scholarly journals Requirements for Identification of Low Dose and Non-Linear Mutagenic Responses to Ionising Radiation

Dose-Response ◽  
2007 ◽  
Vol 5 (4) ◽  
pp. dose-response.0 ◽  
Author(s):  
Pamela J. Sykes ◽  
Tanya K. Day
Keyword(s):  
Low Dose ◽  
Threshold Model ◽  
Dose Range ◽  
Cellular Transformation ◽  
Low Dose Radiation ◽  
Spontaneous Frequency ◽  
High Doses ◽  
Dose Radiation

Cancer results from multiple changes in gene expression that can occur both genetically and epigenetically. High doses of radiation can lead to mutations and cancer. At high doses the number of mutations caused by radiation is essentially linear with dose. Low dose radiation induced protective responses observed for cancer in vivo and cellular transformation in vitro would predict that hormetic responses would also be observed in mutation assays. Although there are a large number of different mutation assays available, very few are able to detect changes in mutation frequency in response to very low doses of DNA damaging agents. The easiest way to cope with this lack of data in the low dose range is to invoke a linear-no-threshold model for risk assessment. The reasons for the lack of data are discussed. In order to identify hormetic mutation responses, assays need to have a spontaneous frequency that is high enough to enable a reduction below spontaneous frequency to be detected in a feasible number of scored cells and also need to be able to identify both genetic and epigenetic changes. The pKZ1 chromosomal inversion assay fits the criteria for detecting hormetic responses to low dose radiation.

scholarly journals Low-dose radiation therapy: a treatment for pneumonia resulting from COVID-19

2021 ◽  
pp. 1-4
Author(s):  
Hamid Ghaznavi ◽  
Farideh Elahimanesh ◽  
Jamil Abdolmohammadi ◽  
Meysam Mirzaie ◽  
Sadegh Ghaderi
Keyword(s):  
Lung Cancer ◽  
Radiation Therapy ◽  
Low Dose ◽  
Distress Syndrome ◽  
Lung Cancer Risk ◽  
Low Dose Radiation ◽  
The World ◽  
Dose Radiation

Abstract Background: The Coronavirus disease 2019 (COVID-19) is spreading rapidly throughout the world. Lung is the primary organ which the COVID-19 virus affects and leads to pneumonia, an acute respiratory distress syndrome. COVID-19 infects the lower respiratory system, and the lung’s response to this infection is recruiting macrophages and monocytes leading to inflammation, this response causes widespread damage to the lung’s airways. Aim: The purpose of this study is to review studies of using low-dose radiation as a treatment for the inflammation of the tissue and pneumonia resulting from COVID-19. These studies were compared with the risk of developing lung cancer during performed dose for the treatment of COVID-19 in radiation therapy. Materials and methods: Our study focused on in vitro, in vivo and clinical reports of using low-dose radiation for the treatment of inflammation, pneumonia and COVID-19. The risk of lung cancer resulting from suggested dose in these studies was also evaluated. Conclusion: From the review of articles, we have found that low-dose radiation can lead to improvement in inflammation in different line cells and animals; in addition, it has been effective in treating inflammation and pneumonia caused by COVID-19 in human up to 80%. Since suggested doses do not remarkably increase the lung cancer risk, low-dose radiation can be an adjuvant treatment for COVID-19 patients.

scholarly journals Injectable Hydrogel for Synergetic Low Dose Radiotherapy, Chemodynamic Therapy and Photothermal Therapy

2021 ◽  
Vol 9 ◽  
Author(s):  
Mingzhu Chen ◽  
Ziqi Wang ◽  
Weilong Suo ◽  
Zhirong Bao ◽  
Hong Quan
Keyword(s):  
Photothermal Therapy ◽  
Low Dose ◽  
Tumor Therapy ◽  
Intratumoral Injection ◽  
Low Dose Radiation ◽  
Injectable Hydrogel ◽  
Low Dose Radiotherapy ◽  
Dose Radiation

Higher doses of radiotherapy (RT) are associated with resistance induction, therefore highly selective and controllable radiosensitizers are urgently needed. To address this issue, we developed a FeGA-based injectable hydrogel system (FH) that can be used in combination with low-dose radiation. Our FH can deliver FeGA directly to the tumor site via intratumoral injection, where it is a reservoir-based system to conserve FeGA. The photothermal properties of FeGA steadily dissolve FH under laser irradiation, and, simultaneously, FeGA reacts with a large amount of H2O2 in the cell to produce OH (Fenton reaction) which is highly toxic to mitochondria, rendering the cell inactive and reducing radiotherapy resistance. In vivo and in vitro studies suggest that combining the FH and NIR irradiation with RT (2Gy) can significantly reduce tumor proliferation without side effects such as inflammation. To conclude, this is the first study to achieve combined chemodynamic therapy (CDT) and photothermal therapy (PTT) in situ treatment, and the best therapeutic effect can be obtained with a low-dose radiation combination, thus expanding the prospects of FeGA-based tumor therapy.

scholarly journals Low-Dose Radiation Induces Adaptive Response in Normal Cells, but not in Tumor Cells: In vitro and in vivo Studies

2008 ◽  
Vol 49 (3) ◽  
pp. 219-230 ◽  
Author(s):  
Hongyu JIANG ◽  
Wei LI ◽  
Xiuyi LI ◽  
Lu CAI ◽  
Guanjun WANG
Keyword(s):  
Tumor Cells ◽  
Adaptive Response ◽  
Low Dose ◽  
In Vivo Studies ◽  
Low Dose Radiation ◽  
Normal Cells ◽  
Dose Radiation

scholarly journals Toll-Like Receptor Signaling in Airborne Burkholderia thailandensis Infection

