Masahiro Tamura

Dr. Masahiro Tamura

orcid

Research Focus & Metrics

Academic Career Length

32Years (1995-Present)

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

Representative Publications

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28 August 2019 in Journal of Veterinary Internal Medicine
Verified
Journal Article
Open access
PDF file
MTMasahiro Tamura
Masahiro Tamura
HOHiroshi Ohta
Hiroshi Ohta
GSGenya Shimbo
Genya Shimbo
TOTatsuyuki Osuga
Tatsuyuki Osuga
NSNoboru Sasaki
Noboru Sasaki
MTMitsuyoshi Takiguchi
Mitsuyoshi Takiguchi
Background Two‐dimensional shear wave elastography (2D‐SWE) can noninvasively evaluate hepatic elastic modulus as shear wave velocity (SWV). Additionally, it may predict the presence of clinical relevant hepatic fibrosis (≥F2) in dogs with hepatic disease. Objectives To investigate whether SWV measured by 2D‐SWE can differentiate between dogs with (≥F2) and without (F0‐1) clinically relevant hepatic fibrosis. Animals Twenty‐eight client‐owned dogs with hepatic disease and 8 normal healthy Beagle dogs were enrolled. Methods In this cross‐sectional prospective study, SWVs were measured using 2D‐SWE in all dogs. Hepatic fibrosis stages and necroinflammatory activity grades were histopathologically evaluated using a histological scoring scheme that was adapted from the Ishak schema used in human medicine. Results Median SWVs were significantly higher in dogs with clinically relevant hepatic fibrosis (2.04 m/s; range, 1.81‐2.26 m/s) than in healthy dogs (1.51 m/s; range, 1.44‐1.66 m/s; P = .007), and dogs without clinically relevant hepatic fibrosis (1.56 m/s; range, 1.37‐1.67 m/s; P < .001). However, no significant difference was found in the SWVs between dogs without clinically relevant hepatic fibrosis and healthy dogs (P = .99). Furthermore, median SWVs were not significantly different among dogs with necroinflammatory activity, those without necroinflammatory activity, and healthy dogs (Kruskal‐Wallis test, P = .12). Conclusions and Clinical Importance The 2D‐SWE may be useful for predicting the presence of hepatic fibrosis in dogs with hepatic disease.

1 June 2019 in The Veterinary Journal
Verified
Journal Article
Closed access
RLR. Leela-Arporn
R. Leela-Arporn
HOHiroshi Ohta
Hiroshi Ohta
NNN. Nagata
N. Nagata
KSK. Sasaoka
K. Sasaoka
MTMasahiro Tamura
Masahiro Tamura
MTMitsuyoshi Takiguchi
Mitsuyoshi Takiguchi

1 January 1995 in Japanese Journal of Physical Fitness and Sports Medicine
Verified
Journal Article
Open access
Takashi AbeTakashi Abe
Takashi Abe
YTYoshimi Takiguchi
Yoshimi Takiguchi
MTMasahiro Tamura
Masahiro Tamura
JSJunko Shimura
Junko Shimura
KYKen-Ichi Yamazaki
Ken-Ichi Yamazaki

19 February 2019 in Journal of Veterinary Internal Medicine
Verified
Journal Article
Open access
PDF file
KNKhoirun Nisa
Khoirun Nisa
Sue Yee LimSue Yee Lim
Sue Yee Lim
MSMasayoshi Shinohara
Masayoshi Shinohara
TOTatsuyuki Osuga
Tatsuyuki Osuga
NYNozomu Yokoyama
Nozomu Yokoyama
MTMitsuyoshi Takiguchi
Mitsuyoshi Takiguchi
Background: Contrast-enhanced ultrasonography (CEUS) can be used to evaluate intestinal perfusion in healthy dogs. It is helpful for diagnosing and monitoring inflammatory bowel disease in humans and could be useful for dogs with chronic intestinal diseases. Objectives: To examine duodenal perfusion in dogs with chronic inflammatory enteropathy (CIE) and intestinal lymphoma. Animals: Client-owned dogs with CIE (n = 26) or intestinal lymphoma (n = 7) and dogs with gastrointestinal signs but histopathologically normal duodenum (controls, n = 14). Methods: In this cross-sectional study, dogs with CIE were classified into remission (n = 16) and symptomatic (n = 10) groups based on clinical scores determined at the time of CEUS. The duodenum was scanned after IV injection of Sonazoid® (0.01 mL/kg). CEUS-derived perfusion parameters, including time-to-peak, peak intensity (PI), area under the curve (AUC), and wash-in and wash-out rates were evaluated. Results: The PI was significantly higher in the symptomatic CIE group (median (range); 105.4 (89.3-128.8) MPV) than in the control group (89.9 (68.5-112.2) MPV). The AUC was significantly higher in the symptomatic CIE group (4847.9 (3824.3-8462.8) MPV.sec) than in the control (3448.9 (1559.5-4736.9) MPV.sec) and remission CIE (3862.3 (2094.5-6899.0) MPV.sec) groups. The PI and clinical score were positively correlated in the CIE group. No significant differences in perfusion parameters were detected between the lymphoma and CIE groups or the lymphoma and control groups. Conclusions and Clinical Importance: The PI and AUC can detect duodenal inflammation and hence are potentially useful for excluding a diagnosis of CIE.

