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Calabrese EJ, Selby PB. Muller and mutations: mouse study of George Snell (a postdoc of Muller) fails to confirm Muller's fruit fly findings, and Muller fails to cite Snell's findings. Arch Toxicol 2024; 98:1953-1963. [PMID: 38573337 DOI: 10.1007/s00204-024-03718-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 02/28/2024] [Indexed: 04/05/2024]
Abstract
In 1931, Hermann J. Muller's postdoctoral student, George D. Snell (Nobel Prize recipient--1980) initiated research to replicate with mice Muller's X-ray-induced mutational findings with fruit flies. Snell failed to induce the two types of mutations of interest, based on fly data (sex-linked lethals/recessive visible mutations) even though the study was well designed, used large doses of X-rays, and was published in Genetics. These findings were never cited by Muller, and the Snell paper (Snell, Genetics 20:545-567, 1935) did not cite the 1927 Muller paper (Muller, Science 66:84, 1927). This situation raises questions concerning how Snell wrote the paper (e.g., ignoring the significance of not providing support for Muller's findings in a mammal). The question may be raised whether professional pressures were placed upon Snell to downplay the significance of his findings, which could have negatively impacted the career of Muller and the LNT theory. While Muller would receive worldwide attention, and receive the Nobel Prize in 1946 "for the discovery that mutations can be induced by X-rays," Snell's negative mutation data were almost entirely ignored by his contemporary and subsequent radiation genetics/mutation researchers. This raises questions concerning how the apparent lack of interest in Snell's negative findings helped Muller professionally, including his success in using his fruit fly data to influence hereditary and cancer risk assessment and to obtain the Nobel Prize.
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Affiliation(s)
- Edward J Calabrese
- Toxicology, School of Public Health and Health Sciences, Department of Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA, 01003, USA.
| | - Paul B Selby
- Retired from Oak Ridge National Laboratory at Oak Ridge, TN, 4088 Notting Hill Gate Road, Upper Arlington, OH, 43220, USA
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Calabrese EJ, Selby PB. Muller misled the Pugwash Conference on radiation risks. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2024; 21:136-143. [PMID: 37812193 DOI: 10.1080/15459624.2023.2268664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
The Pugwash Conferences have been a highly visible attempt to create profoundly important discussions on matters related to global safety and security at the highest levels, starting in 1957 at the height of the Cold War. This paper assesses, for the first time, the formal comments offered at this first Pugwash Conference by the Nobel Prize-winning radiation geneticist, Hermann J. Muller, on the effects of ionizing radiation on the human genome. This analysis shows that the presentation by Muller was highly biased and contained scientific errors and misrepresentations of the scientific record that resulted in seriously misleading the attendees. The presentation of Muller at Pugwash served to promote, on a very visible global scale, continued misrepresentations of the state of the science and had a significant impact on policies and practices internationally and both scientific and personal belief systems concerning the effects of low dose radiation on human health. These misrepresentations would come to affect the adoption and use of nuclear technologies and the science of radiological and chemical carcinogen health risk assessment, ultimately having a profound effect on global environmental health.
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Affiliation(s)
- Edward J Calabrese
- Department of Environmental Health Sciences, School of Public Health and Health Sciences, University of Massachusetts Amherst, Amherst, Massachusetts
| | - Paul B Selby
- Oak Ridge National Laboratory, Oak Ridge, Tennessee
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Calabrese EJ, Selby PB. Background radiation and cancer risks: A major intellectual confrontation within the domain of radiation genetics with multiple converging biological disciplines. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2023; 20:621-632. [PMID: 37642576 DOI: 10.1080/15459624.2023.2252032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
This paper assesses the judgments of leading radiation geneticists and cancer risk assessment scientists from the mid-1950s to mid-1970s that background radiation has a significant effect on human genetic disease and cancer incidence. This assumption was adopted by the National Academy of Sciences (NAS) Biological Effects of Atomic Radiation (BEAR) I Genetics Panel for genetic diseases and subsequently applied to cancer risk assessment by other leading individuals/advisory groups (e.g., International Commission on Radiation Protection-ICRP). These recommendations assumed that a sizeable proportion of human mutations originated from background radiation due to cumulative exposure over prolonged reproductive periods and the linear nature of the dose-response. This paper shows that the assumption that background radiation is a significant cause of spontaneous mutation, genetic diseases, and cancer incidence is not supported by experimental and epidemiological findings, and discredits erroneous risk assessments that improperly influenced the recommendations of national and international advisory committees, risk assessment policies, and beliefs worldwide.
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Affiliation(s)
- Edward J Calabrese
- Department of Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA, USA
| | - Paul B Selby
- Retired from Oak Ridge National Laboratory, Oak Ridge, TN, USA
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Selby PB, Calabrese EJ. How self-interest and deception led to the adoption of the linear non-threshold dose response (LNT) model for cancer risk assessment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 898:165402. [PMID: 37454843 DOI: 10.1016/j.scitotenv.2023.165402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 07/06/2023] [Accepted: 07/06/2023] [Indexed: 07/18/2023]
Abstract
This paper clarifies scientific contributions and deceptive/self-serving decisions of William L. Russell and Liane Russell that led to the adoption of the linear non-threshold (LNT) model for cancer risk assessment by the US EPA. By deliberately failing to report an extremely large cluster of mutations in the control group of their first experiment, and thereby greatly suppressing its mutation rate, the Russells incorrectly claimed that the male mouse was 15-fold more susceptible to ionizing-radiation-induced gene mutations as compared with fruit flies. This self-serving error not only propelled their research program into one of great prominence, but it also promoted the LNT-based doubling dose (DD) concept in radiation genetics/cancer risk assessment, by the US National Academy of Sciences (NAS) Biological Effects of Atomic Radiation (BEAR) I Genetics Panel (1956). The DD concept became a central element in their recommendation that regulatory agencies switch from a threshold to an LNT model. This error occurred because of a decision by W. Russell not to report that a large cluster of control group mutations found in an experiment for which preliminary results were reported in 1951. This failure to report that cluster and similar clusters continued throughout the careers of the Russells, resulting in massive overestimation of low dose radiation risks supporting the LNT. The Russell database and the repeated claim that those data show that there is no threshold dose rate for mutation in irradiated mouse stem-cell spermatogonia, have provided mechanistic validation supporting the epidemiological LNT hypothesis for radiation-induced leukemias and cancers. This reanalysis supports the threshold model for both males and females, thereby rebutting epidemiological extrapolations from the NAS and EPA claiming support for the LNT hypothesis for cancer risk assessment. The implications of the Russell errors/deceptions, how/why they occurred, and their impact upon society are enormous and need to be addressed by scientific/regulatory agencies, affecting regulatory and litigation activities.
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Affiliation(s)
- Paul B Selby
- Retired from Oak Ridge National Laboratory at Oak Ridge, TN, Home Address: 4088 Nottinghill Gate Road, Upper Arlington, OH 43220, USA
| | - Edward J Calabrese
- Department of Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA 01003, USA.
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Calabrese EJ, Selby PB. Muller mistakes: The linear no-threshold (LNT) dose response and US EPA's cancer risk assessment policies and practices. Chem Biol Interact 2023; 383:110653. [PMID: 37572872 DOI: 10.1016/j.cbi.2023.110653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 07/28/2023] [Accepted: 08/09/2023] [Indexed: 08/14/2023]
Abstract
This paper identifies the occurrence of six major conceptual scientific errors of Hermann Muller and describes how these errors led to the creation of the linear no-threshold (LNT) dose response historically used worldwide for cancer risk assessments for chemical carcinogens and ionizing radiation. The paper demonstrates the significant role that Muller played in the environmental movement, affecting risk assessment policies and practices that are in force even now a half century following his death. This paper lends support to contemporary research that shows significant limitations of the LNT model for cancer risk assessment.
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Affiliation(s)
- Edward J Calabrese
- School of Public Health and Health Sciences, Amherst, MA, 01003, USA; Department of Environmental Health Sciences, Amherst, MA, 01003, USA; Morrill I, N344, Amherst, MA, 01003, USA; University of Massachusetts, Amherst, MA, 01003, USA.
| | - Paul B Selby
- Retired from Oak Ridge National Laboratory at Oak Ridge, TN, USA.
