低氧亲和力血红蛋白类氧载体的制备及大鼠动脉血压响应

氧亲和力是血红蛋白氧载体非常重要的参数之一,但其高低还没有统一的认识,有一种理论认为低氧亲和力是造成高血压的原因。为了进一步研究氧亲和力与血压之间的关系,本文制备了两种低氧亲和力的血红蛋白氧载体。用高碘酸钠氧化棉子糖（高碘酸钠：棉籽糖=6：1,摩尔比）,得到氧化均一的开环棉子糖;以其作为交联剂聚合脱氧猪血红蛋白,在聚合1 h得到了低氧亲和力（P50 = 43.1 torr）主要为分子内交联的64 kDa的血红蛋白,在聚合2 4 h得到了低氧亲和力（P50 = 51.5 torr）平均分子量为600 kDa的聚合血红蛋白;分别进行大鼠50%等容量换血实验,前者显著引起血压升高而后者血压平稳,证实高血压主要和64 kDa血红蛋白有关,低氧亲和力不是造成高血压的主要原因。     

固定化血红蛋白氧载体的研究 I.聚乙烯醇包埋血红蛋白

固定化血红蛋白可以作为氧载体，从海水中提取氧气，为人类在水下活动提供氧源。以聚乙烯醇为载体材料，固定化血红蛋白，制备氧载体。研究了该氧载体的氧解离性能以及戊二醛和六磷酸肌醇对氧载体氧解离性能的影响。血红蛋白的固定量达０．６ｇ／ｇ，氧化法测得氧载体的氧解离率为５３．３％。戊二醛后交联提高了氧载体的稳定性。六磷酸肌醇使氧解离率由２４．８％提高到６０．０％。     

固定化血红蛋白氧载体的研究(Ⅱ)——氧化纤维素共价键联血红蛋白

以纤维素为载体,经高碘酸钠氧化后共价键联血红蛋白,制备氧载体.研究了氧化条件对血红蛋白固定量的影响.纤维素只有经过预氧化、碱处理和再氧化三步活化反应,才能使血红蛋白大量固定化,每克纤维素固定血红蛋白量达1.0g.氧载体稳定性好,血红蛋白不脱落.经铁氰化钾氧化,氧载体放氧效率为33.1%.     

固定化血红蛋白氧载体的研究（Ⅱ）：氧化纤维素共价键联 …

以纤维素为载体，经高碘酸钠氧化后共价键联血红蛋白，制备氧载体。研究了氧化条件对血红蛋白固定量的影响。纤维素只有经过预氧化，碱处理和再氧化三步活化反应，才能使血红蛋白大量化，每克纤维素固定血红蛋白量达１．０ｇ。氧载体稳定性好，血红蛋白不脱落。经铁氰化钾氧化，氧载体放氧效率为３３．１％。     

固定化血红蛋白氧载体的研究：Ⅰ.聚乙烯醇包埋血红蛋白

固定化血红蛋白可以作为氧载体，从海水中提取氧气，为人类在水下提供氧源。以聚乙烯醇为载体材料，固定化血红白、制备氧载体。研究了该氧载体的氧解离性能以及戊二醛和六磷酸肌醇对氧载体氧解离性能的影响。     

四乙酸铅电位滴定法测定原油中的硫醚硫

提出复合双铂片电极作参比和指示电极,在V(冰乙酸):V(甲苯):V(水)=7:2:1介质中以少量KBr作催化剂,四乙酸铅-冰乙酸溶液作滴定剂,建立了原油中硫醚硫的测定方法.试验结果表明,该方法电位滴定突跃明显,分析速度快,电极不需内外充液,直接使用,操作简单,重复性好(相对标准偏差RSD=0.32%)等特点,已应用于兰州石化常减压原油中硫醚硫含量的测定.     

