27 results on '"Masao Ito"'
Search Results
2. DESH-G model and Preliminary Architecture for Multiple ADAS system
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Masao Ito
- Subjects
Motor vehicles. Aeronautics. Astronautics ,TL1-4050 - Abstract
Various Advanced Driver Assistance Systems (ADAS) become prevailing recently. In this paper, we argue the safety analysis of combined ADAS systems. The definition of ADAS is vague, so we obey the definition of Code of Practice for the Design and Evaluation of ADAS (CoP) (1). In this definition, the ADAS have to be active, that is, it “provide(s) active support for lateral and/or longitudinal control”. There is a technical report that provides the consolidation way of various warnings emitted by the several ADAS systems (ISO/TR 12204 (2)). However, the problem is not limited to the warning signals. We have to consider the controller of ADAS because it is actively controlled from its definition. We need the more integrated way, and we provide a way to handle this situation by using the idea: DESH-G model.
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- 2019
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3. Circuit Techniques to Improve Low-Light Characteristics and High-Accuracy Evaluation System for CMOS Image Sensor
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Norihito Kato, Fukashi Morishita, Satoshi Okubo, and Masao Ito
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CMOS image sensor ,column-parallel ADC ,multi-functional fine pattern generator ,on-chip test ,Chemical technology ,TP1-1185 - Abstract
The surveillance cameras we focus on target the volume zone, and area reduction is a top priority. However, by simplifying the ADC comparator, we face a new RUSH current issue, for which we propose a circuit solution. This paper proposes two novel techniques of column-ADC for surveillance cameras to improve low-light characteristics. RUSH current compensation reduces transient current consumption fluctuations during AD conversion and utilizing timing shift ADCs decreases the number of simultaneously operating ADCs. These proposed techniques improve low-light characteristics because they reduce the operating noise of the circuit. In order to support small signal measurement, this paper also proposes a high-accuracy evaluation system that can measure both small optical/electrical signals in low-light circumstances. To demonstrate these proposals, test chips were fabricated using a 55 nm CIS process and their optical/electrical characteristics were measured. As a result, low-light linearity as optical characteristics were reduced by 63% and column interference (RUSH current) as an electrical characteristic was also reduced by 50%. As for the high-accuracy evaluation system, we confirmed that the inter-sample variation of column interference was 0.05 LSB. This ADC achieved a figure-of-merit (FoM) of 0.32 e-·pJ/step, demonstrating its usefulness for other ADC architectures while using a single-slope-based simple configuration.
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- 2022
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4. Cerebellar Control of Defense Reactions under Orexin-mediated Neuromodulation as a Model of Cerebellohypothalamic Interaction
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Masao Ito and Naoko Nisimaru
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arterial redistribution ,defense ,flocculus ,neuromodulation ,orexins ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
Recent evidence has indicated that, when an animal is exposed to harmful stimuli, hypothalamic orexinergic neurons are activated via the amygdala and in turn tune the neuronal circuits in the spinal cord, brainstem, and an area of the cerebellum (folium-p of the flocculus) by neuromodulation. The animal would then initiate “defense reactions” composed of complex movements and associated cardiovascular responses. To investigate neuronal mechanisms of the defense reactions, Nisimaru et al. (2013) analyzed cardiovascular responses induced by an electric foot shock stimulus to a rabbit and found two major effects. One is redistribution of arterial blood flow from visceral organs to active muscles, and the other is a modest increase in blood pressure. Kainate-induced lesions of folium-p impaired these two effects. Moreover, folium-p Purkinje cells were shown to project to the parabrachial nucleus, one of the major cardiovascular centers in the brainstem. These data indicate that folium-p Purkinje cells regulate cardiovascular defense reactions via parabrachial nucleus under orexin-mediated neuromodulation. In this article, we review these data from the viewpoint that the defense reactions are expressions of “anger and anxiety”, which respectively lead to “fight and flight” behaviors. The present orexin case may provide a model of cerebellohypothalamic interactions via neuropeptides or amines of hypothalamic origin, which may underlie various types of emotion and behavior.
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- 2014
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5. Via Autonomic Functions and Peptidergic Neuromodulation: Commentary on the AIMS Neuroscience Special Issue on 'What is the Role of the Cerebellum in Emotional Processing and Behavior?'
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Masao Ito
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Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Published
- 2014
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6. Cryptic bumblebee species: consequences for conservation and the trade in greenhouse pollinators.
