78 results on '"Akihiro Yamauchi"'
Search Results
2. Mechanochemically Prepared Li2S–P2S5–LiBH4 Solid Electrolytes with an Argyrodite Structure
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Atsushi Sakuda, Akihiro Yamauchi, So Yubuchi, Naoto Kitamura, Yasushi Idemoto, Akitoshi Hayashi, and Masahiro Tatsumisago
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Chemistry ,QD1-999 - Published
- 2018
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3. Placental extract suppresses cardiac hypertrophy and fibrosis in an angiotensin II-induced cachexia model in mice
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Akihiro Yamauchi, Akiko Kamiyoshi, Takayuki Sakurai, Hiroyuki Miyazaki, Eiichi Hirano, Hong Seok Lim, Taiichi Kaku, and Takayuki Shindo
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Biochemistry ,Cardiac hypertrophy ,Human placenta extract ,Cardiac fibrosis ,Angiotensin II ,Cachexia ,Science (General) ,Q1-390 ,Social sciences (General) ,H1-99 - Abstract
Cachexia is an intractable metabolic disorder that causes extreme weight loss. It is a symptom of many chronic diseases, including cancer, liver failure, congestive heart failure and chronic kidney disease, and there is as yet no effective treatment. While the mechanisms underlying cachexia are complex, it is often accompanied by elevated angiotensin II (Ang II). Human placental extract (HPE) is a source of numerous biologically active molecules and has been used clinically to treat chronic hepatitis, liver cirrhosis and other chronic diseases. Here, we investigated the effects of HPE in an Ang II-induced cachexia model in mice. HPE treatment preserved both fat mass and lean body mass and suppressed weight loss in the cachexia model, though food intake was unaffected. Ang II infusion also caused cardiac hypertrophy and fibrosis. HPE suppressed these effects as well as Ang II-induced cardiac expression of genes related to heart failure and cardiac remodeling. HPE also reversed Ang II-induced downregulation of mitochondria-related molecules and suppressed cardiac inflammation and oxidative stress. HPE administration may thus be an effective approach to the treatment of cachexia, cardiac hypertrophy and fibrosis.
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- 2019
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4. Development of a mouse iron overload-induced liver injury model and evaluation of the beneficial effects of placenta extract on iron metabolism
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Akihiro Yamauchi, Akiko Kamiyoshi, Takayuki Sakurai, Hiroyuki Miyazaki, Eiichi Hirano, Hong-Seok Lim, Taiichi Kaku, and Takayuki Shindo
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Molecular biology ,Science (General) ,Q1-390 ,Social sciences (General) ,H1-99 - Abstract
Hepatic iron deposition is seen in cases of chronic hepatitis and cirrhosis, and is a hallmark of a poorer prognosis. Iron deposition is also found in non-alcoholic steatohepatitis (NASH) patients. We have now developed a mouse model of NASH with hepatic iron deposition by combining a methione- and choline-deficient (MCD) diet with an iron-overload diet. Using this model, we evaluated the effects of human placenta extract (HPE), which has been shown to ameliorate the pathology of NASH. Four-week-old male C57BL/6 mice were fed the MCD diet with 2% iron for 12 weeks. In liver sections, iron deposition was first detected around the portal vein after 1 week. From there it spread throughout the parenchyma. Biliary iron concentrations were continuously elevated throughout the entire 12-week diet. As a compensatory response, the diet caused elevation of serum hepcidin, which accelerates excretion of iron from the body. Accumulation of F4/80-positive macrophages was detected within the sinusoids from the first week onward, and real-time PCR analysis revealed elevated hepatic expression of genes related inflammation and oxidative stress. In the model mice, HPE treatment led to a marked reduction of hepatic iron deposition with a corresponding increase in biliary iron excretion. Macrophage accumulation was much reduced by HPE treatment, as was the serum oxidation-reduction potential, an index of oxidative stress. These data indicate that by suppressing inflammation, oxidative stress and iron deposition, and enhancing iron excretion, HPE effectively ameliorates iron overload-induced liver injury. HPE administration may thus be an effective strategy for treating NASH.
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- 2019
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5. Awake craniotomy for the sensorimotor tumors : combined use of synthesized surface anatomy scanning, stimulation cortical mapping and frameless neuronavigation system
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Fumihiro Imai, Junpei Shibata, Minoru Yoneda, Akihiro Yamauchi, Atsuhiro Kuno, Haruna Imai, Jumpei Oda, Tatsuo Omi, Motoki Oeda, Takeya Suzuki, Riki Tanaka, Hirotaka Kogame, Shingo Maeda, Kei Yamashiro, and Yuichi Hirose
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awake craniotomy ,functional brain mapping ,neuronavigation system ,eloquent area ,brain neoplasm ,Medicine (General) ,R5-920 - Abstract
Objectives: Functional brain mapping and precise localization are essential for the resection of centrally located tumors. We describe our initial experience with awake craniotomy for sensorimotor tumors in 15 patients using synthesized surface anatomy scanning (SSAS), intraoperative functional brain mapping, and an infrared-based navigation system (INS) without fixation of the patient’s head. Methods: Craniotomy positioning was planned using the images created by SSAS. Fiducial markers were placed along the skin incision line for intraoperative registration of an INS. The resection of the tumor was performed under local anesthesia using both intraoperative functional brain mapping and an INS. In or near the motor cortex or the descending motor pathway, the extent of the resection was determined by the stimulation induced motor response and the intraoperative neurologic findings. Results: Appropriately centered craniotomies were obtained in all cases using the presurgical planning images of SSAS. Reliable functional localization was identified with direct cortical and subcortical stimulation. The location of the tumors was detected within 3.5 mm of that predicted by the computation (target registration error). Postoperative computed tomography scans showed grossly total resection of the tumor in 13 of 15 cases and subtotal resection in 2 cases. Although 10 patients had mild to severe neurologic deficits in the immediate postoperative period, there were no permanent deficits. Conclusions: Sensorimotor tumors can be resected effectively with the combined use of SSAS, stimulation cortical mapping and an INS with clinical acceptable morbidity.
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- 2016
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6. Placental extract ameliorates non-alcoholic steatohepatitis (NASH) by exerting protective effects on endothelial cells
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Akihiro Yamauchi, Akiko Kamiyoshi, Teruhide Koyama, Nobuyoshi Iinuma, Shumpei Yamaguchi, Hiroyuki Miyazaki, Eiichi Hirano, Taiichi Kaku, and Takayuki Shindo
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Health Sciences ,Metabolism ,Pathology ,Pharmaceutical science ,Science (General) ,Q1-390 ,Social sciences (General) ,H1-99 - Abstract
Non-alcoholic steatohepatitis (NASH) is a severe form of fatty liver disease that is defined by the presence of inflammation and fibrosis, ultimately leading to cirrhosis and hepatocellular carcinoma. Treatment with human placental extract (HPE) reportedly ameliorates the hepatic injury. We evaluated the effect of HPE treatment in a mouse model of NASH. In the methione- and choline-deficient (MCD) diet-induced liver injury model, fibrosis started from regions adjacent to the sinusoids. We administered the MCD diet with high-salt loading (8% NaCl in the drinking water) to mice deficient in the vasoprotective molecule RAMP2 for 5 weeks, with or without HPE. In both the HPE and control groups, fibrosis was seen in regions adjacent to the sinusoids, but the fibrosis was less pronounced in the HPE-treated mice. Levels of TNF-α and MMP9 expression were also significantly reduced in HPE-treated mice, and oxidative stress was suppressed in the perivascular region. In addition, HPE dose-dependently increased survival of cultured endothelial cells exposed to 100 μM H2O2, and it upregulated expression of eNOS and the anti-apoptotic factors bcl-2 and bcl-xL. From these observations, we conclude that HPE ameliorates NASH-associated pathologies by suppressing inflammation, oxidative stress and fibrosis. These beneficially effects of HPE are in part attributable to its protective effects on liver sinusoidal endothelial cells. HPE could thus be an attractive therapeutic candidate with which to suppress progression from simple fatty liver to NASH.
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- 2017
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7. Retrospective analysis of large bowel obstruction or perforation caused by oral preparation for colonoscopy
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Akihiro Yamauchi, Shin-ei Kudo, Yuichi Mori, Hideyuki Miyachi, Masashi Misawa, Hatsumi Kamo, Tomokazu Hisayuki, Toyoki Kudo, Takemasa Hayashi, Kunihiko Wakamura, Atsushi Katagiri, Toshiyuki Baba, Eiji Hidaka, and Fumio Ishida
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Diseases of the digestive system. Gastroenterology ,RC799-869 - Abstract
Background and study aims Patients undergoing bowel preparation for colonoscopy are at risk of potentially severe adverse events such as large-bowel obstruction (LBO) and perforation. These patients usually need emergency surgery and the consequences may be fatal. Little is known about the risk factors for LBO and perforation in these circumstances. We sought to establish the natural history of LBO and perforation caused by oral preparation for colonoscopy. Patients and methods We retrospectively analyzed data from 20 patients with LBO or perforation associated with oral preparation for colonoscopy. All patients were treated at the Showa University Northern Yokohama Hospital (SUNYH) between April 2001 and December 2015. Drugs used for bowel preparation, age, sex, indication for colonoscopy, pathogenesis and treatment were recorded. Results Eighteen of the patients had LBO and 2 had perforation. Fourteen events occurred at SUNYH, which accounted for 0.016 % of patients who underwent bowel preparation during this period. Seventeen patients were symptomatic when the decision to undertake colonoscopy was made (including 7 who complained of constipation and 4 who complained of abdominal pain; 3e were asymptomatic). Nineteen patients ultimately required surgery, 13 within 3 days of presentation. Eleven patients ultimately required colostomy. There was no perioperative mortality in our cases. Conclusion Large bowel obstruction and perforation are rare events associated with oral preparation for colonoscopy, but frequently require surgery. Exacerbation of constipation might be a risk factor for LBO or perforation. Potentially catastrophic situations can be avoided by early detection and treatment.
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- 2017
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8. Adrenomedullin-RAMP2 system suppresses ER stress-induced tubule cell death and is involved in kidney protection.
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Ryuichi Uetake, Takayuki Sakurai, Akiko Kamiyoshi, Yuka Ichikawa-Shindo, Hisaka Kawate, Yasuhiro Iesato, Takahiro Yoshizawa, Teruhide Koyama, Lei Yang, Yuichi Toriyama, Akihiro Yamauchi, Kyoko Igarashi, Megumu Tanaka, Takashige Kuwabara, Kiyoshi Mori, Motoko Yanagita, Masashi Mukoyama, and Takayuki Shindo
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Medicine ,Science - Abstract
Various bioactive peptides have been implicated in the homeostasis of organs and tissues. Adrenomedullin (AM) is a peptide with various bioactivities. AM-receptor, calcitonin-receptor-like receptor (CLR) associates with one of the subtypes of the accessory proteins, RAMPs. Among the RAMP subisoforms, only RAMP2 knockout mice ⁻/⁻ reproduce the phenotype of embryonic lethality of AM⁻/⁻, illustrating the importance of the AM-RAMP2-signaling system. Although AM and RAMP2 are abundantly expressed in kidney, their function there remains largely unknown. We used genetically modified mice to assess the pathophysiological functions of the AM-RAMP2 system. RAMP2⁺/⁻ mice and their wild-type littermates were used in a streptozotocin (STZ)-induced renal injury model. The effect of STZ on glomeruli did not differ between the 2 types of mice. On the other hand, damage to the proximal urinary tubules was greater in RAMP2⁺/⁻. Tubular injury in RAMP2⁺/⁻ was resistant to correction of blood glucose by insulin administration. We examined the effect of STZ on human renal proximal tubule epithelial cells (RPTECs), which express glucose transporter 2 (GLUT2), the glucose transporter that specifically takes up STZ. STZ activated the endoplasmic reticulum (ER) stress sensor protein kinase RNA-like endoplasmic reticulum kinase (PERK). AM suppressed PERK activation, its downstream signaling, and CCAAT/enhancer-binding homologous protein (CHOP)-induced cell death. We confirmed that the tubular damage was caused by ER stress-induced cell death using tunicamycin (TUN), which directly evokes ER stress. In RAMP2⁺/⁻ kidneys, TUN caused severe injury with enhanced ER stress. In wild-type mice, TUN-induced tubular damage was reversed by AM administration. On the other hand, in RAMP2⁺/⁻, the rescue effect of exogenous AM was lost. These results indicate that the AM-RAMP2 system suppresses ER stress-induced tubule cell death, thereby exerting a protective effect on kidney. The AM-RAMP2 system thus has the potential to serve as a therapeutic target in kidney disease.
