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result(s) for
"Yamada, Makito"
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A New Tetracyclic Bromopyrrole-Imidazole Derivative through Direct Chemical Diversification of Substances Present in Natural Product Extract from Marine Sponge Petrosia (Strongylophora) sp
by
Arisawa, Mitsuhiro
,
Yamada, Makito
,
Sirimangkalakitti, Natchanun
in
Animals
,
Antifungal agents
,
bromopyrrole imidazole alkaloid
2022
Chemical diversification of substances present in natural product extracts can lead to a number of natural product-like compounds with a better chance of desirable bioactivities. The aim of this work was to discover unprecedented chemical conversion and produce new compounds through a one-step reaction of substances present in the extracts of marine sponges. In this report, a new unnatural tetracyclic bromopyrrole-imidazole derivative, rac-6-OEt-cylindradine A (1), was created from a chemically diversified extract of the sponge Petrosia (Strongylophora) sp. We also confirmed that 1 originated from naturally occurring (-)-cylindradine A (2) via a new reaction pattern. Moreover, (-)-dibromophakellin (3) and 4,5-dibromopyrrole-2-carboxylic acid (4), as well as 2, were reported herein for the first time in this genus. Studies on the possible reaction mechanism and bioactivities were also conducted. The results indicate that the direct chemical diversification of substances present in natural product extracts can be a speedy and useful strategy for the discovery of new compounds.
Journal Article
A New Tetracyclic Bromopyrrole-Imidazole Derivative through Direct Chemical Diversification of Substances Present in Natural Product Extract from Marine Sponge IPetrosia/I sp
by
Arisawa, Mitsuhiro
,
Yamada, Makito
,
Sirimangkalakitti, Natchanun
in
Biological products
,
Chemical properties
,
Drug discovery
2022
Chemical diversification of substances present in natural product extracts can lead to a number of natural product-like compounds with a better chance of desirable bioactivities. The aim of this work was to discover unprecedented chemical conversion and produce new compounds through a one-step reaction of substances present in the extracts of marine sponges. In this report, a new unnatural tetracyclic bromopyrrole-imidazole derivative, rac-6-OEt-cylindradine A (1), was created from a chemically diversified extract of the sponge Petrosia (Strongylophora) sp. We also confirmed that 1 originated from naturally occurring (-)-cylindradine A (2) via a new reaction pattern. Moreover, (-)-dibromophakellin (3) and 4,5-dibromopyrrole-2-carboxylic acid (4), as well as 2, were reported herein for the first time in this genus. Studies on the possible reaction mechanism and bioactivities were also conducted. The results indicate that the direct chemical diversification of substances present in natural product extracts can be a speedy and useful strategy for the discovery of new compounds.
Journal Article
Transmissibility of COVID-19 depends on the viral load around onset in adult and symptomatic patients
2020
To investigate the relationship between viral load and secondary transmission in novel coronavirus disease 2019 (COVID-19).
Epidemiological and clinical data were obtained from immunocompetent laboratory-confirmed patients with COVID-19 who were admitted to and/or from whom viral loads were measured at Toyama University Hospital. Using a case-control approach, index patients who transmitted the disease to at least one other patient were analysed as \"cases\" (index patients) compared with patients who were not the cause of secondary transmission (non-index patients, analysed as \"controls\"). The viral load time courses were assessed between the index and non-index symptomatic patients using non-linear regression employing a standard one-phase decay model.
In total, 28 patients were included in the analysis. Median viral load at the initial sample collection was significantly higher in symptomatic than in asymptomatic patients and in adults than in children. Among symptomatic patients (n = 18), non-linear regression models showed that the estimated viral load at onset was higher in the index than in the non-index patients (median [95% confidence interval]: 6.6 [5.2-8.2] vs. 3.1 [1.5-4.8] log copies/μL, respectively). In adult (symptomatic and asymptomatic) patients (n = 21), median viral load at the initial sample collection was significantly higher in the index than in the non-index patients (p = 0.015, 3.3 vs. 1.8 log copies/μL, respectively).
High nasopharyngeal viral loads around onset may contribute to secondary transmission of COVID-19. Viral load may help provide a better understanding of why transmission is observed in some instances, but not in others, especially among household contacts.
