Visible light induced dextran-methacrylate hydrogel formation using (−)-riboflavin vitamin B2 as a photoinitiator and L-arginine as a co-initiator

The objective of this study is to examine the feasibility of using visible light to form gels from polysaccharide precursors. Hydrogel formation by visible light irradiation would be very beneficial because visible light is a benign light source and ready available when compared with other light sources such as UV. Dextran-methacylate was synthesized and photocrosslinked using (−)-riboflavin as a photoinitiator and L-arginine as a co-initiator under the visible light. The effect of various concentrations of (−)-riboflavin and L-arginine on the photo-crosslinking of dextran-methacrylate hydrogel was investigated. The fabricated hydrogel was characterized by FT-IR and SEM. The photoinitiator [(−)-riboflavin] and co-initiator (L-arginine) as well as dextran precursor are completely biocompatible. The optimum condition for the biocompatible dextran-based hydrogel formation under the harmless light source (visible light) was elucidated in this study. In general, the (−)-riboflavin, 0.01–0.5 %, and L-arginine, 5–20 % of the weight of dextran-methacrylate were the best condition in forming dextran-based hydrogels under the visible light. The three-dimensional hydrogel structure was verified by SEM morphology of swollen hydrogels. Photocrosslinking under the visible light source would enlarge the applications of this type of photocrosslinking in the biomedical area (e.g., eyes or other light-sensitive organs).     

甘蔗生产过程葡聚糖的形成与检测研究进展

甘蔗生产过程出现的葡聚糖主要是甘蔗感染肠膜明串珠菌消耗蔗糖后的代谢产物.葡聚糖的形成与甘蔗品种、田间环境(种植方式、温度及湿度、日照、土壤条件、夹杂物)、损伤程度(顽性甘蔗、收获方式)等因素有关,其含量可通过特异性葡聚糖单抗试剂盒快速、准确测定.葡聚糖是评价甘蔗新鲜度直接、可靠的指标.     

亚临界水法催化制备微分子右旋糖酐工艺研究

[目的]优化亚临界水法催化制备微分子右旋糖酐的工艺。[方法]以右旋糖酐20为原料,采用亚临界水法催化制备微分子右旋糖酐,并在单因素试验的基础上,通过正交试验对右旋糖酐20水解的工艺条件进行优化。[结果]各因素对右旋糖酐20水解影响的大小顺序为温度时间固液比搅拌转速。制备微分子右旋糖酐优选条件为反应温度170℃,反应1.5 h,固液比为0.6 g/ml,搅拌转速为200 r/min,制得微分子右旋糖酐重均分子量(Mw)为6 132,分布宽度(D)为1.67。[结论]该研究为制备微分子右旋糖酐提供了参考。     

The effect of hypertonic saline solution on vasodilatation of the superior sagittal sinus using magnetic resonance imaging in normovolemic dogs

Several animal studies have demonstrated the beneficial effects of hypertonic saline (HSS) on cerebral blood flow, intracranial pressure and brain water content. This study aimed to investigate, using magnetic resonance imaging, whether a small volume of HSS is superior to dextran in vasodilatation of cerebral vessels and reduction of cerebrospinal fluids in dogs. HSS induced a significant expansion of the cross-section of the superior sagittal sinus in the axial transverse section of the pituitary and a decrease in cerebrospinal fluid area in the axial transverse section of the epencephalon more than dextran 40 did (p<0.001, respectively). However, the relative plasma volume in the dog which received dextran 40 was significantly higher after t=30min than in the HSS group (p<0.001). Therefore, it is suggested that HSS might be superior to colloid solutions in improving cerebral circulation, whereas dextran 40 is superior to HSS in enhancing systemic circulation in dogs.     

