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121.
Antioxidant properties of ursodeoxycholic acid   总被引:5,自引:0,他引:5  
We have investigated potential antioxidant properties of the clinically relevant bile acid UDCA, which reaches therapeutic concentrations up to 0.09 and 29 mM, respectively, in human plasma and bile. UDCA was an excellent scavenger of OHz.rad; generated by FeCl(3)-EDTA, H(2)O(2) and ascorbate in the deoxyribose oxidation test, showing IC(min) and IC(50) values of 0.02 and 0.2 mM, respectively, and a second-order rate constant for reaction with OHz.rad; of 2+/-0.1 x 10(10)M(-1)s(-1). Notably, the drug could enhance at 1.5 mM concentration the antioxidant capacity of human bile against OHz.rad;-induced deoxyribose oxidation. UDCA also showed antioxidant effects in the deoxyribose test performed with nonchelated iron ions, such as Fe(2+) plus H(2)O(2) (IC(min): 7 mM, IC(50): 20 mM) or Fe(3+) plus H(2)O(2) and ascorbate (IC(min): 0.3 mM, IC(50): 5 mM), and inhibited ferrozine-Fe(2+) and desferrioxamine-Fe(3+) complexes formation with IC(50) values of, respectively, 12 and 0.3 mM, indicating that the drug interacts more with iron(III) than with iron(II). Moreover, UDCA significantly inhibited phospholipid liposome peroxidation induced by the OHz.rad;-generating system FeCl(3)-EDTA, H(2)O(2) and ascorbate (IC(min): 0.75 mM, IC(50): 3 mM), and by peroxyl radicals generated in the aqueous phase by AAPH (IC(min): 8 mM, IC(50): 14 mM). UDCA, even at 25 mM concentration, was ineffective on the lipoperoxidation mediated by Fe(2+) alone, but at the same concentration counteracted significantly that by Fe(3+) plus ascorbate, further pointing to its preferential antioxidant interaction with iron(III).In conclusion, UDCA has direct antioxidant properties, which are especially relevant against Fe(3+)- and OHz.rad;-dependent biomolecular oxidative damage; such properties are evident at therapeutically relevant drug concentrations, suggesting that UDCA could act as an antioxidant in vivo.  相似文献   
122.
Agarwood is an important non-timber forest product widely used in religious and cultural activities as perfume and fragrance and as traditional medicine in Asia. The high value of agarwood and the inflated consuming market have led to constant rising of the prices. In general, the price of the agarwood is determined according to its quality, which can be divided into different grades. But up to now, there is not any standard quality grading system which could be used overwhelmingly throughout the agarwood producing, commerce and consumption. Therefore, we reviewed agarwood in diversified grading indexes, systems and methods.  相似文献   
123.
目的:探讨大株红景天胶囊对颈动脉不稳定斑块气虚血瘀证的干预及抗氧化、抗炎和抗血栓形成的作用机制。方法:将符合要求的123例患者,随机按数字表法分为对照组61例和观察组62例。对照组给予抗血小板和调节血脂药物治疗,口服阿司匹林肠溶片,0.1 g/次,1次/d;瑞舒伐他汀钙胶囊,10 mg/次,1次/d。观察组西药使用同对照组,并给予大株红景天胶囊,4粒/次,3次/d。两组疗程均为患者每2周门诊随访1次,连续观察16周。采用彩色多普勒超声测量颈动脉内膜中层厚度(IMT),斑块数量和斑块大小;检测治疗前后甘油三酯(TG),总胆固醇(TC),高密度脂蛋白胆固醇(HDL-C)和低密度脂蛋白胆固醇(LDL-C)水平;进行气虚血瘀证评分;检测治疗前后超氧化物歧化酶(SOD),丙二醛(MDA),超敏C反应蛋白(hs-CRP),同型半胱氨酸(Hcy),基质金属蛋白酶-2(MMP-2),MMP-9,基质金属蛋白酶组织抑制剂-2(TIMP-2),血小板α-颗粒膜蛋白-140(GMP-140),血小板表面P-选择素(CD62 p),溶酶体颗粒糖蛋白(CD63)和血管性假血友病因子(v WF)水平。结果:治疗后,观察组患者IMT薄于对照组、斑块数量少于对照组、斑块大小积分小于对照组(P0.01);治疗后,观察组患者LDL-C低于对照组(P0.01),HDL-C高于对照组(P0.01),气虚血瘀证评分低于对照组(P0.01);观察组患者血清hs-CRP,Hcy,MMP-2,MMP-9均低于对照组,TIMP-2水平高于对照组(P0.01);观察组患者SOD水平高于对照组,MDA水平低于对照组(P0.01);观察组患者GMP-140,v WF,CD62 p和CD63水平均低于对照组(P0.01)。结论:在抗血小板和调节血脂药物治疗的基础上,加服大株红景天胶囊,对治疗气虚血瘀型颈动脉不稳定斑块,具有缩小或减少颈动脉斑块的作用,能调节脂代谢,改善中医证候症状,并具有抗氧化、抗炎和抗血栓形成的作用。  相似文献   
124.
