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Sample records for attenuates multiple low-dose

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

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    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.

  2. Multiple low-dose radiation prevents type 2 diabetes-induced renal damage through attenuation of dyslipidemia and insulin resistance and subsequent renal inflammation and oxidative stress.

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    Minglong Shao

    Full Text Available Dyslipidemia and lipotoxicity-induced insulin resistance, inflammation and oxidative stress are the key pathogeneses of renal damage in type 2 diabetes. Increasing evidence shows that whole-body low dose radiation (LDR plays a critical role in attenuating insulin resistance, inflammation and oxidative stress.The aims of the present study were to investigate whether LDR can prevent type 2 diabetes-induced renal damage and the underlying mechanisms.Mice were fed with a high-fat diet (HFD, 40% of calories from fat for 12 weeks to induce obesity followed by a single intraperitoneal injection of streptozotocin (STZ, 50 mg/kg to develop a type 2 diabetic mouse model. The mice were exposed to LDR at different doses (25, 50 and 75 mGy for 4 or 8 weeks along with HFD treatment. At each time-point, the kidney weight, renal function, blood glucose level and insulin resistance were examined. The pathological changes, renal lipid profiles, inflammation, oxidative stress and fibrosis were also measured.HFD/STZ-induced type 2 diabetic mice exhibited severe pathological changes in the kidney and renal dysfunction. Exposure of the mice to LDR for 4 weeks, especially at 50 and 75 mGy, significantly improved lipid profiles, insulin sensitivity and protein kinase B activation, meanwhile, attenuated inflammation and oxidative stress in the diabetic kidney. The LDR-induced anti-oxidative effect was associated with up-regulation of renal nuclear factor E2-related factor-2 (Nrf-2 expression and function. However, the above beneficial effects were weakened once LDR treatment was extended to 8 weeks.These results suggest that LDR exposure significantly prevented type 2 diabetes-induced kidney injury characterized by renal dysfunction and pathological changes. The protective mechanisms of LDR are complicated but may be mainly attributed to the attenuation of dyslipidemia and the subsequent lipotoxicity-induced insulin resistance, inflammation and oxidative stress.

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

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    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

  4. Low-dose multiple-information retrieval algorithm for X-ray grating-based imaging

    International Nuclear Information System (INIS)

    Wang Zhentian; Huang Zhifeng; Chen Zhiqiang; Zhang Li; Jiang Xiaolei; Kang Kejun; Yin Hongxia; Wang Zhenchang; Stampanoni, Marco

    2011-01-01

    The present work proposes a low dose information retrieval algorithm for X-ray grating-based multiple-information imaging (GB-MII) method, which can retrieve the attenuation, refraction and scattering information of samples by only three images. This algorithm aims at reducing the exposure time and the doses delivered to the sample. The multiple-information retrieval problem in GB-MII is solved by transforming a nonlinear equations set to a linear equations and adopting the nature of the trigonometric functions. The proposed algorithm is validated by experiments both on conventional X-ray source and synchrotron X-ray source, and compared with the traditional multiple-image-based retrieval algorithm. The experimental results show that our algorithm is comparable with the traditional retrieval algorithm and especially suitable for high Signal-to-Noise system.

  5. Radiation-induced attenuation in polarization maintaining fibers: low dose rate response, stress, and materials effects

    International Nuclear Information System (INIS)

    Gingerich, M.E.; Friebele, E.J.; Hickey, S.J.; Brambani, L.A.; Onstott, J.R.

    1989-01-01

    The loss induced in polarization-maintaining (PM) fibers by low dose rate <0.01 Gy/h, where 1 Gy = 100 rads(Si) radiation exposure has been found to vary from <0.4 to ∼6 dB/km-10 Gy, depending on the wavelength of measurement and the fiber. Correlations have been established between low dose rate response and the ''permanent'' induced loss determined by fitting the recovery of the induced loss following high dose rate exposure to nth-order kinetics. Using this technique, both 0.85- and 1.3-μm PM fibers have been found which show virtually no permanent incremental loss and would therefore appear to be resistant to low dose rate radiation environments. The asymmetric stress inherent in PM fibers has been shown to reduce the permanent induced loss, while the recovery of the radiation-induced attenuation was found to be enhanced in fibers with Ge-F-doped silica clads

  6. Ultra-low dose CT attenuation correction for PET/CT: analysis of sparse view data acquisition and reconstruction algorithms

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    Rui, Xue; Cheng, Lishui; Long, Yong; Fu, Lin; Alessio, Adam M.; Asma, Evren; Kinahan, Paul E.; De Man, Bruno

    2015-01-01

    For PET/CT systems, PET image reconstruction requires corresponding CT images for anatomical localization and attenuation correction. In the case of PET respiratory gating, multiple gated CT scans can offer phase-matched attenuation and motion correction, at the expense of increased radiation dose. We aim to minimize the dose of the CT scan, while preserving adequate image quality for the purpose of PET attenuation correction by introducing sparse view CT data acquisition. Methods We investigated sparse view CT acquisition protocols resulting in ultra-low dose CT scans designed for PET attenuation correction. We analyzed the tradeoffs between the number of views and the integrated tube current per view for a given dose using CT and PET simulations of a 3D NCAT phantom with lesions inserted into liver and lung. We simulated seven CT acquisition protocols with {984, 328, 123, 41, 24, 12, 8} views per rotation at a gantry speed of 0.35 seconds. One standard dose and four ultra-low dose levels, namely, 0.35 mAs, 0.175 mAs, 0.0875 mAs, and 0.04375 mAs, were investigated. Both the analytical FDK algorithm and the Model Based Iterative Reconstruction (MBIR) algorithm were used for CT image reconstruction. We also evaluated the impact of sinogram interpolation to estimate the missing projection measurements due to sparse view data acquisition. For MBIR, we used a penalized weighted least squares (PWLS) cost function with an approximate total-variation (TV) regularizing penalty function. We compared a tube pulsing mode and a continuous exposure mode for sparse view data acquisition. Global PET ensemble root-mean-squares-error (RMSE) and local ensemble lesion activity error were used as quantitative evaluation metrics for PET image quality. Results With sparse view sampling, it is possible to greatly reduce the CT scan dose when it is primarily used for PET attenuation correction with little or no measureable effect on the PET image. For the four ultra-low dose levels

  7. Ultra-low dose CT attenuation correction for PET/CT

    International Nuclear Information System (INIS)

    Xia Ting; Kinahan, Paul E; Alessio, Adam M; De Man, Bruno; Manjeshwar, Ravindra; Asma, Evren

    2012-01-01

    A challenge for positron emission tomography/computed tomography (PET/CT) quantitation is patient respiratory motion, which can cause an underestimation of lesion activity uptake and an overestimation of lesion volume. Several respiratory motion correction methods benefit from longer duration CT scans that are phase matched with PET scans. However, even with the currently available, lowest dose CT techniques, extended duration cine CT scans impart a substantially high radiation dose. This study evaluates methods designed to reduce CT radiation dose in PET/CT scanning. We investigated selected combinations of dose reduced acquisition and noise suppression methods that take advantage of the reduced requirement of CT for PET attenuation correction (AC). These include reducing CT tube current, optimizing CT tube voltage, adding filtration, CT sinogram smoothing and clipping. We explored the impact of these methods on PET quantitation via simulations on different digital phantoms. CT tube current can be reduced much lower for AC than that in low dose CT protocols. Spectra that are higher energy and narrower are generally more dose efficient with respect to PET image quality. Sinogram smoothing could be used to compensate for the increased noise and artifacts at radiation dose reduced CT images, which allows for a further reduction of CT dose with no penalty for PET image quantitation. When CT is not used for diagnostic and anatomical localization purposes, we showed that ultra-low dose CT for PET/CT is feasible. The significant dose reduction strategies proposed here could enable respiratory motion compensation methods that require extended duration CT scans and reduce radiation exposure in general for all PET/CT imaging. (paper)

  8. Ultra-low dose CT attenuation correction for PET/CT

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    Xia, Ting; Alessio, Adam M.; De Man, Bruno; Manjeshwar, Ravindra; Asma, Evren; Kinahan, Paul E.

    2012-01-01

    A challenge for PET/CT quantitation is patient respiratory motion, which can cause an underestimation of lesion activity uptake and an overestimation of lesion volume. Several respiratory motion correction methods benefit from longer duration CT scans that are phase matched with PET scans. However, even with the currently-available, lowest dose CT techniques, extended duration CINE CT scans impart a substantially high radiation dose. This study evaluates methods designed to reduce CT radiation dose in PET/CT scanning. Methods We investigated selected combinations of dose reduced acquisition and noise suppression methods that take advantage of the reduced requirement of CT for PET attenuation correction (AC). These include reducing CT tube current, optimizing CT tube voltage, adding filtration, CT sinogram smoothing and clipping. We explored the impact of these methods on PET quantitation via simulations on different digital phantoms. Results CT tube current can be reduced much lower for AC than that in low dose CT protocols. Spectra that are higher energy and narrower are generally more dose efficient with respect to PET image quality. Sinogram smoothing could be used to compensate for the increased noise and artifacts at radiation dose reduced CT images, which allows for a further reduction of CT dose with no penalty for PET image quantitation. Conclusion When CT is not used for diagnostic and anatomical localization purposes, we showed that ultra-low dose CT for PET/CT is feasible. The significant dose reduction strategies proposed here could enable respiratory motion compensation methods that require extended duration CT scans and reduce radiation exposure in general for all PET/CT imaging. PMID:22156174

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

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    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

  10. Ultra-low Dose CT for Attenuation Correction of 82Rb Cardiac PET

    DEFF Research Database (Denmark)

    Sørensen, Maria Balshøj; Bouchelouche, Kirsten; Tolbod, Lars Poulsen

    Aim: Myocardial perfusion imaging (MPI) using cardiac PET with tracers like 82Rb and 15O-water is substantially lower in radiation dose than classic MIBI-based SPECT. However, for cardiac PET, the dose contribution of CT for attenuation correction (CTAC) is typically 20-30% of the total dose....... To reduce the total radiation dose of cardiac PET further, we set out to examine if the use of ultra-low dose CTAC (UL-CTAC) would affect the accuracy of the quantitative parameters related to MPI. Furthermore, we examined whether the low quality of the UL-CTAC would affect the technologist’s ability...... to perform manual adjustment for misalignment between PET and CTAC. The CT reconstruction algorithm Q.AC was used to improve quality and consistency of the CTAC. Method: 23 consecutive clinical patients (BMI: 26.9 [range: 15.4-38.8]) referred for 82Rb PET rest and stress imaging were included in the study...

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

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    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.

  13. 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)

  14. Attenuation of 10 MeV electron beam energy to achieve low doses does not affect Salmonella spp. inactivation kinetics

    International Nuclear Information System (INIS)

    Hieke, Anne-Sophie Charlotte; Pillai, Suresh D.

    2015-01-01

    The effect of attenuating the energy of a 10 MeV electron beam on Salmonella inactivation kinetics was investigated. No statistically significant differences were observed between the D 10 values of either Salmonella 4,[5],12:i:- or a Salmonella cocktail (S. 4,[5],12:i:-, Salmonella Heidelberg, Salmonella Newport, Salmonella Typhimurium, Salmonella) when irradiated with either a non-attenuated 10 MeV eBeam or an attenuated 10 MeV eBeam (~2.9±0.22 MeV). The results show that attenuating the energy of a 10 MeV eBeam to achieve low doses does not affect the inactivation kinetics of Salmonella spp. when compared to direct 10 MeV eBeam irradiation. - Highlights: • 10 MeV eBeam energy was attenuated to 2.9±0.22 MeV using HDPE sheets. • Attenuation of eBeam energy does not affect the inactivation kinetics of Salmonella. • Microbial inactivation is independent of eBeam energy in the range of 3–10 MeV

  15. Low-dose biplanar skeletal survey versus digital skeletal survey in multiple myeloma

    International Nuclear Information System (INIS)

    Boutry, Nathalie; Dutouquet, Bastien; Cotten, Anne; Leleu, Xavier; Vieillard, Marie-Helene; Duhamel, Alain

    2013-01-01

    To evaluate the low-dose biplanar (LDB) skeletal survey (SS) for the assessment of focal bone involvement in patients with multiple myeloma (MM) as compared with digital SS and to compare the two techniques in terms of image quality, patient comfort and radiation exposure. Fifty-six consecutive patients with newly diagnosed or first relapsed MM underwent LDB and digital SS on the same day. These were assessed by two radiologists for the detection of focal bone lesions. In the case of discordance, whole-body MR imaging was performed. Image quality, patient comfort and radiation dose were also assessed. Fifty-six patients (M:30, F:26, mean age, 62 years) with newly diagnosed (n = 21) or first relapse MM (n = 35) were enrolled. A total of 473 bone lesions in 46 patients (82 %) were detected. Out of that total, digital SS detected significantly more lesions than LDB SS (451 [95.35 %] versus 467 [98.73 %]), especially in osteopenic and obese patients. Overall patient satisfaction was greater with LDB SS (48.6 %) compared with digital SS (2.7 %). The radiation dose was significantly reduced (by a factor of 7.8) with the LDB X-ray device. Low-dose biplanar skeletal surveys cannot replace digital SS in all patients suffering from multiple myeloma. (orig.)

  16. Low-dose biplanar skeletal survey versus digital skeletal survey in multiple myeloma

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    Boutry, Nathalie [University Hospital of Jeanne de Flandre and University of Lille 2, Departments of Pediatric and Musculoskeletal Imaging, Lille (France); University Hospital of Jeanne de Flandre and University of Lille 2, Department of Pediatric Imaging, Lille (France); Hopital Jeanne de Flandre, Service de Radiopediatrie, Lille (France); Dutouquet, Bastien; Cotten, Anne [University Hospital of Roger Salengro and University of Lille 2, Department of Musculoskeletal Imaging, Lille (France); Leleu, Xavier [University Hospital of Claude Huriez and University of Lille 2, Clinical Hematology Department, Lille (France); Vieillard, Marie-Helene [University Hospital of Roger Salengro and University of Lille 2, Rheumatology Department, Lille (France); Duhamel, Alain [University of Lille 2, Department of Medical Statistics, Lille (France)

    2013-08-15

    To evaluate the low-dose biplanar (LDB) skeletal survey (SS) for the assessment of focal bone involvement in patients with multiple myeloma (MM) as compared with digital SS and to compare the two techniques in terms of image quality, patient comfort and radiation exposure. Fifty-six consecutive patients with newly diagnosed or first relapsed MM underwent LDB and digital SS on the same day. These were assessed by two radiologists for the detection of focal bone lesions. In the case of discordance, whole-body MR imaging was performed. Image quality, patient comfort and radiation dose were also assessed. Fifty-six patients (M:30, F:26, mean age, 62 years) with newly diagnosed (n = 21) or first relapse MM (n = 35) were enrolled. A total of 473 bone lesions in 46 patients (82 %) were detected. Out of that total, digital SS detected significantly more lesions than LDB SS (451 [95.35 %] versus 467 [98.73 %]), especially in osteopenic and obese patients. Overall patient satisfaction was greater with LDB SS (48.6 %) compared with digital SS (2.7 %). The radiation dose was significantly reduced (by a factor of 7.8) with the LDB X-ray device. Low-dose biplanar skeletal surveys cannot replace digital SS in all patients suffering from multiple myeloma. (orig.)

  17. Systemic low-dose aspirin and clopidogrel independently attenuate reflex cutaneous vasodilation in middle-aged humans.

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    Holowatz, Lacy A; Jennings, John D; Lang, James A; Kenney, W Larry

    2010-06-01

    Chronic systemic platelet cyclooxygenase (COX) inhibition with low-dose aspirin [acetylsalicylic acid (ASA)] significantly attenuates reflex cutaneous vasodilation in middle-aged humans, whereas acute, localized, nonisoform-specific inhibition of vascular COX with intradermal administration of ketorolac does not alter skin blood flow during hyperthermia. Taken together, these data suggest that platelets may be involved in reflex cutaneous vasodilation, and this response is inhibited with systemic pharmacological platelet inhibition. We hypothesized that, similar to ASA, specific platelet ADP receptor inhibition with clopidogrel would attenuate reflex vasodilation in middle-aged skin. In a double-blind crossover design, 10 subjects (53+/-2 yr) were instrumented with four microdialysis fibers for localized drug administration and heated to increase body core temperature [oral temperature (Tor)] 1 degrees C during no systemic drug (ND), and after 7 days of systemic ASA (81 mg) and clopidogrel (75 mg) treatment. Skin blood flow (SkBF) was measured using laser-Doppler flowmetry over each site assigned as 1) control, 2) nitric oxide synthase inhibited (NOS-I; 10 mM NG-nitro-L-arginine methyl ester), 3) COX inhibited (COX-I; 10 mM ketorolac), and 4) NOS-I+COX-I. Data were normalized and presented as a percentage of maximal cutaneous vascular conductance (%CVCmax; 28 mM sodium nitroprusside+local heating to 43 degrees C). During ND conditions, SkBF with change (Delta) in Tor=1.0 degrees C was 56+/-3% CVCmax. Systemic low-dose ASA and clopidogrel both attenuated reflex vasodilation (ASA: 43+/-3; clopidogrel: 32+/-3% CVCmax; both P0.05). NOS-I attenuated vasodilation in ND and ASA (ND: 28+/-6; ASA: 25+/-4% CVCmax; both P0.05). NOS-I+COX-I was not different compared with NOS-I alone in either systemic treatment condition. Both systemic ASA and clopidogrel reduced the time required to increase Tor 1 degrees C (ND: 58+/-3 vs. ASA: 45+/-2; clopidogrel: 39+/-2 min; both Preflex

  18. Sodium fusidate ameliorates the course of diabetes induced in mice by multiple low doses of streptozotocin

    DEFF Research Database (Denmark)

    Nicoletti, F; Di Marco, R; Conget, I

    2000-01-01

    We studied the effects of the immunosuppressant sodium fusidate (fusidin) on murine immunoinflammatory diabetes mellitus (DM) induced by multiple low doses of streptozotocin (SZ). Fusidin was given by gavage to three strains of mice (C57KsJ, C57BL/6, CD1) at doses 10 or 100 mg/kg body weight every...... induced in vivo by ConA, reducing the levels of IFN-gamma, IL-2 and TNF-alpha and augmenting the level of IL-6. However, only the inhibitory effect of the drug on the synthesis/release of IFN-gamma seemed to be causally related to its capacity to counteract the SZ-induced DM. In fact, the disease...... other day. The drug was administered as an early or late prophylactic regime starting either 1 day prior to the first or after the fifth and last injection of SZ. In both situations the largest dose of fusidin successfully reduced the clinical, chemical and histological signs of DM, the treated mice...

  19. Low dose of L-glutamic acid attenuated the neurological dysfunctions and excitotoxicity in bilateral common carotid artery occluded mice.

    Science.gov (United States)

    Ramanathan, Muthiah; Abdul, Khadar K; Justin, Antony

    2016-10-01

    Glutamate, an excitatory neurotransmitter in the brain, produces excitotoxicity through its agonistic action on postsynaptic N-methyl-D-aspartate receptor, resulting in neurodegeneration. We hypothesized that the administration of low doses of glutamate in cerebral ischemia could attenuate the excitotoxicity in neurons through its autoreceptor regulatory mechanism, and thereby control neurodegeneration. To test the hypothesis, the effect of L-glutamic acid (L-GA) 400 μmol/l/kg was evaluated in a bilateral common carotid artery occlusion-induced global ischemic mouse model. Memantine was used as a positive control. Global ischemia in mice was induced by occlusion of both the common carotid artery (bilateral common carotid artery occlusion) for 20 min, followed by reperfusion injury. L-GA was infused slowly through the tail vein 30 min before the surgery and every 24 h thereafter until the end of the experiment. The time-dependent change in cerebral blood flow was monitored using a laser Doppler image analyzer. The neurotransmitters glutamate and γ-aminobutyric acid (GABA) and the neurobiochemicals ATP, glutathione, and nitric oxide were measured in the different regions of brain at 0, 24, 48, and 72 h after reperfusion injury. L-GA increased locomotor activity, muscle coordination, and cerebral blood flow in ischemic mice at 72 h after ischemic insult. L-GA reduced glutamate levels in the cortex, striatum, and hippocampus at 72 h, whereas GABA levels were elevated in all three brain regions studied. Further, L-GA elevated glutathione levels and attenuated nitric oxide levels, but failed to restore ATP levels 72 h after ischemia-reperfusion. We conclude that the gradual reduction of glutamate along with elevation of GABA in different brain regions could have contributed toward the neuroprotective effect of L-GA. Hence, a slow infusion of a low dose of L-GA could be beneficial in controlling excitotoxicity-induced neurodegeneration following ischemia.

  20. 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.

  1. 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

  2. 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.

  3. Immune cell-derived c3 is required for autoimmune diabetes induced by multiple low doses of streptozotocin.

    Science.gov (United States)

    Lin, Marvin; Yin, Na; Murphy, Barbara; Medof, M Edward; Segerer, Stephan; Heeger, Peter S; Schröppel, Bernd

    2010-09-01

    The complement system contributes to autoimmune injury, but its involvement in promoting the development of autoimmune diabetes is unknown. In this study, our goal was to ascertain the role of complement C3 in autoimmune diabetes. Susceptibility to diabetes development after multiple low-dose streptozotocin treatment in wild-type (WT) and C3-deficient mice was analyzed. Bone marrow chimeras, luminex, and quantitative reverse transcription PCR assays were performed to evaluate the phenotypic and immunologic impact of C3 in the development of this diabetes model. Coincident with the induced elevations in blood glucose levels, we documented alternative pathway complement component gene expression within the islets of the diabetic WT mice. When we repeated the experiments with C3-deficient mice, we observed complete resistance to disease, as assessed by the absence of histologic insulitis and the absence of T-cell reactivity to islet antigens. Studies of WT chimeras bearing C3-deficient bone marrow cells showed that bone marrow cell-derived C3, and not serum C3, is involved in the induction of diabetes in this model. The data reveal a key role for immune cell-derived C3 in the pathogenesis of murine multiple low-dose streptozotocin-induced diabetes and support the concept that immune cell mediated diabetes is in part complement-dependent.

  4. Motion-compensated PET image reconstruction with respiratory-matched attenuation correction using two low-dose inhale and exhale CT images

    International Nuclear Information System (INIS)

    Nam, Woo Hyun; Ahn, Il Jun; Ra, Jong Beom; Kim, Kyeong Min; Kim, Byung Il

    2013-01-01

    Positron emission tomography (PET) is widely used for diagnosis and follow up assessment of radiotherapy. However, thoracic and abdominal PET suffers from false staging and incorrect quantification of the radioactive uptake of lesion(s) due to respiratory motion. Furthermore, respiratory motion-induced mismatch between a computed tomography (CT) attenuation map and PET data often leads to significant artifacts in the reconstructed PET image. To solve these problems, we propose a unified framework for respiratory-matched attenuation correction and motion compensation of respiratory-gated PET. For the attenuation correction, the proposed algorithm manipulates a 4D CT image virtually generated from two low-dose inhale and exhale CT images, rather than a real 4D CT image which significantly increases the radiation burden on a patient. It also utilizes CT-driven motion fields for motion compensation. To realize the proposed algorithm, we propose an improved region-based approach for non-rigid registration between body CT images, and we suggest a selection scheme of 3D CT images that are respiratory-matched to each respiratory-gated sinogram. In this work, the proposed algorithm was evaluated qualitatively and quantitatively by using patient datasets including lung and/or liver lesion(s). Experimental results show that the method can provide much clearer organ boundaries and more accurate lesion information than existing algorithms by utilizing two low-dose CT images. (paper)

  5. Characterization of a Mouse Model of Emphysema Induced by Multiple Instillations of Low-Dose Elastase

    Directory of Open Access Journals (Sweden)

    Milena V. Oliveira

    2016-10-01

    Full Text Available Many experimental models have been proposed to study the pathophysiological features of emphysema, as well as to search for new therapeutic approaches for acute or chronically injured lung parenchyma. We aimed to characterize an emphysema model induced by multiple instillations of elastase by tracking the changes in inflammation, remodeling, and cardiac function after each instillation. Forty-eight C57BL/6 mice were randomly assigned across 2 groups. Emphysema (ELA animals received 1, 2, 3, or 4 intratracheal instillations of pancreatic porcine elastase (PPE, 0.2 IU with a 1-week interval between them. Controls (C received saline following the same protocol. Before and after implementation of the protocol, animals underwent echocardiographic analysis. After the first instillation of PPE, the percentage of mononuclear cells in the lung parenchyma was increased compared to C (p = 0.0001. The second instillation resulted in hyperinflated alveoli, increased mean linear intercept, and reduced elastic fiber content in lung parenchyma compared to C (p=0.0197. Following the third instillation, neutrophils and collagen fiber content in alveolar septa and airways were increased, whereas static lung elastance was reduced compared to C (p=0.0094. After the fourth instillation, the percentage of M1 macrophages in lungs; levels of interleukin-1beta, keratinocyte-derived chemokine, hepatocyte growth factor, and vascular endothelial growth factor; and collagen fiber content in the pulmonary vessel wall were increased compared to C (p=0.0096. At this time point, pulmonary arterial hypertension was apparent, with increased diastolic right ventricular wall thickness. In conclusion, the initial phase of emphysema was characterized by lung inflammation with predominance of mononuclear cells, whereas at the late stage, impairment of pulmonary and cardiovascular functions was observed. This model enables analysis of therapies at different time points during controlled

  6. Low Dose Vaccination with Attenuated Francisella tularensis Strain SchuS4 Mutants Protects against Tularemia Independent of the Route of Vaccination

    Science.gov (United States)

    Rockx-Brouwer, Dedeke; Chong, Audrey; Wehrly, Tara D.; Child, Robert; Crane, Deborah D.

    2012-01-01

    Tularemia, caused by the Gram-negative bacterium Francisella tularensis, is a severe, sometimes fatal disease. Interest in tularemia has increased over the last decade due to its history as a biological weapon. In particular, development of novel vaccines directed at protecting against pneumonic tularemia has been an important goal. Previous work has demonstrated that, when delivered at very high inoculums, administration of live, highly attenuated strains of virulent F. tularensis can protect against tularemia. However, lower vaccinating inoculums did not offer similar immunity. One concern of using live vaccines is that the host may develop mild tularemia in response to infection and use of high inoculums may contribute to this issue. Thus, generation of a live vaccine that can efficiently protect against tularemia when delivered in low numbers, e.g. tularemia when delivered at concentrations of approximately 50 or fewer bacteria. Attenuated strains for use as vaccines were selected by their inability to efficiently replicate in macrophages in vitro and impaired replication and dissemination in vivo. Although all strains were defective for replication in vitro within macrophages, protective efficacy of each attenuated mutant was correlated with their ability to modestly replicate and disseminate in the host. Finally, we demonstrate the parenteral vaccination with these strains offered superior protection against pneumonic tularemia than intranasal vaccination. Together our data provides proof of principle that low dose attenuated vaccines may be a viable goal in development of novel vaccines directed against tularemia. PMID:22662210

  7. Bisphenol A (BPA) aggravates multiple low-dose streptozotocin-induced Type 1 diabetes in C57BL/6 mice.

    Science.gov (United States)

    Cetkovic-Cvrlje, Marina; Thinamany, Sinduja; Bruner, Kylie A

    2017-12-01

    Type 1 diabetes (T1D) is a T-cell-mediated autoimmune disorder characterized by destruction of insulin-producing pancreatic β-cells. Whereas epidemiological data implicate environmental factors in the increasing incidence of T1D, their identity remains unknown. Though exposure to bisphenol A (BPA) has been associated with several disorders, no epidemiologic evidence has linked BPA exposure and T1D. The goal of this study was to elucidate diabetogenic potentials of BPA and underlying mechanisms in the context of T-cell immunity, in a multiple low-dose streptozotocin (MLDSTZ)-induced autoimmune mouse T1D model. C57BL/6 mice were orally exposed to 1 or 10 mg BPA/L starting at 4 wk of age; diabetes was induced at 9 wk of age with STZ. T-cell composition, function, and insulitis levels were studied at Days 11 and 50 during diabetes development (i.e. post-first STZ injection). Results showed both BPA doses increased diabetes incidence and affected T-cell immunity. However, mechanisms of diabetogenic action appeared divergent based on dose. Low-dose BPA fits a profile of an agent that exhibits pro-diabetogenic effects via T-cell immunomodulation in the early stages of disease development, i.e. decreases in splenic T-cell subpopulations [especially CD4 + T-cells] along with a trend in elevation of splenic T-cell formation of pro-inflammatory cytokines (IFN-γ, TNF-α, and IL-6). In contrast, high-dose BPA did not affect T-cell populations and led to decreased levels of IFN-γ and TNF-α. Both treatments did not affect insulitis levels at the disease early stage, but aggravated it later on. By the study end, besides decreasing T-cell proliferative capacity, low-dose BPA did not affect other T-cell-related parameters, including cytokine secretion, comparable to the effects of high-dose BPA. In conclusion, this study confirmed BPA as a potential diabetogenic compound with immunomodulatory mechanisms of action - in the context of T-cell immunity - that seemed to be dose

  8. Effects of multiple low dose radiation on spleen T lymphocyte subgroups in eight-week diabetic rats

    International Nuclear Information System (INIS)

    Guan Feng; Li Yanbo; Zhao Hongguang; Guo Wei; Wang Zhicheng; Gong Shouliang; Guo Caixia

    2008-01-01

    Objective: To explore the changes of spleen lymphocyte subgroups in diabetic rats after multiple low dose radiation (LDR). Methods: The experiment was divided into normal control group, pure diabetes mellitus (DM) group, and DM plus different doses of irradiation groups (the irradiation doses were 0.025, 0.050 and 0.075 Gy, respectively). The diabetic rat model was induced by intraperitoneal injection of streptozotocin. After the diabetic rats were irradiated 15 times, the percentages of spleen CD4 + and CD8 + T cells and ratio of CD4 + /CD8 + T cells were detected with flow cytometry on the fourth weekend. Results: The diabetic rats manifested obvious polydipsia, polyphagia, polyuria and weight loss. On the fourth weekend after irradiation, as compared with normal control group, the percentage of spleen CD4 + T cells increased significantly (P + T cells decreased significantly (P + /CD8 + T cells was increased significantly (P + T cells were declined markedly in both 0.050 and 0.075 Gy plus DM groups (P + T cells increased significantly in LDR plus DM groups (P + /CD8 + T cells was declined obviously (P<0.01). Conclusion: The multiple LDR could regulate the immune function in diabetic rats, and rectificate the immunological imbalance in order to protect body. (authors)

  9. Low dose vaccination with attenuated Francisella tularensis strain SchuS4 mutants protects against tularemia independent of the route of vaccination.