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Andersson B, Langen B, Liu P, Dávila López M. Development of a machine learning framework for radiation biomarker discovery and absorbed dose prediction. Front Oncol 2023; 13:1156009. [PMID: 37256187 PMCID: PMC10225714 DOI: 10.3389/fonc.2023.1156009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 04/25/2023] [Indexed: 06/01/2023] Open
Abstract
Background Molecular radiation biomarkers are an emerging tool in radiation research with applications for cancer radiotherapy, radiation risk assessment, and even human space travel. However, biomarker screening in genome-wide expression datasets using conventional tools is time-consuming and underlies analyst (human) bias. Machine Learning (ML) methods can improve the sensitivity and specificity of biomarker identification, increase analytical speed, and avoid multicollinearity and human bias. Aim To develop a resource-efficient ML framework for radiation biomarker discovery using gene expression data from irradiated normal tissues. Further, to identify biomarker panels predicting radiation dose with tissue specificity. Methods A strategic search in the Gene Expression Omnibus database identified a transcriptomic dataset (GSE44762) for normal tissues radiation responses (murine kidney cortex and medulla) suited for biomarker discovery using an ML approach. The dataset was pre-processed in R and separated into train and test data subsets. High computational cost of Genetic Algorithm/k-Nearest Neighbor (GA/KNN) mandated optimization and 13 ML models were tested using the caret package in R. Biomarker performance was evaluated and visualized via Principal Component Analysis (PCA) and dose regression. The novelty of ML-identified biomarker panels was evaluated by literature search. Results Caret-based feature selection and ML methods vastly improved processing time over the GA approach. The KNN method yielded overall best performance values on train and test data and was implemented into the framework. The top-ranking genes were Cdkn1a, Gria3, Mdm2 and Plk2 in cortex, and Brf2, Ccng1, Cdkn1a, Ddit4l, and Gria3 in medulla. These candidates successfully categorized dose groups and tissues in PCA. Regression analysis showed that correlation between predicted and true dose was high with R2 of 0.97 and 0.99 for cortex and medulla, respectively. Conclusion The caret framework is a powerful tool for radiation biomarker discovery optimizing performance with resource-efficiency for broad implementation in the field. The KNN-based approach identified Brf2, Ddit4l, and Gria3 mRNA as novel candidates that have been uncharacterized as radiation biomarkers to date. The biomarker panel showed good performance in dose and tissue separation and dose regression. Further training with larger cohorts is warranted to improve accuracy, especially for lower doses.
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Affiliation(s)
- Björn Andersson
- Bioinformatics Core Facility, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Britta Langen
- Department of Radiation Oncology, Division of Molecular Radiation Biology, University of Texas (UT) Southwestern Medical Center, Dallas, TX, United States
| | - Peidi Liu
- Bioinformatics Core Facility, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Marcela Dávila López
- Bioinformatics Core Facility, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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Calabrese EJ, Yazji Shamoun D, Agathokleous E. Dose response and risk assessment: Evolutionary foundations. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 309:119787. [PMID: 35850315 DOI: 10.1016/j.envpol.2022.119787] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 06/08/2022] [Accepted: 07/12/2022] [Indexed: 06/15/2023]
Abstract
The present paper indicates that the origin of the LNT concept for ionizing radiation was based on insufficient understanding of evolution, which precluded the possibility of repair of gene mutation. The denial of such repair processes had important implications, leading to a belief in a linear dose response and thus in Hermann J Muller's proclamation of a Proportionality Rule for ionizing radiation. The paper documents how the lack of repair concept dominated the radiation geneticist community to the 1960s leading to the establishment of the linear no threshold dose response (LNT) model for radiation and chemical reproductive and cancer risk assessment. Research from the late 1950s onward would establish the occurrence, generality, and efficacy of genetic and cellular repair processes. While the assumption of a lack of gene mutation repair was wrong, Muller was correct that dose-response concepts need to be founded on mechanistic understandings of evolution. Such mechanisms require the integration of constitutive and inducible adaptive and repair mechanisms that operate in the low-dose zone. This perspective reflects the comment of Dobzhansky (1973) that "nothing makes sense in biology except in light of evolution." While this is a powerful scientific dictum, it assumes a correct understanding of evolution, something that the origins of the LNT dose response lacked. Such modern mechanistic repair developments reveal that the historical foundations of LNT were flawed from the start. Nonetheless, they have been carried forward to the present time, principally by environmental health regulatory agencies that decoupled risk assessment policy from a sound evolutionary foundation.
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Affiliation(s)
- Edward J Calabrese
- Clinical Assistant Professor, Finance Department, McCombs School of Business, University of Texas at Austin, 2110 Speedway, B6600, Austin, TX, 78712, USA.
| | - Dima Yazji Shamoun
- Clinical Assistant Professor, Finance Department, McCombs School of Business, University of Texas at Austin, 2110 Speedway, B6600, Austin, TX, 78712, USA.
| | - Evgenios Agathokleous
- Professor of Ecology, School of Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing, 210044, China.
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Thresholds for carcinogens. Chem Biol Interact 2021; 341:109464. [PMID: 33823170 DOI: 10.1016/j.cbi.2021.109464] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/28/2021] [Accepted: 03/29/2021] [Indexed: 02/07/2023]
Abstract
Current regulatory cancer risk assessment principles and practices assume a linear dose-response relationship-the linear no-threshold (LNT) model-that theoretically estimates cancer risks occurring following low doses of carcinogens by linearly extrapolating downward from experimentally determined risks at high doses. The two-year rodent bioassays serve as experimental vehicles to determine the high-dose cancer risks in animals and then to predict, by extrapolation, the number of carcinogen-induced tumors (tumor incidence) that will arise during the lifespans of humans who are exposed to environmental carcinogens at doses typically orders of magnitude below those applied in the rodent assays. An integrated toxicological analysis is conducted herein to reconsider an alternative and once-promising approach, tumor latency, for estimating carcinogen-induced cancer risks at low doses. Tumor latency measures time-to-tumor following exposure to a carcinogen, instead of tumor incidence. Evidence for and against the concept of carcinogen-induced tumor latency is presented, discussed, and then examined with respect to its relationship to dose, dose rates, and the dose-related concepts of initiation, tumor promotion, tumor regression, tumor incidence, and hormesis. Considerable experimental evidence indicates: (1) tumor latency (time-to-tumor) is inversely related to the dose of carcinogens and (2) lower doses of carcinogens display quantifiably discrete latency thresholds below which the promotion and, consequently, the progression and growth of tumors are delayed or prevented during a normal lifespan. Besides reconciling well with the concept of tumor promotion, such latency thresholds also reconcile favorably with the existence of thresholds for tumor incidence, the stochastic processes of tumor initiation, and the compensatory repair mechanisms of hormesis. Most importantly, this analysis and the arguments presented herein provide sound theoretical, experimental, and mechanistic rationales for rethinking the foundational premises of low-dose linearity and updating the current practices of cancer risk assessment to include the concept of carcinogen thresholds.
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Calabrese EJ. Ethical failings: The problematic history of cancer risk assessment. ENVIRONMENTAL RESEARCH 2021; 193:110582. [PMID: 33290793 DOI: 10.1016/j.envres.2020.110582] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/01/2020] [Accepted: 12/01/2020] [Indexed: 06/12/2023]
Abstract
This paper demonstrates that unethical conduct by the US National Academy of Sciences (NAS) Biological Effects of Atomic Radiation (BEAR) I Genetics Panel led to their recommendation of the Linear Non-Threshold (LNT) Model for radiation risk assessment and its subsequent adoption by the US and the world community. The analysis, which is based largely on preserved communications of the US NAS Genetics Panel members, reveals that Panel members and their administrative leadership at the NAS displayed an integrated series of unethical actions designed to ensure, (1) the acceptance of the LNT and (2) funding to radiation geneticist panel members and professional colleagues. These findings are significant because major public policies in open democracies, such as cancer risk assessment and other issues impacted by public fears of radiation or chemical exposures, require ethical foundations. Recognition of these ethical failures of the BEAR I Genetics Panel should require a high level administrative, legislative and scientific reassessment of the scientific foundations of cancer risk assessment, with the likely result necessitating revision of current policies and practices. The BEAR I Genetics Panel, 1956 Science journal publication should immediately be retracted because it contains deliberate misrepresentations of the scientific record that were designed to manipulate scientific and public opinion on radiation risk assessment in a dishonest manner.
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Affiliation(s)
- Edward J Calabrese
- Department of Environmental Sciences, University of Massachusetts, Amherst, MA, 01003, USA.
