6,555 results on '"Yamasaki, A"'
Search Results
2. Tunable Plasmon Resonance in Silver Nanodisk-on-Mirror Structures and Scattering Enhancement by Annealing
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Ryohei Hatsuoka, Kota Yamasaki, Kenji Wada, Tetsuya Matsuyama, and Koichi Okamoto
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plasmonics ,metamaterials ,localized surface plasmon resonance ,Chemistry ,QD1-999 - Abstract
In this study, we evaluated the surface plasmon characteristics of periodic silver nanodisk structures fabricated on a dielectric thin-film spacer layer on a Ag mirror substrate (NanoDisk on Mirror: NDoM) through finite difference time domain (FDTD) simulations and experiments involving actual sample fabrication. Through FDTD simulations, it was confirmed that the NDoM structure exhibits two sharp peaks in the visible range, and by adjusting the thickness of the spacer layer and the size of the nanodisk structure, sharp peaks can be obtained across the entire visible range. Additionally, we fabricated the NDoM structure using electron beam lithography (EBL) and experimentally confirmed that the obtained peaks matched the simulation results. Furthermore, we discovered that applying annealing at an appropriate temperature to the fabricated structure enables the adjustment of the resonance peak wavelength and enhances the scattering intensity by approximately five times. This enhancement is believed to result from changes in the shape and size of the nanodisk structure, as well as a reduction in grain boundaries in the metal crystal due to annealing. These results have the potential to contribute to technological advancements in various application fields, such as optical sensing and emission enhancement.
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- 2024
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3. Verification of the Solid–Liquid Separation of Waterlogged Reduced Soil via a Centrifugal Filtration Method
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Shatabdi Saha, Kumi Watanabe, Tomoyuki Makino, Hitoshi Kanno, Kazuhiko Kimura, and Shin-Ichi Yamasaki
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soil properties ,soil solution ,suction method ,soil redox potential ,solute concentrations ,reductive conditions ,Physical geography ,GB3-5030 ,Chemistry ,QD1-999 - Abstract
The efficient separation of solid and liquid phases of soil under reductive conditions is of the utmost importance to study soil chemistry and to predict the mobility and bioavailability of nutrients and toxic contaminants in waterlogged reduced soils (WRSs). However, there is no established method for efficiently separating the solid and liquid phases of WRS within a short time while maintaining its reductive conditions. This study aimed to verify the applicability of a simple centrifugal filtration method (CFM) for the efficient separation of solid and liquid phases of a WRS and examine the CFM-extracted soil solution to confirm that the reductive condition was maintained during the solid–liquid separation process. Incubation experiments were performed under reductive conditions with or without ethanol/molasses used as additional organic material (OM), while the soil solution was collected by both a suction method and CFM at different centrifugation speeds (700, 2760, and 11,000 rpm) and times (1–7 min). The results showed that the soil pH increased with time while the Eh decreased, indicating that its reducing state was enhanced during the incubation experiments. The addition of OM promoted the reductive conditions in the first days of the experiments. Centrifugation speed, rather than time, was found to be the key to extract the maximum amount of soil solution, while a higher centrifugation speed (11,000 rpm), which represents the permanent wilting point, was found to be most effective for extracting the maximum amount of soil solution. The results exhibited no significant difference in solute (As, Fe(II), and Mn) concentrations when varying amounts of CFM-extracted soil solution were measured. The statistical analysis also indicated no significant (p > 0.05) difference between the solute concentrations in the CFM-extracted soil solution and the solute concentrations in the soil solution extracted by the suction method, confirming that the reductive condition was maintained during solid–liquid separation by CFM. This study suggests that CFM operating at a higher centrifugation speed could potentially be employed as a simple and highly effective technique to efficiently separate the solid and liquid phases of WRS (sandy clay loam) within a short time while maintaining its reductive conditions.
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- 2024
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4. Removal of Borate Ions from Wastewater Using an Adsorbent Prepared from Waste Concrete (PAdeCS)
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Tsubasa Shimizu, Masahiro Abe, Miyuki Noguchi, and Akihiro Yamasaki
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Chemistry ,QD1-999 - Published
- 2022
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5. Chlorine Atoms of an Aripiprazole Molecule Control the Geometry and Motion of Aripiprazole and Deschloro-aripiprazole in Subdomain IIIA of Human Serum Albumin
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Akito Kawai, Yoshihiro Kobashigawa, Kenshiro Hirata, Hiroshi Morioka, Shuhei Imoto, Koji Nishi, Victor Tuan Giam Chuang, Keishi Yamasaki, and Masaki Otagiri
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Chemistry ,QD1-999 - Published
- 2022
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6. Preparation of High-Purity Calcium Carbonate by Mineral Carbonation Using Concrete Sludge
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Shunsuke Tanaka, Kosuke Takahashi, Masahiro Abe, Miyuki Noguchi, and Akihiro Yamasaki
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Chemistry ,QD1-999 - Published
- 2022
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7. Intracranial Gene Delivery Mediated by Albumin-Based Nanobubbles and Low-Frequency Ultrasound
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Takayuki Koga, Hiroshi Kida, Yutaro Yamasaki, Loreto B. Feril, Hitomi Endo, Keiji Itaka, Hiroshi Abe, and Katsuro Tachibana
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nanobubble ,low-frequency ultrasound ,drug delivery system ,central nervous system ,Chemistry ,QD1-999 - Abstract
Research in the field of high-intensity focused ultrasound (HIFU) for intracranial gene therapy has greatly progressed over the years. However, limitations of conventional HIFU still remain. That is, genes are required to cross the blood-brain barrier (BBB) in order to reach the neurological disordered lesion. In this study, we introduce a novel direct intracranial gene delivery method, bypassing the BBB using human serum albumin-based nanobubbles (NBs) injected through a less invasive intrathecal route via lumbar puncture, followed by intracranial irradiation with low-frequency ultrasound (LoFreqUS). Focusing on both plasmid DNA (pDNA) and messenger RNA (mRNA), our approach utilizes LoFreqUS for deeper tissue acoustic penetration and enhancing gene transfer efficiency. This drug delivery method could be dubbed as the “Spinal Back-Door Approach”, an alternative to the “front door” BBB opening method. Experiments showed that NBs effectively responded to LoFreqUS, significantly improving gene transfer in vitro using U-87 MG cell lines. In vivo experiments in mice demonstrated significantly increased gene expression with pDNA; however, we were unable to obtain conclusive results using mRNA. This novel technique, combining albumin-based NBs and LoFreqUS offers a promising, efficient, targeted, and non-invasive solution for central nervous system gene therapy, potentially transforming the treatment landscape for neurological disorders.
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- 2024
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8. Phosphorus-Alloying as a Powerful Method for Designing Highly Active and Durable Metal Nanoparticle Catalysts for the Deoxygenation of Sulfoxides: Ligand and Ensemble Effects of Phosphorus
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Hiroya Ishikawa, Sho Yamaguchi, Ayako Nakata, Kiyotaka Nakajima, Seiji Yamazoe, Jun Yamasaki, Tomoo Mizugaki, and Takato Mitsudome
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Chemistry ,QD1-999 - Published
- 2022
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9. Effects of Myristate on the Induced Circular Dichroism Spectra of Aripiprazole Bound to Human Serum Albumin: A Structural–Chemical Investigation
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Kenshiro Hirata, Akito Kawai, Victor Tuan Giam Chuang, Keiki Sakurama, Koji Nishi, Keishi Yamasaki, and Masaki Otagiri
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Chemistry ,QD1-999 - Published
- 2022
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10. Generation of Tetrafluoroethylene–Propylene Elastomer-Based Microfluidic Devices for Drug Toxicity and Metabolism Studies
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Emi Sano, Sayaka Deguchi, Naoki Matsuoka, Masahiro Tsuda, Mengyang Wang, Kaori Kosugi, Chihiro Mori, Keisuke Yagi, Aya Wada, Shinsuke Yamasaki, Tsuyoshi Kawai, Masahide Yodogawa, Hiroyuki Mizuguchi, Norihito Nakazawa, Fumiyoshi Yamashita, Yu-suke Torisawa, and Kazuo Takayama
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Chemistry ,QD1-999 - Published
- 2021
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11. Investigation of Mineral Carbonation with Direct Bubbling into Concrete Sludge
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Masahiro Abe, Shunsuke Tanaka, Miyuki Noguchi, and Akihiro Yamasaki
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Chemistry ,QD1-999 - Published
- 2021
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12. The Effect of Cysteine Peptide Ingestion on Skin Brightness, a Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Human Clinical Trial
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Yoshiaki Uchida, Tomomi Kaneda, Mio Ono, Masao Matsuoka, Utano Nakamura, Akiko Ishida, Yoshimitsu Yamasaki, Hiroki Takeo, and Takanobu Sakurai
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cysteine peptide ,glutathione ,cysteinylglycine ,γ-glutamylcysteine ,skin brightness ,safety ,Chemistry ,QD1-999 - Abstract
Glutathione (GSH) is present in almost all human cells and has a beneficial effect on human skin brightness. Cysteinylglycine (Cys-Gly) and γ-glutamylcysteine (γ-Glu-Cys) are GSH synthesis components. In this study, we defined glutathione (GSH), cysteinylglycine (Cys-Gly), and γ-glutamylcysteine (γ-Glu-Cys) as cysteine peptide and performed a randomized, double-blind, placebo-controlled study to investigate the effects of orally administered cysteine peptide on human skin brightness using a CM-26d portable spectrophotometer in healthy males and females aged between 20 and 65 years old. Eligible participants were randomly allocated into three groups (cysteine peptide 45 mg: n = 16, 90 mg: n = 15, and placebo: n = 16). Each subject ingested six tablets every day for 12 weeks, and skin brightness was measured at 0, 4, 8, and 12 weeks. As a result, the 45 mg group exhibited arm brightening in a time-dependent manner, and a significant difference was observed compared to the placebo at week 12 (p = 0.028). Moreover, no serious adverse events and changes related to 270 mg study food were observed in the safety trial. Here, we suggest that cysteine peptide is a promising and safe compound for human skin brightness.
