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Sample records for chronic low-dose uva

  1. 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)

  2. 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

  3. 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)

  4. Fractional carbon dioxide laser versus low-dose UVA-1 phototherapy for treatment of localized scleroderma: a clinical and immunohistochemical randomized controlled study.

    Science.gov (United States)

    Shalaby, S M; Bosseila, M; Fawzy, M M; Abdel Halim, D M; Sayed, S S; Allam, R S H M

    2016-11-01

    Morphea is a rare fibrosing skin disorder that occurs as a result of abnormal homogenized collagen synthesis. Fractional ablative laser resurfacing has been used effectively in scar treatment via abnormal collagen degradation and induction of healthy collagen synthesis. Therefore, fractional ablative laser can provide an effective modality in treatment of morphea. The study aimed at evaluating the efficacy of fractional carbon dioxide laser as a new modality for the treatment of localized scleroderma and to compare its results with the well-established method of UVA-1 phototherapy. Seventeen patients with plaque and linear morphea were included in this parallel intra-individual comparative randomized controlled clinical trial. Each with two comparable morphea lesions that were randomly assigned to either 30 sessions of low-dose (30 J/cm 2 ) UVA-1 phototherapy (340-400 nm) or 3 sessions of fractional CO 2 laser (10,600 nm-power 25 W). The response to therapy was then evaluated clinically and histopathologically via validated scoring systems. Immunohistochemical analysis of TGF-ß1 and MMP1 was done. Patient satisfaction was also assessed. Wilcoxon signed rank test for paired (matched) samples and Spearman rank correlation equation were used as indicated. Comparing the two groups, there was an obvious improvement with fractional CO 2 laser that was superior to that of low-dose UVA-1 phototherapy. Statistically, there was a significant difference in the clinical scores (p = 0.001), collagen homogenization scores (p = 0.012), and patient satisfaction scores (p = 0.001). In conclusion, fractional carbon dioxide laser is a promising treatment modality for cases of localized morphea, with proved efficacy of this treatment on clinical and histopathological levels.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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

  10. 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.

  11. Late effects of chronic low dose-rate γ-rays irradiation on mice

    International Nuclear Information System (INIS)

    Tanaka, Satoshi; Sasagawa, Sumiko; Ichinohe, Kazuaki; Matsumoto, Tsuneya; Otsu, Hiroshi; Sato, Fumiaki

    2002-01-01

    To evaluate late biological effects of chronic low dose-rate radiation, we are conducting two experiments. Experiment 1 - Late effects of chronic low dose-rate g-rays irradiation on SPF mice, using life-span and pathological changes as parameters. Continuous irradiation with g-rays for 400 days was performed using 137 Cs γ-rays at dose-rates of 20 mGy/day, 1 mGy/day and 0.05 mGy/day with accumulated doses equivalent to 8,000 mGy, 400 mGy and 20 mGy, respectively. All mice were kept until they died a natural death. As of 2002 March 31, 3,999 of the total 4,000 mice have died. Preliminary analyses of data show that 20 mGy/day suggested a shortened life span in both sexes. Partial results show that the most common lethal neoplasms in the pooled data of non-irradiated control and irradiated male mice, in order of frequency, were neoplasms of the lymphohematopoietic system, liver, and lung. In female mice, neoplasms of the lymphohematopoietic system, soft tissue, and endocrine system were common. Experiment 2 - Effects on the progeny of chronic low dose-rate g-ray irradiated SPF mice: pilot study, was started in 1999 and is currently in progress. (author)

  12. The effects of chronic, low doses of Ra-226 on cultured fish and human cells

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Xiaopei; Seymour, Colin; Mothersill, Carmel, E-mail: mothers@mcmaster.ca

    2016-07-15

    Purpose: To determine the chronic low-dose radiation effects caused by α-particle radiation from {sup 226}Ra over multiple cell generations in CHSE/F fish cells and HaCaT human cells. Methods: CHSE/F cells and HaCaT cells were cultured in medium containing {sup 226}Ra to deliver the chronic low-dose α-particle radiation. Clonogenic assay was used to test the clonogenic survival fractions of cells with or without being exposed to radiation from {sup 226}Ra. Results: The chronic low-dose radiation from {sup 226}Ra does have effects on the clonogenic survival of CHSE/F cells and HaCaT cells. When CHSE/F cells were cultured in {sup 226}Ra-medium over 9 passages for about 134 days, the clonogenic surviving fractions for cells irradiated at dose rates ranging from 0.00066 to 0.66 mGy/d were significantly lower than that of cells sham irradiated. For HaCaT cells grown in medium containing the same range of {sup 226}Ra activity, the clonogenic surviving fraction decreased at first and reached the lowest value at about 42 days (8 passages). After that, the clonogenic survival began to increase, and was significantly higher than that of control cells by the end of the experimental period. Conclusion: The chronic, low-dose high LET radiation from {sup 226}Ra can influence the clonogenic survival of irradiated cells. CHSE/F cells were sensitized by the radiation, and HaCaT cells were initially sensitized but later appeared to be adapted. The results could have implications for determining risk from chronic versus acute exposures to radium. - Highlights: • Cells were exposed to chronic low-dose α-radiation from {sup 226}Ra in medium with {sup 226}Ra. • The clonogenic survival of CHSE/F cells decreased when exposed to {sup 226}Ra for 134 days. • The clonogenic survival of HaCaT cells decreased at first and then increased. • The doubling time of both cells were not affected by this kind of radiation.

  13. Adaptation dynamics of laboratory populations of Drosophila Melanogaster to low dose chronic ionizing irradiation

    International Nuclear Information System (INIS)

    Zajnullin, V.G.; Yushkova, E.A.

    2008-01-01

    In genetically non-uniform populations D. melanogaster in conditions of a chronic irradiation in a doze 10-11 about sGy/generation dynamics parameters of populations was investigated. It is established, that number of individuals in irradiated populations is lower, than in control. It is revealed, that viability of populations undergone to a chronic irradiation depends on their genotype. The gradual increase in fruitfulness, viability of individuals and decrease in a level of lethal mutations in a number of generations after of an irradiation in low doses is caused by adaptable opportunities of populations. (authors)

  14. Genetic efficiency of low-dose chronic irradiation in mammals and fish

    International Nuclear Information System (INIS)

    Goncharova, R.; Ryabokon, N.; Smolich, I.; Slukvin, A.

    2001-01-01

    The problem of biological effects of low-dose chronic irradiation is central radiobiological problem and seems to be very important for human monitoring and risk assessment Since 1986 we are engaged in studying genetic effects of low-dose chronic irradiation in natural populations of small mammals (bank vole - Clethrioiiomys glareolus) inhabiting radiocontaminated monitoring sites, in laboratory hybrid mice CBA*C57BI/6 j exposed to chronic irradiation at radiocontaminated sites, as well as in pond carp (Cyprinus carpio) reared in fish farms in areas contaminated due to the Chernobyl accident. The mean ground depositions in monitoring sites were 8-2330 kBq/m 2 and the mean bottom depositions in ponds were 52-3235 Bq/kg for Cs 137. We used conventional cytogenetics and genetics tests [1-3] and the following approaches in studying on genetic effects of low-dose chronic irradiation: Radiation exposures from external γ- and internal α, β, γ-irradiation from incorporated radionuclides were estimated for each specimen tested. Regression analysis of dose-effect relationships based on comparison of individual genetic end-points with individual absorbed doses was carried out We observed statistically significant changes in the frequencies of genetic end-points, which have been studied in somatic and germ cells, as well as in embryos of irradiated mammals and fish. So, the frequencies of chromosome aberrations in bank vole populations had up to 7-fold increase in comparison with background and pre-accident levels. It is of great importance to emphasize high radio-sensitivity of fertilized eggs (zygotes) and pond carp, embryos produced by chronically irradiated parents. Regression analysis allowed to reveal dependence of the studied parameters' frequencies on radiation exposure namely on the concentrations of basic dose forming radionuclides, absorbed dose rate and whole body absorbed dose. In most cases, dose-effect relationships were better approximated by non

  15. 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

  16. Platelet-Rich Fibrin Lysate Can Ameliorate Dysfunction of Chronically UVA-Irradiated Human Dermal Fibroblasts.

    Science.gov (United States)

    Wirohadidjojo, Yohanes Widodo; Budiyanto, Arief; Soebono, Hardyanto

    2016-09-01

    To determine whether platelet-rich fibrin lysate (PRF-L) could restore the function of chronically ultraviolet-A (UVA)-irradiated human dermal fibroblasts (HDFs), we isolated and sub-cultured HDFs from six different human foreskins. HDFs were divided into two groups: those that received chronic UVA irradiation (total dosages of 10 J cm⁻²) and those that were not irradiated. We compared the proliferation rates, collagen deposition, and migration rates between the groups and between chronically UVA-irradiated HDFs in control and PRF-L-treated media. Our experiment showed that chronic UVA irradiation significantly decreased (p<0.05) the proliferation rates, migration rates, and collagen deposition of HDFs, compared to controls. Compared to control media, chronically UVA-irradiated HDFs in 50% PRF-L had significantly increased proliferation rates, migration rates, and collagen deposition (p<0.05), and the migration rates and collagen deposition of chronically UVA-irradiated HDFs in 50% PRF-L were equal to those of normal fibroblasts. Based on this experiment, we concluded that PRF-L is a good candidate material for treating UVA-induced photoaging of skin, although the best method for its clinical application remains to be determined.

  17. Central blood circulation in children at chronic combined low dose radiation and chemical action

    International Nuclear Information System (INIS)

    Arinchin, A.N.

    2000-01-01

    The state of central blood circulation and its hormonal regulation were studied in 1465 children living permanently under chronic low dose radiation and chemical action. Basic group consisted of 1093 children (579 boys and 514 girls) . 372 children (115 boys and 227 girls permanently living on 'clean' areas) were investigated in control group. Average age was 10,8 years old in basic group and 10,4 years old in the control group. Such parameters as arterial pressure, level of lead in blood and urine, adrenaline, noradrenaline and dophamine content in urine, thyroxine, iodothyronine, prostaglandins and cyclic AMP content in the blood serum has been controlled. Hypotensive states were determined to prevail in children living permanently under chronic low dose radiation and chemical action. The main pathogenic mechanism of this defeat is consider to be a reduction of the sympathoadrenal system activity combined with a decreasing of the thyroid system activity and of cyclic AMP level as well as predominance of prostaglandin depressive activity

  18. Influence of low doses chronic contamination on the progression of atheromatous pathology

    International Nuclear Information System (INIS)

    Le-Gallic, Clelia

    2015-01-01

    Large amounts of radionuclides were released in the environment after the Chernobyl (1986) or Fukushima-Daichii (2011) nuclear accidents, and mostly cesium 137. Populations living in contaminated territories are chronically exposed to radionuclides by ingestion of contaminated food. There is a real interrogation about the potential effects that could be induced following such ionizing exposure on physiological functions in the long term. Concerning the cardiovascular system, there is a correlation between the irradiation dose and the appearance of cardiovascular diseases. However, when we focused on post-accidental situations, with a low dose exposure, available data are not all in accordance, due to multifactorial aspect of these pathologies. Epidemiological results should be interpreted carefully. Thus, the aim of my thesis is to complete epidemiological studies about chronic internal? low dose exposure, using cesium 137, in an atheromatous context. Atherosclerosis and its consequences are known to be the main cause of mortality/morbidity in industrialized countries. Predisposed animals (ApoE-/- mice) were exposed to 137 Cs through the drinking water. The concentration range was 4 to 100 kBq.L -1 , to surround concentration found in contaminated territories around Chernobyl. Exposure times were 3, 6 or 9 months to follow atherosclerosis progression. After 3 months exposure, for the early stages, mice exposed to the highest dose presented an increase in some inflammatory cytokines, notably IFN-γ and VCAM-1, with an intimal-medial thickness increased compared to non-exposed animals. Moreover, at this time exposure, we noticed concomitant variation of gene expression of pro and anti-oxidative enzymes (p47, p67, GPx). These effects are only transient and do not persist over the time. Indeed, after 6 and 9 months exposure, atheromatous plaque observed in the aortic sinus, present more stability parameters than the control group (collagen), with also a decrease in pro

  19. Successful treatment of chronic recurrent multifocal osteomyelitis using low-dose radiotherapy. A case report

    International Nuclear Information System (INIS)

    Dietzel, Christian T.; Vordermark, Dirk; Schaefer, Christoph

    2017-01-01

    Chronic recurrent multifocal osteomyelitis (CRMO) is a rare autoinflammatory disease, which lacks an infectious genesis and predominantly involves the metaphysis of long bones. Common treatments range from nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids at first onset of disease, to immunosuppressive drugs and bisphosphonates in cases of insufficient remission. The therapeutic use of low-dose radiotherapy for CRMO constitutes a novelty. A 67-year-old female patient presented with radiologically proven CRMO affecting the right tibia/talus and no response to immunosuppressive therapy. Two treatment series of radiation therapy were applied with an interval of 6 weeks. Each series contained six fractions (three fractions per week) with single doses of 0.5 Gy, thus the total applied dose was 6 Gy. Ten months later, pain and symptoms of osteomyelitis had completely vanished. Radiotherapy seems to be an efficient and feasible complementary treatment option for conventional treatment refractory CRMO in adulthood. The application of low doses per fraction is justified by the inflammatory pathomechanism of disease. (orig.) [de

  20. Clinical effects of chronic low doses irradiation (11 years after Chernobyl accident)

    International Nuclear Information System (INIS)

    Romanenko, A.Y.; Bebeshko, V.G.

    1997-01-01

    Estimation of clinical effects of influence low doses of irradiation as the result of the Chernobyl accident on the human organism is presented in this report. The results of the investigations are concerning to changings in different organs and systems of inhabitants of the contamination territories and among clean-up workers. Increasing of morbidity of digestive and nervous systems is notified. Increase of thyroid cancer, chronic thyroidities and hypothyreouses is resisted in clean-up workers in dynamic observation. Highly morbidity of bronchopulmonal system and blood circulation system is revealed. High level of compensative and adaptive reactions of immune and hemopoietic systems is notified. Excesses of leukemias and lymphomas in inhabitants of the contamination territories is not demonstrated but tendency for increasing quantity cases of oncohematological diseases (leukemias, lymphomas, MDS) among clean-up workers IV-VII 1986 are absent. A dynamic of health state of children injured as a result of Chernobyl accident is characterized with continues negative tendencies. (author)

  1. The two strategies of plants to cope with chronic low dose irradiation

    International Nuclear Information System (INIS)

    Grodzinsky, D.M.

    2005-01-01

    Full text: The adaptive responses of plants to an increase in radioactivity of environment were established in radiobiological researches carried out in the Zone of the Chernobyl Nuclear Power Station. It has been shown that there are two types of adaptive strategies to the environment contaminated with radionuclides, namely ontogenetic and phylogenetic strategies. The ontogenetic adaptive strategy is attained by induction of DNA reparation. Increasing of the genetic variability in irradiated population performs the phylogenetic adaptive strategy. The mechanism of this strategy is associated with induction of genetic instability. Rise in the frequency of genetic recombination as well as heterozygosity is at the time essential components of phylogenetic adaptation. Ontogenetic and phylogenetic adaptation strategies are an important feature in coping of plants to the elevated chronic irradiation. Most likely plant cells as a stress signal into adaptive responses perceive the low doses of irradiation. (author)

  2. Effect of low dose radiation on expression of p16 gene in chronic myelogenous leukemia cells

    International Nuclear Information System (INIS)

    Zhang Longzhen; Ding Xin; Li Xiangyang; Cen Jiannong; Shen Hongjie; Chen Zixing

    2010-01-01

    Objective: To investigate the effect of low dose radiation on the expression on p16 gene in chronic myelogenous leukemia. Methods: Leukemic stem cells (LSCs) which expressed CD34 +, CD38 - and CD123 + were isolated from bone marrow cells obtained from twenty patients newly-diagnosedas chronic myeloid leukemia with EasySep TM magnet beads. Hematopoietic stem cells (HSCs) which expressed CD34 + and CD38 - were isolated from human cord blood cells obtained from twenty full-term deliveries with EasySep TM magnet beads as control. HSCs vs LSCs samples were further divided into three dose groups, including 0, 12.5 and 50 cGy, respectively. RT-PCR and real-time quantitative reverse transcription-polymerase chain reaction methods were used to detect mRNA expression of p16 gene in HSCs and LSCs after irradiation. Cells were harvested at different time for detection of cell cycle and apoptosis by flow cytometer. Results: p16 mRNA level in CML-LSCs was increased slightly at 12.5 cGy, and significantly increased at 50 cGy (Z=-3.39, P 0 /G 1 stagewas increased 48 h after 12.5 cGy irradiation, and 72 h post-irradiation with 50 cGy. The apoptosis rate of CML-LSCs was gradually raised after LDR, especially at 72 h post-irradiation of 50 cGy [(17.75±11.760% vs (6.13±4.71)%, Z=-2.37, P<0.01]. Conclusions: p16 gene transcription could be up-regulated by low dose radiation, which might provide a theoretical evidence for CML therapy and LDR in leukemic clinical application. (authors)

  3. Effect of Low-Dose Aspirin on Chronic Acid Reflux Esophagitis in Rats.

    Science.gov (United States)

    Masuda, Takahiro; Yano, Fumiaki; Omura, Nobuo; Tsuboi, Kazuto; Hoshino, Masato; Yamamoto, Se Ryung; Akimoto, Shunsuke; Kashiwagi, Hideyuki; Yanaga, Katsuhiko

    2018-01-01

    Clinical role of low-dose aspirin (LDA) in pathogenesis of gastroesophageal reflux disease is by far controversial. This can be attributed to the paucity of basic research detailing the mechanism of LDA-induced esophageal mucosal injury (EI) on underlying chronic acid reflux esophagitis (RE). The aim of this study was to clarify the effect of LDA on chronic RE in rats. Esophagitis was induced in 8-week-old male Wistar rats by ligating the border between forestomach and glandular portion with a 2-0 silk tie and covering the duodenum with a small piece of 18-Fr Nélaton catheter. Seventy-eight chronic RE rat models were divided into five treatment groups, consisting of orally administered vehicle (controls), and aspirin doses of 2, 5, 50 or 100 mg/kg once daily for 28 days. EI was assessed by gross area of macroscopic mucosal injury, severity grade of esophagitis and microscopic depth of infiltration by inflammatory cells. Area of esophagitis in animals with aspirin dose of 100 mg/kg/day showed a 36.5% increase compared with controls, although it failed to achieve statistical significance (p = 0.812). Additionally, the rate of severe EI was increased in animals with aspirin dose of 100 mg/kg/day as compared with controls (p aspirin (100 mg/kg/day) contributed in exacerbating preexisting EI. LDA (2 and 5 mg/kg/day), on the other hand, did not affect chronic RE in this model. LDA seems to be safe for use in patients with chronic RE.

  4. The use of low dose methotrexate in children with chronic anterior and intermediate uveitis.

    Science.gov (United States)

    Malik, A R; Pavesio, C

    2005-07-01

    To assess the efficacy of low dose methotrexate (MTX) therapy for children with chronic anterior and intermediate uveitis. A retrospective case review of 10 children who received MTX for chronic uveitis at a tertiary referral centre was performed. The following data were recorded for each patient: age, sex, race, duration of uveitis, primary diagnosis, anatomical localisation of uveitis, corticosteroid therapy, dose range of MTX, duration of MTX therapy, and side effects of MTX therapy. Several clinical parameters were evaluated to study the effect of MTX. These included visual acuity, anterior chamber inflammation, and topical and oral corticosteroid requirement. After MTX VA of 6/6 or better was present in 100% right eyes and 80% left eyes (p = 0.055 and p = 0.016, respectively). Anterior chamber inflammation decreased in 60% of children after MTX (p = 0.0168). The requirement of topical steroid decreased from a mean of 5.6 times a day before MTX to 1.5 times a day after MTX (p = 0.005). The dose of oral steroid decreased from a mean of 18 mg per day to 2.85 mg per day (p = 0.012). The most common adverse effect was nausea (20%). No patient required discontinuation of MTX because of side effects. MTX is effective and safe for chronic anterior and intermediate uveitis in children. An increase awareness of its efficacy is required among paediatricians and ophthalmologists to prevent sight threatening complication of chronic uveitis and its treatment with long term use of steroids.

  5. Chronic low-dose ultraviolet-induced mutagenesis in nucleotide excision repair-deficient cells.

    Science.gov (United States)

    Haruta, Nami; Kubota, Yoshino; Hishida, Takashi

    2012-09-01

    UV radiation induces two major types of DNA lesions, cyclobutane pyrimidine dimers (CPDs) and 6-4 pyrimidine-pyrimidine photoproducts, which are both primarily repaired by nucleotide excision repair (NER). Here, we investigated how chronic low-dose UV (CLUV)-induced mutagenesis occurs in rad14Δ NER-deficient yeast cells, which lack the yeast orthologue of human xeroderma pigmentosum A (XPA). The results show that rad14Δ cells have a marked increase in CLUV-induced mutations, most of which are C→T transitions in the template strand for transcription. Unexpectedly, many of the CLUV-induced C→T mutations in rad14Δ cells are dependent on translesion synthesis (TLS) DNA polymerase η, encoded by RAD30, despite its previously established role in error-free TLS. Furthermore, we demonstrate that deamination of cytosine-containing CPDs contributes to CLUV-induced mutagenesis. Taken together, these results uncover a novel role for Polη in the induction of C→T transitions through deamination of cytosine-containing CPDs in CLUV-exposed NER deficient cells. More generally, our data suggest that Polη can act as both an error-free and a mutagenic DNA polymerase, depending on whether the NER pathway is available to efficiently repair damaged templates.

  6. Low-dose computed tomography volumetry for subtyping chronic lung allograft dysfunction.

    Science.gov (United States)

    Saito, Tomohito; Horie, Miho; Sato, Masaaki; Nakajima, Daisuke; Shoushtarizadeh, Hassan; Binnie, Matthew; Azad, Sassan; Hwang, David M; Machuca, Tiago N; Waddell, Thomas K; Singer, Lianne G; Cypel, Marcelo; Liu, Mingyao; Paul, Narinder S; Keshavjee, Shaf

    2016-01-01

    The long-term success of lung transplantation is challenged by the development of chronic lung allograft dysfunction (CLAD) and its distinct subtypes of bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome (RAS). However, the current diagnostic criteria for CLAD subtypes rely on total lung capacity (TLC), which is not always measured during routine post-transplant assessment. Our aim was to investigate the utility of low-dose 3-dimensional computed tomography (CT) lung volumetry for differentiating RAS from BOS. This study was a retrospective evaluation of 63 patients who had developed CLAD after bilateral lung or heart‒lung transplantation between 2006 and 2011, including 44 BOS and 19 RAS cases. Median post-transplant follow-up was 65 months in BOS and 27 months in RAS. The median interval between baseline and the disease-onset time-point for CT volumetry was 11 months in both BOS and RAS. Chronologic changes and diagnostic accuracy of CT lung volume (measured as percent of baseline) were investigated. RAS showed a significant decrease in CT lung volume at disease onset compared with baseline (mean 3,916 ml vs 3,055 ml when excluding opacities, p volumetry is a useful tool to differentiate patients who develop RAS from those who develop BOS. Copyright © 2016 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

  7. Comparison of a low dose polyethylene glycol electrolyte solution with lactulose for treatment of chronic constipation.

    Science.gov (United States)

    Attar, A; Lémann, M; Ferguson, A; Halphen, M; Boutron, M C; Flourié, B; Alix, E; Salmeron, M; Guillemot, F; Chaussade, S; Ménard, A M; Moreau, J; Naudin, G; Barthet, M

    1999-02-01

    Polyethylene glycol (PEG) 3350 is a non-absorbable, non-metabolised osmotic agent used in lavage solutions for gut cleansing. To compare the efficacy of PEG and lactulose in chronic constipation. A total of 115 patients with chronic constipation entered a multicentre, randomised, comparative trial. They initially received two sachets containing either PEG (13 g/sachet) or lactulose (10 g/sachet) and were given an option to change the dose to one or three sachets/day, depending on response. Ninety nine patients completed the trial. After four weeks, patients in the PEG group (n=50) had a higher number of stools and a lower median daily score for straining at stool than patients in the lactulose group (n=49). Overall improvement was greater in the PEG group. Clinical tolerance was similar in the two groups, but flatus was less frequently reported in the PEG group. The mean number of liquid stools was higher in the PEG group but the difference was significant only for the first two weeks. There were no serious adverse events and no significant change in laboratory tests in either group. At the end of the study, the number of sachets used by the patients was 1.6 (0.7)/day in the PEG group and 2.1 (0.7)/day in the lactulose group. Sixty one patients completed a further two months open study of one to three sachets PEG daily; there was no loss of efficacy and no serious toxicity. Low dose PEG 3350 was more effective than lactulose and better tolerated.

  8. The metabolomic approach identifies a biological signature of low-dose chronic exposure to Cesium 137

    International Nuclear Information System (INIS)

    Grison, S.; Grandcolas, L.; Martin, J.C.

    2012-01-01

    Reports have described apparent biological effects of 137 Cs (the most persistent dispersed radionuclide) irradiation in people living in Chernobyl-contaminated territory. The sensitive analytical technology described here should now help assess the relation of this contamination to the observed effects. A rat model chronically exposed to 137 Cs through drinking water was developed to identify biomarkers of radiation-induced metabolic disorders, and the biological impact was evaluated by a metabolomic approach that allowed us to detect several hundred metabolites in biofluids and assess their association with disease states. After collection of plasma and urine from contaminated and non-contaminated rats at the end of the 9-months contamination period, analysis with a liquid chromatography coupled to mass spectrometry (LC-MS) system detected 742 features in urine and 1309 in plasma. Biostatistical discriminant analysis extracted a subset of 26 metabolite signals (2 urinary, 4 plasma non-polar, and 19 plasma polar metabolites) that in combination were able to predict from 68 up to 94% of the contaminated rats, depending on the prediction method used, with a misclassification rate as low as 5.3%. The difference in this metabolic score between the contaminated and non-contaminated rats was highly significant (P=0.019 after ANOVA cross-validation). In conclusion, our proof-of-principle study demonstrated for the first time the usefulness of a metabolomic approach for addressing biological effects of chronic low-dose contamination. We can conclude that a metabolomic signature discriminated 137 Cs-contaminated from control animals in our model. Further validation is nevertheless required together with full annotation of the metabolic indicators. (author)

  9. Successful treatment of chronic recurrent multifocal osteomyelitis using low-dose radiotherapy. A case report

    Energy Technology Data Exchange (ETDEWEB)

    Dietzel, Christian T.; Vordermark, Dirk [Klinikum der Martin-Luther-Universitaet Halle-Wittenberg, Universitaetslinik und Poliklinik fuer Strahlentherapie, Halle (Saale) (Germany); Schaefer, Christoph [Klinikum der Martin-Luther-Universitaet Halle-Wittenberg, Universitaetsklinik und Poliklinik fuer Innere Medizin II, Halle (Saale) (Germany)

    2017-03-15

    Chronic recurrent multifocal osteomyelitis (CRMO) is a rare autoinflammatory disease, which lacks an infectious genesis and predominantly involves the metaphysis of long bones. Common treatments range from nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids at first onset of disease, to immunosuppressive drugs and bisphosphonates in cases of insufficient remission. The therapeutic use of low-dose radiotherapy for CRMO constitutes a novelty. A 67-year-old female patient presented with radiologically proven CRMO affecting the right tibia/talus and no response to immunosuppressive therapy. Two treatment series of radiation therapy were applied with an interval of 6 weeks. Each series contained six fractions (three fractions per week) with single doses of 0.5 Gy, thus the total applied dose was 6 Gy. Ten months later, pain and symptoms of osteomyelitis had completely vanished. Radiotherapy seems to be an efficient and feasible complementary treatment option for conventional treatment refractory CRMO in adulthood. The application of low doses per fraction is justified by the inflammatory pathomechanism of disease. (orig.) [German] Die chronisch rekurrierende multifokale Osteomyelitis (CRMO) ist eine seltene autoimmunologische Erkrankung und befaellt vorzugsweise die Metaphysen der langen Roehrenknochen. Die Therapie umfasst nichtsteroidale Antirheumatika (NSAIDs) und Kortikosteroide bei Erstbefall und reicht bis hin zu Immunsuppressiva und Bisphosphonaten bei insuffizientem Ansprechen. Die Anwendung einer niedrigdosierten Radiatio stellt ein therapeutisches Novum dar. Eine 67-jaehrige Patientin stellte sich mit einem radiologisch gesicherten Befall im Sinne einer CRMO im Bereich des rechten Talus und der Tibia vor. Eine initiale Behandlung mit Immunsuppressiva verblieb erfolglos. Wir fuehrten zwei Bestrahlungsserien im Intervall von 6 Wochen durch. Jede Serie bestand aus 6 Fraktionen (3 Fraktionen/Woche), mit einer Einzeldosis von jeweils 0,5 Gy. Die

  10. Reproductive toxicity in rats after chronic oral exposure to low dose of depleted uranium

    International Nuclear Information System (INIS)

    Li Rong; Ai Guoping; Xu Hui; Su Yongping; Cheng Tianmin; Leng Yanbing

    2007-01-01

    Objective: To study the reproductive toxicity in rats induced by low dose of depleted uranium (DU). Methods: Male and female rats(F 0 generation) were exposed to DU in food at doses of 0, 0.4, 4 and 40 mg·kg -1 ·d -1 for 160 days, respectively. Then the activities of enzymes in testis and sexual hormone contents in serum were detected. Mature male rats were mated with female rats exposed to the same doses for 14 days. Pregnant rate and normal labor rate in F 0 rats were detected, as well as the survival rate and weight of F 1 rats within 21 d after birth. Results: No adverse effects of DU on fertility were evident at any dose in F 0 rats. Compared with control group, the rate of pregnancy, normal labor, survival of offspring birth and offspring nurture in F 1 generation of high-dose group reduced to 40.0%, 33.3%, 33.3%, and 33.3%, respectively. The sexual hormone contents in F 0 generation exposed increased, but those in Fl rats decreased significantly. The activities of lactate dehydrogenase-X (LDH-X) decreased in F 1 rats exposed to high-dose of DU, and those of sorbitol dehydrogenase (SDH), LDH and Na + -K + -ATPase decreased in F 1 rats exposed to DU. Conclusions: Reproduction function, growth and development of F 0 rats are not obviously affected after chronic oral exposure to DU, while the toxicity effects in F 1 generation was observed at any dose. (authors)

  11. Chronic ingestion of a low dose of caffeine induces tolerance to the performance benefits of caffeine.

    Science.gov (United States)

    Beaumont, Ross; Cordery, Philip; Funnell, Mark; Mears, Stephen; James, Lewis; Watson, Phillip

    2017-10-01

    This study examined effects of 4 weeks of caffeine supplementation on endurance performance. Eighteen low-habitual caffeine consumers (caffeine (1.5-3.0 mg · kg -1 day -1 ; titrated) or placebo for 28 days. Groups were matched for age, body mass, V̇O 2peak and W max (P > 0.05). Before supplementation, all participants completed one V̇O 2peak test, one practice trial and 2 experimental trials (acute 3 mg · kg -1 caffeine [precaf] and placebo [testpla]). During the supplementation period a second V̇O 2peak test was completed on day 21 before a final, acute 3 mg · kg -1 caffeine trial (postcaf) on day 29. Trials consisted of 60 min cycle exercise at 60% V̇O 2peak followed by a 30 min performance task. All participants produced more external work during the precaf trial than testpla, with increases in the caffeine (383.3 ± 75 kJ vs. 344.9 ± 80.3 kJ; Cohen's d effect size [ES] = 0.49; P = 0.001) and placebo (354.5 ± 55.2 kJ vs. 333.1 ± 56.4 kJ; ES = 0.38; P = 0.004) supplementation group, respectively. This performance benefit was no longer apparent after 4 weeks of caffeine supplementation (precaf: 383.3 ± 75.0 kJ vs. postcaf: 358.0 ± 89.8 kJ; ES = 0.31; P = 0.025), but was retained in the placebo group (precaf: 354.5 ± 55.2 kJ vs. postcaf: 351.8 ± 49.4 kJ; ES = 0.05; P > 0.05). Circulating caffeine, hormonal concentrations and substrate oxidation did not differ between groups (all P > 0.05). Chronic ingestion of a low dose of caffeine develops tolerance in low-caffeine consumers. Therefore, individuals with low-habitual intakes should refrain from chronic caffeine supplementation to maximise performance benefits from acute caffeine ingestion.

  12. 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.

  13. Low-dose radiation effects on the evolution of chronic dystrophical processes in cornea and clouding of crystalline lens

    International Nuclear Information System (INIS)

    Gajdaj, Yu.V.; Gajdaj, V.M.

    1993-01-01

    Low-dose radiation effects on the course of chronic dystrophical processes in cornea and the dynamics of crystalline lens clouding of involution age genesis are investigated in the patients participated in Chernobyl accident response. Examples of the concrete pathological cases are considered. It was stated that the above dose effects led to exacerbation of the chronic slack dystrophical processes in cornea and intensification of the development of cornea primary dystrophy. In a number of cases the intensification of development of crystalline lens clouding takes place resulted in the cataract for 2-3 years

  14. Seizures associated with low-dose tramadol for chronic pain treatment

    Science.gov (United States)

    Beyaz, Serbülent Gökhan; Sonbahar, Tuğba; Bayar, Fikret; Erdem, Ali Fuat

    2016-01-01

    The management of cancer pain still poses a major challenge for clinicians. Tramadol is a centrally acting synthetic opioid analgesic. Its well-known side effects include nausea, vomiting, and dizziness; seizures are a rare side effect. Some reports have found that tramadol triggers seizure activity at high doses, whereas a few preclinical studies have found that this seizure activity is not dose-related. We herein present a case involving a patient with laryngeal cancer who developed seizures while on low-dose oral tramadol. PMID:27212778

  15. Evaluation of chronic infectious interstitial pulmonary disease in children by low-dose CT-guided transthoracic lung biopsy

    Energy Technology Data Exchange (ETDEWEB)

    Heyer, Christoph M.; Lemburg, Stefan P.; Kagel, Thomas; Nicolas, Volkmar [Ruhr-University of Bochum, Institute of Diagnostic Radiology, Interventional Radiology and Nuclear Medicine, BG Clinics Bergmannsheil, Bochum (Germany); Mueller, Klaus-Michael [Ruhr-University of Bochum, Institute of Pathology, BG Clinics Bergmannsheil, Bochum (Germany); Nuesslein, Thomas G.; Rieger, Christian H.L. [Ruhr-University of Bochum, Pediatric Hospital, Bochum (Germany)

    2005-07-01

    Children with chronic infectious interstitial lung disease often have to undergo open lung biopsy to establish a final diagnosis. Open lung biopsy is an invasive procedure with major potential complications. Transthoracic lung biopsy (TLB) guided by computed tomography (CT) is a less-invasive well-established procedure in adults. Detailing the role of low-dose CT-guided TLB in the enhanced diagnosis of chronic lung diseases related to infection in children. A group of 11 children (age 8 months to 16 years) underwent CT-guided TLB with a 20-gauge biopsy device. All investigations were done under general anaesthesia on a multidetector CT scanner (SOMATOM Volume Zoom, Siemens, Erlangen, Germany) using a low-dose protocol (single slices, 120 kV, 20 mAs). Specimens were processed by histopathological, bacteriological, and virological techniques. All biopsies were performed without major complications; one child developed a small pneumothorax that resolved spontaneously. A diagnosis could be obtained in 10 of the 11 patients. Biopsy specimens revealed chronic interstitial alveolitis in ten patients. In five patients Chlamydia pneumoniae PCR was positive, in three Mycoplasma pneumoniae PCR was positive, and in two Cytomegalovirus PCR was positive. The average effective dose was 0.83 mSv. Low-dose CT-guided TLB can be a helpful tool in investigating chronic infectious inflammatory processes in children with minimal radiation exposure. It should be considered prior to any open surgical procedure performed for biopsy alone. In our patient group no significant complication occurred. A disadvantage of the method is that it does not allow smaller airways and vessels to be assessed. (orig.)

  16. The Safety and Efficacy of Low-Dose Naltrexone in the Management of Chronic Pain and Inflammation in Multiple Sclerosis, Fibromyalgia, Crohn's Disease, and Other Chronic Pain Disorders.

