人凝血因子7a(FVIIa)是外源性凝血途径的核心因子,检测参与凝血过程的FVIIa及针对FVIIa开发安全有效和经济的凝血剂和抗凝血剂是具有重要的意义。本研究基于指数富集配体系统进化技术(Systematic evolution of ligands by exponential e...人凝血因子7a(FVIIa)是外源性凝血途径的核心因子,检测参与凝血过程的FVIIa及针对FVIIa开发安全有效和经济的凝血剂和抗凝血剂是具有重要的意义。本研究基于指数富集配体系统进化技术(Systematic evolution of ligands by exponential enrichment,SELEX),采用酸纤维素膜法,通过11轮筛选成功分离出FVIIa的DNA适配体,并模拟了其二级结构。此适配体与FVIIa蛋白结合的表观解离常数为102nmol/L。同时,基于所获得的高亲和力适配体,建立了基于适配体的荧光检测方法。本方法简单高效,对FVIIa蛋白的定量检测范围达到30~80nmol/L,为人凝血因子7a的检测提供了一条新途径。非变性聚丙烯酰胺凝胶电泳和适配体的荧光检测方法结果表明,此适配体具有良好的选择性。展开更多
The interactions of antibiotic with living cells were studied by lectin conjugated gold nanoparticles（GNPs） based colorimetric assay. Because of the high affinity of lectin for saccharides, the lectin conjugated GNP...The interactions of antibiotic with living cells were studied by lectin conjugated gold nanoparticles（GNPs） based colorimetric assay. Because of the high affinity of lectin for saccharides, the lectin conjugated GNPs are able to employ as indicators for monitoring the antibiotic induced changes of glycosyl complexes. The interactions of a well known antibiotic, tunicamycin, with two different cell lines, HeLa and SHG-44, were selected to establish this assay. In the presence of tunicamycin, the dose- and time-dependence on the decreasing of binding affinity of lectin conjugated GNPs with living cells were demonstrated by conventional microscopic and UV-Vis spectroscopic studies. The experimental result demonstrates that our approach can be used to identify antibiotic induced expression difference of glycosyl complexes on different cellular surfaces and determine drug activity quantitatively. For further confirming the capability of the GNP-based assay, the system was also studied by confocal laser scanning microscopy（CLSM） and classic flow cytometry（FCM） assay, and satisfactory results were obtained.展开更多
A general functionalization strategy was reported,which enables one to conjugate saccharide（SA） on gold nanoparticle（GNP） surface without affecting SA properties.First,disulfide phenylboronic acid（Bor） functiona...A general functionalization strategy was reported,which enables one to conjugate saccharide（SA） on gold nanoparticle（GNP） surface without affecting SA properties.First,disulfide phenylboronic acid（Bor） functionalized GNPs（Bor@GNPs） were synthesized by the reaction of citrate stabilized GNPs of 13 nm in diameter with the mixture of Bor and pentapeptide（Cys-Ala-Leu-Asn-Asn,CALNN）.Subsequently,the SA-GNP conjugates（SA@GNPs） were prepared by coupling SA to the GNP surface via the reaction of phenylboronic acid（PBA） with the cis-diol configuration in SA.The interactions of three SA@GNPs with three lectins have been analyzed by UV-visible spectroscopic and transmission electronic microscopic（TEM） techniques,respectively.The experimental results demonstrate that SA@GNPs can efficiently bind to lectins and show a great promise as optical probes for monitoring specific affinities of lectins for SA,and detecting lectins with high sensitivity.展开更多
Background Multi-slice CT liver perfusion has been widely used in experimental studies of hemodynamic changes in liver lesions, and is usually performed as an adjunct to a conventional CT examination because of its hi...Background Multi-slice CT liver perfusion has been widely used in experimental studies of hemodynamic changes in liver lesions, and is usually performed as an adjunct to a conventional CT examination because of its high temporal and spatial resolution, simple protocol, good reproducibility, and ability to measure hemodynamic changes of liver tissues at the capillary level. Experimental rat models, especially those of induced liver cancer, are often used in studies of hemodynamic changes in liver cancer. Carcinogenesis in rats has a similar pathological progression and characteristics resembling those in human liver cancer; as a result, rat models are often used as ideal animal models in the study of human liver cancer. However, liver perfusion imaging in rats is difficult to perform, because rats＇ livers are so small that different concentrations, flow rates, and dose of contrast agents during the CT perfusion scanning can influence the quality of liver perfusion images in rats. The purpose of