Search

In this study, the phytoremediation potential of tropical and subtropical arsenic (As) hyperaccumulating fern Pteris vittata in an As contaminated farmland field near an abandoned goldmine was investigated. The tested field is located in a subarctic area of northeast Japan. This study was aimed at decreasing the risk of As in the soil (water-soluble As) with nurturing the soil and respecting the plant life cycle for the sustainable phytoremediation for 8 years. The field was tilled and planted with new seedlings of the fern every spring and the grown fern was harvested every autumn. The biomass and As concentration in fronds, rhizomes and roots of the fern were analyzed separately after harvesting each year. The biomass of the fronds of P. vittata was significantly affected by the yearly change of the weather condition, but As concentration in fronds was kept at 100-150 mg/kg dry weight. The accumulated As in P. vittata was higher than that of As-hyperaccumulator fern Pteris cretica, the native fern in the field trial area. Harvested biomass of P. vittata per plant was also higher than that of P. cretica. More than 43.5 g As/154 m 2 (convertible to 2.82 kg of As per hectare) was removed from the farmland field by P. vittata phytoremediation at the end of the 8-year experiment. Because of the short-term plant growth period and soil tilling process, total As in soil did not show significant depletion. However, the water-soluble As in the surface and deeper soil, which is phytoavailable and easily taken in cultivated plants, decreased to 10 μg/L (Japan Environmental Quality Standard for water-soluble As in soil) by the 8-year phytoremediation using P. vittata. These research data elucidate that the tropical and subtropical As hyperaccumulating fern, P. vittata, is applicable for As phytoremediation in the subarctic climate area., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Aims: We aimed to investigate the association between general mental health and attitudes toward suicide of participants in suicide-prevention gatekeeper training programs., Methods: We conducted a number of half day training seminars within a suicide prevention program addressing gatekeepers. Participants filled in two questionnaires, one measuring general health (General Health Questionnaire, GHQ-12), and one measuring attitudes towards suicide (ATTS)., Results: The total sample size of participants was 230, of whom 115 completed questionnaires. There were no significant differences in demographic backgrounds between the good mental health (GHQ-12 ≤ 4) and the poor mental health (GHQ-12 ≥ 5) groups. The poor mental health group was more likely to think that people have the right to commit suicide., Conclusion: There was a difference in attitudes toward suicide between the good mental health and the poor mental health groups, indicating that attention should be paid to participants' mental health when conducting suicide-prevention gatekeeper training., Competing Interests: Declaration of Competing Interest None., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Transformation of metallic mercury (Hg°) to mercuric ion (Hg 2+ ) in hydrosphere is the entrance of mercury cycle in water environments and leads to toxicological impact of serious global concern. Two yeast strains of Yarrowia (Idd1 and Idd2) isolated from Hg-contaminated sediments were studied for their mediating role in Hg° dissolution and oxidation. Growth of the Yarrowia cells in Hg-free liquid medium, incubated for 5 d in closed air-tight systems containing Hg°, produced extracellular polymeric substances (EPS). Approximately 230 (±5.7) ng and 120 (±6.8) ng of the dissolved Hg° were oxidized to Hg 2+ by the cultures of Idd1 and Idd2, respectively, 5 day post-inoculation. Transmission electron microscopy (TEM) and X-ray energy dispersive spectrophotometry (XEDS) analysis of the EPS and cell mass revealed the presence of extracellular Hg nanoparticles, presumably HgS, as an indication of EPS-Hg complexation that is useful for Hg° dissolution and its eventual oxidation to Hg 2+ by the cells. Fourier transmission infra-red (FTIR) analyses of the EPS and cell-mass during Hg-oxidation revealed that amine and carbonyl groups were used by EPS for Hg complexation. Our findings provided information about mediatory role played by Yarrowia (Idd1 and Idd2) in hydrosphere in biogeochemical cycling of Hg., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: Various surgical techniques have been proposed to treat small aortic annulus. We have used small-diameter mechanical valves for small aortic annulus. The present study examined aortic valve replacement with small diameter mechanical valves to determine their effectiveness., Methods: The study included 67 patients who underwent elective, isolated aortic valve replacement with ATS-Advanced Performance (AP) valves (ATS Medical, Inc, Minneapolis, MN) within our department. The patients were divided into two groups; patients receiving the 16-mm AP valve (16-mm group) and those receiving valves 18-mm AP or larger (>16-mm group)., Results: The mean age of the 16-mm group was significantly higher than that of the >16-mm group. Body surface area was significantly smaller in the 16-mm group than the >16-mm group. We found no significant differences in preoperative conditions between the groups. The effective orifice area index of the mechanical valve was lower in the 16-mm group (0.87+/-0.06 vs 1.12+/-0.13 cm2/m2, p<0.0001). Six patients (40%) in the 16-mm group fell into the category of prosthesis-patient mismatch cases. Although the postoperative pressure gradient was higher in the 16-mm group (33.7+/-12.5 vs 23.16+/-8.78, p<0.01), left ventricular mass index and left ventricular ejection fraction at early and at late follow-up improved from the preoperative period in both groups. We found no significant differences in incidence of postoperative complications, including death., Conclusions: We believe aortic valve replacement with small-diameter mechanical valves (the ATS-AP valves) in patients with a small annulus provides satisfactory remote prognosis. The use of mechanical valves in elderly patients is considered acceptable with strict clinical monitoring to prevent thromboembolism and anticoagulation therapy-induced complications., (Copyright (c) 2010 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

