms in the body that eliminate active oxygen or repair damaged molecules, defending against resultant injury. It is interesting reports that appropriate oxidation stress activate the chemical biological defense mechanisms. In this study, to elucidate these phenomena and its mechanism by low dose radiation, we studied on the below subjects. Activation of chemical biological defense mechanisms by low dose radiation: (1) The effects radiation on lipid peroxide (LPO) levels in the organs, membrane fluidity and the superoxide dismutase (SOD) activity were examined in rats and rabbits. Rats were irradiated with low dose X-ray over their entire bodies, and rabbits inhaled vaporized radon spring water, which primarily emitted α-ray. The following results were obtained. Unlike high dose X-ray, low dose X-ray and radon inhalation both reduced LPO levels and made the state of the SH-group on membrane-bound proteins closer to that of juvenile animals, although the sensitivity to radioactivity varied depending on the age of the animals and among different organs and tissues. The SOD activity was elevated, suggesting that low dose X-ray and radon both activate the host defensive function. Those changes were particularly marked in the organs related to immune functions of the animals which received low dose X-ray, while they were particularly marked in the brain after radon inhalation. It was also found that those changes continued for longer periods after low dose X-irradiation. (2) Since SOD is an enzyme that mediates the dismutation of O 2 - to H 2 O 2 , the question as to whether the resultant H 2 O 2 is further detoxicated into H 2 O and O 2 or not must still be evaluated. Hence, we studied

  4. Fully Convolutional Architecture for Low-Dose CT Image Noise Reduction

    Science.gov (United States)

    Badretale, S.; Shaker, F.; Babyn, P.; Alirezaie, J.

    2017-10-01

    One of the critical topics in medical low-dose Computed Tomography (CT) imaging is how best to maintain image quality. As the quality of images decreases with lowering the X-ray radiation dose, improving image quality is extremely important and challenging. We have proposed a novel approach to denoise low-dose CT images. Our algorithm learns directly from an end-to-end mapping from the low-dose Computed Tomography images for denoising the normal-dose CT images. Our method is based on a deep convolutional neural network with rectified linear units. By learning various low-level to high-level features from a low-dose image the proposed algorithm is capable of creating a high-quality denoised image. We demonstrate the superiority of our technique by comparing the results with two other state-of-the-art methods in terms of the peak signal to noise ratio, root mean square error, and a structural similarity index.

  5. The effects of low-dose radiotherapy on fresh osteochondral allografts: An experimental study in rabbits

    Directory of Open Access Journals (Sweden)

    Uğur Gönç

    2016-10-01

    Conclusion: In osteochondral massive allograft transplantations, the immune reaction of the host could be precluded with radiotherapy, and the side-effects can be prevented by low-dose fractionated regimen. The total dose of fractionated radiotherapy for an immune suppression should be adjusted not to damage the cartilage tissue, but to avoid articular degeneration in the long term.

  6. Low-Dose Adefovir-Induced Hypophosphatemic Osteomalacia on Whole-Body Bone Scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Hoon; Won, Kyoung Sook; Song, Bongil; Jo, Il; Zeon, Seok Kil [Keimyung Univ., Daegu (Korea, Republic of)

    2013-12-15

    While adefovir dipivoxil (ADV) effectively suppresses the hepatitis B virus, it can cause proximal renal tubular dysfunction leading to phosphate wasting. The safety of low-dose ADV (a dose of 10 mg/day), which does not induce clinically significant nephrotoxicity, is well recognized, but a few cases of hypophosphatemic osteomalacia (HO) caused by low-dose ADV therapy have recently been reported. Although HO induced by low-dose ADV therapy is rare, the presence of bone pain in patients treated with ADV should be monitored. Bone scintigraphy can be performed to confirm the occurrence of osteomalacia and to determine the disease extent. Bone scintigraphic and radiological image findings with a brief review of the literature are presented in this article. We report two cases of HO induced by low-dose ADV therapy that showed multifocal increased radiotracer uptakes in the bilateral bony ribs, spines, pelvic bones and lower extremities on whole-body bone scintigraphy. Bone pain gradually improved after phosphate supplementation and by changing the antiviral agent. Whole-body bone scintigraphy is a highly sensitive imaging tool and can show disease extent at once in the setting of the wide range of the clinical spectrum with nonspecific radiological findings. Furthermore, frequent involvement of the lower extremities, as a result of maximum weight bearing, could be an additional scintigraphic clue for the diagnosis of HO. These cases could be helpful for both clinicians prescribing ADV and nuclear physicians to prevent delayed diagnosis and plan further appropriate treatment.

  7. Stimulatory effect of low dose radionuclide on DNA synthesis and UDS in splenic lymphocytes

    International Nuclear Information System (INIS)

    Zhu Shoupeng; Yang Zhanshan

    1999-12-01

    To study the stimulatory effect on DNA synthesis and unscheduled DNA synthesis (UDS) in splenic lymphocytes induced by low dose enriched uranium 235 U. By using 3 H-TdR incorporation assay technique, the DNA replicative synthesis in PHA and LPS stimulated splenic lymphocytes was observed. By using DNA synthesis inhibitor such as hydroxyurea, the UV-induced unscheduled DNA synthesis in splenic lymphocytes occurred. When the injected low dose of enriched uranium 235 u was 0.1 μg/kg body weight, the transformation capacity was elevated for splenic T lymphocytes, simultaneously the stimulative index increased. The UDS of splenic lymphocytes induced by ultra-violate revealed a statistically significant increase by low dose of enriched uranium 235 U at the range of 0.1-20 μg/kg body weight. A stimulatory action of low dose enriched uranium 235 U on DNA replicative synthesis as well as on UV-induced UDS in splenic lymphocytes was detected

  8. Low dose spironolactone reduces blood pressure in patients with resistant hypertension and type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Stolzenburg Oxlund, Christina; Henriksen, J. E.; Tarnow, L.

    2013-01-01

    frequent adverse event leading to dose reduction in three cases and discontinuation in one, whereas gynaecomastia was not reported.Conclusion:Low dose spironolactone exerts significant BP and urinary albumin creatinine ratio lowering effects in high-risk patients with resistant hypertension and type 2...

  9. Tibolone and low-dose continuous combined hormone treatment : vaginal bleeding pattern, efficacy and tolerability

    NARCIS (Netherlands)

    Hammar, M. L.; van de Weijer, P.; Franke, H. R.; Pornel, B.; von Mauw, E. M. J.; Nijland, E. A.

    2007-01-01

    Objectives The primary objective was to compare the vaginal bleeding pattern during administration of tibolone and low-dose continuous combined estradiol plus norethisterone acetate (E-2/NETA). The secondary objectives were efficacy on vasomotor symptoms and vaginal atrophy. Design A randomised,

  10. Optimised low-dose multidetector CT protocol for children with cranial deformity

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez, Jose Luis [Complejo Hospitalario Universitario de Vigo, Department of Radiology, Vigo, Pontevedra (Spain); Pombar, Miguel Angel [Complejo Hospitalario Universitario de Santiago, Department of Radiophysics, Santiago de Compostela, La Coruna (Spain); Pumar, Jose Manuel [Complejo Hospitalario Universitario de Santiago, Department of Radiology, Santiago de Compostela, La Coruna (Spain); Campo, Victor Miguel del [Complejo Hospitalario Universitario de Vigo, Department of Public Health, Vigo, Pontevedra (Spain)

    2013-08-15

    To present an optimised low-dose multidetector computed tomography (MDCT) protocol for the study of children with cranial deformity. Ninety-one consecutive MDCT studies were performed in 80 children. Studies were performed with either our standard head CT protocol (group 1, n = 20) or a low-dose cranial deformity protocol (groups 2 and 3). Group 2 (n = 38), initial, and group 3 (n = 33), final and more optimised. All studies were performed in the same 64-MDCT equipment. Cranial deformity protocol was gradationally optimised decreasing kVp, limiting mA range, using automatic exposure control (AEC) and increasing the noise index (NI). Image quality was assessed. Dose indicators such us CT dose index volume (CTDIvol), dose-length product (DLP) and effective dose (E) were used. The optimised low-dose protocol reached the following values: 80 kVp, mA range: 50-150 and NI = 23. We achieved a maximum dose reduction of 10-22 times in the 1- to 12-month-old cranium in regard to the 2004 European guidelines for MDCT. A low-dose MDCT protocol that may be used as the first diagnostic imaging option in clinically selected patients with skull abnormalities. (orig.)

  11. The bibliometric analysis of literatures on low-dose CT in CNKI

    International Nuclear Information System (INIS)

    Wang Qian; Qi Weiwei; Xia Guanghui; Zhao Xinming; Ma Xiaohong; Zhou Chunwu; Hong Nan

    2013-01-01

    Objective: The purposes of this study were to evaluate the characteristics and rule of the development in national low -dose CT examination, and to supply a useful reference for future studies. Materials and Methods: The journal articles in CNKI which were included by China Academic Journal Network Publishing Database (CAJD) from 2002 to 2011 were processed with Thomson Data Analyzer (TDA). Seven aspects were analyzed: time, authors, funds for scientific research, areal distribution, institutions, authors, and keywords. Results: A total 3148 journal articles on low-dose CT examination and 7352 authors were found. The cooperative rate and degree were 63, 48% and 2.34, respectively. The famous authors were those who published more than 3 articles. Authors were from 33 areas, 471 institutions of 8 systems. Beijing and Shanghai were the most productive areas, publishing 45.9% articles. There were 10 core journals in this research area, 868 articles were funded by certain grants, and number of articles was increased yearly, indicative of the importance of grant in promoting research. Conclusion: The national low-dose CT research was in the young stage compared to the international research, and the research were not evenly distributed national wide. Though the researches have involved multi-institute, multi-system, multi-discipline, the quantities and qualities of papers still have improvement space. Strengthening basic research, improving medical ethics, and optimizing clinical research methods would promote development of low-dose CT studies. (authors)

  12. Convolutional auto-encoder for image denoising of ultra-low-dose CT

    Directory of Open Access Journals (Sweden)

    Mizuho Nishio

    2017-08-01

    Conclusion: Neural network with convolutional auto-encoder could be trained using pairs of standard-dose and ultra-low-dose CT image patches. According to the visual assessment by radiologists and technologists, the performance of our proposed method was superior to that of large-scale nonlocal mean and block-matching and 3D filtering.

  13. Low dose intravesical heparin as prophylaxis against recurrent noninvasive (stage Ta) bladder cancer

    DEFF Research Database (Denmark)

    Bitsch, M; Hermann, G G; Andersen, J P

    1990-01-01

    A controlled randomized clinical trial was conducted to examine the efficacy of topical low dose heparin (0.125 gm./l., 25,000 units per l.) as prophylaxis against recurrent noninvasive (stage Ta) transitional cell bladder cancer. Transurethral tumor resection was done with irrigation fluid conta...

  14. The new in molecular mechanisms of the action of the irradiation in low doses

    International Nuclear Information System (INIS)

    Pukhteeva, I.V.; Gerasimovich, N.V.; Prokopenko, N.V.

    2011-01-01

    The data about nontarged effect after ionizing irradiation in low doses are considered. It is noted that activate or inhibit the synthesis of protein factor leading to cell cycle arrest in the checkpoints, to apoptosis in intact cells. Potential prospective research directions in radiobiology in connection with the data of bystander effect, adaptive protection are reviewed.

  15. Characterization of MOSFET dosimeters for low-dose measurements in maxillofacial anthropomorphic phantoms

    NARCIS (Netherlands)

    Koivisto, J.H.; Wolff, J.E.; Kiljunen, T.; Schulze, D.; Kortesniemi, M.

    2015-01-01

    The aims of this study were to characterize reinforced metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters to assess the measurement uncertainty, single exposure low-dose limit with acceptable accuracy, and the number of exposures required to attain the corresponding limit of the

  16. Low-dose N-butyldeoxynojirimycin (OGT 918) for type I Gaucher disease

    NARCIS (Netherlands)

    Heitner, Rene; Elstein, Deborah; Aerts, Johannes; Weely, Sonja van; Zimran, Ari

    2002-01-01

    The objective of this study was to evaluate the efficacy and safety of low-dose substrate balance therapy with OGT 918 for the treatment of adults with Gaucher disease. Eighteen patients with Gaucher disease from two centers were enrolled in an open-label 6-month study of OGT 918, 50 mg taken three

  17. Measurement bias dependence of enhanced bipolar gain degradation at low dose rates

    International Nuclear Information System (INIS)

    Witczak, S.C.; Lacoe, R.C.; Mayer, D.C.; Fleetwood, D.M.

    1998-03-01

    Oxide trapped charge, field effects from emitter metallization, and high level injection phenomena moderate enhanced gain degradation of lateral pnp transistors at low dose rates. Hardness assurance tests at elevated irradiation temperatures require larger design margins for low power measurement biases

  18. Use of a monophasic, low dose oral contraceptive in relation to mental functioning

    NARCIS (Netherlands)

    Deijen, J.B.; Jansen, W.A.; Klitsie, J.; Duyn, K.

    1992-01-01

    The objective of the study was to evaluate the effect of Minulet, a new low-dose oral contraceptive on mood in two groups and to compare the effect with a control group of women not taking oral contraceptives (OC). The women participating were between 16 and 45 years of age. They completed the

  19. Synergistic cancer growth-inhibitory effect of emodin and low-dose ...

    African Journals Online (AJOL)

    Purpose: To investigate the anti-cancer activity of emodin and its combination with low-dose cisplatin against human gastric cancer (SNU-5), including their effects on cell cycle phase distribution, apoptosis and cancer cell morphology. Methods: The anti-cancer activity of emodin, cisplatin and their combination against ...

  20. Comparison of the uncertainties of several European low-dose calibration facilities

    Science.gov (United States)

    Dombrowski, H.; Cornejo Díaz, N. A.; Toni, M. P.; Mihelic, M.; Röttger, A.

    2018-04-01

    The typical uncertainty of a low-dose rate calibration of a detector, which is calibrated in a dedicated secondary national calibration laboratory, is investigated, including measurements in the photon field of metrology institutes. Calibrations at low ambient dose equivalent rates (at the level of the natural ambient radiation) are needed when environmental radiation monitors are to be characterised. The uncertainties of calibration measurements in conventional irradiation facilities above ground are compared with those obtained in a low-dose rate irradiation facility located deep underground. Four laboratories quantitatively evaluated the uncertainties of their calibration facilities, in particular for calibrations at low dose rates (250 nSv/h and 1 μSv/h). For the first time, typical uncertainties of European calibration facilities are documented in a comparison and the main sources of uncertainty are revealed. All sources of uncertainties are analysed, including the irradiation geometry, scattering, deviations of real spectra from standardised spectra, etc. As a fundamental metrological consequence, no instrument calibrated in such a facility can have a lower total uncertainty in subsequent measurements. For the first time, the need to perform calibrations at very low dose rates (< 100 nSv/h) deep underground is underpinned on the basis of quantitative data.

  1. Mutational influences of low-dose and high let ionizing radiation in drosophila melanogaster

    Science.gov (United States)

    Lei, Huang; Fanjun, Kong; Sun, Yeqing

    For cosmic environment consists of a varying kinds of radiation particles including high Z and energy ions which was charactered with low-dose and high RBE, it is important to determine the possible biofuctions of high LET radiation on human beings. To analyse the possible effectes of mutational influences of low-dose and high-LET ionizing radiation, wild fruit flies drosophila melanogaster were irradiated by 12C6+ ions in two LET levels (63.3 and 30 keV/µum) with different low doses from 2mGy to 2000mGy (2, 20, 200, 2000mGy) in HIRFL (Heavy ion radiation facility laboratory, lanzhou, China).In the same LET value group, the average polymorphic frequency was elevated along with adding doses of irradation, the frequency in 2000 mGy dose samples was significantly higher than other samples (p<0.01).These results suggest that genomic DNA sequence could be effected by low-dose and high-LET ionizing radiation, the irradiation dose is an important element in genomic mutation frequency origination.

  2. Cancer risk at low doses of ionizing radiation. Artificial neural networks inference from atomic bomb survivors

    International Nuclear Information System (INIS)

    Sasaki, Masao S.; Tachibana, Akira; Takeda, Shunichi

    2014-01-01

    Cancer risk at low doses of ionizing radiation remains poorly defined because of ambiguity in the quantitative link to doses below 0.2 Sv in atomic bomb survivors in Hiroshima and Nagasaki arising from limitations in the statistical power and information available on overall radiation dose. To deal with these difficulties, a novel nonparametric statistics based on the ‘integrate-and-fire’ algorithm of artificial neural networks was developed and tested in cancer databases established by the Radiation Effects Research Foundation. The analysis revealed unique features at low doses that could not be accounted for by nominal exposure dose, including (1) the presence of a threshold that varied with organ, gender and age at exposure, and (2) a small but significant bumping increase in cancer risk at low doses in Nagasaki that probably reflects internal exposure to 239 Pu. The threshold was distinct from the canonical definition of zero effect in that it was manifested as negative excess relative risk, or suppression of background cancer rates. Such a unique tissue response at low doses of radiation exposure has been implicated in the context of the molecular basis of radiation–environment interplay in favor of recently emerging experimental evidence on DNA double-strand break repair pathway choice and its epigenetic memory by histone marking. (author)

  3. More than lung cancer: Automated analysis of low-dose screening CT scans

    NARCIS (Netherlands)

    Mets, O.M.

    2012-01-01

    Smoking is a major health care problem and is projected to cause over 8 million deaths per year worldwide in the coming decades. To reduce lung cancer mortality in heavy smokers, several randomized screening trials were initiated in the past years using screening with low-dose Computed Tomography

  4. Effect of Low Dose Lead (Pb) Administration on Tail Immersion Test ...

    African Journals Online (AJOL)

    olayemitoyin

    Effect of Low Dose Lead (Pb) Administration on Tail ... Acute and sub-acute effects of lead are caused by relatively large ... As such, the brain is the organ most studied in lead toxicity. ..... inflammatory Properties of Hydro-alcohol Extract of.

  5. LOW-DOSE BROMOCRIPTINE-INDUCED PLEURAL EFFUSION AND PLEUROPULMONARY FIBROSIS

    NARCIS (Netherlands)

    BRUNT, ERP; BOEREE, MJ

    We describe a parkinsonian patient who developed a slight asymptomatic pleural effusion during prolonged therapy with low dose bromocriptine (BCR) in addition to levodopa, following prior treatment with CQA 206-291. A moderate increase of BCR dosage prompted a severe pleuropulmonary inflammatory

  6. Changes in Plasma Corticosterone and Catecholamine Contents Induced by Low Doses of Deltamethrin in Rats

    NARCIS (Netherlands)

    Boer, Sietse F. de; Gugten, Jan van der; Slangen, Jef. L.; Hijzen, Theo H.

    1988-01-01

    The effects of low doses of (S)-α-cyano-3-phenoxybenzyl (1R)-cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylate (Roussel UCLAF, Paris, France), (deltamethrin) upon sympathetic-adrenomedullary and pituitary-adrenocortical activity were investigated in rats by measuring plasma noradrenaline

  7. Decline of HIV antigen levels in cerebrospinal fluid during treatment with low-dose zidovudine

    NARCIS (Netherlands)

    de Gans, J.; Lange, J. M.; Derix, M. M.; de Wolf, F.; Eeftinck Schattenkerk, J. K.; Danner, S. A.; Ongerboer de Visser, B. W.; Cload, P.; Goudsmit, J.

    1988-01-01

    Six HIV-antigenaemic patients with AIDS or AIDS-related complex were studied to assess the effect of treatment with low-dose zidovudine (250 mg) in 6-hourly doses on HIV antigen (HIV-Ag) levels in cerebrospinal fluid (CSF). HIV-Ag was detected in CSF of three patients before treatment. These

  8. Effects of a preovulatory single low dose of mifepristone on ovarian function

    NARCIS (Netherlands)

    van der Stege, Jolande G.; Pahl-van Beest, Elske H.; Beerthuizen, Rob J. C. M.; van Lunsen, Rik H. W.; Scholten, Piet C.; Bogchelman, Dick H.

