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result(s) for
"Sugawara, Takeshi"
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Chemophoresis engine: A general mechanism of ATPase-driven cargo transport
2022
Cell polarity regulates the orientation of the cytoskeleton members that directs intracellular transport for cargo-like organelles, using chemical gradients sustained by ATP or GTP hydrolysis. However, how cargo transports are directly mediated by chemical gradients remains unknown. We previously proposed a physical mechanism that enables directed movement of cargos, referred to as chemophoresis. According to the mechanism, a cargo with reaction sites is subjected to a chemophoresis force in the direction of the increased concentration. Based on this, we introduce an extended model, the chemophoresis engine , as a general mechanism of cargo motion, which transforms chemical free energy into directed motion through the catalytic ATP hydrolysis. We applied the engine to plasmid motion in a ParABS system to demonstrate the self-organization system for directed plasmid movement and pattern dynamics of ParA-ATP concentration, thereby explaining plasmid equi-positioning and pole-to-pole oscillation observed in bacterial cells and in vitro experiments. We mathematically show the existence and stability of the plasmid-surfing pattern, which allows the cargo-directed motion through the symmetry-breaking transition of the ParA-ATP spatiotemporal pattern. We also quantitatively demonstrate that the chemophoresis engine can work even under in vivo conditions. Finally, we discuss the chemophoresis engine as one of the general mechanisms of hydrolysis-driven intracellular transport.
Journal Article
Hardware Performance Evaluation of Authenticated Encryption SAEAES with Threshold Implementation
2020
SAEAES is the authenticated encryption algorithm instantiated by combining the SAEB mode of operation with AES, and a candidate of the NIST’s lightweight cryptography competition. Using AES gives the advantage of backward compatibility with the existing accelerators and coprocessors that the industry has invested in so far. Still, the newer lightweight block cipher (e.g., GIFT) outperforms AES in compact implementation, especially with the side-channel attack countermeasure such as threshold implementation. This paper aims to implement the first threshold implementation of SAEAES and evaluate the cost we are trading with the backward compatibility. We design a new circuit architecture using the column-oriented serialization based on the recent 3-share and uniform threshold implementation (TI) of the AES S-box based on the generalized changing of the guards. Our design uses 18,288 GE with AES’s occupation reaching 97% of the total area. Meanwhile, the circuit area is roughly three times the conventional SAEB-GIFT implementation (6229 GE) because of a large memory size needed for the AES’s non-linear key schedule and the extended states for satisfying uniformity in TI.
Journal Article
Visual activities of daily living survey for retinitis pigmentosa
by
Baba, Takayuki
,
Pak, Kyongsun
,
Sugawara, Takeshi
in
Activities of Daily Living
,
Acuity
,
Adult
2024
Purpose
To gauge the value of low-vision-specific function and activities of daily living measures (LVFAM) in the assessment of Patient Reported Outcomes (PRO) of Retinitis Pigmentosa (RP).
Study design
Prospective observation study.
Methods
The May-July 2023 Visual activities of daily living (ADL) Survey of the low-vision-specific function and activities of daily living measure (LVFAM) was conducted on 15 RP patients attending our Ophthalmology outpatient clinic. We used the better corrected visual acuity, and the better Mean Deviation (MD) values of the central 10 degrees of Humphrey’s visual field as macular sensitivity, and examined the total scores after Rasch Analysis for each of the low-vision-specific function of Daily Living (LVFDL) and the low-vision-specific activities of Daily Living (LVADL) among LVFAM, as well as the relationship between the items.
Results
Age 26–78 (mean 60.8), 5 men and 10 women, corrected visual acuity of 0.01-1.0 (mean 0.45) in the better eye, macular sensitivity of 3.47-40.00 (mean 18.60) dB, mean 52.2 for LVFDL and 66.4 for LVADL. The correlations were positive for visual acuity and LVFDL and LVADL, and negative for macular sensitivity, LVFDL and LVADL. In addition, four items were scored 0 by at least 5 (33%) of the LVFDL respondents, and two items were scored 1 by at least 5 (33%) of the LVADL respondents, suggesting that the results differed by question items.
Conclusion
The LVFAM was useful not only for the total score but also for each question item in the development strategy of PROs in RP with no treatment.
