Objective:To examine the expression and function of thrombonspondin-1 (TSP-1) in oxygen-induced retinopathy in new-born mice, and to investigate its role in retinal neovascularization. Methods:A total of 40 C57BL/6J newborn mice were divided equally into a model group (n=20)andanormalcontrolgroup(n=20).Miceinthemodelgroupwereexposedto75%oxygentoestablish the oxygen-induced retinopathy (OIR) model. On the 7th, 9th, and 11th day after the birth of mice, 5 mice were randomly selected each time from the 2 groups to examine the expression of TSP-1 mRNA with reverse transcription polymerase chain reaction (RT-PCR). After that, 5 mice were selected on the 11th day to observe the retinal neovascularization by fluorescein angiography retinal flatmount. Results:On the 11th day, fluorescein angiography retinal flatmount showed that the retinal blood vessels presented mean network distribution in the normal control group, while in the model group, a lot of dilatated areas in the retinal main vessels surrounded the optic disc. Meanwhile lots of new blood vessels were found surrounding the optic disc with irregular distribution but well distributed peripherial retinal small vessels, which was typical of early stage OIR. There was no signiifcant difference in the retinal TSP-1 mRNA level between the model group and the normal control group in the postnatal 7-day mice (P>0.05). Compared with the normal control group, the expression of TSP-1 mRNA in the model group was signiifcantly lower in postnatal 9-day and 11-day mice (P<0.05, P<0.01) , and the expression of TSP-1 mRNA in postnatal 9-day mice was lower than that in the postnatal 11-day mice(P<0.05).
Conclusion:In the early stage of OIR model (retinal vascular growth and development stage), the expression of TSP-1 mRNA in the retinal tissue is gradually decreased, implying that TSP-1 (as a negative regulatory factor) may be involved in the formation of retinal neovascularization in the early stage.

Objective To investigate the prevalence of nosocomial infection among inpatients in a tertiary hospital， and provide scientific evidence for hospital infection control and targeted surveillance. Methods A cross-sectional survey was conducted to investigate a total of 543 hospitalized patients using the hospital information system. Results The prevalence of hospital-acquired infection （HAI） was 4.24%， and that of community-acquired infection （CAI） was 23.39%. HAI prevalence differed significantly among the departments （ χ ²=148.870， P <0.05）， and was highest in the department of intensive care medicine （72.73%）. Sites of infection were significantly different between HAI and CAI （ χ ²=22.942， P =0.011）； however， the most frequent site of infection was lower respiratory tract in both HAI and CAI. Major pathogens for nosocomial infection were Gram-negative bacteria （56.92%）， mainly Escherichia coli and Klebsiella pneumoniae . Antimicrobial usage was observed in 31.68% of the patients， principally for therapeutic use of antibacterial drugs （80.23%） and a combination of drugs （88.95%）. Examination rate of pathogens following the antimicrobial usage was 72.08%. Conclusion The investigation on the prevalence of nosocomial infection may facilitate fully understanding the nosocomial infection. It warrants strengthening the monitoring in the departments of intensive care medicine and on multi-resistant bacteria， and achieving antimicrobial stewardship， so as to improve the awareness of hospital infection control in medical staff' and effectively reduce the occurrence of nosocomial infection.