乌司他丁对炎症状态下血管内皮屏障功能的影响及机制

目的阐明乌司他丁（UTI）对炎症状态下血管内皮屏障功能的影响及具体分子机制。 方法以人脐静脉内皮细胞系EA.hy926为研究对象,建立炎症细胞模型及RhoA过表达细胞模型,分别用UTI和TNF-α处理细胞,采用Transwell法、TEER法检测细胞通透性;Western Blot法及RT-PCR法检测Rho/ROCK信号通路相关关键分子（RhoA、ROCK2、MYPT1、p-MYPT1及VE-cadherin）的表达变化情况。 结果与正常对照组相比,TNF-α作用后EA.hy926细胞电阻值明显降低,细胞通透性显著升高,差异具有统计学意义[（33.67±4.04）Ω/cm² vs（67.17±3.81）Ω/cm²,t=10.435,P<0.01],细胞内RhoA、ROCK2、p-MYPT1的表达量明显增加,差异具有统计学意义（均P<0.05）,VE-cadherin的表达量明显降低,差异具有统计学意义（P<0.05）,而UTI可逆转上述变化情况;与UTI处理组相比,RhoA过表达细胞模型中RhoA、ROCK2及p-MYPT1的表达显著增高,VE-cadherin表达降低,细胞通透性增加,差异具有统计学意义（均P<0.05）,而空载病毒组中上述分子的表达水平以及细胞通透性无明显变化,差异无统计学意义（均P>0.05）。 结论UTI能通过Rho/ROCK信号通路抑制TNF-α引起的血管内皮细胞通透性增加,改善血管内皮屏障功能障碍。     

Immunisation of common marmosets with vaccinia virus expressing Epstein-Barr virus (EBV) gp340 and challenge with EBV

Epstein-Barr virus (EBV) is the cause of infectious mononucleosis and is associated with a variety of life-threatening diseases in humans. Therefore the development of an effective vaccine is an important objective. Many of the initial studies of vaccine efficacy analyse the ability of vaccine preparations to prevent the induction of lymphomas in cottontop tamarins by the B95-8 strain of EBV. We used a vaccinia virus recombinant expressing gp340, vMA1, tested previously in the cotton-top tamarin, to evaluate a common marmoset model in which the challenge virus, M81, resembles more closely the wild-type strains of EBV in the general population than does the standard B95-8 strain. We characterised the M81 strain of EBV with respect to the sequence of its gp340/220 gene and in regard to the presence of a region deleted in B95-8. Replication of the challenge virus in the group vaccinated with vMA1 was decreased when compared to control groups. © 1996 Wiley-Liss, Inc.     

Hematotoxocity among Chinese workers heavily exposed to benzene

Benzene is a well-established hematotoxin. However, reports of its effects on specific blood cells have been somewhat inconsistent and the relative toxicity of benzene metabolites on peripheral blood cells in humans has not been evaluated. We compared hematologic outcomes in a cross-sectional study of 44 workers heavily exposed to benzene (median: 31 parts permillion [ppm] as an 8-hr time-weighted average [TWA] and 44 age and gender-matched unexposed controls from Shanghai, China. All hematologic parameters (total white blood cells [WBC], absolute lymphocyte count, platelets, red blood cells, and hematocrit) were decreased among exposed workers compared to controls, with the exception of the red blood cell mean corpuscular volume (MCV), which has higher among exposed subjects. In a subgroup of workers who were not exposed to more than 31 ppm benzene on any of 5 sampling days (n = 11, median 8 hr TWA = 7.6 ppm, range = 1–20 ppm), only the absolute lymphocyte count was significantly different between exposed workers (mean [sd] 1.6 [0.4] x 10³ μL) and controls (1.9 [0.4] x 10³ μL, p = 0.03). Among exposed subjects, a dose-response relationship with various measures of current benzene exposure (i.e., personal air monitoring, benzene metabolites in urine) was present only for the total WBC count, the absolute lymphocyte count, and the MCV. Correlations between benzene metabolites and hematologic parameters were generally similar, although hydroquinone was somewhat more strongly associated with a decrease in the absolute lymphocyte count, and catechol was more strongly associated with an increase in MCV. Morphologic review of peripheral blood slides demonstrated an excess of red blood cell abnormalities (i.e., stomatocytes and target cells) only in the most heavily exposed workers, with no differences in granulocyte, lymphocyte, or platelet morphology noted. Although benzene can affect all the major peripheral blood elements, our results support the use of the absolute lymphocyte count as the most sensitive indicator of benzene-induced hematotoxicity. © 1995 Wiley-Liss, Inc.     

