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SSAO酶在脂肪细胞中的含量较多,位于细胞膜上的SSAO酶的活性和其蛋白质的免疫反应性都是最大的.对于体内葡萄糖的运输和葡萄糖转运蛋白的转运,此酶起到了一定的促进作用,当它与底物在膜上反应后会引起信号传导刺激细胞内葡萄糖转运蛋白(GLUT4)从内部囊泡转移到细胞表面程,从而促进葡萄糖的运输和细胞对葡萄糖的吸收.如果有SSAO酶抑制剂存在,如氨基脲,二溴乙胺等,这种对GLUT4转运的促进作用就会被削弱.本研究的目的在于建立一种新的定量方法-竞争ELISA法来测试脂肪细胞膜上GLUT4的含量,从而确定SSAO酶抑制剂对GLUT4转运的作用.实验结果说明当SSAO酶抑制剂和脂肪细胞预温育一段时间后,质膜上GLUT4的含量发生下降,钒盐使得这种下降的程度加大,证明GLUT4由细胞内囊泡向细胞质膜转运的易位过程受到了抑制.此种竞争性ELISA的测试方法优点在于只需要少量的细胞膜样品就可以确定GLUT4的含量,灵敏度较高. 相似文献
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Semicarbazide-Sensitive Amine Oxidase对血糖调节作用研究 总被引:1,自引:0,他引:1
Semicarbazide-Sensitive Amine Oxidase (SSAO)是一类在人体内广泛分布但生理功能尚不清楚的酶.本研究中我们首次在动物模型上发现了SSAO活性对大鼠血糖的影响.通过使用SSAO的高选择性抑制剂MDL-72974A以及它的内源性底物甲胺等对动物进行处理,研究血糖与SSAO活性的关系.SSAO活性用同位素标记法以14C-苯甲胺为底物进行测定,血糖则采用己糖激酶法测定.此外我们还测定了尿甲醛排泄以考察SSAO催化脱氨反应是否发生.实验结果显示,抑制SSAO活性可以导致动物血糖升高,并且SSAO底物甲胺可以降低糖尿病鼠血糖.这些结果表明SSAO可能在血糖调节方面有某种作用,进一步研究将对发展糖尿病治疗策略有重要意义. 相似文献
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肌酸是一种普遍流行的能量增强剂。尽管短期服用肌酸不会对健康产生不良影响,但长期使用肌酸的安全性逐渐为人们所关注。本实验以研究肌酸的副面效应为出发点,建立大鼠模型,通过检测大鼠血清中SSAO活性以及各项生理指标来验证肌酸是否具有毒性伤害。结果表明外源性肌酸的摄入,会引起大鼠体内血清SSAO活性的升高,肌酸与X共同作用,可明显降低血清中SSAO活性。且长期服用肌酸可能会引发肾功能的轻微损伤以及肝脏的炎症。313swiss细胞与不同浓度肌酸共培养后,细胞存活率明显降低。初步证明了长期大量服用肌酸会造成一定的毒性伤害,对口服肌酸的长期毒性给予了肯定的评价。 相似文献
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SSAO酶在脂肪细胞中的含量较多,位于细胞膜上的SSAO酶的活性和其蛋白质的免疫反应性都是最大的。对于体内葡萄糖的运输和葡萄糖转运蛋白的转运,此酶起到了一定的促进作用,当它与底物在膜上反应后会引起信号传导刺激细胞内葡萄糖转运蛋白(GLUT4)从内部囊泡转移到细胞表面程,从而促进葡萄糖的运输和细胞对葡萄糖的吸收。如果有SSAO酶抑制剂存在,如氨基脲,二溴乙胺等,这种对GLUT4转运的促进作用就会被削弱。本研究的目的在于建立一种新的定量方法-竞争ELISA法来测试脂肪细胞膜上GLUT4的含量,从而确定SSAO酶抑制剂对GLUT4转运的作用。实验结果说明当SSAO酶抑制剂和脂肪细胞预温育一段时间后,质膜上GLUT4的含量发生下降,钒盐使得这种下降的程度加大,证明GLUT4由细胞内囊泡向细胞质膜转运的易位过程受到了抑制。此种竞争性ELISA的测试方法优点在于只需要少量的细胞膜样品就可以确定GLUT4的含量,灵敏度较高。 相似文献
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研究了石油焦(生焦和煅后焦)样品压片法制样的条件,确定了压片法使用的粘结剂,制定了利用X射线荧光光谱仪测定石油焦中微量和痕量元素的方法。选用PC和GPW系列标准样品,采用仪器软件SuperQ中提供的飞利浦模式的经验系数(Classic)和铑(Rh)靶康普顿散射线内标法校正元素间的谱线重叠干扰和基体效应,通过充分研磨样品消除颗粒效应。使用Magix(PW2403)X射线荧光光谱仪对样品中的Na、Mg、Al、Si、P、S、Cl、K、Ca、Ba、Ti、V、Cr、Mn、Fe、Ni、Cu、和Zn共18个元素进行测定,11次测定的相对标准偏差小于10%,用PC和GPW标准样品验证,测量结果与标准值的误差在化学分析允许差范围内。 相似文献
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硫化橡胶拉伸弹性模量测定方法的研究 总被引:1,自引:0,他引:1
该文研究了一种硫化橡胶拉伸弹性模量测定方法,测定方法是采用电脑系统拉力试验机作为测量装置,硫化橡胶受到拉伸时电脑将显示拉力、应力与应变等数据和图表,应力与应变之比即为橡胶的弹性模量,此方法方便、快捷、效率高。 相似文献
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分光光度法测定婴幼儿食品和乳品中左旋肉碱的方法探讨 总被引:1,自引:0,他引:1
左旋肉碱是婴幼儿乳粉中必需的营养成分添加剂之一.本研究利用产品中游离的左旋肉碱可与乙酰辅酶A反应生成乙酰肉碱和游离的辅酶A的原理,通过分光光度法检测游离的辅酶A与显色液反应生成黄色物质的量,间接求出试样中左旋肉碱含量.实验结果表明:乙酰辅酶A溶液的加入量为80μL,肉碱乙酰转移酶溶液的加入量为100μL,反应时间5分钟时,能够达到准确、经济、快捷的检测要求. 相似文献
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A calorimetric method to determine water activity covering the full range of the water activity scale is presented. A dry stream of nitrogen gas is passed either over the solution whose activity should be determined or left dry before it is saturated by bubbling through water in an isothermal calorimeter. The unknown activity is in principle determined by comparing the thermal power of vaporization related to the gas stream with unknown activity to that with zero activity. Except for three minor corrections (for pressure drop, non-perfect humidification, and evaporative cooling) the unknown water activity is calculated solely based on the water activity end-points zero and unity. Thus, there is no need for calibration with