192 results on '"Kotaro Oyama"'
Search Results
2. Hybrid Biophysics: Interdisciplinary approaches for trans-scale analysis of organism-environment interactions
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Madoka Suzuki, Kotaro Oyama, and Toshiko Yamazawa
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Biology (General) ,QH301-705.5 ,Physiology ,QP1-981 ,Physics ,QC1-999 - Published
- 2023
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3. Chronological T‐wave alternation before and after the onset of arrhythmogenic right ventricular cardiomyopathy
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Akira Sato, Hirofumi Saiki, Maki Kudo, Yurie Takizawa, Seiko Kuwata, Satoshi Nakano, Yumi Sato, Kunihiko Miura, Kotaro Oyama, and Manami Akasaka
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arrhthmogenic right ventricular cardiomyopathy ,heart failure ,one and one‐half repair ,school cardiac screening ,sudden cardiac death ,T wave ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Abstract Identification of arrhythmogenic right ventricular cardiomyopathy (ARVC) during childhood is challenging due to the lack of specific ECG manifestation. We report chronological ECG alteration before several years of the ARVC onset in two affected children. Their ECG at the age of 6 years was almost normal for their age, and their chronological ECGs exhibited inversion of T wave in inferior leads, which are typical for ARVC, developed at younger age than that in precordial leads. In addition, the leftmost T‐wave inversion in the precordial lead shifted toward the left in our patients, which is a sharp contrast to its physiological transition.
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- 2022
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4. A five-course meal symposium on 'The Future of Muscle is Now'
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Madoka Suzuki and Kotaro Oyama
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Biology (General) ,QH301-705.5 ,Physiology ,QP1-981 ,Physics ,QC1-999 - Published
- 2022
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5. Effects of omecamtiv mecarbil on the contractile properties of skinned porcine left atrial and ventricular muscles
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Tomohiro Nakanishi, Kotaro Oyama, Hiroyuki Tanaka, Fuyu Kobirumaki-Shimozawa, Shuya Ishii, Takako Terui, Shin’ichi Ishiwata, and Norio Fukuda
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Ca2+ sensitivity ,contractility ,myocardium ,sarcomere ,thin filament ,Physiology ,QP1-981 - Abstract
Omecamtiv mecarbil (OM) is a novel inotropic agent for heart failure with systolic dysfunction. OM prolongs the actomyosin attachment duration, which enhances thin filament cooperative activation and accordingly promotes the binding of neighboring myosin to actin. In the present study, we investigated the effects of OM on the steady-state contractile properties in skinned porcine left ventricular (PLV) and atrial (PLA) muscles. OM increased Ca2+ sensitivity in a concentration-dependent manner in PLV, by left shifting the mid-point (pCa50) of the force-pCa curve (ΔpCa50) by ∼0.16 and ∼0.33 pCa units at 0.5 and 1.0 μM, respectively. The Ca2+-sensitizing effect was likewise observed in PLA, but less pronounced with ΔpCa50 values of ∼0.08 and ∼0.22 pCa units at 0.5 and 1.0 μM, respectively. The Ca2+-sensitizing effect of OM (1.0 μM) was attenuated under enhanced thin filament cooperative activation in both PLV and PLA; this attenuation occurred directly via treatment with fast skeletal troponin (ΔpCa50: ∼0.16 and ∼0.10 pCa units in PLV and PLA, respectively) and indirectly by increasing the number of strongly bound cross-bridges in the presence of 3 mM MgADP (ΔpCa50: ∼0.21 and ∼0.08 pCa units in PLV and PLA, respectively). It is likely that this attenuation of the Ca2+-sensitizing effect of OM is due to a decrease in the number of “recruitable” cross-bridges that can potentially produce active force. When cross-bridge detachment was accelerated in the presence of 20 mM inorganic phosphate, the Ca2+-sensitizing effect of OM (1.0 μM) was markedly decreased in both types of preparations (ΔpCa50: ∼0.09 and ∼0.03 pCa units in PLV and PLA, respectively). The present findings suggest that the positive inotropy of OM is more markedly exerted in the ventricle than in the atrium, which results from the strongly bound cross-bridge-dependent allosteric activation of thin filaments.
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- 2022
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6. Study Profile of the Tohoku Medical Megabank Community-Based Cohort Study
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Atsushi Hozawa, Kozo Tanno, Naoki Nakaya, Tomohiro Nakamura, Naho Tsuchiya, Takumi Hirata, Akira Narita, Mana Kogure, Kotaro Nochioka, Ryohei Sasaki, Nobuyuki Takanashi, Kotaro Otsuka, Kiyomi Sakata, Shinichi Kuriyama, Masahiro Kikuya, Osamu Tanabe, Junichi Sugawara, Kichiya Suzuki, Yoichi Suzuki, Eiichi N Kodama, Nobuo Fuse, Hideyasu Kiyomoto, Hiroaki Tomita, Akira Uruno, Yohei Hamanaka, Hirohito Metoki, Mami Ishikuro, Taku Obara, Tomoko Kobayashi, Kazuyuki Kitatani, Takako Takai-Igarashi, Soichi Ogishima, Mamoru Satoh, Hideki Ohmomo, Akito Tsuboi, Shinichi Egawa, Tadashi Ishii, Kiyoshi Ito, Sadayoshi Ito, Yasuyuki Taki, Naoko Minegishi, Naoto Ishii, Masao Nagasaki, Kazuhiko Igarashi, Seizo Koshiba, Ritsuko Shimizu, Gen Tamiya, Keiko Nakayama, Hozumi Motohashi, Jun Yasuda, Atsushi Shimizu, Tsuyoshi Hachiya, Yuh Shiwa, Teiji Tominaga, Hiroshi Tanaka, Kotaro Oyama, Ryoichi Tanaka, Hiroshi Kawame, Akimune Fukushima, Yasushi Ishigaki, Tomoharu Tokutomi, Noriko Osumi, Tadao Kobayashi, Fuji Nagami, Hiroaki Hashizume, Tomohiko Arai, Yoshio Kawaguchi, Shinichi Higuchi, Masaki Sakaida, Ryujin Endo, Satoshi Nishizuka, Ichiro Tsuji, Jiro Hitomi, Motoyuki Nakamura, Kuniaki Ogasawara, Nobuo Yaegashi, Kengo Kinoshita, Shigeo Kure, Akio Sakai, Seiichiro Kobayashi, Kenji Sobue, Makoto Sasaki, and Masayuki Yamamoto
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prospective cohort studies ,great east japan earthquake ,genome cohort ,Medicine (General) ,R5-920 - Abstract
Background: We established a community-based cohort study to assess the long-term impact of the Great East Japan Earthquake on disaster victims and gene-environment interactions on the incidence of major diseases, such as cancer and cardiovascular diseases. Methods: We asked participants to join our cohort in the health check-up settings and assessment center based settings. Inclusion criteria were aged 20 years or over and living in Miyagi or Iwate Prefecture. We obtained information on lifestyle, effect of disaster, blood, and urine information (Type 1 survey), and some detailed measurements (Type 2 survey), such as carotid echography and calcaneal ultrasound bone mineral density. All participants agreed to measure genome information and to distribute their information widely. Results: As a result, 87,865 gave their informed consent to join our study. Participation rate at health check-up site was about 70%. The participants in the Type 1 survey were more likely to have psychological distress than those in the Type 2 survey, and women were more likely to have psychological distress than men. Additionally, coastal residents were more likely to have higher degrees of psychological distress than inland residents, regardless of sex. Conclusion: This cohort comprised a large sample size and it contains information on the natural disaster, genome information, and metabolome information. This cohort also had several detailed measurements. Using this cohort enabled us to clarify the long-term effect of the disaster and also to establish personalized prevention based on genome, metabolome, and other omics information.
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- 2021
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7. Regulatory T cells in Crohn's disease following anti‐TNF‐α therapy
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Toshimi Chiba, Mikiya Endo, Shoko Miura, Yuko Hayashi, Yoshiko Asakura, Kotaro Oyama, and Takayuki Matsumoto
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anti‐TNF‐α therapy ,CD127− ,Crohn's disease ,FoxP3+ ,Tregs ,Diseases of the digestive system. Gastroenterology ,RC799-869 - Abstract
Background and Aim Anti‐tumor necrosis factor alpha (TNF‐α) therapy is an effective therapy for Crohn's disease (CD). We investigated FoxP3+ and CD127− regulatory T cells (Tregs) before and after administration of anti‐TNF‐α therapy in CD. Methods Eight patients with active CD who had received anti‐TNF‐α antibodies were enrolled. Treatment responses were followed by physical examination and Crohn's disease activity index (CDAI) scoring before and 2 weeks after the initial administration of anti‐TNF‐α antibodies. Peripheral blood samples were collected before and 2 weeks after treatment. White blood cell count and serum levels of C‐reactive protein (CRP) and albumin were measured. FoxP3+ expression and CD127− Tregs were measured by fluorescence activated cell sorting (FACS) analysis of whole blood samples. Results Median values of CDAI decreased significantly after treatment. The proportion of FoxP3+ Tregs increased significantly after treatment. There was a significant negative correlation between ΔCD127− Tregs and Δlymphocyte. Conclusions Anti‐TNF‐α therapy would enhance Tregs, which may account for the mechanism underlying the positive effect of the anti‐TNF‐α treatment in CD patients.
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- 2020
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8. 3D cell sheets formed via cell-driven buckling-delamination of patterned thin films
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Tomoko Gowa Oyama, Kotaro Oyama, Hiromi Miyoshi, and Mitsumasa Taguchi
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Thin films ,Ion beams ,Polylactic acid ,Buckling ,Wrinkling ,3D cell sheets ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
Complex geometries such as folds and protrusions in various organs are formed by the wrinkling/buckling of flat epithelial sheets. This morphogenesis is considered to be triggered by mechanical instabilities between the epithelial sheet and the mesenchyme foundation, similar to that observed in non-living film-on-substrate structures. Here, we report a film-on-substrate cell culture system (FoSS), in which the cells can induce wrinkling and buckling-delamination of the surface layer from the foundation. Ion beam irradiation on polylactic acid (PLA) produced three layers: a crosslinked/carbonized surface, a decomposed middle layer that undergoes solation under the cell culture condition, and a foundation. This system was realized by controlling the three-dimensional (3D) distributions of scission/crosslinking probabilities in PLA. Madin-Darby canine kidney epithelial cells adhered well to the surface layer of FoSS. Cellular forces caused the layer to become wrinkled and subsequently delaminated as a thin film (~165 nm) from the foundation. The cell population then crumpled the peeled films, and within 48 h formed 3D cell sheets with folds and protrusions depending on patterns pre-set on the FoSS. FoSS can be utilized to produce in vitro models of 3D morphogenesis and 3D cell sheets that are currently in demand for tissue engineering and regenerative medicine.