Epidemiology,etiology, and outcomes of in-hospital cardiac arrest in Lebanon

BACKGROUNDIn-hospital cardiac arrest (IHCA) constitutes a significant cause of morbidity and mortality. As data is scarce in the Middle East and Lebanon, we devised this study to shed some light on it to better inform both hospitals and policymakers about the magnitude and quality of IHCA care in Lebanon.METHODSWe analyzed retrospective data from 680 IHCA events at the American University of Beirut Medical Center between July 1, 2016 and May 2, 2019. Sociodemographic variables included age and sex, in addition to the comorbidities listed in the Charlson comorbidity index. IHCA event variables were day, event location, time from activation to arrival, initial cardiac rhythm, and the total number of IHCA events. We also looked at the months and years. We considered the return of spontaneous circulation (ROSC) and survival to discharge (StD) to be our outcomes of interest.RESULTSThe incidence of IHCA was 6.58 per 1,000 hospital admissions (95% CI: 6.09−7.08). Non-shockable rhythms were 90.7% of IHCAs. Most IHCA cases occurred in the closed units (87.9%) (intensive care unit, respiratory care unit, neurology care unit, and cardiology care unit) and on weekdays (76.5%). ROSC followed more than half the IHCA events (56%). However, only 5.4% of IHCA events achieved StD. Both ROSC and StD were higher in cases with a shockable rhythm. Survival outcomes were not significantly different between day, evening, and nightshifts. ROSC was not significantly different between weekdays and weekends; however, StD was higher in events that happened during weekdays than weekends (6.7%vs. 1.9%, P = 0.002). CONCLUSIONSThe incidence of IHCA was high, and its outcomes were lower compared to other developed countries. Survival outcomes were better for patients who had a shockable rhythm and were similar between the time of day and days of the week. These findings may help inform hospitals and policymakers about the magnitude and quality of IHCA care in Lebanon.

In-hospital cardiac arrest (IHCA) constitutes a significant cause of morbidity and mortality.^[1] Based on the American Heart Association’s Get With The Guidelines-Resuscitation (GWTG-R) registry data from 2003 to 2007, the approximated incidence of IHCAs in the United States was 211,000 annually or roughly 6 to 7 cardiac arrests per 1,000 hospital admissions.^[2,3] Data from 2008 to 2017 showed the incidence of IHCA increased to 292,000 annually or 9 to 10 IHCAs per 1,000 hospital admissions.^[1,4] In contrast, data from the United Kingdom National Cardiac Arrest Audit showed an incidence of 1.6 IHCAs per 1,000 hospital admissions in the United Kingdom from 2011 to 2013.^[1] Despite progress in resuscitation technology and care, survival outcomes following IHCA remain low at 15%−25% and vary radically between 0% and 42% worldwide.^[5,6] Sandroni, et al.^[5] showed that various patient and healthcare-related factors are associated with the survival outcomes of IHCA. The main patient-related factors are age, sex, initial cardiac rhythm, underlying medical condition, comorbidities, and the time of the IHCA event. In contrast, major healthcare-related factors are the protocols for IHCA care, duration and method of resuscitation, skills of healthcare professionals, time from code activation and the arrival of the code response team, and the location of the IHCA event.^[5,7] The study by Chen, et al.^[8] suggests that improving the quality of resuscitation care and minimizing other healthcare-related risk factors can markedly increase survival outcomes from IHCAs.^[6,9]Consistent and updated estimates of the magnitude and outcomes of IHCA are fundamental for monitoring and improving the delivery and quality of IHCA care in any healthcare setting. In Lebanon, studies have shown low survival rates (5.5%) from out-of-hospital cardiac arrest.^[10]The reported incidence of IHCA in the United Arab Emirates was 11.7 per 1,000 hospital admissions,^[6] and in Saudi Arabia was 7.76 per 1,000 hospital admissions.^[11] The reported survival to hospital discharge in the United States was only 10.4%,^[12] and it was only 7.9% in the United Kingdom.^[13] However, unlike European countries and the United States, the epidemiology of IHCA is unknown in Lebanon, suggesting the need for research in this area. Therefore, this study aimed to produce the first estimates of the incidence, characteristics, and outcomes of IHCA at a tertiary-care hospital in Lebanon.     

Metasurfaces for Far-Field Radiation Pattern Correction of Antennas under Dielectric Seamed-Radomes

A high-index dielectric radome seam is camouflaged with respect to a low-index dielectric radome panel by tuning the seam with carefully engineered metasurfaces. A transmission-line approach is used to model the metasurface-tuned seam and analytically retrieve the corresponding surface impedance, from which the unit-cell design is then tailored. Full-wave simulations and microwave antenna measurements performed on a proof-of-concept prototype validate the undesired scattering suppression effect in the case of normally and obliquely incident transverse electric and transverse magnetic wave illuminations. Robustness of the proposed solution to fabrication tolerances is also reported. The study presents metasurface-tuning as an easily implementable, frequency adjustable, and polarization insensitive solution to reduce the scattering of dielectric mechanical seams and improve the overall transparency performance of radome structures.