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181 results on '"Yamaguchi, Akinori"'

7. Investigation of Clinical Features and Association between Vascular Endothelial Injury Markers and Cytomegalovirus Infection Associated with Thrombotic Microangiopathy in Patients with Anti-Neutrophil Cytoplasmic Antibody (ANCA)-Associated Vasculitis: Case-Based Research

Author

Nimura, Takayuki, primary, Aomura, Daiki, additional, Harada, Makoto, additional, Yamaguchi, Akinori, additional, Yamaka, Kosuke, additional, Nakajima, Takero, additional, Tanaka, Naoki, additional, Ehara, Takashi, additional, Hashimoto, Koji, additional, and Kamijo, Yuji, additional

Published
2024
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9. Prediction of amyloid positron emission tomography positivity using multiple regression analysis of quantitative susceptibility mapping

Author

Ikebe, Yohei, primary, Sato, Ryota, additional, Amemiya, Tomoki, additional, Udo, Niki, additional, Matsushima, Masaaki, additional, Yabe, Ichiro, additional, Yamaguchi, Akinori, additional, Sasaki, Makoto, additional, Harada, Masafumi, additional, Matsukawa, Noriyuki, additional, Kawata, Yasuo, additional, Bito, Yoshitaka, additional, Shirai, Toru, additional, Ochi, Hisaaki, additional, and Kudo, Kohsuke, additional

Published
2023
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10. Efficacy of Quantitative Susceptibility Mapping with Brain Surface Correction and Vein Removal for Detecting Increase Magnetic Susceptibility in Patients with Alzheimer's Disease

Author

Yamaguchi, Akinori, 1000010374232, Kudo, Kohsuke, Sato, Ryota, Kawata, Yasuo, Udo, Niki, Matsushima, Masaaki, Yabe, Ichiro, Sasaki, Makoto, Harada, Masafumi, Matsukawa, Noriyuki, Shirai, Toru, Ochi, Hisaaki, Bito, Yoshitaka, Yamaguchi, Akinori, 1000010374232, Kudo, Kohsuke, Sato, Ryota, Kawata, Yasuo, Udo, Niki, Matsushima, Masaaki, Yabe, Ichiro, Sasaki, Makoto, Harada, Masafumi, Matsukawa, Noriyuki, Shirai, Toru, Ochi, Hisaaki, and Bito, Yoshitaka

Abstract

Purpose: Studies on quantitative susceptibility mapping (QSM) have reported an increase in magnetic susceptibilities in patients with Alzheimer's disease (AD). Despite the pathological importance of the brain surface areas, they are sometimes excluded in QSM analysis. This study aimed to reveal the efficacy of QSMMethods: Thirty-seven AD patients and 37 age- and sex-matched, cognitively normal (CN) subjects were included. A 3D-gradient echo sequence at 3T MRI was used to obtain QSM. QSM images were created with regularization enabled sophisticated harmonic artifact reduction for phase data (RESHARP) and constrained RESHARP with BSC and/or VR. We conducted ROI analysis between AD patients and CN subjects who did or did not undergo BSC and/or VR using a t-test, to compare the susceptibility values after gray matter weighting. Results: The susceptibility values in RESHARP without BSC were significantly larger in AD patients than in CN subjects in one region (precentral gyrus, 8.1 +/- 2.9 vs. 6.5 +/- 2.1 ppb) without VR and one region with VR (precentral gyrus, 7.5 +/- 2.8 vs. 5.9 +/- 2.0 ppb). Three regions in RESHARP with BSC had significantly larger susceptibilities without VR (precentral gyrus, 7.1 +/- 2.0 vs. 5.9 +/- 2.0 ppb; superior medial frontal gyrus, 5.7 +/- 2.6 vs. 4.2 +/- 3.1 ppb; putamen, 47,8 +/- 16.5 vs. 40.0 +/- 15.9 ppb). In contrast, six regions showed significantly larger susceptibilities with VR in AD patients than in CN subjects (precentral gyrus, 6.4 +/- 1.9 vs. 4.9 +/- 2.7 ppb; superior medial frontal gyrus, 5.3 +/- 2.7 vs. 3.7 +/- 3.3 ppb; orbitofrontal cortex, -2.1 +/- 2.7 vs. -3.6 +/- 3.2 ppb; parahippocampal gyrus, 0.1 +/- 3.6 vs. -1.7 +/- 3.7 ppb; putamen, 45.0 +/- 14.9 vs. 37.6 +/- 14.6 ppb; inferior temporal gyrus, -3.4 +/- 1.5 vs. -4.4 +/- 1.5 ppb).Conclusion: RESHARP with BSC and VR showed more regions of increased susceptibility in AD patients than in CN subjects. This study highlights the efficacy of this method in facilitating the dia

