SciCombinator

Discover the most talked about and latest scientific content & concepts.

Journal: Environmental health and toxicology

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Inferring causality is necessary to achieve the goal of epidemiology, elucidating the cause of disease. Causal inference is conducted in three steps; evaluation of validity of the study, inference of general causality and inference of individual causality. To evaluate validity of the study, we proposed a checklist which focuses on biases and generalizability. For general causal inference, Hill’s 9 viewpoints can be used. Individual causality can be inferred based on the general causality and evidence of exposure. Additional considerations may be needed for social or legal purposes; however, these additional considerations should be based on the scientific truth elucidated by the causal inference described in the present article.

Concepts: Reasoning, Epidemiology, Inference, Causality, Logic

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Carcinogenesis is a complex process involving in genotoxic and non-genotoxic pathways. Carcinogenic potential of AgNPs has been predicted by genotoxic effects using several in vitro and in vivo models. However, there is no little information on non-genotoxic effects of AgNPs for carcinogenesis. In vitro cell transformation assay (CTA) can provide specific and sensitive evidence to predict the tumorigenic potential of a chemical, which cannot be supplied by genotoxicity testing. Therefore, we carried out CTA in Balb/c 3T3 A31-1-1 cells to evaluate the carcinogenic potential of silver nanoparticle (AgNPs). Colony forming efficiency (CFE) assay, and crystal violet (CV) assay were carried out to find cytotoxicity of AgNPs. Cytokinesis-block micronucleus assay (CBMN) and CTA in Balb/c 3T3 A31-1-1 cells were performed to predict in vitro carcinogenic potential of AgNPs. In CBMN assay, AgNPs (10.6 ug/mL) induced a significant increase of the micronucleus formation indicating that AgNPs had genotoxicity and could be an initiator for carcinogenesis. In CTA assay to assess carcinogenic potential of AgNPs, cells exposed to AgNPs for 72 h significantly induced morphological neoplastic transformation at all treated doses (0.17, 0.66, 2.65, 5.3, and 10.6 ug/mL) and Tf (transformation frequency) showed a significant increase in a dose-dependent manner. These results indicated that short-term exposure (72 h) to AgNPs had in vitro carcinogenetic potency in Balb/c 3T3 A31-1-1 cells.

Concepts: Toxicology, Cancer, Nanotechnology, Carcinogenesis, In vivo, In vitro, Mutagen, Oncology

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In this study, the associations between mercury exposure and cholesterol profiles were analyzed, and increased mercury levels and cholesterol profiles according to the amount of fish consumption were evaluated.

Concepts: According to Jim, Health, Mercury, Nutrition

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Complexity and heterogeneity of soil samples have often implied the inclusion of purification steps in conventional DNA extraction for PCR assays. Unfortunately the purification steps are also time and labor intensive. Therefore the necessity of DNA purification was re-visited and investigated for a variety of environmental soil samples that contained various amounts of PCR inhibitors.

Concepts: Gene expression, Labor, Soil, Laboratory techniques, Archaea, Polymerase chain reaction, Molecular biology, DNA

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The purpose of this study is to examine whether water and air pollutants have a relationship with an increase in the genetic disorders Turner syndrome and Down syndrome, which are caused by congenital chromosomal abnormalities, and to generate a hypothesis about the genetic health effects of environmental pollutants. A panel regression based on random effect was conducted on South Korea’s metropolitan councils from 2012 to 2014. The dependent variable was the number of Turner syndrome and Down syndrome cases, and the main independent variables were those regarding the water and air pollution. Air pollutants did not have a significant impact on the number of Turner syndrome and Down syndrome cases; however, the increase in number of wastewater discharge companies did have a significant relationship with the number of cases. The more the number of wastewater discharge companies, the more the number Turner syndrome and Down syndrome cases were observed. Therefore, scientific investigation on water and air pollutants in relation with genetic health effects needs to be performed.

Concepts: Aneuploidy, Biofilter, Acid rain, Environmentalism, Cruise ship pollution, Scientific method, Genetic disorders, Pollution

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The rapidly increasing annual global volumes and the inherently valuable fractions of e-waste have created an avenue for individuals in Agbogbloshie, Accra, Ghana to make a living by utilizing unconventional, uncontrolled, primitive and crude procedures to recycle and recover valuable metals from these wastes. The current form of recycling procedures releases hazardous fractions such as heavy metals into the soils posing a significant risk to ecology and human health. 132 soil samples based on 100 m grid intervals were collected using handheld GPS and analyzed for Cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), lead (Pb) and zinc (Zn) heavy metals. Using geostatistical techniques and sediment quality guidelines (SQGs), this research seeks to assess the potential risk these heavy metals posed to the proposed Korle Ecological Restoration Zone by informal e-waste processing site in Agbogbloshie, Accra, Ghana. Analysis of heavy metals revealed concentrations exceeded the regulatory limits of both Dutch and Canadian Soil Quality and Guidance Values, and that the ecological risk posed by the heavy metals extended beyond the main burning and dismantling sites of the informal recyclers to the school, residential, recreational, clinic, farm and worship areas. Cr, Cu, Pb and Zn heavy metals reveal normal distribution, spatial variability and spatial autocorrelation. Further analysis reveals, Hg>Cd>Pb>Cu>Zn>Cr decreasing toxicity order to contribute significantly to the potential ecological risk in the study area.

