This review will be concerned with the acute effects of high energy radia tions on mammalian systems. Its purpose is twofold; to delineate many of the recent papers in this areal and to place the more important contributions in some perspective to the over-all physiology of radiation injury. Complete coverage of radiation effects is not intended, owing to the vast literature and the consequent necessity of excluding many papers to conform to the allotted space.3 Several surveys of the more general aspects of radiation effects on liv ing systems have been presented recently (1 to 7); cellular (8, 9), embryo logiCal (10), and carcinogenic (11) actions of irradiation have also been cov ered. The extensive report of acute radiation injury in man resulting from accidental nuclear reactions should be consulted (12). These cases represent radiation injury not complicated by the effects of heat and blast.It is appropriate to say a word about trends in mammalian radiobiology by way of introduction. We may note an increasing interest in the more im mediate physical and chemical changes in irradiated tissue. Such endeavors have been greatly influenced by present concepts of the modes of energy transfer and the recognition that certain, apparently primary, events may be modified experimentally. Greatest attention continues to be focused, how ever, on the disordered physiology as manifested by effects on growing and developing systems generally and by pancytopenia, bleeding, inanition, in fection, altered immune reactions, and carcinogenesis, specifically. In this area, there is a growing awareness that injury and recovery may be influenced to a considerable extent by the physiological interplay in the organism as a whole.THE RADIATIONS While all of the ionizing radiations produce more or less similar biological effects, their efficiency can vary considerably, This depends apparently upon the energy absorption in space and time and also upon its distribution within the organism. For most effects, excluding those that are related pre sumably to very small volumes, biological effectiveness increases with in crease in linear ion density or, more appropriately, in linear energy transfer. Gray (13) has emphasized that the rapid variation of efficiency with ion 1 The survey of literature pertaining to this review covers the period from January, 1951 to June, 1953.2 The following abbreviations are used in this chapter: DNA (desoxyribonucleic acid); RNA (ribonucleic acid).3 This refers in particular to miscellaneous effects on skin, bone, gonads, and nervous system.
51Annu. Rev. Physiol. 1954.16:51-80. Downloaded from www.annualreviews.org by University of Laval on 07/11/14. For personal use only.Quick links to online content Further ANNUAL REVIEWS
