15 results on '"Ayaka Yokoyama"'
Search Results
2. A SIMPLE EVALUATION OF THE WALL AND COLUMN WALL RATIOS OF LOW-RISE RC BUILDINGS BASED ON ENERGY BALANCE FOR CONTINUED USE AFTER EARTHQUAKES
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Taisuke MURAKI, Takuma HASHIMOTO, Tadashi TAMURA, Misaki YOKOJI, Ayaka YOKOYAMA, Shigenobu MORI, and Kazuya OHTA
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- 2023
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3. Rovatirelin ameliorates motor dysfunction in the cytosine arabinoside‐induced rat model of spinocerebellar degeneration via acetylcholine and dopamine neurotransmission
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Tomoyuki, Ijiro, Atsushi, Yaguchi, Ayaka, Yokoyama, and Sumiyoshi, Kiguchi
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Male ,Pharmacology ,Pyrrolidines ,Physiology ,Dopamine ,Cytarabine ,Synaptic Transmission ,Acetylcholine ,Rats ,Mice ,Physiology (medical) ,Animals ,Ataxia ,Female ,Thyrotropin-Releasing Hormone ,Oxazolidinones ,Spinocerebellar Degenerations - Abstract
Thyrotropin-releasing hormone (TRH) and the TRH mimetic taltirelin have been used in Japan for the treatment of spinocerebellar degeneration (SCD), a type of progressive ataxia. A TRH mimetic, rovatirelin, ameliorates ataxia symptoms in the rolling mouse Nagoya, a hereditary SCD model. The aim of this study was to verify the effects of oral administration of rovatirelin on a cytosine arabinoside (Ara-C)-induced ataxia rat model, a sporadic SCD model characterized by gait abnormalities and falls because of cerebellar atrophy and investigate the central nervous system mechanism associated with rovatirelin-mediated amelioration of motor dysfunction in these rats. Rovatirelin at ≥3 mg/kg significantly decreased the fall index, which is a primary endpoint of improved motor function calculated by dividing the number of falls by the locomotor activity, in both male and female rats with Ara-C-induced ataxia. Furthermore, rovatirelin caused a significant increase in locomotor activity in a dose-dependent manner. Taltirelin at ≥30 mg/kg ameliorated motor dysfunction in ataxic rats. Moreover, rovatirelin significantly increased acetylcholine (ACh) levels in the medial prefrontal cortex (mPFC) and dopamine (DA) levels in the nucleus accumbens (NAc) at ≥3 mg/kg and significantly increased DA levels in the dorsal striatum at ≥10 mg/kg in normal rats. In conclusion, oral administration of rovatirelin ameliorates motor dysfunction in rats with Ara-C-induced ataxia, owing to its ACh-increasing effects in the mPFC and DA-increasing effects in the dorsal striatum and NAc. Furthermore, the effects of rovatirelin were more potent than those of taltirelin.
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- 2022
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4. Real-Time Hybrid Test Using Two-Individual Actuators to Evaluate Seismic Performance of RC Frame Model Controlled by AMD
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Hideo Fujitani, Kohiro Fushihara, Ayaka Yokoyama, Yoichi Mukai, and Takashi Fujinaga
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time delay compensator ,Computer science ,reinforced concrete structure ,Geography, Planning and Development ,0211 other engineering and technologies ,PID controller ,020101 civil engineering ,02 engineering and technology ,Column (database) ,Synchronization ,0201 civil engineering ,lcsh:HT165.5-169.9 ,active mass damper ,021110 strategic, defence & security studies ,Computer simulation ,business.industry ,Building and Construction ,Structural engineering ,lcsh:City planning ,hydraulic actuator ,Urban Studies ,Hydraulic cylinder ,lcsh:TA1-2040 ,shaking table ,Earthquake shaking table ,real-time hybrid simulation ,Restoring force ,business ,Actuator ,lcsh:Engineering (General). Civil engineering (General) - Abstract
The seismic responses of a single-story reinforced concrete (RC) frame building model under control using an active mass damper (AMD) are demonstrated through a real-time hybrid simulation (RTHS) method. In this study, the RTHS test is carried out by using a hydraulic actuator and a shaking table under synchronization. Most parts of the target RC frame model are provided as an analytical model for an online computer simulation, and only the single column of the first story is prepared as an experimental substructure. A hydraulic actuator deforms the actual RC column, and uncertainty or nonlinearity of the RC column's behavior is focused on in this RTHS test. At the same time, a control device of AMD is actually tested under a situation of installing it on the target building's floor. The floor response of the target building model is generated using a shaking table. A control motion of the AMD is manipulated based on an online simulation of the entire RC building model. Firstly, a time delay compensation of the hydraulic actuator is considered. Time delay parameters are identified using a combination model of a time lag and a first-order delay. A PID controller and a time series compensator are applied to improve actuator performances. Next, the reproducibility of the RTHS test using two-individual actuators is evaluated. The tracking of a restoring force and deformation of the actual RC column specimen generated by the hydraulic actuator and floor motion responses reproduced on the shaking table are investigated. To improve the online numerical simulation based on the measured force responses of the RC column specimen, a high-pass filter (HPF) is applied for a force correction to utilize its phase-lead property. The effect of this HPF force correction is evaluated in both a linear region and a strong nonlinear region of the actual RC column specimen. Finally, the RTHS test results are compared to fully numerical simulations and the control effect of the AMD to increase the damping effect for the target RC building model is also investigated.