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Paul H Williams, Jiandong An, Mark J F Brown, James C Carolan, Dave Goulson, Jiaxing Huang, and Masao Ito
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Medicine ,Science - Abstract
Commercial greenhouse growers in both Japan and China are increasingly using reared orange-tailed bumblebees known previously as Bombus hypocrita Pérez as pollinators. Phylogenetic analysis of the DNA (COI) barcodes with Bayesian methods shows that this "species" is a long-standing confusion of two cryptic species. We find that the orange-tailed bumblebees in North China are actually part of the widespread Russian (otherwise white-tailed) B. patagiatus Nylander (as B. patagiatus ganjsuensis Skorikov, n. comb.), whereas the orange-tailed bees in Japan are true B. hypocrita. This situation has been further complicated because two other cryptic species from North China that were previously confused with the Russian B. patagiatus are now recognised as separate: B. lantschouensis Vogt n. stat. and B. minshanensis Bischoff n. stat.. As demand for pollination services by greenhouse growers inevitably increases, these bees are more likely to be transported between countries. In order to conserve genetic resources of pollinator species for their option value for future food security, we advocate preventing trade and movement of B. patagiatus from China into Japan and of B. hypocrita from Japan into China.
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- 2012
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7. Dramatic response to nivolumab after local radiotherapy in pulmonary pleomorphic carcinoma with rapid progressive post‐surgical recurrence
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Sawako Okamoto, Daizo Yaguchi, Hayata Kimura, Motoshi Ichikawa, Kazuko Watanabe, and Masao Ito
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0301 basic medicine ,Pulmonary and Respiratory Medicine ,Oncology ,medicine.medical_specialty ,pulmonary pleomorphic carcinoma ,Immune checkpoint inhibitors ,medicine.medical_treatment ,antitumor immunity ,immune checkpoint inhibitor ,Case Report ,Abscopal effect ,Case Reports ,Pleomorphic carcinoma ,03 medical and health sciences ,0302 clinical medicine ,Cancer immunotherapy ,Internal medicine ,medicine ,Lung cancer ,Pathological ,nivolumab ,business.industry ,Bone metastasis ,General Medicine ,medicine.disease ,030104 developmental biology ,030220 oncology & carcinogenesis ,Nivolumab ,business - Abstract
Pulmonary pleomorphic carcinoma (PPC) is resistant to anticancer drug treatment, outcomes are poor, and no standard therapy has been established. High PD-L1 expression has been found in PPCs, suggesting the possible efficacy of an immune checkpoint inhibitor (ICI) in cancer immunotherapy; however, this approach requires further investigation through case accumulation. Herein, we report a case of rapid recurrence and progression of PPC early after surgery in a 70-year-old male ex-smoker. Surgery was performed for lung cancer of the right lower lobe, and a pathological examination indicated primary PPC with high PD-L1 expression (tumor proportion score: 90%). Because systemic metastasis recurred only six weeks after surgery, nivolumab was administered as second-line treatment. Marked tumor regression was observed on imaging after three cycles, revealing a near complete response. Palliative radiotherapy was applied to the bone metastasis region for pain relief before nivolumab was administered. This case suggests that an ICI can have an effect on PPC and that the efficacy of ICIs may be enhanced by radiotherapy-induced abscopal effects.
- Published
- 2019
8. Dual involvement of G-substrate in motor learning revealed by gene deletion
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Toshiro Sakamoto, Toshio Ikeda, Kazuhiko Yamaguchi, Masao Ito, Paul Greengard, Kazuyuki Yamada, Shigenori Kawahara, Shigeyoshi Itohara, Fumihiro Shutoh, Shogo Endo, Dai Yanagihara, Angus C. Nairn, Takehito Okamoto, Michiyuki Suzuki, Tung Le Dinh, Soichi Nagao, Yamato Sato, Yutaka Kirino, and Nicholas A. Hartell
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Cerebellum ,Time Factors ,genetic structures ,Adaptation, Biological ,Stimulation ,Parallel fiber ,Nerve Tissue Proteins ,Biology ,Mice ,Ocular Motility Disorders ,medicine ,Animals ,Learning ,Motor Neuron Disease ,Mice, Knockout ,Multidisciplinary ,Depression ,Optokinetic reflex ,Biological Sciences ,Mice, Inbred C57BL ,Electrophysiology ,medicine.anatomical_structure ,Eyeblink conditioning ,Knockout mouse ,Motor learning ,Neuroscience ,Gene Deletion - Abstract
In this study, we generated mice lacking the gene for G-substrate, a specific substrate for cGMP-dependent protein kinase uniquely located in cerebellar Purkinje cells, and explored their specific functional deficits. G-substrate–deficient Purkinje cells in slices obtained at postnatal weeks (PWs) 10–15 maintained electrophysiological properties essentially similar to those from WT littermates. Conjunction of parallel fiber stimulation and depolarizing pulses induced long-term depression (LTD) normally. At younger ages, however, LTD attenuated temporarily at PW6 and recovered thereafter. In parallel with LTD, short-term (1 h) adaptation of optokinetic eye movement response (OKR) temporarily diminished at PW6. Young adult G-substrate knockout mice tested at PW12 exhibited no significant differences from their WT littermates in terms of brain structure, general behavior, locomotor behavior on a rotor rod or treadmill, eyeblink conditioning, dynamic characteristics of OKR, or short-term OKR adaptation. One unique change detected was a modest but significant attenuation in the long-term (5 days) adaptation of OKR. The present results support the concept that LTD is causal to short-term adaptation and reveal the dual functional involvement of G-substrate in neuronal mechanisms of the cerebellum for both short-term and long-term adaptation.