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- 2023
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13. Single-Crystal Cobalt Phosphide Nanorods as a High-Performance Catalyst for Reductive Amination of Carbonyl Compounds
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Min Sheng, Shu Fujita, Sho Yamaguchi, Jun Yamasaki, Kiyotaka Nakajima, Seiji Yamazoe, Tomoo Mizugaki, and Takato Mitsudome
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Chemistry ,QD1-999 - Published
- 2021
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14. Efficient mRNA Delivery with Lyophilized Human Serum Albumin-Based Nanobubbles
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Hiroshi Kida, Yutaro Yamasaki, Loreto B. Feril Jr., Hitomi Endo, Keiji Itaka, and Katsuro Tachibana
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nanobubble ,lyophilization ,sonoporation ,mRNA ,drug delivery system ,ultrasound ,Chemistry ,QD1-999 - Abstract
In this study, we developed an efficient mRNA delivery vehicle by optimizing a lyophilization method for preserving human serum albumin-based nanobubbles (HSA-NBs), bypassing the need for artificial stabilizers. The morphology of the lyophilized material was verified using scanning electron microscopy, and the concentration, size, and mass of regenerated HSA-NBs were verified using flow cytometry, nanoparticle tracking analysis, and resonance mass measurements, and compared to those before lyophilization. The study also evaluated the response of HSA-NBs to 1 MHz ultrasound irradiation and their ultrasound (US) contrast effect. The functionality of the regenerated HSA-NBs was confirmed by an increased expression of intracellularly transferred Gluc mRNA, with increasing intensity of US irradiation. The results indicated that HSA-NBs retained their structural and functional integrity markedly, post-lyophilization. These findings support the potential of lyophilized HSA-NBs, as efficient imaging, and drug delivery systems for various medical applications.
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- 2023
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15. Magnesium Hydroxide Nanoparticles Inhibit the Biofilm Formation of Cariogenic Microorganisms
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Kentaro Okamoto, Daisuke Kudo, Dao Nguyen Duy Phuong, Yoshihito Iwamoto, Koji Watanabe, Yoshie Yoshioka, Wataru Ariyoshi, and Ryota Yamasaki
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magnesium hydroxide nanoparticles ,dental caries ,cariogenic microorganisms ,biofilm inhibition ,Chemistry ,QD1-999 - Abstract
Although various caries-preventive agents have been developed, dental caries is still a leading global disease, mostly caused by biological factors such as mutans streptococci. Magnesium hydroxide nanoparticles have been reported to exhibit antibacterial effects; however, they are rarely used in oral care practical applications. In this study, we examined the inhibitory effect of magnesium hydroxide nanoparticles on biofilm formation by Streptococcus mutans and Streptococcus sobrinus—two typical caries-causing bacteria. Three different sizes of magnesium hydroxide nanoparticles (NM80, NM300, and NM700) were studied, all of which inhibited biofilm formation. The results showed that the nanoparticles were important for the inhibitory effect, which was not influenced by pH or the presence of magnesium ions. We also determined that the inhibition process was mainly contact inhibition and that medium (NM300) and large (NM700) sizes were particularly effective in this regard. The findings of our study demonstrate the potential applications of magnesium hydroxide nanoparticles as caries-preventive agents.
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- 2023
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16. Preparation, Characterization, and in Vitro/in Vivo Evaluation of Paclitaxel-Bound Albumin-Encapsulated Liposomes for the Treatment of Pancreatic Cancer
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Yuko Okamoto, Kazuaki Taguchi, Mina Sakuragi, Shuhei Imoto, Keishi Yamasaki, and Masaki Otagiri
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Chemistry ,QD1-999 - Published
- 2019
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17. Effects of an Adapted Sports Intervention on Elderly Women in Need of Long-Term Care: A Pilot Study
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Takashi Kawano, Goro Moriki, Shinya Bono, Junya Masumoto, Nobuyuki Kaji, Hungu Jung, and Masahiro Yamasaki
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adapted sport ,elderly women ,need of long-term care ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
This study aimed to evaluate the effects of an adapted sports intervention on elderly women in need of long-term care (NLTC). Although participation in sports activities positively impacts subjective health status, few studies have evaluated the safety, comfort, and effectiveness of competitive sports in elderly women in NLTC. In this study, ten elderly women in NLTC (age: 80.6 ± 8.2 years) were asked to participate in boccia, a sport adapted to prevent falls. Participants completed the Profile of Mood States 2nd Edition Short-Form and the Medical Outcome Study 36-Item Short-Form Health Survey Version 2. The results showed an improvement in mood states (anger–hostility, tension–anxiety, and total mood disturbance) of elderly women in the NLTC group compared with the control group. Therefore, boccia, an adapted sport, can be considered a safe and competitive option for such women.
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- 2022
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18. Analysis of the Binding of Aripiprazole to Human Serum Albumin: The Importance of a Chloro-Group in the Chemical Structure
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Keiki Sakurama, Akito Kawai, Victor Tuan Giam Chuang, Yoko Kanamori, Miyu Osa, Kazuaki Taguchi, Hakaru Seo, Toru Maruyama, Shuhei Imoto, Keishi Yamasaki, and Masaki Otagiri
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Chemistry ,QD1-999 - Published
- 2018
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19. Frost flowers and sea-salt aerosols over seasonal sea-ice areas in northwestern Greenland during winter–spring
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K. Hara, S. Matoba, M. Hirabayashi, and T. Yamasaki
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Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Sea salts and halogens in aerosols, frost flowers, and brine play an important role in atmospheric chemistry in polar regions. Simultaneous sampling and observations of frost flowers, brine, and aerosol particles were conducted around Siorapaluk in northwestern Greenland during December 2013 to March 2014. Results show that water-soluble frost flower and brine components are sea-salt components (e.g., Na+, Cl−, Mg2+, K+, Ca2+, Br−, and iodine). Concentration factors of sea-salt components of frost flowers and brine relative to seawater were 1.14–3.67. Sea-salt enrichment of Mg2+, K+, Ca2+, and halogens (Cl−, Br−, and iodine) in frost flowers is associated with sea-salt fractionation by precipitation of mirabilite and hydrohalite. High aerosol number concentrations correspond to the occurrence of higher abundance of sea-salt particles in both coarse and fine modes, and blowing snow and strong winds. Aerosol number concentrations, particularly in coarse mode, are increased considerably by release from the sea-ice surface under strong wind conditions. Sulfate depletion by sea-salt fractionation was found to be limited in sea-salt aerosols because of the presence of non-sea-salt (NSS) SO42−. However, coarse and fine sea-salt particles were found to be rich in Mg. Strong Mg enrichment might be more likely to proceed in fine sea-salt particles. Magnesium-rich sea-salt particles might be released from the surface of snow and slush layer (brine) on sea ice and frost flowers. Mirabilite-like and ikaite-like particles were identified only in aerosol samples collected near new sea-ice areas. From the field evidence and results from earlier studies, we propose and describe sea-salt cycles in seasonal sea-ice areas.
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- 2017
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20. Nanocellulose Xerogels With High Porosities and Large Specific Surface Areas
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Shunsuke Yamasaki, Wataru Sakuma, Hiroaki Yasui, Kazuho Daicho, Tsuguyuki Saito, Shuji Fujisawa, Akira Isogai, and Kazuyoshi Kanamori
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cellulose nanofiber ,xerogel ,aerogel ,porous material ,ambient pressure drying ,Chemistry ,QD1-999 - Abstract
Xerogels are defined as porous structures that are obtained by evaporative drying of wet gels. One challenge is producing xerogels with high porosity and large specific surface areas, which are structurally comparable to supercritical-dried aerogels. Herein, we report on cellulose xerogels with a truly aerogel-like porous structure. These xerogels have a monolithic form with porosities and specific surface areas in the ranges of 71–76% and 340–411 m2/g, respectively. Our strategy is based on combining three concepts: (1) the use of a very fine type of cellulose nanofibers (CNFs) with a width of ~3 nm as the skeletal component of the xerogel; (2) increasing the stiffness of wet CNF gels by reinforcing the inter-CNF interactions to sustain their dry shrinkage; and (3) solvent-exchange of wet gels with low-polarity solvents, such as hexane and pentane, to reduce the capillary force on drying. The synergistic effects of combining these approaches lead to improvements in the porous structure in the CNF xerogels.
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- 2019
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21. Magnesium Hydroxide Nanoparticles Kill Exponentially Growing and Persister Escherichia coli Cells by Causing Physical Damage
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Yohei Nakamura, Kaede Okita, Daisuke Kudo, Dao Nguyen Duy Phuong, Yoshihito Iwamoto, Yoshie Yoshioka, Wataru Ariyoshi, and Ryota Yamasaki
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magnesium hydroxide nanoparticle ,Escherichia coli ,sterilization ,persister ,Chemistry ,QD1-999 - Abstract
Magnesium hydroxide nanoparticles are widely used in medicinal and hygiene products because of their low toxicity, environment-friendliness, and low cost. Here, we studied the effects of three different sizes of magnesium hydroxide nanoparticles on antibacterial activity: NM80, NM300, and NM700. NM80 (D50 = 75.2 nm) showed a higher bactericidal effect against Escherichia coli than larger nanoparticles (D50 = 328 nm (NM300) or 726 nm (NM700)). Moreover, NM80 showed a high bactericidal effect against not only exponential cells but also persister cells, which are difficult to eliminate owing to their high tolerance to antibiotics. NM80 eliminated strains in which magnesium-transport genes were knocked out and exhibited a bactericidal effect similar to that observed in the wild-type strain. The bactericidal action involved physical cell damage, as confirmed using scanning electron microscopy, which showed that E. coli cells treated with NM80 were directly injured.