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- 2020
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5. Impact of Inter-fractional Anatomical Changes on Dose Distributions in Passive Carbon-Ion Radiotherapy for Prostate Cancer: Comparison of Vertical and Horizontal Fields
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Yoshiki Kubota, Takashi Nakano, Hidemasa Kawamura, Takayuki Sutou, Satoshi Abe, Nobuteru Kubo, Hiro Sato, Kazuhisa Tsuda, Tatsuya Ohno, Yuhei Miyasaka, and Ayaka Yokoyama
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0301 basic medicine ,Cancer Research ,adequate margin ,Horizontal and vertical ,Field (physics) ,carbon-ion radiotherapy ,lcsh:RC254-282 ,Standard deviation ,03 medical and health sciences ,0302 clinical medicine ,Prostate ,medicine ,Radiation treatment planning ,Original Research ,Mathematics ,Reproducibility ,business.industry ,Sigmoid function ,patient positioning ,prostate cancer ,lcsh:Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,030104 developmental biology ,medicine.anatomical_structure ,Oncology ,030220 oncology & carcinogenesis ,inter-fractional anatomical change ,Nuclear medicine ,business ,Beam (structure) - Abstract
Purpose: We quantified the inter-fractional changes associated with passive carbon-ion radiotherapy using vertical and horizontal beam fields for prostate cancer. Methods: In total, 118 treatment-room computed tomography (TRCT) image sets were acquired from 10 patients. Vertical (anterior–posterior) and horizontal (left–right) fields were generated on the planning target volume identified by treatment planning CT. The dose distribution for each field was recalculated on each TRCT image set at the bone-matching position and evaluated using the dose–volume parameters for the prostate and rectum V95 values. To confirm adequate margins, we generated vertical and horizontal fields with 0-, 2-, 4-, and 6-mm isotropic margins from the prostate and recalculated the dose distributions on all TRCT image sets. Sigmoid functions were fitted to a plot of acceptable ratios (that is, when prostate V95 > 98%) vs. the isotropic margin size to identify the margin at which this ratio was achieved in 95% of patients with a vertical or horizontal field. Results: The prostate V95 values (mean ± standard deviation) were 99.89 ± 0.62% and 99.99 ± 0.00% with vertical and horizontal fields, respectively; this difference was not statistically significant (p = 0.067). The rectum V95 values were 1.93 ± 1.25 and 1.88 ± 0.96 ml with vertical and horizontal fields, respectively; the difference was not statistically significant (p = 0.432). The estimated adequate margins were 2.2 and 3.0 mm for vertical and horizontal fields, respectively. Conclusions: Although there is no significant difference, horizontal fields offer higher reproducibility for prostate dosing than vertical fields in our clinical setting, and 3.0 mm was found to be an adequate margin for inter-fractional changes.
