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Reddy CD, Yokota R, Punn R. Tricuspid valve annular tilt for assessment of pre- and post-intervention right ventricular volume in patients undergoing transcatheter pulmonary valve replacement. Cardiol Young 2024; 34:171-177. [PMID: 37309189 DOI: 10.1017/s1047951123001452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
INTRODUCTION Transcatheter pulmonary valve replacement serves as a successful alternative to surgical replacement of a right ventricle to pulmonary artery conduit. Guidelines for recommending transcatheter pulmonary valve replacement depend on MRI right ventricular volumes, which have been correlated to the echocardiographic measure of right ventricular annular tilt. We aim to assess whether right ventricular annular tilt can be a clinically useful alternative tool in the acute and long-term periods after transcatheter pulmonary valve replacement to assess right ventricular health. METHODS We reviewed 70 patients who underwent transcatheter pulmonary valve replacement at a single institution. Echocardiographic measurements were obtained prior to transcatheter pulmonary valve replacement, immediately after transcatheter pulmonary valve replacement, and within 6 months to 1 year after transcatheter pulmonary valve replacement. Right ventricular annular tilt measures the angle of the tricuspid valve plane relative to the mitral valve plane at end-diastole in the apical four-chamber view. Right ventricular fractional area change, right ventricular systolic strain, tissue Doppler velocity, and tricuspid annular plane systolic excursion Z-scores were obtained using published methods. RESULTS Right ventricular annular tilt decreased significantly immediately after transcatheter pulmonary valve replacement (p = 0.0004), and this reduction in right ventricular volume persisted at the mid-term follow-up (p < 0.0001). Fractional area change did not change significantly after transcatheter pulmonary valve replacement while right ventricular global strain improved at mid-term follow-up despite no significant difference immediately after transcatheter pulmonary valve replacement. CONCLUSIONS Right ventricular annular tilt decreases both immediately after transcatheter pulmonary valve replacement and at mid-term follow-up. Right ventricular strain also improved after transcatheter pulmonary valve replacement, corresponding to the improved volume load. Right ventricular annular tilt can be considered as an additional echocardiographic factor to assess right ventricular volume and remodeling after transcatheter pulmonary valve replacement.
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Affiliation(s)
- C D Reddy
- Department of Pediatrics, Division of Pediatric Cardiology, Stanford University, Palo Alto, CA, USA
| | - R Yokota
- Department of Pediatrics, Division of Pediatric Cardiology, Stanford University, Palo Alto, CA, USA
| | - R Punn
- Department of Pediatrics, Division of Pediatric Cardiology, Stanford University, Palo Alto, CA, USA
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Yokota R, Sakamoto SI, Murata T, Hiromoto A, Yamaguchi T, Suzuki K, Kobayashi M, Kure S, Takeno M, Ishii Y. A Case of Contained Rupture of the Common Iliac Artery with Idiopathic Retroperitoneal Fibrosis: Efficacy of Surgical Treatment and Immunosuppressive Therapy at 2-Year Follow-Up. Ann Vasc Dis 2023; 16:95-99. [PMID: 37006861 PMCID: PMC10064296 DOI: 10.3400/avd.cr.22-00120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 01/13/2023] [Indexed: 03/04/2023] Open
Abstract
Rupture of inflammatory aortic aneurysm associated with retroperitoneal fibrosis (RF) is rare. We report a 62-year-old man with an inflammatory abdominal aortic aneurysm (IAAA) complicated with idiopathic RF, resulting in a contained rupture of the common iliac artery. The patient also presented with mild renal insufficiency due to urethral obstruction and left hydronephrosis. Surgical procedures including graft replacement and ureterolysis relieved the symptoms. Postoperative immunosuppressive treatment using corticosteroid and methotrexate successfully maintained clinical remission without signs of recurrence of RF and IAAA at the 2-year follow-up.
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Affiliation(s)
- Ryo Yokota
- Department of Cardiovascular Surgery, Nippon Medical School Musashikosugi Hospital
| | - Shun-Ichiro Sakamoto
- Department of Cardiovascular Surgery, Nippon Medical School Musashikosugi Hospital
| | - Tomohiro Murata
- Department of Cardiovascular Surgery, Nippon Medical School Musashikosugi Hospital
| | - Atsushi Hiromoto
- Department of Cardiovascular Surgery, Nippon Medical School Musashikosugi Hospital
| | - Takako Yamaguchi
- Department of Cardiovascular Surgery, Nippon Medical School Musashikosugi Hospital
| | - Kenji Suzuki
- Department of Cardiovascular Surgery, Nippon Medical School Musashikosugi Hospital
| | - Michiko Kobayashi
- Department of Integrated Diagnostic Pathology, Nippon Medical School Musashi-kosugi Hospital
| | - Shoko Kure
- Department of Integrated Diagnostic Pathology, Nippon Medical School Musashi-kosugi Hospital
| | - Mitsuhiro Takeno
- Department of Allergy and Rheumatology, Nippon Medical School Musashikosugi Hospital
| | - Yosuke Ishii
- Department of Cardiovascular Surgery, Nippon Medical School
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3
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Katayama Y, Yokota R, Akiyama T, Kobayashi TJ. Machine Learning Approaches to TCR Repertoire Analysis. Front Immunol 2022; 13:858057. [PMID: 35911778 PMCID: PMC9334875 DOI: 10.3389/fimmu.2022.858057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 06/07/2022] [Indexed: 11/13/2022] Open
Abstract
Sparked by the development of genome sequencing technology, the quantity and quality of data handled in immunological research have been changing dramatically. Various data and database platforms are now driving the rapid progress of machine learning for immunological data analysis. Of various topics in immunology, T cell receptor repertoire analysis is one of the most important targets of machine learning for assessing the state and abnormalities of immune systems. In this paper, we review recent repertoire analysis methods based on machine learning and deep learning and discuss their prospects.
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Affiliation(s)
- Yotaro Katayama
- Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
- *Correspondence: Yotaro Katayama,
| | - Ryo Yokota
- National Research Institute of Police Science, Kashiwa, Chiba, Japan
| | - Taishin Akiyama
- Laboratory for Immune Homeostasis, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
- Graduate School of Medical Life Science, Yokohama City University, Yokohama, Japan
| | - Tetsuya J. Kobayashi
- Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
- Institute of Industrial Science, The University of Tokyo, Tokyo, Japan
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Kamachi H, Homma S, Kawamura H, Yoshida T, Ohno Y, Ichikawa N, Yokota R, Funakoshi T, Maeda Y, Takahashi N, Amano T, Taketomi A. Intermittent pneumatic compression versus additional prophylaxis with enoxaparin for prevention of venous thromboembolism after laparoscopic surgery for gastric and colorectal malignancies: multicentre randomized clinical trial. BJS Open 2020; 4:804-810. [PMID: 32700415 PMCID: PMC7528532 DOI: 10.1002/bjs5.50323] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 06/09/2020] [Indexed: 11/06/2022] Open
Abstract
Background The role of antithrombotic chemoprophylaxis in prevention of venous thromboembolism (VTE) in laparoscopic surgery for gastric and colorectal malignancies is unknown. This study compared the addition of enoxaparin following intermittent pneumatic compression (IPC) with IPC alone in patients undergoing laparoscopic surgery for gastrointestinal malignancy. Methods In this multicentre RCT, eligible patients were older than 40 years and had a WHO performance status of 0 or 1. Exclusion criteria were prescription of antiplatelet or anticoagulant drugs and history of VTE. Patients were allocated to IPC or to ICP with enoxaparin in a 1 : 1 ratio. Stratification factors included sex, location of cancer, age 61 years and over, and institution. Enoxaparin was administered on days 1–7 after surgery. Primary outcome was VTE, evaluated by multidetector CT on day 7. Results Of 448 patients randomized, 208 in the IPC group and 182 in the IPC with enoxaparin group were evaluated. VTE occurred in ten patients (4·8 per cent) in the IPC group and six (3·3 per cent) in the IPC with enoxaparin group (P = 0·453). Proximal deep vein thrombosis and/or pulmonary embolism occurred in seven patients (3·4 per cent) in the IPC group and one patient (0·5 per cent) in the IPC with enoxaparin group (P = 0·050). All VTE events were asymptomatic and non‐fatal. Bleeding occurred in 11 of 202 patients in the IPC with enoxaparin group, and one patient needed a transfusion. All bleeding events were managed by discontinuation of the drug. Conclusion IPC with enoxaparin after laparoscopic surgery for gastric and colorectal malignancies did not reduce the rate of VTE. Registration number: UMIN000011667 (
https://www.umin.ac.jp/).