    Science.gov (United States)

    Patten, Denise K; Schultz, Bob G; Berlau, Daniel J

    2018-03-01

    Chronic inflammatory diseases are complex to treat and have an impact on a large number of patients. Due to the difficulty of treating these diseases and the great impact on quality of life, patients often seek off-label, complimentary, or alternative medicines to gain relief from symptoms. Low-dose naltrexone has been used off-label for treatment of pain and inflammation in multiple sclerosis, Crohn's disease, fibromyalgia, and other diseases. Naltrexone is a mu-opioid receptor antagonist indicated by the U.S. Food and Drug Administration for opioid and alcohol dependence. It is hypothesized that lower than standard doses of naltrexone inhibit cellular proliferation of T and B cells and block Toll-like receptor 4, resulting in an analgesic and antiinflammatory effect. It is the purpose of this review to examine the evidence of the safety, tolerability, and efficacy of low-dose naltrexone for use in chronic pain and inflammatory conditions. Currently, evidence supports the safety and tolerability of low-dose naltrexone in multiple sclerosis, fibromyalgia, and Crohn's disease. Fewer studies support the efficacy of low-dose naltrexone, with most of these focusing on subjective measures such as quality of life or self-reported pain. These studies do demonstrate that low-dose naltrexone has subjective benefits over placebo, but evidence for more objective measures is limited. However, further randomized controlled trials are needed to determine the efficacy of low-dose naltrexone due to insufficient evidence supporting its use in these disease states. This review provides practitioners with the extent of low-dose naltrexone evidence so that they can be cognizant of situations where it may not be the most appropriate therapy. © 2018 Pharmacotherapy Publications, Inc.

  17. Selective brain responses to acute and chronic low-dose X-ray irradiation in males and females

    International Nuclear Information System (INIS)

    Silasi, Greg; Diaz-Heijtz, Rochellys; Besplug, Jill; Rodriguez-Juarez, Rocio; Titov, Viktor; Kolb, Bryan; Kovalchuk, Olga

    2004-01-01

    Radiation exposure is known to have profound effects on the brain, leading to precursor cell dysfunction and debilitating cognitive declines [Nat. Med. 8 (2002) 955]. Although a plethora of data exist on the effects of high radiation doses, the effects of low-dose irradiation, such as ones received during repetitive diagnostic and therapeutic exposures, are still under-investigated [Am. J. Otolaryngol. 23 (2002) 215; Proc. Natl. Acad. Sci. USA 97 (2000) 889; Curr. Opin. Neurol. 16 (2003) 129]. Furthermore, most studies of the biological effects of ionizing radiation have been performed using a single acute dose, while clinically and environmentally relevant exposures occur predominantly under chronic/repetitive conditions. Here, we have used a mouse model to compare the effects of chronic/repetitive and acute low-dose radiation (LDR) exposure (0.5 Gy) to ionizing radiation on the brain in vivo. We examined the LDR effects on p42/44 MAPK (ERK1/ERK2), CaMKII, and AKT signaling-the interconnected pathways that have been previously shown to be crucial for neuronal survival upon irradiation. We report perturbations in ERK1/2, AKT, and CREB upon acute and chronic/repetitive low-dose exposure in the hippocampus and frontal cortex of mice. These studies were paralleled by the analysis of radiation effects on neurogenesis and cellular proliferation. Repetitive exposure had a much more pronounced effect on cellular signaling and neurogenesis than acute exposure. These results suggest that studies of single acute exposures might be limited in terms of their predictive value. We also present the first evidence of sex differences in radiation-induced signaling in the hippocampus and frontal cortex. We show the role of estrogens in brain radiation responses and discuss the implications of the observed changes

  18. Effects of Low Dose Chronic Radiation and Heavy Metals on Plants and Their Fungal and Virus Infections

    Directory of Open Access Journals (Sweden)

    A Dmitriev

    2009-06-01

    Full Text Available The effects of low dose chronic radiation on plant disease resistance and fungal and virus infections have been studied. The results obtained in the 10-km Chernobyl zone demonstrated a decrease in plant disease resistance and appearance of a "new" population of stem rust agents of cereal with a high frequency of more virulent clones. Radionuclide contamination and heavy metals lead to wider virus spread and a higher diversity of virus species. The Chernobyl zone is a territory of enhanced risk and potential threats for the environment. A special type of monitoring of microevolution processes in plant pathogens should provide better understanding of how serious these potential threats are.

  19. Chronic use of low-dose aspirin is not associated with lower bone mineral density in the general population.

    Science.gov (United States)

    Bonten, T N; de Mutsert, R; Rosendaal, F R; Jukema, J W; van der Bom, J G; de Jongh, R T; den Heijer, M

    2017-10-01

    Low-dose aspirin is the cornerstone of secondary prevention of cardiovascular disease. Previous studies suggested that the use of aspirin is associated with an increased fracture risk. However, there is uncertainty whether this is due to an effect of aspirin on bone mineral density (BMD). Between 2008 and 2012, information on medication use and dual X-ray absorptiometry measured vertebral and femoral BMD of 916 participants was collected in the Netherland Epidemiology of Obesity study. The cross-sectional association between chronic low-dose aspirin use and BMD was estimated using linear regression, controlling for demography, body composition, comorbidity and other medication use which could affect BMD. A subgroup analysis in postmenopausal women (n=329) was conducted. After full adjustment, there was no difference between aspirin users and non-users for vertebral BMD (adjusted mean difference: 0.036 (95% CI -0.027 to 0.100) g/cm 2 ) and femoral BMD (adjusted mean difference: 0.001 (-0.067 to 0.069) g/cm 2 ). Also in the subgroup of postmenopausal women, aspirin use was not associated with lower vertebral (adjusted mean difference: 0.069 (-0.046 to 0.184) g/cm 2 ) or femoral BMD (adjusted mean difference: -0.055 (-0.139;0.029) g/cm 2 ). Chronic use of low-dose aspirin is not associated with lower BMD in the general population. The increased risk of fractures observed in aspirin users in previous studies is therefore more likely to be the result of common causes of aspirin use and fractures, but not of direct effects of aspirin on BMD. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  20. A chronic low dose of Δ9-tetrahydrocannabinol (THC) restores cognitive function in old mice.

    Science.gov (United States)

    Bilkei-Gorzo, Andras; Albayram, Onder; Draffehn, Astrid; Michel, Kerstin; Piyanova, Anastasia; Oppenheimer, Hannah; Dvir-Ginzberg, Mona; Rácz, Ildiko; Ulas, Thomas; Imbeault, Sophie; Bab, Itai; Schultze, Joachim L; Zimmer, Andreas

    2017-06-01

    The balance between detrimental, pro-aging, often stochastic processes and counteracting homeostatic mechanisms largely determines the progression of aging. There is substantial evidence suggesting that the endocannabinoid system (ECS) is part of the latter system because it modulates the physiological processes underlying aging. The activity of the ECS declines during aging, as CB1 receptor expression and coupling to G proteins are reduced in the brain tissues of older animals and the levels of the major endocannabinoid 2-arachidonoylglycerol (2-AG) are lower. However, a direct link between endocannabinoid tone and aging symptoms has not been demonstrated. Here we show that a low dose of Δ 9 -tetrahydrocannabinol (THC) reversed the age-related decline in cognitive performance of mice aged 12 and 18 months. This behavioral effect was accompanied by enhanced expression of synaptic marker proteins and increased hippocampal spine density. THC treatment restored hippocampal gene transcription patterns such that the expression profiles of THC-treated mice aged 12 months closely resembled those of THC-free animals aged 2 months. The transcriptional effects of THC were critically dependent on glutamatergic CB1 receptors and histone acetylation, as their inhibition blocked the beneficial effects of THC. Thus, restoration of CB1 signaling in old individuals could be an effective strategy to treat age-related cognitive impairments.

  1. Comparison of a low dose polyethylene glycol electrolyte solution with lactulose for treatment of chronic constipation

    OpenAIRE

    Attar, A; Lemann, M; Ferguson, A; Halphen, M; Boutron, M; Flourie, B; Alix, E; Salmeron, M; Guillemot, F; Chaussade, S; Menard, A; Moreau, J; Naudin, G; Barthet, M

    1999-01-01

    Background—Polyethylene glycol (PEG) 3350 is a non-absorbable, non-metabolised osmotic agent used in lavage solutions for gut cleansing. 
Aims—To compare the efficacy of PEG and lactulose in chronic constipation. 
Methods—A total of 115 patients with chronic constipation entered a multicentre, randomised, comparative trial. They initially received two sachets containing either PEG (13 g/sachet) or lactulose (10 g/sachet) and were given an option to change the dose to one ...

  2. Cancer and non-cancer brain and eye effects of chronic low-dose ionizing radiation exposure

    International Nuclear Information System (INIS)

    Picano, Eugenio; Vano, Eliseo; Domenici, Luciano; Bottai, Matteo; Thierry-Chef, Isabelle

    2012-01-01

    According to a fundamental law of radiobiology (“Law of Bergonié and Tribondeau”, 1906), the brain is a paradigm of a highly differentiated organ with low mitotic activity, and is thus radio-resistant. This assumption has been challenged by recent evidence discussed in the present review. Ionizing radiation is an established environmental cause of brain cancer. Although direct evidence is lacking in contemporary fluoroscopy due to obvious sample size limitation, limited follow-up time and lack of focused research, anecdotal reports of clusters have appeared in the literature, raising the suspicion that brain cancer may be a professional disease of interventional cardiologists. In addition, although terminally differentiated neurons have reduced or mild proliferative capacity, and are therefore not regarded as critical radiation targets, adult neurogenesis occurs in the dentate gyrus of the hippocampus and the olfactory bulb, and is important for mood, learning/memory and normal olfactory function, whose impairment is a recognized early biomarker of neurodegenerative diseases. The head doses involved in radiotherapy are high, usually above 2 Sv, whereas the low-dose range of professional exposure typically involves lifetime cumulative whole-body exposure in the low-dose range of < 200 mSv, but with head exposure which may (in absence of protection) arrive at a head equivalent dose of 1 to 3 Sv after a professional lifetime (corresponding to a brain equivalent dose around 500 mSv). At this point, a systematic assessment of brain (cancer and non-cancer) effects of chronic low-dose radiation exposure in interventional cardiologists and staff is needed

  3. Low dose chronic Schistosoma mansoni infection increases susceptibility to Mycobacterium bovis BCG infection in mice

    DEFF Research Database (Denmark)

    Elias, D; Akuffo, H; Thors, C

    2005-01-01

    The incidence of mycobacterial diseases is high and the efficacy of Bacillus Calmette Guerin (BCG) is low in most areas of the world where chronic worm infections are common. However, if and how concurrent worm infections could affect immunity to mycobacterial infections has not been elucidated. ...

  4. Blood pressure response to conventional and low-dose enalapril in chronic renal failure

    DEFF Research Database (Denmark)

    Elung-Jensen, Thomas; Heisterberg, Jens; Kamper, Anne-Lise

    2003-01-01

    AIMS: In chronic renal failure, the clearance of most ACE inhibitors including enalapril is reduced. Hence, with conventional dosage, plasma enalaprilat may be markedly elevated. It is unclear whether this excess of drug exposure affords an improved control of blood pressure. The aim of the present...... study was to evaluate short-term blood pressure response to two different plasma levels of enalaprilat. METHODS: As part of an open, randomized, controlled trial of the effect of high and low dosage of enalapril on the progression of renal failure, short-term blood pressure response was evaluated. Data...... potassium concentrations at day 90 and patients in the low group experienced a slight increase in GFR. CONCLUSIONS: In moderate to severe chronic renal insufficiency the same degree of blood pressure control was achieved on low as well as moderate daily doses of enalapril. This was irrespective...

  5. Blood pressure response to conventional and low-dose enalapril in chronic renal failure

    DEFF Research Database (Denmark)

    Elung-Jensen, Thomas; Heisterberg, Jens; Kamper, Anne-Lise

    2003-01-01

    AIMS: In chronic renal failure, the clearance of most ACE inhibitors including enalapril is reduced. Hence, with conventional dosage, plasma enalaprilat may be markedly elevated. It is unclear whether this excess of drug exposure affords an improved control of blood pressure. The aim of the present...... study was to evaluate short-term blood pressure response to two different plasma levels of enalaprilat. METHODS: As part of an open, randomized, controlled trial of the effect of high and low dosage of enalapril on the progression of renal failure, short-term blood pressure response was evaluated. Data...

  6. MDMA-assisted psychotherapy using low doses in a small sample of women with chronic posttraumatic stress disorder.

    Science.gov (United States)

    Bouso, José Carlos; Doblin, Rick; Farré, Magí; Alcázar, Miguel Angel; Gómez-Jarabo, Gregorio

    2008-09-01

    The purpose of this study was to investigate the safety of different doses of MDMA-assisted psychotherapy administered in a psychotherapeutic setting to women with chronic PTSD secondary to a sexual assault, and also to obtain preliminary data regarding efficacy. Although this study was originally planned to include 29 subjects, political pressures led to the closing of the study before it could be finished, at which time only six subjects had been treated. Preliminary results from those six subjects are presented here. We found that low doses of MDMA (between 50 and 75 mg) were both psychologically and physiologically safe for all the subjects. Future studies in larger samples and using larger doses are needed in order to further clarify the safety and efficacy of MDMA in the clinical setting in subjects with PTSD.

  7. Low-dose intravenous ketamine for postcardiac surgery pain: Effect on opioid consumption and the incidence of chronic pain.

    Science.gov (United States)

    Cogan, Jennifer; Lalumière, Geneviève; Vargas-Schaffer, Grisell; Deschamps, Alain; Yegin, Zeynep

    2017-01-01

    Recent meta-analyses have concluded that low-dose intravenous ketamine infusions (LDKIs) during the postoperative period may help to decrease acute and chronic postoperative pain after major surgery. This study aims to evaluate the level of pain at least 3 months after surgery for patients treated with a postoperative LDKI versus patients who were not treated with a postoperative LDKI. Administrative and Ethics Board approval were obtained for this study. We performed a retrospective chart review for all patients receiving LDKI, and equal number of age-, sex-, and surgery-matched patients who did not receive LDKI. Low-dose ketamine was prepared using 100 mg of ketamine in 100 ml of normal saline and run between 50 and 200 mcg/kg/h. We reviewed 115 patients with LDKI and 115 without LDKI. The average age was 63.1 years, 73% of the patients were men and sex was evenly distributed between LDKI and non-LDKI. The average duration of the ketamine infusions was 26.8 h with the average dose being 169.9 mg. At an average of 9 months after surgery, 42% of the ketamine group and 38% of the nonketamine group stated that they had had pain on discharge. Of these patients, 30% of the ketamine group and 26% of the nonketamine group still had pain at the time of the phone call. Women in both groups had more acute and chronic pain than men. These results show that LDKI does not promote a decrease in long-term postoperative pain.

  8. Augmentation of natural cytotoxicity by chronic low-dose ionizing radiation in murine natural killer cells primed by IL-2

    International Nuclear Information System (INIS)

    Sonn, Chung-Hee; Choi, Jong-Rip; Kim, Tae-Jin

    2012-01-01

    The possible beneficial effects of chronic low-dose irradiation (LDR) and its mechanism of action in a variety of pathophysiological processes such as cancer are a subject of intense investigation. While animal studies involving long-term exposure to LDR have yielded encouraging results, the influence of LDR at the cellular level has been less well defined. We reasoned that since natural killer (NK) cells constitute an early responder to exogenous stress, NK cells may reveal sentinel alterations in function upon exposure to LDR. When purified NK cells received LDR at 4.2 mGy/h for a total of 0.2 Gy in vitro, no significant difference in cell viability was observed. Likewise, no functional changes were detected in LDR-exposed NK cells, demonstrating that LDR alone was insufficient to generate changes at the cellular level. Nonetheless, significant augmentation of cytotoxic, but not proliferative, function was detected when NK cells were stimulated with low-dose IL-2 prior to irradiation. This enhancement of NK cytotoxicity was not due to alterations in NK-activating receptors, NK1.1, NKG2D, CD69 and 2B4, or changes in the rate of early or late apoptosis. Therefore, LDR, in the presence of suboptimal cytokine levels, can facilitate anti-tumor cytotoxicity of NK cells without influencing cellular proliferation or apoptosis. Whether these results translate to in vivo consequences remains to be seen; however, our data provide initial evidence that exposure to LDR can lead to subtle immune-enhancing effects on NK cells and may explain, in part, the functional basis underlying, diverse beneficial effects seen in the animals chronically exposed to LDR. (author)

  9. Morbidity rate of nervous system among medical personnel occupationally exposed to chronic low dose irradiation

    International Nuclear Information System (INIS)

    Jonkova, A.

    1987-01-01

    The morbidity rate of the nervous system among 1190 subjects, medical personnel, working with sources and environment of ionizing radiation was studied by the personal analysis of the diseases, written down in the personal out-patient department cards as well as of a control group of 870 medical workers of various other specialities. The morbidity rate of the nervous system among the medical personnel, exposed to chronic occupational radiation effect, was established not to be higher than that of the other medical workers - 38.0 and 40.3% respectively. Neuroses and peripheral nervous diseases have the greatest relative share in the structure of morbidity rate of the nervous system in both groups examined, with no statistical significance in the differences of the indices. The significantly higher incidence of autonome dystonias, established among the personnel from the X-ray departments and consulting rooms could be discussed in connection with the great relative share of the subjects from that group with a length of service over 15 years and had received the possible maximum cumulative equivalent doses. 3 tabs., 21 refs

  10. The Management of Patients with Chronic Subdural Hematoma Treated with Low-Dose Acetylsalicylic Acid: An International Survey of Practice.

    Science.gov (United States)

    Soleman, Jehuda; Kamenova, Maria; Guzman, Raphael; Mariani, Luigi

    2017-11-01

    The aim of this international survey was to investigate the current management of patients undergoing surgery for chronic subdural hematoma (cSDH) treated with low-dose acetylsalicylic acid (ASA). We administered a survey via e-mail to neurosurgeons with questions relating to the surgical treatment of cSDH, emphasizing their practices with patients treated with low-dose ASA. We received 157 responses, with a response rate of 22.4%. Almost 80% of the responders discontinue ASA treatment at least 5 days before surgery and 80.7% resume treatment after 5 days or more, and 27.6% discontinue treatment for at least 30 days. The main factor influencing ASA resumption time is the indication for ASA (54.5%), and postoperative imaging is concluded in 71.7%, Postoperative thrombosis prophylaxis is administered by 60% of the responders, and 50% apply it 24 hours after surgery. Almost 95% of the responders believe that better evidence is needed for the management of patients with cSDH treated with ASA. Guidelines for these patients exist in only 24.3% of the institutes. Most neurosurgeons discontinue ASA treatment for at least 7 days in the perioperative period of surgical evacuation of cSDH, even though recent studies show that early ASA resumption might be safe. Thrombosis prophylaxis is administered by only 60%, even though patients with cSDH are at high risk of developing thromboembolic complications. Better evidence and guidelines are warranted because the incidence of patients with cSDH under the treatment of ASA is increasing. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. 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)

  12. 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)

  13. Chronic low-dose γ-irradiation of Drosophila melanogaster larvae induces gene expression changes and enhances locomotive behavior

    International Nuclear Information System (INIS)

    Kim, Cha Soon; Lee, Byung Sub; Lee, In Kyung; Yang, Kwang Hee; Kim, Ji-Young; Nam, Seon Young; Seong, Ki Moon

    2015-01-01

    Although radiation effects have been extensively studied, the biological effects of low-dose radiation (LDR) are controversial. This study investigates LDR-induced alterations in locomotive behavior and gene expression profiles of Drosophila melanogaster. We measured locomotive behavior using larval pupation height and the rapid iterative negative geotaxis (RING) assay after exposure to 0.1 Gy γ-radiation (dose rate of 16.7 mGy/h). We also observed chronic LDR effects on development (pupation and eclosion rates) and longevity (life span). To identify chronic LDR effects on gene expression, we performed whole-genome expression analysis using gene-expression microarrays, and confirmed the results using quantitative real-time PCR. The pupation height of the LDR-treated group at the first larval instar was significantly higher (∼2-fold increase in PHI value, P < 0.05). The locomotive behavior of LDR-treated male flies (∼3 − 5 weeks of age) was significantly increased by 7.7%, 29% and 138%, respectively (P < 0.01), but pupation and eclosion rates and life spans were not significantly altered. Genome-wide expression analysis identified 344 genes that were differentially expressed in irradiated larvae compared with in control larvae. We identified several genes belonging to larval behavior functional groups such as locomotion (1.1%), oxidation reduction (8.0%), and genes involved in conventional functional groups modulated by irradiation such as defense response (4.9%), and sensory and perception (2.5%). Four candidate genes were confirmed as differentially expressed genes in irradiated larvae using qRT-PCR (>2-fold change). These data suggest that LDR stimulates locomotion-related genes, and these genes can be used as potential markers for LDR. (author)

  14. Chronic dietary exposure to a low-dose mixture of genistein and vinclozolin modifies the reproductive axis, testis transcriptome, and fertility.

    Science.gov (United States)

    Eustache, Florence; Mondon, Françoise; Canivenc-Lavier, Marie Chantal; Lesaffre, Corinne; Fulla, Yvonne; Berges, Raymond; Cravedi, Jean Pierre; Vaiman, Daniel; Auger, Jacques

    2009-08-01

    The reproductive consequences and mechanisms of action of chronic exposure to low-dose endocrine disruptors are poorly understood. We assessed the effects of a continuous, low-dose exposure to a phytoestrogen (genistein) and/or an antiandrogenic food contaminant (vinclozolin) on the male reproductive tract and fertility. Male rats were exposed by gavage to genistein and vinclozolin from conception to adulthood, alone or in combination, at low doses (1 mg/kg/day) or higher doses (10 and 30 mg/kg/day). We studied a number of standard reproductive toxicology end points and also assessed testicular mRNA expression profiles using long-oligonucleotide microarrays. The low-dose mixture and high-dose vinclozolin produced the most significant alterations in adults: decreased sperm counts, reduced sperm motion parameters, decreased litter sizes, and increased post implantation loss. Testicular mRNA expression profiles for these exposure conditions were strongly correlated. Functional clustering indicated that many of the genes induced belong to the "neuroactive ligand-receptor interactions" family encompassing several hormonally related actors (e.g., follicle-stimulating hormone and its receptor). All exposure conditions decreased the levels of mRNAs involved in ribosome function, indicating probable decreased protein production. Our study shows that chronic exposure to a mixture of a dose of a phytoestrogen equivalent to that in the human diet and a low dose-albeit not environmental-of a common anti-androgenic food contaminant may seriously affect the male reproductive tract and fertility.

  15. Randomized study on hydroxyurea alone versus hydroxyurea combined with low-dose interferon-alpha 2b for chronic myeloid leukemia

    NARCIS (Netherlands)

    Kluin-Nelemans, JC; Delannoy, A; Louwagie, A; Le Cessie, S; Hermans, J; van der Burgh, JF; Hagemeijer, AM; Van den Berghe, H

    1998-01-01

    Interferon-alpha (IFN-alpha) is considered the standard therapy for chronic myeloid leukemia (CML) patients not suitable for allogeneic stem cell transplantation. From 1987 through 1992, 195 patients in the Benelux with recent untreated CML were randomized between low-dose IFN-alpha 2b (3 MIU, 5

  16. Chronic low-dose-rate ionising radiation affects the hippocampal phosphoproteome in the ApoE-/- Alzheimer's mouse model

    DEFF Research Database (Denmark)

    Kempf, S. J.; Janik, Dirk; Barjaktarovic, Zarko

    2016-01-01

    Accruing data indicate that radiation-induced consequences resemble pathologies of neurodegenerative diseases such as Alzheimer's. The aim of this study was to elucidate the effect on hippocampus of chronic low-dose-rate radiation exposure (1 mGy/day or 20 mGy/day) given over 300 days with cumula...

  17. Treatment of chronic hemodialysis patients with low-dose fenofibrate effectively reduces plasma lipids and affects plasma redox status

    Directory of Open Access Journals (Sweden)

    Makówka Agnieszka

    2012-07-01

    Full Text Available Abstract Dyslipidemia is common in chronic hemodialysis patients and its underlying mechanism is complex. Hemodialysis causes an imbalance between antioxidants and production of reactive oxygen species, which induces the oxidative stress and thereby may lead to accelerated atherosclerosis. Statins have been found to be little effective in end-stage kidney disease and other lipid-lowering therapies have been only scarcely studied. The study aimed to assess the effect of low-dose fenofibrate therapy on plasma lipids and redox status in long-term hemodialysis patients with mild hypertriglyceridemia. Twenty seven chronic hemodialysis patients without any lipid-lowering therapy were included in a double-blind crossover, placebo-controlled study. The patients were randomized into two groups and were given a sequence of either 100 mg of fenofibrate per each hemodialysis day for 4 weeks or placebo with a week-long wash-out period between treatment periods. Plasma lipids, high sensitive C-reactive protein (CRP, urea, creatinine, electrolytes, phosphocreatine kinase (CK, GOT, GPT and plasma thiols (total and free glutathione, homocysteine, cysteine and cysteinylglycine were measured at baseline and after each of the study periods. Plasma aminothiols were measured by reversed phase HPLC with thiol derivatization with 2-chloro-1-methylquinolinium tetrafluoroborate. Fenofibrate therapy caused a significant decrease of total serum cholesterol, LDL cholesterol and triglycerides and an increase of HDL cholesterol. The treatment was well tolerated with no side-effects but there was a small but significant increase of CK not exceeding the upper limit of normal range. There were no changes of serum CRP, potassium, urea, and creatinine and liver enzymes during the treatment. Neither total nor total free cysteinylglycine and cysteine changed during the study but both total and free glutathione increased during the therapy with fenofibrate and the same was observed

  18. Chronic exposure to low doses of pharmaceuticals disturbs the hepatic expression of circadian genes in lean and obese mice

    Energy Technology Data Exchange (ETDEWEB)

    Anthérieu, Sébastien; Le Guillou, Dounia; Coulouarn, Cédric; Begriche, Karima [INSERM, U991, Université de Rennes 1, 35000 Rennes (France); Trak-Smayra, Viviane [Pathology Department, Saint-Joseph University, Beirut (Lebanon); Martinais, Sophie [INSERM, U991, Université de Rennes 1, 35000 Rennes (France); Porceddu, Mathieu [Mitologics SAS, Hôpital Robert Debré, 48 Boulevard Sérurier, 75019 Paris (France); Robin, Marie-Anne [INSERM, U991, Université de Rennes 1, 35000 Rennes (France); Fromenty, Bernard, E-mail: bernard.fromenty@inserm.fr [INSERM, U991, Université de Rennes 1, 35000 Rennes (France)

    2014-04-01

    Drinking water can be contaminated with pharmaceuticals. However, it is uncertain whether this contamination can be harmful for the liver, especially during obesity. Hence, the goal of our study was to determine whether chronic exposure to low doses of pharmaceuticals could have deleterious effects on livers of lean and obese mice. To this end, lean and ob/ob male mice were treated for 4 months with a mixture of 11 drugs provided in drinking water at concentrations ranging from 10 to 10{sup 6} ng/l. At the end of the treatment, some liver and plasma abnormalities were observed in ob/ob mice treated with the cocktail containing 10{sup 6} ng/l of each drug. For this dosage, a gene expression analysis by microarray showed altered expression of circadian genes (e.g. Bmal1, Dbp, Cry1) in lean and obese mice. RT-qPCR analyses carried out in all groups of animals confirmed that expression of 8 different circadian genes was modified in a dose-dependent manner. For some genes, a significant modification was observed for dosages as low as 10{sup 2}–10{sup 3} ng/l. Drug mixture and obesity presented an additive effect on circadian gene expression. These data were validated in an independent study performed in female mice. Thus, our study showed that chronic exposure to trace pharmaceuticals disturbed hepatic expression of circadian genes, particularly in obese mice. Because some of the 11 drugs can be found in drinking water at such concentrations (e.g. acetaminophen, carbamazepine, ibuprofen) our data could be relevant in environmental toxicology, especially for obese individuals exposed to these contaminants. - Highlights: • The contamination of drinking water with drugs may have harmful effects on health. • Some drugs can be more hepatotoxic in the context of obesity and fatty liver. • Effects of chronic exposure of trace drugs were studied in lean and obese mouse liver. Drugs and obesity present additive effects on circadian gene expression and toxicity. • Trace

  19. Age and Chronicity of Administration Dramatically Influenced the Impact of Low Dose Paraquat Exposure on Behavior and Hypothalamic-Pituitary-Adrenal Activity

    Directory of Open Access Journals (Sweden)

    Chris A. Rudyk

    2017-07-01

    Full Text Available Little is known of the age-dependent and long-term consequences of low exposure levels of the herbicide and dopaminergic toxicant, paraquat. Thus, we assessed the dose-dependent effects of paraquat using a typical short-term (3 week exposure procedure, followed by an assessment of the effects of chronic (16 weeks exposure to a very low dose (1/10th of what previously induced dopaminergic neuronal damage. Short term paraquat treatment dose-dependently induced deficits in locomotion, sucrose preference and Y-maze performance. Chronic low dose paraquat treatment had a very different pattern of effects that were also dependent upon the age of the animal: in direct contrast to the short-term effects, chronic low dose paraquat increased sucrose consumption and reduced forced swim test (FST immobility. Yet these effects were age-dependent, only emerging in mice older than 13 months. Likewise, Y-maze spontaneous alternations and home cage activity were dramatically altered as a function of age and paraquat chronicity. In both the short and long-term exposure studies, increased corticosterone and altered hippocampal glucocorticoid receptor (GR levels were induced by paraquat, but surprisingly these effects were blunted in the older mice. Thus, paraquat clearly acts as a systemic stressor in terms of corticoid signaling and behavioral outcomes, but that paradoxical effects may occur with: (a repeated exposure at; (b very low doses; and (c older age. Collectively, these data raise the possibility that repeated “hits” with low doses of paraquat in combination with aging processes might have promoted compensatory outcomes.

  20. Genomic instability in mutation induction on normal human fibroblasts irradiated with chronic low-dose radiations in heavy-ion radiation field

    International Nuclear Information System (INIS)

    Suzuki, M.; Tsuruoka, C.; Uchihori, Y.; Yasuda, H.; Fujitaka, K.

    2003-01-01

    Full text: At a time when manned space exploration is more a reality with the planned the International Space Station (ISS) underway, the potential exposure of crews in a spacecraft to chronic low-dose radiations in the field of low-flux galactic cosmic rays (GCR) and the subsequent biological effects have become one of the major concerns of space science. We have studied both in vitro life span and genomic instability in cellular effects in normal human skin fibroblasts irradiated with chronic low-dose radiations in heavy-ion radiation field. Cells were cultured in a CO2 incubator, which was set in the irradiation room for the biological study of heavy ions in the Heavy Ion Medical Accelerator in Chiba (HIMAC) at National Institute of Radiological Sciences (NIRS), and irradiated with scattered radiations produced from heavy ions. Absorbed dose measured using a thermoluminescence dosimeter (TLD) and a Si-semiconductor detector was to be around 1.4 mGy per day when operating the HIMAC machine for biological experiments. The total population doubling number (tPDN) of low-dose irradiated cells was significantly smaller (79-93%) than that of unirradiated cells. The results indicate that the life span of the cell population shortens by irradiating with low-dose scattered radiations in the heavy-ion irradiation field. Genomic instability in cellular responses was examined to measure either cell killing or mutation induction in low-dose accumulated cells after exposing to X-ray challenging doses. The results showed that there was no enhanced effect on cell killing between low-dose accumulated and unirradiated cells after exposing to defined challenging doses of 200kV X rays. On the contrary, the mutation frequency on hprt locus of low-dose accumulated cells was much higher than that of unirradiated cells. The results suggested that genomic instability was induced in mutagenesis by the chronic low-dose irradiations in heavy-ion radiation field

  1. Neuropsychological effects of chronic low-dose exposure to polychlorinated biphenyls (PCBs: A cross-sectional study

    Directory of Open Access Journals (Sweden)

    Klett Martin

    2005-10-01

    Full Text Available Abstract Background Exposure to indoor air of private or public buildings contaminated with polychlorinated biphenyls (PCBs has raised health concerns in long-term users. This exploratory neuropsychological group study investigated the potential adverse effects of chronic low-dose exposure to specific air-borne low chlorinated PCBs on well-being and behavioral measures in adult humans. Methods Thirty employees exposed to indoor air contaminated with PCBs from elastic sealants in a school building were compared to 30 non-exposed controls matched for education and age, controlling for gender (age range 37–61 years. PCB exposure was verified by external exposure data and biological monitoring (PCB 28, 101, 138, 153, 180. Subjective complaints, learning and memory, executive function, and visual-spatial function was assessed by standardized neuropsychological testing. Since exposure status depended on the use of contaminated rooms, an objectively exposed subgroup (N = 16; PCB 28 = 0.20 μg/l; weighted exposure duration 17.9 ± 7 years was identified and compared with 16 paired controls. Results Blood analyses indicated a moderate exposure effect size (d relative to expected background exposure for total PCB (4.45 ± 2.44 μg/l; d = 0.4. A significant exposure effect was found for the low chlorinated PCBs 28 (0.28 ± 0.25 μg/l; d = 1.5 and 101 (0.07 ± 0.09 μg/l; d = 0.7. Although no neuropsychological effects exceeded the adjusted significance level, estimation statistics showed elevated effect sizes for several variables. The objectively exposed subgroup showed a trend towards increased subjective attentional and emotional complaints (tiredness and slowing of practical activities, emotional state as well as attenuated attentional performance (response shifting and alertness in a cued reaction task. Conclusion Chronic inhalation of low chlorinated PCBs that involved elevated blood levels was associated with a subtle attenuation of emotional well

  2. Is low-dose amitriptyline effective in the management of chronic low back pain? Study protocol for a randomised controlled trial.

    Science.gov (United States)

    Urquhart, Donna M; Wluka, Anita E; Sim, Malcolm R; van Tulder, Maurits; Forbes, Andrew; Gibson, Stephen J; Arnold, Carolyn; Fong, Chris; Anthony, Shane N; Cicuttini, Flavia M

    2016-10-22

    Low back pain is a major clinical and public health problem, with limited evidence-based treatments. Low-dose antidepressants are commonly used to treat pain in chronic low back pain. However, their efficacy is unproven. The aim of this pragmatic, double-blind, randomised, placebo-controlled trial is to determine whether low-dose amitriptyline (an antidepressant) is more effective than placebo in reducing pain in individuals with chronic low back pain. One hundred and fifty individuals with chronic low back pain will be recruited through hospital and private medical and allied health clinics, advertising in local media and posting of flyers in community locations. They will be randomly allocated to receive either low-dose amitriptyline (25 mg) or an active placebo (benztropine mesylate, 1 mg) for 6 months. The primary outcome measure of pain intensity will be assessed at baseline, 3 and 6 months using validated questionnaires. Secondary measures of self-reported low back disability, work absence and hindrance in the performance of paid/unpaid work will also be examined. Intention-to-treat analyses will be performed. This pragmatic, double-blind, randomised, placebo-controlled trial will provide evidence regarding the effectiveness of low-dose antidepressants compared with placebo in reducing pain, disability, work absenteeism and hindrance in work performance in individuals with chronic low back pain. This trial has major public health and clinical importance as it has the potential to provide an effective approach to the management of chronic low back pain. Australian New Zealand Clinical Trials Registry: ACTRN12612000131853 ; registered on 30 January 2012.

  3. Combined evaluation of rest-redistribution thallium-201 tomography and low-dose dobutamine echocardiography enhances the identification of viable myocardium in patients with chronic coronary artery disease

    International Nuclear Information System (INIS)

    Pace, L.; Cuocolo, A.; Salvatore, M.; Perrone-Filardi, P.; Prastaro, M.; Vezzuto, P.; Crisci, T.; Dellegrottaglie, S.; Piscione, F.; Chiariello, M.; Mainenti, P.P.; Varrone, A.

    1998-01-01

    The purpose of this study was to evaluate whether combined evaluation by discriminant analysis of rest-redistribution thallium-201 tomography and low-dose dobutamine echocardiography enhances the accuracy in identifying viable myocardium in patients with chronic coronary artery disease. Rest-redistribution 201 Tl has high sensitivity but low specificity in identifying viable myocardium, while the opposite is true for low-dose dobutamine echocardiography. Forty-six patients underwent low-dose dobutamine echocardiography and rest-redistribution 201 Tl tomography on the same day. Rest echocardiography was repeated at least 30 days (mean 40±20) after myocardial revascularization. Discriminant analysis was applied to the results of 201 Tl tomography and dobutamine echocardiography to classify a/dyskinetic segments as viable or non-viable. In 92 a/dyskinetic segments that were revascularized, rest-redistribution 201 Tl tomography yielded an accuracy of 75%, while the accuracy of dobutamine echocardiography was 70% (P 201 Tl imaging are useful and complementary techniques for identifying viable myocardium in patients with chronic coronary artery disease. Combined evaluation by discriminant analysis significantly improves accuracy, although the cost-effectiveness of such an approach remains to be determined. (orig.)

