Objective: To investigate the effects on human peripheral blood erythrocytes of long-term occupational contact with chromate. Methods: A dynamic cohort study was conducted of chromate-exposed workers (343 cases) and non-chromate-exposed workers (73 cases) at a chromate production enterprise who were selected according to specific inclusion and exclusion criteria from 2010 to 2015. Personal information and chromate exposure information were obtained by questionnaire. A generalized estimating equation was employed to analyze the effects on human peripheral blood erythrocytes of long-term occupational contact with chromate, controlling for age, gender, smoking, alcohol consumption and body mass index. Results: The mean ages and working ages of those entering the cohort study were 36.67 ±6.78 and 38.47 ± 7.18, respectively, for the exposure group and 8.39 ± 6.02 and 12.86 ± 8.34, respectively, for the control group. The erythrocyte content [(4.73±0.46), (4.81±0.53), (4.41±0.45)]×10¹²/L in the peripheral blood in the chromate exposure group was lower than that [(4.76±0.42), (4.95±0.45), (4.47±0.39)]×10¹²/L in the control group for the years 2010, 2011, 2012 and 2014 (t values were 0.38, 1.96, 0.92 and 1.21; P values were 0.703, 0.051, 0.358 and 0.227, respectively). The correlations between the years 2010 and 2011, 2011 and 2012, 2012 and 2014, and 2014 and 2015 were 0.667, 0.464,-0.070 and 0.020, respectively (P<0.001). The RR for males and those that consumed alcohol were 0.661 (95% CI: 0.616-0.709) and 0.910 (95% CI: 0.811- 1.201), respectively. Compared with the control group, the risk of reduced erythrocyte levels in the peripheral blood was increased by 0.915 (95% CI: 0.852- 0.982) in the chromate-exposed group. Conclusions The erythrocyte content of peripheral blood was reduced after long-term exposure to chromate. Maleness and alcohol consumption were factors that increased the risk of reduced peripheral blood erythrocytes in the chromate-exposed population.

BACKGROUND:Bone transport has been used for a variety of reasons in bone defects with good clinical results.However,various complications have also attracted the attention of practitioners and the avoidance of non-healing of the docking point has become a common concern for doctors and patients. OBJECTIVE:To explore effective methods of avoiding non-healing of the docking point in the treatment of tibial bone defects by bone transport so as to shorten the treatment period and reduce the pain of patients. METHODS:The clinical data of 21 patients with unilateral tibial bone defect admitted to the No.910 Hospital of Joint Logistics Support Force of Chinese PLA from January 2018 to January 2021 were retrospectively analyzed,including 16 males and 5 females,aged(32.8±10.3)years,with an average bone defect length of 10.2 cm.All 21 patients received bone transport surgery,during which the bone defect area was filled with bone cement to reduce the adverse factors affecting the healing of the docking point.The Association for the Study and Application of the Methods of Ilizarov,healing index and incidence of adverse reactions were evaluated during postoperative follow-up. RESULTS AND CONCLUSION:The 21 patients were followed up for 15 to 24 months after surgery,and the extended area was all well mineralized and had no malformations,and no refractures occurred during treatment.Among them,one patient had foot drop,which could not be completely corrected after surgical release of the Achilles tendon and wearing foot and ankle orthotics.19 patients had different degrees of needle tract infection,and no deep infection occurred after timely needle tract nursing.The healing rate of the docking point was 100%;the healing index was 36-45 d/cm and the average was 38 d/cm.The Association for the Study and Application of the Methods of Ilizarov showed that bone healing was excellent in 17 cases(81%)and poor in 4 cases(19%).The results of limb function were excellent in 18 cases(86%)and good in 3 cases(14%).These findings show that bone cement segmental filling during bone transport is an effective method to solve the non-healing of the docking point,shorten the patient's treatment period and reduce the patient's pain.

Objective:To investigate chromosomal aberrations in peripheral blood lymphocytes of underground miners, in order to explore the influencing factors involved in chromosomal aberration levels of non-uranium metal mines.Methods:Totall 135 workers were recruited from an iron mine and a gold mine located in different cities of Henan province, where 69 workers worked aboveground and 66 miners worked underground in the metal mines. The radon concentration in the mines was measured by solid-state nuclear track detectors. Chromosomal aberrations in peripheral blood lymphocytes from the subjects were detected using conventional analysis method, and the influence factors of chromosomal aberrations were analyzed.Results:Radon concentration was 30-2 943 Bq/m 3 in the aboveground workplace of the mines, and 62-28 314 Bq/m 3 in underground. The age of the underground group was obviously lower than that of the aboveground group( t=2.12, P<0.05), but the frequencies of dicentrics, translocation, acentric fragment, and total chromosome-type aberrations in the underground group were significantly higher than those in the aboveground group ( χ2=10.49, 16.74, 8.15, 29.50, P<0.01). Consistent results were obtained when only male workers were regarded as object of observation ( χ2=8.44, 11.63, 4.94, 20.81, P<0.05). The frequency of translocation ( χ2=8.44, P<0.05) was dependent on the length of service in the underground group. Poisson regression analysis indicated that the aboveground and undergroud grouping partly affected the levels of dicentrics, translocation, acentric fragment, and total chromosome-type aberrations (the underground group IRR=3.25, 2.69, 1.97, 2.18, P<0.05). Conclusions:The radon exposure in the underground workplace of the metal mines may be the main factor resulting in the increase of chromosome-type aberrations of miners. The occupational health and safety of the miners who may be exposed to high radon levels are worthy of great attention.