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Affiliation(s)
- H Kamachi
- Department of Gastroenterological Surgery I, Graduate School of Medicine, Hokkaido University, Hokkaido, Japan
| | - S Homma
- Department of Gastroenterological Surgery I, Graduate School of Medicine, Hokkaido University, Hokkaido, Japan
| | - H Kawamura
- Department of Gastroenterological Surgery I, Graduate School of Medicine, Hokkaido University, Hokkaido, Japan
| | - T Yoshida
- Department of Gastroenterological Surgery I, Graduate School of Medicine, Hokkaido University, Hokkaido, Japan
| | - Y Ohno
- Department of Gastroenterological Surgery I, Graduate School of Medicine, Hokkaido University, Hokkaido, Japan
| | - N Ichikawa
- Department of Gastroenterological Surgery I, Graduate School of Medicine, Hokkaido University, Hokkaido, Japan
| | - R Yokota
- Department of Surgery, Sunagawa City Medical Centre, Sunagawa, Japan
| | - T Funakoshi
- Department of Surgery, Asahikawa-Kosei General Hospital, Asahikawa, Japan
| | - Y Maeda
- Department of Gastrointestinal Surgery, National Hospital Organization Hokkaido Cancer Centre, Hokkaido
| | | | - T Amano
- Clinical Research and Medical Innovation Centre, Hokkaido University Hospital, Hokkaido, Japan
| | - A Taketomi
- Department of Gastroenterological Surgery I, Graduate School of Medicine, Hokkaido University, Hokkaido, Japan
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5
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Ichikawa N, Homma S, Funakoshi T, Ohshima T, Hirose K, Yamada K, Nakamoto H, Kazui K, Yokota R, Honma T, Maeda Y, Yoshida T, Ishikawa T, Iijima H, Aiyama T, Taketomi A. Impact of technically qualified surgeons on laparoscopic colorectal resection outcomes: results of a propensity score-matching analysis. BJS Open 2020; 4:486-498. [PMID: 32207580 PMCID: PMC7260420 DOI: 10.1002/bjs5.50263] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 12/21/2019] [Indexed: 02/06/2023] Open
Abstract
Background The Endoscopic Surgical Skill Qualification System (ESSQS) was introduced in Japan to improve the quality of laparoscopic surgery. This cohort study investigated the short‐ and long‐term postoperative outcomes of colorectal cancer laparoscopic procedures performed by or with qualified surgeons compared with outcomes for unqualified surgeons. Methods All laparoscopic colorectal resections performed from 2010 to 2013 in 11 Japanese hospitals were reviewed retrospectively. The procedures were categorized as performed by surgeons with or without the ESSQS qualification and patients' clinical, pathological and surgical features were used to match subgroups using propensity scoring. Outcome measures included postoperative and long‐term results. Results Overall, 1428 procedures were analysed; 586 procedures were performed with ESSQS‐qualified surgeons and 842 were done by ESSQS‐unqualified surgeons. Upon matching, two cohorts of 426 patients were selected for comparison of short‐term results. A prevalence of rectal resection (50·3 versus 40·5 per cent; P < 0·001) and shorter duration of surgery (230 versus 238 min; P = 0·045) was reported for the ESSQS group. Intraoperative and postoperative complication and reoperation rates were significantly lower in the ESSQS group than in the non‐ESSQS group (1·2 versus 3·6 per cent, P = 0·014; 4·6 versus 7·5 per cent, P = 0·025; 1·9 versus 3·9 per cent, P = 0·023, respectively). These findings were confirmed after propensity score matching. Cox regression analysis found that non‐attendance of ESSQS‐qualified surgeons (hazard ratio 12·30, 95 per cent c.i. 1·28 to 119·10; P = 0·038) was independently associated with local recurrence in patients with stage II disease. Conclusion Laparoscopic colorectal procedures performed with ESSQS‐qualified surgeons showed improved postoperative results. Further studies are needed to investigate the impact of the qualification on long‐term oncological outcomes.
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Affiliation(s)
- N Ichikawa
- Department of Gastroenterological Surgery I, Graduate School of Medicine, Hokkaido University, Sapporo
| | - S Homma
- Department of Gastroenterological Surgery I, Graduate School of Medicine, Hokkaido University, Sapporo
| | - T Funakoshi
- Department of Surgery, Sapporo-Kosei General Hospital, Sapporo
| | - T Ohshima
- Department of Surgery, Sapporo City General Hospital, Sapporo
| | - K Hirose
- Department of Surgery, Tomakomai City Hospital, Tomakomai
| | - K Yamada
- Department of Surgery, Asahikawa-Kosei General Hospital, Asahikawa
| | - H Nakamoto
- Department of Surgery, KKR Sapporo Medical Centre, Sapporo
| | - K Kazui
- Department of Surgery, Hokkaido Hospital, Japan Community Healthcare Organization, Sapporo
| | - R Yokota
- Department of Surgery, Sunagawa City Medical Centre, Sunagawa
| | - T Honma
- Department of Surgery, Obihiro Kyokai Hospital, Obihiro
| | - Y Maeda
- Department of Gastroenterological Surgery, Hokkaido Cancer Centre, Sapporo
| | - T Yoshida
- Department of Gastroenterological Surgery I, Graduate School of Medicine, Hokkaido University, Sapporo
| | - T Ishikawa
- Department of Surgery, Kushiro Rosai Hospital, Japan Labour Health and Welfare Organization, Kushiro
| | - H Iijima
- Clinical Research and Medical Innovation Centre, Hokkaido University Hospital, Sapporo
| | - T Aiyama
- Department of Gastroenterological Surgery I, Graduate School of Medicine, Hokkaido University, Sapporo
| | - A Taketomi
- Department of Gastroenterological Surgery I, Graduate School of Medicine, Hokkaido University, Sapporo
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Affiliation(s)
- D. S. Shamshirgar
- Department of Mathematics and Swedish e-Science Research Centre, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden
| | - R. Yokota
- Global Scientific Information and Computing Center, Tokyo Institute of Technology, Tokyo, Japan
| | - A.-K. Tornberg
- Department of Mathematics and Swedish e-Science Research Centre, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden
| | - B. Hess
- Department of Applied Physics and Swedish e-Science Research Centre, KTH Royal Institute of Technology, 106 91 Stockholm, Sweden
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7
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Kaneko KB, Tateishi R, Miyao T, Takakura Y, Akiyama N, Yokota R, Akiyama T, Kobayashi TJ. Quantitative analysis reveals reciprocal regulations underlying recovery dynamics of thymocytes and thymic environment in mice. Commun Biol 2019; 2:444. [PMID: 31815199 PMCID: PMC6884561 DOI: 10.1038/s42003-019-0688-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 11/10/2019] [Indexed: 01/17/2023] Open
Abstract
Thymic crosstalk, a set of reciprocal regulations between thymocytes and the thymic environment, is relevant for orchestrating appropriate thymocyte development as well as thymic recovery from various exogenous insults. In this work, interactions shaping thymic crosstalk and the resultant dynamics of thymocytes and thymic epithelial cells are inferred based on quantitative analysis and modeling of the recovery dynamics induced by irradiation. The analysis identifies regulatory interactions consistent with known molecular evidence and reveals their dynamic roles in the recovery process. Moreover, the analysis also predicts, and a subsequent experiment verifies, a previously unrecognized regulation of CD4+CD8+ double positive thymocytes which temporarily increases their proliferation rate upon the decrease in their population size. Our model establishes a pivotal step towards the dynamic understanding of thymic crosstalk as a regulatory network system.
