Publications by authors named "Koji Arizono"

Article Synopsis
  • The study emphasizes the significance of nickel, copper, and selenium as essential biometals in various industries, but highlights their harmful impact as environmental pollutants when they exceed normal levels, particularly in aquatic ecosystems.
  • Research on medaka fish embryos revealed that exposure to these biometals led to significant developmental abnormalities and increased mortality rates throughout a 14-day observation period.
  • Gene expression analysis showed that copper was the most toxic, affecting over 4,700 genes, while all three biometals caused detrimental effects on fish embryo development, underscoring the necessity of monitoring biometal levels to protect aquatic life.
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  • Artisanal and small-scale gold mining (ASGM) in Sudan poses serious health risks due to high mercury emissions, particularly in the Abu Hamad community.
  • Analysis of soil and water samples showed peak mercury levels near amalgam burning sites, with significant health hazards identified for both adults and children who live close to these areas.
  • The study highlights the critical need for safer mining practices, such as using retorts, to minimize mercury exposure and safeguard the health of ASGM communities.
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Concentrations of fipronil (Fip) and several of its derivatives were detected in samples from four rivers and four estuaries in Japan. LC-MS/MS analysis detected Fip and its derivatives, except for fipronil detrifluoromethylsulfinyl, in almost all samples. The total concentrations of the five compounds were approximately two-fold greater in river water (mean: 21.

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It is well established that platinum-based drugs, including oxaliplatin (L-OHP) and cisplatin (CDDP), as well as microtubule inhibitors paclitaxel (PTX) and vincristine (VCR), are associated with chemotherapy-induced peripheral neuropathy (CIPN). In this study, we examined and compared the characteristics of neuropathies induced by L-OHP, CDDP, PTX, and VCR to evaluate whether Caenorhabditis elegans (C. elegans) could serve as a model organism for human CIPN.

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Equine estrogens (EQs) are steroidal hormones isolated from the urine of pregnant mares and are used in the formulation of human medications. This study initially investigated the embryonic developmental toxicity of equilin (Eq) and equilenin (Eqn) in medaka (Oryzias latipes). Malformations were observed in embryos exposed to nominal concentrations of 1 and 10 mg/L of Eq and Eqn.

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Frequent discharge of mercury waste from artisanal and small-scale gold mining (ASGM) facilities into nearby farms may contaminate foodstuffs and the entire farms. High contamination levels may result in ecological risks to the soil, plants, animals, humans, and the entire farm ecosystem. This original research is the first study within the catchment areas that describes the effects of mercury waste on the entire farm ecosystem.

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Mercury (Hg) is one of the most harmful metals and has been a public health concern according to the World Health Organization (WHO). Artisanal and small-scale gold mining (ASGM) is the world's fastest-growing source of Hg and can release Hg into the atmosphere, hydrosphere, and geosphere. Hg has been widely used in ASGM industries throughout Southeast Asia countries, including Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, and Thailand.

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Neonicotinoid pesticides are a class of insecticides that reportedly have harmful effects on bees and dragonflies, causing a reduction in their numbers. Neonicotinoids act as neuroreceptor modulators, and some studies have reported their association with neurodevelopmental disorders. However, the precise effect of neonicotinoids on the central nervous system has not yet been identified.

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The removal of Hg from solid waste plays a key role in environmental protection. In this study, a fast, simple, and effective method for the removal of Hg by acid extraction, using a combination of vortex agitation and ultrasonic irradiation along with hydrobromic acid (HBr), was established using Hg-containing solid wastes. The optimal durations of vortex agitation and ultrasonic irradiation with 48% v/v of HBr were 5 and 6 min, respectively, and total Hg (T-Hg) extraction was achieved within 21 min.

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Mercury (Hg), cadmium (Cd), and lead (Pb) concentrations in marketed cigarettes from South Korea, Vietnam, Japan, Indonesia, Taiwan, Thailand, the United Kingdom (UK), Belgium, Italy, Finland, and France were investigated. The cigarettes from Vietnam and Thailand had the highest trend of Hg. Meanwhile, Cd was found higher in cigarettes from Thailand, the UK, and Belgium.

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Article Synopsis
  • Urban dust in Hanoi has been contaminated with toxic heavy metals, particularly mercury (Hg), from various sources, significantly worsened by a fire at a CFL factory on August 28, 2019.
  • A study conducted two months later found localized Hg pollution, especially in areas downwind from the factory, with levels higher than other directions, posing a risk to public health.
  • The hazard index indicated that children in the most polluted area were at greater risk of adverse health effects from Hg exposure compared to adults, emphasizing the need for monitoring street dust for health assessments.
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Neonicotinoids (NEOs) are the most important globally available class of chemical insecticides since the introduction of synthetic pyrethroids. The adverse effects of NEOs for early development have been reported via in vivo and epidemiological studies. Therefore, prenatal NEOs exposure is highly concerning.

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This study aimed to (i) develop a sensitive method for simultaneous detection and quantification of imidacloprid (IMI) and seven of its metabolites in tissue specimens, and to (ii) determine the biodistribution of the IMI compounds in tissues of C57BL/6J male mice; after exposure to 0.6 mg/kg bw/day of IMI (10% of no observable adverse effect level of IMI) through a powdered diet for 24 weeks. We successfully developed a method which was accurate (recoveries were ≥ 70% for most compounds), sensitive (LODs ≤ 0.

