目的通过小鼠梗黄及胆汁内外引流模型,观察小鼠肠黏膜胆汁酸核受体法尼酯衍生物X受体(Farnesoid X receptor,FXR)和病原模式识别受体Toll样受体4(Toll-like receptor 4,TLR4)的表达变化并探讨两者之间的相互作用。方法采用成年雄性昆明...目的通过小鼠梗黄及胆汁内外引流模型,观察小鼠肠黏膜胆汁酸核受体法尼酯衍生物X受体(Farnesoid X receptor,FXR)和病原模式识别受体Toll样受体4(Toll-like receptor 4,TLR4)的表达变化并探讨两者之间的相互作用。方法采用成年雄性昆明小鼠60只随机分为四组,即梗黄组(OJ组)、胆汁外引流组(ED组)、胆汁内引流组(ID组)和假手术组(SH组),每组15只。利用蛋白质印迹分析(Western blotting)和实时荧光定量PCR(qRT-PCR)法检测回肠黏膜FXR与TLR4蛋白及其mRNA的表达。此外,取40只小鼠随机分为OJ、ED、ID和SH四组,每组10只,各组中再用FXR激动剂GW4064(n=5)灌胃干预,羧甲基纤维素钠CMC-Na(n=5)作为对照。结果小鼠胆道梗阻后,肠黏膜FXR蛋白及其mRNA表达较SH组明显升高,肠黏膜TLR4蛋白及其mRNA表达较SH组明显下降。胆汁外引流术后,FXR蛋白表达较OJ组明显下降而其mRNA表达升高,TLR4蛋白及其mRNA表达明显升高。胆汁内引流术后,FXR蛋白及其mRNA表达较OJ组下降,TLR4蛋白及其mRNA表达明显上升,效果均好于外引流(P<0.05)。安慰剂灌胃和上述未行灌胃的小鼠的TLR4表达趋势基本一致,而利用FXR激动剂灌胃后,四组小鼠TLR4表达差异消失(P>0.05)。结论小鼠梗黄形成后,肠道FXR升高,TLR4下降,胆汁内引流和外引流均可逆转这些改变,但内引流效果好于外引流。肠道内胆汁酸是引起这些变化的关键。展开更多
Accurate measurement of optical extinction of atmospheric aerosols is important for quantifying the direct climate effects of aerosols. A portable cavity ringdown spectrometer utilizing a modulated multimode blue diod...Accurate measurement of optical extinction of atmospheric aerosols is important for quantifying the direct climate effects of aerosols. A portable cavity ringdown spectrometer utilizing a modulated multimode blue diode laser (linewidth ~0.2 nm) is developed to measure the aerosol optical extinction. Laboratory generated ammonia sulfate particles (<1 μm in diameter) are characterized, with good agreements between the experimental measurements and Mie theory calculations. An optical extinction detection sensitivity of 0.24 Mm-1 (1σ) is achieved. Measurements of ambient aerosols are also carried out. This study demonstrates the feasibility of a compact, multimode diode laser cavity ringdown spectrometer for sensitive measurements of the optical extinction of atmospheric aerosols.展开更多
基金supported by the US National Science Foundation (CHE1214157)W. M. Keck Foundation
文摘Accurate measurement of optical extinction of atmospheric aerosols is important for quantifying the direct climate effects of aerosols. A portable cavity ringdown spectrometer utilizing a modulated multimode blue diode laser (linewidth ~0.2 nm) is developed to measure the aerosol optical extinction. Laboratory generated ammonia sulfate particles (<1 μm in diameter) are characterized, with good agreements between the experimental measurements and Mie theory calculations. An optical extinction detection sensitivity of 0.24 Mm-1 (1σ) is achieved. Measurements of ambient aerosols are also carried out. This study demonstrates the feasibility of a compact, multimode diode laser cavity ringdown spectrometer for sensitive measurements of the optical extinction of atmospheric aerosols.