- Published
- 2009
9. LES/flamelet/ANN of oxy-fuel combustion for a supercritical CO2 power cycle
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Hiroki Kasuya, Yasunori Iwai, Masao Itoh, Yuichi Morisawa, Takayuki Nishiie, Reo Kai, and Ryoichi Kurose
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Oxy-fuel supercritical CO2 cycle ,Large eddy simulation ,Flamelet/progress-variable model ,Artificial neural network ,Fuel ,TP315-360 ,Energy industries. Energy policy. Fuel trade ,HD9502-9502.5 - Abstract
Large eddy simulation (LES) employing a flamelet model coupled with an artificial neural network (ANN), namely the LES/flamelet/ANN is developed for supercritical oxy-fuel combustion and its validity is investigated in detail. An ANN is introduced to reduce the size of the flamelet library for non-adiabatic three gas-stream conditions of a real supercritical carbon dioxide (CO2) combustor. The fuel and oxidizer are methane (CH4) and a mixture of oxygen (O2) and CO2, respectively. To consider the real gas effect, the Soave-Redlich-Kwong (SRK) equation of state is solved to generate the flamelet library. The LES/flamelet/ANN is applied to two combustion fields in the combustor, namely the upstream and full fields of the combustor with low and high mesh sizes, respectively. The LES/flamelet/ANN for the upstream field is conducted to examine its applicability to the non-adiabatic three gas streams condition by varying the resolution of the flamelet library and by comparing it with the results obtained by the conventional LES/flamelet. The LES/flamelet/ANN for the full field is also conducted to validate the approach by comparing its results with those obtained from the experiment. The results show that the LES/flamelet/ANN of the upstream field properly reproduces the supercritical combustion behavior generated by the conventional LES/flamelet while maintaining the same level of computational cost. Furthermore, the LES/flamelet/ANN for the full field reasonably predicts the supercritical combustion behavior in the experiment, and the predicted combustor outlet temperature agrees well with the experimental results.
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- 2022
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10. Tandem internal models execute motor learning in the cerebellum.
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Takeru Honda, Yuji Hashimoto, Kinya Ishikawa, Takanori Yokota, Soichi Nagao, Hidehiro Mizusawa, and Masao Ito
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MOTOR learning ,CEREBELLUM ,LEARNING ,COGNITION ,NEUROLOGICAL disorders - Abstract
In performing skillful movement, humans use predictions from internal models formed by repetition learning. However, the computational organization of internal models in the brain remains unknown. Here, we demonstrate that a computational architecture employing a tandem configuration of forward and inverse internal models enables efficient motor learning in the cerebellum. The model predicted learning adaptations observed in handreaching experiments in humans wearing a prism lens and explained the kinetic components of these behavioral adaptations. The tandem system also predicted a form of subliminal motor learning that was experimentally validated after training intentional misses of hand targets. Patients with cerebellar degeneration disease showed behavioral impairments consistent with tandemly arranged internal models. These findings validate computational tandemization of internal models in motor control and its potential uses in more complex forms of learning and cognition. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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11. Tuberculous pleurisy mimicking Mycoplasma pneumoniae infection in a previously healthy young adult: A case report.
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Daizo Yaguchi, Motoshi Ichikawa, Masato Shizu, Noriko Inoue, Daisuke Kobayashi, Naoyuki Imai, Masao Ito, Yaguchi, Daizo, Ichikawa, Motoshi, Shizu, Masato, Inoue, Noriko, Kobayashi, Daisuke, Imai, Naoyuki, and Ito, Masao
- Published
- 2018
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12. Cerebellum, The : Brain for an Implicit Self
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Masao Ito and Masao Ito
- Subjects
- Cerebellum--Physiology, Neuroplasticity, Motor Neurons--physiology, Neuronal Plasticity, Synaptic Transmission--physiology
- Abstract
Leading neuroscientist Dr. Masao Ito advances a detailed and fascinating view of what the cerebellum contributes to brain function. The cerebellum has been seen as primarily involved in coordination of body movement control, facilitating the learning of motor skills such as those involved in walking, riding a bicycle, or playing a piano. The cerebellum is now viewed as an assembly of numerous neuronal machine modules, each of which provides an implicit learning capability to various types of motor control. The cerebellum enables us to unconsciously learn motor skills through practice by forming internal models simulating control system properties of the body parts. Based on these remarkable advances in our understanding of motor control mechanisms of the cerebellum, Ito presents a still larger view of the cerebellum as serving a higher level of brain functions beyond movements, including the implicit part of the thought and cognitive processes that manipulate knowledge. Ito extends his investigation of the cerebellum to discuss neural processes that may be involved implicitly in such complex mental actions as having an intuition, imagination, hallucination, or delusion.