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- 2020
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6. Comparison of the Effects of Mitiglinide and Glibenclamide Administered in Combination with the Dipeptidyl Peptidase-IV Inhibitor Sitagliptin in Rats with Streptozotocin-Nicotinamide-Induced Type 2 Diabetes
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Mamoru Kobayashi, Toshihiro Inoue, Sumiyoshi Kiguchi, Ayaka Yokoyama, Satoshi Tatemichi, Kazuma Ojima, Kenji Akahane, and Hiroo Takeda
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Blood Glucose ,Male ,medicine.medical_specialty ,030209 endocrinology & metabolism ,Type 2 diabetes ,Isoindoles ,Pharmacology ,Hypoglycemia ,Dipeptidyl peptidase ,Diabetes Mellitus, Experimental ,Sitagliptin Phosphate ,Glibenclamide ,03 medical and health sciences ,0302 clinical medicine ,Mitiglinide ,Internal medicine ,Glyburide ,Drug Discovery ,medicine ,Animals ,030212 general & internal medicine ,Dipeptidyl-Peptidase IV Inhibitors ,Glucose tolerance test ,medicine.diagnostic_test ,Chemistry ,Drug Synergism ,General Medicine ,Glucose Tolerance Test ,medicine.disease ,Rats ,Endocrinology ,Diabetes Mellitus, Type 2 ,Sitagliptin ,medicine.drug - Abstract
We compared the individual effects of mitiglinide and glibenclamide administered in combination with the dipeptidyl peptidase-IV (DPP-IV) inhibitor sitagliptin on plasma DPP-IV activity and blood glucose levels in rats with streptozotocin-nicotinamide-induced type 2 diabetes (STZ-NA rats). We examined the inhibitory activity of mitiglinide and glibenclamide as well as their combination with sitagliptin on plasma DPP-IV activity in STZ-NA rats. The oral glucose tolerance test (OGTT) was used to compare effects of mitiglinide, glibenclamide, and their combination with sitagliptin on blood glucose levels in STZ-NA rats. Mitiglinide and glibenclamide did not inhibit rat DPP-IV and did not influence the inhibitory effect of sitagliptin on rat plasma DPP-IV activity. In STZ-NA rats, plasma glucose levels were stronger suppressed by a combination of mitiglinide and sitagliptin than by either drug used alone. However, no clear effect of the combination of glibenclamide and sitagliptin was observed. These results indicate that the combination of mitiglinide and sitagliptin has a lower risk of hypoglycemia in the rats with induced type 2 diabetes compared with the combination of glibenclamide and sitagliptin. The combination of mitiglinide and sitagliptin can be a promising combination for the treatment of diabetic patients.
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- 2017
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7. Ameliorating effect of rovatirelin on the ataxia in rolling mouse Nagoya
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Atsushi Yaguchi, Tomoyuki Ijiro, Ayaka Yokoyama, Yoshikazu Abe, and Sumiyoshi Kiguchi
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0301 basic medicine ,Male ,medicine.medical_specialty ,Cerebellum ,Ataxia ,Pyrrolidines ,Striatum ,Nucleus accumbens ,Biology ,Taltirelin ,03 medical and health sciences ,Mice ,0302 clinical medicine ,Internal medicine ,medicine ,Animals ,Pretectal area ,Thyrotropin-Releasing Hormone ,Oxazolidinones ,Spinocerebellar Degenerations ,Pharmacology ,Behavior, Animal ,Brain-Derived Neurotrophic Factor ,Brain ,medicine.disease ,Ventral tegmental area ,Disease Models, Animal ,030104 developmental biology ,medicine.anatomical_structure ,Endocrinology ,Glucose ,Spinocerebellar ataxia ,Female ,medicine.symptom ,030217 neurology & neurosurgery - Abstract
Rovatirelin is a newly synthetized thyrotropin-releasing hormone (TRH) analog. This study aimed to investigate the effect of rovatirelin on motor function using rolling mouse Nagoya (RMN), a mouse model of hereditary ataxia, and compare it with that of taltirelin, which is clinically used to treat spinocerebellar degeneration in Japan. We also examined the effect of rovatirelin on glucose metabolism in various brain regions of RMN using autoradiography (ARG). Rovatirelin (1, 3, 10, and 30 mg/kg) dose-dependently reduced the fall index in RMN, and its effect was more potent than that of taltirelin (3, 10, 30, and 100 mg/kg). No attenuation of the effect was observed by repeated daily administration for 2 weeks. Furthermore, the reduction in the fall index by rovatirelin persisted for 2 weeks after completing treatment. In the ARG study, rovatirelin induced a significantly elevated uptake of glucose in the prefrontal cortex, nucleus accumbens shell, nucleus accumbens core, striatum, anterior cingulate cortex, secondary motor area, pretectal area, ventral tegmental area, black pars compacta, locus coeruleus, nucleus cerebellaris middle nucleus, medial nucleus of the vestibular nerve, fourth/fifth lobule, and third lobule. Furthermore, rovatirelin increased cerebellar mRNA level of brain derived neurotrophic factor. These results suggest that rovatirelin activates the cerebellum and other parts of the central nervous system to improve motor function in spinocerebellar ataxia (SCA) model animals, and its action is more potent than that of taltirelin. Therefore, rovatirelin can be a potential alternative to the traditionally used therapeutics for SCA.