  4. Chronic Low Dose Rate Ionizing Radiation Exposure Induces Premature Senescence in Human Fibroblasts that Correlates with Up Regulation of Proteins Involved in Protection against Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Olga Loseva

    2014-07-01

    Full Text Available The risks of non-cancerous diseases associated with exposure to low doses of radiation are at present not validated by epidemiological data, and pose a great challenge to the scientific community of radiation protection research. Here, we show that premature senescence is induced in human fibroblasts when exposed to chronic low dose rate (LDR exposure (5 or 15 mGy/h of gamma rays from a 137Cs source. Using a proteomic approach we determined differentially expressed proteins in cells after chronic LDR radiation compared to control cells. We identified numerous proteins involved in protection against oxidative stress, suggesting that these pathways protect against premature senescence. In order to further study the role of oxidative stress for radiation induced premature senescence, we also used human fibroblasts, isolated from a patient with a congenital deficiency in glutathione synthetase (GS. We found that these GS deficient cells entered premature senescence after a significantly shorter time of chronic LDR exposure as compared to the GS proficient cells. In conclusion, we show that chronic LDR exposure induces premature senescence in human fibroblasts, and propose that a stress induced increase in reactive oxygen species (ROS is mechanistically involved.

  5. Effects of chronic exposure to low doses of ionizing radiation on the reproductive performance and outcome of an exposed population

    International Nuclear Information System (INIS)

    Mannino, J.A.

    1978-01-01

    This study was designed to test the hypothesis that low doses of ionizing radiation (cumulative dose less than 5.0 rads/yr) effects the reproductive history and/or outcome of a human population. Medically-related personnel who were exposed to low doses of radiation in the course of their employment were compared with medically-related personnel who were not routinely exposed to ionizing radiation. Each population consisted of 3000 persons from the states of Michigan and Ohio. Reproductive performance, history, and outcome of each sample population was compared statistically. Nineteen congenital defects and 47 postnatal defects were recorded for conceptions of the non-exposed population and 50 congenital defects and 83 postnatal defects were recorded for the exposed group. These groups were further broken down as to whether conception took place before, during, or after exposure and the results statistically analyzed. It was found that the exposure population had greater than expected numbers of postnatal defects and less than expected numbers of normal conceptions

  6. Updated estimates of survival and cost effectiveness for imatinib versus interferon-alpha plus low-dose cytarabine for newly diagnosed chronic-phase chronic myeloid leukaemia.

    Science.gov (United States)

    Reed, Shelby D; Anstrom, Kevin J; Li, Yanhong; Schulman, Kevin A

    2008-01-01

    For trials in which participants are followed beyond the main study period to assess long-term outcomes, economic evaluations conducted using short-term data should be systematically updated to reflect new information. We used 60-month survival data from the IRIS (International Randomized study of Interferon vs STI571) trial to update previously published cost-effectiveness estimates, based on 19 months of follow-up, of imatinib versus interferon (IFN)-alpha plus low-dose cytarabine in patients with chronic-phase chronic myeloid leukaemia. For patients treated with imatinib, we used the 60-month data to calibrate the survival curves generated from the original cost-effectiveness model. We used historical data to model survival for patients randomized to IFNalpha. We updated costs for medical resources using 2006 Medicare reimbursement rates and applied average wholesale prices (AWPs) and wholesale acquisition costs (WACs) to study medications. Five-year survival for patients randomized to imatinib was better than predicted in the original model (89.4% vs 83.2%). We estimated remaining life expectancy with first-line imatinib to be 19.1 life-years (3.8 life-years over the original model) and 15.2 QALYs (3.1 QALYs over the original estimate). Estimates for IFNalpha remained at 9.1 life-years and 6.3 QALYs. When we applied AWPs to study medications, incremental cost-effectiveness ratios (ICERs) were $US 51,800-57,500 per QALY. When we applied WACs, ICERs were $US 42,000-46,200 per QALY. Although the analysis revealed that the original survival estimates were conservative, the updated cost-effectiveness ratios were consistent with, or slightly higher than, the original estimates, depending on the method for assigning costs to study medications.

  7. Dose-rate effects and chronological changes of chromosome aberration rates in spleen cells from mice that are chronically exposed to gamma-ray at low dose rates

    International Nuclear Information System (INIS)

    Tanaka, Kimio; Kohda, Atsushi; Ichinohe, Kazuaki; Matsumoto, Tsuneya; Oghiso, Yoichi

    2006-01-01

    Dose-rate effects have not been examined in the low dose-rate regions of less than 60-600 mGy/h. Mice were chronically exposed to gamma-ray at 20 mGy/day (approximately 1 mGy/h) up to 700 days and at 1 mGy/day (approximately 0.05 mGy/h) for 500 days under SPF conditions. Chronological changes of chromosome aberration rates in spleen cells were observed along with accumulated doses at both low dose-rates. Unstable aberrations increased in a biphasic manner within 0-2 Gy and 4-14 Gy in 20 mGy/day irradiation. They slightly increased up to 0.5 Gy in 1 mGy/day irradiation. Chromosome aberration rates at 20 mGy/day and 1 mGy/day were compared at the same total doses of 0.5 Gy and 0.25 Gy. They were 2.0 vs. 0.53, and 1.0 vs. 0.47 respectively. Thus, dose-rate effects were observed in these low dose-rate regions. (author)

  8. Human circulating plasma DNA significantly decreases while lymphocyte DNA damage increases under chronic occupational exposure to low-dose gamma-neutron and tritium β-radiation

    Energy Technology Data Exchange (ETDEWEB)

    Korzeneva, Inna B., E-mail: inna.korzeneva@molgen.vniief.ru [Russian Federal Nuclear Center – All-Russian Research Institute of Experimental Physics (RFNC-VNIIEF) 607190, Sarov, 37 Mira ave., Nizhniy Novgorod Region (Russian Federation); Kostuyk, Svetlana V.; Ershova, Liza S. [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, 115478 Moscow, 1 Moskvorechye str. (Russian Federation); Osipov, Andrian N. [Federal Medial and Biological Center named after Burnazyan of the Federal Medical and Biological Agency (FMBTz named after Burnazyan of FMBA), Moscow (Russian Federation); State Research Center - Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency, Zhivopisnaya, 46, Moscow, 123098 (Russian Federation); Zhuravleva, Veronika F.; Pankratova, Galina V. [Russian Federal Nuclear Center – All-Russian Research Institute of Experimental Physics (RFNC-VNIIEF) 607190, Sarov, 37 Mira ave., Nizhniy Novgorod Region (Russian Federation); Porokhovnik, Lev N.; Veiko, Natalia N. [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, 115478 Moscow, 1 Moskvorechye str. (Russian Federation)

    2015-09-15

    Highlights: • The chronic exposure to low-dose IR induces DSBs in human lymphocytes (TM index). • Exposure to IR decreases the level of human circulating DNA (cfDNA index). • IR induces an increase of DNase1 activity (DNase1 index) in plasma. • IR induces an increase of the level of antibodies to DNA (Ab DNA index) in plasma. • The ratio cfDNA/(DNase 1 × Ab DNA × TM) is a potential marker of human exposure to IR. - Abstract: The blood plasma of healthy people contains cell-fee (circulating) DNA (cfDNA). Apoptotic cells are the main source of the cfDNA. The cfDNA concentration increases in case of the organism’s cell death rate increase, for example in case of exposure to high-dose ionizing radiation (IR). The objects of the present research are the blood plasma and blood lymphocytes of people, who contacted occupationally with the sources of external gamma/neutron radiation or internal β-radiation of tritium N = 176). As the controls (references), blood samples of people, who had never been occupationally subjected to the IR sources, were used (N = 109). With respect to the plasma samples of each donor there were defined: the cfDNA concentration (the cfDNA index), DNase1 activity (the DNase1 index) and titre of antibodies to DNA (the Ab DNA index). The general DNA damage in the cells was defined (using the Comet assay, the tail moment (TM) index). A chronic effect of the low-dose ionizing radiation on a human being is accompanied by the enhancement of the DNA damage in lymphocytes along with a considerable cfDNA content reduction, while the DNase1 content and concentration of antibodies to DNA (Ab DNA) increase. All the aforementioned changes were also observed in people, who had not worked with the IR sources for more than a year. The ratio cfDNA/(DNase1 × Ab DNA × TM) is proposed to be used as a marker of the chronic exposure of a person to the external low-dose IR. It was formulated the assumption that the joint analysis of the cfDNA, DNase1, Ab

  9. Sperm mRNA transcripts are indicators of sub-chronic low dose testicular injury in the Fischer 344 rat.

    Directory of Open Access Journals (Sweden)

    Sara E Pacheco

    Full Text Available Current human reproductive risk assessment methods rely on semen and serum hormone analyses, which are not easily comparable to the histopathological endpoints and mating studies used in animal testing. Because of these limitations, there is a need to develop universal evaluations that reliably reflect male reproductive function. We hypothesized that toxicant-induced testicular injury can be detected in sperm using mRNA transcripts as indicators of insult. To test this, we exposed adult male Fischer 344 rats to low doses of model testicular toxicants and classically characterized the testicular injury while simultaneously evaluating sperm mRNA transcripts from the same animals. Overall, this study aimed to: 1 identify sperm transcripts altered after exposure to the model testicular toxicant, 2,5-hexanedione (HD using microarrays; 2 expand on the HD-induced transcript changes in a comprehensive time course experiment using qRT-PCR arrays; and 3 test these injury indicators after exposure to another model testicular toxicant, carbendazim (CBZ. Microarray analysis of HD-treated adult Fischer 344 rats identified 128 altered sperm mRNA transcripts when compared to control using linear models of microarray analysis (q<0.05. All transcript alterations disappeared after 3 months of post-exposure recovery. In the time course experiment, time-dependent alterations were observed for 12 candidate transcripts selected from the microarray data based upon fold change and biological relevance, and 8 of these transcripts remained significantly altered after the 3-month recovery period (p<0.05. In the last experiment, 8 candidate transcripts changed after exposure to CBZ (p<0.05. The two testicular toxicants produced distinct molecular signatures with only 4 overlapping transcripts between them, each occurring in opposite directions. Overall, these results suggest that sperm mRNA transcripts are indicators of low dose toxicant-induced testicular injury in the rat.

  10. DNA methylation and potential multigenerational epigenetic effects linked to uranium chronic low-dose exposure in gonads of males and females rats.

    Science.gov (United States)

    Elmhiri, G; Gloaguen, C; Grison, S; Kereselidze, D; Elie, C; Tack, K; Benderitter, M; Lestaevel, P; Legendre, A; Souidi, M

    2018-01-05

    An increased health problem in industrialised countries is the contemporary concern of public and scientific community as well. This has been attributed in part to accumulated environmental pollutants especially radioactive substances and the use of nuclear power plants worldwide. However, the outcome of chronic exposure to low doses of a radionuclide such as uranium remains unknown. Recently, a paradigm shift in the perception of risk of radiotoxicology has emerged through investigating the possibility of transmission of biological effects over generations, in particular by epigenetic pathways. These processes are known for their crucial roles associated with the development of several diseases. The current work investigates the epigenetic effect of chronic exposure to low doses of uranium and its inheritance across generations. Materials and Methods To test this proposition, a rodent multigenerational model, males and females, were exposed to a non-toxic concentration of uranium (40mgL -1 drinking water) for nine months. The uranium effects on were evaluated over three generations (F0, F1 and F2) by analysing the DNA methylation profile and DNMT genes expression in ovaries and testes tissues. Here we report a significant hypermethylation of testes DNA (p <0.005) whereas ovaries showed hypomethylated DNA (p <0.005). Interestingly, this DNA methylation profile was significantly maintained across generations F0, F1 and F2. Furthermore, qPCR results of both tissues imply a significant change in the expression of DNA methyltransferase genes (DNMT 1 and DNMT3a/b) as well. Altogether, our work demonstrates for the first time a sex-dependance and inheritance of epigenetic marks, DNA methylation, as a biological response to the exposure to low doses of uranium. However, it is not clear which type of reproductive cell type is more responsive in this context. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Effects of chronic exposure of seeds and seeds and seedlings of Arabidopsis Thaliana by low doses of γ-radiation on plant growth and development

    International Nuclear Information System (INIS)

    Litvinov, S.V.

    2013-01-01

    Article presents the results of research on the effect of chronic γ-irradiation in small doses on A. Thaliana seedlings and seeds growth and development. Exposure rate for the seeds was 0,45 mGy/h (total absorbed dose 30 cSv) and 0,18 mGy/h for seedlings (total absorbed dose 3 cSv). Statistically significant differences in the germination capacity, in the time of primary leaf rosette formation, in the hypocotyl length were revealed between irradiated and control seedlings. Plants from irradiated seeds differed by the higher growth rate of stem, they flowered and fruited earlier, but they also characterized on average shorter vegetative cycle in comparison with control plants. In our experiments it is shown significant impact of chronic low doses of γ-irradiation of seeds and seedlings on the ontogeny in A. Thaliana and on the parameters that reflect the growth and development of the irradiated plants

  12. Dietary supplementation with low-dose omega-3 fatty acids reduces salivary tumor necrosis factor-α levels in patients with chronic periodontitis: a randomized controlled clinical study.

    Science.gov (United States)

    Keskiner, I; Saygun, I; Bal, V; Serdar, M; Kantarci, A

    2017-08-01

    Recent studies have demonstrated the beneficial effects of omega-3 polyunsaturated fatty acids (PUFAs) on physiological processes and on a variety of chronic inflammatory diseases, including periodontal diseases. In this study, we evaluated the impact of omega-3 PUFAs in conjunction with scaling and root planing (SRP) on salivary markers in patients with chronic periodontitis. Thirty systemically healthy subjects with chronic periodontitis were enrolled and randomly allocated into two groups. The control group (n = 15) was treated with SRP + placebo whereas the test group was treated with SRP and dietary supplementation of low-dose omega-3 PUFAs (6.25 mg eicosapentaenoic acid and 19.19 mg docosahexaenoic acid). Clinical parameters were taken at baseline, 1, 3 and 6 mo following therapy. Saliva samples were obtained at the same time intervals and analyzed for tumor necrosis factor-α (TNF-α) and superoxide dismutase (SOD). Both groups showed significant changes in clinical parameters in response to treatment compared to baseline with no significant difference between groups. Salivary TNF-α levels showed a statistically significant decrease in the test group at 6 mo compared to the control group. Salivary SOD levels increased significantly at 3 and 6 mo in the test group and at 6 mo in placebo groups compared to baseline with no statistically significant differences between the groups. The results demonstrated that dietary supplementation with low-dose omega-3 PUFAs improves salivary TNF-α without any significant impact on clinical parameters in patients with chronic periodontitis, suggesting that the systemic benefits of dietary omega-3 PUFAs may not be translated to periodontal health. (ClinicalTrials.gov ID NCT02719587). © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Methylation changes in muscle and liver tissues of male and female mice exposed to acute and chronic low-dose X-ray-irradiation

    International Nuclear Information System (INIS)

    Kovalchuk, Olga; Burke, Paula; Besplug, Jill; Slovack, Mark; Filkowski, Jody; Pogribny, Igor

    2004-01-01

    The biological and genetic effects of chronic low-dose radiation (LDR) exposure and its relationship to carcinogenesis have received a lot of attention in the recent years. For example, radiation-induced genome instability, which is thought to be a precursor of tumorogenesis, was shown to have a transgenerational nature. This indicates a possible involvement of epigenetic mechanisms in LDR-induced genome instability. Genomic DNA methylation is one of the most important epigenetic mechanisms. Existing data on radiation effects on DNA methylation patterns is limited, and no one has specifically studied the effects of the LDR. We report the first study of the effects of whole-body LDR exposure on global genome methylation in muscle and liver tissues of male and female mice. In parallel, we evaluated changes in promoter methylation and expression of the tumor suppressor gene p16 INKa and DNA repair gene O 6 -methylguanine-DNA methyltransferase (MGMT). We observed different patterns of radiation-induced global genome DNA methylation in the liver and muscle of exposed males and females. We also found sex and tissue-specific differences in p16 INKa promoter methylation upon LDR exposure. In male liver tissue, p16 INKa promoter methylation was more pronounced than in female tissue. In contrast, no significant radiation-induced changes in p16 INKa promoter methylation were noted in the muscle tissue of exposed males and females. Radiation also did not significantly affect methylation status of MGMT promoter. We also observed substantial sex differences in acute and chronic radiation-induced expression of p16 INKa and MGMT genes. Another important outcome of our study was the fact that chronic low-dose radiation exposure proved to be a more potent inducer of epigenetic effects than the acute exposure. This supports previous findings that chronic exposure leads to greater genome destabilization than acute exposure

  14. Effect of chronic low dose natural radiation in human peripheral blood mononuclear cells: Evaluation of DNA damage and repair using the alkaline comet assay

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, P.R. Vivek, E-mail: prvkumar06@gmail.com [Low Level Radiation Research Laboratory, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, IRE Campus, Beach Road, Kollam 691 001, Kerala (India); Seshadri, M. [Low Level Radiation Research Section, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Jaikrishan, G. [Low Level Radiation Research Laboratory, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, IRE Campus, Beach Road, Kollam 691 001, Kerala (India); Das, Birajalaxmi [Low Level Radiation Research Section, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    2015-05-15

    Highlights: • Effect of chronic low dose natural radiation in radio adaptive response studied. • PBMCs of subjects from NLNRA and HLNRA were challenged with gamma radiation. • DNA damage and repair in PBMCs was compared using the alkaline comet assay. • Significant reduction in DNA damage in subjects of high dose group from HLNRA noted. • Probable induction of an in vivo radio adaptive response in subjects from HLNRA. - Abstract: This study investigates whether peripheral blood mononuclear cells (PBMCs) from inhabitants of Kerala in southwest India, exposed to chronic low dose natural radiation in vivo (>1 mSv year{sup −1}), respond with a radioadaptive response to a challenging dose of gamma radiation. Toward this goal, PBMCs isolated from 77 subjects from high-level natural radiation areas (HLNRA) and 37 subjects from a nearby normal level natural radiation area (NLNRA) were challenged with 2 Gy and 4 Gy gamma radiation. Subjects from HLNRA were classified based on the mean annual effective dose received, into low dose group (LDG) and high dose group (HDG) with mean annual effective doses of 2.69 mSv (N = 43, range 1.07 mSv year{sup −1} to 5.55 mSv year{sup −1}) and 9.62 mSv (N = 34, range 6.07 mSv year{sup −1} to17.41 mSv year{sup −1}), respectively. DNA strand breaks and repair kinetics (at 7 min, 15 min and 30 min after 4 Gy) were evaluated using the alkaline single cell gel electrophoresis (comet) assay. Initial levels of DNA strand breaks observed after either a 2 Gy or a 4 Gy challenging dose were significantly lower in subjects of the HDG from HLNRA compared to subjects of NLNRA (2 Gy, P = 0.01; 4 Gy, P = 0.02) and LDG (2 Gy P = 0.01; 4 Gy, P = 0.05). Subjects of HDG from HLNRA showed enhanced rejoining of DNA strand breaks (HDG/NLNRA, P = 0.06) during the early stage of repair (within 7 min). However at later times a similar rate of rejoining of strand breaks was observed across the groups (HDG, LDG and NLNRA). Preliminary results from

  15. Low-Dose Tramadol and Non-Steroidal Anti-Inflammatory Drug Combination Therapy Prevents the Transition to Chronic Low Back Pain.

    Science.gov (United States)

    Inage, Kazuhide; Orita, Sumihisa; Yamauchi, Kazuyo; Suzuki, Takane; Suzuki, Miyako; Sakuma, Yoshihiro; Kubota, Go; Oikawa, Yasuhiro; Sainoh, Takeshi; Sato, Jun; Fujimoto, Kazuki; Shiga, Yasuhiro; Abe, Koki; Kanamoto, Hirohito; Inoue, Masahiro; Kinoshita, Hideyuki; Takahashi, Kazuhisa; Ohtori, Seiji

    2016-08-01

    Retrospective study. To determine whether low-dose tramadol plus non-steroidal anti-inflammatory drug combination therapy could prevent the transition of acute low back pain to chronic low back pain. Inadequately treated early low back pain transitions to chronic low back pain occur in approximately 30% of affected individuals. The administration of non-steroidal anti-inflammatory drugs is effective for treatment of low back pain in the early stages. However, the treatment of low back pain that is resistant to non-steroidal anti-inflammatory drugs is challenging. Patients who presented with acute low back pain at our hospital were considered for inclusion in this study. After the diagnosis of acute low back pain, non-steroidal anti-inflammatory drug administration was started. Forty patients with a visual analog scale score of >5 for low back pain 1 month after treatment were finally enrolled. The first 20 patients were included in a non-steroidal anti-inflammatory drug group, and they continued non-steroidal anti-inflammatory drug therapy for 1 month. The next 20 patients were included in a combination group, and they received low-dose tramadol plus non-steroidal anti-inflammatory drug combination therapy for 1 month. The incidence of adverse events and the improvement in the visual analog scale score at 2 months after the start of treatment were analyzed. No adverse events were observed in the non-steroidal anti-inflammatory drug group. In the combination group, administration was discontinued in 2 patients (10%) due to adverse events immediately following the start of tramadol administration. At 2 months, the improvement in the visual analog scale score was greater in the combination group than in the non-steroidal anti-inflammatory drug group (ppain to chronic low back pain.

  16. Human circulating plasma DNA significantly decreases while lymphocyte DNA damage increases under chronic occupational exposure to low-dose gamma-neutron and tritium β-radiation.

    Science.gov (United States)

    Korzeneva, Inna B; Kostuyk, Svetlana V; Ershova, Liza S; Osipov, Andrian N; Zhuravleva, Veronika F; Pankratova, Galina V; Porokhovnik, Lev N; Veiko, Natalia N

    2015-09-01

    The blood plasma of healthy people contains cell-fee (circulating) DNA (cfDNA). Apoptotic cells are the main source of the cfDNA. The cfDNA concentration increases in case of the organism's cell death rate increase, for example in case of exposure to high-dose ionizing radiation (IR). The objects of the present research are the blood plasma and blood lymphocytes of people, who contacted occupationally with the sources of external gamma/neutron radiation or internal β-radiation of tritium N = 176). As the controls (references), blood samples of people, who had never been occupationally subjected to the IR sources, were used (N = 109). With respect to the plasma samples of each donor there were defined: the cfDNA concentration (the cfDNA index), DNase1 activity (the DNase1 index) and titre of antibodies to DNA (the Ab DNA index). The general DNA damage in the cells was defined (using the Comet assay, the tail moment (TM) index). A chronic effect of the low-dose ionizing radiation on a human being is accompanied by the enhancement of the DNA damage in lymphocytes along with a considerable cfDNA content reduction, while the DNase1 content and concentration of antibodies to DNA (Ab DNA) increase. All the aforementioned changes were also observed in people, who had not worked with the IR sources for more than a year. The ratio cfDNA/(DNase1×Ab DNA × TM) is proposed to be used as a marker of the chronic exposure of a person to the external low-dose IR. It was formulated the assumption that the joint analysis of the cfDNA, DNase1, Ab DNA and TM values may provide the information about the human organism's cell resistivity to chronic exposure to the low-dose IR and about the development of the adaptive response in the organism that is aimed, firstly, at the effective cfDNA elimination from the blood circulation, and, secondly - at survival of the cells, including the cells with the damaged DNA. Copyright © 2015. Published by Elsevier B.V.

  17. Assessment of pulmonary function using pixel indexes of multiple-slice spiral CT low-dose two-phase scanning in chronic obstructive pulmonary disease

    International Nuclear Information System (INIS)

    Zhang Lihua; Wang Yunhua; Jiang Zhongbiao; Zhang Lejun; Sun Wanli; Zhang Chunming

    2012-01-01

    Objective: To explore the values of pixel indexes (PI) with multiple-slice spiral CT low-dose two-phase scanning for assessing the pulmonary function in chronic obstructive pulmonary disease (COPD). Methods: Thirty-six patients with COPD (COPD group)and 30 healthy people (control group)underwent pulmonary function test (PFT). Chest 64-MSCT low-dose (50 mAs) scanning at full inspiration and expiration, routine scanning (100 mAs) at inspiration were performed. The effective dose (ED) was calculated. The lung was divided into three regions (upper, middle, lower). PI of lung were divided into five groups: -960--1024, -910--960, -800--910, -700--800, -400--700. The PI -910 (sum of the PI under -910 HU) of low-dose scanning at each region were measured and calculated using pulmo software. All PI included PIin -910 , PIiex -910 , PIin -910 -PIiex -910 , PIiex -910 /PIin -910 and (PIin -910 -PIiex -910 )/PIin -910 . All patients underwent PFT within 3 days after 64-MSCT canning, FEV1% and FEV1/FVC were selected for comparison. Results: The PIin in three regions (-960 - -1024, -910 - -960, -800 - -910) were statistically significant between normal and COPD groups (U=0.00, 57.00, 20.50, P<0.01). The PIex in all regions were statistically significant (U=0.00, 0.00, 71.52, 191.00, 6.00, P<0.01). PI -910--1024 at expiration and inspiration were correlated with FEV1% and FEV1/FVC (r=-0.548, -0.664, -0.752, -0.781, P<0.01). PIin -910 , PIex -910 ,PIiex -910 /PIin -910 , (PIin -910 -PIex -910 )/PIin -910 had a good correlation with FEV1% and FEV1/FVC (r=-0.548, -0.664, -0.752, -0.781, -0.674, -0.642, 0.674, 0.642, P<0.01). Conclusion: Pixel indexes of 64-MSCT low-dose two-phase scanning can be used to evaluate pulmonary function in COPD patients. (authors)

  18. Use of low-dose oral theophylline as an adjunct to inhaled corticosteroids in preventing exacerbations of chronic obstructive pulmonary disease: study protocol for a randomised controlled trial.

    Science.gov (United States)

    Devereux, Graham; Cotton, Seonaidh; Barnes, Peter; Briggs, Andrew; Burns, Graham; Chaudhuri, Rekha; Chrystyn, Henry; Davies, Lisa; De Soyza, Anthony; Fielding, Shona; Gompertz, Simon; Haughney, John; Lee, Amanda J; McCormack, Kirsty; McPherson, Gladys; Morice, Alyn; Norrie, John; Sullivan, Anita; Wilson, Andrew; Price, David

    2015-06-10

    Chronic obstructive pulmonary disease (COPD) is associated with high morbidity, mortality, and health-care costs. An incomplete response to the anti-inflammatory effects of inhaled corticosteroids is present in COPD. Preclinical work indicates that 'low dose' theophylline improves steroid responsiveness. The Theophylline With Inhaled Corticosteroids (TWICS) trial investigates whether the addition of 'low dose' theophylline to inhaled corticosteroids has clinical and cost-effective benefits in COPD. TWICS is a randomised double-blind placebo-controlled trial conducted in primary and secondary care sites in the UK. The inclusion criteria are the following: an established predominant respiratory diagnosis of COPD (post-bronchodilator forced expiratory volume in first second/forced vital capacity [FEV1/FVC] of less than 0.7), age of at least 40 years, smoking history of at least 10 pack-years, current inhaled corticosteroid use, and history of at least two exacerbations requiring treatment with antibiotics or oral corticosteroids in the previous year. A computerised randomisation system will stratify 1424 participants by region and recruitment setting (primary and secondary) and then randomly assign with equal probability to intervention or control arms. Participants will receive either 'low dose' theophylline (Uniphyllin MR 200 mg tablets) or placebo for 52 weeks. Dosing is based on pharmacokinetic modelling to achieve a steady-state serum theophylline of 1-5 mg/l. A dose of theophylline MR 200 mg once daily (or placebo once daily) will be taken by participants who do not smoke or participants who smoke but have an ideal body weight (IBW) of not more than 60 kg. A dose of theophylline MR 200 mg twice daily (or placebo twice daily) will be taken by participants who smoke and have an IBW of more than 60 kg. Participants will be reviewed at recruitment and after 6 and 12 months. The primary outcome is the total number of participant-reported COPD exacerbations requiring

  19. [Study of genome instability using DNA fingerprinting of the offspring of male mice subjected to chronic low dose gamma irradiation].

    Science.gov (United States)

    Bezlepkin, V G; Vasil'eva, G V; Lomaeva, M G; Sirota, N P; Gaziev, A I

    2000-01-01

    By a polymerase chain reaction with an arbitrary primer (AP-PCR), the possibility of transmission of genome instability to somatic cells of the offspring (F1 generation) from male parents of mice exposed to chronic low-level gamma-radiation was studied. Male BALB/c mice 15 days after exposure to 10-50 cGy were mated with unirradiated females. Biopsies were taken from tale tips of two month-old offspring mice and DNA was isolated. The primer in the AP-PCR was a 20-mer oligonucleotide flanking the microsatellite locus Atp1b2 on chromosome 11 of the mouse. A comparative analysis of individual fingerprints of AP-PCR products on DNA-templates from the offspring of irradiated and unirradiated male mice revealed an increased variability of microsatellite-associated sequences in the genome of the offspring of the males exposed to 25 and 50 cGy. The DNA-fingerprints of the offspring of male mice exposed to chronic irradiation with the doses 10 and 25 cGy 15 days before fertilization (at the post-meiotic stage of spermatogenesis) showed an increased frequency of "non-parent bands". The results of the study point to the possibility of transmission to the offspring somatic cells of changes increasing genome instability from male parents exposed to chronic low-level radiation prior to fertilization.

  20. Maintenance of remission with low-dose olopatadine hydrochloride for itch in well-controlled chronic urticaria

    Directory of Open Access Journals (Sweden)

    Makino T

    2012-09-01

    Full Text Available Teruhiko Makino,1 Yoshiaki Takegami,1 Mati Ur Rehman,1 Yoko Yoshihisa,1 Waka Ishida,2 Takashi Toyomoto,3 Tadamichi Shimizu11Department of Dermatology, University of Toyama, Toyama, Japan; 2Department of Dermatology, Niigata Central Hospital, Joetsu, Japan; 3Department of Dermatology, Saiseikai Takaoka Hospital, Takaoka, JapanBackground: The long-term follow-up of chronic urticaria (CU is important to ensure the adequate treatment of patients. Olopatadine hydrochloride is one of the second-generation nonsedating antihistamines.Methods: This study was designed to assess the optimal dose of olopatadine to suppress symptoms of chronic urticarial itch in well-controlled patients. After CU patients were treated with 10 mg olopatadine, patients having a visual analogue scale (VAS itch score of less than 20 were randomly allocated into one of three groups: 10 mg/day (n = 35, 5 mg/day (n = 30, or no medication (n = 32.Results: The suppressive effects of both the 5 mg and 10 mg olopatadine treatments on the VAS itch score were more significant and longer lasting over a period of 4 weeks than the no-medication treatment. Both the 5-mg group and the 10-mg group showed improved urticarial symptoms and maintained their VAS itch score within normal limits compared to the no-medication group. The differences between the 5-mg and 10-mg groups were not significant.Conclusion: These results demonstrate that treatment with olopatadine at a dose of 5 mg once daily is effective and safe for the management and prevention of CU symptoms for itch in well-controlled patients.Keywords: chronic urticaria, olopatadine, dose, antihistamine, itch, histamine

  1. Phase II study of palliative low-dose local radiotherapy in disseminated indolent non-Hodgkin's lymphoma and chronic lymphocytic leukemia

    DEFF Research Database (Denmark)

    Jóhannsson, Jakob; Specht, Lena; Mejer, Johannes

    2002-01-01

    of the palliative effect of this regimen in patients with disseminated INHL or CLL. METHODS AND MATERIALS: Twenty-two patients (11 men, 11 women, median age 62 years, range 30-89) with disseminated INHL (n = 15) or CLL (n = 7) were treated with local low-dose RT, 2 Gy x 2 within 3 days, with the aim of achieving......PURPOSE: Indolent non-Hodgkin's lymphoma (INHL) and chronic lymphocytic leukemia (CLL) are highly sensitive to radiotherapy (RT). Previous retrospective studies have shown high response rates after local palliative RT of 4 Gy in 2 fractions, which prompted this prospective Phase II trial...... palliation from localized lymphoma masses. The patients were treated to a total of 31 different sites. Seventeen patients had previously been treated with chemotherapy. The median observation time after the start of RT was 8 months (range 3-26). RESULTS: All patients and all irradiated sites were assessable...

  2. 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.)

  3. Chronic exposure of adult, postnatal and in utero rat models to low-dose 137Cesium: impact on circulating biomarkers

    International Nuclear Information System (INIS)

    Manens, Line; Grison, Stéphane; Bertho, Jean-Marc; Lestaevel, Philippe; Guéguen, Yann; Benderitter, Marc; Aigueperse, Jocelyne; Souidi, Maâmar

    2016-01-01

    The presence of 137 Cesium ( 137 Cs) in the environment after nuclear accidents at Chernobyl and more recently Fukushima Daiichi raises many health issues for the surrounding populations chronically exposed through the food chain. To mimic different exposure situations, we set up a male rat model of exposure by chronic ingestion of a 137 Cs concentration likely to be ingested daily by residents of contaminated areas (6500 Bq.l −1 ) and tested contaminations lasting 9 months for adult, neonatal and fetal rats. We tested plasma and serum biochemistry to identify disturbances in general indicators (lipids, proteins, carbohydrates and electrolytes) and in biomarkers of thyroid, heart, brain, bone, kidney, liver and testis functions. Analysis of the general indicators showed increased levels of cholesterol (+26%), HDL cholesterol (+31%), phospholipids B (+15%) and phosphorus (+100%) in the postnatal group only. Thyroid, heart, brain, bone and kidney functions showed no blood changes in any model. The liver function evaluation showed changes in total bilirubin (+67%) and alkaline phosphatase (–11%) levels, but only for the rats exposed to 137 Cs intake in adulthood. Large changes in 17β-estradiol (–69%) and corticosterone (+36%) levels affected steroidogenesis, but only in the adult model. This study showed that response profiles differed according to age at exposure: lipid metabolism was most radiosensitive in the postnatal model, and steroid hormone metabolism was most radiosensitive in rats exposed in adulthood. There was no evidence of deleterious effects suggesting a potential impact on fertility or procreation.

  4. Metabolomics reveals dose effects of low-dose chronic exposure to uranium in rats: identification of candidate biomarkers in urine samples.

    Science.gov (United States)

    Grison, Stéphane; Favé, Gaëlle; Maillot, Matthieu; Manens, Line; Delissen, Olivia; Blanchardon, Éric; Dublineau, Isabelle; Aigueperse, Jocelyne; Bohand, Sandra; Martin, Jean-Charles; Souidi, Maâmar

    2016-01-01

    Data are sparse about the potential health risks of chronic low-dose contamination of humans by uranium (natural or anthropogenic) in drinking water. Previous studies report some molecular imbalances but no clinical signs due to uranium intake. In a proof-of-principle study, we reported that metabolomics is an appropriate method for addressing this chronic low-dose exposure in a rat model (uranium dose: 40 mg L -1 ; duration: 9 months, n = 10). In the present study, our aim was to investigate the dose-effect pattern and identify additional potential biomarkers in urine samples. Compared to our previous protocol, we doubled the number of rats per group (n = 20), added additional sampling time points (3 and 6 months) and included several lower doses of natural uranium (doses used: 40, 1.5, 0.15 and 0.015 mg L -1 ). LC-MS metabolomics was performed on urine samples and statistical analyses were made with SIMCA-P+ and R packages. The data confirmed our previous results and showed that discrimination was both dose and time related. Uranium exposure was revealed in rats contaminated for 9 months at a dose as low as 0.15 mg L -1 . Eleven features, including the confidently identified N1-methylnicotinamide, N1-methyl-2-pyridone-5-carboxamide and 4-hydroxyphenylacetylglycine, discriminated control from contaminated rats with a specificity and a sensitivity ranging from 83 to 96 %, when combined into a composite score. These findings show promise for the elucidation of underlying radiotoxicologic mechanisms and the design of a diagnostic test to assess exposure in urine, in a dose range experimentally estimated to be above a threshold between 0.015 and 0.15 mg L -1 .

