Publications by authors named "Yasumitsu Ogra"

BCR::ABL1 oncofusion protein drives Philadelphia-chromosome positive acute lymphoblastic leukemia (Ph+ ALL), making it a critical therapeutic target. Tyrosine kinase inhibitors (TKIs) targeting BCR::ABL1 have revolutionized the treatment of Ph+ ALL patients. However, mutations in the kinase domain of BCR::ABL1 commonly impair the sensitivity to TKIs, resulting in drug resistance and poor prognosis in Ph+ ALL.

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Deciduous teeth are a unique medium that record exposure to various elements over time, as they are formed during fetal and infantile periods. We aimed to evaluate the association between infant feeding methods and changes in the distribution of Barium (Ba) and Strontium (Sr) in deciduous teeth of children. The current analysis included 216 children around 6-7 years of age whose deciduous central incisor teeth were provided between March 2018 and February 2020, as an adjunct study of the Japan Environment and Children's study.

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Antimony ecotoxicity studies are often hindered by the incorrect selection of Sb(III) standards and the application of concentrations that do not reflect real environmental exposure. In this study, we used environmentally relevant concentrations of inorganic Sb in its pentavalent [Sb(V)] and trivalent [Sb(III)] oxidation states, as well as the organic species NMG-Sb(V), which is present in Meglumine Antimoniate, to evaluate the effects of Sb on cell viability in human lung (A549), kidney (HEK293), and liver (HepG2) cell lines. Cell viability was assessed in these cells following treatment with 0.

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The essential trace element selenium (Se) plays a significant role in redox homeostasis, while Se is very reactive and has a potent toxicity. Understanding the molecular machinery that supports Se metabolism is important for the both physiological and pathophysiological context. Incorporated Se is translated/transformed in the liver into selenoprotein P (SeP; encoded by Selenop), an extracellular Se carrier protein that effectively transports Se to the cells via the binding to its receptor apolipoprotein E receptor 2 (ApoER2), which is taken up by cells.

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Selenium (Se) is an essential micronutrient for animals. Various chemical forms of Se exist in nature, each with distinct physiological, nutritional, and toxicological properties. In this study, we aimed to determine whether dimethyldiselenide (DMDSe, a monomethylated Se (MMSe) compound) and dimethylselenide (DMSe, a dimethylated Se compound), known gut bacterial metabolites, could serve as Se sources in rats.

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Arsenite [As(III)] is a toxic substance widely present on Earth, and the development of low-cost and simple microbial-based As(III) sensors has been attracting attention. Recently, we discovered that the protein LuxR, which contains multiple cysteine residues with high affinity for As(III), forms an insoluble structure upon binding to As(III) and exhibits OFF-switching properties as a quorum sensing transcriptional activator. Based on this property, the LuxR sensor operates on a new principle distinct from conventional whole-cell As(III) sensors; however, its sensitivity remains a challenge.

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Nanomedicines, which consist of nanoparticles as active ingredients, have been developed and approved for pharmaceutical use. However, no method has been established to quantify ions and nanoparticles containing the same elements separately. We developed an asymmetric flow field-flow fractionation hyphenated to inductively coupled plasma mass spectrometry (AF4-ICP-MS) to assess elemental impurities from ions and nanoparticles of different sizes.

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The arsenic trioxide (ATO)-based cure of acute promyelocytic leukemia is attributed to PML/RARα oncoprotein degradation through binding of its RBCC domain (i.e., consist of RING, B-box1, B-box2, and Coiled-coil) with arsenic.

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Boron is an essential micronutrient required for plant cell wall integrity, as it is necessary for crosslinking the pectic polysaccharide rhamnogalacturonan II. Reproductive organs require a greater amount of boron for development and growth compared with vegetative organs. However, the mechanism by which plants distribute boron to specific organs is not fully understood.

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Rare earth elements, comprising 17 elements including 15 lanthanides, are essential components in numerous high-tech applications. While physicochemical methods are commonly employed to remove toxic heavy metals (e.g.

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The body mitigates the toxic effects of metals through diverse detoxification mechanisms that are activated depending on the chemical species and the burden of metals in each tissue. In this regard, analytical methods that can obtain information on the chemical form and the abundance of metals are required to elucidate the full range of detoxification mechanisms. Laser ablation (LA) is used to trim a specific microregion from tissue sections and visualize elements in it.

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Due to its toxicity, contamination with arsenic, a Group 1 carcinogen, is a significant environmental and public health issue. The toxicity of arsenic varies with its chemical form. For example, inorganic species like arsenite (AsO) and arsenate (AsO) are generally more toxic than organoarsenic compounds.

