Publications by authors named "Megumi Kato"

Correction for 'Establishment and characterization of noro-VLP measurement by digital ELISA' by Takema Hasegawa , , 2024, , 7089-7094, https://doi.org/10.1039/D4AY01012D.

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Highly sensitive viral analytical techniques are essential tools for preventing the spread of infections. In this study, we established a digital enzyme-linked immunosorbent assay (ELISA) system to quantify norovirus proteins with high sensitivity. We used norovirus-like particles (noro-VLPs) as a surrogate for norovirus and constructed two digital ELISA systems using two different antibody pairs.

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Reverse transcription-digital PCR (RT-dPCR) is attracting attention as a method that enables SI-traceable RNA quantification without calibration, but its accuracy and bias have not been thoroughly studied. In this study, the accurate quantification of RNA by the RT-dPCR method was investigated using NMIJ CRM 6204-b, an RNA certified reference material whose certified value was assigned by orthogonal chemical measurement methods. Moreover, a two-step RT-dPCR method was adopted to examine in detail the conditions for the RT reaction process, which was expected to be the major uncertainty component in the RT-dPCR measurement.

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Emery-Dreifuss muscular dystrophy (EDMD), caused by mutations in genes encoding nuclear envelope proteins, is clinically characterized by muscular dystrophy, early joint contracture, and life-threatening cardiac abnormalities. To elucidate the pathophysiological mechanisms underlying striated muscle involvement in EDMD, we previously established a murine model with mutations in Emd and Lmna (Emd/Lmna; EH), and reported exacerbated skeletal muscle phenotypes and no notable cardiac phenotypes at 12 weeks of age. We predicted that lack of emerin in Lmna mice causes an earlier onset and more pronounced cardiac dysfunction at later stages.

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To facilitate the development of effective viral detection techniques, a positive control material is required for validating their quantitative performance. Inactivated viruses serve as viable control materials, as they can be handled without the constraints of biohazard safety facilities. However, inactivation alters the structure of viral component molecules, necessitating the selection of inactivation methods that have minimal effects on the target molecules relevant to molecular detection techniques.

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Salinity stress can greatly reduce seed production because plants are especially sensitive to salt during their reproductive stage. Here, we show that the sodium ion transporter AtHKT1;1 is specifically expressed around the phloem and xylem of the stamen in to prevent a marked decrease in seed production caused by salt stress. The stamens of AtHKT1;1 mutant under salt stress overaccumulate Na, limiting their elongation and resulting in male sterility.

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A single-molecule assay (SiMoA) using a digital enzyme-linked immunosorbent assay (ELISA) has been attracting attention as a promising method that can detect viruses with ultra-high sensitivity. However, the quantitative application of digital ELISA has not been adequately reported. Therefore, in this study, we first evaluated the linearity and sensitivity of digital ELISA using a Certified Reference Material of C-reactive protein (NMIJ CRM 6201-c) as a quality control material.

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Rationale: Native mass spectrometry (MS) is an analytical technique used to determine the molecular mass of protein complexes without cross-linking. Size exclusion chromatography (SEC) coupled with native MS using conventional electrospray ionization (ESI) has been reported to allow online buffer exchange. To detect a wide variety of protein complexes without a collapse in the ionization process, it is important to build an online system that enables robust analysis with a low flow rate.

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The precise quantification of KRAS single nucleotide variant (SNV) is critical for the treatment and prognosis of lung and colorectal cancer. Validation of digital PCR (dPCR) as a method for accurate quantification of KRAS SNV has great clinical importance. An international co-validation on absolute quantification of KRAS SNV by dPCR was conducted among three national measurement institutes (NMIs) from China (NIM), South Korea (KRISS), and Japan (NMIJ).

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The practicality of the finite-difference time-domain (FDTD) method was confirmed by comparing head-related transfer functions obtained from a three-dimensional (3D) digital model of a bat (Rhinolophus ferrumequinum nippon) head with acoustic experiments using a 3D printed physical model. Furthermore, we simulated the auditory directionality using a 3D digital model that was modified based on the pinna movement of a bat during echolocation and found that the alternating movements of the left and right pinna result in a binaural sound pressure difference for vertical sources. Using the FDTD method, suitable for simulating acoustics in large spaces, we could analyze in detail the binaural echoes that bats receive and the acoustic cues they use for echolocation.

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Article Synopsis
  • Monoclonal antibodies are the leading type of biopharmaceuticals, but their development requires a reliable reference material for quality control.
  • A new humanized IgG1κ monoclonal antibody reference material, RM 6208-a, was created by Japan's National Metrology Institute for precise analysis and comparison of antibody tests.
  • This reference material includes detailed data on antibody concentration and other properties, aiding laboratories in standardizing measurements and ensuring the quality of monoclonal antibodies.
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Stomatal movement is indispensable for plant growth and survival in response to environmental stimuli. Cytosolic Ca elevation plays a crucial role in ABA-induced stomatal closure during drought stress; however, to what extent the Ca movement across the plasma membrane from the apoplast to the cytosol contributes to this process still needs clarification. Here the authors identify (-)-catechin gallate (CG) and (-)-gallocatechin gallate (GCG), components of green tea, as inhibitors of voltage-dependent K channels which regulate K fluxes in Arabidopsis thaliana guard cells.