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Article Synopsis
  • Food consumption is the primary way humans are exposed to mercury (Hg), often leading to health issues due to contamination from artisanal and small-scale gold mining (ASGM) waste affecting nearby crops.
  • A study in four communities near Obuasi, Ghana, assessed the health risks of total mercury (THg) and methylmercury (MeHg) in plantains, revealing that only Odumase surpassed safety levels, posing potential non-carcinogenic health risks for residents.
  • In contrast, other areas like Tweapease, Nyamebekyere, and Ahansonyewodea showed THg levels below recommended limits for both adults and children, indicating a lower risk of chronic health effects from consuming contaminated
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Neonicotinoids, which act as agonists of the nicotinic acetylcholine receptors of insects, are widely used pesticides worldwide. Although epidemiological studies revealed that the detection amounts of neonicotinoids in urine are higher in the elderly population than other age-groups, there is no available information regarding the risks of neonicotinoids to older mammals. This study was aimed to investigate aging-related differences in the behavioral effects of the neonicotinoid pesticide clothianidin (CLO).

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Equine estrogens (EEs) are widely used in hormone replacement therapy pharmaceuticals for postmenopausal women. Previous studies have shown that EEs occur in the aquatic environment; however, the potential estrogenicity and risk of EEs in aquatic organisms, including fish, have yet to be studied in detail. Therefore, we evaluated the estrogenic potential of major EEs, namely equilin (Eq), 17α-dihydroequilin (17α-Eq), 17β-dihydroequilin (17β-Eq), equilenin (Eqn), 17α-dihydroequilenin (17α-Eqn), and 17β-dihydroequilenin (17β-Eqn), on medaka (Oryzias latipes) using in vivo and in silico assays.

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Herein, we quantified the concentrations of cadmium (Cd) and arsenic (As) in 63 milled rice (Oryza sativa L.) cultivated in Japan, Vietnam, and Indonesia. We estimated the daily intake of Cd and As by adults and children consuming this rice by inductively coupled plasma-mass spectrometer (ICP-MS).

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Neonicotinoid insecticides are used for agricultural and non-agricultural purposes worldwide. Pets are directly exposed to neonicotinoids in veterinary products and through environmental contamination. Cytochrome P450 (CYP) is among the most significant xenobiotic metabolizing enzymes that oxidizes several chemicals, including neonicotinoids.

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This study assessed the transcription levels of estrogen-responsive genes, such as vitellogenins (Vtg1 and Vtg2), choriogenins (ChgL, ChgH, and ChgHm), cytochrome P450 aromatase (CYP19a1b), and ER subtypes (ERα, ERβ1, and ERβ2), in 7 days-post-fertilization (dpf) embryos and 9 and 12 dpf larvae of medaka (Oryzias latipes) exposed to estrogenic endocrine-disrupting chemicals (EDCs). The <5 h-post-fertilization embryos were exposed to EDCs such as 17β-estradiol (E2), p-n-nonylphenol (NP), and bisphenol A (BPA). In E2 (0.

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Neonicotinoids (NNs), a widely used class of systemic pesticides, are regarded as exhibiting selective toxicity in insects. However, NNs are suspected of exerting adverse effects on mammals as well, including humans. To date, only adult male animal models have been subjected to general toxicity studies of NNs; fetuses have yet to be considered in this context.

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Article Synopsis
  • The study investigates the effects of the polycyclic aromatic hydrocarbon benzo[a]pyrene (BaP) on early life stages of Japanese medaka fish, focusing on embryonic teratogenicity and developmental toxicity.
  • Using a nanosecond pulsed electric field (nsPEF) technique, researchers effectively incorporated BaP into fish embryos, leading to observable cardiovascular and developmental abnormalities.
  • Transcriptome analysis identified upregulated genes related to cardiovascular problems and neural development, suggesting the possible mechanisms behind BaP's teratogenic and developmental effects.
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We investigated the Baikal seal ( Pusa sibirica) peroxisome proliferator-activated receptor α (bsPPARα) transactivation potencies of polybrominated diphenyl ethers (PBDEs) using an in vitro bsPPARα reporter gene assay. BDE47, BDE99, and BDE153 induced bsPPARα-mediated transcriptional activities in a dose-dependent manner. To compare bsPPARα transactivation potencies of PBDEs, perfluorooctanoic acid (PFOA)-based relative potencies (REPs), a ratio of 50% effective concentration of PFOA to the test chemical, were determined.

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Tea is one of the world's most popular beverages due to health promoting effects. Despite these, there have been concerns about the adverse effects of tea contamination by neonicotinoid insecticides. Only a handful of studies on neonicotinoid insecticides in tea have been carried out and this study was therefore performed to determine the concentrations of seven neonicotinoid insecticides and 20 metabolites in Japanese green tea leaves, and black tea leaves from Sri Lanka; and assess the Maximum Daily Intake (MDI) of neonicotinoid insecticides.

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Total mercury (THg) and methylmercury (MeHg) bioaccumulation was explored in the Bimastus parvus species of earthworm (B. parvus) native to the leachate-contaminated forest soils around a Hg-polluted traditional landfill in Japan. General soil properties and concentrations of THg and MeHg in forest soils and in B.

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The contents and spatial distribution of mercury (Hg), including soil-Hg fractionation and Hg-containing native earthworm Bimastos parvus (B. parvus) species, were investigated in the leachate-contaminated zone of a large traditional landfill, Japan. Soil-Hg was fractionated into 5 categories: F1/water soluble Hg (Hg-w), F2/human stomach acid soluble Hg (Hg-h), F3/organic-chelated (Hg-o), F4/elemental Hg (Hg-e), and F5/mercuric sulfide (Hg-s).

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