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Irradiation of whole blood with 137Cs gamma rays intensifies the oxidative burst. Oxidant production was used as an indicator of inflammatory cell reactions and was measured by luminol-amplified chemiluminescence after treatment with inflammatory activators including bacteria, the neutrophil taxin formyl-Met-Leu-Phe, the Ca2+ ionophore A23187, the detergent saponin, and the tumor promoter phorbol ester. The irradiation response is dose-dependent up to about 100 microGy, is detectable within minutes, persists at least 1 h, and is transmitted intercellularly by a soluble mediator. The response is completely inhibited by Ca2+ sequestration in the presence of A23187 or by adenosine, indicating its Ca2+ dependency, and by the phospholipase A2 blocker p-bromphenacyl bromide. However, inhibition by the cyclooxygenase blocker aspirin is sporadic or absent. Blood taken after diagnostic examination of lungs with X rays also exhibited intensified chemiluminescence. These reactions implicate a role for specific amplifying mediator pathways, especially metabolites of the arachidonic acid cascade, in the response: "damage and repair" to cells or DNA plays little or no role. Our results provide evidence for a new mechanism of radiation action with possible consequences for the homeostasis of reactions involving inflammation and second messengers in human health and early development.

The dynamic periphery of unstimulated, preaggregation, hunger-stage Dictyostelium discoideum amoebae was investigated by time-lapse videomicroscopy and digital image processing. Circular maps (i.e. of each of 360 radii around the cell transformed upon Cartesian coordinates) were constructed around the centroid of individual cell images and analysed in time series. This novel technique generated spatiotemporal structures of various degrees of order in the maps, which resemble classical wave interference patterns. The patterns thus demonstrate that cell movement is not random and that cells are intrinsically vibrating bodies, transited by self-organized, superpositioned, harmonic modes of rotating oscillatory waves (ROWS). These waves appear to depend upon spatiotemporal oscillations in the physicochemical reactions associated with actin polymerization, and they govern pseudopodial movements, cell shape and locomotion generally. ROWS in this case are unrelated to the cyclic-AMP-regulated oscillations, which characterize later, aggregative populations of Dictyostelium. However, the exposure of aggregation-stage cells to a pulse of the chemoattractant cyclic-AMP induces a characteristic sequence of changes in the global cellular concentration and spatiotemporal distribution of fibrillar (F-)actin. This reaction begins with what appears to be a phase resetting of ROWS and it may, therefore, underlie the cellular perception of and response to chemotactic signals. We also develop here an analytical mathematical description of ROWS, and use it to simulate cell movements accurately.

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