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Article Synopsis
  • Adult T-cell leukemia/lymphoma (ATL) cells express a receptor called TNF receptor type-2 (TNFR2) and release its soluble form (sTNFR2) into the bloodstream, which is significantly elevated in patients with acute ATL.
  • The study investigated plasma sTNFR2 levels in a large group of ATL patients and asymptomatic carriers of the HTLV-1 virus, comparing them to other candidate biomarkers like sCD25, sOX40, and IL-10.
  • Results showed that higher sTNFR2 levels are strongly linked to acute ATL diagnosis and could be used alongside other biomarkers for better diagnostic accuracy.
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Chronic magnesium (Mg) deficiency induces and exacerbates various cardiovascular diseases. We previously investigated the mechanisms underlying decline in cardiac function caused by chronic Mg deficiency and the effectiveness of Mg supplementation on this decline using the Langendorff-perfused isolated mouse heart model. Herein, we used the Langendorff-perfused isolated rat heart model to demonstrate the chronic Mg-deficient rats (Mg-deficient group) had lower the heart rate (HR) and left ventricular pressure (LVDP) than rats with normal Mg levels (normal group).

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Lactononadecapeptide (LNDP; NIPPLTQTPVVVPPFLQPE) is a memory-improving peptide. The current study aimed to determine the effects of a single dose of tablets containing LNDP on cognitive function in healthy Japanese men aged 30-59 years. A randomized, double-blind, cross-over, placebo-controlled trial was conducted in participants randomly assigned to receive LNDP or placebo tablets.

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Adult T-cell leukemia/lymphoma (ATL) is a human T-cell leukemia virus type 1 (HTLV-1)-associated T-cell malignancy with generally poor prognosis. Although only ∼5% of HTLV-1 carriers progress to ATL, early diagnosis is challenging because of the lack of ATL biomarkers. In this study, we analyzed blood plasma profiles of asymptomatic HTLV-1 carriers (ACs); untreated ATL patients, including acute, lymphoma, smoldering, and chronic types; and ATL patients in remission.

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Over two decades, the Organic Analysis Working Group (OAWG) of the Consultative Committee for Amount of Substance: Metrology in Chemistry and Biology (CCQM) has organized a number of comparisons for clinically relevant small molecule organic biomarkers. The aim of the OAWG community is to be part of the coordinated international movement towards accuracy and comparability of clinical measurements that will, in turn, minimize the wastage of repeat testing and unnecessary therapy to create a sustainable healthcare industry. International and regional directives/requirements on metrological traceability of calibrators and control materials are in place.

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There is no standard systemic therapy for unresectable cutaneous squamous cell carcinoma (ucSCC), although various chemotherapy regimens have been reported. In our department, concurrent chemoradiotherapy (CCRT) for ucSCC resulted in a 1-year survival rate similar to that of resectable cutaneous squamous cell carcinoma (cSCC). Treatment involves continued chemotherapy after CCRT.

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Laminopathies are tissue-selective diseases that affect differently in organ systems. Mutations in nuclear envelopes, emerin (Emd) and lamin A/C (Lmna) genes, cause clinically indistinguishable myopathy called Emery-Dreifuss muscular dystrophy (EDMD) and limb-girdle muscular dystrophy. Several murine models for EDMD have been generated; however, emerin-null (Emd) mice do not show obvious skeletal and cardiac muscle phenotypes, and Lmna H222P/H222P mutant (H222P) mice show only a mild phenotype in skeletal muscle when they already have severe cardiomyopathy.

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Here, we describe an amino acid analysis that is based on the use of hydrophilic interaction liquid chromatography coupled with isotope dilution mass spectrometry for the accurate quantification of underivatized amino acids from hydrolyzed peptide/protein. Twelve underivatized amino acids were separated and detected during an 88-min runtime. The absolute limits of detection and limits of quantification (on column) of the four amino acids (isoleucine, phenylalanine, proline, and valine) were in the range of 6-80 and 20-200 fmol, respectively.

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Pyrexia is the most common adverse event in patients with melanoma or other solid organ malignancies that are treated with the combination of dabrafenib and trametinib (combi-DT). Given the expanded indication for combi-DT, management of pyrexia is a high priority. No previous case series has revealed which blood markers reflect the course of pyrexia and there is no consensus on the management strategy for pyrexia.

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Extramammary Paget's disease (EMPD) is a rare cutaneous malignancy that mainly affects the senior population. There is a relatively high risk of postoperative complications from surgery in the senior population, such as disuse syndrome, deep vein thrombosis and postoperative delirium. To prevent such postoperative complications, early ambulation is recommended.

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