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- 2014
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9. At-Sea Habitat Use of Rhinoceros Auklets Breeding in the Shelf Region of Eastern Hokkaido
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Takahiro Sato, Yuki Yabuhara, Jumpei Okado, Yutaka Watanuki, Akihiro Yamauchi, and Yoichi Kawaguchi
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Birds ,Charadriiformes ,GPS logger ,Chlorophyll A ,marine habitat ,Cerorhinca monocerata ,conservation ,Animals ,Animal Science and Zoology ,movement ,Ecosystem ,Perissodactyla - Abstract
At-sea habitat use of breeding seabirds is strongly influenced by marine environmental features that vary over space and time. The use of bio-loggers allows researchers to track fine-scale movements of seabirds and provides opportunities to identify the primary factors affecting their area use for foraging. Using GPS loggers, we tracked chick-rearing rhinoceros auklets (Cerorhinca monocerata), which are wing-propelled divers, at Daikoku Island, eastern Hokkaido, Japan. The central phase for foraging activity on birds' trips was determined using a multiple change points model. To examine environmental factors explaining the distribution of the foraging phase, a generalized additive model was used where sea surface temperature, chlorophyll a concentration, bathymetry, and distance from the colony were explanatory variables. To obtain information supporting the behavioral tracking, prey items in the bill-loads of adult auklets were collected. We found that auklets foraged over the continental shelf shallower than the 200-m isobath and that distance from the colony was related to the area use. Adult auklets predominately brought back age-0 chum salmon (Oncorhynchus keta), which was abundant in coastal waters along southeast Hokkaido during the study period. Our findings indicate that rhinoceros auklets rearing chicks, hence visiting nests frequently, on Daikoku Island can find suitable feeding grounds nearby.
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- 2022
10. Study on the relationship between fuel fragmentation during a LOCA and pellet microstructure
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Akihiro Yamauchi
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Nuclear and High Energy Physics ,Materials science ,Nuclear Energy and Engineering ,Nuclear engineering ,Pellet ,Fragmentation (computing) ,Microstructure - Abstract
To systematically examine the relationship between the fuel fragmentation during a loss-of-coolant accident (LOCA) and the pellet microstructure, heating tests were conducted on micro fuel samples ...
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- 2021
11. Study on the condition for ductile-brittle transition of cladding tube at high temperature
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Akihiro Yamauchi
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Nuclear Energy and Engineering - Published
- 2021
12. A study on macroscopic fuel cladding ductile-to-brittle transition at 300°C induced by radial hydrides
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Keizo Ogata and Akihiro Yamauchi
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Burst test ,Nuclear and High Energy Physics ,Brittleness ,Materials science ,Nuclear Energy and Engineering ,Precipitation (chemistry) ,Hydride ,Zirconium alloy ,Composite material ,Cladding (fiber optics) - Abstract
In this paper, to clarify the conditions for the occurrence of macroscopic hydrogen-induced ductile-to-brittle transitions (DBT) at operational temperatures, the effect of hydride precipitation on ...
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- 2019
13. Regulation of cardiovascular development and homeostasis by the adrenomedullin-RAMP system
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Megumu Tanaka, Akiko Kamiyoshi, Takayuki Sakurai, Akihiro Yamauchi, Yuka Ichikawa-Shindo, Takayuki Shindo, and Hisaka Kawate
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medicine.medical_specialty ,Physiology ,030209 endocrinology & metabolism ,Calcitonin gene-related peptide ,Receptor Activity-Modifying Protein 2 ,Receptor Activity-Modifying Protein 3 ,Biochemistry ,Receptor Activity-Modifying Proteins ,Adrenomedullin ,Mice ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,0302 clinical medicine ,Endocrinology ,Internal medicine ,Animals ,Homeostasis ,Medicine ,Receptor ,Mice, Knockout ,business.industry ,Lymphatic system ,RAMP2 ,Calcitonin ,Circulatory system ,Knockout mouse ,business ,030217 neurology & neurosurgery - Abstract
Adrenomedullin (AM), a member of the calcitonin peptide superfamily, is a peptide involved in both the pathogenesis of cardiovascular diseases and circulatory homeostasis. Its receptor, calcitonin receptor-like receptor (CLR), associates with an accessory protein, receptor activity-modifying protein (RAMP). Depending upon which the three RAMP isoforms (RAMP1-3) it interacts with, CLR functions as a receptor for AM or other calcitonin family peptides. AM knockout mice (-/-) died mid-gestation due to abnormalities in vascular development. We found that phenotypes similar to AM-/- were reproduced only in RAMP2-/- mice. We generated endothelial cell-specific RAMP2 knockout mice (E-RAMP2-/-) and found most E-RAMP2-/- mice died perinatally. In surviving adults, vasculitis and organ fibrosis occurred spontaneously. We next generated drug-inducible cardiac myocyte-specific RAMP2-/- (DI-C-RAMP2-/-) mice, which exhibited dilated cardiomyopathy-like heart failure with cardiac dilatation and myofibril disruption. DI-C-RAMP2-/- hearts also showed changes in mitochondrial structure and downregulation of mitochondria-related genes involved in oxidative phosphorylation and β-oxidation. In contrast to RAMP2-/- mice, RAMP3-/- mice were born with no major abnormalities. In adult RAMP3-/- mice, postnatal angiogenesis was normal, but drainage of subcutaneous lymphatic vessels was delayed. RAMP3-/- mice also showed more severe interstitial edema than in wild-type mice in a tail lymphedema model. These findings show that the AM-RAMP system is a key determinant of cardiovascular integrity and homeostasis from prenatal stages through adulthood. The AM-RAMP2 system mainly regulates vascular development and homeostasis, while the AM-RAMP3 system mainly regulates lymphatic function in adults. The AM-RAMP system may thus have therapeutic potential for the treatment of cardiovascular diseases.
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- 2019
14. RAMP3 deficiency enhances postmenopausal obesity and metabolic disorders
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Masaaki Tanaka, Kun Dai, Kazutaka Hirabayashi, Akihiro Yamauchi, Keisei Nakamura, Teng Liu, Takayuki Sakurai, Akiko Kamiyoshi, Takayuki Shindo, Nanqi Cui, Shuhei Matsui, Yangxuan Wei, Hisaka Kawate, Yuka Ichikawa-Shindo, Shiho Iida, and Megumu Tanaka
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0301 basic medicine ,medicine.medical_specialty ,Physiology ,medicine.drug_class ,Ovariectomy ,Estrogen receptor ,Adipose tissue ,Diet, High-Fat ,Real-Time Polymerase Chain Reaction ,Receptor Activity-Modifying Protein 3 ,Biochemistry ,Mice ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,Endocrinology ,Insulin resistance ,Internal medicine ,medicine ,Animals ,Obesity ,Receptor ,Mice, Knockout ,business.industry ,Body Weight ,Glucose Tolerance Test ,medicine.disease ,Rats ,Mice, Inbred C57BL ,Postmenopause ,Adrenomedullin ,030104 developmental biology ,Adipose Tissue ,Estrogen ,Female ,Steatosis ,business ,GPER ,hormones, hormone substitutes, and hormone antagonists - Abstract
There is a marked increase in the incidence of visceral adiposity and insulin resistance among women following menopause. Adrenomedullin (AM) is an endogenous peptide first identified as a vasodilator, but now known to exert a variety of physiological effects. RAMP3 is a receptor activity-modifying protein that binds to the AM receptor (calcitonin receptor-like receptor). As expression of both AM and RAMP3 is reportedly activated by estrogen, we hypothesized that RAMP3 is crucially involved in the pathophysiology of postmenopausal obesity. To test this idea, we compared the effects of ovariectomy (OVX) and a high-fat diet for 10 weeks (a model of postmenopausal obesity) between RAMP3 knockout (RAMP3-/-) and wild-type mice. RAMP3-/- OVX mice exhibited greater obesity and adipose tissue weight gain as compared to wild-type OVX mice. RAMP3-/- OVX mice also exhibited higher serum insulin levels. In periuterine WAT from RAMP3-/- OVX mice, expression of lipolysis-related factors was lower and expression of inflammation-related factors was higher than in wild-type OVX mice. Hepatic steatosis was also exacerbated in RAMP3-/- OVX. Notably, expression of the membrane-type estrogen receptor GPR30 was downregulated in periuterine WAT from RAMP3-/- OVX mice. These findings raise the possibility that a GPR30-RAMP3 interaction is involved in the pathophysiology of postmenopausal obesity and suggest RAMP3 plays a key role in the regulation of energy metabolism and exerts a hepatoprotective effect in this model of postmenopausal obesity. RAMP3 may thus be a useful therapeutic target for treatment of postmenopausal obesity and metabolic disorders.
- Published
- 2018
15. Production of functional eggs and sperm from in vitro-expanded type A spermatogonia in rainbow trout
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Masaru Yagisawa, Yoshiko Iwasaki-Takahashi, Goro Yoshizaki, Akira Banba, Ryo Fujihara, Akihiro Yamauchi, Delgado M. Valdez Jr, Kasumi Takahashi, Masaya Watanabe, Takafumi Okabe, and Shinya Shikina
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Male ,0301 basic medicine ,endocrine system ,animal diseases ,Medicine (miscellaneous) ,In Vitro Techniques ,Article ,General Biochemistry, Genetics and Molecular Biology ,Germline ,Cryopreservation ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Animals ,Spermatogenesis ,lcsh:QH301-705.5 ,Ovum ,Transdifferentiation ,biology ,urogenital system ,fungi ,Sertoli cell ,biology.organism_classification ,Spermatozoa ,Sperm ,Spermatogonia ,Cell biology ,Transplantation ,Trout ,030104 developmental biology ,medicine.anatomical_structure ,lcsh:Biology (General) ,Oncorhynchus mykiss ,030220 oncology & carcinogenesis ,Female ,Rainbow trout ,Stem cell ,General Agricultural and Biological Sciences - Abstract
Combining cryopreservation of germline stem cells (GSCs) with their subsequent transplantation into recipient fish is a powerful tool for long-term preservation of genetic resources of endangered fishes. However, application of this technique has been limited because endangered species sometimes have small gonads and do not supply enough GSCs to be used for transplantation. This limitation could be overcome by expanding GSCs in vitro, though this has been difficult due to the complexity of reconstructing the gonadal microenvironment that surrounds GSCs. Here, we describe a novel method of in vitro expansion of rainbow trout GSCs using a feeder layer derived from Sertoli cells and a culture medium containing trout plasma. A transplantation assay demonstrated that the in vitro-expanded GSCs exhibited stem cell activity and potency to produce functional eggs, sperm, and eventually healthy offspring. In vitro expansion of GSCs can aid in rescuing fishes that are on the verge of extinction., Yoshiko Iwasaki-Takahashi et al. report the production of fertilization-capable eggs and sperm from rainbow trout spermatagonia, for application to endangered species preservation. Their method avoids the need for limited numbers of germline stem cells for transplantation, instead allowing in vitro expansion of these cells using a Sertoli cell-derived feeder layer.