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- 2021
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9. Successful Ascending to Descending Aortic Bypass and Endovascular Embolisation of a Late Pseudoaneurysm Following Patch Aortoplasty for Coarctation of the Aorta
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Takeshi Kamada, Ryoichi Tanaka, Tomoyuki Iwase, Kotaro Oyama, and Hajime Kin
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Ascending to descending aortic bypass ,Coarctation of the aorta ,Endovascular embolisation ,Open surgery ,Pseudoaneurysm ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 ,Surgery ,RD1-811 - Abstract
Introduction: A late aortic aneurysm at the site of previous open surgery for coarctation of the aorta (CoA) is a life threatening complication. Several strategies have been reported, however, these strategies have issues. This is the report of a case involving successful ascending to descending aortic bypass concomitant with endovascular embolisation for a pseudoaneurysm. Report: The patient was a 23 year old man with a history of patch aortoplasty for coarctation of the aorta (CoA) via a left thoracotomy and patch closure of a ventricular septal defect. Enhanced computed tomography (CT) angiography performed in 2014 revealed a pseudoaneurysm at the site of the previous patch aortoplasty. CT also revealed a hypoplastic and severely kinked aortic arch that made it difficult to perform conventional thoracic endovascular aortic repair for this aneurysm. Therefore in order to prevent rupture, a combination of ascending to descending aortic bypass and endovascular embolisation using Amplatzer vascular plugs and coils was employed. Transection of the aortic arch and transposition of the left subclavian artery were performed to prevent antegrade flow into the aneurysm. Discussion: The aneurysm was successfully excluded without complications. CT performed three years after the operation showed that the pseudoaneurysm had shrunk completely. Extra-anatomic bypass concomitant with endovascular embolisation for a late coarctation patched site aneurysm might be an alternative strategy that should be carefully considered in specific cases.
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- 2020
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10. Synthesis of Small Peptide Nanogels Using Radiation Crosslinking as a Platform for Nano-Imaging Agents for Pancreatic Cancer Diagnosis
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Atsushi Kimura, Tadashi Arai, Miho Ueno, Kotaro Oyama, Hao Yu, Shinichi Yamashita, Yudai Otome, and Mitsumasa Taguchi
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peptide ,nanogel ,radiation crosslinking ,γ-rays ,pancreatic cancer diagnosis ,nanotechnology ,Pharmacy and materia medica ,RS1-441 - Abstract
Nanoparticle-based drug delivery systems (DDS) have been developed as effective diagnostic and low-dose imaging agents. Nano-imaging agents with particles greater than 100 nm are difficult to accumulate in pancreatic cancer cells, making high-intensity imaging of pancreatic cancer challenging. Peptides composed of histidine and glycine were designed and synthesized. Additionally, aqueous peptide solutions were irradiated with γ-rays to produce peptide nanogels with an average size of 25–53 nm. The mechanisms underlying radiation-mediated peptide crosslinking were investigated by simulating peptide particle formation based on rate constants. The rate constants for reactions between peptides and reactive species produced by water radiolysis were measured using pulse radiolysis. HGGGHGGGH (H9, H—histidine; G—glycine) particles exhibited a smaller size, as well as high formation yield, stability, and biodegradability. These particles were labeled with fluorescent dye to change their negative surface potential and enhance their accumulation in pancreatic cancer cells. Fluorescent-labeled H9 particles accumulated in PANC1 human pancreatic cancer cells, demonstrating that these particles are effective nano-imaging agents for intractable cancers.
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- 2022
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11. Thermal Activation of Thin Filaments in Striated Muscle
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Shuya Ishii, Kotaro Oyama, Seine A. Shintani, Fuyu Kobirumaki-Shimozawa, Shin’ichi Ishiwata, and Norio Fukuda
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actomyosin ,Ca2+ sensitivity ,cardiac muscle ,skeletal muscle ,temperature ,tropomyosin ,Physiology ,QP1-981 - Abstract
In skeletal and cardiac muscles, contraction is triggered by an increase in the intracellular Ca2+ concentration. During Ca2+ transients, Ca2+-binding to troponin C shifts the “on–off” equilibrium of the thin filament state toward the “on” sate, promoting actomyosin interaction. Likewise, recent studies have revealed that the thin filament state is under the influence of temperature; viz., an increase in temperature increases active force production. In this short review, we discuss the effects of temperature on the contractile performance of mammalian striated muscle at/around body temperature, focusing especially on the temperature-dependent shift of the “on–off” equilibrium of the thin filament state.
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- 2020
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12. A Radiation-Crosslinked Gelatin Hydrogel That Promotes Tissue Incorporation of an Expanded Polytetrafluoroethylene Vascular Graft in Rats
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Sohei Matsuura, Toshio Takayama, Tomoko G. Oyama, Kotaro Oyama, Mitsumasa Taguchi, Takashi Endo, Takafumi Akai, Toshihiko Isaji, and Katsuyuki Hoshina
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expanded polytetrafluoroethylene ,vascular graft ,perigraft tissue incorporation ,gelatin hydrogel ,radiation-crosslinking ,Microbiology ,QR1-502 - Abstract
A prosthetic vascular graft that induces perigraft tissue incorporation may effectively prevent serious sequelae such as seroma formation and infection. Radiation-crosslinked gelatin hydrogel (RXgel) mimics the chemical and physical properties of the in vivo extracellular matrix and may facilitate wound healing by promoting tissue organization. Fibroblasts cultured on RXgel actively migrated into the gel for up to 7 days. RXgels of three different degrees of hardness (Rx[10], soft; Rx[15], middle; Rx[20], hard) were prepared, and small disc-like samples of RXgels were implanted into rats. In vitro and in vivo results indicated that Rx[10] was too soft to coat vascular grafts. Thus, expanded polytetrafluoroethylene (ePTFE) vascular grafts coated with RXgel were developed using Rx[15] and Rx[20] gels, and ring-shaped slices of the graft were implanted into rats. Alpha-smooth muscle actin (αSMA) and type III collagen (Col-III) levels were detected by immunohistochemistry. Immunohistochemical staining for αSMA and Col-III demonstrated that RXgel-coated vascular grafts induced more granulation tissue than non-coated grafts on days 14 and 28 after implantation. RXgel-coated ePTFE vascular grafts may provide a solution for patients by reducing poor perigraft tissue incorporation.
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- 2021
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13. Radiation Crosslinked Smart Peptide Nanoparticles: A New Platform for Tumor Imaging
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Atsushi Kimura, Miho Ueno, Tadashi Arai, Kotaro Oyama, and Mitsumasa Taguchi
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peptide ,nanoparticle ,radiation crosslinking ,γ-rays ,tumor diagnostics ,Chemistry ,QD1-999 - Abstract
Nanoparticles have been employed to develop nanosensors and drug carriers that accumulate in tumors. Thus, it is necessary to control the particle size, surface potential, and biodegradability of these nanoparticles for effective tumor accumulation and safe medical application. In this study, to form a nanoparticle platform suitable for diagnostic and drug delivery system (DDS) applications, peptides composed of aromatic amino acid residues were designed and synthesized based on the radiation crosslinking mechanism of proteins. The peptide nanoparticles, which were produced by γ-ray irradiation, displayed a positive surface potential, maintained biodegradability, and were stable in water and phosphoric buffer solution during actual diagnosis. The surface potential of the peptide nanoparticles could be changed to negative by using a fluorescent labeling reagent, so that the fluorescent-labeled peptide nanoparticles were uptaken by HeLa cells. The radiation-crosslinked nanoparticles can be applied as a platform for tumor-targeting diagnostics and DDS therapy.
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- 2021
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14. Real-Time In Vivo Imaging of Mouse Left Ventricle Reveals Fluctuating Movements of the Intercalated Discs
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Fuyu Kobirumaki-Shimozawa, Tomohiro Nakanishi, Togo Shimozawa, Takako Terui, Kotaro Oyama, Jia Li, William E. Louch, Shin’ichi Ishiwata, and Norio Fukuda
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myocardium ,gap junction ,action potential ,heart ,Chemistry ,QD1-999 - Abstract
Myocardial contraction is initiated by action potential propagation through the conduction system of the heart. It has been thought that connexin 43 in the gap junctions (GJ) within the intercalated disc (ID) provides direct electric connectivity between cardiomyocytes (electronic conduction). However, recent studies challenge this view by providing evidence that the mechanosensitive cardiac sodium channels Nav1.5 localized in perinexii at the GJ edge play an important role in spreading action potentials between neighboring cells (ephaptic conduction). In the present study, we performed real-time confocal imaging of the CellMask-stained ID in the living mouse heart in vivo. We found that the ID structure was not rigid. Instead, we observed marked flexing of the ID during propagation of contraction from cell to cell. The variation in ID length was between ~30 and ~42 μm (i.e., magnitude of change, ~30%). In contrast, tracking of α-actinin-AcGFP revealed a comparatively small change in the lateral dimension of the transitional junction near the ID (i.e., magnitude of change, ~20%). The present findings suggest that, when the heart is at work, mechanostress across the perinexii may activate Nav1.5 by promoting ephaptic conduction in coordination with electronic conduction, and, thereby, efficiently transmitting excitation-contraction coupling between cardiomyocytes.
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- 2020
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15. Development of Advanced Biodevices Using Quantum Beam Microfabrication Technology
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Tomoko G. Oyama, Atsushi Kimura, Naotsugu Nagasawa, Kotaro Oyama, and Mitsumasa Taguchi
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biodevice ,hydrogel ,crosslinking ,microfabrication ,poly(l-lactic acid) ,protein ,polydimethylsiloxane ,Technology ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Biodevices with engineered micro- and nanostructures are strongly needed for advancements in medical technology such as regenerative medicine, drug discovery, diagnostic reagents, and drug delivery to secure high quality of life. The authors produced functional biocompatible plastics and hydrogels with physical and chemical properties and surface microscopic shapes that can be freely controlled in three dimensions during the production process using the superior properties of quantum beams. Nanostructures on a biocompatible poly(L-lactic acid) surface were fabricated using a focused ion beam. Soft hydrogels based on polysaccharides were micro-fabricated using a focused proton beam. Gelatin hydrogels were fabricated using γ-rays and electron beam, and their microstructures and stiffnesses were controlled for biological applications. HeLa cells proliferated three-dimensionally on the radiation-crosslinked gelatin hydrogels and, furthermore, their shapes can be controlled by the micro-fabricated surface of the hydrogel. Long-lasting hydrophilic concave structures were fabricated on the surface of silicone by radiation-induced crosslinking and oxidation. The demonstrated advanced biodevices have potential applications in three-dimensional cell culture, gene expression control, stem cell differentiation induction/suppression, cell aggregation into arbitrary shapes, tissue culture, and individual diagnosis in the medical field.
