Atsushi Yamamoto

Dr. Atsushi Yamamoto

orcid

Research Focus & Metrics

Academic Career Length

27Years (2000-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 May 2014 in Journal of Shoulder and Elbow Surgery
Verified
Journal Article
Closed access
TKTsutomu Kobayashi
Tsutomu Kobayashi
KTKenji Takagishi
Kenji Takagishi
Hitoshi ShitaraHitoshi Shitara
Hitoshi Shitara
TITsuyoshi Ichinose
Tsuyoshi Ichinose
DSDaisuke Shimoyama
Daisuke Shimoyama
TTTsuyoshi Tajika
Tsuyoshi Tajika

Verified
Journal Article
Open access
PDF file
TKTakaomi Kessoku
Takaomi Kessoku
TKTakashi Kobayashi
Takashi Kobayashi
KTKosuke Tanaka
Kosuke Tanaka
AYAtsushi Yamamoto
Atsushi Yamamoto
KTKota Takahashi
Kota Takahashi
Atsushi  NakajimaAtsushi Nakajima
Atsushi Nakajima
The liver directly accepts blood from the gut and is, therefore, exposed to intestinal bacteria. Recent studies have demonstrated a relationship between gut bacteria and nonalcoholic fatty liver disease (NAFLD). Approximately 10–20% of NAFLD patients develop nonalcoholic steatohepatitis (NASH), and endotoxins produced by Gram-negative bacilli may be involved in NAFLD pathogenesis. NAFLD hyperendotoxicemia has intestinal and hepatic factors. The intestinal factors include impaired intestinal barrier function (leaky gut syndrome) and dysbiosis due to increased abundance of ethanol-producing bacteria, which can change endogenous alcohol concentrations. The hepatic factors include hyperleptinemia, which is associated with an excessive response to endotoxins, leading to intrahepatic inflammation and fibrosis. Clinically, the relationship between gut bacteria and NAFLD has been targeted in some randomized controlled trials of probiotics and other agents, but the results have been inconsistent. A recent randomized, placebo-controlled study explored the utility of lubiprostone, a treatment for constipation, in restoring intestinal barrier function and improving the outcomes of NAFLD patients, marking a new phase in the development of novel therapies targeting the intestinal barrier. This review summarizes recent data from studies in animal models and randomized clinical trials on the role of the gut–liver axis in NAFLD pathogenesis and progression.

26 May 2022 in Clinical and Translational Gastroenterology
Verified
Journal Article
Open access
YKYuki Kasai
Yuki Kasai
TKTakaomi Kessoku
Takaomi Kessoku
KTKosuke Tanaka
Kosuke Tanaka
AYAtsushi Yamamoto
Atsushi Yamamoto
KTKota Takahashi
Kota Takahashi
Atsushi  NakajimaAtsushi Nakajima
Atsushi Nakajima
INTRODUCTION: No reports on both blood and fecal bile acids (BAs) in patients with nonalcoholic fatty liver disease (NAFLD) exist. We simultaneously assessed the serum and fecal BA patterns in healthy participants and those with NAFLD. METHODS: We collected stool samples from 287 participants from 5 hospitals in Japan (healthy control [HC]: n = 88; mild fibrosis: n = 104; and advanced fibrosis group: n = 95). Blood samples were collected and analyzed for serum BAs and 7α-hydroxy-4-cholesten-3-one (C4)—a surrogate marker for BA synthesis ability—from 141 patients. Concentrations of BAs, including cholic acid (CA), deoxycholic acid (DCA), chenodeoxycholic acid, ursodeoxycholic acid, and lithocholic acid (LCA), were measured using liquid chromatography-mass spectrometry. RESULTS: The total fecal BA concentration was significantly higher in the NAFLD group with worsening of fibrosis than in the HC group. Most of the fecal BAs were secondary and unconjugated. In the fecal BA fraction, CA, DCA, chenodeoxycholic acid, ursodeoxycholic acid, and LCA were significantly higher in the NAFLD than in the HC group. The total serum BA concentration was higher in the NAFLD group with worsening of fibrosis than in the HC group. In the serum BA fraction, CA, LCA, and C4 concentrations were significantly higher in the NAFLD than in the HC group. DISCUSSION: Fecal and serum BA and C4 concentrations were high in patients with NAFLD with worsening of fibrosis, suggesting involvement of abnormal BA metabolism in NAFLD with fibrosis progression. Abnormalities in BA metabolism may be a therapeutic target in NAFLD with fibrosis.

