Beschreibung:
<p>Dose-dependent injury to human blood granulocytes was measured within 2 hr of X irradiation, as changes in net <sup>22</sup> Na influx and phagocytosing O<sub>2</sub> consumption. Among samples from normal donors and patients with chronic myeloproliferative diseases, samples from 10 of 12 patients with chronic granulocytic leukemia exhibited increased sensitivity to injury by radiation. Selected granulocyte constituents which may contribute to inactivation of oxidant and free-radical products of radiation-activated H<sub>2</sub> O were also measured. These included glutathione and ascorbate contents; superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase activities; and capacity to take up and reduce dehydroascorbate. Catalase activity was irregularly higher in radiation-sensitive than in radiation-resistant granulocytes (P = <0.05). Dehydroascorbate uptake and reduction was consistently low in radiation-sensitive cells (P = <0.001). We propose that cell capacity to maintain ascorbate in reduced form against oxidant and free-radical stress is a part of mechanisms which determine resistance to injury by ionizing radiation in human granulocytes.</p>