    Directory of Open Access Journals (Sweden)

    Dedeke Rockx-Brouwer

    Full Text Available Tularemia, caused by the gram-negative bacterium Francisella tularensis, is a severe, sometimes fatal disease. Interest in tularemia has increased over the last decade due to its history as a biological weapon. In particular, development of novel vaccines directed at protecting against pneumonic tularemia has been an important goal. Previous work has demonstrated that, when delivered at very high inoculums, administration of live, highly attenuated strains of virulent F. tularensis can protect against tularemia. However, lower vaccinating inoculums did not offer similar immunity. One concern of using live vaccines is that the host may develop mild tularemia in response to infection and use of high inoculums may contribute to this issue. Thus, generation of a live vaccine that can efficiently protect against tularemia when delivered in low numbers, e.g. <100 organisms, may address this concern. Herein we describe the ability of three defined, attenuated mutants of F. tularensis SchuS4, deleted for FTT0369c, FTT1676, or FTT0369c and FTT1676, respectively, to engender protective immunity against tularemia when delivered at concentrations of approximately 50 or fewer bacteria. Attenuated strains for use as vaccines were selected by their inability to efficiently replicate in macrophages in vitro and impaired replication and dissemination in vivo. Although all strains were defective for replication in vitro within macrophages, protective efficacy of each attenuated mutant was correlated with their ability to modestly replicate and disseminate in the host. Finally, we demonstrate the parenteral vaccination with these strains offered superior protection against pneumonic tularemia than intranasal vaccination. Together our data provides proof of principle that low dose attenuated vaccines may be a viable goal in development of novel vaccines directed against tularemia.

  10. Emphysema quantification on low-dose CT using percentage of low-attenuation volume and size distribution of low-attenuation lung regions: Effects of adaptive iterative dose reduction using 3D processing

    Energy Technology Data Exchange (ETDEWEB)

    Nishio, Mizuho, E-mail: nmizuho@med.kobe-u.ac.jp [Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Matsumoto, Sumiaki, E-mail: sumatsu@med.kobe-u.ac.jp [Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Seki, Shinichiro, E-mail: sshin@med.kobe-u.ac.jp [Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Koyama, Hisanobu, E-mail: hkoyama@med.kobe-u.ac.jp [Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Ohno, Yoshiharu, E-mail: yosirad@kobe-u.ac.jp [Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Fujisawa, Yasuko, E-mail: yasuko1.fujisawa@toshiba.co.jp [Toshiba Medical Systems Corporation, 1385 Shimoishigami, Otawara, Tochigi 324-8550 (Japan); Sugihara, Naoki, E-mail: naoki.sugihara@toshiba.co.jp [Toshiba Medical Systems Corporation, 1385 Shimoishigami, Otawara, Tochigi 324-8550 (Japan); and others

    2014-12-15

    Highlights: • Emphysema quantification (LAV% and D) was affected by image noise on low-dose CT. • For LAV% and D, AIDR 3D improved agreement of quantification on low-dose CT. • AIDR 3D has the potential to quantify emphysema accurately on low-dose CT. - Abstract: Purpose: To evaluate the effects of adaptive iterative dose reduction using 3D processing (AIDR 3D) for quantification of two measures of emphysema: percentage of low-attenuation volume (LAV%) and size distribution of low-attenuation lung regions. Method and materials: : Fifty-two patients who underwent standard-dose (SDCT) and low-dose CT (LDCT) were included. SDCT without AIDR 3D, LDCT without AIDR 3D, and LDCT with AIDR 3D were used for emphysema quantification. First, LAV% was computed at 10 thresholds from −990 to −900 HU. Next, at the same thresholds, linear regression on a log–log plot was used to compute the power law exponent (D) for the cumulative frequency-size distribution of low-attenuation lung regions. Bland–Altman analysis was used to assess whether AIDR 3D improved agreement between LDCT and SDCT for emphysema quantification of LAV% and D. Results: The mean relative differences in LAV% between LDCT without AIDR 3D and SDCT were 3.73%–88.18% and between LDCT with AIDR 3D and SDCT were −6.61% to 0.406%. The mean relative differences in D between LDCT without AIDR 3D and SDCT were 8.22%–19.11% and between LDCT with AIDR 3D and SDCT were 1.82%–4.79%. AIDR 3D improved agreement between LDCT and SDCT at thresholds from −930 to −990 HU for LAV% and at all thresholds for D. Conclusion: AIDR 3D improved the consistency between LDCT and SDCT for emphysema quantification of LAV% and D.

  11. Effects of multiple low dose radiation on the apoptosis of splenocytes and immune factor in male diabetic rats

    International Nuclear Information System (INIS)

    Li Yanbo; Guo Caixia; Dong Lihua; Wang Jianfeng; Liu Shuchun; Lu Zhe; Gong Shouliang

    2009-01-01

    Objective: To explore the effect of multiple low dose radiation (LDR) on the apoptosis of splenocytes and immune factors in diabetes mellitus (DM) rats. Methods: The rats were randomly divided into control, DM and DM + LDR groups. The irradiation doses were 25, 50 and 75 mGy, and the irradiated times were 15. At the fourth weekend after the DM rats irradiated, the apoptotic rate and TCRαβ percentage of splenocytes were detected by flow cytometry, and the content of IL-2 in both serum and supernatant of cultured splenocytes were detected by ELISA. Results: Compared with that in the control, the body weight (BW) decreased in the DM and DM + LDR groups,particularly in DM group. The blood glucose (BG) level in the DM + LDR groups was higher than that in the control, but decreased significantly as compared with that in the DM group (P < 0.01). As compared with those in the control, the apoptotic rate in DM + 50 mGy (P < 0.05) and the content of serum IL-2 in DM + 75 mGy group (P < 0.01) all increased significantly, while the content of IL-2 in supernatant of cultured splenocytes decreased significantly in the DM + LDR groups. Compared with those in the DM group, the apoptotic rate and the percentage of TCRαβ in splenocytes in the DM + LDR groups (P < 0.01-P < 0.001) and the content of IL-2 in serum in DM + 50 mGy group (P < 0.01) decreased significantly. Conclusions: The multiple LDR could weaken the loss of BW and increase of BG caused by DM, decrease the splenocyte apoptosis induced by DM, and regulate the immune factors. (authors)

  12. 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.

  13. GLUT2 in pancreatic islets: crucial target molecule in diabetes induced with multiple low doses of streptozotocin in mice.

    Science.gov (United States)

    Wang, Z; Gleichmann, H

    1998-01-01

    In mice, diabetes can be induced by multiple low doses of streptozotocin (MLD-STZ), i.e., 40 mg/kg body wt on each of 5 consecutive days. In this model, diabetes develops only when STZ induces both beta-cell toxicity and T-cell-dependent immune reactions. The target molecule(s) of MLD-STZ-induced beta-cell toxicity are not known, however. In this study, we report that GLUT2 is a target molecule for MLD-STZ toxicity. Ex vivo, a gradual decrement of both GLUT2 protein and mRNA expression was found in pancreatic islets isolated from MLD-STZ-treated C57BL/6 male mice, whereas mRNA expression of beta-actin, glucokinase, and proinsulin remained unaffected. Significant reduction of both GLUT2 protein and mRNA expression was first noted 1 day after the third STZ injection, clearly preceding the onset of hyperglycemia. The extent of reduction increased with the number of STZ injections administered and increased over time, after the last, i.e., fifth, STZ injection. The STZ-induced reduction of GLUT2 protein and mRNA was not due to an essential loss of beta-cells, because ex vivo, not only the total RNA yield and protein content in isolated islets, but also proinsulin mRNA expression, failed to differ significantly in the differently treated groups. Furthermore, islets isolated from MLD-STZ-treated donors responded to the nonglucose secretagogue arginine in a pattern similar to that of solvent-treated donors. Interestingly, the MLD-STZ-induced reduction of both GLUT2 protein and mRNA was prevented by preinjecting mice with 5-thio-D-glucose before each STZ injection. Apparently, GLUT2 is a crucial target molecule of MLD-STZ toxicity, and this toxicity seems to precede the immune reactions against beta-cells.

  14. Analysis of renal impairment in MM-003, a phase III study of pomalidomide + low - dose dexamethasone versus high - dose dexamethasone in refractory or relapsed and refractory multiple myeloma

    Science.gov (United States)

    Weisel, Katja C.; Dimopoulos, Meletios A.; Moreau, Philippe; Lacy, Martha Q.; Song, Kevin W.; Delforge, Michel; Karlin, Lionel; Goldschmidt, Hartmut; Banos, Anne; Oriol, Albert; Alegre, Adrian; Chen, Christine; Cavo, Michele; Garderet, Laurent; Ivanova, Valentina; Martinez-Lopez, Joaquin; Knop, Stefan; Yu, Xin; Hong, Kevin; Sternas, Lars; Jacques, Christian; Zaki, Mohamed H.; Miguel, Jesus San

    2016-01-01

    Pomalidomide + low-dose dexamethasone is effective and well tolerated for refractory or relapsed and refractory multiple myeloma after bortezomib and lenalidomide failure. The phase III trial MM-003 compared pomalidomide + low-dose dexamethasone with high-dose dexamethasone. This subanalysis grouped patients by baseline creatinine clearance ≥ 30 − < 60 mL/min (n=93, pomalidomide + low-dose dexamethasone; n=56, high-dose dexamethasone) or ≥ 60 mL/min (n=205, pomalidomide + low-dose dexamethasone; n=93, high-dose dexamethasone). Median progression-free survival was similar for both subgroups and favored pomalidomide + low-dose dexamethasone versus high-dose dexamethasone: 4.0 versus 1.9 months in the group with baseline creatinine clearance ≥ 30 − < 60 mL/min (P<0.001) and 4.0 versus 2.0 months in the group with baseline creatinine clearance ≥ 60 mL/min (P<0.001). Median overall survival for pomalidomide + low-dose dexamethasone versus high-dose dexamethasone was 10.4 versus 4.9 months (P=0.030) and 15.5 versus 9.2 months (P=0.133), respectively. Improved renal function, defined as an increase in creatinine clearance from < 60 to ≥ 60 mL/min, was similar in pomalidomide + low-dose dexamethasone and high-dose dexamethasone patients (42% and 47%, respectively). Improvement in progression-free and overall survival in these patients was comparable with that in patients without renal impairment. There was no increase in discontinuations of therapy, dose modifications, and adverse events in patients with moderate renal impairment. Pomalidomide at a starting dose of 4 mg + low-dose dexamethasone is well tolerated in patients with refractory or relapsed and refractory multiple myeloma, and of comparable efficacy if moderate renal impairment is present. This trial was registered with clinicaltrials.gov identifier 01311687 and EudraCT identifier 2010-019820-30. PMID:27081177

  15. SU-E-I-86: Ultra-Low Dose Computed Tomography Attenuation Correction for Pediatric PET CT Using Adaptive Statistical Iterative Reconstruction (ASiR™)

    Energy Technology Data Exchange (ETDEWEB)

    Brady, S; Shulkin, B [St. Jude Children’s Research Hospital, Memphis, TN (United States)

    2015-06-15

    Purpose: To develop ultra-low dose computed tomography (CT) attenuation correction (CTAC) acquisition protocols for pediatric positron emission tomography CT (PET CT). Methods: A GE Discovery 690 PET CT hybrid scanner was used to investigate the change to quantitative PET and CT measurements when operated at ultra-low doses (10–35 mAs). CT quantitation: noise, low-contrast resolution, and CT numbers for eleven tissue substitutes were analyzed in-phantom. CT quantitation was analyzed to a reduction of 90% CTDIvol (0.39/3.64; mGy) radiation dose from baseline. To minimize noise infiltration, 100% adaptive statistical iterative reconstruction (ASiR) was used for CT reconstruction. PET images were reconstructed with the lower-dose CTAC iterations and analyzed for: maximum body weight standardized uptake value (SUVbw) of various diameter targets (range 8–37 mm), background uniformity, and spatial resolution. Radiation organ dose, as derived from patient exam size specific dose estimate (SSDE), was converted to effective dose using the standard ICRP report 103 method. Effective dose and CTAC noise magnitude were compared for 140 patient examinations (76 post-ASiR implementation) to determine relative patient population dose reduction and noise control. Results: CT numbers were constant to within 10% from the non-dose reduced CTAC image down to 90% dose reduction. No change in SUVbw, background percent uniformity, or spatial resolution for PET images reconstructed with CTAC protocols reconstructed with ASiR and down to 90% dose reduction. Patient population effective dose analysis demonstrated relative CTAC dose reductions between 62%–86% (3.2/8.3−0.9/6.2; mSv). Noise magnitude in dose-reduced patient images increased but was not statistically different from pre dose-reduced patient images. Conclusion: Using ASiR allowed for aggressive reduction in CTAC dose with no change in PET reconstructed images while maintaining sufficient image quality for co

  16. Responses of rat R-1 cells to low dose rate gamma radiation and multiple daily dose fractions

    International Nuclear Information System (INIS)

    Kal, H.B.; Bijman, J.Th.

    1981-01-01

    Multifraction irradiation may offer the same therapeutic gain as continuous irradiation. Therefore, a comparison of the efficacy of low dose rate irradiation and multifraction irradiation was the main objective of the experiments to be described. Both regimens were tested on rat rhabdomyosarcoma (R-1) cells in vitro and in vivo. Exponentially growing R-1 cells were treated in vitro by a multifraction irradiation procedure with dose fractions of 2 Gy gamma radiation and time intervals of 1 to 3 h. The dose rate was 1.3 Gy.min -1 . The results indicate that multifractionation of the total dose is more effective with respect to cell inactivation than continuous irradiation. (Auth.)

  17. Adverse event management in patients with relapsed and refractory multiple myeloma taking pomalidomide plus low-dose dexamethasone: A pooled analysis.

    Science.gov (United States)

    Moreau, Philippe; Dimopoulos, Meletios A; Richardson, Paul G; Siegel, David S; Cavo, Michele; Corradini, Paolo; Weisel, Katja; Delforge, Michel; O'Gorman, Peter; Song, Kevin; Chen, Christine; Bahlis, Nizar; Oriol, Albert; Hansson, Markus; Kaiser, Martin; Anttila, Pekka; Raymakers, Reinier; Joao, Cristina; Cook, Gordon; Sternas, Lars; Biyukov, Tsvetan; Slaughter, Ana; Hong, Kevin; Herring, Jennifer; Yu, Xin; Zaki, Mohamed; San-Miguel, Jesus

    2017-09-01

    Heavily pretreated patients with relapsed and refractory multiple myeloma are susceptible to treatment-related adverse events (AEs). Managing AEs are important to ensure patients continue therapy long enough to receive the best clinical benefit. Data from the MM-002, MM-003, and MM-010 trials were pooled to further characterize the safety profile of pomalidomide plus low-dose dexamethasone and AE management. This analysis included 1088 patients who received ≥ 2 prior therapies, including lenalidomide and bortezomib, and progressed ≤ 60 days of last therapy. Patients received 28-day cycles of pomalidomide 4 mg/day on days 1-21 and low-dose dexamethasone 40 mg (20 mg if aged > 75 years) weekly until disease progression or unacceptable toxicity. Thromboprophylaxis was required. The most common grade 3/4 AEs were neutropenia (56.2%), anemia (32.3%), and thrombocytopenia (25.8%), which occurred within the first few cycles of treatment. Grade 3/4 infections occurred in 33.7% patients, of whom 13.9% had pneumonia, and 40.3% had neutropenia. Pomalidomide dose reductions or interruptions were reported in 24.2% and 66.0% of patients, respectively. AEs were managed by dose modifications and/or supportive care. Pomalidomide plus low-dose dexamethasone showed an acceptable safety profile, and AEs were well managed according to study protocols and established guidelines. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. Attenuation of multiples in image space

    Science.gov (United States)

    Alvarez, Gabriel F.

    In complex subsurface areas, attenuation of 3D specular and diffracted multiples in data space is difficult and inaccurate. In those areas, image space is an attractive alternative. There are several reasons: (1) migration increases the signal-to-noise ratio of the data; (2) primaries are mapped to coherent events in Subsurface Offset Domain Common Image Gathers (SODCIGs) or Angle Domain Common Image Gathers (ADCIGs); (3) image space is regular and smaller; (4) attenuating the multiples in data space leaves holes in the frequency-Wavenumber space that generate artifacts after migration. I develop a new equation for the residual moveout of specular multiples in ADCIGs and use it for the kernel of an apex-shifted Radon transform to focus and separate the primaries from specular and diffracted multiples. Because of small amplitude, phase and kinematic errors in the multiple estimate, we need adaptive matching and subtraction to estimate the primaries. I pose this problem as an iterative least-squares inversion that simultaneously matches the estimates of primaries and multiples to the data. Standard methods match only the estimate of the multiples. I demonstrate with real and synthetic data that the method produces primaries and multiples with little cross-talk. In 3D, the multiples exhibit residual moveout in SODCIGs in in-line and cross-line offsets. They map away from zero subsurface offsets when migrated with the faster velocity of the primaries. In ADCIGs the residual moveout of the primaries as a function of the aperture angle, for a given azimuth, is flat for those angles that illuminate the reflector. The multiples have residual moveout towards increasing depth for increasing aperture angles at all azimuths. As a function of azimuth, the primaries have better azimuth resolution than the multiples at larger aperture angles. I show, with a real 3D dataset, that even below salt, where illumination is poor, the multiples are well attenuated in ADCIGs with the new

  19. ß-cell specific overexpression of suppressor of cytokine signalling-3 does not protect against multiple low dose streptozotocin induced type 1 diabetes in mice

    DEFF Research Database (Denmark)

    Börjesson, A; Rønn, S G; Karlsen, A E

    2011-01-01

    We investigated the impact of ß-cell specific overexpression of suppressor of cytokine signalling-3 (SOCS-3) on the development of multiple low dose streptozotocin (MLDSTZ) induced Type 1 diabetes and the possible mechanisms involved. MLDSTZ treatment was administered to RIP-SOCS-3 transgenic......RNA in islet cells and secretion of IL-1Ra into culture medium. MLDSTZ treatment caused gradual hyperglycemia both in the wt mice and in the transgenic mice with the latter tending to be more sensitive. In vitro experiments on wt and transgenic islets did not reveal any differences in sensitivity to damaging...

  20. 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.)

  1. 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)

  2. Clinical and prognostic significance of bone marrow abnormalities in the appendicular skeleton detected by low-dose whole-body multidetector computed tomography in patients with multiple myeloma

    International Nuclear Information System (INIS)

    Nishida, Y; Matsue, Y; Suehara, Y; Fukumoto, K; Fujisawa, M; Takeuchi, M; Ouchi, E; Matsue, K

    2015-01-01

    Clinical significance of medullary abnormalities in the appendicular skeleton (AS) detected by low-dose whole-body multidetector computed tomography (MDCT) in patients with multiple myeloma (MM) was investigated. A total of 172 patients with monoclonal gammopathy of undetermined significance (MGUS) (n=17), smoldering MM (n=47) and symptomatic MM (n=108) underwent low-dose MDCT. CT values (CTv) of medullary density of AS⩾0 Hounsfield unit (HU) was considered as abnormal. Percentage of medullary abnormalities and the mean CTv of AS in patients with MGUS, smoldering MM and symptomatic MM were 18, 55 and 62% and −44.5 , −20.3 and 11.2 HU, respectively (P<0.001 and P<0.001). Disease progression of MM was independently associated with high CTv on multivariate analysis. In symptomatic MM, the presence of abnormal medullary lesions was associated with increased incidence of high-risk cytogenetic abnormalities (34.4% vs 7.7% P=0.002) and extramedullary disease (10.4% vs 0% P=0.032). It was also an independent poor prognostic predictor (hazard ratio 3.546, P=0.04). This study showed that CTv of AS by MDCT is correlated with disease progression of MM, and the presence of abnormal medullary lesions is a predictor for poor survival

  3. Comparative Efficacy of Daratumumab Monotherapy and Pomalidomide Plus Low-Dose Dexamethasone in the Treatment of Multiple Myeloma: A Matching Adjusted Indirect Comparison.

    Science.gov (United States)

    Van Sanden, Suzy; Ito, Tetsuro; Diels, Joris; Vogel, Martin; Belch, Andrew; Oriol, Albert

    2018-03-01

    Daratumumab (a human CD38-directed monoclonal antibody) and pomalidomide (an immunomodulatory drug) plus dexamethasone are both relatively new treatment options for patients with heavily pretreated multiple myeloma. A matching adjusted indirect comparison (MAIC) was used to compare absolute treatment effects of daratumumab versus pomalidomide + low-dose dexamethasone (LoDex; 40 mg) on overall survival (OS), while adjusting for differences between the trial populations. The MAIC method reduces the risk of bias associated with naïve indirect comparisons. Data from 148 patients receiving daratumumab (16 mg/kg), pooled from the GEN501 and SIRIUS studies, were compared separately with data from patients receiving pomalidomide + LoDex in the MM-003 and STRATUS studies. The MAIC-adjusted hazard ratio (HR) for OS of daratumumab versus pomalidomide + LoDex was 0.56 (95% confidence interval [CI], 0.38-0.83; p  = .0041) for MM-003 and 0.51 (95% CI, 0.37-0.69; p  < .0001) for STRATUS. The treatment benefit was even more pronounced when the daratumumab population was restricted to pomalidomide-naïve patients (MM-003: HR, 0.33; 95% CI, 0.17-0.66; p  = .0017; STRATUS: HR, 0.41; 95% CI, 0.21-0.79; p  = .0082). An additional analysis indicated a consistent trend of the OS benefit across subgroups based on M-protein level reduction (≥50%, ≥25%, and <25%). The MAIC results suggest that daratumumab improves OS compared with pomalidomide + LoDex in patients with heavily pretreated multiple myeloma. This matching adjusted indirect comparison of clinical trial data from four studies analyzes the survival outcomes of patients with heavily pretreated, relapsed/refractory multiple myeloma who received either daratumumab monotherapy or pomalidomide plus low-dose dexamethasone. Using this method, daratumumab conferred a significant overall survival benefit compared with pomalidomide plus low-dose dexamethasone. In the absence of head-to-head trials, these

  4. Suppressor of cytokine signaling 2 (SOCS2) deletion protects against multiple low dose streptozotocin-induced type 1 diabetes in adult male mice

    DEFF Research Database (Denmark)

    Alkharusi, Amira; Mirecki-Garrido, Mercedes; Ma, Zuheng

    2016-01-01

    Background: Diabetes type 1 is characterized by the failure of beta cells to produce insulin. Suppressor of cytokine signaling (SOCS) proteins are important regulators of the Janus kinase/signal transducer and activator of transcription (JAK-STAT) pathway. Previous studies have shown that GH can...... prevent the development of type I diabetes in mice and that SOCS2 deficiency mimics a state of increased GH sensitivity. Methodology: The elevated sensitivity of SOCS2-/- mice to GH and possibly to PRL was the rationale to analyze the effects of multiple low dose streptozotocin (MLDSTZ)-induced diabetes...... in SOCS2-/- mice. Results: We show that 6-month-old SOCS2-/- mice, but not 2-month-old mice, were less sensitive to MLDSTZ-induced diabetes, compared to controls. MLDSTZ treatment induced glucose intolerance in both SOCS2+/+ and SOCS2-/- mice, as shown by glucose tolerance tests, with SOCS2+/+ mice...

  5. Evaluation of multiple low doses of copper oxide wire particles compared with levamisole for control of Haemonchus contortus in lambs.

    Science.gov (United States)

    Burke, J M; Miller, J E

    2006-06-30

    High levels of anthelmintic resistance in gastrointestinal nematodes (GIN) of small ruminants have created the need for alternative approaches to parasite control. Copper oxide wire particles (COWP; 2g) have proven effective in decreasing GIN infection in lambs. However, the risk of copper toxicity has limited the usefulness of this approach. Recently, smaller doses (0.5 and 1g) have proven effective in GIN control, reducing the risk of toxicity. The objective of this study was to examine the effectiveness and risk of toxicity using multiple small doses of COWP for GIN control in lambs between weaning and market weight. Dorper crossbred ram lambs were orally administered levamisole (Levasol, 8.0mg/kg; n=8), 0.5g (n=9), or 1g COWP (n=9) at weaning (Day 0; 118+/-2 days of age; late May 2005) and again at 6-week intervals for a total of four treatments. A pooled fecal culture determined that Haemonchus contortus was the predominant gastrointestinal parasite at weaning. Lambs grazed bermudagrass pastures and were supplemented with up to 500g corn/soybean meal and free choice trace mineralized salt. Fecal egg counts (FEC), packed cell volume (PCV), and plasma aspartate aminotransferase (AST) activity were determined every 14 days and lambs weighed every 28 days. GIN infection reached a peak at Day 42 (high FEC, low PCV). COWP effectively reduced FEC on Days 0 and 42 compared with the previous week, but did not reduce FEC on Days 84 and 126 (treatment by time interaction, Pcopper in the liver on Day 155 were greater in COWP-treated lambs (Pcopper toxicity.

  6. Low-dose metformin improves pregnancy rate in in vitro fertilization repeaters without polycystic ovary syndrome: prediction of effectiveness by multiple parameters related to insulin resistance.

    Science.gov (United States)

    Jinno, Masao; Kondou, Kenichi; Teruya, Koji

    2010-01-01

    Insulin resistance is associated with aging and stress, both common among patients repeatedly failing to conceive with in vitro fertilization (IVF repeaters). In the present study we examined whether low-dose metformin could improve the outcome in IVF repeaters without polycystic ovary syndrome (PCOS). Study I was a preliminary clinical trial aiming at defining indications for therapy; study II was a prospective randomized study. The studies involved a university hospital and a private infertility clinic. We studied 232 women without PCOS who had failed at least twice to conceive by previous IVF. Metformin (500 mg/ day) was administered for 8 to 12 weeks before and during ovarian stimulation (metformin IVF). In study I, IVF outcomes with metformin (n = 33) were compared to outcomes without metformin of previous IVF in the same subjects. A discriminant score (DS) was determined from nine parameters assessed before metformin administration to predict achievement of ongoing pregnancy by metformin IVF. In study II (n = 199), ongoing pregnancy rates were compared prospectively between groups with/without metformin and with DS above/below 0.6647. Study I. Ongoing pregnancy rate improved significantly with metformin compared with previous IVF, and pregnancy correlated significantly with a DS at an optimal threshold of 0.6647 (sensitivity, 0.90; specificity, 0.91). Study II. Ongoing pregnancy and implantation rates were significantly higher in women with a DS above 0.6647 who received metformin (56% and 33%) compared with those having a DS below 0.6647 with metformin (14% and 11%) and those having a DS above/below 0.6647 without metformin (20% and 7.1%/15% and 11%, respectively). Low-dose metformin improved pregnancy rate in IVF repeaters without PCOS, probably by decreasing insulin resistance. Indication can be determined from insulin-resistance-related multiple parameters assessed before metformin administration.

  7. Comparison of Thromboemboli Prophylactic Effect of Aspirin and Low Dose Warfarin in Standard Risk Multiple Myeloma Patients that Treated with Regimens Containing Thalidomide

    Directory of Open Access Journals (Sweden)

    Seyed Amir Dadkhahi

    2017-05-01

    Full Text Available Abstract Background: Most of the current regimens in the treatment of multiple myeloma include thalidomide. Thalidomide is a modulator of the immune system and according to several studies, its main complication is thromboembolism. The aim of this study is to compare the thromboemboli prophylactic effect of aspirin and low dose warfarin in standard risk multiple myeloma patients that treated with regimens containing thalidomide. Materials and Methods: In this double- blind clinical trial study, sixty-six patients with multiple myeloma under treatment with thalidomide-containing regimens with standard risk for thromboembolism who were admitted to Khansari hospital, entered the study according to inclusion and exclusion criteria. The incidence of thromboembolism in these patients was evaluated. Results: Five patients in the warfarin group and 2 patients in the aspirin group had thromboemboli. Chi square analyses showed no significant difference between groups (p=0.635. Conclusion: The results showed that both drugs are effective in preventing thromboembolism and can be used as a prophylactic treatment.

  8. The effects of an intraperitoneal single low dose of ketamine in attenuating the postoperative skin/muscle incision and retraction-induced pain related to the inhibition of N-methyl-D-aspartate receptors in the spinal cord.

    Science.gov (United States)

    Shen, Yu; Xu, Li; Liu, Ming; Lei, Yishan; Gu, Xiaoping; Ma, Zhengliang

    2016-03-11

    Chronic postoperative pain (CPOP) is a common clinical problem which might be related to central sensitization. It has been widely accepted that NMDA (N-methyl-D-aspartate) receptors are among the triggers of central sensitization. Ketamine is a non-competitive NMDA receptor antagonist that is widely used in alleviating postoperative pain, but its effect on CPOP has been rarely reported. In the present study, the skin/muscle incision and retraction (SMIR) model was used to investigate the role of NMDARs in chronic postoperative pain and the effect of an intraperitoneal single low dose ketamine (10mg/kg) of attenuating SMIR-induced CPOP. We assessed pain behaviours after a SMIR operation by paw withdrawal threshold (PWMT) and paw withdrawal latency (PWMTL). Western blotting were performed to examine the role of NMDARs in SMIR-induced CPOP and the effect of ketamine on the expression and phosphorylation of NMDARs. The SMIR operation induced long-lasting mechanical hyperalgesia, and the up-regulation of phosphorylated NMDARs and total NMDARs at the spinal level. A single intraperitoneal administration of low dose ketamine (10mg/kg) during surgery alleviated pain behaviors and inhibited the up-regulation of phosphorylated NMDARs and total NMDARs. Our datas suggested that NMDARs play important roles in SMIR-induced CPOP. A single intraperitoneal low dose of ketamine could attenuate SMIR-induced CPOP, which might be associated with the inhibition of NMDARs. Our finding might provide a new, simple method of addressing CPOP. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. 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

  10. 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.)

  11. Inter-observer agreement for the evaluation of bone involvement on Whole Body Low Dose Computed Tomography (WBLDCT) in Multiple Myeloma (MM)

    International Nuclear Information System (INIS)

    Zacchino, M.; Minetti, V.; Dore, R.; Calliada, F.; Bonaffini, P.A.; Nasatti, A.; Sironi, S.; Corso, A.; Tinelli, C.

