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OBJECTIVE: To explore the influencing factors of low back pain and the relationship of the influence of bad working posture, weight load and frequency of load and the dose-response relationship among the occupational workers of key industries in China. METHODS: A total of 57 501 employees from 15 key industries in China were selected as research subjects using stratified cluster sampling method. The occurrence of low back pain in the past one year, as well as occupational factors such as job type, labor organization and work posture were investigated by using the Chinese version Musculoskeletal Disorders Questionnaire. RESULTS: The prevalence of low back pain in the occupational population of key industries in China was 16.4%(9 448/57 501). Multivariate Logistic regression analysis showed that the risk of low back pain in females was higher than that in males(P<0.01). Married, obese, occasional and frequent smokers, and a history of lower back disease were associated with increased risk of low back pain(all P<0.05). The risk of low back pain was associated with older age, higher education level, and lower frequency of physical exercise(all P<0.01). The risk of low back pain was higher with longer working time, greater back curvature, and the high frequency of long standing and sitting position work, uncomfortable working posture, repeated operation per minute, and lifting>5 kg weight(all P<0.01). CONCLUSION: The influencing factors of low back pain in the occupational population of key industries in China include bad working posture, high frequency load, weight load and other individual factors. There is a dose-response relationship with low back posture load and frequency of load.
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Objective To construct and identify a lentiviral vector carrying mouse Krüppel-like factor 4 (KLF4) gene, and establish RAW264.7 cell line of peritoneal macrophages that over-expressed KLF4. Methods KLF4 gene was cloned using the measure of polymerase chain reaction (PCR). Then the recombinant transfer vector pLVX-KLF4 (pLVX-KLF4-mCMV-ZsGreen-PGK-Puro) was constructed. The pLVX-KLF4 was confirmed through PCR, restriction enzyme digestion and sequencing. The correct recombinant transfer vector together with its two helper virus vectors (psPAX2 and pMD2.G) were cotransfected into the 293T cells by Lipofectamine? 3000. The supernatant of 293T was harvested to infect RAW264.7 cells. Flow cytometry (FCM) was used to test the viral titer of the expression level of green fluorescent protein. The expression of KLF4 mRNA in RAW264.7 cells was measured by real-time PCR. Results The restriction enzyme digestion, PCR and sequencing confirmed that the transfer lentiviral vector pLVX-KLF4 was constructed successfully. KLF4 mRNA was over-expressed in Lenti-KLF4 transfected RAW264.7 cells than that of wild type RAW264.7 cells (P<0.05). In transfected RAW264.7 cells, KLF4 mRNA was over-expressed (P<0.05). The recombinant lentivirus of KLF4(Lenti-KLF4)titer was 2.05×108 TU/mL measured by FCM.The flow cytometry results showed that the S phase fraction was prolonged and G0/G1 was arrested in the over-expressed KLF4 of RAW264.7 cells. The EdU showed that the up-regulated expression of KLF4 gene stimulated the proliferation of RAW264.7 cells. Conclusion The recombinant lentiviral vector, which can effectively express KLF4 mRNA, has been successfully constructed. The up-regulated KLF4 gene may increase the proliferation of RAW264.7 cells.
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Objective To evaluate the performance of the main indicators in the blood analysis of an occupational health exam ination agency by Sigma verification of performance chart and guide quality improvement.Methods Collected blood testing laboratory internal quality control (IQC) data in October 2016 and 2016 second national external quality assessment (EQA) results of the blood analysis laboratory in the agency.Regarded the accumulated coefficient of variability as the estimation value of imprecision.Used the percentage difference in EQA results as the estimation value of bias (％) of the laboratory.The total allowable error in health industry standard WS/T406-2012 was adopted as the quality specification (％).Sigma verification of performance chart of the main eight projects in the blood analysis were drawn with professional software.Results The sigma value of WBC reached σ≥6 level,as the first-class performance,and the sigma values of HGB in the 4≤σ ＜5 level,test performance was good.The sigma value of Hct,HCV and MCHC all were in the 3≤σ＜4 level,as the critical level,and the sigma values of RBC,platelet and MCH in the 2≤σ＜3 level,as poor performance.Conclusion Sigma verifica tion of performance chart could reflect the level of the laboratory testing performance on different test items of blood count,promote the quality improvement.
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Objective To investigate the effect of different pre-enrichment methods on flow cytometry cell sorting of monocyte.Methods Peripheral blood of 15 volunteers were pre-enriched by three methods:erythrocyte lysis,hydroxyethyl starch sedimentation,density gradient centrifugation using Ficoll.Cell viability was detected by Trypan blue staining.The amount and the proportion of monocytes were analyzed by flow cytometry.Results The cell viability of the samples prepared by the 3 methods was above 95 ％.There was no significant difference between the absolute count and grouping of monocytes in erythrocytes lysis and without pre-enrichment samples.The cell subgroup was not obvious by hydroxyethyl starch sedimentation.The number of monocytes obtained by Ficoll density gradient centrifugation was significantly lower than that without pre-enrichment samples.Conclusion Erythrocyte lysis was a high efficient method for monocytes flow cytometry cell sor ting.