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- 2020
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16. Transcatheter Coil Embolization of Single Coronary Artery Fistula Using the Occlusion Test
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Shin Takahashi, Yurie Takizawa, Satoshi Nakano, Junichi Koizumi, and Kotaro Oyama
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Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
The case of a patient in whom hemodynamic and electrocardiographic studies using the occlusion test for coronary artery fistulas (CAF) were safely performed prior to catheter embolization is reported. A 1-year-old girl had a separate right coronary artery arising from a left single coronary artery that formed a significant coronary artery fistula to the right ventricle. Coronary steal by the large coronary artery fistula narrowed the left coronary artery. The right coronary artery branches could not be clearly identified due to an overlap with the fistula. Due to the long porous CAF, embolic procedures could cause serious complications. We confirmed the safety by performing an occlusion test of the CAF’s proximal blood vessels. Following total occlusion of the CAF for 10 minutes, pulmonary arterial pressure and aortic blood pressure were not significantly changed. No bradycardia, atrioventricular block, or ST changes were observed. Coil embolization treatment was performed safely. For patients with long distal CAF complicated with a single coronary artery, myocardial ischemia and conduction system disorders can be identified by performing the occlusion test before embolization.
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- 2018
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17. Myosin and tropomyosin--troponin complementarily regulate thermal activation of muscles.
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Shuya Ishii, Kotaro Oyama, Fuyu Kobirumaki-Shimozawa, Tomohiro Nakanishi, Naoya Nakahara, Madoka Suzuki, Shin'ichi Ishiwata, and Norio Fukuda
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MYOSIN , *TROPONIN , *TROPOMYOSINS , *STRIATED muscle , *BODY temperature - Abstract
Contraction of striated muscles is initiated by an increase in cytosolic Ca2+ concentration, which is regulated by tropomyosin and troponin acting on actin filaments at the sarcomere level. Namely, Ca2+-binding to troponin C shifts the "on--off" equilibrium of the thin filament state toward the "on" state, promoting actomyosin interaction; likewise, an increase in temperature to within the body temperature range shifts the equilibrium to the on state, even in the absence of Ca2+. Here, we investigated the temperature dependence of sarcomere shortening along isolated fast skeletal myofibrils using optical heating microscopy. Rapid heating (25 to 41.5°C) within 2 s induced reversible sarcomere shortening in relaxing solution. Further, we investigated the temperature-dependence of the sliding velocity of reconstituted fast skeletal or cardiac thin filaments on fast skeletal or β-cardiac myosin in an in vitro motility assay within the body temperature range.We found that (a) with fast skeletal thin filaments on fast skeletal myosin, the temperature dependence was comparable to that obtained for sarcomere shortening in fast skeletal myofibrils (Q10 -8), (b) both types of thin filaments started to slide at lower temperatures on fast skeletal myosin than on β-cardiac myosin, and (c) cardiac thin filaments slid at lower temperatures compared with fast skeletal thin filaments on either type of myosin. Therefore, the mammalian striated muscle may be finetuned to contract efficiently via complementary regulation of myosin and tropomyosin--troponin within the body temperature range, depending on the physiological demands of various circumstances. [ABSTRACT FROM AUTHOR]
- Published
- 2023
18. Opto-thermal technologies for microscopic analysis of cellular temperature-sensing systems
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Madoka Suzuki, Shuya Ishii, and Kotaro Oyama
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Materials science ,Temperature sensing ,Structural Biology ,Thermal ,Biophysics ,Molecular motor ,Cellular functions ,Cellular level ,Biological system ,Molecular Biology - Abstract
Could enzymatic activities and their cooperative functions act as cellular temperature-sensing systems? This review introduces recent opto-thermal technologies for microscopic analyses of various types of cellular temperature-sensing system. Optical microheating technologies have been developed for local and rapid temperature manipulations at the cellular level. Advanced luminescent thermometers visualize the dynamics of cellular local temperature in space and time during microheating. An optical heater and thermometer can be combined into one smart nanomaterial that demonstrates hybrid function. These technologies have revealed a variety of cellular responses to spatial and temporal changes in temperature. Spatial temperature gradients cause asymmetric deformations during mitosis and neurite outgrowth. Rapid changes in temperature causes imbalance of intracellular Ca2+ homeostasis and membrane potential. Among those responses, heat-induced muscle contractions are highlighted. It is also demonstrated that the short-term heating hyperactivates molecular motors to exceed their maximal activities at optimal temperatures. We discuss future prospects for opto-thermal manipulation of cellular functions and contributions to obtain a deeper understanding of the mechanisms of cellular temperature-sensing systems.
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- 2021
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19. Microscopic Temperature Control Reveals Cooperative Regulation of Actin–Myosin Interaction by Drebrin E
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Shin'ichi Ishiwata, Kotaro Oyama, Hiroyuki Ogawa, Makito Miyazaki, Madoka Suzuki, Yuki Kawamura, Shuya Ishii, and Hiroaki Kubota
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heat pulse ,Motility ,Bioengineering ,actin-binding protein ,macromolecular substances ,Myosins ,nanofilament regulation ,Protein filament ,temperature imaging ,Myosin ,motility assay ,Molecular motor ,Animals ,General Materials Science ,Actin-binding protein ,Cytoskeleton ,Actin ,biology ,Chemistry ,Mechanical Engineering ,Neuropeptides ,Temperature ,cytoskeleton ,General Chemistry ,Condensed Matter Physics ,Actins ,molecular motor ,biology.protein ,Biophysics ,Intracellular - Abstract
Drebrin E is a regulatory protein of intracellular force produced by actomyosin complexes, that is, myosin molecular motors interacting with actin filaments. The expression level of drebrin E in nerve cells decreases as the animal grows, suggesting its pivotal but unclarified role in neuronal development. Here, by applying the microscopic heat pulse method to actomyosin motility assay, the regulatory mechanism is examined from the room temperature up to 37 °C without a thermal denaturing of proteins. We show that the inhibition of actomyosin motility by drebrin E is eliminated immediately and reversibly during heating and depends on drebrin E concentration. The direct observation of quantum dot-labeled drebrin E implies its stable binding to actin filaments during the heat-induced sliding. Our results suggest that drebrin E allosterically modifies the actin filament structure to regulate cooperatively the actomyosin activity at the maintained in vivo body temperature., 胎児の神経を形作る仕組みは精密な温度センサー --母体の体温維持が神経の成熟に重要であることを示唆--. 京都大学プレスリリース. 2021-11-10.
- Published
- 2021
20. Opto-thermal technologies for microscopic analysis of cellular temperature-sensing systems
- Author
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Kotaro, Oyama, Shuya, Ishii, and Suzuki, Madoka
- Abstract
Could enzymatic activities and their cooperative functions act as cellular temperature-sensing systems? This review introduces recent opto-thermal technologies for microscopic analyses of various types of cellular temperature-sensing system. Optical microheating technologies have been developed for local and rapid temperature manipulations at the cellular level. Advanced luminescent thermometers visualize the dynamics of cellular local temperature in space and time during microheating. An optical heater and thermometer can be combined into one smart nanomaterial that demonstrates hybrid function. These technologies have revealed a variety of cellular responses to spatial and temporal changes in temperature. Spatial temperature gradients cause asymmetric deformations during mitosis and neurite outgrowth. Rapid changes in temperature causes imbalance of intracellular Ca2+ homeostasis and membrane potential. Among those responses, heat-induced muscle contractions are highlighted. It is also demonstrated that the short-term heating hyperactivates molecular motors to exceed their maximal activities at optimal temperatures. We discuss future prospects for opto-thermal manipulation of cellular functions and contributions to obtain a deeper understanding of the mechanisms of cellular temperature-sensing systems.
- Published
- 2021
21. Early Ventricular Septal Defect Closure Prevents the Progression of Aortic Regurgitation: A Long-Term Follow-Up Study
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Hirofumi Saiki, Shin Takahashi, Kotaro Oyama, and Genichiro Sotodate
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Heart Septal Defects, Ventricular ,congenital, hereditary, and neonatal diseases and abnormalities ,medicine.medical_specialty ,medicine.medical_treatment ,Aortic Valve Insufficiency ,030204 cardiovascular system & hematology ,03 medical and health sciences ,0302 clinical medicine ,Aortic valve replacement ,Interquartile range ,Internal medicine ,medicine ,Humans ,Child ,Retrospective Studies ,Aortic Valve Prolapse ,business.industry ,Infant ,Retrospective cohort study ,Odds ratio ,Vascular surgery ,medicine.disease ,Confidence interval ,Cardiac surgery ,Aortic valvuloplasty ,Treatment Outcome ,030228 respiratory system ,Pediatrics, Perinatology and Child Health ,Cardiology ,Cardiology and Cardiovascular Medicine ,business ,Follow-Up Studies - Abstract
According to current short-term evidence, ventricular septal defect (VSD) closure should be performed as early as possible after aortic regurgitation (AR) diagnosis in pediatric patients to prevent AR progression. However, long-term follow-up data are lacking. Therefore, our aim was to evaluate the long-term follow-up (≥ 10 years) of patients who underwent VSD closure as early as possible after AR diagnosis and to evaluate whether early VSD closure prevents progression of AR. This was a retrospective cohort study of 42 patients with VSD and AR who had undergone VSD closure at a median age of 2.9 years, with a median waiting period from AR diagnosis to VSD closure of 3.4 months and follow-up of a median 13.1 years (interquartile range 10.0-15.8 years). The preoperative degree of AR was trivial in 25 patients, mild in 15, and moderate in 2. Of the 33 patients followed up for ≥ 10 years, none required aortic valve replacement and there was no incidence of mortality. The degree of AR improved or did not change, except in 1 patient. The size of the VSD (odds ratio [OR] 0.85; 95% confidence interval [CI] 0.62-1.18; p = 0.33), time from diagnosis to surgery (OR 1.00; 95% CI 1.000-1.001; p = 0.657), and age at the time of surgery (OR 1.00; 95% CI 0.998-1.004; p = 0.452) were not predictive of persistent postoperative AR. Therefore, VSD closure performed as early as possible after AR diagnosis could successfully prevent AR progression in patients with less than moderate preoperative AR, eliminating the need for aortic valve replacement and valvuloplasty.