2009 ◽  
Vol 77 (12) ◽  
pp. 5612-5622 ◽  
Author(s):  
T. Eoin West ◽  
Thomas R. Hawn ◽  
Shawn J. Skerrett
Keyword(s):  
Low Dose ◽  
Inflammatory Responses ◽  
High Dose ◽  
Tlr Signaling ◽  
Necrosis Factor Alpha ◽  
Airborne Infection ◽  
Essential Components ◽  
High Doses

ABSTRACT Melioidosis is a tropical disease endemic in southeast Asia and northern Australia caused by the gram-negative soil saprophyte Burkholderia pseudomallei. Although infection is often systemic, the lung is frequently involved. B. thailandensis is a closely related organism that at high doses causes lethal pneumonia in mice. We examined the role of Toll-like receptors (TLRs), essential components of innate immunity, in vitro and in vivo during murine B. thailandensis pneumonia. TLR2, TLR4, and TLR5 mediate NF-κB activation by B. thailandensis in transfected HEK293 or CHO cells. In macrophages, TLR4 and the adaptor molecule MyD88, but not TLR2 or TLR5, are required for tumor necrosis factor alpha production induced by B. thailandensis. In low-dose airborne infection, TLR4 is needed for early, but not late, bacterial containment, and MyD88 is essential for control of infection and host survival. TLR2 and TLR5 are not necessary to contain low-dose infection. In high-dose airborne infection, TLR2 deficiency confers a slight survival advantage. Lung and systemic inflammatory responses are induced by low-dose inhaled B. thailandensis independently of individual TLRs or MyD88. These findings suggest that redundancy in TLR signaling or other MyD88-dependent pathways may be important in pneumonic B. thailandensis infection but that MyD88-independent mechanisms of inflammation are also activated. TLR signaling in B. thailandensis infection is substantially comparable to signaling induced by virulent B. pseudomallei. These studies provide additional insights into the host-pathogen interaction in pneumonic Burkholderia infection.

scholarly journals First Insights into the Effect of Low-Dose X-Ray Irradiation in Adipose-Derived Stem Cells

2019 ◽  
Vol 20 (23) ◽  
pp. 6075 ◽  
Author(s):  
Annemarie Schröder ◽  
Stephan Kriesen ◽  
Guido Hildebrandt ◽  
Katrin Manda
Keyword(s):  
Stem Cells ◽  
Low Dose ◽  
Dose Range ◽  
Adipose Derived Stem Cells ◽  
Long Term Effects ◽  
Low Dose Radiation ◽  
Term Survival ◽  
Cell Therapies ◽  
Dose Radiation

(1) Background: Emerging interest of physicians to use adipose-derived stem cells (ADSCs) for regenerative therapies and the fact that low-dose irradiation (LD-IR ≤ 0.1 Gy) has been reported to enhance the proliferation of several human normal and bone-marrow stem cells, but not that of tumor cells, lead to the idea of improving stem cell therapies via low-dose radiation. Therefore, the aim of this study was to investigate unwanted side effects, as well as proliferation-stimulating mechanisms of LD-IR on ADSCs. (2) Methods: To avoid donor specific effects, ADSCs isolated from mamma reductions of 10 donors were pooled and used for the radiobiological analysis. The clonogenic survival assay was used to classify the long-term effects of low-dose radiation in ADSCs. Afterwards, cytotoxicity and genotoxicity, as well as the effect of irradiation on proliferation of ADSCs were investigated. (3) Results: LD (≤ 0.1 Gy) of ionizing radiation promoted the proliferation and survival of ADSCs. Within this dose range neither geno- nor cytotoxic effects were detectable. In contrast, greater doses within the dose range of >0.1–2.0 Gy induced residual double-strand breaks and reduced the long-term survival, as well as the proliferation rate of ADSCs. (4) Conclusions: Our data suggest that ADSCs are resistant to LD-IR. Furthermore, LD-IR could be a possible mediator to improve approaches of stem cells in the field of regenerative medicine.

scholarly journals Radiophobia: 7 Reasons Why Radiography Used in Spine and Posture Rehabilitation Should Not Be Feared or Avoided

Dose-Response ◽  
2018 ◽  
Vol 16 (2) ◽  
pp. 155932581878144 ◽  
Author(s):  
Paul A. Oakley ◽  
Deed E. Harrison
Keyword(s):  
Low Dose ◽  
Background Radiation ◽  
Threshold Model ◽  
Radiation Risk ◽  
Biomechanical Analysis ◽  
Cellular Damage ◽  
Imaging Method ◽  
X Rays ◽  
Low Dose Radiation ◽  
Dose Radiation

Evidence-based contemporary spinal rehabilitation often requires radiography. Use of radiography (X-rays or computed tomography scans) should not be feared, avoided, or have their exposures lessened to decrease patient dose possibly jeopardizing image quality. This is because all fears of radiation exposures from medical diagnostic imaging are based on complete fabrication of health risks based on an outdated, invalid linear model that has simply been propagated for decades. We present 7 main arguments for continued use of radiography for routine use in spinal rehabilitation: (1) the linear no-threshold model for radiation risk estimates is invalid for low-dose exposures; (2) low-dose radiation enhances health via the body’s adaptive response mechanisms (ie, radiation hormesis); (3) an X-ray with low-dose radiation only induces 1 one-millionth the amount of cellular damage as compared to breathing air for a day; (4) radiography is below inescapable natural annual background radiation levels; (5) radiophobia stems from unwarranted fears and false beliefs; (6) radiography use leads to better patient outcomes; (7) the risk to benefit ratio is always beneficial for routine radiography. Radiography is a safe imaging method for routine use in patient assessment, screening, diagnosis, and biomechanical analysis and for monitoring treatment progress in daily clinical practice.

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