    2015-01-01

    We aimed to assess inter-observer agreement in bone involvement evaluation and define accuracy and reproducibility of MDCT images analysis in Multiple Myeloma (MM), by comparing two acquisition protocols at two different institutions. A total of 100 MM patients underwent whole body low-dose computed tomography (WB-LDCT), with two protocols: Group I (50 patients), 80 kV and 200-230 mAs; Group II, 120 kV-40 mAs. Four readers (two experts) retrospectively reviewed 22 anatomical districts, reporting the following for each patient: 1) osteolytic lesions; 2) cortical bone integrity; 3) fractures; 4) risk of vertebral collapse; 5) hyperattenuating bone lesions; and 6) extraosseous extension. Inter-observer agreement (by all readers, expert and young observers and comparison of the two protocols) was then statistically analyzed. According to Cohen's criteria, inter-observer agreement among the four readers and between experts and residents was good for the detection of bone lesions and extra-medullary extension, and for the evaluation of risk of collapse and cortical integrity. There was good agreement when comparing the two protocols. A greater variability was found for the evaluation of hyperattenuating lesions and the presence of fractures. WB-LDCT represents a reproducible and reliable technique that is helpful for defining bone disease in MM patients, with partial influence of readers' experience. (orig.)

  12. Inter-observer agreement for the evaluation of bone involvement on Whole Body Low Dose Computed Tomography (WBLDCT) in Multiple Myeloma (MM)

    Energy Technology Data Exchange (ETDEWEB)

    Zacchino, M.; Minetti, V.; Dore, R.; Calliada, F. [University of Pavia, Fondazione IRCCS Policlinico San Matteo, Institute of Radiology, Pavia (Italy); Bonaffini, P.A.; Nasatti, A.; Sironi, S. [University of Milano Bicocca, San Gerardo Hospital, Department of Diagnostic Radiology, Monza (Italy); Corso, A. [University of Pavia, Fondazione IRCCS Policlinico San Matteo, Division of Hematology, Pavia (Italy); Tinelli, C. [University of Pavia, Fondazione IRCCS Policlinico San Matteo, Service of Biometry and Statistics, Pavia (Italy)

    2015-11-15

    We aimed to assess inter-observer agreement in bone involvement evaluation and define accuracy and reproducibility of MDCT images analysis in Multiple Myeloma (MM), by comparing two acquisition protocols at two different institutions. A total of 100 MM patients underwent whole body low-dose computed tomography (WB-LDCT), with two protocols: Group I (50 patients), 80 kV and 200-230 mAs; Group II, 120 kV-40 mAs. Four readers (two experts) retrospectively reviewed 22 anatomical districts, reporting the following for each patient: 1) osteolytic lesions; 2) cortical bone integrity; 3) fractures; 4) risk of vertebral collapse; 5) hyperattenuating bone lesions; and 6) extraosseous extension. Inter-observer agreement (by all readers, expert and young observers and comparison of the two protocols) was then statistically analyzed. According to Cohen's criteria, inter-observer agreement among the four readers and between experts and residents was good for the detection of bone lesions and extra-medullary extension, and for the evaluation of risk of collapse and cortical integrity. There was good agreement when comparing the two protocols. A greater variability was found for the evaluation of hyperattenuating lesions and the presence of fractures. WB-LDCT represents a reproducible and reliable technique that is helpful for defining bone disease in MM patients, with partial influence of readers' experience. (orig.)

  13. Diagnostic value of whole-body low-dose computed tomography (WBLDCT) in bone lesions detection in patients with multiple myeloma (MM)

    Energy Technology Data Exchange (ETDEWEB)

    Ippolito, Davide, E-mail: davide.atena@tiscalinet.it [School of Medicine, University of Milano-Bicocca, Via Pergolesi 33, 20900 Monza (MB) (Italy); Department of Diagnostic Radiology, H. San Gerardo, Via Pergolesi 33, 20900 Monza (MB) (Italy); Besostri, Valeria, E-mail: valeriabesostri@gmail.com [School of Medicine, University of Milano-Bicocca, Via Pergolesi 33, 20900 Monza (MB) (Italy); Department of Diagnostic Radiology, H. San Gerardo, Via Pergolesi 33, 20900 Monza (MB) (Italy); Bonaffini, Pietro Andrea, E-mail: pa.bonaffini@gmail.com [School of Medicine, University of Milano-Bicocca, Via Pergolesi 33, 20900 Monza (MB) (Italy); Department of Diagnostic Radiology, H. San Gerardo, Via Pergolesi 33, 20900 Monza (MB) (Italy); Rossini, Fausto, E-mail: valeriabesostri@hotmail.it [Department of Hematology, H. San Gerardo, Via Pergolesi 33, 20900 Monza (MB) (Italy); Di Lelio, Alessandro, E-mail: valebeso@libero.it [Department of Diagnostic Radiology, H. San Gerardo, Via Pergolesi 33, 20900 Monza (MB) (Italy); Sironi, Sandro, E-mail: sandrosironi@libero.it [School of Medicine, University of Milano-Bicocca, Via Pergolesi 33, 20900 Monza (MB) (Italy); Department of Diagnostic Radiology, H. San Gerardo, Via Pergolesi 33, 20900 Monza (MB) (Italy)

    2013-12-01

    Purpose: To assess the role of whole-body low-dose computed tomography (WBLDCT) in the diagnosis and staging of patients with suspicion of multiple myeloma (MM). Materials and methods: A total of 138 patients (76 male and 62 female; mean age 63.5 years, range 50–81 years), with early MM, underwent WBLDCT protocol study, performed on 16-slice scanner (Brilliance, Philips Medical System, Eindhoven, The Netherlands): tube voltage 120 kV; tube current time product 40 mAs. Diagnosis of osteolytic lesions was performed on the basis of axial and multiplanar reformatted images, whereas the assessment of spinal misalignment and fracture was done by using multiplanar reformatted images. The overall dose delivered to each patient was 4.2 mSv. Every patient gave personal informed consent, as required by our institution guidelines. Results: The diagnosis was established either by histopathology or imaging follow-up (size increase of over a period time). In all 138 patients, image resolution was diagnostic, enabling correct classification of multiple myeloma patients. WBLDCT showed a total of 328 pathologic bone findings in 81/138 patients. CT scanning resulted in complete evaluation of the bone lesions in these areas of the skeleton: skull (42), humerus (15), femur (20), ribs (7), scapulae (13), pelvis (35), clavicle (13), sternum (10), cervical (39), dorsal (65), lombar (48) and sacral rachis (21). In 40/81 bone involvement detected by CT was the only CRAB criterion present. Furthermore, WBLDCT demonstrated pleuro-pulmonary lesions in 20 patients (11 infective, 9 as MM localizations) and 1 renal neoplasia. Conclusion: WBLDCT, detecting bone marrow localizations and demonstrating extra-osseous findings, with a fast scanning time and high resolution images, is a reliable imaging-based tool for a proper management of MM patients.

  14. Impact of prior treatment and depth of response on survival in MM-003, a randomized phase 3 study comparing pomalidomide plus low-dose dexamethasone versus high-dose dexamethasone in relapsed/refractory multiple myeloma

    Science.gov (United States)

    San Miguel, Jesus F.; Weisel, Katja C.; Song, Kevin W.; Delforge, Michel; Karlin, Lionel; Goldschmidt, Hartmut; Moreau, Philippe; Banos, Anne; Oriol, Albert; Garderet, Laurent; Cavo, Michele; Ivanova, Valentina; Alegre, Adrian; Martinez-Lopez, Joaquin; Chen, Christine; Renner, Christoph; Bahlis, Nizar Jacques; Yu, Xin; Teasdale, Terri; Sternas, Lars; Jacques, Christian; Zaki, Mohamed H.; Dimopoulos, Meletios A.

    2015-01-01

    Pomalidomide is a distinct oral IMiD® immunomodulatory agent with direct antimyeloma, stromal-support inhibitory, and immunomodulatory effects. The pivotal, multicenter, open-label, randomized phase 3 trial MM-003 compared pomalidomide + low-dose dexamethasone vs high-dose dexamethasone in 455 patients with refractory or relapsed and refractory multiple myeloma after failure of bortezomib and lenalidomide treatment. Initial results demonstrated significantly longer progression-free survival and overall survival with an acceptable tolerability profile for pomalidomide + low-dose dexamethasone vs high-dose dexamethasone. This secondary analysis describes patient outcomes by treatment history and depth of response. Pomalidomide + low-dose dexamethasone significantly prolonged progression-free survival and favored overall survival vs high-dose dexamethasone for all subgroups analyzed, regardless of prior treatments or refractory status. Both univariate and multivariate analyses showed that no variable relating to either the number (≤ or > 3) or type of prior treatment was a significant predictor of progression-free survival or overall survival. No cross-resistance with prior lenalidomide or thalidomide treatment was observed. Patients achieving a minimal response or better to pomalidomide + low-dose dexamethasone treatment experienced a survival benefit, which was even higher in those achieving at least a partial response (17.2 and 19.9 months, respectively, as compared with 7.5 months for patients with less than minimal response). These data suggest that pomalidomide + low-dose dexamethasone should be considered a standard of care in patients with refractory or relapsed and refractory multiple myeloma regardless of prior treatment. ClinicalTrials.gov: NCT01311687; EudraCT: 2010-019820-30. PMID:26160879

  15. 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.)

  16. Reconstruction of multiple line source attenuation maps

    International Nuclear Information System (INIS)

    Celler, A.; Sitek, A.; Harrop, R.

    1996-01-01

    A simple configuration for a transmission source for the single photon emission computed tomography (SPECT) was proposed, which utilizes a series of collimated line sources parallel to the axis of rotation of a camera. The detector is equipped with a standard parallel hole collimator. We have demonstrated that this type of source configuration can be used to generate sufficient data for the reconstruction of the attenuation map when using 8-10 line sources spaced by 3.5-4.5 cm for a 30 x 40cm detector at 65cm distance from the sources. Transmission data for a nonuniform thorax phantom was simulated, then binned and reconstructed using filtered backprojection (FBP) and iterative methods. The optimum maps are obtained with data binned into 2-3 bins and FBP reconstruction. The activity in the source was investigated for uniform and exponential activity distributions, as well as the effect of gaps and overlaps of the neighboring fan beams. A prototype of the line source has been built and the experimental verification of the technique has started

  17. Multiple attenuation to reflection seismic data using Radon filter and Wave Equation Multiple Rejection (WEMR) method

    Energy Technology Data Exchange (ETDEWEB)

    Erlangga, Mokhammad Puput [Geophysical Engineering, Institut Teknologi Bandung, Ganesha Street no.10 Basic Science B Buliding fl.2-3 Bandung, 40132, West Java Indonesia puput.erlangga@gmail.com (Indonesia)

    2015-04-16

    Separation between signal and noise, incoherent or coherent, is important in seismic data processing. Although we have processed the seismic data, the coherent noise is still mixing with the primary signal. Multiple reflections are a kind of coherent noise. In this research, we processed seismic data to attenuate multiple reflections in the both synthetic and real seismic data of Mentawai. There are several methods to attenuate multiple reflection, one of them is Radon filter method that discriminates between primary reflection and multiple reflection in the τ-p domain based on move out difference between primary reflection and multiple reflection. However, in case where the move out difference is too small, the Radon filter method is not enough to attenuate the multiple reflections. The Radon filter also produces the artifacts on the gathers data. Except the Radon filter method, we also use the Wave Equation Multiple Elimination (WEMR) method to attenuate the long period multiple reflection. The WEMR method can attenuate the long period multiple reflection based on wave equation inversion. Refer to the inversion of wave equation and the magnitude of the seismic wave amplitude that observed on the free surface, we get the water bottom reflectivity which is used to eliminate the multiple reflections. The WEMR method does not depend on the move out difference to attenuate the long period multiple reflection. Therefore, the WEMR method can be applied to the seismic data which has small move out difference as the Mentawai seismic data. The small move out difference on the Mentawai seismic data is caused by the restrictiveness of far offset, which is only 705 meter. We compared the real free multiple stacking data after processing with Radon filter and WEMR process. The conclusion is the WEMR method can more attenuate the long period multiple reflection than the Radon filter method on the real (Mentawai) seismic data.

  18. Whole-body low-dose computed tomography in multiple myeloma staging: Superior diagnostic performance in the detection of bone lesions, vertebral compression fractures, rib fractures and extraskeletal findings compared to radiography with similar radiation exposure.

    Science.gov (United States)

    Lambert, Lukas; Ourednicek, Petr; Meckova, Zuzana; Gavelli, Giampaolo; Straub, Jan; Spicka, Ivan

    2017-04-01

    The primary objective of the present prospective study was to compare the diagnostic performance of conventional radiography (CR) and whole-body low-dose computed tomography (WBLDCT) with a comparable radiation dose reconstructed using hybrid iterative reconstruction technique, in terms of the detection of bone lesions, skeletal fractures, vertebral compressions and extraskeletal findings. The secondary objective was to evaluate lesion attenuation in relation to its size. A total of 74 patients underwent same-day skeletal survey by CR and WBLDCT. In CR and WBLDCT, two readers assessed the number of osteolytic lesions at each region and stage according to the International Myeloma Working Group (IMWG) criteria. A single reader additionally assessed extraskeletal findings and their significance, the number of vertebral compressions and bone fractures. The radiation exposure was 2.7±0.9 mSv for WBLDCT and 2.5±0.9 mSv for CR (P=0.054). CR detected bone involvement in 127 out of 486 regions (26%; Prib fractures compared with CR (188 vs. 47; Pfractures, vertebral compressions and extraskeletal findings, which results in up- or downstaging in 24% patients according to the IMWG criteria. The attenuation of osteolytic lesions can be measured with the avoidance of the partial volume effect.

  19. 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

  20. Elotuzumab in combination with thalidomide and low-dose dexamethasone: a phase 2 single-arm safety study in patients with relapsed/refractory multiple myeloma.

    Science.gov (United States)

    Mateos, María-Victoria; Granell, Miguel; Oriol, Albert; Martinez-Lopez, Joaquin; Blade, Joan; Hernandez, Miguel T; Martín, Jesus; Gironella, Mercedes; Lynch, Mark; Bleickardt, Eric; Paliwal, Prashni; Singhal, Anil; San-Miguel, Jesus

    2016-11-01

    Elotuzumab is an immunostimulatory, humanized immunoglobulin G1 monoclonal antibody that selectively targets and kills signalling lymphocytic activation molecule family member 7-expressing myeloma cells. We evaluated the safety and tolerability of elotuzumab 10 mg/kg combined with thalidomide 50-200 mg and dexamethasone 40 mg (with/without cyclophosphamide 50 mg) in patients with relapsed/refractory multiple myeloma (RRMM). The primary endpoint was the proportion of grade ≥3 non-haematological adverse events (AEs); other endpoints included the number of dose reductions/discontinuations and efficacy. Forty patients were treated, who had a median of three previous therapies, including bortezomib (98%) and lenalidomide (73%). Grade ≥3 non-haematological AEs were reported in 63% of patients, most commonly asthenia (35%) and peripheral oedema (25%). Six (15%) patients had an infusion reaction. Twenty-six (65%) patients had ≥1 dose reduction/discontinuation due to an AE, none related to elotuzumab. Overall response rate was 38%; median progression-free survival was 3·9 months. Median overall survival was 16·3 months and the 1-year survival rate was 63%. Minimal incremental toxicity was observed with addition of elotuzumab to thalidomide/dexamethasone with or without cyclophosphamide, and efficacy data suggest clinical benefit in a highly pre-treated population. Elotuzumab combined with thalidomide may provide an additional treatment option for patients with RRMM. © 2016 John Wiley & Sons Ltd.

  1. Gamma knife radiosurgery for acoustic schwannomas. An analysis of the method of low dose and conformal multiple shots with smaller collimator

    International Nuclear Information System (INIS)

    Fukuoka, Seiji; Takanashi, Masami; Hojo, Atsufumi; Konishi, Masanori; Nakamura, Hirohiko

    2003-01-01

    The purpose of this study was to analyze tumor control and possible complications of gamma knife radiosurgery (GKRS) in patients with acoustic schwannomas treated using low marginal dose and conformal multiple shots with smaller collimators to fit irregular tumor shapes. The authors evaluated 183 patients with follow-up periods ranging from 3 to 11 years. Marginal doses were 9 to 15 Gy (median 12 Gy), with corresponding treatment volumes being between 0.1 and 18.7 ml (median 1.8 ml). The number of isocenter varied from 2 to 24 shots (median 9 shots). The actuarial tumor control rate (resection-free survival) was 96.5%. Useful hearing, trigeminal and facial functions were preserved at 75%, 97.4%, and 100%, respectively. Hydrocephalus was recognized in 5.7% of all patients, and seems to occur in cases with medium sized tumors where mild ventricular enlargement is evident prior to treatment. GKRS proves to be a safe and effective therapy for small to medium sized tumors. However, the indication for larger sized tumors (diameter 3+ cm) should be carefully considered, larger tumors being less easy to control and liable to cause ataxia due to transient expansion. (author)

  2. 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

  3. A murine model of type 2 diabetes mellitus developed using a combination of high fat diet and multiple low doses of streptozotocin treatment mimics the metabolic characteristics of type 2 diabetes mellitus in humans.

    Science.gov (United States)

    Nath, Sayantan; Ghosh, Sankar Kumar; Choudhury, Yashmin

    A murine model of type 2 diabetes mellitus was used to compare the antidiabetic effects of the dipeptidyl peptidase-4 (DPP4) inhibitor vildagliptin and biguanide, metformin. Swiss albino mice (n=20 males; n=25 females) were given high fat diet (HFD) ad libitum for 3weeks followed by low dose (40mgkg -1 body weight, bw daily) of streptozotocin (STZ) intraperitoneally five times from the 22nd day of treatment onwards, with HFD continued up to 26th day. Controls (n=15 males; n=15 females) were fed normal balanced diet without administration of STZ. Successful induction of diabetes mellitus was confirmed by testing for fasting blood glucose, intraperitoneal glucose tolerance and intraperitoneal insulin sensitivity. Diabetic mice were administered vildagliptin (10mgkg -1 bw daily) and metformin (50mgkg -1 bw daily) orally for 4weeks. Control, diabetic, vildagliptin and metformin-treated diabetic mice were evaluated for alterations in lipid profile using blood serum and histopathology and oxidative stress using tissues including liver, kidney and heart. Diabetic mice showed significant alterations in lipid profile, tissue histopathology, impaired glucose tolerance, lower insulin sensitivity and elevated lipid peroxidation and protein carbonylation, with depressed catalase activity, when compared to age and gender-matched controls. Metformin and vildagliptin ameliorated the abovementioned diabetic conditions, with vildagliptin found to be more effective. A murine model developed by the combination of HFD and multiple low dose of STZ mimics the metabolic characteristics of type 2 diabetes mellitus in humans, and may be useful for antidiabetic drug screening. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. 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.

  5. 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.

  6. African Swine Fever Virus Georgia 2007 with a Deletion of Virulence-Associated Gene 9GL (B119L), when Administered at Low Doses, Leads to Virus Attenuation in Swine and Induces an Effective Protection against Homologous Challenge.

    Science.gov (United States)

    O'Donnell, Vivian; Holinka, Lauren G; Krug, Peter W; Gladue, Douglas P; Carlson, Jolene; Sanford, Brenton; Alfano, Marialexia; Kramer, Edward; Lu, Zhiqiang; Arzt, Jonathan; Reese, Bo; Carrillo, Consuelo; Risatti, Guillermo R; Borca, Manuel V

    2015-08-01

    African swine fever virus (ASFV) is the etiological agent of an often lethal disease of domestic pigs. Disease control strategies have been hampered by the unavailability of vaccines against ASFV. Since its introduction in the Republic of Georgia, a highly virulent virus, ASFV Georgia 2007 (ASFV-G), has caused an epizootic that spread rapidly into Eastern European countries. Currently no vaccines are available or under development to control ASFV-G. In the past, genetically modified ASFVs harboring deletions of virulence-associated genes have proven attenuated in swine, inducing protective immunity against challenge with homologous parental viruses. Deletion of the gene 9GL (open reading frame [ORF] B119L) in highly virulent ASFV Malawi-Lil-20/1 produced an attenuated phenotype even when administered to pigs at 10(6) 50% hemadsorption doses (HAD50). Here we report the construction of a genetically modified ASFV-G strain (ASFV-G-Δ9GLv) harboring a deletion of the 9GL (B119L) gene. Like Malawi-Lil-20/1-Δ9GL, ASFV-G-Δ9GL showed limited replication in primary swine macrophages. However, intramuscular inoculation of swine with 10(4) HAD50 of ASFV-G-Δ9GL produced a virulent phenotype that, unlike Malawi-Lil-20/1-Δ9GL, induced a lethal disease in swine like parental ASFV-G. Interestingly, lower doses (10(2) to 10(3) HAD50) of ASFV-G-Δ9GL did not induce a virulent phenotype in swine and when challenged protected pigs against disease. A dose of 10(2) HAD50 of ASFV-G-Δ9GLv conferred partial protection when pigs were challenged at either 21 or 28 days postinfection (dpi). An ASFV-G-Δ9GL HAD50 of 10(3) conferred partial and complete protection at 21 and 28 dpi, respectively. The information provided here adds to our recent report on the first attempts toward experimental vaccines against ASFV-G. The main problem for controlling ASF is the lack of vaccines. Studies on ASFV virulence lead to the production of genetically modified attenuated viruses that induce protection

  7. Multiple-energy tissue-cancellation applications of a digital beam attenuator to chest radiography

    International Nuclear Information System (INIS)

    Dobbins, J.T. III.

    1985-01-01

    The digitally-formed primary beam attenuator (DBA) spatially modulates the x-ray fluence incident upon the patient to selectively attenuate regions of interest. The DBA attenuating mask is constructed from CeO 2 powder by a modified printing technique and uses image information from an initial low-dose exposure. Two tissue-cancellation imaging techniques are investigated with the DBA: (1) energy-dependent information is used to form a beam attenuator that attenuates specific tissues in the primary x-ray beam for tissue-cancelled film radiography; (2) the beam attenuator is used to improve image signal-to-noise and scattered radiation properties in traditional energy-subtraction tissue-cancellation imaging with digital detectors. The tissue-cancellation techniques in the primary x-ray beam were capable of adequately removing either soft-tissue or bone from the final compensated film radiograph when using a phantom with well defined soft-tissue and bone sections. However, when tried on an anthropomorphic chest phantom the results were adequate for cancellation of large soft tissue structures, but unsatisfactory for cancellation of bony structures such as the ribs, because of the limited spatial frequency content of the attenuating mask. The second technique (with digital detectors) showed improved uniformity of image signal-to-noise and a two-fold increase in soft-tissue nodule contrast due to improved scattered radiation properties. The tissue-cancelled images contained residual image contributions from the presence of the attenuating mask, but this residual may be correctable by future algorithms

  8. 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

  9. 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

  10. Reduced oxygen enhancement ratio at low doses

    International Nuclear Information System (INIS)

    Palcic, B.; Skarsgard, L.D.

    1984-01-01

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

  11. LOW DOSE RISK, DECISIONS, and RISK COMMUNICATION

    International Nuclear Information System (INIS)

    Flynn, James

    2002-01-01

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

  12. 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

  13. Simple pulmonary eosinophilia detected at low-dose CT for lung cancer screening

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Kyung Nyeo; Bae, Kyung Soo; Kim, Ho Cheol [Gyeongsang National University Hospital, Jinju (Korea, Republic of)] (and others)

    2006-05-15

    The aim of this study was to evaluate the frequency, radiologic findings and clinical significance of the simple pulmonary eosinophilia (SPE) that was diagnosed among the asymptomatic patients who underwent low-dose CT scans for the early detection of lung cancer. From June 2003 to May 2005, 1,239 asymptomatic patients (1,275 examinations) who visited the health promotion center in our hospital and who underwent low-dose CT were enrolled in this study. SPE was defined as the presence of > 500 eosinophils per microliter of peripheral blood and the presence of abnormal parenchymal lesions such as nodules, airspace consolidation or areas of ground-glass attenuation (GGA) on CT, and there was spontaneous resolution or migration of the lesions on the follow-up examination. We analyzed the CT findings of SPE and we investigated the relationship between the occurrence of SPE and the season, smoking and the presence of parasite infestation. 36 patients were finally diagnosed as having SPE; this was 24% of the 153 patients who were diagnosed with parasite infestation and 2.8% of the total low-dose CT scans. These 36 patients consisted of 31 men and 5 women with a mean age 45.7 years. There was no significant relationship between SPE and the presence of parasite infestation, smoking or gender. Among the patients with peripheral blood eosinophilia, the eosinophil count was significantly higher in the patients with SPE than that in the patients without pulmonary infiltration ({rho} < 0.05). SPE more frequently occurred in winter and spring than in summer and autumn ({rho} < 0.05). The CT findings were single or multiple nodules in 18 patients, nodules and focal GGA in 9 patients and GGA only in 9 patients. Most of the nodules were less than 10 mm (88%, 49/56) in diameter and they showed an ill-defined margin (82%, n = 46); 30% of the nodules (n = 17) showed a halo around them. Simple pulmonary eosinophilia can be suggested as the cause if single or multiple ill-defined nodules

  14. Simple pulmonary eosinophilia detected at low-dose CT for lung cancer screening

    International Nuclear Information System (INIS)

    Jeon, Kyung Nyeo; Bae, Kyung Soo; Kim, Ho Cheol

    2006-01-01

    The aim of this study was to evaluate the frequency, radiologic findings and clinical significance of the simple pulmonary eosinophilia (SPE) that was diagnosed among the asymptomatic patients who underwent low-dose CT scans for the early detection of lung cancer. From June 2003 to May 2005, 1,239 asymptomatic patients (1,275 examinations) who visited the health promotion center in our hospital and who underwent low-dose CT were enrolled in this study. SPE was defined as the presence of > 500 eosinophils per microliter of peripheral blood and the presence of abnormal parenchymal lesions such as nodules, airspace consolidation or areas of ground-glass attenuation (GGA) on CT, and there was spontaneous resolution or migration of the lesions on the follow-up examination. We analyzed the CT findings of SPE and we investigated the relationship between the occurrence of SPE and the season, smoking and the presence of parasite infestation. 36 patients were finally diagnosed as having SPE; this was 24% of the 153 patients who were diagnosed with parasite infestation and 2.8% of the total low-dose CT scans. These 36 patients consisted of 31 men and 5 women with a mean age 45.7 years. There was no significant relationship between SPE and the presence of parasite infestation, smoking or gender. Among the patients with peripheral blood eosinophilia, the eosinophil count was significantly higher in the patients with SPE than that in the patients without pulmonary infiltration (ρ < 0.05). SPE more frequently occurred in winter and spring than in summer and autumn (ρ < 0.05). The CT findings were single or multiple nodules in 18 patients, nodules and focal GGA in 9 patients and GGA only in 9 patients. Most of the nodules were less than 10 mm (88%, 49/56) in diameter and they showed an ill-defined margin (82%, n = 46); 30% of the nodules (n = 17) showed a halo around them. Simple pulmonary eosinophilia can be suggested as the cause if single or multiple ill-defined nodules or

  15. 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.)

  16. 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.

  17. 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)

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

    Science.gov (United States)

    Chopra, Pradeep; Cooper, Mark S

    2013-06-01

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

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

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  20. The Research of Multiple Attenuation Based on Feedback Iteration and Independent Component Analysis

    Science.gov (United States)

    Xu, X.; Tong, S.; Wang, L.

    2017-12-01

    How to solve the problem of multiple suppression is a difficult problem in seismic data processing. The traditional technology for multiple attenuation is based on the principle of the minimum output energy of the seismic signal, this criterion is based on the second order statistics, and it can't achieve the multiple attenuation when the primaries and multiples are non-orthogonal. In order to solve the above problems, we combine the feedback iteration method based on the wave equation and the improved independent component analysis (ICA) based on high order statistics to suppress the multiple waves. We first use iterative feedback method to predict the free surface multiples of each order. Then, in order to predict multiples from real multiple in amplitude and phase, we design an expanded pseudo multi-channel matching filtering method to get a more accurate matching multiple result. Finally, we present the improved fast ICA algorithm which is based on the maximum non-Gauss criterion of output signal to the matching multiples and get better separation results of the primaries and the multiples. The advantage of our method is that we don't need any priori information to the prediction of the multiples, and can have a better separation result. The method has been applied to several synthetic data generated by finite-difference model technique and the Sigsbee2B model multiple data, the primaries and multiples are non-orthogonal in these models. The experiments show that after three to four iterations, we can get the perfect multiple results. Using our matching method and Fast ICA adaptive multiple subtraction, we can not only effectively preserve the effective wave energy in seismic records, but also can effectively suppress the free surface multiples, especially the multiples related to the middle and deep areas.

  1. Low dose irradiation reduces cancer mortality rates

    International Nuclear Information System (INIS)

    Luckey, T.D.

    2000-01-01

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

  2. 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

  3. 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

  4. 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)

  5. 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.’

  6. 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

  7. 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

  8. 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.

  9. 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)

  10. 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

  11. 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)

  12. 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

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

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  14. 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

  15. 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)

  16. 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)

  17. 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

  18. 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.)

  19. 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)

  20. Multiple scattering and attenuation corrections in Deep Inelastic Neutron Scattering experiments

    International Nuclear Information System (INIS)

    Dawidowski, J; Blostein, J J; Granada, J R

    2006-01-01

    Multiple scattering and attenuation corrections in Deep Inelastic Neutron Scattering experiments are analyzed. The theoretical basis of the method is stated, and a Monte Carlo procedure to perform the calculation is presented. The results are compared with experimental data. The importance of the accuracy in the description of the experimental parameters is tested, and the implications of the present results on the data analysis procedures is examined

  1. 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

  2. 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

  3. 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...

  4. 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

  5. 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

  6. 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.)

  7. 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.

