The first international workshop on Systems Radiation Biology: a new approach to solve old questions

Abstract

Ionizing radiation is ubiquitous and primordial; every living being has always been and will always be exposed to it from natural and man-made sources. Alpha and beta particles, gamma rays, neutrons and muons penetrate our body every second, and life has evolved under this environmental background condition. It is well known that acute irradiation with medium to high doses, i.e. far above the natural level, can cause negative physical health eVects in humans, animals and plants. At low doses of the order of the annual natural exposure, real, potential and perceived irradiations can deWnitely lead to observable mental and social health eVects. Thus, ionizing radiation is one of the few agents capable of aVecting all three aspects of human well-being considered by the World Health Organization. Whether or not small doses can also physically aVect human health is still an open scientiWc question. This has far-ranging consequences in the public attitude, e.g. towards facilities of the nuclear energy cycle and related political decisions. Finding new scientiWc approaches to tackle this old question has been the main aim of the First International Workshop on Systems Radiation Biology, which took place at the GSF-National Research Center for Environment and Health (its new name as of 1 January 2008 is Helmholtz Zentrum Munchen, German Research Center for Environmental Health) in Neuherberg near Munich, from 14 to 16 Febuary 2007. About 80 scientists from 13 countries exchanged and discussed their experience with the research strategy of Systems Biology in their various Welds. In the context of the workshop, “Systems Biology” (SB) is considered to study the various relevant processes and interactions between the components of a complex biological system, and how these give rise to the function, behaviour and reactions of that system after a disturbance. SB is characterized by cycles of (a) theory, (b) in silico modelling and (c) experiments, with the goal to quantitatively describe biological systems (e.g. cell, organs, etc.) and their behaviour. Useful SB experiments and models should in principle aim to provide (a) system-wide and (b) quantitative information that would allow construction and testing of explanatory and generalizing mathematical models to describe the behaviour of biological systems. Only with the help of such approved models, predictions can be made on the general or special behaviour of a living organism, including parameters, variables, etc. beyond the previous experimental evidence. However, presently there are several severe theoretical and experimental problems to identify and include—on a horizontal level—a suYcient number of subsystems (e.g. neighbouring cells) in a theoretical or experimental study. Additionally, it is also diYcult to identify and include them on a vertical level derived (a) from relevant molecules, (b) from their response and behaviour in cell compartments, (c) the fates of these cells, (d) the behaviour of a few cells in terms of the resulting consequences for the whole organ (remember, for example, that each single cell within the lung, which breathes to the beneWt of organismic oxygenation, does not breathe, as was pointed out by M.-H. Barcellos-HoV at the workshop), and (e) from the consequences which might Wnally determine the health status (e.g. free from cancer) of the whole organism. The biochemical and biophysical dynamic networks involved [1] are extremely complex and largely uncharacterized quantitatively. This is in part because of their natural H. G. Paretzke (&) Institute of Radiation Protection, Helmholtz Zentrum Munchen, German Research Center for Environmental Health, Ingolstadterstr.1, 85764, Neuherberg, Germany e-mail: paretzke@helmholtz-muenchen.de