MgBu_2/AlEt_2Cl为助催剂的钛催化剂上丙烯聚合动力学——Ⅰ.烷基金属浓度的影响

烯烃聚合催化剂种类繁多,改变金属离子或配位体能得到性能不同的烯烃聚合催化剂.可供选择的助催化剂主要有烷基铝,烷基氯化铝,铝氧烷和Cp_2MtMe化合物等(Mt=Ti,V,Zr,Hf).有实用价值的助催化剂只有烷基铝或烷基氯化铝.对丙烯聚合非载体钛系催化剂而言,AlEt_2Cl是较好的助催化剂,而对载体型MgCl_2/TiCl_4钛系催化剂,较好的助催化剂则是AlEt_3.如果将MgBu_2与AlEt_2Cl的混合物用     

人工氧载体研究进展

血液需求的激增和异体输血的不安全性等问题的出现,促使人们合成“血液替代品”。通过对天然氧载体(即血红蛋白)结构与性能的清晰认识,已有多种人工氧载体被成功合成,并应用于临床试验。人工氧载体可分为全氟碳化合物、血红蛋白基氧载体、合成血红素及其高分子配合物三大类。全氟碳化合物虽大部分已退出人工血液市场,但因其具有治疗作用,研究工作仍在进行。为了降低血红蛋白基氧载体的副作用,已采用多种方法对血红蛋白进行改性,如采用化学修饰、微囊包裹(HbV)、重组和仿生纳米等技术。其中,血红蛋白囊泡模拟红细胞的结构,其粒径相对较大(250nm),副作用相对较低,是目前血红蛋白基氧载体的发展趋势。人工合成血红素如栏式卟啉只溶于有机溶剂,为增加其水溶性,可使其与白蛋白、木糖醇酶和环糊精等高分子结合为配合物,经动物实验表明,这些高分子金属配合物在体内具有运送氧气功能。除主要在临床上用作血液代替品外,人工氧载体还在肿瘤治疗、器官移植和缺血/再灌注损伤的预防等方面具有重要的临床应用价值。     

原料奶、婴儿配方奶粉及酸奶中蛋白去除效果的研究

建立了毛细管电泳法分析α-乳白蛋白、β-乳球蛋白A及β-乳球蛋白B的方法,考察了不同浓度冰乙酸(HAc)及三氯乙酸(TCA)对原料奶、婴儿配方奶粉A和B及酸奶中蛋白的去除效果。结果表明,TCA去除蛋白效果优于HAc,不同样品所需TCA浓度不同:2g原料奶需3mL100g/LTCA;0.5g婴儿配方奶粉A和B分别需5mL10g/L及20g/LTCA;2g酸奶则需3mL20g/LTCA才能将蛋白完全沉淀。为原料奶、婴儿配方奶粉及酸奶等乳制品的样品前处理提供了有价值的参考。     

羧化聚丙烯载体的链结构对丙烯腈聚合的影响

研究了羧化聚丙烯载体(不饱和羧酸接枝聚丙烯)接枝链的结构对丙烯腈聚合速度的影响。在引发活性方面对聚羧酸氧钒(聚合物负载催化剂)、异丁酸氧钒(小分子同系物)和硫酸氧钒(小分子非同系物)作了对比。实验结果表明:(1)(P-COO)_2VO两羧基之间存在着协同作用;(2)大分子链效应加强了羧基的协同作用;(3)聚羧酸链的d-、1-构型、羧基间距和载体的传质效应对聚合速度均有影响;(4)在本实验条件下,引发机理与高分子载体的链结构无关。     

高效液相色谱法测定血红蛋白氧载体中残留的戊二醛

建立了一种测定血红蛋白氧载体中戊二醛残余含量的高效液相色谱方法.用10 kDa超滤膜通过离心3000 r/min×20 min将游离戊二醛从待测样品中分离;在pH 1.0时,在含有70%乙腈的体系中用2,4-二硝基苯肼在30 min内将戊二醛衍生成2,4-二硝基苯腙(n(2,4-二硝基苯肼): n(戊二醛)=60: 1),以70%乙腈为流动相,避免了衍生产物生成沉淀.用高效液相色谱法分离测定衍生物,可在20 min内完成分离,同时对衍生步骤进行了优化.本方法具有较高的灵敏度和良好的线性关系,检出限为1.0 ng,在0.1～10 mg/L范围内其线性相关系数为0.9999,重复测定6次的相对标准偏差小于3.0%,回收率为95.26%.     

