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Search Results: 1 - 10 of 852 matches for " Yoshinobu Kubota "
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Molecular targeting therapy with angiotensin II receptor blocker for prostatic cancer
Hiroji Uemura,Hitoshi Ishiguro,Yoshinobu Kubota
Oncology Reviews , 2011, DOI: 10.4081/135
Abstract: Angiotensin II (Ang-II) plays a key role as a vasoconstrictor in controlling blood pressure and electrolyte/fluid homeostasis. Recently it has also been shown that this peptide is a cytokine, acting as a growth factor in cardiovascular and stromal cells. In addition, the physiological function of Ang-II seems to be similar in prostate cancer and stromal cells. It is widely assumed that Ang-II facilitates the growth of both cells, and its receptor blockers (ARBs) have the potential to inhibit the growth of various cancer cells and tumors through the Ang-II receptor type 1 (AT1 receptor). The mechanism of cell growth inhibition by ARBs has been considered to be that of suppression of the signal transduction systems activated by growth factors or cytokines in prostate cancer cells, and suppression of angiogenesis. This review highlights the possible use of ARBs as novel agents for prostatic diseases including prostate cancer and benign hypertrophy, and covers related literature.
Synergistic Antibacterial Performance of a Cu/WO3-Added PTFE Particulate Superhydrophobic Composite under Visible-Light Exposure  [PDF]
Yanyan Yao, Kentaro Yamauchi, Goro Yamauchi, Tsuyoshi Ochiai, Taketoshi Murakami, Yoshinobu Kubota
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2012, DOI: 10.4236/jbnb.2012.34042
Abstract: Addition of TiO2 to a polytetrafluoroethylene (PTFE) particle-dispersed composite contributes to the self-cleaning properties of the water-repellent composite. However, its application is limited to outdoor usage or under ultraviolet (UV) irradiation. In this study, a novel visible-light-sensitive photocatalytic and superhydrophobic material was developed by adding Cu/WO3 to a PTFE particulate composite material to overcome this deficit. A remarkable property of this novel composite material is the synergistic antibacterial performance against Escherichia coli (E. coli), Staphylo-coccus aureus, and methicillin-resistant Staphylococcus aureus compared with the addition of Cu/WO3 without PTFE particles material. During 24-h exposure in visible light at 2000 lx, the number of viable cells of the three strains on the surface of the 8wt% Cu/WO3-added PTFE particulate composite decreased from 2 – 4 × 105 colony-formation units (CFUs) to less than 10, the limit of detection. This bactericidal rate is four times higher than that of 8wt% Cu/WO3 without PTFE particles material, which is attributed to the air trapped in the rough surface of the novel material providing additional oxygen to the photocatalytic reaction. Even for exposure to visible light at 100 lx, the decrease in CFUs of E. coli on the 12wt% Cu/WO3-added PTFE particulate composite reached nearly 2.0 logs. The characterization of the Cu/WO3-added PTFE particulate composite indicated that the composite material containing 80wt% PTFE maintained a superhydrophobic or water-repellent property with a water contact angle >150, although the Cu/WO3 in the composite material remained hydrophilic under visible light. The Cu/WO3-added PTFE particulate composite displayed photo-catalytic reactions to decompose oleic acid adsorbed on its surface and gaseous acetaldehyde under UV-A and visible-light illumination. All results demonstrate that the Cu/WO3-added PTFE particulate composite material may be used in sterilization, as a water repellent, for self-cleaning, and in the oxidative decomposition of volatile organic compounds (VOC) both indoors and outdoors.
Magnetization switching by current and microwaves
Tomohiro Taniguchi,Daisuke Saida,Yoshinobu Nakatani,Hitoshi Kubota
Physics , 2015,
Abstract: We propose a theoretical model of magnetization switching in a ferromagnetic multilayer by both electric current and microwaves. The electric current gives a spin transfer torque on the magnetization, while the microwave induces a precession of the magnetization around the initial state. Based on numerical simulation of the Landau-Lifshitz-Gilbert (LLG) equation, it is found that the switching current is reduced by less than a half compared with the switching caused solely by the spin transfer torque when the microwave frequency is in a certain range. We develop a theory of switching from the LLG equation averaged over a constant energy curve. It was found that the switching current should be classified into four regions, depending on the values of the microwave frequency. Based on the analysis, we derive an analytical formula of the optimized frequency minimizing the switching current, which is smaller than the ferromagnetic resonance frequency. We also derive an analytical formula of the minimized switching current. Both the optimized frequency and the minimized switching current decreases with increasing the amplitude of the microwave field. The results will be useful to achieve high thermal stability and low switching current in spin torque system simultaneously.
