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Radiation, Ecology And The Invalid Lnt Model: The Evolutionary Imperative, Peter A Parson
Radiation, Ecology And The Invalid Lnt Model: The Evolutionary Imperative, Peter A Parson
Dose-Response: An International Journal
Metabolic and energetic efficiency, and hence fitness of organisms to survive, should be maximal in their habitats. This tenet of evolutionary biology invalidates the linear-nothreshold (LNT) model for the risk consequences of environmental agents. Hormesis in response to selection for maximum metabolic and energetic efficiency, or minimum metabolic imbalance, to adapt to a stressed world dominated by oxidative stress should therefore be universal. Radiation hormetic zones extending substantially beyond common background levels, can be explained by metabolic interactions among multiple abiotic stresses. Demographic and experimental data are mainly in accord with this expectation. Therefore, non-linearity becomes the primary model for …
Stress Response Mechanisms: From Single Cells To Multinational Organizations, Richard J Pech
Stress Response Mechanisms: From Single Cells To Multinational Organizations, Richard J Pech
Dose-Response: An International Journal
Can a literal comparison be made between biological phenomena in organisms and phenomena in human organizations? The evidence provided by simplified but useful examples appears to suggest that a phenomenon simulating hormesis can and does occur in organizational contexts. Similarities between stress response behaviors of organisms and stress response behaviors in organizations are discussed. Cellular stress response mechanisms stimulate and repair, as well as defend the organism against further attacks. Organizational hormesis describes actions that stimulate the organization by increasing its focus and protecting it against future attacks. The common aim for the organism as well as the organization is …
The Unexpected Anabolic Phenotype And Extended Longevity Of Skin Fibroblasts After Chronic Glucocorticoid Excess, Harris Pratsinis, Stylianos Tsagarakis, Irene Zervolea, Dimitri Stathakos, Nikos Thalassinos, Dimitris Kletsas
The Unexpected Anabolic Phenotype And Extended Longevity Of Skin Fibroblasts After Chronic Glucocorticoid Excess, Harris Pratsinis, Stylianos Tsagarakis, Irene Zervolea, Dimitri Stathakos, Nikos Thalassinos, Dimitris Kletsas
Dose-Response: An International Journal
Intense stress can challenge tissue homeostasis and accelerate the ageing process. However, several lines of evidence indicate that repeated mild stresses can have beneficial and even life-prolonging effects. Hypersecretion of glucocorticoids (GC) represents the major hormonal response to stress. Besides its life-sustaining role, GC excess, usually due to several side-effects that promote a “catabolic” phenotype, can be detrimental for several tissues. Cushing’s syndrome patients are characterized by chronic endogenous GC excess and consequently at the time of diagnosis they have an atrophic elderly-like skin. Interestingly, when Cushing’s syndrome fibroblasts were removed from the high-GC milieu in vivo and cultured in …
Detecting Causal Nonlinear Exposure-Response Relations In Epidemiological Data, Louis Anthony Cox Jr
Detecting Causal Nonlinear Exposure-Response Relations In Epidemiological Data, Louis Anthony Cox Jr
Dose-Response: An International Journal
The possibility of hormesis in individual dose-response relations undermines traditional epidemiological criteria and tests for causal relations between exposure and response variables. Non-monotonic exposure-response relations in a large population may lack aggregate consistency, strength, biological gradient, and other hallmarks of traditional causal relations. For example, a u-shaped or n-shaped curve may exhibit zero correlation between dose and response. Thus, possible hormesis requires new ways to detect potentially causal exposure-response relations. This paper introduces information-theoretic criteria for identifying potential causality in epidemiological data that may contain nonmonotonic or threshold dose-response nonlinearities. Roughly, exposure variable X is a potential cause of response …
Radon Treatment Controversy, Zygmunt Zdrojewicz, Jadwiga (Jodi) Strzelczyk
Radon Treatment Controversy, Zygmunt Zdrojewicz, Jadwiga (Jodi) Strzelczyk
Dose-Response: An International Journal
In spite of long traditions, treatments utilizing radon-rich air or water have not been unequivocally embraced by modern medicine. The objective of this work is to examine factors that contribute to this continuing controversy. While the exact mechanism of radon’s effect on human body is not completely understood, recent advances in radiobiology offer new insights into biochemical processes occurring at low-level exposures to ionizing radiation. Medical evidence and patients’ testimonials regarding effectiveness of radon spa treatments of various ailments, most notably rheumatoid arthritis are accumulating worldwide. They challenge the premise of the Linear-No-Threshold (LNT) theory that the dose-effect response is …