Ryoichi Okamoto

1.9k total citations
72 papers, 1.6k citations indexed

About

Ryoichi Okamoto is a scholar working on Epidemiology, Hepatology and Molecular Medicine. According to data from OpenAlex, Ryoichi Okamoto has authored 72 papers receiving a total of 1.6k indexed citations (citations by other indexed papers that have themselves been cited), including 34 papers in Epidemiology, 28 papers in Hepatology and 23 papers in Molecular Medicine. Recurrent topics in Ryoichi Okamoto's work include Liver Disease Diagnosis and Treatment (23 papers), Antibiotic Resistance in Bacteria (23 papers) and Liver Diseases and Immunity (17 papers). Ryoichi Okamoto is often cited by papers focused on Liver Disease Diagnosis and Treatment (23 papers), Antibiotic Resistance in Bacteria (23 papers) and Liver Diseases and Immunity (17 papers). Ryoichi Okamoto collaborates with scholars based in Japan, United Kingdom and Indonesia. Ryoichi Okamoto's co-authors include Matsuhisa Inoue, Akio Kuga, Toyoji Okubo, Takashi Ida, Hisakazu Yano, Ryuichi Nakano, Toshimitsu Kobayashi, Kazuhide Yamamoto, Hidero Kitasato and Masato Nonoyama and has published in prestigious journals such as Hepatology, Journal of Clinical Microbiology and Antimicrobial Agents and Chemotherapy.

In The Last Decade

Ryoichi Okamoto

71 papers receiving 1.5k citations

Peers

Countries citing papers authored by Ryoichi Okamoto

Since Specialization

Citations

This map shows the geographic impact of Ryoichi Okamoto's research. It shows the number of citations coming from papers published by authors working in each country. You can also color the map by specialization and compare the number of citations received by Ryoichi Okamoto with the expected number of citations based on a country's size and research output (numbers larger than one mean the country cites Ryoichi Okamoto more than expected).

Fields of papers citing papers by Ryoichi Okamoto

Since Specialization

Physical SciencesHealth SciencesLife SciencesSocial Sciences

This network shows the impact of papers produced by Ryoichi Okamoto. Nodes represent research fields, and links connect fields that are likely to share authors. Colored nodes show fields that tend to cite the papers produced by Ryoichi Okamoto. The network helps show where Ryoichi Okamoto may publish in the future.

Co-authorship network of co-authors of Ryoichi Okamoto

This figure shows the co-authorship network connecting the top 25 collaborators of Ryoichi Okamoto. A scholar is included among the top collaborators of Ryoichi Okamoto based on the total number of citations received by their joint publications. Widths of edges represent the number of papers authors have co-authored together. Node borders signify the number of papers an author published with Ryoichi Okamoto. Ryoichi Okamoto is excluded from the visualization to improve readability, since they are connected to all nodes in the network.

