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Dive into the research topics where Keigo Hayashi is active.

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Featured researches published by Keigo Hayashi.


Organic Letters | 2011

Highly enantioselective and efficient synthesis of flavanones including pinostrobin through the rhodium-catalyzed asymmetric 1,4-addition.

Toshinobu Korenaga; Keigo Hayashi; Yusuke Akaki; Ryota Maenishi; Takashi Sakai

An efficient synthesis of bioactive chiral flavanones (1) was achieved through the Rh-catalyzed asymmetric 1,4-addition of arylboronic acid to chromone. The reaction in toluene proceeded smoothly at room temperature in the presence of 0.5% Rh catalyst with electron-poor chiral diphosphine MeO-F(12)-BIPHEP. In this reaction, the 1,2-addition to (S)-1 frequently occurred to yield (2S,4R)-2,4-diaryl-4-chromanol as a byproduct, which could be reduced by changing the reaction solvent to CH(2)Cl(2) to deactivate the Rh catalyst (3% required).


Internal Medicine | 2017

The Successful Treatment of Refractory Polyarteritis Nodosa Using Infliximab

Satoko Matsuo; Keigo Hayashi; Eisaku Morimoto; Ayako Kato; Ken Ei Sada; Haruki Watanabe; Mariko Takano-Narazaki; Katsue Sunahori-Watanabe; Tomoko Kawabata; Jun Wada

Polyarteritis nodosa (PAN), characterized by arteritis of medium-sized blood vessels, is usually treated with a combination of glucocorticoids and immunosuppressants; however, some cases are refractory to these treatments. We herein report the case of a man with PAN that was refractory to various immunosuppressive treatments, including cyclophosphamide, methotrexate, and rituximab. After infliximab (IFX) treatment was initiated, his symptoms improved dramatically and remission was maintained. IFX is considered to be an effective alternative treatment for PAN which proves to be refractory to several immunosuppressive treatments.


Internal Medicine | 2019

Hemoptysis Originating from the Bronchial Artery in Takayasu Arteritis with Ulcerative Colitis

Ryota Imamura; Keigo Hayashi; Ken Ei Sada; Yuriko Yamamura; Satoshi Yamaguchi; Michiko Morishita; Haruki Watanabe; Yoshinori Matsumoto; Jun Wada

Takayasu arteritis (TAK) is a large-vessel vasculitis affecting the aorta and its main branches. Hemoptysis can be experienced as the respiratory manifestation, but origination from a bronchial artery is rare. Ulcerative colitis (UC) shares genetic similarities with TAK; HLA-B52*01 is associated with TAK and UC. We herein report a patient who presented with hemoptysis from the right bronchial artery and was diagnosed with TAK during the follow-up of UC. Transcatheter embolization was performed, and prednisolone and tocilizumab induced remission. Complication of TAK should be considered in the clinical course of HLA-B52-positive UC patients, and tocilizumab may be a treatment option.


Modern Rheumatology Case Reports | 2018

Lymphoproliferative disease in a patient with Takayasu arteritis and ulcerative colitis

Yosuke Asano; Ken Ei Sada; Keigo Hayashi; Yuriko Yamamura; Sumie Hiramatsu; Keiji Ohashi; Yoshia Miyawaki; Michiko Morishita; Haruki Watanabe; Yoshinori Matsumoto; Tomoko Kawabata; Noriyuki Tanaka; Sakiko Hiraoka; Jun Wada

Abstract Lymphoproliferative disorders (LPDs) are sometimes found in patients with autoimmune diseases receiving immunosuppressive treatments. However, LPDs in patients with Takayasu arteritis (TAK) were not reported previously. A 41-year-old woman with TAK and ulcerative colitis (UC) maintained remission with 5 mg/day of prednisolone (PSL) and 100 mg/day of azathioprine (AZA). However, the follow up colonoscopy showed reddish, submucosal lesion in the rectum, and histological examination revealed medium-to-large-sized atypical lymphocytes proliferating in the mucosal layer. These lymphoid cells were CD20 positive and Epstein–Barr encoding region (EBER) positive, demonstrating EB virus-associated LPD. After the diagnosis, AZA was discontinued and rituximab (RTX) was initiated for treatment of both LPD and TAK. A follow-up colonoscopy after three months showed no abnormal findings and the remission of both UC and TAK was maintained. As an increased risk of LPD has been reported in patients with inflammatory bowel disease receiving thiopurines, LPD in our case might be related with complication of UC and use of AZA. RTX might be one of the treatment options for cases with TAK complicating other iatrogenic immunodeficiency-associated LPD.


