Impact of Cross-Linked Chitosan Sublayer Structure on the Performance of TFC FO PAN Nanofiber Membranes.

Polyacrylonitrile (PAN) is a popular material in membrane field because of its excellent mechanical property, thermal stability, and chemical resistance. Unfortunately, PAN nanofibers produced by electrospinning are not suitable for interfacial polymerization process directly due to its hydrophobicity and large average pore size. In this work, the cross-linked chitosan (CS) solution was coated on the nanofiber surface to fabricate a sublayer, based on which thin-film composite (TFC) membranes were prepared using m-phenylenediamine and 1,3,5-trimesoyl chloride as the monomers. The impact of the different sublayers on the performances of TFC PAN nanofiber membranes for forward osmosis (FO) was studied by varying cross-linked CS concentrations. The results indicated that the increased CS concentration not only led to the relatively denser polyamide layer, but also changed its morphology. In the reverse osmosis process, NaCl rejection increased from 46.5 to 83.5%. Salt flux from feed solution to draw solution decreased from 25.8 to 8.9 g·m-2·h-1 (0.1 M NaCl solution as feed, 2 M glucose solution as draw solution, FO mode). This study found that the sublayer had noteworthy impact on the separation layer and helped us to pave the way to design high-performance FO membranes.

Effect of glucocorticoid in mice of asthma induced by ovalbumin sensitisation and RSV infection.

OBJECTIVE: To investigate the inflammatory changes and the airway hyper-responsiveness in the asthma mouse model infected by respiratory syncytial virus and elucidate the relationship between the infection and the effect of glucocorticoid. METHODS: 60 BALB/c mice were randomly divided into 6 groups. One of these is the control group; the others are the OVA/sham group, the OVA/sham +Dex group, the PBS/RSV group, the OVA/RSV group and the OVA/RSV+Dex group. The airway resistance was measured using a sealed body plethysmograph. Pathological slides were stained with hematoxylin-eosin, and the peribronchial inflammation was observed microscopically. The concentrations of IL-4, IFN-gamma, TGF-beta1 in lung tissues were detected by ELISA. RESULTS: Compared with the control group, the degree of the airway inflammation and hyperresponsiveness and the concentrations of IL-4/IFN-gamma, TGF-beta1 in all four OVA groups increased significantly. And there was a statistically significant difference between the OVA/sham group and the OVA/sham+Dex group, and between the OVA/RSV group and the OVA/RSV+Dex group respectively. Compared with the OVA/RSV group, there was an obvious aggravation of airway inflammation and hyper-responsiveness in the OVA/RSV+Dex group. CONCLUSIONS: Glucocorticoid significantly reduces airway inflammation and hyper-responsiveness induced by repetitive OVA challenge in the mouse model of asthma. However, the significant decrease in Th1 and increase in Th2 inflammation and aggravation of airway hyper-responsiveness in the mice in OVA/RSV group show that they are not sensitive to glucocorticoid. The effects of infection with RSV on the mouse model of asthma could be the cause of the glucocorticoid resistance during the therapy.

[The relationship between transforming growth factor-beta1, platelet derived growth factor and airway remodeling in eosinophilic bronchitis].

OBJECTIVE: To study the relationship between the expression of transforming growth factor-beta(1) (TGF-beta(1)) and platelet derived growth factor (PDGF) and airway remodeling in eosinophilic bronchitis (EB). METHODS: Bronchial biopsy specimens were obtained from 12 patients with EB (A group), 10 asthmatic patients (B group) and 10 patients (C group) with peripheral lung cancer in early stage. The subepithelial basement membrane (SBM) thickness was measured by light microscopy using HE staining. The expressions of TGF-beta(1) and PDGF in the bronchial mucosa were examined by immunostaining. RESULTS: The SBM of A group [(6.3 +/- 1.4) micro m] was significantly thicker than that of C group [(4.1 +/- 1.2) micro m, P < 0.05], but significantly thinner than that of B group [(8.2 +/- 1.5) micro m]. The numbers of positive cells for TGF-beta(1) and PDGF in A group (59 +/- 9, 47 +/- 7 respectively) and B group (85 +/- 12, 76 +/- 11, respectively) were significantly higher than those in C group (31 +/- 4, 20 +/- 3, respectively), and were positively correlated with SBM thickness (r = 0.76, 0.52, P < 0.05). CONCLUSION: These results suggest that TGF-beta(1) and PDGF expressions in bronchial mucosa may play a role in bronchial subepithelial fibrosis in EB patients.