記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：European Heart Journal Open  

Aims: There has been a shortage of human studies to elucidate the association between serum arsenic levels and the prevalence of hypertension. This study multidirectionally investigated associations among arsenic exposure, dietary ingestion, and the risk of hypertension by combined human epidemiological and mouse experimental studies. Methods and results: This study focused on the total arsenic level in fasting serum, a biomarker of arsenic exposure. Associations among ingestion frequencies of 54 diet items of Japanese food separated into six categories, total arsenic level in fasting serum, and the prevalence of hypertension were investigated in 2709 general people in Japan. Logistic regression analysis demonstrated a dose-dependent association between serum arsenic level and hypertension and a positive association between the ingestion of fish meat and hypertension. Further analysis showed that the latter association was fully mediated by increased fasting serum arsenic levels in humans. Similarly, oral exposure to the putative human-equivalent dose of arsenic species mixture with the same ratios in a common fish meat in Japan increased systolic blood pressure and arsenic levels in fasting serum in mice. Conclusion: This interdisciplinary approach suggests that fish-meat ingestion is a potential risk factor for arsenic-mediated hypertension. Because the increased consumption of fish meat is a recent global trend, health risks of the increased ingestion of arsenic via fish meat should be further investigated.

DOI： 10.1093/ehjopen/oead074

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Environmental Management  

Hydrogen sulfide (H2S) is known to have wide ranging toxicities not only as a gas but also as dissolved forms in aquatic environments. The diversity of aquatic organisms can be severely affected by hydrogen sulfide at very low concentrations, indicating the urgent necessity to develop an efficient method for removal of hydrogen sulfide in water. In this study, the removal capacity for hydrogen sulfide of our originally developed hydrotalcite-like compound composed of magnesium and iron (MF-HT) was investigated and its potential application for reduction of toxicity to aquatic organisms was evaluated. The MF-HT experimentally showed a high adsorption capacity of 146.5 mg/g with a fast adsorption equilibrium time of 45 min, both of which are top-class compared with those of other adsorbents previously reported. In fact, removal of hydrogen sulfide (1.2–152.5 mg/L) at an average rate of >97.6% was achieved in groundwater samples (n = 16) by the MF-HT within 60 min. The toxicities of groundwater, indicated by inhibition rate for microalgae (primary producers) and immobilization rate for crustaceans (secondary consumers), were reduced by 96.1% and 82.5% in 2-fold and 4-fold diluted groundwater, respectively, after treatment with the MF-HT for 60 min. These results indicate that MF-HT has an excellent safety record for aquatic organisms. After clarifying the adsorption mechanism, excellent reusability of MF-HT was also confirmed after regeneration using 1 M Na2CO3 solution. Considering the efficacy, speed, safety and cost of MF-HT, it could be a novel promising material for solving the problem of hydrogen sulfide pollution in the hydrosphere.

DOI： 10.1016/j.jenvman.2022.115861

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemosphere  

Simultaneous relocation of a group of pollutant sources in a heavily polluted area is a rare event. Such a relocation has been implemented in Hazaribagh, a tannery built-up area with heavy pollution, in Bangladesh. This provides a valuable opportunity to compare the changes in environmental conditions associated with the relocation of multiple putative sources. Our environmental monitoring for a period of 6 years at the stationary areas centered on Hazaribagh geographically revealed trivalent [Cr(III)], hexavalent [Cr(VI)] chromium, lead, iron, and manganese as tannery-related elements after the legal deadline for tannery relocation. The median Cr(III) level in canal water, into which wastewater from tanneries was directly discharged, after the relocation was 97% lower of that before the relocation, indicating a beneficial effect of the relocation. In contrast, the median Cr(VI) level in water samples just after the relocation and 2 years after the relocation were approximately 5-fold and 30-fold higher, respectively, than those before the relocation. These results indicate not only a harmful effect of the relocation but also the possibility of conversion from Cr(III) to Cr(VI) in nature. Although the health hazard indexes considering all of the tannery-related elements in all of the canal water samples before the relocation exceeded the safety thresholds, the percentages of samples in which the indexes exceeded their safety thresholds after the relocation decreased by 32.5%–45.0%. Treatment with our patented hydrotalcite-like compound consisting of magnesium and iron (MF-HT) resulted in decreases in the health hazard indexes in all of the water samples in which the indexes exceeded their safety thresholds to levels lower than their thresholds. Thus, this study shows the double-edged effects associated with the relocation and a potential solution.

