46 research outputs found
Radiation Hormesis: Historical Perspective and Implications for Low-Dose Cancer Risk Assessment
No full textCurrent guidelines for limiting exposure of humans to ionizing radiation are based on the linear-no-threshold (LNT) hypothesis for radiation carcinogenesis under which cancer risk increases linearly as the radiation dose increases. With the LNT model even a very small dose could cause cancer and the model is used in establishing guidelines for limiting radiation exposure of humans. A slope change at low doses and dose rates is implemented using an empirical dose and dose rate effectiveness factor (DDREF). This imposes usually unacknowledged nonlinearity but not a threshold in the dose-response curve for cancer induction. In contrast, with the hormetic model, low doses of radiation reduce the cancer incidence while it is elevated after high doses. Based on a review of epidemiological and other data for exposure to low radiation doses and dose rates, it was found that the LNT model fails badly. Cancer risk after ordinarily encountered radiation exposure (medical X-rays, natural background radiation, etc.) is much lower than projections based on the LNT model and is often less than the risk for spontaneous cancer (a hormetic response). Understanding the mechanistic basis for hormetic responses will provide new insights about both risks and benefits from low-dose radiation exposure
Hormesis, Adaptive Epigenetic Reorganization, and Implications for Human Health and Longevity
No full textHormesis is a common phenomenon in a number of biomedical areas. However, the basic nature of this phenomenon remains largely unknown. Therefore, significant uncertainty is inevitable in attempts to apply hormesis as a pro-health and anti-aging tool. Evidence supporting that hormetic-like effects may be the result of a generalized whole-organism adaptive epigenetic response is reviewed. Specific hormesis-inducing interventions during development would allow to achieve an optimal balance between activation and repression of various genes and thus to prevent age-related degenerative diseases and slow aging. The reasons that oscillating temperature mild stress could potentially be used for human application are discussed
Living Long and Aging Well: Are Lifestyle Factors the Epigenetic Link in the Longevity Phenotype
No full textSocietal and medical advances have extended life expectancy for people globally. Despite the significance of wellbeing for everyone, the challenge for medicine, society, and governments is to make the added years as healthy and productive as possible. People who age exceptionally well interest us. Current ninety-year-olds and centenarians are the survivors of their generation and are the fastest growing population group in Europe and the developed world. We want to know what gives them their determination to go forward; how have they remained healthy and escaped the dangers of illness and degenerative disease throughout their long lives? This chapter discusses some lifestyle and behavioral factors that associate with good quality longevity and describes links and evidence with known epigenetic mechanisms. It seems possible that exceptional ninety-year-olds and centenarians may have actively or intuitively adopted a range of behaviors and lifestyles that have contributed, through epigenetic mechanisms, to their aging-well-phenotype
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Hormesis and adaptive epigenetic reorganization
No full textHormesis is a common phenomenon in a number of biomedical areas. However, the basic nature of this phenomenon remains largely unknown. Therefore, significant uncertainty is inevitable in attempts to apply hormesis as a pro-health and anti-aging tool. Evidence supporting that hormetic-like effects may be the result of a generalized wholeorganism adaptive epigenetic response is reviewed. Specific hormesis-inducing interventions during development would allow to achieve an optimal balance between activation and repression of various genes and thus to prevent age-related degenerative diseases and slow aging. The reasons that oscillating temperature mild stress could potentially be used for human application are discussed
Recommended from our members
Radiation hormesis: historical perspective
No full textCurrent guidelines for limiting exposure of humans to ionizing radiation are based on the linear-no-threshold (LNT) hypothesis for radiation carcinogenesis under which cancer risk increases linearly as the radiation dose increases. With the LNT model even a very small dose could cause cancer and the model is used in establishing guidelines for limiting radiation exposure of humans. A slope change at low doses and dose rates is implemented using an empirical dose and dose rate effectiveness factor (DDREF). This imposes usually unacknowledged nonlinearity but not a threshold in the dose-response curve for cancer induction. In contrast, with the hormetic model, low doses of radiation reduce the cancer incidence while it is elevated after high doses. Based on a review of epidemiological and other data for exposure to low radiation doses and dose rates, it was found that the LNT model fails badly. Cancer risk after ordinarily encountered radiation exposure (medical X-rays, natural background radiation, etc.) is much lower than projections based on the LNT model and is often less than the risk for spontaneous cancer (a hormetic response). Understanding the mechanistic basis for hormetic responses will provide new insights about both risks and benefits from low-dose radiation exposure