- Published
- 2020
16. Adrenomedullin-Receptor Activity-Modifying Protein 2 System Ameliorates Subretinal Fibrosis by Suppressing Epithelial-Mesenchymal Transition in Age-Related Macular Degeneration
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Megumu Tanaka, Akira Imai, Kazutaka Hirabayashi, Yunlu Zhao, Masaaki Tanaka, Akihiro Yamauchi, Yuka Ichikawa-Shindo, Kohsuke Aruga, Hisaka Kawate, Yasuhiro Iesato, Takayuki Sakurai, Akiko Kamiyoshi, Takayuki Shindo, Toshinori Murata, Yuichi Toriyama, Shinji Kakihara, Nanqi Cui, and Yangxuan Wei
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0301 basic medicine ,Epithelial-Mesenchymal Transition ,genetic structures ,medicine.medical_treatment ,Retinal Pigment Epithelium ,Receptor Activity-Modifying Protein 2 ,Pathology and Forensic Medicine ,03 medical and health sciences ,Adrenomedullin ,Macular Degeneration ,0302 clinical medicine ,Fibrosis ,medicine ,Animals ,Humans ,Epithelial–mesenchymal transition ,Mice, Knockout ,business.industry ,Growth factor ,Macular degeneration ,medicine.disease ,eye diseases ,Choroidal Neovascularization ,Disease Models, Animal ,030104 developmental biology ,Choroidal neovascularization ,RAMP2 ,Knockout mouse ,Intravitreal Injections ,030221 ophthalmology & optometry ,Cancer research ,sense organs ,medicine.symptom ,business - Abstract
Age-related macular degeneration (AMD) is a leading cause of visual impairment. Anti–vascular endothelial growth factor drugs used to treat AMD carry the risk of inducing subretinal fibrosis. We investigated the use of adrenomedullin (AM), a vasoactive peptide, and its receptor activity-modifying protein 2, RAMP2, which regulate vascular homeostasis and suppress fibrosis. The therapeutic potential of the AM-RAMP2 system was evaluated after laser-induced choroidal neovascularization (LI-CNV), a mouse model of AMD. Neovascular formation, subretinal fibrosis, and macrophage invasion were all enhanced in both AM and RAMP2 knockout mice compared with those in wild-type mice. These pathologic changes were suppressed by intravitreal injection of AM. Comprehensive gene expression analysis of the choroid after LI-CNV with or without AM administration revealed that fibrosis-related molecules, including Tgfb, Cxcr4, Ccn2, and Thbs1, were all down-regulated by AM. In retinal pigment epithelial cells, co-administration of transforming growth factor-β and tumor necrosis factor-α induced epithelial-mesenchymal transition, which was also prevented by AM. Finally, transforming growth factor-β and C-X-C chemokine receptor type 4 (CXCR4) inhibitors eliminated the difference in subretinal fibrosis between RAMP2 knockout and wild-type mice. These findings suggest the AM-RAMP2 system suppresses subretinal fibrosis in LI-CNV by suppressing epithelial-mesenchymal transition.
- Published
- 2020
17. Adrenomedullin Suppresses Vascular Endothelial Growth Factor–Induced Vascular Hyperpermeability and Inflammation in Retinopathy
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Akira Imai, Teng Liu, Toshinori Murata, Yuka Ichikawa-Shindo, Megumu Tanaka, Xian Xian, Hisaka Kawate, Takayuki Shindo, Takayuki Sakurai, Yuichi Toriyama, Keiya Tanimura, Tian Liu, Nanqi Cui, Liuyu Zhai, Yasuhiro Iesato, Akihiro Yamauchi, Kun Dai, Kazutaka Hirabayashi, and Akiko Kamiyoshi
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Male ,Vascular Endothelial Growth Factor A ,0301 basic medicine ,medicine.medical_specialty ,genetic structures ,Vasodilator Agents ,Mice, Transgenic ,Vascular permeability ,Inflammation ,Diabetes Mellitus, Experimental ,Pathology and Forensic Medicine ,Capillary Permeability ,Adrenomedullin ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Internal medicine ,Electric Impedance ,Animals ,Medicine ,Cells, Cultured ,Diabetic Retinopathy ,business.industry ,NF-kappa B ,Retinitis ,Endothelial Cells ,medicine.disease ,eye diseases ,Mice, Inbred C57BL ,Vascular endothelial growth factor ,Vascular endothelial growth factor B ,Endothelial stem cell ,Vascular endothelial growth factor A ,030104 developmental biology ,Endocrinology ,chemistry ,Intravitreal Injections ,030221 ophthalmology & optometry ,medicine.symptom ,business ,Retinopathy - Abstract
Diabetic macular edema (DME) is caused by blood-retinal barrier breakdown associated with retinal vascular hyperpermeability and inflammation, and it is the major cause of visual dysfunction in diabetic retinopathy. Adrenomedullin (ADM) is an endogenous peptide first identified as a strong vasodilator. ADM is expressed in the eyes and is up-regulated in various eye diseases, although the pathophysiological significance is largely unknown. We investigated the effect of ADM on DME. In Kimba mice, which overexpress human vascular endothelial growth factor in their retinas, the capillary dropout, vascular leakage, and vascular fragility characteristic of diabetic retinopathy were observed. Intravitreal or systemic administration of ADM to Kimba mice ameliorated both the capillary dropout and vascular leakage. Evaluation of the transendothelial electrical resistance and fluorescein isothiocyanate-dextran permeability of an endothelial cell monolayer using TR-iBRB retinal capillary endothelial cells revealed that vascular endothelial growth factor enhanced vascular permeability but that co-administration of ADM suppressed the effect, in part by enhancing tight junction formation between endothelial cells. In addition, a comprehensive PCR array analysis showed that ADM administration suppressed various molecules related to inflammation and NF-κB signaling within retinas. From these results, we suggest that by exerting inhibitory effects on retinal inflammation, vascular permeability, and blood-retinal barrier breakdown, ADM could serve as a novel therapeutic agent for the treatment of DME.
- Published
- 2017
18. Endogenous Calcitonin Gene-Related Peptide Regulates Lipid Metabolism and Energy Homeostasis in Male Mice
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Kazutaka Hirabayashi, Xian Xian, Akira Imai, Megumu Tanaka, Akiko Kamiyoshi, Nanqi Cui, Takayuki Sakurai, Kyoko Igarashi, Keiya Tanimura, Tian Liu, Kun Dai, Akihiro Yamauchi, Hisaka Kawate, Yuka Ichikawa-Shindo, Takayuki Shindo, Liuyu Zhai, Lei Yang, and Teng Liu
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Male ,0301 basic medicine ,medicine.medical_specialty ,Adipose Tissue, White ,Calcitonin Gene-Related Peptide ,Adipose tissue ,White adipose tissue ,Calcitonin gene-related peptide ,Diet, High-Fat ,Energy homeostasis ,Cardiovascular Physiological Phenomena ,Mice ,03 medical and health sciences ,Oxygen Consumption ,0302 clinical medicine ,Endocrinology ,Internal medicine ,medicine ,Animals ,Homeostasis ,Calcitonin receptor ,Mice, Knockout ,integumentary system ,Adiponectin ,Chemistry ,Leptin ,Body Weight ,Lipid Metabolism ,Up-Regulation ,Mice, Inbred C57BL ,Glucose ,030104 developmental biology ,nervous system ,Calcitonin ,Energy Metabolism ,030217 neurology & neurosurgery - Abstract
Calcitonin gene-related peptide (CGRP) is a bioactive peptide produced by alternative splicing of the primary transcript of the calcitonin/CGRP gene. CGRP is largely distributed in the cardiovascular and nervous systems, where it acts as a regulatory factor. CGRP is also expressed in organs and tissues involved in metabolic regulation, including white adipose tissue (WAT), where its function is largely unknown. In this study, we examined the effects of endogenous CGRP on metabolic function. When we administered a high-fat diet to CGRP-specific knockout (CGRP-/-) and wild-type (WT) mice for 10 weeks, we observed that food intake did not differ between the two groups, but body weight and visceral fat weight were significantly lower in CGRP-/- mice. Fatty liver changes were less severe in CGRP-/- mice, which also showed lower serum insulin and leptin levels. Glucose tolerance and insulin sensitivity were better in CGRP-/- than WT mice, and expired gas analysis revealed greater oxygen consumption by CGRP-/- mice. Adipocyte hypertrophy was suppressed in CGRP-/- mice, while expression of β-3-adrenergic receptor, hormone-sensitive lipase and adiponectin was enhanced. Isoproterenol-induced glycerol release from WAT was higher in CGRP-/- than WT mice, and CGRP-/- mice showed elevated sympathetic nervous activity. β-receptor-blockade canceled the beneficial effects of CGRP deletion on obesity. These results suggest that, in addition to its actions in the cardiovascular system, endogenous CGRP is a key regulator of metabolism and energy homeostasis in vivo.
- Published
- 2017
19. Endogenous Calcitonin Gene-Related Peptide Deficiency Exacerbates Postoperative Lymphedema by Suppressing Lymphatic Capillary Formation and M2 Macrophage Accumulation
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Satoshi Tanaka, Takayuki Sakurai, Shinji Kakihara, Megumu Tanaka, Nanqi Cui, Shuhei Matsui, Akihiro Yamauchi, Yuka Ichikawa-Shindo, Keisei Nakamura, Kumiko Ishida, Hisaka Kawate, Masaaki Tanaka, Kun Dai, Takayuki Shindo, Yangxuan Wei, Akiko Kamiyoshi, and Mikito Kawamata
- Subjects
0301 basic medicine ,Male ,medicine.medical_specialty ,Calcitonin Gene-Related Peptide ,Neuropeptide ,030204 cardiovascular system & hematology ,Calcitonin gene-related peptide ,Pathology and Forensic Medicine ,03 medical and health sciences ,Mice ,0302 clinical medicine ,Postoperative Complications ,Internal medicine ,Edema ,medicine ,Lymphatic vessel ,Animals ,Lymphedema ,Lymphangiogenesis ,Lymphatic Vessels ,Mice, Knockout ,integumentary system ,business.industry ,Macrophages ,medicine.disease ,Lymphatic Capillary ,Mice, Inbred C57BL ,Disease Models, Animal ,030104 developmental biology ,Lymphatic system ,Endocrinology ,medicine.anatomical_structure ,nervous system ,Calcitonin ,medicine.symptom ,business - Abstract
Lymphedema is a chronic condition caused by disruption of lymphatic vessels, which often occurs after invasive surgery. Calcitonin gene-related peptide (CGRP) is a 37-amino acid peptide produced by alternative splicing of the primary transcript of the calcitonin/CGRP gene (Calca). CGRP was initially identified as a neuropeptide released primarily from sensory nerves and involved in regulating pathophysiological nociceptive pain. However, recent studies have shown CGRP is also released from a variety of other cells and possesses multiple functions. In this study, CGRP knockout (-/-) mice were used to show the actions of endogenous CGRP in postoperative lymphedema. After generating a mouse postoperative tail lymphedema model, the edema was observed to be more severe in CGRP-/- mice than in wild-type mice. Numbers of lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1)-positive lymphatic capillaries were decreased and lymphatic capillary formation-related factors were down-regulated in CGRP-/- mice. In addition, accumulation of M2 but not M1 macrophages was selectively reduced in the edematous tissue of CGRP-/- mice. Selective depletion of M2 macrophages decreased lymphatic capillary formation and worsened lymphedema in wild-type mice but not CGRP-/- mice, where numbers of M2 macrophages were already diminished. These findings suggest that endogenous CGRP acts to ameliorate postoperative lymphedema by enhancing lymphatic capillary formation and that M2 macrophages play critical roles. CGRP may be a useful therapeutic target for the treatment of postoperative lymphedema.