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Affiliation(s)
- Kazumasa B. Kaneko
- Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku Tokyo, 113-8656 Japan
| | - Ryosuke Tateishi
- RIKEN Center for Integrative Medical Sciences, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045 Japan
| | - Takahisa Miyao
- RIKEN Center for Integrative Medical Sciences, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045 Japan
| | - Yuki Takakura
- RIKEN Center for Integrative Medical Sciences, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045 Japan
| | - Nobuko Akiyama
- RIKEN Center for Integrative Medical Sciences, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045 Japan
| | - Ryo Yokota
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku Tokyo, 153-8505 Japan
| | - Taishin Akiyama
- RIKEN Center for Integrative Medical Sciences, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045 Japan
| | - Tetsuya J. Kobayashi
- Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku Tokyo, 113-8656 Japan
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku Tokyo, 153-8505 Japan
- PREST, Japan Science and Technology Agency (JST), 4-1-8 Honcho Kawaguchi, Saitama, 332-0012 Japan
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8
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Yokota R, Kaminaga Y, Kobayashi TJ. Quantification of Inter-Sample Differences in T-Cell Receptor Repertoires Using Sequence-Based Information. Front Immunol 2017; 8:1500. [PMID: 29187849 PMCID: PMC5694755 DOI: 10.3389/fimmu.2017.01500] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Accepted: 10/24/2017] [Indexed: 11/13/2022] Open
Abstract
Inter-sample comparisons of T-cell receptor (TCR) repertoires are crucial for gaining a better understanding of the immunological states determined by different collections of T cells from different donor sites, cell types, and genetic and pathological backgrounds. For quantitative comparison, most previous studies utilized conventional methods in ecology, which focus on TCR sequences that overlap between pairwise samples. Some recent studies attempted another approach that is categorized into Poisson abundance models using the abundance distribution of observed TCR sequences. However, these methods ignore the details of the measured sequences and are consequently unable to identify sub-repertoires that might have important contributions to the observed inter-sample differences. Moreover, the sparsity of sequence data due to the huge diversity of repertoires hampers the performance of these methods, especially when few overlapping sequences exist. In this paper, we propose a new approach for REpertoire COmparison in Low Dimensions (RECOLD) based on TCR sequence information, which can estimate the low-dimensional structure by embedding the pairwise sequence dissimilarities in high-dimensional sequence space. The inter-sample differences between repertoires are then quantified by information-theoretic measures among the distributions of data estimated in the embedded space. Using datasets of mouse and human TCR repertoires, we demonstrate that RECOLD can accurately identify the inter-sample hierarchical structures, which have a good correspondence with our intuitive understanding about sample conditions. Moreover, for the dataset of transgenic mice that have strong restrictions on the diversity of their repertoires, our estimated inter-sample structure was consistent with the structure estimated by previous methods based on abundance or overlapping sequence information. For the dataset of human healthy donors and Sézary syndrome patients, our method also showed robust estimation performance even under the condition of high sparsity in TCR sequences, while previous studies failed to estimate the structure. In addition, we identified the sequences that contribute to the pairwise-sample differences between the repertoires with the different genetic backgrounds of mice. Such identification of the sequences contributing to variation in immune cell repertoires may provide substantial insight for the development of new immunotherapies and vaccines.
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Affiliation(s)
- Ryo Yokota
- Institute of Industrial Science, The University of Tokyo, Tokyo, Japan
| | - Yuki Kaminaga
- Department of Electrical Engineering and Information Systems, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Tetsuya J Kobayashi
- Institute of Industrial Science, The University of Tokyo, Tokyo, Japan.,Department of Electrical Engineering and Information Systems, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan.,PRESTO, Japan Science and Technology Agency (JST), Saitama, Japan
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9
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Yokota R, Enatsu N, Furuhashi K, Kishi K, Tsuji Y, Otsuki J, Matsumoto Y, Kokeguchi S, Shiotani M. Clinical value of the newly developed nomogram predicting the fertilization outcome in assisted reproductive technology (ART). Fertil Steril 2017. [DOI: 10.1016/j.fertnstert.2017.07.451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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10
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Hirata Y, Amigó JM, Matsuzaka Y, Yokota R, Mushiake H, Aihara K. Detecting Causality by Combined Use of Multiple Methods: Climate and Brain Examples. PLoS One 2016; 11:e0158572. [PMID: 27380515 PMCID: PMC4933387 DOI: 10.1371/journal.pone.0158572] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 06/18/2016] [Indexed: 11/21/2022] Open
Abstract
Identifying causal relations from time series is the first step to understanding the behavior of complex systems. Although many methods have been proposed, few papers have applied multiple methods together to detect causal relations based on time series generated from coupled nonlinear systems with some unobserved parts. Here we propose the combined use of three methods and a majority vote to infer causality under such circumstances. Two of these methods are proposed here for the first time, and all of the three methods can be applied even if the underlying dynamics is nonlinear and there are hidden common causes. We test our methods with coupled logistic maps, coupled Rössler models, and coupled Lorenz models. In addition, we show from ice core data how the causal relations among the temperature, the CH4 level, and the CO2 level in the atmosphere changed in the last 800,000 years, a conclusion also supported by irregularly sampled data analysis. Moreover, these methods show how three regions of the brain interact with each other during the visually cued, two-choice arm reaching task. Especially, we demonstrate that this is due to bottom up influences at the beginning of the task, while there exist mutual influences between the posterior medial prefrontal cortex and the presupplementary motor area. Based on our results, we conclude that identifying causality with an appropriate ensemble of multiple methods ensures the validity of the obtained results more firmly.
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Affiliation(s)
- Yoshito Hirata
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153–8505, Japan
| | - José M. Amigó
- Centro de Investigación Operativa, Universidad Miguel Hernández, Avda. de la Universidad s/n, 03202, Elche, Spain
| | - Yoshiya Matsuzaka
- Department of Physiology, Tohoku University School of Medicine, 2–1 Seiryo-machi Aoba-ku, Sendai, Miyagi, 980–8575, Japan
| | - Ryo Yokota
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153–8505, Japan
| | - Hajime Mushiake
- Department of Physiology, Tohoku University School of Medicine, 2–1 Seiryo-machi Aoba-ku, Sendai, Miyagi, 980–8575, Japan
| | - Kazuyuki Aihara
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153–8505, Japan
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11
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Kajita MK, Yokota R, Aihara K, Kobayashi TJ. Experimental and theoretical bases for mechanisms of antigen discrimination by T cells. Biophysics (Nagoya-shi) 2015; 11:85-92. [PMID: 27493520 PMCID: PMC4736787 DOI: 10.2142/biophysics.11.85] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 02/01/2015] [Indexed: 12/01/2022] Open
Abstract
Interaction only within specific molecules is a requisite for accurate operations of a biochemical reaction in a cell where bulk of background molecules exist. While structural specificity is a well-established mechanism for specific interaction, biophysical and biochemical experiments indicate that the mechanism is not sufficient for accounting for the antigen discrimination by T cells. In addition, the antigen discrimination by T cells also accompanies three intriguing properties other than the specificity: sensitivity, speed, and concentration compensation. In this work, we review experimental and theoretical works on the antigen discrimination by focusing on these four properties and show future directions towards understanding of the fundamental principle for molecular discrimination.
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Affiliation(s)
- Masashi K Kajita
- Department of Mathematical Informatics, Graduate School of Information Science and Technology, The University of Tokyo, 4-6-1 Komaba Meguro-ku, Tokyo 153-8505, Japan
| | - Ryo Yokota
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba Meguro-ku, Tokyo 153-8505, Japan
| | - Kazuyuki Aihara
- Department of Mathematical Informatics, Graduate School of Information Science and Technology, The University of Tokyo, 4-6-1 Komaba Meguro-ku, Tokyo 153-8505, Japan; Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba Meguro-ku, Tokyo 153-8505, Japan
| | - Tetsuya J Kobayashi
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba Meguro-ku, Tokyo 153-8505, Japan
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12
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Lee SH, Kyung H, Yokota R, Goto T, Oe T. Hydroxyl Radical-Mediated Novel Modification of Peptides: N-Terminal Cyclization through the Formation of α-Ketoamide. Chem Res Toxicol 2014; 28:59-70. [DOI: 10.1021/tx500332y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Seon Hwa Lee
- Department of Bio-analytical
Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Hyunsook Kyung
- Department of Bio-analytical
Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Ryo Yokota
- Department of Bio-analytical
Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Takaaki Goto
- Department of Bio-analytical
Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Tomoyuki Oe
- Department of Bio-analytical
Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
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13
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Yokota R, Aihara K, Kanzaki R, Takahashi H. Learning-stage-dependent plasticity of temporal coherence in the auditory cortex of rats. Brain Topogr 2014; 28:401-10. [PMID: 24615394 DOI: 10.1007/s10548-014-0359-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 02/20/2014] [Indexed: 10/25/2022]
Abstract
Temporal coherence among neural populations may contribute importantly to signal encoding, specifically by providing an optimal tradeoff between encoding reliability and efficiency. Here, we considered the possibility that learning modulates the temporal coherence among neural populations in association with well-characterized map plasticity. We previously demonstrated that, in appetitive operant conditioning tasks, the tone-responsive area globally expanded during the early stage of learning, but shrank during the late stage. The present study further showed that phase locking of the first spike to band-specific oscillations of local field potentials (LFPs) significantly increased during the early stage of learning but decreased during the late stage, suggesting that neurons in A1 were more synchronously activated during early learning, whereas they were more asynchronously activated once learning was completed. Furthermore, LFP amplitudes increased during early learning but decreased during later learning. These results suggest that, compared to naïve encoding, early-stage encoding is more reliable but energy-consumptive, whereas late-stage encoding is more energetically efficient. Such a learning-stage-dependent encoding strategy may underlie learning-induced, non-monotonic map plasticity. Accumulating evidence indicates that the cholinergic system is likely to be a shared neural substrate of the processes for perceptual learning and attention, both of which modulate neural encoding in an adaptive manner. Thus, a better understanding of the links between map plasticity and modulation of temporal coherence will likely lead to a more integrated view of learning and attention.