  5. Evaluation of the genotoxic effects of chronic low-dose ionizing radiation exposure on nuclear medicine workers

    Energy Technology Data Exchange (ETDEWEB)

    Sahin, Ali [Department of Nuclear Medicine, Faculty of Medicine, Medical School, Ataturk University, Erzurum (Turkey)], E-mail: alibabam2001@yahoo.com; Tatar, Abdulgani; Oztas, Sitki [Department of Genetics, Faculty of Medicine, Ataturk University, 25240 Erzurum (Turkey); Seven, Bedri; Varoglu, Erhan [Department of Nuclear Medicine, Faculty of Medicine, Medical School, Ataturk University, Erzurum (Turkey); Yesilyurt, Ahmet [Department of Genetics, Faculty of Medicine, Ataturk University, 25240 Erzurum (Turkey); Ayan, Arif Kursad [Department of Nuclear Medicine, Faculty of Medicine, Medical School, Ataturk University, Erzurum (Turkey)

    2009-07-15

    Introduction: Nuclear medicine workers are occupationally exposed to chronic ionizing radiation. It is known that ionizing radiation may have damaging effects on chromosomes. In the present study, we investigated the genotoxic effects of ionizing radiation on nuclear medicine workers. We used two different indicators of genotoxicity methods: sister chromatid exchange (SCE) and micronucleus (MN). Methods: The present research was carried out using 21 nuclear medicine workers (11 females and 10 males) during two periods: during normal working conditions and after a 1-month vacation. The radiation dose varied from 1.20 to 48.56 mSv, which accumulated during the occupational exposure time between two vacations. Peripheral blood samples were taken from each subject for two distinct lymphocyte cultures (SCE and MN) in each period. Results: In nearly all subjects, SCE values increased significantly during radiation exposure compared to the postvacation period (P<.05). Similarly, MN frequencies in most of the subjects increased significantly during radiation exposure compared to the postvacation period (P<.05). Conclusions: This study revealed that both SCE and MN frequencies in most of the subjects were significantly higher during exposure to ionizing radiation than after a 1-month vacation period. However, this genotoxic effect was reversible in most of the subjects.

  6. Evaluation of the genotoxic effects of chronic low-dose ionizing radiation exposure on nuclear medicine workers

    International Nuclear Information System (INIS)

    Sahin, Ali; Tatar, Abdulgani; Oztas, Sitki; Seven, Bedri; Varoglu, Erhan; Yesilyurt, Ahmet; Ayan, Arif Kursad

    2009-01-01

    Introduction: Nuclear medicine workers are occupationally exposed to chronic ionizing radiation. It is known that ionizing radiation may have damaging effects on chromosomes. In the present study, we investigated the genotoxic effects of ionizing radiation on nuclear medicine workers. We used two different indicators of genotoxicity methods: sister chromatid exchange (SCE) and micronucleus (MN). Methods: The present research was carried out using 21 nuclear medicine workers (11 females and 10 males) during two periods: during normal working conditions and after a 1-month vacation. The radiation dose varied from 1.20 to 48.56 mSv, which accumulated during the occupational exposure time between two vacations. Peripheral blood samples were taken from each subject for two distinct lymphocyte cultures (SCE and MN) in each period. Results: In nearly all subjects, SCE values increased significantly during radiation exposure compared to the postvacation period (P<.05). Similarly, MN frequencies in most of the subjects increased significantly during radiation exposure compared to the postvacation period (P<.05). Conclusions: This study revealed that both SCE and MN frequencies in most of the subjects were significantly higher during exposure to ionizing radiation than after a 1-month vacation period. However, this genotoxic effect was reversible in most of the subjects.

  7. On the development of neoplasma in dogs after chronic gamma-irradiation at a low dose rate

    International Nuclear Information System (INIS)

    Yakovleva, V.I.

    1978-01-01

    In order to estimate end effects of chronic prolonged gamma irradiation of dogs, an exposure of 80 animals to irradiation was terminated and they were followed up closely. Out of 80 animals 30 dogs (Ist series) were irradiated for 3 years and 50 dogs (2 series) for 6 years. The dogs were exposed to irradiation at doses of 21 to 190 rad per year. Out of the total number of animals 22 dogs died. Post-mortem examinations showed neoplasms in 13 animals (7 malignant and 12 benign neoplasms). The highest number of tumors developed in dogs of the 2 series (10 out of 11) one-two years after irradiation (6 malignant tumors-malignant pheochro--mocytoma of adrenals; malignant adenoma of the hypophysis: polymorphocellular sarcoma of the liver; leucomyosarcoma of the uterus; blader cancer; breast cancer; and 10 benign tumors-pancreatic adenoma; liver angioma; 2 papillary adenomas of the prostate; 3 renal adenomas; lipoma; polyps of the gall-bladder). Animals of the 1-st series displayed 3 neoplasms (1 malignant tumor-bladder tumor and 2 benign tumors-liver hepatoma and spleen angioma) 4-5 years after irradiation

  8. Examination of Chronic Smoking Behavior and Eligibility for Low-Dose Computed Tomography for Lung Cancer Screening Among Older Chinese Male Smokers.

    Science.gov (United States)

    Li, Chien-Ching; Matthews, Alicia K; Dong, XinQi

    2017-07-01

    Low-dose computed tomography lung cancer (LDCT) screening is an effective way to decrease lung cancer mortality. Both Medicare and private insurers offer coverage of LDCT screening to beneficiaries who are at high risk of developing lung cancer. In this study, we examined rates and predictors of chronic smoking behavior and eligibility for coverage of LDCT screening among older Chinese men living in the greater Chicago area. Data were obtained from the Population Study of Chinese Elderly in Chicago, a population-based survey of community-dwelling, older Chinese adults in the Chicago metropolitan area. Eligibility criteria according to Centers of Medicare and Medicaid Services (CMS) and U.S. Preventive Services Task Force (USPSTF) for LDCT screening were used. Multivariate logistic regression was conducted to determine predictors of chronic smoking behavior which was operationalized as meeting criteria for LDCT screening. A quarter of the sample were current smokers and 42.5% reported a prior history of smoking. Eighteen percent and 22% of older Chinese men met the eligibility criteria for appropriateness for CMS and USPSTF LDCT screening, respectively. Furthermore, education, marital status, and number of children were significantly associated with chronic smoking behavior. Older Chinese men with chronic smoking behavior are at high risk of developing lung cancer and nearly one in five meet eligibility for LDCT screening. Increased outreach and education regarding early detection of lung cancer and smoking cessation are needed for this vulnerable and high-risk population. © The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. UVA-induced mutational spectra in the laci gene from transgenic mouse skin

    International Nuclear Information System (INIS)

    Gorelick, N.J.; O'Kelly, J.A.; Biedermann, K.A.

    1995-01-01

    The UVB (295-320 nm) component of sunlight was once thought to be the sole cause of photoaging and skin cancer. However, there is now compelling evidence to suggest that chronic irradiation with UVA (320-400 nm) is a significant component of the etiologies of these diseases. To identify acute markers of UVA damage, we investigated UVA-induced mutagenesis in vivo by using a lacI transgenic mouse mutation assay. The backs of adult female C57BL/6 Big Blue reg-sign mice were shaved and exposed daily to a low or a high dose of UVA for 5 consecutive days. One group remained unexposed. The high dose of UVA significantly increased the mutant frequency in skin determined 12 days after the last exposure. Mutant frequencies were (Avg ± SEM, n=7-8/group): 6.1 ± 0.5 x 10 -5 (high dose). DNA sequence analysis of mutant lacI genes demonstrated that the high dose of UVA produced a different mutational spectrum compared to control. The mutational spectrum from the low dose mutants was not different from the control spectrum in skin generated previously; the predominant classes of recovered mutations were GC→At transitions at CpG sites (11/35) and GC →TA transversions (12/35). In contrast, in the high dose group, GC →AT transitions at non-CpG sites predominated (61/97 mutations); three tandem base substitutions (1 GG →AA; 2 CC→TT) were uniquely recovered; and an increased frequency of recovered GC→CG substitutions was observed (12/97 vs. none in controls). The recovered high dose spectrum is consistent with the types of DNA damage generated by UVA as well as by reactive oxygen species. These studies demonstrate that UVA is mutagenic in vivo and that this assay can be used to study early events in UVA-induced skin damage

  10. 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

  11. Iterative reconstruction technique vs filter back projection: utility for quantitative bronchial assessment on low-dose thin-section MDCT in patients with/without chronic obstructive pulmonary disease

    Energy Technology Data Exchange (ETDEWEB)

    Koyama, Hisanobu; Seki, Shinichiro; Sugimura, Kazuro [Kobe University Graduate School of Medicine, Division of Radiology, Department of Radiology, Kobe, Hyogo (Japan); Ohno, Yoshiharu; Nishio, Mizuho; Matsumoto, Sumiaki; Yoshikawa, Takeshi [Kobe University Graduate School of Medicine, Advanced Biomedical Imaging Research Centre, Kobe (Japan); Kobe University Graduate School of Medicine, Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe (Japan); Sugihara, Naoki [Toshiba Medical Systems Corporation, Ohtawara, Tochigi (Japan)

    2014-08-15

    The aim of this study was to evaluate the utility of the iterative reconstruction (IR) technique for quantitative bronchial assessment during low-dose computed tomography (CT) as a substitute for standard-dose CT in patients with/without chronic obstructive pulmonary disease. Fifty patients (mean age, 69.2; mean % predicted FEV1, 79.4) underwent standard-dose CT (150mAs) and low-dose CT (25mAs). Except for tube current, the imaging parameters were identical for both protocols. Standard-dose CT was reconstructed using filtered back-projection (FBP), and low-dose CT was reconstructed using IR and FBP. For quantitative bronchial assessment, the wall area percentage (WA%) of the sub-segmental bronchi and the airway luminal volume percentage (LV%) from the main bronchus to the peripheral bronchi were acquired in each dataset. The correlation and agreement of WA% and LV% between standard-dose CT and both low-dose CTs were statistically evaluated. WA% and LV% between standard-dose CT and both low-dose CTs were significant correlated (r > 0.77, p < 0.00001); however, only the LV% agreement between SD-CT and low-dose CT reconstructed with IR was moderate (concordance correlation coefficient = 0.93); the other agreement was poor (concordance correlation coefficient <0.90). Quantitative bronchial assessment via low-dose CT has potential as a substitute for standard-dose CT by using IR and airway luminal volumetry techniques. circle Quantitative bronchial assessment of COPD using low-dose CT is possible. (orig.)

  12. 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

  13. 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.)

  14. Chronic UVA (365-nm) irradiation induced scratching in hairless mice: dose-time dependency and the effect of ketanserin

    International Nuclear Information System (INIS)

    Laat, J.M.T. de; Groenendijk, M.; Vloten, W.A. van; Gruijl, F.R. de; Seite, S.

    1997-01-01

    In a study on the dose-response relationship for longwave UVA (UVA1; 340-400 nm) carcinogenesis in hairless mice scratch marks appeared after months of daily exposure as an unwanted side effect. Tumor induction in the highest of the 4 tested dose groups (receiving a daily dose of 430 kJ/m 2 of 365-nm radiation) could not be determined because extensive scarification occurred prior to the development of any tumors. The induction of scratch marks could be scored and quantified in all 4 dose groups tested. The UVA1 dose-dependencies for the induction of tumors and scratch marks were compared. We found that the induction of scratch marks depended mainly on the cumulative UVA1 exposure, whereas tumor induction showed a lesser dose-dependency. An attempt was made to prevent the apparent pruritogenic effect of UVA1 irradiation and to understand its mechanism. The influence of ketanserin, a serotonin/histamine antagonist, on the UVA1 induction of scratch marks was tested in groups of 8 mice daily irradiated with 430 kJ/m 2 . No difference was found between treated and untreated animals. Histological examination of skin biopsies from irradiated mice from the 430-kJ/m 2 dose group from the UVA1 carcinogenic experiment, showed no changes in numbers of mast cells or other inflammatory features when compared to skin biopsies from unirradiated control mice. This indicated that UVA1-induced scratching is not mediated through mast cell release of serotonin and/or histamine. An adequate therapeutic treatment which can prevent UVA1-induced scratching would enable us to test tumor induction with UVA1 over a larger dose range, and may provide additional insight in how this radiation damages the skin. It remains conjectural whether there exists and analogous UVA-induced pruritus in human skin. (au)

  15. N-Acetyl Cysteine does not prevent liver toxicity from chronic low dose plus sub-acute high dose paracetamol exposure in young or old mice

    Science.gov (United States)

    Kane, Alice-Elizabeth; Huizer-Pajkos, Aniko; Mach, John; McKenzie, Catriona; Mitchell, Sarah-Jayne; de Cabo, Rafael; Jones, Brett; Cogger, Victoria; Le Couteur, David G; Hilmer, Sarah-Nicole

    2016-01-01

    Paracetamol is an analgesic commonly used by people of all ages, which is well documented to cause severe hepatotoxicity with acute over-exposures. The risk of hepatotoxicity from non-acute paracetamol exposures is less extensively studied, and this is the exposure most common in older adults. Evidence on the effectiveness of N-acetyl cysteine (NAC) for non-acute paracetamol exposures, in any age group, is lacking. This study aimed to examine the effect of long-term exposure to therapeutic doses of paracetamol and sub-acute paracetamol over-exposure, in young and old mice, and to investigate whether NAC was effective at preventing paracetamol hepatotoxicity induced by these exposures. Young and old male C57BL/6 mice were fed a paracetamol-containing (1.33g/kg food) or control diet for 6 weeks. Mice were then dosed orally 8 times over 3 days with additional paracetamol (250mg/kg) or saline, followed by either one or two doses of oral NAC (1200mg/kg) or saline. Chronic low-dose paracetamol exposure did not cause hepatotoxicity in young or old mice, measured by serum alanine aminotransferase (ALT) elevation, and confirmed by histology and a DNA fragmentation assay. Sub-acute paracetamol exposure caused significant hepatotoxicity in young and old mice, measured by biochemistry (ALT) and histology. Neither a single nor double dose of NAC protected against this toxicity from sub-acute paracetamol in young or old mice. This finding has important clinical implications for treating toxicity due to different paracetamol exposure types in patients of all ages, and implies a need to develop new treatments for sub-acute paracetamol toxicity. PMID:26821200

  16. No adaptive response is induced by chronic low-dose radiation from Ra-226 in the CHSE/F fish embryonic cell line and the HaCaT human epithelial cell line

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Xiaopei, E-mail: shix22@mcmaster.ca; Mothersill, Carmel; Seymour, Colin

    2016-11-15

    Purpose: To determine whether chronic low-dose α-particle radiation from Ra-226 over multiple cell generations can lead to an adaptive response in CHSE/F fish embryonic cells or HaCaT human epithelial cells receiving subsequent acute high-dose γ-ray radiation. Methods: CHSE/F and HaCaT cells were exposed to very low doses of Ra-226 in medium for multiple generations prior to being challenged by a higher dose γ-ray radiation. The clonogenic assay was used to test the clonogenic survival of cells with or without being pretreated by radiation from Ra-226. Results: In general, pretreatment with chronic radiation has no significant influence on the reaction of cells to the subsequent challenge radiation. Compared to unprimed cells, the change in clonogenic survival of primed cells after receiving challenge radiation is mainly due to the influence of the chronic exposure, and there's little adaptive response induced. However at several dose points, pretreatment of CHSE/F fish cells with chronic radiation resulted in a radiosensitive response to a challenge dose of γ-ray radiation, and pretreatment of HaCaT cells resulted in no effect except for a slightly radioresistant response to the challenge radiation which was not significant. Conclusion: The results suggest that chronic low-dose radiation is not effective enough to induce adaptive response. There was a difference between human and fish cells and it may be important to consider results from multiple species before making conclusions about effects of chronic or low doses of radiation in the environment. The term “radiosensitive” or “adaptive” make no judgment about whether such responses are ultimately beneficial or harmful. - Highlights: • No obvious adaptive response is induced by chronic low-dose radiation from Ra-226. • Priming radiation from Ra-226 sensitized CHSE/F cells to the challenge radiation. • Linear model is inconsistent with current work using chronic low-dose radiation.

  17. Automated assessment of aortic and main pulmonary arterial diameters using model-based blood vessel segmentation for predicting chronic thromboembolic pulmonary hypertension in low-dose CT lung screening

    Science.gov (United States)

    Suzuki, Hidenobu; Kawata, Yoshiki; Niki, Noboru; Sugiura, Toshihiko; Tanabe, Nobuhiro; Kusumoto, Masahiko; Eguchi, Kenji; Kaneko, Masahiro

    2018-02-01

    Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by obstruction of the pulmonary vasculature by residual organized thrombi. A morphological abnormality inside mediastinum of CTEPH patient is enlargement of pulmonary artery. This paper presents an automated assessment of aortic and main pulmonary arterial diameters for predicting CTEPH in low-dose CT lung screening. The distinctive feature of our method is to segment aorta and main pulmonary artery using both of prior probability and vascular direction which were estimated from mediastinal vascular region using principal curvatures of four-dimensional hyper surface. The method was applied to two datasets, 64 lowdose CT scans of lung cancer screening and 19 normal-dose CT scans of CTEPH patients through the training phase with 121 low-dose CT scans. This paper demonstrates effectiveness of our method for predicting CTEPH in low-dose CT screening.

  18. Impact of low-dose chronic exposure to Bisphenol A (BPA) on adult male zebrafish adaption to the environmental complexity: Disturbing the color preference patterns and reliving the anxiety behavior.

    Science.gov (United States)

    Li, Xiang; Sun, Ming-Zhu; Li, Xu; Zhang, Shu-Hui; Dai, Liang-Ti; Liu, Xing-Yu; Zhao, Xin; Chen, Dong-Yan; Feng, Xi-Zeng

    2017-11-01

    The extensive usage of xenobiotic endocrine disrupting chemicals (XEDCs), such as Bisphenol A (BPA), has created obvious threat to aquatic ecosystems worldwide. Although a comprehensive understanding of the adverse effect of BPA on behaviors and physiology have been proven, the potential impact of low-dose BPA on altering the basic ability of aquatic organism in adapting to the surrounded complex environment still remains elusive. In this research, we report that treatment of adult male zebrafish with chronic (7 weeks) low-dose (0.22 nM-2.2 nM) BPA, altered the ability in adapting the complex environment by disturbing the natural color preference patterns. In addition, chronic 50 ng/L (0.22 nM) BPA exposure alleviated the anxiety behavior of male zebrafish confronted with the novel environment by enhancing the preference towards light in the light/dark preference test. This phenotype was associated with less expression of serotonin (5-TH) in the hypothalamus and the down-regulation of tyrosine hydroxylase (TH) in brain tissues. As such, our results show that low-dose BPA remnant in surface waters altered zebrafish behavior that are known to have ecological and evolutionary consequences. Here we reported that the impact of chronic low-dose BPA exposure on the basic capability of zebrafish to adapt to the environmental complexity. Specifically, BPA at low concentration, under the environmental safety level and 3000-fold lower than the accepted human daily exposure, interfered with the ability to discriminate color and alleviate anxiety induced by the novel environment, which finally altered the capability of male zebrafish to adapt to the environmental complexity. These findings revealed the ecological effect of low-dose BPA and regular BPA concentration standard are not necessarily safe. The result also provided the consideration of retuning the hazard concentration level of BPA. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Prediction of improvement in global left ventricular function in patients with chronic coronary artery disease and impaired left ventricular function: rest thallium-201 SPET versus low-dose dobutamine echocardiography

    International Nuclear Information System (INIS)

    Pace, L.; Salvatore, M.; Perrone-Filardi, P.; Dellegrottaglie, S.; Prastaro, M.; Crisci, T.; Ponticelli, M.P.; Piscione, F.; Chiariello, M.; Storto, G.; Della Morte, A.M.

    2000-01-01

    Accurate assessment of myocardial viability permits selection of patients who would benefit from myocardial revascularization. Currently, rest-redistribution thallium-201 scintigraphy and low-dose dobutamine echocardiography are among the most used techniques for the identification of viable myocardium. Thirty-one consecutive patients (all men, mean age 60±8 years) with chronic coronary artery disease and reduced left ventricular ejection fraction (31%±7%) were studied. Rest 201 Tl single-photon emission tomography (SPET), low-dose dobutamine echocardiography and radionuclide angiography were performed before revascularization. Radionuclide angiography and echocardiography were repeated after revascularization. An a/dyskinetic segment was considered viable on 201 Tl SPET when tracer uptake was >65%, while improvement on low-dose dobutamine echocardiography was considered a marker of viability. Increase in global ejection fraction was considered significant at ≥5%. In identifying viable segments, rest 201 Tl SPET showed higher sensitivity than low-dose dobutamine echocardiography (72% vs 53%, P 201 Tl SPET in group 1 than in group 2 (2.6±1.9 vs 0.6±1.2, P 201 Tl SPET and post-revascularization changes in ejection fraction (r=0.52, P 201 Tl SPET had a higher sensitivity (82% vs 53%, P=0.07) and showed a trend towards higher accuracy and specificity (77% vs 58%, and 71% vs 64%, respectively) as compared with low-dose dobutamine echocardiography. In conclusion, these findings suggest that when severely reduced global function is present, rest 201 Tl SPET evaluation of viability is more accurate than low-dose dobutamine echocardiography for the identification of patients who will benefit most from revascularization. (orig.)

  20. Neural Plasticity Associated with Hippocampal PKA-CREB and NMDA Signaling Is Involved in the Antidepressant Effect of Repeated Low Dose of Yueju Pill on Chronic Mouse Model of Learned Helplessness

    Directory of Open Access Journals (Sweden)

    Zhilu Zou

    2017-01-01

    Full Text Available Yueju pill is a traditional Chinese medicine formulated to treat syndromes of mood disorders. Here, we investigated the therapeutic effect of repeated low dose of Yueju in the animal model mimicking clinical long-term depression condition and the role of neural plasticity associated with PKA- (protein kinase A- CREB (cAMP response element binding protein and NMDA (N-methyl-D-aspartate signaling. We showed that a single low dose of Yueju demonstrated antidepressant effects in tests of tail suspension, forced swim, and novelty-suppressed feeding. A chronic learned helplessness (LH protocol resulted in a long-term depressive-like condition. Repeated administration of Yueju following chronic LH remarkably alleviated all of depressive-like symptoms measured, whereas conventional antidepressant fluoxetine only showed a minor improvement. In the hippocampus, Yueju and fluoxetine both normalized brain-derived neurotrophic factor (BDNF and PKA level. Only Yueju, not fluoxetine, rescued the deficits in CREB signaling. The chronic LH upregulated the expression of NMDA receptor subunits NR1, NR2A, and NR2B, which were all attenuated by Yueju. Furthermore, intracerebraventricular administration of NMDA blunted the antidepressant effect of Yueju. These findings supported the antidepressant efficacy of repeated routine low dose of Yueju in a long-term depression model and the critical role of CREB and NMDA signaling.

  1. Neural Plasticity Associated with Hippocampal PKA-CREB and NMDA Signaling Is Involved in the Antidepressant Effect of Repeated Low Dose of Yueju Pill on Chronic Mouse Model of Learned Helplessness.

    Science.gov (United States)

    Zou, Zhilu; Chen, Yin; Shen, Qinqin; Guo, Xiaoyan; Zhang, Yuxuan; Chen, Gang

    2017-01-01

    Yueju pill is a traditional Chinese medicine formulated to treat syndromes of mood disorders. Here, we investigated the therapeutic effect of repeated low dose of Yueju in the animal model mimicking clinical long-term depression condition and the role of neural plasticity associated with PKA- (protein kinase A-) CREB (cAMP response element binding protein) and NMDA (N-methyl-D-aspartate) signaling. We showed that a single low dose of Yueju demonstrated antidepressant effects in tests of tail suspension, forced swim, and novelty-suppressed feeding. A chronic learned helplessness (LH) protocol resulted in a long-term depressive-like condition. Repeated administration of Yueju following chronic LH remarkably alleviated all of depressive-like symptoms measured, whereas conventional antidepressant fluoxetine only showed a minor improvement. In the hippocampus, Yueju and fluoxetine both normalized brain-derived neurotrophic factor (BDNF) and PKA level. Only Yueju, not fluoxetine, rescued the deficits in CREB signaling. The chronic LH upregulated the expression of NMDA receptor subunits NR1, NR2A, and NR2B, which were all attenuated by Yueju. Furthermore, intracerebraventricular administration of NMDA blunted the antidepressant effect of Yueju. These findings supported the antidepressant efficacy of repeated routine low dose of Yueju in a long-term depression model and the critical role of CREB and NMDA signaling.

  2. Mimicking the effects of spaceflight on bone: Combined effects of disuse and chronic low-dose rate radiation exposure on bone mass in mice

    Science.gov (United States)

    Yu, Kanglun; Doherty, Alison H.; Genik, Paula C.; Gookin, Sara E.; Roteliuk, Danielle M.; Wojda, Samantha J.; Jiang, Zhi-Sheng; McGee-Lawrence, Meghan E.; Weil, Michael M.; Donahue, Seth W.

    2017-11-01

    During spaceflight, crewmembers are subjected to biomechanical and biological challenges including microgravity and radiation. In the skeleton, spaceflight leads to bone loss, increasing the risk of fracture. Studies utilizing hindlimb suspension (HLS) as a ground-based model of spaceflight often neglect the concomitant effects of radiation exposure, and even when radiation is accounted for, it is often delivered at a high-dose rate over a very short period of time, which does not faithfully mimic spaceflight conditions. This study was designed to investigate the skeletal effects of low-dose rate gamma irradiation (8.5 cGy gamma radiation per day for 20 days, amounting to a total dose of 1.7 Gy) when administered simultaneously to disuse from HLS. The goal was to determine whether continuous, low-dose rate radiation administered during disuse would exacerbate bone loss in a murine HLS model. Four groups of 16 week old female C57BL/6 mice were studied: weight bearing + no radiation (WB+NR), HLS + NR, WB + radiation exposure (WB+RAD), and HLS+RAD. Surprisingly, although HLS led to cortical and trabecular bone loss, concurrent radiation exposure did not exacerbate these effects. Our results raise the possibility that mechanical unloading has larger effects on the bone loss that occurs during spaceflight than low-dose rate radiation.

  3. 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.)

  4. Low dose epidemiology

    International Nuclear Information System (INIS)

    Tirmarche, M.; Hubert, P.

    1992-01-01

    Actually, epidemiological studies have to establish if the assessment of cancer risk can be verified at low chronic radiation doses. The population surveillance must be very long, the side effects and cancers of such radiation appearing much later. In France, this epidemiological study on nuclear workers have been decided recently. Before describing the experiment and french projects in epidemiology of nuclear workers, the authors present the main english and american studies

  5. Chemoimmunotherapy for relapsed/refractory and progressive 17p13-deleted chronic lymphocytic leukemia (CLL) combining pentostatin, alemtuzumab, and low-dose rituximab is effective and tolerable and limits loss of CD20 expression by circulating CLL cells.

    Science.gov (United States)

    Zent, Clive S; Taylor, Ronald P; Lindorfer, Margaret A; Beum, Paul V; LaPlant, Betsy; Wu, Wenting; Call, Timothy G; Bowen, Deborah A; Conte, Michael J; Frederick, Lori A; Link, Brian K; Blackwell, Sue E; Veeramani, Suresh; Baig, Nisar A; Viswanatha, David S; Weiner, George J; Witzig, Thomas E

    2014-07-01

    Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL) patients with purine analog refractory disease or TP53 dysfunction still have limited treatment options and poor survival. Alemtuzumab-containing chemoimmunotherapy regimens can be effective but frequently cause serious infections. We report a Phase II trial testing the efficacy and tolerability of a short-duration regimen combining pentostatin, alemtuzumab, and low-dose high-frequency rituximab designed to decrease the risk of treatment-associated infections and to limit the loss of CD20 expression by CLL cells. The study enrolled 39 patients with progressive CLL that was either relapsed/refractory (n = 36) or previously untreated with 17p13 deletion (17p13-) (n = 3). Thirteen (33%) patients had both 17p13- and TP53 mutations predicted to be dysfunctional, and eight patients had purine analog refractory CLL without TP53 dysfunction. Twenty-six (67%) patients completed therapy, with only five (13%) patients having treatment-limiting toxicity and no treatment-related deaths. Twenty-two (56%) patients responded to treatment, with 11 (28%) complete responses (four with incomplete bone marrow recovery). Median progression-free survival was 7.2 months, time to next treatment was 9.1 months, and overall survival was 34.1 months. The majority of deaths (82%) were caused by progressive disease, including transformed diffuse large B-cell lymphoma (n = 6). Correlative studies showed that low-dose rituximab activates complement and natural killer cells without a profound and sustained decrease in expression of CD20 by circulating CLL cells. We conclude that pentostatin, alemtuzumab, and low-dose high-frequency rituximab is a tolerable and effective therapy for CLL and that low-dose rituximab therapy can activate innate immune cytotoxic mechanisms without substantially decreasing CD20 expression. © 2014 Wiley Periodicals, Inc.

  6. Damage to the testes of a marine fish, the plaice (Pleuronectes platessa), induced by chronic exposure to low dose rate radiation

    International Nuclear Information System (INIS)

    Knowles, J.F.

    1999-01-01

    Although most authorised disposals of liquid radioactive waste are to the sea, effects of chronic radiation exposure on reproductive endpoints in a marine fish have not so far been investigated. For this reason we have carried out a series of experiments into effects of chronic radiation exposure on plaice, a commercially important marine food species which spends much of its life in contact with sea bed sediments where exposure from radioactive contaminants have been shown to be highest

  7. Chemoimmunotherapy for Relapsed/Refractory and Progressive 17p13 Deleted Chronic Lymphocytic Leukemia (CLL) Combining Pentostatin, Alemtuzumab, and Low Dose Rituximab is Effective and Tolerable and Limits Loss of CD20 Expression by Circulating CLL Cells

    Science.gov (United States)

    Zent, Clive S.; Taylor, Ronald P.; Lindorfer, Margaret A.; Beum, Paul V.; LaPlant, Betsy; Wu, Wenting; Call, Timothy G.; Bowen, Deborah A.; Conte, Michael J.; Frederick, Lori A.; Link, Brian K.; Blackwell, Sue E.; Veeramani, Suresh; Baig, Nisar A.; Viswanatha, David S.; Weiner, George J.; Witzig, Thomas E.

    2014-01-01

    Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL) patients with purine analogue refractory disease or TP53 dysfunction still have limited treatment options and poor survival. Alemtuzumab containing chemoimmunotherapy regimens can be effective but frequently cause serious infections. We report a phase II trial testing the efficacy and tolerability of a short duration regimen combining pentostatin, alemtuzumab, and low dose high frequency rituximab (PAR) designed to decrease the risk of treatment associated infections and limit loss of CD20 expression by CLL cells. The study enrolled 39 patients with progressive CLL that was either relapsed/refractory (n=36) or previously untreated with 17p13 deletion (17p13-)(n=3). Thirteen (33%) patients had both 17p13- and TP53 mutations predicted to be dysfunctional and eight patients had purine analogue refractory CLL without TP53 dysfunction. Twenty-six (67%) patients completed therapy with only five (13%) patients having treatment limiting toxicity, and no treatment related deaths. Twenty-two (56%) patients responded to treatment with 11 (28%) complete responses (four with incomplete bone marrow recovery). Median progression free survival was 7.2 months, time to next treatment 9.1 months, and overall survival 34.1 months. The majority of deaths (82%) were caused by progressive disease including transformed diffuse large B cell lymphoma (n=6). Correlative studies showed that low dose rituximab activates complement and NK cells without a profound and sustained decrease in expression of CD20 by circulating CLL cells. We conclude that PAR is a tolerable and effective therapy for CLL and that low dose rituximab therapy can activate innate immune cytotoxic mechanisms without substantially decreasing CD20 expression. PMID:24723493

  8. Effect of omega 3 fatty acids plus low-dose aspirin on both clinical and biochemical profiles of patients with chronic periodontitis and type 2 diabetes: a randomized double blind placebo-controlled study.

    Science.gov (United States)

    Elwakeel, N M; Hazaa, H H

    2015-12-01

    The aim of this study was, first, to investigate the effect of omega 3 (ω3) fatty acids plus low-dose aspirin with closed debridement in the treatment of patients with periodontitis and type 2 diabetes mellitus (DM), and second, to estimate the expression of monocyte chemoattractant protein-3 (MCP-3) in response to the supposed modulatory therapy. Forty patients with chronic periodontitis and type 2 DM were equally divided into groups 1 (patients received ω3 plus low-dose aspirin for 6 mo) and 2 (patients received placebo during the same period). Evaluation was done clinically (pocket depth, clinical attachment loss, gingival index and plaque index) and biochemically by estimating levels of interleukin 1β and MCP-3 in gingival crevicular fluid, plus investigating the effect of treatment on glycemic control by levels of glycated hemoglobin A1c in serum. All data were collected at baseline, 3 and 6 mo after treatment. Subjects of group 1 showed a highly significant reduction in pocket depth, clinical attachment loss, gingival index (p ≤ 0.01) after 3 and 6 mo compared to group 2. Glycated hemoglobin A1c levels showed a reduction in both groups at the end of the study period, with a non-significant difference (p > 0.05). Furthermore, the treatment protocol showed a significant reduction in levels of MCP-3 and interleukin 1β at 3 and 6 mo compared to the placebo group. Within the limits of the present study, ω3 plus low-dose aspirin proved effective as an adjunct to closed periodontal therapy in the management of patients with periodontitis and type 2 DM. Moreover, MCP-3 was proven to be effective both in the pathogenesis of the disease and as a biomarker in evaluating the response to periodontal treatment. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Phase II study of palliative low-dose local radiotherapy in disseminated indolent non-Hodgkin's lymphoma and chronic lymphocytic leukemia

    DEFF Research Database (Denmark)

    Jóhannsson, Jakob; Specht, Lena; Mejer, Johannes

    2002-01-01

    Indolent non-Hodgkin's lymphoma (INHL) and chronic lymphocytic leukemia (CLL) are highly sensitive to radiotherapy (RT). Previous retrospective studies have shown high response rates after local palliative RT of 4 Gy in 2 fractions, which prompted this prospective Phase II trial of the palliative...

  10. A prospective study of whether radiation pneumonitis is influenced by low-dose irradiated lung volume in primary lung cancer with chronic pulmonary disease

    International Nuclear Information System (INIS)

    Niibe, Yuzuru; Hayakawa, Kazushige; Masuda, Noriyuki; Yoshimura, Hirokuni

    2007-01-01

    The current study prospectively investigated the optimal dose-volume condition in cases of lung cancer with chronic pulmonary disease compared to those without chronic pulmonary disease. Cases of primary lung cancer treated with intended curative radiation therapy were registered in the current study. Their fraction size was limited to 2-3 Gy, so-called standard fractionation. They were prescribed a total dose of 60 Gy for non-small cell lung cancer (NSCLC; n=17) and a total dose of 54 Gy for small cell lung cancer (SCLC; n=4). Of the 21 patients enrolled in this study, 4 had chronic pulmonary disease (study arm), and the others had no chronic pulmonary disease (control arm). Seven received chemotherapy. Symptomatic radiation pneumonitis occurred in 5. Of the four patients in the study arm, two (50%) experienced symptomatic radiation pneumonitis; only 3 of the 17 patients in the control arm (17.6%) experienced symptomatic radiation pneumonitis. Furthermore, the median V 20 of patients who experienced symptomatic radiation pneumonitis in the study arm was 14%, which was higher than that of patients with no symptomatic radiation pneumonitis in the study arm, 5.8%. On the other hand, in the control arm, the median V 20 of patients with symptomatic radiation pneumonitis was 14.2%, about the same as that of patients with no symptomatic radiation pneumonitis in the control arm, 15.1%. The current study suggested that, as much as 15% of V 20 , might play an important role in cases of lung cancer with chronic pulmonary disease. (author)

  11. Are radiosensitivity data derived from natural field conditions consistent with data from controlled exposures? A case study of Chernobyl wildlife chronically exposed to low dose rates.

