Tokumasu, Kazuki - OU Author List - OKAYAMA UNIVERSITY SCIENTIFIC ACHIEVEMENT REPOSITORY

Mycobacterium intracellulare Infection in a Japanese Patient with Signal Transducer and Activator of Transcription-3 Gain-of-function Syndrome

FullText URL	fulltext.pdf
Author	Hagiya, Hideharu\| Soejima, Yoshiaki\| Tokumasu, Kazuki\| Hirai, Yoji\| Otsuka, Yuki\| Kawaguchi, Marina\| Fukushima, Shinnosuke\| Nakamoto, Kenta\| Oguni, Kohei\| Shiode, Yusuke\| Uda, Kazuhiro\| Yashiro, Masato\| Hasegawa, Kousei\| Iio, Koji\| Otsuka, Fumio\|
Keywords	inborn errors of immunity Mycobacterium avium complex nontuberculous mycobacteria primary immunodeficiency syndrome signal transducer and activator of transcription-3
Published Date	2026-05-15
Publication Title	Internal Medicine
Volume	volume65
Issue	issue10
Publisher	Japanese Society of Internal Medicine
Start Page	1421
End Page	1430
ISSN	0918-2918
NCID	AA10827774
Content Type	Journal Article
language	English
OAI-PMH Set	岡山大学
Copyright Holders	© 2026 by The Japanese Society of Internal Medicine
File Version	publisher
PubMed ID	41034003
DOI	10.2169/internalmedicine.6174-25
Web of Science KeyUT	001586962100001
Related Url	isVersionOf https://doi.org/10.2169/internalmedicine.6174-25

Exploratory Analysis of Serum IGF-I Levels and Symptom Trajectories in Long COVID During the Omicron Period

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Author	Suyama, Atsuhito\| Otsuka, Yuki\| Nakano, Yasuhiro\| Tokumasu, Kazuki\| Sakurada, Yasue\| Matsuda, Yui\| Honda, Hiroyuki\| Soejima, Yoshiaki\| Hasegawa, Toru\| Takase, Ryosuke\| Omura, Daisuke\| Oguni, Kohei\| Ueda, Keigo\| Otsuka, Fumio\|
Keywords	COVID-19 fatigue IGF-I long COVID recovery
Published Date	2026-05-11
Publication Title	Journal of Clinical Medicine
Volume	volume15
Issue	issue10
Publisher	MDPI AG
Start Page	3702
ISSN	2077-0383
Content Type	Journal Article
language	English
OAI-PMH Set	岡山大学
Copyright Holders	© 2026 by the authors.
File Version	publisher
PubMed ID	42194664
DOI	10.3390/jcm15103702
Web of Science KeyUT	001776414600001
Related Url	isVersionOf https://doi.org/10.3390/jcm15103702

Possible Involvement of Hypothalamic Dysfunction in Long COVID Patients Characterized by Delayed Response to Gonadotropin-Releasing Hormone

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Author	Otsuka, Yuki\| Soejima, Yoshiaki\| Nakano, Yasuhiro\| Suyama, Atsuhito\| Takase, Ryosuke\| Oguni, Kohei\| Masuda, Yohei\| Omura, Daisuke\| Sakurada, Yasue\| Matsuda, Yui\| Hasegawa, Toru\| Honda, Hiroyuki\| Tokumasu, Kazuki\| Ueda, Keigo\| Otsuka, Fumio\|
Keywords	COVID-19 gonadotropin gonadotropin-releasing hormone (GnRH) hypothalamus long COVID
Published Date	2026-01-14
Publication Title	International Journal of Molecular Sciences
Volume	volume27
Issue	issue2
Publisher	MDPI AG
Start Page	832
ISSN	1422-0067
Content Type	Journal Article
language	English
OAI-PMH Set	岡山大学
Copyright Holders	© 2026 by the authors.
File Version	publisher
PubMed ID	001670615000001
DOI	10.3390/ijms27020832
Web of Science KeyUT	001670615000001
Related Url	isVersionOf https://doi.org/10.3390/ijms27020832

