A microdevice for parallelized pulmonary permeability studies

We describe a compartmentalized microdevice specifically designed to perform permeability studies across a model of lung barrier. Epithelial cell barriers were reproduced by culturing Calu-3 cells at the air-liquid interface (AIC) in 1 mm² microwells made from a perforated glass slide with an embedded porous membrane. We created a single basolateral reservoir for all microwells which eliminated the need to renew the growth medium during the culture growth phase. To perform drug permeability studies on confluent cell layers, the cell culture slide was aligned and joined to a collection platform consisting in 35 μL collection reservoirs connected at the top and bottom with microchannels. The integrity and functionality of the cell barriers were demonstrated by measurement of trans-epithelial electrical resistance (TEER), confocal imaging and permeability assays of ¹⁴C-sucrose. Micro-cell barriers were able to form confluent layers in 1 week, demonstrating a similar bioelectrical evolution as the Transwell systems used as controls. Tight junctions were observed throughout the cell-cell interfaces, and the low permeability coefficients of ¹⁴C-sucrose confirmed their functional presence, creating a primary barrier to the diffusion of solutes. This microdevice could facilitate the monitoring of biomolecule transport and the screening of formulations promoting their passage across the pulmonary barrier, in order to select candidates for pulmonary administration to patients.     

Composite pullulan–dextran polysaccharide scaffold with interfacial polyelectrolyte complexation fibers: A platform with enhanced cell interaction and spatial distribution

Hydrogels are highly preferred in soft tissue engineering because they recapitulate the hydrated extracellular matrix. Naturally derived polysaccharides, like pullulan and dextran, are attractive materials with which to form hydrophilic polymeric networks due to their non-immunogenic and non-antigenic properties. However, their inherent hydrophilicity prevents adherent cell growth. In this study, we modified pullulan–dextran scaffolds with interfacial polyelectrolyte complexation (IPC) fibers to improve their ability to support adherent cell growth. We showed that the pullulan–dextran–IPC fiber composite scaffold laden with extracellular matrix protein has improved cell adhesion and proliferation compared to the plain polysaccharide scaffold. We also demonstrated the zero-order release kinetics of the biologics bovine serum albumin and vascular endothelial growth factor (VEGF) incorporated in the composite scaffold. Lastly, we showed that the VEGF released from the composite scaffold retained its capacity to stimulate endothelial cell growth. The incorporation of IPC fibers in the pullulan–dextran hydrogel scaffold improved its functionality and biological activity, thus enhancing its potential in tissue engineering applications.     

Definition of pulmonary embolism‐related death and classification of the cause of death in venous thromboembolism studies: Communication from the SSC of the ISTH

Pulmonary embolism (PE)‐related death is often a component of the primary outcome in venous thromboembolism (VTE) clinical studies. Definitions for PE‐related death vary widely, which may lead to biased risk estimates of clinical outcomes, thereby affecting both internal and external validity of study results. We here provide a standardized definition of PE‐related death and propose guidance for classification and reporting of the cause of death for clinical studies in VTE. The proposal was developed in a four‐step process, including a systematic review of definitions used for PE‐related death in previous studies, two subsequent surveys with VTE experts, and meetings held within the Scientific and Standardization Committee (SSC) working group until consensus on the proposal was reached. The proposed classification comprises three categories: Category A: PE‐related death, category B: undetermined cause of death, and category C: cause of death other than PE. Category A includes A1: autopsy‐confirmed PE in the absence of another more likely cause of death; A2: objectively confirmed PE before death in the absence of another more likely cause of death; and A3: PE is not objectively confirmed, but is most likely the main cause of death. Category B includes B1: cause of death is undetermined, despite available information; and B2: insufficient clinical information available to determine the cause of death. The use of the proposed definition will hopefully improve the accuracy of study outcomes, between‐study comparisons, meta‐analyses, and validity of future clinical VTE studies.     