  8. Increased interleukin-1β levels following low dose MDMA induces tolerance against the 5-HT neurotoxicity produced by challenge MDMA

    Science.gov (United States)

    2011-01-01

    Background Preconditioning is a phenomenon by which tolerance develops to injury by previous exposure to a stressor of mild severity. Previous studies have shown that single or repeated low dose MDMA can attenuate 5-HT transporter loss produced by a subsequent neurotoxic dose of the drug. We have explored the mechanism of delayed preconditioning by low dose MDMA. Methods Male Dark Agouti rats were given low dose MDMA (3 mg/kg, i.p.) 96 h before receiving neurotoxic MDMA (12.5 mg/kg, i.p.). IL-1β and IL1ra levels and 5-HT transporter density in frontal cortex were quantified at 1 h, 3 h or 7 days. IL-1β, IL-1ra and IL-1RI were determined between 3 h and 96 h after low dose MDMA. sIL-1RI combined with low dose MDMA or IL-1β were given 96 h before neurotoxic MDMA and toxicity assessed 7 days later. Results Pretreatment with low dose MDMA attenuated both the 5-HT transporter loss and elevated IL-1β levels induced by neurotoxic MDMA while producing an increase in IL-1ra levels. Low dose MDMA produced an increase in IL-1β at 3 h and in IL-1ra at 96 h. sIL-1RI expression was also increased after low dose MDMA. Coadministration of sIL-1RI (3 μg, i.c.v.) prevented the protection against neurotoxic MDMA provided by low dose MDMA. Furthermore, IL-1β (2.5 pg, intracortical) given 96 h before neurotoxic MDMA protected against the 5-HT neurotoxicity produced by the drug, thus mimicking preconditioning. Conclusions These results suggest that IL-1β plays an important role in the development of delayed preconditioning by low dose MDMA. PMID:22114930

  9. Increased interleukin-1β levels following low dose MDMA induces tolerance against the 5-HT neurotoxicity produced by challenge MDMA

    Directory of Open Access Journals (Sweden)

    Mayado Andrea

    2011-11-01

    Full Text Available Abstract Background Preconditioning is a phenomenon by which tolerance develops to injury by previous exposure to a stressor of mild severity. Previous studies have shown that single or repeated low dose MDMA can attenuate 5-HT transporter loss produced by a subsequent neurotoxic dose of the drug. We have explored the mechanism of delayed preconditioning by low dose MDMA. Methods Male Dark Agouti rats were given low dose MDMA (3 mg/kg, i.p. 96 h before receiving neurotoxic MDMA (12.5 mg/kg, i.p.. IL-1β and IL1ra levels and 5-HT transporter density in frontal cortex were quantified at 1 h, 3 h or 7 days. IL-1β, IL-1ra and IL-1RI were determined between 3 h and 96 h after low dose MDMA. sIL-1RI combined with low dose MDMA or IL-1β were given 96 h before neurotoxic MDMA and toxicity assessed 7 days later. Results Pretreatment with low dose MDMA attenuated both the 5-HT transporter loss and elevated IL-1β levels induced by neurotoxic MDMA while producing an increase in IL-1ra levels. Low dose MDMA produced an increase in IL-1β at 3 h and in IL-1ra at 96 h. sIL-1RI expression was also increased after low dose MDMA. Coadministration of sIL-1RI (3 μg, i.c.v. prevented the protection against neurotoxic MDMA provided by low dose MDMA. Furthermore, IL-1β (2.5 pg, intracortical given 96 h before neurotoxic MDMA protected against the 5-HT neurotoxicity produced by the drug, thus mimicking preconditioning. Conclusions These results suggest that IL-1β plays an important role in the development of delayed preconditioning by low dose MDMA.

  10. The linear attenuation coefficients as features of multiple energy CT image classification

    International Nuclear Information System (INIS)

    Homem, M.R.P.; Mascarenhas, N.D.A.; Cruvinel, P.E.

    2000-01-01

    We present in this paper an analysis of the linear attenuation coefficients as useful features of single and multiple energy CT images with the use of statistical pattern classification tools. We analyzed four CT images through two pointwise classifiers (the first classifier is based on the maximum-likelihood criterion and the second classifier is based on the k-means clustering algorithm) and one contextual Bayesian classifier (ICM algorithm - Iterated Conditional Modes) using an a priori Potts-Strauss model. A feature extraction procedure using the Jeffries-Matusita (J-M) distance and the Karhunen-Loeve transformation was also performed. Both the classification and the feature selection procedures were found to be in agreement with the predicted discrimination given by the separation of the linear attenuation coefficient curves for different materials

  11. 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

  12. 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.

  13. 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

  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. Exposures at low doses and biological effects of ionizing radiations

    International Nuclear Information System (INIS)

    Masse, R.

    2000-01-01

    cellular responses reflected in fact the results of multiple cellular interactions. Following the conclusion of the French Academy of medicine, LNT modelling resulted in public anxiety by changing an hypothetical residual risk at low doses into a real one, calling on regulators, continuously, for a more and more severe control of tiny sources which may result in considerable collective doses when considered as being exposed to billions of people for hundreds of years. Examples were provided that showed that the perception of risk of radioactive sources was not related to the severity of the risk itself but to the importance attributed to the situation by the media. In some instances, such as those resulting from the loss of gamma-graphy sources, it resulted in a dangerous underestimate of the necessary remedial actions. (author)

  17. Partial Sleep Deprivation Attenuates the Positive Affective System: Effects Across Multiple Measurement Modalities.

    Science.gov (United States)

    Finan, Patrick H; Quartana, Phillip J; Remeniuk, Bethany; Garland, Eric L; Rhudy, Jamie L; Hand, Matthew; Irwin, Michael R; Smith, Michael T

    2017-01-01

    Ample behavioral and neurobiological evidence links sleep and affective functioning. Recent self-report evidence suggests that the affective problems associated with sleep loss may be stronger for positive versus negative affective state and that those effects may be mediated by changes in electroencepholographically measured slow wave sleep (SWS). In the present study, we extend those preliminary findings using multiple measures of affective functioning. In a within-subject randomized crossover experiment, we tested the effects of one night of sleep continuity disruption via forced awakenings (FA) compared to one night of uninterrupted sleep (US) on three measures of positive and negative affective functioning: self-reported affective state, affective pain modulation, and affect-biased attention. The study was set in an inpatient clinical research suite. Healthy, good sleeping adults (N = 45) were included. Results indicated that a single night of sleep continuity disruption attenuated positive affective state via FA-induced reductions in SWS. Additionally, sleep continuity disruption attenuated the inhibition of pain by positive affect as well as attention bias to positive affective stimuli. Negative affective state, negative affective pain facilitation, nor negative attention bias were altered by sleep continuity disruption. The present findings, observed across multiple measures of affective function, suggest that sleep continuity disruption has a stronger influence on the positive affective system relative to the negative affective affective system. © Sleep Research Society 2016. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

  18. ATTENUATION OF DIFFRACTED MULTIPLES WITH AN APEX-SHIFTED TANGENT-SQUARED RADON TRANSFORM IN IMAGE SPACE

    Directory of Open Access Journals (Sweden)

    Alvarez Gabriel

    2006-12-01

    Full Text Available In this paper, we propose a method to attenuate diffracted multiples with an apex-shifted tangent-squared Radon transform in angle domain common image gathers (ADCIG . Usually, where diffracted multiples are a problem, the wave field propagation is complex and the moveout of primaries and multiples in data space is irregular. The method handles the complexity of the wave field propagation by wave-equation migration provided that migration velocities are reasonably accurate. As a result, the moveout of the multiples is well behaved in the ADCIGs. For 2D data, the apex-shifted tangent-squared Radon transform maps the 2D space image into a 3D space-cube model whose dimensions are depth, curvature and apex-shift distance.
    Well-corrected primaries map to or near the zero curvature plane and specularly-reflected multiples map to or near the zero apex-shift plane. Diffracted multiples map elsewhere in the cube according to their curvature and apex-shift distance. Thus, specularly reflected as well as diffracted multiples can be attenuated simultaneously. This approach is illustrated with a segment of a 2D seismic line over a large salt body in the Gulf of Mexico. It is shown that ignoring the apex shift compromises the attenuation of the diffracted multiples, whereas the approach proposed attenuates both the specularly-reflected and the diffracted multiples without compromising the primaries.

  19. 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.

  20. 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

  1. 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.

  2. Fast spine echo and fast fluid attenuated inversion recovery sequences in multiple sclerosis

    International Nuclear Information System (INIS)

    Paolillo, Andrea; Giugni, Elisabetta; Bozzao, Alessandro; Bastianello, Stefano

    1997-01-01

    Fast spin echo (FSE) and fast fluid attenuated inversion recovery (fast-FLAIR) sequences, were compared with conventional spin echo (CSE) in quantitating multiple sclerosis (MS) lesion burden. For each sequence, the total number and volume of MS lesions were calculated in 38 remitting multiple sclerosis patients using a semiautomated lesion detection program. Conventional spin echo, fast spin echo, and fast fluid attenuated inversion recovery image were reported on randomly and at different times by two expert observers. Interobserver differences, the time needed to quantitative multiple sclerosis lesions and lesion signal intensity (contrast-to-noise ratio and overall contrast) were considered. The lesions were classified by site into infratentorial, white matter and cortical/subcortical. A total of 2970 lesions with a volume of 961.7 cm 3 was calculated on conventional spin echo images. Fast spin echo images depicted fewer (16.6%; p < .005) and smaller (24.9%; p < .0001) lesions and the differences were statistically significant. Despite an overall nonsignificant reduction for fast-FLAIR images (-5% and 4.8% for lesion number and volume, respectively), significantly lower values (lesion number: p < 0.1; volume: p < .04)were observed for infratentorial lesions, while significantly higher values were seen for cortical/subcortical lesions (lesion number: p < .01; volume: p < .02). A higher lesion/white matter contrast (p < .002), a significant time saving for lesion burden quantitation (p < .05) and very low interobserver variability were found in favor of fast-FLAIR. Our data suggest that, despite the limitations regarding infratentorial lesions, fast-FLAIR sequences are indicated in R studies because of their good identification of cortical/subcortical lesions, almost complete interobserver agreement, higher contrast-to-noise ratio and limited time needed for semiautomated quantitation

  3. 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

  4. 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....

  5. 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....

  6. 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

  7. 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.

  8. 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.

  9. 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)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-07-01

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

  11. X-raying with low dose irradiation

    International Nuclear Information System (INIS)

    Malevich, E.E.; Kisel, E.M.; Shpita, I.D.; Lazovsky, A.S.

    2001-01-01

    With the purpose of the improvement of diagnostics quality and reduction of beam load on a patient in modern x-ray devices pulse x-raying is applied. It is based on the using of radiation pulses with various frequencies of intervals between them instead of continuous radiation. At pulse x-raying with the net control the principle of filling of an interval is used, when the information about the image, received with the last pulse, get into memory and is displayed before occurrence of other pulse. It creates impression of the continuous image even at low frequency of pulses. Due to the unique concept of the simultaneous (double) control, all of 3 parameters, which define the quality of the image (pressure(voltage), force of a current and length of a pulse), are adjusted automatically at each pulse, thus optimum adaptation to varied thickness of object during dynamic researches occurs. At x-raying pulse the presence of a free interval from x-ray radiation between two pulses results in the decrease of a radiation dose. Pulsing occurs some times per one second with equal intervals between pulses. Thus, the degree of decrease irradiation dose depends on duration of a pause between pulses. On the screen the image of last pulse before occurrence of the following is kept and repeats. The principle of x-raying pulse was realized in system Grid Controlled Fluoroscopy by the firm 'Philips Medi zin Systeme'. In the x-ray tube of this system inclusion and de energizing of radiation occurs directly on a source. Electron cloud is broken off by the special grid, which is located between the cathode and the anode and operates as a barrier. Thus the tube continues to be energized. In usual devices for pulses formation is used generator pulsation system, which at increase and attenuation of a x-ray pulse results in occurrence of the increasing and fading radiation which are not participating in the formation of the image, but creating beam load on the patient and the personnel. Thus

  12. 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)

  13. Multiple Lines Of Evidence Supporting Natural Attenuation: Lines Of Inquiry Supporting Monitored Natural Attenuation And Enhanced Attenuatin Of Chlorinated Solvents

    Energy Technology Data Exchange (ETDEWEB)

    Vangelas, Karen; Widemeirer, T. H.; Barden, M.J.; Dickson, W. Z.; Major, David

    2004-12-31

    The Department of Energy (DOE) is sponsoring an initiative to facilitate efficient, effective and responsible use of Monitored Natural Attenuation (MNA) and Enhanced Attenuation (EA) for chlorinated solvents. This Office of Environmental Management (EM) ''Alternative Project,'' focuses on providing scientific and policy support for MNA/EA. A broadly representative working group of scientists supports the project along with partnerships with regulatory organizations such as the Interstate Technology Regulatory Council (ITRC) and the United States Environmental Protection Agency (USEPA). The initial product of the technical working group was a summary report that articulated the conceptual approach and central scientific tenants of the project, and that identified a prioritized listing of technical targets for field research. This report documented the process in which: (1) scientific ground rules were developed, (2) lines of inquiry were identified and then critically evaluated, (3) promising applied research topics were highlighted in the various lines of inquiry, and (4) these were discussed and prioritized. The summary report will serve as a resource to guide management and decision making throughout the period of the subject MNA/EA Alternative Project. To support and more fully document the information presented in the summary report, the DOE is publishing a series of supplemental documents that present the full texts from the technical analyses within the various lines of inquiry (see listing). The following report--documenting our evaluation of the state of the science for the lines of evidence for supporting decision-making for MNA--is one of those supplemental documents.

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

    International Nuclear Information System (INIS)

    Ogata, Hiromitsu; Magae, Junji

    2008-01-01

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

  15. 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

  16. 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

  17. 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)

  18. 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.

  19. 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)

  20. 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

  1. Attenuation of virus production at high multiplicities of infection in Aureococcus anophagefferens

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Christopher M.; Bidle, Kay D., E-mail: bidle@marine.rutgers.edu

    2014-10-15

    Infection dynamics (saturation kinetics, infection efficiency, adsorption and burst size) for the Aureococcus anophagefferens-Brown Tide virus (AaV) system were investigated using susceptible and resistant strains. Adsorption assays revealed that virus affinity to the cell surface is a key determinant of infectivity. Saturation of infection occurred at a multiplicity of infection (MOI) of 8 viruses per host and resulted in ∼90–95% of infected cells, with burst sizes ranging from 164 to 191. Insight from the AaV genome implicates recycling of host nucleotides rather than de novo synthesis as a constraint on viral replication. Viral yields and mean burst sizes were significantly diminished with increasing MOI. This phenomenon, which was reminiscent of phage-induced ‘lysis from without’, appeared to be caused by viral contact and was unrelated to bacteria, signaling/toxic compounds, or defective interfering viruses. We posit that high-MOI effects attenuate viral proliferation in natural systems providing a negative feedback on virus-induced bloom collapse.

  2. 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)

  3. Effect of low dose rate irradiation on doped silica core optical fibers

    International Nuclear Information System (INIS)

    Friebele, E.J.; Askins, C.G.; Gingerich, M.E.

    1984-01-01

    The optical attenuation induced in multimode doped silica core optical fiber waveguides by a year's exposure to low dose rate (1 rad/day) ionizing radiation was studied, allowing a characterization of fibers deployed in these environments and a determination of the permanent induced loss in the waveguides. Variations in the induced attenuation at 0.85 μm have been observed with changes in the dose rate between 1 rad/day and 9000 rads/min. These dose rate dependences have been found to derive directly from the recovery that occurs during the exposure; the recovery data predict little or no dose rate dependence of the damage at 1.3 μm. The low dose rate exposure has been found to induce significant permanent attenuation in the 0.7-1.7-μm spectral region in all fibers containing P in the core, whether doped uniformly across the diameter or constrained to a narrow spike on the centerline. Whereas permanent loss was induced at 0.85 μm in a P-free binary Ge-doped silica core fiber by the year's exposure, virtually no damage was observed at 1.3 μm

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

    International Nuclear Information System (INIS)

    Nomura, Takaharu

    2008-01-01

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

  5. 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. Algorithm of pulmonary emphysema extraction using low dose thoracic 3D CT images

    Science.gov (United States)

    Saita, S.; Kubo, M.; Kawata, Y.; Niki, N.; Nakano, Y.; Omatsu, H.; Tominaga, K.; Eguchi, K.; Moriyama, N.

    2006-03-01

    Recently, due to aging and smoking, emphysema patients are increasing. The restoration of alveolus which was destroyed by emphysema is not possible, thus early detection of emphysema is desired. We describe a quantitative algorithm for extracting emphysematous lesions and quantitatively evaluate their distribution patterns using low dose thoracic 3-D CT images. The algorithm identified lung anatomies, and extracted low attenuation area (LAA) as emphysematous lesion candidates. Applying the algorithm to 100 thoracic 3-D CT images and then by follow-up 3-D CT images, we demonstrate its potential effectiveness to assist radiologists and physicians to quantitatively evaluate the emphysematous lesions distribution and their evolution in time interval changes.

  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. 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.

  9. 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

  10. Astragaloside IV attenuates experimental autoimmune encephalomyelitis of mice by counteracting oxidative stress at multiple levels.

    Directory of Open Access Journals (Sweden)

    Yixin He

    Full Text Available Multiple sclerosis (MS is a chronic autoimmune neuroinflammatory disease found mostly in young adults in the western world. Oxidative stress induced neuronal apoptosis plays an important role in the pathogenesis of MS. In current study, astragaloside IV (ASI, a natural saponin molecule isolated from Astragalus membranceus, given at 20 mg/kg daily attenuated the severity of experimental autoimmune encephalomyelitis (EAE in mice significantly. Further studies disclosed that ASI treatment inhibited the increase of ROS and pro-inflammatory cytokine levels, down-regulation of SOD and GSH-Px activities, and elevation of iNOS, p53 and phosphorylated tau in central nervous system (CNS as well as the leakage of BBB of EAE mice. Meanwhile, the decreased ratio of Bcl-2/Bax was reversed by ASI. Moreover, ASI regulated T-cell differentiation and infiltration into CNS. In neuroblast SH-SY5Y cells, ASI dose-dependently reduced cellular ROS level and phosphorylation of tau in response to hydrogen peroxide challenge by modulation of Bcl-2/Bax ratio. ASI also inhibited activation of microglia both in vivo and in vitro. iNOS up-regulation induced by IFNγ stimulation was abolished by ASI dose-dependently in BV-2 cells. In summary, ASI prevented the severity of EAE progression possibly by counterbalancing oxidative stress and its effects via reduction of cellular ROS level, enhancement of antioxidant defense system, increase of anti-apoptotic and anti-inflammatory pathways, as well as modulation of T-cell differentiation and infiltration into CNS. The study suggested ASI may be effective for clinical therapy/prevention of MS.

  11. Astragaloside IV attenuates experimental autoimmune encephalomyelitis of mice by counteracting oxidative stress at multiple levels.

    Science.gov (United States)

    He, Yixin; Du, Min; Gao, Yan; Liu, Hongshuai; Wang, Hongwei; Wu, Xiaojun; Wang, Zhengtao

    2013-01-01

    Multiple sclerosis (MS) is a chronic autoimmune neuroinflammatory disease found mostly in young adults in the western world. Oxidative stress induced neuronal apoptosis plays an important role in the pathogenesis of MS. In current study, astragaloside IV (ASI), a natural saponin molecule isolated from Astragalus membranceus, given at 20 mg/kg daily attenuated the severity of experimental autoimmune encephalomyelitis (EAE) in mice significantly. Further studies disclosed that ASI treatment inhibited the increase of ROS and pro-inflammatory cytokine levels, down-regulation of SOD and GSH-Px activities, and elevation of iNOS, p53 and phosphorylated tau in central nervous system (CNS) as well as the leakage of BBB of EAE mice. Meanwhile, the decreased ratio of Bcl-2/Bax was reversed by ASI. Moreover, ASI regulated T-cell differentiation and infiltration into CNS. In neuroblast SH-SY5Y cells, ASI dose-dependently reduced cellular ROS level and phosphorylation of tau in response to hydrogen peroxide challenge by modulation of Bcl-2/Bax ratio. ASI also inhibited activation of microglia both in vivo and in vitro. iNOS up-regulation induced by IFNγ stimulation was abolished by ASI dose-dependently in BV-2 cells. In summary, ASI prevented the severity of EAE progression possibly by counterbalancing oxidative stress and its effects via reduction of cellular ROS level, enhancement of antioxidant defense system, increase of anti-apoptotic and anti-inflammatory pathways, as well as modulation of T-cell differentiation and infiltration into CNS. The study suggested ASI may be effective for clinical therapy/prevention of MS.

  12. 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.

  13. 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)

  14. 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

  15. 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

  16. 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)

  17. 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.

  18. 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)

  19. 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

  20. 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)

  1. 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.

  2. 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

  3. 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)

  4. Seventy kilovolt ultra-low dose CT of the paranasal sinus: first clinical results

    International Nuclear Information System (INIS)

    Bodelle, B.; Wichmann, J.L.; Klotz, N.; Lehnert, T.; Vogl, T.J.; Luboldt, W.; Schulz, B.

    2015-01-01

    Aim: To evaluate the diagnostic image quality and radiation dose of low-dose 70 kV computed tomography (CT) of the paranasal sinus in comparison to 100 and 120 kV CT. Materials and methods: CT of the paranasal sinus was performed in 127 patients divided into three groups using different tube voltages and currents (70 kV/75 mAs, ultra-low dose protocol, n = 44; 100 kV/40 mAs, standard low-dose protocol, n = 42; 120 kV/40 mAs, standard protocol, n = 41). CT dose index (CTDIvol), dose–length product (DLP), attenuation, image noise and signal-to-noise ratio (SNR) were compared between the groups using Wilcoxon–Mann–Whitney U-test. Subjective diagnostic image quality was compared by using a five-point scale (1 = non-diagnostic, 5 = excellent, read by two readers in consensus) and Cohen's weighted kappa analysis for interobserver agreement. Results: Radiation dose was significantly lower with 70 kV acquisition than 100 and 120 kV (DLP: 31 versus 52 versus 82 mGy·cm; CTDI 2.33 versus 3.95 versus 6.31 mGy, all p < 0.05). Mean SNR (70 kV: 0.37; 100 kV: 0.21; 120 kV: 0.13; p < 0.05) and organ attenuation increased significantly with lower voltages. All examinations showed diagnostic image quality. Subjective diagnostic image quality was higher with standard protocols than the 70 kV protocol (120 kV: 5.0; 100 kV: 4.5; 70 kV: 3.5, p < 0.05) without significant differences with substantial interobserver agreement (κ > 0.59). Conclusion: The ultra-low dose (70 kV) CT imaging of the paranasal sinus allowed for significant dose reduction by 61% and an increased attenuation of organ structures in comparison to standard acquisition while maintaining diagnostic image quality with a slight reduction in subjective image quality. -- Highlights: •Image quality and radiation dose of 70 kV ultra-low dose CT of the paranasal sinus. •70 kV ultra-low dose CT of the paranasal sinus allows for dose reduction by 61%. •70 kV CT of the

  5. The Combination Very Low-Dose Naltrexone–Clonidine in the Management of Opioid Withdrawal

    Science.gov (United States)

    Mannelli, Paolo; Peindl, Kathleen; Wu, Li-Tzy; Patkar, Ashwin A.; Gorelick, David A.

    2013-01-01

    Background The management of withdrawal absorbs substantial clinical efforts in opioid dependence (OD). The real challenge lies in improving current pharmacotherapies. Although widely used, clonidine causes problematic adverse effects and does not alleviate important symptoms of opioid withdrawal, alone or in combination with the opioid antagonist naltrexone. Very low-dose naltrexone (VLNTX) has been shown to attenuate withdrawal intensity and noradrenaline release following opioid agonist taper, suggesting a combination with clonidine may result in improved safety and efficacy. Objectives We investigated the effects of a VLNTX–clonidine combination in a secondary analysis of data from a double-blind, randomized opioid detoxification trial. Methods Withdrawal symptoms and treatment completion were compared following VLNTX (.125 or .25 mg/day) and clonidine (.1–.2 mg q6h) in 127 individuals with OD undergoing 6-day methadone inpatient taper at a community program. Results VLNTX was more effective than placebo or clonidine in reducing symptoms and signs of withdrawal. The use of VLNTX in combination with clonidine was associated with attenuated subjective withdrawal compared with each medication alone, favoring detoxification completion in comparison with clonidine or naltrexone placebo. VLNTX/clonidine was effective in reducing symptoms that are both undertreated and well controlled with clonidine treatment and was not associated with significant adverse events compared with other treatments. Conclusions and Scientific Significance Preliminary results elucidate neurobiological mechanisms of OD and support the utility of controlled studies on a novel VLNTX + low-dose clonidine combination for the management of opioid withdrawal. PMID:22233189

  6. 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

  7. 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 ...

  8. 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...

  9. 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

  10. 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

  11. 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.)

  12. 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...

  13. 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.

  14. 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

  15. 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)

  16. 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

  17. 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

  18. 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)

  19. Radiation retinopathy caused by low dose irradiation and antithyroid drug-induced systemic vasculitis

    International Nuclear Information System (INIS)

    Sonoda, Koh-hei; Ishibashi, Tatsuro

    2005-01-01

    We report on a patient with Graves' disease with radiation retinopathy caused by low-dose irradiation and antithyroid drug-induced antineutrophil cytoplasmic antibody (ANCA)-positive vasculitis. A 38-year-old woman with Graves' disease presented with bilateral blurred vision, micro-aneurysms, telangiectasia, and macular edema. The patient was examined by ophthalmoscopy and fluorescein angiography, and radiation retinopathy was diagnosed. The patient had been treated with low-dose irradiation for her Graves' ophthalmopathy a few years earlier. She also had ANCA-positive vasculitis induced by the antithyroid drug (propylthiouracil, PTU) that had been prescribed for her at that time. Because of multiple avascular areas on both retinas, she was treated by intensive retinal photocoagulation to control progressive retinopathy. The radiation doses used to treat Graves' disease ophthalmopathy are low. Nevertheless, there is still a risk of radiation retinopathy developing in patients with PTU-induced ANCA-positive vasculitis. (author)

  20. 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)

  1. 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

  2. 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.

  3. PPARα inhibition modulates multiple reprogrammed metabolic pathways in kidney cancer and attenuates tumor growth.

    Science.gov (United States)

    Abu Aboud, Omran; Donohoe, Dallas; Bultman, Scott; Fitch, Mark; Riiff, Tim; Hellerstein, Marc; Weiss, Robert H

    2015-06-01

    Kidney cancer [renal cell carcinoma (RCC)] is the sixth-most-common cancer in the United States, and its incidence is increasing. The current progression-free survival for patients with advanced RCC rarely extends beyond 1-2 yr due to the development of therapeutic resistance. We previously identified peroxisome proliferator-activating receptor-α (PPARα) as a potential therapeutic target for this disease and showed that a specific PPARα antagonist, GW6471, induced apoptosis and cell cycle arrest at G0/G1 in RCC cell lines associated with attenuation of cell cycle regulatory proteins. We now extend that work and show that PPARα inhibition attenuates components of RCC metabolic reprogramming, capitalizing on the Warburg effect. The specific PPARα inhibitor GW6471, as well as a siRNA specific to PPARα, attenuates the enhanced fatty acid oxidation and oxidative phosphorylation associated with glycolysis inhibition, and PPARα antagonism also blocks the enhanced glycolysis that has been observed in RCC cells; this effect did not occur in normal human kidney epithelial cells. Such cell type-specific inhibition of glycolysis corresponds with changes in protein levels of the oncogene c-Myc and has promising clinical implications. Furthermore, we show that treatment with GW6471 results in RCC tumor growth attenuation in a xenograft mouse model, with minimal obvious toxicity, a finding associated with the expected on-target effects on c-Myc. These studies demonstrate that several pivotal cancer-relevant metabolic pathways are inhibited by PPARα antagonism. Our data support the concept that targeting PPARα, with or without concurrent inhibition of glycolysis, is a potential novel and effective therapeutic approach for RCC that targets metabolic reprogramming in this tumor.

  4. 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

  5. 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

  6. 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.

  7. 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)

  8. 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)

  9. 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)

  10. 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)

  11. 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.

  12. 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)

  13. 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)

  14. 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

  15. 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.)

  16. 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)

  17. 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.

  18. 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.)

  19. 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)

  20. 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

  1. 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)

  2. 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.

  3. 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 (

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

    Energy Technology Data Exchange (ETDEWEB)

    Kroeger, Kai; Elsayad, Khaled; Moustakis, Christos; Haverkamp, Uwe; Eich, Hans Theodor [University Hospital of Muenster, Department of Radiation Oncology, Muenster (Germany)

    2017-12-15

    Low-dose total skin electron beam therapy (TSEBT) is attracting increased interest for the effective palliative treatment of primary cutaneous T-cell lymphoma (pCTCL). In this study, we compared toxicity profiles following various radiation doses. We reviewed the records of 60 patients who underwent TSEBT for pCTCL between 2000 and 2016 at the University Hospital of Munster. The treatment characteristics of the radiotherapy (RT) regimens and adverse events (AEs) were then analyzed and compared. In total, 67 courses of TSEBT were administered to 60 patients. Of these patients, 34 (51%) received a standard dose with a median surface dose of 30 Gy and 33 patients (49%) received a low dose with the median surface dose of 12 Gy (7 salvage low-dose TSEBT courses were administered to 5 patients). After a median follow-up of 15 months, the overall AE rate was 100%, including 38 patients (57%) with grade 2 and 7 (10%) with grade 3 AEs. Patients treated with low-dose TSEBT had significantly fewer grade 2 AEs than those with conventional dose regimens (33 vs. 79%, P < 0.001). A lower grade 3 AE rate was also observed in patients who had received the low-dose regimen compared to those with the conventional dose regimens (6 vs. 15%, P = 0.78). Multiple/salvage low-dose TSEBT courses were not associated with an increased risk of acute AEs. Low-dose TSEBT regimens are associated with significantly fewer grade 2 acute toxicities compared with conventional doses of TSEBT. Repeated/Salvage low-dose TSEBT, however, appears to be tolerable and can even be applied safely in patients with cutaneous relapses. (orig.) [German] Eine niedrigdosierte Ganzhautelektronenbestrahlung (TSEBT) wird vermehrt zur effektiven palliativen Behandlung von Patienten mit primaer kutanen T-Zell-Lymphomen (pCTCL) eingesetzt. In dieser Studie vergleichen wir die Toxizitaetsprofile verschiedener Dosiskonzepte. Untersucht wurden 60 zwischen 2000 und 2016 am Universitaetsklinikum Muenster mittels TSEBT

  5. 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)

  6. 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)

  7. 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

  8. 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.

  9. 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

  10. 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

  11. 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)

  12. 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.

  13. Learning from agriculture: understanding low-dose antimicrobials as drivers of resistome expansion

    Directory of Open Access Journals (Sweden)

    Yaqi eYou

    2014-06-01

    Full Text Available Antimicrobial resistance is a growing public health challenge worldwide, with agricultural use of antimicrobials being one major contributor to the emergence and dissemination of antimicrobial resistance. Globally, most antimicrobials are used in industrial food animal production, a major context for microbiomes encountering low-doses or subtherapeutic-levels of antimicrobial agents from all mechanistic classes. This modern practice exerts broad eco-evolutionary effects on the gut microbiome of food animals, which is subsequently transferred to animal waste. This waste contains complex constituents that are challenging to treat, including antimicrobial resistance determinants and low-dose antimicrobials. Unconfined storage or land deposition of a large volume of animal waste causes its wide contact with the environment and drives the expansion of the environmental resistome through mobilome facilitated horizontal genet transfer. The expanded environmental resistome, which encompasses both natural constituents and anthropogenic inputs, can persist under multiple stressors from agriculture and may re-enter humans, thus posing a public health risk to humans. For these reasons, this review focuses on agricultural antimicrobial use as a laboratory for understanding low-dose antimicrobials as drivers of resistome expansion, briefly summarizes current knowledge on this topic, highlights the importance of research specifically on environmental microbial ecosystems considering antimicrobial resistance as environmental pollution, and calls attention to the needs for longitudinal studies at the systems level.