Published
2023

11. Outcomes of critically ill patients with liver failure who require mechanical ventilation: A retrospective, single‐center study.

Author

Mita, Atsuyoshi, Shimizu, Sari, Ichiyama, Takashi, Yamamoto, Takateru, Yamaguchi, Akinori, Sonoda, Kosuke, Mori, Kotaro, Yamada, Tomokatsu, Nakamura, Hiroyuki, and Imamura, Hiroshi

Abstract

Background and Aims: Critically ill patients with liver failure have high mortality. Besides the management of organ‐specific complications, liver transplantation constitutes a definitive treatment. However, clinicians may hesitate to introduce mechanical ventilation for patients on liver transplantation waitlists because of poor prognosis. This study investigated the outcomes of intensive care and ventilation support therapy effects in patients with liver failure. Methods: This single‐center study retrospectively enrolled 32 consecutive patients with liver failure who were admitted to the intensive care unit from January 2014 to December 2020. The medical records were reviewed and analyzed retrospectively for Acute Physiologic and Chronic Health Evaluation (APACHE)‐II. The model for end‐stage liver disease scores, 90‐day mortality, and survival was assessed using the Kaplan–Meier method. Results: The average patient age was 45.5 ± 20.1 years, and 53% of patients were women. On intensive care unit admission, APACHE‐II and model for end‐stage liver disease scores were 20 and 28, respectively. Among 13 patients considered for liver transplantation, 4 received transplants. Thirteen patients (40.6%) were intubated and mechanically ventilated in the intensive care unit. The 90‐day mortality rate of patients with and without mechanical ventilation in the intensive care unit (13, 61.5% vs. 19, 47.4%, p = 0.4905) was similar. APACHE‐II score >21 was an independent predictor of mechanical ventilation requirement in patients with liver failure during intensive care unit stay. Conclusion: Although critically ill patients with liver failure are at risk of multiorgan failure with poor outcomes, mechanical ventilation did not negatively affect the 90‐day mortality or performance rates of liver transplantation. Clinicians should consider mechanical ventilation‐based life support in critically ill patients with liver failure who are awaiting liver transplantation. Key points: What's known As critically ill patients with liver failure have high mortality, clinicians hesitate to introduce mechanical ventilation for patients on liver‐transplantation waitlists because of the poor prognosis. What's new We aimed to clarify the management and treatment outcomes of patients with liver failure, especially those who needed mechanical ventilation. What the clinical implications of this study are Mechanical ventilation‐based life support is not an adverse prognostic factor for critically ill patients with liver failure who are on a waitlist for liver transplantation. Therefore, clinicians should unhesitatingly provide mechanical ventilation‐based life support in this patient group. [ABSTRACT FROM AUTHOR]

Published
2024
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14. Efficacy of Quantitative Susceptibility Mapping with Brain Surface Correction and Vein Removal for Detecting Increase Magnetic Susceptibility in Patients with Alzheimer’s Disease

Author

Yamaguchi, Akinori, primary, Kudo, Kohsuke, additional, Sato, Ryota, additional, Kawata, Yasuo, additional, Udo, Niki, additional, Matsushima, Masaaki, additional, Yabe, Ichiro, additional, Sasaki, Makoto, additional, Harada, Masafumi, additional, Matsukawa, Noriyuki, additional, Shirai, Toru, additional, Ochi, Hisaaki, additional, and Bito, Yoshitaka, additional