目的 探讨肠复康诱导人大肠癌HT2 9裸小鼠移植瘤细胞分化的作用。方法 建立人大肠癌HT2 9裸小鼠皮下移植瘤模型 ,用电子天平测量移植瘤的质量 ,苏木精—伊红染色观察瘤组织细胞的形态结构 ,结合图像分析系统半定量检测瘤细胞核分裂数及其形态计量学改变 ,并使用逐步引入剔出模型进行多元线性回归分析。结果 与模型组比 ,肠复康组和西药组均使移植瘤瘤体质量明显减轻 (P <0 .0 5或 0 .0 0 1) ,瘤组织细胞异型性降低 ,核分裂数、核仁面积 /核面积明显减少 (P <0 .0 0 1) ,且肠复康组的作用比西药组更为明显 (P <0 .0 0 1) ;同时 ,肠复康组瘤细胞核平均灰度明显降低 (P <0 .0 0 1) ,细胞核形状因子增高 (P <0 .0 5 ) ,西药组以上改变不明显 (P >0 .0 5 )。回归分析结果 ,移植瘤质量与瘤细胞核平均灰度和核分裂数呈明显正相关。结论 肠复康能抑制人大肠癌HT2 9裸小鼠移植瘤的增殖 ,其机制之一可能是逆转瘤细胞的异型性 ,诱导瘤细胞的重新分化。  相似文献   
125.
目的:观察头针、耳针结合醒脑开窍综合疗法治疗脑出血昏迷患者促苏醒及言语、肢体功能恢复的临床疗效.方法:将脑出血致重度脑损伤患者随机抽取56例分成两组,综合治疗组36例,单纯体针组20例,进行疗效观察.结果:治疗组良好率69.4%.对照组良好率40%,差异有显著性(P<0.05).结论:头针、耳针结合醒脑开窍综合疗法对脑出血昏迷患者促苏醒及言语、肢体功能恢复有更好疗效.  相似文献   
126.
Plasma treatment on a zirconia surface prevents bacterial contamination and maintains osteoblast activity. To assess the degree of adhesion of Porphyromonas gingivalis on a zirconia surface after non-thermal plasma (NTP) treatment, specimens were treated with plasma for 60, 300, and 600 s, after which P. gingivalis was inoculated onto the surface and incubated for 48 h. To assess osteoblast activity after NTP treatment, osteoblasts (MC3T3-E1) were dispensed onto the specimens contaminated with P. gingivalis immediately after NTP for 60 and 120 s, followed by incubation for 48, 72, and 96 h. P. gingivalis was cultured after 60 s of NTP treatment of zirconia. The NTP and control groups showed no significant difference (p = 0.91), but adhesion was significantly increased following NTP treatment for 300 s or longer (300, 600 s groups) (p < 0.05). After NTP treatment of P. gingivalis-contaminated zirconia, osteoblast activity significantly increased at 72 and 96 h (I60 and I120 s group) in the groups treated with plasma (p < 0.017). Application of NTP to dental zirconia implants for 60 s not only inhibits the proliferation of P. gingivalis, which causes peri-implantitis but also increases osseointegration on zirconia surfaces contaminated with P. gingivalis.  相似文献   
127.
