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OBJECTIVE: To analyze chromosome damage and its possible influencing factors in patients with occupational chronic benzene poisoning. METHODS: Fifty patients with occupational chronic benzene poisoning were selected as chronic benzene poisoning group,and 53 workers without occupational exposure to benzene and other toxic substances were chosen as control group by using convenience sampling method. Questionnaire and routine blood test were conducted on all study subjects. Micronucleus rate test was performed by micronucleus blocking cytokinesis assay. RESULTS: Peripheral blood tests of chronic benzene poisoning group showed significantly reduced hemoglobin level,counts of red blood cells,white blood cells,platelets,lymphocytes and neutrophils( P < 0. 01),and higher lymphocyte micronucleus rates compared to control group( !: 6. 26‰ vs 3. 91‰,P < 0. 01). The proportion of increased lymphocyte micronucleus rate in chromic benzene poisoning group was also higher than that in control group( 46. 0% vs 5. 7%,P < 0. 01). The multivariate Poisson analysis results indicated that the time after disengagement from benzene exposure was the influencing factor of micronucleus rate in chronic benzene poisoning group( P < 0. 05),after adjusting the confounding factors of gender,age,smoking status,alcohol drinking status and working age of benzene exposure. CONCLUSION: Occupational chronic benzene poisoning leads to increase of chromosome damage in lymphocytes of patients. The time after disengagement from benzene exposure was positively correlated with chromosome damage.
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Objective To generate the erythroid differentiation associated gene(EDAG) knockout mice and analyze their sensitivity to low dose radiation-induced damage.Methods Zinc finger nuclease technology ( ZFNs ) was used to produce the EDAG knockout mice.The low dose radiation-induced damage was evaluated by peripheral blood cell counts, DNA damage and colony formation of bone marrow cells.Wild-type and EDAG knockout mice were irradiated with 0.31 Gy/min X-ray, one minute per day for seven consecutive days, and the cumulative radiation dose was 2.17 Gy(n=7).The blood cell counts were measured by an automated hemocytometer.DNA damage was detected by immunofluorescence assay with a DNA damage marker p-H2A.x antibody (n=3).The colony formation ability of bone marrow cells was evaluated with a semi-solid culture medium(n=3).Results A model of EDAG knockout mice was established.Compared to wide type mice, white blood cell counts of EDAG knockout mice decreased significantly while the DNA damage marker p-H2A.x expression was increased on the third day after X-ray irradiation.The ability of colony-forming was reduced after 7 days of X-ray irradiation.Conclusion Our present study found that EDAG knockout mice are more sensitive to low dose radiation-induced damage as shown by decreased peripheral blood cells counts, reduced colony-forming ability of bone marrow cells, and increased DNA damage.These results suggest that EDAG knockout mice can serve as a powerful tool for evaluation of the biological effects of low-dose radiation damage.