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- 2019
8. Effect of silodosin, a selective α1A-adrenoceptor antagonist, on voiding behavior and bladder blood flow in a rat model of bladder outlet obstruction
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Yoshitaka Tomiyama, Kazuyasu Maruyama, Ayaka Yokoyama, Mamoru Kobayashi, Osamu Yamaguchi, Satoshi Tatemichi, and Yoshiaki Goi
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medicine.medical_specialty ,Indoles ,Time Factors ,medicine.medical_treatment ,Urinary Bladder ,Ischemia ,Urology ,Urination ,In situ hybridization ,urologic and male genital diseases ,Rats, Sprague-Dawley ,Bladder outlet obstruction ,Receptors, Adrenergic, alpha-1 ,Internal medicine ,Nerve Growth Factor ,Laser-Doppler Flowmetry ,Animals ,Medicine ,Ligature ,In Situ Hybridization ,Pharmacology ,business.industry ,Microcirculation ,Antagonist ,Deoxyguanosine ,Blood flow ,Silodosin ,medicine.disease ,Immunohistochemistry ,Urinary Bladder Neck Obstruction ,Disease Models, Animal ,Urodynamics ,Endocrinology ,Nerve growth factor ,8-Hydroxy-2'-Deoxyguanosine ,Regional Blood Flow ,Adrenergic alpha-1 Receptor Antagonists ,Urological Agents ,Female ,business ,Blood Flow Velocity ,Ureteral Obstruction ,medicine.drug - Abstract
This study was performed to investigate the effects of silodosin (selective α1A-adrenoceptor antagonist) on bladder blood flow (BBF) and bladder function in a rat model of bladder outlet obstruction (BOO) and to determine the expression of α1-adrenoceptor subtype mRNA in human and rat bladder microvessels. BOO was produced by partial ligature of the proximal urethra, which was maintained for 2 weeks. The BOO rats received either silodosin at a rate of 0.3mg/kg/day or vehicle subcutaneously via an osmotic pump for 2 weeks after BOO surgery. A metabolic cage study was performed in conscious animals. BBF was measured using a Laser Speckle Blood Flow Imager. Urinary levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and nerve growth factor (NGF) were measured. Immunohistological examinations of nerve distribution and NGF expression in the rat bladder were conducted. The expression of each α1-adrenoceptor subtype mRNA in human and rat bladder microvessels was determined by in situ hybridization. Silodosin ameliorated the increase in voiding frequency and decrease in mean voided volume in BOO rats in the metabolic cage study. Silodosin also abrogated the decrease in BBF in BOO rats. The levels of 8-OHdG and NGF in BOO rats were significantly decreased by administration of silodosin. Silodosin prevented the decrease in nerve distribution and increase in NGF expression. Human and rat bladder microvessels showed expression of all α1-adrenoceptor subtype mRNAs. The results presented here suggest that silodosin improves voiding behavior in rat models with BOO by inducing recovery of BBF.
