42 research outputs found

    Evaluation of amyloid β42 aggregation inhibitory activity of commercial dressings by a microliter-scale high-throughput screening system using quantum-dot nanoprobes

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    The aggregation and accumulation of amyloid β (Aβ) in the brain is a trigger of pathogenesis for Alzheimer’s disease. Previously, we developed a microliter-scale high-throughput screening (MSHTS) system for Aβ42 aggregation inhibitors using quantum-dot nanoprobes. The MSHTS system is seldom influenced by contaminants in samples and is able to directly evaluate Aβ42 aggregation inhibitory activity of samples containing various compounds. In this study, to elucidate whether the MSHTS system could be applied to the evaluation of processed foods, we examined Aβ42 aggregation inhibitory activity of salad dressings, including soy sauces. We estimated the 50% effective concentration (EC50) from serial diluted dressings. Interestingly, all 19 commercial dressings tested showed Aβ42 aggregation inhibitory activity. It was suggested that EC50 differed by as much as 100 times between the dressings with the most (0.065 ± 0.020 v/v%) and least (6.737 ± 5.054 v/v%) inhibitory activity. The highest activity sample is traditional Japanese dressing, soy sauce. It is known that soy sauce is roughly classified into a heat-treated variety and a non-heat-treated variety. We demonstrated that non-heat-treated raw soy sauce exhibited higher Aβ42 aggregation inhibitory activity than heat-treated soy sauce. Herein, we propose that MSHTS system can be applied to processed foods

    The Automatic System for Calculation of Instrumental Seismic Intensity Using K-NET Strong-motion Data

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    Microwave-Mediated Continuous Hydrogen Abstraction Reaction from 2-PrOH Catalyzed by Platinum on Carbon Bead

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    We developed a microwave-mediated continuous hydrogen production method from 2-PrOH using platinum on a spherical carbon-bead catalyst. The catalyst cartridge consisted of helical glass part, and straight glass part (helix−straight cartridge) was newly developed for the effective microwave heating of 2-PrOH in the presence of 5% Pt/CB. The microwave resonance was properly adjusted within 2.4−2.5 GHz using the helix−straight cartridge with the glass resonance-adjuster tube. The reaction was conducted by the irradiation of only 10 W of single-frequency microwaves and the catalyst was used continuously for at least 13 h without any loss of catalyst activity

    Glass Transitions in Aqueous Solutions of Protein (Bovine Serum Albumin)

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    Measurements by adiabatic calorimetry of heat capacities and enthalpy relaxation rates of a 20% (w/w) aqueous solution of bovine serum albumin (BSA) by Kawai, Suzuki, and Oguni [Biophys. J. 2006, 90, 3732] have found several enthalpy relaxations at long times indicating different processes undergoing glass transitions. In a quenched sample, one enthalpy relaxation at around 110 K and another over a wide temperature range (120-190 K) were observed. In a sample annealed at 200-240 K after quenching, three separated enthalpy relaxations at 110, 135, and above 180 K were observed. Dynamics of processes probed by adiabatic calorimetric data are limited to long times on the order of 10(3) s. A fuller understanding of the processes can be gained by probing the dynamics over a wider time/frequency range. Toward this goal, we performed broadband dielectric measurements of BSA-water mixtures at various BSA concentrations over a wide frequency range of thirteen decades from 2 mHz to 1.8 GHz at temperatures from 80 to 270 K. Three relevant relaxation processes were detected. For relaxation times equal to 100 s, the three processes are centered approximately at 110, 135, and 200 K, in good agreement with those observed by adiabatic calorimetry. We have made the following interpretation of the molecular origins of the three processes. The fastest relaxation process having relaxation time of 100 or 1000 s at ca. 110 K is due to the secondary relaxation of uncrystallized water (UCW) in the hydration shell. The intermediate relaxation process with 100 s relaxation time at ca. 135 K is due to ice. The slowest relaxation process having relaxation time of 100 s at ca. 200 K is interpreted to originate from local chain conformation fluctuations of protein slaved by water. Experimental evidence supporting these interpretations include the change of temperature dependence of the relaxation time of the UCW at approximately T(gBSA) approximate to 200 K, the glass transition temperature of protein in the hydration shell,,BSA similar to that found for the secondary relaxation of water in a mixture of myoglobin in glycerol and water [Swenson et al. J. Phys.: Condens. Matter 2007, 19, 205109; Ngai et al. J. Phys. Chem. B 2008, 112, 3826]. The data all indicate in hydrated BSA or other proteins that the secondary relaxation of water and the conformation fluctuations of the protein in the hydration shell are inseparable or symbiotic processes

    Markedly reduced ventricular arrhythmia during the peripartum period in a pregnant woman with Andersen-Tawil syndrome

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    Andersen-Tawil syndrome (ATS), also known as long QT syndrome type 7, is a rare autosomal dominant disease caused by a KCNJ2 mutation. The characteristic triad of ATS is periodic paralysis, dysmorphic features, and ventricular arrhythmia. We describe a case of a woman with Andersen-Tawil syndrome and a history of syncope whose pregnancy was complicated with frequent premature ventricular contractions (PVCs) and nonsustained ventricular tachycardia (NSVT). Her PVCs and NSVT were significantly decreased during the peripartum period, especially during labor. We treated her with beta-blockers throughout her pregnancy, and she experienced no complications. Although the mechanism underlying the decreased PVCs and NSVT in pregnancy has not been elucidated, women with ATS may have less arrhythmic event risk during pregnancy

    Magnesium sulfate-induced blocked premature atrial contractions resulting in fetal bradyarrhythmia

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    Here, we present a rare case of fetal bradyarrhythmia following magnesium sulfate therapy for preterm labor. After we switched treatment from ritodrine hydrochloride to magnesium sulfate at 25 weeks' gestation, the fetal heart rate dropped from 150 bpm to 80–100 bpm. Fetal echocardiography and magnetocardiography indicated bigeminy and trigeminy of blocked premature atrial contractions. It is well known that magnesium sulfate decreases the baseline and variability of fetal heart rate. Studies have reported a substantial decrease of 2–15 bpm in the baseline fetal heart rate, and magnesium has various effects on fetal heart rate patterns with a lower baseline fetal heart rate within the normal range of 110–160 bpm. This is the first report of magnesium sulfate-induced fetal bradyarrhythmia by prolongation of the refractory period of the atrioventricular node in the case of blocked premature atrial contractions. Clinicians should consider fetal bradyarrhythmia when the baseline fetal heart rate drops to <100 bpm after magnesium sulfate administration
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