- Published
- 2019
20. Porcine placental extract facilitates memory and learning in aged mice
- Author
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Eiichi Hirano, Akihiro Yamauchi, Hong Seok Lim, Koji Tamada, Takayuki Shindo, Chihiro Tohda, Takahiro Tone, Yoichi Mizukami, Koji Sugimoto, and Taiichi Kaku
- Subjects
0301 basic medicine ,medicine.medical_specialty ,memory ,RNA‐seq ,hippocampus ,aging ,porcine placental extract ,Central nervous system ,EGR1 ,Hippocampus ,lcsh:TX341-641 ,Hippocampal formation ,Biology ,03 medical and health sciences ,0302 clinical medicine ,Downregulation and upregulation ,Internal medicine ,medicine ,Original Research ,Dentate gyrus ,Vascular endothelial growth factor A ,030104 developmental biology ,Endocrinology ,medicine.anatomical_structure ,GADD45B ,lcsh:Nutrition. Foods and food supply ,030217 neurology & neurosurgery ,Food Science - Abstract
Aging induces a decline in both memory and learning ability without predisposing an individual to diseases of the central nervous system, such as dementia. This decline can have a variety of adverse effects on daily life, and it can also gradually affect the individual and the people they are surrounded by. Since recent evidence indicated that placental extract has effects on brain function such as memory, we hypothesized that placental extract could ameliorate the age‐associated reduction in cognitive function in aging. Here, we investigated the effect of new modified porcine placental extract (SD‐F) on memory ability in aged mice at both the behavioral and molecular levels. Our results revealed that SD‐F significantly enhanced memory ability in the object recognition and object location tasks in a dose‐dependent manner in aged mice relative to controls. The numbers of Nissl‐positive cells in the hippocampal cornu ammonis 3 (CA3) and dentate gyrus (DG) regions were increased in SD‐F‐treated aged mice relative to controls. RNA‐seq analysis of the hippocampus of aged mice identified 542 differentially expressed genes, of which 216 were up‐regulated and 326 were down‐regulated in SD‐F‐treated mice relative to controls. Of the 216 up‐regulated genes, we identified four characteristic genes directly related to memory, including early growth response protein 1 (Egr1), growth arrest and DNA‐damage‐inducible, beta (Gadd45b), NGFI‐A binding protein 2 (Nab2), and vascular endothelial growth factor a (Vegfa). These results suggest that the efficacy of SD‐F involves upregulation of these genes.
- Published
- 2019
21. Placental extract suppresses cardiac hypertrophy and fibrosis in an angiotensin II-induced cachexia model in mice
- Author
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Akiko Kamiyoshi, Eiichi Hirano, Takayuki Shindo, Akihiro Yamauchi, Takayuki Sakurai, Hong Seok Lim, Hiroyuki Miyazaki, and Taiichi Kaku
- Subjects
0301 basic medicine ,musculoskeletal diseases ,medicine.medical_specialty ,Cirrhosis ,Cachexia ,Cardiac fibrosis ,Biochemistry ,Article ,03 medical and health sciences ,0302 clinical medicine ,Weight loss ,Fibrosis ,Internal medicine ,medicine ,lcsh:Social sciences (General) ,lcsh:Science (General) ,Multidisciplinary ,business.industry ,Angiotensin II ,Metabolic disorder ,medicine.disease ,Human placenta extract ,Cardiac hypertrophy ,030104 developmental biology ,Endocrinology ,Heart failure ,cardiovascular system ,lcsh:H1-99 ,medicine.symptom ,business ,030217 neurology & neurosurgery ,hormones, hormone substitutes, and hormone antagonists ,lcsh:Q1-390 - Abstract
Cachexia is an intractable metabolic disorder that causes extreme weight loss. It is a symptom of many chronic diseases, including cancer, liver failure, congestive heart failure and chronic kidney disease, and there is as yet no effective treatment. While the mechanisms underlying cachexia are complex, it is often accompanied by elevated angiotensin II (Ang II). Human placental extract (HPE) is a source of numerous biologically active molecules and has been used clinically to treat chronic hepatitis, liver cirrhosis and other chronic diseases. Here, we investigated the effects of HPE in an Ang II-induced cachexia model in mice. HPE treatment preserved both fat mass and lean body mass and suppressed weight loss in the cachexia model, though food intake was unaffected. Ang II infusion also caused cardiac hypertrophy and fibrosis. HPE suppressed these effects as well as Ang II-induced cardiac expression of genes related to heart failure and cardiac remodeling. HPE also reversed Ang II-induced downregulation of mitochondria-related molecules and suppressed cardiac inflammation and oxidative stress. HPE administration may thus be an effective approach to the treatment of cachexia, cardiac hypertrophy and fibrosis., Article, Heliyon 5(10) : e02655-(2019)
- Published
- 2018
22. The endothelial adrenomedullin-RAMP2 system regulates vascular integrity and suppresses tumour metastasis
- Author
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Akiko Kamiyoshi, Kazutaka Hirabayashi, Shun'ichiro Taniguchi, Akira Imai, Yuka Ichikawa-Shindo, Xian Xian, Shinji Owa, Teruhide Koyama, Takayuki Sakurai, Akihiro Yamauchi, Megumu Tanaka, Kyoko Igarashi, Tian Liu, Liuyu Zhai, Hisaka Kawate, and Takayuki Shindo
- Subjects
0301 basic medicine ,Pathology ,medicine.medical_specialty ,Endothelium ,Physiology ,Angiogenesis ,Inflammation ,Vascular permeability ,Biology ,Receptor Activity-Modifying Protein 2 ,Metastasis ,Capillary Permeability ,Adrenomedullin ,03 medical and health sciences ,0302 clinical medicine ,Cell Movement ,Physiology (medical) ,medicine ,Animals ,Homeostasis ,Neoplasm Metastasis ,Cell adhesion ,Neovascularization, Pathologic ,Endothelial Cells ,medicine.disease ,Mice, Inbred C57BL ,Endothelial stem cell ,030104 developmental biology ,medicine.anatomical_structure ,RAMP2 ,030220 oncology & carcinogenesis ,medicine.symptom ,Cardiology and Cardiovascular Medicine - Abstract
Aims Controlling vascular integrity is expected to be a novel therapeutic target of cancers as well as cardiovascular diseases. Adrenomedullin (AM) and its receptor-modulating protein, RAMP2, have been identified as essential mediators of cardiovascular homeostasis. In this study, we used inducible vascular endothelial cell-specific RAMP2 knockout (DI-E-RAMP2−/−) mice to clarify the contribution made by the endogenous AM-RAMP2 system to angiogenesis and metastasis. Methods and results Subcutaneously transplanted sarcoma or melanoma cells showed less growth and angiogenesis in DI-E-RAMP2−/− than in control mice. On the other hand, after the transplantation of B16BL6 melanoma cells into hindlimb footpads, spontaneous metastasis to the lung was enhanced in DI-E-RAMP2−/− mice. Early after RAMP2 gene deletion, DI-E-RAMP2−/− mice showed enhanced vascular permeability, endothelial–mesenchymal transition (EndMT)-like change, and systemic oedema. Within the lungs of DI-E-RAMP2−/− mice, pulmonary endothelial cells were deformed, and inflammatory cells infiltrated the vessel walls and expressed the chemotactic factors S100A8/9 and SAA3, which attract tumour cells and mediate the formation of a pre-metastatic niche. Conversely, the overexpression of RAMP2 suppressed tumour cell adhesion to endothelial cells, tumour metastasis, and improved survival. Conclusion These findings indicate that the AM-RAMP2 system regulates vascular integrity, whereas RAMP2 deletion promotes vascular permeability and EndMT-like change within primary lesions and formation of pre-metastatic niches in distant organs by destabilizing the vascular structure and inducing inflammation. Vascular integrity regulated by the AM-RAMP2 system could thus be a hopeful therapeutic target for suppressing tumour metastasis.
- Published
- 2016
23. Development of a mouse iron overload-induced liver injury model and evaluation of the beneficial effects of placenta extract on iron metabolism
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Taiichi Kaku, Takayuki Sakurai, Hong Seok Lim, Akiko Kamiyoshi, Hiroyuki Miyazaki, Eiichi Hirano, Akihiro Yamauchi, and Takayuki Shindo
- Subjects
0301 basic medicine ,medicine.medical_specialty ,Cirrhosis ,Molecular biology ,Inflammation ,medicine.disease_cause ,Article ,Excretion ,03 medical and health sciences ,0302 clinical medicine ,Hepcidin ,Internal medicine ,Parenchyma ,medicine ,lcsh:Social sciences (General) ,lcsh:Science (General) ,Liver injury ,Multidisciplinary ,biology ,business.industry ,medicine.disease ,030104 developmental biology ,Endocrinology ,biology.protein ,lcsh:H1-99 ,Steatohepatitis ,medicine.symptom ,business ,030217 neurology & neurosurgery ,Oxidative stress ,lcsh:Q1-390 - Abstract
Hepatic iron deposition is seen in cases of chronic hepatitis and cirrhosis, and is a hallmark of a poorer prognosis. Iron deposition is also found in non-alcoholic steatohepatitis (NASH) patients. We have now developed a mouse model of NASH with hepatic iron deposition by combining a methione- and choline-deficient (MCD) diet with an iron-overload diet. Using this model, we evaluated the effects of human placenta extract (HPE), which has been shown to ameliorate the pathology of NASH. Four-week-old male C57BL/6 mice were fed the MCD diet with 2% iron for 12 weeks. In liver sections, iron deposition was first detected around the portal vein after 1 week. From there it spread throughout the parenchyma. Biliary iron concentrations were continuously elevated throughout the entire 12-week diet. As a compensatory response, the diet caused elevation of serum hepcidin, which accelerates excretion of iron from the body. Accumulation of F4/80-positive macrophages was detected within the sinusoids from the first week onward, and real-time PCR analysis revealed elevated hepatic expression of genes related inflammation and oxidative stress. In the model mice, HPE treatment led to a marked reduction of hepatic iron deposition with a corresponding increase in biliary iron excretion. Macrophage accumulation was much reduced by HPE treatment, as was the serum oxidation-reduction potential, an index of oxidative stress. These data indicate that by suppressing inflammation, oxidative stress and iron deposition, and enhancing iron excretion, HPE effectively ameliorates iron overload-induced liver injury. HPE administration may thus be an effective strategy for treating NASH., Article, Heliyon 5(5) : e01637-(2019)
- Published
- 2018
24. Development of a Novel Model of Central Retinal Vascular Occlusion and the Therapeutic Potential of the Adrenomedullin-Receptor Activity-Modifying Protein 2 System
- Author
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Hisaka Kawate, Takayuki Shindo, Akira Imai, Akiko Kamiyoshi, Akihiro Yamauchi, Keisei Nakamura, Yasuhiro Iesato, Nanqi Cui, Shuhei Matsui, Takayuki Sakurai, Kun Dai, Yuka Ichikawa-Shindo, Yangxuan Wei, Kazutaka Hirabayashi, Yuichi Toriyama, Toshinori Murata, Masaaki Tanaka, Shiho Iida, and Megumu Tanaka
- Subjects
0301 basic medicine ,medicine.medical_specialty ,Leukocyte adhesion molecule ,Receptor Activity-Modifying Protein 2 ,Pathology and Forensic Medicine ,03 medical and health sciences ,chemistry.chemical_compound ,Adrenomedullin ,Mice ,0302 clinical medicine ,Central retinal vein occlusion ,Edema ,Ophthalmology ,Retinal Vein Occlusion ,medicine ,Animals ,Humans ,Fluorescein Angiography ,Retinal Vascular Occlusion ,Mice, Knockout ,medicine.diagnostic_test ,business.industry ,Retinal ,Fluorescein angiography ,medicine.disease ,eye diseases ,Disease Models, Animal ,030104 developmental biology ,chemistry ,RAMP2 ,030221 ophthalmology & optometry ,medicine.symptom ,business ,Tomography, Optical Coherence - Abstract
Central retinal vein occlusion (CRVO) is an intractable disease that causes visual acuity loss with retinal ischemia, hemorrhage, and edema. In this study, we developed an experimental CRVO model in mice and evaluated the therapeutic potential of the pleiotropic peptide adrenomedullin (ADM) and its receptor activity-modifying protein 2 (RAMP2). The CRVO model, which had phenotypes resembling those seen in the clinic, was produced by combining i.p. injection of Rose bengal, a photoactivator dye enhancing thrombus formation, with laser photocoagulation. Retinal vascular area, analyzed using fluorescein angiography and fluorescein isothiocyanate-perfused retinal flat mounts, was decreased after induction of CRVO but gradually recovered from day 1 to 7. Measurements of retinal thickness using optical coherence tomography and histology revealed prominent edema early after CRVO, followed by gradual atrophy. Reperfusion after CRVO was diminished in Adm and Ramp2 knockout (KO) mice but was increased by exogenous ADM administration. CRVO also increased expression of a coagulation factor, oxidative stress markers, and a leukocyte adhesion molecule in both wild-type and Adm KO mice, and the effect was more pronounced in Adm KO mice. Using retinal capillary endothelial cells, ADM was found to directly suppress retinal endothelial injury. The retinoprotective effects of the Adm-Ramp2 system make it a novel therapeutic target for the treatment of CRVO.