- Published
- 2011
13. Cryptic Bumblebee Species: Consequences for Conservation and the Trade in Greenhouse Pollinators
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Dave Goulson, Jiaxing Huang, Masao Ito, Paul H. Williams, Jiandong An, Mark J. F. Brown, and James C. Carolan
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Species complex ,China ,Conservation of Natural Resources ,Pollination ,Population ,Molecular Sequence Data ,lcsh:Medicine ,Crops ,Plant Science ,DNA barcoding ,Japan ,Species Specificity ,Pollinator ,Animals ,DNA Barcoding, Taxonomic ,Evolutionary Systematics ,Hypocrita ,education ,lcsh:Science ,Biology ,Bumblebee ,Phylogeny ,Taxonomy ,education.field_of_study ,Evolutionary Biology ,Multidisciplinary ,biology ,Base Sequence ,Models, Genetic ,Ecology ,lcsh:R ,Botany ,Bayes Theorem ,Agriculture ,Sequence Analysis, DNA ,Faculty of Science\Biological Science ,Bees ,Plants ,biology.organism_classification ,Palynology ,Genetics, Population ,lcsh:Q ,Zoology ,Research Article ,Research Groups and Centres\Ecology Evolution and Behaviour - Abstract
Commercial greenhouse growers in both Japan and China are increasingly using reared orange-tailed bumblebees known previously as Bombus hypocrita Pérez as pollinators. Phylogenetic analysis of the DNA (COI) barcodes with Bayesian methods shows that this "species" is a long-standing confusion of two cryptic species. We find that the orange-tailed bumblebees in North China are actually part of the widespread Russian (otherwise white-tailed) B. patagiatus Nylander (as B. patagiatus ganjsuensis Skorikov, n. comb.), whereas the orange-tailed bees in Japan are true B. hypocrita. This situation has been further complicated because two other cryptic species from North China that were previously confused with the Russian B. patagiatus are now recognised as separate: B. lantschouensis Vogt n. stat. and B. minshanensis Bischoff n. stat. As demand for pollination services by greenhouse growers inevitably increases, these bees are more likely to be transported between countries. In order to conserve genetic resources of pollinator species for their option value for future food security, we advocate preventing trade and movement of B. patagiatus from China into Japan and of B. hypocrita from Japan into China. © 2012 Williams et al.
- Published
- 2012
- Full Text
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14. Unveiling cryptic species of the bumblebee subgenus Bombus s. str. worldwide with COI barcodes (Hymenoptera: Apidae)
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Mark J. F. Brown, A. Murat Aytekin, Jiaxing Huang, Rifat Raina, Paul Schmid-Hempel, Alexander M. Byvaltsev, James C. Carolan, Jiandong An, Lincoln R Best, Peter Šima, Robert Dawson, Alireza Monfared, Masao Ito, Dave Goulson, Paul H. Williams, Zenghua Xie, Cory S. Sheffield, and Björn Cederberg
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Systematics ,Species complex ,Ecology ,Plant Science ,Hymenoptera ,Faculty of Science\Biological Science ,Biology ,biology.organism_classification ,barcoding ,Bombus ,bumblebees ,taxonomy ,Taxon ,Pollinator ,lucorum-complex ,Taxonomy (biology) ,pollinators ,Subgenus ,systematics ,Ecology, Evolution, Behavior and Systematics ,Bumblebee ,Research Groups and Centres\Ecology Evolution and Behaviour - Abstract
Bumblebees of the subgenus Bombus s. str. dominate (or used to dominate) many north temperate pollinator assemblages and include most of the commercial bumblebee pollinator species. Several species are now in serious decline, so conservationists need to know precisely which ones are involved. The problem is that many Bombus s. str. species are cryptic, so that species identification from morphology may be impossible for some individuals and is frequently misleading according to recent molecular studies. This is the first review of the entire subgenus to: (1) avoid fixed a priori assumptions concerning the limits of the problematic species; and (2) sample multiple sites from across the entire geographic ranges of all of the principal named taxa worldwide; and (3) fit an explicit model for how characters change within an evolutionary framework; and (4) apply explicit and consistent criteria within this evolutionary framework for recognising species. We analyse easily-obtained DNA (COI-barcode) data for 559 sequences from 279 localities in 33 countries using general mixed Yule-coalescent (GMYC) models, assuming only the morphologically distinctive species B. affinis Cresson, B. franklini (Frison), B. ignitus Smith and B. tunicatus Smith, and then recognise other comparable COI-barcode groups as putative species. These species correspond to modified concepts of the taxa B. cryptarum (Fabricius), B. hypocrita Pérez, B. jacobsoni Skorikov, B. lantschouensis Vogt n. stat., B. longipennis Friese, B. lucorum (Linnaeus), B. magnus Vogt, B. minshanensis Bischoff n. stat., B. occidentalis Greene, B. patagiatus Nylander, B. sporadicus Nylander, B. terrestris (Linnaeus) and B. terricola Kirby (a total of 17 species). Seven lectotypes are designated. Our results allow us for the first time to diagnose all of the putative species throughout their global ranges and to map the extent of these geographic ranges.