Published
2023
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16. High-count-rate 3He position-sensitive detector system: NEUNET-HCR

Author

Sato Setsuo, Seya Tomohiro, Oshita Hidetoshi, Kato Hideto, Hikida Noriyuki, Ishizawa Kazuya, Yamaguchi Akinori, and Matsuura Mitsugu

Subjects
Physics, QC1-999
Abstract

Highly reliable 3He gas detectors are most often used in neutron scattering experiments but have disadvantages such as low count rates and low position resolutions. In this study, a 3He gas detector system called NEUNET-HCR was developed, whose count rate is approximately 10 times that of the current NEUNET system, which was developed for a high position resolution with a low count rate. NEUNET-HCR achieved a maximum count rate of 535 kcps per detector, with a loss of approximately 30%. As the NEUNET-HCR system was developed based on the NEUNET system, various improvements were required to achieve the high count rate. Further, a high count rate was achieved in the NEUNET-HCR system without significantly degrading the position resolution.

Published
2020
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22. Efficacy of Quantitative Susceptibility Mapping with Brain Surface Correction and Vein Removal for Detecting Increase Magnetic Susceptibility in Patients with Alzheimer's Disease

Author

Yamaguchi, Akinori, Kudo, Kohsuke, Sato, Ryota, Kawata, Yasuo, Udo, Niki, Matsushima, Masaaki, Yabe, Ichiro, Sasaki, Makoto, Harada, Masafumi, Matsukawa, Noriyuki, Shirai, Toru, Ochi, Hisaaki, and Bito, Yoshitaka

Subjects
quantitative susceptibility mapping, brain surface correction, cerebral cortex, vein removal, Radiology, Nuclear Medicine and imaging, Alzheimer?s disease
Abstract

Purpose: Studies on quantitative susceptibility mapping (QSM) have reported an increase in magnetic susceptibilities in patients with Alzheimer's disease (AD). Despite the pathological importance of the brain surface areas, they are sometimes excluded in QSM analysis. This study aimed to reveal the efficacy of QSMMethods: Thirty-seven AD patients and 37 age- and sex-matched, cognitively normal (CN) subjects were included. A 3D-gradient echo sequence at 3T MRI was used to obtain QSM. QSM images were created with regularization enabled sophisticated harmonic artifact reduction for phase data (RESHARP) and constrained RESHARP with BSC and/or VR. We conducted ROI analysis between AD patients and CN subjects who did or did not undergo BSC and/or VR using a t-test, to compare the susceptibility values after gray matter weighting. Results: The susceptibility values in RESHARP without BSC were significantly larger in AD patients than in CN subjects in one region (precentral gyrus, 8.1 +/- 2.9 vs. 6.5 +/- 2.1 ppb) without VR and one region with VR (precentral gyrus, 7.5 +/- 2.8 vs. 5.9 +/- 2.0 ppb). Three regions in RESHARP with BSC had significantly larger susceptibilities without VR (precentral gyrus, 7.1 +/- 2.0 vs. 5.9 +/- 2.0 ppb; superior medial frontal gyrus, 5.7 +/- 2.6 vs. 4.2 +/- 3.1 ppb; putamen, 47,8 +/- 16.5 vs. 40.0 +/- 15.9 ppb). In contrast, six regions showed significantly larger susceptibilities with VR in AD patients than in CN subjects (precentral gyrus, 6.4 +/- 1.9 vs. 4.9 +/- 2.7 ppb; superior medial frontal gyrus, 5.3 +/- 2.7 vs. 3.7 +/- 3.3 ppb; orbitofrontal cortex, -2.1 +/- 2.7 vs. -3.6 +/- 3.2 ppb; parahippocampal gyrus, 0.1 +/- 3.6 vs. -1.7 +/- 3.7 ppb; putamen, 45.0 +/- 14.9 vs. 37.6 +/- 14.6 ppb; inferior temporal gyrus, -3.4 +/- 1.5 vs. -4.4 +/- 1.5 ppb).Conclusion: RESHARP with BSC and VR showed more regions of increased susceptibility in AD patients than in CN subjects. This study highlights the efficacy of this method in facilitating the diagnosis of AD.

