Publications by authors named "Yoshikazu Takahashi"

Real-time functional imaging of human neural activity and its closed-loop feedback enable voluntary control of targeted brain regions. In particular, a brain-computer interface (BCI), a direct bridge of neural activities and machine actuation is one promising clinical application of neurofeedback. Although a variety of studies reported successful self-regulation of motor cortical activities probed by scalp electroencephalogram (EEG), it remains unclear how neurophysiological, experimental conditions or BCI designs influence variability in BCI learning.

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Background: Little is known about the biweekly combined use of cetuximab and chemotherapy as second-line treatment of metastatic colorectal cancer (mCRC). Recently, DNA methylation status has been reported to be a new possible predictor of the efficacy from the anti-epidermal growth factor receptor (EGFR) antibody treatment. The purpose of this study was to examine the efficacy and safety of biweekly cetuximab plus mFOLFOX6 or mFOLFIRI as a second-line treatment for exon 2 wild-type mCRC.

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Background: There is no large real-world data regarding efficacy and safety of immunotherapy in gastric cancer (GC). Although some tumors can grow rapidly after immunotherapy, the patient proportions and survival outcomes are unclear in GC.

Methods: A multicenter, prospective observational study was performed to evaluate clinical outcomes including survival time, safety, and tumor behavior of nivolumab treatment for patients with advanced GC.

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Purpose: The current study aimed to determine the efficacy of trifluridine/tipiracil for elderly patients with advanced colorectal cancer.

Methods: This single-arm, open-label, multicenter, phase II study included elderly patients aged 65 years or more who had fluoropyrimidine-refractory advanced colorectal cancer and received trifluridine/tipiracil (70 mg/m, days 1-5 and 8-12, every 4 weeks). The primary endpoint was progression-free survival (PFS), while secondary endpoints included overall survival (OS), overall response rate (ORR), toxicities, association between efficacy and geriatric assessment scores, and association between toxicity and plasma drug concentrations.

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Article Synopsis
  • Mutations in a specific gene are linked to Parkinson's disease (PD) and affect the aggregation of α-synuclein, leading to degeneration of dopamine neurons.
  • Deficiency in this gene results in early neurotransmission defects and progressive cell loss in the brain, particularly impacting dopamine neurons due to altered phospholipid acyl-chain lengths.
  • Introducing wild-type proteins can reverse issues caused by the deficiency, while a disease-related mutant does not help; additionally, linoleic acid can mitigate the increased aggregation of α-synuclein caused by the deficiency, highlighting the importance of lipid composition in neuronal health.
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Purpose: The purpose of this research is to clarify the effects of low monitor unit (MU) on multileaf collimator (MLC) position accuracy and dose distribution in intensity modulated radiotherapy (IMRT) using respiratory gated.

Method: In the phantom experiment, irradiation without respiratory gated and respiratory gated with low MU (3, 5, and 7 MU) were performed, and positional accuracy and dose distribution of MLC were analyzed. MLC positional accuracy was calculated from the log-files and the MLC position error, gap size error, MLC leaf speed were calculated and compared with the planned value.

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Background: Recombinant human soluble thrombomodulin (rTM) has been established and introduced in the clinic as a standard treatment for disseminated intravascular coagulation (DIC). However, the efficacy and safety of rTM for DIC associated with solid tumors (DIC-STs) have not been fully established. Here, we performed a retrospective analysis of the clinical outcomes of rTM for DIC-STs and considered a treatment strategy with rTM for DIC-STs.

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Docosahexaenoic acid (DHA) has essential roles in photoreceptor cells in the retina and is therefore crucial to healthy vision. Although the influence of dietary DHA on visual acuity is well known and the retina has an abundance of DHA-containing phospholipids (PL-DHA), the mechanisms associated with DHA's effects on visual function are unknown. We previously identified lysophosphatidic acid acyltransferase 3 (LPAAT3) as a PL-DHA biosynthetic enzyme.

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Neuropathic pain resulting from peripheral neuronal damage is largely resistant to treatment with currently available analgesic drugs. Recently, ATP, lysophosphatidic acid, and platelet-activating factor (PAF) have been reported to play important inductive roles in neuropathic pain. In the present study, we found that pain-like behaviors resulting from partial sciatic nerve ligation (PSL) were largely attenuated by deficiency of lysophosphatidylcholine acyltransferase (LPCAT)2, which is one of the PAF biosynthetic enzymes.

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In the course of screening for an inhibitor of farnesyl transferase (FTase), we identified two compounds, N-benzyl-aclacinomycin A (ACM) and N-allyl-ACM, which are new derivatives of ACM. N-benzyl-ACM and N-allyl-ACM inhibited FTase activity with IC50 values of 0.86 and 2.

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Novel block copolymers using the monomers 5-(2-methoxyethyoxymethyl)-5-methyl-[1,3]-dioxa-2-one (TMCM-MOE1OM) as a hydrophilic segment and lactides as a hydrophobic segment were designed in order to prepare controllable degradation polymers by dynamic polymer rearrangement based on the hydrophilicity. When the copolymer film contacted water, the hydrophobic polylactide (PLA) segments tend to be buried under the TMCM-MOE1OM segments due to the hydrophilicity of the methoxyethoxy groups. The copolymers were hardly degraded by both proteinase K and lipase, while both of their homopolymers, poly(trimethylene carbonate) and PLA, were degraded, which suggests that the rearrangement of the TMCM-MOE1OM segments at the outermost surface significantly improved the degradation ratio.

