目的:优化粉尘螨1类变应原proDer f 1的酶解条件及探讨酶解产物的变应原性。方法:以水解度为指标,采用正交试验考察木瓜蛋白酶和胰蛋白酶水解proDer f 1蛋白的最佳工艺;采用间接酶联免疫吸附试验(ELISA)检测酶解产物的过敏原性。结果:...
详细信息
目的:优化粉尘螨1类变应原proDer f 1的酶解条件及探讨酶解产物的变应原性。方法:以水解度为指标,采用正交试验考察木瓜蛋白酶和胰蛋白酶水解proDer f 1蛋白的最佳工艺;采用间接酶联免疫吸附试验(ELISA)检测酶解产物的过敏原性。结果:温度是影响proDer f 1蛋白水解效果的主要因素,其中木瓜蛋白酶最佳水解条件为pH 6.5,温度60℃,水解时间4 h,酶用量4 000 U.g-1;胰蛋白酶最佳水解条件为pH 8.0,温度45℃,水解时间4 h,酶用量5 000 U.g-1;ELISA检测表明与proDer f 1变应原相比,木瓜蛋白酶水解产物和胰蛋白酶水解产物的过敏原性均显著减低,且胰蛋白酶水解产物的过敏原性较木瓜蛋白酶水解产物的过敏原性低。结论:优选的粉尘螨1类变应原proDer f 1蛋白的酶解工艺可行,且变应原酶解后,过敏原性有不同程度减低,尤以胰酶水解产物变化最为显著。
Restenosis is a critical complication of angioplasty and stenting. Restenosis is multifactorial, involving endothelial injury, inflammation, platelet activation, and vascular smooth muscle cell (VSMC) proliferation. T...
详细信息
Restenosis is a critical complication of angioplasty and stenting. Restenosis is multifactorial, involving endothelial injury, inflammation, platelet activation, and vascular smooth muscle cell (VSMC) proliferation. Thus, dietary strategies to prevent restenosis likely require the use of more than one agent. Resveratrol (R) and quercetin (0) are polyphenols that are known to exhibit vascular protective effects. We tested whether R and Q administered in the diet interact to inhibit vessel stenosis in mice with a carotid injury. B6.129 mice were administered a high-fat diet containing 21% fat and 0.2% cholesterol along with R (25 mg/kg), Q (10 mg/kg), or R + Q for 2 wk. A carotid injury was induced and the mice were again administered the enriched diet for 2 wk. Compared with the controls, B significantly decreased stenosis, assessed as an intima:media ratio, by 76%. Although 0 treatment alone exhibited no effect, it potentiated the effect of R in that treatment with R + 0 significantly decreased the intima:media ratio by 94%. Moreover, this effect was greater than that of R treatment alone (P < 0.05). Although treatments with R, Q, and R + Q significantly affected platelet activation and endothelial function, the responses observed for R + Q were less than additive. Specifically, the effects of R + Q were less than the sum of effects for treatments with R and Q alone. In contrast, treatment with R + Q exhibited more-than-additive effects on inflammatory markers and significant interactions between R and Q were observed. The presence of synergy between R and 0 was thus tested in cultures of VSMC and macrophages. Isobolographic analysis revealed that 2:1 molar ratios of R:Q exhibited synergistic inhibition of VSMC proliferation and macrophage chemotaxis. In conclusion, in combination, R and Q can interact to reduce the extent of restenosis, perhaps due to their synergistic inhibition of VSMC proliferation and inflammation. J. Nutr. 142: 1487-1494, 2012.