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- 2021
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22. Clinical Benefits of Hepatic Arterial Infusion Chemotherapy for Advanced Hepatocellular Carcinoma
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Takahiro Yamasaki, Issei Saeki, Yurika Kotoh-Yamauchi, Ryo Sasaki, Norikazu Tanabe, Takashi Oono, Takashi Matsuda, Takuro Hisanaga, Toshihiko Matsumoto, Isao Hidaka, Tsuyoshi Ishikawa, Taro Takami, Yutaka Suehiro, and Isao Sakaida
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advanced hepatocellular carcinoma ,hepatic arterial infusion chemotherapy ,sorafenib ,vascular invasion ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Recent success of systemic therapeutic agents, including combination immunotherapy, could promote a change in the treatment strategy in patients with advanced hepatocellular carcinoma (HCC). Although hepatic arterial infusion chemotherapy (HAIC) is a treatment option for advanced HCC in Japan, it is not recommended by other guidelines. We discuss the clinical benefits of HAIC compared to sorafenib. The clinical benefits of HAIC are as follows: (1) even a patient with Child–Pugh B HCC (7 or 8 points) is a candidate for HAIC (2) Child–Pugh scores barely decline with the use of HAIC compared with sorafenib (3) HAIC is highly effective in patients with vascular invasion compared with sorafenib; and (4) survival in patients receiving HAIC may not be associated with skeletal muscle volume. In contrast, the disadvantages are problems related with the reservoir system. HAIC has clinical benefits in a subpopulation of patients without extrahepatic metastasis with Child–Pugh A HCC and vascular invasion (especially primary branch invasion or main portal vein invasion) or with Child–Pugh B HCC.
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- 2021
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23. Magneto-Structural Relationship of Tetragonally-Compressed Octahedral Iron(II) Complex Surrounded by a pseudo-S6 Symmetric Hexakis-Dimethylsulfoxide Environment
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Hiroshi Sakiyama, Takaaki Abiko, Masayuki Koikawa, and Mikio Yamasaki
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octahedral high-spin iron(II) complex ,crystal structure ,magnetic properties ,density functional theory ,magneto-structural relationship ,Chemistry ,QD1-999 - Abstract
Since the octahedral high-spin iron(II) complex has the 5T2g ground term, the spin-orbit coupling should be considered in magnetic analysis; however, such treatment is rarely seen in recent papers, although the symmetry-sensitive property is of interest to investigate in detail. A method to consider the T-term magnetism was well constructed more than half a century ago. On the other hand, the method has been still improved in recent years. In this study, the octahedral high-spin iron(II) complex [Fe(dmso)6][BPh4]2 (dmso: dimethylsulfoxide) was newly prepared, and the single-crystal X-ray diffraction method revealed the tetragonal compression of the D4-symmetric coordination geometry around the iron(II) ion and the pseudo-S6 hexakis-dmso environment. From the magnetic data, the sign of the axial splitting parameter, Δ, was found to be negative, indicating the 5E ground state in the D4 symmetry. The DFT computation showed the electronic configuration of (dxz)2(dx2−y2)1(dyz)1(dxy)1(dz2)1 due to the tetragonal compression and the pseudo-S6 environment of dmso π orbitals. The electronic configuration corresponded to the 5E ground term, which was in agreement with the negative Δ value. Therefore, the structurally predicted ground state was consistent with the estimation from the magnetic measurements.
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- 2021
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24. Redox Monitoring in Nuclear Medical Imaging
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Toshihide Yamasaki, Kohei Sano, and Takahiro Mukai
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Diagnostic Imaging ,Antioxidant ,Physiology ,medicine.medical_treatment ,Radical ,Clinical Biochemistry ,Oxidative phosphorylation ,medicine.disease_cause ,Biochemistry ,Redox ,Antioxidants ,chemistry.chemical_compound ,In vivo ,medicine ,Molecular Biology ,General Environmental Science ,chemistry.chemical_classification ,Reactive oxygen species ,Cell Biology ,Glutathione ,Cell biology ,Oxidative Stress ,chemistry ,General Earth and Planetary Sciences ,Reactive Oxygen Species ,Oxidation-Reduction ,Oxidative stress - Abstract
SIGNIFICANCE The imbalance in redox homeostasis is known as oxidative stress, which is relevant to many diseases such as cancer, arteriosclerosis, and neurodegenerative disorders. Overproduction of reactive oxygen species (ROS) is one of the factors that trigger the redox state imbalance in vivo. ROS have high reactivity and impair biomolecules, while antioxidants and antioxidant enzymes, such as ascorbate and glutathione, reduce the overproduction of ROS to rectify the redox imbalance. Owing to this, redox monitoring tools have been developed to understand the redox fluctuations in oxidative stress-related diseases. Recent Advances: In an attempt to monitor redox substances, including ROS and radical species, versatile modalities have been developed, such as electron spin resonance, chemiluminescence, and fluorescence. In particular, many fluorescent probes have been developed that are selective for ROS. This has significantly contributed to understanding the relevance of ROS in disease onset and progression. CRITICAL ISSUES To date, the dynamics of ROS and radical fluctuation in in vivo redox states remain unclear, and there are few methods for the in vivo detection of redox fluctuations. FUTURE DIRECTIONS In this review, we summarize the development of radiolabeled probes for monitoring redox-relevant species by nuclear medical imaging that is applicable in vivo. In the future, translational research is likely to be advanced through the development of highly sensitive and in vivo applicable detection methods, such as nuclear medical imaging, to clarify the underlying dynamics of ROS, radicals, and redox substances in many diseases.
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- 2022
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25. Deficiency of MTH1 and/or OGG1 increases the accumulation of 8-oxoguanine in the brain of the AppNL-G-F/NL-G-F knock-in mouse model of Alzheimer’s disease, accompanied by accelerated microgliosis and reduced anxiety-like behavior
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Takaomi C. Saido, Takashi Saito, Nona Abolhassani, Yusaku Nakabeppu, Y Mizuno, Jun-ichi Kira, Ryo Yamasaki, and Guianfranco Mazzei
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medicine.medical_specialty ,Chemistry ,General Neuroscience ,General Medicine ,Microgliosis ,medicine.disease_cause ,Amygdala ,8-Oxoguanine ,Cortex (botany) ,Pathogenesis ,chemistry.chemical_compound ,Endocrinology ,medicine.anatomical_structure ,DNA glycosylase ,Internal medicine ,medicine ,Triphosphatase ,Oxidative stress - Abstract
Oxidative stress is a major risk factor for Alzheimer's disease (AD). Among various oxidized molecules, the marked accumulation of an oxidized form of guanine, 8-oxo-7,8-dihydroguanine (8-oxoG), is observed in the AD brain. 8-oxo-2´-deoxyguanosine triphosphatase (MTH1) and 8-oxoG DNA glycosylase (OGG1) minimize the 8-oxoG accumulation in DNA, and their expression is decreased in the AD brain. MTH1 and/or OGG1 may suppress the pathogenesis of AD; however, their exact roles remain unclear. We evaluated the roles of MTH1 and OGG1 during the pathogenesis of AD using AppNL-G-F/NL-G-F knock-in mice (a preclinical AD model). Six-month-old female AppNL-G-F/NL-G-F mice with MTH1 and/or OGG1 deficiency exhibited reduced anxiety-related behavior, but their cognitive and locomotive functions were unchanged; the alteration was less evident in 12-month-old mice. MTH1 and/or OGG1 deficiency accelerated the 8-oxoG accumulation and microgliosis in the amygdala and cortex of six-month-old mice; the alteration was less evident in 12-month-old mice. Astrocytes and neurons were not influenced. We showed that MTH1 and OGG1 are essential for minimizing oxidative DNA damage in the AppNL-G-F/NL-G-F brain, and the effects are age-dependent. MTH1 and/or OGG1 deficiency reduced anxiety-related behavior in AppNL-G-F/NL-G-F mice with a significant acceleration of the 8-oxoG burden and microgliosis, especially in the cortex and amygdala.