this study, therefore, was to investigate the optimal scan protocol for the imaging of hepatic perfusion using a deconvolution mathematical method in rats by comparing the results of rats in different injection conditions of the contrast agent, including concentration, rate and time. Methods Plain CT scan conditions in eighty 2-month-old male Wistar rats were 5.0 mm slice thickness, 5.0 mm interval, 1.0 pitch, 120 kV tube voltage, 60 mA tube current, 512x512 matrix, and FOV 9.6 cm. Perfusion scanning was carried out with different concentrations of diatrizoate （19%, 38%, 57%, and 76%）, different injection rates （0.3 and 0.5 ml/s）, and different injection times （1, 2-3, 4-5, and 6 seconds）. The above conditions were randomly matched and adjusted to determine the best perfusion scan protocol. Three-phase contrast-enhanced scanning was performed after CT perfusion. Histological examination of the liver tissues with hematoxylin and eosin stains was done after CT scanning. Results When the concentration of the contrast agent was 19% or 38%, no pseudo-color map was created. The viscosity increased when the concentration of the contrast agent was 76%; so it is difficult to inject the contrast agent at such a high concentration. Also no pseudo-color map was generated when the injection time was short （1, 2-3, and 4-5 seconds） or the injection rate was low （0.3 ml/s）. The best perfusion images and perfusion parameters were obtained during 50 seconds scanning. Each rat was given an injection of 57% diatrizoate at 0.5 mils via the tail vein using a high-pressure syringe for 6 seconds. The perfusion parameters included hepatic blood flow （HBF）, hepatic blood volume （HBV）, mean transit time （MTT） of the contrast agent, capillary permeability-surface area product （PS）, hepatic arterial index （HAl）, hepatic artery perfusion （HAP）, and hepatic portal perfusion （HPP）. All these parameters reflected the perfusion status of liver parenchyma in normal rats. Three phases of enhancement were modified according to the time-density curves （TDCs） of the perfusion imaging： hepatic arterial phase （7 seconds）, hepatic portal venous phase （15 seconds）, and a delayed phase （23-31 seconds）. On examination by microscopy, the liver tissues were pathologically normal. Conclusions The appropriate protocol with multi-slice spiral CT liver perfusion reflected normal liver hemodynamics in rats. This study laid a solid foundation for further investigation of the physiological characteristics of liver cancer in a rat model, and was an important supplement to and reference for conventional contrast-enhanced CT scans.展开更多
文摘人凝血因子7a(FVIIa)是外源性凝血途径的核心因子,检测参与凝血过程的FVIIa及针对FVIIa开发安全有效和经济的凝血剂和抗凝血剂是具有重要的意义。本研究基于指数富集配体系统进化技术(Systematic evolution of ligands by exponential enrichment,SELEX),采用酸纤维素膜法,通过11轮筛选成功分离出FVIIa的DNA适配体,并模拟了其二级结构。此适配体与FVIIa蛋白结合的表观解离常数为102nmol/L。同时,基于所获得的高亲和力适配体,建立了基于适配体的荧光检测方法。本方法简单高效,对FVIIa蛋白的定量检测范围达到30~80nmol/L,为人凝血因子7a的检测提供了一条新途径。非变性聚丙烯酰胺凝胶电泳和适配体的荧光检测方法结果表明,此适配体具有良好的选择性。
基金Supported by the National Natural Science Foundation of China(No.20875087)the Fund of Chinese Academy of Sciences (No.KJCX2-YW-H11)
文摘The interactions of antibiotic with living cells were studied by lectin conjugated gold nanoparticles（GNPs） based colorimetric assay. Because of the high affinity of lectin for saccharides, the lectin conjugated GNPs are able to employ as indicators for monitoring the antibiotic induced changes of glycosyl complexes. The interactions of a well known antibiotic, tunicamycin, with two different cell lines, HeLa and SHG-44, were selected to establish this assay. In the presence of tunicamycin, the dose- and time-dependence on the decreasing of binding affinity of lectin conjugated GNPs with living cells were demonstrated by conventional microscopic and UV-Vis spectroscopic studies. The experimental result demonstrates that our approach can be used to identify antibiotic induced expression difference of glycosyl complexes on different cellular surfaces and determine drug activity quantitatively. For further confirming the capability of the GNP-based assay, the system was also studied by confocal laser scanning microscopy（CLSM） and classic flow cytometry（FCM） assay, and satisfactory results were obtained.