All Works

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20 of 20 papers shown

#	Work	Indexed citations
1	Rapid assay for detecting gyrA and parC mutations associated with fluoroquinolone resistance in Enterobacteriaceae 2013 ·Journal of Microbiological Methods ·Ryuichi Nakano, Ryoichi Okamoto, Akiyo Nakano, Noriyuki Nagano, Michiko Abe, Shigeru Tansho‐Nagakawa, Tsuneyuki Ubagai, Takane Kikuchi‐Ueda, Osamu Koshio, Hirotoshi Kikuchi, Yasuo Ono	10
2	Influence of prior pandemic A(H1N1)2009 virus infection on invasion of MDCK cells by community-associated methicillin-resistant Staphylococcus aureus 2013 ·Journal of Infection and Chemotherapy ·Yoko Takayama, Hisakazu Yano, Yasuhiro Nojima, Ryuichi Nakano, Ryoichi Okamoto, Yoichi Hirakata, Keisuke Sunakawa, Tohru Akahoshi, Mitsuo Kaku	4
3	Prevalence and associated factors with esophageal varices in early primary biliary cirrhosis 2012 ·Journal of Gastroenterology and Hepatology ·Fusao Ikeda, Ryoichi Okamoto, Nobuyuki Baba, Shinichi Fujioka, (unknown), Kazuhisa Yabushita, Masaharu Ando, Shuji Matsumura, (unknown), Tetsuya Yasunaka, Yasuhiro Miyake, Yoshiaki Iwasaki, Haruhiko Kobashi, Hiroyuki Okada, Kazuhide Yamamoto	19
4	Definite Infective Endocarditis: Clinical and Microbiological Features of 155 Episodes in One Japanese University Hospital 2010 ·Journal of the Formosan Medical Association ·Yoko Takayama, Ryoichi Okamoto, Keisuke Sunakawa	19
5	A case of hepatocellular carcinoma with skin injury of the upper abdominal wall after transcatheter arterial chemoembolization: a case report 2009 ·Cases Journal ·(unknown), Kazuhiro Nouso, Koji Miyahara, (unknown), Sayo Kobayashi, Ichiro Sakakihara, (unknown), Shuji Uematsu, Ryoichi Okamoto, (unknown), Motowo Mizuno, Yasuyuki Araki	12
6	Clinical features of type 1 autoimmune hepatitis in adolescence and early adulthood 2009 ·Hepatology Research ·Yasuhiro Miyake, Yoshiaki Iwasaki, Haruhiko Kobashi, Tetsuya Yasunaka, Fusao Ikeda, Akinobu Takaki, Ryoichi Okamoto, Kouichi Takaguchi, Hiroshi Ikeda, Yasuhiro Makino, Kohsaku Sakaguchi, Masaharu Ando, Kazuhide Yamamoto	5
7	Clinical features of antinuclear antibodies‐negative type 1 autoimmune hepatitis 2008 ·Hepatology Research ·Yasuhiro Miyake, Yoshiaki Iwasaki, Haruhiko Kobashi, Tetsuya Yasunaka, Fusao Ikeda, Akinobu Takaki, Ryoichi Okamoto, Kouichi Takaguchi, Hiroshi Ikeda, Yasuhiro Makino, Masaharu Ando, Kohsaku Sakaguchi, Kazuhide Yamamoto	17
8	Clinical characteristics of fulminant‐type autoimmune hepatitis: an analysis of eleven cases 2006 ·Alimentary Pharmacology & Therapeutics ·Yasuhiro Miyake, Yudai Iwasaki, (unknown), Toru Onishi, Ryoichi Okamoto, Nobuyuki Sakai, Kohsaku Sakaguchi, Yasushi Shiratori	59
9	A case of HCC with erythrocytosis resulted in liver failure after hepatic resection 2005 ·Kanzo ·Hideki Aoki, Norihisa Takakura, Shigehiro Shiozaki, Ryoichi Okamoto, Yasuyuki Araki	2
10	Pretreatment of Pseudomonas aeruginosa with a sub-MIC of imipenem enhances bactericidal activity of neutrophils 2003 ·Journal of Infection and Chemotherapy ·(unknown), Yoshinori Sato, Tomoko Sekiguchi, (unknown), (unknown), Hidero Kitasato, Ryoichi Okamoto, Matsuhisa Inoue, Yoko Takayama, Ayako Sakamoto	5
11	A scoring system for primary biliary cirrhosis and its application for variant forms of autoimmune liver disease 2003 ·Journal of Gastroenterology ·Kazuhide Yamamoto, Ryo Terada, Ryoichi Okamoto, (unknown), Masanori Abe, Morikazu Onji, Takao Tsuji	27
12	In situ expression of Granzyme B and Fas‐ligand in the liver of viral hepatitis 2002 ·Liver International ·(unknown), Kazuhide Yamamoto, Kazuhisa Yabushita, Nobuaki Okano, Ryoichi Okamoto, Noriaki Shimada, Tomomi Hakoda, Motowo Mizuno, Toshihiro Higashi, Takao Tsuji	7
13	Laparoscopic Features of Primary Biliary Cirrhosis in AMA-Positive and AMA-Negative Patients 2002 ·Endoscopy ·Shin Fujioka, Kazuhiro Yamamoto, Ryoichi Okamoto, (unknown), (unknown), (unknown), (unknown), Yasuhiro Miyake, Hironori Nakajima, (unknown), (unknown), Masahito Tanimizu, Tetsuya Tsuji	5
14	Investigation of extended-spectrum β-lactamase in Klebsiellae pneumoniae and Escherichia coli from China 2002 ·Diagnostic Microbiology and Infectious Disease ·(unknown), Demei Zhu, Fu Wang, Yingyuan Zhang, Ryoichi Okamoto, Matsuhisa Inoue	51
15	Aberrant expression of cytokeratin 7 as a histological marker of progression in primary biliary cirrhosis 2001 ·Liver International ·Kazuhisa Yabushita, Kazuhide Yamamoto, (unknown), Nobuaki Okano, Shuji Matsumura, Ryoichi Okamoto, Noriaki Shimada, (unknown)	38
16	Expression of Perforin and Fas Ligand mRNA in the Liver of Viral Hepatitis 2000 ·Journal of Clinical Immunology ·(unknown), Kazuhide Yamamoto, Kozo Fujio, Takuya Nagano, Ryoichi Okamoto, (unknown), Kazuhisa Yabushita, Shuji Matsumura, Nobuaki Okano, (unknown)	11
17	Presence of Genes for .BETA.-Lactamases of Two Different Classes on a Single Plasmid from a Clinical Isolate of Serrtia marcescens. 1999 ·The Journal of Antibiotics ·Hisakazu Yano, Akio Kuga, (unknown), Ryoichi Okamoto, Toshimitsu Kobayashi, Matsuhisa Inoue	8
18	Activated liver macrophages in human liver diseases 1995 ·Journal of Gastroenterology and Hepatology ·Kazuhide Yamamoto, (unknown), Seiji Matsumoto, Takuya Nagano, Haruhiko Kobashi, Ryoichi Okamoto, Takao Tsuji	7
19	Antimicrobial activity of arbekacin, a new aminoglycoside antibiotic, against methicillin-resistant Staphylococcus aureus. 1994 ·PubMed ·Matsuhisa Inoue, Masato Nonoyama, Ryoichi Okamoto, Takashi Ida	31
20	Antibacterial activity of HBK 1986 ·Chemotherapy ·Ryoichi Okamoto, Susumu Mitsuhashi	6

Rankless uses publication and citation data sourced from OpenAlex, an open and comprehensive bibliographic database. While OpenAlex provides broad and valuable coverage of the global research landscape, it—like all bibliographic datasets—has inherent limitations. These include incomplete records, variations in author disambiguation, differences in journal indexing, and delays in data updates. As a result, some metrics and network relationships displayed in Rankless may not fully capture the entirety of a scholar's output or impact.

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