- Published
- 2018
25. Mechanochemically Prepared Li
- Author
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Atsushi, Sakuda, Akihiro, Yamauchi, So, Yubuchi, Naoto, Kitamura, Yasushi, Idemoto, Akitoshi, Hayashi, and Masahiro, Tatsumisago
- Subjects
Article - Abstract
Solid electrolytes with compositions of (100 – x)(0.75Li2S·0.25P2S5)·xLiBH4 (mol %, 0 ≤ x ≤ 100) were mechanochemically prepared from the 75Li2S·25P2S5 (mol %) glass and LiBH4 crystal. The samples with x ≥ 43 have crystalline phases and those with x ≤ 33 formed a glassy phase. The crystalline phase was identified as argyrodite Li6PS5(BH4). The x = 50 sample formed a crystalline phase and demonstrated a high lithium-ion conductivity of 1.8 × 10–3 S cm–1 at 25 °C with an activation energy of 16 kJ·mol–1. The argyrodite-type crystal with a BH4– anion that occupies the halide site is a novel and promising solid electrolyte.
- Published
- 2018
26. Endogenous calcitonin gene-related peptide suppresses ischemic brain injuries and progression of cognitive decline
- Author
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Kazutaka Hirabayashi, Takayuki Shindo, Kun Dai, Akihiro Yamauchi, Liuyu Zhai, Hisaka Kawate, Xian Xian, Megumu Tanaka, Takayuki Sakurai, Teng Liu, Haruka Tomiyama, Masaaki Tanaka, Keiya Tanimura, Yangxuan Wei, Nanqi Cui, Yuka Ichikawa-Shindo, Kyoko Igarashi, and Akiko Kamiyoshi
- Subjects
0301 basic medicine ,Male ,medicine.medical_specialty ,Physiology ,Calcitonin Gene-Related Peptide ,Neovascularization, Physiologic ,Peptide ,Vasodilation ,Endogeny ,Calcitonin gene-related peptide ,Brain Ischemia ,03 medical and health sciences ,Mice ,0302 clinical medicine ,Internal medicine ,Internal Medicine ,Medicine ,Animals ,Cognitive Dysfunction ,Cognitive decline ,Maze Learning ,Gene ,chemistry.chemical_classification ,Mice, Knockout ,Neurons ,integumentary system ,Cell Death ,business.industry ,Alternative splicing ,Oxidative Stress ,030104 developmental biology ,Endocrinology ,nervous system ,chemistry ,Calcitonin ,Cerebrovascular Circulation ,Disease Progression ,Cytokines ,Cardiology and Cardiovascular Medicine ,business ,030217 neurology & neurosurgery - Abstract
Calcitonin gene-related peptide (CGRP) is a 37-amino acid peptide and produced by alternative splicing of the transcript of the calcitonin/CGRP gene. Originally identified as a strong vasodilatory and hypotensive peptide, CGRP is now known to be a pleiotropic molecule distributed in various organs, including the brain.In this study, we used CGRP knockout mice (CGRP-/-) to examine the actions of endogenous CGRP during cerebral ischemia. To induce acute and chronic cerebral ischemia, mice were subjected to middle cerebral artery occlusion (MCAO) and bilateral common carotid artery stenosis (BCAS).In the cerebral cortex of wild-type mice, CGRP expression was upregulated after acute infarction. In CGRP-/- subjected to MCAO or BCAS, recovery of cerebral blood flow was slower and exhibited more extensive neuronal cell death. Expression of the inflammatory cytokines was higher in CGRP-/- than wild type in the acute phase of ischemia. Pathological analysis during the chronic phase revealed more extensive neuronal cell loss and demyelination and higher levels of oxidative stress in CGRP-/- than wild-type. CGRP-/- also showed less compensatory capillary growth. In an eight-arm radial maze test, CGRP-/- exhibited poorer reference memory than wild-type. On the other hand, CGRP administration promoted cerebral blood flow recovery after cerebral ischemia. We also found that CGRP directly inhibited the cell death of primary cortical neurons.These results indicate endogenous CGRP is protective against ischemia-induced neuronal cell injury. CGRP could, thus, be a novel candidate for use in the treatment of both cerebral ischemia and progression of cognitive decline.
- Published
- 2017
27. Pathophysiological Function of Endogenous Calcitonin Gene–Related Peptide in Ocular Vascular Diseases
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Xian Xian, Megumu Tanaka, Kyoko Igarashi, Akira Imai, Yasuhiro Iesato, Takayuki Sakurai, Akihiro Yamauchi, Takayuki Shindo, Yuka Ichikawa-Shindo, Toshinori Murata, Yuichi Toriyama, Shinji Owa, Liuyu Zhai, Akiko Kamiyoshi, Tian Liu, and Hisaka Kawate
- Subjects
Male ,medicine.medical_specialty ,genetic structures ,Angiogenesis ,Calcitonin Gene-Related Peptide ,Inflammation ,Calcitonin gene-related peptide ,Retina ,Pathology and Forensic Medicine ,Mice ,Internal medicine ,medicine ,Animals ,Mice, Knockout ,integumentary system ,business.industry ,Retinal Vessels ,Choroidal Neovascularization ,eye diseases ,Adrenomedullin ,Disease Models, Animal ,Choroidal neovascularization ,medicine.anatomical_structure ,Endocrinology ,nervous system ,Calcitonin ,Tumor necrosis factor alpha ,sense organs ,medicine.symptom ,business ,Receptors, Calcitonin Gene-Related Peptide - Abstract
Calcitonin gene–related peptide (CGRP; official name CALCA) has a variety of functions and exhibits both angiogenic and anti-inflammatory properties. We previously reported the angiogenic effects of the CGRP family peptide adrenomedullin in oxygen-induced retinopathy; however, the effects of CGRP on ocular angiogenesis remain unknown. Herein, we used CGRP knockout (CGRP −/− ) mice to investigate the roles of CGRP in ocular vascular disease. Observation of pathological retinal angiogenesis in the oxygen-induced retinopathy model revealed no difference between CGRP −/− and wild-type mice. However, much higher levels of the CGRP receptor were present in the choroid than the retina. Laser-induced choroidal neovascularization (CNV), a model of exudative age-related macular degeneration, revealed more severe CNV lesions in CGRP −/− than wild-type mice, and fluorescein angiography showed greater leakage from CNV in CGRP −/− . In addition, macrophage infiltration and tumor necrosis factor (TNF)-α production were enhanced within the CNV lesions in CGRP −/− mice, and the TNF-α, in turn, suppressed the barrier formation of retinal pigment epithelial cells. In vivo , CGRP administration suppressed CNV formation, and CGRP also dose dependently suppressed TNF-α production by isolated macrophages . From these data, we conclude that CGRP suppresses the development of leaky CNV through negative regulation of inflammation. CGRP may thus be a promising therapeutic agent for the treatment of ocular vascular diseases associated with inflammation.
- Published
- 2015
28. Blood kinetics of steroid hormones during thoracotomy with cardiopulmonary bypass
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Makoto Hibiya, Akihiro Yamauchi, Tomoaki Yamashiro, Yasuhiro Ito, Saori Ishida, Takashi Watanabe, Takuya Fujiura, Misako Sugiura, Takashi Ishikawa, Masaru Yamamoto, Mika Noda, Masahito Toyozaki, and Kana Ohno
- Subjects
medicine.medical_specialty ,Aldosterone ,business.industry ,medicine.medical_treatment ,Steroid ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,Anesthesia ,Internal medicine ,medicine ,Cardiopulmonary bypass ,Cardiology ,Androstenedione ,Thoracotomy ,business ,Hormone - Published
- 2015
29. Pathophysiological roles of adrenomedullin-RAMP2 system in acute and chronic cerebral ischemia
- Author
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Takayuki Sakurai, Akira Imai, Teruhide Koyama, Akiko Kamiyoshi, Yuichi Toriyama, Tian Liu, Ryuichi Uetake, Takayuki Shindo, Masafumi Ihara, Xian Xian, Liuyu Zhai, Hisaka Kawate, Shinji Owa, Megumu Tanaka, Akihiro Yamauchi, Kyoko Igarashi, and Yuka Ichikawa-Shindo
- Subjects
medicine.medical_specialty ,Physiology ,Ischemia ,Receptor Activity-Modifying Protein 2 ,medicine.disease_cause ,Biochemistry ,Brain Ischemia ,Adrenomedullin ,Mice ,Cellular and Molecular Neuroscience ,Endocrinology ,Internal medicine ,Animals ,Humans ,Medicine ,Carotid Stenosis ,Receptors, Adrenomedullin ,Cerebral perfusion pressure ,Mice, Knockout ,Neurons ,Receptor activity-modifying protein ,Cell Death ,business.industry ,Brain ,medicine.disease ,Oxidative Stress ,medicine.anatomical_structure ,Cerebral blood flow ,RAMP2 ,Anesthesia ,Blood Vessels ,business ,Oxidative stress ,Blood vessel - Abstract
The accessory protein RAMP2 is a component of the CLR/RAMP2 dimeric adrenomedullin (AM) receptor and is the primary determinant of the vascular functionality of AM. RAMP2 is highly expressed in the brain; however, its function there remains unclear. We therefore used heterozygous RAMP2 knockout (RAMP2+/-) mice, in which RAMP2 expression was reduced by half, to examine the actions of the endogenous AM-RAMP2 system in cerebral ischemia. To induce acute or chronic ischemia, mice were subjected to middle cerebral artery occlusion (MCAO) or bilateral common carotid artery stenosis (BCAS), respectively. In RAMP2+/- mice subjected to MCAO, recovery of cerebral blood flow (CBF) was slower than in WT mice. AM gene expression was upregulated after infarction in both genotypes, but the increase was greater in RAMP2+/- mice. Pathological analysis revealed severe nerve cell death and demyelination, and a higher level of oxidative stress in RAMP2+/- mice. In RAMP2+/- mice subjected to BCAS, recovery of cerebral perfusion was slower and less complete than in WT mice. In an 8-arm radial maze test, RAMP2+/- mice required more time to solve the maze and showed poorer reference memory. They also showed greater reductions in nerve cells and less compensatory capillary growth than WT mice. These results indicate the AM-RAMP2 system works to protect nerve cells from both acute and chronic cerebral ischemia by maintaining CBF, suppressing oxidative stress, and in the case of chronic ischemia, enhancing capillary growth.
