Dynamics of Leucocytes and Leucogram after a Single Human Exposure to Doses below 1 Gy
Purpose: To assess the functional status of granulocyte-macrophage stem according to peripheral blood counts in the coming 60 days after a single gamma-beta radiation in doses less than 1 Gy. Material and methods: A group of 67 humans exposed to a low - radiation dose (0.1-0.9 Gy) due to the Chernobyl power plant catastrophe (31 people) and nuclear arms tests at Novaya Zemlya (36 people) were tested for blood composition and thrombocyte count. The counts of red blood and thrombocytes were studied within a period of 58-60 days since the exposure. The values obtained were compared against daily blood counts of 21 volunteers (15 males and 6 females) in the course of 60 days period. The statistical data were analyzed applying Statistica 6.0 software. Results: With a single external gamma-beta exposure to doses less than 1 Gy, all changes in the leucocytes rate and leucogram structure do not go beyond the physiological norm. Those subjected to irradiation at Novaya Zemlya in doses of 0.1-0.2 Gy showed an increase in the mean values of these parameters to the upper limit of normal at days 7 to 20. At relatively higher doses of radiation of 0.4-0.6 Gy (0.5 Gy), this phenomenon was not observed and the mean rate of leucocytes (neutrophils) was close to the lower boundary of the norm within 58 days of observation. In persons exposed to radiation at Chernobyl, the leucocyte and neutrophil curves at doses of radiation exposure of 0.1-0.9 Gy have also demonstrated a slight short-term increase (14 to 16 days) of these values, with the subsequent decrease since days 17 to 23. At doses of 0.6-0.9 Gy, neutrophil count was reduced to the lower limit of normal. Conclusion: At doses of radiation exposure of 0.1-0.9 Gy, the leucocyte and neutrophil curves have indicated to a number of features: abortive rise of the mean level of neutrophils with a subsequent decline in their counts at weeks 3-4 and a further reduction to the average level. In days 35 to 50, a secondary retraction of the level of peripheral blood neutrophils was revealed. Neutrophils curve in persons with «0» dose corresponded to those irradiated from 0.1 to 0.9 Gy. At doses ofradiation exposure exceeding 0.4 Gy, the decrease in the mean count of neutrophils goes down to the lower limit of normal one.