DOI： 10.1016/j.chemosphere.2022.135098

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担当区分：筆頭著者,　最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Scientific Reports  

Most patients with ovarian cancer experience recurrence and develop resistance to platinum-based agents. The diagnosis of platinum resistance based on the platinum-free interval is not always accurate and timely in clinical settings. Herein, we used laser ablation inductively coupled plasma mass spectrometry to visualize the platinum distribution in the ovarian cancer tissues at the time of interval debulking surgery after neoadjuvant chemotherapy in 27patients with advanced high-grade serous ovarian cancer. Two distinct patterns of platinum distribution were observed. Type A (n = 16): platinum accumulation at the adjacent stroma but little in the tumor; type B (n = 11): even distribution of platinum throughout the tumor and adjacent stroma. The type A patients treated post-surgery with platinum-based adjuvant chemotherapy showed significantly shorter periods of recurrence after the last platinum-based chemotherapy session (p = 0.020) and were diagnosed with “platinum-resistant recurrence”. Moreover, type A was significantly correlated with worse prognosis (p = 0.031). Post-surgery treatment with non-platinum-based chemotherapy could be effective for the patients classified as type A. Our findings indicate that the platinum resistance can be predicted prior to recurrence, based on the platinum distribution; this could contribute to the selection of more appropriate adjuvant chemotherapy, which may lead to improves prognoses.

DOI： 10.1038/s41598-022-08503-7

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemosphere  

Water pollution caused by tannery wastewater is an important issue in developing countries. Most studies have focused on inorganic chemicals represented by chromium as a tannery-related main pollutant. This is the first study in which pollution of water by tannery-related organic chemicals was assessed by a combination of qualitative and quantitative analyses. Our quantitative analysis showed that the maximum concentration of total phenolic compounds (phenols), consisting of phenol, bisphenol F, p-cresol and chlorocresol, in canal water in a tannery built-up area in Bangladesh was >67-fold higher than the Environmental, Health and Safety (EHS) guideline value. Mapping of our results indicated tanneries as the sources of phenols pollution. Our original depurative, a hydrotalcite-like compound consisting of magnesium and iron (MF-HT), could adsorb all kinds of phenols and exhibited the highest phenol adsorption ability (115.8 mg/g) among reported hydrotalcite-like compounds. The levels of phenols in canal water samples were reduced to levels below the guideline value by using MF-HT with assistance of a photocatalytic reaction. Moreover, the mean level of chromium (112.2 mg/L) in canal water samples was decreased by 99.7% by using the depurative. Thus, the depurative has the potential for solving the problem of tannery-related water pollution by phenols and chromium.

DOI： 10.1016/j.chemosphere.2021.130959

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Allergy and Clinical Immunology  

DOI： 10.1016/j.jaci.2021.05.025

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Allergy and Clinical Immunology  

Background: Air pollutants are suspected to affect pathological conditions of allergic rhinitis (AR). Objectives: After detecting Pb (375 μg/kg) in Japanese cedar pollen, the effects of intranasal exposure to Pb on symptoms of AR were investigated. Methods: Pollen counts, subjective symptoms, and Pb levels in nasal epithelial lining fluid (ELF) were investigated in 44 patients with Japanese cedar pollinosis and 57 controls from preseason to season. Effects of intranasal exposure to Pb on symptoms were confirmed by using a mouse model of AR. Results: Pb levels in ELF from patients were >40% higher than those in ELF from control subjects during the pollen season but not before the pollen season. Pb level in ELF was positively associated with pollen counts for the latest 4 days before visiting a hospital as well as scores of subjective symptoms. Intranasal exposure to Pb exacerbated symptoms in allergic mice, suggesting Pb as an exacerbation factor. Pb levels in ELF and nasal mucosa in Pb-exposed allergic mice were higher than those in Pb-exposed nonallergic mice, despite intranasally challenging the same amount of Pb. Because the increased Pb level in the nasal mucosa of Pb-exposed allergic mice was decreased after washing the nasal cavity, Pb on the surface of but not inside the nasal mucosa may have been a source of increased Pb level in ELF of allergic mice. Conclusions: Increased nasal Pb level partially derived from pollen could exacerbate subjective symptoms of AR, indicating Pb as a novel hazardous air pollutant for AR.

