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111.
A sensitive chronocoulometric aptasensor for the detection of thrombin has been developed based on gold nanoparticle amplification. The functional gold nanoparticles, loaded with link DNA (LDNA) and report DNA (RDNA), were immobilized on an electrode by thrombin aptamers performing as a recognition element and capture probe. LDNA was complementary to the thrombin aptamers and RDNA was noncomplementary, but could combine with [Ru(NH3)6]3+ (RuHex) cations. Electrochemical signals obtained by RuHex that bound quantitatively to the negatively charged phosphate backbone of DNA via electrostatic interactions were measured by chronocoulometry. In the presence of thrombin, the combination of thrombin and thrombin aptamers and the release of the functional gold nanoparticles could induce a significant decrease in chronocoulometric signal. The incorporation of gold nanoparticles in the chronocoulometric aptasensor significantly enhanced the sensitivity. The performance of the aptasensor was further increased by the optimization of the surface density of aptamers. Under optimum conditions, the chronocoulometric aptasensor exhibited a wide linear response range of 0.1–18.5 nM with a detection limit of 30 pM. The results demonstrated that this nanoparticle-based amplification strategy offers a simple and effective approach to detect thrombin. 相似文献
112.
Jiao Deng Jiejie Li Liaoliao Li Chenzhuo Feng Lize Xiong Zhiyi Zuo 《Transgenic research》2013,22(4):757-766
Parasympathetic tone is a dominant neural regulator for basal heart rate. Glutamate transporters (EAAT) via their glutamate uptake functions regulate glutamate neurotransmission in the central nervous system. We showed that EAAT type 3 (EAAT3) knockout mice had a slower heart rate than wild-type mice when they were anesthetized. We design this study to determine whether non-anesthetized EAAT3 knockout mice have a slower heart rate and, if so, what may be the mechanism for this effect. Young adult EAAT3 knockout mice had slower heart rates than those of their littermate wild-type mice no matter whether they were awake or anesthetized. This difference was abolished by atropine, a parasympatholytic drug. Carbamylcholine chloride, a parasympathomimetic drug, equally effectively reduced the heart rates of wild-type and EAAT3 knockout mice. Positive immunostaining for EAAT3 was found in the area of nuclei deriving fibers for vagus nerve. There was no positive staining for the EAATs in the sinoatrial node. These results suggest that EAAT3 knockout mice have a slower heart rate at rest. This effect may be caused by an increased parasympathetic tone possibly due to increased glutamate neurotransmission in the central nervous system. These findings indicate that regulation of heart rate, a vital sign, is one of the EAAT biological functions. 相似文献
113.
Meng Zhang Liang Dong Zhubing Shi Shi Jiao Zhen Zhang Wenqing Zhang Guoguang Liu Cuicui Chen Miao Feng Qian Hao Wenjia Wang Mengxin Yin Yun Zhao Lei Zhang Zhaocai Zhou 《Structure (London, England : 1993)》2013,21(4):680-688
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114.
Gliomas can diffuse into the normal brain and this invasion of glioma cells involves modification of receptor-mediated adhesive properties of tumor cells, degradation and remodeling of extracellular matrix by tumor-secreted metalloproteinase (MMPs) such as MMP-2, consequently creating an intercellular space for invasion of glioma cells. BmK CT, one of the key toxins in scorpion Buthus martensii Karsch venom, is a novel blocker of the chloride ion channel and MMP-2. In this report, a recombinant plasmid pEGFP-N1-BmK CT was constructed and characterized by in vitro studies. The results showed that pEGFP-N1 mediated BmK CT expression displayed a high activity in suppressing cell migration via MMP-2. The potential therapeutic effect of pEGFP-N1 mediated BmK CT against rat glioma C6 cells was assessed and its potential mechanism was elucidated. It represented an approach for developing a novel therapeutic agent—recombinant plasmid pEGFP-N1-BmK CT as an efficient and powerful adjuvant. 相似文献
115.
