Background Mast cells are prominent components of solid tumors and exhibit distinct phenotypes in different tumor microenvironments. However, the nature, regulation, function, and clinical relevance of mast cells in human gastric cancer (GC) are presently unknown. Methods Flow cytometry analyses were performed to examine level and phenotype of mast cells in samples from 114 patients with GC. Multivariate analysis of prognostic factors for overall survival was performed using the Cox proportional hazards model. Kaplan-Meier plots for patient survival were performed using the log-rank test. Mast cells, T cells and tumor cells were isolated or generated, stimulated and/or cultured for in vitro and in vivo function assays. Results Patients with GC showed a significantly higher mast cell infiltration in tumors. Mast cell levels increased with tumor progression and independently predicted reduced overall survival. These tumor-infiltrating mast cells accumulated in tumors by CXCL12-CXCR4 chemotaxis. Intratumoral mast cells expressed higher immunosuppressive molecule programmed death-ligand 1 (PD-L1), and mast cells induced by tumors strongly express PD-L1 proteins in both time-dependent and dose-dependent manners. Significant correlations were found between the levels of PD-L1 + mast cells and pro-inflammatory cytokine TNF-α in GC tumors, and tumor-derived TNF-α activated NF-κB signaling pathway to induce mast cell expression of PD-L1. The tumor-infiltrating and tumor-conditioned mast cells effectively suppressed normal T-cell immunity through PD-L1 in vitro, and tumor-conditioned mast cells contributed to the suppression of T-cell immunity and the growth of human GC tumors in vivo; the effect could be reversed by blocking PD-L1 on these mast cells. Conclusion Thus, our results illuminate novel immunosuppressive and protumorigenic roles of mast cells in GC, and also present a novel mechanism in which PD-L1 expressing mast cells link the proinflammatory response to immune tolerance in the GC tumor milieu. Electronic supplementary material The online version of this article (10.1186/s40425-019-0530-3) contains supplementary material, which is available to authorized users.

The vigilance of the driver is important for railway safety, despite not being included in the safety management system (SMS) for high-speed train safety. In this paper, a novel fatigue detection system for high-speed train safety based on monitoring train driver vigilance using a wireless wearable electroencephalograph (EEG) is presented. This system is designed to detect whether the driver is drowsiness. The proposed system consists of three main parts: (1) a wireless wearable EEG collection; (2) train driver vigilance detection; and (3) early warning device for train driver. In the first part, an 8-channel wireless wearable brain-computer interface (BCI) device acquires the locomotive driver’s brain EEG signal comfortably under high-speed train-driving conditions. The recorded data are transmitted to a personal computer (PC) via Bluetooth. In the second step, a support vector machine (SVM) classification algorithm is implemented to determine the vigilance level using the Fast Fourier transform (FFT) to extract the EEG power spectrum density (PSD). In addition, an early warning device begins to work if fatigue is detected. The simulation and test results demonstrate the feasibility of the proposed fatigue detection system for high-speed train safety.

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Fucoxanthin is rich in seaweed and considered as effective anti-cancer drug because of powerful antioxidant properties. The objective of this study was to investigate the role of fucoxanthin on apoptosis, invasion and migration of glioma cells. Firstly, fucoxanthin showed obvious cytotoxicity against human glioma cancer cell line U87 and U251, however, there was no inhibitory effect on normal neuron. And then, fucoxanthin induced apoptotic cell death showed by the condensation of chromatin material stained with Hoechest 33342, and reduced mitochondrial membrane potential via DIOC6(3) staining, and enhanced apoptosis by annexin V-FITC/SYTOX Green double staining on U87 and U251 cell lines. Transmission electron microscopy and western blotting were used to determine ultrastructure of U87 cell and expression of proteins related to apoptosis. A scratch wound healing assay and the expression of matrix metalloproteinases (MMPs), and a tans-well assay were used to investigate cell migration and invasion, respectively. Additionally, we uncovered upstream signaling Akt/mTOR and p38 pathways induced by incubation U87 and U251 cell lines with fucoxanthin that mediated cell apoptosis, migration and invasion by using PI3K and p38 inhibitors. Moreover, incubation of fucoxanthin obviously reduced the weight and volume of glioma mass of U87 cells in nude mice. Furthermore, we also examined the glioma mass of U87 cells by hematoxylin-eosin staining, TUNEL assay and western blot, and these outcomes in vivo consistently confirmed that above results in vitro. Taken together, these findings suggest that fucoxanthin augments apoptosis, and reduces cell proliferation, migration and invasion, and reveals a potential mechanism of fucoxanthin-mediated Akt/mTOR and p38 susspression in human glioblastoma cell line.

A practical method for the N-detosylation of indoles and related heterocycles with KOH in THF and water in the presence of a phase transfer catalyst is described. Using a nonalcoholic solvent, this method prevents the formation of toxic alkyl p-toluenesulfonate and consequently eliminates the formation of even traces of N-alkyl byproduct. This green method is particularly useful for indoles bearing electron-withdrawing groups and for azaindoles.

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The principle cause of cardiovascular disease (CVD) is atherosclerosis, a chronic inflammatory condition characterized by immunologically complex fatty lesions within the intima of arterial vessel walls. Dendritic cells (DCs) are key regulators of atherosclerotic inflammation, with mature DCs generating pro-inflammatory signals within vascular lesions and tolerogenic DCs eliciting atheroprotective cytokine profiles and regulatory T-cell (Treg) activation. Here, the surface chemistry and morphology of synthetic nanocarriers composed of poly(ethylene glycol)-bpoly(propylene sulfide) copolymers to enhance the targeted modulation of DCs by transporting the anti-inflammatory agent 1,25-dihydroxyvitamin D3-(aVD) and ApoB-100-derived antigenic peptide P210 are engineered. Polymersomes decorated with an optimized surface display and density for a lipid construct of the P-D2 peptide, which binds CD11c on the DC surface, significantly enhance the cytosolic delivery and resulting immunomodulatory capacity of aVD in vitro. Weekly lowdose intravenous administration of DC-targeted, aVD-loaded polymersomes significantly inhibit atherosclerotic lesion development in high-fat-diet-fed ApoE −/− mice. The results validate the key role of DC immunomodulation during aVD-dependent inhibition of atherosclerosis and demonstrate the therapeutic enhancement and dosage lowering capability of cell-targeted nanotherapy in the treatment of CVD.

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