  14. Learning from agriculture: understanding low-dose antimicrobials as drivers of resistome expansion.

    Science.gov (United States)

    You, Yaqi; Silbergeld, Ellen K

    2014-01-01

    Antimicrobial resistance is a growing public health challenge worldwide, with agricultural use of antimicrobials being one major contributor to the emergence and dissemination of antimicrobial resistance (AMR). Globally, most antimicrobials are used in industrial food animal production, a major context for microbiomes encountering low-doses or subtherapeutic-levels of antimicrobial agents from all mechanistic classes. This modern practice exerts broad eco-evolutionary effects on the gut microbiome of food animals, which is subsequently transferred to animal waste. This waste contains complex constituents that are challenging to treat, including AMR determinants and low-dose antimicrobials. Unconfined storage or land deposition of a large volume of animal waste causes its wide contact with the environment and drives the expansion of the environmental resistome through mobilome facilitated horizontal genet transfer. The expanded environmental resistome, which encompasses both natural constituents and anthropogenic inputs, can persist under multiple stressors from agriculture and may re-enter humans, thus posing a public health risk to humans. For these reasons, this review focuses on agricultural antimicrobial use as a laboratory for understanding low-dose antimicrobials as drivers of resistome expansion, briefly summarizes current knowledge on this topic, highlights the importance of research specifically on environmental microbial ecosystems considering AMR as environmental pollution, and calls attention to the needs for longitudinal studies at the systems level.

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

    Energy Technology Data Exchange (ETDEWEB)

    Bedford, Joel

    2014-04-18

    activity) were examined after exposure of synchronized G1 cells to 137Cs c rays. DNA-PKcs mutant cells defective in phosphorylation at multiple sites withinthe T2609 cluster or within the PI3K domain displayed extreme radiosensitivity. Cells defective at the S2056 cluster or T2609 single site alone were only mildly radiosensitive, but cells defective at even one site in both the S2056 and T2609 clusters were maximally radiosensitive. Thus a synergism between the capacity for phosphorylation at the S2056 and T2609 clusterswas found to be critical for induction of radiosensitivity.

  16. Lateral topography for reducing effective dose in low-dose chest CT.

    Science.gov (United States)

    Bang, Dong-Ho; Lim, Daekeon; Hwang, Wi-Sub; Park, Seong-Hoon; Jeong, Ok-man; Kang, Kyung Wook; Kang, Hohyung

    2013-06-01

    The purposes of this study were to assess radiation exposure during low-dose chest CT by using lateral topography and to compare the lateral topographic findings with findings obtained with anteroposterior topography alone and anteroposterior and lateral topography combined. From November 2011 to February 2012, 210 male subjects were enrolled in the study. Age, weight, and height of the men were recorded. All subjects were placed into one of three subgroups based on the type of topographic image obtained: anteroposterior topography, lateral topography, and both anteroposterior and lateral topography. Imaging was performed with a 128-MDCT scanner. CT, except for topography, was the same for all subjects. A radiologist analyzed each image, recorded scan length, checked for any insufficiencies in the FOV, and calculated the effective radiation dose. One-way analysis of variance and multiple comparisons were used to compare the effective radiation exposure and scan length between groups. The mean scan length in the anteroposterior topography group was significantly greater than that of the lateral topography group and the combined anteroposterior and lateral topography group (p topography group (0.735 ± 0.033 mSv) was significantly lower than that for the anteroposterior topography group (0.763 ± 0.038 mSv) and the combined anteroposterior and lateral topography group (0.773 ± 0.038) (p < 0.001). Lateral topographic low-dose CT was associated with a lower effective radiation dose and scan length than either anteroposterior topographic low-dose chest CT or low-dose chest CT with both anteroposterior and lateral topograms.

  17. 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

  18. Consequences of low dose ionizing radiation exposure on the hippocampal microenvironment.

    Directory of Open Access Journals (Sweden)

    Munjal M Acharya

    Full Text Available The response of the brain to irradiation is complex, involving a multitude of stress inducible pathways that regulate neurotransmission within a dynamic microenvironment. While significant past work has detailed the consequences of CNS radiotherapy following relatively high doses (≥ 45 Gy, few studies have been conducted at much lower doses (≤ 2 Gy, where the response of the CNS (like many other tissues may differ substantially from that expected from linear extrapolations of high dose data. Low dose exposure could elicit radioadaptive modulation of critical CNS processes such as neurogenesis, that provide cellular input into hippocampal circuits known to impact learning and memory. Here we show that mice deficient for chemokine signaling through genetic disruption of the CCR2 receptor exhibit a neuroprotective phenotype. Compared to wild type (WT animals, CCR2 deficiency spared reductions in hippocampal neural progenitor cell survival and stabilized neurogenesis following exposure to low dose irradiation. While radiation-induced changes in microglia levels were not found in WT or CCR2 deficient animals, the number of Iba1+ cells did differ between each genotype at the higher dosing paradigms, suggesting that blockade of this signaling axis could moderate the neuroinflammatory response. Interestingly, changes in proinflammatory gene expression were limited in WT animals, while irradiation caused significant elevations in these markers that were attenuated significantly after radioadaptive dosing paradigms in CCR2 deficient mice. These data point to the importance of chemokine signaling under low dose paradigms, findings of potential significance to those exposed to ionizing radiation under a variety of occupational and/or medical scenarios.

  19. 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

  20. Data matching for free-surface multiple attenuation by multidimensional deconvolution

    Science.gov (United States)

    van der Neut, Joost; Frijlink, Martijn; van Borselen, Roald

    2012-09-01

    A common strategy for surface-related multiple elimination of seismic data is to predict multiples by a convolutional model and subtract these adaptively from the input gathers. Problems can be posed by interfering multiples and primaries. Removing multiples by multidimensional deconvolution (MDD) (inversion) does not suffer from these problems. However, this approach requires data to be consistent, which is often not the case, especially not at interpolated near-offsets. A novel method is proposed to improve data consistency prior to inversion. This is done by backpropagating first-order multiples with a time-gated reference primary event and matching these with early primaries in the input gather. After data matching, multiple elimination by MDD can be applied with a deterministic inversion scheme.

  1. Low dose of donepezil improves gabapentin analgesia in the rat spared nerve injury model of neuropathic pain

    DEFF Research Database (Denmark)

    Folkesson, Anna; Honoré, Per Hartvig; Andersen, Lene Munkholm

    2010-01-01

    the effect of the cholinesterase inhibitor donepezil when administered (1) alone and (2) as low-dose in combination with the first-line recommendation gabapentin. The co-administration studies were performed following single and multiple dosing. Single, parenteral dosing of donepezil (1, 1.5 and 3 mg...

  2. 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.

  3. Low-dose acute vanillin is beneficial against harmaline-induced tremors in rats.

    Science.gov (United States)

    Abdulrahman, Al Asmari; Faisal, Kunnathodi; Meshref, Ali Al Amri; Arshaduddin, Mohammed

    2017-03-01

    To study the effect of pretreatment with low doses of vanillin, a flavoring agent used as a food additive, on harmaline-induced tremor in rats. Sprague Dawley rats (110 ± 5 g) were divided into groups of six animals each. Vanillin (6.25 mg, 12.5 mg, and 25 mg/kg) was administered by gavage to different groups of rats, 30 minutes before the induction of tremor. Harmaline (10 mg/kg, i.p.) was used for the induction of tremor. The latency of onset, duration, tremor intensity, tremor index, and spontaneous locomotor activity were recorded. A separate batch of animals was used for the determination of serotonin (5HT) and 5 hydroxyindole acetic acid (5HIAA) levels in the brain. Harmaline treatment resulted in characteristic tremor that lasted for more than 2 hours and decreased the locomotor activity of rats. Pre-treatment with vanillin significantly reduced the duration, intensity, and tremor index of harmaline-treated animals. Vanillin treatment also significantly attenuated harmaline-induced decrease in the locomotor activity. An increase in 5HT levels and the changes in 5HIAA/5HT ratio observed in harmaline treated rats were significantly corrected in vanillin pretreated animals. Vanillin in low doses reduces harmaline-induced tremor in rats, probably through its modulating effect on serotonin levels in the brain. These findings suggest a beneficial effect of vanillin in essential tremor.

  4. Usefulness of low dose oral contrast media in 18F-FDG PET/CT

    International Nuclear Information System (INIS)

    An, Young Sil; Yoon, Joon Kee; Hong, Seon Pyo; Joh, Chul Woo; Yoon, Seok Nam

    2006-01-01

    The standard protocol using large volume of oral contrast media may cause gastrointestinal discomfort and contrast-related artifacts in PET/CT. The aim of this study was to evaluate the usefulness of low dose oral contrast in 18 F-FDG PET/CT. We retrospectively reviewed the whole-body PET/CT images in a total of 435 patients. About 200 ml of oral contrast agent (barium sulfate) was administered immediately before injection of 18 F-FDG. The FDG uptake of intestines was analyzed by visual and semi-quantitative method on transaxial, coronal and saggital planes. Seventy (16%, 113 sites) of 435 images showed high FDG uptake (peak SUV > 4); 50 (74%, 84 sites) with diffuse and 20 (26%, 29 sites) with focal uptake. The most commonly delivered site of oral contrast media was small bowel (n = 27, 39%). On PET/CT images, FDG uptake coexisted with oral contrast media in 26 patients (54%, 38 sites) with diffuse pattern and 9 (45%, 9 sites) with focal pattern, and by sites, those were 38 (45%) and 9 (31%), respectively. In small bowel regions, the proportion of coexistence reached as high as 61% (29/47 sites). A visual analysis of available non-attenuation corrected PET images of 27 matched regions revealed no contrast-related artifact. We concluded that the application of low dose contrast media could be helpful in the evaluation of abdominal uptake in the FDG PET/CT image

  5. Usefulness of low dose oral contrast media in FDG PET/CT

    Energy Technology Data Exchange (ETDEWEB)

    An, Y. S.; Yun, J. G.; Lee, M. H.; Cho, C. W.; Yun, S. N [Ajou University Medical Center, Suwon (Korea, Republic of)

    2004-07-01

    Oral contrast media might help in interpreting PET/CT images, allowing better discrimination between physiologic and pathologic abdominal uptake. The aim of this study was to evaluate the usefulness of low dose oral contrast on FDG PET/CT. A total of 435 cancer patients received 200mL of oral Barium with water(200mL) immediately before FDG injection. PET images were reconstructed using attenuation correction and iterative reconstruction. The FDG uptake in gastrointestinal(GI) tract were analyzed by visual and semiquantitative method in transaxial, coronal and sagittal planes. Seventy patients(16%, 113 sites) of 435 images showed high FDG uptake(pSUV>4.0) : 50(74%, 84 sites) with diffuse uptake and 20(26%, 29sites) with focal uptake. The most common distribution site of oral contrast media was small bowel (n=27, 39%) and others were small bowel with transverse colon(n=6, 8%), small bowel with ascending and sigmoid colon(n=6, 8%) and etc. In PET/CT images, FDG uptake coexisted with oral contrast was showed in 26 patients(54%) with diffuse pattern and 9(45%) with focal pattern, and by sites, those were 38(45%) and 9(31%), respectively. In small bowel regions, the most common distribution site, the proportion of coexistence reached as high as 61% (29 in the total 47 sites). Application of low dose contrast agent can be helpful in the evaluation of intestinal uptake in FDG PET/CT image.

  6. Usefulness of low dose oral contrast media in FDG PET/CT

    International Nuclear Information System (INIS)

    An, Y. S.; Yun, J. G.; Lee, M. H.; Cho, C. W.; Yun, S. N

    2004-01-01

    Oral contrast media might help in interpreting PET/CT images, allowing better discrimination between physiologic and pathologic abdominal uptake. The aim of this study was to evaluate the usefulness of low dose oral contrast on FDG PET/CT. A total of 435 cancer patients received 200mL of oral Barium with water(200mL) immediately before FDG injection. PET images were reconstructed using attenuation correction and iterative reconstruction. The FDG uptake in gastrointestinal(GI) tract were analyzed by visual and semiquantitative method in transaxial, coronal and sagittal planes. Seventy patients(16%, 113 sites) of 435 images showed high FDG uptake(pSUV>4.0) : 50(74%, 84 sites) with diffuse uptake and 20(26%, 29sites) with focal uptake. The most common distribution site of oral contrast media was small bowel (n=27, 39%) and others were small bowel with transverse colon(n=6, 8%), small bowel with ascending and sigmoid colon(n=6, 8%) and etc. In PET/CT images, FDG uptake coexisted with oral contrast was showed in 26 patients(54%) with diffuse pattern and 9(45%) with focal pattern, and by sites, those were 38(45%) and 9(31%), respectively. In small bowel regions, the most common distribution site, the proportion of coexistence reached as high as 61% (29 in the total 47 sites). Application of low dose contrast agent can be helpful in the evaluation of intestinal uptake in FDG PET/CT image

  7. Prophylactic low-dose aspirin is effective antithrombotic therapy for combination treatments of thalidomide or lenalidomide in myeloma.

    Science.gov (United States)

    Niesvizky, Ruben; Martínez-Baños, Déborah; Jalbrzikowski, Jessica; Christos, Paul; Furst, Jessica; De Sancho, Maria; Mark, Tomer; Pearse, Roger; Mazumdar, Madhu; Zafar, Faiza; Pekle, Karen; Leonard, John; Jayabalan, David; Coleman, Morton

    2007-12-01

    Multiple myeloma (MM) patients have a propensity for thromboembolic events (TE), and treatment with thalidomide/dexamethasone or lenalidomide/dexamethasone increases this risk. This report describes the use of low-dose aspirin (81 mg) as primary thromboprophylaxis in three series of MM patients receiving thalidomide or lenalidomide with other drugs. In the first regimen (clarithromycin, thalidomide, dexamethasone), initiation of low-dose aspirin negated the occurrence of any further TE. In a second study, prophylactic aspirin given with thalidomide/dexamethasone resulted in a rate of TE similar to that seen with dexamethasone alone (without aspirin). A third study (n = 72) evaluated thrombosis rates with aspirin and a lenalidomide-containing regimen (clarithromycin, lenalidomide, dexamethasone). Of nine occurrences of thromboembolism, five were associated with aspirin interruption or poor compliance. Low-dose aspirin appears to reduce the incidence of thrombosis with these regimens. Routine use of aspirin as antithrombotic prophylaxis in MM patients receiving immunomodulatory drugs with corticosteroids is warranted.

  8. Low-dose phase contrast tomography with conventional x-ray sources

    Energy Technology Data Exchange (ETDEWEB)

    Hagen, C. K., E-mail: charlotte.hagen.10@ucl.ac.uk; Endrizzi, M.; Diemoz, P. C.; Olivo, A. [Department of Medical Physics and Bioengineering, University College London, Malet Place, Gower Street, London WC1E 6BT (United Kingdom); Munro, P. R. T. [Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia and Centre for Microscopy, Characterisation, and Analysis, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009 (Australia)

    2014-07-15

    Purpose: The edge illumination (EI) x-ray phase contrast imaging (XPCi) method has been recently further developed to perform tomographic and, thus, volumetric imaging. In this paper, the first tomographic EI XPCi images acquired with a conventional x-ray source at dose levels below that used for preclinical small animal imaging are presented. Methods: Two test objects, a biological sample and a custom-built phantom, were imaged with a laboratory-based EI XPCi setup in tomography mode. Tomographic maps that show the phase shift and attenuating properties of the object were reconstructed, and analyzed in terms of signal-to-noise ratio and quantitative accuracy. Dose measurements using thermoluminescence devices were performed. Results: The obtained images demonstrate that phase based imaging methods can provide superior results compared to attenuation based modalities for weakly attenuating samples also in 3D. Moreover, and, most importantly, they demonstrate the feasibility of low-dose imaging. In addition, the experimental results can be considered quantitative within the constraints imposed by polychromaticity. Conclusions: The results, together with the method's dose efficiency and compatibility with conventional x-ray sources, indicate that tomographic EI XPCi can become an important tool for the routine imaging of biomedical samples.

  9. Low-Dose Radiation Activates Akt and Nrf2 in the Kidney of Diabetic Mice: A Potential Mechanism to Prevent Diabetic Nephropathy

    Directory of Open Access Journals (Sweden)

    Xiao Xing

    2012-01-01

    Full Text Available Repetitive exposure of diabetic mice to low-dose radiation (LDR at 25 mGy could significantly attenuate diabetes-induced renal inflammation, oxidative damage, remodeling, and dysfunction, for which, however, the underlying mechanism remained unknown. The present study explored the effects of LDR on the expression and function of Akt and Nrf2 in the kidney of diabetic mice. C57BL/6J mice were used to induce type 1 diabetes with multiple low-dose streptozotocin. Diabetic and age-matched control mice were irradiated with whole body X-rays at either single 25 mGy and 75 mGy or accumulated 75 mGy (25 mGy daily for 3 days and then sacrificed at 1–12 h for examining renal Akt phosphorylation and Nrf2 expression and function. We found that 75 mGy of X-rays can stimulate Akt signaling pathway and upregulate Nrf2 expression and function in diabetic kidneys; single exposure of 25 mGy did not, but three exposures to 25 mGy of X-rays could offer a similar effect as single exposure to 75 mGy on the stimulation of Akt phosphorylation and the upregulation of Nrf2 expression and transcription function. These results suggest that single 75 mGy or multiple 25 mGy of X-rays can stimulate Akt phosphorylation and upregulate Nrf2 expression and function, which may explain the prevention of LDR against the diabetic nephropathy mentioned above.

  10. Consequences of the exposure at low dose rates-contribution of animal experimentation

    International Nuclear Information System (INIS)

    Masse, R.

    1990-01-01

    The exposure of laboratory animals to the various types of radiations will induce cancers in relation with the tissue absorbed doses. The shape of the dose-effet relationship is most variable. It is important to distinguish which tumours are comparable to human tumours. Those showing more analogies answer but seldom to the classical lineo-quadratic relationship; however, a strong attenuation of induction is demonstrated at low dose rates. Quasi-threshold relationships are seen after the exposure of some tissues to high-LET radiations. These observations question the validity of generalizing the radiobiologists' dual action theory, setting the origin of the dose-effect relationship in the induction of events within the DNA molecule. There is an alternative in the cellular collaboration events; it assumes that the effectiveness per dose unit decreases constantly as an inverse function of the dose rate [fr

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

    Directory of Open Access Journals (Sweden)

    S Peivandi

    2010-03-01

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

  12. 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.)

  13. 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.)

  14. 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.

  15. 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

  16. 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.

  17. 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

  18. 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

  19. 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

  20. 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)

  1. 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

  2. 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)

  3. 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

  4. 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

  5. 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.

  6. A review of the bystander effect and its implications for low-dose exposure

    International Nuclear Information System (INIS)

    Prise, K.M.; Folkard, M.; Michael, B.D.

    2003-01-01

    Current models for the interaction between ionising radiation and living cells or tissues are based on direct genetic damage produced by energy deposition in cellular DNA. An important observation which has questioned this basic assumption is radiation-induced bystander response, in which cells which have not been directly targeted respond if their neighbours have been exposed. This response predominates at low doses of relevance to radiation risk analysis (<0.2 Gy) and therefore needs to be fully characterised. The development of microbeams, which allow individual cells within populations to be targeted with precise doses of radiation, has provided a useful tool for quantifying this response. The authors' studies have targeted individual human and mouse cells with counted protons and helium ions and monitored neighbouring cells for the production of bystander responses. Bystander responses have been measured after exposures as low as a single proton or helium ion delivered to an individual cell. An important aspect is that these responses saturate with increasing dose to the single target cell, thus the relative roles of direct and indirect (non-targeted) responses change with dose. Studies with multicellular, tissue-based models are providing evidence that bystander responses may have a complex phenotype involving multiple pathways and the overall response may be a balance between multiple signalling processes and responses to radiation exposure. Current models for radiation risk assume a linear non-threshold response and have generally been extrapolated from high-dose exposures. The involvement of competing processes at low doses may have important consequences for understanding the effects of low-dose exposure. (author)

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

    International Nuclear Information System (INIS)

    Ouchi, Noriyuki B.

    2003-01-01

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

  8. Low-dose aripiprazole for refractory burning mouth syndrome

    Directory of Open Access Journals (Sweden)

    Umezaki Y

    2016-05-01

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

  9. Low doses of neutrons induce changes in gene expression

    International Nuclear Information System (INIS)

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

    1993-01-01

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

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

    International Nuclear Information System (INIS)

    Prakash, Rajeev

    1999-01-01

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

  11. Development of microcontroller based instrumentation for low dose implantation

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  12. Treatment with Fenofibrate plus a low dose of Benznidazole attenuates cardiac dysfunction in experimental Chagas disease

    Directory of Open Access Journals (Sweden)

    Ágata C. Cevey

    2017-12-01

    Full Text Available Trypanosoma cruzi induces serious cardiac alterations during the chronic infection. Intense inflammatory response observed from the beginning of infection, is critical for the control of parasite proliferation and evolution of Chagas disease. Peroxisome proliferator-activated receptors (PPAR-α, are known to modulate inflammation.In this study we investigated whether a PPAR-α agonist, Fenofibrate, improves cardiac function and inflammatory parameters in a murine model of T. cruzi infection. BALB/c mice were sequentially infected with two T. cruzi strains of different genetic background. Benznidazole, commonly used as trypanocidal drug, cleared parasites but did not preclude cardiac pathology, resembling what is found in human chronic chagasic cardiomyopathy. Fenofibrate treatment restored to normal values the ejection and shortening fractions, left ventricular end-diastolic, left ventricular end-systolic diameter, and isovolumic relaxation time. Moreover, it reduced cardiac inflammation and fibrosis, decreased the expression of pro-inflammatory (IL-6, TNF-α and NOS2 and heart remodeling mediators (MMP-9 and CTGF, and reduced serum creatine kinase activity. The fact that Fenofibrate partially inhibited NOS2 expression and NO release in the presence of a PPAR-α non-competitive inhibitor, suggested it also acted through PPAR-α-independent pathways. Since IκBα cytosolic degradation was inhibited by Fenofibrate, it can be concluded that the NFκB pathway has a role in its effects. Thus, we demonstrate that Fenofibrate acts through PPAR-α-dependent and -independent pathways.Our study shows that combined treatment with Fenofibrate plus Benznidazole is able both to reverse the cardiac dysfunction associated with the ongoing inflammatory response and fibrosis and to attain parasite clearance in an experimental model of Chagas disease. Keywords: Trypanosoma cruzi, Heart dysfunction, PPAR-α, Fenofibrate treatment, Inflammatory mediators

  13. Testing the count rate performance of the scintillation camera by exponential attenuation: Decaying source; Multiple filters

    International Nuclear Information System (INIS)

    Adams, R.; Mena, I.

    1988-01-01

    An algorithm and two fortrAN programs have been developed to evaluate the count rate performance of scintillation cameras from count rates reduced exponentially, either by a decaying source or by filtration. The first method is used with short-lived radionuclides such as 191 /sup m/Ir or 191 /sup m/Au. The second implements a National Electrical Manufacturers' Association (NEMA) protocol in which the count rate from a source of 191 /sup m/Tc is attenuated by a varying number of copper filters stacked over it. The count rate at each data point is corrected for deadtime loss after assigning an arbitrary deadtime (tau). A second-order polynomial equation is fitted to the logarithms of net count rate values: ln(R) = A+BT+CT 2 where R is the net corrected count rate (cps), and T is the elapsed time (or the filter thickness in the NEMA method). Depending on C, tau is incremented or decremented iteratively, and the count rate corrections and curve fittings are repeated until C approaches zero, indicating a correct value of the deadtime (tau). The program then plots the measured count rate versus the corrected count rate values

  14. Multiple antigens of Yersinia pestis delivered by live recombinant attenuated Salmonella vaccine strains elicit protective immunity against plague.

    Science.gov (United States)

    Sanapala, Shilpa; Rahav, Hannah; Patel, Hetal; Sun, Wei; Curtiss, Roy

    2016-05-05

    Based on our improved novel Salmonella vaccine delivery platform, we optimized the recombinant attenuated Salmonella typhimurium vaccine (RASV) χ12094 to deliver multiple Yersinia pestis antigens. These included LcrV196 (amino acids, 131-326), Psn encoded on pYA5383 and F1 encoded in the chromosome, their synthesis did not cause adverse effects on bacterial growth. Oral immunization with χ12094(pYA5383) simultaneously stimulated high antibody titers to LcrV, Psn and F1 in mice and presented complete protection against both subcutaneous (s.c.) and intranasal (i.n.) challenges with high lethal doses of Y. pestis CO92. Moreover, no deaths or other disease symptoms were observed in SCID mice orally immunized with χ12094(pYA5383) over a 60-day period. Therefore, the trivalent S. typhimurium-based live vaccine shows promise for a next-generation plague vaccine. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    International Nuclear Information System (INIS)

    1995-01-01

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

  16. The health effects of low-dose ionizing radiation

    International Nuclear Information System (INIS)

    Dixit, A.N.; Dixit, Nishant

    2012-01-01

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

  17. GPR attenuation analyses using spectral ratios of primary and multiple arrivals: examples from Welsh peat bogs

    Science.gov (United States)

    Booth, A.; Carless, D.; Kulessa, B.

    2014-12-01

    Ground penetrating radar (GPR) is widely applied to qualitative and quantitative interpretation of near-surface targets. Surface deployments of GPR most widely characterise physical properties in terms of some measure of GPR wavelet velocity. Wavelet amplitude is less-often considered, potentially due to difficulties in measuring this quantity: amplitudes are distorted by the anisotropic radiation pattern of antennas, and the ringy GPR wavelet can make successive events difficult to isolate. However, amplitude loss attributes could provide a useful means of estimating the physical properties of a target. GPR energy loss is described by the bandwidth-limited quality factor Q* which, for low-loss media, is proportional to the ratio of dielectric permittivity, ɛ, and electrical conductivity, σ. Comparing the frequency content of two arrivals yields an estimate of interval Q*, but only if they are sufficiently distinct. There may be sufficient separation between a primary reflection and its long-path multiple (i.e. a 'repeat path' of the primary reflection) therefore a dataset that is rich in multiples may be suitable for robust Q* analysis. The Q* between a primary and multiple arrival describes all frequency-dependent loss mechanisms in the interval between the free-surface and the multiple-generating horizon: assuming that all reflectivity is frequency-independent, Q* can be used to estimate ɛ and/or σ. We measure Q* according to the spectral ratio method, for synthetic and real GPR datasets. Our simulations are performed using the finite-difference algorithm GprMax, and represent our example data of GPR acquisitions over peat bogs. These data are a series of 100 MHz GPR acquisitions over sites in the Brecon Beacons National Park of South Wales. The base of the bogs (the basal peat/mineral soil contact) is often a strong multiple-generating horizon. As an example, data from Waun Ddu bog show these events lagging by ~75 ns: GPR velocity is measured here at 0

  18. The spectrum of mutation produced by low dose radiation

    International Nuclear Information System (INIS)

    Morley, Alexander A.; Turner, David R.

    2004-01-01

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

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

    International Nuclear Information System (INIS)

    Bojtor, I.; Koeteles, G.J.

    1998-01-01

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

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

    International Nuclear Information System (INIS)

    Souidi, Maamar; Grison, Stephane

    2014-01-01

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

  1. Transcriptome profiling of mice testes following low dose irradiation

    DEFF Research Database (Denmark)

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

    2013-01-01

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

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

    DEFF Research Database (Denmark)

    Engbaek, Mette; Hjerrild, Mette; Hallas, Jesper

    2010-01-01

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

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

    Science.gov (United States)

    Umezaki, Yojiro; Takenoshita, Miho; Toyofuku, Akira

    2016-01-01

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

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

    International Nuclear Information System (INIS)

    Zuur, Ciska

    2002-01-01

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

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

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  6. Low-dose irradiation for controlling prostate cancer

    International Nuclear Information System (INIS)

    Cuttler, J.M.

    2003-01-01

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

  7. Optical fiber sensor for low dose gamma irradiation monitoring

    Science.gov (United States)

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

    2016-05-01

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

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

    International Nuclear Information System (INIS)

    Chen Dong; Liu Jiamei; Chen Aijun; Liu Shuzheng

    1999-01-01

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

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

    International Nuclear Information System (INIS)

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

    2001-01-01

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

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

    International Nuclear Information System (INIS)

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

    2000-01-01

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

  11. Low dose preoperative radiotherapy for carcinoma of the oesophagus

    International Nuclear Information System (INIS)

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

    1992-01-01

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

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

    International Nuclear Information System (INIS)

    Orton, C.G.

    1998-01-01

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

  13. Lung cancer screening with low-dose CT

    International Nuclear Information System (INIS)

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

    2003-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-04-15

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

  15. Varicose Vein Stripping Under Low-Dose Spinal Anaesthesia

    Directory of Open Access Journals (Sweden)

    Nalan Muhammedoğlu

    2014-03-01

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

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

    Directory of Open Access Journals (Sweden)

    Xinhua Yan

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

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

    International Nuclear Information System (INIS)

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

    2009-01-01

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

  18. Emphysema Quantification Using Low Dose Chest CT: Changes in Follow-Up Examinations of Asymptomatic Smokers

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Eun Ho; Sun, Joo Sung; Kang, Doo Kyung [Dept. of Radiology, Ajou University School of Medicine, Suwon (Korea, Republic of); Park, Kwang Joo; Park, Kyung Joo [Dept. of Pulmolary Medicine, Ajou University School of Medicine, Suwon (Korea, Republic of)

    2012-01-15

    To evaluate the changes of emphysema quantification in a follow-up low dose CT compared with pulmonary function test (PFT) results in asymptomatic smokers. We selected 66 asymptomatic smokers (> 40 years old) who underwent a follow-up low dose CT at least one year after the first CT as well as PFT within the same time period. Emphysema quantification was performed using an automated measurement software and an emphysema index (EI) was calculated using multiple threshold values (-970--900 HU). The interval change of EI ({Delta} EI) was compared with the change in the PFT values. Mean follow-up %forced expiratory volume in 1 second (88.1), %forced vital capacity (FVC) (89.5) and forced expiratory flow between 25 and 75% of vital capacity (3.21) were significantly lower compared with the values of initial tests (93.3, 93.1, 3.48). The mean EIs (2.4-25.6%) increased on follow-up CTs compared with initial EIs (2.1-24.5%), though the increase was not statistically significant. In a group with a follow-up period of 2 years or more (n = 32), EI significantly increased when using -900 HU as the threshold. The ({Delta} EIs were poorly correlated with the ({Delta} PFT values, but significantly correlated with ({Delta} FVC (r = -0.32--0.27). Emphysema quantification using low dose CT was not effective for the evaluation of short-term changes in less than a 2-year period, but may be used for long term follow-up series in asymptomatic smokers.