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Calabrese EJ. The Muller-Neel dispute and the fate of cancer risk assessment. ENVIRONMENTAL RESEARCH 2020; 190:109961. [PMID: 32810676 DOI: 10.1016/j.envres.2020.109961] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/14/2020] [Accepted: 07/15/2020] [Indexed: 06/11/2023]
Abstract
The National Academy of Sciences (NAS) Atomic Bomb Casualty Commission (ABCC) human genetic study (i.e., The Neel and Schull, 1956a report) showed an absence of genetic damage in offspring of atomic bomb survivors in support of a threshold model, but was not considered for evaluation by the NAS Biological Effects of Atomic Radiation (BEAR) I Genetics Panel. The study therefore could not impact the Panel's decision to recommend the linear non-threshold (LNT) dose-response model for risk assessment. Summaries and transcripts of the Panel meetings failed to reveal an evaluation of this study, despite its human relevance and ready availability, relying instead on data from Drosophila and mice. This paper explores correspondence among and between BEAR Genetics Panel members, including James Néel, the study director, and other contemporaries to assess why the Panel failed to use these data and how the decision to recommend the LNT model affected future cancer risk assessment policies and practices. This failure of the Genetics Panel was due to: (1) a strongly unified belief in the LNT model among panel members and their refusal to acknowledge that a low dose of radiation could exhibit a threshold, a conclusion that the Néel/Schull atomicbomb study could support, and (2) an excessive degree of self-interest among panel members who experimented with animal models, such as Hermann J. Muller, and feared that human genetic studies would expose the limitations of extrapolating from animal (especially Drosophila) to human responses and would strongly shift research investments/academic grants from animal to human studies. Thus, the failure to consider the Néel/Schull atomic bomb study served both the purposes of preserving the LNT policy goal and ensuring the continued dominance of Muller and his similarly research-oriented colleagues.
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Affiliation(s)
- Edward J Calabrese
- Professor of Toxicology, Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA, 01003, USA.
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Oakley PA, Harrison DE. X-Ray Hesitancy: Patients' Radiophobic Concerns Over Medical X-rays. Dose Response 2020; 18:1559325820959542. [PMID: 32994755 PMCID: PMC7503016 DOI: 10.1177/1559325820959542] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 08/20/2020] [Accepted: 08/25/2020] [Indexed: 12/14/2022] Open
Abstract
All too often the family physician, orthopedic surgeon, dentist or chiropractor is met with radiophobic concerns about X-ray imaging in the clinical setting. These concerns, however, are unwarranted fears based on common but ill-informed and perpetuated ideology versus current understanding of the effects of low-dose radiation exposures. Themes of X-ray hesitancy come in 3 forms: 1. All radiation exposures are harmful (i.e. carcinogenic); 2. Radiation exposures are cumulative; 3. Children are more susceptible to radiation. Herein we address these concerns and find that low-dose radiation activates the body's adaptive responses and leads to reduced cancers. Low-dose radiation is not cumulative as long as enough time (e.g. 24 hrs) passes prior to a repeated exposure, and any damage is repaired, removed, or eliminated. Children have more active immune systems; the literature shows children are no more affected than adults by radiation exposures. Medical X-rays present a small, insignificant addition to background radiation exposure that is not likely to cause harm. Doctors and patients alike should be better informed of the lack of risks from diagnostic radiation and the decision to image should rely on the best evidence, unique needs of the patient, and the expertise of the physician-not radiophobia.
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Calabrese EJ, Agathokleous E. Theodosius Dobzhansky's view on biology and evolution v.2.0: "Nothing in biology makes sense except in light of evolution and evolution's dependence on hormesis-mediated acquired resilience that optimizes biological performance and numerous diverse short and longer term protective strategies". ENVIRONMENTAL RESEARCH 2020; 186:109559. [PMID: 32344211 DOI: 10.1016/j.envres.2020.109559] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 04/15/2020] [Accepted: 04/19/2020] [Indexed: 05/17/2023]
Abstract
The hormetic, biphasic dose response, is highly generalizable, being independent of biological model, level of biological organization, endpoint, inducing agent, and mechanisms. It plays a significant role in mediating both constitutive and adaptable responses in essentially all cells and organisms. The present paper provides both a historical overview of the origin of the hormetic concept in the biological and biomedical sciences, and its potential role in ecology, evolution, and development. These integrative findings provide a broad scientific framework to better understand complex evolutionary-based selection strategies, affecting survival, lifespan, fecundity, learning/memory, tissue repair, reproduction and cooperation, and developmental processes, and offering resilience in the presence of numerous challenges.
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Affiliation(s)
- Edward J Calabrese
- Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA 01003, USA.
| | - Evgenios Agathokleous
- Institute of Ecology, Key Laboratory of Agrometeorology of Jiangsu Province, School of Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing Jiangsu, China.
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Antioxidants versus Food Antioxidant Additives and Food Preservatives. Antioxidants (Basel) 2019; 8:antiox8110542. [PMID: 31717960 PMCID: PMC6912551 DOI: 10.3390/antiox8110542] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 10/30/2019] [Accepted: 11/05/2019] [Indexed: 01/04/2023] Open
Abstract
Natural and processed foods are fragile and can become unpalatable and/or rotten. The processed food industry uses preservatives to enable distribution, even to different continents, and to extend the useful life of their products. Preservatives impede oxidation, a mandatory step in rotting, either by aerobic or anaerobic mechanisms. From a functional point of view, these compounds are antioxidants, and, therefore, a kind of contradiction exists when a preservative is considered “bad” for human health while also thinking that antioxidants provide benefits. The basis of antioxidant action, the doses required for preservation, and the overall antioxidant action are revisited in this work. Finally, the bad and the good of food additives/preservatives are presented, taking into account the main mediator of antioxidant beneficial actions, namely the innate mechanisms of detoxification. Foods that strengthen such innate mechanisms are also presented.
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The Impact of Dose Rate on DNA Double-Strand Break Formation and Repair in Human Lymphocytes Exposed to Fast Neutron Irradiation. Int J Mol Sci 2019; 20:ijms20215350. [PMID: 31661782 PMCID: PMC6862539 DOI: 10.3390/ijms20215350] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 10/16/2019] [Accepted: 10/19/2019] [Indexed: 12/12/2022] Open
Abstract
The lack of information on how biological systems respond to low-dose and low dose-rate exposures makes it difficult to accurately assess the carcinogenic risks. This is of critical importance to space radiation, which remains a serious concern for long-term manned space exploration. In this study, the γ-H2AX foci assay was used to follow DNA double-strand break (DSB) induction and repair following exposure to neutron irradiation, which is produced as secondary radiation in the space environment. Human lymphocytes were exposed to high dose-rate (HDR: 0.400 Gy/min) and low dose-rate (LDR: 0.015 Gy/min) p(66)/Be(40) neutrons. DNA DSB induction was investigated 30 min post exposure to neutron doses ranging from 0.125 to 2 Gy. Repair kinetics was studied at different time points after a 1 Gy neutron dose. Our results indicated that γ-H2AX foci formation was 40% higher at HDR exposure compared to LDR exposure. The maximum γ-H2AX foci levels decreased gradually to 1.65 ± 0.64 foci/cell (LDR) and 1.29 ± 0.45 (HDR) at 24 h postirradiation, remaining significantly higher than background levels. This illustrates a significant effect of dose rate on neutron-induced DNA damage. While no significant difference was observed in residual DNA damage after 24 h, the DSB repair half-life of LDR exposure was slower than that of HDR exposure. The results give a first indication that the dose rate should be taken into account for cancer risk estimations related to neutrons.
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Hormetic and Mitochondria-Related Mechanisms of Antioxidant Action of Phytochemicals. Antioxidants (Basel) 2019; 8:antiox8090373. [PMID: 31487950 PMCID: PMC6769633 DOI: 10.3390/antiox8090373] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 08/11/2019] [Accepted: 08/28/2019] [Indexed: 12/12/2022] Open
Abstract
Antioxidant action to afford a health benefit or increased well-being may not be directly exerted by quick reduction-oxidation (REDOX) reactions between the antioxidant and the pro-oxidant molecules in a living being. Furthermore, not all flavonoids or polyphenols derived from plants are beneficial. This paper aims at discussing the variety of mechanisms underlying the so-called "antioxidant" action. Apart from antioxidant direct mechanisms, indirect ones consisting of fueling and boosting innate detox routes should be considered. One of them, hormesis, involves upregulating enzymes that are needed in innate detox pathways and/or regulating the transcription of the so-called vitagenes. Moreover, there is evidence that some plant-derived compounds may have a direct role in events taking place in mitochondria, which is an organelle prone to oxidative stress if electron transport is faulty. Insights into the potential of molecules able to enter into the electron transport chain would require the determination of their reduction potential. Additionally, it is advisable to know both the oxidized and the reduced structures for each antioxidant candidate. These mechanisms and their related technical developments should help nutraceutical industry to select candidates that are efficacious in physiological conditions to prevent diseases or increase human health.