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Article Synopsis
  • - The study explores the toxic effects of tellurium (Te), focusing on its methylation process by two enzymes, TPMT and INMT.
  • - Researchers used advanced analytical techniques (LC-ICP-MS and GC-MS) to examine how these enzymes transform various Te compounds.
  • - Findings indicate that TPMT and INMT work together to convert tellurite into safer metabolites, specifically trimethyltelluronium ions, which are eliminated through urine.
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Monoclonal antibody drugs (mAb) are widely used to treat various diseases. Keeping quality of mAbs is crucial to maximize efficacy and minimize adverse effects. To this end, mAb content in the drug product must be precisely quantified.

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γ-Glutamyl-β-cyanoalanylglycine (gEcnAG) is a glutathione analog in which the cysteine moiety in glutathione is replaced with β-cyanoalanine, a known plant cyanide metabolite. Previously, gEcnAG was detected in the liver of rats and chicks exposed to β-cyanoalanine. We reported the detection of gEcnAG in naïve mammalian cells using liquid chromatography coupled with tandem quadrupole time-of-flight mass spectrometry (LC-QTOF-MS).

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Elemental analysis at the single-cell level is an emerging technique in the field of inductively coupled plasma mass spectrometry (ICP-MS). In comparison to the analysis of cell suspensions by fast time-resolved analysis, single-cell sampling by laser ablation (LA) allows the discriminatory analysis of single cells according to their size and morphology. In this study, we evaluated the changes in elemental contents in a single cell through differentiation of rat adrenal pheochromocytoma into neuron-like cells by LA-ICP-MS.

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While research has identified several inhibitors of the main protease (Mpro) of SARS-CoV-2, a significant portion of these compounds exhibit reduced activity in the presence of reducing agents, raising concerns about their effectiveness in vivo. Furthermore, the conventional biosafety level 3 (BSL-3) for cellular assays using viral particles poses a limitation for the widespread evaluation of Mpro inhibitor efficacy in a cell-based assay. Here, we established a BSL-1 compatible cellular assay to evaluate the in vivo potential of Mpro inhibitors.

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Article Synopsis
  • - Ferroptosis is a type of cell death caused by an excess of lipid hydroperoxides, which are linked to iron and can be prevented by the enzyme GPX4 that detoxifies these compounds.
  • - GPX4 relies on a special amino acid called selenocysteine (Sec), which is produced from selenium, and proper delivery of selenium is essential due to its high reactivity and low availability in cells.
  • - Researchers discovered that the protein peroxiredoxin 6 (PRDX6) plays a crucial role in the synthesis of selenoproteins by enhancing selenium transfer within the cell, with loss of PRDX6 leading to decreased GPX4 levels and increased ferroptosis.
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Tellurium (Te) is a chalcogen element like sulfur and selenium. Although it is unclear whether Te is an essential nutrient in organisms, unique Te metabolic pathways have been uncovered. We have previously reported that an unknown Te metabolite (UKTe) was observed in plants exposed to tellurate, a highly toxic Te oxyanion, by liquid chromatography-inductively coupled plasma mass spectrometer (LC-ICP-MS).

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Copper is an essential trace element that participates in many biological processes through its unique redox cycling between cuprous (Cu) and cupric (Cu) oxidation states. To elucidate the biological functions of copper, chemical biology tools that enable selective visualization and detection of copper ions and proteins in copper-rich environments are required. Herein, we describe the design of Cu-responsive reagents based on a conditional protein labeling strategy.

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Objectives: We aimed to analyze the subchronic toxicity and tissue distribution of indium after the intratracheal administration of indium-tin oxide nanoparticles (ITO NPs) to the lungs of rats.

Methods: Male Wistar rats were administered a single intratracheal dose of 10 or 20 mg In/kg body weight (BW) of ITO NPs. The control rats received only an intratracheal dose of distilled water.

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We established a size separation method for silica nanoparticles (SiNPs) measuring 10, 30, 50, 70, and 100 nm in diameter using asymmetric flow field flow fractionation hyphenated with inductively coupled plasma mass spectrometry (AF4-ICP-MS), and evaluated the cytotoxicity of SiNPs in human hepatoma HepG2 cells. Analysis of the mixture sample revealed that nanoparticles of different sizes were eluted at approximately 2-min intervals, with no effect on each elution time or percentage recovery. Compared with larger SiNPs, smaller SiNPs exhibited high cytotoxicity when the volume of SiNPs exposed to the cells was the same.

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