Clinical Utility of SARS-CoV-2 Antibody Titers in the Management of Patients With Long COVID Infected With the Omicron Variant

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Author	Kawaguchi, Marina\| Sakurada, Yasue\| Tokumasu, Kazuki\| Otsuka, Yuki\| Nakano, Yasuhiro\| Matsuda, Yui\| Honda, Hiroyuki\| Omura, Daisuke\| Matsuki, Nobuyoshi\| Furukawa, Masanori\| Higashikage, Akihito\| Otsuka, Fumio\|
Keywords	brain fog COVID-19 long COVID Omicron variants SARS-CoV-2 antibodies
Published Date	2026-04-22
Publication Title	British Journal of Biomedical Science
Volume	volume83
Publisher	Frontiers Media SA
Start Page	16255
ISSN	2474-0896
Content Type	Journal Article
language	English
OAI-PMH Set	岡山大学
Copyright Holders	© 2026 Kawaguchi, Sakurada, Tokumasu, Otsuka, Nakano, Matsuda, Honda, Omura, Matsuki, Furukawa, Higashikage and Otsuka.
File Version	publisher
DOI	10.3389/bjbs.2026.16255
Web of Science KeyUT	001757232800001
Related Url	isVersionOf https://doi.org/10.3389/bjbs.2026.16255

Clinical Evaluation of Oxidative Stress Markers in Patients with Long COVID During the Omicron Phase in Japan

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Author	Mese, Osamu\| Otsuka, Yuki\| Sakurada, Yasue\| Tokumasu, Kazuki\| Soejima, Yoshiaki\| Morita, Satoru\| Nakano, Yasuhiro\| Honda, Hiroyuki\| Eguchi, Akiko\| Fukuda, Sanae\| Nojima, Junzo\| Otsuka, Fumio\|
Keywords	biological antioxidant potential (BAP) Coronavirus disease 2019 (COVID-19) diacron-reactive oxygen metabolites (d-ROM) Long COVID oxidative stress index (OSI)
Published Date	2025-08-30
Publication Title	Antioxidants
Volume	volume14
Issue	issue9
Publisher	MDPI AG
Start Page	1068
ISSN	2076-3921
Content Type	Journal Article
language	English
OAI-PMH Set	岡山大学
Copyright Holders	© 2025 by the authors.
File Version	publisher
PubMed ID	41008975
DOI	10.3390/antiox14091068
Web of Science KeyUT	001579416500001
Related Url	isVersionOf https://doi.org/10.3390/antiox14091068

Clinical Characteristics of Vitamin D Deficiency Detected in Long COVID Patients During the Omicron Phase

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Author	Matsuda, Yui\| Sakurada, Yasue\| Nakano, Yasuhiro\| Otsuka, Yuki\| Tokumasu, Kazuki\| Honda, Hiroyuki\| Soejima, Yoshiaki\| Yokota, Yuya\| Takase, Ryosuke\| Omura, Daisuke\| Otsuka, Fumio\|
Keywords	COVID-19 25-hydroxyvitamin D long COVID palpitation vitamin D deficiency
Published Date	2025-05-16
Publication Title	Nutrients
Volume	volume17
Issue	issue10
Publisher	MDPI AG
Start Page	1692
ISSN	2072-6643
Content Type	Journal Article
language	English
OAI-PMH Set	岡山大学
Copyright Holders	© 2025 by the authors.
File Version	publisher
PubMed ID	40431432
DOI	10.3390/nu17101692
Web of Science KeyUT	001495601700001
Related Url	isVersionOf https://doi.org/10.3390/nu17101692

Impact of Lifestyle Changes on Body Weight Gain During Nationwide Lockdown Due to COVID-19 Pandemic