游离125I与血浆蛋白的结合及其对血药浓度测定的影响

通过体内、外实验, 研究了游离125I与血浆蛋白的结合及其在三氯乙酸(TCA)沉淀后的沉淀百分率, 并与125I-RGD-Sak在SD大鼠中不同时间血药浓度的结果进行了比较. 结果表明, 游离125I能与血浆蛋白结合, 并为TCA所沉淀, 且在一定范围内, 游离125I与血浆蛋白结合后的沉淀百分率与温育时间及游离125I的活度无关. 体内、外实验中, 游离125I与血浆蛋白结合后的沉淀百分率分别为(1.26±0.14)%及(1.38±0.33)%. 沉淀物中含有吸附在沉淀物表面的游离125I, 该吸附需要用TCA沉淀2~3次才能去除. 采用125I核素示踪法进行生物类制品的药代动力学研究时, 应对游离125I的影响进行校正.     

在线化学蒸气发生-电感耦合等离子体原子发射光谱法测定废催化剂中的微量铑

使用电感耦合等离子原子发射光谱(ICP-AES)研究了贵金属铑和NaBH4在酸性水溶液中的化学蒸气发生反应的条件,并测定了有机合成催化剂中的铑。研究结果表明:在NaBH4和样品溶液流速为2mL/min、废液排放流速为6mL/min的条件下的最佳蒸气发生条件为:载气流速0.4L/min、HNO3浓度为1.0mol/L、NaBH4浓度为1.2%(m/V)。研究中获得的铑化学蒸气进样效率是常规的气动雾化进样效率的2.7倍;检出限是6.9μg/L,略优于气动雾化法;线性范围20～1500μg/L;线性相关系数是0.9986;RSD是1.6%。样品分析加标回收率分别是94%和97%。用本法测得的样品值与原子吸收法的测得值吻合很好。     

Boron Nitride Nanosheet Modified Electrode: Preparation and Application to Direct Electrochemistry of Myoglobin

An ionic liquid modified carbon paste electrode (CILE) was prepared with 1‐hexylpyridine hexafluorophosphate (HPPF₆) and used as a substrate electrode. Then hexagonal boron nitride (BN) nanosheet, myoglobin (Mb) and Nafion were fixed on the electrode surface by coating method to get a new‐style chemically modified electrode (Nafion/Mb/BN/CILE). The morphology and crystal phase of BN nanosheet were characterized by SEM, TEM and XRD. UV‐Vis and FT‐IR results showed that Mb retained its original conformation in the composite modified film. In phosphate buffer solutions (PBS) with pH 3.0, cyclic voltammetry (CV) was performed to investigate the direct electrochemical behaviour of Mb. A pair of quasi‐reversible redox reaction peaks was obtained on the CV curve, proving that BN nanosheet had good biocompatibility and could accelerate electron transfer between Mb and electrode surface. Electrocatalytic reduction of trichloroacetic acid (TCA) was investigated, which was further applied to TCA detection. The catalytic reduction peak current at ?0.355 V depended linearly on the TCA concentration in the range of 0.2～30.0 mmol/L with the equation of Ipc (μA)=6.340 C (mmol/L)+0.305 (r=0.998), and the detection limit was 0.05 mmol/L (3 σ).     

硼-姜黄素络合物的高效液相色谱研究及应用

本文研究了在非水体系中硼与质子化的姜黄素形成的络合物以无水甲醇为溶剂,在C18色谱柱上用甲醇-水(80:20 V/V)作流动相(1.00mL/min)分离并检测.硼的校正曲线线性范围为 0.4～3.2μg/25mL,硼的校测限为 0.08ng.此法用于复合硼肥的分析,结果令人满意.     

Investigation of Fasciola hepatica sample preparation for two-dimensional electrophoresis

This paper investigates the preparation of Fasciola hepatica samples for two-dimensional electrophoresis (2-DE). Whole samples were prepared by both hot sodium dodecyl sulfate (SDS) solubilisation and precipitation using trichloroacetic acid (TCA) to remove nonprotein contaminants and to inactivate endogenous proteases. Sample preparation had a marked influence on the 2-DE gel profile. TCA precipitation resulted in no measurable improvement in the profile observed, compared to the untreated control. Solubilisation of sample with hot SDS increased the number of protein spots, as did TCA precipitation with the addition of phosphotungstic acid. The preparation of excretory-secretory (ES) products poses problems due to both high salt concentrations and low protein concentration. All precipitation methods used to overcome this gave similar profiles, except acetone alone, which caused depletion of the larger proteins. TCA in acetone gave the best result, similar to that obtained by centrifugal filtration of the sample. Overcrowding of spots in some regions of the 2-DE gel occurred in the whole Fasciola hepatica sample. This problem was alleviated by differential solubilisation, which also resulted in the enrichment of some proteins.     

