Publications by authors named "Asuka Nakayama"

We report a novel vibration control technique of an artificial auditory cochlear epithelium that mimics the function of outer hair cells in the organ of Corti. The proposed piezoelectric and trapezoidal membrane not only has the acoustic/electric conversion and frequency selectivity of the previous device developed mainly by one of the authors and colleagues, but also has a function to control local vibration according to sound stimuli. Vibration control is achieved by applying local electrical stimuli to patterned electrodes on an epithelium made using micro-electro-mechanical system technology.

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Patients with type 2 diabetes mellitus (DM) exhibit modification of high-density lipoprotein (HDL), which is likely to have an important role in the development of atherosclerotic cardiovascular disease (ASCVD). Excess production of aldosterone (Ald) results in hypertension as well as ASCVD. However, the biological activity of modified HDL in steroidogenesis is not clear.

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A recent clinical study indicated that an angiotensin II (Ang II) type 1 (AT) receptor-neprilysin inhibitor (ARNi) designated LCZ696 (sacubitril/valsartan, as combined sodium complex) was superior to enalapril at reducing the risks of death and hospitalization due to heart failure. Therefore, we investigated the possible mechanisms of the beneficial effect of LCZ696, in which the inhibition of neprilysin enhances atrial natriuretic peptide (NP) or brain NP (ANP or BNP)-evoked signals that can block Ang II/AT receptor-induced aldosterone (Ald) synthesis in human adrenocortical cells. The binding affinity of valsartan+LBQ657 (active moiety of sacubitril) to the AT receptor was greater than that of valsartan alone in an AT receptor-expressing human embryonic kidney cell-based assay.

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Bifunctional angiotensin II (Ang II) type 1 (AT1) receptor blockers (ARBs) that can block the activation of not only AT1 receptor, but also neprilysin, which metabolizes vasoactive peptides including atrial natriuretic peptide (ANP), are currently being developed. However, the usefulness of the inactivation of ANP in addition to the AT1 receptor with regard to aldosterone (Ald) synthesis is not yet clear. We evaluated the inhibitory effects of various ARBs combined with or without ANP on Ang II-induced adrenal Ald synthesis using a human adrenocortical cell line (NCI-H295R).

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Introduction: The recently approved angiotensin II (Ang II) type 1 (AT1) receptor blocker (ARB) azilsartan strongly reduces blood pressure (BP) in patients with hypertension. We previously reported that azilsartan showed unique binding behavior to the AT1 receptor because of its 5-oxo-1,2,4-oxadiazole moiety. However, the ability of azilsartan to block Ang II-dependent AT1 receptor activation is not yet clear.

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Although there have been many studies that showed a close association between gastroesophageal reflux disease (GERD) symptoms and chronic cough, it has been unknown whether acute cough is also associated with GERD. The aim of this study was to evaluate the relationship between GERD and respiratory symptoms in general practice. 1725 consecutive patients who first attended our hospital were enrolled in the present study.

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Background/aims: Gastric acid plays an important part in the prevention of bacterial colonization of the gastrointestinal tract. If these bacteria have an ability of hydrogen (H2) fermentation, intraluminal H2 gas might be detected. We attempted to measure the intraluminal H2 concentrations to determine the bacterial overgrowth in the gastrointestinal tract.

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Objective: Gastric acid plays an important part in the prevention of bacterial colonization of the gastrointestinal tract. If these bacteria have an ability of hydrogen (H2) fermentation, intraluminal H2 gas might be detected. We attempted to measure the intraluminal H2 concentrations to determine the bacterial overgrowth in the gastrointestinal tract.

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Unlabelled: During esophageal acid clearance, salivation plays an important role in defending the esophageal mucosa. Nizatidine, a histamine H2 receptor antagonist, inhibits acetylcholine esterase, with a resultant increase in acetylcholine. We experienced a patient with gastroesophageal reflux disease (GERD) and impaired salivary secretion who has been successfully treated with nizatidine.

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Porcine embryonic fibroblasts (PEF) are important as donor cells for nuclear transfer for generation of genetically modified pigs. In this study, we determined an optimal protocol for transfection of PEF with the Amaxa Nucleofection system, which directly transfers DNA into the nucleus of cells, and compared its efficiency with conventional lipofection and electroporation. Cell survival and transfection efficiency were assessed using dye-exclusion assay and a green fluorescent protein (GFP) reporter construct, respectively.

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