    Science.gov (United States)

    Garnier-Laplace, J; Geras'kin, S; Della-Vedova, C; Beaugelin-Seiller, K; Hinton, T G; Real, A; Oudalova, A

    2013-07-01

    The discrepancy between laboratory or controlled conditions ecotoxicity tests and field data on wildlife chronically exposed to ionising radiation is presented for the first time. We reviewed the available chronic radiotoxicity data acquired in contaminated fields and used a statistical methodology to support the comparison with knowledge on inter-species variation of sensitivity to controlled external γ irradiation. We focus on the Chernobyl Exclusion Zone and effects data on terrestrial wildlife reported in the literature corresponding to chronic dose rate exposure situations (from background ~100 nGy/h up to ~10 mGy/h). When needed, we reconstructed the dose rate to organisms and obtained consistent unbiased data sets necessary to establish the dose rate-effect relationship for a number of different species and endpoints. Then, we compared the range of variation of radiosensitivity of species from the Chernobyl-Exclusion Zone with the statistical distribution established for terrestrial species chronically exposed to purely gamma external irradiation (or chronic Species radioSensitivity Distribution - SSD). We found that the best estimate of the median value (HDR50) of the distribution established for field conditions at Chernobyl (about 100 μGy/h) was eight times lower than the one from controlled experiments (about 850 μGy/h), suggesting that organisms in their natural environmental were more sensitive to radiation. This first comparison highlights the lack of mechanistic understanding and the potential confusion coming from sampling strategies in the field. To confirm the apparent higher sensitive of wildlife in the Chernobyl Exclusion Zone, we call for more a robust strategy in field, with adequate design to deal with confounding factors. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Are radiosensitivity data derived from natural field conditions consistent with data from controlled exposures? A case study of Chernobyl wildlife chronically exposed to low dose rates

    International Nuclear Information System (INIS)

    Garnier-Laplace, J.; Geras’kin, S.; Della-Vedova, C.; Beaugelin-Seiller, K.; Hinton, T.G.; Real, A.; Oudalova, A.

    2013-01-01

    The discrepancy between laboratory or controlled conditions ecotoxicity tests and field data on wildlife chronically exposed to ionising radiation is presented for the first time. We reviewed the available chronic radiotoxicity data acquired in contaminated fields and used a statistical methodology to support the comparison with knowledge on inter-species variation of sensitivity to controlled external γ irradiation. We focus on the Chernobyl Exclusion Zone and effects data on terrestrial wildlife reported in the literature corresponding to chronic dose rate exposure situations (from background∼100 nGy/h up to ∼10 mGy/h). When needed, we reconstructed the dose rate to organisms and obtained consistent unbiased data sets necessary to establish the dose rate–effect relationship for a number of different species and endpoints. Then, we compared the range of variation of radiosensitivity of species from the Chernobyl-Exclusion Zone with the statistical distribution established for terrestrial species chronically exposed to purely gamma external irradiation (or chronic Species radioSensitivity Distribution – SSD). We found that the best estimate of the median value (HDR 50 ) of the distribution established for field conditions at Chernobyl (about 100 μGy/h) was eight times lower than the one from controlled experiments (about 850 μGy/h), suggesting that organisms in their natural environmental were more sensitive to radiation. This first comparison highlights the lack of mechanistic understanding and the potential confusion coming from sampling strategies in the field. To confirm the apparent higher sensitive of wildlife in the Chernobyl Exclusion Zone, we call for more a robust strategy in field, with adequate design to deal with confounding factors. -- Highlights: ► Discrepancy between controlled tests and Chernobyl effects data on wildlife was examined. ► We proposed a method to correct the dosimetry used for Chernobyl wildlife. ► Wildlife from the

  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. Granzyme B mediates both direct and indirect cleavage of extracellular matrix in skin after chronic low-dose ultraviolet light irradiation.

    Science.gov (United States)

    Parkinson, Leigh G; Toro, Ana; Zhao, Hongyan; Brown, Keddie; Tebbutt, Scott J; Granville, David J

    2015-02-01

    Extracellular matrix (ECM) degradation is a hallmark of many chronic inflammatory diseases that can lead to a loss of function, aging, and disease progression. Ultraviolet light (UV) irradiation from the sun is widely considered as the major cause of visible human skin aging, causing increased inflammation and enhanced ECM degradation. Granzyme B (GzmB), a serine protease that is expressed by a variety of cells, accumulates in the extracellular milieu during chronic inflammation and cleaves a number of ECM proteins. We hypothesized that GzmB contributes to ECM degradation in the skin after UV irradiation through both direct cleavage of ECM proteins and indirectly through the induction of other proteinases. Wild-type and GzmB-knockout mice were repeatedly exposed to minimal erythemal doses of solar-simulated UV irradiation for 20 weeks. GzmB expression was significantly increased in wild-type treated skin compared to nonirradiated controls, colocalizing to keratinocytes and to an increased mast cell population. GzmB deficiency significantly protected against the formation of wrinkles and the loss of dermal collagen density, which was related to the cleavage of decorin, an abundant proteoglycan involved in collagen fibrillogenesis and integrity. GzmB also cleaved fibronectin, and GzmB-mediated fibronectin fragments increased the expression of collagen-degrading matrix metalloproteinase-1 (MMP-1) in fibroblasts. Collectively, these findings indicate a significant role for GzmB in ECM degradation that may have implications in many age-related chronic inflammatory diseases. © 2014 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

  15. New radiobiological findings bearing on the 1977 ICRP recommendations. [Sensitivity of mouse and monkey prenatal oocytes to chronic, low-dose, tritium exposure

    Energy Technology Data Exchange (ETDEWEB)

    Dobson, R.L.

    1979-02-14

    Recent experiments on low-level irradiation during development raise questions relevant to ICRP Publication 26. Mice and monkeys were studied; the measured endpoint was the radiation-induced loss of female germ cells. Three issues are examined. The first is the numerical value of Q (quality factor) appropriate for low-energy beta rays. Comparisons of tritium with gamma radiation were made under conditions of chronic, low-level exposure, and the relative biological effectiveness (RBE) was found to approach 3. Its bearing on ICRP's recommendations concerning Q applicable to tritium is discussed. Second, female germ cells in squirrel monkeys before birth were discovered to be extraordinarily radiosensitive, more easily destroyed than those of mice. If this holds for other primates too, it has radiation-protection implications hitherto overlooked. Third, the contrast between massive germ-cell loss from chronic exposure in prenatal squirrel monkeys and reported radioresistance of oocytes to acute exposure in rhesus monkeys, unless due to species difference, suggests that during development protracted irradiation may be especially injurious. This also could have important radiation-protection implications and is under investigation. (ERB)

  16. Low dose irradiation reduces cancer mortality rates

    International Nuclear Information System (INIS)

    Luckey, T.D.

    2000-01-01

    . Increased production of many molecules (interleukins, interferons, leukotrienes, chemotactic agents, and mitogens) related to immunity are found in mice exposed to low dose irradiation (Lim, S.-Z., Biologic Effects of Low Level Exposures to Radiation and Related Agents, pp.15-16, 1993). Those plus many enzymes and cofactors are inter- and intra-cellular agents involved in gene expression, T-cell maturation, phagocytosis, signal transduction, antigen reception and antibody production. This basic science information has been utilized for cancer therapy in Japanese and United States clinics. With the usual radio-, chemo- and surgical therapy, the 10 year survival of non-Hodgkin's lymphoma was 59%; when this was augmented by low dose irradiation, survival was 80% (Sakamoto, K., ICONE-7 Abstracts, p 50-51, 1999). Low dose irradiation of the mid-section of the body was effective. This area includes many elements of the immune system: the spleen with its germinal centers and lymphoid follicles, the liver with its phagocytosing Kupffer cells, kidney phagocytes, and the lamina propria and Peyer's patches of the intestinal wall. Irradiation of either the head and chest or the groin-legs area was unresponsive. Chronic low dose irradiation redness premature cancer mortality 51%. Standards should be revised with health, not risks, as the goal. Safe supplementation with ionizing radiation would provide a new plateau of health for people and wealth for nations. (author)

  17. Effects of chronic low-dose radiation exposure and non-radiation factors on eye pathology in the Techa River Cohort

    International Nuclear Information System (INIS)

    Mikryukova, L.D.; Akleyev, A.V.

    2008-01-01

    Full text: As a result of the Mayak PA activities, radioactive wastes were discharged into the Techa River over the period 1949-1956. Data on eye pathology among Techa riverside residents chronically exposed to radiation (external and internal) have been collected and analyzed. The cohort which includes persons of the two genders born before 1950 gives one of the rare opportunities to assess the risk of late effects on human health associated with small-dose radiation exposure. Currently, the cohort numbers 29,749 individuals. In terms of ethnicity, 80 % of the cohort members are Slavs, and 20 % are Tartars and Bashkirs. The first study and analyses of eye pathology were conducted for this cohort during the period from 2001 through 2004. It was established that the cumulative rate of eye disease incidence increased with age and exposure dose. The relative risk value for development of ophthalmopathy among members of the study group was estimated taking into account the potential effects of gender, ethnicity and attained age. The relative risk value was 2.42 per 1 Gy of absorbed dose to soft tissues (95 % CI: 1.94; 3.03). With increase in attained age by 10 years an 8 % increase in the incidence of eye pathology was registered (p<0.001). The rate of eye disease incidence estimated for women was significantly higher than that for men (p<0.05 %). No significant differences were noted in the coefficient of eye disease incidence calculated for different ethnic groups. The structure of ophthalmopathy registered in residents of the Techa riverside villages chronically exposed in the dose range from 0 to 1,180 mGy is characterized by prevalence of cataracts, retinal and chorioid disorders. The rates of eye disease incidence were found to be dependent on external exposure dose; the highest doses were observed in the dose groups with doses 25 mGy. A statistically significant increase in the incidence of retinal angiosklerosis and a manifest tendency to develop cataracts was

  18. Impulsiveness, overactivity, and poorer sustained attention improve by chronic treatment with low doses of l-amphetamine in an animal model of Attention-Deficit/Hyperactivity Disorder (ADHD).

    Science.gov (United States)

    Sagvolden, Terje

    2011-03-30

    ADHD is currently defined as a cognitive/behavioral developmental disorder where all clinical criteria are behavioral. Overactivity, impulsiveness, and inattentiveness are presently regarded as the main clinical symptoms. There is no biological marker, but there is considerable evidence to suggest that ADHD behavior is associated with poor dopaminergic and noradrenergic modulation of neuronal circuits that involve the frontal lobes. The best validated animal model of ADHD, the Spontaneously Hypertensive Rat (SHR), shows pronounced overactivity, impulsiveness, and deficient sustained attention. The primary objective of the present research was to investigate behavioral effects of a range of doses of chronic l-amphetamine on ADHD-like symptoms in the SHR. The present study tested the behavioral effects of 0.75 and 2.2 mg l-amphetamine base/kg i.p. in male SHRs and their controls, the Wistar Kyoto rat (WKY). ADHD-like behavior was tested with a visual discrimination task measuring overactivity, impulsiveness and inattentiveness. The striking impulsiveness, overactivity, and poorer sustained attention seen during baseline conditions in the SHR were improved by chronic treatment with l-amphetamine. The dose-response curves were, however, different for the different behaviors. Most significantly, the 0.75 mg/kg dose of l-amphetamine improved sustained attention without reducing overactivity and impulsiveness. The 2.2 mg/kg dose improved sustained attention as well as reduced SHR overactivity and impulsiveness. The effects of l-amphetamine to reduce the behavioral symptoms of ADHD in the SHR were maintained over the 14 days of daily dosing with no evidence of tolerance developing.

  19. A Randomised, Controlled Comparison of Low-Dose Polyethylene Glycol 3350 plus Electrolytes with Ispaghula Husk in the Treatment of Adults with Chronic Functional Constipation.

    Science.gov (United States)

    Wang, Hui-Ji; Liang, Xiao-Mei; Yu, Zhong-Lin; Zhou, Li-Ya; Lin, San-Ren; Geraint, Mike

    2004-01-01

    To compare the efficacy and safety of polyethylene glycol (PEG) 3350 plus electrolytes (PEG+E; Movicol((R))) with that of ispaghula husk (psyllium; Konsyl((R))) in the treatment of constipation. Male or female adults with chronic functional constipation. This was a randomised, controlled, open-label, parallel-group trial. Study treatment was either PEG+E 13.8g/sachet dissolved in water twice daily or ispaghula husk 3.5g/sachet dissolved in water twice daily for a period of 2 weeks. Assessments were at baseline and after 1 and 2 weeks' therapy and by patient daily diary card. The primary outcome measures were weekly defaecation rate, stool consistency according to the Bristol Stool Form scale, time to first defaecation, and overall efficacy, which combined defaecation rate, stool consistency and difficulty on defaecation. Adverse effects were recorded and laboratory assessments were performed before and at the end of the treatment period. Sixty-three patients were randomised to each treatment group. Treatment was highly effective in 50/63 patients in the PEG+E group compared with 26/63 in the ispaghula husk group, and the overall efficacy rates were 92% and 73%, respectively (p = 0.005). PEG+E increased the mean weekly defaecation rate from 1.18 (SD 0.77) at baseline to 7.95 (SD 3.49) after 1 week and 8.48 (SD 3.55) after 2 weeks. In the ispaghula husk group the mean weekly defaecation rate increased from 1.33 (SD 0.68) at baseline to 5.33 (SD 2.81) after 1 week and to 5.71 (SD 2.49) after 2 weeks. The treatment differences for defaecation rates were all statistically significant (p PEG+E or ispaghula husk normalised stools in 55/63 (87.3%) and 42/63 (66.7%) of patients (p PEG 3350 plus electrolytes is more effective and more rapid in its onset of action than ispaghula husk, and is equally well tolerated.

  20. A pragmatic, phase III, multisite, double-blind, placebo-controlled, parallel-arm, dose increment randomised trial of regular, low-dose extended-release morphine for chronic breathlessness: Breathlessness, Exertion And Morphine Sulfate (BEAMS) study protocol.

    Science.gov (United States)

    Currow, David; Watts, Gareth John; Johnson, Miriam; McDonald, Christine F; Miners, John O; Somogyi, Andrew A; Denehy, Linda; McCaffrey, Nicola; Eckert, Danny J; McCloud, Philip; Louw, Sandra; Lam, Lawrence; Greene, Aine; Fazekas, Belinda; Clark, Katherine C; Fong, Kwun; Agar, Meera R; Joshi, Rohit; Kilbreath, Sharon; Ferreira, Diana; Ekström, Magnus

    2017-07-17

    Chronic breathlessness is highly prevalent and distressing to patients and families. No medication is registered for its symptomatic reduction. The strongest evidence is for regular, low-dose, extended- release (ER) oral morphine. A recent large phase III study suggests the subgroup most likely to benefit have chronic obstructive pulmonary disease (COPD) and modified Medical Research Council breathlessness scores of 3 or 4. This protocol is for an adequately powered, parallel-arm, placebo-controlled, multisite, factorial, block-randomised study evaluating regular ER morphine for chronic breathlessness in people with COPD. The primary question is what effect regular ER morphine has on worst breathlessness, measured daily on a 0-10 numerical rating scale. Uniquely, the coprimary outcome will use a FitBit to measure habitual physical activity. Secondary questions include safety and, whether upward titration after initial benefit delivers greater net symptom reduction. Substudies include longitudinal driving simulation, sleep, caregiver, health economic and pharmacogenetic studies. Seventeen centres will recruit 171 participants from respiratory and palliative care. The study has five phases including three randomisation phases to increasing doses of ER morphine. All participants will receive placebo or active laxatives as appropriate. Appropriate statistical analysis of primary and secondary outcomes will be used. Ethics approval has been obtained. Results of the study will be submitted for publication in peer-reviewed journals, findings presented at relevant conferences and potentially used to inform registration of ER morphine for chronic breathlessness. NCT02720822; Pre-results. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  1. Analysis of the Effect of Chronic and Low-Dose Radiation Exposure on Spermatogenic Cells of Male Large Japanese Field Mice ( Apodemus speciosus ) after the Fukushima Daiichi Nuclear Power Plant Accident.

    Science.gov (United States)

    Takino, Sachio; Yamashiro, Hideaki; Sugano, Yukou; Fujishima, Yohei; Nakata, Akifumi; Kasai, Kosuke; Hayashi, Gohei; Urushihara, Yusuke; Suzuki, Masatoshi; Shinoda, Hisashi; Miura, Tomisato; Fukumoto, Manabu

    2017-02-01

    In this study we analyzed the effect of chronic and low-dose-rate (LDR) radiation on spermatogenic cells of large Japanese field mice ( Apodemus speciosus ) after the Fukushima Daiichi Nuclear Power Plant (FNPP) accident. In March 2014, large Japanese field mice were collected from two sites located in, and one site adjacent to, the FNPP ex-evacuation zone: Tanashio, Murohara and Akogi, respectively. Testes from these animals were analyzed histologically. External dose rate from radiocesium (combined 134 Cs and 137 Cs) in these animals at the sampling sites exhibited 21 μGy/day in Tanashio, 304-365 μGy/day in Murohara and 407-447 μGy/day in Akogi. In the Akogi group, the numbers of spermatogenic cells and proliferating cell nuclear antigen (PCNA)-positive cells per seminiferous tubule were significantly higher compared to the Tanashio and Murohara groups, respectively. TUNEL-positive apoptotic cells tended to be detected at a lower level in the Murohara and Akogi groups compared to the Tanashio group. These results suggest that enhanced spermatogenesis occurred in large Japanese field mice living in and around the FNPP ex-evacuation zone. It remains to be elucidated whether this phenomenon, attributed to chronic exposure to LDR radiation, will benefit or adversely affect large Japanese field mice.

  2. Suppression of PTEN transcription by UVA

    Science.gov (United States)

    Zhao, Baozhong; Ming, Mei; He, Yu-Ying

    2012-01-01

    Although UVA has different physical and biological targets than UVB, the contribution of UVA to skin cancer susceptibility and its molecular basis remain largely unknown. Here we show that chronic UVA radiation suppresses PTEN expression at the mRNA level. Subchronic and acute UVA radiation also down-regulated PTEN in normal human epidermal keratinocytes, skin culture and mouse skin. At the molecular level, chronic UVA radiation decreased the transcriptional activity of the PTEN promoter in a methylation-independent manner, while it had no effect on the protein stability or mRNA stability of PTEN. In contrast, we found that UVA-induced activation of the Ras/ERK/AKT and NF-κB pathways plays an important role in UV-induced PTEN down-regulation. Inhibiting ERK or AKT increases PTEN expression. Our findings may provide unique insights into PTEN down-regulation as a critical component of UVA’s molecular impact during keratinocyte transformation. PMID:23129115

  3. Chronic Exposure to Rhodobacter Sphaeroides Extract Lycogen™ Prevents UVA-Induced Malondialdehyde Accumulation and Procollagen I Down-Regulation in Human Dermal Fibroblasts

    Science.gov (United States)

    Yang, Tsai-Hsiu; Lai, Ying-Hsiu; Lin, Tsuey-Pin; Liu, Wen-Sheng; Kuan, Li-Chun; Liu, Chia-Chyuan

    2014-01-01

    UVA contributes to the pathogenesis of skin aging by downregulation of procollagen I content and induction of matrix metalloproteinase (MMP)-associated responses. Application of antioxidants such as lycopene has been demonstrated as a convenient way to achieve protection against skin aging. Lycogen™, derived from the extracts of Rhodobacter sphaeroides, exerts several biological effects similar to that of lycopene whereas most of its anti-aging efficacy remains uncertain. In this study, we attempted to examine whether Lycogen™ could suppress malondialdehyde (MDA) accumulation and restore downregulated procollagen I expression induced by UVA exposure. In human dermal fibroblasts Hs68 cells, UVA repressed cell viability and decreased procollagen I protein content accompanied with the induction of MMP-1 and MDA accumulation. Remarkably, incubation with 50 μM Lycogen™ for 24 h ameliorated UVA-induced cell death and restored UVA-induced downregulation of procollagen in a dose-related manner. Lycogen™ treatment also prevented the UVA-induced MMP-1 upregulation and intracellular MDA generation in Hs68 cells. Activation of NFκB levels, one of the downstream events induced by UVA irradiation and MMP-1 induction, were also prevented by Lycogen™ administration. Taken together, our findings demonstrate that Lycogen™ may be an alternative agent that prevents UVA-induced skin aging and could be used in cosmetic and pharmaceutical applications. PMID:24463291

  4. 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

  5. Human circulating ribosomal DNA content significantly increases while circulating satellite III (1q12) content decreases under chronic occupational exposure to low-dose gamma- neutron and tritium beta-radiation

    International Nuclear Information System (INIS)

    Korzeneva, Inna B.; Kostuyk, Svetlana V.; Ershova, Elizaveta S.; Skorodumova, Elena N.; Zhuravleva, Veronika F.; Pankratova, Galina V.; Volkova, Irina V.; Stepanova, Elena V.; Porokhovnik, Lev N.; Veiko, Natalia N.

    2016-01-01

    Highlights: • A transcribed region of human ribosomal repeat is resistant to double-strand breaks in the environment of a raised endonuclease activity. • Hybridization-based techniques are preferable for the analysis of damaged and/or oxidized genomic fragments, rather than the qRT-PCR method. • A chronic exposure to the low-dose IR induces an elevation of the rDNA content in the human circulating cfDNA as compared to cellular DNA. • An exposure to IR entails a decrease of the level of the human circulating satellite III (1q12) as compared to cellular DNA (RsatIII index). • The RrDNA/RsatIII ratio is a potential marker of a chronic IR individual exposure. - Abstract: A single exposure to ionizing radiation (IR) results in an elevated cell-free DNA (cfDNA) content in the blood plasma. In this case, the cfDNA concentration can be a marker of the cell death in the organism. However, a chronic exposure to a low-dose IR enhances both the endonuclease activity and titer of antibodies to DNA in blood plasma, resulting in a decrease of the total concentration of circulating cfDNA in exposed people. In this case, the total cfDNA concentration should not be considered as a marker of the cell death in an exposed body. We assumed that a pool of the cfDNA circulating in the exposed people contains DNA fragments, which are resistant to a double-strand break formation in the environment of the elevated plasma endonuclease activity, and can be accumulated in the blood plasma. In order to test this hypothesis, we studied the content of GC-rich sequences (69%GC) of the transcribed region of human ribosomal repeat (rDNA), as well as the content of AT-rich repeat (63%AT) of satellite III (1q12) in the cfDNA samples obtained from 285 individuals. We have found that a chronic exposure to gamma-neutron radiation (N = 88) and tritium β-radiation (N = 88) evokes an increase of the rDNA content (RrDNA index) and a decrease of the satellite III content (RsatIII index) in the

  6. Human circulating ribosomal DNA content significantly increases while circulating satellite III (1q12) content decreases under chronic occupational exposure to low-dose gamma- neutron and tritium beta-radiation

    Energy Technology Data Exchange (ETDEWEB)

    Korzeneva, Inna B., E-mail: inna.korzeneva@molgen.vniief.ru [Russian Federal Nuclear Center – All-Russian Research Institute of Experimental Physics (RFNC-VNIIEF) 607190 Sarov, 37 Mira ave., Nizhniy Novgorod Region (Russian Federation); Kostuyk, Svetlana V. [Research Centre for Medical Genetics, 115478 Moscow, 1 Moskvorechye str. (Russian Federation); Ershova, Elizaveta S. [Research Centre for Medical Genetics, 115478 Moscow, 1 Moskvorechye str. (Russian Federation); V. A. Negovsky Research Institute of General Reanimatology, Moscow, 107031 (Russian Federation); Skorodumova, Elena N.; Zhuravleva, Veronika F.; Pankratova, Galina V.; Volkova, Irina V.; Stepanova, Elena V. [Russian Federal Nuclear Center – All-Russian Research Institute of Experimental Physics (RFNC-VNIIEF) 607190 Sarov, 37 Mira ave., Nizhniy Novgorod Region (Russian Federation); Porokhovnik, Lev N. [Research Centre for Medical Genetics, 115478 Moscow, 1 Moskvorechye str. (Russian Federation); Veiko, Natalia N. [Research Centre for Medical Genetics, 115478 Moscow, 1 Moskvorechye str. (Russian Federation); V. A. Negovsky Research Institute of General Reanimatology, Moscow, 107031 (Russian Federation)

    2016-09-15

    Highlights: • A transcribed region of human ribosomal repeat is resistant to double-strand breaks in the environment of a raised endonuclease activity. • Hybridization-based techniques are preferable for the analysis of damaged and/or oxidized genomic fragments, rather than the qRT-PCR method. • A chronic exposure to the low-dose IR induces an elevation of the rDNA content in the human circulating cfDNA as compared to cellular DNA. • An exposure to IR entails a decrease of the level of the human circulating satellite III (1q12) as compared to cellular DNA (RsatIII index). • The RrDNA/RsatIII ratio is a potential marker of a chronic IR individual exposure. - Abstract: A single exposure to ionizing radiation (IR) results in an elevated cell-free DNA (cfDNA) content in the blood plasma. In this case, the cfDNA concentration can be a marker of the cell death in the organism. However, a chronic exposure to a low-dose IR enhances both the endonuclease activity and titer of antibodies to DNA in blood plasma, resulting in a decrease of the total concentration of circulating cfDNA in exposed people. In this case, the total cfDNA concentration should not be considered as a marker of the cell death in an exposed body. We assumed that a pool of the cfDNA circulating in the exposed people contains DNA fragments, which are resistant to a double-strand break formation in the environment of the elevated plasma endonuclease activity, and can be accumulated in the blood plasma. In order to test this hypothesis, we studied the content of GC-rich sequences (69%GC) of the transcribed region of human ribosomal repeat (rDNA), as well as the content of AT-rich repeat (63%AT) of satellite III (1q12) in the cfDNA samples obtained from 285 individuals. We have found that a chronic exposure to gamma-neutron radiation (N = 88) and tritium β-radiation (N = 88) evokes an increase of the rDNA content (RrDNA index) and a decrease of the satellite III content (RsatIII index) in the

  7. Dermal damage promoted by repeated low-level UV-A1 exposure despite tanning response in human skin.

    Science.gov (United States)

    Wang, Frank; Smith, Noah R; Tran, Bao Anh Patrick; Kang, Sewon; Voorhees, John J; Fisher, Gary J

    2014-04-01

    Solar UV irradiation causes photoaging, characterized by fragmentation and reduced production of type I collagen fibrils that provide strength to skin. Exposure to UV-B irradiation (280-320 nm) causes these changes by inducing matrix metalloproteinase 1 and suppressing type I collagen synthesis. The role of UV-A irradiation (320-400 nm) in promoting similar molecular alterations is less clear yet important to consider because it is 10 to 100 times more abundant in natural sunlight than UV-B irradiation and penetrates deeper into the dermis than UV-B irradiation. Most (approximately 75%) of solar UV-A irradiation is composed of UV-A1 irradiation (340-400 nm), which is also the primary component of tanning beds. To evaluate the effects of low levels of UV-A1 irradiation, as might be encountered in daily life, on expression of matrix metalloproteinase 1 and type I procollagen (the precursor of type I collagen). In vivo biochemical analyses were conducted after UV-A1 irradiation of normal human skin at an academic referral center. Participants included 22 healthy individuals without skin disease. Skin pigmentation was measured by a color meter (chromometer) under the L* variable (luminescence), which ranges from 0 (black) to 100 (white). Gene expression in skin samples was assessed by real-time polymerase chain reaction. Lightly pigmented human skin (L* >65) was exposed up to 4 times (1 exposure/d) to UV-A1 irradiation at a low dose (20 J/cm2), mimicking UV-A levels from strong sun exposure lasting approximately 2 hours. A single exposure to low-dose UV-A1 irradiation darkened skin slightly and did not alter matrix metalloproteinase 1 or type I procollagen gene expression. With repeated low-dose UV-A1 irradiation, skin darkened incrementally with each exposure. Despite this darkening, 2 or more exposures to low-dose UV-A1 irradiation significantly induced matrix metalloproteinase 1 gene expression, which increased progressively with successive exposures. Repeated UV-A1

  8. Human circulating ribosomal DNA content significantly increases while circulating satellite III (1q12) content decreases under chronic occupational exposure to low-dose gamma- neutron and tritium beta-radiation.

    Science.gov (United States)

    Korzeneva, Inna B; Kostuyk, Svetlana V; Ershova, Elizaveta S; Skorodumova, Elena N; Zhuravleva, Veronika F; Pankratova, Galina V; Volkova, Irina V; Stepanova, Elena V; Porokhovnik, Lev N; Veiko, Natalia N

    A single exposure to ionizing radiation (IR) results in an elevated cell-free DNA (cfDNA) content in the blood plasma. In this case, the cfDNA concentration can be a marker of the cell death in the organism. However, a chronic exposure to a low-dose IR enhances both the endonuclease activity and titer of antibodies to DNA in blood plasma, resulting in a decrease of the total concentration of circulating cfDNA in exposed people. In this case, the total cfDNA concentration should not be considered as a marker of the cell death in an exposed body. We assumed that a pool of the cfDNA circulating in the exposed people contains DNA fragments, which are resistant to a double-strand break formation in the environment of the elevated plasma endonuclease activity, and can be accumulated in the blood plasma. In order to test this hypothesis, we studied the content of GC-rich sequences (69%GC) of the transcribed region of human ribosomal repeat (rDNA), as well as the content of AT-rich repeat (63%AT) of satellite III (1q12) in the cfDNA samples obtained from 285 individuals. We have found that a chronic exposure to gamma-neutron radiation (N=88) and tritium β-radiation (N=88) evokes an increase of the rDNA content (RrDNA index) and a decrease of the satellite III content (RsatIII index) in the circulating cfDNA as compared with the cfDNA of non-exposed people (N=109). Such index that simultaneously displays both the increase of rDNA content and decrease of satellite III content in the cfDNA (RrDNA/RsatIII) can be recommended as a marker of chronic processes in the body that involve the elevated cell death rate and/or increased blood plasma endonuclease activity. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. 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

  10. 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

  11. Psoralen-UVA-treated psoriatic lesions

    International Nuclear Information System (INIS)

    Hashimoto, K.; Kohda, H.; Kumakiri, M.; Blender, S.L.; Willis, I.

    1978-01-01

    Psoralen-ultraviolet light (PUVA)-treated psoriatic lesions were studied for ultrastructural changes. In early stages of treatment, sunburn cells in the epidermis and bizarre giant cells in the dermis were more frequently observed. When clinical improvement was apparent, these changes had subsided. Dermal abnormality in long-term therapy consisted of a thick perivascular cost of amorphous substance. No abnormality was found in the epidermal keratinocytes in long-term therapy, except a clustering and giant cell formation of melanocytes, a heavy melanization of keratinocytes, and hyperkeratosis. Low-dose initiation and slow increment of both 8-methoxypsoralen and UVA is probably a reasonable regimen for benign dermatoses such as psoriasis because it will allow enough time for the skin to become more protected, while the therapeutic results are as satisfactory as in a high-dose schedule

  12. Chronic treatment of (R)-α-lipoic acid reduces blood glucose and lipid levels in high-fat diet and low-dose streptozotocin-induced metabolic syndrome and type 2 diabetes in Sprague-Dawley rats.

    Science.gov (United States)

    Ghelani, Hardik; Razmovski-Naumovski, Valentina; Nammi, Srinivas

    2017-06-01

    (R)- α -lipoic acid ( ALA ), an essential cofactor in mitochondrial respiration and a potential antioxidant, possesses a wide array of metabolic benefits including anti-obesity, glucose lowering, insulin-sensitizing, and lipid-lowering effects. In this study, the curative effects of ALA (100 mg/kg) on a spectrum of conditions related to metabolic syndrome and type 2 diabetes ( T2D ) were investigated in a high-fat diet (HFD)-fed and low-dose streptozotocin (STZ)-induced rat model of metabolic syndrome and T2D . The marked rise in the levels of glucose, triglycerides, total-cholesterol, LDL-cholesterol, and VLDL-cholesterol in the blood of HFD-fed and low-dose STZ-injected rats were significantly reduced by ALA treatment. Furthermore, ALA treatment significantly increased the serum HDL-cholesterol levels and tended to inhibit diabetes-induced weight reduction. Mathematical computational analysis revealed that ALA also significantly improved insulin sensitivity and reduced the risk of atherosclerotic lesions and coronary atherogenesis. This study provides scientific evidence to substantiate the use of ALA to mitigate the glucose and lipid abnormality in metabolic syndrome and T2D .

  13. 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

  14. 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

  15. 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

  16. 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.)

  17. 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.

  18. 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)

  19. 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

  20. 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

  1. 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

  2. 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)

  3. 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.’

  4. 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

  5. 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

  6. 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.

  7. 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)

  8. 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

  9. 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)

  10. 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

  11. UVA Causes Dual Inactivation of Cathepsin B and L Underlying Lysosomal Dysfunction in Human Dermal Fibroblasts

    Science.gov (United States)

    Lamore, Sarah D.; Wondrak, Georg T.

    2013-01-01

    Cutaneous exposure to chronic solar UVA-radiation is a causative factor in photocarcinogenesis and photoaging. Recently, we have identified the thiol-dependent cysteine-protease cathepsin B as a novel UVA-target undergoing photo-oxidative inactivation upstream of autophagic-lysosomal dysfunction in fibroblasts. In this study, we examined UVA effects on a wider range of cathepsins and explored the occurrence of UVA-induced cathepsin inactivation in other cultured skin cell types. In dermal fibroblasts, chronic exposure to non-cytotoxic doses of UVA caused pronounced inactivation of the lysosomal cysteine-proteases cathepsin B and L, effects not observed in primary keratinocytes and occurring only to a minor extent in primary melanocytes. In order to determine if UVA-induced lysosomal impairment requires single or dual inactivation of cathepsin B and/or L, we used a genetic approach (siRNA) to selectively downregulate enzymatic activity of these target cathepsins. Monitoring an established set of protein markers (including LAMP1, LC3-II, and p62) and cell ultrastructural changes detected by electron microscopy, we observed that only dual genetic antagonism (targeting both CTSB and CTSL expression) could mimic UVA-induced autophagic-lysosomal alterations, whereas single knockdown (targeting CTSB or CTSL only) did not display ‘UVA-mimetic’ effects failing to reproduce the UVA-induced phenotype. Taken together, our data demonstrate that chronic UVA inhibits both cathepsin B and L enzymatic activity and that dual inactivation of both enzymes is a causative factor underlying UVA-induced impairment of lysosomal function in dermal fibroblasts. PMID:23603447

  12. 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

  13. 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

  14. 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)

  15. 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

  16. 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

  17. 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)

  18. 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)

  19. 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

  20. 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.)

  1. 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

  2. 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...

  3. 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

  4. 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

  5. Influence of repetitive UVA stimulation on skin protection capacity and antioxidant efficacy.

    Science.gov (United States)

    Rohr, Mathias; Rieger, Ingrid; Jain, Anil; Schrader, Andreas

    2011-01-01

    Topically applied antioxidants (AOs) are widely used in cosmetic products - especially in day and sun care - to help reduce oxidative stress caused by exogenous influences such as ultraviolet (UV) radiation. Despite several advances in recent years, little is known about the duration of protective effects by application of topical AOs, AO protection capacity (APC) or the activation of an endogenous protection capacity (EPC). By measuring oxidative-stress-induced photon emission of human skin in vivo with the ICL-S method (induced chemiluminescence of human skin), the protective effect of daily AO treatment for 2 weeks was examined on 4 consecutive days after treatment. UVA-dose-independent effects were investigated by decay curve intersection point analysis. In addition, chemiluminescence signal integration was used to investigate the influence of different UVA doses for stimulation on the determined APC as well as the modulation of the EPC by repetitive UVA stimulation both forming the skin protection capacity (SPC). The SPC showed a strong dependency on the UVA dose used for stimulation. AO pretreatment was more effective against lower UVA doses. Over the course of 4 days, the AO-induced SPC did not change significantly for a given UVA dose. Analyzing the decay curve intersection point for 2 different UVA doses, however, revealed a decrease in SPC with time. In addition, we found that a repetitive UVA irradiation of 1 J/cm(2) caused a statistically significant protective effect against UVA irradiation by stimulation of endogenous mechanisms. Topically supplemented AOs provide a protective effect against oxidative stress for at least 3 days, supporting their widespread use in cosmetic products. Especially their interaction with cutaneous protective mechanisms should be investigated in more detail for maximal protection, as endogenous defense mechanisms are already triggered by 2 low-dose UVA irradiations within 24 h. In summary, the in vivo measurement of UVA

  6. 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.

  7. 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

  8. 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

  9. 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.)

  10. 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

  11. 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.

  12. 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

  13. 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

  14. 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.)

