Publications by authors named "Takashi Kawakami"

Basic concepts and theoretical foundations of broken symmetry (BS) and post BS methods for strongly correlated electron systems (SCES) such as electron-transfer (ET) diradical, multi-center polyradicals with spin frustration are described systematically to elucidate structures, bonding and reactivity of the high-valent transition metal oxo bonds in metalloenzymes: photosystem II (PSII) and cytochrome c oxidase (CcO). BS hybrid DFT (HDFT) and DLPNO coupled-cluster (CC) SD(T) computations are performed to elucidate electronic and spin states of CaMnO cluster in the key step for oxygen evolution, namely S [S with Mn(IV) = O + Tyr161-O radical] state of PSII and P [Fe(IV) = O + HO-Cu(II) + Tyr161-O radical] step for oxygen reduction in CcO. The cycle of water oxidation catalyzed by the CaMnO cluster in PSII and the cycle of oxygen reduction catalyzed by the Cu-Fe-Fe-Cu cluster in CcO are examined on the theoretical grounds, elucidating similar concerted and/or stepwise proton transfer coupled electron transfer (PT-ET) processes for the four-electron oxidation in PSII and four-electron reduction in CcO.

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Background: The management of chronic thromboembolic pulmonary hypertension (CTEPH) has advanced significantly in recent years, thereby improving patient prognosis. However, the impact of cancer on the outcomes of patients with CTEPH under current treatment remains unclear. This study aimed to investigate the prevalence of cancer in patients with CTEPH and determine how comorbid cancer affects their prognosis and clinical course.

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Background: The contemporary outcome of balloon pulmonary angioplasty (BPA) and pulmonary endarterectomy (PEA) in patients with chronic thromboembolic pulmonary hypertension (CTEPH) are unclear.

Objectives: This study aimed to clarify the characteristics and outcomes of CTEPH patients treated with BPA and PEA in Japan.

Methods: Among 1,270 participants enrolled between 2018 and 2023 in the CTEPH AC (Chronic Thromboembolic Pulmonary Hypertension Anticoagulant) registry, a Japanese nationwide CTEPH registry, 369 treatment-naive patients (BPA strategy: n = 313; PEA strategy: n = 56) and 690 on-treatment patients (BPA strategy: n = 561; PEA strategy: n = 129) were classified according to the presence of prior reperfusion therapy.

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This research is based on a Systematic Evolution of Ligands by EXponential enrichment, also referred to as in vitro selection against the extracellular domain of human interleukin-17 receptor A (IL-17RA). Pull-down assay via quantitative polymerase chain reaction and chemiluminescence detection showed that the cloned RNA with the enriched sequence bound to human IL-17RA and inhibited the interaction between IL-17RA and human interleukin-17A (IL-17A). We also revealed that the newly discovered IL-17RA-binding RNA aptamer bound to cellular IL-17RA, inhibited the cellular IL-17RA/IL-17A interaction, and antagonized cellular IL-17A signaling.

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This paper reviews our historical developments of broken-symmetry (BS) and beyond BS methods that are applicable for theoretical investigations of metalloenzymes such as OEC in PSII. The BS hybrid DFT (HDFT) calculations starting from high-resolution (HR) XRD structure in the most stable S state have been performed to elucidate structure and bonding of whole possible intermediates of the CaMnO cluster (1) in the S (i = 0 ~ 4) states of the Kok cycle. The large-scale HDFT/MM computations starting from HR XRD have been performed to elucidate biomolecular system structures which are crucial for examination of possible water inlet and proton release pathways for water oxidation in OEC of PSII.

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Article Synopsis
  • * The article discusses the broken-symmetry (BS) method and its applications, including the development of additional chemical indices that link BS methods with advanced methods, emphasizing the role of natural orbitals in evaluating chemical reactions.
  • * Finally, it highlights the significance of isolobal and isospin analogies in elucidating the reactivity of various compounds, incorporating recent advancements in computational techniques like hybrid DFT and quantum computing to validate earlier theoretical models.
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The analysis of the diradical state of functional open-shell molecules is important for understanding their physical properties and chemical reactivity. The diradical character is an important factor in the functional elucidation and design of open-shell molecules. In recent years, attempts have been made to immobilise functional open-shell molecules on surfaces to form devices.

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Article Synopsis
  • A study was done to find out how often gene changes related to cholesterol levels happen in young patients with heart disease.
  • Out of 52 patients studied, only one had a bad gene change that could lead to health problems, while another had uncertain gene variations.
  • The findings suggest that since it's hard to spot familial hypercholesterolemia (a condition that raises cholesterol in families) by looking at symptoms alone, genetic testing could help find hidden risks and alert family members.
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Background: Chronic thromboembolic pulmonary hypertension (CTEPH) requires lifelong anticoagulation. Long-term outcomes of CTEPH under current anticoagulants are unclear.

Objectives: The CTEPH AC registry is a prospective, nationwide cohort study comparing the safety and effectiveness of direct oral anticoagulants (DOACs) and warfarin for CTEPH.

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Failure of the right ventricle plays a critical role in any type of heart failure. However, the mechanism remains unclear, and there is no specific therapy. Here, we show that the right ventricle predominantly expresses alternative complement pathway-related genes, including Cfd and C3aR1.