    Objectives To investigate the effect of a single low dose of mifepristone on ovarian function, when administered in the preovulatory period. Methods Healthy women with regular menstrual cycles were studied during two consecutive menstrual cycles. Either mifepristone or placebo was given in a

  9. Effects of Chronic Low-Dose Radiation on Human Neural Progenitor Cells

    Science.gov (United States)

    Katsura, Mari; Cyou-Nakamine, Hiromasa; Zen, Qin; Zen, Yang; Nansai, Hiroko; Amagasa, Shota; Kanki, Yasuharu; Inoue, Tsuyoshi; Kaneki, Kiyomi; Taguchi, Akashi; Kobayashi, Mika; Kaji, Toshiyuki; Kodama, Tatsuhiko; Miyagawa, Kiyoshi; Wada, Youichiro; Akimitsu, Nobuyoshi; Sone, Hideko

    2016-01-01

    The effects of chronic low-dose radiation on human health have not been well established. Recent studies have revealed that neural progenitor cells are present not only in the fetal brain but also in the adult brain. Since immature cells are generally more radiosensitive, here we investigated the effects of chronic low-dose radiation on cultured human neural progenitor cells (hNPCs) derived from embryonic stem cells. Radiation at low doses of 31, 124 and 496 mGy per 72 h was administered to hNPCs. The effects were estimated by gene expression profiling with microarray analysis as well as morphological analysis. Gene expression was dose-dependently changed by radiation. By thirty-one mGy of radiation, inflammatory pathways involving interferon signaling and cell junctions were altered. DNA repair and cell adhesion molecules were affected by 124 mGy of radiation while DNA synthesis, apoptosis, metabolism, and neural differentiation were all affected by 496 mGy of radiation. These in vitro results suggest that 496 mGy radiation affects the development of neuronal progenitor cells while altered gene expression was observed at a radiation dose lower than 100 mGy. This study would contribute to the elucidation of the clinical and subclinical phenotypes of impaired neuronal development induced by chronic low-dose radiation.

  10. Low-Dose Adefovir-Induced Hypophosphatemic Osteomalacia on Whole-Body Bone Scintigraphy

    International Nuclear Information System (INIS)

    Kim, Sung Hoon; Won, Kyoung Sook; Song, Bongil; Jo, Il; Zeon, Seok Kil

    2013-01-01

    While adefovir dipivoxil (ADV) effectively suppresses the hepatitis B virus, it can cause proximal renal tubular dysfunction leading to phosphate wasting. The safety of low-dose ADV (a dose of 10 mg/day), which does not induce clinically significant nephrotoxicity, is well recognized, but a few cases of hypophosphatemic osteomalacia (HO) caused by low-dose ADV therapy have recently been reported. Although HO induced by low-dose ADV therapy is rare, the presence of bone pain in patients treated with ADV should be monitored. Bone scintigraphy can be performed to confirm the occurrence of osteomalacia and to determine the disease extent. Bone scintigraphic and radiological image findings with a brief review of the literature are presented in this article. We report two cases of HO induced by low-dose ADV therapy that showed multifocal increased radiotracer uptakes in the bilateral bony ribs, spines, pelvic bones and lower extremities on whole-body bone scintigraphy. Bone pain gradually improved after phosphate supplementation and by changing the antiviral agent. Whole-body bone scintigraphy is a highly sensitive imaging tool and can show disease extent at once in the setting of the wide range of the clinical spectrum with nonspecific radiological findings. Furthermore, frequent involvement of the lower extremities, as a result of maximum weight bearing, could be an additional scintigraphic clue for the diagnosis of HO. These cases could be helpful for both clinicians prescribing ADV and nuclear physicians to prevent delayed diagnosis and plan further appropriate treatment

  11. Intraoperative use of low-dose recombinant activated factor VII during thoracic aortic operations.

    Science.gov (United States)

    Andersen, Nicholas D; Bhattacharya, Syamal D; Williams, Judson B; Fosbol, Emil L; Lockhart, Evelyn L; Patel, Mayur B; Gaca, Jeffrey G; Welsby, Ian J; Hughes, G Chad

    2012-06-01

    Numerous studies have supported the effectiveness of recombinant activated factor VII (rFVIIa) for the control of bleeding after cardiac procedures; however safety concerns persist. Here we report the novel use of intraoperative low-dose rFVIIa in thoracic aortic operations, a strategy intended to improve safety by minimizing rFVIIa exposure. Between July 2005 and December 2010, 425 consecutive patients at a single referral center underwent thoracic aortic operations with cardiopulmonary bypass (CPB); 77 of these patients received intraoperative low-dose rFVIIa (≤60 μg/kg) for severe coagulopathy after CPB. Propensity matching produced a cohort of 88 patients (44 received intraoperative low-dose rFVIIa and 44 controls) for comparison. Matched patients receiving intraoperative low-dose rFVIIa got an initial median dose of 32 μg/kg (interquartile range [IQR], 16-43 μg/kg) rFVIIa given 51 minutes (42-67 minutes) after separation from CPB. Patients receiving intraoperative low-dose rFVIIa demonstrated improved postoperative coagulation measurements (partial thromboplastin time 28.6 versus 31.5 seconds; p=0.05; international normalized ratio, 0.8 versus 1.2; pproduct transfusions (2.5 versus 5.0 units; p=0.05) compared with control patients. No patient receiving intraoperative low-dose rFVIIa required postoperative rFVIIa administration or reexploration for bleeding. Rates of stroke, thromboembolism, myocardial infarction, and other adverse events were equivalent between groups. Intraoperative low-dose rFVIIa led to improved postoperative hemostasis with no apparent increase in adverse events. Intraoperative rFVIIa administration in appropriately selected patients may correct coagulopathy early in the course of refractory blood loss and lead to improved safety through the use of smaller rFVIIa doses. Appropriately powered randomized studies are necessary to confirm the safety and efficacy of this approach. Copyright © 2012 The Society of Thoracic Surgeons

  12. The biological effect of 125I seed continuous low dose rate irradiation in CL187 cells

    Directory of Open Access Journals (Sweden)

    Zhuang Hong-Qing

    2009-01-01

    Full Text Available Abstract Background To investigate the effectiveness and mechanism of 125I seed continuous low-dose-rate irradiation on colonic cell line CL187 in vitro. Methods The CL187 cell line was exposed to radiation of 60Coγ ray at high dose rate of 2 Gy/min and 125I seed at low dose rate of 2.77 cGy/h. Radiation responses to different doses and dose rates were evaluated by colony-forming assay. Under 125I seed low dose rate irradiation, a total of 12 culture dishes were randomly divided into 4 groups: Control group, and 2, 5, and 10 Gy irradiation groups. At 48 h after irradiation, apoptosis was detected by Annexin and Propidium iodide (PI staining. Cell cycle arrests were detected by PI staining. In order to investigate the influence of low dose rate irradiation on the MAPK signal transduction, the expression changes of epidermal growth factor receptor (EGFR and Raf under continuous low dose rate irradiation (CLDR and/or EGFR monoclonal antibodies were determined by indirect immunofluorescence. Results The relative biological effect (RBE for 125I seeds compared with 60Co γ ray was 1.41. Apoptosis rates of CL187 cancer cells were 13.74% ± 1.63%, 32.58% ± 3.61%, and 46.27% ± 3.82% after 2 Gy, 5 Gy, and 10 Gy irradiation, respectively; however, the control group apoptosis rate was 1.67% ± 0.19%. G2/M cell cycle arrests of CL187 cancer cells were 42.59% ± 3.21%, 59.84% ± 4.96%, and 34.61% ± 2.79% after 2 Gy, 5 Gy, and 10 Gy irradiation, respectively; however, the control group apoptosis rate was 26.44% ± 2.53%. P 2/M cell cycle arrest. After low dose rate irradiation, EGFR and Raf expression increased, but when EGFR was blocked by a monoclonal antibody, EGFR and Raf expression did not change. Conclusion 125I seeds resulted in more effective inhibition than 60Co γ ray high dose rate irradiation in CL187 cells. Apoptosis following G2/M cell cycle arrest was the main mechanism of cell-killing effects under low dose rate irradiation. CLDR could

  13. Low-dose-rate total lymphoid irradiation: a new method of rapid immunosuppression

    International Nuclear Information System (INIS)

    Blum, J.E.; de Silva, S.M.; Rachman, D.B.; Order, S.E.

    1988-01-01

    Total Lymphoid Irradiation (TLI) has been successful in inducing immunosuppression in experimental and clinical applications. However, both the experimental and clinical utility of TLI are hampered by the prolonged treatment courses required (23 days in rats and 30-60 days in humans). Low-dose-rate TLI has the potential of reducing overall treatment time while achieving comparable immunosuppression. This study examines the immunosuppressive activity and treatment toxicity of conventional-dose-rate (23 days) vs low-dose-rate (2-7 days) TLI. Seven groups of Lewis rats were given TLI with 60Co. One group was treated at conventional-dose-rates (80-110 cGy/min) and received 3400 cGy in 17 fractions over 23 days. Six groups were treated at low-dose-rate (7 cGy/min) and received total doses of 800, 1200, 1800, 2400, 3000, and 3400 cGy over 2-7 days. Rats treated at conventional-dose-rates over 23 days and at low-dose-rate over 2-7 days tolerated radiation with minimal toxicity. The level of immunosuppression was tested using allogeneic (Brown-Norway) skin graft survival. Control animals retained allogeneic skin grafts for a mean of 14 days (range 8-21 days). Conventional-dose-rate treated animals (3400 cGy in 23 days) kept their grafts 60 days (range 50-66 days) (p less than .001). Low-dose-rate treated rats (800 to 3400 cGy total dose over 2-7 days) also had prolongation of allogeneic graft survival times following TLI with a dose-response curve established. The graft survival time for the 3400 cGy low-dose-rate group (66 days, range 52-78 days) was not significantly different from the 3400 cGy conventional-dose-rate group (p less than 0.10). When the total dose given was equivalent, low-dose-rate TLI demonstrated an advantage of reduced overall treatment time compared to conventional-dose-rate TLI (7 days vs. 23 days) with no increase in toxicity

  14. Low dose dynamic CT myocardial perfusion imaging using a statistical iterative reconstruction method

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Yinghua [Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53705 (United States); Chen, Guang-Hong [Department of Medical Physics and Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin 53705 (United States); Hacker, Timothy A.; Raval, Amish N. [Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin 53792 (United States); Van Lysel, Michael S.; Speidel, Michael A., E-mail: speidel@wisc.edu [Department of Medical Physics and Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin 53705 (United States)

    2014-07-15

    Purpose: Dynamic CT myocardial perfusion imaging has the potential to provide both functional and anatomical information regarding coronary artery stenosis. However, radiation dose can be potentially high due to repeated scanning of the same region. The purpose of this study is to investigate the use of statistical iterative reconstruction to improve parametric maps of myocardial perfusion derived from a low tube current dynamic CT acquisition. Methods: Four pigs underwent high (500 mA) and low (25 mA) dose dynamic CT myocardial perfusion scans with and without coronary occlusion. To delineate the affected myocardial territory, an N-13 ammonia PET perfusion scan was performed for each animal in each occlusion state. Filtered backprojection (FBP) reconstruction was first applied to all CT data sets. Then, a statistical iterative reconstruction (SIR) method was applied to data sets acquired at low dose. Image voxel noise was matched between the low dose SIR and high dose FBP reconstructions. CT perfusion maps were compared among the low dose FBP, low dose SIR and high dose FBP reconstructions. Numerical simulations of a dynamic CT scan at high and low dose (20:1 ratio) were performed to quantitatively evaluate SIR and FBP performance in terms of flow map accuracy, precision, dose efficiency, and spatial resolution. Results: Forin vivo studies, the 500 mA FBP maps gave −88.4%, −96.0%, −76.7%, and −65.8% flow change in the occluded anterior region compared to the open-coronary scans (four animals). The percent changes in the 25 mA SIR maps were in good agreement, measuring −94.7%, −81.6%, −84.0%, and −72.2%. The 25 mA FBP maps gave unreliable flow measurements due to streaks caused by photon starvation (percent changes of +137.4%, +71.0%, −11.8%, and −3.5%). Agreement between 25 mA SIR and 500 mA FBP global flow was −9.7%, 8.8%, −3.1%, and 26.4%. The average variability of flow measurements in a nonoccluded region was 16.3%, 24.1%, and 937

  15. Low dose dynamic CT myocardial perfusion imaging using a statistical iterative reconstruction method

    International Nuclear Information System (INIS)

    Tao, Yinghua; Chen, Guang-Hong; Hacker, Timothy A.; Raval, Amish N.; Van Lysel, Michael S.; Speidel, Michael A.

    2014-01-01

    Purpose: Dynamic CT myocardial perfusion imaging has the potential to provide both functional and anatomical information regarding coronary artery stenosis. However, radiation dose can be potentially high due to repeated scanning of the same region. The purpose of this study is to investigate the use of statistical iterative reconstruction to improve parametric maps of myocardial perfusion derived from a low tube current dynamic CT acquisition. Methods: Four pigs underwent high (500 mA) and low (25 mA) dose dynamic CT myocardial perfusion scans with and without coronary occlusion. To delineate the affected myocardial territory, an N-13 ammonia PET perfusion scan was performed for each animal in each occlusion state. Filtered backprojection (FBP) reconstruction was first applied to all CT data sets. Then, a statistical iterative reconstruction (SIR) method was applied to data sets acquired at low dose. Image voxel noise was matched between the low dose SIR and high dose FBP reconstructions. CT perfusion maps were compared among the low dose FBP, low dose SIR and high dose FBP reconstructions. Numerical simulations of a dynamic CT scan at high and low dose (20:1 ratio) were performed to quantitatively evaluate SIR and FBP performance in terms of flow map accuracy, precision, dose efficiency, and spatial resolution. Results: Forin vivo studies, the 500 mA FBP maps gave −88.4%, −96.0%, −76.7%, and −65.8% flow change in the occluded anterior region compared to the open-coronary scans (four animals). The percent changes in the 25 mA SIR maps were in good agreement, measuring −94.7%, −81.6%, −84.0%, and −72.2%. The 25 mA FBP maps gave unreliable flow measurements due to streaks caused by photon starvation (percent changes of +137.4%, +71.0%, −11.8%, and −3.5%). Agreement between 25 mA SIR and 500 mA FBP global flow was −9.7%, 8.8%, −3.1%, and 26.4%. The average variability of flow measurements in a nonoccluded region was 16.3%, 24.1%, and 937

  16. Low-dose radiation employed in diagnostic imaging causes genetic effects in cultured cells

    International Nuclear Information System (INIS)

    Ponzinibbio, Maria V.; Peral-Garcia, Pilar; Seoane, Analia; Crudeli, Cintia

    2010-01-01

    Background: Exposure to environmental, diagnostic, and occupational sources of radiation frequently involves low doses. Although these doses have no immediately noticeable impact on human health there is great interest in their long-term biological effects. Purpose: To assess immediate and time-delayed DNA damage in two cell lines exposed to low doses of ionizing radiation by using the comet assay and micronucleus test, and to compare these two techniques in the analysis of low-dose induced genotoxicity. Material and Methods: CHO and MRC-5 cells were exposed to 50 milliSievert (mSv) of ionizing radiation and assayed immediately after irradiation and at 16 or 12 passages post-irradiation, respectively. Comet assay and micronucleus test were employed. Results: The comet assay values observed in 50 mSv-treated cells were significantly higher than in the control group for both sample times and cell lines (P < 0.001). Micronuclei frequencies were higher in treated cells than in the control group (P < 0.01, CHO cells passage 16; P < 0.05, MRC-5 cells immediately after exposure; P < 0.01 MRC-5 cells passage 12). Correlation analysis between the two techniques was statistically significant (correlation coefficient 0.82, P < 0.05 and correlation coefficient 0.86, P < 0.05 for CHO and MRC-5 cells, respectively). Cells scored at passages 12 or 16 showed more damage than those scored immediately after exposure in both cell lines (no statistically significant differences). Conclusion: Cytomolecular and cytogenetic damage was observed in cells exposed to very low doses of X-rays and their progeny. A single low dose of ionizing radiation was sufficient to induce such response, indicating that mammalian cells are exquisitely sensitive to it. Comet and micronucleus assays are sensitive enough to assess this damage, although the former seems to be more efficient

  17. Detection of lung nodules with low-dose spiral CT: comparison with conventional dose CT

    International Nuclear Information System (INIS)

    Zhu Tianzhao; Tang Guangjian; Jiang Xuexiang

    2004-01-01

    Objective: To investigate the effect of reducing scan dose on the lung nodules detection rate by scanning a lung nodule model at low dose and conventional dose. Methods: The lung and the thoracic cage were simulated by using a cyst filled with water surrounded by a roll bandage. Flour, butter, and paraffin wax were mixed together by a certain ratio to simulate lung nodules of 10 mm and 5 mm in diameter with the CT values ranging from -10 to 50 HU. Conventional-dose scan (240 mA, 140 kV) and low-dose scan of three different levels (43 mA, 140 kV; 50 mA, 120 kV; 75 mA, 80 kV) together with three different pitches (1.0, 1.5, and 2.0) were performed. The images of the simulated nodules were combined with the CT images of a normal adult's upper, middle, and inferior lung. Three radiologists read the images and the number of the nodules they detected including both the real ones and the false-positive ones was calculated to investigate weather there was any difference among different doses, pitch groups, and different locations. Results: The detection rate of the 10 mm and 5 mm nodules was 100% and 89.6% respectively by the low-dose scan. There was no difference between low-dose and conventional-dose CT (χ 2 =0.6907, P>0.70). The detection rate of 5 mm nodules declined when large pitch was used. Conclusion: The detection rates of 10 mm and 5 mm nodules had no difference between low-dose CT and conventional-dose CT. As the pitch augmented, the detection rate for the nodules declined

  18. Generative Adversarial Networks for Noise Reduction in Low-Dose CT.

    Science.gov (United States)

    Wolterink, Jelmer M; Leiner, Tim; Viergever, Max A; Isgum, Ivana

    2017-12-01

    Noise is inherent to low-dose CT acquisition. We propose to train a convolutional neural network (CNN) jointly with an adversarial CNN to estimate routine-dose CT images from low-dose CT images and hence reduce noise. A generator CNN was trained to transform low-dose CT images into routine-dose CT images using voxelwise loss minimization. An adversarial discriminator CNN was simultaneously trained to distinguish the output of the generator from routine-dose CT images. The performance of this discriminator was used as an adversarial loss for the generator. Experiments were performed using CT images of an anthropomorphic phantom containing calcium inserts, as well as patient non-contrast-enhanced cardiac CT images. The phantom and patients were scanned at 20% and 100% routine clinical dose. Three training strategies were compared: the first used only voxelwise loss, the second combined voxelwise loss and adversarial loss, and the third used only adversarial loss. The results showed that training with only voxelwise loss resulted in the highest peak signal-to-noise ratio with respect to reference routine-dose images. However, CNNs trained with adversarial loss captured image statistics of routine-dose images better. Noise reduction improved quantification of low-density calcified inserts in phantom CT images and allowed coronary calcium scoring in low-dose patient CT images with high noise levels. Testing took less than 10 s per CT volume. CNN-based low-dose CT noise reduction in the image domain is feasible. Training with an adversarial network improves the CNNs ability to generate images with an appearance similar to that of reference routine-dose CT images.

  19. Exposure of luminous marine bacteria to low-dose gamma-radiation.

    Science.gov (United States)

    Kudryasheva, N S; Petrova, A S; Dementyev, D V; Bondar, A A

    2017-04-01

    The study addresses biological effects of low-dose gamma-radiation. Radioactive 137 Cs-containing particles were used as model sources of gamma-radiation. Luminous marine bacterium Photobacterium phosphoreum was used as a bioassay with the bioluminescent intensity as the physiological parameter tested. To investigate the sensitivity of the bacteria to the low-dose gamma-radiation exposure (≤250 mGy), the irradiation conditions were varied as follows: bioluminescence intensity was measured at 5, 10, and 20°С for 175, 100, and 47 h, respectively, at different dose rates (up to 4100 μGy/h). There was no noticeable effect of gamma-radiation at 5 and 10°С, while the 20°С exposure revealed authentic bioluminescence inhibition. The 20°С results of gamma-radiation exposure were compared to those for low-dose alpha- and beta-radiation exposures studied previously under comparable experimental conditions. In contrast to ionizing radiation of alpha and beta types, gamma-emission did not initiate bacterial bioluminescence activation (adaptive response). As with alpha- and beta-radiation, gamma-emission did not demonstrate monotonic dose-effect dependencies; the bioluminescence inhibition efficiency was found to be related to the exposure time, while no dose rate dependence was found. The sequence analysis of 16S ribosomal RNA gene did not reveal a mutagenic effect of low-dose gamma radiation. The exposure time that caused 50% bioluminescence inhibition was suggested as a test parameter for radiotoxicity evaluation under conditions of chronic low-dose gamma irradiation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Low-Dose Radiation Therapy (2 Gy × 2) in the Treatment of Orbital Lymphoma

    Energy Technology Data Exchange (ETDEWEB)

    Fasola, Carolina E. [Department of Radiation Oncology, Stanford University, Stanford, California (United States); Jones, Jennifer C. [Vaccine Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland (United States); Huang, Derek D. [Department of Internal Medicine, University of California-Los Angeles Olive View, Sylmar, California (United States); Le, Quynh-Thu; Hoppe, Richard T. [Department of Radiation Oncology, Stanford University, Stanford, California (United States); Donaldson, Sarah S., E-mail: sarah2@stanford.edu [Department of Radiation Oncology, Stanford University, Stanford, California (United States)

    2013-08-01

    Purpose: Low-dose radiation has become increasingly used in the management of indolent non-Hodgkin lymphoma (NHL), but has not been studied specifically for cases of ocular adnexal involvement. The objective of this study is to investigate the effectiveness of low-dose radiation in the treatment of NHL of the ocular adnexa. Methods and Materials: We reviewed the records of 20 NHL patients with 27 sites of ocular adnexal involvement treated with low-dose radiation consisting of 2 successive fractions of 2 Gy at our institution between 2005 and 2011. The primary endpoint of this study is freedom from local relapse (FFLR). Results: At a median follow-up time of 26 months (range 7-92), the overall response rate for the 27 treated sites was 96%, with a complete response (CR) rate of 85% (n=23) and a partial response rate of 11% (n=3). Among all treated sites with CR, the 2-year FFLR was 100%, with no in-treatment field relapses. The 2-year freedom from regional relapse rate was 96% with 1 case of relapse within the ipsilateral orbit (outside of the treatment field). This patient underwent additional treatment with low-dose radiation of 4 Gy to the area of relapse achieving a CR and no evidence of disease at an additional 42 months of follow-up. Orbital radiation was well tolerated with only mild acute side effects (dry eye, conjunctivitis, transient periorbital edema) in 30% of treated sites without any reports of long-term toxicity. Conclusions: Low-dose radiation with 2 Gy × 2 is effective and well tolerated in the treatment of indolent NHL of the ocular adnexa with high response rates and durable local control with the option of reirradiation in the case of locoregional relapse.

