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Search Results: 1 - 10 of 1112 matches for " Masaaki Iwata "
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Neural Activation by Milnacipran and Memory Extinction  [PDF]
Hisahito Ishida, Masaaki Iwata, Yukihiko Shirayama, Katsumasa Muneoka
Journal of Behavioral and Brain Science (JBBS) , 2012, DOI: 10.4236/jbbs.2012.22016
Abstract: Background: Among neurotransmitter influencing memory formation, the noradrenergic system has been recognized as an important system. Memory formation involves various regions including the prefrontal cortex, hippocampus, amygdala and septum. Method: We investigated the effects of milnacipran on passive avoidance task and evaluated Fos counting in the prefrontal cortex, hippocampus, septum, amygdala and nucleus accumbens. Results: The milnacipran-treated rats (20 mg/kg, 4 days) showed a significant decrease in the number of Fos-immunoreactive cells in the infralimbic portion of prefrontal cortex, the shell portion of nucleus accumbens and the CA1 region of hippocampus, but a significant increase in the Fos counts in the lateral septum with no changes in the Fos counts in the striatum and amygdala. The milnacipran-treated rats showed amelioration in memory extinction (although not statistically significant), but not in memory acquisition and consolidation in the passive avoidance test. Conclusion: The differential activation of the brain regions might be possible sites for ameliorating memory extinction as well as antidepressant effects.
Intratympanic injection of dexamethasone for treatment of tinnitus in patients with sudden sensorineural hearing loss
Tadao Yoshida,Masaaki Teranishi,Tomoyuki Iwata,Hironao Otake
Audiology Research , 2012, DOI: 10.4081/audiores.2012.e2
Abstract: The purpose of this study is to test the effectiveness of intratympanic dexamethasone injections as a treatment for severe tinnitus in idiopathic sudden sensorineural hearing loss (SNHL). We studied 37 patients who received intratympanic dexamethasone injections and 14 control patients who did not receive it, with severe tinnitus after onset of unilateral sudden SNHL. Hearing level did not change during this study in any patient. The relationship between the duration of tinnitus and effectiveness of treatment was investigated in sudden SNHL. We used a visual analogue scale to evaluate 51 patients with severe tinnitus at the stage of stable hearing level after idiopathic sudden sensorineural hearing loss. Forty-one per cent of patients showed significant improvement after treatment. The average period between onset of sudden sensorineural hearing loss and initiation of intratympanic dexamethasone injection was significantly shorter (207 days) in the improved group than in the unchanged group (482 days) (P<0.001). In control group, one of 14 patients presented significant improvement spontaneously. Intratympanic dexamethasone treatment may be effective in treatment of severe tinnitus after sudden SNHL at the stage of stable hearing level, and the shorter the period from onset of sudden deafness to the start of intratympanic dexamethasone treatment, the greater the improvement in tinnitus that can be expected.
Zero Sound Propagation in Femto-Scale Quantum Liquids  [PDF]
Yoritaka Iwata
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.36064
Abstract: Charge equilibration has been recognized as a dominant process at the early stage of low-energy heavy-ion reactions. The production of exotic nuclei is suppressed under the appearance of charge equilibration, in which the proton-neutron ratios of the final reaction products are inevitably averaged. Therefore charge equilibration plays one of the most crucial roles in the synthesis of chemical elements. Focusing on how and when the charge equilibration takes place, zero sound propagation in femto-scale quantum liquids is explained.
Alternative Infinitesimal Generator of Invertible Evolution Families  [PDF]
Yoritaka Iwata
Journal of Applied Mathematics and Physics (JAMP) , 2017, DOI: 10.4236/jamp.2017.54071
A logarithm representation of evolution operators is defined. Generators of invertible evolution families are characterized by the logarithm representation. In this article, using the logarithm representation, a concept of evolution operators without satisfying the semigroup property is introduced. In conclusion the existence of alternative infinitesimal generator is clarified.