A specific mercuric ion binding protein (MerP) originating from transposon TnMERI1 of Bacillus megaterium strain MB1 isolated from Minamata Bay displayed good adsorption capability for a variety of heavy metals. In this study, the Gram-positive MerP protein was expressed in transgenic Arabidopsis to create a model system for phytoremediation of heavy metals. Under control of an actin promoter, the transgenic Arabidpsis showed higher tolerance and accumulation capacity for mercury, cadium and lead when compared with the control plant. Results from confocal microscopy analysis also indicate that MerP was localized at the cell membrane and vesicles of plant cells. The developed transgenic plants possessing excellent metal-accumulative ability could have potential applications in decontamination of heavy metals.

A new clinical syndrome with prominent cerebellar symptoms in patients living in Kamisu City, Ibaraki Prefecture, Japan, is described. Since the patients ingested drinking water containing diphenylarsinic acid (DPA), a stable degradation product of both diphenylcyanoarsine and diphenylchloroarsine, which were developed for use as chemical weapons and cause severe vomiting and sneezing, DPA was suspected of being responsible for the clinical syndrome. The purpose of the present study was to elucidate prominent cerebellar symptoms due to DPA. The aim of the study was to determine if single (15 mg/kg) or continuous (5 mg/kg/day for 5 weeks) oral administration of DPA to ICR-strain mice induced oxidative and/or nitrosative stress in their brain. Significantly positive staining with malondialdehyde (MDA) and 3-nitrotyrosine (3-NT) was observed in the cerebellar Purkinje cells by repeated administration (5 mg/kg/day) with DPA for 5 weeks that led to the cerebellar symptoms from a behavioral pharmacology standpoint and by single administration of DPA (15 mg/kg). Furthermore, it is possible that the production of 3-NT was not caused by peroxynitrite formation. The present results suggest the possibility that arsenic-associated novel active species may be a factor underlying the oxidative and nitrosative stress in Purkinje cells due to exposure to DPA, and that the damage may lead to the cerebellar symptoms.

Background: Previous studies have demonstrated that atheroembolism during percutaneous coronary intervention is associated with myocardial damage. The purpose of this study is to investigate the clinical and angiographic characteristics related to removable plaque elements in patients undergoing thrombectomy for myocardial infarction., Methods: Eighty consecutive lesions in 80 patients (M/F=58/22, age 65.5+/-11.6 years) with myocardial infarction who underwent thrombectomy (TVAC system, Nipro, Osaka, Japan) prior to mechanical dilatation (balloon angioplasty and/or stent implantation) were investigated. Visible debris was collected and plaque elements (cholesterol clefts and/or foamy cells) were investigated pathologically. Baseline angiographic characteristics [baseline thrombolysis in myocardial infarction (TIMI) grade, culprit lesion, haziness, lesion length, ostium, bifurcation, calcification, eccentricity, thrombus, and multivessel] were analyzed, and predictive angiographic and clinical factors for plaque elements were investigated., Results: There were no complications related to thrombectomy. Final TIMI grade 3 and blush grade 2 or 3 were achieved in 75 (94%) and 66 (83%) patients, respectively. Visible debris specimens were obtained in 49 (61%) patients. Histological plaque elements (cholesterol clefts and/or foamy cells) were observed in 27 out of 49 patients with debris specimens. There was no significant difference in the clinical characteristics between the groups of patients with (group P) and without (group NP) plaque elements. Aspirated plaque elements were more frequently observed in discrete and eccentric lesions (group P vs. group NP: discreteness, 52% vs. 28%, P<.05; eccentricity, 67% vs. 36%, P<.05)., Conclusions: This study demonstrated the clinical characteristics associated with removable plaque components in patients with myocardial infarction undergoing thrombectomy by means of the TVAC system. Discreteness and eccentricity were more frequently observed in lesions with removable plaque elements.