  15. 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

  16. 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

  17. Uva mecânica

    OpenAIRE

    Da Costa Neto, Wilson; Barreiro Elorza, Pilar

    2015-01-01

    A colheita da uva no Brasil ainda e feita de forma manual na maioria dos parrirais. Mas neste cenerio ja e possivel ver maquinas realizando a tarefa antes feita pelas maos dos trabalhadores, operacao que em outros paises ja possui uma taxa de mecanizacao maior

  18. UVA photoactivation of DNA containing halogenated thiopyrimidines induces cytotoxic DNA lesions

    Science.gov (United States)

    Brem, Reto; Zhang, Xiaohui; Xu, Yao-Zhong; Karran, Peter

    2015-01-01

    Photochemotherapy, the combination of a photosensitiser and ultraviolet (UV) or visible light, is an effective treatment for skin conditions including cancer. The high mutagenicity and non-selectivity of photochemotherapy regimes warrants the development of alternative approaches. We demonstrate that the thiopyrimidine nucleosides 5-bromo-4-thiodeoxyuridine (SBrdU) and 5-iodo-4-thiodeoxyuridine (SIdU) are incorporated into the DNA of cultured human and mouse cells where they synergistically sensitise killing by low doses of UVA radiation. The DNA halothiopyrimidine/UVA combinations induce DNA interstrand crosslinks, DNA-protein crosslinks, DNA strand breaks, nucleobase damage and lesions that resemble UV-induced pyrimidine(6-4)pyrimidone photoproducts. These are potentially lethal DNA lesions and cells defective in their repair are hypersensitive to killing by SBrdU/UVA and SIdU/UVA. DNA SIdU and SBrdU generate lethal DNA photodamage by partially distinct mechanisms that reflect the different photolabilities of their C–I and C–Br bonds. Although singlet oxygen is involved in photolesion formation, DNA SBrdU and SIdU photoactivation does not detectably increase DNA 8-oxoguanine levels. The absence of significant collateral damage to normal guanine suggests that UVA activation of DNA SIdU or SBrdU might offer a strategy to target hyperproliferative skin conditions that avoids the extensive formation of a known mutagenic DNA lesion. PMID:25747491

  19. 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

  20. 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.

  1. 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....

  2. 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....

  3. 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

  4. 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)

  5. 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)

  6. 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)

  7. Cyclobutane pyrimidine dimers are photosensitised by carprofen plus UVA in human HaCaT cells.

    Science.gov (United States)

    Robinson, K S; Traynor, N J; Moseley, H; Ferguson, J; Woods, J A

    2010-06-01

    Every year in the UK about 75,000 cases of non-melanoma skin cancer (NMSC) are registered, and about 9500 people are diagnosed with cutaneous melanoma (CM). The main risk factor for these cancers is exposure to sunlight. The effects of light on skin are wavelength dependent, with wavelengths in the UVB waveband (280-315 nm) being the most carcinogenic. UVB is directly absorbed by DNA, producing dimeric pyrimidine photoproducts including cyclobutane pyrimidine dimers (CPD) and pyrimidine (6-4) pyrimodone photoproducts (6-4PP). However UVA (315-400 nm) can also produce CPD, induce skin tumours in mice, and has been shown to be mutagenic in cell culture. Although the precise role of UVA in human skin cancer remains to be elucidated, it comprises the major portion of solar UV radiation, transmits through window glass and can be delivered in high doses from tanning lamps. Non-steroidal anti-inflammatory drugs (NSAIDs), in particular the 2-aryl propionic acid derivatives, are a well-documented group of photosensitising chemicals producing clinical phototoxic and photoallergic reactions. We have used carprofen, a model compound from this group to see if it could amplify the effects of UVA and contribute to the formation of CPD by UVA. Preliminary work has shown that carprofen combined with low doses of UVA (lambda(max): 365 nm; 5 J/cm(2)) can produce both strand breaks (SB) and CPD in human skin or blood cells. CPD were detected indirectly by both an immunofluorescence method and as T4 endonuclease V sensitive sites in the comet assay. These findings show that compounds other than fluoroquinolones and psoralen derivatives may contribute to CPD formation in skin cells in combination with UVA. Copyright 2010 Elsevier Ltd. All rights reserved.

  8. 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

  9. 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 ...

  10. 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

  11. 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

  12. 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)

  13. 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.

  14. 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)

  15. 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

  16. 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)

  17. 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)

  18. 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

  19. 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.

  20. 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.

  1. 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

  2. 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)

  3. 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

  4. 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)

  5. 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.

  6. 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.

  7. 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.

  8. 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)

  9. 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

  10. 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)

  11. 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.

  12. 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

  13. 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)

  14. Immunomodulatory Effects of Macrolide Antibiotics - Part 2 : Advantages and Disadvantages of Long-Term, Low-Dose Macrolide Therapy

    NARCIS (Netherlands)

    Altenburg, J.; de Graaff, C. S.; van der Werf, T. S.; Boersma, W. G.

    2011-01-01

    The available evidence for long-term, low-dose treatment with 14- and 15-membered ring macrolides in non-cystic fibrosis (CF) bronchiectasis, COPD, chronic sinusitis, and asthma is reviewed with special attention to possible adverse effects and the emergence of resistance during long-term macrolide

  15. Pre-irradiation at a low dose-rate blunted p53 response

    International Nuclear Information System (INIS)

    Takahashi, A.; Ohnishi, K.; Asakawa, I.; Tamamoto, T.; Yasumoto, J.; Yuki, K.; Ohnishi, T.; Tachibana, A.

    2003-01-01

    Full text: We have studied whether the p53-centered signal transduction pathway induced by acute radiation is interfered with chronic pre-irradiation at a low dose-rate in human cultured cells and whole body of mice. In squamous cell carcinoma cells, we found that a challenge irradiation with X-ray immediately after chronic irradiation resulted in lower levels of p53 than those observed after the challenge irradiation alone. In addition, the induction of p53-centered apoptosis and the accumulation of its related proteins after the challenge irradiation were strongly correlated with the above-mentioned phenomena. In mouse spleen, the induction of apoptosis and the accumulation of p53 and Bax were observed dose-dependently at 12 h after a challenge irradiation. In contrast, we found significant suppression of them induced by challenge irradiation at a high dose-rate when mice were pre-irradiated with chronic irradiation at a low dose-rate. These findings suggest that chronic pre-irradiation suppressed the p53 function through radiation-induced p53-dependent signal transduction processes. There are numerous papers about p53 functions in apoptosis, radiosensitivity, genomic instability and cancer incidence in cultured cells or animals. According to our data and other findings, since p53 can prevent carcinogenesis, pre-irradiation at a low dose-rate might enhance the predisposition to cancer. Therefore, it is possible that different maximal permissible dose equivalents for the public populations are appropriate. Furthermore, concerning health of human beings, studies of the adaptive responses to radiation are quite important, because the radiation response strongly depends on experience of prior exposure to radiation

  16. Influence of solar UVA on erythemal irradiances

    International Nuclear Information System (INIS)

    Parisi, A V; Turnbull, D J; Kimlin, M G

    2006-01-01

    Many materials in everyday use such as window glass in homes and offices, glass in sunrooms and greenhouses, vehicle glass and some brands of sunscreens act as a barrier to the shorter UVB wavelengths while transmitting some of the longer UVA wavelengths. This paper reports on the erythemal exposures due to the UVA waveband encountered over a 12-month period for a solar zenith angle (SZA) range of 4 0 to 80 0 and the resulting times required for an erythemal exposure of one standard erythemal dose (SED) due to the erythemal exposures to the UVA wavelengths. The minimum time for an exposure of one SED due to the UVA wavelengths in winter is approximately double that what it is in summer. The time period of 40 to 60 min was the most frequent length of time for an exposure of one SED with 60 to 80 min the next frequent length of time required for a one SED exposure

  17. Low-dose memantine attenuated morphine addictive behavior through its anti-inflammation and neurotrophic effects in rats.

    Science.gov (United States)

    Chen, Shiou-Lan; Tao, Pao-Luh; Chu, Chun-Hsien; Chen, Shih-Heng; Wu, Hsiang-En; Tseng, Leon F; Hong, Jau-Shyong; Lu, Ru-Band

    2012-06-01

    Opioid abuse and dependency are international problems. Studies have shown that neuronal inflammation and degeneration might be related to the development of opioid addiction. Thus, using neuroprotective agents might be beneficial for treating opioid addiction. Memantine, an Alzheimer's disease medication, has neuroprotective effects in vitro and in vivo. In this study, we evaluated whether a low dose of memantine prevents opioid-induced drug-seeking behavior in rats and analyzed its mechanism. A conditioned-place-preference test was used to investigate the morphine-induced drug-seeking behaviors in rats. We found that a low-dose (0.2-1 mg/kg) of subcutaneous memantine significantly attenuated the chronic morphine-induced place-preference in rats. To clarify the effects of chronic morphine and low-dose memantine, serum and brain levels of cytokines and brain-derived neurotrophic factor (BDNF) were measured. After 6 days of morphine treatment, cytokine (IL-1β, IL-6) levels had significantly increased in serum; IL-1β and IL-6 mRNA levels had significantly increased in the nucleus accumbens and medial prefrontal cortex, both addiction-related brain areas; and BDNF levels had significantly decreased, both in serum and in addiction-related brain areas. Pretreatment with low-dose memantine significantly attenuated chronic morphine-induced increases in serum and brain cytokines. Low-dose memantine also significantly potentiated serum and brain BDNF levels. We hypothesize that neuronal inflammation and BDNF downregulation are related to the progression of opioid addiction. We hypothesize that the mechanism low-dose memantine uses to attenuate morphine-induced addiction behavior is its anti-inflammatory and neurotrophic effects.

  18. 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

  19. 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

  20. 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 ...

  1. 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...

  2. 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

  3. 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

  4. 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.)

  5. 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...

  6. 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.

  7. 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

  8. 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)

  9. 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

  10. 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

  11. 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.

  12. 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)

  13. Detecting airway remodeling in COPD and emphysema using low-dose CT imaging

    Science.gov (United States)

    Rudyanto, R.; Ceresa, M.; Muñoz-Barrutia, A.; Ortiz-de-Solorzano, C.

    2012-03-01

    In this study, we quantitatively characterize lung airway remodeling caused by smoking-related emphysema and Chronic Obstructive Pulmonary Disease (COPD), in low-dose CT scans. To that end, we established three groups of individuals: subjects with COPD (n=35), subjects with emphysema (n=38) and healthy smokers (n=28). All individuals underwent a low-dose CT scan, and the images were analyzed as described next. First the lung airways were segmented using a fast marching method and labeled according to its generation. Along each airway segment, cross-section images were resampled orthogonal to the airway axis. Next 128 rays were cast from the center of the airway lumen in each crosssection slice. Finally, we used an integral-based method, to measure lumen radius, wall thickness, mean wall percentage and mean peak wall attenuation on every cast ray. Our analysis shows that both the mean global wall thickness and the lumen radius of the airways of both COPD and emphysema groups were significantly different from those of the healthy group. In addition, the wall thickness change starts at the 3rd airway generation in the COPD patients compared with emphysema patients, who display the first significant changes starting in the 2nd generation. In conclusion, it is shown that airway remodeling happens in individuals suffering from either COPD or emphysema, with some local difference between both groups, and that we are able to detect and accurately quantify this process using images of low-dose CT scans.

  14. Protective effect of low dose caffeine on psychological stress and cognitive function.

    Science.gov (United States)

    Çakır, Özgür Kasımay; Ellek, Nurfitnat; Salehin, Nabila; Hamamcı, Rabia; Keleş, Hülya; Kayalı, Damla Gökçeoğlu; Akakın, Dilek; Yüksel, Meral; Özbeyli, Dilek

    2017-01-01

    Caffeine is an adrenergic antagonist that enhances neuronal activity. Psychological stress depresses cognitive function. To investigate the effects of acute and chronic low dose caffeine on anxiety-like behavior and cognitive functions of acute or chronic psychological stressed rats. Acute or chronic caffeine (3mg/kg) was administered to male Sprague Dawley rats (200-250g, n=42) before acute (cat odor) and chronic variable psychological stress (restraint overcrowding stress, elevated plus maze, cat odor, forced swimming) induction. Anxiety and cognitive functions were evaluated by hole-board and object recognition tests. The brain glutathione and malondialdehyde assays, myeloperoxidase, nitric oxide (NO), superoxide dismutase (SOD), luminol and lucigenin activity and histological examination were done. ANOVA and Student's t-test were used for statistical analysis. The depressed cognitive function with chronic stress exposure and the increased anxiety-like behavior with both stress inductions were improved via both caffeine applications (pcaffeine pretreatments in chronic stressed rats, and chronic caffeine in acute stressed ones reduced the elevated myeloperoxidase activities (pcaffeine (pcaffeine (pcaffeine decreased SOD activity (pcaffeine. The increased anxiety-like behavior and depleted cognitive functions under stress conditions were improved with both acute and predominantly chronic caffeine pretreatments by decreasing oxidative damage parameters. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. 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)

  16. Impacts of low doses of pesticide mixtures on liver cell defence systems

    OpenAIRE

    Zucchini-Pascal, Nathalie; Dupont, Gwendoline; Razpotnik, Andrej; Fouche, Edwin; De Sousa, Georges; Rahmani, Roger

    2012-01-01

    Low amounts of residual pesticides are present in the environment, often as mixtures of chemicals which contaminate drinking water and food, being a source of chronic exposure for humans and a growing matter of concern in public health policy. Despite of the needs and growing investigation, little is known about the impact of low doses and mixtures of these chemicals on human health. The purpose of this study was to enlighten if modifications of liver cell metabolic- and/or defence-related ca...

  17. 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

  18. 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

  19. 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.

  20. 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

  1. 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

  2. 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

  3. 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.

  4. 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)

  5. 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)

  6. 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)

  7. 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)

  8. 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.

  9. 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)

  10. 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)

  11. 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

  12. 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.)

  13. 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)

  14. 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.

  15. 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.)

  16. 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)

  17. 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

  18. 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)

  19. 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.

  20. 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 (

  1. 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)

  2. 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)

  3. 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

  4. 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.

  5. 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

  6. 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

  7. 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)

  8. 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.

  9. UVA1 a promising approach for scleroderma

    Science.gov (United States)

    Keyal, Uma; Bhatta, Anil Kumar; Wang, Xiu Li

    2017-01-01

    Scleroderma is a complex connective tissue disease characterized by fibrosis, vasculopathy, and immune system dysfunction. The heterogeneity of disease presentation and poorly understood etiology has made the management of scleroderma difficult. The available treatment options like immunosuppressive agents are associated with potentially hazardous side effects and physiotherapy, which to a certain degree helps to minimize the loss of function in digits and limbs, has only limited success. Also, studies investigating antifibrotic therapies have failed to report any significant improvement. Hence, there is currently no effective therapy for scleroderma. Recently, phototherapy has been extensively studied and found to be effective in treating scleroderma. Initially psoralen + ultraviolet A (PUVA) significantly enriched the therapeutic panel, but more recently ultraviolet A1 (UVA1) is seen to replace PUVA therapy. This might be because of UVA1 therapy being free of side effects seen with psoralens such as nausea, vomiting or photokeratitis. In addition, UVA1 is seen to lower risk of phototoxic reactions with deeper penetration of radiation. The present review will put some light on the use of UVA1 for treating cutaneous lesion in scleroderma and we aim to find the most benefitted group of patients and most effective dose of UVA1 for different types of scleroderma. PMID:28979701

  10. Lifestyle, sun worshipping and sun tanning - what about UV-A sun beds. Livsstil, soling og bruning - hva med UV-A solarier

    Energy Technology Data Exchange (ETDEWEB)

    Thune, P. (Ullevaal Sykehus, Oslo (Norway))

    1991-06-01

    This article considers the effects of ultraviolet (UV) light from the sun and UV-A sun beds on the skin. Sun worshipping and sun therapy has been en vogue for centuries, but in another way than used today. A changing lifestyle has led to an increase of various skin diseases, including skin cancer. Short wave UV-light (UV-B) in particular has been blamed for inducing not only erythema and pigmentation but also more chronic skin lesions. Long wave UV-light (UV-A) has been shown to be the cause of similar changes to the skin but the pigmentation is of another quality and affords less protection against the harmful effects of UV-B. A concept of sun reactive skin typing has been created. This is based on self-reported responses to an initial exposure to sun as regards tanning ability and erythema reaction. These two factors have certain practical consequences, not only for UV-phototherapy but also for a person's risk of developing skin cancer. Recently, several research groups and dermatologists have discouraged extensive use of UV-A sun beds because of side effects of varying degrees of seriousness. The possible implications of these side effects for the organism are not fully elucidated and may be more profound than known today. The British Photodermatology Group has issued more stringent rules for persons who, despite advice to the contrary, still wish to use UV-A sun beds. 14 refs., 1 tab.

  11. Lifestyle, sun worshipping and sun tanning - what about UV-A sun beds. Livsstil, soling og bruning - hva med UV-A solarier

    Energy Technology Data Exchange (ETDEWEB)

    Thune, P [Ullevaal Sykehus, Oslo (Norway)

    1991-06-01

    This article considers the effects of ultraviolet (UV) light from the sun and UV-A sun beds on the skin. Sun worshipping and sun therapy has been en vogue for centuries, but in another way than used today. A changing lifestyle has led to an increase of various skin diseases, including skin cancer. Short wave UV-light (UV-B) in particular has been blamed for inducing not only erythema and pigmentation but also more chronic skin lesions. Long wave UV-light (UV-A) has been shown to be the cause of similar changes to the skin but the pigmentation is of another quality and affords less protection against the harmful effects of UV-B. A concept of sun reactive skin typing has been created. This is based on self-reported responses to an initial exposure to sun as regards tanning ability and erythema reaction. These two factors have certain practical consequences, not only for UV-phototherapy but also for a person's risk of developing skin cancer. Recently, several research groups and dermatologists have discouraged extensive use of UV-A sun beds because of side effects of varying degrees of seriousness. The possible implications of these side effects for the organism are not fully elucidated and may be more profound than known today. The British Photodermatology Group has issued more stringent rules for persons who, despite advice to the contrary, still wish to use UV-A sun beds. 14 refs., 1 tab.

  12. 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

  13. 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

  14. Biological effects of low-dose radiation on human population living in high-background radiation areas of Kerala coast

    International Nuclear Information System (INIS)

    Das, Birajalaxmi

    2016-01-01

    High-level natural radiation areas (HLNRA) of Kerala coast is densely populated and known for its wide variation in background radiation dose levels due to uneven distribution of monazite in the beach sand. The background radiation dose varies from 1 to 45 mGv/y. The areas with >1.5mGy/y is considered as HLNRA. Human population inhabiting in this area are exposed to low-dose chronic radiation since generations. Hence, this population provides an ideal situation to study dose response and adaptive response, if any, due to natural chronic low-dose exposure. It has been investigated extensively to study the biological and health effects of long-term low-dose/low-dose radiation exposure. So far over 150, 000 newborns monitored from hospital-based study did not reveal any significant difference in the incidence of any of the malformations and stillbirth between HLNRA and adjacent control areas. A case-control study on cleft lip/palate and mental retardation did not show any association with background radiation dose. Cytogenetic investigation of over 27,000 newborns did not show any significant increase in the frequency of chromosome aberrations and karyotype anomalies. DNA damage endpoints, such as micronuclei, telomere length and DNA strand breaks, did not reveal any significant difference between control and exposed population. Studies on DNA damage and repair revealed efficient repair of DNA strand breaks in HLNRA individuals. Molecular studies using high throughput microarray analysis indicated a large number of genes involved in various molecular and cellular pathways. Indications of in vivo radioadaptive response due to natural chronic low-dose exposure in this population have important implications to human health. (author)

  15. UVA Irradiation Enhances Brusatol-Mediated Inhibition of Melanoma Growth by Downregulation of the Nrf2-Mediated Antioxidant Response

    Science.gov (United States)

    Wang, Mei; Shi, Guangwei; Bian, Chunxiang; Nisar, Muhammad Farrukh; Guo, Yingying; Wu, Yan; Li, Wei; Huang, Xiao; Jiang, Xuemei; Bartsch, Jörg W.

    2018-01-01

    Brusatol (BR) is a potent inhibitor of Nrf2, a transcription factor that is highly expressed in cancer tissues and confers chemoresistance. UVA-generated reactive oxygen species (ROS) can damage both normal and cancer cells and may be of potential use in phototherapy. In order to provide an alternative method to treat the aggressive melanoma, we sought to investigate whether low-dose UVA with BR is more effective in eliminating melanoma cells than the respective single treatments. We found that BR combined with UVA led to inhibition of A375 melanoma cell proliferation by cell cycle arrest in the G1 phase and triggers cell apoptosis. Furthermore, inhibition of Nrf2 expression attenuated colony formation and tumor development from A375 cells in heterotopic mouse models. In addition, cotreatment of UVA and BR partially suppressed Nrf2 and its downstream target genes such as HO-1 along with the PI3K/AKT pathway. We propose that cotreatment increased ROS-induced cell cycle arrest and cellular apoptosis and inhibits melanoma growth by regulating the AKT-Nrf2 pathway in A375 cells which offers a possible therapeutic intervention strategy for the treatment of human melanoma. PMID:29670684

  16. 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.

  17. [Riboflavin UVA crosslinking in progressive keratoconus].

    Science.gov (United States)

    Maier, P; Reinhard, T

    2017-06-01

    In patients with keratoconus, a progressive, ectatic disease of the cornea, the shape of the cornea is continuously changing leading to a reduction in visual acuity by progressive myopia and more and more (irregular) astigmatism. The symptomatic treatment consists of the prescription of glasses or special gas-permeable rigid contact lenses. Corneal tomography is generally used for diagnosis. After initial diagnosis of keratoconus, regular tomographic follow-ups should be performed. If clinically significant progression is found and confirmed by repeated measurements, riboflavin UVA collagen crosslinking should be offered to the patients. The aim of riboflavin UVA collagen crosslinking is to halt the progression of the disease to avoid further complications. The therapeutic principle is a combined effect of the photosensitizer riboflavin and UVA light. This stiffening effect of the corneal tissue halts the progression of keratoconus. The efficacy of this treatment has been demonstrated in various randomized, controlled trials.

  18. Effect of low-dose ionizing radiation on luminous marine bacteria: radiation hormesis and toxicity.

    Science.gov (United States)

    Kudryasheva, N S; Rozhko, T V

    2015-04-01

    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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. New applications of UVA-1 cold light therapy

    NARCIS (Netherlands)

    Polderman, Marloes Christina Abichael

    2006-01-01

    UVA 1 therapy is a relatively new form of light therapy for atopic dermatitis. We describe that after 4 weeks of UVA-1 patients were better capable to maintain clinical improvement than after 3 weeks of therapy. Furthermore, UVA 1 therapy proved to be better than placebo therapy in patients with

  20. 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.)

  1. 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.)

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. 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)

  7. 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

  8. 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)

  9. 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

  10. 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

  11. Suppressing effect of low-dose ionizing radiation on incidence of type I diabetes of NOD mice

    International Nuclear Information System (INIS)

    Nomura, T.; Makino, N.; Oda, T.; Sakai, K.

    2002-01-01

    In the present study we examined the effects of 0.5 Gy of ionizing radiation, given acutely or chronically, on the incidence of type I diabetes in non-obese diabetic mice was examined. NOD mice are characterized by a progressive loss of insulin-producing cells in the pancreas by autoimmune mechanisms. The results suggest that the suppressive effects on the onset of he diabetes by the low dose irradiation are explain by the induction of the antioxidative activity

  12. 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)

  13. 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

  14. 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)

  15. 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)

  16. 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

  17. Low-Dose Ribavirin Treatments Attenuate Neuroinflammatory Activation of BV-2 Cells by Interfering with Inducible Nitric Oxide Synthase

    Directory of Open Access Journals (Sweden)

    Iva Bozic

    2015-01-01

    Full Text Available Microglia play a key role in defending central nervous system from various internal and external threats. However, their excessive and/or chronic activation is associated with deleterious effects in a variety of neurodegenerative diseases. Previously, we have shown that ribavirin when applied in clinically relevant dosage (10 μM modulates activated microglia in complex fashion inducing both anti- and proinflammatory effects, simultaneously causing cytotoxicity. Here, we examined potential of low-dose ribavirin (0.1 and 1 μM to modulate activated BV-2 microglia. Morphological and functional activation of BV-2 cells was achieved with lipopolysaccharide (LPS stimulation. Our results demonstrated that low-dose ribavirin did not induce cell death, while 10 μM ribavirin promoted LPS induced apoptosis. We determined that 1 μM ribavirin was equally efficient in deactivation of LPS induced morphological changes as 10 μM ribavirin treatment. Ribavirin showed halfway success in reducing markers of functional activation of microglia. Namely, none of the doses had effect on LPS triggered production of proinflammatory cytokine tumor necrosis factor alpha. On the other hand, low-dose ribavirin proved its effectiveness in reduction of another inflammatory mediator, nitric oxide, by inhibiting inducible form of nitric oxide synthase. Our results imply that low-dose ribavirin may alleviate nitrosative stress during neuroinflammation.

  18. Low-Dose Ribavirin Treatments Attenuate Neuroinflammatory Activation of BV-2 Cells by Interfering with Inducible Nitric Oxide Synthase

    Science.gov (United States)

    Bozic, Iva; Savic, Danijela; Jovanovic, Marija; Bjelobaba, Ivana; Laketa, Danijela; Nedeljkovic, Nadezda; Stojiljkovic, Mirjana; Pekovic, Sanja; Lavrnja, Irena

    2015-01-01

    Microglia play a key role in defending central nervous system from various internal and external threats. However, their excessive and/or chronic activation is associated with deleterious effects in a variety of neurodegenerative diseases. Previously, we have shown that ribavirin when applied in clinically relevant dosage (10 μM) modulates activated microglia in complex fashion inducing both anti- and proinflammatory effects, simultaneously causing cytotoxicity. Here, we examined potential of low-dose ribavirin (0.1 and 1 μM) to modulate activated BV-2 microglia. Morphological and functional activation of BV-2 cells was achieved with lipopolysaccharide (LPS) stimulation. Our results demonstrated that low-dose ribavirin did not induce cell death, while 10 μM ribavirin promoted LPS induced apoptosis. We determined that 1 μM ribavirin was equally efficient in deactivation of LPS induced morphological changes as 10 μM ribavirin treatment. Ribavirin showed halfway success in reducing markers of functional activation of microglia. Namely, none of the doses had effect on LPS triggered production of proinflammatory cytokine tumor necrosis factor alpha. On the other hand, low-dose ribavirin proved its effectiveness in reduction of another inflammatory mediator, nitric oxide, by inhibiting inducible form of nitric oxide synthase. Our results imply that low-dose ribavirin may alleviate nitrosative stress during neuroinflammation. PMID:26413464

  19. Scientific conception on mechanisms of calcium homeostasis disorders under low dose effect of ionizing radiation

    International Nuclear Information System (INIS)

    Abylaev, Zh.A.; Dospolova, Zh.G.

    1997-01-01

    Scientific conception of probable consequences of calcium homeostasis disorders in personals, exposed to low dose effect of ionizing radiation has been developed. Principle positions of the conception is that pathologic processes development have different ways of conducting. During predominance of low doses of external gamma-radiation there is leading pathologic mechanism (mechanism 1) of disorder neuroendocrine regulation of both the calcium and the phosphor. In this case sicks have disorders of both the vegetative tonus and the endocrine status. Under internal irradiation (mechanism 2) there is disfunction of organs and systems (bore changes and disorders of hormone status). These changes are considered as consequence of negative action on organism of incorporated long-living radionuclides. Radio-toxic factors action (mechanism 3) provokes the excess of hormones, which acting on bone tissue and could be cause of steroid osteoporosis. Influence of chronic stress factor (mechanism 4) enlarges and burden action on organism of low radiation doses. It is emphasized, that decisive role in development of pathologic processes has mechanism of disturbance of neuroendocrine regulation of calcium exchange

  20. Facility for gamma irradiations of cultured cells at low dose rates: design, physical characteristics and functioning

    International Nuclear Information System (INIS)

    Esposito, Giuseppe; Anello, Pasquale; Pecchia, Ilaria; Tabocchini, Maria Antonella; Campa, Alessandro

    2016-01-01

    We describe a low dose/dose rate gamma irradiation facility (called LIBIS) for in vitro biological systems, for the exposure, inside a CO_2 cell culture incubator, of cells at a dose rate ranging from few μGy/h to some tens of mGy/h. Three different "1"3"7Cs sources are used, depending on the desired dose rate. The sample is irradiated with a gamma ray beam with a dose rate uniformity of at least 92% and a percentage of primary 662 keV photons greater than 80%. LIBIS complies with high safety standards. - Highlights: • A gamma irradiation facility for chronic exposures of cells was set up at the Istituto Superiore di Sanità. • The dose rate uniformity and the percentage of primary 662 keV photons on the sample are greater than 92% and 80%, respectively. • The GEANT4 code was used to design the facility. • Good agreement between simulation and experimental dose rate measurements has been obtained. • The facility will allow to safely investigate different issues about low dose rate effects on cultured cells.

  1. Multilevel mechanisms of stimulatory effect of low dose radiation on immunity

    International Nuclear Information System (INIS)

    Shu-Zeng Liu

    1992-01-01

    Attention is paid to the effects of low level ionizing radiation on humans. The conference is devoted to low dose radiation and defense mechanisms of the body. Due to the importance of the immune system in body resistance, special attention has been given to host defense mechanisms following exposure to different doses of ionizing radiation. The immune system has long been known to be highly sensitive to moderate to high doses of ionizing radiation with immuno-depression as one of the most important causes of death in acute radiation syndrome. However, the dose-effect relationship of immune functions has been found to be quite different in the low dose range, especially with doses within 0.1 Gy. With doses above 0.5 Gy most immunologic parameters show a dose dependent depression. With doses between 0.1-0.5 Gy there may be no definite changes in immune functions. Doses within 0.1 Gy, given in single or chronic exposures, have been found to stimulate many immune responses. (author). 16 refs., 2 figs., 7 tabs

  2. Immunomodulatory Properties and Molecular Effects in Inflammatory Diseases of Low-Dose X-Irradiation

    International Nuclear Information System (INIS)

    Rödel, Franz; Frey, Benjamin; Manda, Katrin; Hildebrandt, Guido; Hehlgans, Stephanie; Keilholz, Ludwig; Seegenschmiedt, M. Heinrich; Gaipl, Udo S.; Rödel, Claus

    2012-01-01

    Inflammatory diseases are the result of complex and pathologically unbalanced multicellular interactions. For decades, low-dose X-irradiation therapy (LD-RT) has been clinically documented to exert an anti-inflammatory effect on benign diseases and chronic degenerative disorders. By contrast, experimental studies to confirm the effectiveness and to reveal underlying cellular and molecular mechanisms are still at their early stages. During the last decade, however, the modulation of a multitude of immunological processes by LD-RT has been explored in vitro and in vivo. These include leukocyte/endothelial cell adhesion, adhesion molecule and cytokine/chemokine expression, apoptosis induction, and mononuclear/polymorphonuclear cell metabolism and activity. Interestingly, these mechanisms display comparable dose dependences and dose-effect relationships with a maximum effect in the range between 0.3 and 0.7 Gy, already empirically identified to be most effective in the clinical routine. This review summarizes data and models exploring the mechanisms underlying the immunomodulatory properties of LD-RT that may serve as a prerequisite for further systematic analyses to optimize low-dose irradiation procedures in future clinical practice.

  3. Immunomodulatory Properties and Molecular Effects in Inflammatory Diseases of Low-Dose X-Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Rödel, Franz [Department of Radiotherapy and Oncology, University Hospital of Frankfurt, Johann Wolfgang-Goethe Universität, Frankfurt am Main (Germany); Frey, Benjamin [Department of Radiation Oncology, University Hospital Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen (Germany); Manda, Katrin; Hildebrandt, Guido [Department of Radiotherapy and Radiation Oncology, University of Rostock, Rostock (Germany); Hehlgans, Stephanie [Department of Radiotherapy and Oncology, University Hospital of Frankfurt, Johann Wolfgang-Goethe Universität, Frankfurt am Main (Germany); Keilholz, Ludwig [Department of Radiotherapy, Clinical Center Bayreuth, Bayreuth (Germany); Seegenschmiedt, M. Heinrich [Strahlenzentrum Hamburg Medizinisches Versorgungszentrum, Hamburg (Germany); Gaipl, Udo S. [Department of Radiation Oncology, University Hospital Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen (Germany); Rödel, Claus, E-mail: franz.roedel@kgu.de [Department of Radiotherapy and Oncology, University Hospital of Frankfurt, Johann Wolfgang-Goethe Universität, Frankfurt am Main (Germany)

    2012-09-25

    Inflammatory diseases are the result of complex and pathologically unbalanced multicellular interactions. For decades, low-dose X-irradiation therapy (LD-RT) has been clinically documented to exert an anti-inflammatory effect on benign diseases and chronic degenerative disorders. By contrast, experimental studies to confirm the effectiveness and to reveal underlying cellular and molecular mechanisms are still at their early stages. During the last decade, however, the modulation of a multitude of immunological processes by LD-RT has been explored in vitro and in vivo. These include leukocyte/endothelial cell adhesion, adhesion molecule and cytokine/chemokine expression, apoptosis induction, and mononuclear/polymorphonuclear cell metabolism and activity. Interestingly, these mechanisms display comparable dose dependences and dose-effect relationships with a maximum effect in the range between 0.3 and 0.7 Gy, already empirically identified to be most effective in the clinical routine. This review summarizes data and models exploring the mechanisms underlying the immunomodulatory properties of LD-RT that may serve as a prerequisite for further systematic analyses to optimize low-dose irradiation procedures in future clinical practice.

  4. Bolus versus continuous low dose of enalaprilat in congestive heart failure with acute refractory decompensation.

    Science.gov (United States)

    Podbregar, M; Voga, G; Horvat, M; Zuran, I; Krivec, B; Skale, R; Pareznik, R

    1999-01-01

    The first dose of angiotensin-converting enzyme (ACE) inhibitors may trigger a considerable fall of blood pressure in chronic heart failure. The response may be dose-related. To determine hemodynamic and systemic oxygenation effects of low-dose enalaprilat, we administered intravenous enalaprilat (0.004 mg/kg) as bolus (group B) or continuous 1-hour infusion (group C) in 20 patients with congestive heart failure due to ischemic heart disease with acute decompensation refractory to inotropic, vasodilator and diuretic therapy. Hemodynamic and systemic oxygenation variables were recorded at baseline (+0 min), +30, +60, +120, +180, and +360 min after the start of intervention. Mean arterial pressure (MAP) (p < 0. 001), mean pulmonary artery pressure (MPAP) (p < 0.001), pulmonary artery occlusion pressure (PAOP) (p < 0.001), oxygen extraction ratio (ER) (p < 0.026) decreased regardless of enalaprilat application. Compared to group B, there was in group C prolonged decrease of MAP, MPAP, PAOP, ER and increase of pulmonary artery oxyhemoglobin saturation in regard to baseline values. Cardiac index, heart rate, central venous pressure and oxygen consumption index did not change. A low dose of intravenous enalaprilat (0.004 mg/kg) can be used to safely improve hemodynamics and systemic oxygenation in congestive heart failure due to ischemic heart disease with acute refractory decompensation.

  5. Studies on chromosome aberrations induced in human lymphocytes by very low-dose exposure to tritium

    International Nuclear Information System (INIS)

    Hori, T.; Moriya, Junko; Nakai, Sayaka

    1978-01-01

    Assessment of potential hazard from environmental tritium to man becomes very important with increasing the development of nuclear-power industry. However, little data are available as to the determination on the genetic effect of tritium especially at the low levels. The object of the present study is to obtain quantitative data for chromosome aberrations in human lymphocytes, as an indicator for genetic risk estimation, induced by tritium at very low dose levels. Leukocyte cultures of human peripheral blood were chronically exposed for 48h to tritiated water and 3 H-thymidine using a wide range of tritium doses, and aberrations in lymphocyte chromosomes at the first metaphases were examined. In the experimental conditions, the types of aberrations induced by radiation emitted from both tritiated water and 3 H-thymidine were mostly chromatid types, such as chromatid gaps and deletions. The dose-response relations for chromatid breaks per cell exhibited unusual dose-dependency in both cases. It was demonstrated that at higher dose range the yields of chromatid breaks increased linearly with dose, while those at lower dose range were significantly higher than would be expected by a downward extraporation from the linear relation. Partial-hit or partial-target kinetics events appeared at very low dose exposure. (author)

  6. 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)

  7. Quantitative assessment of pulmonary function using low dose multi-slice spiral CT in smoker

    International Nuclear Information System (INIS)

    Chen Huai; Zeng Qingsi; Zheng Jinping; Guan Yubao; Zhang Chaoliang; Cen Renli

    2012-01-01

    Objective: To evaluate the clinical feasibility of low dose MSCT for quantitative assessment of pulmonary function in smokers. Methods: One hundred and forty-six patients with chronic objective pulmonary disease (COPD) including 109 smokers (74.6%) and 37 non-smokers (25.3%) underwent pulmonary function test and low-dose MSCT scan. All data were analyzed using computer-aided lung analysis software. Pulmonary function parameters from low-dose MSCT were compared between smokers and non-smokers and also compared with pulmonary function test in non-smokers (Pearson test). Results: In smokers, the average volume at full inspiratory phase (Vin) was (5125 ± 862 ) ml, mean lung attenuation was (-902 ± 26) HU, mean lung density was (0.0984 ± 0.0260 ) g/cm 3 , emphysema volume was (2890 ±1370) ml. The average volume at full expiratory phase (Vex) was (2756 ±1027) ml, mean lung attenuation was (-811 ±62) HU, mean lung density was (0.1878 ±0.0631) g/cm 3 , emphysema volume was (685 ±104) ml. In non-smokers, the average Vin was (3734 ± 759) ml, mean lung attenuation was (-876 ±40) HU,mean lung density was (0.1244 ±0.0401)g/cm 3 , emphysema volume was ( 1503 ± 1217) ml. The average Vex was (1770 ± 679) ml, mean lung attenuation was (-765 ± 56) HU, mean lung density was (0.2360 ± 0.0563) g/cm 3 , emphysema volume was (156 ± 45) ml. There were significant differences between smokers and non-smokers (P<0.01). The Vex/Vin was correlated with residual volume/total lung capacity (RV/TLC, r=0.60, P<0.01), and Vin was correlated with TLC (r=0.58, P<0.01), Vex with RV (r=0.59, P<0.01). Pixel index (PI) -950 in was correlated with FEV 1% pre and FEV1/FVC% (r=-0.53, -0.62, respective, P<0.01), Pl-950ex was correlated with FEV1 % pre and FEV1/FVC% (r=-0.71, -0.77, respective, P<0.01). Conclusion: Low-dose MSCT can be a potential imaging tool for quantitative pulmonary function assessment in smokes. (authors)

  8. Lifestyle, sun worshipping and sun tanning - what about UV-A sun beds?

    International Nuclear Information System (INIS)

    Thune, P.