Journal Article
Non-maintenance intravesical Bacillus Calmette–Guérin induction therapy with eight doses in patients with high- or highest-risk non-muscle invasive bladder cancer: a retrospective non-randomized comparative study
by
Nishiyama, Hiroyuki
,
Yamada, Takeshi
,
Tomida, Ryotaro
in
Adjuvants, Immunologic - administration & dosage
,
Administration, Intravesical
,
Aged
2021
Background
To explore possible solutions to overcome chronic Bacillus Calmette–Guérin (BCG) shortage affecting seriously the management of non-muscle invasive bladder cancer (NMIBC) in Europe and throughout the world, we investigated whether non-maintenance eight-dose induction BCG (iBCG) was comparable to six-dose iBCG plus maintenance BCG (mBCG).
Methods
This observational study evaluated 2669 patients with high- or highest-risk NMIBC who treated with iBCG with or without mBCG during 2000–2019. The patients were classified into five groups according to treatment pattern: 874 (33%) received non-maintenance six-dose iBCG (Group A), 405 (15%) received six-dose iBCG plus mBCG (Group B), 1189 (44%) received non-maintenance seven−/eight-dose iBCG (Group C), 60 (2.2%) received seven−/eight-dose iBCG plus mBCG, and 141 (5.3%) received only ≤5-dose iBCG. Recurrence-free survival (RFS), progression-free survival, and cancer-specific survival were estimated and compared using Kaplan–Meier analysis and the log-rank test, respectively. Propensity score-based one-to-one matching was performed using a multivariable logistic regression model based on covariates to obtain balanced groups. To eliminate possible immortal bias, 6-, 12-, 18-, and 24-month conditional landmark analyses of RFS were performed.
Results
RFS comparison confirmed that mBCG yielded significant benefit following six-dose iBCG (Group B) in recurrence risk reduction compared to iBCG alone (groups A and C) before (
P
< 0.001 and
P
= 0.0016, respectively) and after propensity score matching (
P
= 0.001 and
P
= 0.0074, respectively). Propensity score-matched sequential landmark analyses revealed no significant differences between groups B and C at 12, 18, and 24 months, whereas landmark analyses at 6 and 12 months showed a benefit of mBCG following six-dose iBCG compared to non-maintenance six-dose iBCG (
P
= 0.0055 and
P
= 0.032, respectively). There were no significant differences in the risks of progression and cancer-specific death in all comparisons of the matched cohorts.
Conclusions
Although non-maintenance eight-dose iBCG was inferior to six-dose iBCG plus mBCG, the former might be an alternative remedy in the BCG shortage era. To overcome this challenge, further investigation is warranted to confirm the real clinical value of non-maintenance eight-dose iBCG.
Journal Article
Delayed neutralizing antibody response in the acute phase correlates with severe progression of COVID-19
by
Fukui, Yasutaka
,
Yoshida, Yoshihiro
,
Takegoshi, Yusuke
in
631/250/2152/2153/1291
,
631/326/596/4130
,
692/699/255/2514
2021
Adaptive immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) dynamics remain largely unknown. The neutralizing antibody (NAb) levels in patients with coronavirus disease 2019 (COVID-19) are helpful for understanding the pathology. Using SARS-CoV-2 pseudotyped virus, serum sample neutralization values in symptomatic COVID-19 patients were measured using the chemiluminescence reduction neutralization test (CRNT). At least two sequential serum samples collected during hospitalization were analyzed to assess NAbs neutralizing activity dynamics at different time points. Of the 11 patients, four (36.4%), six (54.5%), and one (9.1%) had moderate, severe, and critical disease, respectively. Fifty percent neutralization (N50%-CRNT) was observed upon admission in 90.9% (10/11); all patients acquired neutralizing activity 2–12 days after onset. In patients with moderate disease, neutralization was observed at earliest within two days after symptom onset. In patients with severe-to-critical disease, neutralization activity increased, plateauing 9–16 days after onset. Neutralization activity on admission was significantly higher in patients with moderate disease than in patients with severe-to-critical disease (relative % of infectivity, 6.4% vs. 41.1%;
P
= .011). Neutralization activity on admission inversely correlated with disease severity. The rapid NAb response may play a crucial role in preventing the progression of COVID-19.
