Lead and Arsenic in Shed Deciduous Teeth of Children Living Near a Lead-Acid Battery Smelter.
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ABSTRACT:
SUBMITTER: Johnston JE
PROVIDER: S-EPMC6996839 | biostudies-literature | 2019 May
REPOSITORIES: biostudies-literature
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Project description:To isolate high-quality human postnatal stem cells from accessible resources is an important goal for stem-cell research. In this study we found that exfoliated human deciduous tooth contains multipotent stem cells [stem cells from human exfoliated deciduous teeth (SHED)]. SHED were identified to be a population of highly proliferative, clonogenic cells capable of differentiating into a variety of cell types including neural cells, adipocytes, and odontoblasts. After in vivo transplantation, SHED were found to be able to induce bone formation, generate dentin, and survive in mouse brain along with expression of neural markers. Here we show that a naturally exfoliated human organ contains a population of stem cells that are completely different from previously identified stem cells. SHED are not only derived from a very accessible tissue resource but are also capable of providing enough cells for potential clinical application. Thus, exfoliated teeth may be an unexpected unique resource for stem-cell therapies including autologous stem-cell transplantation and tissue engineering.
| S-EPMC156282 | biostudies-literature
Project description:Atmospheric deposition samples were collected over 15 mo at several locations near an operating smelter and an abandoned Pb smelter to investigate the contribution of Pb smelting to depositional fluxes and potential local air quality degradation. Samples were analyzed for As, Cd, Cu, Pb, and Zn and subjected to scanning electron microscopy (SEM)-energy dispersive spectroscopy (EDS). Concentrations of Cd and Pb at both sites were greater than at the control site (p < .05), and significant correlations existed between Cd and Pb concentrations at both sites (p < .05). Monthly depositional flux variations at both sites were similar, with greater deposition during cold and dry periods. Heavy metal(loid)s deposition during these periods was correlated with wind speed. Greater Cd depositional flux differences were found between the smelter and control sites compared with other elements. The SEM images suggested that some particles at the operating smelter site were from Pb smelting material. However, most particles at both sites had no characteristics of smelting, suggesting reactions occurred between the smelter-emitted particles and soil components. The EDS results indicated that atmospheric deposition from both sites had lower Pb concentrations than smelting material or ash. The main atmospheric deposition source at the operating and abandoned sites was likely from the resuspension of heavy metal(loid)-enriched soil particles. Greater risk of air pollution from historical Pb smelting facilities exists years after closing down. Reducing soil wind erosional losses may help reduce heavy metal(loid)s dispersion across environments.
| S-EPMC7963641 | biostudies-literature
Project description:Background:Lead can cause significant biological and neurologic damage, even at small concentrations, and young children are at higher risk. Informal recycling of lead batteries and lead-based workshops/industries have increased the burden of lead toxicity in developing countries, including India. Many informal recycling lead battery workshops have been established by the local people of Patna, Bihar as self-employment opportunities. However, most of the residents are not aware of the risk factors associated with lead poisoning. Objectives:The present pilot study aimed to assess blood lead levels (BLLs) and hemoglobin levels among children aged between 3 to 12 years in the settlement of Karmalichak near Patna, India. Materials and Methods:Children residing near the informal lead battery manufacturing unit were selected for BLL assessment. A total of 41 children were enrolled in the questionnairebased survey. Results:All the children in the present study had detectable lead concentrations in their blood. Only 9% of the studied children had a BLL ?5 ?g/dl, while 91% children had a BLL above >5 ?g/dl. Conclusions:The present study carried out in children of Karmalichak region of Patna, India was an attempt to better understand the problem of lead toxicity, describe the epidemiology of its adverse effects, identify sources and routes of exposure, illustrate the clinical effects and develop strategies of prevention so that remedial measures may be taken by government agencies and regulatory bodies. In view of the high lead levels in children in the study area, attempts are being made to develop strategies for future prevention by relocating the informal battery recycling workshops from the area. Moreover, parents have been advised to increase nutritional supplementation of children by providing calcium-, iron- and zinc-rich foods, including milk and vegetables. Participant Consent:Obtained. Ethical Approval:The study was approved by the ethical committee of Era's Lucknow Medical College & Hospital, Era University, Lucknow (India). Competing Interests:The authors declare no competing financial interests.