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Affiliation(s)
- Ryo Yokota
- Research Center for Advanced Science and Technology, The University of Tokyo, Komaba 4-6-1, Meguro-ku, Tokyo, 153-8904, Japan
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Abstract
We have previously reported that N-terminal α-ketoamide peptides can be formed through 4-oxo-2(E)-nonenal (ONE)-derived oxidative decarboxylation of aspartic acid (Asp), which converts angiotensin (Ang) II (DRVYIHPF) to pyruvamide-Ang II (Ang P, CH3COCONH-RVYIHPF). The pyruvamide group significantly inhibits Ang P binding to the Ang II type 1 receptor, which mediates the major biological effects of Ang II. In the present study, we found that ONE can also introduce an α-ketoamide moiety at the N-terminus of peptides containing N-terminal residues other than Asp. Subsequent investigation of alternative biosynthetic pathways for N-terminal α-ketoamide peptides revealed that hydroxyl radical-mediated formation is a much more efficient route. The proposed mechanism involves initial abstraction of the N-terminal α-hydrogen and hydrolysis of the ketimine intermediate. The resulting N-terminal α-ketoamide is then converted to the D- and L-amino acids by nonenzymatic transamination in the presence of pyridoxamine (PM). The formation of the epimeric N-terminus depended on the incubation time and the concentration of PM, and increased further upon the addition of Cu(II) ions. A conversion of approximately 60% after three days of incubation was observed for Ang P. We propose that the reaction intermediate contains a prochiral α-carbon and is stabilized by the chelate effect of Cu(II) ions. The ONE- and hydroxyl radical-derived formation of N-terminal α-ketoamide and its transamination in the presence of PM were also observed in amyloid β 1-11 (DAEFRHDSGYE), where the N-terminal Asp was converted to epimeric alanine. This suggests that these N-terminal modifications could occur in vivo and modulate the biological functions of peptides and proteins.
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Affiliation(s)
- Seon Hwa Lee
- Department of Bio-analytical Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University , Aobayama, Aoba-ku, Sendai 980-8578, Japan
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Abstract
The mechanisms by which functional maps and map plasticity contribute to cortical computation remain controversial. Recent studies have revisited the theory of neural Darwinism to interpret the learning-induced map plasticity and neuronal heterogeneity observed in the cortex. Here, we hypothesize that the Darwinian principle provides a substrate to explain the relationship between neuron heterogeneity and cortical functional maps. We demonstrate in the rat auditory cortex that the degree of response variance is closely correlated with the size of its representational area. Further, we show that the response variance within a given population is altered through training. These results suggest that larger representational areas may help to accommodate heterogeneous populations of neurons. Thus, functional maps and map plasticity are likely to play essential roles in Darwinian computation, serving as effective, but not absolutely necessary, structures to generate diverse response properties within a neural population.
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Affiliation(s)
- Hirokazu Takahashi
- Graduate School of Information Science and Technology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
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Hirasaki S, Murakami K, Mizushima T, Ohmori K, Fujita S, Hanayama Y, Kanamori T, Yokota R, Ebara H, Kusano N, Kudo C, Yamaguchi T, Akagi T, Koide N. Successful treatment of sepsis caused by Staphylococcus lugdunensis in an adult with 22q11.2 deletion syndrome. Intern Med 2012; 51:377-80. [PMID: 22333372 DOI: 10.2169/internalmedicine.51.6257] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A 27-year-old woman visited our hospital because of high fever. She had been diagnosed as 22q11.2 deletion syndrome (22q11.2DS) due to her cardiac history (tetralogy of Fallot), thymic hypoplasia and 22q11.2 deletion. She had a normal CD4/CD8 ratio, a slightly decreased lymphocyte count and normal serum immunoglobulin levels. Blood cultures were positive for Staphylococcus lugdunensis (S. lugdunensis). Infection route of S. lugdunensis in this case was unclear. The patient was successfully treated with several intravenous antibiotics. Infection should be considered when managing patients with 22q.11.2DS. regardless of whether their immune system is impaired.
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Affiliation(s)
- Shoji Hirasaki
- Department of General Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Japan.
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Takahashi H, Yokota R, Funamizu A, Kose H, Kanzaki R. Learning-stage-dependent, field-specific, map plasticity in the rat auditory cortex during appetitive operant conditioning. Neuroscience 2011; 199:243-58. [PMID: 21985937 DOI: 10.1016/j.neuroscience.2011.09.046] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 09/21/2011] [Accepted: 09/21/2011] [Indexed: 01/28/2023]
Abstract
Cortical reorganizations during acquisition of motor skills and experience-dependent recovery after deafferentation consist of several distinct phases, in which expansion of receptive fields is followed by the shrinkage and use-dependent refinement. In perceptual learning, however, such non-monotonic, stage-dependent plasticity remains elusive in the sensory cortex. In the present study, microelectrode mapping characterized plasticity in the rat auditory cortex, including primary, anterior, and ventral/suprarhinal auditory fields (A1, AAF, and VAF/SRAF), at the early and late stages of appetitive operant conditioning. We first demonstrate that most plasticity at the early stage was tentative, and that long-lasting plasticity after extended training was able to be categorized into either early- or late-stage-dominant plasticity. Second, training-induced plasticity occurred both locally and globally with a specific temporal order. Conditioned-stimulus (CS) frequency used in the task tended to be locally over-represented in AAF at the early stage and in VAF/SRAF at the late stage. The behavioral relevance of neural responses suggests that the local plasticity also occurred in A1 at the early stage. In parallel, the tone-responsive area globally shrank at the late stage independently of CS frequency, and this shrinkage was also correlated with the behavioral improvements. Thus, the stage-dependent plasticity may commonly underlie cortical reorganization in the perceptual learning, yet the interactions of local and global plasticity have led to more complicated reorganization than previously thought. Field-specific plasticity has important implications for how each field subserves in the learning; for example, consistent with recent notions, A1 should construct filters to better identify auditory objects at the early stage, while VAF/SRAF contribute to hierarchical computation and storage at the late stage.
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Affiliation(s)
- H Takahashi
- Research Center for Advanced Science and Technology, The University of Tokyo, Komaba 4-6-1, Meguro-ku, Tokyo 153-8904, Japan.
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Yokota R, Iser B, Sardinha L, Moura L, Claro R, Malta D. P2-337 Short term trends of obesity using data of the telephone-based surveillance system of risk and protective factors for chronic diseases (VIGITEL), Brazil, 2006 to 2009. Br J Soc Med 2011. [DOI: 10.1136/jech.2011.142976k.69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Yokota R, Iser B, Sardinha L, Moura L, Claro R, Malta D. P2-336 Factors associated with class III obesity among adults, national telephone survey (Vigitel) Brazil, 2009. Br J Soc Med 2011. [DOI: 10.1136/jech.2011.142976k.68] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Souza L, Reis P, Iser B, Yokota R, Almeida W, Bernal R, Malta D, Oliveira W. SP3-92 Influenza like illness monitoring by telephone survey in Brazil, Vigitel, 2010. Br J Soc Med 2011. [DOI: 10.1136/jech.2011.142976o.92] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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21
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Shinomori K, Yokota R, Nakauchi S. Color naming and color categorization by dichromats. J Vis 2010. [DOI: 10.1167/7.15.106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Smukler S, Jackson L, Murphree L, Yokota R, Koike S, Smith R. Transition to large-scale organic vegetable production in the Salinas Valley, California. Agriculture, Ecosystems & Environment 2008; 126:168-188. [PMID: 0 DOI: 10.1016/j.agee.2008.01.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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Yokota R, Takahashi H, Funamizu A, Uchihara M, Suzurikawa J, Kanzaki R. Auditory cortical plasticity induced by intracortical microstimulation under pharmacological blockage of inhibitory synapses. Conf Proc IEEE Eng Med Biol Soc 2007; 2006:4929-32. [PMID: 17946661 DOI: 10.1109/iembs.2006.260281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Electrical stimulation that can reorganize our neural system has a potential for promising neurorehabilitation. We previously demonstrated that temporally controlled intracortical microstimulation (ICMS) could induce the spike time-dependant plasticity and modify tuning properties of cortical neurons as desired. A 'pairing' ICMS following tone-induced excitatory post-synaptic potentials (EPSPs) produced potentiation in response to the paired tones, while an 'anti-pairing' ICMS preceding the tone-induced EPSPs resulted in depression. However, the conventional ICMS affected both excitatory and inhibitory synapses, and thereby could not quantify net excitatory synaptic effects. In the present work, we evaluated the ICMS effects under a pharmacological blockage of inhibitory inputs. The pharmacological blockage enhanced the ICMS effects, suggesting that inhibitory inputs determine a plastic degree of the neural system. Alternatively, the conventional ICMS had an inadequate timing to control excitatory synaptic inputs, because inhibitory synapse determined the latency of total neural inputs.