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- 2012
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15. A hybrid nanofiber matrix to control the survival and maturation of brain neurons
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Eugene T. Pashuck, Masao Ito, Shantanu Sur, Mustafa O. Guler, Thomas Launey, Samuel I. Stupp, and Güler, Mustafa O.
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Materials science ,Nanofibers ,Biophysics ,Biocompatible Materials ,Bioengineering ,Nerve tissue engineering ,Collagen Type I ,Article ,Epitope ,Biomaterials ,Extracellular matrix ,Purkinje Cells ,Tissue engineering ,Laminin ,Peptide amphiphile ,medicine ,Animals ,Rats, Wistar ,Neurons ,Tissue Engineering ,Tissue Scaffolds ,biology ,Brain ,Cell Differentiation ,Peptide Fragments ,Extracellular Matrix ,Rats ,medicine.anatomical_structure ,Mechanics of Materials ,Nanofiber ,Cerebellar cortex ,Ceramics and Composites ,biology.protein ,Neuron ,Collagen ,Biomedical engineering - Abstract
Scaffold design plays a crucial role in developing graft-based regenerative strategies, especially when intended to be used in a highly ordered nerve tissue. Here we describe a hybrid matrix approach, which combines the structural properties of collagen (type I) with the epitope-presenting ability of peptide amphiphile (PA) nanofibers. Self-assembly of PA and collagen molecules results in a nanofibrous scaffold with homogeneous fiber diameter of 20-30 nm, where the number of laminin epitopes IKVAV and YIGSR can be varied by changing the PA concentrations over a broad range of 0.125-2 mg/ml. Granule cells (GC) and Purkinje cells (PC), two major neuronal subtypes of cerebellar cortex, demonstrate distinct response to this change of epitope concentration. On IKVAV hybrid constructs, GC density increases three-fold compared with the control collagen substrate at a PA concentration of ≥0.25 mg/ml, while PC density reaches a maximum (five-fold vs. control) at 0.25 mg/ml of PA and rapidly decreases at higher PA concentrations. In addition, adjustment of the epitope number allowed us to achieve fine control over PC dendrite and axon growth. Due to the ability to modulate neuron survival and maturation by easy manipulation of epitope density, our design offers a versatile test bed to study the extracellular matrix (ECM) contribution in neuron development and the design of optimal neuronal scaffold biomaterials. © 2011 Elsevier Ltd.
- Published
- 2012
16. Molecular identification of human G-substrate, a possible downstream component of the cGMP-dependent protein kinase cascade in cerebellar Purkinje cells
- Author
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Paul Greengard, Ryoji Morita, Masao Ito, Masako Suzuki, Kazuhiro Yamakawa, Angus C. Nairn, Shogo Endo, and Mariko Sumi
- Subjects
Transcription, Genetic ,Molecular Sequence Data ,Nerve Tissue Proteins ,Biology ,MAP2K7 ,Purkinje Cells ,Cerebellum ,HSPA2 ,Cyclic GMP-Dependent Protein Kinases ,Animals ,Humans ,Protein phosphorylation ,c-Raf ,Amino Acid Sequence ,RNA, Messenger ,Cloning, Molecular ,Protein kinase A ,Expressed Sequence Tags ,Multidisciplinary ,Base Sequence ,Sequence Homology, Amino Acid ,Brain ,Protein phosphatase 2 ,Autophagy-related protein 13 ,Biological Sciences ,Molecular biology ,Recombinant Proteins ,Biochemistry ,Databases as Topic ,Rabbits ,cGMP-dependent protein kinase ,Sequence Alignment - Abstract
G-substrate, an endogenous substrate for cGMP-dependent protein kinase, exists almost exclusively in cerebellar Purkinje cells, where it is possibly involved in the induction of long-term depression. A G-substrate cDNA was identified by screening expressed sequence tag databases from a human brain library. The deduced amino acid sequence of human G-substrate contained two putative phosphorylation sites (Thr-68 and Thr-119) with amino acid sequences [KPRRKDT(p)PALH] that were identical to those reported for rabbit G-substrate. G-substrate mRNA was expressed almost exclusively in the cerebellum as a single transcript. The human G-substrate gene was mapped to human chromosome 7p15 by radiation hybrid panel analysis. In vitro translation products of the cDNA showed an apparent molecular mass of 24 kDa on SDS/PAGE which was close to that of purified rabbit G-substrate (23 kDa). Bacterially expressed human G-substrate is a heat-stable and acid-soluble protein that cross-reacts with antibodies raised against rabbit G-substrate. Recombinant human G-substrate was phosphorylated efficiently by cGMP-dependent protein kinase exclusively at Thr residues, and it was recognized by antibodies specific for rabbit phospho-G-substrate. The amino acid sequences surrounding the sites of phosphorylation in G-substrate are related to those around Thr-34 and Thr-35 of the dopamine- and cAMP-regulated phosphoprotein DARPP-32 and inhibitor-1, respectively, two potent inhibitors of protein phosphatase 1. However, purified G-substrate phosphorylated by cGMP-dependent protein kinase inhibited protein phosphatase 2A more effectively than protein phosphatase 1, suggesting a distinct role as a protein phosphatase inhibitor.