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- 2015
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9. Effects of combination of mitiglinide with various oral antidiabetic drugs in streptozotocin-nicotinamide-induced type 2 diabetic rats and Zucker fatty rats
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Hiroo Takeda, Sumiyoshi Kiguchi, Kenji Akahane, Toshihiro Inoue, Kazuma Ojima, Ayaka Yokoyama, Yohsuke Imai, and Satoshi Tatemichi
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0301 basic medicine ,Blood Glucose ,Male ,medicine.medical_specialty ,Physiology ,medicine.drug_class ,medicine.medical_treatment ,030209 endocrinology & metabolism ,Type 2 diabetes ,Pharmacology ,Isoindoles ,Diabetes Mellitus, Experimental ,Rats, Sprague-Dawley ,03 medical and health sciences ,0302 clinical medicine ,Mitiglinide ,Physiology (medical) ,Internal medicine ,Insulin Secretion ,Medicine ,Animals ,Hypoglycemic Agents ,Insulin ,Obesity ,business.industry ,Biguanide ,Glucose Tolerance Test ,medicine.disease ,Rats, Zucker ,030104 developmental biology ,Postprandial ,Endocrinology ,Diabetes Mellitus, Type 2 ,Secretagogue ,Drug Therapy, Combination ,SGLT2 Inhibitor ,business ,Pioglitazone ,medicine.drug - Abstract
We examined the effects of combining the rapid insulin secretagogue, mitiglinide, with various oral hypoglycemic drugs including biguanides, pioglitazone, α-glucosidase inhibitors, and sodium-glucose co-transporter 2 inhibitors in a rat model of type 2 diabetes. The oral glucose tolerance test (OGTT) using glucose, sucrose, or a liquid meal was used to compare the effects of mitiglinide with those of the four oral hypoglycemic drugs and examine their combined effects on blood glucose levels and insulin secretion in the rat model. The combination of mitiglinide with other oral hypoglycemic drugs suppressed the plasma glucose levels more than either agent did alone. Furthermore, the combination of these agents decreased insulin secretion more than mitiglinide did alone. These results indicate that mitiglinide is suitable for use in combination with other hypoglycemic drugs because it inhibits postprandial hyperglycemia by rapidly stimulating insulin secretion. This article is protected by copyright. All rights reserved.
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- 2017
10. Efficacy of Mitiglinide Combined with Dapagliflozin in Streptozotocin-nicotinamide-induced Type 2 Diabetic Rats and in Zucker Fatty Rats
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Mamoru Kobayashi, Toshihiro Inoue, Sumiyoshi Kiguchi, A. Yaguchi, Ayaka Yokoyama, Kenji Akahane, K. Maruyama, Kazuma Ojima, and Y. Mori
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Blood Glucose ,Niacinamide ,medicine.medical_specialty ,medicine.medical_treatment ,Urinary system ,Isoindoles ,Pharmacology ,Streptozocin ,Diabetes Mellitus, Experimental ,Excretion ,chemistry.chemical_compound ,Mitiglinide ,Glucosides ,Diabetes mellitus ,Internal medicine ,Drug Discovery ,medicine ,Animals ,Hypoglycemic Agents ,Insulin ,Benzhydryl Compounds ,Dapagliflozin ,business.industry ,General Medicine ,Glucose Tolerance Test ,medicine.disease ,Rats ,Rats, Zucker ,Endocrinology ,Diabetes Mellitus, Type 2 ,chemistry ,Drug Therapy, Combination ,Secretagogue ,SGLT2 Inhibitor ,business ,medicine.drug - Abstract
The efficacy of the combination of the rapid-acting insulin secretagogue mitiglinide and the sodium-glucose cotransporter 2 (SGLT2) inhibitor dapagliflozin was explored in streptozotocin-nicotinamide-induced type 2 diabetic (STZ-NA) rats and in Zucker fatty (ZF) rats. The STZ-NA rats were prepared at 8 weeks of age. At 9 weeks of age, the combination study was conducted by oral glucose tolerance test (OGTT). At 13 weeks of age, ZF rats were dosed orally with dapagliflozin once daily up to the 22(nd) day. At days 15 and 22, the combination study was conducted by OGTT. In 2 different animal models, plasma glucose levels were strongly suppressed by the combination of mitiglinide and dapagliflozin as compared with either drug alone. The urinary glucose excretion was drastically elevated in the dapagliflozin group, but the combination with mitiglinide suppressed it about 50%. In STZ-NA rats, the plasma insulin secretion by the combination of both drugs was about at the same level as in the mitiglinide group. In ZF rats, the plasma insulin secretion by the combination of both drugs was less than mitiglinide group. Thus, in 2 different animal models, the combination of mitiglinide and dapagliflozin showed stronger antihyperglycemic action accompanied by less insulin secretion than mitiglinide alone, and reduced the urinary glucose excretion as compared with dapagliflozin used alone. These results indicate that the combination of mitiglinide and dapagliflozin can be a promising combination for the treatment of diabetic patients.