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- 2021
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22. GNAO1 mutation-related severe involuntary movements treated with gabapentin
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Kenjiro Kosaki, Maya Asami, Akimune Fukushima, Kotaro Oyama, Kanako Mizuma, Toshiki Takenouchi, Hisato Suzuki, Manami Akasaka, Kayono Yamamoto, Atsushi Kamei, Jun Ito, Sachiko Tanifuji, Tomoko Uehara, and Tomoharu Tokutomi
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Movement disorders ,Gabapentin ,business.industry ,General Medicine ,medicine.disease ,GNAO1 ,03 medical and health sciences ,0302 clinical medicine ,Developmental Neuroscience ,Intensive care ,Anesthesia ,Pediatrics, Perinatology and Child Health ,medicine ,Midazolam ,Neurology (clinical) ,Global developmental delay ,medicine.symptom ,business ,Rhabdomyolysis ,030217 neurology & neurosurgery ,Exome sequencing ,medicine.drug - Abstract
Background Mutations in GNAO1 typically result in neurodevelopmental disorders, including involuntary movements. They may be improved using calcium-channel modulators. Case The patient visited our hospital at age 2 years because of moderate global developmental delay. Her intermittent, generalized involuntary movements started at age 8 years. A de novo GNAO1 mutation, NM_020988.2:c.626G > A, (p.Arg209Cys), was identified by whole exome sequencing. At age 9 years, she experienced severe, intermittent involuntary movements, which led to rhabdomyolysis. She needed intensive care with administration of midazolam, dantrolene sodium hydrate, and plasma exchange. We started treating her with gabapentin (GBP), after which she recovered completely. At age 11 years, she developed continuous, generalized involuntary movements. This prompted us to increase the GBP dose, which again resolved the involuntary movements completely. Conclusion In the case of movement disorders associated with GNAO1 mutations, GBP treatment may be attempted before more invasive procedures are performed.
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- 2021
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23. Family-centered shared decision-making in choosing modalities for renal replacement therapy in a pediatric patient with malignant disease
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Akira Takada, Ken Ishikawa, Kotaro Oyama, Mikiya Endo, Katsue Kikuchi, Chinatsu Onodera, Yoshiko Asakura, Hiromi Furukawa, Shoko Miura, Saeko Nishimi, Megumi Kobayashi, Hiroshi Sugawara, Takaya Abe, Shizuka Abe, Hisae Tachibana, and Daishi Hirai
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medicine.medical_specialty ,Pediatric patient ,Modalities ,business.industry ,medicine.medical_treatment ,medicine ,Renal replacement therapy ,Intensive care medicine ,business ,End-stage kidney disease ,Malignant disease - Published
- 2021
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24. Adult case of tetralogy of Fallot associated with atrioventricular septal defect
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Kotaro Oyama, Keisuke Sato, Shigeto Tsuji, Junichi Koizumi, Hajime Kin, Akio Ikai, Masaki Nii, and Azuma Tabayashi
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Adult ,Pulmonary and Respiratory Medicine ,congenital, hereditary, and neonatal diseases and abnormalities ,medicine.medical_specialty ,Complete atrioventricular septal defect ,030204 cardiovascular system & hematology ,03 medical and health sciences ,0302 clinical medicine ,Cardiac magnetic resonance imaging ,Internal medicine ,Humans ,Medicine ,Straddling mitral valve ,cardiovascular diseases ,Atrioventricular Septal Defect ,Cardiac Surgical Procedures ,Tetralogy of Fallot ,medicine.diagnostic_test ,business.industry ,Heart Septal Defects ,General Medicine ,medicine.disease ,Shunt (medical) ,Cardiac surgery ,Treatment Outcome ,030228 respiratory system ,Cardiothoracic surgery ,cardiovascular system ,Cardiology ,Female ,Surgery ,Cardiology and Cardiovascular Medicine ,business - Abstract
The patient was a 28-year-old woman who was misdiagnosed with tetralogy of Fallot and straddling mitral valve after birth. She underwent a left modified Blalock-Taussig shunt at the age of 1 year. At age 28, she presented with fatigue and progressive cyanosis. Finally, she was diagnosed with tetralogy of Fallot and complete atrioventricular septal defect. To measure the exact biventricular volumes, we performed cardiac magnetic resonance imaging in addition to cardiac angiography and ensured adequate volume capacity. We eventually decided to perform biventricular repair. Her postoperative course was uneventful, and she returned to full-time work.
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- 2020
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25. Successful Ascending to Descending Aortic Bypass and Endovascular Embolisation of a Late Pseudoaneurysm Following Patch Aortoplasty for Coarctation of the Aorta
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Ryoichi Tanaka, Takeshi Kamada, Kotaro Oyama, Tomoyuki Iwase, and Hajime Kin
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Aortic arch ,lcsh:Diseases of the circulatory (Cardiovascular) system ,medicine.medical_specialty ,medicine.medical_treatment ,lcsh:Surgery ,Coarctation of the aorta ,Case Report ,Open surgery ,Pseudoaneurysm ,Aortic aneurysm ,Aneurysm ,medicine.artery ,Endovascular embolisation ,medicine ,Thoracotomy ,cardiovascular diseases ,medicine.diagnostic_test ,business.industry ,lcsh:RD1-811 ,medicine.disease ,Surgery ,lcsh:RC666-701 ,Angiography ,cardiovascular system ,Ascending to descending aortic bypass ,Cardiology and Cardiovascular Medicine ,Complication ,business - Abstract
Introduction A late aortic aneurysm at the site of previous open surgery for coarctation of the aorta (CoA) is a life threatening complication. Several strategies have been reported, however, these strategies have issues. This is the report of a case involving successful ascending to descending aortic bypass concomitant with endovascular embolisation for a pseudoaneurysm. Report The patient was a 23 year old man with a history of patch aortoplasty for coarctation of the aorta (CoA) via a left thoracotomy and patch closure of a ventricular septal defect. Enhanced computed tomography (CT) angiography performed in 2014 revealed a pseudoaneurysm at the site of the previous patch aortoplasty. CT also revealed a hypoplastic and severely kinked aortic arch that made it difficult to perform conventional thoracic endovascular aortic repair for this aneurysm. Therefore in order to prevent rupture, a combination of ascending to descending aortic bypass and endovascular embolisation using Amplatzer vascular plugs and coils was employed. Transection of the aortic arch and transposition of the left subclavian artery were performed to prevent antegrade flow into the aneurysm. Discussion The aneurysm was successfully excluded without complications. CT performed three years after the operation showed that the pseudoaneurysm had shrunk completely. Extra-anatomic bypass concomitant with endovascular embolisation for a late coarctation patched site aneurysm might be an alternative strategy that should be carefully considered in specific cases., Highlights • A case of late coarctation patched site pseudoaneurysm is presented. • Ascending to descending aortic bypass was performed successfully. • The aneurysm was treated successfully by endovascular embolisation. • Follow up computed tomography showed that the pseudoaneurysm had shrunk completely. • This approach might be an alternative strategy that should be carefully considered.
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- 2020
26. Effect of Minocycline Pleurodesis in Infants With Refractory Chylothorax After Palliative Surgery for Complex Congenital Heart Disease
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Kanchi Saito, Hirofumi Saiki, Shigekuni Tsuchiya, Yurie Takizawa, Akira Sato, Takuya Goto, Yukiko Toya, Atsushi Matsumoto, Junichi Koizumi, Kotaro Oyama, and Manami Akasaka
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General Engineering - Published
- 2022
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27. Mice with R2509C-RYR1 mutation exhibit dysfunctional Ca2+ dynamics in primary skeletal myocytes
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Yoshitaka Tsuboi, Kotaro Oyama, Fuyu Kobirumaki-Shimozawa, Takashi Murayama, Nagomi Kurebayashi, Toshiaki Tachibana, Yoshinobu Manome, Emi Kikuchi, Satoru Noguchi, Takayoshi Inoue, Yukiko U. Inoue, Ichizo Nishino, Shuichi Mori, Ryosuke Ishida, Hiroyuki Kagechika, Madoka Suzuki, Norio Fukuda, and Toshiko Yamazawa
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Mice ,Physiology ,Muscle Fibers, Skeletal ,Mutation ,Animals ,Calcium ,Ryanodine Receptor Calcium Release Channel ,Malignant Hyperthermia ,Muscle, Skeletal - Abstract
Type 1 ryanodine receptor (RYR1) is a Ca2+ release channel in the sarcoplasmic reticulum (SR) of the skeletal muscle and plays a critical role in excitation–contraction coupling. Mutations in RYR1 cause severe muscle diseases, such as malignant hyperthermia, a disorder of Ca2+-induced Ca2+ release (CICR) through RYR1 from the SR. We recently reported that volatile anesthetics induce malignant hyperthermia (MH)-like episodes through enhanced CICR in heterozygous R2509C-RYR1 mice. However, the characterization of Ca2+ dynamics has yet to be investigated in skeletal muscle cells from homozygous mice because these animals die in utero. In the present study, we generated primary cultured skeletal myocytes from R2509C-RYR1 mice. No differences in cellular morphology were detected between wild type (WT) and mutant myocytes. Spontaneous Ca2+ transients and cellular contractions occurred in WT and heterozygous myocytes, but not in homozygous myocytes. Electron microscopic observation revealed that the sarcomere length was shortened to ∼1.7 µm in homozygous myocytes, as compared to ∼2.2 and ∼2.3 µm in WT and heterozygous myocytes, respectively. Consistently, the resting intracellular Ca2+ concentration was higher in homozygous myocytes than in WT or heterozygous myocytes, which may be coupled with a reduced Ca2+ concentration in the SR. Finally, using infrared laser-based microheating, we found that heterozygous myocytes showed larger heat-induced Ca2+ transients than WT myocytes. Our findings suggest that the R2509C mutation in RYR1 causes dysfunctional Ca2+ dynamics in a mutant-gene dose-dependent manner in the skeletal muscles, in turn provoking MH-like episodes and embryonic lethality in heterozygous and homozygous mice, respectively.