On Quaternionic 3 CR-Structure and Pseudo-Riemannian Metric  [PDF]
Yoshinobu Kamishima
Applied Mathematics (AM) , 2018, DOI: 10.4236/am.2018.92008
Abstract:
A CR-structure on a 2n +1-manifold gives a conformal class of Lorentz metrics on the Fefferman S1-bundle. This analogy is carried out to the quarternionic conformal 3-CR structure (a generalization of quaternionic CR- structure) on a 4n + 3 -manifold M. This structure produces a conformal class [g] of a pseudo-Riemannian metric g of type (4n + 3,3) on M × S3. Let (PSp(n +1,1), S4n+3) be the geometric model obtained from the projective boundary of the complete simply connected quaternionic hyperbolic manifold. We shall prove that M is locally modeled on (PSp(n +1,1), S4n+3) if and only if (M × S3 ,[g]) is conformally flat (i.e. the Weyl conformal curvature tensor vanishes).
Antibacterial Activity of Hydrophobic Composite Materials Containing a Visible-Light-Sensitive Photocatalyst
Kentaro Yamauchi,Yanyan Yao,Tsuyoshi Ochiai,Munetoshi Sakai,Yoshinobu Kubota,Goro Yamauchi
Journal of Nanotechnology , 2011, DOI: 10.1155/2011/380979
Abstract: The conventional superhydrophobic surface offered by PTFE provides no sterilization performance and is not sufficiently repellent against organic liquids. These limit PTFE's application in the field of disinfection and result a lack of durability. N-doped TiO2 photocatalyst added PTFE composite material was developed to remedy these shortcomings. This paper reports the surface characteristics, and the bactericidal and self-cleaning performance of the newly-developed composite material. The material exhibited a contact angle exceeding 150 degrees consistent with its hydrophobicity despite the inclusion of the hydrophilic N-doped TiO2. The surface free energy obtained for this composite was 5.8?mN/m. Even when exposed to a weak fluorescent light intensity (100 lx) for 24 hours, the viable cells of gram-negative E. coli on the 12% N-doped TiO2-PTFE film were reduced 5 logs. The higher bactericidal activity was also confirmed on the gram-positive MRSA. Compared with the N-doped TiO2 coating only, the inactivation rate of the composite material was significantly enhanced. Utilizing the N-doped TiO2 with the PTFE composite coating could successfully remove, by UV illumination, oleic acid adsorbed on its surface. These results demonstrate the potential applicability of the novel N-doped TiO2 photocatalyst hydrophobic composite material for both indoor antibacterial action and outdoor contamination prevention. 1. Introduction It is well known that the conventional superhydrophobic surface offered by polytetrafluoroethylene (PTFE) provides no sterilization performance and is not sufficiently repellent against organic matters. Thus, there is potential risk for bacteria to adhere to its surface more readily in ambient air, as well as organic matters is considered to reduce the durability of the superhydrophobic performance. To remedy this shortcoming, anatase titanium dioxide (TiO2), a UV light-sensitive photocatalyst added water repellent composite material has been developed in our previous study [1–5]. TiO2 was used to demonstrate the inactivation of various bacteria, such as Escherichia coli (E. coli), methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa (P. aeruginosa), Legionella pneumophila (L. pneumophila) [6–8], and Clostridium difficile spores [8]. The inclusion of TiO2 to the PTFE coating is expected to generate antimicrobial and self-cleaning properties, which would expand its scope of application. Anatase TiO2-added PTFE composite material is not only water-repellent but also exhibits self-cleaning properties. However, because
Ureteroscopy-Assisted Retrograde Nephrostomy (UARN) after Anatrophic Nephrolithotomy
Takashi Kawahara,Hiroki Ito,Hideyuki Terao,Yoshitake Kato,Takehiko Ogawa,Hiroji Uemura,Yoshinobu Kubota,Junichi Matsuzaki
Case Reports in Medicine , 2012, DOI: 10.1155/2012/164963
Abstract: Introduction. Open surgical anatrophic nephrolithotomy (ANL) had been the standard treatment for large renal calculi prior to the development of endoscopic devices and endoscopic techniques. A previous report described the efficacy of ureteroscopy-assisted retrograde nephrostomy (UARN) and presented a case of renal calculi successfully treated with UARN during percutaneous nephrolithotomy (PCNL) in a patient after ANL. Case Presentation. A 61-year-old male with left renal calculi was referred for further treatment. The patient was placed under general and epidural anesthesia, in a Galdakao-modified Valdivia position. A flexible ureteroscope (URS) was inserted, and a Lawson retrograde nephrostomy puncture wire was advanced into the flexible URS. The puncture wire then followed the route from the renal pelvis to the exit skin. Calculus fragmentation was undertaken using a pneumatic lithotripter. Conclusions. UARN for PCNL was therefore found to be a safe, effective, and appropriate treatment for a patient presenting with renal calculi after undergoing ANL.
Encrusted Ureteral Stent Retrieval Using Flexible Ureteroscopy with a Ho: YAG Laser
Takashi Kawahara,Hiroki Ito,Hideyuki Terao,Takehiko Ogawa,Hiroji Uemura,Yoshinobu Kubota,Junichi Matsuzaki
Case Reports in Medicine , 2012, DOI: 10.1155/2012/862539
Abstract: A 23-year-old female had bilateral ureteral stents placed due to bilateral renal stones and hydronephrosis. The bilateral ureteral stents were changed every 3 months. A kidney ureter bladder (KUB) film showed left encrustation along the ureteral stent thus necessitating removal; however, the ureteral stent could not be removed cystoscopically. The ureteral stent was, therefore, extracted using flexible ureteroscopy (URS) with a holmium (Ho): yttrium aluminum garnet (YAG) laser.