| S-EPMC7058140 | biostudies-literature
Project description:Human dental tissues are sources of neural crest origin multipotent stem cells whose regenerative potential is a focus of extensive studies. Rational programming of clinical applications requires a more detailed knowledge of the characters inherited from neural crest. Investigation of neural crest cells generated from human pluripotent stem cells provided opportunity for their comparison with the postnatal dental cells. The purpose of this study was to investigate the role of the culture conditions in the expression by dental cells of neural crest characters. The results of the study demonstrate that specific neural crest cells requirements, serum-free, active WNT signaling and inactive SMAD 2/3, are needed for the activity of the neural crest characters in dental cells. Specifically, the decreasing concentration of fetal bovine serum (FBS) from regularly used for dental cells 10% to 2% and below, or using serum-free medium, led to emergence of a subset of epithelial-like cells expressing the two key neural crest markers, p75 and HNK-1. Further, the serum-free medium supplemented with neural crest signaling requirements (WNT inducer BIO and TGF-β inhibitor REPSOX), induced epithelial-like phenotype, upregulated the p75, Sox10 and E-Cadherin and downregulated the mesenchymal genes (SNAIL1, ZEB1, TWIST). An expansion medium containing 2% FBS allowed to obtain an epithelial/mesenchymal SHED population showing high proliferation, clonogenic, multi-lineage differentiation capacities. Future experiments will be required to determine the effects of these features on regenerative potential of this novel SHED population.
| S-EPMC5268458 | biostudies-literature
Project description:Few studies have measured the effect of short-term exposure to industrial emissions on the respiratory health of children. Here we estimate the risk of hospitalization for asthma and bronchiolitis in young children associated with their recent exposure to emissions from an aluminum smelter. We used a case-crossover design to assess the risk of hospitalization, February 1999-December 2008, in relation to short-term variation in levels of exposure among children 0-4 years old living less than 7.5 km from the smelter. The percentage of hours per day that the residence of a hospitalized child was in the shadow of winds crossing the smelter was used to estimate the effect of wind-borne emissions on case and crossover days. Community-wide pollutant exposure was estimated through daily mean and daily maximum SO2 and PM2.5 concentrations measured at a fixed monitoring site near the smelter. Odds ratios (OR) were estimated using conditional logistic regressions. The risk of same-day hospitalization for asthma or bronchiolitis increased with the percentage of hours in a day that a child's residence was downwind of the smelter. For children aged 2-4 years, the OR was 1.27 (95% CI=1.03-1.56; n=103 hospitalizations), for an interquartile range (IQR) of 21% of hours being downwind. In this age group, the OR with PM2.5 daily mean levels was slightly smaller than with the hours downwind (OR: 1.22 for an IQR of 15.7 μg/m(3), 95% CI=1.03-1.44; n=94 hospitalizations). Trends were observed between hospitalizations and levels of SO2 for children 2-4 years old. Increasing short-term exposure to emissions from a Quebec aluminum smelter was associated with an increased risk of hospitalization for asthma and bronchiolitis in young children who live nearby. Estimating exposure through records of wind direction allows for the integration of exposure to all pollutants carried from the smelter stack.