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- 2022
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26. Activation of Extrasynaptic Kainate Receptors Drives Hilar Mossy Cell Activity
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Kenji Sakimura, Ramos Cc, Pablo E. Castillo, Miwako Yamasaki, Stefano Lutzu, Yuchio Yanagawa, Masahiko Watanabe, and Susumu Tomita
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Mossy fiber (hippocampus) ,Kainic acid ,Kainic Acid ,Chemistry ,Dentate gyrus ,Pyramidal Cells ,General Neuroscience ,Glutamate receptor ,Hippocampus ,Glutamic Acid ,Kainate receptor ,Neurotransmission ,Hippocampal formation ,humanities ,chemistry.chemical_compound ,Mice ,Receptors, Kainic Acid ,Mossy Fibers, Hippocampal ,Synapses ,Animals ,Neuroscience ,Research Articles - Abstract
Mossy cells (MCs) of the dentate gyrus (DG) are key components of an excitatory associative circuit established by reciprocal connections with dentate granule cells (GCs). MCs are implicated in place field encoding, pattern separation and novelty detection, as well as in brain disorders such as temporal lobe epilepsy and depression. Despite their functional relevance, little is known about the determinants that control MC activity. Here, we examined whether MCs express functional kainate receptors (KARs), a subtype of glutamate receptors involved in neuronal development, synaptic transmission and epilepsy. Using mouse hippocampal slices, we found that bath application of submicromolar and micromolar concentrations of the KAR agonist kainic acid induced inward currents and robust MC firing. These effects were abolished in GluK2 KO mice, indicating the presence of functional GluK2-containing KARs in MCs. In contrast to CA3 pyramidal cells, which are structurally and functionally similar to MCs, and express synaptic KARs at mossy fiber (MF) inputs (i.e., GC axons), we found no evidence for KAR-mediated transmission at MF-MC synapses, indicating that most KARs at MCs are extrasynaptic. Immunofluorescence and immunoelectron microscopy analyses confirmed the extrasynaptic localization of GluK2-containing KARs in MCs. Finally, blocking glutamate transporters, a manipulation that increases extracellular levels of endogenous glutamate, was sufficient to induce KAR-mediated inward currents in MCs, suggesting that MC-KARs can be activated by increases in ambient glutamate. Our findings provide the first direct evidence of functional extrasynaptic KARs at a critical excitatory neuron of the hippocampus.Significance StatementHilar mossy cells (MCs) are an understudied population of hippocampal neurons that form an excitatory loop with dentate granule cells. MCs have been implicated in pattern separation, spatial navigation, and epilepsy. Despite their importance in hippocampal function and disease, little is known about how MC activity is recruited. Here, we show for the first time that MCs express extrasynaptic kainate receptors (KARs), a subtype of glutamate receptors critically involved in neuronal function and epilepsy. While we found no evidence for synaptic KARs in MCs, KAR activation induced strong action potential firing of MCs, raising the possibility that extracellular KARs regulate MC excitability in vivo and may also promote dentate gyrus hyperexcitability and epileptogenesis.
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- 2022
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27. Mucosal-associated invariant T cells have therapeutic potential against ocular autoimmunity
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Koh Hei Sonoda, Eiichi Hasegawa, Kensuke Shibata, Sho Yamasaki, Nobuyo Yawata, Satoshi Yamana, Atsunobu Takeda, Mitsuru Arima, and Shotaro Shimokawa
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business.industry ,T cell ,Immunology ,Interleukin ,Retinal ,Mucosal associated invariant T cell ,medicine.disease_cause ,Neuroprotection ,eye diseases ,Autoimmunity ,Interleukin 22 ,chemistry.chemical_compound ,medicine.anatomical_structure ,Antigen ,chemistry ,medicine ,Immunology and Allergy ,business - Abstract
Autoimmune uveitis is a sight-threatening disease induced by pathogenic T cells that recognize retinal antigens; it is observed in disorders including Vogt-Koyanagi-Harada disease (VKH). The roles of specific T cell subsets and their therapeutic potential against autoimmune uveitis are not fully understood. Here we conducted multi-parametric single-cell protein quantification which shows that the frequency of CD161highTRAV1-2+ mucosal-associated invariant T (MAIT) cells that recognize vitamin B2 metabolite-based antigens is decreased in relapsing VKH patients compared to individuals without active ocular inflammation. An experimental autoimmune uveitis (EAU) mouse model revealed that genetic depletion of MAIT cells reduced the expression of interleukin (Il) 22 and exacerbated retinal pathology. Reduced IL-22 levels were commonly observed in patients with relapsing VKH compared to individuals without active ocular inflammation. Both mouse and human MAIT cells produced IL-22 upon stimulation with their antigenic metabolite in vitro. An intravitreal administration of the antigenic metabolite into EAU mice induced retinal MAIT cell expansion and enhanced the expressions of Il22, as well as its downstream genes related to anti-inflammatory and neuroprotective effects, leading to an improvement in both retinal pathology and visual function. Taken together, we demonstrate that a metabolite-driven approach targeting MAIT cells has therapeutic potential against autoimmune uveitis.
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- 2022
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28. Predictive Biomarkers for the Ranking of Pulmonary Toxicity of Nanomaterials
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Chinatsu Nishida, Hiroto Izumi, Taisuke Tomonaga, Jun-ichi Takeshita, Ke-Yong Wang, Kei Yamasaki, Kazuhiro Yatera, and Yasuo Morimoto
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biomarker ,pulmonary toxicity ,chemokine ,nanomaterials ,Chemistry ,QD1-999 - Abstract
We analyzed the mRNA expression of chemokines in rat lungs following intratracheal instillation of nanomaterials in order to find useful predictive markers of the pulmonary toxicity of nanomaterials. Nickel oxide (NiO) and cerium dioxide (CeO2) as nanomaterials with high pulmonary toxicity, and titanium dioxide (TiO2) and zinc oxide (ZnO) as nanomaterials with low pulmonary toxicity, were administered into rat lungs (0.8 or 4 mg/kg BW). C-X-C motif chemokine 5 (CXCL5), C-C motif chemokine 2 (CCL2), C-C motif chemokine 7 (CCL7), C-X-C motif chemokine 10 (CXCL10), and C-X-C motif chemokine 11 (CXCL11) were selected using cDNA microarray analysis at one month after instillation of NiO in the high dose group. The mRNA expression of these five genes were evaluated while using real-time quantitative polymerase chain reaction (RT-qPCR) from three days to six months after intratracheal instillation. The receiver operating characteristic (ROC) results showed a considerable relationship between the pulmonary toxicity ranking of nanomaterials and the expression of CXCL5, CCL2, and CCL7 at one week and one month. The expression levels of these three genes also moderately or strongly correlated with inflammation in the lung tissues. Three chemokine genes can be useful as predictive biomarkers for the ranking of the pulmonary toxicity of nanomaterials.
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- 2020
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29. Effect of Handgrip Strength on Clinical Outcomes of Patients with Hepatocellular Carcinoma Treated with Lenvatinib
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Yurika Kotoh, Issei Saeki, Takahiro Yamasaki, Ryo Sasaki, Norikazu Tanabe, Takashi Oono, Takashi Matsuda, Takuro Hisanaga, Toshihiko Matsumoto, Isao Hidaka, Tsuyoshi Ishikawa, Taro Takami, and Isao Sakaida
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hepatocellular carcinoma ,handgrip strength ,lenvatinib ,skeletal muscle ,survival ,time to treatment failure ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Previous studies have reported prognostic factors for hepatocellular carcinoma (HCC) patients receiving lenvatinib; however, no studies have evaluated the effects of both handgrip strength and skeletal muscle mass on the clinical outcomes. Therefore, this retrospective study investigated the individual effect of handgrip strength, skeletal muscle mass, and sarcopenia on clinical outcomes of 53 HCC patients treated with lenvatinib. Before receiving lenvatinib, handgrip strength and skeletal muscle index (SMI) were measured. Low handgrip strength and muscle depletion were defined as 2/m2 in men and women, respectively. Sarcopenia was defined as having low handgrip strength and muscle depletion. Multivariate analysis identified modified albumin–bilirubin grade 1–2a (p = 0.010), Barcelona Clinic Liver Cancer stage A–B (p = 0.011), and absence of low handgrip strength (p = 0.015) as favorable prognostic factors for survival. Furthermore, sarcopenia was an independent significant prognostic factor for survival. Time to treatment failure was associated with handgrip strength and sarcopenia. Our findings suggest that handgrip strength may be a useful marker of clinical outcomes in HCC patients treated with lenvatinib.
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- 2020
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30. Low-Temperature Activation of Methane with Nitric Oxide and Formation of Hydrogen Cyanide over an Alumina-Supported Platinum Catalyst
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Tetsuya Kodaira, Li Xiaohong, Nobuya Suganuma, Kyoko K. Bando, Song Yang, Tetsuya Shishido, Atsushi Nishida, Atsushi Takagaki, Junichi Murakami, Tatsumi Ishihara, and Tatsuya Yamasaki
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chemistry.chemical_compound ,Chemistry ,Platinum catalyst ,Inorganic chemistry ,Hydrogen cyanide ,General Chemistry ,Catalysis ,Methane ,Nitric oxide - Published
- 2021
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31. An in-vitro comparative study of the binding of caspofungin and micafungin to plasma proteins
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Kenji Tsukigawa, Keishi Yamasaki, Hakaru Seo, Masaki Otagiri, Koji Nishi, Kazuaki Taguchi, and Keiki Sakurama
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Antifungal Agents ,Pharmaceutical Science ,Serum Albumin, Human ,Microbial Sensitivity Tests ,Plasma protein binding ,In Vitro Techniques ,Echinocandins ,chemistry.chemical_compound ,Caspofungin ,polycyclic compounds ,medicine ,Humans ,Binding site ,Pharmacology ,Binding Sites ,Chemistry ,Micafungin ,Blood Proteins ,Orosomucoid ,bacterial infections and mycoses ,Human serum albumin ,Molecular biology ,Blood proteins ,Free fraction ,Invasive Fungal Infections ,Protein Binding ,medicine.drug - Abstract
Objectives Echinocandins are widely used for the treatment of invasive fungal diseases. While they bind strongly to plasma proteins, our knowledge of this process is not sufficient to permit their pharmacokinetics and pharmacodynamics targets to be discussed. In this study, we characterized the binding of two echinocandins, caspofungin and micafungin, to plasma proteins, human serum albumin (HSA) and human α 1-acid glycoprotein (AAG). Methods The binding parameters, number of binding sites (n) and association constant (K) for caspofungin and micafungin to HSA and AAG were determined by equilibrium dialysis. The binding site on HSA for these echinocandins was identified by conducting inhibition experiments. Key findings Caspofungin was found to bind strongly to a single site on HSA (n = 1.26, K = 0.45 × 106 M−1) and AAG (n = 0.99, K = 0.29 × 106 M−1). Micafungin was found to bind more strongly to HSA (n = 1.35, K = 1.44 × 106 M−1) and AAG (n = 1.32, K = 1.16 × 106 M−1). The binding site for these drugs on HSA appears to be within subdomain IA. Conclusions Free fraction of caspofungin and micafungin in patients may not be substantially affected due to the contribution of AAG to the overall protein binding and the binding to subdomain IA on HSA, which is different from the major drug-binding sites within subdomains IB, IIA and IIIA.
