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991.
One of the plausible ways to prevent the reactive oxygen species (ROS)-mediated cellular injury is dietary or pharmaceutical augmentation of endogenous antioxidant defense capacity. In this study, we investigated the neuroprotective effect of fucoidan on H(2)O(2)-induced apoptosis in PC12 cells and the possible signaling pathways involved. The results showed that fucoidan inhibited the decrease of cell viability, scavenged ROS formation and reduced lactate dehydrogenase release in H(2)O(2)-induced PC12 cells. These changes were associated with an increase in superoxide dismutase and glutathione peroxidase activity, and reduction in malondialdehyde. In addition, fucoidan treatment inhibited apoptosis in H(2)O(2)-induced PC12 cells by increasing the Bcl-2/Bax ratio and decreasing active caspase-3 expression, as well as enhancing Akt phosphorylation (p-Akt). However, the protection of fucoidan on cell survival, p-Akt, the Bcl-2/Bax ratio and caspase-3 activity were abolished by pretreating with phosphatidylinositol-3-kinase (PI3K) inhibitor LY294002. In consequence, fucoidan might protect the neurocytes against H(2)O(2)-induced apoptosis via reducing ROS levels and activating PI3K/Akt signaling pathway.  相似文献   
992.
Liu YL  Yang J  Zheng J  Liu DW  Liu T  Wang JM  Wang CN  Wang MW  Tian QB 《Gene》2012,501(2):188-192

Purpose

The Paraoxonase 1 (PON1) has been studied as a potential candidate gene for Parkinson's disease risk, but direct evidence from genetic association studies remains inconclusive. We performed a meta-analysis pooling data from all relevant studies in order to determine the effects of two PON 1 polymorphisms (L55M and Q192R) on Parkinson's disease.

Methods

We applied a random effects to combine odds ratio (OR) and 95% confidence intervals. Q statistic was used to evaluate the homogeneity, and Egger's test and Funnel plot were used to assess publication bias. In secondary analyses, we examined dominant and recessive models as well.

Results

Concerning the PON1 L55M polymorphism, we identified 9 eligible studies (a total of 2582 cases and 3997 controls). The random effects pooled OR was OR = 1.29, (0.90, 1.84). Concerning the Q192R polymorphism, we identified 7 eligible studies (a total of 2582 cases and 3997 controls). The random effects pooled OR was OR = 1.08(0.81, 1.43). Analysis with dominant and recessive genetic models yielded the same inferences as genotype-based comparisons for both of the two polymorphisms.