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Affiliation(s)
- R Yokota
- Graduate Sch. of Inf. Sci. & Technol., Tokyo Univ., Meguro-ku, Tokyo, Japan.
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Nakai I, Kondoh H, Amemiya K, Nagasaka M, Shimada T, Yokota R, Nambu A, Ohta T. Mechanism of the CO oxidation reaction on O-precovered Pt(111) surfaces studied with near-edge x-ray absorption fine structure spectroscopy. J Chem Phys 2005; 122:134709. [PMID: 15847491 DOI: 10.1063/1.1869415] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The mechanism of CO oxidation reaction on oxygen-precovered Pt(111) surfaces has been studied by using time-resolved near-edge x-ray absorption fine structure spectroscopy. The whole reaction process is composed of two distinct paths: (1) a reaction of isolated oxygen atoms with adsorbed CO, and (2) a reaction of island-periphery oxygen atoms after the CO saturation. CO coadsorption plays a role to induce the dynamic change in spatial distribution of O atoms, which switches over the two reaction paths. These mechanisms were confirmed by kinetic Monte Carlo simulations. The effect of coadsorbed water in the reaction mechanism was also examined.
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Affiliation(s)
- I Nakai
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Jackson L, Ramirez I, Yokota R, Fennimore S, Koike S, Henderson D, Chaney W, Calderón F, Klonsky K. On-farm assessment of organic matter and tillage management on vegetable yield, soil, weeds, pests, and economics in California. Agriculture, Ecosystems & Environment 2004; 103:443-463. [PMID: 0 DOI: 10.1016/j.agee.2003.11.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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Hergenrother P, Watson K, Smith J, Connell J, Yokota R. Copolyimides from 2,3,3′,4′-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride with 4,4′-oxydianiline. POLYMER 2004. [DOI: 10.1016/j.polymer.2004.06.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Yamasaki K, Tanaka M, Yokota R, Fujiwara H, Sasayama S. Dilazep dihydrochloride prolongs the infarct size-limiting effect of ischemic preconditioning in rabbits. Heart Vessels 2001; 15:227-32. [PMID: 11560359 DOI: 10.1007/s003800070012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Recent studies have indicated the key role of adenosine receptor activation as a trigger for ischemic preconditioning (PC). Hence, the augmentation of endogenous adenosine may potentiate the cardioprotective effects of PC. In this study. we aimed to test the hypothesis that dilazep dihydrochloride, an adenosine transport inhibitor, potentiates the PC effect. Protocol 1: Infarcts were produced in open-chest anesthetized rabbits by 30-min occlusion of a coronary artery and 2 days' reperfusion. PC was elicited by a preceding 5-min occlusion and either 5, 40, or 120 min of reperfusion. PC with the 5-min reperfusion markedly limited the infarct size after the 30-min ischemia (infarct size to area at risk (IS): 10%+/-3% vs 41%+/-3%, P < 0.05). PC was not protective when the reperfusion periods were 40 or 120 min (IS: 47%+/-5% and 44%+/-3%. P = not significant (NS) vs control, respectively). However, concomitant treatment with dilazep (0.2mg/kg) preserved the PC effect in the 40-min reperfusion group (18%+/-5%, P < 0.05 vs control) but not in the 120-min reperfusion group (43%+/-4%, P = NS vs control). Protocol 2: Infarct was produced in a similar rabbit model by either a 45- or 50-min occlusion of a coronary artery and 2 days of reperfusion. PC was elicited by a preceding 5-min occlusion and a 5-min reperfusion. PC was protective in the 45-min occlusion group (30%+/-7% vs 67%+/-3%, P < 0.05) but not in the 50-min occlusion group (74%+/-4% vs 79%+/-5%, P = NS). Treatment with dilazep (0.2mg/kg) failed to retrieve protection in this preconditioned group (77%+/-6%, P = NS vs 50-min occlusion group without PC). Thus, dilazep prolonged the infarct size-limiting effect of PC, but failed to retrieve protection in the group with a longer sustained ischemia.
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Affiliation(s)
- K Yamasaki
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Japan
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Gao Y, Yokota R, Tang S, Ashton AW, Ware JA. Reversal of angiogenesis in vitro, induction of apoptosis, and inhibition of AKT phosphorylation in endothelial cells by thromboxane A(2). Circ Res 2000; 87:739-45. [PMID: 11055976 DOI: 10.1161/01.res.87.9.739] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Thromboxane A(2) (TxA(2)) causes platelet aggregation, vasoconstriction, and inhibition of endothelial cell (EC) migration and prevents vascular tube formation via its specific receptors (TP), of which there are two isoforms (TPalpha and TPbeta), both expressed in human ECs. In this study, we demonstrate that the TxA(2) mimetic IBOP increases apoptosis of human ECs and inhibits the phosphorylation of Akt kinase, an intracellular mediator required for cell survival. Treatment with IBOP destroyed EC networks formed on a basement membrane matrix in vitro. To distinguish the role of the TP isoforms, each isoform was expressed in TP-null ECs to create TPalpha and TPbeta ECs. IBOP induced apoptosis and inhibited phosphorylation of Akt kinase in both TPalpha and TPbeta. IBOP increased cAMP levels in TPalpha but not in TPbeta. Apoptosis induced by IBOP in TPalpha was not affected by either the adenylyl cyclase activator forskolin or the protein kinase A inhibitor 14-22 amide or H-89, whereas that in TPbeta was suppressed by forskolin and enhanced by the protein kinase A inhibitor 14-22 amide or H-89, suggesting that the TP isoforms differ in their signal pathways in mediating apoptosis. In conclusion, apoptosis may be the mechanism by which TxA(2)-mediated destruction of vascular structures in ECs occurs; although both TP isoforms induce apoptosis, possibly via inhibiting Akt phosphorylation, the signaling differs in each isoform, in that activation of the adenylyl cyclase pathway prevents apoptosis caused by TPbeta, but not by TPalpha, stimulation.
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Affiliation(s)
- Y Gao
- Departments of Medicine (Cardiovascular Division), Albert Einstein College of Medicine of Yeshiva University, Bronx, NY, USA
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Yokota R, Fukai M, Shimamura T, Suzuki T, Watanabe Y, Nagashima K, Kishida A, Furukawa H, Hayashi T, Todo S. A novel hydroxyl radical scavenger, nicaraven, protects the liver from warm ischemia and reperfusion injury. Surgery 2000; 127:661-9. [PMID: 10840362 DOI: 10.1067/msy.2000.105864] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND Reactive oxygen species have been considered to be involved in liver injury at the procurement, preservation, and transplantation from donors without beating hearts. A novel hydroxyl radical scavenger, nicaraven with hydrophilic and lipophilic properties, infiltrates both intracellular and extracellular spaces where it effectively scavenges reactive oxygen species. Protection by nicaraven against ischemia and reperfusion damage of the brain, heart, and kidneys has been shown. The effect of this agent on the liver remains unclear. METHODS Two-hour total hepatic vascular exclusion was used. Eighteen beagle dogs were randomly assigned to 2 groups: 12 animals were not treated (group I) and 6 were treated with nicaraven (group II). Nicaraven was administered intravenously (2mg/kg/min) for 60 minutes before ischemia and for 3 hours, starting 30 minutes before reperfusion. RESULTS Two-week survival rates were 25% in group I and 100% in group II (P <.01). Nicaraven inhibited lipid peroxidation in the liver, improved hepatic and systemic hemodynamics and energy metabolism, and suppressed liver enzyme release, endothelin-1 elevation in hepatic venous blood, histologic damage, and neutrophil infiltration into the liver. CONCLUSIONS Nicaraven exerted hepatic protection against warm ischemia and reperfusion injury. This may indicate nicaraven as a potential candidate to attenuate liver injury from warm ischemia and preservation in transplantation from donors without beating hearts.
