The prospective mathematical idea satisfying both radiation hormesis under low radiation doses and linear non-threshold theory under high radiation doses

Kino, Katsuhito

doi:10.1186/s41021-020-0145-4

Cited by 9 publications

(50 citation statements)

References 10 publications

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“…The theory of hormesis is still a theory [ 153 , 154 ]. Considerable further research is required to prove, disprove, or modify it.…”

Section: Discussionmentioning

confidence: 99%

Less Can Be More: The Hormesis Theory of Stress Adaptation in the Global Biosphere and Its Implications

Schirrmacher¹

2021

Biomedicines

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A dose-response relationship to stressors, according to the hormesis theory, is characterized by low-dose stimulation and high-dose inhibition. It is non-linear with a low-dose optimum. Stress responses by cells lead to adapted vitality and fitness. Physical stress can be exerted through heat, radiation, or physical exercise. Chemical stressors include reactive species from oxygen (ROS), nitrogen (RNS), and carbon (RCS), carcinogens, elements, such as lithium (Li) and silicon (Si), and metals, such as silver (Ag), cadmium (Cd), and lead (Pb). Anthropogenic chemicals are agrochemicals (phytotoxins, herbicides), industrial chemicals, and pharmaceuticals. Biochemical stress can be exerted through toxins, medical drugs (e.g., cytostatics, psychopharmaceuticals, non-steroidal inhibitors of inflammation), and through fasting (dietary restriction). Key-lock interactions between enzymes and substrates, antigens and antibodies, antigen-presenting cells, and cognate T cells are the basics of biology, biochemistry, and immunology. Their rules do not obey linear dose-response relationships. The review provides examples of biologic stressors: oncolytic viruses (e.g., immuno-virotherapy of cancer) and hormones (e.g., melatonin, stress hormones). Molecular mechanisms of cellular stress adaptation involve the protein quality control system (PQS) and homeostasis of proteasome, endoplasmic reticulum, and mitochondria. Important components are transcription factors (e.g., Nrf2), micro-RNAs, heat shock proteins, ionic calcium, and enzymes (e.g., glutathion redox enzymes, DNA methyltransferases, and DNA repair enzymes). Cellular growth control, intercellular communication, and resistance to stress from microbial infections involve growth factors, cytokines, chemokines, interferons, and their respective receptors. The effects of hormesis during evolution are multifarious: cell protection and survival, evolutionary flexibility, and epigenetic memory. According to the hormesis theory, this is true for the entire biosphere, e.g., archaia, bacteria, fungi, plants, and the animal kingdoms.

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“…The theory of hormesis is still a theory [ 153 , 154 ]. Considerable further research is required to prove, disprove, or modify it.…”

Section: Discussionmentioning

confidence: 99%

Less Can Be More: The Hormesis Theory of Stress Adaptation in the Global Biosphere and Its Implications

Schirrmacher¹

2021

Biomedicines

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“…With reference to a previous report [5], we defined the radiation dose as x, the cancer death rate as D(x), and the inhibition effect as R(x). The radiation dose at which R(x) reaches a maximum is defined as x 1 , the value of x for the local minimum of D(x) as x 2 , the value of x for the local maximum of D(x) as x 3 , and the other value of x where D has the same value as D(x 3 ) as x 4 .…”

Section: Equations and Graphsmentioning

confidence: 99%

“…The radiation dose at which R(x) reaches a maximum is defined as x 1 , the value of x for the local minimum of D(x) as x 2 , the value of x for the local maximum of D(x) as x 3 , and the other value of x where D has the same value as D(x 3 ) as x 4 . Therefore, such definitions lead the hormesis region to x 3 -x 4 mSv [5].…”

Section: Equations and Graphsmentioning

confidence: 99%

“…On the other hand, many studies have described radiation hormesis theory, whereby radiation is thought to have beneficial effects on health [2][3][4]. If the indeterminacy of the LNT theory under 100 mSv were combined with the assumption of radiation hormesis (Figure 1B), a theory satisfying both radiation hormesis at low doses and the LNT theory at high doses could be suggested [5]. Herein, based on a previous theory [5], we aimed to obtain an equation to give the maximum hormesis region while satisfying the LNT theory at ≥100 mSv and to calculate the dose that maximizes the inhibitor factors.…”

Section: Introductionmentioning

confidence: 99%

“…If the indeterminacy of the LNT theory under 100 mSv were combined with the assumption of radiation hormesis (Figure 1B), a theory satisfying both radiation hormesis at low doses and the LNT theory at high doses could be suggested [5]. Herein, based on a previous theory [5], we aimed to obtain an equation to give the maximum hormesis region while satisfying the LNT theory at ≥100 mSv and to calculate the dose that maximizes the inhibitor factors. Next, from existing reports, we aimed to search candidate inhibitor factors whose quantities depend on the radiation dose with fluctuations in a mountain-like shape.…”

Section: Introductionmentioning

confidence: 99%

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Considering Existing Factors That May Cause Radiation Hormesis at <100 mSv and Obey the Linear No-Threshold Theory at ≥100 mSv

et al. 2021

Self Cite

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The linear no-threshold (LNT) theory describes the linear relationship between a radiation dose and its effects. However, whether the linear relationship is maintained at low radiation doses has yet to be determined. Many previous studies support the radiation hormesis theory, which states that radiation has beneficial effects on health. In this viewpoint, we propose a mathematical function fitted to a model consistent with both the LNT at ≥100 mSv and radiation hormesis theories at <100 mSv, and the model requires a factor whose amount or activity takes a mountain-like shape versus the radiation dose and have one maximum value at 40.9 mSv. We searched a wide range of factors with these features based on searches on PubMed, and then evaluated whether these factors were suitable candidates consistent with both the LNT and radiation hormesis theories. Our consideration indicated that these factors did not completely follow the equation suggested at this time. Of course, other theories do not deny that these factors are involved in hormesis. However, based on our theory, still unknown factors may be involved in radiation hormesis, and then such unknown factors which are activated at <100 mSv should be searched.

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Radiation and chemical induced genomic instability as a driver for environmental evolution

Mothersill

Rusin

Elliott³

et al. 2021

Genome Stability

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The prospective mathematical idea satisfying both radiation hormesis under low radiation doses and linear non-threshold theory under high radiation doses

Cited by 9 publications

References 10 publications

Less Can Be More: The Hormesis Theory of Stress Adaptation in the Global Biosphere and Its Implications

Less Can Be More: The Hormesis Theory of Stress Adaptation in the Global Biosphere and Its Implications

Considering Existing Factors That May Cause Radiation Hormesis at <100 mSv and Obey the Linear No-Threshold Theory at ≥100 mSv

Radiation and chemical induced genomic instability as a driver for environmental evolution

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