Publications by authors named "Hisao Oka"

Background: Dart-throwing motion from radial dorsiflexion to palmar flexion has recently attracted attention as a functional movement direction of the wrist joint. We developed a novel artificial muscle-type dynamic traction orthosis (DTSaM) that includes these movements. This prospective crossover controlled study aimed to compare the traction effects in the presence and absence of DTSaM using computed tomography.

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Objectives: Recently, the dart-throwing motion (DTM) has attracted attention as a functional direction of wrist joint motion. Consequently, we devised a new artificial muscle-type dynamic orthosis (Dynamic Traction Splint by Artificial Muscle, DTSaM) to reproduce DTM. This study analyzed the automatic motion of the wrist joint using a three-dimensional motion analysis system to assess how closely the DTSaM replicates DTM.

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Electromyography (EMG) and mechanomyography (MMG) have been used to directly evaluate muscle function through the electromechanical aspect of muscle contraction. The purpose of this study was to establish new absolute indices to describe muscle contraction performance during dynamic exercise by combining EMG and displacement MMG (dMMG) measured simultaneously using our previously developed MMG/EMG hybrid transducer system. Study participants were eight healthy male non-athletes (controls) and eight male athletes.

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Genipin was reacted with benzylamine and several amino acids to prepare gardenia blue (GB). The time-course of GB formation with benzylamine was monitored by high-performance liquid chromatography (HPLC), liquid chromatography time-of-flight mass spectrometry (LC-TOFMS), and H and C NMR measurements. In this experiment, we determined the molecular structures of some intermediates using accurate masses and additional NMR techniques such as heteronuclear multiple bond correlation (HMBC).

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Background: The accuracy of simulation-predicted fentanyl concentration in different types of surgical procedure is not fully understood. We wished to estimate the effect of different types of surgical procedure on the accuracy of such simulations.

Findings: Fifty patients who had undergone elective mastectomy or laparoscopic prostatectomy (American Society of Anesthesiologists physical status = I-II) were enrolled.

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Aim: Non-alcoholic steatohepatitis (NASH) increases cardiovascular risk regardless of risk factors in metabolic syndrome. However, the intermediary factors between NASH and vascular disease are still unknown because a suitable animal model has never been established. The stroke-prone (SP) spontaneously hypertensive rat, SHRSP5/Dmcr, simultaneously develops hypertension, acute arterial lipid deposits in mesenteric arteries, and NASH when feed with a high-fat and high-cholesterol (HFC) diet.

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The summation of the muscle force caused by an increase in the firing rate is named a tetanic contraction (tetanus), and the minimum stimulation frequency necessary to evoke an unfused/fused tetanus is related to the contraction time (CT) and relaxation time (RT) of the twitch. In particular, the fusion index (FI) is a very useful indicator, and it is used to evaluate the change in the muscle fiber component ratio. However, the measurement of the FI is invasive, because most patients experience pain during the electrical stimulation for tetanus.

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Background: Respiratory muscle strength has been used as a tool for evaluating respiratory rehabilitation in chronic obstructive pulmonary disease. However, mouth pressure measurement evaluated by maximum expiratory mouth pressure (PEmax) or inspiratory mouth pressure (PImax) offers an indirect method for measuring respiratory muscle strength. We demonstrated the evaluation of diaphragm contractility using a mechanomyogram (MMG), which is the mechanical signal generated by the motion of the diaphragm induced by the electric stimulation of the phrenic nerve.

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Background: Collateral ligament shortening causes extension contractures of the metacarpophalangeal joint, and dynamic flexion splinting has been widely used to treat these contractures; however, there are various problems with these approaches. We developed a novel, pneumatic-type dynamic traction and flexion splint to solve these problems.

Case Description And Methods: A total of 25 fingers were treated with the dynamic traction and flexion splint for 8 weeks.

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We have proposed a novel and first strategy of high-speed countercurrent chromatography (HSCCC) purification for the efficient and effective discovery of antioxidant from natural product based on on-line HPLC method with radical scavenging assay. To achieve a strategy for HSCCC purification, the antioxidants in materials are identified by on-line HPLC with DPPH radical scavenging assay. Then, the optimal condition of target peaks would be investigated for the two-phase solvent system, and purified by HSCCC.