1 January 2012 in Medical Mycology Journal
Verified
Journal Article
Open access
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NHNobuyoshi Hirose
Nobuyoshi Hirose
MTMasahiro Tamura
Masahiro Tamura
MSMorio Suganami
Morio Suganami
YOYumi Ogawa
Yumi Ogawa
MHMasataro Hiruma
Masataro Hiruma
Background : T. tonsurans infection is spreading among combat sport athletes in Japan, and preventive measures are necessary. Methods : A questionnaire survey and hairbrush-culture tests were conducted over a 4-year period on university judo athletes from about 50 university teams affiliated with the University Judo Federation of Tokyo. Culture-positive individuals were given specific treatment recommendations based on culture results and were advised to seek treatment at a medical clinic. Culture-positive individuals were re-tested at 3 months post-treatment. Results : Approximately 65% of participants reported a history of T. tonsurans infection. The incidence of hairbrush culture-positive individuals overall gradually decreased from 11.3% (academic year 2008) to 5.4% (2011). Each year the incoming freshmen had the highest infection rate of the four academic classes. Beginning in 2009 the infection rates decreased sharply among those who had participated in the survey the previous year, and the decreases continued the following year (s) until graduation. Among culture-positive individuals, the incidence of asymptomatic carriers increased each year, from 86% in 2008 to 98% in 2011. The culture-negative conversion rate was 86% overall for those undergoing treatment. Conclusion : Preventive measures against T. tonsurans infection in the University Judo Federation of Tokyo were successful in increasing awareness of the disease, lowering the incidence of infection, and detecting asymptomatic carriers who require treatment.

22 November 2023 in Cancers
Verified
Journal Article
Open access
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HYHiroki Yamazaki
Hiroki Yamazaki
SOSeio Onoyama
Seio Onoyama
SGShunichi Gotani
Shunichi Gotani
TDTatsuya Deguchi
Tatsuya Deguchi
MTMasahiro Tamura
Masahiro Tamura
HAHideo Akiyoshi
Hideo Akiyoshi
The transcription factor hypoxia-inducible factor 1α (HIF-1α) drives metabolic reprogramming in gliomas (GLs) under hypoxic conditions, promoting glycolysis for tumor development. Evofosfamide (EVO) releases a DNA-alkylating agent within hypoxic regions, indicating that it may serve as a hypoxia-targeted therapy. The aim of this study was to investigate the glycolytic metabolism and antitumor effects of EVO in a canine GL model. Our clinical data showed that overall survival was significantly decreased in GL dog patients with higher HIF-1α expression compared to that of those with lower HIF-1α expression, and there was a positive correlation between HIF-1α and pyruvate dehydrogenase kinase 1 (PDK1) expression, suggesting that glycolytic activity under hypoxia conditions may contribute to poor outcomes in canine GL. Our glycolysis assay tests showed that the glycolytic ATP level was higher than the mitochondrial ATP level in three types of canine GL cell lines by activating the HIF-1 signal pathway under hypoxia conditions, resulting in an overall increase in total cellular ATP production. However, treatment with EVO inhibited the glycolytic ATP level in the GL cell lines under hypoxia conditions by targeting HIF-1α-positive cells, leading to decrease in total cellular ATP production. Our in vivo tests showed that EVO significantly reduced tumor development compared to controls and temozolomide in murine GL models. A metabolic analysis demonstrated that EVO effectively suppressed glycolytic metabolism by eliminating HIF-1α-positive cells, suggesting that it may restore metabolism in canine GLs. The evidence presented here supports the favorable preclinical evaluation of EVO as a potential improvement in cancer metabolism.