Influence of dietary iodine deficiency on the thyroid gland in Slc26a4-null mutant mice
Tomoyuki Iwata, Tadao Yoshida, Masaaki Teranishi, Yoshiharu Murata, Yoshitaka Hayashi, Yasuhiko Kanou, Andrew J Griffith, Tsutomu Nakashima
Thyroid Research , 2011, DOI: 10.1186/1756-6614-4-10
Abstract: We evaluated the thyroid volume in histological sections with the use of three-dimensional reconstitution software, we measured serum levels of total tri-iodothyronine (TT3) and total thyroxine (TT4) levels, and we studied the thyroid gland morphology by transmission electron microscopy.TT4 levels became low but TT3 levels did not change significantly after eight weeks of an iodine-deficient diet compared to levels in the control diet animals. Even in Slc26a4-null mice fed an iodine-deficient diet, the volume of the thyroid gland did not increase although the size of each epithelial cell increased with a concomitant decrease of thyroid colloidal area.An iodine-deficient diet did not induce goiter in Slc26a4-null mice, suggesting that other environmental, epigenetic or genetic factors are involved in goiter development in PDS.Pendred syndrome (PDS) is an autosomal recessive disorder characterized by sensorineural hearing impairment, presence of goiter, and a partial defect in iodine organification [1]. The goiter in PDS is variable in its presentation; it can develop at any age (although generally after puberty), but may be totally absent in some affected individuals [2]. Also, there is substantial intrafamilial and regional variation, and nutritional iodine intake may be a significant modifier of the thyroid phenotype [1]. Kopp et al. suggested that under conditions of sufficient iodine intake, thyroid enlargement may be very mild or absent, and hence these patients are often simply categorized as having enlarged vestibular aqueduct [1]. Sato et al. also suggested that even in patients with impaired iodide transport, high iodine intake may prevent the development of goiter [3].Slc26a4-null (Slc26a4-/-) mutant mice were generated by Everett et al. [2]. Slc26a4-/- mice are profoundly deaf with vestibular dysfunction, but they lack goiter and thyroid histological abnormalities. We hypothesized that the absence of goiter and hypothyroidism in Slc26a4-/- mice was due to
Adaptive Parallel Particle Swarm Optimization Algorithm Based on Dynamic Exchange of Control Parameters  [PDF]
Masaaki Suzuki
American Journal of Operations Research (AJOR) , 2016, DOI: 10.4236/ajor.2016.65037
Abstract: Updating the velocity in particle swarm optimization (PSO) consists of three terms: the inertia term, the cognitive term and the social term. The balance of these terms determines the balance of the global and local search abilities, and therefore the performance of PSO. In this work, an adaptive parallel PSO algorithm, which is based on the dynamic exchange of control parameters between adjacent swarms, has been developed. The proposed PSO algorithm enables us to adaptively optimize inertia factors, learning factors and swarm activity. By performing simulations of a search for the global minimum of a benchmark multimodal function, we have found that the proposed PSO successfully provides appropriate control parameter values, and thus good global optimization performance.
A Study on Flow Structure around a Bridge Beam and Behavior of Sea Water Mist  [PDF]
Masaaki Ishikawa
Open Journal of Fluid Dynamics (OJFD) , 2017, DOI: 10.4236/ojfd.2017.73022
Abstract: Okinawa in the subtropical islands enclosed in the ocean has a problem that corrosion of structures progresses quickly because of high temperature, high humidity and adhesion of sea-water mists flying from sea. Author is interested in corrosion of bridge made of weatherability steel. Therefore, it needs to investigate the flow structure around bridge beams and behavior of sea-water mist (droplet). In this paper, flow visualization and PIV are attempted to understand the flow structures around bridge beams and, furthermore, numerical approach of motion of droplets is attempted to understand the collision of sea-water mists on the bridge wall.
Replication of Epstein-Barr Virus Primary Infection in Human Tonsil Tissue Explants
Kensei Gotoh, Yoshinori Ito, Seiji Maruo, Kenzo Takada, Terukazu Mizuno, Masaaki Teranishi, Seiichi Nakata, Tsutomu Nakashima, Seiko Iwata, Fumi Goshima, Shigeo Nakamura, Hiroshi Kimura
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0025490
Abstract: Epstein-Barr virus (EBV) may cause a variety of virus-associated diseases, but no antiviral agents have yet been developed against this virus. Animal models are thus indispensable for the pathological analysis of EBV-related infections and the elucidation of therapeutic methods. To establish a model system for the study of EBV infection, we tested the ability of B95–8 virus and recombinant EBV expressing enhanced green fluorescent protein (EGFP) to replicate in human lymphoid tissue. Human tonsil tissues that had been surgically removed during routine tonsillectomy were sectioned into small blocks and placed on top of collagen sponge gels in culture medium at the air-interface, then a cell-free viral suspension was directly applied to the top of each tissue block. Increasing levels of EBV DNA in culture medium were observed after 12–15 days through 24 days post-infection in tissue models infected with B95–8 and EGFP-EBV. Expression levels of eight EBV-associated genes in cells collected from culture medium were increased during culture. EBV-encoded small RNA-positive cells were detected in the interfollicular areas in paraffin-embedded sections. Flow cytometric analyses revealed that most EGFP+ cells were CD3? CD56? CD19+ HLA-DR+, and represented both na?ve (immunoglobulin D+) and memory (CD27+) B cells. Moreover, EBV replication in this model was suppressed by acyclovir treatment in a dose-dependent manner. These data suggest that this model has potential for use in the pathological analysis of local tissues at the time of primary infection, as well as for screening novel antiviral agents.