  19. 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

  20. Characterization of MOSFET dosimeters for low-dose measurements in maxillofacial anthropomorphic phantoms.

    Science.gov (United States)

    Koivisto, Juha H; Wolff, Jan E; Kiljunen, Timo; Schulze, Dirk; Kortesniemi, Mika

    2015-07-08

    The aims of this study were to characterize reinforced metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters to assess the measurement uncertainty, single exposure low-dose limit with acceptable accuracy, and the number of exposures required to attain the corresponding limit of the thermoluminescent dosimeters (TLD). The second aim was to characterize MOSFET dosimeter sensitivities for two dental photon energy ranges, dose dependency, dose rate dependency, and accumulated dose dependency. A further aim was to compare the performance of MOSFETs with those of TLDs in an anthropomorphic phantom head using a dentomaxillofacial CBCT device. The uncertainty was assessed by exposing 20 MOSFETs and a Barracuda MPD reference dosimeter. The MOSFET dosimeter sensitivities were evaluated for two photon energy ranges (50-90 kVp) using a constant dose and polymethylmethacrylate backscatter material. MOSFET and TLD comparative point-dose measurements were performed on an anthropomorphic phantom that was exposed with a clinical CBCT protocol. The MOSFET single exposure low dose limit (25% uncertainty, k = 2) was 1.69 mGy. An averaging of eight MOSFET exposures was required to attain the corresponding TLD (0.3 mGy) low-dose limit. The sensitivity was 3.09 ± 0.13 mV/mGy independently of the photon energy used. The MOSFET dosimeters did not present dose or dose rate sensitivity but, however, presented a 1% decrease of sensitivity per 1000 mV for accumulated threshold voltages between 8300 mV and 17500 mV. The point doses in an anthropomorphic phantom ranged for MOSFETs between 0.24 mGy and 2.29 mGy and for TLDs between 0.25 and 2.09 mGy, respectively. The mean difference was -8%. The MOSFET dosimeters presented statistically insignificant energy dependency. By averaging multiple exposures, the MOSFET dosimeters can achieve a TLD-comparable low-dose limit and constitute a feasible method for diagnostic dosimetry using anthropomorphic phantoms. However, for single in

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

    Science.gov (United States)

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

    2017-10-19

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-07-01

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

  3. Pancytopenia after low dose methotrexate therapy in a hemodialysis patient: case report and review of literature.

    Science.gov (United States)

    Yang, Ching-Ping; Kuo, Mei-Chuan; Guh, Jinn-Yuh; Chen, Hung-Chun

    2006-01-01

    Methotrexate (MTX) is widely used in the treatment of rheumatoid arthritis (RA) with a side effect of pancytopenia. However, only a few cases of severe pancytopenia caused by low-dose MTX therapy have been reported, and the condition is rarely reported in uremic patients on dialysis therapy. We thereby report a hemodialysis patient who developed severe pancytopenia after oral treatment with low-dose MTX for RA. A 55-year-old woman who had been on regular hemodialysis treatment for 7 yr suffered from RA for 10 yr. She was regularly treated with celecoxib, prednisolone, and sulfasalazine in the past year. Because of the increasing arthralgia, 7.5 mg per week MTX was prescribed 3 months before admission. Stomatitis, fever, general fatigue, multiple skin carbuncles, and easy bruising developed after a cumulative dose of 90 mg. Pancytopenia was found at admission and the nadir of white blood cell count was 250/microL with 28% neutrophils, hematocrit was 22%, and platelet count was 6000/microL. Eosinophil counts increased from 11.5% initially to 26.1% on the sixth admission day. Transfusion with red blood cells and platelets, and appropriate antibiotics and folic acid were prescribed. She continued receiving regular hemodialysis and eventually recovered within 3 weeks.

  4. 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

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

    Science.gov (United States)

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

    2014-01-01

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

  6. Effect of low doses gamma irradiation of cotton seeds

    International Nuclear Information System (INIS)

    Al-Oudat, M.; Khalifa, Kh.

    1996-01-01

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

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

    International Nuclear Information System (INIS)

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

    1999-01-01

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

  8. Medical effects of low doses of ionising radiation

    International Nuclear Information System (INIS)

    Coggle, J.E.

    1990-01-01

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

  9. Carcinogenesis in mice after low doses and dose rates

    International Nuclear Information System (INIS)

    Ullrich, R.L.

    1979-01-01

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

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

    Science.gov (United States)

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

    2018-02-01

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

  11. 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)

  12. 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)

  13. 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)

  14. 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)

  15. 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.

  16. 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.

  17. 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)

  18. 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)

  19. 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.)

  20. 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.

  1. 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.

  2. 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.

  3. Mathematical model for evaluation of dose-rate effect on biological responses to low dose γ-radiation

    International Nuclear Information System (INIS)

    Ogata, H.; Kawakami, Y.; Magae, J.

    2003-01-01

    Full text: To evaluate quantitative dose-response relationship on the biological response to radiation, it is necessary to consider a model including cumulative dose, dose-rate and irradiation time. In this study, we measured micronucleus formation and [ 3 H] thymidine uptake in human cells as indices of biological response to gamma radiation, and analyzed mathematically and statistically the data for quantitative evaluation of radiation risk at low dose/low dose-rate. Effective dose (ED x ) was mathematically estimated by fitting a general function of logistic model to the dose-response relationship. Assuming that biological response depends on not only cumulative dose but also dose-rate and irradiation time, a multiple logistic function was applied to express the relationship of the three variables. Moreover, to estimate the effect of radiation at very low dose, we proposed a modified exponential model. From the results of fitting curves to the inhibition of [ 3 H] thymidine uptake and micronucleus formation, it was obvious that ED 50 in proportion of inhibition of [ 3 H] thymidine uptake increased with longer irradiation time. As for the micronuclei, ED 30 also increased with longer irradiation times. These results suggest that the biological response depends on not only total dose but also irradiation time. The estimated response surface using the three variables showed that the biological response declined sharply when the dose-rate was less than 0.01 Gy/h. These results suggest that the response does not depend on total cumulative dose at very low dose-rates. Further, to investigate the effect of dose-rate within a wider range, we analyzed the relationship between ED x and dose-rate. Fitted curves indicated that ED x increased sharply when dose-rate was less than 10 -2 Gy/h. The increase of ED x signifies the decline of the response or the risk and suggests that the risk approaches to 0 at infinitely low dose-rate

  4. Lesion detection performance: comparative analysis of low-dose CT data of the chest on two hybrid imaging systems.

    Science.gov (United States)

    Jessop, Maryam; Thompson, John D; Coward, Joanne; Sanderud, Audun; Jorge, José; de Groot, Martijn; Lança, Luís; Hogg, Peter

    2015-03-01

    Incidental findings on low-dose CT images obtained during hybrid imaging are an increasing phenomenon as CT technology advances. Understanding the diagnostic value of incidental findings along with the technical limitations is important when reporting image results and recommending follow-up, which may result in an additional radiation dose from further diagnostic imaging and an increase in patient anxiety. This study assessed lesions incidentally detected on CT images acquired for attenuation correction on two SPECT/CT systems. An anthropomorphic chest phantom containing simulated lesions of varying size and density was imaged on an Infinia Hawkeye 4 and a Symbia T6 using the low-dose CT settings applied for attenuation correction acquisitions in myocardial perfusion imaging. Twenty-two interpreters assessed 46 images from each SPECT/CT system (15 normal images and 31 abnormal images; 41 lesions). Data were evaluated using a jackknife alternative free-response receiver-operating-characteristic analysis (JAFROC). JAFROC analysis showed a significant difference (P detection, with the figures of merit being 0.599 (95% confidence interval, 0.568, 0.631) and 0.810 (95% confidence interval, 0.781, 0.839) for the Infinia Hawkeye 4 and Symbia T6, respectively. Lesion detection on the Infinia Hawkeye 4 was generally limited to larger, higher-density lesions. The Symbia T6 allowed improved detection rates for midsized lesions and some lower-density lesions. However, interpreters struggled to detect small (5 mm) lesions on both image sets, irrespective of density. Lesion detection is more reliable on low-dose CT images from the Symbia T6 than from the Infinia Hawkeye 4. This phantom-based study gives an indication of potential lesion detection in the clinical context as shown by two commonly used SPECT/CT systems, which may assist the clinician in determining whether further diagnostic imaging is justified. © 2015 by the Society of Nuclear Medicine and Molecular Imaging

  5. Fluvoxamine stimulates oligodendrogenesis of cultured neural stem cells and attenuates inflammation and demyelination in an animal model of multiple sclerosis.

    Science.gov (United States)

    Ghareghani, Majid; Zibara, Kazem; Sadeghi, Heibatollah; Dokoohaki, Shima; Sadeghi, Hossein; Aryanpour, Roya; Ghanbari, Amir

    2017-07-07

    Multiple Sclerosis (MS) require medications controlling severity of the pathology and depression, affecting more than half of the patients. In this study, the effect of antidepressant drug fluvoxamine, a selective serotonin reuptake inhibitor, was investigated in vitro and in vivo. Nanomolar concentrations of fluvoxamine significantly increased cell viability and proliferation of neural stem cells (NSCs) through increasing mRNA expression of Notch1, Hes1 and Ki-67, and protein levels of NICD. Also, physiological concentrations of fluvoxamine were optimal for NSC differentiation toward oligodendrocytes, astrocytes and neurons. In addition, fluvoxamine attenuated experimental autoimmune encephalomyelitis (EAE) severity, a rat MS model, by significantly decreasing its clinical scores. Moreover, fluvoxamine treated EAE rats showed a decrease in IFN-γ serum levels and an increase in IL-4, pro- and anti-inflammatory cytokines respectively, compared to untreated EAE rats. Furthermore, immune cell infiltration and demyelination plaque significantly decreased in spinal cords of fluvoxamine-treated rats, which was accompanied by an increase in protein expression of MBP and GFAP positive cells and a decrease in lactate serum levels, a new biomarker of MS progression. In summary, besides its antidepressant activity, fluvoxamine stimulates proliferation and differentiation of NSCs particularly toward oligodendrocytes, a producer of CNS myelin.

  6. Natural Attenuation of Chlorinated Solvents Performance and Cost Results from Multiple Air Force Demonstration Sites, Technology Demonstration Slide Presentation

    National Research Council Canada - National Science Library

    Wiedemeier, Todd

    1999-01-01

    This slide presentation summarizes the results of natural attenuation treatability studies at 14 Air Force sites contaminated with chlorinated solvents and their associated biodegradation daughter products...

  7. Role of human recombinant activated protein C and low dose corticosteroid therapy in sepsis

    Directory of Open Access Journals (Sweden)

    Aparna Shukla

    2010-01-01

    Full Text Available Despite advances in modern medicine, sepsis remains a complex syndrome that has been associated with significant morbidity and mortality. Multiple organ failure associated with sepsis leads to high mortality and morbidity. About 28 - 50% deaths have been reported in patients with sepsis. The number of sepsis patients is increasing, with considerable burden on healthcare facilities. Various factors leading to a rise in the incidence of sepsis are (1 Improvement of diagnostic procedures (2 Increase in the number of immunocompromised patients taking treatment for various autoimmune disease, carcinomas, organ transplantation (3 Advances in intensive procedures (4 Nosocomial infections (5 Extensive use of antibiotics. With the better understanding of sepsis various modalities to modify pathophysiological response of septic patients have developed. Activated protein C and low-dose corticosteroid therapy have been tried in patients, with variable results.

  8. 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)

  9. 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.

  10. 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.

  11. 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)

  12. 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.

  13. 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

  14. 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

  15. 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.)

  16. Does the amount of tagged stool and fluid significantly affect the radiation exposure in low-dose CT colonography performed with an automatic exposure control?

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Hyun Kyong; Lee, Kyoung Ho; Kim, So Yeon; Kim, Young Hoon [Seoul National University Bundang Hospital, Department of Radiology, Seongnam-si, Gyeonggi-do (Korea, Republic of); Seoul National University College of Medicine, Seoul National University Medical Research Center, Institute of Radiation Medicine, Bundang (Korea, Republic of); Kim, Kil Joong [Seoul National University College of Medicine, Department of Radiation Applied Life Science, Seoul (Korea, Republic of); Kim, Bohyoung; Lee, Hyunna [Seoul National University, School of Computer Science and Engineering, Seoul (Korea, Republic of); Park, Seong Ho [University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Asan Medical Center, Seoul (Korea, Republic of); Yanof, Jeffrey H. [Philips Healthcare, CT Clinical Science, Cleveland, OH (United States); Hwang, Seung-sik [Inha University School of Medicine, Department of Social and Preventive Medicine, Incheon (Korea, Republic of)

    2011-02-15

    To determine whether the amount of tagged stool and fluid significantly affects the radiation exposure in low-dose screening CT colonography performed with an automatic tube-current modulation technique. The study included 311 patients. The tagging agent was barium (n = 271) or iodine (n = 40). Correlation was measured between mean volume CT dose index (CTDI{sub vol}) and the estimated x-ray attenuation of the tagged stool and fluid (ATT). Multiple linear regression analyses were performed to determine the effect of ATT on CTDI{sub vol} and the effect of ATT on image noise while adjusting for other variables including abdominal circumference. CTDI{sub vol} varied from 0.88 to 2.54 mGy. There was no significant correlation between CTDI{sub vol} and ATT (p = 0.61). ATT did not significantly affect CTDI{sub vol} (p = 0.93), while abdominal circumference was the only factor significantly affecting CTDI{sub vol} (p < 0.001). Image noise ranged from 59.5 to 64.1 HU. The p value for the regression model explaining the noise was 0.38. The amount of stool and fluid tagging does not significantly affect radiation exposure. (orig.)

  17. Does the amount of tagged stool and fluid significantly affect the radiation exposure in low-dose CT colonography performed with an automatic exposure control?

    International Nuclear Information System (INIS)

    Lim, Hyun Kyong; Lee, Kyoung Ho; Kim, So Yeon; Kim, Young Hoon; Kim, Kil Joong; Kim, Bohyoung; Lee, Hyunna; Park, Seong Ho; Yanof, Jeffrey H.; Hwang, Seung-sik

    2011-01-01

    To determine whether the amount of tagged stool and fluid significantly affects the radiation exposure in low-dose screening CT colonography performed with an automatic tube-current modulation technique. The study included 311 patients. The tagging agent was barium (n = 271) or iodine (n = 40). Correlation was measured between mean volume CT dose index (CTDI vol ) and the estimated x-ray attenuation of the tagged stool and fluid (ATT). Multiple linear regression analyses were performed to determine the effect of ATT on CTDI vol and the effect of ATT on image noise while adjusting for other variables including abdominal circumference. CTDI vol varied from 0.88 to 2.54 mGy. There was no significant correlation between CTDI vol and ATT (p = 0.61). ATT did not significantly affect CTDI vol (p = 0.93), while abdominal circumference was the only factor significantly affecting CTDI vol (p < 0.001). Image noise ranged from 59.5 to 64.1 HU. The p value for the regression model explaining the noise was 0.38. The amount of stool and fluid tagging does not significantly affect radiation exposure. (orig.)

  18. Ultra Low Dose Delta 9-Tetrahydrocannabinol Protects Mouse Liver from Ischemia Reperfusion Injury

    Directory of Open Access Journals (Sweden)

    Edith Hochhauser

    2015-07-01

    Full Text Available Background/Aims: Ischemia/reperfusion (I/R injury is the main cause of both primary graft dysfunction and primary non-function of liver allografts. Cannabinoids has been reported to attenuate myocardial, cerebral and hepatic I/R oxidative injury. Delta-9-tetrahydrocannabinol (THC, a cannabinoid agonist, is the active components of marijuana. In this study we examined the role of ultralow dose THC (0.002mg/kg in the protection of livers from I/R injury. This extremely low dose of THC was previously found by us to protect the mice brain and heart from a variety of insults. Methods: C57Bl Mice were studied in in vivo model of hepatic segmental (70% ischemia for 60min followed by reperfusion for 6 hours. Results: THC administration 2h prior to the induction of hepatic I/R was associated with significant attenuated elevations of: serum liver transaminases ALT and AST, the hepatic oxidative stress (activation of the intracellular signaling CREB pathway, the acute proinflammatory response (TNF-α, IL-1α, IL-10 and c-FOS hepatic mRNA levels, and ERK signaling pathway activation. This was followed by cell death (the cleavage of the pro-apoptotic caspase 3, DNA fragmentation and TUNEL after 6 hours of reperfusion. Significantly less hepatic injury was detected in the THC treated I/R mice and fewer apoptotic hepatocytes cells were identified by morphological criteria compared with untreated mice. Conclusion: A single ultralow dose THC can reduce the apoptotic, oxidative and inflammatory injury induced by hepatic I/R injury. THC may serve as a potential target for therapeutic intervention in hepatic I/R injury during liver transplantation, liver resection and trauma.

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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.

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

    International Nuclear Information System (INIS)

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

    2000-01-01

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

  6. Low dose reconstruction algorithm for differential phase contrast imaging.

    Science.gov (United States)

    Wang, Zhentian; Huang, Zhifeng; Zhang, Li; Chen, Zhiqiang; Kang, Kejun; Yin, Hongxia; Wang, Zhenchang; Marco, Stampanoni

    2011-01-01

    Differential phase contrast imaging computed tomography (DPCI-CT) is a novel x-ray inspection method to reconstruct the distribution of refraction index rather than the attenuation coefficient in weakly absorbing samples. In this paper, we propose an iterative reconstruction algorithm for DPCI-CT which benefits from the new compressed sensing theory. We first realize a differential algebraic reconstruction technique (DART) by discretizing the projection process of the differential phase contrast imaging into a linear partial derivative matrix. In this way the compressed sensing reconstruction problem of DPCI reconstruction can be transformed to a resolved problem in the transmission imaging CT. Our algorithm has the potential to reconstruct the refraction index distribution of the sample from highly undersampled projection data. Thus it can significantly reduce the dose and inspection time. The proposed algorithm has been validated by numerical simulations and actual experiments.

  7. Emesis as a Screening Diagnostic for Low Dose Rate (LDR) Total Body Radiation Exposure.

    Science.gov (United States)

    Camarata, Andrew S; Switchenko, Jeffrey M; Demidenko, Eugene; Flood, Ann B; Swartz, Harold M; Ali, Arif N

    2016-04-01

    Current radiation disaster manuals list the time-to-emesis (TE) as the key triage indicator of radiation dose. The data used to support TE recommendations were derived primarily from nearly instantaneous, high dose-rate exposures as part of variable condition accident databases. To date, there has not been a systematic differentiation between triage dose estimates associated with high and low dose rate (LDR) exposures, even though it is likely that after a nuclear detonation or radiologic disaster, many surviving casualties would have received a significant portion of their total exposure from fallout (LDR exposure) rather than from the initial nuclear detonation or criticality event (high dose rate exposure). This commentary discusses the issues surrounding the use of emesis as a screening diagnostic for radiation dose after LDR exposure. As part of this discussion, previously published clinical data on emesis after LDR total body irradiation (TBI) is statistically re-analyzed as an illustration of the complexity of the issue and confounding factors. This previously published data includes 107 patients who underwent TBI up to 10.5 Gy in a single fraction delivered over several hours at 0.02 to 0.04 Gy min. Estimates based on these data for the sensitivity of emesis as a screening diagnostic for the low dose rate radiation exposure range from 57.1% to 76.6%, and the estimates for specificity range from 87.5% to 99.4%. Though the original data contain multiple confounding factors, the evidence regarding sensitivity suggests that emesis appears to be quite poor as a medical screening diagnostic for LDR exposures.

  8. Comparison of biophysical factors influencing on emphysema quantification with low-dose CT

    Science.gov (United States)

    Heo, Chang Yong; Kim, Jong Hyo

    2014-03-01

    Emphysema Index(EI) measurements in MDCT is known to be influenced by various biophysical factors such as total lung volume, and body size. We investigated the association of the four biophysical factors with emphysema index in low-dose MDCT. In particular, we attempted to identify a potentially stronger biophysical factor than total lung volume. A total of 400 low-dose MDCT volumes taken at 120kVp, 40mAs, 1mm thickness, and B30f reconstruction kernel were used. The lungs, airways, and pulmonary vessels were automatically segmented, and two Emphysema Indices, relative area below -950HU(RA950) and 15th percentile(Perc15), were extracted from the segmented lungs. The biophysical factors such as total lung volume(TLV), mode of lung attenuation(ModLA), effective body diameter(EBD), and the water equivalent body diameter(WBD) were estimated from the segmented lung and body area. The association of biophysical factors with emphysema indices were evaluated by correlation coefficients. The mean emphysema indices were 8.3±5.5(%) in RA950, and -930±18(HU) in Perc15. The estimates of biophysical factors were 4.7±1.0(L) in TLV, -901±21(HU) in ModLA, 26.9±2.2(cm) in EBD, and 25.9±2.6(cm) in WBD. The correlation coefficients of biophysical factors with RA950 were 0.73 in TLV, 0.94 in ModLA, 0.31 in EBD, and 0.18 WBD, the ones with Perc15 were 0.74 in TLV, 0.98 in ModLA, 0.29 in EBD, and 0.15 WBD. Study results revealed that two biophysical factors, TLV and ModLA, mostly affects the emphysema indices. In particular, the ModLA exhibited strongest correlation of 0.98 with Perc15, which indicating the ModLA is the most significant confounding biophysical factor in emphysema indices measurement.

  9. 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)

  10. 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)

  11. 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

  12. Effects of low-dose IV ketamine on peripheral and central pain from major limb injuries sustained in combat.

    Science.gov (United States)

    Polomano, Rosemary C; Buckenmaier, Chester C; Kwon, Kyung H; Hanlon, Alexandra L; Rupprecht, Christine; Goldberg, Cynthia; Gallagher, Rollin M

    2013-07-01

    Examine response patterns to low-dose intravenous (IV) ketamine continuous infusions on multiple pain outcomes, and demonstrate effectiveness, safety, and tolerability of ketamine administration on general wards. Retrospective case series of consecutive patients given low-dose IV ketamine continuous infusions. Walter Reed Army Medical Center, Washington, DC. Nineteen eligible inpatients with neuropathic pain from major limb injuries sustained in combat with inadequate pain control from multimodal analgesia. A 3-day IV infusion of ketamine at doses ≤ 120 μg/kg/h. Daily present (PPI), average (API), and worst (WPI) pain intensity (0-10), global pain relief (GPR) (1 "no relief" to 5 "complete relief"), daily assessments of adverse events, and daily opioid requirements measured during therapy. A significant reduction in PPI (P pain (PLP) (N = 10; P = 0.0436) were observed. Mean percent increase in overall GPR was better for those reporting GPR scores ≤ 3 (N = 13) in the first 24 hours of therapy (P = 0.0153). While not significant, mean opioid requirement (IV morphine equivalents) decreased from 129.9 mgs ± 137.3 on day 1 to 112.14 ± 86.3 24 hours after therapy. Low-dose ketamine infusions for complex combat injury pain were safe and effective, and demonstrated response patterns over time and by baseline pain score stratification and presence or absence of PLP. Wiley Periodicals, Inc.

  13. CORK Study in Cystic Fibrosis: Sustained Improvements in Ultra-Low-Dose Chest CT Scores After CFTR Modulation With Ivacaftor.

    Science.gov (United States)

    Ronan, Nicola J; Einarsson, Gisli G; Twomey, Maria; Mooney, Denver; Mullane, David; NiChroinin, Muireann; O'Callaghan, Grace; Shanahan, Fergus; Murphy, Desmond M; O'Connor, Owen J; Shortt, Cathy A; Tunney, Michael M; Eustace, Joseph A; Maher, Michael M; Elborn, J Stuart; Plant, Barry J

    2018-02-01

    Ivacaftor produces significant clinical benefit in patients with cystic fibrosis (CF) with the G551D mutation. Prevalence of this mutation at the Cork CF Centre is 23%. This study assessed the impact of cystic fibrosis transmembrane conductance regulator modulation on multiple modalities of patient assessment. Thirty-three patients with the G551D mutation were assessed at baseline and prospectively every 3 months for 1 year after initiation of ivacaftor. Change in ultra-low-dose chest CT scans, blood inflammatory mediators, and the sputum microbiome were assessed. Significant improvements in FEV 1 , BMI, and sweat chloride levels were observed post-ivacaftor treatment. Improvement in ultra-low-dose CT imaging scores were observed after treatment, with significant mean reductions in total Bhalla score (P < .01), peribronchial thickening (P = .035), and extent of mucous plugging (P < .001). Reductions in circulating inflammatory markers, including interleukin (IL)-1β, IL-6, and IL-8 were demonstrated. There was a 30% reduction in the relative abundance of Pseudomonas species and an increase in the relative abundance of bacteria associated with more stable community structures. Posttreatment community richness increased significantly (P = .03). Early and sustained improvements on ultra-low-dose CT scores suggest it may be a useful method of evaluating treatment response. It paralleled improvement in symptoms, circulating inflammatory markers, and changes in the lung microbiota. Copyright © 2017 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

  14. The reduction of image noise and streak artifact in the thoracic inlet during low dose and ultra-low dose thoracic CT

    International Nuclear Information System (INIS)

    Paul, N S; Prezelj, E; Burey, P; Menezes, R J; Blobel, J; Ursani, A; Kashani, H; Siewerdsen, J H

    2010-01-01

    Increased pixel noise and streak artifact reduce CT image quality and limit the potential for radiation dose reduction during CT of the thoracic inlet. We propose to quantify the pixel noise of mediastinal structures in the thoracic inlet, during low-dose (LDCT) and ultralow-dose (uLDCT) thoracic CT, and assess the utility of new software (quantum denoising system and BOOST3D) in addressing these limitations. Twelve patients had LDCT (120 kV, 25 mAs) and uLDCT (120 kV, 10 mAs) images reconstructed initially using standard mediastinal and lung filters followed by the quantum denoising system (QDS) to reduce pixel noise and BOOST3D (B3D) software to correct photon starvation noise as follows: group 1 no QDS, no B3D; group 2 B3D alone; group 3 QDS alone and group 4 both QDS and B3D. Nine regions of interest (ROIs) were replicated on mediastinal anatomy in the thoracic inlet, for each patient resulting in 3456 data points to calculate pixel noise and attenuation. QDS reduced pixel noise by 18.4% (lung images) and 15.8% (mediastinal images) at 25 mAs. B3D reduced pixel noise by ∼8% in the posterior thorax and in combination there was a 35.5% reduction in effective radiation dose (E) for LDCT (1.63-1.05 mSv) in lung images and 32.2% (1.55-1.05 mSv) in mediastinal images. The same combination produced 20.7% reduction (0.53-0.42 mSv) in E for uLDCT, for lung images and 17.3% (0.51-0.42) for mediastinal images. This quantitative analysis of image quality confirms the utility of dedicated processing software in targeting image noise and streak artifact in thoracic LDCT and uLDCT images taken in the thoracic inlet. This processing software potentiates substantial reductions in radiation dose during thoracic LDCT and uLDCT.

  15. Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead.

    Science.gov (United States)

    Goodson, William H; Lowe, Leroy; Carpenter, David O; Gilbertson, Michael; Manaf Ali, Abdul; Lopez de Cerain Salsamendi, Adela; Lasfar, Ahmed; Carnero, Amancio; Azqueta, Amaya; Amedei, Amedeo; Charles, Amelia K; Collins, Andrew R; Ward, Andrew; Salzberg, Anna C; Colacci, Annamaria; Olsen, Ann-Karin; Berg, Arthur; Barclay, Barry J; Zhou, Binhua P; Blanco-Aparicio, Carmen; Baglole, Carolyn J; Dong, Chenfang; Mondello, Chiara; Hsu, Chia-Wen; Naus, Christian C; Yedjou, Clement; Curran, Colleen S; Laird, Dale W; Koch, Daniel C; Carlin, Danielle J; Felsher, Dean W; Roy, Debasish; Brown, Dustin G; Ratovitski, Edward; Ryan, Elizabeth P; Corsini, Emanuela; Rojas, Emilio; Moon, Eun-Yi; Laconi, Ezio; Marongiu, Fabio; Al-Mulla, Fahd; Chiaradonna, Ferdinando; Darroudi, Firouz; Martin, Francis L; Van Schooten, Frederik J; Goldberg, Gary S; Wagemaker, Gerard; Nangami, Gladys N; Calaf, Gloria M; Williams, Graeme; Wolf, Gregory T; Koppen, Gudrun; Brunborg, Gunnar; Lyerly, H Kim; Krishnan, Harini; Ab Hamid, Hasiah; Yasaei, Hemad; Sone, Hideko; Kondoh, Hiroshi; Salem, Hosni K; Hsu, Hsue-Yin; Park, Hyun Ho; Koturbash, Igor; Miousse, Isabelle R; Scovassi, A Ivana; Klaunig, James E; Vondráček, Jan; Raju, Jayadev; Roman, Jesse; Wise, John Pierce; Whitfield, Jonathan R; Woodrick, Jordan; Christopher, Joseph A; Ochieng, Josiah; Martinez-Leal, Juan Fernando; Weisz, Judith; Kravchenko, Julia; Sun, Jun; Prudhomme, Kalan R; Narayanan, Kannan Badri; Cohen-Solal, Karine A; Moorwood, Kim; Gonzalez, Laetitia; Soucek, Laura; Jian, Le; D'Abronzo, Leandro S; Lin, Liang-Tzung; Li, Lin; Gulliver, Linda; McCawley, Lisa J; Memeo, Lorenzo; Vermeulen, Louis; Leyns, Luc; Zhang, Luoping; Valverde, Mahara; Khatami, Mahin; Romano, Maria Fiammetta; Chapellier, Marion; Williams, Marc A; Wade, Mark; Manjili, Masoud H; Lleonart, Matilde E; Xia, Menghang; Gonzalez, Michael J; Karamouzis, Michalis V; Kirsch-Volders, Micheline; Vaccari, Monica; Kuemmerle, Nancy B; Singh, Neetu; Cruickshanks, Nichola; Kleinstreuer, Nicole; van Larebeke, Nik; Ahmed, Nuzhat; Ogunkua, Olugbemiga; Krishnakumar, P K; Vadgama, Pankaj; Marignani, Paola A; Ghosh, Paramita M; Ostrosky-Wegman, Patricia; Thompson, Patricia A; Dent, Paul; Heneberg, Petr; Darbre, Philippa; Sing Leung, Po; Nangia-Makker, Pratima; Cheng, Qiang Shawn; Robey, R Brooks; Al-Temaimi, Rabeah; Roy, Rabindra; Andrade-Vieira, Rafaela; Sinha, Ranjeet K; Mehta, Rekha; Vento, Renza; Di Fiore, Riccardo; Ponce-Cusi, Richard; Dornetshuber-Fleiss, Rita; Nahta, Rita; Castellino, Robert C; Palorini, Roberta; Abd Hamid, Roslida; Langie, Sabine A S; Eltom, Sakina E; Brooks, Samira A; Ryeom, Sandra; Wise, Sandra S; Bay, Sarah N; Harris, Shelley A; Papagerakis, Silvana; Romano, Simona; Pavanello, Sofia; Eriksson, Staffan; Forte, Stefano; Casey, Stephanie C; Luanpitpong, Sudjit; Lee, Tae-Jin; Otsuki, Takemi; Chen, Tao; Massfelder, Thierry; Sanderson, Thomas; Guarnieri, Tiziana; Hultman, Tove; Dormoy, Valérian; Odero-Marah, Valerie; Sabbisetti, Venkata; Maguer-Satta, Veronique; Rathmell, W Kimryn; Engström, Wilhelm; Decker, William K; Bisson, William H; Rojanasakul, Yon; Luqmani, Yunus; Chen, Zhenbang; Hu, Zhiwei

    2015-06-01

    Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety 'Mode of Action' framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology. © The Author 2015. Published by Oxford University Press.