- Published
- 2014
30. Functional differentiation of RAMP2 and RAMP3 in their regulation of the vascular system
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Liuyu Zhai, Akihiro Yamauchi, Megumu Tanaka, Takuma Arai, Akiko Kamiyoshi, Kyoko Igarashi, Yuichi Toriyama, Takayuki Sakurai, Yuka Ichikawa-Shindo, Xian Xian, Tian Liu, Shinji Owa, Takayuki Shindo, Hisaka Kawate, and Akira Imai
- Subjects
Male ,medicine.medical_specialty ,Angiogenesis ,government.form_of_government ,Biology ,Receptor Activity-Modifying Protein 2 ,Receptor Activity-Modifying Protein 3 ,Ischemia ,Cell Line, Tumor ,Internal medicine ,medicine ,Animals ,Lymphedema ,Receptor ,Molecular Biology ,Cell Proliferation ,Mice, Knockout ,Receptor activity-modifying protein ,Neovascularization, Pathologic ,Hindlimb ,Adrenomedullin ,Lymphatic Endothelium ,Lymphatic system ,medicine.anatomical_structure ,Endocrinology ,RAMP2 ,government ,Female ,Genes, Lethal ,Endothelium, Lymphatic ,Cardiology and Cardiovascular Medicine ,Neoplasm Transplantation ,Blood vessel - Abstract
Adrenomedullin (AM) is a vasoactive peptide that possesses various bioactivities. AM receptors are dimers consisting of CLR with one of two accessory proteins, RAMP2 or RAMP3. The functional difference between CLR/RAMP2 and CLR/RAMP3 and the relationship between the two receptors remain unclear. To address these issues, we generated RAMP2 and RAMP3 knockout (-/-) mice and have been studying their physiological activities in the vascular system. AM-/- and RAMP2-/- mice die in utero due to blood vessel abnormalities, which is indicative of their essential roles in vascular development. In contrast, RAMP3-/- mice were born normally without any major abnormalities. In adult RAMP3-/- mice, postnatal angiogenesis was normal, but lymphangiography using indocyanine green (ICG) showed delayed drainage of subcutaneous lymphatic vessels. Moreover, chyle transport by intestinal lymphatics was delayed in RAMP3-/- mice, which also showed more severe interstitial edema than wild-type mice in a tail lymphedema model, with characteristic dilatation of lymphatic capillaries and accumulation of inflammatory cells. In scratch-wound assays, migration of isolated RAMP3-/- lymphatic endothelial cells was delayed as compared to wild-type cells, and AM administration failed to enhance the re-endothelialization. The delay in re-endothelialization was due to a primary migration defect rather than a decrease in proliferation. These results suggest that RAMP3 regulates drainage through lymphatic vessels, and that the AM-RAMP3 system could be a novel therapeutic target for controlling postoperative lymphedema.
- Published
- 2014
31. Diminutive intramucosal invasive (Tis) sigmoid colon carcinoma
- Author
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Akihiro Yamauchi, Kenichi Suzuki, Yuichi Mori, Masashi Misawa, Shigeharu Hamatani, Hideyuki Miyachi, Yuichi Fukami, Kenta Igarashi, Shin-ei Kudo, Kunihiko Wakamura, Takemasa Hayashi, Tamotsu Sugai, Toyoki Kudo, and Atsushi Katagiri
- Subjects
Pathology ,medicine.medical_specialty ,Muscularis mucosae ,Endoscopic Mucosal Resection ,Endoscopic mucosal resection ,Adenocarcinoma ,Lesion ,03 medical and health sciences ,Narrow Band Imaging ,0302 clinical medicine ,Colon, Sigmoid ,Atypia ,Carcinoma ,Medicine ,Humans ,Neoplasm Invasiveness ,Intestinal Mucosa ,Coloring Agents ,business.industry ,Gastroenterology ,Sigmoid colon ,General Medicine ,Colonoscopy ,Middle Aged ,medicine.disease ,Sigmoid Neoplasms ,medicine.anatomical_structure ,Dysplasia ,030220 oncology & carcinogenesis ,030211 gastroenterology & hepatology ,Female ,Gentian Violet ,medicine.symptom ,business - Abstract
A 60-year-old woman underwent colonoscopy, which revealed a red, 5-mm protruded lesion in the sigmoid colon, surrounded by white spots in white-light imaging. Indigo carmine spray indicated endoscopic morphological type Is + IIc. The vessel pattern was diagnosed as JNET-type 2B in magnifying narrow-band imaging, and magnified crystal violet-stained images revealed a VI low-grade pit pattern. We endoscopically diagnosed this lesion as an intramucosal or slightly invasive submucosal carcinoma with low confidence, and performed endoscopic mucosal resection to obtain a total biopsy. Hematoxylin and eosin staining of the resected specimen showed that the surface of the lesion was well-differentiated adenocarcinoma. The muscularis mucosae was identified by desmin immunostaining. There was no lymphovascular infiltration. Structural atypia was notable in the invasive front, indicating well-to-moderately differentiated adenocarcinoma, which invaded the lamina muscularis mucosae. In addition, desmoplastic reaction was recognized to be present. The lesion was, therefore, diagnosed as an intramucosal invasive (Tis) carcinoma, rather than high-grade dysplasia, according to the World Health Organization definition.
- Published
- 2017
32. Retrospective analysis of large bowel obstruction or perforation caused by oral preparation for colonoscopy
- Author
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Eiji Hidaka, Yuichi Mori, Takemasa Hayashi, Fumio Ishida, Hatsumi Kamo, Masashi Misawa, Toyoki Kudo, Atsushi Katagiri, Shin-ei Kudo, Tomokazu Hisayuki, Toshiyuki Baba, Kunihiko Wakamura, Akihiro Yamauchi, and Hideyuki Miyachi
- Subjects
Original article ,medicine.medical_specialty ,Abdominal pain ,Constipation ,medicine.diagnostic_test ,business.industry ,General surgery ,medicine.medical_treatment ,Perforation (oil well) ,Colostomy ,Colonoscopy ,Perioperative ,medicine.disease ,Bowel obstruction ,03 medical and health sciences ,0302 clinical medicine ,030220 oncology & carcinogenesis ,Medicine ,030211 gastroenterology & hepatology ,Pharmacology (medical) ,lcsh:Diseases of the digestive system. Gastroenterology ,Risk factor ,medicine.symptom ,lcsh:RC799-869 ,business - Abstract
Background and study aims Patients undergoing bowel preparation for colonoscopy are at risk of potentially severe adverse events such as large-bowel obstruction (LBO) and perforation. These patients usually need emergency surgery and the consequences may be fatal. Little is known about the risk factors for LBO and perforation in these circumstances. We sought to establish the natural history of LBO and perforation caused by oral preparation for colonoscopy. Patients and methods We retrospectively analyzed data from 20 patients with LBO or perforation associated with oral preparation for colonoscopy. All patients were treated at the Showa University Northern Yokohama Hospital (SUNYH) between April 2001 and December 2015. Drugs used for bowel preparation, age, sex, indication for colonoscopy, pathogenesis and treatment were recorded. Results Eighteen of the patients had LBO and 2 had perforation. Fourteen events occurred at SUNYH, which accounted for 0.016 % of patients who underwent bowel preparation during this period. Seventeen patients were symptomatic when the decision to undertake colonoscopy was made (including 7 who complained of constipation and 4 who complained of abdominal pain; 3e were asymptomatic). Nineteen patients ultimately required surgery, 13 within 3 days of presentation. Eleven patients ultimately required colostomy. There was no perioperative mortality in our cases. Conclusion Large bowel obstruction and perforation are rare events associated with oral preparation for colonoscopy, but frequently require surgery. Exacerbation of constipation might be a risk factor for LBO or perforation. Potentially catastrophic situations can be avoided by early detection and treatment.
- Published
- 2017
33. Interface Formation of Unidirectional SiCf/SiC Composites by Electrophoretic Deposition Method
- Author
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Toshio Ogasawara, Akihiro Yamauchi, Toyohiko Yano, Masaki Kotani, Hiroyuki Akimoto, and Katsumi Yoshida
- Subjects
Mechanical property ,Electrophoretic deposition ,Brittleness ,Materials science ,Mechanics of Materials ,Mechanical Engineering ,Sintering ,General Materials Science ,Interphase ,Fiber ,Composite material ,Microstructure ,Toughening - Abstract
C-and BN-interphases on SiC fibers for unidirectional SiCf/SiC composites were formed by EPD process, and their microstructure and mechanical properties were investigated. Whereas the C-SiCf/SiC composites showed a pseudo-ductile fracture behavior with large amount of fiber pullout, the BN-SiCf/SiC composites fractured in a brittle manner without fiber pullout in spite of sufficient thickness of BN interphase. It is inferred from the results of EDS that sintering additives would react with h-BN-interphase, and the interphase did not act effectively for toughening the SiCf/SiC composites.
- Published
- 2014
34. The newly developed MoviPrep can reduce the patients’ burden in the preparation for colonoscopy
- Author
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Kunihiko Wakamura, Yuichi Mori, Masashi Misawa, Atsushi Katagiri, Toshiyuki Baba, Fumio Ishida, Kenta Kodama, Toyoki Kudo, Tomokazu Hisayuki, Shin-ei Kudo, Takemasa Hayashi, Akihiro Yamauchi, Yukiko Shakuo, Makoto Kaga, and Hideyuki Miyachi
- Subjects
medicine.medical_specialty ,medicine.diagnostic_test ,business.industry ,Mechanical Engineering ,General surgery ,Energy Engineering and Power Technology ,Medicine ,Colonoscopy ,Management Science and Operations Research ,business - Published
- 2014
35. Preparation and ionic conductivities of (100 − x)(0.75Li2S·0.25P2S5)·xLiBH4 glass electrolytes
- Author
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Atsushi Sakuda, Akihiro Yamauchi, Akitoshi Hayashi, and Masahiro Tatsumisago
- Subjects
Materials science ,Renewable Energy, Sustainability and the Environment ,Inorganic chemistry ,Analytical chemistry ,Energy Engineering and Power Technology ,Ionic bonding ,Electrolyte ,Conductivity ,Endothermic process ,Crystal ,symbols.namesake ,chemistry.chemical_compound ,chemistry ,Lithium borohydride ,symbols ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Raman spectroscopy ,Electrochemical window - Abstract
(100 − x )(0.75Li 2 S·0.25P 2 S 5 )· x LiBH 4 (0 ≤ x (mol%) ≤ 33) glass electrolytes were prepared from 75Li 2 S·25P 2 S 5 (mol%) glass and LiBH 4 crystal by a mechanical milling technique. The effects of the addition of LiBH 4 on the structures and properties of the glass electrolytes were examined. The DSC curves of the prepared glasses with LiBH 4 did not have the endothermic peak attributable to the phase transition of LiBH 4 crystal. The Raman spectra of the glasses indicated that the glasses included PS 4 3− and BH 4 − ions. The conductivities of the glasses increased with increasing the LiBH 4 content. The glass at the composition of x = 33 showed the highest lithium-ion conductivity of 1.6 × 10 −3 S cm −1 at room temperature. The glass had a wide electrochemical window up to 5 V vs. Li + /Li. An all-solid-state Li/TiS 2 cell using the glass as an electrolyte successfully operated as a secondary battery at 25 °C.