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Affiliation(s)
- R Yokota
- First Department of Surgery, Hokkaido University School of Medicine, Sapporo, Japan
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Araki M, Tanaka M, Hasegawa K, Yokota R, Maeda T, Ishikawa M, Yabuuchi Y, Sasayama S. Nitric oxide inhibition improved myocardial metabolism independent of tissue perfusion during ischemia but not during reperfusion. J Mol Cell Cardiol 2000; 32:375-84. [PMID: 10731437 DOI: 10.1006/jmcc.1999.1082] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nitric oxide (NO) is one of the important regulators of cardiac metabolism and function as well as of tissue perfusion. Myocardial NO formation is increased during ischemia and reperfusion. We investigated the roles of endogenous NO in myocardial metabolism during ischemia and reperfusion independent of tissue perfusion changes. In an open-chest pig model, a bolus infusion of 20 mg/kg of N(G)-nitro l -arginine methyl ester (l -NAME), a NO synthase inhibitor, did not alter the regional myocardial perfusion compared with a control saline injection, as measured by colored microsphares. Using(31)P-nuclear magnetic resonance spectroscopy, we showed that the tissue levels of pH and adenosine triphosphate (ATP) but not those of creatine phosphate were significantly preserved in the l -NAME group compared with the placebo group during the subsequent 15-min regional ischemia. Thus, l -NAME reduced myocardial ATP utilization during ischemia, and the mechanism underlying these effects is independent of tissue perfusion changes. However, l -NAME did not accelerate the recovery of ATP levels following reperfusion, suggesting distinct roles of endogenous NO during reperfusion.
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Affiliation(s)
- M Araki
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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Ashton AW, Yokota R, John G, Zhao S, Suadicani SO, Spray DC, Ware JA. Inhibition of endothelial cell migration, intercellular communication, and vascular tube formation by thromboxane A(2). J Biol Chem 1999; 274:35562-70. [PMID: 10585431 DOI: 10.1074/jbc.274.50.35562] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The eicosanoid thromboxane A(2) (TXA(2)) is released by activated platelets, monocytes, and the vessel wall and interacts with high affinity receptors expressed in several tissues including endothelium. Whether TXA(2) might alter endothelial migration and tube formation, two determinants of angiogenesis, is unknown. Thus, we investigated the effect of the TXA(2) mimetic [1S-(1alpha, 2beta(5Z),3alpha(1E,3R), 4alpha]-7-[3-(3-hydroxy-4-(4'-iodophenoxy)-1-butenyl)-7-o xab icyclo- [2.2.1]heptan-2-yl]-5'-heptenoic acid (IBOP) on human endothelial cell (HEC) migration and angiogenesis in vitro. IBOP stimulation inhibited HEC migration by 50% and in vitro capillary formation by 75%. These effects of IBOP were time- and concentration-dependent with an IC(50) of 25 nM. IBOP did not affect integrin expression or cytoskeletal morphology of HEC. Since gap junction-mediated intercellular communication increases in migrating HEC, we determined whether IBOP might inhibit coupling or connexin expression in HEC. IBOP reduced the passage of microinjected dyes between HEC by 50%, and the effects of IBOP on migration and tube formation were mimicked by the gap junction inhibitor 18beta-glycyrrhetinic acid (1 microM) with a similar time course and efficacy. IBOP (24 h) did not affect the expression or phosphorylation of connexin 43 in whole HEC lysates. Immunohistologic examination of HEC suggested that IBOP may impair functional coupling by altering the cellular distribution of gap junctions, leading to increased connexin 43 internalization. Thus, this finding that TXA(2) mimetics can prevent HEC migration and tube formation, possibly by impairing intercellular communication, suggests that antagonizing TXA(2) signaling might enhance vascularization of ischemic tissue.
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Affiliation(s)
- A W Ashton
- Department of Medicine (Cardiology), the Albert Einstein College of Medicine of Yeshiva University, Bronx, New York 10461, USA.
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Abstract
BACKGROUND Although protein kinase C (PKC) has been implicated in ischemic cell death, the role of individual PKC isoenzymes in the response of endothelial cells (ECs) to hypoxia is unknown. METHODS AND RESULTS To test the effect of hypoxia on the activity of individual PKC isoenzymes, human ECs were exposed to 95% N(2) with 5% CO(2) for 24 hours. This severe hypoxia reduced PKCdelta specific activity in both human umbilical vein ECs (HUVECs) and a HUVEC-derived EC line (ECVs) significantly (80.5+/-5.7% and 55.5+/-8. 6% of normoxia controls, respectively); the activities of PKCalpha and PKCepsilon were unchanged. The protein levels of PKCalpha, PKCdelta, and PKCepsilon were unchanged by hypoxia. To determine whether PKCdelta downregulation by hypoxia was linked to EC function, ECVs in which PKCdelta was stably overexpressed (PKCdelta-ECs) were exposed to hypoxia. A significant increase in cell death was observed in PKCdelta-ECs compared with controls (5.8+/-0.6% versus 2. 3+/-0.4% at 24 hours, 13.2+/-1.2% versus 4.1+/-0.4% at 48 hours, P<0. 05) during hypoxia. Neither the DNA laddering assay nor TUNEL staining revealed an increase in apoptosis of PKCdelta-ECs exposed to hypoxia, suggesting a hypoxia-induced increase in nonapoptotic cell death of PKCdelta-ECs. Inhibition of NO synthase with N(G)-monomethyl-L-arginine (L-NMMA) affected neither the decline in PKCdelta activity nor the EC death induced by hypoxia. CONCLUSIONS PKCdelta activity is decreased by hypoxia by a mechanism that does not involve NO synthase; this downregulation appears to enhance EC survival during hypoxia by decreasing nonapoptotic cell death.
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Affiliation(s)
- Y Shizukuda
- Cardiovascular Division, Department of Medicine, and the Department of Molecular Pharmacology, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, USA
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Omura T, Suzuki T, Shimamura T, Jin MB, Yokota R, Fukai M, Iida J, Taniguchi M, Magata S, Horiuchi H, Yamashita K, Nomura M, Kishida A, Matsushita M, Furukawa H, Todo S. A short-course therapy with FTY720 prolongs allograft survival after canine kidney transplantation. Transplant Proc 1999; 31:2783-4. [PMID: 10578289 DOI: 10.1016/s0041-1345(99)00565-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- T Omura
- First Department of Surgery, Hokkaido University School of Medicine, Sapporo, Japan
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Shizukuda Y, Tang S, Yokota R, Ware JA. Vascular endothelial growth factor-induced endothelial cell migration and proliferation depend on a nitric oxide-mediated decrease in protein kinase Cdelta activity. Circ Res 1999; 85:247-56. [PMID: 10436167 DOI: 10.1161/01.res.85.3.247] [Citation(s) in RCA: 134] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Vascular endothelial growth factor (VEGF) promotes angiogenesis and endothelial cell (EC) migration and proliferation by affecting intracellular mediators, only some of which are known, distal to its receptors. Protein kinase C (PKC) participates in the function of VEGF, but the role of individual PKC isoenzymes is unknown. In this study, we tested the importance of the activity of specific PKC isoenzymes in human EC migration and proliferation in response to VEGF. PKCdelta specific activity was depressed by the addition of VEGF (by 41+/-8% [P<0.05] at 24 hours) in human umbilical vein ECs (HUVECs) and in a HUVEC-derived EC line, ECV, without changing the total amount of either protein or mRNA encoding PKCdelta. Neither basic fibroblast growth factor (FGF-2) nor serum altered PKCdelta specific activity. The VEGF-induced decrease of PKCdelta activity, which began at 8 hours after stimulation, was strongly blocked by pretreatment with the nitric oxide (NO) synthase inhibitor N(G)-monomethyl-L-arginine in HUVECs; NO release peaked within 2 hours after stimulation. An exogenous NO donor, sodium nitroprusside, also decreased PKCdelta activity. The inhibition by N(G)-monomethyl-L-arginine of VEGF-induced HUVEC migration and proliferation, but not that induced by FGF-2 or serum, suggested that the decrease in PKCdelta via NO pathway is required for VEGF-induced EC migration and proliferation. Overexpression of PKCdelta in ECV cells specifically prevented EC response to VEGF but not to FGF-2 or serum. Thus, we conclude that suppression of PKCdelta activity via a NO synthase mechanism is required for VEGF-induced EC migration and proliferation, but not for that induced by FGF-2 or serum.