  1. Low-Dose Radiation Therapy (2 Gy × 2) in the Treatment of Orbital Lymphoma

    International Nuclear Information System (INIS)

    Fasola, Carolina E.; Jones, Jennifer C.; Huang, Derek D.; Le, Quynh-Thu; Hoppe, Richard T.; Donaldson, Sarah S.

    2013-01-01

    Purpose: Low-dose radiation has become increasingly used in the management of indolent non-Hodgkin lymphoma (NHL), but has not been studied specifically for cases of ocular adnexal involvement. The objective of this study is to investigate the effectiveness of low-dose radiation in the treatment of NHL of the ocular adnexa. Methods and Materials: We reviewed the records of 20 NHL patients with 27 sites of ocular adnexal involvement treated with low-dose radiation consisting of 2 successive fractions of 2 Gy at our institution between 2005 and 2011. The primary endpoint of this study is freedom from local relapse (FFLR). Results: At a median follow-up time of 26 months (range 7-92), the overall response rate for the 27 treated sites was 96%, with a complete response (CR) rate of 85% (n=23) and a partial response rate of 11% (n=3). Among all treated sites with CR, the 2-year FFLR was 100%, with no in-treatment field relapses. The 2-year freedom from regional relapse rate was 96% with 1 case of relapse within the ipsilateral orbit (outside of the treatment field). This patient underwent additional treatment with low-dose radiation of 4 Gy to the area of relapse achieving a CR and no evidence of disease at an additional 42 months of follow-up. Orbital radiation was well tolerated with only mild acute side effects (dry eye, conjunctivitis, transient periorbital edema) in 30% of treated sites without any reports of long-term toxicity. Conclusions: Low-dose radiation with 2 Gy × 2 is effective and well tolerated in the treatment of indolent NHL of the ocular adnexa with high response rates and durable local control with the option of reirradiation in the case of locoregional relapse

  2. Comparision the value of detecting myocardial viability between low dose dobutamine stress MRI and echocardiography

    International Nuclear Information System (INIS)

    He Yi; Zhang Zhaoqi; Yu Wei; Miao Cuilian; Zhao Yike; Yan Zixu

    2006-01-01

    Objective: To Compare the diagnostic value between low dose dobutamine stress transthrotic echocardiography and low dose dobutamine stress MRI in detecting myocardial viability of chronic myocardial infarction. Methods: Rest and low dose dobutamine (5, 10 μg·kg -1 ·min -1 ) stress transthrotic echocardiography and cine-MRI were performed in 30 patients with chronic myocardial infarction. 24 patients underwent successful revascularization and 10 of them underwent another rest cine-MRI study to assess segmental myocardial functional recovery. Left ventricular were divided into 16 segments, the criteria of viability in different techniques is: MRI: dobutamine induced systolic wall thickening was ≥2 mm in akinetic or diskinetic segments at rest; Echocardiography: wall motion score reduced at least 1 after dobutamine stress in akinetic or' diskinetic segments at rest. Results: One hundren and eight segments showed wall motion abnormalities of 30 patients, 65 and 56 segments shows positive reaction, 43 and 52 segments shows negativereaction in MRI and echocardiography after dobutamine stress respectively. Kappa value of the two techniques is 0.75, concordance in both techniques is 88%. Twenty-four segments showed functional recovery, 14 segments remained dysfunction 3-6 months after revascularization, the sensitivity, specificity and accuracy of detecting myocardial viability in chronic myocardial infarction in MRI and echocardiography is 95.8% vs 79.2% (P>0.05), 85.7% vs 85.7% (P>0.05), 92.1% vs 81.6% (P>0.05) respectively. The sensitivity and accuracy of MRI is a little higher. Conclusion: The ability of detecting myocardial viability by both low dose dobutamine stress transthrotic echocardiography and low dose dobutamine stress MRI is similer, the sensitivity and accuracy of MRI is a little higher. (authors)

  3. Safety of low-dose aspirin in endovascular treatment for intracranial atherosclerotic stenosis.

    Directory of Open Access Journals (Sweden)

    Ning Ma

    Full Text Available OBJECTIVES: To evaluate the safety of low-dose aspirin plus clopidogrel versus high-dose aspirin plus clopidogrel in prevention of vascular risk within 90 days of duration of dual antiplatelet therapy in patients treated with intracranial endovascular treatment. METHODS: From January 2012 to December 2013, this prospective and observational study enrolled 370 patients with symptomatic intracranial atherosclerotic stenosis of ≥70% with poor collateral undergoing intracranial endovascular treatment. Antiplatelet therapy consists of aspirin, at a low-dose of 100 mg or high-dose of 300 mg daily; clopidogrel, at a dose of 75 mg daily for 5 days before endovascular treatment. The dual antiplatelet therapy continued for 90 days after intervention. The study endpoints include acute thrombosis, subacute thrombosis, stroke or death within 90 days after intervention. RESULTS: Two hundred and seventy three patients received low-dose aspirin plus clopidogrel and 97 patients received high-dose aspirin plus clopidogrel before intracranial endovascular treatment. Within 90 days after intervention, there were 4 patients (1.5% with acute thrombosis, 5 patients (1.8% with subacute thrombosis, 17 patients (6.2% with stroke, and 2 death (0.7% in low-dose aspirin group, compared with no patient (0% with acute thrombosis, 2 patient (2.1% with subacute thrombosis, 6 patients (6.2% with stroke, and 2 death (2.1% in high-dose aspirin group, and there were no significant difference in all study endpoints between two groups. CONCLUSION: Low-dose aspirin plus clopidogrel is comparative in safety with high-dose aspirin plus clopidogrel within 90 days of duration of dual antiplatelet therapy in patients treated with intracranial endovascular treatment.

  4. European Collaboration on Low-dose Aspirin in Polycythemia Vera (ECLAP): a randomized trial.

    Science.gov (United States)

    Landolfi, R; Marchioli, R

    1997-01-01

    Thrombotic complications characterize the clinical course of polycythemia vera (PV) and represent the main cause of morbidity and mortality. However, uncertainty still exists as to the benefit/risk ratio of aspirin prophylaxis in this setting. In vivo platelet biosynthesis of thromboxane A2 is enhanced and can be suppressed by low-dose aspirin in PV, thus providing a rationale for assessing the efficacy and safety of a low-dose aspirin regimen in these patients. The Gruppo Italiano Studio Policitemia Vera has recently performed a pilot study on 112 patients randomized to receive aspirin, 40 mg daily, or placebo and followed for 16 +/- 6 months (mean +/- SD). This study showed that low-dose aspirin is well tolerated in PV patients, and that a large-scale efficacy trial is feasible in this setting. In this article we report the protocol of the European Collaboration on Low-dose Aspirin in Polycythemia Vera (ECLAP) study, which is a randomized trial designed to assess the risk/benefit ratio of low-dose aspirin in PV. To estimate the size and the follow-up duration required for the ECLAP trial, a retrospective analysis of the clinical epidemiology of a large PV population has recently been completed by the Gruppo Italiano Studio Policitemia Vera. On this basis, approximately 3500 patients will be enrolled in the ECLAP study with a follow-up of 3 to 4 years. The uncertainty principle will be used as the main eligibility criterion: Polycythemic patients of any age, having no clear indication for or contraindication to aspirin treatment, will be randomized in a double-blind fashion to receive oral aspirin (100 mg daily) or placebo. According to current therapeutic recommendations, the basic treatment of randomized patients should be aimed at maintaining the hematocrit value 50. Randomization will be stratified by participating center. The study is funded by the European Union BIOMED 2 program.

  5. Low-dose radiation employed in diagnostic imaging causes genetic effects in cultured cells

    Energy Technology Data Exchange (ETDEWEB)

    Ponzinibbio, Maria V.; Peral-Garcia, Pilar; Seoane, Analia (Inst. de Genetica Veterinaria, Univ. Nacional de La Plata CONICET, La Plata (Argentina)), e-mail: aseoane@fcv.unlp.edu.ar; Crudeli, Cintia (Agencia Nacional de Promocion Cientifica y Tecnologica, La Plata (Argentina))

    2010-11-15

    Background: Exposure to environmental, diagnostic, and occupational sources of radiation frequently involves low doses. Although these doses have no immediately noticeable impact on human health there is great interest in their long-term biological effects. Purpose: To assess immediate and time-delayed DNA damage in two cell lines exposed to low doses of ionizing radiation by using the comet assay and micronucleus test, and to compare these two techniques in the analysis of low-dose induced genotoxicity. Material and Methods: CHO and MRC-5 cells were exposed to 50 milliSievert (mSv) of ionizing radiation and assayed immediately after irradiation and at 16 or 12 passages post-irradiation, respectively. Comet assay and micronucleus test were employed. Results: The comet assay values observed in 50 mSv-treated cells were significantly higher than in the control group for both sample times and cell lines (P < 0.001). Micronuclei frequencies were higher in treated cells than in the control group (P < 0.01, CHO cells passage 16; P < 0.05, MRC-5 cells immediately after exposure; P < 0.01 MRC-5 cells passage 12). Correlation analysis between the two techniques was statistically significant (correlation coefficient 0.82, P < 0.05 and correlation coefficient 0.86, P < 0.05 for CHO and MRC-5 cells, respectively). Cells scored at passages 12 or 16 showed more damage than those scored immediately after exposure in both cell lines (no statistically significant differences). Conclusion: Cytomolecular and cytogenetic damage was observed in cells exposed to very low doses of X-rays and their progeny. A single low dose of ionizing radiation was sufficient to induce such response, indicating that mammalian cells are exquisitely sensitive to it. Comet and micronucleus assays are sensitive enough to assess this damage, although the former seems to be more efficient

  6. Toxicity bioassay in mice exposed to low dose-rate radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Joog Sun; Gong, Eun Ji; Heo, Kyu; Yang, Kwang Mo [Research Center, Dongnam Institute of Radiological and Medical Sciences, Busan (Korea, Republic of)

    2013-04-15

    The systemic effect of radiation increases in proportion to the dose amount and rate. The association between accumulated radiation dose and adverse effects, which is derived according to continuous low dose-rate radiation exposure, is not clearly elucidated. Our previous study showed that low dose-rate radiation exposure did not cause adverse effects in BALB/c mice at dose levels of ≤2 Gy, but the testis weight decreased at a dose of 2 Gy. In this study, we studied the effects of irradiation at the low dose rate (3.49 mGy/h) in the testes of C57BL/6 mice. Mice exposed to a total dose of 0.02, 0.2, and 2 Gy were found to be healthy and did not show any significant changes in body weight and peripheral blood components. However, mice irradiated with a dose of 2 Gy had significantly decreased testis weight. Further, histological studies and sperm evaluation also demonstrated changes consistent with the findings of decreased testis weight. In fertile patients found to have arrest of sperm maturation, the seminiferous tubules lack the DNMT1 and HDAC1 protein. The decrease of DNMT1 and HDAC1 in irradiated testis may be the part of the mechanism via which low dose-rate irradiation results in teticular injury. In conclusion, despite a low dose-rate radiation, our study found that when mice testis were irradiated with 2 Gy at 3.49 mGy/h dose rate, there was significant testicular and sperm damage with decreased DNMT1 and HDAC1 expression.

  7. Low Doses of Ethanol Enhance LTD-like Plasticity in Human Motor Cortex.

    Science.gov (United States)

    Fuhl, Anna; Müller-Dahlhaus, Florian; Lücke, Caroline; Toennes, Stefan W; Ziemann, Ulf

    2015-12-01

    Humans liberally use ethanol for its facilitating effects on social interactions but its effects on central nervous system function remain underexplored. We have recently described that very low doses of ethanol abolish long-term potentiation (LTP)-like plasticity in human cortex, most likely through enhancement of tonic inhibition [Lücke et al, 2014, Neuropsychopharmacology 39:1508-18]. Here, we studied the effects of low-dose ethanol on long-term depression (LTD)-like plasticity. LTD-like plasticity was induced in human motor cortex by paired associative transcranial magnetic stimulation (PASLTD), and measured as decreases of motor evoked potential input-output curve (IO-curve). In addition, sedation was measured by decreases in saccade peak velocity (SPV). Ethanol in two low doses (EtOH<10mM, EtOH<20mM) was compared to single oral doses of alprazolam (APZ, 1mg) a classical benzodiazepine, and zolpidem (ZLP, 10 mg), a non-benzodiazepine hypnotic, in a double-blinded randomized placebo-controlled crossover design in ten healthy human subjects. EtOH<10mM and EtOH<20mM but not APZ or ZLP enhanced the PASLTD-induced LTD-like plasticity, while APZ and ZLP but not EtOH<10mM or EtOH<20mM decreased SPV. Non-sedating low doses of ethanol, easily reached during social drinking, enhance LTD-like plasticity in human cortex. This effect is most likely explained by the activation of extrasynaptic α4-subunit containing gamma-aminobutyric type A receptors by low-dose EtOH, resulting in increased tonic inhibition. Findings may stimulate cellular research on the role of tonic inhibition in regulating excitability and plasticity of cortical neuronal networks.

  8. Hormesis of Low Doses of Ionizing Radiation Exposure on Immune System

    International Nuclear Information System (INIS)

    Ragab, M.H.; Abbas, M.O.; El-Asady, R.S.; Amer, H.A.; El-Khouly, W.A.; Shabon, M.H.

    2015-01-01

    The effect of low doses of ionizing radiation on the immune system has been a controversial subject. To evaluate the effect of low-doses γ-irradiation exposure on immune system. An animal model, using Rattus Rattus rats was used. The rats were divided into groups exposed to either continuous or fractionated 100, 200, 300, 400 and 500 mSv of radiation and compared to control rats that did not receive radiation. All groups were exposed to a total white blood count (Wcs), lymphocyte count and serum IgG level measurement, as indicators of the function of the cell-mediated (T lymphocytes) and the humoral (B lymphocytes) immune system. The results of the current study revealed that the counts of total leukocytes (WBCs) and lymphocytes, as well as the serum level of IgG were increased significantly in rats receiving low dose radiation, indicating enhancement of immune system. The data suggests that low-dose gamma-radiation improved hematological parameters and significantly enhances immune response indices of the exposed rats. These findings are similar to the radiation adaptive responses in which a small dose of pre irradiation would induce certain radiation resistance and enhances the cell response after exposure to further irradiation doses The applied low doses used in the present study may appear effective inducing the radio adaptive response. Farooqi and Kesavan (1993) and Bravard et al. (1999) reported that the adaptive response to ionizing radiation refers to the phenomenon by which cells irradiated with low (cGy) or sublethal doses (conditioning doses) become less susceptible to genotoxic effects of a subsequent high dose (challenge dose, several Gy).

  9. MELODI - Multidisciplinary European Low dose Initiative - First Draft of Strategic Research Agenda (SRA)

    International Nuclear Information System (INIS)

    Averbeck, D.; Lloyd, D.; O'Neill, P.

    2010-01-01

    The SRA Working Group of MELODI (Multidisciplinary European Low Dose Initiative) was tasked to develop a long-term strategic research agenda (SRA) to guide the coherent integration of national low dose research programmes. Priorities that need to be addressed concern fundamental mechanistic research ranging from radiation track structure and the deposition of energy in biologically important molecules; the resultant homeostatic perturbations and the steps in the cellular and tissue metabolic pathways that eventually lead to disease pathologies. In fact, the main priorities are here the step-wise elucidation of the mechanisms of radiation-induced (oxidative) stress responses and their impact on radiation-induced cancers and non cancer diseases. To achieve this a holistic approach is proposed staring with radiation-specific effects, radiation-induced molecular, biological and pathological effects involving a systems biology approach as well as molecular epidemiology and mathematical modelling in order to come up with more solid low dose health risk assessments. The pathologies considered are outlined in the report where the need is stressed for the MELODI platform to involve a constellation of classical and emerging technologies in a highly multidisciplinary approach. Elucidating the shapes of low-dose response relationships and resolving the question of thresholds is paramount to resolving questions of risk for both populations and individuals. Much is known about radiation-induced cancer in humans and animal models but this needs to be pursued particularly at low doses. More recently, the scientific community has realised that low radiation-induced health effects range well beyond cancer. The priority non-cancer areas that need to be brought into focus are cardiovascular, neurological and ophthalmic. (A.C.)

  10. Protective Effect of Low Dose Gamma Irradiation against Oxidative Damage in Rats Administrated with Ferric- Nitrilotriacetate

    International Nuclear Information System (INIS)

    Mansonr, S.Z.

    2009-01-01

    Many studies have demonstrated the beneficial adaptive response of low dose gamma-irradiation. Low dose gamma-irradiation (LDR) might be effective for the prevention of various reactive oxygen species-related diseases. Ferric nitrilotriacetate (Fe-NTA) is a strong oxidant, which generates highly reactive hydroxyl radical and causes injuries of various organs including the kidney and liver. This study was designed to investigate the ability of low dose gamma-irradiation to restrain Fe-NT A induced oxidative stress. Sprague Dawley male albino rats were subjected to low dose gamma-irradiation (50 cGy). Animals were challenged with Fe-NT A (9 mg Fe/kg body weight, intraperitoneally). Results showed that Fe-NTA enhances lipid peroxidation (LPx) accompanied with reduction in glutathione (GSH) content, antioxidant enzymes, viz., glutathione peroxidase (GPX), glutathione reductase (GR), superoxide dismutase (SOD), catalase (CAT) and phase-U metabolizing enzyme glutathione-S-transferase (GST). Fe-NTA also enhances the concentration of blood urea nitrogen (BUN) and serum creatinine as well as alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyl transpeptidase (GGT) activities. Exposure to low dose gamma- irradiation (3 h after Fe-NTA administration) resulted in a significant decrease in LPx, BUN, serum creatinine contents as well as ALT, AST and GGT enzyme activities. GSH content; GST and antioxidant enzymes were also recovered to significant level. Thus, our data suggest that exposure to LDR might be a useful antioxidant mediator to suppress the Fe-NTA induced-oxidative damage in rats

  11. Protective Effect of Low Dose Gamma Irradiation against Oxidative Damage in Rats Administrated with Ferric- Nitrilotriacetate

    International Nuclear Information System (INIS)

    Mansonr, S.Z.

    2008-01-01

    Many studies have demonstrated the beneficial adaptive response of low dose gamma-irradiation. Low dose gamma-irradiation (LDR) might be effective for the prevention of various reactive oxygen species-related diseases. Ferric nitrilotriacetate (Fe-NTA) is a strong oxidant, which generates highly reactive hydroxyl radical and causes injuries of various organs including the kidney and liver. This study was designed to investigate the ability of low dose gamma-irradiation to restrain Fe-NT A induced oxidative stress. Sprague Dawley male albino rats were subjected to low dose gamma-irradiation (50 cGy). Animals were challenged with Fe-NT A (9 mg Fe/kg body weight, intraperitoneally). Results showed that Fe-NTA enhances lipid peroxidation (LPx) accompanied with reduction in glutathione (GSH) content, antioxidant enzymes, viz., glutathione peroxidase (GPX), glutathione reductase (GR), superoxide dismutase (SOD), catalase (CAT) and phase-U metabolizing enzyme glutathione-S-transferase (GST). Fe-NTA also enhances the concentration of blood urea nitrogen (BUN) and serum creatinine as well as alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyl transpeptidase (GGT) activities. Exposure to low dose gamma- irradiation (3 h after Fe-NTA administration) resulted in a significant decrease in LPx, BUN, serum creatinine contents as well as ALT, AST and GGT enzyme activities. GSH content; GST and antioxidant enzymes were also recovered to significant level. Thus, our data suggest that exposure to LDR might be a useful antioxidant mediator to suppress the Fe-NTA induced-oxidative damage in rats

  12. AT cells are not radiosensitive for simple chromosomal exchanges at low dose

    International Nuclear Information System (INIS)

    Hada, Megumi; Huff, Janice L.; Patel, Zarana S.; Kawata, Tetsuya; Pluth, Janice M.; George, Kerry A.; Cucinotta, Francis A.