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Author	Nishida, Chisa\| Honda, Hiroyuki\| Otsuka, Yuki\| Hagiya, Hideharu\| Nakano, Yasuhiro\| Oguni, Kohei\| Tokumasu, Kazuki\| Sakurada, Yasue\| Obika, Mikako\| Otsuka, Fumio\|
Keywords	COVID-19 pandemic lockdown weight gain medical check-ups lifestyle
Published Date	2025-03-25
Publication Title	Journal of Clinical Medicine
Volume	volume14
Issue	issue7
Publisher	MDPI
Start Page	2242
ISSN	2077-0383
Content Type	Journal Article
language	English
OAI-PMH Set	岡山大学
Copyright Holders	© 2025 by the authors.
File Version	publisher
PubMed ID	40217694
DOI	10.3390/jcm14072242
Web of Science KeyUT	001463577200001
Related Url	isVersionOf https://doi.org/10.3390/jcm14072242

Involvement of a Novel Variant of FGFR1 Detected in an Adult Patient with Kallmann Syndrome in Regulation of Gonadal Steroidogenesis

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Author	Soejima, Yoshiaki\| Otsuka, Yuki\| Kawaguchi, Marina\| Oguni, Kohei\| Yamamoto, Koichiro\| Nakano, Yasuhiro\| Yasuda, Miho\| Tokumasu, Kazuki\| Ueda, Keigo\| Hasegawa, Kosei\| Iwata, Nahoko\| Otsuka, Fumio\|
Keywords	fibroblast growth factor receptor 1 (FGFR1) gynecomastia Kallmann syndrome (KS) osteoporosis and steroidogenesis
Published Date	2025-03-18
Publication Title	International Journal of Molecular Sciences
Volume	volume26
Issue	issue6
Publisher	MDPI
Start Page	2713
ISSN	1661-6596
Content Type	Journal Article
language	English
OAI-PMH Set	岡山大学
Copyright Holders	© 2025 by the authors.
File Version	publisher
PubMed ID	40141355
DOI	10.3390/ijms26062713
Web of Science KeyUT	001452479200001
Related Url	isVersionOf https://doi.org/10.3390/ijms26062713

Course of General Fatigue in Patients with Post-COVID-19 Conditions Who Were Prescribed Hochuekkito: A Single-Center Exploratory Pilot Study

FullText URL	fulltext.pdf
Author	Tokumasu, Kazuki\| Matsuki, Nobuyoshi\| Otsuka, Yuki\| Sakamoto, Yoko\| Ueda, Keigo\| Matsuda, Yui\| Sakurada, Yasue\| Honda, Hiroyuki\| Nakano, Yasuhiro\| Hasegawa, Toru\| Takase, Ryosuke\| Omura, Daisuke\| Otsuka, Fumio\|
Keywords	fatigue assessment scale (FAS) general fatigue hochuekkito kampo medicine long COVID post-COVID-19 condition
Published Date	2025-02-19
Publication Title	Journal of Clinical Medicine
Volume	volume14
Issue	issue4
Publisher	MDPI
Start Page	1391
ISSN	2077-0383
Content Type	Journal Article
language	English
OAI-PMH Set	岡山大学
Copyright Holders	© 2025 by the authors.
File Version	publisher
PubMed ID	40004921
DOI	10.3390/jcm14041391
Web of Science KeyUT	001429605100001
Related Url	isVersionOf https://doi.org/10.3390/jcm14041391

Interrelationships Between Plasma Levels of Brain Natriuretic Peptide and Prolonged Symptoms Due to Long COVID

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Author	Masuda, Yohei\| Otsuka, Yuki\| Tokumasu, Kazuki\| Honda, Hiroyuki\| Sakurada, Yasue\| Matsuda, Yui\| Nakano, Yasuhiro\| Takase, Ryosuke\| Omura, Daisuke\| Hasegawa, Toru\| Ueda, Keigo\| Otsuka, Fumio\|
Keywords	brain fog brain natriuretic peptide (BNP) COVID-19 fatigue long COVID memory impairment post-COVID-19 conditions
Published Date	2025-01-26
Publication Title	Journal of Clinical Medicine
Volume	volume14
Issue	issue3
Publisher	MDPI
Start Page	817
ISSN	2077-0383
Content Type	Journal Article
language	English
OAI-PMH Set	岡山大学
Copyright Holders	© 2025 by the authors.
File Version	publisher
PubMed ID	39941487
DOI	10.3390/jcm14030817
Web of Science KeyUT	001420254400001
Related Url	isVersionOf https://doi.org/10.3390/jcm14030817