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Affiliation(s)
- Y Shizukuda
- Cardiovascular Division, Department of Medicine, Department of Molecular Pharmacology, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, USA
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Horiuchi H, Suzuki T, Taniguchi M, Jin MB, Shimamura T, Fukai M, Yokota R, Iida J, Magata S, Ogata K, Ishikawa H, Kishida A, Furukawa H, Todo S. PROTECTIVE EFFECT OF PROTEASE INHIBITOR, NAFAMOSTAT MESILATE(FUT-175), ON ISCHEMIA REPERFUSION INJURY IN CANINE LIVER. Transplantation 1999. [DOI: 10.1097/00007890-199904150-00328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Iida J, Shimamura T, Suzuki T, Jin MB, Taniguchi M, Fukai M, Yokota R, Horiuchi H, Magata S, Kishida A, Furukawa H, Todo S. Inhibition of thromboxane A2 synthesis by OKY-046 attenuates ischemia and reperfusion injury of the liver. Transplant Proc 1999; 31:1061-2. [PMID: 10083474 DOI: 10.1016/s0041-1345(98)01904-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- J Iida
- First Department of Surgery, Hokkaido University, Sapporo, Japan
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Suzuki T, Shimamura T, Jin MB, Yokota R, Fukai M, Iida J, Taniguchi M, Magata S, Horiuchi H, Yamashita K, Nomura M, Omura T, Kishida A, Furukawa H, Todo S. Dose-dependent study of a novel immunosuppressant, FTY720, with the canine renal allograft transplantation model. Transplant Proc 1999; 31:1208-9. [PMID: 10083540 DOI: 10.1016/s0041-1345(98)01967-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- T Suzuki
- Hokkaido University School of Medicine, Sapporo, Japan
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Yokota R, Tanaka M, Yamasaki K, Araki M, Miyamae M, Maeda T, Koga K, Yabuuchi Y, Sasayama S. Blockade of ATP-sensitive K+ channels attenuates preconditioning effect on myocardial metabolism in swine: myocardial metabolism and ATP-sensitive K+ channels. Int J Cardiol 1998; 67:225-36. [PMID: 9894703 DOI: 10.1016/s0167-5273(98)00257-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVE We investigated if blockade of ATP-sensitive K+ channels (KATP) abolishes the protective effect of ischemic preconditioning (IP) on myocardial metabolism and ischemia-induced reactive hyperemia (RH) in pigs. METHODS IP was elicited by a single cycle of 5 min occlusion and 5 min reperfusion of coronary artery, followed by 15 min of test ischemia and 120 min of reperfusion. Vehicle or the ATP-sensitive K+ channels (KATP) blocker, glibenclamide (3 or 6 mg/kg; G3 or G6) was administered before IP (groups; IP, G3+IP, G6+IP). As respective controls, the same treatment was performed in groups without IP (groups; C, G3, G6). Tissue levels of ATP, creatine phosphate (CP) and intracellular pH (pHi) in the area at risk were measured by 31P-nuclear magnetic resonance spectroscopy. RH after 5 min of preconditioning ischemia was assessed by regional myocardial blood flow. RESULTS ATP and pHi were preserved after 15 min of ischemia in the IP group [C/IP; ATP=57+/-4/76+/-10% of baseline, pHi=6.18+/-0.08/6.66+/-0.03, P<0.05, C vs. IP]. Both doses of glibenclamide completely abolished the ATP sparing effect of IP. The high dose completely abolished pHi preservation (G6+IP=6.33+/-0.06), while the low dose showed only a partial effect (G3+IP=6.48+/-0.03). Glibenclamide did not adversely affect myocardial metabolism in groups without IP. Glibenclamide attenuated RH after 5 min of ischemia by 30% in both subendocardium and subepicardium. CONCLUSIONS Blockade of KATP abolished the preconditioning effect on myocardial metabolism, and partially attenuated post-ischemic reactive hyperemia in pigs. These results indicate that KATP activation might be involved in the mechanisms of these phenomena, reactive hyperemia is not sufficient to induce IP protection.
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Affiliation(s)
- R Yokota
- Department of Internal Medicine, Faculty of Medicine, Kyoto University, Japan
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Tanaka M, Fujiwara H, Yamasaki K, Yokota R, Doyama K, Inada T, Ohtani S, Fujiwara T, Sasayama S. Expression of heat shock protein after ischemic preconditioning in rabbit hearts. Jpn Circ J 1998; 62:512-6. [PMID: 9707008 DOI: 10.1253/jcj.62.512] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Previous studies have shown that preconditioning (PC) with a brief ischemic episode induces heat shock protein (HSP) in cardiac tissue. However, it is unclear when and where in the left ventricle HSP is expressed after PC. Hence, the expression of HSP was studied in rabbit hearts at various time intervals after PC using immunohistochemical methods. Rabbits were preconditioned four times with 5 min of occlusion and 5 min of reperfusion of the coronary artery and then were killed at 0, 3, 24, 48, 72 and 168 h after the PC (n=4, for each time interval). Samples were obtained from the subendocardium and subepicardium of the preconditioned and nonpreconditioned wall and these were processed to 4 microm thick cryosections. The sections were immunolabelled with mouse monoclonal IgGs against HSP 72/73. Positive immunoreactivity was observed as early as 3 h after PC, persisting up to 72 h but not detected at 168 h. HSP was expressed not only in the preconditioned myocardium but also in the remote nonpreconditioned myocardium. There was a wide variation in expression among myocytes. Expression was dominant in myocytes compared with vessel walls. It was concluded that PC induced transient and inhomogeneous expression of HSP in rabbit hearts.
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Affiliation(s)
- M Tanaka
- The Third Division of Medicine, Kyoto University, Japan
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Abstract
Two subtypes of the thromboxane A2 (TxA2) receptor (TxA2R-E and TxA2R-P), which differ in their alternatively spliced cytoplasmic tails, have been identified. The initial concentration of the TxA2 mimetic IBOP required to reduce peak intracellular Ca2+ concentration ([Ca2+]i) induced by a second addition of IBOP (100 nmol/L) was similar (IC50 for TxA2R-E and TxA2R-P, 0.46 +/- 0.16 and 0.40 +/- 0.07 nmol/L) in fibroblasts overexpressing either the TxA2R-E or -P subtype. Although the number of TxA2 binding sites decreased in TxA2R-P cells after prolonged stimulation with a TxA2 mimetic, those in the TxA2R-E cells increased markedly. To determine whether the mechanism for desensitization differs between subtypes, the effect of activation of protein kinase C (PKC) or cAMP-dependent kinase on TxA2-induced [Ca2+]i mobilization was measured. Forskolin reduced the IBOP-induced peak [Ca2+]i in neither TxA2R-E nor TxA2R-P cells; however, treatment with phorbol esters (IC50, 0.57 +/- 0.70 nmol/L) strongly prevented IBOP-mediated [Ca2+]i rise in TxA2R-E but not in TxA2R-P cells. Desensitization of TxA2R-E by phorbol esters was prevented by the PKC inhibitor calphostin C or by downregulation of PKC-alpha. Thus, the response of TxA2R-E to prolonged stimulation differs from that of TxA2R-P in both the regulation of the number of binding sites and the mechanism for desensitization; agonists that activate PKC-alpha might interfere with TxA2R-E-mediated signaling.
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Affiliation(s)
- M Yukawa
- Vascular Biology Unit, Beth Israel Hospital, Boston, Mass, USA
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Yamasaki K, Fujiwara H, Tanaka M, Yokota R, Miyamae M, Ogawa J, Fujiwara T, Sasayama S. Preconditioning with 15-minute ischemia extends myocardial infarct size after subsequent 30-minute ischemia in rabbits. Jpn Circ J 1997; 61:344-52. [PMID: 9152787 DOI: 10.1253/jcj.61.344] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Ischemic preconditioning (PC) induced by 1 cycle of 5-min coronary occlusion and 5-min reperfusion limits infarct size (IS) after 30-min sustained ischemia in rabbits. The shortest ischemic period that induces the PC effect in rabbits is 3 min. To establish the maximum ischemic period to induce a beneficial PC effect, we examined the effect of PC periods of 10 and 15 min on IS after sustained ischemia. The IS in control rabbit hearts after 30 min of sustained occlusion of the left anterolateral coronary artery and 48-h reperfusion was compared with that of hearts treated as follows before being subjected to PC: 5-min occlusion and 5-min reperfusion; 10-min occlusion and 5-min reperfusion; or 15-min occlusion and 5-min reperfusion. In addition, the IS after 15-min or 45-min occlusion and 48-h reperfusion was measured. There was no significant difference in blood pressure, heart rate, or area at risk (AAR) among the rabbits in 5 groups. The IS measured histologically was 40 +/- 4% of AAR in the control, 10 +/- 3% after 5-min PC, and 12 +/- 2% after 10-min PC. However, in the 15-min PC group, the IS was 77 +/- 4% of AAR, which was significantly larger than that of the controls, but similar to that of hearts subjected to 45-min ischemia and reperfusion (67 +/- 3%). As 15 min of preconditioning ischemia alone caused small infarcts (18 +/- 1% of AAR), the infarcts caused by sustained ischemia per se in the 15-min PC group was estimated to be 72 +/- 5% of AAR, which was still significantly higher than in the control groups. We conclude that the maximum period of preconditioning ischemia that induces cardioprotection in rabbits is 10 min. When the ischemic period is longer than this, the IS after sustained ischemia is increased rather than restricted. However, the infarcted size in the 15-min PC group was not higher than that in the group subjected to 45-min continuous ischemia. This may be a major limitation for any clinical application of PC.