references with known water activities. The method has been evaluated at 30 °C by measuring the water activity of seven aqueous sodium chloride solutions ranging from 0.1 mol kg(-1) to 3 mol kg(-1) and seven saturated aqueous salt solutions (LiCl, MgCl(2), NaBr, NaCl, KCl, KNO(3), and K(2)SO(4)) with known water activities. The performance of the method was adequate over the complete water activity scale. At high water activities the performance was excellent, which is encouraging as many other methods used for water activity determination have limited performance at high water activities. 相似文献
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V. S. Gorchev 《Russian Engineering Research》2009,29(12):1241-1247
In the study of automated lines, a method is proposed for determining the constants of integration in the case of the general
solution when the productivities of different sections of the line are unequal (q
1 > q
2 or q
1 < q
2) and the particular solution when q
1 = q
2. This method provides the basis for the solution of all problems regarding 2 × 1 automatic lines with deterministic processes. 相似文献
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3-Aminopropyl) triethoxysilane (APTES) is commonly used to functionalize glass substrates because it can form an amine-reactive film that is tightly attached to the surface. In this study, we investigated the morphology and chemical reactivity of APTES films prepared on glass substrates using common deposition techniques. Films were prepared using concentrated vapor-phase deposition, dilute vapor-phase deposition, anhydrous organic-phase deposition and aqueous-phase deposition. All films were annealed, or cured, at 150 degrees C. The morphology of the films was quantified by fluorescence and by atomic force microscopy (AFM). The optical equivalent of the AFM images was computed and then used to directly compare optical and AFM images. Reactive amine density was determined by a picric acid assay and by a method that employed N-succinimidyl 3-[2-pyridyldithio]-propionamido (SPDP) cross-linked rhodamine. Fluorescence and AFM images showed that silane films prepared from dilute vapor-phase and aqueous-phase deposition were more uniform and had fewer domains than those deposited by the other methods. The ratio of picric acid-accessible amino groups to SPDP cross-linked rhodamine-accessible groups varied with the preparation method, suggesting reactant size-dependent difference in amine accessibility. We found a larger number of accessible amino groups on films prepared by vapor-phase deposition than on those prepared from solution deposition. The dilute vapor-phase deposition technique produced relatively few domains, and it should be a good choice for bioconjugation applications. There were appreciable differences in the films produced by each method. We suggest that these differences originate from differences in film rearrangement during annealing. 相似文献
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原子时标国家计量基准 UTC(NIM)由中国计量科学研究院维护和保持,溯源至协调世界时(UTC),是统一全国时间频
率量值的最高依据。 随着信息技术的不断发展,时间戳服务被广泛应用于司法、医疗、金融、电子商务、知识产权等领域。 根据
我国在贸易结算、医疗等领域对法制计量的需求,时间戳机构(TSA)提供的时间应溯源至 UTC(NIM)以实现国内统一和国际互
认。 本文提出使用一种校准器对 TSA 提供的时间进行远程和本地评估。 实验结果表明,在局域网进行本地校准时,TSA 与 UTC
(NIM)时间偏差的不确定度(k = 2)小于 2 ms;在广域网环境下,即使校准器与 TSA 之间相距超过 1 000 km,TSA 与 UTC(NIM)
时间偏差的不确定度(k = 2)小于 713 ms。 相似文献