294 research outputs found

    METABOLIC PROPERTIES OF A RIBONUCLEIC ACID FRACTION IN YEAST

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    Applicability of molding procedures in laboratory mix tests for quality control and assurance of the deep mixing method

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    The deep mixing method (DMM) has been applied in many construction projects. The laboratory mix test is essential to the quality control and quality assurance (QC/QA) of deep mixing methods. The procedures used for the preparation of specimens in the laboratory mix test greatly affect the physical and mechanical properties of the stabilized soils. Different procedures are applied in different countries/regions. With the increasingly globalized DMM market, it is desirable that a common understanding of the nature of the laboratory mix test and internationally accepted guidelines to conduct it be established in order to guarantee the QC/QA of DMMs. As part of an international collaborative study, the influence of different molding techniques for the laboratory preparation of specimens was studied. Five different molding techniques were tested in four organizations. The results showed that the molding techniques considerably influenced the magnitude and variation of the unconfined compressive strength and the wet unit weight of the stabilized specimens. The applicability of the molding techniques was discussed in terms of their undrained shear strength and the liquidity index of the soil and binder mixture, and the usefulness of the techniques was demonstrated. (C) 2015 The Japanese Geotechnical Societ

    Effect of spermine-derived AGEs on oxidative stress and polyamine metabolism

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    © 2017 The Royal Society of Chemistry. Non-enzymatic glycation between proteins and carbohydrates, such as advanced glycation end products (AGEs), are naturally occurring compounds implicated in aging and numerous degenerative diseases. Methyl glyoxal (MG), which is an intermediate of the AGE biosynthetic pathway, is known to react with primary amines of proteins to create a wide range of AGE modifications, such as carboxyethyl lysine (CEL) and methylglyoxal-derived lysine dimer (MOLD). As a means to investigate and probe the ROS production pathways of AGEs, low molecular weight compounds carboxyethyl spermine (CES) and methylglyoxal-derived spermine dimer (MOSD) were synthesized, which replace lysine with another highly nucleophilic biological amine, spermine (SPM). Contrary to expectations, results show CES- and MOSD-induced oxidative stress proceeds through different pathways. As such, we have developed useful probes that can be used to better understand and investigate pathways related to acrolein-based oxidative stress and/or polyamine metabolic pathways

    A Reduction-Based Sensor for Acrolein Conjugates with the Inexpensive Nitrobenzene as an Alternative to Monoclonal Antibody

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    © 2016 The Author(s).Acrolein, a highly toxic α, β-unsaturated aldehyde, has been a longstanding key biomarker associated with a range of disorders related to oxidative stresses. One of the most promising methods for detecting acrolein involves the use of antibodies that can recognize the acrolein-lysine conjugate, 3-formyl-3, 4-dehydropiperidines (FDP), within oxidatively stressed cells and tissues from various disease states. We have uncovered here that FDP could reduce nitroarenes in high yields at 100 °C in the presence of excess CaCl 2 as a Lewis acid promoter. This unique transformation allowed for the development of a de novo method for detecting levels of FDPs generated from proteins in urine or blood serum samples. Thus we successfully converted a non-fluorescent and inexpensive 4-nitrophthalonitrile probe to the corresponding fluorescent aniline, thereby constituting the concept of fluorescent switching. Its sensitivity level (0.84 nmol/mL) is more than that of ELISA assays (3.13 nmol/mL) and is already equally reliable and reproducible at this early stage of development. More importantly, this method is cost effective and simple to operate, requiring only mixing of samples with a kit solution. Our method thus possesses potential as a future alternative to the more costly and operatively encumbered conventional antibody-based methods

    Cancer cell targeting driven by selective polyamine reactivity with glycine propargyl esters

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    © 2017 The Royal Society of Chemistry. Rapidly growing cancer cells have increased levels of intracellular polyamines compared to normal, healthy tissues. Based on the selective reactivity of glycine propargyl esters, probes were synthesized that show evidence for selective polyamine reactivity, which was then applied for selective cancer cell imaging studies