Journal Article
Evaluation of the efficacy of empagliflozin in patients with preserved left ventricular ejection fraction undergoing transcatheter aortic valve implantation for aortic stenosis: protocol for a randomised, open-label, controlled study
by
Shoji, Mayumi
,
Kitahara, Hideki
,
Takaoka, Hiroyuki
in
Antidiabetics
,
Aortic stenosis
,
Aortic Valve Stenosis - physiopathology
2026
IntroductionHeart failure occasionally develops after transcatheter aortic valve implantation (TAVI) for severe aortic stenosis (AS), despite procedural success. Most cases present with mildly reduced or preserved left ventricular ejection fraction (LVEF), underscoring the role of diastolic dysfunction. Sodium-glucose cotransporter 2 (SGLT2) inhibitors have shown benefits across the heart failure spectrum, independent of LVEF. The purpose of this randomised controlled trial is to determine whether adding a SGLT2 inhibitor to conventional medications improves LV diastolic function in patients with preserved LVEF after TAVI.Methods and analysisThis study is a prospective, single-centre, open-label, randomised, parallel-group, two-arm trial enrolling patients with mildly reduced or preserved LVEF (≥40%) undergoing TAVI for severe AS. Participants will be randomised in a 1:1 ratio to receive either conventional medications plus empagliflozin or conventional medications alone. In the empagliflozin group, participants will receive conventional medical therapy plus empagliflozin 10 mg orally once daily, initiated 4 weeks after TAVI. Empagliflozin treatment will continue throughout the study period. Participants in the control group will receive conventional medications without empagliflozin. The primary endpoint is the change in E/e’, assessed by echocardiography from treatment initiation at 4 weeks post TAVI (day 1) to day 168 (week 24). Each group will include 50 patients, totalling 100 patients.Ethics and disseminationEthical approval for this study has been obtained from the Chiba University Hospital Certified Clinical Research Review Board (CRB0111-25).Trial registration numberjRCT1031250190.
Journal Article
Stochastic promoter activation affects Nanog expression variability in mouse embryonic stem cells
2014
Mouse embryonic stem cells (mESCs) are self-renewing and capable of differentiating into any of the three germ layers. An interesting feature of mESCs is the presence of cell-to-cell heterogeneity in gene expression that may be responsible for cell fate decisions. Nanog, a key transcription factor for pluripotency, displays heterogeneous expression in mESCs, via mechanisms that are not fully understood. To understand this variability, we quantitatively analyzed
Nanog
transcription and found that
Nanog
was both infrequently transcribed and transcribed in a pulsatile and stochastic manner. It is possible that such stochastic transcriptional activation could contribute to the heterogeneity observed in
Nanog
expression as “intrinsic noise.” To discriminate the effects of both intrinsic noise from other (extrinsic) noise on the expression variability of
Nanog
mRNA, we performed allele-specific single-molecule RNA fluorescent
in situ
hybridization in a reporter cell line and found that intrinsic noise contributed to approximately 45% of the total variability in
Nanog
expression. Furthermore, we found that
Nanog
mRNA and protein levels were well correlated in individual cells. These results suggest that stochastic promoter activation significantly affects the Nanog expression variability in mESCs.
Journal Article
Randomized clinical trial comparing intravitreal aflibercept combined with subthreshold laser to intravitreal aflibercept monotherapy for diabetic macular edema
2022
To compare the efficacy and safety of intravitreal aflibercept with three loading doses + pro re nata regimen combined with subthreshold laser application to that of IVA monotherapy on eyes with diabetic macular edema. This was a phase 4 clinical trial with a prospective, randomized, and parallel investigator-driven protocol. Patients with DME were randomly assigned to the IVA monotherapy group (n = 25) or the IVA + SL combination therapy group (n = 26). The main outcome measures were the number of IVA injections and the changes in the best-corrected visual acuity (BCVA) and the central retinal thickness (CRT) at the final evaluation at 96 weeks. The mean number of IVA injections in the monotherapy group was 5.86 ± 2.43 and it was 6.05 ± 2.73 in the IVA + SL group at 96 weeks, and this difference was not significant
(P
= 0.83). The differences in the mean changes of the CRT (
P
= 0.17) and the BCVA (
P
= 0.31) were also not significant between the two groups throughout the follow-up period. We conclude that adjunct of SL to anti-VEGF therapy does not reduce the number of necessary intravitreal injections.
Journal Article
Artificial intelligence-based model for predicting pulmonary arterial hypertension on chest x-ray images
by
Sakao, Seiichiro
,
Baba, Takayuki
,
Sekine, Ayumi
in
Algorithms
,
Artificial Intelligence
,
Care and treatment
2024
Background
Pulmonary arterial hypertension is a serious medical condition. However, the condition is often misdiagnosed or a rather long delay occurs from symptom onset to diagnosis, associated with decreased 5-year survival. In this study, we developed and tested a deep-learning algorithm to detect pulmonary arterial hypertension using chest X-ray (CXR) images.
Methods
From the image archive of Chiba University Hospital, 259 CXR images from 145 patients with pulmonary arterial hypertension and 260 CXR images from 260 control patients were identified; of which 418 were used for training and 101 were used for testing. Using the testing dataset for each image, the algorithm outputted a numerical value from 0 to 1 (the probability of the pulmonary arterial hypertension score). The training process employed a binary cross-entropy loss function with stochastic gradient descent optimization (learning rate parameter, α = 0.01). In addition, using the same testing dataset, the algorithm’s ability to identify pulmonary arterial hypertension was compared with that of experienced doctors.