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Abstract
When people discuss the risks associated with low doses of ionizing radiation, central to the discussion is the definition of a low dose and the nature of harm. Standard answers such as "doses below 0.1 Gy are low" or "cancer is the most sensitive measure of harm" obscure the complexity within these seemingly simple questions. This paper will discuss some of the complex issues involved in determining risks to human and nonhuman species from low-dose exposures. Central to this discussion will be the role of communicable responses to all stressors (often referred to as bystander responses), which include recently discovered epigenetic and nontargeted mechanisms. There is a growing consensus that low-dose exposure to radiation is but one of many stressors to impact populations. Many of these stressors trigger responses that are generic and not unique to radiation. The lack of a unique radiation signature makes absolute definition of radiation risk difficult. This paper examines a possible new way of defining low dose based on the systemic response to the radiation. Many factors will influence this systemic response and, because it is inherently variable, it is difficult to predict and so makes low-dose responses very uncertain. Rather than seeking to reduce uncertainty, it might be valuable to accept the variability in outcomes, which arise from the complexity and multifactorial nature of responses to stressors.
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Affiliation(s)
| | - Andrej Rusin
- Department of Biology, McMaster University, Hamilton, Canada
| | - Colin Seymour
- Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Canada
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Agathokleous E, Araminiene V, Belz RG, Calatayud V, De Marco A, Domingos M, Feng Z, Hoshika Y, Kitao M, Koike T, Paoletti E, Saitanis CJ, Sicard P, Calabrese EJ. A quantitative assessment of hormetic responses of plants to ozone. ENVIRONMENTAL RESEARCH 2019; 176:108527. [PMID: 31203049 DOI: 10.1016/j.envres.2019.108527] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/18/2019] [Accepted: 06/06/2019] [Indexed: 06/09/2023]
Abstract
Evaluations of ozone effects on vegetation across the globe over the last seven decades have mostly incorporated exposure levels that were multi-fold the preindustrial concentrations. As such, global risk assessments and derivation of critical levels for protecting plants and food supplies were based on extrapolation from high to low exposure levels. These were developed in an era when it was thought that stress biology is framed around a linear dose-response. However, it has recently emerged that stress biology commonly displays non-linear, hormetic processes. The current biological understanding highlights that the strategy of extrapolating from high to low exposure levels may lead to biased estimates. Here, we analyzed a diverse sample of published empirical data of approximately 500 stimulatory, hormetic-like dose-responses induced by ozone in plants. The median value of the maximum stimulatory responses induced by elevated ozone was 124%, and commonly <150%, of the background response (control), independently of species and response variable. The maximum stimulatory response to ozone was similar among types of response variables and major plant species. It was also similar among clades, between herbaceous and woody plants, between deciduous and evergreen trees, and between annual and perennial herbaceous plants. There were modest differences in the stimulatory response between genera and between families which may reflect different experimental designs and conditions among studies. The responses varied significantly upon type of exposure system, with open-top chambers (OTCs) underestimating the maximum stimulatory response compared to free-air ozone-concentration enrichment (FACE) systems. These findings suggest that plants show a generalized hormetic stimulation by ozone which is constrained within certain limits of biological plasticity, being highly generalizable, evolutionarily based, and maintained over ecological scales. They further highlight that non-linear responses should be taken into account when assessing the ozone effects on plants.
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Affiliation(s)
- Evgenios Agathokleous
- Institute of Ecology, Key Laboratory of Agrometeorology of Jiangsu Province, School of Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing, 210044, China.
| | - Valda Araminiene
- Lithuanian Research Centre for Agriculture and Forestry, Institute of Forestry, Girionys, Lithuania
| | - Regina G Belz
- University of Hohenheim, Agroecology Unit, Hans-Ruthenberg Institute, 70593, Stuttgart, Germany
| | - Vicent Calatayud
- Fundación CEAM, Charles R. Darwin 14, Parque Tecnológico, 46980, Paterna, Spain
| | - Alessandra De Marco
- Italian National Agency for New Technologies, Energy and the Environment (ENEA), C.R. Casaccia, SSPT-PVS, Via Anguillarese 301, S. Maria di Galeria, Rome, 00123, Italy
| | - Marisa Domingos
- Instituto de Botânica, Núcleo de Pesquisa em Ecologia, PO Box 68041, 04045-972, SP, Brazil
| | - ZhaoZhong Feng
- Institute of Ecology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing, 210044, China
| | - Yasutomo Hoshika
- National Council of Research, Via Madonna del Piano 10, Sesto Fiorentino, Florence, 50019, Italy
| | - Mitsutoshi Kitao
- Hokkaido Research Center, Forestry and Forest Products Research Institute (FFPRI), Forest Research and Management Organization, 7 Hitsujigaoka, Sapporo, Hokkaido, 062-8516, Japan
| | - Takayoshi Koike
- Research Faculty of Agriculture, Hokkaido University, Kita 9 Nishi 9, Sapporo, Hokkaido, 060-8589, Japan
| | - Elena Paoletti
- National Council of Research, Via Madonna del Piano 10, Sesto Fiorentino, Florence, 50019, Italy
| | - Costas J Saitanis
- Lab of Ecology and Environmental Science, Agricultural University of Athens, Iera Odos 75, Athens, 11855, Greece
| | - Pierre Sicard
- ARGANS, 260 route du Pin Montard, 06410, Biot, France
| | - Edward J Calabrese
- Department of Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA, 01003, USA
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18
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Calabrese EJ. EPA adopts LNT: New historical perspectives. Chem Biol Interact 2019; 308:110-112. [DOI: 10.1016/j.cbi.2019.05.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 05/13/2019] [Accepted: 05/15/2019] [Indexed: 11/16/2022]
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19
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Giuffrida D. Individual radiation protection: idea and research needs. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2019; 39:641-646. [PMID: 30794994 DOI: 10.1088/1361-6498/ab0979] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
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20
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Ulyanenko S, Pustovalova M, Koryakin S, Beketov E, Lychagin A, Ulyanenko L, Kaprin A, Grekhova A, M Ozerova A, V Ozerov I, Vorobyeva N, Shegay P, Ivanov S, Leonov S, Klokov D, Osipov AN. Formation of γH2AX and pATM Foci in Human Mesenchymal Stem Cells Exposed to Low Dose-Rate Gamma-Radiation. Int J Mol Sci 2019; 20:E2645. [PMID: 31146367 PMCID: PMC6600277 DOI: 10.3390/ijms20112645] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/21/2019] [Accepted: 05/23/2019] [Indexed: 12/12/2022] Open
Abstract
DNA double-strand breaks (DSB) are among the most harmful DNA lesions induced by ionizing radiation (IR). Although the induction and repair of radiation-induced DSB is well studied for acute irradiation, responses to DSB produced by chronic IR exposures are poorly understood, especially in human stem cells. The aim of this study was to examine the formation of DSB markers (γH2AX and phosphorylated kinase ATM, pATM, foci) in human mesenchymal stem cells (MSCs) exposed to chronic gamma-radiation (0.1 mGy/min) in comparison with acute irradiation (30 mGy/min) at cumulative doses of 30, 100, 160, 240 and 300 mGy. A linear dose-dependent increase in the number of both γH2AX and pATM foci, as well as co-localized γH2AX/pATM foci ("true" DSB), were observed after an acute radiation exposure. In contrast, the response of MSCs to a chronic low dose-rate IR exposure deviated from linearity towards a threshold model, for γH2AX, pATM foci and γH2AX/pATM foci, with an indication of a "plateau". The state of equilibrium between newly formed DSB at a low rate during the protracted exposure time and the elimination of a fraction of DSB is proposed as a mechanistic explanation of the non-linear DSB responses following a low dose-rate irradiation. This notion is supported by the observation of the elimination of a substantial fraction of DSB 6 h after the cessation of the exposures. Our results demonstrate non-linear dose responses for γH2AX and pATM foci in human MSCs exposed to low dose-rate IR and showed the existence of a threshold, which may have implications for radiation protection in humans.
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Affiliation(s)
- Stepan Ulyanenko
- A. Tsyb Medical Radiological Research Centre-Branch of the National Medical Research Radiological Centre of the Ministry of Health of the Russian Federation, Koroleva 4, Obninsk 249030, Russia.
| | - Margarita Pustovalova
- State Research Center-Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency, Moscow 123098, Russia.
- Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow 119991, Russia.
- Moscow Institute of Physics and Technology, Dolgoprudny 141700, Russia.
| | - Sergey Koryakin
- A. Tsyb Medical Radiological Research Centre-Branch of the National Medical Research Radiological Centre of the Ministry of Health of the Russian Federation, Koroleva 4, Obninsk 249030, Russia.
| | - Evgenii Beketov
- A. Tsyb Medical Radiological Research Centre-Branch of the National Medical Research Radiological Centre of the Ministry of Health of the Russian Federation, Koroleva 4, Obninsk 249030, Russia.
| | - Anatolii Lychagin
- A. Tsyb Medical Radiological Research Centre-Branch of the National Medical Research Radiological Centre of the Ministry of Health of the Russian Federation, Koroleva 4, Obninsk 249030, Russia.
| | - Liliya Ulyanenko
- A. Tsyb Medical Radiological Research Centre-Branch of the National Medical Research Radiological Centre of the Ministry of Health of the Russian Federation, Koroleva 4, Obninsk 249030, Russia.
| | - Andrey Kaprin
- National Medical Research Radiological Centre of the Ministry of Health of the Russian Federation, Moscow 125284, Russia.
| | - Anna Grekhova
- State Research Center-Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency, Moscow 123098, Russia.