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Background: To the best of our knowledge, there have been no reports on the pharmacokinetics and pharmacodynamics during the conversion from continuous intravenous infusion (CII) to transdermal fentanyl administration. The primary objective of the present study was to clarify the pharmacokinetic characteristics during this conversion. A secondary objective was to identify an association between serum albumin and the absorption of fentanyl from the transdermal patch.

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Oxidative stress is a critical mediator of various injuries following ischemia-reperfusion (I/R) associated with organ transplantation. Although oral bioavailability of cyclosporine A (CsA) was decreased by increased first-pass metabolism through CYP3A and P-glycoprotein (P-gp) specifically in the upper small intestine after liver I/R, the mechanism responsible for them remained to be clarified. In the present study, the effect of Trolox (an α-tocopherol analogue) on the decreased oral absorption of CsA through elevated intestinal CYP3A and P-gp after liver I/R and their regulations were investigated.

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We present a selective method for simultaneous determination of five polyether ionophores such as salinomycin (SAL), monensin (MON), narasin (NAR), semduramicin (SEM) and lasalocid (LAS) in aquatic samples using a liquid chromatography with one-step fluorescent derivatization of 2-(4-hydrazinocarbonyl-phenyl) 4,5-diphenylimidazole (HCPI) and 4-(4,5-diphenyl-1H-imidazol-2-yl) benzoyl chloride hydrochloride (DIB-Cl). Fluorescent one-step derivatization for SAL, MON, NAR and SEM using HCPI and for LAS using DIB-Cl was monitored by an LC/fluorescence detector (E(x), 340 nm; E(m), 465 nm). Chromatographic separation was performed on a TSK-GEL ODS-120T (4.

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Inhibition of angiotensin-converting enzyme (ACE) by various foods decreases the blood pressure. ACE inhibitors derived from natural components may be of therapeutic value in preventive medicine. In this study, we report a novel screening assay of ACE inhibitors from complex natural colourants and foods that employ solid phase extraction (SPE), high-throughput liquid chromatography (LC) separation, and stable isotope dilution electrospray tandem mass spectrometry (SID-ESI-MS/MS).

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We developed a useful and preparative method based on high-speed counter-current chromatography with mass spectrometry (HSCCC/MS) to purify gentamicin C1a, C2/2a and C1 from standard powder. The analytes were purified on the HSCCC model CCC-1000 (multi-layer coil planet centrifuge) with a volatile two-phase solvent system composed of n-butanol/10% aqueous ammonia solution (50:50, v/v) and detected on an LCMS-2020EV quadrupole mass spectrometer fitted with an electrospray ionization (ESI) source system in positive ionization following scan mode (m/z 100-500). The HSCCC/ESI-MS peaks indicated that gentamicin C1a (m/z 450: [M+H](+)), C2/2a (m/z 464: [M+H](+)) and C1 (m/z 478: [M+H](+)) have the peak resolution values of 1.

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We developed a high-throughput method based on on-line solid-phase extraction liquid chromatography tandem mass spectrometry (SPE-LC-MS/MS) to determine N-terminal thymosin-β fragment peptide (N-acetyl-seryl-aspartyl-lysyl-proline, Ac-SDKP) in human plasma samples. Quantification of Ac-SDKP was performed using direct injection for on-line SPE based on C(18), reversed-phase LC separation and stable isotope dilution electrospray ionization-MS/MS in multiple reaction-monitoring (MRM) mode. The Ac-SDKP-(13)C(6), (15)N(2) (m/z 496 → 137) was synthesized for the internal standard.

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We developed a sensitive, selective and accurate method based on liquid chromatography with tandem mass spectrometry (LC-MS/MS) to determine N-terminal thymosin-β peptides of Ac-SDKP and Ac-ADKP in human plasma samples. Quantification of Ac-SDKP and Ac-ADKP was performed using solid phase extraction (SPE) based on C(18), reversed phase LC separation, and stable isotope dilution electrospray ionization-MS/MS in multiple reaction-monitoring (MRM) mode. The Ac-SDKP-(13)C(6), (15)N(2) and Ac-ADKP-d(7) were synthesized for the internal standards.