河北省儿童医院住院患儿EB病毒感染流行病学特征

目的了解河北省儿童医院住院患儿EB病毒(EBV)感染的流行病学特征,为儿童EBV感染的诊断和预防提供科学依据。方法收集2017年1—12月河北省儿童医院0~14岁EBV感染住院患儿的全血样本,采用酶联免疫吸附试验(ELISA)检测其EBV衣壳抗原(VCA)IgG及IgM抗体,抗早期抗原(EA)IgG抗体和抗核抗原1(NA1)IgG抗体,以检测结果为研究样本的抗体谱。根据4种EBV抗体的检测结果分为现症感染(抗VCA-IgM抗体阳性,抗NA1-IgG抗体阴性、抗VCA-IgG抗体、抗EA-IgG抗体阳性或阴性)、亚急性感染(抗VCA-IgG抗体阳性,抗VCA-IgM抗体、抗NA1-IgG抗体、抗EA-IgG抗体阳性或阴性)、既往感染(抗NA1-IgG抗体阳性,抗VCA-IgG抗体阳性或阴性,其他抗体均为阴性)和未感染(4种抗体均阴性)。按照患儿年龄、检出月份和性别分析各组的阳性率。结果共纳入符合要求的样本4 451例,其中3 257例(73.17%)抗体谱提示EBV感染,包括现症感染380例(8.54%)、亚急性感染616例(13.84%)、既往感染2 261例(50.80%)。不同年龄组原发阳性检出率差异有统计学意义(P<0.05),其中学龄前(>3岁)组的阳性检出率最高(P<0.05);不同检出月份组阳性检出率差异有统计学意义(P<0.05),7月份阳性检出率高于其他月份(P<0.05);男性患儿与女性患儿EBV感染率差异无统计学意义(P>0.05)。380例现症感染患儿的疾病谱以血液系统疾病[传染性单核细胞增多症、急性粒细胞缺乏症、血小板减少性紫癜、EBV相关嗜血细胞综合征]为主,其中传染性单核细胞增多症为临床常见疾病;其次是呼吸系统疾病(急性支气管炎、疱疹性咽峡炎、急性扁桃体炎);其他疾病谱包括神经系统疾病及血流感染、肾病综合征、川崎病。结论河北省儿童医院住院患儿EBV阳性检出率有年龄和检出月份差异,现症感染以血液系统疾病患儿为主,医院应根据流学病学特征制定相应预防措施。     

Synthesis of new piperazinyl-pyrrolo[1,2-a]quinoxaline derivatives as inhibitors of Candida albicans multidrug transporters by a Buchwald–Hartwig cross-coupling reaction

Two series of piperazinyl-pyrrolo[1,2-a]quinoxaline derivatives were prepared via a Buchwald–Hartwig cross-coupling reaction and then evaluated for their ability to inhibit the drug efflux activity of CaCdr1p and CaMdr1p transporters of Candida albicans overexpressed in a Saccharomyces cerevisiae strain. In the initial screening of twenty-nine piperazinyl-pyrrolo[1,2-a]quinoxaline derivatives, twenty-three compounds behaved as dual inhibitors of CaCdr1p and CaMdr1p. Only four compounds showed exclusive inhibition of CaCdr1p or CaMdr1p. Further biological investigations were developed and for example, their antifungal potential was evaluated by measuring the growth of control yeast cells (AD1-8u⁻) and efflux pump-overexpressing cells (AD-CDR1 and AD-MDR1) after exposition to variable concentrations of the tested compounds. The MIC₈₀ values of nineteen compounds ranging from 100 to 901 μM for AD-CDR1 demonstrated that relative resistance index (RI) values were between 8 and 274. In comparison, only seven compounds had RI values superior to 4 in cells overexpressing Mdr1p. These results indicated substrate behavior for nineteen compounds for CaCdr1p and seven compounds for CaMdr1p, as these compounds were transported via MDR transporter overexpressing cells and not by the AD1-8u⁻ cells. Finally, in a combination assay with fluconazole, two compounds (1d and 1f) have shown a synergistic effect (fractional inhibitory concentration index (FICI) values ≤ 0.5) at micromolar concentrations in the AD-MDR1 yeast strain overexpressing CaMdr1p-protein, indicating an excellent potency toward chemosensitization.

Two series of piperazinyl-pyrrolo[1,2-a]quinoxaline derivatives were prepared via a Buchwald–Hartwig cross-coupling reaction and then evaluated for their ability to inhibit the drug efflux activity of two Candida albicans transporters.