Wei-Ping Xu

Facile synthesis of silver@graphene oxide nanocomposites and their enhanced antibacterial properties

Uniform and water-soluble Ag@reduced graphene oxide (Ag@rGO) nanocomposites can be prepared by a facile approach in the absence of additional reductants, which display much better antibacterial properties than that of pure silver nanoparticles synthesized by microwave irradiation, and an equivalent antibacterial effect in comparison with that of the general antibacterial drug ampicillin. Their skin irritation tests with the use of rat models are taken in order to explore the toxicity of this nanocomposite, which confirm that no oedema or erythema appears on the injured rat skin after exposure to the as-prepared Ag@rGO nanocomposites.

Highly active carbonaceous nanofibers: a versatile scaffold for constructing multifunctional free-standing membranes.

Translating the unique characteristics of individual nanoscale components into macroscopic materials such as membranes or sheets still remains a challenge, as the engineering of these structures often compromises their intrinsic properties. Here, we demonstrate that the highly active carbonaceous nanofibers (CNFs), which are prepared through a template-directed hydrothermal carbonization process, can be used as a versatile nanoscale scaffold for constructing macroscopic multifunctional membranes. In order to demonstrate the broad applicability of the CNF scaffold, we fabricate a variety of CNF-based composite nanofibers, including CNFs-Fe(3)O(4), CNFs-TiO(2), CNFs-Ag, and CNFs-Au through various chemical routes. Importantly, all of them inherit unique dimensionality (high aspect ratio) and mechanical properties (flexibility) of the original CNF scaffolds and thus can be assembled into macroscopic free-standing membranes through a simple casting process. We also demonstrate the wide application potentials of these multifunctional composite membranes in magnetic actuation, antibiofouling filtration, and continuous-flow catalysis.

Prognostic Role of Human Epidermal Growth Factor Receptor in Gastric Cancer: A Systematic Review and Meta-analysis

BACKGROUND AND AIMS Human epidermal growth factor receptor (EGFR) and HER2 (ErbB2) both belong to EGFR family, which are overexpressed in a significant proportion of cases of gastric cancer (GC). Various studies have evaluated the prognostic value of EGFR or HER level in GC. However, the overall test performance remains unclear. We undertook this study to perform a systematic review and meta-analysis of prognostic cohort studies evaluating the use of EGFR or HER2 as a predictor of survival time in patients with GC. METHODS Eligible studies were identified through multiple search strategies. Studies were assessed for quality using the Newcastle-Ottawa Tool. Data were collected comparing overall survival (OS) in patients with high and low EGFR or HER2 level. Studies were pooled and summary hazard ratios were calculated. RESULTS Studies were listed twice if they provided overall survival data for both EGFR and HER2. Eight studies (seven for EGFR and eight for HER2) were included. Two distinct groups were pooled for analysis and revealed that high EGFR, HER2 levels predicted poor overall (HR = 1.66, 95% CI: 1.35-2.02) and (HR = 1.43, 95% CI: 1.09-1.88) survival. No publication bias was found. CONCLUSIONS This meta-analysis result suggested that EGFR or HER2 should have significant predictive ability for estimating overall survival in GC patients and may be useful for defining prognosis of GC patients.

Microbiota modulate tumoral immune surveillance in lung through a γδT17 immune cell-dependent mechanism

Commensal bacteria are crucial to maintain immune homeostasis in mucosal tissues and disturbances in their ecology can affect disease susceptibility. Here, we report evidence that commensal bacteria shape the efficiency of immune surveillance in mucosal tissues. Antibiotic-treated (Abt) mice were more susceptible to development of engrafted B16/F10 melanoma and Lewis lung carcinoma, exhibiting a shortened mean survival time with more numerous and larger tumor foci in the lungs. The defective antitumor response of Abt mice was independent of dehydration caused by antibiotics. Host defenses relied upon intact commensal bacteria with no class specificity. Mechanistic investigations revealed a defective induction of the γδT17 cell response in lungs of Abt mice; here, more aggressive tumor development was observed, possibly related to a reduction in IL6 and IL23 expression there. Adding normal γδT cells or supplementing IL17 restored the impaired immune surveillance phenotype in Abt mice. Overall, our results demonstrated the importance of commensal bacteria in supporting the host immune response against cancer, defined an important role for γδT17 responses in the mechanism, and suggested deleterious effects of antibiotic treatment on cancer susceptibility and progression.