Selenoprotein S (SEPS1) gene -105G>A promoter polymorphism influences the susceptibility to gastric cancer in the Japanese population
Tomoyuki Shibata, Tomiyasu Arisawa, Tomomitsu Tahara, Masaaki Ohkubo, Daisuke Yoshioka, Naoko Maruyama, Hiroshi Fujita, Yoshio Kamiya, Masakatsu Nakamura, Mitsuo Nagasaka, Masami Iwata, Kazuya Takahama, Makoto Watanabe, Ichiro Hirata
BMC Gastroenterology , 2009, DOI: 10.1186/1471-230x-9-2
Abstract: We took stomach biopsies during endoscopies of 268 Japanese gastric cancer patients (193 males and 75 females, average age 65.3), and 306 control patients (184 males and 122 females, average age 62.7) and extracted the DNA from the biopsy specimens. All subjects provided written informed consent. For the genotyping of the SEPS1 promoter polymorphism at position -105G>A, PCR-RFLP methods were used and the PCR products were digested with PspGI.Logistic-regression analysis was used to estimate odds ratios (OR) and 95% confidence intervals (CI), adjusting for age, sex, and H. pylori infection status.Among cases, the distribution of genotypes was as follows: 88.4% were GG, 11.2% were GA, and 0.4% were AA. Among controls, the distribution was as follows: 92.5% were GG, 7.2% were GA, and 0.3% were AA. Among males, carrying the A allele was associated with an increased odds of gastric cancer, compared with the GG genotype (OR: 2.0, 95% CI 1.0–4.1, p = 0.07). Compared with the GG genotype, carrying the A allele was significantly associated with increased risks of intestinal type gastric cancer (OR: 2.0, 95%CI 1.0–3.9, p < 0.05) as well as of gastric cancer located in the middle third of the stomach (OR: 2.0, 95%CI 1.0–3.9, p < 0.05).The -105G>A promoter polymorphism of SEPS1 was associated with the intestinal type of gastric cancer. This polymorphism may influence the inflammatory conditions of gastric mucosa. Larger population-based studies are needed for clarifying the relation between inflammatory responses and SEPS1 polymorphism.Gastric cancer remains a considerable public health problem worldwide. Although the incidence and mortality rates of gastric cancer have decreased gradually, gastric cancer is second only to lung cancer as the leading cause of cancer death around the world [1,2]. Helicobacter pylori (H. pylori) was designated as a causative pathogen for gastric carcinogenesis[3]. Inflammation may be a key factor in the process of carcinogenesis from chronic gastr
Involvement of ERK Phosphorylation of Trigeminal Spinal Subnucleus Caudalis Neurons in Thermal Hypersensitivity in Rats with Infraorbital Nerve Injury
Ikuko Suzuki, Yoshiyuki Tsuboi, Masamichi Shinoda, Kazuo Shibuta, Kuniya Honda, Ayano Katagiri, Masaaki Kiyomoto, Barry J. Sessle, Shingo Matsuura, Kinuyo Ohara, Kentaro Urata, Koichi Iwata
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0057278
Abstract: To evaluate the involvement of the mitogen-activated protein kinase (MAPK) cascade in orofacial neuropathic pain mechanisms, this study assessed nocifensive behavior evoked by mechanical or thermal stimulation of the whisker pad skin, phosphorylation of extracellular signal-regulated kinase (ERK) in trigeminal spinal subnucleus caudalis (Vc) neurons, and Vc neuronal responses to mechanical or thermal stimulation of the whisker pad skin in rats with the chronic constriction nerve injury of the infraorbital nerve (ION-CCI). The mechanical and thermal nocifensive behavior was significantly enhanced on the side ipsilateral to the ION-CCI compared to the contralateral whisker pad or sham rats. ION-CCI rats had an increased number of phosphorylated ERK immunoreactive (pERK-IR) cells which also manifested NeuN-IR but not GFAP-IR and Iba1-IR, and were significantly more in ION-CCI rats compared with sham rats following noxious but not non-noxious mechanical stimulation. After intrathecal administration of the MEK1 inhibitor PD98059 in ION-CCI rats, the number of pERK-IR cells after noxious stimulation and the enhanced thermal nocifensive behavior but not the mechanical nocifensive behavior were significantly reduced in ION-CCI rats. The enhanced background activities, afterdischarges and responses of wide dynamic range neurons to noxious mechanical and thermal stimulation in ION-CCI rats were significantly depressed following i.t. administration of PD98059, whereas responses to non-noxious mechanical and thermal stimulation were not altered. The present findings suggest that pERK-IR neurons in the Vc play a pivotal role in the development of thermal hypersensitivity in the face following trigeminal nerve injury.
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