  16. 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)

  17. Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead

    Science.gov (United States)

    Goodson, William H.; Lowe, Leroy; Carpenter, David O.; Gilbertson, Michael; Manaf Ali, Abdul; Lopez de Cerain Salsamendi, Adela; Lasfar, Ahmed; Carnero, Amancio; Azqueta, Amaya; Amedei, Amedeo; Charles, Amelia K.; Collins, Andrew R.; Ward, Andrew; Salzberg, Anna C.; Colacci, Anna Maria; Olsen, Ann-Karin; Berg, Arthur; Barclay, Barry J.; Zhou, Binhua P.; Blanco-Aparicio, Carmen; Baglole, Carolyn J.; Dong, Chenfang; Mondello, Chiara; Hsu, Chia-Wen; Naus, Christian C.; Yedjou, Clement; Curran, Colleen S.; Laird, Dale W.; Koch, Daniel C.; Carlin, Danielle J.; Felsher, Dean W.; Roy, Debasish; Brown, Dustin G.; Ratovitski, Edward; Ryan, Elizabeth P.; Corsini, Emanuela; Rojas, Emilio; Moon, Eun-Yi; Laconi, Ezio; Marongiu, Fabio; Al-Mulla, Fahd; Chiaradonna, Ferdinando; Darroudi, Firouz; Martin, Francis L.; Van Schooten, Frederik J.; Goldberg, Gary S.; Wagemaker, Gerard; Nangami, Gladys N.; Calaf, Gloria M.; Williams, Graeme P.; Wolf, Gregory T.; Koppen, Gudrun; Brunborg, Gunnar; Lyerly, H. Kim; Krishnan, Harini; Ab Hamid, Hasiah; Yasaei, Hemad; Sone, Hideko; Kondoh, Hiroshi; Salem, Hosni K.; Hsu, Hsue-Yin; Park, Hyun Ho; Koturbash, Igor; Miousse, Isabelle R.; Scovassi, A.Ivana; Klaunig, James E.; Vondráček, Jan; Raju, Jayadev; Roman, Jesse; Wise, John Pierce; Whitfield, Jonathan R.; Woodrick, Jordan; Christopher, Joseph A.; Ochieng, Josiah; Martinez-Leal, Juan Fernando; Weisz, Judith; Kravchenko, Julia; Sun, Jun; Prudhomme, Kalan R.; Narayanan, Kannan Badri; Cohen-Solal, Karine A.; Moorwood, Kim; Gonzalez, Laetitia; Soucek, Laura; Jian, Le; D’Abronzo, Leandro S.; Lin, Liang-Tzung; Li, Lin; Gulliver, Linda; McCawley, Lisa J.; Memeo, Lorenzo; Vermeulen, Louis; Leyns, Luc; Zhang, Luoping; Valverde, Mahara; Khatami, Mahin; Romano, Maria Fiammetta; Chapellier, Marion; Williams, Marc A.; Wade, Mark; Manjili, Masoud H.; Lleonart, Matilde E.; Xia, Menghang; Gonzalez Guzman, Michael J.; Karamouzis, Michalis V.; Kirsch-Volders, Micheline; Vaccari, Monica; Kuemmerle, Nancy B.; Singh, Neetu; Cruickshanks, Nichola; Kleinstreuer, Nicole; van Larebeke, Nik; Ahmed, Nuzhat; Ogunkua, Olugbemiga; Krishnakumar, P.K.; Vadgama, Pankaj; Marignani, Paola A.; Ghosh, Paramita M.; Ostrosky-Wegman, Patricia; Thompson, Patricia A.; Dent, Paul; Heneberg, Petr; Darbre, Philippa; Leung, Po Sing; Nangia-Makker, Pratima; Cheng, Qiang (Shawn); Robey, R.Brooks; Al-Temaimi, Rabeah; Roy, Rabindra; Andrade-Vieira, Rafaela; Sinha, Ranjeet K.; Mehta, Rekha; Vento, Renza; Di Fiore, Riccardo; Ponce-Cusi, Richard; Dornetshuber-Fleiss, Rita; Nahta, Rita; Castellino, Robert C.; Palorini, Roberta; Hamid, Roslida A.; Langie, Sabine A.S.; Eltom, Sakina E.; Brooks, Samira A.; Ryeom, Sandra; Wise, Sandra S.; Bay, Sarah N.; Harris, Shelley A.; Papagerakis, Silvana; Romano, Simona; Pavanello, Sofia; Eriksson, Staffan; Forte, Stefano; Casey, Stephanie C.; Luanpitpong, Sudjit; Lee, Tae-Jin; Otsuki, Takemi; Chen, Tao; Massfelder, Thierry; Sanderson, Thomas; Guarnieri, Tiziana; Hultman, Tove; Dormoy, Valérian; Odero-Marah, Valerie; Sabbisetti, Venkata; Maguer-Satta, Veronique; Rathmell, W.Kimryn; Engström, Wilhelm; Decker, William K.; Bisson, William H.; Rojanasakul, Yon; Luqmani, Yunus; Chen, Zhenbang; Hu, Zhiwei

    2015-01-01

    Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety ‘Mode of Action’ framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology. PMID:26106142

  18. Low-dose gonadotropin induction of ovulation in anovulatory women - still needed in the age of IVF.

    Science.gov (United States)

    White, Davinia; Hardy, Kate; Lovelock, Suzannah; Franks, Stephen

    2018-02-19

    Low-dose, step-up gonadotropin is the treatment of choice for women with PCOS who have not conceived after anti-estrogen treatment, and as an effective alternative to pulsatile GnRH in women with hypogonadotropic hypogonadism (HH). There has been, however, no large-scale, comparative study between the two groups using low-dose gonadotropins. Here we performed a retrospective, comparative analysis, in a single clinic database, of efficacy and safety of induction of ovulation using low-dose gonadotropins in 364 Women with PCOS and 80 women with HH. The rate of ovulation was high in both PCOS (83%) and HH (84%) but mono-follicular, ovulatory cycles were more prevalent in PCOS than in HH (77% vs 53%, p<0.0001) and the proportion of cycles that were abandoned was higher in HH than in PCOS (25% vs 15%, p<0.0001). The median threshold dose of gonadotropin required to induce ovulation was 75iu/day in PCOS and 113iu/day in HH (p<0.001) and the range of doses was greater in HH women. Forty-nine percent of women with PCOS and 65% of those with HH conceived (more than 90% within 6 cycles of treatment) and had a least one pregnancy. Multiple pregnancies (all twins) occurred in only 4% of women with PCOS and 5% of those with HH. These findings emphasise the efficacy and safety of low-dose gonadotropin treatment for both clomiphene-resistant women with PCOS and those with HH. These results highlight the importance of choosing the more physiological approach of gonadotropin induction of ovulation in both groups as the most appropriate treatment, in preference to IVF.

  19. 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.

  20. 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.

  1. 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.

  2. 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)

  3. 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

  4. Low Dose Radiation Cancer Risks: Epidemiological and Toxicological Models

    Energy Technology Data Exchange (ETDEWEB)

    David G. Hoel, PhD

    2012-04-19

    The basic purpose of this one year research grant was to extend the two stage clonal expansion model (TSCE) of carcinogenesis to exposures other than the usual single acute exposure. The two-stage clonal expansion model of carcinogenesis incorporates the biological process of carcinogenesis, which involves two mutations and the clonal proliferation of the intermediate cells, in a stochastic, mathematical way. The current TSCE model serves a general purpose of acute exposure models but requires numerical computation of both the survival and hazard functions. The primary objective of this research project was to develop the analytical expressions for the survival function and the hazard function of the occurrence of the first cancer cell for acute, continuous and multiple exposure cases within the framework of the piece-wise constant parameter two-stage clonal expansion model of carcinogenesis. For acute exposure and multiple exposures of acute series, it is either only allowed to have the first mutation rate vary with the dose, or to have all the parameters be dose dependent; for multiple exposures of continuous exposures, all the parameters are allowed to vary with the dose. With these analytical functions, it becomes easy to evaluate the risks of cancer and allows one to deal with the various exposure patterns in cancer risk assessment. A second objective was to apply the TSCE model with varing continuous exposures from the cancer studies of inhaled plutonium in beagle dogs. Using step functions to estimate the retention functions of the pulmonary exposure of plutonium the multiple exposure versions of the TSCE model was to be used to estimate the beagle dog lung cancer risks. The mathematical equations of the multiple exposure versions of the TSCE model were developed. A draft manuscript which is attached provides the results of this mathematical work. The application work using the beagle dog data from plutonium exposure has not been completed due to the fact

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

    Directory of Open Access Journals (Sweden)

    Dimberg Lina Y

    2012-07-01

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

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

    International Nuclear Information System (INIS)

    Dimberg, Lina Y; Nilsson, Kenneth; Öberg, Fredrik; Wiklund, Helena Jernberg; Dimberg, Anna; Ivarsson, Karolina; Fryknäs, Mårten; Rickardson, Linda; Tobin, Gerard; Ekman, Simon; Larsson, Rolf; Gullberg, Urban

    2012-01-01

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

  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. 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.

  9. Pharmacological stimulation of p53 with low-dose doxorubicin ameliorates diet-induced nonalcoholic steatosis and steatohepatitis

    Directory of Open Access Journals (Sweden)

    Begoña Porteiro

    2018-02-01

    Full Text Available Objective: Recent reports have implicated the p53 tumor suppressor in the regulation of lipid metabolism. We hypothesized that the pharmacological activation of p53 with low-dose doxorubicin, which is widely used to treat several types of cancer, may have beneficial effects on nonalcoholic fatty liver disease (NAFLD and nonalcoholic steatohepatitis (NASH. Methods: We used long-term pharmacological activation of p53 by i.p. or oral administration of low-dose doxorubicin in different animal models of NAFLD (high fat diet containing 45% and 60% kcal fat and NASH (methionine- and choline-deficient diet and choline deficiency combined with high fat diet. We also administered doxorubicin in mice lacking p53 in the liver and in two human hepatic cells lines (HepG2 and THLE2. Results: The attenuation of liver damage was accompanied by the stimulation of fatty acid oxidation and decrease of lipogenesis, inflammation, and ER stress. The effects of doxorubicin were abrogated in mice with liver-specific ablation of p53. Finally, the effects of doxorubicin on lipid metabolism found in animal models were also present in two human hepatic cells lines, in which the drug stimulated fatty acid oxidation and inhibited de novo lipogenesis at doses that did not cause changes in apoptosis or cell viability. Conclusion: These data provide new evidence for targeting p53 as a strategy to treat liver disease. Keywords: Obesity, Lipid metabolism, Inflammation

  10. Effect of low dose of gamma radiation on the induction and signalling of complex damages of DNA in the mammals cells

    International Nuclear Information System (INIS)

    Boucher, D.

    2006-09-01

    The work presented in the frame of this thesis are in line with the studies on the radioinduced damages of DNA in order to better understand their genotoxic effects and the associated risks. The different radioinduced damages of DNA are given, the complex damages, double strand-break and multiple damages are particularly detailed as well as their methods of detection. Are presented the systems implemented in the cell in order to point the radioinduced damages and to implement the repair systems of these lesions. Then, are presented the knowledge on the effects of low doses and low dose rates. The whole of this work has for objective to highlight the mechanisms by which the reduction of dose rate allows an increase of cell survival. By a better knowledge of the system implemented in response to a low dose rate irradiation, it is possible to valid or not the linear without threshold model of low doses effects and consequently to better understand the eventual risks of cancer linked to exposures of low doses of ionizing radiation. (N.C.)

  11. Evaluation of low doses of gamma irradiation in the formation of mineralization nodules in osteoblasts culture

    Energy Technology Data Exchange (ETDEWEB)

    Targino, Bárbara; Pinto, Thais Lazarine; Silva, Evily Fernandes; Somessari, E.S.R.; Bellini, Maria Helena; Affonso, Regina [Instituto De Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

    2017-07-01

    stained with Alizarin red S (Sigma). All in three biological replicates (a total of 54 samples) and multiple comparisons were assessed by One-way ANOVA followed by Bonferroni's tests with GraphPad Prism version 6.0 software. P< 0.05 was considered statistically significant. Results: Plating efficiency (PF) analysis is generally considered to be the gold standard of assays for testing the sensitivity of cell lines to ionizing radiation or other cytotoxic agents in vitro. The results obtained were a PF of 30% for non-irradiated culture, however, the irradiated culture obtained 40% in relation to the no-irradiated one, already with 0.5 Gy, and this percentage was maintained in the other larger doses. Regarding the evaluation of the formation of mineralization nodules, significant difference in 0.5 Gy group was observed compared with the control group (0 Gy), 64.7±1.8 and 53.0±0.9, respectively. The groups of 1.0, 1.5 and 2.0 Gy obtained a decrease in the mineralization nodules. The data obtained with increasing irradiation produced an increase of mineralization nodules up to 0.5 Gy and in the higher doses had a decrease. Applying the data in a non-linear function it is observed that the line has a decreasing tendency with the negative angular coefficient. This analysis is in agreement with the hormesis model, in which low doses induce a stimulatory effect while high doses cause inhibition4. Conclusions: This study is one among the first that investigating the biophysics of low-dose gamma-irradiation on MC3T3-E1 culture, focusing on the potential applications in bone replacement therapy. (author)

  12. Evaluation of low doses of gamma irradiation in the formation of mineralization nodules in osteoblasts culture

    International Nuclear Information System (INIS)

    Targino, Bárbara; Pinto, Thais Lazarine; Silva, Evily Fernandes; Somessari, E.S.R.; Bellini, Maria Helena; Affonso, Regina

    2017-01-01

    stained with Alizarin red S (Sigma). All in three biological replicates (a total of 54 samples) and multiple comparisons were assessed by One-way ANOVA followed by Bonferroni's tests with GraphPad Prism version 6.0 software. P< 0.05 was considered statistically significant. Results: Plating efficiency (PF) analysis is generally considered to be the gold standard of assays for testing the sensitivity of cell lines to ionizing radiation or other cytotoxic agents in vitro. The results obtained were a PF of 30% for non-irradiated culture, however, the irradiated culture obtained 40% in relation to the no-irradiated one, already with 0.5 Gy, and this percentage was maintained in the other larger doses. Regarding the evaluation of the formation of mineralization nodules, significant difference in 0.5 Gy group was observed compared with the control group (0 Gy), 64.7±1.8 and 53.0±0.9, respectively. The groups of 1.0, 1.5 and 2.0 Gy obtained a decrease in the mineralization nodules. The data obtained with increasing irradiation produced an increase of mineralization nodules up to 0.5 Gy and in the higher doses had a decrease. Applying the data in a non-linear function it is observed that the line has a decreasing tendency with the negative angular coefficient. This analysis is in agreement with the hormesis model, in which low doses induce a stimulatory effect while high doses cause inhibition4. Conclusions: This study is one among the first that investigating the biophysics of low-dose gamma-irradiation on MC3T3-E1 culture, focusing on the potential applications in bone replacement therapy. (author)

  13. The Acute Effects of Low-Dose TNF-α on Glucose Metabolism and β-Cell Function in Humans

    DEFF Research Database (Denmark)

    Ibfelt, Tobias; Fischer, Christian Philip; Plomgaard, Peter

    2014-01-01

    , nondiabetic young men (n = 10) during a 4-hour basal period followed by an intravenous glucose tolerance test (IVGTT). TNF-α lowered insulin levels by 12% during the basal period (P levels increased markedly in both trials, but there was no difference between trials......Type 2 diabetes is characterized by increased insulin resistance and impaired insulin secretion. Type 2 diabetes is also associated with low-grade inflammation and increased levels of proinflammatory cytokines such as TNF-α. TNF-α has been shown to impair peripheral insulin signaling in vitro...... and in vivo. However, it is unclear whether TNF-α may also affect endogenous glucose production (EGP) during fasting and glucose-stimulated insulin secretion (GSIS) in vivo. We hypothesized that low-dose TNF- α would increase EGP and attenuate GSIS. Recombinant human TNF-α or placebo was infused in healthy...

  14. Calculation of the flux attenuation and multiple scattering correction factors in time of flight technique for double differential cross section measurements

    International Nuclear Information System (INIS)

    Martin, G.; Coca, M.; Capote, R.

    1996-01-01

    Using Monte Carlo method technique , a computer code which simulates the time of flight experiment to measure double differential cross section was developed. The correction factor for flux attenuation and multiple scattering, that make a deformation to the measured spectrum, were calculated. The energy dependence of the correction factor was determined and a comparison with other works is shown. Calculations for Fe 56 at two different scattering angles were made. We also reproduce the experiment performed at the Nuclear Analysis Laboratory for C 12 at 25 celsius degree and the calculated correction factor for the is measured is shown. We found a linear relation between the scatter size and the correction factor for flux attenuation

  15. 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)

  16. 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.

  17. 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.

  18. Thyroid neoplasia following low-dose radiation in childhood

    International Nuclear Information System (INIS)

    Ron, E.; Modan, B.; Preston, D.; Alfandary, E.; Stovall, M.; Boice, J.D. Jr.

    1989-01-01

    The thyroid gland is highly sensitive to the carcinogenic effects of ionizing radiation. Previously, we reported a significant increase of thyroid cancer and adenomas among 10,834 persons in Israel who received radiotherapy to the scalp for ringworm. These findings have now been extended with further follow-up and revised dosimetry. Overall, 98 thyroid tumors were identified among the exposed and 57 among 10,834 nonexposed matched population and 5392 sibling comparison subjects. An estimated thyroid dose of 9 cGy was linked to a fourfold (95% Cl = 2.3-7.9) increase of malignant tumors and a twofold (95% Cl = 1.3-3.0) increase of benign tumors. The dose-response relationship was consistent with linearity. Age was an important modifier of risk with those exposed under 5 years being significantly more prone to develop thyroid tumors than older children. The pattern of radiation risk over time could be described on the basis of a constant multiplication of the background rate, and an absolute risk model was not compatible with the observed data. Overall, the excess relative risk per cGy for thyroid cancer development after childhood exposure is estimated as 0.3, and the absolute excess risk as 13 per 10(6) PY-cGy. For benign tumors the estimated excess relative risk was 0.1 per cGy and the absolute risk was 15 per 10(6) PY-cGy

  19. 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)

  20. 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

  1. Low-dose exposure to Veratrum album in children causes mild effects--a case series.

    Science.gov (United States)

    Rauber-Lüthy, Christine; Halbsguth, Ulrike; Kupferschmidt, Hugo; König, Naoko; Mégevand, Chloé; Zihlmann, Karin; Ceschi, Alessandro

    2010-03-01

    White or false hellebore (Veratrum album) has a toxicological relevance because of the potential for misidentification of this plant as yellow gentian (Gentiana lutea). We report a retrospective case series of 11 children (8-12 years) with accidental intake of V. album at a youth camp where they had collected herbs for preparing fresh herb tea. Two children (18%) remained asymptomatic. Nine (82%) developed mild gastrointestinal symptoms, six (55%) presented neurological symptoms, and three (27%) showed bradycardia. All children recovered completely within 10 h of ingestion. The plant was identified at the emergency department; however, detection of veratridine and cevadine by means of high-performance liquid chromatography-Mass spectrometry from the blood of the child with the most severe symptoms was negative (limit 0.01 ng/mL). Veratrum species contain more than 200 different alkaloids, which are the principal toxins and are responsible for most clinical symptoms. There are likely multiple mechanisms of toxicity and some of them are only partially understood. The opening of voltage-gated sodium channels is probably one of the most relevant pathophysiological mechanisms. Veratrum album intoxication in children demonstrated the same clinical course as observed in adults. Accidental ingestion of a low dose of the plant had a favorable outcome with supportive care.

  2. 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

  3. Evaluating low dose ionizing radiation effects on gene expression in human skin biopsy cores

    International Nuclear Information System (INIS)

    Goldberg, Z.; Schwietert, C.; Stern, R.L.; Lehnert, B.E.

    2003-01-01

    Significant biological effects can occur in animals, animal cells, immortalized human cell lines, and primary human cells after exposure to doses of ionizing radiation (IR) in the <1-10 cGy region. However it is unclear how these observations mimic or even pertain to the actual in vivo condition in humans, though such knowledge is required for reducing the uncertainty of assessing human risks due to low dose IR (LDIR) exposures. Further, low dose effects have increasing clinical relevance in the radiotherapeutic management of cancer as the volume of tissue receiving only LDIR increases as more targeted radiotherapy (i.e. IMRT) becomes more widely used. Thus, human translational data must be obtained with which to correlate in vitro experimental findings and evaluate their 'real-life' applicability. To evaluate LDIR effects in human tissue we have obtained freshly explanted full thickness human skin samples obtained from aesthetic surgery, and subjected them to ex vivo irradiation as a translational research model system of a complex human tissue. Ionizing radiation (IR) exposures were delivered at 1, 10, or 100 cGy. The temporal response to IR was assessed by harvesting RNA at multiple time points out to 24 hours post IR. Gene expression changes were assessed by real time PCR. We have shown that RNA can be reliably extracted with fidelity from 3 mm diameter punch biopsies of human tissue and provide good quality sample for the real time PCR evaluation. Genes of interest include those reported to have altered expression following LDIR from in vitro cell culture models. These include genes associated with cell cycle regulation, DNA repair and various cytokines. These feasibility studies in human skin irradiated ex vivo, have demonstrated that gene expression can be measured accurately from very small human tissue samples, thus setting the stage for biopsy acquisition of tissue irradiated in vivo from patients-volunteers. The clinical study has begun and the data from

  4. 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.

  5. 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

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.)

  11. 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...

  12. 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.

  13. Acute hematological tolerance to multiple fraction, whole body, low dose irradiation in an experimental murine system

    International Nuclear Information System (INIS)

    Melamed, J.S.; Chen, M.G.; Brown, J.W.; Katagiri, C.A.

    1980-01-01

    Using a dose fractionation scheme patterned after the current regimen for treatment of disseminated non-Hodgkin lymphoma, the authors studied the effects of irradation on progenitor and effector cells for hematopoiesis in five-month-old BC3F 1 mice. Fractions of 20 or 50 rad (0.2 or 0.5 Gy) total body irradation were given twice weekly to a final total dose of 200 or 500 rad (2 or 5 Gy), respectively. Weekly assays revealed a marked, sustained depression of stem cell activity, measured as numbers of spleen colony-forming units (CFU-S) and in vitro colony-forming cells (CFU-C), without corresponding depression of effector cells (red and white cells, and platelets). The lack of correlation between numbers of stem cells and peripheral elements is relevant to clinical assessment of marrow reserve

  14. 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)

  15. 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)

  16. 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.

  17. 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...

  18. 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)

  19. 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

  20. 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.

  1. 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)

  2. 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.

  3. 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.

  4. 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.

  5. 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)

  6. Extracting Gene Networks for Low-Dose Radiation Using Graph Theoretical Algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Voy, Brynn H [ORNL; Scharff, Jon [University of Tennessee, Knoxville (UTK); Perkins, Andy [University of Tennessee, Knoxville (UTK); Saxton, Arnold [University of Tennessee, Knoxville (UTK); Borate, Bhavesh [University of Tennessee, Knoxville (UTK); Chesler, Elissa J [ORNL; Branstetter, Lisa R [ORNL; Langston, Michael A [University of Tennessee, Knoxville (UTK)

    2006-01-01

    Genes with common functions often exhibit correlated expression levels, which can be used to identify sets of interacting genes from microarray data. Microarrays typically measure expression across genomic space, creating a massive matrix of co-expression that must be mined to extract only the most relevant gene interactions. We describe a graph theoretical approach to extracting co-expressed sets of genes, based on the computation of cliques. Unlike the results of traditional clustering algorithms, cliques are not disjoint and allow genes to be assigned to multiple sets of interacting partners, consistent with biological reality. A graph is created by thresholding the correlation matrix to include only the correlations most likely to signify functional relationships. Cliques computed from the graph correspond to sets of genes for which significant edges are present between all members of the set, representing potential members of common or interacting pathways. Clique membership can be used to infer function about poorly annotated genes, based on the known functions of better-annotated genes with which they share clique membership (i.e., ''guilt-by-association''). We illustrate our method by applying it to microarray data collected from the spleens of mice exposed to low-dose ionizing radiation. Differential analysis is used to identify sets of genes whose interactions are impacted by radiation exposure. The correlation graph is also queried independently of clique to extract edges that are impacted by radiation. We present several examples of multiple gene interactions that are altered by radiation exposure and thus represent potential molecular pathways that mediate the radiation response.

  7. Extracting gene networks for low-dose radiation using graph theoretical algorithms.

    Directory of Open Access Journals (Sweden)

    Brynn H Voy

    2006-07-01

    Full Text Available Genes with common functions often exhibit correlated expression levels, which can be used to identify sets of interacting genes from microarray data. Microarrays typically measure expression across genomic space, creating a massive matrix of co-expression that must be mined to extract only the most relevant gene interactions. We describe a graph theoretical approach to extracting co-expressed sets of genes, based on the computation of cliques. Unlike the results of traditional clustering algorithms, cliques are not disjoint and allow genes to be assigned to multiple sets of interacting partners, consistent with biological reality. A graph is created by thresholding the correlation matrix to include only the correlations most likely to signify functional relationships. Cliques computed from the graph correspond to sets of genes for which significant edges are present between all members of the set, representing potential members of common or interacting pathways. Clique membership can be used to infer function about poorly annotated genes, based on the known functions of better-annotated genes with which they share clique membership (i.e., "guilt-by-association". We illustrate our method by applying it to microarray data collected from the spleens of mice exposed to low-dose ionizing radiation. Differential analysis is used to identify sets of genes whose interactions are impacted by radiation exposure. The correlation graph is also queried independently of clique to extract edges that are impacted by radiation. We present several examples of multiple gene interactions that are altered by radiation exposure and thus represent potential molecular pathways that mediate the radiation response.

  8. Low-dose extrapolation of radiation health risks: some implications of uncertainty for radiation protection at low doses.

    Science.gov (United States)

    Land, Charles E

    2009-11-01

    Ionizing radiation is a known and well-quantified human cancer risk factor, based on a remarkably consistent body of information from epidemiological studies of exposed populations. Typical examples of risk estimation include use of Japanese atomic bomb survivor data to estimate future risk from radiation-related cancer among American patients receiving multiple computed tomography scans, persons affected by radioactive fallout, or persons whose livelihoods involve some radiation exposure, such as x-ray technicians, interventional radiologists, or shipyard workers. Our estimates of radiation-related risk are uncertain, reflecting statistical variation and our imperfect understanding of crucial assumptions that must be made if we are to apply existing epidemiological data to particular situations. Fortunately, that uncertainty is also highly quantifiable, and can be presented concisely and transparently. Radiation protection is ultimately a political process that involves consent by stakeholders, a diverse group that includes people who might be expected to be risk-averse and concerned with plausible upper limits on risk (how bad could it be?), cost-averse and concerned with lower limits on risk (can you prove there is a nontrivial risk at current dose levels?), or combining both points of view. How radiation-related risk is viewed by individuals and population subgroups also depends very much on perception of related benefit, which might be (for example) medical, economic, altruistic, or nonexistent. The following presentation follows the lead of National Council on Radiation Protection and Measurements (NCRP) Commentary 14, NCRP Report 126, and later documents in treating radiation protection from the viewpoint of quantitative uncertainty analysis.

  9. 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....

  10. NAC-NOR mutations in tomato Penjar accessions attenuate multiple metabolic processes and prolong the fruit shelf life.

    Science.gov (United States)

    Kumar, Rakesh; Tamboli, Vajir; Sharma, Rameshwar; Sreelakshmi, Yellamaraju

    2018-09-01

    Several Penjar accessions of tomato grown in the Mediterranean exhibit prolonged shelf life and harbor alcobaca mutation. To uncover the metabolic basis underlying shelf life, we compared four Penjar accessions to Ailsa Craig. Three accessions bore alcobaca mutation, whereas the fourth was a novel NAC-NOR allele. Cuticle composition of Penjars varied widely during fruit ripening. All Penjars exhibited delayed ripening, prolonged on-vine and off-vine shelf life, low ethylene emission, and carotenoid levels. Metabolic profiling revealed shifts in Krebs cycle intermediates, amino acids, and γ-aminobutyric acid levels indicating the attenuation of respiration in Penjars during post-harvest storage. Penjar fruits also showed concerted downregulation of several cell-wall modifying genes and related metabolites. The high ABA and sucrose levels at the onset of senescence in Penjar fruits likely contribute to reduced water loss. Our analyses reveal that the attenuation of various metabolic processes by NAC-NOR mutation likely prolongs the shelf life of Penjar fruits. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Silibinin attenuates sulfur mustard analog-induced skin injury by targeting multiple pathways connecting oxidative stress and inflammation.

    Directory of Open Access Journals (Sweden)

    Neera Tewari-Singh

    Full Text Available Chemical warfare agent sulfur mustard (HD inflicts delayed blistering and incapacitating skin injuries. To identify effective countermeasures against HD-induced skin injuries, efficacy studies were carried out employing HD analog 2-chloroethyl ethyl sulfide (CEES-induced injury biomarkers in skin cells and SKH-1 hairless mouse skin. The data demonstrate strong therapeutic efficacy of silibinin, a natural flavanone, in attenuating CEES-induced skin injury and oxidative stress. In skin cells, silibinin (10 µM treatment 30 min after 0.35/0.5 mM CEES exposure caused a significant (p90%, and activation of transcription factors NF-κB and AP-1 (complete reversal. Similarly, silibinin treatment was also effective in attenuating CEES-induced oxidative stress measured by 4-hydroxynonenal and 5,5-dimethyl-2-(8-octanoic acid-1-pyrolline N-oxide protein adduct formation, and 8-oxo-2-deoxyguanosine levels. Since our previous studies implicated oxidative stress, in part, in CEES-induced toxic responses, the reversal of CEES-induced oxidative stress and other toxic effects by silibinin in this study indicate its pleiotropic therapeutic efficacy. Together, these findings support further optimization of silibinin in HD skin toxicity model to develop a novel effective therapy for skin injuries by vesicants.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-11-11

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

  13. 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

  14. 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.