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- 2022
28. 細胞に立体構造を作らせる!細胞の小さな力で変形する薄膜の開発
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Tomoko, Oyama, Kotaro, Oyama, and Mitsumasa, Taguchi
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私たちの体の中には、臓器が正常に機能するに不可欠なヒダや突起が存在する。しかし、細胞を従来から用いられている硬いプラスチック皿で培養しても平面状に広がるだけで、体の中の立体構造がいかにして形作られるのか、未だ詳細が分かっていない。そこで細胞の力に注目し、細胞が接着面を引っ張る小さな力でも変形するフレキシブル薄膜をイオンビーム加工技術で開発した。薄膜の厚みやパターンの制御により、培養細胞に薄膜を変形させて、ヒダや突起構造を形作らせることに成功した。, QST高崎サイエンスフェスタ2021
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- 2021
29. Dysfunctional Ca2+ dynamics in primary skeletal myocytes from R2509C-RYR1 mice
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Yoshitaka Tsuboi, Kotaro Oyama, Fuyu Kobirumaki-Shimozawa, Takashi Murayama, Nagomi Kurebayashi, Toshiaki Tachibana, Yoshinobu Manome, Emi Kikuchi, Madoka Suzuki, Norio Fukuda, and Toshiko Yamazawa
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Biophysics - Published
- 2023
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30. イオンビーム加工技術による、細胞に立体構造を作らせる薄膜の開発
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Tomoko, Oyama, Kotaro, Oyama, and Mitsumasa, Taguchi
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ディッシュ上で培養した細胞は平面状に広がるだけで、生体内の細胞がどのようにして立体構造を形作るのか、未だによく分かっていない。我々は、細胞の力で変形する培養用薄膜があれば、細胞が立体構造を作るのではないかと考えた。イオンビームがポリ乳酸中に誘起する分解と架橋の割合を空間的に制御することで、細胞の小さな力で剥離・変形可能な薄膜を開発し、細胞にヒダや突起を作らせて3次元細胞シートを得ることに成功した。, 日本原子力学会 関東・甲越支部 第20回 若手研究者・技術者発表討論会
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- 2021
31. ラット移植モデルを用いた放射線架橋ゼラチンハイドロゲル被覆ePTFE人工血管器質化効果の検討
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Tomoko, Oyama, Kotaro, Oyama, and Mitsumasa, Taguchi
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人工血管移植後の漿液腫は、入院期間の延長や再手術のみならず感染合併により最悪肢切断に至る重篤な合併症である。移植後の周囲器質化を促進させ漿液腫を予防するために、ガンマ線架橋ゼラチンハイドロゲル(RXゲル)を人工血管外側に被覆した。RXゲルは細胞外マトリックスに極めて近い組成・物性を有し、ゲル硬度や含水度を制御することができる。RXゲル被覆人工血管を動物に移植して評価したところ、従来の人工血管に比べ器質化が促進されていることが分かったので報告する。, 第62回日本脈管学会総会
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- 2021
32. Synchrony of sarcomeric movement regulates left ventricular pump function in the in vivo beating mouse heart
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William E. Louch, Norio Fukuda, Tomohiro Nakanishi, Shunsuke Baba, Takako Terui, Kotaro Oyama, Fuyu Kobirumaki-Shimozawa, Shin'ichi Ishiwata, Jia Li, and Togo Shimozawa
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Sarcomeres ,medicine.medical_specialty ,Physiology ,Chemistry ,Diastole ,Cardiac muscle ,Skeletal muscle ,Actinin ,Sarcomere ,Mice ,medicine.anatomical_structure ,Myofibrils ,Ventricle ,Internal medicine ,medicine ,Cardiology ,Animals ,Myocyte ,Myocytes, Cardiac ,Myofibril ,Muscle Contraction - Abstract
Sarcomeric contraction in cardiomyocytes serves as the basis for the heart’s pump functions. It has generally been considered that in cardiac muscle as well as in skeletal muscle, sarcomeres equally contribute to myofibrillar dynamics in myocytes at varying loads by producing similar levels of active and passive force. In the present study, we expressed α-actinin–AcGFP in Z-disks to analyze dynamic behaviors of sequentially connected individual sarcomeres along a myofibril in a left ventricular (LV) myocyte of the in vivo beating mouse heart. To quantify the magnitude of the contribution of individual sarcomeres to myofibrillar dynamics, we introduced the novel parameter “contribution index” (CI) to measure the synchrony in movements between a sarcomere and a myofibril (from −1 [complete asynchrony] to 1 [complete synchrony]). First, CI varied markedly between sarcomeres, with an average value of ∼0.3 during normal systole. Second, when the movements between adjacent sarcomeres were asynchronous (CI < 0), a sarcomere and the ones next to the adjacent sarcomeres and farther away moved in synchrony (CI > 0) along a myofibril. Third, when difference in LV pressure in diastole and systole (ΔLVP) was lowered to
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- 2021
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33. 3D cell sheets formed via cell-driven buckling-delamination of patterned thin films
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Mitsumasa Taguchi, Tomoko Gowa Oyama, Hiromi Miyoshi, and Kotaro Oyama
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education.field_of_study ,Materials science ,Buckling ,Mechanical Engineering ,Thin films ,Delamination ,Population ,Morphogenesis ,Wrinkling ,Polylactic acid ,chemistry.chemical_compound ,chemistry ,Tissue engineering ,Mechanics of Materials ,Ion beams ,3D cell sheets ,TA401-492 ,General Materials Science ,Surface layer ,Composite material ,Thin film ,education ,Layer (electronics) ,Materials of engineering and construction. Mechanics of materials - Abstract
Complex geometries such as folds and protrusions in various organs are formed by the wrinkling/buckling of flat epithelial sheets. This morphogenesis is considered to be triggered by mechanical instabilities between the epithelial sheet and the mesenchyme foundation, similar to that observed in non-living film-on-substrate structures. Here, we report a film-on-substrate cell culture system (FoSS), in which the cells can induce wrinkling and buckling-delamination of the surface layer from the foundation. Ion beam irradiation on polylactic acid (PLA) produced three layers: a crosslinked/carbonized surface, a decomposed middle layer that undergoes solation under the cell culture condition, and a foundation. This system was realized by controlling the three-dimensional (3D) distributions of scission/crosslinking probabilities in PLA. Madin-Darby canine kidney epithelial cells adhered well to the surface layer of FoSS. Cellular forces caused the layer to become wrinkled and subsequently delaminated as a thin film (~165 nm) from the foundation. The cell population then crumpled the peeled films, and within 48 h formed 3D cell sheets with folds and protrusions depending on patterns pre-set on the FoSS. FoSS can be utilized to produce in vitro models of 3D morphogenesis and 3D cell sheets that are currently in demand for tissue engineering and regenerative medicine.
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- 2021
34. Predictive ability of neonatal illness severity scores for early death in extremely premature infants
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Nao Takashimizu, Genichiro Sotodate, Yukiko Toya, Kotaro Oyama, Yu Konishi, and Atsushi Matsumoto
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Pediatrics ,medicine.medical_specialty ,Perinatal care ,Gestational Age ,Early death ,macromolecular substances ,Severity of Illness Index ,03 medical and health sciences ,0302 clinical medicine ,Predictive Value of Tests ,Pregnancy ,Intensive Care Units, Neonatal ,030225 pediatrics ,Infant Mortality ,medicine ,Humans ,Illness severity ,030212 general & internal medicine ,Retrospective Studies ,Extremely premature ,business.industry ,Infant, Newborn ,Patient Acuity ,Infant ,Obstetrics and Gynecology ,Infant, Extremely Premature ,Pediatrics, Perinatology and Child Health ,Female ,business - Abstract
The predictive ability of neonatal illness severity scores for mortality or morbidity in extremely premature infants has not been extensively studied. We aimed to evaluate the ability of neonatal illness severity scores [Clinical Risk Index for Babies II (CRIB II), Score for Neonatal Acute Physiology II (SNAP-II), and SNAP-Perinatal Extension II (SNAPPE-II)] in predicting mortality and short-term morbidity of extremely premature infants.This retrospective study involved 171 infants with gestational age (GA) between 22 and 27 weeks who were admitted to the NICU during 2010-2017. Predictive ability of neonatal illness severity scores for mortality and short-term morbidity (bronchopulmonary dysplasia, retinopathy of prematurity, intraventricular hemorrhage, necrotizing enterocolitis, and gastrointestinal perforation) was assessed by comparing their area under the receiver operating characteristic curve.The overall mortality rate was 11.1%. Mortality at 23 weeks' gestation was higher than that at 24-27 weeks' gestation (The neonatal illness severity scores were excellent predictors of early death in extremely premature infants and might be useful for selecting extremely preterm infants who need intervention.
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- 2020
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35. Validity of a disposable catheter to drain urine overnight in neurogenic bladder
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Saeko Nishimi, Ken Ishikawa, Kotaro Oyama, Shigekuni Tsuchiya, Akira Takada, Hiromi Furukawa, Chinatsu Onodera, Shoichi Chida, and Makoto Sasaki
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Male ,Swine ,Urine ,In Vitro Techniques ,Urinary Catheters ,030204 cardiovascular system & hematology ,Random Allocation ,03 medical and health sciences ,0302 clinical medicine ,030225 pediatrics ,Catheter drainage ,Animals ,Medicine ,In vitro study ,Urinary Bladder, Neurogenic ,Disposable Equipment ,Cross-Over Studies ,business.industry ,In vitro experiment ,Clean Intermittent Catheterization ,Residual urine volume ,Catheter ,Anesthesia ,Urinary Tract Infections ,Pediatrics, Perinatology and Child Health ,Drainage ,Rabbits ,In vivo experiment ,Urinary Catheterization ,business - Abstract
Background Overnight catheter drainage (OCD) is introduced to avoid overdistention of the bladder at night-time when clean intermittent catheterization proves ineffective for daytime management of neurogenic bladder. We adopted OCD using disposable silicone no-balloon (DSnB) catheters, with the distal end outside the body opening into diapers. OCD using DSnB catheter, however, had risks of retrograde bacterial contamination. Therefore, in this study, the validity of equipping DSnB catheters with check valves to prevent retrograde bacterial contamination was examined. Methods For the in vitro study, excised saline-filled swine bladders were drained using DSnB catheters with or without check valves, and the time required for intravesical pressure to reach 5 cmH2 O was measured. For the in vivo study, in cross-over experiments comparing DSnB catheters with and without check valves, OCD using DSnB catheters for 10 h was performed in rabbits under analgesia. Bacterial growth from urine samples before and after OCD and residual urine volume were examined. Results For the in vitro experiment, the median drainage time was 368.2 s (range, 88-1,085 s) and 344.7 s (range, 28-840 s) with and without check valves, respectively (n = 6), which was not significantly different. For the in vivo experiment, in cross-over experiments (n = 8) new bacterial growth rates after OCD did not differ, and median residual urine volume was 17.1 mL (range, 0-75 mL) and 1.2 mL (range, 0-5 mL) with and without check valves, respectively (P = 0.055). Conclusions Installing a check valve in the DSnB catheter did not decrease new bacterial growth, while tending to increase residual urine volume. DSnB catheters without check valves appear to be better for continuous drainage of urine from bladder.