    2011-01-01

    Cells deficient in ATM (product of the gene that is mutated in ataxia telangiectasia patients) or NBS (product of the gene mutated in the Nijmegen breakage syndrome) show increased yields of both simple and complex chromosomal aberrations after high doses (>0.5 Gy) of ionizing radiation (X-rays or γ-rays), however less is known on how these cells respond at low dose. Previously we had shown that the increased chromosome aberrations in ATM and NBS defective lines was due to a significantly larger quadratic dose-response term compared to normal fibroblasts for both simple and complex exchanges. The linear dose-response term for simple exchanges was significantly higher in NBS cells compared to wild type cells, but not for AT cells. However, AT cells have a high background level of exchanges compared to wild type or NBS cells that confounds the understanding of low dose responses. To understand the sensitivity differences for high to low doses, chromosomal aberration analysis was first performed at low dose-rates (0.5 Gy/d), and results provided further evidence for the lack of sensitivity for exchanges in AT cells below doses of 1 Gy. Normal lung fibroblast cells treated with KU-55933, a specific ATM kinase inhibitor, showed increased numbers of exchanges at a dose of 1 Gy and higher, but were similar to wild type cells at 0.5 Gy or below. These results were confirmed using siRNA knockdown of ATM. The present study provides evidence that the increased radiation sensitivity of AT cells for chromosomal exchanges found at high dose does not occur at low dose.

  13. Exposure to low-dose barium by drinking water causes hearing loss in mice.

    Science.gov (United States)

    Ohgami, Nobutaka; Hori, Sohjiro; Ohgami, Kyoko; Tamura, Haruka; Tsuzuki, Toyonori; Ohnuma, Shoko; Kato, Masashi

    2012-10-01

    We continuously ingest barium as a general element by drinking water and foods in our daily life. Exposure to high-dose barium (>100mg/kg/day) has been shown to cause physiological impairments. Direct administration of barium to inner ears by vascular perfusion has been shown to cause physiological impairments in inner ears. However, the toxic influence of oral exposure to low-dose barium on hearing levels has not been clarified in vivo. We analyzed the toxic influence of oral exposure to low-dose barium on hearing levels and inner ears in mice. We orally administered barium at low doses of 0.14 and 1.4 mg/kg/day to wild-type ICR mice by drinking water. The doses are equivalent to and 10-fold higher than the limit level (0.7 mg/l) of WHO health-based guidelines for drinking water, respectively. After 2-week exposure, hearing levels were measured by auditory brain stem responses and inner ears were morphologically analyzed. After 2-month exposure, tissue distribution of barium was measured by inductively coupled plasma mass spectrometry. Low-dose barium in drinking water caused severe hearing loss in mice. Inner ears including inner and outer hair cells, stria vascularis and spiral ganglion neurons showed severe degeneration. The Barium-administered group showed significantly higher levels of barium in inner ears than those in the control group, while barium levels in bone did not show a significant difference between the two groups. Barium levels in other tissues including the cerebrum, cerebellum, heart, liver and kidney were undetectably low in both groups. Our results demonstrate for the first time that low-dose barium administered by drinking water specifically distributes to inner ears resulting in severe ototoxicity with degeneration of inner ears in mice. Copyright © 2012 Elsevier Inc. All rights reserved.

  14. Validation of a low dose simulation technique for computed tomography images.

    Directory of Open Access Journals (Sweden)

    Daniela Muenzel

    Full Text Available PURPOSE: Evaluation of a new software tool for generation of simulated low-dose computed tomography (CT images from an original higher dose scan. MATERIALS AND METHODS: Original CT scan data (100 mAs, 80 mAs, 60 mAs, 40 mAs, 20 mAs, 10 mAs; 100 kV of a swine were acquired (approved by the regional governmental commission for animal protection. Simulations of CT acquisition with a lower dose (simulated 10-80 mAs were calculated using a low-dose simulation algorithm. The simulations were compared to the originals of the same dose level with regard to density values and image noise. Four radiologists assessed the realistic visual appearance of the simulated images. RESULTS: Image characteristics of simulated low dose scans were similar to the originals. Mean overall discrepancy of image noise and CT values was -1.2% (range -9% to 3.2% and -0.2% (range -8.2% to 3.2%, respectively, p>0.05. Confidence intervals of discrepancies ranged between 0.9-10.2 HU (noise and 1.9-13.4 HU (CT values, without significant differences (p>0.05. Subjective observer evaluation of image appearance showed no visually detectable difference. CONCLUSION: Simulated low dose images showed excellent agreement with the originals concerning image noise, CT density values, and subjective assessment of the visual appearance of the simulated images. An authentic low-dose simulation opens up opportunity with regard to staff education, protocol optimization and introduction of new techniques.

  15. A model for inverse dose-rate effects - low dose-rate hyper-sensibility in response to targeted radionuclide therapy

    International Nuclear Information System (INIS)

    Murray, I.; Mather, S.J.

    2015-01-01

    Full text of publication follows. The aim of this work was to test the hypothesis that the Linear-Quadratic (LQ) model of cell survival, developed for external beam radiotherapy (EBRT), could be extended to targeted radionuclide therapy (TRT) in order to predict dose-response relationships in a cell line exhibiting low dose hypersensitivity (LDH). Methods: aliquots of the PC-3 cancer cell line were treated with either EBRT or an in-vitro model of TRT (Irradiation of cell culture with Y-90 EDTA over 24, 48, 72 or 96 hours). Dosimetry for the TRT was calculated using radiation transport simulations with the Monte Carlo PENELOPE code. Clonogenic as well as functional biological assays were used to assess cell response. An extension of the LQ model was developed which incorporated a dose-rate threshold for activation of repair mechanisms. Results: accurate dosimetry for in-vitro exposures of cell cultures to radioactivity was established. LQ parameters of cell survival were established for the PC-3 cell line in response to EBRT. The standard LQ model did not predict survival in PC-3 cells exposed to Y 90 irradiation over periods of up to 96 hours. In fact cells were more sensitive to the same dose when irradiation was carried out over 96 hours than 24 hours. I.e. at a lower dose-rate. Deviations from the LQ predictions were most pronounced below a threshold dose-rate of 0.5 Gy/hr. These results led to an extension of the LQ model based upon a dose-rate dependent sigmoid model of single strand DNA repair. This extension to the model resulted in predicted cell survival curves that closely matched the experimental data. Conclusion: the LQ model of cell survival to radiation has been shown to be largely predictive of response to low dose-rate irradiation. However, in cells displaying LDH, further adaptation of the model was required. (authors)

  16. Incidence of hypersensitivity and anaphylaxis with sugammadex.

    Science.gov (United States)

    Min, K Chris; Woo, Tiffany; Assaid, Christopher; McCrea, Jacqueline; Gurner, Deborah M; Sisk, Christine McCrary; Adkinson, Franklin; Herring, W Joseph

    2018-06-01

    To evaluate the incidence of hypersensitivity and anaphylaxis after administration of sugammadex. Retrospective analysis. Sugammadex clinical development program and post-marketing experience. Surgical patients and healthy volunteers who received sugammadex or placebo/comparator with anesthesia and/or neuromuscular blockade (NMB). Sugammadex administered as 2.0 mg/kg at reappearance of the second twitch, 4.0 mg/kg at 1-2 post-tetanic count, or 16.0 mg/kg at 3 min after rocuronium 1.2 mg/kg. Three analytical methods were used: 1) automated MedDRA queries; 2) searches of adverse events (AEs) consistent with treatment-related hypersensitivity reactions as diagnosed by the investigator; and 3) a retrospective adjudication of AEs suggestive of hypersensitivity by a blinded, independent adjudication committee (AC). In addition, a search of all post-marketing reports of events of hypersensitivity was performed, and events were retrospectively adjudicated by an independent AC. Anaphylaxis was determined according to Sampson Criterion 1. The pooled dataset included 3519 unique subjects who received sugammadex and 544 who received placebo. The automated MedDRA query method showed no apparent increase in hypersensitivity or anaphylaxis with sugammadex as compared to placebo or neostigmine. Similarly, there was a low overall incidence of AEs of treatment-related hypersensitivity (sugammadex and placebo or neostigmine. Finally, the retrospective adjudication of AEs suggestive of hypersensitivity showed a low incidence of hypersensitivity (0.56% and 0.21% for sugammadex 2 mg/kg and 4 mg/kg, respectively), with an incidence similar to subjects who received placebo (0.55%). There were no confirmed cases of anaphylaxis in the pooled studies. During post-marketing use, spontaneous reports of anaphylaxis occurred with approximately 0.01% of sugammadex doses. Subjects who received sugammadex with general anesthesia and/or NMB had a low overall incidence of

  17. Death penalty for keratinocytes: apoptosis versus cornification.

    Science.gov (United States)

    Lippens, S; Denecker, G; Ovaere, P; Vandenabeele, P; Declercq, W

    2005-11-01

    Homeostasis implies a balance between cell growth and cell death. This balance is essential for the development and maintenance of multicellular organisms. Homeostasis is controlled by several mechanisms including apoptosis, a process by which cells condemned to death are completely eliminated. However, in some cases, total destruction and removal of dead cells is not desirable, as when they fulfil a specific function such as formation of the skin barrier provided by corneocytes, also known as terminally differentiated keratinocytes. In this case, programmed cell death results in accumulation of functional cell corpses. Previously, this process has been associated with apoptotic cell death. In this overview, we discuss differences and similarities in the molecular regulation of epidermal programmed cell death and apoptosis. We conclude that despite earlier confusion, apoptosis and cornification occur through distinct molecular pathways, and that possibly antiapoptotic mechanisms are implicated in the terminal differentiation of keratinocytes.

  18. Culture technique of rabbit primary epidermal keratinocytes

    Directory of Open Access Journals (Sweden)

    Marini M

    2012-10-01

    Full Text Available The epidermis is the protective covering outer layer of the mammalian skin. The epidermal cells are stratified squamous epithelia which undergo continuous differentiation of loss and replacement of cells. Ninety per cent of epidermal cells consist of keratinocytes that are found in the basal layer of the stratified epithelium called epidermis. Keratinocytes are responsible for forming tight junctions with the nerves of the skin as well as in the process of wound healing. This article highlights the method of isolation and culture of rabbit primary epidermal keratinocytes in vitro. Approximately 2cm x 2cm oval shaped line was drawn on the dorsum of the rabbit to mark the surgical area. Then, the skin was carefully excised using a surgical blade and the target skin specimens harvested from the rabbits were placed in transport medium comprising of Dulbecco’s Modified Eagle Medium (DMEM and 1% of antibiotic-antimycotic solution. The specimens were transferred into a petri dish containing 70% ethanol and washed for 5 min followed by a wash in 1 x Dulbecco’s Phosphate Buffered Saline (DBPS. Then, the skin specimens were placed in DMEM and minced into small pieces using a scalpel. The minced pieces were placed in a centrifuge tube containing 0.6% Dispase and 1% antibiotic-antimycotic solution overnight at 4°C in a horizontal orientation. The epidermis layer (whitish, semi-transparent was separated from the dermis (pink, opaque, gooey with the aid of curved forceps by fixing the dermis with one pair of forceps while detaching the epidermis with the second pair. The cells were cultured at a density of 4 x 104 cells/cm2 in culture flask at 37°C and 5% CO2. The cell morphology of the keratinocytes was analyzed using inverted microscope.

  19. induction of cytogenetic damage by low doses of acute and chronic gamma-radiation in mammalian and plant cells

    International Nuclear Information System (INIS)

    Zaichkina, S.I.; Aptikaeva, G.F.; Akhmadieva, A.Ch.; Rozanova, O.M.; Smirnova, E.N.; Rogova, N.J.; Ganassi, E.E.

    1997-01-01

    The problem of the biological action of low doses of mutagenic agents has received much attention recently. It is shown that the risk factors for low-dose exposure are greater that it was calculated by extrapolation from higher to lower doses. The aim of the present study was to investigate the effect of low doses on various biological objects including animal and plant cells. (authors)

  20. Induction of cytogenetic damage by low doses of acute and chronic gamma-radiation in mammalian and plant cells

    Energy Technology Data Exchange (ETDEWEB)

    Zaichkina, S.I.; Aptikaeva, G.F.; Akhmadieva, A.Ch.; Rozanova, O.M.; Smirnova, E.N.; Rogova, N.J.; Ganassi, E.E. [Institute of Theoretical and Experimental Biophysics, Moscow (Russian Federation)

    1997-03-01

    The problem of the biological action of low doses of mutagenic agents has received much attention recently. It is shown that the risk factors for low-dose exposure are greater that it was calculated by extrapolation from higher to lower doses. The aim of the present study was to investigate the effect of low doses on various biological objects including animal and plant cells. (authors)

  1. Human keratinocyte sensitivity towards inflammatory cytokines varies with culture time

    Directory of Open Access Journals (Sweden)

    G. Elliott

    1992-01-01

    Full Text Available Proliferating keratinocyte cultures have been reported to synthesize higher concentrations of prostaglandin (PG E than confluent ones. As interleukin-1 (IL-1 stimulates keratinocyte PGE synthesis we investigated whether the degree of confluency of the keratinocyte culture modified the response of the cells to IL-1. It was found that IL-1α (100 U/ml stimulated PGE2 synthesis by proliferating (7 days in culture but not differentiating (14 days in culture keratinocytes. Similar effects were observed using tumour necrosis factor-α. Both arachidonic acid (AA and the calcium ionophore A23187 stimulated PGE2 synthesis by 7 and 14 day cultures although the increase was greatest when 7 day cultures were used. Our data indicate that there is a specific down-regulation of the mechanism(s by which some inflammatory cytokines stimulate keratinocyte eicosanoid synthesis as cultured keratinocytes begin to differentiate.

  2. Final Report - Epigenetics of low dose radiation effects in an animal model

    Energy Technology Data Exchange (ETDEWEB)

    Kovalchuk, Olga

    2014-10-22

    This project sought mechanistic understanding of the epigenetic response of tissues as well as the consequences of those responses, when induced by low dose irradiation in a well-established model system (mouse). Based on solid and extensive preliminary data we investigated the molecular epigenetic mechanisms of in vivo radiation responses, particularly – effects of low, occupationally relevant radiation exposures on the genome stability and adaptive response in mammalian tissues and organisms. We accumulated evidence that low dose irradiation altered epigenetic profiles and impacted radiation target organs of the exposed animals. The main long-term goal was to dissect the epigenetic basis of induction of the low dose radiation-induced genome instability and adaptive response and the specific fundamental roles of epigenetic changes (i.e. DNA methylation, histone modifications and miRNAs) in their generation. We hypothesized that changes in global and regional DNA methylation, global histone modifications and regulatory microRNAs played pivotal roles in the generation and maintenance low-dose radiation-induced genome instability and adaptive response. We predicted that epigenetic changes influenced the levels of genetic rearrangements (transposone reactivation). We hypothesized that epigenetic responses from low dose irradiation were dependent on exposure regimes, and would be greatest when organisms are exposed in a protracted/fractionated manner: fractionated exposures > acute exposures. We anticipated that the epigenetic responses were correlated with the gene expression levels. Our immediate objectives were: • To investigate the exact nature of the global and locus-specific DNA methylation changes in the LDR exposed cells and tissues and dissect their roles in adaptive response • To investigate the roles of histone modifications in the low dose radiation effects and adaptive response • To dissect the roles of regulatory microRNAs and their targets in low

  3. Health effects of low doses at low dose rates: dose-response relationship modeling in a cohort of workers of the nuclear industry

    International Nuclear Information System (INIS)

    Metz-Flamant, Camille

    2011-01-01

    The aim of this thesis is to contribute to a better understanding of the health effects of chronic external low doses of ionising radiation. This work is based on the French cohort of CEA-AREVA NC nuclear workers. The mains stages of this thesis were (1) conducting a review of epidemiological studies on nuclear workers, (2) completing the database and performing a descriptive analysis of the cohort, (3) quantifying risk by different statistical methods and (4) modelling the exposure-time-risk relationship. The cohort includes monitored workers employed more than one year between 1950 and 1994 at CEA or AREVA NC companies. Individual annual external exposure, history of work, vital status and causes of death were reconstructed for each worker. Standardized mortality ratios using French national mortality rates as external reference were computed. Exposure-risk analysis was conducted in the cohort using the linear excess relative risk model, based on both Poisson regression and Cox model. Time dependent modifying factors were investigated by adding an interaction term in the model or by using exposure time windows. The cohort includes 36, 769 workers, followed-up until age 60 in average. During the 1968- 2004 period, 5, 443 deaths, 2, 213 cancers, 62 leukemia and 1, 314 cardiovascular diseases were recorded. Among the 57% exposed workers, the mean cumulative dose was 21.5 milli-sieverts (mSv). A strong Healthy Worker Effect is observed in the cohort. Significant elevated risks of pleura cancer and melanoma deaths were observed in the cohort but not associated with dose. No significant association was observed with solid cancers, lung cancer and cardiovascular diseases. A significant dose-response relationship was observed for leukemia excluding chronic lymphatic leukemia, mainly for doses received less than 15 years before and for yearly dose rates higher than 10 mSv. This PhD work contributes to the evaluation of risks associated to chronic external radiation

  4. Pharmacokinetic properties and tolerability of low-dose SoluMatrix diclofenac.

    Science.gov (United States)

    Desjardins, Paul J; Olugemo, Kemi; Solorio, Daniel; Young, Clarence L

    2015-02-01

    This study compared the pharmacokinetic properties and safety profile of low-dose (18- and 35-mg) diclofenac capsules manufactured using SoluMatrix Fine Particle Technology (Trademark of iCeutica Inc. (Philadelphia, Pennsylvania), and the technology is licensed to Iroko Pharmaceuticals, LLC (Philadelphia, Pennsylvania) for exclusive use in NSAIDs), which produces submicron-sized drug particles with enhanced dissolution properties, to those of diclofenac potassium immediate-release (IR) 50-mg tablets. This Phase 1, single-center, randomized, open-label, single-dose crossover study was conducted in 40 healthy volunteers. Subjects received, in randomized order, SoluMatrix diclofenac 18- or 35-mg capsules in the fasting condition, SoluMatrix diclofenac 35-mg capsules under fed conditions, and diclofenac potassium IR 50-mg tablets under fasting and fed conditions. Pharmacokinetic parameters (T(max), C(max), AUC(0-t), AUC(0-∞)) were calculated from the concentrations of diclofenac in the plasma. Absorption, food effect, and dose proportionality were determined using a mixed-model ANOVA for C(max), AUC(0-t), AUC(0-∞). Tolerability was assessed by recording adverse events, physical examination findings, vital sign measurements: clinical laboratory test results. Overall, 35 healthy volunteers aged 18 to 52 years completed the study. The mean age of the subjects was 33.4 years, and approximately half were men (47.5%). Median T(max) values were similar between the low-dose SoluMatrix diclofenac 35-mg capsules and the diclofenac potassium IR 50-mg tablets (both, ~1.0 hour). The mean maximum plasma concentration (C(max)) after the administration of low-dose SoluMatrix diclofenac 35-mg capsules was 26% lower than that with diclofenac potassium IR 50-mg tablets under fasting conditions (868.72 vs 1194.21 ng/mL). The administration of low-dose SoluMatrix diclofenac 35-mg capsules was associated with a 23% lower overall systemic exposure compared with that of diclofenac

  5. Cytogenetic damage at low doses and the problem of bioindication of chronic low level radiation exposure

    International Nuclear Information System (INIS)

    Geras'kin, S.A.; Dikarev, V.G.; Nesterov, E.B.; Vasiliev, D.V.; Dikareva, N.S.

    2000-01-01

    The analysis undertaken by us of the experimentally observed cellular responses to low dose irradiation has shown that the relationship between the yield of induced cytogenetic damage and radiation dose within low dose range is non-linear and universal in character. Because of the relationship between the yield of cytogenetic damage and dose within low dose range is non-linear, the aberration frequency cannot be used in biological dosimetry in the most important in terms of practical application case. The cytogenetic damage frequency cannot be used in biological dosimetry also because of the probability of synergistic and antagonistic interaction effects of the different nature factors simultaneously acting on test-object in real conditions is high within low dose (concentration) range. In our experimental study of the regularities in the yield of structural mutations in conditions of combined influence of ionizing radiation, heavy metals and pesticides it was found that synergistic and antagonistic effects are mainly induced in conditions of combined action of low exposure injuring agents. Experiments on agricultural plants were carried out in 1986-1989 at the 30-km zone around Chernobyl NPP. It was shown that chronic low dose exposure could cause an inheritable destabilization of genetic structures expressing in increase of cytogenetic damage and yield karyotypic variability in offspring's of irradiated organisms. Obviously exactly this circumstance is the reason of the phenomenon found in our researches of significant time delay of cytogenetic damage reduction rate from radioactive pollution reduction rate from time past from the accident moment. Research of cytogenetic damage of reproductive (seeds) and vegetative (needles) plant organs of the Pinus sylvestris tree micropopulations growing in contrast by radioactive pollution level sites of the 30-km ChNPP zone and also in the vicinity of the industrial plant > for processing and temporary storage of

  6. RISC-RAD. A European integrated approach to the problem of low doses

    International Nuclear Information System (INIS)

    Meunier, A.; Sabatier, L.; Atkinson, M.; Paretzke, H.; Bouffler, S.; Mullenders, L.

