No Apparent Correlation of kp with Steric Hindrance for Branched Acrylates

The Arrhenius parameters of the propagation rate coefficient, k_p, are determined via the pulsed laser polymerization—size exclusion chromatography (PLP‐SEC) method for five branched acrylates (tert‐butyl (tBA), isobornyl (iBoA), benzyl (BnA), 2‐ethylhexyl (EHA), and 2‐propylheptyl acrylate (PHA)) in 1 m solution in butyl acetate (BuAc) to complete the series, published by Haehnel et al. in 2014, of branched acrylates (isononyl (INA‐A), tridecyl (TDA‐A and TDN‐A), heptadecyl (C17A), and henicosyl acrylate (C21A)) in solution that do not show a trend in k_p. Furthermore, the propagation rate coefficients of the branched acrylates in 1 m solution are critically compared with the branched acrylates in bulk as well as branched methacrylates. A summary of the trends and family‐type behavior for the linear and branched (meth)acrylates as well as methacrylates with cyclic ester side chains is provided. For the branched acrylates in 1 m solution, no clear trends of the propagation rate coefficients, k_p, or Arrhenius parameters A and E_A are detectable and—in contrast to the corresponding methacrylates—there is no family‐type behavior observed in solution as well as in bulk.

     

New Insight into the ATRP of Monovinyl and Divinyl Monomers

New insights are provided into the atom transfer radical polymerizations of styrene with 1,6‐bismaleimidohexane, tri‐ethylene glycol dimethacrylate (tri‐EGDMA), and divinyl benzene (DVB) as branching agents. Gas chromatography, proton nuclear magnetic resonance spectroscopy, and triple detection size exclusion chromatography are used to analyze the polymerizations and the polymers. The polymerizations and molecular weights of polymers differ because of the different levels of intramolecular cyclization and initiator efficiencies (IEs) among the three polymerization systems. High IE increases polymerization rate and restrains gelation, thereby facilitating preparation of branched polymers with high molecular weights. Polymers in the tri‐EGDMA system exhibit the lowest molecular weight and the broadest polydispersity because of some evident primary chain residues, whereas polymers in the DVB system show the highest molecular weight because of the low amount of the primary chain residues and high IE. The absence of branching monomer units in the primary chain residue of all these polymerizations is confirmed.

     

骨肉瘤常用化疗药物作用的分子机制及用药方法选择

目的 研究常用骨肉瘤化疗药物作用的分子机制,对临床用药方式提供指导.方法 将骨肉瘤细胞混悬液与不同浓度吡柔比星、顺铂、卡铂、甲氨蝶呤、异环磷酰胺分别作用24、48、72 h后,用倒置显微镜观察细胞生长情况.用MTT法测定每一孔的吸光度值OD,制作生长曲线,并求出药物的IC50.用IC50浓度的药物分别作用于骨肉瘤细胞24、48和72 h后用流式细胞仪进行细胞周期分析,了解细胞的周期分布及细胞的增殖活性.免疫印迹技术观察细胞的PCNA、Bcl-2、Bax、cyclin D1、cyclin E的表达.结果 在倒置显微镜下观察不同药物浓度作用于的骨肉瘤细胞,比较细胞死亡数量于时间关系.MTT实验:不同时间组及不同浓度组与对照组相比,对MG-63细胞的生长抑制作用差异均具有显著性(P＜0.05),呈现不同剂量-时间效应关系.细胞周期分析:在细胞各期可见明显凋亡峰,细胞周期各期所占比例无明显变化,抑制作用呈剂量依赖性.蛋白免疫印迹:PCNA在不同药物组骨肉瘤表达与对照组相比明显不同,不同药物组Bax表达与对照组明显增加,Bcl-2表达减少.cyclin D1、cyclin E的表达明显减少.结论 吡柔比星对MG-63细胞的抑制率和时间关系密切,和浓度有一定的关系.同样剂量吡柔比星5d的效果比3d好.卡铂具有与顺铂类似的效应,但卡铂如果替代顺铂在化疗中的作用,卡铂的量必须是顺铂的25倍以上.甲氨蝶呤作用于骨肉瘤细胞MG-63后,随着药物浓度的增加和时间的延长,作用逐渐增强,尤其是用量和效果有明显关系.异环磷酰胺在体外对骨肉瘤细胞无明显抑制作用.     

Basophil activation test: Mechanisms and considerations for use in clinical trials and clinical practice

The basophil activation test (BAT) is a functional assay that measures the degree of degranulation following stimulation with allergen or controls by flow cytometry. It correlates directly with histamine release. From the dose-response curve resulting from BAT in allergic patients, basophil reactivity (%CD63⁺ basophils) and basophil sensitivity (EC₅₀ or similar) are the main outcomes of the test. BAT takes into account all characteristics of IgE and allergen and thus can be more specific than sensitization tests in the diagnosis of allergic disease. BAT reduces the need for in vivo procedures, such as intradermal tests and allergen challenges, which can cause allergic reactions of unpredictable severity. As it closely reflects the patients' phenotype in most cases, it may be used to support the diagnosis of food, venom and drug allergies and chronic urticaria, to monitor the natural resolution of food allergies and to predict and monitor clinical the response to immunomodulatory treatments, such as allergen-specific immunotherapy and biologicals. Clinical application of BAT requires analytical validation, clinical validation, standardization of procedures and quality assurance to ensure reproducibility and reliability of results. Currently, efforts are ongoing to establish a platform that could be used by laboratories in Europe and in the USA for quality assurance and certification.     