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- 2019
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36. Microscopic heat pulses activate cardiac thin filaments
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Shuya Ishii, Norio Fukuda, Madoka Suzuki, Seine A. Shintani, Takako Terui, Shin'ichi Ishiwata, Fuyu Kobirumaki-Shimozawa, Tomomi Arai, Kotaro Oyama, and Hideki Itoh
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Sarcomeres ,Hot Temperature ,Materials science ,Physiology ,chemistry.chemical_element ,macromolecular substances ,Myosins ,Temperature measurement ,Sarcomere ,Adenosine Triphosphate ,Myofibrils ,Animals ,Humans ,Irradiation ,Research Articles ,Actin ,Myocardium ,Communication ,Endoplasmic reticulum ,Heart ,Fluorescence ,Actins ,Troponin ,Coupling (electronics) ,Actin Cytoskeleton ,chemistry ,Biophysics ,Calcium ,Cattle ,sense organs ,Rabbits ,Europium - Abstract
Muscle fiber contraction involves chemical reactions and structural changes that are sensitive to temperature. Ishii et al. show that rapid heating causes cardiac thin filament sliding, and the data could indicate that thin filaments are partially activated during diastole at mammalian body temperature., During the excitation–contraction coupling of the heart, sarcomeres are activated via thin filament structural changes (i.e., from the “off” state to the “on” state) in response to a release of Ca2+ from the sarcoplasmic reticulum. This process involves chemical reactions that are highly dependent on ambient temperature; for example, catalytic activity of the actomyosin ATPase rises with increasing temperature. Here, we investigate the effects of rapid heating by focused infrared (IR) laser irradiation on the sliding of thin filaments reconstituted with human α-tropomyosin and bovine ventricular troponin in an in vitro motility assay. We perform high-precision analyses measuring temperature by the fluorescence intensity of rhodamine-phalloidin–labeled F-actin coupled with a fluorescent thermosensor sheet containing the temperature-sensitive dye Europium (III) thenoyltrifluoroacetonate trihydrate. This approach enables a shift in temperature from 25°C to ∼46°C within 0.2 s. We find that in the absence of Ca2+ and presence of ATP, IR laser irradiation elicits sliding movements of reconstituted thin filaments with a sliding velocity that increases as a function of temperature. The heating-induced acceleration of thin filament sliding likewise occurs in the presence of Ca2+ and ATP; however, the temperature dependence is more than twofold less pronounced. These findings could indicate that in the mammalian heart, the on–off equilibrium of the cardiac thin filament state is partially shifted toward the on state in diastole at physiological body temperature, enabling rapid and efficient myocardial dynamics in systole.
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- 2019
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37. Intrapulmonary artery septation for unilateral absence of the pulmonary artery
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Takuya Goto, Kotaro Oyama, Shigeto Tsuji, Hajime Kin, Tomoyuki Iwase, and Junichi Koizumi
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Pulmonary and Respiratory Medicine ,Male ,congenital, hereditary, and neonatal diseases and abnormalities ,medicine.medical_specialty ,Resuscitation ,030204 cardiovascular system & hematology ,Pulmonary Artery ,03 medical and health sciences ,0302 clinical medicine ,medicine.artery ,Internal medicine ,medicine ,Humans ,Blalock-Taussig Procedure ,Tetralogy of Fallot ,Absent pulmonary artery ,Multiple abnormalities ,business.industry ,Infant ,General Medicine ,Left pulmonary artery ,medicine.disease ,medicine.anatomical_structure ,Treatment Outcome ,030228 respiratory system ,Pulmonary artery ,Cardiology ,Surgery ,Cardiology and Cardiovascular Medicine ,business ,Shunt (electrical) ,Artery - Abstract
We describe a seven-month-old boy with tetralogy of Fallot and an absent left pulmonary artery. Due to the diminutive size of the left pulmonary artery, we performed a native tissue left pulmonary artery reconstruction and intrapulmonary artery septation procedure with a left modified Blalock-Taussig shunt. After confirming left pulmonary artery growth, the patient underwent tetralogy of Fallot repair, removal of septation patch, and division of the Blalock-Taussig shunt. Nine months post-surgery, we confirmed his balanced lung perfusion (R/L ratio 6:4). The intrapulmonary artery septation procedure would be suitable for both the resuscitation and reconstruction of the hypoplastic absent pulmonary artery.
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- 2021
38. Reliability of respiratory-triggered two-dimensional cine k-adaptive-t-autocalibrating reconstruction for Cartesian sampling for the assessment of biventricular volume and function in patients with repaired tetralogy of Fallot
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Tsuyoshi Sugawara, Hidenobu Takagi, Makoto Orii, Kotaro Oyama, Yurie Takizawa, Atsushi Nozaki, Satoshi Nakano, Martin A. Janich, Shin Takahashi, Jumpei Fujiwara, Hironobu Ueda, Peng Lai, and Kunihiro Yoshioka
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Adult ,Male ,medicine.medical_specialty ,Image quality ,Heart Ventricles ,Ventricular Dysfunction, Right ,030204 cardiovascular system & hematology ,030218 nuclear medicine & medical imaging ,law.invention ,Breath Holding ,03 medical and health sciences ,Ventricular Dysfunction, Left ,0302 clinical medicine ,Postoperative Complications ,Sampling (signal processing) ,law ,Internal medicine ,Image Interpretation, Computer-Assisted ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Cartesian coordinate system ,Respiratory system ,Tetralogy of Fallot ,Full Paper ,business.industry ,Reproducibility of Results ,Stroke Volume ,General Medicine ,Function (mathematics) ,Stroke volume ,medicine.disease ,Magnetic Resonance Imaging ,Cardiology ,Female ,business ,Volume (compression) - Abstract
Objective: To compare left ventricular (LV) and right ventricular (RV) volume, function, and image quality of a respiratory-triggered two-dimensional (2D)-cine k-adaptive-t-autocalibrating reconstruction for Cartesian sampling (2D kat-ARC) with those of the standard reference, namely, breath-hold 2D balanced steady-state free precession (2D SSFP), in patients with repaired tetralogy of Fallot (TOF). Methods: 30 patients (14 males, mean age 32.2 ± 13.9 years) underwent cardiac magnetic resonance, and 2D kat-ARC and 2D SSFP images were acquired on short-axis view. Biventricular end-diastolic volume (EDV) and end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), and LV mass (LVM) were analysed. Results: The 2D kat-ARC had significantly shorter scan time (35.2 ± 9.1 s vs 80.4 ± 16.7 s; p < 0.0001). Despite an analysis of image quality showed significant impairment using 2D kat-ARC compared to 2D SSFP cine (p < 0.0001), the two sequences demonstrated no significant difference in terms of biventricular EDV, LVESV, LVSV, LVEF, and LVM. However, the RVESV was overestimated for 2D kat-ARC compared with that for 2D SSFP (73.8 ± 43.2 ml vs 70.3 ± 44.5 ml, p = 0.0002) and the RVSV and RVEF were underestimated (RVSV = 46.2±20.5 ml vs 49.4 ± 20.4 ml, p = 0.0024; RVEF = 40.2±12.7% vs. 43.5±14.0%, p = 0.0002). Conclusion: Respiratory-triggered 2D kat-ARC cine is a reliable technique that could be used in the evaluation of LV volumes and function. Advances in knowledge: 2D cine kat-ARC is a reliable technique for the assessment LV volume and function in patients with repaired TOF.
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- 2021
39. 生体内環境を再現するタンパク質ゲルの開発
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Mitsumasa, Taguchi, Tomoko, Oyama, Kotaro, Oyama, and Atsushi, Kimura
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量子ビーム橋かけ技術を駆使してタンパク質をゲル化し、さらにその硬さや形状を制御する新技術を実現した。このゲルはタンパク質本来の生体適合性や生分解性を保持しており、硬さを軟組織全域で自在に調整でき、なおかつ表面に微小な凹凸構造を付与することもできる。生体内における細胞外マトリックスの化学的・物理的特性を再現したゲルの上では、ディッシュ上では見ることができない3次元的な細胞の姿や機能発現を見ることができる。, 第20回日本再生医療学会総会
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- 2021
40. Hydrostatic Pressure-Regulated Cellular Calcium Responses
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Akihisa Miyagawa, Minami Fukuchi, Hiroaki Mizuno, Kazuya Koumoto, Kotaro Oyama, and Gaku Fukuhara
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Chemistry ,Hydrostatic pressure ,02 engineering and technology ,Surfaces and Interfaces ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,law.invention ,Cell calcium ,law ,Electrochemistry ,Biophysics ,Hydrostatic Pressure ,Humans ,General Materials Science ,Calcium ,Hydrostatic equilibrium ,0210 nano-technology ,Spectral data ,Spectroscopy ,Calcium entry ,HeLa Cells - Abstract
Hydrostatic pressure control has attracted much attention and presents a still challenging objective from mechanobiological viewpoints. Herein, we reveal the calcium entry processes in HeLa cells by means of hydrostatic pressure spectroscopy. The steady-state fluorescence spectral data comprehensively elucidated the factors controlling the outcomes of the hydrostatic pressure-stimulated calcium entry behavior. The present work leads to a new perspective on ion regulations in living cells and an attractive alternative to conventional mechanostimuli.