    2007-01-01

    Complete text of publication follows. Funded by the European Commission in the framework of a dedicated programme supporting research in the Nuclear sector (FP6 Euratom), the project RISC-RAD undertakes experimental and modelling studies ultimately to improve low dose radiation cancer risk assessment by exploring and providing evidence for the most appropriate radiation cancer risk projection and interpolation models. It started on 1st January 2004 and is running until 31 st October 2008. It mobilizes a consortium of 31 partners and is coordinated by Dr. Laure Sabatier from the French atomic energy commission. Indeed the project represents an unprecedented attempt to integrate horizontally the research on the effects of low doses of IR at the European level. A multipartner project supporting objective-driven research, RISC-RAD aims at contributing to bridge the remaining gap of scientific knowledge about effects of lows doses of ionizing radiation. It spans a large part of the research spectrum, including many topics addressed during the LOWRAD2007 conference. This presentation intends to give an account of the integrative aspects of the project, insights on the innovative solutions found to approach a complex and controversial scientific topic like the biological effects of low doses of ionizing radiation, and links with some areas of social studies on science.The concept of 'integration' implies the development of a new kind of activity in the research field, which crosses its traditional boundaries : controversies of several kinds must temporarily be overcome within the project management board in order to define and follow a common strategy. Among them, how to reconcile the creative part of fundamental research with the compliance to strict project planning rules has come up as a debate which questions the best way a significant collective and coordinated action can address the issue of the low dose cancer risk assessment on the long term. The knowledge and

  7. Clarithromycin (Biaxin)-lenalidomide-low-dose dexamethasone (BiRd) versus lenalidomide-low-dose dexamethasone (Rd) for newly diagnosed myeloma.

    Science.gov (United States)

    Gay, Francesca; Rajkumar, S Vincent; Coleman, Morton; Kumar, Shaji; Mark, Tomer; Dispenzieri, Angela; Pearse, Roger; Gertz, Morie A; Leonard, John; Lacy, Martha Q; Chen-Kiang, Selina; Roy, Vivek; Jayabalan, David S; Lust, John A; Witzig, Thomas E; Fonseca, Rafael; Kyle, Robert A; Greipp, Philip R; Stewart, A Keith; Niesvizky, Ruben

    2010-09-01

    The objective of this case-matched study was to compare the efficacy and toxicity of the addition of clarithromycin (Biaxin) to lenalidomide/low-dose dexamethasone (BiRd) vs. lenalidomide/low-dose dexamethasone (Rd) for newly diagnosed myeloma. Data from 72 patients treated at the New York Presbyterian Hospital-Cornell Medical Center were retrospectively compared with an equal number of matched pair mates selected among patients seen at the Mayo Clinic who received Rd. Case matching was blinded and was performed according to age, gender, and transplant status. On intention-to-treat analysis, complete response (45.8% vs. 13.9%, P < 0.001) and very-good-partial-response or better (73.6% vs. 33.3%, P < 0.001) were significantly higher with BiRd. Time-to-progression (median 48.3 vs. 27.5 months, P = 0.071), and progression-free survival (median 48.3 vs. 27.5 months, P = 0.044) were higher with BiRd. There was a trend toward better OS with BiRd (3-year OS: 89.7% vs. 73.0%, P = 0.170). Main grade 3-4 toxicities of BiRd were hematological, in particular thrombocytopenia (23.6% vs. 8.3%, P = 0.012). Infections (16.7% vs. 9.7%, P = 0.218) and dermatological toxicity (12.5% vs. 4.2%, P = 0.129) were higher with Rd. Results of this case-matched analysis suggest that there is significant additive value when clarithromycin is added to Rd. Randomized phase III trials are needed to confirm these results. © 2010 Wiley-Liss, Inc.

  8. Stimulation effect of early growth in crops by low dose radiation

    International Nuclear Information System (INIS)

    Kim, J.S.; Song, H.S.; Kim, J.K.; Lee, Y.K.; Lee, Y.B.

    1998-01-01

    Germination rate and early growth in crop such as rice,soybean,and perilla were observed after irradiation of γ-ray (Co-60) in order to determine the effects of low does radiation. The low dose radiation was able to improve the early growth in crops and their agricultural characters. Germination rate of 2Gy-irradiatied rice seeds was high and also were seeding height and fresh weight of the 0.5 Gy-irradiated. Germination rate and early growth of soybean were high in 4Gy-irradiated group. Perilla gew of so promisingly after after low dose irradiation, however there slightly increasing effects on germination rate, seeding height and fresh weight at 2Gt-, 1Gy-, and 1Gy irradiated group, respectively. (author)

  9. Low-dose budesonide treatment improves lung function in patients with infrequent asthma symptoms at baseline

    DEFF Research Database (Denmark)

    Reddel, H. K.; Busse, W. W.; Pedersen, Søren

    2015-01-01

    symptom frequency groups (Figure). CONCLUSIONS: Long-term, once-daily, low-dose budesonide treatment plus usual asthma medication improves lung function in patients with mild, recent-onset asthma. These beneficial effects were seen even in patients with the lowest baseline asthma symptom frequency (0......RATIONALE: Inhaled corticosteroids (ICS) are highly effective in low doses for improving asthma outcomes, including lung function. In the past, ICS treatment was recommended for patients with 'persistent' asthma, defined by symptoms >2 days/week.1 However, evidence is lacking for the benefit of ICS...... in patients with less frequent symptoms at presentation. This was investigated in a post-hoc analysis of the multinational inhaled Steroid Treatment As Regular Therapy in early asthma (START) study.2 METHODS: Patients aged 4-66 years (median 21 years) with a history of recent-onset mild asthma (11 years...

  10. Smoking habits in the randomised Danish Lung Cancer Screening Trial with low-dose CT

    DEFF Research Database (Denmark)

    Ashraf, Haseem; Saghir, Zaigham; Dirksen, Asger

    2014-01-01

    BACKGROUND: We present the final results of the effect of lung cancer screening with low-dose CT on the smoking habits of participants in a 5-year screening trial. METHODS: The Danish Lung Cancer Screening Trial (DLCST) was a 5-year screening trial that enrolled 4104 subjects; 2052 were randomised...... to annual low-dose CT (CT group) and 2052 received no intervention (control group). Participants were current and ex-smokers (≥4 weeks abstinence from smoking) with a tobacco consumption of ≥20 pack years. Smoking habits were determined annually. Missing values for smoking status at the final screening...... round were handled using two different models. RESULTS: There were no statistically significant differences in annual smoking status between the CT group and control group. Overall the ex-smoker rates (CT + control group) significantly increased from 24% (baseline) to 37% at year 5 of screening (p

  11. Microdose acquisition in adolescent leg length discrepancy using a low-dose biplane imaging system

    DEFF Research Database (Denmark)

    Jensen, Janni; Mussmann, Bo Redder; Hjarbæk, John

    2017-01-01

    To compare leg length measurements performed on diagnostic images and low dose preview images both acquired using a low-dose bi-planar imaging system. Material and Methods Preview and diagnostic images from 22 patients were retrospectively collected (14 girls, 8 boys; mean age, 12.8 years; age range, 10......-15 years). All images were anonymized and measured independently by two musculoskeletal radiologists. Three sets of measurements were performed on all images; the mechanical axis lines of the femur and the tibia as well as the anatomical line of the entire extremity. Statistical significance was tested...... with a paired t-test. Results No statistically significant difference was found between measurements performed on the preview and on the diagnostic image. The mean tibial length difference between the observers was -0.06 cm (95% confidence interval [CI], -0.12 to 0.01) and -0.08 cm (95% CI, -0.21 to 0...

  12. Ultra-low-dose continuous combined estradiol and norethisterone acetate: improved bleeding profile in postmenopausal women

    DEFF Research Database (Denmark)

    Sturdee, D.W.; Archer, D.F.; Rakov, V.

    2008-01-01

    OBJECTIVE: To evaluate the effect of two ultra-low-dose hormone treatments containing estradiol (E2) 0.5 mg and norethisterone acetate (NETA) 0.1 or 0.25 mg on the endometrium and bleeding. METHODS: A prospective, randomized, placebo-controlled trial of 6 months. Local Ethics Committee approval...... and informed consent were obtained prior to initiation and enrollment. Out of 577 postmenopausal women randomized, 575 took E2/NETA 0.1 (n = 194), or E2/NETA 0.25 (n = 181) or placebo (n = 200). Endometrial bleeding was monitored by daily diary cards and endometrial thickness by transvaginal ultrasound......: The ultra-low-dose combination of E2/NETA 0.1 or E2/NETA 0.25 resulted in a high incidence of amenorrhea and no bleeding in postmenopausal women, and a corresponding high level of compliance. Overall, there was no significant change in mean endometrial thickness during 6 months of active treatment...

  13. Studies on adaptive response of lymphocyte transformation induced by low-dose irradiation

    International Nuclear Information System (INIS)

    Du Zeji; Su Liaoyuan; Tian Hailin; Zou Huawei

    1995-10-01

    Human peripheral blood lymphocytes stimulated by mitogen in vitro for 24 h were exposed to low-dose γ-ray irradiation (0.5∼4.0 cGy, adaptive dose). They showed an adaptive response to the inhibition of 3 H-TdR incorporation by subsequent higher acute doses of γ-ray (challenge dose). At the interval of 24 h between adaptive dose and challenge dose, the strongest adaptive response induced by low-dose irradiation was found. It is also found that the response induced by 1.0 cGy of adaptive dose was more obvious than that by other doses and that 3.0 Gy of challenge dose produced the strongest adaptive response. As the challenge doses increased, the adaptive response reduced. (2 figs., 2 tabs.)

  14. Towards robust deconvolution of low-dose perfusion CT: Sparse perfusion deconvolution using online dictionary learning

    Science.gov (United States)

    Fang, Ruogu; Chen, Tsuhan; Sanelli, Pina C.

    2014-01-01

    Computed tomography perfusion (CTP) is an important functional imaging modality in the evaluation of cerebrovascular diseases, particularly in acute stroke and vasospasm. However, the post-processed parametric maps of blood flow tend to be noisy, especially in low-dose CTP, due to the noisy contrast enhancement profile and the oscillatory nature of the results generated by the current computational methods. In this paper, we propose a robust sparse perfusion deconvolution method (SPD) to estimate cerebral blood flow in CTP performed at low radiation dose. We first build a dictionary from high-dose perfusion maps using online dictionary learning and then perform deconvolution-based hemodynamic parameters estimation on the low-dose CTP data. Our method is validated on clinical data of patients with normal and pathological CBF maps. The results show that we achieve superior performance than existing methods, and potentially improve the differentiation between normal and ischemic tissue in the brain. PMID:23542422

  15. Low-dose total skin electron beam therapy for cutaneous lymphoma. Minimal risk of acute toxicities

    Energy Technology Data Exchange (ETDEWEB)

    Kroeger, Kai; Elsayad, Khaled; Moustakis, Christos; Haverkamp, Uwe; Eich, Hans Theodor [University Hospital of Muenster, Department of Radiation Oncology, Muenster (Germany)

    2017-12-15

    Low-dose total skin electron beam therapy (TSEBT) is attracting increased interest for the effective palliative treatment of primary cutaneous T-cell lymphoma (pCTCL). In this study, we compared toxicity profiles following various radiation doses. We reviewed the records of 60 patients who underwent TSEBT for pCTCL between 2000 and 2016 at the University Hospital of Munster. The treatment characteristics of the radiotherapy (RT) regimens and adverse events (AEs) were then analyzed and compared. In total, 67 courses of TSEBT were administered to 60 patients. Of these patients, 34 (51%) received a standard dose with a median surface dose of 30 Gy and 33 patients (49%) received a low dose with the median surface dose of 12 Gy (7 salvage low-dose TSEBT courses were administered to 5 patients). After a median follow-up of 15 months, the overall AE rate was 100%, including 38 patients (57%) with grade 2 and 7 (10%) with grade 3 AEs. Patients treated with low-dose TSEBT had significantly fewer grade 2 AEs than those with conventional dose regimens (33 vs. 79%, P < 0.001). A lower grade 3 AE rate was also observed in patients who had received the low-dose regimen compared to those with the conventional dose regimens (6 vs. 15%, P = 0.78). Multiple/salvage low-dose TSEBT courses were not associated with an increased risk of acute AEs. Low-dose TSEBT regimens are associated with significantly fewer grade 2 acute toxicities compared with conventional doses of TSEBT. Repeated/Salvage low-dose TSEBT, however, appears to be tolerable and can even be applied safely in patients with cutaneous relapses. (orig.) [German] Eine niedrigdosierte Ganzhautelektronenbestrahlung (TSEBT) wird vermehrt zur effektiven palliativen Behandlung von Patienten mit primaer kutanen T-Zell-Lymphomen (pCTCL) eingesetzt. In dieser Studie vergleichen wir die Toxizitaetsprofile verschiedener Dosiskonzepte. Untersucht wurden 60 zwischen 2000 und 2016 am Universitaetsklinikum Muenster mittels TSEBT

  16. The evolutionary reserve cell concept and model of cellular response induced by low doses of radiation

    International Nuclear Information System (INIS)

    Spitkovsky, D.M.; Talyzina, T.A.

    1995-01-01

    The model is based on the concept of programmed initiation of genetic damage in sub-populations of specific evolutionary reserve cells (ERC). The model quantitatively predicts a dose response of genetic lesions at low dose range and furnishes an explanation of the minimum observed in the dose-response curve at doses corresponding to one (on the average) event of energy deposition per ERC. The complex shape of the dose-response curve is demonstrated to result from superposition of processes in different sub-populations within the exposed cell population (at low doses mainly in ERC). Programmed initiation of genetic lesions in ERC requires two hits to cell membrane and probably, at the same time, to the cell nucleus. The equation for dicentric yield in human lymphocytes as a function of dose describes the experimental observations rather well. (Author)

  17. Heart Failure Treated with Low-dose Milrinone in a Full-term Newborn

    Directory of Open Access Journals (Sweden)

    S. Šebková

    2012-01-01

    Full Text Available A term newborn with a hypocontractile myocardium complicating persistent pulmonary hypertension of the newborn was successfully treated with a low-dose phosphodiesterase III inhibitor milrinone. Echocardiography diagnosed heart failure with a left ventricular ejection fraction of 35% and a left ventricular shortening fraction of 18% and severe persistent pulmonary hypertension of the newborn with oxygenation index of 28. Milrinone was started at an initial dose of 50 mcg/kg, followed by continuous infusion of 0.20 mcg/kg/min. With lowdose milrinone oxygenation index decreased to 3 within 6 hours, left ventricular ejection fraction and left ventricular shortening fraction increased to 57%, and 30%, respectively. Low doses of milrinone might be promising in the treatment of heart failure and persistent pulmonary hypertension of the newborn in term newborns.

  18. Heart failure treated with low-dose milrinone in a full-term newborn.

    Science.gov (United States)

    Sebková, S; Tomek, V; Zemanová, P; Janota, J

    2012-01-01

    A term newborn with a hypocontractile myocardium complicating persistent pulmonary hypertension of the newborn was successfully treated with a low-dose phosphodiesterase III inhibitor milrinone. Echocardiography diagnosed heart failure with a left ventricular ejection fraction of 35% and a left ventricular shortening fraction of 18% and severe persistent pulmonary hypertension of the newborn with oxygenation index of 28. Milrinone was started at an initial dose of 50 mcg/kg, followed by continuous infusion of 0.20 mcg/kg/min. With lowdose milrinone oxygenation index decreased to 3 within 6 hours, left ventricular ejection fraction and left ventricular shortening fraction increased to 57%, and 30%, respectively. Low doses of milrinone might be promising in the treatment of heart failure and persistent pulmonary hypertension of the newborn in term newborns.

  19. Inhibition of alloxan diabetes by low dose {gamma}-irradiation before alloxan administration

    Energy Technology Data Exchange (ETDEWEB)

    Yamaoka, Kiyonori [Central Research Inst. of Electric Power Industry, Komae, Tokyo (Japan). Komae Research Lab.; Takehara, Yoshiki; Yoshioka, Tamotsu; Utsumi, Kozo

    1994-10-01

    We evaluated the inhibitory effects of whole body {sup 60}Co-{gamma} irradiation at a single low dose on alloxan-induced hyperglycemia in rats. (1) In rats that received alloxan, SOD activity in pancreas significantly decreased, but the decrease was inhibited by irradiation at a dose of 0.5 Gy. (2) Similarly, plasma peroxide, pancreatic peroxide, and blood glucose increased. However, the increase in pancreatic peroxide was inhibited by irradiation at a dose of 0.5 or 1.0 Gy and the increase in blood glucose by irradiation at 0.5 Gy. (3) After alloxan administration, degranulation was observed in cells, but this was inhibited by irradiation at 0.5 Gy. These results suggest that alloxan diabetes was inhibited by the increase of SOD activity in pancreas after low dose irradiation at 0.5 Gy. (author).

  20. Stimulation growth effect of Eriocheir sinensis treated with low-dose neutron

    International Nuclear Information System (INIS)

    Luo Keyong; Liu Chunquan; Xu Lixin; Peng Zhangji

    2006-01-01

    This paper was dealt with the relationship between biochemical indexes and different growth stages of Eriocheir sinensis megalopa treated with Low-dose Neutron at 55.24 to 73.66 mGy. It showed that some biochemical component indexes were increased, such as-SH group in protain (between 23.40% to 69.59%), albumen (between 4.99% to 22.6%) and Hyp compared with CK. However, free radical level (between 7.67% to 32.68%) and AKP were decreased. The carapace color was turned into darker than that of CK; Antibacterial immunity of younger crab during the growing stage was increased, the body size of treated Eriocheir sinensis megalopa became uniform and early sexual maturity was inhibited in a certain degree with a low dose neutron treatment. (authors)

  1. Low-dose aspirin use and the risk of ovarian cancer in Denmark

    DEFF Research Database (Denmark)

    Baandrup, Lone; Kjaer, S K; Olsen, J H

    2015-01-01

    BACKGROUND: A comprehensive body of evidence has shown that aspirin has cancer-preventive effects, particularly against gastrointestinal cancer, but its effects on the risk of ovarian cancer are less well established. This nationwide case-control study examined the association between low......-dose aspirin and the risk of ovarian cancer. PATIENTS AND METHODS: We identified all patients in the Danish Cancer Registry aged 30-84 years old with a histologically verified first diagnosis of epithelial ovarian cancer during 2000-2011. Each patient was sex- and age-matched to 15 population controls using...... risk-set sampling. Prescription use, comorbidity, reproductive history, and demographic characteristics data were obtained from nationwide registries. The use of low-dose (75-150 mg) aspirin was defined according to the dose as well as the duration and consistency of use. Conditional logistic...

  2. Effects of monophasic low-dose oral contraceptives on fibrin formation and resolution in young women

    DEFF Research Database (Denmark)

    Petersen, K R; Sidelmann, Johannes Jakobsen; Skouby, S O

    1993-01-01

    OBJECTIVE: The purpose of this study was to examine key variables in the regulation of coagulation and fibrinolysis during intake of low-dose oral contraceptives containing newly developed progestogens. STUDY DESIGN: Thirty-four healthy young women were allocated to 12 consecutive cycles of treat......OBJECTIVE: The purpose of this study was to examine key variables in the regulation of coagulation and fibrinolysis during intake of low-dose oral contraceptives containing newly developed progestogens. STUDY DESIGN: Thirty-four healthy young women were allocated to 12 consecutive cycles...... and concentration of plasminogen activator inhibitor. Thrombin-antithrombin III complexes and fibrin degradation products were unchanged, signifying no effect of hormonal intake on the degree of activation of the coagulation system or the efficacy of fibrinolysis. CONCLUSION: The overall dynamic balance between...

  3. [Influence of low doses of ionizing radiation on tenascin expression in hybridoma cell systems].