Bioinspired greigite magnetic nanocrystals: chemical synthesis and biomedicine applications

Large scale greigite with uniform dimensions has stimulated significant demands for applications such as hyperthermia, photovoltaics, medicine and cell separation, etc. However, the inhomogeneity and hydrophobicity for most of the as prepared greigite crystals has limited their applications in biomedicine. Herein, we report a green chemical method utilizing β-cyclodextrin (β-CD) and polyethylene glycol (PEG) to synthesize bioinspired greigite (Fe3S4) magnetic nanocrystals (GMNCs) with similar structure and magnetic property of magnetosome in a large scale. β-CD and PEG is responsible to control the crystal phase and morphology, as well as to bound onto the surface of nanocrystals and form polymer layers. The GMNCs exhibit a transverse relaxivity of 94.8 mM−1s−1 which is as high as iron oxide nanocrystals, and an entrapment efficiency of 58.7% for magnetic guided delivery of chemotherapeutic drug doxorubicin. Moreover, enhanced chemotherapeutic treatment of mice tumor was obtained via intravenous injection of doxorubicin loaded GMNCs.

Acetylsalicylic acid enhances the anti-inflammatory effect of fluoxetine through inhibition of NF-κB, p38-MAPK and ERK1/2 activation in lipopolysaccharide-induced BV-2 microglia cells

The latest advancements in neurobiological research provide increasing evidence that inflammatory and neurodegenerative pathways play an important role in depression. According to the cytokine hypothesis, depression could be due to the increased production of pro-inflammatory cytokines by microglia activation. Thus, using the BV-2 microglial cell line, the aim of the present study was to investigate whether fluoxetine (FLX) or acetylsalicylic acid (ASA) could inhibit this microglia activation and could achieve better results in combination. Our results showed that FLX could attenuate lipopolysaccharide (LPS)-induced production of interleukin-1β (IL-1β), the expression of the indoleamine 2,3 dioxygenase (IDO) enzyme and the depletion of 5-HT. Moreover, FLX could inhibit phosphorylation of nuclear factor-κB (NF-κB) and phosphorylation of p38 mitogen-activated protein kinase (MAPK), and the combined use with ASA could enhance these effects. Notably, the adjunctive agent ASA could also inhibit phosphorylation of extracellular-regulated kinase 1/2 (ERK1/2). Taken together, our results suggest that FLX may have some anti-inflammatory effects by modulating microglia activation and that ASA served as an effective adjunctive agent by enhancing these therapeutic effects.

Sequential Growth of NaYF4:Yb/Er@NaGdF4 Nanodumbbells for Dual-Modality Fluorescence and Magnetic Resonance Imaging

Upconversional core-shell nanostructures have gained considerable attention due to their distinct enhanced fluorescence efficiency, multifunctionality, and specific applications. Recently, we have developed a sequential growth process to fabricate unique upconversion core-shell nanoparticles. Time evolution of morphology for the NaYF4:Yb/Er@NaGdF4 nanodumbbells has been extensively investigated. An Ostwald ripening growth mechanism has been proposed to illustrate the formation of NaYF4:Yb/Er@NaGdF4 nanodumbbells. The hydrophilic NaYF4:Yb/Er@NaGdF4 core-shell nanodumbbells exhibited strong upconversion fluorescence and showed higher magnetic resonance longitudinal relaxivity (r1 = 7.81 mM-1 s-1) than commercial contrast agents (Gd-DTPA). NaYF4:Yb/Er@NaGdF4 nanodumbbells can serve as good candidates for high efficiency fluorescence and magnetic resonance imaging.

The effects of di 2-ethyl hexyl phthalate (DEHP) on cellular lipid accumulation in HepG2 cells and its potential mechanisms in the molecular level.