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- 2021
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32. Characterization of a novel nicotinamide adenine dinucleotide-cytochrome b5 reductase mutation associated with canine hereditary methemoglobinemia
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Reeko Sato, Yayoi Otsuka-Yamasaki, Haruka Shino, Osamu Inanami, and Masahiro Yamasaki
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Nonsynonymous substitution ,040301 veterinary sciences ,CYB5R3 ,Reductase ,Nicotinamide adenine dinucleotide ,Methemoglobinemia ,Cat Diseases ,Biochemistry ,0403 veterinary science ,03 medical and health sciences ,chemistry.chemical_compound ,Dogs ,medicine ,Missense mutation ,Animals ,Dog Diseases ,Cytochrome b5 reductase ,030304 developmental biology ,0303 health sciences ,General Veterinary ,Nicotinamide ,Full Paper ,Chemistry ,missense mutation ,nicotinamide adenine dinucleotide-cytochrome b5 reductase ,04 agricultural and veterinary sciences ,hereditary methemoglobinemia ,medicine.disease ,NAD ,Molecular biology ,Cytochromes b5 ,Mutation ,dog ,Cats ,Cytochrome-B(5) Reductase - Abstract
Hereditary methemoglobinemia associated with nicotinamide adenine dinucleotide-cytochrome b5 reductase (b5R) deficiency is a rare autosomal recessive disorder in animals. Recently, nonsynonymous b5R gene (CYB5R3) variants have been reported to be associated with canine and feline hereditary methemoglobinemia. However, the underlying molecular mechanisms of canine and feline methemoglobinemia caused by these nonsynonymous variants have not yet been reported. Previously, we reported a Pomeranian dog family with hereditary methemoglobinemia, carrying CYB5R3 mutation of an A>C transition at codon 194 in exon 7, replacing an isoleucine residue with leucine (p.Ile194Leu). In this study, we investigated the enzymatic and structural properties of the soluble form of wild-type and Ile194Leu canine b5Rs to characterize the effects of this missense mutation. Our results showed that the kinetic properties of the mutant enzyme were not affected by this amino acid substitution. The secondary structure of the wild-type and Ile194Leu b5Rs detected by circular dichroism showed a similar pattern. However, the mutant enzyme exhibited decreased heat stability and increased susceptibility to trypsin hydrolysis. Moreover, the thermostability and unfolding measurements indicated that the mutant enzyme was more sensitive to temperature-dependent denaturation than the wild-type b5R. We concluded from these results that unstable mutant enzyme properties with normal enzymatic activity would be associated with hereditary methemoglobinemia in the Pomeranian dog family.
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- 2021
33. Dependence of Oxygen Concentration and Temperature on the Growth Rate Distribution of SiO2 Solid Film by Chemical Vapor Deposition in the Hexamethyldisiloxane-oxygen System
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Yuto Yamasaki, Ken-ichiro Tanoue, and Misaki Honda
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Hexamethyldisiloxane ,chemistry.chemical_compound ,General Energy ,Materials science ,chemistry ,Chemical engineering ,Limiting oxygen concentration ,Growth rate ,Chemical vapor deposition ,Oxygen system ,Solid film - Published
- 2021
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34. APR-246 induces apoptosis and enhances chemo-sensitivity via activation of ROS and TAp73-Noxa signal in oesophageal squamous cell cancer with TP53 missense mutation
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Koji Tanaka, Tsuyoshi Takahashi, Yukinori Kurokawa, Tomoki Makino, Kotaro Yamashita, Makoto Yamasaki, Kiyokazu Nakajima, Hidetoshi Eguchi, Yuichiro Doki, Eiichi Morii, Takuro Saito, and Teruyuki Kobayashi
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Quinuclidines ,Cancer Research ,Esophageal Neoplasms ,Mutation, Missense ,Apoptosis ,Article ,Mice ,Downregulation and upregulation ,Western blot ,In vivo ,Cell Line, Tumor ,medicine ,Animals ,Humans ,Missense mutation ,Viability assay ,neoplasms ,chemistry.chemical_classification ,Reactive oxygen species ,medicine.diagnostic_test ,Tumor Protein p73 ,Xenograft Model Antitumor Assays ,digestive system diseases ,Up-Regulation ,Proto-Oncogene Proteins c-bcl-2 ,Oncology ,chemistry ,Cell culture ,Cancer research ,Esophageal Squamous Cell Carcinoma ,Tumor Suppressor Protein p53 ,Reactive Oxygen Species ,Signal Transduction - Abstract
Background Mutations in p53, identified in 90% of oesophageal squamous cell carcinoma (ESCC), are associated with unfavourable prognosis and chemo-resistance. APR-246 induces apoptosis by restoring transcriptional ability of mutant p53, and may be a promising therapeutic agent to overcome chemo-resistance in ESCC. Methods In ESCC cell lines differing in p53 status, we performed in vitro cell viability and apoptosis assays, evaluated reactive oxygen species (ROS) generation, and assessed signal changes by western blot after APR-246 administration with/without chemo-agent. Antitumour effects and signal changes were evaluated in in vivo experiments using xenograft and patient-derived xenograft (PDX) mouse models. Results APR-246 administration induced significant apoptosis by upregulating p73 and Noxa via ROS induction in ESCC cell lines harbouring p53 missense mutations. Moreover, APR-246 plus chemotherapy exerted combined antitumour effects in ESCC with p53 missense mutations. This effect was also mediated through enhanced ROS activity, leading to massive apoptosis via upregulation of p73 and Noxa. These findings were confirmed by xenograft and PDX models with p53 mutant ESCC. Conclusion APR-246 strongly induced apoptosis by inducing ROS activity and p73-Noxa signalling, specifically in ESCC with p53 missense mutation. This antitumour effect was further enhanced by combination with 5-FU, which we first confirmed in ESCC preclinical model.
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- 2021
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35. Chemotherapy-induced autoimmune-mediated encephalitis during germinoma treatment
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Naoki Yamada, Hiroshi Sakuma, Naohiro Yamamoto, Ichiro Kuki, Junichi Hara, and Kai Yamasaki
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Chemotherapy ,Germinoma ,business.industry ,medicine.medical_treatment ,Autoantibody ,Induction chemotherapy ,Neopterin ,General Medicine ,medicine.disease ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Developmental Neuroscience ,chemistry ,Pediatrics, Perinatology and Child Health ,Acute disseminated encephalomyelitis ,Immunology ,medicine ,Infectious encephalitis ,Neurology (clinical) ,business ,030217 neurology & neurosurgery ,Encephalitis - Abstract
Background Autoimmune mediated encephalitis (AME), which includes autoantibody-associated encephalitis and acute disseminated encephalomyelitis, is a common cause of encephalitis as well as infectious encephalitis in children. AME may be triggered by autoimmune responses to paraneoplastic syndromes and infections. Infectious encephalitis associated with an immunocompromised status caused by anti-cancer chemotherapy is well recognized; however, there have been few reports on the relationship between AME and chemotherapy. Case report A ten-year-old previously healthy, developmentally normal girl was diagnosed with a pure germinoma in the suprasellar region. Following 30 days of induction chemotherapy, she developed a depressed level of consciousness with accompanying right hemiplegia, aphasia, and unexplained fever. Cerebrospinal fluid (CSF) analysis revealed positive oligoclonal bands and elevated neopterin levels. Neither atypical cells suggesting tumor exacerbation nor pathogens known to cause encephalitis were identified in the CSF. She was administrated immunosuppressive therapy and her symptoms rapidly improved. No known autoantibodies associated with autoantibody-associated encephalitis were identified in blood or CSF. However, the presence of oligoclonal bands and elevated neopterin levels in the CSF, and the favorable response to immunosuppressive therapy were consistent with an AME diagnosis. Thirteen days after the third course of chemotherapy, the patient developed a depressed level of consciousness again. Due to the recurrence of encephalitis, re-administration of immunosuppressive therapy was performed, which led to improvement in her symptoms. Recurrence of encephalitis has not occurred for 1 year after completion of chemotherapy. Conclusion The chemotherapy-induced abnormal immune response might have triggered the AME.