    Science.gov (United States)

    Lunga, I N

    2003-01-01

    One of the achievements of the modern radiation ecology is the preparation and application of stable eukariotic cell lines to solve various problems occurring under exposure to ionizing radiation, especially to low doses. The detection of onco-fetal protein--tenascin in different embryonic and tumor cells of humans and animals supposes the probability of appropriate gene expression in lymphoid cells, including hybridomal cells. Using the immunochemical method, the study of tenascin expression in two mouse hybridomal lines was carried out. Tenascin was revealed in hybridomal lines MLC-1 and K-48. Further hybridomal cell lines were exposed to X-ray radiation (120 KV) with doses 2.10,15 cGy. The obtained results demonstrated the sensitivity of tenascin expression to low doses of ionizing radiation, that may be used as a convenient model of studying of genotoxic effects of various damaging ionizing agents on a cell level.

  4. Simulating threshold voltage shift of MOS devices due to radiation in the low-dose range

    CERN Document Server

    Wan Xin Heng; Gao Wen Yu; Huang Ru; Wang Yang Yuan

    2002-01-01

    An analytical MOSFET threshold voltage shift model due to radiation in the low-dose range has been developed for circuit simulations. Experimental data in the literature shows that the model predictions are in good agreement. It is simple in functional form and hence computationally efficient. It can be used as a basic circuit simulation tool for analysing MOSFET exposed to a nuclear environment up to about 1 Mrad(Si). In accordance with common believe, radiation induced absolute change of threshold voltage was found to be larger in irradiated PMOS devices. However, if the radiation sensitivity is defined in the way authors did it, the results indicated NMOS rather than PMOS devices are more sensitive, specially at low doses. This is important from the standpoint of their possible application in dosimetry

  5. Effect of low-dose gamma irradiation on storage properties in light salted Pseudosciaena crocea

    International Nuclear Information System (INIS)

    Zhang Xiaoyan; Yang Xianshi; Li Xueying; Guo Quanyou

    2012-01-01

    To explore the preservation effect of γ irradiation on light salted Pseudosciaena crocea, the influence of 1 kGy low-dose γ irradiation on sensory quality, microbiological and chemical quality including TVC, TVB-N and TBARS contents of light salted P. crocea stored at 25 ℃ was discussed. The results showed that the number of total viable counts significantly decreased after irradiation, during the whole storage, the bacteria numbers of light salted P. crocea treated with irradiation were still less than the control. The concentrations of TVB-N was significantly reduced after irradiation, whereas lipid oxidation was less accelerated. The shelf life could be remarkably prolonged after low-dose γ irradiation. While the shelf life of control group were 9 and 11 days, the shelf life of irradiated light salted P. crocea were extended to 16 and 20 days, respectively. The results can provide technical references for commercial application of seafood irradiation. (authors)

  6. Evaluation of low-dose irradiation on microbiological quality of white carrots and string beans

    International Nuclear Information System (INIS)

    Koike, Amanda C.R.; Santillo, Amanda G.; Rodrigues, Flávio T.; Duarte, Renato C.; Villavicencio, Anna Lucia C.H.

    2012-01-01

    The minimally processed food provided the consumer with a product quality, safety and practicality. However, minimal processing of food does not reduce pathogenic population of microorganisms to safe levels. Ionizing radiation used in low doses is effective to maintain the quality of food, reducing the microbiological load but rather compromising the nutritional values and sensory property. The association of minimal processing with irradiation could improve the quality and safety of product. The purpose of this study was to evaluate the effectiveness of low-doses of ionizing radiation on the reduction of microorganisms in minimally processed foods. The results show that the ionizing radiation of minimally processed vegetables could decontaminate them without several changes in its properties.

  7. Evaluation of low-dose irradiation on microbiological quality of white carrots and string beans

    Science.gov (United States)

    Koike, Amanda C. R.; Santillo, Amanda G.; Rodrigues, Flávio T.; Duarte, Renato C.; Villavicencio, Anna Lucia C. H.

    2012-08-01

    The minimally processed food provided the consumer with a product quality, safety and practicality. However, minimal processing of food does not reduce pathogenic population of microorganisms to safe levels. Ionizing radiation used in low doses is effective to maintain the quality of food, reducing the microbiological load but rather compromising the nutritional values and sensory property. The association of minimal processing with irradiation could improve the quality and safety of product. The purpose of this study was to evaluate the effectiveness of low-doses of ionizing radiation on the reduction of microorganisms in minimally processed foods. The results show that the ionizing radiation of minimally processed vegetables could decontaminate them without several changes in its properties.

  8. Long-term follow-up of low-dose external pituitary irradiation for Cushing's disease

    International Nuclear Information System (INIS)

    Littley, M.D.; Shalet, S.M.; Beardwell, C.G.; Ahmed, S.R.; Sutton, M.L.

    1990-01-01

    Twenty-four patients (three male) with Cushing's disease, aged between 11 and 67 years, were treated with low-dose external pituitary irradiation (20 Gy in eight fractions over 10-12 days) and followed for between 13 and 171 months (median 93 months). Eleven patients (46%) went into remission 4-36 months after irradiation, but five subsequently relapsed. In this series, the low incidence of radiation-induced hypopituitarism and absence of other complications attributable to radiotherapy suggest that low-dose pituitary irradiation may be a useful treatment option in selected patients. However, long-term follow-up has demonstrated a high relapse rate and failure to prevent Nelson's syndrome in adrenalectomized patients, indicating that it should not be used as primary treatment in preference to selective adenomectomy. (author)

  9. Focal low-dose rate brachytherapy for the treatment of prostate cancer

    Directory of Open Access Journals (Sweden)

    Tong WY

    2013-09-01

    Full Text Available William Y Tong, Gilad Cohen, Yoshiya Yamada Memorial Sloan-Kettering Cancer Center, Department of Radiation Oncology, New York, NY, USA Abstract: Whole-gland low-dose rate (LDR brachytherapy has been a well-established modality of treating low-risk prostate cancer. Treatment in a focal manner has the advantages of reduced toxicity to surrounding organs. Focal treatment using LDR brachytherapy has been relatively unexplored, but it may offer advantages over other modalities that have established experiences with a focal approach. This is particularly true as prostate cancer is being detected at an earlier and more localized stage with the advent of better detection methods and newer imaging modalities. Keywords: prostate cancer, focal, low dose rate, brachytherapy

  10. Low dose X -ray effects on catalase activity in animal tissue

    Science.gov (United States)

    Focea, R.; Nadejde, C.; Creanga, D.; Luchian, T.

    2012-12-01

    This study was intended to investigate the effect of low-dose X ray-irradiation upon the activity of catalase (CAT) in freshly excised chicken tissues (liver, kidney, brain, muscle). The tissue samples were irradiated with 0.5Gy and 2Gy respectively, in a 6 MV photon beam produced by a clinical linear accelerator (VARIAN CLINAC 2100SC). The dose rate was of 260.88cGy/min. at 100 cm source to sample distance. The catalase level was assayed spectrophotometrically, based on reaction kinetics, using a catalase UV assay kit (SIGMA). Catalase increased activity in various tissue samples exposed to the studied X ray doses (for example with 24 % in the liver cells, pbonds that ensure the specificity of CAT active site) but the resulted balance of the two concurrent processes indicates the cell ability of decomposing the hydrogen peroxide-with benefits for the cell physiology restoration for the chosen low dose radiation.

  11. The effects of low dose ionizing radiation on the development of rat cerebral cortex, (2)

    International Nuclear Information System (INIS)

    Matsushita, Koji

    1993-01-01

    In order to study the molecular mechanisms of neuronal migration on developing rat cerebral cortex, we need a tissue culture system in which neuronal migration can be observed. We prepared a tissue culture system of embryonic rat cerebral cortex starting on embryonic day 16 and cultivating it for 48 hours. The autoradiographic study in this system revealed not only the migration of 3 H-thymidine labeled neurons but also neuronal migration delays from low doses of ionizing radiation of more than 10 cGy. In addition, on immunohistochemical study, cell-cell adhesion molecule N-CAM staining was remarkably decreased in the matrix cell layer. In the tissue culture system where monoclonal anti-N-CAM antibodies were added, neuronal migration delay comparable to that of 20 cGy radiation was found. In conclusion, it was speculated that neuronal migration delay might be caused by disturbed N-CAM synthesis in matrix cells after low dose ionizing radiation. (author)

  12. Clustered DNA damages induced in human hematopoietic cells by low doses of ionizing radiation

    Science.gov (United States)

    Sutherland, Betsy M.; Bennett, Paula V.; Cintron-Torres, Nela; Hada, Megumi; Trunk, John; Monteleone, Denise; Sutherland, John C.; Laval, Jacques; Stanislaus, Marisha; Gewirtz, Alan

    2002-01-01

    Ionizing radiation induces clusters of DNA damages--oxidized bases, abasic sites and strand breaks--on opposing strands within a few helical turns. Such damages have been postulated to be difficult to repair, as are double strand breaks (one type of cluster). We have shown that low doses of low and high linear energy transfer (LET) radiation induce such damage clusters in human cells. In human cells, DSB are about 30% of the total of complex damages, and the levels of DSBs and oxidized pyrimidine clusters are similar. The dose responses for cluster induction in cells can be described by a linear relationship, implying that even low doses of ionizing radiation can produce clustered damages. Studies are in progress to determine whether clusters can be produced by mechanisms other than ionizing radiation, as well as the levels of various cluster types formed by low and high LET radiation.

  13. Inconsistencies and open questions regarding low-dose health effects of ionizing radiation

    International Nuclear Information System (INIS)

    Nussbaum, R.H.; Koehnlein, W.

    1994-01-01

    The state of knowledge of health effects from low-dose exposures to ionizing radiation has recently been reviewed in extensive reports by three prestigious national and international commissions of scientific and medical experts with partially overlapping membership, known by their acronyms UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation), BEIR V (Biological Effects of Ionizing Radiation), and ICRP (International Commission on Radiological Protection). Publication of these reports was followed by a number of summaries in scientific journals, authored by recognized radiation experts, that purport to present a scientific consensus of low-dose effects in a more accessible format for health professionals. A critical comparison between various presentations of accepted views, however, reveals inconsistencies regarding open-quotes establishedclose quotes facts and unsettled questions

  14. Effect of Hashimoto thyroiditis on low-dose radioactive-iodine remnant ablation.

    Science.gov (United States)

    Kwon, Hyungju; Choi, June Young; Moon, Jae Hoon; Park, Hyo Jin; Lee, Won Woo; Lee, Kyu Eun

    2016-04-01

    Radioactive-iodine remnant ablation is an integral part of the papillary thyroid carcinoma (PTC) treatment. Although a minimum dose is usually recommended, there is controversy as to whether the low-dose (1100 MBq) radioactive-iodine remnant ablation is adequate for selected patients. A retrospective cohort study was conducted on 691 patients. Patients with no remnant thyroid on the follow-up whole body scan and low stimulated thyroglobulin (sTg) level (Hashimoto thyroiditis based on histopathology diagnosis (odds ratio [OR] = 3.23; p Hashimoto thyroiditis and elevated sTg are negative predictive factors for successful low-dose radioactive-iodine remnant ablation treatment. An appropriate risk-adjusted approach may improve the efficacy of radioactive-iodine remnant ablation treatment. © 2015 Wiley Periodicals, Inc. Head Neck 38: E730-E735, 2016. © 2015 Wiley Periodicals, Inc.

  15. Radiation retinopathy caused by low dose irradiation and antithyroid drug-induced systemic vasculitis

    International Nuclear Information System (INIS)

    Sonoda, Koh-hei; Ishibashi, Tatsuro

    2005-01-01

    We report on a patient with Graves' disease with radiation retinopathy caused by low-dose irradiation and antithyroid drug-induced antineutrophil cytoplasmic antibody (ANCA)-positive vasculitis. A 38-year-old woman with Graves' disease presented with bilateral blurred vision, micro-aneurysms, telangiectasia, and macular edema. The patient was examined by ophthalmoscopy and fluorescein angiography, and radiation retinopathy was diagnosed. The patient had been treated with low-dose irradiation for her Graves' ophthalmopathy a few years earlier. She also had ANCA-positive vasculitis induced by the antithyroid drug (propylthiouracil, PTU) that had been prescribed for her at that time. Because of multiple avascular areas on both retinas, she was treated by intensive retinal photocoagulation to control progressive retinopathy. The radiation doses used to treat Graves' disease ophthalmopathy are low. Nevertheless, there is still a risk of radiation retinopathy developing in patients with PTU-induced ANCA-positive vasculitis. (author)

  16. Health effects of low-dose radiation: Molecular, cellular, and biosystem response

    International Nuclear Information System (INIS)

    Pollycove, M.; Paperiello, C.J.

    1997-01-01

    Since the fifties, the prime concern of radiation protection has been protecting DNA from damage. UNSCEAR initiated a focus on biosystem response to damage with its 1994 report, ''Adaptive Responses to Radiation of Cells and Organisms''. The DNA damage-control biosystem is physiologically operative on both metabolic and radiation induced damage, both effected predominantly by free radicals. These adaptive responses are suppressed by high-dose and stimulated by low dose radiation. Increased biosystem efficiently reduces the number of mutations that accumulate during a lifetime and decrease DNA damage-control with resultant aging and malignancy. Several statistically significant epidemiologic studies have shown risk decrements of cancer mortality and mortality from all causes in populations exposed to low-dose radiation. Further biologic and epidemiologic research is needed to establish a valid threshold below which risk decrements occur. (author)

  17. High-order noise analysis for low dose iterative image reconstruction methods: ASIR, IRIS, and MBAI

    Science.gov (United States)

    Do, Synho; Singh, Sarabjeet; Kalra, Mannudeep K.; Karl, W. Clem; Brady, Thomas J.; Pien, Homer

    2011-03-01

    Iterative reconstruction techniques (IRTs) has been shown to suppress noise significantly in low dose CT imaging. However, medical doctors hesitate to accept this new technology because visual impression of IRT images are different from full-dose filtered back-projection (FBP) images. Most common noise measurements such as the mean and standard deviation of homogeneous region in the image that do not provide sufficient characterization of noise statistics when probability density function becomes non-Gaussian. In this study, we measure L-moments of intensity values of images acquired at 10% of normal dose and reconstructed by IRT methods of two state-of-art clinical scanners (i.e., GE HDCT and Siemens DSCT flash) by keeping dosage level identical to each other. The high- and low-dose scans (i.e., 10% of high dose) were acquired from each scanner and L-moments of noise patches were calculated for the comparison.

  18. A sub-sampled approach to extremely low-dose STEM

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, A. [OptimalSensing, Southlake, Texas 76092, USA; Duke University, ECE, Durham, North Carolina 27708, USA; Luzi, L. [Rice University, ECE, Houston, Texas 77005, USA; Yang, H. [Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA; Kovarik, L. [Pacific NW National Laboratory, Richland, Washington 99354, USA; Mehdi, B. L. [Pacific NW National Laboratory, Richland, Washington 99354, USA; University of Liverpool, Materials Engineering, Liverpool L69 3GH, United Kingdom; Liyu, A. [Pacific NW National Laboratory, Richland, Washington 99354, USA; Gehm, M. E. [Duke University, ECE, Durham, North Carolina 27708, USA; Browning, N. D. [Pacific NW National Laboratory, Richland, Washington 99354, USA; University of Liverpool, Materials Engineering, Liverpool L69 3GH, United Kingdom

    2018-01-22

    The inpainting of randomly sub-sampled images acquired by scanning transmission electron microscopy (STEM) is an attractive method for imaging under low-dose conditions (≤ 1 e-2) without changing either the operation of the microscope or the physics of the imaging process. We show that 1) adaptive sub-sampling increases acquisition speed, resolution, and sensitivity; and 2) random (non-adaptive) sub-sampling is equivalent, but faster than, traditional low-dose techniques. Adaptive sub-sampling opens numerous possibilities for the analysis of beam sensitive materials and in-situ dynamic processes at the resolution limit of the aberration corrected microscope and is demonstrated here for the analysis of the node distribution in metal-organic frameworks (MOFs).

  19. Inhibition of alloxan diabetes by low dose γ-irradiation before alloxan administration

    International Nuclear Information System (INIS)

    Yamaoka, Kiyonori; Takehara, Yoshiki; Yoshioka, Tamotsu; Utsumi, Kozo.

    1994-01-01

    We evaluated the inhibitory effects of whole body 60 Co-γ irradiation at a single low dose on alloxan-induced hyperglycemia in rats. (1) In rats that received alloxan, SOD activity in pancreas significantly decreased, but the decrease was inhibited by irradiation at a dose of 0.5 Gy. (2) Similarly, plasma peroxide, pancreatic peroxide, and blood glucose increased. However, the increase in pancreatic peroxide was inhibited by irradiation at a dose of 0.5 or 1.0 Gy and the increase in blood glucose by irradiation at 0.5 Gy. (3) After alloxan administration, degranulation was observed in cells, but this was inhibited by irradiation at 0.5 Gy. These results suggest that alloxan diabetes was inhibited by the increase of SOD activity in pancreas after low dose irradiation at 0.5 Gy. (author)

  20. Successful Outcome of Low-Dose S-1 Used to Treat Buccal Squamous Cell Carcinoma

    Directory of Open Access Journals (Sweden)

    Kazuyuki Yusa

    2017-01-01

    Full Text Available This case report describes an 86-year-old woman with dormant right buccal squamous cell carcinoma who was able to maintain a reasonable quality of life after being treated with oral low-dose S-1 (80 mg/day. The treatment regimen started in April 2014 and consisted of two weeks of S-1 followed by a one-week interval. The patient remains on this regimen while maintaining her quality of life and she has been under follow-up as an outpatient for 36 months. The outcomes for this patient indicated that low-dose S-1 is a valid anticancer therapy that may help maintain quality of life for some patients with incurable or dormant cancers.

  1. Low dose radiation enhance the anti-tumor effect of high dose radiation on human glioma cell U251

    International Nuclear Information System (INIS)

    Wang Chang; Wang Guanjun; Tan Yehui; Jiang Hongyu; Li Wei

    2008-01-01

    Objective: To detect the effect on the growth of human glioma cell U251 induced by low dose irradiation and low dose irradiation combined with large dose irradiation. Methods: Human glioma cell line U251 and nude mice carried with human glioma were used. The tumor cells and the mice were treated with low dose, high dose, and low dose combined high dose radiation. Cells growth curve, MTT and flow cytometry were used to detect the proliferation, cell cycle and apoptosis of the cells; and the tumor inhibition rate was used to assess the growth of tumor in vivo. Results: After low dose irradiation, there was no difference between experimental group and control group in cell count, MTT and flow cytometry. Single high dose group and low dose combined high dose group both show significantly the suppressing effect on tumor cells, the apoptosis increased and there was cell cycle blocked in G 2 period, but there was no difference between two groups. In vivo apparent anti-tumor effect in high dose radiation group and the combining group was observed, and that was more significant in the combining group; the prior low dose radiation alleviated the injury of hematological system. There was no difference between single low dose radiation group and control. Conclusions: There is no significant effect on human glioma cell induced by low dose radiation, and low dose radiation could not induce adaptive response. But in vivo experience, low dose radiation could enhance the anti-tumor effect of high dose radiation and alleviated the injury of hematological system. (authors)

  2. Lateral topography for reducing effective dose in low-dose chest CT.

    Science.gov (United States)

    Bang, Dong-Ho; Lim, Daekeon; Hwang, Wi-Sub; Park, Seong-Hoon; Jeong, Ok-man; Kang, Kyung Wook; Kang, Hohyung

    2013-06-01

    The purposes of this study were to assess radiation exposure during low-dose chest CT by using lateral topography and to compare the lateral topographic findings with findings obtained with anteroposterior topography alone and anteroposterior and lateral topography combined. From November 2011 to February 2012, 210 male subjects were enrolled in the study. Age, weight, and height of the men were recorded. All subjects were placed into one of three subgroups based on the type of topographic image obtained: anteroposterior topography, lateral topography, and both anteroposterior and lateral topography. Imaging was performed with a 128-MDCT scanner. CT, except for topography, was the same for all subjects. A radiologist analyzed each image, recorded scan length, checked for any insufficiencies in the FOV, and calculated the effective radiation dose. One-way analysis of variance and multiple comparisons were used to compare the effective radiation exposure and scan length between groups. The mean scan length in the anteroposterior topography group was significantly greater than that of the lateral topography group and the combined anteroposterior and lateral topography group (p topography group (0.735 ± 0.033 mSv) was significantly lower than that for the anteroposterior topography group (0.763 ± 0.038 mSv) and the combined anteroposterior and lateral topography group (0.773 ± 0.038) (p < 0.001). Lateral topographic low-dose CT was associated with a lower effective radiation dose and scan length than either anteroposterior topographic low-dose chest CT or low-dose chest CT with both anteroposterior and lateral topograms.

  3. Why we need new approaches to low-dose risk modeling

    International Nuclear Information System (INIS)

    Alvarez, J.L.; Seiler, F.A.