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- 2014
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11. Mapping of conserved and species-specific antibody epitopes on the Ebola virus nucleoprotein
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Mari Ishijima, Aaron S. Mweene, Hiroko Miyamoto, Katendi Changula, Reiko Yoshida, Andrea Marzi, Masahiro Kajihara, Ayaka Yokoyama, Heinz Feldmann, Ayato Takada, and Osamu Noyori
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Monoclonal antibody ,Zaire ebolavirus ,Cancer Research ,viruses ,Filoviridae ,Cross Reactions ,Biology ,Antibodies, Viral ,medicine.disease_cause ,Article ,Epitope ,Epitopes ,Mice ,Ebola virus ,Virology ,medicine ,Animals ,Conserved Sequence ,Nucleoprotein ,Ebolavirus ,Antiserum ,Mice, Inbred BALB C ,Viral Core Proteins ,Antibodies, Monoclonal ,Nucleocapsid Proteins ,biology.organism_classification ,Marburgvirus ,Synthetic peptide ,Nucleoproteins ,Infectious Diseases ,Antibody epitope ,Rabbits ,Epitope Mapping - Abstract
Filoviruses (viruses in the genus Ebolavirus and Marburgvirus in the family Filoviridae) cause severe haemorrhagic fever in humans and nonhuman primates. Rapid, highly sensitive, and reliable filovirus-specific assays are required for diagnostics and outbreak control. Characterisation of antigenic sites in viral proteins can aid in the development of viral antigen detection assays such immunochromatography-based rapid diagnosis. We generated a panel of mouse monoclonal antibodies (mAbs) to the nucleoprotein (NP) of Ebola virus belonging to the species Zaire ebolavirus. The mAbs were divided into seven groups based on the profiles of their specificity and cross-reactivity to other species in the Ebolavirus genus. Using synthetic peptides corresponding to the Ebola virus NP sequence, the mAb binding sites were mapped to seven antigenic regions in the C-terminal half of the NP, including two highly conserved regions among all five Ebolavirus species currently known. Furthermore, we successfully produced species-specific rabbit antisera to synthetic peptides predicted to represent unique filovirus B-cell epitopes. Our data provide useful information for the development of Ebola virus antigen detection assays. (C) 2013 Elsevier B.V. All rights reserved.
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- 2013
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12. Characterization of H5N1 highly pathogenic avian influenza virus strains isolated from migratory waterfowl in Mongolia on the way back from the southern Asia to their northern territory
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Hiroshi Kida, Hiroki Takakuwa, Kosuke Soda, Ruuragchaa Sodnomdarjaa, Ayaka Yokoyama, Ayato Takada, Norikazu Isoda, Masatoshi Okamatsu, Eri Nakayama, Yoshihiro Sakoda, Masahiro Kajihara, Noriko Kishida, Naoki Yamamoto, Keita Matsuno, Yoshimi Tsuda, Damdinjav Batchluun, Sengee Sugar, and Tseren-Ochir Erdene-Ochir
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Asia ,Swine ,animal diseases ,Molecular Sequence Data ,Sus scrofa ,Prevalence ,Zoology ,Hemagglutinin Glycoproteins, Influenza Virus ,Avian influenza ,medicine.disease_cause ,Poultry ,Species Specificity ,Migratory waterfowl ,Anseriformes ,Virology ,Waterfowl ,medicine ,Animals ,Amino Acid Sequence ,Northern territory ,Clade ,Phylogeny ,Surveillance ,Influenza A Virus, H5N1 Subtype ,Virulence ,biology ,Ecology ,virus diseases ,Aquatic animal ,Mongolia ,H5N1 ,biology.organism_classification ,Influenza A virus subtype H5N1 ,Ducks ,Whooper swan ,Influenza in Birds ,Animal Migration ,Chickens - Abstract
H5N1 highly pathogenic avian influenza (HPAI) viruses were isolated from dead wild waterfowl at Khunt, Erkhel, Doityn Tsagaan, Doroo, and Ganga Lakes in Mongolia in July 2005, May 2006, May 2009, July 2009, and May 2010, respectively. The isolates in 2005 and 2006 were classified into genetic clade 2.2, and those in 2009 and 2010 into clade 2.3.2. A/whooper swan/Mongolia/6/2009 (H5N1) experimentally infected ducks and replicated systemically with higher mortality than that of the isolates in 2005 and 2006. Intensive surveillance of avian influenza in migratory waterfowl flying from their nesting lakes in Siberia to Mongolia in every autumn indicate that HPAI viruses have not perpetuated at their nesting lakes until 2009. The present results demonstrate that wild waterfowl were sporadically infected with H5N1 HPAI viruses prevailing in domestic poultry in the southern Asia and died in Mongolia on the way back to their northern territory in spring.