    Cell surface and in vivo interaction of dendrimeric N-glycoclusters

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    © 2015 Springer Science+Business Media New York. While many examples have been reported that glycoclusters interact with target lectins more strongly than single molecules of glycans, through multivalency effects, literature examples to support lectin interactions/modulations on cell surface and in live animals is quite rare. Our N-glycoclusters, which were efficiently prepared by immobilizing 16 molecules of the asparagine-linked glycans (N-glycans) onto a lysine-based dendron template through histidine-mediated Huisgen cycloaddition, were shown to efficiently detect platelet endothelial cell adhesion molecule (PECAM) on human umbilical vein endothelial cells (HUVEC) as a α(2-6)-sialylated oligosaccharides recognizing lectin. Furthermore, the identity of the N-glycans on our N-glycoclusters allowed control over organ-selective accumulation and serum clearance properties when intravenously injected into mice

    Influence of SIGLEC9 polymorphisms on COPD phenotypes including exacerbation frequency.

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    BACKGROUND AND OBJECTIVE: The exacerbation-prone phenotype of COPD is particularly important, as exacerbations lead to poor quality of life and disease progression. We previously found that COPD patients who lack Siglec-14, a myeloid cell protein that recognizes bacteria and triggers inflammatory responses, are less prone to exacerbation. We hypothesized that the variations in other SIGLEC genes could also influence COPD exacerbation frequency, and investigated the association between SIGLEC9 polymorphisms and the exacerbation-prone phenotype of COPD. METHODS: We examined whether SIGLEC9 polymorphisms affect the frequency of COPD exacerbation in 135 subjects within our study population, and also analysed the correlation between the genotypes and the severity of airflow obstruction and emphysema in 362 Japanese smokers including 244 COPD patients. The association between these single nucleotide polymorphisms (SNPs) and COPD phenotypes were also assessed in a Caucasian population of ECLIPSE study. The effects of these coding SNPs (cSNPs) on Siglec-9 protein functions were analysed using in vitro assays. RESULTS: The G allele of rs2075803 and rs2075803 G/rs2258983 A(GA) haplotype in SIGLEC9 was associated with higher frequency of exacerbations and the extent of emphysema in COPD. These results did not replicate in the ECLIPSE study. A myeloid cell line expressing the Siglec-9 variant corresponding to GA haplotype produced more TNF-α than the one expressing the variant corresponding to the other major haplotype. CONCLUSION: The SIGLEC9 rs2075803 G/rs2258983 A haplotype, which corresponds to a Siglec-9 variant that is less effective at suppressing inflammatory response, may be a risk factor for the development of emphysema

    Polyamine modification by acrolein exclusively produces 1,5-diazacyclooctanes: A previously unrecognized mechanism for acrolein-mediated oxidative stress

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    Acrolein, a toxic unsaturated aldehyde generated as a result of oxidative stress, readily reacts with a variety of nucleophilic biomolecules. Polyamines, which produced acrolein in the presence of amine oxidase, were then found to react with acrolein to produce 1,5-diazacyclooctane, a previously unrecognized but significant downstream product of oxidative stress. Although diazacyclooctane formation effectively neutralized acrolein toxicity, the diazacyclooctane hydrogel produced through a sequential diazacyclooctane polymerization reaction was highly cytotoxic. This study suggests that diazacyclooctane formation is involved in the mechanism underlying acrolein-mediated oxidative stress. © 2014 the Partner Organisations

    In Situ Ligation of High- and Low-Affinity Ligands to Cell Surface Receptors Enables Highly Selective Recognition

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    © 2017 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. This paper reports an entirely unexplored concept of simultaneously recognizing two receptors using high- and low-affinity ligands through ligating them in situ on the target cell surface. This de novo approach is inspired by the pretargeting strategy frequently applied in molecular imaging, and has now evolved as the basis of a new paradigm for visualizing target cells with a high imaging contrast. A distinct advantage of using a labeled low-affinity ligand such as glycan is that the excess labeled ligand can be washed away from the cells, whereas the ligand bound to the cell, even at the milli molar affinity level, can be anchored by a bioorthogonal reaction with a pretargeted high-affinity ligand on the surface. Consequently, nonspecific background is minimized, leading to improved imaging contrast. Importantly, despite previously unexplored for molecular imaging, a notoriously weak glycan/lectin interaction can now be utilized as a highly selective ligand to the targets
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