    1996-01-01

    The linear no-threshold model for radiation effects was introduced as a conservative model for the design of radiation protection programs. The model has persisted not only as the basis for such programs, but has come to be treated as a dogma and is often confused with scientific fact. In this examination a number of serious problems with the linear no-threshold model of radiation carcinogenesis were demonstrated, many of them invalidating the hypothesis. It was shown that the relative risk formalism did not approach 1 as the dose approaches zero. When morality ratios were used instead, the data in the region below 0.3 Sv were systematically below the predictions of the linear model. It was also shown that the data above 0.3 Sv were of little use in formulating a model at low doses. In addition, these data are valid only for doses accumulated at high dose rates, and there is no scientific justification for using the model in low-dose, low-dose-rate extrapolations for purposes of radiation protection. Further examination of model fits to the Japanese survivor data were attempted. Several such models were fit to the data including an unconstrained linear, linear-square root, and Weibull, all of which fit the data better than the relative risk, linear no-threshold model. These fits were used to demonstrate that the linear model systematically over estimates the risk at low doses in the Japanese survivor data set. It is recommended here that an unbiased re-analysis of the data be undertaken and the results used to construct a new model, based on all pertinent data. This model could then form the basis for managing radiation risks in the appropriate regions of dose and dose rate

  4. Edge enhancement algorithm for low-dose X-ray fluoroscopic imaging.

    Science.gov (United States)

    Lee, Min Seok; Park, Chul Hee; Kang, Moon Gi

    2017-12-01

    Low-dose X-ray fluoroscopy has continually evolved to reduce radiation risk to patients during clinical diagnosis and surgery. However, the reduction in dose exposure causes quality degradation of the acquired images. In general, an X-ray device has a time-average pre-processor to remove the generated quantum noise. However, this pre-processor causes blurring and artifacts within the moving edge regions, and noise remains in the image. During high-pass filtering (HPF) to enhance edge detail, this noise in the image is amplified. In this study, a 2D edge enhancement algorithm comprising region adaptive HPF with the transient improvement (TI) method, as well as artifacts and noise reduction (ANR), was developed for degraded X-ray fluoroscopic images. The proposed method was applied in a static scene pre-processed by a low-dose X-ray fluoroscopy device. First, the sharpness of the X-ray image was improved using region adaptive HPF with the TI method, which facilitates sharpening of edge details without overshoot problems. Then, an ANR filter that uses an edge directional kernel was developed to remove the artifacts and noise that can occur during sharpening, while preserving edge details. The quantitative and qualitative results obtained by applying the developed method to low-dose X-ray fluoroscopic images and visually and numerically comparing the final images with images improved using conventional edge enhancement techniques indicate that the proposed method outperforms existing edge enhancement methods in terms of objective criteria and subjective visual perception of the actual X-ray fluoroscopic image. The developed edge enhancement algorithm performed well when applied to actual low-dose X-ray fluoroscopic images, not only by improving the sharpness, but also by removing artifacts and noise, including overshoot. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Low-Dose X-ray CT Reconstruction via Dictionary Learning

    Science.gov (United States)

    Xu, Qiong; Zhang, Lei; Hsieh, Jiang; Wang, Ge

    2013-01-01

    Although diagnostic medical imaging provides enormous benefits in the early detection and accuracy diagnosis of various diseases, there are growing concerns on the potential side effect of radiation induced genetic, cancerous and other diseases. How to reduce radiation dose while maintaining the diagnostic performance is a major challenge in the computed tomography (CT) field. Inspired by the compressive sensing theory, the sparse constraint in terms of total variation (TV) minimization has already led to promising results for low-dose CT reconstruction. Compared to the discrete gradient transform used in the TV method, dictionary learning is proven to be an effective way for sparse representation. On the other hand, it is important to consider the statistical property of projection data in the low-dose CT case. Recently, we have developed a dictionary learning based approach for low-dose X-ray CT. In this paper, we present this method in detail and evaluate it in experiments. In our method, the sparse constraint in terms of a redundant dictionary is incorporated into an objective function in a statistical iterative reconstruction framework. The dictionary can be either predetermined before an image reconstruction task or adaptively defined during the reconstruction process. An alternating minimization scheme is developed to minimize the objective function. Our approach is evaluated with low-dose X-ray projections collected in animal and human CT studies, and the improvement associated with dictionary learning is quantified relative to filtered backprojection and TV-based reconstructions. The results show that the proposed approach might produce better images with lower noise and more detailed structural features in our selected cases. However, there is no proof that this is true for all kinds of structures. PMID:22542666

  6. Low dose vitamin C, vitamin E or L-arginine supplementation and ...

    African Journals Online (AJOL)

    The effect of chronic low-dose supplementation with vitamin C (300mg/day for 6 weeks in adults or 100mg/day for 6 weeks in children) or vitamin E (100 IU/day for 6 weeks in adults) or L-Arginine (1g/day for 6 weeks in adults) in ameliorating the pathophysiology and combating the deleterious effects of sickle cell disease in ...

  7. Evaluation of low dose ionizing radiation effect on some blood components in animal model

    OpenAIRE

    El-Shanshoury, H.; El-Shanshoury, G.; Abaza, A.

    2016-01-01

    Exposure to ionizing radiation is known to have lethal effects in blood cells. It is predicted that an individual may spend days, weeks or even months in a radiation field without becoming alarmed. The study aimed to discuss the evaluation of low dose ionizing radiation (IR) effect on some blood components in animal model. Hematological parameters were determined for 110 animal rats (divided into 8 groups) pre- and post-irradiation. An attempt to explain the blood changes resulting from both ...

  8. Radiation effect and response of DNA synthesis in lymphocytes induced by low dose irradiation

    International Nuclear Information System (INIS)

    Zhao Yujie; Su Liaoyuan; Zou Huawei; Kong Xiangrong

    1999-01-01

    The ability of DNA synthesis in lymphocytes were measured by using 3 H-TdR incorporation method. This method was used to observe the damage of lymphocytes irradiated by several challenge doses (0.5-0.8 Gy) and adaptive response induced by previous low dose irradiation. The results show that DNA synthesis was inhibited by challenge dose of radiation and was adapted by previous 0.048 Gy irradiation

  9. The influence of low doses of ionizing radiation on biological systems

    International Nuclear Information System (INIS)

    Kwiecinska, T.

    1986-11-01

    Recent results concerning possible beneficial effects of low doses of ionizing radiation on biological systems are summarized. It is also pointed out on the basis of existing evidence that harmful effects on living organisms take place not only in the case of excess but also in the case of deficiency of ionizing radiation. Possibility of using radio-enhanced ultralow luminescence for studying hormesis phenomena is discussed. 24 refs., 4 figs. (author)

  10. Microdose acquisition in adolescent leg length discrepancy using a low-dose biplane imaging system.

    Science.gov (United States)

    Jensen, Janni; Mussmann, Bo R; Hjarbæk, John; Al-Aubaidi, Zaid; Pedersen, Niels W; Gerke, Oke; Torfing, Trine

    2017-09-01

    Background Children with leg length discrepancy often undergo repeat imaging. Therefore, every effort to reduce radiation dose is important. Using low dose preview images and noise reduction software rather than diagnostic images for length measurements might contribute to reducing dose. Purpose To compare leg length measurements performed on diagnostic images and low dose preview images both acquired using a low-dose bi-planar imaging system. Material and Methods Preview and diagnostic images from 22 patients were retrospectively collected (14 girls, 8 boys; mean age, 12.8 years; age range, 10-15 years). All images were anonymized and measured independently by two musculoskeletal radiologists. Three sets of measurements were performed on all images; the mechanical axis lines of the femur and the tibia as well as the anatomical line of the entire extremity. Statistical significance was tested with a paired t-test. Results No statistically significant difference was found between measurements performed on the preview and on the diagnostic image. The mean tibial length difference between the observers was -0.06 cm (95% confidence interval [CI], -0.12 to 0.01) and -0.08 cm (95% CI, -0.21 to 0.05), respectively; 0.10 cm (95% CI, 0.02-0.17) and 0.06 cm (95% CI, -0.02 to 0.14) for the femoral measurements and 0.12 cm (95% CI, -0.05 to 0.26) and 0.08 cm (95% CI, -0.02 to 0.19) for total leg length discrepancy. ICCs were >0.99 indicating excellent inter- and intra-rater reliability. Conclusion The data strongly imply that leg length measurements performed on preview images from a low-dose bi-planar imaging system are comparable to measurements performed on diagnostic images.

  11. The effect of well-characterized, very low-dose x-ray radiation on fibroblasts.

    Science.gov (United States)

    Truong, Katelyn; Bradley, Suzanne; Baginski, Bryana; Wilson, Joseph R; Medlin, Donald; Zheng, Leon; Wilson, R Kevin; Rusin, Matthew; Takacs, Endre; Dean, Delphine

    2018-01-01

    The purpose of this study is to determine the effects of low-dose radiation on fibroblast cells irradiated by spectrally and dosimetrically well-characterized soft x-rays. To achieve this, a new cell culture x-ray irradiation system was designed. This system generates characteristic fluorescent x-rays to irradiate the cell culture with x-rays of well-defined energies and doses. 3T3 fibroblast cells were cultured in cups with Mylar® surfaces and were irradiated for one hour with characteristic iron (Fe) K x-ray radiation at a dose rate of approximately 550 μGy/hr. Cell proliferation, total protein analysis, flow cytometry, and cell staining were performed on fibroblast cells to determine the various effects caused by the radiation. Irradiated cells demonstrated increased proliferation and protein production compared to control samples. Flow cytometry revealed that a higher percentage of irradiated cells were in the G0/G1 phase of the cell cycle compared to control counterparts, which is consistent with other low-dose studies. Cell staining results suggest that irradiated cells maintained normal cell functions after radiation exposure, as there were no qualitative differences between the images of the control and irradiated samples. The result of this study suggest that low-dose soft x-ray radiation might cause an initial pause, followed by a significant increase, in proliferation. An initial "pause" in cell proliferation could be a protective mechanism of the cells to minimize DNA damage caused by radiation exposure. The new cell irradiation system developed here allows for unprecedented control over the properties of the x-rays given to the cell cultures. This will allow for further studies on various cell types with known spectral distribution and carefully measured doses of radiation, which may help to elucidate the mechanisms behind varied cell responses to low-dose x-rays reported in the literature.

  12. Low-dose radiation epidemiological studies: an assessment of methodological problems

    International Nuclear Information System (INIS)

    Modan, B.

    1991-01-01

    The present report attempts to assess the problems inherent in the analysis of low dose radiation studies, with emphasis on possible sources of methodological errors in the published data, and the consequent relevance to risk estimates. The published data examined concerned populations exposed to nuclear sources such as fallout, weapons' test or in the vicinity of nuclear reactors, occupational exposure, intra-uterine diagnostic X-rays, scattered radiation following X-ray therapy and background irradiation. (UK)

  13. Cytogenetic investigations of persons exposed to professional chronic low-dose irradiation

    International Nuclear Information System (INIS)

    Rangelov, V.; Mitev, L.; Petrunov, P.; Vesselinova, L.

    2005-01-01

    The problem of long term influence of low-doses occupational irradiation is connected with the real assessment of their consequences. The current cytogenetic investigations were done on persons working under occupational chronic external partial irradiation. Accumulated doses of external irradiation are surveyed. Data give ground for suggestion about the relationship between accumulated dose and chromosomal aberrations. The additional damage factors (diagnostic investigations, chemical substances, tobacco addict) have done the more significant influence upon aberrations appearance increasing

  14. Effect of low dose radiation on somatic intrachromosomal recombination in vivo and in vitro

    International Nuclear Information System (INIS)

    Hooker, A.M.; Cormack, J.; Morley, A.A.; Sykes, P.J.; Bhat, M.

    2003-01-01

    Full text: High doses of ionising radiation are mutagenic in a wide range of mutation assays. The majority of radiation exposure studies in in vivo mouse mutation assays have been performed at high doses, eg greater than 1 Gy. However, these doses are not relevant to the low doses of ionising radiation that the majority of the population might likely come into contact with. Radiation protection levels tend to be based on a simple linear no-threshold model which suggests that any radiation above zero is potentially harmful. The pKZ1 recombination mutagenesis mouse model has proven to be a sensitive assay for the detection of mutations caused by low doses of chemical agents. In pKZ1 mice, somatic intrachromosomal recombination (SICR) inversion events can be detected in cells using histochemistry for the E. coli LacZ transgene. We exposed pKZ1 mice to a single radiation dose ranging from 0.001 to 2 Gy. A significant increase in SICR was observed in spleen at the two highest doses of 0.1 and 2 Gy and a significant reduction in SICR below the endogenous frequency was observed at the two lowest doses of 0.01 and 0.001 Gy. After exposing a pKZ1 cell line to the same dose range, a similar J curve response was observed with significant increases in SICR observed at the 3 highest doses and a significant decrease below the endogenous frequency at the lowest dose (0.001 Gy). The next experiments will be to determine the dose where the SICR frequency returns to the endogenous level. The important question posed by these results is 'Is a reduction below the endogenous SICR level caused by low doses of ionising radiation anti-mutagenic?' Studies now need to be performed to investigate the effect of low doses of radiation on other mutation end-points, and the mechanism for the reduction in SICR

  15. Chronic low dose radiation exposure and oxidative stress in radiation workers

    International Nuclear Information System (INIS)

    Ali, S.S.; Bhatt, M.B.; Kulkarni, MM.; Rajan, R.; Singh, B.B.; Venkataraman, G.

    1996-01-01

    Free radicals have been implicated in the pathogenesis of several human diseases. In this study free radical stress due to low dose chronic radiation exposures of radiation workers was examined as a possible atherogenic risk factor. Data on lipid profiles, lipid peroxidation and reduced glutathione content in blood indicated an absence of correlation with radiation doses up to 125 mSv. (author). 13 refs., 1 fig

  16. Life span and tumorigenesis in mice exposed to continuous low dose-rate gamma-rays

    International Nuclear Information System (INIS)

    Tanaka, Satoshi; Braga-Tanaka III, Ignacia; Takabatake, Takashi; Ichinohe, Kazuaki; Tanaka, Kimio; Matsumoto, Tsuneya; Sato, Fumiaki

    2004-01-01

    Two experiments were conducted to evaluate late biological effects of chronic low dose-rate radiation. 1: Late effects of chronic low dose-rate gamma-ray irradiation on SPF mice, using life span and pathological changes as parameters. Continuous irradiation for approximately 400 days was performed using 137 Cs gamma-rays at dose-rates of 20 mGy/day, 1 mGy/day and 0.05 mGy/day with accumulated doses equivalent to 8000 mGy, 400 mGy and 20 mGy, respectively. All mice were kept until their natural death. Statistical analyses show that the life spans of the both sexes irradiated at 20 mGy/day (p<0.0001) and of females irradiated at 1 mGy/day (p<0.05) were significantly shorter than those of the control group. There was no evidence of lengthened life span in mice continuously exposed to very low dose-rates of gama-rays. Pathodological examinations showed that the most frequently observed lethal neoplasms in males were malignant lymphomas, liver, lung, and soft tissue neoplasms, whereas, in females, malignant lymphomas and soft tissue neoplasms were common. No significant difference in the causes of death and mortality rates between groups. Hematopoietic neoplasms (malignant lymphoma and myeloid leukemia), liver, lung and soft tissue neoplasms, showed a tendency to appear at a younger age in both sexes irradiated at 20 mGy/day. Experiment 2: effects on the progeny of chronic low dose-rate gamma-ray irradiated SPF mice: preliminary study. No significant difference was observed between non-irradiated group and irradiated group with regards to litter size, sex ratio and causes of death in F1 and F2 mice. (author)

  17. Effects of Low Dose DD Radiation on Callus Growth of Lithospermum erythrorhizon S

    International Nuclear Information System (INIS)

    Hwang, H.Y.; Kim, J.S.

    2001-01-01

    The effect of low dose DD-radiation on the callus growth of Lithospermum erythrorhizon S. cultured on different medium and lighting condition was investigated. The 8 Gy irradiation stimulated callus growth on LS medium supplemented with BA 2 mg/L and NAA 2mg/L, however, the growth of callus was more effective on LS medium supplemented with BA 1 mg/L and NAA 1 mg/L under 16 hrs day light

  18. Ultra-low dose of intravitreal bevacizumab in retinopathy of prematurity.

    Science.gov (United States)

    Şahin, A; Gürsel-Özkurt, Z; Şahin, M; Türkcü, F M; Yıldırım, A; Yüksel, H

    2018-05-01

    We aimed to investigate the effectivity of the 0.0625 mg dose of bevacizumab in patients with retinopathy of prematurity (ROP) and compare the results with 0.625 mg dose of intravitreal bevacizumab (IVB) injection. The medical records of the patients with type 1 ROP who received IVB monotherapy were retrospectively reviewed. Demographic and clinical characteristics of the patients were recorded. The patients were classified into two groups with respect to received dose of bevacizumab as follows: group F (n = 46) (full dose of bevacizumab-0.625 mg/0.025 ml) and group L (n = 45) (low dose (one tenth) of bevacizumab-0.0625 mg/0.025 ml). Both treatment dose regimens have similar outcomes. Moreover, the mean retinal vascularization time seemed to be significantly higher in group F compared to group L, 168 ± 65 and 97 ± 29 days, respectively (p < 0.001). Disappearance of plus sign is observed earlier in group F (2.45 ± 1.7 vs 3.66 ± 2.46 days, respectively, p = 0.03). The low dose (0.0625 mg) of IVB treatment was effective as full (0.625 mg) dose in ROP treatment. Moreover, our results showed that low-dose treatment might provide faster retinal vascularization than the regular used dose. On the other hand, disappearance of the plus sign takes longer time in patients treated with low dose compared to eyes treated with full dose of IVB that should be taken into account.

  19. Intracavitary after loading techniques, advantages and disadvantages with high and low dose-rate methods

    International Nuclear Information System (INIS)

    Walstam, Rune

    1980-01-01

    Even though suggested as early as 1903, it is only when suitable sealed gamma sources became available, afterloading methods could be developed for interstitial as well as intracavitary work. Manual afterloading technique can be used only for low dose rate irradiation, while remote controlled afterloading technique can be used for both low and high dose-rate irradiation. Afterloading units used at the Karolinska Institute, Stockholm, are described, and experience of their use is narrated briefly. (M.G.B.)

  20. Subacute Low Dose Nerve Agent Exposure Causes DNA Fragmentation in Guinea Pig Leukocytes

    Science.gov (United States)

    2005-10-01

    1 SUBACUTE LOW DOSE NERVE AGENT EXPOSURE CAUSES DNA FRAGMENTATION IN GUINEA PIG LEUKOCYTES. Jitendra R. Dave1, John R. Moffett1, Sally M...DNA fragmentation in blood leukocytes from guinea pigs by ‘Comet’ assay after exposure to soman at doses ranging from 0.1LD50 to 0.4 LD50, once per...computer. Data obtained for exposure to soman demonstrated significant increases in DNA fragmentation in circulating leukocytes in CWNA treated guinea pigs as

  1. Biological effect of low-dose application beta-radiation on the gingival mucosa of dogs

    International Nuclear Information System (INIS)

    Ippolitov, Yu.A.; Kovtun, N.N.; Timofeev, L.V.

    1999-01-01

    Biological effect of low-dose application beta-radiation on the gingival mucosa of dogs is studied. Obtained data illustrate the interactions between tissues in local exposure of live tissue to beta-radiation and determine the threshold total dose as 400 sGy. Higher doses lead to secondary changes in the gingival mucosa after which the tissue barrier does not recover [ru

  2. Low-dose X-ray CT reconstruction via dictionary learning.

    Science.gov (United States)

    Xu, Qiong; Yu, Hengyong; Mou, Xuanqin; Zhang, Lei; Hsieh, Jiang; Wang, Ge

    2012-09-01

    Although diagnostic medical imaging provides enormous benefits in the early detection and accuracy diagnosis of various diseases, there are growing concerns on the potential side effect of radiation induced genetic, cancerous and other diseases. How to reduce radiation dose while maintaining the diagnostic performance is a major challenge in the computed tomography (CT) field. Inspired by the compressive sensing theory, the sparse constraint in terms of total variation (TV) minimization has already led to promising results for low-dose CT reconstruction. Compared to the discrete gradient transform used in the TV method, dictionary learning is proven to be an effective way for sparse representation. On the other hand, it is important to consider the statistical property of projection data in the low-dose CT case. Recently, we have developed a dictionary learning based approach for low-dose X-ray CT. In this paper, we present this method in detail and evaluate it in experiments. In our method, the sparse constraint in terms of a redundant dictionary is incorporated into an objective function in a statistical iterative reconstruction framework. The dictionary can be either predetermined before an image reconstruction task or adaptively defined during the reconstruction process. An alternating minimization scheme is developed to minimize the objective function. Our approach is evaluated with low-dose X-ray projections collected in animal and human CT studies, and the improvement associated with dictionary learning is quantified relative to filtered backprojection and TV-based reconstructions. The results show that the proposed approach might produce better images with lower noise and more detailed structural features in our selected cases. However, there is no proof that this is true for all kinds of structures.