基金Supported by the National Basic Research Program of China(No.2011CB935800)the Project of the Jilin Provincial Science and Technology Department,China(No.20100701)
文摘A general functionalization strategy was reported,which enables one to conjugate saccharide（SA） on gold nanoparticle（GNP） surface without affecting SA properties.First,disulfide phenylboronic acid（Bor） functionalized GNPs（Bor@GNPs） were synthesized by the reaction of citrate stabilized GNPs of 13 nm in diameter with the mixture of Bor and pentapeptide（Cys-Ala-Leu-Asn-Asn,CALNN）.Subsequently,the SA-GNP conjugates（SA@GNPs） were prepared by coupling SA to the GNP surface via the reaction of phenylboronic acid（PBA） with the cis-diol configuration in SA.The interactions of three SA@GNPs with three lectins have been analyzed by UV-visible spectroscopic and transmission electronic microscopic（TEM） techniques,respectively.The experimental results demonstrate that SA@GNPs can efficiently bind to lectins and show a great promise as optical probes for monitoring specific affinities of lectins for SA,and detecting lectins with high sensitivity.
文摘Background Multi-slice CT liver perfusion has been widely used in experimental studies of hemodynamic changes in liver lesions, and is usually performed as an adjunct to a conventional CT examination because of its high temporal and spatial resolution, simple protocol, good reproducibility, and ability to measure hemodynamic changes of liver tissues at the capillary level. Experimental rat models, especially those of induced liver cancer, are often used in studies of hemodynamic changes in liver cancer. Carcinogenesis in rats has a similar pathological progression and characteristics resembling those in human liver cancer; as a result, rat models are often used as ideal animal models in the study of human liver cancer. However, liver perfusion imaging in rats is difficult to perform, because rats＇ livers are so small that different concentrations, flow rates, and dose of contrast agents during the CT perfusion scanning can influence the quality of liver perfusion images in rats. The purpose of this study, therefore, was to investigate the optimal scan protocol for the imaging of hepatic perfusion using a deconvolution mathematical method in rats by comparing the results of rats in different injection conditions of the contrast agent, including concentration, rate and time. Methods Plain CT scan conditions in eighty 2-month-old male Wistar rats were 5.0 mm slice thickness, 5.0 mm interval, 1.0 pitch, 120 kV tube voltage, 60 mA tube current, 512x512 matrix, and FOV 9.6 cm. Perfusion scanning was carried out with different concentrations of diatrizoate （19%, 38%, 57%, and 76%）, different injection rates （0.3 and 0.5 ml/s）, and different injection times （1, 2-3, 4-5, and 6 seconds）. The above conditions were randomly matched and adjusted to determine the best perfusion scan protocol. Three-phase contrast-enhanced scanning was performed after CT perfusion. Histological examination of the liver tissues with hematoxylin and eosin stains was done after CT scanning. Results When the concentration of the contrast agent was 19% or 38%, no pseudo-color map was created. The viscosity increased when the concentration of the contrast agent was 76%; so it is difficult to inject the contrast agent at such a high concentration. Also no pseudo-color map was generated when the injection time was short （1, 2-3, and 4-5 seconds） or the injection rate was low （0.3 ml/s）. The best perfusion images and perfusion parameters were obtained during 50 seconds scanning. Each rat was given an injection of 57% diatrizoate at 0.5 mils via the tail vein using a high-pressure syringe for 6 seconds. The perfusion parameters included hepatic blood flow （HBF）, hepatic blood volume （HBV）, mean transit time （MTT） of the contrast agent, capillary permeability-surface area product （PS）, hepatic arterial index （HAl）, hepatic artery perfusion （HAP）, and hepatic portal perfusion （HPP）. All these parameters reflected the perfusion status of liver parenchyma in normal rats. Three phases of enhancement were modified according to the time-density curves （TDCs） of the perfusion imaging： hepatic arterial phase （7 seconds）, hepatic portal venous phase （15 seconds）, and a delayed phase （23-31 seconds）. On examination by microscopy, the liver tissues were pathologically normal. Conclusions The appropriate protocol with multi-slice spiral CT liver perfusion reflected normal liver hemodynamics in rats. This study laid a solid foundation for further investigation of the physiological characteristics of liver cancer in a rat model, and was an important supplement to and reference for conventional contrast-enhanced CT scans.
