Ichiro Yamamoto

Dr. Ichiro Yamamoto


Research Focus & Metrics

Academic Career Length

33Years (1994-Present)

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

Representative Publications

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31 August 2012 in BMC Veterinary Research
Verified
Journal Article
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HTHiroshi Takemitsu
Hiroshi Takemitsu
DZDongwei Zhao
Dongwei Zhao
IYIchiro Yamamoto
Ichiro Yamamoto
YHYasuji Harada
Yasuji Harada
MMMasaki Michishita
Masaki Michishita
Toshiro AraiToshiro Arai
Toshiro Arai
Background: Bone marrow-derived mesenchymal stem cells (BM-MSCs) and adipose tissue-derived mesenchymal stem cells (AT-MSCs) are potential cellular sources of therapeutic stem cells. MSCs are a multipotent population of cells capable of differentiating into a number of mesodermal lineages. Treatment using MSCs appears to be a helpful approach for structural restoration in regenerative medicine. Correct identification of these cells is necessary, but there is inadequate information on the MSC profile of cell surface markers and mRNA expression in dogs. In this study, we performed molecular characterization of canine BM-MSCs and AT-MSCs using immunological and mRNA expression analysis. Results: Samples were confirmed to be multipotent based on their osteogenic and adipogenic differentiation. And these cells were checked as stem cell, hematopoietic and embryonic stem cell (ESC) markers by flow cytometry. BM- and AT-MSCs showed high expression of CD29 and CD44, moderate expression of CD90, and were negative for CD34, CD45, SSEA-3, SSEA-4, TRA-1-60, and TRA-1-81. SSEA-1 was expressed at very low levels in AT-MSCs. Quantitative real-time PCR (qRT-PCR) revealed expression of Oct3/4, Sox2, and Nanog in BM- and AT-MSCs. There was no significant difference in expression of Oct3/4 and Sox2 between BM-MSCs and AT-MSCs. However, Nanog expression was 2.5-fold higher in AT-MSCs than in BM-MSCs. Using immunocytochemical analysis, Oct3/4 and Sox2 proteins were observed in BM- and AT-MSCs. Conclusion: Our results provide fundamental information to enable for more reproducible and reliable quality control in the identification of canine BM-MSCs and AT-MSCs by protein and mRNA expression analysis.

13 August 2015 in BMC Veterinary Research
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Journal Article
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MFMegumi Fujiwara
Megumi Fujiwara
NMNobuko Mori
Nobuko Mori
TSTouko Sato
Touko Sato
HTHiroyuki Tazaki
Hiroyuki Tazaki
SIShingo Ishikawa
Shingo Ishikawa
Toshiro AraiToshiro Arai
Toshiro Arai
Obesity and overweight have been frequently observed in dogs and cats in recent years as in humans. The compositions of fatty acids (FAs) in the accumulated lipids in tissues of obese animals may have important roles in the process and mechanisms related to the onset of metabolic disorders. The purpose of this study was to evaluate the effects of a high fat (HF) diet, which contained a higher proportion of saturated FAs, on FA metabolism and distribution in obese cats. Cats (N = 12) were divided into control diet group (crude fat; 16.0 %) (n = 4) or a high fat (HF) diet group (crude fat; 23.9 %) (n = 8). The HF diet contained up to 60 % of calories from fat and was rich in stearic acid. Blood samples were collected at 0, 2, 4 and 6 weeks after the feeding. Adipose and liver tissues were collected at the 6th week after feeding. We performed analysis of histological findings and fatty acid composition in serum and tissues. Body weights of the cats significantly increased in the HF group. The increased activities of hepatic enzymes and the accumulation of lipid droplets were found in hepatocytes in the HF group at the 6th week after feeding. In this study, the stearic acid (C18:0)-rich HF diet contained less oleic acid (C18:1n-9) and more linoleic acid (C18:2n-6) than the control. However, the composition of oleic acid in the liver was higher, and those of stearic acid and linoleic acid were lower in the HF group at the 6th week after feeding. The higher oleic acid:stearic acid ratio suggests an increase in the conversion from saturated FA to mono-unsaturated FAs, which may reflect the hepatic storage of FAs as a relatively harmless form. The stearic acid-rich HF diet increased hepatic lipid accumulation accompanied by the increased of hepatic oleic acid, increased serum oleic acid and activation of hepatic enzymes. These findings could be an important sign of early stages of dyslipidemia and hepatic damage. Also, the higher oleic acid:stearic acid ratio might be related to the increased activity of SCD-1, which suggests that the stearic acid-rich HF diet evoked hepatic lipogenesis in the feline liver.