- Published
- 2021
41. Turner Syndrome Associated With Refractory Seizures and Intellectual Disability: A Case Study
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Kotaro Oyama, Atsushi Kamei, Jun Ito, and Manami Akasaka
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Pediatrics ,medicine.medical_specialty ,g-band analysis ,030204 cardiovascular system & hematology ,Lamotrigine ,Short stature ,03 medical and health sciences ,Epilepsy ,0302 clinical medicine ,Intellectual disability ,Turner syndrome ,Genetics ,medicine ,Ictal ,Global developmental delay ,spikes shifting foci ,fluorescence in situ hybridization ,Valproic Acid ,business.industry ,General Engineering ,lamotrigine and valproic acid combination therapy ,medicine.disease ,neurodevelopmental disorder ,refractory seizure ,mosaicism ,Neurology ,intellectual disability ,unclassified epilepsy ,turner syndrome ,medicine.symptom ,business ,030217 neurology & neurosurgery ,medicine.drug - Abstract
Turner syndrome (TS) is the most frequent sex abnormality in women. The physical features include short stature, webbing of the neck, and gonadal dysgenesis. Typically, patients with Turner syndrome exhibit no intellectual disability, and a few cases of TS have been associated with epilepsy. Herein, we present a case of TS with intractable epilepsy. The patient presented with global developmental delay at the age of two and karyotyping revealed mosaicism [45, X/46, X del (X) (q21.1)]. At the age of seven, she had generalized tonic epilepsy as well as several focal-onset seizures. She developed daily seizures, which were refractory to several antiepileptic drugs. Interictal electroencephalography (EEG) revealed multifocal spikes, and ictal EEG revealed shifting foci. She visited our hospital at the age of 13. Her peripheral white blood cells G-band and fluorescence in situ hybridization (FISH) method chromosome with cheek swab examinations revealed 45, X. Her peripheral white blood cell mosaic pattern may have disappeared over time or become indetectable. We treated her with clobazam, and then lamotrigine and valproic acid combination therapy, which resulted in a reduction in the frequency of seizures by approximately 50%. Epilepsy and intellectual disability in this case may be due to the mosaic deletion at Xq21.1. Further analysis of similar cases may provide valuable information for effective therapeutic strategies.
- Published
- 2020
- Full Text
- View/download PDF
42. Collagen hydrogels with controllable combined cues of elasticity and topography to regulate cellular processes
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Fumiya Yoshida, Hiromi Miyoshi, Ryo Ishida, Mitsumasa Taguchi, Tomoko Gowa Oyama, Kotaro Oyama, Masashi Yamazaki, and Atsushi Kimura
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food.ingredient ,Surface Properties ,0206 medical engineering ,Biomedical Engineering ,Bioengineering ,Biocompatible Materials ,02 engineering and technology ,Cell morphology ,Gelatin ,Actin cytoskeleton organization ,Cell Physiological Phenomena ,Madin Darby Canine Kidney Cells ,Biomaterials ,Extracellular matrix ,chemistry.chemical_compound ,food ,Dogs ,Tissue engineering ,Collagen network ,Animals ,Humans ,Hydrolyzed collagen ,Cells, Cultured ,Chemistry ,Hydrogels ,021001 nanoscience & nanotechnology ,020601 biomedical engineering ,Elasticity ,Extracellular Matrix ,Rats ,Self-healing hydrogels ,Biophysics ,Collagen ,0210 nano-technology ,HeLa Cells - Abstract
The elasticity, topography, and chemical composition of cell culture substrates influence cell behavior. However, the cellular responses toin vivoextracellular matrix (ECM), a hydrogel of proteins (mainly collagen) and polysaccharides, remain unknown as there is no substrate that preserves the key features of native ECM. This study introduces novel collagen hydrogels that can combine elasticity, topography, and composition and reproduce the correlation between collagen concentration (C) and elastic modulus (E) in native ECM. A simple reagent-free method based on radiation-cross-linking altered ECM-derived collagen I and hydrolyzed collagen (gelatin or collagen peptide) solutions into hydrogels with tunable elastic moduli covering a broad range of soft tissues (E= 1-236 kPa) originating from the final collagen density in the hydrogels (C= 0.3%-14%) and precise microtopographies (⩾1 μm). The amino acid composition ratio was almost unchanged by this method, and the obtained collagen hydrogels maintained enzyme-mediated degradability. These collagen hydrogels enabled investigation of the responses of cell lines (fibroblasts, epithelial cells, and myoblasts) and primary cells (rat cardiomyocytes) to soft topographic cues such as thosein vivounder the positive correlation betweenCandE. These cells adhered directly to the collagen hydrogels and chose to stay atop or spontaneously migrate into them depending onE, that is, the density of the collagen network,C. We revealed that the cell morphology and actin cytoskeleton organization conformed to the topographic cues, even when they are as soft asin vivoECM. The stiffer microgrooves on collagen hydrogels aligned cells more effectively, except HeLa cells that underwent drastic changes in cell morphology. These collagen hydrogels may not only reducein vivoandin vitrocell behavioral disparity but also facilitate artificial ECM design to control cell function and fate for applications in tissue engineering and regenerative medicine.
- Published
- 2020
43. Increased Burden of Ion Channel Gene Variants Is Related to Distinct Phenotypes in Pediatric Patients With Left Ventricular Noncompaction
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Keiichi Hirono, Yukiko Hata, Nariaki Miyao, Mako Okabe, Shinya Takarada, Hideyuki Nakaoka, Keijiro Ibuki, Sayaka Ozawa, Hideki Origasa, Naoki Nishida, Fukiko Ichida, Atsuhito Takeda, Atsuya Shimabukuro, Chisato Akita, Daichi Fukumi, Eiki Nishihara, Etsuko Tsuda, Heima Sakaguchi, Hidekazu Ishida, Hideshi Tomita, Hiroaki Kise, Hiroki Nagamine, Hiroki Uchiyama, Hiromi Katayama, Hiroo Ooki, Hiroshi Nishikawa, Hiroshi Ono, Hisanori Sakazaki, Hitoshi Horigome, Jun Muneuchi, Jun Yoshimoto, Junpei Soumura, Masahiro Kamada, Kazushi Yasuda, Kazuyuki Ikeda, Keiji Yasuda, Kenichi Kurosaki, Kenji Mine, Kentaro Ueno, Kiyohiro Takigiku, Kiyoshi Ogawa, Kotaro Inaguma, Kotaro Oyama, Kotaro Urayama, Kunihiko Takahashi, Kunio Ohta, Makoto Nakazawa, Mami Nakayashiro, Mamoro Ayusawa, Manatomo Toyono, Masaki Nii, Masaru Miura, Mitsuhiro Fujino, Naoshi Kuwabara, Nobuo Momoi, Nobuyuki Tsujii, Noriko Motoki, Osamu Matsuo, Reizo Baba, Ryo Inuzuka, Sachiko Kido, Satoru Iwashima, Satoshi Yasukochi, Seigo Okada, Seiichi Sato, Seki Mitsuru, Shigetoyo Kogaki, Shinsuke Hoshino, Shinya Tsukano, Shuhei Fujita, Sumito Kimura, Susumu Urata, Taichi Kato, Takako Toda, Takamichi Uchiyama, Takahiro Shindo, Takashi Higaki, Tomio Kobayashi, Tomoyasu Ozaki, Yasuhiko Tanaka, Yasuhiro Katsube, Yasunobu Hamabuchi, Yo Kajiyama, Yoko Yoshida, Yosuke Murakami, Yuriko Abe, Yoshimi Hiraumi, Yutaka Fukuda, and Yutaka Odanaka
- Subjects
Heart Defects, Congenital ,Male ,0301 basic medicine ,Tachycardia ,medicine.medical_specialty ,Adolescent ,Cardiomyopathy ,030204 cardiovascular system & hematology ,Ion Channels ,Ventricular Function, Left ,03 medical and health sciences ,High morbidity ,0302 clinical medicine ,Japan ,Internal medicine ,medicine ,Humans ,Child ,Gene ,Genetic Association Studies ,Ion channel ,Proportional Hazards Models ,Isolated Noncompaction of the Ventricular Myocardium ,business.industry ,Infant, Newborn ,Genetic Variation ,Infant ,Arrhythmias, Cardiac ,General Medicine ,medicine.disease ,Survival Analysis ,Phenotype ,030104 developmental biology ,Echocardiography ,Child, Preschool ,Heart failure ,Cardiology ,Left ventricular noncompaction ,Female ,medicine.symptom ,business - Abstract
Background: Left ventricular noncompaction (LVNC) is a hereditary type of cardiomyopathy. Although it is associated with high morbidity and mortality, the related ion channel gene variants in children have not been fully investigated. This study aimed to elucidate the ion channel genetic landscape of LVNC and identify genotype-phenotype correlations in a large Japanese cohort. Methods: We enrolled 206 children with LVNC from 2002 to 2017 in Japan. LVNC was classified as follows: LVNC with congenital heart defects, arrhythmia, dilated phenotype, or normal function. In the enrolled patients, 182 genes associated with cardiomyopathy were screened using next-generation sequencing. Results: We identified 99 pathogenic variants in 40 genes in 87 patients. Of the pathogenic variants, 8.8% were in genes associated with channelopathies, 27% were in sarcomere genes, and 11.5% were in mitochondrial genes. Ion channel gene variants were mostly associated with the arrhythmia classification, whereas sarcomere and mitochondrial gene variants were associated with the dilated phenotype. Echocardiography revealed that the group with ion channel gene variants had almost normal LV ejection fraction and LV diastolic diameter Z scores. Fragmented QRS, old age, and an arrhythmia phenotype were the most significant risk factors for ventricular tachycardia ( P =0.165, 0.0428, and 0.0074, respectively). Moreover, the group with ion channel variants exhibited a greater risk of a higher prevalence of arrhythmias such as ventricular tachycardia, rather than congestive heart failure. Conclusions: This is the first study that focused on genotype-phenotype correlations in a large pediatric LVNC patient cohort with ion channel gene variants that were determined using next-generation sequencing. Ion channel gene variants were strongly correlated with arrhythmia phenotypes. Genetic testing and phenotype specification allow for appropriate medical management of specific LVNC targets.