- Emanuel Institute for Biochemical Physics, Russian Academy of Sciences, Moscow 119991, Russia.
| | - Alexandra M Ozerova
- Faculty of Biology, Lomonosov Moscow State University, GSP-1, Leninskie Gory, Moscow 119991, Russia.
| | - Ivan V Ozerov
- State Research Center-Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency, Moscow 123098, Russia.
| | - Natalia Vorobyeva
- State Research Center-Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency, Moscow 123098, Russia.
- Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow 119991, Russia.
| | - Peter Shegay
- Center for Innovative Radiological and Regenerative Technologies of the Ministry of Health of the Russian Federation, Koroleva 4, Obninsk 249030, Russia.
| | - Sergey Ivanov
- A. Tsyb Medical Radiological Research Centre-Branch of the National Medical Research Radiological Centre of the Ministry of Health of the Russian Federation, Koroleva 4, Obninsk 249030, Russia.
| | - Sergey Leonov
- Moscow Institute of Physics and Technology, Dolgoprudny 141700, Russia.
- Institute of Cell Biophysics, Russian Academy of Sciences, Institutskaya St., 3, Pushchino 142290, Russia.
| | - Dmitry Klokov
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
| | - Andreyan N Osipov
- State Research Center-Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency, Moscow 123098, Russia.
- Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow 119991, Russia.
- Moscow Institute of Physics and Technology, Dolgoprudny 141700, Russia.
- Center for Innovative Radiological and Regenerative Technologies of the Ministry of Health of the Russian Federation, Koroleva 4, Obninsk 249030, Russia.
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21
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Agathokleous E, Anav A, Araminiene V, De Marco A, Domingos M, Kitao M, Koike T, Manning WJ, Paoletti E, Saitanis CJ, Sicard P, Vitale M, Wang W, Calabrese EJ. Commentary: EPA's proposed expansion of dose-response analysis is a positive step towards improving its ecological risk assessment. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 246:566-570. [PMID: 30594897 DOI: 10.1016/j.envpol.2018.12.046] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 12/11/2018] [Accepted: 12/15/2018] [Indexed: 05/17/2023]
Abstract
The United States Environmental Protection Agency (US EPA) has recently proposed changes to strengthen the transparency of its pivotal regulatory science policy and procedures. In this context, the US EPA aims to enhance the transparency of dose-response data and models, proposing to consider for the first time non-linear biphasic dose-response models. While the proposed changes have the potential to lead to markedly improved ecological risk assessment compared to past and current approaches, we believe there remain open issues for improving the quality of ecological risk assessment, such as the consideration of adaptive, dynamic and interactive effects. Improved risk assessment including adaptive and dynamic non-linear models (beyond classic threshold models) can enhance the quality of regulatory decisions and the protection of ecological health. We suggest that other countries consider adopting a similar scientific-regulatory posture with respect to dose-response modeling via the inclusion of non-linear biphasic models, that incorporate the dynamic potential of biological systems to adapt (i.e., enhancing positive biological endpoints) or maladapt to low levels of stressor agents.
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Affiliation(s)
- Evgenios Agathokleous
- Hokkaido Research Center, Forestry and Forest Products Research Institute (FFPRI), Forest Research and Management Organization, 7 Hitsujigaoka, Sapporo, Hokkaido, 062-8516, Japan; Research Faculty of Agriculture, Hokkaido University, Kita 9 Nishi 9, Sapporo, Hokkaido, 060-8589, Japan.
| | - Alessandro Anav
- National Council of Research, Via Madonna del Piano 10, Sesto Fiorentino, Florence, 50019, Italy
| | - Valda Araminiene
- Institute of Forestry, Lithuanian Research Centre for Agriculture and Forestry, Girionys, 53101, Kaunas district, Lithuania
| | - Alessandra De Marco
- Italian National Agency for New Technologies, Energy and the Environment (ENEA), C.R. Casaccia, S. Maria di Galeria, Rome, 00123, Italy
| | - Marisa Domingos
- Instituto de Botânica, Núcleo de Pesquisa em Ecologia, PO Box 68041, 04045-972, SP, Brazil
| | - Mitsutoshi Kitao
- Hokkaido Research Center, Forestry and Forest Products Research Institute (FFPRI), Forest Research and Management Organization, 7 Hitsujigaoka, Sapporo, Hokkaido, 062-8516, Japan
| | - Takayoshi Koike
- Research Faculty of Agriculture, Hokkaido University, Kita 9 Nishi 9, Sapporo, Hokkaido, 060-8589, Japan
| | - William J Manning
- Department of Plant, Soil and Insect Sciences, University of Massachusetts, Amherst, MA, USA
| | - Elena Paoletti
- National Council of Research, Via Madonna del Piano 10, Sesto Fiorentino, Florence, 50019, Italy
| | - Costas J Saitanis
- Lab of Ecology and Environmental Science, Agricultural University of Athens, Iera Odos 75, Athens, 11855, Greece
| | - Pierre Sicard
- ARGANS, 260 route du Pin Montard, Sophia Antipolis cedex, 06904, France
| | - Marcello Vitale
- Department of Environmental Biology, Sapienza University of Rome, Piazzale Aldo Moro 5, Rome, 00185, Italy
| | - Wenjie Wang
- Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China; Northeast Forestry University, Harbin, 150040, China
| | - Edward J Calabrese
- Department of Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA, 01003, USA
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Franco R, Navarro G, Martínez-Pinilla E. Antioxidant Defense Mechanisms in Erythrocytes and in the Central Nervous System. Antioxidants (Basel) 2019; 8:antiox8020046. [PMID: 30781629 PMCID: PMC6406447 DOI: 10.3390/antiox8020046] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 02/09/2019] [Accepted: 02/13/2019] [Indexed: 12/16/2022] Open
Abstract
Differential antioxidant action is found upon comparison of organ/tissue systems in the human body. In erythrocytes (red blood cells), which transport oxygen and carbon dioxide through the circulatory system, the most important issue is to keep hemoglobin in a functional state that requires maintaining the haem group in ferrous (Fe2+) state. Conversion of oxidized Fe3+ back into Fe2+ in hemoglobin needs a special mechanism involving a tripeptide glutathione, glucose-6-phosphate dehydrogenase, and glucose and NADPH as suppliers of reducing power. Fava beans are probably a good resource to make the detox innate system more robust as the pro-oxidant molecules in this food likely induce the upregulation of members of such mechanisms. The central nervous system consumes more oxygen than the majority of human tissues, i.e., 20% of the body's total oxygen consumption and, therefore, it is exposed to a high level of oxidative stress. This fact, together with the progressive age-related decline in the efficiency of the antioxidant defense system, leads to neuronal death and disease. The innate mechanism operating in the central nervous system is not well known and seems different to that of the erythrocytes. The strategies of antioxidant intervention in brain will be reviewed here.
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Affiliation(s)
- Rafael Franco
- Molecular Neurobiology Laboratory, Department of Biochemistry and Molecular Biomedicine, Biology School, University of Barcelona, Barcelona 08028, Spain.
- Centro de Investigación en Red, Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid 28031, Spain.
| | - Gemma Navarro
- Centro de Investigación en Red, Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid 28031, Spain.
- Department of Biochemistry and Physiology, Pharmacy and Food Science School, University of Barcelona, Barcelona 08028, Spain.
| | - Eva Martínez-Pinilla
- Departamento de Morfología y Biología Celular, Facultad de Medicina, Universidad de Oviedo, Asturias 33006, Spain.
- Instituto de Neurociencias del Principado de Asturias (INEUROPA), Asturias 33006, Spain.
- Instituto de Salud del Principado de Asturias (ISPA), Asturias 33006, Spain.
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Calabrese EJ. The linear No-Threshold (LNT) dose response model: A comprehensive assessment of its historical and scientific foundations. Chem Biol Interact 2019; 301:6-25. [PMID: 30763547 DOI: 10.1016/j.cbi.2018.11.020] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 11/26/2018] [Indexed: 11/24/2022]
Abstract
The linear no-threshold (LNT) single-hit (SH) dose response model for cancer risk assessment is comprehensively assessed with respect to its historical foundations. This paper also examines how mistakes, ideological biases, and scientific misconduct by key scientists affected the acceptance, validity, and applications of the LNT model for cancer risk assessment. In addition, the analysis demonstrates that the LNT single-hit model was inappropriately adopted for governmental risk assessment, regulatory policy, practices, and for risk communication.