Abstract Diethylhexyl phthalate (DEHP) is suspected to be an inevitable factor related to metabolic disease. Our previous study demonstrated that excess DEHP could exacerbate non-alcoholic fatty liver disease (NAFLD) in SD rats. Addressing the terra incognita in DEHP-induced metabolic dysfunction, this study used HepG2 cells to investigate the potential mechanisms involved in DEHP-induced toxicity in vitro. The cells were established lipid overload model with oleic acid and BSA, then exposed to different concentrations (5, 10, 25, 50, 100 μmol/l DEHP) of DEHP for further analysis. The Oil Red O staining results showed that DEHP could promote lipid accumulation in cells. The level of superoxide dismutase (SOD) and malondialdehyde (MDA) changed suggested the balance of oxidative stress was disrupted. Additionally, western blot analysis showed that DEHP could promote the expression of peroxisome proliferator-activated receptor α (PPARα) and sterol regulatory element-binding protein 1c (SREBP-1c). By quantifying the expressions of the two proteins, it is of interest to determine that DEHP could promote lipid accumulation in hepatocytes via activating the SREBP-1c and PPARα-signaling pathway.

Di(2-ethylhexyl) phthalate exacerbates non-alcoholic fatty liver in rats and its potential mechanisms.

Di(2-ethylhexyl) phthalate (DEHP) may be responsible for inducing alterations similar to those encountered in nonalcoholic fatty liver disease (NAFLD). The aim of the present study was to investigate the detrimental effects and possible mechanisms of DEHP on fatty liver rats directly through triggering the disorder of liver lipid metabolism or indirectly by hepatotoxic effect. Considering these effects, DEHP may play a significant role in the pathogenesis of NAFLD. In this study, high-fat diet was used to induce NAFLD in rats for eight weeks. DEHP treated groups received (0.05, 5, 500 mg/kg daily, respectively) dose by gavage during the whole experiment period. Our results indicated that the detrimental effects of DEHP on high-fat diet induced NAFLDs were mediated via increasing lipid accumulation in the liver and causing lipid peroxidation and inflammation.

Di-(2-ethylhexyl) phthalate could disrupt the insulin signaling pathway in liver of SD rats and L02 cells via PPARγ

Abstract Di‐(2‐ethylhexyl)‐phthalate (DEHP), a ubiquitous industrial pollutant in our daily life, has been reported to cause adverse effects on glucose homeostasis and insulin sensitivity in epidemiological studies previously. Recently, it has been reported to be an endocrine disrupter and ligand to peroxisome proliferator activated receptor, which could influence the homeostasis of liver metabolic systems and contribute to the development of type‐2 diabetes. However, the potential mechanisms are not known yet. This study was designed to solve these problems with male SD rats and normal human hepatocyte line, L02 cells, exposed to DEHP for toxicological experiments. Adult male SD rats were divided into four groups, normal group fed with regular diets and three DEHP‐treated groups (dissolved in olive oil at doses of 0.05, 5 and 500 mg/kg body weight, respectively, once daily through gastric intubations for 15 weeks). L02 cells were divided into 6 groups, normal group with 5, 10, 25, 50, and 100 &mgr;mol/l DEHP groups. DEHP‐exposed rats exhibited significant liver damage, glucose tolerance, and insulin tolerance along with reduced expression of insulin receptor and GLUT4 proteins in the liver tissues. The results of in vitro experiments could determine that the DEHP‐induced activation of peroxisome proliferator activated receptor &ggr; (PPAR&ggr;) played a key role in the production of oxidative stress and down‐regulated expression of insulin receptor and GLUT4 proteins in L02 cells. This conclusion could be supported by the results of in vitro experiments, in which the cells were exposed to DEHP with GW9662 (PPAR&ggr; inhibitor). In general, these results highlight the key role of PPAR&ggr; in the process of insulin resistance induced by DEHP. HighlightsDEHP exacerbates insulin resistance both in liver tissues and cells.Expression of insulin receptor and GLUT4 were altered with PPAR&ggr;.DEHP can induce oxidative stress to disrupt the metabolic homeostasis.The dose of exposed DEHP is closed to daily exposure by human.Determine the key role of PPAR&ggr; to insulin resistance.