DOI： 10.1016/j.jaci.2021.03.019

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Aging Cell  

Hair graying is a representative sign of aging in animals and humans. However, the mechanism for hair graying with aging remains largely unknown. In this study, we found that the microscopic appearance of hair follicles without melanocyte stem cells (MSCs) and descendant melanocytes as well as macroscopic appearances of hair graying in RET-transgenic mice carrying RET oncogene (RET-mice) are in accordance with previously reported results for hair graying in humans. Therefore, RET-mice could be a novel model mouse line for age-related hair graying. We further showed hair graying with aging in RET-mice associated with RET-mediated acceleration of hair cycles, increase of senescent follicular keratinocyte stem cells (KSCs), and decreased expression levels of endothelin-1 (ET-1) in bulges, decreased endothelin receptor B (Ednrb) expression in MSCs, resulting in a decreased number of follicular MSCs. We then showed that hair graying in RET-mice was accelerated by congenitally decreased Ednrb expression in MSCs in heterozygously Ednrb-deleted RET-mice [Ednrb(+/−);RET-mice]. We finally partially confirmed common mechanisms of hair graying with aging in mice and humans. Taken together, our results suggest that age-related dysfunction between ET-1 in follicular KSCs and endothelin receptor B (Ednrb) in follicular MSCs via cumulative hair cycles is correlated with hair graying with aging.

DOI： 10.1111/acel.13273

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その他リンク： https://onlinelibrary.wiley.com/doi/full-xml/10.1111/acel.13273

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Environmental Research  

Background: The process for leather material production is carried out in developing countries using a large amount of trivalent chromium [Cr(III)]. Assesment of health risks for millions of workers in tanneries worldwide that are highly polluted with Cr(III) is needed. Methods: Levels of total Cr and its chemical species in wastewater samples from tannery built-up areas of Bangladesh were investigated. Cr-mediated renal damage was assessed in 100 male tannery workers by epidemiological analysis consisting of questionnaires and measurements of levels of urinary Cr and urinary renal damage markers [urinary levels of total protein and kidney injury molecule-1 (KIM-1)]. Results: High levels of total Cr (mean ± standard deviation = 1,908,762 ± 703,450 μg/L) were detected in wastewater samples from 13 sites of tanneries. More than 99.99% of total Cr in the wastewater was Cr(III), indicating that workers in the tanneries were exposed to large concentrations of Cr(III). Cr levels (mean ± standard, 2.89 ± 4.23 μg/g creatinine) in urine samples from the workers in tanneries were >24-fold higher than the levels in a general population previously reported. Multivariate analysis showed significant correlations between urinary levels of Cr and urinary levels of renal damage biomarkers. Nagelkerke Pseudo R2 values also showed that Cr level is the strongest contributor to the levels of renal damage biomarkers in the workers. Conclusion: Our results newly suggest that excess exposure to Cr(III) could be a risk for renal damage in humans.

DOI： 10.1016/j.envres.2020.109770

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemosphere  

Toxic compounds from the mother's diet and medication in addition to genetic factors and infection during pregnancy remain risks for various congenital disorders and misbirth. To ensure the safety of food and drugs for pregnant women, establishment of an in vitro system that morphologically resembles human tissues has been long desired. In this study, we focused on dorsal mesoderm elongation, one of the critical early development events for trunk formation, and we established in vitro autonomous elongating tissues from human induced pluripotent stem cells (hiPSCs). This artificial tissue elongation is regulated by MYOSIN II and FGF signaling, and is diminished by methylmercury or retinoic acid (RA), similar to in vivo human developmental disabilities. Moreover, our method for differentiation of hiPSCs requires only a short culture period, and the elongation is cell number-independent. Therefore, our in vitro human tissue elongation system is a potential tool for risk assessment assays for identification of teratogenic chemicals via human tissue morphogenesis.