Biofilm and cell adhesion strength on dental implant surfaces via the laser spallation technique

ObjectiveThe aims of this study are to quantify the adhesion strength differential between an oral bacterial biofilm and an osteoblast-like cell monolayer to a dental implant-simulant surface and develop a metric that quantifies the biocompatible effect of implant surfaces on bacterial and cell adhesion.MethodsHigh-amplitude short-duration stress waves generated by laser pulse absorption are used to spall bacteria and cells from titanium substrates. By carefully controlling laser fluence and calibration of laser fluence with applied stress, the adhesion difference between Streptococcus mutans biofilms and MG 63 osteoblast-like cell monolayers on smooth and rough titanium substrates is obtained. The ratio of cell adhesion strength to biofilm adhesion strength (i.e., Adhesion Index) is determined as a nondimensionalized parameter for biocompatibility assessment.ResultsAdhesion strength of 143 MPa, with a 95% C.I. (114, 176), is measured for MG 63 cells on smooth titanium and 292 MPa, with a 95% C.I. (267, 306), on roughened titanium. Adhesion strength for S. mutans on smooth titanium is 320 MPa, with a 95% C.I. (304, 333), and remained relatively constant at 332 MPa, with a 95% C.I. (324, 343), on roughened titanium. The calculated Adhesion Index for smooth titanium is 0.451, with a 95% C.I. (0.267, 0.622), which increased to 0.876, with a 95% C.I. (0.780, 0.932), on roughened titanium.SignificanceThe laser spallation technique provides a platform to examine the tradeoffs of adhesion modulators on both biofilm and cell adhesion. This tradeoff is characterized by the Adhesion Index, which is proposed to aid biocompatibility screening and could help improve implantation outcomes. The Adhesion Index is implemented to determine surface factors that promote favorable adhesion of cells greater than biofilms. Here, an Adhesion Index ? 1 suggests favorable biocompatibility.     

Mutations in the COPII Vesicle Component Gene SEC24B are Associated with Human Neural Tube Defects

Neural tube defects (NTDs) are severe birth malformations that affect one in 1,000 live births. Recently, mutations in the planar cell polarity (PCP) pathway genes had been implicated in the pathogenesis of NTDs in both the mouse model and in human cohorts. Mouse models indicate that the homozygous disruption of Sec24b, which mediates the ER‐to‐Golgi transportation of the core PCP gene Vangl2 as a component of the COPII vesicle, will result in craniorachischisis. In this study, we found four rare missense heterozygous SEC24B mutations (p.Phe227Ser, p.Phe682Leu, p.Arg1248Gln, and p.Ala1251Gly) in NTDs cases that were absent in all controls. Among them, p.Phe227Ser and p.Phe682Leu affected its protein stability and physical interaction with VANGL2. Three variants (p.Phe227Ser, p.Arg1248Gln, and p.Ala1251Gly) were demonstrated to affect VANGL2 subcellular localization in cultured cells. Further functional analysis in the zebrafish including overexpression and dosage‐dependent rescue study suggested that these four mutations all displayed loss‐of‐function effects compared with wild‐type SEC24B. Our study demonstrated that functional mutations in SEC24B might contribute to the etiology of a subset of human NTDs and further expanded our knowledge of the role of PCP pathway‐related genes in the pathogenesis of human NTDs.     

EEC‐ and ADULT‐Associated TP63 Mutations Exhibit Functional Heterogeneity Toward P63 Responsive Sequences

TP63 germ‐line mutations are responsible for a group of human ectodermal dysplasia syndromes, underlining the key role of P63 in the development of ectoderm‐derived tissues. Here, we report the identification of two TP63 alleles, G134V (p.Gly173Val) and insR155 (p.Thr193_Tyr194insArg), associated to ADULT and EEC syndromes, respectively. These alleles, along with previously identified G134D (p.Gly173Asp) and R204W (p.Arg243Trp), were functionally characterized in yeast, studied in a mammalian cell line and modeled based on the crystal structure of the P63 DNA‐binding domain. Although the p.Arg243Trp mutant showed both complete loss of transactivation function and ability to interfere over wild‐type P63, the impact of p.Gly173Asp, p.Gly173Val, and p.Thr193_Tyr194insArg varied depending on the response element (RE) tested. Interestingly, p.Gly173Asp and p.Gly173Val mutants were characterized by a severe defect in transactivation along with interfering ability on two DN‐P63α‐specific REs derived from genes closely related to the clinical manifestations of the TP63‐associated syndromes, namely PERP and COL18A1. The modeling of the mutations supported the distinct functional effect of each mutant. The present results highlight the importance of integrating different functional endpoints that take in account the features of P63 proteins' target sequences to examine the impact of TP63 mutations and the associated clinical variability.     

急性心肌梗死和心房纤维性颤动患者CD62P、CD63与vWF检测的意义

目的 探讨急性心肌梗死(AMI)和心房纤维性颤动(AF)患者血小板膜糖蛋白CD62P、CD63与vWF临床检测的意义。方法采用流式细胞技术和夹心酶免疫吸附试验检测AMI和AF患者CD63、CD62P和vWF的变化。结果 AMI和AF患者的CD62P分别为11．29％和8．72％、CD63分别为8．72％和2．66％，明显高于对照组(3．37％和1．32％)，AMI组的vWF为167．83％，明显高于对照组(102．71％)，AF组为117．05％，与对照组比较无显著性差异。结论急性心肌梗死和心房纤维性颤动患者CD62P和CD63的表达水平明显增高，进一步证实CD62P和CD63为血栓形成的血小板活性物质，参与血栓性疾病的促凝血作用。