Phase-dependent trends in the prevalence of myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS) related to long COVID: A criteria-based retrospective study in Japan

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Author	Morita, Satoru\| Tokumasu, Kazuki\| Otsuka, Yuki\| Honda, Hiroyuki\| Nakano, Yasuhiro\| Sunada, Naruhiko\| Sakurada, Yasue\| Matsuda, Yui\| Soejima, Yoshiaki\| Ueda, Keigo\| Otsuka, Fumio\|
Published Date	2024-12-09
Publication Title	PLoS ONE
Volume	volume19
Issue	issue12
Publisher	Public Library of Science
Start Page	e0315385
ISSN	1932-6203
Content Type	Journal Article
language	English
OAI-PMH Set	岡山大学
Copyright Holders	© 2024 Morita et al.
File Version	publisher
PubMed ID	39652555
DOI	10.1371/journal.pone.0315385
Web of Science KeyUT	001373564500009
Related Url	isVersionOf https://doi.org/10.1371/journal.pone.0315385

Postgraduate Year Two Medical Residents' Awareness of Personal Development as a Physician during the Management of Inpatients: A Qualitative Study

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Author	Tokumasu, Kazuki\| Obara, Haruo\| Hirosawa, Takanobu\| Ogawa, Hiroko\| Otsuka, Fumio\|
Keywords	autonomy personal development personal growth qualitative study responsibility
Published Date	2024-08-14
Publication Title	Healthcare
Volume	volume12
Issue	issue16
Publisher	MDPI
Start Page	1621
ISSN	2227-9032
Content Type	Journal Article
language	English
OAI-PMH Set	岡山大学
Copyright Holders	© 2024 by the authors.
File Version	publisher
PubMed ID	39201179
DOI	10.3390/healthcare12161621
Web of Science KeyUT	001304820900001
Related Url	isVersionOf https://doi.org/10.3390/healthcare12161621

Importance of Blood Glucose Measurement for Predicting the Prognosis of Long COVID: A Retrospective Study in Japan

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Author	Yokoyama, Sho\| Honda, Hiroyuki\| Otsuka, Yuki\| Tokumasu, Kazuki\| Nakano, Yasuhiro\| Sakurada, Yasue\| Matsuda, Yui\| Sunada, Naruhiko\| Hasegawa, Toru\| Takase, Ryosuke\| Omura, Daisuke\| Soejima, Yoshiaki\| Ueda, Keigo\| Kishida, Masayuki\| Otsuka, Fumio\|
Keywords	blood glucose diabetes mellitus long COVID omicron variant post-COVID-19 condition
Published Date	2024-07-13
Publication Title	Journal of Clinical Medicine
Volume	volume13
Issue	issue14
Publisher	MDPI
Start Page	4099
ISSN	2077-0383
Content Type	Journal Article
language	English
OAI-PMH Set	岡山大学
Copyright Holders	© 2024 by the authors.
File Version	publisher
PubMed ID	39064139
DOI	10.3390/jcm13144099
Web of Science KeyUT	001278836700001
Related Url	isVersionOf https://doi.org/10.3390/jcm13144099

Clinical and endocrine features of orthostatic intolerance detected in patients with long COVID