DOI： 10.1016/j.chemosphere.2020.126124

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Environmental Health and Preventive Medicine  

Well water could be a stable source of drinking water. Recently, the use of well water as drinking water has been encouraged in developing countries. However, many kinds of disorders caused by toxic elements in well drinking water have been reported. It is our urgent task to resolve the global issue of element-originating diseases. In this review article, our multidisciplinary approaches focusing on oncogenic toxicities and disturbances of sensory organs (skin and ear) induced by arsenic and barium are introduced. First, our environmental monitoring in developing countries in Asia showed elevated concentrations of arsenic and barium in well drinking water. Then our experimental studies in mice and our epidemiological studies in humans showed arsenic-mediated increased risks of hyperpigmented skin and hearing loss with partial elucidation of their mechanisms. Our experimental studies using cultured cells with focus on the expression and activity levels of intracellular signal transduction molecules such as c-SRC, c-RET, and oncogenic RET showed risks for malignant transformation and/or progression arose from arsenic and barium. Finally, our original hydrotalcite-like compound was proposed as a novel remediation system to effectively remove arsenic and barium from well drinking water. Hopefully, comprehensive studies consisting of (1) environmental monitoring, (2) health risk assessments, and (3) remediation will be expanded in the field of environmental health to prevent various disorders caused by environmental factors including toxic elements in drinking water.

DOI： 10.1186/s12199-020-00855-8

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担当区分：筆頭著者,　最終著者,　責任著者   記述言語：日本語   出版者・発行元：日本毒性学会  

<p>【背景】モリブデンは、金属イオン補因子として知られている。特に、Xanthine oxidoreductaseなどの酸化還元酵素の補因子として生体内の酸化還元反応に関与している。一方で、過剰摂取により肝及び神経毒性を示すことから、緻密な代謝制御が必要である。しかし、生体内におけるモリブデン代謝機構、特に貯蔵は明らかではない。本研究では、メラニンによるモリブデンの吸着貯蔵能をin vivo及びin vitroにて明らかにすることを目的とした。</p><p>【方法】野生型及びメラニン高蓄積ヘアレスマウスを用い、皮膚におけるメラニン蓄積を色彩色差計にて評価した。皮膚中モリブデン量はICP-MSにて分析し、メラニンとの相関性を検討した。メラニンとモリブデンの直接的な結合については、無細胞系in vitro吸着試験にて検討した。吸着等温式にて最大吸着能を解析した。</p><p>【結果】皮膚におけるメラニン蓄積量とモリブデン量に正の相関を認めた。in vitro試験より、メラニンとモリブデンの結合がLangmuir型吸着に適合することが明らかとなった。Langmuir吸着等温式より、理論的な最大吸着量は131 µg/mgであった。</p><p>【考察】本研究において、in vivo及びin vitroによる検討から、メラニンがモリブデンと直接結合することが明らかとなった。また、生体内においてメラニンにより貯蔵制御されている可能性が明らかとなった。モリブデンとメラニン間結合の生物学的意義は、未だ十分に明らかではないため、今後の更なる検討が必要である。</p><p>【結論】メラニンがモリブデンの貯蔵制御に関与している可能性が示唆された。</p>

DOI： 10.14869/toxpt.47.1.0_p-206

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担当区分：筆頭著者,　最終著者,　責任著者   記述言語：日本語   出版者・発行元：日本毒性学会  

<p>【目的】低周波騒音（LFN）は100 ヘルツ（Hz）以下の周波数を持つ騒音と定義され、空調・電気機器・重機等から最大110デシベル（dB）の音量で発生している物理的環境因子である。マウスを対象にした我々の過去の研究により、LFNは平衡感覚に影響する事が分かってきているが、リスク評価に基づいたLFNの標的組織の情報が極めて限られており、予防法は確立されていない。本研究は、LFNをマウスに曝露し、平衡感覚の感覚器である内耳の前庭への影響を調べた。</p><p>【方法】野生型マウスを対象に、100 HzのLFNを70-95 dBの音量で1時間曝露した。行動解析と前庭誘発筋電位（cVEMP）により平衡感覚を評価した。免疫組織染色により内耳の前庭の病理解析を実施した。統計解析はSteel-Dwass検定などを用いp＜0.05を有意差ありとした。</p><p>【結果】95 dBのLFNの1時間曝露により平衡感覚の行動解析とcVEMPの成績が有意に低下したが、聴力への影響はなかった。Electron probe microanalysis (EPMA) 解析により、曝露群の前庭の有毛細胞でカルシウムの低下が観察された。免疫組織染色により、前庭の耳石膜のダメージが観察された。最後に、修復分子のHSP70の発現を増強した遺伝子改変マウス（<i>HSP70-Tg</i>）をLFN曝露実験に用いた所、耳石膜ダメージと平衡感覚障害を予防できた。</p><p>【結論】マウスを対象にしたLFN急性曝露の健康リスク評価により、前庭の耳石膜がダメージを受け、前庭の機能障害が誘発される事が分かった。また、その障害はHSP70の発現増強により予防できる可能性が示唆された。</p>