目的:探讨280例胃食管反流病(GERD)的分布特点及危险因素。方法:对临床诊断和胃镜确诊的280例GERD患者进行临床和风险因子相关性分析。结果:不论汉族还是维族,男性患者比例均明显高于女性;汉族患者高发年龄段早于维族患者(z=-2.939,P=0.003,);汉族和维族患者占反流性食管炎和Barrett食管比例分别为42.4%、81_3%及56.5%、18.8%,其中汉族患者Barrett食管比例较高(X2=14.358,P=0.000);肥胖、习惯性便秘、重体力活动者、饮食习惯不良在维族患者中的比例较高(P〈0.001)。结论:GERD与性别、年龄密切相关,男性多于女性,汉族患者发病年龄高峰旱于维族患者;汉族患者Barrett食管发生比例高于维族患者;肥胖、习惯性便秘、重体力活动、饮食习惯不良可能是GERD尤其是维族人群GERD的危险因素。 相似文献
116.
CongXin Dai Feng Cai Kuo Chu Hwang YongMao Zhou ZiZhu Zhang XiaoHai Liu SiHai Ma YaKun Yang Yong Yao Ming Feng XinJie Bao GuiLin Li JunJi Wei YongHui Jiao ZhenQing Wei WenBin Ma RenZhi Wang 《中国科学:生命科学英文版》2013,56(2):163-173
Invasive nonfunctional pituitary adenomas (NFPAs) are difficult to completely resect and often develop tumor recurrence after initial surgery. Currently, no medications are clinically effective in the control of NFPA. Although radiation therapy and radiosurgery are useful to prevent tumor regrowth, they are frequently withheld because of severe complications. Boron neutron capture therapy (BNCT) is a binary radiotherapy that selectively and maximally damages tumor cells without harming the surrounding normal tissue. Folate receptor (FR)-targeted boron-10 containing carbon nanoparticles is a novel boron delivery agent that can be selectively taken up by FR-expressing cells via FR-mediated endocytosis. In this study, FR-targeted boron-10 containing carbon nanoparticles were selectively taken up by NFPAs cells expressing FR but not other types of non-FR expressing pituitary adenomas. After incubation with boron-10 containing carbon nanoparticles and following irradiation with thermal neutrons, the cell viability of NFPAs was significantly decreased, while apoptotic cells were simultaneously increased. However, cells administered the same dose of FR-targeted boron-10 containing carbon nanoparticles without neutron irradiation or received the same neutron irradiation alone did not show significant decrease in cell viability or increase in apoptotic cells. The expression of Bcl-2 was down-regulated and the expression of Bax was up-regulated in NFPAs after treatment with FR-mediated BNCT. In conclusion, FR-targeted boron-10 containing carbon nanoparticles may be an ideal delivery system of boron to NFPAs cells for BNCT. Furthermore, our study also provides a novel insight into therapeutic strategies for invasive NFPA refractory to conventional therapy, while exploring these new applications of BNCT for tumors, especially benign tumors. 相似文献
117.
A validated HPLC-DAD-ESI-MSn method for the analysis of non-anthocyanin flavonoids was applied to nine different tissues of twelve lotus genotypes of Nelumbo nucifera and N. lutea, together with an optimized anthocyanin extraction and separation protocol for lotus petals. A total of five anthocyanins and twenty non-anthocyanin flavonoids was identified and quantified. Flavonoid contents and compositions varied with cultivar and tissue and were used as a basis to divide tissues into three groups characterized by kaempferol and quercetin derivatives. Influences on flower petal coloration were investigated by principal components analyses. High contents of kaempferol glycosides were detected in the petals of N. nucifera while high quercetin glycoside concentrations occurred in N. lutea. Based on these results, biosynthetic pathways leading to specific compounds in lotus tissues are deduced through metabolomic analysis of different genotypes and tissues and correlations among flavonoid compounds. 相似文献
118.