Ureteral Stent Retrieval Using the Crochet Hook Technique in Females
Takashi Kawahara, Hiroki Ito, Hideyuki Terao, Takuya Yamagishi, Takehiko Ogawa, Hiroji Uemura, Yoshinobu Kubota, Junichi Matsuzaki
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0029292
Abstract: Introduction We developed a method for ureteral stent removal in female patients that requires no cystoscopy or fluoroscopic guidance using a crochet hook. In addition, we also investigated the success rate, complications and pain associated with this procedure. Methods A total of 40 female patients (56 stents) underwent the removal of ureteral stents. All procedures were carried out with the patients either under anesthesia, conscious sedation, or analgesic suppositories as deemed appropriate for each procedure including Shock Wave Lithotripsy (SWL), Ureteroscopy (URS), Percutaneous Nephrolithotomy (PCNL), and ureteral stent removal. At the time of these procedures, fluoroscopy and/or cystoscopy were prepared, but they were not used unless we failed to successfully remove the ureteral stent using the crochet hook. In addition, matched controls (comprising 50 stents) which were removed by standard ureteral stent removal using cystoscopy were used for comparison purposes. Results A total of 47 of the 56 stents (83.9%) were successfully removed. In addition, 47 of 52 (90.4%) were successfully removed except for two migrated stents and two heavily encrusted stents which could not be removed using cystoscopy. Ureteral stent removal using the crochet hook technique was unsuccessful in nine patients, including two encrustations and two migrations. Concerning pain, ureteral stent removal using the crochet hook technique showed a lower visual analogue pain scale (VAPS) score than for the standard technique using cystoscopy. Conclusions Ureteral stent removal using a crochet hook is considered to be easy, safe, and cost effective. This technique is also easy to learn and is therefore considered to be suitable for use on an outpatient basis.
C57BL/KsJ-db/db-ApcMin/+ Mice Exhibit an Increased Incidence of Intestinal Neoplasms
Kazuya Hata,Masaya Kubota,Masahito Shimizu,Hisataka Moriwaki,Toshiya Kuno,Takuji Tanaka,Akira Hara,Yoshinobu Hirose
International Journal of Molecular Sciences , 2011, DOI: 10.3390/ijms12118133
Abstract: The numbers of obese people and diabetic patients are ever increasing. Obesity and diabetes are high-risk conditions for chronic diseases, including certain types of cancer, such as colorectal cancer (CRC). The aim of this study was to develop a novel animal model in order to clarify the pathobiology of CRC development in obese and diabetic patients. We developed an animal model of obesity and colorectal cancer by breeding the C57BL/KsJ- db /db (db/db) mouse, an animal model of obesity and type II diabetes, and the C57BL/6J- ApcMin/+ (Min/+) mouse, a model of familial adenomatous polyposis. At 15 weeks of age, the N9 backcross generation of C57BL/KsJ- db /db- ApcMin/+ (db/db-Min/+) mice developed an increased incidence and multiplicity of adenomas in the intestinal tract when compared to the db/m-Min/+ and m/m-Min/+ mice. Blood biochemical profile showed significant increases in insulin (8.3-fold to 11.7-fold), cholesterol (1.2-fold to 1.7-fold), and triglyceride (1.2-fold to 1.3-fold) in the db/db-Min/+ mice, when compared to those of the db/m-Min/+ and m/m-Min/+ mice. Increases (1.4-fold to 2.6-fold) in RNA levels of insulin-like growth factor (IGF)-1, IRF-1R, and IGF-2 were also observed in the db/db-Min/+ mice. These results suggested that the IGFs, as well as hyperlipidemia and hyperinsulinemia, promoted adenoma formation in the db/db-Min/+ mice. Our results thus suggested that the db/db-Min/+ mice should be invaluable for studies on the pathogenesis of CRC in obese and diabetes patients and the therapy and prevention of CRC in these patients.
Ureteroscopy-assisted retrograde nephrostomy for lower calyx calculi in horseshoe kidney: two case reports
Takashi Kawahara, Hiroki Ito, Hideyuki Terao, Katsuyuki Tanaka, Takehiko Ogawa, Hiroji Uemura, Yoshinobu Kubota, Junichi Matsuzaki
Journal of Medical Case Reports , 2012, DOI: 10.1186/1752-1947-6-194
Abstract: Case 1 was a 68-year-old man who was shown on radiography to have left lower calyx calculi (19?×?15mm, 7?×?5mm, and 7?×?3mm) in horseshoe kidney. Case 2 was a 36-year-old woman shown on radiography to have a left lower calyx calculus (10?×?8mm) in horseshoe kidney.Both patients were stone-free after ureteroscopy-assisted retrograde nephrostomy during percutaneous nephrolithotomy. Ureteroscopy-assisted retrograde nephrostomy is a promising procedure for safely and effectively treating lower calyx stones in horseshoe kidney.
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