MSCTP参数及基质金属蛋白酶在急性脑缺血介入治疗前后的变化和对预后的预测价值分析

选取急性脑缺血患者122例,均采取介入治疗,治疗前后均行多层螺旋CT灌注成像(MSCTP)检查,并检测患者血清基质金属蛋白酶-9(MMP-9)和基质金属蛋白酶抑制剂-1(TIMP-1)水平.结果 发现,介入治疗后7d,患者缺血边缘区和缺血中央区的相对脑血流量(rCBF)高于介入治疗前,相对平均通过时间(rMTT)短于介...     

宿主防御肽模拟聚合物与蛋白酶K联用抗生物被膜

采用双（三甲基硅基）胺基锂（LiHMDS）引发的α-氨基酸N-羧酸酐（NCA）快速开环聚合方法合成宿主防御肽模拟聚合物,该聚合物呈现窄分子量分布。抗菌实验结果表明,该聚合物对耐甲氧西林金黄色葡萄球菌（MRSA）浮游菌和持留菌有高杀菌活性,且遵循破膜杀菌机制。实验证明,1.25 U/mL的蛋白酶K在人工尿液环境中可分散MRSA成熟生物被膜。蛋白酶K与聚合物协同作用实现了人工尿液中成熟生物被膜的清除。     

Purification and Characterization of a Proteolytic Enzyme from Fig Latex

Ficin is an important component of plants in Ficus family such as fig latex. It is of special significance in medicine and industry because it exhibits activity throughout a wide range of temperature and pH values. In this work, we purified a component of ficin from the latex homogeneity of Shandong fig trees, and the properties of the purified ficin were studied. The current findings revealed that heavy metal ions were able to inhibit ficin, while DTT, L-cysteine, and β-ME were found to promote ficin activity. It was also observed that the half life of ficin at 65 °C was longer than 1 h and the Michaelis constant（Km） for casein hydrolyzation was determined to be 1.56 mg/mL. Our study shows that this purified ficin is a cysteine protease.     

测定海产品中5种砷形态国家标准方法的改进北大核心CSCD

国家标准GB5009.11-2014测定食品中砷形态含量时,前处理方法需经放置过夜、热提取、离心、萃取及过滤等较多步骤,耗时较长,且测定方法高效液相色谱-电感耦合等离子体质谱法(HPLC-ICP-MS)中流动相需配制4种不同含量的无机盐,还须调节流动相酸度,较为复杂.针对上述问题,改进了国家标准前处理方法,优化了国家标准第二法的色谱条件,提出了基于微波辅助酶提取-HPLC-ICP-MS快速测定食品中5种砷形态含量的方法.将样品1.0 g、链霉蛋白酶E酶0.004 g和水20 mL置于微波提取仪中,于35℃提取45 min,提取液离心10 min,再经0.45μm水性滤膜过滤即得样品溶液.以Hamilton PRP-X100色谱柱为固定相,体积比99∶1的2.0 mmol􀅰L^(-1)的磷酸二氢铵溶液(pH 8.0)-乙醇的混合液为流动相等度洗脱,按仪器工作条件进行测定.结果表明:5种砷形态的标准曲线的线性范围均为2.5~30.0μg·L^(-1),检出限(3s/k)为0.50~0.60μg·L^(-1).按标准加入法进行回收试验,回收率为90.0%~103%,测定值的相对标准偏差(n=5)为0.80%~5.0%.方法用于实际样品的分析,并与GB 5009.11-2014中第二法的测定结果进行比对,结果表明改进后的方法与GB 5009.11-2014不存在显著性差异(P>0.05).