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- 2021
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36. Isolated neutropenia caused by copper deficiency due to jejunal feeding and excessive zinc intake: A case report
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Masao Kumode, Ryo Sumimoto, Takafumi Miyachi, Masami Yamasaki, Hiroko Kodama, Masahiko Takemoto, Hiromitsu Ohmori, and Tomio Matsumoto
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medicine.medical_specialty ,Neutropenia ,business.industry ,chemistry.chemical_element ,General Medicine ,Zinc ,medicine.disease ,Copper ,Zinc intake ,Endocrinology ,chemistry ,hemic and lymphatic diseases ,Internal medicine ,Case report ,Medicine ,Deficiency ,Percutaneous endoscopic gastrostomy with jejunal extension feeding ,business ,Copper deficiency - Abstract
BACKGROUND Percutaneous endoscopic gastrostomy with jejunal extension (PEG-J) is often used to treat patients with neurological impairment and difficulty in swallowing. However, these patients often develop copper deficiency. This report describes a case of isolated neutropenia, which is a rare manifestation of copper deficiency. CASE SUMMARY Our patient was a 19-year-old boy with neurological impairment and gastroesophageal reflux. He received PEG-J feeding, including an enteral supplement containing copper and zinc. However, as his serum zinc level was low (53 μg/dL) at the age of 19 years and 2 mo, we changed to a zinc-rich supplement containing 22 mg/d of zinc and 1.0 mg/d of copper. The supplement comprised a mixture of isocal 1.0 junior (5 packs/d), Tezon [2 packs (250 mL)/d], and cocoa powder. Seven months later, he had neutropenia (606/mm3) with a serum copper level of 16 μg/dL. There were no other manifestations of copper deficiency, including anemia. Copper deficiency and neutropenia both improved following the administration of cocoa powder and Tezon. CONCLUSION In patients receiving long-term PEG-J feeds, white blood cell counts, hemoglobin, and serum levels of copper and zinc should be regularly monitored.
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- 2021
37. COVID-19 and adult-onset Still’s disease as part of hyperferritinemic syndromes
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Hiroyuki Kunishima, Yamasaki Yukitaka, Tomofumi Kiyokawa, Machiko Mizushima, Kazuko Yamazaki, Tatsuya Kawasaki, Seido Ooka, Kumiko Tonooka, Kimito Kawahata, Yuta Nakamura, Yutaka Goto, Shotaro Suzuki, Tsutomu Sakurada, Keiichi Sakurai, and Hiroki Ikeda
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Adult ,Pediatrics ,medicine.medical_specialty ,Prednisolone ,Case Report ,Ciclesonide ,Antibodies, Monoclonal, Humanized ,Catastrophic antiphospholipid syndrome ,AcademicSubjects/MED00160 ,tocilizumab ,chemistry.chemical_compound ,Tocilizumab ,hyperferritinemia ,medicine ,Humans ,AcademicSubjects/MED00360 ,adult onset Still’s disease ,Hemophagocytic lymphohistiocytosis ,cyclesonide ,business.industry ,Septic shock ,Macrophage Activation Syndrome ,COVID-19 ,medicine.disease ,Rash ,COVID-19 Drug Treatment ,chemistry ,Macrophage activation syndrome ,Ferritins ,medicine.symptom ,AcademicSubjects/MED00010 ,business ,Still's Disease, Adult-Onset ,medicine.drug - Abstract
The coronavirus disease (COVID-19) is known to cause hyperferritinemia and hemophagocytic lymphohistiocytosis (HLH). Including this laboratory parameter, clinical symptoms similar to COVID-19 have been observed in adult-onset Still’s disease (AOSD), catastrophic antiphospholipid syndrome (CAPS), macrophage activation syndrome (MAS), and septic shock, which has led to the proposal of a concept called ‘hyperferritinemic syndromes.’ Additionally, high levels of some clinical markers in both COVID-19 and AOSD make them difficult to differentiate. While the efficacy of ciclesonide had been expected for mild pneumonia with COVID-19, the efficacy of tocilizumab, which is a known treatment for AOSD, was not established. Here, we report the first known occurrence of COVID-19, diagnosed in March 2020, preceded by the diagnosis of AOSD, in April 2019, in a 65-year-old, otherwise healthy man. Following the diagnosis of the latter, the patient was first given prednisolone and then tocilizumab, which led to remission. With the recurrence of joint pain and rash in March 2020, accompanied by low oxygen saturation levels (90%), and ground-glass appearance on chest CT, PCR test revealed COVID-19 infection. Ciclesonide was started on day 7 of the disease onset, which led to improved inflammatory markers by day 21. Thus, we infer that while tocilizumab is theoretically useful for COVID-19 due to its inhibition of interleukin 6 (IL-6), additional ciclesonide therapy might be required to prevent worsening of the condition. AOSD and COVID-19 must, therefore, be differentiated by levels of ferritin which differ between the two, and appropriate treatment must be allocated.
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- 2021
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38. JNETS clinical practice guidelines for gastroenteropancreatic neuroendocrine neoplasms: diagnosis, treatment, and follow-up: a synopsis
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Yuji Nakamoto, Shinji Uemoto, Mitsuhiro Kida, Shinya Uchino, Wataru Kimura, Atsushi Kudo, Tsuyoshi Konishi, Masau Sekiguchi, Koichi Hirata, Izumi Komoto, Hisato Igarashi, Robert Yoshiyuki Osamura, Akihiro Sakurai, Hironobu Sasano, Tetsuhide Ito, Nobuyuki Ohike, Takuji Okusaka, Toshihiko Masui, Ippei Matsumoto, Masanori Yamasaki, Noritoshi Kobayashi, Yoshiyuki Majima, Motohiro Kojima, Yasutoshi Kimura, Chigusa Morizane, Nao Fujimori, Robert T. Jensen, Ryuichiro Doi, Masayuki Imamura, Atsuko Kasajima, Satoshi Hirano, Nobumasa Mizuno, Takeshi Aoki, Takao Ohtsuka, Akira Shimatsu, Masafumi Ikeda, Koji Takano, Tomoyuki Okumura, Jun Matsubayashi, Yuichi Sato, Yuichi Ishikawa, Kiyomi Horiuchi, Koji Morita, Susumu Hijioka, Shinichi Abe, Masao Tanaka, Yoshitaka Honma, Taku Aoki, Kazuhiko Nakamura, and Ryoji Kushima
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Oncology ,medicine.medical_specialty ,Aftercare ,Guidelines as Topic ,Disease ,Lanreotide ,Malignancy ,Japanese Neuroendocrine Tumor Society ,Metastasis ,chemistry.chemical_compound ,Stomach Neoplasms ,Surgical oncology ,Internal medicine ,Intestinal Neoplasms ,Humans ,Medicine ,MEN1 ,Multiple endocrine neoplasia ,Clinical practice guideline ,Gastroenteropancreatic neuroendocrine neoplasm ,Original Article—Liver, Pancreas, and Biliary Tract ,Everolimus ,business.industry ,Gastroenterology ,medicine.disease ,Pancreatic Neoplasms ,Neuroendocrine Tumors ,chemistry ,business ,medicine.drug - Abstract
Neuroendocrine neoplasms (NENs) are rare neoplasms that occur in various organs and present with diverse clinical manifestations. Pathological classification is important in the diagnosis of NENs. Treatment strategies must be selected according to the status of differentiation and malignancy by accurately determining whether the neoplasm is functioning or nonfunctioning, degree of disease progression, and presence of metastasis. The newly revised Clinical Practice Guidelines for Gastroenteropancreatic Neuroendocrine Neoplasms (GEP-NENs) comprises 5 chapters—diagnosis, pathology, surgical treatment, medical and multidisciplinary treatment, and multiple endocrine neoplasia type 1 (MEN1)/von Hippel–Lindau (VHL) disease—and includes 51 clinical questions and 19 columns. These guidelines aim to provide direction and practical clinical content for the management of GEP-NEN preferentially based on clinically useful reports. These revised guidelines also refer to the new concept of “neuroendocrine tumor” (NET) grade 3, which is based on the 2017 and 2019 WHO criteria; this includes health insurance coverage of somatostatin receptor scintigraphy for NEN, everolimus for lung and gastrointestinal NET, and lanreotide for GEP-NET. The guidelines also newly refer to the diagnosis, treatment, and surveillance of NEN associated with VHL disease and MEN1. The accuracy of these guidelines has been improved by examining and adopting new evidence obtained after the first edition was published. Supplementary Information The online version contains supplementary material available at 10.1007/s00535-021-01827-7.
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- 2021
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39. Novel Reversible-Binding PET Ligands for Imaging Monoacylglycerol Lipase Based on the Piperazinyl Azetidine Scaffold
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Ahmed Haider, Jian Rong, Steven H. Liang, Huiyi Wei, Daisuke Ogasawara, Masayuki Fujinaga, Tuo Shao, Wakana Mori, Shuyin Gu, Hao Xu, Michael A. Schafroth, Lin Xie, Yuancheng Gou, Ming-Rong Zhang, Thomas Lee Collier, Jiahui Chen, Katsushi Kumata, Zhen Chen, Richard Van, Yihan Shao, Lu Wang, Zhiwei Xiao, Xiaotian Xia, Kuan Hu, Bao Liang, Tomoteru Yamasaki, Richard E. Carson, Yiding Zhang, Fuwen Pang, Benjamin F. Cravatt, Yang Fang, Chunyu Zhao, and Atsuto Hiraishi
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Models, Molecular ,Azetidine ,Ligands ,01 natural sciences ,Article ,Proinflammatory cytokine ,Structure-Activity Relationship ,03 medical and health sciences ,chemistry.chemical_compound ,Drug Discovery ,Radioligand ,Animals ,Distribution (pharmacology) ,030304 developmental biology ,Serine protease ,0303 health sciences ,Binding Sites ,Dose-Response Relationship, Drug ,Molecular Structure ,biology ,010405 organic chemistry ,Haplorhini ,Monoacylglycerol Lipases ,Rats ,0104 chemical sciences ,3. Good health ,Monoacylglycerol lipase ,Eicosanoid ,chemistry ,Biochemistry ,Positron-Emission Tomography ,biology.protein ,Azetidines ,Molecular Medicine ,Arachidonic acid ,Radiopharmaceuticals - Abstract
Monoacylglycerol lipase (MAGL) is a 33 kDa serine protease primarily responsible for hydrolyzing 2-arachidonoylglycerol into the proinflammatory eicosanoid precursor arachidonic acid in the central nervous system. Inhibition of MAGL constitutes an attractive therapeutic concept for treating psychiatric disorders and neurodegenerative diseases. Herein, we present the design and synthesis of multiple reversible MAGL inhibitor candidates based on a piperazinyl azetidine scaffold. Compounds 10 and 15 were identified as the best-performing reversible MAGL inhibitors by pharmacological evaluations, thus channeling their radiolabeling with fluorine-18 in high radiochemical yields and favorable molar activity. Furthermore, evaluation of [18F]10 and [18F]15 ([18F]MAGL-2102) by autoradiography and positron emission tomography (PET) imaging in rodents and nonhuman primates demonstrated favorable brain uptakes, heterogeneous radioactivity distribution, good specific binding, and adequate brain kinetics, and [18F]15 demonstrated a better performance. In conclusion, [18F]15 was found to be a suitable PET radioligand for the visualization of MAGL, harboring potential for the successful translation into humans.