  3. Low doses of six toxicants change plant size distribution in dense populations of Lactuca sativa.

    Science.gov (United States)

    Belz, Regina G; Patama, Marjo; Sinkkonen, Aki

    2018-08-01

    Toxicants are known to have negligible or stimulatory, i.e. hormetic, effects at low doses below those that decrease the mean response of a plant population. Our earlier observations indicated that at such low toxicant doses the growth of very fast- and slow-growing seedlings is selectively altered, even if the population mean remains constant. Currently, it is not known how common these selective low-dose effects are, whether they are similar among fast- and slow-growing seedlings, and whether they occur concurrently with hormetic effects. We tested the response of Lactuca sativa in complete dose-response experiments to six different toxicants at doses that did not decrease population mean and beyond. The tested toxicants were IAA, parthenin, HHCB, 4-tert-octylphenol, glyphosate, and pelargonic acid. Each experiment consisted of 14,400-16,800 seedlings, 12-14 concentrations, 24 replicates per concentration and 50 germinated seeds per replicate. We analyzed the commonness of selective low-dose effects and explored if toxic effects and hormetic stimulation among fast- and slow-growing individuals occurred at the same concentrations as they occur at the population level. Irrespective of the observed response pattern and toxicant, selective low-dose effects were found. Toxin effects among fast-growing individuals usually started at higher doses compared to the population mean, while the opposite was found among slow-growing individuals. Very low toxin exposures tended to homogenize plant populations due to selective effects, while higher, but still hormetic doses tended to heterogenize plant populations. Although the extent of observed size segregation varied with the specific toxin tested, we conclude that a dose-dependent alteration in size distribution of a plant population may generally apply for many toxin exposures. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Responses of some normal tissues to low doses of γ-radiation

    International Nuclear Information System (INIS)

    Withers, H.R.

    1975-01-01

    The response of four normal tissues to low doses of γ-radiation was measured in mice using three indirect methods. The survival curves for cells of the tissues studied (colon, jejunum, testis and haemoleucopoietic system) may be exponential over an uncertain dose range (from zero to between 100 to 230 rad), the slope being about one third of that in the high-dose region. Some of the uncertainties in the data probably reflect variations in age-density distribution. (author)

  5. Low-dose Ketamine Versus Morphine for Acute Pain In the ED: A Randomized Controlled Trial

    Science.gov (United States)

    2015-03-01

    pain [18,27,30,31]. Another unique aspect of this study was the use of the RASS score to capture the cognitive and behavioral effects of the study...pregnant or breast-feeding, history of chronic oxygen-dependent pulmonary disease, hepatic cirrhosis, or dialysis dependent, presence of intracranial...studies have evaluated low-dose ketamine as an adjunct to opioid therapy [29,30], as the sole agent without comparison[27], and in a retrospective

  6. The biological effects of low doses of ionizing radiation on adaptive possibilities of the organism

    International Nuclear Information System (INIS)

    Bulbuc, G.

    1997-01-01

    The study of adaptive possibilities and cancer risk in animals exposed at low doses of ionizing radiation was the object of the present work. The action of immunostimulating treatment on these processes was studied as well. In previously irradiated animals the diminution of adaptive possibilities and of the antitumoral resistance of the organism was observed. The stimulating action of Bufostimulin on these processes in irradiated animals was less pronounced than in unirradiated ones. (author)

  7. The treatment of autism with low-dose phenytoin: a case report.

    Science.gov (United States)

    Bird, Philip D

    2015-01-16

    The drug treatment of autism spectrum disorders is often poorly tolerated and has traditionally targeted associated conditions (such as inattention or irritability) that frequently coexist, with limited benefit for the core social deficits. Here, I describe the novel use of a low dose of the anti-epileptic phenytoin to enhance social functioning in a patient with an autism spectrum disorder. I present the case of a 19-year-old Caucasian man with autism spectrum disorder treated with stimulant medication since early childhood. He experienced long-standing difficulties in establishing and maintaining relationships and reading social cues, and was socially isolated. Within 10 minutes of a single sublingual low dose of phenytoin there was an immediate observable improvement in his eye contact and integration of both verbal and non-verbal communication. This enhanced social functioning associated with his adherence to the low-dose phenytoin therapy was maintained for over 18 months of follow-up. These clinical observations were supported by ratings using the Autism-Spectrum Quotient and the Depression, Anxiety and Stress Scales, recorded pre-treatment and after seven months on 5mg phenytoin. This case report provides the first potential evidence that a low dose of phenytoin, a widely used and well tolerated anti-epileptic medication, may be capable of modifying the core social cognitive deficits associated with autism spectrum disorders. While acknowledging this is a single case study, the lack of availability of safe and effective treatments to address the important core deficits associated with autism spectrum disorders makes this case noteworthy.

  8. Effects of low doses of A-bomb radiation on human lifespan

    International Nuclear Information System (INIS)

    Okumura, Y.; Mine, M.

    1997-01-01

    Among about 100,000 A-bomb survivors registered at Nagasaki University School of Medicine, male subjects exposed to 31 - 40 cGy showed significantly lower mortality from non-cancerous diseases than age-matched unexposed males. And the death rate for exposed male and female was smaller than that for unexposed. It was presented that the low doses of A-bomb radiation increased lifespan of A-bomb survivors. (author)

  9. Low-Dose Ketamine Infusion for Emergency Department Patients with Severe Pain.

    Science.gov (United States)

    Ahern, Terence L; Herring, Andrew A; Miller, Steve; Frazee, Bradley W

    2015-07-01

    Use of low-dose ketamine infusions in the emergency department (ED) has not previously been described, despite routine use in perioperative and other settings. Our hypothesis was that a low-dose ketamine bolus followed by continuous infusion would 1) provide clinically significant and sustained pain relief; 2) be well tolerated; and 3) be feasible in the ED. We prospectively administered 15 mg intravenous ketamine followed immediately by continuous ketamine infusion at 20 mg/h for 1 hour. Optional morphine (4 mg) was offered at 20, 40, and 60 minutes. Pain intensity, vitals signs, level of sedation, and adverse reactions were assessed for 120 minutes. A total of 38 patients were included with a median initial numerical rating scale (NRS) pain score of 9. At 10 minutes, the median reduction in pain score was 4, with 7 patients reporting a score of 0. At 60 and 120 minutes, 25 and 26 patients, respectively, reported clinically significant pain reduction (decrease NRS score > 3). Heart rate, blood pressure, respiratory rate, and oxygen saturation remained stable. Mild or moderate side effects including dizziness, fatigue, and headache were common. Patient satisfaction was high; 85% reported they would have this medication again for similar pain. A low-dose ketamine infusion protocol provided significant pain relief with mostly mild side effects and no severe adverse events. Wiley Periodicals, Inc.

  10. Low-dose CT of the paranasal sinuses. Minimizing X-ray exposure with spectral shaping

    Energy Technology Data Exchange (ETDEWEB)

    Wuest, Wolfgang [Friedrich-Alexander-University Erlangen-Nuremberg, Radiological Institute, Erlangen (Germany); Radiological Institute, Erlangen (Germany); May, Matthias; Saake, Marc; Brand, Michael; Uder, Michael; Lell, Michael [Friedrich-Alexander-University Erlangen-Nuremberg, Radiological Institute, Erlangen (Germany)

    2016-11-15

    Shaping the energy spectrum of the X-ray beam has been shown to be beneficial in low-dose CT. This study's aim was to investigate dose and image quality of tin filtration at 100 kV for pre-operative planning in low-dose paranasal CT imaging in a large patient cohort. In a prospective trial, 129 patients were included. 64 patients were randomly assigned to the study protocol (100 kV with additional tin filtration, 150mAs, 192 x 0.6-mm slice collimation) and 65 patients to the standard low-dose protocol (100 kV, 50mAs, 128 x 0.6-mm slice collimation). To assess the image quality, subjective parameters were evaluated using a five-point scale. This scale was applied on overall image quality and contour delineation of critical anatomical structures. All scans were of diagnostic image quality. Bony structures were of good diagnostic image quality in both groups, soft tissues were of sufficient diagnostic image quality in the study group because of a high level of noise. Radiation exposure was very low in both groups, but significantly lower in the study group (CTDI{sub vol} 1.2 mGy vs. 4.4 mGy, p < 0.001). Spectral optimization (tin filtration at 100 kV) allows for visualization of the paranasal sinus with sufficient image quality at a very low radiation exposure. (orig.)

  11. Learning from agriculture: understanding low-dose antimicrobials as drivers of resistome expansion

    Directory of Open Access Journals (Sweden)

    Yaqi eYou

    2014-06-01

    Full Text Available Antimicrobial resistance is a growing public health challenge worldwide, with agricultural use of antimicrobials being one major contributor to the emergence and dissemination of antimicrobial resistance. Globally, most antimicrobials are used in industrial food animal production, a major context for microbiomes encountering low-doses or subtherapeutic-levels of antimicrobial agents from all mechanistic classes. This modern practice exerts broad eco-evolutionary effects on the gut microbiome of food animals, which is subsequently transferred to animal waste. This waste contains complex constituents that are challenging to treat, including antimicrobial resistance determinants and low-dose antimicrobials. Unconfined storage or land deposition of a large volume of animal waste causes its wide contact with the environment and drives the expansion of the environmental resistome through mobilome facilitated horizontal genet transfer. The expanded environmental resistome, which encompasses both natural constituents and anthropogenic inputs, can persist under multiple stressors from agriculture and may re-enter humans, thus posing a public health risk to humans. For these reasons, this review focuses on agricultural antimicrobial use as a laboratory for understanding low-dose antimicrobials as drivers of resistome expansion, briefly summarizes current knowledge on this topic, highlights the importance of research specifically on environmental microbial ecosystems considering antimicrobial resistance as environmental pollution, and calls attention to the needs for longitudinal studies at the systems level.

  12. Effects of low-doses of Bacillus spp. from permafrost on differentiation of bone marrow cells.

    Science.gov (United States)

    Kalyonova, L F; Novikova, M A; Kostolomova, E G

    2015-01-01

    The effects of a new microorganism species (Bacillus spp., strain M3) isolated from permafrost specimens from Central Yakutia (Mamontova Mountain) on the bone marrow hemopoiesis were studied on laboratory mice. Analysis of the count and immunophenotype of bone marrow cells indicated that even in low doses (1000-5000 microbial cells) these microorganisms modulated hemopoiesis and lymphopoiesis activity. The percentage of early hemopoietic precursors (CD117(+)CD34(-)) increased, intensity of lymphocyte precursor proliferation and differentiation (CD25(+)CD44(-)) decreased, and the percentage of lymphocytes released from the bone marrow (CD25(+)CD44(+)) increased on day 21 after injection of the bacteria. These changes in activity of hemopoiesis were associated with changes in the level of regulatory T lymphocytes (reduced expression of TCRαβ) and were most likely compensatory. The possibility of modulating hemopoiesis activity in the bone marrow by low doses of one microorganism strain isolated from the permafrost could be useful for evaluating the effects of other low dose bacteria on the bone marrow hemopoiesis.

  13. Effect of low-dose ionizing radiation on luminous marine bacteria: radiation hormesis and toxicity

    International Nuclear Information System (INIS)

    Kudryasheva, N.S.; Rozhko, T.V.

    2015-01-01

    The paper summarizes studies of effects of alpha- and beta-emitting radionuclides (americium-241, uranium-235+238, and tritium) on marine microorganisms under conditions of chronic low-dose irradiation in aqueous media. Luminous marine bacteria were chosen as an example of these microorganisms; bioluminescent intensity was used as a tested physiological parameter. Non-linear dose-effect dependence was demonstrated. Three successive stages in the bioluminescent response to americium-241 and tritium were found: 1 – absence of effects (stress recognition), 2 – activation (adaptive response), and 3 – inhibition (suppression of physiological function, i.e. radiation toxicity). The effects were attributed to radiation hormesis phenomenon. Biological role of reactive oxygen species, secondary products of the radioactive decay, is discussed. The study suggests an approach to evaluation of non-toxic and toxic stages under conditions of chronic radioactive exposure. - Highlights: • Luminous bacteria demonstrate nonlinear dose-effect relation in radioactive solutions. • Response to low-dose radiation includes 3 stages: threshold, activation, inhibition. • ROS are responsible for low-dose effects of alpha-emitting radionuclides. • Luminous marine bacteria are a convenient tool to study radiation hormesis

  14. Comparative study of low dose 131I treatment in patients with Graves' disease

    International Nuclear Information System (INIS)

    Qin Lan; Shan Menglin; Wang Junqi

    2005-01-01

    Objective: To investigate the low dose 131 I therapy for Graves' disease we compared the results of 277 patients in our department with the report of Howarth D et al. Methods: 277 patients were classified as 45 Gy group and 77 Gy group according to the dose level. The results of these two groups were compared separately with results of 60 Gy group and 90 Gy group reported by Howarth D et al. Results: The euthyroidism rate and hypothyroidism rate among these four groups had no significant statistical difference after 6 months of 131 I therapy, but there were high significant statistical difference between our study and Howarth D research about euthyroidism rate and hypothyroidism rate 24 months later. Conclusion: The low dose 131 i management refered by Howarth D et al was an effective method for Graves' disease which could reduce or delay the incidence of hypothyroidism. Our study show that subsection on the foundation of this low dose procedure could further reduce the incidence of hypothyroidism and improve the euthyroidism rate. (authors)

  15. Can results from animal studies be used to estimate dose or low dose effects in humans

    International Nuclear Information System (INIS)

    Thomas, J.M.; Eberhardt, L.L.

    1981-01-01

    A method has been devised to extrapolate biological equilibrium levels between animal species and subsequently to humans. Our initial premise was based on the observation that radionuclide retention is normally a function of metabolism so that direct or indirect measures could be described by a power law based on body weights of test animal species. However, we found that such interspecies comparisons ought to be based on the coefficient of the power equation rather than on the exponential parameter. The method is illustrated using retention data obtained from five non-ruminant species (including humans) that were fed radionuclides with different properties. It appears that biological equilibrium level for radionuclides in man can be estimated using data from mice, rats, and dogs. The need to extrapolate low-dose effects data obtained from small animals (usually rodents) to humans is not unique to radiation dosimetry or radiation protection problems. Therefore, some quantitative problems connected with estimating low-dose effects from other disciplines have been reviewed, both because of the concern about effects induced by the radionuclide moiety of a radiopharmaceutical and those of the nonradioactive component. The possibility of extrapolating low-dose effects calculated from animal studies to human is discussed

  16. Metabolomics identifies a biological response to chronic low-dose natural uranium contamination in urine samples.

    Science.gov (United States)

    Grison, Stéphane; Favé, Gaëlle; Maillot, Matthieu; Manens, Line; Delissen, Olivia; Blanchardon, Eric; Banzet, Nathalie; Defoort, Catherine; Bott, Romain; Dublineau, Isabelle; Aigueperse, Jocelyne; Gourmelon, Patrick; Martin, Jean-Charles; Souidi, Maâmar

    2013-01-01

    Because uranium is a natural element present in the earth's crust, the population may be chronically exposed to low doses of it through drinking water. Additionally, the military and civil uses of uranium can also lead to environmental dispersion that can result in high or low doses of acute or chronic exposure. Recent experimental data suggest this might lead to relatively innocuous biological reactions. The aim of this study was to assess the biological changes in rats caused by ingestion of natural uranium in drinking water with a mean daily intake of 2.7 mg/kg for 9 months and to identify potential biomarkers related to such a contamination. Subsequently, we observed no pathology and standard clinical tests were unable to distinguish between treated and untreated animals. Conversely, LC-MS metabolomics identified urine as an appropriate biofluid for discriminating the experimental groups. Of the 1,376 features detected in urine, the most discriminant were metabolites involved in tryptophan, nicotinate, and nicotinamide metabolic pathways. In particular, N -methylnicotinamide, which was found at a level seven times higher in untreated than in contaminated rats, had the greatest discriminating power. These novel results establish a proof of principle for using metabolomics to address chronic low-dose uranium contamination. They open interesting perspectives for understanding the underlying biological mechanisms and designing a diagnostic test of exposure.

  17. Clinical investigation of 131I therapy combined with low-dose lithium carbonate for Graves disease

    International Nuclear Information System (INIS)

    Xu Haiqing; Wu Bian

    2006-01-01

    Objective: To investigate the clinical curative effects of 131 I therapy combined with low-dose lithium carbonate for Graves disease. Methods: Patients with Graves disease took lithium carbonate (250 mg, once per day) orally for 5 weeks. Then they were treated with 131 I (doses=3.15 MBq(80 uCi)/g, based on 60%-70% of the thyroid size). We kept track from 6 to 24 months (averaging 14 months) and classified the results into three: cured, improved or no effect. Results: After a single cycle of 131 I therapy combined with low-dose lithium carbonate, 106 patients with Graves disease were cured, 28 were improved and 8 saw no effects, respectively 74.6%, 19.7% and 5.6% among the 142 patients. We then treated 23 of them with another 131 I therapy (without lithium carbonate). 10 of such were cured (43.5%), 8 were improved (34.8%) and the other 5 saw no effects. Among all patients, hypothyroidism was observed from 25(17.6%), 6 months after the first 131 I therapy. Conclusions: Notable curative results were observed from 131 I therapy combined with low-dose lithium carbonate for Graves disease. Moreover, the dosage of 131 I was therefore decreased, which also lowered the toxicity response. (authors)

  18. Low-dose radioiodine given six-monthly in Graves' disease

    International Nuclear Information System (INIS)

    Hoskin, P.J.; McCready, V.R.; Harmer, C.L.; Spathis, G.S.; Cosgrove, D.O.

    1985-01-01

    Experience using low-dose radioiodine given six-monthly instead of yearly in hyperthyroid patients with Graves' disease is reported. One hundred and thirty-five patients have been treated over a three-year period with 74 MBq (2 mCi) doses of 131 I. |Thirty-eight|percent| were controlled with a single dose. Those patients requiring more than one dose were treated with a further 74 MBq (2 mCi) 131 I at six-monthly intervals until euthyroid. Using this approach, 46% were euthyroid one year after starting treatment, and 75% were euthyroid at two years. The incidence of hypothyroidism following treatment was 2.2% at one year, with a yearly incidence thereafter of 4-6%. Six-monthly scheduling of low-dose radioiodine in Graves' disease can reduce the time taken to become euthyroid, compared with conventional yearly low-dose treatments. Further follow up is required to confirm the present low incidence of hypothyroidism following treatment. (author)

  19. Parkinson’s Disease: Low-Dose Haloperidol Increases Dopamine Receptor Sensitivity and Clinical Response

    Directory of Open Access Journals (Sweden)

    Craig J. Hudson

    2014-01-01

    Full Text Available Background. It is known that ultra-low doses of haloperidol can cause dopamine supersensitivity of dopamine D2 receptors and related behaviour in animals. Objective. The objective was to determine whether a daily ultra-low dose of 40 micrograms of haloperidol could enhance the clinical action of levodopa in Parkinson’s disease patients. Method. While continuing their daily treatment with levodopa, 16 patients with Parkinson’s disease were followed weekly for six weeks. They received an add-on daily dose of 40 micrograms of haloperidol for the first two weeks only. The SPES/SCOPA scale (short scale for assessment of motor impairments and disabilities in Parkinson’s disease was administered before treatment and weekly throughout the trial. Results. The results showed a mean decrease in SPES/SCOPA scores after one week of the add-on treatment. Conclusion. SCOPA scores decreased after the addition of low-dose haloperidol to the standard daily levodopa dose. This finding is consistent with an increase in sensitivity of dopamine D2 receptors induced by haloperidol. Such treatment for Parkinson’s disease may possibly permit the levodopa dose to be reduced and, thus, delay the onset of levodopa side effects.

  20. Low-Dose Aspirin in Heart Failure Not Complicated by Atrial Fibrillation

    DEFF Research Database (Denmark)

    Madelaire, Christian; Gislason, Gunnar; Kristensen, Søren L

    2018-01-01

    OBJECTIVES: This study sought to assess safety and effectiveness of low-dose aspirin in heart failure (HF) not complicated by atrial fibrillation. BACKGROUND: Despite lack of evidence, low-dose aspirin is widely used in patients with HF and sinus rhythm with and without prior ischemic heart disease....... METHODS: The study included 12,277 patients with new-onset HF during 2007 to 2012 who had no history of atrial fibrillation. Of 5,450 patients using low-dose aspirin at baseline, 3,840 were propensity matched to non-aspirin users in a 1:1 ratio. Propensity-matched Cox models were calculated with respect...... to the primary composite outcome of all-cause mortality, myocardial infarction, and stroke and the secondary outcomes of bleeding and HF readmission. RESULTS: The composite outcome occurred in 1,554 (40.5%) patients in the aspirin group and 1,604 (41.8%) patients in the non-aspirin group. Aspirin use...