Effective Tumor Targeting by EphA2-Agonist-Biotin-Streptavidin Conjugates

We recently reported on a potent synthetic agent, 135H11, that selectively targets the receptor tyrosine kinase, EphA2. While 135H11 possesses a relatively high binding affinity for the ligand-binding domain of EphA2 (Kd~130 nM), receptor activation in the cell required the synthesis of dimeric versions of such agent (namely 135H12). This was expected given that the natural ephrin ligands also need to be dimerized or clustered to elicit agonistic activity in cell. In the present report we investigated whether the agonistic activity of 135H11 could be enhanced by biotin conjugation followed by complex formation with streptavidin. Therefore, we measured the agonistic EphA2 activity of 135H11-biotin (147B5) at various agent/streptavidin ratios, side by side with 135H12, and a scrambled version of 147B5 in pancreatic- and breast-cancer cell lines. The (147B5)_n-streptavidin complexes (when n = 2, 3, 4, but not when n = 1) induced a strong receptor degradation effect in both cell lines compared to 135H12 or the (scrambled-147B5)₄-streptavidin complex as a control, indicating that multimerization of the targeting agent resulted in an increased ability to cause receptor clustering and internalization. Subsequently, we prepared an Alexa-Fluor-streptavidin conjugate to demonstrate that (147B5)₄-AF-streptavidin, but not the scrambled equivalent complex, concentrates in pancreatic and breast cancers in orthotopic nude-mouse models. Hence, we conclude that these novel targeting agents, with proper derivatization with imaging reagents or chemotherapy, can be used as diagnostics, and/or to deliver chemotherapy selectively to EphA2-expressing tumors.     

人肝细胞中总砷及砷代谢产物分析方法研究

本工作研究了冷消解、微波消解、高压密闭消解方法对超声破碎后细胞中砷的ICP-MS测定的影响,并与直接进样测定结果作对比.结果表明,微波消解法和高压密闭消解法效果较好,测定的精密度以RSD表示,分别为2.1%和1.2%;日间6次测定的精密度分别为1.2%和2.0%;元素加标回收率均在95.7%～108.1%范围.用4种消解方法对应的ICP-MS方法检出限介于0.74～0.93 μg/l之间,符合痕量分析要求.本工作还建立了高效液相色谱(HPLC)与电感耦合等离子体质谱(ICP-MS)联用技术对1 μmol/L染砷组细胞样品中的砷化学形态进行了初步探讨,发现细胞内除了存在无机砷(As(Ⅲ)和As(Ⅴ))外,同时存在二甲基砷(DMA)和一种甲基砷中间代谢产物.     

A new method providing complementary explanation of the blood-enriching function and mechanism of unprocessed Angelica sinensis and its four kinds of processed products based on tissue-integrated metabolomics and confirmatory analysis

Angelica sinensis (AS) is a common Traditional Chinese Medicine used for tonifying blood in China. Unprocessed AS and its four kinds of processed products (ASs) are used to treat blood deficiency syndrome in the country. The different blood-tonifying mechanisms of ASs remain unclear. In this work, a novel method integrating metabolomics and hematological and biochemical parameters was established to provide a complementary explanation of blood supplementation mechanism of ASs. Our results revealed that different ASs exhibited various blood supplementation effect, and that AS parched with alcohol demonstrated the best blood supplementation effect. Eight metabolites from liver tissue and 12 metabolites from spleen tissue were considered to be potential biomarkers. These biomarkers were involved in four metabolic pathways. Correlation analysis results showed that l -aspartic acid and l -alanine (spleen tissue), linoleic acid, and l -cystathionine (liver tissue) exhibited a high positive or negative correlation with the aforesaid biochemical indicators. The blood-supplementation effect mechanism of ASs were related to four metabolic pathways. l -Aspartic acid and l -alanine (spleen tissue), linoleic acid, and l -cystathionine (liver tissue) were the four key metabolites associated with the blood supplementation effect of ASs. This study gives a complementary explanation of the blood supplementation effect and mechanism of action of ASs.     

基于三维可视化技术的外科教学研究

为调动学生对肝胆外科学习的积极性, 加深对肝脏影像学及外科治疗的理解及认识, 提高学习效率及成绩, 提出一种将三维可视化技术与传统教学相结合的新颖教学方法。 选取吉林大学医学院临床 5 年制学生90 名进行随机对照研究, 对照组采用传统肝脏外科授课方法教学, 实验组采用三维可视化技术结合传统授课方法进行教学。 学习结束后, 两组学生进行标准化考试, 并采用调查问卷进行教学效果评价。 结果显示, 实验组学生的综合考试成绩及优秀率均高于对照组, 实验组教学效果优于对照组。     

Simultaneous determination of thirteen substances related to NAFLD in mouse brain tissue using 3-aminobutyric acid as internal standard by HPLC–FLD