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- 2010
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13. Three-dimensional Ultrastructure of Synoviocytes in the Knee Joint of Rabbits and Morphological Changes in Osteoarthritis Model
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Junko Nio, Masahiro Okumura, Toshihiko Iwanaga, and Ayaka Yokoyama
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Male ,Pathology ,medicine.medical_specialty ,Histology ,Materials science ,Knee Joint ,Osteoarthritis ,Imaging, Three-Dimensional ,Interstitial matrix ,Joint capsule ,medicine ,Animals ,Macrophages ,Synovial Membrane ,medicine.disease ,Epithelium ,Microscopy, Electron ,medicine.anatomical_structure ,Microscopy, Electron, Scanning ,Ultrastructure ,Female ,Patella ,Rabbits ,Synovial membrane - Abstract
The synovial intima is composed of two types of synoviocytes: absorptive macrophages and secretory, fibroblast-like F cells. Many studies have tried to observe synoviocytes by scanning electron microscopy (SEM) but failed to reveal the entire shape of synoviocytes because they are deeply embedded in the interstitial matrix. The present study, primarily employing SEM observation of NaOH macerated samples, reveals the distribution and three-dimensional ultrastructure of the synoviocytes in the normal knee joint of rabbits, and the morphological changes of synoviocytes in an osteoarthritis model of this animal. F cells were broadly distributed throughout the synovial intima, while macrophages showed a restricted distribution on fatty tissues around the patella. F cells were classified into a flat type, which covered the surface of synovial membrane like an epithelium, and a dendritic type, which extended long processes to form a characteristic meshwork on the surface. The flat type predominated in regions adhering to the femur, while the dendritic type predominated in ambilateral parts of both the patella and tendon of the musculus quadriceps femoris, and on the peripatellar fatty tissue. Intermediate forms of flat and dendritic types appeared in middle regions between the patella and periphery of the joint capsule. In the synovial membrane of the osteoarthritis model, both types of synoviocytes increased in number and changed their morphology, indicating their elevated activities in absorption and secretion. It is suggested that the ultrastructural changes in synoviocytes reflect pathological conditions of the synovial membrane, and synoviocytes play important roles in the pathogenesis of osteoarthritis.
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- 2002
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14. Enzyme-linked immunosorbent assay for detection of filovirus species-specific antibodies
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Noriko Kishida, Hiroko Miyamoto, Eri Nakayama, Keita Matsuno, Kimihito Ito, Heinz Feldmann, Ayaka Yokoyama, Ayato Takada, Andrea Marzi, Masayuki Saijo, and Manabu Igarashi
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Microbiology (medical) ,Primates ,Clinical Biochemistry ,Immunology ,Filoviridae ,Enzyme-Linked Immunosorbent Assay ,Cross Reactions ,medicine.disease_cause ,Antibodies, Viral ,Sensitivity and Specificity ,Immunoglobulin G ,Serology ,Mice ,Antigen ,Virology ,medicine ,Filoviridae Infections ,Immunology and Allergy ,Animals ,Humans ,Clinical Laboratory Immunology ,Antigens, Viral ,Antiserum ,Mice, Inbred BALB C ,Ebola virus ,biology ,Haplorhini ,biology.organism_classification ,Marburgvirus ,Ebolavirus ,Recombinant Proteins ,Immunoglobulin M ,biology.protein ,Female ,Antibody - Abstract
Several enzyme-linked immunosorbent assays (ELISAs) for the detection of filovirus-specific antibodies have been developed. However, diagnostic methods to distinguish antibodies specific to the respective species of filoviruses, which provide the basis for serological classification, are not readily available. We established an ELISA using His-tagged secreted forms of the transmembrane glycoproteins (GPs) of five different Ebola virus (EBOV) species and one Marburg virus (MARV) strain as antigens for the detection of filovirus species-specific antibodies. The GP-based ELISA was evaluated by testing antisera collected from mice immunized with virus-like particles as well as from humans and nonhuman primates infected with EBOV or MARV. In our ELISA, little cross-reactivity of IgG antibodies was observed in most of the mouse antisera. Although sera and plasma from some patients and monkeys showed notable cross-reactivity with the GPs from multiple filovirus species, the highest reactions of IgG were uniformly detected against the GP antigen homologous to the virus species that infected individuals. We further confirmed that MARV-specific IgM antibodies were specifically detected in specimens collected from patients during the acute phase of infection. These results demonstrate the usefulness of our ELISA for diagnostics as well as ecological and serosurvey studies.