- Published
- 1999
17. Reassessment of long-term depression in cerebellar Purkinje cells in mice carrying mutated GluA2 C terminus.
- Author
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Kazuhiko Yamaguchi, Shigeyoshi Itohara, and Masao Ito
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LONG-term synaptic depression ,PURKINJE cells ,MOTOR learning ,GENETIC mutation ,PHOSPHORYLATION ,GLUTAMATE receptors - Abstract
Long-term depression (LTD) of synaptic transmission from parallel fibers (PFs) to a Purkinje cell (PC) in the cerebellum has been considered to be a core mechanism of motor learning. Recently, however, discrepancies between LTD and motor learning have been reported in mice with a mutation that targeted the expression of PF-PC LTD by blocking AMPA-subtype glutamate receptor internalization regulated via the phosphorylation of AMPA receptors. In these mice, motor learning behavior was normal, but no PF-PC LTD was observed. We reexamined slices obtained from these GluA2 K882A and GluA2 Δ7 knockin mutants at 3-6 mo of age. The conventional protocols of stimulation did not induce LTD in these mutant mice, as previously reported, but surprisingly, LTD was induced using certain modified protocols. Such modifications involved increases in the number of PF stimulation (from one to two or five), replacement of climbing fiber stimulation with somatic depolarization (50 ms), filling a patch pipette with a Cs
+ -based solution, or extension of the duration of conjunction. We also found that intracellular infusion of a selective PKCα inhibitor (Gö6976) blocked LTD induction in the mutants, as in WT, suggesting that functional compensation occurred downstream of PKCα. The possibility that LTD in the mutants was caused by changes in membrane resistance, access resistance, or presynaptic property was excluded. The present results demonstrate that LTD is inducible by intensified conjunctive stimulations even in K882A and Δ7 mutants, indicating no contradiction against the LTD hypothesis of motor learning. [ABSTRACT FROM AUTHOR]- Published
- 2016
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18. Orexin-neuromodulated cerebellar circuit controls redistribution of arterial blood flows for defense behavior in rabbits.
- Author
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Naoko Nisimaru, Mittal, Chetan, Yoshinori Shirai, Thongchai Sooksawate, Anandaraj, Prabu, Tsutomu Hashikawa, Soichi Nagao, Akiko Arata, Takeshi Sakurai, Miyuki Yamamoto, and Masao Ito
- Subjects
CEREBELLUM ,OREXINS ,NEURAL circuitry ,BLOOD flow ,MAMMAL defenses ,PURKINJE cells ,AXONS ,LABORATORY rabbits - Abstract
We investigated a unique microzone of the cerebellum located in folium-p (fp) of rabbit flocculus. In fp, Purkinje cells were potently excited by stimulation of the hypothalamus or mesencephalic periaqueductal gray, which induced defense reactions. Using multiple neuroscience techniques, we determined that this excitation was mediated via beaded axons of orexinergic hypothalamic neurons passing collaterals through the mesencephalic periaqueductal gray. Axonal tracing studies using DiI and biotinylated dextran amine evidenced the projection of fp Purkinje cells to the ventrolateral corner of the ipsilateral parabrachial nucleus (PBN). Because, in defense reactions, arterial blood flow has been known to redistribute from visceral organs to active muscles, we hypothesized that, via PBN, fp adaptively controls arterial blood flow redistribution under orexin-mediated neuromodulation that could occur in defense behavior. This hypothesis was supported by our finding that climbing fiber signals to fp Purkinje cells were elicited by stimulation of the aortic nerve, a high arterial blood pressure, or a high potassium concentration in muscles, all implying errors in the control of arterial blood flow. We further examined the arterial blood flow redistribution elicited by electric foot shock stimuli in awake, behaving rabbits. We found that systemic administration of an orexin antagonist attenuated the redistribution and that lesioning of fp caused an imbalance in the redistribution between active muscles and visceral organs. Lesioning of fp also diminished foot shock-induced increases in the mean arterial blood pressure. These results collectively support the hypothesis that the fp microcomplex adaptively controls defense reactions under orexin-mediated neuromodulation. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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19. Asymmetrical allocation of mitochondrial DNA to blastomeres during the first two cleavages in mouse embryos.