Radiopharmaceuticals for renal studies: Evaluation of protein binding

Determination of total in vitro protein binding was evaluated for the following radiopharmaceuticals:^99mTc-diethylenetriaminepentaacetic acid (DTPA),^99mTc-dimercaptosuccinic acid (DMSA),^99mTc-glucoheptonate (GH) and^99mTc-fosfomycin (PHO). For that they were incubated wtih human serum at 37°C. After three and sixty minutes of incubation, the bound fraction was evaluated by two different methods: gel filtration and precipitation with trichloroacetic acid (TCA). The percentage of the^99mTc-kidney agents bound by human serum proteins is different for each one. Determination by TCA precipitation always leads to higher results. For renal imaging agents (DMSA, GH and PHO) the percentage of binding by each serum proteic constituent was also evaluated by electrophoretic analysis. All proteic constituents of human serum bind with those radiopharmaceuticals but the percentage of binding is different in accordance with both the radiopharmaceutical and the proteic constituent.     

Protein extraction from Phoenix dactylifera L. leaves, a recalcitrant material, for two-dimensional electrophoresis

This work was aimed at optimizing a protein extraction procedure for date palm (Phoenix dactylifera L.) leaves, a highly recalcitrant plant tissue for 2-DE. Five protein extraction protocols based on different protein precipitation agents (TCA/acetone vs. phenol (Ph) methods) and protein resolubilization methods (physical treatments, e.g., sonication, shaking and/or heating) were tested. Ph/SDS extraction with methanol/ammonium acetate precipitation, followed by DOC preincubation and TCA/acetone precipitation and, finally, solubilization by shaking in rehydration solution was found to be the best protein extraction method. We conclude that DOC with TCA/acetone precipitation step eliminates interfering compounds, thus allowing efficient resolubilization of date palm leaf proteins. This method could be appropriate for proteomic studies such as date palm colonization by entomopathogenic fungi.     

反相高效液相色谱法同时快速测定食品中常见的8种食品添加剂

 采用反相高效液相色谱法测定食品中常见的 8种食品添加剂 :糖精、甜味素、苯甲酸、山梨酸、香兰素、咖啡因、胭脂红和日落黄。实验采用Shim packCLC ODS分析柱 ,以甲醇 乙酸铵 (pH 7 0 ) (体积比为 44∶5 6 )为流动相 ,在UV 2 2 0nm处检测。样品经Carrez试剂处理去除杂质后直接进样 ,一次进样分析仅需 8min。平均回收率为 91 9%～ 10 8 5 % ,相对标准偏差小于 4% (n =5 )。     

Evaluation of extraction procedures for 2‐DE analysis of aphid proteins

Protein sample preparation is a crucial step in a 2‐DE proteomics approach. In order to establish a routine protocol for the application of proteomics analysis to aphids, this study focuses on the specific protein extraction problems in insect tissues and evaluates four methods to bypass them. The approaches of phenol extraction methanol/ammonium acetate precipitation (PA), TCA/acetone precipitation, PEG precipitation, and no precipitation were evaluated for proteins isolation and purification from apterous adult aphids, Sitobion avenae. For 2‐DE, the PA protocol was optimal, resulting in good IEF and clear spots. PA method yielded the greatest amount of protein and displayed most protein spots in 2‐DE gels, as compared with the TCA/acetone precipitation, PEG precipitation and no precipitation protocols. Analysis of protein yield, image quality and spot numbers demonstrate that the TCA/acetone precipitation protocol is a reproducible and reliable method for extracting proteins from aphids. The PEG precipitation approach is a newly developed protein extraction protocol for aphids, from which more unique protein spots can be detected, especially for detection of acid proteins. These protocols are expected to be applicable to other insects or could be of interest to laboratories involved in insect proteomics, despite the amounts and types of interfering compounds vary considerably in different insects.