Concepts: Waste management, Chromium, Cadmium, Copper, Recycling, Heavy metal music, Zinc, Lead

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It is widely accepted that relatively small parts of chronic diseases can be explained by genetic factors alone. Although environmental exposures are important to evaluate chronic diseases comprehensively, they are not assessed with sufficient comprehensiveness and accuracy in contrast to genome. To emphasize the importance of more complete evaluation of environmental exposure, the concept of exposome, which indicates the entirety of environmental exposure from conception onwards, was introduced in 2005. Since 2010s, several epidemiological studies, such as the Human Early-Life Exposome (HELIX) project, have applied the exposome concept. The exposome consists of three overlapping domains: a general external, specific external, and internal environment. General external factors include broader socioeconomic environment, and specific external factors include lifestyles, occupation, and pollutant exposure. Internal factors include biological effects and response. Because the exposome covers exposures from conception to death, birth cohort is an important part of the exposome study. Although there is no established consensus in selecting what, when, and where to measure exposome yet, use of omics analyses, especially metabolome, should be considered to implement the exposome concept in the birth cohort. The exposome needs to be measured repeatedly in certain important phases of life stage, such as during pregnancy and infancy. To perform exposome-informed epidemiologic study, untargeted data-driven approach with dimension reduction techniques needs to be developed and refined. The exposome concept has a potential to make a breakthrough in the limitations of conventional epidemiology. National and international consorted efforts are required for future exposome studies.

Concepts: Demography, Epidemiological study, Public health, Biology, Biostatistics, Disease, Infectious disease, Epidemiology

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Zinc oxide nanoparticles (ZnO NPs) and titanium dioxide nanoparticles (TiO2 NPs) are well known as photoreactive NPs. Various phototoxicity of ZnO NPs and TiO2 NPs on several organisms were reported. There was still necessity to evaluate toxicity of photoreactive ZnO NPs and TiO2 NPs due to species-specific effects under various irradiation conditions. We compared acute toxicity of Moina macrocopa under visible, UVA, and UVB irradiations, according to Organization for Economic Cooperation and Development guidelines for the testing of chemicals (Test No. 202). The sensitivity of ZnO NPs for M. macrocopa was UVB > UVA > visible light irradiation. There were no significant lethal and immobile effects of TiO2 NPs on juveniles under all the irradiations, in the tested concentrations of TiO2 NPs. Photoreactive NPs have a potential and accelerated toxicity on organisms in the ambient environments.

Concepts: Toxicology, Dye-sensitized solar cell, Oxides, Oxide, Zinc oxide, Sunscreen, Ultraviolet, Titanium dioxide

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This study was conducted to evaluate the ability of plants to purify indoor air by observing the effective reduction rate among pollutant types of particulate matter and volatile organic compounds. Particulate matter and four types of volatile organic compounds were measured in a new building that is less than 3 years old and under three different conditions: before applying the plant, after applying the plant, and a room without a plant. The removal rate of each pollutant type due to the plant was also compared and analyzed. In the case of indoor particulate matter, the removal effect was negligible because of outdoor influence. However, 9% of benzene, 75% of ethylbenzene, 72% of xylene, 75% of styrene, 50% of formaldehyde, 36% of acetaldehyde, 35% of acrolein with acetone, and 85% of toluene were reduced. The purification of indoor air by natural ventilation is meaningless because the ambient particulate matter concentration has recently been high. However, contamination by gaseous materials such as volatile organic compounds can effectively be removed through the application of plants.

Concepts: Pollutants, Toluene, Volatile organic compound, Photosynthesis, Xylene, Ethylbenzene, Hazardous air pollutants, Benzene

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Recently, epidemiologic studies have shown that the lack of vitamin D levels may be associated with high asthma prevalence, but its effect is still controversial, depending on season, area, and food consumption. We aimed to examine the association of serum vitamin D levels with the prevalence of pediatric asthma in Korea. A total of 80 children (50 asthmatic children and 30 healthy controls) aged 6-14 years were participated in this study. Serum 25-hydroxy vitamin D (vitamin D) levels were measured and compared between the two groups. Moreover, the relationship of serum vitamin D levels with results of pulmonary function test and environmental factors (lifestyle habits and residential factors) collected by a questionnaire survey were examined in asthmatic patients. Serum vitamin D levels in asthmatic children (16.63 ± 4.20 ng/mL) were significantly lower than that in healthy controls (24.24 ± 6.76 ng/mL) (P<0.05). Also, we found that the prevalence of asthma increase to 0.79-fold (OR, 0.788; 95% C.I., 0.707-0.879; P<0.001) as serum vitamin D level is 1 ng/mL decreases. The increased time spent in outdoor could affect the increases of vitamin D levels significantly. However, no associations of vitamin D level with pulmonary function and residential environmental factors (i.e., housing type, living floor, and indoor activity time) were observed. Our findings suggest that serum vitamin D levels were also associated with pediatric asthma in Korea. Moreover, management of vitamin D level in asthmatic children would be a promising approach for preventing exaggeration of their severity.

Concepts: Spirometry, Nutrition, Peak flow meter, Vitamin C, Vitamins, Epidemiology, Asthma, Vitamin D