  15. 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

  16. 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.)

  17. PET/CT in malignant melanoma: contrast-enhanced CT versus plain low-dose CT

    International Nuclear Information System (INIS)

    Pfluger, Thomas; Schneider, Vera; Fougere, Christian la; Bartenstein, Peter; Weiss, Mayo; Melzer, Henriette Ingrid; Coppenrath, Eva; Berking, Carola

    2011-01-01

    The aim of this study was to evaluate the diagnostic value of contrast-enhanced CT (CECT) versus non-enhanced low-dose CT (NECT) in the staging of advanced malignant melanoma with 18 F-fluordeoxyglucose (FDG) positron emission tomography (PET)/CT. In total, 50 18 F-FDG PET/CT examinations were performed in 50 patients with metastasized melanoma. For attenuation correction, whole-body NECT was performed followed by diagnostic CECT with contrast agent. For the whole-body PET, 18 F-FDG was applied. Criteria for evaluation were signs of vital tumour tissue (extent of lesions, contrast enhancement, maximum standardized uptake value >2.5). Findings suspicious for melanoma were considered lesions. NECT, CECT and 18 F-FDG PET were evaluated separately, followed by combined analysis of PET/NECT and PET/CECT. Findings were verified histologically and/or by follow-up (>6 months). Overall, 232 lesions were analysed, and 151 proved to be metastases. The sensitivity of NECT, CECT, PET, PET/NECT and PET/CECT was 62, 85, 90, 97 and 100%, and specificity was 52, 63, 88, 93 and 93%, respectively. Compared to CECT, NECT obtained additional false-negative results: lymph node (n = 19) and liver/spleen metastases (n = 9). Misinterpreted physiological structures mainly caused additional false-positive findings (n = 17). In combined analysis of PET/NECT, six false-positive [other tumours (n = 2), inflammatory lymph nodes (n = 2), inflammatory lung lesion (n = 1), blood vessel (n = 1)] and five false-negative findings [liver (n = 3), spleen (n = 1), lymph node metastases (n = 1)] remained. On PET/CECT, six false-positive [inflammatory lymph nodes (n = 3), other tumours (n = 2), inflammatory lung lesion (n = 1)] and no false-negative findings occurred. However, additional false findings on PET/NECT (6 of 232) did not change staging compared to PET/CECT. Our results indicate that it is justified to perform PET/NECT instead of PET/CECT for melanoma staging. (orig.)

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

    International Nuclear Information System (INIS)

    Lee, S.K.

    1998-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Feinendegen, L.E

    2003-07-01

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

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

    International Nuclear Information System (INIS)

    Feinendegen, L.E.

    2003-01-01

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

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

    International Nuclear Information System (INIS)

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

    1999-01-01

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

  2. Low-dose aspartame consumption differentially affects gut microbiota-host metabolic interactions in the diet-induced obese rat.

    Directory of Open Access Journals (Sweden)

    Marie S A Palmnäs

    Full Text Available Aspartame consumption is implicated in the development of obesity and metabolic disease despite the intention of limiting caloric intake. The mechanisms responsible for this association remain unclear, but may involve circulating metabolites and the gut microbiota. Aims were to examine the impact of chronic low-dose aspartame consumption on anthropometric, metabolic and microbial parameters in a diet-induced obese model. Male Sprague-Dawley rats were randomized into a standard chow diet (CH, 12% kcal fat or high fat (HF, 60% kcal fat and further into ad libitum water control (W or low-dose aspartame (A, 5-7 mg/kg/d in drinking water treatments for 8 week (n = 10-12 animals/treatment. Animals on aspartame consumed fewer calories, gained less weight and had a more favorable body composition when challenged with HF compared to animals consuming water. Despite this, aspartame elevated fasting glucose levels and an insulin tolerance test showed aspartame to impair insulin-stimulated glucose disposal in both CH and HF, independently of body composition. Fecal analysis of gut bacterial composition showed aspartame to increase total bacteria, the abundance of Enterobacteriaceae and Clostridium leptum. An interaction between HF and aspartame was also observed for Roseburia ssp wherein HF-A was higher than HF-W (P<0.05. Within HF, aspartame attenuated the typical HF-induced increase in the Firmicutes:Bacteroidetes ratio. Serum metabolomics analysis revealed aspartame to be rapidly metabolized and to be associated with elevations in the short chain fatty acid propionate, a bacterial end product and highly gluconeogenic substrate, potentially explaining its negative affects on insulin tolerance. How aspartame influences gut microbial composition and the implications of these changes on the development of metabolic disease require further investigation.

  3. Low-dose aspartame consumption differentially affects gut microbiota-host metabolic interactions in the diet-induced obese rat.

    Science.gov (United States)

    Palmnäs, Marie S A; Cowan, Theresa E; Bomhof, Marc R; Su, Juliet; Reimer, Raylene A; Vogel, Hans J; Hittel, Dustin S; Shearer, Jane

    2014-01-01

    Aspartame consumption is implicated in the development of obesity and metabolic disease despite the intention of limiting caloric intake. The mechanisms responsible for this association remain unclear, but may involve circulating metabolites and the gut microbiota. Aims were to examine the impact of chronic low-dose aspartame consumption on anthropometric, metabolic and microbial parameters in a diet-induced obese model. Male Sprague-Dawley rats were randomized into a standard chow diet (CH, 12% kcal fat) or high fat (HF, 60% kcal fat) and further into ad libitum water control (W) or low-dose aspartame (A, 5-7 mg/kg/d in drinking water) treatments for 8 week (n = 10-12 animals/treatment). Animals on aspartame consumed fewer calories, gained less weight and had a more favorable body composition when challenged with HF compared to animals consuming water. Despite this, aspartame elevated fasting glucose levels and an insulin tolerance test showed aspartame to impair insulin-stimulated glucose disposal in both CH and HF, independently of body composition. Fecal analysis of gut bacterial composition showed aspartame to increase total bacteria, the abundance of Enterobacteriaceae and Clostridium leptum. An interaction between HF and aspartame was also observed for Roseburia ssp wherein HF-A was higher than HF-W (Paspartame attenuated the typical HF-induced increase in the Firmicutes:Bacteroidetes ratio. Serum metabolomics analysis revealed aspartame to be rapidly metabolized and to be associated with elevations in the short chain fatty acid propionate, a bacterial end product and highly gluconeogenic substrate, potentially explaining its negative affects on insulin tolerance. How aspartame influences gut microbial composition and the implications of these changes on the development of metabolic disease require further investigation.

  4. Optimization of SPECT-CT Hybrid Imaging Using Iterative Image Reconstruction for Low-Dose CT: A Phantom Study.

    Directory of Open Access Journals (Sweden)

    Oliver S Grosser

    Full Text Available Hybrid imaging combines nuclear medicine imaging such as single photon emission computed tomography (SPECT or positron emission tomography (PET with computed tomography (CT. Through this hybrid design, scanned patients accumulate radiation exposure from both applications. Imaging modalities have been the subject of long-term optimization efforts, focusing on diagnostic applications. It was the aim of this study to investigate the influence of an iterative CT image reconstruction algorithm (ASIR on the image quality of the low-dose CT images.Examinations were performed with a SPECT-CT scanner with standardized CT and SPECT-phantom geometries and CT protocols with systematically reduced X-ray tube currents. Analyses included image quality with respect to photon flux. Results were compared to the standard FBP reconstructed images. The general impact of the CT-based attenuation maps used during SPECT reconstruction was examined for two SPECT phantoms. Using ASIR for image reconstructions, image noise was reduced compared to FBP reconstructions for the same X-ray tube current. The Hounsfield unit (HU values reconstructed by ASIR were correlated to the FBP HU values(R2 ≥ 0.88 and the contrast-to-noise ratio (CNR was improved by ASIR. However, for a phantom with increased attenuation, the HU values shifted for low X-ray tube currents I ≤ 60 mA (p ≤ 0.04. In addition, the shift of the HU values was observed within the attenuation corrected SPECT images for very low X-ray tube currents (I ≤ 20 mA, p ≤ 0.001.In general, the decrease in X-ray tube current up to 30 mA in combination with ASIR led to a reduction of CT-related radiation exposure without a significant decrease in image quality.

  5. 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.

  6. 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.)

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Physics and quality assurance for brachytherapy - Part II: Low dose rate and pulsed dose rate

    International Nuclear Information System (INIS)

    Williamson, Jeffrey F.

    1997-01-01

    Purpose: A number of recent developments have revitalized brachytherapy including remote afterloading, implant optimization, increasing use of 3D imaging, and advances in dose specification and basic dosimetry. However, the core physical principles underlying the classical methods of dose calculation and arrangement of multiple sources remain unchanged. The purpose of this course is to review these principles and their applications to low dose-rate interstitial and intracavitary brachytherapy. Emphasis will be placed upon the classical implant systems along with classical and modern methods of dose specification. The level of presentation is designed for radiation oncology residents and beginning clinical physicists. A. Basic Principles (1) Radium-substitute vs. low-energy sealed sources (2) Dose calculation principles (3) The mysteries of source strength specification revealed: mgRaEq, mCi and air-kerma strength B. Interstitial Brachytherapy (1) Target volume, implanted volume, dose specification in implants and implant optimization criteria (2) Classical implant systems: Manchester Quimby and Paris a) Application of the Manchester system to modern brachytherapy b) Comparison of classical systems (3) Permanent interstitial implants a) Photon energy and half life b) Dose specification and pre-operative planning (4) The alphabet soup of dose specification: MCD (mean central dose), minimum dose, MPD (matched peripheral dose), MPD' (minimum peripheral dose) and DVH (dose-volume histogram) quality indices C. Intracavitary Brachytherapy for Carcinoma of the Cervix (1) Basic principles a) Manchester System: historical foundation of U.S. practice patterns b) Principles of applicator design (2) Dose specification and treatment prescription a) mg-hrs, reference points, ICRU Report 38 reference volume -- Point A dose vs mg-hrs and IRAK (Integrated Reference Air Kerma) -- Tissue volume treated vs mg-hrs and IRAK b) Practical methods of treatment specification and prescription

  13. Radiation induced bystander effects: mechanisms and implication for low dose radiation risk assessment

    International Nuclear Information System (INIS)

    Hei, T.L.; Randers-Pehrson, G.; Zhou, H.

    2003-01-01

    Using a precision microbeam to target an exact fraction of cells in a population and irradiated their nuclei with exactly one alpha particle each, we found that the frequencies of induced mutations and chromosomal changes in populations where some known fractions of nuclei were hit are consistent with non-hit cells contributing significantly to the response. In fact, irradiation of 10% of a mammalian cell population with a single alpha particle per cell results in a mutant yield similar to that observed when all of the cells in the population are irradiated. Although the bystander observations have been well established, the underlying mechanism(s) remain largely unknown. There are indications that multiple pathways are involved in the bystander phenomenon and different cell types respond differently to the bystander signaling. In confluent monolayers, there is evident that gap junctional communication is crucial in mediating the bystander effect whereas reactive oxygen and reactive nitrogen species have been implicated as the mediating molecules in sub-confluent cultures. Although p53 is not necessary for the expression of bystander effect, there is evident that repair deficient cells may express a higher bystander response. Using cDNA microarrays, a number of cellular signaling genes have been shown to be differentially expressed among bystander cells. The functional roles of these genes in the bystander effect will be discussed. The bystander observations imply that the relevant target for various radiobiological endpoints is larger than an individual cell and suggest a need to reconsider the validity of the linear extrapolation in making risk estimate for low dose radiation exposure. (Work supported by NIH grants CA 49062 and CA-RR11623)

  14. Physics and quality assurance for brachytherapy - Part II: Low dose rate and pulsed dose rate

    International Nuclear Information System (INIS)

    Williamson, Jeffrey F.

    1996-01-01

    Purpose: A number of recent developments have revitalized brachytherapy including remote afterloading, implant optimization, increasing use of 3D imaging, and advances in dose specification and basic dosimetry. However, the core physical principles underlying the classical methods of dose calculation and arrangement of multiple sources remain unchanged. The purpose of this course is to review these principles and their applications to low dose-rate interstitial and intracavitary brachytherapy. Emphasis will be placed upon the classical implant systems along with classical and modern methods of dose specification. The level of presentation is designed for radiation oncology residents and beginning clinical physicists. A. Basic Principles (1) Radium-substitute vs. low-energy sealed sources (2) Dose calculation principles (3) The mysteries of source strength specification revealed: mgRaEq, mCi and air-kerma strength B. Interstitial Brachytherapy (1) Target volume, implanted volume, dose specification in implants and implant optimization criteria (2) Classical implant systems: Manchester Quimby and Paris a) Application of the Manchester system to modern brachytherapy b) Comparison of classical systems (3) Permanent interstitial implants a) Photon energy and half life b) Dose specification and pre-operative planning (4) The alphabet soup of dose specification: MCD (mean central dose), minimum dose, MPD (matched peripheral dose), MPD' (minimum peripheral dose) and DVH (dose-volume histogram) quality indices C. Intracavitary Brachytherapy for Carcinoma of the Cervix (1) Basic principles a) Manchester System: historical foundation of U.S. practice patterns b) Principles of applicator design (2) Dose specification and treatment prescription a) mg-hrs, reference points, ICRU Report 38 reference volume --Point A dose vs mg-hrs and IRAK (Integrated Reference Air Kerma) --Tissue volume treated vs mg-hrs and IRAK b) Practical methods of treatment specification and prescription

  15. 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

  16. 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.

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

    DEFF Research Database (Denmark)

    Skriver, Charlotte; Dehlendorff, Christian; Borre, Michael

    2016-01-01

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

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

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

    International Nuclear Information System (INIS)

    2007-01-01

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

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

    International Nuclear Information System (INIS)

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

    2005-01-01

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

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

    International Nuclear Information System (INIS)

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

    1980-01-01

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

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

    International Nuclear Information System (INIS)

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

    1998-01-01

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

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

    International Nuclear Information System (INIS)

    Ehjdus, L.Kh.

    1996-01-01

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

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

    Science.gov (United States)

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

    2010-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-07-01

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

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

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

    International Nuclear Information System (INIS)

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

    2011-01-01

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

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

    International Nuclear Information System (INIS)

    Iyer, G.K.

    1993-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-12-31

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

  10. Estimation of the total effective dose from low-dose CT scans and radiopharmaceutical administrations delivered to patients undergoing SPECT/CT explorations

    International Nuclear Information System (INIS)

    Montes, C.; Hernandez, J.; Gomez-Caminero, F.; Garcia, S.; Martin, C.; Rosero, A.; Tamayo, P.

    2013-01-01

    Hybrid imaging, such as single photon emission computed tomography (SPECT)/CT, is used in routine clinical practice, allowing coregistered images of the functional and structural information provided by the two imaging modalities. However, this multimodality imaging may mean that patients are exposed to a higher radiation dose than those receiving SPECT alone. The study aimed to determine the radiation exposure of patients who had undergone SPECT/CT examinations and to relate this to the Background Equivalent Radiation Time (BERT). 145 SPECT/CT studies were used to estimate the total effective dose to patients due to both radiopharmaceutical administrations and low-dose CT scans. The CT contribution was estimated by the Dose-Length Product method. Specific conversion coefficients were calculated for SPECT explorations. The radiation dose from low-dose CTs ranged between 0.6 mSv for head and neck CT and 2.6 mSv for whole body CT scan, representing a maximum of 1 year of background radiation exposure. These values represent a decrease of 80-85% with respect to the radiation dose from diagnostic CT. The radiation exposure from radiopharmaceutical administration varied from 2.1 mSv for stress myocardial perfusion SPECT to 26 mSv for gallium SPECT in patients with lymphoma. The BERT ranged from 1 to 11 years. The contribution of low-dose CT scans to the total radiation dose to patients undergoing SPECT/CT examinations is relatively low compared with the effective dose from radiopharmaceutical administration. When a CT scan is only acquired for anatomical localization and attenuation correction, low-dose CT scan is justified on the basis of its lower dose. (author)

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

    Science.gov (United States)

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

    2017-11-28

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-05-15

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

  13. 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.

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

    International Nuclear Information System (INIS)

    Fabry, L.

    1982-01-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    International Nuclear Information System (INIS)

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

    1995-01-01

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

  17. 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.

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

    DEFF Research Database (Denmark)

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

    2017-01-01

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

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

    DEFF Research Database (Denmark)

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

    2017-01-01

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

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

    Directory of Open Access Journals (Sweden)

    José Arturo Bríñez-Horta

    2011-09-01

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

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

    International Nuclear Information System (INIS)

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

    1991-01-01

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

  2. 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

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

    International Nuclear Information System (INIS)

    Skov, K.A.

    1992-01-01

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

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

    International Nuclear Information System (INIS)

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

    1997-01-01

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

  5. Synthetic CT: Simulating low dose single and dual energy protocols from a dual energy scan

    International Nuclear Information System (INIS)

    Wang, Adam S.; Pelc, Norbert J.

    2011-01-01

    Purpose: The choice of CT protocol can greatly impact patient dose and image quality. Since acquiring multiple scans at different techniques on a given patient is undesirable, the ability to predict image quality changes starting from a high quality exam can be quite useful. While existing methods allow one to generate simulated images of lower exposure (mAs) from an acquired CT exam, the authors present and validate a new method called synthetic CT that can generate realistic images of a patient at arbitrary low dose protocols (kVp, mAs, and filtration) for both single and dual energy scans. Methods: The synthetic CT algorithm is derived by carefully ensuring that the expected signal and noise are accurate for the simulated protocol. The method relies on the observation that the material decomposition from a dual energy CT scan allows the transmission of an arbitrary spectrum to be predicted. It requires an initial dual energy scan of the patient to either synthesize raw projections of a single energy scan or synthesize the material decompositions of a dual energy scan. The initial dual energy scan contributes inherent noise to the synthesized projections that must be accounted for before adding more noise to simulate low dose protocols. Therefore, synthetic CT is subject to the constraint that the synthesized data have noise greater than the inherent noise. The authors experimentally validated the synthetic CT algorithm across a range of protocols using a dual energy scan of an acrylic phantom with solutions of different iodine concentrations. An initial 80/140 kVp dual energy scan of the phantom provided the material decomposition necessary to synthesize images at 100 kVp and at 120 kVp, across a range of mAs values. They compared these synthesized single energy scans of the phantom to actual scans at the same protocols. Furthermore, material decompositions of a 100/120 kVp dual energy scan are synthesized by adding correlated noise to the initial material

  6. Low-dose/dose-rate γ radiation depresses neural differentiation and alters protein expression profiles in neuroblastoma SH-SY5Y cells and C17.2 neural stem cells.

    Science.gov (United States)

    Bajinskis, Ainars; Lindegren, Heléne; Johansson, Lotta; Harms-Ringdahl, Mats; Forsby, Anna

    2011-02-01

    The effects of low doses of ionizing radiation on cellular development in the nervous system are presently unclear. The focus of the present study was to examine low-dose γ-radiation-induced effects on the differentiation of neuronal cells and on the development of neural stem cells to glial cells. Human neuroblastoma SH-SY5Y cells were exposed to (137)Cs γ rays at different stages of retinoic acid-induced neuronal differentiation, and neurite formation was determined 6 days after exposure. When SH-SY5Y cells were exposed to low-dose-rate γ rays at the onset of differentiation, the number of neurites formed per cell was significantly less after exposure to either 10, 30 or 100 mGy compared to control cells. Exposure to 10 and 30 mGy attenuated differentiation of immature C17.2 mouse-derived neural stem cells to glial cells, as verified by the diminished expression of glial fibrillary acidic protein. Proteomic analysis of the neuroblastoma cells by 2D-PAGE after 30 mGy irradiation showed that proteins involved in neuronal development were downregulated. Proteins involved in cell cycle and proliferation were altered in both cell lines after exposure to 30 mGy; however, the rate of cell proliferation was not affected in the low-dose range. The radiation-induced attenuation of differentiation and the persistent changes in protein expression is indicative of an epigenetic rather than a cytotoxic mechanism.

  7. TU-H-207A-08: Estimating Radiation Dose From Low-Dose Lung Cancer Screening CT Exams Using Tube Current Modulation

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, A; Bostani, M [University of California, Los Angeles, Los Angeles, CA (United States); McMillan, K [Mayo Clinic, Rochester, MN (United States); Zankl, M [Helmholtz Zentrum Munchen, Neuherberg (Germany); Cagnon, C [UCLA Medical Center, Los Angeles, CA (United States); McNitt-Gray, M [UCLA School of Medicine, Los Angeles, CA (United States)

    2016-06-15

    Purpose: The purpose of this work is to estimate effective and lung doses from a low-dose lung cancer screening CT protocol using Tube Current Modulation (TCM) across patient models of different sizes. Methods: Monte Carlo simulation methods were used to estimate effective and lung doses from a low-dose lung cancer screening protocol for a 64-slice CT (Sensation 64, Siemens Healthcare) that used TCM. Scanning parameters were from the AAPM protocols. Ten GSF voxelized patient models were used and had all radiosensitive organs identified to facilitate estimating both organ and effective doses. Predicted TCM schemes for each patient model were generated using a validated method wherein tissue attenuation characteristics and scanner limitations were used to determine the TCM output as a function of table position and source angle. The water equivalent diameter (WED) was determined by estimating the attenuation at the center of the scan volume for each patient model. Monte Carlo simulations were performed using the unique TCM scheme for each patient model. Lung doses were tallied and effective doses were estimated using ICRP 103 tissue weighting factors. Effective and lung dose values were normalized by scanspecific 32 cm CTDIvol values based upon the average tube current across the entire simulated scan. Absolute and normalized doses were reported as a function of WED for each patient. Results: For all ten patients modeled, the effective dose using TCM protocols was below 1.5 mSv. Smaller sized patient models experienced lower absolute doses compared to larger sized patients. Normalized effective and lung doses showed some dependence on patient size (R2 = 0.77 and 0.78, respectively). Conclusion: Effective doses for a low-dose lung screening protocol using TCM were below 1.5 mSv for all patient models used in this study. Institutional research agreement, Siemens Healthcare; Past recipient, research grant support, Siemens Healthcare; Consultant, Toshiba America Medical

  8. TU-H-207A-08: Estimating Radiation Dose From Low-Dose Lung Cancer Screening CT Exams Using Tube Current Modulation

    International Nuclear Information System (INIS)

    Hardy, A; Bostani, M; McMillan, K; Zankl, M; Cagnon, C; McNitt-Gray, M

    2016-01-01

    Purpose: The purpose of this work is to estimate effective and lung doses from a low-dose lung cancer screening CT protocol using Tube Current Modulation (TCM) across patient models of different sizes. Methods: Monte Carlo simulation methods were used to estimate effective and lung doses from a low-dose lung cancer screening protocol for a 64-slice CT (Sensation 64, Siemens Healthcare) that used TCM. Scanning parameters were from the AAPM protocols. Ten GSF voxelized patient models were used and had all radiosensitive organs identified to facilitate estimating both organ and effective doses. Predicted TCM schemes for each patient model were generated using a validated method wherein tissue attenuation characteristics and scanner limitations were used to determine the TCM output as a function of table position and source angle. The water equivalent diameter (WED) was determined by estimating the attenuation at the center of the scan volume for each patient model. Monte Carlo simulations were performed using the unique TCM scheme for each patient model. Lung doses were tallied and effective doses were estimated using ICRP 103 tissue weighting factors. Effective and lung dose values were normalized by scanspecific 32 cm CTDIvol values based upon the average tube current across the entire simulated scan. Absolute and normalized doses were reported as a function of WED for each patient. Results: For all ten patients modeled, the effective dose using TCM protocols was below 1.5 mSv. Smaller sized patient models experienced lower absolute doses compared to larger sized patients. Normalized effective and lung doses showed some dependence on patient size (R2 = 0.77 and 0.78, respectively). Conclusion: Effective doses for a low-dose lung screening protocol using TCM were below 1.5 mSv for all patient models used in this study. Institutional research agreement, Siemens Healthcare; Past recipient, research grant support, Siemens Healthcare; Consultant, Toshiba America Medical

  9. 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.

  10. Low-Dose Ethanol Preconditioning Protects Against Oxygen-Glucose Deprivation/Reoxygenation-Induced Neuronal Injury By Activating Large Conductance, Ca2+-Activated K+ Channels In Vitro

    Institute of Scientific and Technical Information of China (English)

    Fang Su; An-Chen Guo; Wei-Wei Li; Yi-Long Zhao; Zheng-Yi Qu; Yong-Jun Wang; Qun Wang; Yu-Lan Zhu

    2017-01-01

    Increasing evidence suggests that low to moderate ethanol ingestion protects against the deleterious effects of subsequent ischemia/reperfusion;however,the underlying mechanism has not been elucidated.In the present study,we showed that expression of the neuronal large-conductance,Ca2+-activated K+ channel (BKCa) α-subunit was upregulated in cultured neurons exposed to oxygen-glucose deprivatior/reoxygenation (OGD/R) compared with controls.Preconditioning with low-dose ethanol (10 mmol/L) increased cell survival rate in neurons subjected to OGD/R,attenuated the OGD/R-induced elevation of cytosolic Ca2+ levels,and reduced the number of apoptotic neurons.Western blots revealed that ethanol preconditioning upregulated expression of the anti-apoptotic protein Bcl-2 and downregulated the pro-apoptotic protein Bax.The protective effect of ethanol preconditioning was antagonized by a BKCa channel inhibitor,paxilline.Inside-out patches in primary neurons also demonstrated the direct activation of the BKCa channel by 10 mmol/L ethanol.The above results indicated that low-dose ethanol preconditioning exerts its neuroprotective effects by attenuating the elevation of cytosolic Ca2+ and preventing neuronal apoptosis,and this is mediated by BKCa channel activation.

  11. Low-Dose Ethanol Preconditioning Protects Against Oxygen-Glucose Deprivation/Reoxygenation-Induced Neuronal Injury By Activating Large Conductance, Ca2+-Activated K+ Channels In Vitro.

    Science.gov (United States)

    Su, Fang; Guo, An-Chen; Li, Wei-Wei; Zhao, Yi-Long; Qu, Zheng-Yi; Wang, Yong-Jun; Wang, Qun; Zhu, Yu-Lan

    2017-02-01

    Increasing evidence suggests that low to moderate ethanol ingestion protects against the deleterious effects of subsequent ischemia/reperfusion; however, the underlying mechanism has not been elucidated. In the present study, we showed that expression of the neuronal large-conductance, Ca 2+ -activated K + channel (BK Ca ) α-subunit was upregulated in cultured neurons exposed to oxygen-glucose deprivation/reoxygenation (OGD/R) compared with controls. Preconditioning with low-dose ethanol (10 mmol/L) increased cell survival rate in neurons subjected to OGD/R, attenuated the OGD/R-induced elevation of cytosolic Ca 2+ levels, and reduced the number of apoptotic neurons. Western blots revealed that ethanol preconditioning upregulated expression of the anti-apoptotic protein Bcl-2 and downregulated the pro-apoptotic protein Bax. The protective effect of ethanol preconditioning was antagonized by a BK Ca channel inhibitor, paxilline. Inside-out patches in primary neurons also demonstrated the direct activation of the BK Ca channel by 10 mmol/L ethanol. The above results indicated that low-dose ethanol preconditioning exerts its neuroprotective effects by attenuating the elevation of cytosolic Ca 2+ and preventing neuronal apoptosis, and this is mediated by BK Ca channel activation.

  12. PDGFRα depletion attenuates glioblastoma stem cells features by modulation of STAT3, RB1 and multiple oncogenic signals.

    Science.gov (United States)

    Cenciarelli, Carlo; Marei, Hany E; Felsani, Armando; Casalbore, Patrizia; Sica, Gigliola; Puglisi, Maria Ausiliatrice; Cameron, Angus J M; Olivi, Alessandro; Mangiola, Annunziato

    2016-08-16

    Platelet derived growth factor receptors (PDGFRs) play an important role in tumor pathogenesis, and they are frequently overexpressed in glioblastoma (GBM). Earlier we have shown a higher protein expression of PDGFR isoforms (α and β) in peritumoral-tissue derived cancer stem cells (p-CSC) than in tumor core (c-CSC) of several GBM affected patients. In the current study, in order to assess the activity of PDGFRα/PDGF-AA signaling axis, we performed time course experiments to monitor the effects of exogenous PDGF-AA on the expression of downstream target genes in c-CSC vs p-CSC. Interestingly, in p-CSC we detected the upregulation of Y705-phosphorylated Stat3, concurrent with a decrement of Rb1 protein in its active state, within minutes of PDGF-AA addition. This finding prompted us to elucidate the role of PDGFRα in self-renewal, invasion and differentiation in p-CSC by using short hairpin RNA depletion of PDGFRα expression. Notably, in PDGFRα-depleted cells, protein analysis revealed attenuation of stemness-related and glial markers expression, alongside early activation of the neuronal marker MAP2a/b that correlated with the induction of tumor suppressor Rb1. The in vitro reduction of the invasive capacity of PDGFRα-depleted CSC as compared to parental cells correlated with the downmodulation of markers of epithelial-mesenchymal transition phenotype and angiogenesis. Surprisingly, we observed the induction of anti-apoptotic proteins and compensatory oncogenic signals such as EDN1, EDNRB, PRKCB1, PDGF-C and PDGF-D. To conclude, we hypothesize that the newly discovered PDGFRα/Stat3/Rb1 regulatory axis might represent a potential therapeutic target for GBM treatment.

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

    Science.gov (United States)

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

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

    NARCIS (Netherlands)

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

    2014-01-01

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

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

    International Nuclear Information System (INIS)

    Czihak, G.K.

    1991-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-09-15

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

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1987-09-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Azzam, Edouard I

    2013-01-16

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

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

    NARCIS (Netherlands)

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

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

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

    African Journals Online (AJOL)

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

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

    African Journals Online (AJOL)

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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2016-02-01

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

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

    International Nuclear Information System (INIS)

    1997-11-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-11-01

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

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

    NARCIS (Netherlands)

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

    1996-01-01

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

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

    International Nuclear Information System (INIS)

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

    2000-01-01

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

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

    Science.gov (United States)

    Badretale, S.; Sh