Koichiro Tahara
Tokyo Medical University
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Koichiro Tahara.
Immunopharmacology | 2000
Toshihiko Hirano; Norioki Tsuboi; Masato Homma; Kitaro Oka; Tohru Takekoshi; Koichiro Tahara; Hirofumi Takanashi; Haruo Abe; Yukitomo Urata; Tohru Hayashi
We compared lymphocyte-suppressive potencies of prednisolone and methylprednisolone in rheumatoid arthritis (RA). IC(50)s of the glucocorticoids (GCs) on concanavalin A-induced blastogenesis of peripheral-blood mononuclear cells (PBMCs) from 44 RA patients and 30 healthy subjects were estimated in vitro, and differences in the IC(50)s of the two GCs were evaluated. The mean (+/-SD) IC(50)s for prednisolone and methylprednisolone on PBMC-blastogenesis of RA were 17.2+/-17.1 and 12.6+/-18.4 ng/ml, respectively, and no significant differences were observed between prednisolone-IC(50) and methylprednisolone-IC(50). In contrast, the mean IC(50)s of prednisolone and methylprednisolone on healthy PBMCs were 19.4+/-22. 4 and 3.7+/-3.9 ng/ml, respectively, and thus methylprednisolone potency was significantly higher than prednisolone potency (p<0.01). Methylprednisolone potency against PBMCs in RA patients exhibiting a high level of rheumatoid factor (RF) (>20 IU/ml) and the rheumatoid arthritis particle-agglutination value (RAPA) (>80) was significantly higher than that of patients exhibiting a lower level of RF or RAPA (p<0.05). In prednisolone-IC(50), however, such differences between the two patient-subgroups were not observed. Unlike reported cases of renal transplantation and healthy subjects, there was no difference in the lymphocyte-suppressive potencies for both prednisolone and methylprednisolone on RA-PBMCs. However, PBMCs from RA patients exhibiting high levels of RF or RAPA are more sensitive to methylprednisolone rather than prednisolone.
Modern Rheumatology | 2014
Eri Kimura; Takeyuki Kanzaki; Koichiro Tahara; Haeru Hayashi; Shiori Hashimoto; Akari Suzuki; Ryo Yamada; Kazuhiko Yamamoto; Tetsuji Sawada
Abstract Objectives. Cellular fibronectin (cFn) has been implicated in the pathogenesis of rheumatoid arthritis (RA), and we previously demonstrated the presence of citrullinated cFn in rheumatoid synovial tissues. The present study aimed to investigate whether citrullinated cFn can be detected in the plasma or synovial fluid of RA patients. Methods. Twenty-five rheumatoid arthritis synovial fluid (RASF), seven osteoarthritis synovial fluid (OASF) and 12 plasma samples from RA patients were examined. Citrullination of cFn was determined by immunoprecipitation (IP), western blotting and enzyme-linked immunosorbent assay (ELISA), in which peptidyl-citrulline within cFn was detected using a specific anti-cFn monoclonal antibody in combination with anti-modified citrulline antibody after chemical modification. Results. Levels of citrullination associated with cFn, as determined by ELISA, were significantly higher in RASF than in OASF samples. IP and western blotting detected citrullinated cFn in RASF but not in plasma samples from RA patients. Levels of total cFn were elevated in RASF compared with OASF, and 24 out of 25 RASF samples were positive for anti-CCP antibody. However, no correlation was observed between levels of citrullinated cFn and those of total cFn or anti-CCP antibody in RASF. On the other hand, a significant positive correlation was observed between the levels of matrix metalloproteinase-3 (MMP-3) and cFn citrullination in RASF. Conclusions. Citrullinated cFn appears to be produced within the affected joint and might be involved in the pathogenesis of rheumatoid synovitis.
Rheumatology International | 2011
Aki Shoji; Koichiro Tahara; Haeru Hayashi; Soichiro Tsuji; Eri Kimura; Kengo Yamamoto; Masato Odawara; Tetsuji Sawada
We report a 34-year-old female case of diffuse systemic sclerosis (SSc) with generalized ectopic calcification, who developed severe headache with vertical atlantoaxial subluxation (AAS) complicated by calcification around the odontoid process (crowned dens pattern calcification). Although a rare complication, AAS should be considered as a differential diagnosis of severe headache in SSc patients with extensive calcification.
International Journal of Rheumatic Diseases | 2017
Eri Kato; Tetsuji Sawada; Koichiro Tahara; Haeru Hayashi; Mayu Tago; Hiroaki Mori; Jinju Nishino; Toshihiro Matsui; Shigeto Tohma
To determine whether the age at onset of rheumatoid arthritis (RA) has increased in Japan using a nationwide database (National Database of Rheumatic Diseases by iR‐net in Japan, NinJa).
Internal Medicine | 2019
Yuki Matsumoto; Haeru Hayashi; Koichiro Tahara; Takuya Yasuda; Shoko Tsubouchi; Yusuke Yamamoto; Takahiro Mizuuchi; Hiroaki Mori; Tetsuji Sawada
Gastric antral vascular ectasia (GAVE) is a rare cause of chronic gastric hemorrhaging and iron deficiency anemia and is characterized by a distinctive endoscopic appearance. The main treatment of GAVE is endoscopic; however, medication is necessary in refractory cases. We herein report a 69-year-old woman with systemic sclerosis (SSc) who developed recurrent severe anemia after endoscopic treatment of GAVE that was successfully managed using intravenous cyclophosphamide (IVCY). The recurrence of GAVE after discontinuation of IVCY was successfully managed using a combination of IVCY and endoscopic treatment, without blood transfusion. Long-term IVCY may be indicated for refractory GAVE associated with SSc.
Internal Medicine | 2018
Eri Kato; Koichiro Tahara; Haeru Hayashi; Aki Shoji; Hiroaki Mori; Tetsuji Sawada
Central nervous system (CNS) involvement in granulomatosis with polyangiitis (GPA), including pachymeningitis and CNS vasculitis, is uncommon. Although intracerebral hemorrhage (ICH) has been reported in GPA, simultaneous multiple ICH (SMICH) is rare. We describe the case of a 50-year-old woman with a history of a limited form of GPA with chronic pachymeningitis who presented with acute-onset headache accompanied by nausea and vomiting, and who developed consciousness impairment. Computed tomography revealed bilateral subcortical ICH. Sinus thrombosis was not apparent on angiography. The patient was treated with high-dose corticosteroid therapy. The cause of the steroid-responsive SMICH in this case was unknown, but it might have been CNS vasculitis. Patients with GPA may present with SMICH, which is considered an indication for immunosuppressive therapy.
The Journal of Rheumatology | 2004
Kenji Onda; Emiko Rimbara; Toshihiko Hirano; Kitaro Oka; Haruo Abe; Koichiro Tahara; Hirofumi Takanashi; Norioki Tsuboi; Tomoyuki Niitsuma; Tohru Hayashi
Modern Rheumatology | 2004
Haruo Abe; Norioki Tsuboi; Sonosuke Yukawa; Souichirou Tsuji; Haeru Hayashi; Naoichiro Yukawa; Hirofumi Takanashi; Koichiro Tahara; Norihiko Tonozuka; Tohru Hayashi
Clinical Rheumatology | 2008
Koichiro Tahara; Sonosuke Yukawa; Aki Shoji; Haeru Hayashi; Norioki Tsuboi
Modern Rheumatology | 2008
Sonosuke Yukawa; Koichiro Tahara; Naoichiro Yukawa; Aki Shoji; Soichiro Tsuji; Haeru Hayashi; Norioki Tsuboi