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A method for the quantitation of nucleotides (adenosine 5'-monophosphate (AMP), guanosine 5'-monophosphate (GMP), uridine 5'-monophosphate (UMP), cytidine 5'-monophosphate (CMP), and inosine 5'-monophosphate (IMP)) in infant formula was developed by hydrophilic interaction chromatography with tandem mass spectrometry (HILIC-MS/MS). The internal standards used (AMP-13C10, 15N5; GMP-13C10, 15N5; UMP-13C9, 15N2; CMP-13C9, 15N3) were prepared with centrifugal ultrafiltration (CUF). Data acquisition was achieved by using multiple reaction monitoring (MRM) of product ions of protonated molecules of the five nucleotides generated by the positive-ion ESI.

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In the present study, a novel assay for screening inhibitors of Cu(II) ion/adrenaline-mediated oxidative modification of N-terminal amyloid beta (Abeta) peptides was developed using liquid chromatography with mass spectrometry (LC/MS). The physiological condition of Cu(II) ion/adrenaline in buffer (pH 7.4) at 37 degrees C for 90 min revealed a specific modification of N-terminal Abeta peptides, such as Abeta1-6, Abeta1-40, and Abeta1-42, using trypsin digestion and LC/MS detection of the modified Abeta peptide.

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An LC/ESI (positive-mode)-MS/MS method was developed for simultaneous quantification of 8 macrocyclic lactones (abamectin B1a, abamectin 8,9-Z isomer B1a, emamectin benzoate B1a, emamectin benzoate 8,9-Z isomer B1a, ivermectin, eprinomectin B1a, doramectin and moxidectin) in animal tissues, egg, milk and honey. The separation was achieved on a TSK-GEL ODS 100 V column (2.0 x 50 mm, 3 microm) with a mobile phase consisting of 0.

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In the field of pharmaceutical and biomedical analysis of peptides, a rapid on-line detection and identification for a methodology have been required for the discovery of new biological active products. In this study, a high-speed counter-current chromatography with electrospray mass spectrometry (HSCCC/ESI-MS) was developed for the on-line detection and purification of polypeptide antibiotics of enramycin-A and -B. The analytes were purified on HSCCC model CCC-1000 (multi-layer coil planet centrifuge) with a volatile solvent of two-phase system composed of n-butanol/hexane/0.

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We have developed a gas chromatography-mass spectrometry method to measure five phthalates (dibutyl phthalate, butylbenzyl phthalate, di-2-ethylhexyl phthalate, diisooctyl phthalate, and diisononyl phthalate) in diets and beddings for experimental animals. The recoveries from diets and beddings spiked with five phthalates were 98.8%-148% with coefficients of variation of 0.

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Analytical method for the simultaneous quantification of avermectins (AVMs), abamectin B1a, abamectin 8,9-Z isomer B1a, emamectine benzoate B1a, emamectine benzoate 8,9-Z isomer B1a, ivermectin, eprinomectin B1a, doramectin and moxidectin in bovine tissues (muscle, liver and fat) was developed by LC-MS/MS in electrospray positive ion mode. The separation was achieved on a short TSK-GEL ODS 100V column with the mobile phase consisting of acetonitrile and aquatic 0.1 mM ammonium formate containing 0.

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The authors previously developed a mobile ecological momentary assessment (EMA) system as a real-time data collection device using a mobile phone. In this study, a real-time advice function and real-time reporting function were added to the previous system as a supportive intervention. The improved system was found to work effectively and was applied to several clinical cases, including patients with depressive disorder, dizziness, smoking habit, and bronchial asthma.

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Production of microregional catalytic reactive oxygen species (ROS) by metal-binding amyloid-beta (Abeta) peptides mediates the neurotoxicity of Alzheimer's disease, and inhibitors of this activity may be of therapeutic value. No current analytical methods target specific ROS inhibitors produced by metal-binding peptides. We report a screening assay for metal-catalyzed oxidation (MCO) inhibitors based on liquid chromatography-mass spectrometry (LC-MS) with a model N-terminal Abeta peptide (Abeta(1-6)).

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