目的研究井冈霉素产生菌吸水链霉菌井冈变种的原生质体制备与再生的最佳条件。方法使用溶菌酶水解菌体细胞壁法,分别考察影响吸水链霉菌井冈变种原生质体的制备与再生的各种因素。结果在R2YE液体培养基中,一级菌丝体的最佳培养时间为24 h,二级菌丝体的最佳培养时间为16 h,最佳甘氨酸质量浓度为5 g.L-1,最佳溶菌酶质量浓度为2 g.L-1,最佳酶解时间为60 min,最佳再生培养基为R2YE,原生质体的再生率最高可达到15.79%。结论本实验确定了吸水链霉菌井冈变种的原生质体制备与再生的最佳条件,能够得到较高的再生率。  相似文献   
128.
The gas-phase formation of new particles less than 1 nm in size and their subsequent growth significantly alters the availability of cloud condensation nuclei (CCN, >30–50 nm), leading to impacts on cloud reflectance and the global radiative budget. However, this growth cannot be accounted for by condensation of typical species driving the initial nucleation. Here, we present evidence that nucleated iodine oxide clusters provide unique sites for the accelerated growth of organic vapors to overcome the coagulation sink. Heterogeneous reactions form low-volatility organic acids and alkylaminium salts in the particle phase, while further oligomerization of small α-dicarbonyls (e.g., glyoxal) drives the particle growth. This identified heterogeneous mechanism explains the occurrence of particle production events at organic vapor concentrations almost an order of magnitude lower than those required for growth via condensation alone. A notable fraction of iodine associated with these growing particles is recycled back into the gas phase, suggesting an effective transport mechanism for iodine to remote regions, acting as a “catalyst” for nucleation and subsequent new particle production in marine air.

Marine aerosol formation contributes significantly to the global radiative budget given the high susceptibility of marine stratiform cloud radiative properties to changes in cloud condensation nuclei (CCN) availability. Atmospheric new-particle-formation is thought to involve nucleation of sulfuric acid with water, ammonia, or amines followed by condensation/growth in the presence of organic vapors (1, 2). Unique in the marine boundary layer (MBL), new particle formation involves sequential addition of HIO3 or clustering of iodine oxides (IxOy) (3, 4). In specific source regions such as coastal zones, seaweed beds, or snowpack/pack-ice, iodine oxide nucleation can be a driving force for nucleation (57). Over Arctic waters, nonetheless, one study finds insufficient iodic acid vapors to grow nucleated particles to CCN sizes (8), whereas another study finds that both nucleation and growth are almost exclusively driven by iodic acid (9). Over the open ocean, the supply of iodine oxides has been thought to be limited; however, recent measurements suggest that significant reactive iodine chemistry can occur in these regions (10). Moreover, observational evidence exists for open ocean particle formation and growth, especially when oceanic productivity is high (11, 12). An increase in atmospheric iodine levels in the North Atlantic since the mid-20th century has been shown to be driven by growth of anthropogenic ozone and enhanced subice phytoplankton production (13). While the reported IO concentration (0.4–3.1 ppt) in the remote MBL (10, 14, 15) is likely sufficient for formation of prenucleation clusters (∼1 nm), growth of these initial clusters requires the presence of other condensable vapors (16). Since preexisting aerosol particles act as a strong sink for the nucleated clusters, thus inhibiting atmospheric aerosol and CCN formation (17, 18), this early growth phase is essential for their survival. Whereas sulfuric acid vapor is also involved in nucleation, its level in remote open ocean is generally too low (105 molecules cm−3) to support subsequent particle growth, leaving organic vapors as the most plausible alternative for particle growth.In the marine atmosphere, condensing organics must originate from the oxidation of marine volatile organic compounds (VOCs), which predominantly comprise C1–C5 VOCs (e.g., isoprene) released from phytoplankton. Principal high volatility oxidation products consist of intermediate oxidized organics (IOOs), such as polyhydric alcohols (e.g., tetrols) or polyfunctional carbonyls (e.g., glyoxal) (1922). Nonetheless, growth of available prenucleation clusters/nanometer particles