1 March 2020 in Medicine
Verified
Journal Article
Open access
MSMiho Sato
Miho Sato
MYMitsutake Yano
Mitsutake Yano
SSShimpei Sato
Shimpei Sato
YAYoko Aoyagi
Yoko Aoyagi
SASaki Aso
Saki Aso
KNKaei Nasu
Kaei Nasu
Rationale: The malignant potential and the appropriate treatment of uterine tumor resembling ovarian sex-cord tumor (UTROSCT) is controversial. Although these tumors generally have benign outcomes, several reports have described recurrences, metastases, and deaths associated with this disease. Patient concerns: A 57-year-old Japanese woman (gravida 2, para 2) was referred to our hospital for the evaluation and treatment of uterine fibroids. Magnetic resonance imaging revealed a right ovarian mass and multiple fibroids in the uterine myometrium. Diagnoses: The patient was diagnosed with UTROSCT with sarcomatous features. Interventions: She initially underwent a total abdominal hysterectomy and bilateral salpingo-oophorectomy, followed by second-stage surgery comprising pelvic and para-aortic lymphadenectomy and subtotal omentectomy. Outcomes: No postoperative recurrence was observed in the patient in 36 months. Lessons: In this case, extended radical surgery prevented the development of recurrent disease in a patient with UTROSCT with sarcomatous features. These clinicopathological findings suggest that UTROSCT is associated with several risk factors, including older age, presence of necrosis, lymphovascular invasion, significant nuclear atypia, and significant mitotic activity. This lesion type should be considered malignant and treated with curative intent.

27 September 2013 in BMC Veterinary Research
Verified
Journal Article
Open access
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SIShingo Ishikawa
Shingo Ishikawa
GLGebin Li
Gebin Li
HTHiroshi Takemitsu
Hiroshi Takemitsu
MFMegumi Fujiwara
Megumi Fujiwara
NMNobuko Mori
Nobuko Mori
Toshiro AraiToshiro Arai
Toshiro Arai
Background: Mammalian sirtuins are homologs to the yeast silent information regulator 2 (Sir2), which is an NAD-dependent deacetylase. Sirtuins are comprised of 7 proteins, and each has different target proteins. Sirtuin 1 (SIRT1) plays important roles in maintaining metabolic functions and immune responses, and SIRT3 protects cells from oxidative stress-induced cell death. Both SIRT1 and SIRT3 are regulated by metabolic status and aging. Hence, SIRT1 and SIRT3 have been researched in metabolic diseases, such as type 2 diabetes mellitus (DM), fatty liver, and heart diseases. Although these diseases have been increasing, there is little information about relation between the diseases and SIRT1 and SIRT3 in cats. Therefore we cloned SIRT1 and SIRT3 cDNA, examined mRNA expression in cat tissues, and investigated the changes in SIRT1 and SIRT3 mRNA expression in peripheral blood leukocyte of cats fed on HFD for 6 weeks. Results: Cat SIRT1 and SIRT3 contained a catalytic core region and showed high sequence homology with other vertebrate SIRT1 (>61.3%) and SIRT3 (>65.9%) amino acids. Real-time polymerase chain reaction analyses revealed that high expression levels were observed in the liver and skeletal muscle for SIRT1 and in the heart for SIRT3 in cats. In addition, both cat SIRT1 and SIRT3 expression levels in the pancreas were different between individuals. Cat SIRT1 mRNA expression in peripheral blood leukocytes was significantly elevated in obese cats fed on HFD (P < 0.05). Conclusions: Cat SIRT1 and SIRT3 genes are highly conserved among vertebrates, and HFD feeding may be related to SIRT1 mRNA expression mechanisms in cat peripheral blood leukocytes.