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Lead-free halide perovskites have gained attention in recent years as viable materials with more distinctive characteristics than conventional semiconductor materials. Lead-free CsBiI colloidal perovskite nanocrystal is chosen to eliminate its single-phase synthesis difficulty and implement the material in bioimaging applications. Nanostructured CsBiI perovskite composites were coated with a thin coating of SiO by an tetraethyl orthosilicate/(3-aminopropyl)trimethoxysilane injection growth method to enhance their stability in aqueous medium and biocompatibility.

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Background: Treatment options for patients with chronic thromboembolic pulmonary hypertension ineligible for pulmonary endarterectomy (inoperable CTEPH) include balloon pulmonary angioplasty (BPA) and riociguat. However, these two treatment options have not been compared prospectively. We aimed to compare the safety and efficacy of BPA and riociguat in patients with inoperable CTEPH.

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Interaction between the pro-inflammatory cytokine interleukin-23 (IL-23) and IL-23 receptor (IL-23R) is related to the development of inflammatory autoimmune diseases such as psoriasis, inflammatory bowel disease, and Crohn's disease. In this study, we conducted systematic evolution of ligands by exponential enrichment (SELEX) for in vitro selection against human IL-23 and observed RNA sequence enrichment in the final SELEX round. IL-23-pull-down assay by chemiluminescence detection and fluorescence imaging demonstrated that SELEX-enriched RNA clone bound to IL-23.

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Interleukin-5 (IL-5) is a type 2 cytokine involved in various allergic diseases, including severe eosinophilic asthma. In this study, we performed directed evolution against human IL-5 using systematic evolution of ligands by exponential enrichment (SELEX) from multiple mRNA-displayed peptide libraries. Peptide libraries were prepared with Escherichia coli-based reconstituted cell-free transcription and translation coupling system (PURE system) and spontaneously cyclized using multiple intramolecularly thiol-reactive benzoic acid-derived linkers, which were ribosomally incorporated through genetic code expansion.

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We report novel, ribosomally incorporatable, and intramolecularly cysteine-reactive fluorobenzoic acid-derived linkers for SELEX of mRNA-displayed unnatural peptides, which spontaneously cyclized intramolecular nucleophilic aromatic substitutions forming thioethers. With this strategy we identified several novel PCSK9-binding peptides.

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Aim: The purpose of this study was to automatically extract myocardial regions from transaxial single-photon emission computed tomography (SPECT) images using deep learning to reduce the effects of extracardiac activity, which has been problematic in cardiac nuclear imaging.

Method: Myocardial region extraction was performed using two deep neural network architectures, U-Net and U-Net ++, and 694 myocardial SPECT images manually labeled with myocardial regions were used as the training data. In addition, a multi-slice input method was introduced during the learning session while taking the relationships to adjacent slices into account.

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Chemical indices are effective tools for examining the functions and reactivities of stable radical species. In this study, we formulated an approximation to estimate chemical indices using electron density. Theoretical investigations using the developed scheme revealed that surface interactions can tune chemical indices and that the diradical character was enhanced by weak adsorption onto ionic solids with charge-dipole interactions.

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Instrumental activities of daily living (IADL) are significantly related to quality of life and mortality among individuals with heart disease. However, few reports have examined IADL in persons with chronic thromboembolic pulmonary hypertension (CTEPH). The aim of this study was to clarify factors related to IADL in persons with CTEPH.

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Article Synopsis
  • Extensive balloon pulmonary angioplasty (BPA) has been shown to improve hemodynamics in patients with chronic thromboembolic pulmonary hypertension (CTEPH), but its effects on exercise tolerance and quality of life (QOL) are less understood.
  • A study involving 22 CTEPH patients demonstrated significant improvements in peak oxygen uptake (VO2) and physical component summary (PCS) scores after BPA, while mental component summary scores did not change.
  • Factors such as age and initial VO2 levels helped predict which patients would see improvements in exercise capacity and physical QOL after the procedure.
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Introduction: Pulmonary hypertension (PH) is a chronic and progressive disease. While prognoses have improved, PH patients still experience side effects and activity restrictions. Accordingly, the key questions asked by this study are 'How many PH patients have depression/anxiety symptoms?' and 'Is there a difference in the symptoms and distress factors between pulmonary arterial hypertension (PAH) and chronic thromboembolic PH (CTEPH) patients, and how are they experiencing distress?'

Methods: A mixed-methods study was conducted to collect and analyse quantitative and qualitative data.

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Background: New-onset atrial tachyarrhythmia (ATA) often develops after atrial septal defect (ASD) closure. Its development raises some potential concerns such as stroke and bleeding complications caused by anticoagulant therapy and limited access to the left atrium for catheter ablation. Although it is essential to identify the risk factors of new-onset ATA, few studies have examined these factors.

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The interaction of human epidermal growth factor receptor 3 (HER3) and heregulin (HRG) is involved in resistance to human epidermal growth factor receptor 2 (HER2)-targeted cancer treatment, such as therapies using anti-HER2 monoclonal antibody. Therefore, inhibition of the HER3/HRG interaction is potentially valuable therapeutic target for cancer treatment. In this study, we used in vitro selection, also known as systematic evolution of ligands by exponential enrichment (SELEX) against the extracellular domain of human HER3, and discovered a novel RNA aptamer.

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