Journal Article
Low pre-infection levels of neutralizing antibody in breakthrough infections after bivalent BA.4–5 vaccine and practical application of dried blood spots
by
Ezaki, Masayoshi
,
Niimi, Hideki
,
Yoshida, Yoshihiro
in
Adult
,
Allergy and Immunology
,
Antibodies
2024
The level of neutralizing antibodies required to confer protection against COVID-19 breakthrough infections (BIs) is unclear, and the ability to know the immune status of individuals against the rapidly changing endemic variants is limited. We assessed longitudinal serum anti-RBD antibody levels and neutralizing activities (NTs) against Omicron BA.5 and XBB.1.5 in healthcare workers following the fourth monovalent and fifth bivalent BA.4–5 vaccines. The occurrence of BIs was also followed, and pre-infection antibody levels were compared between patients who developed BI and those who did not. In addition, we collected whole blood samples on the same day as the sera and stored them on filter papers (nos. 545, 590, and 424) for up to two months, then measured their NTs using dried blood spots (DBS) eluates, and compared them with the NTs in paired sera. Pre-infection levels of NTs were lower in patients who developed BI than those who did not, but the anti-RBD antibody levels were not different between them. The NTs below 50 % using 200-fold diluted sera might be one of the indicators of high risk for COVID-19 BI. However, the NTs against XBB.1.5 at 6 months after the fifth dose of bivalent BA.4–5 vaccine were lower than this threshold in almost half of infection-naïve participants. NTs measured using DBS eluates were strongly correlated with those measured using paired sera, but the time and temperature stability varied with the type of filter paper; no. 545 filter paper was found to most suitable for NT evaluation.
Journal Article
High interleukin-6 levels induced by COVID-19 pneumonia correlate with increased circulating follicular helper T cell frequency and strong neutralization antibody response in the acute phase of Omicron breakthrough infection
2024
Acute immune responses to coronavirus disease 2019 (COVID-19) are influenced by variants, vaccination, and clinical severity. Thus, the outcome of these responses may differ between vaccinated and unvaccinated patients and those with and without COVID-19-related pneumonia. In this study, these differences during infection with the Omicron variant were investigated.
A total of 67 patients (including 47 vaccinated and 20 unvaccinated patients) who were hospitalized within 5 days after COVID-19 symptom onset were enrolled in this prospective observational study. Serum neutralizing activity was evaluated using a pseudotyped virus assay and serum cytokines and chemokines were measured. Circulating follicular helper T cell (cTfh) frequencies were evaluated using flow cytometry.
Twenty-five patients developed COVID-19 pneumonia on hospitalization. Although the neutralizing activities against wild-type and Delta variants were higher in the vaccinated group, those against the Omicron variant as well as the frequency of developing pneumonia were comparable between the vaccinated and unvaccinated groups. IL-6 and CXCL10 levels were higher in patients with pneumonia than in those without it, regardless of their vaccination status. Neutralizing activity against the Omicron variant were higher in vaccinated patients with pneumonia than in those without it. Moreover, a distinctive correlation between neutralizing activity against Omicron, IL-6 levels, and cTfh proportions was observed only in vaccinated patients.
The present study demonstrates the existence of a characteristic relationship between neutralizing activity against Omicron, IL-6 levels, and cTfh proportions in Omicron breakthrough infection.