DOI： 10.14869/toxpt.47.1.0_p-151

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemosphere  

Chemical leukoderma is a patchy hypopigmentation in the skin. Phenol derivatives such as raspberry ketone have been reported to cause the development of occupationally induced leukoderma. Recently, 2% (w/w) rhododenol, a reduced form of raspberry ketone used in a skin-lightning agent, also caused the development of leukoderma in >16,000 users, about 2% of all users, in Asian countries including Japan. However, a method for assessing the risk of leukoderma caused by 2% rhododenol has not been established despite the fact that the development of leukoderma caused by 30% rhododenol was previously shown in animal experiments. Establishment of a novel technique for risk assessment of leukoderma in humans caused by external treatment with chemicals is needed to prevent a possible future chemical disaster. This study demonstrated that external treatment with 2% rhododenol and the same concentration of raspberry ketone caused the development of leukoderma in murine tail skin without exception with significant decreases in the amount of melanin and number of melanocytes in the epidermis. Thus, a novel in vivo technique that can assess the risk of leukoderma caused by 2% rhododenol was developed. The unique technique using tail skin has the potential to prevent chemical leukoderma in the future.

DOI： 10.1016/j.chemosphere.2019.06.185

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：European Journal of Dermatology  

DOI： 10.1684/ejd.2019.3621

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemosphere  

Since tannery workers in developing countries are chronically exposed to high levels of chromium (Cr), there are serious concerns about health problems. However, there has been limited study in which Cr levels were measured in tannery workers, who are chronically exposed to Cr. Our preliminary inspection showed that there was hyperpigmented skin in tannery workers. We therefore investigated the correlation between skin pigmentation levels digitally evaluated as L* values by using a reflectance spectrophotometer and Cr levels in skin appendages in 100 male tannery workers and in 49 male non-tannery workers in Bangladesh. Digitalized skin pigmentation levels of the face and feet in addition to Cr levels in hair and toenails in tannery workers were significantly higher than those in non-tannery workers in our univariate analysis. Spearman's rank correlation coefficient analysis showed significant correlation between duration of tannery work (years)and Cr levels in hair (r = 0.62)and toenails (r = 0.61). Our multivariate analysis also showed that Cr levels in hair and toenails were significantly correlated with digitalized skin pigmentation levels of the face and feet in addition to duration of tannery work in all participants. Thus, our results showed the development of hyperpigmented skin in tannery workers. Our results also suggested that hyperpigmented skin could be a useful diagnostic marker for chronic exposure to Cr. Furthermore, cutaneous L* value might be a convenient marker for detection of chronic Cr poisoning, since the digitalized values enable objective evaluation of skin pigmented levels by general people as well as dermatologists.

DOI： 10.1016/j.chemosphere.2019.04.112

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Environmental Health and Preventive Medicine  

Background: Melanin is detectable in various sense organs including the skin in animals. It has been reported that melanin adsorbs toxic elements such as mercury, cadmium, and lead. In this study, we investigated the adsorption of molybdenum, which is widely recognized as a toxic element, by melanin. Methods: Molybdenum level of the mouse skin was measured by inductively coupled plasma mass spectrometry. The pigmentation level of murine skin was digitalized as the Lvalue by using a reflectance spectrophotometer. An in vitro adsorption assay was performed to confirm the interaction between molybdenum and melanin. Results: Our analysis of hairless mice with different levels of skin pigmentation showed that the level of molybdenum increased with an increase in the level of skin pigmentation (Lvalue). Moreover, our analysis by Spearman's correlation coefficient test showed a strong correlation (r =-0.9441, p < 0.0001) between Lvalue and molybdenum level. Our cell-free experiment using the Langmuir isotherm provided evidence for the adsorption of molybdenum by melanin. The maximum adsorption capacity of 1 mg of synthetic melanin for molybdenum was 131 μg in theory. Conclusion: Our in vivo and in vitro results showed a new aspect of melanin as an adsorbent of molybdenum.