14 March 2014 in BMC Veterinary Research
Verified
Journal Article
Open access
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GLGebin Li
Gebin Li
浩川浩 川角
浩 川角
YOYuki Okada
Yuki Okada
SIShingo Ishikawa
Shingo Ishikawa
IYIchiro Yamamoto
Ichiro Yamamoto
NMNobuko Mori
Nobuko Mori
The aim of this study is to compare metabolic parameters, malondialdehyde as a lipid oxidation marker, and lipid profiles between dogs with untreated hyperlipidemia and hyperlipidemia with treatment, in order to examine the usefulness of malondialdehyde and lipid profiles as diagnostic parameters at early stages of hyperlipidemia. Dog samples were collected from four different veterinary clinics across Japan from March to June 2013. They were separated into three groups: control, untreated hyperlipidemia based on temporally screening, and hyperlipidemia with current anti-hyperlipidemic (statins and fibrates) treatment. Triglyceride levels of untreated hyperlipidemia dogs were significantly higher than those of control dogs. ALT levels of hyperlipidemic dogs with treatment were the highest among three groups. VLDL and LDL of both cholesterol and triglyceride of untreated hyperlipidemia dogs were the highest among three groups. HDL1 levels in triglyceride of hyperlipidemia dogs with treatment were significantly higher than those of control and untreated hyperlipidemia dog. Malondialdehyde concentrations of untreated hyperlipidemia dogs were significantly higher than those of control and hyperlipidemic dogs with treatment. In this study, dogs with untreated hyperlipidemia clearly showed abnormal lipid status, whereas hyperlipidemic dogs under anti-hyperlipidemia treatment showed more normal lipid status suggesting the effectiveness of the therapy. Anti-hyperlipidemics (statins and fibrates) for dogs are also effective in relieving elevated levels of lipids and lipid oxidation. Plasma lipid (triglyceride and cholesterol) profiles and malondialdehyde are useful diagnostic tools for identifying early stages of untreatment hyperlipidemia in dogs.

15 September 2020 in Veterinary Medicine and Science
Verified
Journal Article
Open access
PDF file
IYIchiro Yamamoto
Ichiro Yamamoto
KKKoh Kawasumi
Koh Kawasumi
KOKozo Ohkusu‐Tsukada
Kozo Ohkusu‐Tsukada
Toshiro AraiToshiro Arai
Toshiro Arai
G protein‐coupled receptors 41 and 43 were identified and characterized as free fatty acid receptors (FFAR) 3 and 2, respectively. FFAR2 and FFAR3 mediate short‐chain fatty acids (SCFAs) as signalling molecules. The present study aimed to give molecular characterization of FFAR2 and FFAR3 in the domestic cat. High homology with that in other mammals was revealed by cDNA cloning of cat FFAR2 FFAR3. We analyzed the tissue distribution of cat FFAR2 and FFAR3 mRNA using quantitative polymerase chain reaction. The inhibition of intracellular cAMP concentrations was observed in cells transfected with cat FFAR2 or FFAR3 and treated with SCFAs. The activation of nuclear factor of activated T cells‐luciferase reporter was only observed in cat FFAR2 transfected cells but not in FFAR3. Split luciferase assay (NanoLuc Binary Technology; NanoBiT) for FFAR2 or FFAR3 and Arrestin‐3/β‐arrestin‐2 revealed acetate‐/propionate‐induced recruitment to cat FFAR2 or FFAR3 in CHO‐K1 cells. Our results indicate that FFAR2 and FFAR3 are functional receptor proteins that are expressed in cat tissues and show differential distribution patterns.