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Yuichi Kameyama, Hidehisa Ohnishi, Gaku Shimoi, Ryoichi Hashizume, Masao Ito, and Lawrence C. Smith
- Subjects
MITOCHONDRIAL DNA ,BLASTOMERES ,EMBRYOS ,OXYGEN consumption ,ADENOSINE triphosphatase ,CYTOKINESIS ,LABORATORY mice - Abstract
A recent report showed higher oxygen consumption, adenosine triphosphate (ATP) production and mitochondrial localisation in trophectoderm cells than in the inner cell mass of mouse blastocysts. We hypothesised that this phenomenon was due to the asymmetrical distribution of mitochondria in the blastomeres during the earlier stages. Oocytes, 2-cell embryos and 4-cell embryos were analysed to determine the volume, ATP content and mitochondrial DNA (mtDNA) copy number in the whole egg and individual blastomeres. Significant differences were detected in the volumes of cytoplasm and ATP contents between blastomeres from the 2-cell and 4-cell embryos. Moreover, whilst remaining stable in whole embryos, mtDNA copy number differed between blastomeres, indicating that mitochondria in oocytes are unevenly delivered into the daughter blastomeres during the first two cleavages. Although their volume and ATP content were not correlated, there was a significant correlation between volume and mtDNA copy number in 2- and 4-cell blastomeres. These results indicate that the number of mitochondria delivered to blastomeres during early cleavage is not precisely equal, suggesting that the allocation of mitochondria into daughter blastomeres is affected by uneven cytoplasmic distribution during cytokinesis in the oocyte and mother blastomeres. [ABSTRACT FROM AUTHOR]
- Published
- 2010
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20. Loss of heterozygosity of chromosome 12p does not correlate with KRAS mutation in non-small cell lung cancer.
- Author
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Mika Uchiyama, Noriyasu Usami, Masashi Kondo, Shoichi Mori, Masao Ito, Genshi Ito, Hiromu Yoshioka, Munehisa Imaizumi, Yuichi Ueda, Masahide Takahashi, John D. Minna, Kaoru Shimokata, and Yoshitaka Sekido
- Subjects
GENETIC mutation ,LUNG cancer ,CARCINOGENESIS - Abstract
Activating mutations of RAS gene families have been found in a variety of human malignancies, including lung cancer, suggesting their dominant role in tumorigenesis. However, several studies have shown a frequent loss of the wild-type KRAS allele in the tumors of murine models and an inhibition of oncogenic phenotype in tumor cell lines by transfection of wild-type RAS, indicating that wild-type RAS may have oncosuppressive properties. To determine whether loss of wild-type KRAS is involved in the development of human lung cancer, we investigated the mutations of KRAS, NRAS and BRAF in 154 primary non-small cell lung cancers (NSCLCs) as well as 10 NSCLC cell lines that have been shown to have KRAS mutations. We also determined the loss of heterozygosity status of KRAS alleles in these tumors. We detected point mutations of KRAS in 11 (7%) of 154 NSCLCs, with 10 cases at codon 12 and 1 at codon 61, but no mutations of NRAS or BRAF were found. Using the laser capture microdissection technique, we confirmed that 9 of the 11 tumors and 7 of the 10 NSCLC cell lines retained the wild-type KRAS allele. Among the cell lines with heterozygosity of mutant and wild-type KRAS, all of the cell lines tested for expression were shown to express more mutated KRAS than wild-type mRNA, with higher amounts of KRAS protein also being expressed compared to the cell lines with a loss of wild-type KRAS allele. In addition, among 148 specimens available for immunohistochemical analysis, 113 (76%) showed positive staining of KRAS, indicating that the vast majority of NSCLCs continue to express wild-type KRAS. Our findings indicate that the wild-type KRAS allele is occasionally lost in human lung cancer, and that the oncogenic activation of mutant KRAS is more frequently associated with an overexpression of the mutant allele than with a loss of the wild-type allele in human NSCLC development. © 2003 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]