| S-EPMC3748758 | biostudies-other
Project description:BackgroundLead, a potent neurotoxin, causes irreversible damage to the nervous system, and low- and middle-income countries face huge health and economic productivity losses due to childhood lead exposure. In Bangladesh, informal Used Lead Acid Battery (ULAB) recycling sites are an important source of lead pollution. Little is known about lead awareness among communities exposed to ULAB recycling. Therefore, this study aims to assess knowledge, attitudes, and practices related to lead pollution among caregivers of young children and adolescents living adjacent to informal ULAB sites.MethodsA cross-sectional study was conducted among 732 mothers of young children and adolescents in 4 districts of Bangladesh (survey and observation). Simple and multiple linear regression was conducted to describe patterns and predictors of lead-related knowledge and practices.Results60% of respondents had heard the name 'lead' ("shisha"). The mean knowledge score was low (19 out of 44). Residents of high-risk districts, male respondents, and those with more than 5 years of schooling were significantly more likely to have higher knowledge scores than others. In terms of attitude, 52% of respondents perceived lead to be risky for human health but 43% thought lead pollution was controllable. Observation of households for lead exposure revealed that 63% of children and adolescents play or pass by ULAB sites, 29% ate non-food items, 41% of households had visible paint chips on the walls, 59% households used polished turmeric and 15% used lead-soldered cans to store foods. Among protective practices, 70% reported cleaning floors, 84% consumed iron-rich foods, and 48% consumed calcium-rich foods.ConclusionsThe population had a high potential for lead exposure. Their knowledge about lead was limited, and risk perception was moderate. To reduce lead exposure and increase knowledge and awareness among the at-risk population, it is crucial to take measures such as mass awareness campaigns through media and schools. It is important to strengthen the implementation of existing policies, such as policies on leaded gasoline, paints, and lead-acid batteries, that can address the sources of lead exposure for the community.
| S-EPMC11299337 | biostudies-literature
Project description:ObjectivesThe present study was designed to investigate the microbial profiles of teeth in different locations in mixed-dentition-stage children, and to compare the microbiomes of permanent and deciduous teeth in the same healthy oral cavity.MethodsSupragingival plaque samples of teeth in various locations-the first permanent molars, deciduous molars, deciduous canines and incisors and permanent incisors-were collected from 20 healthy mixed-dentition-stage children with 10-12 permanent teeth erupted. Plaque DNA was extracted, and the V3-V4 hypervariable region of the bacterial 16S rRNA gene was amplified and subjected to sequencing.ResultsOn average, 18,051 high-quality sequences per sample were generated. Permanent tooth sites tended to host more diverse bacterial communities than those of deciduous tooth sites. A total of 12 phyla, 21 classes, 38 orders, 66 families, 74 genera were detected ultimately. Five predominant phyla (Proteobacteria, Firmicutes, Bacteroidetes, Fusobacteria and Actinobacteria) were highly variable among sites. Of 26 genera with a mean relative abundance of >0.1%, 16 showed significant differences in relative abundance among the groups. More than 20% of the total operational taxonomical units were detected only in permanent or deciduous teeth. The variation in the microbial community composition was due mainly to permanent teeth being enriched in Actinomyces and deciduous teeth in Treponema. The core microbiome of supragingival plaque in mixed dentition comprised 19 genera with complex correlationships.ConclusionOur results suggest differences in microbial diversity and composition between permanent and deciduous teeth sites in mixed dentition. Moreover, the core microbiome of these sites was determined. These findings enhance our understanding of the development of the native oral microbiota with age.
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Project description:Ethylenediaminetetraacetic acid (EDTA) has been widely used as an effective reagent for removal of lead from soil because of its high lead extraction efficiency caused by the high thermodynamic stability of the Pb(ii)-EDTA complex. In this study, EDTA was used as a lixiviant for recovery of lead from residues (matte and slag) of secondary lead smelter plants. The residues were composed mainly of iron (34-66 wt%) and lead (7-11 wt%). Leaching parameters (EDTA concentration, pH, temperature, liquid-to-solid ratio and leaching time) were optimized. The optimum leaching efficiency was achieved when leached for 1 h at room temperature using 0.05 mol L-1 EDTA at a liquid-to-solid ratio of 5 mL g-1. At such conditions, 72 to 80% of lead and less than 1% of iron were leached from both matte and slag. The high selectivity towards lead with minimal co-dissolution of iron is a major advantage since it reduces the chemical consumption and simplifies the downstream processes. Although the stability constants of the complexes Fe(iii)-EDTA, Fe(ii)-EDTA and Pb-EDTA are all large (log K S 25.1, 14.33 and 18.04, respectively), the leaching of iron was most likely limited by its presence in insoluble phases such as iron oxides, sulfides and silicates in the residues. 100% leaching of lead was achieved by a multi-step leaching process where the leaching residues were contacted three times by a fresh EDTA solution. To recover EDTA, first iron was precipitated as iron hydroxide by raising the pH of pregnant leach solution (PLS) above 12.6 using sodium hydroxide, followed by precipitation of lead as lead sulfide by adding ammonium sulfide. The recovered EDTA was successfully reused two times for leaching without significant changes in leaching yields.