DOI： 10.1186/s12199-019-0791-y

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Scientific Reports  

About 80% of young people use personal listening devices (PLDs) including MP3 players to listen to music, which consists of sound components with various frequencies. Previous studies showed that exposure to noise of high intensities affected balance in humans. However, there is no information about a frequency-dependent effect of sound components in music from a PLD on balance in young people. In this study, we determined the associations between sound component levels (dB) at 100, 1000 and 4000 Hz in music from a portable listening device (PLD) and balance objectively determined by posturography in young adults (n = 110). We divided the subjects into two groups (low and high exposure groups) based on cut-off values of sound component levels at each frequency using receiver operating characteristic (ROC) curves. Balance in the high exposure group (≥46.6 dB) at 100 Hz was significantly better than that in low exposure group in logistic regression models adjusted for sex, BMI, smoking status and alcohol intake, while there were no significant associations at 1000 and 4000 Hz. Thus, this study demonstrated for the first time that the sound component at 100 Hz with more than 46.6 dB in music improved balance in young adults.

DOI： 10.1038/s41598-018-35244-3

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemosphere  

At present, beneficial effects of melanin and harmful effects of barium have been reported. However, little is known about the adsorption of barium, and even less is known about the biological significance of adsorption of barium by melanin. In this study, we showed that there was a strong correlation between the digitalized level of skin pigmentation and barium level in murine skin compared to the correlations between skin pigmentation level and levels of homologous elements of barium (magnesium, calcium and strontium). The concentration of subcutaneously injected barium in skin with a high level of pigmentation was higher than that in skin with a low level of pigmentation. Our cell-free experiment using the Langmuir isotherm for adsorption of barium in synthetic melanin also provided direct evidence of adsorption of barium by melanin. We then investigated the biological significance of melanin-mediated barium adsorption. We found barium-mediated increase in transforming activity in pigmented melanocytes (melan-a) but not in unpigmented melanocytes (melan-c) after confirming that the barium level in melan-a melanocytes was 3.4-fold higher than that in melan-c melanocytes after culture of 5 μM barium for 24 h. Taken together, our results not only indicate adsorption of barium by melanin in mice, cells and cell-free systems but also suggest a disadvantageous effect of adsorption of barium by melanin on transforming activity in cultured cells.

DOI： 10.1016/j.chemosphere.2018.07.022

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.ydbio.2017.09.034

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7554/eLife.10230

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.stemcr.2014.09.020

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.stemcr.2014.06.018

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1126/science.1241796

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1038/ncomms2229

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Science of the Total Environment  

Harmful health effects of exposure to low-frequency noise (LFN) defined as noise with frequencies at ≤100 Hz on the circulatory system have been a concern. However, there has been no study on the effects of exposure to LFN on the circulatory system with consideration of its frequencies and decibels. In this study, the effects of short-term exposure to broad-band LFNs and their pure-tone components (pure-tone LFNs) on cutaneous blood flow in the extremities including the hands were investigated. In our fieldwork study, we first sampled some kinds of common broad-band LFNs. Our human study then showed that broad-band LFN with a narrower frequency range more strongly increased cutaneous blood flow than did broad-band LFN with a wider frequency range. Pure-tone LFNs of 70–100 Hz at ≤85 dB(Z), but not pure-tone LFNs exceeding 100 Hz, further increased levels of cutaneous blood flow. Our wavelet-transform spectrum analysis of cutaneous blood flow next revealed that the nitric oxide (NO)-dependent and -independent vascular activities of the vascular endothelium were specifically increased by exposure to pure-tone LFN. Our animal study again indicated that exposure to pure-tone LFN increased cutaneous blood flow in mice with impairments of bilateral inner ears as well as cutaneous blood flow in control mice, suggesting a limited effect of inner ear function on the LFN-mediated increase in cutaneous blood flow. The NO-dependent suppressive effect of pure-tone LFN on cutaneous blood flow was confirmed by inhibition of vascular endothelial activity through intravenous injection of an NO inhibitor in wild-type mice. Taken together, the results of this study demonstrated that the vascular endothelium is a target tissue of LFN and that NO is an effector of the LFN-mediated increase in cutaneous blood flow. Since improvement of peripheral circulation could generally promote human health, short-term exposure to LFN may be beneficial for health.