requires condensing organic molecules of low effective volatilities (i.e., saturation mass concentration, C* < ∼10−3 μg m−3); otherwise, preferential condensation of the organic mass to larger-diameter particles would occur (23, 24). Formation of such extremely low-volatility organic compounds (ELVOCs) from gas-phase reaction is well established for monoterpene oxidation products (25, 26).A potential pathway for formation of low-volatility organics could also result from particle-phase chemical reactions induced by iodine oxides in the early stages of marine particle formation. When the underlying chemistry is sufficiently fast, kinetic condensation occurs, resulting in particles with diameters smaller than about 50 nm growing at the same rate (e.g., nm h−1) (24). If, however, particle-phase chemistry is preferentially favored in the smallest particles (i.e., stemming from the higher relative concentration of iodine oxides in freshly formed marine particles), growth of the nucleated particles could proceed more rapidly, as compared to that in which gas-phase chemistry is the source of the low-volatility compounds (23).In this paper, we present experimental results from field measurements as well as laboratory studies of nanometer particle growth and derive a plausible chemical mechanism from the results that can explain the observations of ultrafine particle growth in the marine atmosphere. The results suggest that both iodine and condensed organics contribute to particle growth from a nascent nucleation mode into an ultrafine particle mode. Moreover, laboratory studies of the growth of seed iodine oxide particles (IOP) via heterogeneous reactions with organic vapors suggest a hitherto unrecognized mechanism that fast-tracks the growth of nucleation mode clusters into survivable aerosol particles. In this process, a notable fraction of the iodine associated with these growing particles is recycled back to the gas phase, suggesting a transport mechanism for iodine to remote regions.  相似文献   
129.
目的 观察改良复合式小梁切除术治疗青光眼的临床疗效。方法 随机选择26例(36眼)青光眼患者施行复合式小梁切除术(观察组);随机对照组32例(38眼)行单纯小梁切除术,分析比较两组术后眼压、滤过泡及前房深度。结果 术后第1天浅前房发生率观察组为2.8%,明显低于对照组21.1%(P〈0.05)。随访一年,观察组功能性滤过泡占88.9%,较对照组功能性滤过泡65.8%为多(P〈0.05);以不用降眼压药物眼压控制在21mmHg(1mmHg=0.133kPa)以下为手术成功标准,观察组手术成功率为94.4%,较对照组71.1%为高(P〈0.05)。结论 改良复合式小梁切除术提高了手术成功率,可有效地控制滤过量而减少术后浅前房的发生。  相似文献   
130.
Inhibition of homodimerization of Toll-like receptor 4 by curcumin   总被引:6,自引:0,他引:6  
Toll-like receptors play a key role in sensing microbial components and inducing innate immune responses. Ligand-induced dimerization of TLR4 is required for the activation of downstream signaling pathways. Thus, the receptor dimerization may be one of the first lines of regulation in activating TLR-mediated signaling pathways and induction of subsequent immune responses. LPS induces the activation of NF-kappaB and IRF3 through MyD88- or TRIF-dependent pathways. Curcumin, a polyphenol found in the plant Curcuma longa, has been shown to suppress the activation of NF-kappaB induced by various pro-inflammatory stimuli by inhibiting IKKbeta kinase activity in MyD88-dependent pathway. Curcumin also inhibited LPS-induced IRF3 activation. These results imply that curcumin inhibits both MyD88- and TRIF-dependent pathways in LPS-induced TLR4 signaling. However, in TRIF-dependent pathway, curcumin did not inhibit IRF3 activation induced by overexpression of TRIF in 293T cells. These results suggest that TLR4 receptor complex is the molecular target of curcumin in addition to IKKbeta. Here, we report biochemical evidence that phytochemicals (curcumin and sesquiterpene lactone) inhibit both ligand-induced and ligand-independent dimerization of TLR4. Furthermore, these results demonstrate that small molecules with non-microbial origin can directly inhibit TLRs-mediated signaling pathways at the receptor level. These results imply that the activation of TLRs and subsequent immune/inflammatory responses induced by endogenous molecules or chronic infection can be modulated by certain dietary phytochemicals we consume daily.  相似文献   
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