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Five human 2,3-oxidosqualnene cyclase (OSC) inhibitors were discovered using the combination of a virtual screening based on a docking study and an isotope-free assay system. All of these inhibitors were revealed to have activities comparable or superior to that of LDAO, a known OSC inhibitor. The computational study of the newly identified inhibitors suggested that CH/π interactions with F444 and W581 contribute to the binding, and these interactions are candidates for additional structural filters in the next generation of virtual screening.

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The purpose of this study was to compare the effectiveness of dental checkups incorporating tooth-brushing instruction (TBI) with that of conventional dental checkups. A team consisting of one dentist and three dental hygienists saw an average of 60 employees per day on-site at an airline company. The patient's teeth were stained with a disclosing tablet and the results recorded on a Plaque Control Record (PCR) chart.

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Three new stilbene derivatives, albiraminols A (1) (resveratrol hexamer), B (2) (resveratrol dimer), and vatalbinoside F (3) (mono-glucoside of resveratrol dimer), along with malibatol were isolated from acetone soluble portions of the stem of Vatica albiramis. The structures of the isolates were established on the basis of spectroscopic analyses, including a detailed NMR spectroscopic investigation. The biosynthetic aspects of the isolates are discussed in this paper.

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Investigation of the highly polar chemical constituents in the stem of Hopea parviflora (Dipterocarpaceae) resulted in the isolation of four new resveratrol derivatives, hopeasides A and B (1, 2) (resveratrol pentamers), C (3) (resveratrol trimer), and D (4) (resveratrol dimer) together with nine known resveratrol oligomers (5-13). The new structures have a common partial structure of the 1-hydroxy-1-(3,5-dihydroxy-2-C-glucopyranosylphenyl)-2-(4-hydroxyphenyl)ethane-2-yl group after oxidative condensation of (E)-resveratrol-10-C-β-glucopyranoside (14). The structures were determined by spectroscopic analysis including 2D-NMR and computer-aided molecular modeling.

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The first total synthesis of incednam (1), the aglycon of antibiotic incednine (2), is described. Incednine has been reported to exhibit significant inhibitory activity against the antiapoptotic oncoproteins Bcl-2 and Bcl-xL. The synthesis of 1 commenced with the preparation of the C1-C13 subunit 3 and the C14-C23 subunit 4.

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Comprehensive re-investigation of the chemical constituents in the leaves of Vateria indica (Dipterocarpaceae) resulted in the isolation of a novel resveratrol dimeric dimer having a C(2)-symmetric structure, vateriaphenol F (1), and two new O-glucosides of resveratrol oligomers, vateriosides A (2) (resveratrol dimer) and B (4) (resveratrol tetramer), along with a new natural compound (3) and 33 known compounds including 26 resveratrol derivatives. The absolute structures were elucidated by spectroscopic analysis, including two dimensional NMR and circular dichroism (CD) spectra.

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In the course of screening for a new type of androgen receptor (AR) antagonist, we isolated a novel compound, arabilin, with two structural isomers, spectinabilin and SNF4435C, produced by Streptomyces sp. MK756-CF1. Structure elucidation on the basis of the spectroscopic properties showed that arabilin is a novel polypropionate-derived metabolite with a p-nitrophenyl group and a substituted γ-pyrone ring.

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A synthetic route to paleic acid 1, antimicrobial agent effective against Mannheimia haemolytica and Pasteurella multocida, has been established. The absolute configuration of the secondary hydroxyl group was controlled by a catalytic asymmetric alkylation of an aldehyde using a chiral titanium sulfonamide complex and the cis double bond was installed using a Wittig reaction. This synthetic route was also applied to the preparation of structurally related analogs, which were used in structure-activity relationship studies for antibacterial activity.

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Pyrrole- and 1,2,3-triazole-based 2,3-oxidosqualene cyclase (OSC) inhibitors 3 and 4 were discovered by conducting a virtual screening, a docking study based on the crystallographic structure of OSC, and biological assays. The hit rate of the assays was increased by establishing appropriate substructural filters in the virtual screening stage. Amide derivatives of 8 and 12 preserved the inhibitory activity of parent compound 3, which provided a reasonable starting point for further structure-activity-relationship (SAR) studies on related compounds.

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The structure-activity relationship of the boronic acid derivatives of tyropeptin, a proteasome inhibitor, was studied. Based on the structure of a previously reported boronate analog of tyropeptin (2), 41 derivatives, which have varying substructure at the N-terminal acyl moiety and P2 position, were synthesized. Among them, 3-phenoxyphenylacetamide 6 and 3-fluoro picolinamide 22 displayed the most potent inhibitory activity toward chymotryptic activity of proteasome and cytotoxicity, respectively.

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Paleic acid (1), an antibiotic, was obtained from a fermentation broth of Paenibacillus sp. BMK771-AF3. The compound is a fatty acid (9Z,16R)-16-hydroxy-9-octadecenoic acid ((R)-16-hydroxyoleic acid), whose isolation required protection of its polar functional groups.

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