24 April 2022 in Cancers
Verified
Journal Article
Open access
PDF file
AOAnna Ozaki
Anna Ozaki
TKTakaomi Kessoku
Takaomi Kessoku
KTKosuke Tanaka
Kosuke Tanaka
AYAtsushi Yamamoto
Atsushi Yamamoto
KTKota Takahashi
Kota Takahashi
Atsushi  NakajimaAtsushi Nakajima
Atsushi Nakajima
Opioid-induced constipation (OIC) may occur in patients receiving opioid treatment, decreasing their quality of life (QOL). We compared the effectiveness of magnesium oxide (MgO) with that of naldemedine (NAL) in preventing OIC. This proof-of-concept, randomized controlled trial (registration number UMIN000031891) involved 120 patients with cancer scheduled to receive opioid therapy. The patients were randomly assigned and stratified by age and sex to receive MgO (500 mg, thrice daily) or NAL (0.2 mg, once daily) for 12 weeks. The change in the average Japanese version of Patient Assessment of Constipation QOL (JPAC-QOL) from baseline to 2 weeks was assessed as the primary endpoint. The other endpoints were spontaneous bowel movements (SBMs) and complete SBMs (CSBMs). Deterioration in the mean JPAC-QOL was significantly lower in the NAL group than in the MgO group after 2 weeks. There were fewer adverse events in the NAL group than in the MgO group. Neither significant differences in the change in SBMs between the groups nor serious adverse events/deaths were observed. The CSBM rate was higher in the NAL group than in the MgO group at 2 and 12 weeks. In conclusion, NAL significantly prevented deterioration in constipation-specific QOL and CSBM rate compared with MgO.

1 January 2001 in Fish Pathology
Verified
Journal Article
Open access
AYAtsushi Yamamoto
Atsushi Yamamoto
STShinnosuke Toyomura
Shinnosuke Toyomura
MSMineo Saneyoshi
Mineo Saneyoshi
KHKishio Hatai
Kishio Hatai

31 December 2017 in Asian Spine Journal
Verified
Journal Article
Open access
PDF file
TKTakanori Kitagawa
Takanori Kitagawa
YIYoichi Iizuka
Yoichi Iizuka
HKHiroki Kobayashi
Hiroki Kobayashi
TMTokue Mieda
Tokue Mieda
DTDaisuke Tsunoda
Daisuke Tsunoda
KTKenji Takagishi
Kenji Takagishi
Study DesignCross-sectional study.PurposeThe purpose of this study was to evaluate the correlation between pelvic tilt (PT) and the sacro-femoral-pubic (SFP) angle, which is easier to identify than PT, in middle-aged and elderly Asian subjects from the general population.Overview of LiteratureMeasuring PT is important in the diagnosis and treatment of adult spinal deformity. However, identifying femoral heads, which are necessary to determine PT, using sagittal radiographs is often difficult.MethodsStanding coronal and sagittal pelvic radiographs of individuals aged more than 50 years were taken during a local medical examination. The subjects were divided into female, male, and total groups at the time of evaluation. Linear regression analysis was performed to investigate the relationship between PT and the SFP angle, which were obtained from the X-rays.ResultsThe present study included 291 subjects. There were no statistically significant differences between the left and right SFP angles, and there was gender difference regarding the SFP angle. However, a gender difference was observed regarding PT. The correlation between PT and the SFP angle was substantiated in each group. Pearson's correlation coefficients between PT and the SFP angle in the total, female, and male groups were 0.696, 0.853, and 0.619, respectively. In the linear regression analysis, PT was calculated as follows: PT=60.1−0.77×(SFP angle) in the total group, PT=62.8−0.80×(SFP angle) in the female group, and PT=51.5−0.64×(SFP angle) in the male group.ConclusionsA significant correlation between PT and the SFP angle was observed in middle-aged and elderly Asian subjects from the general population.