Published
2022

31. Comparison of the factors associated with the short-term prognosis between elderly and non-elderly patients with anti-neutrophil cytoplasmic antibody-associated vasculitis: a retrospective observational study

Author

Harada, Makoto, primary, Yamaguchi, Akinori, additional, Sonoda, Kosuke, additional, Yamada, Yosuke, additional, Aomura, Daiki, additional, Kamimura, Yutaka, additional, Hashimoto, Koji, additional, Ichikawa, Tohru, additional, Kobayashi, Mamoru, additional, and Kamijo, Yuji, additional

Published
2021
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37. Correlation analysis between magnetic susceptibility in MRI and amyloid β in PET

Author

Sato, Ryota, primary, Kudo, Kohsuke, additional, Yamaguchi, Akinori, additional, Udo, Niki, additional, Matsushima, Masaaki, additional, Yabe, Ichiro, additional, Sasaki, Makoto, additional, Harada, Masafumi, additional, Matsukawa, Noriyuki, additional, Amemiya, Tomoki, additional, Kawata, Yasuo, additional, Bito, Yoshitaka, additional, Ochi, Hisaaki, additional, and Shirai, Toru, additional

Published
2020
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43. IC-P-139: A MULTICENTER STUDY OF THE CORRELATION BETWEEN THE QUANTITATIVE SUSCEPTIBILITY MAPPING OF MAGNETIC RESONANCE IMAGING AND AMYLOID POSITRON EMISSION TOMOGRAPHY

Author

Kudo, Kohsuke, primary, Sato, Ryota, additional, Yamaguchi, Akinori, additional, Udo, Niki, additional, Matsushima, Masaaki, additional, Yabe, Ichiro, additional, Sasaki, Makoto, additional, Harada, Masafumi, additional, Matsukawa, Noriyuki, additional, Shirai, Toru, additional, Kawata, Yasuo, additional, Ochi, Hisaaki, additional, and Bito, Yoshitaka, additional

Published
2019
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44. Twin-driven actuator with multi-layered disc magnetorheological fluid clutches for haptics.

Author

Kikuchi, Takehito, Abe, Isao, Nagata, Tomoya, Yamaguchi, Akinori, and Takano, Tetsumasa

Subjects
MAGNETORHEOLOGICAL fluids, HAPTIC devices, ACTUATORS, TORQUE control, FERROMAGNETIC materials, COMPOSITE materials, REMOTE control, RHEOMETERS
Abstract

Magnetorheological fluids are composite materials made of ferromagnetic particles, medium oils, and several types of additives. We have developed actuation systems for the fine haptic control of master–slave robots. In this study, we proposed a new structure of a magnetorheological fluid–based actuator suitable for haptic devices. For the basic structure of the actuator, we proposed a twin-driven magnetorheological fluid actuator using two multi-layered disc-type magnetorheological fluid clutches for haptics. We conducted performance measures for the magnetorheological fluid clutches for haptics with three commercially available magnetorheological fluids (i.e. 122EG, 132DG, and 140CG from Lord Corp.). The experimental results show that 132DG is a better material for force control. Then, we proposed two types of twin-driven magnetorheological fluid actuators (i.e. link type and belt type) and compared their performance. The results show that the averages of the time constant are 19.1 and 16.1 ms for the link type and belt type, respectively. Furthermore, the averages of torque error are 0.033 and 0.068 N m for the link type and belt type, respectively. However, the belt-type twin-driven magnetorheological fluid actuator is better if a large range of motion is required, while the link-type twin-driven magnetorheological fluid actuator is better if accurate torque control is required. [ABSTRACT FROM AUTHOR]

Published
2021
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45. A Screening Method for Cyanide in Blood by Dimethoxytriazinyl Derivatization-GC/MS.

