Radiation-Induced Processes of Adaptation

Research by statistical modelling

verfasst von: Victoria L. Korogodina, Boris Florko, Ludmila P. Osipova

Verlag: Springer Netherlands

Enthalten in: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik"

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Über dieses Buch

In recent decades radiobiologists’ efforts have been directed at identifying the mechanisms of radiation effects; the general mechanisms have since been studied extensively. This book describes and analyzes radiation-induced adaptation as processes produced in cells, tissues, and populations. This viewpoint helps to understand the nature and factors of induced processes, to determine the characteristics of observed radiation effects and their limitations. The investigations presented here were founded on proper lab experiments, ecological studies of plant population growth near an operating nuclear power plant and a thorough epidemiological examination of human populations living in territories polluted fifty years ago, as well as on relevant published data. This research demonstrates the radiation-induced adaptation processes that continue even when the radiation itself is no longer at a critical background level. The investigations utilized the method of statistical modeling on the basis of distributions on the number of abnormalities. This method allows us to investigate the processes induced by low-dose factors when accompanied by Darwinian selection in different systems; the distribution parameters can then be used to study the characteristics of adaptation processes and system resistance. The consequences of background-level radiation continue to provoke debate, and the mathematical bases of the adaptation model are shown, while due consideration is paid to the components of adaptation: instability, selection, and proliferation. The book will be especially useful to specialists in radiation pollution, ecology, epidemiology, and radiology for studies of radiation-induced processes; the method presented here can also be adapted to investigate low-dose effects in other fields. In addition, the book presents a number of reviews in the fields of radiation biology, including pioneering investigations in Russia which were previously unavailable to Western scientists.

Inhaltsverzeichnis

Frontmatter

Chapter 1. Introduction

Abstract

In recent times, many researchers have studied general mechanisms of low-dose radiation effects and have published descriptions of a wide variety of radiation-polluted territories. However, there have not yet been enough analytic investigations of the processes of adaptation. The purpose of this book is to describe those processes of adaptation that are induced by the radiation factor in cells, tissues, and populations. They were examined through a method of statistical modelling that is suitable for analyzing those cases when the radiation factor is comparable with the background. Statistical modelling identifies the processes of the changes’ appearance with a statistical description of the fitted system structure on the number of changes. Statistical modelling is an instrument which separates reactions of resistant and sensitive subpopulations. This approach gives us an opportunity to calculate the risks of instability leading to both the accumulation of abnormalities and selection processes. Statistical modelling is a technique that can be successfully developed by investigators of low-dose effects in different fields.

Victoria L. Korogodina, Boris V. Florko, Ludmila P. Osipova

Chapter 2. Disturbance of Hereditary Material Reserves Is the Main Instrument of Stress

Abstract

This review presents data on the low-dose radiation effects and their mathematical models. Its purpose is to demonstrate that radiation stress leads to processes of instability that can be revealed as different phenomena. The phenomena of radioadaptation, nonlinear response induced by low-dose irradiation, hormetic effect, and continued instability across generations, and stimulation of proliferation are considered. Our special interest is the investigation of the bystander effect which clarified some of these phenomena. The regularities of the bystander effect, genomic and transgenerational instability are considered. The modelling of these radiation effects is discussed: the models offered by Yu.G. Kapultsevich (probabilistic), D.J. Brenner et al. (“Bystander and Direct”), H. Nikjoo and I.K. Khvostunov (Diffusion model), and B.E. Leonard (“Microdose Model”) are presented. The investigations of Russian scientists and the Timofeeff-Ressovsky school are presented as being of special interest to Western scientists owing to this information not having been published in the West due to the cold war.

Victoria L. Korogodina, Boris V. Florko, Ludmila P. Osipova

Chapter 3. Excursus on Statistical Modelling for Population Biology. Statistical Solution of Some Radiobiological Tasks

Abstract

The consequences of background-level radiation often provoke debates, and here statistical ideas and their mathematical basis are considered in view of adaptation processes. Statistical modelling presents the data of investigations in the form of frequency function of events occurrence that allows studying the laws and regularities of respective probability processes. It is qualified to investigate the processes induced by the low factors and accompanied by Darwinian selection in different systems. Three themes are discussed: (1) A geometric model of adaptation, (2) Research of the biological communities’ structure, and (3) A statistical view of the cytogenetic investigations of instabilities. The first and second topics present development of statistical ideas on live systems under environmental conditions. The last part is devoted to models of appearance of cells with abnormalities, chromosomal abnormalities in cells, proliferated cells and interrelation between the distributions on the number and frequency of abnormalities. We can assume that a strong factor leads to the same laws of regulated abundance of the communities of species and cell population.

Victoria L. Korogodina, Boris V. Florko, Ludmila P. Osipova

Chapter 4. Non-linearity Induced by Low-Dose Rates Irradiation. Lab Experiments on Pea Seeds

Abstract

General regularities of low dose-rate radiation effects were determined on plant seeds in laboratory experiments. Three groups of seeds were tested: young, old, and heat-stressed because aging and high temperature are the usual natural factors. Statistical modelling has shown that the adaptation processes have three components: primary injuring, late damaging, and selection, which is more intensive in the sensitive subpopulation of seeds. The relationship between inter- and intracellular processes was analyzed. The combination of radiation and heat stresses dramatically increases late damaging and selection at non-optimal temperatures which do not exceed the norm limits. This approach allows one to estimate the risks of instabilities accompanied by the accumulation of abnormalities, selection, and death of seedlings.