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- 2010
15. Comparison of Antiviral Activity between IgA and IgG Specific to Influenza Virus Hemagglutinin: Increased Potential of IgA for Heterosubtypic Immunity
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Naganori Nao, Hiroko Miyamoto, Ayato Takada, Ayaka Yokoyama, Junki Maruyama, Rashid Manzoor, Mieko Muramatsu, Reiko Yoshida, and Masahiro Kajihara
- Subjects
Viral Diseases ,B Cells ,lcsh:Medicine ,Hemagglutinin Glycoproteins, Influenza Virus ,Adaptive Immunity ,medicine.disease_cause ,Antibodies, Viral ,Epitope ,Madin Darby Canine Kidney Cells ,Mice ,Influenza A virus ,lcsh:Science ,Multidisciplinary ,biology ,Infectious Diseases ,Medicine ,Electrophoresis, Polyacrylamide Gel ,Antibody ,Research Article ,Protein Binding ,medicine.drug_class ,Immune Cells ,Immunology ,Hemagglutinin (influenza) ,Immunoglobulins ,Monoclonal antibody ,Microbiology ,Antiviral Agents ,Virus ,Dogs ,Orthomyxoviridae Infections ,Species Specificity ,Neutralization Tests ,Virology ,Influenza, Human ,medicine ,Animals ,Humans ,Avidity ,Biology ,Heterosubtypic immunity ,lcsh:R ,Immunity ,Virion ,Hemagglutination Inhibition Tests ,Influenza ,Immunoglobulin A ,Immunoglobulin G ,Humoral Immunity ,biology.protein ,lcsh:Q ,Viral Transmission and Infection - Abstract
Both IgA and IgG antibodies are known to play important roles in protection against influenza virus infection. While IgG is the major isotype induced systemically, IgA is predominant in mucosal tissues, including the upper respiratory tract. Although IgA antibodies are believed to have unique advantages in mucosal immunity, information on direct comparisons of the in vitro antiviral activities of IgA and IgG antibodies recognizing the same epitope is limited. In this study, we demonstrate differences in antiviral activities between these isotypes using monoclonal IgA and IgG antibodies obtained from hybridomas of the same origin. Polymeric IgA-producing hybridoma cells were successfully subcloned from those originally producing monoclonal antibody S139/1, a hemaggulutinin (HA)-specific IgG that was generated against an influenza A virus strain of the H3 subtype but had cross-neutralizing activities against the H1, H2, H13, and H16 subtypes. These monoclonal S139/1 IgA and IgG antibodies were assumed to recognize the same epitope and thus used to compare their antiviral activities. We found that both S139/1 IgA and IgG antibodies strongly bound to the homologous H3 virus in an enzyme-linked immunosorbent assay, and there were no significant differences in their hemagglutination-inhibiting and neutralizing activities against the H3 virus. In contrast, S139/1 IgA showed remarkably higher cross-binding to and antiviral activities against H1, H2, and H13 viruses than S139/1 IgG. It was also noted that S139/1 IgA, but not IgG, drastically suppressed the extracellular release of the viruses from infected cells. Electron microscopy revealed that S139/1 IgA deposited newly produced viral particles on the cell surface, most likely by tethering the particles. These results suggest that anti-HA IgA has greater potential to prevent influenza A virus infection than IgG antibodies, likely due to increased avidity conferred by its multivalency, and that this advantage may be particularly important for heterosubtypic immunity.
- Published
- 2014
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