Journal Article
First Passive Permittivity Measurement of Lunar Regolith Simulant at Terahertz Band
by
Miyamoto, Hideaki
,
Toida, Airi
,
Takemura, Tomohiro
in
Experimental data
,
Lunar regolith
,
Lunar science
2025
This study presents the first passive measurements of the relative polarization ratio (RPR) and apparent bulk permittivity (ABP) of lunar regolith simulants at approximately 280 GHz. We prepare anorthositic and basaltic simulants with both optically flat surfaces and surfaces with roughness equivalent to typical lunar surface roughness represented by the Chang’E-4 landing site and conduct passive measurements to verify whether the RPR and ABP follow Fresnel’s law. For flat-surfaced samples, the results confirm that the relationship between RPR, incidence angle, and ABP is consistent with the Fresnel-derived relationship. The ABP values are 1.91 and 2.40 for the anorthositic and basaltic simulant, respectively. Importantly, even for rough-surfaced samples, which incorporate surface scattering effects, the results demonstrate that the relationship between RPR, incidence angle, and ABP remains consistent with the Fresnel-derived relationship. This is the first experimental confirmation that passive observation can estimate the ABP of lunar regolith using the Fresnel-derived relationship, even with lunar surface roughness. Furthermore, the permittivity differences originating from the inherent bulk density and chemical composition of the samples are preserved despite the surface roughness. These findings suggest that passive polarimetric remote sensing, such as that employed by the TSUKIMI mission, can effectively estimate the ABP of the lunar surface and provide insights into identifying regions with potential for resource exploration.
Journal Article
Population Pharmacokinetic Analysis and Modelling of Serum Uric Acid Dynamics in Patients Treated with Favipiravir
2026
Background: Hyperuricemia is an adverse effect frequently observed during favipiravir treatment. The time course, from uric acid elevation to recovery, and quantitative relationship between drug exposure and changes in serum uric acid levels remain insufficiently characterized. We investigated the pharmacodynamic mechanism of uric acid elevation and described its time course by population pharmacokinetic and pharmacodynamic modelling. Methods: Patients who received favipiravir for coronavirus disease 2019 or severe fever with thrombocytopenia syndrome were retrospectively evaluated. The pharmacokinetics of favipiravir were described by a one-compartment model with first-order absorption and elimination. Metabolite concentrations were predicted based on previously reported values. Changes in serum uric acid levels were described by a turnover model with zero-order production and first-order elimination. The drug effect was implemented as inhibition of the uric acid elimination process. Simulations based on the final model were performed for 10 consecutive days after the clinical regimen, with a 21-day follow-up. Results: The final model supported the inhibition of uric acid elimination by favipiravir and its metabolite. Regarding simulations, serum uric acid levels reached a median peak of 6.93 mg/dL at 6.7 days after treatment initiation and returned to pre-treatment levels within 4.0 days after treatment discontinuation. Conclusions: This combined population pharmacokinetic and pharmacodynamic turnover model quantified favipiravir-associated increases in serum uric acid levels and showed a transient profile with rapid recovery after drug discontinuation. These findings underscore the need for monitoring serum uric acid levels during favipiravir treatment, particularly in patients at a higher risk of gout.
Journal Article
Future Perspective for ALK-Positive Anaplastic Large Cell Lymphoma with Initial Central Nervous System (CNS) Involvement: Could Next-Generation ALK Inhibitors Replace Brain Radiotherapy for the Prevention of Further CNS Relapse?
by
Yoshikawa, Tetsushi
,
Tanaka, Makito
,
Yamada, Seiji
in
alectinib
,
ALK inhibitor
,
Anaplastic large-cell lymphoma
2023
Central nervous system (CNS) involvement in anaplastic large cell lymphoma (ALCL) at diagnosis is rare and leads to poor prognosis with the use of the standard ALCL99 protocol alone. CNS-directed intensive chemotherapy, such as an increased dose of intravenous MTX, increased dose of dexamethasone, intensified intrathecal therapy, and high-dose cytarabine, followed by cranial irradiation, has been shown to improve survival in this population. In this paper, the authors describe a 14-year-old male with an intracranial ALCL mass at onset who received CNS-directed chemotherapy followed by 23.4 Gy of whole-brain irradiation. After the first systemic relapse, the CNS-penetrating ALK inhibitor, alectinib, was applied; it has successfully maintained remission for 18 months without any adverse events. CNS-penetrating ALK inhibitor therapy might prevent CNS relapse in pediatric ALK-positive ALCL. Next-generation ALK inhibitors could be introduced as a promising treatment option, even for primary ALCL with CNS involvement, which could lead to the omission of cranial irradiation and avoid radiation-induced sequalae. Further evidence of CNS-penetrating ALK inhibitor combined therapy for primary ALK-positive ALCL is warranted to reduce radiation-induced sequalae in future treatments.
Journal Article