DOI： 10.1016/j.scitotenv.2022.158828

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemosphere  

Hexavalent chromium [Cr(VI)], which has a strong corrosive effect, has been reported to cause perforation of the eardrum. Trivalent chromium [Cr(III)] also has a weak corrosive effect. However, there has been no study on the effects of exposure to Cr, either Cr(VI) or Cr(III), on hearing levels in animals or humans. In this study, the effect of Cr(III) exposure on hearing levels was determined in a human study. Then the reproducibility of the results obtained in the human study and the etiology were investigated in an animal study. The mean levels of total chromium (t-Cr) in hair and toenails from 100 Bangladeshi tannery workers were >20-fold and >360-fold higher, respectively, than those in hair and toenails from 49 Bangladeshi non-tannery workers (office workers). Multivariate analysis revealed decreases of hearing levels (DHLs) at 1 k and 4 k Hz, frequencies that are crucial for understanding language, but not at 8 k and 12 k Hz, in the tannery workers. Since >99.99% of t-Cr in the wastewater that the workers were in direct contact with in the tanneries was Cr(III), the epidemiological results suggest Cr(III)-mediated DHLs in the tannery workers. The results of animal experiments in this study further showed that treatment with eardrops but not intraperitoneal injection with the same amount of Cr(III) that tannery workers might be exposed to resulted in DHL with a damaged eardrum in mice. Previous studies suggested that Cr(III) can directly reach the eardrums of tannery workers via droplets in the air. Cr(III) could also reach the eardrum via picking an ear canal with a finger contaminated with tannery wastewater including Cr(III). Taken together, the results of both human and animal studies suggest the risk of DHLs caused by damage of the eardrum through external exposure to Cr(III) via the ear canal.

DOI： 10.1016/j.chemosphere.2022.135571

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.3389/fcell.2020.622308

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.ydbio.2017.10.008

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.devcel.2017.03.002

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.ydbio.2016.12.023

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1038/srep11428

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.stem.2013.11.007

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.ydbio.2012.10.019

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1371/journal.pone.0061352

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1073/pnas.1116738109

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2108/zsj.28.809

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.ydbio.2010.11.021

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/dvdy.22451

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1111/j.1440-169X.2009.01164.x

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.mod.2008.10.002

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1042/BC20070091

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1111/j.1440-169X.2007.00981.x

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.mod.2006.07.006

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1111/j.1440-169X.2005.00826.x

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PubMed

記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/dvdy.20472

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PubMed

担当区分：筆頭著者,　最終著者,　責任著者  

DOI： 10.1111/j.1440-169x.2004.00727.x

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1093/carcin/bgg060

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PubMed

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s00427-002-0253-0

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PubMed

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ACADEMIC PRESS INC  

In order to investigate the neural connection. of planarian, it is imperative to produce an antibody that specifically stains axons. To identify axon-specific genes, we constructed a cDNA library from a single eye by using a single cell PCR method, in which visual neurons are major components, and sequenced one thousand independent clones. We succeeded in the identification of a planarian homologue of synaptotagmin, Djsyt, whose specific expression in neurons was confirmed by in situ hybridization. The antibody against DjSYT specifically stained axons although its mRNA is distributed in the cell bodies. By using anti-DjSYT, we succeeded in the visualization of neural connections in planarians by whole mount staining. The anti-DjSYT antibody will become a powerful tool to analyze the molecular mechanisms underlying neural network formation in planarian. (C) 1999 Academic Press.

DOI： 10.1006/bbrc.1999.0933

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：ZOOLOGICAL SOC JAPAN  

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：ELSEVIER SCIENCE BV  

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：ELSEVIER SCIENCE BV  

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記述言語：英語   出版者・発行元：OXFORD UNIV PRESS  

DOI： 10.1093/carcin/bgg126

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