- Published
- 2013
36. Vascular Endothelial Adrenomedullin-RAMP2 System Is Essential for Vascular Integrity and Organ Homeostasis
- Author
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Akihiro Yamauchi, Hisaka Kawate, Ralf H. Adams, Takayuki Shindo, Ayano Okimura, Alfredo Martínez, Nobuyoshi Iinuma, Yuka Ichikawa-Shindo, Yang Lei, Takuma Arai, Megumu Tanaka, Yasuhiro Iesato, Ryuichi Uetake, Kyoko Igarashi, Takahiro Yoshizawa, Yuichi Toriyama, Hayato Kawakami, Teruhide Koyama, Takayuki Sakurai, Akiko Kamiyoshi, Naoki Mochizuki, and Laura Ochoa-Callejero
- Subjects
Vasculitis ,Aging ,Pathology ,medicine.medical_specialty ,Endothelium ,Arteriosclerosis ,Cardiac fibrosis ,Kidney ,Receptor Activity-Modifying Protein 2 ,Adrenomedullin ,Mice ,Antigens, CD ,Fibrosis ,Physiology (medical) ,Leukocytes ,medicine ,Animals ,Edema ,Homeostasis ,Mice, Knockout ,Glomerulosclerosis, Focal Segmental ,business.industry ,Age Factors ,Kidney metabolism ,Cadherins ,medicine.disease ,Vascular endothelial growth factor B ,Disease Models, Animal ,Oxidative Stress ,medicine.anatomical_structure ,RAMP2 ,Knockout mouse ,Endothelium, Vascular ,Cardiology and Cardiovascular Medicine ,business - Abstract
信州大学博士(医学)・学位論文・平成25年3月31日授与(甲第935号)・小山 晃英, Background-Revealing the mechanisms underlying the functional integrity of the vascular system could make available novel therapeutic approaches. We previously showed that knocking out the widely expressed peptide adrenomedullin (AM) or receptor activity-modifying protein 2 (RAMP2), an AM-receptor accessory protein, causes vascular abnormalities and is embryonically lethal. Our aim was to investigate the function of the vascular AM-RAMP2 system directly. Methods and Results-We generated endothelial cell-specific RAMP2 and AM knockout mice (E-RAMP2(-/-) and E-AM(-/-)). Most E-RAMP2(-/-) mice died perinatally. In surviving adults, vasculitis occurred spontaneously. With aging, E-RAMP2(-/-) mice showed severe organ fibrosis with marked oxidative stress and accelerated vascular senescence. Later, liver cirrhosis, cardiac fibrosis, and hydronephrosis developed. We next used a line of drug-inducible E-RAMP2(-/-) mice (DI-E-RAMP2(-/-)) to induce RAMP2 deletion in adults, which enabled us to analyze the initial causes of the aforementioned vascular and organ damage. Early after the induction, pronounced edema with enhanced vascular leakage occurred. In vitro analysis revealed the vascular leakage to be caused by actin disarrangement and detachment of endothelial cells. We found that the AM-RAMP2 system regulates the Rac1-GTP/RhoA-GTP ratio and cortical actin formation and that a defect in this system causes the disruption of actin formation, leading to vascular and organ damage at the chronic stage after the gene deletion. Conclusions-Our findings show that the AM-RAMP2 system is a key determinant of vascular integrity and homeostasis from prenatal stages through adulthood. Furthermore, our models demonstrate how endothelial cells regulate vascular integrity and how their dysregulation leads to organ damage. (Circulation. 2013;127:842-853.), Article, CIRCULATION. 127(7):842-853 (2013)
- Published
- 2013
37. Novel Regulation of Cardiac Metabolism and Homeostasis by the Adrenomedullin-Receptor Activity-Modifying Protein 2 System
- Author
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Tsuyoshi Nakanishi, Megumu Tanaka, Kyoko Igarashi, Akiko Kamiyoshi, Yasuhiro Iesato, Teruhide Koyama, Tsutomu Nakada, Yuichi Toriyama, Hayato Kawakami, Akihiro Yamauchi, Hiroshi Akazawa, Toshihide Kashihara, Ryuichi Uetake, Takayuki Sakurai, Mitsuhiko Yamada, Hiroki Nakanishi, Yuka Ichikawa-Shindo, Takayuki Shindo, Lei Yang, Takahiro Yoshizawa, Hisaka Kawate, and Ryo Taguchi
- Subjects
Cardiomyopathy, Dilated ,medicine.medical_specialty ,Mice, Transgenic ,Mitochondrion ,Biology ,Receptor Activity-Modifying Protein 2 ,Mitochondria, Heart ,Adrenomedullin ,Mice ,chemistry.chemical_compound ,Downregulation and upregulation ,Internal medicine ,Internal Medicine ,medicine ,Cardiolipin ,Animals ,Homeostasis ,Myocytes, Cardiac ,Receptors, Adrenomedullin ,Receptor ,Heart metabolism ,Myocardium ,Mitochondrial Turnover ,Endocrinology ,Mitochondrial biogenesis ,chemistry ,RAMP2 ,Calcium - Abstract
Adrenomedullin (AM) was identified as a vasodilating and hypotensive peptide mainly produced by the cardiovascular system. The AM receptor calcitonin receptor-like receptor associates with receptor activity-modifying protein (RAMP), one of the subtypes of regulatory proteins. Among knockout mice ( −/− ) of RAMPs, only RAMP2 −/− is embryonically lethal with cardiovascular abnormalities that are the same as AM −/− . This suggests that the AM-RAMP2 system is particularly important for the cardiovascular system. Although AM and RAMP2 are highly expressed in the heart from embryo to adulthood, their analysis has been limited by the embryonic lethality of AM −/− and RAMP2 −/− . For this study, we generated inducible cardiac myocyte-specific RAMP2 −/− (C-RAMP2 −/− ). C-RAMP2 −/− exhibited dilated cardiomyopathy-like heart failure with cardiac dilatation and myofibril disruption. C-RAMP2 −/− hearts also showed changes in mitochondrial structure and downregulation of mitochondria-related genes involved in oxidative phosphorylation, β-oxidation, and reactive oxygen species regulation. Furthermore, the heart failure was preceded by changes in peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α), a master regulator of mitochondrial biogenesis. Metabolome and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF-MS) imaging analyses revealed early downregulation of cardiolipin, a mitochondrial membrane-specific lipid. Furthermore, primary-cultured cardiac myocytes from C-RAMP2 −/− showed reduced mitochondrial membrane potential and enhanced reactive oxygen species production in a RAMP2 deletion–dependent manner. C-RAMP2 −/− showed downregulated activation of cAMP response element binding protein (CREB), one of the main regulators of mitochondria-related genes. These data demonstrate that the AM-RAMP2 system is essential for cardiac metabolism and homeostasis. The AM-RAMP2 system is a promising therapeutic target of heart failure.
- Published
- 2013
38. The results of the deep hypothermia intermittent circulatory arrest to chronic thromboembolic pulmonary arterial hypertension
- Author
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Makoto Hibiya, Yasuhiro Ito, Misako Sugiura, Akihiro Yamauchi, Tomoaki Yamashiro, Saori Ishida, Takuya Fujiura, Takashi Ishikawa, Masahito Toyozaki, and Masaru Yamamoto
- Subjects
medicine.medical_specialty ,business.industry ,Internal medicine ,Anesthesia ,Circulatory system ,medicine ,Cardiology ,Hypothermia ,medicine.symptom ,business - Published
- 2013
39. Correlation between circulating steroid hormones and Pao2 during cardiopulmonary bypass
- Author
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Makoto Hibiya, Akihiro Yamauchi, Misako Sugiura, Tomoaki Yamashiro, Yasuhiro Ito, Masaru Yamamoto, Takashi Ishikawa, Masahito Toyozaki, Rihoka Kajiwara, and Saori Ishida
- Subjects
medicine.medical_specialty ,Endocrinology ,business.industry ,law ,medicine.medical_treatment ,Internal medicine ,Cardiopulmonary bypass ,Medicine ,business ,law.invention ,Steroid ,Hormone - Published
- 2013
40. Vasoprotective Activities of the Adrenomedullin-RAMP2 System in Endothelial Cells
- Author
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Takayuki Shindo, Nanqi Cui, Liuyu Zhai, Akihiro Yamauchi, Lei Yang, Teruhide Koyama, Kazutaka Hirabayashi, Hisaka Kawate, Teng Liu, Kun Dai, Takayuki Sakurai, Akiko Kamiyoshi, Keiya Tanimura, Tian Liu, Akira Imai, Megumu Tanaka, Kyoko Igarashi, Xian Xian, and Yuka Ichikawa-Shindo
- Subjects
0301 basic medicine ,Neointima ,Male ,medicine.medical_specialty ,Vascular smooth muscle ,Endothelium ,030204 cardiovascular system & hematology ,Receptor Activity-Modifying Protein 2 ,03 medical and health sciences ,Adrenomedullin ,Mice ,0302 clinical medicine ,Endocrinology ,Internal medicine ,medicine ,Animals ,Humans ,Progenitor cell ,Cells, Cultured ,Neointimal hyperplasia ,Mice, Knockout ,business.industry ,Endothelial Cells ,Vascular System Injuries ,medicine.disease ,Vasoprotective ,Femoral Artery ,Mice, Inbred C57BL ,030104 developmental biology ,medicine.anatomical_structure ,RAMP2 ,Cytoprotection ,business ,Signal Transduction - Abstract
Neointimal hyperplasia is the primary lesion underlying atherosclerosis and restenosis after coronary intervention. We previously described the essential angiogenic function of the adrenomedullin (AM)-receptor activity-modifying protein (RAMP) 2 system. In the present study, we assessed the vasoprotective actions of the endogenous AM-RAMP2 system using a wire-induced vascular injury model. We found that neointima formation and vascular smooth muscle cell proliferation were enhanced in RAMP2+/- male mice. The injured vessels from RAMP2+/- mice showed greater macrophage infiltration, inflammatory cytokine expression, and oxidative stress than vessels from wild-type mice and less re-endothelialization. After endothelial cell-specific RAMP2 deletion in drug-inducible endothelial cell-specific RAMP2-/- (DI-E-RAMP2-/-) male mice, we observed markedly greater neointima formation than in control mice. In addition, neointima formation after vessel injury was enhanced in mice receiving bone marrow transplants from RAMP2+/- or DI-E-RAMP2-/- mice, indicating that bone marrow-derived cells contributed to the enhanced neointima formation. Finally, we found that the AM-RAMP2 system augmented proliferation and migration of endothelial progenitor cells. These results demonstrate that the AM-RAMP2 system exerts crucial vasoprotective effects after vascular injury and could be a therapeutic target for the treatment of vascular diseases.