- Published
- 2003
- Full Text
- View/download PDF
21. Induction of Long-Term Depression in Cerebellar Purkinje Cells Requires a Rapidly Turned Over Protein.
- Author
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LADDAWAN KARACHOT, YOSHINORI SHIRAI, VIGOT, RÉJAN, TETSUO YAMAMORI, and MASAO ITO
- Published
- 2001
- Full Text
- View/download PDF
22. Improved synthesis of DQ-113, a new quinolone antibacterial agent, utilizing the Reformatsky reaction
- Author
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Hiroaki Inagaki, Kazuyuki Sugita, Rie N. Miyauchi, Satoru Miyauchi, Toshiyuki Takeda, Masao Itoh, Hisashi Takahashi, and Makoto Takemura
- Subjects
Organic chemistry ,QD241-441 - Published
- 2003
- Full Text
- View/download PDF
23. Role of IUPS in Facing New Frontiers for Physiology.
- Author
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Masao Ito
- Published
- 1995
24. Comparative aspects of horizontal ocular reflexes and their cerebellar adaptive control in vertebrates
- Author
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Masao, Ito and Soichi, Nagao
- Published
- 1991
- Full Text
- View/download PDF
25. Cognition, Computation, and Consciousness
- Author
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Masao Ito, Yasushi Miyashita, Edmund T. Rolls, Masao Ito, Yasushi Miyashita, and Edmund T. Rolls
- Subjects
- Neurosciences, Physical sciences, Psychology, Cognition, Cognitive neuroscience, Philosophy of mind, Consciousness, Psychophysiology, Life sciences, Human information processing
- Abstract
The topic of consciousness is truly multidisciplinary, attracting researchers and theorists from diverse backgrounds. It is now widely accepted that previously disparate areas all have contributions to make to the understanding of the nature of consciousness. Thus, we now have computational scientists, neuroscientists, and philosophers all engaged in the same effort. This book illustrates these three approaches, with chapters provided by some of the most important and provocative figures in the field. The first section is concerned with philosophical approaches to consciousness. One of the fundamental issues here is that of subjective feeling or qualia. The second section focuses on approaches from cognitive neuroscience. Patients with different types of neurological problems, and new imaging techniques, provide rich sources of data for studying how consciousness relates to brain function. The third section includes computational approaches looking at the quantitative relationship between brain processes and conscious experience. Cognition, Computation, and Consciousness represents a uniquely integrated and current account of this most fascinating and intractable subject.
- Published
- 1997
26. Brain Signal Transduction and Memory
- Author
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Masao Ito and Masao Ito
- Subjects
- Neural transmission, Neuroplasticity, Neural transmission--Congresses, Memory--Physiological aspects--Congresses, Neurotransmitter receptors
- Abstract
Brain Signal Transduction and Memory is a compilation of the proceedings of the Fifth Takeda Science Foundation Symposium on Bioscience, held on November 28-30, 1988, in Kyoto, Japan. The symposium provided a forum for the discussion of a wide range of topics on brain signal transduction and its role in memory formation. Topics covered include the role of phosphoinositides in neural signaling; the homeostasis of calcium ions; the involvement of protein kinase C in brain signal transduction and memory formation; long-term potentiation in the hippocampus; synaptic plasticity and memory; and organization of neural tissues by plasticity. This book is comprised of 21 chapters and begins with an analysis of the phosphoinositide signaling system and how it might function within the nervous system, followed by a discussion on the molecular heterogeneity of the protein kinase C family and its implications for the regulation of neuronal cells. The formation and reorganization of synaptic contacts in the developing nervous system, as well as the factors that influence the plasticity of this process, are then explored. Other chapters focus on the biochemical mechanisms involved in the generation and maintenance of enhanced synaptic transmission; quantal release in the hippocampus; molecular mechanisms of long-term depression in the cerebellum; and cellular mechanisms for reorganization of synaptic inputs after early brain damage. This monograph will appeal to biologists, physiologists, bioscientists, and clinicians.
- Published
- 1989
27. Control of mental activities by internal models in the cerebellum.
- Author
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Ito M
- Subjects
- Animals, Feedback, Humans, Nerve Net physiology, Nonlinear Dynamics, Cerebellum anatomy & histology, Cerebellum physiology, Mental Processes physiology, Models, Neurological
- Abstract
The intricate neuronal circuitry of the cerebellum is thought to encode internal models that reproduce the dynamic properties of body parts. These models are essential for controlling the movement of these body parts: they allow the brain to precisely control the movement without the need for sensory feedback. It is thought that the cerebellum might also encode internal models that reproduce the essential properties of mental representations in the cerebral cortex. This hypothesis suggests a possible mechanism by which intuition and implicit thought might function and explains some of the symptoms that are exhibited by psychiatric patients. This article examines the conceptual bases and experimental evidence for this hypothesis.
- Published
- 2008
- Full Text
- View/download PDF
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