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Affiliation(s)
- Edward J Calabrese
- Department of Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA, 01003, USA.
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24
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Calabrese EJ, Giordano JJ, Kozumbo WJ, Leak RK, Bhatia TN. Hormesis mediates dose-sensitive shifts in macrophage activation patterns. Pharmacol Res 2018; 137:236-249. [DOI: 10.1016/j.phrs.2018.10.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 10/09/2018] [Accepted: 10/09/2018] [Indexed: 02/07/2023]
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25
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Ulsh BA. A critical evaluation of the NCRP COMMENTARY 27 endorsement of the linear no-threshold model of radiation effects. ENVIRONMENTAL RESEARCH 2018; 167:472-487. [PMID: 30138826 DOI: 10.1016/j.envres.2018.08.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 07/31/2018] [Accepted: 08/03/2018] [Indexed: 06/08/2023]
Abstract
Regulatory policy to protect the public and the environment from radiation is universally based on the linear, no-threshold model (LNT) of radiation effects. This model has been controversial since its inception over nine decades ago, and remains so to this day, but it has proved remarkably resistant to challenge from the scientific community. The LNT model has been repeatedly endorsed by expert advisory bodies, and regulatory agencies in turn adopt policies that reflect this advice. Unfortunately, these endorsements rest on a foundation of institutional inertia and numerous logical fallacies. These include most significantly setting the LNT as the null hypothesis, and shifting the burden of proof onto LNT skeptics. Other examples include arbitrary exclusion of alternative hypotheses, ignoring criticisms of the LNT, cherry-picking evidence, and making policy judgements without foundation. This paper presents an evaluation of the National Council on Radiation Protection and Measurements' (NCRP) Commentary 27, which concluded that recent epidemiological studies are compatible with the continued use of the LNT model for radiation protection. While this report will likely provide political cover for regulators' continued reliance on the LNT, it is a missed opportunity to advance the scientific discussion of the effects of low dose, low dose-rate radiation exposure. Due to its Congressionally chartered mission, no organization is better positioned than the NCRP to move this debate forward, and recommendations for doing so in future reviews are provided.
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Affiliation(s)
- Brant A Ulsh
- M. H. Chew & Associates, 7633 Southfront Rd, Ste. 170, Livermore, CA 94551-8211, United States.
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26
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Calabrese EJ. Muller's nobel prize research and peer review. Philos Ethics Humanit Med 2018; 13:15. [PMID: 30336788 PMCID: PMC6194698 DOI: 10.1186/s13010-018-0066-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 09/18/2018] [Indexed: 06/08/2023] Open
Abstract
BACKGROUND This paper assesses possible reasons why Hermann J. Muller avoided peer-review of data that became the basis of his Nobel Prize award for producing gene mutations in male Drosophila by X-rays. METHODS Extensive correspondence between Muller and close associates and other materials were obtained from preserved papers to compliment extensive publications by and about Muller in the open literature. These were evaluated for potential historical insights that clarify why he avoided peer-review of his Nobel Prize findings. RESULTS This paper clarifies the basis of Muller's (Muller HJ, Sci 66 84-87, 1927c) belief that he produced X-ray induced "gene" mutations in Drosophila. It then shows his belief was contemporaneously challenged by his longtime friend/confidant and Drosophila geneticist, Edgar Altenburg. Altenburg insisted that Muller may have simply poked large holes in chromosomes with massive doses of X-rays, and needed to provide proof of gene "point" mutations. Given the daunting and uncertain task to experimentally address this criticism, especially within the context of trying to become first to produce gene mutations, it is proposed that Muller purposely avoided peer-review while rushing to publish his paper in Science to claim discovery primacy without showing any data. The present paper also explores ethical issues surrounding these actions, including those of the editor of Science, James McKeen Catell and Altenburg, and their subsequent impact on the scientific and regulatory communities. CONCLUSION This historical analysis suggests that Muller deliberately avoided peer-review on his most significant findings because he was extremely troubled by the insightful and serious criticism of Altenburg, which suggested he had not produced gene mutations as he claimed. Nonetheless, Muller manipulated this situation (i.e., publishing a discussion within Science with no data, publishing a poorly written non-peer reviewed conference proceedings with no methods and materials, and no references) due to both the widespread euphoria over his claim of gene mutation and confidence that Altenburg would not publically challenge him. This situation permitted Muller to achieve his goal to be the first to produce gene mutations while buying him time to later try to experimentally address Altenburg's criticisms, and a possible way to avoid discovery of his questionable actions.
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Affiliation(s)
- Edward J Calabrese
- Department of Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA, 01003, USA.
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27
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Costantini D, Borremans B. The linear no-threshold model is less realistic than threshold or hormesis-based models: An evolutionary perspective. Chem Biol Interact 2018; 301:26-33. [PMID: 30342016 DOI: 10.1016/j.cbi.2018.10.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 10/12/2018] [Accepted: 10/16/2018] [Indexed: 12/30/2022]
Abstract
The linear no-threshold (LNT) risk model is the current human health risk assessment paradigm. This model states that adverse stochastic biological responses to high levels of a stressor can be used to estimate the response to low or moderate levels of that stressor. In recent years the validity of the LNT risk model has increasingly been questioned because of the recurring observation that an organism's response to high stressor doses differs from that to low doses. This raises important questions about the biological and evolutionary validity of the LNT model. In this review we reiterate that the LNT model as applied to stochastic biological effects of low and moderate stressor levels has less biological validity than threshold or, particularly, hormetic models. In so doing, we rely heavily on literature from disciplines like ecophysiology or evolutionary ecology showing how exposure to moderate amounts of stress can have severe impacts on phenotype and organism reproductive fitness. We present a mathematical model that illustrates and explores the hypothetical conditions that make a particular kind of hormesis (conditioning hormesis) ecologically and evolutionarily plausible.
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Affiliation(s)
- David Costantini
- UMR 7221 CNRS/MNHN, Muséum National d'Histoire Naturelle, Sorbonne Universités, 7 rue Cuvier, 75005, Paris, France; Behavioural Ecology & Ecophysiology Group, Department of Biology, University of Antwerp, Universiteitsplein 1, 2610, Wilrijk, Belgium.
| | - Benny Borremans
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, 610 Charles E. Young Dr. South, Los Angeles, 90095, United States; Evolutionary Ecology Group, Department of Biology, University of Antwerp, Universiteitsplein 1, 2610, Wilrijk, Belgium; Interuniversity Institute for Biostatistics and Statistical Bioinformatics (I-BIOSTAT), Hasselt University, Agoralaan gebouw D, 3590, Diepenbeek, Belgium
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28
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Calabrese EJ. From Muller to mechanism: How LNT became the default model for cancer risk assessment. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 241:289-302. [PMID: 29843011 DOI: 10.1016/j.envpol.2018.05.051] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 05/15/2018] [Accepted: 05/16/2018] [Indexed: 06/08/2023]
Abstract
This paper summarizes the historical and scientific foundations of the Linear No-Threshold (LNT) cancer risk assessment model. The story of cancer risk assessment is an extraordinary one as it was based on an initial incorrect gene mutation interpretation of Muller, the application of this incorrect assumption in the derivation of the LNT single-hit model, and a series of actions by leading radiation geneticists during the 1946-1956 period, including a National Academy of Sciences (NAS) Biological Effects of Atomic Radiation (BEAR) I Genetics Panel (Anonymous, 1956), to sustain the LNT belief via a series of deliberate obfuscations, deceptions and misrepresentations that provided the basis of modern cancer risk assessment policy and practices. The reaffirming of the LNT model by a subsequent and highly influential NAS Biological Effects of Ionizing Radiation (BEIR) I Committee (NAS/NRC, 1972) using mouse data has now been found to be inappropriate based on the discovery of a significant documented error in the historical control group that led to incorrect estimations of risk in the low dose zone. Correction of this error by the original scientists and the application of the adjusted/corrected data back to the BEIR I (NAS/NRC, 1972) report indicates that the data would have supported a threshold rather than the LNT model. Thus, cancer risk assessment has a poorly appreciated, complex and seriously flawed history that has undermined policies and practices of regulatory agencies in the U.S. and worldwide to the present time.
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Affiliation(s)
- Edward J Calabrese
- Department of Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA, 01003, USA.
