Physical And Chemical Mechanisms In Molecular Radiation Biology

The fundamental understanding of the production of biological effects by ionizing radiation may well be one of the most important scientific objectives of mankind; such understanding could lead to the effective and safe utilization of the nuclear energy option. In addition, this knowledge will be of immense value in such diverse fields as radiation therapy and diagnosis and in the space program. To achieve the above stated objective, the U. S. Department of Energy (DOE) and its predecessors embarked upon a fundamental interdisciplinary research program some 35 years ago. A critical component of this program is the Radiological and Chemical Physics Program (RCPP). When the RCPP was established, there was very little basic knowledge in the fields of physics, chemistry, and biology that could be directly applied to understanding the effects of radiation on biological systems. Progress of the RCPP program in its first 15 years was documented in the proceedings of a conference held at Airlie, Virginia, in 1972. At this conference, it was clear that considerable progr:ess had been made in research on the physical and chemical processes in well-characterized systems that could be used to understand biological effects. During this period of time, most physical knowledge was obtained for the gas phase because the technology and instru mentation had not progressed to the point that measurements could be made in liquids more characteristic of biological materials.

Advances in Radiation Biology, Volume 9, provides an overview of the state of knowledge in radiation biology. The book contains nine chapters and begins with a study on the ways in which physical and chemical agents might trigger "regulatory dysfunction" and how these agents might interact with each other. This is followed by separate chapters on the mechanisms underlying changes in vascular function after doses of radiation in the therapeutic range and their role in the development of late effects in normal tissues; the future of hypoxic cell sensitizers in the clinical setting; DNA strand break formation by ionizing radiation; and major pathways which result in radiation-induced loss of cellular proliferative capacity. Subsequent chapters deal with the solid-state radiation chemistry of DNA; radiosensitivity of proliferating mammalian cells; the use of microwave/radiofrequency energy cancer treatment; and the decline of basic radiobiology.

Advances in Radiation Biology, Volume 2, reflects a continuing effort to provide wide-ranging analyses of progress in various phases of radiation research. The articles cover a spectrum of topics varying from the initial physical events which allow us to discriminate color, to the chemical and biological processes which determine the extent and permanence of radiation damage, and finally to the role of genetic control and damage in determining the fate of irradiated cells. The basic emphasis of the articles also varies. In some, the main attempt is to review extensively the available data so as to evaluate the possible contributions of various mechanisms to a given phenomenon. One article is devoted an evaluation of one physical approach which appears to be a promising way of understanding color perception. These different treatments should be of value not only to the researcher but also to the student, inasmuch as each approach is invariably dictated by the state of the art in the area being covered.

There can hardly be any doubt that radiation will continue to be an im portant factor in our lives. Present and future advances in atomic tech nology urgently require further work on research and development in the field of radiation biology if the maximum benefit is to be obtained at minimal risk from the various kinds of radiation that form a major by product of nuclear processes. Consequently, it is also necessary to prepare students and younger scientists for doing such work. The present book originates from teaching experience gained in lectures, seminars, and discussion groups started by the undersigned in 1957 and more recently held together with Drs. Dertinger and Jung. The friendly comments given to the German edition made us feel that it might be worth while to put the results of our efforts at the disposal of those to whom English is more familiar. In agreement with the view, based on well-known facts, that most if not aIl of the more striking practical achievements have resulted from patient and careful investigations into some basic problem, the book aims at introducing the reader to the methods of thought and experiment used in molecular radiation biology as weIl as to the results obtained thereby.

The book is concerned with features analysis of radiation damage to living matter at different levels of its organisation, beginning from the molecular level. The general theory of the mechanisms of biological action of radiation based on four logically connected principles of radiation biology is presented for the first time. The book contains abundant material on primary and secondary processes of the response of living systems to radiation, the mechanisms of direct and indirect action of radiation through radiolysis of water and lipids; a detailed consideration of the theory of targets (DNA and biological membranes) and the problems of high- and low-dose irradiation in the context of present-day. The systemic response of the cell to irradiation (oxidative stress, endogenous background radioresistance, damage and repair of biological membranes and DNA, systemic protection against radiation) is approximated. Presentation of these important problems is preceded by an up-to-date evaluation of some aspects regarding dosimetry of ionising radiation.