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- 2020
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44. Comparing risk factors associated with the late detection of critical congenital heart disease at different facility levels
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Yu Konishi, Yukiko Toya, Nao Takashimizu, Genichiro Sotodate, Shigekuni Tsuchiya, Hirofumi Saiki, Kotaro Oyama, and Atsushi Matsumoto
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Heart Defects, Congenital ,Pediatrics ,medicine.medical_specialty ,Referral ,First year of life ,03 medical and health sciences ,0302 clinical medicine ,Neonatal Screening ,Japan ,Risk Factors ,Medicine ,Humans ,Oximetry ,Medical diagnosis ,Critical congenital heart disease ,Oxygen saturation (medicine) ,Retrospective Studies ,030219 obstetrics & reproductive medicine ,medicine.diagnostic_test ,business.industry ,Infant, Newborn ,Obstetrics and Gynecology ,Infant ,Retrospective cohort study ,Pulse oximetry ,Catheter ,030220 oncology & carcinogenesis ,business - Abstract
Aims Critical congenital heart disease (CCHD) requires surgery or catheter intervention within the first year of life; delayed diagnoses result in worsened outcomes. In Japan, there are few reports of delayed CCHD diagnosis. We investigated the diagnoses and factors associated with the late detection of CCHD. Methods This retrospective cohort study evaluated 88 CCHD infants admitted to a level IV facility. We compared the late detection rates across facility levels of neonatal care and CCHD characteristics. Results Critical congenital heart disease was identified prenatally in 46 (52%) infants: early (≤3 days postnatally) in 29 (33%) and late (≥4 days postnatally) in 13 (15%). The oxygen saturation of 27 of 29 infants with early detection and 7 of 13 infants with late detection was measured using pulse oximetry within 3 days postnatally. Factors associated with the late detection of CCHD were lack of clinical recognition of symptoms in five infants, referral to higher-level facilities after discharge in four infants, and definitive diagnosis not confirmed using echocardiography in four infants. The most common factors associated with late detection were referral to higher-level facilities after discharge in level I facilities and definitive diagnosis not confirmed using echocardiography in level II facilities. Conclusion Critical congenital heart disease may require advanced knowledge and echocardiographic techniques for diagnosis. Pulse oximetry and telemedicine should also be incorporated in the diagnostic algorithm. Improvement in these factors might contribute to reducing the late detection of CCHD.
- Published
- 2020
45. A simple method for production of hydrophilic, rigid, and sterilized multi-layer 3D integrated polydimethylsiloxane microfluidic chips
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Kotaro Oyama, Mitsumasa Taguchi, and Tomoko Gowa Oyama
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Materials science ,Biocompatibility ,Polydimethylsiloxane ,Microfluidics ,Biomedical Engineering ,Bioengineering ,Nanotechnology ,General Chemistry ,Biochemistry ,Soft lithography ,Hydrophilization ,chemistry.chemical_compound ,chemistry ,Covalent bond ,Adhesive ,Multi layer - Abstract
Polydimethylsiloxane (PDMS) has many desirable features for microfluidics applications, particularly in diagnostics and pharmaceuticals, but its hydrophobicity and the lack of a practical method for bonding PDMS layers limit its use. Moreover, the flexibility of PDMS causes unwanted deformation during use in some applications. Here, we report a simple method for solving these problems simultaneously using an electron beam (EB) or γ-rays, which are commonly used for sterilizing medical products. Simply by applying EB or γ-ray irradiation to stacked PDMS layers, we can not only bond the interfaces between the layers by forming Si–O–Si covalent bonds but also achieve long-lasting hydrophilization and sterilization of the internal microchannels and chambers, prevent nonspecific adsorption and absorption of hydrophobic small molecules, and enhance the mechanical strength of the material by converting bulk PDMS into a Si–Ox-rich (where x is 3 or 4) structure though crosslinking. Unlike the one-at-a-time plasma process, EBs and γ-rays can penetrate through many stacked layers of PDMS sealed in their final package, enabling batch modification and bonding. The method requires no chemical crosslinkers, adhesive agents, or fillers; hence, it does not undermine the advantages of PDMS such as ease of molding in soft lithography, biocompatibility, and optical transparency. Furthermore, bonding is achieved with high-throughput yield because it occurs after re-adjustable alignment. We demonstrate that this method is applicable in the mass production of 3D integrated PDMS microfluidic chips with some glass-like properties as well as for 3D structures with complex shapes that are difficult to fabricate with plastic or glass.
- Published
- 2020
46. In vivo Cardiac Nano-imaging
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Fuyu Kobirumaki-Shimozawa, Kotaro Oyama, Takako Terui, Togo Shimozawa, and Norio Fukuda
- Subjects
Materials science ,In vivo ,Nano ,Biomedical engineering - Published
- 2019
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47. Hydrostatic Pressure-Regulated Cellular Calcium Responses
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Fukuchi, Minami, Oyama, Kotaro, Mizuno, Hiroaki, Miyagawa, Akihisa, Koumoto, Kazuya, Fukuhara, Gaku, Kotaro, Oyama, Fukuchi, Minami, Oyama, Kotaro, Mizuno, Hiroaki, Miyagawa, Akihisa, Koumoto, Kazuya, Fukuhara, Gaku, and Kotaro, Oyama
- Abstract
Hydrostatic pressure control has attracted much attention and presents a still challenging objective from mechanobiological viewpoints. Herein, we reveal the calcium entry processes in HeLa cells by means of hydrostatic pressure spectroscopy. The steady-state fluorescence spectral data comprehensively elucidated the factors controlling the outcomes of the hydrostatic pressure-stimulated calcium entry behavior. The present work leads to a new perspective on ion regulations in living cells and an attractive alternative to conventional mechanostimuli.
- Published
- 2021
48. Development of carboxymethyl cellulose/gelatin hybrid hydrogels via radiation-induced cross-linking as novel anti-adhesion barriers
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Ahmed E. Swilem, Tomoko Gowa Oyama, Kotaro Oyama, Atsushi Kimura, and Mitsumasa Taguchi
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Polymers and Plastics ,Mechanics of Materials ,Materials Chemistry ,Condensed Matter Physics - Abstract
腹部手術後に起こる周囲臓器との癒着は患者のQOLを著しく低下させる炎症反応であり、手術時に体内に留置する癒着防止剤の開発が望まれている。本研究では、細胞非接着材料のカルボキシメチルセルロース(CMC)と生体適合性・生分解性に優れたゼラチンからなるハイブリッドゲルをガンマ線架橋技術で創出した。架橋剤等を用いずに作製したこのゲルは、母材の生体適合性・生分解性を保っている。成分比を調整した結果、CMC60%・ゼラチン40%の割合で作製したゲルは、線維芽細胞の接着・浸潤を防止しつつ、細胞生存率を有意に高めることが分かった。また、このゲルの生分解速度を調整すると共に、硬さを腹部と同程度となる数10kPaの圧縮弾性率に調整することもできた。移植物と臓器との機械的なマッチングは異物反応を抑制することが分かっており、開発したゲルは、移植後の異物反応を抑制し創傷治癒後に分解される、機能性癒着防止剤として応用が期待される。
- Published
- 2022
49. Fetal intracranial hemorrhage due to maternal subclinical vitamin K deficiency associated with long-term eating disorder
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Kotaro Oyama, Genichiro Sotodate, Mikiya Endo, Yu Konishi, Atsushi Matsumoto, and Yukiko Toya
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Vitamin ,Prothrombin time ,Psychosis ,Fetus ,030219 obstetrics & reproductive medicine ,medicine.diagnostic_test ,business.industry ,Obstetrics and Gynecology ,Physiology ,medicine.disease ,03 medical and health sciences ,chemistry.chemical_compound ,Eating disorders ,0302 clinical medicine ,Intravenous fluid ,chemistry ,030220 oncology & carcinogenesis ,Vitamin K deficiency ,medicine ,cardiovascular diseases ,business ,Subclinical infection - Abstract
Vitamin K deficiency in pregnant women causes intracranial hemorrhage (ICH) in fetuses. Fetal ICH frequently causes life-threatening and persistent neurological damage. However, indicators for preventing fetal ICH are not established. Two pregnant women developed long-term eating disorders caused by psychosis. They were administered intravenous fluid and vitamin supplementation, excluding vitamin K. The intracranial low-hypoechoic area on fetal ultrasound was suggestive of fetal ICH due to vitamin K deficiency. Their neonates showed severe developmental delay. Laboratory analysis revealed a normal prothrombin time, but elevated protein induced by vitamin K absence II. Pregnant women who have eating disorders more than 3 weeks could develop fetal ICH due to maternal subclinical vitamin K deficiency. Illness duration and protein induced by vitamin K absence II of pregnant woman may be indicators for vitamin K administration to prevent fetal intracranial hemorrhage.
- Published
- 2018
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50. Optimization of Fluorescent Labeling for In Vivo Nanoimaging of Sarcomeres in the Mouse Heart
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Kotaro Oyama, Takako Terui, Togo Shimozawa, Fuyu Kobirumaki-Shimozawa, Norio Fukuda, Shin'ichi Ishiwata, and Yasuharu Kushida
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Sarcomeres ,0301 basic medicine ,Contraction (grammar) ,Article Subject ,Heart Ventricles ,Genetic Vectors ,lcsh:Medicine ,030204 cardiovascular system & hematology ,medicine.disease_cause ,Sarcomere ,General Biochemistry, Genetics and Molecular Biology ,Adenoviridae ,Viral vector ,Mice ,03 medical and health sciences ,0302 clinical medicine ,In vivo ,medicine ,Animals ,Nanotechnology ,Myocyte ,Actinin ,Myocytes, Cardiac ,General Immunology and Microbiology ,Chemistry ,lcsh:R ,General Medicine ,Molecular biology ,Titer ,030104 developmental biology ,medicine.anatomical_structure ,Ventricle ,Research Article - Abstract
The present study was conducted to systematically investigate the optimal viral titer as well as the volume of the adenovirus vector (ADV) that expresses α-actinin-AcGFP in the Z-disks of myocytes in the left ventricle (LV) of mice. An injection of 10 μL ADV at viral titers of 2 to 4 × 1011 viral particles per mL (VP/mL) into the LV epicardial surface consistently expressed α-actinin-AcGFP in myocytes in vivo, with the fraction of AcGFP-expressing myocytes at ~10%. Our analysis revealed that SL was ~1.90-2.15 μm upon heart arrest via deep anesthesia. Likewise, we developed a novel fluorescence labeling method of the T-tubular system by treating the LV surface with CellMask Orange (CellMask). We found that the T-tubular distance was ~2.10-2.25 μm, similar to SL, in the healthy heart in vivo. Therefore, the present high-precision visualization method for the Z-disks or the T-tubules is beneficial to unveiling the mechanisms of myocyte contraction in health and disease in vivo.
- Published
- 2018
- Full Text
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