Author

Yamaguchi, Akinori and Miyaguchi, Hajime

Subjects
*CYANIDES, *CLINICAL toxicology, *CYANIDE poisoning, *FORENSIC toxicology, *TRIAZINE derivatives, *BLOOD, *AQUEOUS solutions, *FALSE positive error
Abstract

A simple screening analysis of cyanide in blood has been developed, using 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM). DMTMM, a convenient reagent for dehydrocondensation, converted cyanide to 2-cyano-4,6-dimethoxy-1,3,5-triazine, the dimethoxytriazinyl derivative of cyanide. This reaction proceeded in whole blood samples after treatment with trichloroacetic acid, and in basic aqueous solution samples. Sufficient sensitivity was observed by the method using gas chromatography/mass spectrometry. Intra- and inter-day repeated analyses (0.05, 0.1, 0.25, 1 and 5 μg/mL, n  = 5) were performed and the accuracy and precision were within 20% for the lower limit of quantification (LLOQ) and within 15% for other concentrations. LLOQs for the aqueous solution and blood were 0.05 and 0.1 μg/mL, respectively, which are suitable for detecting cyanide poisoning. The limits of detection (signal-to-noise ratio ≥ 3) for aqueous solution and blood were 0.01 and 0.05 μg/mL, respectively. Interference from 13 other anions was tested and no false positive response was obtained, even in the case of thiocyanate, nitrite and nitrate, which are known to yield cyanide by acid treatment of blood. This method is practical because it uses readily available reagents and equipment and is sensitive enough for the rapid screening of cyanide poisoning in forensic and clinical toxicology. [ABSTRACT FROM AUTHOR]

Published
2021
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46. Calcitonin gene-related peptide and induction of hyperglycemia in conscious rats in vivo

Author

Yamaguchi, Akinori, Chiba, Tsutomu, Morishita, Tomoyuki, Nakamura, Akira, Inui, Tetsuya, Yamatani, Toshiyuki, Kadowaki, Seizo, Chihara, Kazuo, Fukase, Masaaki, and Fujita, Takuo

Subjects
Physiological aspects, Causes of, Glucose metabolism -- Physiological aspects, Hyperglycemia -- Causes of -- Physiological aspects
Abstract

The effect of calcitonin gene-related peptide (CGRP) on glucose metabolism was investigated in conscious and unrestrained rats in vivo. Intravenous injection of rat CGRP (5.67 and 0.567 nmol/kg) caused a [...]

Published
1990

48. High-count-rate 3He position-sensitive detector system: NEUNET-HCR.

Author

Ott, F., Menelle, A., Alba-Simionesco, C., Sato, Setsuo, Seya, Tomohiro, Oshita, Hidetoshi, Kato, Hideto, Hikida, Noriyuki, Ishizawa, Kazuya, Yamaguchi, Akinori, and Matsuura, Mitsugu

Subjects
GAS detectors, NEUTRON scattering, ELECTRIC fields, PULSE height analyzers, NEUTRON sources
Abstract

Highly reliable 3He gas detectors are most often used in neutron scattering experiments but have disadvantages such as low count rates and low position resolutions. In this study, a 3He gas detector system called NEUNET-HCR was developed, whose count rate is approximately 10 times that of the current NEUNET system, which was developed for a high position resolution with a low count rate. NEUNET-HCR achieved a maximum count rate of 535 kcps per detector, with a loss of approximately 30%. As the NEUNET-HCR system was developed based on the NEUNET system, various improvements were required to achieve the high count rate. Further, a high count rate was achieved in the NEUNET-HCR system without significantly degrading the position resolution. [ABSTRACT FROM AUTHOR]

Published
2020
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49. IC‐P‐194: DETECTION OF INCREASED MAGNETIC SUSCEPTIBILITIES IN THE CEREBRAL CORTEX IN PATIENTS WITH ALZHEIMER'S DISEASE: COMPARISON OF QUANTITATIVE SUSCEPTIBILITY MAPPING BETWEEN CONVENTIONAL AND BRAIN SURFACE CORRECTION METHOD

Author

Yamaguchi, Akinori, primary, Kudo, Kohsuke, additional, Sato, Ryota, additional, Kawata, Yasuo, additional, Udo, Niki, additional, Matsushima, Masaaki, additional, Yabe, Ichiro, additional, Shirai, Toru, additional, Ochi, Hisaaki, additional, and Bito, Yoshitaka, additional

Published
2018
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