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Affiliation(s)
- K Yamasaki
- Department of Internal Medicine, Faculty of Medicine, Kyoto University, Japan
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Yokota R, Fujiwara H, Miyamae M, Tanaka M, Yamasaki K, Itoh S, Koga K, Yabuuchi Y, Sasayama S. Transient adenosine infusion before ischemia and reperfusion protects against metabolic damage in pig hearts. Am J Physiol 1995; 268:H1149-57. [PMID: 7900869 DOI: 10.1152/ajpheart.1995.268.3.h1149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We investigated whether transient adenosine (Ado) infusion before ischemia had the same effect on myocardial metabolism and function as ischemic preconditioning (IP). The control (C) group underwent 15 min of coronary artery occlusion followed by 120 min of reperfusion. The Ado group received a 15-min infusion of Ado (200 micrograms.kg-1.min-1) into the left atrium starting 20 min before ischemia. IP was elicited by two cycles of 5-min ischemia and 5-min reperfusion. In the area at risk, tissue levels of ATP, creatine phosphate (CP), and intracellular pH (pHi) were serially measured by 31P-nuclear magnetic resonance spectroscopy in 10 pigs from each group, and percent segment shortening (%SS) was measured in 7 pigs from each group. ATP and pHi were preserved after 15 min of ischemia in both Ado and IP groups [ATP = 64 +/- 7, 76 +/- 6, and 74 +/- 9% of baseline; pHi = 6.35 +/- 0.19, 6.54 +/- 0.11, and 6.64 +/- 0.11 in C, Ado, and IP groups, respectively (P < 0.05, Ado and IP vs. C)]. During reperfusion, ATP was restored progressively in both groups [71 +/- 7, 90 +/- 8, and 91 +/- 9% of baseline at 120 min of reperfusion in C, Ado, and IP groups, respectively (P < 0.05, Ado and IP vs. C)]. However, in contrast to the IP group, CP was not preserved during 15-min ischemia nor did it show persistent overshoot during reperfusion in the Ado group. There were no significant differences in %SS during ischemia and reperfusion among the three groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- R Yokota
- Department of Internal Medicine, Faculty of Medicine, Kyoto University, Japan
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Yokota R, Fujiwara H, Miyamae M, Tanaka M, Yamasaki K, Sasayama S, Itoh S, Koga K, Yabuuchi Y. Transient adenosine infusion and washout before ischemia protects the heart against myocardial damage during ischemia and reperfusion in pigs -energy metabolism and regional myocardial blood flow. Pathophysiology 1994. [DOI: 10.1016/0928-4680(94)90759-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Tanaka M, Fujiwara H, Yamasaki K, Miyamae M, Yokota R, Hasegawa K, Fujiwara T, Sasayama S. Ischemic preconditioning elevates cardiac stress protein but does not limit infarct size 24 or 48 h later in rabbits. Am J Physiol 1994; 267:H1476-82. [PMID: 7943394 DOI: 10.1152/ajpheart.1994.267.4.h1476] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We investigated whether ischemic preconditioning (PC) produced a second window of protection by delayed synthesis of cardioprotective proteins. Anesthetized open-chest rabbits were subjected to 30 min of coronary occlusion and 3 h of reperfusion. PC was elicited by 5 min of ischemia and was separated from sustained ischemia by 5 min, 2 h, or 24 h of reperfusion. Infarct size (% area at risk) was markedly limited by PC with 5 min of reperfusion when compared with controls (13.3 +/- 2.5 vs. 46.8 +/- 7.0%; P < 0.05). This protective effect was lost when the interval between PC and sustained ischemia was extended to 2 h (47.8 +/- 4.8%; P = NS vs. control) and did not reoccur even when it was extended to 24 h (44.2 +/- 6.5%; P = NS vs. sham-operated control). To potentiate induction of heat shock proteins (HSPs), a PC protocol involving four 5-min episodes of ischemia and reperfusion was also used and was separated from sustained ischemia by 24 or 48 h of reperfusion. However, neither of these protocols was protective, and limitation of infarct size was not observed (55.5 +/- 5.9 and 53.4 +/- 6.5% in 24 and 48 h of reperfusion, respectively; P = NS vs. corresponding sham-operated control). Myocardial expression of HSPs was examined using a monoclonal antibody against 72- to 73-kDa HSP in additional rabbits. Immunoreactivity was observed in the myocardium at 24 and 48 h after PC, but not immediately after PC.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M Tanaka
- Third Division of Medicine, Kyoto University, Japan
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Miyamae M, Fujiwara H, Kida M, Yokota R, Tanaka M, Katsuragawa M, Hasegawa K, Ohura M, Koga K, Yabuuchi Y. Preconditioning improves energy metabolism during reperfusion but does not attenuate myocardial stunning in porcine hearts. Circulation 1993; 88:223-34. [PMID: 8319337 DOI: 10.1161/01.cir.88.1.223] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND It has been reported that a brief period of coronary occlusion and reperfusion slows the rate of ATP depletion during subsequent sustained ischemia as well as limiting infarct size. However, it has not yet been determined whether ischemic preconditioning also has an effect on the functional and metabolic recovery of stunned myocardium. Our study was designed to address this problem. METHODS AND RESULTS Farm pigs were anesthetized with fluothane and randomly assigned to either a control group or a preconditioned group. The control group (n = 15) underwent 15 minutes of coronary occlusion followed by 120 minutes of reperfusion. The preconditioned group (n = 14) underwent two episodes of 5-minute occlusion and 5-minute reperfusion followed by 15 minutes of occlusion and 120 minutes of reperfusion. This protocol was designed to exclude the stunning effect of the preconditioning procedure itself as much as possible besides preconditioning the heart. A pair of ultrasonic crystals was implanted in the area at risk perfused by the left anterior descending coronary artery. 31P-nuclear magnetic resonance spectroscopy and sonomicrometry were performed alternately. Regional myocardial blood flow (RMBF) was determined with colored microspheres. At 15 minutes of sustained ischemia, phosphocreatine (Pcr), ATP, and intracellular pH were significantly better preserved in the preconditioned group (Pcr: control/preconditioned, 1 +/- 1%/14 +/- 1%; ATP:control/preconditioned, 66 +/- 2%/74 +/- 2%; pH:control/preconditioned, 6.32 +/- 0.07/6.52 +/- 0.05; P < .05). After reperfusion, ATP increased progressively and was almost normalized at 120 minutes of reperfusion in the preconditioned group (control/preconditioned, 73 +/- 4%/95 +/- 3%; P < .05). Overshoot of Pcr (which indicates that the energy generating system is operating better than energy utilizing system) persisted in preconditioned hearts but disappeared rapidly in controls (control/preconditioned, 104 +/- 3%/130 +/- 3% after 120 minutes of reperfusion). There was no significant difference in percent segment shortening (%SS), RMBF, and hemodynamics between the two groups throughout the experiment (%SS: control/preconditioned, 29.8 +/- 5.9%/28.8 +/- 6.3% of baseline after 120 minutes of reperfusion). CONCLUSIONS Preconditioning improves energy metabolism during reperfusion, although it does not attenuate myocardial stunning for at least 2 hours after reperfusion.
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Affiliation(s)
- M Miyamae
- Third Division, Faculty of Medicine, Kyoto University, Japan
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Fujii M, Asari T, Yokota R, Kobayashi T, Hasegawa H. Ageing effects on a new polymeric track detector SR-90 and a model of the nuclear track formation. ACTA ACUST UNITED AC 1993. [DOI: 10.1016/0969-8078(93)90047-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Arai Y, Yamauchi Y, Tsuji T, Fukasaku S, Yokota R, Kudo T. Spinal neurenteric cyst. Report of two cases and review of forty-one cases reported in Japan. Spine (Phila Pa 1976) 1992; 17:1421-4. [PMID: 1462222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Y Arai
- Department of Orthopaedic Surgery, Juntendo University School of Medicine, Tokyo, Japan
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