Nicholas S. Kirkby Anne K. Zaiss Paula Urquhart Jing Jiao Philip J. Austin Malak Al-Yamani Martina H. Lundberg Louise S. MacKenzie Timothy D. Warner Anna Nicolaou Harvey R. Herschman Jane A. Mitchell 《PloS one》2013,8(7)
There are two schools of thought regarding the cyclooxygenase (COX) isoform
active in the vasculature. Using urinary prostacyclin markers some groups have
proposed that vascular COX-2 drives prostacyclin release. In contrast, we and
others have found that COX-1, not COX-2, is responsible for vascular
prostacyclin production. Our experiments have relied on immunoassays to detect
the prostacyclin breakdown product, 6-keto-PGF1α and antibodies to
detect COX-2 protein. Whilst these are standard approaches, used by many
laboratories, antibody-based techniques are inherently indirect and have been
criticized as limiting the conclusions that can be drawn. To address this
question, we measured production of prostanoids, including
6-keto-PGF1α, by isolated vessels and in the circulation
in vivo using liquid chromatography tandem mass
spectrometry and found values essentially identical to those obtained by
immunoassay. In addition, we determined expression from the
Cox2 gene using a knockin reporter mouse in which
luciferase activity reflects Cox2 gene expression. Using this
we confirm the aorta to be essentially devoid of Cox2 driven
expression. In contrast, thymus, renal medulla, and regions of the brain and gut
expressed substantial levels of luciferase activity, which correlated well with
COX-2-dependent prostanoid production. These data are consistent with the
conclusion that COX-1 drives vascular prostacyclin release and puts the sparse
expression of Cox2 in the vasculature in the context of the
rest of the body. In doing so, we have identified the thymus, gut, brain and
other tissues as target organs for consideration in developing a new
understanding of how COX-2 protects the cardiovascular system. 相似文献
119.
Chunmei Zhang Chao Yang Ruifei Wang Yang Jiao Khamal Kwesi Ampah Xiaoguang Wang Xianlu Zeng 《PloS one》2013,8(6)
Integrins are heterodimeric transmembrane receptors that physically link the extracellular matrix (ECM) to the intracellular actin cytoskeleton, and are also signaling molecules that transduce signals bi-directionally across the plasma membrane. Integrin regulation is essential for tumor cell migration in response to growth factors. c-Abl kinase is a nonreceptor tyrosine kinase and is critical for signaling transduction from various receptors. Here we show that c-Abl kinase is involved in A375 cell migration mediated by αvβ3 integrin in response to PDGF stimulation. c-Abl kinase colocalizes with αvβ3 integrin dynamically and affects αvβ3 integrin affinity by regulating its cluster. The interaction between c-Abl kinase and αvβ3 integrin was dependent on the activity of c-Abl kinase induced by PDGF stimulation, but was not dependent on the binding of αvβ3 integrin with its ligands, suggesting that c-Abl kinase is not involved in the outside-in signaling of αvβ3 integrin. Talin head domain was required for the interaction between c-Abl kinase and αvβ3 integrin, and the SH3 domain of c-Abl kinase was involved in its interaction with talin and αvβ3 integrin. Taken together, we have uncovered a novel and critical role of c-Abl kinase in αvβ3 integrin mediated melanoma cell migration. 相似文献
120.
Guang-Zhong Jiao Xin-Yan Cao Wei Cui Hua-Yu Lian Yi-Long Miao Xiu-Fen Wu Dong Han Jing-He Tan 《PloS one》2013,8(3)
Although oocytes from prepubertal animals are found less competent than oocytes from adults, the underlying mechanisms are poorly understood. Using the mouse oocyte model, this paper has tested the hypothesis that the developmental potential of prepubertal oocytes is compromised due mainly to their impaired potential for glutathione synthesis. Oocytes from prepubertal and adult mice, primed with or without eCG, were matured in vitro and assessed for glutathione synthesis potential, oxidative stress, Ca2+ reserves, fertilization and in vitro development potential. In unprimed mice, abilities for glutathione synthesis, activation, male pronuclear formation, blastocyst formation, cortical granule migration and polyspermic block were all compromised significantly in prepubertal compared to adult oocytes. Cysteamine and cystine supplementation to maturation medium significantly promoted oocyte glutathione synthesis and blastocyst development but difference due to maternal age remained. Whereas reactive oxygen species (ROS) levels increased, Ca2+ storage decreased significantly in prepubertal oocytes. Levels of both catalytic and modifier subunits of the γ-glutamylcysteine ligase were significantly lower in prepubertal than in adult oocytes. Maternal eCG priming improved all the parameters and eliminated the age difference. Together, the results have confirmed our hypothesis by showing that prepubertal oocytes have a decreased ability to synthesize glutathione leading to an impaired potential to reduce ROS and to form male pronuclei and blastocysts. The resulting oxidative stress decreases the intracellular Ca2+ store resulting in impaired activation at fertilization, and damages the microfilament network, which affects cortical granule redistribution leading to polyspermy. 相似文献