    1991-01-01

    This article considers the effects of ultraviolet (UV) light from the sun and UV-A sun beds on the skin. Sun worshipping and sun therapy has been en vogue for centuries, but in another way than used today. A changing lifestyle has led to an increase of various skin diseases, including skin cancer. Short wave UV-light (UV-B) in particular has been blamed for inducing not only erythema and pigmentation but also more chronic skin lesions. Long wave UV-light (UV-A) has been shown to be the cause of similar changes to the skin but the pigmentation is of another quality and affords less protection against the harmful effects of UV-B. A concept of sun reactive skin typing has been created. This is based on self-reported responses to an initial exposure to sun as regards tanning ability and erythema reaction. These two factors have certain practical consequences, not only for UV-phototherapy but also for a person's risk of developing skin cancer. Recently, several research groups and dermatologists have discouraged extensive use of UV-A sun beds because of side effects of varying degrees of seriousness. The possible implications of these side effects for the organism are not fully elucidated and may be more profound than known today. The British Photodermatology Group has issued more stringent rules for persons who, despite advice to the contrary, still wish to use UV-A sun beds. 14 refs., 1 tab

  9. Pre-irradiation at a low dose-rate blunted p53 response

    International Nuclear Information System (INIS)

    Takahashi, Akihisa

    2002-01-01

    We investigated whether chronic irradiation at a low dose-rate interferes with the p53-centered signal transduction pathyway induced by radiation in human cultured cells and C57BL/6N mice. In in vitro experiments, we found that a challenge with X-ray irradiation immediately after chronic irradiation resulted in lower levels of p53 than those observed after the challenge alone in glioblastoma cells (A-172). In addition, the levels of p53-centered apoptosis and its related proteins after the challenge were strongly correlated with the above-mentioned phenomena in squamous cell carcinoma cells (SAS/neo). In in vivo experiments, the accumulation of p53 and Bax, and the induction of apoptosis were observed dose-dependently in mouse spleen at 12 h after a challenge with X-rays (3.0 Gy). However, we found significant suppression of p53 and Bax accumulation and the induction of apoptosis 12 h after challenge irradiation at 3.0 Gy with a high doses-rate following chronic pre-irradiation (1.5 Gy, 0.001 Gy/min). These findings suggest that chronic pre-irradiation suppressed the p53 function through radiation-induced signaling and/or p53 stability. (author)

  10. 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

  11. 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

  12. 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...

  13. 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...

  14. '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)

  15. 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)

  16. 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.

  17. 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

  18. 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

  19. 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.)

  20. 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

  1. 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

  2. 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.

  3. 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)

  4. 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

  5. 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

  6. 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

  7. Study of morbidity in persons subjected to combined effect of low dose irradiation and alcohol

    International Nuclear Information System (INIS)

    Mashneva, N.I.; Zakharov, A.A.

    1990-01-01

    Materials related to study of morbidity in persons from one of the controled areas subjected to combined effect of low dose ionizing radiation and alcohol are presented. The group under control included persons living in the same area but not misusing alcohol. The morbidity analysis for the period of two years before the accident showed that the number of morbidity cases and days characterized by incapacity for work among 100 working persons was 1.2 and 1.35 times higher as compared to persons not misusing alcohol. Two years after the accident these values constitute 1.6 and 1.75 correspondingly. It is established on the basis of the dispensary examnations, that taking into account other equal conditions the number of morbidity cases related to cardiovasular deseases among the persons misusing alcohol increased (11 % against 6.8 % bycontrol). The number of other chronic morbidity cases does not differ from control values. 7 refs.; 2 tabs

  8. Low dose irradiation and risk of leukaemia: A case-control study

    International Nuclear Information System (INIS)

    Chobanova, N.; Bayrakova, A.

    1997-01-01

    The effect of low dose irradiation (medical X-ray diagnostic) on the developing of leukaemias in adults is investigated. The influence of non-radiation agents (occupational exposure to chemical carcinogens, past viral infections, family aggregations) to leukaemias are considered also. During this retrospective study 228 patients have been examined with the following diagnosis: acute myeloid leukaemia, chronic myelogenous leukaemias, myelodisplastic syndrome and non-Hodgkin lymphoma (diagnosed between 1991-1993). Each case has been matched with two controls. Statistically significant increase has been found in the risk of developing leukaemias after X-ray diagnostic irradiation (OR = 1.98, 95% CI = 1.14 ./. 3.46). Exposure to chemical agents is also associated with significant increase in the risk (OR = 1.98, 95% CI = 1.25 ./. 2.86). (author)

  9. Low doses of dextromethorphan attenuate morphine-induced rewarding via the sigma-1 receptor at ventral tegmental area in rats.

    Science.gov (United States)

    Chen, Shiou-Lan; Hsu, Kuei-Ying; Huang, Eagle Yi-Kung; Lu, Ru-Band; Tao, Pao-Luh

    2011-09-01

    Chronic use of morphine causes rewarding and behavioral sensitization, which may lead to the development of psychological craving. In our previous study, we found that a widely used antitussive dextromethorphan (known as a low affinity NMDA receptor antagonist), at doses of 10-20 mg/kg (i.p.), effectively decreased morphine rewarding in rats. In this study, we further investigated the effects and mechanisms of low doses of DM (μg/kg range) on morphine rewarding and behavioral sensitization. A conditioned place preference test was used to determine the rewarding and a locomotor activity test was used to determine the behavioral sensitization induced by the drug(s) in rats. When a low dose of DM (3 or 10 μg/kg, i.p.) was co-administered with morphine (5 mg/kg, s.c.), the rewarding effect, but not behavioral sensitization, induced by morphine was inhibited. The inhibiting effect of DM could be blocked by systemically administering a sigma-1 receptor antagonist, BD1047 (3 mg/kg, i.p.). When BD1047 (5 nmole/site) was locally given at the VTA, it also blocked the effects of a low dose of DM in inhibiting morphine rewarding. Our findings suggest that the activation of the sigma-1 receptor at the VTA may be involved in the mechanism of low doses of DM in inhibiting the morphine rewarding effect and the possibility of using extremely low doses of DM in treatment of opioid addiction in clinics. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  10. Plants ecotoxicology. A case of low doses and multi pollutant exposure

    Energy Technology Data Exchange (ETDEWEB)

    Geras' Kin, S.; Kim, J.; Evseeva, T.; Oudalova, A.; Dikarev, V. [Russian Institute of Agricultural Radiology and Agroecology, Obninsk (Russian Federation)

    2004-07-01

    In this report, results of long-term laboratory, 'green-house' and field experiments carried out on different species of wild and agricultural plants (spring barley, Scots pine, spider wort, bulb onion and others) to study toxic and genotoxic effects of low doses and concentrations of such common pollutants as acute and chronic {gamma}-radiation, heavy natural radionuclides, compounds of heavy and alkaline earth metals, pesticides are presented for the first time. Special attention is paid to eco-toxic effects of chronic low dose exposures, the dose-rate effect, synergistic and antagonistic effects of different factors' combined exposures and biological effects of incorporated radionuclides. The results of long-term field experiments in the 30-km Chernobyl NPP zone, in the vicinity of the facility for the processing and storage of radioactive wastes (Leningrad region), in the vicinity of the radium production industry storage cell (Komi Republic), at the site of an underground nuclear explosion (Perm region) are discussed. These findings suggest that the further evolution of investigations in this field would issue in the development of a theoretical bases and practical procedures for environmental protection against radioactivity, taking into account the new experimentally confirmed facts about the presence of such essentially important singularities of the biological effect of low ionizing radiation doses as the nonlinearity of a dose-effect relationship, radiation-induced genomic instability, phenomenon of radio-adaptation, increased probability of synergetic and antagonistic effects of the combined action of different nature factors. A development of a new concept of radiation protection for a human and biota should be based on the clear understanding of these effects and their contribution to the response of biological objects. (author)

  11. Low dose of caffeine enhances the efficacy of antidepressants in major depressive disorder and the underlying neural substrates.

    Science.gov (United States)

    Liu, Qing-Shan; Deng, Ran; Fan, Yuyan; Li, Keqin; Meng, Fangang; Li, Xueli; Liu, Rui

    2017-08-01

    Caffeine is one of the most frequently used psychoactive substances ingested mainly via beverage or food products. Major depressive disorder is a serious and devastating psychiatric disorder. Emerging evidence indicates that caffeine enhances the antidepressant-like activity of common antidepressant drugs in rodents. However, whether joint administration of low dose of caffeine enhances the antidepressant actions in depressed patients remains unclear. A total of 95 male inpatients were assigned to three groups and were asked to take either caffeine (60, 120 mg) or placebo (soymilk powder) daily for 4 wk on the basis of their current antidepressant medications. Results showed that chronic supplementation with low dose of caffeine (60 mg) produced rapid antidepressant action by reduction of depressive scores. Furthermore, low dose of caffeine improved cognitive performance in depressed patients. However, caffeine did not affect sleep as measured by overnight polysomnography. Moreover, chronic caffeine consumption elicited inhibition of hypothalamic-pituitary-adrenal axis activation by normalization of salivary cortisol induced by Trier social stress test. These findings indicated the potential benefits of further implications of supplementary administration of caffeine to reverse the development of depression and enhance the outcome of antidepressants treatment in major depressive disorder. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. 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.)

  13. 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

  14. 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.

  15. 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

  16. 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

  17. 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)

  18. 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

  19. 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.

  20. 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.

  1. 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)

  2. 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)

  3. 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)

  4. 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.

  5. 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.

  6. 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)

  7. 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)

  8. 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.)

  9. 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.

  10. 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.

  11. 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.

  12. Mitochondrial-Derived Oxidants and Cellular Responses to Low Dose/Low LET Ionizing Radiation

    International Nuclear Information System (INIS)

    Spitz, Douglas R.

    2009-01-01

    Exposure to ionizing radiation results in the immediate formation of free radicals and other reactive oxygen species (ROS). It has been assumed that the subsequent injury processes leading to genomic instability and carcinogenesis following radiation, derive from the initial oxidative damage caused by these free radicals and ROS. It is now becoming increasingly obvious that metabolic oxidation/reduction (redox) reactions can be altered by irradiation leading to persistent increases in steady-state levels of intracellular free radicals and ROS that contribute to the long term biological effects of radiation exposure by causing chronic oxidative stress. The objective during the last period of support (DE-FG02-05ER64050; 5/15/05-12/31/09) was to determine the involvement of mitochondrial genetic defects in metabolic oxidative stress and the biological effects of low dose/low LET radiation. Aim 1 was to determine if cells with mutations in succinate dehydrogenase (SDH) subunits C and D (SDHC and SDHD in mitochondrial complex II) demonstrated increases in steady-state levels of reactive oxygen species (ROS; O 2 - and H 2 O 2 ) as well as demonstrating increased sensitivity to low dose/low LET radiation (10 cGy) in cultured mammalian cells. Aim No.2 was to determine if mitochondrially-derived ROS contributed to increased sensitivity to low dose/low LET radiation in mammalian cells containing mutations in SDH subunits. Aim No.3 was to determine if a causal relationship existed between increases in mitochondrial ROS production, alterations in electron transport chain proteins, and genomic instability in the progeny of irradiated cells. Evidence gathered in the 2005-2009 period of support demonstrated that mutations in genes coding for mitochondrial electron transport chain proteins (ETC); either Succinate Dehydrogenase (SDH) subunit C (SDHC) or subunit D (SDHD); caused increased ROS production, increased genomic instability, and increased sensitivity to low dose/low LET

  13. Low-dose narrow-band UVB phototherapy combined with topical therapy is effective in psoriasis and does not inhibit systemic T-cell activation

    NARCIS (Netherlands)

    de Rie, M. A.; Out, T. A.; Bos, J. D.

    1998-01-01

    Psoriasis is a chronic T-cell-mediated inflammatory skin disease which can be treated with topical medication, phototherapy or systemic medication. A subgroup of psoriatic patients does not respond to monotherapy and needs combination therapy. We used low-dose narrow-band UVB phototherapy, combined

  14. Radiation sources providing increased UVA/UVB ratios induce photoprotection dependent on the UVA dose in hairless mice.

    Science.gov (United States)

    Reeve, Vivienne E; Domanski, Diane; Slater, Michael

    2006-01-01

    In studies involving mice in which doses of UVA (320-400 nm) and UVB (290-320 nm) radiation were administered alone or combined sequentially, we observed a protective effect of UVA against UVB-induced erythema/edema and systemic suppression of contact hypersensitivity. The UVA immunoprotection was mediated by the induction of the stress enzyme heme oxygenase-1 (HO-1) in the skin, protection of the cutaneous Th1 cytokines interferon-gamma (IFN-gamma) and IL-12 and inhibition of the UVB-induced expression of the Th2 cytokine IL-10. In this study, we seek evidence for an immunological waveband interaction when UVA and UVB are administered concurrently to hairless mice as occurs during sunlight exposure in humans. A series of spectra providing varying ratios of UVA/UVB were developed, with the UVA ratio increased to approximately 3.5 times the UVA component in solar simulated UV (SSUV). We report that progressively increasing the UVA component of the radiation while maintaining a constant UVB dose resulted in a reduction of both the erythema/edema reaction and the degree of systemic immunosuppression, as measured as contact hypersensitivity. The UVA-enhanced immunoprotection was abrogated in mice treated with a specific HO enzyme inhibitor. UVA-enhanced radiation also upregulated the expression of cutaneous IFN-gamma and IL-12 and inhibited expression of both IL-6 and IL-10, compared with the activity of SSUV. The results were consistent with the previously characterized mechanisms of photoprotection by the UVA waveband alone and suggest that the UVA component of solar UV may have beneficial properties for humans.

  15. 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)

  16. 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.

  17. 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.

  18. 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)

  19. 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.

  20. 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

  1. 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

  2. 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

  3. 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.)

  4. Impacts of low dose rate irradiation on the fertility, fecundity and hatchling survival of Japanese rice fish (medaka, Oryzias latipes)

    International Nuclear Information System (INIS)

    Hinton, T.G.; Coughlin, D.P.; Marsh, L.C.; Yi, Yi; Winn, R.

    2004-01-01

    A renewed international interest in the effects on biota from low dose rate irradiation has recently occurred. Much of that interest is centered on the relevance of previously accepted dose rate guidelines (e.g. 10 mGy d -1 for aquatic biota) suggested by the ICRP and IAEA. All parties concerned seem to agree that additional data are needed on population level impacts from chronic low-level exposures to radionuclides. Using a Low Dose Rate Irradiation Facility (LoDIF), we conducted an experiment on the fecundity, fertility and hatchling survival of Japanese Rice Fish (medaka, Oryzias latipes). Fish were exposed externally to 137 Cs from juvenile through adulthood at mean dose rates of 3.5, 35 and 350 mGy d -1 . Fish were bred at maturity and the following endpoints were examined: 1) the number of eggs produced; 2) the percent of eggs that hatched; and 3) the survival of hatchlings 20-days post hatch. The influence of gender was examined by breeding irradiated males with control females; control males with irradiated females; irradiated males with irradiated females; and control males with control females. The data contribute to our understanding the impacts of low dose rate irradiation. (author)

  5. Effective Treatment of Intestinal Behçet's Disease with Long-Term, Low-Dose Clarithromycin

    Directory of Open Access Journals (Sweden)

    Yukiya Hakozaki

    2013-03-01

    Full Text Available A 51-year-old man was referred for body weight loss and lower right abdominal pain. Total colonoscopy revealed discrete and round ulceration at the ileocecal valve, and he was diagnosed with intestinal Behçet's disease (BD. By treatment with glucocorticoid, colchicine and salazosulfapyridine, the symptoms and ulceration were improved, but cessation of glucocorticoid resulted in relapse of ulceration at the terminal ileum. Long-term, low-dose treatment with clarithromycin (CAM was implemented for chronic respiratory infections. Furthermore, we expected that this CAM treatment would also be effective in BD. During this long-term, low-dose treatment with CAM, discrete ulceration at the terminal ileum was never revealed by follow-up total colonoscopy once or twice per year for 7 years. No reports have described the effectiveness of this treatment in patients with intestinal BD; however, we confirm that long-term treatment with low-dose CAM might have clinical benefits for patients with intestinal BD.

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. Effect of continuous exposure to very low dose rates of gamma rays on life span and neoplasia in mice

    International Nuclear Information System (INIS)

    Tanaka, I.B. III; Tanaka, Satoshi; Ichinohe, Kazuaki; Matsumoto, Tsuneya; Otsu, Hiroshi; Oghiso, Yoichi; Sato, Fumiaki; Matsushita, Satoru

    2008-01-01

    Late effects of continuous exposure to ionizing radiation are potential hazards to workers in radiation facilities as well as to the general public. In the recent years, low-dose-rate and low-dose effects have become a serious concern. Using a total of 4,000 mice, we studied the late biological effects of chronic exposure to low-dose-rate radiation on life span and neoplasia. Two thousand male and 2000 female 8-week-old specific pathogen free (SPF) B6C3F1 mice were randomly divided into 4 groups, one non-irradiated (control) and three irradiated. The irradiated groups were exposed to 137 Cs gamma rays at dose-rates of 21, 1.1 and 0.05 mGy day -1 for approximately 400 days with total doses equivalent to 8000, 400 and 20 mGy, respectively. All mice were kept under SPF conditions until natural death and pathological examination was performed to determine the cause of death. Statistical analyses showed that the life spans of mice of both sexes irradiated with 21 mGy day -1 (P -1 (P 86.7% of all deaths. Compared to the non-irradiated controls, incidences of lethal neoplasms were significantly increased for myeloid leukaemia and hemangiosarcoma in males, soft tissue neoplasms and malignant granulosa cell tumors in females exposed to 21 mGy day -1 . The number of multiple primary neoplasms per mouse was significantly increased in mice irradiated at 21 mGy day -1 . Our results suggest that life shortening in mice continuously exposed to low dose-rate gamma rays is due to early death from a variety of neoplasms and not from increased incidence of specific lethal neoplasms. (author)

  12. 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

  13. 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

  14. 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.

  15. Characterisation of optical filters for broadband UVA radiometer

    Science.gov (United States)

    Alves, Luciana C.; Coelho, Carla T.; Corrêa, Jaqueline S. P. M.; Menegotto, Thiago; Ferreira da Silva, Thiago; Aparecida de Souza, Muriel; Melo da Silva, Elisama; Simões de Lima, Maurício; Dornelles de Alvarenga, Ana Paula

    2016-07-01

    Optical filters were characterized in order to know its suitability for use in broadband UVA radiometer head for spectral irradiance measurements. The spectral transmittance, the angular dependence and the spatial uniformity of the spectral transmittance of the UVA optical filters were investigated. The temperature dependence of the transmittance was also studied.

  16. Sperm parameters in rats after low-dose irradiation of sex cells in male parents during two cycles of gametogenesis

    International Nuclear Information System (INIS)

    Karpenko, N.O.; Chub, N.N.; Brizgalova, G.A.

    2001-01-01

    Chronic combined (internal and external) irradiation in low doses (absorbed doses 0.4 - 3.6 cGy) during two cycles of gametogenesis results in defective stimulation of spermatogenesis in male rats and provokes genotoxic action. The offspring from fathers with 0.7 and 3.6 cGy irradiation have decreased viability and oligozoospermia in mature age. The offsprings from the father with 3.6 cGy have increased sensitivity to weak irradiation and react by increases oligozoospermia. The data are accord with the idea about more pronounced genetic radioresistance of premeiosis cells during gametogenesis

  17. 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

  18. 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

  19. Controlling powdery mildew (Sphaerotheca mors-uvae) of gooseberry (Ribes uva-crispa) with potassium bicarbonate and risk of phytotoxicity

    NARCIS (Netherlands)

    Wenneker, M.

    2016-01-01

    Powdery mildew (Sphaerotheca mors-uvae) severely infects young shoots, stems and fruits of gooseberry (Ribes uva-crispa). Environmental friendly and biological control measures are being sought throughout the world. Especially in organic currant growing effective control measures are needed,

  20. Stair walking is more energizing than low dose caffeine in sleep deprived young women.

    Science.gov (United States)

    Randolph, Derek D; O'Connor, Patrick J

    2017-05-15

    The acute energizing effect of exercise and caffeine has never been examined in a single study of adults with chronic sleep deprivation but evidence from a study of this type could help individuals choose between these two common alertness-enhancing options. The apriori primary aim of this experiment was to compare the influence of 10-min of low-to-moderate intensity stair walking to the consumption of capsules containing 50mg caffeine or flour (placebo) on feelings of energy in physically active, college female caffeine users with chronic insufficient sleep. Effects on secondary outcomes related to feelings of energy also were assessed. A repeated measures crossover experiment was conducted with 18 college women (18-23years) who reported (i) daily caffeine consumption that was not extreme (40-400mg), (ii) typical leisure time physical activity that was not extreme (at least 2 weekly mild 15-min or longer bouts and no >5 strenuous 15-min or longer bouts), and (iii) sleeping memory (N-back), sustained attention (CPT), simple reaction time (SRT), and motivation to complete the cognitive tasks were measured before and after a 10-min exercise condition (20min seated rest followed by 10min of low-to-moderate intensity stair walking) and compared to both a caffeine condition (50mg caffeine capsule followed by 30min of seated rest) and a similar flour (placebo) capsule condition. Condition (exercise, caffeine, placebo)×Time (Baseline, Post-1, Post-2, and for mood Post-3) ANCOVAs (controlling for Condition order) tested the hypothesized effects. Condition×Time interactions showed that stair walking increased POMS-BF vigor at Post-1 compared to both placebo and caffeine. Other interactions were not significant. A brief bout of low-to-moderate intensity stair walking has transient energizing effects that exceed a low dose of caffeine for active young women with chronic insufficient sleep. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. 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)

  2. 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

  3. 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.

  4. 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.

  5. 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)

  6. 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

  7. 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)

  8. Reduction in life span on normal human fibroblasts exposed to low-dose radiation in heavy-ion radiation field

    International Nuclear Information System (INIS)

    Suzuki, Masao; Yamaguchi, Chizuru; Yasuda, Hiroshi; Uchihori, Yukio; Fujitaka, Kazunobu

    2003-01-01

    We studied the effect of in vitro life span in normal human fibroblasts exposed to chronically low-dose radiation in heavy-ion radiation field. Cells were cultured in a CO 2 incubator, which was set in the irradiation room for biological study of heavy ions in the Heavy Ion Medical Accelerator in Chiba (HIMAC) at National Institute of Radiological Sciences (NIRS), and exposed to scattered radiations produced with heavy-ion beams throughout the life span of the cell population. Absorbed dose, which was measured using a thermoluminescence dosimeter(TLD) and a Si-semiconductor detector, was to be 1.4 mGy per day when operating the HIMAC machine for biological experiments. The total population doubling number of the exposed cells reduced to 79-93% of non-exposed control cells in the three independent experiments. There is evidence that the exposure of chronically low-dose radiation in heavy-ion radiation field promotes the life-span reduction in cellular level. (author)

  9. Low dose prenatal alcohol exposure does not impair spatial learning and memory in two tests in adult and aged rats.

    Directory of Open Access Journals (Sweden)

    Carlie L Cullen

    Full Text Available Consumption of alcohol during pregnancy can have detrimental impacts on the developing hippocampus, which can lead to deficits in learning and memory function. Although high levels of alcohol exposure can lead to severe deficits, there is a lack of research examining the effects of low levels of exposure. This study used a rat model to determine if prenatal exposure to chronic low dose ethanol would result in deficits in learning and memory performance and if this was associated with morphological changes within the hippocampus. Sprague Dawley rats were fed a liquid diet containing 6% (vol/vol ethanol (EtOH or an isocaloric control diet throughout gestation. Male and Female offspring underwent behavioural testing at 8 (Adult or 15 months (Aged of age. Brains from these animals were collected for stereological analysis of pyramidal neuron number and dendritic morphology within the CA1 and CA3 regions of the dorsal hippocampus. Prenatal ethanol exposed animals did not differ in spatial learning or memory performance in the Morris water maze or Y maze tasks compared to Control offspring. There was no effect of prenatal ethanol exposure on pyramidal cell number or density within the dorsal hippocampus. Overall, this study indicates that chronic low dose prenatal ethanol exposure in this model does not have long term detrimental effects on pyramidal cells within the dorsal hippocampus or impair spatial learning and memory performance.

  10. Low dose ketamine use in the emergency department, a new direction in pain management.

    Science.gov (United States)

    Pourmand, A; Mazer-Amirshahi, M; Royall, C; Alhawas, R; Shesser, R

    2017-06-01

    There is a need for alternative non-opioid analgesics for the treatment of acute, chronic, and refractory pain in the emergency department (ED). Ketamine is a fast acting N-methyl-d-aspartate (NMDA) receptor antagonist that provides safe and effective analgesia. The use of low dose ketamine (LDK) (Ketamine was shown to be efficacious at treating a variety of painful conditions. It has a favorable adverse effect profile when given at sub-dissociative doses. Studies have also compared LDK to opioids in the ED. Although ketamine's analgesic effects were not shown to be superior, they were comparable to opioids. LDK has the benefit of causing less respiratory depression. It likely has less wide spread potential for abuse. Nursing protocols for the administration of LDK have been studied. We believe that LDK has the potential to be a safe and effective alternative and/or adjunct to opioid analgesics in the ED. Additional studies are needed to expand upon and determine the optimal use of LDK in the ED. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Methadone ameliorates multiple-low-dose streptozotocin-induced type 1 diabetes in mice

    International Nuclear Information System (INIS)

    Amirshahrokhi, K.; Dehpour, A.R.; Hadjati, J.; Sotoudeh, M.; Ghazi-Khansari, M.

    2008-01-01

    Type 1 diabetes is an autoimmune disease characterized by inflammation of pancreatic islets and destruction of β cells by the immune system. Opioids have been shown to modulate a number of immune functions, including T helper 1 (Th1) and T helper 2 (Th2) cytokines. The immunosuppressive effect of long-term administration of opioids has been demonstrated both in animal models and humans. The aim of this study was to determine the effect of methadone, a μ-opioid receptor agonist, on type 1 diabetes. Administration of multiple low doses of streptozotocin (STZ) (MLDS) (40mg/kg intraperitoneally for 5 consecutive days) to mice resulted in autoimmune diabetes. Mice were treated with methadone (10mg/kg/day subcutaneously) for 24days. Blood glucose, insulin and pancreatic cytokine levels were measured. Chronic methadone treatment significantly reduced hyperglycemia and incidence of diabetes, and restored pancreatic insulin secretion in the MLDS model. The protective effect of methadone can be overcome by pretreatment with naltrexone, an opioid receptor antagonist. Also, methadone treatment decreased the proinflammatory Th1 cytokines [interleukin (IL)-1β, tumor necrosis factor-α and interferon-γ] and increased anti-inflammatory Th2 cytokines (IL-4 and IL-10). Histopathological observations indicated that STZ-mediated destruction of β cells was attenuated by methadone treatment. It seems that methadone as an opioid agonist may have a protective effect against destruction of β cells and insulitis in the MLDS model of type 1 diabetes

  12. The Protective Effects of Oral Low-dose Quercetin on Diabetic Nephropathy in Hypercholesterolemic Mice

    Directory of Open Access Journals (Sweden)

    Isabele Beserra Santos Gomes

    2015-09-01

    Full Text Available Aims: Diabetic nephropathy (DN is one of the major causes of end-stage renal disease, and the incidence of DN is increasing worldwide. Considering our previous report indicating that chronic treatment with oral low-dose quercetin (10 mg/Kg demonstrated renoprotective, anti-oxidative and anti-apoptotic effects in the C57BL/6J model of diabetic nephropathy, we investigated whether this flavonoid could also have beneficial effects in concurrent DN and spontaneous atherosclerosis using the apolipoprotein E-deficient mouse (apoE-/-. Methods: DN was induced by streptozotocin (100 mg/kg/day, for 3 days in adult apoE-/-mice. Six weeks later, the mice were divided into the following groups: diabetic apoE-/- mice treated with quercetin (DQ, 10 mg/kg/day, 4 weeks, diabetic ApoE-/- mice treated with vehicle (DV and non-treated non-diabetic (ND mice.Results: Quercetin treatment caused a reduction in polyuria (~30%, glycemia (~25%, abolished the hypertriglyceridemia and had significant effects on renal function, including decreased proteinuria (~15% and creatininemia (~30%, which were accompanied by beneficial effects on the renal structural changes, including normalization of the index of glomerulosclerosis and kidney weight.Conclusions: Our data revealed that quercetin treatment significantly reduced DN in hypercholesterolemic mice by inducing biochemical and morphological modifications. Thus, this translational study highlights the importance of quercetin as a potential nutraceutical for the management of DN, including in diabetes associated with dyslipidemia.

  13. Lifetime radiation risks from low-dose rate radionuclides in beagles

    International Nuclear Information System (INIS)

    Goldman, M.; Rosenblatt, L.S.

    1985-01-01

    One of the largest, long-term (25-yr) animal studies on the effects of low-dose internal irradiation is almost completed. Some 335 beagles were given continuous exposure to graded 90 Sr [low linear energy transfer (LET)] in their diets (D-dogs) through adulthood. A second group (R-dogs) was given fractionated doses of 225 Ra (high LET) as young adults. A third group of 44 was given a single injection of 90 Sr as adults (S-dogs) to compare single to continuous dosages. All dogs were followed through their lifetimes. Only one of the 848 dogs is still alive. The animals were whole-body counted over their entire life span and were examined frequently for assessment of medical status. There were no acute radiation lethalities. Analyses of the large data base from these dogs have begun and preliminary indications are that 90 Sr, which was tested over a 1500-fold skeletal dose rate range, does not cause significant life shortening at average accumulation skeletal doses of ∼2500 rads (25 Gy) and that a curvilinear dose response curve for life shortening was seen at higher accumulation doses. The data will be discussed in terms of modern epidemiological concepts and quantifications will be related to certain parameters of human risk from acute or chronic radiation exposures

  14. Taenia crassiceps Infection Attenuates Multiple Low-Dose Streptozotocin-Induced Diabetes

    Directory of Open Access Journals (Sweden)

    Arlett Espinoza-Jiménez

    2010-01-01

    Full Text Available Taenia crassiceps, like other helminths, can exert regulatory effects on the immune system of its host. This study investigates the effect of chronic T. crassiceps infection on the outcome of Multiple Low Dose Streptozotocin-Induced Diabetes (MLDS. Healthy or previously T. crassiceps-infected mice received MLDS and type 1 diabetes (T1D symptoms were evaluated for 6 weeks following the induction of MLDS. T. crassiceps-infected mice displayed lower blood glucose levels throughout the study. A significantly lower percentage of T. crassiceps-infected mice (40% developed T1D compared to the uninfected group (100%. Insulitis was remarkably absent in T. crassiceps-infected mice, which had normal pancreatic insulin content, whereas uninfected mice showed a dramatic reduction in pancreatic insulin. Infected mice that received MLDS did not show an increase in their regulatory T cell population, however, they had a greater number of alternatively activated macrophages, higher levels of the cytokine IL-4, and lower levels of TNF-α. Therefore, infection with T. crassiceps causes an immunomodulation that modifies the incidence and development of MLDS-induced autoimmune diabetes.

  15. Osteomalacia and Fanconi's syndrome caused by long-term low-dose adefovir dipivoxil.

    Science.gov (United States)

    Wang, B-F; Wang, Y; Wang, B-Y; Sun, F-R; Zhang, D; Chen, Y-S

    2015-06-01

    Adefovir dipivoxil (ADV) is recommended for patients infected with lamivudine-refractory hepatitis B virus (HBV). We report a case of low-dose ADV-induced hypophosphatemic osteomalacia that initially presented as diffuse musculoskeletal pain. A 59-year-old Chinese man reported an 18-month history of severe chest wall pain and multiple bone pain during the previous 4 months with no antecedent trauma. There was no clinical evidence of an infectious, inflammatory or malignant process. Medical history showed that the patient had a history of chronic hepatitis B infection, and receiving lamivudine at a daily dose of 100 mg for 70 months. Lamivudine was changed to adefovir (10 mg/day) for the past 42 months. His serum inorganic phosphorus concentration was significantly low (0·4 mmol/l; 0·81-1·5 mmol/L), and the result of a urine routine test was abnormal. Combined with unbearable bone pain, spontaneous fractures, changes in laboratory markers and the result of ECT and other radiographic findings, the diagnosis of Fanconi's syndrome with osteomalacia was established. Dramatic clinical, laboratory and imaging improvement was observed after ADV discontinuation. This case indicates that Fanconi's syndrome with osteomalacia can be acquired by a chronic hepatitis B patient taking ADV at a conventional dosage of 10 mg/day. Therefore, patients with HBV treated with long-term ADV should be regularly monitored for renal function, serum calcium and serum phosphate. Urine testing for ion concentration should also be undertaken. © 2015 John Wiley & Sons Ltd.