Victoria L. Korogodina, Boris V. Florko, Ludmila P. Osipova

Chapter 5. Adaptation and Genetic Instability in Ecology. Study of the Influence of Nuclear Station Fallout on Plant Populations

Abstract

Here, the ecological investigations which were performed by statistical modelling are presented. The aim of these investigations was to study the effects of the fallout of operating nuclear station which do not exceed the background (the annual γ-radiation dose rates are ≈0.10–0.15 μSv/h) on plantain populations growing in the 30-km zone of the station. The statistical modelling was performed to study cells’ and chromosomes’ instability, cells’ proliferation in root meristem of seedlings, selection processes, and their dependence on radiation fallout and seeds’ sensitivity. This approach divides the tested population into resistant and sensitive fractions which are Poisson and geometric distributed on the number of abnormalities. This finding allowed us (1) to identify the radiation-induced effect and to reject the hypothesis that its consequences were caused by chemical pollution; (2) to estimate risks of instability and selection as well as stimulation of cells’ proliferation which are components of the adaptation processes; (3) to study their regularities for both resistant and sensitive subpopulations; and (4) to demonstrate that risks of adaptation processes dramatically increase with additional synergic factors, such as in a hot summer when survival of seeds falls to 20–30 %. We conclude that nuclear station fallout influences significantly the seeds’ survival and chromosomal instability in meristem of seedlings especially in hot summer. The radiation-induced processes lead to changes of the previous genotype on the adaptive one. The other conclusion is decreased numbers of some species right up to their disappearance.

Victoria L. Korogodina, Boris V. Florko, Ludmila P. Osipova

Chapter 6. Instability Process Across Generations. Consequences of Nuclear Test Fallout for Inhabitants

Abstract

The radiation effects on the human populations living in regions distant from the sites of nuclear explosions that took place in the middle of the previous century are analyzed. The statistical modelling was performed to study the occurrence frequency of abnormal lymphocyte cells among the proliferated ones in the blood of individuals living in the Yamalo-Nenets autonomous district (North Siberia), and settlements in Maloe Goloustnoe and Listvyanka (Pribaikal’e). Four generations of individuals were tested. It was shown that the geometric model component corresponds to the individuals with bad activated lymphocyte cells, lymphocyte pool depletion, and increased mortality, and the Poisson model means accumulation of abnormal cells. The Poisson component was only revealed in younger generations and can be interpreted as “effect of youth.” The worst situation is observed in the Northern population, which can be expected due to Northern permafrost and the traditional food chain of “lichen-reindeer-man”. The influence of the radiochemical industry on the occurrence of multi-aberrant cells in the blood of its workers and the inhabitants of the town in which it operates was studied by the statistical modelling, with elevated chromosomal instability being found. We conclude that chromosomal instability induced by nuclear test fallout continued for four generations. It was shown that the Poisson sample mean decreased very slowly across a generation which disputes the opinion that reduction of cellular instability in youngsters in the previous investigations was based on the averaged values. In addition, aging and extreme conditions increase the risks of chromosomal instability and mortality.

Victoria L. Korogodina, Boris V. Florko, Ludmila P. Osipova

Chapter 7. Conclusion

Abstract

Here, we will summarize our knowledge of adaptation and chromosomal instability in terms of inter- and intracellular processes. This point of view presents these phenomena as a natural law regulating survival of organisms in their ecological niches. We emphasize the role of instability in providing the non-linearity characterizing low-radiation effects. Statistical modelling is considered as instrumental to the study of low-dose effects. Four issues will be discussed below: connection of adaptation with instability and selection processes, general features of adaptation and instability, consequences of low-radiation fallout for nature and humans, and how adaptation and instability processes can be described statistically.

Victoria L. Korogodina, Boris V. Florko, Ludmila P. Osipova

Chapter 8. Applications

Abstract

This chapter presents the approximations, calculations and methods that require the use of statistical modelling. Special attention is devoted to the analysis of chemical pollution near a nuclear power plant which can induce cell damages or imitate the dependence of the distribution parameters on the average daily fallout. Eight topics will be discussed: Methods of approximation; Approximations of pea seeds distributions on the number of cells with abnormalities irradiated in the laboratory; Sample of the calculation of the synergic coefficient; Approximations of distributions for plantain seeds growing near a nuclear power plant; Analysis of the correlations of seed mortality (1 − S) and parameters of the plantain seed distributions on the numbers of proliferated and abnormal cells with contamination of chemical pollutions in soil; Statistical modelling of the occurrence frequency of cells with abnormalities in blood lymphocytes of individuals.

Victoria L. Korogodina, Boris V. Florko, Ludmila P. Osipova

Backmatter

Titel: Radiation-Induced Processes of Adaptation
verfasst von: Victoria L. Korogodina
Boris Florko
Ludmila P. Osipova
Verlag: Springer Netherlands
Electronic ISBN: 978-94-007-6630-3
Print ISBN: 978-94-007-6629-7
DOI: https://doi.org/10.1007/978-94-007-6630-3