An analytical method using a combination of solid-phase extraction (SPE) and gas chromatography with a flame thermionic detector (GC/FTD) was developed for determination of N-methyl-2-pyrrolidone (NMP), N-methylsuccinimide (MSI), and 2-hydroxy-N-methylsuccinimide (2-HMSI) in human urine. The SPE cartridge of poly(divinylbenzene/hydroxymethacrylate) used was directly loaded with urine sample, followed by elution with methyl isobutyl ketone (MIBK) and subsequent centrifugation, and the supernatant was injected into the capillary GC using a DB1701. This method allowed efficient separation of NMP, MSI, and 2-HMSI, which were nearly free of interference by other GC peaks arising from urine. Recoveries of NMP, MSI, and 2-HMSI from the SPE cartridge were about 98, 101, and 67%, respectively, with limits of detection of 0.04, 0.02, and 0.06 mg/L, respectively, which met the regulatory requirements. The present method was used for assay in biological monitoring of workers exposed to NMP in their occupational environment.

A method for the determination of trivalent arsenicals in urine was examined. Trivalent arsenicals, extracted as complexes with diethylammonium diethyldithiocarbamate (DDDC) into carbon tetrachloride, were determined by liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS). The trivalent methylated arsenicals monomethylarsonous acid (MMA(III)), dimethylarsinous acid (DMA(III)), and trimethylarsine (TMA) were detected in urine of rats that had received dimethylarsinic acid (DMA(V)) or monomethylarsonic acid (MMA(V)) at concentration of 200 microg ml(-1) in drinking water for 24 weeks. This method is the first to permit quantification of trivalent methylated arsenicals in urine without significant changes in concentration during storage or pretreatment.

We investigated the cytogenetic effects of dimethylarsinic acid (DMA), which is the major metabolite of inorganic arsenic compounds, on mouse bone marrow cells after a single intraperitoneal injection to mice. DMA increased mitotic indices significantly at 16, 24 and 48 h after injection, and prolonged the average generation time 1.5 h at the 24 h. These results suggest that DMA may cause mitotic arrest in vivo as well as in vitro. However the activity of mitotic arrest induced by DMA was much weaker than that induced by colchicine. Metaphase cells obtained after administration of DMA without colchicine pretreatment were morphologically normal except for chromosome number, which varied by stage from the prophase to the telophase in M phase as seen after administration of saline. DMA significantly induced aneuploids. The frequencies of euploids with DMA and saline treatment were 55.1 and 94.0%, respectively, and in DMA treatment hyperploids with 1 or 2 extra chromosomes were over 80% of all aneuploids. These results suggest that aneuploidy induced by DMA might be associated with carcinogenicity of arsenic.

The modifying effects of dimethylarsinic acid (DMA), the major metabolite of ingested arsenicals in most mammals, on chemical carcinogenesis were investigated using rat in vivo models and reviewed here. In a multi-organ bioassay, rats pretreated with 5 carcinogens were administered DMA at various concentrations in their drinking water. Significantly increased tumor induction due to DMA was observed in the urinary bladder, kidney, liver, and thyroid gland. This was associated with significantly elevated ornithine decarboxylase activity in the kidneys of DMA-treated animals. To estimate the hazard levels of its promoting influence, further examinations were carried out concerned with urinary bladder and liver carcinogenesis. Doses of 25 and 50 ppm, respectively, of DMA were found capable of enhancing lesion development in the two organs. In conclusion, our data indicate that DMA is a carcinogen or promoter in the urinary bladder, liver, kidney and thyroid gland, in line with previous epidemiological findings.

The nephrotoxicity of dimethylarsinic acid (cacodylic acid, DMA) was examined in male and female F344/DuCrj rats. DMA administered perorally at doses of 113, 85, and 57 mg/kg for 4 weeks produced dose-related decreases in body weight and survival rate in both sexes. Mortality was higher and appeared more quickly in females than in males. Histopathological findings in the kidney were proximal tubular degeneration and necrosis, as well as papillary necrosis, and hyperplasia of the epithelium covering the papillae. Since extensive proximal tubular necrosis was observed only in dead animals of both sexes, and not in survivors or the controls, it was therefore concluded that the main cause of death could be attributed to nephrotoxicity of DMA. The results thus show that DMA is nephrotoxic to both male and female rats.

The genotoxicity of beryllium, gallium and antimony compounds was studied with the rec, Salmonella mutagenicity and SCE assays. In the rec assay, all the salts of the metals, BeCl2, Be(NO3)2, GaCl3, Ga(NO3)3, SbCl3, SbCl5, and an oxide, Sb2O3, had DNA-damaging activity. None of the compounds was mutagenic to Salmonella. In the SCE assays using V79 cells, 2 antimony(III) compounds, SbCl3 and Sb2O3, and 2 beryllium compounds, BeCl2 and Be(NO3)2, induced SCEs significantly. Sb2O3, slightly soluble in water, was positive in both the rec assay and the SCE assay at very low doses.