桑黄菌袋提取物对葡聚糖硫酸钠诱导小鼠结肠炎的防治作用

为了将人工栽培桑黄后的废弃物菌袋应用于动物疾病防控,研究桑黄菌袋提取物(SHM)对葡聚糖硫酸钠(DSS)诱导的小鼠结肠炎的防治效果及其作用机制。结果显示:与正常对照组相比,DSS组的小鼠体质量极显著降低(P<0.01),血浆中白细胞介素1β(IL-1β)和髓过氧化物酶(MPO)的含量极显著升高(P<0.01),结肠长度极显著变短(P<0.01),结肠组织增厚水肿,大量的炎性细胞浸润,结肠组织Toll样受体4(TLR4)、肿瘤坏死因子受体相关因子6(TRAF6)、泛素结合酶13(Ubc13)、细胞核因子κB p65(NFκB p65)、肿瘤坏死因子α(TNF-α)、IL-1β、白细胞介素6(IL-6)、核苷酸结合寡聚化结构域样受体热蛋白结构域亚家族成员3(NLRP3)和凋亡相关斑点样蛋白(ASC)的基因表达极显著升高(P<0.01);与DSS组相比,给予375 mg/(kg·d) SHM的小鼠体质量显著增加(P<0.05),血浆中IL-1β和MPO含量显著降低(P<0.05),结肠长度显著增加(P<0.05),结肠组织形态得到恢复,但给予125 mg/(kg·d) SHM的小鼠上述指标变化不显著(P>0.05);与DSS组相比,给予375 mg/(kg·d) SHM的小鼠结肠中IL-1β、IL-6和NLRP3基因的表达显著降低(P<0.05)。上述结果表明,SHM在一定剂量下对DSS诱导的小鼠结肠炎有良好的防治效果,其防治作用可能是通过降低TLR-4通路下游蛋白IL-1β和IL-6的基因表达,以及调控NLRP3的表达以降低IL-1β蛋白的活化来实现的。     

Expression of hepatocyte nuclear factor 4α in experimental colitis in mice

AIM: To investigate the role of hepatocyte nuclear factor 4α (HNF4α) in the pathogenesis of ulcerative colitis (UC) by measuring the expression of HNF4α in the colon tissues in experimental colitis mice. METHODS: BALB/c mice were exposed to 2% or 2.5% (W/V) dextran sulfate sodium (DSS) to induce acute colitis, and the severity of colitis was assessed by observation of disease activity index (DAI), histological injuries and inflammatory cytokines. The correlation between the expression of HNF4α and the severity of disease as well as E-cadherin (E-CAD), junctional adhesion molecule 1 (JAM-1) and desmocollin 2 (DSC-2) was analyzed. RESULTS: Compared with the normal controls, DAI, histological injuries and the mRNA expression of inflammatory cytokines in DSS-treated mice were significantly elevated (P<0.05). The expression of HNF4α at protein and mRNA levels was significantly decreased (P<0.01). The result of Pearson analysis indicated an inverse correlation between the protein expression of HNF4α and the severity of disease (P<0.01). The positive correlation between the mRNA expression of HNF4α and E-CAD/JAM-1/DSC-2 (P<0.01) was also observed. CONCLUSION: There is a close relationship between the expression of HNF4α and the severity of colitis as well as the intercellular linking proteins. The low expression of HNF4α in intestine might aggravate the function of intestinal mucosal barrier, thus promoting the development of UC.     

Effect of mesalazine on Th1, Th17 and Treg cells in mice with DSS-induced ulcerative colitis

AIM: To investigate the effect of mesalazine treatment on regulation of Th1, Th17 and Treg cells in mice with dextran sulfate sodium (DSS)-induced ulcerative colitis (UC). METHODS: The expression of IL-17, IFN-gamma and Foxp3 in the peripheral blood mononuclear cells (PBMC) and intestinal mucosa lamina propria mononuclear cells (LPMC) of DSS-induced UC mice was detected by flow cytometry analysis. The effect of mesalazine treatment on regulaiton of Th1, Th17 and Treg cells in the mice with DSS-induced ulcerative colitis was examined.RESULTS: The expression of IL-17, IFN-γ and Foxp3 on CD4+T cells were significantly higher in the PBMC of DSS-induced mice than those in control group. CD4+ IFN-γ+T cells and CD4+ Foxp3+T cells were higher in LPMC than those in control group, except CD4+IL-17+T cells. Moreover, the Th1, Th17 and Treg cells were higher in DSS group than those in control group in LPMC. However, only Tregs was higher in PBMC. Pre-treatment with mesalazine significantly decreased the number of Th17, Th1 and Treg cells of UC model mice both in PBMC and LPMC.CONCLUSION: The Th1, Th17 and Tregs cells in DSS-induced mice were significantly higher than those in control mice, suggesting that CD4+T cell subsets play an important role in the pathogenesis of UC. Mesalazine may play a role in the treatment of UC by regulating the Th1, Th17 and Tregs cells.