Background Influence of weightlessness on visual function has been a hot topic in aerospace medicine field.Electroretinography (ERG) is valuable tool of evaluating visual function.Objective This study aims to observe the influence of head down tilt simulated weightlessness on ERG.MethodHead down tilt for 6° was adopted in 6 healthy volunteers.Flash ERG,including rod response,maxium response,cone response,oscillatory potentials (OPs) and 30 Hz flicker was recorded,and the latency and amplitude from each wave were analyzed before,two days and five days after trial.The record procedure followed the ISCEV standard for full field clinical electroretinography (2008 update).Oral informed consent was obtained from all the subjects prior to the trail.Results No significant differences were detected in the latencies and amplitudes of a,b waves of cone response and 30 Hz flicker among various time points(P＞0.05).The latencies were significantly prolonged in b wave of rod and a,b waves of maxim responses(P＜0.01),but no obvious change was found in amplitudes (P＞0.05).Both the latency and amplitude of all of the wavelets of OPs were considerably among the different time points(P＜0.05-0.01),and the ∑OPs was evidently different among the different time points(P＜0.05).Conclusion Head down tilt simulated weightlessness induce the abnormality of visual function in the early stage.

Objective To observe the influence of head-down tilt on visual evoked potential.Methods Six healthy volunteers were exposed to-6? head-down tilt.The visual evoked potential were measured before the test,the second day and the fifth day of the test under different space frequency.Results No significant difference was found in the latency of P100 before and after the test.The amplitude of P100 had significant change under high space frequency.But not the same happened on middle and low space frequency.Conclusion head-down tilt can induce the change of visual evoked potential under high space frequency,which means the weightlessness may influent the visual function.

BACKGROUND: Silk fibroin film showed an anti-coagulated blood activity following sulfurous acid treatment; however, its flexibility and anti-tension were poor. If the silk flbroin film was coated on small-caliber expanded poly(tetrafiuoroethylene) (ePTFE) vascular grafts prior to surface sulfonation, the adverse effects were improved and the blood compatibility of ePTFE vascular grafts were remarkably enhanced. OBJECTIVE: To research the preparation of ePTFE vascular grafts applied by surface sulfonation of silk flbroin film by low temperature plasma treatment. METHODS: The ePTFE vascular grafts were treated with low temperature plasma and coated on the surface of silk fibroin. The compound was then sulfonated with low temperature plasma. The ePTFE vascular grafts were considered as the controls to detect contact angle and sulfonation. RESULTS AND CONCLUSION: The contact angle was decreased gradually form 87.7°to 65.1° following low temperature plasma treatment. Moreover, the contact angle was 106.2° following coating silk flbroin film and 92.9°following sulfonation. X-raylight-electron spectrometer demonstrated that percents of sulfur element on the surfaces of the combined blood vessel was 2.89%, respectively, while that of the control film was only 0.12%. The X-ray light-electron spectrometer also showed that most of the sulfur element were sulfonic group (-SO_3H). The results suggested the feasibility of the preparation of the combined blood vessel.

Objective To evaluate the influences of susceptibility interpretation of Escherichia coli,Klebsiella pneumonia and Proteus mirabilis in China mainland according to the old and new ceftazidime,cefotaxime and ceftriaxone breakpoints in CLSI M100-S20 and CLSI M100-S19. Methods First, We analyzed the antibacterial susceptibility results of the three bacteria by agar dilution method in the SEANIR surveillance item, which were collected from 15 national hospitals between the year of 2005 and 2007 and excluded the AmpC enzyme positive isolates according to the PGR-DNA sequencing method and/or the antibacterial susceptibility phenotype. ESBL phenotype was confirmed by the CLSI phenotypic confirmatory test. Antibacterial susceptibility of the total 2733 Escherichia coli, Klebsiella pneumonia, Proteus mirabilis isolates was retrospectively analyzed by WHONET 5. 4 software according to the breakpoints of the CLSI M100-S19 (S19) and CLSI M100-S20 (S20). Second, 207 isolates of Peking Union Medical College Hospital with the results of both agar dilution method and disk diffusion method were performed by recurrent analysis. Then we observed the inter-method agreement through the scatter diagram according to the breakpoints of S19 and S20. Results First, as to the ESBL positive Escherichia coli, Klebsiella pneumonia and Proteus mirabili.s, the resistant rate of cefotaxime increased from 65.2% , 55.5%, 14. 6% under S19 (64 μg/ml) to 99. 7%, 96. 2% , 93. 8% under S20 (4 μg/ml). The susceptibility rates decreased from 6. 0%, 11.5%, 33.3% under S19 (8 μg/ml) to 0%, 0. 2%, 0% under S20 ( 1 μg/ml). Ceftriaxone had the same trend as cefotaxime. Though ceftazidime was more active than cefotaxime and ceftriaxone, as to the ESBL positive Escherichia coli and Klebsiella pneumonia, the resistant rates slightly increased from 30. 3%,43. 2% under S19 (32 μg/ml) to42.0%, 56. 0% under S20 (16 μg/ml). The susceptibility rates slightly decreased from 58. 1%, 44. 1% under S19 (8 μg/ml) to 44. 7%, 28.0% under S20 (4 μg/ml). Second,as to the ESBL negative Escherichia coli, Klebsiella pneumonia and Proteus mirabilis, all the susceptibility rates of ceftazidime, cefotaxime and ceftriaxone were between 99. 2%-100. 0%, the resistant rate were between 0%-0. 4%. Third, the S20 MIC breakpoints had a good correspondence with the ESBL phenotype.Fourth, according to the recurrent analysis of MIC testing and disk dilution method, r value was 0. 67,0. 79, 0. 77 for ceftazidime, cefotaxime and ceftriaxone, respectively, and all P value were under 0. 01. The intermethod rates of S19 and S20 were both acceptable. Conclusions If the cefotaxime and ceftriaxone S20 new breakpoints were used, the concordance of antibacterial susceptibility results and ESBL phenotype would increase greatly. The clinician could select proper antibiotics according to the antibacterial susceptibility results and clinical symptoms. It is no longer necessary to edit results for cephalosporins, aztreonam, or penicillins from susceptible to resistant. However, until laboratories implement the new interpretive criteria,ESBL testing should be performed as described in Supplemental Table 2A-S1. The relationship between the new breakpoints of ceftazidime and clinical outcomes need to be further evaluated.

Objective To provide the experimental basis for the subsequent genetic diversity research through establishing and optimizing the inter-simple sequence repeat PCR (ISSR-PCR) reaction system of Gnaphalium affine. Methods The single-factor experimental method and full experimental method were used to optimize the ISSR-PCR reaction system of Gnaphalium affine. Under the optimal system, after screening primers and corresponding annealing temperatures, the systematic feasibility was verified. Results The optimal ISSR-PCR reaction system was consisted of 10 μl Premix Taq DNA polymerase, 0.3 μmol/L primer, 10 ng DNA template, and sterilized water added to 20 μl. Finally, 10 primers were screened from 100 universal primers, and verification results indicated the system had high stability, good reproducibility, and the selected primers had good polymorphism. Conclusion The ISSR-PCR amplification system of Gnaphalium affine was established for the first time and the primers with appropriate annealing temperatures were filtered out, which provided a reference for the subsequent genetic diversity research of Gnaphalium affine.