AIM: To investigate the feasibility and infection efficiency of MSCs with replication-deficient adenovirus containing delivered gene, and whether enhanced green fluorescence protein (EGFP) gene track the change during rMSCs differentiating neuron-like cells. METHODS: Rat marrow mesenchymal stem cells (rMSCs) were expanded in low density in vitro . Under the control of CMV promoter, pAd-EGFP-Vector was constructed by homologous recombination in E.coil BJ 5183, and the recombinant virus was produced in HEK 293 packaging cell line. rMSCs infected with Ad-EGFP were observed and analyzed with fluorescence microscope. Infection efficiency was assessed by microscopical scoring and flow cytometrics. After withdrawing serum and exposure to ?-mercaptoethanol medium, rMSCs infected with Ad-EGFP was induced to differentiate into neuron-like cells. As a control, the plasmid of pTrack-EGFP also was transfected into rMSCs to evaluate transfection efficiency.RESULTS: The results showed that Adenovirus vector (AdVec) delivered EGFP gene with high efficiency to marrow mesenchymal stem cells. Gene expression analysis showed that 36%?2 % of rMSCs infected with recombinant adenovirus expressed the transgene of EGFP at high levels. However, the transfection of plasmid pTrack-EGFP using routine method of lipofectamin mixed with plasmid DNA (pTrack-EGFP) was not easily successful and the transfection efficiency was much lower. rMSCs infected with Ad-EGFP in different passage could differentiate into typical morphology alike neural cells after withdrawing serum and exposure to ?-mercaptoethanol medium. Immuno-staining with neuron-specific enolase (NSE), a neuronal marker, was strong positive, which suggested that rMSCs infected with Ad-EGFP had the potential to differentiate into neurons or neuron-like cells. CONCLUSION: The AdVec system can deliver target gene into MSCs and EGFP gene carried by AdVec can track the change during rMSCs differentiating into neuron-like cells.

AIM: To construct recombinant adenovirus vector containing brain derived neurotrophic factor, (BDNF) gene using bacterial homogenous recombination, and investigate the expression in expanded rat mesenchymal stem cells (rMSC) in vitro. METHODS: BDNF gene and proBDNF gene were subcloned into adenovirus shuttle plasmid pAdTrack-CMV containing enhanced green fluorescent protein gene (EGFP) expression cassette, forming shuttle vector of pAdTrack-BDNF, and pAdTrack-proBDNF, and co-transformed into BJ5183 bacterial cells with adenovirus backbone vector pAdEasy-1 using chemical transformation. After the recombinant adenovirus vector was obtained, the identified recombinant adenovirus plasmid DNA was digested with Pac I and transfected to 293 cells to package recombinant adenovirus particles. rMSC were infected by recombinant adenovirus and EGFP expression was detected using fluorescent microscope. Infection efficiency was assessed by flow cytometrics. Western blotting identified expression of Ad -proBDNF and Ad-BDNF in rMSC. rMSC infected with Ad -proBDNF and Ad-BDNF were induced to differentiate into neuron-like cells. rMSC infected with Ad -proBDNF and Ad-BDNF were injected into nude mice and assessd in vivo. RESULTS: We successfully constructed the recombinant adenovirus Ad -proBDNF and Ad-BDNF that expressed in expanded rMSC in vitro.CONCLUSION: Recombinant adenovirus high-effectively mediates Ad -proBDNF and Ad-BDNF expression in expanded rMSC in vitro and in vivo.

Objective To explore the status, characteristics and factors in relation to occupational stress for medical staffs in tertiary general hospitals. Methods A total of 2460 medical staff were sampled in five tertiary general hospitals in Beijing, with their occupational stress levels evaluated with the Occupational Stress Inventory. Results The top ten stressors as found ranked as heavy duty, high risk exposure, high workload, low wages, setbacks in the health care management system, insufficient staffing, excessively frequent inspections and examinations, strained doctor-patient relationship, price inflation, frequent overtime, and pressure from continuous learning. Occupational stress is seen as moderate and above by 95.2% of the surveyed. Differences in age, gender, marital status, professional title, education, work experience, as well as those of different organizations, departments, professions, and duty were found to be statistically significant in regard of professional stress. Conclusions Stress management should be in place targeting demographic and stress characteristics. Effective measures are recommended to alleviate the pressure on medical staff, in order to maintain their physical and mental health, hence improving their work efficiency and organizational cohesion.

Objective To compare the clinical outcomes and retinal volume changes in patients with ischemic and non-ischemic macular edema secondary to branch retinal vein occlusion(BRVO-ME)using optical coherence tomography angiography(OCTA).Methods The clinical data of 34 ischemic BRVO-ME patients(34 eyes,ischemic group)and 21 non-ischemic BRVO-ME patients(21 eyes,non-ischemic group)were retrospectively analyzed.Patients in both groups re-ceived intravitreal injections of ranibizumab.The best corrected visual acuity(BCVA)and retinal volume of the macular ar-ea were assessed before,1 day,1 week,1 month,3 months and 6 months after the treatment.Results The BCVA(log-MAR)at 1 day after the treatment was 0.63±0.37 in the ischemic group and 0.44±0.22 in the non-ischemic group,and the difference was statistically significant(P=0.017).The retinal volumes of the outer retina,the full retina,and the Farafovea and Perifovea subdivisions of the full retina before the treatment were(6.42±1.90)mm3,(8.75±1.82)mm3,(3.20±0.87)mm3 and(5.10±0.89)mm3 in the ischemic group and(5.52±1.57)mm3,(7.83±1.56)mm3,(2.80± 0.71)mm3,and(4.66±0.77)mm3 in the non-ischemic group,respectively;1 day after treatment,they were(4.97± 1.18)mm3,(7.46±1.47)mm3,(2.62±0.60)mm3 and(4.53±0.80)mm3 in the ischemic group and(4.25±0.48)mm3,(6.58±0.56)mm3,(2.26±0.26)mm3 and(4.06±0.40)mm3 in the non-ischemic group,respectively;at 1 week after the treatment,they were(4.40±0.82)mm3,(6.90±0.85)mm3,(2.38±0.36)mm3 and(4.24±0.49)mm3 in the ischemic group and(4.04±0.35)mm3,(6.33±0.49)mm3,(2.15±0.19)mm3 and(3.95±0.35)mm3 in the non-ische-mic group,respectively,and the differences between the two groups were statistically significant(all P＜0.05).The a-mount of retinal volume change from baseline in the outer retina and the full retina was(-2.48±2.38)mm3 and(-2.54±2.38)mm3 in the ischemic group,and(-1.31±1.58)mm3 and(-1.38±1.58)mm3 in the non-ischemic group at 1 month after treatment,respectively,and the differences between the two groups were statistically significant(both P＜0.05).Conclusion Ranibizumab is effective in treating both ischemic and non-ischemic BRVO-ME.The short-term visu-al prognosis is better in the non-ischemic group than the ischemic group,and the retinal volume is higher in the ischemic group than the non-ischemic group.However,no significant difference is observed in the visual prognosis or retinal volume between the two groups after long-term treatment.