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- 2021
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40. Assessment of direct binding interaction between CD36 and its potential lipid ligands using a peptide mimic of the receptor labeled with a fluorophore
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Yuki Manabe, Tsutomu Sasaki, Yusaku Kimoto, Tatsuya Sugawara, Masayuki Yamasaki, Kazuo Inoue, and Satoshi Tsuzuki
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CD36 Antigens ,chemistry.chemical_classification ,biology ,Ligand ,CD36 ,Cell Differentiation ,Peptide ,General Medicine ,Ligands ,General Biochemistry, Genetics and Molecular Biology ,Amino acid ,chemistry.chemical_compound ,A-site ,chemistry ,Biochemistry ,Phosphatidylcholine ,biology.protein ,Peptides ,Receptor ,Fluorescein isothiocyanate ,Protein Binding - Abstract
Cluster of differentiation 36 (CD36) is a cell-surface receptor that recognizes diverse substances. We have presented indirect evidence that a short segment of the receptor comprising amino acids 149-168 contains a site for binding of its lipid ligands (e.g., distinct fatty acids and aldehydes). However, experimental support for their direct interactions is yet to be achieved. For this, we devised a fluorescence intensity assay, where a synthetic peptide consisting of CD36 amino acids 149-168 labeled with fluorescein isothiocyanate (FITC-CD36149-168) and its variant peptides were used as positive and negative probes, respectively. First, we obtained results indicating that 1-palmitoyl-2-(5-keto-6-octenedioyl)phosphatidylcholine (an established CD36 ligand) but not 1-palmitoyl-2-arachidonyl-phosphatidylcholine (a non-ligand of the receptor) bound in a saturable and specific manner to FITC-CD36149-168. Strikingly, the assay allowed us to provide the first evidence supporting direct and specific binding between the CD36 segment and fatty aldehydes (e.g., Z-11-hexadecenal). However, this method failed to illustrate specific interactions of the segment with fatty acids, such as oleic acid. Nonetheless, our findings offer further insight into the biologically relevant ligands and the role of CD36. In addition, we suggest that this fluorescence-based technique provides a convenient means to evaluate protein (peptide)-lipid interactions.
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- 2021
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41. Kamikihito improves cancer‐related fatigue in castration‐resistant prostate cancer patients receiving enzalutamide: Multidimensional approach including metabolomics analysis
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Sayaka Yasuda, Katsuya Ohbuchi, Takeshi Yamasaki, Satoshi Tamada, Junzo Nojima, Kyoko Ebisu, Yasuyoshi Watanabe, Minoru Kato, Taro Iguchi, Naoko Tsuchiya, and Chika Shimobori
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Oncology ,medicine.medical_specialty ,business.industry ,Castration resistant ,medicine.disease ,chemistry.chemical_compound ,Prostate cancer ,Metabolomics ,chemistry ,Internal medicine ,Medicine ,Enzalutamide ,medicine.symptom ,business ,Cancer-related fatigue ,Kamikihito - Published
- 2021
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42. Generation of Tetrafluoroethylene–Propylene Elastomer-Based Microfluidic Devices for Drug Toxicity and Metabolism Studies
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Norihito Nakazawa, Emi Sano, Masahiro Tsuda, Keisuke Yagi, Sayaka Deguchi, Aya Wada, Shinsuke Yamasaki, Mengyang Wang, Naoki Matsuoka, Chihiro Mori, Hiroyuki Mizuguchi, Tsuyoshi Kawai, Kazuo Takayama, Masahide Yodogawa, Fumiyoshi Yamashita, Kaori Kosugi, and Yu Suke Torisawa
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Drug ,Aromatic compounds ,General Chemical Engineering ,media_common.quotation_subject ,Microfluidic devices ,Article ,Absorption ,chemistry.chemical_compound ,medicine ,Cytotoxicity ,QD1-999 ,media_common ,Polydimethylsiloxane ,Chemistry ,Drug discovery ,Bufuralol ,technology, industry, and agriculture ,General Chemistry ,Pulmonary respiration ,Metabolism ,medicine.anatomical_structure ,Hepatocyte ,Biophysics ,Layers ,Drug metabolism - Abstract
Polydimethylsiloxane (PDMS) is widely used to fabricate microfluidic organs-on-chips. Using these devices (PDMS-based devices), the mechanical microenvironment of living tissues, such as pulmonary respiration and intestinal peristalsis, can be reproduced in vitro. However, the use of PDMS-based devices in drug discovery research is limited because of their extensive absorption of drugs. In this study, we investigated the feasibility of the tetrafluoroethylene–propylene (FEPM) elastomer to fabricate a hepatocyte-on-a-chip (FEPM-based hepatocyte chip) with lower drug absorption. The FEPM-based hepatocyte chip expressed drug-metabolizing enzymes, drug-conjugating enzymes, and drug transporters. Also, it could produce human albumin. Although the metabolites of midazolam and bufuralol were hardly detected in the PDMS-based hepatocyte chip, they were detected abundantly in the FEPM-based hepatocyte chip. Finally, coumarin-induced hepatocyte cytotoxicity was less severe in the PDMS-based hepatocyte chip than in the FEPM-based hepatocyte chip, reflecting the different drug absorptions of the two chips. In conclusion, the FEPM-based hepatocyte chip could be a useful tool in drug discovery research, including drug metabolism and toxicity studies., フッ素系エラストマー素材を用いた肝臓チップの開発と薬物代謝・毒性試験への応用. 京都大学プレスリリース. 2021-09-16., Drug testing on miniatured livers. 京都大学プレスリリース. 2021-09-17.
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- 2021
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43. Development of a Poly(2-ethyl-2-oxazoline)-Based Fluorescence Imaging Probe Targeting the Folate Receptor in Tumor Tissues
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Takahiro Mukai, Masayuki Munekane, Yoshie Haratake, Kohei Kijima, Toshihide Yamasaki, Natsuka Suzuno, Ling Bao, and Kohei Sano
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Fluorescence-lifetime imaging microscopy ,Polymers and Plastics ,Biochemistry ,Folate receptor ,Chemistry ,Process Chemistry and Technology ,Organic Chemistry ,2-ethyl-2-oxazoline ,Tumor tissue - Published
- 2021
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44. Ku-Band 70-/30-W-Class Internally Matched GaN Power Amplifiers With Low IMD3 Over a Wide Offset Frequency Range of Up To 400 MHz
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Kenji Harauchi, Miyo Miyashita, Takumi Sugitani, Takaaki Yoshioka, Kazuya Yamamoto, Seiki Goto, Maehara Hiroaki, Hiroaki Ichinohe, and Takashi Yamasaki
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Materials science ,business.industry ,Amplifier ,dBc ,Gallium nitride ,Ku band ,law.invention ,chemistry.chemical_compound ,IMD3 ,chemistry ,law ,Optoelectronics ,Electrical and Electronic Engineering ,Resistor ,business ,Short circuit ,Intermodulation - Abstract
This study describes the Ku -band 70- and 30-W-class internally matched gallium nitride (GaN) power amplifiers (PAs) for multi-carrier satellite communications (SatComs). The GaN PAs maintain low third-order intermodulation distortion (IMD3) over a wide offset frequency range of up to 400 MHz, whereas in the Ku -band, one PA can deliver a high peak output power of approximately 70 W and the other PA, a peak output power of higher than 30 W. To realize a wide offset frequency operation, our proposed output-matching circuit includes three different types of difference-frequency short circuits, two of which are embedded into a tournament-shaped output-matching circuit inside the PA package and the rest is embedded into the drain bias feed placed outside the package. To verify the short-circuit design and its effectiveness, two different power classes (70 and 30 W), Ku -band GaN PAs, were designed and fabricated, and then, their output transfer characteristics focusing on IMD3 were measured. The measurements show that the 70-W-class GaN PA achieves a peak output power of 48.6 dBm while maintaining a linear output power of over 40 dBm and an IMD3 of less than −26 dBc over wide offset frequencies ranging from 1 to 400 MHz. The 30-W-class GaN PA maintains a linear output power of over 36.3 dBm and an IMD3 of less than −27 dBc over wide offset frequencies of up to approximately 600 MHz. To the best of the authors’ knowledge, these PAs have a record output power level over a wide frequency range of 1–400 MHz or higher under the condition of a low IMD3 of less than −25 dBc, compared to previously reported Ku -band GaN PAs used for multi-carrier SatComs.