Conclusion

The results of this meta-analysis suggested that both PON1 L55M and Q192R were not responsible for PD.  相似文献   
993.
Follicular dendritic cells emerge from ubiquitous perivascular precursors   总被引:1,自引:0,他引:1  
The differentiation of follicular dendritic cells (FDC) is essential to the remarkable microanatomic plasticity of lymphoid follicles. Here we show that FDC arise from ubiquitous perivascular precursors (preFDC) expressing platelet-derived growth factor receptor β (PDGFRβ). PDGFRβ-Cre-driven reporter gene recombination resulted in FDC labeling, whereas conditional ablation of PDGFRβ(+)-derived cells abolished FDC, indicating that FDC originate from PDGFRβ(+) cells. Lymphotoxin-α-overexpressing prion protein (PrP)(+) kidneys developed PrP(+) FDC after transplantation into PrP(-) mice, confirming that preFDC exist outside lymphoid organs. Adipose tissue-derived PDGFRβ(+) stromal-vascular cells responded to FDC maturation factors and, when transplanted into lymphotoxin β receptor (LTβR)(-) kidney capsules, differentiated into Mfge8(+)CD21/35(+)FcγRIIβ(+)PrP(+) FDC capable of trapping immune complexes and recruiting B cells. Spleens of lymphocyte-deficient mice contained perivascular PDGFRβ(+) FDC precursors whose expansion required both lymphoid tissue inducer (LTi) cells and lymphotoxin. The ubiquity of preFDC and their strategic location at blood vessels may explain the de novo generation of organized lymphoid tissue at sites of lymphocytic inflammation.  相似文献   
994.
995.
An iterative combinatorial mutagenesis (ICM) strategy was used to engineer deacetoxycephalosporin C synthase of Streptomyces clavuligerus (scDAOCS) for improved activity toward penicillin G. Seven mutational sites were repeatedly combined onto a starter mutant (C155Y Y184H V275I C281Y) of scDAOCS. Eleven improved combinatorial mutants were identified from 24 mutants in four rounds of ICM.  相似文献   
996.
997.
The purpose of this study was to develop poly(ethylene glycol)-coated nanostructured lipid carriers (PEG-NLC) for parenteral delivery of oridonin (ORI) to prolong drug circulation time in blood. Oridonin-loaded PEG-NLC (ORI-PEG-NLC) consisting of PEG(2000)-stearate, glycerol monostearate and medium chain triglycerides were prepared by emulsion-evaporation and low temperature-solidification technique. Oridonin-loaded NLC (ORI-NLC) were also prepared as control. ORI-PEG-NLC were observed by transmission election microscope and the morphology was in rotiform shape. The mean particle size of ORI-PEG-NLC was 329.2 nm and entrapment efficacy was 71.18%. The results of differential scanning calorimetry and X-ray diffraction revealed a low-crystalline structure of ORI and verified the incorporation of ORI into the nanoparticles. In vitro drug release of ORI-PEG-NLC exhibited biphasic drug release patterns with burst release initially and prolonged release afterwards. Pharmacokinetic analysis showed that the mean residence time of ORI-PEG-NLC was prolonged and AUC (area under tissue concentration-time curve) value was also improved compared with ORI-NLC and ORI solution. In conclusion, ORI-PEG-NLC could be a potential carrier to get prolonged retention time of oridonin in blood.  相似文献   
998.
Y Zhao  J He  X Han  X Tian  M Deng  W Chen  B Jiang 《Carbohydrate polymers》2012,90(2):988-992
A new guar gum derivative containing amino group was synthesized through nucleophilic substitution of p-toluenesulfonate activated hydroxypropyl guar gum with ethanolamine. For the preparation of p-toluenesulfonate esters hydroxypropyl guar gum, the results showed that the reaction rate was optimal at 25°C and the reaction could reach equilibrium state when it was carried out for 10h at 25°C. For the nucleophilic substitution of tosyl group with ethanolamine, the reaction was completed after 10h reaction at 50°C. The structures of products were characterized by NMR and FT-IR spectroscopy. The results showed that the p-toluenesulfonate esters can be effectively substituted by ethanolamine to form the hydroxyethyl amino hydroxypropyl guar gum (EAHPG). The content of nitrogen of EAHPG was determined by acid-base titration and element analysis.  相似文献   
999.
This study evaluates the bleaching efficiency of the hydrogen peroxide bleaching process combined with laccase-mediated system pretreatment (LMS-HPBP) in the treatment of scoured cotton fabric. By changing the factors of laccase-mediated system pretreatment and the hydrogen peroxide bleaching process and examining the subsequent whiteness value and retained tensile strength of the samples, we find three LMS-HPBP processes that are more environment friendly than the conventional hydrogen peroxide bleaching process (CHPBP): (i) bleaching with lower dosage of hydrogen peroxide; (ii) bleaching at reduced temperature; (iii) bleaching for shortened duration. Whiteness, retained tensile strength and K/S values of cotton fabric samples treated by i-iii processes were similar to or higher than those by CHPBP. X-ray diffraction (XRD) analysis also demonstrated that the three processes rendered fabric of both lower crystallinity and bigger crystallite size than those by CHPBP. In addition, the "green" short-flow process was developed to treat cotton fabric and the results obtained shows this method is feasible as a new energy-saving process.  相似文献   
1000.
Zhu B  Liu H  Tian WX  Fan XY  Li B  Zhou XP  Jin GL  Xie GL 《Journal of bacteriology》2012,194(5):1280-1281
Stenotrophomonas maltophilia is an endophyte which plays important roles in agricultural production as a plant growth-promoting bacterium. Here, we present the draft genome sequence of strain RR-10, which was isolated from a rice root in a rice field of China.  相似文献   
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