FullText URL	fulltext.pdf
Author	Kato, Atsushi\| Tokumasu, Kazuki\| Yamamoto, Koichiro\| Otsuka, Yuki\| Nakano, Yasuhiro\| Honda, Hiroyuki\| Sunada, Naruhiko\| Sakurada, Yasue\| Matsuda, Yui\| Hasegawa, Toru\| Takase, Ryosuke\| Ueda, Keigo\| Otsuka, Fumio\|
Keywords	Active standing test Long COVID Orthostatic intolerance Post COVID-19 condition Postural orthostatic tachycardia syndrome (POTS)
Published Date	2024-07-24
Publication Title	Scientific Reports
Volume	volume14
Issue	issue1
Publisher	Nature Portfolio
Start Page	17025
ISSN	2045-2322
Content Type	Journal Article
language	English
OAI-PMH Set	岡山大学
Copyright Holders	© The Author(s) 2024
File Version	publisher
PubMed ID	39043760
DOI	10.1038/s41598-024-67815-y
Web of Science KeyUT	001275757700007
Related Url	isVersionOf https://doi.org/10.1038/s41598-024-67815-y

Changes in Working Situations of Employed Long COVID Patients: Retrospective Study in Japanese Outpatient Clinic

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Author	Matsuda, Yui\| Sakurada, Yasue\| Otsuka, Yuki\| Tokumasu, Kazuki\| Nakano, Yasuhiro\| Sunada, Naruhiko\| Honda, Hiroyuki\| Hasegawa, Toru\| Takase, Ryosuke\| Omura, Daisuke\| Ueda, Keigo\| Otsuka, Fumio\|
Keywords	employment job retirement leave of absence long COVID omicron variant post-COVID-19 condition
Published Date	2024-06-28
Publication Title	Journal of Clinical Medicine
Volume	volume13
Issue	issue13
Publisher	MDPI
Start Page	3809
ISSN	2077-0383
Content Type	Journal Article
language	English
OAI-PMH Set	岡山大学
Copyright Holders	© 2024 by the authors.
File Version	publisher
PubMed ID	38999375
DOI	10.3390/jcm13133809
Web of Science KeyUT	001269802900001
Related Url	isVersionOf https://doi.org/10.3390/jcm13133809

Occult endocrine disorders newly diagnosed in patients with post-COVID-19 symptoms

FullText URL	fulltext.pdf
Author	Nakano, Yasuhiro\| Sunada, Naruhiko\| Tokumasu, Kazuki\| Honda, Hiroyuki\| Otsuka, Yuki\| Sakurada, Yasue\| Matsuda, Yui\| Hasegawa, Toru\| Omura, Daisuke\| Ochi, Kanako\| Yasuda, Miho\| Hagiya, Hideharu\| Ueda, Keigo\| Otsuka, Fumio\|
Keywords	Diabetes mellitus Endocrine disorders Long COVID Metabolic disorders Thyroid disease
Note	The version of record of this article, first published in Scientific Reports, is available online at Publisher’s website: http://dx.doi.org/10.1038/s41598-024-55526-3\|
Published Date	2024-03-05
Publication Title	Scientific Reports
Volume	volume14
Issue	issue1
Publisher	Nature Portfolio
Start Page	5446
ISSN	2045-2322
Content Type	Journal Article
language	English
OAI-PMH Set	岡山大学
Copyright Holders	© The Author(s) 2024
File Version	publisher
PubMed ID	38443459
DOI	10.1038/s41598-024-55526-3
Web of Science KeyUT	001180457200009
Related Url	isVersionOf https://doi.org/10.1038/s41598-024-55526-3

Characteristics of Functional Hyperthermia Detected in an Outpatient Clinic for Fever of Unknown Origin

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Author	Oka, Kosuke\| Tokumasu, Kazuki\| Hagiya, Hideharu\| Otsuka, Fumio\|
Keywords	C-reactive protein (CRP) fever of unknown origin (FUO) functional hyperthermia (FH) psychiatric disorder psychogenic fever
Published Date	2024-02-03
Publication Title	Journal of Clinical Medicine
Volume	volume13
Issue	issue3
Publisher	MDPI
Start Page	889
ISSN	2077-0383
Content Type	Journal Article
language	English
OAI-PMH Set	岡山大学
Copyright Holders	© 2024 by the authors.
File Version	publisher
PubMed ID	38337583
DOI	10.3390/jcm13030889
Web of Science KeyUT	001159108700001
Related Url	isVersionOf https://doi.org/10.3390/jcm13030889