Disorders of certain branched-chain amino acids may be associated with the occurrence and development of non-alcoholic fatty liver disease. Measurement of related branched-chain amino acid levels could provide a reference for the clinical and scientific research of the non-alcoholic fatty liver disease. An established HPLC–FLD method was used to quantify aspartic acid, glutamate, glutamine, glycine, taurine, tyrosine, 4-amino butanoic acid, tryptophan, methionine, valine, phenylalanine, isoleucine and leucine in mouse brain tissue. Brain tissue samples mixed with internal standard (3-aminobutyric acid) were processed, then derivatized with 2-O-phthaldialdehyde, and finally separated on an ODS2 column through gradient elution at a flow rate of 1.0 ml·min⁻¹. The excitation and emission wavelengths were set at 340 and 455 nm, respectively. The mobile phase A was 100% methanol and the mobile phase B consisted of 30 mmol·L⁻¹ sodium acetate (pH 6.8). The injection volume was 20 μl and the single run time was 45 min. Several parameters, accuracy, precision, and stability, were verified and the results showed the established method had good sensitivity and resolution for all of the 13 compounds and internal standard in mouse brain.     

Simultaneous quantitation of glycyrrhetic acid and puerarin in plasma using ultra flow liquid chromatography tandem mass spectrometry and application in a pharmacokinetics study in healthy and alcoholic liver injury rats

A rapid, sensitive, and accurate ultra flow liquid chromatography tandem mass spectrometry (UFLC–MS/MS ) method was developed and validated for simultaneous quantitation of glycyrrhetic acid and puerarin in plasma derived from healthy and alcoholic liver injury rats. Plasma samples from healthy and model rats were deproteinated with methanol using liquiritin as an internal standard. Chromatography separation was performed by a Waters BEH (ethylene-bridged hybrid) C₁₈ column (2.1 × 50 mm; 1.7 μm) using a gradient elution from acetonitrile and water (containing 0.1% formic acid) and at a flow rate of 0.4 mL/min. Quantitation was performed on a Triple Quad 4500 tandem mass spectrometer coupled with an electrospray ionization source in negative multiple reaction monitoring mode. Specificity, carryover, dilution integrity, recovery, linearity, precision and accuracy, matrix effect, and stability were within acceptable limits. The newly established method was successfully applied to a pharmacokinetics study to investigate glycyrrhetic acid and puerarin in healthy and alcoholic liver injury rats.     

吸附型“人工肝”辅助材料的制备及其性能研究──(Ⅳ)VD共聚物及其醇解物(SVD)吸附剂对芳香氨基酸的吸附性能

本文选择醋酸乙烯酯／二乙烯苯共聚物（VD）及其醇解物（SVD）为亲水性吸附剂,考察了它们对水溶液及血清中芳香氨基酸（AAA）的吸附性能,实验结果表明：SVD比VD吸附AAA的功效高,该吸附剂不仅在水溶液及在血清中选择性吸附AAA较高,血液相容性亦良好。     

中老年人脂肪肝与血清脂蛋白的临床探讨

测定了经Ｂ超检查发现脂肪肝的４０例中老年病例血清脂蛋白含量,并与正常对照组比较。结果显示,除ＨＤＬ外,ＴＣ、ＴＧ、ＬＤＬ均显著升高,故积极控制血清脂蛋白的升高,是预防和控制脂肪的重要措施。     

慢性肝病患者血中TNF、LPO水平的变化及其相互关系

为探讨脂质过氧化与肿瘤坏死因子（ＴＮＦ）释放之间的关系,观察了７２例慢性肝病患者抗氧化治疗前后血中过氧化脂质（ＬＰＯ）和ＴＮＦ水平。结果表明,治疗２～３月后,所有患者血中ＬＰＯ、ＴＮＦ水平均下降,以补硒抗氧化治疗组最明显,与常规治疗组比较有显著差别（Ｐ〈０．０５）。提示慢肝患者体内脂质过氧化状态可能影响免疫介质ＴＮＦ的释放。     

肝源性磷脂酰胆碱的分离纯化及其对肝癌细胞抑制作用的评价

采用氧化铝柱色谱法以95%乙醇作为洗脱剂分离纯化了肝源性磷脂酰胆碱(PC)，并采用GF254硅胶板薄层色谱法以氯仿-甲醇-水（65∶25∶4，体积比)为展开剂测定了PC的纯度。结果表明以95%乙醇洗脱氧化铝色谱柱中的磷脂时,PC可完全与磷脂酰乙醇胺分离,其纯度和得率均高于80%。采用四甲基偶氮唑蓝比色法(MTT法)测定了不同浓度的PC对大鼠肝癌CBRH-7919 胞增殖的影响,并与人白血病K562细胞做比较,发现肝源性PC对肝癌细胞的生长具有明显的抑制作用,且存在时间-剂量依赖关系。