心智游移是一种常见的非自主内源性意识体验,是意识流的重要组成部分,它的存在提示非感官意识在人类意识经验中的重要地位。目前心智游移研究中一个仍待解决的问题是:同样是注意以非随意的方式从当前任务上转移至无关信息,分心(distraction)表现为个体不能抑制对外界无关刺激的加工,而心智游移表现为个体不能抑制对内源性无关信息的加工,心智游移和分心的心理机制是否相同?本研究将从任务知觉负荷和个人特质对心智游移频率的影响角度回答这一问题。注意负荷理论(The load theory of attention)指出当前任务的知觉负荷水平是决定个体是否能够集中注意、忽视无关刺激干扰的一个决定性因素,高知觉负荷能够抑制个体对无关刺激的加工,消除分心倾向性的个体差异,即高知觉负荷下高分心倾向个体和低分心倾向个体抵抗干扰刺激的能力差异不再显著。心智游移倾向性也是一种个人特质,并且高知觉负荷也会降低个体的心智游移频率,那么,心智游移倾向的个体差异是否也像分心倾向性的个体差异一样会受到任务知觉负荷的调节?为了探讨任务负荷对心智游移个体差异的影响,实验一设置三种知觉负荷水平的实验条件,检验用心智游移特质问卷区分出来的高、低心智游移倾向特质的个体在实验任务中发生的心智游移频率是否仍然具有稳定的个体差异。结果表明,随着任务知觉负荷水平的提高,心智游移的发生频率显著下降,然而高心智游移倾向特质的个体始终比低心智游移倾向特质的个体报告了更多的心智游移。这一研究结果提示高知觉负荷虽然会减少心智游移的发生,但是难以消除心智游移倾向的个体差异。心智游移具有与分心不同的心理机制。实验二在实验一的基础上,利用f MRI(功能核磁共振)技术,通过控制心智游移个体差异和任务知觉负荷,从激活和脑网络两个角度研究心智游移的神经基础,验证了默认网络脑区直接参与心智游移活动的观点,并且第一次从功能连接的角度揭示了默认网络是心智游移倾向个体差异的神经基础。
Duodenal cytochrome b (Dcytb, Cybrd1) is a ferric reductase localized in the duodenum that is highly upregulated in circumstances of increased iron absorption. To address the contribution of Dcytb to total duodenal fe...
详细信息
Duodenal cytochrome b (Dcytb, Cybrd1) is a ferric reductase localized in the duodenum that is highly upregulated in circumstances of increased iron absorption. To address the contribution of Dcytb to total duodenal ferric reductase activity as well as its wider role in iron metabolism, we first measured duodenal ferric reductase activity in wild-type (WT) and Dcytb knockout (Dcytb(-/-)) mice under 3 conditions known to induce gut ferric reductase: dietary iron deficiency, hypoxia, and pregnancy. Dcytb(-/-) and WT mice were randomly assigned to control (iron deficiency experiment, 48 mg/kg dietary iron;hypoxia experiment, normal atmospheric pressure;pregnancy experiment, nonpregnant animals) or treatment (iron deficiency experiment, 2-3 mg/kg dietary iron;hypoxia experiment, 53.3 kPa pressure;pregnancy experiment, d 20 of pregnancy) groups and duodenal reductase activity measured. We found no induction offerric reductase activity in Dcyt(-/-) mice under any of these conditions, indicating there are no other inducible ferric reductases present in the duodenum. To test whether Dcytb was required for iron absorption in conditions with increased erythropoietic demand, we also measured tissue nonheme iron levels and hematological indices in WT and Dcytb(-/-) mice exposed to hypoxia. There was no evidence of gross alterations in iron absorption, hemoglobin, or total liver nonheme iron in Dcytb(-/-) mice exposed to hypoxia compared with WT mice. However, spleen nonheme iron was significantly less (6.7 +/- 1.0 vs. 12.7 +/- 0.9 nmol . mg tissue(-1);P < 0.01, n = 7-8) in hypoxic Dcytb(-/-) compared with hypoxic WT mice and there was evidence of impaired reticulocyte hemoglobinization with a lower reticulocyte mean corpuscular hemoglobin (276 +/- vs. 283 +/- 2 g . L-1;P < 0.05, n = 7-8) in normoxic Dcytb(-/-) compared with normoxic WT mice. We therefore conclude that DCYTB is the primary iron-regulated duodenal ferric reductase in the gut and that Dcytb is necessary for optima
Conservation of agricultural and forestry land has taken on a new urgency as development patterns have exploded over the past few decades, due to demand for residential, industrial and commercial land uses in the U.S....
详细信息
Conservation of agricultural and forestry land has taken on a new urgency as development patterns have exploded over the past few decades, due to demand for residential, industrial and commercial land uses in the U.S. As a result, numerous land conservation programs have been implemented over the years. Current Use Property Taxation is one of the land conservation programs that was initiated in the 1960s, introducing some property tax relieffor landowners who wished to keep undeveloped productive land in current use without developing it for more urbanized uses. The substantial property tax relief landowners receive by enrolling land in the Current Use program was believed to be the main determinant in avoiding property tax induced land development. However, the forgone property tax revenue was a concern for state and local governments. In order to recapture forgone tax revenues and also to discourage enrollment of land for short-term property tax gains, withdrawal penalties and restrictions on land development were introduced. Current Use program features are not consistent across states and the reasons for interstate differences are not clear. This dissertation explores the factors that lead to such variations across states and whether such variations in fact lead to differences in land development. One chapter focuses on detailing the factors that lead New Hampshire landowners to enroll land in the program, while another chapter explores the factors that determined differences in program features across states. The last chapter explores whether the Current Use program is effective in slowing the land development in the U.S. by considering a town-level case study from New Hampshire and also a state level analysis.
暂无评论