Results
The area under the curve (AUC) of the receiver operating characteristic curve for the detection ability of the algorithm was 0.988. Using an AUC threshold of 0.69, the sensitivity and specificity of the algorithm were 0.933 and 0.982, respectively. The AUC of the algorithm’s detection ability was superior to that of the doctors.
Conclusion
The CXR image-derived deep-learning algorithm had superior pulmonary arterial hypertension detection capability compared with that of experienced doctors.
Journal Article
Evaluation of the efficacy of angiotensin receptor–neprilysin inhibitor in patients with aortic stenosis undergoing transcatheter aortic valve implantation: protocol for a randomised, open-label, controlled study
by
Inaba, Yosuke
,
Kitahara, Hideki
,
Kanda, Tomoyoshi
in
Adult cardiology
,
Aminobutyrates - administration & dosage
,
Aminobutyrates - therapeutic use
2025
IntroductionThere are a substantial number of patients developing heart failure after transcatheter aortic valve implantation (TAVI) for severe aortic stenosis (AS), even though AS has been successfully treated. The purpose of this randomised controlled trial was to determine whether the addition of an angiotensin receptor–neprilysin inhibitor (ARNI), sacubitril/valsartan, is superior to conventional medications in lowering N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels in patients undergoing TAVI for AS.Methods and analysisThe study design is a prospective, single-centre, open-label, randomised, parallel-group, two-arm study, in which participants will be randomised in a 1:1 ratio to receive either conventional medications plus ARNI or conventional medications only. In the ARNI group, if a patient was on an ACE inhibitor or angiotensin II receptor blocker before TAVI, it will be switched to ARNI 100 mg/day (50 mg two times per day) on the first postoperative day. If not, candesartan 4 mg/day will be started 1–2 days before TAVI, and switched to ARNI 100 mg/day on the first postoperative day. As the patient has tolerability to ARNI, dosage will be increased stepwise to 400 mg/day 2–4 weeks apart. ARNI will be continued until at least 6-month follow-up. In the control group, the patient will receive conventional medications. The primary endpoint is the serum NT-proBNP value at 6-month follow-up after TAVI. Each group includes 42 patients (84 total patients).Ethics and disseminationEthical approval for this study has been obtained from the Chiba University Hospital Certified Clinical Research Review Board (CRB3180015). The study is ongoing. Findings from this study will be disseminated through peer-reviewed publications and conference presentations.Trial registration numberThis trial has been registered on the Japan Registry of Clinical Trials: jRCT1031220344.
Journal Article
The Astrocyte-Targeted Therapy by Bushi for the Neuropathic Pain in Mice
by
Koizumi, Schuichi
,
Shibata, Keisuke
,
Shinozaki, Youichi
in
Activation
,
Analgesics
,
Analgesics - pharmacology
2011
There is accumulating evidence that the activation of spinal glial cells, especially microglia, is a key event in the pathogenesis of neuropathic pain. However, the inhibition of microglial activation is often ineffective, especially for long-lasting persistent neuropathic pain. So far, neuropathic pain remains largely intractable and a new therapeutic strategy for the pain is still required.
Using Seltzer model mice, we investigated the temporal aspect of two types of neuropathic pain behaviors, i.e., thermal hyperalgesia and mechanical allodynia, as well as that of morphological changes in spinal microglia and astrocytes by immunohistochemical studies. Firstly, we analyzed the pattern of progression in the pain behaviors, and found that the pain consisted of an \"early induction phase\" and subsequent \"late maintenance phase\". We next analyzed the temporal changes in spinal glial cells, and found that the induction and the maintenance phase of pain were associated with the activation of microglia and astrocytes, respectively. When Bushi, a Japanese herbal medicine often used for several types of persistent pain, was administered chronically, it inhibited the maintenance phase of pain without affecting the induction phase, which was in accordance with the inhibition of astrocytic activation in the spinal cord. These analgesic effects and the inhibition of astrocytic activation by Bushi were mimicked by the intrathecal injection of fluorocitrate, an inhibitor of astrocytic activation. Finally, we tested the direct effect of Bushi on astrocytic activation, and found that Bushi suppressed the IL-1β- or IL-18-evoked ERK1/2-phosphorylation in cultured astrocytes but not the ATP-evoked p38- and ERK1/2-phosphorylation in microglia in vitro.
Our results indicated that the activation of spinal astrocytes was responsible for the late maintenance phase of neuropathic pain in the Seltzer model mice and, therefore, the inhibition of astrocytic activation by Bushi could be a useful therapeutic strategy for treating neuropathic pain.
Journal Article