In bacteria, there is evidence that a damage inducible repair response system known as the adaptive response exists since pretreatment with low doses of a simple monofunctional alkylating agent leads to a decrease in both the lethal and mutagenic effects of a subsequent challenge dose of the agent. The evidence for an analagous system in mammalian cells has proved to be inconsistent to date. The induction of chromosome repair mechanisms in human cells by low-dose radiation from tritiated thymidine has been shown to make the cells refractory to the induction of chromosome aberrations by X-rays. The present communication investigates the induction of an adaptive response in human lymphocytes from four donors and V79 cells using SCE and mutation as endpoints and MNNG and MNU for the adapting and challenging treatment. It is clear that a reproducible model of the adaptive response in human lymphocytes is difficult to establish because of the variability between different donors and different culture times. In V79 cells, assays with much larger cell numbers are required to detect a reproducible response with such small changes in mutant frequency. To demonstrate an adaptive response conclusively in mammalian cells will probably require the use of more sensitive experimental protocols and alternative methods of administration of adaptive doses of mutagen.

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1983 376 pp $29.95 (Cloth).The newest work by Olaf Helmer, best known for the development of the Delphi procedure, is an interesting book that should be particularly useful to those not already familiar with the subject of futures research. More than three-fourths of the material in this book has been published before in articles and documents authored or co-authored by Helmer during the last forty years or so. As a result, the discussion is sprinkled with references that are, by now, outdated However, the liberal attention given to certain very current issues, such as the impact of automation on our world and on our research about our world, keeps the tone of the overall discussion up to date and relevant.Throughout the book Helmer distinguishes between &dquo;exact&dquo; and &dquo;inexact&dquo; sciences, and repeatedly emphasizes that these distinctions do not necessarily coincide with the boundaries of the physical and social sciences. Rather than being peculiar to specific fields, applications of exact science are usually found at the theoretical, abstract core of a discipline, and become &dquo;less exact&dquo; in efforts to relate the discipline to &dquo;the complexities of the real world &dquo; Acknowledging, however, that planning (and other social science) research lags behind (or contains relatively fewer areas of &dquo;exact&dquo; applications than) much of the physical sciences due to the complexity of the issues and a relative lack of a theory base, Helmer proposes a possible aid in the form of developing a new &dquo;social technology.&dquo; Advocating the use of those methods generally referred to as operations research, and endorsing Bertrand de Jouvenel's suggestion for institutionalizing futures research, Helmer proceeds to recommend philosophy and methods that he views as maximally enabling the progress of truly interdisciplinary research aimed at consciously and deliberately planning for a better future In order to obtain predictions and forecasts for the purpose of future policy development, decision-makers working in the environment of an inexact science often turn to experts to seek advice and opinions. Rather than being dismayed at the potential threats to scientific objectivity in such approaches, Helmer suggests that a large part of the methodology needed by futures researchers should involve systematic procedures for the objective and intelligent use of expert human judgments. He reasons that the time is right for the development of such methods, since we can now rapidly compile an abundance of potentially useful information about world problems, and finally have full access to the power of the electronic age to help us harness the information The first seven chapters of Looking Forward deal, either directly or indirectly, with the methodology of the use of experts. Helmer provides descriptions and examples of the use of Delphi, cross-impact analysis, modeling, and gaming and simulation. He argues for the use of &dquo;pseudo-experimentation&dquo; m the exploration of socio-economic problem...