- Published
- 2016
41. Su1622 Endocytoscopic Diagnosis of Tumor Grading in Early-Stage Colorectal Cancer
- Author
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Atsushi Katagiri, Shinichi Kataoka, Tomoya Sako, Tomoyuki Ishigaki, Shin-ei Kudo, Kenta Igarashi, Kunihiko Wakamura, Shingo Matsudaira, Toshiyuki Baba, Yushi Ogawa, Naoya Toyoshima, Kazuki Kato, Hiroki Nakamura, Maeda Yasuharu, Tomokazu Hisayuki, Kenichi Takeda, Toyoki Kudo, Katsuro Ichimasa, Noriyuki Ogata, Fumihiko Urushibara, Fumio Ishida, Tomonari Cho, Yuta Kouyama, Yusuke Yagawa, Takemasa Hayashi, Akihiro Yamauchi, Yuichi Mori, Masashi Misawa, and Tatsuya Sakurai
- Subjects
Oncology ,medicine.medical_specialty ,Colorectal cancer ,business.industry ,Internal medicine ,Gastroenterology ,medicine ,Tumor Grading ,Radiology, Nuclear Medicine and imaging ,Stage (cooking) ,medicine.disease ,business - Published
- 2017
42. New sports as the care prevention that focused on dementia and mental health : Consideration from elderly persons' Qulority club team
- Author
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Noriko, KIMURA, Masatsugu, SUGITANI, Yukio, ISHIKAWA, Mamoru, AOKI, Eiko, GOTOU, and Akihiro, YAMAUCHI
- Subjects
認知症予防 ,精神的健康 ,mentalhealth ,Qulority ,careprevention ,認知症 ,クロリティー ,dementia - Published
- 2011
43. A Mechanism of Acceleration of Fatigue Crack Growth after Applying Overload
- Author
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Akihiro Yamauchi, Hisashi Miyahara, Tatsujiro Miyazaki, and Chobin Makabe
- Subjects
Cyclic stress ,Materials science ,business.industry ,Mechanical Engineering ,Structural engineering ,Paris' law ,Condensed Matter Physics ,Crack closure ,Acceleration ,Mechanics of Materials ,Residual stress ,mental disorders ,Ultimate tensile strength ,General Materials Science ,Composite material ,business ,Plane stress ,Stress concentration - Abstract
The acceleration mechanism of crack growth after applying overload was investigated under baseline stress ratio R = -1. An overload was applied during fatigue crack growth test with constant stress amplitude by using carbon steel. Not only the overload level but also the cyclic stress condition affected the crack growth behavior after overloading. The effects of an overload on the rate of fatigue crack growth at constant amplitude have been of interest for some time, and much information has been gathered through which the crack growth was retarded. However there is relatively little information concerning the effects of an overload through which the crack growth was accelerated. Where the cyclic stress level was higher, the crack growth rate after overloading was kept higher level depending on the experimental conditions. Also, the acceleration of the crack growth was observed in some testing under plane stress conditions. Where the acceleration of crack growth was observed, the crack tips were blunted by applying overload. Thus the conditions of tensile overload affected zone were related to the acceleration of crack growth. It is discussed from the experimental results that the crack growth acceleration after overload was caused by the tensile residual stress developed in front of the crack tips due to applying compressive cyclic stress of which value exceeded a critical level.
- Published
- 2011
44. Preparation of magnesium ion conducting MgS–P2S5–MgI2 glasses by a mechanochemical technique
- Author
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Tomohiro Yamanaka, Masahiro Tatsumisago, Akihiro Yamauchi, and Akitoshi Hayashi
- Subjects
Materials science ,Inorganic chemistry ,General Chemistry ,Electrolyte ,Condensed Matter Physics ,Magnesium iodide ,Ion ,Crystal ,symbols.namesake ,chemistry.chemical_compound ,chemistry ,Electrical resistivity and conductivity ,symbols ,General Materials Science ,Raman spectroscopy ,Magnesium ion - Abstract
Using a mechanochemical technique in the composition range 0 ≤ x (mol.%) ≤ 30 and subsequent heat treatment, (100 − x)(0.6MgS·0.4P2S5) · xMgI2 glasses and glass-ceramics were prepared from 60MgS · 40P2S5 (mol.%) glass and MgI2 crystal. The effects of the addition of MgI2 on the structures and properties of the glass and glass-ceramic electrolytes were examined. The Raman spectra of all the glass-ceramics showed that the glass-ceramics included P2S64 − ions. The glass-ceramic having composition of x = 20 showed electrical conductivity of 2.1 × 10− 7 S cm− 1 at 200 °C.
- Published
- 2014
45. An Autopsy Case of Respiratory Failure due to Strongyloides Stercoralis Infection
- Author
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Akihiro Yamauchi, Takuya Kurimoto, Yuki Tanisaka, and Kousuke Sudo
- Subjects
Pediatrics ,medicine.medical_specialty ,Respiratory failure ,biology ,business.industry ,Medicine ,General Medicine ,Autopsy case ,business ,biology.organism_classification ,Strongyloides stercoralis - Published
- 2014
46. Artificial Intelligence-Assisted Polyp Detection for Colonoscopy: Initial Experience
- Author
-
Naoya Toyoshima, Toyoki Kudo, Kenichi Takeda, Fumio Ishida, Tomonari Cho, Yusuke Yagawa, Yuichi Mori, Holger R. Roth, Shin-ei Kudo, Yasuharu Maeda, Takemasa Hayashi, Akihiro Yamauchi, Hiroki Nakamura, Masashi Misawa, Shinichi Kataoka, Toshiyuki Baba, Masahiro Oda, Tomokazu Hisayuki, Hayato Itoh, Kensaku Mori, Noriyuki Ogata, Yushi Ogawa, Kunihiko Wakamura, and Katsuro Ichimasa
- Subjects
Adenoma ,Male ,medicine.medical_specialty ,Colon ,Computer science ,MEDLINE ,Colonic Polyps ,Colonoscopy ,Pilot Projects ,Image processing ,Video-Audio Media ,03 medical and health sciences ,0302 clinical medicine ,Artificial Intelligence ,Image Processing, Computer-Assisted ,medicine ,Humans ,Medical physics ,Aged ,Medical Errors ,Hepatology ,medicine.diagnostic_test ,Gastroenterology ,Middle Aged ,Computer aided detection ,030220 oncology & carcinogenesis ,Colonic Neoplasms ,Female ,030211 gastroenterology & hepatology - Published
- 2018
47. Effect of White Wheat Bread Containing Sugar Beet Fiber on Serum Lipids and Hepatic mRNA in Rats Fed on a Cholesterol-Free Diet
- Author
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Mizuki Kanazawa, Naoto Hashimoto, Mitsuo Sekikawa, Kyu-Ho Han, Kiyoshi Ohba, Michihiro Fukushima, Yumi Nakamura, Ken-ichiro Shimada, Akihiro Yamauchi, Ruvini Liyanage, and Setsuko Iijima
- Subjects
Dietary Fiber ,Male ,medicine.medical_treatment ,Blood lipids ,Biology ,Cholesterol 7 alpha-hydroxylase ,Applied Microbiology and Biotechnology ,Biochemistry ,Analytical Chemistry ,Steroid ,Cholesterol, Dietary ,chemistry.chemical_compound ,High-density lipoprotein ,medicine ,Animals ,RNA, Messenger ,Food science ,Cholesterol 7-alpha-Hydroxylase ,Molecular Biology ,Feces ,DNA Primers ,chemistry.chemical_classification ,Base Sequence ,Reverse Transcriptase Polymerase Chain Reaction ,Cholesterol ,Organic Chemistry ,food and beverages ,Fatty acid ,Bread ,General Medicine ,biology.organism_classification ,Lipids ,Rats, Inbred F344 ,Rats ,Liver ,chemistry ,lipids (amino acids, peptides, and proteins) ,Sugar beet ,Beta vulgaris ,Biotechnology - Abstract
We examined the effects of white wheat bread powder (BP) and white wheat bread powder containing sugar beet fiber (BBP) on serum cholesterol. The total cholesterol (-11%, -16%), HDL-cholesterol (-12%, -11%), non-HDL-cholesterol (-9%, -18%) and triacylglycerol (-44%, -58%) concentrations in the BP and BBP groups, respectively, were significantly different from those in the control group. The fecal excretion of neutral sterols in the BP and BBP groups and of acidic sterols in the BBP group was significantly higher than that in the control group. The hepatic cholesterol 7alpha-hydroxylase (CYP7A1) mRNA level in the BP and BBP groups was significantly higher than that in the control group. The cecal total short-chain fatty acid concentrations in the BBP group were significantly higher than those in the control group. These results indicate that the observed changes in serum lipid levels in the BP and BBP groups were due to the increased fecal lipid and CYP7A1 mRNA levels.
- Published
- 2009
48. Effects of Crack Opening Behavior on Crack Growth Rate after Overload
- Author
-
Akihiro Yamauchi, Tatsujiro Miyazaki, Chobin Makabe, and Anindito Purnowidodo
- Subjects
Crack closure ,Materials science ,Residual stress ,Effective stress ,mental disorders ,Ultimate tensile strength ,Fracture mechanics ,Composite material ,Paris' law ,Crack growth resistance curve ,Stress concentration - Abstract
It is well known that a single tensile overload applied during constant stress amplitude cycling at a positive stress ratio causes crack growth retardation. In the case of a negative stress ratio, however, the fatigue crack growth rate actually accelerated after a tensile overload. This crack growth behavior is related to the residual stress distribution and crack closure behavior. Therefore, the crack propagation rate before and after applying an overload can be evaluated by the effective stress intensity factor range. Where crack propagation was accelerated after applying an overload, blunted crack tips which occurred because of overload worked as sharp notch roots. The shape of the crack tip affected crack growth after overload in the case of negative stress ratio. In this study, it is found that acceleration of crack growth after overload is dependent on the crack opening behavior and loading conditions after overload.
- Published
- 2008
49. [Untitled]
- Author
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Miyuki Sugimori, Masahito Toyosaki, Miwa Sakakibara, Kenji Mizawa, Yasuhiro Ito, Takashi Isikawa, Akihiro Yamauchi, Masaru Ihira, Saori Ishida, Koji Watanabe, Akira Kaieda, Makoto Hibiya, Masaru Yamamoto, and Yoshinobu Hattori
- Subjects
medicine.medical_specialty ,Elution ,business.industry ,medicine ,Circulation (currency) ,business ,Cardiac surgery ,Surgery - Published
- 2007
50. Endocytoscopic narrow-band imaging efficiency for evaluation of inflammatory activity in ulcerative colitis
- Author
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Yuichi Mori, Shigeharu Hamatani, Masashi Misawa, Shin-ei Kudo, Yasuharu Maeda, Fuyuhiko Yamamura, Kunihiko Wakamura, Hideyuki Miyachi, Toyoki Kudo, Haruhiro Inoue, Noriyuki Ogata, Yoshiki Wada, Seiko Hayashi, Kazuo Ohtsuka, Akihiro Yamauchi, Fumio Ishida, and Takemasa Hayashi
- Subjects
Male ,medicine.medical_specialty ,Pathology ,Biopsy ,macromolecular substances ,Gastroenterology ,Severity of Illness Index ,Tertiary Care Centers ,Narrow Band Imaging ,Japan ,Retrospective Study ,Predictive Value of Tests ,Internal medicine ,medicine ,Humans ,Intestinal Mucosa ,Retrospective Studies ,Narrow-band imaging ,business.industry ,Rectum ,General Medicine ,Colonoscopy ,Middle Aged ,medicine.disease ,Ulcerative colitis ,digestive system diseases ,Capillaries ,Mucosal healing ,Colitis, Ulcerative ,Female ,business - Abstract
To assess the efficacy of endocytoscopic narrow-band imaging (EC-NBI) for evaluating the severity of inflammation in ulcerative colitis (UC).This retrospective study was conducted at a single tertiary care referral center. We included UC patients who underwent colonoscopy with endocytoscopy from July 2010 to December 2013. EC-NBI was performed, and the images were evaluated by assessing visibility, increased vascularization, and the increased calibers of capillaries and were classified as Obscure, Visible or Dilated. Obscure was indicative of inactive disease, while Visible and Dilated were indicative of acute inflammation. This study received Institutional Review Board approval. The primary outcome measures included the diagnostic ability of EC-NBI to distinguish between active and inactive UC on the basis of histological activity. The conventional endoscopic images were classified according to the Mayo endoscopic score. A score of 0 or 1 indicated inactive disease, whereas a score of 2 indicated active disease.Fifty-two patients were enrolled. There was a strong correlation between the EC-NBI findings and the histological assessment (r=0.871, P0.01). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of EC-NBI for diagnosing acute inflammation were 84.0%, 100%, 87.1%, 100%, and 92.3%, respectively, while those for the Mayo endoscopic score were 100%, 40.7%, 100%, 61.0%, and 69.2%, respectively. Compared with conventional endoscopy, EC-NBI was superior in diagnostic specificity, negative predictive value, and accuracy (P0.001, P=0.001 and P=0.047, respectively).The EC-NBI finding of capillaries in the rectal mucosa was strongly correlated with histological inflammation and aided in the differential diagnosis between active and inactive UC.
- Published
- 2015
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