Lupus | 2018

Refractory neuromyelitis optica spectrum disorder in systemic lupus erythematosus successfully treated with rituximab

K Shidahara; Keigo Hayashi; Ken Ei Sada; Sumie Hiramatsu; Michiko Morishita; Haruki Watanabe; Yoshinori Matsumoto; Tomoko Kawabata; Jun Wada

We present a case of a woman with systemic lupus erythematosus (SLE) who had refractory episodes of neuromyelitis optica spectrum disorder (NMOSD) and was successfully treated with rituximab. She was positive for anti-aquaporin-4 (AQP4) antibody and had typical cranial and longitudinally extended spinal lesions but no optic nerve involvement. There is no established treatment for NMOSD/SLE overlap cases. Our experience suggests that rituximab may be effective for patients with combined SLE and anti-AQP4 antibody-positive NMOSD.


Lupus | 2018

Progressive reduction of serum complement levels: a risk factor for relapse in patients with hypocomplementemia in systemic lupus erythematosus:

Y Miyawaki; Ken Ei Sada; Y Asano; Keigo Hayashi; Y Yamamura; Sumie Hiramatsu; K Ohashi; Michiko Morishita; Haruki Watanabe; Yoshinori Matsumoto; Tomoko Kawabata; Jun Wada

Objective Serologically active clinically quiescent (SACQ)-SLE is a subtype of systemic lupus erythematosus (SLE); most SACQ-SLE patients relapse. Although complement and/or anti-dsDNA level fluctuations during SACQ status are reportedly not useful for predicting relapse, they might be useful in specific clinical settings. We aimed to assess the correlation between future relapse and progressive reductions in serum complement levels following remission in patients with hypocomplementemia. Methods We retrospectively reviewed patients aged ≥15 years who were treated with ≥20 mg/day of prednisolone for remission induction. After achieving remission, the patients treated with prednisolone tapered to ≤15 mg/day without relapse and followed by hypocomplementemia (first hypocomplementemia point) were analyzed. The primary outcome was the relapse during the first 24 months. Results Seventy-six patients were enrolled; 31 (40.8%) relapsed. A ≥10% reduction after the first hypocomplementemia point in serum C3, C4, and CH50 levels was found in 10, 21, and 16 patients, respectively. Hazard ratios (95% confidence intervals) for relapse were 2.32 (0.92–5.12) for serum C3 levels and 2.46 (1.18–5.01) for serum C4 levels. Progressive reductions in serum C3 and C4 levels had relatively high specificity (93.3% and 82.2%) but limited sensitivity (22.6% and 41.9%) for predicting relapse. However, simultaneous progressive reduction in C3 levels and increase in anti-dsDNA antibody levels had the highest specificity (97.8%), and simultaneous progressive reduction in C4 levels or increase in anti-dsDNA antibody levels had the highest sensitivity (71.0%). Conclusion Simultaneous progressive reductions in complement levels and increases in anti-dsDNA antibody levels may indicate future relapse SACQ-SLE patients.


Advanced Synthesis & Catalysis | 2010

Highly Active and Enantioselective Rhodium‐Catalyzed Asymmetric 1,4‐Addition of Arylboronic Acid to α,β‐ Unsaturated Ketone by using Electron‐Poor MeO‐F12‐BIPHEP

Toshinobu Korenaga; Ryota Maenishi; Keigo Hayashi; Takashi Sakai


Journal of the Neurological Sciences | 2018

A mild myopathy with anti-SRP plus anti-PL-12 antibodies successfully treated by oral steroid monotherapy

Koh Tadokoro; Yasuyuki Ohta; Ryo Sasaki; Yoshiaki Takahashi; Kota Sato; Jingwei Shang; Mami Takemoto; Nozomi Hishikawa; Toru Yamashita; Keigo Hayashi; Michiko Morishita; Ichizo Nishino; Koji Abe


Journal of Medical Case Reports | 2018

An open-label pilot study on preventing glucocorticoid-induced diabetes mellitus with linagliptin

Yoshia Miyawaki; Ken Ei Sada; Yosuke Asano; Keigo Hayashi; Yuriko Yamamura; Sumie Hiramatsu; Keiji Ohashi; Michiko Morishita; Haruki Watanabe; Yoshinori Matsumoto; Katsue Sunahori-Watanabe; Tomoko Kawabata; Jun Wada


Jcr-journal of Clinical Rheumatology | 2018

Cluster Analysis Using Anti–Aminoacyl-tRNA Synthetases and SS-A/Ro52 antibodies in Patients With Polymyositis/Dermatomyositis

Keiji Ohashi; Ken Ei Sada; Yu Nakai; Shun Matsushima; Yosuke Asano; Keigo Hayashi; Yuriko Yamamura; Sumie Hiramatsu; Yoshia Miyawaki; Michiko Morishita; Takayuki Katsuyama; Eri Katsuyama; Haruki Watanabe; Noriko Tatebe; Mariko Narazaki; Yoshinori Matsumoto; Katsue Sunahori Watanabe; Tomoko Kawabata; Jun Wada

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