Objective To study the effect of Numb gene overexpression on invasion and migration in human renal cell carcinoma cells and its related mechanism. Methods The Numb-ORF plasmid was transfected into renal cell carcinoma cells 786-O, set the negative control and blank control. The expression of Numb and matrix metalloproteinase-9 (MMP-9) was detected by real-time PCR and western blot. Then abilities of cells invasion and migration were measured respectively by transwell assay and scratch-wound-healing assay. Results Compared to negative control (2.51±0.27) and blank control (2.87±0.21), Numb expression in Numb-ORF group (36.13 ±8.33) was significantly higher (P= 0.00). Meanwhile, MMP-9 level in Numb-ORF group was decreased: Numb-ORF group was 2.36±0.29, negative control was 8.73±0.91, blank control was 8.99±0.78 (P=0.00). In scratch-wound-healing assay,the repair ratio of 12 h was as follow: Numb-ORF group was 0.53 ±0.06, negative control was 0.73 ±0.09, blank control was 0.75 ±0.08 (P= 0.02). In transwell assay, the number of invasion cells in Numb-ORF group was 31.40±5.96, less than negative control (126.93±13.61) and blank control (131.87 ±15.42) (P= 0.00). Conclusion Overexpression of Numb significantly decreases abilities of invasion and migration in 786-O cells, and the suppressive effect may be due to the down-regulation of MMP-9 expression in human renal cell carcinoma.

Objective To compare the reliability and validity of job content questionnaire (JCQ1.0) and effort-reward imbalance (ERI) questionnaire in job stress study for civil aviation staff. Methods One hundred and ten individuals were investigated by JCQ1. 0 and ERI questionnaire for job stress, and their reliability and validity were evaluated. Results In JCQ1. 0, high-strain, active, passive,and low-strain workers accounted for 23.6%, 20. 9%, 24. 5%, and 30. 9%. Job stress was found in 59. 1% in ERI. The internal consistency reliabilities (Cronbach α) of the 3 dimensions in JCQ1.0 ranged from 0. 10 to 0. 51, and the split-half reliability was 0. 50; however, the internal consistency reliabilities ( Cronbach α) of the 3 dimensions in ERI ranged from 0. 35 to 0. 79, and the split-half reliability was 0. 78.Most items of both questionnaires showed good construct validities. In factor analysis, total variance contribution was 64. 62% ( JCQ1. 0 ) and 58.08% ( ERI ), respectively. Conclusion ERI may be a reliable and valid tool of job stress assessment; however, JCQ1.0 seems to need further modification.