Clinical characteristics of female long COVID patients with menstrual symptoms: a retrospective study from a Japanese outpatient clinic

FullText URL	fulltext.pdf
Author	Sakurada, Yasue\| Matsuda, Yui\| Motohashi, Kanon\| Hasegawa, Toru\| Otsuka, Yuki\| Nakano, Yasuhiro\| Tokumasu, Kazuki\| Yamamoto, Koichiro\| Sunada, Naruhiko\| Honda, Hiroyuki\| Hagiya, Hideharu\| Ueda, Keigo\| Otsuka, Fumio\|
Keywords	Depression fatigue menstrual symptoms omicron variant post-COVID-19 condition
Published Date	2024-01-25
Publication Title	Journal of Psychosomatic Obstetrics & Gynecology
Volume	volume45
Issue	issue1
Publisher	Taylor and Francis
Start Page	2305899
ISSN	0167-482X
Content Type	Journal Article
language	English
OAI-PMH Set	岡山大学
Copyright Holders	© 2024 The Author(s).
File Version	publisher
PubMed ID	38270210
DOI	10.1080/0167482X.2024.2305899
Web of Science KeyUT	001148717900001
Related Url	isVersionOf https://doi.org/10.1080/0167482X.2024.2305899

Relevance of complement immunity with brain fog in patients with long COVID

FullText URL	fulltext20240304-02.pdf
Author	Hagiya, Hideharu\| Tokumasu, Kazuki\| Otsuka, Yuki\| Sunada, Naruhiko\| Nakano, Yasuhiro\| Honda, Hiroyuki\| Furukawa, Masanori\| Otsuka, Fumio\|
Keywords	Complement immunity Complement system Coronavirus disease 2019 Inflammation
Note	© 2023 Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases, and Japanese Society for Infection Prevention and Control. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/\| This fulltext file will be available in Feb. 2025.\|
Published Date	2024-03
Publication Title	Journal of Infection and Chemotherapy
Volume	volume30
Issue	issue3
Publisher	Elsevier
Start Page	236
End Page	241
ISSN	1341-321X
NCID	AA11057978
Content Type	Journal Article
language	English
OAI-PMH Set	岡山大学
Copyright Holders	© 2023 Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases, and Japanese Society for Infection Prevention and Control.
File Version	author
PubMed ID	37866620
DOI	10.1016/j.jiac.2023.10.016
Web of Science KeyUT	001167908700001
Related Url	isVersionOf https://doi.org/10.1016/j.jiac.2023.10.016

Characteristics of Persistent Symptoms Manifested after SARS-CoV-2 Vaccination: An Observational Retrospective Study in a Specialized Clinic for Vaccination-Related Adverse Events

FullText URL	fulltext.pdf
Author	Tokumasu, Kazuki\| Fujita-Yamashita, Manami\| Sunada, Naruhiko\| Sakurada, Yasue\| Yamamoto, Koichiro\| Nakano, Yasuhiro\| Matsuda, Yui\| Otsuka, Yuki\| Hasegawa, Toru\| Hagiya, Hideharu\| Honda, Hiroyuki\| Otsuka, Fumio\|
Keywords	adverse events COVID-19 SARS-CoV-2 vaccination mRNA vaccine
Published Date	2023-10-30
Publication Title	Vaccines
Volume	volume11
Issue	issue11
Publisher	MDPI
Start Page	1661
ISSN	2076-393X
Content Type	Journal Article
language	English
OAI-PMH Set	岡山大学
Copyright Holders	© 2023 by the authors.
File Version	publisher
PubMed ID	38005993
DOI	10.3390/vaccines11111661
Web of Science KeyUT	001113977600001
Related Url	isVersionOf https://doi.org/10.3390/vaccines11111661