| S-EPMC9057912 | biostudies-literature
Project description:Arsenic toxicity is a global health problem affecting millions of people. Contamination is caused by arsenic from natural geological sources leaching into aquifers, contaminating drinking water, and may also be caused by mining and other industrial processes. Acute arsenic poisoning is associated with nausea, vomiting, abdominal pain, and severe diarrhea. Chronic arsenic toxicity results in multisystemic diseases leading to central nervous system (CNS) impairments such as cognitive or intellectual deficits in children. Over the past ten years, arsenic contamination has been reported in northern Thailand. The Ministry of Public Health; Thailand, Forensic Science Institute Thammasat University, and the Research Center to Promote Safety and Prevent Injuries in Children at the Ramathibodi Hospital compiled a report on the health impact of the population within a 10 kilometer radius around a mine tailing in the Phichit, Phitsanulok, and Phetchabun Provinces of Thailand. It showed that more than 30 % of children (aged 8-13 years) had higher than normal arsenic contamination levels based on the Agency for Toxic Substances and Disease Registry (ATSDR). After the publication of that report, the mine was temporarily closed in 2016. Based on this data, this research aimed to follow arsenic contamination after the mining operation had stopped operation for three years. The study showed that 4.5 % of school aged children had levels of inorganic arsenic in their urine, higher than the normal range (ATSDR), showing clearly that inorganic arsenic contamination is still above the normal range in children living near an inactive mining site. Therefore, monitoring heavy metal contamination in Thailand and the health effects on vulnerable children who live near mines during regular operation or after being temporarily suspended can prevent and mitigate possible health impacts.
| S-EPMC9441675 | biostudies-literature
Project description:In this study, smelter contaminated soil was treated with various soil amendments (ferric sulfate [Fe2(SO4)3], triple superphosphate [TSP] and biochar) to determine their efficacy in immobilizing soil lead (Pb) and arsenic (As). In soils incubated with ferric sulfate (0.6M), gastric phase Pb bioaccessibility was reduced from 1939 ± 17 mg kg-1 to 245 ± 4.7 mg kg-1, while intestinal phase bioaccessibility was reduced from 194 ± 25 mg kg-1 to 11.9 ± 3.5 mg kg-1, driven by the formation of plumbojarosite. In TSP treated soils, there were minor reductions in gastric phase Pb bioaccessibility (to 1631 ± 14 mg kg-1) at the highest TSP concentration (6000 mg kg-1) although greater reductions were observed in the intestinal phase, with bioaccessibility reduced to 9.3 ± 2.2 mg kg-1. Speciation analysis showed that this was primarily driven by the formation of chloropyromorphite in the intestinal phase following Pb and phosphate solubilization in the low pH gastric fluid. At the highest concentration (10% w/w), biochar treated soils showed negligible decreases in Pb bioaccessibility in both gastric and intestinal phases. Validation of bioaccessibility outcomes using an in vivo mouse assay led to similar results, with treatment effect ratios (TER) of 0.20 ± 0.01, 0.76 ± 0.11 and 1.03 ± 0.10 for ferric sulfate (0.6M), TSP (6000 mg kg-1) and biochar (10% w/w) treatments. Results of in vitro and in vivo assays showed that only ferric sulfate treatments were able to significantly reduce As bioaccessibility and bioavailability with TER at the highest application of 0.06 ± 0.00 and 0.14 ± 0.04 respectively. This study highlights the potential application of ferric sulfate treatment for the immobilization of Pb and As in co-contaminated soils.
| S-EPMC10843775 | biostudies-literature