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Hormesis: Path and Progression to Significance. Int J Mol Sci 2018; 19:ijms19102871. [PMID: 30248927 PMCID: PMC6213774 DOI: 10.3390/ijms19102871] [Citation(s) in RCA: 128] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 09/06/2018] [Accepted: 09/17/2018] [Indexed: 12/20/2022] Open
Abstract
This paper tells the story of how hormesis became recognized as a fundamental concept in biology, affecting toxicology, microbiology, medicine, public health, agriculture, and all areas related to enhancing biological performance. This paper assesses how hormesis enhances resilience to normal aging and protects against a broad spectrum of neurodegenerative, cardiovascular, and other diseases, as well as trauma and other threats to health and well-being. This paper also explains the application of hormesis to several neurodegenerative diseases such as Parkinson’s and Huntington’s disease, macrophage polarization and its systematic adaptive protections, and the role of hormesis in enhancing stem cell functioning and medical applications.
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Agathokleous E, Kitao M, Calabrese EJ. Emission of volatile organic compounds from plants shows a biphasic pattern within an hormetic context. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 239:318-321. [PMID: 29665552 DOI: 10.1016/j.envpol.2018.04.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 04/04/2018] [Accepted: 04/06/2018] [Indexed: 05/03/2023]
Abstract
Biogenic volatile organic compounds (BVOCs) are released to the atmosphere from vegetation. BVOCs aid in maintaining ecosystem sustainability via a series of functions, however, VOCs can alter tropospheric photochemistry and negatively affect biological organisms at high concentrations. Due to their critical role in ecosystem and environmental sustainability, BVOCs receive particular attention by global change biologists. To understand how plant VOC emissions affect stress responses within a dose-response context, dose responses should be evaluated. This commentary collectively documents hormetic-like responses of plant-emitted VOCs to external stimuli. Hormesis is a generalizable biphasic dose response phenomenon where the response to low doses acts in an opposite way at high doses. These collective findings suggest that ecological implications of low-level stress that may alter BVOC emissions should be considered in future studies. This commentary promotes new insights into the interface between biological systems and environmental change that influence several parts of the globe, and provide a base for advancing hazard assessment testing strategies and protocols to provide decision makers with adequate data for generating environmental standards.
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Affiliation(s)
- Evgenios Agathokleous
- Hokkaido Research Center, Forestry and Forest Products Research Institute (FFPRI), Forest Research and Management Organization, 7 Hitsujigaoka, Sapporo, Hokkaido, 062-8516, Japan; Research Faculty of Agriculture, Hokkaido University, Kita 9 Nishi 9, Sapporo, Hokkaido, 060-8589, Japan.
| | - Mitsutoshi Kitao
- Hokkaido Research Center, Forestry and Forest Products Research Institute (FFPRI), Forest Research and Management Organization, 7 Hitsujigaoka, Sapporo, Hokkaido, 062-8516, Japan.
| | - Edward J Calabrese
- Department of Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA 01003, USA.
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Agathokleous E, Kitao M, Calabrese EJ. Environmental hormesis and its fundamental biological basis: Rewriting the history of toxicology. ENVIRONMENTAL RESEARCH 2018; 165:274-278. [PMID: 29734028 DOI: 10.1016/j.envres.2018.04.034] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 03/29/2018] [Accepted: 04/30/2018] [Indexed: 05/09/2023]
Abstract
It has long been debated whether a little stress may be "good" for you. Extensive evidence has now sufficiently accumulated demonstrating that low doses of a vast range of chemical and physical agents induce protective/beneficial effects while the opposite occurs at higher doses, a phenomenon known as hormesis. Low doses of environmental agents have recently induced autophagy, a critical adaptive response that protects essentially all cell types, as well as being transgenerational via epigenetic mechanisms. These collective findings highlight a generalized and substantial ongoing dose-response transformation with significant implications for disease biology and clinical applications, challenging the history and practice of toxicology and pharmacology along with an appeal to stake holders to reexamine the process of risk assessment, with the goal of optimizing public health rather than simply avoiding harm.
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Affiliation(s)
- Evgenios Agathokleous
- Hokkaido Research Center, Forestry and Forest Products Research Institute (FFPRI), Forest Research and Management Organization, 7 Hitsujigaoka, Sapporo, Hokkaido 062-8516, Japan; Research Faculty of Agriculture, Hokkaido University, Kita 9 Nishi 9, Sapporo, Hokkaido 060-8589, Japan.
| | - Mitsutoshi Kitao
- Hokkaido Research Center, Forestry and Forest Products Research Institute (FFPRI), Forest Research and Management Organization, 7 Hitsujigaoka, Sapporo, Hokkaido 062-8516, Japan.
| | - Edward J Calabrese
- Department of Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA 01003, USA.
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Cardarelli JJ, Ulsh BA. It Is Time to Move Beyond the Linear No-Threshold Theory for Low-Dose Radiation Protection. Dose Response 2018; 16:1559325818779651. [PMID: 30013457 PMCID: PMC6043938 DOI: 10.1177/1559325818779651] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 04/18/2018] [Accepted: 05/01/2018] [Indexed: 02/03/2023] Open
Abstract
The US Environmental Protection Agency (USEPA) is the primary federal agency responsible for promulgating regulations and policies to protect people and the environment from ionizing radiation. Currently, the USEPA uses the linear no-threshold (LNT) model to estimate cancer risks and determine cleanup levels in radiologically contaminated environments. The LNT model implies that there is no safe dose of ionizing radiation; however, adverse effects from low dose, low-dose rate (LDDR) exposures are not detectable. This article (1) provides the scientific basis for discontinuing use of the LNT model in LDDR radiation environments, (2) shows that there is no scientific consensus for using the LNT model, (3) identifies USEPA reliance on outdated scientific information, and (4) identifies regulatory reliance on incomplete evaluations of recent data contradicting the LNT. It is the time to reconsider the use of the LNT model in LDDR radiation environments. Incorporating the latest science into the regulatory process for risk assessment will (1) ensure science remains the foundation for decision making, (2) reduce unnecessary burdens of costly cleanups, (3) educate the public on the real effects of LDDR radiation exposures, and (4) harmonize government policies with the rest of the radiation scientific community.
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Vaiserman A, Koliada A, Zabuga O, Socol Y. Health Impacts of Low-Dose Ionizing Radiation: Current Scientific Debates and Regulatory Issues. Dose Response 2018; 16:1559325818796331. [PMID: 30263019 PMCID: PMC6149023 DOI: 10.1177/1559325818796331] [Citation(s) in RCA: 109] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 07/30/2018] [Accepted: 07/31/2018] [Indexed: 12/31/2022] Open
Abstract
Health impacts of low-dose ionizing radiation are significant in important fields such as X-ray imaging, radiation therapy, nuclear power, and others. However, all existing and potential applications are currently challenged by public concerns and regulatory restrictions. We aimed to assess the validity of the linear no-threshold (LNT) model of radiation damage, which is the basis of current regulation, and to assess the justification for this regulation. We have conducted an extensive search in PubMed. Special attention has been given to papers cited in comprehensive reviews of the United States (2006) and French (2005) Academies of Sciences and in the United Nations Scientific Committee on Atomic Radiation 2016 report. Epidemiological data provide essentially no evidence for detrimental health effects below 100 mSv, and several studies suggest beneficial (hormetic) effects. Equally significant, many studies with in vitro and in animal models demonstrate that several mechanisms initiated by low-dose radiation have beneficial effects. Overall, although probably not yet proven to be untrue, LNT has certainly not been proven to be true. At this point, taking into account the high price tag (in both economic and human terms) borne by the LNT-inspired regulation, there is little doubt that the present regulatory burden should be reduced.
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Calabrese EJ, Hanekamp JC, Shamoun DY. The EPA Cancer Risk Assessment Default Model Proposal: Moving Away From the LNT. Dose Response 2018; 16:1559325818789840. [PMID: 30116166 PMCID: PMC6088500 DOI: 10.1177/1559325818789840] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 06/12/2018] [Accepted: 06/12/2018] [Indexed: 11/16/2022] Open
Abstract
This article strongly supports the Environmental Protection Agency proposal to make significant changes in their cancer risk assessment principles and practices by moving away from the use of the linear nonthreshold (LNT) dose-response as the default model. An alternate approach is proposed based on model uncertainty which integrates the most scientifically supportable features of the threshold, hormesis, and LNT models to identify the doses that optimize population-based responses (ie, maximize health benefits/minimize health harm). This novel approach for cancer risk assessment represents a significant improvement to the current LNT default method from scientific and public health perspectives.