  16. Non-linear dose-response of aluminium hydroxide adjuvant particles: Selective low dose neurotoxicity

    International Nuclear Information System (INIS)

    Crépeaux, Guillemette; Eidi, Housam; David, Marie-Odile; Baba-Amer, Yasmine; Tzavara, Eleni; Giros, Bruno; Authier, François-Jérôme; Exley, Christopher; Shaw, Christopher A.; Cadusseau, Josette

    2017-01-01

    Aluminium (Al) oxyhydroxide (Alhydrogel ® ), the main adjuvant licensed for human and animal vaccines, consists of primary nanoparticles that spontaneously agglomerate. Concerns about its safety emerged following recognition of its unexpectedly long-lasting biopersistence within immune cells in some individuals, and reports of chronic fatigue syndrome, cognitive dysfunction, myalgia, dysautonomia and autoimmune/inflammatory features temporally linked to multiple Al-containing vaccine administrations. Mouse experiments have documented its capture and slow transportation by monocyte-lineage cells from the injected muscle to lymphoid organs and eventually the brain. The present study aimed at evaluating mouse brain function and Al concentration 180 days after injection of various doses of Alhydrogel ® (200, 400 and 800 μg Al/kg of body weight) in the tibialis anterior muscle in adult female CD1 mice. Cognitive and motor performances were assessed by 8 validated tests, microglial activation by Iba-1 immunohistochemistry, and Al level by graphite furnace atomic absorption spectroscopy. An unusual neuro-toxicological pattern limited to a low dose of Alhydrogel ® was observed. Neurobehavioural changes, including decreased activity levels and altered anxiety-like behaviour, were observed compared to controls in animals exposed to 200 μg Al/kg but not at 400 and 800 μg Al/kg. Consistently, microglial number appeared increased in the ventral forebrain of the 200 μg Al/kg group. Cerebral Al levels were selectively increased in animals exposed to the lowest dose, while muscle granulomas had almost Completely disappeared at 6 months in these animals. We conclude that Alhydrogel ® injected at low dose in mouse muscle may selectively induce long-term Al cerebral accumulation and neurotoxic effects. To explain this unexpected result, an avenue that could be explored in the future relates to the adjuvant size since the injected suspensions corresponding to the lowest dose

  17. Palliation by Low-Dose Local Radiation Therapy for Indolent Non-Hodgkin Lymphoma

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Elisa K. [Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario (Canada); Fung, Sharon [Department of Clinical Study Coordination and Biostatistics, Princess Margaret Hospital, University of Toronto, Toronto, Ontario (Canada); Gospodarowicz, Mary; Hodgson, David; Wells, Woodrow; Sun, Alexander [Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario (Canada); Pintile, Melania [Department of Clinical Study Coordination and Biostatistics, Princess Margaret Hospital, University of Toronto, Toronto, Ontario (Canada); Department of Radiation Oncology, Southlake Regional Health Centre, Newmarket, Ontario (Canada); Tsang, Richard W., E-mail: richard.tsang@rmp.uhn.on.ca [Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario (Canada)

    2011-12-01

    Purpose: The purpose of this study was to assess the efficacy of a 2 Multiplication-Sign 2 Gy (total dose, 4 Gy) palliative radiation therapy (RT) regimen for treating patients with indolent non-Hodgkin lymphoma (NHL) in terms of response rate, response duration, and symptom relief. Methods and Materials: A retrospective chart review was conducted. Between 2003 and 2007, 54 patients with NHL were treated to 85 anatomical sites with a 2 Multiplication-Sign 2 Gy palliative regimen. Local response was assessed by clinical and/or radiographic data. Symptoms before and after treatment for each site treated were obtained from clinical notes in patient medical records. Median follow-up time was 1.3 years. Results: For the 54 patients, the median age at time of treatment was 71.1 years old, and 57% of them were male. Of the 85 disease sites treated, 56% of sites had indolent histology, 28% of sites were diagnosed with chronic lymphocytic leukemia (CLL), 13% of sites had aggressive histology, and 2% of sites were shown to have other histology. Overall response rate (ORR) was 81% (49% complete response [CR], 32% partial response [PR]). The 2-year rate for freedom from local progression was 50% (95% CI, 37%-61%). The ORR for follicular lymphoma, Mucosa associated lymphoid tissue (MALT), and marginal zone lymphoma (MZL) histology was 88%, compared with a 59% rate for CLL histology (p = 0.005). While the ORR was similar for tumors of different sizes, the CR rate for patients with tumors <5 cm tended to be higher than those with tumors >10 cm (CR rate of 57% vs. 27%, respectively; p = 0.06). For the 48 sites with clearly documented symptoms at pretreatment, 92% of sites improved after low-dose RT. Conclusions: Short-course low-dose palliative radiotherapy (2 Multiplication-Sign 2 Gy) is an effective treatment that results in high response rates for indolent non-Hodgkin lymphoma. This treatment regimen provides effective symptomatic relief for tumor bulk of all sizes.

  18. Primary study of quantitative measurement in different grades of COPD using low-dose multislice CT

    International Nuclear Information System (INIS)

    Li Yiming; Yin Jianzhong; Yang Wenjie; Tan Zhengshuai

    2012-01-01

    Objective: To study the feasibility of airway measurement at the trunk of apical bronchus of right upper lobe in chronic obstructive pulmonary disease (COPD), and airway dimensions and lung density changes in different COPD stages. Methods: 1) Fifteen randomly selected COPD patients underwent low -dose chest multi -slice CT scan. The wall thickness-to-diameter ratio (TDR) and percentage wall area (WA%) at apical bronchus of right upper lobe section and mean TDR and WA% of small airway (<2 mm) were calculated. 2) Another fifty-five randomly selected COPD patients were divided into 4 groups on the basis of pulmonary function tests. There were sixteen patients with grade 1, sixteen patients with grade 2, fourteen patients with grade 3. and nine patients with grade 4. Fifteen non-COPD patients were selected as controls. The total lung was scanned with low-dose multi-slice CT during inspiration. The mean lung attenuation (MLA) and voxel index (VI) were measured. Inner area of bronchus (A i ), TDR and WA% of the apical bronchus of right upper lobe were measured. Results: 1) The TDR of the apical bronchus of right were smaller than the mean TDR of the small airways; The WA% of the apical bronchus of right were larger than the mean WA% of the small airways; but there were good correlation (r=0.793 and 0.784, respectively). 2) The MLA values were decreased with increase of COPD stage. The VI values were increased with increase of COPD stage. However, the values did not differ between adjacent stages. The luminal areas of stage 3-4 patients were smaller than that of other stages. There was no statistics difference in TDR between adjacent groups, except between stages 3 and 4. For WA%, the higher stage group had higher WA%. Conclusion: There were good correlations for TDR and WA% between the apical bronchus of right upper lobe and small airway. WA% is the most sensitive index for detecting thickened airway. (authors)

  19. What happens at very low levels of radiation exposure ? Are the low dose exposures beneficial ?

    International Nuclear Information System (INIS)

    Deniz, Dalji

    2006-01-01

    . This adaptive response seems to be the manifestation of a protective effect that may reduce risk at very low doses. Current knowledge in molecular biology shows no evidence of a threshold effect for Stochastic Effects. Therefore, any level of radiation may be considered to cause them. Conversely, some studies show that low levels of irradiation are in fact beneficial to the health (Radiation Hormesis). However, in the absence of clear scientific evidence, the regulators adopted a conservative approach and consider all levels of radiation as being potentially damaging to the human body (LNT theory). According to LNT theory; the effects of low doses of ionizing radiation can be estimated by linear extrapolation from effects observed by linear extrapolation from effects observed by high doses. There is not any safe dose because even very low doses of ionizing radiation produce some biological effect. The results of many investigations do not support the LNT theory. Furthermore relationship between environmental radon concentrations and lung cancer even contradict this theory and clearly suggest a hermetic effect -radiation hormesis-. Although data are still incomplete, extensive epidemiological studies have indicated that radiation hormesis is really exist. In this review, contradictory evidence Linear No-Threshold Theory and Radiation Hormesis Effect is discussed

  20. On possible risks of low-dose irradiation

    International Nuclear Information System (INIS)

    Hug, O.; Gesellschaft fuer Strahlen- und Umweltforschung m.b.H., Neuherberg/Muenchen

    1974-01-01

    The survey on more recent experimental and epidemiological data and newer concepts for a realistic estimation of the radiation risk leads to the conclusion that for radiation late damages and possibly also for genetic damages with a chronical radiation exposure in the order of magnitude of the natural radiation exposure and probably also in the order of magnitude of the maximum permissible radiation dose, the risk is very probably lower than is to be expected based on the findings after relatively high doses and dose rates. A few less direct comparative studies have detected a time factor of 3 to 5. Considering the analysis of the RBW demely ionizing radiation which at high doses is not greater than 3, increases with decreasing dose and according to biophysical considerations, can possibly reach a value of 30, an effectiveness reduced by a factor of 10 of small doses and dose rates of loosely ionizing radiation would be even to be expected. All radiobiological knowledge on the effect of ionizing radiation allows one to expect that even smallest radiation doses can cause cellular damages due to the linear irreversable components of the radiation effect and probably that these damages can even be the starting point of a malignant tumour. Regarding this cancer-initiating effect however, the effectiveness of loosely ionizing radiation per rad in the region of natural radiation exposure lie considerably below that existing at high doses and dose rates. Whether however this initial carcinogenic effect of very small doses is at all noticeable during the average life duration in an increase of the spontaneous age-specific tumour rate is questionable if the assumption is confirmed that with decreasing dose, the time manifestation of the radiation induced tumours is delayed. (orig./LH) [de

  1. 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.

  2. Examination of solar simulators used for the determination of sunscreen UVA efficacy.

    Science.gov (United States)

    Sayre, Robert M; Dowdy, John C

    2010-01-01

    The U.S. FDA recently proposed both in vivo and in vitro UVA efficacy tests for sunscreen products with the lower result used to establish the sunscreen's labeled UVA protection claim. The FDA stated their rationale for dual tests was concern that the in vivo test method overemphasizes UVA-2 (320-340 nm) photoprotection. We attribute FDA's observation to the relative lack, compared to sunlight, of UVA-1 (340-400 nm) radiation in the current JCIA UVA solar simulator specification, allowing the method to generate higher UVA protection factors than sunscreens will provide in sunlight. Our work is based upon comparisons of Air Mass 1.0 sunlight to variously filtered UVA solar simulators. Sources near the JCIA UVA-2/UVA limits (8-20%) had a goodness of fit to solar UVA of only 67-79%. We propose that instead of using ratios of UVA-2 to UVA the standard should be a goodness of fit to the UVA region of an Air Mass 1 solar reference spectrum. As the spectral distribution of solar UVA varies much less than UVB, sunlight of reasonable zenith angles of < or = 60 degrees will have similar spectral shapes and approximate risk spectrum. Goodness of fit to this spectrum will produce UVA protection values predictive to those actually achieved in sunlight of different zenith angles.

  3. Animal and human responses to UVA and UVB

    International Nuclear Information System (INIS)

    Saunders, R.; Cridland, N.; Kowalczuk, C.

    1997-12-01

    Ultraviolet radiation (UVR) comprises the most energetic region of the optical radiation spectrum and is able to induce photochemical changes in the superficial tissues of animals and people which can lead to various acute or chronic adverse health effects. The evidence concerning experimental studies of animals and, where available, volunteers of the effects of occupationally relevant wavelengths (principally UVB, 280-315 rim, and UVA, 315-400 nm) has been reviewed. Experimental studies on animals indicate that exposure to UVR elicits transient (acute) and long-lasting (chronic) effects in the skin and the eye, the severity of which increases in proportion to the exposure. Transient responses have also been investigated in human volunteers and these include adaptive changes such as immediate pigment darkening, melanogenesis and epidermal hyperplasia, and inflammatory responses such as erythema in the skin and keratitis and conjunctivitis in the eye. Irreversible, long-lasting changes also occur following exposure; these include photoageing of the skin, and the development of cataracts in the lens of the eye. Animal studies show that UVR can act either as a complete carcinogen, capable of inducing tumours when applied by itself, or as a co-carcinogen acting in combination with tumour initiators and promoters. The interaction of UVR with the immune system is complex. Exposure to UVR affects the immune system, depressing certain types of cell-mediated antigen-specific responses. Variable immunosuppressive effects have also been reported in humans. In addition, exogenous chemical sensitisers can initiate phototoxic or photoallergic responses in humans and animals; these can precede the development of more persistent idiopathic photodermatoses in which the sensitiser may be an endogenous chemical or antigen. Recommendations for further research are made. (author)

  4. 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)

  5. 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)

  6. 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.

  7. 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.

  8. Diagnostic accuracy of low-dose versus ultra-low-dose CT for lumbar disc disease and facet joint osteoarthritis in patients with low back pain with MRI correlation

    International Nuclear Information System (INIS)

    Lee, Sun Hwa; Yun, Seong Jong; Jo, Hyeon Hwan; Kim, Dong Hyeon; Song, Jae Gwang; Park, Yong Sung

    2018-01-01

    To compare the image quality, radiation dose, and diagnostic performance between low-dose (LD) and ultra-low-dose (ULD) lumbar-spine (L-spine) CT with iterative reconstruction (IR) for patients with chronic low back pain (LBP). In total, 260 patients with chronic LBP who underwent L-spine CT between November 2015 and September 2016 were prospectively enrolled. Of these, 143 underwent LD-CT with IR and 117 underwent ULD-CT with IR. The patients were divided according to their body mass index (BMI) into BMI1 (<22.9 kg/m 2 ), BMI2 (23.0-24.9 kg/m 2 ), and BMI3 (≥25 kg/m 2 ) groups. Two blinded radiologists independently evaluated the signal-to-noise ratio (SNR), qualitative image quality, and final diagnoses (lumbar disc disease and facet joint osteoarthritis). L-spine MRIs interpreted by consensus were used as the reference standard. All data were statistically analyzed. ULD protocol showed significantly lower SNR for all patients (p < 0.001) except the vertebral bodies and lower qualitative image quality for BMI3 patients (p ≤ 0.033). There was no statistically significant difference between ULD (sensitivity, 95.1-98.1%; specificity, 92.5-98.7%; accuracy, 94.6-98.0%) and LD protocols (sensitivity, 95.6-100%; specificity, 95.5-98.9%; accuracy, 97.4-98.1%), (all p≥0.1) in the BMI1 and BMI2; while dose was 60-68% lower with the ULD protocol. Interobserver agreements were excellent or good with regard to image quality and final diagnoses. For the BM1 and BMI2 groups, ULD-CT provided an acceptable image quality and exhibited a diagnostic accuracy similar to that of LD-CT. These findings suggest that it is a useful diagnostic tool for patients with chronic LBP who exhibit a BMI of <25 kg/m 2 . (orig.)

  9. Cardiac autonomic tone during trandolapril-irbesartan low-dose combined therapy in hypertension: a pilot project.

    Science.gov (United States)

    Franchi, F; Lazzeri, C; Foschi, M; Tosti-Guerra, C; Barletta, G

    2002-08-01

    Pharmacological and clinical studies on the effects of angiotensin-converting enzyme (ACE) inhibitors support the idea of a central role played Angiotensin II which is able to cause cardiovascular and renal diseases also independently of its blood pressure elevating effects. The present investigation was aimed at evaluating the effect(s) of three different pharmacological regimens on both blood pressure and sympathetic drive in uncomplicated essential hypertension, by means of blood pressure laboratory measurements and ambulatory monitoring, 24-h heart rate variability and plasma noradrenaline levels. Thus, an ACE-inhibitor monotherapy (trandolapril, 2 mg/day), an AT(1)-receptor antagonist monotherapy (irbesartan, 300 mg/day), their low-dose combination (0.5 mg/day plus 150 mg/day, respectively) and placebo were given, in a randomised, single-blind, crossover fashion for a period of 3 weeks each to 12 mild essential hypertensives. Power spectral analysis (short recordings) and noradrenaline measurements were also performed in the supine position and after a postural challenge (60 degrees head-up tilting test: HUT). The low-dose combination therapy induced the greatest reduction in LF component and in LF/HF ratio, both in the resting and tilted positions, as well as in blood pressure. However, the physiological autonomic response to HUT was maintained. Noradrenaline plasma levels were lower after the combined therapy than after each drug alone. Our data demonstrate that in mild and uncomplicated essential hypertension, the chronic low-dose combination therapy with an ACE-inhibitor and an AT(1)-antagonist is more effective than the recommended full-dose monotherapy with either drug in influencing the autonomic regulation of the heart, suggesting a relative reduction in sympathetic drive both at cardiac and systemic levels.

  10. 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)

  11. 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

  12. 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.

  13. Photoprotective effect of a psoralen-UVA-induced tan

    International Nuclear Information System (INIS)

    Gschnait, F.; Brenner, W.; Wolff, K.

    1978-01-01

    To determine whether a tan produced by 8-MOP and UVA protects from subsequent solar light irradiation, volunteers were irradiated with unfiltered Xenon arc light before and 10 days after a 1 week's course of four 8-MOP-UVA treatments. Evaluation of the minimal erythema doses and of histological changes before and after 8-MOP-UVA treatment revealed that the 8-MOP-UVA induced tan protected against the erythemogenic and cell damaging effects of Xenon arc light. Unscheduled repair DNA synthesis, used as a measure for UVB-induced DNA damage and repair, was also investigated in skin irradiated with the Xenon arc before and after 8-MOP-UVA induced tanning. Both the number of grains per sparse labeled cell and the number of sparse labeled cells per 1000 cells, were found to be significantly lower in tanned skin; taking decreased unscheduled repair DNA synthesis as a measure for decreased DNA-damage, these findings also demonstrate a photoprotective effect of the 8-MOP-UVA induced tan. (orig.) [de

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.)

  1. 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...

  2. 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.

  3. Comparison of thermoradiosensitization in two human melanoma cell lines and one fibroblast cell line by concurrent mild hyperthermia and low-dose-rate irradiation

    International Nuclear Information System (INIS)

    Raaphorst, G.P.; Bussey, A.; Heller, D.P.; Ng, C.E.

    1994-01-01

    Two human melanoma cell lines, one radioresistant (Sk-MEL-3) and one radiosensitive (HT-144), and a normal human fibroblast line (AG1522) were evaluated for thermoradiosensitization of low-dose-rate irradiation by concurrent mild hyperthermia (39-41 degrees C). None of the cell lines expressed chronic thermotolerance during heating at 39-41 degrees C. The SK-MEL-3 cells were the most heat sensitive, while AG1522 and HT-144 cells had the same sensitivity at 39 and 40 degrees C but HT-144 cells were more sensitive at 41 degrees C. All cell lines expressed thermal enhancement of radiosensitivity with heating during irradiation which increased with heating temperature. The SK-MEL-3 cells, which were the most resistant to radiation and demonstrated the greatest repair of sublethal damage (SLD) during low-dose-rate irradiation, had the greatest thermal enhancement of radiosensitivity, while the HT144 cells, which were the most sensitive and expressed little repair of SLD during low-dose-rate irradiation, had the smallest thermal enhancement of radiosensitivity. These data show that concurrent mild hyperthermia during low-dose-rate irradiation may be most efficacious in radiation-resistant tumor cells which express resistance through an enhanced capacity for repair of SLD. 24 refs., 5 figs., 1 tab

  4. 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)

  5. 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)

  6. 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.

  7. 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...

  8. 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)

  9. 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

  10. 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.

  11. 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)

  12. Experimental investigation of combined blastomogenic effect of chronic low-dose ionizing radiation and chemical carcinogen

    International Nuclear Information System (INIS)

    Poruba, G. M.

    2001-01-01

    Exposure of high-and low cancer lines of mice in the contaminated area of Cherikov district in Gomel Region (dose rate 380-400 mR/h) for 120 days caused intensification of urethane-induced carcinogenesis in the lung of the high-cancer mouse line and did not exert a modifying effect on urethane pulmonary carcinogenesis in low-cancer animals. The findings indicate to genetic determination of body sensitivity to a complex blastomogenic effect of the factors studied (authors)

  13. Ultra-low-dose CT imaging of the thorax: decreasing the radiation dose by one order of magnitude

    International Nuclear Information System (INIS)

    Lambert, Lukas; Banerjee, Rohan; Votruba, Jiri; El-Lababidi, Nabil; Zeman, Jiri

    2016-01-01

    Computed tomography (CT) is an indispensable tool for imaging of the thorax and there is virtually no alternative without associated radiation burden. The authors demonstrate ultra-low-dose CT of the thorax in three interesting cases. In an 18-y-old girl with rheumatoid arthritis, CT of the thorax identified alveolitis in the posterior costophrenic angles (radiation dose = 0.2 mSv). Its resolution was demonstrated on a follow-up scan (4.2 mSv) performed elsewhere. In an 11-y-old girl, CT (0.1 mSv) showed changes of the right collar bone consistent with chronic recurrent multifocal osteomyelitis. CT (0.1 mSv) of a 9-y-old girl with mucopolysaccharidosis revealed altogether three hamartomas, peribronchial infiltrate, and spine deformity. In some indications, the radiation dose from CT of the thorax can approach that of several plain radiographs. This may help the pediatrician in deciding whether 'gentle' ultra-low-dose CT instead of observation or follow-up radiographs will alleviate the uncertainty of the diagnosis with little harm to the child. (author)

  14. 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.

  15. 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.

  16. 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.

  17. 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)

  18. 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)

  19. Pharmacokinetics of orally administered low-dose rapamycin in healthy dogs.

    Science.gov (United States)

    Larson, Jeanne C; Allstadt, Sara D; Fan, Timothy M; Khanna, Chand; Lunghofer, Paul J; Hansen, Ryan J; Gustafson, Daniel L; Legendre, Alfred M; Galyon, Gina D; LeBlanc, Amy K; Martin-Jimenez, Tomas

    2016-01-01

    To determine the pharmacokinetics of orally administered rapamycin in healthy dogs. 5 healthy purpose-bred hounds. The study consisted of 2 experiments. In experiment 1, each dog received rapamycin (0.1 mg/kg, PO) once; blood samples were obtained immediately before and at 0.5, 1, 2, 4, 6, 12, 24, 48, and 72 hours after administration. In experiment 2, each dog received rapamycin (0.1 mg/kg, PO) once daily for 5 days; blood samples were obtained immediately before and at 3, 6, 24, 27, 30, 48, 51, 54, 72, 75, 78, 96, 96.5, 97, 98, 100, 102, 108, 120, 144, and 168 hours after the first dose. Blood rapamycin concentration was determined by a validated liquid chromatography-tandem mass spectrometry assay. Pharmacokinetic parameters were determined by compartmental and noncompartmental analyses. Mean ± SD blood rapamycin terminal half-life, area under the concentration-time curve from 0 to 48 hours after dosing, and maximum concentration were 38.7 ± 12.7 h, 140 ± 23.9 ng•h/mL, and 8.39 ± 1.73 ng/mL, respectively, for experiment 1, and 99.5 ± 89.5 h, 126 ± 27.1 ng•h/mL, and 5.49 ± 1.99 ng/mL, respectively, for experiment 2. Pharmacokinetic parameters for rapamycin after administration of 5 daily doses differed significantly from those after administration of 1 dose. Results indicated that oral administration of low-dose (0.1 mg/kg) rapamycin to healthy dogs achieved blood concentrations measured in nanograms per milliliter. The optimal dose and administration frequency of rapamcyin required to achieve therapeutic effects in tumor-bearing dogs, as well as toxicity after chronic dosing, need to be determined.

  20. Pharmacokinetics of orally administered low-dose rapamycin in healthy dogs: A pilot study

    Science.gov (United States)

    Larson, Jeanne C.; Allstadt, Sara D.; Fan, Timothy M.; Khanna, Chand; Lunghofer, Paul J.; Hansen, Ryan J.; Gustafson, Daniel L.; Legendre, Alfred M.; Galyon, Gina D.; LeBlanc, Amy K.; Martin-Jimenez, Tomas

    2017-01-01

    Objective To determine the pharmacokinetics of orally administered rapamycin in healthy dogs. Animals 5 healthy purpose-bred hounds. Procedures The study consisted of 2 experiments. In experiment 1, each dog received rapamycin (0.1 mg/kg, PO) once; blood samples were obtained immediately before and at 0.5, 1, 2, 4, 6, 12, 24, 48, and 72 hours after administration. In experiment 2, each dog received (0.1 mg/kg, PO) once daily for 5 days; blood samples were obtained immediately before and at 3, 6, 24, 27, 30, 48, 51, 54, 72, 75, 78, 96, 96.5, 97, 98, 100, 102, 108, 120, 144, and 168 hours after the first dose. Blood rapamycin concentration was determined by a validated liquid chromatography-tandem mass spectrometry assay. Pharmacokinetic parameters were determined by compartmental and non-compartmental analyses. Results Mean ± SD blood rapamycin terminal half-life, area under the concentration-time curve from 0 to 48 hours after dosing, and maximum concentration were 38.7 ± 12.7 h, 140 ± 23.9 ng•h/mL, and 8.39 ± 1.73 ng/mL, respectively, for experiment 1, and 99.5 ± 89.5 h, 126 ± 27.1 ng•h/mL, and 5.49 ± 1.99 ng/mL, respectively, for experiment 2. Pharmacokinetic parameters for rapamycin after administration of 5 daily doses differed significantly from those after administration of 1 dose. Conclusions and Clinical Relevance Results indicated that oral administration of low-dose (0.1 mg/kg) rapamycin to healthy dogs achieved blood concentrations measured in ng/mL. The optimal dose and administration frequency of rapamcyin required to achieve therapeutic effects in tumor-bearing dogs, as well as toxicity after chronic dosing, needs to be determined. PMID:26709938

  1. Is there a way to resolve the controversy on low dose effects?

    International Nuclear Information System (INIS)

    Higson, D.J.

    2002-01-01

    The controversy which is addressed in this paper is whether there are risks or benefits to health from exposure to low levels of ionising radiation or, indeed, whether there are any significant health effects at all. The background to this controversy was outlined in 1998 in the report of a Task Group on Low Dose Effects, convened by the International Nuclear Societies Council (INSC). For the purpose of the INSC report, low levels of radiation were defined as acute doses less than 10 mSv and chronic dose rates less than 20 mSv per year. The INSC Task Group itself concluded that, either there is no risk, or there may be health benefits from such exposures. The scientific aspects of the matter were reviewed by the author in 2001 at the IRPA Regional Congress on Radiation Protection in Central Europe, in Dubrovnik, and are summarised in the next section of this paper. In Dubrovnik, the author concluded that there is at least as much evidence of beneficial health effects as harmful effects from low level radiation. Controversy on the biological effects of low level radiation continues to be polarised to an extent which should be considered unacceptable in a rational community, and it is aggravated by the multiplicity of different viewpoints from which to consider the information available on this subject. These viewpoints include not only the scientific and regulatory positions, but also public and political perceptions, and the news media; and they lead to a wide variety of views, each of which is considered to be legitimate by most of those who adopt it

  2. 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....

  3. Radioimmunoanalysis of the immune response and tissue lipoperoxidation of rats for low doses contaminated with tritiated water

    International Nuclear Information System (INIS)

    Bejan, A.; Turcu, Gr.

    1996-01-01

    The paper presents the evaluation of the humoral immune response and liver and kidney lipoperoxidation on rats acutely and chronically contaminated with low doses of tritiated water (HTO). The contamination doses for both situations were 0.5 cSv, 5 cSv and 10 cSv. By humoral immune response analysis we mean the measurement, through a radioimmunoanalysis (RIA) method, of the two intrinsic parameters of an antiserum, that is, the mean antibodies concentration and the mean antibodies affinity constant. We followed the liver and kidney lipidic peroxidation through malondialdehyde (MDA) formation assayed by the thiobarbituric acid (TBA) reaction. The humoral immune response and lipoperoxidation have been compared with the response of an uncontaminated group by the Student t test. (author). 17 refs., 2 tabs

  4. Very Low-Dose Risperidone in First-Episode Psychosis: A Safe and Effective Way to Initiate Treatment

    Directory of Open Access Journals (Sweden)

    Patrick D. McGorry

    2011-01-01

    Full Text Available Patients experiencing a first psychotic episode have high rates of extrapyramidal symptoms (EPSs when treated with the doses of neuroleptics used in multiepisode or chronic schizophrenia. There is some evidence that lower doses may be equally, if not more, effective but less toxic in this population. Here, we report the results of a biphasic open label trial designed to assess the efficacy, safety, and tolerability of low-dose (2–4 mg/day risperidone treatment in a group of 96 first-episode nonaffective psychosis patients. At the end of the trial, 62% of patients met the response criteria although approximately 80% had achieved a response at some time during the study. Reports of EPS remained low, and there were no dystonic reactions. We conclude that even at a dose of 2 mg/day, risperidone was highly effective in reducing acute symptomatology in a real world sample of young first-episode psychosis patients.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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

  10. 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.)

  11. 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)

  12. 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)

  13. 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)

  14. 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

  15. UVA Irradiation of Dysplastic Keratinocytes: Oxidative Damage versus Antioxidant Defense

    Science.gov (United States)

    Nechifor, Marina T.; Niculiţe, Cristina M.; Urs, Andreea O.; Regalia, Teodor; Mocanu, Mihaela; Popescu, Alexandra; Manda, Gina; Dinu, Diana; Leabu, Mircea

    2012-01-01

    UVA affects epidermal cell physiology in a complex manner, but the harmful effects have been studied mainly in terms of DNA damage, mutagenesis and carcinogenesis. We investigated UVA effects on membrane integrity and antioxidant defense of dysplastic keratinocytes after one and two hours of irradiation, both immediately after exposure, and 24 h post-irradiation. To determine the UVA oxidative stress on cell membrane, lipid peroxidation was correlated with changes in fatty acid levels. Membrane permeability and integrity were assessed by propidium iodide staining and lactate dehydrogenase release. The effects on keratinocyte antioxidant protection were investigated in terms of catalase activity and expression. Lipid peroxidation increased in an exposure time-dependent manner. UVA exposure decreased the level of polyunsaturated fatty acids, which gradually returned to its initial value. Lactate dehydrogenase release showed a dramatic loss in membrane integrity after 2 h minimum of exposure. The cell ability to restore membrane permeability was noted at 24 h post-irradiation (for one hour exposure). Catalase activity decreased in an exposure time-dependent manner. UVA-irradiated dysplastic keratinocytes developed mechanisms leading to cell protection and survival, following a non-lethal exposure. The surviving cells gained an increased resistance to apoptosis, suggesting that their pre-malignant status harbors an abnormal ability to control their fate. PMID:23222638

  16. Genotoxic effects of high dose rate X-ray and low dose rate gamma radiation in ApcMin/+ mice.

    Science.gov (United States)

    Graupner, Anne; Eide, Dag M; Brede, Dag A; Ellender, Michele; Lindbo Hansen, Elisabeth; Oughton, Deborah H; Bouffler, Simon D; Brunborg, Gunnar; Olsen, Ann Karin

    2017-10-01

    Risk estimates for radiation-induced cancer in humans are based on epidemiological data largely drawn from the Japanese atomic bomb survivor studies, which received an acute high dose rate (HDR) ionising radiation. Limited knowledge exists about the effects of chronic low dose rate (LDR) exposure, particularly with respect to the application of the dose and dose rate effectiveness factor. As part of a study to investigate the development of colon cancer following chronic LDR vs. acute HDR radiation, this study presents the results of genotoxic effects in blood of exposed mice. CBAB6 F1 Apc +/+ (wild type) and Apc Min/+ mice were chronically exposed to estimated whole body absorbed doses of 1.7 or 3.2 Gy 60 Co-γ-rays at a LDR (2.2 mGy h -1 ) or acutely exposed to 2.6 Gy HDR X-rays (1.3 Gy min -1 ). Genotoxic endpoints assessed in blood included chromosomal damage (flow cytometry based micronuclei (MN) assay), mutation analyses (Pig-a gene mutation assay), and levels of DNA lesions (Comet assay, single-strand breaks (ssb), alkali labile sites (als), oxidized DNA bases). Ionising radiation (ca. 3 Gy) induced genotoxic effects dependent on the dose rate. Chromosomal aberrations (MN assay) increased 3- and 10-fold after chronic LDR and acute HDR, respectively. Phenotypic mutation frequencies as well as DNA lesions (ssb/als) were modulated after acute HDR but not after chronic LDR. The Apc Min/+ genotype did not influence the outcome in any of the investigated endpoints. The results herein will add to the scant data available on genotoxic effects following chronic LDR of ionising radiation. Environ. Mol. Mutagen. 58:560-569, 2017. © 2017 The Authors Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society. © 2017 The Authors Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society.

  17. Efficacy of low-dose cinacalcet on alternate days for the treatment of secondary hyperparathyroidism in hemodialysis patients: a single-center study

    Directory of Open Access Journals (Sweden)

    Gojaseni P

    2017-02-01

    Full Text Available Pongsathorn Gojaseni, Dolnapa Pattarathitinan, Anutra Chittinandana Division of Nephrology, Department of Medicine, Bhumibol Adulyadej Hospital, Directorate of Medical Services, Royal Thai Air Force, Bangkok, Thailand Introduction: Cinacalcet is effective in reducing serum parathyroid hormone (PTH in patients with secondary hyperparathyroidism (HPT. This study focused on testing whether a prescription of low-dose cinacalcet on alternate days could be an option for treatment of secondary HPT.Materials and methods: A retrospective clinical study was conducted on chronic maintenance hemodialysis patients. Patients with secondary HPT who received cinacalcet at a starting dose of 25 mg on alternate days were reviewed (low-dose group. Patients who were being treated with a standard dose of cinacalcet in the same period of time were selected as the control group. The primary outcome was difference in the percentage of patients achieving >30% reduction of intact parathyroid hormone (iPTH levels at 16 weeks. The changes of serum iPTH and other biochemical data were also tested.Results: A total of 30 patients (16 low doses and 14 controls took part in the study. Baseline iPTH levels in the low-dose and control group were 1,065.9±477.7 and 1,214.1±497.6 pg/mL, respectively (p=0.413. The analysis showed that the percentage of patients who achieved the primary outcome showed little or no difference (33.3% in the low-dose group compared with 38.5% in the control group, p=1.0. Serum iPTH reduction during 16 weeks of study period in the low-dose and control group was 253.5±316.1 and 243.4±561.3 pg/mL, respectively (p=0.957. There was no difference in the adverse events between both groups.Conclusion: Among patients with secondary HPT, initial treatment with cinacalcet 25 mg on alternate days can decrease serum PTH levels. The role of low-dose cinacalcet in secondary HPT should be further determined in large-scale, randomized controlled trials. Keywords

  18. Differential responses to high- and low-dose ultraviolet-B stress in tobacco Bright Yellow-2 cells

    Science.gov (United States)

    Takahashi, Shinya; Kojo, Kei H.; Kutsuna, Natsumaro; Endo, Masaki; Toki, Seiichi; Isoda, Hiroko; Hasezawa, Seiichiro

    2015-01-01

    Ultraviolet (UV)-B irradiation leads to DNA damage, cell cycle arrest, growth inhibition, and cell death. To evaluate the UV-B stress–induced changes in plant cells, we developed a model system based on tobacco Bright Yellow-2 (BY-2) cells. Both low-dose UV-B (low UV-B: 740 J m−2) and high-dose UV-B (high UV-B: 2960 J m−2) inhibited cell proliferation and induced cell death; these effects were more pronounced at high UV-B. Flow cytometry showed cell cycle arrest within 1 day after UV-B irradiation; neither low- nor high-UV-B–irradiated cells entered mitosis within 12 h. Cell cycle progression was gradually restored in low-UV-B–irradiated cells but not in high-UV-B–irradiated cells. UV-A irradiation, which activates cyclobutane pyrimidine dimer (CPD) photolyase, reduced inhibition of cell proliferation by low but not high UV-B and suppressed high-UV-B–induced cell death. UV-B induced CPD formation in a dose-dependent manner. The amounts of CPDs decreased gradually within 3 days in low-UV-B–irradiated cells, but remained elevated after 3 days in high-UV-B–irradiated cells. Low UV-B slightly increased the number of DNA single-strand breaks detected by the comet assay at 1 day after irradiation, and then decreased at 2 and 3 days after irradiation. High UV-B increased DNA fragmentation detected by the terminal deoxynucleotidyl transferase dUTP nick end labeling assay 1 and 3 days after irradiation. Caffeine, an inhibitor of ataxia telangiectasia mutated (ATM) and ataxia telangiectasia and Rad3-related (ATR) checkpoint kinases, reduced the rate of cell death in high-UV-B–irradiated cells. Our data suggest that low-UV-B–induced CPDs and/or DNA strand-breaks inhibit DNA replication and proliferation of BY-2 cells, whereas larger contents of high-UV-B–induced CPDs and/or DNA strand-breaks lead to cell death. PMID:25954287

  19. 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.

  20. 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.)

  1. 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)

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Changes of chromosome aberration rate and micronucleus frequency along with accumulated dose in continuously irradiated mice with a low dose rate of γ-rays

    International Nuclear Information System (INIS)

    Tanaka, Kimio; Izumi, Jun; Yanai, Takanori; Ichinohe, Kazuaki; Matsumoto, Tsuneya

    2003-01-01

    Chromosome aberrations in chronically exposed workers in nuclear facilities and medical radiologists have been reported. However chronological change of chromosome aberration rates along with accumulated dose has not been well studied. Chromosome aberrations and micronuclei in spleen lymphocytes were observed serially in mice continuously irradiated with a low dose rate of 20 mGy/day up to 400 days. Chromosome aberration rates were rapidly increased to 11.1% at 1 Gy, while micronucleus incidence increased at 5 Gy. After these doses their increase rates were saturated. Micronucleus incidence in bone marrow erythroblasts was higher than in spleen cells. These chronological changes of cytogenetic aberrations seem to be induced through a balance between developments of chromosome aberrations and micronuclei, and life span of spleen lymphocytes. These results will be helpful for risk assessment in low dose rate radiation exposure. (author)

  8. Effect of low dose gamma radiation on stamen-hairs of different clones of Tradescantia presenting variability in the frequency of spontaneous mutations

    International Nuclear Information System (INIS)

    Takahashi, C.S.

    1976-01-01

    Changes in the frequency of spontaneous somatic mutations were studied for three different clones of Tradescantia heterozygotes for flower and stamen-hair color keeping them under controlled or natural conditions in order to verify the effect of different environmental conditions on the different genotypes. The effect of inflorescence age on the variation of spontaneous mutations was studied choosing young and old inflorescences of a same plant. Low dose irradiation experiments were carried out with those clones to elucidate the radiation effects on the clones presenting changes in the frequency of spontaneous mutations. The chronic-and acute irradiation effects of low dose irradiation of the stamen-hair of Tradescantia were also studied. Results are discussed. (M.A.) [pt

  9. 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