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- 2021
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45. Diamond: Carbon at its best
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Satoshi Yamasaki, Christoph E. Nebel, and Nianjun Yang
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Materials science ,chemistry ,Metallurgy ,engineering ,Diamond ,chemistry.chemical_element ,General Materials Science ,General Chemistry ,engineering.material ,Carbon - Published
- 2021
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46. Protein Engineering of <scp>d</scp> ‐Succinylase from Cupriavidus sp . for <scp>d</scp> ‐Amino Acid Synthesis and the Structural Implications
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Masayuki Yamasaki, Toshihide Yamada, Masayuki Azuma, Shinya Kumagai, Yoshiaki Nishiya, and Yosuke Sumida
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chemistry.chemical_classification ,D-amino acid synthesis ,chemistry ,Cupriavidus sp ,Biocatalysis ,Stereochemistry ,General Chemistry ,Crystal structure ,Protein engineering ,Enzyme catalysis ,Amino acid - Published
- 2021
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47. Design, Synthesis, and Evaluation of 11C-Labeled 3-Acetyl-Indole Derivatives as a Novel Positron Emission Tomography Imaging Agent for Diacylglycerol Kinase Gamma (DGKγ) in Brain
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Tomohiro Ohashi, Tomoteru Yamasaki, Yasuyuki Debori, Tatsuki Koike, Tomokazu Kusumoto, Ryouta Maeda, Masayuki Fujinaga, Akito Hata, Takeshi Wakabayashi, Yasushi Hattori, Ming-Rong Zhang, Miyanohana Yuhei, Ryo Yamashita, Maki Miyamoto, Yiding Zhang, and Hidekatsu Wakizaka
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Indole test ,chemistry.chemical_classification ,medicine.diagnostic_test ,Chemistry ,Diacylglycerol kinase gamma ,Phosphatidic acid ,Imaging agent ,chemistry.chemical_compound ,Enzyme ,Positron emission tomography ,Drug Discovery ,medicine ,Biophysics ,Molecular Medicine ,IC50 ,Diacylglycerol kinase - Abstract
Diacylglycerol kinase gamma (DGKγ) is a subtype of DGK enzyme, which catalyzes ATP-dependent conversion of diacylglycerol to phosphatidic acid. DGKγ, localized in the brain, plays an important role in the central nervous system. However, its function has not been widely investigated. Positron emission tomography (PET) imaging of DGKγ validates target engagement of therapeutic DGKγ inhibitors and investigates DGKγ levels under normal and disease conditions. In this study, we designed and synthesized a series of 3-acetyl indole derivatives as candidates for PET imaging agents for DGKγ. Among the synthesized compounds, 2-((3-acetyl-1-(6-methoxypyridin-3-yl)-2-methyl-1H-indol-5-yl)oxy)-N-methylacetamide (9) exhibited potent inhibitory activity (IC50 = 30 nM) against DGKγ and desirable physicochemical properties allowing efficient blood-brain barrier penetration and low levels of undesirable nonspecific binding. The radiolabeling of 9 followed by PET imaging of wild-type and DGKγ-deficient mice and rats indicated that [11C]9 ([11C]T-278) specifically binds to DGKγ and yields a high signal-to-noise ratio for DGKγ in rodent brains.
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- 2021
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48. Hydrotalcite-Supported Cobalt Phosphide Nanorods as a Highly Active and Reusable Heterogeneous Catalyst for Ammonia-Free Selective Hydrogenation of Nitriles to Primary Amines
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Seiji Yamazoe, Kiyotaka Nakajima, Ayako Nakata, Sho Yamaguchi, Min Sheng, Jun Yamasaki, Takato Mitsudome, and Tomoo Mizugaki
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Ammonia ,chemistry.chemical_compound ,Primary (chemistry) ,Hydrotalcite ,Renewable Energy, Sustainability and the Environment ,Chemistry ,General Chemical Engineering ,Cobalt phosphide ,Environmental Chemistry ,Nanorod ,General Chemistry ,Heterogeneous catalysis ,Nuclear chemistry - Published
- 2021
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49. Clearance of peripheral nerve misfolded mutant protein by infiltrated macrophages correlates with motor neuron disease progression
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Yuko Kobayakawa, Noriko Isobe, Ryo Yamasaki, Wataru Shiraishi, Yu Hashimoto, Takuya Matsushita, Jun Ichi Kira, and Senri Ko
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CCR2 ,Pathology ,medicine.medical_specialty ,Receptors, CCR2 ,animal diseases ,Science ,Neuroimmunology ,CX3C Chemokine Receptor 1 ,Mice, Transgenic ,Neuroprotection ,Article ,Mice ,Animal disease models ,CX3CR1 ,parasitic diseases ,medicine ,Animals ,Humans ,Peripheral Nerves ,Amyotrophic lateral sclerosis ,Motor Neuron Disease ,Multidisciplinary ,Chemistry ,Superoxide Dismutase ,Macrophages ,Wild type ,Glial biology ,hemic and immune systems ,Motor neuron ,Spinal cord ,medicine.disease ,medicine.anatomical_structure ,Spinal Cord ,Mutation ,Disease Progression ,Diseases of the nervous system ,Medicine ,Sciatic nerve ,Peripheral nervous system - Abstract
Macrophages expressing C–C chemokine receptor type 2 (CCR2) infiltrate the central and peripheral neural tissues of amyotrophic lateral sclerosis (ALS) patients. To identify the functional role of CCR2+ macrophages in the pathomechanisms of ALS, we used an ALS animal model, mutant Cu/Zn superoxide dismutase 1G93A (mSOD1)-transgenic (Tg) mice. To clarify the CCR2 function in the model, we generated SOD1G93A/CCR2Red fluorescence protein (RFP)/Wild type (WT)/CX3CR1Green fluorescence protein (GFP)/WT-Tg mice, which heterozygously express CCR2-RFP and CX3CR1-GFP, and SOD1G93A/CCR2RFP/RFP-Tg mice, which lack CCR2 protein expression and present with a CCR2-deficient phenotype. In mSOD1-Tg mice, mSOD1 accumulated in the sciatic nerve earlier than in the spinal cord. Furthermore, spinal cords of SOD1G93A/CCR2RFP/WT/CX3CR1GFP/WT mice showed peripheral macrophage infiltration that emerged at the end-stage, whereas in peripheral nerves, macrophage infiltration started from the pre-symptomatic stage. Before disease onset, CCR2+ macrophages harboring mSOD1 infiltrated sciatic nerves earlier than the lumbar cord. CCR2-deficient mSOD1-Tg mice showed an earlier onset and axonal derangement in the sciatic nerve than CCR2-positive mSOD1-Tg mice. CCR2-deficient mSOD1-Tg mice showed an increase in deposited mSOD1 in the sciatic nerve compared with CCR2-positive mice. These findings suggest that CCR2+ and CX3CR1+ macrophages exert neuroprotective functions in mSOD1 ALS via mSOD1 clearance from the peripheral nerves.
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- 2021
50. TrkB/BDNF Signaling Could Be a New Therapeutic Target for Pancreatic Cancer
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Masayo Umebayashi, Yasuhiro Oyama, Kosuke Yanai, Shinjiro Nagao, Kazunori Nakayama, Akiko Fujimura, Akio Yamasaki, Lin Na, Takashi Morisaki, Katsuya Nakamura, Shuntaro Nagai, and Hideya Onishi
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Cancer Research ,Small interfering RNA ,endocrine system diseases ,Carbazoles ,Tropomyosin receptor kinase B ,Indole Alkaloids ,chemistry.chemical_compound ,Neurotrophic factors ,Cell Line, Tumor ,Pancreatic cancer ,Humans ,Receptor, trkB ,Medicine ,RNA, Small Interfering ,Protein Kinase Inhibitors ,Cell Proliferation ,Membrane Glycoproteins ,business.industry ,Kinase ,Brain-Derived Neurotrophic Factor ,musculoskeletal, neural, and ocular physiology ,General Medicine ,medicine.disease ,Phenotype ,digestive system diseases ,Pancreatic Neoplasms ,nervous system ,Oncology ,chemistry ,Cell culture ,embryonic structures ,Cancer research ,RNA Interference ,K252a ,business ,Carcinoma, Pancreatic Ductal ,Signal Transduction - Abstract
Background/aim Tropomyosin-related kinase B (TrkB)/brain-derived neurotrophic factor (BDNF) signaling plays a role in inducing malignant phenotypes in several aggressive types of cancers. To create a conclusive therapy targeting TrkB/BDNF signaling in solid refractory cancers, the biological significance of TrkB/BDNF signaling was analyzed in pancreatic ductal adenocarcinoma (PDAC) cells. Materials and methods Three PDAC cell lines were used as target cells to investigate proliferation and invasiveness. Small interfering RNA (siRNA) and the TrkB tyrosine kinase inhibitor k252a were used as TrkB/BDNF signaling inhibitors. Results All PDAC cell lines expressed TrkB and BDNF. When TrkB and BDNF were inhibited by siRNA or k252a, the invasiveness of PANC-1 and SUIT-2 cells significantly decreased. When TrkB was inhibited by siRNA or k252a, proliferation was significantly inhibited in PDAC cells. Conclusion TrkB/BDNF signaling may be a new therapeutic target for PDAC. Therapies targeting TrkB/BDNF signaling may be a conclusive cancer therapy for refractory solid cancer.
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- 2021
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