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Affiliation(s)
- Edward J. Calabrese
- Department of Environmental Health Sciences, University of Massachusetts, Amherst, MA, USA
| | - Jaap C. Hanekamp
- Science Department, University College Roosevelt, Middelburg, The Netherlands
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Calabrese EJ. Was Muller's 1946 Nobel Prize research for radiation-induced gene mutations peer-reviewed? Philos Ethics Humanit Med 2018; 13:6. [PMID: 29875023 PMCID: PMC5991452 DOI: 10.1186/s13010-018-0060-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 05/17/2018] [Indexed: 05/31/2023] Open
Abstract
This historical analysis indicates that it is highly unlikely that the Nobel Prize winning research of Hermann J. Muller was peer-reviewed. The published paper of Muller lacked a research methods section, cited no references, and failed to acknowledge and discuss the work of Gager and Blakeslee (PNAS 13:75-79, 1927) that claimed to have induced gene mutation via ionizing radiation six months prior to Muller's non-data Science paper (Muller, Science 66(1699):84-87, 1927a). Despite being well acclimated into the scientific world of peer-review, Muller choose to avoid the peer-review process on his most significant publication. It appears that Muller's actions were strongly influenced by his desire to claim primacy for the discovery of gene mutation. The actions of Muller have important ethical lessons and implications today, when self-interest trumps one's obligations to society and the scientific culture that supports the quest for new knowledge and discovery.
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Affiliation(s)
- Edward J Calabrese
- Department of Environmental Health Sciences, School of Public Health and Health Sciences, University of Massachusetts, Morrill I, N344, Amherst, MA, 01003, USA.
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Calabrese EJ, Iavicoli I, Calabrese V, Cory-Slechta DA, Giordano J. Elemental mercury neurotoxicity and clinical recovery of function: A review of findings, and implications for occupational health. ENVIRONMENTAL RESEARCH 2018; 163:134-148. [PMID: 29438899 DOI: 10.1016/j.envres.2018.01.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 01/16/2018] [Accepted: 01/17/2018] [Indexed: 06/08/2023]
Abstract
This paper assessed approximately 30 studies, mostly involving occupationally exposed subjects, concerning the extent to which those who developed elemental mercury (Hg)-induced central and/or peripheral neurotoxicities from chronic or acute exposures recover functionality and/or performance. While some recovery occurred in the vast majority of cases, the extent of such recoveries varied considerably by individual and endpoint. Factors accounting for the extensive inter-individual variation in toxicity and recovery were not specifically assessed such as age, gender, diet, environmental enrichment, chelation strategies and dose-rate. While the data indicate that psychomotor endpoints often show substantial and relatively rapid (i.e., 2-6 months) recovery and that neuropsychological endpoints display slower and less complete recovery, generalizations are difficult due to highly variable study designs, use of different endpoints measured between studies, different Hg exposures based on blood/urine concentrations and Hg dose-rates, the poor capacity for replicating findings due to the unpredictable/episodic nature of harmful exposures to elemental Hg, and the inconsistency of the initiation of studies after induced toxicities and the differing periods of follow up during recovery periods. Finally, there is strikingly limited animal model literature on the topic of recovery/reversibility of elemental Hg toxicity, a factor which significantly contributes to the overall marked uncertainties for predicting the rate and magnitude of recovery and the factors that affect it.
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Affiliation(s)
- Edward J Calabrese
- Department of Environmental Health Sciences, University of Massachusetts, Morrill I, N344, Amherst, MA 01003, USA.
| | - Ivo Iavicoli
- Department of Public Health, University of Naples Federico II, Via S. Pansini 5, Naples 80131, Italy.
| | - Vittorio Calabrese
- Department of Biomed & Biotech Sciences, School of Medicine, University of Catania, Via Santa Sofia 97, Catania 95125, Italy.
| | - Deborah A Cory-Slechta
- Environmental Medicine, Pediatrics & Public Health Sciences, University of Rochester School of Medicine, Rochester, NY 14642, USA.
| | - James Giordano
- Department of Neurology and Biochemistry, and Neuroethics Studies Program-Pellegrino Center for Clinical Bioethics, Georgetown University Medical Center, Washington, D.C. 20057, USA.
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Oakley PA, Harrison DE. Radiophobia: 7 Reasons Why Radiography Used in Spine and Posture Rehabilitation Should Not Be Feared or Avoided. Dose Response 2018; 16:1559325818781445. [PMID: 30013456 PMCID: PMC6043928 DOI: 10.1177/1559325818781445] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 05/04/2018] [Accepted: 05/15/2018] [Indexed: 12/21/2022] Open
Abstract
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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Averbeck D, Salomaa S, Bouffler S, Ottolenghi A, Smyth V, Sabatier L. Progress in low dose health risk research. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2018; 776:46-69. [DOI: 10.1016/j.mrrev.2018.04.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 04/11/2018] [Accepted: 04/12/2018] [Indexed: 12/11/2022]
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Calabrese EJ. The Mistaken Birth and Adoption of LNT: An Abridged Version. Dose Response 2017; 15:1559325817735478. [PMID: 29051718 PMCID: PMC5637971 DOI: 10.1177/1559325817735478] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 08/22/2017] [Indexed: 11/16/2022] Open
Abstract
The historical foundations of cancer risk assessment were based on the discovery of X-ray-induced gene mutations by Hermann J. Muller, its transformation into the linear nonthreshold (LNT) single-hit theory, the recommendation of the model by the US National Academy of Sciences, Biological Effects of Atomic Radiation I, Genetics Panel in 1956, and subsequent widespread adoption by regulatory agencies worldwide. This article summarizes substantial recent historical revelations of this history, which profoundly challenge the standard and widely acceptable history of cancer risk assessment, showing multiple significant scientific errors and incorrect interpretations, mixed with deliberate misrepresentation of the scientific record by leading ideologically motivated radiation geneticists. These novel historical findings demonstrate that the scientific foundations of the LNT single-hit model were seriously flawed and should not have been adopted for cancer risk assessment.
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Affiliation(s)
- Edward J. Calabrese
- Department of Environmental Health Sciences, School of Public Health and Health Sciences, University of Massachusetts, Morrill I, Amherst, MA, USA
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Calabrese EJ. Flaws in the LNT single-hit model for cancer risk: An historical assessment. ENVIRONMENTAL RESEARCH 2017; 158:773-788. [PMID: 28756009 DOI: 10.1016/j.envres.2017.07.030] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 07/13/2017] [Accepted: 07/14/2017] [Indexed: 05/10/2023]
Abstract
The LNT single-hit model was derived from the Nobel Prize-winning research of Herman J. Muller who showed that x-rays could induce gene mutations in Drosophila and that the dose response for these so-called mutational events was linear. Lewis J. Stadler, another well-known and respected geneticist at the time, strongly disagreed with and challenged Muller's claims. Detailed evaluations by Stadler over a prolonged series of investigations revealed that Muller's experiments had induced gross heritable chromosomal damage instead of specific gene mutations as had been claimed by Muller at his Nobel Lecture. These X-ray-induced alterations became progressively more frequent and were of larger magnitude (more destructive) with increasing doses. Thus, Muller's claim of having induced discrete gene mutations represented a substantial speculative overreach and was, in fact, without proof. The post hoc arguments of Muller to support his gene mutation hypothesis were significantly challenged and weakened by a series of new findings in the areas of cytogenetics, reverse mutation, adaptive and repair processes, and modern molecular methods for estimating induced genetic damage. These findings represented critical and substantial limitations to Muller's hypothesis of X-ray-induced gene mutations. Furthermore, they challenged the scientific foundations used in support of the LNT single-hit model by severing the logical nexus between Muller's data on radiation-induced inheritable alterations and the LNT single-hit model. These findings exposed fundamental scientific flaws that undermined not only the seminal recommendation of the 1956 BEAR I Genetics Panel to adopt the LNT single-hit Model for risk assessment but also any rationale for its continued use in the present day.
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Affiliation(s)
- Edward J Calabrese
- Department of Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA 01003, USA.
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Jargin SV. Re: The high price of public fear of low-dose radiation. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2017; 37:797-799. [PMID: 28675752 DOI: 10.1088/1361-6498/aa7c69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Affiliation(s)
- Sergei V Jargin
- People's Friendship University of Russia, Clementovski per 6-82, 115184 Moscow, Russia
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Calabrese EJ. Obituary notice: LNT dead at 89 years, a life in the spotlight. ENVIRONMENTAL RESEARCH 2017; 155:276-278. [PMID: 28259091 DOI: 10.1016/j.envres.2017.02.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 02/21/2017] [Accepted: 02/24/2017] [Indexed: 06/06/2023]
Abstract
Considerable recent findings have revealed that the linear dose response for cancer risk assessment has not only outlived its utility in predicting risk but is based on a flawed scientific foundation. The present article characterizes this demise of a key concept of environmental risk assessment, in the framework of a figurative obituary of a long-lived concept that has poorly served society. This obituary is intended to illustrate an integrated mix of poignant and improper historical judgments that led to both the acceptance and ultimately the demise of this once intellectually facile and nearly universally accepted concept.
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Affiliation(s)
- Edward J Calabrese
- Department of Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA 01003, USA.
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